Patent Application
20200013566
The present invention relates to a keyboard device, and more particularly to a keyboard device with a membrane switch circuit member.
Generally, the widely-used peripheral input device of a computer system includes for example a mouse device, a keyboard device, a trackball device, or the like. Via the keyboard device, characters or symbols can be directly inputted into the computer system. As a consequence, most users and most manufacturers of input devices pay much attention to the development of keyboard devices.
Hereinafter, a key structure with a scissors-type connecting element in a conventional keyboard will be illustrated with reference to
The scissors-type connecting element 12 is arranged between the base plate 15 and the keycap 11, and the base plate 15 and the keycap 11 are connected with each other through the scissors-type connecting element 12. The scissors-type connecting element 12 comprises a first frame 121 and a second frame 122. A first end of the first frame 121 is connected with the keycap 11. A second end of the first frame 121 is connected with the base plate 15. The rubbery elastomer 13 is enclosed by the scissors-type connecting element 12. The membrane switch circuit member 14 comprises plural key intersections (not shown). When one of the plural key intersections is triggered, a corresponding key signal is generated. The rubbery elastomer 13 is disposed on the membrane switch circuit member 14. Each rubbery elastomer 13 is aligned with a corresponding key intersection. When the rubbery elastomer 13 is depressed, the rubbery elastomer 13 is subjected to deformation to push the corresponding key intersection of the membrane switch circuit member 14. Consequently, the corresponding key signal is generated.
The operations of the conventional key structure 1 in response to the depressing action of the user will be illustrated as follows. Please refer to
Conventionally, the keys of the keyboard device are arranged in a keyboard matrix. When one key is depressed, a keyboard controller realizes the information of the depressed key according to the column information and the row information and outputs the corresponding key signal. Generally, the intersection between each row and each column of the keyboard matrix represents a corresponding key intersection. When one keycap is triggered, the keyboard device starts to scan the keyboard matrix and recognizes which keycap is depressed. For example, the keyboard controller scans all columns of the keyboard matrix sequentially. If the corresponding signal is received from a specified row when a specified column is scanned by the keyboard controller, the keyboard controller can realize which key is depressed according to the received column information and row information.
The minimum matrix unit of the keyboard matrix is composed of four keys. When any of the four keys is depressed, the corresponding key signal can be successfully generated. When two of the four keys are arbitrarily depressed, the keyboard controller can realize which keys are triggered. However, when three keys are simultaneously depressed, the information of two rows and the information of two columns are transmitted to the keyboard controller. Since four keys are defined by two rows and two columns, the keyboard controller cannot recognize the three depressed keys from the four keys according to the row information and the column information only. Under this circumstance, the fourth key is erroneously judged as the on-state key. That is, the fourth key is referred as a ghost key.
For avoiding the ghosting problem, the keyboard device is further equipped with plural diodes near the corresponding key intersections. Since the current is allowed to pass through the membrane switch circuit member in one direction through the arrangement of the diodes, the erroneous judgement of the ghosting problem is avoided. However, the approach of installing diodes near the corresponding key intersection still has some drawbacks. Firstly, the diode is not cost-effective. Consequently, the cost of the keyboard device is increased. Secondly, the plural diodes on the membrane switch circuit member increase the thickness of the membrane switch circuit member. The increased thickness of the membrane switch circuit member is detrimental to slimness of the keyboard device. Thirdly, the process of welding the diodes at the positions near the corresponding key intersections is very complicated.
Therefore, there is a need of providing a keyboard device with low cost and capable of avoiding the ghosting problem
An object of the present invention provides a keyboard device with low cost and capable of avoiding the ghosting problem.
Another object of the present invention provides a keyboard device with reduced thickness and having a function of avoiding the ghosting problem.
In accordance with an aspect of the present invention, there is provided a keyboard device. The keyboard device includes a base plate, at least one key structure and a membrane switch circuit member. The at least one key structure is exposed outside the keyboard and connected with the base plate. The membrane switch circuit member is arranged between the base plate and the at least one key structure. When the membrane switch circuit member is pressed by the at least one key structure, at least one key signal is correspondingly generated. The membrane switch circuit member includes a first board and a second board. The first board includes a first circuit pattern and a conductive paste mark. The first circuit pattern is disposed on the first board. A first contact of the first circuit pattern is formed on the first board. The conductive paste mark is disposed on the first circuit pattern and located near the first contact. The second board includes a second circuit pattern. A second contact of the second circuit pattern is formed on the second board. When the second contact and the first contact are contacted with each other, the at least one key signal is generated. The conductive paste mark is sprayed or dispensed on the first circuit pattern so as to define an equivalent resistance.
