Title:
OPTICAL PICKUP DEVICE AND INFORMATION RECORDING/ REPRODUCING DEVICE
Document Type and Number:
Japanese Patent JP3920072
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To detect a tracking error signal in which offset due to axis deviation of an incident light beam in an objective lens from an optical axis or due to a relative tilt of the objective lens and an information recording medium is not generated without increasing the number of laser beams, or to detect an objective lens position signal, etc.
SOLUTION: Light spots PS1 and PS2 on a pair of photodetectors 8a and 8b are respectively formed on the basis of reflected light from an information recording medium 6 of a laser beam S1 on a land and a laser beam S2 on a groove in the information recording medium 6. Push-pull signals of the respective photodetectors 8a and 8b fetch light reflectively diffracted with a guiding groove formed on the information recording medium 6 as an output difference in respective two light receiving surfaces (A, B) and (C, D) on the photodetectors 8a and 8b arranged symmetrically with respect to a track center, and a tracking error signal TE is obtained by these respective push-pull signals.
Inventors:
Hideaki Hirai
Application Number:
JP2001318261A
Publication Date:
May 30, 2007
Filing Date:
October 16, 2001
Export Citation:
Assignee:
株式会社リコー
International Classes:
G11B7/005; G11B7/09; G11B7/085; G11B7/125; (IPC1-7): G11B7/09; G11B7/005; G11B7/085; G11B7/125
Domestic Patent References:
| JP5298730A | ||||
| JP2149935A | ||||
| JP61094246A | ||||
| JP7093764A | ||||
| JP2000331356A | ||||
| JP2001167454A | ||||
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Attorney, Agent or Firm:
Mitsutake Murayama