Abstract:
The present invention provides a built-in telescopic earphone structure and a terminal device. The built-in telescopic earphone structure comprises a housing having a containing space, an earphone arranged within the containing space and having an earphone assembly and an earphone line, a connection means for connecting the earphone with a terminal device and transmitting signals, and an earphone line retracting means arranged within the containing space for retracting or releasing the earphone line. The built-in telescopic structure can be used to thoroughly solve the problem of earphone resource waste at the terminal device. When a user uses a terminal device (e.g., when using a telephone), it is unnecessary to lift the terminal device up to head, and the user can directly draw the built-in telescopic earphone out of the built-in telescopic earphone structure of the terminal device, thereby the harm caused by electromagnetic radiation from the terminal device is reduced dramatically.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to an earphone line retracting structure, in particular to a built-in telescopic earphone structure and a terminal device. 
       BACKGROUND OF THE INVENTION 
       [0002]    With the extensive application of electronic products such as mobile phones, laptop computers, and the products with capability of aiding hearing, etc., it has been found that the earphone of the above products has problems of winding, knotting, and inconvenience of carrying and keeping in use, which has caused some troubles to users and even further made some users give up using earphone. 
         [0003]    In addition, when using the electronic products directly, the users cannot avoid electromagnetic radiation resulting from the electronic products, causing harm to the users&#39; health. For example, when the user puts the mobile phone on his ear to communicate with other person via a speaker, the electromagnetic radiation resulting from the mobile phone causes harm to the user&#39;s central nerve in brain. It has been found from experiments and study that the harm resulting from electromagnetic radiation to the brain is reduced dramatically when the mobile phone keeps a distance away from the brain by, for example, replacing the speaker inside the mobile phone with a earphone when receiving the sound information. By this way, the harm resulting from electromagnetic radiation to the brain is reduced by more than 90%. 
       SUMMARY OF THE INVENTION 
       [0004]    In order to solve the above problems, an object of the present invention is to provide a built-in telescopic earphone structure and a terminal device so as to reduce the harm resulting from electromagnetic radiation of the terminal device dramatically. 
         [0005]    To achieve the above object, the present invention provides a built-in telescopic earphone structure comprising a housing including a containing space; an earphone arranged within the containing space and including an earphone assembly and an earphone line or earphone lines; a connection means for connecting the earphone with the terminal device and transmitting signals between them; and an earphone line retracting means arranged within the containing space for retracting or releasing the earphone line. 
         [0006]    Preferably, the housing includes a base plate made of hard materials, and a side wall and an upper edge made of soft material. The base plate, the side wall and the upper edge are formed integrally. 
         [0007]    Preferably, the earphone assembly includes a parent-earphone assembly, a child-earphone assembly, and an earphone rod. The parent-earphone assembly and the child-earphone assembly are both arranged on the earphone rod. Also, a switch is provided on the earphone rod for retracting the earphone line. 
         [0008]    Preferably, the built-in telescopic earphone structure further comprises a winding device for winding the earphone line. The winding device includes a plurality of rollers and a belt loop arranged on the plurality of rollers. 
         [0009]    Preferably, the built-in telescopic earphone structure further comprises a battery for supplying electric power to the earphone line retracting means. The battery is arranged within the containing space, and the plurality of rollers is arranged at a side of the battery. 
         [0010]    Preferably, the built-in telescopic earphone structure further comprises a chip processor as the connection means. The chip processor is connected to the battery via a lead wire for controlling charging/discharging of the battery. 
         [0011]    Preferably, the housing is provided with a socket for charging, and the chip processor is connected to the socket for charging via a lead wire. 
         [0012]    The built-in telescopic earphone structure further comprises a conversion plug assembly, one end of which is connected to the chip processor and the other end of which is connected to a terminal device. The chip processor is used to enable the battery and a battery of the terminal device to share the power supply and/or the socket for charging. 
         [0013]    Preferably, the conversion plug assembly includes a lead wire and two plugs at both ends. The plug at one end is connected to the chip processor, and the plug at the other end is inserted to the terminal device. The chip processor is used to communicate the built-in telescopic earphone structure with the terminal device. 
         [0014]    Preferably, the built-in telescopic earphone structure is provided with a plurality of the conversion plug assemblies of different types. 
         [0015]    Preferably, the earphone line retracting means includes a drive means, a winding reel for winding the earphone line, a speed shift means, a clutch, a signal communication means connected to the earphone line, and a signal line extracted therefrom, which are enclosed by the housing to form an assembly. 
         [0016]    Preferably, the drive means of the earphone line retracting means rotates the speed shift means, and the clutch is engaged or disengaged with the winding reel to rotate the winding reel to retract or release the earphone line. 
         [0017]    Preferably, the battery is connected to the drive means in the earphone line retracting means via a lead wire. 
         [0018]    Preferably, the earphone line retracting means further comprises a line-pressing plate for winding the earphone line regularly. 
         [0019]    Preferably, the earphone line comprises bulletproof wires, insulated conductive wires, an earphone line skin, and a plurality of conductors. The conductors consist of a plurality of insulated conductive wires. The insulated conductive wires are arranged in parallel and wound to the bulletproof wires in a spiral fashion. The earphone line skin is attached to and encloses the surface of the insulated conductive wires to form an ultra-thin, flexible and wear-resistant skin. The conductors are located at both ends of the earphone line and connected to the signal communication means of the earphone line retracting means and an O/I port of the earphone respectively when in use. 
         [0020]    Preferably, the earphone comprises an earphone rod having a mounting surface, a first connection part, and a first earphone assembly which is connected to the earphone rod via the first connection part in such a manner that its height is variable relative to the mounting surface. 
         [0021]    Preferably, the first connection part is an elastic sheet, one end of which is fixedly connected to the mounting surface, and the other end of which is fixedly connected to the bottom of the first earphone assembly. 
         [0022]    Preferably, the built-in telescopic earphone structure further comprises a second earphone assembly having a second connection part. The earphone rod has a receiving part, and the second earphone assembly is detachably connected to the earphone rod via the second connection part and the receiving part. 
         [0023]    Preferably, the built-in telescopic earphone structure further comprises a joint which convert double earphone lines which are connected to the first earphone assembly and the second earphone assembly to a single earphone line. A transmitter is provided at the joint. 
         [0024]    Preferably, the built-in telescopic earphone structure further comprises an winding line groove surrounding the earphone rod for winding a second earphone line connected to the second earphone assembly. 
         [0025]    To achieve the above object, the present invention further provides a terminal device comprising a main body and the built-in telescopic earphone structure as mentioned above. The connection means in the built-in telescopic earphone structure is used to effect the connection of the earphone with the main body and the transmission of signals. 
         [0026]    Preferably, the terminal device is a mobile phone, a panel computer, a laptop computer, a desktop computer, a television, a hand-held computer, a telephone, a personal audio-visual device, a digital player, a navigation device or a game machine. 
         [0027]    To achieve the above object, the present invention further provides a built-in telescopic earphone structure capable of solving the problems of winding and knotting when retracting the earphone line, and providing dual-channel output effection. The built-in telescopic earphone structure comprises a parent-earphone assembly and a child-earphone assembly. 
         [0028]    The parent-earphone assembly comprises a parent-earphone receiver, and a first earphone line retracting means for retracting the child-earphone line. The child-earphone assembly includes a child-earphone receiver. The parent-earphone receiver is connected to the parent-earphone line. One end of the child-earphone line is connected to the parent-earphone line via a first signal connection unit, and the other end is connected to the child-earphone receiver. 
         [0029]    Preferably, the parent-earphone assembly further comprises a parent-earphone front cover and a parent-earphone rear cover. The parent-earphone receiver is arranged between the parent-earphone front cover and the parent-earphone rear cover, and the first earphone line retracting means is arranged between the parent-earphone receiver and the parent-earphone rear cover. 
         [0030]    The child-earphone assembly further comprises a child-earphone front cover and a child-earphone rear cover, and the child-earphone receiver is arranged between the child-earphone front cover and the child-earphone rear cover. 
