Abstract:
This invention relates to an electronic device or foldable cellular phone set in which boards arranged in two casings bendably connected to each other through a connecting portion are electrically connected to each other by a wireless communication unit using infrared rays or the like. As the wireless communication unit, either an optical method using infrared rays or the like, or a radio wave method using a radio wave can be used.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to an electronic device, e.g., a foldable cellular phone set, having a bendable portion and, more particularly, to an electronic device in which the electrical connection of the bendable connecting portion is improved.  
           [0003]    2. Description of the Prior Art  
           [0004]    As shown in FIG. 1, a foldable cellular phone set  60  is comprised of one side portion  62  having a display screen  61  and the like, and the other side portion  72  having input buttons  63  and the like. The two side portions  62  and  72  are bendably connected at substantially their central position by a connecting portion  80 , so they can be opened/closed. As shown in FIG. 2, one side portion  62  of the foldable cellular phone set  60  is comprised of a first front casing  64  and first back lid  66  that can be divided in the front and back directions. The other side portion  72  is similarly formed of a second front casing  74  and second back lid  76 . The connecting portion  80  has a connecting member  80   a  on the first front casing  64  side and a connecting member  80   b  on the second front casing  74  side. The connecting members  80   a  and  80   b  are built in the connecting portion  80  together with other connecting members, so the connecting portion  80  is pivotal.  
           [0005]    As shown in FIG. 3, one side portion  62  of the foldable cellular phone set has a first board  52 , to which a liquid crystal panel for the display screen  61  and a receiver for producing the voice of the other party are to be connected, such that the board  52  is stored between the first front casing  64  and first back lid  66 . The other side portion  72  has a second board  54 , to which contact components of the input buttons  63  for inputting telephone numbers and the like and a microphone are to be connected, such that the board  54  is stored between the second front casing  74  and second back lid  76 .  
           [0006]    As shown in FIG. 3, the first and second boards  52  and  54  are electrically connected through a flexible FPC (Flexible Printed Circuit board)  50 . The FPC  50  is connected at its one end to the first board  52  through a connector  56 , and at its other end to the second board  54  through a connector  58 . The FPC  50  is twisted by one turn to form one helical loop at its substantial center in the longitudinal direction, and is connected to the first and second boards  52  and  54 . The first and second boards  52  and  54  are fixed to the first and second front casings  64  and  74 , respectively, and the first and second back lids  66  and  76  are attached to the first and second front casings  64  and  74 , respectively so the first and second boards  52  and  54  are stored. In this manner, since the FPC  50  is stored in the connecting portion  80  as it is twisted by one turn, one and the other side portions  62  and  74  respectively storing the first and second boards  52  and  54  can folded while maintaining electrical connection to each other.  
           [0007]    In another prior art disclosed in Japanese Unexamined Patent Publication No. 11-308173, photocouplers are formed on those portions of two casings through which the casings are foldably connected to each other. The casings are electrically connected to each other through the photocouplers.  
           [0008]    In the conventional foldable cellular phone set, the FPC connectors  56  and  58  are mounted on the respective boards. The two ends of the FPC  50  are fitted in the connectors  56  and  58 , so the first and second boards  52  and  54  are electrically connected to each other. Hence, the manufacturing line requires the operation of building the FPC  50  to the connectors  56  and  58  and the like, which is cumbersome. Since the ends of the FPC  50  are thin, when they are to be fitted in the connectors, the connector  56  may be damaged, or the FPC  50  may undesirably bend. Furthermore, if the FPC  50  and connector  56  and the like are not sufficiently fitted with each other, they cause defective electrical connection, resulting in a defective product.  
           [0009]    The FPC  50  is twisted into a loop in the connecting portion  80 , and is usually in substantially tight contact with the inner surface of the connecting portion  80 . When water enters through the connecting portion  80 , capillarity occurs between the FPC  50  and the inner surface of the connecting portion  80 , and the water may flow deeply into the connecting portion  80  to wet the first board  52  and the like. This causes corrosion of the first board  52  and the like to lead to a trouble or the like. As the FPC  50  runs from the inside to the outside of the connecting portion  80 , the connecting portion  80  cannot be sealed completely.  
