Patent ID: 8427913

Claim:
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: a RF generator which generates a RF signal on the basis of reflected light of an optical disk; a top envelope generator which generates a top envelope signal of the RF signal; a bottom envelope generator which generates a bottom envelope signal of the RF signal; and a signal selector which selects a signal from the top envelope signal and the bottom envelope signal on the basis of a kind of the optical disk 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 generates a defect signal on the basis of the selected signal.