Patent Publication Number: US-11651912-B1

Title: Control device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to U.S. Provisional Patent Application No. 63/318,415 filed Mar. 10, 2022, the contents of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a control device, and more particularly to a control device with a display panel and at least one light-transmissible key structure. 
     BACKGROUND OF THE INVENTION 
     A control device is widely used in a live streaming machine, a live production switcher, an ordering machine or a drawing device. The control device comprises a display panel and plural light-transmissible key structures. Due to the cooperation of the display panel and the light-transmissible key structures, the control device has the visualized buttons for facilitating the user to select desired items and perform associated operations in an intuitive manner. 
     It is an important issue for the manufacturer to install a suitable key structure in the control device. 
     SUMMARY OF THE INVENTION 
     In order to overcome the drawbacks of the conventional technologies, the present invention provides a control device. The key structure of the control device is designed according to a pressure-sensitive technology. 
     In accordance with an aspect of the present invention, a control device is provided. The control device includes a display panel and a key structure. The key structure is located over the display panel. The key structure includes a circuit board, a keycap, an elastic element and a conducting element. The circuit board includes a first top surface, a circuit structure and a first opening. The circuit structure is installed on the first top surface and arranged around the first opening. The circuit structure includes a first circuit pattern and a second circuit pattern. The first circuit pattern and the second circuit pattern are separated from each other by a gap. The keycap is light-transmissible. The elastic element includes a support part, a lateral wall, a lower part and a second opening. The support part includes a second top surface and a bottom surface. The second top surface of the support part is upwardly connected with the keycap. The lateral wall is arranged between the support part and the lower part. The support part and the lateral wall are arranged around the second opening. The lower part is contacted with the circuit board. The conducting element is disposed on the bottom surface of the support part. When the keycap is pressed down, the keycap is moved downwardly to push the support part. After the support part is moved downwardly for a specified travel distance, the conducting element is contacted with the first circuit pattern and the second circuit pattern. Consequently, the first circuit pattern and the second circuit pattern are electrically connected with each other. 
     In an embodiment, the display panel emits a light beam, and the light beam is upwardly transmitted through the first opening, the second opening and the keycap. 
     In an embodiment, the conducting element is a metal sheet, a conductive rubber sheet, a carbon film, a conductive glue or a conductive foam. 
     In an embodiment, the conducting element is formed on the bottom surface of the support part by a carbon printing process, a spraying process, a coating process or an injection process. 
     In an embodiment, each of the first circuit pattern and the second circuit pattern has an L-shaped profile, an annular profile or a concave-convex staggered profile. 
     In accordance with another aspect of the present invention, a control device is provided. The control device includes a display panel and a key structure. The key structure is located over the display panel. The key structure includes a circuit board, a keycap and an elastic element. The circuit board includes a first top surface, a circuit structure and a first opening. The circuit structure is installed on the first top surface and arranged around the first opening. The circuit structure includes a first circuit pattern and a second circuit pattern. The first circuit pattern and the second circuit pattern are separated from each other by a gap. The keycap is light-transmissible. The elastic element includes a support part, a lateral wall, a lower part and a second opening. The support part includes a second top surface and a bottom surface. The second top surface of the support part is upwardly connected with the keycap. The lateral wall is arranged between the support part and the lower part. The support part and the lateral wall are arranged around the second opening. The lower part is contacted with the circuit board. The support part is electrically conductive. When the keycap is pressed down, the keycap is moved downwardly to push the support part. After the support part is moved downwardly for a specified travel distance, the bottom surface of the support part is contacted with the first circuit pattern and the second circuit pattern. Consequently, the first circuit pattern and the second circuit pattern are electrically connected with each other. 
     In an embodiment, the display panel emits a light beam, and the light beam is upwardly transmitted through the first opening, the second opening and the keycap. 
     In an embodiment, the support part is made of a conductive material. 
     In an embodiment, the support part is doped with a conductive material. 
     In an embodiment, each of the first circuit pattern and the second circuit pattern has an L-shaped profile, an annular profile or a concave-convex staggered profile. 