           [0010]    As the functions of the cellular phone set increase, the amount of information transmitted between the first and second boards  52  and  54  increases. To transmit the information, it is required to increase the number of signal lines in the FPC  50 . The space in the connecting portion  80  through which the FPC  50  can run is limited. If the width of the FPC  50  is increased in an attempt to increase the number of signal lines, the FPC  50  cannot run through the connecting portion  80 . In addition, in recent years, demands for downsizing of the cellular phone set increase. To increase the width of the connecting portion  80  for the FPC  50  leads to an increase in size of the phone set main body, failing to downsizing. Information transmission using the FPC  50  is reaching its limit.  
           [0011]    According to the invention disclosed in Japanese Unexamined Patent Publication No. 11-308173, the casings are electrically connected to each other through the photocouplers respectively provided to the two casings. The two photocouplers abut against each other when the respective casings are opened completely. During opening/closing operation, communication between the two photocouplers is disconnected.  
         SUMMARY OF THE INVENTION  
         [0012]    The present invention has been made to solve the above inconveniences of the prior art, and has as its object to provide an electronic device or foldable cellular phone formed by foldably connecting two casings, which can be assembled easily, perform communication reliably, cope with a large communication amount, and always make electrical connection regardless of the folded state of the casings, so downsizing and cost reduction can be realized.  
           [0013]    In order to achieve the above object, according to the present invention, there is provided an electronic device or foldable cellular phone set, in which boards arranged in two casings foldably connected to each other through a connecting portion are electrically connected to each other by a wireless communication means using infrared rays or the like. More specifically, transmission/reception modules for infrared communication (IrDA) are arranged in the connecting portion coaxially with the rotation axis of the connecting portion, such that they oppose each other. Even when the connecting portion of the foldable cellular phone set is bent, the transmission/reception surfaces of the transmission/reception modules can always oppose each other, and communication between them is not disconnected by folding operation.  
           [0014]    As the wireless communication means, ultraviolet rays, visible light, and a radio wave with a weak output can be used in addition to the infrared rays. When the transmitting/receiving portions use light, their transmitting/receiving surfaces must oppose each other. When the transmitting/receiving portions use a radio wave, their transmitting/receiving surfaces need not oppose each other, and transmission/reception antennas may be appropriately arranged on the two casings respectively. When the pivot angle of the connecting portion is not large, the boards may be connected by using optical fibers.  
           [0015]    The transmission/reception modules can be arranged at that portion of the connecting portion having the conventional structure where the FPC used to run. When the FPC is used, it is twisted and arranged, so a substantially cylindrical space is formed in advance. When the transmission/reception modules are arranged at the portion where the FPC used to run, a connecting method which uses infrared modules and the like can be easily applied to the structure of the conventional foldable cellular phone set in which the transmission/reception modules are connected by using the FPC, without largely changing the shape of the basic constituent components such as casings.  
           [0016]    As is apparent from the above aspects, with the electronic device or foldable cellular phone set that can be obtained by the present invention, the cumbersome operation of connecting the FPC can be omitted, so the assembly cost can be reduced. In particular, as the IrDA modules can be mounted on the boards by an automatic mounter or the like, they do not need manual assembly unlike in the case using the FPC, so the assembly cost can be reduced largely.  
           [0017]    Damage to the FPC connector which occurs when connecting the FPC to the FPC connector can be prevented. Also, disconnection in the FPC, which is due to the bending of the FPC, can be prevented.  
           [0018]    Water can be prevented from entering the foldable cellular phone set through the connecting portion. Even if water should enter the phone set, it does not come in contact with any board.  
           [0019]    Even if the amount of information exchanged between the connected boards increases, this increase in the amount of information can be easily coped with without adding or enlarging the interconnections structurally, unlike in the case of connection using wires.  
