Bounceless switch apparatus

• US 4,315,238 A
• Filed: 04/16/1980
• Issued: 02/09/1982
• Est. Priority Date: 09/24/1979
• Status: Expired due to Term

• Current Assignee: Interlink Electronics Incorporated
• Original Assignee: Franklin N. Eventoff
• Inventors: Eventoff, Franklin N.
• Primary Examiner(s): Albritton, C. L.
• Application Number:
  US06/140,921
• Time in Patent Office: 664 Days
• Field of Search: 338/69, 338/99, 338/100, 338/114, 200/5 A, 200/264, 340/365 A, 252/518, 84/DIG. 7
• US Class Current: 338/99
• CPC Class Codes: B60C 23/0408 transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver
• 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: H01C 10/106 on resistive material dispersed in an elastic material H01C10/103 and H01C10/12 take precedence; for electric switches H01H1/029
• CPC Class Codes: H01H 1/029 comprising conducting material dispersed in an elastic support or binding material
• 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 13/703 characterised by spacers between contact carrying layers
• CPC Class Codes: H01H 13/80 characterised by the manner of cooperation of the contacts, e.g. with both contacts movable or with bounceless contacts
• CPC Class Codes: H01H 13/807 characterised by the spatial arrangement of the contact sites, e.g. superimposed sites
• CPC Class Codes: H01H 2201/002 bounceless
• CPC Class Codes: H01H 2203/012 Microprotrusions
• CPC Class Codes: H01H 2203/02 Interspersed fingers
• CPC Class Codes: H01H 2211/032 Pressure sensitive layer on contacts
• CPC Class Codes: H01H 2213/002 with external pressure
• CPC Class Codes: H01H 2213/016 in adhesive layer
• CPC Class Codes: H01H 2215/008 Part of substrate or membrane
• CPC Class Codes: H01H 2221/02 pneumatic
• CPC Class Codes: H01H 2225/002 superimposed
• CPC Class Codes: H01H 2225/006 more then one pole
• CPC Class Codes: H01H 2227/012 Conductive rubber
• CPC Class Codes: H01H 2227/014 Conductive particles
• CPC Class Codes: H01H 2229/002 : Screen printing
• CPC Class Codes: H01H 2229/012 : Vacuum deposition
• CPC Class Codes: H01H 2229/014 : Electro deposition
• CPC Class Codes: H01H 2229/028 : Adhesive
• CPC Class Codes: H01H 2229/038 : Folding of flexible printed circuit
• CPC Class Codes: H01H 2231/018 : Musical instrument
• CPC Class Codes: H01H 2239/016 : combined with start switch, discrete keyboard
• CPC Class Codes: H01H 2239/078 : Variable resistance by variable contact area or point
• CPC Class Codes: Y10S 84/07 : Electric key switch structure

Abstract

A pressure responsive, variable resistance, analog switch has first and second conductors interleaved in spaced-apart relationship and disposed on a base member. An insulative spacer ring is positioned around and rises above the first and second conductors. A resilient cover sheet is attached to the top of the insulative spacer ring in spaced relationship over the conductors to define an enclosure between the resilient cover sheet and the base member. A pressure sensitive resistive conductor composition is disposed on the resilient cover sheet or on the conductors in the enclosure to interconnect a resistance between the first and second conductors when the resilient cover sheet is depressed against the conductors. The amount of resistance so interconnected varies inversely to the amount of pressure exerted.

Claims

1. A bounceless switch apparatus having a junction resistance which varies inversely with a pressure applied normally thereto, comprising:

a first conductor member;

a pressure sensitive composition layer including a particulated semiconducting material disposed for covering the first conductor member in intimate electrically conducting contact therewith, the layer pressure sensitive composition layer having a first surface with a multiplicity of microprotrusions of the particulate semiconducting material extending from the first surface for providing a multiplicity of surface contact locations; and

a second conductor member positioned in substantially nonelectrically conducting relationship to the pressure sensitive composition layer whereby the bounceless switch apparatus is normally open, the switch being closed in response to a pressing force applied to urge the second conductor member and the first surface together for increasing the physical contact between the microprotrusions and the second conductor, to enable electrical conduction through the contacting microprotrusions, the amount of electrical conduction increasing as the amount of pressing force is increased and decreasing as the amount of pressing force is decreased.

3. The bounceless switch of claim 1 wherein the first pressure sensitive composition layer is less than about 0.001 inch thick.

5. The bounceless switch of claims 1 or 2 wherein the particulated semiconducting material is particulated molybdenum disulfide.

6. The bounceless switch of claim 5 wherein the particle size of the particulated molybdenum disulfide is less than one micron.

2. A bounceless switch apparatus having a surface contact resistance which varies inversely with a pressure applied normally thereto comprising:

a first conductor member;

a first pressure sensitive composition layer including a particulated semiconducting material disposed for covering the first conductor member in intimate electrically conducting contact therewith and further having a first surface having a multiplicity of microprotrusions extending therefrom;

a second conductor member; and

a second pressure sensitive composition layer including the particulated semiconducting material disposed for covering the second conductor in intimate, electrically conducting contact therewith and further having a second surface having a multiplicity of microprotrusions extending therefrom, the first and second surfaces being positioned in normally electrically nonconducting relationship with each other, at least one of the first and second conductor members being resiliently movable in response to a pressing force applied thereagainst so that the multiplicity of microprotrusions extending from the first and second pressure sensitive composition layers are urged against one another to enable electrical conduction between the first and second conductor members, the amount of electrical conduction increasing as the pressing force is increased and decreasing as the amount of pressing force is decreased.

4. The bounceless switch apparatus of claim 2 wherein the first and second pressure sensitive composition layers are less than about 0.001 inch thick.