Abstract:
A mobile terminal apparatus includes a first housing having a first surface and a second surface opposite to the first surface, the first surface having a first opening extending therethrough; a first microphone disposed in the first housing adjacent to the first opening; a second housing having a slide surface and an opposite surface opposite to the slide surface, the slide surface being slidable over the second surface of the first housing, the second housing overlapping a portion of the first housing including a position at which the first microphone is disposed when the second housing overlaps the first housing in a minimum area, the opposite surface having a second opening extending therethrough in a part thereof corresponding to the minimum area; and a second microphone disposed in the second housing adjacent to the second opening.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2010-72092 filed on Mar. 26, 2010, the entire contents of which are incorporated herein by reference. 
       FIELD 
       [0002]    The embodiments discussed herein are relates to a mobile terminal apparatus. 
       BACKGROUND 
       [0003]    Some mobile terminal apparatuses, such as mobile phones, have a fixed housing, on which operation keys and the like are disposed, and a movable housing, on which a liquid crystal display and the like are disposed, and the movable housing is slidably connected to the fixed housing. The size of such a slide-type mobile terminal apparatus is the smallest when the mobile terminal apparatus is in a closed state in which the fixed housing and the movable housing overlap in the maximum overlapping area. When not in use, a user carries a compact mobile terminal apparatus in the closed state. The mobile terminal apparatus provides a user with various functions when the slide-type mobile terminal apparatus is in an open state in which the fixed housing and the movable housing overlap in the minimum overlapping area. For example, a user causes the mobile terminal apparatus to be in the open state by sliding the movable housing relative to the fixed housing, and then uses the mobile terminal apparatus as a telephone. 
         [0004]    The functionality of mobile terminal apparatuses has been increased in recent years, and a single terminal usually has multiple functions. For example, a mobile phone has a one-segment broadcasting function or a noise reduction function that reduces ambient noise that interferes with a telephone conversation by using two microphones. 
         [0005]    Referring to  FIGS. 9 to 13 , a slide-type mobile phone including two microphones will be described.  FIG. 9  is a perspective view of the front surface side of the slide-type mobile phone. As illustrated in  FIG. 9 , a mobile phone  200  includes a movable housing  210  and a fixed housing  220 . The movable housing  210  and the fixed housing  220  are slidably connected to each other.  FIG. 9  illustrates an open state in which the movable housing  210  has been slid relative to the fixed housing  220 . 
         [0006]    A liquid crystal display and the like are disposed in the movable housing  210 . Operation keys and the like are disposed in the fixed housing  220 . Hereinafter, a surface of the fixed housing  220  on which the operation keys are disposed as illustrated in  FIG. 9  will be referred to as the “front surface”, and a surface of the fixed housing  220  opposite to the surface on which the operation keys are disposed will be referred to as the “back surface”. The fixed housing  220  includes a front case  221 , which is positioned on the operation keys side, and a back case  222 , which is positioned on the back surface side. An opening  223  is formed in the front case  221 . The opening  223  is a through-hole that extends to a microphone disposed on the front surface side in the fixed housing  220 . 
         [0007]      FIG. 10  is an enlarged view of a region surrounding the microphone that is disposed on the front surface side in the fixed housing  220 . As illustrated in  FIG. 10 , a main circuit board  224  is disposed in the fixed housing  220 . A microphone  225  is disposed on the main circuit board  224  at a position close to the opening  223 . For example, the microphone  225  is disposed on the main circuit board  224  at a position corresponding to the opening  223 . The voice of a user enters the fixed housing  220  through the opening  223  and is picked up by the microphone  225  that is disposed on the front surface side. 
         [0008]      FIG. 11  is a perspective view of the back surface side of the slide-type mobile phone  200 . As illustrated in  FIG. 11 , a battery cover case  226 , having an opening  227  formed therein, is attached to the back case  222  of the fixed housing  220 . The opening  227  is a through-hole that extends to a microphone disposed on the back surface side in the fixed housing  220 . 
         [0009]      FIG. 12  is an enlarged view of a region surrounding the microphone that is disposed on the back surface side in the fixed housing  220 . As illustrated in  FIG. 12 , a microphone  228  is disposed on the main circuit board  224  in the fixed housing  220  at a position close to the opening  227 . The ambient noise around the mobile phone  200  enters the fixed housing  220  through the opening  227 , and is picked up by the microphone  228  that is disposed on the back surface side. The mobile phone  200  removes the ambient noise that is picked up by the microphone  228  from the voice that is picked up by the microphone  225 , and thereby reduces the ambient noise that interferes with a telephone conversation. 
