光敏自组装单层膜用于液晶光控取向的研究

用丁二酸酐和7-羟基香豆素合成了含有脂肪族羧酸基团的光敏化合物，利用脱水反应使它在玻璃(或石英)基板表面形成自组装单层膜。用偏振紫外光照射光敏性自组装膜，与光矢量方向匹配的香豆素基团发生[2 2]周环反应，反应产物沿辐照光的偏振方向分布，形成表面张力各向异性的薄膜。用它作为向列相液晶取向膜制成平行液晶器件，在偏光显微镜下观察，发现取得了均一、稳定的取向效果。并且该取向膜有良好的热稳定性。     

基于光敏自组装多层膜的液晶光控取向膜

采用layer-by-layer(LBL)的方法，将基板依次在具有光敏双键的季铵盐水溶液和聚乙烯基苯磺酸钠水溶液中浸泡，石英基板表面形成了自组装多层沉积膜。经线性偏振紫外光辐照后，LBL多层膜表现出明显的紫外吸收各向异性。将两片带有各向异性薄膜的基板做成平行液晶器件。在正交的偏光显微镜下观察，发现取得均一、稳定的取向效果。该种光控取向膜有望用作LCoS微显示的取向层。     

反应性液晶修饰的光敏聚芳醚光取向稳定性研究

采用反应性液晶通过光聚合反应与聚芳醚光取向膜复合方法,制备了平面转换(In-plane switching,IPS)液晶显示器件,并在高温状态下对其光电显示和取向稳定性能进行了研究。结果显示,与单一聚芳醚光取向膜相比,利用复合光取向膜制备的IPS器件在高温状态下的光电显示和液晶取向稳定性能都得到了明显提高,在65℃明亮显示20h无液晶取向变化,在120℃维持2h无明显光量渗透。在线偏振紫外光下,光敏聚芳醚薄膜发生各向异性光交联反应,其交联程度最高可达67.4%。SEM分析结果发现,反应性液晶单体在UV光照射下,在聚芳醚光取向膜表面上发生了各向异性光聚合反应,沿先前光取向方向形成长度为0.4μm左右的棒状聚合物,有效限制了光取向膜中未交联的柔性基团的活动能力,进而有效增强了复合取向膜对液晶的取向稳定性。     

晶体与微声材料

0015959液晶物理[刊]/李伯符//液晶与显示.—2000,15(2).—131～153(B)0015960液晶材料电阻率测试方法研究[刊]/冯凯//液晶与显示.—2000,15(2).—120～124(B)介绍了用电流法测定液晶电阻率的方法。用该方法测得的电阻率数据比较稳定,基本上能够准确反映液晶材料的纯度及功耗。0015961各向异性 PDLC 散射膜的特性研究[刊]/王维强//液晶与显示.—2000,15(2).—101～107(B)采用摩擦表面取向层的方法制备了有光学各向异性结构的 PDLC 膜。研究了液晶盒的厚度、摩擦强度,以及在紫外光诱导相分离过程中的光照强度对 PDLC膜的光学各向异性程度和电光特性的影响。对 PDLC的光学各向异性进行了研究,并给出了要获得低阈值电压、高各向异性的聚合物分散液晶各向异性膜的盒     

用偏振器作基板的液晶显示板

本文研究了用偏振器作基板的液晶显示板(LCD),对使用双轴压延聚酯膜和单轴压延聚酯膜的TN LCD的光学特性进行了评价。结果,后者选作偏振器的支撑膜。因单轴压延聚酯膜和液晶分子呈光学各向异性,双折射会引起干涉色。又因聚酯膜是热各向异性,热处理后LCD板会起翘。文中就偏振器配置对LCD的热性能和光学性能的影响进行了讨论,确定了最合理的结构。所开发的塑料LCD的厚度为0.5mm,比普通使用玻璃基板的LCD有较好的光学性能。     

胶囊化胆甾液晶薄膜在不同基板下的光电性能

采用紫外光聚合诱导相分离法制备了胶囊化胆甾液晶薄膜,系统研究了玻璃和塑料基板对于驱动电压、反射率及对比度等显示性能的影响。研究表明:不论是玻璃或塑料基板,液晶胶囊化均有助于显示对比度的提升,同时相应的驱动电压也有所增加。相较于刚性的玻璃基板,在柔性基板下液晶胶囊化前后的驱动电压由70V增加到200V,显示对比度达到6.2∶1。总体而言,初步实现了胆甾液晶的柔性显示。     

