English Abstract

Recent Trends in the Retardation Films

Takashi SATO
Precision Optics, ZEON Corporation, Kawasaki-ku, Kawasaki, Kanagawa, Japan
Nippon Gomu Kyokaishi,(2011),84(8),242-249 General Review in Japanese

Liquid crystal displayiLCDj contains many plastic films. A retardation film is one of the optical films which compensates for the loss of color contrast and the black level in LCD. Many retardation films have been developed so far to improve the optical properties in many display modes, for example twisted nematic LCD, super twisted nematic LCD, vertical alignment, in-plane switching, and so on.
This article shows the compensation mechanism and manufacturing processes of the retardation films. LCD works under polarized light. The retardation films regulate the polarized light which is disturbed by the liquid crystal and polarizer.
The manufacturing processes have been developed from conventional film manufacturing processes to high performance processes. Those processes can produce the retardation films with wide widths and with uniform optical properties and thicknesses.
A new stretching process has been developed. The process enabled to control optical axis in film surface. The oblique stretching process gives an advantage to roll-to-roll process because of producing low-cost retardation films.

Keywords: Retardation Film, Liquid Crystal Display, Roll-to-roll Process