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Method of detecting focus error signal of optical head and optical recording/reproducing apparatus utilizing the same

A technology of error signal and focus shift, applied in optical recording/reproduction, optical recording head, head configuration/installation, etc., can solve problems such as superposition

Inactive Publication Date: 2006-06-07
TDK CORPARATION
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Therefore, there is a problem that the second zero-cross signal is superimposed on the focus shift error signal generated by the differential astigmatism method

Method used

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  • Method of detecting focus error signal of optical head and optical recording/reproducing apparatus utilizing the same
  • Method of detecting focus error signal of optical head and optical recording/reproducing apparatus utilizing the same
  • Method of detecting focus error signal of optical head and optical recording/reproducing apparatus utilizing the same

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no. 1 Embodiment approach

[0070] A method of detecting a focus shift error signal of an optical head according to a first embodiment of the present invention and an optical recording and reproducing apparatus using the method will be described with reference to FIGS. 1 to 11 . First, the schematic configuration of the optical head 1 included in the optical recording and reproducing device 150 according to this embodiment will be described with reference to FIGS. 1 to 5 . The optical head 1 of the present embodiment is capable of recording or reproducing information on two optical recording media 15 having different physical track pitch lengths. The optical recording medium 15 (first optical recording medium 15 a ) having a relatively large physical track pitch is a DVD-RAM or an optical recording medium having an equivalent physical track pitch. In addition, the optical recording medium 15 (second optical recording medium 15 b ) having a relatively small physical track pitch is DVD-ROM, DVD±R / RW, or an...

no. 2 Embodiment approach

[0164] Next, a method of detecting a focus shift error signal of an optical head according to a second embodiment of the present invention and an optical recording and reproducing apparatus using the method will be described with reference to FIGS. 12 to 14 . The optical head of this embodiment is characterized in that it uses a special diffractive element including a wave-shaped grating pattern as a diffractive element necessary for forming sub-beams on an information recording surface of an optical recording medium. The structure of the optical head of this embodiment is the same as that of the optical head 1 of the above-mentioned first embodiment except that a special diffraction grating is used instead of the diffraction grating 19, and therefore description thereof will be omitted. In addition, the configuration of the optical recording and reproducing device of this embodiment is the same as that of the optical recording and reproducing device 150 of the above-mentioned ...

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Abstract

The present invention relates to a focus shift error signal detection method of an optical head used to control the focus position of an objective lens of a converging light beam in an optical recording medium and an optical recording and reproducing device using the method. A method for detecting a focus shift error signal of an optical head capable of detecting a focus shift error signal with attenuated track cross signals among a plurality of optical recording media having different physical track pitches, and an optical recording and reproducing apparatus using the method. Make the light beam emitted from the laser diode (3) enter the diffraction grating (19), and divide it into the main beam (27) and the sub-beams (29a, 29b) of ± 1 order; receiving the main light beam (27) and ±1 order sub-beams (29a, 29b) reflected by the optical recording medium (15); using the error signal detection part (31) to detect the attenuation of the track crossing signal based on the electrical signal after photoelectric conversion The focus shift error signal FES.

Description

technical field [0001] The present invention relates to a focus shift error signal detection method of an optical head for controlling the focus position of an objective lens of a converging light beam in an optical recording medium and an optical recording and reproducing device using the method. Background technique [0002] The optical recording and reproducing apparatus is equipped with an optical head, which is used to record information in a predetermined area of ​​a plurality of tracks formed along, for example, the circumferential direction of a disk-shaped optical recording medium and a plurality of tracks in the radial direction of the optical recording medium, or The information recorded in the predetermined area is reproduced. Optical heads include a recording-only type used only for recording information on an optical recording medium, a playback-only type used only for reproducing information, and a recording-reproducing type capable of bo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G11B7/00G11B7/09G11B7/12
CPCG11B7/0903G11B7/0908G11B7/0943G11B2007/0006G11B7/09
Inventor 涩谷义一冈祯一郎
Owner TDK CORPARATION