Patent Publication Number: US-10777371-B1

Title: Key structure

Description:
FIELD OF THE INVENTION 
     The present invention relates to an input device, and more particularly to a key structure. 
     BACKGROUND OF THE INVENTION 
     In modern societies, electronic devices become indispensable parts in human lives. The electronic products are applied in many sectors, including food, clothing, housing, transportation, education and entertainment. For facilitating carrying and using electronic products, the trends of designing electronic products are toward light weightiness and slimness. 
     Generally, an electronic product is equipped with keys. A single key is only able to generate a single key signal. As the volume of the electronic product is gradually decreased, the number of keys is gradually reduced. Since the single key is only able to generate the single key signal, the electronic device cannot meet the requirements of diversity. 
     For overcoming the drawbacks of the conventional technologies, the present invention provides a key structure capable of generating two key signals. When the key structure is depressed, two travel distances corresponding to the two key signals are selectively provided. 
     SUMMARY OF THE INVENTION 
     The present invention provides a key structure capable of generating two key signals. When the key structure is depressed, two travel distances corresponding to the two key signals are selectively provided. 
     In accordance with an aspect of the present invention, a key structure is provided. The key structure includes a keycap, a supporting plate, a connecting element and an elastic element. The connecting element is connected with the keycap and the supporting plate. The keycap is movable upwardly or downwardly relative to the supporting plate through the connecting element. The circuit board is disposed on the supporting plate. A switch element is installed on the circuit board. The circuit board includes a first film layer, a separation layer and a second film layer. A perforation runs through the first film layer. A first switch unit of the switch element is formed on a top surface of the first film layer and arranged around the perforation. The second film layer is located under the first film layer. A second switch unit of the switch element is formed on a top surface of the second film layer. The separation layer is arranged between the first film layer and the second film layer. The separation layer has a through-hole. Moreover, two ends of the through-hole are respectively aligned with the perforation and the second switch unit. The elastic element is arranged between the keycap and the circuit board, and aligned with the switch element. The elastic element includes a conductive pressing part. The conductive pressing part includes an end surface and a raised block. The raised block is disposed on the end surface. When the keycap is depressed in response to an external force, the elastic element is subjected to deformation and the conductive pressing part is moved downwardly, and the end surface of the conductive pressing part is contacted with the first switch unit. Consequently, a first key signal is generated. When the keycap is continuously depressed in response to the external force, the raised block is penetrated through the perforation and contacted with the second switch unit. Consequently, a second key signal is generated. 
     In an embodiment, the elastic element further includes an elastic supporting part and a contacting part. The contacting part and the conductive pressing part are respectively located at opposite sides of the elastic supporting part. The contacting part is in contact with the keycap, and the elastic supporting part is fixed on the first film layer to provide an elastic restoring force to the keycap. 
     In an embodiment, the first switch unit includes a first conductive part and a second conductive part. The first conductive part and the second conductive part are respectively located beside two opposite sides of the perforation. 
     In an embodiment, the first conductive part and the second conductive part are semicircular-arc parts and arranged around the perforation. 
     In an embodiment, the second switch unit includes a third conductive part and a fourth conductive part, which are arranged beside each other. 
     In an embodiment, the third conductive part and the fourth conductive part are semicircular-arc parts and arranged in a staggered form. 
     In an embodiment, the key structure further includes a resilience element. The resilience element is arranged between the elastic element and the keycap and provides an additional traveling distance. 
     In an embodiment, the connecting element includes a first frame and a second frame. 
     In an embodiment, the elastic element is a one-piece conductive rubber structure. 
     In accordance with another aspect of the present invention, a key structure is provided. The key structure includes a keycap, a supporting plate, a connecting element and an elastic element. The connecting element is connected with the keycap and the supporting plate. The keycap is movable upwardly or downwardly relative to the supporting plate through the connecting element. The circuit board is disposed on the supporting plate. A switch element is installed on the circuit board. The circuit board includes a first film layer, a first separation layer, a second film layer, a second separation layer and a third film layer. A conductive layer of the switch element is formed on a bottom surface of the first film layer. The second film layer is located under the first film layer. A perforation runs through the second film layer. A first switch unit of the switch element is formed on a top surface of the second film layer and arranged around the perforation. The third film layer is located under the second film layer. A second switch unit of the switch element is formed on a top surface of the third film layer. The first separation layer is arranged between the first film layer and the second film layer. The first separation layer has a first through-hole. Moreover, two ends of the first through-hole are respectively aligned with the conductive layer and the first switch unit, the second separation layer is arranged between the second film layer and the third film layer. The second separation layer has a second through-hole. Moreover, two ends of the second through-hole are respectively aligned with the perforation and the second switch unit. The elastic element is arranged between the keycap and the circuit board, and aligned with the switch element, wherein the elastic element includes a pressing part. When the keycap is depressed in response to an external force, the elastic element is subjected to deformation and the pressing part is moved downwardly to press the first film layer, and the conductive layer is contacted with the first switch unit. Consequently, a first key signal is generated. When the keycap is continuously depressed in response to the external force, a portion of the conductive layer is penetrated through the perforation and contacted with the second switch unit. Consequently, a second key signal is generated. 
