Patent Publication Number: US-2016233861-A1

Title: Keyboard device

Description:
FIELD OF THE INVENTION 
     The present invention relates to a keyboard device, and more particularly to a keyboard device with a restoring element, wherein the restoring element is subjected to deformation when receiving electricity. 
     BACKGROUND OF THE INVENTION 
     As known, a keyboard device can provide an intuitional feedback-imparting interface for allowing the user to input signals to an electronic device in a simple manner. Even if most electronic devices are equipped with touch screens and virtual keyboards are shown on the touch screens for allowing users to input signals, physical keyboard are still frequently used by most users because the hand feel of touching the touch screen is lower than the tactile feedback of pressing the physical keyboard and the possibility of erroneously touching other keys of the touch screen is very high. 
       FIG. 1  is a schematic view illustrating a conventional keyboard device. As shown in  FIG. 1 , the conventional keyboard device  10  comprises plural keys  11 , a circuit board  12  and a base plate  13 . Each of the plural keys  11  comprises a keycap  111 , a scissors member  112  and a rubbery elastomer  113 . The keys  11  are disposed on the circuit board  12 . The circuit board  12  is disposed on the base plate  13 . In particular, the scissors member  112  is arranged between the keycap  111  and the rubbery elastomer  113  for connecting the keycap  111  and the base plate  13 . The rubbery elastomer  113  is disposed on the circuit board  12  and located under the scissors member  112  for returning the keycap  111  to the original position. When the key  11  is depressed, the keycap  111  is moved downwardly to press the rubbery elastomer  113  so as to result in deformation of the rubbery elastomer  113 . Moreover, the circuit board  12  is pressed by the rubbery elastomer  113  so as to generate a key signal. When the key  11  is no longer depressed, the rubbery elastomer  113  is restored to the original shape. Consequently, the keycap  111  is moved upwardly in the direction away from the base plate  13 . 
     As mentioned above, the rubbery elastomer  113  of the keyboard device  10  can provide the hand feed of pressing the key  11  to the user. Moreover, when the key  11  is no longer depressed by the user, the rubbery elastomer  113  can allow the keycap  111  of the key  11  to be returned to the original position. However, since the rubbery elastomer  113  has certain height and volume, the arrangement of the rubbery elastomer  113  may increase the overall height of the keyboard device  10 . Under this circumstance, it is difficult for the user to carry the keyboard device  10 . 
     In other words, it is an important issue to provide a keyboard device with slimness and hand feel. Therefore, there is a need of providing an improved keyboard device in order to overcome the above drawbacks. 
     SUMMARY OF THE INVENTION 
     An object of the present invention provides a slim-type keyboard device. 
     In accordance with an aspect of the present invention, there is provided a keyboard device. The keyboard device includes a base plate, a circuit board and plural keys. The circuit board is disposed on the base plate. The plural keys are disposed on the circuit board. Each of the plural keys includes a keycap, a scissors member, a restoring element and a sensor. The scissors member is arranged between the keycap and the base plate and connected with the keycap and the base plate. The restoring element is arranged between the keycap and the base plate and electrically connected with the circuit board to receive electricity from the circuit board. When the electricity is received by the restoring element, the restoring element is subjected to deformation to move the keycap away from the base plate. The sensor is disposed under the restoring element and electrically connected with the circuit board. When the sensor is triggered, a key signal is generated. When the keycap is depressed and close to the base plate, the restoring element is pressed by the keycap to trigger the sensor to generate the key signal. When the keycap is no longer depressed, the keycap is driven by the restoring element so as to be moved away from the base plate. 
     In an embodiment, the sensor is disposed on the circuit board, and the restoring element is located over the sensor. 
     In an embodiment, the circuit board includes plural openings, wherein each restoring element and the corresponding sensor are disposed within the corresponding opening. 
     In an embodiment, the restoring element is made of electroactive polymer (EAP). 
     In an embodiment, the keycap further includes a protrusion. The protrusion is disposed on a bottom surface of the keycap and contacted with the restoring element. When the keycap is depressed, the restoring element is pressed by the protrusion of the keycap. 
     In an embodiment, when the electricity is not received by the restoring element, the restoring element has a flat rectangular shape, wherein when the electricity is received by the restoring element, the restoring element has a cambered rectangular shape. 
     In an embodiment, each keycap includes plural first fixing parts, and the base plate comprises plural second fixing parts. The scissors member is fixed on the base plate through the plural first fixing parts and the plural second fixing parts. 
