Abstract:
A foldable electronic device includes a first body having a display and a screen for protecting the display, and a second body having a plurality of operation keys. The first and second are rotatable to each other through a hinge. The first and second bodies have first and second surfaces facing each other when the electronic device is folded. The operation keys project by a height from the second surface, and the first body is formed a recess at the first surface, the recess having a depth equal to or greater than the height. The second body has a projection projecting from the second surface. The first body has an elastic piece through which the screen is mounted on the first body such that the screen moves in the recess in a depth-wise direction of the recess. The projection pushes the screen when the electronic device is folded, thereby the elastic piece being compressed, and the elastic piece pushes the screen back when the electronic device is unfolded.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates to a foldable handy electronic device including an upper body and a lower body both of which are designed rotatable to each other such that the electronic device is folded and unfolded, and one of which has a display and the other has an interface through which a user can operate the electronic device. 
   2. Description of the Related Art 
   As an example of a foldable handy electronic device, a cellular phone is well known. 
   A foldable cellular phone is comprised generally of an upper body having a display and a speaker, and a lower body having operation keys and a microphone. After dialing, a user puts his/her ears onto a speaker of the upper body, and speaks to a microphone of the lower body. 
     FIG. 1  is a cross-sectional view of a conventional cellular phone. 
   The illustrated conventional cellular phone is comprised of a first body  1  corresponding to the above-mentioned upper body, a second body  2  corresponding to the above-mentioned lower body, and a hinge  105  connecting the first and second bodies  1  and  2  rotatably to each other. The first body  1  has a first surface facing the second body  2  when the cellular phone is folded, and the second body  2  has a second surface facing the first body  1  when the cellular phone is folded. The first body  1  includes a display  3  at the first surface, and a screen  5  arranged above the display  3  for protecting the display  3 . The second body  2  includes an interface  6  at the second surface. The interface  6  includes a plurality of operation keys  7  arranged on the second surface. 
   The first body  1  includes a front case  101  facing the second body  2  when the cellular phone is folded, and a rear case  102 . Similarly, the second body  2  includes a front case  103  facing the first body  1  when the cellular phone is folded, and a rear case  104 . 
   By rotating the first body  1  by about 180 degrees relative to the second body  2 , the display  3  and the interface  6  are exposed to a user such that the user can look at the display  3  and operate the cellular phone through the interface  6 . By rotating the first body  1  relative to the second body  2  so that the cellular phone is folded as illustrated in  FIG. 1 , the display  3  and the interface  6  are hidden, and hence, they are protected from being damaged, even if a user drops the cellular phone. 
     FIG. 2  is an enlarged view of an encircled portion A of the cellular phone. 
   As illustrated in  FIG. 2 , the operation keys  7  and the screen  5  are kept spaced away from each other by a clearance S 1  such that they do not interfere with each other when the cellular phone is folded. 
   In the conventional cellular phone illustrated in  FIG. 2 , the display  3  and the interface  6  face each other when the cellular phone is folded. If the clearance S is not sufficient, the operation keys  7  of the interface  6  would interfere with the display  3  when the hinge  105  is worn out in long use, resulting in that the display  3  is damages at a surface thereof. 
   If the operation keys  7  are designed to be small in height, it would be possible to keep the clearance S sufficient between the display  3  and the operation keys  7 . However, a user might fail to sufficiently compress the operation keys  7 , resulting in that a user could not correctly operate the cellular phone. 
   Japanese Patent Application Publication No. 2001-308992 has suggested a cellular phone including a first body, a second body, and a hinge through which the first and second bodies are rotatably connected to each other. The second body includes a main display. An auxiliary display is arranged in the hinge. The auxiliary display is always exposed regardless of whether the cellular phone is folded or unfolded. 
   Japanese Patent Application Publication No. 2001-274880 has suggested a cellular phone including a first body, a second body, and a hinge through which the first and second bodies are rotatably connected to each other. The second body includes a main display. An auxiliary display is arranged in the hinge. The auxiliary display is always exposed regardless of whether the cellular phone is folded or unfolded. Received data is displayed in the auxiliary display, being scrolled every predetermined period of time. 
   Japanese Patent Application Publication No. 2001-186226 has suggested a cellular phone including a first body, a second body, and a hinge through which the first and second bodies are rotatably connected to each other. The first body is designed to have a first liquid crystal display device at a front thereof, and a second liquid crystal display device at a rear thereof. 
   Japanese Patent Application Publication No. 10-336065 has suggested a cellular phone including a first body, a second body, and a hinge through which the first and second bodies are rotatably connected to each other. The first body includes a speaker, and the second body includes a microphone, operation keys, a substrate on which radio-signal circuits are mounted, and a display. 