         [0031]    Preferably, the parent-earphone assembly further comprises a parent-earphone rod arranged on the parent-earphone rear cover. The child-earphone assembly may be clamped to the parent-earphone rod via a buckle. 
         [0032]    Preferably, the built-in telescopic earphone structure further comprises a transmitter which is arranged on the parent-earphone rod and connected to the parent-earphone line. 
         [0033]    Preferably, the first earphone line retracting means comprises a winding reel which is arranged on a main shaft. The winding reel is provided with an annular flange. Inside the annular flange is provided with a torsion spring, an outer end of which is fixedly arranged on the annular flange and an inner end of which is fixedly arranged on the main shaft for rotating the winding reel to retract the child-earphone line. The child-earphone line wound on the winding reel is connected to the parent-earphone line via the first signal connection unit. 
         [0034]    Preferably, the first earphone line retracting means is further provided with a braking means for controlling rotation of the winding reel. 
         [0035]    Preferably, the built-in telescopic earphone structure further comprises a second earphone line retracting means having an electric motor for providing driving force. The electric motor drives the winding reel arranged on the main shaft via a speed shift means, and the parent-earphone line wound on the winding reel is connected to external signals via a second signal connection unit. 
         [0036]    Preferably, the speed shift means comprises a screw connected to a drive shaft of the electric motor; a first gear which is a two-stage gear and one stage of which is vertically meshed with the screw; and a second gear which is arranged on the same main shaft as the winding reel, and meshed with the other stage of the first gear. The second gear drives the winding reel to retract the parent-earphone line. 
         [0037]    Preferably, the second earphone line retracting means further comprises a housing having an upper housing part and a base. A side wall of the housing is provided with an opening in which a pulley wheel is arranged. The pulley wheel is arranged on the base via a pulley wheel shaft, and the parent-earphone line extends out of the housing via the pulley wheel. 
         [0038]    Preferably, the second earphone line retracting means further comprises a clutch means arranged between the electric motor and the winding reel so as to effect engagement or disengagement of the electric motor with the winding reel. 
         [0039]    Preferably, the clutch means includes a compression spring arranged on the main shaft. One end of the compression spring is in contact with a bottom surface of the base, and the other end is in contact with the second gear. 
         [0040]    Preferably, the second signal connection unit includes a circuit board. The circuit board is provided with a plurality of annular conductive sheets which are connected to the parent-earphone line. The conductive sheets are connected to external signals via a spring feeler and a feeler lead. The spring feeler is in communication with the conductive sheets. 
         [0041]    Preferably, the built-in telescopic earphone structure further comprises a second earphone line retracting means having a drive system; a drive wheel arranged at one side of the drive system and driven thereby; a support wheel arranged at the other side of the drive system; and a winding loop surrounding the drive wheel and the support wheel for winding the parent-earphone line. The parent-earphone line wound on the winding loop is connected to external signals via the second signal connection unit. The drive wheel rotates the support wheel via the winding loop, so that the parent-earphone line is wound on the winding loop and thereby retracted. 
         [0042]    Preferably, the second earphone line retracting means further comprises a clutch means arranged between the drive system and the drive wheel. The drive system drives the drive wheel via the clutch means, and the drive system is separated from the drive wheel when the drive wheel is rotated by releasing the parent-earphone line or the retraction of the earphone line is completed. 
         [0043]    Preferably, the drive system is a micromotor, and the clutch means is a frustum gear. 
         [0044]    Preferably, the drive wheel comprises a first circular side sheet and a second circular side sheet which are connected to each other via a main shaft. An inner side of the first circular side sheet is provided with a plurality of gears circumferentially arranged around the main shaft. 
         [0045]    The micromotor is engaged or disengaged with the frustum gear via the gears arranged on the main shaft of the micromotor. 
         [0046]    Preferably, the winding loop is provided with an winding line groove formed by a plurality of U-shaped line grooves, and the parent-earphone line is wound within the winding line groove when retracted. 
         [0047]    Preferably, the built-in telescopic earphone structure further comprises a long ellipse housing. A side wall of the housing is provided with an opening, through which the parent-earphone line extends out of the housing. 
         [0048]    Preferably, the second signal connection unit comprises, at the outside of the U-shaped line grooves, a plurality of signal communication elastic sheets to which the parent-earphone line is connected, and a plurality of signal communication tracks which are arranged on an inner wall of the housing and capable of being contacted to the signal communication elastic sheets so as to achieve communication. The signal communication tracks consist of annular conductive metal sheets and are connected to signals from a main board of an external terminal via a signal line. 
         [0049]    Preferably, the support wheel is a plurality of balls or rollers arranged in a semicircular manner. 
         [0050]    As can be seen from the above technical solutions, the embodiments of the present invention have the following beneficial effects. 
         [0051]    (1) In one embodiment, the built-in telescopic earphone structure can be used to thoroughly solve the problem of earphone resource waste at the terminal device. When a user uses a terminal device (e.g., when using a telephone), it is unnecessary to lift the terminal device up to head, and the user can directly draw the built-in telescopic earphone out of the built-in telescopic earphone structure of the terminal device, thereby the harm caused by electromagnetic radiation from the terminal device is reduced dramatically. 
         [0052]    (2) In one embodiment, the side wall and the upper edge of the housing are both made of soft materials capable of being stretched and retracted, thus the housing of the built-in telescopic earphone structure can be adapted to mount to the terminal device of any types. 
         [0053]    (3) Different from the traditional earphone line which is thick and stiff, and easy to be broken when it is wound for hundreds of times, the earphone line in this embodiment is very thin and soft, and it will not be broken even if it is wound for tens of thousands of times, thus the requirement of service life of “built-in telescopic earphone” will be met. 
         [0054]    (4) In another embodiment of this invention, the child-earphone line of the child-earphone is retracted by the retracting means on the parent-earphone, thus it will facilitate the retraction of the parent-earphone line (a single line), and the child-earphone can be separated from the parent-earphone so as to achieve a dual-channel output. When dual-channel or stereo output is undesired, only the parent-earphone will be used. When dual-channel or stereo output is desired, the child-earphone and the child-earphone line will be drawn out of the parent-earphone, and the child-earphone and the parent-earphone are put on the two ears respectively so as to receive audio message. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0055]      FIG. 1  is a front view showing a built-in telescopic earphone structure according to the first embodiment of the present invention; 
           [0056]      FIG. 2  is a side view showing a built-in telescopic earphone structure according to the first embodiment of the present invention; 
           [0057]      FIG. 3  is a front view showing a housing of the built-in telescopic earphone structure according to the first embodiment of the present invention; 
           [0058]      FIG. 4  is a sectional view showing a housing of the built-in telescopic earphone structure according to the first embodiment of the present invention; 
           [0059]      FIG. 5  is a structural schematic view showing a battery and a winding device of the built-in telescopic earphone structure according to the first embodiment of the present invention; 
           [0060]      FIG. 6  is a structural schematic view after the earphone line of the built-in telescopic earphone structure is drawn out of the housing according to the first embodiment of the present invention; 
           [0061]      FIG. 7  is a structural schematic view showing an earphone according to the first embodiment of the present invention; 
           [0062]      FIG. 8  is a structural schematic view showing an earphone assembly including a parent-earphone assembly and a child-earphone assembly according to the first embodiment of the present invention; 
           [0063]      FIG. 9  is a structural schematic view after the earphone assembly including a parent-earphone assembly and a child-earphone assembly attached to an earphone rod according to the first embodiment of the present invention; 
           [0064]      FIG. 10  is a structural schematic view showing another earphone structure of the earphone assembly including a parent-earphone assembly and a child-earphone assembly according to the first embodiment of the present invention; 
           [0065]      FIG. 11  is a schematic view showing an earphone line retracting means according to the first embodiment of the present invention; 
           [0066]      FIG. 12  is a perspective sectional view showing the structure of an earphone line according to the first embodiment of the present invention; 
           [0067]      FIG. 13  is a perspective sectional view slowing the structure of end portions of the earphone line according to the first embodiment of the present invention; 
           [0068]      FIG. 14  is a schematic view when the earphone line retracting means is applied to a terminal device according to the first embodiment of the present invention; 
           [0069]      FIG. 15  is a schematic view showing a built-in telescopic earphone structure according to the second embodiment of the present invention; 
           [0070]      FIG. 16  is a sectional schematic view showing a built-in telescopic earphone structure according to the second embodiment of the present invention; 
           [0071]      FIG. 17  is a side view showing a built-in telescopic earphone structure according to the second embodiment of the present invention; 
           [0072]      FIG. 18  is a sectional view showing a first earphone line retracting means in the built-in telescopic earphone structure according to the second embodiment of the present invention; 
           [0073]      FIG. 19  is a schematic view showing a first earphone line retracting means in the built-in telescopic earphone structure according to the second embodiment of the present invention; 
           [0074]      FIG. 20  is a schematic sectional view showing the structure of the second earphone line retracting means according to the second embodiment of the present invention; 
           [0075]      FIG. 21  is a schematic view showing the relationship among a drive system, a clutch means and a drive wheel in the second earphone line retracting means according to the second embodiment of the present invention; 
           [0076]      FIG. 22  is a schematic view showing the cross sections of a winding loop and U-shaped line grooves provided on the winding loop in the second earphone retracting means according to the second embodiment of the present invention; 
           [0077]      FIG. 23  is a schematic view showing the relationship among the U-shaped line grooves, a signal connection means and a housing in the second earphone line retracting means according to the second embodiment of the present invention; 
           [0078]      FIG. 24  is a sectional view showing the second earphone line retracting means according to the second embodiment of the present invention; 
           [0079]      FIG. 25  is an exploded view showing the structure of the second earphone line retracting means according to the second embodiment of the present invention; 
           [0080]      FIG. 26  is a view showing the structure of a second signal connection unit in the second earphone line retracting means as shown in  FIG. 25 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0081]    In order to explain the purpose, the technical solution and the advantages of the present invention in a clearer manner, the present invention is further described hereinafter by combining the embodiments and the Drawings. The illustrative embodiments and the explanation thereof are used herein to explain the present invention, but cannot be regarded as limitation to the present invention. 
