| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a spherical aberration compensating device for detecting more simply a spherical aberration error signal. <P>SOLUTION: In the spherical aberration compensating device, when a laser beam is irradiated to an optical recording medium through an objective lens and an information signal is recorded or reproduced, reflected light from the optical recording medium is detected by an optical detector having a plurality of light receiving regions, spherical error signals from each detected signal detected by this optical detector are generated by operation, and the spherical aberration error signal is fed back to the spherical aberration compensating means. Quadri-sected inner periphery light receiving regions A-D at the inner periphery of one light receiving plane receiving a beam by reflected light from the optical recording medium are formed in the optical detector 29A, also, when quadri-sected outer periphery light receiving regions E-H are formed at an outside of this inner periphery light receiving regions A-D and the light receiving plane is divided into eight planes, the spherical aberration error signal is calculated in a spherical aberration compensating circuit 30 using only each detected signal from the outer periphery light receiving regions E-H formed in the optical detector 29A. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
