Patent Publication Number: US-2006005354-A1

Title: Hinge device, hinge unit and electronic appliance

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
      This is a Continuation Application of PCT Application No. PCT/JP03/16963, filed Dec. 26, 2003, which was published under PCT Article 21(2) in Japanese.  
      This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2002-381871, filed Dec. 27, 2002, the entire contents of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      This invention relates to a hinge device and a hinge unit for freely rotatably linking a first member and a second member for an electronic appliance and also to an electric appliance comprising such a hinge device.  
      2. Description of the Related Art  
      Jpn. Pat. Appln. KOKAI No. 8-22343 discloses an information processing apparatus comprising a display section and an operation section (keyboard section) that are liked to each other by means of a hinge section as in the case of a note type personal computer, the hinge section containing an image pickup optical system, a lens section being arranged at an end thereof.  
      Jpn. Pat. Appln. KOKAI No. 2001-169166 discloses a portable terminal apparatus comprising a main body section and a flip section including a monitor screen that are linked to each other by means of a freely rotatable shaft section, an image pickup lens being arranged in the longitudinal direction in the shaft section.  
     BRIEF SUMMARY OF THE INVENTION  
      According to a first aspect of the present invention, there is provided a hinge device for an electronic appliance for rotatably linking a first member and a second member, comprising: 
          a bearing section arranged on one of the first member and the second member; and     a rotary shaft section arranged on the other of the first member and the second member,     the rotary shaft section being rotatably engaged with the bearing section, and     the rotary shaft section being provided with a hollow section configured to arrange a functional member relating to a function of the electronic appliance to which the hinge device is applied.        

      According to a second aspect of the present invention, there is provided a hinge unit for an electronic appliance for rotatably linking a first member and a second member, comprising: 
          a bearing section arranged on one of the first member and the second member;     a rotary shaft section arranged on the other member, the rotary shaft section being rotatably engaged with the bearing section;     a hollow section arranged on the rotary shaft section; and     a functional member relating to a function of the electronic appliance to which the hinge device is applied, the functional member being arranged in the hollow section.        

      According to a third aspect of the present invention, there is provided an electronic appliance comprising: 
          a main body section provided with an operating section;     an overlying section provided with a display section; and     a hinge device adapted to link the main body section and the overlying section so as to lay the overlying section on the operating section so as to cover the operating section while the operating section being not in use but expose the operating section by rotating the overlying section from the overlying position relative to the operating section, wherein     the hinge device includes a bearing section arranged on one of the main body section and the overlying section and a rotary shaft section arranged on the other section, the rotary shaft section being rotatably engaged with the bearing section; and     the rotary shaft section is provided with a hollow section configured to arrange a functional member relating to a function of the electronic appliance.        

      Advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING  
      The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention.  
       FIG. 1  is a schematic cross sectional view of a first embodiment of hinge device according to the invention;  
       FIG. 2  is a schematic lateral view of the hinge device of  FIG. 1  in a state where the spring and the E-ring thereof are removed;  
       FIG. 3  is a schematic cross sectional view of a second embodiment of hinge device according to the invention;  
       FIG. 4  is a schematic cross sectional view of a camera unit illustrated as an example of functional member relating to a function of an electronic appliance;  
       FIG. 5  is a schematic view of the camera unit of  FIG. 4  as seen from the side of the lens surface;  
       FIG. 6  is a schematic cross sectional view of the spacer of the camera unit;  
       FIG. 7  is a schematic cross sectional view of a first embodiment of hinge unit according to the invention that is realized by using the first embodiment of hinge device;  
