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. 26, 2002
Filed:
Apr. 25, 1997
Osamu Itoh, Hitachi, JP;
Shinichi Komura, Hitachi, JP;
Ikuo Hiyama, Hitachi, JP;
Shoichi Hirota, Hitachi, JP;
Masaya Adachi, Hitachi, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A liquid crystal display featuring excellent visibility with both good brightness and a high contrast ratio uses a projection optical system in which a polarizing plate, a first phase plate and a second phase plate in which the retardation of each of the phase plates and a gradient of wavelength dispersion of the retardation can be freely set, a liquid crystal layer, and a reflection plate are arranged in parallel and a transmitted light is reflected by the reflection plate. A gradient of one of the phase plates is set to an extremely steep gradient, a gradient of the other phase plate is set to an extremely flat gradient, and the wavelength dispersion of a retardation composite value obtained from the liquid crystal layer and the two phase plates is approximated to a retardation curve expressed by a relational expression of (0.25+0.5n)&lgr;, where (n) is an integer and &lgr; is a wavelength (nm) of the transmitted light.