Abstract:
An electronic device includes a speaker element having a diaphragm and a driving unit that vibrates the diaphragm; a mounting unit, in a housing, to which the speaker element is mounted; and an enclosure formed next to the mounting unit. The speaker element is mounted to the mounting unit in the housing while a side of the diaphragm is a side to be mounted to the mounting unit in the housing and a side of the driving unit is opened.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    The present application claims priority from Japanese Patent Application No. JP 2009-256072 filed in the Japanese Patent Office on Nov. 9, 2009, the entire content of which is incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to an electronic device, such as a still camera or a video camera with a built-in speaker element. 
         [0004]    2. Description of the Related Art 
         [0005]    As shown in  FIG. 7 , a small-sized digital still camera  100  has an approximately rectangular camera body  101  that is thinned and small-sized. This camera body  101  is provided with a lens unit  102  at one of upper front corners and is provided with a shutter button  103  on the other side on an upper surface. In the digital still camera  100 , a CMOS sensor or a CCD element is used as an imaging element. The digital still camera  100  receives an imaging light, collected by the lens unit  102  at a timing of the shutter button  103  being pressed, with the imaging element and generates image data. In the digital still camera  100 , a video image can also be taken, and in this case, it is also possible to record audio by a built-in microphone in addition. When the taken video image data is replayed, a video image is displayed on a display unit on a backside of the camera body  101  and audio is emitted from a built-in speaker element. 
         [0006]    The digital still camera  100  generally uses a dynamic speaker for the speaker element. In such a dynamic speaker, a diaphragm is mounted to a bobbin of a voice coil to make a driving unit together with a magnetic circuit unit. Accordingly, power supply to the voice coil is carried out not from the diaphragm side but from the driving unit side via a flexible wiring board, a harness, and the like. 
         [0007]    For example, in the digital still camera  100  shown in  FIG. 7 , sound bores  104  are formed near the shutter button  103  on the upper surface of the camera body  101 , and a speaker element  105  is mounted inside the sound bores  104 . Specifically, as shown in  FIG. 8 , the camera body  101  has a front panel  111 , a back panel  112 , and a middle panel  113  that construct a housing, and they are coupled in such a manner that the front panel  111  and the back panel  112  sandwich the middle panel  113 . In a portion of the front panel  111  to make the upper surface of the camera body  101 , the sound bores  104  are formed. In the middle panel  113 , a mounting recess  114  is formed to mount the speaker element  105  so as to be inserted. In the mounting recess  114 , a cylindrical unit  115  is formed that continues to the mounting recess  114  and touches an area surrounding the sound bores  104 . 
         [0008]    The dynamic speaker emits antiphase sound from both a forward face and a rear face of a diaphragm  105   a . In the dynamic speaker, a driving unit  105   b  formed of a magnetic circuit unit and a voice coil is provided on the rear face side of the diaphragm  105   a  and a wiring is provided for power supply to the voice coil. Accordingly, the rear face side of the diaphragm has a complex shape and has a structure of not being easily sealed. In a mounting structure of the speaker element  105  shown in  FIG. 8 , the sealed structure on the rear face side of the diaphragm  105   a  becomes incomplete. With that, in the mounting structure of the speaker element  105  shown in  FIG. 8 , by providing the cylindrical unit  115  in the area surrounding the sound bores  104 , a sound channel is sealed and prevents cancelling with a sound from the rear face and lowering of the sound pressure. 
         [0009]    However, providing the cylindrical unit  115  in a small-sized and thinned electronic device, such as the digital still camera  100  shown in  FIG. 7 , turns out to interrupt further small-sizing of the entire device. Since the rear face side of the diaphragm  105   a  is also provided with the driving unit  105   b  and the wiring of the diaphragm  105   a , it is difficult to be provided with the sealed structure of the rear face side of the speaker element  105 . Therefore, it turns out to cause lowering of the sound pressure. 
         [0010]    Providing the sound bores  104  in the camera body  101  also turns out to limit planning of an appearance, that is, design of the entire digital still camera  100 . 
         [0011]    Japanese Unexamined Patent Application Publication No. 2007-258198 is an example of related art. 
       SUMMARY OF THE INVENTION 
       [0012]    It is desirable to provide an electronic device with a built-in speaker element to which a speaker element can be easily mounted and also that can prevent lowering of a sound pressure even when a device body is small-sized. 
         [0013]    An electronic device according to an embodiment of the present invention includes a speaker element having a diaphragm and a driving unit that vibrates the diaphragm; a mounting unit, in a housing, to which the speaker element is mounted; and an enclosure formed next to the mounting unit. The speaker element is mounted to the mounting unit in the housing while a side of the diaphragm is a side to be mounted to the mounting unit in the housing and a side of the driving unit is opened. 
         [0014]    According to an embodiment of the present invention, a speaker element is mounted to a mounting unit in a housing, where a diaphragm side thereof is a side to be mounted to the mounting unit in the housing and a driving unit side thereof is opened. A general speaker element has an identical height on the outer periphery of the diaphragm. Accordingly, the side of the diaphragm can be easily mounted without providing the enclosure with a gap. Since there is no gap, the sound from the driving unit side is not cancelled by the antiphase sound from the diaphragm side and the lowering of the sound pressure can be prevented. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1  is a perspective view, taken from the front, of a digital still camera to which an embodiment of the present invention is applied and illustrates a state of a lens cover being open; 
           [0016]      FIG. 2  is a plan view of a digital still camera to which the embodiment of the present invention is applied in a state of removing a lens cover; 
           [0017]      FIG. 3  is a cross-sectional view of a speaker element; 
           [0018]      FIG. 4  is an exploded perspective view of a mounting structure of a speaker; 
           [0019]      FIG. 5  is a cross-sectional view of the mounting structure of the speaker; 
           [0020]      FIG. 6  is a plan view of the mounting structure of the speaker; 
           [0021]      FIG. 7  is a perspective view of a digital still camera of related art; and 
           [0022]      FIG. 8  is a cross-sectional view of a mounting structure of a speaker of related art. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0023]    A description is given below to a digital still camera  1  to which an electronic device according to an embodiment of the present invention is applied with reference to the drawings. Hereinafter, the digital still camera  1  may also be referred to simply as a camera  1 . In the section of the description of the preferred embodiments, a description is given in accordance with the following order to application examples of embodiments of the present invention.
       (1) Construction of Digital Still Camera   (2) Description of Speaker Element   (3) Mounting Structure of Speaker Element   (4) Effect of Application to Digital Still Camera   (5) Modifications       
 
