Patent Publication Number: US-2007108033-A1

Title: Slender keyswitch structure

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a keyswitch structure, and more particularly, to a slender keyswitch structure applied to a mobile electronic apparatus which is slim and slight.  
      2. Description of the Prior Art  
      Generally speaking, keyswitches are sited on an electronic apparatus, and more particularly, on a mobile electronic apparatus, so as to facilitate users in the manipulation of these electronic apparatus.  
      For instance, a shutter keyswitch sited on a camera is a necessary keyswitch and is the most important user interface when users take photographs. Therefore, one of the most critical requirements in selecting a camera is whether the shutter keyswitch is easy to be manipulated and whether the quality of the photograph is affected by the shutter keyswitch when it is manipulated. In accordance with the requirements above, the shutter keyswitches applied to cameras are generally made in simple designs, such as circular or fat shape.  
      With respect to the shutter of the camera of the prior art, a compressed spring is sited under a circular or a fat keycap. The compressed spring supports the keycap to create the sense of taction when users press the shutter keyswitch. In the prior art, the spring is sited under the center of the keycap, and a constant preload is provided when the keyswitch is assembled. After the assembly of the camera is finished, the spring given a preload is capable of supporting the shutter keyswitch, and it provides users with the sense of taction when users press the shutter. During the process of each press, the compressed spring can evenly acts on the circumference of the circular or fat keycap, effectively cooperate with the switch of the keyswitch and recoil back to its original state.  
      Since the shutter keyswitch in prior art is actuated by a compress spring cooperating with a circular or fat keycap, the upward force produced by the compressed spring has to evenly act on the circumference of the circular or fat keycap to effectively support the keycap; this cooperation can avoid the circumstances that the shutter keyswitch slants from the center position or that the sense of taction in manipulation is not good. On the other hand, at present, the design of electronic apparatus is preferred to be slim and slight. This design easily creates a problem of inadequate inner space. In order to facilitate manipulation, the traditional circular or fate keycap has to be transformed into a slender one which occupies less space and increases the surface area for manipulation. However, if the slender keycap of the shutter keyswitch cooperates with traditional compressed spring structure, many undesirable circumstances may occur, resulting in the shutter keyswitch not being able to work smoothly or even failing to work. These circumstances include the keycap not being able to actuate the inner switch, users having bad sense of taction in manipulation, and the keycap contacting the switch abnormally . . . , and so forth.  
      Accordingly, a scope of the invention is to provide a keyswitch structure, so as to solve the problem mentioned above.  
     SUMMARY OF THE INVENTION  
      A scope of the invention is to provide a keyswitch structure and, more particularly, a slender keyswitch structure especially applied to a mobile electronic apparatus which is slim and slight.  
      According to a preferred embodiment of the present invention, a keyswitch structure is disposed on an electronic apparatus. The electronic apparatus includes a casing having an outer wall and an inner wall opposite to the outer wall. A through hole is formed on the outer wall. Besides, the keyswitch structure also includes a keycap, a resilient member, and a switch. Moreover, the keycap includes a press portion and an engagement portion. The engagement portion protrudes from a circumference of the press portion and is movably limited by the outer wall. The press portion includes a projection formed on an inner surface thereof. The keycap is substantially disposed in the hole of the outer wall such that the press portion is partially exposed outside the hole. The resilient member includes at least one fixed portion and a plurality of resilient ends. All of the at least one fixed portions is fixed on the inner wall. Besides, the resilient ends of the resilient member abuts against the keycap and supports the keycap to vertically move along the inner wall. Finally, the switch is disposed on the inner wall, too. When an external force acts on the press portion of the keycap, the keycap compresses the resilient member such that the resilient ends of the resilient member slide on the keycap, and that the projection is actuated by the keycap to turn on the switch.  
      The advantage and spirit of the invention may be further understood by the following recitations together with the appended drawings. 
    
    
     BRIEF DESCRIPTION OF THE APPENDED DRAWINGS  
       FIG. 1A  is a vertical view illustrating the keyswitch structure  12  according to a preferred embodiment of the invention.  
       FIG. 1B  is a cross-sectional view illustrating the keyswitch structure  12  in  FIG. 1A  along the A-A line.  
