Patent Publication Number: US-10778824-B2

Title: Pen-type handset

Description:
TECHNICAL FIELD 
     The present invention relates to a handset. 
     BACKGROUND ART 
     Conventionally, various different handsets have been proposed for use in various scenes. As handsets, there has been proposed a mobile telephone in which a bone conduction speaker is employed to provide a mobile telephone permitting conversation to be conducted even in the presence of loud noise, the mobile telephone being provided with the bone conduction speaker as well as with external auditory meatus stoppage means (Patent Document 1). On the other hand, in another proposed method for using a bone conduction speaker, a manual operation is used to adjust the pressure of contact between the tragus and a vibrating surface to be brought into contact with the tragus, whereby the ratio at which audio information through cartilage conduction and audio information through air conduction are transmitted can be altered in accordance with the magnitude of outside noise (Patent Document 2). In yet another proposal, a piezoelectric element is used as a vibration source of bone conduction. A further proposal for a mobile telephone is a wireless communication function headset that is wirelessly communicatively connected to a communication apparatus capable of audio communication via a communication network, the wireless communication function headset permitting audio communication with a party on the line via the communication apparatus (Patent Document 3). In yet another proposal, an eyeglasses-type interface device is provided with an audio unit that includes a bone conduction earphone, a microphone, and a display unit for displaying, on a lens, movie information that has been sent to a wireless communication unit from a mobile telephone or the like (Patent Document 4). 
     LIST OF CITATIONS 
     Patent Literature 
     [Patent Document 1] JP-A 2003-348208 
     [Patent Document 2] JP-B 4541111 
     [Patent Document 3] JP-A 2006-86581 
     [Patent Document 4] JP-A 2005-352024 
     SUMMARY OF INVENTION 
     Technical Problem 
     However, there are yet many problems to be reviewed in relation to handsets. 
     In view of the above, an object of the present invention is to provide useful pen-type handsets improved hearing devices and improved vibration units for hearing devices. 
     Solution to Problem 
     According to one aspect of the present invention, a pen-type handset is provided that includes: a clip portion; a cartilage-conduction vibration source which conducts vibration to the clip portion; a sound source unit which feeds the cartilage-conduction vibration source with a sound signal in an audible range; a microphone; and a wireless communication unit which receives a sound signal for the sound source unit and which transmits sound from the microphone. 
     According to a specific feature of the present invention, the pen-type handset further includes: a main body; and a vibration isolating means for isolating conduction of vibration from the clip portion to the main body. According to a more specific feature of the present invention, the vibration of the cartilage-conduction vibration source is conducted to the clip portion, and between the cartilage-conduction vibration source and the main body, a vibration isolating material is interposed as the vibration isolating means. According to a more specific feature, the clip portion is formed of an elastic body, the cartilage-conduction vibration source is provided in the clip portion, and the clip portion is supported on the main body such that the cartilage-conduction vibration source does not make direct contact with the main body. According to another more specific feature, the cartilage-conduction vibration source is supported on the clip portion, and the clip portion is supported on the main body via the vibration isolating material. 
     According to another specific feature of the present invention, the vibration isolating means is a vibration conduction unit which switches between whether or not to conduct the vibration of the cartilage-conduction vibration source to the main body; when the clip portion is closed, the vibration conduction unit does not conduct the vibration of the cartilage-conduction vibration source to the main body, and when the clip portion is open, the vibration conduction unit conducts the vibration of the cartilage-conduction vibration source to the main body. 
     According to another specific feature of the present invention, the pen-type handset further includes an incoming-call display unit; when the clip portion is closed, the incoming-call display unit is allowed to operate and, when the clip portion is open, the incoming-call display unit is prohibited from operating. According to another specific feature of the present invention, the pen-type handset further includes an operation unit; when the clip portion is closed, operation on the operation unit is validated and, when the clip portion is open, operation on the operation unit is invalidated. 
     According to another specific feature of the present invention, the pen-type handset responds to an incoming call on detecting the clip portion shifting from an open state to a closed state. According to another specific feature of the present invention, the pen-type handset further includes a control unit which feeds the cartilage-conduction vibration source with a signal in a sense-of-vibration range for incoming call notification. According to another specific feature of the present invention, the pen-type handset further includes a storage unit; during a search for call origination, data on a communication partner is stored in the storage unit from the outside, and after use of the data, the data on the communication partner is erased from the storage unit. 
     According to another specific feature of the present invention, the pen-type handset, when it is used, performs voiceprint recognition. According to another specific feature of the present invention, the pen-type handset further includes a main body, and the diameter of the cross section of the main body is 1.5 cm or less. 
     According to another aspect of the present invention, a pen-type handset is provided that includes: a cartilage conduction unit; a cartilage-conduction vibration source which conducts vibration to the cartilage conduction unit; a sound source unit which feeds the cartilage-conduction vibration source with a sound signal in an audible range; a microphone; a wireless communication unit which receives a sound signal for the sound source unit and which transmits sound from the microphone; a main body; and a vibration isolating means for isolating conduction of vibration from the cartilage conduction unit to the main body. 
     According to a specific feature of the present invention, the vibration of the cartilage-conduction vibration source is conducted to the cartilage conduction unit, and between the cartilage-conduction vibration source and the main body, a vibration isolating material is interposed as the vibration isolating means. According to a more specific feature of the present invention, the cartilage conduction unit is formed of an elastic body, the cartilage-conduction vibration source is provided in the cartilage conduction unit, and the cartilage conduction unit is supported on the main body such that the cartilage-conduction vibration source does not make direct contact with the main body. According to a more specific feature of the present invention, the vibration isolating means is a vibration conduction unit which switches between whether or not to conduct the vibration of the cartilage-conduction vibration source to the main body. 
     According to another specific feature of the present invention, the pen-type handset further includes an incoming-call display unit; when the vibration conduction unit does not conduct the vibration of the cartilage-conduction vibration source to the main body, the incoming-call display unit is allowed to operate and, when the vibration conduction unit conducts the vibration of the cartilage-conduction vibration source to the main body, the incoming-call display unit is prohibited from operating. According to another specific feature of the present invention, the pen-type handset further includes an operation unit; when the vibration conduction unit does not conduct the vibration of the cartilage-conduction vibration source to the main body, operation on the operation unit is validated and, when the vibration conduction unit conducts the vibration of the cartilage-conduction vibration source to the main body, operation on the operation unit is invalidated. 
     According to yet another aspect of the present invention, a pen-type handset is provided that includes: a cartilage conduction unit; a cartilage-conduction vibration source which conducts vibration to the cartilage conduction unit; a sound source unit which feeds the cartilage-conduction vibration source with a sound signal in an audible range; a microphone; a wireless communication unit which receives a sound signal for the sound source unit and which transmits sound from the microphone; and a main body. Here, the diameter of the cross section of the main body is 1.5 cm or less. 
     Advantageous Effects of the Invention 
     As described above, according to the present invention, it is possible to provide useful pen-type handsets. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view illustrating a first embodiment of a mobile telephone according to an aspect of the present invention (first embodiment); 
         FIG. 2  is a side view of the first embodiment illustrating the functions of the state of right ear use and the state of left ear use; 
         FIG. 3  is a block diagram of the first embodiment; 
         FIG. 4  is a flowchart of the operation of a controller in the first embodiment of  FIG. 2 ; 
         FIG. 5  is a perspective view illustrating a second embodiment of a mobile telephone according to an aspect of the present invention (second embodiment); 
         FIG. 6  is a perspective view illustrating a third embodiment of a mobile telephone according to an aspect of the present invention (third embodiment); 
         FIG. 7  is a perspective view illustrating a fourth embodiment of a mobile telephone according to an aspect of the present invention (fourth embodiment); 
         FIG. 8  is a block diagram of the fourth embodiment; 
         FIG. 9  is a conceptual block diagram illustrating the elements of the configuration pertaining to an earplug bone conduction effect of the fourth embodiment; 
         FIG. 10  is a flow chart of the operation of the controller in the fourth embodiment of  FIG. 8 ; 
         FIG. 11  is a perspective view illustrating a fifth embodiment of a mobile telephone according to an aspect of the present invention (fifth embodiment); 
         FIG. 12  is a flow chart of the operation of the controller in the fifth embodiment of  FIG. 11 ; 
         FIG. 13  is a perspective view illustrating a sixth embodiment of a mobile telephone according to an aspect of the present invention, where  FIG. 13A  is a front perspective view,  FIG. 13B  is a rear perspective view, and  FIG. 13C  is a cross-sectional view along the B-B cross-section of the rear perspective view of  FIG. 13B  (sixth embodiment); 
         FIG. 14  is a flow chart of the operation of the controller in the sixth embodiment of  FIG. 13 ; 
         FIG. 15  is a perspective view illustrating a seventh embodiment of a mobile telephone according to an aspect of the present invention, where  FIG. 15A  is a front view,  FIG. 15B  is a rear view, and  FIG. 15C  is an elemental cross-sectional view along the B-B cross-section of the rear perspective view of  FIG. 15B  (seventh embodiment); 
         FIG. 16  is a flow chart of the operation of the controller in the seventh embodiment of  FIG. 15 ; 
         FIG. 17  is a perspective view illustrating an eighth embodiment of a mobile telephone according to an aspect of the present invention, where  FIG. 17A  is a front view, 
         FIG. 17B  is a rear view, and  FIG. 17C  is an elemental cross-sectional view along the B-B cross-section of the rear perspective view of  FIG. 17B  (eighth embodiment); 
         FIG. 18  is a perspective view illustrating a ninth embodiment of a mobile telephone according to an aspect of the present invention, where  FIG. 18A  is a front view, 
         FIG. 18B  is a rear view, and  FIG. 18C  is an elemental cross-sectional view along the B-B cross-section of the rear perspective view of  FIG. 18B  (ninth embodiment); 
         FIG. 19  is a perspective view illustrating a tenth embodiment of the mobile telephone according to an aspect of the present invention (tenth embodiment); 
         FIG. 20  is a perspective view illustrating an eleventh embodiment of a mobile telephone according to an aspect of the present invention (eleventh embodiment); 
         FIG. 21  is a side view of the eleventh embodiment illustrating the functions of the state of right ear use and the state of left ear use; 
         FIG. 22  is a perspective view illustrating a twelfth embodiment of a mobile telephone according to an aspect of the present invention (twelfth embodiment); 
         FIG. 23  is a flow chart of the operation of the controller in the twelfth embodiment of  FIG. 22 ; 
         FIG. 24  is a perspective view illustrating a thirteenth embodiment of a mobile telephone according to an aspect of the present invention (thirteenth embodiment); 
         FIG. 25  is a perspective view illustrating a fourteenth embodiment of a mobile telephone according to an aspect of the present invention (fourteenth embodiment); 
         FIG. 26  is a diagram of the system of a fifteenth embodiment according to an aspect of the present invention (fifteenth embodiment); 
         FIG. 27  is a diagram of the system of a sixteenth embodiment according to an aspect of the present invention (sixteenth embodiment); 
         FIG. 28  is a block diagram of the sixteenth embodiment; 
         FIG. 29  is a block diagram of a seventeenth embodiment (seventeenth embodiment); 
         FIG. 30  is a flow chart of the operation of the controller of an incoming/outgoing-talk unit in the seventeenth embodiment of  FIG. 29 ; 
         FIG. 31  is a flow chart of the operation of the controller of the incoming/outgoing talk unit in an eighteenth embodiment (eighteenth embodiment); 
         FIG. 32  is a diagram of the system of a nineteenth embodiment according to an aspect of the present invention (nineteenth embodiment); 
         FIG. 33  is a diagram of the system of a twentieth embodiment according to an aspect of the present invention (twentieth embodiment); 
         FIG. 34  is a side view of the elements of a twenty-first embodiment according to an aspect of the present invention (twenty-first embodiment); 
         FIG. 35  is a top view of a twenty-second embodiment according to an aspect of the present invention (twenty-second embodiment); 
         FIG. 36  is a block diagram of a twenty-third embodiment according to an aspect of the present invention (twenty-third embodiment); 
         FIG. 37  is a diagram of the system of a twenty-fourth embodiment according to an aspect of the present invention (twenty-fourth embodiment); 
         FIG. 38  is block diagram of a twenty-fifth embodiment according to an aspect of the present invention (twenty-fifth embodiment); 
         FIG. 39  is a cross-sectional view of the elements of the twenty-fifth embodiment; 
         FIG. 40  is a perspective view illustrating a modification example of the tenth embodiment in  FIG. 19 ; 
         FIG. 41  is a perspective view of a twenty-sixth embodiment according to an aspect of the present invention (twenty-sixth embodiment); 
         FIG. 42  is a block diagram of the twenty-sixth embodiment of  FIG. 41 ; 
         FIG. 43  is a flow chart relating to the operation of the controller in the twenty-sixth embodiment of  FIG. 42 , and shows step S 42  of  FIG. 10  in more detail; 
         FIG. 44  is a perspective view and cross-sectional view of a twenty-eighth embodiment according to an aspect of the present invention (twenty-eighth embodiment); 
         FIG. 45  is a cross-sectional view illustrating a first modification example and a second modification example of the twenty-eighth embodiment; 
         FIG. 46  is a cross-sectional view of a third modification example and a fourth modification example of the twenty-eighth embodiment; 
         FIG. 47  is a perspective view illustrating a twenty-ninth embodiment according to an aspect of the present invention, and a modification example thereof (twenty-ninth embodiment); 
         FIG. 48  is a perspective view and a cross-sectional view of a thirtieth embodiment according to an aspect of the present invention (thirtieth embodiment); 
         FIG. 49  is a longitudinal cross-sectional view and a latitudinal cross-sectional view of a thirty-first embodiment according to an aspect of the present invention (thirty-first embodiment); 
         FIG. 50  is a cross-sectional view illustrating a first modification example and a second modification example of the thirty-first embodiment; 
         FIG. 51  is a perspective view of a thirty-second embodiment according to an aspect of the present invention, configured as a piezoelectric bimorph element adapted for use in the mobile telephone (thirty-second embodiment); 
         FIG. 52  is a transparent perspective view of a thirty-third embodiment according to an aspect of the present invention, and a modification example thereof (thirty-third embodiment); 
         FIG. 53  is an external perspective view of the thirty-third embodiment and the modification example thereof; 
         FIG. 54  is a transparent perspective view of a thirty-fourth embodiment according to an aspect of the present invention (thirty-fourth embodiment); 
         FIG. 55  is a transparent perspective view relating to a thirty-fifth embodiment according to an aspect of the present invention (thirty-fifth embodiment); 
         FIG. 56  is a transparent perspective view relating to a thirty-sixth embodiment according to an aspect of the present invention (thirty-sixth embodiment); 
         FIG. 57  is a transparent perspective view relating to a thirty-seventh embodiment according to an aspect of the present invention (thirty-seventh embodiment); 
         FIG. 58  is a cross-sectional block diagram relating a thirty-eighth embodiment according to an aspect of the present invention (thirty-eighth embodiment); 
         FIG. 59  is a back surface transparent view and cross-sectional view illustrating the manner in which a cartilage conduction vibration source is anchored to the mobile telephone in the thirty-eighth embodiment; 
         FIG. 60  is a flow chart of the operation of a controller  3439  in the thirty-eighth embodiment of  FIG. 58 ; 
         FIG. 61  is a cross-sectional view of a thirty-ninth embodiment according to an aspect of the present invention, and various modification examples thereof (thirty-ninth embodiment); 
         FIG. 62  is a cross-sectional view and a transparent perspective view of the elements of a fortieth embodiment according to an aspect of the present invention as well as various modification examples thereof (fortieth embodiment); 
         FIG. 63  is a cross-sectional view of a forty-first embodiment according to an aspect of the present invention (forty-first embodiment); 
         FIG. 64  is a cross-sectional view of various modification examples of the forty-first embodiment; 
         FIG. 65  is a cross-sectional view relating to a forty-second embodiment according to an aspect of the present invention (forty-second embodiment); 
         FIG. 66  is a cross-sectional view relating to a forty-third embodiment according to an aspect of the present invention (forty-third embodiment) 
         FIG. 67  is a cross-sectional view relating to a forty-fourth embodiment according to an aspect of the present invention (forty-fourth embodiment); 
         FIG. 68  is a cross-sectional view relating to a forty-fifth embodiment according to an aspect of the present invention (forty-fifth embodiment); 
         FIG. 69  is a perspective view and a cross-sectional view relating to a forty-sixth embodiment according to an aspect of the present invention (forty-sixth embodiment); 
         FIG. 70  is a perspective view and a cross-sectional view relating to a forty-seventh embodiment according to an aspect of the present invention (forty-seventh embodiment); 
         FIG. 71  is a perspective view and a cross-sectional view relating to a modification example of the forty-sixth embodiment according to an aspect of the present invention 
         FIG. 72  is a perspective view and a cross-sectional view relating to a forty-eighth embodiment according to an aspect of the present invention (forty-eighth embodiment); 
         FIG. 73  is an enlarged cross-sectional view of the elements of the forty-eighth embodiment and a modification example thereof; 
         FIG. 74  is a perspective view and a cross-sectional view relating to a forty-ninth embodiment according to an aspect of the present invention, and a modification example thereof (forty-ninth embodiment); 
         FIG. 75  is a block diagram combining a partial cross-sectional view relating to a fiftieth embodiment according to an aspect of the present invention (fiftieth embodiment); 
         FIG. 76  is a block diagram combining a partial cross-sectional view relating to a fifty-first embodiment according to an aspect of the present invention (fifty-first embodiment); 
         FIG. 77  is a cross-sectional view and interior block diagram relating to a fifty-second embodiment according to an aspect of the present invention (fifty-second embodiment); 
         FIG. 78  is a perspective view and cross-sectional views relating to the fifty-second embodiment of  FIG. 77 ; 
         FIG. 79  is a graph illustrating an example of measurement data of the mobile telephone configured on the basis of the forty-sixth embodiment of  FIG. 69 ; 
         FIG. 80  is a side view and a cross-sectional view of an ear, intended to illustrate the relationship between the detailed structure of the ear and the mobile telephone of the present invention; 
         FIG. 81  is a block diagram of a fifty-third embodiment according to an aspect of the present invention (fifty-third embodiment); 
         FIG. 82  is a block diagram of a fifty-fourth embodiment according to an aspect of the present invention (fifty-fourth embodiment); 
         FIG. 83  is a perspective view and a cross-sectional view of a fifty-fifth embodiment according to an aspect of the present invention (fifty-fourth embodiment); 
         FIG. 84  is a block diagram of the fifty-fifth embodiment of  FIG. 83 ; 
         FIG. 85  s a side view intended to describe the distribution of vibration energy in a mobile telephone in the fifty-fifth embodiment of  FIG. 83 ; 
         FIG. 86  is a perspective view and a cross-sectional view of a fifty-sixth embodiment according to an aspect of the present invention (fifty-sixth embodiment); 
         FIG. 87  is a block diagram of a fifty-seventh embodiment according to an aspect of the present invention (fifty-seventh embodiment); 
         FIG. 88  is a perspective view and a cross-sectional view of a fifty-eighth embodiment according to an aspect of the present invention (fifty-eighth embodiment); 
         FIG. 89  is a perspective view and a cross-sectional view of a fifty-ninth embodiment according to an aspect of the present invention (fifty-ninth embodiment); 
         FIG. 90  is a perspective view and a cross-sectional view of a sixtieth embodiment according to an aspect of the present invention (sixtieth embodiment); 
         FIG. 91  is a perspective view and a cross-sectional view of a sixty-first embodiment according to an aspect of the present invention (sixty-first embodiment) 
         FIG. 92  is a perspective view and a side view of a sixty-second embodiment according to an aspect of the present invention (sixty-second embodiment); 
         FIG. 93  is a block diagram of the sixty-second embodiment of  FIG. 93 ; 
         FIG. 94  is side cross sectional views of cordless handsets in the sixty-second embodiment of  FIG. 92  and modification examples thereof; 
         FIG. 95  is a cross sectional view of a sixty-third embodiment according to an aspect of the present invention (sixty-third embodiment); 
         FIG. 96  is a perspective view, a cross sectional view, and a top view of a sixty-fourth embodiment according to an aspect of the present invention (sixty-fourth embodiment); 
         FIG. 97  is a perspective view, a cross sectional view, and a top view of a sixty-fifth embodiment according to an aspect of the present invention (sixty-fifth embodiment); 
         FIG. 98  is a perspective view, a cross sectional view, and a top view of a sixty-sixth embodiment according to an aspect of the present invention (sixty-sixth embodiment); 
         FIG. 99  is a perspective view and a cross sectional view of a sixty-seventh embodiment according to an aspect of the present invention (sixty-seventh embodiment); 
         FIG. 100  is a cross sectional view of a sixty-eighth embodiment according to an aspect of the present invention (sixty-eighth embodiment); 
         FIG. 101  is a system configuration diagram and a usage description diagram of a sixty-ninth embodiment according to an aspect of the present invention (sixty-ninth embodiment); 
         FIG. 102  is a block diagram of the sixty-ninth embodiment; 
         FIG. 103  is a perspective view of a seventieth embodiment according to an aspect of the present invention (seventieth embodiment); 
         FIG. 104  is a block diagram of the seventieth embodiment; 
         FIG. 105  is a perspective view and a cross sectional view of a seventy-first embodiment according to an aspect of the present invention (seventy-first embodiment); 
         FIG. 106  is a block diagram of the seventy-first embodiment; 
         FIG. 107  is a block diagram relating to a seventy-second embodiment according to an aspect of the present invention (seventy-second embodiment); 
         FIG. 108  is timing charts of power supply control to a charge pump circuit in the seventy-second embodiment; 
         FIG. 109  is flowchart of operation of an application processor in the seventy-second embodiment; 
         FIG. 110  is a perspective view relating to a seventy-third embodiment according to an aspect of the present invention (seventy-third embodiment); 
         FIG. 111  is perspective views showing several video phone modes in the seventy-third embodiment; 
         FIG. 112  is a flowchart showing videoconferencing processing in the seventy-third embodiment; 
         FIG. 113  is a flowchart showing the details of Step S 376  of  FIG. 112 ; 
         FIG. 114  is a block diagram relating to a seventy-fourth embodiment according to an aspect of the present invention (seventy-fourth embodiment) 
         FIG. 115  is a block diagram relating to a seventy-fifth embodiment according to an aspect of the present invention (seventy-fifth embodiment); 
         FIG. 116  is a block diagram relating to a seventy-sixth embodiment according to an aspect of the present invention (seventy-sixth embodiment); 
         FIG. 117  is a block diagram relating to a seventy-seventh embodiment according to an aspect of the present invention (seventy-seventh embodiment); 
         FIG. 118  is a cross sectional view of a front surface and a side surface relating to a seventy-eighth embodiment according to an aspect of the present invention (seventy-eighth embodiment); 
         FIG. 119  is a cross sectional view of a front surface and a side surface relating to a seventy-ninth embodiment according to an aspect of the present invention (seventy-ninth embodiment); 
         FIG. 120  is a cross sectional view of a front surface and a side surface relating to an eightieth embodiment according to an aspect of the present invention (eightieth embodiment); 
         FIG. 121  is a cross sectional view of a side surface relating to an eighty-first embodiment according to an aspect of the present invention, and a first modification example and second modification example thereof (eighty-first embodiment); 
         FIG. 122  is a block diagram relating to an eighty-second embodiment according to an aspect of the present invention (eighty-second embodiment); 
         FIG. 123  is a flowchart of an application processor in the eighty-second embodiment of  FIG. 122 ; 
         FIG. 124  is a perspective view relating to an eighty-third embodiment according to an aspect of the present invention (eighty-third embodiment); 
         FIG. 125  is a perspective view showing a modification example of the eighty-third embodiment of  FIG. 124 ; 
         FIG. 126  is a perspective view and a cross sectional view relating to an eighty-fourth embodiment according to an aspect of the present invention (eighty-fourth embodiment); 
         FIG. 127  is a block diagram of the eighty-fourth embodiment of  FIG. 126 ; 
         FIG. 128  depicts cross sectional views of a modification example of the eighty-fourth embodiment of  FIG. 126 ; 
         FIG. 129  is a block diagram of a modification example of the eighty-fourth embodiment of  FIG. 128 ; 
         FIG. 130  is a perspective view and a cross sectional view relating to an eighty-fifth embodiment according to an aspect of the present invention and a modification example thereof (eighty-fifth embodiment); 
         FIG. 131  is a block diagram relating to an eighty-sixth embodiment of the present invention (eighty-sixth embodiment); 
         FIG. 132  depicts graphs relating to the eighty-sixth embodiment of  FIG. 131 , which show image depictions of frequency characteristics of a piezoelectric bimorph element, of ear cartilage, and of the drive output to the piezoelectric bimorph element; 
         FIG. 133  is a flowchart of a controller in the eighty-sixth embodiment of  FIG. 131 ; 
         FIG. 134  depicts perspective views showing a modification example of the eighty-sixth embodiment of  FIG. 131 ; 
         FIG. 135  is a block diagram relating to an eighty-seventh embodiment of the present invention (eighty-seventh embodiment); 
         FIG. 136  is a perspective view and cross sectional views relating to an eighty-eighth embodiment of the present invention (eighty-eighth embodiment); 
         FIG. 137  is a side view describing a call condition in the eighty-eighth embodiment of  FIG. 136 ; 
         FIG. 138  depicts cross sectional views showing modification examples of the eighty-eighth embodiment of  FIG. 136 ; 
         FIG. 139  is a system configuration diagram of an eighty-ninth embodiment of the present invention (eighty-ninth embodiment); 
         FIG. 140  is a system configuration diagram of a ninetieth embodiment of the present invention (ninetieth embodiment); 
         FIG. 141  is cross sectional views and a block diagram relating to a ninety-first embodiment of the present invention (ninety-first embodiment); 
         FIG. 142  is a system configuration diagram of a ninety-second embodiment of the present invention (ninety-second embodiment); 
         FIG. 143  depicts side views of an ear, for showing a modification example of the ninety-second embodiment; 
         FIG. 144  is a back view and a block diagram of a ninety-third embodiment of the present invention (ninety-third embodiment); 
         FIG. 145  is a back cross sectional view and a block diagram of a ninety-fourth embodiment of the present invention (ninety-fourth embodiment); 
         FIG. 146  is a block diagram of a ninety-fifth embodiment of the present invention (ninety-fifth embodiment); 
         FIG. 147  is a perspective view and a cross-sectional view of a ninety-sixth embodiment of the present invention (ninety-sixth embodiment); 
         FIG. 148  is a block view of a mobile telephone portion of the ninety-sixth embodiment of  FIG. 147 ; 
         FIG. 149  is flowchart showing the function of a control unit of the ninety-sixth embodiment of  FIG. 148 ; 
         FIG. 150  is a front perspective view of a ninety-seventh embodiment of the present invention (ninety-seventh embodiment); 
         FIG. 151  is a flowchart showing the control unit function of the ninety-seventh embodiment of the present invention; 
         FIG. 152  is a flowchart showing the details of step S 554  and step S 560  of  FIG. 150 ; 
         FIG. 153  is a cross-sectional view and a block view related to a ninety-eighth embodiment of the present invention (ninety-eighth embodiment); 
         FIG. 154  is a table showing measurement values of the ninety-eighth embodiment; 
         FIG. 155  is a circuit diagram showing the details of a combination circuit of a voltage booster circuit and an analog output amplifier that can be used in the seventy-fourth embodiment and the seventy-fifth embodiment shown in  FIG. 114  and  FIG. 115 ; 
         FIG. 156  is a diagram of the system of a ninety-ninth embodiment of the present invention (ninety-ninth embodiment); 
         FIG. 157  is a side view of the ear-hooking unit in the various modifications of the ninety-ninth embodiment of  FIG. 156 ; 
         FIG. 158  perspective view and a cross-sectional view of a one-hundredth embodiment of the present invention (one-hundredth embodiment); 
         FIG. 159  is a schematic cross-sectional view and a circuit diagram showing the details of the structure of the piezoelectric bimorph of the one-hundredth embodiment shown in  FIG. 158 ; 
         FIG. 160  is cross-sectional view for describing the configuration for mass-producing the piezoelectric bimorph module in the one-hundredth embodiment of  FIG. 158 ; 
         FIG. 161  is a block view related to a one-hundred first embodiment of the present invention (one-hundred first embodiment); 
         FIG. 162  is a block view of a first modification of the one-hundred first embodiment shown in  FIG. 161 ; 
         FIG. 163  is a block view of a second modification of the one-hundred first embodiment shown in  FIG. 161 ; 
         FIG. 164  is a partially cutaway detailed circuit diagram of when the feature of the one-hundred first embodiment of  FIG. 161  has been applied to the circuit of  FIG. 155 ; 
         FIG. 165  is a block view related to a one-hundred second embodiment of the present invention (one-hundred first embodiment); 
         FIG. 166  is a flowchart showing the function of the application processor in the one-hundred second embodiment; 
         FIG. 167  is a graph for visually showing the frequency characteristics of the one-hundred second embodiment; 
         FIG. 168  is a perspective view and a cross-sectional view of a one-hundred third embodiment of the present invention (one-hundred third embodiment); 
         FIG. 169  is an enlarged cross-sectional view of the principal elements of the one-hundred third embodiment shown in  FIG. 168(D) ; 
         FIG. 170  is a perspective view and a cross-sectional view of a one-hundred fourth embodiment of the present invention (one-hundred fourth embodiment); 
         FIG. 171  is a block view related to a one-hundred fifth embodiment of the present invention (one-hundred fifth embodiment); 
         FIG. 172  is an expanded system block view of the one-hundred fifth embodiment of  FIG. 171 ; 
         FIG. 173  is a flowchart of the control unit of the mobile telephone in the one-hundred fifth embodiment of  FIG. 171 ; 
         FIG. 174  is a flowchart of the control unit of the headset in the one-hundred fifth embodiment of  FIG. 171 ; 
         FIG. 175  is a block view related to a one-hundred sixth embodiment of the present invention (one-hundred sixth embodiment); 
         FIG. 176  is a schematic view for describing an image of the automatic adjustment of the direction of directivity and the sharpness of the directivity of the microphone in the one-hundred sixth embodiment of  FIG. 175 ; 
         FIG. 177  is a flowchart of the control unit of the mobile telephone in the one-hundred sixth embodiment of  FIG. 175 ; 
         FIG. 178  is a perspective view and cross-sectional view related to a one-hundred seventh embodiment of the present invention (one-hundred seventh embodiment); 
         FIG. 179  is a graph of Fletcher and Munson equal-loudness curves; 
         FIG. 180  is a flowchart of the application processor in the one-hundred seventh embodiment of  FIG. 178 , which calls on  FIG. 87 ; 
         FIG. 181  is a cross-sectional view relating to a one-hundred eighth embodiment and a modification thereof of the present invention (one-hundred eighth embodiment); 
         FIG. 182  is a schematic view of a one-hundred ninth embodiment of the present invention (one-hundred ninth embodiment); 
         FIG. 183  is a schematic view of a one-hundred tenth embodiment of the present invention (one-hundred tenth embodiment); 
         FIG. 184  is a schematic view of a one-hundred eleventh embodiment of the present invention (one-hundred eleventh embodiment); 
         FIG. 185  is a schematic view of a one-hundred twelfth embodiment of the present invention (one-hundred twelfth embodiment); 
         FIG. 186  is a schematic view of a one-hundred thirteenth embodiment of the present invention (one-hundred thirteenth embodiment); 
         FIG. 187  is a schematic view of a one-hundred fourteenth embodiment of the present invention (one-hundred fourteenth embodiment); 
         FIG. 188  is a schematic view of a one-hundred fifteenth embodiment of the present invention (one-hundred fifteenth embodiment); 
         FIG. 189  is a schematic view of a one-hundred sixteenth embodiment of the present invention (one-hundred sixteenth embodiment); 
         FIG. 190  is a schematic view of a one-hundred seventeenth embodiment of the present invention (one-hundred seventeenth embodiment); 
         FIG. 191  is a conceptual perspective view of the one-hundred seventeenth embodiment of  FIG. 190 ; 
         FIG. 192  is a cross-sectional schematic view of a one-hundred eighteenth embodiment of the present invention (one-hundred eighteenth embodiment); 
         FIG. 193  is a schematic view and a block view of a one-hundred nineteenth embodiment of the present invention (one-hundred nineteenth embodiment); 
         FIG. 194  is a schematic view of a one-hundred twentieth embodiment of the present invention (one-hundred twentieth embodiment); 
         FIG. 195  is a schematic view of a one-hundred twenty-first embodiment of the present invention (one-hundred twenty-first embodiment); 
         FIG. 196  is a schematic view of a one-hundred twenty-second embodiment of the present invention (one-hundred twenty-second embodiment); 
         FIG. 197  is a schematic view of a one-hundred twenty-third embodiment of the present invention (one-hundred twenty-third embodiment); 
         FIG. 198  is a schematic view of a one-hundred twenty-fourth embodiment of the present invention (one-hundred twenty-fourth embodiment); 
         FIG. 199  is an enlarged cross-sectional view of the elements and a block view of the one-hundred twenty-fourth embodiment shown in  FIG. 198 ; 
         FIG. 200  is a flowchart of the control unit of the one-hundred twenty-fourth embodiment of  FIG. 199 ; 
         FIG. 201  is an enlarged cross-sectional view of the elements and a block view of the one-hundred twenty-fifth embodiment of the present invention (one-hundred twenty-fifth embodiment); 
         FIG. 202  is an enlarged cross-sectional view of the elements and a block view of the one-hundred twenty-sixth embodiment of the present invention (one-hundred twenty-sixth embodiment); 
         FIG. 203  is an enlarged cross-sectional view of the elements and a block view of the one-hundred twenty-seventh embodiment of the present invention (one-hundred twenty-seventh embodiment); 
         FIG. 204  is a system configuration diagram of a one-hundred twenty-eighth embodiment of the present invention (one-hundred twenty-eighth embodiment); 
         FIG. 205  is a system block diagram of the one-hundred twenty-eighth embodiment shown in  FIG. 204 ; 
         FIG. 206  is a flow chart showing the function of a mobile telephone according to the one-hundred twenty-eighth embodiment; 
         FIG. 207  is a system configuration diagram of a one-hundred twenty-ninth embodiment of the present invention (one-hundred twenty-ninth embodiment); 
         FIG. 208  is a schematic diagram of a one-hundred thirtieth embodiment of the present invention (one-hundred thirtieth embodiment); 
         FIG. 209  is a schematic diagram of a one-hundred thirty-first embodiment of the present invention (one-hundred thirty-first embodiment); 
         FIG. 210  is a schematic diagram of a one-hundred thirty-second embodiment of the present invention (one-hundred thirty-second embodiment); 
         FIG. 211  is a schematic diagram of a one-hundred thirty-third embodiment of the present invention (one-hundred thirty-third embodiment); 
         FIG. 212  is a system configuration diagram of a one-hundred thirty-fourth embodiment of the present invention (one-hundred thirty-fourth embodiment); 
         FIG. 213  is a diagram illustrating a call-conducting posture in the one-hundred thirty-fourth embodiment in  FIG. 212 ; 
         FIG. 214  is a diagram illustrating another call-conducting posture in the one-hundred thirty-fourth embodiment in  FIG. 212 ; 
         FIG. 215  is a system block diagram of the one-hundred thirty-fourth embodiment; 
         FIG. 216  is a flow chart showing the function of a wrist watch-type handset in the one-hundred thirty-fourth embodiment; 
         FIG. 217  is a system configuration diagram of a one-hundred thirty-fifth embodiment of the present invention (one-hundred thirty-fifth embodiment); 
         FIG. 218  is an enlarged front view of an ID name tag-type handset of the one-hundred thirty-fifth embodiment; 
         FIG. 219  is an enlarged front view of an ID name tag-type handset of the one-hundred thirty-fifth embodiment, in a different display state; 
         FIG. 220  is a system block diagram of the one-hundred thirty-fifth embodiment; 
         FIG. 221  is a flow chart of a control unit in an ID name tag-type handset of the one-hundred thirty-fifth embodiment; 
         FIG. 222  comprises a perspective view and sectional views of a one-hundred thirty-sixth embodiment of the present invention (one-hundred thirty-sixth embodiment); 
         FIG. 223  comprises sectional views of a one-hundred thirty-seventh embodiment of the present invention and a modified example thereof (one-hundred thirty-seventh embodiment); 
         FIG. 224  comprises a perspective view and sectional views of a one-hundred thirty-eighth embodiment of the present invention (one-hundred thirty-eighth embodiment); 
         FIG. 225  comprises a perspective view and sectional views of a one-hundred thirty-ninth embodiment of the present invention (one-hundred thirty-ninth embodiment); 
         FIG. 226  comprises a perspective view and sectional views of a one-hundred fortieth embodiment of the present invention (one-hundred fortieth embodiment); 
         FIG. 227  comprises a perspective view and sectional views of a one-hundred forty-first embodiment of the present invention (one-hundred forty-first embodiment); 
         FIG. 228  comprises a perspective view and sectional views of a one-hundred forty-second embodiment of the present invention (one-hundred forty-second embodiment); 
         FIG. 229  comprises a perspective view and sectional views of a one-hundred forty-third embodiment of the present invention (one-hundred forty-third embodiment); 
         FIG. 230  is a schematic diagram of a one-hundred forty-fourth embodiment of the present invention (one-hundred forty-fourth embodiment); 
         FIG. 231  comprises a perspective view, sectional views, a top view, and a side view of a one-hundred forty-fifth embodiment of the present invention (one-hundred forty-fifth embodiment); 
         FIG. 232  comprises a perspective view and top views of a one-hundred forty-sixth embodiment of the present invention (one-hundred forty-sixth embodiment); 
         FIG. 233  is a block diagram of a one-hundred forty-seventh embodiment of the present invention (one-hundred forty-seventh embodiment); 
         FIG. 234  is a flow chart of an application processor in the one-hundred forty-seventh embodiment; 
         FIG. 235  comprises a perspective view and top views of a one-hundred forty-eighth embodiment of the present invention (one-hundred forty-eighth embodiment); 
         FIG. 236  comprises a perspective view, sectional views, a top view, and a side view of a one-hundred forty-ninth embodiment of the present invention (one-hundred forty-ninth embodiment); 
         FIG. 237  comprises schematic diagrams of a side face of an ear and a top face of a head during use of the one-hundred forty-ninth embodiment in  FIG. 236 ; 
         FIG. 238  comprises perspective views showing examples of explanations of methods for using a mobile telephone in the one-hundred forty-ninth embodiment shown in  FIG. 237 ; 
         FIG. 239  comprises a perspective view, sectional views, and a top view showing a one-hundred fiftieth embodiment of the present invention (one-hundred fiftieth embodiment); 
         FIG. 240  is a block diagram related to a one-hundred fifty-first embodiment of the present invention (one-hundred fifty-first embodiment); 
         FIG. 241  is a flow chart of the operation of a control unit in the one-hundred fifty-first embodiment in  FIG. 240 ; 
         FIG. 242  comprises a perspective view and sectional views related to a one-hundred fifty-second embodiment of the present invention (one-hundred fifty-second embodiment); 
         FIG. 243  comprises a perspective view and sectional views related to a one-hundred fifty-third embodiment of the present invention (one-hundred fifty-third embodiment); 
         FIG. 244  comprises a perspective view and sectional views related to a one-hundred fifty-fourth embodiment of the present invention (one-hundred fifty-fourth embodiment); 
         FIG. 245  comprises a perspective view and sectional views related to a one-hundred fifty-fifth embodiment of the present invention (one-hundred fifty-fifth embodiment); 
         FIG. 246  is a partly enlarged detailed sectional view of  FIG. 245C  related to the one-hundred fifty-fifth embodiment 
         FIG. 247  comprises a perspective view and sectional views related to a one-hundred fifty-sixth embodiment of the present invention (one-hundred fifty-sixth embodiment); 
         FIG. 248  comprises a perspective view and sectional views related to a one-hundred fifty-seventh embodiment of the present invention (one-hundred fifty-seventh embodiment); 
         FIG. 249  comprises a perspective view and sectional views related to a one-hundred fifty-eighth embodiment of the present invention (one-hundred fifty-eighth embodiment); 
         FIG. 250  comprises a perspective view and sectional views related to a one-hundred fifty-ninth embodiment of the present invention (one-hundred fifty-ninth embodiment); 
         FIG. 251  is a front view of a one-hundred sixtieth embodiment of the present invention (one-hundred sixtieth embodiment); 
         FIG. 252  is an overall block diagram of the one-hundred sixtieth embodiment in  FIG. 251 ; 
         FIG. 253  is a front view of a one-hundred sixty-first embodiment of the present invention (one-hundred sixty-first embodiment); 
         FIG. 254  is an overall block diagram of the one-hundred sixty-first embodiment in  FIG. 253 ; 
         FIG. 255  is a system block diagram of a one-hundred sixty-second embodiment of the present invention (one-hundred sixty-second embodiment); 
         FIG. 256  comprises front views of modified examples of the one-hundred sixtieth to sixty-second embodiments in  FIGS. 251 to 255 ; 
         FIG. 257  comprises a perspective view and a sectional view of a one-hundred sixty-third embodiment of the present invention (one-hundred sixty-third embodiment); 
         FIG. 258  comprises a perspective view and a sectional view of a one-hundred sixty-fourth embodiment of the present invention (one-hundred sixty-fourth embodiment); 
         FIG. 259  comprises a perspective view and a sectional view of a one-hundred sixty-fifth embodiment of the present invention (one-hundred sixty-fifth embodiment); 
         FIG. 260  comprises a perspective view and a sectional view of a one-hundred sixty-sixth embodiment of the present invention (one-hundred sixty-sixth embodiment); 
         FIG. 261  comprises a perspective view and a sectional view of a one-hundred sixty-seventh embodiment of the present invention (one-hundred sixty-seventh embodiment); 
         FIG. 262  comprises front sectional views of a one-hundred sixty-eighth embodiment according to the present invention (one-hundred sixty-eighth embodiment); 
         FIG. 263  comprises front sectional views of a one-hundred sixty-ninth embodiment according to the present invention (one-hundred sixty-ninth embodiment); 
         FIG. 264  comprises a sectional view of a one-hundred seventieth embodiment of the present invention and diagrams illustrating how it is worn on an ear (one-hundred seventieth embodiment); 
         FIG. 265  is a block diagram of the one-hundred seventieth embodiment; 
         FIG. 266  is a block diagram showing the details of a sound processing unit in the one-hundred seventieth embodiment; 
         FIG. 267  is a basic flow chart related to the operation of a headset control unit in the one-hundred seventieth embodiment; 
         FIG. 268  is a flow chart showing the details of step S 1112  in  FIG. 267 ; 
         FIG. 269  is a flow chart showing the details of step S 1114  in  FIG. 267 ; 
         FIG. 270  is a side view related to a one-hundred seventy-first embodiment of the present invention (one-hundred seventy-first embodiment); 
         FIG. 271  is an overall block diagram of a bicycle helmet in the one-hundred seventy-first embodiment; 
         FIG. 272  is a system concept diagram showing the bicycle helmet of the one-hundred seventy-first embodiment along with a power-assisted bicycle; 
         FIG. 273  is a system block diagram corresponding to the one-hundred seventy-first embodiment in  FIG. 272 ; 
         FIG. 274  is a side view of a modified example of the one-hundred seventy-first embodiment; 
         FIG. 275  comprises cross-sectional views of a principal part related to a one-hundred seventy-second embodiment of the present invention (one-hundred seventy-second embodiment); 
         FIG. 276  is a system block diagram showing the one-hundred seventy-second embodiment along with a mobile telephone combined with it; 
         FIG. 277  is a table summarizing different operation conditions in the one-hundred seventy-second embodiment; 
         FIG. 278  is a basic flow chart related to the operation of the one-hundred seventy-second embodiment; 
         FIG. 279  is a flow chart showing the details of step S 1208  in  FIG. 276 ; 
         FIG. 280  comprises cross-sectional views of a principal part of a one-hundred seventy-third embodiment of the present invention (one-hundred seventy-third embodiment); 
         FIG. 281  comprises schematic diagrams of a one-hundred seventy-fourth embodiment of the present invention (one-hundred seventy-fourth embodiment); 
         FIG. 282  is a block diagram of the one-hundred seventy-fourth embodiment in  FIG. 281 ; 
         FIG. 283  comprises schematic diagrams of a one-hundred seventy-fifth embodiment of the present invention (one-hundred seventy-fifth embodiment); 
         FIG. 284  comprises schematic diagrams of a one-hundred seventy-sixth embodiment of the present invention (one-hundred seventy-sixth embodiment); 
         FIG. 285  comprises schematic diagrams of a one-hundred seventy-seventh embodiment of the present invention (one-hundred seventy-seventh embodiment); 
         FIG. 286  comprises schematic diagrams of a one-hundred seventy-eighth embodiment of the present invention (one-hundred seventy-eighth embodiment); 
         FIG. 287  comprises schematic diagrams of a one-hundred seventy-ninth embodiment of the present invention (one-hundred seventy-ninth embodiment); 
         FIG. 288  is a block diagram of the one-hundred seventy-ninth embodiment in  FIG. 287 ; 
         FIG. 289  comprises front views of a one-hundred eightieth embodiment of the present invention and a modified example of it (one-hundred eightieth embodiment); 
         FIG. 290  is a perspective view showing how an air-conduction speaker module is used in a one-hundred eighty-first embodiment of the present invention (one-hundred eighty-first embodiment); 
         FIG. 291  is a perspective view showing how a cartilage conduction module is used in the one-hundred eighty-first embodiment; 
         FIG. 292  comprises perspective views illustrating how the cartilage conduction module is inserted in a slot in the one-hundred eighty-first embodiment; 
         FIG. 293  is a block diagram of the one-hundred eighty-first embodiment; 
         FIG. 294  comprises perspective views of a one-hundred eighty-second embodiment of the present invention (one-hundred eighty-second embodiment); 
         FIG. 295  is a block diagram of the one-hundred eighty-second embodiment; 
         FIG. 296  comprises perspective views of a one-hundred eighty-third embodiment of the present invention (one-hundred eighty-third embodiment); 
         FIG. 297  comprises perspective views of a one-hundred eighty-fourth embodiment of the present invention (one-hundred eighty-fourth embodiment); 
         FIG. 298  comprises a perspective view and cross-sectional views of a one-hundred eighty-fifth embodiment of the present invention (one-hundred eighty-fifth embodiment); 
         FIG. 299  is a front view of a one-hundred eighty-sixth embodiment of the present invention (one-hundred eighty-sixth embodiment); 
         FIG. 300  is a cross-sectional view of the one-hundred eighty-sixth embodiment; 
         FIG. 301  is a block diagram of a mobile telephone in the one-hundred eighty-sixth embodiment; 
         FIG. 302  is a flow chart of a control unit in the mobile telephone in the one-hundred eighty-sixth embodiment; 
         FIG. 303  is a block diagram of a hearing aid in the one-hundred eighty-sixth embodiment; 
         FIG. 304  is a flow chart of a control unit in the hearing aid in the one-hundred eighty-sixth embodiment; and 
         FIG. 305  is a front view related to a one-hundred eighty-seventh embodiment (one-hundred eighty-seventh embodiment). 
     
    
    
     SOLUTION TO PROBLEM 
     First Embodiment 
       FIG. 1  is a perspective view illustrating a first embodiment of the mobile telephone according to an aspect of the present invention. In  FIG. 1 , a mobile telephone  1  comprises an upper part  7  having a display unit  5  or the like, and a lower part  11  having a keypad or other operation unit  9  and a microphone or other outgoing-talk unit  23  for picking up audio uttered from the mouth of an operator, and is configured such that the upper part  7  can be folded onto the lower part  11  by a hinge unit  3 . An earphone or other incoming-talk unit  13  for transmitting audio to an ear of the operator is provided to the upper unit  7 , and together with the outgoing-talk unit  23  of the lower part  11  constitutes a telephone function unit. A videoconferencing in-camera  17 , which is able to photograph the face of an operator looking at the display unit  5  in a case in which the mobile telephone  1  is to be used as a video phone and which is also used when a self-portrait is taken, is also arranged on the upper part  7 . The upper part  7  is further provided with a pair of infrared light emitting units  19 ,  20  constituting a proximity sensor for detecting that the mobile telephone  1  is abutting an ear for purposes of a call, and with a shared infrared light proximity sensor  21  for receiving infrared light reflected from the ear. Although not shown in  FIG. 1 , a backside camera is provided to the backside of the upper part  7 , and the camera is able to capture an image of a subject that is on the backside of the mobile telephone  1  and is being monitored with the display unit  5 . 
     The upper part  7  is further provided with a right-ear cartilage-conduction vibration unit  24  and a left-ear cartilage-conduction vibration unit  26 , which comprise a piezoelectric bimorph element or the like for contacting the tragus, at the upper corner of the inside (the side that touches the ear). The right-ear cartilage-conduction vibration unit  24  and the left-ear cartilage-conduction vibration unit  26  are constituted so as not to protrude from the outer wall of the mobile telephone and hinder the design, but are provided to the corners of the outer wall of the mobile telephone whereby contact is effectively made with the tragus. It is thereby possible both to listen to the audio from the incoming-talk unit  13 , and to listen by bone conduction from the cartilage of the tragus. Also, as has been disclosed in the above-mentioned Patent Document 2, the tragus is known to receive the greatest auditory sensation among the mastoid process of the ear, the cartilage surface of the rear of the opening of the outer ear, the tragus, the sideburn part, and all the other constituents of the ear cartilage; and is known to have a greater elevation in the bass register than other locations when pressure is increased by pushing. This knowledge is described in detail in Patent Document 2, for which reference can accordingly be made thereto. 
     The mobile telephone  1  rotates slightly clockwise when brought up against the right ear in  FIG. 1 , and takes on a downward-right state in  FIG. 1 . Providing the right-ear cartilage-conduction vibration unit  24  to the lower angle of incline of the upper end of the ear side of such a mobile telephone makes it possible to naturally bring the right-ear cartilage-conduction vibration unit  24  in contact with the tragus of the right ear without causing the vibration unit to protrude from the outer wall of the mobile telephone. This state is a posture approximating the normal state of a telephone call, and is awkward for neither the person making the telephone call nor any onlookers. Because the incoming-talk unit  13  is in the vicinity of the right-ear cartilage-conduction vibration unit  24 , audio information through the tragus cartilage and audio information through the external auditory meatus will both be transmitted to the ear. At this time, because the same audio information will be transmitted by different sound-generating pairs and pathways, the phasing between the two is adjusted so as to prevent the same from canceling each other out. 
     On the other hand, the mobile telephone  1  rotates slightly counter-clockwise when brought up against the left ear in  FIG. 1 , and takes on a downward-left state in  FIG. 1 . The state becoming such that the left-ear cartilage-conduction vibration unit  26  is provided to the lower angle of incline of the upper end of the ear side of the mobile telephone, it is possible to naturally bring the left-ear cartilage-conduction vibration unit  26  into contact with the tragus of the left ear, as is the case with the right ear. Because this state is a posture approximating the normal state of a telephone call, and because the incoming-talk unit  13  is in the vicinity of the left-ear cartilage-conduction vibration unit  26  and both audio information through the tragus cartilage and audio information through the external auditory meatus are transmitted to the ear, the fact that the phasing between the two is adjusted is similar to the case of the right ear. 
     Because the pair of infrared light emitting units  19 ,  20  in the above-described proximity sensor emit light alternating in time division, the shared infrared light proximity sensor  21  is able to identify from which light-emitting unit the reflective light coming from the infrared light has been received, and is thereby able to judge which of the right-ear cartilage-conduction vibration unit  24  and the left-ear cartilage-conduction vibration unit  26  has been brought up against the tragus. It is thereby possible to determine at which ear the mobile telephone  1  is being used, and to cause the vibration unit of the side against which the tragus abuts to vibrate and to turn off the other one. However, because of the individual variations regarding up to which ear the mobile telephone  1  is brought and regarding the shape of the ear, the first embodiment is configured such that, as will be described later, an acceleration sensor is further housed, the direction in which the mobile telephone  1  is inclined being detected by the gravitational acceleration detected by the acceleration sensor, and the vibration unit on the side at the lower angle of incline is made to vibrate while the other is turned off. The aforementioned right ear use and left ear use will again be described, using the drawings adapted to the respective modes of use. 
     The upper part  7  is further provided with an environment-noise microphone  38 , which is arranged on the outside (the back surface not brought up against the ear) so as to pick up environment noise, and which is implemented as means for preventing conduction of the vibration of the right-ear cartilage-conduction vibration unit  24  and the left-ear cartilage-conduction vibration unit  26 . The environment-noise microphone  38  further picks up audio uttered from the mouth of the operator. The environment noise picked up by the environment-noise microphone  38  and the operator&#39;s own voice, upon undergoing wavelength inversion, are mixed into the right-ear cartilage-conduction vibration unit  24  and the left-ear cartilage-conduction vibration unit  26 ; the environment noise and the operator&#39;s own voice, which are contained in the audio information through the incoming-talk unit  13 , are canceled to facilitate listening comprehension of the party on the line. A more detailed description of this function will be provided later. 
       FIG. 2  is a side view of the mobile telephone  1  illustrating the functions of the right-ear cartilage-conduction vibration unit  24  and left-ear cartilage-conduction vibration unit  26 ;  FIG. 2A  illustrates a state in which the mobile telephone  1  is held in the right hand and brought up against the right ear  28 . On the other hand,  FIG. 2B  illustrates a state in which the mobile telephone  1  is held in the left hand and brought up against the left ear  30 .  FIG. 2A  is a drawing viewed from the right side of the face, and  FIG. 2B  is a drawing viewed from the left side of the face; therefore, each show the back surface of the mobile telephone  1  (the reverse side of  FIG. 1 ). The mobile telephone  1  is indicated by dashed lines, in order to depict the relationship between the mobile telephone  1  and the right ear  28  and left ear  30 . 
     As illustrated in  FIG. 2A , the mobile telephone  1  is inclined slightly counterclockwise (the relationship of the reverse surface with  FIG. 1 ) in  FIG. 2  when the same is brought up against the right ear  28 , and takes on a diagonally downward-left state in  FIG. 2 . Because the right-ear cartilage-conduction vibration unit  24  is provided to the lower angle of incline of the upper end of the ear side of such a mobile telephone, the same can naturally be brought into contact with the tragus  32  of the right ear  28 . As has already been described, this state is a posture approximating the normal state of a telephone call, and is awkward neither to the person making the telephone call nor to onlookers. On the other hand, as illustrated in  FIG. 2B , the mobile telephone  1  is inclined slightly clockwise (the relationship of the reverse side with  FIG. 1 ) in  FIG. 2  when the same is brought up against the left ear  30 , and takes on a diagonally downward-right state in  FIG. 2 . Because the left-ear cartilage-conduction vibration unit  26  is provided to the lower angle of incline of the upper end of the ear side of such a mobile telephone, the same can naturally be brought into contact with the tragus  34  of the left ear  30 . This state as well, as is the case with the right ear  28 , is a posture approximating the normal state of a telephone call, and is awkward neither to the person making the telephone call nor to onlookers. 
       FIG. 3  is a block diagram of the first embodiment, the same portions being given the same reference numerals as in  FIG. 1 , and a description having been omitted unless necessary. The mobile telephone  1  is controlled by a controller  39 , which operates in accordance with a program stored in a memory unit  37 . The memory unit  37  is further able to temporarily store data needed for the control of the controller  39  and also to store various measurement data and/or images. The display unit  5  displays on the basis of the control of the controller  39  and on the basis of display data held by a display driver  41 . The display unit  5  has a display backlight  43 , the controller  39  adjusting the brightness thereof on the basis of the brightness of the surroundings. 
     A telephone function unit  45 , which includes the incoming-talk unit  13  and the outgoing-talk unit  23 , is capable of connecting with a wireless telephone line using a telephone communication unit  47 , which is under the control of the controller  39 . A speaker  51  provides ring alerts and various types of guidance by the control of the controller  39 , and also outputs the other party&#39;s voice during a videoconferencing function. The audio output of the speaker  51  is not to be outputted from the right-ear cartilage-conduction vibration unit  24  and the left-ear cartilage-conduction vibration unit  26 , because it is not possible to bring a cartilage conduction vibration unit up against the ear during a videoconferencing function. An image processing unit  53  is controlled with the controller  39  and processes an image photographed by a videoconferencing function in-camera  17  and a backside main camera  55 , and inputs the image resulting from the processing into the memory unit  37 . 
     As described above, the pair of infrared light emitting units  19 ,  20  in the proximity sensor emit light alternating in time division on the basis of the control of the controller  39 . Accordingly, the reflected infrared light inputted into the controller  39  by the shared infrared light proximity sensor  21  allows for identification of reflected light by the infrared light from either light-emitting unit. When reflected light is detected from both the infrared light emitting units  19 ,  20 , the controller  39  runs a cross comparison to determine which of the right-ear cartilage-conduction vibration unit  24  and left-ear cartilage-conduction vibration unit  26  has been brought up against the tragus. Further, the acceleration sensor  49  detects the orientation of the detected gravitational acceleration. The controller  39  determines, on the basis of the detection signal, whether the mobile telephone  1  is inclined in the state of  FIG. 2A  or  FIG. 2B ; as has been described with  FIG. 2 , the vibration unit on the side at the lower angle of incline is made to vibrate and the other is turned off. 
     The mobile telephone  1  further possesses a phase adjustment mixer unit  36  for running phase adjustment for the audio information from the controller  39  and for transmitting to the right-ear cartilage-conduction vibration unit  24  and left-ear cartilage-conduction vibration unit  26 . More specifically, the phase adjustment mixer unit  36  uses the audio information transmitted to the incoming-talk unit  13  from the controller  39  as a benchmark to run phase adjustment for the audio information from the controller  39  and transmits to the right-ear cartilage-conduction vibration unit  24  and left-ear cartilage-conduction vibration unit  26 , in order to prevent the mutual canceling out of the audio information generated from the incoming-talk unit  13  and transmitted via the tympanic membrane from the external auditory meatus and of the same audio information generated from either the right-ear cartilage-conduction vibration unit  24  or left-ear cartilage-conduction vibration unit  26  and transmitted via the cartilage of the tragus. The phase adjustment is a relative adjustment between the incoming-talk unit  13  and the right-ear cartilage-conduction vibration unit  24  and left-ear cartilage-conduction vibration unit  26 , and therefore the configuration may be such that the audio information transmitted from the controller  39  to the right-ear cartilage-conduction vibration unit  24  and left-ear cartilage-conduction vibration unit  26  is used as a benchmark for adjusting the phase of the audio information transmitted from the controller  39  to the incoming-talk unit  13 . In this case, the audio information to the speaker  51  is also adjusted in the same phase as the audio information to the incoming-talk unit  13 . 
     In addition to having the first function described above of preventing the mutual canceling out of the audio information from the incoming-talk unit  13  and the identical audio information from the right-ear cartilage-conduction vibration unit  24  or the left-ear cartilage-conduction vibration unit  26 , the phase adjustment mixer unit  36  also has a second function through collaboration with the environment-noise microphone  38 . In this second function, the environment noise picked up by the environment-noise microphone  38  and the operator&#39;s own voice, upon undergoing wavelength inversion by the phase adjustment mixer unit  36 , are mixed into the audio information of the right-ear cartilage-conduction vibration unit  24  or the left-ear cartilage-conduction vibration unit  26 ; the environment noise and the operator&#39;s own voice, which are contained in the audio information through the incoming-talk unit  13 , are thereby canceled to facilitate listening comprehension of the audio information of the party on the line. At this time, the mixing is done also taking into consideration the phase adjustment that is based on the first function, so as to effectively cancel out the environment noise and the operator&#39;s own voice regardless of the different transmission routes of the audio information from the incoming-talk unit  13  and the audio information from either the right-ear cartilage-conduction vibration unit  24  or the left-ear cartilage-conduction vibration unit  26 . 
       FIG. 4  is a flowchart of the operation of the controller  39  in the first embodiment of  FIG. 2 . To provide a description primarily of the function of the right-ear cartilage-conduction vibration unit  24  and the left-ear cartilage-conduction vibration unit  26 , the flow of  FIG. 4  illustrates an abstraction of the operation, focusing on related functions; the controller  39  also contains typical mobile telephone functions and other operations not represented in the flow of  FIG. 4 . The flow of  FIG. 4  begins when a main power source is turned on by the operation unit  9  of the mobile telephone  1 ; and in step S 2  an initial startup and a check of each unit function are performed and a screen display on the display unit  5  is started. Next, in step S 4 , the functions of the right-ear cartilage-conduction vibration unit  24  and left-ear cartilage-conduction vibration unit  26  are turned off to proceed on to step S 6 . Step S 6  is a check of the presence or absence of an e-mail operation and/or Internet operation, as well as other operations in which radio operations are not used, such as various settings and also downloaded games (which hereinafter are collectively referred as “non-call operations”). In the case of these operations, execution proceeds on to step S 8  for non-call processing, and then arrives at step S 10 . However, the function in non-call operations is not assumed to be a function of the incoming-talk unit  13  and/or the right-ear cartilage-conduction vibration unit  24  and left-ear cartilage-conduction vibration unit  26  in the upper part  7  of the mobile telephone  1  that is performed brought up against the ear. On the other hand, step S 6  proceeds directly on to step S 10  when no non-call operations are detected. 
     In step S 10 , there is performed a check for whether or not there is an incoming call by mobile radio waves. A case of no incoming call proceeds on to step S 12 ; there is performed a check for whether or not there has been a response from the other party to a call request from the mobile telephone  1 . A case in which a response is detected proceeds on to step S 14 . On the other hand, a case in which it is detected by mobile radio waves in step S 10  that there is an incoming call moves on to step S 16 , in which there is performed a check for whether the mobile telephone  1  is open; i.e., a check for whether the upper part  7  has gone from a state of being folded over the lower part  11  to an opened state as in  FIG. 1 . A case in which it is not possible to detect that the mobile telephone  1  is open returns to step S 10 ; thereafter, step S 10  and step S 16  are repeated and the flow pauses for the mobile telephone  1  to be open. However, when, during this repetition, the incoming call is terminated while the mobile telephone  1  remains unopened, the flow moves from step S 10  to step S 12 . On the other hand, a case in which it has been detected in step S 16  that the mobile telephone  1  is open proceeds to step S 14 . In step S 14 , the outgoing-talk unit  23  and the incoming-talk unit  13  are turned on to move on to step S 18 . In step S 18 , there is a check whether or not the call is a videoconferencing function, the flow moving on to step S 20  when the call is not a videoconferencing function; at this point in time, there is a confirmation of whether or not the call is cut off, the flow moving on to step S 22  when the call is not cut off. 
     In step S 22 , there is performed a check for whether or not the infrared light proximity sensor  21  detects contact with an ear, and the flow proceeds to step S 24  when no contact is detected. On the other hand, in step S 22  the flow returns to step S 14  when the infrared light proximity sensor  21  does not detect contact with an ear; as follows, step S 14  and from step S 18  to S 22  are repeated and detection by the proximity sensor in step S 22  is awaited. In step S 24 , there is performed a check for whether an incline of the right ear call state has occurred as illustrated in  FIG. 2A , on the basis of the detection signal of the acceleration sensor  49 . In a case in which this is true, the flow proceeds to step S 26 ; the right-ear cartilage-conduction vibration unit  24  is turned on, and the flow moves on to step S 28 . On the other hand, in a case in which it cannot be detected in step S 24  that the incline of the right ear call state has occurred, the flow proceeds on to step S 30  after the detection signal of the acceleration sensor  49  signifies that the left ear call state as illustrated in  FIG. 2B  has been detected; the left-ear cartilage-conduction vibration unit  26  is turned on, and the flow moves on to step S 28 . 
     In the above description of  FIG. 4 , the flow is described as proceeding on to step S 24  regardless of whether the infrared reflected light detected by the infrared light proximity sensor  21  comes from the infrared light emitting unit  19  or  20 , and in step S 24  the signal of the acceleration sensor  49  is used to detect whether or not the incline is in the right ear call state. However, because the infrared light proximity sensor  21  can also be used to detect whether or not the incline is in the right ear call state, the configuration may be such that, instead of the signal of the acceleration sensor  49  in step S 24 , the incline is judged to be in the right ear call state when the output of the infrared light proximity sensor  21  in the light-emitting timing of the infrared light emitting unit  19  is greater than that in the light-emitting timing of the infrared light emitting unit  20 . Also, the configuration in step S 24  may be such that the judgment of whether or not the incline is in the right ear call state is made together with the signal of the acceleration sensor  49  and the results of a comparison of the outputs of the infrared light proximity sensor  21  in the light-emitting timings of the infrared light emitting units  19 ,  20 . 
     In step S 28 , there is performed a check for whether or not the call state has been cut off, the flow returning to step S 24  when the call has not been cut off; as follows, step S 24  to step S 30  are repeated until a call interruption is detected in step S 28 . Support is thereby provided for switching the hand holding the mobile telephone  1  during a call, between the right ear call state and the left ear call state. On the other hand, in a case in which a call interruption is detected in step S 28 , the flow moves on to step S 32 , in which either the right-ear cartilage-conduction vibration unit  24  or the left-ear cartilage-conduction vibration unit  26  that is in an on state, as well as the incoming-talk unit  13  and the outgoing-talk unit  23 , are turned on, and the flow then moves on to step S 34 . On the other hand, in a case in which a call request response has been detected in step S 12 , the flow moves directly on to step S 34 . In a case in which there is detected to be a videoconferencing function in step S 18 , the flow moves on to the videoconferencing function processing of step S 36 . The videoconferencing function processing involves imaging one&#39;s face using the videoconferencing function in-camera  17 , outputting the voice of the other party using the speaker  51 , switching the sensitivity of the outgoing-talk unit  23 , displaying the face of the other party on the display unit  5 , or the like. Once such videoconferencing function processing has concluded, the flow proceeds to step S 38 , which turns off the speaker  51 , the incoming-talk unit  13 , and the outgoing-talk unit  23 , whereupon the flow moves on to step S 34 . In a case in which a call interruption is detected in step S 20 , the flow also moves on to step S 38 , but since the speaker  51  is not originally turned on at that time, the incoming-talk unit  13  and the outgoing-talk unit  23  are turned off and the flow moves on to step S 34 . 
     In step S 34 , there is a check for the presence or absence of an operation to turn off the primary power source; the flow is terminated when there is a turning-off operation. On the other hand, when there is no detection of an operation to turn off the primary power source in step S 34 , the flow returns to step S 6 , whereupon steps S 6  to step S 38  are repeated. As described above, the right-ear cartilage-conduction vibration unit  24  or the left-ear cartilage-conduction vibration unit  26  will not be turned on when the mobile telephone  1  is not open, when the mobile telephone  1  is not in the call state, when the call state is enabled but is a videoconferencing function, or when an ordinary call state is enabled but the mobile telephone  1  is not brought up against the ear. Once the right-ear cartilage-conduction vibration unit  24  or the left-ear cartilage-conduction vibration unit  26  is in the on state, then as long as a call interruption is not detected, it will not be turned off except when on/off switching of the right-ear cartilage-conduction vibration unit  24  or the left-ear cartilage-conduction vibration unit  26  is performed. 
     Second Embodiment 
       FIG. 5  is a perspective view depicting a second embodiment of the mobile telephone according to an aspect of the present invention. Structurally there is much in common in the second embodiment, and so corresponding portions have been given like reference numerals as in the first embodiment, and a description has been omitted. The mobile telephone  101  of the second embodiment has an integrated type with no movable parts, rather than a folding one separated into an upper part and a bottom part. Accordingly, the “upper part” in such a case does not signify a separated upper part but rather signifies the portion at the top of the integrated structure. 
     In the second embodiment, the right-ear cartilage-conduction vibration unit  24  and the left-ear cartilage-conduction vibration unit  26  assume a form of being constantly exposed on the outer wall of the mobile telephone  101 , whereas in the first embodiment, the right-ear cartilage-conduction vibration unit  24  and the left-ear cartilage-conduction vibration unit  26  assume a form of being housed while sandwiched between the upper part  7  and the lower part  11  when the mobile telephone  1  is folded shut. The essential points of the internal structure of  FIG. 3  and the flowchart of  FIG. 4  can be applied to the second embodiment as well. Regarding the above-described structural differences, step S 16  of the flowchart of  FIG. 4  is left out; in a case in which an incoming telephone call is confirmed in step S 10 , the flow moves directly on to step S 14 . 
     Third Embodiment 
       FIG. 6  is a perspective view illustrating a third embodiment of the mobile telephone according to an aspect of the present invention. Structurally there is much in common in the third embodiment, and so corresponding portions have been given like reference numerals as in the first embodiment, and a description has been omitted. The mobile telephone  201  of the third embodiment has a structure in which the upper part  107  is able to slide relative to the lower part  111 . In the structure of the third embodiment, the up-down relationship is lost in the state in which the upper part  107  is placed on top of the lower part  111 , but the “upper part” in the third embodiment signifies the portion that comes up when the mobile telephone  201  is extended. 
     In the third embodiment, full functionality is available in the state in which, as illustrated in  FIG. 6 , the upper part  107  is extended to expose the operation unit  9 , and also basic functionality, such as responding to incoming calls and/or participating in a call, is also available in a case in which the upper part  107  is placed on top of the lower part  111  and the operation unit  9  is concealed. In the third embodiment as well, the right-ear cartilage-conduction vibration unit  24  and the left-ear cartilage-conduction vibration unit  26  assume a form of being constantly exposed on the outer wall of the mobile telephone  201  in both the state in which, as illustrated in  FIG. 6 , the mobile telephone  201  is extended, and the state in which the upper part  107  is placed on top of the lower part  111 . The essential points of the internal structure of  FIG. 3  and the flowchart of  FIG. 4  can be applied to the third embodiment as well. However, as described above, the third embodiment allows calls to take place even when the upper part  107  is placed on top of the lower part  111 , and therefore, similarly with respect to the second embodiment, step S 16  of the flowchart in  FIG. 4  is left out; in a case in which an incoming call is confirmed in step S 10  the flow moves directly on to step S 14 . 
     The implementation of the variety of features of the present invention as described above is not to be limited to the above embodiments; they can be implemented in other aspects as well. For example, because the above embodiments support both right ear usage and left ear usage from changing hands and/or changing users, although the right-ear cartilage-conduction vibration unit  24  and the left-ear cartilage-conduction vibration unit  26  have been provided, the cartilage conduction vibration unit may be singular in a case that assumes usage of only the right ear or of only the left ear for cartilage conduction. 
     Also, although the right-ear cartilage-conduction vibration unit  24  and the left-ear cartilage-conduction vibration unit  26  have originally been provided with the assumption that each would abut the tragus of the right ear and the tragus of the left ear, respectively, cartilage conduction is also possible in an ear cartilage constituent other than the tragus, such as the mastoid process or the cartilage surface of the rear of the opening of the outer ear, as has been disclosed in Patent Document 2; therefore, both the right-ear cartilage-conduction vibration unit  24  and the left-ear cartilage-conduction vibration unit  26  may be used when, for example, the right ear is used, by simultaneously pushing against appropriate points on the right ear cartilage. In this sense, the two cartilage conduction vibration units  24 ,  26  need not be limited to right ear usage and left ear usage. Both are turned on at the same time in such a case, instead of only turning on either one of the two cartilage conduction vibration units  24 ,  26 , as in the embodiments. 
     Further, although the incoming-talk unit  13  and the right-ear cartilage-conduction vibration unit  24  and left-ear cartilage-conduction vibration unit  26  are to be turned on at the same time in the embodiments above, the configuration may be such that the incoming-talk unit  13  is to be turned off when either the right-ear cartilage-conduction vibration unit  24  or the left ear cartilage conduction unit  26  is turned on. In such a case, there is no longer a need for phase adjustment of the audio information. 
     Fourth Embodiment 
       FIG. 7  is a perspective view illustrating a fourth embodiment of the mobile telephone according to an aspect of the present invention. Structurally there is much in common in the fourth embodiment; therefore, corresponding portions have been given like reference numerals as in the first embodiment, and a description has been omitted. A mobile telephone  301  of the fourth embodiment has an integrated type with no movable parts, rather than a folding one separated into an upper part and a bottom part, similarly with respect to the second embodiment. Also, this embodiment is configured as a “smartphone,” which has a large-screen display unit  205  provided with graphical user interface (GUI) functionality. In the fourth embodiment as well, “upper part” does not signify a separated upper part but rather signifies the portion at the top of the integrated structure. However, in the fourth embodiment, a keypad or other operation unit  209  is displayed on the large-screen display unit  205 , and the GUI is operated in accordance with how a finger is touched and/or swiped relative to the large-screen display unit  205 . 
     The cartilage conduction vibration functionality in the fourth embodiment is assigned to a cartilage conduction vibration unit, which has a vibration conductor  227  and a cartilage conduction vibration source  225 , comprising a piezoelectric bimorph or the like. The cartilage conduction vibration source  225  is arranged to be in contact with the lower part of the vibration conductor  227 , the vibration thereof being conducted to the vibration conductor  227 . The cartilage conduction vibration source  225  is constituted so as not to protrude from the outer wall of the mobile telephone (front view shown in  FIG. 7 ) and hinder the design, similarly with respect to the first to third embodiments, but the vibration of the cartilage conduction vibration source  225  is transmitted laterally by the vibration conductor  227 , causing the two ends  224  and  226  thereof to vibrate. The two ends  224  and  226  of the vibration conductor  227  are located on the inner angle of the top part  7  of the mobile telephone  301 , which is in contact with the tragus, and therefore, similarly with respect to the first to third embodiments, effectively come into contact with the tragus without protruding from the outer wall of the mobile telephone. Thus, the right end part  224  and left end part  226  of the vibration conductor  227  respectively constitute the right-ear cartilage-conduction vibration unit  24  and left-ear cartilage-conduction vibration unit  26  mentioned in the first embodiment. However, because the vibration conductor  227  does not vibrate only at the right end  224  and left end  226  thereof but vibrates as a whole, it is possible in the fourth embodiment to transmit audio information regardless of where on the top inner edge of the mobile telephone  301  contact with the ear cartilage is made. Because the vibration of the cartilage conduction vibration source  225  is guided to a desired location by the vibration conductor  227 , and no requirement is made that the cartilage conduction vibration source  225  itself be arranged on the outer wall of the mobile telephone  301 , the configuration of such a cartilage conduction vibration unit is advantageous in that a greater amount of freedom is provided for the layout and in that the cartilage conduction vibration unit can be installed on a mobile telephone lacking any available extra space. 
     The fourth embodiment adds two further functionalities. However, these functionalities are not specific to the fourth embodiment, and can be applied to the first to third embodiments as well. One of the additional functionalities serves to prevent accidental operation of the cartilage conduction vibration unit. All of the first to fourth embodiments detect when the mobile telephone is brought up against an ear using the infrared light emitting units  19 ,  20  and the infrared light proximity sensor  21 ; however, in the first embodiment, for example, there is a concern that the proximity sensor will detect a case in which the inside of the mobile telephone  1  is lowered and placed on a desk or the like, and will accordingly falsely confirm that the mobile telephone  1  has been brought up against an ear, proceeding from step S 22  of the flow of  FIG. 4  to step S 24 . Because the same is not also true for the incline of the right ear call state detected in step S 24 , there is a possibility that the flow will proceed to step S 30  and the left-ear cartilage-conduction vibration unit  26  will erroneously be turned on. The vibration of the cartilage conduction vibration unit results in a comparatively large amount of energy, so vibration noise may be created with the desk when such mistaken operation occurs. To prevent this, the fourth embodiment is configured such that a horizontal stationary state is detected using the acceleration sensor  49 , and, when applicable, the cartilage conduction vibration source  225  is prohibited from vibrating. This point will be described in greater detail later. 
     Next, a description will be provided for the second additional functionality in the fourth embodiment. In each of the embodiments of the present invention, audio information is transmitted by having either the right-ear cartilage-conduction vibration unit  24  or the left-ear cartilage-conduction vibration unit  26  (in the fourth embodiment, the right end part  224  or left end part  226  of the vibration conductor  227 ) brought into contact with the tragus of the right ear or left ear; however, the contact pressure can be increased to obstruct the hole of the ear with the tragus, thereby creating an earplug bone conduction effect and conducting the audio information at an even higher volume. Further, because environment noise is blocked by the obstruction of the ear hole with the tragus, use in such a state achieves a listening status with dual effects, in which unnecessary environment noise is reduced and necessary audio information is increased; and is appropriate, for example, for calls to take place noisy environments or other situation. When the earplug bone conduction effect occurs, one&#39;s own voice becomes louder due to bone conduction from the vocal cords, and there is also a discomfort from the resulting imbalance in left and right auditory sensation. To ease the discomfort of one&#39;s own voice during the occurrence of such an earplug bone conduction effect, the fourth embodiment is configured such that the information of one&#39;s own voice picked up from the outgoing-talk unit  23  is subjected to phase inversion and transmitted to the cartilage conduction vibration source  225 , canceling out the sound of one&#39;s own voice. This point will be described in greater detail later. 
       FIG. 8  is a block diagram of the fourth embodiment, in which the same reference numerals are assigned to the same parts from  FIG. 7 . Also, because there are many portions in common with the first to third embodiments, corresponding portions are each assigned these same reference numerals. A description has been omitted for these identical or shared portions, unless there is a particular need. Although the telephone function unit  45  is illustrated in somewhat greater detail in the fourth embodiment, the configuration is shared among the first to third embodiments. More specifically, the incoming-talk-processing unit  212  and the earphone  213  of  FIG. 8  correspond to the incoming-talk unit  13  in  FIG. 3 , and the outgoing-talk-processing unit  222  and the microphone  223  in  FIG. 8  correspond to the outgoing-talk unit  23  in  FIG. 3 . On the other hand, the cartilage conduction vibration source  225  and the vibration conductor  227  in  FIG. 7  are depicted together in  FIG. 8  as the cartilage conduction vibration unit  228 . The outgoing-talk-processing unit  222  transmits a part of the audio from the operator picked up by the microphone  223  to the incoming-talk-processing unit  212  as a sidetone, and the incoming-talk-processing unit  212  superimposes the operator&#39;s own sidetone onto the voice of the calling party from the telephone communication unit  47  and outputs same to the earphone  213 , whereby the balance between the bone conduction and air conduction of one&#39;s own voice in the state in which the mobile telephone  301  is brought up against an ear is made to approximate a natural state. 
     The outgoing-talk-processing unit  222  further outputs a part of the audio from the operator picked up by the microphone  223  to an acoustics adjustment unit  238 . The acoustics adjustment unit  238  adjusts the acoustics of one&#39;s own voice, which are to be outputted from the cartilage conduction vibration unit  228  and transmitted to the cochlea, to acoustics approximating the operator&#39;s own voice transmitted to the cochlea by internal body conduction from the vocal cords during the occurrence of the earplug bone conduction effect; and effectively cancels out both. Also, a waveform inverter  240  subjects one&#39;s own voice, the acoustics of which have been adjusted in this manner, to waveform inversion, and outputs same to the phase adjustment mixer unit  236 . When the pressure detected by a pressure sensor  242  is at or above a predetermined range and the state corresponds to one in which the ear hole is obstructed at the tragus by the mobile telephone  301 , the phase adjustment mixer unit  236  mixes the output from the waveform inverter  240  according to an instruction from the controller  239  and drives the cartilage conduction vibration unit  228 . The excessive amount of one&#39;s own voice that occurs during the earplug bone conduction effect is thereby cancelled out, thus easing the discomfort. At this time, the degree of cancellation is regulated such that an amount of one&#39;s own voice equivalent to the sidetone remains without being cancelled out. On the other hand, a case in which the pressure detected by the pressure sensor  242  is lower than the predetermined level corresponds to a state in which the ear hole is not obstructed at the tragus and the earplug bone conduction effect does not occur; therefore, the phase adjustment mixer unit  236  will not mix the wavelength inversion output of one&#39;s own voice from the waveform inverter  240 , on the basis of the instruction of the controller  239 . However, the configuration may reverse the positions of the acoustics adjustment unit  238  and the waveform inverter  240  in  FIG. 8 . Moreover, the acoustics adjustment unit  238  and the waveform inverter  240  may be integrated as a function within the phase adjustment mixer unit  236 . 
       FIG. 9  is a conceptual block diagram illustrating the elements of the state in which the mobile telephone  301  is brought up against the tragus of the right ear in the fourth embodiment, and provides a description of how one&#39;s own voice is cancelled out during the occurrence of the earplug bone conduction effect.  FIG. 9  also depicts a particular embodiment of the pressure sensor  242 ; the configuration assumes that the cartilage conduction vibration unit  225  is a piezoelectric bimorph element. Equivalent parts have been given like reference numerals as in  FIGS. 7 and 8 , and a description has been omitted unless there is a particular need. 
       FIG. 9A  illustrates the state in which the mobile telephone  301  is brought up against the tragus  32  to such an extent that the tragus  32  does not obstruct the ear hole  232 . In such a state, the phase adjustment mixer unit  236  drives the cartilage conduction vibration unit  225  on the basis of the audio information of the calling party from the incoming-talk-processing unit  212 . The pressure sensor  242  is configured so as to monitor a signal appearing on a signal line linking the cartilage conduction vibration unit  225  to the phase adjustment mixer unit  236 , and detects signal variations that are based on strain to the cartilage conduction vibration unit (a piezoelectric bimorph element)  225  that is applied depending on the pressure on the vibration conductor  227 . Thus, when the cartilage conduction vibration unit  225  for transmitting audio information by being brought into contact with the tragus  32  comprises a piezoelectric bimorph element, the piezoelectric bimorph element can be made to also serve as a pressure sensor for detecting the pressure on the tragus  32 . The pressure sensor  242  further monitors a signal appearing on a signal line linking the incoming-talk-processing unit  212  to the phase adjustment mixer unit  236 . The signal appearing therein is not affected by the pressure on the tragus  32  and can therefore be utilized as a reference signal for determining the pressure. 
     In  FIG. 9A , as described above, the tragus  32  is in a state that does not obstruct the ear hole  232 , and the pressure sensor  242  determines that the pressure is small; therefore, on the basis of this determination, the controller  239  instructs the phase adjustment mixer unit  236  not to mix one&#39;s own waveform-inverted voice from the waveform inverter  240  into the cartilage conduction vibration unit  225 . On the other hand,  FIG. 9B  illustrates the state in which the mobile telephone  301  presses more strongly on the tragus  32  in the direction of arrow  302  and the tragus  32  obstructs the ear hole  232 . This state generates the earplug bone conduction effect. The pressure sensor  242  determines that the ear hole  232  has been obstructed on the basis of a detection of an increase to or above a predetermined pressure, and, on the basis of this determination, the controller  239  instructs the phase adjustment mixer unit  236  to mix one&#39;s own waveform-inverted voice from the waveform inverter  240  into the cartilage conduction vibration unit  225 . The discomfort of one&#39;s own voice during the occurrence of the earplug bone conduction effect is eased as described above. Conversely, when a reduction at or above a predetermined pressure from the state in  FIG. 9B  is detected by the pressure sensor  242 , the state is determined to be one in which, as in  FIG. 9A , the ear hole  232  is not obstructed, and the mixing of one&#39;s own waveform-inverted voice is discontinued. However, the pressure sensor  242  determines that there has been a transition between the states of  FIGS. 9A and 9B  on the basis of the absolute amount of pressure and the directionality of the pressure change. However, in a state of silence in which neither party speaks, the pressure sensor  242  detects the pressure by directly applying a pressure monitor signal, which is inaudible by ear, to the direct bone conduction vibration unit  225 . 
       FIG. 10  is a flow chart of the operation of the controller  239  in the fourth embodiment of  FIG. 8 . However, because the flow of  FIG. 10  has many points in common with the flow of the first embodiment in  FIG. 4 , corresponding parts have been given like step numerals, and a description has been omitted unless needed.  FIG. 10  also illustrates an abstraction of the operation that focuses on related functions, in order to primarily provide a description of the function of the cartilage conduction vibration unit  228 . Accordingly, similarly with respect to the case in  FIG. 4 , the controller  239  also contains typical mobile telephone functions and other operations not represented by the flow of  FIG. 10 .  FIG. 10  uses boldface print to illustrate points of difference with  FIG. 4 , and thus the following description focuses on these portions. 
     Step S 42  integrates step S 6  and step S 8  of  FIG. 4 , and is therefore illustrated such that the non-call processing of step S 42  includes the case of directly proceeding to the next step without any non-call operation, but the content thereof is identical to step S 6  and step S 8  in  FIG. 4 . Step S 44  integrates step S 10  and step S 12  of  FIG. 4 , and is therefore illustrated as a step for checking the presence or absence of a call state between two parties regardless of whether the call is incoming from the other party or is outgoing from oneself, but the content thereof is identical to step S 6  and step S 8  in  FIG. 4 . However, the fourth embodiment does not contain a step that would correspond to step S 16  in  FIG. 4 , because the configuration is not such that the mobile telephone  301  is opened or closed. 
     Step S 46  relates to the first addition function in the fourth embodiment and therefore checks for whether the mobile telephone  301  has left the hand-held state and remained stationary in a horizontal state for a predetermined period of time (for example, 0.5 seconds). When the proximity sensor has made a detection in step S 22 , step S 48  is first reached in a case in which it is confirmed in step S 46  that there is no such horizontal stationary state; the cartilage conduction vibration source  225  is then turned on. On the other hand, in a case in which a horizontal stationary state is detected in step S 46 , the flow proceeds on to step S 50 , which turns off the cartilage conduction vibration source  225 , and the flow returns to step S 14 . However, step S 50  corresponds to when, in a flow repetition to be described later, the cartilage conduction vibration source  225  reaches step S 46  in an on state and a horizontal stationary state has been detected; therefore, when the cartilage conduction vibration source  225  reaches step S 50  in an off state, the flow returns to step S 14  without any action being performed. 
     Step S 52  relates to the second added function in the fourth embodiment, and checks for the occurrence of the earplug bone conduction effect, which is caused by the mobile telephone  301  pressing strongly on the tragus  32  and obstructing the ear hole  232 . In particular, as illustrated in  FIG. 9 , this is checked by the presence or absence of a change at or above a predetermined pressure and the directionality thereof by the pressure sensor  242 . In a case in which there is a detection of the state in which the earplug bone conduction effect is created, the flow proceeds to step S 54 , which adds the waveform-inversion signal of one&#39;s own voice to the cartilage conduction vibration source  225 , and the flow then moves on to step S 58 . On the other hand, in a case in which there is a detection in step S 52  of a state in which the earplug bone conduction effect is not created, the flow moves on to step S 56 , and then on to step S 58  without adding the waveform-inversion signal of one&#39;s own voice to the cartilage conduction vibration source  225 . In step S 58 , there is performed a check for whether or not a call state has been cut off; when the call is not cut off, the flow returns to step S 22 , following which step S 22  and step S 46  to S 58  are repeated until a call interruption is detected in step S 58 . Support is thereby provided for the generation and elimination of the earplug bone conduction effect during a call. 
     The various features of each of the embodiments described above are not to be restricted to individual respective embodiments, but rather can be substituted or combined with other appropriate embodiments. For example, the flow chart of the fourth embodiment in  FIG. 10  does not have the configuration in the flow chart of the first embodiment in  FIG. 4  for switching the right-ear cartilage-conduction vibration unit  24  and the left-ear cartilage-conduction vibration unit  26 , but the configuration may be such that the right-ear cartilage-conduction vibration unit  24  and the left-ear cartilage-conduction vibration unit such as in the first embodiment are utilized as the configuration of the cartilage conduction vibration unit  228  in the tenth embodiment; thus, in addition to support for the generation and elimination of the earplug bone conduction effect in repeating the loop of step S 22  and steps S 46  to S 58 , support is additionally provided for switching the mobile telephone to the other hand between the right ear call state and the left ear call state by the function according to steps S 24  to S 26  from  FIG. 4 . It is also possible to add to the first to third embodiments the functionality of checking for the horizontal stationary state and turning off the cartilage conduction vibration unit  228  in the fourth embodiment of  FIG. 10 . It is moreover possible in the first through third embodiments to utilize the cartilage conduction vibration unit  228  as in the fourth embodiment. 
     Fifth Embodiment 
       FIG. 11  is a perspective view illustrating a fifth embodiment of the mobile telephone according to an aspect of the present invention. The fifth embodiment is founded on the fourth embodiment of  FIG. 7 , and shares the majority of the structure thereof; thus, corresponding parts have been given like reference numerals, and a description thereof has been omitted. Also, to avoid complicating the illustration, the assignment of the reference numerals themselves has also been omitted for those portions for which the description has been omitted, but the functions and names of the common parts in the drawings are common with  FIG. 7 . However, a more detailed description of the configuration calls on the essential points of the block diagram of the fourth embodiment in  FIGS. 8 and 9 . A first point of difference in the fifth embodiment from the fourth embodiment lies in that a mobile telephone  401  is provided with a double-push button  461 , which makes it possible to set a so-called touch panel function (a function in which the large-screen display unit  205 , on which the key pad or other operation unit  209  is displayed, is touched with a finger and the GUI is operated by the detection of this touch position and/or the detection of this swipe) to off, and also which is only usable when this touch panel function has been set to off. The touch panel function can be set to off by operating the touch panel itself, and the touch panel can also be set to return to on by pressing the double-push button  461  for a predetermined period of time or longer. The double-push button  461 , when usable, also has a function for initiating a call with a first push and for interrupting a call when there is a second push during the call (an alternate switching function performed by pushing whether the device is on or off). The above-described first push of the double-push button  461  is performed either to call a specific party or to respond to an incoming call, a call being initiated thereby in either case. 
     A second point of difference in the fifth embodiment from the fourth embodiment lies in that the fifth embodiment is configured so as to function by the combination of the mobile telephone  401  with a softcover  463  for housing same. Although  FIG. 11 , for the sake of describing the configuration, depicts the softcover  463  as if it were transparent, the softcover  463  is actually opaque, and the mobile telephone  401  cannot be seen from the outside in the state in which the mobile telephone  401  is housed in the softcover  463  as in  FIG. 11 . 
     The above-described double-push button  461  is also able to function when the double-push button  461  is pushed from on the softcover  463  in the state in which the mobile telephone  401  has been housed in the softcover  463 . Furthermore, the softcover  463  is configured so as to interlock with the cartilage conduction vibration unit  228  comprising the cartilage conduction vibration source  225  and vibration conductor  227  of the mobile telephone  401 , allowing for a call to take place in the state in which the mobile telephone  401  is housed in the softcover  463 . The following provides a description thereof. 
     The softcover  463  is made using an elastic material that has acoustic impedance approximating that of ear cartilage (a silicone rubber; a mixture of a silicone rubber and a butadiene rubber; a natural rubber; a structure formed using these varieties of rubber in which air bubbles are sealed; a structure, such as can be seen in transparent packaging sheet materials or the like, in which a layer of groups of air bubbles is sealed separated by a thin film of synthetic resin; or the like). The vibration conductor  227  for transmitting vibration from the cartilage conduction vibration source  225  is in contact with the inside of the softcover when the mobile telephone  401  is housed therein. The outside of the softcover  463  is brought up against the ear with the mobile telephone  401  housed therein, whereby the vibration of the vibration conductor  227  is transmitted to the ear cartilage over a broad area of contact by the interposition of the softcover  463 . Sound from the exterior of the softcover  463 , which resonates in accordance with the vibration of the vibration conductor  227 , is further transmitted to the tympanic membrane from the external auditory meatus. Sound source information from the cartilage conduction vibration source  225  can thereby be heard as a loud sound. Environment noise can also be blocked, because the softcover  463 , which is brought up against the ear, has a form such that the external auditory meatus is obstructed. Increasing the force with which the softcover  463  is pressed against the ear furthermore gives the result of substantially completely obstructing the external auditory meatus, and sound source information from the cartilage conduction vibration source  225  can be heard as an even louder sound due to the earplug bone conduction effect. Detection is done via the softcover  463 , but, similarly with respect to the fourth embodiment, in the state in which the earplug bone conduction effect is created, the waveform inversion signal from the outgoing-talk unit  23  (the microphone  223 ) is added to the signal of one&#39;s own voice, on the basis of the detection of pressure by the cartilage conduction vibration source  225 . 
     In a call state in which the mobile telephone  401  remains housed in the softcover  463 , the vibration of the vibration conductor  227 , which is transmitted to the softcover  463 , is also transmitted to the outgoing-talk unit  23 , which has the potential to generate a Larsen effect. To block acoustic conduction between the vibration conductor  227  and the outgoing-talk unit  23  as a countermeasure therefor, the softcover  463  is provided in between the two with an insulation ring unit  465  having an acoustic impedance different from that of the body of the softcover. The insulation ring unit  465  can be formed by either integrating or joining a material different from the material of the body of the softcover. The insulation ring unit  465  may also be formed by joining a layer having a different acoustic impedance to either the outside or the inside of the softcover  463 , which are molded with the same material. Moreover, a plurality of insulation ring units  465  may be interposed between the vibration conductor  227  and the outgoing-talk unit  23  so that the insulating effect may be increased. 
     In order for the softcover  463  to permit a call to take place in the state in which the mobile telephone  401  remains housed therein, the vicinity of the outgoing-talk unit  23  (the microphone  223 ) is configured as a microphone cover unit  467 , which does not interfere with the air conduction of sound. Such a microphone cover unit  467  takes a sponge-like structure such as that of, for example, an earphone cover or the like. 
       FIG. 12  is a flow chart of the operation of the controller  239  (borrowing from  FIG. 8 ) in the fifth embodiment of  FIG. 11 . However, parts that the flow of  FIG. 12  shares with the flow of  FIG. 10  have been given like step reference numerals, and a description thereof has been omitted.  FIG. 12  also primarily serves to describe the functions of the cartilage conduction vibration unit  228  and therefore depicts an abstraction of the operation that focuses on the related functions. Accordingly, similarly with respect to  FIG. 10  or the like, the controller  239  in the fifth embodiment also contains typical mobile telephone functions and other operations that are not represented in the flow in  FIG. 12 . 
     When the flow of  FIG. 12  reaches step S 62 , a check is performed for whether or not the touch panel has been set to off by the operation described above. When same has not been set to off, the flow moves on to step S 64 , and the function of the double-push button  461  is deactivated, whereupon the flow moves on to step S 66  before arriving at step S 34 . The portion illustrated as typical processing in step S 66  collectively integrates step S 14 , steps S 18  to S 22 , step S 32 , step S 36 , step S 38 , and steps S 42  to S 58  in  FIG. 10  (i.e., the portions between steps S 4  and S 34 ). In other words, in a case in which step S 62  transitions to step S 64 , the flow in  FIG. 12  implements similar functions to those of  FIG. 10 . 
     On the other hand, when it is detected in step S 62  that the touch panel has been set to off, the flow moves on to step S 68 , in which the function of the double-push button  461  is activated. The flow then proceeds to step S 70 . In step S 70 , the function of the touch panel is deactivated, and in step S 72 , the presence or absence of a first push on the double-push button  461  is detected. In a case in which herein no push is detected, the flow moves on directly to step S 34 . On the other hand, in a case in which a first push on the double-push button  461  is detected in step S 72 , the flow proceeds to step S 74 , which detects whether or not the mobile telephone  401  has been housed in the softcover  463 . This detection is made possible, for example, by the function of the infrared light-emitting units  19 ,  20  and the infrared light proximity sensor  21 , which constitute the proximity sensor. 
     When housing in the softcover  463  is detected in step S 74 , the flow proceeds to step S 76 , which turns the outgoing-talk unit  23  on, and turns the incoming-talk unit  13  off. Further, step S 78  turns the cartilage conduction vibration source  225  on and the flow proceeds to step S 80 , which places the mobile telephone  401  in a call state. When a call state is already in effect, the same is continued. On the other hand, in a case in which housing in the softcover  463  is not detected in step S 74 , the flow moves on to step S 82 , which turns both the outgoing-talk unit  23  and the incoming-talk unit  13  on; further, step S 84  turns the cartilage conduction vibration source  225  off and the flow proceeds to step S 80 . Step S 86 , which follows step S 80 , runs processing for the earplug bone conduction effect, and then the flow moves on to step S 88 . The processing for the earplug bone conduction effect in step S 86  is collectively illustrated by steps S 52  to S 56  in  FIG. 10 . 
     In step S 88 , the presence or absence of a second push on the double-push button  461  is detected. When there is no detection, the flow returns to step S 74 , following which steps S 74  to S 88  are repeated until there is a detection of a second push on the double-push button  461 . There is a constant check for whether the mobile telephone  401  is housed in the softcover  463  during this repetition during a call; therefore, when, for example, environment noise is loud and listening comprehension at the incoming-talk unit  13  is impaired, support is provided for the user to house the mobile telephone  401  in the softcover  463  and thereby block environment noise and further ease listening comprehension by the earplug bone conduction effect. 
     On the other hand, when a second push on the double-push button  461  is detected in step S 88 , the flow moves on to step S 90 , which interrupts the call; step S 92  also turns all sending and receiving functions off and the flow arrives at step S 34 . In step S 34 , there is performed a check for whether the primary power source is off; therefore, when there is no detection of the primary power source being off, the flow returns to step S 62 , following which steps S 62  to S 92  and step S 34  are repeated. Further, during this repetition, step S 64  provides support for setting the touch panel to off by the previously described operation of the touch panel or for releasing the off setting by a long press on the double-push button  461 , and therefore switch is possible with appropriate, ordinary processing. 
     Sixth Embodiment 
       FIG. 13  is a perspective view illustrating a sixth embodiment of the mobile telephone according to an aspect of the present invention.  FIG. 13A  is a front perspective view similar to  FIG. 7 , but, as will be described later, because the sixth embodiment is constituted as a digital camera provided with mobile telephone functions,  FIG. 13A  is rotated 90 degrees relative to  FIG. 7  and depicted at the angle of the state of use as a digital camera.  FIG. 13B  is a rear perspective view thereof (a front perspective view in a case viewed as a digital camera), and  FIG. 13C  is a cross-sectional view in the B-B sectional plane in  FIG. 13B . 
     The sixth embodiment is founded on the fourth embodiment of  FIG. 7 , and has the majority of the structure thereof in common; thus, corresponding parts have been given like reference numerals, and a description thereof has been omitted. Also, to avoid complicating the illustration, the assignment of the reference numerals themselves has also been omitted for those portions for which the description has been omitted, but the functions and names of the common parts in the drawings are in common with those of  FIG. 7 . However, a more detailed description of the configuration calls on the essential points of the block diagram of the fourth embodiment in  FIGS. 8 and 9 . A first point of difference in the sixth embodiment from the fourth embodiment lies in that a mobile telephone  501  is constituted as a digital camera provided with mobile telephone functions. That is, as illustrated in  FIG. 13B , the first point of difference is that a zoom lens  555  provided with high optical performance is utilized as the imaging lens of the backside main camera. The zoom lens  555  projects out during use in the state illustrated by the single dotted line in  FIG. 13B , but, during non-use, takes a so-called collapsible lens configuration, which retracts to a position forming a plane identical to that of the outer surface of the mobile telephone  501 . A strobe  565  and a shutter release button  567  for projecting auxiliary light when the subject is dark are also provided. The mobile telephone  501  also has a grip unit  563  suited for when the camera is held in the right hand. 
     A second point of difference in the sixth embodiment from the fourth embodiment lies in that the grip unit  563 , similarly with respect to the softcover  463  in the fifth embodiment, is made using a material that has acoustic impedance approximating that of ear cartilage (a silicone rubber; a mixture of a silicone rubber and a butadiene rubber; a natural rubber; or a structure formed from these varieties of rubber in which air bubbles are sealed), and is provided with an elasticity suited for providing a satisfactory grip sensation. Also, unlike the arrangement in the fourth embodiment, a cartilage conduction vibration source  525  is arranged on the reverse side of the grip unit  563 . As is clear from the cross-section in  FIG. 13C , the cartilage conduction vibration source  525  is in contact with the rear side of the grip unit  563 . 
     Accordingly, bringing the grip unit  563  up against the ear transmits the vibration of the cartilage conduction vibration source  525  to the ear cartilage over a broad area of contact by the interposition of the grip unit  563 . Moreover, sound from the exterior of the grip unit  563 , which resonates according to the vibration of the cartilage conduction vibration source  525 , is transmitted to the tympanic membrane from the external auditory meatus. Sound source information from the cartilage conduction vibration source  525  can thereby be heard as a loud sound. Also, similarly with respect to the fifth embodiment, the grip unit  563 , which is brought up against the ear, takes on a form such that the external auditory meatus is obstructed, and can therefore block environment noise. Further similarly with respect to the fifth embodiment, increasing the force for pressing the grip unit  563  gives the result of substantially completely obstructing the external auditory meatus, and sound source information from the cartilage conduction vibration source  525  can be heard as an even louder sound due to the earplug bone conduction effect. Detection is made via the grip unit  563 , but, similarly with respect to the fifth embodiment, in the state in which the earplug bone conduction effect is created, the waveform inversion signal from a microphone or other outgoing-talk unit  523  is added to the signal of one&#39;s own voice, on the basis of the detection of pressure by the cartilage conduction vibration source  525 . 
     Unlike the fourth embodiment, the outgoing-talk unit  523  is provided not to the front surface of the mobile telephone  501  but rather to the end surface thereof, as is clear from  FIG. 13B . Accordingly, the outgoing-talk unit  523  can consistently pick up the user&#39;s voice both when the incoming-talk unit  13  is brought up against the ear for a call and when the grip unit  563  on the reverse side is brought up against the ear for a call. The settings can be switched using a switch button  561  for either activating the incoming-talk unit  13  or for activating the cartilage conduction vibration source  525 . In the state in which the zoom lens  555  projects in the state illustrated by the single dotted line in  FIG. 13B , it is inappropriate to bring the grip unit  563  up against the ear for a call; therefore, when the switch button is operated in such a state and the setting is changed to activate the cartilage conduction vibration source  525 , the zoom lens  555  collapses automatically, the execution of this switch being reserved until the collapse is complete. 
       FIG. 14  is a flow chart of the operation of the controller  239  (borrowing from  FIG. 8 ) in the sixth embodiment of  FIG. 13 . However, parts that the flow of  FIG. 14  shares with the flow of  FIG. 10  have been given like step reference numerals, and a description thereof has been omitted.  FIG. 14  also illustrates an abstraction of the operation that focuses on related functions, in order to primarily provide a description of the function of the cartilage conduction vibration unit  228 . Accordingly, similarly with respect to  FIG. 10  and the like, in the sixth embodiment as well, the controller  239  also contains typical mobile telephone functions and other operations not represented by the flow in  FIG. 14 . 
     In the flow of  FIG. 14 , there is performed a check for whether there has been an operation to initiate a call once step S 104  is reached. In a case in which there has not been an operation, the flow moves directly on to step S 34 . On the other hand, in a case in which an operation to initiate a call is detected, the flow proceeds to step S 106 , in which there is performed a check for whether the cartilage conduction has been set using the switch button  561 . When the cartilage conduction has been set, there is a check in step S 108  for whether the zoom lens  555  is projecting out. A result in which the zoom lens  555  is not projecting out moves on to step S 110 , in which the outgoing-talk unit  523  is turned on and the incoming-talk unit  13  is turned off; step S 112  turns the cartilage conduction vibration source  525  on and then the flow moves on to step S 46 . 
     On the other hand, in a case in which no cartilage conduction setting is detected in step S 106  the flow moves on to step S 114 , in which the outgoing-talk unit  523  and the incoming-talk unit  13  are turned on; step S 116  turns the cartilage conduction vibration source  525  off and the flow moves on to step S 118 . Furthermore, in a case in which it is detected in step S 108  that the zoom lens  555  is projecting out when it is also detected in step S 106  that the cartilage conduction has been set, the flow moves on to step S 111 , which instructs that the zoom lens  555  be collapsed, and the flow moves on to step S 114 . However, in a case in which collapsing has already been initiated, the instruction is that same be continued. As will be described later, steps S 106  to S 116  are repeated until the call state is cut off. Thus, there is an instruction to collapse in step S 111  in accordance with a cartilage conduction setting detection in step S 106 , and after the collapsing has been initiated, the state of steps S 114  and S 116  is maintained without the flow moving on to step S 110  until the collapsing is completed and the projection of the zoom lens  555  is no longer detected in step S 108 . 
     Steps S 46  to S 56 , which follow step S 112 , are consistent with  FIG. 10  and therefore a description thereof has been omitted. Upon the move to step S 54  or steps S 56  to S 118 , a check is done for whether the call state has been cut off, and in a case in which a call interruption is not detected, the flow returns to step S 106 , following which steps S 106  to S 118  and steps S 46  to S 56  are repeated. When, for example, environment noise is loud and when listening comprehension is impaired at the incoming-talk unit  13 , support can thereby be provided for the user to operate the switch button  561  during a call to switch to the cartilage conduction setting and thereby block environment noise or further ease listening comprehension by the earplug bone conduction effect, and the like. Also, at this time the zoom lens  555  is automatically collapsed when in the projecting state. 
     Seventh Embodiment 
       FIG. 15  is a perspective view illustrating a seventh embodiment of a mobile telephone according to an aspect of the present invention. A mobile telephone  601  of the seventh embodiment, similarly with respect to the first embodiment, is configured such that an upper part  607  can be folded onto a lower part  611  by a hinge unit  603 .  FIG. 15A  is a front perspective view similar to  FIG. 1 , and  FIG. 15B  is a rear perspective view thereof.  FIG. 15C  is a cross-sectional view of the elements in the B-B sectional plane in  FIG. 15B . The majority of the structure of the seventh embodiment is shared with that of the first embodiment, and therefore corresponding parts have been assigned the same reference numerals, and a description has been omitted. Also, to avoid complicating the illustration, the assignment of the reference numerals themselves has also been omitted for those portions for which the description has been omitted, but the functions and names of the common parts in the drawings are common with  FIG. 1 . Furthermore, although the overview is shared with the first embodiment, a more detailed description of the internal configuration calls on the essential points of the block diagram of the fourth embodiment in  FIGS. 8 and 9 . 
     A first point of difference in the seventh embodiment from the first embodiment lies in that, as depicted in  FIG. 15B , a cartilage conduction output unit  663  having a broad surface area is provided in the vicinity of the hinge of the upper part  607 . The cartilage conduction output unit  663  is similar to the softcover  463  in the fifth embodiment and/or to the grip unit  563  in the sixth embodiment, and is made using a material that has acoustic impedance approximating that of ear cartilage (a silicone rubber; a mixture of a silicone rubber and a butadiene rubber; a natural rubber; or a structure formed using these varieties of rubber in which air bubbles are sealed), and is provided with an elasticity suited for protecting against collision of a foreign object against the outer wall of the mobile telephone  601 . Unlike the arrangement in the first embodiment, a cartilage conduction vibration source  625  is arranged behind the cartilage conduction output unit  663 . As is clear from the cross-section of  FIG. 15C , the cartilage conduction vibration source  625  is in contact with the rear surface of the cartilage conduction output unit  663 . 
     Accordingly, folding the mobile telephone  601  and bringing the cartilage conduction output unit  663  up against the ear transmits the vibration of the cartilage conduction vibration source  625  to the ear cartilage over a broad area of contact by the interposition of the cartilage conduction output unit  663 . Sound from the exterior of the cartilage conduction output unit  663 , which resonates in accordance with the vibration of the cartilage conduction vibration source  625 , is further transmitted to the tympanic membrane from the external auditory meatus. Sound source information from the cartilage conduction vibration source  625  can thereby be heard as a loud sound. Also, similarly with respect to the fifth embodiment and the sixth embodiment, the cartilage conduction output unit  663 , which is brought up against the ear, takes on a form such that the external auditory meatus is obstructed, and can therefore block environment noise. Further similarly with respect to the fifth embodiment and the sixth embodiment, increasing the force with which the cartilage conduction output unit  663  is pressed to the ear gives the result of substantially completely obstructing the external auditory meatus, and sound source information from the cartilage conduction vibration source  625  can be heard as an even louder sound due to the earplug bone conduction effect. Detection is done via the cartilage conduction output unit  663 , but, similarly with respect to the fifth embodiment and the sixth embodiment, in the state in which the earplug bone conduction effect is created, the waveform inversion signal from a microphone or other outgoing-talk unit  623  is added to the signal of one&#39;s own voice, on the basis of the detection of pressure by the cartilage conduction vibration source  625 . 
     A second point of difference in the seventh embodiment from the first embodiment lies in that, as depicted in  FIG. 15A , the outgoing-talk unit  623  is provided to the lower end surface of the lower part  611 , rather than to the front surface of the lower part  611  of the mobile telephone  601 . Accordingly, the outgoing-talk unit  623  can consistently pick up the user&#39;s voice both when the mobile telephone  601  is opened and the incoming-talk unit  13  is brought up against the ear for a call and when the mobile telephone  601  is closed and the cartilage conduction output unit  663  is brought up against the ear for a call. In a case in which the mobile telephone  601  is set to support switching cartilage conduction, switching occurs automatically such that the incoming-talk unit  13  is activated when the mobile telephone  601  is opened and a cartilage conduction vibration source  625  is activated when the mobile telephone  601  is closed. On the other hand, in a case in which there is no setting to support switching the cartilage conduction, the cartilage conduction vibration source  525  will not automatically be activated; rather, ordinary speaking and listening function regardless of whether the mobile telephone  601  is open or closed. 
     As is clear from the rear perspective view in  FIG. 15B , the back surface of the mobile telephone  601  is provided with a backside main camera  55 , a speaker  51 , and a back surface display unit  671 . The back surface of the mobile telephone  601  is further provided with a pushbutton  661 , which becomes active when the cartilage conduction switching support is set and the mobile telephone  601  is closed. Similarly with respect to the fifth embodiment, the pushbutton  661  has the functions of initiating a call with a first push, and of interrupting a call when pushed a second time during a call. The first push of the pushbutton  661  is performed either to place an outgoing call to a specific party or to respond to an incoming call, a call being initiated thereby in either case. 
       FIG. 16  is a flow chart of the operation of the controller  239  (borrowing from  FIG. 8 ) in the seventh embodiment of  FIG. 15 . However, parts that the flow of  FIG. 16  shares with the flow of  FIG. 14  have been given like step reference numerals, and a description thereof has been omitted.  FIG. 16  also illustrates an abstraction of the operation that focuses on related functions, in order to primarily provide a description of the function of the cartilage conduction vibration unit  228 . Accordingly, in the seventh embodiment, the controller  239  also contains typical mobile telephone functions and other operations not represented by the flow of  FIG. 16 , similarly with respect to  FIG. 14  and the like. 
     In the flow of  FIG. 16 , a call is initiated and when step S 122  is reached, there is performed a check for whether cartilage conduction switching support has been set. In a case in which cartilage conduction switching support is confirmed to have been set in step S 122 , the flow proceeds to step S 124 , which checks for whether or not the mobile telephone  601  has been opened; i.e., has gone from the state in which the upper part  607  is folded on top of the lower part  611  to the state of being opened as in  FIG. 15 . In a case in which it is confirmed that the mobile telephone  601  has not been opened and the upper part  607  is folded on top of the lower part  611 , the flow moves on to step S 110 , which turns the outgoing-talk unit  623  on and turns the incoming-talk unit  13  off; step S 112  turns the cartilage conduction vibration source  625  on and then the flow moves on to step S 46 . Thus, it becomes possible to listen using the cartilage conduction output unit  663  in the state in which the mobile telephone  601  is folded up. 
     On the other hand, in a case in which it is not detected in step S 122  that the cartilage conduction switching support has been set, no question is posed as to whether or not the mobile telephone  601  is folded up, but rather the flow moves on to step S 114 , which turns the outgoing-talk unit  623  and the incoming-talk unit  13  on together; step S 116  then turns the cartilage conduction vibration source  625  off and moves on to step S 118 . In a case in which it is detected in step S 106  that the cartilage conduction switching support has been set, the flow moves on to step S 114  even when it is confirmed in step S 124  that the mobile telephone  601  is open. 
     The flow in  FIG. 16  also has a check for whether or not the call state has been cut off in step S 118 ; the flow returns to step S 122  in a case in which a call interruption is not detected, following which step S 122 , step S 124 , steps S 114  to S 118  and steps S 46  to S 56  are repeated. Thus, in a case in which the cartilage conduction switching support has been pre-set, when, for example, environment noise is loud and when listening comprehension is impaired at the incoming-talk unit  13 , support can be provided for the user to fold up the mobile telephone  601  during the course of a call and switch to listening by the cartilage conduction output unit  663 , and thereby block environment noise or further ease listening comprehension by the earplug bone conduction effect, and the like. 
     To summarize the features of the aforementioned fifth to sixth embodiments, the mobile telephone comprises a cartilage conduction vibration source and a conductor for guiding the vibration of the cartilage conduction vibration source to the ear cartilage; the conductor either is configured as an elastic body, or is large enough to be in contact with the ear cartilage at a plurality of points or is large enough to be in contact with the ear cartilage and obstruct the external auditory meatus, or has a surface area at least approximating that of an earlobe, or has an auditory impedance approximating the auditory impedance of ear cartilage. Any of these features or a combination thereof makes it possible to listen effectively to sound information by the cartilage conduction vibration source. The use of these features is also not to be limited to the above-described embodiments. For example, it is also possible to constitute the present invention without having the conductor be an elastic body, by the use of the advantages of the materials, sizes, surface areas, arrangements, and structures disclosed in the above-described embodiments. 
     Eighth Embodiment 
       FIG. 17  is a perspective view illustrating an eighth embodiment of the mobile telephone according to an aspect of the present invention. The eighth embodiment is similar to the sixth embodiment of  FIG. 13 , and is configured as a digital camera provided with a mobile telephone function; similarly with respect to  FIG. 13 ,  FIG. 17A  is a front perspective view,  FIG. 17B  is a rear perspective view, and  FIG. 17C  is a cross-sectional view in the B-B sectional plane in  FIG. 17B . The eighth embodiment shares the majority of the structure with the sixth embodiment of  FIG. 13 ; thus, corresponding parts have been given like reference numerals, and a description thereof has been omitted. 
     The point of difference in the eighth embodiment from the sixth embodiment lies in that, as is clear from the cross-section of  FIG. 17C , a cartilage conduction vibration source  725  is embedded inside a grip unit  763 . The grip unit  763 , similarly with respect to the sixth embodiment in  FIG. 13 , is made using a material that has acoustic impedance approximating that of ear cartilage (a silicone rubber; a mixture of a silicone rubber and a butadiene rubber; a natural rubber; or a structure formed using these varieties of rubber in which air bubbles are sealed), and is provided with an elasticity suited for providing a satisfactory grip sensation. A more detailed description of the internal configuration, similarly with respect to the sixth embodiment, calls on the essential points of the block diagram of the fourth embodiment in  FIGS. 8 and 9 . 
     A flexible connection wire  769  in  FIG. 17C  connects the cartilage conduction vibration source  725 , which is embedded inside the grip unit  763 , with the phase adjustment mixer unit  236  of  FIG. 8  or other circuit portion  771 . The structure as illustrated by the cross-sectional view in  FIG. 17C , for embedding the cartilage conduction vibration source  725  inside the grip unit  763 , can be achieved by an integrated mold in which the cartilage conduction vibration source  725  and the flexible connection wire  769  are inserted into the grip unit  763 . The same can also be achieved by dividing the grip unit  763  into two bodies, where the flexible connection wire  769  and the cartilage conduction vibration source  725  serve as a boundary, and by bonding the two grip units  763  across the flexible connection wire  769  and the cartilage conduction vibration source  725 . 
     The eighth embodiment is similar to the sixth embodiment in that bringing the grip unit  763  up against the ear transmits the vibration of the cartilage conduction vibration source  725  to the ear cartilage over a broad area of contact by the interposition of the grip unit  763 ; in that sound from the exterior of the grip unit  763 , which resonates in accordance with the vibration of the cartilage conduction vibration source  725 , is further transmitted to the tympanic membrane from the external auditory meatus; in that environment noise can also be blocked, because the grip unit  763 , which is brought up against the ear, has a form such that the external auditory meatus is obstructed; and in that increasing the force pressing the grip unit  763  to the ear furthermore gives the result of substantially completely obstructing the external auditory meatus, and sound source information from the cartilage conduction vibration source  725  can be heard as an even louder sound due to the earplug bone conduction effect. In the state in which the earplug bone conduction effect is created, the adding of the waveform inversion signal from the microphone or other outgoing-talk unit  523  to the signal of one&#39;s own voice, on the basis of the detection of pressure by the cartilage conduction vibration source  625 , is the same as in the sixth embodiment. However, because the cartilage conduction vibration source  725  is embedded in the grip unit  763  in the eighth embodiment, the state in which the earplug bone conduction effect is created is detected by the strain to the cartilage conduction vibration source  725 , which is caused by the strain to the grip unit  763  due to an increase in the pushing force. 
     The significance of embedding the cartilage conduction vibration source  725  inside an elastic body such as the grip unit  763  in the eighth embodiment lies not only in obtaining a favorable conduction of sound, as described above, but also in counteracting impact on the cartilage conduction vibration source  725 . A piezoelectric bimorph element, which is used as the cartilage conduction vibration source  725  in the eighth embodiment, has properties for resisting impact. Herein, configuring the cartilage conduction vibration source  725  so as to be enveloped circumferentially, as in the eighth embodiment, can provide cushioning against impact resulting from the rigid structure of the mobile telephone  701 , and can facilitate implementation in the mobile telephone  701 , which is constantly exposed to such risks as being dropped. The elastic body enveloping the cartilage conduction vibration source  725  not only functions simply as a cushioning material, but also functions as a configuration for more effectively transmitting the vibration of the cartilage conduction vibration source  725  to the ear as described above. 
     Ninth Embodiment 
       FIG. 18  is a perspective view illustrating a ninth embodiment of a mobile telephone according to an aspect of the present invention. A mobile telephone  801  of the ninth embodiment, similarly with respect to the seventh embodiment, is configured such that an upper part  807  can be folded onto the lower part  611  by a hinge unit  603 . In  FIG. 18 , which is similar to  FIG. 15 ,  FIG. 18A  is a front perspective view,  FIG. 18B  is a rear perspective view, and  FIG. 18C  is a cross-sectional view in the B-B sectional plane in  FIG. 18B . The eighth embodiment in  FIG. 18  shares the majority of the structure with the seventh embodiment of  FIG. 15 ; thus, corresponding parts have been given like reference numerals, and a description thereof has been omitted. 
     A point of difference in the ninth embodiment from the seventh embodiment lies in that, as is clear from the cross-section of  FIG. 18C , a cartilage conduction vibration source  825  is sandwiched between a cartilage conduction output unit  863  and an internal cushioning material  873 . The cartilage conduction output unit  863 , similarly with respect to the cartilage conduction output unit  663  in the seventh embodiment, is made using a material that has acoustic impedance approximating that of ear cartilage (a silicone rubber; a mixture of a silicone rubber and a butadiene rubber; a natural rubber; or a structure formed using these varieties of rubber in which air bubbles are sealed), and is provided with an elasticity suited for protecting against the collision of a foreign object against the outer wall of the mobile telephone  801 . The internal cushioning material  873  can be constituted of any material provided that the material is an elastic body having the purpose of providing cushioning, but can also be made of the same material as the cartilage conduction output unit  863 . A more detailed description of the internal configuration, which is similar to the seventh embodiment, calls on the essential points of the block diagram of the fourth embodiment in  FIGS. 8 and 9 . 
     As illustrated by the cross-section in  FIG. 18C , the cartilage conduction vibration source  825  and a flexible connection wiring  869  are sandwiched in between the cartilage conduction output unit  863  and the internal cushioning material  873 . The flexible connection wire  869 , similarly with respect to the eighth embodiment, connects the cartilage conduction vibration source  825  with the phase adjustment mixer unit  236  of  FIG. 8  or other circuit portion  871 . These structures, in which the cartilage conduction vibration source  825  and the flexible connection wire  869  are sandwiched in between the cartilage conduction output unit  863  and the internal cushioning material  873 , are integrated within a cartilage conduction output unit  875 ; such a cartilage conduction output unit  875  is fitted into the upper part  807  of the mobile telephone  801 . 
     The ninth embodiment is also similar to the seventh embodiment in that bringing the cartilage conduction output unit  863  up against the ear transmits the vibration of the cartilage conduction vibration source  825  to the ear cartilage over a broad area of contact by the interposition of the cartilage conduction output unit  863 ; in that sound from the cartilage conduction output unit  863 , which resonates in accordance with the vibration of the cartilage conduction vibration source  825 , is transmitted to the tympanic membrane from the external auditory meatus; in that environment noise can be blocked, because the cartilage conduction output unit  863 , which is brought up against the ear, has a form such that the external auditory meatus is obstructed; and in that increasing the force pressing the cartilage conduction output unit  863  to the ear gives the result of substantially completely obstructing the external auditory meatus, and sound source information from the cartilage conduction vibration source  825  can be heard as an even louder sound due to the earplug bone conduction effect. In the state in which the earplug bone conduction effect is created, the adding of the waveform inversion signal from the microphone or other outgoing-talk unit  623  to the signal of one&#39;s own voice, on the basis of the detection of pressure by the cartilage conduction vibration source  825 , is the same as in the seventh embodiment. However, in the ninth embodiment, the cartilage conduction vibration source  825  is sandwiched in between the cartilage conduction output unit  863  and the internal cushioning material  873 , which both are elastic bodies, and therefore, similarly with respect to the eighth embodiment, the state in which the earplug bone conduction effect is created is detected by the strain to the cartilage conduction vibration source  825 , which accompanies the strain to the cartilage conduction output unit  863  due to an increase in the pushing force. 
     The significance of the structure in the ninth embodiment, in which the cartilage conduction vibration source  825  is sandwiched between the cartilage conduction output unit  863  and the internal cushioning material  873 , which are both elastic bodies, lies not only in obtaining a favorable conduction of sound, as described above, but also in counteracting impact on the cartilage conduction vibration source  825 , which is made of a piezoelectric bimorph element. In other words, similarly with respect to the eighth embodiment, configuring the cartilage conduction vibration source  825  so as to be enveloped circumferentially can provide cushioning against impact resulting from the rigid structure of the mobile telephone  801 , and can facilitate implementation in the mobile telephone  801 , which is constantly exposed to being dropped and other risks. The elastic body sandwiching the cartilage conduction vibration source  825  not only functions merely as a cushioning material, but also functions as a configuration for more effectively transmitting the vibration of the cartilage conduction vibration source  825  to the ear as described above, due to the fact that at least the outer elastic body is molded of a material having an acoustic impedance approximating that of ear cartilage. 
     Tenth Embodiment 
       FIG. 19  is a perspective view illustrating a tenth embodiment of the mobile telephone according to an aspect of the present invention. A mobile telephone  901  of the tenth embodiment, similarly with respect to that of the fourth embodiment, is an integrated type with no moving parts, and is configured as a “smartphone,” which has a large-screen display unit  205  provided with GUI functions. There is much in common with the structure thereof, and accordingly corresponding portions have been given like reference numerals as in the fourth embodiment, and a description has been omitted. However, similarly with respect to the fourth embodiment, the “upper part” in the tenth embodiment does not signify a separate upper part, but rather signifies the portion at the top of the integrated structure. 
     A point of difference in the tenth embodiment from the fourth embodiment lies in that a cartilage conduction vibration source  925 , which is made up of a piezoelectric bimorph element or the like, serves as the cartilage conduction vibration source, and also takes on the role of a drive source of the incoming-talk unit for generating sound waves that are transmitted to the tympanic membrane by air conduction. To provide a more specific description, the vibration conductor  227 , similarly with respect to the fourth embodiment, is in contact with the upper part of the cartilage conduction vibration source  925  and is arranged at the upper side of the mobile telephone. Furthermore, a cartilage conduction output unit  963 , which, similarly with respect to the seventh embodiment, is made using a material that has acoustic impedance approximating that of ear cartilage (a silicone rubber; a mixture of a silicone rubber and a butadiene rubber; a natural rubber; or; a structure formed using these varieties of rubber in which air bubbles are sealed), is arranged at the front of the cartilage conduction vibration source  925 . Because the cartilage conduction output unit  963 , as will be described later, serves as an incoming-talk unit for generating sound waves that are transmitted to the tympanic membrane by air conduction, the tenth embodiment has no special setting for the incoming-talk unit  13  as in the fourth embodiment. 
     Due to the configuration described above, first, the vibration of the cartilage conduction vibration source  925  is transmitted laterally by the vibration conductor  227 , causing the two ends  224  and  226  thereof to vibrate, and thus causing either one thereof to come into contact with the tragus allows sound to be heard by cartilage conduction. Also, similarly with respect to the fourth embodiment, the vibration conductor  227  vibrates not only at the right end  224  and left end  226  thereof but rather vibrates as a whole. Accordingly, it is possible in the tenth embodiment as well to transmit audio information regardless of where on the top inner edge of the mobile telephone  901  is contact made with the ear cartilage. Then, the vibration conductor  227  is in contact with the ear cartilage over a broad range and also the cartilage conduction output unit  963  is in contact with the tragus and other ear cartilage, when the mobile telephone  901  is brought up against the ear in such a form that a part of the cartilage conduction output unit  963  comes into the front of the entrance of the external auditory meatus, similarly with respect to an ordinary mobile telephone. Through such contact, sound can be heard by cartilage conduction. Similarly with respect to the fifth embodiment to the ninth embodiment, sound from the exterior of the cartilage conduction output unit  963 , which resonates in accordance with the vibration of the cartilage conduction vibration source  925 , is further transmitted to the tympanic membrane from the external auditory meatus as sound waves. Thus, the cartilage conduction output unit  963  can function as an incoming-talk unit by air conduction in the ordinary state of use of a mobile telephone. 
     Cartilage conduction conducts differently depending on the magnitude of force pushing on the cartilage; a more effective conduction state can be obtained when the pushing force is increased. This signifies that natural behavior, such as increasing the force pushing the mobile telephone against the ear when it is difficult to hear the incoming-talk unit sound, can be utilized to adjust the volume. Even when such a function is not explained to the user in, for example, the instruction manual, the user can still intuitively understand the function through natural behavior. Configuring the vibration of the cartilage conduction vibration source  925  in the tenth embodiment such that the vibration conductor  227 , which is a rigid body, and the cartilage conduction output unit  963 , which is an elastic body, can both simultaneously be in contact with the ear cartilage is intended to permit more effective volume adjustment primarily through adjusting the force pushing on the vibration conductor  227 , which is a rigid body. 
     The employment of the present invention is not to be limited to the above-described embodiments; other aspects can also benefit from the various above-described advantages of the present invention. For example, a resonator that is appropriate as a speaker other than the material having an acoustic impedance approaching that of ear cartilage can be arranged at the position where the cartilage conduction output unit  963  is arranged, in a case in which the tenth embodiment is configured such that the combination of the cartilage conduction vibration source  925  and the cartilage conduction output unit  963  function as a dedicated incoming-talk unit by air conduction. Such a case is also able to benefit from the features and advantages of the tenth embodiment, in which the cartilage conduction vibration source  925 , which is made up of a piezoelectric bimorph element or the like, serves as the cartilage conduction vibration source, and also serves as a drive source of the incoming-talk unit for generating sound waves that are transmitted to the tympanic membrane by air conduction. 
     Eleventh Embodiment 
       FIG. 20  is a perspective view illustrating an eleventh embodiment of the mobile telephone according to an aspect of the present invention. The mobile telephone  1001  of the eleventh embodiment, similarly with respect to that of the fourth embodiment, is an integrated type with no moving parts, and is configured as a “smartphone,” which has a large-screen display unit  205  provided with GUI functions. There is much in common with the structure thereof, and so corresponding portions have been given like reference numerals as in the fourth embodiment, and a description has been omitted. However, similarly with respect to the fourth embodiment, the “upper part” in the eleventh embodiment does not signify a separate upper part, but rather signifies the portion at the top of the integrated structure. 
     A point of difference in the eleventh embodiment from the fourth embodiment lies in that a right ear vibration unit  1024  and a left ear vibration unit  1026  are provided not to the front of the mobile telephone  1001  but rather to a side surface  1007  and to the side surface of the opposite side, shown without a reference number with relation to the diagrams, respectively (it shall be noted that the right ear vibration unit  1024  and the left ear vibration unit  1026  are arranged in a left-right reversal relative to the fourth embodiment of  FIG. 7 ). In a manner functionally similar to that of the fourth embodiment, the right ear vibration unit  1024  and the left ear vibration unit  1026  in the eleventh embodiment are also configured as the two end parts of the vibration conductor  1027 ; the cartilage conduction vibration source  1025 , which is made up of a piezoelectric bimorph element or the like, is arranged in contact with the lower part of the vibration conductor  1027 , the vibration thereof being transmitted to the vibration conductor  1027 . The vibration of the cartilage conduction vibration source  1025  is thereby transmitted laterally by the vibration conductor  1027 , causing the two ends  1024  and  1026  thereof to vibrate. The two ends  1024  and  1026  of the vibration conductor  1027  are provided so as to be in contact with the tragus when the upper end portion of a side surface (for example,  1007 ) of the mobile telephone  1001  is brought up against the ear. 
     A microphone or other outgoing-talk unit  1023  is provided to the lower surface of a mobile telephone  1001  such that audio uttered by the user can be picked up even in the state in which either of the right ear vibration unit  1024  or the left ear vibration unit  1026  is brought up against the tragus. In addition, the mobile telephone  1001  of the eleventh embodiment is provided with a speaker  1013  for videoconferencing functions occurring while the large-screen display unit  205  is being observed; the sensitivity of the microphone or other outgoing-talk unit  1023  is switched at the time of the videoconferencing function, and audio uttered by the user during the observation of the display monitor  205  can be picked up. 
       FIG. 21  is a side view of the mobile telephone  1001  illustrating the function of the right ear vibration unit  1024  and the left ear vibration unit  1026 ; the method illustrated is in accordance with  FIG. 2 . However, as depicted in  FIG. 20 , the right ear vibration unit  1024  and the left ear vibration unit  1026  in the eleventh embodiment are each provided to a side surface of the mobile telephone  1001 . Accordingly, in the eleventh embodiment, the side surface of the mobile telephone  1001  is brought up against the tragus, as depicted in  FIG. 21 , when the mobile telephone  1001  is brought up against the ear. In other words, it is not that the surface of the display unit  5  of the mobile telephone  1  is brought up against the tragus, as in  FIG. 2 ; therefore, the large-screen display unit  205  is not brought up against the ear and/or cheek and will not be fouled by sebum or the like. 
     More specifically,  FIG. 21A  illustrates the state in which the mobile telephone  1001  is held in the right hand and is brought up against the tragus  32  of the right ear  28 ; the side surface in view is the side opposite to the one in the mobile telephone  1001  being brought up against the right ear  28 , and the surface of the large-screen display unit  205  depicted by the cross-section is approximately perpendicular to the cheek and faces the lower rear of the face. The result is that, as described above, the large-screen display unit  205  is not brought up against the ear and/or cheek and does not get fouled with sebum or the like. Similarly,  FIG. 21B  illustrates the state in which the mobile telephone  1001  is held in the left hand and is brought up against the tragus  34  of the left ear  30 ; such a case is also similar to that of  FIG. 21A  in that, the large-screen display unit  205  being approximately perpendicular to the cheek and facing the lower rear of the face, the large-screen display unit  205  is not brought up against the ear and/or cheek and does not get fouled with sebum or the like. 
     However, such a state of use as in  FIG. 21  is implemented from the state in which the mobile telephone  1001  is held with the right hand and the large-screen display unit  205  is observed, for example, in the case of  FIG. 21A , by moving the mobile telephone  1001  without shaking the hand, and bringing the right ear vibration unit  1024  up against the tragus  32 . Accordingly, transitioning between the state of observing the large-screen display unit  205  and the state in which the right ear vibration unit  1024  is brought up against the tragus  32  is possible by a natural movement of the right hand, such as by slightly altering the angle between the elbow and the wrist, without needing to switch the hand holding the mobile telephone  1001  nor to shake the hand. To simplify the above description, the state in  FIG. 21  has the large-screen display unit  205  substantially perpendicular to the cheek, but the user can unrestrictedly select the angle of the hand or the posture for bringing the mobile telephone  1001  up against the ear; the angle of the large-screen display unit  205  with the cheek therefore need not be perpendicular, but rather may be moderately inclined. However, because each of the right ear vibration unit  1024  and the left ear vibration unit  1026  is provided to a side surface of the mobile telephone  1001  according to the configuration of the eleventh embodiment, the large-screen display unit  205  is not brought up against the ear and/or cheek and will not be fouled by sebum or the like, regardless of the posture in which the vibration units are brought up against the tragus  32  or  34 . 
     As a result of the fact that the large-screen display unit  205  is not hidden by facing the direction of the cheek in the eleventh embodiment, it is possible that the call destination or other display content may be seen by other people in front or rear. Accordingly, to protect privacy in the eleventh embodiment, a switch is automatically made from an ordinary display to a privacy-protection display (where, for example, nothing is displayed) in the state in which the right ear vibration unit  1024  or the left ear vibration unit  1026  is brought up against the ear. This point will be described in greater detail later. 
     Twelfth Embodiment 
       FIG. 22  is a perspective view illustrating a twelfth embodiment of the mobile telephone according to an aspect of the present invention.  FIG. 22A  illustrates the state in which a handle  1181  (to be described later) does not project out, and  FIG. 22B  illustrates the state in which the handle  1181  does project out. Similarly with respect to the eleventh embodiment, s cartilage conduction vibration unit  1124  of a mobile telephone  1101  of the twelfth embodiment is provided to a side surface of the mobile telephone  1101  (the side surface of the left side seen in  FIG. 22 , there being no reference numeral assigned thereto because the surface is hidden for convenience of illustration). The twelfth embodiment, being a mobile telephone, is based on an integrated type with no movable parts that is similar to the eleventh embodiment, and is configured as a “smartphone” having a large-screen display unit  205  provided with GUI functions. There is much in common with the structure thereof, and so corresponding portions have been given like reference numerals as in the eleventh embodiment, and a description has been omitted. However, similarly with respect to the eleventh embodiment, the “upper part” in the twelfth embodiment does not signify a separate upper part, but rather signifies the portion at the top of the integrated structure. 
     A point of difference in the twelfth embodiment from the eleventh embodiment lies in that, in addition to the configuration of the handle  1181  (to be described later), the cartilage conduction vibration unit  1124  is provided to one side surface on the left seen from  FIG. 22  in the mobile telephone  1101 . The element that is to be brought up against the ear is limited to being on the side surface of the left side, and therefore a microphone or other outgoing-talk unit  1123  is also provided to the lower surface close to the left side surface of the mobile telephone  1101 , as illustrated in  FIG. 22 . However, in the twelfth embodiment as well, the outgoing-talk unit  1123  is switched at the time of a videoconferencing function occurring while the large-screen display unit  205  is being observed, and audio uttered by the user as they observe the large-screen display unit  205  can be picked up. 
     In the twelfth embodiment, similarly with respect to the eleventh embodiment, the cartilage conduction vibration unit  1124  can be brought up against the tragus of the right ear from the state in which the large-screen display unit  205  is being viewed, as in  FIG. 22 . On the other hand, to bring the cartilage conduction vibration unit  1124  up against the tragus of the left ear, the holding hand can be switched such that the mobile telephone  1101  faces backwards, the cartilage conduction vibration unit  1124  thereby being made to face the left ear. Use in such a manner is also possible in the state in which the handle  1181  does not project out, as in  FIG. 22A . 
     The following is a description of the function of the handle. One natural way of holding when the cartilage conduction vibration unit  1124  is brought up against the ear at such an angle that the large-screen display unit  205  is approximately perpendicular to the cheek, as in  FIG. 21 , is embodied in a form such that the front surface of the mobile telephone  1101  on which the large-screen display unit  205  is provided and the back surface thereof are sandwiched by the thumb and the other four fingers, but the fingers at this time are in a state of touching the large-screen display unit  205 ; therefore, a concern is presented in that a mistaken operation is possible and the comparatively long-term and powerful contact during a call will result in fingerprint fouling. 
     In view whereof, to prevent the fingers from touching the large-screen display unit  205  while also facilitating holding the mobile telephone  1101 , the twelfth embodiment is configured such that the handle  1181  projects out from the state in  FIG. 22A  to the state in  FIG. 22B  according to need, it being possible to use the handle  1181  to hold the mobile telephone. It thereby becomes possible in the state represented in  FIG. 22B  to sandwich the handle  1181  and the end parts of the body of the mobile telephone  1101  with the thumb and the other four fingers, and the mobile telephone  1101  can be readily held without the large-screen display unit  205  being touched. The handle  1181  can also be grasped to hold the mobile telephone  1101  in a case in which the degree of projection is configured so as to be comparatively larger. However, similarly with respect to the case of the state in  FIG. 22A , the mobile telephone  1101  can also be held so as to face backwards, the cartilage conduction vibration unit  1124  thereby being brought up against the tragus of the left ear. 
     To cause the handle  1181  to project out from the state in  FIG. 22A , a projection operation button  1183  is pushed and the handle is thereby unlocked and projects slightly outward; the state in  FIG. 22B  can therefore be achieved by pulling the handle out. Because the lock is engaged in the state in  FIG. 22B , no problems are presented even when the handle  1181  is held and the cartilage conduction vibration unit  1124  is pushed up against the tragus. To house the handle  1181 , the lock is undone when the projection operation button  1183  is pushed in the state in  FIG. 22B ; therefore, the lock is engaged when the handle  1181  is pushed in so as to assume the state in  FIG. 22A . 
       FIG. 23  is a flow chart of the operation of the controller  239  (borrowing from  FIG. 8 ) in the twelfth embodiment of  FIG. 22 . However, parts that the flow of  FIG. 23  shares with the flow of  FIG. 14  have been given like step reference numerals, and a description thereof has been omitted.  FIG. 23  also illustrates an abstraction of the operation that focuses on related functions, in order to primarily provide a description of the function of the cartilage conduction vibration unit  228 . Accordingly, similarly with respect to  FIG. 14  and the like, the controller  239  in the twelfth embodiment also contains typical mobile telephone functions and other operations not represented by the flow of  FIG. 23 .  FIG. 23  uses boldface print to illustrate points of difference with  FIG. 14 , and thus the following description focuses on these portions. 
     In the flow of  FIG. 23 , there is performed a check for whether there has been an operation to initiate a call once step S 104  is reached. A case in which there has not been an operation moves directly on to step S 34 . On the other hand, in a case in which an operation to initiate a call is detected, the flow proceeds to step S 132 , in which there is performed a check for whether the handle  1181  is in state of projecting. Then, in a case of the handle not being in a state of projecting out, the flow proceeds to step S 134 , in which there is performed a check for whether the cartilage conduction vibration unit  1124  is in a state of being in contact with the ear cartilage. Then, in a case in which a state of contact is detected, the flow proceeds to step S 136 . However, in a case in which it is detected in step S 132  that the handle  1181  is in a state of projecting out, the flow moves directly on to step S 136 . 
     In step S 136 , the outgoing-talk unit  1123  is turned on, and in step S 138 , the cartilage conduction vibration unit  1124  is turned on. On the other hand, the speaker  1013  is turned off in step S 140 . Subsequently, proceeding on to step S 142 , the display of the large-screen display unit  205  is set to a privacy-protection display. The privacy-protection display is a state in which either there is a predetermined display that does not contain private information, or nothing is displayed at all. At this point in time, only the display content is altered, without the large-screen display unit  205  itself being turned off. After the display has been controlled in such a manner, the flow moves on to step S 52 . A case in which the desired state already exists in step S 136  to S 142  leads to step S 52  without anything being done in these steps as a result. 
     On the other hand, in a case in which there is no detection in step S 134  that the cartilage conduction vibration unit  1124  is in a state of being in contact with the ear cartilage, the flow moves on to step S 144 , which turns the outgoing-talk unit  1123  on; in step S 146 , the cartilage conduction vibration unit  1124  is turned off. Meanwhile, the speaker  1013  is turned on in step S 148 . Subsequently, the flow proceeds to step S 150 , and the display of the large-screen display unit  205  is set to an ordinary display. After the display has been controlled in such a manner, the flow moves on to step S 118 . A case in which the desired state already exists in step S 144  to S 150  also leads to step S 118 , without anything being done in these steps as a result. 
     Steps S 52  to S 56 , step S 118 , and step S 34 , which follow step S 142 ; as well as step S 118  and step S 34 , which follow step S 150 , are shared with  FIG. 14 , and a description thereof has thereof been omitted. Upon moving on to step S 118 , there is performed a check for whether the call state has been cut off; in a case in which no call state interruption is detected, the flow returns to step S 132 , following which steps S 132  to S 150  and steps S 52  to S 56  are repeated. Switching between the cartilage conduction vibration unit  1124  and the speaker  1013  and also switching the display are thereby performed automatically, either by moving the handle  1181  in or out or by the contact or non-contact of the cartilage conduction vibration unit  1124 . In the state in which the cartilage conduction vibration unit  1124  has been turned on, switching occurs automatically between whether or not the waveform inversion signal of one&#39;s own voice is added, which is based on the presence or absence of the earplug bone conduction effect. 
     In the repetition of the aforementioned steps, there may be an insertion in between steps S 142  and S 52  of a step for determining whether a predetermined period of time has passed after the display of the large-screen display unit  205  is initially changed to the privacy-protection display in step S 142 , and also of a step for turning the large-screen display unit  205  itself off with the purpose of saving electricity when the predetermined period of time has passed. At this time, in accordance therewith, there is an insertion in between steps S 148  and S 150  of a step for turning the large-screen display unit  205  on when same has been turned off. The flow in  FIG. 23  can also be used for the eleventh embodiment in  FIG. 20  by the omission of step S 132 . 
     Thirteenth Embodiment 
       FIG. 24  is a perspective view illustrating a thirteenth embodiment of the mobile telephone according to an aspect of the present invention.  FIG. 24A  illustrates a state in which an incoming/outgoing-talk unit  1281  (to be described later) is integrated with a mobile telephone  1201 , and  FIG. 24B  illustrates a state in which the incoming/outgoing-talk unit  1281  is separated. The mobile telephone  1201  of the thirteenth embodiment assumes a state in which a cartilage conduction vibration unit  1226  is arranged on the side surface  1007  of the mobile telephone  1201  in the state in  FIG. 24A . This is a point of similarity with the eleventh and twelfth embodiments. The thirteenth embodiment, being a mobile telephone, is based on an integrated type with no movable parts that is similar to the eleventh embodiment and the twelfth embodiment, and is configured as a “smartphone” having a large-screen display unit  205  provided with GUI functions. There is much in common with the structure thereof, and so corresponding portions have been given like reference numerals as in the twelfth embodiment, and a description has been omitted. However, similarly with respect to the eleventh embodiment and the twelfth embodiment, the “upper part” in the thirteenth embodiment does not signify a separate upper part, but rather signifies the portion at the top of the integrated structure. 
     The thirteenth embodiment has a similar configuration to that of  FIG. 22A  of the twelfth embodiment, except in that, in the state in  FIG. 24A , the cartilage conduction vibration unit  1226  and an outgoing-talk unit  1223  are arranged on the right when seen from  FIG. 24 . However, the cartilage conduction vibration unit  1226  is brought up against the tragus of the left ear from the state in which the large-screen display unit  205  is being viewed, as in  FIG. 24 . Then, to bring the cartilage conduction vibration unit  1226  up against the tragus of the right ear, the holding hand is switched such that the mobile telephone  1201  faces backwards, whereby the cartilage conduction vibration unit  1226  is made to face the left ear. 
     A point of difference in the thirteenth embodiment from the twelfth embodiment lies in that the incoming/outgoing-talk unit  1281 , which comprises the cartilage conduction vibration unit  1226  and the outgoing-talk unit  1223 , can be separated from the mobile telephone  1201 , as in  FIG. 24B . The incoming/outgoing-talk unit  1281  can be inserted into and released from the mobile telephone  1201  by the operation of an insertion/release locking button  1283 . The incoming/outgoing-talk unit  1281  further possesses an incoming/outgoing-talk operation unit  1209 , and also a controller  1239  for the cartilage conduction vibration unit  1226  and the outgoing-talk unit  1223 , the controller comprising a power supply unit. The incoming/outgoing-talk unit  1281  also possesses a Bluetooth™ or other short-range communication unit  1287 , which is capable of wireless communication with the mobile telephone  1201  using radio waves  1285 ; the user&#39;s voice, which is picked up from the outgoing-talk unit  1223 , and also information on the state of the contact of the cartilage conduction vibration unit  1226  with the ear are sent to the mobile telephone  1201 , and the cartilage conduction vibration unit  1226  vibrates on the basis of the audio information received from the mobile telephone  1201 . 
     The incoming/outgoing-talk unit  1281  separated out in the manner described above functions as a pencil incoming/outgoing-talk unit; the cartilage conduction vibration unit  1226  is held unrestrictedly and brought into contact with the tragus of either the right ear or the left ear, whereby a call can take place. Increasing the contact pressure on the tragus can yield the ear plug bone conduction effect. The incoming/outgoing-talk unit  1281  being in the separated state, sound can be heard by air conduction even when either the surface around the long axis of the cartilage conduction vibration unit  1226  or the tip thereof is brought up against the ear. In addition to the method for using the incoming/outgoing-talk unit  1281 , in which the incoming/outgoing-talk unit ordinarily is housed in the mobile telephone  1201  as in  FIG. 24A  and is then separated out as appropriate like in  FIG. 24B , there is also a possible method for using the incoming/outgoing-talk unit such that, in the separated state as in  FIG. 24B , for example, the mobile telephone  1201  being housed in an inner pocket or bag and the incoming/outgoing-talk unit  1281  being inserted into an outer breast pocket like a pencil, only the incoming/outgoing-talk unit  1281  is used for operation and for calls to take place when outgoing and incoming calls are made. The cartilage conduction vibration unit  1226  can also function as a vibrator for incoming calls. 
     A pencil incoming/outgoing-talk unit  1281  such as in the thirteenth embodiment is not to be limited to the case of comprising a combination with a specialized mobile telephone  1201  having a housing unit. For example, a configuration as an accessory of a typical mobile telephone having a short-range communication function using Bluetooth™ or the like is also possible. 
     Fourteenth Embodiment 
       FIG. 25  is a perspective view illustrating a fourteenth embodiment of the mobile telephone according to an aspect of the present invention.  FIG. 25A  illustrates the state in which an incoming/outgoing-talk unit  1381  (to be described later) is housed in a mobile telephone  1301 , and  FIG. 25B  illustrates the state in which the incoming/outgoing-talk unit  1381  is pulled out. The mobile telephone  1301  of the fourteenth embodiment assumes a state in which a cartilage conduction vibration unit  1326  is arranged on the side surface  1007  of the mobile telephone  1301  in the state in  FIG. 25A . This is a point of similarity with the eleventh to thirteenth embodiments. The fourteenth embodiment, being a mobile telephone, is based on an integrated type with no movable parts that is similar to the eleventh to thirteenth embodiments, and is configured as a “smartphone” having a large-screen display unit  205  provided with GUI functions. There is much in common with the structure thereof, and so corresponding portions have been given like reference numerals as in the thirteenth embodiment, and a description has been omitted. However, similarly with respect to the eleventh to thirteenth embodiments, the “upper part” in the fourteenth embodiment does not signify a separate upper part, but rather signifies the portion at the top of the integrated structure. 
     The fourteenth embodiment, in the state in  FIG. 25A , also has a similar configuration to that of  FIG. 24A  of the thirteenth embodiment. A point of difference in the fourteenth embodiment from the thirteenth embodiment lies in that, as illustrated in  FIG. 25B , the incoming/outgoing-talk unit  1381  has a wired connection with the mobile telephone  1301  rather than a wireless one. Similarly with respect to the thirteenth embodiment, the incoming/outgoing-talk unit  1381  can be inserted into and released from the mobile telephone  1301  by the operation of the insertion/release locking button  1283 . The incoming/outgoing-talk unit  1381  has a cable  1339  for respectively connecting the cartilage conduction vibration unit  1326  with the outgoing-talk unit  1323 , and also the outgoing-talk unit  1323  with the mobile telephone  1301 . In the housed state in  FIG. 25A , the portion of the cable  1339  that is between the cartilage conduction vibration unit  1326  and the outgoing-talk unit  1323  is housed in a groove of the side surface  1007 , and the portion thereof that is between the outgoing-talk unit  1323  and the mobile telephone  1301  is automatically wound up within the mobile telephone  1301  by a spring when the outgoing-talk unit  1323  is housed. The outgoing-talk unit  1323  is also provided with a remote control operation unit for operating at the time of outgoing and incoming calls. In the manner described above, in the fourteenth embodiment, the user&#39;s voice, which is picked up from the outgoing-talk unit  1323 , and also information on the state of the contact of the cartilage conduction vibration unit  1326  with the ear are transmitted to the mobile telephone  1301  by wire, and the cartilage conduction vibration unit  1326  vibrates on the basis of the audio information received by wire from the mobile telephone  1301 . 
     The incoming/outgoing-talk unit  1381  pulled out as in  FIG. 25B  is used by being hooked onto the cartilage of the lower part of the entrance to the external auditory meatus such that the portion of the cartilage conduction vibration unit  1326  is in contact with the tragus. Then, the outgoing-talk unit  1323  in this state is located close to the mouth, and can therefore pick up the user&#39;s voice. Holding the portion of the cartilage conduction vibration unit  1326  and increasing the contact pressure on the tragus can yield the ear plug bone conduction effect. In addition to the method for using the incoming/outgoing-talk unit  1381  in which the incoming/outgoing-talk unit ordinarily is housed in the mobile telephone  1301  as in  FIG. 25A  and is then pulled out as appropriate like in  FIG. 25B , there is also a possible method for using the incoming/outgoing-talk unit such that, in the state in which the incoming/outgoing-talk unit  1381  is pulled out as in  FIG. 25B , for example, the mobile telephone  1301  remains housed in an inner pocket or the like and the cartilage conduction vibration unit  1326  of the incoming/outgoing-talk unit  1381  remains hooked on the ear. The cartilage conduction vibration unit  1326  can also function as a vibrator for incoming calls, similarly with respect to the thirteenth embodiment. 
     A wired earphone-type incoming/outgoing-talk unit  1381  such as in the fourteenth embodiment is not to be limited to the case of comprising a combination with a specialized mobile telephone  1301  having a housing unit. For example, a configuration as an accessory of a typical mobile telephone having an external earphone-microphone connection terminal is also possible. 
     The various features indicated in each of the embodiments described above are not necessarily specific in each case to an individual embodiment; the features of each of the embodiments can be combined or rearranged with the features of other embodiments as appropriate, wherever it is possible to make use of the advantages thereof. 
     The implementation of the variety of features indicated in each of the embodiments described above is not to be limited to the above embodiments; the features can be implemented in other embodiments as well, wherever it is possible to benefit from the advantages thereof. For example, arranging the cartilage conduction vibration unit on the side surface relative to the display surface in the eleventh to fourteenth embodiments, being a configuration in which audio information is transmitted from the tragus by cartilage conduction, can thereby facilitate contact with the tragus and use the tragus as a conduction point for sound information. It is accordingly possible to achieve a listening posture free of discomfort, and approximating that of a conventional telephone in which one listens using the ear. The transmission of audio by cartilage conduction also does not require the formation of a closed space at the front of the entrance to the external auditory meatus, as is the case with air conduction, and is therefore appropriate for arrangement on the side surface. Furthermore, because audio information is conducted by cartilage conduction, there is a low percentage of air conduction caused by the vibration of the vibrator, and sound can be transmitted to the user&#39;s external auditory meatus without substantial sound leakage to the exterior, even though the cartilage conduction vibration unit is arranged on the side surface of the mobile telephone, which is narrow. This is due to the fact that, in cartilage conduction, sound does not enter the external auditory meatus as air conduction sound but rather is transmitted due to the contact of the sound energy with the cartilage, the sound being generated thereafter inside the external auditory meatus by the vibration of the tissue in the ear. Accordingly, the utilization of the cartilage conduction vibration unit in the eleventh to fourteenth embodiments is also very effective when a sound information output unit is arranged on the side surface relative to the display surface, there being no concern that the incoming-talk unit sound will be heard by neighboring people due to sound leakage, which would be annoying, nor that any sensitive information will be leaked. 
     However, from the standpoint of benefiting from the advantage of being able to prevent the display surface from being fouled by contact with the ear and/or cheek when audio information is being listened to, the arrangement on the side surface relative to the display surface is not to be limited to a case in which the audio information output unit that is to be arranged is the cartilage conduction vibration unit. For example, the configuration may be such that the audio information output unit is an earphone that works by air conduction, the earphone being provided to the side surface relative to the display surface. The configuration may also be such that the audio information output unit is a bone conduction vibration unit hitting against a bone at the front of the ear (the zygomatic arch), a bone at the rear of the ear (the mastoid part), or the forehead, the unit being arranged on the side surface relative to the display surface. Due to the arrangement on the side surface relative to the display surface, the display surface will not be in contact with the ear and/or cheek when audio information is being listened to; therefore, even in cases where these audio information output units are used, advantages can also accrue in regard to being able to prevent fouling of the display surface. In cases in which such units are used, moreover, a microphone can be arranged on the side surface relative to the display surface in a case in which the arrangement of the earphone and/or bone conduction vibration unit is limited to one side surface, as in the twelfth to fourteenth embodiments. Similarly with respect to the eleventh to fourteenth embodiments, when the earphone is brought up against the ear for a call in a posture such as is represented in  FIG. 21 , or, alternatively, when the bone conduction vibration unit is held to a bone at the front or rear of the ear for a call, setting the display surface to a privacy-protection display makes it possible to prevent a display containing private information from being viewed by other people, either in the front or rear or to the left or right. 
     Fifteenth Embodiment 
       FIG. 26  is a diagram of the system of a fifteenth embodiment according to an aspect of the present invention. The fifteenth embodiment is configured as an incoming/outgoing-talk unit for a mobile telephone, and forms a mobile telephone system together with a mobile telephone  1401 . The fifteenth embodiment takes the configuration of a system in common with the configuration of the system in the state in which the incoming/outgoing-talk unit  1281  is separated from the mobile telephone  1201 , as in  FIG. 24B  in the thirteenth embodiment; therefore, portions that are in common have been given like reference numerals, a description thereof being omitted unless there is a particular need. The mobile telephone  1401 , similarly with respect to the mobile telephone  1201  of the thirteenth embodiment, is not to be limited to the case of being specially configured to be used in combination with an incoming/outgoing-talk unit; rather, the case may also be one of a configuration as a typical mobile telephone having, for example, a short-range communication function using Bluetooth™ or the like. The incoming/outgoing-talk unit in such a case then assumes a configuration as an accessory of such a typical mobile telephone  1401 , similarly with respect to the thirteenth embodiment. A more detailed description of these two cases will be provided later. 
     A point of difference in the fifteenth embodiment from the thirteenth embodiment lies in that the incoming/outgoing-talk unit is configured as a headset  1481 , rather than in a pencil-type format such as in the thirteenth embodiment. The incoming/outgoing-talk unit  1481  conforms with the thirteenth embodiment in being provided with an outgoing-talk unit  1423  and a cartilage conduction vibration unit  1426  comprising a piezoelectric bimorph element; in being provided with a controller  1439 , which comprises a power supply unit for the cartilage conduction vibration unit  1426  and the outgoing-talk unit  1423 ; and in being provided with the incoming/outgoing-talk operation unit  1409 . The incoming/outgoing-talk unit  1481  further conforms with the thirteenth embodiment in being provided a short-range communication unit  1487  compliant with Bluetooth™ or another scheme and capable of wireless communication with the mobile telephone  1401  using radio waves  1285 ; in sending to the mobile telephone  1401  the user&#39;s voice, which is picked up from the outgoing-talk unit  1423 , and also information on the state of the contact made by the cartilage conduction vibration unit  1426  with the ear; and in causing the cartilage conduction vibration unit  1426  to vibrate on the basis of the audio information received from the mobile telephone  1401 . 
     There shall next be provided a description of the configuration specific to the fifteenth embodiment. The headset  1481  is attached to the right ear  28  by an ear-hooking unit  1489 . The headset  1481  is provided with a movable unit  1491  that is held by an elastic body  1473 , and the cartilage conduction vibration unit  1426  is held by the movable unit  1491 . The configuration is such that the cartilage conduction vibration unit  1426  is in contact with the tragus  32  in the state in which the headset  1481  is attached to the right ear  28  by the ear-hooking unit  1489 . The elastic body  1473  makes it possible to bend the movable unit  1491  in the direction of the tragus  32 , and also functions as a cushioning material for the cartilage conduction vibration unit  1426 , protecting the cartilage conduction vibration unit  1426  against mechanical impact due to the headset  1481 . 
     Sound information can be listened to via ordinary cartilage conduction in the state in  FIG. 26 . However, when listening comprehension of sound information is impaired due to environment noise, the movable unit  1491  is pushed from the exterior and thereby bent, and the pressure contact of the cartilage conduction vibration unit  1426  on the tragus  32  is increased, whereby the tragus  32  is made to block the hole of the ear. The ear plug conduction effect, which has also been described in the other embodiments, can thereby be generated, and even louder audio information can be transmitted. Obstructing the hole of the ear with the tragus  32  further allows environment noise to be blocked. Information on one&#39;s own voice, which is picked up from the outgoing-talk unit  1423 , is also subjected to phase inversion on the basis of the mechanical detection of the bent state of the movable unit  1491 , and is then transmitted to the cartilage conduction vibration unit  1426 , to cancel out one&#39;s own voice. A more detailed description of the merits or other advantageous attributes thereof has been described in the other embodiments, and thus has been omitted. 
     Sixteenth Embodiment 
       FIG. 27  is a diagram of the system of a sixteenth embodiment according to an aspect of the present invention. The sixteenth embodiment is also configured as a headset  1581  for creating an incoming/outgoing-talk unit for the mobile telephone  1401 , similarly with respect to the fifteenth embodiment, and forms a mobile telephone system together with the mobile telephone  1401 . The sixteenth embodiment has much in common with the fifteenth embodiment, and therefore parts that are in common have been given like reference numerals, and a description thereof has been omitted unless there is a particular need. The mobile telephone  1401 , as has been described in the fifteenth embodiment, may in some cases have a special configuration, and may in other cases be configured as a typical mobile telephone. A description of these two cases will be provided later. 
     A point of difference in the sixteenth embodiment from the fifteenth embodiment lies in that the entirety of a movable unit  1591  is made using an elastic material that has acoustic impedance approximating that of ear cartilage (a silicone rubber; a mixture of a silicone rubber and a butadiene rubber; a natural rubber; or a structure formed using these varieties of rubber in which air bubbles are sealed). A cartilage conduction vibration unit  1526 , which comprises a piezoelectric bimorph element or the like, is embedded inside the movable unit  1591 , similarly with respect to the eighth embodiment. Such a configuration allows the movable unit  1591 , including the cartilage conduction vibration unit  1526 , to be bent toward the tragus  32  under its own elasticity. Although omitted from the diagrams for simplicity, the circuit portions of the cartilage conduction vibration unit  1526 , the controller  1439 , and the like are connected by a connection wire similar to the flexible connection wire  769  in  FIG. 17C . 
     In the sixteenth embodiment, the movable unit  1591  is in contact with the tragus  32  in the state represented in  FIG. 27 ; sound information from the cartilage conduction vibration unit  1526  is conducted to the tragus  32  by cartilage conduction via the elastic material of the moveable unit  1591 . The benefits from such a configuration are similar to those described in the fifth to tenth embodiments. Furthermore, when listening comprehension of sound information is impaired due to environment noise, the movable unit  1591  is pushed from the exterior and thereby bent, and the pressure contact of the cartilage conduction vibration unit  1526  on the tragus  32  is increased, whereby the tragus  32  is made to block the hole of the ear. The ear plug conduction effect can thereby be generated, and even louder sound information can thereby be transmitted, similarly with respect to the fifteenth embodiment. The fact that environment noise can be blocked by the obstruction of the hole of the ear by the tragus  32  is also similar to the fifteenth embodiment. Another similarity with the fifteenth embodiment is the fact that information on one&#39;s own voice, which is picked up from the outgoing-talk unit  1423 , can also be subjected to phase inversion on the basis of the mechanical detection of the bent state of the movable unit  1591  and then transmitted to the cartilage conduction vibration unit  1526  to cancel out one&#39;s own voice. 
     Furthermore, in the sixteenth embodiment, because the cartilage conduction vibration unit  1526  is embedded inside the movable unit  1591 , the elastic material constituting the movable unit  1591  functions as a cushioning material for protecting the cartilage conduction vibration unit  1526  against mechanical impact to the headset  1581  and also for further protecting the cartilage conduction vibration unit  1526  against mechanical impact to the movable unit  1591  itself. 
       FIG. 28  is a block diagram of the sixteenth embodiment, identical portions being given identical reference numerals to those in  FIG. 27 . Also, because the configuration of the block diagram has many portions in common with the fourth embodiment, corresponding portions are each assigned the same reference numerals as each respective part. Also, a description has been omitted for these identical or shared portions, unless there is a particular need. In the sixteenth embodiment, the incoming-talk-processing unit  212  and the earphone  213  in  FIG. 28  correspond to the incoming-talk unit  13  in  FIG. 27 , and the outgoing-talk-processing unit  222  and the microphone  223  in  FIG. 28  correspond to the outgoing-talk unit  23  in  FIG. 27 . Similarly with respect to the fourth embodiment, the outgoing-talk-processing unit  222  transmits a part of the audio from the operator picked up by the microphone  223  to the incoming-talk-processing unit  212  as sidetone, and the incoming-talk-processing unit  212  superimposes the operator&#39;s own sidetone onto the voice of the calling party from the telephone communication unit  47  and outputs same to the earphone  213 , whereby the balance between the bone conduction and air conduction of one&#39;s own voice in the state in which the mobile telephone  1401  is brought up against an ear is made to approximate a natural state. 
     A point of difference in the block diagram of the sixteenth embodiment in  FIG. 28  from the block diagram of the fourth embodiment in  FIG. 8  lies in that the mobile telephone  301  of the fourth embodiment in  FIG. 8  is divided in the sixteenth embodiment of  FIG. 28  into the mobile telephone  1401  and the headset  1581  for creating the incoming/outgoing-talk unit. Specifically,  FIG. 28  corresponds to a block diagram of the case in the sixteenth embodiment in which the mobile telephone  1401  is specially configured to be used in combination with the headset  1581 . 
     More specifically, in  FIG. 28 , the output of the phase adjustment mixer unit  236  is wirelessly sent externally by a short-range communication unit  1446  using Bluetooth™ or the like. The short-range communication unit  1446  also inputs audio signals received wirelessly from an external microphone into the outgoing-talk-processing unit  222 . Furthermore, although a depiction and description has been omitted in the other embodiments,  FIG. 28  depicts a power supply unit  1448 , which has a storage battery for supplying power to the entire mobile telephone  1401 . 
     On the other hand, the configuration of the headset  1581  has a short-range communication unit  1487  for intercommunication with the short-range communication unit  1446  of the mobile telephone  1401  using radio waves  1285 , and also has a power supply unit  1548  for supplying power to the entire headset  1581 . The power supply unit  1548  supplies power by a replaceable battery or by a built-in storage battery. The controller  1439  of the headset  1581  wirelessly sends audio picked up from the outgoing-talk unit (microphone)  1423  to the mobile telephone  1401  from the short-range communication unit  1487 , and also controls the drive of the cartilage conduction vibration unit  1526  on the basis of audio information that has been received by the short-range communication unit  1487 . Furthermore, the controller  1439  transmits an operation to receive an incoming call or to send an outgoing call, which is performed by the operation unit  1409 , to the mobile telephone  1401  from the short-range communication unit  1487 . A bending detection unit  1588  mechanically detects the bent state of the movable unit  1591 , and the controller  1439  transmits the bending detection information from the short-range communication unit  1487  to the mobile telephone  1401 . The bending detection unit  1588  can comprise, for example, a switch that is turned on mechanically when the bending reaches or exceeds a predetermined angle. The controller  239  of the mobile telephone  1401  controls the phase adjustment mixer unit  236  on the basis of the bending detection information received by the short-range communication unit  1446 , and determines whether or not to add, to the audio information from the incoming-talk-processing unit  212 , the signal of the waveform inverter  240  that is based on one&#39;s own voice transmitted from the outgoing-talk unit (microphone)  1423  to the outgoing-talk-processing unit  222 . 
     Seventeenth Embodiment 
       FIG. 29  is a block diagram of the case in which, in the sixteenth embodiment of  FIG. 27 , the mobile telephone  1401  is configured as a typical mobile telephone, and the headset  1581  is configured as an accessory thereof; the diagram serves to provide a description as the seventeenth embodiment in order to avoid confusion with  FIG. 28 . The configuration of  FIG. 29  has much in common with  FIG. 28 , and therefore identical parts have been given reference numerals identical to those in  FIG. 28 , a description thereof having been omitted unless there is a particular need. 
     As described above, the mobile telephone  1601  in the seventeenth embodiment in  FIG. 29  is configured as a typical mobile telephone comprising a short-range communication function using Bluetooth™ or the like. Specifically, the short-range communication unit  1446  inputs to the outgoing-talk-processing unit  222  audio information from an external microphone that is similar to what is inputted from the microphone  223 , and also externally outputs audio information that is similar to what is outputted to the earphone  213 . The controller  239  is used to switch the audio information that is inputted from and outputted to external elements through the short-range communication unit  1446  relative to the internal microphone  223  and earphone  213 . As described above, in the seventeenth embodiment of  FIG. 29 , the functions of the acoustics adjustment unit  238 , the waveform inverter  240 , and the phase adjustment mixer unit  236  in the sixteenth embodiment in  FIG. 28  are transferred to the headset  1681 . 
     In accordance therewith, the configuration of the headset  1681  in the seventeenth embodiment of  FIG. 29  differs from that of the sixteenth embodiment in  FIG. 28  on the following points. The configuration is such that, although listening audio information received using the short-range communication unit  1487  by the control of a controller  1639  of the headset  1681  is inputted to the phase adjustment mixer unit  1636 , audio information from the waveform inverter  1640  can also additionally be inputted thereto. Also, according to need, the phase adjustment mixer unit  1636  mixes the audio information from the waveform inverter  1640  into the received listening audio information and drives a cartilage conduction vibration unit  1626 . More specifically, a part of the audio from the operator that has been picked up by the outgoing-talk unit (microphone)  1423  is inputted to the acoustics adjustment unit  1638 , and the acoustics of one&#39;s own voice to be transmitted to the cochlea from a cartilage conduction vibration unit  1628 , which comprises the cartilage conduction vibration unit  1626 , are adjusted to acoustics approximating the operator&#39;s own voice transmitted to the cochlea by conduction in the body from the vocal cords when the ear plug bone conduction effect is generated, and the two are effectively canceled out. The waveform inverter  1640  subjects one&#39;s own voice, which has undergone acoustic adjustment in this manner, to waveform inversion, and outputs the same according to need to the phase adjustment mixer unit  1636 . 
     The mixing control shall now be described in detail. When the bending of the movable unit  1591  detected by the bending detection unit  1588  reaches or exceeds a predetermined angle and a state is in effect in which the hole of the ear is obstructed by the tragus, which is pushed thereby, the phase adjustment mixer unit  1636  mixes the output from the waveform inverter  1640  and drives the cartilage conduction vibration unit  1628 , depending on an instruction from the controller  1639 . The excessive amount of one&#39;s own voice that occurs during the earplug bone conduction effect is thereby cancelled out, thus easing the discomfort. At this time, the degree of cancellation is regulated such that an amount of one&#39;s own voice equivalent to the sidetone remains without being cancelled out. On the other hand, when the bending detection unit  1588  does not detect a predetermined or greater amount of bending, the state in effect is one in which the hole of the ear is not obstructed by the tragus and the earplug bone conduction effect is not created; therefore, the phase adjustment mixer unit  1636  does not mix the waveform inversion output of one&#39;s own voice from the waveform inverter  1640 , on the basis of an instruction from the controller  1639 . Similarly with respect to the fourth embodiment, the configuration of the seventeenth embodiment of  FIG. 29  may invert the positions of the acoustics adjustment unit  1638  and the waveform inverter  1640 . Furthermore, the acoustics adjustment unit  1638  and the waveform inverter  1640  may be integrated as a function within the phase adjustment mixer unit  1636 . It is a point of similarity with the sixteenth embodiment that the controller  1639  transmits an operation to receive an incoming call or to send an outgoing call, which is performed by the operation unit  1409 , to the mobile telephone  1601  from the short-range communication unit  1487 . 
     The block diagrams in  FIGS. 28 and 29  can be applied not only to the configuration of the system diagram in  FIG. 27 , but also the system diagram of the fifteenth embodiment in  FIG. 26 . They can also be applied to the thirteenth embodiment of  FIG. 24  and the fourteenth embodiment of  FIG. 25  when the bending detection unit  1588  is read as the pressure sensor  242  as in  FIG. 8 . However, in the case of a reading as the thirteenth embodiment, in the case in which the incoming/outgoing-talk unit  1281  is incorporated into the mobile telephone  1201  as in  FIG. 24A , a contact unit for directly connecting the two is provided to the mobile telephone  1201  and the incoming/outgoing-talk unit  1281 . In the state in  FIG. 24A , the wireless communication exchange between the mobile telephone  1201  and the incoming/outgoing-talk unit  1281  by a short-range communication unit is automatically switched to communication via such a contact unit. In the case of a reading as the fourteenth embodiment, a connector contact for establishing a wired connection between the two is provided to the mobile telephone  1301  and the incoming/outgoing-talk unit  1381  instead of the short-range communication unit. 
       FIG. 30  is a flow chart of the operation of the controller  1639  of the headset  1681  in the seventeenth embodiment of  FIG. 29 . The flow in  FIG. 30  starts when the primary power supply is turned on by the operation unit  1409 ; in step S 162 , there is performed a check for initial startup and for the functions of each unit. Next, in step S 164 , there is an instruction for a short-range communication connection with the mobile telephone  1601 , and the flow moves on to step S 166 . When a short-range communication is established on the basis of the instruction in step S 164 , the headset  1681  enters a state of constant connection with the mobile telephone  1601  unless the primary power supply is subsequently turned off. In step S 166 , there is performed a check for whether short-range communication with the mobile telephone  1601  has been established; the flow moves on to step S 168  when establishment is confirmed. 
     In step S 168 , there is performed a check for whether or not an incoming signal from the mobile telephone  1601  has been transmitted through a short-range communication. Then, when there is an incoming signal, the flow proceeds to step S 170 , in which a drive is performed such that the cartilage conduction vibration unit  1626  has an incoming signal vibration. This incoming signal vibration may have an audible frequency, or may vibrate in a low frequency region with a large enough amplitude that the vibration can be felt with the tragus  32 . Next, in step S 172 , there is performed a check for whether an incoming signal has been stopped by an outgoing call stop operation or the like from the party making the call; when there is no stop, the flow proceeds to step S 174 , in which there is performed a check for whether there has been a receiving operation by the operation unit  1409 . Then, when there is a receiving operation, the flow moves on to step S 176 . On the other hand, when there is no receiving operation in step S 174 , the flow returns to step S 170 , following which a loop of steps S 170  to S 174  is repeated unless either the incoming signal vibration of the cartilage conduction vibration unit  1626  is stopped or a receiving operation is performed. 
     On the other hand, in a case in which no incoming signal is detected in step S 168 , the flow moves on to step S 178 , in which there is performed a check for whether there has been a one-touch outgoing call operation to a registered call destination by the operation unit  1409 . The flow proceeds to step S 180  when an outgoing call operation is detected; the outgoing call operation is transmitted to the mobile telephone  1601  to make an outgoing call, and there is performed a check for whether or not a signal to the effect that a call connection has been established by a response from the other party thereto has been transmitted from the mobile telephone  1601 . When it is confirmed that a call connection has been established in step S 180 , the flow moves on to step S 176 . 
     In step S 176 , the cartilage conduction vibration unit  1626  is turned on in order for audio information to be listened to, and in step S 182  the outgoing-talk unit (microphone)  1423  is turned on in order for speaking to be performed; the flow then moves on to step S 184 . In step S 184 , there is performed a check for whether it has been detected that the movable unit  1591  is bent at or above a predetermined angle. When bending has been detected, the flow then proceeds to step S 186 , in which the waveform inversion signal of one&#39;s own voice is added to the cartilage conduction vibration unit  1626 ; the flow then moves on to step S 188 . On the other hand, when there is no detection in step S 184  that the bending is at or above the predetermined angle, the flow moves on to step S 190 , and then on to step S 188  without the waveform inversion signal of one&#39;s own voice being added to the cartilage conduction vibration unit  1626 . In step S 188 , there is performed a check for whether or not a signal to the effect that the call state has been cut off has been received from the mobile telephone  1601 ; when the call has not been cut off, the flow returns to step S 176 , following which steps S 176  to S 188  are repeated until a call interruption is detected in step S 188 . Support is thereby provided for the generation and elimination of the earplug bone conduction effect that is based on the bending of the movable unit  1591  during a call. 
     On the other hand, when it is detected in step S 188  that a call interruption signal has been received from the mobile telephone  1601 , the flow proceeds to step S 192 , in which listening using the cartilage conduction vibration unit  1626  is turned off and speaking using the outgoing-talk unit (microphone)  1423  is turned off; the flow then moves on to step S 194 . In step S 194 , there is performed a check for whether a no-call state has continued for a predetermined period of time or longer; when this is true, the flow moves on to step S 196 . In step S 196 , there is a shift to a power-saving standby state, such as one in which the clock frequency is lowered to the minimum level required to maintain the standby state of the short-range communication unit  1487 ; processing is also done to permit an interruption for reinstating the short-range communication unit  1487  to an ordinary call state, in response to the receipt of an incoming call signal from the mobile telephone  1601  or an outgoing call operation of the operation unit  1409 . Then, after such processing, the flow moves on to step S 198 . On the other hand, when there is no detection in step S 194  of a no-call state lasting a predetermined period of time or longer, the flow moves directly on to step S 198 . However, the flow also moves directly on to step S 198  when it is not possible in step S 166  to confirm that short-range communication has been established, or when there is no detection in step S 178  of an outgoing call operation, or when it is not possible in step S 180  to confirm that a telephone connection has been established. 
     In step S 198 , there is performed a check for whether the primary power supply has been turned off by the operation unit  1409 , the flow being terminated in a case in which it is detected that the primary power supply has been turned off. On the other hand, in a case in which it is not detected that the primary power supply has been turned off, the flow returns to step S 166 , following which steps S 166  to S 198  are repeated until primary power supply is turned off, to support various changes to the state of the headset  1681 . 
     The flow in  FIG. 30  can be applied not only to the configuration of the system diagram in  FIG. 27 , but also to the system diagram of the fifteenth embodiment in  FIG. 26 . The same can also be applied to the thirteenth embodiment in  FIG. 24  or to the fourteenth embodiment in  FIG. 25  when the “bending detection” in step S 184  is read as a detection of the presence or absence of the state in which the “earplug bone conduction effect” is generated, as in step S 52  of  FIG. 10 . 
     Eighteenth Embodiment 
       FIG. 31  is a flow chart of the controller of a headset in which, instead of having the bending be detected by a mechanical switch in the seventeenth embodiment of  FIG. 30 , the configuration is such that same is achieved using software; the description is provided as an eighteenth embodiment, in order to avoid confusion with  FIG. 30 . Steps that  FIG. 31  has in common with  FIG. 30  have been given like step reference numerals, a description thereof having been omitted unless there is a particular need.  FIG. 31  uses boldface print and bold frames to illustrate points of difference, and thus the following description focuses on these portions. More specifically, the eighteenth embodiment is configured such that, with the assumption that the cartilage conduction vibration unit  1626  is a piezoelectric bimorph element and conforming to the fourth embodiment in  FIG. 9 , a signal appearing on a signal wire for connecting the phase adjustment mixer unit  1636  and the cartilage conduction vibration unit  1626  is monitored, and changes in the signal appearing for the cartilage conduction vibration unit (which is a piezoelectric bimorph element)  1626  are monitored by the strain that is based on the operational impact from the bending of the movable unit  1591  or at the moment of recovery from the bending thereof. The signal change is then processed by software, whereby the bending state is detected. 
     On the basis of the assumption above, there shall now be provided a description of how  FIG. 31  is different from  FIG. 30 . First, step S 200  is depicted by the consolidation of steps S 170  to S 174 , step S 178 , and step S 180  in  FIG. 30 , the content thereof being identical. Then, when a telephone connection is established on the basis of an operation to receive an incoming call or of the response of the other party to an outgoing call, the flow moves on to step S 176 ; when there is no telephone connection, the flow moves on to step S 198 . 
     Steps S 202  to S 210  are steps that relate to detecting bending; once steps S 182  to S 202  are reached, first, a signal appearing on the input terminal of the cartilage conduction vibration unit  1626  (the signal wire connecting the phase adjustment mixer unit  1636  and the cartilage conduction vibration unit  1626 ) is sampled. In step S 204 , drive output of the cartilage conduction unit going from the controller  1639  to the phase adjustment mixer unit  1636  at the same timing is sampled at the same timing. Subsequently, in step S 206 , the difference between these sampling values is calculated, and in step S 208 , there is a detection for whether the calculated difference is at or above a predetermined value. This function corresponds to the function of the pressure sensor  242  in  FIG. 9 , but whereas the pressure state is continuously detected by the pressure sensor  242  of  FIG. 9 , the system in  FIG. 27  uses operational impact from bending or at the moment of recovery from bending to perceive changes to the bending state. 
     When it is detected in step S 208  that the two sampling values have generated a difference at or above the predetermined value, the flow moves on to step S 210 . It is not known at the stage in step S 208  whether the difference in the two sampling values at or above the predetermined value has been generated due to bending or has been generated due to recovery from bending. However, after the cartilage conduction vibration unit  1626  has been turned on in step S 176 , there is a check in step S 210  for whether the number of times a difference has been generated is an odd number, on the basis of the difference generation history. When the number of times is an odd number, the flow moves on to step S 186 , and when the number of times is an even number, the flow moves on step S 190 . Because the movable unit  1591  necessarily alternates between bending and recovering from bending, there can be an alternation between whether or not the phase-inverted signal of one&#39;s own voice is added each time there is an operational impact in the manner described above. However, the difference generation history can be reset using the operation unit  1409  in the event that the difference count is ever inverted by a mistaken operation. 
     Step S 212  is depicted by the consolidation of step S 194  and step S 196  in  FIG. 30 , the content thereof being identical. As described above, similarly with respect to the fourth embodiment and the like, the sensor function of the cartilage conduction vibration unit  1626  itself is utilized in the eighteenth embodiment to detect the bending of the movable unit  1591 , whereby the state in which the earplug bone conduction effect occurs is determined to be in effect. The flow of  FIG. 31  can be applied not only to the configuration of the system diagram in  FIG. 27 , but also to the system diagram of the fifteenth embodiment in  FIG. 26 . Also, in a case such as in the fifth to tenth embodiments, in which the cartilage conduction vibration unit is held by an elastic body, the scheme in  FIG. 31  for detecting the occurrence of the earplug bone conduction effect can also be utilized in a case in which there is no continuous strain on the cartilage conduction vibration unit in the state in which the earplug bone conduction effect occurs. 
     Nineteenth Embodiment 
       FIG. 32  is a structural diagram illustrating the system of the nineteenth embodiment according to an aspect of the present invention. The nineteenth embodiment is also configured as an incoming/outgoing-talk unit for a mobile telephone, and together with the mobile telephone  1401  creates a mobile telephone system. In the nineteenth embodiment, as illustrated in  FIG. 32 , the incoming/outgoing-talk unit is configured as eyeglasses  1781 . Because the nineteenth embodiment assumes a system configuration in common with that of the fifteenth embodiment, common parts have been given like reference numerals; in a case in which there is no particular description, that configuration is shared with that of the fifteenth embodiment. Also, in the nineteenth embodiment as well, the mobile telephone  1401  may in some cases have a special configuration to be used in combination with the eyeglasses  1781  creating an incoming/outgoing-talk unit, and may in other cases be configured as a typical mobile telephone having a short-range communication function. In the latter case, the eyeglasses  1781  take on a configuration as an accessory of the mobile telephone  1401 , similarly with respect to the fifteenth embodiment. 
     In the nineteenth embodiment, as illustrated in  FIG. 32 , a movable unit  1791  is rotatably attached to the temple piece of the eyeglasses  1781 ; in the state depicted, a cartilage conduction vibration unit  1726  is in contact with the tragus  32  of the right ear  28 . The movable unit  1791  can be rotationally withdrawn to a position along the temple of the eyeglasses  1781  as indicated by the single-dotted line  1792  in a case in which same is not to be used. The cartilage conduction vibration unit  1726  can be made to vibrate at low frequency in this withdrawn state as well; it can thereby be known that there is an incoming call when the vibration of the temple of the eyeglasses  1781  is felt on the face. The outgoing-talk unit (microphone)  1723  is arranged at the front portion of the temple of the eyeglasses  1781 . The controller  1739 , which comprises a power supply unit, is arranged at the portion of the temple on the eyeglasses  1781 , and controls the cartilage conduction vibration unit  1726  and the outgoing-talk unit (microphone)  1723 . A Bluetooth™ or other type of short-range communication unit  1787 , which is capable of wireless communication with the mobile telephone  1401  by radio waves  1285 , is further arranged at the portion of the temple on the eyeglasses  1781 , sending audio from the user, which is picked up by the outgoing-talk unit (microphone)  1723 , to the mobile telephone  1401 , and also making it possible to cause the cartilage conduction vibration unit  1726  to vibrate on the basis of the audio information that is received from the mobile telephone  1401 . The rear end part of the temple of the eyeglasses  1781  is provided with an incoming/outgoing-talk operation unit  1709 . Since the temple of the eyeglasses  1781  is a portion that comes against a bone at the rear of the ear  28  (the mastoid part), it is supported in a backed state, and incoming/outgoing-talk operations, such as pressing on the temple from the front side, can be easily performed without causing the eyeglasses  1781  to deform. The arrangement of each of the aforementioned elements is not to be limited to the description above; all or a part of the elements may be integrated in the movable unit  1791  as appropriate. 
     The movable unit  1791 , having an elastic body  1773  interposed partway therealong, is pushed from the outside and caused to bend when listening comprehension of audio information is impaired by environment noise; the cartilage conduction vibration unit  1726  is then pushed on the tragus  32  with greater pressure, whereby the tragus  32  more readily obstructs the hole of the ear. The ear plug conduction effect, which has also been described in the other embodiments, can thereby be generated, and even louder audio information can thereby be transmitted. Information on one&#39;s own voice, which is picked up from the outgoing-talk unit (microphone)  1723 , is also subjected to phase inversion on the basis of the mechanical detection of the bent state of the movable unit  1791 . The information is then transmitted to the cartilage conduction vibration unit  1726 , and one&#39;s own voice is canceled out. These are points in common with the fifteenth embodiment. 
     The block diagrams of  FIGS. 28 and 29  can be applied to the nineteenth embodiment by reading “headset” as “eyeglasses.” The flow charts of  FIGS. 30 and 31  can also be applied to the nineteenth embodiment. 
     Twentieth Embodiment 
       FIG. 33  is a diagram of the system of the twentieth embodiment according to an aspect of the present invention. The twentieth embodiment is also configured as an incoming/outgoing-talk unit for a mobile telephone, and together with the mobile telephone  1401  creates a mobile telephone system. The twentieth embodiment takes the configuration of a system in common with that of the nineteenth embodiment in  FIG. 32 ; therefore, portions that are in common have been given like reference numerals, a description thereof being omitted unless there is a particular need. Also similarly with respect to the nineteenth embodiment, the mobile telephone  1401  in the twentieth embodiment as well may in some cases have a special configuration to be used in combination with a pair of eyeglasses  1881  creating an incoming/outgoing-talk unit, and may in other cases be configured as a typical mobile telephone having a short-range communication function. In the latter case, the eyeglasses  1881  take on a configuration as an accessory of the mobile telephone  1401 , similarly with respect to the nineteenth embodiment. 
     A point of difference in the twentieth embodiment from the nineteenth embodiment lies in that the cartilage conduction vibration unit  1826  is provided within an ear-hook unit  1893 , by which the temple of the eyeglasses  1881  comes up against the base of the ear  28 . As a result thereof, the vibration of the cartilage conduction vibration unit  1826  is transmitted to the outer side  1828  of the cartilage of the base of the ear  28 ; air conduction sound is generated from the inner wall of the external auditory meatus for transmission to the tympanic membrane via the cartilage around the entrance to the external auditory meatus, and a part is also transmitted directly to the inner ear through the cartilage. The outer side  1828  of the cartilage of the base of the ear  28 , against which the temple of the eyeglasses  1881  comes, being close to the inner entrance of the external auditory meatus, is suitable for generating air conduction to the interior of the external auditory meatus from the cartilage around the entrance to the external auditory meatus and for direct conduction to the inner ear through the cartilage. 
     The ear-hook unit  1893  is further provided with an ear pushing detection unit  1888  at the portion coming up against the rear side of the ear lobe. The ear pushing detection unit  188  mechanically detects the state in which the ear lobe is pushed due to the palm of the hand coming against the ear  28  when there is loud external noise, in order to block same; the controller  1739  transmits this ear pushing detection information to the mobile telephone  1401  from the short-range communication unit  1787 . The ear pushing detection unit  1888  can be made of, for example, a switch that is mechanically turned on when pushed by the rear side of the ear lobe. The controller  239  of the mobile telephone  1401  (in the case in which the configuration calls on that of  FIG. 28 ) controls the phase adjustment mixer unit  236  on the basis of the bending detection information received by the short-range communication unit  1446 , and determines whether or not to add, to the audio information from the incoming-talk-processing unit  212 , the signal of the waveform inverter  240  that is based on one&#39;s own voice transmitted from the microphone  1723  to the outgoing-talk-processing unit  222  via the short-range communication unit  1446 . A configuration relating to a countermeasure for when the earplug bone conduction effect is generated, similarly with respect to the nineteenth embodiment, can also be configured by calling on  FIG. 29 . 
     Twenty-First Embodiment 
       FIG. 34  is a side view of the elements of the twenty-first embodiment according to an aspect of the present invention. The twenty-first embodiment is also configured as an incoming/outgoing-talk unit for a mobile telephone, and together with the mobile telephone  1401  (not shown) creates a mobile telephone system, similarly with respect to the twentieth embodiment. The twenty-first embodiment takes the configuration of a system analogous to that of the twentieth embodiment in  FIG. 33 ; therefore, portions that are in common have been given like reference numerals, a description thereof being omitted unless there is a particular need. More specifically, a point of difference is that, whereas the incoming/outgoing-talk unit of the twentieth embodiment is configured as specialized eyeglasses, the incoming/outgoing-talk unit of  FIG. 34  is configured as an eyeglasses attachment  1981  that can be attached to an ear-hook unit  1900  of the temple of ordinary eyeglasses. The configuration is otherwise consistent with that of the twentieth embodiment in  FIG. 33 . Also similarly with respect to the twentieth embodiment, the mobile telephone  1401  (not shown) in the twenty-first embodiment may in some cases have a special configuration to be used in combination with the eyeglasses attachment  1981  creating an incoming/outgoing-talk unit, and may in other cases be configured as a typical mobile telephone having a short-range communication function. In the latter case, the eyeglasses attachment  1981  takes on a configuration as an accessory of the mobile telephone  1401 , similarly with respect to the twentieth embodiment. 
     The eyeglasses attachment  1981  is molded as a one-size-fits-all elastic body cover capable of covering the variously sized and/or shaped ear-hook unit  1900 ; when the ear-hook unit  1900  is inserted from the opening of one end thereof, the cartilage conduction vibration unit  1926  comes into contact with the top side of the ear-hook unit  1900 . This contact may be achieved directly or via the coating of the elastic body of the eyeglasses attachment  1981 . For this purpose, the elastic body is preferably selected to be of a material having an acoustic impedance that approximates that of ear cartilage. The aforementioned direct or indirect contact transmits the vibration of the cartilage conduction vibration unit  1926  to the ear-hook unit  1900 , the vibration thereof then being transmitted to the outer side of the base of the ear  28 ; therefore, similarly with respect to the twentieth embodiment, air conduction sound is generated from the inner wall of the external auditory meatus for transmission to the tympanic membrane via the cartilage around the entrance to the external auditory meatus, and a part is also transmitted directly to the inner ear through the cartilage. 
     Each of the outgoing-talk unit (microphone)  1723 , the controller  1739 , the short-range communication unit  1787 , the incoming/outgoing-talk operation unit  1709 , and the ear pushing detection unit  1888  provided to the eyeglasses  1881  in the twentieth embodiment is arranged within the eyeglasses attachment  1981  in the twenty-first embodiment in  FIG. 34 ; however, the functions thereof are shared and therefore a description has been omitted. Although not depicted, in a case in which, for example, the ear-hook unit  1900  on the right is covered with the eyeglasses attachment  1981 , a dummy cover molded from an elastic body having the same outer shape, material, and weight is provided as an ear-hook unit on the left. Covering the eyeglasses attachment  1981  makes it possible to keep the left-right balance when the eyeglasses are worn. Since the eyeglasses attachment  1981  and the dummy cover are molded using the same elastic body, they can accordingly be configured such that each can be worn as desired as either the left or right ear-hook unit by being slightly deformed. For example, as the inverse of the description above, the left ear-hook unit can be covered with the eyeglasses attachment  1981  and the right ear-hook unit can be covered with the dummy cover. There is accordingly no need to market an assortment of eyeglasses attachments  1981  for either right ear use or left ear use. 
     Twenty-Second Embodiment 
       FIG. 35  is a top view of the twenty-second embodiment according to an aspect of the present invention. The twenty-second embodiment is also configured as an incoming/outgoing-talk unit for a mobile telephone, and together with the mobile telephone  1401  (not shown) creates a mobile telephone system, similarly with respect to the twenty-first embodiment. The twenty-second embodiment takes the configuration of a system analogous to that of the twenty-first embodiment in  FIG. 34 ; therefore, portions that are in common have been given like reference numerals, a description thereof being omitted unless there is a particular need. The incoming/outgoing-talk unit of the twenty-second embodiment, similarly with respect to the twenty-first embodiment, is also configured as an eyeglasses attachment  2081  that is molded as a one-size-fits-all elastic body cover capable of covering the variously sized and/or shaped ear-hook unit  1900  in ordinary eyeglasses. 
     A point of difference in the twenty-second embodiment in  FIG. 35  from the twenty-first embodiment in  FIG. 34  lies in that each of the constituent elements of the incoming/outgoing-talk unit, which in the twenty-first embodiment are arranged concentratedly in the eyeglasses attachment  1981 , one side of which is covered with the ear-hook unit  1900 , are distributed in the left and right ear-hook unit  1900 . More specifically, the eyeglasses attachment  2081  of the twenty-second embodiment is made of a right-side elastic body cover  2082 , a left-side elastic body cover  2084 , and a dual-purpose glass-cord cable  2039  for connecting same to be able to communicate via a wire; each of the constituent elements of the incoming/outgoing-talk unit being arranged in a distributed fashion therein. For convenience of description, the elastic body cover  2082  is intended for use on the right ear and the elastic body cover  2084  is intended for use on the left ear, but each of the ear-hook units  1900  can be covered with this pair of elastic body covers in a left-right inversion. 
     In the aforementioned basic configuration, the cartilage conduction vibration unit  1926 , the incoming/outgoing-talk operation unit  1709 , and the ear pushing detection unit  1888  are arranged on the right-side elastic body cover  2082 . Similarly with respect to the twenty-first embodiment, the vibration of the cartilage conduction vibration unit  1926  is thereby transmitted to the cartilage around the opening of the external auditory meatus via the ear-hook unit  1900 . Air conduction sound is generated from the wall inside the external auditory meatus and transmitted to the tympanic membrane, and a part is transmitted directly to the inner ear through the cartilage. 
     On the other hand, the outgoing-talk unit (microphone)  1723 , the controller  1739 , and the short-range communication unit  1787  are arranged on the left-side elastic body cover  2084 . The dual-use glass-cord cable  2039  has a glass cord design so that the eyeglasses can be hung on the neck when removed, and functions through wiring that connects each of the constituent elements of the incoming/outgoing-talk unit, which are arranged in a distributed fashion in the right-side elastic body cover  2082  and the left-side elastic body cover  2084 . Connecting the right-side elastic body cover  2082  and the left-side elastic body cover  2084  using the dual-use glass-cord cable  2039  prevents one side from being misplaced when removed from the eyeglasses. 
     Twenty-Third Embodiment 
       FIG. 36  is a block diagram of the twenty-third embodiment according to an aspect of the present invention. The twenty-third embodiment, similarly with respect to either the nineteenth embodiment or the twentieth embodiment, includes eyeglasses  2181  configured as an incoming/outgoing-talk unit for a mobile telephone, and together with the mobile telephone  1401  (not shown) creates a mobile telephone system. Similarly with respect to the twenty-second embodiment, each element constituting the incoming/outgoing-talk unit in the twenty-third embodiment is arranged in a distributed fashion to a right temple unit  2182  and a left temple unit  2184 . The individual constituent elements and the functions thereof can be understood in accordance with the block diagram of the seventeenth embodiment in  FIG. 29  and that of the top view of the twenty-second embodiment in  FIG. 35 ; therefore, portions that are in common have been given like reference numerals, a description thereof being omitted unless there is a particular need. In the twenty-third embodiment as well, the vibration of the cartilage conduction vibration unit  1826  arranged at the right temple unit  2182  is transmitted to the outer side of the cartilage of the base of the ear  28 ; this causes the cartilage around the entrance to the external auditory meatus to vibrate, whereby air conduction sound generated from the wall inside the external auditory meatus is transmitted to the tympanic membrane, and a part of the cartilage vibration is directly transmitted to the inner ear through the cartilage. 
     The twenty-third embodiment in  FIG. 36  further has a configuration for visualizing a three-dimensional (“3D”) image received from the mobile telephone  1401  in a lens unit  2186 . The lens unit  2186  of the eyeglasses  2181  is provided with a right lens  2110  and a left lens  2114  originally intended for eyeglasses, and functions as ordinary eyeglasses. Furthermore, when the short-range communication unit  1787  receives 3D image information from the mobile telephone  1401 , the controller  1639  instructs a 3D display drive unit  2115  to display same. The 3D display drive unit  2115 , on the basis thereof, causes a right eye image and left eye image to be displayed on a right display unit  2118  and a left display unit  2122 , respectively. These images are imaged on the retinas of the right eye and the left eye by a right eye light-guiding optical system  2129  and a left eye light-guiding optical system  2141 , which comprise an imaging lens, a half mirror, and other components; and it will be possible to appreciate the 3D image in an aesthetic sense. This 3D image is viewed in a form that is synthesized with or superimposed on a raw image that enters the retinas from the right lens  2110  and the left lens  2114 . 
     Twenty-Fourth Embodiment 
       FIG. 37  is a diagram of the system of the twenty-fourth embodiment according to an aspect of the present invention. The twenty-fourth embodiment is also configured as an incoming/outgoing-talk unit for a mobile telephone, and together with the mobile telephone  1401  creates a mobile telephone system. The incoming/outgoing-talk unit of the twenty-fourth embodiment, although being configured as an ear-hook unit  2281  used for hearing aids or the like, otherwise takes the configuration of a system in common with that of the twentieth embodiment in  FIG. 33 ; therefore, portions that are in common have been given like reference numerals, a description thereof being omitted unless there is a particular need. Also similarly with respect to the twentieth embodiment, the mobile telephone  1401  in the twenty-fourth embodiment may in some cases have a special configuration to be used in combination with the ear-hook unit  2281  creating an incoming/outgoing-talk unit, and may in other cases be configured as a typical mobile telephone having a short-range communication function. In the latter case, the ear-hook unit  2281  takes on a configuration as an accessory of the mobile telephone  1401 , similarly with respect to the twentieth embodiment. 
     In the twenty-fourth embodiment, the cartilage conduction vibration unit  2226  is arranged at a position coming up against the rear part of the outer side  1828  of the cartilage of the base of the ear  28 . As a result thereof, similarly with respect to the twentieth embodiment, the vibration of the cartilage conduction vibration unit  2226  is transmitted to the outer side  1828  of the cartilage of the base of the ear  28 ; air conduction sound is generated from the inner wall of the external auditory meatus for transmission to the tympanic membrane via the cartilage around the entrance to the external auditory meatus, and a part is also transmitted directly to the inner ear through the cartilage. The outer side  1828  of the cartilage of the base of the ear  28 , being close to the inner entrance of the external auditory meatus thereof, is suitable for generating air conduction to the interior of the external auditory meatus from the cartilage around the entrance to the external auditory meatus and for direct conduction to the inner ear through the cartilage. However, in the case in which the incoming/outgoing-talk unit is configured as an ear-hook unit  2281 , as in the twenty-fourth embodiment, there is a great degree of freedom in the arrangement of the cartilage conduction vibration unit  2226  for making contact with the outer side  1828  of the cartilage of the base of the ear  28 ; therefore, the cartilage conduction vibration unit  2226  can be arranged at an optimum position, taking into consideration the mounting layout and vibration conduction effect for the structure of the incoming/outgoing-talk unit. Accordingly, similarly with respect to the twentieth embodiment, in the twenty-fourth embodiment there may also be employed an arrangement by which the cartilage conduction vibration unit  2226  comes up against the upper part of the outer side  1828  of the cartilage of the base of the ear  28 . 
     The ear-hook unit  2281 , similarly with respect to the case of the eyeglasses  1881  in the twentieth embodiment, is provided with an outgoing-talk unit (microphone)  1723 , a controller  1739 , a short-range communication unit  1787 , an incoming/outgoing-talk operation unit  1709 , and an ear pushing detection unit  1888 , the associated functions being consistent therewith and an attendant description accordingly being omitted. In the case of the ear-hook unit  2281  of the twenty-fourth embodiment, the outgoing-talk unit (microphone)  1723  is arranged frontwardly with respect to the ear. 
