Vertical thick-film resistors as load sensors

A vertical thick-film resistor for a fine-pitch-array load sensor has been developed. This sensor can be used for measuring the relief (footprint) of a load force. The thick-film resistor, with a sheet resistivity of 1 Mohm/sq., is vertically oriented and terminated with a conductive layer at the bottom and on the top of the resistor layer. Sensitivity to the load (pressure) is based on the piezoresistive effect of the thick-film resistor. The experimental work on the sensing element resulted in a vertical resistor with a resistance of 2500 ohm and a sensitivity (dR/R) of about 1.3% at 6 bar pressure. Because of high density and large number of sensing elements, the whole system is divided into a number of segments. Each segment integrates 16 sensing elements (vertical thick-film resistors), 16 diodes, and 16 terminals for the inter-segment connections. (C) 2001 Elsevier Science Ltd. All rights reserved.