Vertical direction drive micro actuator using shape memory alloy thin film with flexible joints

This paper presents a structure of shape memory alloy (SMA) thin film actuator for a small tactile display device (Smart Button). The actuator for the smart button is required to generate displacement of larger than 20 μm and force of larger than 0.3 mN. It should be arranged in array form with pitch of less than 1 mm. In order to fulfill these requirements, a doubly supported beam type SMA thin film actuator with flexible joints at fixed ends was proposed, for the first time. The structural dependence of the displacement and generative force were analyzed by FEM method. As a result, the validity of proposed design concept and configuration to realize the actuator for smart button was confirmed.