     Twenty-Fifth Embodiment 
       FIG. 38  is block diagram of the twenty-fifth embodiment according to an aspect of the present invention. The twenty-fifth embodiment is consistent with the twentieth to twenty-third embodiments in that the cartilage conduction vibration units  2324  and  2326  are arranged at the ear-fitting parts of the temples of an eyeglasses-type device and in that the vibration is transmitted to the outer side of the cartilage of the base of the ear  28 ; however, this embodiment is configured not as an incoming/outgoing-talk unit of a mobile telephone but rather as 3D television viewing eyeglasses  2381 , and together with a 3D television  2301  creates a 3D television viewing system. The twenty-fifth embodiment makes it possible to experience stereo audio information; the vibration of a right-ear cartilage-conduction vibration unit  2324  arranged at the right temple unit  2382  is transmitted to the outer side of the cartilage of the base of the right ear via a contact unit  2363 , and causes the cartilage around the entrance to the external auditory meatus to vibrate, air conduction sound that is thereby generated from the wall inside the external auditory meatus being transmitted to the right tympanic drum, and a part of the cartilage conduction being transmitted directly to the inner ear through the cartilage. Similarly, the vibration of a left-ear cartilage-conduction vibration unit  2326  arranged at the left temple unit  2384  is transmitted to the outer side of the cartilage of the base of the left ear via a contact unit  2364 , and causes the cartilage around the entrance to the external auditory meatus to vibrate, whereby air conduction sound that is generated from the wall inside the external auditory meatus is transmitted to the left tympanic drum, and a part of the cartilage conduction is transmitted directly to the inner ear through the cartilage. 
     The viewing eyeglasses  2381  are configured to be wearable over ordinary eyeglasses by any person wearing the same; in this case, the vibrations of the right-ear cartilage-conduction vibration unit  2324  and the left-ear cartilage-conduction vibration unit  2326  are respectively transmitted to the cartilage of the base of the left and right ears, which are in direct contact therewith via the contact units  2363  and  2364 , and are also respectively transmitted to the ear-hook units of the left and right temples of the ordinary eyeglasses and indirectly transmitted to the cartilage of the base of the ear via the ear-hook units. The contact units  2363  and  2364  are configured in a shape such that cartilage conduction appropriate for the cartilage of the base of the ear is generated, both in a case in which a person without eyeglasses wears the viewing eyeglasses  2381  and in a case in which they are worn over ordinary eyeglasses. A description thereof will be provided further below. 
     The 3D television  2301  generates an audio signal from a stereo audio signal unit  2331  on the basis of the control of the controller  2339 ; an infrared communication unit  2346  transmits this audio signal to an infrared communication unit  2387  of the viewing eyeglasses  2381  using infrared rays  2385 . The controller  2339  of the viewing eyeglasses  2381  outputs a left and a right audio signal from a right audio drive unit  2335  and a left audio drive unit  2336  on the basis of the received audio signal, and causes the right-ear cartilage-conduction vibration unit  2324  and the left-ear cartilage-conduction vibration unit  2326  to vibrate. The aforementioned infrared communication unit  2387 , the controller  2339 , the right audio drive unit  2335 , the left audio drive unit  2336 , as well as a shutter drive unit  2357 , a right shutter  2358  and a left shutter  2359  (to be described later), together with a power supply unit  2348 , are arranged on an eyeglasses primary unit  2386 . 
     On the other hand, the 3D television  2301  sends a video signal of a video signal unit  2333  to a display driver  2341  on the basis of the control of the controller  2339 , and displays a 3D image on a 3D screen  2305  comprising a liquid crystal display unit or the like. The controller  2339  further synchronizes with the 3D image display to generate a synchronization signal from a 3D shutter synchronization signal unit  2350 , and the infrared communication unit  2346  transmits this synchronization signal to the infrared communication unit  2387  of the viewing eyeglasses  2381  using the infrared rays  2385 . The controller  2339  of the viewing eyeglasses  2381  controls the shutter drive unit  2357  on the basis of the received synchronization signal, and opens the right shutter  2358  and the left shutter  2359  in alternation. A right eye image  2360  and a left eye image  2362 , which are displayed in alternation on the 3D screen  2305 , are thereby made to be incident on the right eye and the left eye in synchronization. In the twenty-fifth embodiment, the stereo audio signal for driving the cartilage conduction vibration unit and the 3D shutter synchronization signal are thus transmitted by the infrared communication between the infrared communication units  2346  and  2387 . These two signals are sent in parallel by either time division or by synthesis. The communication therebetween is not to be limited to communication by infrared rays, but rather may be achieved using short-range wireless communication, as in other embodiments. 
       FIG. 39  is a cross-sectional view of the elements of the aforementioned twenty-fifth embodiment; the cross-section of the right temple unit  2382  is illustrated in a state in which the viewing eyeglasses  2381  have been worn since the ordinary eyeglasses were put on.  FIG. 39A  is a cross-section of the right temple unit  2382  relating to the twenty-fifth embodiment, and  FIG. 39B  illustrates a cross-section of a modification example thereof. First, a description of  FIG. 39A  shall be provided. A contact unit  2363  is provided to the portion of the bottom of the right temple unit  2382  that is worn on the ear  28 . This contact unit  2363  comprises an elastic body having an acoustic impedance approximating that of ear cartilage, and the right-ear cartilage-conduction vibration unit  2324  is held in the right temple unit  2382  configured so as to be enveloped therein. The cross-section of the contact unit  2363 , as is clear from  FIG. 39A , is provided with a groove into which the ear-hook unit  2300  of the ordinary eyeglasses is to be fitted. The right temple unit  2382  of the viewing eyeglasses  2381  achieves reliable contact with the ear-hook unit  2300  of the temple of the ordinary eyeglasses, and the elasticity of the contact unit  2363  prevents the contacted portions of the right temple unit  2382  and the ear-hook unit  2300  from buzzing due to vibration. In the state of  FIG. 39A , the vibration of the right-ear cartilage-conduction vibration unit  2324  is transmitted to the outer side  1828  of the cartilage of the base of the right ear  28 , in direct contact therewith via the contact unit  2363 , and is also transmitted to the ear-hook unit  2300  of the right temple of the ordinary eyeglasses, and indirectly transmitted to the outer side  1828  of the cartilage of the base of the ear  28  via this ear-hook unit  2300 . 
     On the other hand, in a case in which a person without eyeglasses wears the viewing eyeglasses  2381  directly, the entire contact unit  2363  is in direct contact with the outer side  1828  of the cartilage of the base of the right ear  28 , and transmits the vibration of the right-ear cartilage-conduction vibration unit  2324  thereto. The outer side of the contact unit  2363  is beveled, and therefore the right temple unit  2382  will fit to the ear  28  without discomfort even in this case. 
     Next, in a modification example in  FIG. 39B , as is clear from the cross-sectional view thereof, a contact unit  2363  is provided to the portion of the bottom of the right temple unit  2382  that is worn on the ear  28 , similarly with respect to  FIG. 39A . Also similarly with respect to  FIG. 39A , the contact unit  2363  comprises an elastic body having an acoustic impedance approximating that of ear cartilage, and the right-ear cartilage-conduction vibration unit  2324  is held at the right temple unit  2382  configured so as to be enveloped therein. As is clear from  FIG. 39B , the cross-sectional shape of the contact unit  2363  is different in the modification example, a concave slope being provided instead of the groove; the right temple unit  2382  of the viewing eyeglasses  2381  thereby achieves reliable contact with the outer side of the ear-fitting part  2300  of the temple of the ordinary eyeglasses so as to be hooked on the ear  28 , and the elasticity of the contact unit  2363  prevents the contact portions of the right temple unit  2382  and the ear-hook unit  2300  from buzzing due to vibration. In the state of  FIG. 39B , the vibration of the right-ear cartilage-conduction vibration unit  2324  is transmitted to the outer side  1828  of the cartilage of the base of the right ear  28 , in direct contact therewith via the contact unit  2363 , and is also transmitted to the ear-hook unit  2300  of the right temple of the ordinary eyeglasses, and indirectly transmitted to the outer side  1828  of the cartilage of the base of the ear  28  via this ear-hook unit  2300 . 
     On the other hand, in a case in which a person without eyeglasses wears the viewing eyeglasses  2381 , the entire contact unit  2363  is in direct contact with the outer side  1828  of the cartilage of the base of the right ear  28 , and transmits the vibration of the right ear conduction vibration unit  2324  thereto. The outer side of the contact unit  2363  is also beveled in the case of the modification example in  FIG. 39B ; the right temple unit  2382  is fitted to the ear  28  without discomfort even in a case in which the viewing eyeglasses  2381  are worn directly. As is clear from  FIG. 39B , it is the contact with the ear cartilage of the bottom or the outer side of the temple of the eyeglasses that is essential in cartilage conduction, and not with the facial cartilage at the inner side of the temple of the eyeglasses; the shape of the contact unit is determined to meet this purpose. 
     As described above, in the twentieth to twenty-fifth embodiments, the vibration of the cartilage conduction vibration unit  2324  is transmitted to the outer side of the cartilage of the base of the ear. This causes the cartilage around the entrance to the external auditory meatus to vibrate, whereby air conduction sound that is generated from the wall inside the external auditory meatus is transmitted to the tympanic membrane, and a part of the cartilage conduction is directly transmitted to the right inner ear through the cartilage. Favorable conduction by contact with the outer side of the ear cartilage can accordingly be achieved merely by wearing the eyeglasses in an ordinary state. By contrast, in a case using conventional bone conduction, the bone at the front or the rear of the ear must be tightly tucked in by the portion of the inner side of the temple of the eyeglasses, which results in pain and renders long-term usage unbearable. The present invention does not have such a problem, it being possible to listen comfortably to audio information while experiencing a sensation similar to that of ordinary eyeglasses. 
     The various features of each of the embodiments described above are not to be restricted to individual embodiments, but rather can be substituted or combined with other appropriate embodiments. For example, in the description of the twenty-first embodiment in  FIG. 34 , the ear-hook unit of the other temple is covered with a dummy cover, but the configuration of  FIG. 34  can be prepared as a pair; when the ear-hook units of the left and right temples are made to be each covered, it becomes possible to listen to stereo audio signals as in the twenty-fifth embodiment of  FIG. 38 . The two ear-hook units can also be connected by wireless connection at this time, but a connection by the dual-use glass-cord cable as in the twenty-second embodiment of  FIG. 35  is also possible. Regarding the feature of the glass cord, a link between the configuration of  FIG. 34  and the dummy cover in the twenty-first embodiment may be made with a glass cord, thus preventing misplacement. Regarding the aforementioned feature of achieving a stereo effect, when the twenty-third embodiment of  FIG. 36  is also configured such that the constituent elements are not divided into left and right similarly with respect to the description above, but rather two sets of the required constituent elements are prepared and each is positioned at the left and right temple units, it becomes possible not only to make an image into 3D but also to listen to stereo audio signals, as in the twenty-fifth embodiment of  FIG. 38 . Referring to the twenty-fifth embodiment, a part the left-right configuration at this time can be shared as appropriate (for example, at least the controller and the power supply). 
     In the aforementioned embodiments, the effects of the present invention have been described by way of example using a mobile telephone and an incoming/outgoing-talk unit thereof or 3D video viewing eyeglasses. However, the advantages of the present invention are not to be limited thereto; the invention can be implemented in other applications. For example, the various features of the present invention described above would also be effective when implemented in a hearing aid. 
     The various features of each of the embodiments described above are not to be limited to the individual embodiments; rather, wherever it is possible to benefit from the feature of an embodiment, same may be variously implemented in an embodiment in which the feature has been modified. For example,  FIG. 40  is a perspective view illustrating a modification example of the tenth embodiment in  FIG. 19 . In this modification example as well, similarly with respect to  FIG. 19 , the cartilage conduction vibration source  925 , which comprises a piezoelectric bimorph element or the like, serves as the cartilage conduction vibration source, while also taking the role of a drive source of the incoming-talk unit for generating sound waves that are transmitted to the tympanic membrane by air conduction. However, the cartilage conduction vibration source  925  stretches to the side of the mobile telephone  901  in the modification example of  FIG. 40 , the right end  224  and left end  226  thereof being made to vibrate. Sound can accordingly be heard by cartilage conduction due to either one thereof being caused to contact the tragus, similarly with respect to the nineteenth embodiment. The cartilage conduction vibration source  925  vibrates as a whole, rather than vibrating at only the right end  224  and left end  226  thereof. Audio information can accordingly be transmitted regardless of where on the top inner edge of the mobile telephone  901  contact with the ear cartilage is made, similarly with respect to  FIG. 19 . Also, a point of similarity with  FIG. 19  lies in that the cartilage conduction output unit  963 , which is made of a material having an acoustic impedance approximating that of ear cartilage, is arranged frontwardly with respect to the cartilage conduction vibration source  925 . 
     The following is a possible modification example for the twenty-third embodiment of  FIG. 36 . Namely, the outgoing-talk unit (microphone)  1723  in the twenty-third embodiment is an ordinary air conduction microphone, but when the outgoing-talk unit (microphone)  1723  is instead a bone conduction microphone (a microphone or pickup of the bone conduction contact type), it becomes possible to selectively pick up the audio of the speaking party without picking up any undesired sound when in the presence of noise. It further becomes possible to speak in an undertone that will not disturb the surroundings. It is natural that the temples of eyeglasses are generally in contact with the bone at the front of the ear (the zygomatic arch, or a part of the temporal bone on the zygomatic arch) or the bone at the rear of the ear (the mastoid process of the temporal bone). Accordingly, calling on  FIG. 36 , arranging the outgoing-talk unit (microphone)  1723 , which is constituted of a microphone of the bone conduction contact type, at the contact unit with the aforementioned bones in the left temple unit  2184  of the eyeglasses makes it possible to pick up the audio of the speaking party by bone conduction. Dividing the cartilage conduction vibration unit  1826  and the outgoing-talk unit (microphone)  1723 , constituted of a microphone of the bone conduction contact type, to the left and right temple units  2182  and  2184 , as in  FIG. 36 , makes it possible to prevent the microphone of the bone conduction contact type from picking up the vibration from the cartilage conduction vibration unit  1826 . 
     In the twenty-third embodiment of  FIG. 36  or a modification example as described above, it is also possible to omit the configuration related to 3D display from the lens unit  2186  and to make an ordinary eyeglasses configuration with only the right lens  2110  and left lens  2114 . 
     On the other hand, the following is another possible modification example, for the twenty-fifth embodiment of  FIG. 38 . Specifically, since the twenty-fifth embodiment is configured as the viewing eyeglasses  2381 , the sound source of the stereo audio information resides in the 3D television  2301 , and the right-ear cartilage-conduction vibration unit  2324  and the left-ear cartilage-conduction vibration unit  2326  are made to vibrate on the basis of the audio signal received by the infrared communication unit  2387 . However, when the configuration is instead such that a stereo audio signal unit serving as the sound signal source unit of the stereo audio information, and an audio memory for providing data thereto, are housed in the eyeglasses primary unit  2386  or one of the right temple unit  2382  and the left temple unit  2384  of  FIG. 38 , or are divided and then housed in both, then the present invention can be configured as an independent portable music player. Calling on  FIG. 38  to facilitate understanding of the configuration of such a modification example, the aforementioned stereo audio signal unit and audio memory for providing data thereto are to be included in the controller  2339 . In the case of this modification example, there is no need for a link with the 3D television  2301 ; therefore, instead of the right shutter  2358 , the left shutter  2359 , and the shutter drive unit  2357  in  FIG. 38 , a right lens and left lens of ordinary eyeglasses such as in the twenty-third embodiment of  FIG. 36  are arranged on the eyeglasses primary unit  2386 . 
     In the case of the above-described modification example in which the right lens and left lens are arranged at the eyeglasses primary unit  2386  to make ordinary eyeglasses, the controller, the audio drive unit, the infrared communication units, the power supply unit, and the other respective constituent elements arranged at the eyeglasses primary unit  2386  in  FIG. 38  may be divided and arranged at the right temple unit and the left temple unit as appropriate, as in the twenty-third embodiment of  FIG. 36 , thereby preventing any increase in the size of the eyeglasses primary unit  2386 . The infrared communication unit  2387  in the modification example is responsible for functions such as inputting sound source data from a PC or other external sound source data holding device. Using a handheld remote control or the like, the infrared communication unit  2387  can be made to function as a wireless communication unit for adjusting the volume from the right-ear cartilage-conduction vibration unit  2324  and the left-ear cartilage-conduction vibration unit  2326 , or for adjusting the balance of the left and right vibration output. It is furthermore possible to receive the audio information of a mobile telephone when the portable music player is linked to the mobile telephone. In such a case, when the portable music player is provided with an air conduction microphone or a bone conduction microphone, the portable music player can be made to function as a device of the mobile telephone used for incoming talk or outgoing talk made with an external party. 
     The above-described innovative arrangement of the constituent elements to the eyeglasses primary unit  2386  and to the right temple unit  2382  and left temple unit  2384  is not to be limited to the aforementioned modification example. For example, the controller  2339 , the infrared communication unit  2387 , the power supply unit  2348 , the right audio drive unit  2335 , and the left audio drive unit  2336  may also be divided and arranged in the right temple unit  2382  and the left temple unit  2384  as appropriate in the case of the actual viewing eyeglasses  2381  in the twenty-fifth embodiment of  FIG. 38 . 
     Twenty-Sixth Embodiment 
       FIG. 41  is a perspective view of the twenty-sixth embodiment according to an aspect of the present invention, and is configured as a mobile telephone. A mobile telephone  2401  of the twenty-sixth embodiment, similarly with respect to that of the modification example of the tenth embodiment depicted in  FIG. 40 , is an integrated type with no moving parts, and is configured as a “smartphone”, which has the large-screen display unit  205  provided with GUI functions. There is much in common with the structure thereof, and so corresponding portions have been given like reference numerals as in  FIG. 40 , and a description has been omitted. Similarly with respect to the tenth embodiment and the modification example thereof, “upper part” in the twenty-sixth embodiment also does not signify a separated upper part but rather signifies the portion at the top of the integrated structure. 
     A point of difference in the twenty-sixth embodiment from the modification example of the tenth embodiment illustrated in  FIG. 40  lies in that the vibration of the cartilage conduction vibration source  925  has a dual purpose as a vibration source for creating a feedback sensation for a touch operation in the touch panel function of the large-screen display unit  205 . More specifically, a vibration isolation material  2465  made of a vinyl system, a urethane system, or another system is provided between the cartilage conduction vibration source  925  and the configuration located therebelow (the large-screen display unit  205 ), the configuration being such that an audio signal from the cartilage conduction is prevented from being likely to be transmitted to the large-screen display unit  205  or the like, due to the difference in acoustic impedance or the like. On the other hand, when the large-screen display unit  205  is touched and any type of input from the touch panel function thereof is thereby accepted, the cartilage conduction vibration source  925  is made to vibrate at a low frequency at or below the audible range, in order to provide feedback to the finger that has touched the same. The vibration frequency is selected to be a frequency that substantially matches the resonance frequency of the vibration isolation material  2465 ; therefore, the vibration isolation material  2465  resonates due to the vibration of the cartilage conduction vibration source  925 , which vibration is then transmitted to the large-screen display unit  205 . The vibration isolation material  2465 , which prevents vibration in the audio region, thus functions as a vibration transmission material for low-frequency vibration for feedback. Low-frequency vibration can thereby be transmitted to the finger that touched the large-screen display unit  205 , and it can be known that the touch input has been accepted. To prevent conflation of the impact of the touch operation itself with the feedback vibration in response thereto, the cartilage conduction vibration source  925  is provided with a predetermined delay from the moment of touch, and is made to provide the feedback vibration after the touch impact has settled. 
     The twenty-sixth embodiment is provided with an operation button  2461 , which is used for operations such as turning the touch panel function of the large-screen display unit  205  on and off. Also, for the sake of simplifying the drawings, the configuration of the twenty-sixth embodiment omits the cartilage conduction output unit  963 , which has been provided to the modification example of the tenth embodiment illustrated in  FIG. 40 ; however, same can be provided as desired. 
       FIG. 42  is a block diagram of the twenty-sixth embodiment; identical portions have been given like reference numerals to those in  FIG. 41 , and a description thereof has been omitted. The configuration of the block diagram in  FIG. 42  has many points in common with the block diagram of the fourth embodiment in  FIG. 8 , and can call on the configuration of the conceptual block diagram of the elements in  FIG. 9 ; therefore, parts of the configuration in common with  FIG. 8  have been given like reference numerals and a description thereof has been omitted. 
     The large-screen display unit  205  of  FIG. 42  is illustrated as having a touch panel  2468 , and a touch panel driver  2470 , which is controlled by a controller  2439  and drives the touch panel  2465 ; however, this is not specific to the twenty-sixth embodiment, but rather is shared with other embodiments in which the large-screen display unit  205  has a touch panel function, and has merely been omitted from the diagrams of the other embodiments in order to avoid complication.  FIG. 42  illustrates vibration isolation materials  2465  respectively for the portions of the cartilage conduction vibration source  925  and the touch panel  2468 , but this has been described in such a manner merely because of the space limitations of the block diagram. The vibration isolation material  2465  is the same, and the description does not mean that it is separated and provided to respective positions on the cartilage conduction vibration source  925  and the touch panel  2468 . In other words, the intended illustration in  FIG. 42  is that the vibration isolation material  2465  resonates due to the low-frequency vibration of the cartilage conduction vibration source  925 , which vibration is transmitted to the touch panel  2468 . 
     As illustrated in  FIG. 42 , the twenty-sixth embodiment is provided with a low-frequency source  2466  for generating a drive signal of a frequency that substantially matches the resonance frequency of the vibration isolation material  2465 ; the controller  2439  instructs that a low frequency be outputted from the low-frequency source  2466  after a predetermined delay has elapsed from when the touch panel driver  2470  senses the touch of a finger and accepts the input. The phase adjustment mixer unit  2436  drives the cartilage conduction vibration source  925  on the basis of a signal from the telephone function unit  45  in a call state; however, the signal from the telephone function unit  45  being blocked during a non-call operation state in which the touch panel  2468  is operated, the cartilage conduction vibration source  925  is instead driven on the basis of a signal from the low frequency source  2466 . However, in a call state, the phase unit adjustment mixer unit  2436  blocks the signal from the low frequency source  2466 . 
     The function of the controller  2439  of  FIG. 42  in the twenty-sixth embodiment calls on the flow chart of the fourth embodiment in  FIG. 10 . Also, the dual purpose of the cartilage conduction vibration source  925  as a touch operation feedback sensation vibration source, which is a feature of the twenty-sixth embodiment, can be understood as a detailed function of step S 42  in  FIG. 10 . 
     As described above,  FIG. 43  serves to provide a detailed illustration of step S 42  in  FIG. 10 ; when the flow starts, step S 222  first has a check for whether a non-call operation has been performed. This step is similar to step S 6  in the first embodiment of  FIG. 4 , and is a check for the presence or absence of an e-mail operation and/or Internet operation, as well as other operations in which radio operations are not used, such as various settings and also downloaded games, and other non-call operations. Then, when there has been such an operation, the flow proceeds to step S 224 , in which there is performed a check for whether or not the touch panel  2468  is in a non-sensing state. When a non-sensing state is not in effect, the cartilage conduction vibration unit, including the cartilage conduction vibration source  925 , is turned on in step S 226 . On the other hand, in a case in which it is detected in step S 224  that the touch panel  2468  is in a non-sensing state, a non-call operation signifies one by the operation button  2461 , and the flow therefore moves on to step S 228 , in which there is button setting processing corresponding to the operation. Subsequently, in step S 230 , there is performed a check for whether the touch panel  2468  has been set to be activated by the button operation; when this is true, the flow moves on to step S 226 . However, in either a case in which there is no detection in step S 222  of a non-call operation, or a case in which there is no detection in step S 230  of a setting to activate the touch panel  2468 , the flow is immediately terminated. 
     When the cartilage conduction vibration unit is turned on in step S 226 , the flow proceeds to step S 232 , in which the phase adjustment mixer unit  2436  is controlled to sever the output from the telephone function unit  45 ; in step S 234 , the output of the low frequency source  2466  is connected to the cartilage conduction vibration source  925 , and the flow arrives at step S 236 . In step S 236  there is a check for the presence or absence of a touch panel operation; when there is a touch panel operation, the flow proceeds to step S 238 , and there is response processing in accordance with the operation. The flow then proceeds to step S 240 , in which a predetermined period of delay (for example, 0.1 seconds) is allowed to pass, and the flow moves on to step S 242 . In step S 242 , a low frequency is outputted from the low frequency source  2466  for a predetermined period of time (for example, 0.5 seconds), and the operation sensation is fed back to the finger with which the operation is performed; the flow then proceeds to step S 244 . 
     In step S 244 , there is performed a check for whether the touch panel  2468  has been in an operation-less state for a predetermined period of time (for example, 3 seconds) or longer after the latest touch panel operation; when this is not true, the flow returns to step S 236 . Afterwards, steps S 236  to S 244  are repeated as long as the touch panel  2468  is continuously operated for a predetermined period of time; the touch panel input and the operation sensation feedback by the cartilage conduction vibration source  925  are continued. 
     On the other hand, when there is a detection in step S 244  that the touch panel  2468  has remained in an operation-less state for the predetermined period of time or longer, the flow moves on to step S 246 , in which the cartilage conduction vibration unit is turned off; in step S 248 , the phase adjustment mixer unit  2436  is further controlled and the output from the telephone function unit  45  is connected to the cartilage conduction vibration source  925 ; and in step S 250 , the output of the low frequency source  2466  is severed, the flow then terminating for the time being. The flow thereafter being executed in accordance with  FIG. 10 , when no call is detected in step S 44  of  FIG. 10 , the flow immediately moves to step S 34 ; when the primary power supply is not off, the flow then returns to step S 42 ; therefore, the flow in  FIG. 43  is resumed. There is accordingly a swift return to step S 236  whenever the operation of the touch panel lasts for the predetermined period of time and the flow in  FIG. 43  from step S 244  terminates, and the touch panel input and the operation sensation feedback by the cartilage conduction vibration source  925  can be continued. 
     The implementation of the present invention is not to be limited to the aforementioned embodiments; various modifications are possible. For example, the vibration isolation material  2465  in the twenty-sixth embodiment is not limited to a material having a band-pass filter function for transmitting the vibration of the resonance frequency, and may be a material having a low-pass filter function for blocking the vibration from the telephone function unit  45  at or above a predetermined frequency, which is in the audio signal region, and for transmitting the vibration of the low frequency source  2466  for the touch operation feedback, which is in a lower frequency region. 
     Twenty-Seventh Embodiment 
     The following calls on  FIGS. 41 to 43  in the twenty-sixth embodiment to provide a description of the twenty-seventh embodiment of the present invention. In this case, the “touch panel  2468 ” in  FIG. 42  is to be read as a “motion sensor  2468 ,” and the “touch panel driver  2470 ” is to be read as a “motion sensor driver  2470 .” The twenty-seventh embodiment, as with the twenty-sixth embodiment, is configured such that, in a case in which the cartilage conduction vibration source  925  has a dual purpose for a touch operation in the GUI function of the large-screen display unit  205 , a configuration is presented in that the cartilage conduction vibration source, rather than merely being utilized as a low frequency output element for touch sensation feedback, is additionally used as an impact input element for detecting a touch on the mobile telephone  2401 . For this purpose, the cartilage conduction vibration source  925  in the twenty-seventh embodiment is constituted of a piezoelectric bimorph element. The specific configuration for the dual purpose of the piezoelectric bimorph element as an impact input element can be configured calling on the block diagram of the fourth embodiment described in  FIG. 9  and on the flow chart of the eighteenth embodiment described in  FIG. 31 . 
     More specifically, the GUI function of the large-screen display unit  205  in the twenty-seventh embodiment, as mentioned above, is configured to make use not of a contact-type touch panel, but rather of a motion sensor  2468  for contactless detection of the motion of a finger in the vicinity of the large-screen display unit  205 . The impact detection function of the cartilage conduction vibration source  925 , which comprises a piezoelectric bimorph element, is used as an impact sensor for detecting the touch of a finger (corresponding to the “click” of a mouse or the like) for determining a function that is selected without contact. As a more specific example, scrolling and the selecting of an icon on the large-screen display unit  205  are conducted by the detection of the contactless motion of a finger, and the touch impact on the mobile telephone  2401  corresponding to a “click” operation is detected by the dual purpose of the piezoelectric bimorph element, whereby an operation of “CONFIRM” or “ENTER” is performed. The touch at this time is not on the large-screen display unit  205  but rather may be at any desired place on the outer wall of the mobile telephone, and therefore a “click” operation can be performed without leaving a fingerprint on the large-screen display unit  205 . 
     The vibration isolation material  2465  in the twenty-seventh embodiment, which calls on  FIG. 41 , blocks the vibration from the telephone function unit  45  in the audio signal region, and transmits the transmittable components of the impact vibration in the band-pass filter region or low-pass filter region to the cartilage conduction vibration source  925 , which comprises a piezoelectric bimorph. A point in common with the twenty-sixth embodiment lies in that after the cartilage conduction vibration source  925  detects the touch impact of a finger, a low frequency is generated from the low frequency source  2466  after a predetermined period of delay has passed, and the cartilage conduction vibration source  925  is made to vibrate, providing feedback to the finger that performed the touch. Then, in such a case, there is a need to switch the piezoelectric bimorph element to function as an input element and function as an output element, but this switch can be performed utilizing the aforementioned period of delay. 
     The implementation of the present invention is not to be limited to the aforementioned embodiments; various modification examples are possible. For example, instead of the impact detection function of the piezoelectric bimorph element, the acceleration sensor  49  in  FIG. 42  may be used for detecting the click impact in the contactless-type motion sensor as in the twenty-seventh embodiment. Both the function of the acceleration sensor  49  and the impact detection function of the piezoelectric bimorph element may also be used in combination as appropriate. 
     The dual purpose of the cartilage conduction vibration source  925  as a low frequency vibration source, which is a feature of the twenty-sixth embodiment and the twenty-seventh embodiment, is also not limited to the purpose of providing touch sensation feedback to a finger, but rather can also have the purpose of a dual use as a vibrator for providing a noiseless notification of an incoming call to the mobile telephone  2401 . In such a case, as shall be apparent, the introduction of the vibration signal of the low frequency source  2466  to the cartilage conduction vibration source  925  is not a touch detection but rather a response to an incoming call signal, at which time a delay is unnecessary. The introduction of the vibration signal is repeated continuously (interspersed, for example, by an interval of 0.5 second in which vibration is stopped) for a comparatively long period of time (for example, 2 seconds). 
     Each of the various features indicated in each of the embodiments described above is not necessarily specific to an individual embodiment; the features of each of the embodiments can be combined or rearranged with the features of other embodiments as appropriate, wherever it is possible to make use of the advantages thereof. For example, it is possible to combine the aforementioned eyeglasses-type stereo portable music player described as a modification example of the twenty-fifth embodiment in  FIG. 38 , as an external incoming/outgoing-talk unit for a mobile telephone provided with such features as in the twenty-sixth embodiment or the twenty-seventh embodiment. In such a case, stereo playback from a sound source housed in the music player can be enjoyed, and also audio signals can be received from the sound source of the mobile telephone to enjoy stereo playback. A hands-free call with the mobile telephone can then be made using an air conduction microphone or bone conduction microphone housed in the eyeglasses-type portable music player. 
     Twenty-Eighth Embodiment 
       FIG. 44  relates to the twenty-eighth embodiment according to an aspect of the present invention;  FIG. 44A  is a perspective view illustrating a part of the upper end side thereof, and  FIG. 44B  is a cross-sectional view illustrating the B-B cross-section of  FIG. 44A . The twenty-eighth embodiment is configured as a mobile telephone  2501 , and is similar to the fourth embodiment illustrated in  FIG. 7 ; the vibration of a cartilage conduction vibration source  2525  is transmitted to a vibration conductor  2527 , the two end parts thereof being in respective contact with the right tragus and the left tragus, whereby sound can be listened to by cartilage conduction. Accordingly, the “upper part” in the twenty-eighth embodiment of  FIG. 44  does not signify a separated upper part but rather signifies the portion at the top of the integrated structure. 
     A point of difference in the twenty-eighth embodiment of  FIG. 44  from the fourth embodiment illustrated in  FIG. 7  lies in the holding structure for holding the cartilage conduction vibration source  2525  and the vibration conductor  2527  in the mobile telephone  2501 . For the configuration for inputting an audio signal into the cartilage conduction vibration source  2525  and the like there can be appropriately used the configuration according to the first to twenty-seventh embodiments, and therefore an illustration and description thereof has been omitted. The cartilage conduction vibration source  2525  of the twenty-eighth embodiment is configured as a piezoelectric bimorph element (and is hereinafter referred to as the “piezoelectric bimorph element  2525 ”), but, as in  FIG. 44B , the structure piezoelectric bimorph element  2525  is one in which piezoelectric ceramic sheets  2598 ,  2599  are respectively bonded to the two sides of a metal sheet  2597 , the circumference thereof being hardened using a resin. Vibration in this structure goes in the Y-Y′ direction illustrated in  FIG. 44B . Accordingly, the resin surface of the piezoelectric bimorph element  2525  has a larger Y-Y′ direction component of vibration, and a smaller X-X′ direction component of vibration. 
     Assuming the above-described structure for the piezoelectric bimorph element  2525 , the holding structure of the twenty-eighth embodiment is such that, as is clear from the cross-sectional view of  FIG. 44B , the piezoelectric bimorph element  2525  is sandwiched from the X-X′ direction, which has a smaller vibration component, by a holding body  2516 . The holding body  2516  and the piezoelectric bimorph element  2525  are joined using a bonding agent, and the holding body  2516  is rigidly coupled to the mobile telephone  2501 . On the other hand, regarding the Y-Y′ direction of the piezoelectric bimorph element  2525 , a gap  2504  is provided in  FIG. 44B  in between the holding body  2516  and the inner surface side serving as the right side; vibration is unrestrictedly permitted in the Y-Y′ direction in the piezoelectric bimorph element  2525 , and the vibration component therein is less likely to be transmitted to the holding body  2516 . A bonding agent is also used to join the vibration conductor  2527  rigidly to the outer surface side serving as the left side in  FIG. 44B  in the Y-Y′ direction of the piezoelectric bimorph element  2525 . The mobile telephone  2501  also has an opening part  2501   a  for exposing the vibration conductor  2527 . Then, the vibration isolation material  2565  comprising an elastic body based on vinyl, urethane, or another substance is used to fill in the space between the vibration conductor  2527  and the holding body  2516 , and the opening part  2501   a  of the mobile telephone  2501 . Vibration is unrestrictedly permitted in the Y-Y′ direction of the vibration conductor  2527 , and the vibration component of the piezoelectric bimorph element  2525  is less likely to be transmitted to the holding body  2516  and the mobile telephone  2501 . In the description above, the gap  2504  may also be configured so as to be filled in by an elastic body similar to the vibration isolation material  2565 . 
     Due to the holding structure as described above, the force of the hand holding the mobile telephone  2501  is rigidly applied to the vibration conductor  2527 , whereby the contact with the right tragus or left tragus and the pressure thereof can be easily controlled. Because the structure is such that vibration is unrestrictedly permitted in the Y-Y′ direction of the vibration conductor  2527 , the vibration conductor  2527  vibrates efficiently and the vibration thereof is transmitted to the cartilage of the ear; also, the vibration of the vibration conductor  2527  can be effectively prevented from being transmitted to the mobile telephone  2501  and generating unneeded air conduction. 
       FIG. 45  is a cross-sectional view relating to modification examples of the twenty-eighth embodiment of  FIG. 44 .  FIG. 45A  is a cross-sectional view of a first modification example, and is illustrated in conformity with  FIG. 44B , portions in common being given like reference numerals. Similarly,  FIG. 45B  illustrates a cross-sectional view of a second modification example. In the first modification example, illustrated by  FIG. 45A , the gap  2504  is stretched over the entire space between the holding body  2516  and the piezoelectric bimorph element  2525 , and an auxiliary holding unit  2506  for holding the piezoelectric bimorph element  2525  between the two from the X-X′ direction is provided. The rigid material of the auxiliary holding unit  2506  is selected to have a different acoustic impedance from either both of or at least one of the holding body  2516  and the piezoelectric bimorph element  2525 . The auxiliary holding unit  2506  may be an elastic body provided that there is no problem in terms of holding force. The auxiliary holding unit  2506  is configured to be arranged at the center part to avoid the vibration surface of the Y-Y′ direction in the piezoelectric bimorph element  2525 ; therefore, even with an integrated molding of the same material, as a part of the holding body  2516 , there is a more pronounced effect relative to  FIG. 44(B)  in permitting vibration in the Y-Y′ direction in the piezoelectric bimorph element  2525  and in reducing the transmission of vibration to the mobile telephone  2501 . 
     The second modification example of  FIG. 45B  also takes a configuration in which the gap  2504  is spread over the entire space between the holding body  2516  and the piezoelectric bimorph element  2525 ; however, a plurality of screws  2508  provided to important points in the middle part of the piezoelectric bimorph element  2525  are used to sandwich the piezoelectric bimorph element  2525  from the X-X′ direction. The screws  2508  are threaded such that the sharp tips thereof are slightly wedged into the surface of the piezoelectric bimorph element  2525 , ensuring the holding of the piezoelectric bimorph element  2525 . 
       FIG. 46  is a cross-sectional view relating to yet further modification examples of the twenty-eighth embodiment of  FIG. 44 .  FIG. 46A  is a cross-sectional view of a third modification example, and, similarly with respect to  FIG. 45 , is illustrated in conformity with  FIG. 44B , shared portions being given shared reference numerals. Similarly,  FIG. 46B  illustrates a cross-sectional view of a fourth modification example. In the third modification example illustrated in  FIG. 46A , the surface of the piezoelectric bimorph element  2525  is molded using a resin such that a concavity  2580  is formed, and a convexity corresponding thereto is integrally molded in the holding body  2516 . The engagement between these convex and concave parts ensures that the piezoelectric bimorph element  2525  is held by the holding body  2516 . Upon assembly, the slight elasticity of the holding body  2516  may be utilized for fitting of the piezoelectric bimorph element  2525 ; alternatively, the configuration may be such that the holding body  2516  is constituted as two divided bodies, and after the piezoelectric bimorph element  2525  is sandwiched therebetween, same are integrally screwed together. 
     In the fourth modification example illustrated by  FIG. 46B , the surface of the piezoelectric bimorph element  2525  is molded with a resin such that a convexity  2590  is formed, and a concavity corresponding thereto is integrally molded in the holding body  2516 . Then, similarly with respect to  FIG. 46A , the engagement of these convex and concave parts ensures the holding of the piezoelectric bimorph element  2525  by the holding body  2516 . Upon assembly, similarly with respect to  FIG. 46A , the configuration may be such that the piezoelectric bimorph element  2525  may be fitted using the slight elasticity of the holding body  2516 , or such that the holding body  2516  is constituted as two divided bodies, and after the piezoelectric bimorph element  2525  is sandwiched therebetween, the same are integrally screwed together. 
     Twenty-Ninth Embodiment 
       FIG. 47  relates to the twenty-ninth embodiment according to an aspect of the present invention;  FIG. 47A  is a perspective view illustrating a part of the upper end side thereof, and  FIG. 47B  is a perspective view illustrating a part of the upper end side in a modification example thereof. The twenty-ninth embodiment has a holding structure that is substantially the same as that of the twenty-eighth embodiment in  FIG. 44 , but has a different configuration, in which the vibration conductor in contact with the right tragus or the left tragus is exposed to the surface of the mobile telephone from openings  2501   b  and  2501   c  provided to the outer wall of the mobile telephone  2501 . Portions in common with  FIG. 44  are accordingly given the same reference numerals, and a description thereof has been omitted. The following provides only a description of the disparities relative to the twenty-eighth embodiment of  FIG. 44 . 
     The twenty-eighth embodiment of  FIG. 44  is configured such that the vibration conductor  2527  is exposed in a strip on the entire upper end part of the mobile telephone  2501 , both end parts thereof being in contact with the right tragus and left tragus respectively and also being capable of being in contact with the ear cartilage over a broad surface area. By contrast, the twenty-ninth embodiment of  FIG. 47A  is configured such that the vibration conductor is divided into a right ear vibration conductor  2524  and a left ear vibration conductor  2526 , which are respectively bonded to the two ends of the piezoelectric bimorph element  2525 . Then, only a portion of the separated right ear vibration conductor  2524  and left ear vibration conductor  2526  is made to be respectively exposed from the opening parts  2501   b  and  2501   c  of the two corner parts at the top end of the mobile telephone  2501 . For this reason, the vibration isolation material  2565  for filling in the space between the mobile telephone  2501  and the right ear vibration conductor  2524  and left ear vibration conductor  2526  is also provided in respective separations. 
     On the other hand, the modification example of the twenty-ninth modification example illustrated by  FIG. 47B  is configured such that only the left ear vibration conductor  2526  is bonded to the piezoelectric bimorph element  2525 . Then, only a portion of the left ear vibration conductor  2526  is exposed from the opening part  2501   b  of the corner part at the top end of the mobile telephone  2501 . The vibration isolation material  2565  for filling in the space between the left ear vibration conductor  2526  and the mobile telephone  2501  is provided only to the left side corner part of the mobile telephone  2501 . Also, the modification example of the twenty-ninth embodiment illustrated by  FIG. 47B , although simplifying the configuration of  FIG. 47A  and being configured for dedicated left ear usage, is also capable of being configured such that the vibration conductor is exposed from an opening part provided to the right corner part for a configuration as a mobile telephone especially for right ear usage. As yet another modification of the modification example of the twenty-ninth embodiment illustrated by  FIG. 47B , the piezoelectric bimorph element can also be directly exposed from the opening part, without the vibration conductor being interposed, in a case in which the surface of the piezoelectric bimorph element is fashioned into a shape suited for the outer surface of the mobile telephone. Such a modification is also possible in the twenty-ninth embodiment illustrated by  FIG. 47A  and in the twenty-eighth embodiment illustrated by  FIG. 44 . 
     Thirtieth Embodiment 
       FIG. 48  relates to the thirtieth embodiment according to an aspect of the present invention;  FIG. 48A  is a perspective view illustrating a part of the upper end side thereof, and  FIG. 48B  is a cross-sectional view illustrating the B-B cross-section of  FIG. 48A . The thirtieth embodiment is configured as a mobile telephone  2601  and is similar to the thirteenth embodiment illustrated by  FIG. 24  and/or the fourteenth embodiment illustrated by  FIG. 25 . The cartilage conduction vibration unit is arranged on the side surface of the mobile telephone. The thirtieth embodiment of  FIG. 48 , similarly with respect to the twenty-eighth embodiment of  FIG. 44 , also features a holding structure for permitting vibration for ear cartilage conduction in the piezoelectric bimorph element and for reducing the transmission of vibration to the mobile telephone; therefore, portions in common with the twenty-eighth embodiment have been given like reference numerals, and a description thereof has been omitted. Another point of similarity with the twenty-eighth embodiment lies in the configuration for inputting an audio signal to the cartilage conduction vibration source  2525 , of which a depiction and description has been omitted. 
     The thirtieth embodiment of  FIG. 48  is configured such that the piezoelectric bimorph element  2525  is fitted into the side surface of the mobile telephone, but, as illustrated by  FIG. 48B , the interior of the fitted-in part is curved; as a result thereof, a ridge part  2525   a  of the piezoelectric bimorph element  2525  is brought into contact with the inner surface of the curved part of the mobile telephone  2601 . Due to such contact, the piezoelectric bimorph element  2525  is positioned in the fitting-depth direction, reinforcing the holding force relative to the direction pushing in on the piezoelectric bimorph element  2525 . A crescent gap  2604  is created in the Y-Y′ direction of the piezoelectric bimorph element  2525  due to the contact structure as described above, permitting free vibration. The piezoelectric bimorph element  2525  is fundamentally held from the X-X′ direction in the thirtieth embodiment as well. For the sake of simplicity, the illustration in  FIG. 48  is such that a part of the integral structure of the mobile telephone  2601  serves as the holding structure, but the configuration may also be such that a structure such as the holding body  2516  of the twenty-eighth embodiment and of the twenty-ninth embodiment is utilized, and anchored on the mobile telephone  2601 . The structure can otherwise be understood with reference to  FIG. 44 , and therefore a description thereof has been omitted. The various modification examples illustrated in  FIGS. 45 and 46  can also be applied to the thirtieth embodiment of  FIG. 48 . 
     Thirty-First Embodiment 
       FIG. 49  relates to a thirty-first embodiment according to an aspect of the present invention;  FIG. 49A  is a longitudinal sectional view illustrating a part of the upper end side thereof.  FIG. 49B  is a transverse cross-sectional view of the same portions, and can be understood to be similar to  FIG. 48B . The thirty-first embodiment is configured as a mobile telephone  2701 , and is similar to the thirtieth embodiment illustrated in  FIG. 48 ; the cartilage conduction vibration unit is arranged on the side surface of the mobile telephone. The feature thereof lies in the holding structure for permitting vibration for ear cartilage conduction in the piezoelectric bimorph element and for reducing the transmission of vibration to the mobile telephone; therefore, portions in common with the thirtieth embodiment of  FIG. 48  have been given like reference numerals, and a description thereof has been omitted. Another point of similarity with the thirtieth embodiment lies in the configuration for inputting an audio signal to the cartilage conduction vibration source  2525  and the like, for which a depiction and description has been omitted. 
     A point of difference in the thirty-first embodiment of  FIG. 49  from the thirtieth embodiment of  FIG. 48  lies in the holding structure of the piezoelectric bimorph element  2525 . The piezoelectric bimorph element  2525 , similarly with respect to the thirtieth embodiment, takes a structure in which it is fitted into a groove in the side surface of the mobile telephone  2701 , but as is clear from the longitudinal cross-sectional view of  FIG. 49A  and the transverse cross-sectional view of  FIG. 49B , the inner surface of the groove becomes a corrugated surface  2794 ; as a result thereof, the piezoelectric bimorph element  2525  is held by a plurality of apices of the corrugated surface  2794 , and a plurality of gaps  2704  are created in between the two. For the sake of simplicity, the illustration in  FIG. 49  is also such that a part of the integral structure of the mobile telephone  2701  serves as the holding structure, but the configuration may also be one in which there is adopted a structure such as the holding body  2516  of the twenty-eighth embodiment and of the twenty-ninth embodiment, and same is anchored to the mobile telephone  2701 . This is also a point of similarity with modification examples to be described later. 
       FIG. 50  is a longitudinal cross-sectional view illustrating modification examples of the thirty-first embodiment, and can be understood with reference to  FIG. 49A .  FIG. 50A  is a first modification example, wherein a vibration conductor  2727  (silicon, urethane, or the like) is provided to the side of the piezoelectric bimorph element  2525  that comes up against the ear cartilage.  FIG. 50B  is a second modification example. A vibration isolation material  2765  is interposed between the piezoelectric bimorph element  2525  and the mobile telephone  2701 , and the surface at which the vibration isolation material  2765  comes up against the piezoelectric bimorph element  2525  serves as the corrugated surface  2795 . A modification example that combines the vibration conductor  2727  in the first modification example of  FIG. 50A  with the vibration isolation material  2765  in the second modification example of  FIG. 50B  is also possible. 
     Thirty-Second Embodiment 
       FIG. 51  is a perspective view of a thirty-second embodiment according to an aspect of the present invention. The thirty-second embodiment is configured as a piezoelectric bimorph element  2525  suited for use in, for example, the mobile telephone  2501  of the twenty-ninth embodiment illustrated in  FIG. 47A .  FIG. 51A  is an external perspective view of the piezoelectric bimorph element  2525  of the thirty-second embodiment, and  FIG. 51B  is a transparent perspective view thereof. For convenience of illustration,  FIG. 51  has been drafted such that the piezoelectric bimorph element  2525  is rotated 90 degrees from the state of  FIG. 47A , where the Y-Y′ direction becomes the vertical direction. 
     The holding body  2516  of the twenty-ninth embodiment of  FIG. 47A , similarly with respect to that of the twenty-eighth embodiment of  FIG. 44 , sandwiches the piezoelectric bimorph element  2525  from the X-X′ direction illustrated in  FIG. 44B ; vibration in the Y-Y′ direction is unrestrictedly permitted, and the vibration component is prevented from being transmitted to the holding body  2516 . Furthermore, the holding body  2516  is configured so as to sandwich the middle portion of the piezoelectric bimorph element  2525 , in which the right ear vibration conductor  2524  and the left ear vibration conductor  2526  are respectively bonded to both ends. 
     The piezoelectric bimorph element  2525  illustrated in  FIG. 51  assumes a configuration permitting the holding of the middle part of the piezoelectric bimorph element  2525  from the X-X′ direction, as described above. Specifically, as illustrated in  FIG. 51A , the piezoelectric bimorph element  2525  of the thirty-second embodiment is configured such that electrodes  2597   a  and  2598   a  for inputting a drive signal are positioned at the middle portion of the piezoelectric bimorph element  2525 . Both end portions of the piezoelectric bimorph element  2525  are thereby released from a wired connection, and free vibration is permitted. Moreover, the direction in which the electrodes  2597   a  and  2598   a  project out is configured so as to assume a direction along the Y-Y′ direction of the vibration direction. Thereby, when the middle portion of the piezoelectric bimorph element  2525  is sandwiched from the X-X′ direction, the electrodes  2597   a  and  2598   a  are not obstructive and there is no need to provide the holding body  2516  with a special configuration, despite the arrangement of the electrodes  2597   a  and  2598   a  at the middle portion. 
     To permit such an arrangement of the electrodes, the piezoelectric bimorph element  2525  is configured, as illustrated in  FIG. 51B , such that the electrode  2597   a , which is drawn out from the middle portion of a metal sheet  2597 , is curved upward at 90 degrees, and the electrodes  2598   a , which are drawn out from piezoelectric ceramic sheets  2598  and  2599 , and respectively connected to each one, are also curved upward at 90 degrees, each projecting from the upper surface of the resin. The middle portion of the piezoelectric bimorph element  2525  can thereby be readily supported sandwiched from the X-X′ direction, without an electrode projecting out to the X-X′ direction. 
     Also, as a modification of  FIG. 51 , the configuration can also be such that each of the electrode  2597   a  that is drawn out from the middle part of the metal sheet  2597  and the electrodes  2598   a  that are drawn out from the middle parts of the piezoelectric ceramic sheets  2598  and  2599  project out from the side surface of the resin. In such a case, to sandwich and support the middle portion of the piezoelectric bimorph element  2525  from the X-X′ direction, the holding body  2516  is provided with a void for avoiding a portion that would interfere with the electrodes, and connects a signal line; alternatively, a socket structure is provided to the inner side of the holding body  2516  and a connection is made with the electrodes. In such a case as well, the holding body  2516  must be provided with a special configuration; however, no change is needed to provide the electrodes  2597   a  and  2598   a  to the middle part, and therefore it is possible to benefit from the advantage of releasing the two end portions of the piezoelectric bimorph element  2525  from wired connections and enabling free vibration. 
     Thirty-Third Embodiment 
       FIG. 52  relates to a thirty-third embodiment according to an aspect of the present invention, and is configured as a mobile telephone  2801 .  FIG. 52A  is a transparent perspective view in which a part of the upper end side thereof is viewed from the rear, and  FIG. 52B  is a transparent perspective view in which a part of the upper end side in the modification example thereof is viewed from the side surface of the opposite side. The thirty-third embodiment illustrated in  FIG. 52A  has a holding structure that is substantially similar to that of the twenty-ninth embodiment in  FIG. 47A , but has a different configuration in which a pair of vibration conductors  2824  and  2826  that are in contact with the ear cartilage are exposed on the surface of the mobile telephone. 
     Specifically, the vibration conductors  2524  and  2526  in the twenty-ninth embodiment of  FIG. 47  are directly exposed at the upper corner parts of the mobile telephone  2501 . By contrast, in the thirty-third embodiment of  FIG. 52 , corner parts  2801   d ,  2801   e  serve as a part of a sufficiently strong outer wall of the mobile telephone  2801  itself, and each of the vibration conductors  2824  and  2826  are exposed on the display surface side of the mobile telephone  2801  in such as form as to be guarded by the corner parts. A detailed description of this exposed state and the significance thereof will be provided later. The configuration is otherwise shared with that of the twenty-ninth embodiment of  FIG. 47 ; therefore, in  FIG. 52  portions that are in common have been given like reference numerals, and a description thereof has been omitted. The thirty-third embodiment also serves as an example of the implementation of the piezoelectric bimorph elements  2525  illustrated in the thirty-second embodiment, and also illustrates the positions of the electrodes  2597   a  and  2598   a  together. 
     In the modification example of the thirty-third embodiment in  FIG. 52B , the same configuration as the vibration unit described with reference to  FIG. 52A  is attached such that the side surface of the mobile telephone  2801  is made to vibrate as in the thirtieth embodiment of  FIG. 48  and/or the thirty-first embodiment of  FIG. 49 . In the modification example of the thirty-third embodiment in  FIG. 52B  as well, the vibration conductor  2824 , which is the upper of the pair of vibration conductors, is guarded by the sufficiently strong corner part  2801   d  of the mobile telephone  2801  and is exposed to the side surface of the mobile telephone  2801 . The vibration conductor  2826 , which is lower, is not originally positioned at a corner part and is therefore guarded naturally. 
       FIG. 53  is an external perspective view in which each of the thirty-third embodiment of  FIG. 52  and the modification example thereof is viewed from the front;  FIG. 53A  belongs to the thirty-third embodiment, and  FIG. 53B  belongs to the modification example thereof. The configuration in  FIG. 53  also has much in common with the twenty-sixth embodiment of  FIG. 41  and the like; therefore, portions that are in common have been given like reference numerals, and a description thereof has been omitted. 
     As is clear from  FIG. 53A , a pair of vibration conductors  2824  and  2826  are respectively exposed on the surface of the large-screen display unit  205  of a mobile telephone  2801  in such a form as to be respectively guarded by the corner parts  2801   d  and  2801   e  of the mobile telephone  2801 . Similarly with respect to the twenty-ninth embodiment of  FIG. 47 , a vibration isolation material  2865  is also used in the thirty-third embodiment of  FIG. 53A  to fill in the space between the pair of vibration conductors  2824  and  2826  and the mobile telephone  2801 . 
     Herein, a description will be provided for the significance of the aforementioned configuration of the thirty-third embodiment illustrated in  FIGS. 52 and 53 . The corner parts  2801   d  and  2801   e  of the mobile telephone  2801  are at sites that are suitable for coming up against the tragus or other ear cartilage, but are simultaneously also at sites that facilitate the direct application of impact when a drop or other event occurs. Accordingly, in a case assuming a configuration such as, for example, that of the twenty-ninth embodiment of  FIG. 47 , the vibration conductors  2524  and  2526 , the piezoelectric bimorph element  2525  to which same are bonded, the holding body  2516  thereof, and other vibration units must have a configuration that is resilient against collision. By contrast, according to the configuration of the thirty-third embodiment illustrated in  FIGS. 52 and 53 , the vibration conductors  2524  and  2526  are guarded by the original corner parts  2801   d  and  2801   e  of the mobile telephone  2801 ; therefore, a countermeasure for impacts is more readily realized than in the case of the twenty-ninth embodiment. 
     In the modification example of  FIG. 53B  as well, as is clear from the diagram, the vibration conductor  2824 , which is the upper of the pair of vibration conductors, is guarded by the corner part  2801   d  of the mobile telephone  2801  and is exposed to the side surface of the mobile telephone  2801 . The vibration conductor  2826 , which is lower, is positioned at a side surface that is less prone to the direct application of impact. Similarly with respect to the case of  FIG. 53A , the vibration isolation material  2865  is used to fill in the spaces between the pair of vibration conductors  2824  and  2826  and the mobile telephone  2801 . 
     In a case in which, as in the modification examples of the thirty-third embodiment illustrated in  FIGS. 52B and 53B , the vibration conductors  2824  and  2826  are provided to two points on the side surface (one point of which is in the vicinity of the upper part corner  2801 ), it becomes possible for both to come up against two points of the ear cartilage in the longitudinal direction. In such a case, when the space between the vibration conductor  2824  and the vibration conductor  2826  is on the order of 2 to 5 cm, the upper vibration conductor  2824  is also able to come up against the ear cartilage when the lower vibration conductor  2826  comes up against the tragus. As shall be apparent, the use such that the upper vibration conductor  2824  is brought up against the tragus for listening is discretionary. Similarly, in the case of the thirty-third embodiment illustrated in  FIGS. 52A and 53A  as well, the vibration conductors  2824  and  2826  can also be brought up against two points of the ear cartilage in the transverse direction. The divided use of the vibration conductor  2824  for abutting the right tragus and of the vibration conductor  2826  for abutting the right tragus, such as in the twenty-ninth embodiment of  FIG. 47 , is also discretionary. 
     In any event, abutting the ear cartilage at two points permits the energies of both the simultaneously vibrating vibration conductors  2824  and  2826  to be introduced to the ear cartilage; the transmission is therefore energy-efficient. On the other hand, in a case in which the mobile telephone  2801  is pushed strongly against the tragus to obtain the earplug bone conduction effect, the pushing on and obstructing of the tragus is more readily achieved by bringing merely a single vibration conductor at the corner part up against the tragus. 
     Thirty-Fourth Embodiment 
       FIG. 54  is a transparent perspective view relating to a thirty-fourth embodiment according to an aspect of the present invention, the embodiment being configured as a mobile telephone  2901 . The thirty-fourth embodiment is configured such that the side surface of the a mobile telephone  2901  is made to vibrate, as in the thirtieth embodiment of  FIG. 48  and/or the thirty-first embodiment of  FIG. 49 , but both side surfaces are made to be capable of vibrating so as to be able to support both the case of right-hand-held and the case of left-hand-held usage. In other words, the thirty-fourth embodiment of  FIG. 54  substitutes the pair of vibration conductors  2824  and  2826  in the thirty-third embodiment of  FIG. 52A  with a pair of vibration conductors  2924  and  2926  for a side surface arrangement; the vibration conductors  2924  and  2926  assume a vertically long shape so as to achieve contact with the ear cartilage over a broad range of the side surface. The holding structure of the piezoelectric bimorph element  2525  is shared with that of the thirty-third embodiment of  FIG. 52A , but a more detailed illustration has been omitted in order to avoid complication. 
     In the thirty-fourth embodiment, the color of the vibration conductors  2924  and  2926  is made to be different from the color of the outer wall of the mobile telephone  2901 , and the configuration may also be such that the user knows that the configuration is such that sound is listened to from the side surface and also knows what portion is thereupon brought up against the ear. On the other hand, in a case in which the user is notified that the configuration is such that sound is listened to from the side surface and what portion is thereupon brought up against the ear, there may be employed a design for implementing surface processing such that it is unknown whether the color of the vibration conductors  2924  and  2926  has been rendered as the same color as the color of the outer wall of the mobile telephone  2901 , and such that the boundary with the outer wall of the mobile telephone  2901  is further unknown. The configuration of the thirty-fourth embodiment is otherwise shared with that of, for example, the twenty-sixth embodiment of  FIG. 41 , and therefore portions that are in common have been given like reference numerals, and a description thereof has been omitted. 
     Thirty-Fifth Embodiment 
       FIG. 55  is a transparent perspective view relating to a thirty-fifth embodiment according to an aspect of the present invention, the embodiment being configured as a mobile telephone  3001 . The thirty-fifth embodiment is also configured such that the two side surfaces of the mobile telephone  3001  are made to vibrate across a broad range, similarly with respect to the thirty-fourth embodiment of  FIG. 54 . However, a point of difference from the thirty-fourth embodiment of  FIG. 54  lies in that a pair of piezoelectric bimorph elements  3024  and  3026  are arranged in a vertically long position such that each of the two side surfaces can be independently controlled. It accordingly becomes possible to cause only the one piezoelectric bimorph element that is being used to vibrate automatically, similarly with respect to the first to third embodiments described in  FIGS. 1 to 6 . The holding of the piezoelectric bimorph elements  3024  and  3026  can utilize the holding structures in each of the embodiments described in  FIGS. 44 to 52  and the like, as appropriate, and therefore a more detailed illustration has been omitted in order to avoid complexity. 
     The thirty-fifth embodiment may also be configured such that, when the piezoelectric bimorph elements  3024  and  3026  are arranged on the side surfaces, the piezoelectric bimorph elements  3024  and  3026  are covered with a material such as that of the vibration conductor  2527  in the thirtieth embodiment in  FIG. 48 , the color of the vibration conductor being made to be different from the color of the outer wall of the mobile telephone  3001 , such that the user learns that the configuration is such that sound is listened to from the side surface and knows what portion is thereupon brought against the ear. On the other hand, similarly with respect to the thirty-fifth embodiment, in a case in which the user is notified that the configuration is such that sound is listened to from the side surface and is notified of what portion is thereupon brought up against the ear, there may be employed a design for implementing surface processing such that it is unknown whether the color of the vibration conductor has been rendered as the same color as the color of the outer wall of the mobile telephone  3001 , and such that the boundary with the other side surface portion in the outer wall of the mobile telephone  3001  is unknown. The configuration of the thirty-fifth embodiment is otherwise shared with that of, for example, the twenty-sixth embodiment of  FIG. 41 , and therefore portions that are in common have been given like reference numerals, and a description thereof has been omitted. 
     Thirty-Sixth Embodiment 
       FIG. 56  is a transparent perspective view relating to a thirty-sixth embodiment according to an aspect of the present invention, and is configured as a mobile telephone  3101  and a mobile telephone  3201 . The configuration of the thirty-sixth embodiment of  FIG. 56  is substantially consistent with that of the thirty-fifth embodiment of  FIG. 55 , but the mobile telephone is configured as a left-handed mobile telephone  3101  illustrated in  FIG. 56A  and as a right-handed mobile telephone  3201  illustrated in  FIG. 56B  so as to provide the market with the ability to select either one. In other words, the left-handed mobile telephone  3101  of  FIG. 56A  is provided with a piezoelectric bimorph element  3024  for coming up against the left tragus, and the right-handed mobile telephone  3201  illustrated in  FIG. 56B  is provided with a piezoelectric bimorph element  3026  for coming up against the left tragus. Since usage is limited to a single side, for microphones and other outgoing-talk units, the left-handed mobile telephone  3101  of  FIG. 56A  is provided with an outgoing-talk unit (microphone)  1223  at the bottom of the left side surface, and the right-handed mobile telephone  3201  of  FIG. 56B  is provided with an outgoing-talk unit (microphone)  1123  at the bottom of the right side surface. The outgoing-talk units (microphones)  1123  or  1223  are similar to those of the twelfth embodiment or the thirteenth embodiment; during a videoconferencing function in which the large-screen display unit  205  is being observed, the outgoing-talk units (microphones)  1123  and  1223 , which serve as outgoing-talk units, are switched, and are able to pick up audio uttered by the user while the large-screen display unit  205  is being observed. 
     In the thirty-sixth embodiment of  FIG. 56 , as described above, the piezoelectric bimorph elements and/or microphones and other audio-related configurations relating to listening and speaking are integrated at the side surface of the mobile telephone; and the visual-related configuration of the large-screen display unit  205  and the like is integrated at the front surface of the mobile telephone. Therefore, as the side surface is used when the mobile telephone  3101  or  3201  is brought up against the face at the ear or the like and the front surface is used when the mobile telephone  3101  or  3201  is being watched with the eyes, the two surfaces of the mobile telephone  3101  or  3201  describing a 90° angle can be used separately, and the front surface of the mobile telephone  3101  or  3201  can be prevented from having the display surface  205  or the like fouled by the face. 
     In the thirty-sixth embodiment of  FIG. 56 , the side surface that is the opposite side at which the piezoelectric bimorph element  3024  or  3026  is not arranged is primarily used to hold the mobile telephone, and therefore, in a natural manner of holding with the hands, the side surface is covered with a material  3101   f  or  3201   f  that is rough to the touch, facilitating holding and also permitting a clear understanding of which side is brought up against the ear. The thirty-sixth embodiment, similarly with respect to the thirty-fifth embodiment, may also be configured such that the color of the vibration conductor for covering the piezoelectric bimorph element  3024  or  3026  is different from the color of the outer wall of the mobile telephone  3101  or  3201 . In a case in which the side surface of the opposite side in the thirty-sixth embodiment is covered with the material  3101   f  or  3201   f  that is rough to the touch, as described above, then the side surface of the side for listening to sound can be recognized, and accordingly there may be employed a design for implementing surface processing such that it is unknown whether the color of the vibration conductor has been rendered as the same color as the color of the outer wall of the mobile telephone  3101  or  3201 , and such that the boundary with the other side surface portion in the outer wall of the mobile telephone  3101  or  3201  is further unknown. The configuration of the thirty-fifth embodiment is otherwise shared with that of, for example, the twenty-sixth embodiment of  FIG. 41 , and therefore portions that are in common have been given like reference numerals, and a description thereof has been omitted. 
     However, the terms “right-handed” and “left-handed” in the thirty-sixth embodiment anticipate, for example, a state in which the side surface to which the piezoelectric bimorph element  3024  is provided comes up against the left ear cartilage when the side surface of the mobile telephone  3101  comes up against the ear, without the wrist being turned, directly out of the state in which the mobile telephone  3101  of  FIG. 56A  is held with the left hand and the display surface  205  is viewed. However, the user&#39;s method of use is discretionary; when the wrist is rotated 180° to turn the mobile telephone  3101  of  FIG. 56A  over when the mobile telephone  3101  is held in the right hand and brought up against the ear, the side surface of the side to which the piezoelectric bimorph element  3024  is provided can be brought up against the right ear cartilage. Accordingly, the terms “right-handed” and “left-handed” are merely provisional; the user is capable of purchasing either one and unrestrictedly selecting how to use same. The mobile telephone  3101  of  FIG. 56A  can accordingly be identified as being “right-handed” for a user who turns the wrist for use in the manner described above. 
     Thirty-Seventh Embodiment 
       FIG. 57  is a transparent perspective view relating to a thirty-seventh embodiment according to an aspect of the present invention, and is configured as a mobile telephone  3301 . The thirty-seventh embodiment of  FIG. 57  has many portions in common with the modification example of the tenth embodiment in  FIG. 40 ; therefore, portions in common have been given like reference numerals, and a description thereof has been omitted. A point of difference in the thirty-seventh embodiment from the modification example of the tenth embodiment lies in that the piezoelectric bimorph element  2525  is covered with a cartilage conduction output unit  3363 , in which not only the front surface but also the upper side and the front, rear, left, and right sides at the top edge of the mobile telephone  3301  are formed of a material having an acoustic impedance approximating that of ear cartilage. This cartilage conduction output unit  3363 , similarly with respect to the cartilage conduction output unit  963  in the tenth embodiment or in the modification example thereof, is formed using, for example, a silicone rubber; a mixture of a silicone rubber and a butadiene rubber; a natural rubber; or a material having a structure formed using these varieties of rubber in which air bubbles are sealed. 
     According to the configuration of the thirty-seventh embodiment, cartilage conduction can be obtained by any site anywhere on the top of the mobile telephone  3301  coming up against ear cartilage; therefore, sound can be listened to at an optimal volume merely by bringing the top part of the mobile telephone  3301  up against the ear, regardless of the location thereon. 
     The various features of each of the embodiments described above are not to be restricted to individual respective embodiments; they can be substituted or combined with other appropriate embodiments. 
     Thirty-Eighth Embodiment 
       FIG. 58  is a cross-sectional block diagram relating to a thirty-eighth embodiment according to an aspect of the present invention, and is configured as a mobile telephone  3401 . The thirty-eighth embodiment of  FIG. 58  shares many portions with the twenty-sixth embodiment or the twenty-seventh embodiment, and therefore portions that are in common have been given the same reference numerals as in  FIG. 42  and a description thereof has been omitted. A point of difference in the thirty-eighth embodiment from the twenty-sixth embodiment or from the twenty-seventh embodiment lies in it being configured such that the cartilage conduction vibration source  2525 , which is constituted of a piezoelectric bimorph element, is anchored to a chassis structure  3426  of the mobile telephone  3401 , and the vibration of the cartilage conduction vibration source  2525  is transmitted to the entire surface of the mobile telephone  3401 . In anchoring the piezoelectric bimorph element constituting the cartilage conduction vibration source  2525 , to actively transmit the vibration thereof, the gap  2504  such as in  FIG. 44B  is not provided, but rather there is a close bond to the chassis structure  3426 , and the vibration in the primary vibration direction (the Y-Y′ direction) is likely to be transmitted to the chassis structure  3426 . The entire surface of the mobile telephone  3401  thereby acts as a vibration conductor, and cartilage conduction can be obtained regardless of what location on the surface of the mobile telephone  3401  is brought up against the ear cartilage. 
     Because the thirty-eighth embodiment has the aforementioned configuration, in a case in which a large portion of the surface area of the front surface or the back surface of the mobile telephone  3401  is brought up against the entire cartilage of the ear, similarly with respect to the fifth to ninth embodiments, the vibration of the cartilage conduction vibration source  2525  is transmitted to the ear cartilage over a broad contacted surface area of the surface of the mobile telephone  3401  via the chassis structure  3426 . Air conduction sound that is generated by the vibration of the surface of the mobile telephone  3401  is also transmitted from the external auditory meatus to the tympanic membrane. Sound source information from the cartilage conduction vibration source  2525  can thereby be heard as a loud sound. The surface of the mobile telephone  3401  that is brought up against the ear assumes a form such that the external auditory meatus is obstructed, and therefore environment noise can be blocked. Increasing the force pushing the mobile telephone  3401  against the ear furthermore gives the result of substantially completely obstructing the external auditory meatus, and sound source information from the cartilage conduction vibration source  2525  can be heard as an even louder sound due to the earplug bone conduction effect. 
     In a case in which the side surface of the thirty-eighth embodiment is brought up against the ear cartilage, then the front surface of the mobile telephone to which the display surface and the like are provided can be prevented from being fouled by contact with the face, similarly with respect to the eleventh to fourteenth embodiments, the thirtieth embodiment, the thirty-first embodiment, the modification example of the thirty-third embodiment, and the thirty-fourth to thirty-sixth embodiments. Furthermore, in a case in which the upper edge corner of the thirty-eighth embodiment is brought up against the ear cartilage, contact with the tragus is readily achieved, and pushing on the tragus to obstruct the external auditory meatus can readily obtain the earplug bone conduction effect, similarly with respect to the first to fourth embodiments, the tenth embodiment and the modification example thereof, the twenty-sixth to twenty-ninth embodiments, and the thirty-third embodiment. The thirty-seventh embodiment of  FIG. 57  is configured such that cartilage conduction can be obtained by any site anywhere on the top of the mobile telephone  3301  being brought up against ear cartilage, but the thirty-eighth embodiment of  FIG. 58  expands on this feature; it is possible to listen to sound at an optimal volume merely by bringing the upper part of the mobile telephone  3401  up against the ear, at anywhere on the surface of the mobile telephone  3401 , regardless of the place. 
     In the thirty-eighth embodiment of  FIG. 58 , the cartilage conduction vibration source  2525  is anchored to the chassis structure  3426  such that the primary vibration direction of the piezoelectric bimorph element (the Y-Y′ direction) assumes an orientation orthogonal to that of a GUI display unit  3405  (conceptualized in the block diagram in  FIG. 58 , but is the large-screen display unit  205  having a touch panel function, when calling on the perspective view of  FIG. 41 , which relates to the twenty-sixth embodiment) (A cross-section of the anchoring is not illustrated in  FIG. 58 , but the manner of the anchoring will be described later). A large portion of the surface area of the front surface or the rear surface of the mobile telephone  3401 , to which the GUI display unit  3405  is provided, thereby vibrates efficiently. There is comparatively less energy in the non-vibration direction of the piezoelectric bimorph element (the X-X′ direction), due to the anchoring of the cartilage conduction vibration source  2525 , but because vibration does occur, sound can be listened to by cartilage conduction whenever a side surface of the mobile telephone  3401  is brought up against the ear cartilage. It shall be noted that the GUI display unit  3405  of  FIG. 58  is illustrated as a consolidation of the large-screen display unit  205  of  FIG. 42 , the display driver  41 , and the touch panel driver  2470 . 
     In the embodiment of  FIG. 58 , similarly with respect to the twenty-seventh embodiment, a function is selected by a motion sensor for the contactless detection of the motion of the finger in the vicinity of the GUI display unit  3405 , and an impact detection function of the piezoelectric bimorph element constituting the cartilage conduction vibration source  2525  is utilized as an impact sensor for detecting the touch of a finger for determining the selected function. The impact sensor  3442  illustrated in  FIG. 58  has a function similar to that of the pressure sensor  242  illustrated in  FIG. 9 , and extracts an impact detection signal of the piezoelectric bimorph element. The aforementioned arrangement of the primary vibration direction of the piezoelectric bimorph element (the Y-Y′ direction) to be oriented orthogonally with respect to that of the GUI display unit  3405  is suited for detecting a touch from the front surface or the back surface of the mobile telephone  3401 . The embodiment of  FIG. 58 , similarly with respect to the twenty-seventh embodiment, has the cartilage conduction vibration source  2525  serve a dual purpose as a low frequency output element for touch sensation feedback, but the aforementioned arrangement of the primary vibration direction of the piezoelectric bimorph element (the Y-Y′ direction) is suited for efficiently transmitting feedback vibration to a finger for a touch from the front surface or back surface of the mobile telephone  3401 . The embodiment of  FIG. 58 , similarly with respect to the description in the twenty-sixth embodiment, has the cartilage conduction vibration source  2525  serve a dual purpose as a vibration source of a vibrator for providing a noiseless notification of an incoming call to the mobile telephone  3401 . 
     The embodiment of  FIG. 58 , further similarly with respect to the fourth embodiment and similarly with respect to the twenty-seventh embodiment, is configured such that a horizontal stationary state is detected by the acceleration sensor  49 , and when this is true, the cartilage conduction vibration source  2525  is prohibited from vibrating. The potential generation of vibration noise with a desk due to the output of the other party&#39;s voice can thereby be prevented in a case in which the mobile telephone  3401  is placed on a desk or the like during a call. It is also appropriate to activate the aforementioned GUI operation or incoming call vibrator function in a case in which the mobile telephone  3401  is placed on a desk or the like, and thereof in such a case, the configuration is such that the cartilage conduction vibration source  2525  is not prohibited from vibrating whenever the horizontal stationary state is detected by the acceleration sensor  49 . A more detailed description of this point will be provided later as a function of the controller  3439 . 
     To configure the embodiment of  FIG. 58  such that the chassis structure  3426  of the mobile telephone  3401  is actively made to vibrate, there is the possibility that such vibration will be transmitted to the microphone  223  and result in the Larsen effect. As a countermeasure thereof, in order to block acoustic conduction between the chassis structure  3426  and microphone  223  of the mobile telephone  3401 , an insulation ring unit  3465  having an acoustic impedance different from that of the chassis structure  3426  is provided in between the two. A countermeasure for preventing the Larsen effect in a circuit-like manner is achieved using a signal conduction pathway from the outgoing-talk-processing unit  222  to the incoming-talk-processing unit  212  in the telephone function unit  45 . 
       FIG. 59  is a back surface transparent view and cross-sectional view illustrating the manner in which the cartilage conduction vibration source  2525  is anchored to the chassis structure  3426  of the mobile telephone  3401  in the thirty-eighth embodiment of  FIG. 58 .  FIG. 59A  is a back surface perspective view illustrating a part of the top end side of the mobile telephone  3401  of the thirty-eighth embodiment, and  FIG. 59B  is a cross-sectional view illustrating the B-B cross-section of  FIG. 59A .  FIG. 59C  is a transparent perspective view in which a part of the top end side in a modification example of the thirty-eighth embodiment is viewed from the side surface of the opposite side. The configuration of the piezoelectric bimorph element is similar to that in  FIG. 44B , and therefore portions that are in common have been given like reference numerals. 
     As is clear from  FIG. 59A , in the thirty-eighth embodiment, the metal sheet  2597  of the piezoelectric bimorph element constituting the cartilage conduction vibration source  2525  is arranged so as to be parallel to the front surface of the mobile telephone  3401 ; as a result thereof, the cartilage conduction vibration source  2525  is anchored to the chassis structure  3426  such that the Y-Y′ direction, which is the primary vibration direction, is oriented to be orthogonal to the GUI display unit  3405 . As is clear from  FIG. 59B , the piezoelectric bimorph element constituting the cartilage conduction vibration source  2525  is tightly secured on the inner side of the chassis structure  3426  without any gap, the configuration being such that the vibration in the primary vibration direction (the Y-Y′ direction) is prone to being transmitted to the surface of the chassis structure  3426 . 
     In a modification example of the thirty-eighth embodiment in  FIG. 59C , the metal sheet  2597  of the piezoelectric bimorph element constituting the cartilage conduction vibration source  2525  is arranged so as to be in parallel with the side surface of the mobile telephone  3401 ; as a result thereof, the cartilage conduction vibration source  2525  is anchored to the chassis structure  3426  such that the Y-Y′ direction, which is the primary vibration direction, is oriented to be orthogonal to the side surface of the mobile telephone  3401 . Cartilage conduction can thereby be efficiently obtained when the side surface of the mobile telephone  3401  is brought up against the ear. There is comparatively less energy in the non-vibration direction of the piezoelectric bimorph element (the X-X′ direction), due to the anchoring of the cartilage conduction vibration source  2525 , but because vibration does occur, sound can be listened to by cartilage conduction whenever the front surface or back surface of the mobile telephone  3401  is brought up against the ear cartilage. In the modification example of the thirty-eighth embodiment in  FIG. 59C  as well, similarly with respect to  FIG. 59B , the piezoelectric bimorph element constituting the cartilage conduction vibration source  2525  is tightly secured to the inner side of the chassis structure  3426 , without any gap, the configuration being such that the vibration in the primary vibration direction (the Y-Y′ direction) is likely to be transmitted to the surface of the chassis structure  3426 . 
       FIG. 60  is a flow chart of the operation of a controller  3439  in the thirty-eighth embodiment of  FIG. 58 . The flow of  FIG. 60  illustrates an abstraction of the operation that focuses on related functions, in order to primarily provide a description of the control of the cartilage conduction vibration source  2525 ; the controller  3439  also contains typical functions of mobile telephones and other operations not represented in the flow of  FIG. 60 . The flow of  FIG. 60  begins when a main power source of the mobile telephone  3401  is turned on; in step S 262  an initial startup and a check of each unit function are performed and a screen display on the GUI display unit  3405  is started. Subsequently, in step S 264 , the function of the cartilage conduction vibration source  2525  is turned off and the flow moves on to step S 266 . 
     In step S 266 , there is performed a check for whether or not the mobile telephone  3401  is in the middle of a call. When the line is newly connected, a call is in progress and therefore the flow proceeds to step S 268 , in which the outgoing-talk-processing unit  222  and the incoming-talk-processing unit  212  are turned on; the flow then moves on to step S 270 . In a case in which the line is connected and a call has already been in progress, the flow proceeds from step S 266  to step S 268 ; in such a case, the outgoing-talk-processing unit  222  and the incoming-talk-processing unit  212  are continuously kept on and the flow moves on to step S 270 . 
     In step S 270 , there is performed a check for whether or not a horizontal stationary state has been detected by the acceleration sensor  49 ; when there is no horizontal stationary state, the flow moves on to step S 272 , which turns on the cartilage conduction vibration source  2525 , whereupon the flow moves on to step S 274 . However, when the cartilage conduction vibration source  2525  is already on, the on state continues. On the other hand, when there is a detection of a horizontal stationary state in step S 270 , the flow proceeds to step S 276 , which checks for whether the outgoing-talk-processing unit  222  and the incoming-talk-processing unit  212  are in an on state. Then, in such a case, since an on state is in effect, the flow proceeds to step S 278 . The cartilage conduction vibration source  2525  is turned off and the flow moves on to step S 274 . When the cartilage conduction vibration source  2525  is already off, the off state continues. In step S 274 , there is performed a check for whether or not a call is in progress; when a call is in progress, the flow returns to step S 270 . Thereafter, as long as a call is in progress, steps S 270  to S 278  are repeated. Thus, when the mobile telephone  3401  is temporarily placed on a desk or the like during a call, then whenever the voice of the other party is received, the vibration of the cartilage conduction vibration source  2525  is interrupted therebetween, and the generation of uncomfortable noise from vibration with the desk is prevented. As shall be apparent, when a horizontal stationary state is not detected in step S 270 , the cartilage conduction vibration source  2525  is turned on in step S 272  and the call is reactivated. 
     On the other hand, when it is detected in step S 266  that a state in which a call is not in progress is in effect or that a call is not in progress due to the termination of the call, the flow proceeds to step S 280 , the outgoing-talk-processing unit  222  and the incoming-talk-processing unit  212  are turned off, and the flow moves on to step S 282 . However, when the outgoing-talk-processing unit  222  and the incoming-talk-processing unit  212  are off, the off state continues and the flow moves on to step S 282 . In step S 282 , there is performed a check for whether there is an incoming call; when there is no incoming call, the flow moves on to step S 284 , in which there is performed a check for whether or not a GUI mode is in effect. Then, when a GUI mode is in effect, the flow proceeds to step S 286 , in which there is impact sensor detection processing; then, in step S 288 , there is touch sensation feedback processing, and the flow moves on to step S 290 . The flow moves directly on to step S 290  when there is no operation at all, and when there is an operation, Steps S 286  and S 288  perform processing for implementing impact sensor detection and touch sensation feedback, which are based on the operation. 
     In step S 290 , the low frequency source  2466  is turned on and prepared for the input of a touch sensation feedback signal or the like. The flow then proceeds to step S 270 , in which there is a check for the presence or absence of a detection of a horizontal stationary state. Then, when there is no horizontal stationary state, the flow moves on to step S 272 , in which the cartilage conduction vibration source  2525  is turned on and prepared for the input of a touch sensation feedback signal or the like. The flow moves on to step S 276  when a horizontal stationary state is detected in step S 270 , but in such a case, the outgoing-talk-processing unit  222  and the incoming-talk-processing unit  212  are not on, and therefore the flow still moves on to step S 272 , and the cartilage conduction vibration source  2525  is turned on. Thus, the cartilage conduction vibration source  2525  is turned on when the low frequency source  2466  is turned on, even when a horizontal stationary state is detected. When the cartilage conduction vibration source  2525  is turned on, the impact sensor function thereof is also maintained. 
     On the other hand, when an incoming call is detected in step S 282 , the flow proceeds to step S 292 , a “vibe” signal for providing a notification of the incoming call is outputted; the flow then moves on to step S 290 . In such a case as well, the low frequency source  2466  is turned on in step S 290  and the cartilage conduction vibration source  2525  is turned on in step S 272 , but the flow also moves on to step S 272  even when the horizontal stationary state is detected in step S 270 , and the fact that the cartilage conduction unit  2525  is turned on is a point of similarity with the case in which the GUI mode is in effect. 
     When it is detected in step S 274  that no call is in progress, the flow moves on to step S 296 , in which there is performed a check for whether the primary power supply has been turned off. Once the low frequency source  2466  is turned on in step S 290 , no call is in progress even when step S 274  is reached, and therefore the flow moves on to step S 296 . When there is no detection made in step S 284  that a GUI mode is in effect, the flow proceeds to step S 294 , the low frequency source  2466  is turned off, and the flow then arrives at step  296 . When it is detected in step S 296  that the primary power supply has been turned off, the flow is terminated. On the other hand, in a case in which there is no detection made in step S 296  that the primary power supply is off, the flow returns to step S 266 , following which steps S 266  to S 296  are repeated and various situational changes are supported. 
     The various features of each of the embodiments described above are not to be limited to the above embodiments; rather, wherever it is possible to benefit from the feature of an embodiment, same can also be implemented in other aspects. The various features of each of the embodiments described above are not to be restricted to individual respective embodiments, but rather can be substituted or combined with other appropriate embodiments. For example, regarding the control of the cartilage conduction vibration source  2525  relating to being horizontally stationary, the thirty-eighth embodiment described above can be configured such that, in a case in which there is check for whether or not a videoconferencing function mode is in effect and the mode is in effect, the videoconferencing function speaker is turned on in tandem with the cartilage conduction vibration source  2525  being turned off in step S 278  of  FIG. 60 . 
     The mode in the thirty-eighth embodiment in which the cartilage conduction vibration source  2525  is supported by the chassis structure  3426  of the mobile telephone  3401  is not to be limited to a rigid, direct anchoring such as in the thirty-eighth embodiment. For example, the rigid support may be indirect, via another holding structure, provided that it remains possible to transmit vibration. The support is also not necessarily limited to being rigid; rather, holding may be achieved via an elastic body, provided that the acoustic impedance is approximated and vibration is transmitted to the chassis surface. 
     Thirty-Ninth Embodiment 
       FIG. 61  is a cross-sectional view relating to a thirty-ninth embodiment according to an aspect of the present invention as well as to various modification examples thereof, and is configured as mobile telephones  3501   a  to  3501   d . The thirty-ninth embodiment is consistent with, for example, the thirty-eighth embodiment illustrated in  FIGS. 58 to 60 , except for the arrangement of the cartilage conduction vibration source  2525 , which is constituted of a piezoelectric bimorph element (and which hereinafter is described using the example of the piezoelectric bimorph element  2525 ). Therefore, the diagram does not contain those portions for which no description is needed, and of the illustrated portions, shared portions have been given like reference numerals, a description thereof having been omitted unless there is a particular need. 
       FIG. 61A  relates to the thirty-ninth embodiment, and is a cross-sectional view in which the mobile telephone  3501   a  is viewed from above as being cut in a plane that is perpendicular to the side surface thereof and to the display surface of the GUI display unit  3405 . As is clear from the diagram, the piezoelectric bimorph element  2525  is arranged along one side surface of the mobile telephone  3501   a  as in the modification example of the thirty-eighth embodiment in  FIG. 59C . However, in the thirty-ninth embodiment of  FIG. 61 , the primary vibration direction of the piezoelectric bimorph element  2525  (the Y-Y′ direction) is not perpendicular to the side surface, but rather is supported so as to incline relative to the side surface. More specifically, the side surface of the thirty-ninth embodiment is provided with an inclined side surface  3507   a  to which four beveled side surface ridge portions are provided; the piezoelectric bimorph element  2525  has a primary vibration surface (the “outer surface of the piezoelectric bimorph element  2525  that is in parallel with the metal sheet  2597 ” is defined as the “primary vibration surface”) that is bonded to one inner side of the inclined side surface  3507   a  for support. The primary vibration direction (which is the Y-Y′ direction, and is the direction perpendicular to the primary vibration surface) of the piezoelectric bimorph element  2525  thereby becomes perpendicular to the inclined side surface  3507   a.    
     Due to such a structure, the user of the mobile telephone  3501   a  can prevent the display surface of the GUI display unit  3405  from being fouled by contact with the cheek, and can also readily bring the inclined side surface  3507   a  of the mobile telephone  3501   a  up against the ear cartilage. The configuration, which integrates the audio-related configuration into the side surface of the mobile telephone and integrates the visual-related configuration into the front surface of the mobile telephone, as has already been described in the other embodiments, is significant in that the uses of the two surfaces of the mobile telephone  3501   a  can be divided such that the side surface is utilized when the mobile telephone  3501   a  is brought up against the ear or other part of the face and the front surface is utilized when the mobile telephone is watched with the eyes, and in that the front surface of the mobile telephone  3501   a  can be prevented from having the display surface of the GUI display unit  3405  fouled by the face. However, rather than causing the side surface in its entirety to make perpendicular contact with the ear during the usage of the side surface, it is also possible to conceive of a usage state in which the mobile telephone  3501   a  is caused to make contact with the ear such that the display surface of the GUI display unit  3405  is turned slightly toward the face. The thirty-ninth embodiment of  FIG. 61A  is configured in anticipation of such usage. 
     As mentioned above, the thirty-ninth embodiment of  FIG. 61A  has the direction of arrow  25 A serving as the primary vibration direction in the inclined side surface  3507   a , in which the piezoelectric bimorph element  2525  is bonded to the inner side, but since the primary vibration direction is inclined, there is created a vibration component having a direction that is perpendicular to the display surface of the GUI display unit  3405 , illustrated by arrow  25 B. A side surface vibration component illustrated by arrow  25 C is also created. Sound can thereby be listened to even in a case in which the front surface of the mobile telephone  3501   a  (the display surface of the GUI display unit  3405 ) or the back surface thereof, and, furthermore, either of the two side surfaces of the mobile telephone  3501   a , is brought up against the ear cartilage. Any position of the mobile telephone  3501   a  can accordingly be discretionarily used, taking the direction of arrow  25 A as the best direction. In the thirty-ninth embodiment of  FIG. 61A , the inclined side surface  3507   a  assumes an incline that is close to the display surface of the GUI display unit  3405 ; therefore, the vibration component of the direction illustrated by arrow  25 B is greater than the vibration component of the direction illustrated by arrow  25 C. 
       FIG. 61B  is a first modification example of the thirty-ninth embodiment; the mobile telephone  3501   b  is configured such that the incline of the inclined side surface  3507   b  is substantially 45° relative to the display surface of the GUI display unit  3405 , whereby the vibration component of the direction illustrated by arrow  25 B becomes substantially even with the vibration component of the direction illustrated by arrow  25 C. By contrast, FIG.  61 C is a second modification example of the thirty-ninth embodiment. The mobile telephone  3501   c  is configured such that the inclined side surface  3507   c  assumes an incline that is close to the side surface, whereby the vibration component of the direction illustrated by arrow  25 C becomes greater than the vibration component of the direction illustrated by arrow  25 B. 
       FIGS. 61A to 61C  are extreme illustrations for describing a broad overview of the inclines, but the extreme directivity in the vibration of the piezoelectric bimorph element  2525  is not maintained after having been transmitted to the mobile telephones  3501   a  to  3501   c ; therefore, subtle changes in the orientation of the primary vibration direction of the piezoelectric bimorph element  2525  provided to the side surface of the mobile telephone will not incur perceptible changes to the vibration components. However, there is great significance in adjusting the arrangement direction of the piezoelectric bimorph element  2525  as in the thirty-ninth embodiment and the modification examples thereof, when the best position of the contact with the ear cartilage is considered. For example, in a case as in  FIGS. 61A to 61C  in which a planar inclined side surface is provided, it is of practical utility for the front surface of the mobile telephones  3501   a  to  3501   c  (the display surface of the GUI display unit  3405 ) and the inclined side surfaces  3507   a  to  3507   c  to be imparted with an incline of between approximately 30 to 60°. 
       FIG. 61D  is a third modification example of the thirty-ninth embodiment; the side surface of a mobile telephone  3501   d  serves as a semicylindrical surface  3507   d . The configuration is such that support is provided by pushing on the inner side of the semicylindrical surface  3507   d  such that the primary vibration direction of arrow  25 A assumes a substantially 45° angle relative to the display surface of the GUI display unit  3405 , and the vibration component of the direction illustrated by arrow  25 B becomes substantially equivalent to the vibration component of the direction illustrated by arrow  25 C. The user is thereby able to bring up against the ear cartilage any desired place across the front surface of the mobile telephone  3501   d  (the display surface of the GUI display unit  3405 ) or across the back surface thereof, from the semicylindrical surface  3507   d  of the side surface. In the third modification example of the thirty-ninth embodiment of  FIG. 61D , the primary vibration direction of arrow  25 A is not limited to a case of having a substantially 45° angle relative to the display surface of the GUI display unit  3405 , and can be established in various inclines such as in  FIGS. 61A to 61C . Another possible configuration is one in which it is possible to adjust the incline of holding and in which a service for altering the incline in accordance with the user&#39;s desire can be provided. 
     Fortieth Embodiment 
       FIG. 62  represents cross-sectional views and a transparent perspective view of the elements relating to a fortieth embodiment according to an aspect of the present invention as well as to various modification examples thereof, and is configured as mobile telephones  3601   a  to  3601   c . The fortieth embodiment is also consistent with the thirty-eighth embodiment illustrated in  FIGS. 58 to 60 , except for the arrangement of the cartilage conduction vibration source  2525 , which is constituted of a piezoelectric bimorph element (and which hereinafter is described using the example of the piezoelectric bimorph element  2525 ). Therefore, the diagram does not contain those portions for which no description is needed, and of the illustrated portions, shared portions have been given like reference numerals, a description thereof having been omitted unless there is a particular need. 
       FIG. 62A  relates to the fortieth embodiment, and is a cross-sectional view in which the mobile telephone  3601   a  is viewed from above as being cut in a plane that is perpendicular to a side surface  3607  thereof and to the display surface of the GUI display unit  3405 . As is clear from the diagram, the piezoelectric bimorph element  2525  is arranged along one side surface  3607  of the mobile telephone  3601   a  as in the modification example of the thirty-eighth embodiment in  FIG. 59C . However, in the fortieth embodiment of  FIG. 62 , similarly with respect to the thirty-ninth embodiment, the piezoelectric bimorph element  2525  has a primary vibration direction (the Y-Y′ direction) that is not perpendicular to the side surface, the piezoelectric bimorph element  2525  being supported so as to be inclined relative to the side surface  3607 . The fortieth embodiment is configured such that the vibrations from the primary vibration surfaces of the two sides of the piezoelectric bimorph element  2525  are respectively transmitted to the mutually orthogonal side surface  3607  and display surface of the GUI display unit  3405 . 
     More specifically, the chassis of the mobile telephone  3601   a  of the fortieth embodiment in  FIG. 62A  is provided with a first support structure  3600   a  that extends to the inner side from the side surface  3607 , and is bonded to one primary vibration surface of the piezoelectric bimorph element  2525 ; and is also provided with a second support structure  3600   b  that extends to the inner side from the chassis on the display surface of the GUI display unit  3405 , and is bonded to the other primary vibration surface of the piezoelectric bimorph element  2525 . The primary vibration in the direction illustrated by arrow  25 A is thereby broken down into the vibration component illustrated by arrow  25 D and the vibration component illustrated by arrow  25 E having a direction orthogonal thereto, each of which being respectively transmitted to the side surface  3607  and the chassis surface on the display surface of the GUI display unit  3405 . Thus, the vibration of the two primary vibration surfaces in the piezoelectric bimorph element  2525  is transmitted broken down into orthogonal directions of the mobile telephone  3601   a ; and the vibration of the piezoelectric bimorph element  2525  can be heard regardless of which portion of the front surface, the back surface, or the side surface of the mobile telephone  3601   a  is brought up against the ear cartilage. The fortieth embodiment in  FIG. 62A  is provided with the first support structure  3600   a  and the second support structure  3600   b  so as to sandwich the same portion of the piezoelectric bimorph element  2525  from two sides. 
     By contrast,  FIG. 62B  is a transparent perspective view in which the elements of the mobile telephone  3601   b  of a first modification example of the fortieth embodiment are viewed from within. As is clear from  FIG. 62B , in the first modification example of the fortieth embodiment, the first support structure  3600   a  and the second support structure  3600   b  are provided so as to be bonded to the mobile telephone  3601   b  in positions where the primary vibration surfaces facing the piezoelectric bimorph element  2525  mutually cross. The operation to bond to the piezoelectric bimorph element  2525  is thereby facilitated, the degree of freedom with which the piezoelectric bimorph element  2525  vibrates is less inhibited, and the vibration thereof can be efficiently transmitted to the chassis of the mobile telephone  3601   b.    
       FIG. 62C  is a cross-sectional view in which the mobile telephone  3601   c  of a second modification example of the fortieth embodiment is viewed from the side having been cut along a plane that is perpendicular to a side surface  3607   a  and the top surface. In the fortieth embodiment of  FIG. 62A , the primary vibration directions of the piezoelectric bimorph element  2525  are broken down into vibration components having directions perpendicular to the front surface and the side surfaces respectively, but in the second modification example of the fortieth embodiment in  FIG. 62C , the primary vibration directions of the piezoelectric bimorph element  2525  are broken down into vibration components having directions that are perpendicular to the front surface and the top surface respectively. 
     More specifically, as is clear from  FIG. 62C , the chassis of the mobile telephone  3601   c  in the second modification example of the fortieth embodiment is provided with a first support structure  3600   c  that extends to the inner side from the top surface, and is bonded to one primary vibration surface of the piezoelectric bimorph element  2525 . The chassis of the mobile telephone  3601   c  in the second modification example of the fortieth embodiment is also provided with a second support structure  3600   d  that extends to the inner side from the chassis on the display surface of the GUI display unit  3405 , and is bonded to the other primary vibration surface of the piezoelectric bimorph element  2525 . The primary vibration in the direction illustrated by arrow  25 A is thereby broken down into the vibration component illustrated by arrow  25 F and the vibration component illustrated by arrow  25 E having a direction orthogonal thereto, each being respectively transmitted to the top surface and the chassis surface on the display surface of the GUI display unit  3405 . Thus, the vibration of the two primary vibration surfaces in the piezoelectric bimorph element  2525  is transmitted broken down into orthogonal directions of the mobile telephone  3601   c ; the vibration of the piezoelectric bimorph element  2525  can be heard regardless of which portion of the front surface, the back surface, the top surface, or the bottom surface of the mobile telephone  3601   c  is brought up against the ear cartilage. The second modification example of the fortieth embodiment in  FIG. 62C  has a cross-sectional view of a form in which the first support structure  3600   c  and the second support structure  3600   d  are provided such that the same portion of the piezoelectric bimorph element  2525  is sandwiched from both sides, similarly with respect to  FIG. 62A ; however, the configuration may be such that, as in  FIG. 62B , crossing portions of the two surfaces of the piezoelectric bimorph element  2525  are respectively bonded. 
     The second modification example of the fortieth embodiment in  FIG. 62C  is not only suited for listening to sound by bringing the front surface or the rear surface of the mobile telephone  3601   c  alongside the ear cartilage, but is also appropriate for usage in which the top surface of the mobile telephone  3601   c  is brought up against the ear cartilage in such a form as to lightly push upward. This embodiment is also appropriate in that by such usage, not only is the display surface prevented from being fouled by contact with the face, but increasing the force pushing upward on the top surface obstructs the external auditory meatus with the tragus, and the earplug bone conduction effect is readily created. 
     Forty-First Embodiment 
       FIG. 63  is a cross-sectional view relating to a forty-first embodiment according to an aspect of the present invention, and is configured as a mobile telephone  3701 . The forty-first embodiment is also consistent with the thirty-eighth embodiment illustrated in  FIGS. 58 to 60 , except for the arrangement of the cartilage conduction vibration source  2525 , which is constituted of a piezoelectric bimorph element (and which hereinafter is described using the example of the piezoelectric bimorph element  2525 ); therefore, the diagram does not contain those portions for which no description is needed, and of the illustrated portions, shared portions have been given like reference numerals, a description thereof having been omitted unless there is a particular need. 
       FIG. 63A  is a cross-sectional view in which the mobile telephone  3701  of the forty-first embodiment is viewed from above as being cut in a plane that is perpendicular to a side surface  3707  thereof and to the display surface of the GUI display unit  3405 . As is clear from the diagram, the piezoelectric bimorph element  2525  is arranged along the top surface of the mobile telephone  3701  as in the thirty-eighth embodiment in  FIG. 59A . The primary vibration direction of the piezoelectric bimorph element  2525  (the Y-Y′ direction) is a direction that is perpendicular to the display surface of the GUI display unit  3405 . Specifically, the middle portion of the piezoelectric bimorph element  2525  is bonded to a support structure  3700   a  that extends to the inner side from the back surface of the mobile telephone  3701 , and the two end portions of the piezoelectric bimorph element  2525  are supported together as free ends in a state in which vibration is not hampered. As a result, the counteraction of the free vibration of the two end portions of the piezoelectric bimorph element  2525  as illustrated by arrow  25 G and arrow  25 H is transmitted to the chassis of the mobile telephone  3701  via the support structure  3700   a  from the middle portion of the piezoelectric bimorph element  2525 . 
       FIG. 63B  is a cross-sectional view in which the B-B cross-section of  FIG. 63A  is viewed from the side of the mobile telephone  3701 ; it can be understood that the piezoelectric bimorph element  2525  is supported by the support structure  3700   a  in which the piezoelectric bimorph element  2525  extends to the inner side from the back surface of the mobile telephone  3701 , and also that the piezoelectric bimorph element  2525  is arranged along the top surface of the mobile telephone  3701 . As shown in  FIG. 63 , the structure, in which a part of the primary vibration surface of the piezoelectric bimorph element  2525  is supported on the inner side of the chassis of the mobile telephone  3701  and a part of the primary vibration surface is permitted to unrestrictedly vibrate in an unsupported manner, is appropriate for efficiently transmitting the vibration of the piezoelectric bimorph element  2525  to the chassis of the mobile telephone without adding any substantive change to the acoustic properties thereof. The support at the middle of the piezoelectric bimorph element  2525  such as in the forty-first embodiment is also particularly appropriate in a case of a piezoelectric bimorph element having a terminal positioned at the middle of the element, as in the thirty-second embodiment illustrated in  FIG. 51 . 
       FIG. 64  illustrates various modification examples of the forty-first embodiment of  FIG. 63 , and, similarly with respect to  FIG. 63A , is a cross-sectional view in which the mobile telephone  3701  is viewed from above as being cut in a plane that is perpendicular to the side surface  3707  thereof and to the display surface of the GUI display unit  3405 . 
       FIG. 64A  is a first modification example of the forty-first embodiment, and is particularly suited to a case in which the terminal  2525   b  of the piezoelectric bimorph element  2525  is positioned at an end part of the element, the center of gravity is unbalanced, and the free vibration of the terminal  2525   b  illustrated by arrow  25 G is slightly confined by the electrode connection to the element, compared to the vibration of the entire free end illustrated by arrow  25 H. To compensate for the unbalancing, the first modification example of  FIG. 64A  shifts the position of the support structure  3701   b  to the left in the diagram compared to the support structure  3700   a  of the forty-first embodiment of  FIG. 63 . 
       FIG. 64B  is a second modification example of the forty-first embodiment; each of the two ends of the piezoelectric bimorph element is bonded to a pair of support structures  3700   c  and  3700   d  that extend to the inner side from the back surface of the mobile telephone  3701 . The vibration of the middle portion of the piezoelectric bimorph element illustrated by arrow  25 I is thereby freed, and the counteraction of this vibration is transmitted to the chassis of the mobile telephone  3701  via the support structures  3700   c  and  3700   d.    
       FIG. 64C  is a third modification example of the forty-first embodiment, the terminal  2525   b  being bonded to a support structure  3700   e  extending inward from the back surface of the mobile telephone  3701 , whereby the piezoelectric bimorph element  2525  is supported on a cantilever structure. The counteraction of the vibration of the free ends of the piezoelectric bimorph element  2525  illustrated by arrow  25 H is thereby transmitted to the chassis of the mobile telephone  3701  via the support structure  3700   e.    
       FIG. 64D  is a fourth modification example of the forty-first embodiment; the piezoelectric bimorph element  2525  is bonded to the inner side of the chassis of the back surface of the mobile telephone  3701  interposed by a two-sided bonding sheet  3700   f  comprising an elastic body. The two-sided bonding sheet  3700   f  comprising an elastic body is made using an elastic body that has conductivity from the piezoelectric bimorph element  2525  to the chassis (a silicone rubber; a mixture of a silicone rubber and a butadiene rubber; a natural rubber; a structure formed using these varieties of rubber in which air bubbles are sealed; or the like) or the like. Due to such elastic bonding, each portion of the piezoelectric bimorph element  2525  obtains a degree of free vibration illustrated by arrows  25 G,  25 H, and  25 I, and the vibration thereof is transmitted to the chassis of the mobile telephone  3701  via the two-sided bonding sheet  3700   f.    
     The various features of each of the embodiments described above are not to be restricted to individual respective embodiments, but rather can be substituted or combined with other appropriate embodiments. For example, the support structure of the forty-first embodiment in  FIGS. 63 and 64 , in which consideration is given to the free vibration of the piezoelectric bimorph element  2525 , can also be applied to the case of the inclined holding of the piezoelectric bimorph element  2525  in the thirty-ninth embodiment of  FIG. 61  and the fortieth embodiment of  FIG. 62 . Specifically, the support structure in  FIG. 62B  has a point in common in the sense that the two ends of the piezoelectric bimorph element  2525  are supported and the middle part is freed. There is no limitation to this example; for example, rather than bonding the entire vibration plane to the inner side of the inclined side surface, it is also possible in the thirty-ninth embodiment of  FIG. 61  and the modification examples thereof to provide a projection unit analogous to the support structure  3700   a  of  FIG. 63A  to the inclined side surface, only the middle portion of the piezoelectric bimorph element  2525  being bonded thereto to make the two end parts thereof into free ends. Alternatively, it is also possible in the thirty-ninth embodiment of  FIG. 61  and the modification examples thereof to interpose an elastic body, as in the fourth modification example of the forty-first embodiment in  FIG. 64D , when the piezoelectric bimorph element  2525  is bonded. 
     The implementation of the features of the present invention described above is not to be limited to the aspects in the above embodiments; the invention can be implemented using other aspects as well, wherever it is possible to benefit from the advantages thereof. For example, although the thirty-ninth embodiment of  FIG. 61  has been described with the piezoelectric bimorph element  2525  being bonded to and supported by the inner side of the inclined side surface inside the mobile telephone, the specific structure for support is not to be limited thereto. For example, referring to the thirty-first embodiment of  FIG. 49 , the structure may be one in which a groove may be provided to the outer side of the inclined side surface and the piezoelectric bimorph element  2525  is fitted into this groove from the outer side. 
     Forty-Second Embodiment 
       FIG. 65  is a cross-sectional view relating to a forty-second embodiment according to an aspect of the present invention, and is configured as a mobile telephone  3801 . The forty-second embodiment is consistent with the thirty-eighth embodiment illustrated in  FIGS. 58 to 60 , except for the arrangement of the cartilage conduction vibration source  2525 , which is constituted of a piezoelectric bimorph element (and which hereinafter is described using the example of the piezoelectric bimorph element  2525 ), and except for the holding structure thereof; therefore, the diagram does not contain those portions for which no description is needed, and of the illustrated portions, shared portions have been given like reference numerals, a description thereof having been omitted unless there is a particular need. 
       FIG. 65A  is a cross-sectional view in which the mobile telephone  3801  of the forty-second embodiment is viewed from above as being cut in a plane that is perpendicular to a side surface  3807  thereof and to the display surface of the GUI display unit  3405 .  FIG. 65B  is a cross-sectional view in which the B-B cross-section of  FIG. 65A  is viewed from the side of the mobile telephone  3801 . As is clear from  FIG. 65A , the piezoelectric element  2525  is arranged along the top surface of the mobile telephone  3801 , similarly with respect to the thirty-eighth embodiment in  FIG. 59A , the forty-first embodiment in  FIG. 63 , or the like. The primary vibration direction of the piezoelectric bimorph element  2525  is the direction perpendicular to the display surface of the GUI display unit  3405 , as illustrated by arrow  25 G. Thus, the forty-second embodiment of  FIG. 65 , in essence, has one side of the piezoelectric bimorph element  2525  supported by a cantilever structure, similarly with respect to the modification example of the forty-first embodiment illustrated in  FIG. 64C . The counteraction of the vibration of the free end of the piezoelectric bimorph element  2525  illustrated by arrow  25 G is thereby transmitted to the chassis of the mobile telephone  3801 . 
     A point of difference in the forty-second embodiment of  FIG. 65  from the modification example of the forty-first embodiment illustrated in  FIG. 64C  lies in it being configured such that an upper part corner  3824 , which is a site on the chassis of the mobile telephone  3801  that is appropriate for being brought up against the tragus or other ear cartilage, is made to vibrate particularly efficiently, and also such that it is possible for the structure of the upper part corner  3824 , which is also a site that is likely to bear the direct application of impact when a drop or the like occurs, to avoid having a structure that is low in terms of collision resistance. Specifically, as illustrated in  FIGS. 65A and 65B , one end of the piezoelectric bimorph element  2525  is inserted and held in a hole of a support structure  3800   a  extending inward from the side surface  3807  and the top surface  3807   a  of the mobile telephone  3801 , as a holding end  2525   c . The holding end  2525   c  is an end to which the terminal  2525   b  is not provided. Thus, making the one end to which the terminal  2525   b  is not provided into a holding end  2525   c  permits the support position to be brought closer to the vicinity of the upper part corner  3824 . By contrast, the other end to which the terminal  2525   b  is provided is made to vibrate as a free end. The terminal  2525   b  is connected to a circuit  3836  and flexible wiring  3836   a  installed in the chassis; the free vibration of the other end to which the terminal  2525   b  is provided will not be substantively hampered. The circuit  3836  comprises an amp or the like for boosting the drive voltage of the piezoelectric bimorph element  2525 . 
     Due to the configuration described above, the counteraction of the free vibration of the other end of the piezoelectric bimorph element  2525  illustrated by arrow  25 G is transmitted to the chassis of the mobile telephone  3801  via the support structure  3800   a  from the holding end  2525   c  of the piezoelectric bimorph element  2525 . At this time, the support structure  3800   a , as described above, is configured so as to extend to the inner side from the side surface  3807  and the top surface  3807   a  of the mobile telephone  3801  at the upper part corner  3824  of the chassis; therefore, the counteraction of the free vibration of the other end of the piezoelectric bimorph element  2525  is efficiently transmitted to the upper part corner  3824 . As described above, the piezoelectric bimorph element  2525  is held in the inner side of the chassis of the mobile telephone  3801 , and therefore the structure of the upper part corner  3824 , which is also a site that is prone to the direct application of an impact, will not have low resistance to collision. 
       FIG. 65C  is a first modification example of the forty-second embodiment; the piezoelectric bimorph element  2525  is held such that the primary vibration direction becomes the direction perpendicular to the top surface  3807   a , as illustrated by arrow  25 J. The structure is otherwise similar to that of the forty-second embodiment of  FIGS. 65A and 65B , and therefore a description thereof has been omitted. The first modification example in  FIG. 65C  has a large vibration component in the direction perpendicular to the top surface  3807   a , and is therefore suited for usage in which the top surface side of the upper part corner  3824  of the mobile telephone  3801  is brought up against the ear cartilage in such a form as to push lightly upward. This embodiment is also appropriate in that, due to such use, not only can the display surface of the GUI display unit  3405  be prevented from being fouled by contact with the face, but also increasing the force pushing upward on the top surface  3807   a  obstructs the external auditory meatus with the tragus, and the earplug bone conduction effect is readily created. The first modification example in  FIG. 65C , similarly with respect to the forty-second embodiment of  FIGS. 65A and 65B , can be used upon the display surface side of the upper part corner  3824  of the mobile telephone  3801  being brought up against the ear cartilage. In such a case as well, increasing the force with which the display surface is pushed against the ear cartilage makes it possible for the external auditory meatus to be obstructed with the tragus, and the earplug bone conduction effect can readily be created. 
       FIG. 65D  is a second modification example of the forty-second embodiment. The primary vibration direction is inclined 45° relative to the top surface  3807   a , as illustrated by arrow  25 K. The vibration components are thereby broken down into the direction that is perpendicular to the top surface  3807   a  and the direction that is perpendicular to the display surface of the GUI display unit  3405 , which is orthogonal thereto, and comparable cartilage conduction can be obtained regardless of the direction from which the upper part corner  3824  comes into contact with the ear cartilage. 
     Forty-Third Embodiment 
       FIG. 66  is a cross-sectional view relating to a forty-third embodiment according to an aspect of the present invention, and is configured as a mobile telephone  3901 . The forty-third embodiment is consistent with the thirty-eighth embodiment illustrated in  FIGS. 58 to 60 , except for the arrangement of the cartilage conduction vibration source  2525 , which is constituted of a piezoelectric bimorph element (and which hereinafter is described using the example of the piezoelectric bimorph element  2525 ), and except for the holding structure thereof. Therefore, the diagram does not contain those portions for which no description is needed, and of the illustrated portions, shared portions have been given like reference numerals, a description thereof having been omitted unless there is a particular need. 
       FIG. 66A  is a cross-sectional view in which the mobile telephone  3901  of the forty-third embodiment is viewed in profile as being cut in a plane that is perpendicular to the upper surface  3907   a  thereof and to the display surface of the GUI display unit  3405 .  FIG. 66B  is a cross-sectional view in which the B-B cross-section of  FIG. 66A  is viewed from above the mobile telephone  3901 . In the forty-third embodiment of  FIG. 66 , similarly with respect to the forty-second embodiment of  FIG. 65 , the one end in the piezoelectric bimorph element  2525  to which the terminal  2525   b  is not provided serves as a holding end  2525   c  and is supported by a cantilever structure. A point of difference in the forty-third embodiment from the forty-second embodiment lies in that, as is clear from  FIG. 66A , the piezoelectric bimorph element  2525  is arranged in parallel to the side surface of the mobile telephone  3901 , similarly with respect to the thirty-ninth embodiment in  FIG. 61  and the modification examples thereof. Further, the primary vibration direction of the piezoelectric bimorph element  2525  is the direction that is perpendicular to the display surface of the GUI display unit  3405 , as illustrated by arrow  25 M. 
     Accordingly, in the forty-third embodiment of  FIG. 66  as well, an upper part corner  3924 , which is a site on the chassis of the mobile telephone  3901  appropriate for being brought up against the tragus or other ear cartilage, vibrates particularly efficiently, and the structure of the upper part corner  3924  can avoid being low in terms of collision resistance. Specifically, similarly with respect to the forty-second embodiment, as illustrated in  FIGS. 66A and 66B , one end of the piezoelectric bimorph element  2525  is inserted into and held in a hole of the support structure  3900   a  extending inward from the side surface and the top surface of the mobile telephone  3901 , as a holding end  2525   c . Accordingly, the one end of the piezoelectric bimorph element  2525  to which the terminal  2525   b  is not provided is made into a holding terminal  2525   c  in the forty-third embodiment as well, whereby the support position can be brought closer to the vicinity of the upper part corner  3924 . This embodiment is otherwise consistent with the forty-second embodiment, and therefore a description has been omitted. 
       FIG. 66C  is a first modification example of the forty-third embodiment; the piezoelectric bimorph element  2525  is held such that the primary vibration direction becomes the direction perpendicular to the side surface  3907 , as illustrated by arrow  25 N. The configuration is otherwise similar to that of the forty-third embodiment in  FIGS. 66A and 66B , and therefore a description thereof has been omitted. The first modification example in  FIG. 66C  has a large vibration component in the direction perpendicular to the side surface  3907 , and is therefore suited for usage in which the side surface  3907  of the mobile telephone  3901  is brought up against the ear cartilage and contact between the face and the display surface of the GUI display unit  3405  is avoided. In the first modification example in  FIG. 66C , similarly with respect to the forty-third embodiment in  FIGS. 66A and 66B , the display surface side of the mobile telephone  3901  can be brought up against the ear cartilage for use. In such a case as well, in a case in which the upper part corner  3924  is pushed against the ear cartilage, increasing the force thereof makes it possible to obstruct the external auditory meatus with the tragus, and to readily create the earplug bone conduction effect. 
       FIG. 66D  is a second modification example of the forty-third embodiment. The primary vibration direction is inclined 45° relative to the side surface  3907 , as illustrated by arrow  25 P. The vibration components are thereby broken down into the direction that is perpendicular to the side surface  3907  and to the direction that is perpendicular to the display surface of the GUI display unit  3405 , which is orthogonal thereto, and comparable cartilage conduction can be obtained regardless of the direction from which the upper part corner  3924  comes into contact with the ear cartilage. 
     Forty-Fourth Embodiment 
       FIG. 67  is a cross-sectional view relating to a forty-fourth embodiment according to an aspect of the present invention, and is configured as a mobile telephone  4001 . The forty-fourth embodiment is consistent with the thirty-eighth embodiment illustrated in  FIGS. 58 to 60 , except for the structure and arrangement of the cartilage conduction vibration source  2525 , which is constituted of a piezoelectric bimorph element, and except for the holding structure thereof. Therefore, the diagram does not contain those portions for which no description is needed, and of the illustrated portions, shared portions have been given like reference numerals, a description thereof having been omitted unless there is a particular need. 
       FIG. 67A  is a cross-sectional view (which includes a partial conceptual block diagram) in which the mobile telephone  4001  of the forty-fourth embodiment is viewed from above as being cut in a plane that is perpendicular to the side surface thereof and to the display surface of the GUI display unit  3405 , and is a cross-sectional view that can be understood to be similar with respect to the forty-second embodiment of  FIG. 65A . FIGS.  67 B 1  and  67 B 2  are cross-sectional views in which the B 1 -B 1  cross-section and B 2 -B 2  cross-section of the elements in  FIG. 67A  are viewed from the side of the mobile telephone  4001 , respectively.  FIG. 67C  is a detailed cross-sectional view of the important elements of  FIG. 67A  (including a partial conceptual block diagram). Portions in FIGS.  67 B 1 ,  67 B 2 , and  67 C that correspond to  FIG. 67A  have been given like reference numerals, and a description thereof has been omitted unless there is a particular need. 
     The forty-fourth embodiment of  FIG. 67 , similarly with respect to the forty-second embodiment of  FIG. 65 , has the piezoelectric bimorph element  2525  supported in parallel with the top surface, but differs from the forty-second embodiment in that the one end side to which the terminal  2525   b  is provided is supported by the cantilever structure, and in that a circuit  4036  for driving the piezoelectric bimorph element  2525  is integrated with the piezoelectric bimorph element  2525  for a configuration as a vibration unit. This embodiment is consistent with the forty-second embodiment in that the upper part corner, which is an appropriate site on the chassis of the mobile telephone  4001  to be brought up against the tragus or other ear cartilage, vibrates particularly efficiently, and also in that the upper part corner avoids having a structure that is low in terms of collision resistance. 
     Specifically, as illustrated in  FIGS. 67A and 67C , the terminal  2525   b  of the piezoelectric bimorph element  2525  is connected to a circuit  4036  that is mounted onto the terminal  2525   b  using a wire  4036   a . The terminal  2525   b  of the piezoelectric bimorph element  2525  and the circuit  4036  are re-packaged using a resin package  4025  having an acoustic impedance approximating that of the resin in which the piezoelectric bimorph element  2525  has been packaged, and are integrated as a vibration unit. A connection pin  4036   b  penetrates the resin package  4025 , projects outward from the circuit  4036 , and makes contact with a controller and power supply unit  4039  secured to the chassis of the mobile telephone  4001 . 
     As illustrated in  FIG. 67C , the circuit  4036  comprises an amp  4036   c  for boosting the drive voltage of the piezoelectric bimorph element  2525 , and an adjustment unit  4036   d  for electrically compensating for the variances of the piezoelectric bimorph element  2525 . The adjustment unit  4036   d  performs adjustments so as to operate to prevent variances in the piezoelectric bimorph element  2525  relative to the power feed and control from the controller and power supply unit  4039 ; therefore, after adjustments are done, repackaging is done with the resin  4024 . As an alternative configuration, it is possible for repackaging to be performed so that an adjustment operation unit or adjustment circuit pattern of the adjustment unit  4036   d  is exposed on the surface of the resin package  4025 , and so that adjustments can be performed after assembly. 
     In the forty-fourth embodiment of  FIG. 67 , similarly with respect to the forty-second embodiment, a support structure  4000   a  extending inward from the side surface and top surface  4007   a  of the mobile telephone  4001  is provided, a portion of the resin package  4025  of the vibration unit formed by repackaging being inserted into a hole thereof, whereby the piezoelectric bimorph element  2525  is held. As has already been described, in the forty-fourth embodiment, one end side to which the terminal  2525   b  is provided is supported, and one end  2525   c  to which the terminal  2525   b  is not provided serves as a unrestrictedly vibrating end. The counteraction of the free vibration of the one end  2525   c  is then transmitted to the chassis of the mobile telephone  4001  via the support structure  4000   a  from the resin package  4025 . 
     The various features indicated in the embodiments of the present invention can be unrestrictedly substituted or combined whenever the benefits thereof can be utilized. For example, in the forty-fourth embodiment of  FIG. 67 , the piezoelectric bimorph element  2525  is supported in parallel with the top surface, and the primary vibration direction thereof becomes the direction perpendicular to the display surface of the GUI display unit  3405 , as illustrated by arrow  25 H. However, the integrated packaging structure of the piezoelectric bimorph element  2525  and the circuit  4036  illustrated in the forty-fourth embodiment is not to be limited to the arrangement of  FIG. 67 , but rather can be utilized in a support arrangement such as in the modification example of the forty-second embodiment illustrated in  FIGS. 65C and 65D , and in the forty-third embodiment illustrated in  FIGS. 66A to 66D  and the modification example thereof. The utilization thereof may be done in conformity with the relationships between  FIGS. 65A and 67A , and in each case, the one end of the side of the piezoelectric bimorph element  2525  to which the terminal  2525   b  is provided serves as the support side, similarly with respect to  FIG. 65A . 
     The support structures  3800   a ,  3900   a , and  4000   a  in the forty-second embodiment of  FIG. 65  to the forty-fourth embodiment in  FIG. 67  are also not limited as extending inward from the side surface and top surface of the mobile telephone  4001 ; rather, a variety of support structures are possible. For example, a support structure may be configured so as to extend from only one of either the side surface or the top surface. Moreover, a variety of other structures are possible, including one extending from either the front surface or the back surface, one extending from the front surface and the top surface; one extending from the rear surface and the top surface; one extending from the side surface and the front surface; one extending from the side surface and the rear surface; or one extending from the rear side of the corner part as an elongation from all three of the top surface, the side surface, and the front surface. In each case, providing the piezoelectric bimorph element  2525  or the support unit of the resin packaging  4025  integrated therewith to the inner side of the chassis in the vicinity of the corner part can allow the corner part to avoid having a structure that is low in terms of collision resistance while also causing the corner part to vibrate efficiently due to the counteraction of the free vibration of the other end. 
     The various features indicated in each of the embodiments of the present invention are also not necessarily specific to individual embodiments; rather, the features of each respective embodiment can be modified and used or combined and used as appropriate, whenever it is possible to utilize the benefits thereof. For example, in the first embodiment of  FIG. 1 , the second embodiment of  FIG. 5 , the third embodiment of  FIG. 6 , and the thirty-fifth embodiment of  FIG. 55 , the interior of the mobile telephone is provided with two piezoelectric bimorph elements respectively for right ear use and left ear use. However, examples in which each of a plurality of piezoelectric bimorph elements is provided to a plurality of places in the mobile telephone in order to obtain desired cartilage conduction from a plurality of directions are not to be limited to these embodiments. On the other hand, in the thirty-ninth embodiment of  FIG. 61 , the fortieth embodiment of  FIG. 62 , the second modification example of the forty-second embodiment in  FIG. 65D , and the second modification example of the forty-third embodiment in  FIG. 66D , a single primary vibration direction of the piezoelectric bimorph element is given an incline and the vibration component is divided in a case in which cartilage conduction is to be generated in a plurality of directions, such as between the side surface and the front surface or between the top surface and the front surface; however, configurations for generating cartilage conduction in a plurality of directions are not to be limited to these embodiments. 
     Forty-Fifth Embodiment 
       FIG. 68  is a cross-sectional view relating to the forty-fifth embodiment according to an aspect of the present invention, and serves to illustrate another example relating to the configuration described above in which cartilage conduction is generated in a plurality of directions, such as between the side surface and front surface, and between the top surface and the front surface. Specifically, in a mobile telephone  4101   a  of the forty-fifth embodiment illustrated in  FIG. 68A  and a mobile telephone  4101   b  of a modification example thereof illustrated in  FIG. 68B , two piezoelectric bimorph elements are utilized in imitation of the thirty-fifth embodiment of  FIG. 55  and the like, instead of the dividing of the vibration component of a single piezoelectric bimorph elements such as in the fortieth embodiment of  FIG. 62 . Then, the primary vibration directions of these piezoelectric bimorph elements  4124  and  4126  are set off from each other by 90° so as to become parallel to the front surface and side surface or to the front surface and top surface, respectively, the bimorph elements being supported on the inner side of the chassis of the mobile telephone. Similarly with respect to the fortieth embodiment of  FIG. 62 , cartilage conduction is thereby generated in a plurality of directions, such as between the side surface and front surface or between the top surface and front surface. The configuration of the forty-fifth embodiment of  FIG. 68  is shared with that of the fortieth embodiment of  FIG. 62 , other than the fact that two piezoelectric bimorph elements are utilized; therefore, identical portions have been given like reference numerals, and extraneous description has been omitted. It shall be noted that  FIGS. 68A and 68B  correspond to  FIGS. 62A and 62C , respectively. 
     In  FIG. 68 , the longitudinal directions of the two piezoelectric bimorph elements illustrate a parallel arrangement, but the arrangement of the plurality of piezoelectric bimorph elements is not limited thereto. For example, another possible arrangement is one in which the longitudinal directions of the two piezoelectric bimorph elements are mutually orthogonal, where one is along the top surface and the other is along the side surface. Furthermore, the support of the plurality of piezoelectric bimorph elements in which the primary vibration directions are set off from each other is not limited to the inner side of the chassis of the mobile telephone as in  FIG. 68 ; rather, for example, the support may be on the outer side of the chassis, as in the thirtieth and thirty-first embodiments and the modification examples thereof illustrated in  FIGS. 48 to 50 . 
     Forty-Sixth Embodiment 
       FIG. 69  is a perspective view and a cross-sectional view relating to a forty-sixth embodiment according to an aspect of the present invention, and is configured as a mobile telephone  4201 . The forty-sixth embodiment is consistent with the thirty-eighth embodiment illustrated in  FIGS. 58 to 60 , except for the arrangement of the cartilage conduction vibration source  2525 , which is constituted of a piezoelectric bimorph element, and except for the holding structure thereof; therefore, the diagram does not contain those portions for which no description is needed, and of the illustrated portions, shared portions have been given like reference numerals, a description thereof having been omitted unless there is a particular need. 
       FIG. 69A  is a perspective view in which the mobile telephone  4201  of the forty-fourth embodiment is viewed from the front surface; the four corner parts, which are susceptible to collision when the mobile telephone  4201  is dropped by mistake or in other circumstances, are provided with elastic body units  4263   a ,  4263   b ,  4263   c ,  4263   d , which serve as protectors. The inner sides of the elastic body units  4263   a  and  4263   b  found at the two upper corner parts have a dual purpose as units for holding the piezoelectric bimorph element, and the outer sides of the elastic body units  4263   a  and  4263   b  have a dual purpose as cartilage conduction units for making contact with the ear cartilage. For this reason, at least the elastic body units  4263   a  and  4263   b  utilize an elastic material having an acoustic impedance approximating that of ear cartilage (a silicone rubber; a mixture of a silicone rubber and a butadiene rubber; a natural rubber; a structure formed using these varieties of rubber in which air bubbles are sealed; a structure, such as can be seen in transparent packaging sheet materials and the like, in which a layer of groups of air bubbles is sealed separated by a thin film of synthetic resin; or the like). 
       FIG. 69B  is a cross-sectional view in the B 1 -B 1  sectional plane of  FIG. 69A , with a cross-section of the mobile telephone  4201  in the plane perpendicular to the front surface and the side surface. As is clear from  FIG. 69B , the two ends of the piezoelectric bimorph element  2525  are supported by the inner sides of the elastic body units  4263   a  and  4263   b . The elastic body unit  4263   a  supports the terminal  2525   b  side of the piezoelectric bimorph element  2525 , and a flexible wiring  3836   a  for establishing a connection between the terminal  2525   b  and the circuit  3836  passes through the elastic body unit. 
     The elastic body units  4263   a  and  4263   b  are anchoringly supported on the chassis of the mobile telephone  4201 , but the two ends of the piezoelectric bimorph element  2525  are ensured a certain degree of freedom to move by vibration, due to the elasticity of the elastic body units  4263   a  and  4263   b , and the vibration of the piezoelectric bimorph element  2525  is less hampered. The middle part of the piezoelectric bimorph element  2525  is not in contact with anything and is free to vibrate. The outer sides of the elastic body units  4263   a  and  4263   b , serve as an outer wall of the corner parts of the mobile telephone  4201 , and have a dual purpose in acting as protectors for collisions with an external unit, and as cartilage conduction units for making contact with the ear cartilage. The mobile telephone  4201  can thereby be brought into contact with either of the right ear or the left ear for the purpose of cartilage conduction, as has been described in, for example, the first embodiment in  FIGS. 2A and 2B . Furthermore, because the elastic body units  4263   a  and  4263   b  have a different acoustic impedance from that of the chassis of the mobile telephone  4201 , the conduction component from the elastic body units  4263   a  and  4263   b  to the chassis of the mobile telephone  4201  can be reduced, and efficient cartilage conduction from the elastic body unit  4263   a  or  4263   b  to the ear cartilage can be achieved. 
       FIG. 69C  is a cross-sectional view in the B 2 -B 2  sectional plane illustrated in  FIG. 69A  or  FIG. 69B , with a cross-section of the mobile telephone  4201  in the plane perpendicular to the front surface and the top surface. It can be understood from  FIG. 69C  as well that the elastic body units  4263   a  and  4263   b  hold the piezoelectric bimorph element  2525  and are anchoringly supported on the chassis of the mobile telephone  4201 , and also that the outer sides thereof, without the outer wall of the corner parts of the mobile telephone  4201 , serve as protectors for collisions with an external unit, and have a dual purpose as cartilage conduction units for making contact with the ear cartilage. As is clear from  FIG. 69C , the forty-sixth embodiment assumes a structure in which the elastic body units  4263   c  and  4263   d , which are at the lower two corners, function exclusively as protectors, and are covered by the chassis of the mobile telephone  4201 . 
     Forty-Seventh Embodiment 
       FIG. 70  relates to the forty-seventh embodiment according to an aspect of the present invention;  FIG. 70A  is a perspective view illustrating a part of the upper end side thereof, and  FIG. 70B  is a cross-sectional view illustrating the B-B cross-section of  FIG. 70A . The seventieth embodiment is configured as a mobile telephone  4301 , and assumes a structure in which the piezoelectric bimorph element  2525  is fitted into the side surface of the mobile telephone. Such a structure has much in common with the thirtieth embodiment illustrated in  FIG. 48 , and therefore common portions have been given like reference numerals, and a description thereof has been omitted. Further, similarly with respect to  FIG. 48 ,  FIG. 70  omits an illustration and description of the configuration for inputting an audio signal into the cartilage conduction vibration source  2525 , and the like. 
     A point of difference in the forty-seventh embodiment of  FIG. 70  from the thirtieth embodiment of  FIG. 49  lies in the structure of the portions for transmitting the vibration of the piezoelectric bimorph element  2525  to the ear cartilage. Namely, in the forty-seventh embodiment of  FIG. 70 , the side surface of the mobile telephone  4301  is provided with a concavity  4301   a  that has a very slight step (for example, 0.5 mm), and is arranged such that the vibration plane of the piezoelectric element  2525  comes to a bottom part of this concavity  4301   a . The vibration plane of the piezoelectric bimorph element  2525  may be exposed at the bottom part of the concavity  4301   a , but in the forty-seventh embodiment, the piezoelectric bimorph element  2525  is covered with a thin protective layer  4227 . This protective layer  4227  is applied or coated on with an elastic material, in order to prevent stretching of the vibration plane due to vibration of the piezoelectric bimorph element  2525  from being hampered. 
     Due to the structure described above, it is possible to bring the vibration plane of the piezoelectric bimorph element  2525  into direct contact with the ear cartilage wherever possible, and also it is possible to provide protection against damage to the piezoelectric bimorph element  2525  from any collision with an external unit. Specifically, the piezoelectric bimorph element  2525  is arranged at the bottom of the concavity  4301   a  and is at a position that is lower only by the step from the outer surface of the chassis of the mobile telephone  4301 ; because of the step, the piezoelectric bimorph element  2525  will not directly collide with an external unit even were the side surface of the chassis of the mobile telephone to collide with an external unit. As illustrated in  FIG. 70A , in the forty-seventh embodiment, the concavity  4301   a  is provided to a place slightly lowered from the corner part in the side surface of the mobile telephone  4301 , to prevent any damage to the piezoelectric bimorph element  2525  due to collision at the corner part. Ear cartilage is soft; therefore, it is readily deformed at the place of the very slight step and can be brought into contact with the vibration plane of the piezoelectric bimorph element  2525  or the covered surface thereof, even with an arrangement such that the vibration plane of the piezoelectric bimorph element  2525  comes to the bottom part of the concavity  4301   a.    
     The various features indicated in the various embodiments of the present invention can be unrestrictedly modified, substituted or combined whenever the benefits thereof can be utilized. For example, the elastic body units  4263   a  and  4263   b  are arranged in the forty-sixth embodiment of  FIG. 69  so as to be symmetrical relative to the center of the piezoelectric bimorph element  2525 , but the support of the piezoelectric bimorph element  2525  is not to be limited to such an arrangement; another possible arrangement is an eccentric one in which the center of the piezoelectric bimorph element  2525  is closer to either of the opposing corner parts. For example, the piezoelectric bimorph element  2525 , rather than being completely symmetrical relative to the center thereof, has a slightly different weight and degree of freedom to vibrate at the side that is not the side that has the terminal  2525   b . The wiring  3836   a  also passes through the elastic body unit  4263   a  for supporting the terminal  2525   b , and passes through to the circuit  3836 . The configuration for eccentrically supporting the piezoelectric bimorph element  2525  between the two corner parts is effective in compensation for asymmetry such as described above. The respective lengths of the elastic body units  4263   a  and  4263   b  must be determined depending on the length of the piezoelectric bimorph element  2525  and on the width of the chassis of the mobile telephone  4201 . In other words, the elastic body units  4263   a  and  4263   b  require enough length to reach up to the two ends of the piezoelectric bimorph element  2525  from the outer surface of the two corner parts of the chassis of the mobile telephone  4201 . The configuration for eccentrically supporting the piezoelectric bimorph element  2525  between the two corner parts is effective in that the length can be adjusted as above while keeping the layout of the implemented parts inside the mobile telephone in consideration. In a case in which the elastic body unit  4263   a  or  4263   b  becomes longer, the configuration is such that the elastic body unit  4263   a  or  4263   b  is elongated inward so as not to make contact with the inner surface of the chassis, and reaches the end part of the piezoelectric bimorph element  2525 , whereby it is also possible to increase the degree of freedom with which the end part of the piezoelectric bimorph element  2525  vibrates. 
       FIG. 71  is a perspective view and a cross-sectional view relating to a modification example of the forty-sixth embodiment according to an aspect of the present invention, and serves to illustrate the implementation of a configuration in a case in which the elastic body unit is longer, as described above. Specifically, a case in which, as illustrated in  FIG. 71 , the elastic body units  4263   a  and  4263   b  become longer utilizes a configuration in which there are provided elongation units  4263   e  and  4263   f , by which the elastic body units  4263   a  and  4263   b  are elongated inward so as not to make contact with the inner surface of the chassis of the mobile telephone  4201 , the two end parts of the piezoelectric bimorph element  2525  being held by these elongation units  4263   e  and  4263   f . According to such a configuration, the elongation units  4263   e  and  4263   f  do not make contact with the inner surface of the chassis of the mobile telephone  4201 , and therefore elastic deformation is readily possible, and the two end parts of the piezoelectric bimorph element  2525  can be held by such elongation units  4263   e  and  4263   f , whereby the degree of freedom with which the piezoelectric bimorph element  2525  vibrates can be increased. The configuration of  FIG. 71  is otherwise consistent with that of  FIG. 69 , and therefore shared portions have been given like reference numerals, and a description thereof has been omitted. 
     The various features indicated in the various embodiments of the present invention can be unrestrictedly modified, substituted, or combined whenever the benefits thereof can be utilized. For example, each of the embodiments above has been described with the cartilage conduction vibration source comprising a piezoelectric bimorph element or the like. However, barring particular cases described as pertaining to a configuration specific to the piezoelectric bimorph element, the various features of the present invention are not to be limited to cases in which a piezoelectric bimorph element is utilized as the cartilage conduction vibration source; the advantages thereof can also be realized in a case in which an electromagnetic vibrating element, a super magnetostrictive element, or other diverse elements are used for the cartilage conduction vibration source. 
     Forty-Eighth Embodiment 
       FIG. 72  is a perspective view and a cross-sectional view relating to a forty-eighth embodiment according to an aspect of the present invention, and is configured as a mobile telephone  4301 . The forty-eighth embodiment serves as an example of a case in which an electromagnetic vibrating element is used as the cartilage conduction vibration source in the configuration of the forty-sixth embodiment in  FIG. 69 .  FIG. 72A  is a perspective view in which the mobile telephone  4301  of the forty-eighth embodiment is viewed from the front surface thereof; the outer appearance is similar to that of the perspective view of the forty-sixth embodiment in  FIG. 69A . In other words, in the forty-eighth embodiment as well the four corner parts, which are susceptible to collision when the mobile telephone  4301  is dropped by mistake or in other circumstances, are provided with elastic body units  4363   a ,  4363   b ,  4363   c , and  4363   d , which serve as protectors. The elastic body units  4363   a  and  4363   b , which are at the upper two corners, have a dual purpose as units for holding the cartilage conduction vibration source, and the outer sides of the elastic body units  4363   a  and  4363   b  have a dual purpose as cartilage conduction units for making contact with the ear cartilage. Then, the elastic body units  4363   a  and  4363   b , similarly with respect to the forty-sixth embodiment, utilize an elastic material having an acoustic impedance approximating that of ear cartilage (a silicone rubber; a mixture of a silicone rubber and a butadiene rubber; a natural rubber; a structure formed using these varieties of rubber in which air bubbles are sealed; a structure, such as can be seen in transparent packaging sheet materials and the like, in which a layer of groups of air bubbles is sealed separated by a thin film of synthetic resin; or the like). 
       FIG. 72B  is a cross-sectional view in the B-B sectional plane of  FIG. 72A , wherein the mobile telephone  4301  (represented as  4301   a  in  FIG. 72B ) is sectioned along the plane perpendicular to the front surface and the side surface. As is clear from  FIG. 72B , each of electromagnetic vibrating elements  4326   a  and  4324   a  is embedded in the elastic body units  4363   a  and  4363   b , respectively. The primary vibration direction thereof is the direction perpendicular to the front surface of the mobile telephone  4301  to which a GUI display unit is provided, as illustrated by arrow  25 M. In the configuration in which the electromagnetic vibrating elements  4326   a  and  4324   a  or other cartilage conduction vibration sources are embedded in the elastic body units  4363   a  and  4363   b , the elastic body units  4363   a  and  4363   b  have a dual purpose as a protector function and a cartilage conduction unit function, as described above, and also, as described in the embodiment of  FIG. 17 , additionally have yet another purpose as a cushioning function for guarding the cartilage conduction vibration source against impact. 
     In the configuration in which, as in the forty-eighth embodiment in  FIG. 72B , the separate electromagnetic vibrating elements  4326   a  and  4324   a  are provided to the elastic body unit  4363   a  and  4363  respectively, the electromagnetic vibrating elements  4326   a  and  4324   a  can be controlled independently. Accordingly, similarly with respect to the first embodiment illustrated in  FIGS. 1 to 4 , the configuration can be made to be such that the inclined direction of the mobile telephone  4301  is detected according to the gravity acceleration detected by the acceleration sensor, and, in accordance with which of the elastic body units  4363   a  and  4363   b  is brought up against the ear (in other words, in accordance with against which among the right ear and left ear the corner part of the mobile telephone has been brought, as illustrated in  FIG. 2 ), the electromagnetic vibrating element on the side at the lower angle of inclination is made to vibrate, and the other is turned off. This is also similar to a modification example that will be described later. 
       FIG. 72C  is a cross-sectional view of the first modification example of the forty-eighth embodiment, and, similarly with respect to  FIG. 72B , is a cross-sectional view in the B-B sectional plane of  FIG. 72A , wherein the mobile telephone  4301  (represented as  4301   b  in  FIG. 72C ) is sectioned along the plane perpendicular to the front surface and the side surface. Similarly with respect to the forty-eighth embodiment, the first modification example also has the electromagnetic vibrating elements  4326   b  and  4324   b  embedded in the elastic body units  4363   a  and  4363   b , respectively. However, the primary vibration direction thereof becomes the direction perpendicular to the side surface of the mobile telephone  4301 , as illustrated by arrow  25 N. This modification example is otherwise similar to the forty-eighth embodiment of  FIG. 72B . 
       FIG. 72D  is a cross-sectional view of the second modification example of the forty-eighth embodiment, and, similarly with respect to  FIG. 72B , is a cross-sectional view in the B-B sectional plane of  FIG. 72A , wherein the mobile telephone  4301  (represented as  4301   c  in  FIG. 72D ) is sectioned along the plane perpendicular to the rear surface and the side surface. In the second modification example, similarly with respect to the forty-eighth embodiment, each of the electromagnetic vibrating elements  4326   c  and  4324   c  is embedded in the elastic body units  4363   a  and  4363   b , respectively. However, the primary vibration direction thereof becomes a direction inclined 45° from the side surface of the mobile telephone  4301 , as illustrated by arrow  25 P. For this reason, similarly with respect to the second modification example of the forty-third embodiment in  FIG. 66D , the vibration components are broken down into the direction that is perpendicular to the side surface and to the direction that is perpendicular to the front surface, which is orthogonal thereto, and comparable cartilage conduction can be obtained regardless of the direction from which the either the elastic body unit  4363   a  or  4363   b  comes into contact with the ear cartilage. This modification example is otherwise similar to the forty-eighth embodiment of  FIG. 72B . 
       FIG. 72E  is a cross-sectional view of the third modification example of the forty-eighth embodiment, and, similarly with respect to  FIG. 72B , is a cross-sectional view in the B-B sectional plane of  FIG. 72A , wherein the mobile telephone  4301  (represented as  4301   d  in  FIG. 72E ) is sectioned along the plane perpendicular to the front surface and the side surface. In the third modification example, electromagnetic vibrating elements  4326   d ,  4326   e , and  4324   d ,  4324   e  are embedded in the elastic body units  4363   a ,  4363   b , respectively. The vibration direction of the electromagnetic vibrating elements  4326   d  and  4324   d  is the direction perpendicular to the side surface, illustrated by arrow  25 D, and that of the electromagnetic vibrating elements  4326   e  and  4324   e  becomes the direction perpendicular to the front surface, illustrated by arrow  25 E. Similarly with respect to the forty-fifth embodiment illustrated in  FIG. 68 , earplug bone conduction is thereby generated to the side surface and the front surface from a plurality of different cartilage conduction vibration sources. 
     In the configuration in which, as in the third modification example of the forty-eighth embodiment in  FIG. 72E , vibration that is directed perpendicularly with respect to the side surface is generated from the electromagnetic vibrating element  4324   d  and the like and vibration that is directed perpendicularly with respect to the front surface is generated from the electromagnetic vibrating element  4324   e  and the like, it is possible to independently control the electromagnetic vibrating elements  4324   d  and  4324   e  having different vibration directions. Specifically, a possible configuration is one in which the incline direction of the mobile telephone  4301  is detected by gravity acceleration, which is detected by an acceleration sensor such as the acceleration sensor  49  of the first embodiment illustrated in  FIG. 3 , where, in accordance with whether the elastic body unit  4363   b  is brought up against the ear from the side surface or the front surface, the electromagnetic vibrating element on the side brought up against the ear is made to vibrate and the vibration of the other one is turned off. Such independent control of the plurality of cartilage conduction vibration sources having different vibration directions is not limited to the case of the electromagnetic vibrating elements in  FIG. 72D ; rather, there are other possible cases of configurations in which, for example, the piezoelectric bimorph elements  4124  and  4126  of the forty-fifth embodiment illustrated in  FIG. 68  are utilized. 
       FIG. 73  is an enlarged cross-sectional view of the elements of the forty-eighth embodiment and the modification examples thereof.  FIG. 73A  enlarges the portions of the elastic body unit  4363   b  and the electromagnetic vibrating element  4324   a  of  FIG. 72B , and in particular provides a detailed illustration of the electromagnetic vibrating element  4324   a . The electromagnetic vibrating element  4324   a  has a yoke  4324   h  for holding a magnet  4324   f  and a central magnetic pole  4324   g  in a housing thereof, the yoke being suspended midair in a corrugation damper  4324   i . A top plate  4324   j , which has a gap, is anchored to the magnet  4324   f  and the central magnetic pole  4324   g . The magnet  4324   f , the central magnetic pole  4324   g , the yoke  4324   h , and the top plate  4324   j  become integrally movable in the vertical direction when viewed in  FIG. 73  relative to the housing of the electromagnetic vibrating element  4324   a . On the other hand, a voice coil bobbin  4324   k  is anchored to the inside of the housing of the electromagnetic vibrating element  4324   a , and a voice coil  4323   m  wrapped therearound penetrates into the gap of the top plate  4324   j . In such a configuration, when an audio signal is inputted into the voice coil  4323   m , relative displacement occurs between the yoke  4324   h  and the like, and the housing of the electromagnetic vibrating element  4324   a ; the vibration thereof is transmitted to the ear cartilage in contact therewith via the elastic body unit  4363   b.    
       FIG. 73B  illustrates a fourth modification example of the forty-eighth embodiment, and provides an enlarged illustration of the portions corresponding to  FIG. 73A . The internal configuration of the electromagnetic vibrating element  4324   a  is similar to that of  FIG. 73A ; therefore, to avoid complication, an illustration of the reference numerals of each unit has been omitted, and the description thereof has also been left out. The fourth modification example in  FIG. 73B  assumes a configuration in which the corner part of the mobile telephone  4401  is provided with a stepped unit  4401   g , the outer side thereof being covered by the elastic body unit  4463   b . The front surface side of the stepped unit  4401   g  is provided with a window unit  4401   f , the electromagnetic vibrating element  4324   a  being bonded to the rear side of the elastic body unit  4463   b  that faces the portion of the window unit  4401   f . A cushioning unit  4363   f  comprising an elastic body is also bonded to the opposite side of the electromagnetic vibrating element  4324   a . The cushioning unit  4363   f  is provided with a gap so as to not be in contact with the rear side of the stepped unit  4401   g  in the ordinary vibrating state, and acts as a cushioning material for preventing the elastic body unit  4463   b  thereabove from making contact with and being unrestrictedly pushed into the rear side of the stepped unit  4401   g  when there is an excessive push against the elastic body unit  4463   b  from collision with an external unit or the like. Adverse events such as when the electromagnetic vibrating element  4324   a  detaches due to deformation of the elastic body unit  4463   b  are thereby prevented. The cushioning unit  4363   f  functions as a balancer in the ordinary vibrating state, and therefore the shape and weight thereof or the like can be adjusted to design the electromagnetic vibrating element  4324   a  to have optimal acoustic properties. The cushioning unit  4363   f  may be a rigid body rather than an elastic body in a case of functioning only as a balancer. Although not depicted in  FIG. 73B , the corner part of the opposite side in the fourth modification example of the forty-eighth embodiment (corresponding to the position of the elastic body unit  4363   a  in  FIG. 72B ) also assumes a configuration having left-right symmetry with  FIG. 73B . 
     The fourth modification example in  FIG. 73B  is based on the arrangement of the electromagnetic vibrating elements in the orientation in  FIG. 72B . However, a configuration such as that of the fourth modification is not limited thereto, and can also be applied to the arrangement of the electromagnetic vibrating elements in the various orientations in  FIGS. 72C to 72E . 
     In the forty-eighth embodiment illustrated in  FIGS. 72 and 73A , the elastic body unit  4363   b  and the electromagnetic vibrating element  4324   a  are configured as replaceable unit parts. When the outer appearance of the elastic body unit  4363   b  is sullied by collision with an external unit, in terms of aesthetics, the elastic body unit  4363   b  and the electromagnetic vibrating element  4324   a  can be replaced as a unit. This is a point of similarity with the fourth modification example of the forty-eighth embodiment illustrated in  FIG. 73B  as well; the elastic body unit  4463   b , the electromagnetic vibrating element  4324   a , and the cushioning unit  4363   f  are configured as a replaceable unit part. When the outer appearance of the elastic body unit  4463   b  is damaged in terms of aesthetics, the whole can be replaced as a unit. Such a configuration as a unit part is a useful feature that is consistent with the fact that the elastic body unit  4463   b  or the like is configured as a protector and is a part positioned at a corner part predicted to collide with an external unit. The configuration is also a useful feature that is consistent with the fact that the corner susceptible to collision is a suitable location for making contact for cartilage conduction. Furthermore, the feature in which the cartilage conduction vibration units are configured as replaceable unit parts is fundamentally consistent with the configuration of the other portions of the mobile telephone, and is useful in providing a commercial product to which cartilage conduction vibration units having acoustic properties that are optimized in accordance with the user&#39;s age or other parameters (for example, where the shape and/or weight of the cushioning unit  4363   f  illustrated in  FIG. 73B  are adjusted) are attached. The feature is also fundamentally consistent with the configuration of the other portions of the mobile telephone and is useful in providing a commercial product that can be modified not only for acoustic properties but also in accordance with user preferences; for example, in accordance with a request regarding which of the cartilage conduction vibration units from  FIGS. 72B to 72E  is used. 
     The specific configuration in which the cartilage conduction vibration source is provided to the elastic body unit of the corner part is not limited to what is illustrated in  FIG. 73 ; the design can be modified where appropriate. For example, the cushioning unit  4363   f  illustrated in  FIG. 73B  may be bonded to the rear side of the stepped unit  4401   g , instead of being bonded to the opposite side of the electromagnetic vibrating element  4324   a . In such a case, the cushioning unit  4363   f  is provided with a gap so as to prevent contact with the opposite side of the electromagnetic vibrating element  4324   a  in the ordinary vibrating state. The cushioning unit  4363   f  may also be omitted in a case in which the elastic body unit  4463   b  is able to withstand pushing due to collision with an external unit or another cause. 
     The various features of each of the embodiments described above are not to be limited to the above embodiments; rather, wherever it is possible to benefit from the feature of an embodiment, same can also be implemented in other embodiments. The various features of each of the embodiments described above are not to be restricted to individual respective embodiments, but rather can be substituted or combined with other appropriate embodiments. The forty-eighth embodiment and the modification examples thereof serve as illustrations of examples in which the electromagnetic vibrating element is utilized as a cartilage conduction vibration unit and in which independently controllable and separate electromagnetic vibrating elements are provided to the elastic body units at different corners. However, the implementation of the present invention is not to be limited thereto. For example, in a case in which, as has already been described, a piezoelectric bimorph element is utilized as the cartilage conduction vibration unit, the cartilage conduction vibration units separately provided to different corners as in the first embodiment of  FIG. 1  can be controlled independent of each other. In such a case, referring to the forty-eighth embodiment, the piezoelectric bimorph element can also be provided to the elastic body units at different corners. Conversely, even a case in which an electromagnetic vibrating element is utilized as the cartilage conduction vibration unit can be configured such that the vibration of a single electromagnetic vibrating element is transmitted to the left and right corners, as in the fourth embodiment of  FIG. 7 , the fifth embodiment of  FIG. 11 , the tenth embodiment of  FIG. 19 , the eleventh embodiment of  FIG. 20 , and the like. In such a case, referring to the forty-eighth embodiment, the vibration conductors to the left and right corner parts can be constituted of elastic bodies regardless of whether the cartilage conduction vibration unit is a piezoelectric bimorph element or an electromagnetic vibrating element. Also, referring to the forty-sixth embodiment and the modification examples thereof, the configuration may be such that the two sides of the electromagnetic vibrating element are supported by elastic bodies provided to the left and right corner parts, depending on the shape of the electromagnetic vibrating element. 
     Forty-Ninth Embodiment 
       FIG. 74  is a perspective view and a cross-sectional view relating to a forty-ninth embodiment according to an aspect of the present invention as well as to a modification example thereof, and is configured as a mobile telephone  4501 . The forty-ninth embodiment is consistent with the forty-sixth embodiment of  FIG. 69  except for the configuration for switching air conduction (to be described later); therefore, like reference numerals have been assigned and the description thereof is called upon. More specifically, the forty-ninth embodiment is illustrated in  FIGS. 74A to 74D , of which  FIGS. 74A to 74C  correspond to  FIGS. 69A to 69C , which relate to the forty-sixth embodiment.  FIG. 74D  is an enlarged view of the elements of  FIG. 74C .  FIG. 74E  is an enlarged view of the elements relating to a modification of the forty-ninth embodiment. 
     As is clear from the B 2 -B 2  cross-sectional view of  FIG. 74C , the forty-ninth embodiment is provided with a transparent resonance chamber  4563  such that the display unit  3405  is covered. The transparent resonance chamber  4563  has air removal holes partially provided to the interior side of the mobile telephone  4501  in the hollow. The transparent resonance chamber  4563  is extremely thin, and therefore the user can observe the display unit  3405  through the transparent resonance chamber  4563 . As is clear from  FIGS. 74B and 74C , the middle portion of the piezoelectric bimorph element  2525  is provided with a vibration conductor  4527  that can slide in the vertical direction. When the vibration conductor  4527  is at the position indicated by the solid line illustrated in  FIG. 74C , the transmission of vibration from the middle portion of the piezoelectric bimorph element  2525  to the transparent resonance chamber  4563  is cut off, and when the vibration conductor  4527  is at the position indicated by the dotted line in  FIG. 74C  and comes into contact with the upper part of the transparent resonance chamber  4563 , the vibration of the middle portion of the piezoelectric bimorph element  2525  is transmitted to the transparent resonance chamber  4563  via the vibration conductor  4527 , whereby air conduction sound is generated from the entire transparent resonance chamber  4563  and the entire transparent resonance chamber  4563  becomes a surface speaker. This aspect is clearly illustrated by the enlarged view of the elements of  FIG. 74D . The up and down of the vibration conductor  4527  is performed by causing an external manual operation knob  4527   a  of the mobile telephone  4501  to slide up and down. The manual operation knob  4527   a  has a click function for determining the two up-down positions. The vibration conductor  4527  also is resilient so as to effectively make contact with the transparent resonance chamber  4563  when made to slide to the position of the dotted line. 
     As described above, air conduction sound is generated from the entire transparent resonance chamber  4563  and cartilage conduction is generated from the elastic body units  4263   a  and  4263   b  in the state in which the vibration conductor  4527  is at the position indicated by the dotted line in  FIGS. 74C to 74D . The user can accordingly bring the elastic body unit  4263   a  or  4263   b  up against to ear to listen to sound by cartilage conduction, and can also bring any desired portion of the display unit  3405  to which the transparent resonance chamber  4563  is provided close to or up against the ear to listen to sound by air conduction. Thus, a variety of uses become possible in accordance with the user&#39;s preferences and status. On the other hand, the transmission of vibration to the transparent resonance chamber  4563  is cut off and the generation of air conduction sound from the transparent resonance chamber  4563  can be stopped in the state in which the vibration conductor  4527  is at the position indicated by the solid line illustrated in  FIGS. 74C to 74D ; therefore, because sound leakage by air conduction is prevented, particularly in the state in which the environment is quiet, it is possible to listen to sound by cartilage conduction while preventing any disturbance to the surroundings or leakage of sensitive information. 
     The modification example of the forty-ninth embodiment in  FIG. 74E  is configured such that a vibration conductor  4527   b  is made to rotate, whereby vibration from the middle portion of the piezoelectric bimorph element  2525  is intermittently transmitted to the transparent resonance chamber  4563 . Specifically, when the vibration conductor  4527   b  is at the position indicated by the solid line illustrated in  FIG. 74E , the vibration conductor  4527   b  separates from both the middle portion of the piezoelectric bimorph element  2525  and the transparent resonance chamber  4563 , and the transmission of vibration is cut off. On the other hand, when the vibration conductor  4527   b  is rotated clockwise and is at the position indicated by the dotted line in  FIG. 74E , the vibration conductor  4527   b  is in contact with both the middle portion of the piezoelectric bimorph element  2525  and the upper part of the transparent resonance chamber  4563 , and the vibration of the middle portion of the piezoelectric bimorph element  2525  is transmitted to the transparent resonance chamber  4563  via the vibration conductor  4527   b . This modification example is otherwise similar to the forty-ninth embodiment of  FIGS. 74A to 74D . The rotation of the vibration conductor  4527   b  is performed by the rotation of an external manual operation dial  4527   c  of the mobile telephone  4501 . The manual operation dial  4527   c  has a click function for determining the two positions of the rotation. The vibration conductor  4527   b  is resilient as well, and, when rotated to the position of the dotted line, presses effectively against the middle portion of the piezoelectric bimorph element  2525  and the upper part of the transparent resonance chamber  4563 . 
     Switching between cartilage conduction and air conduction in the manner described above is not to be limited to the forty-ninth embodiment illustrated in  FIG. 74  and to the modification examples thereof; various configurations are possible. For example, in  FIG. 74 , the piezoelectric bimorph element  2525  and the transparent resonance chamber  4563  are secured, and the vibration conductor  4527  or  4527   b  is moved therebetween, whereby intermittent vibration is performed. However, intermittent vibration between the two can also be performed instead by rendering at least one of the piezoelectric bimorph element  2525  and the transparent resonance chamber  4563  movable. The movement at this time may be performed by at least a part of either the piezoelectric bimorph element  2525  or the transparent resonance chamber  4563 . Furthermore,  FIG. 74  serves to illustrate an example of switching between the case of cartilage conduction together with air conduction and the case of only cartilage conduction (to be precise, there is also a slight air conduction component, but for the sake of simplicity, this case is hereinafter referred to as “only cartilage conduction”), but another possible configuration is one in which, in exchange, the switching is between a case of only cartilage conduction and a case of only air conduction or the switching is between a case of cartilage conduction together with air conduction and a case of only air conduction. Also,  FIG. 74  serves to illustrate an example of manual switching, but another possible configuration is one in which a noise sensor for differentiating between whether the environment is quiet or not is provided and the vibration conductor  4527  or  4527   b  is automatically driven on the basis of the output of the noise sensor, whereby a case of cartilage conduction together with air conduction is automatically switched to a case of cartilage conduction only when the noise detected by the noise sensor is at or above a predetermined level. 
     Fiftieth Embodiment 
       FIG. 75  is a block diagram relating to a fiftieth embodiment according to an aspect of the present invention, and is configured as a mobile telephone  4601 . The fiftieth embodiment is based on the configuration of the third modification example of the forty-eighth embodiment, the cross-section of which is illustrated in  FIG. 72E ; the electromagnetic vibrating elements  4326   d ,  4326   e ,  4324   d , and  4324   e  thereof are controlled by a configuration that is substantially consistent with the block diagram of the first embodiment in  FIG. 3 . In terms of the need to describe the arrangement, the portions of the electromagnetic vibrating elements are illustrated by a composite of the cross-sectional views. Because the fiftieth embodiment is configured as described above, portions in  FIG. 75  that are shared with  FIGS. 3 and 72E  are assigned shared reference numerals, and a description thereof has been left out, except where necessary. The fiftieth embodiment is not provided with any incoming-talk unit other than the electromagnetic vibrating elements  4326   d ,  4326   e ,  4324   d , and  4324   e , and therefore the phase adjustment mixer unit  36 , a right ear drive unit  4624 , a left ear drive unit  4626 , a reduced air conduction automatic switching unit  4636 , and the electromagnetic vibrating elements  4326   d ,  4326   e ,  4324   d , and  4324   e  (which are illustrated in  FIG. 75 ) constitute the incoming-talk unit in the telephone function unit  45  (which in  FIG. 3  is the incoming-talk unit  13 ). The fiftieth embodiment configured in the manner described above assumes separate embodiments relating to the switch between cartilage conduction and air conduction illustrated in the forty-ninth embodiment, the switch being performed both electrically and automatically. The following description focuses on this point. 
     As described in  FIG. 72E  as well, the fiftieth embodiment of  FIG. 75  assumes a configuration in which cartilage conduction is respectively generated from a plurality of different electromagnetic vibrating elements  4326   e ,  4326   d ,  4324   e , and  4324   d , to the side surface and the front surface. The pair of electromagnetic vibrating elements  4326   d  and  4326   e , which are embedded in the elastic body unit  4363   a , are controlled by the left ear drive unit  4262 , and the pair of electromagnetic vibrating elements  4324   d  and  4324   e , which are embedded in the elastic body unit  4363   b , are controlled by the right ear drive unit  4264 . In such a configuration, similarly with respect to the first embodiment, the acceleration sensor  49  is used to detect which of the elastic body unit  4363   a  and the elastic body unit  4363   b  is in a state of being brought up against an ear, where either the right ear drive unit  4624  or the left ear drive unit  4626  is turned on and the other is turned off. In addition, either the pair of electromagnetic vibrating elements  4326   d  and  4326   e  or the pair of electromagnetic vibrating elements  4324   d  and  4324   e  is rendered able to vibrate and the other is rendered unable to vibrate. 
     The fiftieth embodiment of  FIG. 75  is further provided with an environment-noise microphone  4638  for differentiating between whether or not the environment is quiet. When the noise detected by the environment-noise microphone  4638  is at or above a predetermined level, the reduced air conduction automatic switching unit  4636  functions according to a command from the controller  39  and causes the pair of electromagnetic vibrating elements  4326   d  and  4326   e  or the pair of electromagnetic vibrating elements  4324   d  and  4324   e  to vibrate. On the other hand, in a quiet situation, which is determined by the controller  39  when the noise detected by the environment-noise microphone  4638  is at or below a predetermined level, only the electromagnetic vibrating element  4326   d  or the only the electromagnetic vibrating element  4324   d  is made to vibrate, according to the function of the reduced air conduction switching unit  4636 , and the vibration of the electromagnetic vibrating elements  4326   e  and  4324   e  is stopped. However, for the purpose of detecting the magnitude of environment noise, instead of there being separately provided a dedicated environment-noise microphone  4638  such as in  FIG. 75 , the microphone output in the outgoing-talk unit  23  of the telephone function unit  45  may be used to extract the noise component. The extracting can be performed by analyzing the frequency spectrum of the microphone output, utilizing the microphone output from when audio is interrupted, or the like. 
     The following is a description of the significance of the configuration described above. As illustrated in  FIG. 72E  as well, the vibration direction of the electromagnetic vibrating elements  4326   d  and  4324   d  in the fiftieth embodiment of  FIG. 75  is the direction perpendicular to the side surface, and the vibration direction of the electromagnetic vibrating elements  4326   e  and  4324   e  is the direction perpendicular to the front surface. Because the electromagnetic vibrating elements  4326   e  and  4324   e  vibrate in the direction perpendicular to the front surface on which the display unit  5  or the like is arranged, the entire front surface, which in the mobile telephone  4601  has a large surface area, resonates and has a larger vibration component than the vibration of the side surface from the electromagnetic vibrating elements  4326   d  and  4324   d . For this reason, and with respect to the forty-ninth embodiment, the case in which the pair of electromagnetic vibrating elements  4326   e  and  4326   d  vibrate or the case in which the pair of electromagnetic vibrating elements  4324   e  and  4324   d  vibrate corresponds to the “case of cartilage conduction plus air conduction.” On the other hand, the case in which only the electromagnetic vibrating element  4326   d  vibrates or the case in which only the electromagnetic vibrating element  4324   d  vibrates corresponds to the “case of cartilage conduction only.” However, a certain amount of an air conduction component remains in the “case of cartilage conduction only,” as has been described in the forty-ninth embodiment, and therefore the distinction between these cases is based on a strictly relative comparison of the size of the air conduction component. 
     As has been described above, in a case in which the electromagnetic vibrating elements  4326   e  and  4326   d  vibrate or in a case in which the electromagnetic resonators  4324   e  and  4324   d  vibrate, the user can bring the elastic body unit  4263   a  or  4263   b  against the ear to listen to sound by cartilage conduction, and can also bring any desired portion of the front surface of the mobile telephone  4601  close to or up against the ear to listen to sound by air conduction. Thus, a variety of uses become possible in accordance with the user&#39;s preferences and status. On the other hand, in a case in which only the electromagnetic vibrating element  4326   d  vibrates or in a case in which only the electromagnetic vibrating element  4324   d  vibrates, because relatively less air conduction is generated and sound leakage by air conduction is prevented, particularly in the state in which the environment is quiet, it is possible to listen to sound by cartilage conduction while preventing any disturbance to the surroundings or leakage of sensitive information. In the fiftieth embodiment, air conduction is automatically reduced in a state in which the environment is quiet, due to the functions of the environment-noise microphone  4638  and the reduced air conduction automatic switching unit  4636 . 
     Although the fiftieth embodiment of  FIG. 75  is configured using electromagnetic vibrating elements, the configuration for electrically and automatically switching between cartilage conduction and air conduction is not limited to the case in which the electromagnetic vibrating elements are used as cartilage conduction vibration sources. For example, as in the forty-fifth embodiment of  FIG. 68 , in a case in which a plurality of independently controllable piezoelectric bimorph elements are provided to mutually different directions, the same can be automatically controlled in conformity with the fiftieth embodiment. Another possible configuration in the fiftieth embodiment of  FIG. 75  is one in which a transparent resonance chamber  4563  for generating air conduction is provided, such as in the forty-ninth embodiment of  FIG. 74 , and one or both of the electromagnetic vibrating element  4326   e  and the electromagnetic vibrating element  4324   e  is brought into constant contact with such a transparent resonance chamber  4563 , whereby air conduction is actively generated from the front surface of the mobile telephone  4601 . 
     The various features of the embodiments described above are not limited to implementation in the aforedescribed embodiments, and may be implemented in other aspects as well, provided that the advantages thereof can be enjoyed by doing so. Moreover, the various features of the embodiments are not limited to implementation in their individual embodiments, and combinations which incorporate features of other embodiments, as appropriate, are acceptable. For example, in the present invention, ear-contacting units for cartilage conduction are provided to the corner parts of the mobile telephone. This feature will now be considered, for example, for the mobile telephone  301  configured as a smartphone as in the fourth embodiment of  FIG. 7  (which hereinafter is referred to as the smartphone  301 , for the sake of simplicity). The smartphone  301  as in  FIG. 7  has a large-screen display unit  205  provided with GUI functions on the front surface thereof, and assumes an arrangement in which an ordinary incoming-talk unit  13  is relegated to the upper angled region of the smartphone  301 . Moreover, since the ordinary incoming-talk unit  13  is provided to the middle portion of the part of the smartphone  301 , there is assumed an arrangement in which it is difficult to bring the large-screen display unit  205  up against the cheek bone and to bring the incoming-talk unit  13  close to the ear in a case in which the smartphone  301  is brought up against the ear; and pressing the ordinary incoming-talk unit  13  strongly against the ear so that the voice of the other party can be better heard incurs a result where the large-screen display unit  205  is in contact with the ear or cheek and is fouled by sebum or the like. By contrast, when the right ear vibration unit  224  and the left ear vibration unit  226  are arranged at the corner parts of the smartphone  301  in  FIG. 7 , as is illustrated in  FIG. 2  which relates to the first embodiment, the corner parts of the smartphone  301  are accommodated in the recess around the entrance to the external auditory meatus in the vicinity of the tragus  32 . It thereby becomes possible to readily push the audio output unit of the smartphone  301  against the area around the entrance to the external auditory meatus, and contact made by the large-screen display unit  205  with the ear or cheek can be naturally avoided even in a case of strong pushing. Such an arrangement of the audio output unit at the corner part of the mobile telephone is not limited to the case of using cartilage conduction, and is useful also in a case of an incoming-talk unit that uses an ordinary air conduction speaker. In such a case, air conduction speakers for right ear use and left ear use are preferably provided to the two corners of the upper part of the smartphone. 
     As has already been described, cartilage conduction conducts differently depending on the amount of force pushing on the cartilage, and a state of effective conduction can be obtained by increasing the amount of force that is pushing. This means that when it is difficult to hear the incoming sound, a natural behavior such as increasing the force pushing the mobile telephone against the ear can be utilized to adjust the volume. Furthermore, when the amount of pushing force is increased until a state in which the hole of the ear is obstructed, the volume is further increased due to the earplug bone conduction effect. Even when such a function is not explained to the user in, for example, the instruction manual, the user can still intuitively understand the function through natural behavior. Such an advantage in terms of usage can also be achieved in an artificial sense in a case of an incoming-talk unit in which an ordinary air conduction speaker is used, without the cartilage conduction vibration unit being used as the audio output unit, and can serve as a useful feature of the mobile telephone. 
     Fifty-First Embodiment 
       FIG. 76  is a block diagram relating to a fifty-first embodiment according to an aspect of the present invention, and is configured as a mobile telephone  4701 . The fifty-first embodiment does not utilize a cartilage conduction vibration unit as the audio output unit as described above but rather uses an ordinary air conduction speaker, and is configured such that automatic volume adjustment can be artificially achieved by a natural behavior. In terms of the need to describe the arrangement of the outer appearance, a composite schematic view of the mobile telephone is illustrated in the block diagram. The majority of the block diagram of  FIG. 76  is consistent with the first embodiment of  FIG. 3 , and the majority of the general overview is consistent with the fourth embodiment of  FIG. 7 ; therefore, portions in common have been given like reference numerals, and a description thereof has been left out except where necessary. A volume/acoustics automatic adjustment unit  4736 , a right ear drive unit  4724 , a left ear drive unit  4726 , a right ear air conduction speaker  4724   a , and a left ear air conduction speaker  4726   a  illustrated in  FIG. 76  constitute the incoming-talk unit in the telephone function unit  45  (which in  FIG. 3  is the outgoing-talk unit  13 ). 
     The right ear air conduction speaker  4724   a  of the fifty-first embodiment in  FIG. 76  is controlled by the right ear drive unit  4524 , and the left ear air conduction speaker  4726   a  is controlled by the right ear drive unit  4526 . Also, similarly with respect to the fiftieth embodiment, the acceleration sensor  49  is used to detect which of the right ear air conduction speaker  4724   a  and the left ear air conduction speaker  4726   a  is in a state of being brought up against an ear, where either the right ear drive unit  4524  or the left ear drive unit  4526  is turned on and the other is turned off. In addition, either the right ear air conduction speaker  4724   a  or the left ear air conduction speaker  4726   a  is turned on and the other is turned off. 
     A right ear pressure sensor  4742   a  and a left ear pressure sensor  4742   b  are respectively provided to the vicinity of the right ear air conduction speaker  4724   a  and the left ear air conduction speaker  4726   a  and detect pressure on whichever of the right ear air conduction speaker  4724   a  or left ear air conduction speaker  4726   a  is turned on. A left/right pressure sensor processing unit  4742  analyzes the magnitude of the detected pressure and sends volume/acoustics control data to the controller  39 . The controller  39  commands a volume/acoustics automatic adjustment unit  4736  on the basis of the volume/acoustics control data and automatically adjusts the volume of whichever of the right ear drive unit  4524  or left ear drive unit  4526  is on. The volume is basically adjusted such that the volume increases with an increase in pressure and, when it is difficult to listen to the incoming-talk unit sound, is set so as to be a suitable response to a natural behavior such as increasing the force pushing the mobile telephone  4701  against the ear. 
     A supplementary detailed description of the function of the volume/acoustics automatic adjustment unit  4736  will now be provided. To avoid unstable volume changes due to changes in pressure, first, volume changes are configured such that the volume only undergoes stepwise changes in the increasing direction and in accordance only with an increase in pressure. Furthermore, to avoid unintentional volume changes, the volume/acoustics automatic adjustment unit  4736  is configured such that volume increases in a stepwise manner in reaction only to when a predetermined pressure increase lasts on average for a predetermined period of time (for example, 0.5 seconds) or longer. The volume/acoustics automatic adjustment unit  4736  is also configured such that volume is instantaneously lowered to a baseline state in a case in which it is detected that the state in which the pressure has fallen to a predetermined value (corresponding to the state in which whichever of the right ear air conduction speaker  4724   a  or left ear air conduction speaker  4726   a  is turned on is brought away from the ear) or lower has lasted for a predetermined period of time (for example, 1 second) or longer. The user is thereby able to intentionally bring the mobile telephone  4701  slightly away from the ear in a case in which the volume has been excessively increased or the like (which is also consistent with a natural operation such as bringing a sound source away from the ear when the sound is too loud), and once the volume has been reset to the baseline state, the force of the pressure is again increased to achieve a desired volume. 
     The volume/acoustics automatic adjustment unit  4736  is further able to automatically adjust the acoustics. This function is related to the environment-noise microphone  38  described in relation to the first embodiment in  FIG. 3 . Namely, in the first embodiment, the environment noise picked up by the environment-noise microphone  38 , is mixed into the right-ear cartilage-conduction vibration unit  24  and the left-ear cartilage-conduction vibration unit  26  upon undergoing wavelength inversion; the environment noise, which is contained in the audio information through the incoming-talk unit  13 , is canceled and the audio information of the party on the line becomes easier to comprehend through listening. The volume/acoustics automatic adjustment unit  4736  in the fifty-first embodiment utilizes this function to turn the noise-canceling function off when the pressure is equal to or less than a predetermined value and to turn the noise-canceling function on when the pressure is equal to or above a predetermined value. The degree to which the environment noise inversion signal is mixed can also be adjusted in a stepwise manner, whereby the noise-canceling function, rather than merely being turned on and off, can also undergo continuous or stepwise increases and decreases. Thus, the volume/acoustics automatic adjustment unit  4736  is capable of automatically adjusting not only the volume but also the acoustics, on the basis of the output of the left/right pressure sensor processing unit  4742 . The fifty-first embodiment of  FIG. 76  is an embodiment that serves to illustrate that the aforementioned advantage, in which the right ear audio output unit and the left ear audio output unit are arranged at the corner parts of the smartphone, is not limited to a case in which cartilage conduction is used; benefits may also accrue therefrom in a case in which an outgoing-talk unit using ordinary air conduction speakers is utilized. 
     The various features of the embodiments described above are not limited to implementation in the aforedescribed embodiments, and may be implemented in other aspects as well, provided that the advantages thereof can be enjoyed by doing so. Moreover, the various features of the embodiments are not limited to implementation in their individual embodiments, and combinations which incorporate features of other embodiments, as appropriate, are acceptable. The various features of each of the embodiments described above are not to be limited to the above embodiments; rather, wherever it is possible to benefit from the feature of an embodiment, the same can also be implemented in other embodiments. The various features of each of the embodiments are not to be restricted to individual respective embodiments, but rather can be substituted or combined with other appropriate embodiments. For example, in the fifty-first embodiment of  FIG. 76 , a determination is made as to which of the right ear air conduction speaker  4724   a  or left ear air conduction speaker  4726   a  is to be turned on according to the output of the acceleration sensor  49 , but the configuration may be such that the outputs of the right ear pressure sensor  4742   a  and left ear pressure sensor  4742   b  are used to turn on whichever of the right ear air conduction speaker  4724   a  or left ear air conduction speaker  4726   a  has more pressure, and to turn the other off. 
     Also, the fifty-first embodiment of  FIG. 76  is provided with the right ear air conduction speaker  4724   a  and the left ear air conduction speaker  4726   a  as well as the right ear pressure sensor  4742   a  and left ear pressure sensor  4742   b  corresponding thereto, but when there is only the purpose of automatic volume/acoustics adjustment by pressure, then a single conventional air conduction speaker may be provided to the middle of the upper part of the mobile telephone, and a single pressure sensor may be provided correspondingly with respect thereto. Furthermore, the fifty-first embodiment of  FIG. 76  has illustrated how environment noise is canceled out by waveform inversion as a fundamental configuration of the automatic adjustment of acoustics by the volume/acoustics automatic adjustment unit  4736 , but such a configuration is not provided by way of limitation. For example, the configuration may be such that the volume/acoustics automatic adjustment unit  4736  is provided with a filter for cutting out environment noise (for example, a low-frequency-band-cutting filter), the filter being turned off when the pressure is at or below a predetermined value and the filter function being turned on when the pressure is at or above a predetermined value. The configuration may also be such that, instead of a low-frequency band or the like being cut out by the filter, the gain of the low-frequency band is dropped (or the gain of a high frequency area is raised). The filter function or the frequency-band-selective gain function can also be adjusted in a stepwise manner, whereby the filter function or the frequency-selective gain function, rather than merely being turned on and off, can also alter the environment noise reduction capability in a stepwise or continuous manner in accordance with the pressure. 
     MODES FOR CARRYING OUT THE INVENTION 
     Fifty-Second Embodiment 
       FIG. 77  is a cross-sectional view relating to a fifty-second embodiment according to an aspect of the present invention, and is configured as a mobile telephone  4801 .  FIG. 77  provides a cross-sectional view of the mobile telephone  4801 , depicted in order to describe the support structure and arrangement of piezoelectric bimorph elements  2525   a  and  2525   b  serving as cartilage conduction vibration sources, while the interior of the cross-sectional view, which relates to the control of the mobile telephone, depicts not an actual arrangement but rather a block diagram. The block diagram portion, being founded on the block diagram of the first embodiment illustrated in  FIG. 3 , essentially omits a depiction of shared portions, with the exception of those needed to understand the interrelationships, and like portions, when depicted, have been assigned like reference numerals, a description thereof being omitted unless needed. 
     The fifty-second embodiment of  FIG. 77 , similarly with respect to the forty-ninth embodiment of  FIG. 74  and the fiftieth embodiment of  FIG. 75 , is configured as an embodiment permitting the interchange of “the case of cartilage conduction plus air conduction” and “the case of cartilage conduction only. “Further, the fifty-second embodiment of  FIG. 77 , similarly with respect to the forty-sixth embodiment of  FIG. 69 , has elastic body units  4863   a ,  4863   b ,  4863   c , and  4863   d  serving as protectors provided to the four corners susceptible to impact when the mobile telephone  4801  is accidentally dropped. However, rather than a two-sided support structure for the elastic body units  4863   a ,  4863   b  to support the piezoelectric bimorph elements  2525   a  and  2525   b , a single side thereof is supported on a cantilever structure, similarly with respect to the forty-second embodiment of  FIG. 65  and the forty-third embodiment of  FIG. 66 . As above, the fifty-second embodiment of  FIG. 77  is related to features of various embodiments having already been described, wherefore a repetitive description of the individual features has been avoided unless needed, since the same are readily understood from the descriptions of the corresponding embodiments. 
     First, the structure and arrangement of the fifty-second embodiment of  FIG. 77  will now be described. As has already been mentioned, the four corners of the mobile telephone  4801  are provided with the elastic body units  4863   a ,  4863   b ,  4863   c , and  4863   d , serving as protectors. The outer sides of the corners of such elastic members are beveled in a smooth convex shape to prevent the occurrence of slight pain when held against the ear cartilage. Although a more detailed description will also be provided later, the shape of the corner parts allows for a suitable fit with the cartilage around the external auditory meatus and for comfortable listening by cartilage conduction. 
     In the fifty-second embodiment of  FIG. 77 , the piezoelectric bimorph element  2525   b  for the right ear and the piezoelectric bimorph element  2525   a  for the left ear are employed as described above, and can be controlled separately, similarly with respect to the first embodiment illustrated in  FIGS. 1 to 4 . The piezoelectric bimorph elements  2525   b  and  2525   a  are appropriately long enough to obtain suitable frequency output properties, but in order for both to be compactly arranged within the mobile telephone  4801 , the piezoelectric bimorph element  2525   b  for the right ear, as illustrated in  FIG. 77 , is laid horizontally, the end to which no terminal is provided being supported by the elastic body unit  4863   b . On the other hand, the piezoelectric bimorph element  2525   a  for the left ear is stood upright, the end to which no terminal is provided being supported by the elastic body unit  4863   a  (however, the vertical and horizontal arrangement of the piezoelectric bimorph elements for the right ear and for the left ear may be inverted from the description above). A terminal is provided to the other ends of each of the piezoelectric bimorph elements  2525   b  and  2525   a , but serves as a free end in terms of the support structure due to the connection thereof with the controller  39  by a flexible lead. Thus, the vibration of the free ends of the piezoelectric bimorph elements  2525   b  and  2525   a  exhibits opposite actions on the elastic body unit  4863   b  and the elastic body  4863   a , and cartilage conduction can be obtained by bringing the same into contact with the ear cartilage. The primary vibration direction of the piezoelectric bimorph elements  2525   b  and  2525   a  is the direction perpendicular to the plan in  FIG. 77 . 
     Next, the manner in which the piezoelectric bimorph elements  2525   b  and  2525   a  are controlled will be described. The piezoelectric bimorph element  2525   b  for the right ear, which is supported by the elastic body unit  4863   b , is driven by a right ear amplifier  4824  via a switch  4824   a . On the other hand, the piezoelectric bimorph element  2525   a  for the left ear, which is supported by the elastic body unit  4863   a , is driven by a left ear amplifier  4826  via a switch  4826   a . An audio signal from the phase adjustment mixer unit  36  is inputted into the right ear amplifier  4824  and the left ear amplifier  4826 ; the audio signal to the left ear amplifier  4826  is phase-inverted by a waveform inverter  4836   b  and then inputted via a switch  4836   a . As a result, in the state depicted in  FIG. 77 , vibrations having mutually inverted phases are conducted to and mutually canceled out in the chassis of the mobile telephone  4801  from the elastic body unit  4863   a  and the elastic body unit  4863   b , and the generation of air conduction sound from the entire surface of the chassis of the mobile telephone  4801  is substantially eliminated. 
     In a case where, for example, the cartilage of the right ear is brought into contact with the elastic body unit  4863   b , there will be direct cartilage conduction to the ear cartilage from the elastic body  4863   b , whereas, by contrast, the vibration of the elastic body unit  4863   a  reaches the elastic body unit  4863   b  and is conducted to the ear cartilage as cartilage conduction only after having been first conducted to the chassis of the mobile telephone  4801 . Accordingly, since a difference emerges in the intensities of the phase-inverted vibrations, the difference will be conducted to the ear cartilage as cartilage conduction from the elastic body unit  4863   b  without having been canceled out. The same is also true of a case where the cartilage of the left ear is brought into contact with the elastic body unit  4863   a . Accordingly, the state depicted in  FIG. 77  in the fifty-second embodiment becomes a state corresponding to the “case of cartilage conduction only” in the forty-ninth embodiment of  FIG. 74  and the fiftieth embodiment of  FIG. 75 . An air conduction eliminating gain adjustment unit  4836   c  serves to adjust the gain of the left ear amplifier  4826  so as to cancel out vibration to the chassis of the mobile telephone  4801  from the elastic body unit  4863   a  and the elastic body unit  4863   b  as described above, whereby the generation of air conduction sound will be minimized. Also, rather than being provided to the left ear amplifier  4826  side, the aforesaid switch  4836   a , waveform inverter  4836   b , and air conduction eliminating gain adjustment unit  4836   c  may also be instead provided to the right ear amplifier  4824  side. Alternatively, the air conduction eliminating gain adjustment unit  4836   c  only may be provided to the right ear amplifier  4824  side. 
     The fifty-second embodiment of  FIG. 77  is provided with the environment-noise microphone  4638  for determining whether or not the environment is silent. When the noise detected by the environment-noise microphone  4638  is at or above a predetermined amount, the switch  4836   a  is switched to a signal pathway (the lower one in  FIG. 77 ) by a command from the controller  39 . An audio signal from the phase adjustment mixer unit  36  is thereby conducted to the left ear amplifier  4826  without waveform inversion. At such a time, the vibration conducted to the chassis of the mobile telephone  4801  from the elastic body unit  4863   a  and the elastic body unit  4863   b  is not canceled out, but rather air conduction sound from the entire surface of the chassis of the mobile telephone  4801  is conversely generated at a two-fold increase. Such a state serves as a state corresponding to the “case of cartilage conduction plus air conduction” in the forty-ninth embodiment of  FIG. 74  and the fiftieth embodiment of  FIG. 75 . Because of the two-fold increase in air conduction sound from the entire surface of the chassis, such a state is suitable for a case where the mobile telephone  4801  is taken away from the ear and audio is listened to, as is done during a videoconferencing function or similar circumstances; in the case of the videoconferencing function mode, the switch  4836   a  is switched to the signal pathway (the lower one in  FIG. 77 ) by a command from the controller  39  irrespective of the detection of the environment-noise microphone  4638 . 
     In circumstances determined to be silent by the controller  39  when the noise detected by the environment-noise microphone  4638  is at or below a predetermined amount, the switch  4836   a  is switched to the state depicted in  FIG. 77  by a command from the controller  39 . As described above, the vibrations conducted to the chassis of the mobile telephone  4801  from the elastic body unit  4863   a  and the elastic body unit  4863   b  are thereby mutually canceled out, substantially eliminating the generation of air conduction sound, which serves as a state corresponding to the “case of cartilage conduction only.” 
     Further, similarly with respect to the first embodiment, it is possible in the fifty-second embodiment of  FIG. 77  for the state of whether the elastic body unit  4863   a  or the elastic body unit  4863   b  has been brought up against the ear to be detected by an acceleration sensor  49 , and for the switch  4824   a  and a switch  4826   a  to be controlled by the control of the controller  39 . Then, the operation unit  9  can be used to switch between a two-sided always-on mode in which both the switch  4824   a  and the switch  4826   a  are on irrespective of the state detected by the acceleration sensor  49 , and a one-sided on mode in which one of either the switch  4824   a  or the switch  4826   a  is turned on and the other is turned off on the basis of the state detected by the acceleration sensor  49 . In the one-sided on mode, for example, the switch  4824   a  is turned on and the switch  4826   a  is turned off when the right ear is brought up against the elastic body unit  4863   b . The inverse occurs when the left ear is brought up against the elastic body unit  4863   a.    
     The one-sided on mode further incorporates the function of the environment-noise microphone  4638 ; when the environmental noise detected by the environment-noise microphone  4638  is at or above a predetermined amount, one of either the switch  4824   a  or the switch  4826   a  is turned on and the other is turned off on the basis of the state detected by the acceleration sensor  49 . In circumstances determined to be silent by the controller  39  when the noise detected by the environment-noise microphone  4638  is at or below a predetermined amount, both the switch  4824   a  and the switch  4826   a  are turned on by a command from the controller  39  irrespective of the state detected by the acceleration sensor  49 , the switch  4836   a  being switched to the state depicted in  FIG. 77 , and the vibrations conducted to the chassis of the mobile telephone  4801  from the elastic body unit  4863   a  and the elastic body unit  4863   b  are thus mutually canceled out. 
       FIG. 78  is a perspective view and cross-sectional views relating to the fifty-second embodiment of  FIG. 77 .  FIG. 78A  is a perspective view in which the mobile telephone  4801  of the fifty-second embodiment is seen from the front surface, and illustrates the manner in which the outer surfaces of the corners of the elastic body units  4863   a ,  4863   b ,  4863   c , and  4863   d  provided as protectors to the four corners of the mobile telephone  4801  are beveled so as to have a smooth, convex shape. As described above, such an outer surface shape of the corner parts of the mobile telephone  4801  prevents the occurrence of slight pain when the elastic member  4863   a  or  4863   b  is brought up against the ear cartilage, and also allows for the corner parts of the mobile telephone  4801  to be suitably fitted to the cartilage around the entrance part of the external auditory meatus inside the auricle, permitting comfortable listening by cartilage conduction. The occlusion of the entrance part of the external auditory meatus by the beveled corner parts produces the earplug bone conduction effect, which intensifies the audio signal from the mobile telephone  4801  in the external auditory meatus and also makes it easier to listen to the audio signal in the presence of noise, due to the noise of the external environment being blocked by the occlusion of the entrance part of the external auditory meatus. 
       FIG. 78B  is a cross-sectional view cutting through the mobile telephone  4801  on the B 1 -B 1  cross-sectional plane of  FIG. 78A , on the plane perpendicular to the front view and side view;  FIG. 78C  is a cross-sectional view cutting through the mobile telephone  4801  on the B 2 -B 2  cross-sectional plane illustrated in  FIG. 78A or 78B , on the plane perpendicular to the plan view and the top view. The manner in which the outer surfaces of the corners of the elastic body units  4863   a ,  4863   b ,  4863   c , and  4863   d  are beveled so as to have a smooth, convex shape will be readily understood from either of  FIG. 78B or 78C . As illustrated by the arrow  25   g  in  FIGS. 78B and 78C , the primary vibration direction of the piezoelectric bimorph element  2525   b  is the direction perpendicular to the display surface of the GUI display unit  3405 . Further, as illustrated by the arrow  25   m  in  FIG. 78B , the primary vibration direction of the piezoelectric bimorph element  2525   a  is the direction perpendicular to the display surface of the GUI display unit  3405 . 
     Although each of the switches  4824   a ,  4826   a , and  4836   a  in the fifty-second embodiment are symbolically depicted in  FIG. 77  as mechanical switches, in practice the same are preferably constituted of electrical switches. Also, except in the case of switching between the two-sided always-on mode and the one-sided on mode, the switches in the fifty-second embodiment have been depicted by way of the example of automatically switching on the basis of the results detected by the acceleration sensor  49  and/or the environment-noise microphone  4638 , but the configuration may also permit manual switching as desired, by the operation unit  9 . It is also possible to omit the switches, as appropriate. For example, when the fifty-second embodiment is simplified so as to always be in the connection state depicted in  FIG. 77 , a mobile telephone is obtained in which the generation of air conduction sound from the entire surface of the chassis is substantially eliminated and cartilage conduction occurs when the elastic body unit  4863   a  or the elastic body unit  4863   b  is brought into contact with the ear cartilage. 
     The various features of each embodiment described above are not to be restricted to individual respective embodiments, but rather can be substituted or combined with other appropriate embodiments. For example, although the fifty-second embodiment of  FIGS. 77 and 78  employs the piezoelectric bimorph elements as cartilage conduction vibration sources, the cartilage conduction vibration sources may be substituted for other vibrators, such as with the magnetic vibrators in the forty-eighth embodiment of  FIGS. 72 and 73 , the fiftieth embodiment of  FIG. 75 , or the fifty-first embodiment of  FIG. 76 . 
       FIG. 79  is a graph illustrating an example of measurement data of the mobile telephone configured on the basis of the forty-sixth embodiment of  FIG. 69 . In the graph of  FIG. 79 , the mobile telephone  4201  of the forty-sixth embodiment (in which configuration the vibration from the vibration source inside the outer wall is transmitted to the surface of the outer wall) is used to illustrate, in relation to the frequency, the sound pressure within the external auditory meatus 1 cm from the entrance part of the external auditory meatus when, without contact with the auricular helix, the surface of the outer wall of the corner parts of the mobile telephone  4201  is brought into contact with at least a part of the ear cartilage around the entrance part of the external auditory meatus, according to  FIGS. 2A and 2B , which have been used to describe the first embodiment. In the graph, the vertical axis is the sound pressure (in dBSPLs), and the horizontal axis is the frequency on a logarithmic scale (in Hz). In terms of the contact pressure relationship between the surface of the outer wall of the corner parts of the mobile telephone  4201  and the cartilage around the entrance part of the external auditory meatus, the graph uses a solid line to illustrate the sound pressure during a non-contact state, a short-dashed line to illustrate the sound pressure in a state of slight contact (10 grams of contact pressure), a single-dotted line to illustrate the sound pressure in a state in which the mobile  4201  is being used normally (250 grams of contact pressure), and a double-dotted line to illustrate the sound pressure in a state in which the external auditory meatus is occluded by increased contact pressure (500 grams of contact pressure). As illustrated, the sound pressure increases from the non-contact state due to contact of 10 grams of contact pressure and increases further due to the contact pressure increasing to 250 grams; the sound pressure increases even more when the contact pressure is increased further from such a state to 500 grams. 
     It will be readily understood from the graph of  FIG. 79  that when the surface of the outer wall of the mobile telephone  4201 , which has the vibration source arranged inward from the surface of the outer wall and is configured such that the vibration of the vibration source is transmitted to the surface of the outer wall, is brought into contact with at least a part of the ear cartilage around the entrance part of the external auditory meatus without making contact with the auricular helix, the sound pressure in the external auditory meatus about 1 cm from the entrance part of the external auditory meatus has an increase of at least 10 dB in the main frequency range of speech (500 Hz to 2,300 Hz), compared to the non-contact state (to be contrasted with the non-contact state illustrated by the solid line and the state in which the mobile telephone  4201  is being used normally, illustrated by the single-dotted line). 
     It will also be readily understood from the graph of  FIG. 79  that when the surface of the outer wall of the mobile telephone  4201  is brought into contact with at least a part of the ear cartilage around the entrance part of the external auditory meatus without making contact with the auricular helix, the sound pressure in the external auditory meatus about 1 cm from the entrance part of the external auditory meatus has an at least 5 dB change in the main frequency range of speech (500 Hz to 2,500 Hz) according to the change in contact pressure (to be contrasted with the slight contact state illustrated by the short-dashed line and the contact state in the state in which the mobile telephone  4201  is being used normally, illustrated by the single-dotted line). 
     It will further be readily understood from the graph of  FIG. 79  that when the entrance part of the external auditory meatus is occluded by the surface of the outer wall of the mobile telephone  4201  being brought into contact with at least a part of the ear cartilage around the entrance part of the external auditory meatus without making contact with the auricular helix (for example, when the surface of the outer wall of the mobile telephone  4201  is strongly pressed against the outside of the tragus, thus folding the tragus over and occluding the external auditory meatus), the sound pressure in the external auditory meatus about 1 cm from the entrance part of the external auditory meatus has an increase of at least 20 dB in the main frequency range of speech (300 Hz to 1,800 Hz) compared to the non-contact state (to be contrasted with the non-contact state illustrated by the solid line and the state in which the external auditory meatus is occluded, illustrated by the double-dotted line). 
     The measurements in  FIG. 79  are all in a state in which the output of the vibration source does not change. The measurements in  FIG. 79  for the state where the surface of the outer wall is brought into contact with at least a part of the ear cartilage around the external auditory meatus without making contact with the auricular helix are performed in a state where the surface of the outer wall was in contact from the outside of the tragus. The measurements in  FIG. 79  made in a state of the external auditory meatus being occluded were performed by creating a state where the external auditory meatus was occluded by the tragus being folded due to being more strongly pressed against from the outside, as described above. 
     As described above, the measurements in  FIG. 79  were performed in a state where the surface at the corner parts of the outer wall in the mobile telephone  4201  of the forty-sixth embodiment illustrated in  FIG. 69  was brought into contact with the outside of the tragus, but the corner parts of the forty-sixth embodiment serve as the elastic body units  4263   a ,  4263   b  acting as protectors, and are constituted of a material different from the other portions of the outer wall. The vibration source is supported on the inner surface of the corner parts of the outer wall constituted of the elastic body units  4263   a ,  4263   b . The corner parts of the outer wall of the mobile telephone  4201  are susceptible to impact from the outside, and are firmly bonded to prevent the occurrence of relative deviation between the outer wall and the other portions even in a case of being constituted of the elastic body units  4263   a ,  4263   b.    
     The measurement graph of  FIG. 79  is merely an example; upon further scrutiny, there are individual differences. Also, the measurement graph of  FIG. 79  was measured in a state where the surface of the outer wall was brought into contact only with a small surface area of the outside of the tragus, for the sake of simplifying and standardizing the phenomenon. However, an increase in sound pressure due to contact also relies on the area of contact with the cartilage, and in a case where the surface of the outer wall is brought into contact with the ear cartilage around the entrance part of the external auditory meatus without making contact with the auricular helix, the increase in sound pressure is elevated further when there is contact with a portion of the cartilage wider than around the entrance part of the external auditory meatus. In consideration of the facts above, the values illustrated in the measurement graph of  FIG. 79  have a certain universality in illustrating the configuration of the mobile telephone  4201 , and can be reproduced by a non-specific number of test subjects. Further, the measurement graph of  FIG. 79  was achieved by the tragus being pressed from the outside when the entrance part of the external auditory meatus is occluded, thus increasing the contact pressure and folding the tragus over, but similar results are also obtained in a case where the corner parts of the mobile telephone  4201  are pressed on the entrance part of the external auditory meatus, which is then occluded. The measurements in  FIG. 79  were measured by the vibration source being held on the inside of the corner parts of the outer wall, as in the mobile telephone  4201  of the forty-sixth embodiment of  FIG. 69 , but there is no limitation thereto, and the measurements are also reproducible in other embodiments as well. For example, the measurements are also reproducible with a configuration in which the vibration source is held on the interior of the elastic body units  4363   a ,  4363   b  serving as protectors, as illustrated in  FIG. 72  (for example, an embedded configuration). 
     In other words, the measurement graph of  FIG. 79  suffices to explain the characteristic of the mobile telephone of the present invention, in that when the surface of the outer wall of the mobile telephone, which has the vibration source arranged inward from the surface of the outer wall and is configured such that the vibration of the vibration source is transmitted to the surface of the outer wall, is brought into contact with at least a part of the ear cartilage around the entrance part of the external auditory meatus without making contact with the auricular helix, the sound pressure inside the external auditory meatus about 1 cm from the entrance part of the external auditory meatus has an at least 10 dB increase in at least a part (for example, 1,000 Hz) of the main frequency range of speech (500 Hz to 2,300 Hz), compared to the non-contact state. 
     The graph in  FIG. 79  also suffices to explain the characteristic of the mobile telephone of the present invention, in that when the surface of the outer wall of the mobile telephone is brought into contact with at least a part of the ear cartilage around the entrance part of the external auditory meatus without making contact with the auricular helix, the sound pressure inside the external auditory meatus about 1 cm from the entrance part of the external auditory meatus has an at least 5 dB increase in at least a part (for example, 1,000 Hz) of the main frequency range of speech (500 Hz to 2,500 Hz) due to the increase in contact pressure. 
     The graph in  FIG. 79  further suffices to explain the characteristic of the mobile telephone of the present invention, in that when the entrance part of the external auditory meatus is occluded by the surface of the outer wall of the mobile telephone  4201  being brought into contact with at least a part of the ear cartilage around the entrance part of the external auditory meatus without making contact with the auricular helix, the sound pressure in the external auditory meatus about 1 cm from the entrance part of the external auditory meatus has an increase of at least 20 dB in at least a part (for example, 1,000 Hz) of the main frequency range of speech (300 Hz to 1,800 Hz) compared to the non-contact state. 