     In an embodiment, the elastic element further includes an elastic supporting part and a contacting part. The contacting part and the pressing part are respectively located at opposite sides of the elastic supporting part. The contacting part is in contact with the keycap. The elastic supporting part is fixed on the first film layer to provide an elastic restoring force to the keycap. 
     In an embodiment, the first switch unit includes a first conductive part and a second conductive part. The first conductive part and the second conductive part are respectively located beside two opposite sides of the perforation. 
     In an embodiment, the first conductive part and the second conductive part are semicircular-arc parts and arranged around the perforation. 
     In an embodiment, the second switch unit includes a third conductive part and a fourth conductive part, which are arranged beside each other. 
     In an embodiment, the third conductive part and the fourth conductive part are semicircular-arc parts and arranged in a staggered form. 
     In an embodiment, the key structure further includes a resilience element. The resilience element is arranged between the elastic element and the keycap and provides an additional traveling distance. 
     In an embodiment, the connecting element includes a first frame and a second frame. 
     According to the benefits of the present invention, a single key is capable of generating two key signals. When the key structure is depressed, the travel distances corresponding to the two key signals are selectively provided. 
     The above objects and advantages of the present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed description and accompanying drawings, in which: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a schematic perspective view illustrating a key structure according to a first embodiment of the present invention; 
         FIG. 1B  is a schematic exploded view illustrating the key structure according to the first embodiment of the present invention; 
         FIG. 2  is a schematic exploded view illustrating the relationship between the circuit board and the elastic element of the key structure according to the first embodiment of the present invention; 
         FIG. 3  schematically illustrates the operations of the key structure according to the first embodiment of the present invention; 
         FIG. 4  is a schematic exploded view illustrating a key structure according to a second embodiment of the present invention; 
         FIG. 5  is a schematic exploded view illustrating the relationship between the circuit board and the elastic element of the key structure according to the second embodiment of the present invention; 
         FIG. 6  schematically illustrates the operations of the key structure according to the second embodiment of the present invention; 
         FIG. 7  is a schematic exploded view illustrating a key structure according to a third embodiment of the present invention; and 
         FIG. 8  schematically illustrates the operations of the key structure according to the third embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention will now be described more specifically with reference to the following embodiments. It is to be noted that the following descriptions of preferred embodiments of this invention are presented herein for purpose of illustration and description only. It is not intended to be exhaustive or to be limited to the precise form disclosed. 
     Please refer to  FIG. 1A  and  FIG. 1B .  FIG. 1A  is a schematic perspective view illustrating a key structure according to a first embodiment of the present invention.  FIG. 1B  is a schematic exploded view illustrating the key structure according to the first embodiment of the present invention. The key structure  1  comprises a keycap  10 , a connecting element  20 , an elastic element  30 , a circuit board  40 , a switch element  50  and a supporting plate  60 . The switch element  50  is installed on the circuit board  40 . The circuit board  40  is disposed on the supporting plate  60 . The elastic element  30  is arranged between the keycap  10  and the circuit board  40  and aligned with the switch element  50 . The elastic element  30  is enclosed by the connecting element  20 . Moreover, the keycap  10  and the supporting plate  60  are connected with each other through the connecting element  20 . 
     Please refer to  FIG. 1B . The keycap  10  comprises first coupling parts  101  and second coupling parts  102 . The first coupling parts  101  and the second coupling parts  102  are protruded from a bottom surface of the keycap  101 . The connecting element  20  comprises a first frame  21  and a second frame  22 . The first frame  21  has a first end  211  and a second end  212 . The second frame  22  has a first end  221  and a second end  222 . The supporting plate  60  comprises third couplings  601  and fourth coupling parts  602 . The third couplings  601  and the fourth coupling parts  602  are penetrated through or exposed to corresponding board openings O of the circuit board  40 . 
