Pressure sensitive conductive sheet and panel switch using same

• US 7,528,337 B2
• Filed: 04/15/2008
• Issued: 05/05/2009
• Est. Priority Date: 05/15/2007
• Status: Expired due to Fees

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Tanabe, Koji, Watanabe, Hirotoshi
• Primary Examiner(s): Friedhofer; Michael A
• Application Number:
  US12/103,149
• Publication Number:
  US 20080283380A1
• Time in Patent Office: 385 Days
• Field of Search: 200/511, 200/512, 200 6142- 6144, 200/85.R, 200/86.R, 200/86.A, 341/22, 341 32- 34, 345/156, 345/168, 345/169, 345/174, 345/173, 345/176, 338/99
• US Class Current: 200/511
• CPC Class Codes: G01L 1/20 by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids of piezo-resistive materials G01L1/18; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
• CPC Class Codes: H01H 1/029 comprising conducting material dispersed in an elastic support or binding material
• CPC Class Codes: H01H 13/78 characterised by the contacts or the contact sites
• CPC Class Codes: H01H 2201/036 Variable resistance
• CPC Class Codes: H01H 2205/002 fixed to operating part
• CPC Class Codes: H01H 2227/012 Conductive rubber
• CPC Class Codes: H01H 2227/014 Conductive particles
• CPC Class Codes: H01H 2229/002 Screen printing

Abstract

A first resistor layer is formed on the lower surface of a base in film form, and at the same time, a second resistor layer in which particles of different particle diameters are dispersed is formed and layered on the lower surface of the first resistor layer, and thus, a pressure sensitive conductive sheet is formed. In this configuration, the second resistor layer in uneven form makes contact with the fixed contacts in accordance with a pressing force so that electrical connection is made via the second resistor layer and the first resistor layer, and therefore, a thin panel switch with little fluctuation in the resistance value resulting from repeated operation where a stable resistance value can be gained can be realized.

Claims

1. A pressure sensitive conductive sheet, comprising:

a base in film form;

a first resistor layer formed on a lower surface of the base; and

a second resistor layer formed and layered on a lower surface of the first resistor layer, wherein

particles of different particle diameters are dispersed inside the second resistor layer.

2. A panel switch, further comprising a substrate on a lower surface of the pressure sensitive conductive sheet according to claim 1, wherein a number of fixed contacts are formed on an upper surface of the substrate.