Patent ID: 7535510

Claim:
A focus control apparatus for controlling a step motor and a piezoelectric material in order to control a focal distance between an electronic imaging device and a lens unit, the focus control apparatus comprising: an image calculating unit electrically connected to the electronic imaging device for processing an image signal taken by the electronic imaging device into a resolution value; a displacement controlling unit electrically connected to the image calculating unit and receiving the resolution value in order to determine an optimal focal distance between the electronic imaging device and the lens unit and output a displacement controlling signal; a step motor controller electrically connected to the step motor and the displacement controlling unit, the step motor controller receiving the displacement controlling signal for driving a step number for the step motor; a piezoelectric material controller electrically connected to the piezoelectric material and the displacement controlling unit, the piezoelectric material controller receiving the displacement controlling signal for controlling a deformation of the piezoelectric material; and a selection unit electrically connected to the step motor controller and the piezoelectric material controller for selecting one of the step motor controller and the piezoelectric material controller to control a distance between the lens unit and the electronic imaging device, wherein, the displacement controlling signal is supplied to either the step motor controller or the piezoelectric material controller to control the optimal focal distance between the electronic imaging device and the lens unit.