       FIG. 8  is a schematic cross sectional view of the first embodiment of hinge unit according to the invention that is realized by using the second embodiment of hinge device;  
       FIG. 9  is a schematic plan view of the light receiving section of the image sensor, showing the dimensions thereof;  
       FIG. 10  is a schematic cross sectional view of a second embodiment of hinge unit according to the invention;  
       FIG. 11  is a schematic cross sectional view of a third embodiment of hinge device and a third embodiment of hinge unit according to the invention, illustrating the configuration thereof;  
       FIG. 12  is a schematic perspective view of a first embodiment of electronic appliance according to the invention, showing its appearance;  
       FIG. 13  is a schematic perspective view of the pivot section of the embodiment of  FIG. 12 ;  
       FIG. 14  is a schematic perspective view of a second embodiment of electronic appliance according to the invention, which is a foldable portable phone equipped with a camera unit in a state of being ready for use;  
       FIG. 15  is an exploded schematic perspective view of a hinge unit according to the invention, illustrating how it is assembled;  
       FIG. 16  is a schematic perspective view of the hinge unit of  FIG. 15  that is assembled;  
       FIG. 17  is a schematic cross sectional view of a fourth embodiment of hinge device and a fourth embodiment of hinge unit according to the invention, illustrating the configuration thereof;  
       FIG. 18  is a schematic partial cross sectional view of a fifth embodiment of hinge device according to the invention, illustrating the configuration thereof;  
       FIG. 19  is a schematic cross sectional view of a sixth embodiment of hinge device and a sixth embodiment of hinge unit according to the invention, illustrating the configuration thereof;  
       FIG. 20  is a schematic cross sectional view of the embodiment of  FIG. 19 , showing the view angle thereof when the conversion lens is removed;  
       FIG. 21  is a schematic cross sectional view of a seventh embodiment of hinge device and a seventh embodiment of hinge unit according to the invention, illustrating the configuration thereof; and  
       FIG. 22  is a schematic perspective view of the hinge device and the hinge unit of  FIG. 21 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      Now, preferred embodiments of the present invention will be described by referring to the accompanying drawings.  
     First Embodiment of Hinge Device  
      As shown in  FIG. 1 , in this embodiment of hinge device, a bearing  10  is rotatably fitted onto a hollow shaft  12 . A cam plate  14  is also fitted onto the hollow shaft  12 .  
      As shown in  FIG. 2 , the cam plate  14  is a substantially circular plate-shaped member that is provided with cam sections  14 A formed thereon. The cam sections  14 A may have an axially convex profile. The cam plate  14  has a revolution restricting section  14 B in a small diameter area thereof. The hollow shaft  12  is formed to show a profile corresponding to that of the revolution restricting section  14 B. With this arrangement, the hollow shaft  12  and the cam plate  14  are combined in such a way that they cannot rotate but are axially movable relative to each other.  
      On the other hand, though not shown, the bearing  10  is provided with a number of cam facets on the surface thereof located vis-à-vis the cam plate  14  so as to be engaged with each other. The cam facets formed on the bearing  10  are arranged at predetermined positions that make them to be engaged with the corresponding surface of the cam plate  14  as the hollow shaft  12  and the bearing  10  revolve relative to each other.  
      A spring  16  is arranged around the hollow shaft  12  in a compressed state relative to its free length in such a way that it can be compressed and expanded. The spring  16  is restricted against expansion at an end thereof by the cam plate  14  and at the opposite end by an E-ring  18  fitted to the hollow shaft  12  as anti-release member for the spring  16 . Therefore, the cam plate  14  is pressed against the bearing  10  by the spring  16 . While the spring  16  is a coil spring in this embodiment, it may alternatively be a coned disk spring. A coned disk spring may be used for the cam plate itself.  
      Thus, as long as the cam sections  14 A of the cam plate  14  and the cam facets (not shown) formed on the bearing  10  are engaged with each other, they are restricted against revolution.  
      As a user applies force to make the hollow shaft  12  and the bearing  10  revolve relative to each other, the cam sections  14 A of the cam plate  14  and the cam facets formed on the bearing  10  are subjected to the force trying to disengage them from each other. As a result, the cam plate  14  is driven to move against the spring force of the spring  16  in the leftward direction in  FIG. 1 .  