In accordance with another aspect of the present invention, there is provided a keyboard device. The keyboard device includes a base plate, at least one key structure and a membrane switch circuit member. The at least one key structure is exposed outside the keyboard and connected with the base plate. The membrane switch circuit member is arranged between the base plate and the at least one key structure. When the membrane switch circuit member is pressed by the at least one key structure, at least one key signal is correspondingly generated. The membrane switch circuit member includes a first board and a second board. The first board includes a conductive paste mark and a first circuit pattern. The conductive paste mark is disposed on the first circuit pattern. The first circuit pattern is disposed on the first board to cover the conductive paste mark. A first contact of the first circuit pattern is formed on the first board. The second board includes a second circuit pattern. A second contact of the second circuit pattern is formed on the second board. When the second contact and the first contact are contacted with each other, the at least one key signal is generated. The conductive paste mark is sprayed or dispensed on the first board so as to define an equivalent resistance.
In an embodiment, the first board further includes a first insulation layer to cover the first circuit pattern and the conductive paste mark, so that the first contact is exposed outside the first insulation layer and the first board is insulated. The second board further includes a second insulation layer to cover the second circuit board, so that the second contact is exposed outside the second insulation layer and the second board is insulated.
From the above descriptions, the membrane switch circuit member of the keyboard device of the present invention is specially designed. The conductive paste marks are dispensed or sprayed on the first board, the second board or the circuit pattern to define the equivalent resistance. The equivalent resistance is effective to avoid the ghosting problem. Since the conductive paste marks are formed by the dispensing process or the spraying process, the layout area of the conductive paste marks can be easily increased or decreased. In other words, the equivalent resistances of the conductive paste marks can be adjusted according to the required resistance. In such way, the equivalent resistances of all conductive paste marks very close. Since the difference between the equivalent resistances of different conductive paste marks are not large, the problem of the conventional printing process is avoided. Moreover, since the keyboard device of the present invention is not equipped with the costly diodes, the fabricating cost of the keyboard device is reduced. Moreover, since the first contact and the second contact are separated from each other through the first insulation layer and the second insulation layer, it is not necessary to install the separation layer in the membrane switch circuit member. That is, the three-layered structure of the conventional membrane switch circuit member is replaced by the two-layered structure (i.e., the first board and the second board) of the membrane switch circuit member of the present invention. Consequently, the thickness of the keyboard device is reduced.
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:
For solving the drawbacks of the conventional technologies, the present invention provides a keyboard device.
Hereinafter, the structure of the keyboard device of the present invention will be illustrated with reference to
The membrane switch circuit member 21 is arranged between the base plate 22 and the plural key structures 20. When the membrane switch circuit member 21 is pressed by one of the key structures 20, a corresponding key signal is generated. The base plate 22 is located under the membrane switch circuit member 21. The plural key structures 20 and the membrane switch circuit member 21 are supported by the base plate 22. As shown in
In this embodiment, the keyboard device 2 is a keyboard device for a notebook computer. Moreover, the connecting element 202 is a scissors-type connecting element (also referred as a scissors member) that is swung with the movement of the keycap 201. Moreover, the elastic element 203 is a rubbery elastomer. The examples of the above components are presented herein for purpose of illustration and description only. In another embodiment, the crater-shaped connecting elements for a desktop computer can be used to connect and move the keycaps. In a further embodiment, the keycaps are moved upwardly or downwardly in response to magnetic forces.
Please refer to
The second board 212 comprises a second circuit pattern 2121 and a second insulation layer 2122. Moreover, plural second contacts 2121A of the second circuit pattern 2121 are formed on the second board 212. When one of the second contacts 2121A and the corresponding first contact 2111A are contacted with each other, the corresponding key signal is generated. The second circuit pattern 2121 is covered by the second insulation layer 2122. The second insulation layer 2122 provides the insulating function to the second board 212. The second insulation layer 2122 is not aligned with the second contacts 2121A. Consequently, the second contacts 2121A are exposed outside the second insulation layer 2122. The first insulation layer 2113 and the second insulation layer 2122 are contacted with each other. Consequently, the first contacts 2111A and the second contacts 2121A are separated from each other through the first insulation layer 2113 and the second insulation layer 2122.
