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:
Apr. 18, 1995
Filed:
Jan. 22, 1993
Uruo Kobayashi, Tokyo, JP;
Yoji Oki, Yokohama, JP;
Nobuo Matsui, Yokohama, JP;
Yoshinori Go, Yokohama, JP;
Stanley Electric Co., Ltd., Tokyo, JP;
Abstract
A planar illuminating device, comprising a light-transmitting plate made of a transparent material and having opposite side edges and opposing front and rear faces, two sources of light each arranged adjacent to one of the side edges of the plate, a reflector arranged behind the plate rear face and reflecting rays of light from the plate to the front face of the plate, a light diffuser arranged in front of the plate and diffusing rays of light from the plate. The device comprises a reflecting finish applied directly to the rear face of the plate. A reflecting surface of the reflecting finish faces substantially in the direction of the front face of the plate. The reflectance of part of the reflecting finish depends on the distance of that part from either of the two sources of light. The device further comprises parallel prismatic cuts along the front face of the plate. The longitudinal axes of the prismatic cuts are substantially parallel to rays of light passing from the sources of light through the plate. A combination of the reflecting finish and the reflector increases the surface illuminance and the uniformity in the surface illuminance of the planar illuminating device.