         [0010]      FIG. 13  is a schematic sectional view taken along line I-I of  FIG. 9 . As illustrated in  FIG. 13 , the microphone  225  on the front surface side and the microphone  228  on the back surface side are disposed close to each other. For example, the microphone  225  and the microphone  228  are disposed at substantially the same position with respect to the direction perpendicular to the main circuit board  224 , so that the microphone  228  picks up the ambient noise around the microphone  225 . Therefore, the mobile phone  200  reduces the ambient noise that interferes with a telephone conversation. 
         [0011]    Japanese Laid-open Patent Publication No. 2003-338769 describes a mobile wireless terminal device in which a microphone is disposed in a front case. Japanese Laid-open Patent Publication No. 2006-345246 describes a slide-type mobile phone that includes a plurality of microphones. 
         [0012]    However, the technologies described in these Publications have a problem in that the sound pickup performance may be impaired. To be specific, when a user uses the mobile phone  200  illustrated in  FIG. 9  as a telephone, the opening  223  and the opening  227  may be covered by a user&#39;s hand. If the opening  223  and the opening  227  are covered, the microphone  225  may not sufficiently pick up the voice of the user. The microphone  228  may not sufficiently pick up the ambient noise. If the voice and the ambient noise are not sufficiently picked up, a high quality voice may not be transmitted to the party on the other end or the ambient noise may not be sufficiently reduced. 
         [0013]    A slide-type mobile terminal apparatus is in the open state when a user uses the terminal as a telephone. Therefore, the position at which a microphone is to be placed in the slide-type mobile terminal apparatus is limited to a certain extent. In particular, for a slide-type mobile terminal apparatus that includes two microphones, the two microphones are disposed close to each other, so that the positions of the microphones are further limited. In a slide-type mobile terminal apparatus including two microphones, the microphones are disposed, for example, at positions illustrated in  FIG. 9 . As a result, the sound pickup performance may be impaired if the opening is covered. 
       SUMMARY 
       [0014]    According to an aspect of the embodiment, a mobile terminal apparatus includes a first housing having a first surface and a second surface opposite to the first surface, the first surface having a first opening extending therethrough; a first microphone disposed in the first housing adjacent to the first opening; a second housing having a slide surface and an opposite surface opposite to the slide surface, the slide surface being slidable over the second surface of the first housing, the second housing overlapping a portion of the first housing including the position at which the first microphone is disposed when the second housing overlaps the first housing in a minimum area, the opposite surface having a second opening extending therethrough in a part thereof corresponding to the minimum area; and a second microphone disposed in the second housing adjacent to the second opening. 
         [0015]    The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims. 
         [0016]    It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, as claimed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  is a perspective view of a mobile phone according to the present embodiment, which is viewed from the front surface side; 
           [0018]      FIG. 2  is a perspective view of the mobile phone according to the present embodiment, which is viewed from the back surface side; 
           [0019]      FIG. 3  is an enlarged view of a part of the back case, viewed in the direction of arrow A in  FIG. 1 ; 
           [0020]      FIG. 4  is an enlarged view of a part of the front case; 
           [0021]      FIG. 5  is an enlarged view of the flexible flat cable; 
           [0022]      FIG. 6  is an enlarged view of the flexible flat cable; 
           [0023]      FIG. 7  is an enlarged view of a region surrounding the microphone disposed on the back surface side in the fixed housing; 
           [0024]      FIG. 8  is a schematic sectional view of  FIG. 1  taken along line II-II; 
           [0025]      FIG. 9  is a perspective view of the front surface side of the slide-type mobile phone; 
           [0026]      FIG. 10  is an enlarged view of a region surrounding the microphone that is disposed on the front surface side in the fixed housing; 
           [0027]      FIG. 11  is a perspective view of the back surface side of the slide-type mobile phone; 
           [0028]      FIG. 12  is an enlarged view of a region surrounding the microphone that is disposed on the back surface side in the fixed housing; and 
           [0029]      FIG. 13  is a schematic sectional view taken along line I-I of  FIG. 9 . 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0030]    Hereinafter, a mobile terminal apparatus according to a present embodiment will be described with reference to the drawings. The mobile terminal apparatus according to the present embodiment is for example, a mobile phone. However, the mobile terminal apparatus may be a personal digital assistant (PDA) or the like. 
