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:
Apr. 24, 2001
Filed:
Mar. 01, 1999
Takashi Nagano, Hamamatsu, JP;
Yamaha Corporation, Hamamatsu, JP;
Abstract
In an optical disk recording device for irradiating a recording light beam onto an optical disk to form pits having lengths ranging from 3Ts to 11Ts (where T represents a length of a unit time period in a longitudinal direction of a pit track), a sample and hold circuit samples and holds levels of a reflection signal, representative of a reflection of the recording light beam from the optical disk, for a predetermined time period between points of 1T and 3Ts after the start of a rising edge of the reflection signal. Comparator circuit makes a comparison between the sampled and held levels of the reflection signal and a predetermined reference level. Automatic laser power control circuit controls the power of the recording light beam on the basis of a result of the comparison by the comparator circuit. With such an arrangement, the recording power of the light beam can be controlled promptly with increased accuracy.