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. 31, 1991
Filed:
Dec. 24, 1987
Hiroshi Yoshimatsu, Tokyo, JP;
Sony Corporation, Tokyo, JP;
Abstract
An optical pick-up apparatus comprises a light beam generating source, an objective lens for causing a light beam from the light beam generating source to impinge upon a record medium and receiving a reflected light beam from the record medium, a composite prism constituted by a glass prism element, a crystal prism element and a multi-layer of dielectric material provided between the glass and crystal prism elements, which are bonded together, and so disposed that the light beam from the beam generating source and the reflected light beam from the objective lens enter into the glass prism element through respective different optical paths, the light beam from the beam generating source is directed to the objective lens after passing through the glass prism element and at least two light beams obtained based on the reflected light beam from the objective lens emerge from the crystal prism element, and a photodetecting unit for detecting separately the light beams emerging from the crystal prism element of the composite prism.