PRESSURE-RESPONSIVE DEVICE

PRESSURE-RESPONSIVE DEVICE Electrical signals are produced by a pressure-responsive device, such signals being indicative of the position of locally applied pressure. The device comprises a position sensor assembly which comprises a composite layer medium including electrically conductive magnetic particles (e.g. 34) in a nonconductive matrix material (e.g. 35). The medium is sandwiched between contact assemblies (e.g. 71). The particles are aligned into chains extending across the thickness of the layer, and chains include a nonconductive gap )e.g. an air space or a nonconducting layer at least on particles nearest the contact assemblies) which is bridged upon application of sufficient pressure. The medium is sandwiched between sheet electrodes, and the resulting assembly may be transparent as is advantageous in writing pad and touch-sensitive screen applications. The pressureresponsive device is suitable, e.g., as an input device in graphics information systems, in combination with transmission and display facilities.