An Optical Wireless Bistable Micro-actuator

An optical wireless bistable micro-actuator is presented in this paper. The bistable mechanism is based on antagonistic pre-shaped double beams, which have the merits of simple pre-load operation and symmetrical output force. The bistable micro-actuator was fabricated with deep reactive ion etching (DRIE) technique using silicon on insulator (SOI) wafer. The bistable beam has a thickness of 25 mu m and a depth of 400 mu m. The stroke of the bistable micro-actuator is 300 mu m. An 8 mu m thick compressive SiO2 layer is deposited on one side of the strip shaped (0.1x1x3 mm) shape memory alloy (SMA) active element, acting as the biasing spring. The SiO2 layer created a two way memory effect and eliminated the load effect of SMA element. Stroke of SMA element is tested. The wireless actuation was realized by laser heated SMA active element.