      As the hollow shaft  12  and the bearing  10  are forced to revolve further, the cam plate  14  and the bearing  10  are driven to revolve relative to each other against the frictional force generated by the resilience of the spring  16 . As the cam sections  14 A approach the respective next cam facets formed on the bearing  10 , they are drawn to each other so as to become engaged with each other without any external force trying to revolve them further because of the cam effect. The cam plate  14  and the bearing  10  are brought into a stabilized state when the cam sections  14 A and the respective next cam facets are engaged with each other. The engagement and the disengagement of the cam give a sensation of click to the user.  
      Since the cam plate  14  is axially movable relative to the hollow shaft  12 , the hollow shaft  12  and the bearing  10  do not move axially relative to each other if a sensation of click is generated when the hollow shaft  12  and the bearing  10  are forced to revolve relative to each other.  
      The above-described axial movement is reversible. The stabilized engagement position of the cam and the feeling of operation that involves the above-described sensation of click are defined by the specifications of the electronic appliance for which the hinge device is used. Then, the spring force, the cam profile and the cam position are defined accordingly.  
      Sleeve  20  is provided with slits or grooves (not shown) on the inner wall surface thereof that are to be engaged with the cam sections  14 A of the cam plate  14  in order to make the sleeve  20  not revolvable relative to the cam plate  14 . It is arranged around the spring  16  and held in position by the anti-release E-ring  18 . It may be needless to say that the slits are arranged axially at regular intervals so as to not obstruct any axial movement of the cam plate  14 . With the above-described arrangement, the sleeve  20  cannot revolve relative to the hollow shaft  12  by way of the cam plate  14 .  
      By forming a hinge device having a click mechanism around the hollow shaft  12 , it is possible to contain one or more than one functional members relating to certain functions of the electronic appliance, for which the hinge device is used, in the hollow shaft  12 . In other words, the radial and axial spaces of the rotary shaft of the appliance can be effectively exploited.  
     Second Embodiment of Hinge Device  
      The second embodiment of hinge device according to the invention is realized without using a cam plate.  
      As shown in  FIG. 3 , a bearing  22  is fitted to a hollow shaft  24  in such a way that the bearing  22  can rotate around and move axially relative to the hollow shaft  24  in this embodiment of hinge device. Additionally, hollow shaft  24  is provided with cam sections  24 A, while the bearing  22  is also provided with cam sections  22 A at appropriate positions where they are engaged with the respective cam sections  24 A. A spring  26  is arranged around the hollow shaft  24  and anchored by an E-ring  28  so as to press the bearing  22 . The E-ring  28  and a sleeve  30  are arranged in such a way that both of them cannot revolve relative to the hollow shaft  24 . More specifically, it is sufficient for the E-ring  28  and the sleeve  30  to be unable to revolve relative to the hollow shaft  24  and the E-ring  28  respectively. Although not shown, they may be provided with respective anti-revolution sections that are engaged with each other in order to make them unable to revolve relative to each other.  
      With the above-described arrangement, as the bearing  22  is driven to revolve relative to the hollow shaft  24 , the cam is disengaged when the bearing  22  is moved axially against the resilience of the spring  26 . Otherwise, the hinge device of this embodiment operates same as the hinge device of the first embodiment.  
     First Embodiment of Hinge Unit  
       FIGS. 4 and 5  illustrates a functional member of an electronic appliance, which is a camera unit having one of the functions of the electronic appliance. The camera unit comprises a lens group  32 , an image sensor  34 , a lid plate  36  and a lens barrel  38 . The lens group  32  forms an image of the object of shooting on the image sensor  34 . The image sensor  34  converts the image into electric data. The lid plate  36  is a substrate on which the image sensor  34  is mounted. The lens barrel  38  takes a role of holding the lens group  32  and the image sensor  34  at respective predetermined positions. The lens barrel  38  has a diaphragm  38 A. Although not shown, the lens barrel  38  may be formed by combining a lens holding section, a diaphragm, a sensor holding section and so on.  
