| US 7,539,108 B2 | ||
| Optical information reproduction apparatus and optical information reproduction method | ||
| Tsutomu Maruyama, Chiba (Japan); and Isao Ichimura, Tokyo (Japan) | ||
| Assigned to Sony Corporation, (Japan) | ||
| Filed on Oct. 17, 2005, as Appl. No. 11/250,481. | ||
| Claims priority of application No. P2004-309956 (JP), filed on Oct. 25, 2004. | ||
| Prior Publication US 2006/0087937 A1, Apr. 27, 2006 | ||
| Int. Cl. G11B 7/00 (2006.01) | ||
| U.S. Cl. 369—53.35 [369/124.11] | 4 Claims |
| 1. An optical information reproduction apparatus for reproducing a recording signal by irradiating a light beam onto a recording
surface of an optical information recording medium having at least two information recording layers and by receiving reflected
light of the light beam, the optical information reproduction apparatus comprising:
extraction means for extracting an envelope signal of a reproduction signal when the reproduction signal reproduced by focusing
the light beam onto one information recording layer in the plural information recording layers has been modulated by interlayer
crosstalk from another information recording layer;
distortion correction means for correcting the distortion of the target reproduction signal caused by the interlayer crosstalk
by gain-adjusting the reproduction signal containing DC components so that the envelope signal becomes constant;
determination means for determining whether the optical information recording medium has plural information recording layers
or a single information recording layer on the basis of a reading from the information recording layer; and
control means for allowing the extraction means and the distortion correction means to operate when it is determined by the
determination means that the optical information recording medium has plural information recording layers and for otherwise
allowing signal processing means to perform signal processing without allowing the extraction means and the distortion correction
means to operate.
|