           [0020]    The above and many other objects, features and advantages of the present invention will become manifest to those skilled in the art upon making reference to the following detailed description and accompanying drawings in which preferred embodiments incorporating the principle of the present invention are shown by way of illustrative examples. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]    [0021]FIG. 1 is a perspective view showing the outer appearance of a conventional foldable cellular phone set;  
         [0022]    [0022]FIG. 2 is an exploded side view showing components of the conventional foldable cellular phone set;  
         [0023]    [0023]FIG. 3 is a plan view showing the boards of the conventional foldable cellular phone set;  
         [0024]    [0024]FIG. 4 is a perspective view showing the outer appearance of a foldable cellular phone set of the present invention;  
         [0025]    [0025]FIG. 5 is a side view showing the foldable cellular phone set of the present invention in the open state;  
         [0026]    [0026]FIG. 6 is a side view showing the foldable cellular phone set of the present invention in the folded state;  
         [0027]    [0027]FIG. 7 is an exploded side view showing components of the foldable cellular phone set of the present invention;  
         [0028]    [0028]FIG. 8 is a rear perspective view showing the two front casings of the foldable cellular phone set of the present invention;  
         [0029]    [0029]FIG. 9 is a plan view showing how the boards are attached in the foldable cellular phone set of the present invention;  
         [0030]    [0030]FIG. 10 is a perspective view showing the two boards of the foldable cellular phone set of the present invention;  
         [0031]    [0031]FIG. 11 is a plan view showing the two boards of the foldable cellular phone set of the present invention;  
         [0032]    [0032]FIG. 12 is a partial sectional view showing the connecting portion of the foldable cellular phone set of the present invention;  
         [0033]    [0033]FIG. 13 is a partial plan view showing the connecting portion of the foldable cellular phone set of the present invention;  
         [0034]    [0034]FIG. 14 is a partial plan view showing another example of the foldable cellular phone set of the present invention; and  
         [0035]    [0035]FIG. 15 is a partial plan view showing still another example of the foldable cellular phone set of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0036]    Several preferred embodiments of the present invention will be described with reference to the accompanying drawings by way of a foldable cellular phone set.  
         [0037]    [0037]FIG. 4 shows a foldable cellular phone set  2  of the present invention entirely. Similarly to the conventional foldable cellular phone set  60 , the foldable cellular phone set  2  is comprised of one side portion  12  having a display screen  10  and the like, and the other side portion  22  having input buttons  20  and the like. As shown in FIGS. 5 and 6, one and the other side portions  12  and  22  are foldably connected to each other at substantially their center by a connecting portion  8 . FIG. 5 shows an open state, and FIG. 6 shows a folded state.  
         [0038]    As shown in FIG. 7, one side portion  12  is formed of a first front casing  14  and first back lid  16  to be respectively fitted in its front and back sides, and a first board  4  to be inserted between the first front casing  14  and the first back lid  16 . A connecting member  8   a  to serve as part of the connecting portion  8  is formed on the first front casing  14  on the connecting portion  8  side.  
         [0039]    As shown in FIG. 7, the other side portion  22  is formed of a second front casing  24  and second back lid  26  to be respectively fitted in its front and back sides, and a board  6  to be inserted between the second front casing  24  and the second back lid  26 . A connecting member  8   b  to serve as part of the connecting portion  8  is formed on the second front casing  24  on the connecting portion  8  side.  
         [0040]    As shown in FIG. 8, the connecting portion  8  is substantially cylindrical as a whole, and has stoppers  17  at its two ends for pivotally stopping the respective connecting members of one and the other side portions  12  and  22 . A cylindrical space is formed in the center of the connecting portion  8 .  
         [0041]    A liquid crystal panel for the display and a receiver for producing the voice of the other party are mounted on the first board  4 . The contact components of the buttons for inputting telephone numbers and the like, a microphone, and the like are mounted on the board  6 . FIG. 9 shows a state wherein the first and second boards  4  and  6  are respectively fixed to the first and second front casings  14  and  24 .  