      The camera unit is produced by rigidly bonding the lens barrel  38  and the lid plate  36  to each other, rigidly fitting the lens group  32  to the lens barrel  38  by a predetermined means and mounting the image sensor  34  on the lid plate  36 . While the lid plate  36  and the lens barrel  38  are rigidly bonded to each other in the above description, the lens barrel  38  and the image sensor  34  may alternatively and directly be fixed to each other. Although not shown, it may be needless to say that wires connecting the camera unit to the electronic appliance, on which camera unit is mounted, are extended from the lid plate  36 .  
      As shown in  FIG. 6 , a spacer  40  may have to be arranged in the hollow shaft  12  of the hinge device of the first or second embodiment in order to mount the camera unit, which is a functional member, in the hinge device. In other words, the camera unit may be mounted in the internal space of the hollow shaft  12  other than the space that is limited by the spacer  40 . Each of the spacer  40  and the camera unit may be mounted in the hinge device by bonding, by means of screws, by press fit or the like. Of course, the spacer  40  and the hollow shaft  12  may be formed integrally. The use of a spacer  40  provides an advantage that any of various functional members may be mounted in the hollow shaft  12  by selecting an appropriately shaped spacer  40  in accordance with the external profile of the functional member.  
      Thus, as shown in  FIG. 7 , the hinge unit of the first embodiment is realized by mounting the camera unit, which is a functional member as shown in  FIGS. 4 and 5 , in the inside of the hollow shaft  12  of the hinge device that contains a spacer  40  in it so as to unitize the camera unit and the hinge device.  
      While  FIG. 7  illustrates the hinge unit of the first embodiment according to the invention that is realized by using the hinge device of the first embodiment,  FIG. 8  illustrates the hinge unit of the first embodiment according to the invention that is realized by using the hinge device of the second embodiment as shown in  FIG. 3 .  
      Thus, the hinge unit of the first embodiment can improve the efficiency of utilizing the space of an electronic appliance, the feeling of ease of operation of opening and closing the electronic appliance and the efficiency of assembling the electronic appliance and also downsize the electronic appliance because the shaft of the hinge section for opening and closing the cabinet is provided with a hollow section and a functional member of the electronic appliance, for which the hinge is used, is contained in the hollow section.  
     Second Embodiment of Hinge Unit  
      The hinge unit of the second embodiment according to the invention is realized by arranging the image sensor  34  of the camera unit that is arranged in the hollow shaft  12  of the above described hinge device of the first or second embodiment to the outside of the hollow shaft  12  and combined with the hinge device.  
      As shown in  FIG. 9 , the image sensor  34  comprises a light receiving section  34 A that includes a large number of light receiving elements and a processing section arranged around the light receiving section  34 A for the purpose of transmitting the electric signal from the light receiving section  34 A to the downstream. Additionally, the hinge unit requires a lid plate  36  that operates as substrate for mounting the image sensor  34  thereon. Thus, from the viewpoint of optical design, the diameter of an image sensor section as a combination of the image sensor  34  and the lid plate  36  is greater than the outer diameter of the lens required for focusing an image on the light receiving section  34 A.  
      Thus, the diameter of the hollow shaft  12  of the hinge device is defined by the outer diameter of the lens when the image sensor section is arranged outside the hollow shaft  12  of the hinge device. Then, as a result, it is possible to reduce the external dimensions of the hinge unit comprising a camera unit.  
      It will be clear by comparing  FIG. 7  illustrating the hinge unit of the first embodiment and  FIG. 10  illustrating the hinge unit of this embodiment that the hinge unit of this embodiment shows a smaller outer diameter of the hinge device although it combines a hinge device and a camera unit that are same as those of the hinge unit of the first embodiment.  
     Third Embodiment of Hinge Device and Third Embodiment of Hinge Unit  
      Now, the third embodiment of hinge device and the third embodiment of hinge unit according to the invention will be described below. In the hinge unit of this embodiment, the hollow shaft of the hinge device of the first or second embodiment is made to operate also as the lens barrel of the camera unit.  
      As shown in  FIG. 11 , the lens barrel  42  of the camera unit typically takes the role of the hollow shaft  12  of the hinge device of  FIG. 1 .  