     In accordance with another aspect of the present invention, a control device is provided. The control device includes a display panel and a key structure. The key structure is located over the display panel. The key structure includes a keycap, an elastic element, a conducting element and a circuit board. The keycap is made of a light-transmissible material. The keycap includes a press surface, a wall part and a pedestal. The pedestal is horizontally and externally protruded from the wall part. The pedestal includes a top surface. The elastic element includes a support part, a lateral wall, a lower part and an opening. The support part is connected with the keycap. The lateral wall is arranged between the support part and the lower part. The support part and the lateral wall are arranged around the opening of the elastic element. The conducting element is disposed on the top surface of the pedestal or the support part. The circuit board is located over the elastic element. The circuit board includes a top surface, a circuit structure, an opening and a bottom surface. The circuit structure is installed on the bottom surface of the circuit board and arranged around the opening of the circuit board. The circuit structure includes a first circuit pattern and a second circuit pattern. The first circuit pattern and the second circuit pattern are separated from each other by a gap. When the keycap is not pressed down, the conducting element is contacted with the first circuit pattern and the second circuit pattern. Consequently, the first circuit pattern and the second circuit pattern are electrically connected with each other. When the keycap is pressed down, the conducting element is detached from the first circuit pattern and the second circuit pattern. Consequently, the first circuit pattern and the second circuit pattern are not electrically connected with each other. 
     In an embodiment, the display panel emits a light beam, and the light beam is upwardly transmitted through the opening of the elastic element, the opening of the circuit board and the keycap. 
     In an embodiment, the conducting element is a metal sheet, a conductive rubber sheet, a carbon film, a conductive glue or a conductive foam. 
     In an embodiment, the conducting element is formed on the pedestal or the support part by a carbon printing process, a spraying process, a coating process or an injection process. 
     In an embodiment, each of the first circuit pattern and the second circuit pattern has an L-shaped profile, an annular profile or a concave-convex staggered profile. 
     In accordance with another aspect of the present invention, a control device is provided. The control device includes a display panel and a key structure. The key structure is located over the display panel. The key structure includes a keycap, an elastic element and a circuit board. The keycap is made of a light-transmissible material. The keycap includes a press surface, a wall part and a pedestal. The pedestal is horizontally and externally protruded from the wall part. The pedestal includes a top surface. The elastic element includes a support part, a lateral wall, a lower part and an opening. The support part is connected with the keycap. The lateral wall is arranged between the support part and the lower part. The support part and the lateral wall are arranged around the opening of the elastic element. The support part is electrically conductive. The circuit board is located over the elastic element. The circuit board includes a top surface, a circuit structure, an opening and a bottom surface. The circuit structure is installed on the bottom surface of the circuit board and arranged around the opening of the circuit board. The circuit structure includes a first circuit pattern and a second circuit pattern. The first circuit pattern and the second circuit pattern are separated from each other by a gap. When the keycap is not pressed down, the support part is contacted with the first circuit pattern and the second circuit pattern. Consequently, the first circuit pattern and the second circuit pattern are electrically connected with each other. When the keycap is pressed down, the support part is detached from the first circuit pattern and the second circuit pattern. Consequently, the first circuit pattern and the second circuit pattern are not electrically connected with each other. 
     In an embodiment, the display panel emits a light beam, and the light beam is upwardly transmitted through the opening of the elastic element, the opening of the circuit board and the keycap. 
     In an embodiment, the support part is made of a conductive material. 
     In an embodiment, the support part is doped with a conductive material. 
     In an embodiment, each of the first circuit pattern and the second circuit pattern has an L-shaped profile, an annular profile or a concave-convex staggered profile. 
