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:
Jun. 07, 1988
Filed:
Mar. 05, 1986
Kunio Yamamiya, Sagamihara, JP;
Masaharu Sakamoto, Tokyo, JP;
Olympus Optical Co., Ltd., Tokyo, JP;
Abstract
A device for detecting the abnormality of an optical pick-up head has a laser diode for emitting a light beam through an optical system to a reference reflective region formed at a predetermined portion of an optical disk, a photosensor for receiving a reflected light from the reflective region through the optical system, and a photosensor for detecting directly the light amount of the laser diode. The difference or a ratio of the detection signals of the photosensors is obtained, and the difference or the ratio is compared with a predetermined value. When the compared result exceeds a predetermined value, the result is decided to be an abnormality of the pick-up head.