Key button structure for handheld mobile phone and its similar instrument, and method for forming the same

• US 20020167787A1
• Filed: 05/13/2002
• Published: 11/14/2002
• Est. Priority Date: 05/11/2001
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Saito, Shuichi, Kitamura, Hiromu
• Granted Patent: US 6,887,001 B2
• Time in Patent Office: Days
• US Class Current: 361/625
• CPC Class Codes: H01H 13/7006 comprising a separate movable contact element for each switch site, all other elements being integrated in layers
• CPC Class Codes: H01H 2217/01 Off centre actuation
• CPC Class Codes: H01H 2221/002 integral with membrane
• CPC Class Codes: H01H 2229/064 Eliminating tolerances
• CPC Class Codes: H04M 1/23 Construction or mounting of dials or of equivalent devices; Means for facilitating the use thereof by improving visibility H04M1/22
• CPC Class Codes: H04M 1/724 User interfaces specially adapted for cordless or mobile telephones

Abstract

A key button switch structure for use in a handheld mobile phone, comprises an input button 1 having a push-down pressure transmitting projection A1 and a button inclination preventing projection B 3 both projected from a bottom surface of the input button, integrally with the input button. Two electrodes A9 and B 10 are formed on a substrate 8 fixed to a body casing 6. A dome-like switch contact 7 is provided to be pushed down by the push-down pressure transmitting projection A1 of the input button when the input button is depressed, thereby to electrically contact both the two electrodes. Thus, since the button inclination preventing projection B 3 is provided, even in the case that an action center line of the dome-like switch contact is not coincident with an input pressure center line of the input button, when the input button is depressed, the electrodes A9 and B 10 formed on the substrate 8 are surely electrically interconnected by the dome-like switch contact effectively uniformly collapsed by the push-down pressure transmitting projection A1 of the input button.

Claims

1. A key button switch structure for use in a handheld mobile phone and its similar instrument, the key button switch structure comprising an input button having a projection, two electrodes formed on a substrate, and a dome-like switch contact to be pushed down by said projection of said input button when said input button is depressed, thereby to electrically contact both said two electrodes, wherein said input button is so configured to uniformly transmit a push-down pressure applied to said input button, from a bottom surface of said projection of said input button to said dome-like switch contact in the case that an action center line of said dome-like switch contact is not coincident with an input pressure center line of said input button.

2. A key button switch structure claimed in claim 1 wherein said input button includes a push-down pressure transmitting projection and a button inclination preventing projection formed on a bottom surface of said input button, integrally with said input button.

3. A key button switch structure claimed in claim 2 wherein said input button includes a recess formed in said bottom surface of said input button, at a side of said push-down pressure transmitting projection opposite to a button inclination preventing projection side.

4. A method for forming a key button switch structure for use in a handheld mobile phone and its similar instrument, the method including the steps of forming an input button having a projection, forming two electrodes on a substrate, and providing a dome-like switch contact to be pushed down by said projection of said input button when said input button is depressed, thereby to electrically contact both said two electrodes, wherein said input button is so configured to uniformly transmit a push-down pressure applied to said input button, from a bottom surface of said projection of said input button to said dome-like switch contact in the case that an action center line of said dome-like switch contact is not coincident with an input pressure center line of said input button.

5. A method claimed in claim 4 wherein the forming of said input button includes forming said input button integrally with a push-down pressure transmitting projection and a button inclination preventing projection both projected from a bottom surface of said input button.

6. A method claimed in claim 5 wherein the forming of said input button also includes formation of a recess in said bottom surface of said input button, at a side of said push-down pressure transmitting projection opposite to a button inclination preventing projection side.