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:
Oct. 05, 1999
Filed:
Feb. 13, 1997
Matsushita Electric Industrial Co., Ltd., Osaka-fu, JP;
Abstract
In an optical recording and reproducing apparatus, two light sources such as a laser diode of different wavelengths from each other are provided, and photosensors receive the light emitted by the light sources and reflected by the optical recording medium. Before recording or reproduction is started, the type of optical recording medium having a different wavelength dependent reflectance is discriminated. Because two wavelengths are used, the difference of the outputs is large, and the type of the optical recording medium is discriminated reliably according to the outputs of the photosensors. Then, the operation of the apparatus is stabilized according to the type of the optical recording medium by optimizing the laser power, the gain of the controller, the revolution number of the medium or the like.