     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 view illustrating a conventional keyboard device; 
         FIG. 2  is a schematic perspective view illustrating a keyboard device according to a first embodiment of the present invention; 
         FIG. 3  is a schematic exploded view illustrating a key according to a first embodiment of the present invention; 
         FIG. 4  schematically illustrates the key according to the first embodiment of the present invention, in which no electricity is received by the restoring element; 
         FIG. 5  schematically illustrates the key according to the first embodiment of the present invention, in which the electricity is received by the restoring element; 
         FIG. 6  schematically illustrates the key according to the first embodiment of the present invention, in which the key is depressed; 
         FIG. 7  is a schematic exploded view illustrating a key according to a second embodiment of the present invention; 
         FIG. 8  schematically illustrates the key according to the second embodiment of the present invention, in which no electricity is received by the restoring element; and 
         FIG. 9  schematically illustrates the key according to the second embodiment of the present invention, in which the electricity is received by the restoring element. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Please refer to  FIGS. 2 and 3 .  FIG. 2  is a schematic perspective view illustrating a keyboard device according to a first embodiment of the present invention.  FIG. 3  is a schematic exploded view illustrating a key according to a first embodiment of the present invention. As shown in  FIGS. 2 and 3 , the keyboard device  20  comprises plural keys  21 , a circuit board  22  and a base plate  23 . The circuit board  22  comprises a first electrical contact  221 , a second electrical contact  222 , a third electrical contact  223  and a fourth electrical contact  224 . The plural keys  21  are disposed on the circuit board  22 . When one of the plural keys  21  is depressed by the user, a corresponding key signal is generated. Moreover, the plural keys  21  and the circuit board  22  are all disposed on the base plate  23 . The base plate  23  is a plate made of a metallic material, a plastic material or any other appropriate material. The base plate  23  is used for supporting the plural keys  21  and the circuit board  22 . An example of the keyboard device  20  includes but is not limited to a wired keyboard device or a wireless keyboard device. 
     Please refer to  FIG. 3  again. Each key  21  comprises a keycap  211 , a scissors member  212 , a restoring element  213  and a sensor  214 . The keycap  211  comprises plural first fixing parts  211   a ,  211   b ,  211   c  and  211   d  and a protrusion  211   e . The base plate  23  comprises plural second fixing parts  23   a ,  23   b ,  23   c  and  23   d . The plural first fixing parts  211   a ,  211   b ,  211   c  and  211   d  are disposed on a bottom surface of the keycap  211 . The plural second fixing parts  23   a ,  23   b ,  23   c  and  23   d  are disposed on a top surface of the base plate  23 . In this embodiment, the keycap  211  is made of a plastic material. Preferably but not exclusively, the plural first fixing parts  211   a ,  211   b ,  211   c  and  211   d  and the protrusion  211   e  are integrally formed on the bottom surface of the keycap  211  by an ejection molding process. 
     The scissors member  212  is arranged between the keycap  211  and the base plate  23  for connecting the keycap  211  and the base plate  23 . That is, the keycap  211  is fixed on the base plate  23  through the scissors member  212 . For example, the top ends and the bottom ends of the scissors member  212  have plural locking parts. The locking parts at the top ends of the scissors member  212  are connected with the plural first fixing parts  211   a ,  211   b ,  211   c  and  211   d  of the keycap  211 , and the locking parts at the bottom ends of the scissors member  212  are connected with the plural second fixing parts  23   a ,  23   b ,  23   c  and  23   d  of the base plate  23 . When the plural locking parts of the scissors member  212  are connected with the plural first fixing parts  211   a ,  211   b ,  211   c  and  211   d  and the plural second fixing parts  23   a ,  23   b ,  23   c  and  23   d , the scissors member  212  is fixed on the base plate  23  and the keycap  211  is fixed on the scissors member  212 . Consequently, the keycap  211  is fixed on the base plate  23 . The structures of the scissors member  212  of the present invention are substantially identical to those of the conventional scissors member, and are not redundantly described herein. 
     The restoring element  213  is arranged between the keycap  211  and the base plate  23  for returning the keycap  211  to its original position. In particular, the restoring element  213  is disposed on the circuit board  22 , and electrically connected with the first electrical contact  221  and the second electrical contact  222  of the circuit board  22  so as to acquire electricity from the circuit board  22 . In this embodiment, the restoring element  213  is made of electroactive polymer (EAP). In case that no electricity is received by the restoring element  213 , the restoring element  213  has a flat rectangular shape. Whereas, in case that the electricity is received by the restoring element  213 , the restoring element  213  has a cambered rectangular shape. Consequently, when the electricity is received by the restoring element  213 , the keycap  211  is moved away from the base plate  23  in response to the deformation of the restoring element  213 . 