       (1) Construction of Digital Still Camera 
       [0029]    As shown in  FIG. 1 , the camera  1  to which an embodiment of the present invention is applied has an approximately rectangular camera body  11  that is thinned and small-sized. The camera body  11  is provided with a lens unit  12  at one of upper front corners and a shutter button  13  on the other side of the upper surface. The camera  1  uses a CMOS sensor or a CCD element as an imaging element. The digital still camera  1  receives an imaging light, collected by the lens unit  12  at a timing of the shutter button  13  being pressed, with the imaging element and generates image data. It is also possible to take a video image with the digital still camera  1 , and in this case, it is additionally possible to record audio by a built-in stereo microphone  14 . When the taken video image data is replayed, a video image is displayed on a display unit  19  (refer to  FIG. 5 ), such as an LCD and an organic electroluminescence device, on a backside of the camera body  11  and the audio is emitted from a built-in speaker element  21 . 
         [0030]    As shown in  FIG. 1 , the forward face of the camera body  11  on which the lens unit  12  is provided has a lens cover  15  mounted thereto to open and close the lens unit  12 . The lens cover  15  is formed of a flat plate in the size of covering at least half or more of the forward face of the camera body  11  or in the size capable of covering the lens unit  12 . The lens cover  15  slides vertically (directions of arrows A and B in  FIG. 1 ) relative to the camera body  11 . The lens cover  15  is, when not used, slid in the direction of the arrow A in  FIG. 1 , blocking the lens unit  12 , to block the lens unit  12 . The lens cover  15  is, when used, slid in the direction of the arrow B in  FIG. 1  to open the lens unit  12  and make it in a state capable of imaging. 
         [0031]    As shown in  FIGS. 1 ,  2 , and  5 , the camera body  11  constructs a housing by coupling a front panel  16  and a back panel  17 . The housing has built-in electronic components, such as an imaging element, a primary cell or a secondary cell, a speaker element, a microphone, an electronic flash, a display element (such as an LED and an organic electroluminescence device), a printed circuit board, and an installation device for an external storage medium. The lens cover  15  mentioned above is mounted to the front panel  16 . 
         [0032]    In the front panel  16 , as shown in  FIG. 2 , one or a plurality of openings  18  is formed. The lens cover  15  is mounted slidably via the opening(s)  18  relative to a frame disposed in the housing. Specifically, in the frame in the housing, a guide piece is formed along the directions of moving the lens cover  15 . The guide piece faces outside from the opening(s)  18  of the front panel  16 . Meanwhile, in a back face of the lens cover  15 , a guide groove is formed that is engaged to the guide piece of the frame in the housing. The lens cover  15  slides vertically (the directions of the arrows A and B in  FIG. 1 ) to the camera body  11  by relatively engaging the guide piece on the housing side to the guide groove on the back face of the lens cover  15 . The frame in the housing and the back face of the lens cover  15  are linked with an inverting member that inverts a bias direction of a toggle spring or the like. The lens cover  15  is designed to slide by the bias force of the inverting member according to a direction of operation when operated to slide, and thus the operability is improved. The camera body  11  is thinned by providing a sliding mechanism for the lens cover  15  as above at a portion of the opening(s)  18  of the front panel  16 . 
         [0033]    As described above, the camera body  11  is mounted to the forward face of the lens cover  15 , which is a movable component, and a minute void is formed between the front panel  16  and the lens cover  15  for sliding the lens cover  15 . In the camera body  11 , the inside of the housing is in communication with the outside via the minute void and the opening(s)  18  of the front panel  16 . The sound outputted from the speaker element  21  built in the housing is emitted outside the camera body  11  via such a minute void. 
       (2) Description of Speaker Element 
