Polymer-based flexible tactile sensor up to 32 × 32 arrays integrated with interconnection terminals

A polymer-based flexible tactile sensor array integrated with interconnection terminals was fabricated with polymer MEMS technologies and electroplating. The tactile sensing arrays were made as 4 × 4, 8 × 8, 16 × 16 and 32 × 32 sensing elements connected with a pluggable connector. Both the tactile sensor arrays and the interconnection terminals were fabricated together on the same polymer substrate in order to integrate them as a sensor module. The tactile sensor array with FFC (flexible flat cable) can be easily connected with the sensor array mounting PCB board by inserting the flexible cable into the pluggable connector socket on the board. The number and pitch of the fabricated interconnection terminals for 32 × 32 arrays were 68 and 500 μm, respectively. Continuous normal force ranging 0–1 N was applied to a unit tactile sensor for evaluating the tactile sensor characteristics through the integrated interconnection terminals. The measured resistance increased linearly with normal force in the range of 0–0.6 N but the resistance variation rate decreased above 0.6 N. The variation rate of the resistance is about 2.0%/N in the range of 0–0.6 N and 1%/N in the range of 0.6–1 N. The characterization of the tactile sensor array for the rod bar and a fingertip was successfully evaluated using the custom designed controller and the window-based 3D display software.