Optical disc device and spherical aberration error signal detection method

Patent metadata

Field	Value
Publication number	US-9514778-B2
Application number	US-201514974335-A
Country	US
Kind code	B2
Filing date	Dec 18, 2015
Priority date	Jan 30, 2015
Publication date	Dec 6, 2016
Grant date	Dec 6, 2016

Abstract

There is provided an optical disc device that performs recording on a land and a groove, including an optical path splitter configured to split a luminous flux returning from an optical disc into first and second optical paths, a first detector configured to receive a whole of the luminous flux that has passed through the first optical path, a second detector configured to receive a luminous flux of an inside part of the luminous flux that has passed through the second optical path, a spherical aberration error signal generation unit configured to generate a spherical aberration error signal on the basis of a difference between a first focus error signal obtained on the basis of a detection signal of the first detector and a second focus error signal obtained on the basis of a detection signal of the second detector, a spherical aberration correction unit, and an adjustment unit.

First claim

What is claimed is:

1. An optical disc device that performs recording on lands and grooves of an optical disc, the optical disc device comprising:
an optical path splitter configured to split a luminous flux returning from the optical disc into a first optical path and a second optical path;
a first detector configured to receive a whole of the luminous flux that has passed through the first optical path;
a second detector configured to receive a luminous flux of an inside part of the luminous flux that has passed through the second optical path;
a spherical aberration error signal generation unit configured to generate a spherical aberration error signal on the basis of a difference between a first focus error signal obtained on the basis of a detection signal of the first detector and a second focus error signal obtained on the basis of a detection signal of the second detector;
a spherical aberration correction unit configured to correct spherical aberration upon receipt of the spherical aberration error signal; and
an adjustment unit configured to adjust the spherical aberration error signal,
wherein the adjustment unit adjusts a servo gain value of the spherical aberration error signal and a convergence value of the spherical aberration error signal to optimal values for each land and each groove.

2. The optical disc device according to claim 1 ,
wherein, in a case where the optical disc is a multilayer disc, the adjustment unit adjusts the servo gain value of the spherical aberration error signal and the convergence value of the spherical aberration error signal to the optimal values for each land and each groove in each layer.

3. The optical disc device according to claim 1 ,
wherein coefficient values used to generate the spherical aberration error signal are different between the lands and grooves.

4. The optical disc device according to claim 1 ,
wherein the optimal values of the servo gain value of the spherical aberration error signal and the convergence value of the spherical aberration error signal are acquired for each land and each groove at a time of production by using an adjustment standard disc, and the acquired values are held as initial values by the adjustment unit.

5. A spherical aberration error detection method of an optical disc device that performs recording on lands and grooves, the spherical aberration error detection method comprising:
obtaining a first focus error signal on the basis of a whole of a luminous flux returning from an optical disc;
obtaining a second focus error signal on the basis of an inside part of the luminous flux returning from the optical disc;
generating a spherical aberration error signal on the basis of the first focus error signal and the second focus error signal; and
adjusting a servo gain value of the spherical aberration error signal and a convergence value of the spherical aberration error signal to optimal values for each land and each groove.

6. The spherical aberration error detection method according to claim 5 ,
wherein, in a case where the optical disc is a multilayer disc, the servo gain value of the spherical aberration error signal and the convergence value of the spherical aberration error signal are adjusted to the optimal values for each land and each groove in each layer.

7. The spherical aberration error detection method according to claim 5 ,
wherein coefficient values used to generate the spherical aberration error signal are different between the lands and grooves.

8. The spherical aberration error detection method according to claim 5 ,
wherein the optimal values of the servo gain value of the spherical aberration error signal and the convergence value of the spherical aberration error signal are acquired for each land and each groove at a time of production by using an adjustment standard disc, and the acquired values are held as initial values.

Assignees

• Sony Corp

Inventors

• Ikuta Tomoya
• Kubo Takeshi
• Nakao Takashi
• Saito Kimihiro
• Yamamoto Kenji

Classifications

• G11B7/13927 Primary

  during transducing, e.g. to correct for variation of the spherical aberration due to disc tilt or irregularities in the cover layer thickness · CPC title

• G11B7/08511

  with focus pull-in only · CPC title

• G11B7/094

  Methods and circuits for servo offset compensation · CPC title

• G11B7/1353

  Diffractive elements, e.g. holograms or gratings {(diffraction gratings per se G02B5/18; holograms per se G02B5/32; grating systems G02B27/44)} · CPC title

• G11B7/0037

  with discs · CPC title