       [0034]    The camera body  11  has a built-in speaker element  21  to emit audio data, replayed in synchronization with operation sound data and video image data, near an approximate center of the upper surface side of the camera body  11  provided with the shutter button  13  and the like. As shown in  FIG. 3 , the speaker element  21  has a frame  22  formed with a convex cross-section. The frame  22  has a protrusion  22   a  constructing a space to dispose a driving unit of the speaker element  21 . The frame  22  hangs over outwardly in a flange shape so as to continues to the protrusion  22   a  and has an opening  22   b  having a larger diameter than the protrusion  22   a.    
         [0035]    In the protrusion  22   a , a magnet  23  is disposed that constructs a magnetic circuit unit and also a top plate  24  is disposed on the magnet  23 . The frame  22  and the top plate  24  also become a yoke. A magnetic gap  25  is formed between an outer periphery surface of the top plate  24  and approximately orthogonal corner portions to make a border of the protrusion  22   a  and the opening  22   b . A voice coil  26  is disposed in the magnetic gap  25 . On an outer surface at the hanging portion of the frame  22 , that is, on a surface of the protrusion  22   a  side, a terminal  27  is formed. The terminal  27  is electrically connected to an end of the voice coil  26 , and further, is electrically connected to terminal units of a driving circuit of an external speaker and a wiring board, such as a flexible wiring board, by solder, a conductive adhesive, or the like. 
         [0036]    In the opening  22   b  of the frame  22 , a step  28   a  is formed in the middle of the height and an outer periphery of a diaphragm  28  is fixed to the step  28   a  with an adhesive or the like. The middle portion of the diaphragm  28  is fixed to a tip end of the voice coil  26  with an adhesive or the like. Further, a frame cover  29  is fixed to the step  28   a  so as to cover the opening  22   b . Further, a net packing  30  is fixed to an opening end of the opening  22   b . The net packing  30  is not strictly desired. In such a manner, the speaker element  21  has an identical height on the opening  22   b  side of the frame  22 . 
         [0037]    In the speaker element  21 , one or a plurality of sound bores  31  are formed in the portion of the frame  22  hanging over from the protrusion  22   a . In the speaker element  21 , a driving current corresponding to an inputted audio signal is supplied to the voice coil  26 , thereby vibrating the diaphragm  28  to generate a sound. The sound bore(s)  31  enable the sound generated in the diaphragm  28  to be emitted from the protrusion  22   a  side of the frame  22 . 
       (3) Mounting Structure of Speaker Element 
       [0038]    The camera body  11  has a built-in speaker element  21 , near the approximate center of the upper surface side of the camera body  11  on which the shutter button  13  and the like are provided, that emits audio data to be replayed in synchronization with the operation sound data and the video image data. As shown in  FIGS. 4 through 6 , the speaker element  21  has a mounting structure in which a component mounting member  41  of a mold component disposed in the housing constructing the camera body  11  is provided with a mounting unit  42  of the speaker element  21 . The mounting unit  42  is a recess having an approximate size of inscribing the speaker element  21  and the speaker element  21  has the opening  22   b  side disposed on a bottom surface side of the recess. The bottom surface of the mounting unit  42  is a slope  43  and is tilted to face an upper forward face of the camera body  11 . In the slope  43 , a communication bore  44  is formed that is in communication with an enclosure  45  formed adjacent to a back side of the slope  43 . The shape of the mounting unit  42  is not strictly desired to be a recess. In the embodiment of the present invention, the bottom surface of the mounting unit  42  may also be a plane vertical to a side wall, not a slope. 
         [0039]    As shown in  FIG. 5 , the enclosure  45  is formed on the back face of the slope  43  so as to make, for example, an approximate triangular cross section. The enclosure  45  is blocked by a plate member  49  having a bottom surface thereof formed of a sheet metal, a resin plate, and the like. The enclosure  45  here has a content of, for example, approximately 1 cc. Thus, a sealed space is formed in the enclosure  45 . In the enclosure  45 , the sealed space may also be constructed without using the plate member  49  but only with the component mounting member  41 . 