     The mobile telephone of the present invention as confirmed by the measurements in the graph of  FIG. 79  is significant in the following manner. Namely, the present invention provides a mobile telephone having a vibration source arranged inward from the surface of an outer wall, and volume adjustment means, the vibration of the vibration source being transmitted to the surface of the outer wall, and sound being listened to by bringing the surface of the outer wall into contact with at least a part of the ear cartilage around the entrance part of the external auditory meatus without making contact with the auricular helix; the features thereof are defined as follows. Namely, in a room where the noise level (the A-weighted sound pressure level) is 45 dB or less, the mobile telephone being brought into proximity with the entrance part of the external auditory meatus and the surface of the outer wall being arranged so as to not be in contact, the volume is minimized and pure sound at 1,000 Hz is generated from the vibration source. In addition, narrow-band noise at 1,000 Hz (⅓ octave-band noise) at a marginal level where the pure sound at 1,000 Hz is masked and cannot be heard is generated from a loudspeaker at a position separated from the entrance part of the external auditory meatus by 1 m. This can be confirmed by sequentially increasing narrow-band noise at 1,000 Hz and determining the magnitude at which pure sound at 1,000 Hz is masked and can no longer be heard. The narrow-band noise at 1,000 Hz is subsequently increased by 10 dB from the marginal level, but according to the mobile telephone of the present invention, bringing the surface of the outer wall into contact with at least a part of the ear cartilage around the entrance part of the external auditory meatus without making contact with the auricular helix makes it possible to listen to pure sound at 1,000 Hz without the need to adjust or change the volume adjusting means. 
     When the narrow-band noise at 1,000 Hz is further increased by 20 dB from the marginal level as determined above, according to the mobile telephone of the present invention, bringing the surface of the outer wall into contact with at least a part of the ear cartilage around the entrance part of the external auditory meatus without making contact with the auricular helix makes it possible to listen to pure sound at 1,000 Hz without the need to adjust or change the volume adjusting means. 
       FIG. 80  is a side view and a cross-sectional view of an ear, intended to illustrate the relationship between the detailed structure of the ear and the mobile telephone of the present invention.  FIG. 80A  is a side view of the left ear  30 , where a position  4201   a  shown with a single-dotted line depicts the state where the corner part of the mobile telephone  4201  is brought into contact with the outside of the tragus. The position  4201   a  corresponds to the state in which the measurements of  FIG. 79  were performed. Meanwhile, a position  4201   b  shown by the double-dotted line is a depiction of the state where the corner part of the mobile telephone  4201  is brought into contact with a portion of cartilage wider than that around the entrance part of the external auditory meatus. At the position  4201   b , an increase in sound pressure greater than what is illustrated in  FIG. 79  can be achieved through the contact with the ear cartilage. 
       FIG. 80B  is a cross-sectional view of the right ear  28 , and depicts the manner in which the vibration of the vibration source generated from the corner part of the mobile telephone  4201  is conducted to the tympanic membrane  28   a . The mobile telephone  4201  in the state in  FIG. 80B  has been brought into contact with a portion of cartilage wider than that around the entrance part of the external auditory meatus, according to the position  4201   b  in  FIG. 80A  (though it may not be evident from the portion of the cross-sectional view alone, the entrance part of the external auditory meatus is not occluded in such a state). A vibration  28   b  generated from the corner part of the mobile telephone  4201  is conducted to the cartilage around the entrance part of the external auditory meatus from the portion of contact, and air conduction sound is subsequently generated in the external auditory meatus  28   c  from the cartilage part external auditory meatus surface. The air conduction sound then proceeds through the inside of the external auditory meatus  28   c  and reaches the tympanic membrane  28   a . Direct air conduction  28   d  is also generated from the corner part of the mobile telephone  4201 , and naturally also proceeds through the inside of the external auditory meatus  28   c  and reaches the tympanic membrane  28   a . In the state where the mobile telephone  4201  is not in contact with the cartilage, solely the direct air conduction  28  reaches the tympanic membrane  28   a.    
     An additional description shall now be provided for the frequency characteristics of the piezoelectric bimorph element  2525  used in the forty-sixth embodiment of  FIG. 69  and elsewhere. The frequency characteristics of the piezoelectric bimorph element  2525  used in embodiments of the present invention in regard to the generation of direct air conduction are not flat; rather, the generation of air conduction at frequencies below substantially approximately 1 kHz is correspondingly less than at frequencies above the boundary. Such a frequency characteristic in the piezoelectric bimorph element  2525  in regard to the generation of direct air conduction is ideally matched to the frequency characteristic in a case where there is air conduction sound from the piezoelectric bimorph element  2525  in the external auditory meatus directly via the cartilage. Namely, the sound pressure in the external auditory meatus according to the frequency characteristics in air conduction sound through cartilage conduction is greater in frequencies below about 1 kHz than frequencies that are higher than this boundary. Therefore, in a case involving the use of the piezoelectric bimorph element  2525  of the frequency characteristic described above for the generation of direct air conduction, the fact that the two are complementary results in the frequency characteristic of sound reaching the tympanic membrane being approximately flat. Thus, the cartilage conduction vibration source used in the present invention exhibits a frequency characteristic for the generation of air conduction sound that trends inversely with respect to the frequency characteristic in cartilage conduction. 
       FIG. 79 , which is the measurement data from the forty-sixth embodiment of  FIG. 69 , provides a specific description of such facts. In the graph of  FIG. 79 , sound pressure is viewed by applying a sine wave with a varying frequency at the same voltage to the piezoelectric bimorph element  2525  having the structure illustrated in  FIG. 69 , wherefore the sound pressure in non-contact illustrated by the solid line in the graph of  FIG. 79  substantially exhibits the frequency characteristic for generating air conduction sound generated from the piezoelectric bimorph element  2525 . In other words, as is clear from the solid line in the graph of  FIG. 79 , the frequency characteristic for generating air conduction sound by the piezoelectric bimorph element  2525  is not flat, but rather, when there is a focus on a band between, for example, 100 Hz and 4 kHz, then the comparative sound pressure is low primarily in the low-frequency band (for example, 200 Hz to 1.5 kHz), and the sound pressure is high primarily in the high-frequency band (for example, 1.5 kHz to 4 kHz) (the sound pressure measured in  FIG. 79  is that in the external auditory meatus at about 1 cm from the entrance part of the external auditory meatus, and therefore the influence of the effect of unoccluded ear gain in increasing sound pressure is observed between 2.5 kHz and 3.5 kHz, but it is clear that the high-frequency band has a relatively higher sound pressure than the low-frequency band even when interpreted with this portion subtracted). Thus, viewed from  FIG. 79  as well, the frequency characteristic of the piezoelectric bimorph element  2525  used in the forty-sixth embodiment of  FIG. 69  and elsewhere is not flat, but rather the generated air conduction sound at low frequencies will be readily understood to be relatively less than that at high frequencies, the boundary being substantially at about 1 kHz. 
     Next, in the graph of the normal state of contact  250   g  shown in  FIG. 79  with a single-dotted line, a marked increase in sound pressure compared to the state of non-contact is observed beginning at a few hundred Hz, closer to the lower-frequency region than to 1 kHz; the increase persists until at least about 2.5 kHz. Accordingly, the frequency characteristic of sound measured in the external auditory meatus for the piezoelectric bimorph element  2525 , which is the same vibration source, exhibits a clear difference between direct air conduction and air conduction through cartilage conduction (that is, air conduction through cartilage conduction has a large increase in sound pressure, particularly at a few hundred Hz to 2.5 kHz, compared to direct air conduction). As a result, as illustrated by the graph of the normal state of contact  250   g  shown in  FIG. 79  by the single-dotted line, as regards the sound pressure in the external auditory meatus in the case of air conduction through cartilage conduction, the frequency characteristic of the sound that reaches the tympanic membrane as a result is closer to being flat than in the case of direct air conduction illustrated by the solid line. 
     Additionally, a state of external auditory meatus occlusion  500   g  illustrated by  FIG. 79  with a double-dotted line has a further pronounced increase in sound pressure between a few hundred Hz to 1 kHz, due to the earplug bone conduction effect, and the piezoelectric bimorph element  2525 , which is the same vibration source, exhibits disparate frequency characteristic clearly different from both the state of normal contact  250   g  and the state of non-contact. However, because unoccluded ear gain ceases to be present in the state of external auditory meatus occlusion  500   g  illustrated with the double-dotted line, presumably there appears a result such that the effect from the peak sound pressure at 2.5 kHz to 3.5 kHz observed in the state of open external auditory meatus has disappeared. 
     Fifty-Third Embodiment 
       FIG. 81  is a block diagram of a fifty-third embodiment according to an aspect of the present invention. The fifty-third embodiment, similarly with respect to the twenty-fifth embodiment of  FIG. 38 , is configured as 3D television viewing eyeglasses  2381  by which stereo audio information can be experienced, and forms a 3D television viewing system together with a 3D television  2301 . Also similarly with respect to the twenty-fifth embodiment, the vibration of a right-ear cartilage-conduction vibration unit  2324  arranged at a right temple unit  2382  is transmitted to the outer side of the cartilage of the base of the right ear via a contact unit  2363 , and the vibration of a left-ear cartilage-conduction vibration unit  2326  arranged at a left temple unit  2384  is transmitted to the outer side of the cartilage of the base of the left ear via a contact unit  2364 . The fifty-third embodiment has much in common with the twenty-fifth embodiment, and shared portions have therefore been given like reference numerals, a description thereof having been omitted unless there is a particular need. Further, although a depiction in  FIG. 81  has been omitted, the internal configuration of the 3D television  2301  is the same as is illustrated in  FIG. 38 . 
     The fifty-third embodiment of  FIG. 81 , similarly with respect to the twenty-fifth embodiment of  FIG. 38 , uses the piezoelectric bimorph element  2525  having a similar structure to that of the forty-sixth embodiment of  FIG. 69 , as the right-ear cartilage-conduction vibration unit  2324  and the left-ear cartilage-conduction vibration unit  2326 . In other words, the right-ear cartilage-conduction vibration unit  2324  and the left-ear cartilage-conduction vibration unit  2326  exhibit a frequency characteristic for the generation of direct air conduction that trends inversely with regard to the frequency characteristic in cartilage conduction, the generation of air conduction at frequencies below substantially approximately 1 kHz being correspondingly less than at frequencies above the boundary. Specifically, the right-ear cartilage-conduction vibration unit  2324  and the left-ear cartilage-conduction vibration unit  2326  employed in the fifty-third embodiment of  FIG. 81  have a difference of 5 dB or greater between the mean air conduction output from 500 Hz to 1 kHz and the mean air conduction output from 1 kHz to 2.5 kHz, compared to an average, typical speaker designed in consideration of air conduction, and exhibit a frequency characteristic that would be undesirable for a typical speaker. 
     A point of difference in the fifty-third embodiment of  FIG. 81  from the twenty-fifth embodiment of  FIG. 38  lies in that the driving of the above-described right-ear cartilage-conduction vibration unit  2324  and left-ear cartilage-conduction vibration unit  2326  is performed via a frequency characteristic correction unit  4936 . The frequency characteristic correction unit  4936  is provided with a cartilage conduction equalizer  4938  for correcting the frequency characteristic of the sound pressure serving as air conduction sound in the external auditory meatus so as to approach flatness, in consideration of the frequency characteristic specific to cartilage conduction. The cartilage conduction equalizer  4938  fundamentally corrects the frequency characteristic of the drive signals to the right-ear cartilage-conduction vibration unit  2324  and to the left-ear cartilage-conduction vibration unit  2326  equally, but it is also possible to utilize separately corrections for the variations between the right-ear cartilage-conduction vibration unit  2324  and the left-ear cartilage-conduction vibration unit  2326 . The frequency characteristic correction unit  4936  is further provided with a cartilage conduction low-pass filter  4940  for trimming higher frequencies (e.g., trimming 10 kHz and higher). The cartilage conduction low-pass filter  4940  is intended to prevent the unpleasant outward divergence of air conduction, because the right-ear cartilage-conduction vibration unit  2324  and the left-ear cartilage-conduction vibration unit  2326  in the fifty-third embodiment are shaped such that the ear is not covered. The characteristics of the low-pass filter have been determined in consideration that the frequency region advantageous for cartilage conduction (for example, 10 kHz and lower) not be trimmed. In terms of acoustics, it is disadvantageous for an audio device to trim out the audible range (for example, 10 kHz to 20 kHz) and the frequency band thereabove, and the configuration is therefore such that the functions of the cartilage conduction low-pass filter  4940  can be turned off manually in an environment where consideration need not be given to the unpleasant outward divergence of air conduction. 
     Fifty-Fourth Embodiment 
       FIG. 82  is a block diagram of a fifty-fourth embodiment according to an aspect of the present invention. The fifty-fourth embodiment, similarly with respect to the fourth embodiment of  FIG. 8 , is configured as a mobile telephone  5001 . The fifty-fourth embodiment has much in common with the fourth embodiment, and shared portions have therefore been given like reference numerals, a description thereof having been omitted unless there is a need. The fifty-fourth embodiment of  FIG. 82 , similarly with respect to the fifty-third embodiment of  FIG. 81 , uses the piezoelectric bimorph element  2525  having a similar structure to that of the forty-sixth embodiment of  FIG. 69 , serving as the vibration source of the cartilage conduction vibration unit  228 . In other words, the vibration source of the cartilage conduction vibration unit  228  exhibits a frequency characteristic for the generation of direct air conduction that trends inversely with regard to the frequency characteristic in cartilage conduction, the generation of air conduction at frequencies below substantially approximately 1 kHz being correspondingly less than at frequencies above the boundary. Specifically, as with the fifty-second embodiment, the piezoelectric bimorph element employed in the fifty-fourth embodiment of  FIG. 82  has a difference of 5 dB or greater between the mean air conduction output from 500 Hz to 1 kHz and the mean air conduction output from 1 kHz to 2.5 kHz, compared to an average, typical speaker designed with the expectation of air conduction, and exhibits a frequency characteristic that would be undesirable for a typical speaker. 
     A point of difference in the fifty-fourth embodiment of  FIG. 82  from the fourth embodiment of  FIG. 8  lies in the manner in which the above-described piezoelectric bimorph element of the vibration source of the cartilage conduction vibration unit  228  is driven, being performed via a cartilage conduction low-pass filter  5040  for trimming higher frequencies (e.g., trimming 2.5 kHz and higher) and via a cartilage conduction equalizer  5038 . The cartilage conduction equalizer  5038 , similarly with respect to the fifty-third embodiment, corrects the frequency characteristic of the sound pressure serving as air conduction sound in the external auditory meatus so as to approach flatness, in consideration of the frequency characteristic specific to cartilage conduction. An audio signal passed via the cartilage conduction equalizer  5038  will have undergone a frequency characteristic correction in consideration of the frequency characteristic specific to cartilage conduction, and therefore has a different frequency characteristic from an audio signal to the speaker  51  for a videoconferencing function, in which the generation of direct air conduction is presumed. 
     The cartilage conduction equalizer  5038  of the fifty-fourth embodiment, upon detection by the pressure sensor  242  of the state where the ear hole is blocked and the earplug bone conduction effect occurs, automatically switches the frequency characteristic to be corrected from the frequency characteristic used in the normal state of contact to the frequency characteristic used in the state where the earplug bone conduction effect is generated. The difference in correction for the frequency correction to which a switch is thereupon made corresponds to, for example, the difference between the single-dotted line (normal contact  250   g ) and double-dotted line (external auditory meatus occlusion  500   g ) in  FIG. 79 . Specifically, the frequency characteristic is corrected so as to prevent an over-emphasis of the lower sound region when the earplug bone conduction effect occurs and so as to compensate for the loss of unoccluded ear gain due to the occlusion of the external auditory meatus, thus attenuating the change in acoustics between the presence and absence of the earplug bone conduction effect. 
     The cartilage conduction low-pass filter  5040  in the fifty-fourth embodiment has the objectives of preventing sound in the band that can be heard by ear from leaking out and of protecting privacy, and is particularly useful at times of silence. The characteristics of the cartilage conduction low-pass filter  5040  have been determined in consideration that the frequency band at which contact with the ear cartilage has a pronounced effect in increasing sound pressure (for example, 2.5 kHz and lower) not be trimmed. The audio of the mobile telephone, from the start, is trimmed at 3 kHz or higher, but the band from a few hundred Hz to about 2.5 kHz, where the effect of cartilage conduction in increasing sound pressure is high even without unoccluded ear gain, is actively used; frequencies at 2.5 kHz and higher, other than the band at which the effect specific to cartilage conduction emerges, are trimmed, whereby the aforementioned privacy protection can reasonably be fulfilled. As noted above, the effects of the cartilage conduction low-pass filter  5040  are particularly important at times of silence, and therefore, in a preferred configuration, can be turned on and off manually, or can be automatically turned on only in times of silence by the environment-noise microphone  4638  provided in the fiftieth embodiment of  FIG. 75  or a similar element. In the configuration in which the cartilage conduction low-pass filter  5040  can be turned on and off manually, there is the expectation that noise is louder when the cartilage conduction equalizer  5038  uses the frequency characteristic of the state where the earplug bond conduction effect occurs; therefore, the cartilage conduction low-pass filter  5040  is configured so as to be forcibly turned off when turned on manually. 
     The implementation of the features of the present invention illustrated by the embodiments above is not to be limited to the respective embodiments above. For example, the fifty-third embodiment and fifty-fourth embodiment above combine the cartilage conduction vibration source and cartilage conduction equalizer for imparting the generation of air conduction sound having a frequency characteristic that differs from the normal frequency characteristic for generating air conduction in that the final frequency characteristic of air conduction sound having passed through cartilage conduction approaches flatness; however, it is also possible to omit either one thereof. For example, the cartilage conduction equalizer can be omitted when the cartilage conduction vibration source used is well suited for the frequency characteristic of cartilage conduction. Conversely, another possible configuration is one where the cartilage conduction vibration source employed has a frequency characteristic for imparting the generation of air conduction sound according to a normal air conduction speaker, and the function adapted to bring the final frequency characteristic of air conduction having passed through cartilage conduction closer to flatness is concentrated in the cartilage conduction equalizer. 
     Fifty-Fifth Embodiment 
       FIG. 83  is a perspective view and a cross-sectional view relating to a fifty-fifth embodiment according to an aspect of the present invention, which is configured as a mobile telephone  5101 . The fifty-fifth embodiment is consistent with the forty-sixth embodiment illustrated in  FIG. 69 , except for the holding structure of the cartilage conduction vibration source  2525 , which is constituted of a piezoelectric bimorph element, and except for the addition of a T-coil (described later), and therefore shared portions have been assigned like reference numerals and a description thereof has been omitted unless there is a need. 
     First, the holding structure for the cartilage conduction vibration source  2525  in the fifty-fifth embodiment shall now be described. As is clear from the perspective view in  FIG. 83A , the left and right corner parts of the mobile telephone  5101  are provided with cartilage conduction units  5124  and  5126  composed of a hard material. Examples of suitable materials for the cartilage conduction units  5124  and  5126  include an ABS resin, fiber-reinforced plastic, or high-toughness fine ceramic. Elastic bodies  5165   b  and  5165   a  made of a vinyl-based, urethane-based, or other type of material are interposed between the cartilage conduction units  5124  and  5126  and the chassis of the mobile telephone  5101 , and function as a vibration isolation material and as a cushioning material. 
     As is also clear from  FIGS. 83B and 83C , the cartilage conduction units  5124  and  5126  are structured to hold the piezoelectric bimorph element  2525  at the inside thereof. The piezoelectric bimorph element  2525  is also structured to be held at the chassis of the mobile telephone  5101 , without making direct contact, by the interposed elastic bodies  5165   b  and  5165   a . The vibration energy of the piezoelectric bimorph element  2525  is thereby concentrated on the cartilage conduction units  5124  and  5126 , and also thereby prevented from being dispersed to the chassis of the mobile telephone  5101 . 
     Further, as illustrated in  FIG. 83A  by the short-dashed line, a T-coil  5121  is arranged inside the center of the upper part of the mobile telephone  5101  in the fifty-fifth embodiment. The T-coil  5121  is intended to transmit audio information by electromagnetic induction to a hearing aid provided with a corresponding T-coil. A description of the relationship between the manner in which the T-coil transmits audio information and the manner in which cartilage conduction transmits audio information will be provided later. 
       FIG. 84  is a block diagram of the fifty-fifth embodiment of  FIG. 83 , in which like portions have been assigned like reference numerals to those in  FIG. 83  and a description thereof has been omitted. The configuration of the block diagram of  FIG. 84  has much in common with the block diagram of the fifty-fourth embodiment in  FIG. 82 . Since these elements can be referenced, shared parts of the configuration have been given like reference numerals and a description thereof has been omitted. 
     The fifty-fifth embodiment includes the T-coil  5121 , as has already been described, and in a case where the user of the mobile telephone  5101  is wearing a hearing aid provided with a T-coil, audio information can be transmitted to the hearing aid by electromagnetic induction through the T-coil  5121 . The T-coil function of the hearing aid provided with a T-coil can be turned on and off, the configuration being such that a selection can be made to turn the microphone of the hearing aid on or off in a case where the T-coil has been turned on. Correspondingly, a switch  5121   a  of the mobile telephone  5101  of the fifty-fifth embodiment can be turned on or off in response to an operation of the operation unit  9  and a selection can be made as to whether or not to cause the T-coil  5121  to function. In a case where a selection is made to turn the T-coil  5121  on, there is provided a switch  5121   b  for forcibly turning off, in conjunction therewith, the cartilage conduction vibration unit  228 , which includes the piezoelectric bimorph element  2525 . 
     As has already been described, in the state where the ear is plugged as well, cartilage conduction generates air conduction sound within the external auditory meatus along with the earplug bone conduction effect. As a result, in a case where the entrance to the external auditory meatus is blocked by the hearing aid, sound can still be heard without the T-coil  5121  being turned on, due to cartilage conduction, the vibration source of which is the piezoelectric bimorph element  2525 . The cartilage conduction occurs fundamentally due to the cartilage conduction unit  5124  or  5126  being brought into contact with the ear cartilage, but bringing the cartilage conduction unit  5124  or  5126  into contact with the hearing aid also makes cartilage conduction possible due to the generation of air conduction sound inside the external auditory meatus due to the vibration thereof being conducted to the ear cartilage around the hearing aid. Also, depending on the manner in which the cartilage conduction unit  5124  or  5126  is held thereagainst, contact can be made with both the ear cartilage and the hearing aid, air conduction sound being generated inside the external auditory meatus in such a state of concurrence. Thus, the mobile telephone  5101  of the present invention can be utilized by the user of the hearing aid even in the state where the T-coil  5121  has been turned off. 
     The switch  5121   b  is intended to prevent the simultaneous occurrence of the above-described cartilage conduction when the switch  5121   a  has been turned on to cause the T-coil  5121  to function, and the occurrence of any awkwardness compared to sound normally listened to with the T-coil, and is also intended to prevent the unnecessary consumption of power due to cartilage conduction during the operation of the T-coil  5121 . To prevent accidental confusion where cartilage conduction is turned off when the T-coil  5121  is turned on by a mistaken operation, the configuration is such that typically a menu to turn the T-coil  5121  on will not appear in the operation menu of the operation unit  9  displayed on the large-screen display unit  205 ; in a preferred configuration, the T-coil  5121  will not turn on unless a predetermined procedure is followed to intentionally operate the operation unit  9 . 
       FIG. 85  is a side view for describing the manner in which the vibration energy is distributed in the mobile telephone  5101  in the fifty-fifth embodiment described above, and has much in common with  FIG. 2 ; shared portions have therefore been given like reference numerals and a description thereof has been omitted. As illustrated in  FIG. 83 , the cartilage conduction units  5124  and  5126 , which directly hold the piezoelectric bimorph element  2525 , are held at the chassis of the mobile telephone  5101  by the interposed elastic bodies  5165   b  and  5165   a . The vibration of the piezoelectric bimorph element  2525  is thereby effectively conducted to the ear cartilage from the cartilage conduction units  5124  and  5126 , and moreover the vibration is less prone to be conveyed to the chassis of the mobile telephone  5101 , because the piezoelectric bimorph element  2525  is not in direct contact therewith. In other words, the structure is such that the vibration energy of the piezoelectric bimorph element  2525  is concentrated on the cartilage conduction units  5124  and  5126 , and is not dispersed to the chassis of the mobile telephone  5101 . 
     A specific description by way of  FIG. 85  shall now be provided. Because the vibration energy is concentrated on the cartilage conduction units  5124  and  5126 , the amplitude and acceleration of vibration are greatest at positions ( 1 ) and ( 2 ) on the surface of the chassis of the mobile telephone  5101  (see the encircled numbers  1 ,  2  in  FIG. 85 ), and a position ( 3 ) between the cartilage conduction units  5124  and  5126  on the chassis of the mobile telephone  5101  (see the encircled number  3  in  FIG. 85 ) has somewhat less amplitude and acceleration of vibration. Also, a position ( 4 ) and a position ( 5 ) (see the encircled numbers  4 ,  5  in  FIG. 85 ) are separated from the positions ( 1 ) and ( 2 ) in that order, and have correspondingly decreasing amplitude and acceleration of vibration on the surface of the chassis of the mobile telephone  5101 . For example, the amplitude and acceleration of vibration on the surface of the chassis of the mobile telephone  5101  at the position ( 5 ), which is separated from each of the positions ( 1 ) and ( 2 ) by 5 cm or more, become ¼ or less (25% or less) of the amplitude and acceleration of vibration on the surface at the cartilage conduction units  5124  and  5126 .  FIG. 85A  illustrates the state where the mobile telephone  5101  in which vibration is thus distributed is held up to the right ear  28  and suitable cartilage conduction is obtained, and  FIG. 85B  illustrates the state where the mobile telephone  5101  is held up to the left ear  30  and similarly suitable cartilage conduction is obtained. 
     The feature by which the vibration energy for the cartilage conduction described above is concentrated at the parts of expected contact with the ear cartilage at the entrance part of the external auditory meatus is not limited to the fifty-fifth embodiment illustrated in  FIGS. 83 to 85 , and also appears in several other embodiments that have already been described. For example, the first to third, eleventh to fourteenth, twenty-ninth to thirty-third, thirty-fifth, thirty-sixth, forty-second to forty-fourth, forty-sixth to fiftieth, fifty-second, and fifty-fifth embodiments are examples where the vibration acceleration or amplitude of vibration at the parts of expected contact is greater than the vibration acceleration or amplitude of vibration at portions separated from the parts of expected contact, this effect being particularly pronounced in configurations as in the twenty-ninth, thirtieth to thirty-third, forty-second to forty-third, forty-sixth to fiftieth, fifty-second, and fifty-fifth embodiments, as will be described later. For reasons that will be described later, the vibration acceleration or amplitude of vibration decreases monotonically, relative to the parts of expected contact, as the distance from the parts of expected contact increases. 
     The parts of expected contact, at which the vibration energy for cartilage conduction is concentrated in the present invention, do not protrude from the chassis, and are not shaped so as to hinder the use of the mobile telephone. Further, the parts of expected contact are found at positions removed from both the central up-down axis and central left-right axis of the chassis, and are suitably disposed in contact with the ear cartilage at the entrance part of the external auditory meatus. Specifically, the parts of expected contact are found at corner parts or an upper side part or side surface part in the vicinity of the corner parts of the mobile telephone. In other words, the arrangement configuration described above obtains a suitable configuration by which the surface of the outer wall is brought into contact with at least a part of the ear cartilage around the entrance part of the external auditory meatus without making contact with the auricular helix. 
     As described above, in the present invention, the vibration energy can be concentrated at the parts of expected contact with the ear cartilage at the entrance part of the external auditory meatus not only in the fifty-fifth embodiment of  FIGS. 83 to 85  but also in other embodiments. To classify this feature, firstly, the twenty-ninth embodiment, the thirtieth embodiment, the second modification example of the thirty-first embodiment, the thirty-second embodiment, the thirty-third embodiment, and the fifty-fifth embodiment are first examples where elastic bodies create an isolation between the parts of expected contact and the chassis of the mobile telephone, whereby the feature is realized. The twenty-ninth embodiment, the thirtieth embodiment, the thirty-second embodiment, and the thirty-third embodiment are second examples where the primary vibration direction of the piezoelectric bimorph element is avoided and the same is supported on the chassis of the mobile telephone, whereby the vibration energy is concentrated at the parts of expected contact. The thirtieth embodiment, the thirty-first embodiment, and the forty-seventh embodiment are third examples where there is a reduced surface area of contact between the parts of expected contact and the chassis of the mobile telephone supporting the same, whereby the vibration energy is concentrated at the parts of expected contact. The forty-second to forty-fourth embodiment, the forty-sixth embodiment and the modification example thereof, the forty-eighth to fiftieth embodiments, the fifty-second embodiment, and the fifty-fifth embodiment are fourth examples where the holding position of the vibrator is limited to the vicinity of the parts of contact, whereby the vibration energy is concentrated at the parts of expected contact. The forty-sixth embodiment and the modification example thereof, the forty-eighth to fiftieth embodiments, the fifty-second embodiment, and the fifty-fifth embodiment are fifth examples where the parts of expected contact have a different material from that of the chassis of the mobile telephone, whereby the vibration energy is concentrated at the parts of expected contact. However, as is clear from the fact that some embodiments are duplicated in the classifications described above, the features classified as above can in practice be employed in a plurality of combinations. 
     The various features of the present invention described above are not limited to the embodiments described above. For example, as a modification example of the fifty-fifth embodiment, another possible configuration is one where a hole having a greater cross-sectional area than that of the piezoelectric bimorph element  2525  is opened at each of the elastic bodies  5165   b  and  5165   a , the cross-section of which is illustrated by  FIG. 83B , the piezoelectric bimorph element  2525  being held through the holes by the cartilage conduction units  5124  and  5126 . Such a case is structured such that the piezoelectric bimorph element  2525  does not make direct contact with the elastic bodies  5165   b  and  5165   a , and it becomes possible to prevent the vibration energy of the piezoelectric bimorph element  2525  from being dispersed to the chassis of the mobile telephone  5101  via the elastic bodies  5165   b  and  5165   a.    
     The fifty-fifth embodiment described above, similarly with respect to the forty-sixth embodiment illustrated in  FIG. 69 , is structured such that the vibration of both ends of a single piezoelectric bimorph element  2525  is conducted to the left and right cartilage conduction units  5124  and  5126 ; however, the implementation of a feature such as that of the fifty-fifth embodiment is not to be limited thereto. For example, the holding structure of the fifty-fifth embodiment of  FIG. 83  may be applied to the structure in which one side of the piezoelectric bimorph element  2525  is supported by the cantilever structure, as in the forty-second embodiment of  FIG. 65 . Furthermore, in a configuration as in the fifty-second embodiment of  FIG. 77 , where the right ear piezoelectric bimorph element  2525   b  and the left ear piezoelectric bimorph element  2525   a  are employed, the holding structure of the fifty-fifth embodiment of  FIG. 83  may be applied to the manner in which the same are each supported by the cantilever structure. 
     As has already been described, the ability to independently control the right ear and left-ear cartilage-conduction vibration unit s, as in the first to third embodiments in FIGS.  1  to  7  and the fifty-second embodiment in  FIG. 77 , makes it possible to stop the vibration of the vibration unit, which is not brought into contact with the ear cartilage. In such a case, in the distribution of vibration energy in the case where the vibration of the cartilage conduction unit  5126  is stopped in  FIG. 85A  illustrating the state where the cartilage conduction unit  5124  is held against the right ear  28 , the amplitude and acceleration of vibration are greatest at the position ( 1 ); the amplitude and acceleration of vibration subsequently decrease at the position ( 3 ), the position ( 2 ), the position ( 4 ), and the position ( 5 ), in this order. By contrast, in the distribution of vibration energy in the case where the vibration of the cartilage conduction unit  5124  is stopped in  FIG. 85B  illustrating the state where the cartilage conduction unit  5126  is held against the left ear  30 , the amplitude and acceleration of vibration are greatest at the position ( 2 ); the amplitude and acceleration of vibration subsequently decrease at the position ( 3 ), the position ( 1 ), the position ( 4 ), and the position ( 5 ), in this order. 
     Fifty-Sixth Embodiment 
       FIG. 86  is a perspective view and a cross-sectional view relating to a fifty-sixth embodiment according to an aspect of the present invention, which is configured as a mobile telephone  5201 . The fifty-sixth embodiment is consistent with the fifty-fifth embodiment illustrated in  FIG. 83 , except for the holding direction of the cartilage conduction vibration source  2525  constituted of the piezoelectric bimorph element; shared portions have been given like reference numerals, and a description thereof has been omitted unless there is a need. 
     In the fifty-fifth embodiment of  FIG. 83 , the metal sheet  2597  of the cartilage conduction vibration source  2525  is arranged so as to be parallel to the front surface of the mobile telephone  5101 , and the primary vibration direction is oriented orthogonal to the GUI display unit  3405 . By contrast, in the fifty-sixth embodiment of  FIG. 86 , a metal sheet  2599  of a cartilage conduction vibration unit  5225  is arranged so as to be perpendicular to the front surface of the mobile telephone  5201 , as a result of which the primary vibration direction of the cartilage conduction vibration unit  5225  becomes parallel to the GUI display unit  3405 , similarly with respect to the first modification example of the forty-second embodiment illustrated in  FIG. 65C . The configuration of the fifty-sixth embodiment is suitable for usage where, the front surface side of a corner part (the cartilage conduction unit  5124  or  5126 ) of the mobile telephone  5201  being held against the ear cartilage identically with respect to the case illustrated in  FIG. 85 , the top surface side of the corner part is held against the ear cartilage in such a form as to lightly push upward, similarly with respect to the first modification example of the forty-second embodiment. Because the vibration is concentrated on the cartilage conduction unit  5124  or  5126 , sufficient cartilage conduction can be obtained merely by bringing only the front surface side of a corner part (the cartilage conduction unit  5124  or  5126 ) up against the ear cartilage. 
     In the fifty-sixth embodiment of  FIG. 86 , because the primary vibration direction of the cartilage conduction vibration unit  5225  is parallel to the front surface of the mobile telephone  5201  (which includes the GUI display unit  3405 ), there is a smaller vibration component transmitted to the front surface and rear surface, which account for a large surface area of the outer surfaces of the mobile telephone  5201 . As a result, there can be a further reduction in sound leakage due to air conduction sound generated at such portions of the large surface area. 
     The cartilage conduction vibration unit  5225  oriented in the manner described above as in the fifty-sixth embodiment of  FIG. 86  is not limited to the fifty-sixth embodiment, but rather can also be employed in the forty-sixth embodiment of  FIG. 69 , the forty-sixth embodiment of  FIG. 71 , the forty-ninth embodiment of  FIG. 74 , and other embodiments. 
     Fifty-Seventh Embodiment 
       FIG. 87  is a block diagram relating to a fifty-seventh embodiment according to an aspect of the present invention, which is configured as a mobile telephone  5301 . A piezoelectric bimorph element  5325  constituting the cartilage conduction vibration unit in the fifty-seventh embodiment has a drive circuit configured as a power management circuit for supplying, together with a single-chip integrated power management IC  5303 , power to each of the parts of the mobile telephone  5301 . 
     The integrated power management IC  5303  has a power management unit  5353  and supplies different, respectively predetermined power voltages to an RF circuit unit  5322  connected to an analog baseband unit  5313  and an antenna  5345  and coupled to a digital baseband unit  5312 , and to other elements constituting the telephone communication unit, on the basis of the power supply from a battery  5348 . The power management unit  5353  further supplies different, respectively predetermined power voltages to: an application processor  5339  corresponding to the controller  39  or the like illustrated in other embodiments, a camera unit  5317  (depicted as a consolidation of the backside main camera and videoconferencing function in-camera illustrated in other embodiments), a liquid crystal display device  5343  and touch panel  5368  in a display unit  5305 , and other elements. The application processor  5339 , which is linked with a memory  5337  (depicted as a consolidation of a program holding function and a data writing and holding function), controls the entirety of the mobile telephone  5301  and is capable transferring signals with external apparatuses via a memory card  5319  (depicted as a consolidation of a slot and a card) and a USB™ connection terminal  5320 . 
     The power management unit  5353  also supplies different, respectively predetermined power voltages to a controller  5321 , an analog front-end unit  5336 , an amplifier  5341  for a videoconferencing function speaker  5351 , a cartilage conduction acoustic signal processing unit  5338 , a charge pump circuit  5354 , and other elements within the integrated power management IC  5303 . The charge pump circuit  5354  is intended to boost the voltage for the piezoelectric bimorph element  5325 , which requires high voltage. 
     The analog front-end unit  5336  receives an analog audio signal from the application processor  5339 , which is outside the integrated power management IC  5303  and supplies the same to the videoconferencing function speaker  5351  via the amplifier  5341 , also supplying the analog audio signal to an earphone jack  5314  and the cartilage conduction acoustic signal processing unit  5338 . The analog front-end unit  5336  also transmits an analog audio signal picked up from the user by the microphone  5323  to the outside application processor  5339 . 
     The charge pump circuit  5354  operates to boost voltage in cooperation with an exterior attached condenser  5355 , which is connected via exterior attached terminals  5355   a  and  5355   b , and supplies to the amplifier  5340  the voltage needed to drive the piezoelectric bimorph element  5325 . The audio signal from the analog front-end unit  5336  thereby drives the piezoelectric bimorph element  5325  via the cartilage conduction acoustic signal processing unit  5338  and the amplifier  5340 . Examples corresponding to the functions of the cartilage conduction acoustic signal processing unit  5338  include the acoustics adjustment unit  238  and waveform inverter  240  illustrated in the fourth embodiment of  FIG. 8 , the cartilage conduction low-pass filter  5040  and cartilage conduction equalizer  5038  illustrated in the fifty-fourth embodiment of  FIG. 82 , but there is no limitation thereto. 
     The controller  5321  transfers digital control signals with the application processor  5339 , which is outside the integrated power management IC  5303 , and controls the power management unit  5353 . The controller  5321  controls the analog front-end unit  5336  on the basis of a command from the application processor  5339 , and performs such operations as switching between sending the analog audio signal received from the application processor  5339  to the amplifier  5341  or sending the same to the cartilage conduction acoustic signal processing unit  5338 , in order to drive the videoconferencing function speaker  5351 . The analog front-end unit  5336  also performs such processing as preventing the “popping sound” that accompanies the switching from being outputted to the earphone jack  5314  and other elements. 
     The controller  5321  also transfers digital control signals with the application processor  5339 , which is outside the integrated power management IC  5303 , and controls the cartilage conduction acoustic signal processing unit in a manner relating to the acoustics adjustment, waveform inversion, the cartilage conduction low-pass filter, and the cartilage conduction equalizer, among others as exemplified above. 
     Because the fifty-seventh embodiment of  FIG. 87 , as described above, has the drive circuit of the cartilage conduction vibration unit configured as a single-chip integrated IC together with a power management circuit, the cartilage conduction vibration unit can be driven directly, and power voltage can be supplied to the cartilage conduction vibration unit integratedly with the supply of power voltage to the various constituent elements inside the mobile telephone, it being possible to also integrate the control thereof. Also, having the cartilage conduction acoustic signal processing unit for the cartilage conduction vibration unit configured as a single-chip integrated IC together with a power management part further allows for the control of the audio signals of the piezoelectric bimorph element to be integrated. In a case where the piezoelectric bimorph element is employed as the cartilage conduction vibration unit, although high voltage is needed to drive the same, having the drive circuit of the cartilage conduction vibration unit configured as a single-chip integrated IC together with a power management unit, as in the fifty-seventh embodiment of  FIG. 87 , makes it possible to drive the piezoelectric bimorph element without the need to add a separate chip for a boosted-voltage circuit. Having the cartilage conduction acoustic signal processing unit dedicated to driving the cartilage conduction vibration unit configured as a single-chip integrated IC together with a power management part further allows for the control of the audio signals of the piezoelectric bimorph element to be integrated. It is accordingly possible to endow the mobile telephone with a suitable cartilage conduction function merely by inputting an ordinary audio signal to the integrated IC and connecting the cartilage conduction vibration unit to the integrated IC. 
     Further, having the analog-front end unit configured as a single-chip integrated IC together with the power management unit allows for the output of audio signals to be collectively switched and adjusted. Specifically, the transfer of digital control signals between the integrated IC and the application processor, relating to the functions of the overall mobile telephone inclusive of the functions of the cartilage conduction vibration unit, can be integrated with the transfer of analog audio signals between the integrated IC and the application processor. 
     The circuit configuration in which the drive circuit of the cartilage conduction vibration unit is configured as the power management unit and the single-chip integrated IC, as in the fifty-seventh embodiment of  FIG. 87 , can also be applied to the various other embodiments that have already been described. 
     Fifty-Eighth Embodiment 
       FIG. 88  is a perspective view and a cross-sectional view relating to a fifty-eighth embodiment according to an aspect of the present invention, which is configured as a mobile telephone  5401 . The fifty-eighth embodiment is consistent with the fifty-fifth embodiment illustrated in  FIG. 83 , except for a configuration intended as a countermeasure against sound leakage due to air conduction sound (described later), and therefore shared portions have been given like reference numerals and a description thereof has been omitted unless there is a need. 
     In the fifty-eighth embodiment of  FIG. 88 , similarly with respect to the fifty-fifth embodiment illustrated in  FIG. 83 , there is slight vibration conducted to the chassis of the mobile telephone  5401  via the elastic bodies  5165   b  and  5165   a  from the cartilage conduction units  5124  and  5126  composed of a hard material, which hold the cartilage conduction vibration source  2525 . The front surface and rear surface of the mobile telephone  5401 , which account for a large surface area of the outer surfaces thereof, are thereby made to vibrate, and slight sound leakage due to air conduction sound is generated. In the fifty-eighth embodiment of  FIG. 88 , the outer surface of the chassis of the mobile telephone  5401 , except for the portions of the GUI display unit  3405  and the microphone  23 , is covered by an elastic body  5463 , as a countermeasure against such sound leakage. Herein, the elastic body  5463  is bonded so as to be integrated with the chassis of the mobile telephone  5401 . The portion of the GUI display unit  3405  then becomes an opening part so as not to hinder GUI operation. The portion of the microphone  23  is configured as the microphone cover unit  467  having a sponge-like or similar structure that will not hinder the air conduction of audio, similarly with respect to the fifth embodiment of  FIG. 11   
     The elastic body  5463  for covering the outer surface of the chassis of the mobile telephone  5401  is preferably made of the same vinyl-based, urethane-based, or other type of vibration insulation material and cushioning material as the elastic bodies  5165   b  and  5165   a , or such a material similar thereto. The cartilage conduction units  5124  and  5126  composed of a hard material, which hold the cartilage conduction vibration source  2525 , are, in the fifty-eighth embodiment of  FIG. 88 , thereby in contact with the chassis of the mobile telephone  5401  through being included via the elastic bodies  5165   b ,  5165   a  and the elastic body  5463 . The cartilage conduction vibration source  2525  accordingly does not make direct contact with the chassis of the mobile telephone  5401 . 
     Also, because the elastic body  5463  is not an insertable/releasable cover as in the fifth embodiment of  FIG. 11 , but is bonded so as to be integrated with a large portion of the surface area of the surface of the chassis of the mobile telephone  5401 , the vibration of the large portion of the surface area of the surface of the chassis of the mobile telephone  5401  is suppressed by the weight and elasticity thereof in both the interior and exterior directions over the amplitude of vibration, and vibration energy is also absorbed. The surface of the mobile telephone  5401 , which is contact with the air, is also given elasticity. The air conduction sound generated from the surface of the chassis of the mobile telephone  5401 , caused by the vibration of the cartilage conduction vibration source  2525  across the chassis of the mobile telephone  5401 , is thereby attenuated. On the other hand, because the elastic body  5463  has an acoustic impedance approximating that of the ear cartilage, there is favorable cartilage conduction to the ear cartilage from the cartilage conduction units  5124  and  5126 . The manner in which the elastic body  5463  covers the surface of the chassis of the mobile telephone  5401  also functions as a protection for when the mobile telephone  5401  collides with an external unit. 
     Fifty-Ninth Embodiment 
       FIG. 89  is a perspective view and a cross-sectional view relating to a fifty-ninth embodiment according to an aspect of the present invention, which is configured as a mobile telephone  5501 . The fifty-ninth embodiment is consistent with the forty-second embodiment illustrated in  FIG. 65 , except for a configuration intended as a countermeasure against sound leakage due to air conduction sound, and therefore portions shared by cross-sectional views in  FIGS. 89B and 89C  with the cross-sectional views in  FIGS. 65A and 65B  have been assigned like reference numerals, and a description thereof has been omitted unless there is a need. The perspective view of  FIG. 89A  is consistent with the fifty-eighth embodiment of  FIG. 88A , and therefore shared portions have been assigned like reference numerals and a description thereof has been omitted unless there is a need. 
     In the fifty-ninth embodiment of  FIG. 89 , one end of the piezoelectric bimorph element  2525  is held in a hole in a support structure  3800   a  for holding the cartilage conduction vibration source  2525 , the support structure  3800   a  extending inward from a side surface  3807  and top surface  3807   a  of the mobile telephone  5501 . The vibration of the cartilage conduction vibration source  2525  is therefore conducted to the chassis of the mobile telephone  5501  via the side surface  3807  and top surface  3807   a  of the mobile telephone  5501  from the support structure  3800   a , and the front surface and rear surface of the mobile telephone  5501 , which account for a large surface area of the outer surfaces thereof, are therefore made to vibrate. There is also greater sound leakage due to the air conduction sound generated thereby than there is in the case of the fifty-sixth embodiment of  FIG. 86 . However, in the fifty-ninth embodiment of  FIG. 89 , similarly with respect to the fifty-eighth embodiment of  FIG. 88 , the outer surface of the chassis of the mobile telephone  5501 , except for the portions of the GUI display unit  3405  and the microphone  23 , is covered by an elastic body  5563 , as a countermeasure against such sound leakage. Herein, the elastic body  5563  is bonded so as to be integrated with the chassis of the mobile telephone  5501 . The portion of the GUI display unit  3405  then becomes an opening part so as not to hinder GUI operation. The portion of the microphone  23  is configured as the microphone cover unit  467  having a sponge-like or similar structure that will not hinder the air conduction of audio, similarly with respect to the fifth embodiment of  FIG. 11 . This is a point of similarity with the fifty-eighth embodiment of  FIG. 88 . 
     The elastic body  5563  for covering the outer surface of the chassis of the mobile telephone  5501  is preferably made of a vinyl-based, urethane-based, or other type of vibration insulation material and cushioning material, similarly with respect to the fifty-eighth embodiment of  FIG. 88 . Due to the above configuration, in the fifty-ninth embodiment of  FIG. 89  as well, the vibration of a large portion of the surface area of the surface of the chassis of the mobile telephone  5501  is suppressed by the weight and elasticity of the covering elastic body  5563  in both the interior and exterior directions over the amplitude of vibration, and vibration energy is also absorbed. The surface of the mobile telephone  5501 , which is contact with the air, is also given elasticity. The air conduction sound generated from the surface of the chassis of the mobile telephone  5501 , caused by the vibration of the cartilage conduction vibration source  2525 , is thereby attenuated. On the other hand, because the elastic body  5563  has an acoustic impedance approximating that of the ear cartilage, there is favorable cartilage conduction to the ear cartilage from the upper part corner  3824 , which is a suitable site to be brought up against the tragus or other part of the ear cartilage. A further point of similarity with the fifty-eighth embodiment of  FIG. 88  is that the manner in which the elastic body  5563  covers the surface of the chassis of the mobile telephone  5501  also functions as a protection for when the mobile telephone  5501  collides with an external unit. 
     Sixtieth Embodiment 
       FIG. 90  is a perspective view and a cross-sectional view relating to a sixtieth embodiment according to an aspect of the present invention, which is configured as a mobile telephone  5601 . The sixtieth embodiment is consistent with the forty-sixth embodiment illustrated in  FIG. 69 , except for a configuration intended as a countermeasure against sound leakage due to air conduction sound, and therefore shared portions are given like reference numerals, and a description thereof has been omitted unless there is a need. 
     In the sixtieth embodiment of  FIG. 90 , similarly with respect to the forty-sixth embodiment of  FIG. 69 , elastic body units  5663   a  and  5663   b , serving as protectors, are provided to the two corners of the upper part of the mobile telephone  5601 . The inner sides thereof have a dual purpose as units for holding both ends of the cartilage conduction vibration source  2525 , and the outer sides have a dual purpose as cartilage conduction units for making contact with the ear cartilage. The elastic body units  5663   a  and  5663   b  utilize an elastic material having an acoustic impedance approximating that of ear cartilage (a silicone rubber; a mixture of a silicone rubber and a butadiene rubber; a natural rubber; a structure formed using these varieties of rubber in which air bubbles are sealed; a structure, such as can be seen in transparent packaging sheet materials and the like, in which a layer of groups of air bubbles is sealed separated by a thin film of synthetic resin; or the like). 
     In the sixtieth embodiment of  FIG. 90  as well, a substantial component of the vibration of the elastic body units  5663   a  and  5663   b  for holding the cartilage conduction vibration source  2525  is conducted to the chassis of the mobile telephone  5601 , and the front surface and rear surface of the mobile telephone  5601 , which account for a large surface area of the outer surfaces thereof, are made to vibrate, thus generating air conduction sound. However, in the sixtieth embodiment of  FIG. 90  as well, there extends in a sheet-shaped manner from the elastic body units  5663   a  and  5663   b  an elastic body  5663  composed of the same material, as a countermeasure against sound leakage caused by the aforesaid air conduction sound; the elastic body  5663  covers the outer surfaces of the mobile telephone  5601  except for the portions of the GUI display unit (the same part as a GUI display unit  3405  in  FIGS. 88 and 99 ) and the microphone  23 . In the sixtieth embodiment of  FIG. 90  as well, similarly with respect to the fifty-eighth embodiment of  FIG. 88  and the fifty-ninth embodiment of  FIG. 89 , the elastic body  5663  is bonded so as to be integrated with the chassis of the mobile telephone  5601 . The portion of the GUI display unit  3405  then becomes an opening part so as not to hinder GUI operation. The portion of the microphone  23  is configured as the microphone cover unit  467  having a sponge-like or similar structure that will not hinder the air conduction of audio, similarly with respect to the fifth embodiment of  FIG. 11 . This is a point of similarity with the fifty-eighth embodiment of  FIG. 88  and the fifty-ninth embodiment of  FIG. 89 . 
     Due to the above configuration, in the sixtieth embodiment of  FIG. 90  as well, the vibration of a large portion of the surface area of the surface of the chassis of the mobile telephone  5601  is suppressed by the weight and elasticity of the covering elastic body  5663  in both the interior and exterior directions over the amplitude of vibration, and vibration energy is also absorbed. The surface of the mobile telephone  5601 , which is in contact with the air, is also given elasticity. The air conduction sound generated from the surface of the chassis of the mobile telephone  5601 , caused by the vibration of the cartilage conduction vibration source  2525 , is thereby attenuated. The manner in which the elastic body  5663  covers the surface of the chassis of the mobile telephone  5601  also functions as a protection for those portions other than the elastic body units  5663   a  and  5663   b.    
     Sixty-First Embodiment 
       FIG. 91  is a perspective view and a cross-sectional view relating to a sixty-first embodiment according to an aspect of the present invention, which is configured as a mobile telephone  5701 . The sixty-first embodiment is consistent with the fifty-fifth embodiment illustrated in  FIG. 83 , except for a configuration intended as a countermeasure against sound leakage due to air conduction sound, and therefore shared portions are given like reference numerals, and a description thereof has been omitted unless there is a need. 
     In the sixty-first embodiment of  FIG. 91 , similarly with respect to the fifty-fifth embodiment illustrated in  FIG. 83 , both ends of the cartilage conduction vibration source  2525  are held by the cartilage conduction units  5124  and  5126  composed of a hard material, and are supported by the chassis of the mobile telephone  5701  via the elastic bodies  5165   b  and  5165   a . In such a structure, as has already been described in the fifty-eighth embodiment of  FIG. 88 , there is slight vibration conveyed to the chassis of the mobile telephone  5701 , thus generating sound leakage due to air conduction sound generated from the front surface and rear surface thereof. As a countermeasure to this sound leakage, the sixty-first embodiment of  FIG. 91  has a pressure-fixation structure  5701   h  made of a screwed-in metal sheet or the like for pressing and affixing internal configuration components  5748  of the mobile telephone  5701 , including a battery and the like, to the inner surface of the chassis of the mobile telephone  5701 . The weight of the internal configuration  5748 , including the battery and the like, is thereby integrated with the chassis of the mobile telephone  5701 , and the vibration of a large portion of the surface area of the chassis is thereby suppressed across both the interior and exterior directions in the amplitude thereof, wherefore the generation of air conduction sound is attenuated. 
     In the sixty-first embodiment of  FIG. 91 , there is further a surplus space within the chassis of the mobile telephone  5701 , which is filled in with a sound-absorbent packing material  5701   i  composed of nonwoven cloth or the like. The surplus space within the chassis of the mobile telephone  5701  is thereby finely sub-divided and the air within the chassis is prevented from resonating, thus attenuating the generation of air conduction sound. To facilitate understanding,  FIG. 91C  provides a simplified depiction of the manner in which the internal configuration  5748 , the pressure fixation structure  5701   h , and the sound-absorbent packing material  5701   i  are packed, but the structure therefor is in practice very complex; also, the pressure fixation structure  5701   h  is not limited to pressing and fixing the internal configuration  5748  only to the rear surface side of the mobile telephone  5701 , as is depicted. For the fine sub-division of the surplus space within the chassis of the mobile telephone  5701 , a barrier wall also may be provided to the inner side of the chassis, instead of packing in the sound-absorbing packing material  5701   i.    
     The implementation of the various features of the present invention illustrated by the embodiments above is not to be limited to the respective embodiments above. For example, in  FIGS. 88 to 90  above, on the rear surface and other portions accounting for a large surface area of the outer surfaces of the mobile telephone, the width of the cross-sections of the elastic bodies for covering has been depicted as being approximately equivalent to the width of the cross-section of the chassis. However, as long as the strength of the chassis is maintained, the thickness of the cross-section of the chassis can be reduced as much as possible, and the thickness of the cross-section of the elastic body for covering the same can be increased as much as possible, so that the chassis theoretically comprises the elastic body, and the effect of preventing sound leakage is improved. At such a time, a configuration in which the barrier wall for finely sub-dividing the surplus space is provided to the interior of the chassis is further advantageous in retaining strength, and contributes to rendering the chassis thinner. 
     In the sixtieth embodiment illustrated in  FIG. 90 , the elastic body units  5663   a  and  5663   b  having multiple purposes as protectors, as parts for holding both ends of the cartilage conduction vibration source  2525 , and as cartilage conduction units are contiguous with the elastic body  5663 , being of the same material, but there is no limitation to such a configuration. For example, the elastic body units  5663   a  and  5663   b  may be components that are separated from the elastic body  5663 , or may necessarily not be in contact. The elastic body units  5663   a  and  5663   b  may also be constituted of a different material from that of the elastic body  5663 . 
     Further, for the sake of simplicity, the fifty-eighth to sixtieth embodiments illustrated in  FIGS. 88 to 90  depict configurations in which the vibration of the chassis of the mobile telephone is covered and suppressed by an exterior elastic body, and the sixty-first embodiment of  FIG. 91  depicts a configuration in which the vibration of the chassis of the mobile telephone is suppressed by the pressure fixation of the weight of the internal configuration of the mobile telephone. However, there is no limitation to the case where these elements are employed separately, as in the embodiments, but rather the configuration may be such that the two are used concurrently and the vibration of the interior and exterior of the chassis of the mobile telephone is suppressed therefrom. 
     Sixty-Second Embodiment 
       FIG. 92  is a perspective view and a side view of a sixty-second embodiment according to an aspect of the present invention, configured as a land-line telephone  5800 . As shown in perspective view in  FIG. 92(A) , the land-line telephone  5800  includes a telephone base station  5801  and a cordless handset  5881 . The telephone base station  5801  is furnished with a display unit  5805 , a videoconferencing camera  5817 , a videoconferencing microphone  5823 , a videoconferencing speaker  5851 , and the like. 
       FIG. 92(B)  shows the handset  5881  of the land-line telephone  5800  in a state positioned upright in a charger  5848 . This handset  5881  is identical to the cordless handset  5881  in  FIG. 92(A) , and is therefore illustrated with the same symbol. As shown in  FIG. 92(B) , the cordless handset or the handset  5881  (hereinafter, both shall be denoted as “cordless handset  5881 ”) has a cartilage conduction unit  5824  that defines a gentle convex face; when the cordless handset  5881  is placed against the ear, this cartilage conduction unit  5824  fits naturally into a depression of the ear having the external auditory meatus as the bottom, coming into contact with the ear cartilage over a wide area. The cordless handset (or handset)  5881  also has an outgoing-talk unit  1423  comparable to that shown in the mobile telephone embodiment. 
       FIG. 92(C)  illustrates a side surface of the cordless handset (or handset)  5881 , and shows the cordless handset (or handset)  5881  placed against an ear  30 , at which time the gentle convex face of the cartilage conduction unit  5824  fits into the depression of the ear having the external auditory meatus as its bottom, and comes into contact with the ear cartilage over a wide area. As will be clear from the side view in  FIG. 92(C) , in the sixty-second embodiment, the cartilage conduction unit  5824  has a shape defined by a portion of a spherical face. In an ordinary handset, the ear-contacting part has a concave face for forming a closed space to the front of the ear; however, the handset for cartilage conduction according to the present invention conversely has a convex face, and can be given a natural shape readily fitting into the depression of the ear having the external auditory meatus as its bottom. 
       FIG. 93  is a block diagram of the sixty-second embodiment, in which identical components have been assigned the same reference numerals as in  FIG. 92 . Additionally, as the configuration shown in the block diagram has much in common with the seventeenth embodiment of  FIG. 29 , the same reference numerals as those assigned to these parts have been assigned to corresponding portions. Descriptions of these identical or corresponding portions are omitted, unless there is a particular need. Even for portions not assigned identical numerals, for example, the videoconferencing camera  5817 , the portion corresponds to the videoconferencing inside camera  17  in the mobile telephone  1601  of  FIG. 29 , and the functions thereof are basically identical. Moreover, while the sixty-second embodiment pertains to a land-line telephone and therefore represents a different system from a mobile telephone, the telephone functionality is basically identical, and therefore the illustration of a telephone function unit  5845  in  FIG. 93  is similar. This is true of the power supply unit as well: while the power source differs, the functions are basically identical, and therefore the same reference numeral as in  FIG. 29  is assigned.  FIG. 93  also illustrates charging contacts  1448   a  and  1548   a , for charging the cordless handset (or handset)  5881  while placed in the telephone base station  5801  or the charger  5848 . 
       FIG. 94  shows side cross sectional views of cordless handsets in the sixty-second embodiment of  FIG. 92  and modification examples thereof, showing the relationship of a piezoelectric bimorph element constituting the cartilage conduction vibration source, and the cartilage conduction unit having a convex face.  FIG. 94(A)  shows a side cross sectional view of the cordless handset  5881  of the sixty-second embodiment, in which a vibration conductor  5827  is affixed to the inside of a cartilage conduction unit  5824 , with the center part of a piezoelectric bimorph element  2525   d  being supported by this vibration conductor  5827 . Both ends of the piezoelectric bimorph element  2525   d  can vibrate freely, the counteraction thereof being transmitted to the cartilage conduction unit  5824  via the vibration conductor  5827 . 
       FIG. 94(B)  is a side cross sectional view of a cordless handset  5881   a  in a first modification example of the sixty-second embodiment. Whereas the cartilage conduction unit  5824  in the cordless handset  5881   a  of the sixty-second embodiment was a partial spherical face, the cartilage conduction unit  5824   a  in the first modification example has an acute-angled conical (cone) shape. The configuration whereby the vibration conductor  5827   a  is affixed to the inside of the cartilage conduction unit  5824   a , and supports the center part of a piezoelectric bimorph element  2525   e , is shared with the sixty-second embodiment. 
       FIG. 94(C)  is a side cross sectional view of a cordless handset  5881   b  in a second modification example of the sixty-second embodiment. As in the first modification example, the cartilage conduction unit  5824   b  in the cordless handset  5881   b  of the second modification example has an acute-angled conical (cone) shape. In the second modification example of  FIG. 94(C) , a vibration conductor  5827   b  is affixed to the inside of the cartilage conduction unit  5824   b , and supports one end of a piezoelectric bimorph element  2525   f . The other end of the piezoelectric bimorph element  2525   f  can vibrate freely, the counteraction thereof being transmitted to the cartilage conduction unit  5824   b  via the vibration conductor  5827   b.    
       FIG. 94(D)  is a side cross sectional view of a cordless handset  5881   c  in a third modification example of the sixty-second embodiment. As in the first modification example and the second modification example, the cartilage conduction unit  5824   c  in the cordless handset  5881   c  of the third modification example has an acute-angled conical (cone) shape. In the third modification example of  FIG. 94(D) , a low-end piezoelectric bimorph element  2525   g  and a high-end piezoelectric bimorph element  2525   h  are respectively bonded directly to the inside of the cartilage conduction unit  5824   c , such that the vibrating surface side thereof is in contact therewith. In so doing, vibration of the piezoelectric bimorph element  2525   g  and the piezoelectric bimorph element  2525   h  is transmitted directly to the cartilage conduction unit  5824   c . In this way, through the complementary use of multiple cartilage conduction vibration sources of different frequency characteristics, the frequency characteristics of cartilage conduction can be improved. 
     In the modification examples of  FIG. 94(B)  to  FIG. 94(D) , the convex-faced cartilage conduction unit is of conical (cone) shape. By adopting such a configuration, the side surface of the conical element (cone) fits into the external auditory meatus, irrespective of individual differences in the size of the external auditory meatus, so that cartilage conduction from the entire circumference of the external auditory meatus can be achieved. 
     Sixty-Third Embodiment 
       FIG. 95  is a cross sectional view relating to a sixty-third embodiment according to an aspect of the present invention, which is configured as stereo headphones  5981 .  FIG. 95(A)  is a cross sectional view of the stereo headphones  5981  in their entirety, which have a right ear cartilage conduction unit  5924  and a left ear cartilage conduction unit  5926 . The right ear cartilage conduction unit  5924  and the left ear cartilage conduction unit  5926  are respectively of conical (cone) convex shape. A piezoelectric bimorph element  2525   i  and a piezoelectric bimorph element  2525   j  are respectively bonded to the inside of the right ear cartilage conduction unit  5924 , such that the vibrating surface side thereof is in contact therewith. This construction is basically one shared with the third modification example of the sixty-second embodiment in  FIG. 94(D) . Likewise, a piezoelectric bimorph element  2525   k  and a piezoelectric bimorph element  2525   m  are respectively bonded to the inside of the left ear cartilage conduction unit  5926 , such that the vibrating surface side thereof is in contact therewith. 
       FIG. 95(B)  and  FIG. 95(C)  describe a feature whereby, by adopting a convex face of conical (cone) shape for the right ear cartilage conduction unit  5924  (and the left ear cartilage conduction unit  5926 ), the right ear cartilage conduction unit  5924  (and the left ear cartilage conduction unit  5926 ) can be made to fit into an external auditory meatus  30   a , irrespective of individual differences in the size of the external auditory meatus  30   a ; and respectively show a representative enlarged section of the right ear cartilage conduction unit  5924  in the sixty-third embodiment.  FIG. 95(B)  shows a case of use of the stereo headphones  5981  by an individual whose external auditory meatus  30   a  is relatively small, in which case a section comparatively towards the distal end of the conical element of the right ear cartilage conduction unit  5924  contacts the entire circumference of the external auditory meatus  30   a . In contrast to this,  FIG. 95(C)  shows a case of use of the stereo headphones  5981  by an individual whose external auditory meatus  30   a  is relatively large, in which case the conical element of the right ear cartilage conduction unit  5924  slips more deeply into the external auditory meatus, so that a section comparatively towards the basal end of the conical element contacts the entire circumference of the external auditory meatus  30   a . However, as will be clear from an examination of  FIG. 95(B)  and  FIG. 95(C) , the depth to which the conical element of the right ear cartilage conduction unit  5924  slips into external auditory meatus  30   a  has no significant effect on cartilage conduction, and by adopting a conical shape for the right ear cartilage conduction unit  5924 , the right ear cartilage conduction unit  5924  can be made to unfailingly contact the entire circumference of the external auditory meatus  30   a  in satisfactory fashion, irrespective of individual differences in the size of the external auditory meatus  30   a . Like the right ear cartilage conduction unit  5924 , the left ear cartilage conduction unit  5926  will also be made to contact the entire circumference of the external auditory meatus  30   a  in satisfactory fashion, irrespective of individual differences in the size of the external auditory meatus  30   a.    
     By configuring a stereo audio output device by using a pair of sound output devices like those of the sixty-third embodiment, having a cartilage conduction unit with a convex face of conical shape, and a cartilage conduction vibration source for transmitting vibration to the cartilage conduction unit, the cartilage conduction units can be slipped in from the left and the right and pressed respectively into the external auditory meatus of each ear, whereby satisfactory contact of the convex face of conical shape of the cartilage conduction unit against the entire circumference of the external auditory meatus can be achieved. 
     In the sixty-third embodiment, the conical elements of the right-ear cartilage conduction unit  5924  and the left-ear cartilage conduction unit  5926  are configured with an obtuse angle like that in the third modification example of the sixty-second embodiment in  FIG. 94(D) ; however, a configuration having an acute angle would be acceptable if needed. In this case, the distal end would be rounded to avoid posing any danger. In the sixty-third embodiment, two piezoelectric bimorph elements each having identical frequency characteristics are bonded to the right-ear cartilage conduction unit  5924  and the left-ear cartilage conduction unit  5926 ; however, ones having different frequency characteristics, like those in the third modification example of the sixty-second embodiment in  FIG. 94(D) , would be acceptable as well. A configuration in which the right-ear cartilage conduction unit  5924  and the left-ear cartilage conduction unit  5926  are each furnished with a single piezoelectric bimorph element would be acceptable as well. In this case, instead of direct adhesion, a configuration in which the element is supported via the vibration conductor, as in the sixty-second embodiment and modification examples thereof in  FIG. 94(A)  to  FIG. 94(C) , would also be acceptable. 
     The features of the several inventions described above are not limited to the aforedescribed embodiments, and implementation in other embodiments is possible. For example, in the aforedescribed sixty-second embodiment and sixty-third embodiment, it would be possible to adopt, as the cartilage conduction vibration source thereof, another vibration source such as an electromagnetic vibrator of the sort shown in other aforedescribed embodiments, instead of piezoelectric bimorph elements. Moreover, whereas the aforedescribed sixty-second embodiment described configuration as a handset of a land-line telephone, and the aforedescribed sixty-third embodiment as headphones, respectively, implementation of the features described above is not limited to these. That is, it is possible for the various features described in relation to providing a convex face to the cartilage conduction vibration unit in the aforedescribed embodiments to be implemented, for example, in a configuration for earphones or in a configuration for a headset, as shown in other aforedescribed embodiments. Implementation in a land-line telephone is not limited to the features shown in the aforedescribed sixty-second embodiment, and it is possible for various features which are shown in yet other embodiments by way of an embodiment such as a mobile telephone, to be implemented in the handset of a land-line telephone, as appropriate. 
     Sixty-Fourth Embodiment 
       FIG. 96  is a perspective view, a cross sectional view, and a top view relating to a sixty-fourth embodiment according to an aspect of the present invention, configured as a mobile telephone  6001 . The sixty-fourth embodiment has much in common with the fifty-fifth embodiment shown in  FIG. 83 , except for the holding structure of the cartilage conduction unit  2525  (hereinafter denoted as piezoelectric bimorph element  2525 ) which is constituted by a piezoelectric bimorph element; therefore corresponding portions have been given like reference numerals, and a description has been omitted unless necessary. 
     In the sixty-fourth embodiment of  FIG. 96 , as in the fifty-fifth embodiment of  FIG. 83 , the main vibration direction of the piezoelectric bimorph element  2525  is oriented orthogonal to a GUI display unit  3405 , and features a characteristic holding structure.  FIG. 96(A)  is a perspective view of the mobile telephone  6001  of the sixty-fourth embodiment seen from the front face; the structure for holding the piezoelectric bimorph element  2525  is produced by integral molding of a right-ear cartilage conduction unit  6024 , a left-ear cartilage conduction unit  6026 , and a linking unit  6027  linking these, from a hard material. The piezoelectric bimorph element  2525  is supported at the inside of the right-ear cartilage conduction unit  6024 , whereby it is possible for vibration thereof to be transmitted directly to the right ear cartilage contacted by the right-ear cartilage conduction unit  6024 . Further, vibration of the piezoelectric bimorph element  2525  supported by the right-ear cartilage conduction unit  6024  is transmitted as well to the left-ear cartilage conduction unit  6026  through the linking unit  6027  which serves as a vibration conductor, whereby it is possible to achieve cartilage conduction, without the left-ear cartilage conduction unit  6026  contacting the left ear cartilage. 
     Further, the aforedescribed hard, integrally molded structure is attached to the chassis of the mobile telephone  6001  via an elastic body  6065  made of ethylene resin, urethane resin, or the like, so that the hard, integrally molded structure directly contacts the chassis of the mobile telephone  6001 . Consequently, the elastic body  6065  functions as a vibration isolating material and a cushioning material, and also mitigates transmission of vibration of the piezoelectric bimorph element  2525  to the chassis of the mobile telephone  6001 . In so doing, the risk of bothering people nearby, or loss of privacy, due to audible receiver sounds caused by air-conducted sound generated by vibration of the chassis of the mobile telephone  6001  can be prevented. Moreover, because the elastic body  6065  transmits vibration for the purpose of cartilage conduction, good cartilage conduction can be obtained even when the front surface side of a corner of the elastic body  6065  is placed against the ear cartilage. 
       FIG. 96(B)  is a top cross sectional view of the mobile telephone  6001  taken in the B 1 -B 1  cross section in  FIG. 96(A)  (a cross section of the mobile telephone  6001  cut through the center).  FIG. 96(B)  shows a top center cross section, from which it may be appreciated that the piezoelectric bimorph element  2525  is supported in cantilever fashion to the inside of the right-ear cartilage conduction unit  6024  in the integrally molded structure, with the side thereof at which a terminal  2525   b  is furnished serving as the held end. While the details of the structure are omitted from the illustration, the inside of the right-ear cartilage conduction unit  6024 , which holds the piezoelectric bimorph element  2525  via the terminal  2525   b , is provided with a connection space and a connecting wire leadout slot therefor. 
     Meanwhile, as will be clear from  FIG. 96(B) , the other end  2525   c  of the piezoelectric bimorph element  2525  is a free vibrating end, to which an inertial weight (inertial bob)  6025  has been attached. The inertial weight  6025  increases the eight of the other end  2525   c , thereby suppressing movement of the other end  2525   c  through inertia, and increasing the vibration energy drawn from the held end side through vibration of the piezoelectric bimorph element  2525  as counteraction thereof. Stated another way, the held end side of the piezoelectric bimorph element  2525  increases the component that vibrates together with the hard, integrally molded structure with the inertial weight  6025  side as the fulcrum point. 
     Moreover, as will be clear from  FIG. 96(B) , the linking unit  6027  is thinner than the right-ear cartilage conduction unit  6024  and the left-ear cartilage conduction unit  6026 , so that the right-ear cartilage conduction unit  6024  and the left-ear cartilage conduction unit  6026  are linked in “shoulder pole” fashion so as to bypass the internal components of the mobile telephone  6001 . In so doing, it is possible to devise a layout for an in-camera  6017  and the like, which are preferably situated in the upper part of the mobile telephone  6001 . The thickness of the linking unit  6027  need merely be one sufficient to achieve rigid fastening of the positional relationships of the right-ear cartilage conduction unit  6024  and the left-ear cartilage conduction unit  6026 , so linking structures other than that shown in  FIG. 96  are possible. Moreover, seen from the standpoint of functionality as a cartilage conduction unit as well, it is sufficient for the linking unit  6027  to have a relatively small cross sectional area, and therefore there is a greater degree of freedom in relation to placement of components inside the mobile telephone  6001  in relation to the linking unit  6027 . 
       FIG. 96(C)  is an exterior view of the mobile telephone  6001  seen from the top face, in which the integrally molded structure including the right-ear cartilage conduction unit  6024 , the left-ear cartilage conduction unit  6026 , and the linking unit  6027  linking these is exposed. An elastic body  6065  sandwiching these from both sides is exposed as well. In  FIG. 96(C) , the interrelationships of the internal piezoelectric bimorph element  2525 , the inertial weight  6025 , and the in-camera  6017 , as well as the boundary lines of the right-ear cartilage conduction unit  6024 , the linking unit  6027 , and the left-ear cartilage conduction unit  6026 , are shown by broken lines. 
       FIG. 96(D)  is an upper part cross sectional side view of the mobile telephone  6001  taken in the B 2 -B 2  cross section in  FIG. 96(A) -(C). In this cross sectional side view as well, the right-ear cartilage conduction unit  6024  is attached to the chassis of the mobile telephone  6001  via the elastic body  6065  serving as an isolating material and a cushioning material, so as to have no direct contact with the mobile telephone  6001  chassis. 
     Sixty-Fifth Embodiment 
       FIG. 97  is a perspective view, a cross sectional view, and a top view of a sixty-fifth embodiment according to an aspect of the present invention, configured as a mobile telephone  6101 . The sixty-fifth embodiment has much in common with the sixty-fourth embodiment of  FIG. 96 , except for a different shape for a right-ear cartilage conduction unit  6124 , a left-ear cartilage conduction unit  6126 , and a linking unit  6127 , and in association therewith, a different shape for an elastic body  6165 . Therefore, the discussion focuses mainly on the different portions, assigning like symbols to and the common portions and omitting descriptions thereof unless necessary. 
     From the perspective view in  FIG. 97(A)  it will be clear that in the sixty-fifth embodiment, the right-ear cartilage conduction unit  6124 , the left-ear cartilage conduction unit  6126 , and the linking unit  6127  linking these are integrally molded from hard material, to a shape covering the upper part of the mobile telephone  6101 . In association therewith, the elastic body  6165  is interposed at a location sandwiched vertically between the integrally molded structure and the chassis of the mobile telephone  6101 , so that there is no direct contact between the two. 
       FIG. 97(B)  is an upper part cross sectional view of the mobile telephone  6101  in the B 1 -B 1  cross section in  FIG. 97(A) . Because the B 1 -B 1  cross section is a cross section taken of the mobile telephone  6101  cut from the center, there is basically no difference from the sixty-fourth embodiment of  FIG. 96(B) ; however, when the B 1 -B 1  cross section is shifted in parallel fashion to approach towards the front surface side or the back face side of the mobile telephone  6101 , the resultant cross section differs from the sixty-fourth embodiment of  FIG. 96 , as will be clear from  FIG. 97(A) . As will be appreciated from  FIG. 97(B) , in the sixty-fifth embodiment, the piezoelectric bimorph element  2525  is supported in cantilever fashion to the inside of the right-ear cartilage conduction unit  6124 , with an end part  2525   c  not furnished with a terminal  2525   c  serving as the held end. Meanwhile, the end part of the piezoelectric bimorph element  2525  where the terminal  2525   b  is furnished constitutes a free vibrating end, to which an inertial weight  6125  is attached. While the details of the structure are omitted from the illustration, the piezoelectric bimorph element  2525  is attached via the terminal  2525   b  to the inside of the inertial weight  6125 , which is provided with a connection space and a connecting wire leadout slot therefor. Selection of the held end and the inertial weight attachment end in this manner is not a characteristic feature of the sixty-fifth embodiment, and the attachment method of the sixty-fifth embodiment may be adopted in the sixty-fourth embodiment, or vice-versa. 
     As will be clear from  FIG. 97(B) , in the sixty-fifth embodiment as well, the linking unit  6127  is thinner than the right-ear cartilage conduction unit  6124  and the left-ear cartilage conduction unit  6126 , so that the right-ear cartilage conduction unit  6124  and the left-ear cartilage conduction unit  6126  are linked in “shoulder pole” fashion to bypass the internal components of the mobile telephone  6101 . In the sixty-fifth embodiment, it is possible in terms of strength for the linking unit  6127  to be even thinner, as the linking unit  6127  has considerable width and covers the entire top face. Further, depending on the design, it is possible to configure the linking unit  6127  to cover not only the top face, but also to wrap around to the front surface side and the back face side, so that the linking unit  6127  can be even thinner. 
       FIG. 97(C)  is an exterior view of the mobile telephone  6101  seen from the top face, in which the integrally molded structure including the right-ear cartilage conduction unit  6124 , the left-ear cartilage conduction unit  6126 , and the linking unit  6127  linking these is visible. In  FIG. 97(C)  as well, the interrelationships of the internal piezoelectric bimorph element  2525 , an inertial weight  6125 , and an in-camera  6117 , as well as the boundary lines of the right-ear cartilage conduction unit  6124 , the linking unit  6127 , and the left-ear cartilage conduction unit  6126 , are shown by broken lines. 
       FIG. 97(D)  is an upper part cross sectional side view of the mobile telephone  6101  taken in the B 2 -B 2  cross section in  FIG. 97(A) -(C). In the cross sectional side view of the sixty-fifth embodiment as well, the right-ear cartilage conduction unit  6124  is attached to the chassis of the mobile telephone  6101  via an elastic body  6165  serving as an isolating material and a cushioning material, so as to have no direct contact with the mobile telephone  6101  chassis. 
     Sixty-Sixth Embodiment 
       FIG. 98  is a perspective view, a cross sectional view, and a top view relating to a sixty-sixth embodiment according to an aspect of the present invention, configured as a mobile telephone  6201 . The sixty-sixth embodiment likewise has much in common with the sixty-fourth embodiment of  FIG. 96  and the sixty-fifth embodiment of  FIG. 97 , except for a different shape for a right-ear cartilage conduction unit  6224 , a left-ear cartilage conduction unit  6226 , and a linking unit  6227 , and in association therewith, a different shape for an elastic body  6265 . Therefore, the discussion focuses mainly on the different portions, assigning like symbols to and the common portions and omitting descriptions thereof unless necessary. 
     From the perspective view in  FIG. 98(A)  it will be clear that in the sixty-sixth embodiment, the right-ear cartilage conduction unit  6224  and the left-ear cartilage conduction unit  6226  are exposed to the outside, while the linking unit  6227  which links these inside the chassis is not visible from the outside. In association therewith, from the outside, the elastic body  6265  is visible only in portions isolating the right-ear cartilage conduction unit  6224  and the left-ear cartilage conduction unit  6226  from the chassis of the mobile telephone  6201 , and there is no direct contact between the right-ear cartilage conduction unit  6224  and the left-ear cartilage conduction unit  6226  and the chassis of the mobile telephone  6201 . Consequently, the sixty-sixth embodiment may be said to have an external appearance in common with that of the fifty-fifth embodiment of  FIG. 83 , albeit in relation to the external appearance only. The internal structure does differ however, in the manner described below. 
       FIG. 98(B)  is an upper part cross sectional side view of the mobile telephone  6201  taken in the B 1 -B 1  cross section in  FIG. 98(A) . From  FIG. 98(B) , it will be clear that in the sixty-sixth embodiment, the right-ear cartilage conduction unit  6224  and the left-ear cartilage conduction unit  6226  are linked inside the chassis by the linking unit  6227 . The linking unit  6227  does not contact the chassis interior. A function of transmitting to the left-ear cartilage conduction unit  6226  the vibration of the right-ear cartilage conduction unit  6224  which supports the piezoelectric bimorph element  2525 , and a function of rigid integration of the right-ear cartilage conduction unit  6224  and the left-ear cartilage conduction unit  6226 , are possible with the linking unit  6227  inside the chassis as in the sixty-sixth embodiment. 
       FIG. 98(C)  is an exterior view of the mobile telephone  6201  from the top face; at both corners in the upper part of the mobile telephone  6201 , the elastic body  6265  is visible, blocking the right-ear cartilage conduction unit  6224  and the left-ear cartilage conduction unit  6226 , respectively, as well as vibration thereof, from the chassis. In  FIG. 98(C)  as well, the interrelationships of the internal piezoelectric bimorph element  2525 , an inertial weight  6225 , an in-camera  6217 , and the linking unit  6227  are shown by broken lines. 
       FIG. 98(D)  is an upper part cross sectional side view of the mobile telephone  6201  taken in the B 1 -B 1  cross section in  FIG. 98(A) -(C) The cross sectional side view of the ninety-eighth embodiment is basically no different from the sixty-fifth embodiment of  FIG. 97(B) ; however, when the B 2 -B 2  cross section is shifted in parallel fashion to approach towards the center side from a side surface of the mobile telephone  6201 , the resultant cross section differs from the sixty-fifth embodiment of  FIG. 97 , as is clear from  FIG. 98(A) . 
     In the sixty-fourth to sixty-sixth embodiments of the preceding  FIGS. 96 to 98 , the main vibration direction of the piezoelectric bimorph element  2525  was described as being oriented orthogonal to the GUI display unit  3405 . However, the orientation at which the piezoelectric bimorph element  2525  is held in these embodiments is not limited to this, and the main vibration direction of the piezoelectric bimorph element  2525  may be oriented parallel to the GUI display unit  3405  (the vertical direction of the mobile telephone). Setting of the main vibration direction of the piezoelectric bimorph element  2525  is accomplished in the manner discussed in detail previously in the fifty-sixth embodiment of  FIG. 86  in relation to the fifty-fifth embodiment of  FIG. 83 . 
     Sixty-Seventh Embodiment 
       FIG. 99  is a perspective view and a cross sectional view relating to a sixty-seventh embodiment according to an aspect of the present invention, configured as a mobile telephone  6301 . In the sixty-seventh embodiment, the structure of the sixty-sixth embodiment of FIG.  98 , in which the right-ear cartilage conduction unit and the left-ear cartilage conduction unit are rigidly linked by a linking unit, is applied in the fifty-fifth embodiment of  FIG. 83 ; however, other features are common to both, and therefore these common portions have been assigned the same symbols as in the fifty-fifth embodiment of  FIG. 83 , omitting descriptions thereof unless necessary. 
     As will be clear from  FIG. 99(B) , in the sixty-seventh embodiment, a right-ear cartilage conduction unit  6324  and a left-ear cartilage conduction unit  6326  are linked rigidly into an integrated body inside the chassis by a linking unit  6327 . The linking unit  6327  does not contact the chassis interior. This feature of the sixty-seventh embodiment may be said to belong in common to the sixty-sixth embodiment of  FIG. 98 . However, viewed in terms of functionality, in the sixty-seventh embodiment of  FIG. 99 , vibration of the piezoelectric bimorph element  2525  is transmitted directly to the right cartilage conduction unit  6324  and the left cartilage conduction unit  6326 , respectively, and in this sense alone, the vibration transmission path afforded by the linking unit  6327  is redundant. 
     However, even in cases in which, as the sixty-seventh embodiment, it is not necessary to transmit vibration between the right cartilage conduction unit  6324  and the left cartilage conduction unit  6326 , integration of the two by the linking unit  6327  is highly significant in terms of achieving stable attachment to the chassis. To describe in more specific terms, ordinarily, when an elastic body  6365  disposed between the chassis, and the right cartilage conduction unit  6324  and the left cartilage conduction unit  6326 , is made softer or thicker in order to suppress transmission of vibration between the two, the result of doing so is that the hold of the right cartilage conduction unit  6324  and the left cartilage conduction unit  6326  on the chassis becomes unstable. In contrast to this, when the right cartilage conduction unit  6324  and the left cartilage conduction unit  6326  are rigidly linked by the linking unit  6327  as in the sixty-seventh embodiment, the relative positions of both are maintained, so that both can be more stably attached to the chassis, even when the elastic body  6365  is made softer or thicker. 
     Sixty-Eighth Embodiment 
       FIG. 100  is a cross sectional view relating to a sixty-eighth embodiment according to an aspect of the present invention, configured as a mobile telephone  6401 . In the sixty-eighth embodiment, the structure of the sixty-fifth embodiment of  FIG. 97 , in which the right-ear cartilage conduction unit and the left-ear cartilage conduction unit are rigidly linked by a linking unit, is applied in the fifty-second embodiment of  FIG. 77 ; however, other features are shared by both, and therefore these common portions have been assigned the same symbols as in the fifty-second embodiment of  FIG. 77 , omitting descriptions thereof unless necessary. 
     In the sixty-eighth embodiment of  FIG. 100 , in the same manner as in the sixty-fifth embodiment of  FIG. 97 , a right-ear cartilage conduction unit  6424 , a left-ear cartilage conduction unit  6426 , and a linking unit  6427  linking these are integrally molded from a hard material, to a shape covering the upper part of the mobile telephone  6401 . An elastic body  6465  is interposed at a location sandwiched vertically between this integrally molded structure and the chassis of the mobile telephone  6401 , so that there is no direct contact between the two. A right-ear piezoelectric bimorph element  2525   q  is attached to the right-ear cartilage conduction unit  6424 , and a left-ear piezoelectric bimorph element  2525   p  to the left-ear cartilage conduction unit  6426 , respectively, doing so such that the elements are supported at one side thereof by a cantilever structure. As in the seventy-seventh embodiment, the right-ear piezoelectric bimorph element  2525   q  and the left-ear piezoelectric bimorph element  2525   p  are controllable in mutually independent fashion. 
     In the sixty-eighth embodiment of  FIG. 100 , in the same manner as in the sixty-seventh embodiment of  FIG. 99 , the primary significance of the linking unit  6427  is to rigidly link the right-ear cartilage conduction unit  6424  and the left-ear cartilage conduction unit  6326 , to maintain the relative positions of both, so that both can be attached in a more stable manner to the chassis, even when the elastic body  6465  is made softer or thicker. 
     In the sixty-eighth embodiment of  FIG. 100 , further, vibration of the left-ear piezoelectric bimorph element  2525   p  is transmitted towards the direction of the right-ear cartilage conduction unit  6424 , and vibration of the right-ear piezoelectric bimorph element  2525   q  is transmitted towards the direction of the left-ear cartilage conduction unit  6426 , via the linking unit  6427 . In this manner, in the sixty-eighth embodiment, vibration of the left-ear piezoelectric bimorph element  2525   p  and vibration of the right-ear piezoelectric bimorph element  2525   q  become admixed within the integrally molded structure of the right-ear cartilage conduction unit  6424 , the left-ear cartilage conduction unit  6426 , and the linking unit  6427  linking these. As a result, when vibrations of mutually reversed waveform are generated by the left-ear piezoelectric bimorph element  2525   p  and the right-ear piezoelectric bimorph element  2525   q , the vibrations cancel out each other within the integrally molded structure, suppressing the occurrence of air-conducted sound based on vibration transmitted from the integrally molded structure to the chassis of the mobile telephone  6401 . In this state as well, when either the right-ear cartilage conduction unit  6424  or the left-ear cartilage conduction unit  6426  is placed in contact with ear cartilage, the vibration of the right-ear piezoelectric bimorph element  2525   q  or the right-ear piezoelectric bimorph element  2525   p , which are directly held thereby, will be greater than the vibration traveling through the linking unit  6427 , and therefore the differential thereof will be conducted to the ear cartilage in satisfactory fashion. 
     The various features shown in the preceding embodiments are not limited to implementation in the respective embodiments, and implementation in various other embodiments is possible. For example, by modifying the sixty-eighth embodiment of  FIG. 100  to omit the right-ear piezoelectric bimorph element  2525   q , implementation in accordance with the sixty-fifth embodiment of  FIG. 97  is possible. Stated another way, because vibration of the piezoelectric bimorph element  2525   p , which is supported by the left-ear cartilage conduction unit  6426 , is transmitted to the right-ear cartilage conduction unit  6424  as well through the linking unit  6427 , it is possible to achieve good cartilage conduction, despite the fact that the right-ear cartilage conduction unit  6424 , which does not hold a piezoelectric bimorph element, is placed in contact against the cartilage of the right ear. As may be seen from this modification example, the arrangement for holding the cartilage conduction vibration source which transmits vibration through the linking unit is not limited to an arrangement in which the piezoelectric bimorph element  2525  is held in a sideways long direction as in the sixty-fifth embodiment of  FIG. 97 , and it would be possible for the piezoelectric bimorph element  2525   p  to be held in a vertical long direction as in the aforedescribed modification example of the sixty-eighth embodiment of  FIG. 100 . These are merely examples, and it would be possible for cartilage conduction vibration sources to be to arranged and held in any of various other formats and orientations, according to the layout of the various components inside the mobile telephone. 
     Sixty-Ninth Embodiment 
       FIG. 101  is a system configuration diagram and a usage description diagram of a sixty-ninth embodiment according to an aspect of the present invention. As shown in  FIG. 101(A) , the sixty-ninth embodiment is constituted as a mobile telephone system comprising an ordinary mobile telephone  1601 , and an ultra-compact mobile telephone  6501  having a cartilage conduction unit  6524 . The two are capable of short-range communication by radio waves  6585  of a communication system such as Bluetooth™ or the like. The mobile telephone system of the sixty-ninth embodiment has much in common with the sixteenth embodiment of  FIG. 27  and  FIG. 28  and with the seventeenth embodiment shown in the block diagram of  FIG. 29 . Therefore, the description of the sixty-ninth embodiment, as relates to the external appearance, is based on  FIG. 27 ; and in as relates to the internal configuration, is based on the block diagram of  FIG. 29 , assigning the same reference numerals to the common portions, and omitting descriptions unless necessary. 
     As mentioned above, the sixty-ninth embodiment of  FIG. 101  differs from the sixteenth embodiment and the seventeenth embodiment in that a cartilage conduction output portion capable of short-range communication with the ordinary mobile telephone  1601  is constituted as the ultra-compact mobile telephone  6501  which is capable of functioning independently. It is possible, using the ultra-compact mobile telephone  6501 , to make call operations directed to the ordinary mobile telephone, through an operating unit  6509  and a display unit  6505 . The characteristic features of this embodiment reside in the outgoing-talk unit and the incoming-talk unit thereof. First, with regard to the incoming-talk unit, the cartilage conduction unit  6524  is situated in a corner of the upper part of the ultra-compact mobile telephone  6501 , and a piezoelectric bimorph element  2525  is held in cantilever fashion in a longitudinal direction in the interior thereof. In this sense, the configuration of the ultra-compact mobile telephone  6501  of the sixty-ninth embodiment is shared with the forty-third embodiment of the  FIG. 66 . Meanwhile, the outgoing-talk unit is furnished with a contact type bone conduction microphone  6523  situated close to a corner of the lower part of the ultra-compact mobile telephone  6501 . The ultra-compact mobile telephone  6501  is used by placing the cartilage conduction unit  6524  in contact with the ear cartilage of the tragus or the like, while placing the bone conduction microphone  6523  against the cheekbone or lower jawbone. 
       FIG. 101(B)  shows a state in which, just as shown in  FIG. 2(A) , the cartilage conduction unit  6524  is placed in contact with the ear cartilage of the tragus or the like, with the display unit  6505  oriented to face the cheek, and the bone conduction microphone  6523  is placed against the cheekbone. In  FIG. 101(B) , the cartilage conduction unit  6524  and the bone conduction microphone  6523  are illustrated in order to show their vertical positional relationships; however, in the case of usage as shown in the drawing, these would be positioned to the rear, and therefore would not actually be visible from the front. 
     Meanwhile,  FIG. 101(C)  shows a state in which, just as shown in  FIG. 21(A) , the cartilage conduction unit  6524  is placed in contact with the ear cartilage of the tragus or the like, from the side surface side with the display unit  6505  oriented to face frontward, and the bone conduction microphone  6523  is placed against the cheekbone. Due to the small size of the ultra-compact mobile telephone  6501  of the sixty-ninth embodiment, the ultra-compact mobile telephone  6501  can be used in whichever direction is easiest to hold, either as shown above in  FIG. 101(B)  or  FIG. 101(C) . When used as shown in  FIG. 101(C) , by taking care not to grip the display screen  6505  with the fingers, soiling of the display screen  6505  due to contact of the display screen  6505  against the cheek can be prevented. By varying the angle at which the ultra-compact mobile telephone  6501  is placed against the face, the bone conduction microphone  6523  can also be positioned against the upper part of the lower jawbone while keeping the cartilage conduction unit  6524  in contact with the ear cartilage of the tragus or the like. 
     Because the ordinary mobile telephone  1601  and the ultra-compact mobile telephone  6501  each have separate phone numbers, it is possible for them to be used independently from one another. Pairing of the ordinary mobile telephone  1601  and the ultra-compact mobile telephone  6501  by short-range communication will be described next. The ordinary mobile telephone  1601 , due to its size, is not infrequently stowed inside a purse or the like when not being used, while the ultra-compact mobile telephone  6501  can be easily placed in a shirt pocket or the like, and kept in possession at all times. 
     In a first example of pairing of the two devices, the ultra-compact mobile telephone  6501 , while kept in possession in the aforedescribed manner, may be used as an incoming call vibrator for the ordinary mobile telephone  1601 . That is, when there is an incoming call to the ordinary mobile telephone  1601 , it is transferred to the ultra-compact mobile telephone  6501  through the radio waves  6585  of the short-range wireless system, whereupon the ultra-compact mobile telephone  6501  is operated as a incoming call vibrator, and can reliably alert the user of an incoming call to the ordinary mobile telephone  1601  which is being carried in a purse or the like. In the sixty-ninth embodiment, a dedicated incoming call vibrator, such as an eccentric motor, is employed as the incoming call vibrator of the ultra-compact mobile telephone  6501 ; however, as will be discussed below, it is possible for the cartilage conduction vibration unit to be vibrated to be employed concomitantly as an incoming call vibrator, as shown in the thirteenth embodiment. 
     In a second example of pairing of the two devices, the ultra-compact mobile telephone  6501 , while kept in possession in the aforedescribed manner, may be used as a handset for the ordinary mobile telephone  1601 . That is, when there is an incoming call to the ordinary mobile telephone  1601 , it is transferred to the to the ultra-compact mobile telephone  6501  through the radio waves  6585  of the short-range wireless system, whereupon after call answer operation has been performed on the ultra-compact mobile telephone  6501 , it possible for the call to take place through the cartilage conduction unit  6524  and the bone conduction microphone  6523 . In so doing, it is possible for a call to take place in a manner taking full advantage of cartilage conduction in the ordinary mobile telephone  1601 . Naturally, the ordinary mobile telephone  1601  may remain in the purse or the like at this time. 
     In a third example of pairing of the two devices, the ultra-compact mobile telephone  6501  may be used as a handset when the ordinary mobile telephone  1601  is in videoconferencing mode. In videoconferencing mode, conversation takes place with the ordinary mobile telephone  1601  held away from the face, and therefore there is a considerable distance from microphone to mouth, and also the voice of the other caller is output from a speaker situated away from the ear; thus, from an acoustic standpoint, there are numerous problems in terms of the effects of noise, loss of privacy, and the like. In contrast to this, by using the ultra-compact mobile telephone  6501  as a handset, it is possible for a call to take place in a manner that takes full advantage of cartilage conduction, with the ordinary mobile telephone  1601  in videoconferencing mode. The details of the above pairing will be discussed below. 
       FIG. 102  is a block diagram of the sixty-ninth embodiment, in which like portions are assigned the same symbols as in  FIG. 101 . As described above, the block diagram of  FIG. 102  has much in common with the block diagram of  FIG. 29 , and therefore the same reference numerals as those assigned to these parts have been assigned to the corresponding portions. In particular, the ordinary mobile telephone  1601  in  FIG. 102  has the same configuration as in in  FIG. 29 . However, a portion of the configuration is omitted in  FIG. 102 . For convenience in description, the ordinary mobile telephone  1601 , which is depicted as being situated at the top in  FIG. 29 , is depicted as being situated at the bottom in  FIG. 102 . 
     When there is an incoming call to the ordinary mobile telephone  1601 , this is transferred from a short-range communication unit  1446  to a short-range communication unit  6546  by the radio waves  6585 , whereupon a controller  6539  prompts an incoming call vibrator  6525  to vibrate according to a pre-established ordinary mobile telephone incoming call alert pattern. The controller  6539  also prompts the display unit  6505  to display an alert of an incoming call to the ordinary mobile telephone  1601 . 
     When a call answer operation is input from the operating unit  6509 , this is transferred from the short-range communication unit  6546  to the short-range communication unit  1446  by the radio waves  6585 , whereupon a controller  239  of the ordinary mobile telephone  1601  initiates the call by a telephone function unit  45 . In so doing, an incoming-talk tone signal is transferred from an incoming-talk processing unit  212  of the ordinary mobile telephone  1601  to the short-range communication unit  6546  of the ultra-compact mobile telephone  6501  via the short-range communication unit  1446 . In response to this, the incoming-talk processing unit  6512  of the ultra-compact mobile telephone  6501  prompts the cartilage conduction unit  6524  to vibrate. Meanwhile, an outgoing-talk tone picked up by the bone conduction microphone  6523  is transferred from an outgoing-talk processing unit  6522  of the ultra-compact mobile telephone  6501  to the short-range communication unit  1446  of the ordinary mobile telephone  1601  via the short-range communication unit  6546 . In response, the ordinary mobile telephone  1601  transmits an outgoing-talk tone signal via a telephone communication unit  47 . 
     On the other hand, when there is an incoming call to the ultra-compact mobile telephone  6501 , the controller  6539  prompts the incoming call vibrator  6525  to vibrate according to a pre-established ultra-compact mobile telephone incoming call alert pattern. The controller  6539  also prompts the display unit  6505  to display an alert of an incoming call to the ultra-compact mobile telephone  6501 . 
     When a call answer operation is performed from the operating unit  6509 , the controller  6539  initiates the call through a telephone communication unit  6545 . In so doing, the incoming-talk processing unit  6512  prompts the cartilage conduction unit  6524  to vibrate in response to the incoming-talk signal received by the telephone communication unit  6547 . Meanwhile, on the basis of the outgoing-talk tone picked up by the bone conduction microphone  6523 , the outgoing-talk processing unit  6522  transmits an outgoing-talk tone signal via the telephone communication unit  6547 . 
     By establishing different vibration patterns for the incoming call vibrator  6525  in the above manner, it is possible to distinguish which device is being called. Additionally, the device being called is displayed on the display unit  6505  in the aforedescribed manner. Regardless of which device is called, call reception can be initiated by the same operation to the operating unit  6509  in the aforedescribed manner. As in the other embodiments, the controller  6539  operates according a program stored in a memory unit  6537 . The memory unit  6537  can temporarily store data necessary for control by the controller  6539 , as well as store measurement data and images of various kinds. A power supply unit  6548  supplies each part of the ultra-compact mobile telephone  6501  with the necessary power. 
     Seventieth Embodiment 
       FIG. 103  is a perspective view of a seventieth embodiment according to an aspect of the present invention, constituted as a mobile telephone  6601 . The mobile telephone  6601  of the seventieth embodiment has much in common with the mobile telephone system of the sixty-ninth embodiment in  FIG. 101  and  FIG. 102 , and therefore the same reference numerals are assigned to the common portions, omitting descriptions unless necessary. 
     A point of difference between the seventieth embodiment of  FIG. 103  and the sixty-ninth embodiment is that the short-range communication-enabled cartilage conduction output portion, rather than being configured as a mobile telephone capable of functioning independently, is instead configured as an outgoing-talk/incoming-talk unit that is part of the mobile telephone  6601 . In this sense, the configuration of the seventieth embodiment is shared with that of the thirteenth embodiment of  FIG. 24 . The following specific description is based on  FIG. 103 . 
     As shown in  FIG. 103(A) , a mobile telephone  6601  comprises a mobile telephone lower part  6601   a  and a mobile telephone upper part  6601   b , the two being separable. An appropriate known means, such as a planar fastener, mating structure, or the like, is utilized for joining and separation of the mobile telephone lower part  6601   a  and the mobile telephone upper part  6601   b . As in other embodiments, the mobile telephone upper part  6601   b  is furnished with a cartilage conduction unit  6626  situated in a corner of the upper portion of the mobile telephone  6601 , in the interior of which a piezoelectric bimorph element  2525  is held in cantilever fashion in a lateral/longitudinal direction. This structure is shared with the forty-second embodiment of  FIG. 65 , but with the left-right orientation reversed. On the one hand, the incoming-talk unit is furnished with a contact type bone conduction microphone  6523  situated close to the other corner of the upper part of the mobile telephone  6601 . An upper part operating unit  6609  is used to perform call answer operation and the like, while separated from the mobile telephone lower part  6601   a ; as shown in  FIG. 103(A) , when joined to the mobile telephone lower part  6601   a , operation is disabled, to prevent operation by mistake. 
     The mobile telephone  6601  is normally used in the state shown in  FIG. 103(A) , with the mobile telephone lower part  6601   a  and the mobile telephone upper part  6601   b  joined. At this time, vibration of a piezoelectric bimorph element  2525  and operation of an ordinary microphone  223  are enabled, while a bone conduction microphone  6523  and an ordinary earphone  213  are disabled. The way in which the device is used in this state is shared with other mobile telephone embodiments. 
     It is possible for the mobile telephone  6601  of the seventieth embodiment to be further used with the mobile telephone upper part  6601   b  separated from the mobile telephone lower part  6601   a  as shown in  FIG. 103(B) . At this time, in the mobile telephone upper part  6601   b , vibration of the piezoelectric bimorph element  2525  as well as operation for the bone conduction microphone  6523  and the upper part operating unit  6609 , are enabled. In the mobile telephone lower part  6601   a  as well, the ordinary microphone  22  and the ordinary earphone  213  are enabled. Switching of the aforedescribed bone conduction microphone  6523 , the ordinary earphone  213 , and the upper part operating unit  6609  between the enabled and disabled states takes place automatically, based on a determination as to whether the mobile telephone lower part  6601   a  and the mobile telephone upper part  6601   b  are joined or separated, as discussed below. In this way, in the state shown in  FIG. 103(B) , the mobile telephone lower part  6601   a  functions independently as an ordinary mobile telephone, while the mobile telephone upper part  6601   b  functions as a wireless outgoing-talk/incoming-talk unit for the mobile telephone lower part  6601   a.    
     The way in which the device is used in the state of  FIG. 103(B)  in the aforedescribed manner can be understood according to the sixty-ninth embodiment of  FIG. 101 . Specifically, like the ultra-compact mobile telephone  6501  of the sixty-ninth embodiment, it is possible for the separated mobile telephone upper part  6601   b  to function firstly as an incoming call vibrator; secondly, to make possible cartilage conduction calling while the mobile telephone lower part  6601   a  is kept in a purse or the like for example; and thirdly, to make possible cartilage conduction calling in videoconferencing mode with the mobile telephone lower part  6601   a  held away from the face. During cartilage conduction calling, in the same manner as with the ultra-compact mobile telephone  6501  of the sixty-ninth embodiment, the cartilage conduction unit  6626  is placed in contact with the with the ear cartilage of the tragus or the like, and the bone conduction microphone  6523  is placed against the cheekbone or lower jawbone. 
     As shown in  FIG. 103(B) , the mobile telephone upper part  6601   b  is furnished with a clip  6601   c  for clipping to the mouth of a pocket of clothing or the like. While joined to the mobile telephone lower part  6601   a , this clip  6601   c  is accommodated within a housing recess  6601   d  and is not visible from the outside, as shown in  FIG. 103(A) . The mobile telephone upper part  6601   b  is further furnished with a pair of charging contacts  6648   a  which, in the joined state, contact auxiliary charging contacts  1448   b  provided to the mobile telephone lower part  6601   a . In the joined state shown in  FIG. 103(A) , when the mobile telephone lower part  6601   a  is being charged, the mobile telephone upper part  6601   b  is charged at the same time, via contact between the auxiliary charging contacts  1448   b  and the charging contacts  6648   a . Contact versus non-contact by the auxiliary charging contacts  1448   b  and the charging contacts  6648   a  is a parameter utilized in determining whether the mobile telephone lower part  6601   a  and the mobile telephone upper part  6601   b  are joined or separated as mentioned above, and automatically switches the bone conduction microphone  6523 , the ordinary earphone  213 , and the upper part operating unit  6609  between the enabled and disabled states. 
       FIG. 104  is a block diagram of the seventieth embodiment, in which like portions are assigned the same symbols as in  FIG. 102 .  FIG. 104  has much in common with the block diagram of the sixty-ninth embodiment of  FIG. 102 , and therefore the same reference numerals as those assigned to these parts have been assigned to the corresponding portions. 
     A first point of difference between the mobile telephone upper part  6601   b  of  FIG. 104  and the ultra-compact mobile telephone  6501  of  FIG. 102  resides in a feature whereby a power supply unit  6648  is charged from the charging contacts  1448   a . A second point resides in a feature of providing the upper part operating unit  6609 , which transmits to a controller  6638  a call answer operation during separation in the aforedescribed manner. On the basis of the state of the charging contacts  6648   a , the controller  6638  determines whether a contact state or a non-contact state exists, and in a state in which the contact state is determined to exist, the controller  6639  disables the operating unit  6609 , and does not accept operations therefrom. A third point resides in a feature whereby the mobile telephone upper part  6601   b  is not constituted as an independently functioning telephone function unit, but rather serves as an outgoing-talk/incoming-talk unit  6645  for the mobile telephone upper part  6601   b . A fourth point resides in a feature whereby, in a state like that described above, in which the charging contacts  6648   a  have been determined to be in the contact state, the controller  6639  enables the bone conduction microphone  6523  of the outgoing-talk/incoming-talk unit  6645 . 
     A first point of difference between the mobile telephone lower part  6601   a  of  FIG. 104  and the ordinary mobile telephone  1601  of  FIG. 102  resides a feature whereby, when the power supply unit  1448  is charged by an external charger via the main charging contacts  1448   a , a portion thereof can be supplied to the charging contacts  6648   a  of the mobile telephone upper part  6601   b  via the auxiliary charging contacts  1448   b . A second point resides a feature whereby, when the auxiliary charging contacts  1448   b  are determined to be in the contact state, the controller  239  enables the ordinary earphone  213  of the outgoing-talk/incoming-talk unit  45 . 
     Seventy-First Embodiment 
       FIG. 105  is a perspective view and a cross sectional view of a seventy-first embodiment according to an aspect of the present invention, constituted as a mobile telephone  6701 . The mobile telephone  6701  of the seventy-first embodiment has much in common with the mobile telephone  6601  of the seventieth embodiment in  FIG. 103  and  FIG. 104 , and therefore the same reference numerals are assigned to the common portions, omitting descriptions unless necessary. 
     A main difference between the seventy-first embodiment of  FIG. 105  and the seventieth embodiment is a structure in which the fact that the mobile telephone is separable into an upper part and a lower part is utilized to largely prevent vibration of a cartilage conduction unit furnished in the upper part from being transmitted to the lower part when the two are joined. The following specific description is based on  FIG. 105 . 
     As shown in  FIG. 105(A) , the mobile telephone  6701  of the seventy-first embodiment, like the seventieth embodiment, comprises a mobile telephone lower part  6701   a  and a mobile telephone upper part  6701   b , the two being separable. In the mobile telephone upper part  6701   b , the mobile telephone  6701  upper part is furnished with a hard left-ear cartilage conduction unit  6726  in the left corner of the upper part of the mobile telephone  6701 , and in the interior thereof a piezoelectric bimorph element  2525  is held in cantilever fashion in a lateral/longitudinal direction. Further, the mobile telephone upper part  6701   b  is furnished with a hard right-ear cartilage conduction unit  6724  in the right corner of the upper part of the mobile telephone  6701  upper part. The left-ear cartilage conduction unit  6726  and the right-ear cartilage conduction unit  6724  are integrally linked by a hard linking unit of the same material, so that vibration of the piezoelectric bimorph element  2525  received by the left-ear cartilage conduction unit  6726  is transmitted to the right-ear cartilage conduction unit  6724  as well. In this sense, the seventy-first embodiment has aspects in common with the sixty-fourth to sixty-seventh embodiments in  FIG. 96  to  FIG. 99 . While not depicted in  FIG. 105  in order to avoid complexity, the linking unit for linking the left-ear cartilage conduction unit  6726  and the right-ear cartilage conduction unit  6724  can be one for which the structure of the linking units  6027 ,  6127 ,  6227 , and  6327  in  FIG. 96  to  FIG. 99 , or an analogous structure, is adopted, as appropriate. The mobile telephone upper part  6701   b  of the seventy-first embodiment is not furnished with a bone conduction mic. 
     In the seventy-first embodiment, as shown in  FIG. 105(A) , transmission of vibration of the piezoelectric bimorph element  2525  of the mobile telephone upper part  6701   b  to the mobile telephone lower part  6701   a  is largely prevented by anchoring an elastic body  6765  to the upper end of the mobile telephone lower part  6701   a . The significance of the elastic body  6765  is comparable to that of the elastic bodies  6065 ,  6165 ,  6265 , and  6365  in the sixty-fourth to sixty-seventh embodiments of  FIG. 96  to  FIG. 99 . In the case of the seventy-first embodiment, in view of the fact that the one side of the joined section is made up by the elastic body  6765 , it would be possible to utilize the elasticity thereof to constitute a planar fastener. For example, as shown in fragmentary cross sectional view in  FIG. 105(B) , the joining face on the mobile telephone upper part  6701   b  side may be furnished with a plurality of fungiform protrusions  6701   c , while the surface on the opposing elastic body  6765  side may be furnished with a plurality of small openings  6765   a  at corresponding locations. The diameter of the openings  6765   a  is set to one smaller than the head section of the fungiform protrusions  6701   c , but larger than the root section. By means of such a configuration, the mobile telephone upper part  6701   b  and the elastic body  6765  can be joined through respective fitting of the fungiform protrusions  6701   c  into the openings  6765   a  in opposition to the elasticity of the elastic body  6765 . The planar fastener structure shown in  FIG. 105(B)  can in principle be utilized for anchoring the elastic body  6765  and the mobile telephone lower part  6701   a  as well. In this case, the heads of the fungiform protrusions  6701   c  to be furnished to the upper surface of the mobile telephone lower part  6701   a  would not be smoothly spherical in shape as in in  FIG. 105(B) , but instead, for example, a sharp triangular shape, to provide a so-called “fixed” structure which, once driven into the openings of the elastic body  6765 , will not become dislodged. 
       FIG. 105(C)  shows a state in which the mobile telephone upper part  6701   b  is separated from the mobile telephone lower part  6701   a . From the drawing it is clear that the auxiliary charging contacts  1448   b  are furnished to the surface of the elastic body  6765 . In order to avoid complexity, in  FIG. 105(C) , the fungiform protrusions  6701   c  and the openings  6765   a  shown in  FIG. 105(B)  have been omitted from the illustration. In the seventy-first embodiment, when the mobile telephone upper part  6701   b  has been separated, to listen to a call, either the right-ear cartilage conduction unit  6724  or the left-ear cartilage conduction unit  6726  is placed in contact with the ear cartilage, while to speak, the ordinary microphone  223  of the mobile telephone lower part  6701   a  is used, just as in the joined state of  FIG. 105(A) . For videoconferencing use, the ordinary microphone  223  is used while placed in videoconferencing mode. Neither the right-ear cartilage conduction unit  6724  nor the left-ear cartilage conduction unit  6726  is designed for exclusive use in the right ear or the left ear, and therefore can be placed in contact with any ear cartilage. Moreover, both of the cartilage conduction units could be utilized instead of just one, for use while placed in contact with cartilage at two locations. 
       FIG. 106  is a block diagram of the seventy-first embodiment, in which like portions have been assigned the same symbols as in  FIG. 105 . The block diagram of  FIG. 106  has much in common with the block diagram of the seventieth embodiment in  FIG. 104 , and therefore the same reference numerals as those assigned to these parts have been assigned to the corresponding portions, and descriptions omitted.  FIG. 106  differs from  FIG. 104  in that the outgoing-talk processing unit and the bone conduction microphone are omitted. 
     The various features shown in the embodiments of the present invention are not necessarily unique to the individual embodiments in which they appear, and insofar as it is possible to utilize the advantages thereof, the features of the respective embodiments may be utilized in modified form, or utilized in combination, as appropriate. For example, the bone conduction microphone in the sixty-ninth to seventy-first embodiments may instead be configured as an ordinary microphone for picking up air-conducted sound. In the seventieth embodiment, the bone conduction microphone may be omitted, as in the seventy-first embodiment. Conversely, it would be possible to adopt a bone conduction microphone in the seventy-first embodiment. At this time, it would be preferable to situate the bone conduction microphone in the center of the mobile telephone upper part  6710   b  between the right cartilage conduction unit  6724  and the left cartilage conduction unit  6726 . In this case, because the cartilage conduction units and the bone conduction microphone are close together, a method of use in which the bone conduction microphone is placed against to bone behind the ear, and the cartilage conduction units are placed against the back side of the ear cartilage, as in the twentieth embodiment of  FIG. 33  and the twenty-fourth embodiment of  FIG. 37 , would be possible as well. 
     The cartilage conduction units in the sixty-ninth to seventy-first embodiments are configured using piezoelectric bimorph elements as the cartilage conduction vibration sources, but there is no limitation to this, and electromagnetic vibrators like those shown in other aforedescribed embodiments may be adopted as the cartilage conduction vibration sources. In the seventieth embodiment, the cartilage conduction vibration source is supported at one corner of the mobile telephone upper part, while the bone conduction microphone is situated at the other; however, in a case in which cartilage conduction vibration sources for the right ear and the left ear, respectively, are furnished at both corners of the mobile telephone upper part, it would be preferable to situate the bone conduction microphone in the center of the mobile telephone upper part between the pair of cartilage conduction vibration sources. 
     Further, the means for charging the mobile telephone upper part from the mobile telephone lower part in the seventieth embodiment or seventy-first embodiment is not limited to the electrical contacts shown in these embodiments, and may instead be configured to involve contactless charging through electromagnetic induction, for example. 
     In the seventy-first embodiment, the elastic body  6765  is anchored to the mobile telephone lower part  6701   a  side, with the mobile telephone upper part  6701   b  being detachably attached to the elastic body  6765 ; however, there is no limitation to this particular implementation. For example, in an arrangement opposite that of the seventy-first embodiment, it would be possible to configure the elastic body  6765  to be anchored to the mobile telephone upper part  6701   b  side, with the mobile telephone lower part  6701   a  being detachably attached to the elastic body  6765 . 
     Seventy-Second Embodiment 
       FIG. 107  is a block diagram relating to a seventy-second embodiment according to an aspect of the present invention, configured as a mobile telephone  6801 . Like the fifty-seventh embodiment of  FIG. 87 , in the seventy-second embodiment, the drive circuit for a piezoelectric bimorph element  5325  serving as the cartilage conduction vibration source is configured as a single-chip integrated power management IC  5303 , together with a power management circuit for supplying power to each of the parts of the mobile telephone  6801 . The block diagram of  FIG. 107  has much in common with the block diagram of  FIG. 87 , and therefore the same reference numerals are assigned to like parts, and descriptions are omitted. In the mobile telephone  6801  of the seventy-second embodiment, the cartilage conduction units are not separable as in the seventieth embodiment and the seventy-first embodiment; instead, as in the sixty-fifth embodiment of  FIG. 97  for example, the cartilage conduction units  6124 ,  6126  are anchored to the mobile telephone body, and the piezoelectric bimorph element or other cartilage conduction vibration source  2525  are held thereby. Consequently, during videoconferencing, the cartilage conduction unit is held away from the ear, and instead air-conducted sound is emitted from a videoconferencing speaker  5351 . 
     The seventy-second embodiment of  FIG. 107  and the fifty-seventh embodiment of  FIG. 87  differ in terms of control of the power supply to a charge pump circuit  5354 , and in control associated therewith. Set forth in specific terms, the charge pump circuit  5354  is connected, via a switch circuit  5354   a , to a power management circuit  5353 , the power supply being controlled through on/off switching of the switch circuit  5354   a  by a controller  5321 . Specifically, supply of power to the charge pump circuit  5354  is initiated by turning on the switch circuit  5354   a  in response to an incoming call signal or a call request signal, and is halted by turning off the switch circuit  5354   a  in response to call disconnect operation. In interlocking fashion with switching off of the switch circuit  5354   a , the controller  5321  also halts a pair of phase inversion clocks ( 3 ) which are supplied to the charge pump circuit  5354  by the controller  5321 . 
     During on/off switching of the charge pump circuit  5354 , the voltage becomes unstable in transient fashion, and this causes popping sounds to be generated by the piezoelectric bimorph element  5325 . In order to prevent this, a muting circuit  5340   a  is inserted between an amplifier  5340  and the piezoelectric bimorph element  5325 . Then, under the control of the controller  5321 , the muting circuit  5340   a  is turned on for a predetermined time interval prior to on/off switching of the charge pump circuit  5354 , so that voltage fluctuations of the amp  5340   a  are not transmitted to the piezoelectric bimorph element  5325 . The muting circuit  5340   a  stays on for a somewhat longer time interval than the time interval needed for the charge pump circuit  5354  to stabilize, then unmutes by turning off at a timing at which the voltage can be expected to have stabilized. Through such on/off switching of the muting circuit  5340   a , it is possible to prevent generation of popping sounds during on/off switching of the charge pump circuit  5354 , as well as to drive the piezoelectric bimorph element  5325  once the charge pump circuit  5354  has reached a power supply state with no popping sounds. 
       FIG. 108  is timing charts showing power supply control to the charge pump circuit  5354  in the seventy-second embodiment.  FIG. 108(A)  is a timing chart in a case in which a telephone receives an incoming call; firstly, at timing t 1  at which an incoming call is received in the standby state, the muting circuit  5340   a  switches on. Upon entering a state at timing t 2 , in which the piezoelectric bimorph element  5325  is thereby unaffected by voltage fluctuations of the amp  5340 , the switch circuit  5354   a  switches on, and supply of power from the power management circuit  5353  to the charge pump circuit  5354  is initiated, initiating supply of phase inversion clocks ( 3 ) from the controller  5321  as well. As shown conceptually by diagonal lines in  FIG. 108(A) , from initial startup until reaching a predetermined voltage, the output voltage of the charge pump circuit  5354  is not stable during a transient period. The muting circuit  5340   a  goes on and maintains a muted state during a time slot sufficient to cover this transient period, then unmutes by turning off at a timing t 3  at which the voltage can be expected to have stabilized. In so doing, regardless of when a call answer operation is performed, the piezoelectric bimorph element  5325  will be in a state of readiness that enables cartilage conduction calling. The reason for prompting such an operation at the point in time that an incoming call signal is received is so that the piezoelectric bimorph element  5325  reliably enters the activated state when the call is initiated, as there are conceivably cases in which the call answer operation is performed very rapidly. 
     Next, the call is initiated at arbitrary timing t 4  once a call answer operation is performed. Then, when a call disconnect operation is made at timing t 5 , in response to this, firstly, the muting circuit  5340   a  turns on. Then, upon entering a state at timing t 6 , in which the piezoelectric bimorph element  5325  will not be affected by voltage fluctuations of the amp  5340 , the switch circuit  5354   a  switches off, power supply from the power management circuit  5353  to the charge pump circuit  5354  is interrupted, and supply of phase inversion clocks ( 3 ) from the controller  5321  is halted as well. As shown conceptually by diagonal lines in  FIG. 108(A) , during halting of function of the charge pump circuit  5354 , the output voltage is not stable during a transient period. The muting circuit  5430   a  stays on during a time slot sufficient to cover this transient period, then turns off at a timing t 7  at which stability can be expected to have halted. In so doing, generation of popping sounds from the piezoelectric bimorph element  5325  can be prevented, even when the charge pump circuit  5354  turns off. 
       FIG. 108(B)  is a timing chart in the case of placing a telephone call. At timing t 1 , a contact input operation is initiated by selecting phonebook data or through manual input. At this point in time, as it is not certain whether a call will actually be placed, the power supply to the charge pump circuit  5354  is suspended. At arbitrary timing t 2 , at which the contact input operation is completed and a call request operation is performed, in response to this, firstly, the muting circuit  5340   a  turns on. Then, in the same manner as in  FIG. 108(A) , upon entering a state at timing t 3  in which the piezoelectric bimorph element  5325  will not be affected by voltage fluctuations of the amp  5340 , the switch circuit  5354   a  switches on, and power supply from the power management circuit  5353  to the charge pump circuit  5354  is initiated, initiating supply of phase inversion clocks ( 3 ) from the controller  5321  as well. In the same manner as in  FIG. 108(A) , the muting circuit  5430   a  turns off at timing t 4 , at which the voltage can be expected to have stabilized. The call is then initiated at timing t 5 , by a call answer operation performed by the called party in response to the call request. Due to the sufficient length of time until a call answer operation is performed by the called party in response to the call request, upon entering the startup process of the pump charge circuit  5354  in response to the call request operation, the piezoelectric bimorph element  5325  can reliably be anticipated to be in the activated state in reliable fashion at the time of initiation of the call, as shown in  FIG. 108(B) . Even when the piezoelectric bimorph element  5325  enters the activated state due to a call request operation, the call is not initiated unless the called party performs a call answer operation; however, because it is conceivable that call setup would not take place in time if the piezoelectric bimorph element  5325  does not start up until after the called party performs a call answer operation, the piezoelectric bimorph element  5325  is placed in the activated state without waiting for the call to be set up. 
     Next, when a call disconnection operation is performed at timing t 6 , in response to this, firstly, the muting circuit  5340   a  turns on, in the same manner as in  FIG. 108(A) . Then, upon entering a state at timing t 7 , in which the piezoelectric bimorph element  5325  will not be affected by voltage fluctuations of the amp  5340 , the switch circuit  5354   a  switches off, supply of power from the power management circuit  5353  to the charge pump circuit  5354  is interrupted, and supply of phase inversion clocks ( 3 ) from the controller  5321  is halted as well. In the same manner as in  FIG. 108(A) , the muting circuit  5430   a  stays on during a time slot sufficient to cover the transient period when functioning of the charge pump circuit  5354  halts, then turns off at a timing t 8  at which stability can be expected to have halted. In so doing, in the same manner as in  FIG. 108(A) , generation of popping sounds or the like from the piezoelectric bimorph element  5325  can be prevented, even when the charge pump circuit  5354  turns off. As described above, there may be cases in which the called party fails to perform a call answer operation in response to the call request operation, and at such times a disconnect operation is performed without setting up the call. In this case,  FIG. 108(B)  may be understood to mean that no call state exists from t 5  to t 6  which are depicted between the call request operation at t 2  and the disconnect operation at t 6 . 
       FIG. 109  is a flowchart of operation of an application processor  5339  in the seventy-second embodiment shown in  FIG. 107  and  FIG. 108 . The flow in  FIG. 109  primarily describes the functions of power supply control to the charge pump circuit  5354 , and therefore operations centered on related functions have been extracted for illustration. Consequently, in the seventy-second embodiment, there are other operations of the application processor  5339 , such as typical functions of mobile telephones and like, which are not represented in the flow of  FIG. 109 . The flow of  FIG. 109  starts when the main power source of the mobile telephone  6801  is turned on, and in Step S 302 , initial startup and a function check of each unit are performed, as well as initiating screen display on a display unit  5305 . Next, in Step S 304 , supply of power to the charge pump circuit  5354  turns off, and the routine advances to Step S 306 . Thus, the mobile telephone  6801  of the seventy-second embodiment firstly turns off the supply of power to the charge pump circuit  5354  and starts up. 
     In Step  306 , a check for an incoming call is performed, and in the event there is an incoming call, the routine advances to Step S 308 , and checks whether or not there is a videoconference. In event there is no videoconference, the routine advances to Step S 310 , and the muting circuit  5340   a  is instructed to initiate muting for a predetermined time interval. Next, advancing to Step S 312 , an instruction to turn on the charge pump circuit  5354  is issued, and the routine advances to Step S 314 . To facilitate understanding, Step S 310  and Step S 312  are described as being functions of the application processor  5339 ; however, in actual practice, sequence control to mute for a predetermined time interval and to power on the charge pump circuit  5354  is delegated to the integrated power management IC  5303 . In this case, in Step S 310 , an instruction to turn on the charge pump circuit  5354  is simply issued from the application processor  5339  to the controller  5321 , and the routine advances to Step S 314 . 
     In Step S 314 , a check is made to determine whether or not a call answer operation has been performed, and in the event that no operation is detected, the routine returns to Step S 306 , and repeats Step S 306  to Step S 312  for as long as the incoming call is ongoing. In this case, in the event that the muting for a predetermined time interval and powering on of the charge pump circuit  5354  have been completed, Step S 310  and Step S 312  are omitted. On the other hand, when a call answer operation has been detected in Step S 314 , the routine advances to the call process of Step S 328 . 
     On the other hand, in the case that no incoming call is detected in Step S 306 , the routine advances to Step S 316 . When an incoming videoconference is detected in Step S 308 , the routine advances to Step S 318 , performs videoconferencing processes, and advances to Step S 316 . The videoconferencing processes of Step S 318  correspond to processes lasting from initiation of videoconferencing to calling and disconnection thereof. Consequently, advance from Step S 318  to Step S 316  takes place when the videoconference is disconnected. The videoconferencing processes include a process for emitting the voice of the other caller from an air-conduction speaker during the call. In this way, in cases in which a videoconference is detected, the telephone is used with the piezoelectric bimorph element  5325  held away from the ear cartilage, and therefore from the outset, no power is fed to the charge pump circuit  5354 . 
     In Step S 316 , a check is made to determine whether or not a contact input operation has been performed, and in the event that an input operation has been performed, the routine proceeds to Step S 320 , and checks whether a call request operation has been performed. In the event that a call request operation has been performed, the routine advances to Step S 322 , and checks whether a videoconference request operation has been performed. In the event that there is no videoconference request, the routine advances to Step S 324 , and the muting circuit  5340   a  is instructed to initiate muting for a predetermined time interval. Next, advancing to Step S 326 , an instruction to turn on the charge pump circuit  5354  is issued, and the routine advances to Step S 328 . As in Step S 310  and Step S 312 , sequence control in relation to Step S 324  and Step S 326  is delegated to the controller  5321  of the integrated power management IC  5303 . 
     On the other hand, in the event that contact input is not detected in Step S 316 , or in a case in which no call request operation has been detected in Step S 320 , the routine advances to Step S 336 . When an incoming videoconference is detected in Step S 322 , the routine advances to Step S 338 , performs videoconferencing processes, and advances to Step S 336 . The case of videoconferencing processes of Step S 338  corresponds to the process of awaiting a call answer operation by the called party, and processes based on a call answer operation, lasting from initiation of videoconferencing to calling and disconnection thereof. Consequently, advance from Step S 338  to Step S 336  occurs when the videoconference is disconnected, or when a call request is disconnected in the absence of a call answer operation by the called party. As in Step S 318 , the videoconferencing processes in Step S 338  include emitting the voice of the other caller from an air-conduction speaker during the call, and from the outset, no power is fed to the charge pump circuit  5354 . 
     In Step S 328 , call processes based on a call answer operation in Step S 314  or a call request operation in Step S 320  are performed. In more specific terms, the call processes in Step S 328  refer, in the case of a routine via Step S 314 , to functions taking place during the call, and include management to advance to Step S 330  at each of predetermined time intervals and check whether there has been a disconnect operation. Step S 328  and Step S 330  are repeated in this fashion in the absence of a disconnect operation. On the other hand, in the case of a routine via a call request operation made in Step S 320 , the processes refer to the function of awaiting a call answer operation by called party, and functions taking place during the call after a call answer operation. In this case as well, the routine advances to Step S 330  at each of predetermined time intervals, and checks whether there has been a disconnect operation. At this time, when a disconnect operation has been detected in Step S 330  in the absence of a call answer process by the called party, as a result, only the called party call answer operation wait function will have taken place in Step S 328 . 
     Once a disconnect operation is detected in Step S 330 , the routine advances to Step S 322 , and the muting circuit  5430   a  is instructed to initiate muting for a predetermined time interval. Next, the routine advances to Step S 334 , the charge pump circuit  5354  is instructed to turn off, and the routine advances to Step S 336 . As in Step S 310  and Step S 312 , sequence control in relation to Step S 332  and Step S 334  is delegated to the controller  5321  of the integrated power management IC  5303 . 
     In Step S 336 , a check is performed to determine whether or not the main power source has been turned off, and in the event the power is not detected to be off, the routine returns to Step S 306 , and thereafter repeats the aforedescribed series of flows until detected that the main power source has been turned off. Once detected that the main power source has been turned off, the flow terminates. 
     The various features shown in the embodiments of the present invention are not necessarily unique to the individual embodiments in which they appear, and insofar as it is possible to utilize the advantages thereof, the features of the respective embodiments may be utilized in modified form, or utilized in combination, as appropriate. For example, in the seventy-second embodiment, a charge pump circuit is adopted as the voltage booster circuit for driving the piezoelectric bimorph elements, and while this is a suitable selection, there is no limitation to this, and employment of other voltage booster circuit, as appropriate, is not precluded. 
     Seventy-Third Embodiment 
       FIG. 110  is a perspective view relating to a seventy-third embodiment according to an aspect of the present invention, configured as a mobile telephone  6901 . In terms of external appearance, the seventy-third embodiment has much in common with the fifty-fifth embodiment shown in  FIG. 83 , and in terms of internal configuration and function has much in common with the fourth embodiment shown in  FIG. 8  and  FIG. 10 ; therefore, the common portions are assigned the same reference numerals as in these embodiments, and discussions are omitted. 
     A point of difference between the seventy-third embodiment of  FIG. 110  and the fourth embodiment of  FIG. 55  is that, as shown in perspective view from the front in  FIG. 110(A) , the videoconferencing in-camera  6917  is situated in proximity to the lower right corner of the mobile telephone  6901 . In the seventy-third embodiment, there is no extra available space in the upper part of the mobile telephone  6901 , due to the placement of cartilage conduction units  5124  and  5126  and internal cartilage conduction vibration sources for transmitting vibration thereto. Therefore, in the seventy-third embodiment, the videoconferencing in-camera  6917  is situated in proximity to the lower right corner of the mobile telephone  6901 , on the opposite side from the cartilage conduction units  5124  and  5126 , with a display screen  6905  therebetween. 
     The seventy-third embodiment is furnished with a display lamp  6965  comprising an LED or the like, for notifying of incoming calls or emails, and the videoconferencing in-camera  6917  is situated in proximity to this display lamp  6965 . By prompting the display lamp  6965  to blink randomly during videoconferencing, the user&#39;s line of sight can be directed towards the videoconferencing in-camera  6917 . In so doing, the line of sight of the user&#39;s face displayed on the display unit of the other caller&#39;s video phone will be oriented squarely frontward. This feature will be further discussed below.  FIG. 110(B)  is a rear perspective view of the mobile telephone  6901 , and shows the placement of a rear main camera  6955 . 
     As shown in  FIG. 110(C) , the mobile telephone  6901  of the seventy-third embodiment is used while held in landscape orientation with the long edges of the display screen  6905  oriented on the horizontal. Because the videoconferencing in-camera  6917  is situated in proximity to the lower right corner of the mobile telephone  6901  as seen in  FIG. 110(A) , when held in landscape orientation as shown in  FIG. 110(C) , the camera is at the upper right corner. In so doing, the videoconferencing in-camera  6917  is able to capture the user&#39;s face at a natural angle from the upper right during a videoconference. Additionally, the videoconferencing in-camera  6917  is situated such that a direction perpendicular to the long edges of the display screen  6905  is aligned with a vertical direction of a captured image as shown in  FIG. 110(C) . In cases in which the other caller&#39;s video phone is held in landscape orientation as well, the other caller&#39;s face will be displayed on the display screen  6905 . The user&#39;s own face is also displayed as shown in  FIG. 110(C) , on the display screen of the other caller&#39;s mobile telephone which is being held in landscape orientation. With regard to portrait orientation versus landscape orientation, the orientation in which the mobile telephone is held can be detected through detection of gravitational acceleration by an ordinary acceleration sensor  49 , and the orientation of an image rotated automatically by 90°; due to the seventy-third embodiment being configured in this fashion, in videoconferencing mode, the image rotation function of the acceleration sensor  49  is halted. When the other caller&#39;s mobile telephone is not being held in landscape orientation, the left and right sides of the user&#39;s own face are cropped at left and right to produce a vertically elongated image, which is displayed on the display unit of the other caller&#39;s mobile telephone. Moreover, when the other caller&#39;s mobile telephone is not being held in landscape orientation, the long edge direction of the display screen becomes the vertical direction of the image, and therefore if nothing were done, the other caller&#39;s face would be displayed in landscape orientation. Consequently, as discussed below, an image from a mobile telephone not held in landscape orientation will be automatically rotated by 90°, for display on the display screen  6905 . At this time, the other caller&#39;s face will be displayed at the center of the vertically elongated image, and therefore there is empty space in which nothing is displayed at the left and right of the display screen  6905 . This empty space can be utilized for display of data. The user&#39;s own voice is captured by a microphone  6923  of the video phone, while the other caller&#39;s voice is output from a speaker  6951 . 
     At this time, the display lamp  6965  is made to blinked randomly in the manner discussed above (for example, flashed randomly in several sets per minute, blinking on and off several times per set, for about 0.5 second each time). An ordinary videoconference is made while looking at the other caller&#39;s face on the display screen  6905 , but this means that the line of sight is not facing towards the videoconferencing in-camera  6917 . Consequently, on the other caller&#39;s screen as well, the line of sight will not be looking towards the other caller. In contrast to this, when the user&#39;s line of sight, attracted by random flickering in the aforedescribed manner, is drawn to the display lamp  6965 , his or her line of sight becomes directed towards the videoconferencing in-camera  6917  which is situated nearby, thus producing the effect that his or her line of sight is facing the other caller, on the other caller&#39;s screen. 
       FIG. 110(D)  shows a state in which the display screen  6905  is split, with the other caller&#39;s face being displayed in a right side screen  6905   a , and an image captured by the rear main camera  6955  being monitor-displayed in a left side screen  6905   b . The monitor-displayed image is transmitted to the other caller, together with the user&#39;s own face captured by the videoconferencing in-camera  6917 . In so doing, a videoconference conversation can take place while sending the other caller an image of the user&#39;s own face, together with scenery or the like currently viewed by the user. 
       FIG. 111  is perspective views showing various videoconferencing modes in the seventy-third embodiment in the aforedescribed manner.  FIG. 111(A)  is the same as  FIG. 110(D) , and shows a mode in which the other caller&#39;s face is displayed in the right side screen  6905   a , while an image captured by the rear main camera  6955  monitor-displayed in the left side screen  6905   b.    
     In contrast to this,  FIG. 111(B)  shows a mode in which the other caller&#39;s face is displayed in the right side screen  6905   a , while an image transmitted by the other caller is displayed in the left side screen  6905   b . Switching between the modes of  FIG. 111(A)  and  FIG. 111(B)  is accomplished by operation of the mobile telephones in mutual agreement with the other caller during the call. It is possible for sent and received images to be still images, not just video images. When sent or received images contain large amounts of data, during intervals that images from the rear main camera  6955  are sent and received, sending and receiving of images takes place on a time-division basis, stopping transmission of face image data to one another. 
     As will be discussed below, during transmission of a user&#39;s own face, together with scenery or the like currently viewed by the user, picture quality drops, but is it possible for images from the rear main camera  6955  and image from the videoconferencing in-camera  6917  to transmitted in synthesized form. In this case, an image containing a user&#39;s own face and scenery or the like currently viewed by the user can be transmitted to a mobile telephone that is not compatible with transmission/reception of images on two screens. 
       FIG. 111(C)  shows a state in which an image of scenery or the like transmitted by the other caller is displayed on the right side screen  6905   a , and an image from the rear main camera  6955  to be sent to the other caller is monitor-displayed on the left side screen  6905   b . In this case, landscapes or the like viewed by the callers can be exchanged with one another during a videoconference. 
       FIG. 112  is a flowchart showing videoconferencing processing in the seventy-third embodiment, and can be understood to describe the details of videoconferencing processing in Step S 36  of the fourth embodiment shown in  FIG. 10 . When videoconferencing processing starts, in Step S 342 , an advisory to the effect that the mobile telephone  6905  should be used while held in landscape orientation is displayed on the display screen  6905 . This display continues for a short while, and in parallel therewith, the flow proceeds directly to Step S 346 , and the speaker  6901  is turned on. Then, in Step S 348 , an advisory announcement to the effect that the mobile telephone  6905  should be used held in landscape orientation is made. In parallel with initiating the announcement, the flow proceeds directly to Step S 349 , and the function of auto-rotation of the image according to the orientation of the mobile telephone  6901  detected by the acceleration sensor  49  is halted. Next, proceeding to Step S 350 , a check is performed to determine whether the other caller&#39;s mobile telephone is landscape position-compatible. In the event that it is not landscape orientation-compatible, the flow proceeds to Step S 352 , in which the received image display is rotated by 90° so that the other caller&#39;s face appears upright in landscape orientation, then advances to Step S 354 . If the phone is one that is landscape orientation-compatible, the flow advances directly to Step S 354 . 
     In Step S 354 , the videoconferencing in-camera  6917  is turned on, and in Step S 356 , the microphone  6923  is turned on. Then, in Step S 358 , a check is performed to determine whether or not the device is in a “dual camera mode” in which both the videoconferencing in-camera  6917  and the rear main camera  6955  are used. The mode can be set manually beforehand, or changed in the course of a videoconference. In the event that the device is not in the “dual camera mode,” in Step S 360 , the rear main camera  6955  is turned off; when already off, nothing is done in this step. Next, the display screen  6905  is set to full-screen display, and image transmission/reception processing is performed in Step S 364 . This processing is the same as that for an ordinary video phone, with processing being performed in time units of procedures. 
     Once the processing of Step S 364  is finished, the routine proceeds to Step S 368 , and checks whether or not a time interval has arrived to randomly flash the display lamp  6965  on the basis of a simple random number process or the like. Upon arriving at a flash time, in Step S 370 , an instruction prompting a single set of flashes by the LED is issued in order to catch the user&#39;s attention to direct his or her line of sight towards the videoconferencing in-camera  6917 , and the routine advances to Step S 372 . When the routine has not yet arrived at a flash time, it proceeds directly to Step S 372 . On the other hand, when detected in Step S 358  that the device is in the “dual camera mode,” the routine proceeds to Step S 374  in which the rear main camera  6955  is turned on, then proceeds to the “dual camera mode” processing of Step S 376 , and when this process finishes, advances to Step S 372 . The details of the “dual camera mode” processing of Step S 376  will be discussed below. In Step S 372 , it is checked whether a videoconference disconnect operation has been performed, and in the event that no such operation has been performed, the routine returns to Step S 358 . Step S 358  to Step S 376  are repeated subsequently until a disconnect operation is performed. Mode changes can be accommodated during this repetition as well. On the other hand, in the event that a disconnect operation is detected in Step S 372 , the flow terminates, and the routine advances to Step S 38  of  FIG. 10 . 
       FIG. 113  shows the details of “dual camera mode” processing in Step S 376  of  FIG. 112 . When the flow starts, in Step S 382 , a check is performed to determine if the device is in a synthesized video mode, and when this is the case, proceeds to Step S 384 , in which the images from the videoconferencing in-camera  6917  and the rear main camera  6955  are synthesized, and an instruction to transmit synthesized video is issued in Step S 386 . Further, in Step S 388 , a full-screen display instruction is issued, in Step S 390  an instruction to display the received synthesized video is issued, and the routine advances to Step S 404 . On the other hand, in the event that the synthesized video mode has not been detected in Step S 382 , the routine advances to Step S 392 . 
     In Step S 392 , a dual screen display instruction is issued, and in Step S 394  an instruction to transmit images from the videoconferencing in-camera  6917  is issued. Further, in Step S 396 , an instruction is issued to display a received image of the other caller&#39;s face on the right side display screen  6905   a , whereupon the routine advances to Step S 398 . In Step S 398 , it is checked whether the mode is one of transmitting images from the rear main camera  6955 , and when this is the case, in Step S 400 , an instruction is issued to monitor-display images from the rear main camera  6955  on the left side display screen  6905   b , as well as to transmit the images to the other caller&#39;s mobile telephone. The routine then advances to Step S 404 . 
     On the other hand, in the case of a confirmation in Step S 398  that the device is not in a mode of transmitting images from the rear main camera  6955 , this means that the mode is one of receiving images from the other caller, and therefore the routine proceeds to Step S 402 , whereupon an instruction to display images received from the other caller&#39;s rear main camera on the left side display screen  6905   b  is issued, and the routine proceeds to Step S 404 . In Step S 404 , a check is performed to determine whether or not a time interval to randomly flash the display lamp  6965  has arrived, and upon arriving at such a flash time, in Step S 406 , an instruction to attract attention by blinking the display lamp  6965  is issued, and the routine advances to Step S 408 . When the routine has not yet arrived at a flash time, it proceeds directly to Step S 408 . The purpose is the same as in Step S 368  and Step S 370  in  FIG. 112 . 
     In Step S 408 , a check is performed to determine if a “dual camera mode” videoconference termination change has been made, and in the event that no such operation has been performed, the routine returns to Step S 382 . Step S 382  to Step S 408  are repeated subsequently until a termination operation is performed. Mode changes can be accommodated during this repetition as well. On the other hand, in the event that a termination operation is detected in Step S 408 , the flow terminates, and the routine advances to Step S 372  of  FIG. 112 . 
     Implementation of the present invention is not limited to the aforedescribed embodiments, and the various advantages of the present invention can be enjoyed in other embodiments as well. Further, these features may be interchanged or utilized in combination among various embodiments. For example, the flowcharts shown in  FIG. 112  and  FIG. 113  can be adopted in the videoconferencing processing of Step S 318  and Step S 338  of the seventy-second embodiment shown in  FIG. 109  as well. 
     Whereas conventional videoconferencing in-cameras are arranged such that a direction parallel to the long edges of the rectangular display screen  6905  coincides with a vertical direction of image capture, the videoconferencing in-camera  6917  in the aforedescribed seventy-third embodiment is arranged such that a direction perpendicular to the long edges of the rectangular display screen  6905  coincides with the vertical direction of image capture, as shown in  FIG. 110(C) . In order avoid confusion in relation to displayed image rotation stemming from this situation, in the seventy-third embodiment, once videoconferencing has been established, the displayed image auto-rotate function based on the acceleration sensor  49  performed in Step S 349  of  FIG. 112  is halted. Then, during a videoconference with another caller, an ordinary mobile telephone rotates the displayed image by 90° by performing Step S 350  and Step S 352 . However, countermeasures for preventing confusion stemming from the arrangement whereby a direction perpendicular to the long edges of the rectangular display screen  6905  coincides with the vertical direction of image capture in the videoconferencing in-camera  6917  are not limited to this. For example, a configuration whereby, utilizing the display image auto-rotate function based on the acceleration sensor  49 , the orientation of the displayed image by the auto-rotate function is corrected by 90°, on the basis of whether or not information indicating that the vertical direction of the videoconferencing in-camera  6917  diverges by 90° from normal is available, would also be acceptable. Further, a configuration whereby, in the same manner as a conventional device, the videoconferencing in-camera  6917  is arranged such that the direction parallel to the long edges of the rectangular display screen  6905  coincides with the vertical direction of image capture, and during videoconferencing, the display image is always rotated 90° by the auto-rotate function, would also be acceptable. 
     Additionally, in cases in which the vibration source of the cartilage conduction unit  5124  in the seventy-third embodiment is configured as a piezoelectric bimorph element, it is possible for the element to also function as an impact sensor in the manner described in the fourth embodiment, and therefore a configuration whereby switching between main camera image transmission mode and reception mode during a videoconference is performed by detecting the impact produced by lightly tapping the cartilage conduction unit  5124  with the index finger, with the mobile telephone  6901  held sideways. Further, in the thirteenth embodiment and the seventeenth embodiment, the cartilage conduction unit functions as an incoming call vibrator, and it is possible for the cartilage conduction unit  5124  or  5126  of the seventy-third embodiment to likewise be concomitantly employed as a vibrating unit for notification purposes. For example, the cartilage conduction unit  5124  or  5126  could be configured to produce predetermined vibration every minute, thereby transmitting passage of time during a videoconference, to a hand holding the mobile telephone  6901  sideways. 
     Seventy-Fourth Embodiment 
       FIG. 114  is a block diagram relating to a seventy-fourth embodiment according to an aspect of the present invention, configured as a cartilage conduction vibration source device for a mobile telephone. The seventy-fourth embodiment has, as its foundation, considerations based on the structure of the ear and on actual measurement data for the mobile telephone reviewed in  FIG. 79  and  FIG. 80 , as well as a review of the frequency characteristic correction unit (the cartilage conduction equalizer  5038  and the cartilage conduction low-pass filter  5040 ) in the fifty-fourth embodiment of  FIG. 82  configured on the basis thereof. Configuration-wise, it relates to functions corresponding to the analog front end unit  5336  of the integrated power management IC  5303 , the cartilage conduction acoustic signal processing unit  5338 , the charge pump circuit  5354 , and the amp  5340  in the fifty-seventh embodiment of  FIG. 87  and the seventy-second embodiment of  FIG. 107 . Consequently, the details of the significance of this configuration may be understood through reference to the disclosures, and description is omitted where redundant. 
     The seventy-fourth embodiment of  FIG. 114  provides a cartilage conduction vibration source device controllable by an application processor  7039  and a power management circuit  7053  in an ordinary mobile telephone, and specifically is configured as a piezoelectric bimorph element  7013  (illustrated as an equivalent circuit, together with a capacitor) as the cartilage conduction vibration source, and a driver circuit  7003  therefor. The driver circuit is basically a drive amp for the piezoelectric bimorph element  7013 , and incorporates therein an analog acoustic processing circuit  7038  serving as the frequency characteristic correction unit. Driving at suitable frequency characteristics, with the piezoelectric bimorph element  7013  as the cartilage conduction vibration source, is possible simply by connecting an audio output from the ordinary application processor  7039 . 
     Stated in more specific terms, an analog sound signal output by a differential from a speaker analog output unit  7039   a  of the application processor  7039  is input to an analog input amp  7036 , and is output through the analog acoustic processing circuit  7038  to analog output amps  7040   a  and  7040   b , then used for differential driving of the piezoelectric bimorph element  7013 . The driver circuit  7003  incorporates a voltage booster circuit  7054  (in specific terms, one comprising a charge pump circuit) for the analog output amps  7040   a  and  7040   b , whereby driving is possible by inputting, as a power source voltage from a power input unit  7054   a , an output voltage (2.7-5.5 V) of the ordinary power management circuit  7053 . 
     The analog acoustic processing circuit  7038  has functions comparable to the cartilage conduction equalizer  5038  and the cartilage conduction low-pass filter  5040  in the fifty-fourth embodiment of  FIG. 82 , and also functions as a startup sequence circuit for automatically reducing clicking noises and popping noises. In some cases, correction of frequency characteristics by the cartilage conduction equalizer  5038  and the cartilage conduction low-pass filter  5040  may be established across the board, while in other cases, custom settings or adjustments are possible according to factors such as the age of the ear. 
     Seventy-Fifth Embodiment 
       FIG. 115  is a block diagram relating to a seventy-fifth embodiment according to an aspect of the present invention. The seventy-fifth embodiment, like the seventy-fourth embodiment, is configured as a cartilage conduction vibration source device for a mobile telephone, and has much in common therewith; therefore, the same reference numerals are assigned to comparable configurations, omitting descriptions thereof. Whereas the seventy-fourth embodiment of  FIG. 114  is configured as an all-analog circuit, the seventy-fifth embodiment of  FIG. 115  differs therefrom in that a digital acoustic processing circuit  7138  is adopted in the driver circuit  7103 . 
     However, as in the seventy-fourth embodiment, the input and output of the driver circuit  7103  are analog, and input analog signal is converted to a digital signal by a DA conversion circuit  7138   a  and input to the digital acoustic processing circuit  7138 , while a digital output of the digital acoustic processing circuit  7138  is converted to an analog signal by a DA conversion circuit  7138   b , and transferred to the analog output amps  7040   a  and  7040   b . The input to the driver circuit  7103  is not a differential input; instead, an analog sound signal from an analog output  7039   b  of the application processor  7039  is input. The issue of whether input takes place by differential signaling or not is not a respective characterizing feature of the seventy-fourth and seventy-fifth embodiments, and therefore an appropriate configuration may be selected, according to the circumstances of connection to the application processor  7039 . 
     Seventh-Sixth Embodiment 
       FIG. 116  is a block diagram relating to a seventy-sixth embodiment according to an aspect of the present invention. The seventy-sixth embodiment, like the seventy-fourth and seventy-fifth embodiments, is configured as a cartilage conduction vibration source device for a mobile telephone, and has much in common therewith; therefore, the same reference numerals are assigned to comparable configurations, omitting descriptions thereof. A point of difference between the seventy-sixth embodiment of  FIG. 116  and the seventy-fourth or seventy-fifth embodiment is that a digital sound signal from a digital output unit ( 12 S)  7039   c  of the application processor  7039  is input to a driver circuit  7203 . Then, in the same manner as in the seventy-fifth embodiment, a digital sound signal from the application processor  7038  is directly input to the digital acoustic processing circuit  7138  by an input unit  7236 . 
     Digital output from the digital acoustic processing circuit  7138  is converted by a DA conversion circuit  7138   c  to an analog signal, which is transferred to an output amp  7240   a , as well as being inverted by an analog output amp  7240   b , and employed for differential driving of the piezoelectric bimorph element  7013 . The issue of whether the analog output of the DA conversion circuit  7138   c  is inverted by the analog output amp  7240   b  as in the seventy-sixth embodiment, or whether two analog signals inverted by the DA conversion circuit  7138   b  itself are output as in the seventy-fifth embodiment, is not a respective characterizing feature of the seventy-fifth and seventy-sixth embodiments, and any appropriate configuration may be selected. 
     Seventy-Seventh Embodiment 
       FIG. 117  is a block diagram relating to a seventy-seventh embodiment according to an aspect of the present invention. The seventy-seventh embodiment, like the seventy-fourth to seventy-sixth embodiments, is configured as a cartilage conduction vibration source device for a mobile telephone, and has much in common therewith; therefore, the same reference numerals are assigned to comparable configurations, omitting descriptions thereof. A point of difference between the seventy-seventh embodiment of  FIG. 117  and the seventy-fourth to seventy-sixth embodiments is that a driver circuit  7303  has an all-digital configuration. Consequently, a digital sound signal output from the digital output unit ( 12 S)  7039   c  of the application processor  7039  is input directly to the digital acoustic processing circuit  7138  by the input unit  7236 , and digital output from the digital acoustic processing circuit  7138  is transferred to class-D power amps  7340   a  and  7340   b.    
     A vibration source module  7313  is provided in combination with a driver circuit  7303  for outputting a digital drive signal as in the seventy-seventh embodiment, and is configured as a piezoelectric bimorph element module incorporating a low-pass filter (in specific terms, a choke coil for smoothing PWM signals)  7313   a  for differential PWM signals output from the class-D power amps  7340   a  and  7340   b . In so doing, even in cases in which the all-digital driver circuit  7303  has been adopted, by providing this in combination with the vibration source module  7313 , there can be provided a cartilage conduction vibration source device controllable by the application processor  7039  and the power management circuit  7053  in an ordinary mobile telephone, without the burden of having to provide an external smoothing choke coil with matched characteristics, or the like. 
     In the forty-fourth embodiment of  FIG. 67 , there is shown a structure in which the piezoelectric bimorph element and the circuit form a resin package which is held as an integrated vibration unit, and the choke coil  7313   a  of the seventy-seventh embodiment of  FIG. 117  can be thought of as the most simple example of a circuit that is integrated with a piezoelectric bimorph element into a resin package, as in the forty-fourth embodiment. Consequently, the shape and holding structure reviewed in the forty-fourth embodiment of  FIG. 67  could be adopted for the vibration source module  7313  of the seventy-seventh embodiment. 
     In the above manner, the seventy-fourth to seventy-seventh embodiments can provide a cartilage conduction vibration source device controllable by the application processor  7039  and the power management circuit  7053  in an ordinary mobile telephone, without the burden of adjustment and review to achieve good cartilage conduction, even in the absence of any knowledge or information about cartilage conduction. The specific configuration is not limited to those of the seventy-fourth to seventy-seventh embodiments, and provided that the advantages thereof can be enjoyed, it is possible to make appropriate changes to the combination of circuit components. The present invention does not just feature configuration as a single driver circuit as in the seventy-fourth to seventy-seventh embodiments, and configurations involving incorporation as part of a large-scale circuit, such as the integrated power management IC  5303  in the fifty-seventh embodiment of  FIG. 87  or the seventy-second embodiment of  FIG. 107 , are also acceptable. 
     Seventy-Eighth Embodiment 
       FIG. 118  is a cross sectional view relating to a seventy-eighth embodiment according to an aspect of the present invention, and is configured as a mobile telephone  7401 .  FIG. 118(A)  is a front cross sectional view of the mobile telephone  7401 , and  FIG. 118(B)  is a side cross sectional view of the mobile telephone  7401  taken in the B 2 -B 2  cross section of  FIG. 118(A) . As shown in  FIG. 118(A) , the configuration of cartilage conduction units  7424 ,  7426  and a linking unit  7427  in the seventy-eighth embodiment, as well as the structure by which the cartilage conduction unit  7424  holds in cantilever fashion a piezoelectric bimorph element  2525  as a cartilage conduction vibration source for transmitting vibration to the cartilage conduction unit  7424 , are shared inter alia with the structure of the sixty-fifth embodiment shown in  FIG. 97(B) . Consequently, to avoid redundancy, descriptions of the significance of these structures are omitted. Like the sixty-first embodiment of  FIG. 91 , a feature of the seventy-eighth embodiment of  FIG. 118  is that the internal weight of the mobile telephone  7410  is utilized in order to suppress a modicum of sound leakage due to transfer of vibration of the cartilage conduction vibration source  2525  to the chassis of the mobile telephone  7401 . The details of the other internal configuration of the mobile telephone  7401  are shared with the embodiments described up to this point (for example, the fifty-fourth embodiment of  FIG. 82 , the seventy-second embodiment of  FIG. 107 , and the like), and therefore in  FIG. 118 , illustrations of these have been omitted to avoid complexity. 
     A sound leakage suppression structure employed in the seventy-eighth embodiment of  FIG. 118  is described below. In the same fashion as in the sixty-fifth embodiment of  FIG. 97 , cartilage conduction units  7424 ,  7426  and a linking unit  7427  are integrally molded from a hard material. This hard material is a material of different acoustic impedance than the chassis of the mobile telephone  7401 . An elastic body  7465  is interposed, as a vibration isolating material, between the chassis of the mobile telephone  7401  and the integrally molded structure of the cartilage conduction units  7424 ,  7426  and the linking unit  7427 , and connects the two such that there is not direct contact between them. This structure provides acoustic blocking between the chassis of the mobile telephone  7401 , and the integrally molded structure of the cartilage conduction units  7424 ,  7426  and the linking unit  7427 . The preceding structure is shared with embodiments described previously, but as it constitutes the base of the sound leakage suppression structure in the seventy-eighth embodiment, the significance thereof has been summed up once again. 
     A cell  7448  is held at top and bottom by hard cell holders (an upper holder  7406  and a lower holder  7416 ). In a center part of the cell  7448 , containment by the rigid holders is avoided, so as to permit swelling associated with the passage of time during use. The upper holder  7406  is furnished with a plurality of pins  7408  for connection to the front surface and rear surface of the mobile telephone  7401 , in sections of small cross-sectional area. Meanwhile, the lower holder  7416 , which is situated at a location away from the plurality of pins  7408 , is furnished with a plurality of elastic bodies  7467  which hold it in a vibration-isolated state, to the front surface and rear surface of the mobile telephone  7401 . 
     In so doing, as shown in  FIG. 118(B) , the cell  7448  installed in the cell holders (the upper holder  7406  and the lower holder  7416 ) is placed within a front side chassis  7401   a  (GUI display part  7405  side), and when covered up with a rear side chassis  7401   b , the plurality of pins  7408  are respectively sandwiched between the front side chassis  7401   a  and the rear side chassis  7401   b  and become pressed into contact thereagainst, whereby the load of the cell  7448  is connected, via the upper holder  7406 , to the chassis of mobile telephone  7401 , in proximity to the cartilage conduction unit  7424 . The significance of the small-cross-sectional area connections afforded by the pins  7408  is that the load connection locations are specifically concentrated in proximity to the cartilage conduction unit  7424  in the chassis of the mobile telephone  7401 . This load connection serves to suppress vibration of the chassis of the mobile telephone  7401  in proximity to the cartilage conduction unit  7424 , which corresponds to the entrance section for vibration transmission. The effect of this is comparable, for example, to that of a damper attached to the bridge of a stringed instrument corresponding to the entrance section for vibration of the strings, and serves to suppress resonance of the entire chassis of the mobile telephone  7401 . 
     Because the cartilage conduction unit  7424  is constituted by a material of different acoustic impedance than the chassis of the mobile telephone  7401 , and is vibration-isolated with respect to the chassis of the mobile telephone  7401  by the elastic body  7465 , a high degree of freedom of vibration is ensured, the effect of vibration suppression due to load connection of the cell  7448  are minimal, and satisfactory cartilage conduction can be obtained. 
     Meanwhile, the plurality of elastic bodies  7467  furnished to the lower holder  7416  are likewise sandwiched between the front side chassis  7401   a  and the rear side chassis  7401   b  and become pressed into contact thereagainst, in which state, due to the elasticity thereof, the lower holder  7416  has a high degree of freedom with respect to the chassis of the mobile telephone  7401 , and the load connection is weak. Consequently, despite fact that the lower holder  7416  is held by the plurality of elastic bodies  7467  in a section situated away from the plurality of pins  7408 , specific concentration of the load connection locations provided by the plurality of pins  7408  is not diminished. 
     Seventy-Ninth Embodiment 
       FIG. 119  is a cross sectional view relating to a seventy-ninth embodiment according to an aspect of the present invention, configured as a mobile telephone  7501 . The seventy-ninth embodiment has much in common with the seventy-eighth embodiment in  FIG. 118 , and therefore the same reference numerals are assigned to common portions, and descriptions thereof are omitted. 
     A point of difference between the seventy-ninth embodiment and the seventy-eighth embodiment lies is that the lower holder  7416  is also furnished with a plurality of pins  7408 , in place of the plurality of elastic bodies  7467 . In so doing, when sandwiched by the front side chassis  7401   a  and the rear side chassis  7401   b , the lower holder  7416  is also provided with a small cross-sectional area connection by the pins  7408 . In the case of the seventy-ninth embodiment, the load connection locations of the cell are dispersed, but as the vibration suppressing effect is dependent upon the distance between the load connection locations and the cartilage conduction unit  7424 , the load connection afforded by the plurality of pins  7408  of the upper holder  7406  remains effective. Consequently, in cases in which priority is given to using common parts for the structures of both the upper holder  7406  and the lower holder  7416  in order to reduce the number of parts, even at the expense of some vibration suppressing effect, it is possible to adopt the configuration of the seventy-ninth embodiment. 
     Eightieth Embodiment 
       FIG. 120  is a cross sectional view relating to an eightieth embodiment according to an aspect of the present invention, configured as a mobile telephone  7601 . The eightieth embodiment has much in common with the seventy-eighth embodiment in  FIG. 118 , and therefore the same reference numerals are assigned to common portions, and descriptions thereof are omitted. 
     A point of difference between the eightieth embodiment and the seventy-eighth embodiment lies is that the elastic body  7465  between the chassis of the mobile telephone  7401  and the integrally molded structure of the cartilage conduction units  7424 ,  7426  and the linking unit  7427  has been omitted. In cases in which sufficient vibration isolating effect can be obtained simply from the difference in acoustic impedance between the aforedescribed integrally molded structure and the chassis, the vibration suppression of the chassis by load connection of the cell  7448  does not appreciably extend to the integrally molded structure, and satisfactory cartilage conduction can be ensured. Consequently, in cases in which priority is given to reducing the number of parts, even at the expense of some cartilage conduction efficiency, to simplify the connection structure of the integrally molded structure and the chassis, it is possible to adopt the configuration of the eightieth embodiment. 
     Eighty-First Embodiment 
       FIG. 121  is a side sectional view relating to the eighty-first embodiment and a modification thereof according to an aspect of the present invention. The eighty-first embodiment and a modification thereof have much in common with the seventy-eighth embodiment in  FIG. 118 . 
     A point of difference between the eighty-first embodiment and the modification thereof and the seventy-eighth embodiment is that the weight used for suppressing sound leakage is used as an internal frame structure of the mobile telephone. The internal frame structure  7748   a  constitutes the majority of the weight of the mobile telephone and is therefore suitable for suppressing sound leakage. 
       FIG. 121(A)  is a side sectional view relating to an eighty-first embodiment, and is configured as a mobile telephone  7701   a . The eighty-first embodiment has much in common with the seventy-eighth embodiment in  FIG. 118  as described above, and therefore the same reference numerals are assigned to common portions, and descriptions thereof are omitted. 
     In the eighty-first embodiment (A), the weight used for suppressing sound leakage as described above has the internal frame structure  7748   a  of the mobile telephone  7701   a . The internal frame structure  7748   a  holds the cell  7448 , holds the circuits and other internal structures, and constitutes the majority of the weight of the mobile telephone. The internal frame structure  7748   a  is connected, via the elastic body  7465 , to the integrally molded structure of the cartilage conduction units  7424 ,  7426  and the linking unit  7427 , and constitutes the principal skeletal structure of a mobile telephone  7701   b . For this reason, the internal frame structure  7748   a , by virtue of the weight thereof, suppresses vibration of the chassis constituting the surface of the mobile telephone  7701   a  in the vicinity of the cartilage conduction unit  7424  in the same manner as the seventy-eighth embodiment of  FIG. 118 . 
       FIG. 121(B)  is a side sectional view relating to the eighty-first embodiment according to an aspect of the present invention, configured as a mobile telephone  7701   b . The first modification example of  FIG. 121(B)  has much in common with the eighty-first embodiment in  FIG. 121(A) , and therefore the same reference numerals are assigned to common portions, and descriptions thereof are omitted. 
     In the first modification example of  FIG. 121(B) , as in the eighty-first embodiment of  FIG. 121(A) , an internal frame structure  7748   b  is connected, via the elastic body  7465 , to the integrally molded structure of the cartilage conduction units  7424 ,  7426  and the linking unit  7427 . However, the chassis of the mobile telephone  7701   b  in the first modification example simply functions as an exterior component covering the perimeter of the mobile telephone  7701   b , and is not directly connected to the integrally molded structure of the cartilage conduction units  7424 ,  7426  and the linking unit  7427 , but is instead held by the internal frame structure  7748   b  via an elastic body  7765  which constitutes the vibration isolating material. For this reason, portions of the internal frame structure  7784   b  in proximity to the cartilage conduction unit  7424  intervene between the integrally molded structure and the chassis, in the form of exterior facing integrated with the internal frame structure  7748   b . Thus, in the first modification example of  FIG. 121(B) , the internal frame structure  7748   b  which constitutes the majority of the weight of the mobile telephone  7701   b  is connected to the integrally molded structure of the cartilage conduction units  7424 ,  7426  and the linking unit  7427 , serving to suppress vibration of the chassis constituting the outer face of the mobile telephone  7701   b , due to the chassis being held by the internal frame structure  7748   b  via the vibration isolating material  7765 . 
       FIG. 121(C)  is a side sectional view relating to a second modification example of the eighty-first embodiment according to an aspect of the present invention, configured as a mobile telephone  7701   c . The second modification example of  FIG. 121(C)  has much in common with the first modification example of  FIG. 121(B) , and therefore the same reference numerals are assigned to common portions, and descriptions thereof are omitted. 
     A point of difference between the second modification example of  FIG. 121(C)  and the first modification example of  FIG. 121(B)  is that the elastic body interposed between an internal frame structure  7748   c  and the integrally molded structure of the cartilage conduction units  7424 ,  7426  and the linking unit  7427  has been omitted. In cases in which vibration suppression due to an acoustic impedance differential of the integrally molded structure and the internal frame structure  7748   c  does not appreciably extend to the integrally molded structure, and satisfactory cartilage conduction can be ensured, it is possible to adopt such a simplified, direct-connection configuration. That is, in cases in which priority is given to reducing the number of parts, even at the expense of some cartilage conduction efficiency, to simplify the connection structure of the integrally molded structure and the internal frame structure  7748   c , it is possible to adopt the configuration of the second modification example. 
     In the above manner, in the first modification example of  FIG. 121(B)  or the second modification example of  FIG. 121(C) , in the first instance, the internal frame structure  7748   b  or  7748   c , which constitutes a majority of the weight, is connected to the integrally molded structure of the cartilage conduction units  7424 ,  7426  and the linking unit  7427 , suppressing vibration. The chassis, which represents a small proportion of the weight, is then connected to the internal frame structure  7748   b  or  7748   c  via the vibration isolating material, suppressing vibration of the chassis constituting the outside surface of the mobile telephone  7701   b  or  7701   c.    
     Various modifications of the aforedescribed embodiments are possible provided that the advantages thereof can be enjoyed while doing so. For example, in the seventy-eighth embodiment of  FIG. 118 , in cases in which the elastic body  7465  has high vibration isolating effect, the integrally molded structure of the cartilage conduction units  7424 ,  7426  and the linking unit  7427 , and the chassis of the mobile telephone  7401 , may be configured of materials having the same acoustic impedance (for example, a common material for both). In in cases in which the elastic body  7465  has high vibration isolating effect, there can be achieved a state comparable to one of different acoustic impedance between the integrally molded structure of the cartilage conduction units  7424 ,  7426  and the linking unit  7427 , and the chassis of the mobile telephone  7401 , due to interposition of the elastic body  7465 , whereby satisfactory cartilage conduction can be obtained, in spite of vibration suppression of the chassis due to the weight of the cell  7448  being connected thereto. 
     The features of the present invention described above are not limited to implementation in the aspects in the aforedescribed embodiments, and may be implemented in other aspects as well, provided that the advantages thereof can be enjoyed by doing so. For example, the structures of the eightieth embodiment shown in  FIG. 120  and the second modification example of the eighty-first embodiment shown in  FIG. 121(C)  are not limited to cases in which the cartilage conduction units are made of hard material, and are also suitable in cases in which the cartilage conduction units are elastic bodies, as in, for example, the forty-sixth embodiment of  FIG. 69 , and the modification example thereof in  FIG. 71 . The reason is that a cartilage conduction unit made of an elastic body will have greatly different acoustic impedance from the chassis, and even when the weight of the internal structure of the mobile telephone is connected to the chassis in proximity to the cartilage conduction unit, cartilage conduction by the cartilage conduction unit will not be impaired. In a case of applying the eightieth embodiment of  FIG. 120  to a structure in which the cartilage conduction vibration source (piezoelectric bimorph element)  2525  is supported from both sides by left and right cartilage conduction units (the elastic body units  4263   a ,  4263   b ) as in the forty-sixth embodiment and the modification example thereof, the upper holder  7406  may be extended towards the left-ear cartilage conduction unit (elastic body unit  4263   a ) side, and the pins  7408  arranged not just in proximity to the elastic body unit  4263   b , but in proximity to the elastic body unit  4263   a  as well. 
     Eighty-Second Embodiment 
       FIG. 122  is a block diagram relating to an eighty-second embodiment according to an aspect of the present invention, and is constituted as a cartilage conduction vibration source device for a mobile telephone. The eighty-second embodiment has much in common with the seventy-sixth embodiment of  FIG. 116 , and therefore the same reference numerals are assigned to common portions, omitting descriptions thereof unless necessary. Like the seventy-sixth embodiment of  FIG. 116 , the eighty-second embodiment provides a cartilage conduction vibration source device controllable by the application processor  7039  and the power management circuit  7053  in an ordinary mobile telephone, and more specifically, one in which the cartilage conduction vibration source device is configured as a piezoelectric bimorph element  7013  and a driver circuit  7503  therefor. There are differences between the eighty-second embodiment of  FIG. 122  and the seventy-sixth embodiment of  FIG. 116 , in terms of the configuration of a digital acoustic processing circuit  7538 , and of gain control in an analog output amp  7540 . 
     Firstly, the configuration of the digital acoustic processing circuit  7538  is described. Cartilage conduction can be defined as cartilage conduction in a broad sense or as cartilage conduction in a narrow sense. Cartilage conduction in a broad sense may be defined as sound output from a cartilage conduction unit, including cartilage-air conduction (the rate at which vibration transmitted from a cartilage conduction unit to cartilage of the ear changes to air conduction within the external auditory meatus, and is propagated to the inner ear through the eardrum), cartilage-bone conduction (the rate at which vibration transmitted from a cartilage conduction unit to cartilage of the ear is propagated directly to the inner ear through bone), and direct air conduction (the rate at which air-conducted sound generated from a cartilage conduction unit reaches the eardrum directly without going through cartilage, and is propagated to the inner ear). In contrast to this, cartilage conduction in the narrow sense is defined as sound propagated to the inner ear through cartilage, and includes the aforedescribed cartilage-air conduction and cartilage-bone conduction. 
     In a normal individual, the proportions of cartilage-air conduction and cartilage-bone conduction in cartilage conduction in the narrow sense are such that the latter is about 1/10 or less of the former, and thus cartilage-air conduction is extremely important. This is due to extremely poor impedance matching from cartilage to bone. In contrast to this, in a person with conductive hearing loss due to an abnormality of the external auditory meatus or middle ear, the proportion of cartilage-bone conduction is greater, as compared with a normal individual. This due to impaired cartilage-air conduction (and of course direct air conduction as well). 
     Next, with regard to the rate of participation by cartilage-air conduction in the broad sense, as described above, in a normal individual, participation by cartilage-bone conduction is small, and therefore one may focus substantially upon the proportions of cartilage-air conduction and direct air conduction. As a rule of thumb, cartilage-air conduction predominates in low-pitched regions, while direct air conduction predominates in high-pitched regions; at 500 Hz, substantially all conduction is cartilage-air conduction, while at 4000 Hz, substantially all conduction is direct air conduction. The frequency components necessary to discriminate some consonants such as the “sh” sound lie in a high frequency band close to 4000 Hz in which direct air conduction predominates. In mobile telephones, due to the fact that there are no problems whatsoever in terms of language discrimination during conversation, and to concerns relating to the amount of information, frequency components of about 3000 Hz and above are cut, so the importance of cartilage-air conduction is great. 
     With regard to cartilage-bone conduction, as described above, in a normal individual, the participation of cartilage-bone conduction in the broad sense is small, and it is thought that the frequency characteristics thereof are substantially close to flat from a low-frequency range to a high-frequency range. Incidentally, when there is a transition from an occluded condition to an unoccluded condition in the external auditory meatus, in low-frequency bands (500 Hz or the like), sound pressure within the external auditory meatus drops, but loudness (the perceived magnitude of sound) does not drop as much as the sound pressure. When there is a transition from an unoccluded condition to an occluded condition in the external auditory meatus, in high-frequency bands, sound pressure within the external auditory meatus drops, but loudness does not drop as much as the sound pressure within the external auditory meatus. This fact suggests that cartilage-bone conduction exists in both low-frequency bands and high-frequency bands, albeit to a very small extent. 
     In the digital acoustic processing circuit  7538  of  FIG. 122 , taking into account the frequency characteristics of cartilage-air conduction, cartilage-bone conduction, and direct air conduction in cartilage conduction in the broad sense described above, in combination with the degrees of participation thereof, a digital sound signal output from the application processor  7039  is input respectively to a cartilage-bone conduction equalizer  7538   a , a cartilage-air conduction equalizer  7538   b , and a direct air conduction equalizer  7538   c , which respectively perform optimal equalization in cases of cartilage-bone conduction only, cartilage-air conduction only, and direct air conduction only. Equalization here does not refer to equalization for the purpose of obtaining sounds closely approximating natural sounds, but rather to acoustic processing taking into account the frequency characteristics of the piezoelectric bimorph element  7013  serving as the cartilage conduction vibration source, in combination with the frequency characteristics in the respective transmission rates of cartilage-bone conduction, cartilage-air conduction, and direct air conduction, to propagate sound in the most efficient manner in terms of language discrimination ability. Consequently, equalization would include cases in which precedence is given to language discrimination ability, modifying the voice quality somewhat from its natural state, but not to the extent that the ability to identify the person is impaired. 
     In accordance with an instruction from the application processor  7039 , a synthesis unit  7538   d  of the digital acoustic processing circuit  7538  determines a mixing ratio of the outputs from the cartilage-bone conduction equalizer  7538   a , the cartilage-air conduction equalizer  7538   b , and the direct air conduction equalizer  7538   c , and modifies this ratio according to changes in conditions. The mixing ratio, which is directed in the first instance to a normal individual, is determined based on the frequency characteristics of a conversation taking place in a case in which the cartilage conduction unit is contacting the ear cartilage and the external auditory meatus is not occluded, but is modified when there is a change from this state. In specific terms, since sound not produced in the course of a call, such as playback of a voice memo, will not be cut off at 3000 Hz and above, the extent of participation of the direct air conduction equalizer  7538   c  is boosted. In a case in which the device has been set for use by a person with conductive hearing loss, the element relying on bone conduction is greater, and therefore the extent of participation of the cartilage-bone conduction equalizer  7538   a  is boosted. Further, when the occurrence of an earplug bone conduction effect has been detected, this means that external auditory meatus is occluded and that there is no direct air conduction, and therefore the participation of the direct air conduction equalizer  7538   c  is halted. The details of these processes are discussed below. 
     Next, automatic gain adjustment by the analog output amp  7540  will be described. A maximum input rating at which the piezoelectric bimorph element  7013  is capable of vibrating has been specified, and in the event that a signal exceeding this is output from the analog output amp  7540 , the sound becomes distorted, and bone conduction at the desired frequency characteristics cannot be achieved. On the other hand, in a case in which the maximum output from the analog output amp  7540  falls below the maximum input rating of the piezoelectric bimorph element  7013 , cartilage conduction that fully exploits the capabilities of the piezoelectric bimorph element  7013  cannot be achieved. A gain control unit  7540   a  sequentially monitors the average output of the DA converter  7138   c  for a predetermined duration, and controls a gain adjustment unit  7540   b  of the analog output amp  7540 , doing so in such a way that the output level of the analog output amp  7540  equals the maximum input rating level of the analog output amp  7540 . In so doing, the capabilities of the piezoelectric bimorph element  7013  can be utilized to the maximum, and bone conduction at the desired frequency characteristics can be achieved. 
       FIG. 123  is a flowchart showing the functions of the application processor  7039  in the eighty-second embodiment of  FIG. 122 . The flow in  FIG. 123  describes the functions of the driver circuit  7503 , and therefore operations centered on related functions have been extracted for illustration; however, there are other operations of the application processor  7039 , such as typical functions of mobile telephones and like, which are not represented in the flow of  FIG. 123 . The flow of  FIG. 123  starts when the main power source of the mobile telephone is turned on. In Step S 412 , initial startup and a function check of each unit are performed, as well as initiating screen display on a display unit of the mobile telephone. Next, in Step S 414 , the cartilage conduction unit and mobile telephone outgoing-talk unit functions are turned off, and the routine advances to Step S 416 . Turning off of the cartilage conduction units is accomplished by turning off the power supply to the driver circuit  7503  from the power management circuit  7053  of  FIG. 122 . 
     In Step S 416 , a check is performed to determine if an operation to playback a previously recorded voice memo has been performed. In the event that no voice memo playback operation has been detected, the routine proceeds to Step S 418 , and a check is performed to determine if the current state is one in which another caller&#39;s answer to a telephone call request, or a call through mobile radio waves based on an incoming call, is in progress. When the current state is the talk state, the routine proceeds to Step S 420 , the cartilage conduction units and the outgoing-talk unit are turned on, and routine proceeds to Step S 422 . 
     In Step S 422 , a check is performed to determine if a setting for a person with conductive hearing loss has been made, and in the event that this setting has not been made, the routine advances to Step S 424 . In Step S 424 , a check is performed to determine if the current state is one in which an earplug bone conduction effect has arisen due to closing of the external auditory meatus, and in the event this is not the case, the routine proceeds to Step S 426 , and advances to Step S 428 , without applying a signal in which the waveform of the user&#39;s own voice is inverted. The process of application/non-application of a waveform-inverted signal of the user&#39;s own voice has been described in Step S 52  to Step S 56  in the flow of  FIG. 10 , and therefore the details are omitted here. In Step S 428 , proportions of participation by the respective outputs of the equalizers  7538   a ,  7538   b , and  7538   c  are set to optimal values for the talk state appropriate to a normal individual, and the routine advances to Step S 430 . 
     On the other hand, when a state in which the earplug bone conduction effect has occurred due to closing of the external auditory meatus is detected in Step S 424 , the routine advances to Step S 431 , and a waveform-inverted signal of the user&#39;s own voice is added; also, in Step S 432 , participation by the direct air conduction equalizer  7538   c  is halted, whereupon the routine advances to Step S 430 . As noted previously, the reason for doing so is that there is no direct air conduction, due to closure of the external auditory meatus. In a case in which it has been detected in Step S 422  that a setting for a person with conductive hearing loss has been made, the routine advances to Step S 434 , the extent of participation by the cartilage-bone conduction equalizer  7538   a  is boosted, and routine advances to Step S 430 . 
     In Step S 430 , a check is performed to determine whether the call has ended, and in the event this is not the case, returns to Step S 422 , and repeats Step S 422  to Step S 434  for as long as the call has not ended. In so doing, participation by the respective outputs of the equalizers  7538   a ,  7538   b , and  7538   c  can be modified in response to changes in settings or conditions during a call. On the other hand, in the event that the call is detected to have ended in Step S 430 , the routine advances to Step S 436 , the cartilage conduction unit and the outgoing-talk unit functions are turned off, and routine proceeds to Step S 438 . 
     In contrast to this, in the event that a voice memo playback operation has been detected in Step S 416 , the routine advances to Step S 440 , and the extent of participation by the direct air conduction equalizer  7538   c  is boosted. The reason is that, in the aforedescribed manner, since sound not produced in the course of a call, such as that of playback of a voice memo, is not cut off at 3000 Hz and above, in terms of sound quality, it is appropriate to boost participation by direct air conduction. Next, in Step S 442 , the cartilage conduction units are turned on, the routine advances to Step S 444 , and a voice memo playback process is performed. Then, once the voice memo playback process is finished, the routine advances to Step S 446 , the cartilage conduction unit is turned off, and routine advances to Step S 438 . When the talk state is not detected in Step S 418 , the routine advances directly to Step S 438 . 
     In Step S 438 , a check performed to determine whether the main power source of the mobile telephone has been turned off, and in the event that the main power source is not off, Step S 416  to Step S 446  are subsequently repeated according to circumstances, for as long as turning off of the main power source is not detected in Step S 438 . In contrast to this, in the event that turning off of the main power source is detected in Step S 438 , the flow terminates. 
     Eighty-Third Embodiment 
       FIG. 124  is a perspective view relating to an eighty-third embodiment of an aspect of the present invention, and is configured as a notebook-type large-screen mobile telephone  7601  equipped with mobile telephone functionality.  FIG. 124(A)  is a front view of the mobile telephone  7601 . The mobile telephone  7601  is provided with a large-screen display unit  7605  that doubles as a touch panel. The mobile telephone  7601  is further provided with a cartilage conduction outgoing-talk/incoming-talk unit  7681  connected to the right edge thereof by a universal joint  7603 . The cartilage conduction outgoing-talk/incoming-talk unit  7681 , at its upper end, constitutes a cartilage conduction unit  7624 , and is furnished in its medial section with a microphone  7623 . As discussed below, the cartilage conduction outgoing-talk/incoming-talk unit  7681  has as structure whereby it is possible for the cartilage conduction unit  7624  to be withdrawn upward; in  FIG. 124(A) , however, the cartilage conduction outgoing-talk/incoming-talk unit  7681  is shown in the stowed state in which it is basically not being used. 
       FIG. 124(B)  shows a state in a case in which the mobile telephone functionality of the mobile telephone  7601  is being utilized; it will be appreciated that it is possible for the cartilage conduction unit  7624  to be withdrawn upward as shown by an arrow  7681   a , as well as for the cartilage conduction unit  7624  to be lowered forward as shown by an arrow  7681   b . Because the cartilage conduction outgoing-talk/incoming-talk unit  7681  is connected to the mobile telephone  7601  by the universal joint  7603  in the aforedescribed manner, the direction of lowering is not limited to the forward direction, and lowering can take place in any direction. 
     Due to the aforedescribed configuration, with the mobile telephone  7601 , for example, placed on a desktop and maintained in an orientation such that content displayed on the large-screen display unit  7605  (such as newspapers, e-books, graphics, or the like) can be viewed, the withdrawn cartilage conduction unit  7624  can be placed by hand against the cartilage of the ear, so that calls can be made by the mobile telephone. At this time, one&#39;s own voice can be picked up by the microphone  7623 , which is positioned close to the mouth during the call state. However, there is no limitation to this orientation, and it would be possible, while holding the mobile telephone  7601  in the hand, to appropriately adjust the withdrawn length and direction of the cartilage conduction outgoing-talk/incoming-talk unit  7681 , to place the cartilage conduction unit  7624  against the cartilage of the ear. The cartilage conduction unit  7624  is designed such that, even with the mobile telephone  7601  placed on the knees, by virtue of a structure resembling that of an antenna, the withdrawn length thereof is likewise sufficient to deal with such a case. 
     When the mobile telephone  7601  is used in the state shown in  FIG. 124(A) , when there is an incoming call to the mobile telephone, the call can be answered instantaneously by withdrawing the cartilage conduction outgoing-talk/incoming-talk unit  7681 . Further, when the operation of withdrawing the cartilage conduction outgoing-talk/incoming-talk unit  7681  is interlinked to the operation of answering the incoming call, one-touch operation is possible, further improving the ease of use. Likewise, when one wishes to place a mobile telephone call while using the mobile telephone  7601  in the state shown in  FIG. 124(A) , after performing an operation from the touch panel/large-screen display unit  7605  to choose a contact to be called, the cartilage conduction outgoing-talk/incoming-talk unit  7681  is withdrawn and placed against the ear. At this time, when the operation of withdrawing the cartilage conduction outgoing-talk/incoming-talk unit  7681  is interlinked to the call request operation, the call can be placed through a one-touch operation. 
     In  FIG. 124(B) , the mobile telephone is shown being used in an orientation in which the screen is viewed in landscape mode, but it would be possible to use the unit in portrait mode as well. For example, when used in portrait mode with the cartilage conduction outgoing-talk/incoming-talk unit  7681  side upward, the cartilage conduction outgoing-talk/incoming-talk unit  7681  may be used by extending it to reach the cartilage of the ear from the upper right corner of the portrait-oriented screen. Both in the case of a landscape-oriented screen and portrait-oriented screen, the cartilage conduction unit  7624  may be used while placed against the cartilage of the right ear, but the mobile telephone  7601  can be rotated to an orientation affording ease of listening with the left ear. For example, when the unit is used in landscape mode with the cartilage conduction outgoing-talk/incoming-talk unit  7681  side downward, the cartilage conduction outgoing-talk/incoming-talk unit  7681  can be used by extending it to reach the cartilage of the left ear from the lower left corner of the portrait-oriented screen. Further, when used in landscape mode flipped top to bottom from the state shown in  FIG. 124(B) , the cartilage conduction outgoing-talk/incoming-talk unit  7681  can be used by extending it to reach the cartilage of the left ear from the upper left corner of the landscape-oriented screen. In either case, because the cartilage conduction unit  7624  is linked to the mobile telephone  7601  by the universal joint  7603  and the cartilage conduction outgoing-talk/incoming-talk unit  7681 , which is extendable and retractable from the mobile telephone  7601  without being separated therefrom, the configuration is easy to use, even during use while being carried around. 
       FIG. 125  is a perspective view showing a modification example of the eighty-third embodiment of  FIG. 124 , and like the eighty-third embodiment, is configured as a notebook-type large-screen mobile telephone  7701  equipped with mobile telephone functionality. A point of difference between the modification example of  FIG. 125  and the eighty-third embodiment of  FIG. 124  is that the device is provided with a cartilage conduction outgoing-talk/incoming-talk unit  7781  connected by a universal joint  7703  at the upper right corner of the right edge of a touch panel/large-screen display unit  7705  when used in portrait mode. As a result, the cartilage conduction unit  7624  is situated at the bottom end of the cartilage conduction outgoing-talk/incoming-talk unit  7781 . In this modification example, a microphone  7723  is furnished on the main body side of the mobile telephone  7701 . 
     Due to the aforedescribed structure, it is possible for the cartilage conduction unit  7724  to be drawn downward as shown by an arrow  7781   a , as well as raised forward as shown by an arrow  7781   b . As the cartilage conduction outgoing-talk/incoming-talk unit  7781  is connected to the mobile telephone  7701  by the universal joint  7701  in the same manner as in the eighty-third embodiment of  FIG. 124 , the direction of raising is not limited to a forward direction, and raising can take place in any direction. In the case of the modification example of  FIG. 125 , when used as illustrated in the portrait mode, the cartilage conduction outgoing-talk/incoming-talk unit  7781  is used by extending it to reach the cartilage of the right ear from the upper right corner of the portrait-oriented screen. In contrast to this, when, for example, used in landscape screen mode with the cartilage conduction outgoing-talk/incoming-talk unit  7781  side down, the cartilage conduction outgoing-talk/incoming-talk unit  7781  is used by extending it to reach the cartilage of the right ear from the lower right corner of the landscape-oriented screen. The modification example of  FIG. 125 , like the eighty-third embodiment of  FIG. 124 , can be used easily while placed against the left ear in either portrait screen mode or landscape screen mode, through appropriate rotation of the screen. 
     In both the eighty-third embodiment of  FIG. 124  and the modification example thereof in  FIG. 125 , the cartilage conduction unit may be configured from a piezoelectric bimorph element, or configured from an electromagnetic vibrator. The structure of the eighty-third embodiment of  FIG. 124  and the modification example thereof in  FIG. 125  is not limited to a cartilage conduction system, and a configuration in which an earphone comprising an ordinary air-conduction speaker is attached at the location of the cartilage conduction unit would also be acceptable. 
     Implementation of the present invention is not limited to the aforedescribed embodiments, and the various advantages of the present invention can be enjoyed in other embodiments as well. Further, these features may be interchanged or utilized in combination among various embodiments. For example, in the eighty-second embodiment shown in  FIG. 122  and  FIG. 123 , the cartilage-bone conduction equalizer  7538   a , the cartilage-air conduction equalizer  7538   b , and the direct air conduction equalizer  7538   c  are respectively shown as hardware blocks, but identical functions could be accomplished through digital acoustic processing circuit software as well. Further, in the configuration in the eighty-second embodiment, modification of the equalizers according to conditions entails modifying the mixing ratios of the outputs of three equalizers; however, provided that the final output of the digital acoustic processing circuit  7538  is comparable, modification of the equalizers may be performed in block. 
     Eighty-Fourth Embodiment 
       FIG. 126  is a perspective view and a cross sectional view relating to an eighty-fourth embodiment according to an aspect of the present invention, configured as an ordinary mobile telephone  7801  and cartilage conduction soft cover  7863  therefor.  FIG. 126(A)  is a perspective view of the ordinary mobile telephone  7801  of the eighty-fourth embodiment and the sheathing cartilage conduction soft cover  7863 , seen from the front face. Due to the elasticity of the cartilage conduction soft cover  7863 , the ordinary mobile telephone  7801  is protected in the event that the ordinary mobile telephone  7801  is dropped by accident or the like, and the upper right side corner of the cover also serves as a cartilage conduction unit  7824 , as will be discussed below. The ordinary mobile telephone  7801  is a mobile telephone of ordinary smartphone type, having a microphone  23  and an earphone  213  comprising an air-conduction speaker. The left upper part of the mobile telephone  7801  is furnished with an external earphone jack for an external earphone. Meanwhile, the cartilage conduction soft cover  7863  is furnished with an external earphone plug  7885 ; sound signals for vibrating the cartilage conduction unit  7824  are conducted from the external earphone plug  7885  which is plugged into the external earphone jack. 
     To sheath the ordinary mobile telephone  7801  in the cartilage conduction soft cover  7863 , firstly, the cartilage conduction soft cover  7863  is turned nearly inside-out, and the external earphone plug  7885  is inserted into the external earphone jack; thereafter, the ordinary mobile telephone  7801  in its entirety is sheathed in the cartilage conduction soft cover  7863 . Once the external earphone plug  7885  has been inserted into the external earphone jack from the outside, sound output from the earphone  213  turns off, and sound signals for vibrating the cartilage conduction unit  7824  are output from the external earphone jack. Because a portion of the cartilage conduction soft cover  7863  constitutes the cartilage conduction unit  7824 , an elastic material having acoustic impedance close to that of ear cartilage (silicone rubber, mixtures of silicone rubber and butadiene rubber, natural rubber, or structure of these with air bubbles sealed therein) is adopted. 
       FIG. 126(B)  is a cross-sectional view of an upper part of the cartilage conduction soft cover  7863  taken in B 1 -B 1  cross section in  FIG. 126(A) , through a plane perpendicular to the front surface and the side faces of the cartilage conduction soft cover  7863 . From  FIG. 126(B)  it will be clear that the upper right side corner of the cartilage conduction soft cover  7863  constitutes the cartilage conduction unit  7824 , and an electromagnetic vibrator  7825  constituting a cartilage conduction vibration source is embedded to the inside thereof. The upper part of the cartilage conduction soft cover  7863  is furnished with a conduction part driver  7840  for driving the electromagnetic vibrator  7825 , and with a replaceable power source cell  7848  for supplying power thereto. The electromagnetic vibrator  7825  vibrates when driven by the conduction part driver  7840  on the basis of a sound signal input from the external earphone plug  7885 . The direction of vibration is a direction perpendicular to a large-screen display unit  7805  of the ordinary mobile telephone  7801  (see  FIG. 126(A) ) as shown by an arrow  7825   a.    
       FIG. 126(C)  is a cross-sectional view of an upper part of the cartilage conduction soft cover  7863  taken in B 21 -B 2  cross section in  FIG. 126(A)  or  FIG. 126(B) , through a plane perpendicular to the front surface and the top face of the ordinary mobile telephone  7801  and the cartilage conduction soft cover  7863 . As will be appreciated from  FIG. 126(C) , by sheathing the ordinary mobile telephone  7801  in the cartilage conduction soft cover  7863 , the electromagnetic vibrator  7825  serving as the cartilage conduction vibration source is integrated with the ordinary mobile telephone  7801 , and vibrates in response to the sound signal supplied by the external earphone plug  7885 . In so doing, simply by sheathing the ordinary mobile telephone  7801  in the cartilage conduction soft cover  7863  without making any additional modifications, the unit can be transformed into a cartilage conduction type mobile telephone similar, for example, to the sixtieth embodiment of  FIG. 90 . 
     In the eighty-fourth embodiment of  FIG. 126 , when the ordinary mobile telephone  7801  is sheathed in the cartilage conduction soft cover  7863  in the aforedescribed manner, the cartilage conduction unit  7824  is formed exclusively in the right side corner as seen in the drawing. This state is one suitable for making a call while holding the ordinary mobile telephone  7801  with the right hand and listening with the right ear. To hold the unit with the left hand and listen with the left ear, the ordinary mobile telephone  7801  would be switched between hands so as to face it rearward and thereby face the cartilage conduction unit  7824  towards the left ear, in the manner described in the twelfth embodiment of  FIG. 22  and the thirty-sixth embodiment of  FIG. 56 . 
       FIG. 127  is a block diagram of the eighty-fourth embodiment of  FIG. 126 . In the block diagram, the ordinary mobile telephone  7801  has much in common with the ordinary mobile telephone  1601  in the sixty-ninth embodiment of  FIG. 102 , and therefore the same reference numerals have been assigned to common parts, and descriptions are omitted. A point of difference between  FIG. 127  and  FIG. 102  is that the short-range communication unit  1446  has been omitted from the illustration in  FIG. 127 , while an external earphone jack  7846  is illustrated. However, this does not mean that the ordinary mobile telephone  1601  of  FIG. 102  and the ordinary mobile telephone  7801  of  FIG. 127  are in fact different, but merely that appropriate omission of illustration has been made, as required by the description. 
     As will be clear from the block diagram of  FIG. 127 , in a state in which the ordinary mobile telephone  7801  has been sheathed in the cartilage conduction soft cover  7863 , the external earphone plug  7885  is inserted into the external earphone jack  7846  of the ordinary mobile telephone  7801 , and the conduction unit driver  7840  drives the electromagnetic vibrator  7825  on the basis of sound signals output from an incoming-talk-processing unit  212  of the ordinary mobile telephone  7801 . 
       FIG. 128  is cross sectional views showing a modification example of the eighty-fourth embodiment of  FIG. 126 . Common reference numerals have been assigned to portions in common with  FIG. 126 , omitting descriptions thereof, and describing only the different portions.  FIG. 128(A)  is a cross sectional view of the cartilage conduction soft cover  7963  sheathing the ordinary mobile telephone  7801 , seen from the front face, with the upper part split lengthwise. As will be clear from  FIG. 128(A)  and  FIG. 128(B) , the cartilage conduction soft cover  7863  of the modification example is furnished with a cavity  7963   a , and an external earphone plug  7985  is arranged in such a way as to be able move freely within the cavity  7963   a . Consequently, prior to sheathing the ordinary mobile telephone  7801  in the cartilage conduction soft cover  7963 , the external earphone plug  7985  readily inserts into the external earphone jack  7846 . Then, once it is confirmed that the external earphone plug  7985  has been correctly inserted into the external earphone jack  7846  of the ordinary mobile telephone  7801 , the ordinary mobile telephone  7801  can be sheathed within the cartilage conduction soft cover  7863 . 
     A second point of difference between the modification example of  FIG. 128  and the eighty-fourth embodiment of  FIG. 126  is that the cartilage conduction soft cover  7963  is furnished with a relay external earphone jack  7946 . In so doing, despite the fact that the original external earphone jack  7846  of the ordinary mobile telephone  7801  is obstructed, in cases in which it is desired to listen to music or the like, it is possible to use the unit in the customary manner, through insertion of an ordinary external earphone or the like into the relay external earphone jack  7946 . The relay external earphone jack  7946  is furnished with a switch  7946   a  which, in a case in which a sound signal is being propagated from the external earphone plug  7985  to the conduction unit driver  7840 , and an ordinary external earphone or the like has been inserted into the relay external earphone jack  7946 , will ordinarily switch the sound signal from the external earphone plug  7985  so as to be output from the relay external earphone jack  7946 . 
       FIG. 129  is a block diagram of a modification example of the eighty-fourth embodiment of  FIG. 128 . Common reference numerals have been assigned to portions in common with ones in the eighty-fourth embodiment of  FIG. 127 , and descriptions thereof are omitted. Identical reference numerals have been assigned also to portions identical to  FIG. 128 , omitting descriptions unless necessary. As will be clear from  FIG. 129 , a sound signal from the external earphone plug  7985  is branched by the switch  7946   a ; ordinarily, the sound signal will be propagated from the external earphone plug  7985  to the conduction unit driver  7840  while mechanically detecting insertion of an ordinary external earphone or the like into the relay external earphone jack  7946 , to thereby switch the sound signal from the external earphone plug  7985  by a mechanical switch, so as to be output from the relay external earphone jack  7946 . 
     Eighty-Fifth Embodiment 
       FIG. 130  is a perspective view and a cross sectional view relating to an eighty-fifth embodiment according to an aspect of the present invention, and to a modification example thereof, configured as a mobile telephone  8001  or  8001   x . The eighty-fifth embodiment of  FIG. 130  has much in common with the fifty-fifth embodiment of  FIG. 83 , and therefore the same reference numerals have been assigned to common parts, and descriptions are omitted. The eighty-fifth embodiment of  FIG. 130  differs from the fifty-fifth embodiment of  FIG. 83  in that only the right cartilage conduction unit  5124  at the right side in the drawing is provided, and in terms of the associated configuration of a microphone  8023  or  8123 . 
     As will be clear from  FIG. 130(A)  and from  FIG. 130(B)  showing a B 1 -B 1  cross section thereof, in the eighty-fifth embodiment, the cartilage conduction unit  5124  is furnished at one side only. Consequently, in the same manner as the twelfth embodiment of  FIG. 22 , the thirty-sixth embodiment of  FIG. 56 , and the eighty-fourth embodiment of  FIG. 126 , in the illustrated state, the cartilage conduction unit  5124  is used while held against the right ear, but may be switched between hands so that the mobile telephone faces  8001  rearward, in order to use the cartilage conduction unit  5124  while held against the left ear. In association therewith, the user&#39;s mouth will be positioned to the front surface side, or to the rear surface side, of the mobile telephone  8001 . 
     As will be clear from  FIG. 130(A) , to accommodate use of the cartilage conduction unit  5124  from both the front and back sides in this manner, the microphone  8023  is furnished in lower part of the right side surface of the mobile telephone  8001 . The microphone  8023  is configured such that directionality  8023   a  to pick up sound from the front surface side and directionality  8023   b  to pick up sound from the rear surface side are symmetrical, and such that the voice is picked up evenly from the rear side. In so doing, the user&#39;s voice can be picked up evenly, both in cases in which a call is made with the cartilage conduction unit  5124  placed against the right ear so that the front surface side of the mobile telephone  8001  is opposed to the face, and in cases in which a call is made with the cartilage conduction unit  5124  placed against the left ear so that the rear surface side of the mobile telephone  8001  is opposed to the face. 
       FIG. 130(C)  is a modification example of the eighty-fifth embodiment, showing the mobile telephone  8001   x  viewed from the bottom surface side. This modification example of the eighty-fifth embodiment differs only in the placement of the microphone  8123 , and in other respects is identical to the eighty-fifth embodiment; therefore only the bottom surface is shown in  FIG. 130(C) , omitting the rest from the illustration. As will be clear from  FIG. 130(C) , in the modification example of the eighty-fifth embodiment, the microphone  8123  is furnished at the right side of the lower surface of the mobile telephone  8001   x . In the same manner as in the eighty-fifth embodiment, the microphone  8123  is constituted such that directionality  8123   a  to pick up sound from the front surface side and directionality  8123   b  to pick up sound from the rear surface side are symmetrical. In so doing, in the modification example as well, the user&#39;s voice can be picked up evenly, both in cases in which a call is made from the front surface side of the mobile telephone  8001   x , and cases in which a call is made from the rear surface side. It goes without saying that the cartilage conduction unit  5124  can be employed in common, in both instances. 