       First Embodiment 
       [0082]    As shown in  FIGS. 1-2 , a built-in telescopic earphone structure according to the first embodiment of the present invention comprises: a housing  31  having an containing space (not shown); an earphone  32  arranged within the containing space and having an earphone assembly  321  and an earphone line  322 ; a connection means  33  for connecting the earphone  32  with a terminal device and for transmission of signals; and an earphone line retracting means  34  arranged within the containing space for retracting or releasing the earphone line  322 . 
         [0083]    In this embodiment, functional modules of the terminal device may also be arranged within the containing space, such as a display screen, a processing chip, a receiver, and a camera. Understandably, the shape of the containing space is not defined in this embodiment. 
         [0084]    The terminal device may be a mobile phone, a panel computer, a laptop computer, a desktop computer, a television, a hand-held computer, a telephone, a personal audio-visual device, a digital player, a navigation device or a game machine. 
         [0085]    Referring to  FIGS. 3-4 , in this embodiment, the housing  31  comprises a base plate  311  made of hard materials, side walls  312  and an upper edge  313  made of soft materials. The base plate  311 , the side walls  312  and the upper edge  313  are formed integrally to house the functional modules such as the built-in telescopic earphone structure. 
         [0086]    In this embodiment, the soft materials may be plastic, elastic materials. 
         [0087]    In this embodiment, the base plate  311  is made of hard materials, and the side walls  312  and the upper edge  313  are made of soft materials capable of being stretched and retracted. Understandably, the components of the above-mentioned hard and soft materials are not defined in this embodiment. 
         [0088]    When manufacturing the housing  31 , the side walls  312  and the upper edge  313  are mounted at the sides of the base plate  311 . The side walls  312  and the upper edge  313  made of soft materials are supported by the base plate  311  made of hard materials so as to form a long, basin-shaped article with an inward edge (as shown in  FIGS. 3-4 ). 
         [0089]    Moreover, because the side walls  312  and the upper edge  313  may both be made of soft materials capable of being stretched and retracted, the housing  31  may be adapted to the terminal device of any size. 
         [0090]    In this embodiment and the drawings, merely the earphone assembly  321  which is a double earphone assembly is taken as an example. Of course, the earphone assembly  321  may also be a single earphone assembly, and its built-in telescopic earphone structure has the same structure as that mentioned in this embodiment, thus it is omitted herein. 
         [0091]    Referring to  FIG. 1  again, the earphone assembly  321  comprises a parent-earphone assembly  3211 , a child-earphone assembly  3212  and an earphone rod  3213 . The parent-earphone assembly  3211  and the child-earphone assembly  3212  may be arranged on the earphone rod  3213 . 
         [0092]    When dual-channel or stereo output is undesired, merely the parent-earphone assembly  3211  is used, and when dual-channel or stereo output is desired, the parent-earphone assembly  3211  and the child-earphone assembly  3212  are put on the two ears of a user respectively so as to receive audio messages, and thereby provide the user with dual-channel or stereo output effect. 
         [0093]    In addition, in order to facilitate the operation, the earphone  32  is also provided with a retraction switch  3214  which controls the ON and OFF states of the power supply of a drive means (e.g., a micromotor) in the earphone line retracting means  34  via a signal line provided in the earphone line  322 , thereby to flexibly control the retracting operation of the earphone line  322 . 
         [0094]    Referring to  FIG. 5 , the built-in telescopic earphone structure further comprises a winding device  35  for winding the earphone line  322 . The winding device  35  comprises a plurality of rollers  351  and a belt loop  352  arranged on the plurality of rollers  351 . Understandably, the arrangement mode and the number of the rollers  351  are not defined in this embodiment. 
         [0095]    In this embodiment, baffles are provided at both sides of the rollers  351  so as to form an winding line groove. The belt loop  352  is sleeved on the rollers  351 , and the earphone line  322  is wound on the belt loop  352 . The arrangement of the rollers  351  and the belt loop  352  can effectively reduce the frictional force between the earphone line  322  and the winding device  35  when winding the earphone line  322 . 
         [0096]    Referring to  FIG. 5  again, the built-in telescopic earphone structure further comprises a battery  36  for supplying power to the earphone line retracting means  34 . The battery  36  is arranged within the containing space. 
         [0097]    As shown in  FIG. 5 , the plurality of rollers  351  may, but not limited to, be arranged at a side of the battery  36 . 
         [0098]    In this embodiment, the battery  36  is preferably a rechargeable battery, e.g., a nickel metal hydride battery (Ni-MH battery) or a lithium battery. Of course, the model and type of the battery are not defined in this embodiment. 
         [0099]    Referring to  FIG. 5  again, the earphone line retracting means  34  is arranged at one end of the base plate  311 . The battery  36  and the winding device  35  around the battery  36  are provided in the middle of the base plate  311 . The earphone  32  may be arranged at the other end of the base plate  311  (as shown in  FIG. 5 ). 
         [0100]    When the earphone  32  is to be used, it may be drawn out of the containing space. After use, the earphone  32  is retracted into the containing space through the earphone line retracting means  34 . 
         [0101]    Take the earphone assembly  321  which is a double earphone assembly as an example. A single earphone line is extracted from the earphone line retracting means  34 , and then converted to double earphone lines via a conversion joint  353 . The double earphone lines are wound around the winding device  35  for one circle and then connected to the earphone rod  3213 . Meanwhile, the base plate  311  where the earphone rod  3213  is located is provided with a groove. When the earphone assembly is adapted to a terminal device, the earphone  32  may be pushed out through the groove of the base plate  311 , thereby the earphone assembly  321  and the earphone line  322  may be drawn out so as to use the telephone or listen to music (as shown in  FIG. 6 ). 
         [0102]    In this embodiment, a transmitter  354  may further be provided at the conversion joint  353  which converts a single earphone line to double earphone lines. 