         [0040]    The speaker element  21  is disposed in the recess of the mounting unit  42  to have the opening  22   b  side facing the bottom surface side of the recess. In this case, the space of the mounting unit  42  has the bottom surface as the slope  43  and is formed in an approximate triangular cross section, and the speaker element  21  is arranged obliquely. Accordingly, a space for storing the speaker element  21  can be smaller than a space of a rectangular that is a flattened bottom surface. That is, the speaker element  21  is arranged in a smaller space. 
         [0041]    When the speaker element  21  is mounted to the mounting unit  42 , the speaker element  21  has the frame  22  side facing upwardly and obliquely. In the speaker element  21 , the sound bore(s)  31  are formed in the frame  22  and the generated sound is emitted from the sound bore(s)  31 . 
         [0042]    The speaker element  21  mounted to the mounting unit  42 , as shown in  FIGS. 5 and 6 , is subsequently supported elastically by an elastic support piece  47  formed in a support plate  46  to fix various components in the camera body  11 . The support plate  46  is formed by punching out a sheet metal, for example. The elastic support piece  47  is formed by punching out an area surrounding the elastic support piece  47  of the support plate  46  and presses the speaker element  21  to the slope  43  for support by an elastic force that is approximately vertical to the slope  43 . Thus, the speaker element  21  is fixed to the recess of the mounting unit  42 . The support plate  46  is positioned by being engaged to a positioning lug  46   a  of the component mounting member  41  near the elastic support piece  47 . 
         [0043]    Further, the speaker element  21  may also be fixed to the slope  43  using an adhesive or the like. 
         [0044]    As shown in  FIGS. 4 and 6 , a flexible wiring board  48  electrically connected to the terminal  27  is disposed along an area surrounding the protrusion  22   a  on the back face of the frame  22  of the speaker element  21 . At this point, the flexible wiring board  48  is mounted so as to avoid the sound bore(s)  31  of the frame  22  not to block the sound bore(s)  31 . 
         [0045]    In the flexible wiring board  48 , in a case of overlapping the sound bore(s)  31  when disposed along the area surrounding the protrusion  22   a , a notch or a through hole turns out to be formed to expose the sound bore(s)  31  to the outside. 
         [0046]    In the mounting structure of the speaker element  21  shown in  FIGS. 4 through 6 , a space of an approximate cube or an approximate rectangular parallelepiped is sectioned by the slope  43  into two in an approximate triangular cross section shape. Accordingly, this mounting structure is capable of defining one as the mounting unit  42  to mount the speaker element  21  and the other as the enclosure  45  for a space-saving speaker system. 
         [0047]    The speaker element  21  is mounted in such a manner that the opening  22   b  of the frame  22  on the diaphragm  28  side is pressure contacted to the slope  43 . The speaker element  21  has the diaphragm  28  side, that is, the opening  22   b  formed in an identical height and having a shape simpler than that of the protrusion  22   a  side. Accordingly, the speaker element  21  can be mounted easily to the slope  43  as the shape of the opening  22   b  is simple. Since the speaker element  21  is easily attached firmly to the flattened slope  43  without a gap, the opening  22   b  side and the protrusion  22   a  side can be separated securely with the diaphragm  28  as a border. Accordingly, in this speaker system, the degree of sealing the space on the enclosure  45  side becomes high. Accordingly, the sound emitted from the frame  22  side of the speaker element  21  is emitted from the sound bore(s)  31  of the frame  22  to the outside, that is, into the camera body  11  without being cancelled by an antiphase sound on the opening  22   b  side, that is, without causing lowering of the sound pressure. 
         [0048]    Results of comparative experiments is shown below regarding sound pressures in the mounting structure of the speaker element to which the embodiment of the present invention shown in  FIGS. 4 through 6  is applied (the embodiment of the present invention) and the mounting structure of the speaker element shown in  FIG. 8  (a related art structure  1 , a related art structure  2 ). The embodiment of the present invention has a speaker element with a diameter of 8 φ, which is smaller than those of the related art structures  1  and  2  of 10 φ. 
         [0000]    
       