     The sensor  214  is disposed under the restoring element  213 . Moreover, the sensor  214  is disposed on the circuit board  22 , and electrically connected with the third electrical contact  223  and the fourth electrical contact  224  of the circuit board  22 . When the electricity from the circuit board  22  is received by the sensor  214 , the sensor  214  is enabled to sense whether the keycap  211  is depressed. When the keycap  211  is depressed, the sensor  214  generates the key signal. In addition, the key signal is transmitted through the circuit board  22  to the electronic device that is controlled by the keyboard device  20 . For example, the electronic device controlled by the keyboard device  20  includes a desktop computer, a notebook computer, a tablet computer or a smart phone. 
     The operations of the key  21  will be illustrated with reference to  FIGS. 4, 5 and 6 .  FIG. 4  schematically illustrates the key according to the first embodiment of the present invention, in which no electricity is received by the restoring element.  FIG. 5  schematically illustrates the key according to the first embodiment of the present invention, in which the electricity is received by the restoring element.  FIG. 6  schematically illustrates the key according to the first embodiment of the present invention, in which the key is depressed. As shown in  FIG. 4 , the keyboard device  20  is not electrically connected with the electronic device or a power switch of the keyboard device  20  is not turned on. Since no electricity is received by the restoring element  213 , the restoring element  213  has the flat rectangular shape. Meanwhile, the distance between the keycap  211  and the bottom and the base plate  23  is equal to a first height H 1 . 
     When the keyboard device  20  is electrically connected with the electronic device (e.g., a computer) or the power switch of the keyboard device  20  is turned on, the electricity from the circuit board  22  is transmitted to the power consumption components of the keyboard device  20 . For example, the power consumption components include the restoring element  213  and the sensor  214 . As shown in  FIG. 5 , the restoring element  213  receives the electricity. Consequently, the restoring element  213  is subjected to deformation, and the restoring element  213  is switched from the flat rectangular shape to the cambered rectangular shape. Under this circumstance, the scissors member  212  is in an open-scissors state. Meanwhile, the distance between the keycap  211  and the bottom and the base plate  23  is increased to a second height H 2 . 
     Then, as shown in  FIG. 6 , an external force F is applied to the keycap  211  of the key  21 . In response to the external force F, the keycap  211  is moved downwardly. As the keycap  211  is moved downwardly, the protrusion  211   e  is contacted with the restoring element  213  to press the restoring element  213 . Consequently, the sensor  214  is triggered to generate the key signal. Preferably but not exclusively, the sensor  214  is a membrane switch circuit, a capacitive sensor or any other appropriate sensor. For example, if the sensor  214  is the membrane switch circuit, the depressed restoring element  213  is contacted with the sensor  214  to push the sensor  214 . Consequently, the circuitry of the sensor  214  is electrically conducted to generate the key signal. If the sensor  214  is the capacitive sensor and the depressed restoring element  213  is close to the sensor  214 , the sensor  214  senses the change of the capacitance value. According to the change of the capacitance value, the key signal is generated. 
     When the keycap  211  is no longer depressed by the user, the shape of the restoring element  213  is restored to the cambered rectangular shape (see  FIG. 5 ) because the electricity is still received by the restoring element  213 . By means of the restoring element  213 , the keycap  211  is returned to the original position, so that the distance between the keycap  211  and the bottom and the base plate  23  is increased to the second height H 2  again. Consequently, the keycap  211  is moved away from the base plate  23 . Similarly, when the external force F is applied to the keycap  211  of the key  21  again, the keycap  211  is moved downwardly again (see  FIG. 6 ). Consequently, the sensor  214  is triggered to generate the key signal. 
     The present invention further provides a key according to a second embodiment of the present invention.  FIG. 7  is a schematic exploded view illustrating a key according to a second embodiment of the present invention. As shown in  FIG. 7 , the keyboard device  30  comprises plural keys  31 , a circuit board  32  and a base plate  33 . The circuit board  32  comprises a first electrical contact  321 , a second electrical contact  322 , a third electrical contact  323  and a fourth electrical contact  324 . The plural keys  31  are disposed on the circuit board  32 . When one of the plural keys  31  is depressed by the user, a corresponding key signal is generated. Moreover, the plural keys  31  and the circuit board  32  are all disposed on the base plate  33 . Each key  31  comprises a keycap  311 , a scissors member  312 , a restoring element  313  and a sensor  314 . Moreover, a protrusion  311   a  is disposed on a bottom surface of the keycap  311 . 
