Patent ID: 7831140

Claim:
An apparatus for auto-focusing comprising: a sensing unit for sensing a current position of a lens moving within a predetermined range along a moving shaft; an A/D converter for converting a lens position value from the sensing unit into a digital signal; a lens position control unit for generating a signal for moving the lens to a target lens position determined by an auto-focusing algorithm; a driving signal generating unit for generating a square wave signal according to the signal from the lens position control unit; and an operation unit connected to the A/D converter and configured to control a time at which the A/D converter performs conversion according to the square wave signal from the driving signal generating unit; wherein the operation unit comprises: a detection unit for detecting edges of the square wave signal generated from the driving signal generating unit; and a delay unit for controlling the time at which the A/D converter performs conversion so that the A/D conversion is performed on a signal from the sensing unit after a predetermined period of time elapses from a time at which the edges are detected.