The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 18, 1990
Filed:
May. 26, 1989
Applicant:
Inventors:
Hiroyuki Minemura, Hitachi, JP;
Yoshio Sato, Hitachi, JP;
Nobuyoshi Tsuboi, Ibaraki, JP;
Hiroaki Koyanagi, Katsuta, JP;
Shinji Ohyama, Hitachi, JP;
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G02B / ; G02B / ; G11B / ; G11B / ;
U.S. Cl.
CPC ...
350 9611 ; 369 53 ; 350 9613 ; 350 9619 ;
Abstract
A waveguide path type optical pickup is provided for preventing a returning light from returning back to a light source. A filter for selectively allowing either Te polarized light or TM polarized light to pass through the filter is provided in an optical path from a light source to an optical path deflector. An optical part for changing the polarized state of light is provided in an optical path from the optical path changing part to an information recording medium, thereby prevent a reduction in S/N ratio or reproducing signal.