METHOD AND APPARATUS FOR DETECTING POSITION OF OBJECT LENS IN OPTICAL PICK-UP DEVICE

摘要

PURPOSE: A method and an apparatus for detecting a position of an object lens in an optical pick-up device are provided to improve performance of assembling, and to reduce manufacturing costs. CONSTITUTION: An optical reflected on an optical record surface of an optical disk is applied. A predetermined signal corresponding to the applied optical is generated. The predetermined signal is converted into a data value with respect to a position of an object lens. A calculating part detects the position of the object lens. A circuit part(61) is provided with an offset detect subtracter(44) for subtracting a signal of a sub optical and a signal of a main optical. An amplifier(43) amplifies a signal of a sub optical adder(35). Signals(33,34) of the first and second sub optical are added by the sub optical adder(35) and are output as signal values. The signal values are amplified by the amplifier(43) and inputted to the offset detect subtracter(44) to be subtracted from the signal value of the main optical. An offset is detected according to movement of the object lens.