         [0103]    In other words, when the earphone assembly  321  is a double earphone assembly, the earphone line  322  connected to the earphone rod  3213  is double earphone lines, which may be converted to a single earphone line through the convention joint  353 . When the earphone  32  is placed within the containing space, merely a certain length of the double earphone lines, or a certain length of the double earphone lines and the single earphone line, is wound on the winding device  35 , but merely the single earphone line is wound within the earphone line retracting means  34 . Thus, by winding a certain length of the double earphone lines on the winding device  35 , it is able to ensure that the parent-earphone assembly  3211  and the child-earphone assembly  3212  can be wore on the two ears of the user normally. 
         [0104]    In this embodiment, the built-in telescopic earphone structure further comprises a chip processor as the connection means  33 . The chip processor is connected to the battery  36  via a lead wire for controlling charging and/or discharging of the battery  36 . 
         [0105]    In this embodiment, the chip processor may consist of the existing electronic elements for identifying and processing telephoning or listening to music with the earphone, or enabling the battery of the terminal device and the battery of the built-in telescopic earphone structure to share a power supply. Understandably, the type of the chip processor is not defined in this embodiment. 
         [0106]    Referring to  FIGS. 1-2  again, the housing  31  is provided with a socket  37  for charging, to which the chip processor is connected via a lead wire. 
         [0107]    The built-in telescopic earphone structure further comprises a conversion plug assembly  38 , one end of which is connected to the chip processor, and the other end of which is connected to the terminal device. The chip processor is used to enable the battery  36  and the battery of the terminal device to share the power supply and the socket  37  for charging. 
         [0108]    At this time, the battery  36  corresponds to a standby battery of the terminal device, thereby the endurance of the terminal device can be improved effectively. 
         [0109]    In this embodiment, the socket  37  for charging may be realized by a Mini-USB interface. Of course, the structure of the socket  37  for charging is not defined in this embodiment. 
         [0110]    Referring to  FIGS. 1-2  again, the conversion plug assembly  38  comprises a lead wire  381  and two plugs  382 ,  383  at both ends thereof. The plug  382  at one end is inserted into the chip processor, and the plug  383  at the other end is inserted into the terminal device. The built-in telescopic earphone structure is in communication with the terminal device through the chip processor. 
         [0111]    In this embodiment, the built-in telescopic earphone structure may be provided with several conversion plug assemblies  38  of different types, and the user may make choice according to different terminal devices. 
         [0112]    It can therefore be seen that, in this embodiment, on the surface of the base plate  311  is also provided with the socket  37  for charging and the chip processor. Meanwhile, the chip processor is provided with a socket into which the conversion plug assembly  38  is inserted. In  FIG. 1 ,  381  is a lead wire,  383  is a plug inserted into the terminal device adapted, and  382  is a plug inserted into the chip processor. The length of the lead wire  381  may be longer, and several available conversion plug assemblys  38  of different types shall be provided during the adaptation. 
         [0113]    In this embodiment, the socket  37  for charging is connected to the battery  36  via the lead wire. The battery  36  can be connected to the drive means of the earphone line retracting means  34  and meanwhile to the chip processor, and shares a power supply with the battery  36  of the terminal device via the conversion plug assemblies  38 . 
         [0114]    When in use, the application of the terminal device will be completed merely by inserting the conversion plug assembly  38  into the terminal device (e.g., a mobile phone), and then inserting the terminal device into the housing  31  of the built-in telescopic earphone structure. 
         [0115]    In the earphone structure of this embodiment, the earphone assembly is connected in such a manner that its height is variable relative to a mounting surface. When the earphone is to be used, the earphone assembly protrudes from the mounting surface in a relatively high height, and when the earphone is not to be used, the earphone assembly may be much closer to the mounting surface so as to reduce the thickness of the earphone structure as a whole. 
         [0116]      FIG. 7  is a schematic view showing the earphone according to the first embodiment of the present invention. The earphone comprises an earphone rod  71  having a mounting surface, a first connection part  72 , and a first earphone assembly  73  which is connected to the earphone rod  71  via the first connection part  72  in such a manner that its height is variable relative to the mounting surface. 
         [0117]    In the embodiment of the present invention, the first earphone assembly  73  is connected to the earphone rod  71  via the first connection part  72 . However, the first earphone assembly  73  is variable in height relative to the mounting surface of the connection rod  71 . Thus, when the earphone is not to be used, the first earphone assembly  73  protrudes from the mounting surface in a relatively high height, such that it can extend into the auricle, and when the earphone is not to be used, the height of the first earphone assembly  73  may be decreased so as to reduce the thickness of the earphone structure as a whole. 
         [0118]    In the structure as shown in  FIG. 7 , it can be found that the first connection part  72  may be an elastic sheet, one end of which is fixedly connected to the mounting surface, and the other end of which is fixedly connected to the bottom of the first earphone assembly  73 . 
         [0119]    When it needs to use the earphone, the earphone structure is unrestrained. Under the effect of the elastic force of the elastic sheet, the end of the elastic sheet connected to the first earphone assembly  73  is at a first height such that the first earphone assembly  73  can extend into the auricle. 
         [0120]    When it does not need to use the earphone, a certain pressure is applied to the first earphone assembly  73 . Under the effect of the pressure, the first earphone assembly  73  presses the elastic sheet so that the elastic sheet becomes closer to the mounting surface. The height of the first earphone assembly  73  also decreases relative to the mounting surface, thereby the whole thickness of the earphone is reduced so that the earphone can be easily contained in a thinner housing of the electronic device. 
         [0121]    Of course, in the embodiment of the present invention, there may be one or more elastic sheets, e.g., two as shown in  FIG. 7 , or even more. 
         [0122]    According to the above-mentioned description, the first earphone assembly  73  is connected to the earphone rod  71  via the elastic sheet structure in such a manner that its height is variable relative to the mounting surface. Understandably, some other methods may also be used to connect the first earphone assembly  73  to the earphone rod  71  in a height-variable manner, which are described as follows. 
         [0123]    The bottom of the first earphone assembly  73  is mounted with a threaded bolt, and a threaded hole is formed on the earphone rod  71 . When in use, the threaded bolt at the bottom of the first earphone assembly  73  is screwed out of the threaded hole so as to drive the first earphone assembly  73  to move up relative to the mounting surface and to increase the height of the first earphone assembly  73  relative to the mounting surface. When not in use, the threaded bolt at the bottom of the earphone assembly  73  is screwed into the threaded hole so as to drive the first earphone assembly  73  to move down relative to the mounting surface and to decrease the height of the first earphone assembly  73  relative to the mounting surface, so that the thickness of the earphone as a whole is reduced and the earphone can be easily contained in a thinner housing of the electronic devices. 
         [0124]    Understandably, the threaded bolt may also be arranged in such a manner that it projects beyond the mounting surface, and the threaded hole is provided at the bottom of the first earphone assembly  73 , so as to make the relative height of the two variable. 
         [0125]    If the height of the first earphone assembly  73  relative to the mounting surface is decreased/increased in a rotation manner relative to the mounting surface, the earphone line will likely be wound on the threaded bolt. To solve this problem, the first connection part  72  is effected by a spring which is provided on the mounting surface and projects therefrom, and meanwhile the bottom of the first earphone assembly  73  is fixedly connected to the top of the spring. 
         [0126]    When in use, the earphone structure is unrestrained. Under the effect of the elastic force of the spring, the first earphone assembly  73  is at a first height so that it can extend into the auricle. When not in use, a certain pressure is applied to the earphone assembly. Under the effect of the pressure, the first earphone assembly  73  presses the spring. The height of the first earphone assembly  73  decreases relative to the mounting surface, thereby the whole thickness of the earphone structure is reduced so that the earphone structure can be easily contained in a thinner housing of the electronic devices. 