      As a result of arranging the lens group  32  directly in the hollow shaft in this way, it is possible to further reduce the diameter of the hinge unit.  
     First Embodiment of Electronic Appliance  
      Now, the first embodiment of electronic appliance according to the invention will be described below. The first embodiment of electronic appliance according to the invention is a foldable and portable telephone set that is equipped with a camera unit. Of course, the conceivable field of application of electronic appliance according to the invention includes not only foldable and portable telephone sets but also note type personal computers, portable information terminals, digital cameras and other apparatus comprising two cabinets that are linked to each other by means of a hinge device and can be opened and closed relative to each other.  
      As shown in  FIG. 12 , the portable telephone set comprises an upper cabinet  44 , which is a first member having a display section  44 A such as an LCD, and a lower cabinet  46 , which is a second member having switches  46 A that operate as keys of a keyboard, the upper cabinet  44  and the lower cabinet  46  being linked to each other by means of a rotary shaft  48  so as to be folded and opened relative to each other.  
       FIG. 13  illustrates the configuration of a pivot section. As shown in  FIG. 13 , a shaft section  46 B of the lower cabinet  46  is provided on the inner periphery thereof with a projection  46 C. The hinge device, or the hinge unit, of any of the first through third embodiments is provided on the sleeve  50  thereof, which corresponds to the above described sleeve  20 , with a recess  50 A having a profile that matches the projection  46 C of the shaft section  46 B. Thus, the shaft section  46 B and the hinge device, or the hinge unit, revolve together. Although not shown, the shaft section  46 B has an axial aperture for exposing the functional member mounted in the hinge device.  
      Although not shown specifically, the hinge device, or the hinge unit, is provided at the opposite side thereof with a recess  52 A having a profile that matches the projection (not shown) arranged on the shaft section  44 B of the upper cabinet  44  so as to make the bearing  52 , which corresponds to the above described bearing  10 , engage and revolve together with the shaft section  44 B of the upper cabinet  44 .  
     Second Embodiment of Electronic Appliance  
      Now, the second embodiment of electronic appliance according to the invention will be described below. The second embodiment of electronic appliance according to the invention is a foldable and portable telephone set that is equipped with a camera unit.  
      As shown in  FIG. 14 , the portable telephone set comprises a lower cabinet  54  and an upper cabinet  56  having a display section  56 , the lower cabinet  54  and the upper cabinet  56  being linked to each other by means of the hinge unit of any of the first through third embodiments having a cabinet opening/closing rotary shaft  58 A and an upper cabinet rotary shaft  58 B. As pointed out above, the camera unit  60  is mounted in the hollow shaft of the hinge device of any of the first through third embodiments.  
      When the functional member mounted in the hinge device is a camera unit, the user generally holds the lower cabinet  54  in a manner as shown in  FIG. 14 . Then, the camera unit, the camera lens in particular, is preferably aligned with the holding section. Therefore, although not shown specifically, the camera unit is arranged at a predetermined position in and aligned with the hollow shaft  12  of the hinge device. This arrangement can be realized by forming a projection and a matching recess respectively on part of the end facet or the inner surface of the hollow shaft  12  and on the outside of the lens barrel  38  of the camera unit  60  in such a way that the hollow shaft  12  and the lens barrel  38  can be assembled only in a predetermined direction. This arrangement is sufficient for achieving the necessary alignment because the sleeve  20  cannot revolve relative to the hollow shaft  12  as described above by referring to the first embodiment of electronic appliance.  
      Now, the process of combining the hinge unit with the electronic appliance will be discussed by referring to  FIGS. 15 and 16 .  FIG. 15  is an exploded schematic perspective view of the hinge unit and  FIG. 16  is a schematic perspective view of the assembled hinge unit.  
