Pressure responsive sensor having controlled scanning speed

Abstract

A circuit and various sensor arrays are provided which facilitate the scanning of an array of pressure responsive points at higher speed than is possible with currently available circuits and sensor arrays and also provides greater flexibility in selecting scanning speed and in making a tradeoff between scanning speed and resolution. These objectives are achieved by providing a sensor array having T sets of drive electrodes, with pressure points in a predetermined pattern intersected by drive electrodes of each set and a sense electrode for each pressure point of a set. A test signal is applied simultaneously to the drive electrodes of each set, with a different test signal being applied to each set, each test signal flowing through a drive electrode to which the test signal is applied, and through pressure points intersected by such drive electrode for which the resistance is in a lowered resistance state, to the sense electrode intersecting the point, and through sensor output lines to which the sense electrodes are selectively connected. The sense electrodes may be selectively connected to an output circuit which may for example provide a separate A/D converter for each sensor output line or may multiplex the sensor output lines to a single A/D converter. For one embodiment of the invention, T=1 so that a single test pulse may be applied simultaneously to all of the pressure points of the sensor array. Various techniques are also provided for enhancing resolution in areas of interest while sacrificing resolution in areas which are not of interest so as to permit higher speed scanning to be performed without significant sacrifice in resolution.