Rapid Fabrication of Flexible Pressure Sensor Array

Abstract

Flexible pressure sensor arrays are of increasing interest but their fabrication tends to be complex and time- consuming. In this work we propose an inexpensive, rapid fabrication approach for flexible pressure sensor arrays. The sensor consists of a matrix of pressure-sensitive resistive elements sandwiched by patterned electrode strips that are bonded to flexible tape substrates. The fabrication uses a commercially available vinyl-cutting machine to cut out patterned electrodes and sensing “pixels", from a copper tape sheet and a carbon-impregnated polyethylene sheet (Velostat), respectively, and it uses transfer tapes to facilitate the bonding of the electrodes to the adhesive tape substrates. The entire fabrication takes approximately 15 minutes, in contrast to several hours required with a previously reported approach for fabricating similar sensors. The spatial resolution achieved by the proposed method is also higher, with each sensing unit occupying an area as small as 3 mm by 3 mm. Due to the programmable nature of the cutting machine, the proposed method can be used to readily fabricate flexible sensors with versatile patterns. Various tests have been conducted to demonstrate the effectiveness of the fabricated sensors, with a 14-by-14 sensor array successfully mapping the pressure profiles under finger touch, loading of a hand sanitizer bottle, and grasping around a cup.