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:
Mar. 25, 1997
Filed:
Apr. 14, 1995
Isao Hoshino, Yokohama, JP;
Shoko Wachi, Tokyo, JP;
Yoshinori Honguh, Yokohama, JP;
Masahiko Tanaka, Yokohama, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
An optical head device adapted to be optically coupled to an optical disk includes a light-source laser and an objective lens optically coupled thereto. This lens receives an output light of the light source, and causes it to be projected onto the optical disk to form a focused spot thereon. Photodetectors which are arranged near the light-source laser are optically coupled to the lens in one optical path so that they are responsive to a light component which is reflected from the optical disk toward the photodetectors by way of the objective lens. A beam-shaping prism is located between the lens and a group of the light source and the photodetectors in the optical path. When the laser output light travels toward the lens, the prism reshapes the light into a predetermined isotropic beam profile. When the reflected light from the optical disk propagates reversely along the same optical path to enter the beam-shaping prism, this prism permits such an incident light to pass through itself toward the photodetectors.