         [0031]    The mobile phone according to the present embodiment includes two microphones. One microphone is disposed in a movable housing, and the other microphone is disposed in a fixed housing. Hereinafter, the disposition of the microphones and the like will be described. Referring to  FIG. 1 , an external view of the mobile phone according to the present embodiment will be described.  FIG. 1  is a perspective view of a mobile phone  100  according to the present embodiment, which is viewed from the front surface side. As illustrated in  FIG. 1 , the mobile phone  100  according to the present embodiment includes a movable housing  110  and a fixed housing  120 . 
         [0032]    In the present embodiment, a surface of the movable housing  110  on which a liquid crystal display is disposed may be referred to as the “front surface”. In the present embodiment, a surface of the movable housing  110  that is opposite to the surface on which the liquid crystal display is disposed may be referred to as the “back surface”. In the present embodiment, a surface of the fixed housing  120  on which operation keys are disposed may be referred to as the “front surface”. In the present embodiment, a surface of the fixed housing  120  that is opposite to the surface on which the operation keys are disposed may be referred to as the “back surface”. 
         [0033]    The movable housing  110  and the fixed housing  120  are movably connected to each other by a connection portion (not illustrated). The connection portion is a slide mechanism that slidably connects the movable housing  110  and the fixed housing  120  to each other.  FIG. 1  illustrates an open state in which the movable housing  110  has been slid and the movable housing  110  and the fixed housing  120  overlap in the minimum overlapping area. When it is not used, the slide-type mobile phone  100  is in a closed state in which the movable housing  110  and the fixed housing  120  substantially completely overlap. When a user operates the operation keys disposed on the fixed housing  120 , the user slides the movable housing  110  relative to the fixed housing  120  in the longitudinal direction, and the mobile phone  100  is in an open state. 
         [0034]    As illustrated in  FIG. 1 , the movable housing  110  includes a front case  111  and a back case  112 . The front case  111  is on an outer side of the mobile phone  100  in the closed state. The back case  112  is on an inner side of the mobile phone  100  in the closed state. 
         [0035]    The front case  111  includes a receiver  113 , which receives a telephone voice, and a liquid crystal display  114 , which displays various information. An opening  115  extends through the front case  111 . The opening  115  is a through-hole that extends to a microphone (not illustrated) that is disposed on the front surface side in the movable housing  110 . In the example illustrated in  FIG. 1 , the opening  115  is formed in the front case  111  of the movable housing  110  at a position below the liquid crystal display  114 . In other words, the opening  115  is located at a position close to the center of the mobile phone  100  in the longitudinal direction when the mobile phone  100  is in the open state. In the example illustrated in  FIG. 1 , the opening  115  is located at a position close to the center of the width D 1  of the movable housing  110  in lateral direction. 
         [0036]    In the mobile phone  100  according to the present embodiment, the opening  115  is formed at a position below the liquid crystal display  114 . Therefore, when a user uses the mobile phone  100  as a telephone, a user is unlikely to cover the opening  115 . This is because, when a user uses the mobile phone  100  as a telephone, the user does not usually hold a part of the mobile phone  100  that is close to the center of the mobile phone  100  in the longitudinal direction. In the mobile phone  100  according to the present embodiment, the opening  115  is located close to the center of the width D 1  of the movable housing  110  in the lateral direction. When a user uses the mobile phone  100  as a telephone, the user does not hold a part of the mobile phone  100  that is close to the center in the longitudinal direction and close to the center in the lateral direction. Therefore, with the mobile phone  100  according to the present embodiment, the opening  115  is prevented from being covered by a user. 
         [0037]    When the fixed housing  120  and the movable housing  110  overlap in the minimum area H 10 , the fixed housing  120  overlaps a part of the movable housing  110  in which the opening  115  is formed. In other words, regardless of whether the mobile phone  100  is in the open state or in the closed state, the fixed housing  120  overlaps the opening  115  formed in the movable housing  110 . 
         [0038]    As illustrated in  FIG. 1 , the fixed housing  120  includes a front case  121  and a back case  122 . The front case  121  is on an inner side when the mobile phone  100  is in the closed state. The back case  122  is on an outer side when the mobile phone  100  is in the closed state. A keypad  123  is disposed on the front case  121 . The keypad  123  includes operation keys, such as a multifunction key, an enter key, a dial key, and numeric keys. 
