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:
May. 30, 2000
Filed:
Dec. 12, 1997
Applicant:
Inventors:
Shinji Fujita, Yokohama, JP;
Hidenori Shinohara, Hitachinaka, JP;
Toshio Sugiyama, Yokohama, JP;
Nobuo Imada, Fujisawa, JP;
Yukio Fukui, Machida, JP;
Assignees:
Hitachi, Ltd., Tokyo, JP;
Hitachi Media Electronics Co., Ltd., Iwate-ken, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369112 ; 369 58 ;
Abstract
The dichroic mirror or a polarized beam splitter is installed between a mirror and an objective lens as a beam synthesize/split means, in an optical system corresponding to a second disk and an optical system corresponding to a first disk arranged so as to form a two-layer structure. The dimension of the optical head in the width, length, and thickness directions are designed moderately.