Space resolution improvement for pressure measurement by using a single conductive polymer composite sheet in area array

Abstract

There are no piezoresistive materials in the districts among the sub units of the traditional area array for the compressive pressure sensor, which results in that the pressure applied on the districts among the sub units cannot be detected. To increase the space resolution of the pressure measurement (i.e. to make the pressure applied on the districts among the sub units detectable), a single sheet made of conductive polymer composite is used as the piezoresistive materials in all sub units. This can ensure that there exist composites in the districts among the sub units, which results in that the pressure applied on anywhere of the area array (including the districts among the sub units) can cause the changes in the electrical resistances of all sub units. The resistance-change of each sub unit decreases with the increase of the distance between the sub unit and the sub district bearing the pressure. The normalized response strength (NRS) of the sub unit is defined as the ratio of the relative-resistance-change of the sub unit to the maximum value of the relative-resistance-changes of all sub units. There is a threshold for NRS. The sub unit is defined as the “strong/weak sub unit” when the NRS of the sub unit is higher/lower than the threshold. Through analyzing the distributions of the strong and weak sub units in the area array, the position where the pressure is applied can be located. Through using the piecewise linear interpolation and the calibration data for the piezoresistivities of the sub units, the value of the pressure can be achieved. The aforementioned method is verified by the experimental results on the area array based on a single sheet made of carbon nanotube filled silicone rubber composite.