     For assembling the key structure  1 , the first frame  21  and the second frame  22  of the connecting element  20  are pivotally coupled to each other through a rotation shaft (not shown). The first end  211  of the first frame  21  is pivotally coupled to the first coupling parts  101  of the keycap  10 . The second end  212  of the first frame  21  is pivotally coupled to the fourth coupling parts  602  of the supporting plate  60 . The first end  221  of the second frame  22  is pivotally coupled to the second coupling parts  102  of the keycap  10 . The second end  222  of the second frame  22  is pivotally coupled to the third couplings  601  of the supporting plate  60 . Consequently, the first frame  21  and the second frame  22  are rotatably connected between the keycap  10  and the supporting plate  60 , and the keycap  10  is driven and guided to be ascended or descended relative to the supporting plate  60 . In an embodiment, the connecting element  20  is a scissors-type connecting element. It is noted that the example of the connecting element is not restricted. In another embodiment, the connecting element includes a V-shaped linkage, an A-shaped linkage or two parallel linkages. 
       FIG. 2  is a schematic exploded view illustrating the relationship between the circuit board and the elastic element of the key structure according to the first embodiment of the present invention. As shown in  FIG. 2 , the elastic element  30  comprises an elastic supporting part  31 , a contacting part  32  and a conductive pressing part  33 . The elastic supporting part  31  has a dome shape. The conductive pressing part  33  is located at a top end of an inner space of the elastic supporting part  31 . Moreover, the conductive pressing part  33  is aligned with the switch element  50 . The contacting part  32  and the conductive pressing part  33  are located at opposite sides of the elastic supporting part  31 , respectively. The contacting part  32  is in contact with the bottom surface of the keycap  10  (see  FIG. 1B ). The elastic element  30  is a one-piece conductive rubber structure. A first end of the conductive pressing part  33  away from the contacting part  32  has an end surface  331 . A raised block  34  is disposed on the end surface  331  of the conductive pressing part  33 . Moreover, a bottom of the elastic supporting part  31  comprises a fixing end  311 . 
     From top to bottom, the circuit board  40  comprises a first film layer  41 , a separation layer  42  and a second film layer  43  sequentially. The first film layer  41  comprises a perforation  411 . The perforation  411  runs through a top surface and a bottom surface of the first film layer  41 . A first switch unit  51  of the switch element  50  is formed on the top surface of the first film layer  41  and arranged around the perforation  411 . The second film layer  43  is located under the first film layer  41 . A second switch unit  52  of the switch element  50  is formed on a top surface of the second film layer  43 . The separation layer  42  is arranged between the first film layer  41  and the second film layer  43 . The separation layer  42  has a through-hole  421 . The two ends of the through-hole  421  are aligned with the perforation  411  and the second switch unit  52 , respectively. 
     The first switch unit  51  comprises a first conductive part  511  and a second conductive part  512 . The second switch unit  52  comprises a third conductive part  521  and a fourth conductive part  522 , which are arranged beside each other. In this embodiment, the first conductive part  511  and the second conductive part  512  are located beside two opposite sides of the perforation  411 , respectively. Moreover, the first conductive part  511  and the second conductive part  512  are semicircular-arc parts and arranged around the perforation  411 . The third conductive part  521  and the fourth conductive part  522  are semicircular-arc parts and arranged in a staggered form. 
     Please refer to  FIG. 3 .  FIG. 3  schematically illustrates the operations of the key structure according to the first embodiment of the present invention. 
     In the situation (i) of  FIG. 3 , the fixing end  311  of the elastic supporting part  31  is fixed on the top surface of the first film layer  41  in an adhering manner, and thus the elastic element  30  is fixed on the circuit board  40 . The contacting part  32  is in contact with the bottom surface of the keycap  10 . The contacting part  32  provides an elastic restoring force to the keycap  10  through the elastic supporting part  31 . The raised block  34  of the conductive pressing part  33  is aligned with the perforation  411  and the second switch unit  52 . The portion of the end surface  331  around the raised block  34  is aligned with the first switch unit  51 . 
     In the situation (ii) of  FIG. 3 , an external force F is applied to the keycap  10 . In response to the external force F, the keycap  10  is depressed to compress the elastic element  30 . Consequently, the elastic element  30  is subjected to deformation, and the conductive pressing part  33  is moved downwardly. When the end surface  331  of the conductive pressing part  33  is contacted with the first conductive part  511  and the second conductive part  512  of the first switch unit  51 , the conductive pressing part  33  is electrically connected with the first conductive part  511  and the second conductive part  512 . Consequently, a first key signal S 1  is generated. 
