GB2045527A - The variable resistance pressure sensitive mat or switch - Google Patents

Abstract

A pressure sensitive mat comprises a pressure sensitive laminate which produces a significant change in electrical resistance upon the application of external pressure. The laminate consists of a sandwich of carbon impregnated polythene between two layers of metallic foil. Electrical connection to the laminate is made to the two layers of foil. The mat may have an outer layer of heavy duty polythene. <IMAGE>

Description

SPECIFICATION Variable resistance pressure sensitive mat The attached diagrams show the construction of a simple device which laminates foil of aluminium or similar material i.e. copper foil etc. with a polythene which has been impregnated with carbon or graphite which gives it a property of variable resistance with respect to pressure.

This construction is then protected by two external layers of heavy duty polythene which affords protection to the foil laminates.

Wire is soldered to the foil and presented as connecting electrodes. Externally to the laminate construction. The principle could also be described as a switch.

1. The principle of using an impregnated layer of polythene to form a pressure sensitive variable resistance laminate using metalic foil as the electrical plates or connecting surfaces is I believe inventive and not been done in this way before.

2. My application states that this can be used as a switch using a small area of laminate constructed in the same manner or applying the copper coating of a printed circuit board as one of the electrical connections with a layer of metalic foil forming the other electrical connection. This I claim is an inventive step and not been done before.

3. Any electrical circuit which requires a variable resistance to control it such as speed control on motors foot controls on musical instruments will lend themselves to this application and I claim that any use of this principle in such circuits does not detract from my original inventive step and would make similar applications invalid.

CLAIMS (25 Jun 1980) 1. A pressure-sensitive mat, comprising a laminate of two metsL.toil electrodes and an interposed foil of electrically insulating material loaded with electridally conductive particles, such that the electrical resistance between the electrodes varies in accordance with pressure applied to the mat.

2. A pressure-sensitive mat as claimed in claim 1, further comprising two outer layers of protective material covering the opposite sides of the laminate.

3. A pressure-sensitive mat as claimed in claim 1 or 2, in which the interposed foil comprises polythene loaded with carbon or graphite.

4. A pressure-sensitive mat substantially as herein described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (4)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Variable resistance pressure sensitive mat The attached diagrams show the construction of a simple device which laminates foil of aluminium or similar material i.e. copper foil etc. with a polythene which has been impregnated with carbon or graphite which gives it a property of variable resistance with respect to pressure. This construction is then protected by two external layers of heavy duty polythene which affords protection to the foil laminates. Wire is soldered to the foil and presented as connecting electrodes. Externally to the laminate construction. The principle could also be described as a switch. CLAIMS 1. The principle of using an impregnated layer of polythene to form a pressure sensitive variable resistance laminate using metalic foil as the electrical plates or connecting surfaces is I believe inventive and not been done in this way before. 2. My application states that this can be used as a switch using a small area of laminate constructed in the same manner or applying the copper coating of a printed circuit board as one of the electrical connections with a layer of metalic foil forming the other electrical connection. This I claim is an inventive step and not been done before. 3. Any electrical circuit which requires a variable resistance to control it such as speed control on motors foot controls on musical instruments will lend themselves to this application and I claim that any use of this principle in such circuits does not detract from my original inventive step and would make similar applications invalid. CLAIMS (25 Jun 1980)

1. A pressure-sensitive mat, comprising a laminate of two metsL.toil electrodes and an interposed foil of electrically insulating material loaded with electridally conductive particles, such that the electrical resistance between the electrodes varies in accordance with pressure applied to the mat.

2. A pressure-sensitive mat as claimed in claim 1, further comprising two outer layers of protective material covering the opposite sides of the laminate.

3. A pressure-sensitive mat as claimed in claim 1 or 2, in which the interposed foil comprises polythene loaded with carbon or graphite.

4. A pressure-sensitive mat substantially as herein described with reference to the accompanying drawings.