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Optical disk device and tracking-controlling method

A technology for optical discs and equipment, applied in the field of optical disc equipment and tracking control, can solve the problems of unstable track search operation, unstable tracking control, and difficulty in detecting track crossing signals, etc., and achieve search and other processing and stable search and other processing effects

Inactive Publication Date: 2004-06-16
SONY CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0012] Therefore, in the related art, a method of generating a track cross signal has a problem that it is difficult to detect a track cross signal in an unrecorded portion of an optical disc capable of mass recording such as DVD.
If it is difficult to detect the track crossing signal TCS, the track search operation becomes unstable in the unrecorded part, causing problems such as instability in the start of tracking control

Method used

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  • Optical disk device and tracking-controlling method
  • Optical disk device and tracking-controlling method
  • Optical disk device and tracking-controlling method

Examples

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no. 1 example

[0036] (1-1) Structure of the first embodiment

[0037] Fig. 3 is a block diagram showing an optical disk device according to a first embodiment of the present invention. In this optical disc apparatus 21, an optical disc 22 is an optical disc capable of high-density recording, such as a DVD, and it is rotated at a predetermined rotational speed by a spindle motor (not shown).

[0038] The optical pickup 23 uses a diffraction grating to convert the laser beam emitted from the semiconductor laser into −1 order, 0 order and +1 order diffracted lights, and the objective lens 24 focuses these diffracted lights onto the information recording surface of the optical disc 22 . The optical pickup 23 further guides the returned light of the diffracted light into a predetermined light receiving device through the objective lens 24 , and outputs the light detection result of the light receiving device that has undergone current-to-voltage conversion to the matrix amplifier 25 . The optic...

no. 3 example

[0087] FIG. 8 is a plan view showing a beam spot position in an optical disc apparatus according to a third embodiment of the present invention, in contrast to the beam spot positions shown in FIGS. 4 and 7 . The optical disc device in this embodiment is constructed in the same manner as the optical disc device 21 according to the first or second embodiment, except for the beam spot position and related components.

[0088] In this embodiment, the side beams are still set to a position offset by about (1 / 4+n)P relative to the main beam in the direction of the inner-outer circumference of the disc on the sides where the main beam starts and ends the scan Upscan, where n represents an integer set to a value of 1.

[0089] Therefore, in the present embodiment, the side beam is not allowed to scan on the target track before the main beam, thereby preventing an increase in temperature at the accessed position caused by scanning of the side beam before the main beam. Therefore, a p...

no. 4 example

[0091] In the present embodiment, the beam spot of the side beam is set with respect to the beam spot of the main beam to satisfy the expression (3 / 4+n)P instead of the above-described expression (1 / 4+n)P. Along with this, in addition to the light detection result of the light receiving device receiving the side beam, the light detection result obtained from the area in the vicinity of the light receiving device receiving the main beam is processed to generate the tracking error signal TE. A track cross signal TCS is generated whose polarity is reversed.

[0092] Specifically, in the present embodiment, using the reference numerals given to the light receiving surfaces shown in FIG. 4, the track crossing signal TCS given by TSC=(H-G)-(F-E) is generated, and The tracking error signal TE given by TE=PPm-k(G-F)flt. Except for the structure related to the generation of the tracking error signal TE and the track crossing signal TCS, other components are constructed in a similar ma...

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Abstract

In a configuration in which side beams scan in positions that are offset with respect to a main beam by approximately ( 1 / 4 +n)P or ( 3 / 4 +n)P in the radial direction of an optical disk, a differential signal is generated from push-pull signals of the return lights of the side beams to generate a track-cross signal. In a configuration in which side beams scan in positions that are offset with respect to a main beam by approximately ( 1 / 4 +n)P or ( 3 / 4 +n)P in the radial direction of an optical disk, far-side or near-side light detection results of the return lights of the side beams are processed and computed with respect to a push-pull signal of the return light of the main beam.

Description

technical field [0001] The present invention relates to a tracking control method of an optical disc device such as applied to a DVD to reliably generate a track cross signal. Background technique [0002] In related art optical disc devices such as DVD-R and DVD±RW, a tracking error signal is generated using a so-called differential push-pull technique. [0003] Figure 1 shows the connection diagram of the return light processing used in the differential push-pull technology. FIG. 1 shows access to an optical disk by land recording or groove recording, in which a land L and a groove G are formed to have substantially the same width. The optical disc device uses a diffraction grating to convert the laser beam emitted from the semiconductor laser into -1 order, 0 order and +1 order diffracted light, and radiates the -1 order, 0 order and +1 order diffracted light to the information of the disc through the objective lens record on the surface. Return light of the diffracted...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G11B7/085G11B7/09G11B7/095
CPCG11B7/0903G11B7/0943G11B7/09
Inventor 石川秀树
Owner SONY CORP