         [0127]    In the above structures, merely the first earphone assembly  73  is mentioned. Understandably, along with the capability becoming more and more greater, the electronic devices can be used for various tasks such playing music, playing video, and etc, thus more and more electronic devices use dual-channel earphone, i.e., the earphone having two earphone assemblies. In this case, the earphone structure further comprises a second earphone assembly  74 , and understandably, it may also use the same structure. 
         [0128]    However, the earphone structure will have a big size if the two earphone assemblies both use the above-mentioned structure. In this embodiment, a certain structure is provided so that the second earphone assembly  74  can be connected to the earphone rod in a detachable manner so as to reduce the size of the earphone structure as a whole. Meanwhile, the earphone structure can be contained in the housing of the electronic device without increasing the thickness of the housing. 
         [0129]    The above-mentioned earphone structure, as shown in  FIG. 8 , further comprises a second earphone assembly  74  having a second connection part  741 . The earphone rod  71  is provided with a receiving part  711 . The second earphone assembly  74  is detachably connected to the earphone rod  71  via the second connection part  741  and the receiving part  711 . 
         [0130]    In this embodiment, several methods can be used to connect the second earphone assembly  74  with the earphone rod  71  in a detachable manner, which are described hereinafter by combining Method  1  and Method  2 . 
         [0131]    &lt;Method  1 &gt; 
         [0132]    As shown in  FIG. 8 , the second connection part  741  is a sheet-like structure provided at the bottom of the second earphone assembly  74 , and a slot  711  is provided on the earphone rod  71  for receiving the sheet-like structure. When not in use, the second connection part  741  of the sheet-like structure is inserted into the slot  711  so that the second earphone assembly  74  is attached to the earphone rod  71 , as shown in  FIG. 9 . When in use, the second connection part  741  of the sheet-like structure is drawn from the slot  711  so that the second earphone assembly  74  is separated from the earphone rod  71 , as shown in  FIG. 8 . 
         [0133]    Of course, the thickness of the first earphone assembly  73  is substantially the same as that of the second earphone assembly  74 . If the depth of the slot  711  is greater than the height of the sheet-like structure, it is able to ensure that the height of the second earphone assembly  74  relative to the mounting surface will not be greater than that of the first earphone assembly  73  relative to the mounting surface when the second connection part  741  of the sheet-like structure is inserted into the slot  711 . Thus, the second earphone assembly  74  can also be contained in the housing of the electronic device without increasing the thickness of the housing. When used alone, the entire size of the earphone structure will also be reduced. 
         [0134]    &lt;Method  2 &gt; 
         [0135]    As shown in  FIG. 10 , the earphone rod is configured as a hollow structure (not shown), and a throughhole  712  is provided on the mounting surface to communicate with the hollow structure. A hook  742  is provided at the bottom of the second earphone assembly  74 . The hook  742  enters the hollow structure via the throughhole  712  so as to attach the second earphone assembly  74  to the earphone rod  71 . When in use, the hook  742  is drawn out through the throughhole  712  so that the second earphone assembly  74  is separated from the earphone rod  71 . 
         [0136]    Using the above-mentioned structure, the height of the second earphone assembly  74  relative to the mounting surface will not be greater than that of the first earphone assembly  73  relative to the mounting surface, and the second earphone assembly  74  can be contained in the housing of the electronic device without increasing the thickness of the housing. When used alone, the entire size of the earphone structure will also be reduced. 
         [0137]    In this embodiment of the present invention, for the earphone structure including a parent-earphone assembly and a child-earphone assembly, each earphone assembly is connected with an earphone line. If the earphone line is too long, it will be wound together and thus is inconvenient to use. 
         [0138]    Therefore, as shown in  FIG. 8 , a joint  75  is also provided. The double earphone lines connected to the first earphone assembly  73  and the second earphone assembly  74  are converted to a single earphone line via the joint  75 , and then connected to an audio interface of the electronic device via the single earphone line. 
         [0139]    Considering the bidirectional audio communication, a transmitter may also be provided at the joint  75  so as to collect acoustic signals. 
         [0140]    Generally, for the earphone structure including double earphone assemblies, the first earphone assembly  73  is fixedly connected to the earphone rod  71 , thus the earphone line connected to the other earphone assembly shall be sufficiently long to enable the other earphone assembly to be placed into the other auricle. 
         [0141]    In order to ensure that the earphone line of the second earphone assembly  74  is sufficiently long, as shown in  FIG. 10 , an winding line groove  713  is provided on the earphone rod  71  for winding the second earphone line connected to the second earphone assembly  74 . 
         [0142]    When not in use, the earphone line of the second earphone assembly  74  is wound in the winding line groove  713 , and when in use, the earphone line can be drawn from the winding line groove  713  and thus its length will be extended. 
         [0143]    Such a structure is especially useful when a joint is provided to convert the double earphone lines to a single earphone line but the earphone line retracting means cannot receive the joint. Further explanation is given as follows. 
         [0144]    Because the joint for the earphone lines cannot be contained into the earphone line retracting means, the earphone lines ahead of the joint must be sufficiently long to ensure that the two earphone assemblies can be placed into the right and left auricles respectively. However, considering that the space inside the electronic device is limited, if the earphone lines ahead of the joint is too long and there is no other auxiliary structure, a long earphone line will not be retracted into the housing of the electronic device when the joint reaches the earphone line retracting means, and a bad effect will be obtained. If the earphone line is precisely retracted into the housing of the electronic device when the joint reaches the earphone line retracting means, the earphone line ahead of the joint is insufficiently long to ensure that the two earphone assemblies can be placed into the right and left auricles respectively. To solve the above-mentioned problem, a part of the earphone line is wound by the winding line groove in this embodiment. When not in use, the earphone line of the second earphone assembly is wound in the winding line groove. At this time, the distance between the earphone assembly and the plug is reduced remarkably, thus the earphone line can be retracted into the housing of the electronic device when the joint reaches the earphone line retracting means. When in use, the earphone line is drawn from the winding line groove, and the earphone line ahead of the joint is lengthened so that the two earphone assemblies can be placed in the right and left auricles respectively. 
         [0145]    Referring to  FIGS. 11-12 , the earphone line retracting means  34  comprises a drive means  341 , a winding reel  342  for winding the earphone line  322 , a speed shift means  343 , a clutch  344  and a signal communication means  345  connected to the earphone line  322 , which are enclosed within the housing to form an assembly. 
         [0146]    In this embodiment, the drive means  341  of the earphone line retracting means  34  is engaged or disengaged with the winding reel  342  via the speed shift means  343  and the clutch  344 , and rotates the winding reel  342  to retract or release the earphone line  322 . The battery  36  is connected to the drive means  341  of the earphone line retracting means  34  via a lead wire. 
         [0147]    The earphone line retracting means  34  further comprises a line pressing plate  346  for winding the earphone line  322  regularly. 
         [0148]    In this embodiment, the drive means  341  may be a micromotor, a spring or any other drive means capable of supplying power. Preferably, the drive means  41  is a micromotor. 
         [0149]    In this embodiment, the clutch  344  consists of a gear  3432 , a spring and a friction plate, and the engagement or disengagement is effected by the resistance. The speed shift means  343  consists of a plurality of gears (e.g., gears  3431 ,  3432 ,  3433 ) which cooperate with each other to provide proper rotation speed. 
         [0150]    In this embodiment, the speed shift means  343  is provided so as to decelerate the micromotor, thereby to increase the moment. The clutch  344  is provided so as to separate the winding reel  342  from the micromotor when excessive resistance occurs. This will protect the micromotor and operate the micromotor safely, and meanwhile the earphone line  322  can be easily drawn out. 
         [0151]    The line pressing plate  346  is provided so that the earphone line  322  wound in the winding reel  342  is not loosen but arranged regularly. 
         [0152]    In this embodiment, in order to enable the earphone line  322  in the built-in telescopic earphone structure to be retracted and released freely, the earphone line  322  may be soft and slim. 
