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:
Feb. 15, 2000
Filed:
Nov. 05, 1998
Nitto Denko Corporation, Osaka, JP;
Abstract
A wavelength plate which shows little undesirable retardation in a specific wavelength range while substantially maintaining the function of 1/2 wavelength plate or 1/4 wavelength plate over the entire visible light range and a circular polarizing plate which shows little reflection at the interface and exhibits an anti-reflection effect over a wide wavelength range and an excellent thermal stability. A laminated wavelength plate comprising a plurality of oriented films giving a retardation having a wavelength half that of monochromatic light laminated with their optical axes crossing each other, wherein the dependence of the birefringence differences .DELTA.n.sub.1 and .DELTA.n.sub.2 of said oriented films on wavelength each satisfy the relationship .DELTA.n.sub.1 /.DELTA.n.sub.2 <1.05 based on light having wavelength of 400 nm (.DELTA.n.sub.1) and 550 nm (.DELTA.n.sub.2), a laminated wavelength plate comprising a plurality of oriented films laminated with their optical axes crossing each other, the dependence of the birefringence differences .DELTA.n.sub.1 and .DELTA.n.sub.2 of said oriented films on wavelength each satisfying the relationship .DELTA.n.sub.1 /.DELTA.n.sub.2 <1.05 based on light having wavelength of 400 nm (.DELTA.n.sub.1) and 550 nm (.DELTA.n.sub.2), wherein the oriented films used are those giving a retardation of 1/2 wavelength with respect to monochromatic light and those giving a retardation of 1/4 wavelength with respect to monochromatic light in combination, a circular polarizing plate comprising a laminate of the the laminated wavelength plate having a 1/4 wavelength plate and a polarizing plate, and a liquid crystal display comprising the circular polarizing plate.