      Firstly, frame  62 , which is the first member having a bearing section  62 A corresponding to the bearing  10  for instance, is fitted to the camera unit  60 . Then, a cam plate  64  that corresponds to the cam plate  14  for instance, a spring  66  that corresponds to the spring  16  for instance and a lower left frame  68  to be used for the lower cabinet as the second member having a sleeve corresponding to the above described sleeve  20 , are fitted to the camera unit  60 . Thereafter, an anti-release E-ring  70  that corresponds to the E-ring  18  for instance is rigidly secured to the camera unit.  
      Another bearing section  62 B is similarly arranged at the opposite side of the frame  62 . A hollow shaft  72  is made to run through the bearing section  62 B and the lower right frame  74  to be used for the lower cabinet is caulked. Note that the right side hinge is a hinge that does not have any click mechanism.  
      The frame  62  is provided with a cam section (not shown) that matches a rotary cam plate  76 . The rotary hollow shaft  78  is made to rotabably run through the frame  62  and then through the rotary cam plate  76 , a coned disk spring  80  and an upper cabinet frame  82 . In this way, the rotary hollow shaft  78  and the upper cabinet frame  82  are rigidly secured to each other so that they may not revolve relative to each other.  
      The upper cabinet frame  82  is fitted to the upper cabinet  56  of the electronic appliance and the lower left frame  68  to be used for the lower cabinet and the lower right frame  74  to be used for the lower cabinet are fitted to the lower cabinet  54 .  
      As a result, the upper cabinet  56  and the lower cabinet  54  of the electronic appliance can be opened and closed relative to each other by means of the hinge device having the cabinet opening/closing rotary shaft  58 A that operates as the central axis of the camera unit  60  and that of the hollow shaft  72 . The upper cabinet  56  can be rotated around its axis of revolution that agrees with the central axis of the hollow shaft  78 . The hollow shafts  72 ,  78  provide spaces for containing wire extending from various components of the electronic appliance.  
     Fourth Embodiment of Hinge Device, Fourth Embodiment of Hinge Unit and Third Embodiment of Electronic Appliance  
      The fourth embodiment of hinge device and that of hinge unit according to the invention are adapted to removably contain a functional member. The functional member of the embodiments is a conversion lens to be fitted to the front end of a camera to modify the characteristics of the lens of the camera. The conversion lens may be a close-up lens that provides the camera with a close-up feature, a wide conversion lens for modifying the view angle of the lens of the camera, a tele-conversion lens or some other lens.  
      As shown in  FIG. 17 , the hinge device of this embodiment, or the hinge unit of this embodiment, is typically fitted to the shaft section  46 B of the lower cabinet  46  and also to the shaft section  44 B of the upper cabinet  44  of an electronic appliance.  
      The hollow shaft  84  of the hinge device of this embodiment shows a profile produced by closing the aperture of the hollow shaft  12  or  24  of the hinge device of the first or second embodiment, whichever appropriate, located at the side of the bearing  10  or  22 , whichever appropriate so as to prevent the conversion lens that is formed by a lens barrel  86  and a lens  88  and contained in the hollow shaft  84  from falling into the shaft section or the inside of the electronic appliance through the aperture.  
      In the hinge device of this embodiment, or the hinge unit of this embodiment, a lid  90  is removably fitted to the shaft section  46 B of the lower cabinet  46  of the electronic appliance. The lid  90  operates to prevent the conversion lens mounted in the hollow shaft  84  of the hinge device from inadvertently falling. Although not shown, the lid  90  is devised so as not to be easily removed from the shaft section  46 B, although it is removably fitted to the shaft section  46 B.  
      If the electronic appliance of the third embodiment having the hinge unit of the above-described configuration is a portable telephone set as illustrated in  FIG. 12 , in the camera mounted in the appliance (not shown), the lens may be so arranged that its surface is exposed at the side opposite to the display section  44 A of the upper cabinet  44 . Then, the user can enjoy a wide choice of images to be shot if he or she takes out the conversion lens mounted in the hollow shaft  84  of the hinge device and attach it to the camera. Although not shown, any of various techniques including the use of a screw may be used to attach the conversion lens to the camera.  
