Usage of Connected Structure to Eliminate Blind Area of Piezoresistive Sensor Array

Abstract

The existing piezoresistive sensor array adopts the classical configuration called “unconnected structure”, in which the piezoresistive materials in the subelements are separated with each other. Consequently, the sensor array cannot detect the pressure applied on the region among the sub elements (i.e., blind area). To eliminate the blind area, the traditional method is to use more subelements, leading to the increase of the number of the electrodes which complicates the sensor probe. To overcome the limitation, a connected structure, in which a whole piezoresistive sheet is used in all subelements, is designed. The pressure applied on any region of the connected structure can cause the changes in the resistances of the subelements. Therefore, the region bearing pressure can be located and the pressure value can be obtained without adding electrodes. The piezoresistive sensor array made of conductive polymer composite is used as an example. The experiments show that the pressure position can be evaluated, and the pressure measurement error is less than 30 kPa within the range from 0 to 0.4 MPa. The results indicate that the usage of the connected structure can eliminate the blind area by using less electrodes than the traditional method.