     The features of the present invention described above are not limited to implementation in the aforedescribed embodiments, and are implementable in other aspects provided that the advantages thereof can be enjoyed. For example, in the eighty-fourth embodiment of  FIG. 126 , the left side in the drawing is not furnished with a cartilage conduction unit, in order that the external earphone plug  7885  may be placed there; however, in cases in which no connection terminal for a sound signal from the external earphone pack  7846  or the like is present at the upper surface of the ordinary mobile telephone  7801 , it would be possible, utilizing the space on the upper surface, to have cartilage conduction units at both the left and right corners. While a separate power source cell  7848  was provided for operation of the conduction unit driver  7840 , in cases in which the external output level of the ordinary mobile telephone  7801  is sufficient for direct driving of the cartilage conduction unit  7824 , it would be possible to omit the power source. In cases in which power source supply is not necessary for operation of the conduction unit driver  7840 , or in cases in which an output terminal of the ordinary mobile telephone  7801  is configured such that power source supply together with the sound signal is possible, there is no need to have the separate power source cell  7848 . Further, in the eighty-fourth embodiment, the electromagnetic vibrator  7825  was adopted as the cartilage conduction vibration source, but there is no limitation to this, and a piezoelectric bimorph element may be adopted as the cartilage conduction vibration source, as in other embodiments, as long as it is possible for the conduction unit driver  7840  to operate on the basis of power supply from a separate power source or from the ordinary mobile telephone  7801 . 
     In the eighty-fourth embodiment of  FIG. 126 , the mobile telephone accessory device for vibrating the cartilage conduction unit on the basis of external audio output of the ordinary mobile telephone was configured as a soft cover; however, implementation of the present invention is not limited to this. For example, depending on the shape of the mobile telephone and the placement of the external audio output terminal, the device may be configured as a hard case type mobile telephone accessory device of a shape that clips onto the upper part of the mobile telephone. In this case, when an external earphone jack is situated in the upper part of the mobile telephone, it is possible to utilize an external earphone plug section inserted into the external earphone plug section, to position the mobile telephone accessory device and to support it in the clipped state. 
     In the eighty-fifth embodiment of  FIG. 130 , depending on the directionality settings of the microphone  8023  or  8123 , there is a significant possibility of picking up outside noise; however, in cases in which the environment-noise microphone of the first example of  FIG. 1  or the fiftieth embodiment of  75  is provided, this could be utilized to cancel the outside noise. 
     Eighty-Sixth Embodiment 
       FIG. 131  is a block diagram relating to an eighty-sixth embodiment according to an aspect of the present invention, configured as a mobile telephone  8101 . The block diagram of  FIG. 131  relating to the eighty-sixth embodiment has much in common with the block diagram of  FIG. 82  relating to the fifty-fourth embodiment, and therefore identical reference numerals have been assigned to identical portions, and descriptions are omitted. The eighty-sixth embodiment of  FIG. 131  differs from the fifty-fourth embodiment of  FIG. 82  in terms of the configuration of a cartilage conduction equalizer  8138 , the details of which are discussed below. Additionally,  FIG. 131  depicts an external earphone jack  8146  for connecting an earphone to listen to sound from an incoming-call processing unit  212 , and a short-range wireless communication unit  8147  for short-range wireless communication with a mobile telephone accessory device, such as a headset designed to be worn on the head. 
     Next, employing  FIG. 132 , the functions of the cartilage conduction equalizer  8138  in the eighty-sixth embodiment of  FIG. 131  will be described.  FIG. 132(A)  is an image diagram of the frequency characteristics of a piezoelectric bimorph element constituting a cartilage conduction vibration source in a cartilage conduction vibration unit  228  employed in the eighty-sixth embodiment, showing the results of measurements of vibrational acceleration level at each frequency. As will be clear in  FIG. 132(A) , the piezoelectric bimorph element vibrates strongly in a frequency band of 800 Hz and above, but exhibits generally flat frequency characteristics up to about 10 kHz, aside from a few peaks and valleys. 
       FIG. 132(B)  is an image diagram of results of measurements of vibrational acceleration level of ear cartilage at each frequency, while a piezoelectric bimorph element like that described above has been placed into contact with ear cartilage. As will be clear from  FIG. 132(B) , ear cartilage exhibits large vibrational acceleration levels approaching those of the 1-2 kHz band, even in a band of 1 kHz or below, in which vibration of the piezoelectric bimorph element serving as the vibration source is relatively weak. This means that, in the frequency characteristics of ear cartilage, there is satisfactory transmission of vibration in a band of 1 kHz or below. Further, as will be clear from  FIG. 132(B) , despite the fact that vibration of the piezoelectric bimorph element serving as the vibration source is generally flat, ear cartilage exhibits a drop in vibrational acceleration level in a high frequency band starting from around 3 kHz. This means that, in the frequency characteristics of ear cartilage, vibration transmission efficiency drops in a high frequency band starting from around 3 kHz. 
     From examination of a graph showing an example of empirical data for the mobile telephone of the forty-sixth embodiment shown in  FIG. 79  on the basis of the above results, it is understood that the amplification of sound pressure, for example, in a 300 Hz-2500 Hz band, due to a transition from non-contact state shown by a solid line to a contact state shown by a single-dotted broken line, represents an aggregation of air-conducted sound in the non-contact state, plus air-conducted sound arriving via cartilage conduction through ear cartilage having the frequency characteristics shown in  FIG. 132(B) . The fact that the difference between the non-contact state shown by the solid line and the contact state shown by the single-dotted line is smaller in a band to the high-frequency end of 2500 Hz is consistent with the drop in the vibrational acceleration level in the high frequency band starting from around 3 kHz, which is observed in the frequency characteristics of ear cartilage shown in  FIG. 132(B) . 
     Further, in  FIG. 79 , in a frequency band from about 1 kHz to above 2 kHz, sound pressure in the non-contact state shown by the solid line and sound pressure in an unoccluded external auditory meatus state shown by the single-dotted line exhibit a tendency to increase or decrease in substantially identical directions, with respect to frequency change. In contrast to this, sound pressure in the non-contact state shown by the solid line and sound pressure in a occluded external auditory meatus state shown by the double-dotted line in  FIG. 79  exhibit a tendency to increase or decrease in opposite directions overall, with respect to frequency change. This means that the direct air-conducted sound component, which has strong effect from about 1 kHz to above 2 kHz, disappears upon closure of the entrance of the external auditory meatus, so that the effect of the frequency characteristics of ear cartilage, in which vibration transmission efficiency drops in the high frequency band, is expressed directly. As shown above, because the frequency characteristics of sound pressure in the unoccluded external auditory meatus state and the frequency characteristics of sound pressure in the occluded external auditory meatus state differ as a result of the frequency characteristics of ear cartilage shown in  FIG. 132(B) , there is a change in the quality of sound heard when the external auditory meatus is occluded. 
       FIG. 132(C)  further shows an image of equalization of the drive output to a piezoelectric bimorph element for the purpose of correcting the frequency characteristics of ear cartilage shown in  FIG. 132(B) . The solid line shows equalization performed in the unoccluded external auditory meatus state, and the dashed line equalization performed in the occluded external auditory meatus state. This equalization, as well as shifting between gain shown by the solid line and gain shown by the broken line, are performed by the cartilage conduction equalizer  8138  which is controlled by a controller  8139 . 
     As shown in  FIG. 132(C) , in the unoccluded external auditory meatus state, gain in the drive output is increased in the high frequency band from around 2500 Hz. Gain shift opposite in tendency from that in the frequency characteristics of ear cartilage shown in  FIG. 132(B)  with respect to frequency change is applied thereby, correcting the small difference between the non-contact state shown by the solid line and the contact state shown by the single-dotted line in  FIG. 79 . 
     In the high frequency band from around 2500 Hz, the effect of direct air conduction entering from the entrance of the external auditory meatus is large, whereas sound pressure produced by cartilage conduction is relatively small with respect thereto. Consequently, in cases in which this can be ignored, assuming the gain shown by the solid line in  FIG. 132(C)  to be flat, the eighty-six embodiment can be modified so as to perform equalization identical to equalization for ordinary direct air conduction. 
     In contrast to this, in the occluded external auditory meatus state shown by the dashed line in  FIG. 132(C) , in the high frequency band from around 2500 Hz, gain in the drive output is greatly elevated above that in the unoccluded external auditory meatus state shown by the solid line, as shown by an arrow. This corrects the frequency characteristics of sound pressure in the occluded external auditory meatus state, in which the effect of the frequency characteristics of ear cartilage are expressed directly, preventing changes in sound quality when the external auditory meatus is occluded. 
     As shown in  FIG. 132(B) , whereas ear cartilage exhibits a drop in vibrational acceleration level in a high frequency band starting from around 3 kHz, vibration per se is still possible, and therefore drop in sound pressure can be ameliorated by increasing the gain in the drive output in this frequency band. The extent to which to increase the gain is decided upon taking into consideration the fact that, in frequency band, the vibrational acceleration level of ear cartilage is low, and the efficiency with which sound pressure is increased despite increasing the drive output is poor. Moreover, because the sound signal sampling cycle in the telephone is 8 kHz and audio information above 4 kHz is absent from the outset, the fact that ear cartilage has frequency characteristics such that sound signals on the high-frequency band end are propagated with difficulty as shown in  FIG. 132(C)  does not pose a problem, and the principal components of the sound signal frequency band can be transmitted efficiently. By increasing the gain at the high-frequency end in a frequency band of 4 kHz and below in the aforedescribed manner, the sound quality of the sound signal can be improved. 
     The gain shift shown by the solid line and the dashed line in  FIG. 132(C)  may be performed automatically, for example, through detection by the pressure sensor  242  such as in the fifty-fourth embodiment. Alternatively, a microphone like the environment-noise microphone  4638  of the fiftieth embodiment could be furnished, switching automatically according to whether or not noise is greater than a predetermined level. In this case, on the assumption that, when noise is greater than a predetermined level, occlusion of the entrance of the external auditory meatus by the tragus or the like will have occurred with stronger pressing force against the ear cartilage naturally occurring as the user attempts to listen closely, the noise level at which automatic switching takes place may be set based on average values obtained through experimentation. 
     In preferred practice, the gain shifts shown by the solid line and the dashed line in  FIG. 132(C)  will be performed while employing a moving average value for pressure sensor output or environment-noise microphone output within a predetermined time interval, to avoid cumbersome shifting between the two. However, when the external auditory meatus becomes occluded, due to an earplug bone conduction effect (herein, the phenomenon designated thusly is the same as that known as the “external auditory meatus occlusion effect”), sound becomes louder, and there tends to be a noticeable change in sound quality; therefore, gain shifting may incorporate an element of hysteresis whereby, through a configuration in which shifting takes place relatively slowly, for example by performing gain shifts in a direction from the solid line to the dashed line in  FIG. 132(C)  rapidly in response to a detected increase in pressing force or environment noise, but holding back from performing gain shifts in a direction towards the solid line from the dashed line associated with softer sound, until change in a decreasing direction has been detected a predetermined number of times. 
       FIG. 133  is a flowchart showing functions of a controller  8139  the eighty-sixth embodiment of  FIG. 131 . The flow of  FIG. 133  primarily describes control of the cartilage conduction equalizer  8138 , and therefore operations centered on related functions have been extracted for illustration, and there are other operations of the controller  8139 , such as typical functions of mobile telephones and like, which are not represented in the flow of  FIG. 133 . While it is possible for the controller  8139  to concomitantly accomplish functions shown in various other embodiments, to avoid complexity, illustrations and descriptions of these functions as well have been omitted in  FIG. 133 . 
     The flow of  FIG. 133  starts when the main power source of the mobile telephone  8101  is turned on, and in Step S 452 , initial startup and a function check of each unit are performed, as well as initiating screen display on a large-screen display unit  8205  of the mobile telephone  8101 . Next, in Step S 454 , the functions of the cartilage conduction unit (the cartilage conduction vibration unit  228 ) and the outgoing-talk unit (the outgoing-talk-processing unit  222 ) of the mobile telephone  8101  are turned off, and the routine advances to Step S 456 . 
     In Step S 456 , a check is performed to determine whether an earphone or the like has been inserted in the external earphone jack  8146 . Then, in the event that insertion into the external earphone jack  8146  is not detected, the routine proceeds to Step S 458 , in which a check is performed to determine whether short-range communication has been established with a mobile telephone accessory device, such as a headset, by a short-range communication unit  8147 . In the event this is not the case either, the routine proceeds to Step S 460 , and a check is performed to determine whether the current state is one in which another caller&#39;s answer to a telephone call request, or a call through mobile radio waves based on an incoming call, is in progress. When the current state is the talk state, the routine proceeds to Step S 462 , the cartilage conduction unit (the cartilage conduction vibration unit  228 ) and the outgoing-talk unit (the outgoing-talk-processing unit  222 ) are turned on, and routine proceeds to Step S 464 . 
     In Step S 464 , a check is performed to determine whether the current state is one an earplug bone conduction effect has occurred due to occlusion of entrance of the external auditory meatus, and in the event this is not the case, the routine advances to Step S 466 , then proceeds to Step S 468  without applying a signal in which the waveform of the user&#39;s own voice is inverted. The process of application/non-application of a waveform-inverted signal of the user&#39;s own voice has been described in Step S 52  to Step S 56  in the flow of  FIG. 10 , and therefore the details are omitted here. In Step S 468 , the equalization indicated by the solid line in  FIG. 132(C)  is established, and the routine advances to Step S 470 . The equalization performed in Step S 468  involves increasing the gain in drive output in the high-frequency band from around 2500 Hz, the equalization being premised on significant participation by direct-air conduction entering from the entrance of the external auditory meatus. As a modified embodiment, a configuration like that described above, in which equalization in Step S 468  and equalization for the purpose of ordinary direct air conduction are the same, would be acceptable. 
     On the other hand, when occurrence of an earplug bone conduction effect due to occlusion of the entrance of the external auditory meatus has been detected in Step S 464 , the routine advances to Step S 470 , applying a waveform-inverted signal of the user&#39;s own voice, as well as establishing equalization involving increased gain in drive output in the high-frequency band from around 2500 Hz in Step S 472 , and advances to Step S 470 . 
     In Step S 470 , a check is performed to determine whether the call has ended, and in the event this is not the case, returns to Step S 464 , repeating Step S 464  to Step S 472  for as long as the call has not ended. In so doing, equalization can be shifted between the solid line and the dash line of  FIG. 132(C)  in response to changes in settings or conditions during a call. On the other hand, in the event that the call is detected to have ended in Step S 470 , the routine advances to Step S 474 , the functions of the cartilage conduction unit (the cartilage conduction vibration unit  228 ) and the outgoing-talk unit (the outgoing-talk-processing unit  212 ) of the mobile telephone  8101  are turned off, and the routine proceeds to Step S 476 . When the talk state is not detected in Step S 460 , the routine advances directly to Step S 476 . 
     In contrast to this, when insertion into the external earphone jack  8146  has been detected in Step S 456 , or establishment of short-range communication with a mobile telephone accessory device has been detected in Step S 458 , the routine advances to Step S 478 . In Step S 478 , a check is performed in the same manner as in Step S 460 , to ascertain whether a call through mobile radio waves is in progress. In the event that the device is not currently in the talk state, the routine proceeds to Step S 480 , equalization for the purpose of normal air conduction is established, and the routine advances to Step S 482 . 
     In Step S 482 , a check is performed to determine whether the call has ended, and in the event this is not the case, returns to Step S 480 , repeating Step S 480  to Step S 482  for as long as the call has not ended. On the other hand, in the event that the call is detected to have ended in Step S 482 , the routine advances to Step S 476 . When the talk state is not detected in Step S 478 , the routine advances directly to Step S 476 . 
     In Step S 476 , a check is performed to determine whether or not the main power source of the mobile telephone  8101  has been turned off, and in the event the main power source is not off, the routine returns to Step S 456 , and thereafter repeats Step S 456  to Step S 482  for as long as turning off of the main power source is not detected in Step S 476 . In contrast to this, once it is detected in Step S 456  that the main power source has turned off, the flow terminates. 
       FIG. 134  is perspective views showing a modification example of the eighty-sixth embodiment shown in  FIG. 131 . For the description of  FIG. 134 , borrowing from  FIG. 110(A)  and  FIG. 100(B)  of the seventy-third embodiment which is similar in external appearance, common portions have been assigned the same reference numerals, and descriptions have been omitted.  FIG. 134(A)  is a front perspective view of the mobile telephone  8101 , and  FIG. 134(B)  is a back perspective view of the mobile telephone  8101 . In  FIG. 134 , unlike in the seventy-third embodiment, the in-camera  8117  is situated in an upper part of the mobile telephone  8101 . 
     In the modification example of the eighty-sixth embodiment shown in  FIG. 134 , the back surface of the mobile telephone  8101  is furnished with a pressing force sensing unit  8142  for detecting obstruction of the external auditory meatus, as shown in  FIG. 134(B) . This pressing force sensing unit  8142  is positioned at a location of spontaneous touching by the index finger of the hand when the mobile telephone  8101  is held against the ear by the user. When the user presses the mobile telephone  8101  forcefully against the ear to the extent that the external auditory meatus becomes obstructed, the intensity with which the index finger supporting this action presses against the pressing force sensing unit  8142  increases. Obstruction of the external auditory meatus is thereby detected on the basis of the output of the pressing force sensing unit  8142 . 
     In order to avoid unintentional operation, as shown in  FIG. 134(A) , the upper part of the mobile telephone  8101  is furnished with a pair of infrared light-emitting units  8119 ,  8120  constituting proximity sensors for detecting that the mobile telephone  8101  is contacting the ear for the purpose of a call, and a common infrared light proximity sensor  8121  for picking up reflected infrared light from the ear. In so doing, the pressing force sensing unit  8142  is functional only when the mobile telephone  8101  is contacting the ear, so that in the event that the user applies force to the pressing force sensing unit  8142  while, for example, looking at the display screen  6905  or the like, the mobile telephone  8101  will not react. 
     The pressing force sensing unit  8142  is furnished near a central portion thereof with a pressure-sensitive protrusion  8142   a , not only as a means for detecting when the intensity of spontaneous pressing by the index finger exceeds as predetermined level, but also to enable intentional pressing operations thereof. In this way, the pressing force sensing unit  8142  can also function as a manual switch for equalization switching. 
     Eighty-Seventh Embodiment 
       FIG. 135  is a block diagram relating to an eighty-seventh embodiment according to an aspect of the present invention, configured as a typical mobile telephone  1601  and a headset  8281  capable of short-range communication therewith.  FIG. 135  has much in common with the seventeenth embodiment of  FIG. 29 , and therefore the same reference numerals are assigned to the common portions, omitting descriptions unless necessary. 
     The eighty-seventh embodiment of  FIG. 135  differs from the seventeenth embodiment of  FIG. 29  in that the headset  8281  has a cartilage conduction equalizer  8238  controlled by a controller  8239 . The cartilage conduction equalizer  8238  has functions resembling those of the cartilage conduction equalizer  8138  of the eighty-sixth embodiment of  FIG. 131 , and adopts a piezoelectric bimorph element having frequency characteristics in common with that shown in  FIG. 132(A) , as a vibration source for a cartilage conduction vibration unit  1626 . The device is configured to perform the equalization shown in  FIG. 132(C) , in order to handle the frequency characteristics of ear cartilage shown in  FIG. 132(B) . Switching between the solid line and the dashed line of  FIG. 132(C)  is performed on the basis of detection by a bending detection unit  1588 . 
     In the eighty-seventh embodiment of  FIG. 135 , the sound signal on which equalization on the premise of normal air conduction has been performed is transmitted to the headset  8281  by the mobile telephone  1601  from the short-range communication unit  1446 . The headset  8281  is configured to have the cartilage conduction vibration unit  1626 , and therefore the equalization shown in  FIG. 132(C)  is performed by the cartilage conduction equalizer  8238 , on the basis of the received sound signal. 
     Returning to the eighty-sixth embodiment of  FIG. 86  to supplement the description, when insertion of the external earphone jack  8146  has been detected in Step S 456  of the flowchart of  FIG. 133 , or when establishment of short-range communication with a mobile telephone accessory device has been detected in Step S 458 , normal air equalization is performed. The reason for doing so is that the device is assumed to be compatible with normal air type earphones and headsets or, in the case of a cartilage conduction type headset, to be paired with a headset which is itself provided with the cartilage conduction equalizer  8238 , as in the eighty-seventh embodiment of  FIG. 135 . 
     Eighty-Eighth Embodiment 
       FIG. 136  is a perspective view and cross sectional views relating to an eighty-eighth embodiment according to an aspect of the present invention, configured as a mobile telephone  8201 . A feature of the eighty-eighth embodiment resides in the structure of the cartilage conduction unit, and therefore the description shall center thereon; configurations shown in the other embodiments can be adopted, as appropriate, for the other portions, so illustrations and descriptions of these are omitted.  FIG. 136(A)  is a front perspective view of the eighty-eighth embodiment. The configuration of chassis of the mobile telephone  8201  is one in which a front panel  8201   a  of plastic or the like and a back panel  8201   b  of plastic or the like sandwich a metal frame. The metal frame is divided into an upper frame  8227 , a right frame  8201   c , a lower frame  8201   d , and a left frame  8201   e  (not visible in  FIG. 136(A) ), with elastic bodies  8201   f  respectively interposed therebetween. The front panel  8201   a  is furnished with a window for a large-screen display unit  8205 , and with a window for a microphone  8223  and a window for an in-camera  8017 . 
     At an inside center part of the upper frame  8227  an electromagnetic vibrator  8225  serving as a cartilage conduction vibration source is anchored in such a way as to vibrate in a direction perpendicular to the front panel  8201   a . The electromagnetic vibrator  8225  has substantially no contact with parts other than the upper frame  8227 , so vibration of the electromagnetic vibrator  8225  is propagated only to the upper frame  8227 . Vibration of the electromagnetic vibrator  8225  propagated to the center part of the upper frame  8227  is transmitted to a right side corner part  8224  and a left side corner part  8226  of the electromagnetic vibrator  8225 , which serve as cartilage conduction units. In this way, according to the eighty-eighth embodiment, the metal upper frame  8227  is concomitantly employed for cartilage conduction, and in the same manner as in other embodiments, upper corner parts at the left and right of the chassis of the mobile telephone  8201  (the right side corner part  8224  and the left side corner part  8226 ) function as cartilage conduction units. However, in the eighty-eighth embodiment, in the same manner as in the fourth embodiment of  FIG. 7 , the upper frame  8227  does not vibrate solely at the right side corner part  8224  at the right edge and the left side corner part  8226  at the left edge, but rather vibrates in its entirety, whereby audio information can be transmitted regardless of which part of the inside upper edge side of the mobile telephone  8201  is placed against the ear cartilage. This will be discussed in detail below. 
     The configuration of the eighty-eighth embodiment is properly described as one whereby, when the inside upper edge of the mobile telephone  8201  is placed against the ear cartilage, an area proximate to the upper edge of the front panel  8201   a  actually contacts the ear cartilage. That is, vibration of the upper frame  8227  (including the right side corner part  8224  and the left side corner part  8226 ) is propagated to an area proximate to the upper edge part of the front panel  8201   a , from whence it is transmitted to the ear cartilage. Moreover, as vibration of the upper frame  8227  entails vibration of an area proximate to the upper edge part of the front panel  8201   a  over a relatively large surface area, required air conduction is generated from the upper edge part of the front panel  8201   a  as well. The eighty-eighth embodiment can be said to share this feature in common with the tenth embodiment of  FIG. 19 . Specifically, the electromagnetic vibrator  8225  serves as the cartilage conduction vibration source, and concomitantly as a drive source for the incoming-call unit, for generating sound waves which are propagated to the eardrum through ordinary air conduction. Consequently, in the same manner as in other embodiments, it is possible to make calls in a manner benefiting from the advantages of cartilage conduction, in a style in which an upper corner part of the mobile telephone  8201  placed against the ear cartilage, such as the tragus; while at the same time it is possible to make calls in the ordinary style, i.e., with the vicinity of an upper edge center part of the mobile telephone  8201  placed against the ear. Further, because the upper edge part of the front panel  8201   a  vibrates over a relatively wide surface area in the aforedescribed manner, air-conducted sound can be generated at the required level from an ordinary mobile telephone, even one not furnished with an incoming-call unit that relies on air conduction, such as a speaker. The details of this will be discussed below. 
     Moreover, due to being isolated from the right frame  8201   c  and the left frame  8201   e  by the elastic bodies  8201   f , transmission of vibration the upper frame  8227  to the lower part of the chassis is suppressed, so in the same manner as in other embodiments, the vibration energy of the electromagnetic vibrator  8225  serving as the cartilage conduction vibration source can be efficiently contained within the upper frame  8227 . Vibration of the upper frame  8227 , by virtue of the contact thereof with the front panel  8201   a  in the aforedescribed manner, is manifested as vibration over a relatively wide surface area in the vicinity of an upper edge thereof. However, vibration of a lower part of the front panel  8201   a  is suppressed by the right frame  8201   c , the lower frame  8201   d , and the left frame  8201   e  which, due to the interposed elastic bodies  8201   f , have low vibration transmission, whereby vibration of the front panel  8201   a  is reduced in the course of traveling downward (through a portion including the large-screen display unit  8205 ), where sound generation is unwanted. 
     The upper frame  8227  also concomitantly performs the function of the antenna  5345  of the telephone function unit shown in the fifty-seventh embodiment of  FIG. 87 . In specific terms, the antenna  5345  includes a transmission antenna and a reception antenna; in the eighty-eighth embodiment of  FIG. 136 , the upper frame  8227  which serves as a cartilage conduction unit is employed concomitantly as an antenna for reception as well. 
     Further, an external earphone jack  8246  like that in the eighty-fourth embodiment of  FIG. 127  is anchored to the upper frame  8227 . In so doing, the upper frame  8227  can be furnished with the external earphone jack  8246  by means of a structure of utmost simplicity. In the aforedescribed structure, when the upper frame  8227  vibrates, the external earphone jack  8246  will vibrate as well; however, when an external earphone plug has been inserted into the external earphone jack  8246 , this is detected, whereby vibration of the upper frame  8227  is halted. Consequently, in a state in which cartilage conduction is propagated to ear cartilage, vibration of the external earphone jack  8246  does not pose a problem because no external earphone plug is inserted, whereas when an external earphone plug is inserted, vibration of the upper frame  8227  is halted, so there is no problem in this case either. Likewise, when the upper frame  8227  vibrates, this vibration is propagated to the in-camera  8017  as well via internal structures and the front panel  8201   a  or the like, but when the device is in videoconferencing mode using the in-camera  8017 , vibration of the upper frame  8227  is halted, and therefore there is no problem in this case either. 
     Further, a power switch  8209  is situated on the upper frame  8227 . To make it possible to slide the power switch  8209  up and down with respect to the upper frame  8227 , it is positioned within a window in the upper frame  8227 , leaving a small gap, so as to not contact the upper frame  8227 . In so doing, when the upper frame  8227  vibrates, the vibration thereof will not be propagated to the power switch  8209 , nor will the inside edge of the window of the vibrating upper frame  8227  strike or chatter against the power switch  8209 . 
       FIG. 136(B)  is a B 1 -B 1  cross sectional view of  FIG. 136(A) , in which identical portions are assigned the same reference numerals, omitting discussion thereof unless necessary. As will be clear from  FIG. 136(B) , the electromagnetic vibrator  8225  is anchored to an inside center part of the upper frame  8227 , and connected to a driver circuit terminal by a flexible connector cable  8225   a . Moreover, as will be clear from  FIG. 136(B) , the electromagnetic vibrator  8225  has substantially no contact with parts other than the upper frame  8227 . Further, because the elastic bodies  8201   f  have been respectively interposed between the upper frame  8227 , the right frame  8201   c , and the left frame  8201   e , transmission of vibration of the upper frame  8227  to the lower part of the chassis is suppressed. In this way, the upper frame  8227  may be employed concomitantly in suitable fashion as a cartilage conduction unit. 
     As will be clear from  FIG. 136(B) , the upper frame  8227  is connected to an antenna terminal of the telephone function unit by a flexible connector cable  8227   a , and thereby employed concomitantly as a reception antenna. Moreover, the external earphone jack  8246  is anchored to the upper frame  8227 , and connected to an external output circuit terminal by a flexible connector cable  8246   a . The upper frame  8227  is moreover furnished with a window for placement of the power switch  8209 , making it possible for the power switch  8209 , which has been furnished to a waterproof power switch unit  8209   a , to move up and down without contacting the upper frame  8227  due to a small gap relative to the inner edge of the window. The waterproof power switch unit  8209   a  is supported by an internal structure  8209   b , and connected to a controller terminal by a wire  8209   c . A waterproof packing is sandwiched between the inside edge of the window of the upper frame  8227  and the waterproof power switch unit  8209   a , making it possible for the upper frame  8227  to vibrate independently of the waterproof power switch unit  8209   a , as well as to prevent water from infiltrating between the two. 
       FIG. 136(C)  is a top view of  FIG. 136(A) , in which identical portions are assigned the same reference numerals, omitting discussion thereof unless necessary. As will be clear from  FIG. 136(C) , an upper edge of the front panel  8201   a  and an upper edge of the back panel  8201   b  are configured to sandwich the upper frame  8227 . The external earphone jack  8246  and the power switch  8209  are exposed on the upper frame  8227 . 
       FIG. 136(D)  is the B 2 -B 2  cross sectional view shown in  FIG. 136(A)  to  FIG. 136(C) , in which identical portions are assigned the same reference numerals, omitting discussion thereof unless necessary. As will be clear from  FIG. 136(D) , the front panel  8201   a  and the back panel  8201   b  are configured to sandwich the upper frame  8227 . The electromagnetic vibrator  8225  is anchored to the inside center part of the upper frame  8227 . As will be clear from  FIG. 136(D) , the electromagnetic vibrator  8225  has substantially no contact with any parts other than the upper frame  8227 . 
       FIG. 136(E)  is the B 3 -B 3  cross sectional view shown in  FIG. 136(B) , in which identical portions are assigned the same reference numerals, omitting discussion thereof unless necessary. As will be clear from  FIG. 136(E) , the front panel  8201   a  and the back panel  8201   b  are configured to sandwich a right corner part  8224  of an edge part of the upper frame  8227 . As will be clear from  FIG. 136(E) , an elastic body  8201   f  is interposed between the right corner part  8224  of the edge part of the upper frame  8227  and the right frame  8201   c , suppressing transmission of vibration of the upper frame  8227  (including the right corner part  8224 ) to the lower part of the chassis (including the right frame  8201   c ). 
       FIG. 137  is side views of the mobile telephone  8201 , describing a talk state in the eighty-eighth embodiment of  FIG. 136 .  FIG. 137(A)  is a view substantially similar to  FIG. 2(A)  shown in the first embodiment, and shows the mobile telephone  8201  placed against the right ear  28  while held in the right hand. Like  FIG. 2 ,  FIG. 137(A)  is a view of the face seen from the right side, in which the back surface side (the rear side in  FIG. 136(A) ) of the mobile telephone  8201  is visible. As in  FIG. 2 , the mobile telephone  8201  is shown by single-dotted lines in order to depict the relationship of the mobile telephone  8201  and the right ear  28 . 
     In the mobile telephone  8201  of the eighty-eighth embodiment, the entire upper frame  8227  vibrates, and in the talk state of  FIG. 137(A) , as in  FIG. 2(A) , the right corner part  8224  contacts the left ear  28  in proximity to the tragus, whereby the advantages of cartilage conduction during a call are realized in the same manner as in other embodiments. 
     In contrast to this,  FIG. 137(B)  shows a call being made in the ordinary style, with an area proximate to the upper edge center part of the mobile telephone  8201  pressed against the ear. At this time as well, because a relatively long area  8227   b  in a center portion of the upper frame  8227  contacts the cartilage surrounding the entrance of the external auditory meatus, talk through the agency of cartilage conduction is possible. Further, as described previously, because the upper edge part of the mobile telephone  8201  vibrates through a relatively wide surface area, air-conducted sound can be generated at the required level from an ordinary mobile telephone. Consequently, in the talk state as in  FIG. 137(B) , talk is possible through the agency of cartilage conduction from the center portion of the upper frame  8227 , and through the agency of air-conducted sound entering through the entrance of the external auditory meatus. An air-conducted sound component entering through the entrance of the external auditory meatus is present in the talk state shown in  FIG. 137(A)  as well, but the proportion thereof is greater in  FIG. 137(B) . 
     The mobile telephone  8201  of the eighty-eighth embodiment shares in common with other embodiments the fact that the advantages of cartilage conduction can be utilized to the maximum in the call style shown in  FIG. 137(A) . However, with the mobile telephone  8201  of the eighty-eighth embodiment, when used as shown in  FIG. 137(B) , whether out of user preference or a misunderstanding of how the device should be used, the device can nevertheless be used without any problem as an ordinary mobile telephone, and air-conducted sound can be generated at the required level, even when the device is not furnished with an incoming-call unit that relies on air conduction, such as a speaker, and as such is a commercially viable configuration meeting specifications for an ordinary mobile telephone. 
     While  FIG. 137  describes the case of use with the right ear, in the case of using the mobile telephone  8201  with the left ear, in exactly the same manner, use in a style with the left corner part  8226  placed in contact with an area proximate to the tragus of the left ear, as well as talk in the ordinary style with the upper center part of the mobile telephone  8201  pressed against the ear, are possible. 
       FIG. 138  is cross sectional views showing modification examples of the eighty-eighth embodiment of  FIG. 136 . The modification examples relate to configurations whereby vibration energy may be further concentrated in the proximity to the upper edge of the front panel  8201   a  which actually contacts the ear cartilage when the inside upper edge of the mobile telephone  8201  is pressed against the ear cartilage.  FIG. 138(A)  is exactly the same as  FIG. 136(E) , and is illustrated again for reference. Consequently,  FIG. 138(A)  is the B 3 -B 3  cross section in  FIG. 136(B) , in which the upper frame  8227  and the right corner part  8224  thereof are visible in cross section. The modification examples are configured such that upper edge-proximate portions of the front panel  8201   a  and the back panel  8201   b  are thinner than other portions, thereby modifying the width and shape of the right corner part  8224 , but in the modification examples, the cross section proximate to the upper edges of the front panel  8201   a  and the back panel  8201   b , and the width of the upper surface of the upper frame  8227 , in both the left corner part  8226  and the center part are identical to those in the right corner part  8224 . 
       FIG. 138(B)  is configured such that an upper edge-proximate portion  8201   g  of the front panel  8201   a  is thinner than other portions, and likewise for the back panel  8021   b  as well, an upper edge-proximate portion  8201   h  thereof is thinner than other portions. In correspondence therewith, the width of the right corner part  8224   a  of the upper frame  8227  is greater than that of a right frame  8201   i . In association with this, the cross section of an elastic body  8201   j  is trapezoidal so as to connect the two. By configuring the upper edge-proximate portion  8201   g  of the front panel and the upper edge-proximate portion  8201   h  of the back panel  8201   b , which contact the vibrating upper frame  8227  in this way, to respectively be thinner than other portions, these upper edge-proximate portions vibrate more easily, and better propagate vibration of the upper frame  8227 . The lower parts of the front panel  8201   a  and the back panel  8201   b  are more resistant to vibration, due to the difference in thickness. 
       FIG. 138(C)  is configured such that the inside of an upper edge-proximate portion  8201   k  of the front panel  8201   a  has a tapered shape becoming thinner towards the top, and likewise in the back panel  8021   b  as well, the inside of an upper edge-proximate portion  8201   m  thereof has a tapered shape becoming thinner towards the top. In association with this, a right corner part  8224   b  of the upper frame  8227  is trapezoidal. With this configuration as well, the upper edge-proximate portion  8201   k  of the front panel  8201   a  and the upper edge-proximate portion  8201   m  of the back panel  8201   b  which contact the vibrating upper frame  8227  vibrate more easily, and better propagate vibration of the upper frame  8227 . The lower parts of the front panel  8201   a  and the back panel  8201   b  are more resistant to vibration, due to their increasing thickness in the downward direction. 
       FIG. 138(D)  is configured such that the outside of an upper edge-proximate portion  8201   n  of the front panel  8201   a  has a tapered shape becoming thinner towards the top, and likewise in the back panel  8021   b  as well, the outside of an upper edge-proximate portion  8201   p  thereof has a tapered shape becoming thinner towards the top. With this configuration as well, the upper edge-proximate portion  8201   n  of the front panel  8201   a  and the upper edge-proximate portion  8201   p  of the back panel  8201   b  which contact the vibrating upper frame vibrate more easily, and better propagate vibration of the upper frame  8227 . The lower parts of the front panel  8201   a  and the back panel  8201   b  are more resistant to vibration, due to their increasing thickness in the downward direction. 
     The various features of the embodiments described above are not limited to implementation in the aforedescribed embodiments, and may be implemented in other embodiments as well, provided that the advantages thereof can be enjoyed by doing so. For example, in the eighty-eighth embodiment, the cartilage conduction vibration source was configured as an electromagnetic vibrator. An electromagnetic vibrator is suited to in layouts which members are closely packed on the upper part of a mobile telephone. However, the cartilage conduction vibration source adopted in the eighty-eighth embodiment is not limited to one of electromagnetic type, and a piezoelectric bimorph element like those shown in other embodiments, for example, would be acceptable. 
     Eighty-Ninth Embodiment 
       FIG. 139  is a system configuration diagram of an eighty-ninth embodiment of an aspect according to the present invention. The eighty-ninth embodiment is configured as a headset for use as an outgoing-talk/incoming-talk unit for a mobile telephone, which, together with an ordinary mobile telephone  1401 , makes up a mobile telephone system. In the eighty-ninth embodiment, as in the twenty-fourth embodiment of  FIG. 37 , a cartilage conduction unit is situated at a location touching an anterior region at the outside  1828  of the cartilage of the base of the ear  28  (the mastoid process side of the auricle attachment region), and a headset  8381  incorporating the cartilage conduction unit is capable of communicating with the ordinary mobile telephone  1401  through a short-range communication unit  8387  such as a Bluetooth™ device or the like. Consequently, portions in common with  FIG. 37  have been assigned common reference numbers, and descriptions thereof are omitted. Also, reference numbers have not been assigned to the mobile telephone  1401  portions. 
       FIG. 139(A)  is a side view showing a relationship of the headset  8381  and the ear  28  in the eighty-ninth embodiment. As will be clear from  FIG. 139(A) , the headset  8381  of the eighty-ninth embodiment comprises an ear-hook unit  8382  incorporating the cartilage conduction unit, and headset body  8384 , the two being connected by a detachable cable  8381   a . The headset body  8384  has a microphone  8323  or the like, and clips to a breast pocket or the like. In  FIG. 139(A) , to avoid complexity while providing a clear overview of the interrelationships, the ear  28  is depicted by solid lines, and the ear-hook unit  8382  for hooking onto the outside  1828  of the base thereof is depicted by imaginary lines, with the internal configuration omitted. 
     In contrast to this,  FIG. 139(B)  is a system configuration diagram from which illustration of the ear, except for the entrance of the external auditory meatus (the earhole)  232 , has been omitted, and which shows the details of the headset  8381  of the eighty-ninth embodiment, together with the mobile telephone  1401 . Portions identical to those in  FIG. 139(A)  have been assigned the same reference numerals. The ear-hook unit  8382 , shown in cross section in  FIG. 139(B) , is constituted of elastic material of acoustic impedance approximating that of ear cartilage. As will be clear from  FIG. 139(B) , the inner edge of the ear-hook unit  8382  constitutes a contact part for linear contact hooked around the base of the ear  28  along the outside  1828  thereof. A holding part  8325   a  made of hard material is furnished in proximity to a portion closest to the external auditory meatus entrance (the earhole)  232 , at the outside  1828  of the cartilage of the base of the ear  28 , with one end of a piezoelectric bimorph element  8325  being supported in cantilever fashion by this holding part  8325   a.    
     As will be clear from  FIG. 139(B) , the piezoelectric bimorph element  8325  does not contact the interior of the ear-hook unit  8382  in any portion thereof other than the support part  8325   a , whereby the other end side (connection terminal side) of the piezoelectric bimorph element  8325  vibrates freely, the counteraction thereof being transmitted as vibration to the support part  8325   a . Vibration of the support part  8325   a  is then transmitted from the inner edge of the ear-hook unit  8382  to the outside  1828  of the base of ear  28  in linear contact therewith, this vibration producing air-conducted sound from the external auditory meatus inner wall through the agency of the cartilage surrounding the external auditory meatus opening, which sound is transmitted to the eardrum. The outside  1828  of the cartilage of the base of ear is close to the external auditory meatus entrance  232  to the inside thereof, providing suitable conditions for producing air conduction in the external auditory meatus interior, from the cartilage surrounding the external auditory meatus opening. 
     Meanwhile, the headset body  8384  has the short-range communication unit  8387  such as a Bluetooth™ device or the like, which is capable of communicating with the mobile telephone  1401 . A sound signal received by radio waves  1285  through the short-range communication unit  8387  from the mobile telephone  1401  is presented from a sound unit  8336  to an amplifier  8340  via an acoustic processing circuit  8338 . The amp  8340  drives the piezoelectric bimorph element  8325  from a connector  8346  via a cable  8381   a . A sound signal picked up by the microphone  8323  is transmitted to the mobile telephone  1401  from the short-range communication unit  8387  by the radio waves  1285  via the sound unit  8336 . A controller  8339  controls the short-range communication unit  8387 , the acoustic processing circuit  8338 , and the sound unit  8336 , as well as transmitting operation signals from an operating unit  8309  to the mobile telephone  1401  from the short-range communication unit  8387 . A power supply unit  8348  including a rechargeable cell supplies power to the entire headset  8381 . 
     In the preceding eighty-ninth embodiment, the piezoelectric bimorph element  8325  for cartilage conduction is situated in the ear-hook unit  8382  while the microphone  8323  is situated in the headset body  8384 , the two being separated from one another and connected only by the flexible cable  8381   a , so that the microphone  8323  is unaffected by vibration of the piezoelectric bimorph element  8325 . Moreover, in the eighty-ninth embodiment, vibration for the purpose of cartilage conduction is transmitted from the rear side of the ear  28 , and therefore the external auditory meatus entrance (the earhole)  232  is completely free, so entry of sounds, such as a car horn, into the ear in an emergency situation is unimpeded, nor is there the discomfort associated with inserting an earphone or the like into the external auditory meatus entrance (the earhole)  232 . An external auditory meatus occluding effect can readily be obtained by covering the ear  28  with the hand in order to enhance the cartilage conduction effect, whereby increased volume and blockage of outside noise can be achieved. 
     In  FIG. 139 , for simplicity, only one ear-hook unit  8382 , that for the right ear, is illustrated; however, it would be possible for an ear-hook unit of similar configuration for the left ear to be connected in common to the headset body  8384 , and the respective ear-hook units hooked on both ears to afford a stereo reception unit. In so doing, ordinary calls are easier to hear, and the configuration is one suited to enjoyment of music as well. 
     Ninetieth Embodiment 
       FIG. 140  is a system configuration diagram of a ninetieth embodiment of an aspect according to the present invention. The ninetieth embodiment is likewise configured as a headset for use as an outgoing-talk/incoming-talk unit for a mobile telephone, which, together with the ordinary mobile telephone  1401 , makes up a mobile telephone system. In the ninetieth embodiment, as in the eighty-ninth embodiment of  FIG. 139 , a cartilage conduction unit is situated at a location touching an anterior region at the outside  1828  of the cartilage of the base of the ear  28 , and a headset  8481  incorporating the cartilage conduction unit is capable of communicating with the ordinary mobile telephone  1401  through a short-range communication unit  8487  such as a Bluetooth™ device or the like. Consequently, portions in common with  FIG. 139  have been assigned common reference numbers, and descriptions thereof are omitted. 
       FIG. 140(A)  is a side view showing a relationship of the headset  8481  and the ear  28  in the ninetieth embodiment. As will be clear from  FIG. 140(A) , a point of difference between the ninetieth embodiment and the eighty-ninth embodiment of  FIG. 139  is that the headset  8481  is configured as an integrated unit. That is, in the ninetieth embodiment, the microphone and other configurations are situated within the headset  8481 . In  FIG. 140(A) , adopting the same convention as in the eighty-ninth embodiment, the ear  28  is shown by solid lines, and the ear-hook unit  8482  for hooking onto the outside  1828  of the base thereof is depicted by imaginary lines, with the internal configuration omitted. 
     In contrast to this,  FIG. 140(B) , like  FIG. 139(B) , is a system configuration diagram from which illustration of the ear  28 , except for the entrance of the external auditory meatus (the earhole)  232 , has been omitted, and which shows the details of the headset  8481  of the ninetieth embodiment, together with the mobile telephone  1401 . Portions identical to those in  FIG. 140(A)  have been assigned the same reference numerals. The headset  8481 , shown in cross section in  FIG. 140(B) , has the ear-hook unit  8482  constituted of elastic material, the inner edge of which constitutes a contact part for linear contact while hooked around the base of the ear  28  along the outside  1828  thereof. Moreover, as in the eighty-ninth embodiment, a piezoelectric bimorph element  8325  is supported at one end in cantilever fashion by a holding part  8482   a  situated closest to the external auditory meatus entrance (the earhole)  232 , at the outside  1828  of the cartilage of the base of the ear  28 . 
     As will be clear from  FIG. 140(B) , in the ninetieth embodiment as well, the piezoelectric bimorph element  8425  does not contact the interior of the ear-hook unit  8482  in any portion thereof other than the support part  8482   a , whereby the other end side (connection terminal side) of the piezoelectric bimorph element  8425  vibrates freely, the counteraction thereof being transmitted as vibration to the support part  8482   a . Vibration of the support part  8482   a  is then transmitted in the same manner as in the eighty-ninth embodiment, from the inner edge of the ear-hook unit  8482  to the outside  1828  of the base of ear  28  in linear contact therewith, this vibration producing air-conducted sound from the external auditory meatus inner wall through the agency of the cartilage surrounding the external auditory meatus opening, which sound is transmitted to the eardrum. 
     An upper part of the ear-hook unit  8482  is continuous with an anterior part  8484  comprising the same hard material, and situated across a gap  8481   b  therefrom. The anterior part  8484  is furnished with the short-range communication unit  8487  such as a Bluetooth™ device or the like, capable of communicating with the mobile telephone  1401 . A sound signal received by the short-range communication unit  8487  by radio waves  1285  from the mobile telephone  1401  is presented from a sound unit  8436  to an amplifier  8440  via an acoustic processing circuit  8438 , in an arrangement identical to the eighty-ninth embodiment. The amp  8440  drives the piezoelectric bimorph element  8425  through a cable  8481   a  passing from the anterior part  8484  and through a connecting part to the ear-hook unit  8482 . While omitted from the illustration in  FIG. 140(B) , the ninetieth embodiment also has a controller and an operating unit analogous to those in the eighty-ninth embodiment. 
     The microphone  8423 , which is furnished to a distal end of an extension part  8481   c  a considerable distance below a portion connecting to the ear-hook unit  8482 , is connected to the sound unit  8486 . In so doing, sound signals picked up by the microphone  8423  are transmitted to the mobile telephone  1401  by the radio waves  1285 , from the short-range communication unit  8487  via the sound unit  8436 . 
     A rechargeable cell  8485  of a power supply unit for supplying power to the headset  8481  as a whole is situated intervening between the ear-hook unit  8482  and the extension part  8481   c  within the anterior part  8484 . According to the ninetieth embodiment, the headset  8481  is of integrated configuration, and therefore vibration of the piezoelectric bimorph element  8425  is propagated to the anterior part  8484  from the ear-hook unit  8482 . However, due to the cell  8485  being situated in the aforedescribed manner, vibration of the anterior part  8484  is suppressed midway by weight of the cell  8485 , and the vibration component transmitted to the extension part  8481   c  is small. Consequently, the effects of vibration of the piezoelectric bimorph element  8425  on the microphone  8423  are minimal. 
     Ninety-First Embodiment 
       FIG. 141  is cross sectional views and a block diagram relating to a ninety-first embodiment according to an aspect of the present invention, configured as a stereo headphone system  8581 . The ninety-first embodiment is based on the sixty-third embodiment of  FIG. 95 , and therefore descriptions of elements common to both are omitted to the greatest possible extent, focusing the description on the elements being added.  FIG. 141(A)  shows a cross sectional view of the entirety of the stereo headphone system  8581  which is similar to the sixty-third embodiment. The stereo headphone system  8581  has a right-ear cartilage conduction unit  8524  and a left-ear cartilage conduction unit  8526 , which respectively are conical (cone)-shaped convex shapes. Piezoelectric bimorph elements  8525   a  and  8525   b  are respectively attached such that the vibrating surface side thereof contacts the unit.  FIG. 141(A)  also shows a block diagram of a sound signal source unit  8584  in the headphone system  8581 , for better understanding of the system in its entirety. 
     An added feature of the ninety-first embodiment resides in passage holes  8524   a  and  8526   a  which are respectively furnished at the center in the right-ear cartilage conduction unit  8524  and the left-ear cartilage conduction unit  8526 , a configuration that allows outside air-conducted sound to reach the eardrum from the external auditory meatus entrance even while the headphone system  8581  is being worn. The system is further furnished with shutters  8558  and  8559  driven by shutter drive units  8557   a  and  8557   b , whereby the passage holes  8524   a  and  8526   a  may be respectively occluded as needed, so that an external auditory meatus occluding effect can be obtained. In  FIG. 141(A) , the passage holes  8524   a  and  8526   a  are depicted in the unoccluded state. 
     A sound signal output from an acoustic processing circuit  8538  of the sound unit  8584  drives the piezoelectric bimorph elements  8525   a  and  8525   b  via a stereo amp  8540 , the vibration thereof being propagated to the inner wall of the external auditory meatus entrance by the right-ear cartilage conduction unit  8524  and the left-ear cartilage conduction unit  8526 , giving rise to good cartilage conduction. The sound unit  8584  is further furnished with a shutter control unit  8539 , and when outside noise at or above a predetermined level is detected by a noise detection unit  8538 , or when manually-operated unit  8509  is manually operated as needed, an occlusion signal is presented to the shutter drivers  8557   a  and  8557   b , whereby the shutters  8558  and  8559  slide, and respectively occlude the passage holes  8524   a  and  8526   a . On the other hand, when the noise detection unit  8541  does not detect outside noise at or above a predetermined level, or when the manually-operated unit  8509  is manually operated once more, an unocclusion signal is presented to the shutter drivers  8557   a  and  8557   b , whereby the shutters  8558  and  8559  slide, and the passage holes  8524   a  and  8526   a  are respectively unoccluded. 
       FIG. 141(B)  and  FIG. 141(C)  are enlarged fragmentary views of  FIG. 141(A) , showing opening and closing of the aforedescribed shutters. Identical portions have been assigned the same reference numerals. For simplicity, only the right-ear cartilage conduction unit  8524  is illustrated, but the left-ear cartilage conduction unit  8526  is similar in design.  FIG. 141(B)  is the same as  FIG. 141(A) , showing the passage hole  8524   a  in the unoccluded state. In contrast to this,  FIG. 141(C)  shows the shutter  8558  slid upwards, occluding the passage hole  8524   a . In so doing, in the state shown in  FIG. 141(B) , while obtaining cartilage conduction, it is possible at the same time for outside air-conducted sound to be transmitted to the eardrum from the external auditory meatus opening  30   a . In the state shown in  FIG. 141(C)  on the other hand, an external auditory meatus occlusion effect may be obtained in cartilage conduction. According to the configuration of the ninety-first embodiment as above, appropriate external auditory meatus occlusion effect may be obtained automatically, or through hand operation, without having to press the cartilage conduction unit or block the ear with the hand. 
     The various features of the embodiments described above are not limited to implementation in the aforedescribed embodiments, and may be implemented in other aspects as well, provided that the advantages thereof can be enjoyed by doing so. For example, the advantages of a configuration in which an external auditory meatus occlusion effect is obtained through occlusion and unocclusion of the external auditory meatus entrance by shutters as shown in the ninety-first embodiment are not limited to cases of cartilage conduction. Specifically, in the case of ordinary bone conduction as well, it is possible for appropriate external auditory meatus occlusion effect to be obtained automatically, or through hand operation, without having to block the ear with the hand. 
     In the eighty-ninth embodiment and the ninetieth embodiment, piezoelectric bimorph elements were adopted as the cartilage conduction vibration sources, but it would be possible to employ vibrators of electromagnetic type instead. In this case, the electromagnetic vibrator would suitably be situated in proximity to a portion closest to the external auditory meatus entrance (the earhole)  232 , at the outside  1828  of the cartilage of the base of the ear  28  (a location equivalent to that of the holding part  8325   a  of  FIG. 139 ). 
     Ninety-Second Embodiment 
       FIG. 142  is a system configuration diagram of a ninety-second embodiment of an aspect according to the present invention. The ninety-second embodiment is configured as a headset for use as an outgoing-talk/incoming-talk unit for a mobile telephone, which, together with the ordinary mobile telephone  1401 , makes up a mobile telephone system. In the ninety-second embodiment, as in the ninetieth embodiment of  FIG. 140 , a cartilage conduction unit is situated at a location touching an anterior region at the outside  1828  of the cartilage of the base of the ear  28 , and a headset  8681  incorporating the cartilage conduction unit is capable of communicating with the ordinary mobile telephone  1401  through a short-range communication unit  8487  such as a Bluetooth™ device or the like. As  FIG. 142  has much in common with  FIG. 140 , corresponding portions have been assigned common reference numbers, and descriptions thereof are omitted. 
     A point of difference between the ninety-second embodiment and the ninetieth embodiment of  FIG. 140  is the use of a contact microphone  8623  placed in direct contact against the head or the like of the user to sense vibration thereof, rather than an air-conduction microphone, for picking up audio. As shown in side view in  FIG. 142(A) , the contact microphone  8623  is situated touching the mastoid, which is situated in proximity to the rear from the holding part  8482   a  for the piezoelectric bimorph element. In so doing, an output unit for sound signals by cartilage conduction, and a sound input unit relying on the contact microphone  8623 , are accommodated compactly in integrated fashion within a space rearward from the auricle. In so doing, the headset  8681  will not get in the way when, for example, a helmet is worn from above. 
       FIG. 142(B) , like  FIG. 140(B) , is a system configuration diagram showing the details of the headset  8681 , together with the mobile telephone  1401 . As will be clear from  FIG. 142(B) , in the ninety-second embodiment, as in the ninetieth embodiment, the cell  8485  is situated intervening between the ear-hook unit  8482  and the contact microphone  8623 . Consequently, vibration of the anterior part  8484  is suppressed midway due to the weight of the cell  8485 , so the vibration component of the piezoelectric bimorph element  8425  that is ultimately transmitted to the contact microphone  8624  is small. 
     However, because the contact microphone  8624  directly senses vibration, despite the aforedescribed countermeasures, there is a possibility of it picking up vibration of the anterior part  8484 , transmitted from the piezoelectric bimorph element  8425 . To deal with this, as shown in  FIG. 142(B) , the signal from an acoustic processing circuit  8438  is subjected to waveform inversion by an inversion circuit  8640 , and applied to a canceller  8636 . A sound signals picked up by the contact microphone  8623  is propagated to the sound unit  8436  via the canceller  8636 , and the signal from the inversion circuit  8640  is applied to the canceller  8636  in aforedescribed manner, synthesizing the signals whereby the vibration component originating in the piezoelectric bimorph element  8425  picked up by the contact microphone  8623  is canceled, so that only sound signals generated by the vocal chords are propagated to the sound unit  8436 . 
       FIG. 143  is side views of the ear  28 , showing a modification example of the aforedescribed ninety-second embodiment. In the modification example, the position of the contact microphone is modified. Consequently, in  FIG. 143 , in order to describe this, the configuration of the head in proximity to the ear  28  is illustrated in detail, while in order to avoid complexity, illustration of the headset  8681 , except for the contact microphone, is omitted.  FIG. 143(A)  uses the aforedescribed method of illustration to show, for reference purposes, the ninety-second embodiment of  FIG. 142(A)  in which the contact microphone  8683  is situated contacting an area in proximity to a mastoid  8623   a.    
     In contrast to this,  FIG. 143(B)  is a first modification example of the ninety-second embodiment, in which a contact microphone  8723  is situated contacting an area in proximity to a lower jawbone  8623   b . Because the lower jawbone  8623   b  is close to the vocal chords, it vibrates during speech, making this a suitable location for the contact microphone  8723  to be situated. However, as the jawbone moves somewhat according to changes in the words uttered, the headset  8681  is supported flexibly in order for the contact microphone  8723  to conform to these movements. 
       FIG. 143(C)  is a second modification example of the ninety-second embodiment, in which a contact microphone  8823  is situated contacting an area in proximity the mastoid  8623   c  side of a sternomastoid muscle. Vibration of the vocal cords is propagated well through the sternomastoid muscle, and the mastoid  8623   a  side thereof vibrates during speech as well. Consequently, this region is also a suitable one for the contact microphone  8883  to be situated. However, as the mastoid  8623   a  side of a sternomastoid muscle also moves somewhat according to changes in the words uttered, the headset  8681  is supported flexibly in order for the contact microphone  8823  to conform to these movements. 
     Ninety-Third Embodiment 
       FIG. 144  is a back view and a block diagram of a ninety-third embodiment of an aspect of the present invention. The ninety-third embodiment is configured as a headset  8981  serving as an outgoing-talk/incoming-talk unit for a mobile telephone, and is of headphone type designed such that stereo listening is possible. The ninety-third embodiment has much in common with the ninety-second embodiment of  FIG. 142 , and therefore corresponding portions have been assigned the same reference numerals, omitting descriptions thereof. In the ninety-third embodiment, as in the ninety-second embodiment, cartilage conduction units are situated at locations touching an anterior part of the outside of the cartilage of the base of the ear, and a contact microphone is employed to pick up sound. 
       FIG. 144(A)  is a view of the headset  8981  of the ninety-third embodiment worn on the head, seen from the back; in order to avoid complexity, the right ear  28  and the left ear  30  are illustrated by hypothetical lines by way of the head. In the headset  8981 , a right ear unit  8924  having a right-side piezoelectric bimorph element  8924   a  and the like, and a left ear unit  8926  having a left-side piezoelectric bimorph element  8926   a  and the like, are supported on a head arm unit  8981   a . In the ninety-third embodiment, constituent elements are apportioned between the right ear unit  8924  and the left ear unit  8926 , affording a compact configuration overall which makes it possible, for example, for a helmet to be worn from above. 
     To describe in more specific terms, as shown in  FIG. 144(A) , control circuitry, such as a short-range communication unit  8487  and the like, is situated in the left ear unit  8926 , and the left-side piezoelectric bimorph element  8926   a  is supported there as well. The left-side piezoelectric bimorph element  8926   a  supported in this fashion propagates cartilage conduction from the mastoid side of the region of attachment of the auricle. Further, a contact microphone  8923 , supported by a flexible structure via an intervening left-side cell  8985   a , contacts the lower jawbone. Meanwhile, power source circuitry, such as a power supply unit  8985  and the like, is arranged in the right ear unit  8924 , and the right-side piezoelectric bimorph element  8924   a  is supported there as well. The right-side piezoelectric bimorph element  8924   a , like the left-side piezoelectric bimorph element  8926   a , propagates cartilage conduction from the mastoid side of the region of attachment of the auricle. Stereo listening is possible thereby. Further, a right-side cell  8985   b  is supported on the right ear unit  8924 . In this way, the cells, which take up space, are apportioned to the right ear unit  8924  and the left ear unit  8926 . 
       FIG. 144(B)  is a block diagram showing details of the ninety-third embodiment; portions in common with the ninety-second embodiment of  FIG. 142(B)  are assigned the same symbols, omitting descriptions. As will be clear from  FIG. 144(B) , in the ninety-third embodiment, the left-side piezoelectric bimorph element  8926   a  and the contact microphone  8923  are close together within the left ear unit  8926 , and therefore in the same manner as in the ninety-second embodiment, an inversion circuit  8640  and a canceller  8636  are furnished for canceling of vibration components originating in the piezoelectric bimorph element  8926   a  and picked up by the contact microphone  8923 . In the right ear unit  8924  on the other hand, the right-side power supply unit  8985  receives supply of power from the right-side cell  8985   b , as well as receiving supply of power from the left-side cell  8985   a  via a connecting cable inside the head arm unit  8981   a . Carrying out any necessary voltage boosting or the like on the basis of the voltage and charge capacity of the right-side cell  8985   b  and the left-side cell  8985   a , power is fed to an amplifier  8940   b  of the right ear unit  8924 , while also supplying power to the constituent components of the left ear unit  8926  through the connecting cable inside the head arm unit  8981   a . Further, an acoustic processing circuit  8438  of the left ear unit  8926  transmits left ear sound signals to an amplifier  8940   a  of the left ear unit  8926 , and transmits right ear sound signals to the amp  8940   b  of the right ear unit  8924  via the connecting cable inside the head arm unit  8981   a . In the ninety-third embodiment, vibration of the right-side piezoelectric bimorph element  8924   a  is propagated through the head arm unit  8981   a , so the component picked up by the contact microphone  8923  is sufficiently small. 
     Ninety-Fourth Embodiment 
       FIG. 145  is a back cross sectional view and a block diagram of a ninety-fourth embodiment of an aspect of the present invention. The ninety-fourth embodiment is likewise configured as a headset  9081  serving as an outgoing-talk/incoming-talk unit for a mobile telephone, and is of headphone type designed such that stereo listening is possible. The ninety-fourth embodiment has much in common with the ninety-second embodiment of  FIG. 143 , and therefore corresponding portions have been assigned the same reference numerals, omitting descriptions thereof. In the ninety-fourth embodiment, as in the ninety-second embodiment and ninety-third embodiment, cartilage conduction units are situated at locations touching an anterior part of the outside of the cartilage of the base of the ear, and a contact microphone is employed to pick up sound. 
     A point of difference between the ninety-fourth embodiment and the ninety-third embodiment is that the headset  9081  is a stereo headset of neckband type, and in association therewith, is furnished with contact microphones  9023   a  and  9023   b  and with a neckband unit  9081   a , the pair of contact microphones  9023   a  and  9023   b  being designed to pick up, from both sides, vibration of the sternomastoid muscle from the back surface of the neck. This region is close to the vocal chords and vibrates well, and as such is suited to being furnished with the contact microphones  9023   a  and  9023   b . Moreover, as discussed below, these do not pose an obstacle when wearing a helmet or the like. 
     The following specific description is based on  FIG. 145(A) .  FIG. 145(A)  is a view of the headset  9081  of the ninety-fourth embodiment worn on the head, seen from the back; as in  FIG. 144(A) , in order to avoid complexity, the right ear  28  and the left ear  30  are illustrated by hypothetical lines by way of the head. In the ninety-fourth embodiment of  FIG. 145(A) , a right ear unit  9024  having a right-side piezoelectric bimorph element  8924   a  and the like, and a left ear unit  9026  having a left-side piezoelectric bimorph element  8926   a  and the like, are supported from below by the neckband unit  9081   a . The neckband unit  9081   a  is shaped to conform to the back of the neck, the pair of contact microphones  9023   a  and  9023   b  being furnished to the inside thereof so as to lie to either side of the back surface of the neck. In so doing, vibration of the sternomastoid muscle at the back surface of the neck can be picked up in satisfactory fashion. Contact of the pair of contact microphones  9023   a  and  9023   b  against the back surface of the neck is stabilized, and vibration of the sternomastoid muscle due to vocalization from the vocal chords can be picked up in complementary fashion from both sides. 
     Like the ninety-second embodiment and the ninety third embodiment, the ninety-fourth embodiment is suited to use while wearing a helmet. In order to describe the effects of use, a cross section of a helmet  9081   b  is illustrated in  FIG. 145(A) . As is clear from  FIG. 145(A) , the inner surface of the helmet  9081   b  is of a shape loosely covering the right ear  28  and the left ear  30 , and therefore the energy of air-conducted sound generated inside the external auditory meatus of both ears  28  and  30  on the basis of cartilage conduction from the right-side piezoelectric bimorph element  8924   a  and the left-side piezoelectric bimorph element  8926   a  is prevented from dissipating to the outside from the external auditory meatus entrance, making it possible to hear sounds produced by cartilage conduction at higher volume. Moreover, because sound is not produced outside the external auditory meatus entrance due to vibration of the helmet  9081   b  or the like, external sounds audible through the helmet  9081   b  are not masked within the helmet  9081   b.    
       FIG. 145(B)  is a block diagram showing details of the configuration of the ninety-fourth embodiment, with portions in common with the ninety-third embodiment of  FIG. 144  (B) being assigned the same reference numerals, omitting descriptions thereof. As will be clear from  FIG. 145(B) , in the ninety-fourth embodiment, components of vibration of the right-side piezoelectric bimorph element  8924   a  and the left-side piezoelectric bimorph element  8926   a  propagated through the neckband unit  9081   a  and picked by the left-side contact microphone  9023   a  and the right-side contact microphone  9023   b  are sufficiently small. Consequently, the configuration involving the inversion circuit  8640  and the canceller  8683  furnished in the ninety-third embodiment for the purpose of canceling these vibration components has been omitted. 
     Ninety-Fifth Embodiment 
       FIG. 146  is a block diagram of a ninety-fifth embodiment of an aspect of the present invention. The ninety-fifth embodiment is likewise configured as a headset  9181  serving as an outgoing-talk/incoming-talk unit for a mobile telephone, and is of headphone type designed such that stereo listening is possible. The ninety-fifth embodiment has much in common with the ninety-fourth embodiment of  FIG. 145 , and therefore corresponding portions have been assigned the same reference numerals, omitting descriptions thereof. In the ninety-fifth embodiment, as in the ninety-second to ninety-fourth embodiments, cartilage conduction units are situated at locations touching an anterior part of the outside of the cartilage of the base of the ear, and a contact microphone is employed to pick up sound. 
     A difference between the ninety-fifth embodiment and the ninety-fourth embodiment is that, in order to cancel components of vibration of the right-side piezoelectric bimorph element  8924   a  and the left-side piezoelectric bimorph element  8926   a  propagated through a neckband unit  9181   a  and picked by a contact microphone  9123 , the inversion circuit  8640  and the canceller  8636  are furnished as in the ninety-third embodiment of  FIG. 144 . Further, in the ninety-fifth embodiment, unlike the ninety-fourth embodiment, the contact microphone  9123  is furnished in left-right asymmetric fashion to the neckband unit  9181   a . In specific terms, the contact microphone  9123  is furnished to a location closer to the left-side piezoelectric bimorph element  8926   a  than to the right-side piezoelectric bimorph element  8926   a.    
     As will be clear from  FIG. 146 , to counter vibration picked up from the left-side piezoelectric bimorph element  8926   a , the inversion circuit  8640  and the canceller  8636  are furnished in the same manner as in the ninety-third embodiment, and vibration components originating in the left-side piezoelectric bimorph element  8926   a  and picked up by the contact microphone  9123  are canceled. Further, in the ninety-fifth embodiment of  FIG. 146 , by furnishing an inversion circuit  9140  to counter vibration picked up from the right-side piezoelectric bimorph element  8924   a , and applying this inverted signal to the canceller  8636 , vibration components originating in the right-side piezoelectric bimorph element  8924   a  and picked up by the contact microphone  9123  are canceled. This configuration is useful for stereo listening in cases in which different sound signals are input to the right-side piezoelectric bimorph element  8924   a  and the left-side piezoelectric bimorph element  8926   a.    
     Further, in the ninety-fifth embodiment, in consideration of the fact that the right-side piezoelectric bimorph element  8924   a  is further away from the contact microphone  9123  than is the left-side piezoelectric bimorph element  8926   a , the inverted output from the inversion circuit  9140  is attenuated by an attenuation circuit  9140   a  before application to the canceller  8636 . In so doing, canceling does not become excessive at times that the picked up vibration is small. 
     The various features of the embodiments described above are not limited to the aforedescribed embodiments, and may be implemented in other aspects as well, provided that the advantages thereof can be enjoyed by doing so. For example, the features relating to concomitant use of a helmet, shown in the ninety-second to ninety fifth embodiments, can be utilized in cases not limited to ones of use in combination with a mobile telephone. For example, exchange of audio signals with outside equipment from a sound unit is not limited to short-range wireless communications, and comparable advantages can be achieved in cases of exchange through a wired connection as well. 
     Ninety-Sixth Embodiment 
       FIG. 147  is a perspective view and cross-sectional view relating to a ninety-sixth embodiment of the present invention according to an aspect of the present invention, configured as a mobile telephone  9201  and a cartilage conduction soft cover  7863  therefor in the same manner as the eighty-fourth embodiment of  FIG. 126 . The configuration of the ninety-sixth embodiment is substantially consistent with that of the eighty-fourth embodiment, and therefore the same reference numerals have been assigned to common parts, and descriptions are omitted. 
     A pair of infrared light-emitting unit  9219 ,  9220  constituting a proximity sensor for detecting that the mobile telephone  9201  is abutting an ear for purposes of a call, and with a shared infrared light proximity sensor  9221  for receiving infrared light reflected from the ear. When the proximity sensor detects that the mobile telephone  9201  has abutted the ear, the display backlight in the touch panel/large-screen display unit  9205  is switched off in order to conserve electricity, and the touch panel function is disabled in order to prevent accidental operation. This is due to the fact that the touch panel/large-screen display unit  9205  is in contact with the cheek or the like when the mobile telephone  9201  is brought up against the ear, and the touch panel may execute an undesired operation in response thereto. 
     In contrast, when an earphone plug is inserted into the external earphone jack provided to the upper left part of the mobile telephone  9201 , it is not ordinarily envisioned that the mobile telephone  9201  will be brought up against the ear and used, and therefore the possibility that touch panel/large-screen display unit  9205  is in contact with the cheek and that accidental operation will occur is low. Furthermore, were the proximity sensor to detect the finger or the like and switch off the touch panel function, this rather would also result in an undesired operation. For these reasons, the configuration is such that the touch panel function is disabled by the proximity sensor when the earphone plug has been inserted. 
     However, when the cartilage conduction soft cover  7863  is mounted in the manner of the ninety-sixth embodiment and the external earphone plug  7885  is inserted into the external earphone jack and used, the touch panel/large-screen display unit  9205  is in contact with the cheek or the like and it is possible that the touch panel will execute an undesired operation in response thereto because the cartilage conduction part  7824  is brought into contact with the ear cartilage in order to transmit vibrations thereof. Having stated such, when the configuration is such that the touch panel function is disabled by the proximity sensor when the earphone plug has been inserted, it is possible that the proximity sensor will detect a finger or the like and disable the touch panel function when an ordinary earphone is inserted into the external earphone jack in the manner described above and the mobile telephone  9201  is used. In order to solve such a problem, the ninety-sixth embodiment retains original disablement control of touch panel function based on the use a proximity sensor and an external earphone jack, and is yet configured so as to prevent accidental operation caused by the touch panel/large-screen display unit  9205  being in contact with the cheek or the like when the cartilage conduction soft cover  7863  is mounted and the cartilage conduction part  7824  is brought into contact with the ear cartilage. 
     Specifically, when a call is initiated by performing a call operation or the like by inputting the telephone number of the other party or by operating the touch panel or call button  9209   a  in order to make a call, or when there is an incoming call and the touch panel operation or a response operation using the call button  9209   a  has been performed in order to respond thereto, the touch panel function is disabled when a predetermined time (e.g., one second) has elapsed after the operation. This is due to the fact that, in these conditions, it is envisioned that the mobile telephone  9201  on which the cartilage conduction soft cover  7863  has been mounted will be brought up against the ear, and the touch panel functions are thought to be unnecessary. In order to conserve energy and notify the user that the touch panel functions are disabled, the display of the large-screen display unit  9205  is switched off and the display backlight is switched off when the touch panel functions are disabled. 
     On the other hand, a call-cutoff button  9209   b  or another mechanical switch is pressed when the call has ended, whereby the touch panel functions are enabled, and in order to notify the user of this, the display of the large-screen display unit  9205  is restarted and the display backlight is switched on. 
     It is not envisioned that the cartilage conduction part  7824  will be placed in contact with the ear cartilage during videoconferencing, even when the cartilage conduction soft cover  7863  has been mounted and the external earphone plug  7885  is inserted in the external earphone jack and used. For this reason, control for disabling and enabling the touch panel in the manner described above is not carried out during videoconferencing, and, in the same manner as in normal cases, the touch panel functions are not disabled by the proximity sensor when the earphone plug is inserted. Operation related to a call is not carried out in a state in which the earphone plug has been inserted for ordinary enjoyment of music, functions related to a call do not occur, and therefore, in the same manner as ordinary cases, the touch panel functions are not disabled by the proximity sensor when the earphone plug is inserted. 
       FIG. 148  is a block view of a mobile telephone  9201  portion of the ninety-sixth embodiment in  FIG. 147 . The mobile telephone  9201  in the ninety-sixth embodiment has much in common with the eighty-sixth embodiment in  FIG. 131 , except that the mobile telephone itself does not have cartilage conduction-related functions, so corresponding portions have been given the same reference numerals, and a description has been omitted. The ninety-sixth embodiment has a pair of infrared light-emitting units  9219 ,  9220  constituting a proximity sensor, and a shared infrared light proximity sensor  9221  for receiving infrared light reflected from the ear, as shown in  FIG. 148 . A display backlight  43  and a touch panel  9268  are provided to the touch panel/large-screen display unit  9205 , and the touch panel functions are implemented by a touch panel driver  9270  controlled by a control unit  9239 . Operations when the touch panel functions are disabled are carried out by an operating unit  9209 , which includes a call button  9209   a , a call-cutoff button  9209   b , and the like. 
       FIG. 149  is flowchart showing the function of the control unit  9239  of the ninety-sixth embodiment in  FIG. 148 . To facilitate understanding, the flowchart of  FIG. 149  mainly illustrates an abstraction of the functions for disabling and enabling the touch panel, and the ordinary functions of the mobile telephone  9201  are omitted. Therefore, various other related functions operating in parallel with and before and after the functions illustrated in  FIG. 149  are present in the ninety-sixth embodiment. 
     The flow of  FIG. 149  starts when the main power source provided to the operating unit  9209  is turned on, and in Step S 492 , initial startup and a function check of each unit are performed, as well as initiating screen display on the large-screen display unit  9205 . Next, in Step S 494 , the functions of the touch panel  9268  are enabled, and the routine advances to Step S 496 . In Step  496 , a check is performed to determine whether any of various panel operations have been performed prior to start of communications of the mobile telephone  9201 . This panel operation includes not only menu selection and other basic operations, music enjoyment, camera functions, and other operations unrelated to communication, but also input of telephone numbers and email addresses for communication, and start operations for calls and communication. When any of these operations are detected, the routine advances to Step S 498  and performs preprocessing for communication startup corresponding to the operation, and the routine advances to Step S 50 . In the case that a panel operation corresponding to Step S 496  is not detected, the routine advances directly to Step S 500 . 
     In Step S 500 , a check is performed to determine whether communication has started and videoconferencing is in progress, and if not, the routine advances to Step S 502 . In Step  502 , a check is performed to determine whether the external earphone jack  7846  is in use. This applies whether any earphone plug has been inserted into the external earphone jack  7846 . When the external earphone jack  7846  is in use, the routine advances to Step S 504 , and a check is performed to determine whether there has been an incoming call and an operation for responding thereto has been performed. If not, the routine advances to Step S 506 , and naturally, when there is no incoming call and when an operation for answering has not been performed even when there is an incoming call, the routine advances to Step S 506 . In Step S 506 , a check is performed to determine whether the call function has been started on the basis of a call operation, and if not, the routine advances to Step S 508 . When the external earphone jack  7846  is being used in this manner, the routine arrives at Step S 508  with the touch panel  9268  remaining enabled as long as the process has not entered the communication execution stage due to an incoming call or a call operation. 
     In contrast, when it has been detected in Step S 504  that an operation for answering an incoming call has been performed, the routine advances to Step S 510  and waits for one second to elapse in Step S 510 , after which the touch panel  9268  is disabled in step S 512  and the routine advances to Step S 508 . When it has been detected in Step S 506  on the basis of a call operation that the call function has been started, the routine advances immediately to Step S 512 , the touch panel  9268  is disabled, and the routine advances to Step S 508 . 
     As described above, when an incoming call answering operation or when the call function has been started, it can be considered that the touch panel functions are not required, and the touch panel  9268  is therefore disabled in Step S 512 . Although omitted from  FIG. 149  to avoid complexity, the display of the large-screen display unit  9205  is turned off and the display backlight  43  is switched off in Step S 512  at the same time that the touch panel functions are disabled, as described above. 
     The reason for waiting one second in Step S 510  is that incoming call is a passive one based on operation from another party, and the operator is therefore not necessarily prepared to answer a call in advance. Therefore, the operator may experience discomfort were the touch panel  9268  to be disabled and the display of the large-screen display unit  9205  turned off immediately after an answering operation, so the display is continued for a moment. This also has significance in that when a call is accidentally answered, a call cutoff operation can be performed immediately thereafter using the touch panel  9268 . On the other hand, when the waiting time is excessively long, it is possible that the touch panel  9268  will make contact with the cheek and produce an accidental operation as a result of the mobile telephone  9201  being brought against the ear, so the waiting time is kept to a short time to balance against these other factors. On the other hand, a call operation is an active final operation that follows an operation for choosing a contact or other required operation, and when a call is started on the basis thereof, the configuration is such that waiting time is not provided because the operator is not made to feel unsure and feel discomfort even when the display of the touch panel/large-screen display unit  9205  is turned off and the operation of the touch panel  9268  is disabled. Thus, the ninety-sixth embodiment is provided with a difference in the process of arriving at disabling the touch panel when answering an incoming call and making a call. 
     In step S 508 , a check is performed to determine whether a mechanical operation has been made to cut off a call using the call-cutoff button  9209   b  or the like, and if a mechanical operation has been made to cut off a call, the routine advances to Step S 514 , the touch panel  9268  is enabled, the call cutoff is executed in Step S 516 , and the routine arrives at Step S 518 . Although not shown in the drawing, when the touch panel functions are enabled, the display of the touch panel/large-screen display unit  9205  is restored and the display backlight  43  is simultaneously switched on in Step S 514 . On the other hand, when a mechanical operation to cut off a call in not detected in Step S 508 , the routine advances directly to Step S 518 . 
     When use of the external earphone jack  7846  is not detected in Step S 502 , the routine advances to Step S 502  and a check is performed to determine whether a call is in progress. When a call is in progress, the routine advances to Step S 522 , and a check is performed by the proximity sensor to determine whether the mobile telephone  9201  has been brought up against the ear. When the mobile telephone is detected to be abutted against the ear, the routine advances to Step S 524 , the touch panel  9268  is disabled, and the routine advances to Step S 526 . When the routine has arrived at Step S 524  and the touch panel  9268  is already disabled, the routine does nothing in Step S 524  and advances to Steps S 526 . 
     On the other hand, when a call in progress has not been detected in Step S 520 , or when the proximity sensor has made no detection in Step S 522 , the routine advances to Step S 528 , the touch panel  9268  is enabled, and the routine advances to Step S 526 . When the routine has arrived at Step S 528  and the touch panel  9268  is already enabled, the routine does nothing in Step S 528  and advances to Steps S 526 . 
     When videoconferencing is in progress in Step S 500 , control for enabling and disabling the touch panel  9268  by the proximity sensor as described above is not carried out, and the routine advances immediately to Step S 526  with the touch panel  9268  remaining enabled. Steps S 500  also serves a function for keeping the touch panel  9268  enabled without control for disabling and enabling the touch panel  9268  being carried out due to an incoming call answering operation, a call start, or a mechanical operation to cut off a call when the external earphone jack  7846  is being used. 
     In step S 526 , a check is performed to determine whether an operation to cutoff a call has been made using the touch panel  9268 . When an operation to cut off a call has been made, the routine advances to Step S 516  and the call cutoff is executed. On the other hand, when an operation to cut off a call is not detected by the touch panel  9268  in Step S 526 , the routine advances to Step S 508 . While the touch panel  9268  is disabled, the routine must naturally advance from Step S 526  to Step S 508 . In step S 508 , a check is performed to determine whether a mechanical operation has been made to cut off a call as previously described. 
     In Step S 518 , a check is performed to determine whether an operation has been performed to turn off the main power source, and if such an operation has occurred, the flow ends. On the other hand, when an operation has been performed to turn off the main power source has not been detected, the routine returns to Step S 496 , repeats Step S 496  to Step S 526 , and in accordance with conditions, performs control to enable and disable the touch panel  9268 , to display the large-screen display unit  9205  in accompaniment therewith, and to switch the display backlight  43  on and off. On the other hand, when an operation for turning off the main power source has been detected in Step S 518 , the flow ends. 
     The implementation of the present invention is not to be limited to the aforementioned embodiments, and various modifications are possible. For example, in the ninety-sixth embodiment, a difference is provided to the process by which the routine arrives as disabling the touch panel when responding to an incoming call and making a call. However, the embodiment for disabling the touch panel is not to be limited to such a configuration, and the configuration may be such that the touch panel  9268  is disabled by way of the same process when responding to an incoming call and making a call. 
     In the ninety-sixth embodiment, Step S 502 , Step S 520  to Step S 524 , and Step S 528  were omitted, and when videoconferencing is not in progress, the configuration may be such that the control of Step S 504  to Step S 516  is carried out regardless of the use of the external earphone jack  7846 . 
     Furthermore, in the ninety-sixth embodiment, it is possible to: modify the routine so that Step S 502  is substituted by a check about whether a “call-related function is in operation,” and if so, the routine advances to Step S 520 , and if not, the routine immediately advances to Step S 18 ; and use a configuration in which Step S 504  to S 516 , and Step S 526  are omitted and control carried out by the proximity sensor in Step S 520  to Step S 524 , and Step S 528  is performed regardless of the use of the external earphone jack  7846  when a call-related function, excluding videoconferencing, is in operation. 
     Ninety-Seventh Embodiment 
       FIG. 150  is a front perspective view of a ninety-seventh embodiment according to an aspect of the present invention, and is configured as a mobile telephone  9301 . The mobile telephone  9301  of the ninety-seventh embodiment is substantially consistent with the mobile telephone  8201  of the eighty-eighth embodiment, and therefore the same reference numerals have been assigned to common parts, and descriptions are omitted. The internal configuration invokes the block diagram of the twenty-sixth embodiment in  FIG. 42 . 
     The ninety-seventh embodiment differs from the eighty-eighth embodiment in that a function for describing the method for using the cartilage conduction function has been added. In similar fashion to the eighty-eighth embodiment, the ninety-seventh embodiment presents no problems to a call even when the upper edge center part is brought into contact with the ear in the manner of an ordinary mobile telephone. However, the right-side corner part  8224  and the left-side corner part  8226 , which are cartilage conduction parts, must be brought into contact with the ear in order to more effective use the functions of cartilage conduction, which is different from normal circumstances. For this reason, the ninety-seventh embodiment has a function for describing the method of use to a user who is unaccustomed to the use of a cartilage conduction mobile telephone. 
       FIG. 150(A)  is the same configuration as  FIG. 136(A) , except that the videoconferencing speaker  51 , and the pair of infrared light-emitting units  19 ,  20  and the infrared light proximity sensor  21  constituting the proximity sensor, which are omitted from  FIG. 136(A) , are illustrated. These functions are the same as those already described in the first embodiment and elsewhere and a description of each is omitted. 
       FIG. 150(B)  shows a cartilage conduction basic instructional display  9305   a  being displayed on a large-screen display unit  8205  in the ninety-seventh embodiment. The mobile telephone  9301  of the ninety-seventh embodiment displays “This is a cartilage conduction smartphone for corner listening” or another cartilage conduction basic instructional display  9305   a  for a predetermined time (e.g., five seconds) when the power is switched on. A similar display is performed when the mobile telephone  9301  is not tilted until a call is made and the other party answers, or until there is an incoming call and an operation is made to receive the call. 
       FIG. 150(C)  shows a right-corner instructional display  9305   b  being displayed on the large-screen display unit  8205  in the ninety-seventh embodiment. The mobile telephone  9301  of the ninety-seventh embodiment displays “Please bring the right corner to your ear hole” or another right-corner instructional display  9305   b  when the mobile telephone  9301  is tilted right until a call is made and the other party answers, or until there is an incoming call and an operation is made to receive the call. Being tilted to the right envisions that the mobile telephone  9301  is being held in the right hand and will be brought into contact with the right ear for a call, and such a display is carried out for urging that the right-side corner part  8224  be brought into contact with the right ear. As is clear from  FIG. 150(C) , the right-corner instructional display  9305   b  is a graphic display indicating the right-side corner part  8224  that is to be brought to the ear. 
     Similarly,  FIG. 150(D)  shows a left-corner instructional display  9305   c  being displayed on the large-screen display unit  8205  in the ninety-seventh embodiment. In the same manner is  FIG. 150(C) , “Please bring the left corner to your ear hole” or another left-corner instructional display  9305   c  is displayed when the mobile telephone  9301  is tilted left until a call is made and the other party answers, or until there is an incoming call and an operation is made to receive the call. In this case, it is envisioned that the mobile telephone  9301  is being held in the left hand and will be brought into contact with the left ear, and such a display is therefore carried out for urging that the left-side corner part  8226  be brought into contact with the left ear. In similar fashion to  FIG. 150(C) , the left-corner instructional display  9305   c  is a graphic display indicating the left-side corner part  8226  that is to be brought to the ear. 
       FIG. 151  is a flowchart showing the function of the control unit  2439  in the block view of the twenty-sixth embodiment of  FIG. 26  called on in the ninety-seventh embodiment of  FIG. 150 . To facilitate understanding, the flowchart of  FIG. 151  mainly illustrates an abstraction of the usage guidance function, and the ordinary functions of the mobile telephone  9301  are omitted. Therefore, various other related functions operating in parallel with and before and after the functions illustrated in  FIG. 151  are present in the ninety-seventh embodiment. 
     The flow of  FIG. 151  starts when the main power source provided is turned on, and in Step S 532 , initial startup and a function check of each unit are performed, as well as initiating screen display on the large-screen display unit  8205 . Next, in Step S 534 , the cartilage conduction basic instructional display  9305   a  is shown, and this is continued while the routine advances to Step SS 536  and performs a check of whether five seconds have elapsed. If five seconds have not elapsed, the routine returns to Step S 534 , Step S 534  and Step S 536  are repeated and display is continued. On the other hand, when it has been detected that five seconds have elapsed in Step S 536 , the routine advances to Step S 538  and the cartilage conduction basic instructional display  9305   a  is stopped. 
     Next, in Step S 540 , a check is performed to determine whether a predetermined number of days (e.g., two weeks) have elapsed since the start of usage of the mobile telephone  9301 ; if two weeks have not elapsed, a check is performed in Step S 542  to determine whether a function history applicable to guidance stoppage has been stored away, and when there is no applicable history, the routine advances to Step S 544 . The details of applicable history for guidance stoppage are later described. In Step S 544 , a check is performed to determine whether a call operation has been made, and if no such operation has been made, the routine advances to Step S 546  to check whether there has been an incoming call. When there has been an incoming call, the routine advances to Step S 548 . Also, when a call operation has been detected in Step S 544 , the routine advances to Step S 548 . At this point, a call has not yet started, the mobile telephone  9301  has not been brought up to the ear, and the user is viewing the large-screen display unit  8205 . 
     Next, in Step S 548 , a check is performed to determine whether the mobile telephone  9301  is tilted leftward on the basis of the acceleration of gravity detected by the acceleration sensor  49  (see  FIG. 42 ). If there is not leftward tilt, the routine advances to Step S 550 , and a check is performed in similar fashion to determine whether the mobile telephone  9301  is tilted rightward on the basis of the acceleration sensor  49 . If there is no rightward tilt, the routine advances to Step S 552 , the cartilage conduction basic instructional display  9305   a  is performed in the same manner as in Step S 534 , and the routine advances to Step S 554 . 
     On the other hand, when a leftward tilt of the mobile telephone  9301  is detected in Step S 548 , the routine advances to Step S 556 , the left-corner instructional display  9305   c  (see  FIG. 150(D) ) is performed, and the routine advances to Step S 554 . Similarly, when a rightward tile of the mobile telephone  9301  is detected in Step S 550 , the routine advances to Step S 556 , the right-corner instructional display  9305   b  (see  FIG. 150(C) ) is performed, and the routine advances to Step S 554 . 
     In Step S 554 , a check is performed to determine whether conditions have been satisfied for stopping instructional display started in Step S 552 , Step S 556 , or Step S 558 , and when the conditions have not been satisfied, the routine advances to Step S 548 , and Steps S 548  to S 558  are thereafter repeated until the conditions are satisfied. If tilting is detected during this repetition, the routine advances from the cartilage conduction basic instructional display  9305   a  to the left-corner instructional display  9305   c  of  FIG. 150(D)  or the right-corner instructional display  9305   b  of  FIG. 150(C) . The user is able to view the instructional display and suitably judge the angle for bringing the mobile telephone into contact with the ear. 
     Although omitted from the illustration in  FIG. 151  to avoid complexity, when the instructional display is being performed in Step S 552 , Step S 556 , or Step S 558 , an audio instructional announcement of the same content is made from the videoconferencing speaker  51  in coordination therewith. It is also possible to set a silence mode in which such audio is not produced. Such audio guidance from the videoconferencing speaker  51  is stopped at the same time that the corresponding display on the large-screen display unit  8205  is stopped. 
     In contrast, when it has been detected that instructional display stoppage conditions have been satisfied in Step S 554 , the routine advances to Step S 560 , instructional announcement processing and control processing are executed, and the routine advances to Step S 562 . The processing of Step S 560  stops the instructional display, controls the cartilage conduction instructional announcement by cartilage conduction from the upper frame  8227 , and furthermore performs guidance control processing such as processing of guidance stoppage applicable history. The details thereof are later described. 
     The routine immediately advances to Step S 562  when it has been detected that a predetermined number of days has elapsed from the start of usage of the mobile telephone  9301  in Step S 540 , when it has been detected that guidance stoppage applicable history has been stored in Step S 542 , or when an incoming call has been detected in Step S 546 . In other words, instructional display is not performed in any of these cases. Unneeded long-term display is bothersome to a disinterested user, and it is appropriate to avoid providing guidance when there is guidance stoppage applicable history, and furthermore, it is not timely to perform guidance when a call is not about to occur. 
     A check is performed to determine whether an operation has been performed in Step S 562  to turn off the main power source, and if such an operation has occurred, the flow ends. On the other hand, if it has been detected that an operation has been performed in to turn off the main power source, the routine returns to Step S 540 , repeats Step S 540  to Step S 562 , and performs guidance control that corresponds to conditions. On the other hand, when an operation for turning off the main power source has been detected in Step S 562 , the flow ends. 
       FIG. 152  is a flowchart showing the details of step S 554  and step S 560  shown in bold in  FIG. 151 . When the routine arrives at Step S 554  in  FIG. 151 , the flow of  FIG. 152  starts, and a check is performed in Step S 572  to determine whether an operation has been manually performed to stop instructional display using the touch panel  2468  (see  FIG. 42 ) provided to the large-screen display unit  8205 . This operation is performed in order to delete an unneeded display for a user who has understood the guidance or who has no interest in the guidance. If there is no such operation, the routine advances to Step S 574 , and a check is performed by the proximity sensor ( 19 ,  20 ,  21 ) to determine whether the mobile telephone  9301  has been brought to the ear. When such is not detected, the routine returns to Step S 548  of  FIG. 15 . Thus, Step S 572  and Step S 574  of  FIG. 152  correspond to the detailed contents of a check of the instructional display stoppage conditions in Step S 554  of  FIG. 151 . 
     When a proximity detection has been made in Step S 574 , the flow advances to Step S 576 . Step S 576  and thereafter corresponds to the detailed contents of Step S 560  of  FIG. 151 . In Step S 576 , a check is performed to determine whether the cartilage conduction function has been used in a normal manner. Specifically, a check is performed to determine whether the right-side corner part  8224 , the left-side corner part  8226 , or the center part thereof of the mobile telephone  9301  has been brought to the ear by the determination of the output of the proximity sensor ( 19 ,  20 ,  21 ), and when the right-side corner part  8224  or the left-side corner part  8226  has been brought to the ear, a detection is made as to whether this matches correct corner part (the right-side corner part  8224  during a right tilt or the left-side corner part  8226  during a left tilt) indicated by the tilting detected by the acceleration sensor  49 . When a normal usage state has not been detected, the flow advances to Step S 578 . 
     In Step S 578 , a check is performed to determine whether the mobile telephone  9301  is tilted leftward on the basis of gravity acceleration detected by the acceleration sensor  49 . If there is no leftward tilt, the routine advances to Step S 580 , and a check is similarly performed to determine whether the mobile telephone  9301  is tilted rightward on the basis of the acceleration sensor  49 . If there is no rightward tilt, the routine advances to Step S 582 , a cartilage conduction basic instructional announcement having the same content as in Step S 552  of  FIG. 151  is performed by cartilage conduction from the upper frame  8227 . The state arrived at in Step S 578  is the case in which the mobile telephone  9301  has been brought to the ear, and therefore, the routine does not ordinarily arrive at Step S 582 , and Step S 582  for announcing general information is provided because so that errant information is not announced when leftward tilt and rightward tilt cannot be judged by a special way the mobile telephone  9301  is brought to the ear. 
     On the other hand, when a leftward tilt of the mobile telephone  9301  has been detected in Step S 578 , the routine advances to Step S 586 , a left-corner instructional announcement (e.g., same text as displayed in  FIG. 150(D) ) is made by cartilage conduction from the upper frame  8227 , and the routine advances to Step S 584 . In similar fashion, when a rightward tilt of the mobile telephone  9301  has been detect in Step S 580 , the routine advances to Step S 588 , a right-corner instructional announcement (e.g., same text as displayed in  FIG. 150(C) ) is made by cartilage conduction from the upper frame  8227 , and the routine advances to Step S 584 . 
     In Step S 584 , a check is performed to determine whether a call has been started by response by another party to a call or by an operation to respond an incoming call, and if a call has not been started, the routine advances to Step S 576 , and the routine thereafter repeats Step S 576  to Step S 584  as long as a call start has been detected in Step S 584  or normal usage is not detected in Step S 576 . If the manner in which the mobile telephone is brought to the ear has been modified during this repetition and a state of normal usage is detected, instructional announcement is stopped as described below, and when tilting has been detected, a specific announcement of the angle to be used is started. Furthermore, if the mobile telephone is switched between left and right, the angle indicated in the announcement is modified. The user using the wrong manner of contact can thereby become aware of the correct manner of contact against the ear. 
     On the other hand, an instructional announcement is stopped even when the manner of contact is not correct when a call start is detected in Step S 584 . This is to ensure that an instructional announcement does not interfere with a call. Furthermore, the routine advances to Step S 592 , instructional display started in Steps S 552 , S 556 , S 558  of  FIG. 151  is stopped, and the routine advances to Step S 562  of  FIG. 151 . At this point, when an instructional announcement is in progress from the videoconferencing speaker  51 , this instructional announcement is also stopped. 
     In the flow of  FIG. 152 , the instructional display is continued until the routine arrives at Step S 592 , and there is no problem even were the display to be continued up until the start of a call when the mobile telephone  9301  is in contact with the ear. Also, if an instructional announcement from the videoconferencing speaker  51  is in progress, this instructional announcement is also continued in similar fashion until a call is started, and there is no problem because the announcement is of the same content synchronized with that being provided by cartilage conduction from the upper frame  8227 . Since an instructional display as described above and an instructional announcement from the videoconferencing speaker  51  are not particularly required when the mobile telephone  9301  is in contact with the ear, and a step for stopping instructional display similar to Step S 592  may be furthermore inserted between Step S 574  and Step S 579 . 
     On the other hand, when normal usage of the cartilage conduction function has been performed in Step S 576 , the instructional announcement is stopped in Step S 594  and the routine advances to Step S 596 . At this point, when the routine has arrived at Step S 574  from Step S 576  without going through Step S 582 , Step S 586 , or Step S 588 , the original instructional announcement is not being performed, and the routine therefore performs no action in Step S 594  and advances to Step S 596 . The routine also advances to Step S 596  when it has been detected in Step S 572  that an operation for stopping the instructional announcement has been performed manually. 
     In Step S 596 , the operation of Step S 572  or the detection of Step S 576  are recorded as history corresponding to guidance stoppage, and the routine advances to Step S 592 . The history recorded in Step S 596  is checked in Step S 542  of  FIG. 151 , and when these histories have been detected, the routine immediately arrives at step S 562  from step S 542  in  FIG. 151  as previously described, and the instructional display and instructional announcement are no longer performed. 
     Ninety-Eighth Embodiment 
       FIG. 153  is a cross-sectional view and a block view related to a ninety-eighth embodiment according to an aspect of the present invention, and is configured as a stereo headphone system  9481 . The ninety-eighth embodiment is based on the ninety-first embodiment of  FIG. 141 , and therefore descriptions of elements common to both are omitted and focus is placed on the description of the elements being added. In the block view of  FIG. 153(A) , a right-ear cartilage conduction unit  8524  and a left-ear cartilage conduction unit  8526 , which are provided with a passage hole  8524   a  and a passage hole  8526   a , respectively, in the center, can be connected to an external output jack  9446  of a mobile music player  9484  by a plug  9485 . An amplifier, a power source, and the like are not provided between the plug  9485  and the right-ear cartilage conduction unit  8524  and the left-ear cartilage conduction unit  8526 , and the right-ear cartilage conduction unit  8524  and the left-ear cartilage conduction unit  8526  a driven by the output power of the external output jack  9446  so as to produce the required cartilage conduction. 
     The mobile music player  9484  outputs a stereo sound source to the right-ear cartilage conduction unit  8524  and the left-ear cartilage conduction unit  8526  in the same manner as the sound signal source unit  8584  of  FIG. 141 . The mobile music player  9484  is provided with a short-range data communication unit  9487  based on Bluetooth (registered trademark) or the like, and is linked with an external ordinary mobile telephone. When an incoming call signal is received in the external ordinary mobile telephone, the input signal to the stereo amplifier  8540  is switched from the music signal from the acoustic processing circuit  8538  to the incoming call signal of an incoming call sound source  9466 , and notification of the incoming call is provided. The short-range data communication unit  9487  receives a call operation signal or a response to a call, and stops output from the stereo amplifier  8540  to the left-ear cartilage conduction unit  8526  using a switch  8540   a . An ordinary mobile telephone can thereby be brought to the left ear for a call by air conduction from the passage hole  8526   a . In  FIG. 153 , only a configuration for stopping output to the left-ear cartilage conduction unit  8526  is shown for simplification, but it is possible to provide a similar configuration for stopping output to the right-ear cartilage conduction unit  8524  and setting in advance the output of the right-ear cartilage conduction unit  8524  or the left-ear cartilage conduction unit  8526  to be stopped, and thereby stop output from the cartilage conduction unit of the one ear side that is brought to the ear during ordinary mobile telephone usage, to carry out a call by air conduction without by obstructed thereby. 
     The ninety-eighth embodiment of  FIG. 153  can be given an even simpler configuration as required. First, the shutter  8558  and the shutter drive unit  8557  described in the ninety-first embodiment of  FIG. 141  can be omitted, and doing so further simplifies the configuration of the right-ear cartilage conduction unit  8524  and the left-ear cartilage conduction unit  8526  having the passage holes  8524   a  and  8526   a . In this case, in accordance therewith, the shutter control unit  9439  of the mobile music player  9484  (corresponding to the shutter control unit  8539 , the noise detection unit  8538 , and the manually-operated unit  8509  of the ninety-first embodiment of  FIG. 141 ) are also omitted. It is furthermore possible to also omit the short-range data communication unit  9487 , the incoming call sound source  9466 , and the switch  8540   a . This is because the right-ear cartilage conduction unit  8524  and the left-ear cartilage conduction unit  8526  of the ninety-eighth embodiment of  FIG. 153  have passage holes  8524   a  and  8526   a , respectively, and since sound in the area can be heard by air conduction from the passage holes  8524   a  and  8526   a  while listening to music by cartilage conduction, having the user concentrate on a desired sound allows the user to be aware of an incoming call of an external mobile telephone, and it is not impossible to bring an ordinary mobile telephone to the ear for a call. In contrast, since the ears are covered or blocked using, e.g., ordinary stereo headphones or stereo earphones, it is not possible to be aware of incoming call sounds from an external mobile telephone, and the headphone or earphone of at least one of the ears must be removed in order to carry out a call using an ordinary mobile telephone. 
       FIG. 153(C)  is a side view of a modification of the ninety-eighth embodiment.  FIG. 153(A) , and  FIG. 153(B) , which is an enlarged view of the principal components thereof, are a configuration for bringing the right-ear cartilage conduction unit  8524  and the left-ear cartilage conduction unit  8526  into contact with the entrance to the external auditory meatus  30   a  using the head arm, and  FIG. 153(C)  is a configuration for fitting the cartilage conduction unit  9424  into the space between the inner side of the tragus  32  and the anthelix  28   a . Only the right ear  28  is illustrated for simplicity, but  FIG. 153(C)  is also a stereo type. As is clear from  FIG. 153(C) , the cartilage conduction unit  9424  for the right ear of the modification has a passage hole  9424   a  that substantially matches the entrance of the external auditory meatus  30   a.    
       FIG. 154  is a table showing measurement values of the ninety-eighth embodiment. Measurements were carried out by connecting the stereo cartilage unit in the modification of  FIG. 153(C)  to the mobile music player  9484  of  FIG. 153(A) . The “Output Voltage (mVrms)” shown in  FIG. 154  is the root-mean-square value (the half-wave peak height when viewed with an oscillograph divided by the square root) of when the output of the external output jack  9446  in an unloaded state is measured using a voltmeter while the volume of the stereo amplifier  8540  is modified. Measurement was carried out by generating a pure sound of 1 kHz. As is clear from  FIG. 154 , the root-mean-square value of the maximum output of the mobile music player  9484  of the ninety-eighth embodiment is one volt. 
     The “Vibration Acceleration (dB)” of  FIG. 154  is the vibration acceleration on the outer side of the tragus when the cartilage conduction unit  9424  is connected to the mobile music player  9484  having an output capacity such as that described above and vibrations are transmitted from the inner side of the tragus. The decibel reference value in  FIG. 154  is 10 −6  m/sec 2 . This is also a measurement of the vibration acceleration obtained while generating a pure sound of 1 kHz from the stereo amplifier  8540  and modifying the volume. The vibration source of the cartilage conduction unit  9424  used for measurement was a 0.8-μF piezoelectric bimorph element, and a voltage substantially equal to the voltage of the external output jack  9446  measured in an unloaded state can be deemed to be inputted to the piezoelectric bimorph element in a connected state. 
     The “Psychological Responses” of  FIG. 154  were obtained from a study of healthy subjects using, as an example, the manner in which measurement values such as those noted above sound to an actual person (these results must be judged with consideration given to variability in individual differences). As shown in “Psychological Responses” of  FIG. 154 , the audible threshold value when a pure sound of 1 kHz is generated from the stereo amplifier  8540  is 14.6 dB and corresponds to a volume level of 25 of the stereo amplifier  8540  (in this case, it can be considered that an effective voltage of about 3.3 mV substantially equivalent to the output voltage from the stereo amplifier  8540  is inputted to the piezoelectric bimorph element). Therefore, a pure sound of 1 kHz produced by cartilage conduction can be heard as a larger noise when the input voltage is increased above this level. 
     Next, music (pop music) was outputted from the stereo amplifier  8540  and the level that can be comfortably heard by cartilage conduction (a state perceived as being not too loud and not too quiet) was studied. As shown in “Psychological Responses” of  FIG. 154 , the subjects responded that music can be comfortably heard when the volume level of the stereo amplifier  8540  is set to 4 (in this case, it can be considered that an effective voltage of about 400 mV substantially equal to the output voltage from the stereo amplifier  8540  is inputted to the piezoelectric bimorph element). 
     It is possible to consider that comfortably listening to music is possible with a combination of a sound source device having a maximum output to the exterior of 500 mVrms or more and a cartilage conduction unit that achieves a vibration acceleration of 50 dB (reference value=10 −6  m/sec 2 ) or more to the rear surface side of the tragus when there is input of 200 mVrms by connection to an external output of the sound source device. 
       FIG. 155  is a circuit diagram showing the details of a combination circuit of a voltage booster circuit and an analog output amplifier that can be used in the seventy-fourth embodiment and the seventy-fifth embodiment shown in  FIG. 114  and  FIG. 115 . The circuit shown in  FIG. 115  can be used as a part of an IC of the driver circuit  7003  in the seventy-fourth embodiment or the driver circuit  7103  in the seventy-fifth embodiment, and may be constituted as a stand-alone IC. In  FIG. 155 , identical components have been assigned the same reference numerals as in  FIGS. 114 and 115 , and a description thereof is omitted. 
     In the seventy-fourth embodiment and the seventy-fifth embodiment, a charge pump circuit is illustrated as the voltage booster circuit  7054 , but a switching regulator is used as the voltage booster circuit unit in the circuit of  FIG. 155 . Specifically, the voltage booster circuit in  FIG. 155  is composed of a switching regulator configured from a switching control unit  7054   b , an inductance  7054   c , a diode  7054   d , a capacitor  7054   e , and the like. An output voltage of 15 volts is generated in an output unit  7054   f  on the basis of the voltage fed from a power management circuit  7053 . Also, a reference voltage output unit  7054   g  divides the voltage of the output unit  7054   f  using 100 kΩ resistances to generate a reference voltage  7054   g  for amplifier output. 
     Also, 15 volts of the output unit  7054   f  is applied to the power supply (VCC) of an analog amplifier unit  7040 . The reference voltage  7054   g  is applied to a non-inverted input of CH 1  of the analog amplifier unit  7040 . An audio signal from the acoustic processing unit  7038  (corresponding to the AD conversion circuit  7138   a , the digital acoustic processing circuit  7138 , and the DA conversion circuit  7138   b  in the case of the seventy-fifth embodiment) is inputted to the inverted inputs of CH 2  and CH 4  of the analog amplifier unit  7040 . An audio signal is outputted from the outputs of CH 2  and CH 4  of the analog amplifier unit  7040 , and drives the piezoelectric bimorph element  7013 . An enable signal from the control terminal  7003   a  is inputted to the enable terminals (ENB) of the switching control unit  7054   b  and analog amplifier unit  7040 , the switching control unit  7054   b  and the analog amplifier unit  7040  are set in an active state when the piezoelectric bimorph element  7013  is driven, and the functioning of the switching control unit  7054   b  and the analog amplifier unit  7040  are stopped when vibrations of the piezoelectric bimorph element  7013  are stopped (videoconferencing mode and the like). 
     Ninety-Ninth Embodiment 
       FIG. 156  is a diagram of the system of a ninety-ninth embodiment according to an aspect of the present invention. The ninety-ninth embodiment is configured as a headset  9581 , which is an outgoing-talk/incoming-talk unit for a mobile telephone, in the same manner as the eighty-ninth embodiment of  FIG. 139 , and constitutes a mobile telephone system together with an ordinary mobile telephone  1401 . The ninety-ninth embodiment of  FIG. 156  has much in common with the eighty-ninth embodiment of  FIG. 139 , and therefore parts that are in common have been given like reference numerals, and a description thereof has been omitted. 
     The ninety-ninth embodiment of  FIG. 156  differs from the eight-ninth embodiment of  FIG. 139  in that an elongation unit  9582   b  for making contact with the front side (the opposite side of the entrance  232  to the external auditory meatus) of the tragus  32  is provided to the ear-hooking unit  9582 . As shown in  FIG. 156(A) , the rear inner edge  9582   a  of the ear-hooking unit  9582  thereby makes contact with the rear part (the mastoid process side of the auricle attachment region) of the outer side  1828  of the cartilage of the base of the ear  28 , the elongation unit  9582   b  makes contact with the front side of the tragus  32 , and the cartilage around the entrance  232  to the external auditory meatus is sandwiched between the two. 
     This state is significant in two ways. First, the configuration is such that the cartilage of the ear is sandwiched from the outer side of the ear  28  in front of and behind the entrance  232  to the external auditory meatus as described above, and wearing is therefore stable and the ear-hooking unit  9582  makes stable contact with suitable pressure on the rear part (the mastoid process side of the auricle attachment region) of the outer side  1828  of the cartilage of the base of the ear  28  and the front side of the tragus  32 . In other words, the elongation unit  9582   b  serves as a support for bringing the rear inner edge  9582   a  of the ear-hooking unit  9582  into contact with the rear part (the mastoid process side of the auricle attachment region) of the outer side  1828  of the cartilage of the base of the ear  28 , and conversely, the rear inner edge  9582   a  of the ear-hooking unit  9582  serves as a support for bringing the elongation unit  9582   b  into contact with the front side of the tragus  32 . Additionally, since the ear  28  is sandwiched between from the front and rear on the outer side, there is nothing covering the entrance  232  to the external auditory meatus. Therefore, it is obvious that air-conducted sound from the exterior is not obstructed from entering the ear, and, e.g., even if it appears that the ear is covered as in the ninety-eighth embodiment of  FIG. 153 , as long as there is a passage hole, it is possible to avoid trouble with persons who are not aware of the fact that air-conducted sound from the exterior can be sufficiently heard, and to avoid contradictions with regulations or the like that do not envision such a fact. 
     Second, the rear part (the mastoid process side of the auricle attachment region) of the outer side  1828  of the cartilage of the base of the right ear  28  and the front side of the tragus  32  are both locations in which good cartilage conduction can be obtained, and contact parts for sandwiching the ear  28  from the front and rear in order to ensure holding both pressure function as cartilage conduction parts. In other words, the vibrations of piezoelectric bimorph element  8325  transmitted to the holding part  8325   a  shown in  FIG. 156(B)  are conducted through the ear-hooking unit  9582  itself and are transmitted to the rear inner edge  9582   a  and elongation unit  9582   b  thereof. That vibrations are transmitted from the holding part  8325   a  to the elongation unit  9582   b  can be understood from the fact that, e.g., vibrations of the right-ear cartilage conduction unit  6124  are transmitted to the left-ear cartilage conduction unit  6126  via the linking unit  6127  in the sixty-fifth embodiment of the  FIG. 97 . In other words, the portion between the rear inner edge  9582   a  and the elongation unit  9582   b  in the ear-hooking unit  9582  constitutes the linking unit for transmitting vibrations therebetween. 
     As shown in  FIG. 156(B) , the direction of vibrations of the piezoelectric bimorph element  8325  is the direction that crosses the center axis of the entrance  232  to the external auditory meatus as indicated by the arrow  8325   b  (corresponding to the substantially anterior-posterior direction of the face). In an embodiment of the mobile telephone, the direction of vibrations of the piezoelectric bimorph element  8325  is advantageously set to be the direction along the center axis of the entrance  232  to the external auditory meatus (corresponding to the lateral direction of the face and the direction in which sound enters from the exterior), whether the mobile telephone is brought to the ear in a state such as  FIG. 2  or whether the mobile telephone is brought to the ear in a state such as  FIG. 21 . However, when vibrations from the rear part (the mastoid process side of the auricle attachment region) of the outer side  1828  of the cartilage of the base of the ear  28  and the front side or the like of the tragus  32  are to be transmitted in the manner described above, it is advantageous to set the direction of vibrations of the piezoelectric bimorph element  8325  to be the direction that crosses the center axis of the entrance  232  to the external auditory meatus (corresponding to the substantially anterior-posterior direction of the face). 
       FIG. 157  is a side view of the ear-hooking unit in the various modifications of the ninety-ninth embodiment shown in  FIG. 156 . As shown in  FIG. 156(A) , the ninety-ninth embodiment is configured so that the rear inner edge  9582   a  of the ear-hooking unit  9582  makes contact with the rear part (the mastoid process side of the auricle attachment region) of the outer side  1828  of the cartilage of the base of the ear  28 , the elongation unit  9582   b  makes contact with the front side of the tragus  32 , and the cartilage around the entrance  232  to the external auditory meatus is sandwiched by the two. In this case, the distance between the front side of the tragus  32  and the rear part of the outer side  1828  of the cartilage of the base of the ear  28  differs depending on age, sex, and other individual differences. Therefore, in the ninety-ninth embodiment, the configuration is such that a plurality of sizes is prepared and customers select a size that fits. In contrast, the modification of  FIG. 157  is configuration so that the distance is variable, allowing use by anyone. 
     Described more specifically,  FIG. 157(A)  is a first modification of the ninety-ninth embodiment, and the ear-hooking unit  9582  overall is composed of an elastic body  9582   c . The elongation unit  9582   b  can thereby elastically open as indicated by the arrow  9582   d , and the ear-hooking unit  9582  can be fitted so that the rear inner edge  9582   a  of the ear-hooking unit  9582  makes contact with the rear part (the mastoid process side of the auricle attachment region) of the outer side  1828  of the cartilage of the base of the ear  28 , and the elongation unit  9582   b  makes contact with the front side of the tragus  32 . As described in the fifth embodiment of  FIG. 11  to the tenth embodiment of  FIG. 19  and elsewhere, the use of an elastic material that has acoustic impedance approximating that of ear cartilage allows vibrations to be transmitted by the elastic body to the elongation unit  9582   b.    
       FIG. 157(B)  is a second modification of the ninety-ninth embodiment. The ear-hooking unit  9582  overall is composed of a material having ordinary hardness and has a soft structure  9582   f  for narrowing or otherwise reducing the space between the rear part  9582   e  and the elongation unit  9582   b , and the elongation unit  9582   b  can thereby be elastically opened as indicated by the arrow  9582   d . Also, the soft structure  9582   f  is a linking unit for transmitting vibrations. The soft structure  9582   f  is filled with an elastic body  9582   g  in order to reinforce the soft structure  9582   f  and obtain a smooth appearance. 
       FIG. 157(C)  is a third modification of the ninety-ninth embodiment. The ear-hooking unit  9582  overall is composed of a material having ordinary hardness, the rear part  9582   e  and the elongation unit  9582   b  are rotatably linked with a rotating shaft  9582   h , and adding a spring to the rotating shaft  9582   h  portion endows the elongation unit  9582   b  with elasticity in the clockwise direction as viewed above the drawing. The elongation unit  9582   b  can thereby elastically open as indicated by the arrow  9582   d . Also, the joining part produced by the rotating shaft  9582   h  serves as a linking part for transmitting vibrations. 
       FIG. 157(D)  is a fourth modification of the ninety-ninth embodiment and has essentially the same configuration as the third modification of  FIG. 157(C) , so the principal components are illustrated in an enlarge fashion. The fourth modification of  FIG. 157(D)  is configured so that the rotating shaft  9582   i  can be rotatably adjusted with a slotted screwdriver, this rotation makes it possible to adjust, in the clockwise direction as viewed from above the drawing, the strength of the elasticity of the elongation unit  9582   b  produced by the spring. Adjustment can thereby be carried out so that a suitable contact pressure can be obtained regardless of individual differences. An indicator  9582   j  is provided to the rotating shaft  9582   i , and the indicator is aligned with a scale  9582   k , whereby contact pressure can be visually confirmed. This allows the contact pressure on either ear to be adjusted, and by aligning the indicator  9582   j  to the same scale  9582   k  as the firstly adjusted ear, the contact pressure on the left and right can be adjusted so as to be the same when audio information is to be heard in stereo by cartilage conduction by wearing the same ear-hooking units on the left and right ears. Naturally, it is also possible to make adjustments so that the left and right contact pressures are different in accordance with preference. In this case as well, the scale  9582   k  and the indicator  9582   j  serve as adjustment references. 
     The various features of each of the embodiments described above are not limited to individual embodiments, but rather can be substituted or combined, as appropriate, with features from other embodiments. For example, when vibrations are to be transmitted from the mastoid process side of the auricle attachment region or the front side of the tragus, or elsewhere, providing a configuration in which the direction of vibration of the cartilage conduction vibration source is the direction that crosses the center axis of the entrance to the external auditory meatus (corresponding to the substantially anterior-posterior direction of the face) is not limited to the case in which the cartilage vibration source is the piezoelectric bimorph element  8325  as in the ninety-ninth embodiment, and such a configuration is also advantageous when an electromagnetic vibrator is used as the cartilage conduction vibration source. 
     One-Hundredth Embodiment 
       FIG. 158  perspective view and a cross-sectional view of a one-hundredth embodiment according to an aspect of the present invention, and is configured as a mobile telephone  9601 . Excluding the structure and arrangement of the cartilage conduction vibration source composed of a piezoelectric bimorph element, the one-hundredth embodiment is the same as the forty-sixth embodiment shown in  FIG. 69 , and illustration other than the required portions will be omitted the description, and the same reference numerals are used for the common portions in the illustration portions, omitting descriptions unless necessary. 
     As shown in  FIG. 158(A) , elastic body units  4263   a ,  4263   b ,  4263   c , and  4263   d  that serve as protectors are provided to the mobile telephone  9601  of the one-hundredth embodiment in the same manner as the forty-sixth embodiment of  FIG. 69 . Also, the inner side of the elastic body units  4263   a ,  4263   b  in the upper two corners double as units for holding a piezoelectric bimorph module  9625 , and the outer side of the elastic body units  4263   a ,  4263   b  double as cartilage conduction units that make contact with the ear cartilage. 
     The mobile telephone  9601  of the one-hundredth embodiment differs from the forty-sixth embodiment of  FIG. 69  in terms of the structure of the piezoelectric bimorph module  9625  held on the inner side of the elastic body units  4263   a ,  4263   b  in the upper two corners. As shown in  FIG. 158(B) , in the piezoelectric bimorph module  9625 , the two ends of a metal plate  9697  protrudingly extend outward from a package unit  9625   a . These extended two end parts of the metal plate  9697  are bent parts  9697   a ,  9697   b  and support parts  9697   c ,  9697   d . A vibration unit  9625   b  and a circuit unit  9636  are sealed inside the package unit  9625   a . Also, the package unit  9625   a  has a minimum required thickness for protecting the vibration unit  9625   b  and the circuit unit  9636 , and the vibration unit  9625   b  of the piezoelectric bimorph module  9625  has an extremely thin shape. Thus, the piezoelectric bimorph module  9625  of the one-hundredth embodiment is a module component in which circuit portions have been sealed in a package. The piezoelectric bimorph module  9625  is a thin component in the longitudinal direction of the mobile telephone  9601  as described above, and as shown in the cross section of the support part  9697   d  of  FIG. 158(C) , the metal plate  9697  and the vibration unit  9625   b  are given adequate width in the vertical direction, ensuring the vibration power and strength of the metal plate  9697 . 
     The piezoelectric bimorph module  9625  is configured so as to be supported by a metal plate  9697  bent in the manner described above, and holding the support parts  9697   c ,  9697   d  in substantially the center of the inner side of the elastic body units  4263   a ,  4263   b  in the manner shown in  FIG. 158(B)  makes it possible to bring the thin package unit  9625   a  including the vibration unit  9625   b  into an arrangement near to the front surface side (the GUI display unit  3405  side) of the upper part of the mobile telephone  9601 , and to ensure layout space  9601   a  for arranging other components in the upper part of the mobile telephone  9601 . Even when the metal plate  9697  has such a bent structure, vibrations of the vibration unit  9625   b  are transmitted from the support parts  9697   c ,  9697   d , which are the end parts of the metal plate, to the elastic body units  4263   a ,  4263   b , respectively, and the elastic body units  4263   a ,  4263   b  can be made to function as suitable cartilage conduction units. Acoustic characteristics for cartilage conduction are designed on the basis of the behavior of the vibration of the structure overall in which both ends of the piezoelectric bimorph module  9625  are supported on such elastic body units  4263   a ,  4263   b . Acoustic characteristics are adjusted as required using an equalizer function of the circuit unit  9636  as described below. 
     Since the vibration unit  9625   b  becomes closer to the ear when the package unit  9625   a  is brought into an arrangement near to the front surface side of the upper part of the mobile telephone  9601 , air-conducted sound generated from the vibration unit  9625   b  can be heard better from the front surface side of the upper part of the mobile telephone  9601 , and in the event that conventional listening is used in conformance with  FIG. 137(B) , the voice of another party can be heard together with air conduction. When designing with such an intention, a hole for passing air-conducted sound may be provided to the front surface side of the upper part of the mobile telephone  9601 . 
     Depending on the design of the mobile telephone  9601 , the piezoelectric bimorph module  9625  may be in an upside down arrangement to thereby allow the package unit  9625   a  to be brought into an arrangement close to the rear surface side of the upper part of the mobile telephone  9601 , and this configuration also ensures layout space for arranging other components in the upper part of the mobile telephone  9601 . This arrangement allows for a layout in which the package unit  9625   a  does not interfere with an in-camera or other component arranged on the front surface side of the mobile telephone  9601 . 
       FIG. 159  is a schematic cross-sectional view and a circuit diagram showing the details of the structure of the piezoelectric bimorph of the one-hundredth embodiment shown in  FIG. 158 . The same reference numerals are used for the same portions as in  FIG. 158 , omitting descriptions unless necessary.  FIG. 159(A)  is a schematic cross-sectional view for describing the structure of principal components of the piezoelectric bimorph module  9625 , and the intermediate portion of the vibration unit  9625   b  constituting a majority of the length has the same structure as the two end portions, and a description thereof is omitted in the interest of saving space in the enlarged drawing. The vibration unit  9625   b  shown in  FIG. 158  corresponds to piezoelectric ceramic plates  9698 ,  9699  laminated to both sides of the metal plate  9697  in  FIG. 159 . The piezoelectric ceramic plates  9698 ,  9699  are extremely thin in the anterior-posterior direction of the mobile telephone  9601 , yet the support part  9697   d  of the metal plate  9697  shown in  FIG. 158(C)  has adequate thickness in the vertical direction. 
     The circuit unit  9636  is insulated and mounted on the metal plate  9697 , the metal plate  9697  serving as a shared electrode of the piezoelectric ceramic plates  9698 ,  9699  is connected to the circuit unit, and opposing electrodes  9698   a ,  9699   a  of the piezoelectric ceramic plates  9698 ,  9699  are collectively connected to the circuit unit. An insulated through-hole  9697   e  is provided in the metal plate  9697  in order to connect the opposing electrode  9698   a  to the opposing electrode  9698   b . The package unit  9625   a  covers these structures with a minimum required thickness for protection, and the piezoelectric bimorph module  9625  has an extremely thin shape. Four terminals  9636   a  (for power supply and sound signal input) extend from the circuit unit  9636  and are exposed from the package unit  9625   a . Collectively arranging the four terminals  9636   a  inside (the side to which the bent parts  9697   a ,  9697   b  extend) the piezoelectric bimorph module  9625  as shown in  FIG. 159(A)  is advantageous in terms of mounting. 
       FIG. 159(B)  is a circuit diagram of the circuit unit  9636 , and the four terminals  9636   a  of  FIG. 159(A)  correspond to power supply terminals Vcc, G and sound signal input terminals IN 1 , IN 2 , respectively in  FIG. 159(B) . The power supply terminal Vcc and ground terminal G supply power voltage to an acoustic processing circuit  9638  and a voltage booster circuit  9654 , and the voltage booster circuit  9654  supplies boosted power to an amplifier  9640 . The acoustic processing circuit  9638  is provided with an EEPROM  9638   a  for storing constants or processing tables for equalization for obtaining vibrations as an adequate cartilage conduction vibration source. These constants or processing tables are essentially written to the EEPROM  9638   a  at the time of shipment of the piezoelectric bimorph module  9625 , but may also be written after having been assembled in the mobile telephone  9601 . Sound signals inputted from the input terminals IN 1 , IN 2  to the acoustic processing circuit  9638  are inputted to the amplifier  9640  after acoustic processing, and are each outputted from the output terminals OUT 1 , OUT 2  of the amplifier  9640  to the metal plate  9697  serving as the shared electrode and the opposing electrodes  9698   a ,  9699   a.    
       FIG. 160  is cross-sectional view for describing the configuration for mass-producing the piezoelectric bimorph module in the one-hundredth embodiment. The same reference numerals are used for the same portions as  FIG. 158 , a description having been omitted unless necessary. The portions already described in  FIG. 158  are not depicted and not assigned reference numerals in order to avoid complexity.  FIG. 160(A)  and  FIG. 160(B)  conceptually show the same structure as  FIG. 158(A) , but in terms of actual dimensions, the mobile telephone  9601  shown in  FIG. 160(A)  has greater width than the mobile telephone  9601  shown in  FIG. 160(B) . (In  FIG. 160(B) , an example is shown in which the package unit  9625   a  is brought into an arrangement near the rear surface side of the upper part of the mobile telephone  9601 , but since the structure as a piezoelectric bimorph module  9625  does not vary, the arrangement is not currently related to the description below. The arrangement is later described separately.) 
     As described above, the mobile telephones  9601  in  FIG. 160(A)  and  FIG. 160(B)  have different widths, but the length and internal configuration of the package unit  9625   a  are mutually shared, as indicated by the dashed lines  9625   c ,  9625   d . Standardizing the package unit  9625   a  in this manner allows compatibility with various mobile telephones by merely modifying the length of the metal plate  9697  protruding from the package unit  9625   a , and the bent state of the bent parts  9697   a ,  9697   b  and the support parts  9697   c ,  9697   d . In  FIG. 160(A)  and  FIG. 160(B) , the mobile telephone  9601  shows as an example the case in which the widths are different, but even if the widths in terms of external appearance are the same, the size of the of the elastic bodies  4263   a ,  4263   b  may be different depending on the mobile telephone. In this case as well, standardizing the package unit  9625   a  in the manner described above allows compatibility with elastic bodies  4263   a ,  4263   b  having various sizes by merely modifying the length of the metal plate  9697  and the bent state of the bent parts  9697   a ,  9697   b  and the support parts  9697   c ,  9697   d.    
     It was described above that a hole may be provided for passing air-conducted sound to the front surface side of the upper part of the mobile telephone  9601  in order to hear air-conducted sound generated from the vibration unit  9625   b  when listening in a conventional manner in conformity with  FIG. 137(B) . As an example of such a case,  FIG. 160(A)  illustrates, for reference, a design in which a hole  9601   b  for air-conduced sound transit is provided near the vibration unit  9625   b . The hole  9601   b  may be the same as that provided for an ordinary air conduction speaker. 
     Herein, the arrangement of  FIG. 160(B)  will be supplemented. As previously described, depending on the design of the mobile telephone  9601 , the package unit  9625   a  can be brought into an arrangement near the rear surface side of the upper part of the mobile telephone  9601  by placing the piezoelectric bimorph module  9625  in an upside-down arrangement.  FIG. 160(B)  is used for specifically showing this arrangement, and in this case, available space can be ensured on the front surface side (the GUI display unit  3405  side) of the upper part of the mobile telephone  9601  as illustrated in the drawing. This arrangement allows for a layout in which the package unit  9625   a  does not interfere with an in-camera or other component arranged on the front surface side of the mobile telephone  9601 . 
       FIG. 160(C)  shows an arrangement in which the thin package unit  9625   a  including the vibration unit  9625   b  is brought near to the front surface side (the GUI display unit  3405  side) of the upper part of the mobile telephone  9601  without bending the metal plate  9697  protruding from the package unit  9625   a  in the piezoelectric bimorph module  9625  in which the length of the package unit  9625   a  is the same as that described above. Such a design is also possible as long as it is permitted by the position of the package unit  9625   a  and the support mechanism produced by the elastic bodies  4263   a ,  4263   b . Thus, the configuration for standardizing the package unit  9625   a  can be made compatible with various mobile telephones regardless of whether the metal plate  9697  is bent. In the case of a support such as in  FIG. 160(C) , when the mobile telephone  9601  is narrow and the metal plate  9697  is too long, the two ends thereof may be cut, as appropriate. 
       FIG. 160(D)  and  FIG. 160(E)  shown standardized articles of the piezoelectric bimorph module  9625  in which the package unit  9625   a  described above has been standardized, and the package unit  9625   a  as well as the metal plate  9697  protruding from the package unit  9625   a  can be mass produced to the same length. In this case, the metal plate  9697  protruding from the package unit  9625   a  is made sufficiently long so as to be compatible with various mobile telephones with consideration also given to the case of bending. In the case that the metal plate  9697  is not to be bent, it is possible to cut off the unnecessary portions  9697   e ,  9697   f  of the metal plate  9697  in a subsequent step to provide customization in accordance with customer needs, as shown in  FIG. 160(D) . On the other hand, when the metal plate  9697  is to be bent, it is possible to cut off the unnecessary portions of the metal plate  9697  and bend the bent parts  9697   a ,  9697   b  and the support parts  9697   c ,  9697   d  in a subsequent step to provide customization in accordance with customer needs, as shown in  FIG. 160(E) . Depending on customer needs, it is also possible to provide an un-machined standardized article in the states shown in  FIG. 160(D)  and  FIG. 160(E) . 
     The various features of each of the embodiments described above are not to be restricted to the individual embodiments, but rather can be substituted or combined with other embodiments, as appropriate. For example, the one-hundredth embodiment shows the case in which the piezoelectric bimorph module is supported at both ends by elastic bodies at both corners of the upper part of the mobile telephone, and the feature in which the piezoelectric bimorph module shown in the one-hundredth embodiment is arranged near the front surface or the back surface of the mobile telephone to provide space is not limited to the case in which the piezoelectric bimorph module is supported at both ends, and it is also useful when the piezoelectric bimorph module is supported by hard support part or supported in a cantilever configuration. Also, the feature of the thin circuit-integrated module shown in the one-hundredth embodiment and the standardization thereof is no limited to the one-hundredth embodiment, and can also be applied to various embodiments. 
     One-Hundred First Embodiment 
       FIG. 161  is a block view related to a one-hundred first embodiment according to an aspect of the present invention, and is configured as a mobile telephone based on cartilage conduction. The detailed configuration is the same as the embodiments described above, portions not directly related to the description are shown in rough block form in order to avoid complexity in  FIG. 161 , and a detailed description thereof is omitted. 
     The one-hundred first embodiment of  FIG. 161  has an application processor  9739  and a power management circuit  9753  in an ordinary mobile telephone  9701 . The application processor  9739  controls the principal components  9745  of a mobile telephone as well as the mobile telephone  9701  overall. The power management circuit  9753  supplies power to the mobile telephone  9701  overall in coordination with the application processor  9739 . An analog output amplifier  9740  drives a piezoelectric bimorph element  9725  that serves as a cartilage conduction vibration source on the basis of sound output outputted from the application processor  9739  and processed in an acoustic processing circuit  9738 . The power management circuit  9753  supplies drive power to the analog output amplifier  9740  via a voltage booster circuit  9754 . The details of such a configuration are the essentially same as the seventy-second embodiment shown in  FIG. 107 , and the seventy-fourth embodiment to the seventy-sixth embodiment shown in  FIG. 114  to  FIG. 116 , and elsewhere. 
     The one-hundred first embodiment of  FIG. 161  furthermore has a low-pass filter  9740   a  provided between the analog output amplifier  9740  and the piezoelectric bimorph element  9725 , the low-pass filter being used for allowing signals in a sound frequency region for driving the piezoelectric bimorph element  9725  to pass and cutting impact pulses in the high-frequency region that are produced by the piezoelectric bimorph element  9725  due to impacts caused by dropping or the like of the mobile telephone  9701 . 
     The piezoelectric bimorph element  9725  is provided to a corner part  9701   d , which is an advantageous location for making contact with the tragus and other ear cartilage, in the same manner as other embodiments. However, the corner part  9701   d  is also a location that easily experiences direction impacts due to dropping or the like, as previously described. The piezoelectric bimorph element  9725  deforms in accordance with applied voltage, can therefore be used as an output element for generating cartilage conduction vibration by application of a sound signal  9725   a  using this property, and can conversely also function as a voltaic element for generating voltage when deformation is applied from the exterior. The analog output amplifier  9740  is liable to be destroyed when impact pulses in a high-frequency range are generated from the piezoelectric bimorph element  9725  by dropping and other impacts and the impact pulses flow back to the output of the analog output amplifier  9740 . 
     The low-pass filter  9740   a  is provided between the analog output amplifier  9740  and the piezoelectric bimorph element  9725  in order to prevent such situations, and when an impact pulse  9725   b  in a high-frequency region is generated from the piezoelectric bimorph element  9725 , it is prevented from being transmitted to the analog output amplifier  9740 , as indicated by the imaginary line  9725   c  were the low-pass filter  9740   a  not be present. As described above, the low-pass filter  9740   a  allows signal signals  9725   a  in the sound frequency range for driving the piezoelectric bimorph element  9725  to pass. 
     Generally, the sampling frequency of an AD converter in a mobile telephone is 8 kHz, and that which can be quantized is up to 4 kHz, and therefore, sound signals that are used are kept to about 3.4 kHz. Also, the transmission efficiency of the vibrations is reduced from around 3 kHz across a high-frequency region in the frequency characteristics of ear cartilage, as described in  FIG. 132  and elsewhere. Therefore, by using a low-pass filter  9740   a  that allows sound signals of specifically about 4 kHz or less, there is no problem in driving the piezoelectric bimorph element  9725  and it is possible cut impact pulses  9725   b  in a high-frequency range that are generated from the piezoelectric bimorph element  9725  by dropping and other impacts. 
     The sampling frequency in a PHS or IP telephone is 16 kHz, and quantization up to 8 kHz is possible, so sound signals that are used are about 7 kHz. Also, as previously described, cartilage conduction in a broad sense may be defined as conduction in which direct vibrations as well as cartilage-air conduction contribute to vibration of the tympanic membrane, and in actuality, in a state in which the external auditory meatus occlusion effect has not occurred, the frequency range of sound that can be heard by direct air conduction from the piezoelectric bimorph element  9725  can be increased. In this case, the piezoelectric bimorph element  9725  is configured to vibrate in a region up to about 7 kHz that can be used in a PHS or an IP telephone. In the future, a cartilage conduction in a broad sense that includes a direct air conduction component is anticipated even in a mobile telephone from improvements in data communication rates, and in this case as well, it is possible to consider causing the piezoelectric bimorph element  9725  to vibrate in a region up to about 7 kHz. Therefore, a low-pass filter  9740   a  that specifically passes about 8 kHz or less is used in order to adapt to such a case. Such a configuration would pose no problem for driving the piezoelectric bimorph element  9725  using a sound signal having sampling frequency of 16 kHz. Since an impact pulse  9725   b  is generated in a high-frequency region from the piezoelectric bimorph element  9725  by dropping or other impact, the impact pulse has a higher frequency region than the above-stated range as a principal component, and it is possible to essentially cut out such a component. 
       FIG. 162  is a block view of a first modification of the one-hundred first embodiment shown in  FIG. 161 , the same reference numerals are used for the same portions as in  FIG. 161 , and a description thereof is omitted. The first modification in  FIG. 162  is provided with a tap detection unit  9742  for using the piezoelectric bimorph element  9725  as an impact input element for detecting a tap on the mobile telephone  9701 . Such a configuration was described in the twenty-seventh embodiment, which called on  FIG. 41  to  FIG. 43 . In other words, tapping (touching) any portion of the display screen or the case of the mobile telephone  9701  with a finger makes it possible to perform determinative input for a GUI operation such as a “click” of a mouse or the like in a personal computer. 
     The tap detection unit  9742  detects an impact  9725   d  of a tap by a finger via the low-pass filter  9740   a , and this is transmitted to the application processor  9739 , whereby determinative input of a GUI operation is performed. Accordingly, the low-pass filter  9740   a  allows the band of the sound signal  9725   a  and the principal frequency band of the impact  9725   d  produced by the tap of a finger to pass, and selectively cuts the impact pulse  9725   b  of dropping or the like, which is in a higher principal frequency band than the sound signals and tapping. 
       FIG. 163  is a block view of a second modification of the one-hundred first embodiment shown in  FIG. 161 , the same reference numerals are used for the same portions as in  FIG. 161  and  FIG. 162 , and a description thereof is omitted. In the second modification in  FIG. 163 , the position in which the tap detection unit  9742   a  is provided is different from the first modification of  FIG. 162 , and the impact  9725   d  of a tap by a finger is directly detected without going through the low-pass filter  9740   a . The same applied to a feature in which determinative input of a GUI operation is performed by transmitting the impact  9725   d  of a detected tap to the application processor  9739 . The  9740   a  in this case allows the band of the sound signal  9725   a  to pass in the same manner as the embodiment of  FIG. 161 , and selectively cuts the impact pulse  9725   b  of dropping or the like, which is in a higher principal frequency band than the sound signals and tapping. 
     So as to avoid errant detection of impact by collision as the tap of a finger, a tap detection unit  9742   a  in the second modification of  FIG. 163  is provided with: an intensity discrimination unit  9742   b  for discriminating the intensity of an impact from the piezoelectric bimorph element  9725 , and eliminating impacts having a predetermined intensity or greater, deeming such to be cause by dropping; and a spectrum discrimination unit  9742   c  for discriminating a difference in spectrum in a collision with a floor, a wall, or the like and an impact of tapping with a finger, and eliminating the former which have a high ratio of high-frequency components at a predetermined level or higher. 
     An advantageous example of the low-pass filter  9740   a  using the one-hundred first embodiment and the modifications thereof in  FIG. 161  to  FIG. 163  is a RC filter composed of a resistor and a capacitor or a LC filter composed of an inductance component and a capacitor. In these embodiments and modifications thereof, a low-pass filter  9740   a  is used for impact pulses  9725   b  in the high-frequency region generated by the piezoelectric bimorph element  9725  due to dropping or other impacts, but there is no limitation imposed by the above-described configuration as long as the configuration serves as backflow prevention means for preventing backflow of voltaic power produced by the impact to the piezoelectric bimorph element  9725  to the analog output amplifier  9740 . 
     In the one-hundred first embodiment and modifications thereof in  FIG. 161  to  FIG. 163 , the settings of the cartilage conduction unit and the cause of a collision to the piezoelectric bimorph element  9725  were described for only the right-side corner in the drawing, but in the same manner as the other embodiments, in actuality, the settings of the cartilage conduction unit and the cause of a collision to the piezoelectric bimorph element  9725  are advantageously applied to both left and right corners. In this case, the arrangement of the piezoelectric bimorph element  9725  may be a center part between the two corners as noted in the forty-sixth embodiment of  FIG. 69  and elsewhere, or may be a corner on one side as noted in the sixty-fourth embodiment of  FIG. 96  and elsewhere. In either case, the cause of collision can be both left and right corners. Furthermore, the one-hundred first embodiment and the modifications thereof can be applied to cases in which a piezoelectric bimorph element is arranged in both left and right corners as noted in the sixty-eighth embodiment of  FIG. 100 , and in this case, the left and right piezoelectric bimorph elements can be mutually independently controlled. Therefore, low-pass filters would be provided between the piezoelectric bimorph element and the output part of the analog output amplifier, respectively, of each corner. 
       FIG. 164  is a partially cutaway detailed circuit diagram of when the feature of the one-hundred first embodiment of  FIG. 161  has been applied to the combination circuit composed of a boosted-voltage unit and an analog output amplifier unit shown in  FIG. 155 . In other words, a majority of  FIG. 164  is the same as  FIG. 155 , the entire boosted-voltage unit and a portion of the analog output amplifier unit is therefore omitted from the drawing, the same reference numerals are used for the same portions, and a description has been omitted unless needed. 
       FIG. 164(A)  shows the case in which the low-pass filter  9740   a  of  FIG. 161  is disposed between the analog amplifier unit  7040  (corresponding to the analog output amplifier  9740  of  FIG. 161 ) and the piezoelectric bimorph element  7013  (corresponding to the piezoelectric bimorph element  9725  of  FIG. 161 ), and the low-pass filter  9740   a  is a RC filter composed of a resistor and a capacitor. It is apparent in  FIG. 164(A)  that the RC filter is disposed between a first terminal of the piezoelectric bimorph element  7013  and OUT 2 , which is the output of CH 2  of the analog amplifier unit  7040 , and between a second terminal of the piezoelectric bimorph element  7013  and OUT 3 , which is the output CH 4  of the analog amplifier unit  7040 . 
     In similar fashion,  FIG. 164(B)  shows the case in which the low-pass filter  9740   a  is a LC filter composed of an inductance component and a capacitor. It is apparent in  FIG. 164(B)  that the LC filter is disposed between a first terminal of the piezoelectric bimorph element  7013  and OUT 2 , which is the output of CH 2  of the analog amplifier unit  7040 , and between a second terminal of the piezoelectric bimorph element  7013  and OUT 3 , which is the output CH 4  of the analog amplifier unit  7040 . 
     One-Hundred Second Embodiment 
       FIG. 165  is a block view related to a one-hundred second embodiment according to an aspect of the present invention, and is configured as a cartilage conduction vibration source device for a mobile telephone. The one-hundred second embodiment has much in common with the eighty-second embodiment of  FIG. 122 , the same reference numerals are therefore used for the same portions, and a description has been omitted unless needed. The one-hundred second embodiment of  FIG. 165  differs from the eighty-second embodiment of  FIG. 122  in terms of the configuration of a digital acoustic processing circuit  9838  in a driver circuit  9803 . 
     Described more specifically, in the digital acoustic processing circuit  9838  of FIG.  165 , the digital sound signal outputted from an application processor  9839  is outputted to an external auditory meatus occlusion effect equalizer  9838   a , a broad-sense cartilage conduction equalizer  9838   b , and an air conduction equalizer  9838   c . A switching circuit  9538   d  inputs any of the outputs to the DA converter  7138   c  on the basis of an instruction from the application processor  9839 . The output of the air conduction equalizer  9838   c  is transmitted to a speaker  9851  via a switch  9851   a  on the basis of an instruction from the application processor  9839 . The switch  9851   a  is ordinarily open, but is closed when the piezoelectric bimorph element  7013  is not to be allowed to vibrate, and outputs the voice of another party during videoconferencing as well as incoming call sounds and various guidance. 
     The broad-sense cartilage conduction equalizer  9838   b  is selected in a state in which the mobile telephone is in contact with the ear cartilage when the external auditory meatus is in the unoccluded state. As previously described, strictly speaking, cartilage conduction in the broad sense is composed of cartilage-air conduction, cartilage conduction, and direct air conduction, and cartilage-air conduction and direct air conduction are essentially dominant. As a rule of thumb, cartilage-air conduction predominates in low-pitched regions, while direct air conduction predominates in high-pitched regions; at 500 Hz, substantially all conduction is cartilage-air conduction, while at 4000 Hz, substantially all conduction is direct air conduction. 
     The broad-sense cartilage conduction equalizer  9838   b  equalizes the sound signal so that vibrations are produced in the piezoelectric bimorph element  7013 , the vibrations having flat frequency characteristics of sound pressure in the external auditory meatus as a result of cartilage conduction in the broad sense as described above. When a measurement is taken of only the direct air conduction sound of the piezoelectric bimorph element  7013 , which is made to vibrate by equalization by the digital acoustic processing circuit  9838 , the direct air conduction sound has emphasized equalization in high-pitched regions. 
     Next, the air conduction equalizer  9838   c  equalizes the sound signal so that vibrations are produced in the piezoelectric bimorph element  7013 , the vibrations having flat frequency characteristics of sound pressure as a result of only a direct air conduction component. Specifically, the frequency characteristics of when sound pressure of air-conducted sound produced by the cartilage conduction unit  9824  is directly measured or of when the sound pressure inside the external auditory meatus is measured while the cartilage conduction unit  9824  is not allowed to make contact with the ear cartilage, such frequency characteristics are equalized to as to be flat. This means that equalization is carried out for evaluating that the cartilage conduction unit  9824  is functioning normally as a conventional air conduction speaker. The cartilage conduction unit  9824  is brought into contact with the ear cartilage when external auditory meatus is in the unoccluded state, in a state in which the piezoelectric bimorph element  7013  is being made to vibrate with equalization produced by the air conduction equalizer  9838   c , and when the sound pressure inside the external auditory meatus (i.e., when measured in a state of broad-sense cartilage conduction), equalization is insufficient in high-pitched regions. 
     Furthermore, the external auditory meatus occlusion effect equalizer  9838   a  equalizes the frequency characteristics of sound pressure inside the external auditory meatus when the external auditory meatus occlusion effect (same as the “earplug bone conduction effect”) is occurring. In this case, this is essentially equalization that gives consideration almost exclusively to the characteristics of cartilage conduction. In a state in which the piezoelectric bimorph element  7013  is being made to vibrate with equalization produced by the air conduction equalizer  9838   c , when the pressing force is reduced while the cartilage conduction unit  9824  is kept in contact with the ear cartilage to open the entrance to the external auditory meatus, and the sound pressure inside the external auditory meatus is measured (i.e., when measured in a state of broad-sense cartilage conduction), equalization is insufficient in high-pitched regions. 
     When the broad-sense cartilage conduction equalizer  9838   b  or the air conduction equalizer  9838   c  is being made to function, a structure in which vibrations of the electromagnetic vibrator  8225  are transmitted from the upper frame  8227  to the front panel  8201   a  and the upper edge part of the front panel  8201   a  is made to vibrate in a relatively wide surface area is advantageous as a structure for generating sufficient direct air-conducted sound from the piezoelectric bimorph element  7013 , as in the manner of the eighty-eighth embodiment shown in  FIG. 136  to  FIG. 138 . In the manner of a modification of the one-hundredth embodiment shown in  FIG. 160(A) , a configuration in which the vibration unit  9625   b  is brought to the front surface side of the upper part of the mobile telephone and arranged near the ear, and a hole  9601   b  for air-conducted sound transit is provided near the vibration unit  9625   b  is also advantageous for generating sufficient direct air-conducted sound. 
     Equalization by the external auditory meatus occlusion effect equalizer  9838   a , the broad-sense cartilage conduction equalizer  9838   b , and the air conduction equalizer  9838   c  is set, not in relation to the characteristics of the piezoelectric bimorph element  7013  alone, but so that the generation of cartilage conduction and air conduction achieve target values in a state in which these equalizers have been joined with the cartilage conduction unit  9824  (set in a corner of a mobile telephone) and incorporated into a mobile telephone. 
       FIG. 166  is a flowchart showing the function of the application processor  9839  in the one-hundred second embodiment of  FIG. 165 . To provide a description of the function of the driver circuit  9803 , the flow of  FIG. 123  illustrates an abstraction of the operation, focusing on related functions, and the application processor  9839  also contains typical mobile telephone functions and other operations not represented in the flow of  FIG. 166 . The flow of  FIG. 166  begins when a main power source of the mobile telephone is turned on; and in step S 602  an initial startup and a check of each unit function are performed and a screen display on the display unit of the mobile telephone is started. Next, in step S 604 , the functions of the cartilage conduction unit and the outgoing-talk unit of the mobile telephone are turned off, and routine advances to Step S 606 . 
     In Step S 606 , a check is performed to determine whether an air conduction test mode has been set. If an air conduction test mode setting has not been detected, the routine advances to Step S 608 , and a check is performed to determine whether a call is being carried out by the mobile telephone based on a response from another party to a call request or based on an incoming call from another party. If the mobile telephone is in a call state, the routine advances to Step S 610 , the cartilage conduction unit and the outgoing-talk unit are turned on, and the routine advances to Step S 612 . 
     In Step S 612 , a check is performed to determine whether an air conduction mode has been set, and if this mode has not been set, the routine advances to Step S 614 . In Step S 614 , a check is performed to determine whether the external auditory meatus occluding effect (earplug bone conduction effect) is present, and if such is not the case, the routine advances to Step S 616  where a waveform inversion signal of one&#39;s own voice is not applied, and the routine proceeds to step S 618 . The presence or absence of the waveform inversion signal of one&#39;s own voice has been described in Step S 52  to Step S 56  in the flow of  FIG. 10 , and a detailed description is therefor omitted. In Step S 618 , the broad-sense cartilage conduction equalizer  9838   b  is selected and the routine advances to Step S 620 . 
     On the other hand, when the external auditory meatus occluding effect has been detected in Step S 614 , the routine proceeds to Step S 622 , the waveform inversion signal of one&#39;s own voice is added, the external auditory meatus occlusion effect equalizer  9838   a  is selected in Step S 624 , and the routine proceeds to Step S 620 . When it has been detected that the air conduction mode has been set in Step S 612 , the routine proceeds to Step S 626 , the air conduction equalizer  9838   c  is selected, and the routine proceeds to Step S 620 . 
     In Step S 620 , a check is performed to determine whether a call has been cut off, and if such is not the case, the routine returns to Step S 612 , and Step S 612  to Step S 626  are repeated as long as the call has not be cut off. It is thereby possible to modify the selection of the external auditory meatus occlusion effect equalizer  9838   a , the broad-sense cartilage conduction equalizer  9838   b , and the air conduction equalizer  9838   c  in accordance with changes in conditions and settings even during a call. On the other hand, when it has been detected that a call has been cut off in Step S 620 , the routine advances to Step S 628 , the functions of the cartilage conduction unit and the outgoing-talk unit of the mobile telephone are turned off, and the routine proceeds to Step S 630 . 
     On the other hand, when it has been detected Step S 606  that the air conduction test mode has been set, the routine proceeds to Step S 632  and selects the air conduction equalizer  9838   c . Next, in Step S 634 , the cartilage conduction unit is turned on, the routine proceeds to Step S 636 , and air conduction test processing is carried out. Air conduction test processing is processing that causes sound signals of various frequencies to be automatically generated in sequence on the basis of predetermined sound source data, and causes the piezoelectric bimorph element  7013  to vibrate on the basis of the equalization of the air conduction equalizer  9838   c . Direct air conduction generated from the cartilage conduction unit is measured using a microphone or the like to thereby test whether equalization of the air conduction equalizer  9838   c  is optimal. When air conduction test processing ends, the routine proceeds to Step S 638 , the cartilage conduction unit is turned off, and the routine proceeds to Step S 630 . Also, when a call state is not detected in S 608 , the routine immediately proceeds to Step S 630 . 
     In Step S 630 , a check is performed to determine whether the main power of the mobile telephone has been turned off, and if the main power has not be turned off, the routine returns to Step S 606  and repeats Step S 606  to Step S 638  in accordance with conditions as long as it is not detected in Step S 630  that the main power has been turned off. Conversely, the flow ends when it has been detected in step S 630  that the main power has been turned off. 
     Next, the equalizer function in the digital acoustic processing circuit  9838  in the one-hundred second embodiment of  FIG. 165  and  FIG. 166  will be described using  FIG. 167 . In the same manner as  FIG. 132  in the eighty-sixth embodiment,  FIG. 167(A)  to  FIG. 167(C)  are, respectively, an image depiction of the frequency characteristics of the piezoelectric bimorph element, an image depiction of the frequency characteristics of the vibrational acceleration level of ear cartilage when the piezoelectric bimorph element has been brought into contact with ear cartilage, and an image depiction of the equalization of the drive output to the piezoelectric bimorph element. 
       FIG. 167(A)  is the same drawing as  FIG. 132(A)  and shows that the frequency characteristics of the piezoelectric bimorph element are substantially flat until about 10 kHz. Also,  FIG. 167(B)  is the same drawing as  FIG. 132(B)  and shows that the frequency characteristics of the vibrational acceleration level of ear cartilage of when the piezoelectric bimorph element has been brought into contact with ear cartilage will present a high vibrational acceleration level comparable to a bandwidth of 1 to 2 kHz, even in a bandwidth of 1 kHz or less in which the vibrations of the piezoelectric bimorph element as the vibration source are relatively weak, yet will present a reduced vibrational acceleration level from about 3 kHz to a high-frequency bandwidth. 
     In contrast, in the image depiction of the equalization of the drive output of the piezoelectric bimorph element of  FIG. 167(C) , the image of the change in gain produced by the frequency of the external auditory meatus occlusion effect equalizer  9838   a  is indicated by a broken line, the image of the change in gain produced by the frequency of the broad-sense cartilage conduction equalizer  9838   b  is indicated by a solid line, and the image of the change in gain produced by the frequency of the air conduction equalizer  9838   c  is shown by the dot-dash line. 
       FIG. 167(D)  shows an image of the sound pressure measured when equalization is carried out by the external auditory meatus occlusion effect equalizer  9838   a  shown by the broken line in  FIG. 167(C) . As shown by the broken line in  FIG. 167(D) , the sound pressure is substantially flat, as intended, inside the external auditory meatus while measured with the entrance of the external auditory meatus in an occluded state. In contrast, in this equalization, the sound pressure inside the external auditory meatus while measured with the entrance of the external auditory meatus in an unoccluded state is excessive in the high range measured outside of the ear, as shown by the solid line in  FIG. 167(D) . Also, in this equalization, the sound pressure of only direct air conduction while measured outside of the ear is even more excessive in the high range, as shown by the dot-dash line in  FIG. 167(D) . 
       FIG. 167(E)  shows an image of the sound pressure measured when equalization is carried out by the broad-sense cartilage conduction equalizer  9838   b  indicated by the solid line in  FIG. 167(C) . As shown by the solid line in  FIG. 167(E) , the sound pressure is substantially flat, as intended, inside the external auditory meatus while measured with the entrance of the external auditory meatus in an unoccluded state. In contrast, in this equalization, the sound pressure inside the external auditory meatus while measured with the entrance of the external auditory meatus in an occluded state is insufficient in the high range, as shown by the broken line in  FIG. 167(E) . In contrast, in this equalization, the sound pressure of only direct air conduction measured outside of the ear is excessive in the high range, as shown by the dot-dash line in  FIG. 167(E) . 
       FIG. 167(F)  shows an image of the sound pressure measured when equalization is carried out by the air conduction equalizer  9838   c  indicated by the dot-dash line in  FIG. 167(C) . As shown by the dot-dash line in  FIG. 167(F) , the sound pressure is substantially flat, as intended, for direction air conduction while measured outside the ear. In contrast, in this equalization, the sound pressure inside the external auditory meatus while measured with the entrance of the external auditory meatus in an unoccluded state is insufficient in the high range, as shown by the solid line in  FIG. 167(F) . Also, in this equalization, the sound pressure of inside the external auditory meatus while measured with the entrance of the external auditory meatus in an occluded state is even more insufficient in the high range, as shown by the dot-dash line in  FIG. 167(F) . 
     The graph shown in  FIG. 167  conceptually shows a general trend in order to avoid complexity and facilitate understanding. In actuality, narrow areas of insufficient and excessive sound pressure occur in relation to equalization based on middle-range and low-range portions in the call frequency bandwidth of a mobile telephone. However, since such narrow areas of insufficient and excessive sound pressure occur when equalization is carried out using either state as a reference, there is no meaning to restricting the frequency characteristics of equalization being used as a reference, and performing equalization in accordance with a general trend as shown in  FIG. 167  is being realistic. 
     As noted above, the measurement values of  FIG. 167(D)  to (F) are not characteristics based on the vibrations of the piezoelectric bimorph element  7013  alone, but are the result of measuring the state in which cartilage conduction and air conduction are generated with the piezoelectric bimorph element  7013  joined to the cartilage conduction unit  9824  and incorporated into a mobile telephone. Therefore, the gain setting in  FIG. 167(C)  is set with the goal of obtaining measurement values of  FIG. 167(D)  to (F) in a state in which the piezoelectric bimorph element  7013  has been joined to the cartilage conduction unit  9824  and incorporated in a mobile telephone. 
     The region in which the intended flat sound pressure in  FIG. 167(D)  to (F) is to be obtained is at least 300 Hz to 3.4 kHz when the sampling frequency is 8 kHz. The range is at least 300 Hz to 7 kHz when the sampling frequency is 16 kHz. 
     Implementation of the features of the present invention described above is not limited to the aspects in the embodiments described above, and the features can be implemented in other embodiments as well, wherever it is possible to benefit from the advantages thereof. For example, in the one-hundred second embodiment of  FIG. 165 , the speaker  9851  and the piezoelectric bimorph element  7013  of when the air conduction equalizer  9838   c  has been selected assume the frequency characteristics of an air-conduction speaker, and dual use is therefore made of the air conduction equalizer  9838   c . However, the piezoelectric bimorph element  7013  and the speaker  9851  have different structures, and when the frequency characteristics are to be obtained for an optimal air conduction speaker, a dedicated equalizer may be used for the speaker  9851  without making dual use of the air conduction equalizer  9838   c.    
     One-Hundred Third Embodiment 
       FIG. 168  is a perspective view and a cross-sectional view of a one-hundred third embodiment according to an aspect of the present invention, and is configured as a mobile telephone  9901 . The one-hundred third embodiment has much in common with the eighty-eighth embodiment; therefore the same reference numerals are used for the corresponding portions and a description thereof is omitted unless required. The internal configuration of the mobile telephone  9901  can be understood by using, e.g., the fifty-fifth embodiment of  FIG. 84  and other embodiments, and a description thereof is omitted. The one-hundred third embodiment of  FIG. 168  is different from the eighty-eighth embodiment of  FIG. 136  in that an electromagnetic air-conduction speaker  9925  is dually used as a cartilage conduction vibration source. In the eighty-eighth embodiment of  FIG. 136  as well, the configuration is such that the electromagnetic vibrator  8225  serving as a cartilage conduction vibration source causes the upper edge part of the front panel  8201   a  to vibrate over a relatively wide surface area, and an air-conducted sound at a required level can be generated in an ordinary mobile telephone; and the configuration is such that both cartilage conduction and air-conducted sound can be generated. Conversely, in the one-hundred third embodiment of  FIG. 168 , first, the configuration is such that an ordinary mobile telephone can be caused to generate an air-conducted sound at a predetermined level using an electromagnetic air-conduction speaker  9925 , and the configuration is such that the vibrations thereof are also used and transmitted to the cartilage conduction units  8224  and  8226 , whereby both cartilage conduction and generation of air-conducted sound are made possible. 
     Describing the one-hundred third embodiment more specifically on the basis of  FIG. 168 , the front panel  8201   a  is provided with a hole  9901   b  for air-conducted sound transit from the electromagnetic air-conduction speaker  9925 , thus constituting an ordinary incoming-talk unit, as shown in  FIG. 168(A) . It is apparent in  FIG. 168(B) , which is a view along the cross section B 1 -B 1  of  FIG. 168(A) , that a hanging part  8227   a  is provided to the center part on the inner side of the upper frame  8227 , and this constitutes a seating for providing the electromagnetic air-conduction speaker  9925 . In order for the electromagnetic air-conduction speaker  9925  to generate an air-conducted sound, the counteraction of the vibrations reactions are transmitted to the upper frame  8227  and the cartilage conduction units  8224  and  8226  are made to vibrate. 
     In  FIG. 168(C) , which is a top view of  FIG. 168(A) , the hanging part  8227   a  on the inside and the electromagnetic air-conduction speaker  9925  provided therewith as a seating are indicated by a broken line. The electromagnetic air-conduction speaker  9925  is not in contact with any component other than the hanging part  8227   a , and the counteraction of the vibrations thereof are thereby transmitted to only the upper frame  8227  via the hanging part  8227   a . In  FIG. 168(C) , the hole  9901   b  for air-conducted sound transit provided in front of the electromagnetic air-conduction speaker  9925  in the front panel  8201   a  is also illustrated by a broken line. 
       FIG. 168(D) , which is a view along the cross section B 2 -B 2  shown in  FIG. 168(A)  to  FIG. 168(C) , shows that the hanging part  8227   a  is integrally formed with the upper frame  8227 , and that the electromagnetic air-conduction speaker  9925  is provided using the hanging part  8227   a  as a seating. The hole  9901   b  for air-conducted sound transit is shown to be provided to the front panel  8201   a  in a location in front of the electromagnetic air-conduction speaker  9925 . Furthermore, it is apparent in  FIG. 168D  as well that the electromagnetic air-conduction speaker  9925  is not in contact with any component other than the hanging part  8227   a.    
       FIG. 168(E)  is a view along the cross section B 3 -B 3  shown in  FIG. 168(B) , and illustrates the hanging part  8227   a  inside, the electromagnetic air-conduction speaker  9925  provided therewith as a seating, and a hole  9901   b  for air-conducted sound transit provided to the front panel  8201   a  in a location in front of the electromagnetic air-conduction speaker  9925 . 
       FIG. 169  is an enlarged cross-sectional view of the principal elements of the one-hundred third embodiment shown in  FIG. 168(D) , and shows the internal structure and holding structure of the electromagnetic air-conduction speaker  9925 .  FIG. 169  has much in common with the forty-eighth embodiment of  FIG. 73 ; therefore the same reference numerals are used for the corresponding portions and a description thereof is omitted unless required. The electromagnetic air-conduction speaker  9925  in one-hundred third embodiment of  FIG. 169  is different from the electromagnetic vibrating element  4324   a  in the forty-eighth embodiment of  FIG. 73  in that, firstly, the structure is configured so as to function as an electromagnetic air-conduction speaker in the manner described above, and the counteraction of the vibrations are used for cartilage conduction. 
     The internal structure and holding structure of the electromagnetic air-conduction speaker  9925  in the one-hundred third embodiment is described in detail below with reference to  FIG. 169 . The electromagnetic air-conduction speaker  9925  is largely divided into two portions. First, as the first portion, a yoke  4324   h  for holding a magnet  4324   f  and a central magnetic pole  4324   g  is anchored to and supported by the hanging part  8227   a . A top plate  4324   j , which has a gap, is anchored to this structure. 
     On the other hand, as the second portion, a voice coil  4324   m  is wrapped around a voice coil bobbin anchored to a vibration plate  9924 , and penetrates into the gap of the top plate  4324   j . A weight ring  9924   n  for increasing the inertia of the vibration plate  9924   k  overall is provided around the vibration plate  9924   k . The integral structure of the second portion contains the vibration plate  9924   k , the voice coil bobbin anchored thereto, the voice coil  4324   m , and the weight ring  9924   n , and is connected in a state suspended midair to the yoke  4324   h  of the first portion by a damper  9924   i  In this a configuration, when an audio signal is inputted into the voice coil  4323   m , relative movement occurs between the first portion composed of the yoke  4324   h  and the like and the second portion composed of the vibration plate  9924   k  and the like; the vibration plate  9924   k  thereby vibrates and an air-conducted sound is generative by way of the hole  9901   b  for air-conducted sound transit. On the other hand, the first portion composed of the yoke  4324   h  also vibrates due to the counteraction of the vibrations of the second portion composed of the vibration plate  9924   k  and the like, and these vibrations are transmitted from the upper frame  8227  to the cartilage conduction units  8224  and  8226  via the hanging part  8227   a . In the manner described above, using the counteraction of the vibrations of the electromagnetic air-conduction speaker  9925  for generating air-conducted sound as the vibration source for cartilage conduction is a configuration that allows both cartilage conduction and the generation of air-conducted sound. 
     One-Hundred Fourth Embodiment 
       FIG. 170  is a perspective view and a cross-sectional view of a one-hundred fourth embodiment according to an aspect of the present invention, and is configured as a mobile telephone  10001 . The one-hundred fourth embodiment has much in common with the sixty-fifth embodiment of  FIG. 97 ; therefore the same reference numerals are used for the corresponding portions and a description thereof is omitted unless required. The internal configuration of the mobile telephone  10001  can be understood by using, e.g., the fifty-fifth embodiment of  FIG. 84  and other embodiments, and a description thereof is omitted. The one-hundred fourth embodiment of  FIG. 170  differs from the sixty-fifth embodiment of  FIG. 97  in that the piezoelectric bimorph element  2525  is configured as an air conduction speaker and is dually used also as a cartilage conduction vibration source. In other words, the approach used in one-hundred third embodiment of  FIG. 169  can also be applied to the case of an air conduction speaker. 
     Describing the one-hundred fourth embodiment more specifically on the basis of  FIG. 170 , a hole  10001   b  for air-conducted sound transit is provided to the upper part of the front surface of the mobile telephone  10001 , as shown in  FIG. 170(A) . This is the same as the one-hundred third embodiment of  FIG. 169 . It is apparent from  FIG. 170(B) , which is a view along the cross section B 1 -B 1  of  FIG. 170(A) , one end  2525   c  of the piezoelectric bimorph element  2525  is held by the right-ear cartilage conduction unit  6124 . As a result, the other end  2525   b  of the piezoelectric bimorph element  2525  is a free vibration end, yet a vibration plate  10024   k  for efficiently generating air-conducted sound is attached thereto. In  FIG. 170(B) , the hole  10001   b  for air-conducted sound transit shown in  FIG. 170(A)  is illustrated by an imaginary line for reference in order to understand the positional relationship. Thus, the vibration plate  10024   k  vibrates in the vicinity inside the hole  10001   b  for air-conducted sound transit. On the other hand, the one end  2525   c  of the piezoelectric bimorph element  2525  is held by the right-ear cartilage conduction unit  6124  as described above, and the right-ear cartilage conduction unit  6124  therefore vibrates in good fashion due to the counteraction of the vibrations of the free end. Vibrations of the right-ear cartilage conduction unit  6124  are furthermore transmitted to the left-ear cartilage conduction unit  6126  as well by way of the linking unit  6127 . These points are the same as the sixty-fifth embodiment shown in  FIG. 97 . In the one-hundred fourth embodiment of  FIG. 170  as well, the above-described structure supports the air conduction speakers using the cartilage conduction structure in the same manner as the one-hundred third embodiment of  FIG. 168 , whereby the counteraction of the vibrations of the air conduction speaker for generating air-conducted sound is used as a cartilage conduction vibration source. The piezoelectric bimorph element  2525  is supported by the cartilage conduction unit alone as described above and does not contact the other constituent elements of the mobile telephone  10001 , so the vibrations thereof are transmitted only to the cartilage conduction unit. 
     In  FIG. 170(C) , which is a top view of  FIG. 170(A) , the vibration plate  10024   k  attached to the free vibration end  2525   b  of the piezoelectric bimorph element  2525  and the hole  10001   b  for air-conducted sound transit are illustrated by an imaginary line. In  FIG. 170(D) , which is a view along the cross section B 2 -B 2  shown in  FIG. 170(A)  to  FIG. 170(C) , the vibration plate  10024   k  is illustrated by an imaginary line for reference in order to show the positional relationship with the piezoelectric bimorph element  2525 . It is apparent from  FIG. 170(C)  and  FIG. 170(D)  that the piezoelectric bimorph element  2525  is arranged nearer to the front surface side of the mobile telephone  10001  than the sixty-fifth embodiment of  FIG. 97  so that the vibration plate  10024   k  can vibrate in the vicinity inside the hole  10001   b  for air-conducted sound transit. In  FIG. 170(D) , reference illustration of the hole  10001   b  for air-conducted sound transit is omitted in order to avoid drawing complexity. 
     The various features of each of the present invention described above are not limited to the above embodiments, and may be implements in other embodiments. For example, in  FIG. 160(A)  shown as a cross-sectional view for describing the configuration for mass production of the piezoelectric bimorph module in the one-hundredth embodiment, a design is illustrated in which the hole  9601   b  for air-conducted sound transit is provided near the vibration unit  9625   b . Also, in the structure of  FIG. 160(A) , the support parts  9697   c  and  9697   d  of the metal plate  9697 , which are at both ends of the piezoelectric bimorph module  9625 , are supported by the inner side of the elastic body units  4263   a ,  4263   b , and since there is not contact with the other constituent elements of the mobile telephone  9601 , the vibrations thereof are transmitted only to the cartilage conduction unit. Therefore, a structure such as that of  FIG. 160(A)  may be considered to be a modification of the one-hundred third embodiment shown in  FIG. 168  or the one-hundred fourth embodiment shown in  FIG. 170 . In the structure of  FIG. 160(A) , the width of the metal plate  9697  to the rear of the hole  9601   b  for air-conducted sound transit may be increased and the surface area for functioning as a vibration plate for generating air-conducted sound may be increased, provided that space allows, in order to more efficiently generate air-conducted sound that passes through the mobile telephone  9601 . 
     One-Hundred Fifth Embodiment 
       FIG. 171  is a block view related to a one-hundred fifth embodiment according to an aspect of the present invention, and is configured as a system composed of a mobile telephone  11001  and a stereo headset  11081   a ,  11081   b  capable of short-range communication therewith. The left headset  11081   a  and the right headset  11081   b , which are a stereo headset, can be constantly worn on the left and right ears. In other words, the stereo headset  11081   a ,  11081   b  in the one-hundred fifth embodiment has a configuration in which the ear hole  232  can be used in an unoccluded state in the manner of the eighty-ninth embodiment of  FIG. 139  to the ninety-second embodiment, the ninety-eighth embodiment, and the ninety-ninth embodiment of  FIG. 142 ,  FIG. 153 , and  FIG. 156 , and noise of the external environment does not become difficult to hear in comparison with an unworn state, even when the system is constantly worn on both ears as a stereo headset. Therefore, for example, there is no increase of danger in not hearing a vehicle horn or the like, and it is possible to enjoy conversation with people nearby while wearing the stereo headset. 
     The a block view of the one-hundred fifth embodiment of  FIG. 171  has much in common with the eighty-seventh embodiment of  FIG. 135 ; therefore the same reference numerals are used for the corresponding portions and a description thereof is omitted unless required. For simplification, the internal configuration of the, e.g., telephone function unit  45  is omitted from the drawing in  FIG. 171 . The internal structure of the right headset  11081   b  is omitted for simplification. Other than lacking a call microphone  11023 , the configuration is that same as the left headset  11081   a.    
     The one-hundred fifth embodiment of  FIG. 171  differs from the eighty-seventh embodiment of  FIG. 135  in that consideration is given to music enjoyment as a purpose for constantly wearing the stereo headset  11081   a ,  11081   b , and adaptation to various conditions brought about by use with the ear hole  232  in an unoccluded state. First, a digital music player unit  11084  is provided in the mobile telephone  11001  side, and output is possible from an external earphone jack  11046  via an audio input/output unit  11040 . The audio input/output unit  11040  is capable of outputting a call audio signal from the telephone function unit  45  and song signals from the music player unit  11084 , from a wireless short-range communication unit  1446  to the left headset  11081   a  and the right headset  11081   b.    
     An equalizer  11036  of the audio input/output unit  11040  performs cartilage conduction equalization adapted for driving the cartilage conduction vibration unit  1626  or the like in the left headset  11081   a  and the right headset  11081   b  by control carried out by a control unit  11039  when a call audio signal from the telephone function unit  45  is outputted from the short-range communication unit  1446 . On the other hand, when a song signal from the music player unit  11084  is outputted from the short-range communication unit  1446  to the left headset  11081   a  and the right headset  11081   b , the equalizer  11036  of the audio input/output unit  11040  increases the contribution of the air conduction component over cartilage conduction equalization by control carried out by a control unit  11039 , and high-pitched regions required for music enjoyment is supplemented by direct air-conducted sound from the cartilage conduction vibration unit  1626  or the like. 
     The equalizer  11036  of the audio input/output unit  11040  furthermore monitors the magnitude of variation (e.g., variation in intensity of sound between fortissimo and pianissimo) in the audio signal of a song in progress in the output from the music player unit  11084 , and when the audio signal falls to a predetermined level or lower (the intensity of the sound in the song migrates to the piano side), equalization is varied temporarily in accordance with the progress of the song so that the cartilage conduction component become relatively greater in the mixture ratio between the cartilage conduction component and the direct air conduction component. 
     The above-described control is significant in two ways. The first is a countermeasure to noise of a fixed intensity that does not vary in magnitude in terms of the audio signal in a song. This noise is inconspicuous in the forte (fortissimo) region of a song, but is conspicuous in the piano (pianissimo) region. Therefore, the mixture ratio of the air conduction component is increased in the forte region to achieve good music quality, the cartilage conduction component, which is good in the low-pitched regions, is used in the piano region, and the cartilage conduction component is increased in a relative fashion. 
     The second is a countermeasure to variation in the frequency characteristics of hearing in relation to the magnitude of sound. In terms of the variation in the frequency characteristics of hearing, it is known that audibility in the low-pitched regions worsens in commensurate fashion to lower magnitude sound, as indicated by, e.g., the “Fletcher and Munson equal-loudness curve.” However, as described above, the air conduction component is increased in a relative manner in the forte region and the cartilage conduction component is increased in the piano region, whereby the cartilage conduction component, which is good in the low-pitched regions, is increased in the piano region to offset a reduction in audibility. 
     The audio input/output unit  11040  outputs an incoming-call melody or other incoming-call sound to the left headset  11081   a  and the right headset  11081   b  in alternating fashion, e.g., every second when an incoming-call sound from the telephone function unit  45  is outputted from the short-range communication unit  1446  by control carried out by the control unit  11039 . An incoming-call sound is thereby easy to perceive because the incoming-call sound can be hear in alternating fashion from the left and right every second, even when the incoming-call sound is superimposed on the song being enjoyed. The incoming-call sound may be superimposed on the signal of the song being enjoyed, but it is also possible to mute the song signal to the headset on the side outputting the incoming-call sound. In this case, the incoming-call sound and the song signal can be heard in alternating fashion every second from the left and right headsets. 
     In the further case that a call sound signal from the telephone function unit  45  is to be outputted from the short-range communication unit  1446  and a three-party call is initiated, control is carried out by the control unit  11039  to, e.g., send the voice of a first party to the left headset  11081   a  and send the voice of the second party to the right headset  11081   b . The voice of two other people can thereby be separately heard from the left and right ears. The details of the various functions of the mobile telephone  11001  side noted above are later described. 
     On the other hand, the left headset  11081   a  has a passive mode and an independent mode. In the passive mode, the sound in an equalized state as received by the short-range communication unit  1487   a  is sent to the mixer unit  1636  and the cartilage conduction vibration unit  1626  is driven. In this case, the equalizer  8238  essentially does not perform any action. In independent mode, the equalizer  8238  ordinarily performs cartilage conduction equalization by control carried out by a control unit  11039   a . When the control unit  11039   a  has detected that the sound signal received by the short-range communication unit  1487   a  is music, the equalizer  8238  performs equalization for increasing the contribution of the air conduction component over that used during cartilage conduction equalization, and the signal is sent to the mixer unit  1636  to thereby drive the cartilage conduction vibration unit  1626 . The call microphone  11023  has directivity centered about the direction of the mouth of the wearer of the left headset  11081   a , the audio of the wearer is picked up and sent from the short-range communication unit  1487   a  to the mobile telephone  11001  and is then passed onto to the telephone function unit  45 . 
     An ambient sound microphone  11038  in the left headset  11081   a  has wide-angle directivity centered about the direction incoming to the ear of the wearer. Noise in the area picked up by such an ambient sound microphone  11038  is inverted by a waveform inverter  1640  and inputted to the mixer unit  1636 . In addition to a song signal for enjoyment, a vibration component in which noise in the area has been waveform-inverted is thereby generated in the cartilage conduction vibration unit  1626 . This vibration component arrives at the tympanic membrane by cartilage conduction and air-conducted sound and offsets noise in the area that has arrived by direct air conduction at the tympanic membrane. It is thereby possible to prevent music or the like being enjoyed from being difficult to hear due to noise in the area which may possibly arrive at the tympanic membrane because the system is used with the ear hole in an unoccluded state. 
     However, when such offsetting of ambient sound in the area is constantly carried out, the significance of using a configuration in which the ear hole is left in an unoccluded state to be able hear external sounds is reduced by half. Therefore, in the one-hundred fifth embodiment, offsetting of ambient sound described above is stopped by control carried out by the control unit  11039   a  when either of the following conditions has occurred. The first condition occurs when the ambience sound picked up by the ambient sound microphone  11038  has rapidly increased, and at this time, offsetting of ambient sound is stopped. This is designed to ensure that there is no danger in which, e.g., vehicle horns, and other emergency sounds in the area go unheard. The second condition occurs when a human voice at a predetermined volume level or higher has been detected by the ambient sound microphone  11038 , and at this time, offsetting of ambient sound is stopped. This is designed to ensure that, e.g., conversation with people in the area can be enjoyed and smooth communication can take place while the stereo headset is being worn and music or the like is being enjoyed. However, in relation to the second condition, excluding cases in which an incoming-call sound is being received or the mobile telephone  11001  has a call in progress, offsetting of ambient sound is continued in such cases. This is done with the idea of obtaining understanding of people in the area when a suitable response is not made to initiation of conversation from people in the area under such conditions, and priority is given to avoiding call obstruction and situations in which the user is unaware of an incoming call to the mobile telephone  11001 . 
     In the one-hundred fifth embodiment of  FIG. 171 , the configuration is such that the left headset  11081   a  and the right headset  11081   b  each receive audio signals from the mobile telephone  11001 , and the processing described above is carried out independently in the respective control units  11039   a  (the drawing of which is omitted in the right headset  11081   b ). Therefore, the right headset  11081   b  can be understood in accordance with the left headset  11081   a , and a description thereof is omitted. The details of the various functions of the left headset  11081   a  side noted above are later described. 
       FIG. 172  is an expanded system block view of the one-hundred fifth embodiment of  FIG. 171 . The mobile telephone and the left and right stereo headset are essentially the same as in  FIG. 171 , and therefore, the same reference numerals are used and a drawing of the internal configuration of the mobile telephone  11001  is omitted. Also, in relation to the headset in  FIG. 172 , the block names are left first headset  11081   a  and right first headset  11081   b  in order to distinguish from other later-described stereo headsets. 
     In the expanded system shown in  FIG. 172 , a dedicated mobile music player  11084   b  having a short-range communication unit  1446   b  is added. The left headset  11081   a  and the right headset  11081   b  are capable of intercommunication in the same manner as  FIG. 171 , are capable of receiving song signals from the mobile music player  11084   b , and perform the operations described in  FIG. 171 , including processing of song signals from the mobile music player  11084   b , when an incoming-call signal is received from the mobile telephone  11001  or a call is started while enjoying music. When the mobile music player  11084   b  is in an ordinary configuration, the left first headset  11081   a  and the right first headset  11081   b  are in independent mode, and the equalizer  8238  is mainly operating. In a system such as  FIG. 172 , when the left first headset  11081   a  and the right first headset  11081   b  are in independent mode, a system configuration is possible even when the mobile telephone  11001  is an ordinary mobile telephone that does not have a cartilage conduction equalization function. When the mobile music player  11084   b  has the same equalizer  11036  and control unit  11039  thereof for cartilage conduction as in the mobile telephone  11001 , the left first headset  11081   a  and the right first headset  11081   b  function in the passive mode. 
     A call/sound source server  11084   c  having a short-range communication unit  1446   c  is furthermore added to the expanded system in  FIG. 172 . The left first headset  11081   a  and the right first headset  11081   b  are capable of intercommunication with the mobile telephone  11001  and the mobile music player  11084   b , and are capable of communicating with the call/sound source server  11084   c  as well. When communicating with such a call/sound source server  11084   c , the left first headset  11081   a  and the right first headset  11081   b  are in the independent mode and the equalizer  8238  is mainly operating. The call/sound source server  11084   c  has the same telephone call functions and music playback functions are that in the mobile telephone  11001 , and when provided with the equalizer  11036  and the control unit  11039  thereof for cartilage conduction, the left first headset  11081   a  and the right first headset  11081   b  function in passive mode. 
     The call/sound source server  11084   c  is capable of distributing call, music, and other sound sources to a plurality of headsets within short-range communication distance, and as an example thereof, a left second headset  11081   c  and the right second headset  11081   d  capable of communication with the short-range communication unit  1446   c  are illustrated in  FIG. 172 . The details of the configuration of the left second headset  11081   c  and the right second headset  11081   d  are the same as those of the left first headset  11081   a  and the right first headset  11081   b , and a description is therefor omitted. 
       FIG. 173  is a flowchart of the operation of the control unit  11039  of the mobile telephone  11001  in the one-hundred fifth embodiment of  FIG. 171 . The flow of  FIG. 173  begins when a main power source is turned on by the operation unit  9 ; and in step S 642 , an initial startup and a check of each unit function are performed. Next, in Step S 644 , a check is performed to determine whether the headset mode (a mode for outputting an audio signal of the mobile telephone  11001  to the left first headset  11081   a  and the right first headset  11081   b ) has been set, and if the headset mode has been set, the routine proceeds to Step S 646 . In Step S 646 , a check is performed to determine whether the music player is on and a music sound signal is being outputted. 
     When it has been detected that the music player is on in Step S 646 , the routine advances to Step S 648 , an instruction is issued for an equalization setting in which the air conduction component is increased over cartilage conduction equalization, and the routine proceeds to Step S 650 . Insufficiency in high-pitched regions of the frequency characteristics of cartilage conduction is thereby supplemented, and music replay approximate to the original sound is achieved. In Step S 650 , a check is performed to determine whether the music sound signal has dropped to a predetermined level or lower (the intensity of the sound in the song migrates to the piano side). If such is the case, the routine proceeds to Step S 652 , an instruction is issued for temporarily correcting equalization in which the cartilage conduction component is increased in a relative manner by a predetermined ratio, and the routine proceeds to Step S 654 . As described above, this has significance as a noise countermeasure in the region where sound is small and as a countermeasure against reduction of audibility in low-pitched regions. 
     On the other hand, when it has been detected in Step S 650  that the music sound signal has not dropped to a predetermined level or lower (the intensity of the sound in the song migrates to the forte side), the routine proceeds directly to Step S 654 , and the equalization setting in which the air conduction component was increased in Step S 648  is maintained. Supplementation of high-pitched regions by the air conduction component is carried out in the region in which the volume is high, and music replay approximate to the original sound is achieved. Also, when it has not been detected that the music player is on in Step S 646 , the routine advances to Step S 656 , an instruction for a cartilage conduction equalization setting is issued, and the routine proceeds to Step S 654 . As described below, Step S 646  to Step S 656  are repeated at high speed, and it is therefore possible to adapt to variations in the magnitude of the sound between the forte side and the piano side midway through a song. 
     For simplification, Step S 650  to Step S 652  above have a single criterion for determining the predetermined level and variation of equalization has two stages depending on whether the cartilage conduction component is to be increased by a predetermined ratio or not. In actuality, the configuration is such that judgment level and the increase ratio of the cartilage conduction component have a plurality of stages, or that variation is continuous without any stages. In this case, variation in equalization is carried out using a table for determining the judgment level and the increase ratio of the cartilage conduction component. However, the data in the table is obtained by combining two types of tables, which are prepared in accordance with the significance of noise countermeasures having the fixed intensity noted above and in accordance with “Fletcher and Munson equal-loudness curves,” and ultimate change in equalization is determined thereby. 
     In Step S 654 , a check is performed to determine whether there has been an incoming call to the mobile telephone. If there is an incoming call, the routine proceeds to Step S 658  and an incoming-call sound is generated. If music is playing at this time, the incoming-call sound is superimposed on the music sound signal. As described above, in lieu of such superimposition, the song signal may be muted while the incoming-call sound is being generated. Next, processing is carried out for causing only the incoming-call sound to be outputted in alternating fashion every predetermined length of time (e.g., one second) to the left second headset  11081   c  and the right first headset  11081   b . The incoming-call sound superimposed on the song being enjoyed (or alone) as described above can thereby be heard in alternating fashion from the left first headset  11081   a  and the right first headset  11081   b.    
     Next, in Step S 662 , a check is performed to determine whether an operation has been performed for initiating a call in response to an incoming call (if music is being played back, replay is also interrupted by this operation). If an operation to initiate a call has not been detected, the flow returns to Step S 658 . Step S 658  to Step S 662  are thereafter repeated as long as a call has not been initiated, and alternating output of the incoming-call sound from the left first headset  11081   a  and the right first headset  11081   b  is continued. On the other hand, when a call start operation is detected in Step S 662 , the flow proceeds to Step S 664  and cartilage conduction equalization is instructed. 
     In Step S 666 , a check is performed to determine whether there is a third-party call, and if such is the case, the routine advances to Step S 668 , and the received voices of the other two parties are separated. The routine then proceeds to Step S 670  and performs processing for distributing and outputting the separated voices to the left first headset  11081   a  and the right first headset  11081   b , and the routine proceeds to Step S 672 . The voices of the other two parties can thereby be separated and heard from the left and right ears as described above. On the other hand, when a three-party call is not confirmed in Step S 666 , the routine proceeds directly to Step S 672 . In Step S 672 , a check is performed to determine whether an operation for ending a call has been performed (if music was being played back, replay is also restarted by this operation). If the call has not ended, the routine returns to Step S 666 , and Step S 666  to Step S 672  are thereafter repeated until a call end operation is detected, and during this interval, if there is a switch between a three-party call and an ordinary two-party call, the switch is handled by the routine. On the other hand, when an operation for ending a call is detected in Step S 672 , the routine proceeds to Step S 674 . 
     On the other hand, when the headset mode is not detected in Step S 644 , the routine proceeds to Step S 676  and performs ordinary mobile telephone processing, and the routine proceeds to Step S 674 . The specific content of Step S 676  is variously described in the other embodiments, and a description is therefore omitted. When an incoming call to the telephone is not detected in Step S 654 , the routine proceeds directly to Step SS 674 . In this case, music reply is continued in the manner described below. 
     In Step S 674 , a check is performed to determine whether the main power has been turned off, and if the main power is off, the flow returns to Step S 644 . Step S 644  to Step S 676  is repeated as long as the main power is not turned off. In this repetition, Step S 644  to Step S 652  are repeated at high speed when there is no incoming call to the telephone in Step S 654  or after a call end has been detected in Step S 672 , and it is possible to handle cancellation of the headset mode and turning the music player on and off. When neither has occurred, music replay is continued, and it is possible to adapt to variations in sound magnitude between the forte side and the piano side midway through a song. On the other hand, the flow ends when the main power is detected to have been turned off in Step S 674 . 
       FIG. 174  is a flowchart of the operation of the control unit  11039   a  of the headset in the one-hundred fifth embodiment of  FIG. 171 . The flow of  FIG. 174  begins when a main power source is turned on by the operation unit  1409 ; and in step S 682  an initial startup and a check of each unit function are performed. Next, in Step S 684 , an instruction is issued to make a short-range communication connection with the mobile telephone  11001 , and the routine proceeds to Step S 686 . When a short-range communication has been established on the basis of the instruction in Step S 684 , the left second headset  11081   c  and the mobile telephone  11001  thereafter remain constantly connected as long as the main power is not turned off. In Step S 686 , a check is performed to determine whether a short-range communication has been established with the mobile telephone  11001 , and when communication has been confirmed to be established, the routine proceeds to Step S 688 . 
     In Step S 688 , the ambient sound microphone  11038  is turned on, the routine advances to Step S 690 , and an instruction is issued to subject the ambient sound picked up by the ambient sound microphone  11038  to waveform inversion and superimpose the inverted waveform on the sound signal from the mobile telephone  11001 . When the ambient sound microphone  11038  has already been turned on when the routine arrives at Step S 688 , no action is performed in this step and the routine proceeds to Step S 690 . When an instruction has already been issued to superimpose the waveform-inverted signal of the ambient sound when the routine arrives at Step S 690 , no action is performed in this step and the routine proceeds to Step S 692 . Raw ambient noise that enters the ears thereby is offset by the waveform-inverted ambient noise outputted from the cartilage conduction vibration unit  1626 . 
     Next, in Step S 692 , a check is performed to determine whether the mode is the independent mode, and if the mode is the independent mode, a check is performed to determine whether a song sound signal is being received in Step S 694 . When reception of a song sound signal is not detected, the routine advances to Step S 696 , sets the cartilage conduction equalization, and the routine arrives at Step S 698 . On the other hand, when reception of a song sound signal is not detected in Step S 694 , the routine proceeds to Step S 700 , equalization for increasing the air conduction component in a relative manner is set, and the routine arrives at Step S 698 . When the mode is not detected to be the independent mode in Step S 692 , the mode must be the passive mode, and since an equalized sound signal will be received from the mobile telephone  11001 , the routine proceeds directly to Step S 698  without performing modification of equalization on the left second headset  11081   c  side. 
     In Step S 698 , a check is performed to determine whether a rapid increase in ambient sound has been detected by the ambient sound microphone  11038 . If there has been no rapid increase in ambient sound, the routine advances to Step S 702 , and a check is performed to determine whether an incoming-call sound is being received from the mobile telephone  11001 . If an incoming-call sound is not being received, the routine advances to Step S 704 , a check is performed to determine whether a call is in progress, and if a call is not in progress, the routine arrives at Step S 706 . That the routine has arrived at Step S 706  indicates that a song is being enjoyed or that no sound signal is being received from the mobile telephone  11001 . 
     In Step S 706 , a check is performed to determine whether a human voice at a predetermined level or higher has been detected by the ambient sound microphone  11038  with the assumption the above-described state holds true. Detection of whether the sound is a human voice is made by verifying, e.g., frequency components unique to a human voice and variation patterns in volume and pitch. When a human voice at a predetermined level or higher has been detected in Step S 706 , the routine advances to Step S 708 , an instruction is issued to stop superimposition of a waveform-inverted signal of ambient sound instructed in Step S 690 , and the routine returns to Step S 692 . If an instruction to stop superimposition of a waveform-inverted signal of ambient sound has already been issued when the routine arrives at Step S 708 , no action is performed in this step and the routine returns to Step S 692 . 
     On the other hand, when receipt of an incoming-call sound has been detected in Step S 702 , when a call is detected to be in progress in Step S 704 , or when a human voice has not been detected at a predetermined level or higher in Step S 706 , in any of these cases, the routine proceeds to Step S 710 , an instruction is issued to subject the ambient noise to waveform inversion and to superimpose the inverted waveform in the same manner as Step S 690 , and the routine proceeds to Step S 712 . When superimposition of the waveform-inverted signal of ambient sound has already been instructed when the routine arrives at Step S 710 , no action is performed in this step, and the routine proceeds to Step S 712 . Also, when it is not confirmed in Step S 686  that short-rand communication has been established, the routine proceeds directly to Step S 712 . 
     In Step S 712 , a check is performed to determine whether the main power has been turned off, and if the main power has not be turned off, the routine returns to Step S 686 . Steps S 686  to Step S 712  are thereafter repeated as long as the main power is not detected in Step S 712  to have been turned off. Modification of the independent mode and passive mode, modification of the cartilage conduction equalization setting, and modification of superimposition and stopping superimposition of the waveform-inverted signal of ambient sound are thereby carried out in accordance with variation in conditions. On the other hand, the flow ends when it has been detected in Step S 712  that the main power has been turned off. 
     The various features shown in the embodiments of the present invention are not necessarily unique to each embodiment, and the features of each embodiment can be used with modifications, as appropriate, and can be used in combination, wherever it is possible to benefit from the advantages thereof. For example, in lieu of stopping the waveform-inverted signal of ambient sound in Step S 708  in the flowchart of  FIG. 174 , it is possible to input the ambient sound (in this case, rapidly increased ambient sound or human voice) picked up by the ambient sound microphone  11038  to the mixer unit  1636  without performing waveform inversion, and to add this to the unaltered voice and then output the human voice from the cartilage conduction vibration unit  1626  as well. It is thereby possible to be more readily aware of vehicle horns, initiation of conversation from people in the area, and other situations. 
     Furthermore, in the one-hundred fifth embodiment shown in  FIG. 171  to  FIG. 174 , the configuration is such that the left headset  11081   a  and the right headset  11081   b  receive audio signals from the mobile telephone  11001 , and the above-described processing is carried out in their respective control units. However, in lieu of such a configuration of one-hundred fifth embodiment, it is also possible to use a configuration in which the left headset  11081   a  receives and sends, and performs overall control of equalization, ambient sound offsetting, and the like. In this case, the right headset  11081   b  is configured to merely receive drive signals from the left headset  11081   a  and to solely cause the cartilage conduction unit to vibrate without direct intercommunication with the mobile telephone  11001 . Also, in this case, in reverse from the description above, it is apparent that it is also possible to use a configuration in which the right headset  11081   b  receives and sends, and performs overall control; and the left headset  11081   a  is configured to merely receive drive signals and to solely cause the cartilage conduction unit to vibrate. 
     Also, in the one-hundred fifth embodiment shown in  FIG. 171  to  FIG. 174 , the ambient sound microphone  11038  is provided to the left headset  11081   a  side, and control for modification of superimposition of the waveform-inverted signal of ambient sound or stoppage thereof is carried out on the left headset  11081   a  side in order to accurately pick up ambient sound directed at the ear. However, the specific configuration of such control is not limited to the embodiments. For example, in order to simplify the configuration of the headset side, it is possible to use configuration in which the ambient sound microphone  11038  is provided to the mobile telephone  11001  side, control for modification of superimposition of the waveform-inverted signal of ambient sound or stoppage thereof is carried out on mobile telephone  11001  side, and only resulting sound signals are sent to the headset side. Such a configuration assumes that substantially all ambient sound entering the ear can be ascertained even when the ambient sound microphone  11038  is provided to the mobile telephone  11001  side. It is also possible to use a configuration in which the ambient sound microphone  11038  alone is provided to the headset  11081   a  side, and information about the picked-up sound is sent to the mobile telephone  11001  side to have control for modification of superimposition of the waveform-inverted signal of ambient sound or stoppage thereof carried out on the mobile telephone  11001  side in order to accurately pick up ambient sound directed at the ear. 
     In the one-hundred fifth embodiment shown in  FIG. 171  to  FIG. 174 , a configuration was described in which the cartilage conduction vibration unit is located in the headset, but the feature in which the mixture ratio between the cartilage conduction component and the direct air conduction component is temporarily varied on the basis of the magnitude of change in the sound signal as described in, e.g., the one-hundred fifth embodiment can also be implemented in the case that the cartilage conduction vibration unit is provided to the mobile telephone (e.g., the upper corner part) as in other embodiments. 
     In the one-hundred fifth embodiment shown in  FIG. 171  to  FIG. 174 , an example was shown for varying the mixture ratio between the cartilage conduction component and the direct air conduction component in accordance with the progress of a song on the basis of the change in magnitude of the sound signal. However, this feature is not limited to such an embodiment. For example, it is also possible to use a configuration in which the mixture ratio of the cartilage conduction component and the direct air conduction component is varied in accordance with the average volume. It is furthermore possible to use a configuration in which both configurations are used, i.e. a configuration for varying the mixture ratio of the cartilage conduction component and the direct air conduction component in accordance with the average volume and a configuration for varying the mixture ratio between the cartilage conduction component and the direct air conduction component on the basis of the change in magnitude of the sound signal. 
     In the one-hundred fifth embodiment shown in  FIG. 171  to  FIG. 174 , a configuration is used in which communication between the mobile telephone  11001 , the mobile music player  11084   b , the call/sound source server  11084   c , and the headsets  11081   a  to  11081   d  is carried out by wireless short-range communication, but communication therebetween may also be carried out by wired communication using a cable or the like. 
     One-Hundred Sixth Embodiment 
       FIG. 175  is a block view related to a one-hundred sixth embodiment according to an aspect of the present invention, and is configured as a mobile telephone  12001 . The block view of one-hundred sixth embodiment in  FIG. 175  has much in common with the configuration of the eighty-sixth embodiment of  FIG. 131  and elsewhere, and therefore the same reference numerals as in  FIG. 131  are used for the same portions, and a description thereof is omitted unless particularly required. For simplification, the internal configuration of, e.g., the telephone function unit  45  and the large-screen display unit  205  is omitted from the drawing in  FIG. 175 . The drive functions of the cartilage conduction vibration unit  228  are brought together as a drive unit  12038 . Furthermore, for simplification, the configuration that does not directly relate to the description of the one-hundred sixth embodiment is omitted from the drawing. However, the one-hundred sixth embodiment may be provided with other configurations omitted from the description and omitted from the drawing in  FIG. 175 , and may be implemented in combination with the various features of other embodiments. 
     The one-hundred sixth embodiment of  FIG. 175  differs from the eighty-sixth embodiment of  FIG. 131  in that the configuration is provided with a microphone  12023  (generically referred to as a later-described first microphone  12023   a , a second microphone  12023   b , a directivity-switching unit  12023   c , and the like) capable of switching directivity is provided, and the directivity of the microphone  12023  can be switched in harmony with the cartilage conduction function and various other functions of the mobile telephone  12001 . In order to describe this difference, the microphone  223  illustrated in the block of the telephone function unit  45  in  FIG. 131  is illustrated outside the telephone function unit  45  in  FIG. 175 . A detailed description will proceed below with focus on the directivity switching of the microphone  12023 . 
     The directivity-switchable microphone  12023  in the one-hundred sixth embodiment is endowed with sharp directivity by having a first microphone  12023   a  and a second microphone  12023   b , which have no directivity, arranged in proximity at a predetermined distance from each other, and sounds from other than a target direction can be reduced using the phase difference or the like of the first microphone  12023   a  and the second microphone  12023   b  using the directivity-switching unit  12023   c . The directivity-switching unit  12023   c  varies the phase difference processing, whereby the sharpness of the directivity and the direction of directivity can be adjusted. Examples of such a directivity-switchable microphone  12023  are described in JP-A 6-30494, JP-A 2011-139462, and elsewhere. The directivity-switching unit  12023   c  of the present invention, ordinary stereo audio processing can be carried out on the basis of the output information of the first microphone  12023   a  and the second microphone  12023   b  when the directivity is to be widened by reducing or completely avoiding phase difference processing. 
     In the one-hundred sixth embodiment, the sharpness of the directivity and the direction of directivity of the microphone  12023  is automatically adjusted in coordination with the various functions of the mobile telephone  12001  using a directivity-switchable microphone  12023  such as that described above. The main information source for this automatic adjustment is the acceleration sensor  49  and various mode switching of the mobile telephone  12001 . 
       FIG. 176  is a schematic view for describing an image of the automatic adjustment of the direction of directivity and the sharpness of directivity of the directivity-switchable microphone  12023  in the one-hundred sixth embodiment of  FIG. 175 .  FIGS. 176(A)  and (B) show the manner in which the direction of directivity is automatically switched to the left and right in accordance with the tilt of the mobile telephone  12001  on the basis of the detection of gravitational acceleration by the acceleration sensor  49 .  FIG. 176(A)  shows the state in which the right-side cartilage conduction unit  12024  as viewed from the front surface is brought against the right ear  28  when the mobile telephone  12001  is held with the right hand.  FIG. 176(A)  shows the face being viewed from the side, and an outline of the mobile telephone  12001  is illustrated as an imaginary line in order to show the positional relationship between the first microphone  12023   a  and the second microphone  12023   b , which cannot be seen from the back surface. In this state, the mobile telephone  12001  is tilted right and downward as viewed from the front surface (illustrated as left downward in  FIG. 176(A)  as viewed from the back surface), and the control unit  12039  issues an instruction to the directivity-switching unit  12023   c  and automatically adjusts the directivity  12023   d  of the microphone  12023  to a rightward narrow angle (illustrated as leftward in  FIG. 176(A)  as viewed from the back surface) in accordance with the output of the acceleration sensor  49  for detecting the tilt. The directivity  12023   d  of the microphone  12023  is thereby directed toward the mouth of the user and the voice of the user of the mobile telephone  12001  is almost exclusively picked up without ambient sounds in other directions being picked up. 
