Utilization of dyes for liquid crystal displays
US4137193A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 23, 1977 |
| Grant date | Jan 30, 1979 |
| Priority date | — |
| Expiry date | Jun 23, 1997 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09K19/601
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
In a cholesteric guest-host liquid crystal composition having a positive dielectric anisotropy and consisting of a nematic host component with a dye incorporated as a guest component therein and an optically active (cholesteric) component, the improvement consisting of a substantially stable and water insoluble azo dye guest component having a pleochroic ratio a.sub.1 /a.sub.2 of at least 6.5 and an absorption maximum in the range of from 350 to 700 nm, said azo dye being a compound of the formula (1) EQU X -- A -- N .dbd. N -- B -- Y (I) wherein A is selected from the group consisting of 1,4-phenylene, 2-hydroxy-1,4-naphthylene and 2-hydroxy-8-amino-1,4-naphthylene; B is selected from the group consisting of 1,4-phenylene, 1,5-naphthylene and 5-substituted benzothiazo-(1,3)-2-yl; X is selected from the group consisting of nitro, nitrile, dimethylamino, di(hydroxyethyl)-amino, phenyl and straight chain C.sub.1 -C.sub.10 alkyl, and Y is a monovalent organic radical that does not promote water solubility in the dye molecule.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.