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:
Jul. 16, 1996
Filed:
Apr. 04, 1995
Shigeaki Wachi, Kanagawa, JP;
Sony Corporation, Tokyo, JP;
Abstract
An optical recording medium on which a data signal is formed comprises an area A of recording tracks for recording a data signal between pairs of grooves Gr and a d.c. offset cancel area B for canceling d.c. offset by the push-pull system, which serves as a predetermined area. In the d.c. offset cancel area B, no grove Gr is formed, and grooves are formed at the recording track center positions Tc. The groove at the recording track center position Tc is caused to have the same width and depth as those of the groove Gr. In carrying out recording/reproduction of a data signal by using this optical recording medium, a return light from the optical recording medium is detected by a bisected detector. A difference signal between outputs from the detector is determined by an amplifier. In accordance with an output signal of a sample-hold signal supply unit, first and second sample-hold units respectively hold signals having output phases different from each other by 180 degrees. An adder adds these signals to take out only a d.c. fluctuation component to eliminate the d.c. fluctuation component superimposed on a tracking error signal at a d.c. offset eliminating unit.