| 摘要 |
PURPOSE: A device for detecting an amount of bending of an optical disc is provided to control a focus offset and the velocity of a spindle motor on the bases of an amount of bending of a disc, thereby realizing stable data search and extract. CONSTITUTION: A device for detecting an amount of bending of an optical disc includes a plurality of resistors(110) for applying signals applied from a photo diode to a differential amplifier, the differential amplifier(120) for determining amplification degrees of the signals input from the photo diode via the resistors differently, a filtering part(130) for removing noise components of high frequency from the output from the bending amount detecting device, and a bending amount level sensor(140) for controlling a velocity of a spindle motor(11) by sensing a level of the bending of the optical sensor and inputting signals to a microprocessor(50) for controlling focus offset in the vertical direction by the detected bending amount level.
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