Normally white twisted nematic LCD with positive and negative retarders
US5739881A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 3, 1997 |
| Grant date | Apr 14, 1998 |
| Priority date | — |
| Expiry date | Apr 3, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F2413/14
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A normally white twisted nematic liquid crystal display is provided for outputting improved viewing characteristics which are defined by high contrast ratios and reduced inversion. The display includes both positive and negative retardation films, the negative films being defined by n.sub.x =n.sub.y >n.sub.z where the "z" direction is substantially perpendicular to the film plane and the "x" and "y" directions are substantially parallel to the film plane. According to certain embodiments, a pair of positive and a pair of negative retardation films are provided such that the two positive retarders sandwich both the liquid crystal layer and the negative retarders therebetween. By providing the positive and negative retarders with specific retardation values and/or ratios, improved viewing characteristics are provided.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.