Abstract:
A personal digital assistant  1  composed of a main body  2  formed with an operation section  212;  a cover body  3  which is freely attached and slides parallel to the operating section  212  from a position overlapped on the operation section side of the main body  2;  and an energization spring  45  formed in the cover body  3  which applies force along a direction which maintains an opened state in an opened position where the cover body  3  has been made to slide from the main body  2.  Accordingly, a sliding type personal digital assistant can be stabilized in a closed position and/or an opened position and prevent opening or closing in a midway through position.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2004-299098, filed Oct. 13, 2004, the entire contents of which is incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a personal digital assistant, for example, a cellular phone, etc. with two housings (a main body and a cover body) formed with a practicable slide.  
         [0004]     2. Description of the Related Art  
         [0005]     As a conventional prior art cellular phone, there is what is called a foldable cellular phone in which a display section is formed in the cover body and a key input section formed in the main body. Both the cover body and the main body are attached so as to be foldable and overlapped with a hinge part. In addition, there is also a cellular phone which enables the cover body to slide on the main body. Guide grooves are formed in the lengthwise direction of the main body. Also, engagement tabs which freely engage during movement along the guide grooves are formed in the cover body. The cover body overlapped upon the main body and the guide grooves are made to engage with the engagement tabs. In such a cellular phone, the main body can be placed on a user&#39;s palm and the cover body slid against the main body by pressing the cover body with a person&#39;s thumb. In this manner, the operation section which is covered by the cover body can be exposed (for example, as disclosed in Japanese Laid-Open Patent Application No. 2003-110675 titled “MOBILE PHONE”).  
         [0006]     However, in the conventional prior art cellular phone having the above-mentioned sliding mechanism, because the slide stops midway through the closed position which overlaps the cover body upon the main body as well as the opened position in which the cover is made to slide completely away from the main body, there is the anxiety of not being able to switch functions. Thus, manipulation by the user to perform a sliding movement completely is complicated.  
       SUMMARY OF THE INVENTION  
       [0007]     The present invention of a personal digital assistant with a slide mechanism has been made in view of the above-mentioned conventional problem. Accordingly, the object of the present invention is to provide a personal digital assistant which can be stabilized in a closed position and/or an opened position and prevent opening or closing in a midway through position.  
         [0008]     In order to solve the above-mentioned problem, the present invention of a personal digital assistant (cellular phone  1 ) comprises a main body  2  formed with an operation section (ten-key pad  212 ); a cover body  3  which is freely attached and slides parallel to the operating section from a position overlapped on the operation section side of the main body  2 ; and an energization spring (torsion springs  45 ) formed in the cover body  3  which applies force to the direction which maintains an opened state in an opened position to which the cover body  3  has been made to slide from the main body  2 .  
         [0009]     According to the present invention, a sliding type personal digital assistant can be stabilized in a closed position and/or an opened position and prevent opening or closing in a midway through position.  
         [0010]     The above and further objects and novel features of the present invention will more fully appear from the following detailed description when the same is read in conjunction with the accompanying drawings. It is to be expressly understood, however, that the drawings are for the purpose of illustration only and are not intended as a definition of the limits of the invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]     FIGS.  1 A˜ 1 C are perspective diagrams showing a cellular phone as an embodiment of the present invention;  
         [0012]      FIG. 2  is an exploded perspective view diagram showing the main body for the cellular phone of  FIG. 1 ;  
         [0013]      FIG. 3  is a sectional side view diagram showing the cellular phone of  FIG. 1 ;  
         [0014]      FIG. 4  is an A-A cross-sectional view diagram of  FIG. 3 ;  
         [0015]      FIG. 5  is a B-B cross-sectional view diagram of  FIG. 3 ;  
         [0016]      FIG. 6  is an exploded perspective view diagram showing the cover body for the cellular phone of  FIG. 1 ;  
         [0017]      FIG. 7  is a back portion traverse sectional view diagram showing the cellular phone of  FIG. 1 ;  
         [0018]      FIG. 8  is a D-D cross-sectional view diagram of  FIG. 7 ;  
         [0019]      FIG. 9  is a cross-sectional view diagram showing the cellular phone of  FIG. 1 ;  
         [0020]      FIG. 10  is a cross-sectional view diagram for the cellular phone of  FIG. 1 ;  
         [0021]      FIG. 11  is an exploded perspective view diagram showing the mounting structure of the main body and cover body for the cellular phone;  
         [0022]      FIG. 12  is an exploded perspective view diagram showing the slide unit for attaching the main body and the cover body of  FIG. 11 ;  
         [0023]     FIGS.  13 A˜ 13 C are perspective diagrams showing the form of the slide unit corresponding to the form of the cellular phone of FIGS.  1 A˜ 1 C, respectively; and  
         [0024]      FIG. 14  is a sectional side view diagram showing the cellular phone of  FIG. 1 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0025]     Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the drawings.  
