向列型液晶4-n-pentyl-4'-cyanobiphenyl 在具微溝槽結構的高分子膜表面上之排列行為研究

Abstract

配向膜在液晶顯示器中十分的重要，配向膜的作用是使液晶分子朝單一方向排列，以發揮液晶的光電性質。工業上是利用定向摩擦法製備配向膜，但此法存在著許多的缺點，像是在摩擦的過程中會產生靜電力或是碎屑，都會造成液晶顯示器上的缺陷。 在本實驗當中，利用軟式印章壓印法來製作高分子微溝槽表面，由於溝槽效應的作用，液晶會順著溝槽的方向排列以達到配向的效果，此種方式不但製作方法簡單，也可避免靜電和碎屑產生的困擾。使用的高分子材料，包括Nylon66、PET、PVA、PS、PC、PMMA、PDMS，都能夠成功的製作出大面積的微溝槽表面，而隨著高分子結構的不同，配向性也不盡相同。其中結晶性高分子皆可有很好的配向性；而非結晶性高分子，則會在某些溝槽規格下有著不好的配向性。 除此之外，PDMS原本為用來壓印高分子配向膜的軟印章材料，但由於其本身具備有極佳的彈性，因此若利用PDMS作為配向膜材料，可應用於可撓性面板中。PDMS本身為疏水性的材質，但利用電漿處理及自聚性分子的鍵結，則可調控出不同親疏水性的表面。

Alignment film is a very important part in liquid crystal display technology. It could make liquid crystal to arrange in order and then to properly perform the electro-optical properties of liquid crystal. Nowadays, rubbing is the most common method to fabricate alignment film. But it still exists a lot of drawbacks, such as static electricity and contaminants which deteriorate the quality of LCD. In this work, the soft embossing method is proposed to fabricate grating structure on polymer surfaces. By groove effect, liquid crystal prefer to align parallel to the direction of grating. This method provides a convenient and rapid way to make alignment film. The polymers used in this work include Nylon66, PET, PVA, PS, PC, PMMA, and PDMS. All of them could successfully fabricate large area of grating structure. The polymer films’ alignment ability relate to polymers’ properties and structure. The film made from crystalline polymers could get excellent alignment ability. Amorphous polymers’ alignment ability most are not good enough. Moreover, I use PDMS as stamps in this work, but we could also fabricate alignment film by PDMS. Because of its elasticity, the PDMS film could apply on flexible display.