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:
Feb. 11, 1992
Filed:
May. 11, 1989
Isamu Moriwaki, Hiratsuka, JP;
Hiroyuki Kiguchi, Atsugi, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
An optical pickup apparatus in which a laser beam reflected from an optical memory medium is separated and incident to a light-receiving element having a plurality of divided light-receiving faces and a focusing error signal is formed on the basis of a difference signal provided by a predetermined combination of light-receiving signals outputted from the respective light-receiving faces of the light-receiving element, comprises a bias signal forming device for forming a bias signal in accordance with a reflectance ratio of the optical memory medium based on a sum of the light-receiving signals outputted from the respective light-receiving faces of the light-receiving element; and a device for superimposing the bias signal on the focusing error signal in an accessing stand-by state with respect to the optical memory medium.