      When a camera unit is arranged in the hinge device as in the case of the portable telephone set illustrated in  FIG. 14 , it is possible to rigidly secure the camera unit to the hinge device located at a side of the cabinet opening/closing rotary shaft  58 A and removably arrange a conversion lens in the hinge device located at the opposite side as in the case of this embodiment.  
     Fifth Embodiment of Hinge Device, Fifth Embodiment of Hinge Unit and Fourth Embodiment of Electronic Appliance  
      The hinge device of this embodiment and the hinge unit of this embodiment have a plurality of hollow sections. The electronic appliance of this embodiment comprises such a hinge device or a hinge unit.  
      More specifically, as shown in  FIG. 18 , two hinge devices of any of the first through fourth embodiments, those of the first embodiment for instance, are used to form a unified bearing  92  that operates integrally as a single hinge device.  
      With this arrangement, it is possible to partly extend the bearing  92  and form fitting holes  92 A so as to rigidly secure the bearing  92  to the cabinet of the electronic appliance without forming a recess (or a projection) that is engaged with the electronic appliance on the outer periphery of the hinge device as described above. Note that, the above-described sleeve  20  may also be provided with such a rigidly securing means.  
      With such a hinge device or a hinge unit, it is possible to arrange a camera unit and rigidly hold it in position in the hollow space as shown at the left side in  FIG. 12  and removably arrange a conversion lens as shown in  FIG. 17  in the hollow space as shown at the right side in  FIG. 12  in the electronic appliance.  
      It is also possible to provide the hinge device with a plurality of hollow spaces and arranging respective functional members therein to raise the added value of the small electronic appliance. Each of the functional members may be rigidly secured in position or removably arranged in position. Additionally, since the hinge device is integrally formed, it is adapted to be unitized to improve the efficiency of assembling the electronic appliance.  
     Sixth Embodiment of Hinge Device, Sixth Embodiment of Hinge Unit and Fifth Embodiment of Electronic Appliance  
      A functional member is rigidly arranged in one of the hollow shafts of the hinge device of this embodiment and a removable additional functional member is added to it.  
      As shown in  FIG. 19 , the hinge unit (hinge device) of this embodiment has a configuration similar to the hinge device or the hinge unit of any of the first through third embodiments, the hinge device or the hinge unit of the first embodiment for instance. However, a camera unit comprising a lens barrel  96 , a lens  98  and an image sensor section is rigidly mounted in the hollow shaft  94  thereof and a conversion lens unit comprising a different lens barrel  100  and a different lens  102  is removably mounted in the hollow shaft  94 . Although not specifically illustrated, the conversion lens unit is removably mounted by means of a screw section arranged on the inner wall surface of the hollow shaft  94  and a corresponding screw section arranged in the lens barrel  100 . The lens barrel  96  and the lens barrel  100  may be so formed as to be engaged with each other by means of a screw.  
      In this instance, the conversion lens is a wide conversion lens. With this arrangement, the camera can operate with a wide view angle  106  for the principal rays  104  as shown in  FIG. 19  when the wide conversion lens is attached. On the other hand, although partly omitted but shown in  FIG. 20 , the view angle  108  of the lens is reduced from the wide view angle  106  when the wide conversion lens is removed. In the latter case, the principal rays  104  also have to be made free from vignetting due to the hollow shaft  94 . Then, the hollow shaft  94  can operate as lens hood for preventing unnecessary rays of light from entering the camera unit.  
      Although not shown, it may be clear that the electronic appliance of the fifth embodiment can be realized by using the hinge device of this embodiment.  
     Seventh Embodiment of Hinge Device, Seventh Embodiment of Hinge Unit and Sixth Embodiment of Electronic Appliance  
      The focal point of a camera unit of the above-described type may have to be adjusted at the time of assembling the camera unit for the purpose of operating precision. This embodiment is adapted to such focal point adjustment.  
      Now, the hinge device of this embodiment and the hinge unit of this embodiment will be described by referring to  FIGS. 21 and 22 . The hollow shaft of the hinge device of this embodiment also operates as lens barrel.  