     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.  1    is a schematic perspective view illustrating a control device according to a first embodiment of the present invention; 
         FIG.  2    is a schematic exploded view illustrating the control device as shown in  FIG.  1   ; 
         FIG.  3    is a schematic perspective view illustrating plural key structures of the control device as shown in  FIG.  2   ; 
         FIG.  4 A  schematically illustrates a first exemplary circuit structure of the circuit board in the key structure as shown in  FIG.  3   , in which the circuit patterns of the circuit board have inner and outer ring-shaped configurations; 
         FIG.  4 B  schematically illustrates a second exemplary circuit structure of the circuit board in the key structure as shown in  FIG.  3   , in which the circuit patterns of the circuit board have inner and outer concave-convex staggered configurations; 
         FIG.  4 C  schematically illustrates a third exemplary circuit structure of the circuit board in the key structure as shown in  FIG.  3   , in which the circuit patterns of the circuit board have L-shaped configurations; 
         FIG.  5    is a schematic cross-sectional view illustrating a key structure as shown in  FIG.  2   , in which the key structure is not pressed; 
         FIG.  6    is a schematic cross-sectional view illustrating a key structure as shown in  FIG.  2   , in which the key structure is pressed down; 
         FIG.  7    is a schematic perspective view illustrating plural key structures of a control device according to a second embodiment of the present invention; 
         FIG.  8    is a schematic exploded view illustrating portions of the key structures as shown in  FIG.  7   ; 
         FIG.  9    is a schematic exploded view illustrating the key structures as shown in  FIG.  7   ; 
         FIG.  10    is a schematic cross-sectional view illustrating the key structure as shown in  FIG.  7   , in which the key structure is not pressed; and 
         FIG.  11    is a schematic cross-sectional view illustrating the key structure as shown in  FIG.  7   , in which the key structure is pressed down. 
     
    
    
     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. In the following embodiments and drawings, the elements irrelevant to the concepts of the present invention are omitted and not shown. 
     A first embodiment of the present invention provides a key structure and a control device using the key structure. The control device is applied to a live streaming machine, a live production switcher, an ordering machine or a drawing device. 
       FIG.  1    is a schematic perspective view illustrating a control device according to a first embodiment of the present invention.  FIG.  2    is a schematic exploded view illustrating the control device as shown in  FIG.  1   .  FIG.  3    is a schematic perspective view illustrating plural key structures of the control device as shown in  FIG.  2   .  FIG.  4 A  schematically illustrates a first exemplary circuit structure of the circuit board in the key structure as shown in  FIG.  3   , in which the circuit patterns of the circuit board have inner and outer ring-shaped configurations.  FIG.  4 B  schematically illustrates a second exemplary circuit structure of the circuit board in the key structure as shown in  FIG.  3   , in which the circuit patterns of the circuit board have inner and outer concave-convex staggered configurations.  FIG.  4 C  schematically illustrates a third exemplary circuit structure of the circuit board in the key structure as shown in  FIG.  3   , in which the circuit patterns of the circuit board have inner and outer L-shaped configurations.  FIG.  5    is a schematic cross-sectional view illustrating a key structure as shown in  FIG.  2   , in which the key structure is not pressed.  FIG.  6    is a schematic cross-sectional view illustrating a key structure as shown in  FIG.  2   , in which the key structure is pressed down. 
     As shown in  FIGS.  1  to  6   , the control device  1  comprises a covering member  11 , an upper cover  12 , plural key structures  13 , a supporting element  14 , a display panel  15  and an outer casing  16 . 
     An accommodation space is defined by the covering member  11  and the outer casing  16  collaboratively. The upper cover  12 , the plural key structures  13 , the supporting element  14  and the display panel  15  are disposed within the accommodation space. Optionally, a processor, a signal processing device and a communication interface that support the key structures  13  and the display panel  15  are disposed within the control device  1 . 
     According to the predetermined control and setting of the user or the system, different images, information or pictures generated by the display panel  15  can be shown on individual key regions of the key structures  13 . Consequently, after a specified key structure  13  is selected and pressed down by the user, the control device  1  issues or executes a control signal corresponding to the image, the information or the picture. Moreover, the image, the information or the picture generated by the display panel  15  can be changed by the user. 
     In an embodiment, different images, information or pictures generated by the display panel  15  can be combined together in one or plural groups and shown on the plural key regions of the key structures  13 . Consequently, a larger image, information or picture can be collaboratively shown on the display panel  15  under the plural key structures  13 . 