         [0153]    Referring to  FIGS. 12-13 , the earphone line  322  comprises bulletproof wires  3221 , insulated conductive wires  3222 , and an earphone line skin  3223 . The earphone line  22  further comprises a plurality of conductors  3224  consisting of a plurality of insulated conductive wires  3222 . The insulated conductive wires  3222  are arranged in parallel and wound to the bulletproof wires  3221  in a spiral fashion. The earphone line skin  3223  is attached to and encloses the surface of the insulated conductive wires  3222  to form an ultra-thin, soft and wear-resistant skin. The conductors  3224  are located at both ends of the earphone line  322  and connected to the connection means  33  and an O/I port of the earphone  32  respectively when in use. 
         [0154]    Referring  FIGS. 12-13 , the earphone line  322  of the present invention is configured in such a manner that the plurality of insulated conductive wires  3222  are arranged in parallel, wound to the bulletproof wires  3221  tightly and integrated into the earphone line skin  3223  so as to manufacture the semi-manufactured earphone line  322 . Then, the earphone line is cut according to the desired length, the skins at the two ends of the earphone line are peeled off to expose the insulated conductive wires  3222 , and every couple of the insulated conductive wires  3222  is grouped to form the conductor  3224 . 
         [0155]    Generally, the earphone line  322  consists of 3 to 8 conductors  3224  (as shown in  FIG. 13 ). 
         [0156]    It is to be indicated that, the bulletproof wires  3221  are formed by a plurality of fine threads having strong tensile force, so as to enhance the tensile strength of the manufactured earphone line  22 . The earphone line skin  3223  is made of a high-molecular material with good wear-resistance, strong adhesion and excellent flexibility, so as to enhance the flexibility and wear-resistance of the manufactured earphone line  22 . 
         [0157]    For the earphone line  322  manufactured according to the above technology and process, because the insulated conductive wires  3222  are arranged in parallel and wound on the bulletproof wires  3221  and then integrated into the earphone line skin, there is no gap or “trench” within the earphone line  322 , thereby the bending angle of the earphone line  322  is reduced during the winding, and the curling radius and gap of the earphone line  322  are reduced too. (According to the known technology, a plurality of electric wires are wound on a bulletproof wire  3221  to form a conductor  3224 , a plurality of conductors  3224  are wound together on another bulletproof wire  3221  and then integrated into the earphone line skin to form an earphone line. For the earphone line manufacture by this technology and process, there are relatively big gaps and trenches within the earphone line, thus more materials will be filled thereinto and the earphone line is thick and stiff. Moreover, the curling radius and the gap of the earphone line will be increased during the winding, thus the earphone line is more easily to be broken and damaged.) However, the earphone line manufactured by the above-mentioned new technology and process will not be broken even if it is wound for tens of thousands of times within a small space, thus the design requirement and purpose of the built-in telescopic earphone structure will be achieved. 
         [0158]    In this embodiment, the present invention further provides a terminal device comprising a main body and the built-in telescopic earphone structure as mentioned above. The connection of the earphone with the main body and the transmission of signal can be effected through the connection means in the built-in telescopic earphone structure. 
         [0159]    In this embodiment, the terminal device is a mobile phone, a panel computer, a laptop computer, a desktop computer, a television, a hand-held computer, a telephone, a personal audio-visual device, a digital player, a navigation device or a game machine. 
         [0160]      FIG. 15  is a schematic view when the earphone line retracting means is applied to the terminal device. The terminal device comprises a mobile phone housing, a built-in telescopic earphone structure  150  arranged within the housing; an earphone line  151 , one end of which is connected to the built-in telescopic earphone structure and the other end of which is connected to an audio processing chip of the mobile phone through a signal wire from the signal communication means in the earphone line retracting means; and an earphone line retracting means  152  arranged within the housing for winding the earphone line. 
         [0161]    The earphone line retracting means  152 , the earphone line  151  (a signal earphone line or double earphone lines), a joint  153 , a transmitter  154  and double earphones  150  can be directly arranged within the housing of the terminal device (as shown in  FIG. 14 ). The joint  153  can convert the single earphone line to double earphone lines of the earphone line  151 . If the double earphone lines are not sufficiently long, the single earphone line can be wound on the earphone rod for several circles (as shown in  FIG. 10 ) so as to increase the length of the earphone line. 
       Embodiment 2 
       [0162]      FIGS. 15-18  are schematic views showing a built-in telescopic earphone structure according to the second embodiment of the present invention. 
         [0163]    The built-in telescopic earphone structure comprises a parent-earphone assembly and a child-earphone assembly. The parent-earphone assembly comprises a parent-earphone receiver  52 , and a first earphone line retracting means  53  for winding a child-earphone line  512 . The child-earphone assembly comprises a child-earphone receiver  59 . The parent-earphone receiver  52  is connected to a parent-earphone line  6 . One end of the child-earphone line  512  is connected to the parent-earphone line  6  through a first signal connection unit  5106 , and the other end is connected to the child-earphone receiver  59 . 
         [0164]    The parent-earphone assembly comprises a parent-earphone front cover  51 , a parent-earphone rear cover  54 , the parent-earphone receiver  52  arranged between the parent-earphone front cover  51  and the parent-earphone rear cover  54 , and further includes the first earphone line retracting means  53  arranged between the parent-earphone receiver  52  and the parent-earphone rear cover  54  for winding the child-earphone line. The child-earphone assembly comprises a child-earphone front cover  58 , a child-earphone rear cover  510 , and the child-earphone receiver  59  arranged between the child-earphone front cover  58  and the child-earphone rear cover  510 . 
         [0165]    The parent-earphone receiver  52  is connected to the parent-earphone line  6 . One end of the child-earphone line  512  is connected to the parent earphone line  6  through the first signal connection unit  5106 , and the other end is connected to the child-earphone receiver  59 . 
         [0166]    The parent-earphone assembly further comprises a parent-earphone rod  55  arranged on the parent-earphone rear cover  54 , and the child-earphone assembly is clamped to the parent-earphone rod  55  through a buckle  516 . 
         [0167]    When only one earphone (the parent-earphone) needs to be used, the child-earphone line  512  is retracted in the first earphone line retracting means  53  of the parent-earphone assembly, and the child-earphone assembly is clamped to the parent-earphone rod  55  through the buckle  516 . At this time, the other end is clamped at  516  of the parent-earphone rod, thus the parent-earphone assembly is integrally formed with the child-earphone assembly (as shown in  FIG. 1 ) apparently. When double earphones are required, the child-earphone line  512  may be drawn from the first earphone line retracting means  53  of the parent-earphone assembly, and then the child-earphone is put on the other ear so as to obtain the dual-channel or stereo output. 
         [0168]    The child-earphone rear cover  510  of the child-earphone assembly may also be provided with a child-earphone rod  511 . When the child-earphone assembly is not needed, the child-earphone rod  511  may be inserted into an insert opening  515  of the parent-earphone assembly, so that the parent-earphone assembly is formed integrally with the child-earphone assembly apparently. 
         [0169]    In addition, the built-in telescopic earphone structure further comprises a transmitter  56  arranged on the parent-earphone rod  55  and connected to the parent-earphone line  6 . The parent-earphone assembly may further be provided with a switch  514  for controlling the second earphone line retracting means. 
         [0170]    It is to be indicated that, in order to achieve a better effect, the child-earphone line  512  of the present invention may be thinner and shorter than the parent-earphone line  6 . For example, the child-earphone line  512  of merely 30-40 centimetres is required. Thus, the first earphone line retracting means  53  for retracting the child-earphone line  512  may be designed with a miniature size. The parent-earphone line  6  usually has a length of 1 meter or longer, and a diameter larger than that of the child-earphone line  512 , thus the second earphone line retracting means for retracting the parent-earphone line  6  is bigger than the first earphone line retracting means  53 . However, the first earphone line retracting means  53  and the second earphone line retracting means are substantially constructed in the same way, and there is no obvious difference therebetween. That is, they may be replaced with each other, and both can be driven by a spring or a micromotor. 
