# US 2019/0378666 A1 · Keyboard device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0378666 A1 - Document ID: US20190378666A1 - Status: Published application - Kind: A1 - Application number: 16/110,721 - Filed: 2018-08-23 - Published: 2019-12-12 - Earliest claimed: 2018-06-08 - Assignees: Primax Electronics Ltd. - Applicants: Primax Electronics Ltd. - Inventors: YI-CHEN WANG - Web page: https://patentgrep.com/patent/US20190378666A1 ## CPC - H01H 3/125: {using a scissor mechanism as stabiliser} - H01H 13/14: Operating parts, e.g. push-button - H01H 13/04: Cases; Covers - H01H 13/10: Bases; Stationary contacts mounted thereon - H01H 13/20: Driving mechanisms - H01H 13/702: with contacts carried by or formed from layers in a multilayer structure, e.g. membrane switches - H01H 2233/07: Cap or button on actuator part - H01H: ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES (contact cables H01B7/10; electrolytic self-interrupters H01G9/18; emergency protective circuit arrangements H02H; switching by electronic means without contact-making H03K17/00) ## Abstract A keyboard device includes a membrane circuit board, a base plate and a key. The key includes a keycap, a connecting element and a stabilizer bar. The connecting element is connected between the keycap and the base plate. The stabilizer bar is connected between the keycap and the connecting element. While the keycap is moved upwardly or downwardly relative to the base plate, the stabilizer bar is swung to stabilize the key. Since the stabilizer bar is connected between the keycap and the connecting element, the stabilizer bar does not readily collide with or knock on the base plate. During the process of operating the key, the generated noise is reduced. Consequently, the operating comfort to the user is enhanced. ## Claims ### Claim 1 A keyboard device, comprising: a membrane circuit board comprising a membrane switch; a base plate comprising a plate body and a base coupling structure, wherein the plate body is located under the membrane circuit board, and the base coupling structure is protruded upwardly and penetrated through the membrane circuit board; and a key comprising: a keycap located over the membrane circuit board, wherein when the keycap is moved downwardly relative to the membrane circuit board, the membrane switch is triggered; a connecting element connected between the keycap and the base plate; and a stabilizer bar connected between the keycap and the connecting element, wherein while the keycap is moved upwardly or downwardly relative to the base plate, the stabilizer bar is swung to stabilize the key. ### Claim 2 (depends on 1) The keyboard device according to claim 1, wherein the connecting element comprises a first frame and a second frame, wherein while the keycap is moved upwardly or downwardly relative to the membrane circuit board, the first frame and the second frame are swung relative to each other. ### Claim 3 (depends on 2) The keyboard device according to claim 2, wherein the stabilizer bar comprises a transverse bar part and a hook part, wherein the hook part is located at an end of the transverse bar part, the transverse bar part is connected with the keycap, and the hook part is connected with the second frame. ### Claim 4 (depends on 3) The keyboard device according to claim 3, wherein a first end of the second frame further comprises a frame coupling part, and the hook part of the stabilizer bar is pivotally coupled to the frame coupling part, wherein the keycap further comprises a keycap sliding groove, and the transverse bar part of the stabilizer bar is movable within the keycap sliding groove. ### Claim 5 (depends on 4) The keyboard device according to claim 4, wherein the frame coupling part is located at a lateral side of the first end of the second frame. ### Claim 6 (depends on 3) The keyboard device according to claim 3, wherein a first end of the second frame further comprises a frame sliding groove, and the hook part of the stabilizer bar is movable within the frame sliding groove, wherein the keycap further comprises a keycap coupling part, and the transverse bar part of the stabilizer bar is pivotally coupled to the keycap coupling part. ### Claim 7 (depends on 6) The keyboard device according to claim 6, wherein the frame sliding groove is located at a lateral side of the first end of the second frame. ### Claim 8 (depends on 2) The keyboard device according to claim 2, wherein the keycap further comprises a first keycap connecting part and a second keycap connecting part, wherein the first keycap connecting part is connected with a first end of the first frame, and the second keycap connecting part is connected with a second end of the second frame. ### Claim 9 (depends on 2) The keyboard device according to claim 2, wherein the base coupling structure comprises a first base connecting part and a second base connecting part, wherein the second base connecting part is connected with a second end of the first frame, and the first base connecting part is connected with a first end of the second frame. ### Claim 10 (depends on 1) The keyboard device according to claim 1, wherein the key further comprises an elastic element, and the elastic element is connected between the keycap and the membrane circuit board and comprises a contacting part, wherein while the keycap is depressed, the elastic element is compressed and the membrane switch is pushed by the contacting part, wherein when the keycap is not depressed, the