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:
Nov. 11, 2008

Filed:

Jun. 07, 2005
Applicants:

Tae-youn Heor, Suwon-si, KR;

Tae-yun Kim, Suwon-si, KR;

Jung-woo Hong, Suwon-si, KR;

Inventors:

Tae-youn Heor, Suwon-si, KR;

Tae-yun Kim, Suwon-si, KR;

Jung-woo Hong, Suwon-si, KR;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B 7/00 (2006.01);
U.S. Cl.
CPC ...
Abstract

A photo detector for use in an optical pickup apparatus that detects a beam reflected from the disc, and includes a substrate for transmitting one main beam and two sub beams reflected from the optical disc; a liquid crystal for refracting the two sub beams, that are transmitted through the substrate, at different refractive indexes according to the wavelength of a laser beam outputted from the laser diode; an electrode material for supplying power to the liquid crystal; a switch for adjusting the magnitude of an applied voltage to the electrode material; and a photodiode on which the main beam and the refracted sub beams while transmitting the substrate and the liquid crystal are projected, and transformed into electric signals. By refracting the beams refracted from the disc at a proper refractive index, the ±1-order beams can be projected onto the same position, irrespective of the wavelengths.


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