   Japanese Patent Application Publication No. 8-33027 has suggested a cellular phone including a first body, a second body, and a hinge through which the first and second bodies are rotatably connected to each other. The cellular phone is designed to be unfolded in one action of a user. 
   Japanese Patent Application Publication No. 8-9004 has suggested a cellular phone including a first body, a second body, and a hinge through which the first and second bodies are rotatably connected to each other. The cellular phone is designed to be unfolded, to extend an antenna, and to be put into an off-hook condition in one action of a user. 
   Japanese Patent Application Publication No. 7-131850 has suggested a cellular phone including a first body, a second body, and a hinge through which the first and second bodies are rotatably connected to each other. The cellular phone is designed to be unfolded by one hand of a user. 
   SUMMARY OF THE INVENTION 
   In view of the above-mentioned problems in the conventional handy electronic devices such as a cellular phone, it is an object of the present invention to provide an electronic device in which a display and an interface are kept sufficiently spaced away from each other to avoid them to interfere with each other, and which enables a user to sufficiently compress operation keys such that a user could correctly operate an electronic device. 
   In one aspect of the present invention, there is provided a foldable electronic device including a first body having a display and a second body having an interface through which a user can operate the electronic device, the first and second bodies being rotatable to each other through a hinge, the first body having a first surface facing the second body when the electronic device is folded, the second body having a second surface facing the first body when the electronic device is folded, the interface projecting by a height from the second surface, the first body being formed a recess with the first surface, the recess aligning with the interface when the electronic device is folded, and having a depth equal to or greater than the height, and the display being located within the recess. 
   There is further provided a foldable electronic device including a first body having a display and a screen for protecting the display, and a second body having an interface through which a user can operate the electronic device, the interface including a plurality of operation keys, the first and second bodies being rotatable to each other through a hinge, the first body having a first surface facing the second body when the electronic device is folded, the second body having a second surface facing the first body when the electronic device is folded, the operation keys projecting by a height from the second surface, the first body being formed a recess at the first surface, the recess aligning with the operation keys when the electronic device is folded, and having a depth equal to or greater than the height, the second body having at least one projection projecting from the second surface, the first body having an elastic piece through which the screen is mounted on the first body such that the screen moves in the recess in a depth-wise direction of the recess, the projection pushing the screen in the depth-wise direction when the electronic device is folded, thereby the elastic piece being compressed, and the elastic piece pushing the screen back when the electronic device is unfolded. 
   For instance, the elastic piece may be sandwiched between the screen and the display. As an alternative, the elastic piece may be sandwiched between the screen and the first body. 
   For instance, the screen and the display may be fixed to each other. 
   It is preferable that the first body is formed with a hole into which the projection is inserted when the electronic device is folded, the projection pushing the screen through the hole when the electronic device is folded. 
   It is preferable that the second body has two projections projecting from the second surface such that the projections push the screen at opposite sides of the screen. 
   It is preferable that the screen has a thicker portion than the rest thereof, the projection pushing the screen at the thicker portion. 
   It is preferable that the elastic piece is located around the recess. 
   It is preferable that the elastic piece is fixedly adhered to the screen. 
   For instance, the foldable electronic device is a cellular phone. 
   The advantages obtained by the aforementioned present invention will be described hereinbelow. 
   In the foldable electronic device in accordance with the present invention, it is possible to prevent a display and an interface from interfering with each other when the electronic device is folded, ensuring that the display is not damaged. 
   In addition, since operation keys of an interface can be designed sufficiently tall, a user can operate the electronic device without failure. 
   Furthermore, since a screen moves in a depth-wise direction of a recess as the electronic device is folded or unfolded, it is possible to prevent a display and an interface from interfering with each other, and operation keys of an interface can be designed sufficiently tall. 
   The above and other objects and advantageous features of the present invention will be made apparent from the following description made with reference to the accompanying drawings, in which like reference characters designate the same or similar parts throughout the drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a cross-sectional view of a conventional cellular phone. 
       FIG. 2  is an enlarged view of an encircled portion A in  FIG. 1 . 
       FIG. 3  is a front view of a cellular phone in accordance with the first embodiment of the present invention. 
       FIG. 4  is a cross-sectional view taken along the line IV-IV in  FIG. 3 , showing that the cellular phone illustrated in  FIG. 3  is folded. 
       FIG. 5  is an enlarged view of an encircled portion B in  FIG. 4 . 
       FIG. 6  is a front view of a cellular phone in accordance with the second embodiment of the present invention. 
