Patent Publication Number: US-9418800-B2

Title: Slim keypad structure and electronic device using the same

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a divisional application of U.S. application Ser. No. 13/295,173, filed on Nov. 14, 2011 and entitled “SLIM KEYPAD STRUCTURE AND ELECTRONIC DEVICE USING THE SAME”, the entire contents of which are hereby incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The instant disclosure is related to a slim keypad structure and electronic devices utilizing the same. In particular, the instant disclosure relates to a slim keypad structure particularly suitable for implementation in modern low-profile electronics, and an electronic device incorporating the slim keypad structure. 
     2. Description of Related Art 
     Speedy development of portable smart electronics, such as mobile phone, PDA, and tablet PC, constantly pushes the demand for devices having lower physical profile. With the improvement of touch-screen control interface, more and more electronic devices abandon the structural keypad in favor of the touch-screen input solution. However, the touch-screen operating interface cannot provide the affirmative tactile feedback of a structural keypad. 
     Obviously, the key structure needs further refinement to improve its compatibility and adaptability with the development trend of slim and light electronic device. The key structure is required be slim, structurally simple, and easy to assemble, so that it can match with the development trend of modern electronic devices. 
     Moreover, having limited available space, modern portable devices are often equipped with multi-functional software configurable keypads that have fewer keys than that of a conventional keyboard. Such keypads often have multiple alphabet/symbols printed the top surface of each key which in turn makes key identification confusing and difficult. 
     Therefore, it is desirable to propose a novel slim keyswitch to overcome the above-mentioned problems. 
     SUMMARY OF THE INVENTION 
     The instant disclosure provides a slim keypad structure that is structurally thin, simple, and easy to assemble, and is capable of providing affirmative tactile feedback. 
     The instant disclosure further provides a slim keypad structure, in which the same keypad structure can show different symbols to enhance the flexibility of operation. 
     In order to achieve the above objectives, the instant disclosure is to provide a slim keypad structure, which includes a supporting plate, at least one key cap, at least one dome, and a light-penetrable circuit board. The supporting plate has at least one frame portion, and each frame portion is formed with a light-pervious opening at a central portion thereof. The key cap is disposed on a top surface of the frame portion correspondingly. The circuit board has at least one conducted circuit formed under the dome correspondingly, wherein the supporting plate is arranged above the circuit board with an interval. The dome is disposed under the frame portion correspondingly. 
     According to one embodiment of the instant disclosure, the key cap is board-shaped and is light-penetrable. 
     According to one embodiment of the instant disclosure, further includes a displaying element to shown at least one symbol. The symbol is shown on a top surface of the key cap through the circuit board and the light-pervious opening of the supporting plate. 
     Moreover, the instant disclosure provides an electronic device with slim keypad structure. 
     In order to achieve the above objectives, one embodiment according to the instant disclosure provides an electronic device with slim keypad structure. The slim keypad structure includes a supporting plate, at least one key cap, at least one dome, and a light-penetrable circuit board. The supporting plate at least one frame portion, and each frame portion is formed with a light-pervious opening at a central portion thereof. The key cap is disposed on a top surface of the frame portion correspondingly. The circuit board has at least one conducted circuit correspondingly formed under the dome, wherein the supporting plate is arranged above the circuit board with an interval. The dome is disposed under the frame portion correspondingly. 
     Thus, the instant disclosure has advantages as followed. The slim design reduces the thickness of the electronic device effectively. The same keypad structure can show different symbols, so that the operation is more flexible 
     For further understanding of the instant disclosure, reference is made to the following detailed description illustrating the embodiments and examples of the instant disclosure. The description is for illustrative purpose only and is not intended to limit the scope of the claim. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective exploded view of slim keypad structure according to the instant disclosure; 
         FIG. 2  is a perspective assembled view of slim keypad structure according to the instant disclosure; 
         FIG. 3  is a side view of slim keypad structure according to the instant disclosure; 
         FIG. 3A  is a perspective exploded view of slim keypad structure of second embodiment according to the instant disclosure; 
         FIG. 3B  is a perspective exploded view of slim keypad structure of third embodiment according to the instant disclosure; 
         FIG. 3C  is a side view of uplifted supporting plate of second embodiment according to the instant disclosure; 
         FIG. 3D  is a side view of uplifted supporting plate of third embodiment according to the instant disclosure; 
         FIG. 4  is a perspective cross-sectional view of slim keypad structure according to the instant disclosure; and 
         FIG. 5  is a perspective view of an electronic device having the slime keypad structure according to the instant disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In order to better understand the objective, structure, characteristics, and effects of the instant disclosure, a description relating thereto will be made with reference to preferred embodiments thereof and the accompanying drawings. 