         [0039]    Referring to  FIG. 2 , an external view of the back surface side of the mobile phone  100  according to the present embodiment will be described.  FIG. 2  is a perspective view of the mobile phone  100  according to the present embodiment, which is viewed from the back surface side. As illustrated in  FIG. 2 , an opening  124  extends through the back case  122  of the fixed housing  120 . 
         [0040]    The opening  124  is a through-hole that extends to a microphone (not illustrated) that is disposed on the back surface side in the fixed housing  120 . The opening  124  is formed in the back case  122  at a position in the minimum area H 10 , which is the smallest area in which the movable housing  110  and the fixed housing  120  overlap. In the example illustrated in  FIG. 2 , the opening  124  is located close to the center of the width D 1  of the fixed housing  120  in the lateral direction. 
         [0041]    In the mobile phone  100  according to the present embodiment, the opening  124  is located close to the center of the fixed housing  120 . A user is unlikely to cover the opening  124  when the mobile phone  100  is used as a telephone. 
         [0042]    Referring to  FIGS. 3 and 4 , a microphone that is disposed in the movable housing  110  will be described.  FIGS. 3 and 4  are enlarged views of a region surrounding the microphone that is disposed on the front surface side in the movable housing  110 .  FIG. 3  is an enlarged view of a part of the back case  112 , viewed in the direction of arrow A in  FIG. 1 .  FIG. 4  is an enlarged view of a part of the front case  111 , viewed in the direction of arrow B in  FIG. 1 . 
         [0043]    As illustrated in  FIG. 3 , the liquid crystal display  114 , a flexible flat cable  130 , and other components are disposed in the back case  112  of the movable housing  110 . The liquid crystal display  114  is, for example, a liquid crystal display (LCD) module, and the liquid crystal display  114  displays various information. The liquid crystal display  114  may be used as a touch panel in cooperation with a touch pad (not illustrated) and function as an input device. 
         [0044]    The flexible flat cable  130  is integrated with a frequency modulation (FM) transmitter antenna  131 . The flexible flat cable  130  is connected to the electrical system (not illustrated) in the movable housing  110 . That is, the flexible flat cable  130  electrically connects the FM transmitter antenna  131  to the electrical system (not illustrated) in the movable housing  110 . The flexible flat cable  130  is fastened to the back case  112  with a fastener  132   a.    
         [0045]    In the movable housing  110  of the present embodiment, a microphone  116  is disposed close to the opening  115  in the front case  111 . To be specific, as illustrated in  FIG. 3 , the microphone  116  is disposed on the flexible flat cable  130 . For example, the microphone  116  is disposed on the flexible flat cable  130  at a position corresponding to the opening  115 . The flexible flat cable  130  electrically connects the microphone  116  to the electrical system (not illustrated) in the movable housing  110 . The voice of a user enters the movable housing  110  through the opening  115  and is picked up by the microphone  116 , which is disposed on the front surface side in the movable housing  110 . 
         [0046]    Referring to  FIG. 4 , how the flexible flat cable  130  illustrated in  FIG. 3  is disposed in the front case  111  will be described. As illustrated in  FIG. 4 , a flexible printed circuit (FPC) connector  117 , an LCD flexible flat cable  118 , a touch panel flexible flat cable  119 , and other components are disposed in the front case  111 . 
         [0047]    The FPC connector  117  is a connector to which the flexible flat cable  130  is connected. The FPC connector  117  electrically connects the FM transmitter antenna  131  and the microphone  116 , which are disposed in/on the flexible flat cable  130 , to a circuit board and the like. The LCD flexible flat cable  118  electrically connects the LCD module of the liquid crystal display  114  to the circuit board and the like. The touch panel flexible flat cable  119  electrically connects the touch pad (not illustrated) to the circuit board and the like. 
         [0048]    Referring to  FIGS. 5 and 6 , the flexible flat cable  130  will be described.  FIGS. 5 and 6  are enlarged views of the flexible flat cable  130 . As illustrated in  FIGS. 5 and 6 , a cable hole  132   b  is formed in the flexible flat cable  130 . The fastener  132   a , which is illustrated in  FIG. 3 , is inserted through the cable hole  132   b . The fastener  132   a , which is illustrated in  FIG. 3 , is inserted through the cable hole  132   b , and fastens the flexible flat cable  130  to the back case  112 . 