       FIG. 7A  is a cross-sectional view taken along the line VII-VII in  FIG. 6 , showing that the cellular phone illustrated in  FIG. 6  is almost folded. 
       FIG. 7B  is a cross-sectional view taken along the line VII-VII in  FIG. 6 , showing that the cellular phone illustrated in  FIG. 6  is completely folded. 
       FIG. 8A  is an enlarged view of an encircled portion C in  FIG. 7B . 
       FIG. 8B  is an enlarged view of an encircled portion C in  FIG. 7B . 
       FIG. 9  is a partial cross-sectional view of a cellular phone in accordance with the third embodiment of the present invention. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Preferred embodiments in accordance with the present invention will be explained hereinbelow with reference to drawings. 
   In the embodiments mentioned below, the foldable electronic device in accordance with the present invention is applied to a cellular phone. However, it should be noted that the foldable electronic device in accordance with the present invention may be applied to other handy communication-making terminals such as a personal digital assistant (PDA). 
   First Embodiment 
     FIGS. 3 to 5  illustrate a cellular phone in accordance with the first embodiment of the present invention.  FIG. 3  is a front view of the cellular phone in accordance with the first embodiment,  FIG. 4  is a cross-sectional view taken along the line IV-IV in  FIG. 3 , showing that the cellular phone is folded, and  FIG. 5  is an enlarged view of the encircled portion B in  FIG. 4 . 
   With reference to  FIG. 3 , the cellular phone is comprised of a first body  1  and a second body  2 . The first and second bodies  1  and  2  are rotatably connected to each other through a hinge  105 . The hinge  105  may be a separate part from the first and second bodies  1  and  2 , or a part of the first and second bodies  1  and  2  may define the hinge  105 . 
   As best illustrated in  FIG. 4 , the first body  1  is comprised of a front case  101  facing the second body  2  when the cellular phone is folded, and a rear case  102  exposed outside even when the cellular phone is folded. Similarly, the second body  2  is comprised of a front case  103  facing the first body  1  when the cellular phone is folded, and a rear case  104  exposed outside even when the cellular phone is folded. 
   As illustrated in  FIG. 3 , the first body  1  includes a display  3 , a screen  5  (see  FIG. 4 ) mounted above the display  3  for protecting the display  3 , a pair of cushions  10 , and a speaker  22 . 
   For instance, the display  3  is comprised of a thin liquid crystal display (LCD) device or a thin organic electroluminescence (EL) display for displaying communication data and/or characters. 
   The second body  2  includes an interface  6  through which a user operates the cellular phone, a pair of projections  11  which make contact with the cushions  10  when the cellular phone is folded, and a microphone  23 . As best illustrated in  FIG. 4 , the interface  6  is comprised of a plurality of operation keys  7  arranged a surface of the front case  103  of the second body  2 , a rubber sheet  8  on which the operation keys  7  are mounted, and a dome sheet  9  having a plurality of dome-shaped buttons arranged just below the operation keys  7  through the rubber sheet  8 . 
   As illustrated in  FIG. 4 , the front case  101  of the first body  1  is formed with an opening through which the display  3  is exposed. In addition, the first body  1  is formed with a recess  4  around the opening. In other words, the opening through which the display  3  is exposed is located at the bottom of the recess  4 . The screen  5  is fixed at the bottom of the recess  4  such that the screen  5  is located slightly above and in alignment with the display  3 . 
   After the display  3  is fixedly fit into the recess  4  formed at the front case  101 , the screen  5  is fixed to the recess  4 . The display  3  may be fixed to the recess  4  by means of screws at a bottom of the recess  4 , or by adhering the display  3  onto a bottom of the recess  4 . 
   The recess  4  has an area sufficient for covering the operation keys  7  when the cellular phone is folded. In addition, the recess  4  has a depth sufficient for ensuring a clearance between a surface of the screen  5  and tops of the operation keys  7 . 
   The screen  5  protects the display  3  from being damaged and/or contaminated. The screen  5  has such transparency that a user can observe what is displayed in the display  3 . To this end, it is preferable that the screen  5  is larger in size than the display  3 . 
   However, the cellular phone may be designed not to include the screen  5 , because the cellular phone is folded during not used, and hence, the display  3  is scarcely damaged, and further because the display  3  is always kept away from the interface  6  in the cellular phone in accordance with the first embodiment. 
   As mentioned earlier, the second body  2  is comprised of the front case  103  and the rear case  104 . 
   The front case  103  is formed with one or more openings through which a user operate the operations keys  7 . If the interface  6  is entirely exposed, the front case  103  is designed to have an opening through which the interface  6  is exposed. If the operation keys  7  are individually exposed, the front case  103  is designed to have openings in the same number as the number of the operation keys  7 . 
