延展高分子分散型液晶在散射式偏光膜之應用

Abstract

傳統吸收式偏光片為液晶顯示器中主要元件之一，然而，穿透式液晶顯示器由於吸收式偏光片、濾光片、導光板…等元件吸收而光利用效率低落。近年來，非吸收式偏光片由於具有將原本應被吸收的光回收利用的特性而受到廣泛注目和研究，非吸收式偏光片的工作原理主要分為反射式和散射式兩大類，而能將光反射或散射之後回收利用。

具有極化選擇性的延展高分子分散型液晶薄膜為散射式偏光片的一種，應用於液晶顯示器中，可有效地將光散射回背光模組中並回收利用，而提升光效率，達到增亮的效果。本篇論文的主要目的便是研究延展高分子分散型液晶薄膜的光學特性，並將拉伸方向由一維單向進一步地延伸至二維徑向拉伸，製作徑向對稱偏光片。

The conventional absorbing polarizer is a key component in current LCDs. However, the optical efficiency of typical transmission type LCDs was low due to absorbing polarizer, color filter, light guide in back light module, and so on. Recently, nonabsorbing polarizers were widely noticed to recycle the light utilization. The basic concepts of nonabsorbing polarizers fall into two categories: reflecting and scattering.

The stretched PDLC film associated with polarization selectivity is a sort of scattering polarizer. With this film utilized in LCDs, the light is backscattered and recycled in the backlight module instead of being absorbed. The light efficiency was thus enhanced by polarization recycling mechanism. The purpose of this thesis was to investigate the optical properties of the stretched PDLC films. In conclusion, the fabricated film performed 50% transmittance along transmission axis and 0.06 for extinction ratio. Besides, the direction of polarization of the converted light can be controlled by varying the stretching direction of the films. The azimuthal polarizers are fabricated by change the stretching direction from linear to two-dimensional radially direction.