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:
Dec. 26, 1989
Filed:
Dec. 11, 1987
Toyoaki Takeuchi, Ina, JP;
Yoshiaki Ikeda, Hachioji, JP;
Olympus Optical Co., Ltd., Tokyo, JP;
Abstract
A focused light beam is projected upon an optical recording medium through an optical system in an optical pickup, and a light reflected from the recording medium is received to detect a focus error signal and a tracking error signal. Further, the focus control and the tracking control are both achieved through a servo feedback loop in response to the detected focus and tracking error signals. In this optical information recording and reproducing system, track formats are provided from which lights of different intensities are reflected, the track formats are discriminated by a projection position detecting circuit, and the focusing and tracking operations are controlled by selectively adjusting the gain of the servo feedback system according to the detected track format, so that the control operation is stable in recording or reproducing information data to or from a recording medium of a high density type, in particular.