   As mentioned above, the interface  6  is comprised of the operation keys  7 , the rubber sheet  8 , and the dome sheet  9 . If a certain operation key  7  is pushed down, a dome-shaped button associated with the operation key  7  is pushed down, and thus, a signal is transmitted to an internal circuit (not illustrated) from the dome-shaped button. The interface  6  is fixed to the front case  103  at the rear of the interface  6  such that a user can operate the operation keys  7  at a front of the front case  103 . 
   By rotating the first and second bodies  1  and  2  from a state where the cellular phone is unfolded as illustrated in  FIG. 3 , the cellular phone is folded, as illustrated in  FIG. 4 . The front case  101  of the first body  1  is formed with two recesses outside the recess  4 , and the cushions  10  composed of elastic material are kept compressed into the recesses. The front case  103  of the second body  2  is formed with two projections  11  in alignment with the cushions  10 . When the cellular phone is folded, the projections  11  make contact with the cushions  10 , so that the front cases  101  and  103  are prevented from being damaged due to interference with each other. 
     FIG. 5  is an enlarged view of the encircled portion B in  FIG. 4 . 
   As illustrated in  FIG. 5 , the recess  4  is formed at the bottom thereof with a mold  101   a  onto which the display  3  is to be fixed. 
   A depth of the recess  4  is dependent on a projecting length of the operation keys  7 . Now assuming that a clearance made between the front case  101  of the first body  1  and the front case  103  of the second body  2  when the cellular phone is folded is expressed as “D 1 ”, a clearance made between the operation keys  7  and the screen  5  when the cellular phone is folded is expressed as “D 2 ”, a clearance made between a surface of the front case  101 , closer to the second body  2 , and the screen  5  is expressed as “D 3 ”, and a clearance made between the front case  103  of the second body  2  and the tops of the operation keys  7  is expressed as “D 4 ”, the following relation is established.
 
 D 1 +D 3 =D 2 +D 4
 
   The clearance D 1  becomes smaller as the cushions  10  are degraded because of long use. Even if the clearance D 1  becomes zero, that is, the front case of the first body  1  makes direct contact with the front case  103  of the second body  2 , it would be necessary to prevent the display  3  from being damaged due to direct contact between the operation keys  7  and the screen  5 . 
   If the clearance D 2  is designed greater than the clearance D 1  (D 2 &gt;D 1 ), the clearance D 3  would be greater than the clearance D 4  (D 3 &gt;D 4 ), preventing the display  3  from being damaged at a surface thereof. 
   As mentioned above, the front case  101  of the first body  1  is formed with the recess  4  aligning with the interface when the electronic device is folded, and having a depth sufficient for absorbing a height of the operation keys  7 . The display  3  is arranged in the recess  4 . Accordingly, the display  3  and the interface  6  are kept sufficiently spaced away from each other to avoid them to interfere with each other, and a user can sufficiently compress the operation keys  7  to correctly operate the cellular phone. 
   Second Embodiment 
     FIGS. 6 ,  7 A,  7 B,  8 A and  8 B illustrate a cellular phone in accordance with the second embodiment of the present invention. 
     FIG. 6  is a front view of the cellular phone in accordance with the second embodiment,  FIG. 7A  is a cross-sectional view taken along the line VII-VII in  FIG. 6 , showing that the cellular phone is almost folded,  FIG. 7B  is a cross-sectional view taken along the line VII-VII in  FIG. 6 , showing that the cellular phone is completely folded, and  FIGS. 8A and 8B  are enlarged views of an encircled portion C in  FIG. 7B . 
   The cellular phone in accordance with the second embodiment is structurally different from the cellular phone in accordance with the first embodiment in that, as best illustrated in  FIG. 6 , the second body  2  in the second embodiment is formed with two elongate projections  12 , and the first body  1  in the second embodiment is formed with two elongate holes  13  into which the projections  12  are fit when the cellular phone is folded, and further that a packing  14  is sandwiched between the display  3  and the screen  5 , as illustrated in  FIGS. 8A and 8B . 
   The projections  12  extend in parallel with and in the vicinity of shorter edges of the second body  2 , and the elongate holes  13  are arranged around the display  3  in the vicinity of shorter edges of the first body  1 . 
   The cellular phone in accordance with the second embodiment has the same structure as the cellular phone in accordance with the first embodiment except the above-mentioned projections  12 , holes  13  and packing  14 . Parts or elements that correspond to the first embodiment have been provided with the same reference numerals, and operate in the same manner as corresponding parts or elements in the first embodiment, unless explicitly explained hereinbelow. 
