Key sheet

• US 20050000788A1
• Filed: 06/07/2004
• Published: 01/06/2005
• Est. Priority Date: 06/03/2003
• Status: Active Grant

• Current Assignee: Polymatech Company Limited
• Original Assignee: Polymatech Company Limited
• Inventors: Nishimura, Takeshi
• Granted Patent: US 6,967,292 B2
• Time in Patent Office: Days
• US Class Current: 200/512
• CPC Class Codes: H01H 13/702 with contacts carried by or formed from layers in a multilayer structure, e.g. membrane switches
• CPC Class Codes: H01H 2209/006 Force isolators
• CPC Class Codes: H01H 2209/01 Increasing rigidity; Anti-creep
• CPC Class Codes: H01H 2223/0345 with keys positioned directly next to each other without an intermediate bezel or frame
• CPC Class Codes: H01H 2227/036 Minimise height
• CPC Class Codes: H01H 2229/048 Insertion moulding

Abstract

A key sheet is equipped with a keytop exposed through an operational opening with no partition frame formed in the casing of an apparatus, the keytop being adapted to be depressed into the casing, and a base sheet to which the keytop is firmly attached, in which it is possible to achieve a further reduction in the thickness of the base sheet. In this key sheet, the base sheet is equipped with a pedestal portion to which the keytop is firmly attached and a frame-like support portion supporting the pedestal portion so as to allow its displacement, wherein a clearance portion allowing the keytop to avoid press contact with the frame-like support portion at the time of depressing operation is formed in the outer edge side portion of the bottom portion of the keytop opposed to the frame-like support portion, whereby even if the pedestal portion is thin, it is possible to perform depressing operation on the keytop without any fear of the keytop being caught by the frame-like support portion.

Claims

1. A key sheet comprising a keytop exposed through an operational opening with no partition frame formed in a casing of an apparatus, the keytop being adapted to be depressed into the casing, and a base sheet to which the keytop is firmly attached,

wherein the base sheet is equipped with a pedestal portion to which the keytop is firmly attached and a frame-like support portion supporting the pedestal portion so as to allow displacement of the pedestal portion, and wherein a clearance portion allowing the keytop to avoid press contact with the frame-like support portion at a time of depressing operation is formed in an outer edge side portion of a bottom portion of the keytop opposed to the frame-like support portion.

2. A key sheet according to claim 1, wherein the base sheet is provided with a plurality of the pedestal portions and a plurality of the frame-like support portions each corresponding to each the pedestal portions.

3. A key sheet according to claim 1, wherein the frame-like support portion is formed by a reinforcing member formed of a hard resin thin plate supporting the pedestal portion.

4. A key sheet according to claim 1, wherein the frame-like support portion is formed by a resin film having a through-hole for firmly attaching the pedestal portion through bridging.

5. A key sheet according to claim 4, wherein the resin film is equipped with a reinforcing member of hard resin for regulating distortion of the base sheet.

6. A key sheet according to claim 1, wherein the pedestal portion is formed of a rubber-like elastic body.

7. A key sheet according to claim 1, wherein a surface of the base sheet to which the keytop is firmly attached is flat.

8. A key sheet according to claim 1, wherein a surface of the keytop firmly attached to the base sheet has an area smaller than that of a top surface of the keytop.

9. A key sheet according to claim 1, wherein the frame-like support portion is formed of one of a hard resin material and a resin film which has a lattice-like configuration with an outer frame.

10. A key sheet according to claim 1, wherein the frame-like support portion is formed of one of a hard resin material and a resin film which has a lattice-like configuration with no outer frame.