彩色高分子分散液晶薄膜之研究

Abstract

高分子分散型液晶(Polymer-Dispersed Liquid Crystal , PDLC)為近幾年所發展出的光電顯示元件，相對於傳統液晶顯示器，PDLC有著不需偏光片、不需配向、製作容易及可使用於軟性基板上的優點，可以應用在光開關、投影顯示及電子書…等。 PDLC的光電特性中，反應時間、驅動電壓、對比度等，會直接影響其應用上的表現，本論文採取□雜二色性染料來進行對比度的提升。使用的條件：液晶(E7)及高分子(PVA)混合比為35:65，以0.5%~1.5%微量□雜二色性染料，使用均質機將上述材料混合均勻，並以自動塗佈機分別製作樣本。完成樣本後，使用光偵測量測系統測量光電特性，並以偏光顯微鏡觀察樣本。 實驗發現，與未□雜的樣本相比較下，M-483(藍色)二色性染料□雜濃度1%的樣本表現最佳，其對比度提升了11%，有明顯的改善。在觀察樣本後發現，□雜奈米微粒(Ludox) 液晶滴形狀及分佈比較均勻，提供PDLC薄膜初期達到良好之霧化效果，以阻絕光線。

In this study , we developed a PDLC cell as a electrical switchable optical device . Comparing with conventional LC displays, PDLCs need no polarizer , alignment , can be applied in flexible display and are easier for production . PDLC cells can be used for include light shutters, projecting displays, and e-books applications .

Of a PDLC display , it’s important to improve it’s electro-optical properties Such as response time , driving voltage , and the contrast ratio . All these parameters play important roles in improving the performance of the PDLCs.

A guest-host (GH) LC was prepared by mixing E7 and selectively dichroic dye together . GHLC was mixed with PVA with certain ratio and followed by homogenizing to from the emulsions . The emulsions were coated , fabricated as switchable devices under different conditions . The electro-optical properties of the obtained PDLC cells were investigated .

In this study , an optimized LC composition was made to enhance the contrast ratio. With the nano-particle assistance, the PDLC film can offer very good light scattering performance by increasing the LC droplet size uniformity.