         [0026]     FIGS.  1 A˜ 1 C are perspective diagrams showing a cellular phone as an embodiment of the present invention.  
         [0027]     A cellular phone  1  comprises a main body  2  with a ten-key pad  212  formed in the upper surface and a cover body  3  with an LCD window  311  and cursor keys  351  formed in the upper surface. The main body  2  and the cover body  3  are attached so that the cover body  3  can be moved in backward and forward directions to the main body  2  with a slide unit  4  described later. Accordingly, the cellular phone  1  can be arranged in a state (closed position) with the cover body  3  overlapped upon the main body  2  concealing the ten-key pad  212  as seen in  FIG. 1A  or in a state (opened position) with the cover body  3  moved in a forward direction to the main body  2  revealing the ten-key pad  212  as seen in  FIG. 1C . Also,  FIG. 1B  shows an intermediate position of  FIGS. 1A and 1C .  
         [0028]      FIG. 2  is an exploded perspective view diagram showing the main body  2 .  
         [0029]     The external shape of the main body  2  is formed by a front case  21 , a rear case  22  and a battery cover  23  and, as shown in  FIG. 3 , a battery  24 , a main substrate  25 , etc. are encased in that inner portion.  
         [0030]      FIG. 3  is a sectional side view diagram showing the cellular phone  1 .  FIG. 4  is an A-A cross-sectional view diagram of  FIG. 3 .  FIG. 5  is a B-B cross-sectional view diagram of  FIG. 3 .  
         [0031]     In addition,  FIG. 3  corresponds to a C-C cross-section of  FIG. 4  and  FIG. 5 . The front portion and rear portion of the front case  21  and the rear case  22  are joined using screws  261  and  262  with a main substrate  25  situated in between as shown in  FIG. 4 .  
         [0032]     An FPC connector  251  (refer to  FIG. 2 ) is formed in the main substrate  25  and connected with a main substrate side connector  51  (refer to  FIG. 9 ) for an FPC substrate  5  (flexible printed circuit substrate) described later. In addition to this, a vibrator motor  252 , a main processor, a sensor for the ten-key pad  212 , a main antenna, a sub-antenna, a memory card slot  255 , a modem, a memory, a power source IC, an IF connector, an earphone connector, etc. are provided.  
         [0033]     The front case  21  is provided with the ten-key pad  212  and an FPC insertion opening  211  for passing through of the FPC substrate  5  described later. On the upper surface of the front case  21 , as seen in  FIG. 3  and  FIG. 5 , a base  41  for the slide unit  4  and guide rails  42  for the slide unit  4  are mounted with screw fasteners using screws  263 ,  264  described later. Also, a latching part  210  is provided in the rear portion of the FPC insertion opening  211  of the front case  21 . The rear end portion of the base  41 , as shown in  FIG. 9  and  FIG. 10  is fastened and situated between the front case  21  main body adjacent to the latching part  210 .  
         [0034]      FIG. 6  is an exploded perspective view diagram showing the cover body  3 . The cover body  3  external shape is formed with a front case  31 , a rear case  32 , a camera cover  33  and a rail cover  34 . Also, encased in that inner portion is a sub-substrate  35 , an LCD  36  (liquid crystal display), a camera unit  381 , a stereo speaker  382 , etc.  