     In contrast,  FIG. 176(B)  shows the state in which the left-side cartilage conduction unit  12026  as viewed from the front surface is brought against the left ear  30  when the mobile telephone  12001  is held with the left hand. In this state, the mobile telephone  12001  is tilted left and downward as viewed from the front surface, and the control unit  12039  issues an instruction to the directivity-switching unit  12023   c  and automatically adjusts the directivity  12023   e  of the microphone  12023  to a leftward narrow angle (illustrated as rightward in  FIG. 176(B)  in accordance with the output of the acceleration sensor  49  for detecting the tilt. The directivity  12023   e  of the microphone  12023  is thereby directed toward the mouth of the user and the voice of the user of the mobile telephone  12001  is almost exclusively picked up without ambient sounds in other directions being picked up. 
       FIG. 176(C)  shows a state in which the mobile telephone  12001  is being used in the videoconferencing mode. Vibration output to the left and right cartilage conduction units  12024 ,  12026  is not carried out in the videoconferencing mode, and audio is outputted from the air conduction speaker  51 . In this state, the mobile telephone  12001  is not tilted as viewed from the front surface. The control unit  12039  issues an instruction to the directivity-switching unit  12023   c  in response to the setting of the videoconferencing mode, and automatically adjusts the directivity  12023   f  of the microphone  12023  to a center narrow angle. The directivity  12023   f  of the microphone  12023  is thereby directed toward the front surface, and the voice of the user directed to the mobile telephone  12001  is almost exclusively picked up without ambient sounds in other directions being picked up. The configuration may be such that the main information source for automatic adjusting the directivity  12023   f  of the microphone  12023  to a center narrow angle using the control unit  12039  is the output of the acceleration sensor  49  for detecting that the mobile telephone  12001  is not tilted left or right, instead of the videoconferencing mode setting. Furthermore, in lieu of this configuration, it is also possible to detect the videoconferencing state by detecting that the upper part of the mobile telephone  12001  has not been brought to the ear, using a configuration which conforms to, e.g., the pair of infrared light-emitting units  19 ,  20  and the shared infrared light proximity sensor  21  described in the first embodiment of  FIG. 1 . 
       FIG. 176(D)  shows a state in which the mobile telephone  12001  is being used in the speaker mode and has been placed on a desk or the like so as to be horizontal. Vibration output to the left and right cartilage conduction units  12024 ,  12026  is not carried out in the speaker mode, and audio is outputted from the air conduction speaker  51 . Such usage is advantageous for carrying out a conference call or at other times in which a single mobile telephone  12001  is surrounded by a plurality of people. The control unit  12039  issues an instruction to the directivity-switching unit  12023   c  by detection of the state of horizontal placement based on the output of the acceleration sensor  49  and the setting of the speaker mode, and the directivity  12023   g  of the microphone  12023  is automatically adjusted to a center wide angle. The microphone  12023  is thereby set to be substantially without directivity and is capable of picking up the voices of the entire a plurality of people surrounding the desk on which the mobile telephone  12001  is placed. At this time, the directivity-switching unit  12023   c  reduces or completely avoids phase difference processing for cancelling out audio from outside the directivity range, and ordinary stereo audio processing is carried out on the basis of the output information of the first microphone  12023   a  and the second microphone  12023   b . It is thereby possible to discriminate each of the directions of the voices of the plurality of people surrounding the mobile telephone  12001 . It is also possible to assess that the mobile telephone is in the speaker mode by detecting that the upper part of the mobile telephone  12001  has not been brought to the ear by making use of a configuration that conforms to the infrared light proximity sensor  21  shown in the first embodiment of  FIG. 1 , in the same manner as detection of the videoconferencing state described above, in addition to the use of mode setting information. 
       FIG. 177  is a flowchart of the operation of the control unit  12039  of the mobile telephone  12001  in the one-hundred sixth embodiment of  FIG. 175  and  FIG. 176 . The flow of  FIG. 177  begins when a main power source is turned on, and in step S 722 , an initial startup and a check of each unit function are performed. Next, in step S 724 , the directivity of the microphone  12023  is set to a center narrow angle, and the routine proceeds to Step S 726 . In Step S 726 , a check is performed to determine whether a call operation has been performed using the mobile telephone  12001 , and there has been no operation, the routine advances to Step S 728 , and a check is performed to determine whether there has been an incoming call to the mobile telephone  12001 . If there has been an incoming call, the routine proceeds to Step S 730 . Also, when a call operation has been detected in Step S 726 , the routine proceeds to Step S 730 . 
     In Step S 730 , a check is performed to determine whether there has been a response by another party to the call operation or a call has been started by an operation to receive an incoming call, and if a call has been started, the routine proceeds to Step S 732 . Also, if a call start cannot be detected, the routine returns to Step S 726 , and thereafter Step S 726  to Step S 730  are repeated to await a call start as long as the call operation or incoming call continue. 
     When a call start is detected in Step S 730 , the routine advances to Step S 732 , a check is performed to determine whether the videoconferencing mode has been set. If there is not videoconferencing, the routine advances to Step S 734 , and a check is performed to determine whether the mode is the speaker call mode. If the mode is not the speaker mode, the routine proceeds to Step S 736 , and a check is performed to determine whether the mobile telephone  12001  is tilted to the left at a predetermined angle or greater. If a predetermined leftward tilt or greater is not detected, the routine proceeds to Step S 738 , and a check is performed to determine whether the mobile telephone  12001  is tilted to the right at a predetermined angle or greater. If a predetermined rightward tilt or greater is not detected, the routine proceeds to Step S 740 , the directivity of the microphone  12023  is set to a center narrow angle, and the routine proceeds to Step S 742 . At this time, if the directivity has been set to a center narrow angle, no action is performed in this step, and the routine proceeds to Step S 742 . In the mobile telephone  12001  which uses cartilage conduction, rather than the center part of the upper edge of the mobile telephone, the upper corner of the mobile telephone is brought to the ear. Therefore, the tilt during use is greater than that of an ordinary mobile telephone and the microphone  12023  tends to be set at a distance from the mouth. Therefore, a configuration for switching the directivity between left and right to allow for right hand use and left hand use as described above is particularly useful. 
     On the other hand, in Step S 736 , when it has been detected that the mobile telephone  12001  is tilted leftward at a predetermined angle or greater, the routine proceeds to Step S 744 , the directivity of the microphone  12023  is set to a leftward narrow angle, and the routine proceeds to Step S 742 . At this time, if the directivity has already been set to a leftward narrow angle, no action is performed in this step, and the routine proceeds to Step S 742 . In contrast, when it has been detected in Step S 738  that the mobile telephone  12001  is tilted rightward at a predetermined angle or greater, the routine proceeds to Step S 746 , the directivity of the microphone  12023  is set to a rightward narrow angle, and the routine proceeds to Step S 742 . At this time as well, if the directivity has already been set to a rightward narrow angle, no action is performed in this step, and the routine proceeds to Step S 742 . 
     When it has been detected in Step S 732  that the videoconferencing mode has been set, the routine proceeds to Step S 748 , the directivity of the microphone  12023  is set to a center narrow angle, and the routine proceeds to Step S 742 . At this time as well, if the directivity has already been set to a center narrow angle, no action is performed in this step, and the routine proceeds to Step S 742 . Furthermore, when it has been detected in Step S 734  that the speaker call mode has been set, the routine advances to Step S 750 , and a check is performed to determine whether the mobile telephone is in a state of horizontal placement on the basis of the output of the acceleration sensor  49 . If such is the case, the routine proceeds to Step S 752 , the directivity of the microphone  12023  is set to a center narrow angle, the routine advances to Step S 754 , stereo processing is instructed, and the routine proceeds to Step S 742 . At this time as well, if the directivity has already been set to a center narrow angle, no action is performed in Step S 752 , the stereo processing instruction is continued in Step S 754 , and the routine proceeds to Step S 742 . On the other hand, when a state of horizontal placement is not detected in Step S 750 , the routine proceeds to Step S 748 , the directivity of the microphone  12023  is set to a center narrow angle, and the routine proceeds to Step S 742 . At this time as well, if the directivity has already been set to a center narrow angle, no action is performed in Step S 748 , and the routine proceeds to Step S 742 . 
     In Step S 742 , a check is performed to determine whether a call end operation has been performed. If no call end operation has been performed, the routine returns to Step S 732 . Step S 732  to Step S 754  are thereafter repeated as long as no call end operation is detected in Step S 742 , and the directivity is automatically switched so as to adapt to changes in various conditions during a call. On the other hand, when a call end operation has been detected in Step S 742 , the routine proceeds to Step S 756 . When an incoming call has not been detected in Step S 728 , the state corresponds to the lack of a call operation and an incoming call, and the routine therefore proceeds to Step S 758 . In Step S 758 , processing for handing an audio input operation using the microphone  12023  is carried out, and the routine proceeds to Step S 756 . When the routine arrives at audio input-handling processing of Step S 758 , the directivity of the microphone  12023  is set to a center narrow angle in Step S 724 , and the voice of audio input instructions of the user facing the mobile telephone  12001  is therefore almost exclusively picked up without ambient sounds in other directions being picked up. 
     In Step S 756 , a check is performed to determine whether the main power of the mobile telephone  12001  has been turned off, and if the main power has not been turned off, the routine returns to Step S 724 . Step S 724  to Step S 756  are thereafter repeated as long as the main power is not detected in Step S 756  to have been turned off, and adaptation is made to changes in various conditions of the mobile telephone  12001 . In other words, the flow ends when the main power is not detected in Step S 756  to have been turned off. 
     Implementation of the features of the present invention described above is not limited to the aspects in the embodiments described above, and implementation is also possible using other aspects where it is possible to benefit from the advantages thereof. For example, the configuration for automatically switching between left and right directivity by detection of rightward tilt and leftward tilt of the mobile telephone in the one-hundred sixth embodiment, and the configuration for automatically adjusting the directivity and the direction of directivity in accordance with various conditions are not limited to mobile telephones that use cartilage conduction, and may also be used in mobile telephones which perform incoming talk using an ordinary speaker. 
     In the one-hundred sixth embodiment, assessment of left-hand use or right-hand use is detected by tilt detection carried out by the acceleration sensor, but assessment of left-hand use and right-hand use is not limited thereto. For example, it is also possible to detect whether the left corner part or the right corner part of the upper part of the mobile telephone has been brought to the ear by using a configuration the conforms to the pair of infrared light-emitting units  19 ,  20  and the shared infrared light proximity sensor  21  shown in the first embodiment of  FIG. 1 . It is furthermore possible to assess left-hand use or right-hand use by providing a contact sensor in the back surface or elsewhere of the mobile telephone, and using the fact that the contact conditions of the hand are different in the case of left-hand holding and right-hand holding. 
     One-Hundred Seventh Embodiment 
       FIG. 178  is a perspective view and cross-sectional view related to a one-hundred seventh embodiment according to an aspect of the present invention, and is configuration as a mobile telephone  13001 . The one-hundred seventh embodiment has much in common with the one-hundred third embodiment of  FIG. 168 , and therefore parts that are in common have been given like reference numerals, and a description thereof has been omitted unless there is a particular need. The internal configuration of the mobile telephone  13001  is the same as the fifty-seventh embodiment and therefore  FIG. 87  will be invoked. The one-hundred seventh embodiment of  FIG. 178  is different from the one-hundred third embodiment of  FIG. 168  in relation to the cartilage conduction vibration source; an electromagnetic air-conduction speaker  9925  is used in the one-hundred third embodiment whereas a piezoelectric bimorph element  13025  is used in the one-hundred seventh embodiment. Also, a characteristic structure that is different from the other embodiments as described below is used for supporting the piezoelectric bimorph element  13025 . In the one-hundred seventh embodiment, the piezoelectric bimorph element  13025  is strictly the vibration source of the cartilage conduction units  8224  and  8226 , which is different from the one-hundred third embodiment, and air-conducted sound is generated incidentally by vibration of the upper end part of the front panel  8201   a . Concerning this point, the one-hundred seventh embodiment of  FIG. 178  is approximate to the eighty-eighth embodiment of  FIG. 136 . 
     The one-hundred seventh embodiment is described in detail below with reference to  FIG. 178 .  FIG. 178(A)  is a perspective view showing the external appearance of the mobile telephone  13001  of the one-hundred seventh embodiment, and a hole  9901   b  for air-conducted sound transit such as in the one-hundred third embodiment of  FIG. 168  is not provided. 
     Next, the arrangement and support structure of the piezoelectric bimorph element  13025  will be described with reference to  FIG. 178(B) , which is a view along the cross section B 1 -B 1  of  FIG. 178(A) . As described above, the one-hundred seventh embodiment has the piezoelectric bimorph element  13025  as a vibration source. In terms of the support thereof, the piezoelectric bimorph element  13025  is arranged vertically at an intermediate point of the cartilage conduction units  8224  and  8226 , the upper-side end is inserted into a hanging part  8227   c  of the upper frame  8227  and is supported in a cantilever manner. The other end of the piezoelectric bimorph element  13025  on the lower side freely vibrates, and the counteraction thereof is transmitted from the hanging part  8227   c  to the cartilage conduction units  8224  and  8226 . The vibration direction thereof is the direction perpendicular to the front panel  8201   a  (the direction perpendicular to the plane of the drawing in  FIG. 178 ). 
     The internal hanging part  8227   c  and the piezoelectric bimorph element  13025  inserted therein are shown by a broken line in  FIG. 178(C) , which is a top surface view of  FIG. 178(A) . It is apparent from  FIG. 178(C)  that the hanging part  8227   c  is arranged nearer to the back panel  8201   b , and that the piezoelectric bimorph element  13025  vibrates near the back panel  8201   b  without being in contact with other components other than the hanging part  8227   c . The piezoelectric bimorph element  13025  thereby vibrates without occupying space near the front panel  8201   a  in the upper part of the mobile telephone  13001  where many members are arranged. The counteractions of the vibrations of the piezoelectric bimorph element  13025  are transmitted only to the upper frame  8227  via the hanging part  8227   c.    
       FIG. 178(D) , which is a view along the cross section B 2 -B 2  of  FIG. 178(A)  to  FIG. 178(C) , shows that the hanging part  8227   c  is integrated with the upper frame  8227 , the hanging part  8227   c  is provided near to the back panel  8201   b , and the free end of the piezoelectric bimorph element  13025  inserted therein vibrates in the direction perpendicular to the front panel  8201   a  as indicated by the arrow  13025   a . In  FIG. 168(D) , it is apparent that the free end of the piezoelectric bimorph element  13025  vibrates without being in contact with other components other than the hanging part  8227   c , and the counteractions of the vibrations thereof are transmitted only to the upper frame  8227  via the hanging part  8227   c.    
       FIG. 178(E)  is a view along the cross section B 3 -B 3  shown in  FIG. 178(B) , the internal hanging part  8227   c  and the piezoelectric bimorph element  13025  inserted therein are shown by a broken line in  FIG. 178(C) . The piezoelectric bimorph element  13025  in the one-hundred seventh embodiment vibrates without occupying space near the front panel  8201   a  in the upper part of the mobile telephone  13001  where many members are arranged, and is therefore thinly configured in the direction of vibration, as shown in  FIGS. 178(A)  to (D). Such a thin piezoelectric bimorph element  13025  is supported in a cantilever manner vertically nearer the back panel  8201   b  at an intermediate point of the cartilage conduction units  8224  and  8226 , whereby vibrations can be uniformly transmitted to the cartilage conduction unit  8224  and  8226  without greatly occupying space in the upper part of the mobile telephone  13001 . 
     The one-hundred seventh embodiment shown in  FIG. 178  is furthermore configured in view of making use of cartilage conduction in a frequency range of 4 kHz or higher. Matter that will serve as a base therefor is described below. 
     As previously described, the graph showing the measurement data of a mobile telephone in  FIG. 79  shows that when the mobile telephone is brought into contact with the ear cartilage around the entrance part of the external auditory meatus with a contact pressure of 250 gram-force (the sound pressure of normal use), the sound pressure 1 cm into the external auditory meatus from the entrance part to the external auditory meatus increases by at least 10 dB in the main frequency band (500 Hz to 2300 Hz) of speech in comparison with a non-contact state. (See a comparison of the non-contact state indicated by a solid line in  FIG. 79  and the contact state at 250 gram-force indicated by the dot-dash line.) In contrast, the difference in sound pressure between the non-contact state and the contact state at 250 gram-force becomes relatively smaller in higher frequency bands (e.g., 2300 Hz to 7 kHz). However, according to  FIG. 79 , an increase in sound pressure in the contact state at 250 gram-force in comparison with the non-contact state is readily apparent even in higher frequency bands. This circumstance is the same in a comparison of the non-contact state (solid line) and the sound pressure at a contact pressure of 500 gram-force (dot-dash line) in which the external auditory meatus is occluded, and although not as dramatic as the main frequency band (500 Hz to 2300 Hz) of speech, an increase in sound pressure in the contact state at 500 gram-force in comparison with the non-contact state is readily apparent even in higher frequency bands (e.g., 2300 Hz to 7 kHz). In particular, direct air-conducted sound is not present because the external auditory meatus is occluded in a contact pressure of 500 gram-force, and the increase in sound pressure from the non-contact state is due to cartilage conduction. 
     As previously noted, in terms of changes in the frequency characteristics of hearing, it is known that audibility in the low-pitched regions is worsened as the sound is reduced.  FIG. 179  shows this fact and is referred to as a “Fletcher and Munson equal-loudness curve.” It is apparent from  FIG. 179  that when, e.g., 100 Hz and 1 kHz are compared, equal loudness can be obtained on the equal-loudness curve of 100 phon at a sound pressure level of about 100 decibels. However, it is apparent according to the equal-loudness curve of 40 phon that 1 kHz is 40 dB, but 100 Hz is 60 dB, and in order to obtain the same loudness as 1 kHz at 100 Hz, an extra 20 db of sound pressure is required. In other words, audibility is worsened as the equal-loudness curve rises above the point that intersects the horizontal axis, and audibility is improved therebelow. It is apparent that an increase in sound pressure in the relatively low-frequency region in  FIG. 79  is advantageous in terms of supplementing a reduction in human audibility in a region in which sound is low such as in  FIG. 179 . 
     On the other hand, in a relatively high-frequency region (e.g., 4 kHz to 10 kHz) as shown in  FIG. 179 , the audibility of humans is maintained at a relatively good level even when the sound is reduced (admitting the fact that audibility is reduced from the high-frequency side due to aging). When consideration is given to such characteristics of human audibility, a sound pressure increase by cartilage conduction in the high-frequency band (e.g., 2300 Hz to 7 kHz) in accordance with the experiment results of  FIG. 79  shows that practical sound transmission is possible by cartilage conduction, not only in the main frequency band (500 Hz to 2300 Hz) of speech, but also in higher frequency regions (e.g., 4 kHz to 10 kHz). In reality, when the cartilage conduction unit is driven with a pure tone and brought into contact with ear cartilage in a state in which an earplug is used to eliminate the effect of direct air-conducted sound, it was found that sound can be satisfactorily heard by cartilage conduction at least at 7 kHz. Furthermore, in an experiment with young subjects, an increase in sound pressure is clearly heard by change from a non-contact state to a contact state, even at 10 kHz, and it was confirmed that cartilage conduction occurs even at such a frequency. 
     The one-hundred seventh embodiment shown in  FIG. 178  is configured so as to make use of cartilage conduction across the frequency region of 4 kHz and higher with acknowledgement of the above, and specifically, equalization is performed with consideration given to the characteristics of cartilage conduction in the region 300 Hz to 7 kHz. Also, when the external earphone jack  8246  is used, wide-band equalization (e.g., equalization in the region of 20 Hz to 20 kHz) is performed with consideration given to the playback of a music source. 
     The one-hundred seventh embodiment shown in  FIG. 178  expands the frequency band that makes use of cartilage conduction to 7 kHz as described above. Cartilage conduction can be used even in a frequency band of 7 kHz or higher as described above, but the reason for using a setting of 7 kHz is to give priority to protecting privacy and to reducing annoyance to the surroundings, which are advantages of cartilage conduction. Human audibility as shown in  FIG. 179  remains high in relation to still small sounds in the high-frequency band of 7 kHz or higher. On the other hand, the high-frequency band of 7 Hz or higher is a region that is heard as a raspy sound and is unpleasant to the surrounding even when the sound is small. Therefore, the piezoelectric bimorph element is not allowed to vibrate in a frequency band of this region, and unpleasant air-conducted sound is prevented from being produced in the surroundings even with a small amount of sound leakage. 
     Currently, in a call by a typical mobile telephone, a frequency band of 3.4 kHz or greater is not used, but as described above, the sampling frequency in PHS and IP telephones is 16 kHz, and can be quantized to 8 kHz. Therefore, audio signals at about 7 kHz are used. Also, broad-sense cartilage conduction in which consideration is also given to the direct air conduction component is anticipated in a mobile telephone as well in view of future improvements in the data communication rates, and in this case as well, it is believed that the piezoelectric bimorph element  13025  will be made to vibrate in a region up to about 7 kHz. In such conditions, the configuration shown in the one-hundred seventh embodiment would be very useful. 
     A detailed description is provided below, and the block view of one-hundred seventh embodiment is the same as the fifty-seventh embodiment, and  FIG. 87  will therefore be invoked. However, the functions of the application processor  5339  and the functions of the control unit  5321  for controlling the analog front end  5336  and the cartilage conduction acoustic signal processing unit  5338  by instructions from the application processor are different from those of the fifty-seventh embodiment. Specifically, in  FIG. 87 , the sound signals provided by the earphone jack  5313  (corresponding to the earphone jack  8246  in  FIG. 178 ) and the equalization of the sound signal provided to the amplifier  5340  for driving the piezoelectric bimorph element  5325  (corresponding to the piezoelectric bimorph element  13025  in  FIG. 178 ) are different from the fifty-seventh embodiment as noted above. 
       FIG. 180  is a flowchart showing the functions the application processor  5339  (which calls on  FIG. 87 ) in the one-hundred seventh embodiment. The flow of  FIG. 180  illustrates an abstraction of the operation with focus on the functions of the application processor  5339  related to control of the analog front end  5336  and the cartilage conduction acoustic signal processing unit  5338  in  FIG. 87 . The application processor  5339  also contains typical mobile telephone functions and the like not notated in the flow of  FIG. 180 . The application processor  5339  is also capable of achieving the various functions shown in other various embodiments, and these functions are omitted from the drawing and the description in  FIG. 180  in order to avoid complexity. 
     The flow of  FIG. 180  begins when a main power source of the mobile telephone  13001  is turned on; in Step S 762  an initial startup and a check of each unit function are performed and a screen display on the display unit  8205  of the mobile telephone  13001  is started. Subsequently, in Step S 764 , the function of the piezoelectric bimorph element  13025 , the amplifier  5340  and other cartilage conduction units related to the driving thereof, and the outgoing-talk unit  8223  of the mobile telephone  13001  are turned off, and the routine proceeds to Step S 766 . 
     In Step S 766 , a check is performed to determine whether an ear phone or the like has been inserted into the external earphone jack  8246 . If an insertion into the external earphone jack  8246  has been detected, the routine advances to Step S 768 , and a check is performed to determine whether there is an ongoing call state. If there is an ongoing call state, the routine advances to Step S 770 , the functions of the cartilage conduction unit and the outgoing talk unit are turned on, and the routine advances to Step S 772 . In Step S 772 , equalization is carried out with consideration given to the characteristics of cartilage conduction, in Step S 774 , equalization is carried out in the frequency band of 300 Hz to 7 kHz, and the routine proceeds to Step S 776 . The reason for dividing Step S 772  and Step S 774  is to functionally separate and describe the case in which an ear phone is inserted into the external earphone jack  8246  to perform a telephone call as later-described, and the case in which equalization is carried out in the frequency band of 300 Hz to 7 kHz without consideration given to the characteristics of cartilage conduction. In reality, when the cartilage conduction is turned on, Step S 772  and Step S 774  are executed as integrated equalization. 
     In Step S 776 , a check is performed to determine whether the entrance of the external auditory meatus is being occluded, and if not, the routine advances to Step S 778 , and the routine advances to Step S 780  without adding the waveform-inversion signal of one&#39;s own voice. The check of whether the entrance to the external auditory meatus is being occluded is made possible by processing that deems or otherwise concludes that the external auditory meatus is occluded by an ear phone by, e.g., using the output of the pressure sensor  242  described in the fourth embodiment of  FIG. 9 , or detecting that an ear phone plug has been connected to the external earphone jack  8246 . The addition or non-addition of the waveform-inversion signal of one&#39;s own voice is described in Step S 52  to Step S 56  in the flow of  FIG. 10 , so the details thereof are omitted. On the other hand, when it has been detected in Step S 776  that the entrance to the external auditory meatus is being occluded, the routine proceeds to Step S 782 , the waveform-inversion signal of one&#39;s own voice is added, and the routine proceeds to Step S 780 . 
     In Step S 780 , a check is performed to determine whether a call has been cut off, and if not, the routine returns to Step S 776 , and Step S 776  to Step S 780  are thereafter repeated as long as the call has not been cut off. The waveform-inversion signal of one&#39;s own voice can thereby be modified in response to changes in settings and conditions even during a call. On the other hand, when it has been detected in Step S 780  that a call has been cut off, the routine advances to Step S 784 , the functions of the cartilage conduction unit and the outgoing-talk unit are turned off, and the routine proceeds to Step S 786 . When an ongoing call state is not detected in Step S 768 , the routine proceeds directly to Step S 784 . If the functions of the cartilage conduction unit and the outgoing-talk unit are already in an off state when the routine arrives at Step S 784 , no action is performed in Step S 784 , and the routine proceeds to Step S 786 . 
     In contrast, when insertion into the external earphone jack  8246  has been detected in Step S 766 , the routine proceeds to Step S 788 , the cartilage conduction is turned off, and the routine proceeds to Step S 790 . If the cartilage conduction unit is already in an off state at this time, no action is performed in Step S 788 , and the routine proceeds to Step S 790 . In Step S 790 , a check is performed to determine whether there is an ongoing call state. If an ongoing call state exists, the routine advances to Step S 792 , the function of the outgoing-talk unit is turned on, and the routine advances to Step S 774 . The voice from the other party of the call outputted from the external earphone jack  8246  can thereby be heard, and the call for sending one&#39;s own voice from the outgoing-talk unit is made possible. Also, by proceeding to Step S 774 , equalization is performed in the frequency band of 300 Hz to 7 kHz, and the routine thereafter enters the same flow as used during cartilage conduction. In this case, the routine has not passed through Step S 772 , and equalization is therefore carried out in the frequency band of 300 Hz to 7 kHz without consideration given to the characteristics of cartilage conduction. In the case that Step S 776  uses a method for assessing whether to deem that the external auditory meatus to be in an occluded state using the fact that an external earphone is being used, the flow, when having arrived at Step S 776  by way of Step S 792 , almost exclusively takes a route that arrives at Step S 780  by way of Step S 776  to Step S 782 . It is thereby possible to reduce the discomfort of hearing one&#39;s own voice during earphone usage. 
     On the other hand, when an ongoing call state is not detected in Step S 790 , music data is being outputted from the external earphone jack  8246 , and therefore, wide-band equalization (e.g., 20 Hz to 20 kHz) is performed in Step S 794 , and the routine proceeds to Step S 796 . In Step S 796 , music data playback or other music enjoyment processing is carried out, and if the processing ends, the routine proceeds to Step S 786 . 
     In Step S 786 , a check is performed to determine whether the main power of the mobile telephone has been turned off, and if the main power has not been turned off, the routine returns to Step S 766 , and Step S 766  to Step S 796  is thereafter repeated in accordance with the conditions as long as the main power is not detected in Step S 786  to have been turned off. In contrast, the flow ends when the main power is detected in Step S 786  to have been turned off. 
     One-Hundred Eighth Embodiment 
       FIG. 181  is a cross-sectional view relating to a one-hundred eighth embodiment and a modification thereof according to an aspect of the present invention, and is configured as a mobile telephone  14001  or a mobile telephone  15001 . The one-hundred eighth embodiment and modification thereof has much in common with the one-hundred seventh embodiment of  FIG. 178 , and therefore parts that are in common have been given like reference numerals, and a description thereof has been omitted unless there is a particular need. There is no difference from the one-hundred seventh embodiment in terms of the external appearance, and therefore  FIG. 178(A)  shall be invoked and the illustration of the perspective view in  FIG. 181  is omitted. The one-hundred eighth embodiment of  FIG. 181  differs from the one-hundred seventh embodiment of  FIG. 178  in that the piezoelectric bimorph element  14025  or  15025  is arranged in a horizontal orientation in the one-hundred eighth embodiment and the modification thereof, whereas the piezoelectric bimorph element is arranged in a vertical orientation in the one-hundred seventh embodiment. 
       FIG. 181(A)  in the one-hundred eighth embodiment corresponds to a view along the cross section B 1 -B 1  of  FIG. 178(A)  (invoking the one-hundred seventh embodiment). It is apparent in  FIG. 181(A)  that a hanging part  8227   d  from the upper frame  8227  is provided to an intermediate point of the cartilage conduction units  8224  and  8226  in the one-hundred eighth embodiment as well. However, the piezoelectric bimorph element  14025  is arranged in a horizontal orientation, and the right-side end in the drawing is inserted into the hanging part  8227   d  and thereby supported in a cantilever state. The other lefts-side end of the piezoelectric bimorph element  14025  in the drawing freely vibrates, and the counteractions thereof are transmitted from the hanging part  8227   d  to the cartilage conduction units  8224  and  8226 . The direction of vibration is the direction perpendicular to the front panel  8201   a  (the direction perpendicular to the plane of the drawing in  FIG. 181 ) in the same manner as the one-hundred seventh embodiment. 
     The internal hanging part  8227   d  and the piezoelectric bimorph element  13025  inserted therein are shown by a broken line in  FIG. 181(B) , which corresponds to a top surface view of  FIG. 178(A)  (invoking one-hundred seventh embodiment). It is apparent from  FIG. 181(B)  that the hanging part  8227   d  is arranged nearer to the back panel  8201   b , and that the piezoelectric bimorph element  14025  vibrates near the back panel  8201   b  without being in contact with other components other than the hanging part  8227   d , in the same manner as the one-hundred seventh embodiment. The piezoelectric bimorph element  14025  thereby vibrates without occupying space near the front panel  8201   a  in the upper part of the mobile telephone  14001  where many members are arranged, in the same manner as the one-hundred seventh embodiment. In the one-hundred eighth embodiment as well, the counteractions of the vibrations of the piezoelectric bimorph element  14025  are transmitted only to the upper frame  8227  via the hanging part  8227   d.    
       FIG. 181(C) , which is a view along the cross section B 2 -B 2  shown in  FIGS. 181(A)  and (B), shows that the hanging part  8227   d  is integrated with the upper frame  8227 , and that the hanging part  8227   d  is provided near the back panel  8201   b , in the same manner as the one-hundred seventh embodiment. 
       FIG. 181(D)  to  FIG. 181(F)  show a modification of the one-hundred eighth embodiment.  FIG. 181(D)  corresponds to a view along the cross section B 1 -B 1  of  FIG. 178(A)  (invoking the one-hundred seventh embodiment), and shows that two hanging parts  8227   e  and  8227   f  hanging from the upper frame  8227  are provided at an equidistant interval from an intermediate point of the cartilage conduction units  8224  and  8226 . The piezoelectric bimorph element  15025  is arranged in a horizontal orientation in the same manner as in the one-hundred eighth embodiment, and the two hanging parts  8227   e  and  8227   f  are each inserted from inside and are supported at both ends rather than being supported in a cantilever fashion as in the one-hundred eighth embodiment. In order to achieve such a support, it is possible to use an assembled structure in which, e.g., at least one of the hanging part  8227   e  and the hanging part  8227   f  is made to be removable from the upper frame  8227 , the two ends of the piezoelectric bimorph element  15025  is inserted between the hanging parts  8227   e  and  8227   f , and the hanging parts  8227   e  and  8227   f  are thereafter integrally attached to the upper frame  8227 . In the case of such a two-end support arrangement, the center portion of the piezoelectric bimorph element  15025  vibrates freely, and the counteractions thereto are transmitted from the hanging parts  8227   e  and  8227   f  to the cartilage conduction units  8226  and  8224 , respectively. The direction of vibration is the direction perpendicular to the front panel  8201   a  (the direction perpendicular to the plane of the drawing in  FIG. 181 ) in the same manner as the one-hundred eighth embodiment. 
     The internal two hanging parts  8227   e ,  8227   f  and the piezoelectric bimorph element  15025  inserted therein are shown by a broken line in  FIG. 181(E) , which corresponds to a top surface view of  FIG. 178(A)  (invoking the one-hundred seventh embodiment). It is apparent from  FIG. 181(E)  that the two hanging parts  8227   e  and  8227   f  are arranged nearer to the back panel  8201   b  in the same manner as the one-hundred eighth embodiment, and the piezoelectric bimorph element  15025  vibration near the back panel  8201   b  without being in contact with any component other than the hanging parts  8227   e  and  8227   f . The piezoelectric bimorph element  15025  thereby vibrates without occupying space near the front panel  8201   a  in the upper part of the mobile telephone  15001  where many members are arranged, in the same manner as the one-hundred eighth embodiment. In the modification of the one-hundred eighth embodiment as well, the counteractions of the vibrations of the piezoelectric bimorph element  15025  are transmitted only to the upper frame  8227  via the hanging parts  8227   e  and  8227   f.    
       FIG. 181(F) , which is a view along the cross section B 2 -B 2  shown in  FIGS. 181(D)  and (E), shows that the hanging parts  8227   e ,  8227   f  are integrated with the upper frame  8227 , and that the hanging parts  8227   e ,  8227   f  are provided near the back panel  8201   b , in the same manner as the one-hundred seventh embodiment. In the modification, there are two hanging parts  8227   e  and  8227   f , and in  FIG. 181(F) , the cross section B 2 -B 2  corresponding to the hanging part  8227   f  portion is therefore representatively shown. 
     The various features shown in the preceding embodiments are not necessarily unique to the respective embodiments, and the features the embodiments may be combined or rearranged, as appropriate, with the features of other embodiments wherever it is possible to benefit from the advantages thereof. The specific individual configurations in the respective embodiments may also be substituted with other equivalent means. For example, in the one-hundred seventh embodiment of  FIG. 178 , the one-hundred eighth embodiment of  FIG. 181 , and the modification thereof, there is shown a configuration in which an end part of the piezoelectric bimorph element is inserted into the hole of the hanging part, but the support of the piezoelectric bimorph element is not limited to such a configuration, and it is also possible to use a configuration in which, e.g., the end part of the piezoelectric bimorph element is bonded to the hanging part. 
     Also, in the one-hundred seventh embodiment of  FIG. 178 , the configuration in which the piezoelectric bimorph element  13025  is arranged nearer to the back panel  8201   b  and is made to vibrate without occupying space near the front panel  8201   a  in the upper part of the mobile telephone  13001  where many members are arranged is not limited to the piezoelectric bimorph element being used as a cartilage conduction vibration source, but also has other usefulness. For example, when an electromagnetic vibrator is used as the cartilage conduction vibration source, the same advantages can be enjoyed by arranging the electromagnetic vibrator near the back panel. 
     Furthermore, in the present invention, the configuration in which air-conducted sound equalization is carried out across a wide band to 20 kHz for the earphone jack and cartilage conduction equalization is carried out to 7 kHz in the cartilage conduction vibration source is not limited to the use of a piezoelectric bimorph element as the cartilage conduction vibration source as shown in the one-hundred seventh embodiment of  FIG. 178 , and the configuration is useful when other cartilage conduction vibration sources are used. For example, this feature is useful when an electromagnetic vibrator is used as the cartilage conduction vibration source. 
     One-Hundred Ninth Embodiment 
       FIG. 182  is a schematic view of a one-hundred ninth embodiment according to an aspect of the present invention, and is configured as a stereo earphone.  FIG. 182(A)  is a front view (corresponding to the side surface of the face) of the right-ear earphone worn on the right ear  28 . A drawing of the face other than the right ear  28  is omitted for simplicity. Also, the stereo earphone in the present embodiment and thereafter will be described for only the right ear for simplicity, but the embodiments may be provided with a left-ear earphone having the same configuration, and the right-ear earphone and the left-ear earphone may be connected to an external output stereo mini-jack of a mobile telephone or a mobile music terminal by a stereo mini-plug. In  FIG. 182(A) , the configuration of the right-ear earphone is indicated by a broken line in order to show the relationship with the structure of the ear. 
     It is apparent in  FIG. 182(A)  that a cartilage conduction unit  16024  of the right-ear earphone is wedged into the space between the inner side of the tragus  32  and the anthelix  28   a . Also, a passage hole  16024   a  that substantially matches the entrance to the external auditory meatus  30   a  is provided to the cartilage conduction unit  16024 . The cartilage conduction unit  16024  is composed of an elastic body having strong resiliency and conforms to personal differences in the width of the wearing space between the inner side of the tragus  32  and the anthelix  28   a  by deformation of wearing, and the cartilage conduction unit  16024  is designed not to fall from the wearing space due to the resiliency that accompanies deformation. The ear cartilage itself also slightly deforms due to wearing, and the cartilage conduction unit  16024  is held by the resiliency thereof. Therefore, the cartilage conduction unit  16024  has an elastic body structure that is firmer than the ear cartilage itself. 
     A sheath  16024   b  is anchored to the cartilage conduction unit  16024 , and the piezoelectric bimorph element (not shown in  FIG. 182(A) ) is accommodated therein. The piezoelectric bimorph element is capable of vibrating so as to avoid contact with the inner wall of the sheath  16024   b  as described below, and the upper end part thereof is anchored to the cartilage conduction unit  16024 . The sheath  16024   b  is capable of being hooked on the intertragic notch  28   f  from the cavum conchae  28   e  to hang down below the ear  28 . In  FIG. 182(A) , the sheath  16024   b  is illustrated so as to be tilted down to the right and hanging in the drawing, but may also hang substantially vertically downward due to personal difference in the shape of the ear. The details of the ear structure are described in  FIG. 80 , and the manner in which the cartilage conduction unit  16024  of the earphone and the sheath  16024   b  is accommodated in the ear can therefore be better understood with reference thereto. 
       FIG. 182(B)  is a side view of the earphone and the left side in the drawing corresponds to the entrance to the external auditory meatus  30   a . Illustration of the ear is omitted for simplicity. It is apparent in  FIG. 182(B)  that the cartilage conduction unit  16024  has a greater thickness protruding in the direction of the entrance to the external auditory meatus  30   a  than does the sheath  16024   b  so as to be accommodated in the space between the inner side of the tragus  32  and the anthelix  28   a . Also, the cartilage conduction unit  16024  has a ring-like edge  16024   c  on the right side (the opposite side from the entrance to the external auditory meatus  30   a ) in the drawing around the passage hole  16024   a.    
       FIG. 182(C)  is an enlarged view of the front surface of the earphone, and shows the manner in which the ring-like edge  16024   c  is provided to the periphery of the passage hole  16024   a . It is apparent in  FIG. 182(C)  that the sheath  16024   b  is embedded in and anchored to the lower part of the cartilage conduction unit  16024 . The upper end of the piezoelectric bimorph element  16025  is furthermore direction embedded in and anchored to the lower part of the cartilage conduction unit  16024  without contact with the inner wall of the sheath  16024   b . On the other hand, the lower end of the piezoelectric bimorph element  16025  is capable of freely vibrating inside the sheath  16024   b , the counteractions thereof are transmitted to the cartilage conduction unit  16024 , and good cartilage conduction to the ear cartilage is produced. Also, a connection cable  16024   d  is drawn out from the lower end of the piezoelectric bimorph element  16025 , and this is passed through the lower end of the sheath  16024   b  and connected to a stereo mini-plug. 
       FIG. 182(D)  is a view along the cross section B 1 -B 1  of  FIG. 182(C)  and shows the manner in which the ring-like edge  16024   c  provided to the periphery of the passage hole  16024   a  protrudes to the outer side (the upper side in the drawing). The one-hundred ninth embodiment is configured so that music or the like can be enjoyed by cartilage conduction essentially without blocking external sounds by using a widely opened passage hole  16024   a . It is thereby possible to be readily aware of vehicle horns and other danger sounds when music is being enjoyed outdoors, and smooth communication can take place in immediate response to being spoken to by people in the surroundings. When there is a desire to temporarily occlude the external auditory meatus to concentration on music enjoyment, the cartilage conduction unit  16024  is lightly pressed to the ear with the body of a finger  16067  from the exterior while the earphone is being worn, as shown in  FIG. 182(D) . The contact pressure between the cartilage conduction unit  16024  and the ear cartilage is thereby increased, volume is increased, and the ring-like edge  16024   c  lightly bites into the body of the finger  16067  to efficiently occlude the passage hole  16024   a , as shown in  FIG. 182(D) . Since these are stereo earphones, it is obvious that the earphones of both ears are to be pressed in the manner described above in order to achieve an occluded state of the external auditory meatus. 
       FIGS. 182(E) , (F), and (G) show  FIG. 182(C)  in a simplified form, and show the manner in which the cartilage conduction unit  16024  deforms.  FIG. 182(F)  is a standard state,  FIG. 182(E)  shows a state in which the cartilage conduction unit  16024  is firmly pressed and deformed from the left and right when being worn by a person having narrow wearing space to the left and right between the inner side of the tragus  32  and the anthelix  28   a . On the other hand,  FIG. 182(G)  shows the state in which the cartilage conduction unit  16024  is firmly pressed and deformed from above and below when worn by a person having a narrow wearing space in the vertical direction.  FIGS. 182(E) , (F), and (G) show simplified typical examples, and the cartilage conduction unit  16024  can be freely deformed in accordance with personal differences in the shape of the wearing space. 
     One-Hundred Tenth Embodiment 
       FIG. 183  is a schematic view of a one-hundred tenth embodiment according to an aspect of the present invention, and is configured as a stereo earphone. The one-hundred tenth embodiment of  FIG. 183  has much in common with the one-hundred ninth embodiment of  FIG. 182 , and therefore the same parts have been given the same reference numerals, and a description thereof has been omitted. The one-hundred tenth embodiment differs from one-hundred ninth embodiment in that the configuration is such that a sheath  17024   b  is capable of sliding up and down with respect to a cartilage conduction unit  17024 , whereby a passage hole  17024   a  can be opened and closed. The passage hole  17024   a  is configured to be relatively small as shown in  FIG. 183(A)  in order to facilitate opening and closing. External sounds can read the tympanic membrane from the external auditory meatus even with a small gap, and there is no problem even when the passage hole  17024   a  is small. The cartilage conduction unit  17024  stably guides the sheath  17024   b  and avoids deformation, and it therefore composed of a hard material, which is different from the one-hundred tenth embodiment. In the case of the one-hundred tenth embodiment, accommodation of personal differences in the shape and size of the wearing space assumes deformation of the cartilage itself. 
       FIGS. 183(B)  and (C) are side views of an earphone and can be understood in the same manner as  FIG. 182(B) . In  FIGS. 183(B)  and (C), a piezoelectric bimorph element  17025  is noted as a broken line in order to describe the relationship with the movement of the sheath  17024   b . Also, the outer side (the right side facing the drawing) of the passage hole  17024   a  is a window  17024   e  through which the sheath  17024   b  enters and exits, and when the sheath  17024   b  is lowered, the window  17024   e  is open and is in essentially the same state as the one-hundred ninth embodiment of  FIG. 182 . On the other hand, when the sheath  17024   b  is raised in the manner of  FIG. 183(C) , the window  17024   e  is occluded, the passage hole  17024   a  is thereby blocked, and the external auditory meatus is therefore in an occluded state. Thus, in the one-hundred tenth embodiment, the sheath  17024   b  is lowered and raised to thereby allow use with the external auditory meatus in an unoccluded state and the external auditory meatus in an occluded state. Switching between the states of  FIGS. 183(B)  and (C) can also be carried out prior to wearing the earphone on the ear, but the sheath  17024   b  can be lower and raised to switch the state while the earphone is being worn. 
       FIG. 183(D)  is an enlarged view of the front surface of the earphone and corresponds to the external auditory meatus in the unoccluded state of  FIG. 183(B) . The sheath  17024   b  is configured so as to be capable of moving up and down inside the cartilage conduction unit  17024  along a guide groove  17024   f  provided to the periphery of the window  17024   e . The upper end of the piezoelectric bimorph element  17025  is directly embedded in and anchored to the lower part of the cartilage conduction unit  17024  without making contact with the inner wall of the sheath  17024   b . The lower end of the piezoelectric bimorph element  17025  is the same as in the one-hundred ninth embodiment in being capable of freely vibrating inside the sheath  17024   b . In such a configuration, the piezoelectric bimorph element  17025  is stably joined to the cartilage conduction unit  17024  and transmits the vibrations thereof even when the sheath  17024   b  is moved up or down. 
       FIG. 183(E)  is an enlarged view of the front surface of the same earphone as  FIG. 183(D) , and corresponds to the external auditory meatus in the occluded state of  FIG. 183(C) . The sheath  17024   b  slides upward along the guide groove  17024   f  and forms a state that covers the window  17024   e . The passage hole  17024   a  is also blocked thereby, as indicated by the broken line. In this state as well, the piezoelectric bimorph element  17025  is stably joined with the cartilage conduction unit  17024  and vibrates without making contact with the inner wall of the sheath  17024   b , and the vibrations thereof are transmitted to the cartilage conduction unit  17024 . A connection cable  17024   d  is folded in a spiral in the state of  FIG. 183(E) . 
     One-Hundred Eleventh Embodiment 
       FIG. 184  is a schematic view of a one-hundred eleventh embodiment of an aspect of the present invention, and is configured as a stereo earphone. The one-hundred eleventh embodiment of  FIG. 184  has much in common with the one-hundred ninth embodiment of  FIG. 182 , and therefore the same parts have been given the same reference numerals, and a description thereof has been omitted. The one-hundred eleventh embodiment differs from one-hundred ninth embodiment in that the passage hole  17024   a  is not provided, and wearing is performed by insertion into the entrance to the external auditory meatus  30   a  rather than the space between the inner side of the tragus  32  and the anthelix  28   a . For this reason, a cartilage conduction unit  18024  is configured to be relatively small, as shown in  FIG. 184(A) . Also, the one-hundred eleventh embodiment is essentially configured for use with the external auditory meatus in the occluded state, and the cartilage conduction unit  18024  is deformed to form a gap between the inner wall of the entrance to the external auditory meatus  30   a  as later described in order to temporarily form an unoccluded state of the external auditory meatus. As previously described, external sounds can reach the tympanic membrane from the external auditory meatus even with a small gap. 
       FIG. 184(B)  is an enlarged view of the front surface of the earphone. In similar fashion to the one-hundred ninth embodiment, the sheath  18024   b  is embedded in and anchored to the lower part of the cartilage conduction unit  18024 . Furthermore, the upper end of a piezoelectric bimorph element  18025  is directly embedded in and anchored to the lower part of the cartilage conduction unit  18024  without making contact with the inner wall of the sheath  18024   b . In similar fashion to the one-hundred ninth embodiment, the lower end of the piezoelectric bimorph element  18025  is capable of freely vibrating inside the sheath  18024   b , the counteractions thereof are transmitted to the cartilage conduction unit  18024 , and satisfactory cartilage conduction to the ear cartilage is produced. In the one-hundred eleventh embodiment as described above, the cartilage conduction unit  18024  is deformed to form a gap between the inner wall of the entrance to the external auditory meatus  30   a  in order to temporarily achieve an unoccluded state in the external auditory meatus. The cartilage conduction unit  18024  has a hollow part  18024   g  in order to facilitate this deformation. In similar fashion to the one-hundred ninth embodiment, a connection cable is drawn out from the lower end of the piezoelectric bimorph element  18025 , and this is passed through the lower end of the sheath  18024   b  and connected to a stereo mini-plug, yet this is omitted from the drawing for simplicity. 
       FIGS. 184(C)  and (D) are views along the cross section B 2 -B 2  of  FIG. 184(B) .  FIG. 184(C)  shows a normal usage state, and the cartilage conduction unit  18024  is inserted into the entrance to the external auditory meatus  30   a  and forms an occluded state in the external auditory meatus. Also, in  FIG. 184(C) , the cross-sectional structure of the hollow part  18024   g  is shown. In  FIG. 184(C) , the piezoelectric bimorph element  18025  is illustrated to vibrate in the direction (in direction of vibration) along the external auditory meatus without making contact with the inner wall of the sheath  18024   b . Although not shown, such a structure is also common to the one-hundred ninth embodiment of  FIG. 182  and the one-hundred tenth embodiment of  FIG. 183 . 
       FIG. 184(D)  shows the case in which the external auditory meatus is temporarily placed in an unoccluded state, and shows the state in which the cartilage conduction unit  18024  has been deformed by pulling the sheath  18024   b  downward or pressing the upper part of the cartilage conduction unit  18024  downward. A gap is thereby formed between the upper part inner wall of the entrance to the external auditory meatus  30   a  and the upper part of the cartilage conduction unit  18024 , and external sounds that pass though this gap as indicated by the arrow  28   g  are able to reach the tympanic membrane from the external auditory meatus. The hollow part  18024   g  facilitates deformation of the cartilage conduction unit  18024  such as that in  FIG. 184(D) . The cartilage conduction unit  18024  is pressed downward, thereby promoting deformation of the lower part inner wall of the entrance to the external auditory meatus  30   a  and forming a gap between the upper part inner wall of the entrance to the external auditory meatus  30   a  and the upper part of the cartilage conduction unit  18024 . 
     One-Hundred Twelfth Embodiment 
       FIG. 185  is a schematic view of a one-hundred twelfth embodiment of an aspect of the present invention, and is configured as a stereo earphone. The one-hundred twelfth embodiment of  FIG. 185  has much in common with the one-hundred eleventh embodiment of  FIG. 184 , and therefore the same parts have been given the same reference numerals, and a description thereof has been omitted. The one-hundred twelfth embodiment differs from the one-hundred eleventh embodiment in that a cartilage conduction unit  19024  is accommodated without deformation in the cavum conchae  28   e  in order to achieve an unoccluded state in the external auditory meatus. The lower part of the cavum conchae  28   e  (above the intertragic notch  28   f ) is particularly advantageous as the location for accommodation, as shown in  FIGS. 185(B)  and (D). Satisfactory cartilage conduction can be produced even with the cartilage conduction unit  19024  accommodated in the cavum conchae  28   e , and cartilage conduction can be implemented with the external auditory meatus in an unoccluded state in the same manner as the one-hundred ninth embodiment of  FIG. 182 . 
       FIG. 185(A)  shows a state in which the cartilage conduction unit  19024  has been inserted into the entrance to the external auditory meatus  30   a  in the one-hundred twelfth embodiment as described above, and cartilage conduction is implemented with the external auditory meatus in an occluded state. In contrast,  FIG. 185(B)  shows the state in which the cartilage conduction unit  19024  has been removed from the entrance to the external auditory meatus  30   a  and accommodated in the cavum conchae  28   e , and cartilage conduction is implemented with the external auditory meatus in an unoccluded state. The cartilage conduction unit  19024  is configured with a spherical shape in order to facilitate sliding of the cartilage conduction unit  19024  between the state of  FIG. 185(A)  and the state of  FIG. 185(B) , and to avoid imparting pain. Also, the cartilage conduction unit  19024  is composed of a hard material because deformation is not envisioned. However, in lieu thereof, it is also possible to use an elastic material in the same manner as the one-hundred ninth embodiment of  FIG. 182 . 
       FIGS. 185(C)  and (D) are cross-sectional views corresponding to the states of  FIGS. 185(A)  and (B), respectively, and are views as seen from the same sectioned planes as  FIGS. 184(C)  and (D). In  FIG. 185(C) , it is apparent that the cartilage conduction unit  19024  is inserted into the entrance to the external auditory meatus  30   a , and the cartilage conduction is being implemented with the external auditory meatus in an occluded state. In contrast, it is apparent in  FIG. 185(D)  that the cartilage conduction unit  19024  withdrawn from the entrance to the external auditory meatus  30   a  is accommodated in the anthelix  28   a , and cartilage conduction is being implemented with the external auditory meatus in the unoccluded state. Also, a piezoelectric bimorph element  19025  vibrates without making contact with the inner wall of a sheath  19024   b , and the structure thereof is the same as that in the one-hundred ninth embodiment of  FIG. 182  to the one-hundred eleventh embodiment of  FIG. 184 , as shown in  FIGS. 185(C)  and (D). 
     The various features shown in each of the embodiments described above are not unique to individual embodiments, but the features of each embodiment can be substituted or combined, as appropriate, with features from other embodiments, wherever it is possible to make use of the advantages thereof. Also, the specific individual configurations in the embodiments can also be substituted with other equivalent means. For example, in the one-hundred tenth embodiment of  FIG. 183 , the configuration is such that the piezoelectric bimorph element  17025  is anchored to the cartilage conduction unit  17024  and the sheath  17024   b  slides up and down. The sheath  17024   b  functions as a branch part that serves as a knob when the cartilage conduction unit  17024  is to be attached or detached, but it is also possible to use a configuration in which the piezoelectric bimorph element  17025  itself is used as such a branch part, and the passage hole is opened and closed by sliding the piezoelectric bimorph element  17025  itself up and down. 
     The cartilage conduction unit  19024  of the one-hundred twelfth embodiment of  FIG. 185  is spherically configuration, but it is also possible to use a chamfered cylindrical shape or another shape. Furthermore, the cartilage conduction unit  17024  in the one-hundred tenth embodiment of  FIG. 183  is composed of a hard material, but it is also possible for the guide groove  17024   f  of the cartilage conduction unit  17024  to be composed of a rigid body and for the cartilage conduction unit  17024  to be composed of an elastic body. 
     One-Hundred Thirteenth Embodiment 
       FIG. 186  is a schematic view of a one-hundred thirteenth embodiment of an aspect of the present invention, and is configured as a stereo earphone. The one-hundred thirteenth embodiment of  FIG. 186  has much in common with the one-hundred ninth embodiment of  FIG. 182 , and therefore the same parts have been given the same reference numerals, and a description thereof has been omitted. The one-hundred thirteenth embodiment differs from one-hundred ninth embodiment in that a passage hole  20024   a  in a cartilage conduction unit  20024  is provided rearward when the cartilage conduction unit is worn on the ear, whereby the portion in contact with the inner side of the tragus  32  in the cartilage conduction unit  20024  is made to be a thick portion  20024   h , and a piezoelectric bimorph element  20025  and a sheath  20024   b  are held by the thick portion  20024   h . Also, in the one-hundred thirteenth embodiment of  FIG. 186 , the direction of vibration of the piezoelectric bimorph element  20025  is differ from the one-hundred ninth embodiment of  FIG. 182  as later described. 
       FIG. 186(A)  is a front view of the right-ear earphone mounted on the right ear  28  and shows an outline of the configuration described above. The right-ear earphone is illustrated as a broken line to make the relationship between the two readily apparent. It is apparent from the drawing that the entire right-ear stereo earphone is shaped in the form of the letter “q” and fits the shape of the right ear  28 , and the sheath  20024   b  hangs down below the right ear  28  from the cavum conchae  28   e  across to the intertragic notch  28   f.    
     Describing the shape of the cartilage conduction unit  20024  in greater detail with reference to  FIG. 186(A) , the thick portion  20024   h  has a rectilinear outer shape to adapt to the relatively flat inner side of the tragus  32 , and improves the close adhesion to the inner side of the tragus  32 . In contrast, the external shape of a thin portion  20024   i  rearward of the cartilage conduction unit  20024  is arcuate to adapt to the curved inner side of the anthelix  28   a , and improves the close adhesion to the inner side of the anthelix  28   a . In the same manner as the one-hundred ninth embodiment, the cartilage conduction unit  20024  is composed of an elastic body having strong resiliency, and conforms to personal differences in the width of the wearing space between the inner side of the tragus  32  and the anthelix  28   a  by deformation of wearing, and the cartilage conduction unit  20024  is designed not to fall from the wearing space due to the resiliency that accompanies deformation. In this case, rearward of the thin portion  20024   i  is a thin portion  20024   i , and therefore deformation is facilitated for accommodating personal differences. In  FIG. 186(A) , illustration of the piezoelectric bimorph element  20025  arranged inside the sheath  20024   b  is omitted for simplicity, but the vibration direction is set to be the direction that transverses the entrance to the external auditory meatus  30   a  in the manner indicated by the arrow  20025   b  (the direction substantially perpendicular to the center axis of the external auditory meatus). In the one-hundred ninth embodiment of  FIG. 182 , the direction of vibration of the piezoelectric bimorph element  16025  is set to be substantially parallel to the center axis of the external auditory meatus 
       FIG. 186(B)  is a front view of the right-ear earphone in a state worn on the right ear  28  in the same manner as  FIG. 186(A) , but the right ear  28  is omitted from the drawing and the configuration of the right-ear earphone is indicated by a solid line to facilitate understanding. The same reference numerals are assigned to the same portions, and a description is omitted unless required. In  FIG. 186(B) , the piezoelectric bimorph element  20025  arranged inside the sheath  20024   b  is illustrated with a broken line. The upper end part of the piezoelectric bimorph element  20025  is held by the thick portion  20024   h , and the lower end part freely vibrates without making contact with the sheath  20024   b  inside the sheath  20024   b , as described in detail below. The direction of vibration is parallel to the surface of the drawing as indicated by the arrow  20025   g . Therefore, the counteractions of the vibrations are transmitted to the cartilage conduction unit  20024 , and the vibrations in the direction that transverses the entrance to the external auditory meatus  30   a  as indicated by the arrow  20025   b  in  FIG. 186(A)  are transmitted to the tragus  32  as well as the ear cartilage around the entrance to the external auditory meatus  30   a.    
       FIG. 186(C)  is a side view of the earphone and can be understood in the same manner as  FIG. 182(B) . The piezoelectric bimorph element  20025  can be inserted relatively deeply into and supported by the cartilage conduction unit  20024  by using the thick portion  20024   h , as shown in  FIG. 186(B) . The depth thereof can be set so that the holding end  20025   c  of the piezoelectric bimorph element  20025  reaches further above the lower end of the passage hole  20024   a  (the inner edge thereof is indicated by a broken line), as shown in  FIG. 186(C) . Support of the piezoelectric bimorph element  20025  is ensured thereby. The piezoelectric bimorph element  20025  has a thin structure in the direction of vibration. Therefore, the thickness of the sheath  20024   b  can be reduced (in comparison with  FIG. 186(B)  and  FIG. 186(C) ) in the wearing direction on the right ear  28  by setting the direction of vibration to be the direction that transverses the entrance to the external auditory meatus  30   a , as indicated by the arrow  20025   b  in  FIG. 186(A) , and the sheath  20024   b  can be worn so as to hang down below the right ear  28  from the anthelix  28   a  across to the intertragic notch  28   f , even in a person having a narrow intertragic notch  28   f . Reducing the thickness of the sheath  20024   b  which functions as a branch part in this manner in the wearing direction on the right ear  28 , wearing that fits the shape of the right ear  28  is possible regardless of personal differences. 
       FIG. 186(D)  is an enlarged view of the front surface of the earphone. It is apparent from the drawing that the sheath  20024   b  is embedded in and anchored to the lower part of the cartilage conduction unit  20024 , but it is also possible to make use of the thick portion  20024   h  and embed the sheath relatively deeper in the lower part of the cartilage conduction unit  20024 , and to have the depth set so that the upper end of the sheath  20024   b  reaches further above the lower end of the passage hole  20024   a . As described above, the piezoelectric bimorph element  20025  can also be relatively deeply embedded in and supported by using the thick portion  20024   h  so that the holding end  20025   c  reaches above the lower end of the passage hole  20024   a . The upper end of the piezoelectric bimorph element  20025  is directly embedded in and anchored to the thick portion  20024   h  without making contact with the inner wall of the sheath  20024   b  in the same manner as the one-hundred ninth embodiment of  FIG. 182 . Also, the lower end of the piezoelectric bimorph element  20025  can freely vibrate inside the sheath  20024   b  without making contact with the inner wall of the sheath  20024   b , the counteractions thereof are transmitted to the cartilage conduction unit  20024 , and satisfactory cartilage conduction can be generated in the ear cartilage. A connection cable  20024   d  is drawn out from the lower end of the piezoelectric bimorph element  20025 , and the connection cable passes through the lower end of the sheath  20024   b  and is connected to a stereo mini-plug. 
       FIG. 186(E)  is an enlarged side view of the earphone, and is an enlarged view of  FIG. 186(C) . The same reference numerals are used for the same parts as  FIG. 186(D) , and a description thereof has been omitted unless otherwise required. The upper end of the piezoelectric bimorph element  20025  is directly embedded in and anchored to the thick portion  20024   h  without making contact with the inner wall of the sheath  20024   b  as shown in  FIG. 186(D)  as well. The lower end of the piezoelectric bimorph element  20025  is capable of freely vibrating inside the sheath  20024   b  without making contact with the inner wall of the sheath  20024   b . In a comparison of  FIG. 186(D)  and  FIG. 186 , it is readily apparent that setting the direction of vibration of the piezoelectric bimorph element  20025  to be the direction that transverses the entrance to the external auditory meatus  30   a  makes it possible to reduce the thickness in the direction in which the sheath  20024   b  is worn on the right ear  28 . 
     One-Hundred Fourteenth Embodiment 
       FIG. 187  is a schematic view of a one-hundred fourteenth embodiment of an aspect of the present invention, and is configured as a stereo earphone. The one-hundred fourteenth embodiment of  FIG. 187  has much in common with the one-hundred thirteenth embodiment of  FIG. 186 , and therefore the same parts have been given the same reference numerals, and a description thereof has been omitted. To avoid complexity in  FIG. 187 , the piezoelectric bimorph element  20025 , the internal structure of the sheath  20025   b , and the like are omitted from the drawing, and the same applies to  FIG. 186 . The one-hundred fourteenth embodiment of  FIG. 187  differs from one-hundred thirteenth embodiment of  FIG. 186  only in external appearance, and features the addition of a guide hook  20024   j  to the sheath  20024   b.    
       FIGS. 187(A)  and (B), in similar fashion to  FIGS. 186(A)  and (B), are front views of the right-ear earphone in a state worn on the right ear  28 , and as shown in the drawings, the guide hook  20024   j  is provided in a position that corresponds to the intertragic notch  28   f  on the inner side (the ear side) of the sheath  20024   b . The guide hook  20024   j  stably positions the sheath  20024   b  in the intertragic notch  28   f  during wearing, the sheath  20024   b  is snugly fitted with close adhesion to the intertragic notch  28   f , and the right-ear earphone is not liable to fall out from the cavum conchae  28   e.    
       FIG. 187(C)  shows a side view of the earphone in the same manner as  FIG. 186(C) . As shown in the drawing, the guide hook  20024   j  is provided to the ear side for wearing and in a position that cannot be seen from the outer side in a worn state.  FIG. 187(D)  is an enlarged view of the front surface of the earphone, and the guide hook  20024   j  on the inner is illustrated so as to be rotated 180 degrees from  FIG. 187(B)  and made visible.  FIG. 187(E)  is an enlarged side view of the earphone and is an enlargement of  FIG. 187(C) . 
     One-Hundred Fifteenth Embodiment 
       FIG. 188  is a schematic view of a one-hundred fifteenth embodiment of an aspect of the present invention, and is configured as a stereo earphone. The one-hundred fifteenth embodiment of  FIG. 188  has much in common with the one-hundred twelfth embodiment of  FIG. 185 , and therefore the same parts have been given the same two least-significant digits of the reference numerals, and a description thereof has been omitted. The one-hundred fifteenth embodiment differs from the one-hundred twelfth embodiment in that a cartilage conduction unit  21024  is used in a state constantly accommodated in the lower part of the cavum conchae  28   e , and switching between the occluded state and the unoccluded state of the external auditory meatus is carried out by movement of a movable earplug part  21024   k  connected by a lever  21024   m  to the cartilage conduction unit  21024 . In similar fashion to the one-hundred twelfth embodiment, satisfactory cartilage conduction is generated even when the cartilage conduction unit  21024  is accommodated in the cavum conchae  28   e , and it is thereby possible implement cartilage conduction with the external auditory meatus in the occluded state and the unoccluded state. 
       FIG. 188(A)  is a front view of the right-ear earphone worn on the right ear  28  in the same manner as  FIG. 185(A) , and the right-ear earphone is illustrated with a broken line so as to facilitate understanding of the two. In  FIG. 188(A) , the movable earplug part  21024   k  retracts from the entrance to the external auditory meatus  30   a  so as to be in contact with the inner wall of the anthelix  28   a  to achieve an unoccluded state of the external auditory meatus. At this time, the movable earplug part  21024   k  makes contact with the inner wall of the anthelix  28   a  and the bottom wall of the cavum conchae  28   e , and functions as an auxiliary cartilage conduction unit for conducting vibrations transmitted from the cartilage conduction unit  21024  to ear cartilage via the lever  21024   m . Furthermore, the movable earplug part  21024   k  makes contact with the inner wall of the anthelix  28   a  and the bottom wall of the cavum conchae  28   e , whereby wearing is stabilized and the right-ear earphone is made unlikely to fall out. 
     In contrast,  FIG. 188(B)  shows a state in which the movable earplug part  21024   k  is moved by clockwise rotation of the lever  21024   m  and inserted into the entrance to the external auditory meatus  30   a  to produce an occluded state of the external auditory meatus. An occluded effect is thereby produced in the external auditory meatus, and external noise is blocked.  FIG. 188(C)  and  FIG. 188(D)  correspond to  FIG. 188(A)  and  FIG. 188(B) , respectively, and are front views in which the configuration of the right-ear earphone is indicated by a solid to facilitate understand and the right ear  28  is omitted from the drawing. 
       FIG. 188(E)  and  FIG. 188(F)  are side views of the earphone corresponding to  FIG. 188(C)  and  FIG. 188(D) , respectively. In  FIG. 188(E)  showing the unoccluded state of the external auditory meatus, the movable earplug part  21024   k  is retracted, and external sounds can enter from the entrance to the external auditory meatus  30   a  as indicated by the arrow  28   g  and reach the tympanic membrane. In contrast, in  FIG. 188(F)  showing the occluded state of the external auditory meatus, the movable earplug part  21024   k  is inserted into the entrance to the external auditory meatus  30   a , and an occluded effect is produced in the external auditory meatus and external noise is blocked. The orientation of vibrations of the piezoelectric bimorph element  21025  in the one-hundred fifteenth embodiment of  FIG. 188  is the same as the one-hundred thirteenth embodiment of  FIG. 186 . Also, the internal structure of the sheath  21024   b  is the same as the one-hundred thirteenth embodiment of  FIG. 186 , but is omitted from the drawing to avoid complexity. 
     One-Hundred Sixteenth Embodiment 
       FIG. 189  is a schematic view of a one-hundred sixteenth embodiment of an aspect of the present invention, and is configured as a stereo earphone. The one-hundred sixteenth embodiment of  FIG. 189  has much in common with the one-hundred fifteenth embodiment of  FIG. 188 , and therefore the same parts have been given the same two least-significant digits of the reference numerals, and a description thereof has been omitted. The one-hundred sixteenth embodiment differs from the one-hundred fifteenth embodiment in that a movable earplug part  22024   k  for switching between an occluded state and an unoccluded state in the external auditory meatus is not a rotating type using a lever, but is rather a bending type in which the elasticity of an elastic support part  22024   m  is used. 
       FIG. 189(A)  is a front view of the right-ear earphone worn on the right ear  28  in the same manner as  FIG. 188(A) , and the right-ear earphone is illustrated with a broken line so as to facilitate understanding of the two. In  FIG. 189(A) , the movable earplug part  22024   k  is in a state positioned with a slight gap opened in front of the entrance to the external auditory meatus  30   a , and the external auditory meatus is in an unoccluded state. In this state, external air-conducted sound enters from the slight gap into the entrance to the external auditory meatus  30   a . Furthermore, the air-conducted sound generated by vibration of the movable earplug part  22024   k  reaches the tympanic membrane from the entrance to the external auditory meatus  30   a , and the movable earplug part functions as an auxiliary audio output unit for mainly supplementing the high-pitched regions. 
     In contrast,  FIG. 189(B)  shows a state in which the movable earplug part  22024   k  is slightly bent by the elasticity of the elastic support part  22024   m  and is inserted into the entrance to the external auditory meatus  30   a , producing an occluded state in the external auditory meatus. An occluded effect is thereby produced in the external auditory meatus, and external noise is blocked.  FIG. 189(C)  and  FIG. 189(D)  correspond to  FIG. 189(A)  and  FIG. 189(B) , respectively, and are front views in which the configuration of the right-ear earphone is indicated by a solid to facilitate understand and the right ear  28  is omitted from the drawing. 
       FIG. 189(E)  and  FIG. 189(F)  are side views of the earphone corresponding to FIG.  189 (C) and  FIG. 189(D) , respectively, and switching between the unoccluded state and the occluded state in the external auditory meatus is made more readily apparent than the front views. More specifically described, in  FIG. 189(E)  showing the unoccluded state of the external auditory meatus, the movable earplug part  22024   k  is retracted from the entrance to the external auditory meatus  30   a  leaving open a slight gap, and external sounds can enter from the entrance to the external auditory meatus  30   a  as indicated by the arrow  28   g  and reach the tympanic membrane. Furthermore, as described above, air-conducted sound from the movable earplug part  22024   k  reaches the tympanic membrane from the entrance to the external auditory meatus  30   a , supplementing cartilage conduction from a cartilage conduction unit  22024 . In contrast, in  FIG. 188(F)  showing the occluded state of the external auditory meatus, the movable earplug part  22024   k  is inserted into the entrance to the external auditory meatus  30   a , and an occluded effect is produced in the external auditory meatus and external noise is blocked. The orientation of vibrations of a piezoelectric bimorph element  22025  in the one-hundred sixteenth embodiment of  FIG. 189  is the same as the one-hundred thirteenth embodiment of  FIG. 186 . Also, the internal structure of the sheath  22024   b  is the same as the one-hundred thirteenth embodiment of  FIG. 186 , but is omitted from the drawing to avoid complexity. 
     The implementation of the features of the present invention described above are not limited to the aspects in the embodiments, implementation is also possible using other aspects whenever the benefits thereof can be utilized. For example, in the configuration of the one-hundred sixteenth embodiment of  FIG. 189 , the movable earplug part  22024   k  and the cartilage conduction unit  22024  are connected by a elastic support part  22024   m , but in lieu thereof, it is also possible to use a configuration in which the movable earplug part  22024   k , the cartilage conduction unit  22024 , and the elastic support part  22024   m  are all integrally molded using an elastic material. Also, in the configuration of the one-hundred fifteenth embodiment of  FIG. 187 , a guide hook  20024   j  is position below the cartilage conduction unit  20024 , but in lieu thereof, it is also possible to use a configuration in which the lower part of the cartilage conduction unit  20024  is partially notched and the guide hook  20024   j  may enter into the notched portion. However, in this case as well, the guide hook  20024   j  is supported by the sheath  20024   b  or integrally molded with the sheath  20024   b.    
     One-Hundred Seventeenth Embodiment 
       FIG. 190  is a schematic view of a one-hundred seventeenth embodiment of an aspect of the present invention, and is configured as a stereo earphone. The one-hundred seventeenth embodiment of  FIG. 190  has much in common with the one-hundred thirteenth embodiment of  FIG. 186 , and therefore the same parts have been given the same reference numerals, and a description thereof has been omitted. A portion of the drawing in  FIG. 186  is omitted in  FIG. 190  to avoid complexity. The one-hundred seventeenth embodiment of  FIG. 190  differs from the one-hundred thirteenth embodiment of  FIG. 186  in that the configuration is such that a slit  23024   a  is provided in place of a passage hole, whereby music or the like can be enjoyed by cartilage conduction without blocking external sounds. The slit  23024   a  is also significant as a structure for supporting a sheath  23024   b  on the cartilage conduction unit  23024  in a later-described manner. Furthermore, the one-hundred seventeenth embodiment of  FIG. 190  has an adhesive sheet  23024   i  for affixing the cartilage conduction unit  23024  to the cavum conchae  28   e  to prevent falling, and an earplug part  23024   k  for occluding the entrance to the external auditory meatus  30   a  as required. 
       FIG. 190(A)  is a front view of the right-ear earphone worn on the right ear  28  in the same manner as  FIG. 186 , and shows an outline of the configuration described above. In  FIG. 190(A)  as well, the right-ear earphone is illustrated as a broken line to make the relationship between the two readily apparent. 
       FIG. 190(B)  is a front view of the right-ear earphone in a state worn on the right ear  28  in the same manner as  FIG. 190(A) , and the right-ear earphone is illustrated with a broken line and the right ear  28  is omitted from the drawing so as to facilitate understanding of the configuration. The same reference numerals are used for the same parts, and a description thereof is omitted unless otherwise required. In  FIG. 190(B) , the adhesive sheet  23024   i  and the earplug part  23024   k  arranged on the ear side (the reverse side of the plane of the drawing) are illustrated with a broken line. It is apparent from  FIG. 190(B)  with reference to the right ear  28  of  FIG. 190(A)  that the adhesive sheet  23024   i  is provided in a position of close adhesion to the cavum conchae  28   e  rearward of the entrance to the external auditory meatus  30   a . Since the adhesive sheet  23024   i  is not provided to the earplug part  23024   k , the earplug part  23024   k  can be readily removed from the entrance to the external auditory meatus  30   a . The wearing and removal of the earplug part  23024   k  can be performed using the elasticity of the ear cartilage, the earplug part  23024   k  can be pressed into the entrance to the external auditory meatus  30   a  to occlude the entrance to the external auditory meatus, and the earplug part  23024   k  can be removed from the entrance to the external auditory meatus  30   a  to create a slight gap and direction external sounds into the external auditory meatus. In the case of the latter, the cartilage conduction unit  23024  is closely adheres to the cavum conchae  28   e  due to the adhesive sheet  23024   i , even when the earplug part  23024   k  is loose from the entrance to the external auditory meatus  30   a . The wearing and removal operation of the earplug part  23024   k  can be performed by pinching the sheath  23024   b.    
       FIG. 190(C)  is an enlarged view of  FIG. 190(B) . It is apparent from the drawing that the right side of the drawing of the slit  23024   a  is a connection part  23024   h , and a holding end  23025   c  of a piezoelectric bimorph element  23025  is inserted therein. By providing the slit  23024   a , the sheath  23024   b  is inserted from the exterior so as to cover the connection part  23024   h . Inserting the piezoelectric bimorph element  23025  inside the connection part  23024   h  in this manner holds the piezoelectric bimorph element  23025  in the cartilage conduction unit  23024 , and by inserting the sheath  23024   b  over the outer side so as to cover the connection part  23024   h  makes it possible to reliably join the sheath  23024   b  to the cartilage conduction unit  23024 , and protects the piezoelectric bimorph element  23025  without contact with the inner side of the sheath  23024   b.    
       FIG. 190(D)  is an enlarged side view of the right-ear earphone, the left side in the drawing corresponds to the entrance to the external auditory meatus  30   a  side, the front side as viewed from the plane of the drawing is the occipital side in the worn state, and the back side as viewed from the plane of the drawing is the face side in the worn state. It is apparent from  FIG. 190(D)  that the adhesive sheet  23024   i  is provided in a position for closely adhering to the cavum conchae  28   e  rearward of the entrance to the external auditory meatus  30   a . The adhesive sheet  23024   i  can be repeatedly affixed to the cavum conchae  28   e , and can be peeled away from the cartilage conduction unit  23024  and replaced with a new one when the adhesive force is reduced or the adhesive sheet becomes soiled. It is possible to use, e.g., “Opsite Gentle Roll” (registered trademark) or the like, which is a roll film the uses a silicone adhesive. 
       FIG. 191  is a conceptual perspective view of the one-hundred seventeenth embodiment shown in  FIG. 190 , and illustrates the structure being rotated 180 degrees from the state in  FIG. 190(C)  so that the earplug part  23024   k  and the adhesive sheet  23024   i  on the inner side can be seen. In  FIG. 191 , the parts are simplified and illustrated as being rectangular parallelepiped or columnar for convenience of description of the structural relationship, but the actual external appearance of the cartilage conduction unit  23024  and earplug part  23024   k  and the contour of the adhesive sheet  23024   i  of the one-hundred seventeenth embodiment are as shown in  FIG. 190  and have a chamfered smoothness so as to be contoured in contact with the ear cartilage and the entrance to the external auditory meatus  30   a.    
       FIG. 191(A)  shows a disassembled state prior to the sheath  23024   b  being inserted over the connection part  23024   h  in order to show the particular relationship between the connection part  23024   h  and the piezoelectric bimorph element  23025  and sheath  23024   b . It is apparent from  FIG. 191(A)  that the piezoelectric bimorph element  23025  is first inserted into the connection part  23024   h . The piezoelectric bimorph element  23025  is thereby held by the cartilage conduction unit  23024 . The sheath  23024   b  is mounted over the outer side of the connection part  23024   h  so as to cover the connection part, whereby the sheath  23024   b  is joined to the cartilage conduction unit  23024 . At this point, the connection cable  23024   d  is drawn out from the hold  23024   n  to the lower part of the sheath  23024   b . The sheath  23024   b  can thereby be reliably joined to the cartilage conduction unit  23024 , and the piezoelectric bimorph element  23025  can be protected without being in contact with the sheath  23024   b . For reference,  FIG. 191(B)  shows a downscaled perspective view of the completely assembled form obtained by inserting the sheath  23024   b  over the outer side of the connection part  23024   h.    
     One-Hundred Eighteenth Embodiment 
       FIG. 192  is a cross-sectional schematic view of a one-hundred eighteenth embodiment of an aspect of the present invention, and is configured as a stereo earphone. The one-hundred eighteenth embodiment of  FIG. 192  has much in common with the one-hundred eleventh embodiment of  FIG. 184 , and therefore the same parts have been given the same reference numerals, and a description thereof has been omitted. A portion of the drawing in  FIG. 184  is omitted in  FIG. 192  to avoid complexity. The one-hundred eighteenth embodiment of  FIG. 192  differs from the one-hundred eleventh embodiment of  FIG. 184  in that a projecting part  24024   p  is formed on the surface of a cartilage conduction unit  24024  composed of an elastic body, and the stereo earphone can be stably worn with the external auditory meatus in an unoccluded state without manually pressing and pulling in the manner shown in  FIG. 184(D)  in the one-hundred eleventh embodiment to thereby temporarily form an unoccluded state in the external auditory meatus. 
       FIG. 192(A)  shows the state in which the cartilage conduction unit  24024  has been inserted so that the distal end of the projecting part  24024   p  lightly contact s the entrance to the external auditory meatus  30   a  in a natural no-load state. In this state, the cartilage conduction unit  24024  is stably worn in the entrance to the external auditory meatus  30   a  due to friction caused by contact with the distal end of the entrance to the external auditory meatus  30   a  and repulsion-restorative force produced by the slight elastic deformation thereof. Also, the projecting part  24024   p  projects in a manner inclined outward and upward so as to widen outward due to the frictional force between the entrance to the external auditory meatus  30   a  and the distal end of the cartilage conduction unit  24024  when force is applied in the dislodging direction thereof, and therefore has a structure that is more unlikely to fall out.  FIG. 192(B)  is a view along the cross section B 2 -B 2  in  FIG. 192(A) , and shows that the distal end of the projecting part  24024   p  and the entrance to the external auditory meatus  30   a  are in contact with each other, and that external sounds can enter from the gap between the entrance to the external auditory meatus  30   a  and the cartilage conduction unit  24024  in other portions as indicated by the arrow  28   g  and reach the tympanic membrane. 
       FIG. 192(C)  shows the state in which the cartilage conduction unit  24024  has been firmly pressed by the entrance to the external auditory meatus  30   a , and shows that the projecting part  24024   p  is pressed down and embedded in the surface of the cartilage conduction unit  24024 , and that the cartilage conduction unit  24024  is in contact with the entrance to the external auditory meatus  30   a  around entire periphery thereof.  FIG. 192(D)  is a view along the cross section B 2 -B 2  in  FIG. 192(C) , and shows that the entrance to the external auditory meatus  30   a  is occluded by the cartilage conduction unit  24024  being in contact with the entrance to the external auditory meatus  30   a  around the entire periphery thereof. Naturally, the cartilage conduction unit  24024  can be stably worn in the entrance to the external auditory meatus  30   a  in this state as well. 
     In this manner, in the one-hundred eighteenth embodiment of  FIG. 192 , the insertion state between the state of  FIGS. 192(A)  and (C) and the state of  FIGS. 192(B)  and (D) is changed without temporarily forming an unoccluded state in the external auditory meatus by manually pressing and pulling in the manner of  FIG. 184(D)  in the one-hundred eleventh embodiment, whereby the stereo earphone can be stably worn with the external auditory meatus in an unoccluded state and the external auditory meatus in an occluded state. 
     One-Hundred Nineteenth Embodiment 
       FIG. 193  is a schematic view and a block view according to an aspect of a one-hundred nineteenth embodiment of the present invention, and is configured as a stereo earphone and a headset body connected thereto. The stereo earphone in the one-hundred nineteenth embodiment of  FIG. 193  has much in common with the one-hundred thirteenth embodiment of  FIG. 186 , and the headset body has much in common with the headset body of the eighty-ninth embodiment of  FIG. 139 . Therefore, the same parts have been given the same reference numerals, and a description thereof has been omitted. Being mostly unrelated, a portion of the drawing in  FIG. 193  is omitted. The one-hundred nineteenth embodiment of  FIG. 193  differs from the one-hundred thirteenth embodiment and the eighty-ninth embodiment in that one end of a low-band piezoelectric bimorph element  25025   a  and an intermediate-to-high-band piezoelectric bimorph element  25025   b  is supported in a shared cartilage conduction unit  25024  and the other ends are capable of freely vibrating, and the low-band piezoelectric bimorph element  25025   a  and the intermediate-to-high-band piezoelectric bimorph element  25025   b  are driven from separate channels that have been separately equalized. 
     As previously described, in the example of measurement data shown in  FIG. 79 , a comparison of sound pressure in the non-contact state indicated by the solid line and the sound pressure at a contact pressure of 250 force-grams indicated by the dot-dash line shows that the sound pressure in the external auditory meatus at a depth of 1 cm from the entrance to the external auditory meatus is increased by at least 10 dB by contact in the main frequency band (50 Hz to 2300 Hz) of speech. 
     In the audio field of stereo earphones and the like, a sound quality that covers a higher frequency band is preferred, and in view of the change in sound pressure in the non-contact state and the sound pressure at a contact pressure of 250 force-grams in the example of measurement data shown in  FIG. 79 , an increase in sound pressure of at least 5 dB is observed even at about 3 kHz to 7 kHz.  FIG. 79  is, at best, an example of measurement data and a strict quantitative evaluation has no significance, but  FIG. 79  does indicate that at least for cartilage conduction, there are sensitivity characteristics that cover a higher frequency region and not just the main frequency band of speech. 
     The one-hundred nineteenth embodiment of  FIG. 193  is a configuration made in view of the characteristics of cartilage conduction as described above. In addition to a first sheath  25024   b , a second sheath  25024   q  is provided to the cartilage conduction unit  25024 , as shown in  FIG. 119(A) , and one end of the low-band piezoelectric bimorph element  25025   a  and the intermediate-to-high-band piezoelectric bimorph element  25025   b  is held in the cartilage conduction unit  25024  so that there is no contact with the inner surface of the first sheath  25024   b  as well as the second sheath  25024   q , respectively, as shown in  FIG. 119(B) . The length of the low-band piezoelectric bimorph element  25025   a  is greater than that of the intermediate-to-high-band piezoelectric bimorph element  25025   b.    
     The first sheath  25024   b  is accommodated in the intertragic notch  28   f , as shown in  FIG. 193(A) , the second sheath  25024   q  is in a position for accommodation in the incisura anterior  28   h  (see structural diagram of the ear of  FIG. 80(A) ), and positioning and perception of stability is enhances when the cartilage conduction unit  25024  is worn in a manner straddling the tragus  32 . Forward of the incisura anterior  28   h  and below the crus of the tragus is open space in terms of the structure of the ear and is therefore suitable for providing the second sheath  25024   q.    
     As shown in the block view of  FIG. 193(C) , the audio output from the acoustic processing circuit  8338  is separated into a low-band signal and an intermediate-to-high band signal, and each are equalized and amplified in a low-band equalizer/amplifier  25040   a  and an intermediate-to-high band equalizer/amplifier  20540   b  using respectively separate channels. The signals from the low-band equalizer/amplifier  25040   a  and the intermediate-to-high band equalizer/amplifier  20540   b  are connected to the low-band piezoelectric bimorph element  25025   a  and the intermediate-to-high-band piezoelectric bimorph element  25025   b , respectively, by a first channel connection part  25046   a  and a second channel connection part  25046   b , and drive the piezoelectric bimorph elements. One end of the low-band piezoelectric bimorph element  25025   a  and the intermediate-to-high-band piezoelectric bimorph element  25025   b  is held by a shared cartilage conduction unit  25024 , and the cartilage conduction unit  25024  therefore conducts the physically mixed vibrations to the ear cartilage by cartilage conduction. Audio signals in at least the band of about 200 Hz to 7 kHz (see the example of measurement data shown in  FIG. 79 ), which can be covered by cartilage conduction, can be heard by cartilage conduction. When such relatively wide-band cartilage conduction is to be implemented, the one-hundred nineteenth embodiment of  FIG. 193  increases the degree of freedom of a piezoelectric bimorph element and the equalizer adapted thereto and facilitates obtainment of better sound quality by dividing the bandwidth to be handled by two piezoelectric bimorph elements having different lengths. 
     As described above, an example for configuring a cartilage conduction vibration unit using a plurality of cartilage conduction vibration sources is also shown in  FIG. 94(D) . Specifically, an example is described in which, in the cordless handset  5881   c  of the third modification of the sixty-second embodiment in  FIG. 94(D) , the low-end piezoelectric bimorph element  2525   g  and the high-end piezoelectric bimorph element  2525   h  are directly affixed to the inner side of the cartilage conduction unit  5824   c  so as to be in contact with the vibration surface side of the piezoelectric bimorph elements, and the vibrations of the piezoelectric bimorph element  2525   g  and the piezoelectric bimorph element  2525   h  are directly transmitted to the cartilage conduction unit  5824   c , whereby a plurality of cartilage conduction vibration sources having different frequency characteristics are made to function in a complementary fashion to improve the frequency characteristics of cartilage conduction. 
     The implementation of the features of the present invention described above is not to be limited to the aspects in the above embodiments, and the invention can be implemented using other aspects as well, wherever it is possible to benefit from the advantages thereof. Embodiments in which an adhesive sheet is used is not limited to a configuration such as the one-hundred seventeenth embodiment shown in  FIGS. 189 and 190 . For example, in the one-hundred twelfth embodiment shown in  FIG. 185 , it is possible to provide an adhesive sheet at least the surface of the hemisphere of the ear cartilage contact side of the cartilage conduction unit  19024 , to adhere the cartilage conduction unit  19024  to the entrance to the external auditory meatus  30   a  in the state of  FIGS. 185(A)  and (C), and adhere the cartilage conduction unit  19024  to the cavum conchae  28   e  in the state of  FIGS. 185(B)  and (D). 
     An example of a configuration for enjoying music or the like by cartilage conduction without blocking external sounds is not limited to providing a slit  23024   a  such as in the one-hundred seventeenth embodiment shown in  FIGS. 189 and 190 . In other words, it is also possible to provide a larger hole in lieu of parallel groove-shaped slits such as in the one-hundred seventeenth embodiment for introducing external sounds, as long as the shape allows the piezoelectric bimorph element  23025  to be inserted inside the connection part  23024   h  and allows the sheath  23024   b  to be provided so as to cover the connection part  23024   h  from the outside. The configuration of the sheath  23024   b  for covering, from the outside, the connection part  23024   h  into which the piezoelectric bimorph element  23025  has been inserted is also not limited to inserted from the bottom as in the one-hundred seventeenth embodiment, and it is also possible to use a configuration in which the connection part  23024   h  is wedged in from two sides, the front and back or the left and right. 
     Furthermore, in implementation of relatively wide-band cartilage conduction in the one-hundred nineteenth embodiment of  FIG. 193 , the bands are divided in the equalizer for two piezoelectric bimorph elements having differing lengths, but it is also possible to implement cartilage conduction for audio that included a main frequency band for speech, which is about 3 kHz to 7 kHz, by devising a single cartilage conduction vibration source and equalizer. 
     The features in the various embodiments described above are not limited to being used in each of the individual embodiments, and the features can be combined to form a single embodiment. For example, the feature of the adhesive sheet and the earplug part shown in  FIG. 190  can be used in the one-hundred nineteenth embodiment of  FIG. 193  as well. In this case, a slit or the like illustrated in  FIG. 190  is used in place of the passage hole illustrated in  FIG. 193  in the one-hundred nineteenth embodiment. Also, the configuration in which the piezoelectric bimorph element  23025  is inserted into the connection part  23024   h  and the sheath  23024   b  is covered thereon as shown in the one-hundred seventeenth embodiment of  FIG. 190  can also be used as the configuration of first sheath  25024   b  as well as the second sheath  25024   q  in the one-hundred nineteenth embodiment of  FIG. 193 . 
     One-Hundred Twentieth Embodiment 
       FIG. 194  is a schematic view of a one-hundred twentieth embodiment of an aspect of the present invention, and is configured as a stereo earphone.  FIG. 194(A)  is a front view (corresponding to the side surface of the face) of the right-ear earphone worn on the right ear  28 . Illustration of the face other than the right ear  28  is omitted for simplicity, a description related only to the right ear is provided, and a description of the left-ear earphone, which has the same configuration, is omitted. In the same manner as the one-hundred ninth embodiment of  FIG. 182  and elsewhere, the right-ear earphone and the left-ear earphone can be connected to the stereo mini-jack for external output of a mobile telephone or a mobile music terminal by a stereo mini-plug. In the one-hundred twentieth embodiment of  FIG. 194 , the cartilage conduction unit is worn on ear cartilage using an adhesive sheet in the same manner as the one-hundred seventeenth embodiment of  FIG. 190 , but the cartilage conduction unit is worn on the inner side of the ear cartilage in the one-hundred seventeenth embodiment, whereas the cartilage conduction unit is worn on the outer side of the ear cartilage in the one-hundred twentieth embodiment. 
     Described more specifically, the cartilage conduction unit  23024  closely adheres to the cavum conchae  28   e , which is on the inner side of the ear, as shown in  FIG. 190(A)  in the one-hundred seventeenth embodiment. (For convenience of description in  FIG. 190(A) , the cartilage conduction unit  23024  is shown with a broken line, and the cartilage conduction unit  23024  in the worn state can be seen from the side surface of the face.) In contrast, in the one-hundred twentieth embodiment, a cartilage conduction unit  26024  for the right-ear earphone is made to closely adhere to the ear cartilage using an adhesive sheet on back part of the outer side  1828  of auricle attachment part, which is the base of the ear  28 , as is apparent in  FIG. 194(A) . As a result, in the worn state, most of the cartilage conduction unit  26024  is hidden (a broken line in the drawing) on the reverse side of the auricle in the right ear  28 , and the lower end part is visible from the auricle, as shown in  FIG. 194(A) . 
     In such a wearing style of the cartilage conduction unit  26024 , there is no portion covering the auricle, and the ear hole is open. Also, cartilage conduction is transmitted with good efficiency in a state in which the cartilage conduction unit  26024  has been retracted downward, even though the cartilage conduction unit  26024  is arranged on the outer side of the ear cartilage. Therefore, when glasses are worn, the cartilage conduction unit  26024  can be prevented from interfering with the bows of the glasses, allowing use regardless of whether glasses are being worn. 
       FIG. 194(B)  is a view of the right ear  28  as seen from the back side of the head, the appearance in which the cartilage conduction unit  26024  of the right-ear earphone is made to closely adhere to the ear cartilage so as to be wedged between the temporal bone mastoid process  8623   a  and the outer side  1828  of the auricle attachment part, which is the base of the right ear  28 . An adhesive sheet is provided to the cartilage conduction unit  26024 , bonding to the rear part of the outer side  1828  of the auricle attachment part prevents falling off. 
       FIG. 194(C)  is a front cross-sectional view of the earphone as seen from the orientation corresponding to  FIG. 194(A) . A structure is apparent from the cross-sectional view of  FIG. 194(C)  in which the upper part of the cartilage conduction unit  26024  is composed of an elastic body material, and a sheath  26024   b  composed of a hard material covers the cartilage conduction unit. The upper end  26025   c  of a piezoelectric bimorph element  26025  is directly embedded in and anchored to the upper part elastic body of the cartilage conduction unit  26024  without being in contact with the inner wall of the sheath  26024   b . On the other hand, the lower end of the piezoelectric bimorph element  26025  is capable of freely vibrating inside the sheath  26024   b , the counteractions thereof are transmitted to the upper part elastic body of the cartilage conduction unit  26024 , and good cartilage conduction to the bonded ear cartilage is produced. A connection cable  26024   d  is drawn out from the lower end of the piezoelectric bimorph element  26025 , and this is passed through the lower end of the sheath  26024   b  and connected to a stereo mini-plug. This internal structure is the same as the one-hundred eighty-second embodiment of  FIG. 182  and elsewhere. 
       FIG. 194(D)  is a cross-sectional view rotated 90 degrees from the cross-sectional view of  FIG. 194(C) , and is a view as seen from the orientation corresponding to  FIG. 194(C) . The arrow  26025   g  indicates the direction of vibration of the piezoelectric bimorph element  26025 , the direction being parallel to the plane of the drawing, i.e., the direction along the external auditory meatus. An adhesive sheet  26024   i  is provided to the auricle side of the upper part elastic body of the cartilage conduction unit  26024 , and the cartilage conduction unit  26024  is thereby bonded to the auricle side of the base of the right ear  28 . The adhesive sheet  26024   i  is replaceable and can be peeled away from the upper part elastic body of the cartilage conduction unit  26024 , and a new adhesive sheet can be reapplied when attachment to and removal from the right ear  28  has exceeded a predetermined number of times and the adhesive force has weakened. 
       FIG. 194(E)  shows a modification of the one-hundred twentieth embodiment, and is a cross-sectional view of the cartilage conduction unit  26024  as seen from the same direction as  FIG. 194(D) . In the modification, the range over which an adhesive sheet  26024   r  is provided extends to not only the upper part elastic body of the cartilage conduction unit  26024 , but also to the sheath  26024   b  therebelow. 
     One-Hundred Twenty-First Embodiment 
       FIG. 195  is a schematic view of a one-hundred twenty-first embodiment of an aspect of the present invention, and is configured as a stereo earphone. The relationship with the ear in the one-hundred twenty-first embodiment of  FIG. 195  is the same as the one-hundred twentieth embodiment of  FIG. 194  and is therefore omitted from the drawing. The structure thereof also has much in common with the one-hundred twentieth embodiment, and the same parts have been given the same reference numerals, and a description thereof has been omitted unless otherwise required. The one-hundred twenty-first embodiment of  FIG. 195  differs from the one-hundred twentieth embodiment of  FIG. 195  in the external shape of the upper part elastic body of a cartilage conduction unit  27024  and the shape of an adhesive sheet  27024   i ; and a sheath  27024   b  and as well as other structures and the internal structure are the same as the one-hundred twentieth embodiment. 
       FIG. 195(A)  is a cross-sectional view as seen from the orientation corresponding to  FIG. 194(C)  of the one-hundred twentieth embodiment, and the upper part elastic body portion of the cartilage conduction unit  27024  has a surface curvature referred to as a curved surface  27024   s  configured so as to fit the periphery of the base of the right ear  28 .  FIG. 195(B)  is cross-sectional view as seen from the orientation corresponding to  FIG. 194(D)  of the one-hundred twentieth embodiment, and the curved surface  27024   s  of the upper part elastic body portion of the cartilage conduction unit  27024  is shaped to fit the outer side of the auricle in the vicinity of the attachment part. The adhesive sheet  27024   i  is also affixed in a curve shape in accompaniment therewith. The adhesive sheet  27024   i  is replaceable in similar fashion to the one-hundred twentieth embodiment. 
       FIGS. 195(C)  and (D) show a view along the cross section B 1 -B 1  in the orientation of  FIGS. 195(A)  and (B), respectively. It is apparent from  FIGS. 195(C)  and (D) that the curved surface  27024   s  has a shape that fits into the gap formed between the temporal bone mastoid process  8623   a  and the rear part of the outer side  1828  of the auricle attachment part, which is the base of the right ear  28 . The adhesive sheet  27024   i  is also provided not only to the auricle side but also to the distal end portion in the fitting-in direction. The adhesive sheet  27024   i  is not provided to the temporal bone mastoid process  8623   a  side facing the auricle, but is configured so as to avoid interfering with the freedom of transmitting vibrations to the auricle side, and prevents unpleasantness of the base of the auricle and the temporal bone mastoid process  8623   a  bonding together. 
     One-Hundred Twenty-Second Embodiment 
       FIG. 196  is a schematic view of a one-hundred twenty-second embodiment of an aspect of the present invention, and is configured as a stereo earphone. The one-hundred twenty-second embodiment of  FIG. 196  has much in common with the one-hundred twentieth embodiment of  FIG. 194 , and therefore the same parts have been given the same two least-significant digits and appended letters of the reference numerals, and a description thereof has been omitted unless otherwise required. The one-hundred twenty-second embodiment of  FIG. 196  differs from the one-hundred twentieth embodiment of  FIG. 194  in that the upper elastic body portion of the cartilage conduction unit is bent in relation to the sheath. 
       FIG. 196(A)  is a front view (corresponding to the substantially anterior-posterior direction of the face) of the right-ear earphone corresponding to  FIG. 194(A)  of the one-hundred twentieth embodiment. It is apparent from  FIG. 196(A)  that in a cartilage conduction unit  28024  of the right-ear earphone, the upper elastic body portion is bent in relation to a sheath  28024   b , and this bending is such that the entire cartilage conduction unit  28024  better fits around the base of the right ear  28 .  FIG. 196(B)  is a cross-sectional view corresponding to  FIG. 194(C)  of the one-hundred twentieth embodiment. An upper end  28025   c  of a piezoelectric bimorph element  28025  is embedded in and anchored to the upper elastic body of the cartilage conduction unit  28024  in an inclined manner. In contrast, the sheath  28024   b  composed of a hard material is inclined and made to cover the upper elastic body of the cartilage conduction unit  28024  so that the piezoelectric bimorph element  28025  does not make contact with the inner wall thereof. 
       FIG. 196(C)  is a front view showing the left-ear earphone together with the left ear  30 , and is a symmetrical illustration that conforms to the right-ear earphone in  FIG. 196(A) . It is apparent from  FIG. 196(C)  that in a cartilage conduction unit  29024  of the left-ear earphone as well, the upper elastic body portion is bent in relation to a sheath  29024   b , and the entire cartilage conduction unit  28024  better fits around the base of the left ear  30  by the bending.  FIG. 196(D)  is a cross-sectional view of the cartilage conduction unit  29024  in the left-ear earphone of  FIG. 196(C) , and is a symmetrical illustration that conforms to the right-ear earphone in  FIG. 196(B) . The internal structure thereof is the same as that of the cartilage conduction unit  28024  for the right-ear earphone, except that the bent direction is reverse, and therefore a description is omitted. 
     In the one-hundred twenty-second embodiment, an adhesive sheet (not shown) is provided to the forward side of the upper elastic body portion as viewed from the plane of the drawing in the right-ear cartilage conduction unit  28024  of  FIG. 196(B)  and the left-ear cartilage conduction unit  29024  of  FIG. 196(D) . The right-ear cartilage conduction unit  28024  and the left-ear cartilage conduction unit  29024  are thereby bonded to the base portion of the reverse side of the auricle of the right ear  28  and the left ear  30 , respectively. Thus, in the one-hundred twenty-second embodiment, the bent direction and the placement direction of the adhesive sheet are symmetrical between the right-ear cartilage conduction unit  28024  and the left-ear cartilage conduction unit  29024 , and the right-ear earphone and the left-ear earphone can be bonded to the right ear  28  and the left ear  30 , respectively, without mutually confusing the two. 
     In the same manner as the one-hundred twenty-second embodiment, in the one-hundred twenty-first embodiment of  FIG. 195  as well, the curved surface  27024   s  is symmetrical between the right-ear cartilage conduction unit  27024  and the left-ear cartilage conduction unit (not shown), and in accordance therewith, the shape of the adhesive sheet  27024   i  is also symmetrical in the right-ear cartilage conduction unit and the left-ear cartilage conduction unit. Therefore, in the one-hundred twenty-first embodiment of  FIG. 195  as well, the right-ear earphone and the left-ear earphone can be bonded to the right ear  28  and the left ear (not shown), respectively, without mutually confusing the two. Also, in the one-hundred twenty-first embodiment, the curved surface  27024   s  is symmetrical between the right-ear cartilage conduction unit and the left-ear cartilage conduction unit, and the adhesive sheet  27024   i  can be reaffixed without confusing the adhesive sheet for right ear and the left ear when the adhesive sheet is to be replaced. 
     One-Hundred Twenty-Third Embodiment 
       FIG. 197  is a schematic view of a one-hundred twenty-third embodiment of an aspect of the present invention, and is configured as a stereo earphone. The one-hundred twenty-third embodiment of  FIG. 197  has much in common with the one-hundred twentieth embodiment of  FIG. 194 , and therefore the same parts have been given the same two least-significant digits and appended letters of the reference numerals, and a description thereof has been omitted unless otherwise required. The one-hundred twenty-third embodiment of  FIG. 197  differs from the one-hundred twentieth embodiment of  FIG. 194  in terms of the direction of vibration of a piezoelectric bimorph element  30025 . 
       FIGS. 197(A)  to (C) of the one-hundred twenty-third embodiment correspond to  FIG. 194(A)  to (C), respectively, of the one-hundred twentieth embodiment. However, the direction of vibration of the piezoelectric bimorph element  30025  is parallel to the plane of the drawing, i.e., the direction that transverses the external auditory meatus, as indicated by the arrow  30025   g  in  FIG. 197(C) . An adhesive sheet  30024   i  is provided to the auricle side of the upper elastic body of a cartilage conduction unit  30024 , as shown in  FIG. 197(D) , and the cartilage conduction unit  30024  is bonded to the auricle side of the base of the right ear  28  in similar fashion to the one-hundred twentieth embodiment. In the one-hundred twenty-third embodiment as well, the adhesive sheet  30024   i  can be replaced and can be peeled away from the upper part elastic body of the cartilage conduction unit  26024 , and a new adhesive sheet can be reapplied when attachment to and removal from the right ear  28  has exceeded a predetermined number of times and the adhesive force has weakened. 
     The various features shown each of the embodiments described above are not limited to being used in individual embodiments, but various modifications can be made wherever it is possible to make use of the advantages thereof, and the features may be combined into a single embodiment. For example, in the one-hundred twentieth embodiment to one-hundred twenty-third embodiment shown in  FIG. 194  to  FIG. 197 , it is possible for the upper elastic body portion of the cartilage conduction unit to be composed of a hard material. Also, the one-hundred twenty-first embodiment shown in  FIG. 195  and the one-hundred twenty-second embodiment shown in  FIG. 196  may be combined, a curved surface may be provided to the upper elastic body portion of the cartilage conduction unit, and the upper elastic body portion of the cartilage conduction unit may be bent in relation to the sheath. 
     One-Hundred Twenty-Fourth Embodiment 
       FIG. 198  is a schematic view related to a one-hundred twenty-fourth embodiment according to an aspect of the present invention, and is configured as a stereo earphone  31081 . The stereo headphones  31081  has a right-ear audio output part  31024  and a left-ear audio output part  31026 . The right-ear audio output part  31024  and the left-ear audio output part  31026  have ear pads  31024   a  and  31026   a , respectively, composed of an elastic body, and electromagnetic vibrators  31025   a  and  31025   b , respectively, are embedded therein. Furthermore, air conduction-generating electromagnetic speakers  31024   b  and  31026   b  are provided to the right-ear audio output part  31024  and the left-ear audio output part  31026 , respectively, in the portions surrounded by the ear pads  31024   a  and  31026   a . In accordance with above configuration, the ear pad  31024   a  and the electromagnetic vibrator  31025   a  constitute a right-ear cartilage conduction unit that makes contact with the inner side of the auricle of the right ear. Similarly, the ear pad  31026   a  and the electromagnetic vibrator  31025   b  constitute a left-ear cartilage conduction unit that makes contact with the inner side of the auricle of the left ear. Thus, the one-hundred twenty-fourth embodiment is configured so as to use both a cartilage conduction unit and an air conduction speaker, and the frequency characteristics of the air conduction speaker reinforce the cartilage conduction unit, which is good in low-pitched regions. 
       FIG. 199  is an enlarged cross-sectional view of the right-ear audio output part  31024  and a block view of the internal configuration of the one-hundred twenty-fourth embodiment shown in  FIG. 198 . The stereo headphones  31081  receive audio signals from a mobile music player, a mobile telephone, or the like by using a short-range communication unit  31087  provided to the right-ear audio output part  31024 . Also, the stereo headphones  31081  is capable of operating in any of a “normal mode,” a “noise-cancelling mode,” and an “ambient sound introduction mode” in accordance with a setting made by operation of an operation unit  31009 . 
     In the “normal mode,” an audio signal inputted from the short-range communication unit  31087  is sent from a control unit  31039  to a cartilage conduction equalizer  31083   a , and based on the output thereof, the electromagnetic vibrator  31025   a  is driven by a cartilage conduction drive unit  31040   a . At the same time, the audio signal inputted from the short-range communication unit  31087  is sent from the control unit  31039  to an air conduction equalizer  31038   b , and based on the output thereof, the electromagnetic speaker  31024   b  is driven by an air conduction drive unit  31040   b . The frequency characteristics of the air conduction speaker thereby reinforce the cartilage conduction unit, which is good in the low-pitched regions. In particular, when an external auditory meatus occlusion effect is produced by close adhesion between the auricle and the ear pad  31024   a , low-pitched regions can be enhanced. 
     In the “noise-cancelling mode,” ambient sounds picked up from an ambient sound microphone  31038  are inverted in phase and mixed by the control unit  31039 , are sent from the air conduction equalizer  31038   b  to the air conduction drive unit  31040   b , and are audio-outputted from the electromagnetic speaker  31024   b . The phase-inverted ambient sound signal cancels the ambient sound that has directly penetrated the external auditory meatus from the exterior. The ambient sound is not included in the audio signal produced by cartilage conduction, and therefore the ambient sound picked up from the ambient sound microphone  31038  is not sent to the cartilage conduction equalizer  31038   a.    
     When headphones are being used, e.g., on the streets outdoors, the “ambient sound introduction mode” is used for preventing accidents or the like caused by unawareness of the sound of a vehicle approaching from the rear, preventing unawareness of being spoken to during headphone usage resulting in rude interactions with other parties, and for allowing ambient sound to be heard during headphone usage. Cartilage conduction is used in the present invention, and therefore audio sounds generated in the external auditory meatus can be satisfactorily heard at the same time when ambient sounds are introduced. Specifically, in the “ambient sound introduction mode,” ambient sounds picked up from the ambient sound microphone  31038  are mixed by the control unit  31039  without being phase-inverted, and are sent from the air conduction equalizer  31038   b  to the air conduction drive unit  31040   b . The ambient sounds picked up from the ambient sound microphone  31038  are not sent to the cartilage conduction equalizer  31038   a  and only an audio signal can be heard. An audio signal can thereby be heard by cartilage conduction while ambient sounds are electrically introduced without a passage hole or the like being structurally provided. 
     The details of the configuration of the electromagnetic vibrator  31025   a  are the same as those of the electromagnetic vibrating element  4324   a  of the forty-eighth embodiment shown in  FIG. 73 , and a description is therefore omitted. The details of the configuration of the electromagnetic speaker  31024   b  are the same as those of the electromagnetic air-conduction speaker  9925  of the one-hundred third embodiment shown in  FIG. 169 , and a description is therefore omitted. 
     The left-ear audio output part  31026  has the same configuration as that of the right-ear audio output part  31024  shown in  FIG. 199 , except for a power source unit  31048 , the operation unit  31009 , the short-range communication unit  31087 , and the ambient sound microphone  31038 , and is therefore omitted from the drawing. The cartilage conduction equalizer and the air conduction equalizer of the left-ear audio output part  31026  are connected to the control unit  31039  of the right-ear audio output part  31024  via a signal line between the left-ear audio output part  31026  and the right-ear audio output part  31024 . The power source unit  31048  supplies power to the stereo headphones  31081  overall, and therefore, power is not only supplied to the right-ear audio output part  31024 , but also to the left-ear audio output part  31026  via a signal line between the left-ear audio output part  31026  and the right-ear audio output part  31024 . 
       FIG. 200  is a flowchart showing the operation of the control unit  31039  of the one-hundred twenty-fourth embodiment in  FIG. 199 . The flow begins when a main power source is turned on by the operation unit  31009 . In step S 792 , an initial startup and a check of each unit function are performed. Subsequently, the cartilage conduction drive unit  31040   a  is turned on in step S 794 , the air conduction drive unit  31040   b  is turned on in step  796 , and the routine proceeds to Step S 798 . 
     In Step S 798 , a check is performed to determine whether the “normal mode” has been set, and if not, this means that the “noise-cancelling mode” or the “surrounding sound introduction mode (ambient sound introduction mode)” has been set, and the routine therefore advances to Step S 800 , the ambient sound microphone  31038  is turned on, and the routine advances to Step S 802 . When the routine has arrived at Step S 800  and the ambient sound microphone  31038  is already on, no action is performed in Step S 800 , and the routine proceeds to Step S 802 . In Step S 802 , a check is performed to determine whether the “noise-cancelling mode” has been set, and if so, the routine advances to Step S 804 , processing for inverting the input signal picked up by the ambient sound microphone  31038  is carried out, and in Step S 806 , volume adjustment processing for noise cancellation is performed. This volume adjustment sets a volume that conforms to the magnitude of the ambient sound assumed to arrive at the entrance to the external auditory meatus from the exterior. Subsequently, the input signal from the ambient sound microphone  31038  processed in Step S 808  is mixed with the air conduction audio signal, and the routine proceeds to Step S 812 . As described above, the processed input signal from the ambient sound microphone  31038  is not mixed with the audio signal for cartilage conduction. 
     On the other hand, in Step S 802 , when it has been confirmed that the “noise-cancelling mode” is not set, this means that the “surrounding sound introduction mode” is set and the routine advances to Step S 810 , and the volume adjustment processing is carried out for introducing surrounding sound to the input signal pickup up by the ambient sound microphone  31038 . Volume adjustment is set to a magnitude that does not mask the audio signal produced by cartilage conduction. Next, the routine advances to Step S 808 , the processed input signal from the ambient sound microphone  31038  is mixed with the air conduction audio signal, and the routine proceeds to Step S 812 . As described above, in this case as well, the processed input signal from the ambient sound microphone  31038  is not mixed with the audio signal for cartilage conduction. 
     In contrast to the above, in Step S 798 , when it has been confirmed that the “normal mode” is set, the routine advances to Step S 814 , the ambient sound microphone  31038  is turned off, and the routine proceeds directly to Step S 812 . When the routine arrives at Step S 814  and the ambient sound microphone  31038  is already off, no action is performed in Step S 814 , and the routine proceeds to Step S 812 . In Step S 812 , a check is performed to determine whether the power has been turned off by the operation unit  31009 , and if the power is not off, the routine returns to Step S 794 , and Step S 794  to Step S 814  are thereafter repeated as long as the power is not turned off. In this repetition, if the cartilage conduction drive unit  31040   a  and the air conduction drive unit  31040   b  are already on, no action is performed in Step S 794  and Step S 796 , and the routine proceeds to Step S 798 . On the other hand, when it has been confirmed in Step S 812  that the power has been turned off, the flow ends. 
     One-Hundred Twenty-Fifth Embodiment 
       FIG. 201  is an enlarged cross-sectional view and a block view of the internal configuration related to a one-hundred twenty-fifth embodiment according to an aspect of the present invention. The one-hundred twenty-fifth embodiment is also configured as stereo headphones, and the overall configuration can be understood in accordance with  FIG. 198  and is omitted from the drawing.  FIG. 201  shows an enlarged cross-sectional view of a right-ear audio output unit  32024  and a block view of the internal configuration. Also, the one-hundred twenty-fifth embodiment has much in common with the one-hundred twenty-fourth embodiment shown in  FIG. 199 , and therefore the same reference numerals are used for the same parts and a description thereof has been omitted unless otherwise required. 
     The one-hundred twenty-fifth embodiment of  FIG. 201  differs from the one-hundred twenty-fourth embodiment of  FIG. 199  in that the vibrations of an electromagnetic speaker  32024   b  are used as a cartilage conduction vibration source. Specifically, the electromagnetic speaker  32024   b  is supported by a vibration conductor  32027 , and the vibration conductor  32027  is embedded in and supported by the ear pad  31024   a.    
     In accordance with such a configuration, relative movement is generated between a first portion composed of the yoke  4324   h  or the like and a second portion composed of the vibration plate  9924   k  or the like when an audio signal is inputted from a drive unit  32040 , in the same manner as the one-hundred third embodiment of  FIG. 169 , and since the vibration plate  9924   k  is made to vibrate thereby, an air-conducted sound is generated from the electromagnetic speaker  32024   b . On the other hand, the first portion composed of the yoke  4324   h  also vibrates due to the counteraction of the vibrations of the second portion composed of the vibration plate  9924   k  or the like, and these vibrations are transmitted from the vibration conductor  32027  to the ear pad  31024   a . In the manner noted above, using the counteractions of vibrations of the electromagnetic speaker  32024   b  for generating air-conducted sound as the vibration source of cartilage conduction, it is possible to use both cartilage conduction and generation of air-conducted sound. In accompaniment therewith, there is a single drive control pathway from a control unit  32039  to the drive unit  32040  via an equalizer  32038 . 
     One-Hundred Twenty-Sixth Embodiment 
       FIG. 202  is an enlarged cross-sectional view and a block view of the internal configuration relating to a one-hundred twenty-sixth embodiment of an aspect of the present invention. The one-hundred twenty-sixth embodiment is also configured as stereo headphones, and the overall configuration can be understood in accordance with  FIG. 198  and is omitted from the drawing.  FIG. 202  shows an enlarged cross-sectional view of a right-ear audio output unit  33024  and a block view of the internal configuration. Also, the one-hundred twenty-sixth embodiment has much in common with the one-hundred twenty-fifth embodiment shown in  FIG. 201 , and therefore the same reference numerals are used for the same parts and a description thereof has been omitted unless otherwise required. 
     The one-hundred twenty-sixth embodiment of  FIG. 202  differs from the one-hundred twenty-fifth embodiment of  FIG. 201  in that, rather than an electromagnetic speaker, a piezoelectric bimorph element  33024   a  is used as the shared vibration source for air conduction and cartilage conduction. The structure of the piezoelectric bimorph element  33024   a  is the same as, e.g., the forty-first embodiment of  FIG. 64 , and a description is therefore omitted. In the one-hundred twenty-sixth embodiment of  FIG. 202 , both ends of the piezoelectric bimorph element  33024   a  are embedded in and supported by the inner edge of the facing ear pad  31024   a . Furthermore, a vibration plate  33027  is provided in the center part of the piezoelectric bimorph element  33024   a.    
     In accordance with such a configuration, the center part of the piezoelectric bimorph element  33024   a  vibrates with support at both ends of the ear pad  31024   a , whereby the vibration plate  33027  vibrates and air-conducted sound is generated. On the other hand, vibrations are transmitted to the ear pad  31024   a  from both ends of the piezoelectric bimorph element  33024   a  by the counteractions of the vibrations of the center part. In the manner noted above, using the counteractions of vibrations of the electromagnetic speaker  33024   a  for generating air-conducted sound as the vibration source of cartilage conduction, it is possible to use both cartilage conduction and generation of air-conducted sound. 
     One-Hundred Twenty-Seventh Embodiment 
       FIG. 203  is an enlarged cross-sectional view and a block view of the internal configuration relating to a one-hundred twenty-seventh embodiment of an aspect of the present invention. The one-hundred twenty-seventh embodiment is also configured as stereo headphones, and the overall configuration can be understood in accordance with  FIG. 198  and is omitted from the drawing.  FIG. 203  shows an enlarged cross-sectional view of a right-ear audio output unit  34024  and a block view of the internal configuration. Also, the one-hundred twenty-seventh embodiment has much in common with the one-hundred twenty-sixth embodiment shown in  FIG. 202 , and therefore the same reference numerals are used for the same parts and a description thereof has been omitted unless otherwise required. 
     The one-hundred twenty-seventh embodiment of  FIG. 203  differs from the one-hundred twenty-sixth embodiment of  FIG. 202  in that one end of a piezoelectric bimorph element  34024   a  serving as a shared vibration source for air conduction and cartilage conduction is embedded in and supported by the inner edge of the ear pad  31024   a , and the other end is capable of freely vibrating. A vibration plate  34027  is provided to this freely vibrating end. 
     In accordance with such a configuration, the freely vibrating end of the piezoelectric bimorph element  34024   a  vibrates with support at the other end by the ear pad  31024   a , whereby the vibration plate  33027  vibrates and air-conducted sound is generated. On the other hand, vibrations are transmitted to the ear pad  31024   a  from the other end of the piezoelectric bimorph element  34024   a  by the counteractions of the vibrations of the freely vibrating end. In the manner noted above, using the counteractions of vibrations of the electromagnetic speaker  34024   a  for generating air-conducted sound as the vibration source of cartilage conduction, it is possible to use both cartilage conduction and generation of air-conducted sound in the same manner as the one-hundred twenty-sixth embodiment of  FIG. 202 . 
     The implementation of the features of the present invention described above is not to be limited to the aspects in the above embodiments, and implementation is also possible using other aspects as well, wherever it is possible to benefit from the advantages thereof. Also, the various features of different embodiments can be combined, as appropriate. For example, in the one-hundred twenty-fourth embodiment shown in  FIG. 199 , introduction of ambient sound is determined by electrically switching, but it is also possible use a configuration in which a passage hole is provided in the manner of the ninety-first embodiment shown in  FIG. 141  and the passage hole is mechanically opened and closed. 
     One-Hundred Twenty-Eighth Embodiment 
       FIG. 204  is a system configuration diagram of a one-hundred twenty-eighth embodiment according to an aspect of the present invention. The one-hundred twenty-eighth embodiment is configured as a mobile telephone system comprising a mobile telephone  35601  and a touch pen-type handset  35001 , of which the latter has a cartilage conduction unit  35024  and is used also for touch panel input. The two can communicate with each other by near-field communication using a radio wave  6585  of a communication system such as Bluetooth™. The mobile telephone system of the one-hundred twenty-eighth embodiment has much in common with the sixty-ninth embodiment in  FIG. 101 ; therefore, common parts are identified by the same reference numerals as in  FIG. 101 , and no overlapping description will be repeated unless necessary. 
     The touch pen-type handset  35001  of the one-hundred twenty-eighth embodiment shown in  FIG. 204  allows touch pen input by touches with the touch pen unit  35001   a  on a touch panel provided in a large-screen display unit  205  of the mobile telephone  35601 . Moreover, as mentioned above, the touch pen-type handset  35001  has, at its upper end, the cartilage conduction unit  35024  and, in a lower part, a microphone  35023 , and thus can be used as a wireless handset. When using it as a handset, a user hears sound from the other side with the cartilage conduction unit  35024  put on the tragus or the like, and speaks to the microphone  35023  located near the mouth. In this way, the advantages of cartilage conduction can be exploited in a similar manner as in other embodiments. 
     The touch pen-type handset  35001  of the one-hundred twenty-eighth embodiment includes a near-field communication unit  6546  for communication with the mobile telephone  35601 , and is controlled comprehensively by a control unit  6539 . An incoming-call vibrator  6525  makes the touch pen-type handset  35001 , as in a state stuck in a chest pocket, vibrate to notify an incoming call. Using vibration of the cartilage conduction unit  35024  as an incoming-call vibrator eliminates the need to provide the incoming-call vibrator  6525  as a vibration source. 
     An operation unit  6509  includes a call start button  6509   a  operated to start an outgoing call or to respond to an incoming call, a call end button  6509   b  for ending a call, and a select button  5609   c  for selecting a call destination. A display unit  6505  includes a plurality of indicator lamps  6505   a ,  6505   b , and  6505   c.    
     When starting an outgoing call, each time a user presses the select button  5609   c , one after the next of the indicator lamps  6505   a ,  6505   b , and  6505   c  is lit, one at a time, so that, by selecting which lamp to light, the user can select one of previously set call destinations. The selection causes the corresponding data, such as a telephone number, stored in a storage unit  6537  (see  FIG. 205 ) to be read out, in preparation for a call originating operation. When the user chooses to originate a call to a call destination other than the previously set ones, he can call up a telephone directory on the large-screen display unit  205  of the main body of the mobile telephone  35601  and then touch an entry on the list with the touch pen unit  35001   a  to select a call destination. Having thus selected a call destination, the user can start a call by pressing the call start button  6509   a . The number of previously set call destinations can be increased by adopting, in addition to the patterns in which only one of the indicator lamps  6505   a ,  6505   b , and  6505   c  is lit respectively, also patterns in which two of them are lit together, namely in combinations of  6505   a  and  6505   b ,  6505   b  and  6505   c , and  6505   a  and  6505   c  respectively. 
     On the other hand, when an incoming call is received from a previously set call destination, the lamps are lit in one of the above-mentioned patterns. Thus, based on the pattern in which the lamps are lit, the user can know who is calling. When an incoming call is received from a call destination other than the previously set ones, this is indicated with all the indicator lamps  6505   a ,  6505   b , and  6505   c  lit. To check out who is calling, the user can see an indication on the large-screen display unit  205  of the main body of the mobile telephone  35601 . 
     To previously set a call destination, the user calls up a telephone directory on the large-screen display unit  205  of the main body of the mobile telephone  35601 , and operates the select button  5609   c  to select the pattern to be assigned. The user then touches with the touch pen unit  35001   a  a telephone number in the telephone directory which the user wants to set (e.g., “Ishida”  35205  shown on the large-screen display unit  205 ), and then presses the call start button  6509   a  and the call end button  6509   b  simultaneously to fix the setting. In this way, the data, such as the telephone number, received from the near-field communication unit  6546  is stored in the storage unit  6537 , in association with a display pattern of the indicator lamps  6505   a ,  6505   b , and  6505   c , which function as the display unit  6505 . 
       FIG. 205  is a system block diagram of the one-hundred twenty-eighth embodiment shown in  FIG. 204 .  FIG. 205  too has much in common with  FIG. 102 , which shows the sixty ninth embodiment; therefore, common parts are identified by the same reference numerals as in  FIG. 102 , and no overlapping description will be repeated unless necessary. Likewise, such parts as are shown also in  FIG. 204  are identified by the same reference numerals, and no overlapping description will be given unless necessary. In  FIG. 205 , in explanation of the one-hundred twenty-eighth embodiment, a touch panel  35068  is illustrated in the large-screen display unit  205  of the mobile telephone  35601 , and a control unit is assigned the reference numeral  35239 . In the touch pen-type handset  35001 , a sound processing unit  35040  processes an audio signal collected by the microphone  35023  and transmits the result from the near-field communication unit  6546  to the mobile telephone  35601 ; the sound processing unit  35040  also makes a drive unit  35039  vibrate the cartilage conduction unit  35024  based on an audio signal, conveying the sound from the other side, that is transmitted from the mobile telephone  35601  and received by the near-field communication unit  6546 . 
     Here, a supplemental description will be given of the relationship between the touch panel  35068  in the large-screen display unit  205  of the mobile telephone  35601  and the touch pen-type handset  35001 . With no touch input for a predetermined period, the large-screen display unit  205  enters a power-saving state, turning off a backlight (not shown) and disabling the touch panel  35068 . The power-saving state occurs in a so-called standby state, i.e., a state in which the mobile telephone  35601  is put in a bag or in a pocket. When an incoming call is received in the power-saving state, the incoming-call vibrator  6525  of the touch pen-type handset  35001  vibrates, and in addition the touch pen-type handset  35001  functions to permit a user to engage in the call without taking out the mobile telephone  35601 . 
     On the other hand, when the large-screen display unit  205  is not in the power-saving state, and thus the backlight is lit and the touch panel  35068  is in an operating state, touch input is possible by touches with the touch pen-type handset  35001 . When an incoming call is received in this state, basically the user engages in the call by using the main body of the mobile telephone  35601 . Even in this case, if, due to ambient noise or the like, the user finds difficulty engaging in the call, he can, by manual operation, switch to use the touch pen-type handset  35001 . 
       FIG. 206  is a flow chart showing the function of the control unit  35239  of the mobile telephone  35601  of the one-hundred twenty-eighth embodiment. The flow in  FIG. 206  focuses on operation for functions for coordination with the touch pen-type handset  35001  on receiving an incoming call and functions for inputting a telephone directory entry to the touch pen-type handset  35001  for setting a call destination; in reality, the mobile telephone  35601  involves operation of the control unit  35239  other than that shown in the flow in  FIG. 206 . The control unit  35239  can additionally perform any of the functions described in connection with other various embodiments, but these functions too are omitted from illustration and description to avoid complication. 
     The flow in  FIG. 206  starts when the main power to the mobile telephone  35601  is turned on. In Step S 822 , a start-up procedure is gone through, checks are made on the functions of different blocks, and display is started on the large-screen display unit  205  of the mobile telephone  35601 . Next, in Step S 824 , whether or not an incoming call is being received is checked. If an incoming call is being received, then, in Step S 826 , whether or not the touch panel  35068  is in the power-saving state is checked. If not, then, in Step S 827 , whether or not an incoming videophone call is being received is checked. If not, then in Step S 828 , the incoming call is indicated with a ringtone from the main body of the mobile telephone  35601 , or by the incoming-call vibrator. Then, in Step S 830 , a responding operation on the operation unit  209  of the main body of the mobile telephone  35601  is waited for, and when a responding operation is done, the flow advances to Step S 832 . 
     In Step S 832 , based on an operation on the operation unit  209  of the mobile telephone  35601 , or based on receipt of a signal representing an operation on the operation unit  6509  of the touch pen-type handset  35001 , it is checked whether or not a manual operation for selecting the touch pen-type handset  35001  has been done. If no operation for selecting the touch pen-type handset  35001  is detected, then, in Step S 834 , a microphone  223  and an earphone  213  of the main body of the mobile telephone  35601  are turned on, and communication by the main body of the mobile telephone  35601  is started. Next, in Step S 836 , whether or not an operation for ending a call is done is checked, and if an operation for ending a call is detected, the flow advances to Step S 838 . On the other hand, if, in Step S 836 , no operation for ending a call is detected, the flow returns to Step S 832  so that thereafter, so long as no operation for ending a call is detected, Step S 832  through S 836  are repeated. During the repetition, if the microphone  223  and the earphone  213  of the mobile telephone  35601   p  are already on, nothing is done in Step S 834 . 
     On the other hand, if, in Step S 826 , the touch panel  35068  is detected being in the power-saving state, or if, in Step S 827 , an incoming videophone call is detected, then, in Step S 840 , the incoming call is indicated by the incoming-call vibrator  6525  of the touch pen-type handset  35001 . Then, in Step S 842 , a responding operation on the operation unit  6509  (call start button  6509   a ) of the touch pen-type handset  35001  is waited for, and when a responding operation is done, the flow advances to Step S 844 . 
     In Step S 844 , the microphone  223  and the earphone  213  of the main body of the mobile telephone  35601  are turned off, and then, in Step S 846 , the microphone  35023  of the touch pen-type handset  35001  is turned on. Further, in Step S 848 , the cartilage conduction unit  35024  is turned on. Then, in Step S 850 , an operation on the operation unit  6509  (call end button  6509   b ) is waited for, and when an operation for ending the call is done, the flow advances to Step S 838 . 
     Incidentally, during the above-mentioned repetition of Steps S 832  through S 836 , if, in Step S 832 , a manual operation for selecting the touch pen-type handset  35001  is detected, then the flow advances to Step S 844 , so that the call that has been conducted on the main body of the mobile telephone  35601  is thereafter switched to a call conducted on the touch pen-type handset  35001 . In this way, when a user finds difficulty engaging in a call on the main body of the mobile telephone  35601 , at any time during the call, he can switch to the touch pen-type handset  35001 . 
     In Step S 838 , it is checked whether or not a touch with the touch pen-type handset  35001  has been made on a telephone directory in a state where, with a view to previously setting a call destination, the telephone directory is displayed on the large-screen display unit  205  of the mobile telephone  35601  and an indicator pattern to be assigned is selected with the select button  5609   c . If such a touch is detected, the flow proceeds to Step S 852 , namely “Input Phone Directory Entry To Handset”. This process involves, among others, detecting a touched position, identifying a selected call destination, transmitting an identified telephone directory entry to the touch pen-type handset  35001 , and fixing a setting by detecting simultaneous pressing of the call start button  6509   a  and the call end button  6509   b . To set a plurality of call destinations, a user can then touch the next call destination and repeat the same process. On completion of the process in Step S 838 , the flow advances to Step S 854 . If, in Step S 838 , no touch for input of a telephone directory entry is detected, the flow advances directly to Step S 854 . 
     In Step S 854 , whether or not the main power to the touch pen-type handset  35001  has been turned off is checked, and if not, the flow returns to Step S 824  so that thereafter, so long as the main power is not detected having been turned off in Step S 854 , Step S 824  through S 854  are repeated. On the other hand, if, in Step S 854 , the main power is detected having been turned off, the flow ends. 
     Though omitted from  FIG. 206  to avoid complication, if, in Step S 830  or S 842 , no responding operation is done for a predetermined period or longer, or if response is refused and an operation for ending a call is done, the flow jumps to Step S 838 . 
     While the flow in  FIG. 206  focuses on functions for handling an incoming call, functions for handling an outgoing call are basically similar. Specifically, reading Step S 824  as “Outgoing Call?” and reading each of Steps S 830  and S 842  as “Other Side Responded” will enable one to understand the functions for handling an outgoing call. For the handling of an outgoing call, Steps S 828  and S 840 , namely incoming call notification, are omitted. 
     One-Hundred Twenty-Ninth Embodiment 
       FIG. 207  is a system configuration diagram of a one-hundred twenty-ninth embodiment according to an aspect of the present invention. The one-hundred twenty-ninth embodiment is configured as a mobile telephone system comprising a mobile telephone  35601  and a clinical thermometer-type handset  36001 , of which the latter has a cartilage conduction unit  35024  and is used also for touch panel input. The two can communicate with each other by near-field communication using a radio wave  6585  of a communication system such as Bluetooth™. The mobile telephone system of the one-hundred twenty-ninth embodiment has much in common with the one-hundred twenty-eighth embodiment shown in  FIG. 204 ; therefore, common parts are identified by the same reference numerals as in  FIG. 204 , and no overlapping description will be repeated unless necessary. The detailed configuration of the system is similar to that in the block diagram in  FIG. 205 , which shows the one-hundred twenty-eighth embodiment. 
     The one-hundred twenty-ninth embodiment shown in  FIG. 207  differs from the one-hundred twenty-eighth embodiment in  FIG. 204  in that the handset that is usable also for touch panel input is configured as a clinical thermometer-type handset  36001  that is flat. On a flat face, a small display screen  66505  is provided as a display unit. The small display screen  66505  provides clear display of the other side&#39;s telephone number, etc. The display of the telephone number, etc. can be used to allow selection of a call destination for an outgoing call, to indicate an incoming call, or to check a telephone directory entry to be set as a call destination. The small display screen  66505  can further be used to display explanations of various methods of use, such as a method of use as a cartilage conduction handset, and to indicate the power drain status of a power supply unit  6548 , etc. 
     The features of the present invention in the embodiments described above are not limited to those specific embodiments; they can be implemented in any other embodiment so long as they provide their advantages. Various features from different embodiments can be implemented in any appropriate combination. For example, the clinical thermometer-type handset  36001  of the one-hundred twenty-ninth embodiment shown in  FIG. 207  provides a configuration that is useful even when its touch pen function is not used. The touch pen-type handset  35001  and the clinical thermometer-type handset  36001  in the one-hundred twenty-eighth embodiment in  FIG. 204  and the one-hundred twenty-ninth embodiment in  FIG. 207  respectively, of which both are also usable for touch panel input, can be configured such that they can be stored inside a body of, or inside a cover for covering, the mobile telephone  35601 . 
     The touch pen-type handset  35001  and the clinical thermometer-type handset  36001  in the one-hundred twenty-eighth embodiment in  FIG. 204  the one-hundred twenty-ninth embodiment in  FIG. 207  respectively, of which both are also usable for touch panel input, can be furnished with not only functions for handling outgoing and incoming calls but also functions of an independent telephone, like the ultra-compact mobile telephone  6501  in the sixty ninth embodiment shown in  FIG. 101 . Conversely, the one-hundred twenty-eighth embodiment shown in  FIG. 204  and the one-hundred twenty-ninth embodiment shown in  FIG. 207  can be simplified by omitting the microphone  35023 , in which case sound can be collected by the microphone  223  of the mobile telephone  35601 . Although the advantages of cartilage conduction cannot be obtained, even with a configuration where the cartilage conduction unit is replaced with an ordinary air-conduction speaker, it is possible to obtain the benefits of a handset that doubles as a touch pen. 
     One-Hundred Thirtieth Embodiment 
       FIG. 208  is a schematic diagram of a one-hundred thirtieth embodiment according to one aspect of the present invention, which is configured as stereo earphones. The stereo earphones are configured symmetrically left to right to have two similarly configured units. Therefore, only one unit will be described below as an “earphone”.  FIG. 208(A)  is an exterior front view of the earphone as seen from an inner side thereof (the side attached to an ear), where major components that are invisible from outside are indicated by broken lines. The earphone of the one-hundred thirtieth embodiment, like that of the one-hundred ninth embodiment in  FIG. 182  for instance, has a cartilage conduction unit  36024  which is formed of an elastic member with strong resilience and of which a lower part is coupled to a sheath part  36024   b . An upper end part of a piezoelectric bimorph element  36025  is embedded directly in, and firmly fixed to, the lower part of the cartilage conduction unit  36024  inside the sheath part  36024   b  without touching its inner wall. Through a hole in a lower part of the sheath part  36024   b , a connection cable  36024   d  is led out. 
     The cartilage conduction unit  36024  in the earphone of the one-hundred thirtieth embodiment in  FIG. 208  is, in a similar manner as shown in  FIG. 182(A)  in connection with the one-hundred ninth embodiment, held in a space between the inner side of the tragus and the antihelix. Here, the sheath part  36024   b  hangs down below the ear, that is, in a similar manner as shown in  FIG. 182(A) , from the cavum conchae through the intertragic notch. 
     The one-hundred thirtieth embodiment in  FIG. 208  differs from the one-hundred ninth embodiment in  FIG. 182  and other embodiments in that, inside the cartilage conduction unit  36024 , a ring-shaped vibration plate (diaphragm)  36027  for generating air conduction sound is arranged which vibrates without making contact with the cartilage conduction unit  36024 , and in that the vibration plate  36027  is supported directly on the upper end of the piezoelectric bimorph element  36025  which penetrates the lower part of the cartilage conduction unit  36024 . In  FIG. 208(A) , an inner passage hole  36024   a  and an outer passage hole  36024   c , the latter having a smaller diameter than the former, are visibly illustrated. As mentioned above, the vibration plate  36027  is invisible from outside. 
       FIG. 208(B)  is a sectional view of a part in  FIG. 208(A)  where the piezoelectric bimorph element  36025  is located (a sectional view along line B 1 -B 1  in later-described  FIG. 208(C) , which is a sectional view 90 degrees rotated from  FIG. 2080(B) ), and there, such parts as are shown also in  FIG. 208(A)  are identified by the same reference numerals. As will be clear from  FIG. 208(B) , a lower part of the cartilage conduction unit  36024  is extended to form a connection part  36024   h , and the sheath part  36024   b  is fitted around the connection part  36024   h  so as to cover it. This permits the sheath part  36024   b  to securely couple with the cartilage conduction unit  36024 . On the other hand, an upper end part of the piezoelectric bimorph element  36025  is inserted inside the connection part  36024   h  so as to penetrate it. This protects the piezoelectric bimorph element  36025 , and permits a lower end part of the piezoelectric bimorph element  36025  to vibrate inside the sheath part  36024   b  without making contact with it. Thus, a reaction of the vibration of the lower part of the piezoelectric bimorph element  36025  conducts to the cartilage conduction unit  36024 , achieving satisfactory cartilage conduction. 
     As indicated by dash-and-dot lines in  FIG. 208(B) , inside the cartilage conduction unit  36024 , the vibration plate  36027  is arranged which vibrates without touching the unit, and is supported on an inner side (the side attached to the ear) of the upper end of the piezoelectric bimorph element  36025  which penetrates the connection part  36024   h . The reason that the vibration plate  36027  is ring-shaped is to direct outside sound to the earhole. Thus, as the piezoelectric bimorph element  36025  vibrates, the vibration plate  36027  generates air-conduction sound. In this way, middle- to low-register sound is mainly covered by cartilage conduction, high-register sound is mainly covered by air-conduction sound from the vibration plate  36027 . 
     As mentioned above,  FIG. 208(C)  is a sectional view 90 degrees rotated from  FIG. 208(B) , and there, such parts as are shown also in  FIGS. 208(A)  and (B) are identified by the same reference numerals. In  FIG. 208(C) , the left side is the side attached to the ear (inner side). As will be clear from  FIG. 208(C) , in a cavity inside the cartilage conduction unit  36024 , the vibration plate  36027  is arranged which vibrates without touching the unit&#39;s inner wall, and is supported directly on the upper end of the piezoelectric bimorph element  36025  which penetrates the connection part  36024   h . As will be clear from  FIG. 208(C) , compared with the diameter of the inner passage hole  36024   a  facing the ear, the diameter of the outer passage hole  36024   c  facing outside is smaller. Thus, the inner passage hole  36024   a , which is located on the earhole side of the vibration plate  36027 , is wider open than the outer passage hole  36024   c , which is located outward of the vibration-conducting plate  36027 . This permits the air-conduction sound from the vibration plate  36027  to be effectively directed to the earhole. To that end, the inner passage hole  36024   a  is preferably given as large a diameter as possible so long as no problem arises in terms of mechanical strength or protection of the vibration plate. On the other hand, the outer passage hole  36024   c  is preferably given as small a diameter as possible so long as no problem arises in terms of introduction of outside sound. In  FIG. 208(C) , to avoid complication, the connection cable  36024   d  is omitted from illustration. 
     As mentioned above, the vibration plate  36027  is ring-shaped so as not to prevent the outside sound that has entered through the outer passage hole  36024   c  from passing through the inner passage hole  36024   a  into the earhole. However, so long as, inside the cavity in the cartilage conduction unit  36024 , a gap through which the outside sound that has entered through the outer passage hole  36024   c  can pass on to the inner passage hole  36024   a  (e.g., a gap between the circumference of the vibration plate  36027  and the inner wall of the cavity) can be secured, the vibration plate  36027  does not have to be ring-shaped but may be disc-shaped, with no hole. In a case where a hole is provided to allow passage of outside sound, its position is not limited to at the center of the vibration plate, nor is its shape limited to circular; more than one hole may be provided, and a large number of holes may be provided in a honeycomb array. 
     One-Hundred Thirty-First Embodiment 
       FIG. 209  is a schematic diagram of a one-hundred thirty-first embodiment according to one aspect of the present invention, which is configured as stereo earphones.  FIGS. 209(A)  to (C) showing the one-hundred thirty-first embodiment have very much in common with  FIGS. 208(A)  to (C) showing the one-hundred thirtieth embodiment; therefore, common parts are identified by the same reference numerals, and no overlapping description will be repeated unless necessary. 
     The one-hundred thirty-first embodiment in  FIG. 209  differs from the one-hundred thirtieth embodiment in  FIG. 208  is that, as will be clear from  FIG. 209(C) , the vibration plate  37027  is held in close contact with the inner side of a part of the cartilage conduction unit  37024  around the outer passage hole  37024   c , via a soft material  37024   t . As in the one-hundred thirtieth embodiment in  FIG. 208 , the vibration plate  37027  makes contact with the upper end of the piezoelectric bimorph element  36025  penetrating the connection part  36024   h  to achieve direct conduction of the plate&#39;s vibration. 
     The configuration of the one-hundred thirty-first embodiment in  FIG. 209  may slightly restrict the freedom of the vibration plate  37027  to vibrate, but, owing to the vibration plate  37027  being supported also on the cartilage conduction unit  37024 , offers increased structural strength, making the earphones, when dropped by mistake, less prone to breakage as by the vibration plate  37027  coming off the piezoelectric bimorph element  36025 . 
     In the configuration of the one-hundred thirty-first embodiment in  FIG. 209 , so long as no problem arises in terms of the restriction on the freedom of the vibration plate  37027  to vibrate, the vibration plate  37027  may be held in close contact directly with the inner side of a part of the cartilage conduction unit  37024  around the outer passage hole  37024   c , i.e., without the soft material  37024   t  interposed. In that case, the degree of elasticity of the cartilage conduction unit  37024  is determined based on a tradeoff between how well the cartilage conduction unit  37024  should, when worn, maintain its shape to achieve satisfactory cartilage conduction and how far the freedom of the vibration plate  37027  to vibrate can be restricted. On the other hand, reducing the thickness of the outer passage hole  37024   c  helps alleviate the degree of restriction on the freedom of the vibration plate  37027  to vibrate. 
     One-Hundred Thirty-Second Embodiment 
       FIG. 210  is a schematic diagram of a one-hundred thirty-second embodiment according to one aspect of the present invention, which is configured as stereo earphones.  FIGS. 210(A)  to (C) showing the one-hundred thirty-second embodiment have very much in common with  FIGS. 208(A)  to (C) showing the one-hundred thirtieth embodiment; therefore, common parts are identified by the same reference numerals, and no overlapping description will be repeated unless necessary. 
     A first difference of the one-hundred thirty-second embodiment in  FIG. 210  from the one-hundred thirtieth embodiment in  FIG. 208  is that, as will be clear from  FIG. 210(B) , the cartilage conduction unit  38024  and the sheath part  38024   b  are formed integrally out of a hard material. A second difference of the one-hundred thirty-second embodiment from the one-hundred thirtieth embodiment is that a lower end part of the piezoelectric bimorph element  38025  is supported on the inner side of a lower end part of the sheath part  38024   b  so that an upper end part of the piezoelectric bimorph element  38025  can vibrate freely inside the sheath part  38024   b  without making contact with the inner wall of the sheath part  38024   b  or of the cartilage conduction unit  38024 . The vibration plate  38027  is supported on an upper end part of the piezoelectric bimorph element  38025  which can thus vibrate freely. The vibration plate  38027  thus vibrates inside the cavity in the cartilage conduction unit  38024  to generate air-conduction sound. In the one-hundred thirty-second embodiment, the cartilage conduction unit  38024  is formed of a hard material, and accordingly the cartilage conduction unit  38024  itself (e.g., the front face around the inner passage hole  36024   a ) generates air-conduction sound, augmenting high-register sound. On the other hand, due to the air-conduction sound generated by the sheath part  38024   b  and the cartilage conduction unit  38024 , sound is more likely to leak in the ambience. 
     A third difference of the one-hundred thirty-second embodiment from the one-hundred thirtieth embodiment is that, as will be clear from  FIG. 210(C) , at an entrance part of the inner passage hole  36024   a  and the outer passage hole  36024   c  respectively, protective meshes  38024   u  and  38024   v  are provided. This makes it possible, without preventing passage of outside sound, to prevent entry of foreign matter into the cavity in the cartilage conduction unit  38024  and the resulting inconveniences such as failure of the vibration plate  38027  etc. As will be clear from  FIG. 210(A) , the protective mesh  38024   u  is visible from outside. In a case where the outer passage hole  36024   c  is sufficiently small, the protective mesh  38024   v  may be omitted. With a configuration in which a protective mesh  38024   u  is provided at the inner passage hole  38024   a  to protect the cavity in the cartilage conduction unit  38024 , the inner passage hole  36024   a  can be given a diameter larger than that of the vibration plate  38027 ; for example, a bullhorn-like shape can be adopted to effectively direct the air-conduction sound from the vibration plate  38027  to the earhole. 
     A structure in which a protective mesh is provided at an entrance part of a passage hole is not limited to the one-hundred thirty-second embodiment; a protective mesh may be provided in the one-hundred thirtieth and one-hundred thirty-first embodiments described previously, and also in any of the embodiments described later. In that case, if the cartilage conduction unit is formed of an elastic member, the protective mesh too is given an elastic structure. 
     One-Hundred Thirty-Third Embodiment 
       FIG. 211  is a schematic diagram of a one-hundred thirty-third embodiment according to one aspect of the present invention, which is configured as stereo earphones.  FIGS. 211(A)  to (C) showing the one-hundred thirty-third embodiment have very much in common with  FIGS. 208(A)  to (C) showing the one-hundred thirtieth embodiment; therefore, common parts are identified by the same reference numerals, and no overlapping description will be repeated unless necessary. 
     A first difference of the one-hundred thirty-third embodiment in  FIG. 211  from the one-hundred thirtieth embodiment in  FIG. 208  is that, as shown in  FIGS. 211(B)  and (C), an upper end part of the piezoelectric bimorph element  39025  is supported on (without penetrating) the connection part  39024   h  of the cartilage conduction unit  39024 , which is an elastic member, and in addition a lower end part of the piezoelectric bimorph element  39025  is supported on the inner side of a lower end part of the sheath part  39024   b . While anchoring the lower end part of the piezoelectric bimorph element  39025  results in different vibration characteristics, the upper end part now has a steady fulcrum for vibration; this increases the amplitude of the cartilage conduction unit  39024 . 
     A second difference of the one-hundred thirty-third embodiment in  FIG. 211  from the one-hundred thirtieth embodiment in  FIG. 208  is that, as shown in  FIGS. 211(B)  and (C), a part of the sheath part  39024   b  constitutes an extension part  39024   w  which penetrates the cartilage conduction unit  39024  upward, and the vibration plate  39027  is supported on the extension part  39024   w . Supporting a lower end part of the piezoelectric bimorph element  39025  permits the vibration of the sheath part  39024   b  to conduct; this is exploited to make the vibration plate  39027  vibrate inside the cavity in the cartilage conduction unit  39024 ; the air-conduction sound generated as a result helps augment high-register sound. 
     In the one-hundred thirtieth to one-hundred thirty-third embodiments, a piezoelectric bimorph element is used as a vibration source for the cartilage conduction unit and the vibration plate. However, the vibration source is not limited to a piezoelectric bimorph element; instead, an electromagnetic vibrating element such as the electromagnetic vibrating element  4324   a  in the forty-eighth embodiment in  FIG. 73  may be adopted and arranged in the cavity in the cartilage conduction unit. In that case, as in the one-hundred twenty-fifth embodiment in  FIG. 201 , of a pair of members constituting an electromagnetic vibrating element that vibrate relative to each other, one (e.g., the part constituting the voice coil bobbin  4324   k  in  FIG. 73 ) is used to make the vibration plate vibrate, and the other (e.g., the part constituting the yoke  4324   h  in  FIG. 73 ), which receives a reaction from the former, is held inside the cavity in the cartilage conduction unit to obtain cartilage conduction. Also in a case where an electromagnetic vibrating element is adopted as a vibration source, a gap is secured between the electromagnetic vibrating element and the inner wall of the cavity in the cartilage conduction unit so as not to prevent the outside sound that has entered through the outer passage hole from passing through the inner passage hole into the earhole. 
     The various features of the present invention in the embodiments described above are not limited to those specific embodiments; they can be implemented in any other embodiment so long as they provide their advantages. Features from different embodiments can be combined into a single embodiment. For example, the protective mesh in the one-hundred thirty-second embodiment in  FIG. 210  can be adopted in the one-hundred twenty-fourth to one-hundred twenty-seventh embodiments shown in  FIGS. 198 to 203 . A configuration in which, as in the one-hundred thirty-second embodiment in  FIG. 210 , the cartilage conduction unit is formed of a hard material can be adopted also, for example, the one-hundred thirtieth embodiment in  FIG. 208 . However, in the one-hundred thirtieth embodiment, which is so configured that the vibration of the piezoelectric bimorph element is not conducted to the sheath part, a layer of a vibration insulating material, like the elastic body  5165   a  adopted in the fifty-fifth embodiment in  FIG. 83 , is interposed between the cartilage conduction unit and the sheath part. 
     One-Hundred Thirty-Fourth Embodiment 
       FIG. 212  is a system configuration diagram of a one-hundred thirty-fourth embodiment according to one aspect of the present invention. The one-hundred thirty-fourth embodiment is configured as a mobile telephone system comprising a mobile telephone  35601  and a wrist watch-type handset  40001 , and the two can communicate with each other by near-field communication using a radio wave  6585  of a communication system such as Bluetooth™. The mobile telephone system of the one-hundred thirty-fourth embodiment has much in common with the one-hundred twenty-eighth embodiment in  FIG. 204 ; therefore, common parts are identified by the same reference numerals as in  FIG. 204 , and no overlapping description will be repeated unless necessary. 
     In the one-hundred thirty-fourth embodiment shown in  FIG. 212 , the wrist watch-type handset  40001  includes a watch body  40001   a  and a belt part  40001   b . The watch body  40001   a  includes a watch display unit  40005 , which displays time in an ordinary fashion and also displays various kinds of information as will be described later. The watch display unit  40005  includes a variable-directivity microphone  40023 , which will be described later, and a speaker  40013 . Thus, even with the mobile telephone  35601  put in a pocket for instance, near-field communication with the mobile telephone  35601  permits a user to conduct a call while viewing the wrist watch-type handset  40001 . The watch display unit  40005  further includes a camera unit  40017 , which can shoot the face of the user himself viewing the watch display unit  40005 , while the face of the person at the other side is displayed on the watch display unit  40005 . Thus, user can conduct a videophone session. In a videophone session, the directivity of the variable-directivity microphone  40023  is so set as to collect sound from in front of the watch display unit  40005 . 
     The watch display unit  40005  further includes a display-side cartilage conduction unit  40024   a , which conducts vibration for cartilage conduction to the surface of the watch display unit  40005 . Thus, by putting the watch display unit  40005  on an ear in a posture as will be described later, a user can hear sound from the other side by cartilage conduction. At this time, the directivity of the variable-directivity microphone  40023  is so switched as to collect sound from the direction of the elbow of the arm (typically, the left arm) on which the wrist watch-type handset  40001  is worn, and thus the user can conduct a call in the posture described later. The variable-directivity microphone  40023  achieves the switching of directivity with a configuration as in the one-hundred sixth embodiment in  FIG. 176 . 
     On the other hand, the belt part  40001   b  includes a belt-side cartilage conduction unit  40024   b , which conducts vibration for cartilage conduction to the entire belt part  40001   b . Thus, by putting the belt part  40001   b  to an ear in another posture as will be described later, the user can hear sound from the other side by cartilage conduction, and can conduct a call in a similar manner as described above. Vibration conducts from the belt part  40001   b  to the wrist, and thus even without putting the belt part  40001   b  directly on the ear, by putting the hand to which the vibration conducts (such as the palm or the forefinger) on the ear cartilage, the user can hear the other side by cartilage conduction. Along the belt part  40001   b , an antenna  6545   a  of the near-field communication unit is provided so as to be wound around the wrist. 
       FIG. 213  shows screens that are displayed on the watch display unit  40005  in the one-hundred thirty-fourth embodiment shown in  FIG. 212  to present explanations of postures for conducting a call. These screens are displayed every time the power switch of the wrist watch-type handset  40001  is turned on; if this is annoying, a setting is also possible such that their display is skipped.  FIG. 213(A)  shows a posture for a videophone session, explaining a posture in which a user can conduct a videophone session while viewing the watch display unit  40005  with the wrist watch-type handset  40001  put in a pocket for instance. 
       FIG. 213(B)  illustrates a posture for a cartilage conduction call, showing a posture in which a user raises the arm on which he is wearing the wrist watch-type handset  40001  across the face to put the watch display unit  40005  on the ear on the opposite side. In  FIG. 213(B) , the user is wearing the wrist watch-type handset  40001  on his left arm, and thus puts the watch display unit  40005  on the right ear. In this call-conducting posture, vibration conducts from the inner passage hole  36024   a  to the ear cartilage, and thus the user can hear sound from the other side by satisfactory cartilage conduction; the user can also deliver his voice, which is collected by the variable-directivity microphone  40023  having its directivity so switched as to collect sound from the direction of the elbow, to the other side. Taking this posture turns off the camera unit  40017 , the speaker  40013 , and the watch display unit  40005 . The automatic turning-off here is achieved by an acceleration sensor  40049  (see  FIG. 215 ) detecting the postures shown in  FIGS. 213(A)  and (B). 
       FIG. 214  shows screens presenting explanations of other call-conducting postures that are displayed on the watch display unit  40005  in a similar manner as those in  FIG. 213 .  FIG. 214(A)  shows a posture which results from the user rotating the wrist by 90 degrees from the posture in  FIG. 213(B)  to bring up the watch display unit  40005  and in which the user puts the belt part  40001   b  to the ear. In this posture, the watch display unit  40005  does not touch the ear, and thus its surface is saved from being soiled with sebum or the like. In this posture, vibration conducts from the sheath part  36024   b  to the ear cartilage. In a similar manner as described above, the voice of the user himself is collected by the variable-directivity microphone  40023  that has its directivity so switched as to collect sound from the direction of the elbow. 
       FIG. 214(B)  shows a call-conducting posture in which a user puts one arm, as if a pillow, behind the head and in which the user puts the palm side of the belt part  40001   b  on the ear on the same side as the arm on which he is wearing the wrist watch-type handset  40001  (in the diagram, the left arm on the left ear). In this posture, vibration conducts from the belt-side cartilage conduction unit  40024   b  via the belt part  40001   b  to the ear cartilage. In a similar manner as described above, the voice of the user himself is collected by the variable-directivity microphone  40023  that has its directivity so switched as to collect sound from the direction of the elbow. 
       FIG. 214(C)  shows a call-conducting posture in which, at the ear on the same side as the hand on which a user is wearing the wrist watch-type handset  40001 , the hand (in the diagram, the forefinger) is put on the ear cartilage (in the diagram, the user puts the forefinger on the tragus to stop the earhole so that the external auditory meatus is closed). In this posture, vibration conducts from the belt-side cartilage conduction unit  40024   b  via the belt part  40001   b  to the wrist and then to the ear cartilage. In a similar manner as described above, the voice of the user himself is collected by the variable-directivity microphone  40023  that has its directivity so switched as to collect sound from the direction of the elbow. 
     The diagrams illustrating call-conducting postures in  FIGS. 213 and 214  are not only displayed on the watch display unit  40005  as described above, but can also be offered to users, along with the wrist watch-type handset  40001  as a commercial product, in a form shown in an instruction manual attached to the wrist watch-type handset  40001  when this is marketed as a commercial product, or in a form distributed via a medium for advertising the wrist watch-type handset  40001 . Accordingly, these distinctive methods of use which are offered along with the wrist watch-type handset  40001  also constitute part of the present invention. 
       FIG. 215  is a system block diagram of the one-hundred thirty-fourth embodiment shown in  FIGS. 212 to 214 .  FIG. 215  has much in common with  FIG. 205  showing the one-hundred twenty-eighth embodiment; therefore, common parts are identified by the same reference numerals, and no overlapping description will be repeated unless necessary. Likewise, such parts as are shown also in  FIG. 212  in connection with the one-hundred thirty-fourth embodiment are identified by the same reference numerals, and no overlapping description will be repeated unless necessary. 
     As shown in  FIG. 215 , the wrist watch-type handset  40001  of the one-hundred thirty-fourth embodiment includes a watch function unit  35039  for the ordinary watch function. An acceleration sensor  40049  detects upward movement of the wrist watch-type handset  40001  from (A) to (B) in  FIG. 213 , and downward movement of the wrist watch-type handset  40001  from (B) to (A) in  FIG. 213 , to automatically switch the camera unit  40017 , the speaker  40013 , and the watch display unit  40005 . 
     A power supply unit  6548  of the wrist watch-type handset  40001  and a power supply unit  1448  of the mobile telephone  35601  are both capable of contactless charging via contactless charging units  6548   a  and  1448   a  respectively. They share information about each other&#39;s charging status by near-field communication to secure coordination between the wrist watch-type handset  40001  and the mobile telephone  35601 . Moreover, a GPS unit  40038  detects the movement of the user who is wearing the wrist watch-type handset  40001 , and every time it does, it checks whether or not the wrist watch-type handset  40001  is left behind without being carried around, in order to secure coordination between the wrist watch-type handset  40001  and the mobile telephone  35601 . Specifically, the GPS unit  40038  checks whether or not the user moves out of the near-field communication range. 
     A drive unit  35036  drives both a display-side cartilage conduction unit  40024   a  and a belt-side cartilage conduction unit  40024   b  to cope with either hearing posture. A configuration is also possible which permits switching such that only one of the display-side cartilage conduction unit  40024   a  and the belt-side cartilage conduction unit  40024   b  vibrates, by finely discriminating postures, or by manual operation. In response to an instruction from a control unit  40039 , a sound processing unit  40040  switches between vibration generation for cartilage conduction by the drive unit  35036  and air-conduction sound generation by the speaker  40013 . In response to an instruction from the control unit  40039  via the sound processing unit  40040 , the variable-directivity microphone  40023  switches its directivity. 
     An incoming-call vibrator  6525  is provided in the belt part  40001   b ; instead, the vibration of the belt-side cartilage conduction unit  40024   b  can be used to obtain a configuration that does not require a separate vibration source. 
       FIG. 216  is a flow chart showing the function of the control unit  40039  of the wrist watch-type handset  40001  of the one-hundred thirty-fourth embodiment. The flow in  FIG. 216  focuses on operation for functions related to cartilage conduction, and in reality the wrist watch-type handset  40001  involves operation of the control unit  40039  other than that shown in the flow in  FIG. 216 , for ordinary wrist watch functions among others. The control unit  40039  can additionally perform any of the functions described in connection with other various handsets, but these functions too are omitted from illustration and description to avoid complication. 
     The flow in  FIG. 216  starts when the main power to the wrist watch-type handset  40001  is turned on. In Step S 862 , a start-up procedure is gone through, checks are made on the functions of different blocks, and ordinary watch display is started on the watch display unit  40005 . Next, in Step S 864 , the methods of use shown in  FIGS. 213 and 214  are displayed in a slide show. On completion of the explanation of the methods of use, then, in Step S 866 , whether or not the GPS unit  40038  has detected user movement is checked. 
     If no user movement has been detected, then, in Step S 868 , it is checked whether or not a scheduled time (e.g., once every five seconds) has arrived at which to secure coordination between the wrist watch-type handset  40001  and the mobile telephone  35601 . If so, the flow advances to Step S 870 . On the other hand, if, in Step S 866 , the GPS unit  40038  has detected user movement, the flow advances directly to Step S 870 . In Step S 870 , whether or not the mobile telephone  35601  has moved out of the near-field communication range is checked, and if it is inside the near-field communication range, the flow advances to Step S 872 . In Step S 872 , near-field communication is conducted with the mobile telephone  35601  to check the power status of the wrist watch-type handset  40001  which is steadily displayed on the watch display unit  40005  and to transmit the result to the mobile telephone  35601 . The transmitted information is displayed on the large-screen display unit  205  of the mobile telephone  35601 . Then, in Step S 874 , information about the power status of the mobile telephone  35601  is received by near-field communication, and the result is displayed on the watch display unit  40005 , the flow then advancing to Step S 876 . On the other hand, if, in Step S 868 , a scheduled time has not yet arrived, the flow advances directly to Step S 876 . 
     In Step S 876 , by near-field communication, it is checked whether or not the mobile telephone  35601  has received an incoming call, or whether or not the other side has responded to a call originating operation on the operation unit  6509  of the wrist watch-type handset  40001 . If either is the case, it means that the mobile telephone  35601  has started to conduct a call with the other side; thus, then, in Step S 878 , the displaying of the other side&#39;s face on the watch display unit  40005 , the shooting of the user&#39;s own face by the camera unit  40017 , and the generation of air-conduction sound by the speaker  40013  are all turned on, and the directivity of the variable-directivity microphone  40023  is set to frontward of the watch display unit  40005 , the flow then advancing to Step S 880 . At this time, the display-side cartilage conduction unit  40024   a  and the belt-side cartilage conduction unit  40024   b  are off. In this way, when a call is started, first, a videophone mode is in effect. If the call is not for a videophone session but for a sound-only session, out of what has been mentioned just above, the displaying of the other side&#39;s face and the turning-on of the camera unit  40017  are omitted. 
     In Step S 880 , it is checked whether or not the acceleration sensor  40049  detects upward movement of the wrist watch-type handset  40001  from (A) to (B) in  FIG. 213 . If such movement is detected, then, in Step S 882 , the displaying of the other side&#39;s face on the watch display unit  40005 , the shooting of the user&#39;s own face by the camera unit  40017 , and the generation of air-conduction sound by the speaker  40013  are all turned off, and instead the display-side cartilage conduction unit  40024   a  and the belt-side cartilage conduction unit  40024   b  are turned on. Moreover, the directivity of the variable-directivity microphone  40023  is set to toward the elbow, and the flow advances to Step S 884 . 
     In Step S 884 , it is checked whether or not the acceleration sensor  40049  detects downward movement of the wrist watch-type handset  40001  from (B) to (A) in  FIG. 213 . If such movement is detected, then, in Step S 878 , the videophone mode is restored. On the other hand, if, in Step S 884 , no downward movement is detected (typically, this state persists so long as a cartilage conduction call continues), then, in Step S 886 , whether or not the call has been disconnected is checked. If the call has not been disconnected, the flow returns to Step S 880 . Thereafter, until the call is detected having been disconnected in Step S 886 , Steps S 878  through S 886  are repeated so that change in posture is coped with by switching between a cartilage conduction call and a videophone call. On the other hand, if, in Step S 886 , the call is detected having been disconnected, the flow advances to Step S 888 . If, in Step S 876 , no call is detected having been started, the flow advances directly to Step S 888 . 
     In Step S 888 , it is checked whether or not a mobile telephone search operation has been performed on the operation unit  6509 . This operation is performed when, for example, a user about to go out cannot find the mobile telephone  35601 . When the operation is performed, then, in Step S 890 , communication is conducted with the mobile telephone  35601  by near-field communication so that an instruction signal is transmitted to the mobile telephone  35601  to make it sound a ringtone (or vibrate the vibrator). The flow then advances to Step S 892 . 
     On the other hand, if, in Step S 870 , the mobile telephone  35601  is detected having moved outside the near-field communication range, then, in Step S 894 , a warning indicating that the mobile telephone  35601  is not being carried around is displayed, and the flow then advances to Step S 892 . By various means as described above, coordination between the wrist watch-type handset  40001  and the mobile telephone  35601  is secured. 
     In Step S 892 , whether or not the main power to the wrist watch-type handset  40001  has been turned off is checked, and if not, then, back in Step S 866 , so long as thereafter the main power is not detected having been turned off, Steps S 866  through Steps S 892  are repeated. On the other hand, if, in Step S 892 , the main power is detected having been turned off, the flow ends. 
     The various features of the present invention in the embodiments described above are not limited to those specific embodiments; they can be implemented in any other embodiment so long as they provide their advantages. Features from different embodiments can be combined into a single embodiment. For example, the various means for coordination between the wrist watch-type handset  40001  and the mobile telephone  35601  shown in  FIGS. 212 to 216  can be applied to a wrist watch-type handset  40001  that does not adopt cartilage conduction. 
     One-Hundred Thirty-Fifth Embodiment 
       FIG. 217  is a system configuration diagram of a one-hundred thirty-fifth embodiment according to one aspect of the present invention. The one-hundred thirty-fifth embodiment is configured as a mobile telephone system comprising a mobile telephone  35601  and an ID name tag-type handset  41001 , and the two can communicate with each other by near-field communication using a radio wave  6585  of a communication system such as Bluetooth™. The mobile telephone system of the one-hundred thirty-fifth embodiment has much in common with the one-hundred thirty-fourth embodiment shown in  FIG. 212 ; therefore, common parts are identified by the same reference numerals as in  FIG. 212 , and no overlapping description will be repeated unless necessary. 
     The ID name tag-type handset  41001  in the one-hundred thirty-fifth embodiment shown in  FIG. 217  functions as a non-contact IC card which is used as an unlocking card for entry into a building, and simultaneously functions as a name tag that has, at the surface, an ID data display unit  41005 , comprising a reflective liquid crystal display, on which a photo  41001   a  and the name  41001   b  of the owner are displayed. It is typically used in a form suspended from the neck via a neck strap  41001   c . As shown in  FIG. 217 , what is displayed is upright as seen from a person present in front of the owner. As will be described later, what is displayed is inverted upside down when the owner himself views it. 
     The ID name tag-type handset  41001  further includes a speaker  41013 , a microphone  41023 , and a camera unit  41017 ; by near-field communication with the mobile telephone  35601 , it functions as a videophone handset for the mobile telephone  35601 . In that case, the face of the other side is displayed inverted upside down compared with in the case shown in  FIG. 217 . Use as a videophone terminal will be described in detail later. 
     The ID name tag-type handset  41001  further includes, in a corner part, a cartilage conduction unit  41024 . With the cartilage conduction unit  41024  put in contact with the tragus, the ID name tag-type handset  41001  functions as a handset that allows calls by cartilage conduction as in other embodiments. For talk transmission, the variable-directivity microphone  41023 , which is used in videophone calls, is shared. In the one-hundred thirty-fifth embodiment, the cartilage conduction unit  41024  is arranged in a bottom part of the ID name tag-type handset  41001  when this is suspended from the neck. This makes it easy to bring it up to put the cartilage conduction unit  41024  on the tragus, and when it is put on the tragus, it does not interfere with the neck strap  41001   c.    
     The ID name tag-type handset  41001  further includes an incoming-call vibrator  6525 , which, by near-field communication using a radio wave  6585  with the mobile telephone  35601 , receives an incoming-call signal and vibrates. The neck strap  41001   c  is formed of a material with a good vibration-conducting property, and is connected to the incoming-call vibrator  6525 . With this configuration, the vibration of the incoming-call vibrator  6525  conducts via the neck strap  41001   c  to the skin at the back of the neck, and thus a user can clearly feel an incoming call. The neck strap  41001   c  is tense under the weight of the ID name tag-type handset  41001 , and thus it effectively conducts the vibration of the incoming-call vibrator  6525  to the neck. 
       FIG. 218  is an enlarged view of the ID name tag-type handset  41001  shown in  FIG. 217 ; such parts as are shown also in  FIG. 217  are identified by the same reference numerals, and no overlapping description will be repeated unless necessary. Like  FIG. 217 ,  FIG. 218(A)  shows the ID name tag-type handset  41001  in a state suspended from the neck, where what is displayed is all upright as seen from a person present in front. Though omitted from illustration in  FIG. 217 , an operation unit  6509  permits the ID name tag-type handset  41001  to be turned on for power, switched and set in different ways, fed with input, and otherwise controlled. 
     In addition to what has been described in reference to  FIG. 217 , the ID data display unit  41005  has a charge status indicator  41001   d  for the battery of the ID name tag-type handset  41001 . Moreover, the ID data display unit  41005  has a charge status indicator  41001   e  for the battery of the mobile telephone  35601  and an incoming-call mode indicator  41001   f  which indicates whether the mobile telephone  35601  is set to a ringtone mode or a vibration mode with respect to an incoming call.  FIG. 218  shows a state where the ringtone mode is in effect. When the mobile telephone  35601  is set to the vibration mode, the incoming-call mode indicator  41001   f  changes to a heart-like icon as will be described later. The data to be displayed about the mobile telephone  35601  is transmitted from the mobile telephone  35601  by near-field communication. By showing various indications so that these are visible to a person present in front in this way, when the person notices the battery running out or the vibration mode not being in effect, he can warn the user. 
       FIG. 218(B)  shows a state in which a user has brought up the ID name tag-type handset  41001  while flipping it toward himself so that the user himself can view it. At this time, the neck strap  41001   c  is brought down. In  FIG. 218(B) , it appears as if the components including the cartilage conduction unit  41024  are all rotated by 180 degrees parallel to the plane of the diagram from what is shown in  FIG. 218(A) , this is not the case. Whereas  FIG. 218(A)  shows a state as seen from a person present in front,  FIG. 218(B)  shows a state as seen from the owner. It is thus not that the ID name tag-type handset  41001  itself can be flipped by 180 degrees parallel to the ID data display unit  41005  when switched from the state in  FIG. 218(A)  to the state in  FIG. 218(B) . 
     For the reason stated above, if, for the sake of discussion, the owner brings up the ID name tag-type handset  41001  while flipping it toward himself with the display state in  FIG. 218(A)  maintained, what is displayed, including the owner&#39;s photo  41001   a  and name  41001   b , is all displayed inverted. To avoid that, in the state in  FIG. 208(B) , each segment of what is displayed on the ID data display unit  41005  is rotated by 180 degrees and rearranged by image processing. As a result, even when the owner has brought up the ID name tag-type handset  41001  while flipping it toward himself so that the owner himself can view it, he can view what is displayed, including the owner&#39;s photo  41001   a  and name  41001   b , upright, and can, while viewing the display, operate the operation unit  6509  to change settings or enter data. 
       FIG. 219  shows the ID name tag-type handset  41001  in a state where the owner himself is viewing it in a similar manner as in  FIG. 218(B) . Such parts as are shown also in  FIG. 218(B)  are identified by the same reference numerals, and no overlapping description will be repeated unless necessary.  FIG. 219(A)  shows a state where a mail message  41001   g  is being displayed. In  FIG. 219(A) , the mobile telephone  35601  has been set to the vibration mode, with the result that the incoming-call mode indicator  41001   f  has changed to a heart-like icon.  FIG. 219(B)  shows a state where the other side&#39;s face is being displayed in the videophone mode. 
       FIG. 220  is a system block diagram of the one-hundred thirty-fourth embodiment shown in  FIGS. 212 to 214 .  FIG. 220  has much in common with  FIG. 215 , which is a system block diagram of the one-hundred thirty-fourth embodiment; therefore, common parts are identified by the same reference numerals as in  FIG. 215 , and no overlapping description will be repeated unless necessary. Likewise, such parts as are also shown in  FIGS. 217 to 219  in connection with the one-hundred thirty-fifth embodiment are identified by the same reference numerals, and no overlapping description will be repeated unless necessary. 
     In  FIG. 220 , by communication via a card antenna  41001   j , a non-contact IC card function unit  41001   i  makes the ID name tag-type handset  41001  function as a non-contact IC card. Thus, with a touch on a building entry authorization unit with the ID name tag-type handset  41001 , the owner can unlock a lock or is otherwise authorized to enter a building. Also, via a near-field communication unit  6546 , the non-contact IC card function unit  41001   i  can cooperate with the payment clearance function of the mobile telephone  35601  to make the ID name tag-type handset  41001  function as a payment clearance card. With a touch on a payment clearance unit with the ID name tag-type handset  41001 , the owner can clear a payment or the like via the mobile telephone  35601 . 
     In  FIG. 220 , a neck strap connection part  41001   k  is a part to which the neck strap  41001   c  for conducting incoming-call vibration to the neck is connected and to which the vibration of the incoming-call vibrator  6525  is conducted. Thus, the vibration conducted from the incoming-call vibrator  6525  to the neck strap connection part  41001   k  is then conducted to the neck strap  41001   c , permitting the owner to feel an incoming call at the back of the neck. 
     Furthermore, in  FIG. 220 , an acceleration sensor  41049  detects gravitational acceleration; it discriminates whether the non-contact IC card function unit  41001   i  is in the position in  FIG. 218(A)  or in the position in  FIG. 218(B)  to invert what is displayed upside down and adjust its layout. The acceleration sensor  41049  also detects whether the non-contact IC card function unit  41001   i  is in the position in  FIG. 218(A)  and is being used as a videophone or is brought farther up to so that the cartilage conduction unit  41024  is put in contact with the tragus. Based on the output of the acceleration sensor  41049 , the sound processing unit  41040  switches between generating air-conduction sound from the speaker  41013  based on an audio signal or vibrating the cartilage conduction unit  41024  via the drive unit  35036 . The control unit  41039  controls the entire ID name tag-type handset  41001  including the above-described functions according to programs stored in the storage unit  6537 . 
       FIG. 221  is a flow chart showing the function of the control unit  41039  of the ID name tag-type handset  41001  in the one-hundred thirty-fifth embodiment. The flow in  FIG. 221  focuses on operation for functions related to cartilage conduction, and in reality the ID name tag-type handset  41001  involves operation of the control unit  41039  other than that shown in the flow in  FIG. 221 , for ordinary ID name tag functions among others. The control unit  41039  can additionally perform any of the functions described in connection with other various embodiments, but these functions too are omitted from illustration and description to avoid complication. 
     The flow in  FIG. 221  starts when the main power to the ID name tag-type handset  41001  is turned on. In Step S 902 , a start-up procedure is gone through, checks are made on the functions of different blocks, and display of ID data (the photo  41001   a  and the name  41001   b ) is started on the ID data display unit  41005 . Next, in Step S 904 , the top/bottom direction of each item of what is being displayed, such as the ID data, is set to that in the suspended state in  FIG. 218(A) . Then, in Step S 906 , the charge status indicator  41001   d  for the battery of the ID name tag-type handset  41001 , the charge status indicator  41001   e  for the battery of the mobile telephone  35601 , and the incoming-call mode indicator  41001   f  are displayed so as to be visible from a person present in front. The flow then advances to Step S 908 . 
     In Step S 908 , it is checked whether or not an incoming-call signal has been transmitted from the mobile telephone  35601  by near-field communication, and if so, then, in Step S 910 , the incoming-call vibrator  6525  is turned on. This causes vibration to conduct via the neck strap connection part  41001   k  to the neck strap  41001   c , and the owner can feel the incoming call at the back of the neck. Next, in Step S 912 , it is checked whether or not an operation responding to the incoming call has been done on the operation unit  6509 , or whether or not the other side has stopped originating the call and the incoming-call signal from the mobile telephone  35601  has ceased to be transmitted, is checked. If neither is the case, then, back in Step S 910 , so long as, in Step S 912 , neither state is thereafter detected, Steps S 910  and S 912  are repeated. On the other hand, if, in Step S 912 , either state is detected, then, in Step S 914 , the incoming-call vibrator  6525  is turned off, and the flow advances to Step S 916 . If, in Step S 908 , no incoming-call signal is detected, the flow advances directly to Step S 916 . 
     In Step S 916 , it is checked whether or not the acceleration sensor  40049  has detected a change in the state of the ID name tag-type handset  41001  from the state in  FIG. 218(A)  to the brought-up position in  FIG. 2218(B) . If the brought-up position is detected, then, in Step S 918 , the top/bottom direction of what is being displayed is changed from that in  FIG. 218(A)  to that for the brought-up state in  FIG. 218(B) , and the ID name tag-type handset  41001  is set to an ordinary call mode using the microphone  41023  and the speaker  41013 , the flow then advancing to Step S 920 . In the ordinary call mode, the cartilage conduction unit  41024  is off. On the other hand, if, in Step S 916 , the brought-up position is not detected, the flow advances directly to Step S 920 . 
     In Step S 920 , based on the output of the acceleration sensor  40049 , it is checked whether or not the ID name tag-type handset  41001  has been brought farther up from the state in  FIG. 218(B)  into a cartilage conduction position in which the cartilage conduction unit  41024  is put in contact with the tragus. If the cartilage conduction position is detected, then, in Step S 922 , the cartilage conduction unit  41024  is turned on and the speaker  41013  is turned off, the flow then advancing to Step S 924 . Moreover, in Step S 922 , if the backlight (not shown) for the reflective liquid crystal display provided in the ID data display unit  41005  is on, it is turned off. On the other hand, if, in Step S 920 , the cartilage conduction position is not detected, the flow advances directly to Step S 924 . 
     In Step S 924 , it is checked whether or not the acceleration sensor  40049  has detected a return to the suspended position in  FIG. 218(A) . If the suspended position is detected, then, in Step S 926 , the top/bottom direction of what is being displayed is changed from that in  FIG. 218(B)  to that in the suspended position in  FIG. 218(A) , and the ID name tag-type handset  41001  is set to the ordinary call mode using the microphone  41023  and the speaker  41013 , the flow then advancing to Step S 928 . On the other hand, if, in Step S 924 , the suspended state is not detected, the flow advances directly to Step S 928 . 
     In Step S 928 , it is checked whether or not a touch with the ID name tag-type handset  41001  has been made on a building entry authorization unit or on a payment clearance unit. If so, then, in Step S 930 , the corresponding process is performed according to the above-described functions of the non-contact IC card function unit  41001   i , and the flow advances to Step S 932 . On the other hand, if, in Step S 928 , no touch is detected on a building entry authorization unit or on a payment clearance unit, the flow advances directly to Step S 932 . 
     In Step S 932 , whether or not the main power to the ID name tag-type handset  41001  has been turned off is checked, and if not, back in Step S 908 , so long as the main power is thereafter detected having been turned off, Steps S 908  through S 932  are repeated. In this way, although having the functions of a handset and a non-contact IC card, the ID name tag-type handset  41001  ordinarily functions as an ID name tag suspended from the neck, continuing to display the photo  41001   a  and the name  41001   b  on the ID data display unit  41005 . 
     The various features of the present invention in the embodiments described above are not limited to those specific embodiments; they can be implemented in any other embodiment so long as they provide their advantages. Features from different embodiments can be combined into a single embodiment. For example, although the embodiment shown in  FIGS. 217 to 221  is configured as a handset that is coordinated with a mobile telephone, its features can be applied to a name tag, or a non-contact IC card, with no handset capabilities. 
     One-Hundred Thirty-Sixth Embodiment 
       FIG. 222  comprises a perspective view and sectional views of a one-hundred thirty-sixth embodiment according to one aspect of the present invention, which is configured as a mobile telephone  42001 . The one-hundred thirty-sixth embodiment has much in common with the one-hundred seventh embodiment in  FIG. 178  (described with complementary reference to the eighty-eighth embodiment in  FIG. 136 ); therefore, common parts are identified by the same reference numerals, and no overlapping description will be repeated unless necessary. As in the one-hundred seventh embodiment,  FIG. 222(A)  is a front perspective view of the one-hundred thirty-sixth embodiment. The mobile telephone  42001  has a casing that is composed of a metal frame held between a front plate  8201   a  made of plastic or the like and a back plate  8201   b  formed of plastic. The metal frame divides into a top frame  8227 , a right frame  8201   c , a bottom frame  8201   d , and a left frame  8201   e  (not shown in  FIG. 222(A) ), and insulating members  42001   f  are inserted between every two adjacent ones of them. In this configuration, the front plate  8201   a , the back plate  8201   b , and the top frame  8227  constitute a casing top face portion. 
     The outer sides of opposite corner parts of the top frame  8227  are coated by, by bonding thereto of, a right-ear cartilage conduction unit  42024  and a left-ear cartilage conduction unit  42026 , and the top face of the top frame  8227  is coated by, by bonding thereto of, a linking unit  42027 , which links together the right-ear cartilage conduction unit  42024  and the left-ear cartilage conduction unit  42026 . The right-ear cartilage conduction unit  42024 , the left-ear cartilage conduction unit  42026 , and the linking unit  42027  are made of an elastic member having an acoustic impedance close to that of the ear cartilage. The front plate  8201   a , the back plate  8201   b , and the top frame  8227  have a different acoustic impedance from the right-ear cartilage conduction unit  42024 , the left-ear cartilage conduction unit  42026  and the linking unit  42027 , so that it is difficult for the vibration of the latter three to conduct to the former three. 
       FIG. 222(B)  is a sectional view along line B 1 -B 1  in  FIG. 222(A) ; common parts are identified by the same reference numerals, and no overlapping description will be repeated unless necessary. As will be clear from  FIG. 222(B) , on the bottom of the linking unit  42027 , an extension part  42027   c  is provided which penetrates through an opening in the top frame  8227  into the mobile telephone  42001 . One, upper, end of a piezoelectric bimorph element  13025  is inserted into the extension part  42027   c  so as to be supported at one end (in a cantilever fashion). This permits the other, lower, end of the piezoelectric bimorph element  13025  to vibrate freely, and a reaction is transmitted to the extension part  42027   c . The extension part  42027   c  is molded integrally with, with the same elastic member as, the linking unit  42027 , and thus its vibration is efficiently transmitted via the linking unit  42027  to each of the right-ear cartilage conduction unit  42024  and the left-ear cartilage conduction unit  42026 . The vibration direction is perpendicular to the front plate  8201   a  (perpendicular to the plane of  FIG. 222 ). 
     With the configuration described above, by putting the right-ear cartilage conduction unit  42024  or the left-ear cartilage conduction unit  42026  in contact with the ear cartilage, it is possible to obtain satisfactory cartilage conduction. As described above, the piezoelectric bimorph element  13025  is supported only by the extension part  42027   c , which has an acoustic impedance close to that of the ear cartilage, and vibration is transmitted via the linking unit  42027 , which is molded integrally with the extension part  42027   c , to the right-ear cartilage conduction unit  42024  or the left-ear cartilage conduction unit  42026  and then to the ear cartilage. This achieves efficient cartilage conduction. On the other hand, the piezoelectric bimorph element  13025  does not make contact with the top frame  8227 , the front plate  8201   a , or the back plate  8201   b , and thus vibration does not conducts directly to these. Moreover, the top frame  8227 , the front plate  8201   a , and the back plate  8201   b  have a different acoustic impedance from the elastic member forming the right-ear cartilage conduction unit  42024  and the left-ear cartilage conduction unit  42026 , and thus the vibration of the elastic member is shut out. With these features, the generation of air-conduction sound by the vibration of the front plate  8201   a  and the back plate  8201   b  is suppressed. Furthermore, the linking unit  42027 , the right-ear cartilage conduction unit  42024 , and the left-ear cartilage conduction unit  42026  are bonded to the top frame  8227 , and thus vibration in the direction perpendicular to their surfaces is suppressed. Thus, also the generation of air-conduction sound from the linking unit  42027 , the right-ear cartilage conduction unit  42024 , and the left-ear cartilage conduction unit  42026  themselves is suppressed. 
     Moreover, the outer sides of the opposite corner parts of the top frame  8227  are coated by the elastic members forming the right-ear cartilage conduction unit  42024  and the left-ear cartilage conduction unit  42026  respectively, and thus those two corner parts are protected from impact when the mobile telephone  42001  is dropped. Furthermore, the piezoelectric bimorph element  13025  is supported only by an elastic member, which thus serves as a shock-absorbing member and protects the piezoelectric bimorph element  13025  from destruction by impact such as when the mobile telephone  42001  is dropped. 
     In  FIG. 222(B) , which is a sectional view along line B 1 -B 1  in  FIG. 222(A) , it appears as if the linking unit  42027  is divided by an external earphone jack  8246  and a power switch  8209 ; in  FIG. 222(C) , which is a top view of  FIG. 222(A) , it is seen that the right-ear cartilage conduction unit  42024 , the left-ear cartilage conduction unit  42026 , and the linking unit  42027  are formed continuously and integrally out of the elastic member. In  FIG. 222(C) , the extension part  42027   c  and the piezoelectric bimorph element  13025  inserted into it, which are both housed inside, are indicated by broken lines. 
       FIG. 222(D) , which is a sectional view along line B 2 -B 2  shown in  FIGS. 222(A) to 222(C) , shows that the extension part  42027   c  is integral with the linking unit  42027 , and that the free end of the piezoelectric bimorph element  13025  inserted in it vibrates in the direction perpendicular to the front plate  8201   a  as indicated by arrows  13025   a . Moreover, in  FIG. 222(D) , it is seen that the free end of the piezoelectric bimorph element  13025  vibrates without making contact with other than the extension part  42027   c , and that a reaction of the vibration conducts via the extension part  42027   c  only to the linking unit  42027 . 
     One-Hundred Thirty-Seventh Embodiment 
       FIG. 223  comprises sectional views of a one-hundred thirty-seventh embodiment according to one aspect of the present invention and a modified example thereof, which is configured as a mobile telephone  43001  and a mobile telephone  44001  respectively. The one-hundred thirty-seventh embodiment and its modified example have much in common with one-hundred thirty-sixth embodiment in  FIG. 222 ; therefore, common parts are identified by the same reference numerals, and no overlapping description will be repeated unless necessary. In exterior appearance, the one-hundred thirty-seventh embodiment is no different from the one-hundred thirty-sixth embodiment; therefore, in this aspect,  FIG. 222(A)  is to be referred to for a complement, and  FIG. 223  comprises no perspective view. The one-hundred thirty-seventh embodiment in  FIG. 223  differs from the one-hundred thirty-sixth embodiment in  FIG. 222  in that, whereas in the one-hundred thirty-sixth embodiment the piezoelectric bimorph element  13025  is arranged vertically, in the one-hundred thirty-seventh embodiment or its modified example, a piezoelectric bimorph element  43025  or  44025 , respectively, is arranged horizontally. 
       FIG. 223(A)  corresponds to a sectional view of the one-hundred thirty-seventh embodiment along line B 1 -B 1  in  FIG. 222(A) . As will be clear from  FIG. 223(A) , also in the one-hundred thirty-seventh embodiment, under a linking unit  43027  which links together a right-ear cartilage conduction unit  43024  and a left-ear cartilage conduction unit  43026 , there is provided an extension part  43027   c  which penetrates through a hole provided in a top frame  8227  into the mobile telephone  43001 . However, the piezoelectric bimorph element  43025  is arranged horizontally, and has one, right, end thereof inserted in the extension part  43027   c  so that the piezoelectric bimorph element  43025  is supported at one end. Thus, the other end, i.e., the left end in the drawing, of the piezoelectric bimorph element  43025  vibrates freely, and a reaction is conducted via the extension part  43027   c  and then via the linking unit  43027  to each of the right-ear cartilage conduction unit  43024  and the left-ear cartilage conduction unit  43026 . As in the one-hundred thirty-sixth embodiment, the vibration direction is perpendicular to the front plate  8201   a  (perpendicular to the plane of  FIG. 223(A) . 
     In  FIG. 223(B) , which corresponds to a top view of  FIG. 222(A)  (showing the one-hundred thirty-sixth embodiment referred to for a complement), it is seen that, in the one-hundred thirty-seventh embodiment, as in the one-hundred thirty-sixth embodiment, the right-ear cartilage conduction unit  43024 , the left-ear cartilage conduction unit  43026 , and the linking unit  43027  are molded continuously and integrally out of an elastic member. Moreover, as in  FIG. 222(C) , in  FIG. 223(B) , the extension part  43027   c  and the piezoelectric bimorph element  43025  inserted in it horizontally, which are housed inside, are indicated by broken lines. In  FIG. 223(C) , which is a sectional view along line B 2 -B 2  shown in  FIGS. 223(A) and 223(B) , it is seen that, as in the one-hundred thirty-sixth embodiment, in the one-hundred thirty-seventh embodiment, the extension part  43027   c  is integral with the linking unit  43027 . 
     As in the one-hundred thirty-sixth embodiment, also in the one-hundred thirty-seventh embodiment, the piezoelectric bimorph element  43025  is supported only by the extension part  43027   c , and vibration is conducted via the linking unit  43027  formed integrally with it to the right-ear cartilage conduction unit  43024  or the left-ear cartilage conduction unit  43026  and then to the ear cartilage. This achieves efficient cartilage conduction. Moreover, vibration does not conduct from the piezoelectric bimorph element  43025  directly to the top frame  8227 , the front plate  8201   a , and the back plate  8201   b . In addition, owing to a difference in acoustic impedance, the vibration of the elastic member is shut out from the top frame  8227 , the front plate  8201   a , and the back plate  8201   b , and this suppresses generation of air-conduction sound by the vibration of the front plate  8201   a  and the back plate  8201   b . Moreover, owing to the bonding to the top frame  8227 , generation of air-conduction sound from the linking unit  43027 , the right-ear cartilage conduction unit  43024 , and the left-ear cartilage conduction unit  43026  themselves is suppressed. Owing to the coating by the elastic member constituting the right-ear cartilage conduction unit  43024  and the left-ear cartilage conduction unit  43026 , the two corner parts are protected from impact when the mobile telephone  43001  is dropped, and owing to the shock absorbing property of the elastic member, the piezoelectric bimorph element  43025  is prevented from destruction as when the mobile telephone  43001  is dropped. 
       FIGS. 223(D) to 223(F)  show a modified example of the one-hundred thirty-seventh embodiment.  FIG. 223(D)  corresponds to a sectional view along line B 1 -B 1  in  FIG. 222(A)  (showing the one-hundred thirty-sixth embodiment referred to for a complement). As shown in  FIG. 223(D) , in the modified example, at equal distances from the mid point between the right-ear cartilage conduction unit  44024  and the left-ear cartilage conduction unit  44026 , two extension parts  44027   e  and  44027   f  are provided which extend from the linking unit  44027  through two openings formed in the top frame  8227  into the mobile telephone  44001 . The piezoelectric bimorph element  44025  is arranged horizontally, and is here supported at both ends by being inserted in the two extension parts  44027   e  and  44027   f  from inward, instead of being supported at one end as in the one-hundred thirty-seventh embodiment. This type of support can be achieved, for example, by inserting opposite ends of the piezoelectric bimorph element  44025  into the extension parts  44027   e  and  44027   f  while the interval between these is being widened by exploiting their elasticity. With the piezoelectric bimorph element  44025  supported at opposite ends in this way, a middle part thereof vibrates freely, and a reaction is conducted via the extension parts  44027   e  and  44027   f  and then via the linking unit  44027  to each of the right-ear cartilage conduction unit  44024  and the left-ear cartilage conduction unit  44026 . As in the one-hundred thirty-seventh embodiment, the vibration direction is perpendicular to the front plate  8201   a  (perpendicular to the plane of  FIG. 223(D) ). 
     In  FIG. 223(E) , which corresponds to a top view of  FIG. 222(A)  (showing the one-hundred thirty-sixth embodiment referred to for a complement), it is seen that, also in the modified example of the one-hundred thirty-seventh embodiment, as in the one-hundred thirty-seventh embodiment in  FIG. 223(A) , the right-ear cartilage conduction unit  44024 , the left-ear cartilage conduction unit  44026 , and the linking unit  44027  are molded continuously and integrally out of an elastic member. Moreover, as in  FIG. 223(B) , also in  FIG. 223(E) , the two extension parts  44027   e  and  44027   f  and the piezoelectric bimorph element  44025  supported horizontally by being held between them, which are all housed inside, are indicated by broken lines. In  FIG. 223(F) , which is a sectional view along line B 2 -B 2  shown in  FIGS. 223(D) and 223(E) , it is seen that, as in the one-hundred thirty-seventh embodiment, also in its modified example, the extension part  44027   f  is integral with the linking unit  44027 . 
     Also in the modified example of the one-hundred thirty-seventh embodiment, the piezoelectric bimorph element  44025  is supported only by the two extension parts  44027   e  and  44027   f , and vibration is conducted via the linking unit  44027  formed integrally with them to the right-ear cartilage conduction unit  44024  or the left-ear cartilage conduction unit  44026  and then to the ear cartilage. Thus, efficient cartilage conduction is achieved likewise. Also achieved likewise are suppression of generation of air-conduction sound by the vibration of the front plate  8201   a  and the back plate  8201   b , and suppression of generation of air-conduction sound from the linking unit  44027 , the right-ear cartilage conduction unit  44024 , and the left-ear cartilage conduction unit  44026  themselves. Further achieved likewise are, in case the mobile telephone  44001  is dropped, protection of the two corner parts by the elastic member, and protection of the piezoelectric bimorph element  44025  itself by the elastic member&#39;s shock-absorbing property. 
     One-Hundred Thirty-Eighth Embodiment 
       FIG. 224  comprises a perspective view and sectional views of a one-hundred thirty-eighth embodiment according to one aspect of the present invention, which is configured as a mobile telephone  45001 . The one-hundred thirty-eighth embodiment has much in common with the one-hundred thirty-sixth embodiment in  FIG. 222 ; therefore, common parts are identified by the same reference numerals, and no overlapping description will be repeated unless necessary. A first difference of the one-hundred thirty-eighth embodiment in  FIG. 224  from the one-hundred thirty-sixth embodiment in  FIG. 222  is that, whereas in the one-hundred thirty-sixth embodiment, the piezoelectric bimorph element  13025  is supported vertically at one end, in the one-hundred thirty-eighth embodiment, the piezoelectric bimorph element  45025  is entirely bonded horizontally. A second difference is that a cartilage conduction unit is arranged so as to cover opposite corner parts of the top face of the mobile telephone  45001 . A specific description follows. 
     Like  FIG. 222(A)  showing the one-hundred thirty-sixth embodiment,  FIG. 224(A)  is a front perspective view of the one-hundred thirty-eighth embodiment. The following description focuses on features that are different from the one-hundred thirty-sixth embodiment. The top face, front and rear faces, and side faces of opposite top corner parts of the mobile telephone  45001  (parts of the front plate  8201   a , back plate  8201   b , and top frame  8227  corresponding to those corners) are entirely covered by a right-ear cartilage conduction unit  45024  and a left-ear cartilage conduction unit  45026  respectively. The so shaped right-ear and left-ear cartilage conduction units  45024  and  45026  respectively coat the opposite top corner parts of the mobile telephone  45001  by being bonded to them. The top face of the top frame  8227  is coated by a linking unit  45027  which links together the right-ear and left-ear cartilage conduction units  45024  and  45026  as described above. As in the one-hundred thirty-sixth embodiment, also in the one-hundred thirty-eighth embodiment, the right-ear cartilage conduction unit  45024 , the left-ear cartilage conduction unit  45026 , and the linking unit  45027  are molded integrally out of an elastic member having an acoustic impedance similar to that of the ear cartilage. 
       FIG. 224(B)  corresponds to a sectional view along line B 1 -B 1  in  FIG. 224(A) . As will be clear from  FIG. 224(B) , also in the one-hundred thirty-eighth embodiment, on the bottom of the linking unit  45027  which links together the right-ear cartilage conduction unit  45024  and the left-ear cartilage conduction unit  45026 , there is provided an extension part  45027   c  which penetrates through a hole provided in the top frame  8227  into the mobile telephone  45001 . The piezoelectric bimorph element  45025  is supported horizontally by being entirely bonded to the front face of the extension part  45027   c . Thus, as the entire piezoelectric bimorph element  45025  vibrates, the extension part  45027   c  vibrates, and this vibration is conducted via the linking unit  45027  to each of the right-ear cartilage conduction unit  45024  and the left-ear cartilage conduction unit  45026 . As in the one-hundred thirty-sixth embodiment, the vibration direction is perpendicular to the front plate  8201   a  (perpendicular to the plane of  FIG. 224(B) ). 
       FIG. 224(C)  is a top view of  FIG. 224(A) , and there it is seen that, as in the one-hundred thirty-sixth embodiment, the right-ear cartilage conduction unit  45024 , the left-ear cartilage conduction unit  45026 , and the linking unit  45027  are molded continuously and integrally out of an elastic member. Moreover, as in  FIG. 222(C) , also in  FIG. 224(C) , the extension part  45027   c  and the piezoelectric bimorph element  45025  entirely affixed horizontally to it, which are housed inside, are indicated by broken lines. In  FIG. 224(D) , which is a sectional view along line B 2 -B 2  shown in  FIGS. 224(A) to 224(C) , it is seen that, as in the one-hundred thirty-sixth embodiment, also in the one-hundred thirty-eighth embodiment, the extension part  45027   c  is integral with the linking unit  45027 . Already in the one-hundred thirty-sixth and one-hundred thirty-seventh embodiments, the piezoelectric bimorph element is arranged near the back plate  8201   b  to achieve a configuration where a space is secured near the front plate  8201   a  in a top part of the mobile telephone  45001  where a large number of members are arranged. In particular in the one-hundred thirty-eighth embodiment, the piezoelectric bimorph element  45025  is entirely affixed horizontally to the extension part  45027   c , and thus, as will be clear from  FIG. 224(D) , it is possible to more efficiently secure a space near the front plate  8201   a  in a top part of the mobile telephone  45001 . 
     Also in the one-hundred thirty-eighth embodiment, the piezoelectric bimorph element  45025  is supported only by the extension part  45027   c , and vibration is transmitted via the linking unit  45027  molded integrally with it to the right-ear cartilage conduction unit  45024  or the left-ear cartilage conduction unit  45026  and then to the ear cartilage. Thus, efficient cartilage conduction is achieved likewise. Also achieved likewise are suppression of generation of air-conduction sound by the vibration of the front plate  8201   a  and the back plate  8201   b , and suppression of generation of air-conduction sound from the linking unit  45027 , the right-ear cartilage conduction unit  45024 , and the left-ear cartilage conduction unit  45026  themselves. Further achieved likewise are, in case the mobile telephone  45001  is dropped, protection of the two corner parts by the elastic member, and protection of the piezoelectric bimorph element  45025  itself by the elastic member&#39;s shock-absorbing property. 
     Moreover, in the one-hundred thirty-eighth embodiment, as will be clear from  FIG. 224(A) , the right-ear cartilage conduction unit  45024  and the left-ear cartilage conduction unit  45026  are arranged so as to cover corner parts of the top face of the mobile telephone  45001 . This results in an increased area of contact with the ear cartilage, and helps achieve more efficient cartilage conduction. The structure is thus one of those structures which are suitable to protect corner parts. 