     Reference is made to  FIGS. 1 and 2 , which are a perspective exploded view and a perspective assembled view of slim keypad structure according to the instant disclosure. A slim keypad structure  100  according to the instant disclosure includes a supporting plate  10 , a plurality of key caps  20  disposed on the supporting plate  10 , a plurality of domes  30  disposed under the supporting plate  10  and a circuit board  40  formed with conductive circuits (not shown). The domes  30  are disposed on the circuit board  40 . The slim keypad structure  100  of instant disclosure can be independently applied as one keypad structure or multiple keypad structure in a multi-rows configuration. In this embodiment, two rows of keypad structure are illustrated as example, namely, the key caps  20  are arranged in two rows. The details are introduced as follows. 
     The supporting plate  10  is disposed above the circuit board  40  with an interval, and is used to elastically support the key cap  20 . Thus, elasticity is provided to the key cap  20 , and the key cap  20  can be restored to the original position after being pressed. The supporting plate  10  has a plurality of frame portions  12 . Each of the frame portions  12  is formed with a light-pervious opening  120  at a center thereof. In this embodiment the frame portion  12  is rectangle-shaped, but it is not limited thereto. For example, it can be shaped in polygon or semicircle, which just forms a frame structure to elastically support key cap  20 . The shape of the light-pervious opening  120  is not limited in rectangle as shown in this embodiment, which is allowed to light permit through and can reduce the weight of the supporting plate  10 . 
     When the slim keypad structure of the instant disclosure is applied in one single keypad structure, which needs only one frame portion  12 . In other words, the number of the frame portion  12  could be at least one. The instant disclosure makes the keypad structure slim though the supporting plate  10 . The supporting plate  10  can be a metal board by punched or made of plastic. 
     According to this embodiment, to uplift the supporting plate  10  above the circuit board  40 , the supporting plate  10  has an uplifted portion  14  protruded downward from an edge of the frame portion  12 . The uplifted portion  14  is downward arc-shaped and parallel to one side of the frame portion  12 , as shown in  FIG. 3 . In side view, the uplifted portion  14  is shaped in half-cylinder with an arc-shaped groove. The uplifted portion  14  is used to uplift the frame portion  12  with a predetermined height, so that the frame portion  12  is suspended in midair and provides the key cap  20  a recovery force after being pressed. However, the way to uplift the supporting plate  10  of this instant disclosure is not limited to this embodiment. 
     The figures of this embodiment are illustrated with a keypad structure arranged in a multi-row configuration, i.e., the supporting plate  10  has a plurality of frame portions  12  which are arranged in two rows. Each row of the frame portions  12  has an uplifted portion  14  and  14   a  arranged in a straight line at the front edge thereof. Each frame portion  12  has an outer edge formed a substantial U-shaped hollowed slot  101 . The straight-shaped uplifted portion  14  connects many frame portions  12  and is arranged in rows. The hollowed slot  101  makes each of the frame portions  12  been able to press independently. The size of the key cap  20  is slightly larger than that of the frame portion  12 , and the edge of the key cap  20  is located in the hollowed slot  101 . 
     Referring to  FIGS. 1 and 3 , wherein  FIG. 3  is side view of the slim keypad structure. In this embodiment, the frame portion  12  further includes a downward bump  122  above the dome  30 , and is formed on the frame portion  12  where far away the uplifted portion  14   a . The bump  122  is against the dome  30  correspondingly, and can reduce the pressing stroke of the frame portion  12  and avoid affecting the neighbor frame portion  12 , such as being raised, when the key cap  20  is pressed. 
