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. 13, 2004
Filed:
May. 14, 2002
Hitachi, Ltd., Tokyo, JP;
Abstract
An information recording/reproducing apparatus includes a semiconductor laser, a laser driver which drives the semiconductor laser, an optical system which focuses light emitted from the semiconductor laser on an information recording medium, a photodetector which detects light reflected from the information recording medium, and outputs a reflection light signal, a modulation circuit which modulates information in accordance with a predetermined rule, and outputs a binary signal representing the modulated information, and a calculation/control circuit which controls the modulation circuit. The laser driver includes a delay circuit, and receives the binary signal, generates a recording current signal corresponding to the binary signal through the delay circuit, and transmits an output of the delay circuit to the calculation/control circuit as a monitor signal. The calculation/control circuit generates a timing signal for sampling and holding the reflection light signal based on the monitor signal.