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:
Aug. 17, 1999
Filed:
Apr. 25, 1997
Yang-Oh Choi, Seoul, KR;
Daewoo Electronics Co., Ltd., Seoul, KR;
Abstract
Beams generated from first and second laser light sources are reflected by a beam splitter to proceed toward an optical disc. The laser beams focus onto the optical disc via a selective light-transmitting part installed in front of the optical disc and an objective lens. The selective light-transmitting part is formed by an inner circular part for transmitting only the laser beam of first wavelength and a peripheral part for transmitting only the laser beam of second wavelength. The beam having transmitted through the inner circular part forms the larger beam spot on the disc while that having transmitted through the peripheral part forms the smaller beam spot, so that double beam focuses of different sizes can be formed by a single optical pickup device.