     One-Hundred Thirty-Ninth Embodiment 
       FIG. 225  comprises a perspective view and sectional views of a one-hundred thirty-ninth embodiment according to one aspect of the present invention, which is configured as a mobile telephone  46001 . The one-hundred thirty-ninth embodiment too has much in common with the one-hundred thirty-sixth embodiment in  FIG. 222 ; therefore, common parts are identified by the same reference numerals, and no overlapping description will be repeated unless necessary. The one-hundred thirty-ninth embodiment in  FIG. 225  differs from the one-hundred thirty-sixth embodiment in  FIG. 222  in that, whereas in the one-hundred thirty-sixth embodiment, the piezoelectric bimorph element  13025  is supported vertically at one end, in the one-hundred thirty-ninth embodiment, as in the one-hundred thirty-eighth embodiment, a piezoelectric bimorph element  46025  is entirely bonded horizontally. However, in the one-hundred thirty-ninth embodiment, unlike in the one-hundred thirty-eighth embodiment, the vibration direction of the piezoelectric bimorph element  46025  is perpendicular to the top frame  8227  (the up/down direction in the mobile telephone  46001 ). 
     Like  FIG. 222(A)  showing the one-hundred thirty-sixth embodiment,  FIG. 225(A)  is a front perspective view of the one-hundred thirty-ninth embodiment. There is no difference in exterior appearance, and therefore no overlapping description will be repeated.  FIG. 225(B)  corresponds to a sectional view along line B 1 -B 1  in  FIG. 225(A) . As will be clear from  FIG. 225(B) , in the one-hundred thirty-ninth embodiment, part of a bottom part of a linking unit  46027  that links together a right-ear cartilage conduction unit  46024  and a left-ear cartilage conduction unit  46026  constitutes an exposed part  46027   c  which is exposed through an opening formed in the top frame  8227 . The piezoelectric bimorph element  46025  is supported by being entirely bonded horizontally to the bottom face of the exposed part  46027   c . Its vibration direction is perpendicular to the top frame  8227  (the up/down direction in the mobile telephone  46001 ) as indicated by arrows  46025   a . Thus, as in the one-hundred thirty-eighth embodiment, also in the one-hundred thirty-ninth embodiment, as the entire piezoelectric bimorph element  46025  vibrates, the exposed part  46027   c  vibrates, and this vibration is conducted via the linking unit  46027  to each of the right-ear cartilage conduction unit  46024  and the left-ear cartilage conduction unit  46026 . 
       FIG. 225(C)  is a top view of  FIG. 225(A) , and there it is seen that, as in the one-hundred thirty-sixth embodiment, the right-ear cartilage conduction unit  46024 , the left-ear cartilage conduction unit  46026 , and the linking unit  46027  are molded continuously and integrally out of an elastic member. Moreover, the exposed part  46027   c  and the piezoelectric bimorph element  46025  entirely affixed horizontally to it from behind, which are housed inside, are indicated by broken lines. Also in  FIG. 225(D) , which is a sectional view along line B 2 -B 2  shown in  FIGS. 225(A) to 225(C) , it is seen how the exposed part  46027   c  is exposed through the opening provided in the top frame  8227  and how the piezoelectric bimorph element  46025  is affixed to it so as to point upward. Moreover, as will be understood from  FIGS. 225(B) and 225(D) , in the one-hundred thirty-ninth embodiment, the vibration direction of the piezoelectric bimorph element  46025  is, as indicated by arrows  46025   a , perpendicular to the top frame  8227  (the direction upward from the mobile telephone  46001  with respect to the ear cartilage). This is one of those arrangements which require the least space inside the mobile telephone  46001 , and is suitable to introduce a cartilage conduction structure in a top part of the mobile telephone  46001  where a large number of members are arranged. 
     Also in the one-hundred thirty-ninth embodiment, the piezoelectric bimorph element  46025  is affixed to the exposed part  46027   c  so as to be supported only by the linking unit  46027 , and vibration is conducted via the right-ear cartilage conduction unit  46024  or the left-ear cartilage conduction unit  46026  integrally molded to it to the ear cartilage. This achieves efficient cartilage conduction. Moreover, also in the one-hundred thirty-ninth embodiment, as in the embodiments described previously, generation of air-conduction sound resulting from vibration of the front plate  8201   a  or the back plate  8201   b , and generation of air-conduction sound frim the linking unit  46027  and from the right-ear cartilage conduction unit  46024  and the left-ear cartilage conduction unit  46026  themselves, are both suppressed. Also obtained likewise are the benefits of, in case the mobile telephone  46001  is dropped, protection the two corner parts being protected by the elastic member, and the piezoelectric bimorph element  46025  itself being protected by the elastic member&#39;s shock-absorbing property. 
     One-Hundred Fortieth Embodiment 
       FIG. 226  comprises a perspective view and sectional views of a one-hundred fortieth embodiment according to one aspect of the present invention, which is configured as a mobile telephone  47001 . The one-hundred fortieth embodiment too has much in common with the one-hundred thirty-sixth embodiment in  FIG. 222 ; therefore, common parts are identified by the same reference numerals, and no overlapping description will be repeated unless necessary. A first difference of the one-hundred fortieth embodiment in  FIG. 226  from the one-hundred thirty-sixth embodiment in  FIG. 222  is that, whereas in the one-hundred thirty-sixth embodiment, the piezoelectric bimorph element  13025  is supported vertically at one end, in the one-hundred fortieth embodiment, a piezoelectric bimorph element  47025  is entirely bonded horizontally to the reverse side of a linking unit  47027  so as to have the same vibration direction as in the one-hundred thirty-ninth embodiment. A second difference is that the linking unit  47027  which links together the right-ear cartilage conduction unit  47024  and the left-ear cartilage conduction unit  47026  and to which the piezoelectric bimorph element  47025  is bonded over an entire surface thereof is located under the top frame  8227 , and does not appear in the exterior appearance of the mobile telephone  47001 . A third difference is that inner middle parts of the right-ear cartilage conduction unit  47024  and the left-ear cartilage conduction unit  47026  connect, respectively via openings provided in opposite corner parts of the linking unit  47027 , to the linking unit  47027  inside the mobile telephone  47001  so as to be integral with it. This structure will be described in detail below. 
       FIG. 226(A)  is a front perspective view of the one-hundred fortieth embodiment. There, as described above, unlike in  FIG. 222(A)  showing the one-hundred thirty-sixth embodiment, the linking unit  47027  which links together the right-ear cartilage conduction unit  47024  and the left-ear cartilage conduction unit  47026  is located under the top frame  8227 , and does not appear in the exterior appearance of the mobile telephone  47001 . 
       FIG. 226(B)  corresponds to a sectional view along line B 1 -B 1  in  FIG. 226(A) . As will be clear from  FIG. 226(B) , in the one-hundred fortieth embodiment, the right-ear cartilage conduction unit  47024  and the left-ear cartilage conduction unit  47026  are, via openings formed such that part of the top frame  8227  penetrates middle parts of opposite corner parts respectively, formed integrally with the linking unit  47027  inside the mobile telephone  47001 . The linking unit  47027  is bonded to the reverse side of the top frame  8227 . The piezoelectric bimorph element  47025  is supported by being entirely bonded horizontally to the bottom face of the linking unit  47027 . Its vibration direction is, as in the one-hundred thirty-ninth embodiment, perpendicular to the top frame  8227  (in the up/down direction in the mobile telephone  47001 ). Thus, the vibration of the entire piezoelectric bimorph element  47025  conducts to the linking unit  47027 , and this vibration is conducted to each of the right-ear cartilage conduction unit  47024  and the left-ear cartilage conduction unit  47026 . 
       FIG. 226(C)  is a top view of the  FIG. 226(A) . As described above, the linking unit  47027 , which integrally links together the right-ear cartilage conduction unit  47024  and the left-ear cartilage conduction unit  47026 , does not appear in the exterior appearance. Moreover, the piezoelectric bimorph element  47025  entirely affixed to the linking unit  47027  housed inside is indicated by broken lines. Also indicated by broken lines are the corner parts  8227   a  and  8227   b  of the top frame  8227  excluding the openings formed so as to penetrate their middle parts to introduce the right-ear cartilage conduction unit  47024  into the mobile telephone  47001 , and the corner parts  8227   c  and  8227   d  of the top frame  8227  excluding the openings formed so as to penetrate their middle parts to introduce the left-ear cartilage conduction unit  47026  into the mobile telephone  47001 . The structure around here will be further described later. 
     Also in  FIG. 226(D) , which is a sectional view along line B 2 -B 2  shown in  FIGS. 226(A) to 226(C) , it is seen how the linking unit  47027  is affixed to the bottom side of the top frame  8227  and how the piezoelectric bimorph element  47025  is affixed to it so as to point upward. Moreover, as will be clear from  FIGS. 226(B) and 226(D) , in the one-hundred fortieth embodiment, as in the one-hundred thirty-ninth embodiment, the vibration direction of the piezoelectric bimorph element  47025  is perpendicular to the top frame  8227 . This is one those arrangements which require the least space inside the mobile telephone  47001 , and is suitable to introduce a cartilage conduction structure in a top part of the mobile telephone  47001  where a large number of members are arranged. 
       FIG. 226(E)  is a partial sectional view near the right-ear cartilage conduction unit  47024  at another section parallel to  FIG. 226(B) . The partial sectional view in  FIG. 226(E)  shows a section near where the front end face of the top frame  8227  abuts the front plate  8201   a , avoiding an opening through which a power switch  8209  appearing in the sectional view in  FIG. 226(B)  is inserted and an opening through which the right-ear cartilage conduction unit  47024  is connected to the linking unit  47027 . As will be clear from the  FIG. 226(E) , in the part other than the opening formed so as to penetrate a middle part to lead the right-ear cartilage conduction unit  47024  into the mobile telephone  47001 , the top-face and side-face parts of the top frame  8227  are continuous in the corner part  8227   h , and the right-ear cartilage conduction unit  47024  is provided so as to cover the so configured corner part  8227   b  of the top frame  8227 . A section near where the rear end face of the top frame  8227  abuts the back plate  8201   b  is similar to that shown in  FIG. 226(E) . While  FIG. 226(E)  shows the structure around the right-ear cartilage conduction unit  47024 , the structure around the left-ear cartilage conduction unit  47026  is similar. 
     Also in the one-hundred fortieth embodiment configured as described above, the piezoelectric bimorph element  47025  is affixed to the linking unit  47027  so as to be supported only by the linking unit  47027 , and vibration conducts via the right-ear cartilage conduction unit  47024  or the left-ear cartilage conduction unit  47026  integrally molded to it to the ear cartilage. This achieves efficient cartilage conduction. Moreover, also in the one-hundred fortieth embodiment, as in the embodiments described previously, generation of air-conduction sound resulting from vibration of the front plate  8201   a  or the back plate  8201   b , or of the top frame  8227 , is suppressed. The linking unit  47027  is located inward of the top frame  8227 , and thus hardly contributes to generation of air-conduction sound. Also obtained as in the embodiments described previously are the benefits of, in case the mobile telephone  47001  is dropped, the two corner parts being protected by the elastic member, and the piezoelectric bimorph element  47025  itself being protected by the elastic member&#39;s shock-absorbing property. 
     One-Hundred Forty-First Embodiment 
       FIG. 227  comprises a perspective view and sectional views of a one-hundred forty-first embodiment according to one aspect of the present invention, which is configured as a mobile telephone  48001 . The one-hundred forty-first embodiment too has much in common with the one-hundred thirty-sixth embodiment in  FIG. 222 ; therefore, common parts are identified by the same reference numerals, and no overlapping description will be repeated unless necessary. A first difference of the one-hundred forth-first embodiment in  FIG. 227  from the one-hundred thirty-sixth embodiment in  FIG. 222  is that, whereas in the one-hundred thirty-sixth embodiment a piezoelectric bimorph element  13025  is used as a cartilage conduction vibration source, in the one-hundred forty-first embodiment, as in the eighty-eighth embodiment in  FIG. 136  for instance, an electromagnetic vibrating element  48025  is used as a cartilage conduction vibration source. A second difference is that the right-ear cartilage conduction unit  48024  and the left-ear cartilage conduction unit  48026  are arranged to cover opposite corner parts of the top face of the mobile telephone  48001  and, continuous with them, the linking unit  48027  too is arranged to cover the top-face part of the mobile telephone  48001 . A more specific description follows. 
       FIG. 227(A)  is a front perspective view of the one-hundred forty-first embodiment. As described above, in the one-hundred forty-first embodiment, unlike in  FIG. 222(A)  showing the one-hundred thirty-sixth embodiment, a configuration is adopted in which the right-ear cartilage conduction unit  48024 , the left-ear cartilage conduction unit  48026 , and the linking unit  48027  which links them together are configured such that they as a whole cover the top-face part of the mobile telephone  48001 . 
       FIG. 227(B)  corresponds to a sectional view along line B 1 -B 1  in  FIG. 227(A) . As will be clear from  FIG. 227(B) , as in the one-hundred thirty-sixth embodiment, on the bottom of the linking unit  48027 , which links together the right-ear cartilage conduction unit  48024  and the left-ear cartilage conduction unit  48026 , there is provided an extension part  48027   c  which penetrates through an opening provided in the top frame  8227  to extend into the mobile telephone  48001 . The electromagnetic vibrating element  48025  is supported by being embedded in the extension part  48027   c . Thus, the vibration of the electromagnetic vibrating element  48025  conducts to the extension part  48027   c , and this vibration is conducted via the linking unit  48027  to each of the right-ear cartilage conduction unit  48024  and the left-ear cartilage conduction unit  48026 . In the one-hundred forty-first embodiment, the linking unit  48027  is formed broadly to cover the top-face part of the mobile telephone  48001 , and this results in a broader conduction path for vibration. Moreover, even with the middle of the top-face part of the mobile telephone  48001  put on the ear cartilage as with a common mobile telephone, the vibration of the linking unit  48027  conducts to the ear cartilage, and thus cartilage conduction is achieved. In this way, in the one-hundred forty-first embodiment, the linking unit  48027  too acts as a cartilage conduction unit. 
       FIG. 227(C)  is a top view of  FIG. 227(A) , and there it is seen that, as described above, the right-ear cartilage conduction unit  48024 , the left-ear cartilage conduction unit  48026 , and the linking unit  48027 , which are formed integrally, as a whole cover the top-face part of the mobile telephone  48001 . The extension part  48027   c  and the electromagnetic vibrating element  48025  embedded in it, which are housed inside, are indicated by broken lines. Also in  FIG. 227(D) , which is a sectional view along line B 2 -B 2  shown in  FIGS. 227(A) to 227(C) , it is seen that the linking unit  48027  and the extension part  48027   c  are formed integrally. 
     Also in the one-hundred forty-first embodiment, the electromagnetic vibrating element  48025  as a cartilage conduction vibration source is embedded in the extension part  48027   c  so as to be supported only by the linking unit  48027 , and vibration is conducted via the right-ear cartilage conduction unit  48024  or the left-ear cartilage conduction unit  48026  integrally molded to it to the ear cartilage. This achieves efficient cartilage conduction. Moreover, also in the one-hundred forty-first embodiment, as in the embodiments described previously, generation of air-conduction sound resulting from vibration of the front plate  8201   a  or the back plate  8201   b , and generation of air-conduction sound from the linking unit  48027 , the right-ear cartilage conduction unit  48024 , and the left-ear cartilage conduction unit  48026  themselves, are both suppressed. Also obtained likewise are the benefits of, in case the mobile telephone  48001  is dropped, the two corner parts being protected by the elastic member, and the electromagnetic vibrating element  48025  itself as a cartilage conduction vibration source being protected by the elastic member&#39;s shock-absorbing property. 
     The features of the present invention in the embodiments described above are not limited to those specific embodiments; they can be implemented in any other embodiment so long as they provide their advantages. For example, the specific features described in connection with the one-hundred thirty-sixth to one-hundred forty-first embodiments are not necessarily unique to the respective embodiments, but features from different embodiments can be implemented in combination. For example, the configuration of the right-ear cartilage conduction unit  48024 , the left-ear cartilage conduction unit  48026 , and the linking unit  48027  in the one-hundred forty-first embodiment, where they together cover the entire top-face part of the mobile telephone  48001 , can be adopted in the one-hundred thirty-sixth embodiment. Conversely, the configuration of the right-ear cartilage conduction unit  45024 , the left-ear cartilage conduction unit  45026 , and the linking unit  45027  in the one-hundred thirty-eighth embodiment can be adopted in the one-hundred forty-first embodiment. 
     In a case where, as in the one-hundred forty-first embodiment in  FIG. 227 , a cartilage conduction vibration source is supported by being embedded in the linking unit  48027 , provided that the cartilage conduction vibration source is sufficiently thinner than the linking unit  48027 , the cartilage conduction vibration source may be supported on the outer side (top side) of the top frame  8227  with no opening formed in the top frame  8227 . Also with this structure, owing to the cartilage conduction vibration source being embedded in the linking unit  48027 , the cartilage conduction vibration source can be supported so as not to make contact with the casing top-face part of the mobile telephone  48001  (the top frame  8227 ). In a case where a cartilage conduction vibration source is embedded in the linking unit, as the cartilage conduction vibration source, not only an electromagnetic vibrating element as in the one-hundred forty-first embodiment but also a piezoelectric bimorph element as in other embodiments can be adopted. Conversely, in the one-hundred thirty-sixth to one-hundred fortieth embodiments, as the cartilage conduction vibration source, an electromagnetic vibrating element as in the one-hundred forty-first embodiment can be adopted. 
     One-Hundred Forty-Second Embodiment 
       FIG. 228  comprises a perspective view and sectional views of a one-hundred forty-second embodiment according to one aspect of the present invention, which is configured as a mobile telephone  49001 . The one-hundred forty-second embodiment has much in common with the one-hundred fortieth embodiment in  FIG. 226 ; therefore, common parts are identified by the same reference numerals, and no overlapping description will be repeated unless necessary. The one-hundred forty-second embodiment in  FIG. 228  differs from the one-hundred fortieth embodiment in  FIG. 226  in that a piezoelectric bimorph element  47025  is supported on a linking unit  47027  via a hard vibration-conducting plate  49027  having a good vibration-conducting property. This will be described below in detail. 
     As shown in  FIG. 228(A) , which is a front perspective view, the exterior appearance of the one-hundred forty-second embodiment is the same as the exterior appearance of the one-hundred fortieth embodiment shown in  FIG. 226(A) , and therefore no overlapping description will be repeated.  FIG. 228(B)  corresponds to a sectional view along line B 1 -B 1  in  FIG. 228(A) . As will be clear from  FIG. 228(B) , in the one-hundred forty-second embodiment, a hard vibration-conducting plate  49027  which has a better vibration-conducting property than the linking unit  47027  is affixed to the reverse side of the linking unit  47027  which is an elastic member, and the piezoelectric bimorph element  47025  is supported by being affixed to the reverse side of the hard vibration-conducting plate  49027 . As will be understood from  FIG. 228(B) , opposite ends of the hard vibration-conducting plate  49027  are extended along the reverse side of the linking unit  47027  and are inserted into the right-ear cartilage conduction unit  47024  and the left-ear cartilage conduction unit  47026  respectively. Although in  FIG. 228(B)  the hard vibration-conducting plate  49027  appears to be discontinuous on the way from the piezoelectric bimorph element  47025  to the left-ear cartilage conduction unit  47026 , this is because the illustrated section passes through the hole that is formed in the hard vibration-conducting plate  49027  to avoid contact with an external earphone jack  8246 . Except for the hole, the hard vibration-conducting plate  49027  is continuous from the piezoelectric bimorph element  47025  to the left-ear cartilage conduction unit  47026 . Likewise, the hard vibration-conducting plate  49027  is not discontinuous on the way from the piezoelectric bimorph element  47025  to the right-ear cartilage conduction unit  47024 . Except for the hole that is formed in the hard vibration-conducting plate  49027  to avoid a power switch  8209 , the hard vibration-conducting plate  49027  is continuous from the piezoelectric bimorph element  47025  to the right-ear cartilage conduction unit  47024 . 
     With the configuration described above, the vibration of the piezoelectric bimorph element  47025  is conducted to the right-ear cartilage conduction unit  47024  and the left-ear cartilage conduction unit  47026  not only via the linking unit  47027  but also via the hard vibration-conducting plate  49027 . As will be described in detail below, the hard vibration-conducting plate  49027  makes contact only with the right-ear cartilage conduction unit  47024  and the left-ear cartilage conduction unit  47026 , and does not conduct vibration directly to the front plate  8201   a , the back plate  8201   b , and the top frame  8227 . Even when the mobile telephone  49001  is dropped and impact is applied from outside to the front plate  8201   a , the back plate  8201   b , and the top frame  8227 , owing to the interposition of the linking unit  47027 , the right-ear cartilage conduction unit  47024 , and the left-ear cartilage conduction unit  47026 , which are elastic members, between the hard vibration-conducting plate  49027  and the piezoelectric bimorph element  47025  supported on it, the impact is alleviated, and the piezoelectric bimorph element  47025  is prevented from destruction. 
       FIG. 228(C)  is a top view of  FIG. 228(A) . As indicated by broken lines, the hard vibration-conducting plate  49027  is inserted in each of the right-ear cartilage conduction unit  47024  and the left-ear cartilage conduction unit  47026  without making contact with the front plate  8201   a  or the back plate  8201   b . Moreover, the hard vibration-conducting plate  49027  has a hole  49027   a  so as not to make contact with the external earphone jack  8246 . Moreover, the hard vibration-conducting plate  49027  has a rectangular hole so as not to make contact with the power switch  8209 . Thus, the vibration that has been conducted from the piezoelectric bimorph element  47025 , which is indicated by broken lines, to the hard vibration-conducting plate  49027  is transmitted directly only to the linking unit  47027 , the right-ear cartilage conduction unit  47024 , and the left-ear cartilage conduction unit  47026 . 
     Also in  FIG. 228(D) , which is a sectional view along line B 2 -B 2  shown in  FIGS. 228(A) to 228(C) , it is seen that the hard vibration-conducting plate  49027  does not make contact with the front plate  8201   a  or the back plate  8201   b .  FIG. 228(E)  shows a section near where the front end face of the top frame  8227  makes contact with the front plate  8201   a , near the right-ear cartilage conduction unit  47024 , at another section parallel to  FIG. 228(B) . Also in  FIG. 228(E) , it is seen that no section of the hard vibration-conducting plate  49027  appears near where it makes contact with the front plate  8201   a , and that the hard vibration-conducting plate  49027  does not make contact with the front plate  8201   a.    
     Through precise measurement of the frequency characteristics of the sound pressure inside the external auditory meatus ascribable to cartilage conduction, it has been observed that, when a cartilage conduction unit is in contact with the ear cartilage, depending on conditions, a valley appears around 1.5 kHz where the pressure level is low. The valley appears especially when there is a large direct air-conduction sound component that originates in the cartilage conduction unit and enters the external auditory meatus through its entrance. 
     In the one-hundred forty-second embodiment in  FIG. 228 , as described above, via the hard vibration-conducting plate  49027 , the vibration of the piezoelectric bimorph element  47025  is conducted to the right-ear cartilage conduction unit  47024  and the left-ear cartilage conduction unit  47026 , and in addition the hard vibration-conducting plate  49027  is arranged so as not to make contact with the front plate  8201   a  in order to suppress generation of air-conduction sound from the front plate  8201   a . Thus, when the right-ear cartilage conduction unit  47024  or the left-ear cartilage conduction unit  47026 , which is a corner part of the mobile telephone  49001 , is put somewhere around the entrance of the external auditory meatus, cartilage conduction occurs from the right-ear cartilage conduction unit  47024  or the left-ear cartilage conduction unit  47026 , which constitutes the top and side faces of the corner part, to the ear cartilage, augmenting the cartilage air-conduction sound component while diminishing the direct air-conduction sound component from the front plate  8201   a  constituting the front face of the corner part and facing the entrance of the external auditory meatus. A configuration like this where vibration is conducted from the top and side faces of a corner part of the mobile telephone  49001  to the ear cartilage while direct air-conduction sound from the front face of the corner part is suppressed is beneficial to preventing a valley of sound pressure appearing around 1.5 kHz as mentioned above. 
     One-Hundred Forty-Third Embodiment 
       FIG. 229  comprises a perspective view and sectional views of a one-hundred forty-third embodiment according to one aspect of the present invention, which is configured as a mobile telephone  50001 . The one-hundred forty-third embodiment has much in common with the one-hundred forty-second embodiment in  FIG. 228 ; therefore, common parts are identified by the same reference numerals, and no overlapping description will be repeated unless necessary. The one-hundred forty-third embodiment in  FIG. 229  differs from the one-hundred forty-second embodiment in  FIG. 228  in that no linking unit  47027  is provided and a hard vibration-conducting plate  49027  which supports a piezoelectric bimorph element  50025  and which has a good vibration-conducting property is supported only by the right-ear cartilage conduction unit  47024  and the left-ear cartilage conduction unit  47026 . This will be described below. 
     The exterior view in  FIG. 229(A)  is the same as  FIG. 228(A) , which shows the exterior appearance of the one-hundred forty-second embodiment. As will be clear from  FIG. 229(B) , which is a sectional view along line B 1 -B 1  in  FIG. 229(A) , in the one-hundred forty-third embodiment, no linking unit  47027  is provided, and the right-ear cartilage conduction unit  47024  and the left-ear cartilage conduction unit  47026  are provided separately in corner parts respectively. The hard vibration-conducting plate  49027 , which supports the piezoelectric bimorph element  50025 , floats off the top frame  8227 , and is supported only by the right-ear cartilage conduction unit  47024  and the left-ear cartilage conduction unit  47026 . As in the one-hundred forty-second embodiment, in the one-hundred forty-third embodiment, the hard vibration-conducting plate  49027  is formed of a material having a better vibration-conducting property than the right-ear cartilage conduction unit  47024  and the left-ear cartilage conduction unit  47026 . In the one-hundred forty-third embodiment, as in the one-hundred forty-second embodiment, vibration does not directly conduct from the hard vibration-conducting plate  49027  to the front plate  8201   a , the back plate  8201   b , or the top frame  8227 . Also as in the one-hundred forty-second embodiment, when impact is applied from outside to the front plate  8201   a , the back plate  8201   b , or the top frame  8227 , it is alleviated by the right-ear cartilage conduction unit  47024  and the left-ear cartilage conduction unit  47026 , which are elastic members, and the piezoelectric bimorph element  50025  is prevented from destruction. 
     As will be understood from  FIG. 229(C) , which is a top view of  FIG. 229(A) , also in the one-hundred forty-third embodiment, the hard vibration-conducting plate  49027  is supported by the right-ear cartilage conduction unit  47024  and the left-ear cartilage conduction unit  47026  from opposite sides without making contact with the front plate  8201   a , the back plate  8201   b , the external earphone jack  8246 , or the power switch  8209 . As will be understood from  FIG. 229(C) , in the one-hundred forty-third embodiment, to obtain well-balanced vibration even with the hard vibration-conducting plate  49027  floating off the top frame  8227 , the piezoelectric bimorph element  50025  is arranged at about the middle of the top face. 
     Also in  FIG. 229(D) , which is a sectional view along line B 2 -B 2  shown in  FIGS. 229(A) to 229(C) , it is seen that the hard vibration-conducting plate  49027  does not make contact with the front plate  8201   a  or the back plate  8201   b , and that it floats off the top frame  8227 . Also in  FIG. 229(E) , which is a sectional view similar to  FIG. 228(E)  showing the one-hundred forty-second embodiment, it is seen that the hard vibration-conducting plate  49027  does not make contact with the front plate  8201   a.    
     One-Hundred Forty-Forth Embodiment 
       FIG. 230  is a schematic diagram of a one-hundred forty-forth embodiment according to one aspect of the present invention, which is configured as stereo earphones.  FIG. 230(A)  to (C) showing the one-hundred forty-forth embodiment have much in common with  FIGS. 209(A)  the (C) showing the one-hundred thirty-first embodiment. Therefore, common parts are identified by the same reference numerals, and no overlapping description will be given unless necessary. However, the following should be noted: in the one-hundred forty-forth embodiment, there is provided no vibration plate (diaphragm) as in the one-hundred thirty-first embodiment, and the basic configuration here is rather a simple one where, as in the one-hundred ninth embodiment in  FIG. 182 , a passage hole  51024   a  is formed in a cartilage conduction unit  51024  formed of an elastic member. 
     One feature of the one-hundred forty-forth embodiment in  FIG. 230  is that, as will be clear from a sectional view in  FIG. 230(C) , a hard-material layer  51027  is affixed to the face (in  FIG. 230(A) , the front face) of the earphone which faces the entrance of the external auditory meatus when the earphone is worn and to the inner face of the passage hole  51024   a . In  FIG. 230 , for the sake of emphasis, the hard-material layer  51027  is illustrated to be extremely thick; in reality, it is a layer that is formed to be comparatively thin. The hard-material layer  51027  serves to make the acoustic impedance of the front face of the cartilage conduction unit  51024  and the inner face of the passage hole  51024   a  different from that of the cylindrical side circumferential face of the cartilage conduction unit  51024 , and to suppress vibration of these faces. As a result, when the earphone is worn on the ear, the contact between the cylindrical side circumferential face of the cartilage conduction unit  51024  and the cartilage around the entrance of the external auditory meatus yields a satisfactory air-conduction sound component, and simultaneously suppresses the direct air-conduction sound component from the front face of the cartilage conduction unit  51024  and the inner face of the passage hole  51024   a . This configuration is useful to preventing the previously mentioned valley of sound pressure occurring around 1.5 kHz. 
     The above-described features of the present invention are not limited to the embodiments specifically described above, but can be implemented in any other embodiment so long as they provide their benefits. For example, in the one-hundred forty-second embodiment shown in  FIG. 228 , the piezoelectric bimorph element  50025  may be arranged at about the middle of the top face as in the one-hundred forty-third embodiment. 
     Although in the one-hundred forty-forth embodiment shown in  FIG. 230 , the hard-material layer is affixed to the face that faces the entrance of the external auditory meatus when the earphone is worn and to the inner face of the passage hole, the hard-material layer may instead be affixed to only one of those faces. The direct air-conduction sound component from the front face of the cartilage conduction unit or from the inner face of the passage hole may be suppressed by any other means than affixation of a hard-material layer. For example, as for the front face, it is possible to adopt a means such as giving it a structure different from the cylindrical side circumferential face which makes contact with the ear cartilage (e.g., giving the part in contact with the ear cartilage a smooth surface and the other part a coarse surface, or adopting a two-part structure where a front-face part is separated across a gap such that its surface does not vibrate even when the interior vibrates). For the inner face of the passage hole, it is possible to adopt a means such as giving it directivity pointing outside the external auditory meatus. 
     One-Hundred Forty-Fifth Embodiment 
       FIG. 231  comprises a perspective view, sectional views, a top view, and a side view of a one-hundred forty-fifth embodiment according to one aspect of the present invention, which is configured as a mobile telephone  52001 . The one-hundred forty-fifth embodiment has much in common with the one-hundred seventh embodiment in  FIG. 178 ; therefore, common parts are identified by the same reference numerals, and no overlapping description will be repeated unless necessary. The one-hundred forty-fifth embodiment in  FIG. 231  differs from the one-hundred seventh embodiment in  FIG. 178  in the structure with which the top frame  8227  is fitted. Specifically, an elastic member  52065  is provided not only between the top frame  8227  and the right and left frames  8201   c  and  8201   e  but also between the top frame  8227  and the front and back plates  8201   a  and  8201   b , making it difficult for the vibration of the top frame  8227  to conduct to other casing segments. The piezoelectric bimorph element  50025  as a vibration source is, for example, a compact one as in the one-hundred forty-third embodiment in  FIG. 229 , and is affixed directly to the inner side of the top frame  8227 . 
     A perspective view in  FIG. 231(A)  shows the above-described structure. The elastic member  52065  is provided around the circumference of the top frame  8227  so as to be interposed between it and each of the right frame  8201   c , the left frame  8201   e , the front plate  8201   a , and the back plate  8201   b . Thus, the vibration of the top frame  8227  is less prone to conduct to those frames and plates. 
     As will be clear from  FIG. 231(B) , which is a sectional view along line B 1 -B 1  in  FIG. 231(A) , the compact piezoelectric bimorph element  50025  is affixed directly to the inner face of the top frame  8227 . In  FIG. 231(C) , which is a top view, it is seen that the elastic member  52065  is interposed between the top frame  8227  and each of the front and back plates  8201   a  and  8201   b . Also in  FIG. 231(D) , which is a sectional view along line B 2 -B 2  in  FIGS. 231(A) to 231(C) , it is seen that the elastic member  52065  is interposed between the top frame  8227  and each of the front and back plates  8201   a  and  8201   b  so that these do not make direct contact with each other. Furthermore, in  FIG. 231(E) , which is a left side view of  FIG. 231(A) , it is seen that the elastic member  52065  is interposed between a left corner part  8226  of the top frame  8227  and each of the left frame  8201   e  and the front and back plates  8201   a  and  8201   b  so that these do not make direct contact with each other. 
     One-Hundred Forty-Sixth Embodiment 
       FIG. 232  comprises a perspective view and top views of a one-hundred forty-sixth embodiment according to one aspect of the present invention, which is configured as a mobile telephone  53001 . The one-hundred forty-sixth embodiment has much in common with the one-hundred forty-second embodiment in  FIG. 228 ; therefore, common parts are identified by the same reference numerals, and no overlapping description will be repeated unless necessary. Sectional views too are largely common, and therefore overlapping illustration and description will be omitted. The one-hundred forty-sixth embodiment in  FIG. 232  differs from the one-hundred forty-second embodiment in  FIG. 228  in that it has a means for switching air-conduction sound generation like the one in the forty-ninth embodiment in  FIG. 74 . However, its specific configuration here differs greatly, as will be described below. 
     As shown in a perspective view in  FIG. 232(A) , a slot  53027   a  is provided in the top frame  8227  so that an air-conduction sound generation switching operation unit  53027   b  is slidable along the slot  53027   a .  FIG. 232(A)  shows a state where no air-conduction sound is generated. In this state, the one-hundred forty-sixth embodiment functions in the same way as the one-hundred forty-second embodiment in  FIG. 228 . On the other hand, sliding the air-conduction sound generation switching operation unit  53027   b  leftward along the slot  53027   a  brings into effect a state where air-conduction sound is generated. In this state, air-conduction sound fulfilling a predetermined standard of the mobile telephone is generated from a top part of the front plate  8201   a . The air-conduction sound generation switching operation unit  53027   b  is configured to be stably held in either position by an unillustrated click mechanism. 
       FIG. 232(B)  is a top view of the mobile telephone  53001  in the state where no air-conduction sound is generated. As will be clear from  FIG. 232(B) , in a part of the hard vibration-conducting plate  49027  near the front plate  8201   a , a notch  49027   a  is provided, and at a position corresponding to the notch  49027   a , a movable wedge  53027  is provided. The movable wedge  53027  is configured to be slidable along with the air-conduction sound generation switching operation unit  53027   b , and in the state in  FIG. 232(B) , the movable wedge  53027  is apart from the notch  49027   a . Thus, the vibration of the top frame  8227  does not conduct to the front plate  8201   a.    
       FIG. 232(C)  is a top view of the mobile telephone  53001  in the state where air-conduction sound is generated. As will be clear from  FIG. 232(C) , the movable wedge  53027  moves leftward along with the air-conduction sound generation switching operation unit  53027   b , and wedges between the notch  49027   a  and the top frame  8227 . Thus, the vibration of the top frame  8227  conducts to the front plate  8201   a , and the entire front plate  8201   a  (in particular, a top part put on the ear) vibrates to generate predetermined air-conduction sound. 
     Even in the state shown in  FIG. 232(C) , with a corner put on the ear cartilage, a call can be conducted by cartilage conduction. In this case, the direct air-conduction sound resulting from the vibration of a corner part of the front plate  8201   a  enters the earhole, and thus the heard sound has a high-frequency component added to the direct air-conduction sound. Accordingly, the switching configuration of the one-hundred forty-sixth embodiment can be applied to frequency characteristics switching based on language, which will be described later. 
     As described above, like the one-hundred forty-second embodiment in  FIG. 228 , the one-hundred forty-sixth embodiment in  FIG. 232  allows calls by cartilage conduction, and in addition, as necessary, also allows calls by air-conduction sound as conventionally practiced. Thus, a standard for common mobile telephones can be met. Moreover, a user can, as he likes, usually use the mobile telephone in the state in  FIG. 232(C)  as an ordinary one, switching to the state in  FIG. 232(B)  when outside noise is so loud that he finds difficulty hearing in the ordinary state, or conversely when the ambience is so quiet that he wants to prevent the sound that leaks by air conduction from sounding annoying or revealing personal information. As shown in  FIGS. 232(B)  and (C), for efficient air-conduction sound generation, the piezoelectric bimorph element  50025  is arranged closer to the front plate  8201   a.    
     One-Hundred Forty-Seventh Embodiment 
       FIG. 233  is a block diagram showing a one-hundred forty-seventh embodiment according to one aspect of the present invention, which is configured as a mobile telephone. The block diagram showing the one-hundred forty-seventh embodiment has much in common with the block diagram of the cartilage conduction vibration source device of the eighty-second embodiment shown in  FIG. 122 ; therefore, the configuration of the latter is partly shared here, with common parts identified by the same reference numerals and overlapping description omitted. A feature of the embodiment in  FIG. 233  is that it is provided with a means for performing switching based on a difference in language in the cartilage conduction that is exploited in a call conducted on the mobile telephone. 
     For example, between Japanese and English, vowels and consonants contribute to the language in different degrees. It is believed that, in Japanese, in which vowels contribute in a high degree, more information is distributed in a comparatively low frequency range; by contrast, in English, in which consonants contribute in a high degree, more information is distributed in a comparatively high frequency range. It is believed that, also in Chinses, more information is distributed in a comparatively high frequency range. 
     To cope with such a difference, in the one-hundred forty-seventh embodiment, a drive circuit  54003  for a piezoelectric bimorph element  7013  is provided with a digital sound processing circuit  54038 , and the piezoelectric bimorph element  7013  is made to vibrate for cartilage conduction in different frequency ranges for different languages. Specifically, the digital sound processing circuit  54038  is provided with a Japanese-language equalizer  54038   a , a standard equalizer  54038   b , and an English-language equalizer  54038   c , and these are switched appropriately by a switching unit  54038   d  which is controlled by an application processor  54039  so that an output from one of them is fed to a DA conversion circuit  7138   c . Here, “Japanese” and “English” in the Japanese-language equalizer  54038   a  and the English-language equalizer  54038   c  are simply representative of particular types of languages; for example, the English-language equalizer  54038   c  can be used also for Chinese, which is believed to have more information distributed in a comparatively high frequency range. The standard equalizer  54038   b  is intermediate between the two equalizers. Cartilage conduction occurs more easily at comparatively low frequencies. Accordingly, the Japanese-language equalizer  54038   a  reduces the sound volume to somewhat below the standard while slightly cutting down components in a high-frequency range; the English-language equalizer  54038   c  raises the sound volume to above the standard and thereby augments components in a high-frequency range while attenuating components in a low-frequency range. 
     The application processor  54039  controls the common mobile telephone functions, and in addition controls the switching unit  54038   d  according to different conditions. Specifically, Based on an equalizer switching operation done on the manual operation unit  54009 , the application processor  54039  feeds a switching control signal to the switching unit  54038   d . An operation on the manual operation unit  54009  overrides switching based on any other condition, and therefore whenever a user finds a result of automatic switching, described later, inappropriate, he can change it manually. 
     The manual operation unit  54009  further allows manual switching of the display language on the display unit  41005 . Based on a display language switching operation, the application processor  54039  controls a display driver  54041  to switch the display language on the display unit  41005 . In coordination with the display language switching operation on the display unit  41005 , the application processor  54039  feeds a switching control signal to the switching unit  54038   d . Conversely, the application processor  54039  can switch the display language in coordination with an equalizer switching operation when this is done manually. Whether to enable or disable the coordination can be set previously. 
     The application processor  54039  also feeds a switching control signal to the switching unit  54038   d  based on a change in language region detected by a GPS unit  54049 . The application processor  54039  also feeds a switching control signal to the switching unit  54038   d  based on a result of inference by an incoming-call language inferring sound analyzer  50039   a  which analyzes incoming-call sound from a telephone function unit  54045 . The incoming-call language inferring sound analyzer  50039   a  performs its function by, for example, checking whether or not the incoming-call sound contains particular consonants or vowels, particular words, or the like through matching with previously stored standard sound element patterns, and analyzing the intonation and rhythm of the incoming-call sound. Based on one or a combination of those criteria, the incoming-call language inferring sound analyzer  50039   a  infers the incoming-call language and calculates the probability to confirm the inference if sufficiently probable. The incoming-call language inferring sound analyzer  50039   a  is not necessarily intended to infer one language, but is intrinsically intended to decide which of the Japanese-language equalizer  54038   a , the standard equalizer  54038   b , and the English-language equalizer  54038   c  to adopt. When the probability of the inference is so low that the incoming-call language cannot be determined, no change is made from the currently set equalizer; or in such a case, the standard equalizer  54038   b  may be adopted. 
       FIG. 234  is a flow chart showing the operation of the application processor  54039  in the one-hundred forty-seventh embodiment in  FIG. 233 . The flow in  FIG. 234  is intended to illustrate mainly the control for language switching and thus focuses on operation for functions related to it; in reality, the application processor  54039  involves operation other than that shown in  FIG. 234 , such as the functions of an common mobile telephone. The flow in  FIG. 234  starts when the main power to the mobile telephone is turned on. In Step S 942 , as to the language equalizer and the display language, initial settings are put into effect. The initial settings can be previously selected by a user. For example, in a case where the mobile telephone is used by a Japanese user in Japan, the Japanese-language equalizer  54038   a  can be selected, and the display language on the display unit  41005  is set to Japanese. 
     Next, in Step S 944 , it is checked whether or not a manual operation for switching the equalizer has been done. If no such operation has been done, then, in Step S 946 , it is checked whether or not a mode in which the language equalizer is changed automatically is previously set. If the automatic change mode is set, then, in Step S 948 , it is checked whether or not a manual operation for switching the display language has been done. If no manual operation for switching the display language has been done, then, in Step S 950 , it is checked, based on a detection signal from the GPS unit  54049 , whether or not, as a result of movement of the mobile telephone, a geographical change has occurred from the currently set language region to another language region. If no geographical change in language region has occurred, the flow advances to Step S 952 . 
     In Step S 952 , the incoming-call language inferring sound analyzer  50039   a  performs the incoming-call language inferring process. The content is as described above with reference to the block diagram in  FIG. 233 . On completion of the incoming-call language inferring process, in Step S 954 , whether or not the inference of a language in Step S 954  has been confirmed. If the inference has been confirmed, then, in Step S 956 , it is checked whether or not a change has occurred from the currently set language to the inferred language. If a change to the inferred language is recognized, then the flow advances to Step S 958 . On the other hand, also if, in Step S 950 , a change in GPS language region has been detected, the flow advances to Step S 958 . If, in Step S 948 , a display language switching manual operation is detected, then first, in Step S 960 , switching to the display language reflecting the manual operation is performed, and then the flow advances to Step S 958 . 
     In Step S 958 , it is checked whether or not a predetermined time (e.g., 30 minutes) has passed after the equalizer switching manual operation on the manual operation unit  54009 . If the predetermined time has passed, then, in Step S 962 , language equalizer switching is performed, and the flow then advances to Step S 964 . The function in Step S 962  includes not performing switching even when the language has been changed if the applicable language equalizer has remained unchanged. 
     In Step S 964 , the display language is switched. Unlike with the equalizer, as for the display language, when the language changes, the display language is switched. Here, the aim of switching the display language always in coordination with the switching of the language equalizer in the automatic language equalizer change mode is to notify a user that the language equalizer has been changed automatically to prompt the user, if he finds the result inappropriate, to correct manually. As described above, when the language has changed, the display language is switched to that language. However, as for the equalizer, even when a change occurs between languages with similar frequency ranges, the equalizer is not switched. For example, when a change from English to Chinese occurs, the display language is changed but the equalizer is not switched: the English-language equalizer is used with both languages. On completion of the display language switching in Step S 964 , the flow advances to Step S 966 . 
     On the other hand, if, in Step S 954 , the language inference is not confirmed, or if, in Step S 956 , the inferred language is not different from the currently set one, or if, in Step S 958 , the predetermined time has not passed after the equalizer switching manual operation on the manual operation unit  54009 , the flow advances to Step S 966 . A supplementary description of the significance of Step S 958  will now be given. For discussion&#39;s sake, if Step S 958  is not provided, even if a user takes the trouble to manually corrects the equalizer as he likes, when the flow, repeated as will be described later, goes through Step S 960 , S 950 , or S 956 , the automatic change function there automatically restores the equalizer setting before the correction. Owing to the provision of Step S 958  as described above, even when automatic equalizer change is going to be performed as the flow goes through Step S 960 , S 950 , or S 956 , the language equalizer is not switched until the predetermined time passes, but the flow advances directly to Step S 966 . Thus, once the equalizer is switched manually in Step S 944 , the result of the manual switching is maintained for the predetermined time thereafter. 
     If, in Step S 944 , an equalizer switching manual operation has been done (in practice, for the convenience of a user who does not know which equalizer to use for which language, a user is only required to switch the language; accordingly, even when a user does a switching operation, a common language equalizer may continue to be used), the flow advances to Step S 968 , where the language equalizer is switched, and then the flow advances to Step S 970 . The operation in Step S 968  includes continuing to use the same language equalizer even if a language switching operation is done as described above. 
     In Step S 970 , it is checked whether or not a coordinating mode is set in which display switching is coordinated with language switching for equalizer switching. If the coordinating mode is detected to be set, then the flow advances to Step S 972 , where the display language is switched, and then the flow advances to Step S 966 . On the other hand, if, in Step S 970 , the coordinating mode is not detected to be set, the flow advances directly to Step S 966 . This is because, for example when a Japanese user has received an incoming call in English, switching the equalizer may be appropriate but it is not always necessary to change the display language to English. Moreover, unlike with automatic switching, with manual switching, the user himself knows how the switching works, and therefore it is not necessary to change the display language and notify him of the change of equalizer. 
     If, in Step S 946 , the automatic language equalizer change mode is not detected to be previously set, the flow advances directly to Step S 966 . 
     In Step S 966 , it is checked whether or not the main power to the mobile telephone has been turned off. If the main power is not detected to have been turned off, the flow returns to Step S 944 , and thereafter, so long as the main power is not turned off, Steps S 944  through S 972  are repeated to cope with various situational changes related to language switching. On the other hand, if, in Step S 966 , the main power is detected to have been turned off, the flow ends. 
     One-Hundred Forty-Eighth Embodiment 
       FIG. 235  comprises a perspective view and top views of a one-hundred forty-eighth embodiment according to one aspect of the present invention, which is configured as a mobile telephone  54001 . The one-hundred forty-eighth embodiment has much in common with the one-hundred forty-sixth embodiment in  FIG. 232 ; therefore, common parts are identified by the same reference numerals, and no overlapping description will be repeated unless necessary. The one-hundred forty-eighth embodiment in  FIG. 235  has a switching configuration different from the one in the one-hundred forty-sixth embodiment in  FIG. 232 . Moreover, the switching configuration here is suitable for switching for coping with different languages in cartilage conduction as discussed in connection with the one-hundred forty-seventh embodiment in  FIGS. 233 and 234 . However, the switching here is achieved mechanically, rather than by means of circuits, namely equalizers, as in the one-hundred forty-seventh embodiment. 
     As shown in a perspective view in  FIG. 235(A) , due to the switching in the one-hundred forty-eighth embodiment being achieved by means of an internal mechanism, its exterior appearance is substantially the same as in the one-hundred forty-third embodiment in  FIG. 229 .  FIGS. 232(B) and 232(C)  are top views of the mobile telephone  53001 , respectively showing different coupling states of a flexible vibration-conducting plate  54027  with the right-ear and left-ear cartilage conduction units  47024  and  47026 . 
     Specifically,  FIG. 235(B)  shows a state where the coupling between the vibration-conducting plate  54027  and the right-ear and left-ear cartilage conduction units  47024  and  47026  is comparatively shallow. That is, the vibration-conducting plate  54027  has, at opposite ends thereof, movable coupling parts  54027   a  and  54027   b  which move by exploiting the elasticity of the vibration-conducting plate  54027 , and these movable coupling parts  54027   a  and  54027   b , each in a state retracted inward, fit in holes  47024   a  and  47026   a  formed in the right-ear and left-ear cartilage conduction units  47024  and  47026  respectively. Thus, the depth over which the movable coupling parts  54027   a  and  54027   b  fit in is comparatively small. In other words, the vibration of the vibration-conducting plate  54027  is conducted at a position comparatively far away from the surface of the right-ear and left-ear cartilage conduction units  47024  and  47026  which make contact with the ear cartilage, and thus the thickness over which the vibration has to conduct across the elastic cartilage conduction unit is accordingly large. To allow free in-and-out movement of the vibration-conducting plate  54027  relative to the right-ear and left-ear cartilage conduction units  47024  and  47026 , the movable coupling parts  54027   a  and  54027   b  of the vibration-conducting plate  54027  is not bonded to the linking unit  47027 , and is slidable relative to it. 
     By contrast,  FIG. 235(C)  shows a state where the coupling between the vibration-conducting plate  54027  and the right-ear and left-ear cartilage conduction units  47024  and  47026  is comparatively deep. That is, in  FIG. 235(C) , the movable coupling parts  54027   a  and  54027   b , each in a state protruded outward, fit in the holes  47024   a  and  47026   a  formed in the right-ear and left-ear cartilage conduction units  47024  and  47026 . Thus, the depth over which the movable coupling parts  54027   a  and  54027   b  fit in is comparatively large. In other words, the vibration of the vibration-conducting plate  54027  is conducted at a position comparatively close to the surface of the right-ear and left-ear cartilage conduction units  47024  and  47026  which make contact with the ear cartilage, and thus the thickness over which the vibration has to conduct across the elastic cartilage conduction unit is accordingly small. 
     As described above, in the one-hundred forty-eighth embodiment, the length of the elastic cartilage conduction unit that conducts the vibration of the vibration-conducting plate  54027  is changed mechanically so as to change the frequency characteristics of the vibration that reaches the surface of the cartilage conduction unit between  FIG. 238(B)  and  FIG. 235(C) . This structure is useful for mechanically changing the frequency characteristics of cartilage conduction according to language. 
     As mentioned previously, the switching mechanism in the one-hundred forty-sixth embodiment shown in  FIG. 232 , too, can change the level of the air-conduction sound component that enters the earhole by choosing whether or not to vibrate the front plate. Thus, this structure too is useful for mechanically changing the frequency characteristics of cartilage conduction according to language. 
     The above-described features of the present invention are not limited to the embodiment specifically described above, but can be implemented in any other embodiment so long as they provide their benefits. For example, although the one-hundred forty-sixth embodiment shown in  FIG. 232  is described on the basis of the one-hundred forty-second embodiment in  FIG. 228 , it may instead be configured on the basis of the one-hundred forty-third embodiment in  FIG. 229 . 
     Although the one-hundred forty-seventh and one-hundred forty-eighth embodiments shown in  FIGS. 233 to 235  are each configured as a single mobile telephone that is capable of changing frequency characteristics according to language, they may each be configured, instead, so as to provide a plurality of separate mobile telephones having different frequency characteristics corresponding to different languages, in which case each mobile telephone does not need to change frequency characteristics. 
     One-Hundred Forty-Ninth Embodiment 
       FIG. 236  comprises a perspective view, sectional views, a top view, and a side view of a one-hundred forty-ninth embodiment according to one aspect of the present invention, which is configured as a mobile telephone  55001 . The one-hundred forty-ninth embodiment has much in common with the one-hundred forty-fifth embodiment in  FIG. 231 ; therefore, common parts are identified by the same reference numerals, and no overlapping description will be repeated unless necessary. The one-hundred forty-ninth embodiment in  FIG. 236  differs from the one-hundred forty-fifth embodiment in  FIG. 231  in the structure with which the top frame  8227  is fitted and in the arrangement of a front camera and an infrared proximity sensor. 
     Specifically, an elastic member  52065  which serves as a vibration-absorbing member is interposed between the top frame  8227  and each of the right frame  8201   c , the left frame  8201   e , and the back plate  8201   b . This makes it difficult for the vibration of the top frame  8227  to conduct to the latter three. On the other hand, the top frame  8227  makes direct contact with the front plate  8201   a , so that the vibration of the top frame  8227  conducts to a top part of the front plate  8201   a . This design has two meanings. For one thing, as will be described later, the vibration of a ridge part between the front plate  8201   a  and the top frame  8227  can be conducted to the ear cartilage efficiently. For another thing, without the provision of a talk receiver relying on air conduction, such as a speaker, a top part of the front plate  8201   a  over a comparatively large area vibrates to generate air-conduction sound with a level required in common mobile telephones. 
     In the one-hundred forty-ninth embodiment, a piezoelectric bimorph element  52025  as a vibration source is a compact, thin one as in the one-hundred forty-fifth embodiment in  FIG. 231 , and is affixed directly to the inner face of the top frame  8227 . The vibration direction is perpendicular to the top face. With this configuration, in the one-hundred forty-ninth embodiment, a front camera  55017  and an infrared proximity sensor (an infrared light-emitter  55020  and an infrared proximity sensor  55021 ) are arranged at the middle of a top part of the mobile telephone  55001 . 
     A perspective view in  FIG. 236(A)  shows the above structure, and there it is seen that the top frame  8227  makes direct contact with the front plate  8201   a . Thus, the vibration of the top frame  8227  conducts to a top part of the front plate  8201   a . At the middle of the top part of the front plate  8201   a , the front camera  55017  is arranged which can shoot the operator viewing the large-screen display unit  8205  during a videophone session and which can be used to shoot the operator himself. With the front camera  55017  arranged at the middle of a top part of the front plate  8201   a  in this way, a user can shoot his own face from right in front. This arrangement of the front camera  55017  is made possible by the structure where a space is secured inside a top part of the mobile telephone  55001  by omitting a speaker as is arranged in an common mobile telephone and in addition by affixing, as a vibration source, a compact, thin piezoelectric bimorph element  52025  directly to the inner face of the top frame  8227 . 
     Also arranged at the middle of a top part of the front plate  8201   a  is a proximity sensor unit comprising the infrared light-emitter  55020  and the infrared proximity sensor  55021 . The aim is to detect the mobile telephone  55001  being put on the ear. With a proximity sensor unit arranged at the middle of the top part of the front plate  8201   a  in this way, irrespective of whether a right corner part  8224  is put on the cartilage of the right ear or a left corner part  8226  is put on the left ear, the contact can reliably be detected. On detecting the contact, it is possible, for example, to put out the backlight of the large-screen display unit  8205  and turn off the function of the touch panel. This arrangement of the proximity sensor unit too is made possible by the structure where a space is secured inside a top part of the mobile telephone  55001  by omitting a speaker as is arranged in an common mobile telephone and in addition by affixing, as a vibration source, a compact, thin piezoelectric bimorph element  52025  directly to the inner face of the top frame  8227 . 
     As will be clear from  FIG. 236(B) , which is a sectional view along B 1 -B 1  in  FIG. 236(A) , the compact piezoelectric bimorph element  52025  is affixed directly to the inner face of the top frame  8227 . Moreover, as indicated by broken lines, the front camera  55017  is arranged in the space secured by omitting a speaker as is arranged in an common mobile telephone and in addition by affixing a compact, thin piezoelectric bimorph element  52025  directly to the inner face of the top frame  8227 . The proximity sensor unit too is arranged in the middle space secured as described above, but to avoid complication, it is omitted from illustration. The vibration direction of the piezoelectric bimorph element  52025  is, as indicated by arrows  52025   a , perpendicular to the top face of the mobile telephone  55001 . 
     In  FIG. 236(C) , which is a top view, it is seen that the top frame  8227  and the front plate  8201   a  make direct contact with each other with no elastic member  52065  interposed. Also in  FIG. 236(D) , which is a sectional view along line B 2 -B 2  of  FIG. 236(A) or 236(B) , it is seen that the top frame  8227  and the front plate  8201   a  make direct contact with each other, and that the front camera  55017  is arranged in the space secured at the middle of a top part inside the mobile telephone  55001 . Also in  FIG. 236(E) , which is a left side view of  FIG. 236(A) , it is seen that a left corner part  8226  of the top frame  8227  and the front plate  8201   a  make direct contact with each other. 
     In the one-hundred forty-ninth embodiment, owing to the configuration described above, the vibration of the piezoelectric bimorph element  52025  perpendicular to the top face of the mobile telephone  55001  conducts to the entire top frame  8227 . Thus, as described in connection with the previous embodiments, with the right corner part  8224  put near the tragus of the right ear cartilage, or with the left corner part  8226  put near the tragus of the left ear cartilage, cartilage conduction can be obtained comfortably and efficiently in a way that fits the shape of the ear. A ridge part in a top front part of the mobile telephone  55001  between the front plate  8201   a  and the upper frame  8227  vibrates vigorously; thus, even when the mobile telephone  55001  is held such that a middle part of a top part of the mobile telephone  55001  is located in front of the external auditory meatus as with conventional mobile telephones, satisfactory cartilage conduction is obtained from the ridge part to the auricle. Moreover, also the air-conduction sound resulting from the vibration of the top part of the front plate  8201   a  enters the external auditory meatus. This air-conduction sound has a sound volume that meets a speaker standard for common mobile telephones. Even when the ridge part in the top front part of the mobile telephone  55001  is put on the auricle, by using it in a manner as will be described later, it is possible to produce a closed external auditory meatus effect. 
     The touch panel function of the large-screen display unit  8205  in the one-hundred forty-ninth embodiment can be exploited to achieve volume control by GUI. Specifically, a touch panel operation can invoke a volume adjustment mode, in which the sound volume can be adjusted through the touching of volume-up and -down operation parts that are displayed. By such volume adjustment performed through touch panel operation, the sound volume can be raised such that the air-conduction sound generated from the front plate  8201   a  has a level that meets a measurement standard for an ordinary speaker. On the other hand, when the mobile telephone  55001  of the one-hundred forty-ninth embodiment is used by exploiting cartilage conduction, the sound volume can be lowered such that the generated air-conduction sound has a level lower than a measurement standard for an ordinary speaker. Thus, the mobile telephone  55001  of the one-hundred forty-ninth embodiment allows volume adjustment covering two ranges as described above. 
     More specifically, through volume adjustment operation as described above, the mobile telephone  55001  can adjust the intensity of the vibration of the piezoelectric bimorph element  52025  for cartilage conduction at least between a first intensity (strong vibration) and a second intensity (weak vibration). Moreover, with the vibration that conducts from the top frame  8227 , to which the piezoelectric bimorph element  52025  is affixed, to the front plate  8201   a , air-conduction sound whose volume changes with the intensity of the vibration of the piezoelectric bimorph element  52025  is generated from a top part of the front plate  8201   a . The above-mentioned first intensity of vibration is an intensity sufficient to generate, from the top part of the front plate  8201   a , air-conduction sound with a volume that is necessary in a measurement method conforming to a standard for common mobile telephones (a measurement method in which the intensity of air-conduction sound collected by a predetermined microphone at a predetermined distance from the part of a mobile telephone at which it is put on the ear, the measurement target typically being air-conduction sound at a predetermined distance from a speaker). On the other hand, the above-mentioned second intensity of vibration is an intensity insufficient to generate, from the top part of the front plate  8201   a , air-conduction sound with the volume that is necessary in the measurement method conforming to the standard for common mobile telephones, and is such that the sound pressure inside the external auditory meatus as measured at a depth of 1 cm from the entrance of the external auditory meatus with the top part of the mobile telephone  55001  in contact with the ear cartilage is higher than the sound pressure inside the external auditory meatus as measured likewise at a depth of 1 cm from the entrance of the external auditory meatus with the top part of the mobile telephone out of contact with but close to the entrance of the external auditory meatus with the vibration at the first intensity. This results from the effect of cartilage conduction. 
       FIG. 237  shows a method for using the one-hundred forty-ninth embodiment in  FIG. 236  for cartilage conduction, comprising side views of the right ear and top views of the head, all being schematic. In  FIG. 237(A) , as in other embodiments, a right corner part  8224  is put on the ear cartilage near the tragus  32  of the right ear  28 . In this method of reception, the corner part of the mobile telephone  55001  fits the shape of the right ear  28 . In this method of use, in a noisy environment, a user&#39;s natural motion to increase the pressure on the right ear  28  for better reception causes the tragus  32  to close the external auditory meatus, and owing to this closed external auditory meatus effect, target sound is augmented while outside sound is blocked. 
     On the other hand,  FIG. 237(B)  shows another method of use in which the mobile telephone  55001  is put on the right ear  28  with the face pointing frontward, wherein the mobile telephone  55001  is held transversely, roughly horizontally, such that a middle part of a ridge part of a top front part of the mobile telephone  55001  is put on a base part of the tragus  32  (a front edge part of the entrance of the external auditory meatus) from in front of the right ear  28 . In the method of use shown in  FIG. 237(B) , when the mobile telephone  55001  is put on the right ear  28  with the user in a forward inclined posture as often seen during an ordinary call, the mobile telephone  55001  held in the right hand has a natural inclination, making its use comfortable to the user. When the method of use in  FIG. 237(B)  is adopted, and a middle part of the mobile telephone  55001  is put on the right ear  28 , the mobile telephone  55001  does not cover the right ear  28 , and thus the tragus is not flattened. Thus, the middle part of the ridge part can be put on the cartilage in a front edge part of the entrance of the external auditory meatus (the base of the tragus  32 ). The display screen is then prevented from being soiled by contact with the auricle or cheek. This position of the mobile telephone  55001   a  is indicated by a dash-and-dot line in  FIG. 237(B) . In this method of use, in an environment with loud noise, the mobile telephone  55001  can be pressed slightly further rearward. The tragus  32  is then pressed and bent to close the external auditory meatus, producing a closed external auditory meatus effect. This position of the mobile telephone  55001   b  is indicated by a broken line in  FIG. 237(B) . A closed external auditory meatus effect can be produced without flattening the auricle. 
     On the other hand,  FIG. 237(C)  is a schematic diagram of the head as seen from above, showing a state corresponding to the position of the mobile telephone  55001   a  in  FIG. 237(B) . It is seen that the mobile telephone  55001   a  is put on the base of the tragus  32 .  FIG. 237(D)  shows a state corresponding to the position of the mobile telephone  55001   b  in  FIG. 237(B) . It is seen that the mobile telephone  55001   a  is pressed further rearward so that the tragus  32  bends rearward to close the external auditory meatus. As described above, according to the one-hundred forty-ninth embodiment, it is possible to perform cartilage conduction reception, and cartilage conduction reception accompanied by a closed external auditory meatus effect, with a mobile telephone held in in a manner closer to a conventional manner (but more comfortable in that the auricle is not covered and is not flattened). 
       FIG. 238  comprises perspective views of a mobile telephone, showing examples of explanations of methods of its use in the one-hundred forty-ninth embodiment shown in  FIG. 237 .  FIG. 238(A)  shows an explanation of right-ear reception using a corner part shown in  FIG. 237(A) , which is similar to that in  FIG. 150(C)  showing the ninety-seventh embodiment. Specifically, on the large-screen display unit  8205 , the right corner part  8224  is graphically indicated, and a guidance message is displayed saying “To hear, put this corner on the right earhole”. The display may be accompanied by similar guidance sounded from a videophone speaker. Likewise,  FIG. 238(B)  shows an explanation of left-ear reception using a corner part. On the large-screen display unit  8205 , the left corner part  8226  is indicated graphically, and a guidance message is displayed saying “To hear, put this corner on the right earhole”. As with the guidance for the right ear, the display here may be accompanied by similar sounded guidance. As with switching between  FIGS. 150(C)  and (D) in the ninety-seventh embodiment, switching between  FIGS. 237(A)  and (B) is performed automatically by detecting the inclination of the mobile telephone. 
     On the other hand,  FIG. 238(C)  shows an explanation of reception using the middle part of the ridge of the top part shown in  FIG. 237(B) . Specifically, on the large-screen display unit  8205 , the middle of the top part of the mobile telephone is indicated graphically, and a guidance message is displayed saying “To hear, put the top end in front of the earhole from ahead”. In addition, a message is displayed saying “You can hear well without covering the ear” to mention the distinctive feature of the present invention. As in  FIGS. 238(A)  and (B), the display may be accompanied by similar guidance sounded from a videophone speaker. 
       FIG. 238(D)  shows an explanation that is called up automatically in an environment with loud noise and is displayed alternately with the one in  FIG. 238(C)  at time intervals of about three seconds. The explanation contains a graphical indication of the direction in which to press further, and a message saying “In noisy surroundings, press the phone further back to close the earhole so that you can hear louder with less outside sound”. 
     In cases where, as in  FIG. 238 , methods of use are indicated graphically on the large-screen display unit  8205 , a better understanding will be achieved by displaying not only explanations in text but also schematic diagrams showing methods of use as in  FIG. 237 . 
     One-Hundred Fiftieth Embodiment 
       FIG. 239  comprises a perspective view, sectional views, and a top view of a one-hundred fiftieth embodiment according to one aspect of the present invention, which is configured as a mobile telephone  56001 . The one-hundred fiftieth embodiment has much in common with the one-hundred forty-ninth embodiment in  FIG. 236 ; therefore, common parts are identified by the same reference numerals, and no overlapping description will be repeated unless necessary. The one-hundred fiftieth embodiment in  FIG. 239  differs from the one-hundred forty-ninth embodiment in  FIG. 236  chiefly in casing structure. 
     Specifically, the casing of the mobile telephone  56001  is composed of a box-shaped case  56227 , which is open at the front, and a front plate  56201 , which fits in the case  56227  to cover its front. As in the one-hundred forty-ninth embodiment, a piezoelectric bimorph element  52025  as a vibration source is affixed to the inner side of the top face of the case  56227 . Here, the case  56227  makes direct contact with the front plate  56201 , and thus the vibration of the top face of the case  56227  conducts to a top part of the front plate  56201 . As a result, as in the one-hundred forty-ninth embodiment, the vibration of a ridge part between the front plate  56201  and a top part of the case  56227  conducts to the ear cartilage efficiently. Moreover, even without the provision of a talk receiver relying on air conduction, such as a speaker, the top part of the front plate  56201  over a comparatively large area vibrates to generate air-conduction sound with a level required in common mobile telephones. 
     Also in the one-hundred fiftieth embodiment, as in the one-hundred forty-ninth embodiment, the piezoelectric bimorph element  52025  as a vibration source is a compact, thin one, and is, as mentioned above, affixed directly to the inner side of the top face of the case  56227 . Its vibration direction is, as in the one-hundred forty-ninth embodiment, perpendicular to the top face. With this configuration, also in the one-hundred fiftieth embodiment, a front camera  56017  and a proximity sensor unit  56019  can be arranged at the middle of a top part of the mobile telephone  56001 . 
     A perspective view in  FIG. 239(A)  shows the structure described above, and there it is seen that the case  56227  makes direct contact with the front plate  56201 . Thus, the vibration of the top part of the case  56227  conducts to the top part of the front plate  56201 . At the middle of the top part of the front plate  56201 , the proximity sensor unit  56019  is arranged, which comprises an infrared light-emitter  56020  and an infrared proximity sensor  56021  that are integrated into a unit. With the proximity sensor unit  56019  arranged at the middle of the top part of the front plate  56201  in this way, as in the one-hundred forty-ninth embodiment, irrespective of whether the right corner part  8224  is put on the cartilage of the right ear or the left corner part  8226  is put on the left ear, the contact is detected reliably. This arrangement of the proximity sensor unit  56019  is made possible by the structure where a space is secured inside a top part of the mobile telephone  56001  by omitting a speaker as is arranged in an common mobile telephone and in addition by affixing, as a vibration source, a compact, thin piezoelectric bimorph element  52025  directly to the inner side of the top face of the case  56227 . 
     Near the middle of the top part of the front plate  56201 , the front camera  56017  is arranged. Thus, roughly as in the one-hundred forty-ninth embodiment, a user can shoot his own face from right in front. This arrangement of the front camera  56017 , too, is made possible by the structure where a space is secured inside a top part of the mobile telephone  56001  by omitting a speaker as is arranged in an common mobile telephone and in addition by affixing, as a vibration source, a compact, thin piezoelectric bimorph element  52025  directly to the inner side of the top face of the case  56227 . 
     As will be clear from  FIG. 239(B) , which is a sectional view along line B 1 -B 1  in  FIG. 239(A) , as in the one-hundred forty-ninth embodiment, the compact piezoelectric bimorph element  52025  is affixed directly to the inner side of the top face of the case  56227 . As indicated by a broken line, the proximity sensor unit  56019  is arranged in the middle space secured by omitting a speaker as is arranged in an common mobile telephone and in addition by affixing a compact, thin piezoelectric bimorph element  52025  directly to the inner side of the top face of the case  56227 . As for the front camera  56017  arranged near the middle, to avoid complication, it is omitted from illustration. The vibration direction of the piezoelectric bimorph element  52025  is, as indicated by arrows  52025   a , perpendicular to the top face of the mobile telephone  56001  as in the one-hundred forty-ninth embodiment. 
     In  FIG. 239(C) , which is a top view, it is seen that the front plate  56201  makes direct contact with, and fits in, the front of the case  56227 . Also in  FIG. 239(D) , which is a sectional view along line B 2 -B 2  in  FIGS. 239(A) to 239(C) , it is seen that the front plate  56201  makes direct contact with the front of the case  56227 , and that the proximity sensor unit  56019  is arranged in the middle space secured in the top part inside the mobile telephone  56001 . 
     In the one-hundred fiftieth embodiment configured as described above, as in the one-hundred forty-ninth embodiment, the vibration of the piezoelectric bimorph element  52025  perpendicular to the top face of the mobile telephone  56001  conducts to the entire top frame  56227 . Thus, as described in connection with the previous embodiments, with the right corner part  8224  put near the tragus of the right ear cartilage, or with the left corner part  8226  put near the tragus of the left ear cartilage, cartilage conduction can be obtained comfortably and efficiently in a way that fits the shape of the ear. A ridge part in a top front part of the mobile telephone  56001  between the front plate  56201  and the top face of the case  56227  vibrates vigorously. Thus, even when the mobile telephone  56001  is held such that a middle part of a top part of the mobile telephone  56001  is located in front of the external auditory meatus as with conventional mobile telephones, satisfactory cartilage conduction is obtained from the ridge part to the auricle. Moreover, also the air-conduction sound resulting from the vibration of the top part of the front plate  56201  enters the external auditory meatus. As in the one-hundred forty-ninth embodiment, this air-conduction sound has a sound volume that meets a speaker standard for common mobile telephones. Even when the ridge part in the top front part of the mobile telephone  56001  is put on the auricle, by using it in the manner described with reference to  FIG. 237  showing the one-hundred forty-ninth embodiment, it is possible to produce a closed external auditory meatus effect. Also in the one-hundred fiftieth embodiment, explanations of methods of use as shown in  FIG. 238  can be displayed. 
     The above-described features of the present invention are not limited to the embodiment specifically described above, but can be implemented in any other embodiment so long as they provide their benefits. Also, features from different embodiments can be implemented in intermingled manners. For example, the arrangement of the front camera and the proximity sensor unit in the one-hundred forty-ninth and one-hundred fiftieth embodiments is not limited to those specific embodiments, but may be adopted in any other embodiment. As to how to make good use of the space secured by omitting an ordinary speaker or other vibration source from a front-face part of a mobile telephone, various layouts can be adopted for components, like a front camera and a proximity sensor unit, that benefit from being arranged at the middle. 
     As for explanations of methods of use like those shown in  FIGS. 238(C)  and (D) and diagrammatic explanations like those shown in  FIG. 237 , these can be presented not only on the display surface of products themselves as in the embodiment but also in instruction manuals attached to products, in catalogs of products, or via various advertising media or the like including electronic media available on the Internet or the like. 
     Methods of use like those shown in  FIG. 237(B)  to (D) and  FIGS. 238(C)  and (D) are not limited to configurations where, as in the one-hundred forty-ninth and one-hundred fiftieth embodiments, comparatively loud air-conduction sound is generated as well, but are useful also in mobile telephones configured to suppress generation of air-conduction sound as in the one-hundred fifty-fifth embodiment in  FIG. 231 . 
     One-Hundred Fifty-First Embodiment 
       FIG. 240  is a block diagram related to a one-hundred fifty-first embodiment according to one aspect of the present invention, which is configured as a mobile telephone  57001 . The one-hundred fifty-first embodiment in  FIG. 240  has much in common with the fourth embodiment shown in  FIG. 8 ; accordingly, common parts are identified by common reference numerals, and overlapping descriptions will not be repeated unless necessary. The description that follows presupposes the following features. In the one-hundred fifty-first embodiment, as in the fourth embodiment, a proximity sensor unit  56019  comprising infrared light emitting units  19  and  20  and an infrared light proximity sensor  21  detects the mobile telephone  57001  being put on an ear. Moreover, in the one-hundred fifty-first embodiment, as in the fourth embodiment, the pressure sensor  242  detects the pressing force of the mobile telephone  57001  having increased to such a degree as to produce a closed external auditory meatus effect. Moreover, in the one-hundred fifty-first embodiment, an operation unit  9  can be operated to adjust sound volume and switch modes. 
     In the one-hundred fifty-first embodiment in  FIG. 240 , as in the one-hundred forty-ninth embodiment shown in  FIG. 236  or the one-hundred fiftieth embodiment shown in  FIG. 239 , there is provided a vibration source such as a piezoelectric bimorph element for cartilage conduction, and, for cartilage conduction, its vibration is conducted to a top frame including both corner parts and also to a front plate. This results in a configuration where, without the provision of a talk-receiving unit relying on air conduction, such as a speaker, a top part of the front plate over a comparatively large area vibrates to generate air-conduction sound with a level required in common mobile telephones. Thus, the following description of the one-hundred fifty-first embodiment presupposes the configuration in  FIG. 236  related to the one-hundred forty-ninth embodiment or the configuration in  FIG. 239  related to the one-hundred fiftieth embodiment. 
     The basic configuration of the one-hundred fifty-first embodiment is as described above. A feature of the one-hundred fifty-first embodiment is that cartilage conduction is exploited with consideration given to the conventionally known relationship between air conduction and bone conduction in terms of vibration power in particular. As mentioned above, in the one-hundred fifty-first embodiment, a configuration is adopted where a vibration source for cartilage conduction is used doubly for generation of air-conduction sound. And, through sound volume adjustment or mode switching on the operation unit  9 , it is possible to perform an air-conduction sound generation test with a common mobile telephone. In an air-conduction sound generation test with a common mobile telephone, a test microphone is placed near an upper part (where a speaker is usually arranged) of the mobile telephone in a non-contact manner, and it is tested whether or not the test microphone detects air-conduction sound of a predetermined level or more. In the one-hundred fifty-first embodiment, a configuration is adopted where, as described above, through sound volume adjustment on the operation unit  9 , the sound volume can be increased until air-conduction sound of a predetermined level is obtained at the test microphone. Or, through switching from a use mode to a test mode on the operation unit  9 , the sound volume is increased from that in the use mode so that a predetermined sound pressure is obtained at the test microphone. 
     In a common mobile telephone provided with a speaker, sound is heard as a result of air-conduction sound from the speaker reaching the eardrum, and thus no inconvenience arises between testing and use. However, the sound heard in the use state of the one-hundred fifty-first embodiment results chiefly from cartilage conduction. In other words, in the use state of the one-hundred fifty-first embodiment, when an upper part of the mobile telephone  57001  is put in contact with the ear, cartilage conduction occurs, and this results in a significant increase in the sound pressure near the human eardrum compared with the sound pressure detected by the test microphone in a non-contact manner in the test state. That sound pressure is excessive compared with the sound volume set assuming comfortable cartilage conduction, and can cause the user to surprise or feel pain. Moreover, when the pressure with which the mobile telephone  57001  is put in contact with the ear is increased to bring about an occluded state of the external auditory meatus, the sound pressure further increases, possibly making the vibration power set in the test state more excessive. 
     Configured with consideration given to the foregoing, the one-hundred fifty-first embodiment is configured such that the vibration source for cartilage conduction is used doubly for generation of air-conduction sound and in addition that the sound volume is adjustable so that the sound pressure inside the external auditory meatus in a state where cartilage conduction is occurring is suppressed so as not to be excessive. The direct aim of the suppression is to suppress the maximum value of the sound pressure inside the external auditory meatus in a state where cartilage conduction is occurring such that it is equal to or less than a predetermined level; in practice, it is suppressed such that the sound pressure inside the external auditory meatus due to air-conduction sound alone in a non-contact state when hearing achieved by cartilage conduction is presupposed is equal to or less than a predetermined level. That is, the sound pressure in a non-contact state is suppressed with consideration given to the average increase in the sound pressure in a contact state. Moreover, as to cartilage conduction in an occluded state of the external auditory meatus and as to cartilage conduction in an occluded state of the external auditory meatus with a sound pressure further increased from that state, the suppression is performed on different criteria respectively. The necessity for the suppression and the type of the suppression are selected according to the presence/absence of a test setting, the sound volume that is set, detection by the proximity sensor unit  56019 , and detection by the pressure sensor  242 . 
     Based on  FIG. 240 , the one-hundred fifty-first embodiment will be described specifically. A cartilage conduction vibration unit  57228  that doubles as a vibration source for generating air-conduction sound is driven by a drive signal from a phase adjustment mixer unit  236 . Between the phase adjustment mixer unit  236  and the cartilage conduction vibration unit  57228 , a vibration limiter unit  57040  is provided. The vibration limiter unit  57040  serves to suppress vibration by limiting the drive signal when the sound volume setting is left such that the sound pressure on occurrence of cartilage conduction is excessive. 
     The vibration limiter unit  57040  includes an upper limit checker  57036 , which automatically checks whether or not such a sound volume setting has been made as to cause an excessive sound pressure on occurrence of cartilage conduction. If so, a variable attenuator  57037  is operated to automatically suppress the vibration of the cartilage conduction vibration unit  57228 . The mobile telephone  57001  of the one-hundred fifty-first embodiment presupposes use by cartilage conduction, and thus the state where the upper limit checker  57036  and the variable attenuator  57037  operate automatically as described above is assumed to be the standard state. Here, the check level of the upper limit checker  57036  is set lower than the level at which the pressure sensor  242  detects the pressing force of the mobile telephone  57001  having increased to such a degree as to produce a closed external auditory meatus effect. 
     In the one-hundred fifty-first embodiment, an air-conduction sound test mode can be set so that, when the test mode is set, through operation on the operation unit  9 , the sound volume can be set up to the maximum sound volume (the sound volume that may cause an excessive sound pressure inside the external auditory meatus on occurrence of cartilage conduction). A configuration is possible where such sound volume setting can be performed as part of volume setting operation as described above; a configuration is also possible where switching to the test mode automatically brings about switching to the maximum sound volume. When the test mode is set, the automatic function of the upper limit checker  57036  and the variable attenuator  57037  is turned off. On the other hand, when the test mode is canceled, the automatic function of the upper limit checker  57036  and the variable attenuator  57037  is restored. 
     In the one-hundred fifty-first embodiment, even when the test mode described above is left uncanceled, when the proximity sensor unit  56019  detects the mobile telephone  57001  being put on the ear, so long as the mobile telephone  57001  is put on the ear, the above-mentioned automatic function of the upper limit checker  57036  and the variable attenuator  57037  is restored. Accordingly, even if, when the test mode is set, such a sound volume setting has been made on the operation unit  9  as to cause an excessive sound pressure inside the external auditory meatus with consideration given precautionally to the increase in the sound pressure due to cartilage conduction, when the mobile telephone  57001  is put on the ear, the upper limit checker  57036  and the variable attenuator  57037  automatically suppress an excessive output. 
     The vibration limiter unit  57040  further includes a variable equalizer  57038 . The increase in the sound pressure inside the external auditory meatus due to cartilage conduction has wavelength dependence as shown in  FIG. 79 . The tendency is that cartilage conduction causes a larger increase in sound pressure in a low frequency range than in a high frequency range. The variable equalizer  57038  in a standard state provides equalization suitable for cartilage conduction but, by manually setting the air-conduction sound test mode, can be switched to equalization suitable for air-conduction sound. When the proximity sensor unit  56019  detects the mobile telephone  57001  being put on the ear without the test mode canceled and thus with testing-oriented equalization suitable for air-conduction sound still in effect, the equalization is automatically changed to that in the standard use state where the sound pressure is suppressed more in a low frequency range than in a high frequency range. Furthermore, the variable equalizer  57038  is automatically switched such that the sound pressure in a high frequency range and that in a low frequency range are suppressed with different frequency characteristics between when the proximity sensor unit  56019  detects the mobile telephone  57001  being put on the ear in an open state of the external auditory meatus and when the pressure sensor  242  detects the pressing force of the mobile telephone  57001  having increased to such a degree to produce a closed external auditory meatus effect. 
     The one-hundred fifty-first embodiment has thus far been described from the perspective of the relationship between air conduction and cartilage conduction, and will now be described from the perspective of the relationship between bone conduction and cartilage conduction. As is well known, the vibration power needed to cause the cranium to vibrate from outside the human body to make sound heard by bone conduction is extremely high. In comparison, the vibration power required in the cartilage conduction vibration source in the one-hundred fifty-first embodiment is lower by orders of magnitude. As one example, suppose, in the one-hundred fifty-first embodiment, the maximum vibration power is set assuming cartilage conduction in an open state of the external auditory meatus and the cartilage conduction unit (the right or left side corner part  8224  or  8226  in  FIG. 236  showing the one-hundred forty-ninth embodiment which the one-hundred fiftieth embodiment supplementarily refers to) is put, for discussion&#39;s sake, on a mastoid process which is common as a contact location for bone conduction. This operation is performed with attention paid so as to produce no contact with an ear cartilage. Here, even if the cartilage conduction unit is pressed with such a strong contact force as is required in ordinary bone conduction, it is not possible to obtain a sound volume sufficient to make conversation heard. This indicates that the cartilage conduction unit in the one-hundred fifty-first embodiment does not function as a bone conduction unit. 
     In a case where the maximum vibration power is set assuming cartilage conduction in a closed state of the external auditory meatus, a still lower vibration power is required of the cartilage conduction vibration source. With such a vibration power, even when the cartilage conduction unit is pressed against the mastoid process in an attempt to obtain cartilage conduction, it is still more difficult to hear sound. 
     As described above, the cartilage conduction unit in the mobile telephone  57001  configured based on cartilage conduction is configured differently from, and involves a clearly different vibration power from, a bone conduction contact unit in bone conduction. 
       FIG. 241  is a flow chart of the operation of a control unit  57039  in the one-hundred fifty-first embodiment in  FIG. 240 . The flow in  FIG. 241  is aimed at illustrating control for suppressing generation of an excessive sound pressure inside the external auditory meatus, and focuses on relevant functions, showing operation in an extracted manner. Accordingly, there are other operations of the control unit  57039  that are not shown in the flow in  FIG. 241 , such as the functions of a common mobile telephone. The flow in  FIG. 241  starts when the main power to the mobile telephone  57001  is turned on, and at step S 972 , the variable attenuator  57037  is turned on in the standard state. Subsequently, likewise in the standard state, at step S 974 , the upper limit checker  57036  is turned on with the standard check level (the level that is excessive in cartilage conduction in an open state of the external auditory meatus), and at step S 976 , the variable equalizer  57038  is set in a state suitable for cartilage conduction in an open state of the external auditory meatus, the flow then proceeding to step S 978 . 
     At step S 978 , it is checked whether or not the pressure sensor  242  detects a closed state of the external auditory meatus, and if a closed state of the external auditory meatus is detected, the flow proceeds to step S 980 , where the upper check level is shifted down to be set at a level that is excessive in cartilage conduction in a closed state of the external auditory meatus. Then, at step S 982 , the variable equalizer  57038  is set in a state suitable for cartilage conduction in a closed state of the external auditory meatus, the flow then proceeding to step S 984 . On the other hand, if, at step S 978 , the pressure sensor  242  does not detect a closed state of the external auditory meatus, the flow proceeds to step S 986 , where the upper check limit is set at the normal level, and then at step S 988 , the variable equalizer  57038  is set in a state suitable for cartilage conduction in an open state of the external auditory meatus, the flow then proceeding to step S 984 . At any of steps S 980 , S 982 , S 986 , and S 988 , if it is reached in a state requiring no change, nothing is performed. 
     At step S 984 , the upper limit checker  57036  checks whether or not the output exceeds the upper limit. If the upper limit is exceeded, the flow proceeds to step S 990 , where the variable attenuator  57037  attenuates the output down to the upper limit, the flow then proceeding to step S 992 . On the other hand, if, at step S 984 , the output is not detected exceeding the upper limit, the flow proceeds to step S 994 , where, without any attenuation by the variable attenuator  57037 , the cartilage conduction vibration unit  57228  is driven at the original output, the flow then proceeding to step S 992 . 
     At step S 992 , it is checked whether or not the test mode has been set on the operation unit  9 . Here, also if a high sound volume equal to or higher than a predetermined level has been set on the operation unit  9 , it is regarded that the test mode has been set. If, at step S 992 , the test mode is detected having been set, the flow proceeds to step S 996 , where the proximity sensor unit  56019  checks whether or not the mobile telephone  57001  is put in contact with the ear. If no contact with the ear is detected, it is regarded that the test state is in effect, and the flow proceeds to step S 998 , where the upper limit checker  57036  is turned off. Subsequently, at step S 1000 , the variable attenuator  57037  is turned off, and, at step S 1002 , the variable equalizer  57038  is set in a state suitable for generation of air-conduction sound, the flow then returning to step S 992 . Thereafter, unless cancellation of the test mode is detected at step S 992  or the proximity sensor unit  56019  detects contact with the ear at step S 996 , steps S 992  through S 1002  are repeated to continue the test state. 
     On the other hand, if, at step S 992 , cancellation of the test mode is detected or if, at step S 996 , contact with the ear is detected, the flow proceeds to step S 1004 , where it is checked whether or not the main power has been turned off. If, at step S 1004 , the main power is not detected having been turned off, the flow returns to step S 972 , and thereafter, unless the main power is detected having been turned off at step S 1004 , steps S 972  through S 1004  are repeated to cope with various changes of state. 
     When the flow exits from the loop of steps S 992  through S 1002  for executing the test mode and returns via step S 1004  to step S 972 , then, at steps S 972  through S 976 , the operation of the vibration limiter unit  57040  is restored. At this time, if step S 1004  is reached as a result of cancellation of the test mode being detected at step S 992 , the flow returns to the normal mode. On the other hand, if step S 1004  is reached, without cancellation of the test mode, as a result of contact with the ear at step S 996 , the flow reaches step S 992  and enters the test mode. However, at this time, if continued contact with the ear is detected at step S 996 , the flow once again returns to step S 972 , and thus the function of the vibration limiter unit  57040  is maintained. On the other hand, if, at step S 996 , contact with the ear is detected having ceased, the flow proceeds to step S 998 , and thus the test mode is restored. 
     One-Hundred Fifty-Second Embodiment 
       FIG. 242  comprises a perspective view and sectional views related to a one-hundred fifty-second embodiment according to one aspect of the present invention, which is configured as a mobile telephone  58001 . The one-hundred fifty-second embodiment is configured as a liquid crystal display  58205  which has a touch panel function over a large part of the front face; based on this configuration, a top side and both corner parts of a top part of the mobile telephone  58001  serve as a cartilage conduction unit, and generation of air-conduction sound from the surface of the liquid crystal display  58205  is suppressed. For other details, those described in connection with other embodiments can be adopted, and accordingly, for simplicity&#39;s sake, their illustration and description will be omitted. 
       FIG. 242A  is a perspective view of the mobile telephone  58001  of the one-hundred fifty-second embodiment as seen from in front, and a large part of the front face of the mobile telephone  58001  is a liquid crystal display  58205  having a touch panel function. In particular, a top part of it has so large an area as to approach the frame parts on the top and side faces.  FIG. 242B  is a sectional view showing the mobile telephone  58001  as cut along a plane perpendicular to the front and side faces on the sectional plane B 1 -B 1  in  FIG. 242A . As will be described later, a piezoelectric bimorph element  58025  is affixed to the reverse side of the center of the top frame, and is therefore not located on the sectional plane; instead, a perspective positional relationship as seen from above the mobile telephone  58001  is indicated by a broken line  58025 . 
     Between the liquid crystal display  58205  and side frame parts of the casing of the mobile telephone  58001 , an elastic body  58065  serving as a vibration-absorbing material is interposed, so that the vibration of the top frame to which the piezoelectric bimorph element  58025  is affixed is less likely to conduct to the liquid crystal display  58205 . Furthermore, in a top part of the reverse side of the liquid crystal display  58205 , a vibration-suppressing extension  58205   a  is integrally provided, and to this vibration-suppressing extension  58205   a , a weight  58048  is fixed so as not to touch another component inside the mobile telephone  58001 . Thus, what little vibration that conducts to the liquid crystal display  58205  is further suppressed. The weight  58048  has only to be arranged so as not to touch, in rigid terms, another component inside the mobile telephone  58001 ; it may be coupled to another component via a flexible material, such as a flexible circuit board, that is unlikely to conduct vibration. 
     In  FIG. 242C , which is a sectional view along B 2 -B 2  shown in  FIG. 242A , it is seen that the piezoelectric bimorph element  58025  is affixed to the reverse side of the top frame of the casing of the mobile telephone  58001 . Moreover, also between the liquid crystal display  58205  and a casing frame part and a casing front-face lower part of the mobile telephone  58001 , the elastic body  58065  serving as a vibration-absorbing material is interposed, so that the vibration of the top frame to which the piezoelectric bimorph element  58025  is affixed is unlikely to conduct to the liquid crystal display  58205 . Thus, the elastic body  58065  is interposed all around the liquid crystal display  58205 , so that vibration from the frame part of the casing of the mobile telephone  58001  is unlikely to conduct to the liquid crystal display  58205 . 
     One-Hundred Fifty-Third Embodiment 
       FIG. 243  comprises a perspective view and sectional views related to a one-hundred fifty-third embodiment according to one aspect of the present invention, which is configured as a mobile telephone  59001 . The one-hundred fifty-third embodiment has much in common with the one-hundred fifty-second embodiment in  FIG. 242 ; accordingly, the same parts are identified by the same reference numerals, and no overlapping description will be repeated. 
     A first difference of the one-hundred fifty-third embodiment from the one-hundred fifty-second embodiment is that a piezoelectric bimorph element holder  59001   a  is provided at the center of the reverse side of the top frame of the mobile telephone  59001 , and that the piezoelectric bimorph element  58025  is held on the piezoelectric bimorph element holder  59001   a  such that the vibration direction of the former is perpendicular to the liquid crystal display  58205 . 
     A second difference of the one-hundred fifty-third embodiment from the one-hundred fifty-second embodiment is that, as a structure for suppressing the vibration of the liquid crystal display  58205 , a vibration-suppressing extension  58025   b  provided integrally in a top part of the reverse side of the liquid crystal display  58205  is connected to a weight part  59048 , such as a battery, inside the mobile telephone  59001 . Thus, what little vibration that conducts from the top frame to the liquid crystal display  58205  is further suppressed. 
     One-Hundred Fifty-Fourth Embodiment 
       FIG. 244  comprises a perspective view and sectional views related to a one-hundred fifty-fourth embodiment according to one aspect of the present invention, which is configured as a mobile telephone  60001 . The one-hundred fifty-fourth embodiment has much in common with the one-hundred fifty-second embodiment in  FIG. 242  or the one-hundred fifty-third embodiment in  FIG. 243 ; accordingly, the same parts are identified by the same reference numerals, and no overlapping description will be repeated. 
     A first difference of the one-hundred fifty-fourth embodiment from the one-hundred fifty-second or -third embodiment is that a piezoelectric bimorph element holder  60001   a  is provided at the center of the reverse side of the top frame of the mobile telephone  60001 , and that the piezoelectric bimorph element  60025  is held on the piezoelectric bimorph element holder  60001   a  such that the vibration direction of the former is inclined relative to both the liquid crystal display  58205  and the top frame of the mobile telephone  60001  (for example, at 45 degrees relative to both). 
     A second difference of the one-hundred fifty-fourth embodiment from the one-hundred fifty-second or -third embodiment is that, as a structure for suppressing the vibration of the liquid crystal display  58205 , a vibration-absorbing elastic body  60048  is held between a vibration-suppressing extension  58205   c  provided integrally with a top part of the reverse side of the liquid crystal display  58205  and the inside of the rear wall of the mobile telephone  60001 . Thus, what little vibration that conducts from the top frame to the liquid crystal display  58205  is further suppressed. 
     The combination of a structure for fitting the piezoelectric bimorph element ( 58025 ,  59025 ,  60025 ) to the rear side of the top frame and a structure for suppressing the vibration of the liquid crystal display  58205  in the one-hundred fifty-second to -fourth embodiments are not peculiar to these embodiments; features from different embodiments can be combined together freely. For example, it is possible to adopt a combination of the structure for fitting the piezoelectric bimorph element  58025  in the one-hundred fifty-second embodiment and the structure for suppressing the vibration of the piezoelectric bimorph element  58025  in the one-hundred fifty-third embodiment. 
     Furthermore, none of the features of the above-described embodiments of the present invention are limited to those embodiments; they may be adopted in any other embodiments so long as they provide their benefits. Moreover, features from different embodiments can be adopted in combination. For example, the proximity sensor unit  56019  in the one-hundred fifty-first embodiment may be arranged like the proximity sensor unit  56019  in  FIG. 239 . As the pressure sensor  242  used in the one-hundred fifty-first embodiment, as illustrated in  FIG. 9  in connection with the fourth embodiment, the cartilage conduction vibration source  225  comprising a piezoelectric bimorph element can be used doubly. Instead, a dedicated pressure sensor may be used, and it can be used doubly for detection of a pressing force. Furthermore, as to sound volume adjustment in the one-hundred fifty-first embodiment, a configuration may be adopted where it is achieved, as in the one-hundred forty-ninth embodiment in  FIG. 236 , by GUI or the like using the touch panel function of the liquid crystal display  58205 . 
     The one-hundred fifty-first embodiment is configured as a mobile telephone that allows hearing by cartilage conduction and that can also generate air-conduction sound with a level required in common mobile telephones. However, also with mobile telephones structured to suppress generation of air-conduction sound as in other embodiments, it is useful to apply to them the features of the one-hundred fifty-first embodiment which gives consideration to an excessive increase in sound pressure resulting from occurrence of cartilage conduction by contact or an excessive increase in sound pressure resulting from occurrence of a closed external auditory meatus effect. In particular, in mobile telephones structured so as to ideally suppress air-conduction sound, on occurrence of cartilage conduction, cartilage air-conduction sound contributes more than direct air-conduction sound (though depending on differences among individuals, a change from a non-contact state to a contact state is observed to cause, in the sound pressure inside the external auditory meatus, an increase of 30 dB at the maximum in terms of the average in speech region of 3000 Hz or less and an increase of 50 dB at the maximum at 500 Hz). Thus, with mobile telephones structured to allow air-conduction sound tests, it is useful to suppress the sound pressure inside the external auditory meatus such that it is not excessive in a state where cartilage conduction is occurring. 
     In a case where, in the one-hundred fifty-second to -fourth embodiments, the vibration of the liquid crystal display  58205  is not suppressed and air-conduction sound is generated as in the one-hundred forty-ninth to fifty-first embodiments, the elastic body  58065  is not provided between the casing part of the mobile telephone  58001  and the liquid crystal display  58205 , and also the vibration-suppressing structure via the vibration-suppressing extension  58205   a ,  58205   b , or  58205   c  is omitted. 
     One-Hundred Fifty-Fifth Embodiment 
       FIG. 245  comprises a perspective view and sectional views related to a one-hundred fifty-fifth embodiment according to one aspect of the present invention, which is configured as a mobile telephone  61001 . The one-hundred fifty-fifth embodiment has much in common with the one-hundred fifty-second embodiment in  FIG. 242 ; accordingly, the same parts are identified by the same reference numerals, and no overlapping description will be repeated. 
     The one-hundred fifty-fifth embodiment in  FIG. 245  differs from the one-hundred fifty-second embodiment in  FIG. 242  in the structure for suppressing air-conduction sound.  FIG. 245A  is a perspective view of the mobile telephone  61001  of the one-hundred fifty-fifth embodiment as seen from in front, and, as in the one-hundred fifty-second embodiment in  FIG. 242 , a large part of the front face of the mobile telephone  61001  is a liquid crystal display  58205  having a touch panel function. As is clearly shown in  FIG. 245A , the casing of the mobile telephone  61001  of the one-hundred fifty-fifth embodiment is configured such that a front plate  61201   a  and a rear plate  61201   b  (not appearing in  FIG. 245A ) hold between then an integral frame composed of a top frame  61227 , a right frame  61201   c , and the like. Here, between the front plate  61201   a  and the integral frame, an elastic packing ring  61065   a  serving as a vibration-absorbing material is interposed, and likewise, between the integral frame and the rear plate  61201   b , an elastic packing ring  61065   b  serving as a vibration-absorbing material is interposed. Thus, conduction of the vibration of a piezoelectric bimorph element  61025  affixed to the top frame  61227  to the front and rear plates  61201   a  and  61201   b  is alleviated, and as the top frame  61227  vibrates, both corner parts of the mobile telephone  61001  serve as satisfactory cartilage conduction units. 
       FIG. 245B  is a sectional view of the mobile telephone  61001  as cut along a plane perpendicular to the front and side faces on the sectional plane B 1 -B 1  in  FIG. 245A . As mentioned above, the piezoelectric bimorph element  61025  is affixed to the reverse side of the center of the top frame  61227 , and is therefore not located on the sectional plane; instead, a perspective positional relationship as seen from above the mobile telephone  61001  is indicated by a broken line  61025 . The vibration direction of the piezoelectric bimorph element  61025  is perpendicular to the plane of the top frame  61227  (that is, the up-down direction of the mobile telephone  61001 ). 
     As is clearly shown in  FIG. 245B , between the front plate  61201   a  and the right and left frames  61201   c  and  61201   e  of the integral frame, the elastic packing ring  61065   a  serving as a vibration-absorbing material is interposed. Moreover, between the rear plate  61201   b  and the right and left frames  61201   c  and  61201   e  of the integral frame, the elastic packing ring  61065   b  serving as a vibration-absorbing material is interposed. Furthermore, to hold the integral frame between the front and rear plates  61201   a  and  61201   b , a coupling structure  61406  is provided between these. 
     In  FIG. 245C , which is a sectional view along B 2 -B 2  shown in  FIG. 235A , it is seen that, between the front plate  61201   a  and the top and bottom frames  61227  and  61201   d  of the integral frame, the elastic packing ring  61065   a  serving as a vibration-absorbing material is interposed. It is also seem that, between the rear plate  61201   b  and the top and bottom frames  61227  and  61201   d  of the integral frame, the elastic packing ring  61065   b  serving as a vibration-absorbing material is interposed. Further illustrated is the coupling structure  61406  for holding the integral frame between the front and rear plates  61201   a  and  61201   b . A plurality of such coupling structures  61406  are provided at appropriate places between the front and rear plates  61201   a  and  61201   b , though only part of them are illustrated in  FIG. 245  to avoid complexity. 
     Moreover, as will be seen from  FIG. 245C , the liquid crystal display  58205  is mounted on the structure of the front plate  61201   a , and on the structure of the front plate  61201   a , an internal structure  61048   a  of the mobile telephone  61001  is also mounted. Moreover, on the structure of the rear plate  61201   b , an internal structure  61048   b  of the mobile telephone  61001  is mounted. The weight of the internal structure  61048   a  mounted on the front plate  61201   a  and the weight of the internal structure  61048   b  mounted on the rear plate  61201   b  act, by their inertia, to suppress the vibration of the front and rear plates  61201   a  and  61201   b  respectively. 
       FIG. 246  is a partly enlarged detailed sectional view of  FIG. 245C  related to the one-hundred fifty-fifth embodiment. Such parts as appear also in  FIG. 245C  are identified by the same reference numerals, and no overlapping description will be repeated unless necessary. As will be clear from  FIG. 246 , between the front plate  61201   a  and the elastic packing ring  61065   a , and between the elastic packing ring  61065   a  and the top frame  61227 , fit-coupling structures are adopted respectively. On the other hand, also between the top frame  61227  and the elastic packing ring  61065   b , and between the elastic packing ring  61065   b  and a rear structure  61202  forming part of the rear plate  61201   b , fit-coupling structures are adopted respectively. During assembly, in the front plate  61201   a  on which the liquid crystal display  58205  is mounted, first the elastic packing ring  61065   a  and then the integral frame and the elastic packing ring  61065   b  are fitted one after the next. Then the rear structure  61202  is fitted in the integral frame and the elastic packing ring  61065   b , and with a coupling structure (screw)  61406  serving as a coupling structure, the rear structure  61202  is fixed to the front plate  61201   a . Thus, the integral frame including the front plate  61201   a  and the top frame  61227  and the rear structure  61202  are coupled together. 
     The rear plate  61201   b  has a three-layer structure composed of the above-mentioned rear structure  61202 , a rear lid  61203 , and a rear structure  61204 . A large part of the rear structure  61202  is an opening  61202   a , and even after the rear structure  61202  is fitted, the mounting of the internal structure  61048   a  is possible. The internal structure  61048   b  is mounted on the rear structure  61202  in advance before the rear structure  61202  is coupled to the front plate  61201   a . When the mounting of the internal structure  61048   a  is completed, the rear lid  61203  is fitted to the rear structure  61202  with screws  61203   a , and this ends the manufacturing process. The rear structure  61204  is, with claws  61204   a , fitted in the rear lid  61203  so that, after purchase, the user can fit and remove it on the occasions of card replacement and the like. 
     One-Hundred Fifty-Sixth Embodiment 
       FIG. 247  comprises a perspective view and sectional views related to a one-hundred fifty-sixth embodiment according to one aspect of the present invention, which is configured as a mobile telephone  62001 . The one-hundred fifty-sixth embodiment has much in common with the one-hundred fifty-fifth embodiment in  FIG. 245 ; accordingly, the same parts are identified by the same reference numerals, and no overlapping description will be repeated. The one-hundred fifty-sixth embodiment in  FIG. 247  differs from the one-hundred fifty-fifth embodiment in  FIG. 245  in the structure for suppressing air-conduction sound; accordingly, the following description focuses on differences. 
     As is clearly shown in  FIG. 247A , in the one-hundred fifty-sixth embodiment, the integral frame is covered with an elastic cover  62065   c . Moreover, as is clearly shown in  FIG. 247B , which is a view along the sectional plane B 1 -B 1  in  FIG. 247A , both ends of the elastic cover  62065   c  covering the right and left frames  62201   c  and  62201   e  have an integral structure continuous with the elastic packing rings  62065   a  and  62065   b  respectively. Also in this one-hundred fifty-sixth embodiment, as in the one-hundred fifty-fifth embodiment, the interposition of the elastic packing rings  62065   a  and  62065   b  alleviates conduction of the vibration of the top frame  62227  in the integral frame to the front and rear plates  61201   a  and  61201   b . Also in  FIG. 247C , which is a sectional view along B 2 -B 2  shown in  FIG. 247A , it is seen that both ends of the elastic cover  62065   c  have an integral structure continuous with the elastic packing rings  62065   a  and  62065   b  respectively, and that the interposition of the elastic packing rings  62065   a  and  62065   b  alleviates conduction of the vibration of the top frame  62227  to which the piezoelectric bimorph element  61025  is affixed to the front and rear plates  61201   a  and  61201   b.    
     One-Hundred Fifty-Seventh Embodiment 
       FIG. 248  comprises a perspective view and sectional views related to a one-hundred fifty-seventh embodiment according to one aspect of the present invention, which is configured as a mobile telephone  63001 . The one-hundred fifty-seventh embodiment has much in common with the one-hundred fifty-sixth embodiment in  FIG. 247 ; accordingly, the same parts are identified by the same reference numerals, and no overlapping description will be repeated. The one-hundred fifty-seventh embodiment in  FIG. 248  differs from the one-hundred fifty-sixth embodiment in  FIG. 247  in that a pair of piezoelectric bimorph elements (a left-ear piezoelectric bimorph element  63025   a  and a right-ear piezoelectric bimorph element  63025   b ) is provided, one in each of both corners of the mobile telephone  63001  such that one is controllable independently of the other. 
     As is clearly shown in  FIG. 248B , which is a view along the sectional plane B 1 -B 1  near the top frame  63227  in  FIG. 248A , at the top ends (corresponding to both corner parts of the mobile telephone  63001 ) of the right and left frames  63201   c  and  63201   e , openings are provided respectively, and penetrating through these openings, elastic supports  63065   d  and  63065   e  continuous from the elastic cover  63065   c  protrude into the mobile telephone  63001 . By the elastic supports  63065   d  and  63065   e , the right- and left-ear piezoelectric bimorph elements  63025   b  and  63025   a  are supported, at their top ends, to point downward inside the mobile telephone  63001 . Thus, the vibration of the right- and left-ear piezoelectric bimorph elements  63025   b  and  63025   a  is conducted satisfactorily from the elastic cover  63065   c  to the ear cartilage which has an a similar acoustic impedance, but is unlikely to be conducted to the right and left frames  63201   c  and  63201   e  which have a different acoustic impedance; thus, generation of air-conduction sound is further suppressed. Moreover, the right- and left-ear piezoelectric bimorph elements  63025   b  and  63025   a  can be controlled independently. The vibration direction of the right- and left-ear piezoelectric bimorph elements  63025   b  and  63025   a  is perpendicular to the plane of the front plate  61201   a  (that is, the front-rear direction of the mobile telephone  63001 ). 
     A configuration where, as described above, the right- and left-ear piezoelectric bimorph elements  63025   b  and  63025   a  are provided in both corner parts of the mobile telephone  63001  so as to be controllable independently is common to the fifty-second embodiment in  FIG. 77 ; however, unlike in the fifty-second embodiment, where one piezoelectric bimorph element is arranged in a lateral direction and the other piezoelectric bimorph element is arranged in a longitudinal direction, in the one-hundred fifty-seventh embodiment in  FIG. 248 , the right- and left-ear piezoelectric bimorph elements  63025   b  and  63025   a  are compact, are both supported in a longitudinal direction, and are arranged symmetrically left-to-right. The right- and left-ear piezoelectric bimorph elements  63025   b  and  63025   a  are fed with signals having mutually inverted phases to cancel air-conduction sound, and this feature is common to the fifty-second embodiment in  FIG. 77 . However, in the one-hundred fifty-seventh embodiment in  FIG. 248 , the left-to-right symmetric arrangement of the left- and right-ear piezoelectric bimorph elements  63025   a  and  63025   b  makes also the mechanical structure for air-conduction sound generation symmetric left-to-right, making the configuration suitable for cancellation of air-conduction sound through phase inversion. 
       FIG. 248C  shows part of a view along the sectional plane B 2 -B 2  in  FIG. 248A , and what is shown there is common to  FIG. 247C  in the one-hundred fifty-sixth embodiment except that the piezoelectric bimorph element is not arranged at the center of the top frame  63227 . By contrast,  FIG. 248D  shows part of a view along the sectional plane B 3 -B 3  near the right frame  63201   c  in  FIG. 248A . As will be clear from  FIG. 248D , at the right end (corresponding to a right corner part of the mobile telephone  63001 ) of the top frame  63227 , an opening is provided, and penetrating through this opening, an elastic support  63065   d  continuous from the elastic cover  63065   c  protrudes into the mobile telephone  63001 . By this elastic support  63065   d , the right-ear piezoelectric bimorph element  63025   b  is supported, at its top end, to point downward. The opening at the top end of the right frame  63201   c  in  FIG. 248B  and the opening at the right end of the top frame  63227  in  FIG. 248B  belong to a single continuous opening provided in a corner part, and through this single opening in the corner part, the elastic support  63065   d  protrudes into the mobile telephone  63001 . While  FIG. 248D  illustrates only the right corner part, the left corner part where the left-ear piezoelectric bimorph element  63025   a  is arranged is configured similarly, and accordingly no overlapping description will be repeated. 
     One-Hundred Fifty-Eighth Embodiment 
       FIG. 249  comprises a perspective view and sectional views related to a one-hundred fifty-eighth embodiment according to one aspect of the present invention, which is configured as a mobile telephone  64001 . The one-hundred fifty-eighth embodiment has much in common with the one-hundred fifty-seventh embodiment in  FIG. 248 ; accordingly, the same parts are identified by the same reference numerals, and no overlapping description will be repeated unless necessary. The one-hundred fifty-eighth embodiment in  FIG. 249  differs from the one-hundred fifty-seventh embodiment in  FIG. 248  in that an elastic support that protrudes in through an opening in a corner part of the integral frame to support a piezoelectric bimorph element and an elastic packing ring are provided as separate members. 
     As will be clear from  FIG. 249A , in the one-hundred fifty-eighth embodiment, as in the one-hundred fifty-fifth embodiment in  FIG. 245 , between the front plate  61201   a  and the integral frame, an elastic packing ring  64065   a  is interposed, and between the integral frame and the rear plate  61201   b , an elastic packing ring  64065   b  is interposed. Moreover in both corner parts of the top part of the mobile telephone  64001 , penetrating through openings in the integral frame, supports  64065   d  and  64065   e  of a right-ear piezoelectric bimorph element  63025   b  and a left-ear piezoelectric bimorph element  63025   a  are exposed. Also in both corner parts of a bottom part of the mobile telephone  64001 , elastic members  64065   f  or the like serving as protectors for the corner parts are provided. The protectors in both corner parts of the bottom part are configured similarly as in the forty-sixth embodiment in  FIG. 69 . 
     As will be clear from  FIG. 249B  showing a view along the sectional plane B 1 -B 1  which is a sectional plane near the top frame in  FIG. 249A , the elastic supports  63065   d  and  63065   e  which penetrate through the openings at the top end of the right and left frames  61201   c  and  61201   e  are separate members from the elastic packing rings  61065   a  and  61065   b  respectively. 
       FIG. 249C  shows part of a view along the sectional plane B 2 -B 2  in  FIG. 249A , and what is shown there is common to  FIG. 245C  in the one-hundred fifty-fifth embodiment except that the piezoelectric bimorph element is not arranged at the center of the top frame  64227 . By contrast,  FIG. 249D  shows part of a view along the sectional plane B 3 -B 3  near the right frame  64201   c  in  FIG. 249A . As will be clear from  FIG. 249D , the elastic support  63065   d  which penetrates through the opening at the right end of the top frame  64227  is a separate member from the elastic packing rings  64065   a  and  64065   b . A similar structure applies to the left corner part where the left-ear piezoelectric bimorph element  63025   a  is arranged. 
     One-Hundred Fifty-Ninth Embodiment 
       FIG. 250  comprises a perspective view and sectional views related to a one-hundred fifty-ninth embodiment according to one aspect of the present invention, which is configured as a mobile telephone  65001 . The one-hundred fifty-ninth embodiment has much in common with the one-hundred fifty-eighth embodiment in  FIG. 249 ; accordingly, the same parts are identified by the same reference numerals, and no overlapping description will be repeated. The one-hundred fifty-ninth embodiment in  FIG. 250  differs from the one-hundred fifty-eighth embodiment in  FIG. 249  in that the elastic packing rings are omitted. 
     As will be clear from  FIG. 250A , in the one-hundred fifty-ninth embodiment, as in the one-hundred fifty-eighth embodiment in  FIG. 249 , in both corner parts of a top part of the mobile telephone  65001 , penetrating through openings in the integral frame, supports  65065   d  and  65065   e  for a right-ear piezoelectric bimorph element  63025   b  and a left-ear piezoelectric bimorph element  63025   a  are exposed. Also in both corner parts of a bottom part of the mobile telephone  65001 , elastic members  65065   f  or the like serving as protectors for the corner parts are provided. However, no elastic packing rings like those in the embodiment in  FIG. 249  are provided, and the integral frame including the top frame  65227 , the right frame  65201   c , and the like lies in direct contact with the front and rear plates  61201   a  and  61201   b.    
     As will be clear from  FIG. 250B , which shows a view along the sectional plane B 1 -B 1  near the top frame in  FIG. 250A , in the openings at the top ends of the right and left frames  65201   c  and  65201   e , the elastic supports  65065   d  and  65065   e  penetrating through them are provided, and support the right- and left-ear piezoelectric bimorph elements  63025   b  and  63025   a  respectively. Moreover, as in the one-hundred fifty-seventh embodiment in  FIG. 248  and the one-hundred fifty-eighth embodiment in  FIG. 249 , the vibration of the right- and left-ear piezoelectric bimorph elements  63025   b  and  63025   a  is conducted satisfactorily from the elastic supports  65065   d  and  65065   e  to the ear cartilage which has a similar acoustic impedance, but is unlikely to be conducted to the right and left frames  65201   c  and  65201   e  which have a different acoustic impedance; thus, generation of air-conduction sound is suppressed. In the one-hundred fifty-ninth embodiment in  FIG. 250 , the component of the vibration that has conducted to the right and left frames  61201   c  and  61201   e  is conducted also to the front and rear plates  61201   a  and  61201   b.    
       FIG. 250C  shows part of a view along the sectional plane B 2 -B 2  in  FIG. 250A , and it is seen that the top frame  65227  lies in direct contact with the front and rear plates  61201   a  and  61201   b . On the other hand,  FIG. 250D  shows part of a view along the corner part B 3 -B 3  near the right frame  61201   c  in  FIG. 250A . Also in  FIG. 250D , it is seen that the top frame  65227  lies in direct contact with the front and rear plates  61201   a  and  61201   b , and it is also seen that, owing to the right-ear piezoelectric bimorph element  63025   b  being supported by the elastic support  65065   d  which penetrate through the opening at the right end of the top frame  65227 , vibration is unlikely to conduct to the top frame  65227  which has a different acoustic impedance. A similar structure applies to the left corner part where the left-ear piezoelectric bimorph element  63025   a  is arranged. 
     None of the features of the above-described embodiments of the present invention are limited to those embodiments; they may be adopted in any other embodiments. Moreover, features from different embodiments can be adopted in combined or interchanged manners. For example, in one-hundred fifty-ninth embodiment in  FIG. 250 , where the integral frame lies in direct contact with the front and rear plates, it is possible to adopt, instead of a configuration where the integral frame and the front and rear plates are provided as separate components, a configuration where the integral frame is integral with either the front or rear plate. In the one-hundred fifty-second to -ninth embodiments in  FIGS. 242 to 250 , where an integral frame is adopted, it may be divided into separate components. 
     In the one-hundred fifty-fifth to -ninth embodiments in  FIGS. 245 to 250 , the piezoelectric bimorph elements may be supported in any manner other than specifically described in connection with those embodiments. For example, in the one-hundred fifty-seventh to -ninth embodiments in  FIGS. 248 to 250 , the right- and left-ear piezoelectric bimorph elements  63025   b  and  63025   a  may be held such that their vibration direction is perpendicular to the plane of the top frame  63227  or the like (that is, the up-down direction of the mobile telephone  61001 ). Reversely, in the one-hundred fifty-fifth embodiment in  FIG. 245  or the like, the vibration direction of the piezoelectric bimorph element  61025  may be perpendicular to the plane of the front plate  61201   a  (that is, the front-rear direction of the mobile telephone  65001 ) as in the one-hundred fifty-seventh embodiment in  FIG. 248  or the like. In any embodiment, the piezoelectric bimorph element may be held such that its vibration direction is inclined relative to the front plate or the top frame as in the one-hundred fifty-fourth embodiment in  FIG. 244 . 
     Furthermore, in the one-hundred fifty-fifth embodiment in  FIG. 245  and the one-hundred fifty-sixth embodiment in  FIG. 247 , instead of one piezoelectric bimorph element being arranged at the center of the top frame, as in the one-hundred fifty-seventh to -ninth embodiments in  FIGS. 248 to 250 , a right-ear piezoelectric bimorph element and a left-ear piezoelectric bimorph element may be arranged in both corner parts, respectively, of a top part of the mobile telephone. In that case, as in the structures of the one-hundred fifty-fifth embodiment in  FIG. 245  and the one-hundred fifty-sixth embodiment in  FIG. 247 , the right- and left-ear piezoelectric bimorph elements are affixed directly, with no elastic body interposed, to both ends of the top frame or to the top ends of the right and left frames. 
     One-Hundred Sixtieth Embodiment 
       FIG. 251  is a front view of a one-hundred sixtieth embodiment according to one aspect of the present invention, which is configured as a hearing device, more specifically as a stereo headset  66001  for mobile telephones and mobile music terminals.  FIG. 251  is a front view (corresponding to a side of the human face) of, out of the stereo headset  66001 , a right-ear headset worn on the right ear  28 , and for simplicity&#39;s sake, the part of the face other than the right ear  28  is omitted from illustration. Moreover, to avoid complicated illustration, the ear  28  is indicated by solid lines, and the structure of the right-ear headset worn on it is indicated by broken lines. The exterior appearance of a left-ear headset in the one-hundred sixtieth embodiment is largely common to that of the right-ear headset shown in  FIG. 251 , and therefore, for simplicity&#39;s sake, the following description focuses on the right-ear headset. Differences between the right- and left-ear headsets in internal configuration etc. will be described later. 
     The right-ear headset includes a right-ear cartilage conduction vibration unit  66024  in a shape that fits in the cavum conchae  28   e  of the right ear  28 . The vibration of the surface of the right-ear cartilage conduction vibration unit  66024  is conducted to the ear cartilage around the cavum conchae  28   e  and the external auditory meatus opening  30   a , such as that in the tragus  32 , via a large contact area, and produces efficient cartilage conduction. Thus, in the one-hundred sixtieth embodiment, the right-ear cartilage conduction vibration unit  66024  in a shape that fits in the cavum conchae  28   e  is configured to vibrate as a whole, and the vibration of no part of it is suppressed. Specifically, the right-ear cartilage conduction vibration unit  66024  has, embedded in it as vibration sources, two compact piezoelectric bimorph elements  66025   a  and  66025   b , and their vibration conducts to the entire right-ear cartilage conduction vibration unit  66024 . Moreover, at the center of the right-ear cartilage conduction vibration unit  66024 , a through-hole  66024   a  is provided, so that, even with the right-ear cartilage conduction vibration unit  66024  fitted in the cavum conchae  28   e , air-conduction sound from outside can enter the external auditory meatus opening  30   a  and reach the eardrum. As illustrated, the compact piezoelectric bimorph elements  66025   a  and  66025   b  are arranged on both sides of the through-hole  66024   a  across it. 
     The right-ear cartilage conduction vibration unit  66024  fits in the cavum conchae  28   e , and vibrates as a whole so that vibration conducts efficiently to the ear cartilage around the external auditory meatus opening  30   a  via a large contact area; however, since the right-ear cartilage conduction vibration unit  66024  is not so large in size, the vibration generated from its surface is weak. Moreover, as will be described later, the vibration energy of the entire right-ear cartilage conduction vibration unit  66024  is concentrated to conduct exclusively to the ear cartilage, so as to suppress conduction of vibration to the other part of the right-ear headset and thereby suppress generation of air-conduction sound from its surface. 
     The two compact piezoelectric bimorph elements  66025   a  and  66025   b  embedded in the right-ear cartilage conduction vibration unit  66024  have basically identical frequency characteristics, and since they are compact, the vibration acceleration level is relatively high in a high frequency range compared with in a low frequency range. On the other hand, as to the frequency characteristics of the ear cartilage in cartilage conduction, for example as shown in  FIG. 132B , the vibration acceleration level is relatively low in a high frequency range compared with in a low frequency range. Accordingly, in one-hundred sixtieth embodiment, compact piezoelectric bimorph elements having a relatively high vibration acceleration level in a high frequency range are adopted, and a plurality of them are used to augment the absolute level of the vibration acceleration in a high frequency range. On the other hand, also as to the vibration acceleration level in a low frequency range which is relatively low because of the compactness, its absolute level is augmented by use of two compact piezoelectric bimorph elements  66025   a  and  66025   b . Using piezoelectric bimorph elements with identical frequency characteristics leaves the vibration acceleration level in a low frequency range relatively low; however, with this, the frequency characteristics of the ear cartilage in cartilage conduction is in a complementary relationship as mentioned above, and thus the frequency characteristics of the sound that eventually reaches the eardrum are flatter than those of the vibration acceleration of the piezoelectric bimorph elements. Based on the foregoing, the compact right-ear cartilage conduction vibration unit  66024  is configured to achieve efficient cartilage conduction despite the smallness of the surface area that causes air-conduction sound. 
     As shown in  FIG. 251 , the right-ear headset has a right-ear hook  66089   a . The right-ear hook  66089   a  and the right-ear cartilage conduction vibration unit  66024  are coupled together by a right elastic coupling  66073   a  which has an acoustic impedance different from that of the right-ear cartilage conduction vibration unit  66024 . Thus, conduction of the vibration of the right-ear cartilage conduction vibration unit  66024  to the right-ear hook  66089   a  is suppressed, and the vibration of the entire right-ear cartilage conduction vibration unit  66024  is concentrated to conduct exclusively to the ear cartilage. 
     The right-ear hook  66089   a  communicates with a mobile telephone or a mobile music terminal by near-field wireless communication, and transmits a driving signal to the right-ear cartilage conduction vibration unit  66024  via a signal line laid inside the right elastic coupling  66073   a ; it also transmits the sound collected by a microphone  66023  to the mobile telephone or the like. Electric power for these functions is supplied from a power source unit  66048  (see  FIG. 252 ), including a right battery  66048   a  and the like, provided in the right-ear hook  66089   a . The weight of the right battery  66048   a  housed in a battery holder  66048   b  (see  FIG. 252 ), by its inertia, suppresses the vibration of the right-ear hook  66089   a , and reduces the air-conduction sound generated from its surface. 
     The right-ear hook  66089   a  and the left-ear headset are connected together via a flexible cable  66081 . Through the cable  66081 , there are laid, as will be described later, a signal line for transmitting a drive signal to a left-ear cartilage conduction vibration unit and a connection line leading to a left battery  66048   d  (see  FIG. 252 ). 
       FIG. 252  is an overall block diagram of the stereo headset  66001  of the one-hundred sixtieth embodiment in  FIG. 251 . Such parts as appear also in  FIG. 251  are identified by the same reference numerals, and no overlapping description will be repeated unless necessary. 
     The right-ear hook  66089   a  includes a control unit  66039  which controls the entire stereo headset  66001 , and communicates with a mobile telephone or a mobile music terminal via a near-field communication unit  66046  based on operation on the operation unit  66009 . Then, based on a received sound signal or audio signal, it drives the drive unit  66036 , and drives the compact piezoelectric bimorph elements  66025   a  and  66025   b  of the right-ear cartilage conduction vibration unit  66024  via the signal line laid inside the right elastic coupling  66073   a . It further transmits the sound signal collected by the microphone  66023  to the mobile telephone or the like via the near-field communication unit  66046 . 
     On the other hand, a left-ear hook  66089   b  has the same shape as the right-ear hook  66089   a  in terms of exterior appearance as mentioned above. As in the right-ear cartilage conduction vibration unit  66024 , inside a left-ear cartilage conduction vibration unit  60026 , as vibration sources, two compact piezoelectric bimorph elements  66025   c  and  66025   d  are embedded, and their vibration conducts to the entire left-ear cartilage conduction vibration unit  60026 . Through a through-hole  66026  provided at the center of the left-ear cartilage conduction vibration unit  60026 , even with the left-ear cartilage conduction vibration unit  60026  fitted in the cavum conchae of the left ear, air-conduction sound from outside can reach the eardrum through the external auditory meatus opening of the left ear, as in the right-ear cartilage conduction vibration unit  66024 . 
     As a result of the internal configuration necessary for the control function of the stereo headset  66001  being concentrated in the right-ear hook  66089   a , the left-ear hook  66089   b  functions exclusively as an ear hook for the left-ear cartilage conduction vibration unit  60026 . As in the right-ear headset, the left-ear hook  66089   b  and the left-ear cartilage conduction vibration unit  60026  are coupled together by a left elastic coupling  66073   b . As in the right-ear headset, the acoustic impedance of the left elastic coupling  66073   b  differs from that of the left-ear cartilage conduction vibration unit  60026 . Thus, as with the right-ear headset, conduction of the vibration of the left-ear cartilage conduction vibration unit  60026  to the left-ear hook  66089   b  is suppressed, and the vibration energy of the entire left-ear cartilage conduction vibration unit  60026  is concentrated to conduct exclusively to the ear cartilage. 
     Next, the configuration of the power source unit  66048  will be described. The power source unit  66048  basically belongs to the internal configuration of the right-ear hook  66089   a , but the battery housing is divided into two parts, of which one is arranged in the right-ear hook  66089   a  as the battery holder  66048   b  for housing the right battery  66048   a , while another battery holder  66048   c  is arranged in the left-ear hook  66089   b  to house a left battery  66048   d . Thus, the weight of the left battery  66048   d , by its inertia, suppresses the vibration of the left-ear hook  66089   b , and reduces the air-conduction sound generated from its surface. In this way, with a view to suppressing air-conduction sound from the left-ear hook  66089   b , the weight of the battery is distributed partly to the left-ear hook  66089   b . As illustrated, the right and left batteries  66048   a  and  66048   d  are connected in series to secure the supply voltage needed in the power source unit  66048  arranged in the right-ear hook  66089   a.    
     In a cable  66081  which connects the right- and left-ear hook  66089   a  and  66089   b  together, there are laid a connection line for connection between the right and left batteries  66048   a  and  66048   d  as described above and a signal line for transmission of a left-ear drive signal from the drive unit  66036  to the compact piezoelectric bimorph elements  66025   c  and  66025   d.    
     One-Hundred Sixty-First Embodiment 
       FIG. 253  is a front view of a one-hundred sixty-first embodiment according to one aspect of the present invention, which is configured as a hearing device, more specifically as a stereo headset  67001  for mobile telephones and mobile music terminals. The one-hundred sixty-first embodiment shown in  FIG. 253  has much in common with the one-hundred sixtieth embodiment in  FIG. 251 ; accordingly, similar parts are identified by the same reference numerals, and no overlapping description will be repeated unless necessary. For simplicity&#39;s sake, the face is omitted from illustration except for the right ear  28  and the left ear  30 . As in  FIG. 251 , the right and left ears  28  and  30  are indicated by solid lines, and the structure of the headset is indicated by broken lines.  FIG. 253A  is a front view of the right-ear headset in the one-hundred sixty-first embodiment, and its configuration is largely common to  FIG. 251  showing the one-hundred sixtieth embodiment. However, as will described later, the power source unit is not divided, and the weight of a battery  67048   e  concentrates in the right-ear hook  67089   a . Also as will be described later, the flexible cable  67081  connects directly to the left-ear cartilage conduction vibration unit  67026 , and in it there is laid only a signal line for transmission of a driving signal to the left-ear cartilage conduction vibration unit  67026 . 
       FIG. 253B  is a front view of the left-ear headset in the one-hundred sixty-first embodiment. The left-ear headset in the one-hundred sixty-first embodiment has no ear hook, and is basically composed solely of the left-ear cartilage conduction vibration unit  67026 . Instead, to keep the left-ear cartilage conduction vibration unit  67026  stably in the worn state fitted in the cavum conchae of the left ear  30 , the cable  67081  is given a sufficient length to be hung around the ear before being connected to the right-ear hook  67089   a . Moreover, to prevent vibration from conducting via the tense cable  67081  to the right-ear hook  67089   a  by the principle of a string telephone, the cable  67081  is given a sufficient length to slacken freely behind the neck in the worn state. The vibration of the two compact piezoelectric bimorph elements  67025   c  and  67025   d  conducts to the entire left-ear cartilage conduction vibration unit  67026 , as in the one-hundred sixtieth embodiment. Through a through-hole  67026   a  provided at the center of the left-ear cartilage conduction vibration unit  67026 , even with the left-ear cartilage conduction vibration unit  67026  fitted in the cavum conchae of the left ear  30 , air-conduction sound from outside can reach the eardrum through the external auditory meatus opening of the left ear  30 , as in the one-hundred sixtieth embodiment. 
       FIG. 254  is an overall block diagram of the stereo headset  67001  of the one-hundred sixty-first embodiment in  FIG. 253 . Such parts as appear also in  FIG. 253  are identified be the same reference numerals, and no overlapping description will be repeated unless necessary.  FIG. 254  has much in common with the block diagram shown in  FIG. 252  in connection with the one-hundred sixtieth embodiment; accordingly, similar parts are identified by the same reference numerals, and no overlapping description will be repeated unless necessary. 
     A first difference of  FIG. 254  related to the one-hundred sixty-first embodiment from  FIG. 252  related to the one-hundred sixtieth embodiment is that, as mentioned above, the power source unit  67048  is not divided but is provided in a consolidated manner in the right-ear hook  67089   a  and all the battery  67048   e  for securing the needed voltage is housed in the battery holder  67048   b  in the power source unit  67048 . A second difference is that no left-ear hook is provided and the flexible cable  67081  connects directly to the left-ear cartilage conduction vibration unit  67026 , the cable  67081  having laid in it only a signal line for transmission of a left-ear driving signal from the drive unit  66036  to the compact piezoelectric bimorph elements  67025   c  and  67025   d . As mentioned above, the cable  67081  is flexible, and is given a sufficient length to be worn slackly so as not to act as a string telephone, and this prevents the vibration of the left-ear cartilage conduction vibration unit  67026  from conducting via the cable  67081  to the right-ear hook  67089   a.    
     One-Hundred Sixty-Second Embodiment 
       FIG. 255  is a system block diagram of a one-hundred sixty-second embodiment according to one aspect of the present invention, which is configured as a hearing device, more specifically as stereo earphones  68001  for mobile telephones and mobile music terminals, and a mobile music terminal  69001 . The one-hundred sixty-second embodiment shown in  FIG. 255  has much in common with the one-hundred sixty-first embodiment shown in  FIGS. 253 and 254 ; accordingly, similar parts are identified by the same reference numerals, and no overlapping description will be repeated unless necessary. For simplicity&#39;s sake, the face is omitted from illustration except for the right ear  28  and the left ear  30 . As in  FIG. 251  and the like, the right and left ears  28  and  30  are indicated by solid lines, and the structure of the stereo earphones  68001  is indicated by broken lines. 
     In the one-hundred sixty-second embodiment in  FIG. 255 , the left-ear earphone worn on the left ear  30  has quite the same configuration as the left-ear headset in the one-hundred sixty-first embodiment shown in  FIG. 253B . The flexible cable  67081  is connected directly to the mobile music terminal  69001 , which will be described later. 
     The right-ear earphone worn on the right ear  28  in the one-hundred sixty-second embodiment in  FIG. 255  has quite the same configuration as the left-ear earphone worn on the left ear  30  in the same figure, and is connected, like the left ear earphone, via a flexible cable  68081  directly to the mobile music terminal  69001 , which will be described later. A right-ear cartilage conduction vibration unit  68024 , compact piezoelectric bimorph elements  68025   a  and  68025   b , and a through-hole  68024   a  in the right-ear earphone correspond to the left-ear cartilage conduction vibration unit  67026 , the compact piezoelectric bimorph elements  66025   c  and  66025   d , and the through-hole  67026   a  in the left-ear earphone, and accordingly no overlapping description will be repeated. 
     The mobile music terminal  69001  in the one-hundred sixty-second embodiment in  FIG. 255  downloads music data via a near-field communication unit  69046  and stores it in a storage unit  69037 . A control unit  69039  transmits, according to operation on an operation unit  69009  performed while viewing display on a display unit  69005 , a stereo drive signal based on the music data in the storage unit  69037  from the drive unit  69036  to the right- and left-ear cartilage conduction vibration units  68024  and  68026 . 
     The mobile music terminal  69001  includes a microphone  69023 , and by communicating with a mobile telephone via the near-field communication unit  69046 , can function, along with the stereo earphones  68001 , as a stereo headset for the mobile telephone. A power source unit  69048  including a battery holder  69048   e  for housing a battery  69048   b  supplies electric power to the entire mobile music terminal  69001 , as does the power source unit  67048  to the entire right-ear hook  67089   a  in the one-hundred sixty-first embodiment in  FIG. 254 . 
     Also in the one-hundred sixty-second embodiment in  FIG. 255 , the cables  67081  and  68081  are flexible, and are given a sufficient length to be worn slackly so as not to act as a string telephone, and this prevents the vibration of the right- and left-ear cartilage conduction vibration units  68024  and  68026  from conducting via the cables  67081  and  68081  to the mobile music terminal  69001 . This prevents the mobile music terminal  69001  from vibrating and generating air-conduction sound from its surface. 
       FIG. 256  comprises plan views showing modified examples of the cartilage conduction vibration units used in the one-hundred sixtieth to sixty-second embodiments. Although, for convenience&#39; sake, only modified examples of the right-ear cartilage conduction vibration unit  66024  in one-hundred sixtieth embodiment are illustrated, any of them can be adopted in any other embodiment, and in the left-ear cartilage conduction vibration unit.  FIG. 256A  shows the same structure as that used in the one-hundred sixtieth to sixty-second embodiments, and are identified by the same reference numerals. 
     By contrast,  FIG. 256B  shows a structure where, around the through-hole  66024   a , at equal angular intervals, three compact piezoelectric bimorph elements  66025   e ,  66025   e , and  66025   e  having identical frequency characteristics are arranged as vibration sources.  FIG. 256C  shows a structure where, around the through-hole  66024   a , at equal angular intervals, four compact piezoelectric bimorph elements  66025   h ,  66025   i ,  66025   j , and  66025   k  having identical frequency characteristics are arranged as vibration sources.  FIG. 256D  shows, as the simplest structure for a case where sufficient vibration energy is available, a structure where, by the side of the through-hole  66024   a , one compact piezoelectric bimorph element  660251  is arranged as a vibration source. 
       FIG. 256E  shows a structure where, around the through-hole  66024   a , a bent piezoelectric bimorph element  66025   m  is provided. With this structure, despite the cartilage conduction vibration unit having the through-hole  66024   a  and having a small surface area leading to air-conduction sound, the piezoelectric bimorph element  66025   m  can be given a long shape by being bent to fit around the circumference of the through-hole  66024   a , and this is suitable to alleviate an excessive drop of a low frequency component in the frequency characteristics.  FIG. 256F  shows a structure where bent piezoelectric bimorph elements  66025   n  and  66025   o  similar to the one in  FIG. 256E  are provided on opposite sides of the through-hole  66024   a  to augment the vibration energy generally while maintaining identical frequency characteristics. 
       FIG. 256G  shows a structure where, at the center of a cartilage conduction vibration unit  70025 , one compact piezoelectric bimorph element  70025  is arranged as a vibration source, and on opposite sides of it across it, a pair of through-holes  70024   a  and  70024   b  are provided. With this structure, even in a case where one piezoelectric bimorph element  70025  is provided, it can be arranged at a balanced position in the cartilage conduction vibration unit  70024 .  FIG. 256H  shows a structure where the advantage that the compact piezoelectric bimorph element  71025  can be arranged at the center is exploited by extending it in the diametrical direction, thereby to alleviate an excessive drop of a low frequency component in the frequency characteristics. 
       FIG. 256I  shows a structure where, as in  FIG. 256G , at the center of the cartilage conduction vibration unit  71024 , one compact piezoelectric bimorph element  70025  is arranged as a vibration source, and in addition, around it, at equal angular intervals, a plurality of (for example, six) through-holes  71024   a ,  71024   b ,  71024   c ,  71024   d ,  71024   e , and  71024   f  are provided. Also with this structure, in a case where one piezoelectric bimorph element  70025  is provided, it can be arranged at a balanced position in the cartilage conduction vibration unit  71024 . 
     As shown in  FIG. 256  by way of various examples, with a configuration where, for efficient cartilage conduction, a cartilage conduction vibration unit is vibrated as a whole and is fitted in the cavum conchae  28  to obtain a large area of contact with the ear cartilage and on the other hand where, to reduce a surface area leading to generation of air-conduction sound, the cartilage conduction vibration unit is made compact, it is possible, by changing the number and shape of piezoelectric bimorph elements and the number and shape of through-holes, to adjust the magnitude of the vibration energy and the frequency characteristics. 
     The various features of the embodiments described above are not limited to those embodiments, and may be adopted in any other embodiments so long as they provide their benefits. Features from different embodiments may be adopted in an integrated manner in a single embodiment. For example, the right and left elastic couplings  66073   a  and  66073   b  may be configured as a flexible cable as used in the one-hundred sixty-second embodiment in  FIG. 255 , and may thereby be exempted from an active supporting function. 
     In the one-hundred sixty-second embodiment in  FIG. 255 , the mobile music terminal  69001  may be configured as a mobile telephone, with the right- and left-ear cartilage conduction vibration units  68024  and  67026  connected directly to the mobile telephone via the cables  67081  and  68081 . In that case, the right- and left-ear cartilage conduction vibration units  68024  and  67026  function as stereo earphones for the mobile telephone. At that time, needless to say, the cables  67081  and  68081  join at one end in a stereo plug, which is plugged into a stereo jack in the mobile telephone. 
     One-Hundred Sixty-Third Embodiment 
       FIG. 257  comprises a perspective view and a sectional view related to a one-hundred sixty-third embodiment according to one aspect of the present invention, which is configured as a mobile telephone  72001 .  FIG. 257A  is a perspective view of the mobile telephone  72001  of the one-hundred sixty-third embodiment as seen from in front, and as in the forty-sixth embodiment in  FIG. 69 , in four corners of the mobile telephone  72001  which tend to be exposed to impact when it is dropped inadvertently or the like, elastic members  72063   a ,  72063   b ,  72063   c , and  72063   d  serving as protectors are provided. Moreover, the two elastic members  72063   a  and  72063   b  in the two upper corners double as cartilage conduction units structured as described later, and make contact with the ear cartilage. Accordingly, at least for the elastic members  72063   a  and  72063   b , an elastic material having an acoustic impedance similar to that of the ear cartilage is adopted (such as silicone rubber, a mixture of silicone rubber and butadiene rubber, natural rubber, or a structure having air bubbles sealed in those materials, or a structure having a layer of air bubbles sealed in, separate from, a thin film of a synthetic resin, as seen in a transparent packing sheet material). 
       FIG. 257B  is a partly enlarged sectional view of the mobile telephone  72001  as cut along a plane perpendicular to its front and side faces on the sectional plane B 1 -B 1  in  FIG. 257A , and shows the internal structure of the elastic member  72063   b , which is assumed to make contact with the right ear cartilage. As to the elastic member  72063   a  for contact with the left ear cartilage shown in  FIG. 257A , its internal structure is symmetric left-to-right with, and similar to, that of the elastic member  72063   b , and is therefore omitted from illustration in  FIG. 257B  and from separate description. Though not appearing in the  FIG. 257A , which is a simplified schematic diagram, in practice the mobile telephone  72001  has its corner parts rounded to have curved surfaces as shown in the enlarged view in  FIG. 257B , and thus consideration is given to conformable contact with the ear cartilage. 
     As shown in  FIG. 257B , the one-hundred sixty-third embodiment adopts an electromagnetic vibrating element. Its structure is as follows: to a casing structure  72001   a  of the mobile telephone  72001 , a voice coil bobbin  72024   k  is fixed, and around it, a voice coil  72024   m  is wound. 
     In a corner part of the mobile telephone  72001 , on the outside of the casing structure  72001   a , the elastic member  72063   b  is laid, of which part is exposed to the inside of the mobile telephone  72001  through an opening  72001   b  in the casing structure  72001   a . To the exposed part of the elastic member  72063   b , a yoke  72024   h  of the electromagnetic vibrating element is fixed, on which a magnet  72024   f  and a central magnetic pole  72024   g  are held. Furthermore, to the magnet  72024   f  and the central magnetic pole  72024   g , a top plate  72024   j  having a gap is fixed. In the gap in the top plate  72024   j , the voice coil  72024   m  is inserted with no contact with the top plate  72024   j.    
     Between the set comprising the magnet  72024   f , the central magnetic pole  72024   g , the yoke  72024   h , and the top plate  72024   j  and the set comprising the voice coil bobbin  72024   k  and the voice coil  72024   m , only the elastic member  72063   b  is interposed, and thus the yoke  72024   h  and the like are movable relative to the voice coil bobbin  72024   k  and the like. In this structure, when a sound signal is fed to the voice coil  72024   m , the yoke  72024   h  and the like vibrate relative to the voice coil bobbin  72024   k  and the like, and the vibration conducts via the elastic member  72063   b  to the ear cartilage in contact with it. 
     As described above, in the one-hundred sixty-third embodiment, between the pair of parts of the electromagnetic vibrating element which move relative to each other (the part comprising the magnet  72024   f , the central magnetic pole  72024   g , the yoke  72024   h , and the top plate  72024   j  and the part comprising the voice coil bobbin  72024   k  and the voice coil  72024   m ), the elastic member  72063   b  is interposed to allow their movement relative to each other, and vibration is extracted from the elastic member  72063   b . As will be clear from  FIG. 257B , the vibration direction in the one-hundred sixty-third embodiment is perpendicular to the front face. 
     The pair of parts may be arranged the other way around (that is, the parts comprising the yoke  72024   h  and the like on the casing structure  72001   a , and the parts comprising the voice coil bobbin  72024   k  and the like on the elastic member  72063   b . Whether or not to adopt this arrangement can be determined with attention paid to the fact that the weight of the part comprising the voice coil bobbin  72024   k  and like is larger than the weight of the part comprising the yoke  72024   h  and the like, and with overall consideration given to the inertia of the vibrating part, the elastic modulus of the elastic member  72063   b , the thickness of the elastic member  72063   b , the energy efficiency eventually extractable from the elastic member  72063   b , the response frequency characteristics of the vibrating structure with consideration given to the audio frequency range, the frequency characteristics of cartilage conduction, and the like. 
     One-Hundred Sixty-Fourth Embodiment 
       FIG. 258  comprises a perspective view and a sectional view related to a one-hundred sixty-fourth embodiment according to one aspect of the present invention, which is configured as a mobile telephone  73001 . Like the one-hundred sixty-third embodiment in  FIG. 257 , the one-hundred sixty-fourth embodiment adopts an electromagnetic vibrating element. The internal structure of the electromagnetic vibrating element in the one-hundred sixty-fourth embodiment has much in common with that in the one-hundred sixty-third embodiment; accordingly, similar parts are identified by similar reference numerals, and no overlapping description will be repeated unless necessary. 
       FIG. 258A  is a perspective view of the mobile telephone  73001  of the one-hundred sixty-fourth embodiment as seen from in front, and a large part of the front face is configured as a liquid crystal display  73205  having a touch panel function. Accordingly, an elastic member  73063   b  that functions as a right-ear cartilage conduction unit is provided near a top end part of the right side face of the mobile telephone  73001 . Though hidden in  FIG. 258A , a similar elastic member that functions as a left-ear cartilage conduction unit is provided in a top end part of the left side face of the mobile telephone  73001 . Moreover, as will be described in detail below, the elastic member  73063   b  that functions as a right-ear cartilage conduction unit is configured as a part of an electromagnetic vibrating unit component. 
       FIG. 258B  is a partly enlarged sectional view of the mobile telephone  73001  as cut along a plane perpendicular to its top and side faces on the sectional plane B 2 -B 2  in  FIG. 258A , and shows in detail the structure of the electromagnetic vibrating unit component. As mentioned above, a similar electromagnetic vibrating unit component is provided in a top end part of the left side face of the mobile telephone  73001 . 
     As is clearly shown in  FIG. 258B , in the one-hundred sixty-fourth embodiment, the voice coil bobbin  73024   k  is extended to form a housing  73024   a , and supports the elastic member  73063   b  which serves as a cartilage conduction unit. The housing  73024   a  is supported on the casing structure  73001   a . To the voice coil bobbin  73024   k , the voice coil  73024   m  is wound, and to the inside of the elastic member  73063   b , the yoke  73024   h  of the electromagnetic vibrating element is fixed, as in the one-hundred sixty-third embodiment. 
     In this structure, when a sound signal is fed to the voice coil  72024   m , as in the one-hundred sixty-third embodiment, the yoke  72024   h  and the like vibrate relative to the voice coil bobbin  73024   k  and the like, and the vibration conducts via the elastic member  73063   b  to the ear cartilage in contact with it. 
     Also in the one-hundred sixty-fourth embodiment, between the pair of parts of the electromagnetic vibrating element which move relative to each other (the part comprising the magnet  72024   f , the central magnetic pole  72024   g , the yoke  72024   h , and the top plate  72024   j  and the part comprising the voice coil bobbin  73024   k , the housing  73024   a , and the voice coil  72024   m ), the elastic member  73063   b  is interposed to allow their movement relative to each other, and vibration is extracted from the elastic member  73063   b . In the one-hundred sixty-fourth embodiment, as will be clear from  FIG. 258B , the vibration direction is perpendicular to the side face. 
     One-Hundred Sixty-Fifth Embodiment 
       FIG. 259  comprises a perspective view and a sectional view related to a one-hundred sixty-fifth embodiment according to one aspect of the present invention, which is configured as a mobile telephone  74001 . Like the one-hundred sixty-fourth embodiment in  FIG. 258 , the one-hundred sixty-fifth embodiment adopts an electromagnetic vibrating element. The internal structure of the electromagnetic vibrating element in the one-hundred sixty-fifth embodiment has much in common with that in the one-hundred sixty-fourth embodiment; accordingly, similar parts are identified by similar reference numerals, and no overlapping description will be repeated unless necessary. Like the one-hundred sixty-fourth embodiment, the one-hundred sixty-fifth embodiment is configured as an electromagnetic vibrating unit component, a difference being that it is arranged in a corner part of the mobile telephone  74001 . 
       FIG. 259A  is a perspective view of the mobile telephone  74001  of the one-hundred sixty-fifth embodiment as seen from in front, and as in the one-hundred sixty-fourth embodiment, a large part of the front face is configured as a liquid crystal display  73205  having a touch panel function. Accordingly, an elastic member  74063   a  that functions as a left-ear cartilage conduction unit and an elastic member  74063   b  that functions as a right-ear cartilage conduction unit are provided in both corner parts, respectively, of a top part of the mobile telephone  74001 . 
       FIG. 259B  is a partly enlarged sectional view of the mobile telephone  74001  as cut along a plane perpendicular to its top and side faces on the sectional plane B 2 -B 2  in  FIG. 259A , and shows in the detailed structure of the electromagnetic vibrating unit component for arrangement in a corner part. An electromagnetic vibrating unit component having the same structure and including a left-ear cartilage conduction unit  74063   a  is provided in a top end part of the left side face of the mobile telephone  73001 . 
     As is clearly shown in  FIG. 259B , also in the one-hundred sixty-fifth embodiment, the voice coil bobbin  74024   k  is extended to form a housing  74024   a , and supports the elastic member  74063   b . The housing  74024   a  is supported on the casing structure  74001   a  in a corner part of the mobile telephone  74001 . To the voice coil bobbin  74024   k , the voice coil  72024   m  is wound, and to the inside of the elastic member  74063   b , the yoke  74024   h  of the electromagnetic vibrating element is fixed, as in the one-hundred sixty-third and -fourth embodiments. 
     In this structure, when a sound signal is fed to the voice coil  72024   m , as in the one-hundred sixty-third and -fourth embodiments, the yoke  72024   h  and the like vibrate relative to the voice coil bobbin  74024   k  and the like, and the vibration conducts via the elastic member  74063   b  to the ear cartilage in contact with it. 
     Also in the one-hundred sixty-fifth embodiment, between the pair of parts of the electromagnetic vibrating element which move relative to each other (the part comprising the magnet  72024   f , the central magnetic pole  72024   g , the yoke  72024   h , and the top plate  72024   j  and the part comprising the voice coil bobbin  74024   k , the housing  74024   a , and the voice coil  72024   m ), the elastic member  74063   b  is interposed to allow their movement relative to each other, and vibration is extracted from the elastic member  74063   b . In the one-hundred sixty-fifth embodiment, as will be clear from  FIG. 259B , the vibration direction points to the vertex of the corner part. 
     One-Hundred Sixty-Sixth Embodiment 
       FIG. 260  comprises a perspective view and a sectional view related to a one-hundred sixty-sixth embodiment according to one aspect of the present invention, which is configured as a mobile telephone  75001 . Like the one-hundred sixty-third to -fifth embodiments, the one-hundred sixty-sixth embodiment adopts an electromagnetic vibrating element. The internal structure of the electromagnetic vibrating element in the one-hundred sixty-sixth embodiment has much in common with that in the one-hundred sixty-fourth embodiment; accordingly, similar parts are identified by similar reference numerals, and no overlapping description will be repeated unless necessary. Like the one-hundred sixty-fourth embodiment, the one-hundred sixty-sixth embodiment is configured as an electromagnetic vibrating unit component, a difference being that the cartilage conduction unit is a rigid body. 
       FIG. 260A  is a perspective view of the mobile telephone  75001  of the one-hundred sixty-sixth embodiment as seen from in front, and as in the one-hundred sixty-fourth and -fifth embodiments, a large part of the front face is configured as a liquid crystal display  73205  having a touch panel function. Accordingly, a left-ear cartilage conduction unit  75026   h  and a right-ear cartilage conduction unit  75024   h  are provided on the top side of the mobile telephone  75001 . As mentioned above, these cartilage conduction units are rigid bodies. 
       FIG. 260B  is a partly enlarged sectional view of the mobile telephone  75001  as cut along a plane perpendicular to its top and side faces on the sectional plane B 2 -B 2  in  FIG. 260A , and shows in detail the structure of the electromagnetic vibrating unit component for arrangement on the top side. As is clearly shown in  FIG. 260B , also in the one-hundred sixty-sixth embodiment, the voice coil bobbin  75024   k  is extended to form a housing  75024   a . In the one-hundred sixty-sixth embodiment, however, the yoke  75064   h  of the electromagnetic vibrating element is exposed on the surface of the mobile telephone  75001 , and doubles as a rigid-body cartilage conduction unit (identified by the same reference numeral  75024   h ). The part serving as the cartilage conduction unit comprising the yoke  75024   h  and the components integral with it, namely the magnet  72024   f , the central magnetic pole  72024   g  and the top plate  72024   j , is supported via the elastic member  75065  on the housing  75024   a.    
     In this structure, when a sound signal is fed to the voice coil  72024   m , the yoke  75024   h  and the like supported via the elastic member  75065  on the housing  75024   a  vibrate relative to the voice coil bobbin  75024   k  and the like, and the vibration conducts to the ear cartilage in contact with the yoke  73024   h  serving as the cartilage conduction unit. 
     Also in the one-hundred sixty-sixth embodiment, between the pair of parts of the electromagnetic vibrating element which move relative to each other (the part comprising the magnet  72024   f , the central magnetic pole  72024   g , the yoke  75024   h , and the top plate  72024   j  and the part comprising the voice coil bobbin  75024   k , the housing  75024   a , and the voice coil  72024   m ), the elastic member  75065  is interposed to allow their movement relative to each other, and vibration is extracted from one of the pair of parts of the electromagnetic vibrating element (in the one-hundred sixty-sixth embodiment, the part comprising the yoke  75024   h  and the like). In the one-hundred sixty-sixth embodiment, as will be clear from  FIG. 260B , the vibration direction is perpendicular to the top side. 
     One-Hundred Sixty-Seventh Embodiment 
       FIG. 261  comprises a perspective view and a sectional view related to a one-hundred sixty-seventh embodiment according to one aspect of the present invention, which is configured as a mobile telephone  76001 . Like the one-hundred sixty-third to -sixth embodiments, the one-hundred sixty-seventh embodiment adopts an electromagnetic vibrating element. The internal structure of the electromagnetic vibrating element in the one-hundred sixty-seventh embodiment has much in common with that in the one-hundred sixty-fourth embodiment; accordingly, similar parts are identified by similar reference numerals, and no overlapping description will be repeated unless necessary. Like the one-hundred sixty-fourth embodiment, the one-hundred sixty-seventh embodiment is configured as an electromagnetic vibrating unit component, a difference being that it is arranged inside the casing of the mobile telephone  76001 . 
       FIG. 261A  is a perspective view of the mobile telephone  76001  of the one-hundred sixty-seventh embodiment as seen from in front, and as in the one-hundred sixty-fourth to -sixth embodiments, a large part of the front face is configured as a liquid crystal display  73205  having a touch panel function. Accordingly, electromagnetic vibrating unit components are provided at the left and right ends, respectively, of the top side of the mobile telephone  76001 . As illustrated in  FIG. 261A , however, the electromagnetic vibrating unit components do not appear in the exterior appearance. 
       FIG. 261B  is a partly enlarged sectional view of the mobile telephone  76001  as cut along a plane perpendicular to its top and side faces on the sectional plane B 2 -B 2  in  FIG. 260A , and shows in detail the structure of the electromagnetic vibrating unit component for arrangement on the top side. As is clearly shown in  FIG. 261B , in the one-hundred sixty-sixth embodiment, the voice coil bobbin  76024   k  and the yoke  76024   h  are connected together by the elastic member  76065  to constitute the electromagnetic vibrating unit. 
     The voice coil bobbin  76024   k  side is bonded to the inside of a top-side casing  76001   a  of the mobile telephone  76001 . The yoke  76024   h  side has no support, and can vibrate freely. Here, the aim of the voice coil bobbin  76024   k  side being bonded to the inside of the top-side casing  76001   a  is, since the yoke  76024   h  side has no support, the yoke  76024   h  side with a large weight is left as a freely vibrating side, to permit the reaction of the vibration of the yoke  76024   h  side to conduct, by inertia, to the top-side casing  76001   a . A corner part of the mobile telephone  76001  to which vibration is conducted in that way is brought into contact with the ear cartilage to achieve suitable cartilage conduction. In this structure, when a sound signal is fed to the voice coil  72024   m , the yoke  76024   h  side supported via the elastic member  76065  on voice coil bobbin  76024   k  is vibrated freely. 
     Also in the one-hundred sixty-seventh embodiment, between the pair of parts of the electromagnetic vibrating element which move relative to each other (the part comprising the magnet  72024   f , the central magnetic pole  72024   g , the yoke  76024   h , and the top plate  72024   j  and the part comprising the voice coil bobbin  76024   k  and the voice coil  72024   m ), the elastic member  76065  is interposed to allow their movement relative to each other, and vibration is extracted from one of the pair of parts of the electromagnetic vibrating element (in the one-hundred sixty-seventh embodiment, the part comprising the voice coil bobbin  76024   k  which receives the reaction of the free vibration of the yoke  76024   h  and the like). In the one-hundred sixty-seventh embodiment, as will be clear from  FIG. 261B , the vibration direction is perpendicular to the top side. 
     One-Hundred Sixty-Eighth Embodiment 
       FIG. 262  comprises front sectional views of a one-hundred sixty-eighth embodiment according to one aspect of the present invention, and shows the internal structures of a cartilage conduction vibration unit configured as a hearing device, more specifically as stereo earphones for mobile telephones and mobile music terminals. The overall configuration of the one-hundred sixty-eighth embodiment in  FIG. 262  is common to the one-hundred sixtieth embodiment in  FIG. 251 , and accordingly the following description focuses on the structure of the cartilage conduction vibration unit. Like the one-hundred sixty-third embodiment in  FIG. 257 , the one-hundred sixty-eighth embodiment in  FIG. 262  adopts, as a vibration source, an electromagnetic vibrating element. 
       FIG. 262A  is a front sectional view of a first specific arrangement in the one-hundred sixty-eighth embodiment. In the specific arrangement in  FIG. 262A , the cartilage conduction vibration unit  77024  is configured as an elastic body. Moreover, it has, like the cartilage conduction vibration unit  66024  in the one-hundred sixtieth embodiment in  FIG. 251 , a shape that fits in the cavum conchae of an ear. The vibration of the surface of the cartilage conduction vibration unit  77024  serving as an earpiece is conducted to the ear cartilage around the cavum conchae and the external auditory meatus opening, such as that in the tragus, via a large contact area, and achieves efficient cartilage conduction. Moreover, at the center of the cartilage conduction vibration unit  77024 , a through-hole  77024   a  is formed, and thus even with the cartilage conduction vibration unit  77024  fitted in the cavum conchae, air-conduction sound from outside can enter the external auditory meatus opening and reach the eardrum. 
     In the first specific arrangement of the one-hundred sixty-eighth embodiment in  FIG. 262A , the cartilage conduction vibration unit  77024  further has a vibration source arrangement space  77024   b , and inside it, an electromagnetic vibrating element is arranged. The vibration source arrangement space  77024   b  has no opening on the exterior surface, and is kept water-tight after assembly. The internal structure of the electromagnetic vibrating element  77024  in the first specific arrangement of the one-hundred sixty-eighth embodiment in  FIG. 262A  is common to that of the one-hundred sixty-third embodiment shown in  FIG. 257 , and accordingly for such parts as correspond to those illustrated, no new reference numerals will be assigned and no description will be repeated unless necessary. 
     In the first specific arrangement of the one-hundred sixty-eighth embodiment in  FIG. 262A , to one face of the inside of the vibration source arrangement space  77024   b , the yoke  77024   h  is bonded, and on the opposite one face, the voice coil bobbin  77024   k  is bonded. In this structure, when a sound signal is fed to the voice coil  77024   m , due to the elasticity of the cartilage conduction vibration unit  77024 , the yoke  77024   h  and the like and the voice coil bobbin  77024   k  and the like vibrate relative to each other, and the vibration conducts via the cartilage conduction vibration unit  77024 , which is an elastic body, to the ear cartilage in contact with it. 
     As described above, also in the one-hundred sixty-eighth embodiment, between the pair of parts of the electromagnetic vibrating element which move relative to each other (the part comprising the yoke  77024   h  and the like and the part comprising the voice coil bobbin  77024   k  and the like), an elastic member is interposed (the pair of parts is supported by the cartilage conduction vibration unit  77024 , which is an elastic body) to allow their movement relative to each other, and vibration is extracted from the cartilage conduction vibration unit  77024 , which is an elastic member. As will be clear from  FIG. 262A , the vibration direction in the one-hundred sixty-eighth embodiment points radially with respect to the cartilage conduction vibration unit  77024 . 
       FIG. 262B  shows a second specific arrangement in the one-hundred sixty-eighth embodiment, where, in the cartilage conduction vibration unit  78024 , which is an elastic body, a semicircular through-hole  78024   a  is provided, and in addition a vibration source arrangement space  78024   b  is provided, inside which an electromagnetic vibrating element is arranged. In the second specific arrangement, the direction of the electromagnetic vibrating element is rotated through 90 degrees compared with in the first specific arrangement in  FIG. 262A ; in other respects, the structure and workings here are basically similar to those in the first specific arrangement. 
     One-Hundred Sixty-Ninth Embodiment 
       FIG. 263  comprises front sectional views of a one-hundred sixty-ninth embodiment according to one aspect of the present invention, and shows the internal structures of a cartilage conduction vibration unit configured, like that of the one-hundred sixty-eighth embodiment in  FIG. 262 , as a hearing device, more specifically as stereo earphones for mobile telephones and mobile music terminals. The configuration of the one-hundred sixty-ninth embodiment in  FIG. 263  is basically common to the one-hundred sixty-eighth embodiment in  FIG. 262  except that, here, the cartilage conduction vibration unit is configured as a rigid body. 
       FIG. 263A  is a front sectional view of a first specific arrangement in the one-hundred sixty-ninth embodiment. In the specific arrangement in  FIG. 263A , the cartilage conduction vibration unit  79024  is configured as a rigid body. Inside the vibration source arrangement space  79024   b , an electromagnetic vibrating element is arranged, and this has a slightly different structure here to cope with the cartilage conduction vibration unit  79024  being a rigid body. Specifically, the part comprising the yoke  79024   h  and the like is supported inside a housing  79065 , which is an elastic body, and the voice coil bobbin  79024   k  is bonded to the opening of the housing  79065 . The electromagnetic vibrating element so configured is housed in the vibration source arrangement space  79024   b . In this structure, when a sound signal is fed to the voice coil  72024   m , due to the elasticity of the housing  79065 , the yoke  79024   h  and the like vibrate relative to the voice coil bobbin  79024   k  and the like, and the vibration conducts via the cartilage conduction vibration unit  79024  to the ear cartilage in contact with it. 
     As described above, also in the one-hundred sixty-ninth embodiment, between the pair of parts of the electromagnetic vibrating element which move relative to each other (the part comprising the yoke  79024   h  and the like and the part comprising the voice coil bobbin  79024   k  and the like), an elastic member (the housing  79065 ) is interposed to allow their movement relative to each other, and vibration is extracted from the cartilage conduction vibration unit  79024 . As will be clear from  FIG. 263A , also in the one-hundred sixty-ninth embodiment, the vibration direction points radially with respect to the cartilage conduction vibration unit  77024 . 
       FIG. 263B  shows a second specific arrangement in the one-hundred sixty-ninth embodiment, where, in the cartilage conduction vibration unit  80024 , which is a rigid body, a semicircular through-hole  80024   a  is provided, and in addition a vibration source arrangement space  80024   b  is provided, inside which an electromagnetic vibrating element is arranged. In the second specific arrangement, the direction of the electromagnetic vibrating element is rotated through 90 degrees compared with in the first specific arrangement in  FIG. 263A ; in other respects, the structure and workings here are basically similar to those in the first specific arrangement. 
     The features of the embodiments of the present invention described above are not limited to those embodiments; they may be adopted in any other embodiments so long as they provide their benefits. For example, in the one-hundred sixty-sixth embodiment in  FIG. 260 , instead of the yoke  75024   h  being exposed on the surface of the mobile telephone  75001  as a rigid-body cartilage conduction unit, the entire top side may be coated with a coating film such that the boundary between the cartilage conduction unit and the other part is invisible in the exterior appearance. Instead, only the part corresponding to the yoke  75024   h  may be coated with a film or a member suitable in the exterior appearance. 
     The configuration of the one-hundred sixty-fourth embodiment in  FIG. 258  has been described as an electromagnetic vibrating unit component for arrangement on a side face, and the configurations of the one-hundred sixty-sixth and -seventh embodiments have been described as electromagnetic vibrating unit components for arrangement on the top side. However, unlike the one-hundred sixty-fifth embodiment in  FIG. 259 , the one-hundred sixty-fourth, -sixth, and -seventh embodiments are not configurations peculiar to the respective arrangement positions; thus, contrary to the above description, the configurations of the one-hundred sixty-sixth and -seventh embodiments may be used in electromagnetic vibrating unit components for arrangement on a side face, or the configuration of the one-hundred sixty-fourth embodiment may be used in an electromagnetic vibrating unit component for arrangement on the top side. 
     Furthermore, in a case where, as in the one-hundred sixty-seventh embodiment in  FIG. 261 , an electromagnetic vibrating unit component is provided on the inside of the top side of a mobile telephone, instead of it being provided at each of the left and right ends as in the one-hundred sixty-seventh embodiment, one electromagnetic vibrating unit component may be provided at the center of the top side so that the vibration that conducts to the top frame conducts to the cartilage conduction units in the left and right corners. 
     One-Hundred Seventieth Embodiment 
       FIG. 264  comprises a sectional view related to a one-hundred seventieth embodiment according to one aspect of the present invention and diagrams illustrating how it is worn on an ear, the embodiment being configured as a stereo headset  81081 .  FIG. 264A  is a sectional view showing the overall structure of the stereo headset  81081 , and as illustrated, the stereo headset  81081  includes a right-ear unit  81082  and a left-ear unit  81084  supported on a head arm part  81081   a . Furthermore, in a top-of-head part of the head arm part  81081   a , there is provided a central unit  81086  which includes a headset control unit  81039 , an antenna  81045  for local communication, and the like. 
     The right-ear unit  81082  includes, among others, a right microphone  81038  chiefly for detection of outside noise, and this drives a right cartilage conduction unit  81024  configured as an elastic body. Likewise, the left-ear unit  81084  includes, among others, a left microphone  81039  chiefly for detection of outside noise, and this drives a left cartilage conduction unit  81026  configured as an elastic body. The left-ear unit  81084  supports a sound microphone  81023  via a microphone arm. 
     Structured as described above, the stereo headset  81081  of the one-hundred seventieth embodiment permits a person (for example, a store employee) who wears it to perform wireless conversation with another stereo headset (worn by another store employee) within a local area (for example, inside an eating place). As will be described in detail below, the right and Oilage conduction unit  81024  and  81026  are provided with through-holes  81024   a  and  81026   a  respectively so that, even when the stereo headset  81081  is worn, sound from outside (for example, when used in an eating place or the like, the voice of a customer calling for attention) can be heard and the direction from which it comes can be recognized. 
       FIG. 264B  is a view of the right ear  28  as seen from in front of the face, and illustrates the relationship of the right ear  28  with the right cartilage conduction unit  81024  when the stereo headset  81081  is worn. The right cartilage conduction unit  81024  is worn by being slid into the cavum conchae  28   e  from in front of the face. The cavum conchae  28   e  is open frontward except for the pliable tragus  32  protruding, and thus the right cartilage conduction unit  81024  can fit into it smoothly. At this time, the tragus  32  bends rearward of the face and moves in a direction in which it closes the entrance of the external auditory meatus; to prevent this and keep the entrance of the external auditory meatus open, the right cartilage conduction unit  81024  has a concavity  81024   c  formed in it at a position at which it makes contact with the tragus  32 . Thus, once the right cartilage conduction unit  81024  fits in the cavum conchae  28   e , the tragus  32  by its elasticity restores its original shape in the concavity  81024   c , and ensures that the entrance to the external auditory meatus is open. When the tragus  32  restores its original shape in the concavity  81024   c , it fits the inner face of the concavity  81024   c  and maintains a satisfactory contact relationship. While the size, shape, and position of the tragus  32  vary among individuals, by forming the concavity  81024   c  slightly smaller than the average-sized tragus  32 , it is possible to achieve contact with the inner face of the concavity  81024   c  and keep open the entrance of the external auditory meatus. Also the other part of the right cartilage conduction unit  81024  fitted in the cavum conchae  28   e  makes contact with the cartilage at the entrance of the external auditory meatus over a large area, and this helps achieve satisfactory cartilage conduction. 
       FIG. 264C  is a view of the right ear  28  as seen from the side of the face, and supplements the description given above with reference to  FIG. 264B . As is clearly shown in  FIG. 264C , of the cartilage conduction unit  81024 , a part closer to the front of the face fits in the cavum conchae  28   e . At this time, the tragus  32  restores its original shape in the concavity  81024   c , and ensures that the entrance of the external auditory meatus is open. Moreover, as is clearly shown in  FIG. 264C , the through-hole  81024   a  in the one-hundred seventieth embodiment is in a crescent shape as illustrated to ensure suitable contact of the concavity  81024   c  with the tragus  32 . 
     Moreover, as clearly shown in  FIG. 264C , in the cartilage conduction unit  81024 , a sheath-form space  81024   b  is provided, and at its tragus  32  side end, a piezoelectric bimorph element  81025  is held with its one end stuck in. Thus, the other end of the piezoelectric bimorph element  81025  vibrates freely in the sheath-form space  81024   b , and the vibration as its reaction conducts to the cartilage conduction unit  81024 . The cartilage conduction unit  81024  is configured as an elastic body, and has an acoustic impedance different from that of the arm part  81081   a ; this suppresses conduction of vibration to the arm part  81081   a . This principle is common to, for example, the one-hundred ninth embodiment in  FIG. 182 . This suppresses generation of air-conduction sound, and conduction of vibration to the variable equalizer  57038  and the like, resulting from vibration of the arm part  81081   a.    
       FIG. 265  is a block diagram of the one-hundred seventieth embodiment in  FIG. 264 , and illustrates wireless conversation in a local area between a plurality of stereo headsets. In  FIG. 265 , such parts as find their counterparts in  FIG. 264  are identified by the same reference numerals, and no overlapping description will be repeated unless necessary. In  FIG. 265 , two stereo headsets are shown as an A headset  81081 A and a B headset  81081 B, and parts belonging to them are distinguished by identifying them by the same reference numerals as in  FIG. 264  but suffixed with A and B respectively. 
     The configuration of the A headset  81081 A in  FIG. 265  basically corresponds to what is shown in  FIG. 264 . However, in  FIG. 265 , for the sake of functional illustration, an A right cartilage conduction unit  81024 A is shown inside the block of an A right-ear unit  81082 A (in  FIG. 264 , to show its shape, the right cartilage conduction unit  81024  is illustrated outside the right-ear unit  81082 ). The same applies to the A left cartilage conduction unit  81026 A. In the illustrated case, the A headset  81081 A functions as a master device, which will be described later, and can engage in simultaneous conversation with any stereo headset other than the B headset  81081 B. The A and B headsets  81081 A and  81081 B have the same configuration, and depending on settings, the B headset  81081 B can also function as a master device. 
     Next, with reference to  FIG. 265 , based on the B headset  81081 B, the block diagram of a stereo headset will be described in detail. The B headset  81081 B is controlled by a B headset control unit  81039 B provided in a B central unit  81086 B. A storage unit  81037  stores programs and data necessary for the B headset control unit  81039 B to function. The B headset control unit  81039 B, as necessary, switches functions according to operation on an operation unit  81009 , and also controls a display unit  81205 . A power source unit  81048  supplies the entire B headset  81081 B with electric power. 
     A sound processing unit  81040  basically processes the wearer&#39;s sound collected by a B sound microphone  81023 B, and transmits it from a local communication unit  81046  via a B antenna  81045 B to the A headset  81081 A. Moreover, the sound processing unit  81040  basically, based on a stereo sound signal from the A headset  81081 A as received by the local communication unit  81046  via the B antenna  81045 B, vibrates a B right cartilage conduction unit  81024 B and a B left cartilage conduction unit  81026 B via a right drive unit  81035  and a left drive unit  81036  respectively. 
     At this time, the sound processing unit  81040  inverts the phases of ambient noise signals collected from a B right microphone  81038 B and a B left microphone  81039 B, and mixes the resulting signals with the sound signals to the right and left drive units  81035  and  81036  so as to be superimposed on the driving of the B right and left cartilage conduction units  81024 B and  81026 B. Thus, the direct air-conduction sound of ambient noise that has entered the external auditory meatus through the through-holes  81024   a  and  81026   a  (see  FIG. 264 ) is cancelled inside the external auditory meatus by the phase-inverted cartilage air-conduction sound of ambient noise produced inside the external auditory meatus by cartilage conduction. 
     However, the air-conduction sound that enters the external auditory meatus from the outside through the through-holes  81024   a  and  81026   a  contains a necessary sound component such as the voice of a customer making an order in a store. Here, ambient noise is reflected irregularly in the ambience, and is considered to be collected by the B right and left microphones  81038 B and  81039 B with largely equal levels. By contrast, the voice from a customer comes from one direction, and is considered to be collected by the B right and left microphones  81038 B and  81039 B with different levels. This is exploited by taking the difference between the levels collected by the B right and left microphones  81038 B and  81039 B, and based on whether the difference is positive or negative, for whichever of the B right and left microphones  81038 B and  81039 B yields a positive difference, the difference signal is subtracted from the sound signal collected by the microphone to eliminate the inverted signal. In this way, from the phase-inverted cartilage air-conduction sound produced in the external auditory meatus of that ear which has collected the customer&#39;s voice with the higher level, the differential sound component is eliminated, and the necessary voice of the customer is not cancelled. On the other hand, for whichever yields a negative difference, since this is not the side from which the voice of the customer comes, the inverted signal of the sound signal collected by the microphone is created. 
     The sound collected by the B sound microphone  81023 B contains, in addition to the wearer&#39;s sound, ambient noise. By contrast, the B right and left microphones  81038 B and  81039 B are far away from the wearer&#39;s mouth, and are considered to collect chiefly noise. Accordingly, by subtracting the sound signals collected by the B right and left microphones  81038 B and  81039 B from the sound signal collected by the B sound microphone  81023 B, the noise component is canceled, and the remaining sound signal of the wearer is transmitted. 
     In the B central unit  81086 B, there are provided a GPS  81038  and a local position sensor  81042  based on a position detection system provided within a communicable area. Based on these sensors, the B headset control unit  81039 B transmits the wearer&#39;s position from the local communication unit  81046  via the B antenna  81045 B to the A headset  81081 A. In the B central unit  81086 B, there is further provided a direction sensor  81049 . Based on the direction sensor  81049 , the B headset control unit  81039 B transmits the rotation position of the wearer&#39;s head from the local communication unit  81046  via the B antenna  81045 B to the A headset  81081 A. 
     The A headset  81081 A likewise receives the wearer&#39;s position and the rotation position of the wearer&#39;s head from each of a plurality of stereo headsets with which it is paired. First, based on the position signals of the respective wearers, the A headset  81081 A maps the plurality of stereo headsets with which it is paired on a map of the area. Then, based on the mapping, the A headset  81081 A computes, for each wearer, the direction from which voice comes when the wearer is addressed by another wearer. The A headset  81081 A also corrects the direction from which voice is heard, because it rotates relatively about the wearer as the wearer&#39;s head rotates. 
     As the master device, the A headset  81081 A relays monitoring sound of simultaneous conversation to each slave device, and when relaying sound from another slave device to a particular slave device, adjusts the left-right sound volume balance of the stereo sound and performs mixing for each of the other slave devices based on the computed voice direction mentioned above. Thus, when monitoring the sound signal from another slave device, the particular slave device can hear, in a stereo sound filed, the sound from the other slave device separately as if coming from the place where its wearer is actually located. As the master device, the A headset  81081 A performs similar processing for and relays monitoring sound to each slave device. 
     The primary purpose of the above processing is, during simultaneous monitoring of sounds from a plurality of slave devices, to separate them from each other by changing the directions from which they are heard by use of a stereo sound field. It is the secondary purpose to make sound from a slave device heard from the direction in which it is actually located. Accordingly, in a case where no strictness is required in the secondary purpose, it suffices simply to change the left-right sound volume balance for each slave device and, as for the direction, previously assign slave devices predetermined directions respectively so as to differentiate the left-right sound volume balance irrespective of their actual positions. 
       FIG. 266  is a block diagram showing in detail the sound processing unit  81040  in  FIG. 265 . Such parts as appear also in  FIG. 265  are identified by the same reference numerals, and no overlapping description will be repeated unless necessary. While the configuration in  FIG. 265  is the details of the sound processing unit  81040  illustrated as the one provided in the B headset  81081 B in  FIG. 265 , this configuration is common to the A headset  81081 A, and therefore, to avoid complexity, the suffix “B” is omitted from the reference numerals. 
     The sound processing unit  81040  subtracts, in a subtractor  81040   a , the sound signals collected by the right and left microphones  81038  and  81039  from the sound signal collected by the sound microphone  81023 , and transmits the result from the local communication unit  81046  to another stereo headset. The purpose is, as mentioned above, to subtract from the ambient noise contained in the sound collected by the sound microphone  81023  the sound signals of the right and left microphones  81038  and  81039  which collect similar ambient noise, thereby to obtain the sound signal of the wearer containing less outside noise. 
     When driving the right drive unit  81035  based on the right sound signal from another stereo headset as received by the local communication unit  81046 , the sound processing unit  81040  inverts, in the phase inverter  81040   b , the ambience noise signal collected by the right microphone  81038 , and performs mixing in a right mixer  81040   c . At that time, in a difference extractor  81040   d , the sound signal of the left microphone  81039  is subtracted from the sound signal of the right microphone  81038 , and in a sign discriminator  81040   e , whether the difference is positive or negative is discriminated. 
     Here, if the difference is positive, it means that the sound signal of the right microphone  81038  contains a sound component with a high sound volume (not a noise component irregularly reflected in the ambience but an air-conduction sound component generated from a particular sound source on the right side, such as the voice of a customer). Accordingly, in that case, under the control of the sign discriminator  81040   e , a switch  81040   f  is turned on so that, in a subtractor  81040   g , the difference is subtracted from the sound signal collected by the right microphone  81038 . As a result, the difference is eliminated from the inverted signal, and the noise component that is even left-to-right is cancelled in the external auditory meatus, but the sound component coming from the right side is not canceled. On the other hand, if the difference discriminated by the sign discriminator  81040   e  is negative, or no difference is discriminated, it means that no particular sound comes from the right side, and thus, under the control of the sign discriminator  81040   e , the switch  81040   f  is turned off. Accordingly, no subtraction of a difference is performed in the sign discriminator  81040   e , and the sound signal collected by the right microphone  81038 , as it is, is inverted. 
     The functions of the blocks  81040   h  to  81040   k  related to the driving of the left drive unit  81036  shown in  FIG. 266  can be understood in a similar manner as the driving of the right drive unit  81035  described above, and therefore no overlapping description will be repeated. As described above, in the difference extractor  81040   d , the sound signal of the left microphone  81039  is subtracted from the sound signal of the right microphone  81038 ; thus, when the left microphone  81039  contains a component with a particularly high sound volume, the difference discriminated by the sign discriminator  81040   e  is negative; at this time, a switch  81040   j  is turned on. On the other hand, if the difference discriminated by the sign discriminator  81040   e  is positive, or no difference is discriminated, the switch  81040   j  is off. 
     The function described above presupposes that air-conduction sound with a particularly high sound volume occurs temporarily from either the right or left side and that the air-conduction sound is the voice of a person needed as information. However, known noise with a high sound volume may occur continuously from either the right or left side. In such a case, the operation unit  81009  issues, via the headset control unit  81039 , an instruction to top the function of the sign discriminator  81040   e . Then, even if there is a difference between the sound volumes collected by the right and left microphones  81038  and  81039 , all noise is canceled. 
       FIG. 267  is a basic flow chart related to the operation of the A or B headset control unit  81039 A or  81039 B. For simplicity&#39;s sake, the flow in  FIG. 267  illustrates, chiefly, extracted operations focused on functions related to the monitoring of multi-device simultaneous conversation by a plurality of stereo headsets, and as to ordinary conversation between headsets, there also exist operations of the A or B headset control unit  81039 A or  81039 B that are not shown in the flow in  FIG. 267 . 
     The flow in  FIG. 267  starts when the main power to the headset is turned on by operation on the operation unit  81009 . First, at step S 1102 , the stereo headset is set as a slave device by default, and the flow proceeds to step S 1104 . At step S 1104 , it is checked whether or not a new pairing operation with another stereo headset has been done, and if new pairing has been done, the flow proceeds to step S 1106 , where pairing processing with the relevant unit is performed, the flow then proceeding to step S 1108 . On the other hand, if, at step S 1104 , no new pairing has been done, the flow proceeds directly to step S 1108 . 
     At step S 1108 , it is checked whether or not a multi-device simultaneous conversation mode for three or more stereo headsets has been set. If in the multi-device simultaneous conversation mode, then, at step S 1110 , it is checked whether or not the stereo headset in question has been set as a master device. If a master device setting has been made, the flow proceeds to step S 1112 , where master device processing is performed, and the flow then proceeds to step S 1116 . On the other hand, if no master device setting has been made, the flow proceeds to step S 1114 , where slave device processing is performed, and the flow then proceeds to step S 1116 . If, at step S 1118 , not in the multi-device simultaneous conversation mode, then the flow proceeds to step S 1118 , where a one-to-one conversation mode is set, the flow then proceeding to step S 1116 . 
     At step S 1116 , an instruction to start talk-reception or, if talk-reception has already been started, an instruction to continue it is issued, and then the flow proceed to step S 1120 . At step S 1120 , it is checked whether or not a talk-originating operation has been done, and if such an operation has been done, then, at step S 1122 , a partner device to which to originate a talk is specified, the flow then proceeding to step S 1124 , where a talk-enabled state is set, the flow then proceeding to step S 1126 . At step S 1126 , it is checked whether or not the talk-originating operation has been canceled. If it has not been cancelled, the flow returns to step S 1124 . Until, at step  1126 , the talk-originating operation is detected having been canceled, steps S 1124  and S 1126  are repeated. Then, when, at step S 1126 , the talk-originating operation is detected having been canceled, the flow proceeds to step S 1128 . On the other hand, if, at step S 1120 , no talk-originating operation is detected, the flow proceeds directly to step S 1128 . At step S 1128 , it is checked whether or not the main power has been turned off, and if the main power is not detected having been turned off, the flow returns to step S 1104 . Thereafter, until, at step S 1128 , the main power is detected having been turned off, steps S 1104  through S 1128  are repeated to continue the talk-receiving state while coping with various changes in situation. 
       FIG. 268  is a flow chart showing the details of the master-device processing at step S 1112  in  FIG. 267 . When the flow starts, at step S 1132 , all slave devices in a paired state are confirmed. Then, at step S 1134 , it is checked whether or not information on a slave device has been newly received or whether or not information on a slave device has been changed. If there is any relevant slave device, the flow proceed to step S 1136 , where what is stored for that slave device as slave device-by-slave device in-area position sensor information is updated, and the flow proceed to step S 1138 . Here, to “update” includes to “store newly.” 
     At step S 1138 , the GPS information of the relevant slave device is updated, and furthermore, at step S 1140 , the direction sensor information of the relevant slave device is updated. Subsequently, at step S 1142 , based on the updated information, mapping computation processing is performed as to the position of each slave device, and the flow proceeds to step S 1144 . Here, the “mapping computation” at step S 1142  includes renewed mapping computation as well as computation performed to correct existing mapping computation results based on changes in the position information of each slave device. At step S 1144 , based on the direction sensor information and mapping computation from each slave device, computation processing as to the directions of the other devices as seen from each slave device is performed, and the flow proceeds to step S 1146 . Here, the “other device computation” at step S 1144  includes renewed computation of the directions of the other devices based on the direction sensor information of each slave device as well as correcting computation based on changes in the direction of the head of the wearer of each slave device. Also if, at step S 1134 , there is neither new reception of, or a change in, slave-device information, the flow proceeds to step S 1146 . 
     At step S 1146 , it is checked whether or not the number of slave devices paired with the master device is one. If the number is not one, each slave device is in a state where it can monitor sound from a plurality of other stereo headsets including the master device, and therefore separation of monitoring sound by use of a stereo sound field is useful. Accordingly, the flow proceeds to step S 1148 , where it is checked whether or not the mapping position computation at step S 1142  and the other-device direction computation at step S 1144  have been successful. If those computations have been successful, the flow proceed to step S 1150 , where processing for setting the left-right balance in the stereo sound field of the monitoring sound from the other devices to be transmitted to a particular slave device. This processing is performed for the monitoring sound from all the other devices on a slave device-by-slave device basis. 
     Subsequently, at step S 1152 , as to a particular slave device, processing for mixing the monitoring sound from the other devices is performed, and then the flow proceed to step S 1154 , where an instruction to start transmission of monitoring sound on a slave device-by-slave device basis, or, if it has already been started, an instruction to continue it is issued, and then the flow ends. 
     On the other hand, if, at step S 1146 , it is confirmed that the number of slave devices paired with the master device is one, then only the sound from the master device has to be transmitted; accordingly, the flow proceed to step S 1156 , where the left-right balance of the sound to be transmitted is made even, and the flow then proceeds to step S 1154 . If, at step S 1148 , the position/direction computations are not confirmed to have been successful, then the flow proceeds to step S 1158 . Of the purposes of changing the left-right balance of the sounds from a plurality of other devices to change the directions from which they are heard, as mentioned above, the primary one is to separate the plurality of sounds from each other by use of a stereo sound field. Accordingly, if, even when the direction computation fails, it is possible to separate a plurality of sounds by use of a stereo sound field, the just-mentioned first purpose is fulfilled. Accordingly, if, at step S 1148 , the position/direction computations are not confirmed to have been successful, the left-right balance of the plurality of sounds to be mixed is differentiated as predetermined different balances that are previously assigned to individual slave devices respectively, and the flow then proceeds to step S 1154 . 
       FIG. 269  is a flow chart showing the details of the slave-device processing at step S 1114  in  FIG. 267 . When the flow starts, at step S 1162 , the pairing state with the master device is checked and, if no pairing has been done, pairing is done anew, and the flow proceeds to step S 1164 . At step S 1164 , whether or not the pairing is new is checked, and if it is not new, the flow proceeds to step S 1166 , where whether or not there is any movement is checked based on the local position sensor  81042  and the GPS sensor  81038 . If there is any movement, the flow proceeds to step S 1168 . If, at step S 1164 , the pairing is confirmed to be new, the flow proceeds immediately to step S 1168 . At step S 1168 , the information detected by the local position sensor  81042  is transmitted, and then the flow proceeds to step S 1170 , where the information detected by the GPS sensor  81038  is transmitted, the flow then proceeding to step S 1172 . On the other hand, if, at step S 1166 , no movement is detected, the flow proceeds immediately to step S 1172 . 
     At step S 1172 , whether or not there is any head rotation is checked based on the direction sensor  81049 . If there is any rotation, the flow proceeds to step S 1174 , where the information detected by the direction sensor  81049  is transmitted, and the flow ends. On the other hand, if, at step S 1172 , no head rotation is detected, the flow ends immediately. 
     As described above, when a stereo headset is set as a slave device, the movement of the wearer and the rotation of the head are transmitted continually to the master device to notify it of the relationship of the master device with the other slave devices paired with it and the directions of the heads of their wearers so as to keep a state where the monitoring sounds of the individual slave devices transmitted in a mixed form from the master device are heard separately from each other in a stereo sound field as if actually coming from the other slave devices. 
     The various features of the embodiments described above are not limited to those embodiments, and may be adopted in any other embodiments so long as they provide their benefits. For example, as mentioned above, the primary purpose of changing the directions of the monitoring sounds heard from individual slave devices by use of a stereo sound field is to separate the monitoring sounds of the individual slave devices from each other. Accordingly, the one-hundred seventieth embodiment may be simplified by omitting the communication with the master device as to slave device positions and head rotations and omitting steps S 1134  through S 1144 , S 1150 , and S 1152  in  FIG. 268  so that, when the number of slave devices is not one, everything is processed at step S 1158 . 
     One-Hundred Seventy-First Embodiment 
       FIG. 270  is a side view related to a one-hundred seventy-first embodiment according to one aspect of the present invention, which is configured as a cycling helmet  82081  having a stereo headphone function. A helmet part  82081   a  includes a stereo sound source unit  82084  which provides a stereo sound source, a camera unit  82055  which functions as an action camera, a mobile telephone communication unit  82047 , and an antenna  82045  for it. The helmet part  82081   a  further includes a control unit  82039  which controls the entire cycling helmet  82081  and a power source unit  82048  which supplies the entire cycling helmet  82081  with electric power. The power source unit  82048  includes a rechargeable battery which is charged by an external power source that is connected to charge contacts  82014 . As will be described later, the helmet part  82081   a  further includes other related structures. 
     The helmet part  82081   a  is fitted with a chin strap part  82081   b , which is provided with a vibration source  82025   a  for the tragus and a vibration source  82025   b  for the base of the ear, which vibrate according to a sound signal from the stereo sound source unit  82084 . As will be clear from  FIG. 270 , the chin strap part  82081   b  is Y-shaped so that, when the helmet part  82081   a  is worn and the chin strap part  82081   b  is tightened, the chin strap part  82081   b  passes along the front and rear sides of the ear (in the illustrated example, the left ear  30 ). Thus, the vibration source  82025   a  makes contact with the tragus  32  and the vibration source  82025   b  with the outside of the cartilage in the base of the ear, each producing satisfactory cartilage conduction. 
     The details of cartilage conduction resulting from contact with the tragus are common to the one-hundred seventieth embodiment in  FIG. 264  and the like, and the details of cartilage conduction from the outside of the cartilage in the base of the ear are common to the eighty-ninth embodiment in  FIG. 139  and the like. The one-hundred seventy-first embodiment in  FIG. 270 , in that it uses both cartilage conduction resulting from contact with the tragus and cartilage conduction from the outside of the cartilage in the base of the ear, is common to the ninety-ninth embodiment in  FIG. 156 . However, there are differences in that, here, the Y-shaped chin strap part  82081   b  is used to achieve contact with the ear cartilage by holding the ear from in front and behind and that separate vibration sources  82025   a  and  82025   b  for the tragus and the base of the ear respectively are provided so that, as necessary, they can be fed with differently equalized sound source signals. 
     What is important in the implementation as a cycling helmet  82081  in the one-hundred seventy-first embodiment is, as will be clear from  FIG. 270 , that the external auditory meatus opening  30   a  is open and thus sound from the outside world such as vehicle horns can be heard with no hindrance. Moreover, as will be seen from  FIG. 270 , from the exterior appearance, it is obvious that the external auditory meatus  30   a  opening is open, and this helps avoid needless troubles arising from being misunderstood as violating road traffic law prohibiting riding bicycles wearing earphones and the like. While  FIG. 270  illustrates only the surroundings of the left ear, the configuration around the right ear is similar. Specifically, also the right ear is in a condition where satisfactory cartilage conduction is produced. In cartilage conduction, sound is heard via the eardrum, and thus the sound source can be listened to in a stereo sound field. Moreover, in listening to a stereo sound source, the external auditory meatus of the right and left ears are open in left-to-right symmetry, and thus the direction of sound from the outside world such as vehicle horns can be recognized correctly. This means that the present invention provides far higher effects in sound source listening and road safety compared with conventional bicycle riding with an earphone inserted in one ear only to leave the other ear open to hear sound from the outside world. 
     In the one-hundred seventy-first embodiment, as will be clear from  FIG. 270 , at the position where a chin part  82082  of the chin strap part  82081   b  in a lower part of it touches the throat, a bone conduction microphone  82023  is provided. In a lowest part of the chin part  82082 , a chin switch  82010  is arranged, by which the cycling helmet  82081  is operated according to the motion of the chin during bicycle riding. For example, opening the mouth and lowering the chin increases the tension of the chin strap part  82081   b , and by detecting this state being kept for a predetermined time, an operation for accepting a call received by a mobile telephone is performed. A ringtone can be heard by cartilage conduction, and likewise a call accepting tone of the chin switch  82010  can be heard by cartilage conduction. The chin switch  82010  is so configured as to allow starting and stopping listening to a sound source signal, scrolling to select tracks, adjusting sound volume, recording an action movie by the camera unit  82055 , and the like according to the length, the number of times, the pattern, and the like that the mouth is opened. 
       FIG. 271  is an overall block diagram of the cycling helmet  82081  in the one-hundred seventy-first embodiment. Such parts as appear also in  FIG. 270  are identified by the same reference numerals, and no overlapping description will be repeated unless necessary. To the control unit  82039  provided in the helmet part  82081   a , an operation unit  82009  and a display unit  82205  are connected to allow basic settings and the like to be made when the cycling helmet  82081  is removed. The camera unit  82055 , as an action camera, continuously shoots the forward view during bicycle riding, and stores in the storage unit  82037  a moving image having undergone processing by an image processing unit  82053 . In this recording, except for parts for which an operation to store them as an action camera movie is performed, the existing images keep being updated from the oldest one within the set capacity. The latest recorded image is used as drive recorder evidence in the event of an accident. The storage unit  82037  not only records images as just described, but also stores programs, temporary, data and the like necessary for the control unit  82039  to function. 
     Under the control of the control unit  82039 , the sound processing unit  82040  outputs the stereo sound source data of the stereo sound source unit  82084  to offer it for listening. The sound processing unit  82040  also outputs, for cartilage conduction, the sound of a communication partner received by the mobile telephone communication unit  82047 , and receives the wearer&#39;s sound collected by the bone conduction microphone  82023 . The received sound is transmitted from the mobile telephone communication unit  82047  via the antenna  82045  to the communication partner. Thus, the cycling helmet  82081  of the one-hundred seventy-first embodiment serves also as a mobile telephone in the form of a cycling helmet. 
     In  FIG. 271 , the vibration sources  82025   a  and  82025   b  illustrated in  FIG. 270 , the former to touch the tragus and the latter to touch the outside of the cartilage in the base of the ear, are illustrated as a left cartilage conduction unit  82026 . Likewise, a right cartilage conduction unit  82024  is illustrated which includes a vibration source  82025   c  for the tragus and a vibration source  82025   d  for the outside of the cartilage in the base of the ear. As mentioned previously, the left- and right-ear cartilage conduction vibration units  82026  and  82024  are provided in left-to-right symmetry, the left-right balance of the stereo sound source is even, and the external auditory meatus of the right and left ears are open in left-to-right symmetry; thus, the direction of sound from the outside world such as vehicle horns can be recognized correctly. As illustrated, to the vibration sources  82025   a ,  82025   b ,  82025   c , and  82025   d , sound source signals are fed across separate channels respectively from the sound processing unit  81040 . 
       FIG. 272  is a system concept diagram showing the cycling helmet  82081  of the one-hundred seventy-first embodiment along with a power-assisted bicycle  82002 . Such parts as appear also in  FIG. 270 or 271  are identified by the same reference numerals, and no overlapping description will be repeated unless necessary. The power-assisted bicycle  82002  includes a removably-mounted assist rechargeable battery  82008  which supplies energy to an assist motor. It also includes a wheel generator  82006  which generates electric power as a wheel rotates so that, via a cable  82041 , a night lamp  82004  is supplied with energy. 
     The wheel generator  82006  is connected to the night lamp  82004 , in general, directly but, in the one-hundred seventy-first embodiment, across the cable  82041  via a control box  82010 . The control box  82010  turns on and off the current supplied from the wheel generator  82006  so that the night lamp  82004  periodically varies its brightness (as by blinking) with a particular pattern recognized as signifying cartilage conduction. Thus, in encounter with traffic policing and the like, it is possible to avoid needless troubles arising from being misunderstood as violating road traffic law prohibiting riding bicycles wearing earphones and the like. On the other hand, during the day, by riding a bicycle with a symbol  82005  recognized as signifying cartilage conduction affixed to the surface of the night lamp  82004  or anywhere else conspicuous, it is possible to avoid needless troubles arising from being misunderstood as violating road traffic law prohibiting riding bicycles wearing earphones and the like. The particular brightness varying pattern of the night lamp  82004  and the symbol mark mentioned above serve as an notifying means for avoiding misunderstanding, and recognition of the significances of such notifying means can be achieved, like the significances of the colors of the traffic signal and other public symbols, by the strength of their own power to suggest what they signify and by making them universally known through publicity and public authentication. 
     The control box  82010  also supplies electric power to the charge contacts  82014  of the cycling helmet  82081  via the cable  82041  connected to charge contacts  82010   a . As a power source, the wheel generator  82006  or the assist rechargeable battery  82008  can be used. 
     In  FIG. 272 , the cables  82041  are illustrated as if unstably isolated from the structure of the bicycle to clearly show interconnections for convenience&#39;s sake; in practice, the cables  82041  between the control box  82010  at one end and the wheel generator  82006 , the assist rechargeable battery  82008 , and the night lamp  82004  at the other end are laid inside or along the structure of the bicycle. 
       FIG. 273  is a system block diagram corresponding to the one-hundred seventy-first embodiment shown in  FIG. 272 . Such parts as appear also in  FIGS. 271 and 272  are identified by the same reference numerals, and no overlapping description will be repeated unless necessary. As described above, to the charge contacts  82014  of the cycling helmet  82081 , electric power is supplied from the control box  82010 , so that a rechargeable battery  82048   a  in the power source unit  82048  is charged. Moreover, as described above, one power source for that is the wheel generator  82006 , and when a switch  82010   b  is closed manually, electric power is supplied via the charge contacts  82010   a  to the charge contacts  82014 . Another power source for charging the rechargeable battery  82048   a  is the assist rechargeable battery  82008 , and when a switch  82010   c  is closed manually, electric power is supplied likewise via the charge contacts  82010   a  to the charge contacts  82014 . 
     During the day, with a switch  82010   d  left open manually, even when the wheel generator  82006  generates electric power, the generated electric power is not supplied to the night lamp  82004  but is used exclusively to charge the rechargeable battery  82048   a . On the other hand, during the night, with the switch  82010   d  closed manually, electric power is supplied to the night lamp  82004  via a lighting pattern conversion unit  82010   e . The lighting pattern conversion unit  82010   e  has a switching function for automatically turning the current supplied from the wheel generator  82006  on and off periodically with a predetermined pattern, and makes the night lamp  82004  blink with the above-mentioned particular blinking pattern. The lighting pattern conversion unit  82010   e  may be so configured as to automatically vary the magnitude of the current supplied to the night lamp  82004  with a predetermined pattern. 
       FIG. 274  comprises side views of modified examples of the one-hundred seventy-first embodiment shown in  FIGS. 270 to 273 , and shows another embodiment for avoiding needless troubles arising from being misunderstood as violating road traffic law prohibiting riding bicycles wearing earphones and the like in traffic policing and the like. Such parts as appear also in  FIGS. 270 and 273  are identified by the same reference numerals, and no overlapping description will be repeated unless necessary. 
       FIG. 274A  shows an example where the cycling helmet  82081  is used in combination with a sound-transmitting warm ear pad  82013  provided with a symbol  82007  recognized as signifying cartilage conduction. When, as in  FIG. 270 , no warm ear pad is used, it is obvious from the external appearance that the external auditory meatus entrance opening  30   a  is open. By contrast, when, as in  FIG. 274 , the warm ear pad  82013  is attached, the ear is hidden, and thus despite transmissivity to sound, it cannot be recognized from the external appearance whether or not the external auditory meatus entrance  30   a  is open. To cope with that, in  FIG. 274A , the sound-transmitting warm ear pad  82013  itself is provided with the symbol  82007  which is recognized as signifying cartilage conduction. By arranging, in this way, the symbol  82007  in a part that attracts most attention from the viewpoint of traffic policing, it is possible to effectively avoid needless troubles arising from misunderstanding. The symbol  82007  bears a design of the acronym “CC” of “cartilage conduction” in the shape of an ear, and is one example of significance suggestion for publicly notifying the closed state of the external auditory meatus. 
       FIG. 274B  shows an example where the helmet part  82081   a  of the cycling helmet  82081  is provided with a symbol  82011  recognized as signifying cartilage conduction. In  FIG. 274B , although it is obvious from the exterior appearance that the external auditory meatus entrance opening  30   a  is open, for easy visual recognition from a distance of the fact that cartilage conduction is adopted with the external auditory meatus open, in a large-are part of the helmet part  82081   a , the symbol  82011  that is recognized as signifying cartilage conduction is provided. By arranging, in this way, the easily visible symbol  82011  in a part that attracts most attention from the viewpoint of traffic policing, it is possible to effectively avoid needless troubles arising from misunderstanding. The symbol  82011  is a design of the principle of “cartilage conduction” in which air-conduction sound generated from a cartilage conducts to the eardrum, and is another example of significance suggestion for publicly notifying the closed state of the external auditory meatus. This design is adopted also as the symbol  82005  for the power-assisted bicycle  82002  in  FIG. 272 . 
