Patent ID: 8189093

Claim:
A camera module, comprising: an imaging optical system; a shape memory alloy which is configured to move the imaging optical system as a driven member, which is biased in a first direction in an optical axis direction of the imaging optical device, in a second direction which is in the optical axis direction and is different from the first direction when the shape memory alloy is supplied with an electric current; a drive section for supplying the shape memory alloy with electric current; a shape memory alloy resistance calculating section for calculating a resistance of the shape memory alloy when the shape memory alloy is supplied with the electric current by the drive section, a position of the driven member in the optical direction and the resistance of the shape memory alloy being in nonlinear correlation; and a control section configured to control, based on the resistance of the shape memory alloy calculated by the shape memory alloy resistance calculating section, the supply of the electric current to the shape memory alloy by the drive section; said control section being configured, after the camera module is powered on, to perform an initial operation in which the control section moves the driven member to a reference position by controlling the supply of the electric current by the drive section so that the resistance calculated by the shape memory alloy resistance calculating section is equal to a resistance of the shape memory alloy when the driven member is located at the reference position; and said control section being configured, after the initial operation and when performing autofocusing, to control the supply of the electric current, which is set so as to correct the nonlinear correlation, to the shape memory alloy so that the resistance to the shape memory alloy is equal to each of target resistances, which correspond to a plurality of equidistantly located target positions, one after another, so that the driven member is moved sequentially to the target positions by identical distances.