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:
Jun. 14, 2005
Filed:
Jul. 14, 2003
Takuro Sugiura, Fukushima-ken, JP;
Takuro Sugiura, Fukushima-ken, JP;
Alps Electric Co., Ltd., Tokyo, JP;
Abstract
An illumination device includes a light source composed of a light emitting element and an intermediate light guide, and a light guide plate that receives light from the light source through a light incident face and that emits the light propagating therein from an emergent surface. A reflecting surface of the light guide plate has a plurality of prism grooves formed in stripes in plan view, each prism groove having a gently inclined face and a sharply inclined face inclined more sharply than the gently inclined face. A θ-coefficient, which is the product of the number of the sharply inclined faces per unit length of the light guide plate, and the length of the sharply inclined faces, is increased away from the light source in the light guide plate.