         [0171]    In addition, the child-earphone line  512  may comprise 2 signal lines, and the parent-earphone line  6  may comprise 4 or more signal lines. The size and length of the child-earphone line  512  and the parent-earphone line  6 , and the number of the signal lines are not defined in present invention, and the range of the present invention is not limited to the preferred technical solutions. 
         [0172]    Referring to  FIGS. 18 and 19 , the first earphone line retracting means  53  comprises a winding reel  5102  arranged on a main shaft  5103 , an annular flange  5112  arranged on the winding reel  5102 , and a torsion spring  513  arranged within the annular flange  5112 . An outer end of the torsion spring  513  is fixedly connected to the annular flange  5112 , and an inner end thereof is fixedly connected to the main shaft  5103 . The child-earphone line  512  wound on the winding reel  5102  is connected to the parent-earphone line  6  through a first signal connection unit  5106 . 
         [0173]    The first earphone line retracting means  53  is further provided with a braking means  5109  for controlling rotation of the winding reel  5102 , and a housing  5101 . 
         [0174]    Preferably, the main shaft  5103  is a hollow, circular shaft. The parent-earphone line  6  passes through the circular shaft and connects with the parent-earphone receiver  52 , and a signal line is branched therefrom to be connected with the child-earphone line  512  through the first signal connection unit  5106 . 
         [0175]    Referring to  FIG. 19 , in the first earphone line retracting means  53 , the spring and the winding reel  5102  are arranged in an inside-outside manner, and in the other embodiments of the present invention, they may also be arranged in a left-right manner (as shown in  FIG. 18 ) or in any other arrangements, which are not defined in the present invention. 
         [0176]    It is to be indicated that, apart from the above-mentioned structure, the first earphone line retracting means  53  may also use the structure of the second earphone line retracting means described below. In other words, in the present invention the first earphone line retracting means  53  has substantially the same structure as the second earphone line retracting means, and they can be replaced with each other. 
         [0177]    In another embodiment of the present invention, the built-in telescopic earphone structure further comprises the second earphone line retracting means. 
         [0178]      FIG. 20  is a sectional view of the first embodiment showing the second earphone line retracting means according to the second embodiment of the present invention. The second earphone line retracting means comprises a drive system  1 , a drive wheel  2 , a support wheel  20  and a winding loop  3 . 
         [0179]    The drive system  1  may be a micromotor, a spring or any other drive means capable of supplying power. In this embodiment, the drive system  1  is preferably a micromotor. 
         [0180]    The drive wheel  2  is arranged at one side of the drive system  1  and driven by the drive system  1 . The support wheel  20  is arranged at the other side of the drive system  1 . The winding loop  3  surrounds the drive wheel  2  and the support wheel  20  for winding the parent-earphone line  6 . The parent-earphone line  6  wound on the winding loop  3  is connected to an external signal through the second signal connection unit. The drive wheel  2  rotates the support wheel  20  through the winding loop  3  so that the parent-earphone line  6  is wound on the winding loop  3  to retract the earphone line. 
         [0181]    The second earphone line retracting means further comprises a clutch means  8  arranged between the drive system  1  and the drive wheel  2 . The drive system  1  drives the drive wheel  2  through the clutch means  8 , and the drive system  1  is separated from the drive wheel  2  when the drive wheel  2  is rotated by releasing the parent-earphone line  6 . 
         [0182]    In this embodiment, when a retracting operation of the parent-earphone line  6  is performed, the drive system  1  (e.g., a micromotor) operates to drive the drive wheel  2  through the clutch means  8 . The drive wheel  2  rotates the support wheel  20  through the winding loop  3 , so that the parent-earphone line  6 , one end of which is fixed onto the winding loop  3 , can be wound on the winding loop  3 . When a releasing operation of the parent-earphone line  6  is performed (i.e., when the user draws out the parent-earphone line  6 ), the parent-earphone line  6  rotates the drive wheel  2 , the winding loop  3  and the support wheel  20 . At this time, the drive system  1  and the drive wheel  2  are separated from each other through the clutch means  8  so as to reduce the resistance to drawing the earphone line, and the drive system  1  (e.g., a micromotor) will not be affected. Meanwhile, when the retracting operation of the parent-earphone line  6  is completed or the resistance to retracting the earphone line exceeds a preset value, the clutch means  8  can cause the drive wheel  2  and the drive system  1  to skid with each other, or separate the drive system  1  from the drive wheel  2 , so as to race the drive system  1  such as a micromotor, and thereby to protect the micromotor from being damaged. 
         [0183]    Referring to  FIG. 21 , the clutch means  8  is preferably a frustum gear. Understandably, it may also be a conical gear, a cylindrical gear or any other types of clutch means  8 , which are not defined in the present invention. 
         [0184]    The drive wheel  2  comprises a first circular side sheet  22  and a second circular side sheet  21 , which are fixed through a main shaft  23 . As shown in  FIG. 21 , an inner side surface of the first circular side sheet  22  is provided with a plurality of gears  9  arranged around the main shaft  23  in the circumference manner. The micromotor is engaged with the frustum gear (the clutch means  8 ) through a gear  18  arranged on the main shaft of the micromotor, and the frustum gear is engaged with the gears  9  on the drive wheel  2 , so that the drive system  1  drives the drive wheel  2  through the frustum gear. 
         [0185]    If the clutch means  8  is a gear, the gear arranged on the main shaft of the micromotor and the gears  9  arranged on the drive wheel  2  are fitted to the gear as the clutch means  8 . If the clutch means  8  is a frustum gear, the gear arranged on the main shaft of the micromotor is also a frustum gear, and they are meshed with each other. If the clutch means  8  is a conical gear, the gear arranged on the main shaft of the micromotor may also be a conical gear. Thus, when the micromotor is operating, the gear on the main shaft of the micromotor is tightly engaged with the gear as the clutch means  8 , and the gear as the clutch means  8  is then tightly engaged with the gears  9  of the drive wheel  2 , so as to drive the drive wheel  2  rotate. When the drive wheel  2  is rotated by releasing the parent-earphone line  6 , the gear as the clutch means  8  is disengaged and no longer engaged with the gears of the drive wheel  2  and the micromotor, so that the parent-earphone line  6  can be drawn out easily. Moreover, when the drive wheel  2  is rotating, it will not rotate the micromotor, thus there will be no adverse effect on the micromotor. 
         [0186]    The second earphone line retracting means further comprises an ellipse housing  5 . A side wall of the housing  5  is provided with an opening, through which the parent-earphone line  6  extends out of the housing  5 . 
         [0187]    Due to the drive system  1 , the drive wheel  2  and the support wheel  20 , the second earphone line retracting means has an ellipse appearance so as to minimize the size and to wind much longer parent-earphone line  6 . 
         [0188]    Referring to  FIG. 22 , in this embodiment of the present invention, the winding loop  3  may be a belt loop or a pedrail structure made of the materials such as plastics, metals or metalloids. To fix the wound parent-earphone line  6  in a better manner, a plurality of U-shaped line grooves  4  are provided on the winding loop  3  at regular intervals (preferably 2 to 8 mm). The plurality of U-shaped line grooves  4  are arranged together to form a winding line groove, in which the parent-earphone line  6  is wound when retracted. 
         [0189]    Referring to  FIG. 23 , the second signal connection unit comprises a plurality of signal communication elastic sheets  15  arranged outside the U-shaped line grooves  4  and connected to the parent-earphone line  6  through an earphone signal line, and a plurality of signal communication tracks  16  arranged on an inner wall of the housing  5  and capable of being in contact with the signal communication elastic sheets  15 . The signal communication tracks  16  consist of annular conductive metal sheets and are connected to a signal from a main board of the external terminal by the signal line. 
         [0190]    An end of the parent-earphone line  6  is fixed to the U-shaped line groove  4 , and several earphone signal lines are branched therefrom to be connected with the signal communication elastic sheets  15 . 
         [0191]    It is to be indicated that, the signal communication elastic sheets  15  are provided at the U-shaped line groove  4  to which the end of the earphone line is fixed, and the signal communication tracks  16  need to surround the inner side surface of the housing  5  for a whole circle. When the signal communication elastic sheets rotate along with the U-shaped line groove  4 , they are in slip friction contact with the signal communication tracks  16  so as to ensure a communication state at any time. 
