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:
Sep. 22, 2009
Filed:
Apr. 15, 2004
Kentarou Takeda, Ibaraki, JP;
Naoki Takahashi, Ibaraki, JP;
Kazutaka Hara, Ibaraki, JP;
Takahiro Fukuoka, Ibaraki, JP;
Kentarou Takeda, Ibaraki, JP;
Naoki Takahashi, Ibaraki, JP;
Kazutaka Hara, Ibaraki, JP;
Takahiro Fukuoka, Ibaraki, JP;
Nitto Denko Corporation, Ibaraki-shi, JP;
Abstract
An optical element of the invention comprises at least three laminated circular-polarization-type-reflection polarizers (a) whose wavelength bands for selective reflection of polarized light overlap one another; a layer (b) which is placed between at least a pair of the circular-polarization-type-reflection polarizers (a) and has a front retardation of substantially zero (in the normal direction) and a retardation of at least λ/8 with respect to incident light inclined by at least 30° relative to the normal direction; and a layer (b) which is placed between at least another pair of the circular-polarization-type-reflection polarizers (a) and has a front retardation of substantially zero (in the normal direction) and a retardation of at most λ/2 with respect to incident light inclined by 60° relative to the normal direction. The optical element condenses or collimates incident light from a light source and can control transmission of light at large incident angles relative to the normal direction, increase front brightness and reduce coloration.