     The number of the key structures  13  of the control device  1  may be determined according to the practical requirements or specifications. 
     As shown in  FIG.  2   , the covering member  11  comprises plural perforations  111 . The positions of the perforations  111  are aligned with the positions of the plural key structures  13 . In addition, the sizes of the perforations  111  match the sizes of the corresponding key structures  13 . Consequently, portions of the key structures  13  can be exposed outside the corresponding perforations  111  in order to be pressed or operated by the user. Similarly, as shown in  FIG.  2   , the upper cover  12  comprises plural perforations  121 . The positions of the perforations  121  are aligned with the positions of the plural key structures  13 . In addition, the sizes of the perforations  121  match the sizes of the corresponding key structures  13 . Consequently, portions of the key structures  13  can be exposed outside the corresponding perforations  121  in order to be pressed or operated by the user. 
     Please refer to  FIG.  2    again. The key structures  13  are located over the display panel  15 . The supporting element  14  is arranged between the key structures  13  and the display panel  15 . The supporting element  14  comprises a hollow portion  141 . The image, the information or the picture generated by the display panel  15  can be transmitted upwardly through the hollow portion  141 . 
     Please refer to  FIG.  3   . Each of the plural key structures  13  comprises a keycap  131 , an adhesive layer  132 , an adhesive layer  133 , an elastic element  134 , a conducting element  135  and a circuit board  136 . 
     The keycap  13  is made of a light-transmissible material. The keycap  13  comprises a press surface  1311  and a bottom surface  1312 . 
     The elastic element  134  has the elastic property. Due to the elastic property, the elastic element  134  can be returned to its original position. After the elastic element  134  is combined with the keycap  131 , the elastic element  134  provides an elastic force for moving upwardly and downwardly the keycap  131  in a reciprocating manner. 
     In an embodiment, the elastic element  134  comprises a support part  1341 , a lateral wall  1342 , a lower part  1343  and an opening  1344 . The lateral wall  1342  is arranged between the support part  1341  and the lower part  1343 . The support part  1341  and the lateral wall  1342  are arranged around the opening  1344 . The lower part  1343  is contacted with the circuit board  136 . The material and operation of the elastic element  134  are similar to the rubber dome of the conventional keyboard device. However, a middle region of the elastic element  134  comprises the opening  1344 . 
     The support part  1341  of the elastic element  134  comprises a top surface  13411  and a bottom surface  13412 . The top surface  13411  of the support part  1341  is upwardly connected with the bottom surface  1312  of the keycap  131  through the adhesive layer  132 . The adhesive layer  132  comprises an opening  1321 . The profile of the adhesive layer  132  matches the profile of the top surface  13411  of the support part  1341  of the elastic element  134 . 
     The conducting element  135  has an annular structure with a central hollow portion. The conducting element  135  is disposed on a bottom edge of the support part  1341  of the elastic element  134 . That is, the conducting element  135  is disposed on the bottom surface  13412  of the support part  1341 . The conducting element  135  is a metal sheet, a conductive rubber sheet, a carbon film, a conductive glue or a conductive foam. Moreover, the conducting element  135  can be formed on the bottom surface  13412  of the support part  1341  by a carbon printing process, a spraying process, a coating process or an injection process. 
     The lower part  1343  of the elastic element  134  is upwardly attached on the upper cover  12  through the adhesive layer  133 . Moreover, the lower part  1343  of the elastic element  134  is downwardly contacted with the circuit board  136 . 
     The lateral wall  1342  of the elastic element  134  has the elastic property. The lateral wall  1342  of the elastic element  134  is bendable or compressible. Consequently, the elastic element  134  can be subjected to deformation and returned to its original position. 
