SHAPE MEMORY ALLOY ACTUATOR DRIVE DEVICE AND METHOD, AND IMAGING DEVICE USING THE SAME

摘要

A driving circuit (21) of a shape memory alloy actuator of the present invention measures by a measurement part a parameter value corresponding to a target position of a moving part that is displaced by being driven on account of the expansion and contraction of an SMA (15), which expands and contracts with temperature changes and which exhibits hysteresis in a parameter-distortion characteristic relating to the expansion and contraction, while the temperature of the SMA (15) is being raised or lowered. The driving circuit (21) sets the measured parameter value as a target parameter. The temperature of the SMA (15) is raised or lowered such that the parameter value measured by the measurement part passes the target parameter, before the crystal phase of the SMA (15) becomes a martensitic phase. Thereafter, the temperature of the SMA (15) is raised or lowered again such that the parameter value measured by the measurement part reaches the target parameter.