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. 15, 1996
Filed:
Feb. 07, 1995
Junichi Nakano, Hino, JP;
Nobuo Miyairi, Fujinomachi, JP;
Shohei Kobayashi, Hachioji, JP;
Akihiko Yoshizawa, Tsukuimachi, JP;
Olympus Optical Co., Ltd., Tokyo, JP;
Abstract
The present invention is directed to an apparatus using an integrated type pickup as an optical head for writing and reading optical information and capabling of writing data at high speeds. The apparatus includes a laser diode having an active layer at its intermediate position and having one area side held over a surface of a semiconductor substrate with an insulating layer interposed between the semiconductor substrate and the laser diode relative to the active layer. The laser diode has two areas with the active layer as a boundary and a constant potential is applied from a power supply to the insulating layer side of the laser diode and a transistor (laser diode drive unit) is provided to apply a modulation signal to the other area of the laser diode so that the laser diode is driven to modulate its output. By doing so, a constant potential is maintained at the semiconductor substrate and at the insulating layer's side of the laser diode and the modulation signal is applied to the other area side of the laser diode. When a drive current of the laser diode is varied by the modulation signal, a voltage variation occurs only on the other area side of the laser diode so that a high-frequency drive current, if flowing through the insulating layer side, is small and hence the laser diode has its output to be modulated effectively.