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. 12, 1998
Filed:
Aug. 08, 1996
Akio Yamakawa, Kanagawa, JP;
Masamichi Utsumi, Chiba, JP;
Sony Corporation, , JP;
Abstract
An optical pickup and a reproducing apparatus includes an objective lens having a hologram lens formed over the entire area of one surface thereof. A central portion of the hologram lens and peripheral portions of the hologram lens are formed differently, so that a laser beam diffracted by the central portion of the hologram lens is focused at plane A, and a laser beam diffracted by the peripheral portion is directed outward. As a result of this, the light intensity distribution after light has passed through the objective lens becomes substantially uniform, so that almost no primary ring is produced, thus preventing cross talk caused by reflected light from an adjacent track.