         [0035]     The front case  31  is provided with an LCD window  311  and cursor key openings  312 . The LCD window  311  is transparent which permeates the display shown to the user by the LCD  36  as well as protects the LCD  36  built in the cover body  3 . The cursor key openings  312  expose the cursor keys  351  formed in the sub-substrate  35  which make keystroke operations possible by the user.  
         [0036]     The rear case  32 , as seen in  FIG. 11 , is provided with a connector through hole  321  for passing through a sub-substrate  35  side connector for the FPC substrate  5  described later.  
         [0037]      FIG. 7  is a sectional view diagram showing the cellular phone  1 .  FIG. 8  is a D-D cross-sectional view diagram of  FIG. 7 . In addition,  FIG. 7  corresponds to an E-E cross-section of  FIG. 8 . The front portion of the front case  31  and the rear case  32 , as shown in  FIG. 6  and  FIG. 8 , are joined by screws  391  with the sub-substrate  35  situated in between. Also, the rear portion of the front case  31  and the rear case  32  are joined by screws  392  with a frame  37  situated in between.  
         [0038]     In the lower surface of the rear case  32 , as seen in  FIGS. 7 and 8 , a rail  43  of the slide unit  4  is mounted with screw fasteners using screws  393 ,  394  and  395  described later. Also, the backside portion of the rail  43  mounted in the rear case  32  is formed with engagement holes  320  (refer to  FIG. 14 ) where engagement tabs  416 ,  424  described later project backward.  
         [0039]     The camera cover  33  is mounted on the front side of the rear case  32  and insulates the camera unit  381  and the stereo speaker  382  as shown in  FIG. 6 . The portion where the camera cover  33  of the cover body  3  is mounted constitutes the thickest portion  30  which has a more increased thickness than the other portions. Also, in the camera cover  33 , as shown in  FIGS. 6, 9  and  10 , a camera window  331  is provided which permits permeation of the light for an imaged object to reach the camera unit  381 .  
         [0040]     The rail cover  34  is mounted on the rear case  32  and, when the cellular phone  1  is in an opened position, the portion exposed to the front part of the main body  2  for the rail  43  is covered.  
         [0041]     The sub-substrate  35  is provided with a sub-processor, a camera power source IC, the cursor keys  351 , etc. The cursor keys  351  are exposed outward from the cursor key openings  312  which make keystroke operations possible by the user. Also, in the back surface of sub-substrate  35 , an FPC substrate connector  352  is connected to a sub-substrate side connector  52  for the FPC substrate  5  described later.  
         [0042]     The LCD  36  is supported by the frame  37 . The frame  37  is fixed to the rear case  32 . The camera unit  381  and the stereo speaker  382  are encased in the front portion of the front case  31  and the rear case  32  as shown in  FIG. 6 .  
         [0043]      FIG. 9  is a cross-sectional view diagram observed from the side of the cellular phone  1  of  FIG. 1A .  FIG. 10  is a cross-sectional view diagram observed from the side of the cellular phone  1  of  FIG. 1C . As seen in  FIGS. 9 and 10 , the main body  3  constitutes a shape which is thinner toward the front.  
         [0044]     The cover body  3  constitutes a shape which is thicker toward the front. Also, the front end part of the cover body  3  is the thickest portion  30  which has a more increased thickness. Within this thickness of the device, the camera unit  381 , the stereo speaker  382 , etc. are encased.  
         [0045]     The thickest portion  30 , as shown in  FIG. 9 , is situated ahead of the main body  2  even in a closed position and does not overlap over the main body  2 . Accordingly, even if a thick device is encased in the front end part, the thickness of the cellular phone  1  in a closed position does not increase.  
         [0046]     As shown in  FIG. 9 , in a closed position, both of the rear end surfaces of the main body  2  and the cover  3  are constructed with upward inclined surfaces toward the front. The cross-sectional shape of the rear end portion of the cover body  3  has an acute angle. Also, the cursor keys  351  of the cover body  3  are provided on an inclined surface of the rear end portion.  
