Abstract: An endoscope system includes: an actuator having an SMA wire and driving a moving member for moving a lens; an output control circuit; a detection circuit; and a CPU. The CPU outputs a driving signal to the output control circuit, on a basis of an instruction to move the lens, and on the basis of a position of the moving member corresponding to a resistance value detected by the detection circuit. In response to a moving instruction to move the lens from a far-point position to a near-point position, the CPU outputs the driving signal so that a current for moving the moving member from the far-point position to a position beyond the near-point position is passed through the SMA wire to heat the SMA wire. The CPU then performs preheating control, holding constant current transition control, and reheating control.

Abstract: An endoscope system includes: an actuator having an SMA wire and driving a moving member for moving a lens; an output control circuit; a detection circuit; and a CPU. The CPU outputs a driving signal to the output control circuit, on a basis of an instruction to move the lens, and on the basis of a position of the moving member corresponding to a resistance value detected by the detection circuit. In response to a moving instruction to move the lens from a far-point position to a near-point position, the CPU outputs the driving signal so that a current for moving the moving member from the far-point position to a position beyond the near-point position is passed through the SMA wire to heat the SMA wire. The CPU then performs preheating control, holding constant current transition control, and reheating control.