Process for producing phase retarder film
US5474731A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 12, 1994 |
| Grant date | Dec 12, 1995 |
| Priority date | — |
| Expiry date | Apr 12, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S264/71
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A process for continuously producing a phase retarder film or sheet comprising continuously supplying a stretched thermoplastic resin film or sheet to a heating zone in parallel with the stretching direction of the film or sheet and heating the film or sheet to a temperature not lower than the glass transition temperature of the resin while applying pressure to the surface of the film or sheet passing through the heating zone, thereby continuously subjecting the film or sheet to thermal relaxation while suppressing the expansion of the film or sheet in a direction parallel to the surface of the film or sheet and perpendicular to the stretching axis. According to the present invention, a phase retarder film or sheet having a low angular dependence of retardation can be produced continuously. By using the phase retarder film(s) or sheet(s) thus obtained as optical compensator(s), the viewing angle characteristics of liquid crystal display devices can remarkably be improved.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.