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:
Aug. 11, 1998
Filed:
Jun. 11, 1996
Masahiko Ishimaru, Odawara, JP;
Tsuyoshi Toda, Kodaira, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A recording/reproducing apparatus includes a laser for generating laser light to be used for recording/reproducing information onto/from a recording medium, a beam splitter for separating a luminous flux for a monitor, a photodetector for receiving the luminous flux, a power control circuit for keeping an average output of the laser at a predetermined value, a high-frequency adding circuit for applying high-frequency modulation to the laser, and a controller for altering the degree of modulation of the high-frequency modulation. When the average output of the laser is kept constant by the power control circuit, the degree of modulation conducted by the high-frequency adding circuit is altered, the light emitting power (bottom power) subjected to no high-frequency modulation being thus controlled.