     The circuit board  136  is located over the display panel  15 . The circuit board  136  comprises a top surface  1361 , an opening  1362  and a circuit structure  1363 . The circuit structure  1363  is installed on the top surface  1361  of the circuit board  136 . Moreover, the circuit structure  1363  is arranged around the opening  1362 . The circuit structure  1363  at least comprises a first circuit pattern  1363 A and a second circuit pattern  1363 B. The first circuit pattern  1363 A and the second circuit pattern  1363 B are separated from each other by a gap. After the light beam generated by the display panel  15  is sequentially transmitted through the opening  1362  of the circuit board  136 , the opening  1344  of the elastic element  134  and the light-transmissible keycap  131 , the corresponding image, information or picture is visible by the user for facilitating the user&#39;s selection or operation. 
     The arrangements and the profiles of the first circuit pattern  1363 A and the second circuit pattern  1363 B may be determined according to the application requirements and the use conditions. For example, three examples of the circuit structure are shown in  FIGS.  4 A,  4 B and  4 C . As shown in  FIG.  4 A , the circuit patterns  1363 A 1  and  1363 B 1  have inner and outer ring-shaped configurations. For example, the first circuit pattern  1363 A is arranged around the second circuit pattern  1363 B. As shown in  FIG.  4 B , the circuit patterns  1363 A 2  and  1363 B 2  have inner and outer concave-convex staggered configurations. As shown in  FIG.  4 C , the circuit patterns  1363 A 3  and  1363 B 3  have L-shaped configurations. The arrangements and the profiles of the first circuit pattern  1363 A and the second circuit pattern  1363 B are not restricted as long as they are separated and not electrically with each other. In  FIGS.  3 ,  5  and  6   , the circuit patterns  1363 A 1  and  1363 B 1  in ring-shaped configurations are taken as an example. Moreover, the first circuit pattern  1363 A and the second circuit pattern  1363 B are extended along the circuit board  136  and collected to a connector or other signal processing component. 
     Please refer to  FIGS.  5  and  6   . When the keycap  131  is pressed down by the user, the keycap  131  is moved downwardly to push the support part  1341  of the elastic element  134 . After the support part  1341  is moved downwardly for a specified travel distance, the conducting element  135  on the bottom edge of the support part  1341  is contacted with the first circuit pattern  1363 A 1  and the second circuit pattern  1363 B 1  of the circuit board  136  (see  FIG.  6   ). Consequently, the first circuit pattern  1363 A 1  and the second circuit pattern  1363 B 1  are electrically connected with each other. Under this circumstance, the circuit board  136  generates a pressing signal corresponding to the pressed keycap  131 . 
     When the keycap  131  is no longer pressed by the user, the keycap  131  is returned to its original position as shown in  FIG.  5    in response to the upward restoring elastic force of the elastic element  134 . Meanwhile, the electric connection between the first circuit pattern  1363 A 1  and the second circuit pattern  1363 B 1  through the conducting element  135  is interrupted. That is, the first circuit pattern  1363 A 1  and the second circuit pattern  1363 B 1  are not electrically connected with each other. 
     It is noted that numerous modifications may be made while retaining the teachings of the present invention. For example, in some variant examples, the support part  1341  of the elastic element  134  is made of a conductive material, or a conductive material (e.g., particulate metallic material) is doped or added into the support part  1341 . Consequently, the support part  1341  has the conducting function. That is, the support part  1341  is electrically conductive. In these variant examples, it is not necessary to install the conducting element  135  on the bottom edge of the support part  1341 . 
     When the keycap  131  is pressed down by the user, the keycap  131  is moved downwardly to push the support part  1341  of the elastic element  134 . After the support part  1341  is moved downwardly for a specified travel distance, the support part  1341  is directly contacted with the first circuit pattern  1363 A and the second circuit pattern  1363 B of the circuit board  136 . Consequently, the first circuit pattern  1363 A and the second circuit pattern  1363 B are electrically connected with each other. Under this circumstance, the circuit board  136  generates a pressing signal corresponding to the pressed keycap  131 . 
     When the keycap  131  is no longer pressed by the user, the keycap  131  is returned to its original position in response to the upward restoring elastic force of the elastic element  134 . Meanwhile, the electric connection between the first circuit pattern  1363 A and the second circuit pattern  1363 B through the conducting element  135  is interrupted. That is, the first circuit pattern  1363 A and the second circuit pattern  1363 B are not electrically connected with each other. 