     In the situation (iii) of  FIG. 3 , the external force F is continuously applied to the keycap  10 . In response to the external force F, the conductive pressing part  33  is moved downwardly and continuously. Then, the raised block  34  is penetrated through the perforation  411 . When the raised block  34  is contacted with the third conductive part  521  and the fourth conductive part  522  of the second switch unit  52 , the conductive pressing part  33  is electrically connected with the third conductive part  521  and the fourth conductive part  522 . Consequently, a second key signal S 2  is generated. 
     As mentioned above, the elastic element  30  is a one-piece conductive rubber structure. Consequently, the entire of the elastic element  30  is electrically conductive. It is noted that numerous modifications and alterations may be made while retaining the teachings of the invention. For example, in another embodiment, the elastic supporting part  31  and contacting part  32  are made of nonconductive elastic material. That is, only the conductive pressing part  33  is made of conductive elastic material or conductive non-elastic material. 
     Please refer to  FIGS. 4 and 5 .  FIG. 4  is a schematic exploded view illustrating a key structure according to a second embodiment of the present invention.  FIG. 5  is a schematic exploded view illustrating the relationship between the circuit board and the elastic element of the key structure according to the second embodiment of the present invention. As shown in  FIG. 4 , the key structure  1  comprises a keycap  10 , a connecting element  20 , an elastic element  30 ′, a circuit board  40 ′, a switch element  50 ′ and a supporting plate  60 . The structures and functions of the keycap  10 , the connecting element  20  and the supporting plate  60  are similar to those of the first embodiment, and are not redundantly described herein. 
     In this embodiment, the elastic element  30 ′ is made of nonconductive elastic material such as rubber or silicone. As shown in  FIG. 5 , the elastic element  30 ′ comprises an elastic supporting part  31 ′, a contacting part  32 ′ and a pressing part  33 ′. The elastic supporting part  31 ′ has a dome shape. The pressing part  33 ′ is located at a top end of an inner space of the elastic supporting part  31 ′. Moreover, the pressing part  33 ′ is aligned with the switch element  50 ′. The contacting part  32 ′ and the pressing part  33 ′ are located at opposite sides of the elastic supporting part  31 ′, respectively. The contacting part  32 ′ is in contact with the bottom surface of the keycap  10  (see  FIG. 4 ). An end of the pressing part  33 ′ away from the contacting part  32 ′ has an end surface  331 ′. 
     From top to bottom, the circuit board  40 ′ comprises a first film layer  41 ′, a first separation layer  42 ′, a second film layer  43 ′, a second separation layer  44 ′ and a third film layer  45 ′ sequentially. 
     A conductive layer  51 ′ of the switch element  50 ′ is formed on a bottom surface of the first film layer  41 ′. The second film layer  43 ′ comprises a perforation  431 ′. The perforation  431 ′ runs through a top surface and a bottom surface of the second film layer  43 ′. A first switch unit  52 ′ of the switch element  50 ′ is formed on the top surface of the second film layer  43 ′ and arranged around the perforation  431 ′. The third film layer  45 ′ is located under the second film layer  43 ′. A second switch unit  53 ′ of the switch element  50 ′ is formed on a top surface of the third film layer  45 ′. The first separation layer  42 ′ is arranged between the first film layer  41 ′ and the second film layer  43 ′. The first separation layer  42 ′ has a first through-hole  421 ′. The two ends of the first through-hole  421 ′ are aligned with the conductive layer  51 ′ and the first switch unit  52 ′, respectively. The second separation layer  44 ′ is arranged between the second film layer  43 ′ and the third film layer  45 ′. The second separation layer  44 ′ has a second through-hole  441 ′. The two ends of the second through-hole  441 ′ are aligned with the perforation  431 ′ and the second switch unit  53 ′, respectively. 
     The first switch unit  52 ′ comprises a first conductive part  521 ′ and a second conductive part  522 ′. The second switch unit  53 ′ comprises a third conductive part  531 ′ and a fourth conductive part  532 ′, which are arranged beside each other. In this embodiment, the first conductive part  521 ′ and the second conductive part  522 ′ are located beside two opposite sides of the perforation  431 ′, respectively. Moreover, the first conductive part  521 ′ and the second conductive part  522 ′ are semicircular-arc parts and arranged around the perforation  431 ′. The third conductive part  531 ′ and the fourth conductive part  532 ′ are semicircular-arc parts and arranged in a staggered form. 
