Title:
光ディスク装置
Document Type and Number:
Japanese Patent JP4701251
Kind Code:
B2
Abstract:
A focus error signal is generated by a first-order diffracted light diffracted by regions 23b, 24b on a hologram plane 2a, and an offset of a tracking error signal is canceled by first-order diffracted light diffracted by regions 21a, 22a, 23a, 24a on the hologram plane 2a. Consequently, even when there is an error in the substrate thicknesses of optical discs, jitter of a reproduction signal at a focus control point can be reduced by decreasing the distance between the focus control point and the point where the jitter is minimized.
Inventors:
Hiroaki Matsumiya
Aoji Nishiwaki
Aoji Nishiwaki
Application Number:
JP2007551032A
Publication Date:
June 15, 2011
Filing Date:
December 06, 2006
Export Citation:
Assignee:
Panasonic Corporation
International Classes:
G11B7/09; G11B7/13; G11B7/135
Domestic Patent References:
| JPH03245326A | 1991-10-31 | |||
| JP2004342166A | 2004-12-02 | |||
| JP2000021014A | 2000-01-21 |
Attorney, Agent or Firm:
Ikeuchi, Sato & Partners