      As shown in  FIG. 21 , in this embodiment, the lens barrel of the camera unit is divided into a lens frame  110  and a sensor frame  112 . Lenses and an image sensor section are fitted respectively to the lens frame  110  and the sensor frame  112 . Subsequently, the lens frame  110  and the sensor frame  112  are put together by means of a screw section  110 A of the lens frame  110  and a screw section  112 A of the sensor frame  112 . At this time, the focal point of the camera unit is adjusted by means of the screw sections  110 A,  112 A in such a way that a sharp image of an object of shooting separated away from the camera unit by a predetermined distance image may be formed on the image sensor  34 .  
       FIG. 22  illustrates the state of the camera unit when the focal point adjustment is completed. As described earlier by referring to  FIG. 2 , the sensor frame  112  has a revolution restricting section  112 B. If the came plate  114  shown in  FIG. 21  has a hole whose profile matches the cross section of the revolution restricting section  112 B, the came plate  114  can be fitted to the sensor frame  112  that holds the image sensor  34  in a state where it is axially movable but cannot revolve relative to the sensor frame  112 .  
      The operation of focal point adjustment of the lens and the image sensor  34  is conducted before fitting the click mechanism to the hinge device because of the sequence of the steps of the assembling process. Additionally, as pointed out earlier, the click mechanism is arranged around the lens frame  110 , which is a hollow shaft, for the purpose of reducing the outer diameter of the hinge device. Thus, the profile of the hole of the cam plate  114  matches the external profile of the lens frame  110 . However, after the focal point adjustment operation, the revolution restricting section  110 B of the lens frame  110  and the revolution restricting section  112 B of the sensor frame  112  may not necessarily be located at the same position in the outer peripheral direction. In order for the cam plate  114  to be able to be fitted properly in such a situation, the gap separating the end facet  110 C of the lens frame  110  and the end facet  112 C of the sensor frame  112  is made to be greater than the height of the cam plate  114 . With this arrangement, it is possible to make the cam plate  114  allow the lens frame  110  to pass through it and rotate within the limit of the gap before it is fitted to the sensor frame  112 . In other words, it is possible to mount the cam plate  114  in position regardless of the positions of the frames after the focal point adjustment operation.  
      Although not shown, it will be understood easily that the electronic appliance of the sixth embodiment can be formed by using the hinge device of this embodiment.  
      As described above by way of preferred embodiments, a hinge device according to the present invention comprises a hollow shaft and a click mechanism arranged to the outside of the hollow shaft for the hinge device so that one or more than one functional members may be arranged in the hollow shaft. With this arrangement, if a camera unit is placed in the hollow shaft as a functional member, the camera unit and the click mechanism of the hinge device are not axially arranged side by side. In other words, the axial space of an appliance can be exploited effectively to raise the value of the appliance. Additionally, if the functional member is a camera unit, the hinge device of such an electronic appliance can highly effectively be utilized to contain a conversion lens, a high definition lens that is formed by combining a large number of lenses to show a large dimension in the direction of the optical axis thereof, a zoom lens and/or a lens having an AF function, although most of which are not illustrated in the drawings.  
      While the present invention is described above by way of preferred embodiments, the present invention is by no means limited to the above-described embodiments, which may be modified and altered without departing from the scope of the invention to find various applications.  
      For example, the functional member that is arranged in each of the above-described embodiments of hinge device is a camera unit or a lens, it is also possible to arrange some other functional member in the hinge device. Examples of such functional members include a microphone, an antenna, a speaker, a battery, a connector and so on. The functional member may be a member that operates as part or all of the function added to the electronic appliance. For example, the functional member may be an entire camera unit to be used for adding the function of a camera to the electronic appliance or a lens that is part of the camera unit.  
      Thus, the present invention can find applications in the field of electronic appliances including foldable portable telephone sets, note type personal computers, portable information terminals, digital cameras and so on that comprise two cabinets that are linked to each other by means of a hinge device in such a way that the two cabinets can be opened and closed relative to each other.  
      Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, and representative devices shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.