| 摘要 |
PURPOSE:To eliminate a DC offset of a servo signal due to a stray light generated in an optical head and to obtain a stable error signal. CONSTITUTION:Peripheral light-receiving areas 12i and 12j are provided in the vicinity of signal detecting light-receiving areas 12e and 12f of a photodetector, and a differential between signals obtained in the signal detecting lightreceiving areas 12e and 12f and signals obtained in the peripheral light- receiving areas 12i and 12j is taken. Thereby a DC offset due to a stray light is canceled. |