         
               
               
               
               
             
               
               
               
               
             
           
               
                   
                   
               
               
                   
                 600 Hz 
                 1 kHz 
                 3 kHz 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Related art structure 1 
                 30.5 dB 
                 52.0 dB 
                 63.5 dB 
               
               
                 Related art structure 2 
                 32.0 dB 
                 53.0 dB 
                 63.5 dB 
               
               
                 Embodiment of present invention 
                 31.5 dB 
                 50.5 dB 
                 62.0 dB 
               
               
                   
               
             
          
         
       
     
         [0049]    From the results above, it is possible to confirm that the mounting structure of the speaker element to which the embodiment of the present invention shown in  FIGS. 4 through 6  is applied can have a sound pressure level of a similar degree to that of the related art structures  1  and  2  even when the diameter of the speaker element is smaller. 
         [0050]    In the embodiment of the present invention, the direction to mount the speaker element  21  to the slope  43  is not limited to the case of facing the upper forward face of the camera body  11  and it may also face, for example, a lower forward face of the camera body  11  or further another direction. 
       (4) Effect of Application to Digital Still Camera 
       [0051]    As shown in  FIGS. 1 and 2 , the lens cover  15 , which is a movable component, is mounted to the forward face of the camera body  11 . Between the front panel  16  and the lens cover  15 , a minute void for sliding the lens cover  15  is formed. In the camera body  11 , the inside of the housing and the outside are in communication via the minute void and the opening(s)  18  of the front panel  16 . The sound emitted from the sound bore(s)  31  of the speaker element  21  built in the housing is emitted outside the camera body  11  via the opening(s)  18  or the minute void between the lens cover  15  and the front panel  16 . The sound bore(s)  31  formed in the frame  22  of the speaker element  21  faces the forward face side of the camera body  11  to which the lens cover  15  is mounted. Accordingly, the sound emitted from the sound bore(s)  31  is efficiently emitted outside the camera body  11  via the opening(s)  18  and the minute void between the lens cover  15  and the front panel  16 . 
         [0052]    As described above, the sound emitted by the speaker element  21  is emitted outside the camera body  11  mainly via the opening(s)  18  and the minute void between the lens cover  15  and the front panel  16 . Other than that, the sound emitted by the speaker element  21  is emitted outside the camera  1  also from a minute void formed in a portion of coupling the front panel  16  and the back panel  17  and the like. 
         [0053]    In such a manner, in the camera  1 , the sound from the speaker element  21  is emitted via the minute voids created for mounting the lens cover  15 , which is a movable component. Accordingly, the camera  1  is provided without the sound bores  104  provided in the camera body  101 , as in the digital still camera  100  of related art, and can enhance the flexible planning of design. 
       (5) Modifications 
       [0054]    Although the description is given above to an example of the digital still camera  1  to which the embodiment of the present invention is applied, an electronic device using a mounting structure of the speaker element  21  to which the embodiment of the present invention is applied may also be another imaging device, such as a compact video camera. It may also be an information processing device, such as a compact personal computer. 
         [0055]    It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.