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Title:
METHOD AND DEVICE FOR CORRECTING ASTIGMATIC DIFFERENCE OF OPTICAL HEAD
Document Type and Number:
Japanese Patent JP2605636
Kind Code:
B2
Abstract:

PURPOSE: To provide an inexpensive method and device for correcting astigmatic difference easy for manufacture by solving a large problem in which a tracking error signal of an optical head is different from an RF signal maximum focus offset by generating the astigmatic difference in an optical system to correct the astigmatic difference.
CONSTITUTION: A first oblique glass 6 and a second oblique glass 7 are arranged between the laser light source 2 of the optical head and a collimate lens 3 or in the converged collimate beam of the optical head. The oblique angle of the first oblique glass 6 is made the angle of the positive direction, and the second oblique glass 7 is arranged so as to be angle set at the angle in the negative direction of the oblique angle. Then, by rotating respective oblique glasses around an optical axis simultaneously or at the respective angles, adjustment is performed.


Inventors:
Matsui, Tsutomu
Application Number:
JP1994000250803
Publication Date:
April 30, 1997
Filing Date:
October 17, 1994
Export Citation:
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Assignee:
NEC CORP
International Classes:
G02B27/09; G11B7/08; G11B7/135; (IPC1-7): G11B7/08; G02B27/09; G11B7/135
Domestic Patent References:
JP6243479A
JP7153109A
JP815637A
Attorney, Agent or Firm:
後藤 洋介 (外2名)