Patent · US Expired

Process for the production of plastic films having improved optical properties

US4614634A · kind A · utility

5Cited by

16References

6Claims

0Family size

Assignee

BAYER HEALTHCARE LLC · DE

Inventors

Hans-Leo Weber · Eschenried, DE
Uwe Claussen · Leverkusen, DE
Hellmut Hannes · Beedenbostel, DE

Key dates

Filing date	Dec 18, 1984
Grant date	Sep 30, 1986
Priority date	—
Expiry date	Dec 18, 2004

Classification

Technology area (CPC C)Chemistry; Metallurgy
CPC primaryC08J2427/04
WIPO fieldOther special machines
WIPO sectorMechanical engineering

Abstract

An optically virtually isotropic plastic film, in particular for use in liquid crystal displays, can be produced by a method in which first an optically uniaxial birefringent plastic film is produced by casting or extrusion, and then irreversible molecular reorientation is produced in layers of the film close to the surface by heating or by immersion in a solvent or swelling agent. This reoriented structure is retained after cooling or drying of the film, and results in the birefringence (anisotropy) initially present being eliminated or compensated.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.