等离子体处理过的基板上液晶平行取向的两种模式

我们提出了一种用于液晶盒的新取向工艺,可以得到0或非0的预倾角。这项工艺是用定向的等离子体流倾斜辐照基板。我们用一个阳极层发射器(anodelagerthruster)作为等离子体辐射源,以产生层状的等离子体流。它适合于处理大面积基板,可以处理有机(聚合物)和无机(玻璃,ITO)层。等离子体流辐照可以得到两种类型的液晶取向:(1)最可及(择优)取向轴位于离子束方向和基板法线组成的入射平面上;(2)最可及取向轴垂直于入射面。随着照射总剂量的增加,取向方向可以从类型(1)向类型(2)转变。在第一种取向模式中,可以通过改变工艺参数,如入射角、离子流密度和离子能等来改变预倾角。第二种取向模式的特征是预倾角为0。第一种模式的方位锚泊能系数相对较弱(W=10-3 Erg/cm2),而第二种类型锚泊能很强(W>10-1 Erg/cm2),与摩擦聚合物基板相当。两种模式的取向特征可以用来产生满足所需参数的取向,和构图(pattern)液晶盒基板。这种工艺方法可以克服传统摩擦工艺的某些缺点。     

一种新型液晶垂直取向膜

采用离子沉积法在玻璃基板表面制备了十四烷基磺酸盐自组装膜,用带有该自组装膜的基板制成的液晶器件呈现出垂直取向效果。通过自组装反应过程分析,认为自组装膜表面的纵向沟纹引起了液晶的垂直排列。实验发现,当自组装膜烷烃碳链长度大于11个C原子就可获得垂直取向。这种取向膜制作过程简单、热稳定性好,非常有望应用于多畴垂直取向模式的液晶显示器。     

液晶聚合物膜基板材料的应用

概述了液晶聚合物膜用作基板材料的优良性能以及制作PALAP基板的应用。     

磁场作用下液晶材料参数和锚定能的测试

介绍了在磁场作用下液晶材料的介电常数各向异性，磁化率各向异性，展曲弹性常数，扭曲弹性常数，弯曲弹性常数，以及在不同锚定强度下液晶分子与取向基板间的极化锚定能，方位锚定能的测试原理和测试技术。同时简单介绍了液晶材料的取向有序度，易取向轴和磁相干长度的磁场测试方法。     

IPS-LCD using a glass substrate and an anisotropic polymer film

A lightweight in-plane-switching liquid crystal display (IPS-LCD) using a single glass substrate and an anisotropic polymeric film is demonstrated. The liquid crystal molecules are aligned by the elongated polymer grain of the film. The alignment capability of the anisotropic film is comparable to a buffed polyimide layer. Compared to the LCD using two glass substrates, our new device exhibits a comparable contrast ratio (/spl sim/514:1), driving voltage, and response time because of good LC alignment. Such an anisotropic film can also function as a phase compensation film for widening the viewing angle. This technology is particularly attractive for making single-substrate displays and also has potential for a double-layered guest-host display and a flexible display using IPS LCDs.     

整合型液晶邦定机

用于液晶显示屏制作过程中的邦定技术目的是使TCP或FPC(柔性电路板)与ITO玻璃之间建立稳定连接的生产工艺,是液晶显示屏制作过程中的主要设备之一.介绍了针对液晶显示器制作工艺开发出的整合型邦定机,整合了各向异性导电膜(ACF)机构、预压对位机构、主压邦定机构.重点介绍了该设备的工作原理、系统控制设计、软件控制并指出了...     

An optically controlled liquid crystal device using azopolymerfilms

We have developed a liquid crystal (LC) device that is totally controlled using light. The initial alignment is made by optically buffing the azopolymer film with two coherent argon laser beams. Surface relief gratings have been optically induced on an assembled cell filled with LC. A single linearly polarized argon laser beam is then employed to irradiate the sample and photoinduce a twisted alignment structure. This can then be erased by a circularly polarized beam. The alignment information can also be erased by heating to the glass transition temperature of the azopolymer film     

Strong Vertical Alignment of Liquid Crystal on Porous Anodic Aluminum Oxide Film

Properties of anodic aluminum oxide (AAO) film as a liquid crystal (LC) alignment material is studied. We deposit the transparent porous AAO film on glass with the diameter of the pores controlled between 17–65 nm. The liquid crystal can be aligned vertically against the substrate with the AAO film. The measured polar anchoring strength is about 1.5 $,times 10 ^{-5} {rm J/m} ^{2}$, which is comparable to that of N,N-dimethyl-N-octadecyl-3-aminopropyl -trimethoxysilyl chloride (DMOAP) layer. AAO films with smaller pore diameters exhibit higher anchoring strengths. On the other hand, the uniformity of the pore array in the AAO films does not affect the alignment quality significantly.      

