利用摻雜染料聚合物穩定藍相液晶之不需偏光片的光電開關

Abstract

本論文主要是利用摻雜染料之聚合物穩定藍相液晶(DDPSBP-LC)實現不需偏光片之光電開關。此光電開關原理為：未加電壓時，DDPSBP-LC呈現暗態，主要是因為DDPSBP-LC具週期性結構的布拉格反射、染料分子對各個方向偏振光的強吸收及藍相液晶和聚合物網絡間折射率不匹配的強散射所造成。當施加電壓於DDPSBP-LC，DDPSBP-LC呈現亮態，因為液晶分子局部解旋而平行電場排列，因而造成弱散射及無布拉格反射，同時染料分子平行液晶分子，亦造成弱吸收，此DDPSBP-LC之亮暗態為偏振無關。相關電光特性、偏振相關性、溫度效應等也在此論文中討論。利用DDPSBP-LC之光電開關具有不需偏光片、不需配向層、簡單電極設計、反射率高、快速響應之特點。未來還可以將DDPSBP-LC應用於其他光電元件，如汽車後照鏡所用的防眩目鏡、3D立體顯示的快門眼鏡等。

We successfully demonstrated a polarizer-free electro-optical switch using dye-doped polymer stabilized blue phase liquid crystal, or DDPSBP-LC. The operating principle is: at voltage-off state, the dye molecules and liquid crystal form the structure of the double twist cylinders. As a result, the DDPSBP-LC is in dark state due to the combination of Bragg reflection, scattering and light absorption. At the voltage-on state, the blue phase structure is unwound locally. The DDPSBP-LC is then in bright state because of the small light absorption only. The bright state and dark state of DDPSBP-LC is polarizer-free. We measured the electro-optics properties, the polarization dependency, the temperature effect of DDPSBP-LC. DDPSBP-LC electro-optical switch have the advantage of polarizer-free, alignment-layer free, high reflection, simple electrode design and fast response time. The other electro-optical applications of DDPSBP-LC are dimming mirror, 3D shutter glasses, etc.