   As illustrated in  FIGS. 8A and 8B , the screen  5  is designed to have a size to extend beyond the holes  13 . 
   The screen  5  in the second embodiment is designed to have stiffness to some degree unlike the screen  5  in the first embodiment. This is because the screen  5  has to transfer a stress given from the projections  12  when the cellular phone is folded, to the packing  14 , as mentioned later in detail, and further because if the screen  5  is deformed due to repeated application of stress to the screen  5 , a user would have difficulty in reading what is displayed in the display  3 . 
   Hence, the screen  5  in the second embodiment is designed to have a thicker portion  5   a  than the rest of the screen  5 . The projections  12  make abutment with the screen  5  at the thicker portion  5   a  when the cellular phone is folded. 
   In place of forming the thicker portion  5   a , a piece composed of material having high stiffness may be adhered to the screen  5  such that the projections  12  make abutment with the piece. 
   The projections  12  may be integrally formed with the second body  2  by molding. As an alternative, the projections  12  as separate parts may be fixedly adhered to the second body  2 . 
   The packing  14  is composed of elastic material, and is fixedly adhered to the display  3  such that the packing  14  extends around the recess  4 . The packing  14  is fixedly adhered further to the screen  5 . 
   Hereinbelow is explained an operation of the cellular phone in accordance with the second embodiment, with reference to  FIGS. 7A ,  7 B,  8 A and  8 B. 
   By rotating the first and second bodies  1  and  2  relative to each other, the cellular phone is folded or unfolded. 
   When the cellular phone is folded, the projections  12  are kept inserted into the elongate holes  13  to make abutment with the screen  5 , resulting in that the projections  12  exert compressive force on the screen  5 . While such compressive force acts on the screen  5 , the compressive force acts also on the packing  14  fixed to the screen, and hence, the packing  14  composed of elastic material is compressed, as illustrated in  FIG. 8B . As a result, the screen  5  is pushed towards the rear case  102  of the first body  1 , ensuring a clearance between the operation keys  7  and the screen  5 . 
   When the cellular phone is unfolded, the projections  12  are pulled out of the elongate holes  13 , and hence, the compressive force does no longer act on the screen  5 . The packing  14  stores elastic energy therein while compressed. The elastic energy stored in the packing  14  causes the screen  5  to expand towards the front case  101  of the first body  1 . 
   With reference to  FIG. 8A , when the cellular phone is unfolded, the packing  14  has a thickness of T 1 , and causes the screen  5  to make contact with the front case  101  of the first body  1 . When the cellular phone is folded, the clearance D 3  (see  FIG. 5 ) is smaller than the clearance D 4  (see  FIG. 5 ). 
   In contrast, when the cellular phone is folded, the projections  12  exert compressive force on the screen  5 , and the compressive force is transferred to the packing  14  through the screen  5 . As a result, as illustrated in  FIG. 8B , a thickness of the packing  14  is shortened to the thickness T 2  from the thickness T 1 . Hence, the clearance D 3  is increased by a difference between the thicknesses T 1  and T 2 , that is, by (T 1 -T 2 ). Thus, the clearance D 3  becomes greater than the clearance D 4  defined as a clearance between the front case  103  of the second body  2  and the tops of the operation keys  7 . This ensures that the screen  5  does no longer interfere with the operation keys  7 , and accordingly, the screen is no longer damaged at a surface thereof. 
   Third Embodiment 
     FIG. 9  is a cross-sectional view of a cellular phone in accordance with the third embodiment of the present invention. 
   In the cellular phone in accordance with the second embodiment, the packing  14  is fixedly adhered to the display  3 , as illustrated in  FIGS. 8A and 8B . It should be noted that the packing  14  may be adhered to anywhere, if the packing  14  is compressed directly or indirectly by the projections  12  when the cellular phone is folded. In the third embodiment, as illustrated in  FIG. 9 , the packing  14  is fixedly adhered to the front case  101  of the first body  1 . 
   The cellular phone in accordance with the third embodiment has the same structure as that of the cellular phone in accordance with the second embodiment except the location of the packing  14 . 
   While the present invention has been described in connection with certain preferred embodiments, it is to be understood that the subject matter encompassed by way of the present invention is not to be limited to those specific embodiments. On the contrary, it is intended for the subject matter of the invention to include all alternatives, modifications and equivalents as can be included within the spirit and scope of the following claims. 
   The entire disclosure of Japanese Patent Application No. 2002-289069 filed on Oct. 1, 2002 including specification, claims, drawings and summary is incorporated herein by reference in its entirety.