Ultrafine and crosstalk-free 2D tactile sensor by using active-matrix thin-film transistor array

Abstract

Abstract Passive matrix (PM) technologies are widely used in various fields (e.g., manufacturing, human sensing, and robotics) to visualize the tactile pressure distribution. These technologies are powerful addressing methods with simple structures, low cost, and easy fabrication steps. However, crosstalk problems have been pointed out, especially in high-resolution fields. To prevent a crosstalk occurrence, we adapt active-matrix (AM) technologies for ultrafine tactile imaging. In this work, two-dimensional (2D) tactile sensors are prepared using AM arrays fabricated through standard display processes. Pressure-sensitive resistor sheets are then attached. The sensors have 6720 px in a 90 × 90 mm sensing area with a 1.1 mm pixel pitch. The crosstalk is evaluated by pressurizing the control area of the sensor and measuring the output in the non-pressurized area. No pixel is affected by the pressure outside the pixel itself, or no crosstalk occurs. For a demonstration, static pressure from soft toy balls and dynamic foot pressure during walking are loaded to the 2D tactile sensors. The differences in the contact mode by the ball type and the pressure of each finger are observed, thanks to the 1.1 mm-pitch without crosstalk. The 2D tactile sensors presented herein will contribute to the fundamental understanding of the contact interface and will have practical usage in sport sciences, biometric identifications, and tactile sensation of robots.

Keywords

• Crosstalk-free
• Active-matrix technology
• Tactile sensor
• Foot pressure distribution