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. 14, 2000
Filed:
Mar. 15, 1999
Keiji Iimura, Itabashi-ku Tokyo, 175-0092, JP;
Other;
Abstract
A flat light source i.e. a surface light source and a passive display using the same are disclosed, capable of making optimal light leakage with uniform brightness across the entire area of its large flat surface. The flat light source comprises a first light transmission means for illumination with relatively high refractive index, a second light transmission means for bypass light guide including at least one light guide having relatively high refractive index and a light coupling means making light coupling between the both first and light transmission means for changing direction of light rays, wherein the light rays output from the second light transmission means are changed in direction in order to input into the first light transmission means. A plurality of optical fibers may be used as the light-guides for light bypassing, in which they are aligned at least in one line in the second light transmission means, by which almost all incident light rays can be transmitted along entire length of the second light transmission means with minimized loss. The light coupling means may be composed of at least one optical element with high reflactive index, having a cross-sectional shape selected from a group of a trapezoidal, a triangular, a half-circular and a 'U' shape. The first light transmission means may have a first terminal surface and the second light transmission means may have a second terminal surface. A common i.e. single light generating means may be provided in order to project light rays to the first terminal surface and/or the second light transmission means.