Development of laser-driven micromachine using thin film of sputtered shape memory alloys

微型致动器，其中形状记忆合金丝由激光二极管光热驱动。由形状记忆合金制成的悬臂梁的振动幅度和作用力明显大于其他材料制成的悬臂梁。利用两个激光二极管演示了悬臂梁绕z轴的椭圆共振振动。此外，还利用8根形状记忆合金丝和一根光纤构成了激光驱动的夹持器。在300mW的激光功率下，所制作的夹持器可以夹持直径为1 mm、重量为30 mg-w的球体。虽然利用形状记忆合金的块体材料开发了微型执行器，但制作微执行器需要使用薄膜。研制了用于制备钛镍形状记忆合金薄膜的溅射设备。获得了以钛镍薄膜为表面的微悬臂梁的光热振动。结果表明，Ti-Ni薄膜表现出形状记忆效应，微悬臂梁的位移比原来的位移增加了4.3倍。

Miniature actuators, in which wires of shape-memory alloys are driven photothermally by a laser diode. A cantilever made of the shape-memory alloy showed considerably larger vibration amplitude and force than that fabricated from the other materials. Using two laser diodes, the elliptic resonance vibration of the cantilever beam around z-axis was demonstrated. In addition, a laser-driven gripper was constructed by using eight wires of shape-memory alloys which were fixed at the microfabricated plates and an optical fiber. The fabricated gripper can hold a sphere with a diameter of 1 mm and weight of 30mg-w at the laser power of 300 m W.Although miniature actuator were developed by using bulk material of shape memory alloy, it was necessary to use thin film for making micro actuator. Sputtering equipment was made for production of Ti-Ni shape memory alloy thin film. The photothermal vibration of micro-cantilever of which surface was Ti-Ni thin film was obtained. As a result, Ti-Ni thin film showed shape memory effect, and it was confirmed the displacement of the micro-cantilever increased 4.3 times than former displacement.