Key sheet

• US 20050139460A1
• Filed: 12/13/2004
• Published: 06/30/2005
• Est. Priority Date: 12/25/2003
• Status: Active Grant

• Current Assignee: Polymatech Company Limited
• Original Assignee: Polymatech Company Limited
• Inventors: Hosaka, Junko
• Granted Patent: US 7,034,235 B2
• Time in Patent Office: Days
• US Class Current: 200/314
• CPC Class Codes: H01H 13/703 characterised by spacers between contact carrying layers
• CPC Class Codes: H01H 13/704 characterised by the layers, e.g. by their material or structure H01H13/703 takes precedence
• CPC Class Codes: H01H 13/705 characterised by construction, mounting or arrangement of operating parts, e.g. push-buttons or keys
• CPC Class Codes: H01H 2209/006 Force isolators
• CPC Class Codes: H01H 2209/01 Increasing rigidity; Anti-creep
• CPC Class Codes: H01H 2209/048 metallic
• CPC Class Codes: H01H 2227/002 Layer thickness
• CPC Class Codes: H01H 2229/048 Insertion moulding
• CPC Class Codes: H01H 2239/008 Static electricity considerations

Abstract

A key sheet includes a base sheet and a plurality of key tops arranged on the base sheet. The base sheet includes an elastic member formed of a rubber-like elastic body and a light-reflective reinforcing member. The light-reflective reinforcing member having at least one surface constitutes the metal-containing face.

Claims

1. A key sheet comprising a base sheet, and a plurality of key tops arranged on the base sheet and exposed through an operation opening which is formed in a casing of an apparatus without a partition frame,

wherein the base sheet comprises an elastic member formed of a rubber-like elastic body and having a plurality of floating portions to which the key tops are firmly attached, and a light-reflective reinforcing member that supports the floating portions such that the floating portions are capable of depression displacement, and

wherein at least one face of the light-reflective reinforcing member comprises a metal-containing face.

2. A key sheet according to claim 1, further comprising a reinforcing member formed of hard resin, and a metal layer provided on a surface of the reinforcing member,

wherein the light-reflective reinforcing member includes a laminate of the reinforcing member and the metal layer.

3. A key sheet according to claim 1, wherein the light-reflective reinforcing member comprises a reinforcing member made of metal.

4. A key sheet according to claim 2, wherein the metal layer has a thickness within a range of 10 nm to 80 nm.

5. A key sheet according to claim 2, wherein the key sheet includes an illumination type key sheet in which the key tops are illuminated by light emitted from an illumination light source arranged on a back surface of the base sheet.

6. A key sheet according to claim 2, further comprising a cutaway portion allowing entry of the illumination light source, the cutaway portion being formed in the elastic member at each of intersection positions between vertical frames and horizontal frames of the reinforcing member having a grid-like configuration.

7. A key sheet according to claim 2, wherein the light-reflective reinforcing member is provided to one face of the elastic member situated on a key top side.

8. A key sheet according to claim 2, further comprising a thick-walled portion formed in the elastic member,

wherein the light-reflective reinforcing member is provided to an upper face of the thick-walled portion.

9. A key sheet according to claim 2, wherein the light-reflective reinforcing member is provided to one face of the elastic member situated on a side opposite to the key tops.

10. A key sheet according to claim 2, further comprising a thick-walled portion formed in the elastic member,

wherein the light-reflective reinforcing member is provided in a bottom face of the thick-walled portion.

11. A key sheet according to claim 3, wherein the reinforcing member made of metal has a thickness within a range of 50 μ

m to 2,000 μ

m.

12. A key sheet according to claim 3, wherein the key sheet includes an illumination type key sheet in which the key tops are illuminated by light emitted from an illumination light source arranged on a back surface of the base sheet.

13. A key sheet according to claim 3, further comprising a cutaway portion allowing entry of the illumination light source, the cutaway portion being formed in the elastic member at each of intersection positions between vertical frames and horizontal frames of the reinforcing member having a grid-like configuration.

14. A key sheet according to claim 3, wherein the light-reflective reinforcing member is provided to one face of the elastic member situated on a key top side.

15. A key sheet according to claim 3, further comprising a thick-walled portion formed in the elastic member,

wherein the light-reflective reinforcing member is provided to an upper face of the thick-walled portion.

16. A key sheet according to claim 3, wherein the light-reflective reinforcing member is provided to one face of the elastic member situated on a side opposite to the key tops.

17. A key sheet according to claim 3, further comprising a thick-walled portion formed in the elastic member,

wherein the light-reflective reinforcing member is provided in a bottom face of the thick-walled portion.