         [0042]    As shown in FIGS.  9  to  11 , infrared modules  5  and  7  are attached to the first and second boards  4  and  6  on the connecting portion  8  sides. In FIG. 10, a line denoted by a reference character X shows a rotation axis of the connecting portion  8 . The infrared module  5  having an infrared-ray-receiving/emitting element (not shown) in it converts a signal from the first board  4  into infrared rays and emits an infrared signal. Upon reception of an infrared signal, the infrared module  5  converts it into an electrical signal and sends it to the first board  4 . The infrared module  7  has the same arrangement as that of the infrared module  5 . The infrared modules  5  and  7  oppose each other with their light-receiving/emitting surfaces, as shown in FIG. 13, and are attached to the first and second boards  4  and  6 , respectively, such that their two center axes coincide with the rotation axis X of the connecting portion  8 , as shown in FIG. 12, when the first and second boards  4  and  6  are respectively fixed to the first and second front casings  14  and  24 .  
         [0043]    In this manner, in the foldable cellular phone set  2  of the present invention, since the center axes of the infrared modules  5  and  7  are arranged coaxially with the rotation axis X of the connecting portion  8 , the positional relationship between the infrared modules  5  and  7  relative to each other does not change at all whether in the open state or the folded state, as shown in FIGS.  5  and  6 , and the infrared modules  5  and  7  are constantly held to oppose each other.  
         [0044]    Therefore, no matter how the connecting portion  8  of the foldable cellular phone set  2  is bent (rotated) during communication using the infrared modules  5  and  7 , communication can be maintained. The foldable cellular phone set  2  can operate not only in the open state but also in any state.  
         [0045]    Other than the above embodiment, the infrared modules  5  and  7  may come into tight contact with the inner surface of the connecting portion  8 , or the gap between the first or second board  4  or  6  extending from one or the other side portion  12  or  22 , respectively, and one or the other side portion  12  or  22  may be waterproofed. This can prevent water or the like from entering one and the other side portions  12  and  22  through the connecting portion  8 . At this time, the transmitting/receiving surfaces of the infrared modules  5  and  7  may expose from the foldable cellular phone set  2  or may be inside the connecting portion  8 .  
         [0046]    The infrared modules  5  and  7  need not be formed in the connecting portion  8 , but may be formed at appropriate portions of the main bodies of the first boards  4  and  6  arranged in one and the other side portions  12  and  22 , respectively, and may be connected to each other through optical fibers  9  and  11 , as shown in FIG. 14. In this case, one end of the optical fiber  9  is attached to the light-receiving/emitting surface of the infrared module  5 . The other end of the optical fiber  9  runs into the connecting portion  8  and is arranged coaxially with the rotation axis of the connecting portion  8 . One end of the optical fiber  11  is attached to the light-receiving/emitting surface of the infrared module  7 . The other end of the optical fiber  11  runs into the connecting portion  8  and is arranged coaxially with the rotation center of the connecting portion  8 , so it opposes the end face of the optical fiber  9 .  
         [0047]    With this arrangement, infrared communication is performed through the optical fibers  9  and  11 . The other end face of the optical fiber  9  and that of the optical fiber  11  constantly oppose each other regardless of whether the foldable cellular phone set  2  is folded or not. Hence, communication is not disconnected.  
         [0048]    Furthermore, according to the present invention, one and the other side portions  12  and  22  may be connected to each other by a radio wave method, in place of the infrared modules  5  and  7 . In this case, the first and second boards  4  and  6  have a wireless transmitting/receiving function (not shown) with a predetermined frequency and output. As shown in FIG. 15, antennas  13  and  15  are formed in the connecting portion  8  or at those positions of one and the other side portions  12  and  22  where a radio wave can be transmitted or received. Hence, one and the other side portions  12  and  22  can transmit and receive signals to and from each other through the antennas  13  and  15  regardless of whether the foldable cellular phone set  2  is folded. Also, since the antennas can be formed even when the connecting portion  8  is sealed, entering of water or the like can be prevented reliably.