         [0047]     Accordingly, as shown in  FIG. 10  in an opened position, when the rear end portion of the cover body  3  is advanced to the front portion of the ten-key pad  212  and the ten-key pad  212  is exposed, the rear end portion of the cover body  3  is situated at a cross-sectional acute angle ahead of the ten-key pad  212 . Since the upper surface of the main body  2  provides the ten-key pad  212  and the inclined surface of the rear end portion of the cover body  3  provides the cursor keys  351  consecutively, finger movement is simplified when manipulating the ten-key pad  212  and the cursor keys  351 .  
         [0048]     Additionally, as seen in  FIG. 10  in an opened position, since the thin front end portion of the main body  2  and the thin rear end portion of the cover body  3  overlap, the thickness of the cellular phone  1  in an opened position almost becomes the unified. Accordingly, there is no problem with the thickness doubling at the center portion crossing direction (back and forth directions) such as a conventional sliding type cellular phone and thus is user-friendly.  
         [0049]     The FPC substrate  5  comprises a main substrate side connector  51  and a sub-substrate side connector  52  on both ends which are connected to the main substrate  25  and the sub-substrate  35  described later. In a closed position, as shown in  FIG. 9 , the main substrate side connector  51  is situated forward and the sub-substrate side connector  52  is situated backward. From the closed position, when the cover body  3  is moved frontward, the sub-substrate side connector  52  will move forward. Thus, as shown in  FIG. 10  in the opened position, the sub-substrate side connector  52  will be situated forward more than the main substrate side connector  51 .  
         [0050]     Next, the slide unit  4  which is mounted to the main body  2  and the cover body  3  so that the cover body  3  can be moved in backward and forward directions to the main body  2  will be explained.  
         [0051]      FIG. 11  is an exploded perspective view diagram showing the mounting structure of the slide unit  4  which attaches between the main body  2  and the cover body  3 . As seen in  FIG. 12 , the outline configuration of the slide unit  4  is constituted by the base  41 , a pair of the guide rails  42 , the rail  43 , a pair of spacers  44  and a pair of torsion springs  45 .  
         [0052]     The base  41  and the guide rails  42  are mounted on the front case  21  of the main body  2  with screws  263 ,  264 . Also, the rail  43  is mounted on the rear case  32  of the cover body  3  with the screws  393 ,  394  and  395 .  
         [0053]      FIG. 12  is an exploded perspective view diagram of the slide unit  4 . The base  41  is composed of a base  411 , attachment parts  412  and guide rail stationary parts  413 . The base  411  and the guide rail stationary parts  413 , as shown in  FIG. 11 , are fixed to the front side part of the front case  21  for the main body  2 .  
         [0054]     The attachment parts  412  are formed on the protruding left and right side edges of the base  411  in the cover body  3  side. Also, an FPC insertion opening  414  is provided for pass through of the FPC substrate  5  in the base  411 .  
         [0055]     The attachment parts  412  are spaced up and down and adjoin the base  411  and the guide rail stationary parts  413 . The guide rail stationary parts  413  are joined to the left and right of the attachment parts  412 , respectively. The guide rails  42  are fastened to the guide rail stationary parts  413 .  
         [0056]     In between the base  411  and each of the guide rail stationary parts  413  for the rear part of the base  41 , the end parts of the base side arms  451  of the torsion springs  45  are mounted to be freely rotatable on the base side support shafts  415 , respectively. Also, the space between the base  411  and the guide rail stationary parts  413  constitutes the track for movement of the torsion springs  45 .  
         [0057]     Each of the guide rails  42  is composed of a base part  421 , an attachment part  422  and a spacer maintenance part  423 . The base parts  421  are fixed to the guide rail stationary parts  413  of the base  41 . The attachment parts  422  separate the spacer maintenance parts  423  from the guide rail stationary parts  413  and are connected to the base parts  421 . Both of the spacer maintenance parts  423  maintain free sliding on the rail  43  via the pair of spacers  44  arranged in between the guide rail stationary parts  413 , respectively.  
