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.

Date of Patent:
May. 25, 1999

Filed:

Sep. 06, 1996
Applicant:
Inventors:

Kun-ho Cho, Suwon, KR;

Eung-ho Kim, Seoul, KR;

Jang-hoon Yoo, Seoul, KR;

Kyung-hwa Rim, Suwon, KR;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369112 ; 369120 ;
Abstract

An optical pickup device which is capable of reproducing and recording information from at least two discs having different thicknesses includes a light source, an objective lens provided along the light path from the light source facing the plane of a disc and having a predetermined effective diameter, a beam splitter provided between the objective lens and the light source, a photodetector for detecting the beam split from the light splitter and reflected from the disc, and light controller provided along the light path facing the photodetector lens for controlling the light of the intermediate region between near- and far axis regions of an incident light beam. The optical pickup device is simplified and the manufacturing cost therefor is low. Also, by reducing the spherical aberration effect for the light, discs having different thicknesses can be used in a single disc drive.


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