     The various features of the embodiments described above are not limited to those embodiments, and may be adopted in any other embodiments so long as they provide their benefits. For example, although the cycling helmet  82081  in the one-hundred seventy-first embodiment in  FIG. 274  is configured as a mobile telephone, this is not meant as any limitation. For example, the mobile telephone communication unit  82047  in the cycling helmet  82081  may be configured as a near-field communication unit in the one-hundred thirty-fifth embodiment in  FIG. 220 , in which case the cycling helmet  82081  serves as a headset that is linked with a common mobile telephone by near-field wireless communication. 
     Although the cycling helmet  82081  in the one-hundred seventy-first embodiment shown in  FIGS. 270 to 274  has a Y-shaped chin strap part  82081   b  which holds an ear from opposite sides and which is provided with a vibration source  82025   a  in contact with the tragus  32  and a vibration source  82025   b  in contact with the outside of the cartilage in the base of the ear, this is not meant to limit the implementation of the present invention. For example, in a case where the chin strap is so configured as not to branch but to pass along the front side of the ear to reach the chin, only a vibration source  82025   a  in contact with the tragus  32  may be provided. On the other hand, in a case where the chin strap is so configured as not to branch but to pass along the rear side of the ear to reach the chin, only a vibration source  82025   b  in contact with the outside of the cartilage in the base of the ear may be provided. Also in these cases, contact with the ear cartilage provides satisfactory cartilage conduction, and it is obvious from the exterior appearance that the external auditory meatus opening  30   a  is open; thus it is possible to avoid needless troubles arising from being misunderstood as violating road traffic law prohibiting riding bicycles wearing earphones and the like 
     In the power-assisted bicycle  82002  shown in  FIG. 272 , when the cycling helmet  82081  is charged from the wheel generator  82006  or the assist rechargeable battery  82008 , the charge contacts  82010   a  on the control box  82010  are shared. This is not meant to limit how the cycling helmet  82081  is charged. Charge contacts dedicated to the wheel generator  82006  or the assist rechargeable battery  82008  may be directly provided, and to these charge contacts, the charge contacts  82014  of the helmet part  82081   a  may be connected to permit the charging of the cycling helmet  82081 . The charge contacts  82010   a  on the control box  82010  and the dedicated charge contacts provided directly on the wheel generator  82006  or the assist rechargeable battery  82008  are useful also for the charging of a common mobile telephone. 
     The linkage with a bicycle in the one-hundred seventy-first embodiment shown in  FIGS. 272 and 273  is not limited to implementation as a cycling helmet  82081 , but may be adopted also in various headsets that utilize cartilage conduction with the external auditory meatus open as described in other embodiments. 
     One-Hundred Seventy-Second Embodiment 
       FIG. 275  comprises cross-sectional views of a principal part of a one-hundred seventy-second embodiment of the present invention. Like the one-hundred twenty-eighth embodiment shown in  FIGS. 204 to 206  and the one-hundred twenty-ninth embodiment shown in  FIG. 207 , the one-hundred seventy-second embodiment is configured as a touch pen-type handset  83001  that is usable also for touch panel input and that is used in combination with a mobile telephone, and includes a cartilage conduction unit. As in the one-hundred twenty-eighth and one-hundred twenty-ninth embodiment, near-field communication is possible by radio waves  6585  of a communication system such as Bluetooth (a registered trademark). 
       FIG. 275(A)  is a top cross-sectional view of the touch pen-type handset  83001 . A clip portion  83024  serves as the clip of an ordinary pen, and, during use as a handset relying on cartilage conduction, serves also as a cartilage conduction unit that is put in contact with the tragus. For that purpose, the clip portion  83024  is formed of an elastic body having an acoustic impedance similar to that of the tragus, and has inserted in it a piezoelectric bimorph element  83025  which serves as a cartilage-conduction vibration source. Thus, when the piezoelectric bimorph element  83025  is vibrated with a sound signal in an audible range, its vibration conducts to the surface of the clip portion  83024 ; with the tragus put in contact with the surface of the clip portion  83024 , the vibration is conducted to the ear cartilage, and sound can be heard by cartilage conduction. The clip portion  83024 , to fulfill its primary purpose, is provided on the side face of the touch pen-type handset  83001 , and a back part of the clip portion  83024  is, as a cartilage conduction unit, put into contact with the tragus (a left-side part in  FIG. 275(A)  is put into contact with the tragus), so that the side face of the shape of a slim pen serves as a satisfactory cartilage conduction unit. 
     The touch pen-type handset  83001  of the one-hundred seventy-second embodiment, to make the most of being configured to allow sound to be heard by cartilage conduction, is configured such that the diameter of the cross section of the pen is 1.5 cm or less (theoretically, 1 cm or less will do as well). This relies on the mechanism of cartilage conduction: contact with the ear cartilage over a small area (theoretically, point contact will do as well) permits vibration to conduct to the cartilage, so that air conduction sound is generated in the ear canal (external auditory meatus) and then conducts to the eardrum. A slim design as described above would be difficult if a pen-type handset is configured on the assumption that sound generated by an ordinary speaker and then introduced into the ear canal from the outside is heard. 
     As will be clear from  FIG. 275 , the base of the clip portion  83024  is supported on the main body of the touch pen-type handset  83001 , and its elasticity permits the fabric of a pocket in clothing or the like to be tucked between the clip portion  83024  and the main body of the touch pen-type handset  83001 .  FIG. 275(A)  shows the clip portion  83024  in a closed state, with nothing tucked in between. 
     The piezoelectric bimorph element  83025  is connected to a U-shaped resilient metal member  83027 . The resilient metal member  83027  is for conducting vibration to the inside of the main body of the touch pen-type handset  83001 , and is, as will be described later, configured to allow the touch pen-type handset  83001  to function as an incoming-call vibrator by vibrating the piezoelectric bimorph element  83025  with such a low-frequency signal as to arouse a sense of vibration. However, in the state in  FIG. 275(A) , the resilient metal member  83027  lies out of contact with the structure (a projection portion  83001   a ) inside the main body of the touch pen-type handset  83001 , so that vibration is intentionally prevented from conducting. The clip portion  83024  has an acoustic impedance different from that of the main body of the touch pen-type handset  83001 , and this makes it difficult for vibration to conduct to the touch pen-type handset  83001  solely via where it is supported. 
     The projection portion  83001   a  is provided, as will be described later, to make contact with the resilient metal member  83027 , but, as mentioned above, does not make contact in the state in  FIG. 275(A) . A contact detection unit  83067  is for detecting contact between the projection portion  83001   a  and resilient metal member  83027 . A control system  83088  controls the vibration of the piezoelectric bimorph element  83025 , and performs various kinds of control in response to a signal from the contact detection unit  83067 . An incoming-call notifying light-emitting unit  83005  is for notifying, by blinking light, receipt of an incoming call on a mobile telephone. When, as in  FIG. 275(A) , the clip portion  83024  is closed, that is, when the touch pen-type handset  83001  is not worn on a chest pocket but is placed on a table, the incoming-call notifying light-emitting unit  83005  notifies an incoming call by blinking light under the control of the control system  83088 . An operation unit  83009  is a push button, and pressing it in incoming-call responding operation or in call originating operation is responded to by the control system  83088 . 
       FIG. 275(B)  shows a state where the touch pen-type handset  83001  is worn on a chest pocket or the like and, with clothing  83001   b  tucked in, the clip portion  83024  is open. To avoid complication, most of the reference signs identifying the same parts as in  FIG. 275(A)  are omitted; accordingly,  FIG. 275(B)  will be described using the reference signs used in  FIG. 275(A) . In the state in  FIG. 275(B) , the resilient metal member  83027  is in contact with the projection portion  83001   a . Thus, when the piezoelectric bimorph element  83025  is vibrated with a low-frequency signal that arouses a sense of vibration, the vibration conducts to the resilient metal member  83027 , so that the entire touch pen-type handset  83001  vibrates as an incoming-call vibrator. The contact between the resilient metal member  83027  and the projection portion  83001   a  is detected by the contact detection unit  83067 , and under the control of the control system  83088 , light emission by the incoming-call notifying light-emitting unit  83005  is prohibited. The point is that, while an incoming call is notified to the user by vibration, blinking, which is more visible to people around than to the user, is prevented. To avoid malfunction, when the clip portion  83024  is detected being open, under the control of the control system  83088 , operation on the operation unit  83009  is invalidated. 
       FIG. 276  is a system block diagram showing the touch pen-type handset  83001  of the one-hundred seventy-second embodiment along with a mobile telephone  35601  combined with it. The same parts as in  FIG. 275  are identified by the same reference signs, and no overlapping description will be repeated. Most of what is shown in  FIG. 276  is common with the one-hundred twenty-eighth embodiment in  FIG. 205 ; accordingly, common parts are identified by the same reference numerals, and no overlapping description will be repeated. 
     The differences of what is shown in  FIG. 276  from the one-hundred twenty-eighth embodiment in  FIG. 205  will be described. As mentioned above, the one-hundred seventy-second embodiment is configured such that the diameter of the pen is 1.5 cm or less (more preferably, 1 cm or less), and accordingly the display unit is a single-line display unit  83005 . The single-line display unit  83005  is, except whether the shape is flat or cylindrical, common with the display unit  66505  in the one-hundred twenty-ninth embodiment shown in  FIG. 207 . As shown in  FIG. 276 , in the one-hundred seventy-second embodiment, to permit the piezoelectric bimorph element  83025  to be vibrated not only with a sound signal in an audible range for cartilage conduction but also with a low-frequency signal that arouses a sense of vibration to act as an incoming-call vibrator, a sound processing and sense-of-vibration range output unit  83040 . A microphone  35023  is used, as will be described later, also as an input unit for voiceprint authentication for preventing unauthorized use of the touch pen-type handset  83001  by other people when it is stolen. The operation of a control unit  83039  will be described in detail later. 
       FIG. 277  is a table that summarizes different operation conditions in the one-hundred seventy-second embodiment, contrasting various items among a state where the clip portion  83024  is open, a state where the clip portion  83024  is closed and the telephone is on standby, and a state where the clip portion  83024  is closed and a call is in progress. In the state where the clip portion  83024  is open, no call is permitted, and thus the telephone is always on standby. 
     As will be clear from  FIG. 277 , to prevent malfunction as when, with the touch pen-type handset  83001  stuck in a chest pocket, pressure acts on the chest and presses the operation unit  83009 , when the clip portion  83024  is open, incoming-call responding operation and call originating operation are invalidated. When an incoming call is received with the touch pen-type handset  83001  stuck in a chest pocket, taking the touch pen-type handset  83001  out of the pocket causes the clip portion  83024  to be closed, and on detecting this, the incoming call is responded to automatically with no pressing on the operation unit  83009 . 
     As described above with reference to  FIG. 277 , as the clip portion  83024  is opened and closed, whether or not to conduct vibration to the main body of the touch pen-type handset  83001  is switched automatically. Moreover, according to whether or not a call is in progress, whether to output an audible range signal or a sense-of-vibration range signal is switched. When the clip portion  83024  is open, incoming-call notifying light emission is prohibited. 
       FIG. 278  is a basic flow chart related to the operation of the control unit  83039  in the touch pen-type handset  83001  in  FIG. 276 . In the flow in  FIG. 278 , for simplicity&#39;s sake, only such operation as is relevant to the functions of the touch pen-type handset  83001  shown in the operation condition table in  FIG. 277  is illustrated in an extracted manner, and other, general, operation for regular call handling, coordination with the mobile telephone  35601 , and the like is omitted. 
     The flow in  FIG. 278  starts when the operation unit  83009  in the touch pen-type handset  83001  is so operated as to turn the main power on. First, at step S 1182 , pairing of the touch pen-type handset  83001  with the mobile telephone  35601  is performed, and an advance is made to step S 1184 . At step S 1184 , based on detection by the contact detection unit  83067 , whether or not the clip portion  83024  is closed is checked. If the clip portion  83024  is closed, an advance is made to step S 1186 , where incoming-call responding operation and call originating operation on the operation unit  83009  are permitted, and then an advance is made to step S 1188 . At step S 1188 , incoming-call blinking light emission by the incoming-call notifying light-emitting unit  83005  is performed, and an advance is made to step S 1190 , where whether or not a call is in progress is checked. At the start of the flow, no call is in progress, and thus an advance is made to step S 1192 . 
     On the other hand, if, at step S 1184 , the clip portion  83024  is detected not being closed, an advance is made to step S 1194 , where, seeing that the current state corresponds to one where the touch pen-type handset  83001  is stuck in a chest pocket or the like, incoming-call responding operation and call originating operation on the operation unit  83009  are prohibited, and then an advance is made to step S 1196 . At step S 1196 , incoming-call blinking light emission by the incoming-call notifying light-emitting unit  83005  is prohibited, and an advance is made to step S 1198 . At step S 1198 , sound output in an audible range is prohibited, and then, at step S 1200 , output of a sense-of-vibration range signal is permitted, an advance then being made to step S 1192 . In this way, based on the check at step S 1184  of whether or not the clip portion  83024  is closed, the operation conditions of the touch pen-type handset  83001  are changed. 
     At step S 1192 , whether or not there has been an incoming call is checked, and if there has been one, an advance is made to step S 1202 , where whether or not, as a result of the touch pen-type handset  83001  being taken out of a state stuck in the chest pocket or the like, the clip portion  83024  has shifted from the open state to the closed state. If the check result is “no”, an advance is made to step S 1204 , where whether or not there has been incoming-call responding operation on the operation unit  83009  is checked. This is a check for a state that is possible in a situation where the clip portion  83024  is closed. If there has been no incoming-call responding operation, it is judged that the incoming call was not responded to, as by being ignored, and an advance is made to step S 1206 . On the other hand, if, at step S 1192 , there has been no incoming call, an advance is made directly to step S 1206 . 
     At step S 1206 , it is checked whether or not communication partner search operation prior to call origination has been started. If there has been search operation, then an advance is made to step S 1208 , where a partner search process is started, and on completion of the partner search process, an advance is made to step S 12210 . (As will be described later, the partner search process includes recognition of the user&#39;s voiceprint which constitutes a condition for a call.) On the other hand, if, at step S 1206 , there has been no search process, an advance is made directly to Step S 1210 . Then when, at step S 1210 , there is call originating operation on the operation unit  83009  followed by it being responded to by the communication partner, an advance is made to step S 1212 . 
     On the other hand, if, at step S 1202 , the clip portion  83024  is detected having shifted from the open state to the closed state, or if, at step S 1204 , incoming-call responding operation on the operation unit  83009  has been detected, then an advance is made to step S 1214 , where an opening part of the user&#39;s voice for a call (such as “Hello!”) is sampled and is subjected to voiceprint authentication. If voiceprint authentication turns out OK, an advance is made to step S 1212 . 
     At step S 1212 , a call with a communication partner is started. Then, at step S 1216 , output of a sound signal in an audible range is permitted for the call, and at step S 1218 , output of a sense-of-vibration range signal, which is unnecessary, is prohibited, an advance then being made to step S 1220 . At steps S 1216  and S 1218 , if these steps are reached with their respective states already fulfilled, nothing is performed, an advance then being made to the next step. 
     On the other hand, if, at step S 1214 , voiceprint authentication turns out NG, an advance is made to step S 1216 , so that the starting of a call at step S 1212  is skipped. Thus, a user who does not pass voiceprint authentication cannot engage in a call. If, at step S 1190 , it is judged that a call is in progress (corresponding to a case where, up to then, a call started at step S 1212  has been in progress), an advance is made directly to step S 1216 . 
     At step S 1220 , whether or not the main power has been turned off on the operation unit  83009  is checked, and if it has not been turned off, a return is made to step S 1184 . Thereafter, unless the main power is detected being off at step S 1220 , steps S 1184  through S 1220  are repeated to cope with various changes in status. Unless a call is started at step S 1212  and then it is judged that no call is in progress at step S 1190  (in this state, the clip portion  83024  is not opened), a call by cartilage conduction is continued. If, at step S 1220 , the power is detected being off, the flow ends. 
       FIG. 279  is a flow chart showing the details of the partner search process at step S 1208  in  FIG. 278 . When the flow starts, at step S 1222 , voiceprint authentication is performed. This is demanded prior to call originating operation, and in a case where a communication partner is specified by voice input, an opening part of the voice specifying the communication partner is sampled and is subjected to authentication. On the other hand, in a case where a communication partner previously registered with a registration number or the like through simple operation on the operation unit  83009  (such as the number of times pressed) is specified, provisional utterance for voice authentication is performed. If, at step S 1222 , voiceprint authentication turns out NG, a return is made to step S 1184  in  FIG. 278 . In this case, in  FIG. 278 , no advance via step S 1210  to step S 1222  is possible, and thus no call can be started. 
     If, at step S 1222 , voiceprint authentication turns out OK, an advance is made to step S 1224 , where it is checked whether or not operation for specifying a communication partner has been performed within a predetermined period on the operation unit  83009 . If no such operation is detected within the predetermined period, an advance is made to step S 1225 , and thereafter whether or not another predetermined time has elapsed is checked. If the predetermined period has not elapsed, an advance is made to step S 1226 , where whether or not voice specifying a communication partner is input is checked. If there is no voice input, a return is made to step S 1225 , and unless the predetermined period elapses, voice input is waited for. Then when, at step S 1226 , voice input is detected, an advance is made to step S 1228 , where whether or not a communication partner has been specified by voice recognition is checked. If, at step S 1228 , a communication partner has been voice-recognized, an advance is made to step S 1230 ; if not, a return is made to step S 1225 . On the other hand, if, at step S 1224 , operation for specifying a communication partner is detected, an advance is made directly to step S 1230 . 
     At step S 1230 , the recognized communication partner (name or abbreviation) is, as a search key, transmitted to the mobile telephone  35601 . Then, at step S 1332 , a telephone number as a search result is received from the mobile telephone  35601 , and, at step S 1234 , the search result is displayed on the single-line display unit  83005 , an advance then being made to step S 1236 . Also if, at step S 1232 , no search result is received, an advance is made to step S 1238 . Also if, at step S 1225 , it is detected that no voice input is made or no voice recognition succeeds within the predetermined period, an advance is made to step S 1236 . At step S 1236 , in view of various aspects of the progress thus far, it is checked whether or not there has been search stop operation. If there has been no search stop operation, then, at step S 1238 , it is checked whether or not there has been operation for confirming the communication partner based on the search result. If there has been no confirming operation, a return is made to step S 1224 , and thereafter, unless search stop operation is detected at step S 1236  or communication partner confirming operation is detected at step S 1238 , steps S 1224  through S 1238  are repeated so that a search for a communication partner is retried. 
     If, at step S 1238 , communication partner confirming operation is detected, an advance is made to step S 1240 , where the communication partner is transmitted to the mobile telephone  35601  definitively. Now, preparations for call origination are complete. A further advance is made to step S 1242 , where the data, such as the telephone number, received from the mobile telephone  35601  is erased from a storage unit  6537  in the touch pen-type handset  83001 , and an advance is made to step S 1210  in  FIG. 278 . That is, information on a communication partner received as a result of a search for one and the like is for temporary use during the search and is erased after the communication partner is confirmed. Thus, even in case the touch pen-type handset  83001  is lost and is seized by an ill-intentioned person, there is no danger of leakage of information such as of a telephone directory. 
     Also if, at step S 1236 , search stop operation is detected, an advance is made to step S 1242 , where, likewise, the data received from the mobile telephone  35601  through the search function is erased from the storage unit  6537  in the touch pen-type handset  83001 . In this way, even when a communication partner is not confirmed, the data does not remain in the touch pen-type handset  83001 , and thus there is no danger of information leaking to an ill-intentioned person. 
     One-Hundred Seventy-Third Embodiment 
       FIG. 280  comprises cross-sectional views of a principal part of a one-hundred seventy-third embodiment of the present invention. Like the one-hundred seventy-second embodiment shown in  FIGS. 275 to 279 , the one-hundred seventy-third embodiment is configured as a touch pen-type handset  84001  that is usable also for touch panel input and that is used in combination with a mobile telephone, and includes a cartilage conduction unit. As in the one-hundred seventy-second embodiment, near-field communication is possible by radio waves  6585  of a communication system such as Bluetooth (a registered trademark). The one-hundred seventy-third embodiment in  FIG. 280  has much in common with the one-hundred seventy-second embodiment in  FIG. 276 ; accordingly, common parts are identified by the same reference signs, and no overlapping description will be repeated. 
     Like the one-hundred seventy-second embodiment in  FIG. 275 , the one-hundred seventy-third embodiment in  FIG. 280  is shown in a top view of the touch pen-type handset  84001 ,  FIG. 280(A)  showing a state where the clip portion  84024  is closed with nothing tucked in between,  FIG. 280(B)  showing a state where the touch pen-type handset  84001  is worn on a chest pocket or the like and the clip portion  84024  is open with clothing  83001   b  tucked in. 
     A first difference of the one-hundred seventy-third embodiment in  FIG. 280  from the one-hundred seventy-second embodiment in  FIG. 275  is that the clip portion  84024  is formed of a rigid body and is supported on the main body of the touch pen-type handset  84001  via a vibration insulating material  84013  which is an elastic body. A second difference is that the cartilage-conduction vibration source is configured as an electromagnetic vibrator  84025  and is disposed inside the main body of the touch pen-type handset  84001 . Specifically, inside the main body of the touch pen-type handset  84001 , so as not to make contact with its inner wall, the electromagnetic vibrator  84025  is supported on the base of the clip portion  84024 . Thus, the clip portion  84024  is supported on the main body of the touch pen-type handset  84001  via the vibration insulating material  84013 , and the resilience of the vibration insulating material  84013  permits the fabric of a pocket in clothing or the like to be tucked between the clip portion  84024  and the main body of the touch pen-type handset  84001 . The vibration insulating material  84013  makes it difficult for the vibration conducted from the electromagnetic vibrator  84025  to the clip part  84024  to conduct to the main body of the touch pen-type handset  84001 . 
     In the one-hundred seventy-third embodiment in  FIG. 280 , as in the one-hundred seventy-second embodiment in  FIG. 275 , a resilient metal member  84027  is supported on the electromagnetic vibrator  84025  as a cartilage-conduction vibration source. In the state in  FIG. 280(A) , the resilient metal member  84027  is out of contact with the projection portion  83001   a  or the contact detection unit  83067 , and in the state in  FIG. 280(B) , the resilient metal member  84027  is in contact with the projection portion  83001   a  and the contact detection unit  83067 . This too is the same as in one-hundred seventy-second embodiment in  FIG. 275 . In other respects, the one-hundred seventy-third embodiment in  FIG. 280  is similar to the one-hundred seventy-second embodiment in  FIG. 275 , and therefore no overlapping description will be repeated. The construction described in connection with the one-hundred seventy-second embodiment with reference to  FIGS. 276 to 279  applies to the one-hundred seventy-third embodiment in  FIG. 280  as well. 
     The features of the present invention in the embodiments described above are not limited to those embodiments, but may be implemented in any other embodiments so long as they offer their benefits. For example, although the one-hundred seventy-second and one-hundred seventy-third embodiments shown in  FIGS. 275 to 280  are configured as touch pen-type handsets, they may instead be configured as ordinary pens, or may be configured as pen-type cameras or pen-type voice recorders. 
     The handsets usable also for touch panel input in the one-hundred seventy-second and one-hundred seventy-third embodiments may be configured, not simply as handsets, as independent mobile telephones like the ultra-compact mobile telephone  6501  in the sixty-ninth embodiment in  FIG. 101 . In that case, as in the search function in  FIG. 279 , telephone directory data is basically stored in an external server instead of being retained in the mobile telephone, and is downloaded to the mobile telephone only during a search, to be erased from the main power after the search. In that way, as in the one-hundred seventy-second and one-hundred seventy-third embodiments, even in case the mobile telephone is lost and is seized by an ill-intentioned person, there is no danger of leakage of information such as of a telephone directory. A voiceprint authentication function can also be implemented in a mobile telephone for similar purposes. 
     One-Hundred Seventy-Fourth Embodiment 
       FIG. 281  comprises schematic diagrams of a one-hundred seventy-fourth embodiment of the present invention, which is configured as stereo earphones  85001 . The left and right parts of the stereo earphones  85001  are configured symmetrically and similarly, and therefore the following description discusses only one of them, referring to it as “earphone”.  FIG. 281(A)  is an exterior front view of the earphone  85001  as seen from its inner side (the side attached to an ear). The earphone  85001  of the one-hundred seventy-fourth embodiment is, like the one-hundred ninth embodiment in  FIG. 182  for instance, includes a cartilage conduction unit  85024  that is formed of an elastic body with strong resilience and that has a through-hole formed in it for introducing outside sound into the ear canal, the cartilage conduction unit  85024  having coupled to a bottom part of it a hollow sheath portion  85024   b . As in the one-hundred ninth embodiment, a top-end part of a piezoelectric bimorph element as a cartilage-conduction vibration source is, inside the sheath portion  85024   b  without touching its inner wall, directly embedded in and fixed to the bottom part of the cartilage conduction unit  85024 . In a bottom part of the sheath portion  85024   b , a connection cable  85024   d  is led out. 
     The cartilage conduction unit  85024  in the earphone  85001  of the one-hundred seventy-fourth embodiment in  FIG. 281 , like the one shown in  FIG. 182(A)  showing the one-hundred ninth embodiment, is held in the space between the inside of the tragus and the antihelix. Then, the sheath portion  85024   b , in a similar manner as shown in  FIG. 182(A) , hangs down below the ear from the cavum conchae through the intertragic notch. 
     The one-hundred seventy-fourth embodiment in  FIG. 281  differs from the one-hundred ninth embodiment in  FIG. 182  and the like in that an air-conduction sound source is disposed outside the through-hole in the cartilage conduction unit  85024 , and a sound conduction pipe for introducing air-conduction sound generated by the air-conduction sound source into the through-hole is provided. While the combined use of cartilage conduction and air-conduction sound is common with the one-hundred twenty-fourth to one-hundred twenty-seventh embodiments shown in  FIGS. 198 to 203  and the one-hundred thirtieth to one-hundred thirty-third embodiments shown in  FIGS. 208 to 211 , a difference lies in that the air-conduction sound source is disposed at a position away from the cartilage conduction unit  85024  to simplify the structure of the cartilage conduction unit  85024 , resulting in increased freedom in an overall construction that uses cartilage conduction and air-conduction sound in combination. In the specific construction in the one-hundred seventy-fourth embodiment in  FIG. 281 , the air-conduction sound source is disposed inside an air-conduction sound source housing  85024   x  provided at the bottom end of the sheath portion  85024   b . In the one-hundred seventy-fourth embodiment in  FIG. 281 , a directivity producing structure for directing the air-conduction sound introduced into the through-hole in the cartilage conduction unit  85024  toward the ear canal entrance is provided in the cartilage conduction unit  85024 . In this connection, there are shown, in  FIG. 281(A) , an inner through-hole  85024   a  and an outer through-hole  85024   c , the latter having a smaller diameter than the former. 
       FIG. 281(B)  is a cross-sectional view of  FIG. 281(A)  (a cross-sectional view along line B 1 -B 1  in  FIG. 281(C)  referred to later, which is a cross-sectional view obtained by rotating  FIG. 281(B)  through 90 degrees), and the same parts as in  FIG. 281(A)  are identified by the same reference numerals. For such parts in  FIG. 281(B)  showing the one-hundred seventy-fourth embodiment as are common with  FIG. 208(B)  showing the one-hundred thirtieth embodiment, no overlapping description will be repeated. Specifically, the features that a top-end part of a piezoelectric bimorph element  85025  as a cartilage-conduction vibration source is supported on a cartilage conduction unit  85024  which is an elastic body, and an other-end part vibrates freely inside a hollow sheath portion  85024   b  without touching its inner wall are common with the one-hundred thirtieth embodiment described in detail with reference to  FIG. 208(B) . 
     As will be clear from  FIG. 281(B) , inside the air-conduction sound source housing  85024   x , there is disposed an air-conduction sound source  85027  which is controlled independently of an electromagnetic vibrator  85025  as a cartilage-conduction vibration source. The conduction sound source  85027  is, specifically, an electromagnetic air-conduction sound speaker having a vibration plate (diaphragm)  85027   a . The air-conduction sound generated by the vibration plate  85027   a  is conducted upward as seen in the diagram through the hollow sheath portion  85024   b  which doubles as a sound conduction pipe lower part, and is introduced into an inner through-hole  85024   a  through a sound conduction pipe upper part  85024   y  penetrating the cartilage conduction unit  85024  and open on the inner wall of the inner through-hole  85024   a . Thus, while cartilage conduction sound produced by contact between the outside of the cartilage conduction unit  85024  and the ear cartilage mainly covers mid- and low-range sound, air-conduction sound that is introduced into the inner through-hole  85024   a  through the sheath portion  85024   b  doubling as the sound conduction pipe lower part and the sound conduction pipe upper part  85024   y  mainly covers high-range sound. 
     In the above construction, the sheath portion  85024   b  doubling as the sound conduction pipe lower part is formed of a material (for example, rigid plastic) with an acoustic impedance different from that of the cartilage conduction unit  85024  which is formed of an elastic body. This restrains the vibration of the cartilage conduction unit  85024  to which the vibration of the electromagnetic vibrator  85025  is conducted from conducting to the sound conduction pipe lower part and causing leakage of air-conduction sound through the outer wall of the sound conduction pipe lower part. 
       FIG. 281(C)  is a cross-sectional view obtained, as mentioned above, by rotating  FIG. 281(B)  through 90 degrees. The same parts as in  FIGS. 281(A) and 281(B)  are identified by the same reference numerals. In  FIG. 281(C) , the right side along the plane of the drawing is the side (inner side) attached to an ear. As will be clear from  FIG. 281(C) , the diameter of the outer through-hole  85024   c  pointing outward is smaller than the diameter of the inner through-hole  85024   a  pointing to the earhole. This permits the air-conduction sound introduced through the sound conduction pipe upper part  85024   y  into the inner through-hole  85024   a  to be reflected on the inner wall of the outer through-hole  85024   c , and thereby makes it directional toward the ear canal entrance. This directivity producing structure also reduces leakage of sound to the outside through the outer through-hole  85024   c . As will be clear from  FIGS. 281(B) and 281(C) , the directivity producing structure in the one-hundred seventy-fourth embodiment is concentric with the axis of the through-hole pointing to the ear canal. 
       FIG. 281(D)  is a cross-sectional view from the same direction as  FIG. 281(C)  and shows a cross-section along line B 2 -B 2  in  FIG. 281(B) . Being a cross-section at a position displaced from the sound conduction pipe upper part  85024   y ,  FIG. 281(D)  does not show the sound conduction pipe upper part  85024   y . To avoid complication,  FIG. 281(D)  has no reference signs. 
       FIG. 282  is a block diagram of the one-hundred seventy-fourth embodiment in  FIG. 281 , showing a state where a right-ear earphone  85001   a  and a left-ear earphone  85001   b  are connected to a mobile music terminal  69001 . The configuration of the mobile music terminal  69001  is mostly common with the one-hundred sixty-second embodiment in  FIG. 255  directed likewise to stereo earphones; accordingly, similar elements are identified by the same reference signs, and no overlapping description will be repeated. Such elements as find their counterparts in  FIG. 281  are identified by the same reference signs, and no overlapping description will be repeated. In an earphone drive unit  69036  in the mobile music terminal  69001 , a stereo acoustic processing unit  85038  separates a stereo sound signal into a cartilage-conduction stereo signal and an air-conduction stereo signal, and delivers them to a stereo cartilage-conduction equalizer  85038   a  and a stereo air-conduction equalizer  85038   b  respectively. 
     The cartilage-conduction equalizer  85038   a  makes a stereo cartilage-conduction drive unit  85040   a  drive a cartilage-conduction vibration source  85025   b  in the left-ear earphone  85001   b  and a cartilage-conduction vibration source  85025   a  in the right-ear earphone  85001   a  of which each comprises a piezoelectric bimorph. On the other hand, the air-conduction equalizer  85038   b  makes a stereo air-conduction drive unit  85040   b  drive an air-conduction speaker  85027   b  in the left-ear earphone  85001   b  and an air-conduction speaker  85027   a  in the right-ear earphone  85001   a . In this way, in the one-hundred seventy-fourth embodiment, the stereo cartilage-conduction vibration sources  85035   a  and  85035   b , and also the air-conduction speakers  85027   a  and  85027   b , are controllable independently of each other in each pair, achieving sound control by equalizing such that the former mainly covers mid- and low-range sound and the latter mainly covers high-range sound. 
     One-Hundred Seventy-Fifth Embodiment 
       FIG. 283  comprises schematic diagrams of a one-hundred seventy-fifth embodiment of the present invention, which is configured as stereo earphones  86001 . The one-hundred seventy-fifth embodiment in  FIG. 283  has much in common with one-hundred seventy-fourth embodiment in  FIG. 281 ; accordingly, corresponding parts are identified by the same reference signs, and no overlapping description will be repeated. 
     The one-hundred seventy-fifth embodiment in  FIG. 283  differs from the one-hundred seventy-fourth embodiment in  FIG. 281  in the directivity producing structure of the cartilage conduction unit  86024  for directing the air-conduction sound introduced into the inner through-hole  86024   a  toward the ear canal entrance. Specifically, in the one-hundred seventy-fifth embodiment, there is provided a turned-back portion  86024   z  extending from the outer through-hole  86024   c  toward the ear canal, In  FIG. 283(A) , an end part of the turned-back portion  86024   z  is shown along with the inner through-hole  86024   a  and the outer through-hole  86024   c.    
       FIG. 283(B)  is a cross-sectional view of  FIG. 283(A)  (a cross-sectional view along line B 1 -B 1  in  FIG. 283(C)  referred to later, which is a cross-sectional view obtained by rotating  FIG. 283(B)  through 90 degrees), and the same parts as in  FIG. 283(A)  are identified by the same reference numerals. In  FIG. 283(B) , a cross-section of the turned-back portion  86024   z  is illustrated. In  FIG. 283(C) , the shape of the turned-back portion  86024   z  inside the inner through-hole  86024   a  is illustrated in more detail. As will be understood from  FIG. 283(C) , providing the turned-back portion  86024   z  permits a ring-shaped reentering portion  86000  to be formed inside the inner through-hole  86024   a , so that air-conduction sound having passed through the sound conduction pipe upper part  86024   y  is, by being ejected into the ring-shaped reentering portion  86000 , made directional toward the ear canal entrance. This directivity producing structure reduces leakage of sound to the outside through the outer through-hole  86024   c . As will be clear from  FIGS. 283(B) and 283(C) , also the directivity producing structure in the one-hundred seventy-fifth embodiment is concentric with the axis of the through-hole pointing to the ear canal. 
       FIG. 283(D)  is a cross-sectional view from the same direction as  FIG. 283(C) , and shows a cross-section along line B 2 -B 2  in  FIG. 283(B) . Like  FIG. 281(D)  showing the one-hundred seventy-fourth embodiment, being a cross-section at a position displaced from the sound conduction pipe upper part  86024   y ,  FIG. 283(D)  does not show the sound conduction pipe upper part  86024   y . As in the one-hundred seventy-fourth embodiment, to avoid complication,  FIG. 283(D)  has no reference signs. 
     One-Hundred Seventy-Sixth Embodiment 
       FIG. 284  comprises schematic diagrams of a one-hundred seventy-sixth embodiment of the present invention, which is configured as stereo earphones  87001 . The one-hundred seventy-sixth embodiment in  FIG. 284  has much in common with one-hundred seventy-fourth embodiment in  FIG. 281 ; accordingly, corresponding parts are identified by the same reference signs, and no overlapping description will be repeated. 
     The one-hundred seventy-sixth embodiment in  FIG. 284  differs from the one-hundred seventy-fourth embodiment in  FIG. 281  in the directivity producing structure of the cartilage conduction unit  87024  for directing the air-conduction sound introduced into the through-hole  87024   a  toward the ear canal entrance. Specifically, in the one-hundred seventy-sixth embodiment, the sound conduction pipe upper part  87024   y  is branched off the sheath portion  87024   b  constituting the sound conduction pipe lower part, and is extended into the through-hole  87024   a , so that there is provided an air-conduction sound discharge port  87000  which points to the ear canal entrance. In  FIG. 284(A) , the sound conduction pipe upper part  87024   y  extended into the through-hole  87024   a  and the air-conduction sound discharge port  87000  pointing to the ear canal entrance are illustrated. In the one-hundred seventy-sixth embodiment, the through-hole  87024   a  has the same inner and outer diameters. 
       FIG. 284(B)  is a cross-sectional view of  FIG. 284(A)  (a cross-sectional view along line B 1 -B 1  in  FIG. 284(C)  referred to later, which is a cross-sectional view obtained by rotating  FIG. 284(B)  through 90 degrees), and the same parts as in  FIG. 284(A)  are identified by the same reference numerals. In  FIG. 284(B) , a cross-section of the air-conduction sound discharge port  87000  is illustrated. In  FIG. 284(C) , the structure where the sound conduction pipe upper part  87024   y  is branched off the sheath portion  85024   b  constituting the sound conduction pipe lower part and is extended into the through-hole  87024   a  to form the air-conduction sound discharge port  87000  pointing to the ear canal entrance is illustrated more clearly. As will be understood from  FIG. 284(C) , air-conduction sound having passed through the sound conduction pipe upper part  87024   y  is, by being ejected out of the air-conduction sound discharge port  87000 , made directional toward the ear canal entrance. This directivity producing structure reduces leakage of sound to the outside through the through-hole  87024   a . The air-conduction sound discharge port  87000  is located to be concentric with the axis of the through-hole pointing to the ear canal. 
       FIG. 284(D)  is a cross-sectional view from the same direction as  FIG. 284(C) , and shows a cross-section along line B 2 -B 2  in  FIG. 284(B) . Being a cross section displaced from the sound conduction pipe upper part  87024   y  extended into the through-hole  87024   a ,  FIG. 284(D)  shows neither the sound conduction pipe upper part  87024   y  nor the air-conduction sound discharge port  87000 . As with the one-hundred seventy-fourth and other embodiments, to avoid complication,  FIG. 284(D)  has no reference signs. As will be clear from  FIG. 284 , the sound conduction pipe upper part  87024   y  and the air-conduction sound discharge port  87000  in the one-hundred seventy-sixth embodiment are so disposed as not to hinder outside sound from being introduced through the through-hole  87024   a  into the ear canal. 
     One-Hundred Seventy-Seventh Embodiment 
       FIG. 285  comprises schematic diagrams of a one-hundred seventy-seventh embodiment of the present invention, which is configured as stereo earphones  88001 . The one-hundred seventy-seventh embodiment in  FIG. 285  has much in common with one-hundred seventy-fourth embodiment in  FIG. 281 ; accordingly, corresponding parts are identified by the same reference signs, and no overlapping description will be repeated. 
     The one-hundred seventy-seventh embodiment in  FIG. 285  differs from the one-hundred seventy-fourth embodiment in  FIG. 281  in that a vibration plate that serves as an air-conduction sound source is vibrated with vibration energy shared with a cartilage-conduction vibration source. This difference, however, is not apparent in the front view in  FIG. 285(A) . 
       FIG. 285(B)  is a cross-sectional view of  FIG. 285(A)  (a cross-sectional view along line B 1 -B 1  in  FIG. 285(C)  referred to later, which is a cross-sectional view obtained by rotating  FIG. 285(B)  through 90 degrees), and the same parts as in  FIG. 285(A)  are identified by the same reference numerals. For such parts in  FIG. 285(B)  showing the one-hundred seventy-seventh embodiment as are common with  FIG. 208(B)  showing the one-hundred thirtieth embodiment, no overlapping description will be repeated. Specifically, the features that a top-end part of a piezoelectric bimorph element  88025  as a cartilage-conduction vibration source is supported on a cartilage conduction unit  88024  which is an elastic body, and an other-end part vibrates freely inside a hollow sheath portion  88024   b  without touching its inner wall are common with the one-hundred thirtieth embodiment described in detail with reference to  FIG. 208(B) . 
     As will be clear from  FIG. 285(B) , in the one-hundred seventy-seventh embodiment, the piezoelectric bimorph  88025  as a cartilage-conduction vibration source has, in an other-end part which vibrates freely, a vibration plate  88027   a  attached to it. To secure an area necessary for the vibration plate  88027   a , the air-conduction sound source housing  88024   x  is larger than a middle part of the sheath portion  88024   b . With this structure, air-conduction sound generated by the vibration plate  88027   a  is introduced, from the hollow sheath portion  88024   b  doubling as the sound conduction pipe lower part via the sound conduction pipe upper part  85024   y  open on the inner wall of the inner through-hole  85024   a , into the inner through-hole  85024   a . The construction that permits the generated air-conduction sound to be introduced into the inner through-hole  85024   a  is common with the one-hundred seventy-fourth embodiment in  FIG. 281 . 
     In  FIG. 285(C) , the construction where the vibration plate  88027   a  is attached to the freely vibrating other-end part of the piezoelectric bimorph  88025  so that the vibration plate  88027   a  is vibrated by sharing the vibration energy of the piezoelectric bimorph  88025  as a cartilage-conduction vibration source is illustrated clearly. In the one-hundred seventy-seventh embodiment, no speaker or the like for vibrating the vibration plate  88027   a  is needed; thus, there is no need to give the air-conduction sound source housing  88024   x  a thickness larger than that of a middle part of the sheath portion  88024   b . On the other hand, however, due to the shared vibration source, equalization for cartilage conduction and air-conduction sound generation is performed not independently but in an integrated fashion with consideration given to the balance between cartilage conduction and air-conduction sound generation. 
       FIG. 285(D)  is a cross-sectional view from the same direction as  FIG. 285(C) , and shows a cross section along line B 2 -B 2  in  FIG. 285(B) . Like  FIG. 281(D)  showing the one-hundred seventy-fourth embodiment, being a cross section at a position displaced from the sound conduction pipe upper part  85024   y ,  FIG. 281(D)  does not show the sound conduction pipe upper part  85024   y . To avoid complication,  FIG. 285(D)  has no reference signs. 
     One-Hundred Seventy-Eighth Embodiment 
       FIG. 286  comprises schematic diagrams of a one-hundred seventy-eighth embodiment of the present invention, which is configured as stereo earphones  89001 . The one-hundred seventy-eighth embodiment in  FIG. 286  has much in common with one-hundred seventy-fourth embodiment in  FIG. 281 ; accordingly, corresponding parts are identified by the same reference signs, and no overlapping description will be repeated. 
     The one-hundred seventy-eighth embodiment in  FIG. 286  differs from the one-hundred seventy-fourth embodiment in  FIG. 281  in that a cartilage-conduction vibration source is not vibrated inside the sheath portion  89024   b  but is disposed in a form embedded in the cartilage conduction unit  89024 . 
       FIG. 286(B)  is a cross-sectional view of  FIG. 286(A)  (a cross-sectional view along line B 1 -B 1  in  FIG. 286(C)  referred to later, which is a cross-sectional view obtained by rotating  FIG. 286(B)  through 90 degrees), and the same parts as in  FIG. 286(A)  are identified by the same reference numerals. For such parts in  FIG. 286(B)  showing the one-hundred seventy-eighth embodiment as are common with  FIG. 208(B)  showing the one-hundred thirtieth embodiment, no overlapping description will be repeated. 
     As will be clear from  FIG. 286(B) , in the one-hundred seventy-eighth embodiment, a pair of cartilage-conduction vibration sources  89025  is disposed in a form embedded in the cartilage conduction unit  89024  around the inner through-hole  85024   a . Accordingly, in the one-hundred seventy-eighth embodiment, the sheath portion  89024   b  constitutes a dedicated sound conduction pipe lower part that connects to the sound conduction pipe upper part  89024   y  to introduce air-conduction sound from the conduction sound source  85027 . 
     Owing to the arrangement described above, the cross-sectional view in  FIG. 286(C)  does not show the pair of cartilage-conduction vibration sources  89025 . By contrast,  FIG. 286(D) , which is a cross-sectional view from the same direction as  FIG. 286(C)  and shows a cross section along line B 2 -B 2  in  FIG. 286(B) , shows the cartilage-conduction vibration sources  89025 . In the one-hundred seventy-eighth embodiment in  FIG. 286 , the cartilage-conduction vibration sources  89025  embedded in the cartilage conduction unit  89024  can be compact piezoelectric bimorph elements  66025   a  and  66025   b  as in the one-hundred sixtieth embodiment in  FIG. 256 , or compact electromagnetic vibrators as in  FIG. 262(A) . 
     One-Hundred Seventy-Ninth Embodiment 
       FIG. 287  comprises schematic diagrams of a one-hundred seventy-ninth embodiment of the present invention, which is configured as a stereo headset  90001 . The one-hundred seventy-ninth embodiment in  FIG. 287  has much in common with one-hundred seventy-fourth embodiment in  FIG. 281 ; accordingly, corresponding parts are identified by the same reference signs, and no overlapping description will be repeated. 
     The one-hundred seventy-ninth embodiment in  FIG. 287  differs from the one-hundred seventy-fourth embodiment in  FIG. 281  in that each earphone has its own power supply unit and incorporates a circuit unit including an acoustic processing unit, a wireless communication unit, and the like so that the pair of earphones, to be worn on the left and right ears respectively, is configured as a headset. As shown in  FIG. 287(A)  showing the exterior appearance, the circuit unit mentioned above is housed, along with an air-conduction sound source, in a casing part  90024   x  disposed away from the cartilage conduction unit  85024 . 
       FIG. 287(B)  is a cross-sectional view of  FIG. 287(A)  (a cross-sectional view along line B 1 -B 1  in  FIG. 287(C)  referred to later, which is a cross-sectional view obtained by rotating  FIG. 287(B)  through 90 degrees), and the same parts as in  FIG. 287(A)  are identified by the same reference numerals. For such parts in  FIG. 287(B)  showing the one-hundred seventy-ninth embodiment as are common with  FIG. 208(B)  showing the one-hundred thirtieth embodiment, no overlapping description will be repeated. 
     As will be clear from  FIG. 287(B) , in the one-hundred seventy-ninth embodiment, the air-conduction sound source housing  90024   x  houses the conduction sound source  85027  and the circuit unit  90000 . The construction that permits the air-conduction sound generated from the conduction sound source  85027  to be delivered to the cartilage conduction unit  85024  is common with the one-hundred seventy-fourth embodiment in  FIG. 281 . This will be clear also from the cross section in  FIG. 287(C) . Like  FIG. 281(D)  showing the one-hundred seventy-fourth embodiment,  FIG. 287(D) , which is a cross-sectional view from the same direction as  FIG. 287(C)  and shows a cross section along line B 2 -B 2  in  FIG. 287(B) , does not show the sound conduction pipe upper part  85024   y . To avoid complication,  FIG. 287(D)  too has no reference signs. 
       FIG. 288  is a block diagram of the one-hundred seventy-ninth embodiment in  FIG. 287 . The one-hundred seventy-ninth embodiment is directed to a headset comprising a pair of earphones, for the right and left ears respectively, of which one is configured as shown in FIG.  288 , the other being configured similarly. Near-field communication units  69046  receive sound signals for the right and left ears respectively, and drive cartilage-conduction vibration sources  85025  and air-conduction speakers  85027  respectively. The configuration in  FIG. 288  has much in common with the block diagram of the one-hundred seventy-fourth embodiment in  FIG. 282 ; accordingly, corresponding parts are identified by the same reference signs, and no overlapping description will be repeated. 
     The block diagram of the one-hundred seventy-ninth embodiment in  FIG. 288  differs from the block diagram of the one-hundred seventy-fourth embodiment in  FIG. 282  in that, whereas stereo sound signals are handled in the latter, a sound signal (monaural sound signal) for the right or left ear is handled in the former. Specifically, in the block diagram of the one-hundred seventy-ninth embodiment in  FIG. 179 , the acoustic processing unit  85038 , the cartilage-conduction equalizer  85038   a , the air-conduction equalizer  85038   b , the cartilage-conduction drive unit  85040   a , and the air-conduction drive unit  85040   b  all handle a sound signal for the right or left ear. In other respects, the configuration here can be understood based on  FIG. 282 , and therefore no overlapping description will be repeated. 
     One-Hundred Eightieth Embodiment 
       FIG. 289  comprises front views showing a one-hundred eightieth embodiment of the present invention and a modified example of it along with the one-hundred seventy-fourth embodiment for reference, each configured as stereo earphones or a stereo headset.  FIG. 289(A)  is, for reference, a front view (corresponding to a side of the face) of the right-ear part of the headset worn on the right ear  28 , and there, for simplicity&#39;s sake, the part of the face other than the right ear  28  is omitted from illustration. Moreover, to avoid complicated illustration, while the right ear  28  is indicated by solid lines, the structure of the right-ear part of the headset worn on it is indicated by broken lines. 
     As will be clear from  FIG. 289(A) , in the one-hundred seventy-fourth embodiment, the cartilage conduction unit  85024  is held in the space between the inside of the tragus  32  and the antihelix  28   f . Here, the sheath portion  85024   b  hangs down below the ear from the cavum conchae through the intertragic notch  28   f.    
     By contrast,  FIG. 289(B)  shows a state where a right-ear part of the headset according to the one-hundred eightieth embodiment is worn on the right ear  28 . In the one-hundred eightieth embodiment, while it has an internal construction common with the one-hundred seventy-fourth embodiment, the sound conduction pipe portion  91024   b  between a sheath portion  85024   b , where a piezoelectric bimorph is housed, and an air-conduction sound source housing portion  85024   x  is extended and bent into the shape of an ear hook. Specifically, the sound conduction pipe portion  91024   b  bends from the incisura anterior  28   h  via a top part of the auricle to a rear part of the auricle. As a result, while there is a common feature that the cartilage conduction unit  85024  is held between the inside of the tragus  32  and the antihelix  28   a , the air-conduction sound source housing portion  85024   x  is located at a rear part of the auricle. 
     On the other hand,  FIG. 289(C)  shows a state where a right-ear part of a headset according to a modified example of the one-hundred eightieth embodiment is worn on the right ear  28 . In the modified example of the one-hundred eightieth embodiment, while it too has an internal construction common with the one-hundred seventy-fourth embodiment, the sound conduction pipe portion  92024   b  between a sheath portion  85024   b , where a piezoelectric bimorph is housed, and an air-conduction sound source housing portion  85024   x  is extended and bent into the shape of an earpiece. Specifically, the sound conduction pipe portion  92024   b  bends from the intertragic notch  28   f  via a bottom part of the auricle to a rear part of the auricle. As a result, also in the modified example, while there is a common feature that the cartilage conduction unit  85024  is held between the inside of the tragus  32  and the antihelix  28   a , the air-conduction sound source housing portion  85024   x  is located at a rear part of the auricle. 
     Some embodiments of the present invention are configured as stereo earphones or stereo headsets. Conventionally known mechanisms of sound hearing are air conduction and bone conduction. In bone conduction, the cranium is vibrated forcibly; this makes it impossible to hear different sound in the left and right inner ears, making stereophonic sound hearing impossible. By contrast, the present invention employs a mechanism of cartilage conduction in which air-conduction sound generated inside the ear canal reaches the eardrum to allow sound hearing, and is suitable to improve sound quality in stereophonic sound hearing. 
     The features of the present invention in the embodiments described above are not limited to those embodiments, but may be implemented in any other embodiments so long as they offer their benefits. For example, the constructions shown in  FIGS. 289(B)  and (C) where the sound conduction pipe portion is bent are applicable not only to the one-hundred seventy-fourth embodiment shown in  FIG. 281  but also, as necessary, to the one-hundred seventy-fifth embodiment in  FIG. 283 , the one-hundred seventy-sixth embodiment, in  FIG. 284 , the one-hundred seventy-eighth embodiment in  FIG. 286 , the one-hundred seventy-ninth embodiment in  FIG. 287 , and the like. In a case where a structure with a bent sound conduction pipe portion is applied to the one-hundred seventy-ninth embodiment in  FIG. 287 , a circuit unit including at least a power supply unit is disposed at a rear part of the auricle. 
     One-Hundred Eighty-First Embodiment 
       FIG. 290  is a perspective view related to a one-hundred eighty-first embodiment of the present invention, which is configured as a mobile telephone. The mobile telephone is a modular smartphone of which a component module is replaceable/interchangeable, and illustrated is a state where an air-conduction speaker module  93013  is inserted in a slot  93001   a  in a mobile telephone body  93001 . The air-conduction speaker module  93013  includes an air-conduction speaker  93013   a  and a videophone inner camera  93013   b . The air-conduction speaker  93013   a  is an ordinary speaker that generates air-conduction sound, and is disposed at the middle of the air-conduction speaker module  93013  so that it can be used likewise with either the right or left ear put on it. Accordingly, in a state as in  FIG. 290  where the air-conduction speaker module  93013  is inserted in the slot  93001   a , the user can, in an ordinary posture with the mobile telephone body  93001  put on an ear, conduct an ordinary call using the air-conduction speaker  93013   a  and a microphone  93023 . 
     Increasing the output level of the air-conduction speaker  93013   a  permits it to be used along with the videophone inner camera  93013   b  in a videophone call. At that time, also the sensitivity level of the microphone  93023  is increased. Accordingly, in a state as in  FIG. 290  where the air-conduction speaker module  93013  is inserted in the slot  93001   a , the user can conduct a videophone call while viewing the partner&#39;s face displayed on a large-screen display unit  93205 . The large-screen display unit  93205  doubles as a touch panel that allows GUI operation, where, prior to a call, an operation unit  93209  such as a numeric keypad is displayed so that the user can, by touching it, enter the partner&#39;s telephone number and the like. 
       FIG. 291  shows a state where, in the one-hundred eighty-first embodiment in  FIG. 290 , the air-conduction speaker module  93013  is removed from the slot  93001   a  and instead a cartilage conduction module  93027  is inserted in it. The cartilage conduction module  93027  includes a right elastic-body cartilage conduction unit  93024  and a left elastic-body cartilage conduction unit  93026 . As shown in  FIG. 291 , when the cartilage conduction module  93027  is inserted in the slot  93001   a , the right and left elastic-body cartilage conduction units  93024  and  93026  are located respectively near opposite corner parts of a top part of the mobile telephone body  93001 . 
     Thus, when the front side of the right elastic-body cartilage conduction unit  93024  is put to a cartilage (such as the tragus) around the ear canal entrance of the right ear, as in other embodiments, a cartilage conduction call with the right ear is possible. On the other hand, when the front side of the left elastic-body cartilage conduction unit  93026  is put to a cartilage (such as the tragus) around the ear canal entrance of the left ear, a cartilage conduction call with the left ear is possible. This provides a comfortable calling posture in which, as in other embodiments, a top corner part of the mobile telephone body  93001  fits the shape of the cavum conchae. As already mentioned, the cavum conchae is open frontward except that the soft tragus juts out, and this permits a top corner part of the mobile telephone body  93001  to fit in the auricle without compressing it. (In the construction of the one-hundred eighty-first embodiment, the user can choose to hear with the side face of either of the right and left elastic-body cartilage conduction units  93024  and  93026  put on the ear cartilage). 
     On the right elastic-body cartilage conduction unit  93024 , there is supported a right vibration source (unillustrated) like the piezoelectric bimorph element  2525   b  in the fifty-second embodiment in  FIG. 78  (here, however, a compact one is used with one-third or less of the total length of the cartilage conduction module  93027 ) or the electromagnetic vibrator  4324  in the forty-eighth embodiment in  FIG. 73 . Likewise, on the left elastic-body cartilage conduction unit  93026 , symmetrically left-to-right, there is supported a left vibration source (unillustrated) like the one in the right elastic-body cartilage conduction unit  93024 . These right and left vibration sources vibrate without making contact with a middle part of the cartilage conduction module  93027 , which is a rigid body structure. Accordingly, due to the difference in acoustic impedance between, at one end, the right and left elastic-body cartilage conduction units  93024  and  93026  and, at the other end, the rigid body structure of the cartilage conduction module  93027 , the vibration of the right and left vibration sources is prevented from conducting to a videophone inner camera  93017  and a videophone speaker  93051  which are disposed in a middle part of the cartilage conduction module  93027 . On the other hand, the right and left elastic-body cartilage conduction units  93024  and  93026  have an acoustic impedance similar to that of the ear cartilage, and thus, when in contact with the ear cartilage, they produce suitable cartilage conduction. 
     The videophone speaker  93051  is an ordinary speaker that generates air-conduction sound. In a videophone call using the videophone inner camera  93017 , the function of the right and left elastic-body cartilage conduction units  93024  and  93026  is stopped, and instead the videophone speaker  93051  comes into operation. In a videophone call, as in the case in  FIG. 290 , the sensitivity level of the microphone  93023  is increased. Accordingly, even in a state as in  FIG. 291  where the cartilage conduction module  93027  is inserted in the slot  93001   a , the user can conduct a videophone call while viewing the partner&#39;s face displayed on the large-screen display unit  93205 . 
       FIG. 292  comprises perspective views illustrating how the cartilage conduction module  93027  is inserted in the slot  93001   a . The same parts as in  FIG. 291  are identified by the same reference signs, and no overlapping description will be repeated unless necessary. 
       FIG. 292(A)  shows a state before the cartilage conduction module  93027  is inserted in the slot  93001   a  in the mobile telephone body  93001 . In a left part of the inner face of the slot  93001   a , a body-side contact unit  93001   b  is disposed. Correspondingly, on the rear face of the cartilage conduction module  93027 , a module-side contact unit  93027   a  is disposed. As will be described later, these contact units connect together when the cartilage conduction module  93027  is inserted into the slot  93001   a . Though no illustration is given, a similar module-side contact unit is disposed also on the rear face of the air-conduction speaker module  93013  shown in  FIG. 290 , and in a state as in  FIG. 290  where the air-conduction speaker module  93013  is inserted in the slot  93001   a , it connects to the body-side contact unit  93001   b.    
     As shown in  FIG. 292(B) , the cartilage conduction module  93027  is inserted by being slid in from the left side of the slot  93001   a .  FIG. 292(C)  shows a state after the completion of insertion, and corresponds to  FIG. 291 . In the state in  FIG. 292(C) , the body-side contact unit  93001   b  and the module-side contact unit  93027   a  are at coincident positions, and are connected together. 
     As described above, a first function of the right and left elastic-body cartilage conduction units  93024  and  93026  is, while suppressing the conduction of the vibration of a vibration source to the videophone inner camera  93017  and the like, to produce suitable cartilage conduction when in contact with the ear cartilage. A second function of the right and left elastic-body cartilage conduction units  93024  and  93026  is to prevent the cartilage conduction module  93027  from clattering inside the slot  93001   a  due to the vibration of a vibration source. 
     What has just been mentioned will now be described a little further. As shown in  FIG. 292 , since the cartilage conduction module  93027  is inserted into the slot  93001   a  by being slid in, to permit such sliding, a small gap is left between the outer face of the cartilage conduction module  93027  and the inner face of the slot  93001   a . Thus, in general, when the cartilage conduction module  93027  vibrates inside the slot  93001   a , the outer face of the cartilage conduction module  93027  and the inner face of the slot  93001   a  may collide with each other repeatedly and thus clatter. 
     Here, in contrast, owing to the right and left elastic-body cartilage conduction units  93024  and  93026  being formed of an elastic material, when the front side of the right elastic-body cartilage conduction unit  93024  is put on the cartilage around the ear canal entrance of the right ear, the right elastic-body cartilage conduction unit  93024  is pressed against the inner face of the slot  93001   a , and this prevents clattering; in addition, the inner face of the slot  93001   a  provides a support when the right elastic-body cartilage conduction unit  93024  is put on the cartilage around the ear canal entrance of the right ear. The same is true with the left elastic-body cartilage conduction unit  93026 . Accordingly, the construction of the one-hundred eighty-first embodiment is one that, despite allowing the cartilage conduction module  93027  to be inserted into the slot  93001   a  by being slid in, does not impair cartilage conduction. 
       FIG. 293  is a block diagram of the one-hundred eighty-first embodiment in the state in  FIG. 291  where the cartilage conduction module  93027  is inserted in the slot  93001   a  in the mobile telephone body  93001 . The same parts as in the  FIGS. 291 and 292  are identified by the same reference signs, and no overlapping description will be repeated unless necessary. In the configuration of the mobile telephone body  93001  in  FIG. 293 , such parts as find their counterparts in the mobile telephone lower part  6701   a  in the embodiment in  FIG. 106  are identified by the same reference signs, and no overlapping description will be repeated unless necessary. 
     In the cartilage conduction module  93027  in  FIG. 293 , the right and left elastic-body cartilage conduction units  93024  and  93026  include right and left vibration sources  93025   b  and  93025   a  respectively, and are driven by right and left drive units  93035  and  93036  respectively. As already mentioned, the right and left vibration sources  93025   b  and  93025   a  conduct vibration directly only to the right and left elastic-body cartilage conduction units  93024  and  93026  respectively, and vibrate without making contact with the casing part of the cartilage conduction module  93027 , which is a rigid body structure. 
     The module-side contact unit  93027   a  feeds a sound signal received, through contact with the body-side contact unit  93001   b , from an incoming-call processing unit  212  in the mobile telephone body  93001  to a switching control unit  93040  across a signal line  93040   a . The switching control unit  93040  receives, through contact with the body-side contact unit  93001   b , a call mode signal from a controller  239  in the mobile telephone body  93001  across a signal line  93040   b . If the call mode signal indicates a normal call mode, the switching control unit  93040  feeds the sound signal received from the cartilage-conduction drive unit  85040   a  to a cartilage conduction equalizer  93138 . The cartilage conduction equalizer  93138  applies frequency characteristics correction peculiar to cartilage conduction to the sound signal and then feeds it to the right and left drive units  93035  and  93036  respectively to drive the right and left vibration sources  93025   b  and  93025   a . On the other hand, if the call mode signal indicates a videophone mode, the switching control unit  93040  feeds the sound signal received from the signal line  93040   a  to the videophone speaker  93051 . At this time, the right and left drive units  93035  and  93036  are out of operation, so that the right and left vibration sources  93025   b  and  93025   a  do not vibrate. 
     The right and left vibration sources  93025   b  and  93025   a  function as pressure sensors like that described in connection with the fourth embodiment in  FIG. 9 , and detect whether or not either of the right and left elastic-body cartilage conduction units  93024  and  93026  is in contact with an ear cartilage. When, via signal lines  93040   d  and  93940   c , neither of the right and left elastic-body cartilage conduction units  93024  and  93026  is detected being in contact with an ear cartilage, the switching control unit  93040  does not feed the sound signal to the cartilage conduction equalizer  93138  even in the normal call mode, and thus the right and left drive units  93035  and  93036  do not drive the right and left vibration sources  93025   b  and  93025   a . The aim is to prevent unnecessary and inadvertent vibration of the right and left vibration sources  93025   b  and  93025   a.    
     One-Hundred Eighty-Second Embodiment 
       FIG. 294  comprises perspective views related to a one-hundred eighty-second embodiment of the present invention, which is configured as a mobile telephone. The one-hundred eighty-second embodiment in  FIG. 294 , like the one-hundred eighty-first embodiment shown in  FIGS. 291 to 293 , is configured as a modular smartphone of which a component module is replaceable/interchangeable, and shares with it many features; accordingly, similar parts are identified by the same reference signs, and no overlapping description will be repeated. The one-hundred eighty-second embodiment in  FIG. 294  differs from the one-hundred eighty-first embodiment in the structure of the cartilage conduction module  94027 , and uses the same mobile telephone body  93001 . 
       FIG. 294(A)  shows a state before the cartilage conduction module  94027  is inserted in the slot  93001   a  in the mobile telephone body  93001 . As will be clear from  FIG. 294(A) , in the one-hundred eighty-second embodiment, a shared elastic-body cartilage conduction unit  94024  is provided at one end, and insertion in the slot  93001   a  with or without a 180-degree rotation permits the shared elastic-body cartilage conduction unit  94024  to be used for either of the right and left ears. The cartilage conduction module  94027  has, on its rear face, a right module-side contact unit  94027   a  used when the shared elastic-body cartilage conduction unit  94024  is inserted for use in right arrangement and a left module-side contact unit  94027   b  used when the shared elastic-body cartilage conduction unit  94024  is inserted for use in left arrangement.  FIG. 294(A)  shows a state before the shared elastic-body cartilage conduction unit  94024  is inserted for use in right arrangement. 
       FIG. 294(B)  shows a state of the cartilage conduction module  94027  in the middle of being inserted into the slot  93001   a  by being slid in from its left side; when the insertion is complete, the right module-side contact unit  94027   a  makes contact with the body-side contact unit  93001   b . In the insertion-completed state, the shared elastic-body cartilage conduction unit  94024  is located at the right end of the slot  93001   a , and functions as an elastic-body cartilage conduction unit for use in right arrangement. In this case, the left module-side contact unit  94027   b  is not used. At an early stage of insertion, the left module-side contact unit  94027   b , in a state with its array of a plurality of contacts rotated through 180 degrees, makes contact with the body-side contact unit  93001   b  temporarily. How this is dealt with will be described later. 
       FIG. 294(C)  shows a state of the cartilage conduction module  94027 , 180 degrees rotated from the state in  FIG. 294(A)  for use in left arrangement, in the middle of being inserted into the slot  93001   a  by being slid in from its left side. When the insertion is complete, the left module-side contact unit  94027   b  makes contact with the body-side contact unit  93001   b . In the insertion-completed state, the shared elastic-body cartilage conduction unit  94024  is located at the left end of the slot  93001   a , and functions as an elastic-body cartilage conduction unit for use in left arrangement. In this case, the right module-side contact unit  94027   a  is not used. As in the case in  FIG. 294(B) , also in the case in  FIG. 294(C) , at an early stage of insertion, the right module-side contact unit  94027   a , in a state with its array of a plurality of contacts rotated through 180 degrees, makes contact with the body-side contact unit  93001   b  temporarily. How this is dealt with will also be described later. In  FIG. 294(C) , the cartilage conduction module  94027  is rotated through 180 degrees from the state in  FIG. 294(A) , and thus the positions of the videophone speaker  93051  and the videophone inner camera  93017  are reversed. 
       FIG. 295  is a block diagram of the one-hundred eighty-second embodiment in the insertion-completed state following the state in  FIG. 294(B)  where the cartilage conduction module  94027  is being inserted into the slot  93001   a  for use in right arrangement. The same parts as in  FIG. 294  are identified by the same reference signs, and no overlapping description will be repeated unless necessary. In the block diagram in  FIG. 295 , such parts as find their counterparts in the block diagram of the one-hundred eighty-first embodiment in  FIG. 293  are identified by the same reference signs, and no overlapping description will be repeated unless necessary. 
     As will be clear from  FIG. 295 , in the one-hundred eighty-second embodiment, irrespective of which of the right and left module-side contact units  94027   a  and  94027   b  makes contact with the body-side contact unit  93001   b , the cartilage conduction module  94027  coordinates with the mobile telephone body  93001 . Specifically, the right and left module-side contact units  94027   a  and  94027   b  are both connected to the switching control unit  94040 , and feed the sound signal received from the incoming-call processing unit  212  in the mobile telephone body  93001  across the signal line  94040   a  or  94040   b  to the switching control unit  94040  via an improper connection protection unit  94070 . In response, the switching control unit  94040  feeds the sound signal to either the videophone speaker  93051  or the cartilage conduction equalizer  94138  while switching between them based on the call mode signal received across the signal line  94040   c  or  94040   d . In a case where, in response to a call mode signal indicating the normal call mode, the sound signal is fed to the cartilage conduction equalizer  94138 , irrespective of which of the right and left module-side contact units  94027   a  and  94027   b  makes contact with the body-side contact unit  93001   b , a shared vibration source  94025  in the shared elastic-body cartilage conduction unit  94024  is vibrated by a shared drive unit  94035 . 
     Moreover, irrespective of which of the right and left module-side contact units  94027   a  and  94027   b  makes contact with the body-side contact unit  93001   b , the image signal from the videophone inner camera  93017  is delivered via the body-side contact unit  93001   b  to the controller  239  in the mobile telephone body  93001 . However, in  FIG. 294(C) , where the left module-side contact unit  94027   b  makes contact, in contrast to  FIG. 294(A) , where the right module-side contact unit  94027   a  makes contact, the videophone inner camera  93017  is rotated through 180 degrees. Accordingly, when the image signal from the videophone inner camera  93017  is output via the left module-side contact unit  94027   b , it is output after having a signal indicating that the image signal is upside down added to it by an upside-down inversion signal adding unit  94017   a . In response, in the mobile telephone body  93001 , the image processing unit  53  performs processing for inverting the image signal upside down. Instead, a configuration is also possible where the image signal itself is subjected to upside-down inversion on a frame-by-frame basis in the upside-down signal adding unit  94017   a  and is then output via the left module-side contact unit  94027   b  so that no processing is needed in the mobile telephone body  93001 . 
     Next, the improper connection protection unit  94070  will be described. The improper connection protection unit  94070  serves to check whether or not all of the plurality of contacts in the right or left module-side contact unit  94027   a  or  94027   b  are connected in a proper sequence. Unless connection in a proper sequence is recognized, it cuts off connection between the right and left module-side contact units  94027   a  and  94027   b  and the switching control unit  94040 . This helps avoid inconveniences that would result from temporary contact of the wrong module-side contact with the body-side contact unit  93001   b  (in particular, contact with a power terminal) at an early stage of insertion. An improper connection protection unit may be provided in each of the right and left module-side contact units  94027   a  and  94027   b  so that, unless connection in a proper sequence is recognized in each of the module-side contact units, no electrical connection between the cartilage conduction module  94027  and the mobile telephone body  93001  is established at all. 
     One-Hundred Eighty-Third Embodiment 
       FIG. 296  comprises perspective views related to a one-hundred eighty-third embodiment of the present invention, which is configured as a mobile telephone. The one-hundred eighty-third embodiment in  FIG. 296 , like the one-hundred eighty-first and -second embodiments shown in  FIGS. 291 to 295 , is configured as a modular smartphone of which a component module is replaceable/interchangeable, and shares with them many features; accordingly, similar parts are identified by the same reference signs, and no overlapping description will be repeated. The one-hundred eighty-third embodiment in  FIG. 296  differs from the one-hundred eighty-first and -second embodiments in the structure of the cartilage conduction module, and uses the same mobile telephone body  93001 . 
       FIG. 296(A)  is a perspective view of a right-dedicated cartilage conduction module  95027 R and a left-dedicated cartilage conduction module  95027 L used in the one-hundred eighty-third embodiment. In the one-hundred eighty-third embodiment, as in the one-hundred eighty-second embodiment in  FIG. 294 , an elastic-body cartilage conduction unit is provided at only one end of a cartilage conduction module. This, however, is not shared for use in right and left arrangement; a right-dedicated cartilage conduction module  95027 R including only a right elastic-body cartilage conduction unit  94024  and a left-dedicated cartilage conduction  95027 L including only a left elastic-body cartilage conduction unit  93026  are prepared as products, so that a user can either purchase whichever is easier for him to use (depending on whether he hears with the right or left ear) and insert it in the mobile telephone body  93001 , or purchase both and use them interchangeably as necessary. A plurality of users can share the mobile telephone body  93001 , in which case the right- and left-dedicated cartilage conduction modules  95027 R and  95027 L can be used interchangeably among the users. The right- and left-dedicated cartilage conduction modules  95027 R and  95027 L in the one-hundred eighty-third embodiment are not used in a 180 degrees rotated state, and thus each have one right or left module-side contact unit  94027   a  and  94027   b.    
       FIG. 296(B)  shows a state of the right-dedicated cartilage conduction module  95027 R in the middle of being inserted into the slot  93001   a  by being slid in from its left side; when the insertion is complete, the right module-side contact unit  94027   a  makes contact with the body-side contact unit  93001   b . On the other hand,  FIG. 296(C)  shows a state of the left-dedicated cartilage conduction module  95027 L in the middle of being inserted into the slot  93001   a  by being slid in from its left side; when the insertion is complete, the left module-side contact unit  94027   b  makes contact with the body-side contact unit  93001   b.    
     One-Hundred Eighty-Fourth Embodiment 
       FIG. 297  comprises perspective views related to a one-hundred eighty-fourth embodiment of the present invention, which is configured as a mobile telephone. The one-hundred eighty-fourth embodiment in  FIG. 297 , like the one-hundred eighty-first to -third embodiments shown in  FIGS. 291 to 296 , is configured as a modular smartphone of which a component module is replaceable/interchangeable. In the one-hundred eighty-fourth embodiment, as in the one-hundred eighty-second embodiment in  FIG. 294 , a shared cartilage conduction unit is provided at one end, and this is shared for use in right and left arrangement by insertion into the slot  93001   a  with or without a 180-degree rotation. This embodiment thus shares many features with the one-hundred eighty-second embodiment; accordingly, similar parts are identified by the same reference signs, and no overlapping description will be repeated. The mobile telephone body  93001  is the same as in one-hundred eighty-first to -third embodiments. 
       FIG. 297(A)  shows a state before the cartilage conduction module  96027  is inserted in the slot  93001   a  in the mobile telephone body  93001 . The one-hundred eighty-fourth embodiment in  FIG. 297  differs from the one-hundred eighty-second embodiment in  FIG. 294  in that the shared cartilage conduction unit  96024  is formed of a rigid body. Accordingly, the shared cartilage conduction unit  96024  is supported on the cartilage conduction module  96027  via an elastic body  96065  that functions as a vibration isolation material and a cushioning material. This construction, as in the one-hundred eighty-first embodiment shown in  FIG. 292 , suppresses conduction of the vibration of the shared cartilage conduction unit  96024  to the videophone inner camera  96017  and the like, and prevents the cartilage conduction module  96027  form clattering inside the slot  93001   a  due to the vibration of a vibration source. That is, when the front side of the shared cartilage conduction unit  96024  is put on a cartilage around the ear canal entrance, the shared cartilage conduction unit  96024  is pressed against the inner face of the slot  93001   a  via the elastic body  96065 , and this prevents clattering; in addition, the inner face of the slot  93001   a  via the elastic body  96065  provides a support when the shared cartilage conduction unit  96024  is put on the cartilage around the ear canal entrance. 
     Moreover, in the one-hundred eighty-fourth embodiment, as will be clear from  FIG. 297(A) , the videophone inner camera  96017  is disposed near an end part opposite from the shared cartilage conduction unit  96024 , as far away as possible from it, and this arrangement too makes it difficult for the vibration of the shared cartilage conduction unit  96024  to conduct to the videophone inner camera  96017  and the like. As in the one-hundred eighty-second embodiment in  FIG. 294 , the videophone speaker  96051  is disposed between the videophone inner camera  96017  and the shared cartilage conduction unit  96024 . This arrangement too contributes to making it difficult for the vibration of the shared cartilage conduction unit  96024  to conduct to the videophone inner camera  96017  and the like. 
       FIG. 297(B)  shows a state of the cartilage conduction module  96027  in the middle of being inserted into the slot  93001   a  by being slid in from its left side; when the insertion is complete, the right module-side contact unit  94027   a  makes contact with the body-side contact unit  93001   b . On the other hand,  FIG. 297(C)  shows a state of the cartilage conduction module  96027 , 180 degrees rotated from the state in  FIG. 297(A)  for use in left arrangement, in the middle of being inserted into the slot  93001   a  by being slid in from its left side; when the insertion is complete, the left module-side contact unit  94027   b  makes contact with the body-side contact unit  93001   b . This is common with the one-hundred eighty-second embodiment described with reference to  FIGS. 294 and 295 ; in other respects, this embodiment shares features with the one-hundred eighty-second embodiment, and therefore no overlapping description will be repeated. 
     One-Hundred Eighty-Fifth Embodiment 
       FIG. 298  comprises a perspective view and cross-sectional views related to a one-hundred eighty-fifth embodiment of the present invention, which is configured as a mobile telephone. The one-hundred eighty-fifth embodiment in  FIG. 298 , like the one-hundred eighty-first to -fourth embodiments shown in  FIGS. 291 to 297 , is configured as a modular smartphone of which a component module is replaceable/interchangeable. The mobile telephone body  93001  is the same as in the one-hundred eighty-first to -fourth embodiments. The one-hundred eighty-fifth embodiment differs from the one-hundred eighty-first to -fourth embodiments in that a cartilage conduction unit extends across the entire cartilage conduction module  97027  in its lengthwise direction so that, when the cartilage conduction module  97027  is inserted in the slot  93001   a , cartilage conduction is obtained with, not only either of top corner parts, but also any part of the top face of the mobile telephone put on an ear cartilage. 
       FIGS. 298(A) and 298(B)  are cross-sectional views of the cartilage conduction module  97027  in the mobile telephone of which the entirety is shown in the perspective view in  FIG. 298(C) . First,  FIG. 298(C)  will be referred to.  FIG. 298(C)  shows a state in which the cartilage conduction module  97027  is inserted in the slot  93001   a  in the mobile telephone body  93001 . As will be clear from  FIG. 298(C) , in the one-hundred eighty-fifth embodiment, the cartilage conduction module  97027  is so structured that an entire upper front part of it is an elastic-body cartilage conduction unit  97024  and, as will be described later, the vibration of a vibration source conducts to the entire elastic-body cartilage conduction unit  97024 . In the one-hundred eighty-fifth embodiment, the videophone inner camera  93017  and the videophone speaker  93051  are disposed in a lower part of a middle part of the front face of the cartilage conduction module  97027 . 
       FIG. 298(A)  is a cross-sectional view of the cartilage conduction module  97027  in  FIG. 298(C)  along line A-A. As will be clear from  FIG. 298(A) , The elastic-body cartilage conduction unit  97024  is lined with a vibration conducting plate  97024   a  which is a rigid body; further on the rear side of the vibration conducting plate  97024   a , a vibration source  97025  is supported, of which the vibration is conducted to the entire vibration conducting plate  97024   a  efficiently. The vibration conducting plate  97024   a  and the vibration source  97025  are supported solely by the elastic-body cartilage conduction unit  97024 , and does not make contact with the casing part of the cartilage conduction module  97027 , which is a rigid body structure. Thus, the difference in acoustic impedance between the elastic-body cartilage conduction unit  97024  and the cartilage conduction module  97027  suppresses the conduction of the vibration from the vibration source  97025  and the vibration conducting plate  97024   a  to the videophone inner camera  93017  and the videophone speaker  93051  supported on the rigid body structure of the cartilage conduction module  97027 . Accordingly, the clattering of the cartilage conduction module  97027  is alleviated. 
       FIG. 298(B)  is a cross-sectional view of the cartilage conduction module  97027  in  FIG. 298(C)  along line B-B (a cross-sectional view including the vibration conducting plate  97024   a ). Also from  FIG. 298(B) , it is seen that the vibration conducting plate  97024   a  is supported solely by the elastic-body cartilage conduction unit  97024 , and does not make contact with the casing part of the cartilage conduction module  97027 , which is a rigid body structure. 
     The features of the present invention in the embodiments described above are not limited to those embodiments, but may be implemented in any other embodiments so long as they offer their benefits. For example, the arrangement of the videophone inner camera in an end part of the cartilage conduction module in the one-hundred eighty-fourth embodiment in  FIG. 297  can be adopted in the one-hundred eighty-second embodiment in  FIG. 294  or in the one-hundred eighty-third embodiment in  FIG. 296 . For another example, the arrangement of the videophone speaker  96051  being disposed between the videophone inner camera  96017  and the shared cartilage conduction unit  96024  in the one-hundred eighty-fourth embodiment in  FIG. 297  can be adopted in the left-dedicated cartilage conduction module  95027 L in the one-hundred eighty-third embodiment in  FIG. 296 . 
     In the embodiments shown in  FIGS. 291 to 298 , any element other than a cartilage conduction unit and elements related to it may be omitted from a cartilage conduction module as necessary; instead, any other element (for example, a proximity detection unit) may be added to a cartilage conduction module as necessary. If necessary for a cartilage conduction unit to perform its function, it may be provided with a power step-up means or a dedicated power supply as necessary. 
     One-Hundred Eighty-Sixth Embodiment 
       FIG. 299  is a front view related to a one-hundred eighty-sixth embodiment of the present invention, which is configured as a mobile telephone  98001  and an ear-hole hearing aid  98081  that coordinate with each other.  FIG. 299  is a front view showing a state where the ear-hole hearing aid  98081  is worn on the right ear  28 , as seen from the right ear  28 -side, and there the coordinating mobile telephone  98001  is indicated by dash-and-dot lines. The mobile telephone  98001  includes, in opposite corners of a top part of it, a right-ear cartilage conduction unit  98024  and a left-ear cartilage conduction unit  98026 , of which either is put into contact with a cartilage (for example, the tragus) at the ear canal entrance of the right ear  28  or the left ear (unillustrated). Other details are as described in connection with other embodiments, and therefore no overlapping description will be repeated. The mobile telephone  98001  of the one-hundred eighty-sixth embodiment can be used in a regular way as described above, and can also be coordinated with the ear-hole hearing aid  98081 . Specifically, as shown in  FIG. 299 , the right-ear cartilage conduction unit  98024  of the mobile telephone  98001  is put into contact with the ear-hole hearing aid  98081  on top of it in a state worn on the right ear  28 . 
     Thus, the vibration of the right-ear cartilage conduction unit  98024  is conducted to the ear-hole hearing aid  98081 , and the vibration is conducted further to the ear cartilage at the ear canal entrance of the right ear  28  on which the ear-hole hearing aid  98081  is worn. Thus having the vibration conducted to it, the ear cartilage generates air-conduction sound inside the ear cartilage of the right ear  28 , and the air-conduction sound then reaches the eardrum, so that sound based on the sound source in the mobile telephone  98001  is heard. Thus, the phenomena that take place after the vibration has reached the ear cartilage of the right ear  28  are the same as in the ordinary case where the right-ear cartilage conduction unit  98024  is put in direct contact with the ear cartilage around the ear canal. 
     As described above, by putting the right-ear cartilage conduction unit  98024  (or the left-ear cartilage conduction unit  98026 ) of the mobile telephone  98001  in contact with the ear-hole hearing aid  98081  (hereinafter referred to simply as the hearing aid  98081 ) and thereby vibrating the hearing aid  98081 , its vibration conducts to the ear cartilage around the hearing aid  98081  and generates air-conduction sound inside the ear canal—thus much has already been described in connection with the fifty-fifth embodiment shown in  FIGS. 83 to 85 . The one-hundred eighty-sixth embodiment described below with reference to  FIG. 299  and the following drawings is directed to coordination between the hearing aid  98081  and the mobile telephone  98001  that takes place when a call is conducted by cartilage conduction while vibration from the mobile telephone  98001  is conducted to the hearing aid  98081 . 
       FIG. 300  is a cross-sectional view of the one-hundred eighty-sixth embodiment in  FIG. 299 . A casing  98081   a  of the hearing aid  98081  has an acoustically integral structure to allow good conduction of vibration from a part making contact with the mobile telephone  98001  to a part inserted into the ear canal entrance  30   a . The part of the casing  98081   a  making contact with the mobile telephone  98001  is covered with an elastic-material coating  98081   b  for preventing clattering resulting from contact. When the hearing aid  98081  functions as an ordinary hearing aid, it outputs, under the control of a control unit  98039 , the sound collected by a microphone  98022  from an air-conduction sound speaker  98027 . Thus, from the air-conduction sound speaker  98027 , air-conduction sound is generated as indicated by a broken-line arrow, and it then travels on inside the ear canal to reach the eardrum. 
     The hearing aid  98081  also includes an NFC tag  98037  conforming to an NFC (near-field communication) non-contact communication system such as FeliCa (a registered trademark). The NFC tag  98037  stores a hearing aid ID which identifies the hearing aid  98081 , a user ID which identifies the user who is using the hearing aid  98081 , a customization ID which identifies hearing-aid customization settings, which will be described later, and maintenance information such as adjustment data. The NFC tag  98037  is used in identifying and maintaining the hearing aid  98081  and, as described later, is also used in coordination with the mobile telephone  98001 . 
     When a call is conducted on the mobile telephone  98001  with the hearing aid  98081  worn on an ear (for example, the right ear), then, as shown in  FIG. 300 , without the hearing aid  98081  being removed, that is, on top of the hearing aid  98081 , the right-ear cartilage conduction unit  98024  of the mobile telephone  98001  is pressed against the elastic-material coating  98081   b  of the hearing aid  98081 . Thus, the vibration generated by the vibration source  98025  is first conducted from the right-ear cartilage conduction unit  98024  to the casing  98081   a  of the hearing aid  98081 , and is then conducted further from the casing  98081   a  to the ear cartilage at the ear canal entrance  30   a  of the right ear. Then the vibrating ear cartilage at the ear canal entrance  30   a  generates air-conduction sound inside the ear canal, and the air-conduction sound reaches the eardrum. This series of acoustic phenomena is indicated by solid-line arrows. 
     The hearing aid  98081  includes a vibration detection unit  98042 . When it is detected that vibration from the mobile telephone  98001  has started conducting, under the control of the control unit  98039 , the microphone  98022  and the air-conduction sound speaker  98027  are turned off. The function as an ordinary hearing aid is thus stopped, and the hearing aid  98081  functions as a vibration conduction path from the mobile telephone  98001  to the ear cartilage at the ear canal entrance  30   a . On the other hand, when a predetermined period has elapsed since, as a result of the mobile telephone  98001  being taken apart from the hearing aid  98081 , the vibration detection unit  98042  ceased to detect vibration, under the control of the control unit  98039 , the microphone  98022  and the air-conduction sound speaker  98027  are turned on. Thus, the function as an ordinary hearing aid is restored. The aim of setting the just-mentioned predetermined period is to prevent the microphone  98022  and the air-conduction sound speaker  98027  from turning on and off at short time intervals in response to the vibration detection unit  98042  not detecting vibration temporarily in a voiceless period during a call. As necessary, the microphone  98022  and the air-conduction sound speaker  98027  can be turned on forcibly by manual operation. 
       FIG. 301  is a block diagram of the mobile telephone  98001  of the one-hundred eighty-sixth embodiment. The same parts as in  FIG. 300  are identified by the same reference signs, and no overlapping description will be repeated unless necessary. The block diagram in  FIG. 301  has much in common with the block diagram of the one-hundred fifty-first embodiment in  FIG. 240 ; accordingly, common parts are identified by the same reference signs, and no overlapping description will be repeated unless necessary. The following description discusses parts involved in coordination with the hearing aid  98081 . 
     The mobile telephone  98001  includes a hearing-aid customization setting unit  98089  which allows previous setting of customized equalization that suits the hearing characteristics of the user of the mobile telephone  98001 . As will be described later, the hearing aid  98081  has been equalized to suit the user&#39;s hearing characteristics; when vibration from the mobile telephone  98001  is conducted to it, the inherent function of the hearing aid  98081  is stopped. Thus, to permit sound that suits the user&#39;s hearing characteristics to be conducted even when a call is conducted using the mobile telephone  98001 , the vibration source  98025  is vibrated using data in the hearing-aid customization setting unit  98089 . The data reflects the customization settings in the hearing aid  98081 . The function of the hearing-aid customization setting unit  98089  will be described in detail later. In the hearing-aid customization setting unit  98089 , different sets of equalization data for a plurality of persons based on different hearing aids can be set and stored. Whose equalization data a particular set is can be identified by the user ID. 
     The mobile telephone  98001  also includes an NFC tag reader  98046  for communication with the NFC tag  98037  in the hearing aid  98081 . The NFC tag reader  98046  has two functions. The first function is to identify, among the equalization data set in the hearing-aid customization setting unit  98089 , the data to be used according to the user ID in the NFC tag  98037  read by contact with the hearing aid  98081 . The second function is to switch whether to vibrate the vibration source  98025  for ordinary cartilage conduction or for conduction to the hearing aid  98081 . Specifically, when the NFC tag reader  98046  succeeds in reading the data in the NFC tag  98037 , it is judged that the mobile telephone  98001  and the hearing aid  98081  are in contact with each other, and the vibration source  98025  is vibrated for conduction to the hearing aid  98081 . On the other hand, when the NFC tag reader  98046  cannot read the data in the NFC tag  98037 , it is judged that the mobile telephone  98001  and the hearing aid  98081  are out of contact with each other, and the vibration source  98025  is vibrated for ordinary cartilage conduction. 
     For the above-mentioned purpose, when the NFC tag reader  98046  succeeds in reading the data in the NFC tag  98037 , the control unit  57039  controls an equalization switcher  98038  to switch to equalization using the equalization data identified among what is set in the hearing-aid customization setting unit  98089 . On the other hand, when the NFC tag reader  98046  cannot read the data in the NFC tag  98037 , the control unit  57039  controls the equalization switcher  98038  to switch to equalization for ordinary cartilage conduction. 
     Since the hearing aid  98081  closes the ear canal entrance  30   a , it is used, during cartilage conduction for conducting vibration from the mobile telephone  98001 , in a closed ear canal state (occluded external auditory meatus state). Accordingly, when the NFC tag reader  98046  succeeds in reading the data in the NFC tag  98037 , the control unit  57039  controls a phase adjustment mixer  236  to mix a self-voice inversion sound signal from a waveform inverter  240 . Thus, the user&#39;s voice as collected by a microphone  223  in the mobile telephone  98001  and conducted from the cartilage-conduction vibration source  98025  cancels out, inside the ear canal, the user&#39;s live voice as conducted as it is from the cranium, and this alleviates the feeling of strangeness to the user&#39;s own voice. On the other hand, when the NFC tag reader  98046  cannot read the data in the NFC tag  98037 , the control unit  57039  controls the phase adjustment mixer  236  based on ordinary cartilage conduction as explained in connection with other embodiments. A driver  98040  comprising an amplifier or the like drives the cartilage-conduction vibration source  98025  based on an output that has undergone the sound signal processing by the phase adjustment mixer  236  and the equalization switcher  98038 . As necessary, an operation unit  9  is operated manually to vibrate the cartilage-conduction vibration source  98025  forcibly for ordinary cartilage conduction. A power supply unit  1448  includes a rechargeable battery and the like, and supplies the entire mobile telephone  98001  with electric power. 
       FIG. 302  is a flow chart of the operation of the control unit  57039  in the mobile telephone  98001  in the one-hundred eighty-sixth embodiment in  FIG. 301 . The flow in  FIG. 302  is directed chiefly to coordination with the hearing aid  98081 , and therefore it focuses on relevant operation in an extracted manner; that is, there is other operation of the control unit  57039  that does not appear in the flow in  FIG. 302 , such as operation for regular functions of a mobile telephone. The flow in  FIG. 302  starts when the main power to the mobile telephone  98001  is turned on. At step S 1252 , it is checked whether or not a normal mode for performing ordinary cartilage conduction is selected. 
     If, at step S 1252 , the normal mode is not found to be selected, it means that an automatic switching mode assuming coordination with the hearing aid  98081  is selected; accordingly, an advance is made to step S 1254 , where it is checked whether or not the NFC tag  98037  can be read. If it can be read, an advance is made to step S 1256 , where the user ID is read from the NFC tag  98037 . Then, based on the user ID read, the equalization data that is set for the corresponding user is read from the hearing-aid customization setting unit  98089 , and an advance is made to step S 1258 , where switching to customized equalization based on the data is performed. Subsequently, at step S 1260 , waveform inversion self-voice mixing is performed by the phase adjustment mixer  236 , and an advance is made to step S 1262 . 
     At step S 1262 , following the process thus far, hearing aid-oriented mobile telephone operation is started, and an advance is made to step S 1264 . At step S 1262 , it is checked whether or not timing for a check for the necessity of mode switching and automatic switching has arrived; if it has not arrived yet, a return is made to step S 1262 , where hearing aid-oriented mobile telephone operation is continued. Thereafter, unless the check timing is found to have arrived at step S 1264 , hearing aid-oriented mobile telephone operation is performed while steps S 1262  and S 1264  are repeated. On the other hand, if, at step S 1264 , the check timing is found to have arrived, an advance is made to step S 1266 . 
     In contrast to the operation above, if, at step S 1252 , the normal mode is found to have been selected, an advance is made to step S 1268 . When the normal mode is selected, coordination with the hearing aid  98081  is stopped forcibly. Step S 1258  is also useful as a function for returning to the normal mode manually in emergency. On the other hand, if, at step S 1254 , it is found that the NFC tag  98037  cannot be read, it is judged that the mobile telephone  98001  and the hearing aid  98081  are out of contact with each other, and also in this case, an advance is made to step S 1268 . At step S 1268 , switching to ordinary cartilage conduction equalization is performed, and an advance is made to step S 1270 . 
     At step S 1270 , following the process thus far, mobile telephone operation relying on ordinary cartilage conduction is started, and an advance is made to step S 1272 . At step S 1272 , it is checked whether or not timing for a check for mode switching has arrived, and if it has not arrived yet, a return is made to step S 1270 , where ordinary mobile telephone operation is continued. Thereafter, unless the check timing is found to have arrived at step S 1272 , ordinary mobile telephone operation is performed while steps S 1270  and S 1272  are repeated. On the other hand, if, at step S 1272 , the check timing is found to have arrived, an advance is made to step S 1266 . 
     At step S 1266 , it is checked whether or not an operation to turn off the power to the mobile telephone  98001  has been done, and if no operation to turn off the power has been done, a return is made to step S 1252 . Thereafter, until an operation to turn off the power is detected at step S 1266 , steps S 1252  through S 1272  are repeated to cope with mode switching and changes in whether the NFC tag can or cannot be read. 
       FIG. 303  is a block diagram related to the hearing aid  98081  of the one-hundred eighty-sixth embodiment. The same parts as in  FIG. 300  are identified by the same reference signs, and no overlapping description will be repeated unless necessary. The control unit  98039  performs ordinary hearing-aid functions based on programs stored in a storage unit  98037   a  in coordination with a hearing-aid function unit  98045 . One main function is to output the sound collected by the microphone  98022  from the air-conduction sound speaker  98027 . A customization setting unit  98090  performs customization setting for equalizing the sound collected by the microphone  98022  to suit the user&#39;s hearing characteristics then outputting it from the air-conduction sound speaker  98027 , and memorizes the results. 
     Chief functions for coordination with the mobile telephone  98001  have been described with reference to  FIG. 300 , and therefore no overlapping description will be repeated. As necessary, the operation unit  98009  is used to turn on the microphone  98022  and the air-conduction sound speaker  98027  forcibly by manual operation. A power supply unit  98047  includes a replaceable battery or the like, and supplies the entire hearing aid  98081  with electric power. 
       FIG. 304  is a flow chart of the operation of the control unit  98039  in the hearing aid  98081  in the one-hundred eighty-sixth embodiment in  FIG. 301 . The flow in  FIG. 304  is directed chiefly to coordination with the mobile telephone  98001 , and therefore it focuses on relevant operation in an extracted manner; that is, there is other operation of the control unit  98039  that does not appear in the flow in  FIG. 304 , such as operation for regular functions of a hearing aid. The flow in  FIG. 304  starts when a battery is set in the power supply unit  98047  in the hearing aid  98081  or the main power to it is turned on. At step S 1282 , it is checked whether or not a normal mode for ordinary hearing-aid control is selected. 
     If, at step S 1282 , the normal mode is not found to be selected, it means that an automatic switching mode assuming coordination with the mobile telephone  98001  is selected; accordingly, an advance is made to step S 1284 , where it is checked whether or not vibration conducted from the mobile telephone  98001  is detected. If vibration is detected, an advance is made to step S 1286 , where the microphone  98022  and the air-conduction sound speaker  98027  of the hearing aid  98081  are turned off, and an advance is made to step S 1288 . At step S 1288 , it is checked whether or not timing for a check for the necessity of mode switching and automatic switching has arrived, and if it has not arrived yet, a return is made to step S 1286 , where a call relying on vibration conducted from the mobile telephone  98001  is continued. Thereafter, unless the check timing is found to have arrived at step S 1288 , the call relying on vibration conducted from the mobile telephone  98001  is performed while steps S 1286  and S 1288  are repeated. On the other hand, if, at step S 1288 , the check timing is found to have arrived, an advance is made to step S 1290 . 
     In contrast to the operation above, if, at step S 1282 , the normal mode is found to have been selected, an advance is made to step S 1292 . If the normal mode is selected, as will be described later, the function as a hearing aid is maintained forcibly. Step S 1282  is also useful for returning to the normal mode manually in emergency. On the other hand, if, at step S 1284 , vibration ceases to be detected, an advance is made to step S 1294 , where it is checked whether or not a predetermined period has elapsed. If the predetermined period has not elapsed, a return is made to step S 1284 , and thereafter, unless vibration is detected at step S 1284  or the predetermined period has elapsed at step S 1294 , steps S 1284  and S 1294  are repeated. When, at step S 1294 , the predetermined time is detected to have elapsed, an advance is made to step S 1292 . 
     At step S 1292 , the microphone  98022  and the air-conduction sound speaker  98027  of the hearing aid  98081  are turned on, and an advance is made to step S 1296 . At step S 1296 , following the process thus far, ordinary hearing-aid operation is started, and an advance is made to step S 1298 . As step S 1298 , it is checked whether or not timing for a check for mode switching has arrived, and if it has not arrived yet, a return is made to step S 1296 , where ordinary hearing-aid operation is continued. Thereafter, unless the check timing is found to have arrived at step S 1298 , ordinary hearing-aid operation is performed while steps S 1296  and S 1298  are repeated. On the other hand, if, at step S 1298 , the check timing is found to have arrived, an advance is made to step S 1290 . 
     At step S 1290 , it is checked whether or not an operation to turn off the power to the hearing aid  98081  has been done, and if no operation to turn off the power has been done, a return is made to step S 1282 . Thereafter, until an operation to turn off the power is detected at step S 1290 , steps S 1282  through step S 1298  are repeated to cope with mode switching and changes in whether or not vibration is detected. 
     One-Hundred Eighty-Seventh Embodiment 
       FIG. 305  is a front view related to a one-hundred eighty-seventh embodiment of the present invention, which is configured as a mobile telephone  98001  and an ear-hook hearing aid  99081  that coordinate with each other. Like  FIG. 299  showing the one-hundred eighty-sixth embodiment,  FIG. 305  is a front view of the ear-hook hearing aid  99081  in a worn state as see from the right ear  28  side, and the coordinating mobile telephone  98001  is indicated by dash-and-dot lines. The mobile telephone  98001  is the same as the one shown in  FIG. 299 , and therefore no detailed description will be repeated. Also in the one-hundred eighty-seventh embodiment, normally, one of top corner parts of the mobile telephone  98001  is put into contact with the ear cartilage at the ear canal entrance of the right ear  28  or the left ear (unillustrated). Also the mobile telephone  98001  of the one-hundred eighty-seventh embodiment can be used in an ordinary way as described above or be coordinated with the ear-hook hearing aid  99081 . 
     Specifically, as shown in  FIG. 305 , the ear-hook hearing aid  99081  is worn with an ear hook part  99081   a  hooked on an ear  28  (at the back of the auricle) and with an insertion part  99081   b  inserted in the ear canal entrance. In this worn state, a right-ear cartilage conduction unit  98024  of the mobile telephone  98001  is put into contact with it on top the insertion part  99081   b . Thus, vibration of the right-ear cartilage conduction unit  98024  is conducted to the insertion part  99081   b  of the ear-hook hearing aid  99081 , and the vibration is conducted further to the cartilage at the ear canal entrance of the right ear  28  in which the insertion part  99081   b  is inserted. Thus having the vibration conducted to it, the ear cartilage generates air-conduction sound inside the ear canal of the right ear  28 , and the air-conduction sound reaches the eardrum, so that sound based on the sound source in the mobile telephone  98001  is heard. 
     Of the insertion part  99081   b  of the ear-hook hearing aid  99081  in the one-hundred eighty-seventh embodiment, a casing part from a part making contact with the mobile telephone  98001  to a part inserted into the ear canal entrance has an acoustically integral structure to allow good conduction of vibration. This is similar to the integral structure of the casing part of the ear-hole hearing aid  98081  of the one-hundred eighty-sixth embodiment. Also similar to the one-hundred eighty-sixth embodiment is that a part of the insertion part  99081   b  that makes contact with the mobile telephone  98081  is coated with an elastic-material coating for preventing clattering resulting from contact. Also similar to the ear-hole hearing aid  98001  of the one-hundred eighty-sixth embodiment is that an NFC tag is provided in the insertion part  99081   b  of the ear-hook hearing aid  99081 . In other respects, the configuration, and also the control related to coordination between the hearing aid and the mobile telephone, in the one-hundred eighty-seventh embodiment is substantially common with the one-hundred eighty-sixth embodiment, and therefore no further description will be given. 
     The present invention can be implemented in any other manners than in the embodiments described above, and its many benefits are obtained in any other embodiments. Moreover, the features described above can be implemented in interchanged or combined manners among different embodiments. For example, although, in the one-hundred eighty-sixth embodiment shown in  FIGS. 299 to 305  and the one-hundred eighty-seventh embodiment shown in  FIG. 305 , the hearing aid includes an NFC tag, its benefit is not limited to those embodiments but is useful in the hearing aid on its own or in various forms of coordination between the hearing aid and the mobile telephone. For example, writing customization information for different users of the hearing aid to the NFC tag is extremely useful in maintenance, adjustment, and the like of the hearing aid. In an embodiment where a mobile telephone having an ordinary air-conduction sound speaker is put on an ear with a hearing aid kept worn on it so that a microphone in the hearing aid collects the air-conduction sound from the mobile telephone, it is possible, in response to an NFC tag in the hearing aid becoming readable, to perform automatic adjustment so that the sound volume of the air-conduction sound speaker of the mobile telephone and the equalization for driving it suit the condition of hearing via the hearing aid as described above. In a case where a hearing aid including a T coil is provided with an NFC tag, it is possible, in response to the NFC tag in the hearing aid becoming readable, to automatically turn on the T coil function of a mobile telephone. 
     In the present description, “cartilage conduction” is a registered trademark. 
     SUMMARY 
     The following is a description summarizing the various embodiment that have been disclosed in the present specification. 
     &lt;First Technical Feature&gt; 
     A first technical feature disclosed in the present specification provides a mobile telephone in which the upper part of the mobile telephone is provided with a cartilage conduction vibration unit that makes contact with ear cartilage. It is thereby possible to provide a mobile telephone which makes use of the excellent performance exhibited by ear cartilage in regard to transmitting audio information, and which can be used without a sense of discomfort from pressure or insertion into the ear, the user experience being similar to that of the normal state of a telephone call. 
     According to a specific feature, the cartilage conduction vibration unit is configured so as not to protrude from the outer wall of the mobile telephone. It is thereby possible to achieve a shape whose absence of awkward protruding parts caused by the arrangement of the cartilage conduction vibration unit compromises neither the function nor the aesthetics of the mobile telephone. 
     According to a more specific feature, the cartilage conduction vibration unit is arranged at an upper part corner on the ear side of the mobile telephone. It is thereby possible to achieve an arrangement where the cartilage conduction vibration unit does not protrude from the outer wall of the mobile telephone, by which natural contact with the ear cartilage can be realized. 
     According to an even more specific feature, the cartilage conduction vibration unit is arranged on one of the upper part corners on the ear side of the mobile telephone that faces diagonally downward in the usage posture. It is thereby possible for the cartilage conduction vibration unit to be brought into contact with the ear cartilage in a state that is awkward neither to the person making the telephone call nor to onlookers, due to the posture approximating the normal state of a telephone call, in which the mobile telephone is held by hand and brought up against the ear. Such a posture is doubly suitable, due to being suitable for making contact with the tragus and due to the tragus being particularly highly effective in terms of cartilage conduction. 
     According to another specific feature, there are two of the cartilage conduction vibration units provided to the upper part of the mobile telephone. Such a configuration is suitable by virtue of there being more effective contact with the ear cartilage. The two cartilage conduction vibration units can, for example, be configured such that one is made to vibrate in accordance with whether the right ear or the left ear is being used, thus providing support for switching between holding with the left and right hand. 
     According to a further specific feature, a sensor for detecting which of the two cartilage conduction vibration units is in contact with the ear is provided to the upper part of the mobile telephone, and one of the two cartilage conduction vibration units is made to vibrate in accordance with the output of the sensor. Alternatively, a gravitational acceleration detection unit is instead provided, one of the two cartilage conduction vibration units being made to vibrate in accordance with the direction of gravitational acceleration detected by the gravitational acceleration detection unit. The elements described above may also be used concurrently to detect when the hand holding the mobile telephone is switched. 
     According to another feature, in a mobile telephone having a videoconferencing function, the functions of the cartilage conduction vibration unit are prohibited whenever the videoconferencing function is in operation. The cartilage conduction vibration unit can thereby be prevented from functioning without purpose in the state where the mobile telephone is not to be brought up against the ear. 
     According to yet another feature, a folding structure is included, the functions of the cartilage conduction vibration unit being prohibited in a folded state in a case where the cartilage conduction vibration unit is arranged at a position at which contact with the ear cartilage becomes impossible in the folded state. The cartilage conduction vibration unit can thereby be prevented from functioning without purpose in the state where the mobile telephone cannot be held up against the ear. 
     According to another feature, there is provided an audio output device, comprising: an audio output unit; a controller for simultaneously outputting audio information to the audio output unit and the cartilage conduction vibration unit; and a phase adjustment unit for phase-adjusting the phase of an audio signal being outputted to the audio output unit and the cartilage conduction vibration unit. It is thereby possible to prevent the adverse event caused when the same audio information is transmitted by two systems, i.e., bone conduction and air vibration from the external auditory meatus. 
     According to another feature, there is provided an audio output device, comprising: a bone conduction vibration unit, an environment noise microphone; and a phase adjustment unit for inverting the phase of, and then outputting to the cartilage conduction vibration unit, audio information that has been picked up by the environment noise microphone. It thereby becomes possible to cancel out the environment noise from the environment noise and useful audio information conducted by air vibration from the external auditory meatus. 
     &lt;Second Technical Feature&gt; 
     A second technical feature disclosed in the present specification provides a mobile telephone having cartilage conduction vibration unit, which includes a cartilage conduction vibration source, as well as a cartilage conductor for guiding the vibration of the cartilage conduction vibration source to the upper part of the mobile telephone in contact with the ear cartilage. It is thereby possible to provide a mobile telephone that makes use of the excellent performance exhibited by ear cartilage in regard to transmitting audio information, and which can be used without a sense of discomfort from pressure or insertion into the ear, the user experience approximating that of the normal state of a telephone call. Furthermore, according to the configuration of the cartilage conduction vibration unit described above, the vibration of the cartilage conduction vibration source is guided by the cartilage conductor to a desired position, which is advantageous in that a greater amount of freedom is provided for the layout of the cartilage conduction vibration source itself and in that the cartilage conduction vibration unit can be installed on a mobile telephone lacking any available extra space. 
     According to a specific feature, the cartilage conduction vibration source and the cartilage conductor are configured so as not to protrude from an outer wall of the mobile telephone. It is thereby possible to achieve a shape whose absence of awkward protruding parts caused by the arrangement of the cartilage conduction vibration unit compromises neither the function nor the aesthetics of the mobile telephone. According to an even more specific feature, the end part of the cartilage conductor is arranged at an upper part corner of the ear side of the mobile telephone. It is thereby possible to achieve an arrangement where the cartilage conduction vibration units do not protrude from the outer wall of the mobile telephone, by which a natural contact with the ear cartilage can be realized. According to a further specific feature, the end part of the cartilage conductor is arranged on one of the upper part corners on the ear side of the mobile telephone that faces diagonally downward during the usage posture. It is thereby possible for the cartilage conduction vibration unit to be brought into contact with the ear cartilage in a state that is awkward neither to the person making the telephone call nor to onlookers, due to the posture approximating the normal state of a telephone call, in which the mobile telephone is held by hand and brought up against the ear. Such a posture is doubly suitable, because it is suitable for contact with the tragus and also because the tragus is particularly highly effective in terms of cartilage conduction. 
     According to another specific feature, the two ends of the end parts of the cartilage conductor are arranged at both corners of the upper part on the ear side of the mobile telephone. Such a configuration is suitable by virtue of there being more effective contact with the ear cartilage. One of the two ends of the end parts of the cartilage conductor can, for example, be brought into contact with the ear cartilage as appropriate, in accordance with whether the right ear or the left ear is being used, thus providing support for readily switching between holding the mobile telephone with the left and right hand. 
     According to another feature, there is provided a mobile telephone comprising: a cartilage conduction vibration unit brought into contact with ear cartilage; a gravitational acceleration detection unit; and a controller for prohibiting the cartilage conduction vibration unit from vibrating whenever the gravitational acceleration detection unit detects that the mobile telephone is in a stationary state. It is thereby possible to prevent the cartilage conduction vibration unit from uselessly vibrating and generating a distracting sound when, for example, the mobile telephone is placed on a desk or the like with the cartilage conduction vibration unit facing down. 
     According to a specific feature, the mobile telephone includes a sensor for detecting the presence or absence of an object in proximity with the cartilage conduction vibration unit, where the controller causes the cartilage conduction vibration unit to vibrate in accordance with whether the sensor detects an object in proximity, and prohibits the cartilage conduction vibration unit from vibration, irrespective of whether the sensor detects an object in proximity, whenever the gravitational acceleration detection unit detects that the mobile telephone is in a stationary state. The sensor for detecting the presence or absence of an object in proximity is a useful configuration for detecting when the mobile telephone has been brought up against the ear and causing the cartilage conduction vibration unit to vibrate, but when, for example, the mobile telephone has been placed on a desk or the like, there is the potential for this state to be falsely confirmed as contact to the ear and for the cartilage conduction vibration unit to be made to vibrate. Herein, the aforesaid specific feature can prevent the generation of uncomfortable sound due to the vibration of the cartilage conduction vibration unit based on such false confirmation. 
     According to another feature, there is provided a mobile telephone comprising: a cartilage conduction vibration unit to be brought into contact with ear cartilage; an audio input unit; a phase inverter for phase-inverting audio information inputted from the audio input unit; and a controller for outputting, from the cartilage conduction vibration unit, the audio information having been phase-inverted by the phase inverter. It is thereby possible to appropriately minimize any discomfort based on one&#39;s own voice during a conversation by mobile telephone in the state where the cartilage conduction vibration unit has been brought into contact with the ear cartilage. 
     According to a specific feature, the mobile telephone includes an acoustics adjustment unit, where the controller outputs, from the cartilage conduction vibration unit, audio information that has been acoustically adjusted by the acoustics adjustment unit and also phase-inverted by the phase inverter. It is thereby possible to more appropriately minimize any discomfort that is based on one&#39;s own voice during a conversation by mobile telephone. 
     According to another specific feature, the mobile telephone includes a contact state detection unit for detecting the state where the cartilage conduction vibration unit is in contact with the ear cartilage, where the controller determines whether or not to output, from the cartilage conduction vibration unit, audio information that has been phase-inverted by the phase inverter in accordance with the state detected by the contact state detection unit. It is thereby possible to more appropriately control the discomfort that is based on one&#39;s own voice in accordance with the state where the mobile telephone is in contact with the ear cartilage. 
     According to a more specific feature, the contact state detection unit detects when the cartilage conduction vibration unit is in contact with the ear cartilage in the state where the ear hole is blocked by the mobile telephone being in contact with the ear cartilage, the earplug bone conduction effect thus occurring, where the controller outputs, from the cartilage conduction vibration unit, audio information that has been phase-inverted by the phase inverter in accordance with a detection that the cartilage conduction vibration unit is in contact with the ear cartilage in the state where the earplug bone conduction effect occurs. The earplug bone conduction effect, which occurs due to the ear hole being blocked, achieves a listening status with dual effects, in which audio information from the cartilage conduction vibration unit is conducted by even louder sound and in which environmental noise is obstructed. However, the earplug bone conduction effect is meanwhile accompanied by the discomfort of one&#39;s own voice through bone conduction from the vocal cords. The aforesaid feature is advantageous in attenuating such discomfort of one&#39;s own voice. 
     According to another feature, there is provided a piezoelectric element control device comprising: a conduction vibration unit that includes a piezoelectric element and transmits vibration of the piezoelectric element by being brought into contact with a body to which conduction is directed; a signal output unit for outputting conduction vibration information to the piezoelectric element; and a pressure detection unit for detecting, through the piezoelectric element, changes in the contact pressure between the conduction vibration unit and the body to which conduction is directed. By such a configuration, the piezoelectric element can serve a dual purpose as an output element for contact vibration and also as a contact pressure sensor, and conduction vibration can be outputted in accordance with a variety of circumstances. Such a piezoelectric element control device is configured as a mobile telephone, the body to which conduction is directed being the ear cartilage, and is suitable for detecting the state where the cartilage conduction vibration unit is in contact with the ear cartilage depending on the pressure changes sensed by the piezoelectric element. 
     &lt;Third Technical Feature&gt; 
     A third technical feature disclosed in the present specification provides a mobile telephone comprising a cartilage conduction vibration source and a conductor for guiding the vibration of the cartilage conduction vibration source to the ear cartilage, wherein the conductor is an elastic body. It is thereby possible to effectively listen to the audio information from the cartilage conduction vibration source, and possible to achieve softer contact with the ear. 
     According to a specific feature, the conductor is sized so as to contact the ear cartilage at a plurality of points. Effective cartilage conduction can thereby be obtained. 
     According to another specific feature, the conductor is sized so as to contact the ear cartilage and block the external auditory meatus. It is thereby possible to effectively listen to audio information from the cartilage conduction vibration source, and effectively reduce exterior noise. 
     According to another specific feature, the conductor has at least a surface area approximating that of the ear lobe. It is thereby possible to effectively listen to audio information from the cartilage conduction vibration source, and block the external auditory meatus in a natural manner according to need. 
     According to another specific feature, the conductor has an acoustic impedance approximating the acoustic impedance of ear cartilage. Audio information from the cartilage conduction vibration source can accordingly be effectively guided to the ear cartilage. 
     According to another specific feature, the conductor is configured as a cover for the mobile telephone. According to such a configuration, housing the mobile telephone in the cover makes it possible to effectively listen to audio information from the cartilage conduction vibration source in a natural manner. 
     According to a more specific feature, the mobile telephone includes an outgoing-talk unit (microphone), and the cover of the mobile telephone includes Larsen effect prevention means between the conduction vibration source and the outgoing-talk unit. It is thereby possible to prevent the Larsen effect while also possible to effectively listen to the audio information from the cartilage conduction vibration source. According to another more specific feature, the mobile telephone includes an outgoing-talk unit, and the cover of the mobile telephone includes an air conduction unit in the vicinity of the outgoing-talk unit. It is thereby possible to listen to the voice of the other party, which is generated by the bone conduction vibration source, while also sending one&#39;s own voice from the outgoing-talk unit, and also thereby possible to have a two-way conversation in a natural manner, even while the mobile telephone remains housed in the cover. 
     According to another specific feature, the conductor is configured as a grip unit of the mobile telephone. It is thereby possible to introduce, to the mobile telephone, an elastic body for effectively guiding the audio information of the conductor, in a manner that is in harmony with the other functions of the mobile telephone. 
     According to another feature, there is provided a mobile telephone comprising: a cartilage conduction vibration source serving as an incoming-talk unit; a conduction vibration source serving as an incoming-talk unit; and a shared outgoing-talk unit. It is thereby possible to provide a mobile telephone permitting a two-way conversation in accordance with the environment of the telephone call. Specifically, providing the shared outgoing-talk unit to an end part of the mobile telephone is useful for the aforesaid configuration. 
     According to another feature, there is provided a mobile telephone comprising: a cartilage conduction vibration source; and a conductor for guiding vibration of the cartilage conduction vibration source to the ear cartilage; wherein the conductor is sized so as to contact the ear cartilage at a plurality of points; is sized so as to contact the ear cartilage and block the external auditory meatus; has at least a surface area approximating that of an ear lobe; or has an acoustic impedance approximating the acoustic impedance of the ear cartilage. Any of these features or a combination thereof makes it possible to listen effectively to sound information using the cartilage conduction vibration source. 
     &lt;Fourth Technical Feature&gt; 
     A fourth technical feature disclosed in the present specification provides a mobile telephone comprising: a cartilage conduction vibration source; a mobile telephone body; an anti-impact cushioning part provided between the mobile telephone body and the cartilage conduction vibration source; and a conductor for guiding the vibration of the cartilage conduction vibration source to the ear cartilage. A vibration source resistant to impact can thereby be employed in a mobile telephone as the cartilage conduction vibration source. According to a specific feature, the conductor is an elastic body. It is thereby possible to cushion impact on the mobile telephone body and additionally impact from outside the conductor, and also thereby possible to obtain effective cartilage conduction. According to another specific feature, a vibration source resistant to impact and suitable as a cartilage conduction vibration source includes a piezoelectric bimorph element. 
     According to another specific feature, the anti-impact cushioning part and the conductor are configured so as to enclose the cartilage conduction vibration source. It is thereby possible to effectively cushion the cartilage conduction vibration source while also rendering the cartilage conduction more effective, rather than compromising the efficacy of cartilage conduction. According to yet another specific feature, the conductor and the anti-impact cushioning part are composed of the same material. According to a further specific feature, the cartilage conduction vibration source is inserted into and integrally molded with the conductor and anti-impact cushioning part. It is thereby made possible to provide a practical configuration by which cushioning efficacy and favorable cartilage conduction efficacy can be simultaneously achieved. According to another specific feature, the conductor and anti-impact cushioning part are joined sandwiching the cartilage conduction vibration source. It is thereby made possible to provide another practical configuration by which cushioning efficacy and favorable cartilage conduction efficacy can be simultaneously achieved. 
     According to yet another feature, the conductor is sized so as to contact the ear cartilage at a plurality of points. According to another specific feature, the conductor is sized so as to contact the ear cartilage and block the external auditory meatus. According to yet another specific feature, the conductor has at least a surface area approximating that of the ear lobe. According to another specific feature, the conductor has an acoustic impedance approximating the acoustic impedance of the ear cartilage. These features make it possible to render cartilage conduction more effective and to reduce exterior noise in accordance with need, while simultaneously cushioning the cartilage conduction vibration source. 
     According to another feature, there is provided a mobile telephone comprising: a cartilage conduction vibration source; a conductor for guiding the vibration of the cartilage conduction vibration source to the ear cartilage; and a resonator for converting the vibration of the cartilage conduction vibration source to air conduction. It is thereby made possible to create a dual use for the cartilage conduction vibration source and to simultaneously obtain both favorable cartilage conduction from the conductor and air conduction from the resonator; it is also thereby possible to effectively listen to sound information. 
     According to a specific feature, the conductor is a rigid body. Cartilage conduction conducts differently depending on the amount of force pushing on the cartilage, and a state of effective conduction can be obtained by increasing the amount of force that is pushing, but this means that when it is difficult to hear the incoming sound, a natural behavior such as increasing the force pushing the mobile telephone against the ear can be utilized to adjust the volume. Such a function also makes it possible to more effectively adjust the volume through adjusting the force that is pushing, due to the conductor being constituted of a rigid body. 
     According to another specific feature, the resonator is an elastic body. The resonator thereby creates cartilage conduction through contact with the tragus or other part of the ear cartilage, and sound from the outer surface of the resonator, which resonates according to the vibration of the cartilage conduction vibration source, is conducted to the tympanic membrane from the external auditory meatus as sound waves. It is thereby possible to effectively listen to sound. 
     According to another specific feature, the resonator is sized so as to contact the ear cartilage at a plurality of points. According to another specific feature, the resonator is sized so as to contact the ear cartilage and block the external auditory meatus. According to yet another specific feature, the resonator has an acoustic impedance approximating the acoustic impedance of the ear cartilage. These features make it possible to render cartilage conduction more effective and to reduce exterior noise in accordance with need. 
     According to another specific feature, the resonator constitutes the incoming-talk unit of the mobile telephone by air conduction. It is thereby made possible to create a dual use for the cartilage conduction vibration source and constitute a typical incoming-talk unit, and also possible to listen to sound in a natural posture, on the basis of the vibration of the cartilage conduction vibration source, without the incoming-talk unit being provided separately. 
     According to another feature, there is provided a mobile telephone comprising: a cartilage conductor for conducting vibration for cartilage conduction to ear cartilage; a resonator for generating sound waves to be conducted to the tympanic membrane through the external auditory meatus by air conduction; and a shared vibration source having a dual purpose as a vibration source for the cartilage conductor and the resonator. It is thereby made possible to create a dual use for the shared vibration source and constitute a cartilage conduction output unit and a typical incoming-talk unit, and also possible to listen to sound in a natural posture, on the basis of the vibration of the shared vibration source, without the incoming-talk unit being provided separately. 
     According to a specific feature, a suitable example of the vibration source includes a piezoelectric bimorph element. It is thereby possible to provide a vibration source suitable for generating favorable cartilage conduction and suitable for a typical incoming-talk unit for generating sound to be conducted to the tympanic membrane from the external auditory meatus. 
     &lt;Fifth Technical Feature&gt; 
     A fifth technical feature disclosed in the present invention provides a mobile telephone comprising: a display surface; a side surface relative to the display surface; and a cartilage conduction vibration unit provided to the side surface and capable of coming into contact of the ear cartilage. The display surface can thereby be prevented from making contact with the ear, cheek, or other body part and from becoming fouled when the cartilage conduction vibration unit is brought into contact with the ear cartilage. 
     According to a specific feature, cartilage conduction vibration units are provided to each of both side surfaces of the display surface. The cartilage conduction vibration unit can thereby be brought into contact with the right ear or the left ear from the state where the display screen is being viewed, without the need to switch the hand holding the mobile telephone. According to a further specific feature, there is provided an incoming-talk unit which is used consistently in any case where either of the cartilage conduction vibration units is being used. 
     According to another specific feature, the incoming-talk unit is provided nearer to the side surface to which the cartilage conduction vibration unit is provided. In such a case, merely providing the cartilage conduction vibration unit to the side surface on a single side allows for the cartilage conduction vibration unit to be brought into contact with the right ear or the left ear by the mobile telephone being turned over. According to a further specific feature, the cartilage conduction vibration unit and the incoming-talk unit form an incoming/outgoing talk unit, which can be inserted into and removed from the mobile telephone. The ability to insert or remove such an incoming/outgoing talk unit allows for flexible usage. According to a further specific feature, the incoming/outgoing-talk unit is configured so as to be capable of short-range wireless communication or so as to be capable of wired communication with the mobile telephone. 
     According to another specific feature, an auxiliary holding unit is provided to the side surface of the side opposite the side surface to which the cartilage conduction vibration unit is provided. The mobile telephone can thereby be more readily held when the cartilage conduction vibration unit is brought into contact with the ear cartilage, and the display surface can thereby be prevented from becoming fouled by fingerprints or the like due to being held during a telephone call. According to a more specific feature, the auxiliary holding unit is configured so as to be extensible from the side surface, in order to prevent the compactness of the mobile telephone from being compromised when the auxiliary holding unit is not needed. 
     According to another feature, there is provided a mobile telephone comprising: a display surface; a cartilage conduction vibration unit which can be brought into contact with the ear cartilage; a detection unit for detecting when the cartilage conduction vibration unit has been contacted with the ear cartilage; and a display controller for changing the display of the display unit to a privacy protection display on the basis of the detection by the detection unit. 
     The feature above makes it possible to prevent another person from catching a glance of a display relating to the call destination or other form of private information during a telephone call. Such a configuration is suitable for when the state becomes such that the display surface is no longer hidden by the posture of the mobile telephone when the cartilage conduction vibration unit is brought into contact with the ear cartilage. An example of a privacy protection display is a predetermined display not containing any private information or a state where nothing is displayed. According to a more specific feature, the display unit is turned on during the privacy protection display, and the display unit is turned off in order to conserve power whenever the detection by the detection unit continues for a predetermined period of time or longer. 
     According to another feature, there is provided a mobile telephone system which includes: a mobile telephone body; and an incoming/outgoing-talk unit, which can be inserted into or removed from the mobile telephone body, and which includes an incoming-talk unit and a cartilage conduction vibration unit that can be brought into contact with the ear cartilage. 
     The feature above makes it possible to enable cartilage conduction in the state where the incoming/outgoing-talk unit is incorporated into the mobile telephone body as well as cartilage conduction in the state where the incoming/outing-talk unit is separated therefrom, and also makes it possible to provide a system permitting flexible usage in accordance with the circumstances. According to a specific feature, the incoming/outgoing-talking unit is configured so as to be capable of short-range wireless communication or so as to be capable of wired communication with the mobile telephone body. 
     According to another feature, there is provided an incoming/outgoing-talk unit for a mobile telephone including a cartilage conduction vibration unit which can be brought into contact with the ear cartilage, an incoming-talk unit, and a unit for communicating with the mobile telephone. Such an incoming/outgoing-talk unit is not only suitable for constituting a mobile telephone system by being combined with a specific mobile telephone, but also assumes a configuration suitable for serving as an incoming/outgoing-talk accessory for a general mobile telephone having a communication unit. According to a specific feature, the incoming/outgoing-talk unit is configured in a pencil shape in which the cartilage conduction vibration unit and the incoming-talking unit are arranged in the vicinity of both ends. According to another specific feature, the communication unit is configured as a short-range wireless communication unit. According to yet another feature, the communication unit is configured so as to include a cable for wired communication with the mobile telephone. 
     According to another specific feature, the communication unit transmits, to the mobile telephone, information relating to the state of contact between the cartilage conduction vibration unit and the ear cartilage. It is thereby made possible for information specific to the usage of the cartilage conduction vibration unit to be transmitted to the mobile telephone, and it is also thereby possible for there to be a favorable link with the mobile telephone. 
     &lt;Sixth Technical Feature&gt; 
     A sixth technical feature disclosed in the present specification provides an incoming/outgoing talk unit for a mobile telephone comprising: an ear-attachment unit; a cartilage conduction vibration unit for making contact with the ear cartilage in the state of attachment by the attachment unit; an outgoing-talk unit; and a short-range wireless communication unit for use with the mobile telephone. This makes it possible to achieve an incoming/outgoing-talk unit suitable for a mobile telephone. An example of suitable ear cartilage in the above is the tragus, by which typically audio information can be transmitted without the ear hole being blocked. 
     According to a specific feature, the incoming/outgoing-talk unit includes a movable unit that is movable relative to the attachment unit, and the cartilage conduction vibration unit is held to the movable unit. According to a further specific feature, the movable unit can be moved in order to alter the state where the cartilage conduction vibration unit is in contact with the cartilage. 
     According to another specific feature, the short-range wireless communication unit transmits, to the mobile telephone, information relating to the position of the movable unit. The mobile telephone is thereby able to transmit appropriate audio information to the incoming/outgoing-talk unit. According to a more specific feature, the short-range wireless communication unit transmits, to the mobile telephone, information relating to the position of the movable unit relative to the attachment unit. 
     According to another feature, the cartilage conduction vibration unit is held via an elastic body. It is thereby possible to cushion an impact against the cartilage conduction vibration unit and also to allow the cartilage conduction vibration unit to move. According to a further specific feature, the cartilage conduction vibration unit is contained and held in the elastic body. This makes it possible to achieve greater cushioning for the cartilage conduction vibration unit. 
     According to a more specific feature, the aforesaid elastic body containing the cartilage conduction vibration unit has an acoustic impedance approximating the acoustic impedance of the ear cartilage. Cushioning for the cartilage conduction vibration unit and suitable cartilage conduction via the elastic body are thereby rendered possible. 
     According to another specific feature, the cartilage conduction vibration source includes a piezoelectric bimorph element. Suitable cartilage conduction vibration is thereby provided. Being held by the aforesaid elastic body is beneficial for the cushioning of such a piezoelectric bimorph element. 
     According to another specific feature, a phase inverter for phase-inverting audio information inputted from the outgoing-talk unit and a controller for outputting, from the cartilage conduction vibration unit, audio information that has been phase-inverted by the phase inverter are positioned in the incoming/outgoing-talk unit. It is thereby possible to provide a highly versatile incoming/outgoing-talk unit making use of the advantages specific to cartilage conduction. According to a further specific feature, an acoustics adjustment unit is provided to the incoming/outgoing-talk unit, and the aforesaid controller outputs, from the cartilage conduction vibration unit, audio information that has been acoustically adjusted by the acoustics adjustment unit and phase-inverted by the phase inverter. More appropriate control is thereby made possible. 
     According to a more specific feature, a contact state detection unit for detecting the state where the cartilage conduction vibration unit is in contact with the ear cartilage is provided to the incoming/outgoing-talk unit, and the controller determines whether or not to output, from the cartilage conduction unit, audio information that has been phase-inverted by the phase inverter, in accordance with the state detected by the contact state detection unit. Appropriate control is thereby made possible. 
     According to another specific feature, the attachment unit is an ear-hooking unit, and the incoming/outgoing-talk unit is configured as a headset. The various features described above are suitable for constituting such a headset. 
     According to another specific feature, the attachment unit is the temple of a pair of eyeglasses, and the incoming/outgoing-talk unit is configured as a pair of eyeglasses. The various features described above are suitable for constituting such a pair of eyeglasses. According to a more specific feature, the cartilage conduction vibration unit can be moved relative to the temple of the eyeglasses. It is thereby possible to withdraw the incoming/outgoing-talk unit whenever a two-way conversation is not being held. 
     &lt;Seventh Technical Feature&gt; 
     A seventh technical feature disclosed in the present specification provides an incoming-talk unit which includes: an ear-attachment unit; and a cartilage conduction vibration unit for conduction cartilage conduction from the outer side of the ear cartilage in the state of attachment by the attachment unit. It is thereby possible to listen to audio information without the external auditory meatus being blocked in both a natural state and a normal state. There are conventionally known eyeglasses-type and other types of bone conduction incoming-talk devices for listening to audio information without the external auditory meatus being blocked, but in the case of using bone conduction, the bone at the front or the rear of the ear must be tightly tucked in by the portion of the inner side or other part of the temple of the eyeglasses, which results in pain and renders long-term usage unbearable. An incoming-talk unit provided with the feature above will not have such a problem, it being possible to listen comfortably to audio information while experiencing a sensation similar to that of ordinary eyeglasses. According to a specific feature, the ear cartilage to which the cartilage conduction is to be conducted is the base of the ear. The outer side of the cartilage of the base of the ear, being close to the inner entrance of the external auditory meatus, is suitable for transmitting sound to the tympanic membrane by generating air conduction to the interior of the external auditory meatus from the cartilage around the entrance to the external auditory meatus, and for direct conduction to the inner ear through the cartilage 
     According to another specific feature, the attachment unit is the temple of eyeglasses. In such a case, the vibration of the cartilage conduction vibration unit can be conducted from the outer side of the ear cartilage through the natural operation of hooking on the eyeglasses. Accordingly, there is no need to clamp down on the bones of the face with the temples of the eyeglasses, as is done in the case of bone conduction. According to a more specific feature, the cartilage conduction vibration unit can be inserted into or removed from the temple of the eyeglasses. It is thereby made possible to conduct cartilage conduction from the outer side of the ear cartilage merely by having the cartilage conduction vibration unit worn on the temple of ordinary eyeglasses, even though the eyeglasses may not be specially designed so as to be provided with the cartilage conduction vibration unit. 
     According to a further specific feature, the incoming-talk unit includes a pair of fitting parts which can each be fitted to the pair of temples of the eyeglasses, and cartilage conduction vibration units are fitted to the temples of the eyeglasses by the fitting parts being fitted. According to a more specific feature, the pair of fitting parts are connected by a glass cord, thus obtaining the practical advantages of a harmonious design and loss prevention. According to a more specific feature, the fitting parts are elastic bodies, thus achieving a degree of freedom in the fitting. 
     According to a further specific feature, one of the aforesaid pair of fitting parts is a dummy. Given that the cartilage conduction vibration unit is fitted only to one ear, a fitting part need only be fitted to one temple, but that alone will be enough to change the thickness of the temple, giving rise to the concern that the eyeglasses will tilt. Therefore, the dummy fitting part is fitted to the other temple, whereby it is possible to maintain the balance of the eyeglasses when the cartilage conduction vibration units are fitted. 
     According to another specific feature, the cartilage conduction vibration unit is arranged on one of the pair of fitting parts, and a power source is arranged at the other. It is thereby possible to arrange the cartilage conduction vibration unit and the related constituent elements in a limited space while the left and right temples are also balanced. It is further possible to connect the pair of fitting parts with a glass cord having a dual purpose for creating an electric connection between the two, whereby a plurality of constituent elements can be divided to the left and right temples while a harmonious design and also a mutual electric connection can be maintained. 
     According to another further specific feature, cartilage conduction vibration units are arranged at both of the pair of fitting parts. It is thereby possible to listen to audio information stereophonically while achieving a balance between the left and right temples. According to another feature, the cartilage conduction vibration units can also be arranged directly on both of the pair of temples of the eyeglasses. 
     According to another specific feature, the incoming-talk unit is provided with: a detection unit for detecting when the ear cartilage are deformed due to the ear being covered; an outgoing-talk unit; a phase inverter for phase-inverting audio information inputted from the outgoing-talk unit; and a controller for outputting, from the cartilage conduction vibration unit, the audio information that has been phase-inverted by the phase inverter in accordance with the detection by the detection unit. It is thereby possible to attenuate the discomfort of one&#39;s own voice when the ear is covered in order to listen to louder audio information and the earplug bone conduction effect is produced, while also obstructing exterior noise. 
     According to another specific feature, the attachment unit is an ear-hooking unit. In such a case, even a person who does not require eyeglasses can listen to audio information in a natural state and a normal state without the external auditory meatus being blocked. 
     According to another feature, there is provided an incoming-talk unit for 3D viewing, comprising: a 3D viewing adjustment unit; a temple including a unit for adjusting contact with the temple of eyeglasses for adjusting vision when fitted over eyeglasses for adjusting vision; and an audio information output unit provided to the temple. It is thereby possible to appropriately listen to audio information both in a case where the incoming-talk unit for 3D viewing is fitted directly without eyeglasses, and also in a case where the same is fitted over eyeglasses for adjusting vision. 
     According to a specific feature, the audio information output unit is a cartilage conduction vibration unit. According to a further specific feature, the cartilage conduction vibration unit conducts cartilage conduction from the outer side of the ear cartilage. The aforesaid contact adjustment unit allows for the vibration of the cartilage conduction vibration unit to be effectively transmitted from the outer side of the ear cartilage in particular when the incoming-talk unit for 3D viewing is fitted over the eyeglasses for adjusting vision. 
     &lt;Eighth Technical Feature&gt; 
     An eighth technical feature disclosed in the present specification provides a mobile telephone comprising: a cartilage conduction vibration source for guiding an audio signal to the ear cartilage; and a low-frequency source for guiding, to the cartilage conduction vibration source, a low-frequency vibration signal of a lower signal than the audio signal. The vibration source can thereby be given a dual purpose for cartilage conduction and low-frequency vibration, and the cost of the vibration source and thereby be reduced. 
     According to a specific feature, a mobile telephone is provided with a touch detection unit for detecting touch by a finger, wherein the low-frequency source introduces, to the cartilage delivery vibration source, the low-frequency vibration signal in response to a detection of touch by the touch detection unit, and transmits the low-frequency vibration of the cartilage delivery vibration source to the finger touching. A suitable example of such a touch detection unit is a touch panel provided to a display screen. 
     According to another specific feature, the cartilage conduction vibration source serves a dual purpose as the touch detection unit. The cartilage conduction vibration source can thereby serve to guide audio signals to the ear cartilage, to output low frequencies, and to detect touch, and the cost of the vibration source can also thereby be reduced. This feature is suitable for a case where a contact-free motion sensor for detecting movement in the vicinity of the display screen is provided. 
     According to another specific feature, a delay lasting a predetermined period of time after the detection by the touch detection unit is allowed to pass, and the low-frequency vibration signal is introduced to the cartilage conduction vibration source. Feedback for a touch result can thereby be provided to the finger touching, without confusion. 
     According to another specific feature, a vibration insulation material for preventing the transmission of audio signals is interposed between the cartilage conduction vibration source and an outer wall part for outwardly conduction the vibration of the cartilage conduction vibration source, which is made to vibrate by the introduction of a low-frequency vibration signal having a low frequency. The leakage of audio signals to the outer wall part and elsewhere, the generation of unneeded air conduction, and other defects can thereby be prevented. 
     According to a further specific feature, the vibration insulation material prevents the transmission of vibration having a frequency at or above a predetermined frequency, and permits the transmission of vibration at or below the predetermined frequency. An audio signal thereby enables a low-frequency vibration to be relayed to the outer wall part from the cartilage conduction vibration source even while there is obstruction. According to another further specific feature, a low-frequency signal of the low-frequency source is configured so as to include the resonance frequency of the vibration insulation material. An audio signal can thereby cause the vibration insulation material to resonate for a low-frequency vibration even while there is obstruction, whereby the low-frequency vibration can be transmitted to the outer wall part from the cartilage conduction vibration source. 
     According to another specific feature, a switching unit for switching between introducing an audio signal and introducing a low-frequency signal of a low frequency is provided to the cartilage conduction vibration source. The cartilage conduction vibration source can thereby be appropriately applied to a plurality of objectives. 
     According to another specific feature, there is provided an audio signal output device for a mobile telephone characterized by comprising: eyeglass lenses; eyeglass temples; cartilage conduction vibration units for conducting cartilage conduction from the outer side of the ear cartilage, which are arranged at the eyeglass temples; a sound signal source unit for transmitting output to the cartilage conduction vibration units; and a unit for communicating with the mobile telephone. Diverse links with the mobile telephone are thereby made possible. According to a further specific feature, incoming-talk units are provided to the eyeglass temples; as an example of a more specific feature, the incoming-talk units are configured as bone conduction microphones. Such configurations are appropriately used for eyeglass temples naturally brought up against the face when the eyeglasses are worn, and permit two-way conversation. 
     According to another feature, there is provided a sound signal output device which includes: eyeglass lenses; eyeglass temples; cartilage conduction vibration units for conducting cartilage conduction from the outer side of the ear cartilage, which are arranged at the eyeglass temples; and a sound signal source unit for transmitting output to the cartilage conduction vibration units. A person wearing the eyeglasses can thereby enjoyably receive sound signals of the sound signal source unit in a natural state. According to a specific feature thereof, the eyeglass temples are a pair, and the cartilage conduction vibration units are arranged at each of both of the pair of eyeglass temples, and the output of the sound signal source unit is transmitted to each of the cartilage conduction vibration units. A pair of temples originally provided to eyeglasses can thereby be utilized and stereo sound signals can be enjoyably received without the ear being blocked. 
     According to another feature, there is provided a sound signal output device for a mobile telephone characterized by comprising: eyeglass lenses; eyeglass temples; cartilage conduction vibration units for conducting cartilage conduction from the outer side of the ear cartilage, which are arranged at the eyeglass temples; bone conduction microphones arranged at the eyeglass temples; and a unit for communicating with the mobile telephone. It is thereby possible to provide an incoming/outgoing-talk unit suitable for a mobile telephone for a person who wears eyeglasses. 
     &lt;Ninth Technical Feature&gt; 
     A ninth technical feature disclosed in the present specification provides a mobile telephone characterized by comprising: a cartilage conduction vibration source having a primary vibration direction, the cartilage conduction vibration source being adapted to guide an audio signal to the ear cartilage; a holding structure for avoiding the primary vibration direction and for holding the cartilage conduction vibration source; and an audio signal input unit for inputting an audio signal to the cartilage conduction vibration source. An audio signal can thereby be effectively guided to the ear cartilage, and useless vibration of the cartilage conduction vibration source can be prevented from being conducted to the mobile telephone. 
     According to a specific feature, the mobile telephone is provided with a vibration output structure for guiding, to the outer surface of the mobile telephone, vibration in the primary vibration direction of the cartilage conduction vibration source. An audio signal can thereby be effectively guided to the ear cartilage from the cartilage conduction vibration. More specifically, the vibration output structure is an opening part provided to the mobile telephone. 
     According to a further specific feature, there is a vibration conduction unit connected to the surface of the primary conduction vibration direction of the cartilage conduction vibration source and exposed from the opening part. An audio signal can thereby be effectively guided to the ear cartilage from the cartilage conduction vibration without the design of the outer surface of the mobile telephone being compromised. 
     According to another specific feature, an elastic body is provided between the vibration conduction unit and the opening part. Useless vibration of the cartilage conduction vibration source can thereby be prevented from being conducted to the mobile telephone without the design of the outer surface of the mobile telephone being compromised. 
     According to another specific feature, an output structure is provided to the upper corner parts of the mobile telephone. An audio signal can thereby be effectively guided from the cartilage conduction vibration to the tragus or other part of the ear cartilage due to the natural manner in which the mobile telephone is held. 
     According to another specific feature, the output structure is provided to the side surface parts of the mobile telephone. An audio signal can thereby be effectively guided from the cartilage conduction vibration to the tragus or other part of the ear cartilage even while contact with the cheek or the like can be prevented from fouling the display surface or other element of the mobile telephone. 
     According to a specific feature, the cartilage conduction vibration source is a piezoelectric bimorph element, where a hold in accordance with the structure and vibration properties of the piezoelectric bimorph element makes it possible to effectively guide an audio signal to the ear cartilage and to prevent useless vibration of the cartilage conduction vibration source from being conducted to the mobile telephone. 
     According to a more specific feature, the primary vibration direction is avoided and the middle part of the cartilage conduction vibration source is held. It is thereby possible to effectively guide an audio signal to the ear cartilage, and also to prevent useless vibration of the cartilage conduction vibration source from being conducted to the mobile telephone. 
     According to another feature, there is provided a mobile telephone characterized by comprising: a cartilage conduction vibration source having a primary vibration surface and an outer surface substantially orthogonal thereto, the cartilage conduction vibration source being adapted to guide an audio signal to the ear cartilage; a holding structure for holding the cartilage conduction vibration source at a ridge between the primary vibration surface and the outer surface; and an audio signal input unit for inputting an audio signal to the cartilage conduction vibration source. An audio signal can thereby be effectively guided to the ear cartilage, and also useless vibration of the cartilage conduction vibration source can be prevented from being conducted to the mobile telephone. 
     According to another feature, there is provided a mobile telephone characterized by comprising: a cartilage conduction vibration source for guiding an audio signal to the ear cartilage; a holding structure having a concave and convex surface for holding the cartilage conduction vibration source; and an audio signal input unit for inputting an audio signal to the cartilage conduction vibration source. An audio signal can thereby be effectively guided to the ear cartilage, and also useless vibration of the cartilage conduction vibration source can be prevented from being conducted to the mobile telephone. 
     &lt;Tenth Technical Feature&gt; 
     A tenth technical feature disclosed in the present specification provides a vibration element characterized in that an electrode is provided to the middle part of the longitudinal direction. The vibration element can thereby be electrically connected at the middle part of the longitudinal direction, and both ends of the vibration element can thereby be released from the burden of an electrical connection. According to a specific feature, the vibration element includes: a metal sheet; piezoelectric ceramic sheets provided to both sides of the metal sheet; and a resin for covering the periphery thereof, wherein the electrode includes a first electrode pulled out to the surface of the resin from the middle part of the longitudinal direction of the metal sheet, and a second electrode pulled out to the surface of the resin in the vicinity of the first electrode from each of the piezoelectric ceramic sheets. 
     According to another specific feature, the electrodes are pulled out on the surface of the vibration direction of the vibration element. According to another specific feature, the electrodes are pulled from the surface of the resin in the direction substantially orthogonal to the metal sheet and the piezoelectric ceramic sheets. According to yet another specific feature, the resin of the vibration element includes a primary vibration direction surface substantially parallel to the metal sheet and the piezoelectric ceramic sheets and also a non-vibration direction surface substantially orthogonal thereto, and the electrodes are pulled out from such a primarily vibration direction surface of the resin. According to another specific feature, the electrodes are pulled out to the surface of the resin upon being curved substantially 90° within the resin. These features are suitable for support the vibration element from the non-vibration direction. 
     According to another specific feature, there is provided a mobile telephone in which the above-described vibration element is supported on the middle part of the longitudinal direction. This makes it possible to achieve a mobile telephone capable of transmitting the vibration from both ends of the vibration element to the ear cartilage and the like by, for example, cartilage conduction. According to a more specific feature, the vibration element is sandwiched and supported at the middle part of the longitudinal direction from the direction substantially parallel to the metal sheet and piezoelectric ceramic sheets of the piezoelectric bimorph elements. It is thereby made possible to hold the vibration element in the state where less vibration is conducted to the mobile telephone. 
     According to a more specific feature of the mobile telephone described above, vibration conductors are provided to both ends of the vibration element. According to a further specific feature, the vibration conductors are provided to the vicinity of the corners of the mobile telephone. Vibration can thereby be readily conducted to the ear cartilage. 
     According to another specific feature of the mobile telephone described above, the vibration conductors are provided to the side surfaces of the mobile telephone. The front surface of the mobile telephone, to which a display surface or the like is provided, can thereby be prevented from becoming fouled due to contact with the cheek. According to a more specific feature, the vibration conductors assume a long shape along the side surfaces of the mobile telephone. It is thereby possible to obviate the need to strictly select the position to be held against the ear and to permit contact at many points. 
     According to another feature, there is provided a mobile telephone that is guarded at the corners of the outer wall of the body, the mobile telephone including vibration units provided in the vicinity of the corners. The corners of the outer wall of the mobile telephone are suitable for obtaining cartilage conduction by being held up against the ear cartilage, but are conversely also always susceptible to collision with an external unit. According to the configuration described above, cartilage conduction to, for example, the tragus or other part of the ear cartilage is made readily possible while there is also a guard against collision from an external unit. 
     According to another feature, there is provided a mobile telephone including a pair of vibration conductors having a long shape along the side surfaces of the mobile telephone, each of the vibration conductors being provided so as to be substantially orthogonal to both ends of the longitudinal direction of the vibration element. It is thereby possible to make use of the vibration of both ends of the vibration element and to use the long regions of the two side surfaces of the mobile telephone as vibration sources for cartilage conduction. 
     According to yet another feature, there is provided a mobile telephone having a pair of vibration elements having a long shape, each of which elements provided along the two side surfaces of the mobile telephone. It is thereby possible to use the long regions of the two side surfaces of the mobile telephone as vibration sources for cartilage conduction while also independently controlling the respective vibrations of both sides. 
     According to yet another feature, there is provided a mobile telephone including: a vibration element having a long shape provided along one side surface of the mobile telephone, and a holding unit provided to the side surface of the side opposite the side surface to which the vibration element is provided. It is thereby possible to clearly understand which side is the cartilage conduction vibration source. 
     There is provided a mobile telephone including: a vibration element provided to the vicinity of a top side of the mobile telephone; and an elastic vibration conductor for covering the vibration element and forming the top side of the mobile telephone. Cartilage conduction can thereby be obtained from contact with the ear irrespective of being the front surface, rear surface, or side surface in the vicinity of the top side of the mobile telephone. 
     &lt;Eleventh Technical Feature&gt; 
     An eleventh technical feature disclosed in the present specification provides a mobile telephone comprising a cartilage conduction vibration unit supported inside a chassis structure and is adapted to conduct cartilage conduction vibration to the surface of the chassis structure. It is thereby possible to hold up any place of the surface of the mobile telephone against the ear cartilage and listen to sound by cartilage conduction. There is also greater freedom in the manner in which the cartilage conduction vibration unit is held, and the holding structure is also simplified. 
     According to a specific feature, the surface of the chassis structure has a surface to made to vibrate, and the cartilage conduction vibration unit is held within the chassis structure such that the primary vibration direction thereof is in the direction substantially orthogonal to the surface made to vibrate. Vibration can thereby be effectively conducted to the surface made to vibrate intended for cartilage conduction. According to a more specific feature, the cartilage conduction vibration unit has a piezoelectric bimorph element including a metal sheet, the metal sheet being held in the direction substantially parallel to the surface made to vibrate. The main vibration direction of the cartilage conduction vibration unit can thereby be made to be the direction substantially orthogonal to the surface to be vibrated. 
     According to a further specific feature, the mobile telephone includes a display surface, and the cartilage conduction vibration unit is held such that the primary vibration direction thereof is substantially orthogonal to the display surface. The display surface on the mobile telephone or the rear surface thereof can thereby be made to vibrate effectively, and it is thereby possible to bring the mobile telephone up against the ear cartilage over a broad range. According to a further specific feature, the display surface has a touch panel operation surface, and the cartilage conduction vibration unit has a dual purpose as a vibration source for feedback for the sensation of touch panel operation. 
     According to another specific feature, the cartilage conduction vibration unit is held such that the primary vibration direction thereof is in the direction substantially orthogonal to a side surface of the mobile telephone. The side surface of the mobile telephone can thereby be made to vibrate effectively, and effective cartilage conduction can thereby be obtained even while the display surface is prevented from coming into contact with the cheek and becoming fouled. 
     According to another feature, there is included an impact detection surface, wherein the cartilage conduction vibration unit is held within the chassis structure such that the primary vibration direction thereof is in the direction substantially orthogonal to the impact detection surface. The cartilage conduction vibration unit can thereby be given the dual purpose of effectively detecting impact. 
     According to another feature, the cartilage conduction vibration unit has a dual purpose as a vibration source for providing notification of an incoming call. In such a case, because the vibration of the cartilage conduction vibration unit is conducted to all locations on the surface of the mobile telephone, effective notification of an incoming call can be provided. 
     According to another feature, the cartilage conduction vibration unit is held rigidly within the chassis structure. According to a further specific feature, the cartilage conduction vibration unit is held directly to the chassis structure. These features simplify the holding structure of the cartilage conduction vibration unit and are suitable for effectively transmitting vibration. 
     According to another feature, the mobile telephone includes a horizontal stationary state detection unit, the vibration of the cartilage conduction vibration unit being stopped whenever a horizontal stationary state has been detected. It is thereby possible to prevent the occurrence of uncomfortable vibration noise at times such as when the mobile telephone is placed on a desk during a telephone call. 
     According to further specific feature, the mobile telephone includes a touch panel operation surface, wherein the cartilage conduction vibration unit has a dual purpose as a vibration source for feedback for the sensation of a touch panel operation, and the vibration for feedback for the sensation of a touch panel operation in the cartilage conduction vibration unit is not stopped even when the horizontal stationary state is detected. According to another specific feature, the cartilage conduction vibration unit serves a dual purpose for an impact detection function, and the impact detection function in the cartilage conduction vibration unit is not stopped even when the horizontal stationary state is detected. These features are suitable for smooth GUI operation. 
     According to another further specific feature, the cartilage conduction vibration unit serves a dual purpose as a vibration source for providing notification of an incoming call, and the vibration for providing notification of an incoming call in the cartilage conduction vibration unit is not stopped even when the horizontal stationary state is detected. This feature is suitable for accurately providing notification of an incoming call. 
     &lt;Twelfth Technical Feature&gt; 
     A twelfth technical feature disclosed in the present specification provides a mobile telephone comprising: a chassis structure having a display surface; and a cartilage conduction vibration unit supported in the chassis structure so as to have a primary vibration surface inclined relative to the display surface. Vibration for cartilage conduction can thereby be conducted to the chassis structure from the direction of incline relative to the display surface. 
     According to a specific feature, the chassis structure includes an inclined surface parallel to the primary vibration surface. The inclined surface can thereby be brought into contact with the ear cartilage to obtain effective cartilage conduction even while fouling due to the display surface coming into contact with the cheek can be prevented, and a vibration component from the display surface or back surface of the mobile telephone can thereby also be obtained. According to a more specific feature, the chassis structure has a side surface orthogonal to the display surface, wherein an inclined plane is provided between the side surface and the surface parallel to the display surface. The inclined surface can thereby be provided with a design in which a box-type mobile telephone is beveled. 
     According to another specific feature, the chassis structure has a cylindrical surface containing the cartilage conduction vibration unit. It is thereby possible to obtain cartilage conduction by bringing the ear cartilage up against the cylindrical surface and a desired position on the display surface or back surface, and also possible thereby to bring the cylindrical surface into contact with the ear cartilage to effectively obtain cartilage conduction in the state where the display surface is not in contact with the face. 
     According to yet another specific feature, the chassis structure includes a side surface orthogonal to the display surface, and the vibration of the primary vibration surface in the cartilage conduction vibration unit is transmitted to a side surface and to the surface parallel to the display surface. It is thereby possible to obtain cartilage conduction in any case where either the side surface or the surface parallel to the display surface is brought into contact with the ear cartilage. 
     According to another specific feature, the chassis structure has an upper surface orthogonal to the display surface, and the vibration of the primary vibration surface in the cartilage conduction vibration unit is transmitted to the surface parallel to the display surface and to the upper surface. It is thereby possible to obtain cartilage conduction in any case where either the upper surface or the surface parallel to the display surface is brought into contact with the ear cartilage. In such a case, the vibration of the upper surface is suitable for contact in the state where the mobile telephone is pushed up against the ear cartilage while bringing the display surface into contact with the face is being avoided, and also for obtaining the earplug bone conduction effect by pushing stronger to block the external auditory meatus with the tragus. An example of the incline of the primary vibration surface in the cartilage conduction vibration unit is the range of about 30° to 60° relative to the display surface. 
     According to another specific feature, the vibration of both sides of a pair of opposing primary vibration surfaces in the cartilage conduction vibration unit is transmitted to the chassis structure. The vibration of the pair of primary vibration surfaces of the cartilage conduction vibration unit is thereby effectively utilized. According to further specific feature, the chassis structure has a side surface or upper surface orthogonal to the display surface, and the vibration of both sides of the primary vibration surfaces in the cartilage conduction vibration unit is respectively transmitted to the side surface or upper surface and to the surface parallel to the display surface. The vibration of the pair of primary vibration surfaces of the cartilage conduction vibration unit is thereby utilized as vibration sources having opposite directions. The positions to which the vibration of the pair of primary vibration surfaces is transmitted may be mutually opposing portions of the primary vibration surfaces, but the configuration may also be such that the vibration is respectively transmitted to the side surface or upper surface and to the surface parallel to the display surface from mutually crossing positions. 
     According to another feature, there is provided a mobile telephone comprising: a chassis structure, and a cartilage conduction vibration unit in which vibration is unrestrictedly permitted in a part of the primary vibration surface and in which another part of the primary vibration surface is supported within the chassis structure. It is thereby possible for the vibration of the cartilage conduction vibration unit to be effectively transmitted to the chassis structure while a loss in the freedom of vibration thereof is avoided. 
     According to a specific feature, the primary vibration surface at the middle part of the cartilage conduction vibration unit is supported in the chassis structure, and vibration is unrestrictedly permitted in the primary vibration surface at both end parts of the cartilage conduction vibration unit. The middle part at which support occurs may be the middle part of the cartilage conduction vibration unit, but when the behavior during the implementation of the cartilage conduction vibration unit lacks left-right symmetry, in order to compensate therefor, the configuration may also be such that the primary vibration surface is supported in the chassis structure at an off-center middle part. 
     According to another specific feature, a plurality of portions of the primary vibration surface of the cartilage conduction vibration unit is supported in the chassis structure. According to a more specific feature, the configuration is such that the primary vibration surfaces at both end parts of the cartilage conduction vibration unit are each supported in the chassis structure, and vibration is unrestrictedly permitted at the primary vibration surface in the middle part of the cartilage conduction vibration unit. 
     According to yet another feature, there is provided a mobile telephone comprising: a chassis structure; and a cartilage conduction vibration unit supported within the chassis structure by the interposition of a vibration conduction elastic body between the primary vibration surfaces. It is thereby possible for the vibration of the cartilage conduction vibration unit to be effectively transmitted to the chassis structure while a loss in the freedom of vibration thereof is avoided. 
     &lt;Thirteenth Technical Feature&gt; 
     A thirteenth technical feature disclosed in the present specification provides a mobile telephone configured such that a part of the cartilage conduction vibration unit is supported on the inside of the chassis in the vicinity of a corner part of the chassis and another part vibrates unrestrictedly, whereby the vibration of the cartilage conduction vibration unit is transmitted to the corner part of the chassis. The corner part can thereby effectively be made to vibrate while a structure in which the corner part would be susceptible to collision is avoided. 
     According to a specific feature, the cartilage conduction vibration unit is supported on the inside of the upper surface of the chassis at the vicinity of the corner part of the chassis. According to another specific feature, the cartilage conduction vibration unit is supported on the inside of a side surface of the chassis in the vicinity of the corner part of the chassis. According to yet another feature, the cartilage conduction vibration unit is supported on the inside of the front surface of the chassis in the vicinity of the corner part of the chassis. The features above can also be combined as appropriate, in terms of the manner in which the cartilage conduction vibration unit is supported. 
     According to another specific feature, the cartilage conduction vibration unit has an electrical terminal and is supported such that the vicinity of the electrical terminal vibrates unrestrictedly. The cartilage conduction vibration unit can thereby be supported at a position of the chassis closer to the inside of the corner part and the display surface at the corner part can thereby effectively be made to vibrate, without there being any hindrance to the presence of the electrical terminal. 
     According to another specific feature, the cartilage conduction vibration unit is supported such that the primary vibration direction thereof is perpendicular to the upper surface of the chassis. According to yet another feature, the cartilage conduction vibration unit is supported such that the primary vibration direction thereof is perpendicular to a side surface of the chassis. These features make it possible to adopt a configuration such that the vibration is more effective closer to the upper surface or closer to the side surface of the corner part of the chassis. According to yet another specific feature, the cartilage conduction vibration unit is supported such that the primary vibration thereof is perpendicular to the front surface of the chassis. It is thereby possible to adopt a configuration such that the vibration is more effective closer to the front surface of the corner part of the chassis. According to yet another feature, the cartilage conduction vibration unit is supported such that the primary vibration direction thereof is inclined relative to the front surface of the chassis. It is thereby possible allocate vibration components to the front surface and to the surface orthogonal thereto. 
     According to another feature, a circuit for the cartilage conduction vibration unit is supported on the inside of the chassis as a vibration unit integrated with the cartilage conduction vibration unit. It is thereby possible to configure the entirety of the cartilage conduction vibration unit and the circuit related thereto as a vibration unit. 
     According to a more specific feature, the cartilage conduction vibration unit has an electrical terminal, and the circuit for the cartilage conduction vibration unit is arranged in the vicinity of the electrical terminal. It is thereby possible to make effective use of the space in the vicinity of the electrical terminal to configure the vibration unit. According to a more specific feature, the portion of the vibration unit in the vicinity of the electrical terminal is supported. The portion to which the electrical terminal is not provided can thereby be made to unrestrictedly vibrate. 
     According to another feature, there is provided a mobile telephone configured such that the part of the cartilage conduction vibration unit to which the electrical terminal is not provided is supported on the inside of the chassis, and the other part to which the electrical terminal is provided is made to unrestrictedly vibrate, whereby the vibration of the cartilage conduction vibration unit is transmitted to the exterior of the chassis. The cartilage conduction vibration unit can thereby be supported at a position of the chassis closer to the inside of the corner part and the display surface at the corner part can thereby effectively be made to vibrate, without there being any hindrance to the presence of the electrical terminal. 
     According to another feature, there is provided a vibration unit characterized by the integration of a cartilage conduction vibration unit having an electrical unit with a circuit for the cartilage conduction vibration unit arranged in the vicinity of the electrical terminal. It is thereby possible to make effective use of the space in the vicinity of the electrical terminal to configure the vibration unit. 
     According to a specific feature, the circuit has an amplifier for the cartilage conduction vibration unit. The cartilage conduction vibration unit can thereby be effectively supported without the use of the space around the cartilage conduction vibration unit, and the cartilage conduction vibration unit can also thereby be made to vibration efficiently 
     According to a specific feature, the circuit has an adjustment unit to electrically compensate for the variances of the cartilage conduction vibration unit. The cartilage conduction vibration unit can thereby be effectively supported without the use of the space around the cartilage conduction vibration unit, and performance can also thereby be maintained relative to the variances in the cartilage conduction vibration unit. 
     &lt;Fourteenth Technical Feature&gt; 
     A fourteenth technical feature disclosed in the present specification provides a mobile telephone in which a part of the cartilage conduction vibration unit is supported by the inside of an elastic body, and the outside of the elastic body is arranged at a corner part of the chassis. The freedom of the cartilage conduction vibration unit to vibrate can thereby be ensured, and the vibration thereof can thereby be efficiently guided to the corner part of the chassis for cartilage conduction by contact with the ear. 
     According to a specific feature, in the mobile telephone, the other part of the cartilage conduction vibration unit is supported by the inside of a second elastic body, and the outside of the second elastic body is arranged at another corner part of the chassis. The cartilage conduction vibration unit can thereby be more reliably supported while the freedom of the cartilage conduction vibration unit to vibrate can be ensured, and also the respective vibrations from both of the support units can thereby be efficiently guided to the corner parts of the chassis for cartilage conduction by contact with the ear. 
     According to a further specific feature, in the mobile telephone, the cartilage conduction vibration unit is shaped to have two end parts, the two end parts of the cartilage conduction vibration unit each being supported on the insides of the elastic body and second elastic body, and the outsides of the elastic body and the second elastic body are each arranged at opposite corner parts of the chassis. The two end parts of the cartilage conduction vibration unit can thereby be reliably supported and the freedom of both end parts to vibrate can be ensured to a certain degree by the support of the elastic bodies, and also the vibration of both ends can thereby be transmitted for cartilage conduction from either of the opposite corner parts of the chassis. 
     According to another technical feature, the cartilage conduction vibration unit has an electrical terminal, and one of either of the elastic body or the second elastic body includes an electrical terminal and supports the cartilage conduction vibration unit. It is thereby possible to reliably support the electrical terminal, including the connective wiring thereof, and the cartilage conduction vibration unit even while the freedom thereof to vibrate is ensured to a certain degree, and also thereby possible to also transmit vibration for cartilage conduction from the portion at which the electrical terminal is found. 
     According to another specific feature, the cartilage conduction vibration unit is eccentric between a corner part and another corner part. It is thereby possible to provide compensation for the imbalance of the cartilage conduction vibration unit, and also the layout of the various parts inside the mobile telephone can be designed with a greater degree of freedom. 
     According to another specific feature, the elastic body is formed with a material having an acoustic impedance approximating that of the ear cartilage. Effective cartilage conduction can thereby be obtained even while the freedom to vibrate is ensured. 
     According to another specific feature, in the mobile telephone, elastic bodies are also arranged at two other corner parts of the chassis where the cartilage conduction vibration unit is not arranged and are configured together with the elastic body at the corner part of the chassis where the cartilage conduction vibration unit is arranged so as to attenuate collision from the exterior unit to the four corners of the mobile telephone. The elastic bodies can thereby be given a dual purpose also as protectors for attenuating collision to the corner parts. This feature makes use of the elastic bodies at the corner parts for the dual objectives of appropriately making use of the corner parts of the mobile telephone to make contact with the ear for cartilage conduction and also protecting the corner parts of the mobile telephone, which are susceptible to collision. According to another specific feature, when the cartilage conduction vibration unit is supported such that the primary vibration direction thereof is orthogonal to the front surface of the chassis, the mobile telephone can be brought into contact with the ear for cartilage conduction without any change in the level of comfort experienced with a normal telephone call. 
     According to another feature, there is provided a mobile telephone in which a very slight stepped concavity is provided to the surface of the mobile telephone and the cartilage conduction vibration unit is arranged on the base surface of the concavity. It is thereby possible to protect the cartilage conduction vibration unit from a collision to the mobile telephone from an external unit, and also thereby possible to use the elastic deformation thereof to readily bring the cartilage conduction vibration unit into contact with the ear cartilage. According to a specific feature, the arrangement is such that the vibration surface of the cartilage conduction vibration unit is positioned on the base surface of the concavity, thus achieving efficient cartilage conduction. According to a more specific feature, a protective layer is provided to the vibration surface; wherever possible, the ear cartilage is brought into direct contact with the vibration surface, and damage to the vibration surface is prevented. According to another specific feature, the concavity is provided to a side surface of the mobile telephone, whereby the advantages of having the concavity can suitably be enjoyed. 
     According to another feature, there is provided a mobile telephone provided with a plurality of cartilage conduction vibration units having primary vibration surfaces which are not mutually parallel. Effective cartilage conduction is thereby possible in a plurality of directions. According to a specific feature, the primary vibration surface of one of the plurality of cartilage conduction vibration units is substantially parallel to a side surface of the mobile telephone, and the primary vibration surface of another one of the plurality of cartilage conduction vibration units is substantially parallel to the front surface of the mobile telephone. Cartilage conduction from the side surface, which is very advantageous, is thereby possible, as is cartilage conduction from the front surface, which is no less comfortable than when a mobile telephone is normally used. 
     According to another specific feature, an arrangement is employed in which the cartilage conduction vibration units are mutually parallel in the longitudinal direction. According to yet another specific feature, an arrangement is employed in which the cartilage conduction vibration units are not mutually parallel in the longitudinal direction. 
     &lt;Fifteenth Technical Feature&gt; 
     A fifteenth technical feature disclosed in the present specification provides a mobile telephone comprising: a plurality of elastic bodies arranged at each of a plurality of corner parts of the chassis; and cartilage conduction vibration units provided to each of the plurality of elastic bodies. There is thereby provided a mobile telephone in which the corner parts of the mobile telephone can be brought up against the ear cartilage for cartilage conduction and in which the cartilage conduction vibration units arranged at the corner parts can be protected from collision with an external unit. 
     According to a specific feature, the cartilage conduction vibration units are provided to the elastic bodies so as not to be exposed at the outer surfaces of the mobile telephone. According to a more specific feature, each of the cartilage conduction vibration units is embedded in the elastic bodies. According to yet another specific feature, each of the cartilage conduction vibration units is provided to the insides of the elastic bodies. 
     According to another specific feature, the plurality of cartilage conduction vibration units provided to each of the elastic bodies is given respectively different vibration directions. It is thereby possible to obtain favorable cartilage conduction whenever an elastic body is held to the ear cartilage from different directions. According to a more specific feature, the cartilage conduction vibration units can be controlled mutually independently. 
     According to another specific feature, the cartilage conduction vibration units provided to the elastic bodies are electromagnetic vibrators. An electromagnetic vibrator, similarly with respect to a piezoelectric bimorph element, is an example of an element suitable for providing a vibration source in the cartilage conduction vibration units. 
     According to another feature, there is provided a mobile telephone comprising elastic bodies arranged on the chassis and cartilage conduction vibration units provided to the elastic bodies, wherein the elastic bodies and the cartilage conduction vibration units are configured as replaceable unit parts. It is thereby also possible, among other possibilities, to facilitate replacing the elastic bodies and cartilage conduction vibration units, and to provide a product having different cartilage conduction vibration units while other parts are essentially the same. 
     According to another feature, there is provided a mobile telephone comprising: a plurality of cartilage conduction vibration units provided to the chassis and given different vibration directions; and a controller for independently controlling each of the plurality of cartilage conduction vibration units. It is thereby possible to obtain favorable cartilage conduction whenever an elastic body is held to the ear cartilage from different directions. According to a more specific feature, the plurality of provided cartilage conduction vibration units is controlled in accordance with the posture of the mobile telephone, and control in accordance with the direction in which an elastic body is held against the ear becomes possible. 
     According to another feature, there is provided a mobile telephone comprising: elastic bodies arranged on the chassis and including unrestrictedly vibrating parts where vibration is not controlled; and cartilage conduction vibration units provided to the unrestrictedly vibrating parts of the elastic bodies. The vibration of the cartilage conduction vibration units is thereby more favorably transmitted to the elastic bodies. 
     According to a specific feature, the unrestrictedly vibrating parts are elongated parts elongated to the inside of the chassis. It is thereby possible to appropriately hold the cartilage conduction vibration units within the mobile telephone even while vibration can be favorably transmitted. 
     According to a specific feature, the unrestrictedly vibrating parts face a window unit provided to the chassis. The vibration of the cartilage conduction vibration units can thereby be favorably transmitted via the window unit. According to a more specific feature, the unrestrictedly vibrating parts cover the window unit and have a rear surface facing the window unit, the cartilage conduction vibration units being provided to the rear surface. The vibration of the cartilage conduction vibration units provided to the inside of the mobile telephone can thereby be favorably transmitted to the elastic bodies via the window unit. 
     According to another feature, there is provided a mobile telephone comprising: elastic bodies arranged on a chassis; cartilage conduction vibration units provided to the elastic units; and balancers provided to the cartilage conduction vibration units. It is thereby possible to adjust the acoustic properties of the cartilage conduction vibration units transmitted to the elastic bodies. 
     &lt;Sixteenth Technical Feature&gt; 
     A sixteenth technical feature disclosed in the present specification provides a mobile telephone comprising: a cartilage conduction vibration unit; an air conduction generation unit; and selection means for making a selection between a state for generating, and a state for not generating, vibration from the air conduction generation unit. A variety of different uses are thereby made possible, and the ability to select the state for not generating vibration from the air conduction generation unit permits usage adapted to take the surroundings into consideration and/or adapted for privacy protection. The air conduction generation unit may also be configured so as to have a hollow box structure, according to need, in a case where there is a desire for vigorously generated air conduction. 
     According to a specific feature, the air conduction generation unit is configured such that the air conduction generation unit is made to vibrate by the transmission of the vibration of the cartilage conduction vibration unit, and the transmission of vibration from the cartilage conduction vibration unit is cut off whenever the selection means is used to select the state for not generating vibration from the air conduction generation unit. It is thereby made possible to select between a state for generating, and a state for not generating, vibration from the air conduction generation unit using the cartilage conduction vibration unit as a vibration source. 
     According to a more specific feature, the mobile telephone includes a vibration conductor for relaying the vibration of the cartilage conduction vibration unit to the air conduction vibration unit, and the relay of vibration to the air conduction generation unit is cut off whenever the selection means is used to select the state for not generating vibration from the air conduction generation unit. In the case where such a vibration conductor is employed, it becomes possible to select between a state for generating, and a state for not generating, vibration from the air conduction generation unit even though the cartilage conduction vibration unit and the air conduction generation unit are affixed together. 
     According to another specific embodiment, there is a sliding function by which the selection means can slide between a position for generating, and a position for not generating, the vibration from the air conduction generation unit. According to yet another specific feature, there is a rotation function by which the selection means can be rotated between a position for generating, and a position for not generating, the vibration from the air conduction generation unit. In the cases where a mobile function is employed, it is also possible to configure such that at least a part of at least one of either the cartilage conduction vibration unit or the air conduction generation unit can be moved by the selection means. 
     According to another specific feature, the air conduction generation unit includes a vibration source, and the selection means stops the generation of vibration from the vibration source of the air conduction generation unit in the state for not generating the vibration from the air conduction generation unit. It is thereby possible to select whether or not air conduction is to be generated even in a configuration lacking moveable parts. 
     According to another specific feature, there is an environmental noise detection unit, and the selection means automatically selects the state for not generating the vibration from the air conduction generation unit whenever the environmental noise detected by the environmental noise detection unit is at or below a predetermined loudness. It is thereby possible to automatically select a state adapted to take the surroundings into consideration and/or adapted for privacy protection in the state where the surroundings are silent. 
     According to another feature, there is provided a mobile telephone comprising: an audio generation unit; a pressure sensor for detecting pressure on the audio generation unit; and an automatic adjustment unit for automatically changing the state of audio generated from the audio generation unit on the basis of the pressure detected by the pressure sensor. It is thereby possible to automatically change the state of audio generated from the audio generation unit on the basis of the natural operation of pressing the audio generation unit up against the ear. According to a specific feature, the audio generation unit is an air conduction speaker. According to another specific feature, the automatic adjustment unit automatically adjusts the volume or acoustics of the audio generated from the audio generation unit. 
     According to another specific feature, the automatic adjustment unit changes the state of audio generated in one direction from an initial state and maintains the changed state in accordance with an increase in pressure from the pressure sensor, and returns the state of audio generated to the initial state in accordance with a predetermined reduction or greater reduction in pressure from the pressure sensor. It is thereby possible to change the state of audio generated on the basis of a natural operation, and also to avoid an unintentional change in the state of audio generated. According to another specific feature, the automatic adjustment unit automatically changes the state of audio generated from the audio generation unit when a change in pressure from the pressure sensor continues for a predetermined period of time or longer, and does not respond to a change in pressure that does not meet the predetermined period of time. It is thereby possible to avoid an unintentional change in the state of audio generated. 
     According to another feature, there is provided a mobile telephone characterized by comprising a right ear audio generation unit, and a left ear audio generation unit arranged at a different position than that of the right ear audio generation unit. It is thereby possible to achieve a natural posture for holding the mobile telephone up against the ear. According to a specific feature, the right ear audio generation unit and the left ear audio generation unit are each arranged at two corner parts at the upper part of the mobile telephone. According to another specific feature, a large-screen display unit is arranged on the same surface on which the right ear audio generation unit and the left ear audio generation unit are arranged. According to another specific feature, each of the right ear audio generation unit and the left ear audio generation unit air conduction speakers. 
     According to another feature, there is provided a mobile telephone in which a large-screen display unit is provided, and air conduction speakers are provided to the corner parts at the upper part of the surface to which the large-screen display unit is provided. It is thereby possible to achieve a natural posture for effectively holding the air conduction speakers against the ear even while interference between the large-screen display unit and the face is avoided. 
     &lt;Seventeenth Technical Feature&gt; 
     A seventeenth technical feature disclosed in the present specification provides a mobile telephone comprising: a pair of cartilage conduction vibration units; a sound source signal unit; and drive units for driving each of the pair of cartilage conduction vibration units in a mutually phase-inverted waveform on the basis of a sound source signal from the sound source signal unit. It is thereby possible to obtain cartilage conduction by contact with each of the pair of cartilage conduction vibration units, and also thereby possible to substantially eliminate air conduction that is based on the vibration of the pair of cartilage conduction vibration units. 
     According to a specific feature, the pair of cartilage conduction vibration units is provided to each of the pair of corner parts at the upper part of the mobile telephone, which are suitable for contact against the ear cartilage. According to a further specific feature, elastic body units are provided to the pair of corner parts, and the pair of cartilage conduction vibration units is supported on the elastic body units. It is thereby possible to protect the cartilage conduction vibration units from collision with an external unit. 
     According to a further specific feature, the outer surface of the elastic body units is beveled so as to have a smoothly convex shape, thus achieving suitable contact with the ear cartilage. According to another specific feature, the cartilage conduction vibration units include a piezoelectric bimorph element or an electromagnetic vibrator. 
     According to another specific feature, the drive units are capable of switching between a mode for driving each of the pair of cartilage conduction vibration units in mutually inverted waveforms on the basis of a sound source signal from the sound source signal unit, and a mode for driving each of the pair of cartilage conduction vibration units in mutually identical waveforms on the basis of a sound source signal from the sound source signal unit. It is thereby possible to switch between eliminating and increasing air conduction. 
     According to yet another specific feature, there is an environmental noise detection unit, and the drive units drive each of the pair of the cartilage conduction vibration units in mutually inverted waveforms on the basis of a sound source signal from the sound source signal unit whenever the environmental noise detected by the environmental noise detection unit is at or below a predetermined loudness. It is thereby possible to automatically eliminate air conduction when the environment is silent. 
     According to yet another specific feature, it is possible to adjust the balance for driving each of the pair of cartilage conduction vibration units in mutually inverted waveforms on the basis of a sound source signal from the sound source signal unit. It is thereby possible to effectively eliminate air conduction and also to regulate the state where air conduction is eliminated. 
     According to yet another feature, the drive units are capable of driving only one of the pair of cartilage conduction vibration units. It is thereby possible to avoid driving uselessly when there is no need to eliminate air conduction. 
     According to a more specific feature, the mobile telephone includes an environmental noise detection unit, and the drive units drive each of the pair of cartilage conduction vibration units in mutually inverted waveforms on the basis of a sound source signal from the sound source signal unit whenever the environmental noise detected by the environmental noise detection unit is at or below a predetermined loudness, and drive only one of the pair of cartilage conduction vibration units whenever the environmental noise detected by the environmental noise detection unit is at or above a predetermined loudness. It is thereby possible to cause only the cartilage conduction vibration unit that is in contact with the ear cartilage to vibrate, and in such a state to cause the other cartilage conduction vibration unit to vibrate in an inverted waveform and automatically eliminate air conduction when the environment becomes silent. 
     According to another feature, there is provided a mobile telephone in which the cartilage conduction vibration units are provided to the pair of corner parts at the upper part of the mobile telephone, and the outer surface of the corner parts is beveled so as to have a smoothly convex shape. It is thereby made possible to make contact with the ear cartilage without incurring substantial pain and also possible to comfortably listen by cartilage conduction with the corner parts appropriately fitted to the cartilage around the external auditory meatus. 
     According to another feature, there is provided a mobile telephone comprising: a pair of cartilage conduction vibration units; a sound source signal unit; drive units capable of driving each of the pair of cartilage conduction vibration units on the basis of a sound source signal from the sound source signal unit; a selection unit for selecting a cartilage conduction vibration unit to be driven by a drive unit; and a controller for controlling the waveform inversion of the sound source signal from the sound source signal unit. The pair of cartilage conduction vibration units can thereby be used to achieve a variety of different forms of cartilage conduction. 
     &lt;Eighteenth Technical Feature&gt; 
     An eighteenth technical feature disclosed in the present specification provides a mobile telephone comprising a surface of the outer wall and a vibration source arranged inward from the surface of the outer wall, wherein when the vibration of the vibration source is transmitted to the surface of the outer wall, and the surface of the outer wall is brought into contact with at least a part of the ear cartilage around the entrance part of the external auditory meatus without making contact with the auricular helix, the sound pressure inside the external auditory meatus at about 1 cm from the entrance part of the external auditory meatus has an increase of at least 10 dB over that in the non-contact state. A mobile telephone in which it is possible to listen to sound by cartilage conduction can thereby be provided. 
     According to another feature, there is provided a mobile telephone comprising an surface of the outer wall and a vibration source arranged inward from the surface of the outer wall, wherein when the vibration of the vibration source is transmitted to the surface of the outer wall, and the surface of the outer wall is brought into contact with at least a part of the ear cartilage around the entrance part of the external auditory meatus without making contact with the auricular helix, the sound pressure inside the external auditory meatus at about 1 cm from the entrance part of the external auditory meatus changes by at least 5 dB due to the change in contact pressure. A mobile telephone by which the volume can be changed by a change in contact pressure during cartilage conduction can thereby be provided. 
     According to another feature, there is provided a mobile telephone comprising an surface of the outer wall and a vibration source arranged inward from the surface of the outer wall, wherein when the vibration of the vibration source is transmitted to the surface of the outer wall, and the entrance part of the external auditory meatus is occluded by the surface of the outer wall being brought into contact with at least a part of the ear cartilage around the entrance part of the external auditory meatus without contact being made with the auricular helix, the sound pressure in the external auditory meatus at about 1 cm from the entrance part of the external auditory meatus has an increase of at least 20 dB compared to the non-contact state. A mobile telephone by which it is possible to listen to sound by the earplug bone conduction effect during cartilage conduction can thereby be provided. 
     According to the specific features above, the sound pressure that is increased or changed is at 1,000 Hz. 
     According to yet another feature, the increase or change in sound pressure is in a state where the output of the vibration source is not changed. The sound pressure is thereby increased or changed without the volume being altered. 
     According to another specific feature, the state where the surface of the outer wall is brought into contact with at least a part of the ear cartilage around the entrance part of the external auditory meatus without making contact with the auricular helix is a state where the surface of the outer wall is brought into contact with the outside of the tragus. According to a more specific feature, the state where the sound pressure in the external auditory meatus at about 1 cm from the entrance part of the external auditory meatus is increased by at least 10 dB when the surface of the outer wall is brought into contact with at least a part of the ear cartilage around the entrance part of the external auditory meatus without making contact with the auricular helix, compared to the non-contact state, is one where the contact pressure of the surface of the outer wall against the outside of the tragus is 250 g. 
     According to another specific feature, the vibration source is arranged such that the vibration thereof is transmitted to the surface of the corner parts of the outer wall, and the state where the surface of the outer wall is brought into contact with at least a part of the ear cartilage around the entrance part of the external auditory meatus without making contact with the auricular helix is a state where the surface of the corner parts of the outer wall is brought into contact with the outside of the tragus. It is thereby possible to achieve contact suitable for obtaining cartilage conduction in the mobile telephone. 
     According to a more specific feature, the corner parts of the outer wall are constituted of a different material from the other portions of the outer wall. According to another more specific feature, the vibration source is either held inside the outer wall at the corner parts of the outer wall or is held inside the corner parts of the outer wall. 
     According to another feature, there is provided a mobile telephone comprising a surface of an outer wall, a vibration source arranged inward from the surface of the outer wall, and volume adjustment means, the vibration of the vibration source being transmitted to the surface of the outer wall and sound being listened to by the contact of the surface of the outer wall with at least a part of the ear cartilage around the entrance part of the external auditory meatus without contact with the auricular helix, wherein: in a room where the noise level (the A-weighted sound pressure level) is 45 dB or less, the mobile telephone being brought into proximity with the entrance part of the external auditory meatus and the surface of the outer wall being arranged so as to not be in contact, the volume is minimized and pure sound at 1,000 HZ is generated from the vibration source, and also narrow-band noise (⅓ octave-band noise) at a marginal level where the pure sound at 1,000 Hz is masked and cannot be heard is generated from a loudspeaker at a position separated from the entrance part of the external auditory meatus by 1 m. When the narrow-band noise at 1,000 Hz is subsequently increased by 10 dB from the marginal level, bringing the surface of the outer wall into contact with at least a part of the ear cartilage around the entrance part of the external auditory meatus without making contact with the auricular helix makes it possible to listen to pure sound at 1,000 Hz without the need to adjust or change the volume adjusting means. A mobile telephone in which the volume can be changed by a change in contact pressure during cartilage conduction can thereby be provided. 
     According to another feature, there is provided a mobile telephone comprising a surface of an outer wall, a vibration source arranged inward from the surface of the outer wall, and volume adjustment means, the vibration of the vibration source being transmitted to the surface of the outer wall and sound being listened to by the contact of the surface of the outer wall with at least a part of the ear cartilage around the entrance part of the external auditory meatus without contact with the auricular helix, wherein: in a room where the noise level (the A-weighted sound pressure level) is 45 dB or less, the mobile telephone being brought into proximity with the entrance part of the external auditory meatus and the surface of the outer wall being arranged so as to not be in contact, the volume is minimized and pure sound at 1,000 HZ is generated from the vibration source, and also narrow-band noise (⅓ octave-band noise) at a marginal level where the pure sound at 1,000 Hz is masked and cannot be heard is generated from a loudspeaker at a position separated from the entrance part of the external auditory meatus by 1 m. When the narrow-band noise at 1,000 Hz is subsequently increased by 20 dB from the marginal level, bringing the surface of the outer wall into contact with at least a part of the ear cartilage around the entrance part of the external auditory meatus without making contact with the auricular helix to occlude the entrance part of the external auditory meatus makes it possible to listen to pure sound at 1,000 Hz without the need to adjust or change the volume adjusting means. 
     &lt;Nineteenth Technical Feature&gt; 
     A nineteenth technical feature disclosed in the present specification provides a sound output device in which the vibration of a vibration source arranged inward from the surface of an outer wall is transmitted to the surface of the outer wall, and sound is listened to by the contact of the surface of the outer wall with at least a part of the ear cartilage around the entrance part of the external auditory meatus, wherein the vibration source causes there to be generated, from the surface of the outer wall, air conduction of a frequency characteristic trending inversely with respect to the frequency characteristic during cartilage conduction. It is thereby possible for the frequency characteristic during cartilage conduction and the frequency characteristic of the vibration source to be complementary to each other and, as a result, for the frequency characteristic of the sound reaching the tympanic membrane to approach flatness. 
     According to a specific feature, the average air conduction generated by the vibration source from the surface of the outer wall from 500 Hz to 1 kHz is 5 dB less than the average air conduction generated by the vibration source from the surface of the outer wall from 1 kHz to 2.5 kHz. 
     According to another specific feature, the sound output device is provided with an equalizer for correcting the frequency characteristic in consideration of the frequency characteristic specific to cartilage conduction in regard to the vibration source is driven by a sound source signal of the sound source signal output unit. It is thereby made possible for frequency characteristic of the sound reaching the tympanic membrane to approach flatness in consideration of the frequency characteristic of the cartilage conduction. 
     According to a more specific feature, the equalizer corrects for the frequency characteristic, which is different from when the external auditory meatus is in an open state, when the vibration source is driven in the state where the external auditory meatus is occluded. It is thereby made possible for the frequency characteristic of the sound reaching the tympanic membrane to approach flatness in consideration of the frequency characteristic of cartilage conduction during the state where the earplug bone conduction effect occurs. 
     According to another specific feature, there is a low-pass filter for correcting the frequency characteristic in consideration of the frequency characteristic specific to cartilage conduction in terms of the manner in which the vibration source is driven by a sound source signal of the sound source signal output unit. According to a further specific feature, the low-pass filter trims frequencies at 2.5 kHz and higher when the sound output device is used in a mobile telephone. In yet another specific feature, the low-pass filter trims frequencies at 10 kHz and higher when the sound output device is used in an audio device. Concern can thereby be given to the surroundings during, for example, silence. 
     According to another feature, there is provided a sound output device which includes a sound source signal output unit for outputting a sound source signal, a surface of an outer wall, a vibration source arranged inward from the surface of the outer wall and driven by the sound source signal from the sound source signal output unit, and an air conduction generation unit drive by the sound source signal from the sound source signal output unit, wherein the air conduction generated by the transmission of the vibration of the vibration source to the surface of the outer wall has a different frequency characteristic from that of the air conduction generated form the air conduction generation unit, it being possible to listen to sound by direct air conduction generated from the air conduction generation unit or by air conduction through cartilage conduction when the surface of the outer wall is brought into contact with at least a part of the ear cartilage around the entrance part of the external auditory meatus. The uncomfortable change in acoustics depending on the manner in which sound is being listened to can thereby be attenuated. 
     According to another feature, there is provided a sound output device which includes a sound source signal output unit for outputting a sound source signal, a surface of an outer wall, a vibration source arranged inward from the surface of the outer wall and driven by the sound source signal from the sound source signal output unit, and an air conduction generation unit drive by the sound source signal from the sound source signal output unit, wherein the frequency characteristic of the drive signal when the vibration source is driven by the sound source signal is different from the frequency characteristic of the drive signal when the air conduction generation unit is driven by the sound source signal, it being possible to listen to sound by direct air conduction generated from the air conduction generation unit or by air conduction through cartilage conduction when the surface of the outer wall is brought into contact with at least a part of the ear cartilage around the entrance part of the external auditory meatus. The uncomfortable change in acoustics depending on the manner in which sound is being listened to can thereby be attenuated. 
     According to another feature, there is provided a sound output device which includes a vibration source arranged inward from the surface of an outer wall, a sound source signal output unit for outputting a sound source signal, and an equalizer for correcting the frequency characteristic in consideration of the frequency characteristic specific to cartilage conduction in regard to the vibration source being driven by the sound source signal of the sound source signal unit, wherein the vibration of the vibration source is transmitted to the surface of the outer wall, and the surface of the outer wall is brought into contact with at least a part of the ear cartilage around the entrance part of the external auditory meatus, whereby it is possible to listen to sound. It is thereby possible for consideration to be given to the frequency characteristic during cartilage conduction and, as a result, for the frequency characteristic of sound reaching the tympanic membrane to approach flatness. According to a specific feature, the equalizer corrects for the frequency characteristic, which is different from when the external auditory meatus is in an open state, in regard to driving of the vibration source in the state where the external auditory meatus is occluded. According to a more specific feature, the sound output device is provided with a detection unit for detecting whether or not the external auditory meatus is in an occluded state, and the equalizer automatically switches to the state where the frequency characteristic is corrected, on the basis of the detection by the detection unit. According to another more specific feature, the sound output device is provided with a low-pass filter for correcting the frequency characteristic in consideration of the frequency characteristic specific to cartilage conduction in regard to driving of the vibration source by the sound source signal of the sound source signal unit, and, when the equalizer corrects the frequency characteristic in the state where the external auditory meatus is occluded, the state is considered not to be silent, and the low-pass filter is made not to function. 
     According to another feature, there is provided a sound output device which includes a vibration source arranged inward from the surface of an outer wall, a sound source signal output unit for outputting a sound source signal, and a low-pass filter for correcting the frequency characteristic in consideration of the frequency characteristic specific to cartilage conduction in regard to driving of the vibration source by the sound source signal of the sound source signal output unit, wherein the vibration of the vibration source is transmitted to the surface of the outer wall, and the surface of the outer wall is brought into contact with at least a part of the ear cartilage around the entrance part of the external auditory meatus, whereby it is possible to listen to sound. Concern can thereby be given to the surroundings during, for example, silence. According to a specific feature, it is possible to switch between whether or not the low-pass filter is made to function. It is thereby possible to provide support for times of silence and to properly use an emphasis on acoustics. According to a more specific feature, the sound output device is provided with an environmental noise detection unit for detecting environmental noise, and there is an automatic switch for whether or not the low-pass filter is made to function, on the basis of the detection results from the environmental detection unit. 
     According to another feature, there is provided a sound output device which includes a vibration source arranged inward from the surface of an outer wall, and a sound source signal output unit for outputting a sound source signal, wherein the vibration of the vibration source is transmitted to the surface of the outer wall, and the surface of the outer wall is brought into contact with at least a part of the ear cartilage around the entrance part of the external auditory meatus, whereby it is possible to listen to sound; the sound output device being characterized in that the frequency characteristic is different when the external auditory meatus is in an occluded state and when the external auditory meatus is in an open state, in regard to driving of the vibration source by the sound source signal of the sound source signal output unit. It is thereby possible to reduce the discomfort arising from the presence or absence of the earplug bone conduction effect. 
     &lt;Twentieth Technical Feature&gt; 
     A twentieth technical feature disclosed in the present specification provides a mobile telephone comprising: a cartilage conduction vibration source; an outer surface having no localized projections; a cartilage contact unit on the outer surface, to which the vibration of the cartilage conduction vibration source is transmitted such that the amplitude or the acceleration of the vibration reaches a maximum; and a cartilage non-contact unit on the outer surface exhibiting an amplitude or acceleration of vibration less than that at the cartilage contact unit. The vibration energy of the cartilage conduction vibration source is thereby concentrated on the cartilage contact unit and the dispersion to the cartilage non-contact unit is thereby reduced. The usage of the mobile telephone will also not be hindered, because the cartilage contact unit is set to the outer surface having no localized projections. 
     According to another feature, there is provided a mobile telephone comprising: a cartilage conduction vibration source; an outer surface; a cartilage contact unit on the outer surface, which is set to a position removed from both the central up-down axis and central left-right axis of the outer surface and to which the vibration of the cartilage conduction vibration source is transmitted such that the amplitude or the acceleration of the vibration reaches a maximum; and a cartilage non-contact unit on the outer surface exhibiting an amplitude or acceleration of vibration less than that at the cartilage contact unit. Because the cartilage contact unit is set to a position removed from both the central up-down axis and the central left-right axis of the outer surface, the resulting arrangement is suitable for contact with the ear cartilage at the entrance part of the external auditory meatus. 
     According to a specific feature, the cartilage contact unit is set to a corner part of the upper part of the mobile telephone. The resulting configuration is thereby suitable for bringing the surface of the outer wall into contact with at least a part of the ear cartilage around the entrance part of the external auditory meatus without making contact with the auricular helix. 
     According to a more specific feature, cartilage contact units are set in each of the pair of corner parts at the upper part of the mobile telephone. It is thereby possible to concentrate the vibration energy of the cartilage conduction vibration source on the ear cartilage both when the mobile telephone is held up against the right ear and when the mobile telephone is held up against the left ear. 
     According to another specific feature, the amplitude or the acceleration of vibration in the cartilage non-contact unit is ¼ or less the acceleration of vibration in the cartilage contact unit. The vibration energy of the cartilage conduction vibration source can thereby be concentrated on the cartilage contact unit and the dispersion to the cartilage non-contact unit can thereby be reduced. 
     According to another specific feature, the amplitude or the acceleration of vibration in the cartilage non-contact unit reduces monotonically as the distance from the cartilage contact unit increases. The vibration energy of the cartilage conduction vibration source can thereby be concentrated on the cartilage contact unit and the dispersion to the cartilage non-contact unit can thereby be reduced. 
     According to another feature, there is provided a mobile telephone comprising: a cartilage conduction vibration source; a chassis; a cartilage contact unit for holding the cartilage conduction vibration source so as not to be in contact with the chassis; and an anti-vibration material interposed between the cartilage contact unit and the chassis of the mobile telephone. The vibration energy of the cartilage conduction vibration source can thereby be concentrated on the cartilage contact unit. 
     According to a more specific feature, the aforesaid cartilage contact unit is constituted of a hard material, and the aforesaid anti-vibration material is constituted of an elastic body. The vibration energy of the cartilage conduction vibration source can thereby be concentrated on the cartilage contact unit. 
     As another element for concentrating the vibration energy of the cartilage conduction vibration source onto the cartilage contact unit, it is also suitable: to avoid the primary vibration direction of the cartilage conduction vibration source and support the same on the chassis of the mobile telephone; to reduce the surface area of contact between the cartilage contact unit and the chassis of the mobile telephone supporting the same; to limit the position at which the cartilage conduction vibration source is held to the vicinity of the cartilage contact unit; to make the cartilage contact material of a different material from that of the chassis of the mobile telephone; and the like. In addition to the cases of the independent usage of such elements, it is also possible to employ an appropriate combination of a plurality of elements. 
     According to another feature, there is provided a mobile telephone comprising: a cartilage conduction vibration source; a T-coil; and a controller for preventing the cartilage conduction vibration source from vibrating whenever the T-coil is being used. The greater discomfort that occurs compared to listening to sound using the T-coil is thereby prevented, and the unnecessary consumption of power by cartilage conduction when the T-coil is operating is thereby prevented. In the description above, in a preferred configuration, to prevent accidental conflation where cartilage conduction is turned off in tandem when the T-coil is turned on by a mistaken operation, the T-coil will not turn on unless a special operation is intentionally done. 
     &lt;Twenty-First Technical Feature&gt; 
     A twenty-first technical feature disclosed in the present specification provides a mobile telephone comprising: a telephone function unit; a cartilage conduction vibration unit; an application processor for controlling the telephone function unit; a power management unit for supplying a plurality of different voltages to the telephone function unit; a drive circuit for driving the cartilage conduction vibration unit on the basis of the power supplied from the power management; and a controller for controlling the power management unit and the drive circuit on the basis of an instruction from the application processor. The cartilage conduction vibration unit can thereby be driven directly, and power voltage can be supplied to the cartilage conduction vibration unit integratedly with the supply of power voltage to the various constituent elements inside the mobile telephone, other integrated forms of control also being possible as well. According to a more specific feature, the power management unit, the drive circuit, and the controller are configured as a single-chip integrated circuit. 
     According to another specific feature, the drive circuit has a boosted-voltage circuit, and the integrated circuit has a connective terminal for external attachment of a condenser for the boosted-voltage circuit. The cartilage conduction vibration element (piezoelectric bimorph) can thereby be driven without the need to add a separate chip for the boosted-voltage circuit. 
     According to another specific feature, the mobile telephone is controlled by a controller and has a cartilage conduction acoustic signal processing for an audio signal for driving the cartilage conduction vibration unit. It is thereby possible to integrate the control of the power management with the control for acoustic processing. Accordingly, the mobile telephone can be endowed with a suitable cartilage conduction function merely by a normal audio signal being inputted to the integrated IC and the cartilage conduction vibration unit being connected to the integrated IC. According to a more specific feature, the power management unit, the drive circuit, the controller, and the cartilage conduction acoustic signal processing unit are configured as a single-chip integrated circuit. 
     According to another specific feature, the mobile telephone includes a speaker, a microphone, and an analog front-end unit by which the speaker and microphone are connected, the analog front-end unit being controlled by the controller. The output of audio signals can thereby be collectively switched and adjusted. Specifically, the transfer of digital control signals between the integrated IC and the application processor, the digital control signals relating to the functions of the overall mobile telephone inclusive of the functions of the cartilage conduction vibration unit, can be integrated with the transfer of analog audio signals between the integrated IC and the application processor. According to a more specific feature, the analog front-end unit switches between driving the cartilage conduction vibration unit and driving the speaker on the basis of the control by the controller. According to another more specific feature, the power management unit, the drive circuit, the controller, the cartilage conduction acoustic signal processing unit, and the analog front-end unit are configured as a single-chip integrated circuit. 
     According to another feature, there is provided a mobile telephone comprising: a telephone function unit; a cartilage conduction vibration unit; an application processor for controlling the telephone function unit; a power management unit for supplying a plurality of different voltages to the telephone function unit; a cartilage conduction acoustic signal processing unit for an audio signal for driving the cartilage conduction vibration unit; and a controller for controlling the power management unit and the cartilage conduction acoustic signal processing unit on the basis of an instruction from the application processor. The control for acoustic processing relating to cartilage conduction can thereby be integrated with the control for power management. According to a specific feature, the power management unit, the cartilage conduction acoustic signal processing unit, and the controller are configured as a single-chip integrated circuit. 
     According to another specific feature, the mobile telephone has a speaker, a microphone, and an analog front-end unit by which the speaker and microphone are connected, the analog front-end unit being controlled by the controller. The output of audio signals can thereby be collectively switched and adjusted. According to a more specific feature, the analog front-end unit switches between driving the cartilage conduction vibration unit and driving the speaker on the basis of the control by the controller. According to yet another more specific feature, the power management unit, the cartilage conduction acoustic signal processing unit, the controller, and the analog-front end unit are configured as a single-chip integrated circuit. 
     According to another feature, there is provided a single-chip integrated circuit which includes: a power management unit for supplying a plurality of different voltages for telephone functions; a connecting part by which a cartilage conduction vibration element, which is one of the constituent elements of the cartilage conduction vibration unit, is connected; a drive circuit for driving the cartilage conduction vibration unit on the basis of the power supplied from the power management; and a controller for controlling the power management unit and the drive circuit on the basis of digital data from an external unit. The cartilage conduction vibration unit can thereby be driven directly, and power voltage can be supplied to the cartilage conduction vibration unit integratedly with the supply of power voltage to the various constituent elements inside the mobile telephone, it being possible to also integrate the control thereof. 