In an embodiment, both of the first board 211 and the second board 212 are made of polyethylene terephthalate (PET). The second circuit pattern 2121 is made of silver paste and formed on the second board 212 by a printing process. In an embodiment, the first insulation layer 2113 is a UV-resistant layer. Moreover, the first insulation layer 2113 is printed on the first circuit pattern 2111 and the conductive paste marks 2112 to cover the first circuit pattern 2111 and the conductive paste marks 2112. Similarly, the second insulation layer 2122 is also a UV-resistant layer. The second insulation layer 2122 is printed on the second circuit pattern 2121 to cover the second circuit pattern 2121.
The structure of the membrane switch circuit member 21 is shown in
The present invention further provides a second embodiment, which is distinguished from the first embodiment.
As shown in
The second board 312 comprises a second circuit pattern 3121 and a second insulation layer 3122. The structures of the second board 312, the second circuit pattern 3121 and the second insulation layer 3122 are similar to those of the first embodiment, and are not redundantly described herein.
The waterproof adhesive 313 is arranged between the first insulation layer 3113 and the second insulation layer 3122 to prevent the foreign liquid (not shown) from contacting with the first circuit pattern 3111 or the second circuit pattern 3121. In other words, the waterproof adhesive 313 provides a waterproof function. Moreover, the waterproof adhesive 313 is not aligned with the first contacts (not shown) and the second contacts (not shown). Consequently, the electric connection of the membrane switch circuit member 31 is not influenced by the waterproof adhesive 313.
The structure of the membrane switch circuit member 31 is shown in
The present invention further provides a third embodiment, which is distinguished from the above embodiments.
The membrane switch circuit member 41 comprises a first board 411 and a second board 412. The first board 411 comprises a first circuit pattern 4111 and a first insulation layer 4112. Moreover, plural first contacts 4111A of the first circuit pattern 4111 are formed on the first board 411. The first circuit pattern 4111 is covered by the first insulation layer 4112. The first insulation layer 4112 provides the insulating function to the first board 411. The first insulation layer 4112 is not aligned with the first contacts 4111A. Consequently, the first contacts 4111A are exposed outside the first insulation layer 4112.
The second board 412 comprises a second circuit pattern 4121, plural conductive paste marks 4122 and a second insulation layer 4123. The second circuit pattern 4121 is formed on a surface of the second board 412. Moreover, plural second contacts 4121A are formed on the second board 412. The conductive paste marks 4122 are formed on the second circuit pattern 4121 and located near the corresponding second contacts 4121A. The second circuit pattern 4121 and the conductive paste marks 4122 are covered by the second insulation layer 4123. The second insulation layer 4123 provides the insulating function to the second board 412. The second insulation layer 4123 is not aligned with the second contacts 4121A. Consequently, the second contacts 4121A are exposed outside the second insulation layer 4123. In an embodiment, the second circuit pattern 4121 is printed on the second board 412. Moreover, the conductive paste marks 4122 are sprayed on the second circuit pattern 4121. The conductive paste marks 4122 have the shapes of strips. Consequently, an equivalent resistance is defined by the conductive paste marks 4122. The equivalent resistance is effective to avoid the ghosting problem.
The structure of the membrane switch circuit member 41 is shown in
From the above descriptions, the membrane switch circuit member of the keyboard device of the present invention is specially designed. The conductive paste marks are dispensed or sprayed on the first board, the second board or the circuit pattern to define the equivalent resistance. The equivalent resistance is effective to avoid the ghosting problem. Since the conductive paste marks are formed by the dispensing process or the spraying process, the layout area of the conductive paste marks can be easily increased or decreased. In other words, the equivalent resistances of the conductive paste marks can be adjusted according to the required resistance. In such way, the equivalent resistances of all conductive paste marks very close. Since the difference between the equivalent resistances of different conductive paste marks are not large, the problem of the conventional printing process is avoided. Moreover, since the keyboard device of the present invention is not equipped with the costly diodes, the fabricating cost of the keyboard device is reduced. Moreover, since the first contact and the second contact are separated from each other through the first insulation layer and the second insulation layer, it is not necessary to install the separation layer in the membrane switch circuit member. That is, the three-layered structure of the conventional membrane switch circuit member is replaced by the two-layered structure (i.e., the first board and the second board) of the membrane switch circuit member of the present invention. Consequently, the thickness of the keyboard device is reduced.
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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 106137176 | Oct 2017 | TW | national |
This application is a divisional application of application Ser. No. 15/878,973, filed Jan. 24, 2018, the content of which is incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 15878973 | Jan 2018 | US |
| Child | 16576598 | US |
