Cell with a double liquid crystal layer using the electrically controlled birefringence effect and process for producing a uniaxial medium with negative optical anisotropy usable in said cell
US4813770A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 17, 1987 |
| Grant date | Mar 21, 1989 |
| Priority date | — |
| Expiry date | Feb 17, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/1393
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Cell with a double liquid crystal layer using the electrically controlled birefringence effect and process for producing a negative optical anisotropy uniaxial material usable in said cell. The cell can comprise two crossed rectilinear polarizers, three glass plates provided with transparent electrodes and placed between said polarizers, two liquid crystal layers between the plates and, between a plate and a polarizer, a sheet of the medium, whose extraordinary axis is perpendicular to the plates. This sheet can be obtained by heating a thermoplastic polymer up to the isotropic state, under a uniform pressure on the polarizers, cooling and eliminating the pressure. The cell is designed in such a way that the molecules of the respective layers tilt in two directions forming the same angle with the homeotropy direction, when an exciting voltage is applied between the electrodes, said directions, viewed in projection on a plate, also being opposite in the main observation plane. Application to the production of television screens.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.