       FIG. 1C  is a cross-sectional view illustrating the keyswitch structure  12  in  FIG. 1B  along the B-B line.  
       FIG. 2  is an upward view illustrating the keyswitch structure  12  according to the invention.  
       FIG. 3A  is a schematic diagram, in accordance with the invention, illustrating the state that the keyswitch structure  12  is not under an external force.  
       FIG. 3B  is a schematic diagram, in accordance with the invention, illustrating the state that the center of the slender keycap  16  of the keyswitch structure  12  is not under an external force pressed against it.  
       FIG. 3C  is a schematic diagram, in accordance with the invention, illustrating the state that the right side of the slender keycap  16  of the keyswitch structure  12  is not under an external force pressed against it. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      Referring to  FIG. 1A  to  1 C and  FIG. 2 , a keyswitch structure  12  according to a preferred embodiment of the invention is shown in these figures.  
       FIG. 1A  is a vertical view illustrating the keyswitch structure  12  according to the preferred embodiment of the invention; it also illustrates a part of the casing of an electronic apparatus  10  installed with the keyswitch structure  12 . The casing has an outer wall  14  and an inner wall  15 , which is illustrated in  FIG. 1C , opposite to the outer wall. Besides, a through hole  146  is formed on the outer wall  14 . In an embodiment, the electronic apparatus  10  is a mobile electronic apparatus, such as a camera.  
       FIG. 1B  is a cross-sectional view illustrating the keyswitch structure  12  in  FIG. 1A  along the A-A line.  FIG. 1C  is a cross-sectional view illustrating the keyswitch structure  12  in  FIG. 1B  along the B-B line.  FIG. 2  is an upward view illustrating the keyswitch structure  12 . As shown in  FIG. 1A ,  FIG. 1B ,  FIG. 1C  and  FIG. 2 , the keyswitch structure  12  includes a keycap  16 , a resilient member  18  and a switch  13 .  
      As show in  FIG. 1B ,  FIG. 1C , and  FIG. 2 , the outer wall  14  includes a base portion  142  and a protrusion portion  144 , whereon the through hole  146  is formed. The protrusion portion  144  outwardly protrudes from the base portion  142  to the outside of the electronic apparatus  10 , forming an accommodating space. Besides, the keycap  16  is sited in the accommodating space of the outer wall  14 .  
      As shown in  FIG. 1B ,  FIG. 1C , and  FIG. 2 , the keycap  16  includes a press portion  24  and an engagement portion  26  protruding from a circumference of the press portion  24 . The keycap  16  is substantially disposed in the through hole  146  of the outer wall such that the press portion  24  is partially exposed outside the through hole  146 , and that the engagement portion  26  is movably limited by the outer wall  14 . Furthermore, a projection  30  is sited on an inner surface of the press portion  24 .  
      In an embodiment, the keycap  16  is a slender keycap.  
      As shown in  FIG. 1B ,  FIG. 1C  and  FIG. 2 , the resilient member  18  includes at least one fixed portion  32  and a plurality of resilient ends  34 . All of the at least one fixed portions  32  is fixed on the inner wall  15 . The plurality of resilient ends  34  of the resilient member  18  abuts against the keycap  16  and supports the keycap  16  to vertically move along the inner wall  15 .  
      In an embodiment, as shown in  FIG. 1B ,  FIG. 1C  and  FIG. 2 , the engagement portion  26  thereon forms a plurality of guiding grooves  28 . Each of the resilient ends  34  of the resilient member  18  is slidablly disposed in one of the guiding grooves  28 . Therefore, in the process that the keycap  16  vertically moves along the inner wall  15 , the plurality of resilient ends  34  guided by the plurality of grooves  28  slides linearly.  
      In an embodiment, as shown in  FIG. 1B ,  FIG. 1C  and  FIG. 2 , the plurality of the resilient ends  34  of the resilient member  18  linearly contact the keycap  16  to improve the rigidity of the plurality of the resilient ends  34 . Therefore, in the process that the keycap  16  vertically moves along the inner wall  15 , the plurality of resilient ends  34  slides with less friction relative to the keycap  16 , so as to improve the tactile feeling and smoothness of the keyswitch structure  12  in manipulation.  
