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:
Nov. 04, 2003
Filed:
Jan. 02, 2002
Tatsuo Ito, Osaka, JP;
Shin-ichi Kadowaki, Sanda, JP;
Tomotada Kamei, Neyagawa, JP;
Hiroaki Yamamoto, Hyogo, JP;
Yoshiaki Komma, Hirakata, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
To provide a laser driving apparatus which is inexpensive and has high reliability in spite of using a plurality of light sources, since a multi-wavelength light source is required for treating different kinds of optical disks such as CD, DVD or the like. In a two-wavelength LD apparatus including: a semiconductor laser ; a semiconductor laser ; and a photo detector , optical outputs of the semiconductor lasers are controlled by APC circuits on the basis of respective voltage values of variable resistors connected in series to the photo detector . Alternatively, in the two-wavelength LD apparatus including: the semiconductor laser ; the semiconductor laser ; and the photo detector , the optical outputs of the semiconductor are controlled by the APC circuits on the basis of respective intermediate potentials of variable resistors connected in parallel with the photo detector