Patent ID: 7663986
Filing Date: 2010-02-16
Classification: G11B

Abstract:
1. A servo control signal generation device corresponding to reproduction of optical disks having a reflectance after recording which is lower than that before recording and optical disks having a reflectance after recording which is higher than that before recording, said servo control signal generation device comprising: RF generation means for generating an RF signal on the basis of reflected light of an optical disk; disk discrimination means for discriminating a kind of the optical disk on the basis of the RF signal; top envelope generation means for generating a top envelope signal of the RF signal; bottom envelope generation means for generating a bottom envelope signal of the RF signal; signal generation means for selecting a signal from the top envelope signal and the bottom envelope signal and for generating a defect signal and a mirror signal on the basis of the kind of the optical disk discriminated by said discrimination means as to whether the optical disk is an optical disk having a reflectance after recording which is lower than that before recording or an optical disk having a reflectance after recording which is higher than that before recording; and polarity changing over means for changing over polarity of said mirror signal according to whether said disk discrimination means judges the optical disk to belong to a kind of optical disks having a reflectance after recording which is lower than that before recording, or said disk discrimination means judges the optical disk to belong to a kind of optical disks having a reflectance after recording which is higher than that before recording.