Patent ID: 8692925

Claim:
An optical system drive device comprising: an optical system movable in a moving range; an urging member urging the optical system in an optical axis direction; a shape-memory alloy actuator for moving the optical system in the optical axis direction; a current applying section for supplying a current to the actuator; a measurement section for measuring a characteristic value of the actuator; a driving control section for controlling the supply current to the current applying section according to the characteristic value measured by the measurement section; and a signal output section for outputting a prescribed signal to the driving control section when the characteristic value of the actuator measured by the measurement section reaches a value corresponding to a target position of the optical system while making the shape-memory alloy of the actuator change the length at least in an extending mode when moving the optical system to the target position, wherein the signal output section outputs a second stop signal to the driving control section when the characteristic value reaches a value corresponding to a first position of the optical system in an autofocus control according to the characteristic value of the actuator measured by the measurement section while making the characteristic value changed from one corresponding to an initial position where the optical system is held before the autofocus control for moving a position of the optical system in a stepwise fashion to another of the extending mode in the length of the shape-memory alloy.