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:
Aug. 25, 1998
Filed:
Apr. 02, 1997
Hiroshi Kojima, Tokyo-To, JP;
Nobuo Naito, Tokyo-To, JP;
Dai Nippon Printing Co., Ltd., Tokyo-To, JP;
Abstract
A lens film provided in front of a light guide plate of a surface illuminant device comprises a base film, and a plurality of triangular parallel prisms formed in a two-dimensional arrangement on one surface of the base film integrally with the latter to form an exit surface. Each prism has a cross section of the shape of a isosceles triangle. The shape of the triangular prisms meets conditions represented by: ##EQU1## 0.5.ltoreq.R.ltoreq.1.0 where .theta.1 is a peak exit angle at which a direction, in which most part of light leaving an exit surface of a light guide plate toward the lens film travels, is inclined to a normal to an entrance surface of the lens film, .theta..sub.2 is an apex angle of the triangular prisms, and n is refractive index of the lens film. The lens film deflects incoming light so that most part of the light leaving the lens film travels in a direction substantially parallel to a normal to its imaginary exit surface, and serves to increase the head-on luminance.