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:
Jan. 29, 2008

Filed:

Nov. 15, 2002
Applicants:

Tae-kyung Kim, Seoul, KR;

Young-man Ahn, Suwon-si, KR;

Chong-sam Chung, Suwon-si, KR;

Hae-jung Suh, Hwaseong-si, KR;

Jin-kyung Lee, Suwon-si, KR;

Jong-bae Kim, Seoul, KR;

Inventors:

Tae-kyung Kim, Seoul, KR;

Young-man Ahn, Suwon-si, KR;

Chong-sam Chung, Suwon-si, KR;

Hae-jung Suh, Hwaseong-si, KR;

Jin-kyung Lee, Suwon-si, KR;

Jong-bae Kim, Seoul, KR;

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B 7/135 (2006.01);
U.S. Cl.
CPC ...
Abstract

A compatible optical pickup includes an optical disc, an objective lens, a diffractive device, and a divergent lens. The optical unit emits a short wavelength light beam corresponding to a high density optical disc and a long wavelength light beam corresponding to a low density optical disc. The objective lens forms a light spot on the high density optical disc and the low density optical disc and the diffractive device diffracts the short wavelength light beam to correct chromatism according to a change in a wavelength of the short wavelength light beam. The divergent lens refracts the long wavelength light beam toward the objective lens to increase a working distance with respect to the low density optical disc.


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