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:
May. 31, 1994
Filed:
Dec. 05, 1990
Nobuyoshi Tsuboi, Ibaraki, JP;
Yoshio Sato, Hitachi, JP;
Hiroyuki Minemura, Hitachi, JP;
Hisashi Andoh, Hitachi, JP;
Masaichi Nagai, Hitachi, JP;
Isao Ikuta, Iwaki, JP;
Yoshimi Katou, Takahagi, JP;
Yoshihito Maeda, Mito, JP;
Tatsuya Sugita, Hitachi, JP;
Yutaka Sugita, Tokorozawa, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
There is provided a compact and thin optical disk unit as a memory unit suitable for a portable computer such as a book type computer and a portable recording/reproducing apparatus. In the optical disk unit, the diameter of an objective lens is limited and a beam shaping prism, a beam splitter, a mirror and a 1/4 wavelength plate are formed into a unitary structure to make easy the optical axis adjustment of an optical head and ensure highly accurate assembling.