     The scissors member  312  is arranged between the keycap  311  and the base plate  33  for connecting the keycap  311  and the base plate  33 . The way of fixing the keycap  311  on the base plate  33  through the scissors member  312  is similar to that of the first embodiment as shown in  FIG. 3 , and is not redundantly described herein. Moreover, the restoring element  313  is arranged between the keycap  311  and the base plate  33 , and the sensor  314  is disposed under the restoring element  313 . The restoring element  313  is used for returning the keycap  311  to its original position. The sensor  314  is used for generating the key signal. 
     The restoring element  313  and the sensor  314  are electrically connected with the circuit board  32 . In this embodiment, the restoring element  313  comprises a first coupling part  313   a  and a second coupling part  313   b . The first coupling part  313   a  and the second coupling part  313   b  of the restoring element  313  are electrically connected with the first electrical contact  321  and the second electrical contact  322  of the circuit board  32 , respectively. Consequently, the restoring element  313  can acquire electricity from the circuit board  32 . The sensor  314  comprises a third coupling part  314   a  and a fourth coupling part  314   b . The third coupling part  314   a  and the fourth coupling part  314   b  of the sensor  314  are electrically connected with the third electrical contact  323  and the fourth electrical contact  324  of the circuit board  32 , respectively. Consequently, the sensor  314  can acquire electricity from the circuit board  32 . Through the circuit board  32 , the generated key signal is transmitted to the electronic device that is controlled by the keyboard device  30 . 
     In this embodiment, the restoring element  313  is made of electroactive polymer (EAP). In case that no electricity is received by the restoring element  313 , the restoring element  213  has a flat rectangular shape. Whereas, in case that the electricity is received by the restoring element  313 , the restoring element  313  is subjected to deformation, and the restoring element  313  is switched from the flat rectangular shape to a cambered rectangular shape. Consequently, when the electricity is received by the restoring element  313 , the keycap  311  is moved away from the base plate  33  in response to the deformation of the restoring element  313 . 
     In comparison with the keyboard device  20  of  FIG. 3 , the circuit board  32  of the keyboard device  30  of this embodiment has plural openings  325 , and both of the restoring element  313  and the sensor  314  are disposed within the corresponding opening  325  of the circuit board  32 . The other components of the keyboard device  30  of this embodiment are substantially identical to those of the keyboard device  20  of the first embodiment, and are not redundantly described herein. Since both of the restoring element  313  and the sensor  314  are disposed within the corresponding opening  325  of the circuit board  32 , the height between the keycap  311  and the base plate  33  is further reduced. Consequently, the slimness efficacy of the keyboard device  30  is enhanced. 
     Please refer to  FIGS. 8 and 9 .  FIG. 8  schematically illustrates the key according to the second embodiment of the present invention, in which no electricity is received by the restoring element.  FIG. 9  schematically illustrates the key according to the second embodiment of the present invention, in which the electricity is received by the restoring element. As shown in  FIG. 8 , the circuit board  32  is disposed on the base plate  33 , and the restoring element  313  and the sensor  314  are disposed within the opening  325  of the circuit board  32 . As shown in  FIG. 9 , the restoring element  313  receives the electricity from the circuit board  32 . Since the electricity is received by the restoring element  313 , the restoring element  313  is subjected to deformation, and the restoring element  313  is switched from the flat rectangular shape to the cambered rectangular shape. Under this circumstance, the scissors member  312  is in an open-scissors state. Meanwhile, the distance between the keycap  311  and the bottom and the base plate  33  is increased. In case that the keycap  311  of the key  31  is depressed by the user, the keycap  311  is moved downwardly. As the keycap  311  is moved downwardly, the protrusion  311   a  is contacted with the restoring element  313  to press the restoring element  313 . Consequently, the sensor  314  is triggered to generate a key signal. 
     From the above descriptions, the present invention provides the keyboard device. When the electricity is received by the restoring element, the restoring element is subjected to deformation to move the keycap away from the base plate. Consequently, the keycap can be returned to its original position. In comparison with the conventional keyboard device using the rubbery elastomer as the restoring element, the height of the restoring element of the keyboard device is smaller than the height of the rubbery elastomer. Consequently, the overall height of the keyboard device of the present invention is reduced. Moreover, since the restoring element of the present invention results in the deformation when receiving the electricity, the restoring element has the restoring function. In case that the keyboard device of the present invention is not electrically connected with the electronic device or the power switch of the keyboard device is not turned on, no electricity is received by the restoring element, so that the restoring element has the flat rectangular shape. Consequently, the overall height of the keyboard device of the present invention is further reduced. That is, since the keyboard device of the present invention is slimmer and lighter, the keyboard device can be carried more easily. 
     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 such modifications and similar structures.