     In the above embodiments of the key structure, the conducting element  135  or the support part  1341  is contacted with and electrically connected with the first circuit pattern  1363 A and the second circuit pattern  1363 B of the circuit board  136  after the keycap  131  is pressed down. In some other embodiments, the triggering method of the key structure is distinguished. That is, when the keycap is not pressed down, the conducting element or the support part is contacted with and electrically connected with the first circuit pattern and the second circuit pattern of the circuit board. Meanwhile, the key structure or the control device using the key structure does not issue the pressing signal. After the keycap is pressed down, the conducting element or the support part is detached from the first circuit pattern and the second circuit pattern of the circuit board. After a signal processing process is performed, the key structure or the control device using the key structure issues the pressing signal. 
     A second embodiment of the present invention provides a key structure and a control device using the key structure. In comparison with the first embodiment, the triggering method of the key structure in the second embodiment is distinguished. The other components of the control device of this embodiment are similar to those of the first embodiment, and not redundantly described herein. 
       FIG.  7    is a schematic perspective view illustrating plural key structures of a control device according to a second embodiment of the present invention.  FIG.  8    is a schematic exploded view illustrating portions of the key structures as shown in  FIG.  7   .  FIG.  9    is a schematic exploded view illustrating the key structures as shown in  FIG.  7   .  FIG.  10    is a schematic cross-sectional view illustrating the key structure as shown in  FIG.  7   , in which the key structure is not pressed.  FIG.  11    is a schematic cross-sectional view illustrating the key structure as shown in  FIG.  7   , in which the key structure is pressed down. 
     In  FIGS.  7  to  11   , the key structures  23  are shown. Each key structure  23  is located over a display panel  15 . 
     Each of the plural key structures  23  at least comprises a keycap  231 , an elastic element  234 , a conducting element  235  and a circuit board  236 . 
     The keycap  231  is made of a light-transmissible material. The keycap  231  comprises a press surface  2311 , a wall part  2312  and a pedestal  2313 . 
     The image, the information or the picture generated by the display panel  15  is transmitted upwardly through the keycap  231  and thus visible by the user. Moreover, the image, the information or the picture defined by the light beams from the display panel  15  can be changed by the user. 
     The pedestal  2313  is horizontally and externally protruded from the wall part  2312 . Moreover, the pedestal  2313  has a top surface  23131  and a bottom surface  23132 . 
     The elastic element  234  has the elastic property. Due to the elastic property, the elastic element  234  can be returned to its original position. After the elastic element  234  is combined with the pedestal  2313  of the keycap  231 , the elastic element  234  provides an elastic force for moving upwardly and downwardly the keycap  231  in a reciprocating manner. 
     In an embodiment, the elastic element  234  comprises a support part  2341 , a lateral wall  2342 , a lower part  2343  and an opening  2344 . The lateral wall  2342  is arranged between the support part  2341  and the lower part  2343 . The lateral wall  2342  of the elastic element  234  has the elastic property. The lateral wall  2342  of the elastic element  234  is bendable or compressible. Consequently, the elastic element  234  can be subjected to deformation and returned to its original position. The support part  2341  and the lateral wall  2342  are arranged around the opening  2344 . Moreover, the lower part  2343  of the elastic element  234  is downwardly contacted with the display panel  15 , or the lower part  2343  of the elastic element  234  is contacted with a supporting element (not shown) between the elastic element  234  and the display panel  15 . 
     The support part  2341  of the elastic element  234  comprises a top surface  23411  and a fixing recess  23412 . The fixing recess  23412  has a concave structure. The size of the fixing recess  23412  matches the outer periphery of the pedestal  2313  of the keycap  231 . Consequently, the pedestal  2313  of the keycap  231  can be received within the fixing recess  23412 . Optionally, the bottom surface  23132  of the pedestal  2313  of the keycap  231  is attached on the inner surface of the fixing recess  23412  by an adhesive layer or any other appropriate fixing means. 