     Please refer to  FIG. 6 .  FIG. 6  schematically illustrates the operations of the key structure according to the second embodiment of the present invention. 
     In the situation (i) of  FIG. 6 , the fixing end  311 ′ of the elastic supporting part  31  is fixed on the top surface of the first film layer  41 ′ in an adhering manner, and thus the elastic element  30 ′ is fixed on the circuit board  40 ′. The contacting part  32 ′ is in contact with the bottom surface of the keycap  10 . The contacting part  32 ′ provides an elastic restoring force to the keycap  10  through the elastic supporting part  31 ′. The end surface  331 ′ of the pressing part  33 ′ is aligned with the conductive layer  51 ′ of the switch element  50 ′. 
     In the situation (ii) of  FIG. 6 , an external force F is applied to the keycap  10 . In response to the external force F, the keycap  10  is depressed to compress the elastic element  30 ′. Consequently, the elastic element  30 ′ is subjected to deformation, and the pressing part  33 ′ is moved downwardly. When the end surface  331 ′ of the pressing part  33 ′ is contacted with the top surface of the first film layer  41 ′ and the conductive layer  51 ′ on the bottom surface of the first film layer  41 ′ is contacted with first conductive part  521 ′ and the second conductive part  522 ′ of the first switch unit  52 ′, the conductive layer  51 ′ is electrically connected with the first conductive part  521 ′ and the second conductive part  522 ′. Consequently, a first key signal S 1  is generated. 
     In the situation (iii) of  FIG. 6 , the external force F is continuously applied to the keycap  10 . In response to the external force F, the pressing part  33 ′ is moved downwardly and continuously. Then, a portion of the conductive layer  51 ′ is penetrated through the perforation  431 ′. When the conductive layer  51 ′ is contacted with the third conductive part  531 ′ and the fourth conductive part  532 ′ of the second switch unit  53 ′, the conductive layer  51 ′ is electrically connected with the third conductive part  531 ′ and the fourth conductive part  532 ′. Consequently, a second key signal S 2  is generated. 
     Please refer to  FIGS. 7 and 8 .  FIG. 7  is a schematic exploded view illustrating a key structure according to a third embodiment of the present invention.  FIG. 8  schematically illustrates the operations of the key structure according to the third embodiment of the present invention. As shown in  FIG. 7 , the key structure  1  comprises a keycap  10 , a connecting element  20 , an elastic element  30 ′, a circuit board  40 ′, a switch element  50 ′, a supporting plate  60  and a resilience element  70 . The structures and functions of the keycap  10 , the connecting element  20 , the elastic element  30 ′, the circuit board  40 ′, the switch element  50 ′ and the supporting plate  60  are similar to those of the second embodiment, and are not redundantly described herein. In comparison with the second embodiment, the key structure  1  of this embodiment further comprises the resilience element  70 . The resilience element  70  is arranged between the elastic element  30 ′ and the keycap  10 . For example, the resilience element  70  is a metal dome. 
     In the situation (i) of  FIG. 8 , a first side of the resilience element  70  is contacted with the contacting part  32 ′ of the elastic element  30 ′, and a second side of the resilience element  70  is contacted with the bottom surface of the keycap  10 . 
     In the situation (ii) of  FIG. 8 , an external force F is applied to the keycap  10 . In response to the external force F, the elastic element  30 ′ is subjected to deformation. Consequently, a travel distance is provided (see  FIG. 6 ( ii )), and a first key signal S 1  is generated (see  FIG. 6 ( ii )). 
     In the situation (iii) of  FIG. 8 , the external force F is continuously applied to the keycap  10 . In response to the external force F, the resilience element  70  is subjected to deformation. Consequently, another travel distance is provided (see  FIG. 6 ( iii )), and a second key signal S 2  is generated (see  FIG. 6 ( iii )). 
     In this embodiment, the resilience element  70  is fixed on the elastic element  30 ′. It is noted that numerous modifications and alterations may be made while retaining the teachings of the invention. For example, in another embodiment, the elastic element  30 ′ is fixed on the bottom surface of the keycap  10 . Moreover, the key structure  1  of the first embodiment may be equipped with the resilience element  70  to generate the additional travel distance. 
     From the above descriptions, the circuit board of the key structure comprises plural film layers. The switch units are installed on the plural film layers. Consequently, a single key is capable of generating two key signals. Moreover, due to the elastic element and the resilience element, the travel distances corresponding to the two key signals are generated. In other words, the technologies of the present invention are industrially valuable. 
     While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all modifications and similar structures.