         [0058]     Also, in the rear end portion of the base  41  and each of the guide rails  42 , the engagement tabs  416 ,  424  are provided which project backward, respectively. As seen in  FIG. 14 , the engagement tabs  416 ,  424  engage with the engagement holes  320  formed in the rear case  32  and stop the cover body  3  which slides forward to the main body  2 . Even in the case where downward force is applied to the front side part of the cover body  3  in an opened position, the engagement tabs  416 ,  424  are engaged with the engagement holes  320  (refer to  FIG. 11 ). This prevents uplift of the cover body  3  back end from the main body  2 , thus the rigidity of the cellular phone  1  in an opened position can be enhanced.  
         [0059]     The rail  43  is composed of stationary parts  431 , attachment parts  432 , spacer stationary parts  433  and a coupling part  434 . A left and right pair of the stationary parts  431  are mounted in the rear case  32  in a parallel back and forth direction.  
         [0060]     The attachment parts  432  separate the spacer stationary parts  433  from the rear case  32  and connect with the stationary parts  431 . The spacer stationary parts  433  secure the left and right pair of spacers  44  in a parallel back and forth direction. Also, the protruding parts  436  which project upward are formed on the front end of the spacer stationary parts  433 . The protruding parts  436  contact with the front end of the guide rails  42 , respectively, and stop the rail  43  which slides backward to the guide rails  42  and the base  41 .  
         [0061]     The coupling part  434  connects the left and right pair of stationary parts  431 . The sub-substrate side connector  52  for the FPC substrate  5  is arranged on the upper surface of the coupling part  434 . On the lower surface of the front end left and right sides of the coupling part  434 , the end parts of the rail side arms  452  of the torsion springs  45  are mounted to be freely rotatable on the rail side support shafts  435 , respectively. The FPC substrate  5  pass through is situated between the section of the mounted left and right rail side support shafts  435 .  
         [0062]     The spacers  44  are a cross-section “]” type shape and cover the spacer stationary parts  433  of the rail  43 , respectively, and enable sliding of the base  41  and the guide rails  42  on the rail  43 . As for the material for the spacers  44 , it is preferable to use material with a low friction coefficient for the base  41  and the guide rails  42 .  
         [0063]     The torsion springs  45  are composed of a coiled portions  453  which join the base side arms  451  and the rail side arms  452 , as well as the base side arms  451  and the rail side arms  452 , respectively. The coiled portion  453  applies force so that the base side arms  451  and the rail side arms  452  can be expanded. The end part of the base side arms  451  are mounted to be freely rotatable on the base side support shafts  415  as well as the end part of the rail side arms  452  on the rail side support shafts  435 , respectively. Since the torsion springs  45  apply force so that the spacing of the end part of the base side arms  451  and the end part of the rail side arms  452  can be expanded, the accompanying force shifts in a direction so that the base side support shafts  415  and the rail side support shafts  435  become further apart, respectively.  
         [0064]     FIGS.  13 A˜ 13 C are perspective diagrams showing the form of the slide unit corresponding to the form of the cellular phone  1  of FIGS.  1 A˜ 1 C, respectively.  FIG. 13A  shows the closed position with the cover body  3  overlapped upon the main body  2 . The protruding parts  436  of the rail  43  front end are in contact with the front end of the guide rails  42 . At this stage, since the rail side support shafts  435  are situated backward more than the base side support shafts  415 , the elastic force of the torsion springs  45  is applied forcibly in a direction where the rail side support shafts  435  are further apart from the base side support shafts  415 , namely, backward.  
         [0065]     When the main body  2  of the cellular phone  1  in a closed position is placed in a user&#39;s palm and the cover body  3  is pressed forward with a person&#39;s thumb, the elastic force of the torsion springs  45  will be countered and the cover body  3  advances forward to an intermediate position as seen in  FIG. 13B . At this stage, since the rail side support shafts  435  and the base side support shafts  415  are located in a line on the left and right, the elastic force of the torsion springs  45  functions in the direction where the rail side support shafts  435  recede to the base side support shafts  415 , namely, an upright left and right direction to the rail  43 . Accordingly, the intermediate position is an unstable position in which the torsion springs  45  apply force in neither a backward nor a forward direction.  