         [0049]    As illustrated in  FIGS. 5 and 6 , the flexible flat cable  130  includes the FM transmitter antenna  131  at one end thereof and an FPC connector plug  134  at the other end thereof. The FPC connector plug  134  is plugged into the FPC connector  117  illustrated in  FIG. 4 . When the FPC connector plug  134  is plugged into the FPC connector  117 , the flexible flat cable  130  is connected to the electrical system (not illustrated) in the movable housing  110 . The flexible flat cable  130  electrically connects the FM transmitter antenna  131  and the microphone  116  to the electrical system (not illustrated) in the movable housing  110 . 
         [0050]    In the mobile phone  100  according to the present embodiment, the microphone  116  is disposed on the flexible flat cable  130  to which the FM transmitter antenna  131  is connected. Therefore, an independent flexible flat cable for the microphone  116  is not used. As a result, with the mobile phone  100  according to the present embodiment, an increase in the number of components is prevented. 
         [0051]    In the mobile phone  100  according to the present embodiment, the microphone  116  is disposed in a vacant space on the flexible flat cable  130 . Therefore, additional space for housing the microphone  116  is not provided. As a result, with the mobile phone  100  according to the present embodiment, an increase in the space for mounting components, including the microphone  116 , is prevented. 
         [0052]    Referring to  FIG. 7 , a microphone disposed in the fixed housing  120  will be described.  FIG. 7  is an enlarged view of a region surrounding the microphone disposed on the back surface side in the fixed housing  120 . As illustrated in  FIG. 7 , a rear circuit board  125  is disposed in the fixed housing  120 . Various electronic components are mounted on the rear circuit board  125 . 
         [0053]    In the fixed housing  120  of the present embodiment, a microphone  126  is disposed on the rear circuit board  125  at a position close to the opening  124  that is formed in the back case  122 . For example, the microphone  126  is located at a position on the rear circuit board  125  corresponding to the opening  124 . In this case, the ambient noise around the mobile phone  100  enters the fixed housing  120  through the opening  124  and is picked up by the microphone  126 . 
         [0054]    The mobile phone  100  according to the present embodiment removes the ambient noise that is picked up by the microphone  126  from the voice that is picked up by the microphone  116 , and thereby reduces the ambient noise that interferes with a telephone conversation. 
         [0055]    Referring to  FIG. 8 , the relationship between the position of the microphone  116  and the position of the microphone  126  in the mobile phone  100  according to the present embodiment will be described.  FIG. 8  is a schematic sectional view of  FIG. 1  taken along line II-II.  FIG. 8  illustrates the open state in which the movable housing  110  has been slid and the movable housing  110  and the fixed housing  120  overlap in the minimum overlapping area. 
         [0056]    As illustrated in  FIG. 8 , the movable housing  110  has a display surface  110   a , which is positioned on the liquid crystal display  114  side, and a back surface  110   b , which is opposite to the display surface  110   a . In the movable housing  110 , the opening  115  extends through the display surface  110   a . The microphone  116  is disposed close to the opening  115  in the movable housing  110 . 
         [0057]    As illustrated in  FIG. 8 , the fixed housing  120  has a slide surface  120   a , which slides over the back surface  110   b  of the movable housing  110 , and a back surface  120   b , which is opposite to the slide surface  120   a . The slide surface  120   a  is on the keypad  123  side. 
         [0058]    When the movable housing  110  is slid over the fixed housing  120  and the fixed housing  120  and the movable housing  110  overlap in the minimum area H 10 , the fixed housing  120  overlaps a part of the movable housing  110  in which the microphone  116  is disposed. In the fixed housing  120 , the opening  124  extends through a part of the back surface  120   b  corresponding to the minimum area H 10 . The microphone  126  is disposed close to the opening  124  in the fixed housing  120 . 
         [0059]    In the mobile phone  100  according to the present embodiment, when the fixed housing  120  and the movable housing  110  overlap in the minimum area H 10 , the openings  115  and  124  are positioned in the minimum area H 10 . In other words, in the mobile phone  100  according to the present embodiment, the microphones  116  and  126  are positioned in the minimum area H 10 . 
         [0060]    In a mobile phone that includes two microphones, such as the mobile phone  100 , it is preferable that the two microphones be positioned close to each other. This is because the ambient noise that interferes with a telephone conversation is reduced by removing the ambient noise picked up by one of the microphones from the voice picked up by the other microphone. By positioning the two microphones close to each other, the other microphone picks up the ambient noise around the microphone that picks up the voice. As a result, the mobile phone reduces the ambient noise that interferes with a telephone conversation. When a user uses a slide-type mobile phone, such as the mobile phone  100 , as a telephone, the mobile phone is used in the open state. As illustrated in  FIG. 8 , when the mobile phone  100  according to the present embodiment is in the open state, the microphone  116  and the microphone  126  are positioned close to each other. Therefore, the mobile phone  100  according to the present embodiment reduces the ambient noise that interferes with a telephone conversation. 
