Patent ID: 7574126

Claim:
A lens driving apparatus, comprising: an imaging lens including a focus adjustment lens that forms an image of a subject; an imaging device that images light of the subject by way of the imaging lens; a lens position controller including a driver that shifts the imaging lens in a direction of an optical axis with respect to a lens barrel, the lens position controller outputting a periodic driving signal and controlling a position of the imaging lens using the driver; a position detection sensor whose output value varies with a position of the imaging lens; a lens position calculator that determines a phase of the driving signal as a reference position of the imaging lens when the output value of the position detection sensor reaches a threshold value; and a reference position storage that stores the reference position, wherein the lens position calculator determines a position obtained by performing addition or subtraction on the reference position read out from the reference position storage as a judgment position, detects an output value of the position detection sensor at a timing in synchronization with the driving signal that drives the driver and at the judgment position, and judges whether the output value of the position detection sensor at the judgment position reaches the threshold value or not, so as to determine the reference position again.