     The conducting element  235  has an annular structure with a central hollow portion. The conducting element  235  is sheathed around or arranged around the pedestal  2313  of the keycap  231 . Moreover, the conducting element  235  is attached on the top surface  23131  of the pedestal  2313  of the keycap  231  and/or the top surface  23411  of the support part  2341  of the elastic element  234 . As shown in  FIGS.  10  and  11   , the conducting element  235  is attached on the top surface  23131  of the pedestal  2313  of the keycap  231  and attached on the top surface  23411  of the support part  2341  of the elastic element  234 . It is noted that the position of the conducting element  235  is not restricted. The conducting element  235  is a metal sheet, a conductive rubber sheet, a carbon film, a conductive glue or a conductive foam. Moreover, the conducting element  235  can be formed on the pedestal  2313  or the support part  2341  by a carbon printing process, a spraying process, a coating process or an injection process. 
     The circuit board  236  is located over the elastic element  234 . The circuit board  236  comprises a top surface  2361 , an opening  2362 , a bottom surface  2363  and a circuit structure  2364 . The circuit structure  2364  is installed on the bottom surface  2363  of the circuit board  236 . Moreover, the circuit structure  2364  is arranged around the opening  2362 . The circuit structure  2364  at least comprises a first circuit pattern  2364 A and a second circuit pattern  2364 B. The first circuit pattern  2364 A and the second circuit pattern  2364 B are separated from each other by a gap. The arrangements and the profiles of the first circuit pattern  2364 A and the second circuit pattern  2364 B may be determined according to the application requirements and the use conditions. The profiles of the circuit patterns are similar to those of the first embodiment. For example, the first circuit pattern  2364 A and the second circuit pattern  2364 B have ring-shaped profiles, concave-convex staggered profiles or L-shaped profiles. In  FIGS.  8 ,  10  and  11   , the circuit patterns  2364 A 1  and  2364 B 1  in ring-shaped configurations are taken as an example. Moreover, the circuit pattern  2364 A 1  is arranged around the circuit pattern  2364 B 1 . 
     After the light beam generated by the display panel  15  is transmitted through the opening  2344  of the elastic element  234 , the opening  2362  of the circuit board  236  and the light-transmissible keycap  231  sequentially, the corresponding image, information or picture is visible by the user for facilitating the user&#39;s selection or operation. 
     Please refer to  FIGS.  10  and  11   . When the keycap  231  is not pressed down by the user, the conducting element  235  is upwardly contacted with the first circuit pattern  2364 A 1  and the second circuit pattern  2364 B 1  on the bottom surface  2363  of the circuit board  236 . Under this circumstance, the first circuit pattern  2364 A 1  and the second circuit pattern  2364 B 1  are conducted or electrically connected with each other. Meanwhile, the key structure  23  or the control device using the key structure  23  does not issue a pressing signal after a signal processing process is performed. 
     When the keycap  231  is pressed down by the user, the conducting element  235  is moved downwardly. Consequently, as shown in  FIG.  11   , the conducting element  235  is detached from the first circuit pattern  2364 A 1  and the second circuit pattern  2364 B 1 . Under this circumstance, the first circuit pattern  2364 A 1  and the second circuit pattern  2364 B 1  are not conducted or electrically connected with each other. After a signal processing process is performed, the key structure  23  or the control device using the key structure  23  issues the pressing signal. 
     When the keycap  231  is no longer pressed by the user, the keycap  231  is returned to its original position in response to the upward restoring elastic force of the elastic element  234  (see  FIG.  10   ). Meanwhile, the electric connection between the first circuit pattern  2364 A 1  and the second circuit pattern  2364 B 1  through the conducting element  235  is established again. 
     It is noted that numerous modifications may be made while retaining the teachings of the present invention. For example, in some variant examples, the support part  2341  of the elastic element  234  is made of a conductive material, or a conductive material (e.g., particulate metallic material) is doped or added into the support part  2341 . Consequently, the support part  2341  has the conducting function. In these variant examples, it is not necessary to install the conducting element  235  on the top surface of the support part  2341 . 
     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.