US 4,731,694 A · Touch selection pad and method of manufacture

Abstract

A touch selection pad contains a matrix of tactile sensors each of which contains a composite material with a pressure and direction-dependent electric conductivity and a dielectric material forming a capacitor. These are provided with column electrodes and row electrodes. When touched, each of the sensors creates a series circuit comprising a resistor formed of the composite material and a capacitor formed from the dielectric having a capacitance of preferably at least 50 pF. In this matrix of tactile sensors, the pressure-dependent resistance together with the associated fixed capacity serves as the measuring variable. The touch pad due to the small spacing between the sensors has a high resolution. It can be produced in a simple manner by sequentially depositing layers on a metalized carrier by means of a thin-film technique. The row and column electrodes can be etched out of a metalized plastic cover layer and a metalized carrier, respectively, by micro structuring techniques.

Claims24

Dependent claims

A touch selection pad comprising:

(a) a matrix of tactile sensors arranged into rows and columns, each tactile sensor comprising a series circuit of a variable resistance which is part of a layer of composite material which has a pressure dependent conductivity and a capacitor comprising a layer of dielectric material having a capacitance of at least fifty picofarads;
(b) a plurality of row electrodes coupled to the rows of the matrix of tactile sensors and
(c) a plurality of column electrodes coupled to the columns of the matrix of tactile sensors.

A method of manufacturing a touch selection pad on a carrier comprising a matrix of tactile sensors arranged into rows and columns, a plurality of row electrodes coupled to the rows of the matrix of tactile sensors and a plurality of column electrodes coupled to the columns of the matrix of tactile sensors, comprising the steps of:

(a) metalizing a carrier using thin-film metalization processes;
(b) etching grooves into the metalization of the metalized carrier to form the column electrodes;
(c) applying a dielectric material as a layer over the remaining metalized portions of the carrier by thin film application processes;
(d) covering the dielectric material layer with a composite material;
(e) forming an electrically insulating covering having a flat side;
(f) applying the row electrodes to said covering;
and
(g) covering the composite material with the flat, row electrode side of the electrically insulating covering.

5 more elements

Dependencies are inferred from the claim text.

Touch selection pad and method of manufacture

Life of this patent

Touch selection pad and method of manufacture

Life of this patent

Abstract

Claims24