         [0066]     When the cover body  3  is pressed forward with a person&#39;s thumb further from the intermediate position, since the rail side support shafts  435  are situated forward more than the base side support shafts  415 , the torsion springs  45  apply force in the direction where the rail side support shafts  435  are further apart from the base side support shafts  415 , namely, forward. Accordingly, when the cover body  3  is pressed forward more than the intermediate position and afterward even if the cover body  3  is not pressed, the cover body  3  moves ahead according to the elastic force of the torsion springs  45 .  
         [0067]     In the cover body  3 , as seen in  FIG. 14 , the engagement tabs  416 ,  424  formed in the rear end portion of the base  41  and the guide rails  42  engage with the engagement holes  320  formed in the rear case  32 . This stops the forward movement of the cover body  3  and the cellular phone  1  will be in the opened position. In cases where downward force is applied to the front portion of the cover body  3  in the opened position, the back end of the cover body  3  will attempt to uplift from the main body  2 . However, since the engagement tabs  416 ,  424  are engaged with the engagement holes  320 , the uplift of the cover body  3  from the base  41  and the guide rails  42  is prevented. Additionally, since the back end of the base interlocks with the latching part  210  of the front case  21  for the main body  2 , this prevents the base  41  from uplifting along with the cover body  3  and the rigidity of the cellular phone  1  in an opened position can be enhanced.  
         [0068]     Similarly, in cases where the cover body  3  is moved backward from an opened position to the intermediate position, although there is the necessary opposing force action of the elastic force in the torsion springs  45 , after the intermediate position the cover body  3  moves backward according to the elastic force of the torsion springs  45 .  
         [0069]     In addition, the movable radius of the coiled portions  453  centered on the base side support shafts  415 , namely, the added length of the base side arms  451  and the radius of the coiled portions  453  is shorter than the shortest separation (distance) of the rail side support shafts  435  and the base side support shafts  415 , respectively. Accordingly, the coiled portions  453  of the torsion springs  45  travel in a lateral track more than the rail side support shafts  435 . Although the track is constituted where the FPC substrate  5  travels between the rail side support shafts  435 , since the track of the torsion springs  45  is more lateral than the FPC substrate  5  track, the torsion springs  45  to not impede movement of the FPC substrate  5 .  
         [0070]     Similarly, the movable radius of the coiled portions  453  centered on the rail side support shafts  435 , namely, the added length of the rail side arms  452  and the radius of the coiled portions  453  is shorter than the shortest separation (distance) of the rail side support shafts  435  and the base side support shafts  415 , respectively. Accordingly, the coiled portions  453  of the torsion springs  45  travel on a more inner side track than the track of the base side support shafts  415 .  
         [0071]     As explained above in the preferred embodiment, the present invention can be multi-functionalized without increasing the thickness of the cellular phone  1 , because the thickest part which increases thickness in the main body  2  is formed in the front end portion of the cover body  3  and because a device having the thickness of the camera device  381 , the stereo speaker  382 , etc. can be encased in the thickest part.  
         [0072]     Additionally, since the thin front portion of the main body  2  and the thin rear portion of the cover body  3  overlap when moving the cover body  3  forward to the main body  2 , the thickness of the cellular phone  1  becomes unified in a back to front direction, which markedly enhances user-friendliness.  
         [0073]     Besides, although a sliding type cellular phone has been explained in the above-mentioned preferred embodiment, the present invention is not limited to this. For example, the present invention may be applied to other types of personal digital assistants, etc. Also, although the shape of the above-mentioned torsion springs  45  each contain one of the coiled portions  453 , these springs may use two coiled portions. Naturally, other constructional details may be suitably changed as well.  
         [0074]     While the present invention has been described with reference to the preferred embodiments, it is intended that the invention be not limited by any of the details of the description therein but includes all the embodiments which fall within the scope of the appended claims.