Optical pickup for reading optical disk information provided with error detecting means by knife edge test

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United States of America Patent

PATENT NO 4868377
SERIAL NO

07151548

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ATTORNEY / AGENT: (SPONSORED)

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Abstract

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According to an optical system of an optical pickup of the present invention, beam is split into two portions by a light refracting member which is disposed between a condenser lens and a light receiving element, a portion of beam entering into the light refracting member is utilized for detecting tracking errors, and the remaining portion of beam which is not permitted to enter into the light refracting member is utilized for detecting focussing errors by a knife edge test. With the above-mentioned constitution of the optical system, a tracking error composition is prevented from interferring with the focussing error detection and, at the same time, both the tracking errors and focussing errors can be detected by one light receiving element. Thus, the number of component parts can be reduced and the optical system itself can be made compact.

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Patent Owner(s)

Patent OwnerAddress
ASAHI KOGAKU KOGYO KABUSHIKI KAISHA A CORP OF JAPAN36-9 MAENOCHO 2-CHOME ITABASHI-KU TOKYO

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Inventor(s)

Inventor Name Address # of filed Patents Total Citations
Nishikawa, Koichiro Tokyo, JP 108 251

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