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:
Sep. 08, 1998
Filed:
Jul. 17, 1997
Toshiya Murakami, Kanagawa, JP;
Tsukasa Wadamori, Kagoshima, JP;
Sony Corporation, , JP;
Abstract
A laser power control circuit for controlling the laser power is provided in an automatic power control circuit of an optical disc device, an amplitude of an RF signal is examined by the LPC circuit, a control voltage to be applied to the APC circuit is generated, and feedback is applied to control the laser power and stabilize the RF signal level. By this, the reproduction can be stably carried out by even discs having different reflection rates, an improvement of the reproduction capability can be achieved, and a lowering of the optical output of the laser diode accompanied with aging and the lowering of the reproduction capability accompanied with the lowering of the optical output due to dust adhered to the pick-up can be prevented. Further, the laser power per se is controlled, so there is no effect on the band of the RF amplifier.