Liquid crystal display
US4252417A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 13, 1979 |
| Grant date | Feb 24, 1981 |
| Priority date | — |
| Expiry date | Jun 13, 1999 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09K19/60
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
A liquid crystal display is described for displaying dark signs on a light background in accordance with the guest-host principle without polarizers. The display includes parallel plates the insides of which are provided with an orientation layer which produces a homoeotropic orientation in an adjacent liquid crystal mixture. The liquid crystal mixture is formed primarily of a nematic liquid crystal having a high negative dielectric anisotropy and, secondarily, of an optically active substance. The proportion of the optically active substance is smaller than the quantity which would cause a spontaneous formation of a twisted structure in the liquid crystal mixture in the field-free state. The liquid crystal mixture is thus homoeotropically oriented and transparent throughout in the field-free regions, and is planar-cholesteric and absorbing in the activated regions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.