Integration of Stainless-Steel Tactile Bump with Inductive Tactile Sensor Array for 3D Micro Joystick Button Application

Abstract

This study presents a novel inductive tactile sensor array with rigid stainless-steel bump sensing interface for 3D micro joystick button application (Fig. 1a-b). The presented micro joystick button design using inductive sensor array and stainless-steel bump interface has several merits: (1) batch process to define and etch bumps on stainless-steel sheet, (2) compact sensing coil array using CMOS platform can distinguish the magnitude and distribution of tactile loads, and (3) polymer as spring and encapsulation layer to cover the rigid tactile bump and CMOS chip without any fragile suspended thin film structure. The design is implemented using standard TSMC 0.35 μm 2P4M CMOS process and in-house post-CMOS processes. Measurements show sensing signals from the proposed sensor array could distinguish the loading conditions for 3D micro joystick button application.