     According to a specific feature, the drive circuit has a boosted-voltage circuit, and the integrated circuit has a connective terminal for external attachment of a condenser for the boosted-voltage circuit. The cartilage conduction vibration element (piezoelectric bimorph) can thereby be driven merely by the single-chip integrated circuit. 
     According to another specific feature, the single-chip integrated circuit is controlled by the controller and has a cartilage conduction acoustic signal processing unit for an audio signal for driving the cartilage conduction vibration unit. It is thereby possible to integrate the control of the power management with the control for acoustic processing. According to another specific feature, the single-chip integrated circuit includes a connecting part for the speaker, a connecting part for the microphone, and an analog front-end unit connected to each of the connecting parts, the analog front-end unit being controlled by the controller. According to a more specific feature, the analog front-end unit switches between driving the cartilage conduction vibration unit and driving the speaker on the basis of the control by the controller. 
     According to another feature, there is provided a single-chip integrated circuit which includes: a power management unit for supplying a plurality of different voltages for telephone functions; a connecting part by which a cartilage conduction vibration element, which is one of the constituent elements of the cartilage conduction vibration unit, is connected; an audio signal acoustic processing unit for an audio signal for driving the cartilage conduction vibration unit; and a controller for controlling the power management unit and the cartilage conduction acoustic signal processing unit on the basis of digital data from an external unit. According to a specific feature, the single-chip integrated circuit includes a connecting part for the speaker, a connecting part for the microphone, and an analog front-end unit connected to each of the connecting parts, the analog front-end unit being controlled by the controller. According to a more specific feature, the analog front-end unit switches between driving the cartilage conduction vibration unit and driving the speaker on the basis of the control by the controller. 
     &lt;Twenty-Second Technical Feature&gt; 
     A twenty-second technical feature disclosed in the present specification provides a mobile telephone comprising: a cartilage conduction vibration source provided inside a chassis; and an elastic body integrally affixed to and covered by the exterior of the chassis. The vibration of the chassis of the mobile telephone is thereby suppressed and sound leakage due to the generation of air conduction sound is thereby attenuated. According to a specific feature, the mobile telephone has a cartilage conduction unit for conducting the vibration of the cartilage conduction vibration source and for making contact with the ear cartilage, it being thus possible to listen to sound by cartilage conduction even while sound leakage to the surroundings due to the generation of air conduction sound is attenuated. 
     According to a more specific feature, the cartilage conduction unit is an elastic body. The elastic body has an acoustic impedance approximating that of ear cartilage, wherefore it is possible to listen to sound by cartilage conduction even when sound leakage to the surroundings due to the generation of air conduction sound is attenuated. According to a further specific feature, the cartilage conduction unit can be an elastic body integrally affixed to and covered by the exterior of the chassis. More specifically, the cartilage conduction unit can be connected with an elastic body integrally affixed to and covered by the exterior of the chassis. 
     According to another specific feature, the cartilage conduction unit is a rigid body, and the elastic body also covers the cartilage conduction unit. Sound leakage to the surroundings due to the generation of air conduction sound can thereby be attenuated even while favorable cartilage conduction is obtained. According to a more specific feature, the cartilage conduction unit is supported on the chassis via a vibration isolation material, and the transmission of vibrations to the chassis is attenuated. According to a further specific feature, the vibration isolation material is an elastic body of the same material as the elastic body integrally affixed to and covered by the exterior of the chassis. 
     According to another specific feature, the cartilage conduction vibration source is supported on the cartilage conduction unit in a state of non-contact with the chassis, and the direct transmission of vibration from the cartilage conduction vibration source to the chassis is avoided. In the case where priority is given to structural simplicity, it is also possible for the cartilage conduction vibration source to be supported on the chassis. The chassis will then have greater vibration, but such vibration can be attenuated by the elastic body integrally affixed to and covered by the exterior of the chassis. 
     According to another feature, there is provided a mobile telephone comprising: an elastic body integrally affixed to and covered by the exterior of the chassis, and a cartilage conduction vibration source supported by the elastic body in a state of non-contact with the chassis. It is thereby possible to attenuate sound leakage to the surroundings due to the generation of air conduction sound even while avoiding the direct transmission of vibration from the cartilage conduction vibration source to the chassis, and to listen to sound by cartilage conduction. 
     According to a specific feature, the cartilage conduction vibration source is supported on the inside of the elastic body, and the outside of the elastic body at the part supporting the cartilage conduction vibration source serves as a cartilage conduction unit for making contact with the ear cartilage. According to a further specific feature, the cartilage conduction vibration source is supported on the inside of the elastic body via a rigid support unit. 
     According to another specific feature, the mobile telephone has a support structure for supporting the internal configuration of the mobile telephone on the chassis from the inside such that the weight thereof vibrates integrally. The vibration from the interior and the exterior of the chassis of the mobile telephone can thereby be suppressed. 
     According to another feature, there is provided a mobile telephone comprising: a cartilage conduction vibration source provided to the interior of a chassis; and a support structure for supporting the internal configuration of the mobile telephone on the chassis from the inside such that the weight thereof vibrates integrally. The vibration of the chassis of the mobile telephone is thereby suppressed and sound leakage due to the generation of air conduction sound is thereby attenuated. Internal configurations contributing to the above include a battery. 
     According to a specific feature, the mobile telephone has a finely subdividing structure for finely subdividing surplus space of the interior of the chassis. The vibration of the chassis of the mobile telephone can thereby be suppressed and the air inside the chassis prevented from resonating, and the generation of air conduction sound can thereby be attenuated. 
     According to another feature, there is provided a mobile telephone comprising: a cartilage conduction vibration source provided to the interior of a chassis, and a finely subdividing structure for finely subdividing the surplus space of the interior of the chassis. The air inside the chassis can thereby be prevented from resonating, and the generation of air conduction sound can thereby be attenuated. An example of a finely subdividing structure is a barrier wall. Another example of a finely subdividing structure is a nonwoven cloth packed inside the chassis. 
     [Twenty-Third Technical Feature] 
     A twenty-third technical feature disclosed in the present specification provides a sound output device having: a chassis; a cartilage conduction unit defining a convex face shape on the chassis surface; and a cartilage conduction vibration source for transmitting vibration to the cartilage conduction unit. In so doing, the cartilage conduction unit arranged touching the ear is naturally accommodated within the ear, affording contact with the ear cartilage over a wide surface area. 
     The ear-contacting part of an ordinary telephone handset has a concave face in order to form a closed space to the front of the ear; however, the handset for cartilage conduction according to the present invention conversely has a convex face, providing a natural shape that readily conforms to the ear in the aforedescribed manner. 
     According to a specific feature, the cartilage conduction unit has a convex face shape fitting into a depression of ear having the external auditory meatus opening as the bottom. According to a more specific feature, the cartilage conduction unit has a convex face shape, the apex of which enters the external auditory meatus opening. According to a yet more specific feature, the cartilage conduction unit has a conical shape. According to another yet more specific feature, the cartilage conduction unit has a spherical face shape. 
     According to another specific feature, the cartilage conduction vibration source transmits vibration from the inside of a cartilage conduction unit which is situated inside the chassis. In so doing, desired vibration can be propagated to a cartilage conduction unit defining a convex face shape at the chassis surface. Optionally, a space to the inside of the cartilage conduction unit defining a convex face shape can be utilized when situating the cartilage conduction vibration source. 
     According to a more specific feature, a support part is furnished for the purpose of supporting the cartilage conduction vibration source, and transmitting vibration thereof to the inside of a cartilage conduction unit. In so doing, support of the cartilage conduction vibration source and transmission of vibration to the inside of the cartilage conduction unit can be achieved. 
     According to a more specific feature, the support part supports a center part of the cartilage conduction vibration source. According to another more specific feature, the support part supports an end part of the cartilage conduction vibration source. In so doing, effective vibration of the cartilage conduction vibration source and transmission thereof can be achieved. 
     According to another specific feature, the sound output device is configured as a handset of a land-line telephone. In the present invention, the configuration of a cartilage conduction unit defining a convex face shape at the chassis surface is suitable for implementation in a handset of a land-line telephone. 
     According to another specific feature, a stereo audio output device is configured from a pair of sound output devices. In this way, a configuration of a cartilage conduction unit defining a convex face shape at the chassis surface is suited to sound output from a stereo audio output device. 
     According to another feature, there is provided a sound output device having a cartilage conduction unit defining a convex face of conical shape, and a cartilage conduction vibration source for transmitting vibration to a cartilage conduction unit. This conical shape is configured on the presumption that a conical side face will contact the entire circumference of the external auditory meatus opening in satisfactory fashion when the distal end thereof is inserted into the external autidory meatus opening; the depth to which the cone is inserted into the external auditory meatus opening does not have a large influence on cartilage conduction, and a state of constant satisfactory contact of the cartilage conduction unit against the entire circumference of the external auditory meatus can be achieved, regardless of individual differences in the size of the external auditory meatus opening. By employing such a pair of sound output devices which wrap around from the left and right to respectively press against the external auditory meatus opening of each ear, a satisfactory configuration for a stereo audio device can be achieved. 
     According to another feature, there is provided a sound output device having a cartilage conduction unit, and cartilage conduction vibration sources including a plurality of vibration sources having different frequency characteristics, for transmitting vibration to the cartilage conduction unit. By employing a plurality of cartilage conduction vibration sources of different frequency characteristics in complementary fashion in this way, the frequency characteristics of the cartilage conduction unit can be improved. An example of a plurality of vibration sources employed in complementary fashion is a combination of a low-end element and a high-end element. 
     [Twenty-Fourth Technical Feature] 
     A twenty-fourth technical feature disclosed in the present specification provides a mobile telephone having a right-ear cartilage conduction unit, a left-ear cartilage conduction unit, a linking unit for linking the right-ear cartilage conduction unit and the left-ear cartilage conduction unit, and a cartilage conduction vibration source for transmitting vibration to the right-ear cartilage conduction unit or to the left-ear cartilage conduction unit. This linking unit has various useful functions. 
     According to a specific feature, the linking unit provides rigid joining of the right-ear cartilage conduction unit and the left-ear cartilage conduction unit. In so doing, the relative positional relationship of the right-ear cartilage conduction unit and the left-ear cartilage conduction unit can be stabilized, and the right-ear cartilage conduction unit and the left-ear cartilage conduction unit attached to a mobile telephone in a stable manner. According to a more specific feature, the right-ear cartilage conduction unit, the left-ear cartilage conduction unit, and the linking unit are provided as a practical component integrally formed from a hard material. 
     According to another specific feature, a vibration isolating part is furnished between the right-ear cartilage conduction unit, the left-ear cartilage conduction unit, and the linking unit, and the chassis of the mobile telephone. This vibration isolating part is useful in reducing sound leakage to the surrounding area arising from air conduction occurring when vibration is transmitted to the chassis. According to a more specific feature, the vibration isolating part is formed of an elastomer material. Typically, higher vibration isolating effect is obtained with a vibration isolating part that is softer and thicker, but on the other hand, doing so makes the hold on the right-ear cartilage conduction unit and the left-ear cartilage conduction unit unstable. In accordance with this feature, by providing a rigid joint between the right-ear cartilage conduction unit and the left-ear cartilage conduction unit through the linking unit, the relative positions of both can be maintained, and both can be attached in more stable fashion to the chassis. 
     According to another specific feature, the linking unit transmits vibration between the right-ear cartilage conduction unit and the left-ear cartilage conduction unit. Various useful functions can be obtained by doing so. According to a more specific feature, a cartilage conduction vibration source is joined to either the right-ear cartilage conduction unit or the left-ear cartilage conduction unit, and the linking unit transmits vibration of the cartilage conduction vibration source from the right-ear cartilage conduction unit or the left-ear cartilage conduction unit, whichever has the cartilage conduction vibration source joined thereto, to the unjoined unit. In so doing, useful cartilage conduction can also be obtained from the cartilage conduction unit to which the cartilage conduction vibration source is not joined. 
     According to another more specific feature relating to transmission of vibration between the right-ear cartilage conduction unit and the left-ear cartilage conduction unit by the linking unit, the cartilage conduction vibration source includes a first vibration source and a second vibration source respectively joined to the right-ear cartilage conduction unit and the left-ear cartilage conduction unit, and the linking unit mixes vibration of the first vibration source and the second vibration source. According to another more specific feature, drive signals of mutually inverted waveform are presented to the first vibration source and the second vibration source, and the vibrations thereof are mixed, whereby generation of air-conducted sound through transmission of vibration to the chassis can be reduced. 
     According to another specific feature, the right-ear cartilage conduction unit, the left-ear cartilage conduction unit, and the linking unit are exposed at the mobile telephone surface. In so doing, the cartilage conduction structure can be concentrated at the mobile telephone surface, facilitating the layout of components inside the mobile telephone, as well as obtaining good cartilage conduction through contact from the outside. 
     According to a separate feature, the right-ear cartilage conduction unit and the left-ear cartilage conduction unit are exposed at the mobile telephone surface, while the linking unit is not exposed at the mobile telephone surface. In so doing, good cartilage conduction through contact of the right-ear cartilage conduction unit and the left-ear cartilage conduction unit from the outside can be obtained, and a high degree of freedom in linkage of the two can be achieved. 
     According to another specific feature, the linking unit links the right-ear cartilage conduction unit and the left-ear cartilage conduction unit while bypassing the internal configuration of the mobile telephone. The layout of components inside the mobile telephone can be facilitated thereby. An example of a configuration of the mobile telephone is an in-camera. In this case, the right-ear cartilage conduction unit, the left-ear cartilage conduction unit, and the in-camera, which are all preferably situated in an upper part of the mobile telephone, can be laid out with no interference. 
     According to another specific feature, the right-ear cartilage conduction unit and the left-ear cartilage conduction unit are respectively situated at two corners in an upper part of the mobile telephone. In so doing, contact against the ear cartilage in a natural manner can be achieved regardless of whether the mobile telephone is held in the right hand or held in the left hand, the aforedescribed preferred placement being achievable through the linking unit linking the right-ear cartilage conduction unit and the left-ear cartilage conduction unit. 
     According to another specific feature, there is provided a mobile telephone having a cartilage conduction unit, a cartilage conduction vibration source of elongated shape joined at one end to the cartilage conduction unit, and a weight attached to the other end of the cartilage conduction vibration source. The weight is not supported by any part other than this other end, and the inertia afforded by the load thereof is imparted to the other end of the cartilage conduction vibration source. 
     [Twenty-Fifth Technical Feature] 
     A twenty-fifth technical feature disclosed in the present specification provides an incoming-talk unit for a mobile telephone, having a cartilage conduction unit capable of contacting ear cartilage, an incoming call vibrator, and a short-range communication unit for communicating with the mobile telephone. In so doing, it is possible to be notified of and answer an incoming call while the mobile telephone remains stowed, for example, in a purse or the like; and during videoconferencing or the like, the risk of bothering others, or loss of privacy, due to the other caller&#39;s voice escaping to the surrounding area, can be prevented. According to a specific feature, the unit has a cartilage conduction vibration source for the cartilage conduction unit, and vibration of the cartilage conduction vibration source is employed concomitantly as a vibration source for the incoming call vibrator. 
     According to a specific feature, the incoming-talk unit is further with an outgoing-talk unit. Use as an outgoing-talk/incoming-talk unit is possible thereby. In cases of a compact configuration of such an outgoing-talk/incoming-talk unit, the outgoing-talk unit is preferably a bone conduction microphone. According to a more specific feature, the bone conduction microphone is situated at a location contacting the cheekbone when the cartilage conduction unit is placed in contact against the ear cartilage. 
     According to another specific feature, there is provided a mobile telephone having a cartilage conduction unit capable of contacting ear cartilage, an outgoing-talk unit, a telephone function unit, and a short-range communication unit for communicating with a mobile telephone, capable of independently making calls through the cartilage conduction unit, the outgoing-talk unit, and the telephone function unit, and provided with a cartilage conduction unit and an outgoing-talk unit through communication via the short-range communication unit, and capable of being used as an outgoing-talk/incoming-talk unit for another mobile telephone. In so doing, the various advantages afforded by cartilage conduction can be utilized during in calls made using another, ordinary mobile telephone. In this case, with a view to reasonable use in combination with another mobile telephone, it is preferable for the mobile telephone provided with the aforedescribed features to be configured as an ultra-compact mobile telephone. 
     According to a specific feature, the mobile telephone provided with the aforedescribed features has an incoming call vibrator, the mobile telephone being capable of being used as an incoming call vibrator unit for another mobile telephone, by being operated as an incoming call vibrator via the short-range communication unit. According to a more specific feature, the incoming call vibrator is set up so as to perform different incoming call vibration when there is an incoming call to the telephone function unit, versus when there is an incoming call to the other mobile telephone, transmitted by the short-range communication unit. 
     According to another specific feature, the mobile telephone provided with the aforedescribed features has a display unit, the display unit producing a different display when there is an incoming call to the telephone function unit, versus when there is an incoming call to the other mobile telephone, transmitted by the short-range communication unit. According to another specific feature, the mobile telephone provided with the aforedescribed features has an operating unit, and call answering is initiated through an identical operation performed by the operating unit, when there is an incoming call to the telephone function unit, and when there is an incoming call to the other mobile telephone, transmitted by the short-range communication unit. 
     According to a specific feature, there is provided a mobile telephone that comprises a first section and second section which are separable, the first section being furnished with an outgoing-talk unit, a telephone function unit, and a short-range communication unit for communicating with the second section, and the second section being furnished with a cartilage conduction unit capable of contacting ear cartilage and a short-range communication unit for communicating with the first section, and that functions as an integrated mobile telephone when the first section and the second section are joined, while when the second section is separated from the first section, the second section functions as a remote incoming-talk unit for short-range communication with the first section. In so doing, while the first section is kept stowed, for example, in a purse or the like, it is possible to receive incoming calls through the separated second section, as well as to prevent the risk of bothering others, or loss of privacy, due to the other caller&#39;s voice escaping to the surrounding area, during videoconferencing or the like. 
     According to a specific feature, the second section is furnished with an incoming call vibrator, and when the second section is separated from the first section, the second section functions as a remote incoming call vibrator for the first section. In so doing, it is possible to be notified of and answer incoming calls while keeping the separated second section on the body, for example, in a pocket or the like. According to a specific feature, the unit has a cartilage conduction vibration source for the cartilage conduction unit, and vibration of the cartilage conduction vibration source is employed concomitantly as a vibration source for the incoming call vibrator. 
     According to a specific feature, the first section and the second section are respectively furnished with an operating unit for performing a call answer operation, the operating unit of the second section being disabled when the first section and the second section are joined. According to another specific feature, the first section is furnished with an incoming-talk unit, the incoming-talk unit being disabled when the first section and the second section are joined. According to yet another specific feature, the second section is furnished with an outgoing-talk unit, the outgoing-talk unit being disabled when the first section and the second section are joined. According to a more specific feature, the outgoing-talk unit of the second section is a bone conduction microphone. 
     According to another specific feature, the first section and the second section are respectively furnished with charging means for performing charging of the second section from the first section. In so doing, when the first section is being charged while the first section and the second section are in the joined state, charging of the second section can take place simultaneously as well. According to a more specific feature, the device is configured such that the charging means detects whether or not the first section and the second section are in the joined state, and automatically switches between enabling and disabling functions of the aforedescribed units. 
     According to yet another specific feature, an elastic body is anchored to either the first section or the second section, and the first section or the second section is detachably attached to the other via the elastic body. In so doing, utilizing the separable configuration for the first section and the second section, vibration from the cartilage conduction unit of the second section is not readily propagated to the first section when the two are joined. According to a more specific feature, the elasticity of the elastic body is utilized for detachable attachment of the first section and the second section. 
     [Twenty-Sixth Technical Feature] 
     A twenty-sixth technical feature disclosed in the present specification provides a mobile telephone having a telephone function unit, a cartilage conduction unit, a cartilage conduction vibration source for vibrating the cartilage conduction unit, a power supply unit for supplying power to the cartilage conduction vibration source, and a power supply control unit for providing a supply of power to the power supply unit when the cartilage conduction unit is in a state able to contact ear cartilage, while halting the supply of power to the power supply unit when the cartilage conduction unit is in a state of non-contact with ear cartilage. Efficient supply of power to the cartilage conduction vibration source is possible thereby. 
     According to a specific feature, the mobile telephone has a power switch, and the state of non-contact of the cartilage conduction unit with ear cartilage refers to a state immediately following turning on of the power switch. According to another specific feature, the mobile telephone has a speaker for outputting sound during videoconferencing, and the state of non-contact of the cartilage conduction unit with ear cartilage refers to the videoconferencing mode state. 
     According to yet another specific feature, the state of non-contact of the cartilage conduction unit with ear cartilage refers to a non-talk state. More specifically, the power supply control unit initiates supply of power to the power supply unit in response to a call initiation signal, and halts the supply of power to the power supply unit in response to a call termination signal. 
     According to a more specific feature, the call initiation signal is an incoming call signal. According to another more specific feature, the call initiation signal is a call request signal. According to another more specific feature, the call termination signal is a call disconnect signal. 
     According to another specific feature, the power supply unit is a voltage booster circuit. According to another specific feature, the cartilage conduction vibration source is a piezoelectric bimorph element. These features are more preferable when combined. 
     According to yet another specific feature, the mobile telephone has an amplifier for providing a call signal to the cartilage conduction vibration source, and the power supply unit supplies power to this amp. According to a more specific feature, a muting circuit is inserted between the cartilage conduction vibration source and the amplifier, and muting is performed by the muting circuit, for predetermined time intervals before and after initiation and termination of supply of power to the power supply unit. More specifically, the power supply control unit initiates muting by the muting circuit, in response to call initiation signals and call termination signals. According to another specific feature, in the aforedescribed configurations, the power supply unit and the power supply control unit are preferably configured as a one-chip integrated circuit. 
     According to another feature, there is provided a mobile telephone having a telephone function unit, a cartilage conduction unit, a cartilage conduction vibration source for vibrating the cartilage conduction unit, a power supply unit for supplying power to the cartilage conduction vibration source, an amplifier for providing a call signal to the cartilage conduction vibration source, and a muting circuit inserted between the cartilage conduction vibration source and the amplifier, for muting for a predetermined time interval, and a muting control unit for initiating muting by the muting circuit, in response to call initiation signals and call termination signals. In so doing, it is possible to control power supply in such a way that popping noises are not produced by the cartilage conduction vibration source at initiation and termination of a call. 
     According to a specific feature, the call initiation signal is an incoming call signal. According to another more specific feature, the call initiation signal is a call request signal. According to another specific feature, the call termination signal is a call disconnect signal. 
     According to another specific feature, the mobile telephone has a power supply control unit that initiates or halts the supply of power to the power supply unit during intervals of muting by the muting circuit. According to another specific feature, in the aforedescribed configurations, the power supply unit, the power supply control unit, and the muting circuit are preferably configured as a one-chip integrated circuit. 
     According to another specific feature, in the aforedescribed configuration the power supply unit is a voltage booster circuit. According to another specific feature, the cartilage conduction vibration source is a piezoelectric bimorph element. These features are more preferable when combined. 
     [Twenty-Seventh Technical Feature] 
     A twenty-seventh technical feature disclosed in the present specification provides a mobile telephone in which a cartilage conduction unit for touching ear cartilage is furnished to a mobile telephone upper part, and a videoconferencing in-camera is furnished to a mobile telephone lower part. In so doing, the cartilage conduction unit and the videoconferencing in-camera can be situated effortlessly. According to a specific feature, the mobile telephone has a display screen, and the videoconferencing in-camera is furnished to the opposite side from the cartilage conduction unit with the display screen therebetween. 
     According to a more specific feature, the display screen is rectangular, and the videoconferencing in-camera is situated such that a direction perpendicular to the lengthwise sides of the display screen is a vertical direction. In so doing, image capture can take place in a satisfactory manner, while holding the mobile telephone in landscape mode oriented so that the lengthwise sides of the display screen are horizontal. According to another more specific feature, the display screen is rectangular, and the videoconferencing in-camera is furnished to the mobile telephone lower part and biased towards a location positioned to the upper side when the mobile telephone is held oriented so that the lengthwise sides of the display screen are horizontal. In so doing, the face of the user can be captured from above while holding the mobile telephone in landscape mode. 
     According to yet another specific feature, the mobile telephone has orientation detection means for detecting the orientation of the mobile telephone, and image auto-rotation means for rotating an image on the display screen by 90 degrees, on the basis of the orientation detection means, and is moreover furnished with misoperation prevention means for preventing misoperation of the image auto-rotation means on the basis of the videoconferencing in-camera being situated such that a direction perpendicular to the lengthwise sides of the display screen is a vertical direction. In so doing, confusion as to which way an image is pointing can be avoided, while the videoconferencing in-camera is situated such that a direction perpendicular to the lengthwise sides of the display screen is a vertical direction. 
     According to yet another specific feature, the mobile telephone has a piezoelectric bimorph element as the vibration source for the cartilage conduction unit, the piezoelectric bimorph element being adapted to detect the impact of a finger applied to the cartilage conduction unit while the mobile telephone is held in an orientation such that the lengthwise sides of the display screen are horizontal, thereby serving concomitantly as an operation input during videoconferencing. In so doing, the piezoelectric bimorph element can be effectively utilized as a vibration source for the cartilage conduction unit while held in landscape orientation. 
     According to yet another specific feature, the mobile telephone has a piezoelectric bimorph element as the vibration source for the cartilage conduction unit, vibration of the piezoelectric bimorph element being concomitantly employed to provide notification that videoconferencing is in progress, through vibration transmitted to a hand holding the mobile telephone with the lengthwise sides of the display screen horizontal. In so doing, the piezoelectric bimorph element can be effectively utilized as a vibration source for the cartilage conduction unit while held in landscape orientation. 
     According to another specific feature, a light-emitting unit is furnished in proximity to the videoconferencing in-camera, and the line of sight is directed towards the videoconferencing in-camera by emission of light from the light-emitting unit. In so doing, smooth videoconferencing at a natural line of sight can be achieved. 
     According to another feature, there is provided a mobile telephone that has a videoconferencing in-camera, and a main camera for capturing images from the opposite side in relation to the videoconferencing in-camera, and that during videoconferencing transmits an image from the main camera and an image from the videoconferencing in-camera. In so doing, it is possible to transmit images having richer information content. 
     According to another feature, there is provided a mobile telephone that has a videoconferencing in-camera, a main camera for capturing images from the opposite side relative to the videoconferencing in-camera, and a display screen, and that, during videoconferencing, displays on the display screen an image from the main camera and a received image from the videoconferencing in-camera. More accurate image transmission is possible thereby. 
     According to another feature, there is provided a mobile telephone that has a videoconferencing in-camera and a display screen, and that, during videoconferencing, displays on the display screen a received image from the videoconferencing in-camera, and a received image taken from the opposite side in relation to the videoconferencing in-camera. In so doing, it is possible to transmit images having richer information content. 
     According to another feature, there is provided a mobile telephone that has a videoconferencing in-camera, a main camera for capturing images from the opposite side relative to the videoconferencing in-camera, and a display screen, and that, during videoconferencing, displays on the display screen an image from the main camera and a received image taken from the opposite side in relation to the videoconferencing in-camera. In so doing, videoconferencing in which the callers share what they are looking at with one another are possible. 
     [Twenty-Eighth Technical Feature] 
     A twenty-eighth technical feature disclosed in the present specification provides a cartilage conduction vibration source device having a sound signal input unit for inputting a sound signal, an acoustic processing unit for acoustic processing, for purposes of cartilage conduction vibration, of the sound signal input from the sound signal input unit, a power source input unit, a voltage booster circuit unit for boosting an input voltage to the power source input unit, and an amplifier unit supplied with power by the voltage booster circuit unit, for outputting a processed signal processed by the acoustic processing unit, to the cartilage conduction vibration source as a drive signal. In so doing, it is possible for the cartilage conduction vibration source to be readily driven in a manner suited to cartilage conduction, by input of an ordinary sound signal and driving by an ordinary power source. 
     According to a specific feature, the sound signal input unit inputs an analog signal from an audio signal output unit, the acoustic processing unit and the amplifier unit are constituted by analog circuits, and an analog drive signal is output to the cartilage conduction vibration source. In so doing, the cartilage conduction vibration source can be readily driven in a manner suited to cartilage conduction, on the basis of sound output for an ordinary speaker. 
     According to another specific feature, the sound signal input unit inputs an analog signal from an audio signal output unit, the acoustic processing unit is constituted by an AD conversion circuit, a digital acoustic processing circuit, and a DA conversion circuit, and the amp circuit is constituted by an analog circuit which outputs the output of the DA conversion circuit to the cartilage conduction unit as an analog drive signal. In so doing, driving of the cartilage conduction vibration source in a manner suited to cartilage conduction on the basis of sound output for an ordinary speaker can be accomplished at low cost. 
     According to another specific feature, the sound signal input unit inputs a digital signal from the audio signal output unit, the acoustic processing unit is constituted by a digital acoustic processing circuit and a DA conversion circuit, and the amp circuit is constituted by an analog circuit which outputs the output of the DA conversion circuit to the cartilage conduction unit as an analog drive signal. In so doing, driving of the cartilage conduction vibration source in a manner suited to cartilage conduction on the basis of ordinary digital sound output can be accomplished at low cost, and with a simple configuration. 
     According to another specific feature, the sound signal input unit inputs a digital signal from the audio signal output unit, the acoustic processing unit is constituted by a digital acoustic processing circuit, and the amp circuit is constituted by an analog circuit which outputs the output of the digital acoustic processing circuit to the cartilage conduction unit as a digital drive signal. In so doing, driving of the cartilage conduction vibration source in a manner suited to cartilage conduction on the basis of ordinary digital sound output can be accomplished by a digital circuit only. 
     According to another specific feature, there is provided a cartilage conduction vibration source device having a vibration source module to which a digital drive signal is input, and in which a low pass filter for the digital drive signal and a piezoelectric bimorph element serving as a cartilage conduction vibration source are integrated. The low pass filter is necessary in cases in which the piezoelectric bimorph element is driven by digital drive signals, but merely by using the aforedescribed vibration source module, driving of the cartilage conduction vibration source in a manner suited to cartilage conduction can be accomplished without the burden entailed by having to make preliminary adjustment of the low-pass filter. 
     According to another specific feature, there is provided a cartilage conduction vibration source device having a sound signal output unit for outputting an analog sound signal, an analog sound signal input unit for inputting an analog sound signal, an analog acoustic processing unit for acoustic processing, for purposes of cartilage conduction vibration, of a sound signal input from the analog sound signal input unit, an analog amplifier unit for outputting an analog processed signal processed by the analog acoustic processing unit, to the cartilage conduction vibration source as a drive signal, and a cartilage conduction vibration source driven by the analog drive signal. In so doing, a suitable cartilage conduction vibration source can be realized through analog circuits. 
     According to another specific feature, there is provided a cartilage conduction vibration source device having a sound signal output unit for outputting an analog sound signal, an analog sound signal input unit for inputting an analog sound signal, an AD conversion circuit for converting a sound signal input from the analog sound signal input unit to a digital signal, a digital acoustic processing unit for acoustic processing, for purposes of cartilage conduction vibration, of the output of the AD conversion circuit, a DA conversion circuit for converting a processed signal processed by the digital acoustic processing unit to an analog signal, an analog amplifier unit for outputting the output of the DA conversion circuit to the cartilage conduction vibration source as an analog drive signal, and a cartilage conduction vibration source driven by the analog drive signal. In so doing, a suitable cartilage conduction vibration source can be realized at controlled cost, on the basis of analog sound output. 
     According to another specific feature, there is provided a cartilage conduction vibration source device having a sound signal output unit for outputting a digital sound signal, a digital sound signal input unit for inputting a digital sound signal, a digital acoustic processing unit for acoustic processing, for purposes of cartilage conduction vibration, of a sound signal input from the digital sound signal input unit, a DA conversion circuit for converting a processed signal processed by the digital acoustic processing unit to an analog signal, an analog amplifier unit for outputting the output of the DA conversion circuit to the cartilage conduction vibration source as an analog drive signal, and a cartilage conduction vibration source driven by the analog drive signal. In so doing, a suitable cartilage conduction vibration source can be realized at controlled cost, on the basis of digital sound output. 
     According to another feature, there is provided a cartilage conduction vibration source device having a sound signal output unit for outputting a digital sound signal, a digital sound signal input unit for inputting a digital sound signal, a digital acoustic processing unit for acoustic processing, for purposes of cartilage conduction vibration, of a sound signal input from the digital sound signal input unit, a digital amplifier unit for outputting a processed signal processed by the digital acoustic processing unit to the cartilage-conduction vibration source as a digital drive signal, a low-pass filter for the digital drive signal, and a cartilage-conduction vibration source driven by a drive signal having passed through the low-pass filter. In so doing, a suitable cartilage conduction vibration source can be realized through digital circuits. In this case, it is possible to integrate the low-pass filter and the cartilage-conduction vibration source and provide these as a vibration source module. 
     [Twenty-Ninth Technical Feature] 
     A twenty-ninth technical feature disclosed in the present specification provides a mobile telephone having a chassis, a cartilage conduction unit differing in acoustic impedance from the chassis and connected to the chassis, a cartilage-conduction vibration source for transmitting vibration to the cartilage conduction unit, and a load connection unit for connecting a load of an internal structure load to the chassis in proximity to the cartilage conduction unit in the chassis. In so doing, vibration of the chassis is suppressed in proximity to the cartilage conduction unit, which corresponds to an entrance section for vibration transmission, and by avoiding connection of the cartilage conduction unit and the chassis at closely approximating acoustic impedance, it is possible to ensure some degree of freedom in vibration of the cartilage conduction unit and obtain satisfactory cartilage conduction. 
     According to a specific feature, the load connection unit connects the load of the internal structure over a small cross-sectional area to the chassis. In so doing, it is possible for the load connection location to be specifically concentrated in proximity to the cartilage conduction unit, which corresponds to an entrance section for vibration transmission, and it is possible to effectively suppress chassis vibration. 
     According to another specific feature, the cartilage conduction unit and the chassis are connected via a vibration isolating material. In so doing, the effect of avoiding connection of the cartilage conduction unit and the chassis at closely approximating acoustic impedance can be enhanced. According to a more specific feature, a section situated away from the load connection unit is furnished with another load connection unit for connecting a load of an internal structure to the chassis. In so doing, the internal structure is reliably held through a simple configuration. 
     According to another specific feature, the cartilage conduction unit and the chassis are connected directly. In so doing, the number of parts is reduced, and the holding structure for the cartilage conduction unit and the chassis is simple. According to a more specific feature, the cartilage conduction unit is configured from an elastic body of greatly different acoustic impedance from the chassis. 
     According to another specific feature, the internal structure is held to the chassis via a lower vibration isolating material, in a section away from the load connection unit. In so doing, it is possible for the internal structure to be held in reliable fashion without diminishing the effect of specifically concentrating the load connection location to one in proximity to the cartilage conduction unit, which corresponds to an entrance section for vibration transmission. 
     According to another specific feature, the load-connected internal structure is a cell. The cell constitutes a large proportion of the load in a mobile telephone, and is moreover a coherent section, and therefore load connection is preferred. According to a more specific feature, the load connection part is furnished to a holder for holding the cell while avoiding a center section thereof. In so doing, it is possible for the load of the cell to be specifically concentrated in suitable fashion at a location in proximity to the cartilage conduction unit. Furthermore, as the center part of the cell swells with the passage of time during use, in order to avoid this, the configuration of the holder is preferably one that avoids the center section. According to another specific feature, it is possible for the internal structure to be a frame structure than includes a cell holding unit. 
     According to another feature, there is provided a mobile telephone having a chassis, a vibration isolating material connected to the chassis, a cartilage conduction unit connected to the chassis via the vibration isolating material, a cartilage-conduction vibration source for transmitting vibration to the cartilage conduction unit, and a load connection unit for connecting a load of an internal structure to the chassis in proximity to the cartilage conduction unit on the chassis. In so doing, vibration of the chassis can be suppressed, without diminishing good cartilage conduction capability, in the manner described previously. 
     In cases in which the cartilage conduction unit connected to the chassis via the vibration isolating material in the aforedescribed manner, it is possible for the chassis and the cartilage conduction unit to be made of materials of equal acoustic impedance. In so doing, the materials for the mobile telephone are more readily procured, and reduction in cost thereof is possible. 
     According to another feature, there is provided a mobile telephone having an internal structure, a cartilage conduction unit connected to the internal structure, a cartilage-conduction vibration source for transmitting vibration to the cartilage conduction unit, and a chassis connected to the internal structure via the vibration isolating material. In so doing, in the first instance, an internal structure constituting most of the load in the mobile telephone is connected to the cartilage conduction unit thus suppressing transmission of vibration, and moreover, the internal structure is connected, via the vibration isolating material, to the chassis which represents a relatively small proportion of the load, thus suppressing vibration of the chassis, which defines the outer surfaces of the mobile telephone. 
     According to a specific feature, the cartilage conduction unit is connected to the internal structure via the vibration isolating material. According to another specific feature, the cartilage conduction unit is an elastic body. According to these features, good cartilage conduction can be ensured, while suppressing vibration of the chassis. 
     [Thirtieth Technical Feature] 
     A thirtieth technical feature disclosed in the present specification provides a cartilage-conduction vibration source device having a sound signal input unit for inputting a sound signal, an acoustic processing unit for variable processing, for purposes of cartilage conduction, of a sound signal input from the sound signal input unit, a control signal input unit for inputting a control signal for purposes of variable processing in the acoustic processing unit, and an amplifier unit for outputting a processed signal processed by the acoustic processing unit to a cartilage-conduction vibration source as a drive signal. In so doing, it is possible to drive the cartilage-conduction vibration source for purposes of cartilage conduction, in an appropriate manner according to changes in conditions. 
     According to a specific feature, the acoustic processing unit modifies acoustic processing in such a way that the drive signal output to the cartilage-conduction vibration source differs in frequency characteristics, according to whether a sound has arrived via a communication unit or the sound has not arrived via the communication unit. In so doing, the cartilage-conduction vibration source can be driven in a manner that increases the contribution of direct air conduction in cartilage conduction for sounds not arriving via the communication unit, relative to sounds arriving via the communication unit. 
     According to another specific feature, the acoustic processing unit modifies acoustic processing in such a way that the drive signal output to the cartilage-conduction vibration source differs in frequency characteristics for a normal individual, versus a person with conductive hearing loss. In so doing, the cartilage-conduction vibration source can be driven in a manner that increases the contribution of cartilage bone conduction in cartilage conduction for a person with conductive hearing loss, relative to a normal individual. 
     According to another specific feature, the acoustic processing unit modifies acoustic processing in such a way that the drive signal output to the cartilage-conduction vibration source differs in frequency characteristics in cases in which the external auditory meatus entrance is unoccluded, versus cases in which the entrance is occluded. In so doing, the cartilage-conduction vibration source can be driven in a manner that halts the contribution of direct air conduction in cartilage conduction in cases in which the external auditory meatus entrance is occluded. 
     According to another specific feature, the acoustic processing unit has a plurality of acoustic processing units, the contributions of the plurality of acoustic processing units to the drive signal being modified on the basis of a control signal. In so doing, acoustic processing optimized for each conduction element of cartilage conduction can be respectively devised, and variable acoustic processing controlled through modification of these contributions. 
     According to a specific feature, there is provided a cartilage-conduction vibration source device having a sound signal input unit for inputting a sound signal, a plurality of acoustic processing units for processing, for purposes of cartilage conduction, of a sound signal input from the sound signal input unit, and an amplifier unit for outputting a processed signal processed by the plurality of acoustic processing units and synthesized, to a cartilage-conduction vibration source as a drive signal. In so doing, acoustic processing can take place through synthesis of acoustic processing optimized for each conduction element of cartilage conduction. 
     According to a specific feature, the plurality of acoustic processing units have a first acoustic processing unit for carrying out acoustic processing on the basis of the frequency characteristics of cartilage bone conduction from the cartilage-conduction vibration source, and a second acoustic processing unit for carrying out acoustic processing on the basis of the frequency characteristics of direct air conduction from the cartilage-conduction vibration source. 
     According to another feature, there is provided a cartilage-conduction vibration source device having a sound signal input unit for inputting a sound signal, an acoustic processing unit for processing, for purposes of cartilage conduction, of a sound signal input from the sound signal input unit, and an amplifier unit for outputting a processed signal processed by the acoustic processing unit to a cartilage-conduction vibration source as a drive signal, the amplifier unit having a gain adjustment unit for adjusting gain according to input signal level, such that the output level is brought to a predetermined drive signal level for the cartilage-conduction vibration source. In so doing, the capabilities of the cartilage-conduction vibration source can be utilized to maximum effect, to achieve appropriate cartilage conduction. 
     According to a specific feature, there is provided a mobile telephone having the aforedescribed cartilage-conduction vibration source device. According to a more specific feature, the mobile telephone is configured as a mobile device having a combination large-screen display unit/touch screen. According to a more specific feature, a cartilage conduction unit is furnished to a distal end of an extendable and retractable holder joined to the mobile telephone body by a universal joint. 
     According to another feature, there is provided a mobile telephone configured as a mobile device, having a combination large-screen display unit/touch screen furnished to the body thereof, and a sound output unit furnished to a distal end of an extendable and retractable holder joined to the body by a universal joint. In so doing, calling is possible through a simple operation while viewing the large screen. According to a specific feature, the sound output unit is a cartilage conduction unit. 
     [Thirty-First Technical Feature] 
     A thirty-first technical feature disclosed in the present specification provides a mobile telephone accessory device having an input unit for an external sound signal output by a mobile telephone, a cartilage conduction unit for vibrating on the basis of an external sound signal input from the input unit, and a support unit for supporting the cartilage conduction unit on the mobile telephone. In so doing, an ordinary mobile telephone can be transformed into a cartilage conduction mobile telephone. 
     According to a specific feature, the holder unit is a soft cover sheathing the mobile telephone, the cartilage conduction unit being situated in an upper corner of the soft cover. In so doing, an ordinary mobile telephone can be transformed into a cartilage conduction mobile telephone by being sheathed with the soft cover. 
     According to a more specific feature, the soft cover is configured to be thicker in an upper portion, a cartilage-conduction vibration source being situated in one corner of the upper section, whereby when the mobile telephone is sheathed in the soft cover, the one corner of the thick section where the cartilage-conduction vibration source is situated is supported as a cartilage conduction unit on the mobile telephone. In so doing, the soft cover can be configured as a suitable mobile telephone accessory device. 
     According to a more specific feature, an external earphone plug for insertion of an external output jack of a mobile telephone is situated as an input unit, within the other corner of the thick section of the soft cover. In so doing, there can be configured a mobile telephone accessory device that suitably utilizes the external output of an ordinary mobile telephone. 
     According to a more specific feature, the external earphone plug is situated in the other corner of the thick section where the external output jack of the mobile telephone is insertable prior to sheathing the mobile telephone in the soft cover. In so doing, the mobile telephone can be sheathed by the soft cover, while easily making connection to an external output from the mobile telephone. 
     According to another more specific feature, the soft cover has a drive unit for driving the cartilage-conduction vibration source, on the basis of a sound signal input from the input unit. In so doing, the cartilage-conduction vibration source can be driven in a suitable manner, on the basis of an external output from the mobile telephone. According to more specific feature, the soft cover has a power supply unit for supplying power to the drive unit. Suitable cartilage conduction on the basis of an external output from the mobile telephone can be accomplished thereby. 
     According to another more specific feature, the cartilage-conduction vibration source is an electromagnetic vibrator. In doing, there can be obtained a cartilage-conduction vibration source that is easily assembled into the soft cover. 
     According to another feature, there is provided a mobile telephone having a cartilage conduction vibration unit situated in one upper corner sandwiched between a front face and a rear face, and capable of transmitting vibration from the front face side to the rear face side, and a microphone having symmetrical directionality with respect to the front face side and the rear face side. In so doing, it is possible to make calls in in suitable fashion, with the single cartilage conduction vibration unit placed against either the right ear or the left ear. 
     According to a specific feature, the microphone is situated on a side face between the front face and the rear face. According to another specific feature, the microphone is situated on a bottom face between the front face and the rear face. These features respectively facilitate placement of a microphone having symmetrical directionality with respect to the front face side and the rear face side. 
     According to another specific feature, the microphone is furnished to a lower corner which is situated in proximity to the side directly below the upper corner furnished with the cartilage conduction vibration unit. In so doing, the microphone can pick up sound in proximity to mouth, both in the case of placing the single cartilage conduction vibration unit against the right ear, and the case of placing it against the left ear. 
     (Thirty-Second Technical Feature) 
     A thirty-second technical feature disclosed in the present specification provides a mobile telephone having a sound signal source unit for outputting a sound signal, an equalizer for applying correction to a sound signal output from the sound signal source unit, doing so on the basis of the vibration frequency characteristics of ear cartilage, and a cartilage-conduction vibration source vibrated by the sound signal corrected by the equalizer. In so doing, there can be provided a cartilage conduction mobile telephone incorporating a medical aspect relating to vibration transmission in ear cartilage. 
     According to a specific feature, the equalizer performs correction to boost the gain at the high end within the frequency band at which the cartilage-conduction vibration source is vibrated. This configuration incorporates the medical knowledge that, in the frequency characteristics of vibration transmission in ear cartilage, vibrational acceleration is low at the high end within the frequency band at which the cartilage-conduction vibration source is vibrated. 
     According to a more specific feature, with the external auditory meatus in the occluded state, the equalizer performs correction to boost the gain at the high end within the frequency band at which the cartilage-conduction vibration source is vibrated, to a level higher than the gain when the external auditory meatus is in the unoccluded state. This configuration is based on the medical knowledge that, during cartilage conduction with the external auditory meatus in the unoccluded state, the direct air conduction component is quite large at the high end within the frequency band at which the cartilage-conduction vibration source is vibrated. The configuration moreover takes into account the fact that this direct air conduction component disappears with the external auditory meatus in the occluded state. 
     According to a more specific feature, the mobile telephone has a detection unit for detecting pressing of the mobile telephone against the ear cartilage, and when the output of the detection unit is at or above a predetermined level, the equalizer performs correction to boost the gain at the high end within the frequency band at which the cartilage-conduction vibration source is vibrated, to a level higher than the gain when the external auditory meatus is in the unoccluded state. In so doing, equalization switching can take place in suitable fashion. 
     According to another more specific feature, the mobile telephone has a detection unit for detecting environment noise, and when the output of the detection unit is above a predetermined level, the equalizer performs correction to boost the gain at the high end within the frequency band at which the cartilage-conduction vibration source is vibrated, to a level higher than the gain when the external auditory meatus is in the unoccluded state. This configuration is designed so that equalization switching takes place on the assumption that, when environment noise is above a predetermined level, the user will press the mobile telephone against the ear cartilage to the extent that the external auditory meatus entrance is occluded. 
     According to a more specific feature, the equalizer performs correction to boost the gain at the high end within the frequency band at which the cartilage-conduction vibration source is vibrated, to a level higher than the gain when the external auditory meatus is in the unoccluded state, doing so on the basis of a moving average output of a detection unit. In so doing, equalization switching can takes place in a smooth manner while preventing misoperation. 
     According to a more specific feature, when determined on the basis of the output of the detection unit that the external auditory meatus is obstructed, the equalizer performs correction to rapidly boost the gain at the high end within the frequency band at which the cartilage-conduction vibration source is vibrated, to a level higher than the gain when the external auditory meatus is in the unoccluded state; while halting correction to boost the gain, when output changes of the detection unit have been ascertained multiple times during a decision that the external auditory meatus is unoccluded. This configuration is designed to perform equalization rapidly when the external auditory meatus is occluded, due to the fact that under this condition sounds audible through the external auditory meatus occlusion effect are louder, and changes in sound quality tend to be more noticeable; as well as to prevent excessive equalization switching due to misoperation when the external auditory meatus is unoccluded. 
     According to another specific feature, the mobile telephone has an external sound output unit or a short-range wireless communication unit, and the equalizer performs correction to boost the gain at the high end within the frequency band at which the cartilage-conduction vibration source is vibrated, to a level higher than the gain in sound output from these external output means. This configuration uses equalization appropriate to ordinary air conduction as a benchmark, but incorporates a medical aspect relating to the frequency characteristics of vibration transmission in ear cartilage. 
     According to another specific feature, there is provided a mobile telephone accessory device having an input unit for input of a sound signal output from a mobile telephone, an equalizer for applying correction to a sound signal from the input unit, doing so on the basis of vibration transmission frequency characteristics of ear cartilage, and a cartilage-conduction vibration source vibrated by the sound signal corrected by the equalizer. In so doing, there can be provided an accessory device for a mobile telephone, in which sound output that uses equalization appropriate to ordinary air conduction as a benchmark is input from the mobile telephone, and on the basis thereof, cartilage conduction incorporating a medical aspect relating to vibration transmission in ear cartilage is achieved. 
     According to a specific feature, the equalizer performs correction to boost the gain at the high end within the frequency band at which the cartilage-conduction vibration source is vibrated. Input of sound signals from the mobile telephone to the accessory device may be carried out through a wired connection, or through wireless short-range communication means such as short-range wireless or infrared communication. 
     (Thirty-Third Technical Feature) 
     A thirty-third technical feature disclosed in the present specification provides a mobile telephone in which elastic bodies are interposed between an upper edge part of the mobile telephone including both upper corners, and other sections of the mobile telephone, and a cartilage-conduction vibration source is furnished inside the upper edge part, such that there is substantially no contact thereof with other sections of the mobile telephone. In so doing, the upper edge of the mobile telephone including both upper corners of the mobile telephone can be vibrated efficiently. 
     According to a specific feature, the cartilage-conduction vibration source is furnished to the inside center of the upper edge part. In so doing, both upper corners of the mobile telephone can be vibrated efficiently, and an upper edge center part can be vibrated efficiently as well. 
     According to another specific feature, the upper edge part is an upper frame of the mobile telephone. In so doing, the upper edge of the mobile telephone including both upper corners of the mobile telephone can be vibrated efficiently, in a manner consistent with the configuration of the mobile telephone. According to a more specific feature, a front face panel of the mobile telephone contacts the upper frame of the mobile telephone. In so doing, suitable cartilage conduction from a front face upper part of the mobile telephone may be obtained in a manner consistent with the configuration of the mobile telephone. 
     According to a more specific feature, the mobile telephone is furnished with two side frames situated with elastic bodies interposed in relation to the upper frame, and contacting the front face panel. In so doing, vibration of the lower front face panel is effectively suppressed. 
     According to a more specific feature, a section of the front face panel contacting the upper frame is at least partially thinner than sections contacting the two side frames. In so doing, vibration of the lower front face panel is effectively suppressed. 
     According to another specific feature, the upper edge part gives rise to cartilage conduction through ear cartilage, when either of the two upper corners is placed in contact with the ear cartilage. In so doing, it is possible take advantage of cartilage conduction when using the mobile telephone. 
     According to another specific feature, the upper edge part gives rise to cartilage conduction through ear cartilage when a center part thereof is placed in contact with the ear cartilage. In so doing, cartilage conduction may be obtained during use as an ordinary mobile telephone. 
     According to another specific feature, the upper edge part is configured to produce predetermined air-conducted sound. In so doing, the air-conducted sound required of an ordinary mobile telephone can be obtained, without furnishing an ordinary speaker. 
     According to another specific feature, the upper edge part is furnished with an external earphone jack which vibrates together with the upper edge part. According to a more specific feature, when detected that an external earphone plug has been inserted into the external earphone jack, vibration of the cartilage-conduction vibration source is prohibited. According to another specific feature, an in-camera is situated in proximity to the upper edge part, and when a mode for using the in-camera is detected, vibration of the cartilage-conduction vibration source is prohibited. According to another specific feature, the upper edge part is furnished with a window through which a power switch can move up or down without contacting the upper edge part. 
     According to another feature, there is provided a mobile telephone having an antenna, and a cartilage-conduction vibration source furnished to the antenna, for concomitantly employing the antenna as a cartilage conduction unit. In so doing, suitable cartilage conduction can be obtained from a front face upper part of the mobile telephone in a manner consistent with the configuration of the mobile telephone. 
     (Thirty-Fourth Technical Feature) 
     A thirty-fourth technical feature disclosed in the present specification provides a listening device having a cartilage conduction unit for contacting the outside of the base of the ear, and a cartilage-conduction vibration source for propagation of vibration to the cartilage conduction unit. In so doing, the external auditory meatus entrance region is completely free, and so entry of sounds, such as a car horn, into the ear in an emergency situation is unimpeded, nor is there the discomfort associated with inserting an earphone or the like into the external auditory meatus entrance. An external auditory meatus occluding effect can readily be obtained, for example, by covering the ear with the hand in order to enhance the cartilage conduction effect, whereby increased volume and blockage of outside noise can be achieved. 
     According to a specific feature, the listening device provided with the aforedescribed features has an ear-hook unit for linear contact while hooked around the outside of the base of the ear, the inner edge of the ear-hook unit functioning as the cartilage conduction unit. In so doing, suitable holding of the cartilage conduction unit, and satisfactory cartilage conduction, can be achieved. 
     According to a more specific feature, the ear-hook unit is configured of elastic material having acoustic impedance close to that of ear cartilage. In so doing, satisfactory cartilage conduction and a comfortable fit to the outside of the base of the ear can be achieved. 
     According to another specific feature, the cartilage-conduction vibration source is situated in proximity to a section closest to the external auditory meatus entrance, at the outside of the cartilage of the base of ear. In so doing, vibration of the cartilage-conduction vibration source can generate air-conducted sound from the external auditory meatus inner wall through the agency of the cartilage surrounding the external auditory meatus opening, which is then transmitted to the eardrum. 
     According to a more specific feature, a piezoelectric bimorph element is employed as the cartilage-conduction vibration source, adopting a configuration in which one end of the piezoelectric bimorph element is supported by the cartilage conduction unit in proximity to a section closest to the external auditory meatus entrance, at the outside of the cartilage of the base of ear, and the other end side of the piezoelectric bimorph element does not contact the cartilage conduction unit. According to a more specific feature, an electromagnetic vibrator is employed as the cartilage-conduction vibration source, the electromagnetic vibrator being situated in proximity to a section closest to the external auditory meatus entrance, at the outside of the cartilage of the base of ear. 
     According to another more specific feature, the device has a microphone, and a vibration transmission prevention means is devised between the microphone and the cartilage conduction unit contacting the outside of the base of the ear. In so doing, the effects of vibration of the cartilage conduction unit on the microphone can be reduced, in cases in which the listening device of the present invention is applied to an outgoing-talk/incoming-talk device for the purpose of making calls. 
     According to another more specific feature, the vibration transmission prevention means involves configuring the microphone, a power supply unit, and a short-range communication unit for communication with the mobile telephone as separate body from the cartilage conduction unit, the cartilage-conduction vibration source of the cartilage conduction unit and the separate body being connected by flexible cable. According to another more specific feature, a microphone, a power supply unit having a cell, a short-range communication unit for communication with the mobile telephone, and the cartilage conduction unit are configured as an integrated body, the vibration transmission prevention means being realized by situating the cell between the microphone and the cartilage conduction unit in order to suppress vibration due to the load of the cell. 
     According to another feature, there is provided a listening device having a cartilage conduction unit having a passage hole at the center, for insertion into the external auditory meatus entrance, a shutter for opening and closing the passage hole, and a shutter drive unit for driving opening and closing of the shutter by a signal from the outside. In so doing, appropriate external auditory meatus occluding effect can be obtained automatically, or by a manual operation, without the need to push the cartilage conduction unit or block the ear with the hand. 
     According to a specific feature, the listening device has a parameter detection unit, and the shutter drive unit drives opening or closing of the shutter through a signal from the parameter detection unit. The parameter detection unit, for example, detects outside noise, and when the outside noise is above a predetermined level, generates a signal to occlude the shutter, or when the outside noise is below a predetermined level, generates a signal to unocclude the shutter. According to another specific feature, the listening device has a manually-operated unit, and the shutter drive unit drives opening or closing of the shutter through an operation signal generated by operation of the manually-operated unit. 
     According to another feature, there is provided a listening device having an external auditory meatus insertion unit having a passage hole at the center, for insertion into the external auditory meatus entrance, a shutter for opening and closing the passage hole, and a shutter drive unit for driving opening and closing of the shutter by a signal from the outside. In so doing, appropriate external auditory meatus occluding effect can be obtained automatically, or by a manual operation, without the need to push the cartilage conduction unit or block the ear with the hand. 
     (Thirty-Fifth Technical Feature) 
     A thirty-fifth technical feature disclosed in the present specification provides an outgoing-talk/incoming-talk device having a cartilage conduction unit for contacting the mastoid side of the region of attachment of the auricle, and a contact microphone. In so doing, the outgoing-talk/incoming-talk device can be worn compactly on the head, making it possible, for example, for a helmet or the like to be worn from above. 
     According to a specific feature, the outgoing-talk/incoming-talk device has a cell, the contact microphone being isolated from the cartilage conduction unit by the cell. In so doing, propagation of vibration of the cartilage conduction unit to the contact microphone is suppressed by the cell, making it possible for the contact microphone to be used in suitable fashion. According to another specific feature, the outgoing-talk/incoming-talk device is furnished with canceling means for canceling vibration of the cartilage conduction unit picked up by the contact microphone. In so doing, it is possible for the contact microphone to be used in suitable fashion. 
     According to another specific feature, the contact microphone is furnished in proximity to the cartilage conduction unit. In so doing, the outgoing-talk/incoming-talk device can be accommodated compactly in a space behind the ear, making it possible, for example, for a helmet or the like to be worn from above. 
     According to a more specific feature, the contact microphone is situated contacting an area in proximity to the mastoid. According to another more specific feature, the contact microphone is situated contacting an area in proximity to the lower jaw. According to another more specific feature, the contact microphone is situated contacting an area in proximity to the mastoid side of a sternomastoid muscle. With each of these features, suitable voice pickup of can be achieved with the contact microphone in a compact arrangement in proximity to the cartilage conduction unit. 
     According to another specific feature, the device has a wireless communication capable of wireless communication with external equipment. In so doing, the outgoing-talk/incoming-talk device can be given a compact configuration, making it possible, for example, for a helmet or the like to be worn from above. 
     According to another specific feature, cartilage conduction units are furnished so as to respectively contact the mastoid side of the region of attachment of the auricle in each ear. In so doing, stereo listening becomes possible, and the constituent elements of the outgoing-talk/incoming-talk device can be apportioned among both ears, enhancing compactness of the device. 
     According to a more specific feature, the outgoing-talk/incoming-talk device is furnished with a support unit for supporting cartilage conduction units which are furnished for both ears and linked thereto. According to a more specific feature, the contact microphone is furnished to the support unit. According to a specific feature, the contact microphone is situated so as to pick up vibration of the sternomastoid muscle. 
     According to another specific feature, the contact microphone is furnished asymmetrically with respect to cartilage conduction units furnished for both ears, and mutually different canceling is performed on the respective vibrations of the cartilage conduction units picked up by the contact microphone. 
     According to another specific feature, cells are respectively situated in proximity to cartilage conduction units furnished for both ears. In so doing, there can be realized an outgoing-talk/incoming-talk device in which the cells, which occupy considerable volume, are situated in a compact arrangement, making it possible, for example, for a helmet or the like to be worn from above. 
     According to another feature, there is furnished an outgoing-talk/incoming-talk device having a cartilage conduction unit for contacting the mastoid side of the region of attachment of the auricle, and a cover unit for covering an area in proximity to the external auditory meatus entrance. In so doing, sounds obtained through cartilage conduction unit can be heard at higher volume. According to a specific feature, the cover unit is a helmet. 
     &lt;Thirty-Sixth Technical Feature&gt; 
     A thirty-sixth technical feature disclosed in the present specification provides a mobile telephone having a touch panel/large-screen display unit, an external earphone jack, and a controller for disabling the touch panel functions of the touch panel/large-screen display unit when call-related functions are in operation, excluding videoconferencing when the external earphone jack is in use. It is thereby possible to prevent accidental operation of the touch panel also when the external earphone jack is being used. 
     According to a specific feature, the controller disables the touch panel functions of the touch panel/large-screen display unit on the basis of an incoming call response operation. It is thereby possible to implement both required operation of the touch panel and prevent of accidental operation. According to a more specific feature, the controller disables the touch panel functions of the touch panel/large-screen display unit after a predetermined time from the incoming call response operation. It is thereby possible to disable the touch panel functions suitable to a passive operation such as an incoming call response. 
     According to a more specific feature, the controller disables the touch panel functions of the touch panel/large-screen display unit on the basis of a call start. It is thereby possible to implement both operation required by the touch panel and prevent accidental operation. 
     According to a more specific feature, the controller disables the touch panel functions of the touch panel/large-screen display unit on the basis of an incoming call response operation or a call start, and has a different process for disabling in accordance with which action the disabling is based. 
     In accordance with another specific feature, the controller enables the touch panel functions of the touch panel/large-screen display unit on the basis of a call cutoff operation using other than the touch panel. It is thereby possible to implement both operation using the touch panel as well as prevention of accidental operation. 
     In accordance with another specific feature, the controller disables the touch panel functions of the touch panel/large-screen display unit when call-related functions, excluding videoconferencing, are operating in a state in which the external earphone jack is not being used. It is thereby possible to implement both required operation using the touch panel as well as prevention of accidental operation, regardless of the existence of use of the external earphone jack. 
     In accordance with a more specific feature, the controller disables the touch panel functions of the touch panel/large-screen display unit when call-related functions, excluding videoconferencing, are operating, by using means that differs between when the external earphone jack is being used and not being used. It is thereby possible to perform control suitable for use and non-use of the earphone jack. 
     In accordance with another specific feature, the controller disables the touch panel functions of the touch panel/large-screen display unit when call-related functions, excluding videoconferencing, are operating, by using shared means when the external earphone jack is being used and not being used. It is thereby possible to implement both required operation using the touch panel as well as prevention of accidental operation using a simple configuration. 
     In accordance with another specific feature, the shared means disables the touch panel functions of the touch panel/large-screen display unit on the basis of an incoming call response operation or a call start, and enables the touch panel functions of the touch panel/large-screen display unit on the basis of a call cutoff operation other than by the touch panel. 
     In yet another specific feature, the shared means is a proximity sensor and disables the touch panel functions of the touch panel/large-screen display unit on the basis of detection of proximity to the ear by the proximity sensor. 
     &lt;Thirty-Seventh Technical Feature&gt; 
     A thirty-seventh technical feature disclosed in the present specification provides a mobile telephone having a cartilage conduction unit, a power supply switch, and a description unit for describing the method for using the cartilage conduction function, the description lasting for a predetermined time starting from when the power supply switch is turned on. A user who is unaware of the cartilage conduction function can thereby use the function without confusion. 
     In accordance with another feature, there is a provided a mobile telephone having a cartilage conduction unit, a call operation unit, and a description unit for starting a description of the method for using the cartilage conduction function when the call operation unit has been operated. A user who is unaware of the cartilage conduction function can thereby use the function without confusion. In accordance with a specific feature, the description unit stops description when another party has responded to a call. 
     In accordance with another feature, there is provided a mobile telephone having a cartilage conduction unit, and a description unit for starting a description of the method for using the cartilage conduction function when there is an incoming call. A user who is unaware of the cartilage conduction function can thereby use the function without confusion. In accordance with a specific feature, the mobile telephone has an incoming call response operation unit, and the description unit stops description when the incoming call response operation unit has been operated. 
     In accordance with the specific features above, the mobile telephone has a stop operation unit capable of arbitrarily stopping the description by the description unit. In accordance with a more specific feature, the description unit does not provide description after the stop operation unit has been operated. 
     In accordance with another specific feature, the mobile telephone has a normal-usage detection unit for detecting that the cartilage conduction function is being used correctly, and the description unit stops description when the normal-usage detection unit has detected correct usage. In accordance with a more specific feature, the description unit does not provide description after the normal-usage detection unit has detected correct usage. 
     In accordance with another specific feature, the mobile telephone has a display unit, and the description unit displays the description on the display unit. 
     In accordance with another specific feature, the mobile telephone has a proximity sensing unit, and the description unit outputs a description announcement from the cartilage conduction unit which the proximity sensing unit detects the mobile telephone to be proximate to the ear. 
     In accordance with another specific feature, the mobile telephone has a tilt detection unit, and the description unit provides a description for right-hand use at a first tilt and for left-hand use at a second tilt. 
     In accordance with another feature, there is provided a listening device having a sound source device having a maximum output to the exterior of 500 mVrms or more, and a pair of cartilage conduction units for use with both ears that achieves a vibration acceleration of 50 dB (reference value=10 −6  m/sec 2 ) or more to the rear surface side of the tragus when there is input of 200 mVrms by connection to an external output of the sound source device, wherein the cartilage conduction units are each provided with a passage hole for introducing air-conducted sound from the exterior to the entrance to the external auditory meatus. 
     In accordance with a specific feature, the sound source device has a controller for responding to an incoming call to an external mobile telephone and stopping output to the pair of cartilage conduction units. 
     &lt;Thirty-Eighth Technical Feature&gt; 
     A thirty-eighth technical feature disclosed in the present specification provides a cartilage conduction vibration source device having a sound signal input unit for inputting a sound signal, an acoustic processing unit for acoustic processing, for purposes of cartilage conduction vibration, of the sound signal input from the sound signal input unit, a power source input unit, a voltage booster circuit unit for boosting an input voltage to the power source input unit, and an amplifier unit for outputting a processed signal processed by the acoustic processing unit to the cartilage conduction vibration source as a drive signal, the amplifier unit being supplied with power by the voltage booster circuit unit. It is thereby possible for an advantageous cartilage conduction vibration source to be readily driven in a manner suited to cartilage conduction, by input of an ordinary sound signal and driving by an ordinary power source. In accordance with a specific feature, the sound signal input unit receives input of an analog signal from the sound signal output unit; the acoustic processing unit and the amplifier unit are composed of an analog circuit, and the analog drive signal is outputted to a cartilage conduction vibration source. The cartilage conduction vibration source can thereby be readily and advantageously driven for cartilage conduction based on sound output for an ordinary speaker. In accordance with another specific feature, the sound signal input unit receives input of an analog signal from the sound signal output unit; the acoustic processing unit is composed of an AD conversion circuit, a digital acoustic processing circuit, and a DA conversion circuit; and the amplifier circuit is composed of an analog circuit and outputs the output of the DA conversion circuit to the cartilage conduction vibration source as an analog drive signal. The cartilage conduction vibration source can thereby advantageously driven at low cost for cartilage conduction based on sound output for an ordinary speaker. In accordance with another specific feature, the sound signal input unit receives input of a digital signal from the sound signal output unit; the acoustic processing unit is composed of a digital acoustic processing circuit; and the amplifier circuit is composed of a digital circuit and outputs the output of the digital acoustic processing circuit to the cartilage conduction vibration source as a digital drive signal. The cartilage conduction vibration source can thereby advantageously driven using only a digital circuit for cartilage conduction based on ordinary digital sound output. In accordance with another specific feature, an amplifier unit and a switching generator in the form of an IC are used as the voltage booster circuit. 
     In accordance with another feature, there is provided a cartilage conduction vibration source device for receiving input of a digital drive signal, and having a vibration source module integrally composed of a low-pass filter for the drive signal and a piezoelectric bimorph element serving as a cartilage conduction vibration source. A low-pass filter is required when the piezoelectric bimorph element is driven using a digital drive signal, but it is possible to drive a cartilage conduction vibration source suitable for cartilage conduction without the burden of preparing and adjusting a low-pass filter by merely using the above-described vibration source module. 
     In accordance with another feature, there is provided a cartilage conduction vibration source device having: an audio signal output unit for outputting an analog audio signal; an analog audio signal input unit for receiving input of an analog audio signal; an analog acoustic processing unit for acoustic processing of audio signals inputted from the analog audio signal input unit to produce cartilage conduction vibrations; an analog amplifier unit for outputting the analog processing signal processed in the analog acoustic processing unit to the cartilage conduction vibration source as a drive signal; and a cartilage conduction vibration source driven by the analog drive signal. An advantageous cartilage conduction vibration source is thereby implemented by an analog circuit. 
     In accordance with another feature, there is provided a cartilage conduction vibration source device having: an audio signal output unit for outputting an analog audio signal; an analog audio signal input unit for receiving input of an analog audio signal; an AD conversion circuit for converting an audio signal inputted from the analog audio signal input unit into a digital signal; a digital acoustic processing unit for acoustic processing of the output of the AD conversion circuit to produce cartilage conduction vibrations; a DA conversion circuit for converting processed signals processed by the digital acoustic processing unit into an analog signal; an analog amplifier unit for outputting the output of the DA conversion circuit to the cartilage conduction vibration source as a drive signal; and a cartilage conduction vibration source driven by the analog drive signal. An advantageous cartilage conduction vibration source is thereby implemented as lower cost on the basis of analog audio output. 
     In accordance with another feature, there is provided a cartilage conduction vibration source device having: an audio signal output unit for outputting a digital audio signal; a digital audio signal input unit for receiving input of a digital audio signal; a digital acoustic processing unit for acoustic processing of an audio signal inputted from the digital audio signal input unit to produce cartilage conduction vibrations; a DA conversion circuit for converting processed signals processed by the digital acoustic processing unit into an analog signal; an analog amplifier unit for outputting the output of the DA conversion circuit to the cartilage conduction vibration source as a drive signal; and a cartilage conduction vibration source driven by the analog drive signal. An advantageous cartilage conduction vibration source is thereby implemented as lower cost on the basis of digital audio output. 
     In accordance with another feature, there is provided a cartilage conduction vibration source device having: an audio signal output unit for outputting a digital audio signal; a digital audio signal input unit for receiving input of a digital audio signal; a digital acoustic processing unit for acoustic processing of an audio signal inputted from the digital audio signal input unit to produce cartilage conduction vibrations; a digital amplifier unit for outputting processed signals processed by the digital acoustic processing unit to the cartilage conduction vibration source as digital drive signals; a low-pass filter for digital drive signals; and a cartilage conduction vibration source driven by the drive signals that have passed through the low-pass filter. An advantageous cartilage conduction vibration source is thereby implemented by a digital circuit. In this case, the low-pass filter and the cartilage conduction vibration source can be integrated together and provided as a vibration source module. 
     In accordance with another feature, there is provided a listening device having: a cartilage conduction vibration source for vibrating in a direction that crosses the center axis of the entrance of the external auditory meatus; and a cartilage conduction unit for transmitting the vibrations of a cartilage conduction vibration source to ear cartilage. It is thereby possible to generate cartilage-air conduction with good efficiency in the external auditory meatus. In accordance with another specific feature, the configuration described above is useful when the configuration is such that the cartilage conduction unit makes contact with the mastoid process side of the auricle attachment region. In accordance with another specific feature, the configuration described above is useful when the configuration is such that the cartilage conduction unit is in contact with the front side of the tragus. 
     In accordance with another feature, there is provided a listening device having: an ear-wearing structure for sandwiching the ear with a first cartilage conduction unit that makes contact with the mastoid process side of the auricle attachment region and a second cartilage conduction unit for making contact with the front side of the tragus; and a cartilage conduction vibration source for transmitting vibrations to the first and second cartilage conduction unit. Stable wearing of the listening device on the ear is thereby ensured by contact of the first and second cartilage conduction units for good cartilage conduction. In accordance with a specific feature, the wearing structure has a linking part for transmitting vibrations between the first cartilage conduction unit and the second cartilage conduction unit. Vibration transmission to the first and second cartilage conduction units is thereby possible even using a single cartilage conduction vibration source. In accordance with another specific feature, the cartilage conduction vibration source for transmitting vibrations to the first and second cartilage conduction units vibrates in a direction crosswise to the center axis of the entrance to the external auditory meatus. 
     In accordance with another specific feature, the wearing structure is configured so that the distance between first cartilage conduction unit and the second cartilage conduction unit is variable. It is thereby possible to achieve advantageous contact with ear cartilage without dependency on personal differences. In accordance with a further specific feature, the wearing structure has a spring property for bringing the second cartilage conduction unit closer to the first cartilage conduction unit. 
     In accordance with a further specific feature, a stereo listening device having a pair of the listening devices as described above for the left and right ears, wherein the wearing structure in each of the pair of listening devices has an adjustment unit for adjusting the strength of the spring property, and visible display unit for achieving balance in the spring property of the pair of listening devices. It is thereby possible to adjust, in a simple manner, the balance of the stereo listening device adapted to personal differences. 
     &lt;Thirty-Ninth Technical Feature&gt; 
     A thirty-ninth technical feature disclosed in the present specification provides a mobile telephone having a cartilage conduction unit and a cartilage conduction vibration source set in each corner of the upper part of the mobile telephone, and the two ends of the cartilage conduction vibration source are supported by the cartilage conduction unit so that the center part of the cartilage conduction vibration source is between the front surface and the back surface and arranged near one or the other surface without being in contact with either surface. Vibrations of the cartilage conduction vibration source are thereby transmitted with good efficiency to the cartilage conduction unit, the amount of space that the center part of the cartilage conduction vibration source occupies between the front surface and the back surface of the mobile telephone is reduced, and arrangement of other components in the upper part of the mobile telephone is facilitated. 
     In accordance with a specific feature, the center part of the cartilage conduction vibration source is bent from both ends so as to be near the front surface or the back surface of the mobile telephone. It is thereby possible bring the center part of the cartilage conduction vibration source near to the front surface or the back surface while comfortably supporting both ends of the cartilage conduction unit. 
     In accordance with another specific feature, the direction of vibration of the cartilage conduction vibration source is the direction crosswise to the front surface and back surface of the mobile telephone. Satisfactory cartilage conduction can thereby be achieved in the cartilage conduction unit, and the amount of space that the center part of the cartilage conduction vibration source occupies between the front surface and the back surface of the mobile telephone is readily reduced. In accordance with a more specific feature, the cartilage conduction vibration source has a metal plate supported at two ends substantially parallel to the front surface and back surface of the mobile telephone by the cartilage conduction unit, and a piezoelectric ceramic disposed on both sides of the metal plate. It is thereby possible to implement a vibration direction of the cartilage conduction vibration source that is crosswise to the front surface and back surface of the mobile telephone. 
     In accordance with a further specific feature, a piezoelectric ceramic is not provided to the two end parts of the metal plate, and the two end parts are bent. It is thereby possible to bring the center part of the cartilage conduction vibration source provided with a piezoelectric ceramic near to the front surface and back surface of the mobile telephone while comfortably supporting the two ends of the metal plate. 
     In accordance with another specific feature, a circuit for driving the piezoelectric ceramic is disposed on the metal plate. In accordance with a further specific feature, a circuit for driving the piezoelectric ceramic is disposed on the inner side of the bend of the metal plate. Mounting of the cartilage conduction vibration source circuit can thereby be facilitated. In a more specific feature, the circuit has a voltage booster circuit, an amplifier, a pair of power source terminals, and a pair of drive signal input terminals. 
     In accordance with another specific feature, a center part of the cartilage conduction vibration source is arranged near the front surface of the mobile telephone, and an air-conducted sound transit part for allowing passage of air-conducted sound generated by the cartilage conduction vibration source is provided to the front surface of the mobile telephone. It is thereby possible to hear sound mainly produced by air-conducted sound to carry out a mobile telephone call by bringing the center of the upper part of the mobile telephone to the ear. 
     In accordance with another feature, there is provided as cartilage conduction vibration source device characterized in having a metal plate, and a piezoelectric ceramic arranged on both sides of the metal plate leaving both ends of the metal plate, the two ends of the metal plate being bent. When such a cartilage conduction vibration source device is mounted in a mobile telephone, the center part of the cartilage conduction vibration source provided with the piezoelectric ceramic can be brought close to the obverse surface or the reverse surface of the mobile telephone while comfortably supporting the two ends of the metal plate. In accordance with a more specific feature, a circuit for driving the piezoelectric ceramic is provided to the inner side of the bending on the metal plate. In accordance with a further specific feature, the circuit has a voltage booster circuit, an amplifier, a pair of power source terminals, and a pair of drive signal input terminals. 
     In accordance with another feature, there is provided a cartilage conduction vibration source device having a cartilage conduction vibration source, a circuit for driving the cartilage conduction vibration source, a pair of power source terminals, and a pair of drive signal input terminals, these being integrally modularized. Good cartilage conduction can be implemented without adding other circuitry. In accordance with a more specific feature, the circuit includes an acoustic processing circuit, a voltage booster circuit, and an amplifier. Cartilage conduction vibration with consideration given to the characteristics of cartilage conduction can thereby be implemented without adding other circuitry. 
     In accordance with another feature, there is provided a cartilage conduction vibration source device having a metal plate, and a piezoelectric ceramic arranged on both sides of the metal plate leaving both ends of the metal plate, the two ends of the metal plate having surplus length. A shared cartilage conduction vibration source device can thereby be mounted in various mobile telephones. In accordance with a specific feature, the surplus length is used for bending the two ends of the metal plate. In accordance with another specific feature, the surplus length is used for cutting the two ends of the metal plate. 
     In accordance with another feature, there is provided a cartilage conduction vibration source device having a metal plate, and a piezoelectric ceramic arranged on both sides of the metal plate leaving both ends of the metal plate, the piezoelectric ceramic having the same structure as another cartilage conduction vibration source, and the two ends of the metal plate being different from another cartilage conduction vibration source. In accordance with such a configuration, the piezoelectric ceramic portion is shared to make mass production possible, and the two end portions of the metal plate can be readily customized for mounting in various mobile telephones. In accordance with a specific feature, the two ends of the metal plate are bent so as to be different from another cartilage conduction vibration source. In accordance with another specific feature, the two ends of the metal plate have different lengths from another cartilage conduction vibration source. 
     &lt;Fortieth Technical Feature&gt; 
     The fortieth technical feature disclosed in the present specification, there is provided a mobile telephone having: a cartilage conduction unit set in each corner of the upper part of the mobile telephone; a piezoelectric bimorph element serving as a vibration source of the cartilage conduction unit; an analog output amplifier for outputting audio signals to the piezoelectric bimorph element; and backflow prevention means for preventing voltaic power produced by an impact to the piezoelectric bimorph element to the analog output amplifier, the backflow prevention means being disposed between the analog output amplifier and the piezoelectric bimorph element. The corners of the mobile telephone are used as cartilage conduction units, the corners being advantageous for abutting against the tragus and other ear cartilage and are locations which are prone to receiving direct impact when dropped, and in the case that the piezoelectric bimorph element is used as the vibration source thereof, it is thereby possible to prevent the analog output amplifier from being broken by an impact pulse produced by the piezoelectric bimorph element due to drop impact or the like. 
     In accordance with a specific feature, the backflow prevention means has a filter for allowing the audio signal band to pass and cutting a band produced by an impact to the piezoelectric bimorph element. An RC filter, an LC filter, or the like is advantageous as such a filter. 
     In accordance with a more specific feature, the filter is a low-pass filter that cuts a frequency band at or higher than the audio signal band. In accordance with a further specific feature, the low-pass filter cuts a frequency band of 8 kHz or higher. In accordance with a further specific feature, the low-pass filter cuts a frequency band of 4 kHz or higher. 
     In accordance with another specific feature, the mobile telephone has a tap detection unit for detecting an impact to the piezoelectric bimorph element due to a finger tap, and the backflow prevention means allows passage of impacts to the piezoelectric bimorph element due to a finger tap. 
     In accordance with a further specific feature, the backflow prevention means has a filter for allowing passage of an audio signal band and an impact to the piezoelectric bimorph element due to a finger tap and cutting a band produced by an impact to the piezoelectric bimorph element. 
     In accordance with a more specific feature, the filter is a low-pass filter that cuts a frequency band at or above the audio signal band and a band produced by an impact to the piezoelectric bimorph element due to a finger tap. 
     In accordance with a further specific feature, the mobile telephone has a tap detection unit for detecting an impact to the piezoelectric bimorph element due to a finger tap, and the tap detection unit detects an impact to the piezoelectric bimorph element due to a finger tap without going through the backflow prevention means. In accordance with a further specific feature, the tap detection unit has a discrimination unit for discriminating between an impact to the piezoelectric bimorph element due to a finger tap and a collision impact to the piezoelectric bimorph element. 
     In accordance with another feature, there is provided a mobile telephone having: a cartilage conduction unit set in each corner of the upper part of the mobile telephone; a piezoelectric bimorph element serving as a vibration source of the cartilage conduction unit; an analog output amplifier for outputting audio signals to the piezoelectric bimorph element; a tap detection unit for detecting an impact to the piezoelectric bimorph element due to a finger tap; a filter for allowing passage of an impact to the piezoelectric bimorph element due to a finger tap and cutting a band produced by a collision impact to the piezoelectric bimorph element, the filter being disposed between the analog output unit, and the tap detection unit and piezoelectric bimorph element. It is thereby possible to prevent errant detection when the piezoelectric bimorph element serving as a vibration source of the cartilage conduction unit is dually used to detect finger taps. 
     In accordance with another feature, there is provided a mobile telephone having: a cartilage conduction unit set in each corner of the upper part of the mobile telephone; a piezoelectric bimorph element serving as a vibration source of the cartilage conduction unit; an analog output amplifier for outputting audio signals to the piezoelectric bimorph element; and a tap detection unit for discriminating and detecting between an impact to the piezoelectric bimorph element due to a finger tap and a collision impact to the piezoelectric bimorph element. It is thereby possible to prevent errant detection when the piezoelectric bimorph element serving as a vibration source of the cartilage conduction unit is dually used to detect finger taps. 
     In accordance with another feature, there is provided mobile telephone having a piezoelectric bimorph element, and a tap detection unit for detecting an impact to the piezoelectric bimorph element due to a finger tap, the tap detection unit including a discrimination unit for discriminating between an impact to the piezoelectric bimorph element due to a finger tap and a collision impact to the piezoelectric bimorph element. It is thereby possible to prevent errant detection when the piezoelectric bimorph element is used for detecting finger taps. 
     &lt;Forty-First Technical Feature&gt; 
     The forty-first technical aspect disclosed in the present specification provides a mobile telephone having: a sound signal source unit for outputting an audio signal; a cartilage conduction vibration source vibrated by the audio signal from the sound signal source unit; a cartilage conduction unit to which vibrations of the cartilage conduction vibration source are transmitted; and an equalizer for equalizing the audio signal so that the sound pressure in the external auditory meatus produced by direct air conduction and cartilage conduction generated by the cartilage conduction unit is substantially flat in a predetermined frequency region. It is thereby possible to hear satisfactory audio produced by broad-sense cartilage conduction. 
     In accordance with a specific feature, the high-band-side end of the predetermined frequency region is 3.4 kHz or higher. In accordance with another specific feature, the high-band-side end of the predetermined frequency region is 7 kHz or higher. In accordance with yet another specific feature, the low-band-side end of the predetermined frequency region is 300 Hz or lower. 
     In accordance with another specific feature, in the equalization performed by the equalizer, the direct air-conducted sound generated by the cartilage conduction unit is excessive in the high-band portion of the predetermined frequency region. In accordance with a further specific feature, in the equalization performed by the equalizer, the direct air-conducted sound generated by the cartilage conduction unit is excessive in the high-band portion greater than about 3 kHz. 
     In accordance with another feature, there is provided a mobile telephone having: a sound signal source unit for outputting an audio signal; a cartilage conduction vibration source vibrated by the audio signal from the sound signal source unit; a cartilage conduction unit to which vibrations of the cartilage conduction vibration source are transmitted; and an equalizer for equalizing the audio signal so that the direct air-conducted sound generated by the cartilage conduction unit is substantially flat in a predetermined frequency region. A mobile telephone capable of cartilage conduction and in which expected air-conducted sound can be generated is thereby provided. 
     In accordance with another feature, in the equalization performed by the equalizer, the sound pressure in the external auditory meatus produced by direct air conduction and cartilage conduction generated by the cartilage conduction unit is reduced in the high-range portion in the predetermined frequency region. In accordance with a more specific feature, in the equalization performed by the equalizer, the sound pressure in the external auditory meatus produced by direct air conduction and cartilage conduction is reduced in a high-range portion higher than about 3 kHz. 
     In accordance with another feature, there is provided a mobile telephone having: a sound signal source unit for outputting an audio signal; a cartilage conduction vibration source vibrated by the audio signal from the sound signal source unit; a cartilage conduction unit to which vibrations of the cartilage conduction vibration source are transmitted; and an equalizer for equalizing the audio signal so that the external auditory meatus sound pressure produced by cartilage conduction generated by the cartilage conduction unit when the entrance to the external auditory meatus is occluded is substantially flat in a predetermined frequency region. It is thereby possible to hear satisfactory audio when an external auditory meatus occluding effect has occurred. 
     In accordance with another feature, in the equalization performed by the equalizer, the sound pressure in the external auditory meatus produced by direct air conduction and cartilage conduction generated by the cartilage conduction unit is reduced in a high-range portion in the predetermined frequency region. 
     In accordance with another feature, there is provided a mobile telephone having: a sound signal source unit for outputting an audio signal; a cartilage conduction vibration source vibrated by the audio signal from the sound signal source unit; a cartilage conduction unit to which vibrations of the cartilage conduction vibration source are transmitted; and an equalizer capable of switching between equalization of the audio signal in which the sound pressure in the external auditory meatus produced by air conduction and cartilage conduction generated by the cartilage conduction unit is flat in the predetermined frequency region, and equalization in which the direct air-conducted sound generated by the cartilage conduction unit is substantially flat in the predetermined frequency region. It is thereby possible to provide a mobile telephone in which satisfactory audio produced by broad-sense cartilage conduction can be heard and expected air-conducted sound can be generated. 
     In accordance with another feature, there is provided a mobile telephone having: a sound signal source unit for outputting an audio signal; a cartilage conduction vibration source vibrated by the audio signal from the sound signal source unit; a cartilage conduction unit to which vibrations of the cartilage conduction vibration source are transmitted; and an equalizer capable of switching between equalization of the audio signal in which the sound pressure in the external auditory meatus produced by direct air-conducted sound and cartilage-conducted sound generated by the cartilage conduction unit is flat in the predetermined frequency region, and equalization in which the external auditory meatus sound pressure produced by cartilage-conducted sound generated by the cartilage conduction unit when the entrance to the external auditory meatus is occluded is substantially flat in a predetermined frequency region. It is thereby possible to hear satisfactory audio when the external auditory meatus is occluded or unoccluded. 
     In accordance with another feature, there is provided a mobile telephone having: a sound signal source unit for outputting an audio signal; a cartilage conduction vibration source vibrated by the audio signal from the sound signal source unit; a cartilage conduction unit to which vibrations of the cartilage conduction vibration source are transmitted; and control unit for generating from the cartilage conduction unit direct air-conducted sound and cartilage-conducted sound in which the sound pressure in the external auditory meatus is substantially flat in the predetermined frequency region, and generating direct air-conducted sound which is substantially flat in the predetermined frequency region, the air-conducted sound being generated from the cartilage conduction unit in the outer part of the ear. It is thereby possible to provide a mobile telephone in which satisfactory audio produced by broad-sense cartilage conduction can be heard and an expected air-conducted sound can be generated by a single cartilage conduction vibration source. 
     &lt;Forty-Second Technical Feature&gt; 
     The forty-second technical aspect disclosed in the present specification provides a mobile telephone having: a sound signal source unit for outputting an audio signal; an air conduction speaker vibrated by the audio signal from the sound signal source unit; a cartilage conduction unit; and a support structure for supporting the air conduction speaker and transmitting vibrations thereof to the cartilage conduction unit. 
     In accordance with the above configuration, first, a required air-conducted sound can be generated by the air conduction speaker in an ordinary mobile telephone, and the vibrations of the air conduction speaker can also be used and transmitted to the cartilage conduction unit, whereby both cartilage conduction and the generation of air-conducted sound are possible. 
     In accordance with a specific feature, the support structure transmits the counteractions of vibrations generated by the air conduction speaker for air-conducted sound to the cartilage conduction unit. It is thereby possible to use the vibration energy of the air conduction speaker with good efficiency. 
     In accordance with a more specific feature, the cartilage speaker has a first portion and a second portion, air-conducted sound is generated from the first portion by relative movement between the first portion and the second portion, and the second portion is supported by a support structure, whereby the vibrations of the second portion are transmitted to the cartilage conduction unit. It is thereby possible to transmit the counteractions of the vibrations generated by the air conduction speaker for air-conducted sound to the cartilage conduction unit. In accordance with a further specific feature, the first portion and the second portion are weight distributed so that air-conducted sound is generated and cartilage conduction as counteractions thereof occurs. 
     In accordance with another specific feature, the air conduction speaker is an electromagnetic speaker, the first portion is a vibration plate, and the second portion is a holding portion for holding the vibration plate so as to allow vibration. It is thereby possible to configure a mobile telephone using an electromagnetic speaker. 
     In accordance with another more specific feature, the air conduction speaker is a piezoelectric bimorph-type speaker, the first portion is the freely vibrating portion of the piezoelectric bimorph, and the second portion is the support portion of the piezoelectric bimorph. It is thereby possible to configure a mobile telephone using a piezoelectric bimorph-type air conduction speaker. 
     In accordance with another specific feature, the support structure supports the air conduction speaker so that the air conduction speaker does not make contact with other constituent elements of the mobile telephone. It is thereby possible to prevent dispersion of vibration energy to unneeded portions, and to implement cartilage conduction with good efficiency using the generation of air-conducted sound at a required level and the vibrations of the air conduction speaker. 
     In accordance with another specific feature, a cartilage conduction unit is arranged in an upper corner of the mobile telephone. It is thereby possible to configure a practical mobile telephone that makes use of the characteristics of cartilage conduction while also using the vibrations of an air conduction speaker. In accordance with a further specific feature, the air conduction speaker is arranged in the center of the upper part of the mobile telephone. It is thereby possible to conduct a call on a mobile telephone using conventional air-conducted sound. 
     In accordance with another specific feature, a hole for air-conducted sound transit is provided near the air conduction speaker. It is thereby possible to generate air-conducted sound at a required level with good efficiency and to implement cartilage conduction that also uses the vibrations of an air conduction speaker. 
     In accordance with another specific feature, the configuration has an upper frame, the two ends of the upper frame are cartilage conduction units, and the center part of the upper frame is an air conduction speaker support structure. It is thereby possible to use the structure of the upper frame of a mobile telephone to generate air-conducted sound at a required level and implement cartilage conduction with good efficiency. In accordance with a further specific feature, a seating part for an air conduction speaker is provided as an air conduction speaker support structure in the center part of the upper frame. 
     &lt;Forty-Third Technical Feature&gt; 
     The forty-third technical aspect disclosed in the present specification has a sound signal output device having: a sound signal source unit for a cartilage conduction unit; and a frequency characteristics modification unit for modifying the mixture ratio of a direct air conduction component and a cartilage conduction component generated by the cartilage conduction unit, in accordance with the magnitude of change in the sound signal from the sound signal source unit. Listening that is adapted to changes in the magnitude of the sound signal from the sound signal source unit is thereby possible. 
     In accordance with a specific feature, the frequency characteristics modification unit relatively increases the mixture ratio of the cartilage conduction component in relation to the direct air conduction component when the sound signal from the sound signal source unit becomes smaller. It is thereby possible to reduce noise when the sound signal from the sound signal source unit has become smaller, and to adapt to a reduction in audibility of low-pitched regions when the sound signal from the sound signal source unit has become smaller. 
     In accordance with another specific feature, the frequency characteristics modification unit varies the mixture ratio of the direct air conduction component and the cartilage conduction component generated by the cartilage conduction unit in accordance with the temporal change in the magnitude of the sound signal. Listening adapted to changes in the magnitude of the sound signal while, e.g., a song is playing is thereby made possible. In accordance with another specific feature, the frequency characteristics modification unit varies the mixture ratio of the direct air conduction component and the cartilage conduction component generated by the cartilage conduction unit in accordance with the average magnitude of the sound signal. Listening adapted to the average volume is thereby possible. 
     In accordance with another specific feature, the configuration has a signal sending unit, and the output of the frequency characteristics modification unit is sent from the signal sending unit to an external cartilage conduction unit. In accordance with another specific feature, the sound signal output unit is configured as a mobile telephone and the external cartilage conduction unit is configured as a listening device for a mobile telephone. In accordance with another specific feature, the sound signal output unit is configured as a mobile music player, and the external cartilage conduction unit is configured as a listening device for a mobile music player. 
     In accordance with another feature, there is provided a sound signal output unit having: an audio call sound signal source unit for a cartilage conduction unit; a song sound signal source unit for the cartilage conduction unit; and a frequency characteristics modification unit for varying the mixture ratio of the direct air conduction component and the cartilage conduction component generated by the cartilage conduction unit using the sound signal from the audio call sound signal source unit and the sound signal from the music sound signal source unit. It is thereby possible to obtain a mixture ratio of the direct air conduction component and the cartilage conduction component suitable for the audio call sound signal source unit and the music sound signal source unit. In accordance with a specific feature, the frequency characteristics modification unit relatively increases the mixture ratio of the direct air conduction component in relation to the cartilage conduction component in the sound signal from the music sound signal source unit than in the sound signal from the audio call sound signal source unit. 
     In accordance with another feature, there is provided a sound signal output device configured as a mobile telephone and having: a sound signal source unit for incoming call sounds; a sound signal source unit for songs; and a signal sending unit for sending sound signals from the sound signal source unit for songs to an external stereo listening device, and sending sound signals from the sound signal source unit for incoming call sounds in alternating fashion to external left and right stereo listening devices. It is thereby possible to control incoming call sounds with high attention-attracting effect using the fact that the device is a stereo listening device. In accordance with another feature, the stereo listening device is worn on both ears without blocking the ear holes. 
     In accordance with another feature, there is provided a sound signal output device configured as a mobile telephone and having: a sound signal source unit for call sounds; a sound signal source unit for songs; and a signal sending unit for sending sound signals from the sound signal source unit for songs to an external stereo listening device, and, in relation to sound signals from the sound signal source unit for call sounds, distributing and sending the sound signals from different parties to external left and right stereo listening devices. It is thereby possible to carry out a call without confusion using the fact that the device is a stereo listening device. In accordance with another feature, the stereo listening device is worn on both ears without blocking the ear holes. 
     In accordance with another feature, there is provided a stereo listening device worn on both ears without block the ear holes, the stereo listening device having: a sound source signal output unit; an ambient sound detection unit; an ambient sound-cancelling unit for inverting the waveform of ambient sound detected by the detection unit and superimposing the inverted waveform on the sound signal from the sound source signal output unit; and a control unit for stopping the function of the ambient sound-cancelling unit in predetermined conditions. Ambient sound can thereby be heard from unblocked ear holes when required and stereo listening unobstructed by unneeded ambient sound is possible, even though the stereo listening device is worn on both ears. In accordance with another feature, the stereo listening device has a cartilage conduction unit driven by the sound signals of sound source signal output unit in which ambient sound has been inverted in waveform and superimposed. 
     In accordance with another specific feature, a predetermined condition is a rapid increase in the ambient sound detected by the detection unit. It is thereby possible to prevent the danger of being unaware of, e.g., vehicle horns and the like. In accordance with another specific feature, a predetermined condition is a human voice being at a predetermined level or higher as detected by the detection unit. It is thereby possible to prevent the rudeness of being unaware of being spoken to by people nearby. 
     In accordance with another specific feature, the stereo listening device has a receiver for receiving sound signals from a mobile telephone, and when the receiver is receiving an incoming call sound or a call sound, the control unit does not stop the function of the ambient sound-cancelling unit even when the detection unit detects a human voice at a predetermined level or higher. It is thereby possible to give priority being unaware of an incoming call or focusing on a call during a call. 
     &lt;Forty-Fourth Technical Feature&gt; 
     The forty-fourth technical aspect disclosed in the present specification provides a mobile telephone that has a directivity-variable microphone and that automatically switches the directivity of the directivity-variable microphone to the left or right depending on whether the mobile telephone is being held in the left hand or the right hand. It is thereby possible to orient the directivity of the microphone in the direction of the mouth of a user and to pick up the voice of the user without being affected by noise in the area, whether the mobile telephone is being held in the left hand or the right hand. 
     In accordance with a specific feature, the mobile telephone has a cartilage conduction unit provided to both corners in the upper part of the mobile telephone, the directivity of the directivity-variable microphone is automatically switched depending on which cartilage conduction unit has been brought to an ear. In a mobile telephone that uses cartilage conduction, an upper corner of the mobile telephone is brought the ear rather than the center part of the upper end of the mobile telephone, and the tilt during usage is thereby greater than that of an ordinary mobile telephone, and since the microphone tends to be away from the mouth, the configuration is useful in that the directivity of the directivity-variable microphone is automatically switched to the left or right depending on which cartilage conduction unit is brought to the ear. 
     In accordance with another specific feature, the configuration has a tilt detection unit for detecting the tilt of the mobile telephone, and the directivity of the directivity-variable microphone is automatically switched to the left or right in accordance with the tilt detection of the tilt detection unit. In accordance with a yet another specific feature, the configuration has an air conduction speaker, and the orientation of the directivity of the directivity-variable microphone is automatically switched to the center when the air conduction speaker is used. In accordance with a further specific feature, the directivity of the directivity-variable microphone is automatically switched to a wide angle when the mobile telephone is in a horizontal state. 
     In accordance with another feature, the configuration has a directivity-variable microphone and cartilage conduction unit provided to both corners in the upper part of the mobile telephone, and the directivity of the directivity-variable microphone is automatically switched to the left or right depending on which cartilage conduction unit is brought to the ear. It is thereby possible to orient the directivity of the microphone in the direction of the mouth of a user and to pick up the voice of the user without being affected by noise in the area, no matter which cartilage conduction unit has been brought to the ear. 
     In accordance with another feature, there is provided a mobile telephone having a directivity-variable microphone and a tilt detection unit for detecting the tilt of the mobile telephone, the orientation of the directivity of the directivity-variable microphone being automatically switched in response to the detection of the tilt detection unit. It is thereby possible to obtain directivity of the microphone oriented in accordance with the tilt of the mobile telephone. 
     In accordance with another feature, there is provided a mobile telephone having a directivity-variable microphone and tilt detection unit for detecting the tilt of the mobile telephone, the sharpness of the directivity of the directivity-variable microphone being automatically switched in response to the tilt detection of the tilt detection unit. It is thereby possible to obtain directivity of the microphone having a sharpness that corresponds to the tilt of the mobile telephone. 
     In accordance with another feature, there is provided a mobile telephone having a proximity sensor for detecting whether the directivity-variable microphone and the mobile telephone has been brought to the ear, the orientation of the directivity of the directivity-variable microphone being automatically switched in response to the detection of the proximity sensor depending on whether the mobile telephone has been brought to the ear. It is thereby possible to obtain directivity of the microphone having an orientation that corresponds to whether the mobile telephone has been brought to the ear. 
     In accordance with another feature, there is provided a mobile telephone having a proximity sensor for detecting whether the directivity-variable microphone and the mobile telephone has been brought to the ear, the sharpness of the directivity of the directivity-variable microphone being automatically switched in response to the detection of the proximity sensor depending on whether the mobile telephone has been brought to the ear. It is thereby possible to obtain directivity of the microphone having sharpness that corresponds to whether the mobile telephone has been brought to the ear. 
     In accordance with another feature, there is provided a mobile telephone having a directivity-variable microphone, and an air conduction speaker and cartilage conduction unit provided to both corners in the upper part of the mobile telephone, the directivity of the directivity-variable microphone be automatically switched depending on whether the cartilage conduction unit is to be used or the air conduction speaker is to be used. It is thereby possible to obtain directivity of the microphone that corresponds to whether the mobile telephone has been brought to the ear in correspondence to whether the cartilage conduction unit is to be used or whether the air conduction speaker is to be used. 
     In accordance with another feature, there is provided a mobile telephone having a directivity-variable microphone, stereo audio input being processed on the basis of the output of the directivity-variable microphone when the directivity of the directivity-variable microphone is set to a wide angle. It is thereby possible to use the output of the directivity-variable microphone in the stereo audio input when the directivity of the directivity-variable microphone is set to a wide angle. 
     &lt;Forty-Fifth Technical Feature&gt; 
     The forty-fifth technical aspect disclosed in the present specification provides a mobile telephone having: an upper edge part including both corners of the upper part of the mobile telephone where the cartilage conduction units are located, and an elongated piezoelectric bimorph element supported at least at one end by a support part of the inner-side center of upper edge part and used for vibrating essentially without contact with the other portions of the mobile telephone, the vibration of the support part being transmitted from the upper edge part to both corners. It is thereby possible to cause the piezoelectric bimorph element to efficiently vibrate while the vibrations thereof are equally transmitted to the cartilage conduction units in both corners. 
     In accordance with a specific feature, the piezoelectric bimorph element is supported by the support part at one end in the direction that intersects the upper edge part. It is thereby possible to provide an arrangement in which space in not occupied in the direction parallel to the upper edged part even though an elongated piezoelectric bimorph element is used. In accordance with a more specific feature, the piezoelectric bimorph element is supported by the support part at one end perpendicular to the upper edge. 
     In accordance with another specific feature, the piezoelectric bimorph element is supported by the support part at least at one end in the direction parallel to the upper edge part. This configuration is useful when ensuring the piezoelectric bimorph element does not occupy space below the upper edge part. In accordance with another specific feature, the piezoelectric bimorph element is configured so that one end is supported by the support part, and the other end freely vibrates. In accordance with another more specific feature, the piezoelectric bimorph element is configured so that both ends are supported by a pair of support parts provided in the inner-side center of the upper edge part, and the center portion freely vibrates. 
     In accordance with another specific feature, the mobile telephone has an obverse surface plate, and the piezoelectric bimorph element vibrates in the direction perpendicular to the surface plate. It is thereby possible for vibrations in the direction perpendicular to the obverse surface plate to be transmitted to both corners, and for satisfactory cartilage conduction to the ear cartilage to be implemented. In accordance with another specific feature, the mobile telephone has a back surface plate, and the piezoelectric bimorph element is arranged nearer to the obverse surface plate. It is thereby possible for the piezoelectric bimorph element to be arranged so as to occupy no space near the obverse surface plate of the upper part of the mobile telephone. In accordance with a further specific feature, the mobile telephone is configured so as to have an elastic body interposed between the upper edge part and other portions, and so that the vibration energy to the cartilage conduction unit is not scattered to other portions of the mobile telephone. 
     In accordance with another specific feature, an earphone jack is provided to the upper edge part. In accordance with further specific feature, a control unit is provided for performing different equalization in the output to the earphone jack and in the output of the piezoelectric bimorph element. It is thereby possible to perform equalization optimal for output to the earphone jack and output for cartilage conduction. In accordance with a further specific feature, the control unit performs air-conducted sound equalization across a wide range to 20 kHz for the earphone jack, and performs cartilage conduction equalization to 7 kHz for the piezoelectric bimorph element. In accordance with a further specific feature, the control unit performs equalization up to 7 kHz for the earphone jack when a call is carried out through the earphone jack. 
     In accordance with another specific feature, the configuration has determination means for determining the occluded state of the external auditory meatus and superimposing a signal for cancelling one&#39;s own voice on the output audio when the determination means has determined that the external auditory meatus is in an occluded state. Discomfort of hearing one&#39;s own voice when the external auditory meatus is occluded can be reduced. In accordance with a further specific feature, when the determination means has deemed the external auditory meatus to be in an occluded state when a call is carried out through the earphone jack, a signal for cancelling one&#39;s own voice is superimposed on the output audio to the earphone jack. 
     In accordance with another feature, there is provided a mobile telephone characterized in having an upper edge part the includes the both upper part corners of the mobile telephone where the cartilage conduction units are located, a back surface plate, and a cartilage conduction vibration source supported by nearer to the back surface plate of the inner-side center of the upper edge part, the vibrations of the support part being transmitted to both corners from the upper edge part. It is thereby possible for the cartilage conduction vibration source to be arranged without occupying space near the obverse surface plate of the upper part of the mobile telephone. 
     In accordance with another feature, there is provided a mobile telephone having a cartilage conduction unit, an earphone jack, and a control unit for performing different equalization in the output of the audio signal to the earphone jack and in the output of the audio signal to the cartilage conduction unit. It is thereby possible to perform suitable equalization in the output to the earphone jack and the output for cartilage conduction. 
     In accordance with a specific feature, the control unit performs air-conducted sound equalization across a broad range to 20 kHz in the output of the audio signal to the earphone jack, and performs cartilage conduction equalization up to 7 kHz in the output of the audio signal to the cartilage conduction unit. It is thereby possible to perform broad-range equalization with consideration given to playback of a music source when the earphone jack is used, and to give priority to protecting privacy and reducing nuisance to the surroundings, which are advantages of cartilage conduction, and prevent generation of unpleasant air-conducted sound in the surroundings even when there is slight sound leakage of so-called raspy sounds or the like in the output of the audio signal to the cartilage conduction unit. 
     In accordance with another feature, there is provided a mobile telephone having an earphone jack, a signal for cancelling one&#39;s own voice being superimposed on the output audio to the earphone jack when a call has been carried out via the earphone jack. It is thereby possible to reduce discomfort of hearing one&#39;s own voice when the external auditory meatus is occluded by usage of an earphone or the like. 
     &lt;Forty-Sixth Technical Feature&gt; 
     The forty-sixth technical aspect disclosed in the present specification provides a stereo earphone characterized in being provided with a pair of earphones having a cartilage conduction unit composed of an elastic body provided with a passage hole, and a branch part serving as a vibration source, the branch part being connected at one end to the cartilage conduction unit. It is thereby possible to implement a stereo earphone that adapts to the shape of the ear and other personal differences and that is capable of being used for enjoyment of music or the like by satisfactory cartilage conduction with the external auditory meatus in an unoccluded state 
     In accordance with a specific feature, the configuration has a ring-like edge at the outer periphery of the passage hole. The passage hole can thereby be readily occluded using the body of a finger to press on the earphone, and an occluded state of the external auditory meatus can be achieved. 
     In accordance with another specific feature, the branch part has a sheath connected to the cartilage conduction unit, and the piezoelectric bimorph serving as a vibration source is connected to the cartilage conduction unit inside the sheath without being in contact with the inner wall thereof. The branch part can thereby function as a knob when the earphone is to be worn or removed, and no force is applied to the piezoelectric bimorph during wearing or removal. In accordance with a further specific feature, the sheath is configured so as to be capable of sliding with respect to the cartilage conduction unit to open and close the passage hole. The piezoelectric bimorph slides, yet is stably connected to the cartilage conduction unit. 
     In accordance with another feature, there is provided a stereo earphone provided with a pair of earphones having a cartilage conduction unit composed of a deformable elastic body and a branch part serving as a vibration source, one end being connected to the cartilage conduction unit. It is thereby possible to readily switch the external auditory meatus from an occluded state to an unoccluded state by deformation of the cartilage conduction unit. 
     In accordance with specific feature, the branch part has a sheath connected to the cartilage conduction unit, and the piezoelectric bimorph serving as a vibration source is connected to the cartilage conduction unit inside the sheath without being in contact with the inner wall thereof. No force is thereby applied to the piezoelectric bimorph during deformation. In accordance with a further specific feature, the elastic body has a hollow part that facilitates elastic deformation. 
     In accordance with another feature, there are provided stereo earphones characterized in being provided with a pair of earphones having a cartilage conduction unit composed provided with a passage hole, and a branch part serving as a vibration source, one end being slidably connected to the cartilage conduction unit, the passage hole being configured to open and closed by the sliding of the branch part. Provided thereby are stereo earphones that can be used to switch the external auditory meatus from an occluded state to an unoccluded state. 
     In accordance with a specific feature, the branch part has a sheath connected to the cartilage conduction unit, the piezoelectric bimorph serving as a vibration source is connected to the cartilage conduction unit inside the sheath without being in contact with the inner wall thereof, and the passage is opened and closed by the sliding of the sheath. The piezoelectric bimorph itself is thereby stably joined to the cartilage conduction unit without sliding when the passage hold is opened and closed. 
     In accordance with another feature, there are provided stereo earphones characterized in being provided with a pair of earphones having: a cartilage conduction unit which has a shape that allows insertion into the entrance to the external auditory meatus and allows accommodation in the cavum conchae; and a vibration source connected to the cartilage conduction unit. The external auditory meatus can thereby be readily switched between an occluded state and an unoccluded state. In accordance with specific feature, the vibration source is a branch part, one end of which is connected to the cartilage conduction unit. The branch part is used as a knob and the external auditory meatus can thereby be readily switched between an occluded state and an unoccluded state. 
     In accordance with a specific feature, the branch part has a sheath connected to the cartilage conduction unit, and the piezoelectric bimorph serving as a vibration source is connected to the cartilage conduction unit inside the sheath without being in contact with the inner wall thereof. Force is thereby not applied to the piezoelectric bimorph even when the branch part is used as a knob. 
     In accordance with another feature, there is proposed a method for using a cartilage conduction earphone for switching the external auditory meatus between an occluded state and an unoccluded state by inserting the cartilage conduction unit in the entrance to the external auditory meatus or accommodating the cartilage conduction unit in the cavum conchae. It is thereby possible to use the stereo earphones when the external auditory meatus is in an occluded state or an unoccluded state by making use of the structure of the ear. 
     &lt;Forty-Seventh Technical Feature&gt; 
     The forty-seventh technical aspect disclosed in the present specification provides stereo earphones characterized in being provided with a pair of earphones having: a cartilage conduction unit; and a branch part serving as a vibration source, one end being connected to the cartilage conduction unit and the thickness in the ear hole direction being less than the thickness in the direction orthogonal thereto. It is thereby possible for even a person having a narrow intertragic notch to wear the earphone so that the branch part hangs downward from the lower part of the cavum conchae to the intertragic notch, and the earphone can be fitted to the shape of the ear and worn regardless of personal differences. 
     In accordance with a specific feature, the branch part has a sheath connected to the cartilage conduction unit, and the piezoelectric bimorph serving as a vibration source is connected to the cartilage conduction unit inside the sheath without being in contact with the inner wall thereof. In accordance with a further specific feature, the direction of vibration of the piezoelectric bimorph is the direction that transverses the entrance to the external auditory meatus. Since the piezoelectric bimorph vibrates in the direction of low thickness, this setting of the direction of vibration is suitable for configuring the branch part, which has a thickness in the ear hole direction that is less than the thickness in the direction orthogonal thereto. 
     In accordance with another specific feature, the cartilage conduction unit has a passage hole formed in the direction of the ear hole, and a support part for holding the upper end of the piezoelectric bimorph further above the lower end of the passage hole. In accordance with a further specific feature, the cartilage conduction unit has a thick part at the periphery of the passage hole, and the thick part is a support part. Support of the piezoelectric bimorph serving as the vibration source is thereby ensured. In accordance with a further specific feature, the thick part is provided to the tragus side. Cartilage conduction can thereby be implemented with good efficiency. 
     In accordance with another feature, there are provided stereo earphones characterized in being provided with a pair of earphones having: a cartilage conduction unit capable of being accommodated in the cavum conchae; a branch part serving as a vibration source with one end being connected to the cartilage conduction unit, and a movable earplug part supported above the cartilage conduction unit. The movable earplug part can thereby be moved between a position inserted into the entrance to the external auditory meatus and a position removed from the entrance to the external auditory meatus while the cartilage conduction unit is accommodated in the cavum conchae, and it is possible to readily switch between listening by cartilage conduction that does not interfere with hearing external sounds and cartilage conduction with the external auditory meatus in an occluded state. The cartilage conduction unit is preferably accommodated in the lower part of the cavum conchae. 
     In accordance with another feature, the movable earplug part makes contact with the inner wall of the anthelix in a position removed from the entrance to the external auditory meatus. It is thereby possible to stably accommodate the cartilage conduction unit in the cavum conchae when listening by cartilage conduction that does not interfere with hearing external sounds. In accordance with a more specific feature, the movable earplug part is supported in the cartilage conduction unit by a movable lever. 
     In accordance with another specific feature, the movable earplug part is positioned near the entrance to the external auditory meatus in a position removed from the entrance to the external auditory meatus. It is thereby possible to make use of the movable earplug part as an auxiliary vibration part for generating air conduction for listening by cartilage conduction that does not interfere with hearing external sounds. In accordance with a more specific feature, the movable earplug part is supported in the cartilage conduction unit by an elastic body. In accordance with a further specific feature, the cartilage conduction unit and movable earplug part are integrally molded together using an elastic material. 
     In accordance with another feature, there are provided stereo earphones characterized in being provided with a pair of earphones having: a cartilage conduction unit having a passage hole formed through in the ear hole direction and a thick part at the periphery of the passage hole; and branch part serving as a vibration source, one end being connected to the cartilage conduction unit by the thick part further above the lower end of the passage hole. Reliable support of the branch part is thereby made possible. In accordance with a specific feature, the branch part has a sheath connected to the thick part and supports the piezoelectric bimorph serving as a vibration source on the thick part so that the upper end of the piezoelectric bimorph comes further above the lower end of the passage hole without being in contact with the inner wall thereof. It is thereby possible to reliably support the upper end of the piezoelectric bimorph. In accordance with another specific feature, the thick part is provided to the tragus side. 
     In accordance with another feature, there are provided stereo earphones characterized in being provided with a pair of earphones having: a cartilage conduction unit having a passage hole formed through the ear hole direction and a thick part on the tragus side of the passage hole; and a branch part serving as a vibration source supported by the thick part. It is thereby possible to reliably support the branch part serving as a vibration source while making it possible to listen by cartilage conduction with good efficiency without interfering with hearing external sounds through the passage hole. 
     In accordance with another feature, there are provided stereo earphones characterized in being provided with a pair of earphones having: a cartilage conduction unit; and a branch part serving as a vibration source, one end being connected to the cartilage conduction unit and the direction of vibration being in the direction that transverses the entrance to the external auditory meatus. It is thereby possible for vibrations substantially orthogonal to the direction of the external auditory meatus to be transmitted to, e.g., the inner side of the tragus or other ear cartilage. 
     In accordance with another feature, there are provided stereo earphones characterized in being provided with a pair of earphones having: a branch part serving as a vibration source, one end being connected to the cartilage conduction unit; and a guide part provided to the branch part and used for directing the branch part to the intertragic notch. It is thereby possible to stably position the branch part in the intertragic notch when the earphone is worn, and to make the branch part wedge into the intertragic notch with close adhesion so that the earphone is less liable to fall out from the cavum conchae. 
     &lt;Forty-Eighth Technical Feature&gt; 
     The forty-eighth technical aspect disclosed in the present specification provides stereo earphones characterized in being provided with a pair of earphones having a cartilage conduction unit and an adhesive sheet provided to the contact part of the cartilage conduction unit and the ear cartilage. It is thereby possible to prevent the cartilage conduction unit from falling away from the ear cartilage and to implement satisfactory cartilage conduction 
     In accordance with another feature, the adhesive sheet is provided to the portion where the cartilage conduction unit makes contact with the cavum conchae. The cartilage conduction unit can thereby be adhered to the ear cartilage with good efficiency using the adhesive sheet. In accordance with a more specific feature, an earplug part is provided in a position in which the adhesive sheet is not provided in the cartilage conduction unit. It is thereby possible to arbitrarily select a state in which the external auditory meatus is occluded by the earplug part and a state in which external sounds enter through the gap between earplug part and the entrance to the external auditory meatus, and regardless of this selection, the adhesion of the cartilage conduction unit can be maintained by the adhesive sheet. 
     In accordance with another different specific feature, the cartilage conduction unit has an earplug part, and the adhesive sheet is provided to the earplug part. In accordance therewith, it is possible to arbitrarily select a state in which the earplug part is adhered to the entrance to the external auditory meatus and a state in which the earplug part is removed from the entrance to the external auditory meatus and made to adhere to the cavum conchae and the like. 
     In accordance with another feature, there are provided stereo earphones characterized in being provided with a pair of earphones having: a cartilage conduction unit capable of being worn in the entrance to the external auditory meatus; and a plurality of elastic projection parts provided to the cartilage conduction unit so as to be capable of making contact with the entrance to the external auditory meatus. It is thereby possible to prevent the cartilage conduction unit from falling away from the ear cartilage. 
     In accordance with a specific feature, the elastic projection parts are in contact with the entrance to the external auditory meatus in a first worn state in the entrance to the external auditory meatus to thereby create a gap between the cartilage conduction unit and the entrance to the external auditory meatus, and are embedded in the cartilage conduction unit in a second worn state in the entrance to the external auditory meatus to create a state in which the external auditory meatus is occluded by the cartilage conduction unit. It is thereby possible to arbitrarily select a state in which the entrance to the external auditory meatus is occluded by the cartilage conduction unit, and a state in which external sounds enter through a gap between the cartilage conduction unit and the entrance to the external auditory meatus, and it is possible to prevent the cartilage conduction unit from falling out from the entrance to the external auditory meatus regardless of the selection. 
     In accordance with another feature, there are provided stereo earphones characterized in being provided with a pair of earphones having: a cartilage conduction unit; a branch part serving as a vibration source, one end being connected to the cartilage conduction unit; and an additional branch part serving as an additional vibration source, one end being connected to the cartilage conduction unit. It is thereby possible to implement cartilage conduction in a state in which the vibrations of the two vibration sources have been physically mixed in a shared cartilage conduction unit. 
     In accordance with a specific feature, the branch part is arranged so as to fit into the intertragic notch and so that the additional branch part fits into the incisura anterior. The branch part and the additional branch part thereby straddle the tragus, and the positioning and perception of stability is enhanced when the cartilage conduction unit is worn. 
     In accordance with another specific feature, the branch part has a sheath connected to the cartilage conduction unit, the piezoelectric bimorph element serving as a vibration source is connected to the cartilage conduction unit inside the sheath without being in contact with the inner wall thereof, the additionally branch part has an additional sheath connected to the cartilage conduction unit, and the piezoelectric bimorph element serving as an additional vibration source is connected to the cartilage conduction unit inside the additional sheath without being in contact with the inner wall thereof. It is thereby possible to effective protect and support two vibration sources. 
     In accordance with another specific feature, audio signals differently equalized in the vibration source and the additional vibration source are inputted from different channels, respectively. The vibration source and equalization can thereby be apportioned and cartilage conduction of the audio signals can be implemented using effective frequency characteristics. 
     In accordance with another feature, there are provided stereo earphones characterized in being provided with a pair of earphones having: a cartilage conduction unit having a connection part; a piezoelectric bimorph element supported by the connection part; and a sheath connected to the cartilage conduction unit by covering the connection part from the outer side and used for protecting the piezoelectric bimorph element so that there is no contact with the inner wall. This is a useful configuration for connecting the piezoelectric bimorph to the cartilage conduction unit and protecting the piezoelectric bimorph element with the sheath. 
     &lt;Forty-Ninth Technical Feature&gt; 
     The forty-ninth technical aspect disclosed in the present specification provides earphones characterized in having a cartilage conduction unit in close adhesion with the rear outer side of the base of the auricle. It is thereby possible to provide an earphone that does not have a portion for covering the auricle and is capable of a listening style in which the ear hole is open. 
     In accordance with another feature, the cartilage conduction unit is made to closely adhere to the auricle while avoiding the outer-side area above the base of the auricle. Cartilage conduction can thereby be transmitted with good efficiency regardless where the cartilage conduction unit is arranged on the outer side of the ear cartilage, the cartilage conduction unit can be prevented from interfering with the bows of glasses when glasses are being worn, and the configuration is advantageous in that use is allowed regardless of whether glasses are being worn. 
     In accordance with another specific feature, the cartilage conduction unit is made to closely adhere to the base of the auricle facing the mastoid process of the temporal bone. Stable wearing and cartilage conduction with good efficiency are thereby possible. 
     In accordance with a more specific feature, the cartilage conduction unit has a shape that fits and wedges into the gap formed between the base of the auricle and the mastoid process of the temporal bone. In accordance with another specific feature, the cartilage conduction unit has a shape that fits around the base auricle. In accordance with yet another specific feature, the cartilage conduction unit has a shape that fits the outer side of the auricle near the base of the auricle. 
     In accordance with another specific feature, the cartilage conduction unit is bent so as to fit around the base of the auricle. Advantageous wearing on the outer side of the auricle is thereby made possible even when the earphone is elongated. In accordance with another specific feature, the cartilage conduction unit has an adhesive sheet provided so as to closely adhere to the rear outer side of the base of the auricle. In accordance with yet another feature, stereo earphones provided with a pair of earphones are constituted. In accordance with a further specific feature, the pair of earphones has a symmetrical shape so as to fit the reverse sides of the left and right of the auricles. 
     In accordance with another feature, there is provided an earphone characterized in having a cartilage conduction unit and an adhesive sheet provided to the cartilage conduction unit so as to closely adhere to the outer side of the auricle. Stable wearing and cartilage conduction with good efficiency are thereby possible on the outer side of the auricle. In accordance with a specific feature, the cartilage conduction unit is made to closely adhere to the auricle while avoiding the outer-side area above the base of the auricle. 
     In accordance with another specific feature, stereo earphones provided with a pair of earphones are constituted. Stereo earphones in a state in which both ears are open are thereby provided. 
     In accordance with another specific feature, the pair of earphones has a symmetrical shape so as to fit the reverse sides of the left and right of the auricles. Advantageous wearing is thereby possible without confusion of left and right. 
     In accordance with further specific feature, the adhesive sheets of the pair of earphones have mutually symmetrical shapes. It is thereby possible to prevent left-right confusion when the adhesive sheet is replaced. 
     In accordance with another feature, there is provided an earphone characterized in having a pair of earphones having a cartilage conduction unit that closely adheres to the outer side of the auricle, and the pair of earphones has mutually symmetrical shapes. Provided thereby are stereo earphones in which left and right ears are open and in which wearing is possible without left-right confusion. In accordance with a specific feature, the cartilage conduction unit is made to closely adhere to the auricle while avoiding the outer-side area above the left and right bases of the auricles. 
     &lt;Fiftieth Technical Feature&gt; 
     The fiftieth technical aspect disclosed in the present specification provides stereo headphones having: a speaker for generating air-conducted sound, an ear pad for making contact with the auricle; and a cartilage conduction vibration source for transmitting vibrations using the ear pad as a cartilage conduction vibration source. Audio listening enhanced in the high-pitched regions to the low-pitched regions is made possible thereby. 
     In accordance with a specific feature, cartilage conduction vibration source is capable of independently controlling the speaker. In accordance with further specific feature, the cartilage conduction unit and the speaker are driven using audio signals that have been differently equalized. Control that makes use of the features of cartilage conduction and air conduction can thereby be carried out. 
     In accordance with another more specific feature, the headphones have an ambient sound microphone. Ambient sound picked up from the ambient sound microphone are inverted in phase and outputted from the speaker, yet are not outputted from the cartilage conduction vibration source. Noise cancellation of ambient sounds that makes use of the features of cartilage conduction and air conduction can thereby be carried out. 
     In accordance with another more specific feature, the headphones have an ambient sound microphone, and ambient sound picked up from the ambient sound microphone are outputted from the speaker without being inverted in phase, and are not outputted from the cartilage conduction vibration source. Ambient sounds can thereby be introduced while making use of the features of cartilage conduction and air conduction. In accordance with a further specific feature, it is possible to select whether ambient sounds picked up from the ambient sound microphone are to be outputted from the speaker without being inverted in phase. 
     In accordance with another specific feature, the headphones are provided with transmitting means for transmitting the vibrations of the speaker to the ear pad as a cartilage conduction vibration source. Audio listening enhanced by air conduction and cartilage conduction is thereby made possible on the basis of a shared vibration source that makes use of the configuration of the headphones. In accordance with a more specific feature, the speaker is supported by the ear pad to form transmitting means. 
     In accordance with another more specific feature, the headphones have a piezoelectric bimorph element, the center part of the piezoelectric bimorph element is used as a speaker, and both ends of the piezoelectric bimorph element are each supported by the ear pad. In accordance with another more specific feature, the headphones have a piezoelectric bimorph element, one end of the piezoelectric bimorph element is used as the speaker and the other end of the piezoelectric bimorph element is supported by the ear pad. In accordance with these features, audio listening with enhanced air conduction and cartilage conduction is possible using the configuration of the headphones and the configuration of the piezoelectric bimorph. 
     In accordance with another feature, there are provided stereo headphones having a speaker for generating air-conducted sound, a cartilage conduction vibration source, and an ambient sound microphone, ambient sounds picked up from the ambient sound microphone being inverted in phase and outputted from the speaker, yet not being outputted from the cartilage conduction unit. Noise cancellation of ambient sounds that makes use of the features of cartilage conduction and air conduction can thereby be carried out. 
     In accordance with another feature, there are provided stereo headphones having an audio output unit and an ambient sound microphone, the stereo headphones being capable of outputting ambient sounds picked up by the ambient sound microphone from audio output init without being inverted in phase, and selecting whether ambient sounds picked up by the ambient sound microphone are to be outputted from the audio output unit without being inverted in phase or not. The conditions for hearing ambient sounds can thereby be arbitrarily implemented even when the headphones are in use. In accordance with a specific feature, the headphones furthermore has a cartilage conduction vibration source, and ambient sounds picked up from the ambient sound microphone are outputted from the audio output unit without being inverted in phase, and in this process, are not outputted from the cartilage conduction unit. Ambient sounds can thereby be introduced while making use of the features of cartilage conduction and air conduction. 
     In accordance with another feature, there are provided stereo headphones having an audio output unit and an ambient sound microphone, the stereo headphones being capable of selecting whether ambient sounds picked up from the ambient sound microphone are to be inverted in phase and outputted from the audio output unit, or are to be outputted from the audio output unit without being inverted in phase. It is thereby possible to more effectively make use of the ambient sound microphone. In accordance with a specific feature, the headphones have a cartilage conduction vibration source, and ambient sounds picked up from the ambient sound microphone are to be outputted from the audio output unit, or are not to be outputted from the cartilage conduction unit. It is thereby possible to carry out control that matches the traits of ambient sounds and cartilage conduction. 
     In accordance with another feature, there are provided stereo headphones having a speaker for generating air-conducted sound, a cartilage conduction vibration source, and an ambient sound microphone, ambient sounds picked up from the ambient sound microphone being outputted from the speaker, yet not being outputted from the cartilage conduction unit. It is thereby possible to carry out control that matches the traits of ambient sounds and cartilage conduction. 
     &lt;Fifty-First Technical Feature&gt; 
     According to the fifty-first technical feature disclosed herein, a handset has: a data-input touch pen unit for data input on a touch panel of a mobile telephone; a communication unit for near-field wireless communication with the mobile telephone; an audio output unit for output of an audio signal received by the communication unit; and an audio input unit for input of an audio signal transmitted from the communication unit. Thus, the data-input touch pen unit that is useful for input on the touch panel can be used also as a handset, so as to be more valuable as an accessory. 
     According to a more specific feature, the data-input touch pen unit that doubles as a handset is provided with an incoming-call notifying unit. Thus, for example, with the main body of the mobile telephone kept in a bag or the like, a user can recognize an incoming call by vibration or the like of the handset stuck in a chest pocket or the like, and can proceed to conduct a call by using the handset. 
     According to another specific feature, the audio output unit comprises a cartilage conduction unit. Thus, it is possible to provide a handset that exploits the properties of cartilage conduction. With this feature, even with a slim data-input touch pen unit, a user can hear sound reliably by cartilage conduction. 
     According to a more specific feature, the cartilage conduction unit doubles as the incoming-call notifying unit. Thus, the vibration function of cartilage conduction can be used for incoming-call notification. 
     According to another specific feature, the handset is provided with a display unit that displays an identification of the call destination. According to a more specific feature, the handset has a flat shape, and the display unit can display text that identifies the call destination, and is provided on a the flat face of the flat shape. Thus, it is possible to provide a mobile telephone accessory, serving both as a data-input touch pen unit and as a handset, that offers more information so as to be convenient to use. 
     According to another specific feature, the handset has a call destination storage unit. Through selection by a touch with the data-input touch pen unit, call destination data is received from the mobile telephone via the near-field wireless communication unit, and is stored in the call destination storage unit. Thus, it is possible to provide a handset that is more convenient to use when a user conducts a call, for example, with the main body of the mobile telephone kept in a bag or the like. 
     According to another specific feature, a configuration is adopted in which, when the touch panel of the mobile telephone is in a power-saving state, the audio output unit and the audio input unit are in an enabled state. Thus, the function of the handset and the function of the main body of the mobile telephone can be harmonized without confusion. According to a more specific feature, when the touch panel of the mobile telephone is in a state capable of accepting input, the audio output unit and the audio input unit are disused. 
     According to another specific feature, a configuration is adopted in which, when the mobile telephone is in a videophone session, the audio output unit and the audio input unit are in an enabled state. Thus, the function of the handset and the function of the main body of the mobile telephone can be harmonized without confusion. 
     According to another feature, a handset has: a data-input touch pen unit for data input on a touch panel of a mobile telephone; a communication unit for near-field wireless communication with the mobile telephone; and a cartilage conduction unit for output of an audio signal received by the communication unit. Thus, it is possible to configure a handset that exploits the properties of cartilage conduction. Even with a slim data-input touch pen unit, a user can hear sound reliably by cartilage conduction even in a noisy environment. 
     According to another feature, a handset has: a data-input touch pen unit for data input on a touch panel of a mobile telephone; a communication unit for near-field wireless communication with the mobile telephone; and an audio output unit for output of an audio signal received by the communication unit. The handset has a flat shape, and on a flat face of the flat shape, a display unit is provided that can display text that identifies the call destination. Thus, it is possible to provide a mobile telephone accessory, serving both as a data-input touch pen unit and as a handset, that offers more information so as to be convenient to use. 
     &lt;Fifty-Second Technical Feature&gt; 
     According to the fifty-second technical feature disclosed herein, stereo earphones comprise a pair of earphones each having: a cartilage conduction unit held in a space between the inner side of the tragus and the antihelix; a vibration plate arranged in a cavity inside the cartilage conduction unit for generation of air-conduction sound; and a vibration source for conduction of vibration to the cartilage conduction unit and to the vibration plate. 
     With the above configuration, it is possible to provide a stereo earphones that offer high-quality sound by exploiting both cartilage conduction and air conduction owing to a structure held between the inner side of the tragus and the antihelix 
     According to a specific feature, in the cavity inside the cartilage conduction unit, a soft material for supporting the vibration plate is provided. Thus, it is possible to provide stereo earphones that do not interfere with the vibration of the vibration plate and that are less prone to breakage. 
     According to another specific feature, in the cartilage conduction unit, a passage hole is provided through which outside sound is directed to the earhole. The vibration plate is arranged in the cavity inside the cartilage conduction unit so as not to close the passage hole. Thus, it is possible to provide earphones that, by exploiting both cartilage conduction and air conduction, can direct outside sound to the earhole. 
     According to a more specific feature, the passage hole is wider open in a part inward of the vibration plate in a state worn on the ear, than in a part outward of the vibration plate. Thus, air-conduction sound can be directed to the earhole effectively. 
     According to another more specific feature, in the open part of the passage hole inward of the vibration plate in a state worn on the ear, a protector is provided which allows passage of sound but prevents entry of foreign matter. Thus, it is possible to prevent breakage of the internal structure resulting from entry of foreign matter. This is useful when the open part inward of the vibration plate is enlarged with a view to directing air-conduction sound to the earhole effectively. According to a more specific feature, also in the open part of the passage hole outward of the vibration plate in a state worn on the ear, a protector is provided which allows passage of sound but prevents entry of foreign matter. 
     According to another specific feature, a sheath part is provided which is connected to the cartilage conduction unit. The vibration source is a piezoelectric bimorph element that is arranged inside the sheath part such that at least a middle part of the piezoelectric bimorph element does not make contact with the inner wall of the sheath part. The vibration of the piezoelectric bimorph element is conducted to the cartilage conduction unit and to the vibration plate. Thus, it is possible to provide stereo earphones that can achieve cartilage conduction and generate air-conduction sound effectively by using the piezoelectric bimorph element as a vibration source. 
     According to a more specific feature, the cartilage conduction unit comprises an elastic member, and the sheath part comprises a hard material that is connected to the elastic member. The cartilage conduction unit is supported such that the piezoelectric bimorph element does not make contact with the inner wall of the hard material. Thus, it is possible to provide stereo earphones that can achieve cartilage conduction and generate air-conduction sound effectively with little leakage of sound. According to a still more specific feature, the vibration unit is supported on the piezoelectric bimorph element so as not to make direct contact with the cartilage conduction unit. 
     According to another more specific feature, the cartilage conduction unit comprises an elastic member, and the sheath part comprises a hard material that is connected to the elastic member. One end of the piezoelectric bimorph element is supported on the cartilage conduction unit, and the other end of the piezoelectric bimorph element is supported on the sheath part, so that a middle part of the piezoelectric bimorph element does not make contact with the inner wall of the hard material. Thus, the sheath part can be used as a fulcrum for the vibration of the cartilage conduction unit comprising the elastic member. According to a still more specific feature, the vibration unit is supported on an extension part that is extended from the sheath part to the cavity inside the cartilage conduction unit. Thus, the vibration of the sheath part can be used to generate air-conduction sound. 
     According to another more specific feature, one end of the piezoelectric bimorph element is supported on the sheath part, and the vibration plate is supported on the other end of the piezoelectric bimorph element. Thus, while cartilage conduction is achieved, air-conduction sound can be generated effectively. According to a still more specific feature, the cartilage conduction unit comprises a hard material. 
     &lt;Fifty-Third Technical Feature&gt; 
     According to the fifty-third technical feature disclosed herein, a wrist watch-type handset has a cartilage conduction unit for achieving cartilage conduction by contact with the ear cartilage. Thus, it is possible to provide a convenient-to-use handset that exploits cartilage conduction. 
     For the wrist watch-type handset above, a call-conducting method is proposed in which a user obtains cartilage conduction by holding the arm on which the wrist watch is worn across the face so that the wrist watch makes contact with the ear on the opposite side. Thus, call-conducting is possible in a natural posture. According to a specific feature, the wrist watch-type handset has a display unit, which is brought into contact with the ear. According to another specific feature, the wrist watch-type handset has a belt part which is wound around the wrist, which is brought into contact with the ear. 
     In another call-conducting method proposed for the wrist watch-type handset above, a user obtains cartilage conduction by bringing the palm-side face of the wrist watch into contact with the ear on the same side as the arm on which the wrist watch is worn. 
     In yet another call-conducting method proposed, a user obtains cartilage conduction by brining the arm on which the wrist watch is worn into contact with the ear. 
     Also proposed is a wrist watch-type handsets that is offered along with information about call-conducting methods as described above. Thus, a user can understand different call-conducting methods with the wrist watch-type handset correctly. Specifically, a wrist watch-type handset has a means for displaying information about call-conducting methods. In another specific example, a wrist watch-type handset is offered along with an instruction providing medium that contains information about call-conducting methods. In yet another specific example, a wrist watch-type handset is offered along with an advertising medium that contains information about call-conducting methods. 
     According to another feature, a wrist watch-type handset has: a cartilage conduction unit for achieving cartilage conduction by contact with the ear cartilage; and a display unit for displaying information about a call-conducting method using the cartilage conduction unit. 
     According to another feature, a wrist watch-type handset has: a cartilage conduction unit for achieving cartilage conduction by contact with the ear cartilage; and a microphone having directivity pointing from the wrist to the elbow. Thus, it is possible to provide a handset that is effective in the proposed call-conducting postures. 
     According to another feature, a wrist watch-type handset has: a near-field communication unit for communication with a mobile telephone; and a means for exchanging information about each other&#39;s power status for coordination with the mobile telephone. Thus, it is possible to achieve coordination between the mobile telephone and the wrist watch-type handset, and thus to avoid a situation where the function of either is unavailable. 
     According to another feature, a wrist watch-type handset has: a near-field communication unit for communication with a mobile telephone; and a means for checking the feasibility of communication with the mobile telephone by the near-field communication unit for coordination with the mobile telephone. Thus, it is possible to achieve coordination between the mobile telephone and the wrist watch-type handset, and thus to avoid a situation where the function of either is unavailable. 
     According to another feature, a wrist watch-type handset has: a near-field communication unit for communication with a mobile telephone; and a means for sending to the mobile telephone a signal for checking the location of the mobile telephone for coordination with the mobile telephone. Thus, it is possible to achieve coordination between the mobile telephone and the wrist watch-type handset, and thus to avoid a situation where the function of either is unavailable. 
     &lt;Fifty-Fourth Technical Feature&gt; 
     According to the fifty-fourth technical feature disclosed herein, a handset has: a cartilage conduction unit for achieving cartilage conduction by contact with the ear cartilage; and a name tag display unit. Thus, it is possible to conduct a call by cartilage conduction using a name tag which a user wears all the time. 
     According to a specific feature, the display unit inverts what it is displaying upside down according to the position of the handset. According to another specific feature, the handset has a near-field communication unit for communication with a mobile telephone. According to another specific feature, the handset has a neck strap part. When the handset is suspended via the neck strap part, the cartilage conduction unit is located under the name tag display unit. According to a more specific feature, the handset has an incoming-call vibration source. The neck strap part is connected to the handset such that the handset can be suspended from the neck, and conducts the vibration of the incoming-call vibration source to the neck. According to another specific feature, the incoming-call vibration source is activated by an incoming-call signal from the mobile telephone, and the name tag display unit displays whether or not the mobile telephone is set to a silent mode. According to another specific feature, the name tag display unit displays the charge status of the mobile telephone. According to another specific feature, the handset has the function of a non-contact IC card. 
     According to another feature, a handset has: an incoming-call vibration source that is activated by an incoming-call signal from a mobile telephone; and a display unit that displays whether or not the mobile telephone is set to a silent mode. Thus, it can be indicated to a person present in front that the mobile telephone is set to a silent mode. According to a specific feature, a name tag can be displayed on the display unit to present information to other people. According to another specific feature, the handset has a neck strap part. 
     According to another feature, a handset has: an incoming-call vibration source that is activated by an incoming-call signal from a mobile telephone; and a display unit that displays the charge status of the mobile telephone. Thus, the charge state of the mobile telephone can be indicated to a person present in front. 
     According to another feature, a handset has an incoming-call vibration source that is activated by an incoming-call signal from a mobile telephone, and has the function of a non-contact IC card. Thus, it is possible to provide a handset that has both the function of a non-contact IC card and the function of an incoming-call vibration function. 
     According to another feature, a handset has a cartilage conduction unit for achieving cartilage conduction by contact with the ear cartilage, and has the function of a non-contact IC card. Thus, it is possible to conduct calls by cartilage conduction using the function of a non-contact IC card. 
     According to another feature, a handset has: an incoming-call vibration source that is activated by an incoming-call signal from a mobile telephone; and a neck strap part connected to the incoming-call vibration source. The vibration of the incoming-call vibration source is conducted to the neck. Thus, it is possible to recognize an incoming call reliably. 
     According to another feature, a name tag has: an incoming-call vibration source that is activated by an incoming-call signal from a mobile telephone; and a neck strap part connected to the incoming-call vibration source. The vibration of the incoming-call vibration source is conducted to the neck. Thus, it is possible to recognize an incoming call reliably by use of the name card suspended via the neck strap. 
     According to another feature, a name tag has a name tag display unit. The top/bottom direction of what is displayed on the name tag display unit can be inverted according to a user&#39;s posture. Thus, a user can easily view information directed to himself by use of the name tag which displays information for other people. 
     According to another feature, a non-contact IC card has: a non-contact IC card function unit; an incoming-call vibration source that is activated by an incoming-call signal from a mobile telephone; and a neck strap part connected to the incoming-call vibration source. The vibration of the incoming-call vibration source is conducted to the neck. Thus, it is possible to recognize an incoming call reliably by use of the non-contact IC card. 
     &lt;Fifty-Fifth Technical Feature&gt; 
     According to the fifty-fifth technical feature disclosed herein, a mobile telephone has: a pair of cartilage conduction units arranged at opposite top corners respectively and having an acoustic impedance close to that of the ear cartilage, for achieving cartilage conduction by contact with the ear cartilage; a linking unit having an acoustic impedance close to that of the ear cartilage, for linking together the pair of cartilage conduction units; a casing top-face part for supporting, while having a different acoustic impedance from, the pair of cartilage conduction units and the linking unit; and a cartilage conduction vibration source supported on the linking unit without making contact with the casing top-face part. Thus, with either of the pair of cartilage conduction units put in contact with the ear cartilage, satisfactory cartilage conduction is achieved. In addition, owing to the difference in acoustic impedance, conduction of the vibration of the cartilage conduction vibration source to the casing can be suppressed. Moreover, the above feature is useful for arranging a structure for cartilage conduction without occupying too much space inside the casing top-face part, which tends to be congested with components. 
     According to another specific feature, the linking unit is bonded to the casing top-face part. Thus, the linking unit is supported reliably, and vibration in the direction perpendicular to the surface is suppressed by the casing top-face part. Accordingly, even with the linking unit supported outward of the casing top-face part so as to be exposed outside, air-conduction sound is prevented from being generated from the surface of the linking unit. 
     According to another specific feature, the linking unit is supported outward of the casing top-face part. According to a more specific feature, the casing top-face part has an opening, and the cartilage conduction vibration source is supported in the opening, inward of the surface of the casing top-face part. Thus, despite the linking unit being located outward of the casing top-face part, the cartilage conduction vibration source can be supported inward of the surface of the casing top-face part without making contact with the casing top-face part. 
     According to another specific feature, the cartilage conduction vibration source is embedded in the linking unit. Thus, the cartilage conduction vibration source can be supported on the linking unit without making contact with the casing top-face part. 
     According to another specific feature, the casing top-face part has an opening, and the cartilage conduction vibration source is supported inward of the linking unit, near the opening. Also with an opening provided in the casing top-face part so that the cartilage conduction vibration source is supported inward of the linking unit in this way, the cartilage conduction vibration source can be supported without making contact with the casing top-face part. 
     According to a more specific feature, the entire cartilage conduction vibration source is bonded to the linking unit. This configuration is particularly useful for arranging a structure for cartilage conduction without occupying too much space inside a casing top-face part, which tends to be congested with components. According to another specific feature, the cartilage conduction vibration source has an elongated shape. Of the cartilage conduction vibration source, at least one end is supported on the linking unit, and at least a central part vibrates freely. 
     According to another specific feature, the linking unit is supported inward of the casing top-face part, and is linked to the pair of cartilage conduction units through openings provided in the opposite corners respectively, With this configuration, where the linking unit is located inward of the casing top-face part, the vibration of the linking unit hardly contributes to generation of air-conduction sound. 
     According to another specific feature, the pair of cartilage conduction units covers at least the top face, the front face, and the side face of the top corner parts. With this configuration, owing to an increased contact area between the cartilage conduction units and the ear cartilage, more efficient cartilage conduction can be achieved. In addition, the so designed cartilage conduction units provide one of those structures which are suitable to protect the corner parts as when the mobile telephone is dropped. According to another specific feature, the linking unit covers at least the front face of the casing top-face part. Thus, the linking unit has a broader conduction path. Moreover, even with the middle of the top-face part put on the ear cartilage as with a common mobile telephone, the vibration of the linking unit conducts to the ear cartilage. Thus, cartilage conduction is achieved, with the linking unit too acting as a cartilage conduction unit. 
     According to another feature, a mobile telephone has: a cartilage conduction unit having an acoustic impedance close to that of the ear cartilage, for achieving cartilage conduction by contact with the ear cartilage; a casing top-face part for supporting, while having a different acoustic impedance from, the cartilage conduction unit; a cartilage conduction vibration source arranged inward of the casing top-face part, for conducting cartilage conduction vibration to the cartilage conduction unit; and a linking unit supported on the casing top-face part and supporting, inward of it, the cartilage conduction vibration source such that this does not make contact with the casing top-face part, the linking unit being linked to the cartilage conduction unit through an opening provided in the casing top-face part, the linking unit having an acoustic impedance close to that of the ear cartilage. Thus, with the cartilage conduction unit put in contact with the ear cartilage, satisfactory cartilage conduction can be achieved. In addition, owing to the difference in acoustic impedance, conduction of the vibration of the cartilage conduction vibration source to the casing can be suppressed. Moreover, the above feature is useful for arranging a structure for cartilage conduction without occupying too much space inside the casing top-face part, which tends to be congested with components. According to a specific feature, the linking unit is supported outward of the casing top-face part, and supports the cartilage conduction vibration source inward of the casing top-face part such that this does not make contact with the casing top-face part. According to another specific feature, the linking unit is supported inward of the casing top-face part, supports the cartilage conduction vibration source such that this does not make contact with the casing top-face part, and is linked to the cartilage conduction through the opening. 
     According to a specific feature, the cartilage conduction unit and the linking unit are elastic members. An elastic member is suitable as a material having an acoustic impedance close to that of the ear cartilage. With this configuration, the corner parts are protected from impact when the mobile telephone is dropped. In addition, owing to the cartilage conduction vibration source being supported only by an elastic member, this serves as a shock-absorbing material, and prevents the cartilage conduction vibration source from being destroyed by impact as when the mobile telephone is dropped. According to another specific feature, the cartilage conduction vibration source is a piezoelectric bimorph element. According to another specific feature, the cartilage conduction vibration source is an electromagnetic vibrating element. 
     &lt;Fifty-Sixth Technical Feature&gt; 
     According to the fifty-sixth technical feature disclosed herein, a mobile telephone has: a pair of cartilage conduction units arranged in opposite top corners, respectively, of the mobile telephone and having an acoustic impedance close to that of the ear cartilage, for achieving cartilage conduction by contact with the ear cartilage; a vibration-conducting member formed of a material having a better vibration-conducting property than the pair of cartilage conduction units, the vibration-conducting member being supported, at opposite ends, on the pair of cartilage conduction units; and a cartilage conduction vibration source supported on the vibration-conducting member. Thus, it is possible to provide a mobile telephone that offers satisfactory cartilage conduction while suppressing generation of air-conduction sound. 
     According to another feature, a mobile telephone has: a pair of cartilage conduction units arranged in opposite top corners, respectively, of the mobile telephone, for achieving cartilage conduction by contact with the ear cartilage; a vibration-conducting member formed of a material having a better vibration-conducting property than the pair of cartilage conduction units, the vibration-conducting member being supported, at opposite ends, on the pair of cartilage conduction units; and a cartilage conduction vibration source supported on the vibration-conducting member. Thus, it is possible to provide a mobile telephone that offers satisfactory cartilage conduction while suppressing generation of air-conduction sound and that can protect the cartilage conduction vibration source from impact from outside. 
     According to a specific feature, the vibration-conducting member is configured so as not to make contact with a casing top-face part of the mobile telephone. Thus, generation of air-conduction sound can be prevented effectively. More specifically, there is provided a linking unit either having an acoustic impedance close to that of the ear cartilage or formed of an elastic member, for linking together the pair of cartilage conduction units, so that the vibration-conducting member is supported also on the linking unit. Still more specifically, the linking unit is supported inward of the casing top-face part of the mobile telephone. Or a structure is adopted where the vibration-conducting member floats off the casing top-face part of the mobile telephone. 
     According to another specific feature, the vibration-conducting member is configured so as not to make contact with the front face and the rear face of the casing of the mobile telephone. Thus, generation of air-conduction sound from the front face and the rear face of the casing is suppressed. According to a more specific feature, the front face and the rear face of the casing of the mobile telephone are formed of a hard material. 
     According to another specific feature, the vibration-conducting member is configured so as not to make contact with an earphone jack provided in the casing top-face part of the mobile telephone. Thus, the vibration-conducting member can be arranged such that no air-conduction sound is generated from an earphone jack or the like that is exposed on the outer wall from inside the mobile telephone. 
     According to another specific feature, the vibration-conducting member is configured so as not to make contact with a power switch provided in the casing top-face part of the mobile telephone. Thus, the vibration-conducting member can be arranged such that no air-conduction sound is generated from a power switch or the like that is exposed on the outer wall from inside the mobile telephone. 
     According to another specific feature, the cartilage conduction vibration source is arranged in a middle part of a top-face part of the casing of the mobile telephone. Thus, the cartilage conduction vibration source can be vibrated in a well-balanced manner, and its vibration can be conducted to the cartilage conduction unit. 
     According to another feature, a mobile telephone has: a pair of cartilage conduction units arranged in opposite top corners, respectively, of the mobile telephone, for achieving cartilage conduction by contact with the ear cartilage; and a cartilage conduction vibration source for conducting vibration to the pair of cartilage conduction units. Generation of air-conduction sound from the front face of the mobile telephone at the opposite corners is suppressed compared with that from the top face and the side face of the mobile telephone at the opposite corners. Thus, the direct air-conduction sound component that enters the external auditory meatus from the cartilage conduction unit can be reduced. 
     According to another feature, an earphone has: a cartilage conduction unit for achieving cartilage conduction by contact with the ear cartilage; and a cartilage conduction vibration source for conducting vibration to the cartilage conduction unit. Generation of air-conduction sound from the face of the cartilage conduction unit that, when worn, faces the external auditory meatus is suppressed compared with that from the circumferential face of the cartilage conduction unit that makes contact with the ear cartilage. Thus, the direct air-conduction sound component that enters the external auditory meatus from the cartilage conduction unit can be reduced. According to a specific feature, the cartilage conduction unit has a passage hole through which air-conduction sound is passed from outside to the external auditory meatus. Generation of air-conduction sound from the inner face of the passage hole is suppressed compared with that from the side circumferential face of the cartilage conduction unit. 
     According to another feature, an earphone has: a cartilage conduction unit for achieving cartilage conduction by contact with the ear cartilage and for passing therethrough air-conduction sound from outside to the external auditory meatus; and a cartilage conduction vibration source for conducting vibration to the cartilage conduction unit. Generation of air-conduction sound from the inner face of the passage hole is suppressed compared with that from the side circumferential face of the cartilage conduction unit. Thus, the direct air-conduction sound component that enters the external auditory meatus from the cartilage conduction unit can be reduced. 
     &lt;Fifty-Seventh Technical Feature&gt; 
     According to the fifty-seventh technical feature disclosed herein, a mobile telephone has a front wall, a rear wall, a top wall partly continuous with a side face, and a side wall, and includes: a vibration-absorbing material provided between the top wall and each of the front wall, the rear wall, and the side wall; and a cartilage conduction vibration source provided on the inner side of the top wall. Opposite corner parts of the top wall partly continuous with the side face serve as a cartilage conduction unit. Thus, it is possible to provide a cartilage conduction mobile telephone with suppressed generation of air-conduction sound. 
     According to a specific configuration, the front wall, the rear wall, the top wall, and the side wall are formed of a hard material. According to another specific configuration, the cartilage conduction vibration source is a piezoelectric bimorph element. According to yet another specific configuration, the cartilage conduction vibration source is affixed to the inner side of the top face. 
     According to another feature, a mobile telephone has: a front wall; a pair of cartilage conduction units arranged at opposite top corners, respectively, of the mobile telephone; a vibration-conducting member for conducting vibration to the pair of cartilage conduction units; a cartilage conduction vibration source supported on the vibration-conducting member; a vibration-absorbing material for supporting the vibration-conducting member such that this does not make contact with the front wall; and a switching unit for switching whether or not to conduct the vibration of the vibration-conducting member to the front wall. Thus, it is possible to provide a compactly-designed cartilage conduction mobile telephone that generates little air-conduction sound. As necessary, it is also possible to generate air-conduction sound as required in a common mobile telephone. 
     According to a specific configuration, the cartilage conduction unit has an acoustic impedance close to that of the ear cartilage. According to another specific feature, the switching unit can be operated from outside the mobile telephone. 
     According to a specific configuration, the mobile telephone has a linking unit formed of an elastic member for linking together the pair of cartilage conduction units, and the vibration-conducting member is supported also on the linking unit. According to another specific configuration, the vibration-conducting member floats off the casing top-face part. 
     According to another feature, a mobile telephone has a cartilage conduction unit, and determines the frequency characteristics of an audio signal for driving the cartilage conduction unit based on the language of the audio signal. Thus, it is possible to provide a mobile telephone that can deal with different languages. According to a specific feature, the frequency characteristics of the audio signal is changed by an electric circuit. According to another specific feature, the frequency characteristics of the audio signal is changed mechanically. 
     According to another specific feature, the frequency characteristics of the audio signal can be changed either by manual operation or by an automatic means, and a change by manual operation is given priority over a change by the automatic means. Thus, it is possible to provide a mobile telephone that prevents operation unintended by the user. According to a more specific feature, a change by the automatic means is invalidated for a predetermined period after a change by manual operation. 
     According to another specific feature, the mobile telephone has a display unit, and switches the display language on the display unit based on language. Even when the display language is switched between languages having similar frequency characteristics, the frequency characteristics of the audio signal for driving the cartilage conduction vibration source are not changed. Thus, the display language and the frequency characteristics can be changed in an intelligent manner. According to another specific feature, the mobile telephone has a display unit, and automatically changes the frequency characteristics of the audio signal for driving the cartilage conduction vibration source based on the switching of the display language on the display unit. Thus, the frequency can be changed automatically based on the change of the display language, both being related to language. 
     According to another specific feature, the mobile telephone has a location detecting unit, and automatically changes the frequency characteristics of the audio signal for driving the cartilage conduction vibration source based on the detected location. Thus, the frequency can be changed automatically based on the language region in which the mobile telephone is located. 
     According to another specific feature, the mobile telephone has an incoming-call sound analyzing unit, and the frequency can be changed automatically based on the language inferred by the incoming-call sound analyzing unit. 
     &lt;Fifty-Eighth Technical Feature&gt; 
     According to the fifty-eighth technical feature disclosed herein, a mobile telephone has an adjusting means for adjusting the intensity of the vibration for cartilage conduction that results from contact with the ear cartilage at least between a first intensity and a second intensity. The mobile telephone generates air-conduction sound whose volume changes with change of the intensity of the vibration. The first intensity of vibration is an intensity sufficient to generate air-conduction sound with a volume needed in a measurement method conforming to a standard for a common mobile telephone. The second intensity is an intensity insufficient to generate air-conduction sound with the volume needed in the measurement method conforming to the standard for a common mobile telephone, and the sound pressure inside the external auditory meatus as measured with the mobile telephone in contact with the ear cartilage with the vibration at the second intensity is higher than the sound pressure inside the external auditory meatus as measured with the mobile telephone out of contact with but close to the entrance of the external auditory meatus with the vibration at the first intensity. Thus, it is possible to provide a mobile telephone that conforms to a standard for a common mobile telephone and that in addition achieves effective cartilage conduction. 
     According to a specific feature, the mobile telephone has a front wall, a rear wall, a top wall, and a side wall, wherein a vibration source for the vibration is arranged on the inner side of the top wall, and the air-conduction sound is generated by conducting vibration from the top wall to the front wall. Thus, effective cartilage conduction and air-conduction sound generation can be achieved. 
     According to a more specific feature, the vibration source has a thin shape, vibrates in the direction perpendicular to the thin shape, and is affixed to the inner side of the top wall in the direction parallel to the thin shape. Thus, a space is secured for arranging various components in a top part of the mobile telephone. 
     According to a more specific feature, the vibration source is arranged at the middle, in the left/right direction, of the top wall. A front camera is arranged at the middle, in the left/right direction, of the inner side of the top wall. According to another specific feature, a proximity sensor unit is arranged at the middle, in the left/right direction, of the inner side of the top wall. In the arrangements described above, the vibration source is preferably a piezoelectric bimorph element. 
     According to another specific feature, the rear wall, the top wall, and the side wall constitute an integral box-shaped casing, which, when combined with the front wall, permits vibration to conduct from the top wall to the front wall. Thus, cartilage conduction and air-conduction sound generation are possible with a practical casing structure. 
     According to another feature, a mobile telephone has a front wall, a rear wall, a top wall, and a side wall, wherein a cartilage conduction vibration source that has a thin shape and that vibrates in the direction perpendicular to the thin shape is affixed to the middle, in the left/right direction, of the inner side of the top wall in the direction parallel to the thin shape, and a front camera is arranged at the middle, in the left/right direction, of the inner side of the top wall. Thus, a user can shoot his own face from in front when conducting a videophone session or when shooting himself. 
     According to another feature, a mobile telephone has a front wall, a rear wall, a top wall, and a side wall, wherein a cartilage conduction vibration source that has a thin shape and that vibrates in the direction perpendicular to the thin shape is affixed to the middle, in the left/right direction, of the inner side of the top wall in the direction parallel to the thin shape, and a proximity sensor unit is arranged at the middle, in the left/right direction, of the inner side of the top wall. Thus, in a case where a corner part is used as a cartilage conduction unit, irrespective of whether a right corner part is put on the right ear cartilage or a left corner part is put on the left ear cartilage, contact of the mobile telephone can be detected reliably. In these configurations, the vibration source is preferably a piezoelectric bimorph element. 
     According to another feature, a mobile telephone has a front wall, a rear wall, a top wall, and a side wall, and includes: a cartilage conduction vibration source arranged on the inner side of the top wall; and a explanation unit for explaining a method of use in which the top wall is used as a cartilage conduction unit when, with a user&#39;s face pointing ahead, the mobile telephone is held transversely, roughly horizontally, and is put on a front edge part of the entrance of the external auditory meatus. According to a more specific feature, the explanation unit explains a method of use in which the top wall is used as a pressing part for bending the tragus to close the entrance of the external auditory meatus when, with a user&#39;s face pointing ahead, the mobile telephone is moved rearward. Thus, the mobile telephone can be used properly by exploiting the top wall. 
     According to another feature, in a method for using a mobile telephone having a front wall, a rear wall, a top wall, and a side wall and including a cartilage conduction vibration source arranged on the inner side of the top wall, the top wall is used as a cartilage conduction unit when, with a user&#39;s face pointing ahead, the mobile telephone is held transversely, roughly horizontally, and is put on a front edge part of the entrance of the external auditory meatus. According to a specific feature, in the above method of use, the top wall is used as a pressing part for bending the tragus to close the entrance of the external auditory meatus when, with a user&#39;s face pointing ahead, the mobile telephone is moved rearward. Thus, the mobile telephone can be used by exploiting the top wall effectively. 
     According to another feature, an explanation medium explains a method of use of a mobile telephone as described above. The explanation medium is, for example, one or a combination of a display unit of a mobile telephone, a speaker of a mobile telephone, an instruction manual of a mobile telephone, a pamphlet of a mobile telephone, and a means for advertising a mobile telephone. Thus, the mobile telephone can be used by exploiting the top wall. 
     &lt;Fifth-Ninth Technical Feature&gt; 
     According to a fifty-ninth technical feature disclosed herein, a mobile telephone has a display face which is provided on the front face of a casing and which has a touch panel function, a cartilage conduction vibration source which is provided at the center of the inside of a top side part of the casing so as not to make contact with the display face, and an anti-vibration material which is interposed between the display face and the other part of the casing. It is thus possible to suppress generation of air-conduction sound from the display face having a large area. 
     According to a specific feature, the display face at its top end reaches the top side part of the casing. This feature is useful to suppress generation of air-conduction sound from the display face having a larger area. 
     According to another specific feature, the display face is provided with a vibration-suppressing structure. It is thus possible to further suppress generation of air-conduction sound. More specifically, the vibration-suppressing structure is a weight part provided on the display face so as not to make contact with other than the display face. Or the vibration-suppressing structure connects the display face to a weight structure inside the mobile telephone. Or the vibration-suppressing structure is an elastic body held between the display face and another structure inside the mobile telephone. 
     According to another specific feature, The cartilage conduction vibration source is arranged with its vibration direction perpendicular to the top side part of the casing. Or the cartilage conduction vibration source is arranged at the center of the top side part with its vibration direction perpendicular to the display face. Or the cartilage conduction vibration source is arranged with its vibration direction inclined relative to both the display face and the top side part of the casing. 
     According to another specific feature, there is provided a vibration limiter unit which limits vibration of the cartilage conduction vibration source. It is thus possible to suppress excessive vibration when cartilage conduction occurs. 
     According to a more specific feature, the vibration limiter unit limits vibration on the condition that the top side part of the mobile telephone makes contact with the ear. According to another specific feature, the top side part of the mobile telephone that makes contact with the ear is a corner part of a top part of the mobile telephone. 
     According to another specific feature, the vibration limiter unit limits vibration on the condition that the external auditory meatus is closed by the pressure with which the top side part of the mobile telephone makes contact with the ear. 
     According to another feature disclosed herein, a mobile telephone has a display face which is provided on the front face of a casing and which has a touch panel function, a cartilage conduction vibration source which is provided at the center of the inside of a top side part of the casing so as not to make contact with the display face, and a vibration limiter unit which limits vibration of the cartilage conduction vibration source. It is thus possible to suppress excessive vibration when cartilage conduction occurs. 
     According to a more specific feature, the vibration limiter unit limits vibration on the condition that the top side part of the mobile telephone makes contact with the ear. It is thus possible to suppress excessive vibration, for example, when an air-conduction sound generation test is performed and thereafter the mobile telephone is put on the ear with no change in the sound volume setting. According to a more specific feature, the top side part of the mobile telephone that is put on the ear is a corner part of a top part of the mobile telephone. 
     According to another specific feature, the vibration limiter unit limits vibration on the condition that the external auditory meatus is closed by the pressure with which the top side part of the mobile telephone makes contact with the ear. It is thus possible to suppress excessive vibration, for example, when an air-conduction sound generation test is performed and thereafter the mobile telephone is put firmly on the ear with no change in the sound volume setting. 
     &lt;Sixtieth Technical Feature&gt; 
     According to a sixtieth technical feature disclosed herein, a mobile telephone has a display face which is provided on the front face of a casing and which has a touch panel function, a rear face, a top face which lies between the display face and the rear face, a vibration-absorbing material which is interposed between the display face and the top face and between the rear face and the top face, and a vibration source which conducts vibration to the top face. It is thus possible to suppress generation of air-conduction sound from the display face and the rear face. 
     According to a specific feature, the display face at its top end reaches near the top face. This configuration is suitable to build a mobile telephone in which the top end of the display face reaches near the top face. 
     According to another specific feature, the mobile telephone has both side faces and a bottom face which lie between the display face and the rear face, and the vibration-absorbing material is interposed between, at one end, the display face and, at the other end, the both side faces and the bottom face and between, at one end, the rear face and, at the other end, the both side faces and the bottom face. Thus, the display face and the rear face are at their periphery isolated from the top face, both side faces, and the bottom face, and this makes it possible to effectively suppress generation of air-conduction sound. 
     According to another specific feature, the mobile telephone has a coupling structure which couples together the display face and the rear face so as to hold the top face between the display face and the rear face with the vibration-absorbing material interposed in between. It is thus possible to effectively interpose the vibration-absorbing material between the display face and the top face and between the rear face and the top face. According to another specific feature, a fit-coupling structure is adopted between the vibration-absorbing material and each of the top face, the display face, and the rear face. It is thus possible to effectively interpose the vibration-absorbing material between the display face and the top face and between the rear face and the top face. 
     According to another specific feature, the rear face has a rear structure which has an opening and which holds the top face against the display face and a rear lid which covers the opening. It is thus possible to effectively interpose the vibration-absorbing material between the display face and the top face and between the rear face and the top face. 
     According to another specific feature, the vibration source is arranged at the center of the top face. According to another specific feature, the vibration source is arranged in both corner parts of the mobile telephone. According to a further specific feature, when the vibration source is arranged in both corner parts of the mobile telephone, it is arranged in both corner parts with a vibration-absorbing material interposed in between. According to a more specific feature, the vibration-absorbing material is exposed in both corner parts for contact with the ear cartilage. 
     According to another specific feature, there is provided a cover which covers the top face; the cover is formed of a vibration-absorbing material and is continuous with the vibration-absorbing material interposed between the display face and the top face and between the rear face and the top face. It is thus possible to adopt a decent exterior appearance combined with a vibration-absorbing material. 
     According to another feature, a mobile telephone has a top face, a display face having a touch panel function which at its top end reaches near the top face and which is provided on the front face of a casing, a rear face, a pair of vibration sources, and a support having a vibration-absorbing property which is exposed in both corner parts of the mobile telephone and which supports the pair of vibration sources respectively inside the mobile telephone. It is thus possible to obtain satisfactory cartilage conduction while suppressing air-conduction sound. 
     According to a specific feature, the mobile telephone has a vibration-absorbing material which is interposed between the display face and the top face and between the rear face and the top face. It is thus possible to further suppress air-conduction sound. According to a further specific feature, the support which is exposed in both corner parts respectively of the mobile telephone is continuous with the vibration-absorbing material. 
     According to another specific feature, in the mobile telephone, an internal structure of the mobile telephone is supported on at least one of the display face and the rear face, and vibration of at least one of the display face and the rear face is suppressed by the weight of the internal structure. It is thus possible to suppress air-conduction sound. According to a more specific feature, a plurality of internal structures of the mobile telephone are each supported on both the display face and the rear face. 
     &lt;Sixty-First Technical Feature&gt; 
     According to a sixty-first technical feature disclosed herein, a hearing device has a cartilage conduction vibration unit which does not exceed a size that fits in the cavum conchae, a vibration source which is arranged so as to vibrate the entire cartilage conduction vibration unit, and a connection part which connects the cartilage conduction vibration unit to a drive signal source for the vibration source and which has an acoustic impedance different from that of the cartilage conduction vibration unit. It is thus possible to achieve efficient cartilage conduction and to suppress generation of air-conduction sound. According to a specific feature, a through-hole is provided in the cartilage conduction vibration unit to permit outside air-conduction sound to enter the external auditory meatus. 
     According to another specific feature, the connection part is an elastic body. According to another specific feature, the hearing device has an ear hook, the drive signal source is provided in the ear hook, and the connection part connects together the ear hook and the cartilage conduction vibration unit. It is thus possible to suppress conduction of vibration of the cartilage conduction vibration unit to the ear hook. 
     According to another specific feature, there are provided a pair of ear hooks and a pair of cartilage conduction vibration units for the right and left ears respectively, and the drive signal source is provided in one of the pair of the ear hooks. It is thus possible to provide a stereo hearing device with suppressed generation of air-conduction sound. 
     According to a more specific feature, the hearing device has batteries provided in the pair of ear hooks respectively and which by their weights suppress vibration of the ear hooks, and the batteries provided in the pair of ear hooks respectively both supply electric power to the drive signal source provided in one of the pair of ear hooks. It is thus possible to effectively suppress vibration of the ear hooks for both ears. According to a more specific feature, the batteries provided in the pair of ear hooks respectively are connected in series. 
     According to another specific feature, the connection part is a flexible cable. It is thus possible to suppress conduction of vibration via the cable. According to a more specific feature, the flexible cable has such a length as to slacken to prevent conduction of vibration. It is thus possible to suppress conduction of vibration resulting from the cable acting as a string telephone. 
     According to a more specific feature, the hearing device has a pair of cartilage conduction vibration units for the right and left ears respectively, and has an ear hook which is provided for one ear and which has the drive signal source; the pair of cartilage conduction vibration units are both connected to the ear hook provided for one ear, and the cartilage conduction vibration unit provided with no ear hook and the ear hook are connected together by the flexible cable. It is thus possible to suppress conduction of vibration to the ear hook. 
     According to another more specific feature, the hearing device has a pair of cartilage conduction vibration units for the right and left ears respectively, and the pair of cartilage conduction vibration units are both connected to the drive signal source by the flexible cable. It is thus possible to suppress conduction of vibration to the drive signal source. 
     According to another feature, a hearing device has a cartilage conduction vibration unit in which a plurality of piezoelectric bimorph elements having equivalent frequency characteristics are provided as a vibration source. It is thus possible to obtain effective cartilage conduction from a compact cartilage conduction vibration unit. 
     According to another feature, a hearing device has a cartilage conduction vibration unit having a curved periphery and, as a vibration source, a piezoelectric bimorph element which is curved along the periphery. It is thus possible to obtain effective cartilage conduction from a compact cartilage conduction vibration unit. 
     According to another feature, a hearing device has a cartilage conduction vibration unit and, as a vibration source, a piezoelectric bimorph element which extends at the center of the cartilage conduction vibration unit. It is thus possible to obtain effective cartilage conduction from a compact cartilage conduction vibration unit. 
     &lt;Sixty-Second Technical Feature&gt; 
     According to a sixty-second technical feature disclosed herein, a mobile telephone has an electromagnetic vibrating element of which two parts that move relative to each other are supported with an elastic body interposed in between, and vibration for cartilage conduction is extracted from at least one of the two parts. It is thus possible to provide, in the form of an electromagnetic vibrating element, an effective vibration source for mobile telephones. According to a specific feature, the elastic body serves as a cartilage conduction unit that makes contact with the ear cartilage. According to another specific feature, the elastic body is arranged in or near a corner part of a top part of a casing. 
     According to another specific feature, one of the two parts is supported on a casing structure, the elastic body is supported on the casing structure, and the other of the two parts is supported on the elastic body. According to a more specific feature, one of the two parts that is heavier is supported on the elastic body. 
     According to another specific feature, one of the two parts or a part that connects to it serves as a cartilage conduction unit that makes contact with the ear cartilage, and the elastic body is interposed between the two parts. According to another specific feature, the two parts and the elastic body are arranged inside the casing. 
     According to another feature, an earphone has an electromagnetic vibrating element of which two parts that move relative to each other are supported with an elastic body interposed in between, and vibration for cartilage conduction is extracted from at least one of the two parts. It is thus possible to provide, in the form of an electromagnetic vibrating element, an effective vibration source for earphones. According to a specific feature, the elastic body serves as a cartilage conduction unit that makes contact with the ear cartilage. 
     According to another specific feature, the earphone is configured such that vibration that conducts from both two parts to the elastic body is extracted. According to a more specific feature, the two parts are supported on opposite faces of a space inside the elastic body. According to another specific feature, one of the two parts is supported on one of opposite faces of a space inside the cartilage conduction unit with the elastic body in between, and the other of the two parts is supported on the other of the opposite faces. 
     According to another feature, an electromagnetic vibration unit has an electromagnetic vibrating element of which two parts that move relative to each other are supported with an elastic body interposed in between, and vibration for cartilage conduction is extracted from at least one of the two parts. It is thus possible to provide an effective electromagnetic vibration unit for cartilage conduction. 
     According to a specific feature, in the electromagnetic vibration unit, of the two parts, one is supported inside a housing, and the other is supported with the elastic body in between. According to a more specific feature, the elastic body serves as a cartilage conduction unit. 
     According to another specific feature, in the electromagnetic vibration unit, the other part or a part that connects to it serves as a cartilage conduction unit. 
     According to another specific feature, in the electromagnetic vibration unit, the housing is formed of an elastic body. 
     According to another specific feature, in the electromagnetic vibration unit, there is provided a cartilage conduction unit that forms a corner part of a mobile telephone, and vibration is conducted to the cartilage conduction unit from at least one of the two parts. 
     &lt;Sixty-Third Technical Feature&gt; 
     According to a sixty-third technical feature disclosed herein, a handset has a local communication unit which performs wireless communication within a local area, right- and left-ear sound output units which outputs sound received by the local communication unit, and a sound microphone which collects sound to be transmitted from the local communication unit; the right- and left-ear sound output units, when worn on the right and left ears respectively, do not prevent outside sound from entering the right and left external auditory meatus so that the directions from which the outside sound comes can be recognized with both ears as when they are not worn. It is thus possible, in a handset or the like that is used, for example, with a sound output unit worn on one ear and the other ear left open, to eliminate, among others, the drawback of being unable to recognize the direction from which outside sound comes with both ears as when it is not worn. 
     According to another specific feature, the right- and left-ear sound output units have right- and left-ear cartilage conduction units respectively, and the right- and left-ear cartilage conduction units make contact with the right- and left-ear cartilage so as not to prevent outside sound from entering the right and left external auditory meatus. According to another specific feature, the right- and left-ear cartilage conduction units have shapes that fit in the right- and left-ear cava conchae respectively from in front of the face. 
     According to another specific feature, the right- and left-ear cartilage conduction units, when worn, make contact with the tragi respectively. According to another specific feature, the right- and left-ear cartilage conduction units, when worn, make contact with the tragi respectively. According to another specific feature, the right- and left-ear cartilage conduction units have concavities which, when they are worn, make contact with the tragi while preventing the tragi from bending so as to close the entrances of the external auditory meatus respectively. 
     According to another specific feature, the right- and left-ear cartilage conduction units are provided with through-holes away from the concavities so as not to prevent outside sound from entering the right- and left-ear external auditory meatus. According to another specific feature, the right- and left-ear cartilage conduction units are provided with through-holes so as not to prevent outside sound from entering the right- and left-ear external auditory meatus. 
     According to another specific feature, the right- and left-ear sound output units are provided with through-holes so as not to prevent outside sound from entering the right- and left-ear external auditory meatus. According to another specific feature, the right- and left-ear cartilage conduction units are each formed of elastic bodies respectively. 
     According to another specific feature, the right- and left-ear cartilage conduction units have cartilage conduction vibration sources respectively. According to another specific feature, there is provided an arm part which supports the right- and left-ear cartilage conduction units without making contact with the cartilage conduction vibration sources and which have an acoustic impedance different from that of the right- and left-ear cartilage conduction units. 
     According to another specific feature, there are provided right and left outside noise detection microphones which are supported on the arm part. 
     According to another specific feature, the sound collected by the right and left outside noise detection microphones is fed to the right- and left-ear cartilage conduction units respectively so as to cancel external noise inside the right and left external auditory meatus. 
     According to another feature, a handset has a cartilage conduction unit which has a concavity that, when the handset is worn, makes contact with the tragus while preventing the tragus from bending so as to close the entrance of the external auditory meatus. 
     According to another feature, a handset has a right outside noise detection microphone, a left outside noise detection microphone, a right-ear cartilage conduction unit, and a left-ear cartilage conduction unit; the sound collected by the right and left outside noise detection microphones is fed to the right- and left-ear cartilage conduction units respectively so as to cancel external noise inside the right and left external auditory meatus, and of the sound collected by the right and left outside noise detection microphones, a sound component that exhibits a difference between them is not fed to the right- and left-ear cartilage conduction units so as not to be canceled in the right and left external auditory meatus. 
     &lt;Sixty-Fourth Technical Feature&gt; 
     According to a sixty-fourth technical feature disclosed herein, a cycling hearing device has a stereo sound source unit, left and right vibration sources which conduct a stereo sound source from the stereo sound source unit to the left and right ears respectively without closing either of the left and right external auditory meatus, and notifying means that notifies publicly that the left and right external auditory meatus are not closed. It is thus possible to hear sound from the outside world such as vehicle horns with no hindrance and to correctly recognize the direction of the sound from the outside world. It is also possible to avoid needless troubles arising from being misunderstood as violating road traffic law prohibiting riding bicycles with the external auditory meatus closed. 
     According to a specific feature, the left and right vibration sources are cartilage conduction vibration sources respectively. By conducting vibration of the cartilage conduction vibration sources to the ear cartilage, air-conduction sound is generated inside the external auditory meatus, and this air-conduction sound reaches the eardrums so that sound is heard; by exploiting this cartilage conduction mechanism, it is possible to conduct the stereo sound source from the stereo sound source unit to the left and right ears respectively without closing either of the left and right external auditory meatus. 
     According to another specific feature, the cycling hearing device has a helmet part and a chin strap part fitted to the helmet part, the vibration sources are provided in the chin strap part, and the notifying means is an external appearance structure in which the vibration sources conduct vibration to the ear cartilage without closing the external auditory meatus. 
     According to a more specific feature, the vibration sources are provided in the chin strap part so as to conduct vibration to the tragi without closing the external auditory meatus. According to a more specific feature, the vibration sources are provided in the chin strap part so as to conduct vibration to the outside of the cartilage in the bases of the earlobes without closing the external auditory meatus. 
     According to another specific feature, the cycling hearing device has a helmet part, and the notifying means is an indicating means arranged on the helmet part to notify publicly that the left and right external auditory meatus are not closed. According to another specific feature, the cycling hearing device has a sound-transmitting warm ear pad, and the notifying means is an indicating means arranged on the sound-transmitting warm ear pad to notify publicly that the left and right external auditory meatus are not closed. 
     According to another specific feature, a bicycle system has a bicycle which is used in combination with the cycling hearing device, and the notifying means is arranged on the bicycle to notify publicly that the left and right external auditory meatus are not closed. According to a more specific feature, the bicycle has a night lamp, and the notifying means varies the brightness of the night light with a predetermined pattern. According to another specific feature, the notifying means is an indicating means arranged on the bicycle. 
     According to another specific feature, the bicycle has a wheel generator for supplying the night lamp with electric power. According to a more specific feature, the bicycle has charge contacts through which the cycling hearing device is charged, and the wheel generator, when connected to the charge contacts, charges the cycling hearing device through the charge terminals. According to another specific feature, the cycling hearing device is configured as a mobile telephone. 
     According to another more specific feature, the bicycle has a removably-mounted assist rechargeable battery and charge contacts through which the cycling hearing device is charged, and the assist rechargeable battery, when connected to the charge contacts, charges the cycling hearing device through the charge terminals. According to another specific feature, the cycling hearing device is configured as a mobile telephone. 
     According to another feature, a bicycle system includes a mobile telephone and a bicycle having a night lamp, a wheel generator for supplying the night lamp with electric power, and charge contacts, and the wheel generator charges the mobile telephone through the charge contacts. It is thus possible to provide a bicycle system that is useful in bicycle riding. 
     According to another feature, a bicycle system includes a mobile telephone and a bicycle having a removably-mounted assist rechargeable battery for supplying an assist motor with energy, and charge contacts, and the assist rechargeable battery charges the mobile telephone through the charge contacts. It is thus possible to provide a bicycle system that is useful in bicycle riding. It is thus possible to provide a bicycle system that is useful in bicycle riding. 
     &lt;Sixty-Fifth Technical Feature&gt; 
     According to a sixty-fifth technical feature disclosed herein, a pen-type handset is provided that includes: a clip portion; a cartilage-conduction vibration source which conducts vibration to the clip portion; a sound source unit which feeds the cartilage-conduction vibration source with a sound signal in an audible range; a microphone; and a wireless communication unit which receives a sound signal for the sound source unit and which transmits sound from the microphone. Then, a back part of the clip portion can be, as a suitable cartilage conduction unit, put into contact with the tragus, and thus the side of the shape of a slim pen can be used as a satisfactory cartilage conduction unit. 
     According to a specific feature, the pen-type handset further includes: a main body; and a vibration isolating means for isolating conduction of vibration from the clip portion to the main body. According to a more specific feature, the vibration of the cartilage-conduction vibration source is conducted to the clip portion, and between the cartilage-conduction vibration source and the main body, a vibration isolating material is interposed. According to a more specific feature, the clip portion is formed of an elastic body, the cartilage-conduction vibration source is provided in the clip portion, and the clip portion is supported on the main body such that the cartilage-conduction vibration source does not make direct contact with the main body. According to another more specific feature, the cartilage-conduction vibration source is supported on the clip portion, and the clip portion is supported on the main body via the vibration isolating material. 
     According to another specific feature, there is provided a vibration conduction unit for conducting the vibration of the cartilage-conduction vibration source to the main body; when the clip portion is closed, the vibration conduction unit does not conduct the vibration of the cartilage-conduction vibration source to the main body and, when the clip portion is open, the vibration conduction unit conducts the vibration of the cartilage-conduction vibration source to the main body. 
     According to another specific feature, the pen-type handset further includes an incoming-call display unit; when the clip portion is closed, the incoming-call display unit is allowed to operate and, when the clip portion is open, the incoming-call display unit is prohibited from operating. 
     According to another specific feature, the pen-type handset further includes an operation unit; when the clip portion is closed, operation on the operation unit is validated and, when the clip portion is open, operation on the operation unit is invalidated. 
     According to another specific feature, the pen-type handset responds to an incoming call on detecting the clip portion shifting from an open state to a closed state. 
     According to another specific feature, the pen-type handset further includes a control unit which feeds the cartilage-conduction vibration source with a signal in a sense-of-vibration range for incoming call notification. 
     According to another specific feature, the pen-type handset further includes a storage unit; during a search for call origination, the handset stores data on a communication partner in the storage unit from the outside, and after use of the data, the handset erases the data on the communication partner from the storage unit. 
     According to another specific feature, the pen-type handset, when it is used, performs voiceprint recognition. 
     According to another specific feature, the pen-type handset has a cross-sectional diameter of 1.5 cm or less. This feature relies on the mechanism of cartilage conduction which allows sound to be heard through contact with a cartilage over a small area. 
     &lt;Sixty-Sixth Technical Feature&gt; 
     According to a sixty-sixth technical feature disclosed herein, stereo earphones are provided that include a pair of each of the following: a cartilage conduction unit having a through-hole for introducing outside sound into the ear canal and held in a space between the inside of the tragus and the antihelix; a vibration source which conducts vibration to the cartilage conduction unit; an air-conduction sound source disposed outside the through-hole; and a sound conduction pipe for introducing the air-conduction sound generated by the air-conduction sound source into the through-hole. It is thus possible to allow outside sound to be heard, and to more easily provide stereo earphones with better sound quality. 
     According to a specific feature, the cartilage conduction unit has a directivity producing structure which makes the air-conduction sound directional toward the ear canal entrance. According to a more specific feature, the sound conduction pipe introduces the air-conduction sound into the directivity producing structure. According to another specific feature, the directivity producing structure is provided concentrically inside the through-hole. 
     According to another specific feature, the sound conduction pipe has an air-conduction sound discharge port which makes the air-conduction sound directional toward the ear canal entrance. According to a more specific feature, the sound conduction pipe is so disposed as not to hinder outside sound from being introduced through the through-hole into the ear canal. 
     According to another specific feature, there is provided a hollow sheath portion which is connected to the cartilage conduction unit; the vibration source is a piezoelectric bimorph element which is supported on the cartilage conduction unit inside the hollow sheath portion without touching its inner wall and which vibrates freely inside the sheath portion, and the sound conduction pipe doubles as the hollow sheath portion and is open inside the through-hole. According to a specific feature, the air-conduction sound source generates the air-conduction sound inside the hollow sheath portion. According to a more specific feature, the air-conduction sound source is an air-conduction speaker provided separately from the vibration source. According to a more specific feature, the vibration source and the air-conduction speaker are controlled independently of each other. According to a more specific feature, the vibration source is controlled to mainly cover mid- and low-range sound by exploiting the frequency characteristics of cartilage conduction. 
     According to another specific feature, the air-conduction sound source is a vibration plate that is supported on the piezoelectric bimorph element which vibrates freely inside the hollow sheath portion. 
     According to another specific feature, the vibration source is disposed inside the cartilage conduction unit. According to a more specific feature, the vibration source is a piezoelectric bimorph element. According to another more specific feature, the vibration source is an electromagnetic vibrator. 
     According to another specific feature, the sound conduction pipe has a bent portion in the shape of an ear hook that extends from the incisura anterior via a top part of the auricle to the air-conduction sound source at a rear part of the auricle. According to another specific feature, the sound conduction pipe has a bent portion in the shape of an earpiece that extends from the incisura anterior via a bottom part of the auricle to the air-conduction sound source at a rear part of the auricle. 
     According to another specific feature, the cartilage conduction unit is formed of an elastic body. According to a more specific feature, the sound conduction pipe is formed of a material with an acoustic impedance different from that of the cartilage conduction unit. 
     According to another feature, a stereo headset is provided that includes a pair of each of the following: a cartilage conduction unit having a through-hole for introducing outside sound into the ear canal and held in a space between the inside of the tragus and the antihelix; a vibration source which conducts vibration to the cartilage conduction unit; an air-conduction sound source disposed outside the through-hole; a sound conduction pipe for introducing the air-conduction sound generated by the air-conduction sound source into the through-hole; an acoustic processing unit; a power supply unit, and a wireless communication unit. 
     According to a specific feature of the present invention, the sound conduction pipe has a bent portion in the shape of an ear hook that extends from the incisura anterior via a top part of the auricle to the air-conduction sound source at a rear part of the auricle, and at least the power supply unit is disposed at a rear part of the auricle. According to another specific feature, the sound conduction pipe has a bent portion in the shape of an earpiece that extends from the incisura anterior via a bottom part of the auricle to the air-conduction sound source at a rear part of the auricle, and at least the power supply unit is disposed at a rear part of the auricle. According to another specific feature, the cartilage conduction unit is formed of an elastic body. According to a more specific feature, the sound conduction pipe is formed of a material with an acoustic impedance different from that of the cartilage conduction unit. 
     &lt;Sixty-Seventh Technical Feature&gt; 
     According to a sixty-seventh technical feature disclosed herein, a mobile telephone is provided that includes: a main body having in a top part of it a module replacement slot; and a cartilage conduction module insertable in the module replacement slot to be put into contact with an ear cartilage. It is thus possible to build a cartilage conduction mobile telephone simply by replacing modules. 
     According to a specific feature, the mobile telephone permits an air-conduction speaker module including an air-conduction speaker to be inserted in the module replacement slot. According to a more specific feature, the cartilage conduction unit can vibrate at least both end parts of the cartilage conduction module, and the air-conduction speaker is disposed in a middle part of the air-conduction speaker module. It is thus possible, irrespective of whether the cartilage conduction module or the air-conduction speaker module is inserted in the module replacement slot, to use the mobile telephone with either of the right and left ears. On the other hand, according to another specific feature, the cartilage conduction unit can vibrate the entire cartilage conduction module. 
     According to another specific feature, the mobile telephone includes a means for preventing the cartilage conduction module from clattering inside the module replacement slot when the cartilage conduction unit vibrates. With this, even when a small gap is provided to help the cartilage conduction module slide into the module replacement slot, it is possible to prevent the cartilage conduction module from clattering when vibrated. 
     According to another specific feature, the cartilage conduction module can be inserted in the module replacement slot reversibly or interchangeably for either of the right and left ears. According to a more specific feature, either the cartilage conduction module is inserted in the module replacement slot with or without the reversal of its direction, or a cartilage conduction module for use in right arrangement and a cartilage conduction module for use in left arrangement are prepared so that one of them is chosen to be inserted in the module replacement slot. With this configuration, a cartilage conduction unit has only to be provided in one side of the cartilage conduction module. 
     According to another feature, a mobile telephone-compatible module is provided that is insertable, in a mobile telephone having in a top part of it a module replacement slot, in the module replacement slot and that includes a cartilage conduction unit for contact with an ear cartilage. It is thus possible to build a cartilage conduction mobile telephone more easily than building an entire cartilage conduction mobile telephone from scratch. 
     According to a specific feature, the part that makes contact with the module replacement slot is an elastic body. With this, even when a small gap is provided to permit the cartilage conduction module to be slid into the module replacement slot, it is possible to prevent the cartilage conduction module from clattering when vibrated. According to another specific feature, the cartilage conduction unit is formed of an elastic body, and the cartilage conduction module includes a vibration source that conducts vibration to the cartilage conduction unit without making contact with any other part. According to another specific feature, the cartilage conduction unit is formed of a rigid body, and the cartilage conduction module includes a vibration source that conducts vibration to the cartilage conduction unit without making contact with any other part. According to a more specific feature, between the cartilage conduction unit and other parts, an elastic body is interposed. 
     According to another specific feature, the mobile telephone-compatible module includes a videophone inner camera. According to a more specific feature, the mobile telephone-compatible module includes vibration conduction preventing means for preventing conduction of vibration from the cartilage conduction unit to the videophone inner camera. According to a still more specific feature, a difference in acoustic impedance is produced between the cartilage conduction unit and the videophone inner camera. According to another still more specific feature, a videophone air-conduction speaker is disposed between the cartilage conduction unit and the videophone inner camera. According to another still more specific feature, the cartilage conduction unit and the videophone inner camera are disposed away from each other. According to another still more specific feature, when the videophone inner camera is used, vibration of the cartilage conduction unit is prohibited. 
     According to another specific feature, the mobile telephone-compatible module can be inserted in the module replacement slot with or without reversal of its direction so as to be reversible for either of the right and left ears. With this construction, a cartilage conduction unit has only to be provided in one side of the cartilage conduction module. 
     According to a more specific feature, the mobile telephone-compatible module includes a right contact unit used for insertion in the right ear and a left contact unit used for insertion in the left ear. Even when the mobile telephone main body-side contact unit is disposed lopsided to one side, insertion is possible for either of the right and left ears. According to a more specific feature, the mobile telephone-compatible module includes a protection unit against improper connection of either of the right and left contacts to the mobile telephone main body-side contact unit provided in the module replacement slot. 
     According to another specific feature, in a case where a videophone inner camera is provided, the image on the videophone inner camera is inverted upside down between during insertion in the right ear and during insertion in the left ear. This helps eliminate inconveniences arising during a videophone call with the mobile telephone-compatible module inserted with or without reversal of its direction in the module replacement slot. 
     &lt;Sixty-Eighth Technical Feature&gt; 
     According to a sixty-eighth technical feature disclosed herein, a mobile telephone is provided that includes: a sound signal generation unit which generates a sound signal; and an acoustic processing switching unit which, when a hearing aid is used, subjects the sound signal to acoustic processing so switched as to suit the hearing aid. The user can then conduct a call on the mobile telephone with satisfactory acoustics even while wearing a hearing aid. According to a specific feature, the acoustic processing switching unit switches the acoustic processing between when the sound signal is heard directly and when it is heard via the hearing aid. 
     According to another specific feature, in a cartilage conduction mobile telephone including a cartilage conduction unit which is vibrated with a sound signal having undergone acoustic processing by the acoustic processing switching unit and which makes contact with an ear cartilage, the acoustic processing switching unit switches the acoustic processing according to whether the cartilage conduction unit is in direct contact with the ear cartilage or is in contact with a hearing aid worn on the ear. Thus, when the user puts the cartilage conduction unit into contact with the hearing aid while still wearing it, the vibration of the cartilage conduction unit conducts to the hearing aid, and the vibration then conducts to the ear cartilage in which the hearing aid is in contact, so that air-conduction sound from the ear cartilage is generated inside the ear canal, and this air-conduction sound reaches the eardrum, allowing sound to be heard. In this way, even with the hearing aid kept worn, the mechanism of sound conduction after vibration has conducted to the ear cartilage is the same as when the vibration of the cartilage conduction unit is conducted directly to the ear cartilage, and this allows a call with satisfactory cartilage conduction. Moreover, in this case, the hearing aid functions as a vibration conduction unit that conducts vibration from the mobile telephone to the ear cartilage, and thus it is then preferable to turn off at least either the microphone or the speaker of the hearing aid to stop its inherent function. The hearing aid performs equalization that suits the user&#39;s hearing characteristics; even when the inherent function of the hearing aid is stopped as mentioned above, the situation can be coped with by switching the acoustic processing such that it suits the hearing aid. 
     According to another specific feature, the mobile telephone includes a setting unit which performs previous customization setting on acoustic processing data for the acoustic processing switching unit mentioned above such that it suits the hearing aid. More specifically, the setting unit stores the acoustic processing data with different customization settings for a plurality of different hearing aids respectively. According to a still more specific feature, the mobile telephone includes an NFC tag reader, and selects from the acoustic processing data stored in the setting unit by reading information from an NFC tag provided in the hearing aid. 
     According to another specific feature, the mobile telephone includes a microphone, and the acoustic processing switching unit switches the sound signal during use of the hearing aid to one that suits it by inverting the waveform of the sound signal collected by the microphone and then mixing it. Since the hearing aid closes the ear canal entrance, it is used in a closed ear canal state. Thus, by inverting the waveform of the sound signal collected by the microphone and then mixing it, the user&#39;s live voice conducting from the cranium is canceled inside the ear canal, and this alleviates the feeling of strangeness to the user&#39;s own voice. 
     According to another feature, a mobile telephone is provided that includes a sound signal generation unit which generates a sound signal and a setting unit which performs customization setting for a hearing aid. With this, even when no customization to adapt to the user&#39;s hearing characteristics is performed on the hearing aid, customization can be preformed on the mobile telephone. According to a specific feature, the setting unit can, by making settings corresponding to the customization setting on the hearing aid, perform customization corresponding to it even when customization is not performed on the hearing aid. According to another specific feature, the setting unit stores acoustic processing data with different customization settings for a plurality of different hearing aids respectively. 
     According to another feature, a hearing aid is provided that includes a microphone and a speaker and that automatically turns off at least either the microphone or the speaker when a mobile telephone makes contact with it and vibration for cartilage conduction is conducted to it. The hearing aid, when a mobile telephone makes contact with it and vibration for cartilage conduction is conducted to it, functions as a vibration conduction unit that conducts vibration from the mobile telephone to an ear cartilage. Accordingly, at least either the microphone or the speaker of the hearing aid is turned off so that the inherent function of the hearing aid is stopped, and this helps prevent the conducted vibration from adversely affecting the inherent function of the hearing aid. According to a specific feature, when no vibration for cartilage conduction is conducted, the microphone and the speaker are turned on automatically. According to a more specific feature, for a predetermined period after vibration for cartilage conduction ceases to be conducted, the microphone and the speaker are suspended from being turned on automatically. 
     According to another feature, a hearing aid is provided that includes a microphone, a speaker, and an NFC tag. It is then possible to extract and read out data from the hearing aid with an NFC tag reader, and this allows various forms of coordination between the hearing aid and the outside. According to a specific feature, the hearing aid includes a customization setting unit which performs customization that suits a user, and the NFC tag stores a customization ID that identifies settings made by the customization setting unit. 
     According to another feature, a hearing aid is provided that includes a microphone, a speaker, and an elastic-material coating in a part of the hearing aid in contact with a mobile telephone. This helps prevent the part in contact with the mobile telephone from clattering due to vibration. 
     According to another feature, a hearing aid is provided that includes a microphone, a speaker, and a casing that has, from a part making contact with a mobile telephone to a part making contact with an ear cartilage, an acoustically integral structure for conducting vibration. With this, vibration conducted through contact with the mobile telephone efficiently conducts to the ear cartilage, and satisfactory cartilage conduction is obtained. According to a specific feature, the hearing aid is configured as an ear-hole hearing aid that has, from a part making contact with the mobile telephone to a part making contact with the ear cartilage, an acoustically integral structure for conducting vibration. According to another specific feature, the hearing aid is configured as an ear-hook hearing aid having an ear hook part and an ear-hole insertion part, and the ear-hole insertion part has, from a part making contact with the mobile telephone to a part making contact with the ear cartilage, an acoustically integral structure for conducting vibration. 
     According to another specific feature, a hearing aid is used in combination with a mobile telephone having features as described above. A mobile telephone is used in combination with a hearing aid having features as described above. Thus, satisfactory coordination between a mobile telephone and a hearing aid is achieved. 
     INDUSTRIAL APPLICABILITY 
     The various inventions disclosed in the present specification can be applied to incoming-talk devices such as mobile telephones, telephone handsets and other audio output devices, handsets (talk-receiver/transmitters) or talk-receivers for mobile telephones, cartilage conduction vibration source devices or cartilage conduction source vibration devices for a mobile telephone, mobile telephone soft covers, headsets, soft covers and other mobile telephone auxiliary devices, and headsets used as mobile telephones, as well as headsets used as mobile telephones and other outgoing talk/incoming talk devices; and also mobile telephones, mobile music terminals, and other sound signal output devices, and listening devices, outgoing talk/incoming talk devices, headsets for receiving sound signals of these sound signal output devices, stereo earphones or earphones, wrist watch-type handsets, name plates and non-contact IC cards, mobile telephones, earphones, electromagnetic vibration units to serve as cartilage conduction vibration sources for these, handsets useful for local communication and the like, cycling hearing devices and bicycle systems, pen-type handsets in general, pen-type handsets used in combination with mobile telephones in particular, stereo earphones and stereo headsets, mobile telephones and mobile telephone-compatible modules, or coordination between mobile telephones and hearing aids. 
     LIST OF REFERENCE SIGNS 
     
         
         
           
               83024 ,  84024  clip portion 
               83025 ,  84025  cartilage-conduction vibration source 
               83040  sound source unit 
               35023  microphone 
               6546  wireless communication unit 
               83024 ,  84013  vibration isolating means 
               83024 ,  84013  vibration isolating material 
               83024  elastic body clip portion 
               83027 ,  84027  vibration conduction unit 
               83005  incoming-call display unit 
               83009  operation unit 
               85024   a ,  85024   c ,  86024   a ,  86024   c ,  87024   a  through-hole 
               85024 ,  86024 ,  87024 ,  89024  cartilage conduction unit 
               84025 ,  88025 ,  89025  vibration source 
               85027 ,  88027  air-conduction sound source 
               85024   b ,  85024   y ,  86024   y ,  87024   b ,  87024   y ,  88024   b ,  89024   b ,  89024   y  sound conduction pipe 
               85024   c ,  86024   z ,  86000 ,  87000  directivity producing structure 
               85024   b ,  87024   b ,  88024   b ,  89024   b  hollow sheath portion 
               93001   a  module replacement slot 
               93001  main body 
               93024 ,  93026 ,  94024 ,  95024 ,  95026 ,  96024 ,  97024  cartilage conduction unit 
               93027 ,  94027 ,  95027   a ,  95027   b ,  96027 ,  97027  cartilage conduction module 
               93013   a  air-conduction speaker 
               93013  air-conduction speaker module 
               93024 ,  93026 ,  94024 ,  95024 ,  95026 ,  96065  elastic body 
               93025   a ,  93025   b ,  94025 ,  97025  vibration source 
               93017 ,  96017  videophone inner camera 
               94027   a  right contact unit 
               94027   b  left contact unit 
               93001   b  mobile telephone main body-side contact unit 
               94070  protection unit 
               98001  mobile telephone 
               98081 ,  99081  hearing aid 
               45  sound generation unit 
               236 ,  98038 ,  57039  acoustic processing switching unit 
               98024 ,  98025 ,  98026  cartilage conduction unit 
               98089  setting unit 
               98046  NFC tag reader 
               98037  NFC tag 
               223  mobile telephone microphone 
               9  mobile telephone manual operation unit 
               98022  hearing aid microphone 
               98027  hearing aid speaker 
               98081   b  elastic-material coating 
               98081   a ,  99081   b  acoustically integral structure 
               98009  hearing aid manual operation unit 
               98090  customization setting unit