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. 05, 1988
Filed:
Dec. 30, 1985
Shozi Yoshikawa, Tokyo, JP;
Olympus Optical Co., Ltd., Tokyo, JP;
Abstract
In a stabilized laser device of an optical recording/reproduction apparatus, in the reproduction mode, a laser beam of reproduction level is radiated on an optical disk, and data is read from the disk in the form of the light reflected from the disk. In the recording mode, a laser beam of the recording level (several times higher than the reproduction level) is radiated on the disk to form pits in the disk surface. The device has a semiconductor laser, a reference voltage generation source for generating reference values of the reproduction and recording levels, and a photodiode for photoelectrically converting laser light from the semiconductor laser so as to generate a detection signal a source of drive signals is provided for generating a first drive signal corresponding to the difference between the reference value of the recording level and the detection signal from the photodiode, and a second drive signal corresponding to the difference between the sum of reference values of the recording and reproduction levels and the detection signal from the photodiode. A switch supplies, in the reproduction mode, the first drive signal to the semiconductor laser and, in the recording mode, supplies one of the first drive signal and the sum of first and second drive signals in accordance with recording data.