keycap is returned to an original position in response to an elastic force provided by the elastic element. ### Claim 11 A keyboard device, comprising: a membrane circuit board comprising a membrane switch; a base plate comprising a plate body and a base coupling structure, wherein the plate body is located under the membrane circuit board, and the base coupling structure is protruded upwardly and penetrated through the membrane circuit board; and a key comprising: a keycap located over the membrane circuit board, wherein when the keycap is moved downwardly relative to the membrane circuit board, the membrane switch is triggered; a first connecting element connected between the keycap and the base plate; a second connecting element connected between the keycap and the base plate; and a stabilizer bar comprising a transverse bar part, a first hook part and a second hook part, wherein the first hook part and the second hook part are respectively located at two ends of the transverse bar part, the transverse bar part is connected with the keycap, the first hook part is connected with the first connecting element, and the second hook part is connected with the second connecting element, wherein while the keycap is moved upwardly or downwardly relative to the base plate, the stabilizer bar is swung to stabilize the key. ### Claim 12 (depends on 11) The keyboard device according to claim 11, wherein the first connecting element comprises a first frame and a second frame, and the second connecting element comprises a third frame and a fourth frame, wherein while the keycap is moved upwardly or downwardly relative to the membrane circuit board, the first frame and the second frame are swung relative to each other and the third frame and the fourth frame are swung relative to each other. ### Claim 13 (depends on 12) The keyboard device according to claim 12, wherein the first hook part of the stabilizer bar is connected with the second frame, and the second hook part of the stabilizer bar is connected with the fourth frame. ### Claim 14 (depends on 13) The keyboard device according to claim 13, wherein a first end of the second frame further comprises a first frame coupling part, and the first hook part of the stabilizer bar is pivotally coupled to the first frame coupling part, wherein a first end of the fourth frame further comprises second frame coupling part, and the second hook part of the stabilizer bar is pivotally coupled to the second frame coupling part, wherein the keycap further comprises a keycap sliding groove, and the transverse bar part of the stabilizer bar is movable within the keycap sliding groove. ### Claim 15 (depends on 14) The keyboard device according to claim 14, wherein the first frame coupling part is located at a lateral side of the first end of the second frame, and the second frame coupling part is located at a lateral side of the first end of the fourth frame. ### Claim 16 (depends on 13) The keyboard device according to claim 13, wherein a first end of the second frame further comprises a first frame sliding groove, and the first hook part of the stabilizer bar is movable within the first frame sliding groove, wherein a first end of the fourth frame further comprises a second frame sliding groove, and the second hook part of the stabilizer bar is movable within the second frame sliding groove, wherein the keycap further comprises a keycap coupling part, and the transverse bar part of the stabilizer bar is pivotally coupled to the keycap coupling part. ### Claim 17 (depends on 16) The keyboard device according to claim 16, wherein the first frame sliding groove is located at a lateral side of the first end of the second frame, and the second frame sliding groove is located at a lateral side of the first end of the fourth frame. ### Claim 18 (depends on 12) The keyboard device according to claim 12, wherein the keycap further comprises a first keycap connecting part, a second keycap connecting part, a third keycap connecting part and a fourth keycap connecting part, wherein the first keycap connecting part is connected with a first end of the first frame, the second keycap connecting part is connected with a second end of the second frame, the third keycap connecting part is connected with a first end of the third frame, and the fourth keycap connecting part is connected with a second end of the fourth frame. ### Claim 19 (depends on 12) The keyboard device according to claim 12, wherein the base coupling structure comprises a first base connecting part, a second base connecting part, a third base connecting part and a fourth base connecting part, wherein the second base connecting part is connected with a second end of the first frame, the first base connecting part is connected with a first end of the second frame, the fourth base connecting part is connected with a second end of the third frame, and the third base connecting part is connected with a first end of the fourth frame. ### Claim 20 (depends on 11) The keyboard device according to claim 11, wherein the key further comprises an elastic element, and the elastic element is connected between the keycap and the membrane circuit board and comprises a contacting part, wherein while the keycap is depressed, the elastic element is compressed and the membrane switch is pushed by the contacting part, wherein when the keycap is not depressed, the keycap is returned to an original position in response to an elastic force provided by the elastic element.