         [0192]    In this embodiment, the support wheel  20  is a circular article. In another embodiment, referring to  FIG. 24 , the support wheel  20  is a plurality of balls or rollers  25  or any other rollable or slidable articles arranged in a semicircular manner. As compared with the circular article as the support wheel  20 , the use of balls or rollers can reduce the size of the earphone line retracting means in a better manner. 
         [0193]    In this embodiment, due to the drive system  1 , the drive wheel  2  and the support  20  in the second earphone line retracting means, the length of the parent-earphone line  6  to be wound is increased remarkably, and the size of the earphone line retracting means is reduced. The second earphone line retracting means with reduced size can be fitted to the mobile terminals of different types in a better manner. 
         [0194]    In addition, a speed shift means is automatically formed by the interaction between a main shaft gear of the drive system  1  as well as an inner side gear of the drive wheel  2  and the winding loop  3 . Thus, the torsion of the drive system  1  such as a micromotor and the length of the parent-earphone line  6  to be wound will be increased remarkably. 
         [0195]      FIG. 25  is an exploded view showing the second earphone line retracting means according to the second embodiment of the present invention. The second earphone line retracting means comprises an electric motor  111 , a speed shift means, a winding reel  115 , a second signal connection unit  116  and a housing. When the second earphone line retracting means is arranged within the other terminals or used as the first earphone line retracting means  53 , the housing may be omitted. 
         [0196]    The electric motor  111  is used for supplying driving force to the winding reel  115 . The speed shift means rotates the winding reel  115 , and the electric motor  111  is supplied with electric power from an external power supply and controlled by an external switch. The external power supply and the external switch are not shown in the drawings. 
         [0197]    In another embodiment of the second earphone line retracting means of the present invention, the speed shift means comprises a screw  112  connected to a drive shaft of the electric motor  111 , a first gear  113  and a second gear  114 . The first gear  113  is a two-stage gear, one stage of which is vertically meshed with the screw  112 , and the other stage of which is engaged with the second gear  114 . The second gear  114  drives the winding reel  115  to retract the earphone line. 
         [0198]    The housing comprises an upper housing  118  and a base  117 . The electric motor  11  is arranged parallel to the bottom of the base  117 . The first gear  113  is arranged perpendicular to the bottom of the base  117  through a gear shaft  1117 . The base  117  is provided with a main shaft  1118  perpendicular to the bottom. The second gear  114 , the winding reel  115  and the second signal connection unit  116  are provided on the main shaft  1118 . Such an arrangement can minimize the size of the earphone line retracting means. 
         [0199]    It is to be indicated that, the two gears as shown in  FIG. 25  are merely used to illustrate this embodiment conveniently, and the number of the gears is not defined in the present invention. A person skilled in the art may determine the number and size of the gears, and the location relationship between the electric motor  111  and the winding reel  115  according to the practical need. For example, three or more gears may be provided, and the sizes of the gears are set in proportion so as to form a speed shift means for controlling the rotation speed of the winding reel  115  driven by the motor  111 . 
         [0200]    In another embodiment of the second earphone line retracting means, the electric motor  111  may be arranged parallel to the main shaft  1118 . At this time, the speed shift means may comprise at least one gear. The gear is provided on the main shaft  1118  and engaged with the screw  112 , and the electric motor  111  drives the winding reel  115  rotate. Of course, a person skilled in the art may also determine the number and size of the gears, and the location relationship between the electric motor  111  and the winding reel  115  according to the practical need. For example, two or more gears may be provided, and the sizes of the gears are set in proportion so as to form a speed shift means for controlling the rotation speed of the winding reel  115  driven by the electric motor  111 . The difference between this embodiment and the first embodiment lies in that the electric motor  111  is arranged perpendicularly, thus the size of the earphone line retracting means may be increased. 
         [0201]    The side wall of the housing is provided with an opening  119 , in which a pulley wheel  1111  is provided. The pulley wheel  1111  is arranged on the base  117  through a pulley wheel shaft  1112 , and the parent-earphone line  6  extends out of the housing through the pulley wheel  1111 , so as to reduce the friction between the parent-earphone line  6  and the housing and to protect the parent-earphone line  6  in a better manner. 
         [0202]    The winding reel  115  may also be provided with a baffle  1113  for separating the second gear  114  from the parent-earphone line  6  on the winding reel  115 . Thus, the parent-earphone line  6  may be wound on the winding reel  115  in a better manner so as to protect the parent-earphone line  6 . 
         [0203]    If the electric motor  111  directly rotates the winding reel  115  to retract the earphone line, because the electric motor  111  rotates at as high as thousands of rpm (rounds per minute) to tens of thousands of rpm, the parent-earphone line  6  is retracted instantly by the winding reel  115 , so that the too high speed of the retraction of the earphone line may cause damage to the device and the user. By contrast, in the present invention, there are a plurality of gears which transmit with each other, thus the rotate speed of the winding reel  115  is reduced to a proper and safe range and at the same time torque of the electric motor  111  is increased. 
         [0204]      FIG. 26  is a view showing the second signal connection unit  116  in the second earphone line retracting means. 
         [0205]    The second signal connection unit  116  comprises a circuit board  220  and a plurality of annular conductive sheets  230 . The plurality of annular conductive sheets  230  are connected to one end of the parent-earphone line  6 , and to an external signal line (a signal line inside another terminal when the second earphone line retracting means is provided in the terminal) through a spring feeler  1110  and a lead wire (not shown). By using this structure, when the winding reel  115  is rotated to wind or unwind the parent-earphone line  6 , one end of the parent-earphone line  6  is in communication with an external signal through the annular conductive sheets  230  and the spring feeler  1110  all the time, thus communication and effectiveness of the signal will be maintained. Of course, the second signal connection unit  116  may also be a wireless signal connection unit. 
         [0206]    In another embodiment, the second earphone line retracting means further comprises a clutch means having a compression spring  1115  arranged on the main shaft. One end of the compression spring  1115  is in contact with the bottom of the base through a pushing ring  1116 , and the other end is in contact with the second gear  114  through a gasket  1114 . 
         [0207]    Understandably, the compression spring  1115  is merely one of the clutch means, and the clutch means may be achieved by the other methods. 
         [0208]    The electric motor  111  drives the winding reel  115  to retract the earphone line through the screw  112 , the first gear  113  and the second gear  114 . When the retraction of the earphone line is completed, usually the user will not turn off the power supply of the electric motor  111  in time, thus the electric motor  111  will continue to operate. At this time, the voltage and torsion of the electric motor  111  increases, and the clutch means causes the second gear  114  in contact with the compression spring  1115  to race while the winding reel  115  is not rotating, thus the components such as the electric motor  111  and the parent-earphone line  6  will be protected effectively. 
         [0209]    In addition, the present invention further provides a mobile terminal comprising, apart from the main body, the built-in telescopic earphone structure as described above. The main body may be any electronic device using the earphone, such as MP3, MP4, MP5, a computer, a handheld game machine or a mobile phone. 
         [0210]    According to the present invention, a double earphone structure including a parent-earphone and a child-earphone is provided, and an earphone line retracting means is provided on the parent-earphone to retract the child-earphone line  512 . Such a structure may facilitate not only the retraction of the parent-earphone line (a single line), but also the separation of a child-earphone from the parent-earphone so as to achieve dual-channel output effection. When dual-channel or stereo output is undesired, merely the parent-earphone is used, and when dual-channel or stereo output is desired, the child-earphone and the child-earphone line  512  can be drawn out of the parent-earphone, and the child-earphone and the parent-earphone are put on the two ears respectively so as to receive audio message. 
         [0211]    The above embodiments are merely preferred ones of the present invention, and it shall be indicated that, improvements and modifications may also be made by a person skilled in the art without departing from the principle of the present invention, and these improvements and modifications shall also be considered as within the range of the present invention.