Tearable membrane switch with resinous bounded silver-palladium alloy contacts

• US 5,973,283 A
• Filed: 05/27/1998
• Issued: 10/26/1999
• Est. Priority Date: 06/17/1997
• Status: Expired due to Fees

• Current Assignee: DENSO Corporation, Electric Industry Company Limited, Kokuriku Electric Industry Co., Ltd.
• Original Assignee: DENSO Corporation, Hokuriku Electric Industry Company Limited
• Inventors: Motoki, Yoshimitsu, Ishiyama, Ichirou, Yokoe, Tetsushi, Ariga, Katsuhiko, Teraoka, Masayasu
• Primary Examiner(s): SCOTT, JAMES R
• Application Number:
  US09/084,403
• Time in Patent Office: 517 Days
• Field of Search: 200/5 A, 200/61.54, 200/512-517, 200/262-270, 75/228, 75/245-248, 252/514, 420/501, 420/505
• US Class Current: 200/512
• CPC Class Codes: B60Q 5/003 mounted on the steering wheel
• CPC Class Codes: B60R 21/21658 with integrated switches, e.g. horn switches
• CPC Class Codes: H01H 1/023 having a noble metal as the basic material
• CPC Class Codes: H01H 11/048 by powder-metallurgical processes
• CPC Class Codes: H01H 13/70 having a plurality of operating members associated with different sets of contacts, e.g. keyboard mounting together a plurality of independent switches H02B
• CPC Class Codes: H01H 13/785 characterised by the material of the contacts, e.g. conductive polymers
• CPC Class Codes: H01H 2201/024 precious
• CPC Class Codes: H01H 2201/03 Composite
• CPC Class Codes: H01H 2231/026 Car
• CPC Class Codes: H05K 1/095 for polymer thick films, i.e. having a permanent organic polymeric binder
• CPC Class Codes: H05K 3/247 Finish coating of conductors by using conductive pastes, inks or powders

Abstract

A membrane switch having a pair of flexible printed boards and a pair of contacts respectively disposed on said printed boards. The contacts are formed of powdered alloy of silver and palladium bounded by resinous material, and a conductive layer of silver powder is disposed between the flexible printed board and the contact. Preferably, the powdered alloy contains 50-97 weight percent silver and palladium in the remainder of weight percent.

Claims

1. A membrane switch comprising a pair of flexible printed boards and a pair of contacts respectively disposed on said printed boards, wherein

each of said contacts comprises powdered alloy of silver and palladium bounded by resinous material.

2. A membrane switch as claimed in claim 1, further comprising a pair of conductive layers of silver powder each of which is disposed between one of said flexible printed boards and one of said contacts.

3. A membrane switch as claimed in claim 1, wherein said powdered alloy contains 50-97 weight percent silver.

4. A membrane switch as claimed in claim 1, wherein said powdered alloy contains 50-90 weight percent silver.

5. A membrane switch as claimed in claim 1, wherein each of said contacts contains 91-95 weight percent powdered alloy.

6. A membrane switch as claimed in claim 1, wherein each of said contacts contains 93-94 weight percent powdered alloy.

7. A membrane switch as claimed in claim 1, wherein particle diameter of said powdered alloy is between 0.5 μ

m and 5.0 μ

m.

8. A membrane switch as claimed in claim 1, wherein particle diameter of said powdered alloy is between 0.5 μ

m and 2.5 μ

m.

9. A membrane switch as claimed in claim 1, wherein each of said contacts comprises a printed layer of powdered alloy.

10. A membrane switch as claimed in claim 1, wherein one of said flexible printed board comprises a base film sheet having a tear line composed of a plurality of grooves and notches.

11. A membrane switch as claimed in claim 5, wherein said powdered alloy contains 50-97 weight percent silver.

12. A membrane switch as claimed in claim 5, wherein said powdered alloy contains 50-90 weight percent silver.

13. A membrane switch as claimed in claim 5, wherein particle diameter of said powdered alloy is between 0.5 μ

m and 5.0 μ

m.

14. A membrane switch as claimed in claim 5, wherein particle diameter of said powdered alloy is between 0.5 μ

m and 2.5 μ

m.