A shape memory alloy thick film actuator array for narrow pitched planar tactile display device

This paper presents a MEMS type shape memory alloy (SMA) thick film actuator array for a tactile display which renders texture to human finger skin by mechanical stimulations. We propose a planar tactile display combined with SMA thick film actuator array (5 × 5 array, 1 mm pitch). The deflectable planar spring-shaped SMA actuators with micro-heater circuits were batch-fabricated from a 10-μm thick SMA film. Fabrication process techniques were newly developed, and then the SMA actuator array device was realized. The generated force and displacement of the SMA actuator at high and room temperatures were 40 mN and 25 mN, respectively, at initial deflection of 100 μm. With a bias spring combination, the reversible force generation and displacement can be estimated as 5 mN and 20 μm which are large enough for mechanical stimulation to human skin.