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:
Jan. 28, 1992
Filed:
Aug. 23, 1990
Fumiaki Henmi, Kanagawa, JP;
Koichi Nakajima, Kanagawa, JP;
Sony Corporation, Tokyo, JP;
Abstract
A cutting apparatus is provided, in which a recording laser beam from a laser light source is ON/OFF-modulated by an optical modulating device on the basis of a square output signal in which a video FM wave signal is pulse width modulated by an audio FM wave signal thereby to form exposure pits on a master disc. This cutting apparatus includes a photodetector for receiving one portion of the recording laser beam irradiated on the master disc from the laser light source or a photodetector for receiving a reflected light of the recording laser beam irradiated on the master disc from the laser light source and which is reflected on the master disc. A detected output signal from the photodetector is supplied through a low-pass filter to a control circuit which controls an intensity of an output laser beam from the laser light source, and an offset of a source system line is adjusted so that a secondary higher harmonic component of a main carrier in the detected output from the photodetector is minimized.