         [0061]    In the mobile phone  100  according to the present embodiment, the opening  115  is located below the liquid crystal display  114  on the movable housing  110 . The microphone  116  for picking up the voice of a user is disposed close to the opening  115  in the movable housing  110 . In the mobile phone  100  according to the present embodiment, the opening  124  is located close to the center of the fixed housing  120 . The microphone  126  for picking up the ambient noise is disposed close to the opening  124  in the fixed housing  120 . As illustrated in  FIG. 8 , when the mobile phone  100  according to the present embodiment is in the open state, the microphone  116  and the microphone  126  are positioned close to each other. 
         [0062]    When the mobile phone  100  according to the present embodiment is used as a telephone, a user is unlikely to cover the openings  115  and  124 . Therefore, the mobile phone  100  according to the present embodiment picks up the voice of the user and the ambient noise with high precision. With the mobile phone  100  according to the present embodiment, impairment of the sound pickup performance is prevented, so that the ambient noise that interferes with a telephone conversation is reduced and the voice of a user is transmitted to the party on the other end with high quality. 
         [0063]    In the mobile phone  100  according to the present embodiment, the opening  115  is formed in the front case  111  of the movable housing  110  at a position close to the center of the width D 1  of the movable housing  110  in the lateral direction. That is, the microphone  116  is disposed in the movable housing  110  at a position close to the center of the width D 1  of the movable housing  110  in the lateral direction. The opening  124  is formed in the back case  122  of the fixed housing  120  at a position close to the center of the width D 1  of the fixed housing  120  in the lateral direction. The microphone  126  is disposed in the fixed housing  120  at a position close to the center of the width D 1  of the fixed housing  120  in the lateral direction. When the mobile phone  100  according to the present embodiment is used as a telephone, the opening  115  and the opening  124  are prevented from being covered by a user. As a result, with the mobile phone  100  according to the present embodiment, the ambient noise that interferes with a telephone conversation is reduced, and the voice of a user is transmitted to the party on the other end with high quality. The mobile phone  100  according to the present embodiment has an integrated design because the opening  115  and the opening  124  are formed at positions close to the center of the width D 1  of the housing in the lateral direction. 
         [0064]    In the mobile phone  100  according to the present embodiment, the microphone  116  is disposed in a vacant space on the flexible flat cable  130  that is connected to the FM transmitter antenna  131 . Thus, with the mobile phone  100  according to the present embodiment, increase in the number of components such as a flexible flat cable is prevented and an increase in the space for mounting components is prevented. 
         [0065]    In the mobile phone  100  according to the present embodiment, the opening  115  is formed in the movable housing  110  on the liquid crystal display  114  side. Therefore, even in the closed state, the opening  115  is not covered by the housing, whereby the voice of a user is picked up with high precision. 
         [0066]    In the embodiment described above, as in the example illustrated in  FIG. 1 , the opening  115  is formed in the movable housing  110  at a position close to the center of the width D 1  of the movable housing  110  in the lateral direction, and the opening  124  is formed in the fixed housing  120  at a position close to the center of the width D 1  in the lateral direction. The opening  115  need not be formed in the movable housing  110  at a position close to the center of the width D 1  of the movable housing  110  in the lateral direction. The opening  124  need not be formed in the fixed housing  120  at a position close to the center of the width D 1  of the fixed housing  120  in the lateral direction. The microphone  116  is disposed close to the opening  115 , and the microphone  126  is disposed close to the opening  124 . It is preferable that the openings  115  and  124  be disposed at substantially the same position in a direction perpendicular to the movable housing  110  and the slide surface of the fixed housing  120 . In this case, the microphone  116  and the microphone  126  are positioned close to each other even if the openings  115  and  124  are not formed in the movable housing  110  and the fixed housing  120  at positions close to the center of the width D 1  of the movable housing  110  and the fixed housing  120  in the lateral direction. 
         [0067]    In the embodiment described above, the microphone  116  is disposed on the flexible flat cable  130  that is integrated with the FM transmitter antenna  131 . The flexible flat cable on which the microphone  116  is disposed need not be integrated with the FM transmitter antenna, and may be integrated with another type of microphone. 
         [0068]    All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the principles of the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although the embodiments of the present inventions has been described in detail, it should be understood that various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.