Rotational actuator for optical device and camera module having the same

摘要

Disclosed is a rotational actuator for an optical device, which includes a rotary shaft capable of freely rotating at a fixed position; a first shape-memory alloy wire fixed in a first direction to give a rotation moment to the rotary shaft, the first shape-memory alloy wire making length contraction with respect to the rotary shaft when an electric current is applied thereto; a second shape-memory alloy wire fixed in a second direction opposite to the first direction to give a rotation moment with respect to the rotary shaft, the second shape-memory alloy wire making length contraction with respect to the rotary shaft when an electric current is applied thereto; and a control unit configured to supply an electric current to the first shape-memory alloy wire when rotating the rotary shaft in the first direction and supply an electric current to the second shape-memory alloy wire when rotating the rotary shaft in the second direction.