     Referring to  FIGS. 1 and 3 , the key caps  20  are correspondingly disposed on a top surface of the frame portions  12 . The key cap  20  may be slab-shaped and made of transparent material, such as plastic, making it pervious to light. Each of the key caps  20  has a positioning protrusion  22  protruded from a bottom surface thereof. The positioning protrusion  22  is correspondingly shaped to wedge in the light-pervious opening  120  in such a way that allows the key cap  20  to be fixed onto the frame portion  12 . In this embodiment, the thickness of the positioning protrusion  22  is substantially equal to or slightly larger the frame portion  12 . In  FIG. 3 , the positioning protrusion  22  is not exposed beyond the bottom surface of the frame portion  12 , but not limited to. The bottom surface of the key cap  20  can further has a resting portion  24  formed at a periphery of the positioning protrusion  22  and slightly thinner than the positioning protrusion  22 . The resting portion  24  can be fixed, such as adhered, to the top surface of the frame portion  12 , so that the key cap  20  is fixed to the supporting plate  10 . This is only one embodiment according to the instant disclosure. The key cap  20  can be made of opaque material, or where corresponded to the light-pervious opening  120  of the frame portion  12  is transparent, the other portion can be colored and shaded from light. 
     Please refer to  FIG. 3 . For the frame portion  12  having the bump  122 , the resting portion  24  is partially extended on the top of the bump  122 . When the key cap  20  is pressed, the resting portion  24  moved downwardly and pushed the frame portion  12  and the bump  122  to press the dome  30 . 
     Referring to  FIG. 3A , which show a second embodiment of the key cap according to the instant disclosure. The difference between the key cap  20   a  in this embodiment and the fore-mentioned embodiment is the fixing way. The key cap  20   a  uses a hook  22   a  at the bottom surface thereof to clip to two sides of the frame portion  12 . Besides, the key cap  20   a  has a pair of resting portions  24   a  on the bottom surface thereof, so that it can be against the front portion and the rear portion of the frame portion  12  in a balance manner. The front bar  121  and the rear bar  123  of the frame portion. The resting portion  24   a  is also disposed on the bump  122 . 
     Referring to  FIG. 3B , which illustrates a third embodiment of the key cap according to the instant disclosure. The difference between this embodiment of the key cap  20   b  and the first embodiment is that the bottom surface of the key cap  20   b  only has a frame-shaped resting portion  24   b , without positioning protrusion or hook. This embodiment uses an adhesive layer  22   b  of rectangle-frame shape adhered to the frame portion  12 . The contour of the resting portion  24   b  is matched with that of the frame portion  12 . The adhesive layer  22   b  can be twin adhesive or any kinds of adhesives could use to bind. 
     Referring to  FIG. 3C , which is a side view of a supporting plate being uplifted of second embodiment according to the instant disclosure. This embodiment uses an independent uplifted block  14   b  disposed between the supporting plate  10  and the circuit board  40 . The uplifted block  14   b  could be rectangular or half-circle shaped in a side view, and is adhered to a bottom surface of the supporting plate  10 . Preferably the uplifted block  14   b  is bar-shaped and is disposed at one side of the frame portion  12  or between two neighboring rows of the frame portion  12 . 
     Referring to  FIG. 3D , which is a side view of a supporting plate being uplifted of third embodiment according to the instant disclosure. This embodiment has an uplifted portion  52  integrally protruded upward from the bearing substrate  50 . The uplifted portion  52  passes through the circuit board  40  and propped against the bottom surface of the supporting plate  10 . The shape of the uplifted portion  52  could be in square column shape or half-column. 
     Referring to  FIG. 1  and  FIG. 3 , the dome  30  is a metal slug in substantial half-sphere, which is disposed under the frame portion  12  opposite to the uplifted portion  14 . When the key cap  20  is pressed, the dome  30  conducts a corresponding circuit on the circuit board  40  (not shown) to produce a signal and provides an elastic force. The circuit board  40  in this embodiment is made of light-transmissible material, and is printed with a plurality of conductive circuits under the domes  30  correspondingly. 
     The slim keypad structure  100  of this embodiment can further include a bearing substrate  50 , which is disposed on the bottom surface of the circuit board  40 . The bearing substrate  50  is used to support the elements of the keypad structure, which could be transparent board, such as a transparent glass or plastic. The bearing substrate  50  also could be a light-guiding board as light source cooperated with LEDs, and formed with a plurality of micro-structure corresponding to the light-pervious openings  120  as back light for the key cap  20 . 
