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:
Dec. 20, 2005
Filed:
Jul. 02, 2001
Byung-in MA, Suwon-si, KR;
In-sik Park, Suwon-si, KR;
Chong-sam Chung, Suwon-si, KR;
Jin-hoon Jeon, Suwon-si, KR;
Tae-yong Doh, Suwon-si, KR;
Byoung-ho Choi, Suwon-si, KR;
Byung-in Ma, Suwon-si, KR;
In-sik Park, Suwon-si, KR;
Chong-sam Chung, Suwon-si, KR;
Jin-hoon Jeon, Suwon-si, KR;
Tae-yong Doh, Suwon-si, KR;
Byoung-ho Choi, Suwon-si, KR;
Samsung Electronics Co., Ltd., Suwon-si, KR;
Abstract
An apparatus for and a method of detecting a defocus error signal. First, second and third light receiving regions of a photodetector are arranged in a radial direction of a recording medium to independently perform photoelectric conversion with respect to incident light which is reflected/diffracted by the recording medium. A subtractor subtracts a sum signal of detection signals from the first and third light receiving regions and a detection signal of the second light receiving region to output a defocus error signal, to detect defocus and/or a change in thickness of the recording medium. The defocus error signal and a push-pull tracking error signal are compared in a state in which a predetermined amount of defocus is applied to a light spot to detect a seek direction of the recording medium having a land/groove structure.