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:
Mar. 20, 2001
Filed:
Aug. 31, 1998
Hitachi, Ltd., Tokyo, JP;
Abstract
An objective is to provide a technique capable of reproducing high-density recorded fine recording marks with excellent high output and excellent quality. To this end, with the present invention, light,is irradiated intermittently to an optical recording medium changeable in optical nature due to irradiation of light, permitting a differential amplifier,to perform differential processing of a signal as obtained by detection of reflection light rays at at least two time points during irradiation of the intermittent light to thereby obtain a reproduction signal. It is thus possible to effectively detect only a signal component of certain part whereat the reflection light is changed due to light irradiation during irradiation of the intermittent light, which in turn enables reproduction of fine record information with increased resolution while enabling suppression of those components other than the change component. This makes it possible to obtain a reproduction signal with good quality.