      In an embodiment, the resilient member  18  is made from a thin steel plate.  
      In an embodiment, as shown in  FIG. 1B ,  FIG. 1C , and  FIG. 2 , the resilient member  18  also includes a plurality of resilient arms, each of which protrudes from one of the at least one fixed portion  32 . Besides, each of the resilient ends  34  is formed on one of the resilient arms.  
      The switch  13  is disposed on the inner wall  15 . When an external force acts on the press portion  24  of the keycap  16 , the keycap  16  compresses the resilient member  18  so that the resilient ends  34  of the resilient member  18  slide on the keycap  16 , and that the projection  30  is actuated by the keycap  16  to turn on the switch  13 .  
      In an embodiment, as shown in  FIG. 1B ,  FIG. 1C  and  FIG. 2 , the casing further includes a plurality of position bosses  40 . The plurality of position bosses  40  protrudes from the base  142  of the outer wall  14  toward the accommodating space to block the keycap  16  from sliding out of the accommodating space. In another embodiment, the casing further includes a plurality of position bosses  40 . The plurality of position bosses  40  protrudes from the protrusion portion  144  of the outer wall  14  toward the accommodating space to block the keycap  16  from sliding out of the accommodating space by a slanted force, as shown in  FIG. 3C .  
      Referring to  FIG. 3A ,  FIG. 3B  and  FIG. 3C , according to the invention, these figures illustrate all states of the slender keycap  16  sited on the keyswitch structure  12  whether it is acted upon by an external force or not.  FIG. 3A , in accordance with the invention, illustrates the state that the keyswitch structure  12  is not under an external force. As shown in  FIG. 3A , the slender keycap  16  is supported by the resilient member  18 ; the press portion  24  of the slender keycap  16  is partially exposed outside the through hole  146  of the outer wall  14 .  
      According to the invention,  FIG. 3B  illustrates the state that the slender keycap  16  of the keyswitch structure  12  is receiving an external force, which is marked by an arrow in the figure, against the center of the keycap  16 . As shown in  FIG. 3B , at this time, the resilient arm of the resilient member  18  connecting with the resilient ends  34  synchronously has downward and even deformation (moving to the horizontal line marked by a dotted line), with the fulcrum at the fixed portion  32  of the resilient member  18 . The evenly deformed resilient arms provide a sense of taction for users, and they also provide the kinetic energy which makes the slender keycap  16  recoil back to the original position after the external force is removed. Under these circumstances, the projection  30  sited on the slender keycap  16  is effectively actuated by the keycap  16  to turn on the switch  13 .  
      According to the invention,  FIG. 3C  illustrates the state that the slender keycap  16  of the keyswitch structure  12  is receiving an external force, which is marked by an arrow in the figure, against the right side of the keycap  16 . As shown in  FIG. 3C , besides one fulcrum at the fixed portion  32  of the resilient member  18 , another fulcrum is formed by the resilient ends  34  which get stuck with the position boss  40 . The slender keycap  16  will tilt toward its right side, and the resilient arm of the resilient member  18  on the right will have much more deformation. On the other hand, the resilient arm of the resilient member  18  on the left has almost no deformation. Only the arm on the right provides a sense of taction for users, and it also provides the kinetic energy which makes the slender keycap  16  recoil back to the original position after the external force is removed. Under these circumstances, the projection  30  sited on the slender keycap  16  is effectively actuated by the keycap  16  to turn on the switch  13 .  
      With the recitations regarding the execution of the invention, it clearly shows that the problems expected in the prior art will not easily occur, even if the slender keyswitch in accordance with the invention is pressed at its periphery. These problems include the keycap not being able to actuate the inner switch, users having bad sense of taction in manipulation, users pressing the keyswitch imprudently, and the keycap contacting the switch abnormally . . . , and so forth. Compared with traditional keyswitch cooperating with compressed spring, and circular or fat keycap, the keyswitch structure in accordance with this invention has better reinstatement and more room for shape design.  
      With the recitations of the preferred embodiment above, the features and spirits of the invention will be hopefully well described, but the scope of the invention will not be constrained. However, the objective is expected to cover all alternative and equivalent arrangements in the scope of the appended claims for which the invention apply.