     Referring to  FIG. 1  and  FIG. 4 , wherein  FIG. 4  is a perspective cross-sectional view of slim keypad structure  100 . Another characteristic of the slim keypad structure according to the instant disclosure is that the key cap  20  does not need to print with symbols or characters. The slim keypad structure  100  can further include a displaying element  60  to show at least one symbol through the circuit board  40 , the light-pervious opening  120  of the supporting plate  10  and corresponding to the key cap  20 . Preferable the displaying element  60  is a liquid display panel, which can output different symbols by a central processing unit, such as the symbol  62  “A” shown in  FIG. 4  and displayed on the key cap  20  through the light-pervious opening  120  of the frame portion  12 . Even if the displaying element  60  is rigid enough, such as tempered glass, the bearing substrate  50  of the instant disclosure could be omitted, and the circuit board  40  is directly formed on the displaying element  60 . 
     The instant disclosure can display different symbols on one same key cap  20  through the displaying element  60 . In other words, the same one key cap can show different symbols to match with different controlling commands according to different requirements. For example, the slim keypad structure can be mounted on a tablet personal computer, and the displaying element  60  projects different symbols on the same key cap  20  according to the requirement of programs. In the example of electronic reading software, different symbols can be provided by the displaying element  60  on the same key cap  20  of one keypad structure, such as “upward”, “downward”, “forward”, “rearward”. In other electronic games, the same key cap  20  can show different symbols of “attack”, “pause” “escape” . . . etc. The circuit board  40  is electrically connected to the center processing process of the electronic device, so that the conductive circuit simultaneously produces different controlling signals correspondingly. The slim keypad structure of the instant disclosure makes electronic devices are more flexible on operations, and do not need many keypad structure. 
     The displaying element  60  also can be other types, such as printing, or light colors. For example, a LED can be mounted therein to provide different light colors. A supplementary description, the displaying element  60  is not a necessary element in the instant disclosure. For example, the key cap  20  can be made of opaque material and printed with symbol directly, which is enough for a normal operation of the slim keypad structure of the instant disclosure. 
     Referring to  FIG. 5 , which is shown the slim keypad structure  100  is disposed on an electronic device  200  according to the instant disclosure. Besides, the slim keypad structure  100 , the electronic device  200  includes a first display  220 , a second display  260  and a pivoted device  240  connected the first and second displays  220 ,  260  for a cover liftable function. The first display  220  and the second display  260  preferably can be slim liquid crystal display. The second display  260  can be used as the above-mentioned displaying element. In other words, the second display  260  of the electronic device  200  can be used to display symbol through the circuit board  40  and the light-pervious opening  120  of the supporting plate  10 , then is shown on the top surface of the key cap  20  correspondingly. In this embodiment, the symbol is shown on the key cap  20  by the second display  260 , so that the slim keypad structure  100  does not need the displaying element  60 , just needs the supporting plate  10 , the key cap  20 , the dome  30 , the circuit board  40  and the bearing substrate  50 . Even if the second display  260  of the electronic device  200  is rigid enough, the bearing substrate  50  can be omitted. 
     The supporting plate  10  of the instant disclosure can further include a fixing portion  102  extended from an outer side of the frame portion  12 . In this embodiment, the fixing portion  102  is extended outwardly from the uplifted portion  14 . The fixing portion  102  is connected to the electronic device  200 , such as to the pivoted device  240 , even is pivotably connected to the electronic device  200 . When it is lifted upward, the second display  260  can be used as other function. 
     To sum up, the instant slim keypad structure has the following disadvantages and features as followed. The slim design makes the thickness of the electronic device is reduced effectively. All the elements are simplified and easily to assembly, thus the cost can be reduced. The instant disclosure can be applied on portable electronic devices, such as mobile phone, tablet personal computer . . . etc., to provide well pressing sense of touch, instead of touch panel. The same keypad structure can show different symbols, so that the operation is more flexible. 
     The description above only illustrates specific embodiments and examples of the instant disclosure. The instant disclosure should therefore cover various modifications and variations made to the herein-described structure and operations of the instant disclosure, provided they fall within the scope of the instant disclosure as defined in the following appended claims.