侧链密度对聚酰亚胺取向膜性能的影响

成功地合成了二胺单体十二烷氧基苯-4′,4″-二氨基三苯胺(DPDTA),并用此单体与3,3′-二甲基-4,4′-二氨基二苯甲烷(DMMDA)和二苯醚四羧酸二酐(ODPA)共缩聚,采用低温缩聚-热酰亚胺化、通过调节共聚物组成制备了2种聚酰亚胺(PI)。利用FT-IR、NMR、UV-Vis与DSC等手段对合成二胺单体及PI进行了结构表征和性能测试。研究了其取向性能、透光性能和耐热性能。结果表明,在摩擦前,含10%DPDTA的PI不能诱导液晶分子取向,含25%DPDTA的PI能诱导液晶分子垂直取向,预倾角可达89.6°。而摩擦后,两种PI都能使液晶分子平行取向,预倾角分别为1.8°和2.4°。两种PI膜在500～800nm区域透光率都在80%以上,玻璃化温度都在230℃以上。     

Anisotropic Change of Liquid‐Crystal Domains by Polarized Infrared Pulse Laser Irradiation for a Columnar Mesophase

The infrared photoinduced alignment change of liquid‐crystal domains was investigated for a hexagonal columnar mesophase of a liquid‐crystalline triphenylene derivative. A uniform and anisotropic alignment change of domains was observed when a polarized infrared (IR) light corresponding to the wavelength of the aromatic C–C stretching absorption band of the triphenylene core was used to irradiate the sample. The relationship between the aligned azimuthal angle of the columnar axis and the polarization of the IR incident irradiation was investigated. IR absorption dichroism is induced as a result of the reorientation of triphenylene core. Texture observation and polarizing microscope FTIR spectra show that a change of the molecular alignment occurred and that the direction of columns depends on the polarization angle of the IR light used for irradiation. The mechanism of the alignment change in a columnar liquid crystal film by IR irradiation is also discussed. The technique could provide a novel technology to control the columnar alignment of highly viscous liquid crystals.     

一种采用内部线栅偏振片的半透半反射式液晶显示器

为了同时获得具有高透射率和反射率的液晶显示器,提出了一种采用内部线栅式偏振片(wiregridpolarizer,WGP)的单倍盒间距的半透半反式液晶显示器方法。在反射模式中,液晶盒内嵌的WGP作为依赖于偏振的外界光的反射器;在透射模式中,不需要消色差的四分之一波片。基于液晶盒的初始取向,该器件可用于正常显黑模式(垂直取向)和正常显白模式(扭曲向列相取向)。本文研究了这两种器件结构详细的电光特性,如电压依赖光效率特性和视角特性。     

Wide-View MVA-LCDs With an Achromatic Dark State

A multi-domain vertical alignment liquid crystal display (MVA LCD) using a negative C-plate and a biaxial film is proposed to obtain an achromatic dark state. In comparison to conventional approach which uses a negative C-plate and a positive A-plate, the maximum light leakage over entire viewing cone is reduced by ~ 6X at lambda = 450 nm and ~ 4X at lambda = 650 nm. The achromatic dark state is essential for improving the contrast ratio, viewing angle and color saturation of MVA LCDs.     

A transflective liquid crystal display using an internal wire grid polarizer

To obtain high transmittance and reflectance simultaneously, a single cell gap transflective liquid crystal (LC) display using internal wire grid polarizer (WGP) is proposed. For the reflective mode, the imbedded WGP serves as a polarization-dependent reflector for the ambient light. For the transmissive mode, no achromatic quarter-wave film is needed. This device can be used as a normally black mode (using vertical alignment) and a normally white mode (using twist-nematic alignment), based on the initial LC cell alignment. Detailed electro-optic performance, such as voltage-dependent light efficiency and viewing angle of these two device configurations, is investigated.