向列液晶在聚酰亚胺LB膜上的表面取向(英文)

本文研究了液晶和聚酰亚胺分子在聚酰亚胺LB膜上的取向效果。聚酰亚胺链在LB膜中的取向程度低于强摩擦膜表面聚酰亚胺链的取向,这可能由于聚酰亚胺分子的结构线性不好所致。9或11层LB膜可以很好地排列液晶分子,但液晶在聚酰亚胺LB膜上的取向效果劣于强摩擦膜表面的情形。     

聚酰亚胺液晶垂直取向膜的表面取向分析

采用均苯四甲酸二酐(PMDA)、4,4′-二胺基二苯甲烷(MDA)以及侧基含联苯和己基的二胺(TBCA)三元共聚制备了聚酰亚胺垂直取向剂,摩擦前后得到相同的垂直取向效果,探讨了侧链二胺TBCA的含量对聚酰亚胺取向膜垂直取向性能的影响,采用衰减全反射红外光谱(ATR-FTIR)对摩擦前后聚酰亚胺膜表面侧链的相对含量进行了对比,并运用原子力显微镜(AFM)考察了表面细微沟纹对液晶分子取向的影响。结果表明,在取向膜未经摩擦没有产生表面沟纹的情况下液晶分子也能取向,并且这类取向膜表面侧链的含量与摩擦后的含量相当。     

微纳米尺度下聚酰亚胺薄膜表面电荷生成规律研究

为进一步研究工业中对聚酰亚胺取向膜基板进行摩擦取向处理时,在取向膜上产生静电残留,影响液晶分子取向的均匀性的问题,文章利用Dimension3100型扫描探针显微镜(SPM)在聚酰亚胺表面摩擦产生了微纳米尺度的电荷,并对表面电荷的生成规律进行了研究。当SPM的导电探针在聚酰亚胺表面进行加工或摩擦操作时,会在探针与薄膜接触区域产生电荷,生成的电荷可以用静电力显微镜(EFM)进行观察。讨论了生成电荷的极性、数量、区域大小与摩擦过程中探针加工速度,所加电压大小、正负之间的关系,为在微观尺度探索聚酰亚胺表面电荷生成规律及生成机理提供了一种新的途径。     

聚酰亚胺的侧链结构对液晶取向性能的影响

聚酰亚胺取向膜是液晶显示器的重要组成部分,对显示器件性能具有重要影响。通过实验室自行合成的两种不同侧链的二胺单体,与4,4'-二胺基二苯甲烷和均苯四羧酸二酐聚合得到含有酯键型侧链和含有醚键型侧链结构的两种聚酰亚胺。通过偏光显微镜观察,液晶分子在两种聚酰亚胺取向膜上都获得了均匀取向。测试了不同侧链结构的聚酰亚胺取向膜产生的预倾角,发现含有酯键型侧链结构的聚酰亚胺比含有醚键型侧链结构的聚酰亚胺产生的预倾角略大,且取向稳定性更好。     

聚酰亚胺液晶垂直取向膜的制备与性质

虽然传统的平行取向技术已广泛应用于液晶显示器的生产,但其存在窄视角、低对比度和慢响应时间等问题,因此液晶分子的垂直取向技术在国外已经被广泛研究。在实验中,一种含有液晶结构侧链的聚酰亚胺通过均苯四羧酸二酐(PMDA),4,4′-二胺基二苯甲烷(MDA)和4-己氧基联苯酚-3′,5′-二胺基苯甲酸酯(C6BBDA,实验室自制)共聚被制备,并且被用作液晶取向膜,研究其取向性能。试验发现,该种聚酰亚胺作为取向膜可以诱导液晶分子垂直取向,即使在摩擦之后依然可以获得大于89°的预倾角;使用正交偏光显微镜观察所制得液晶盒中的液晶取向效果,发现垂直取向均匀良好;为了测试该垂直取向的热稳定性,将制备的液晶盒在120℃下烘烤12h后,偏光显微镜下观察发现垂直取向仍然良好均匀,表明该取向膜具有良好的热稳定性。     

新型相邻长支链取代的聚酰亚胺液晶垂直取向剂的合成及其用于液晶显示元件的性能表现

报道了一类新型相邻柔性长支链聚酰亚胺液晶垂直取向剂的合成,并考察其用于液晶显示元件的性能表现。首先,以2,3,4-三氟硝基苯、4-(4-庚基环己基)-苯酚、邻苯二甲酰亚胺钾盐等原料合成了含有相邻柔性长支链结构的新型功能性对苯二胺(L-14),通过核磁共振波谱(NMR)和高压液相色质联用(HPLC-MS)对目标产物进行结构表征。用1,2,3,4-环丁烷四甲酸二酐(CBDA)、对苯二胺(PDA)和L-14制备了一类PDA与L-14不同比例的聚酰亚胺液晶垂直取向剂,并对以该聚酰亚胺膜作为液晶取向层制得的液晶显示元件开展了预倾角、液晶定向时间、陡度、对比度等性能测试。结果表明,基于该新型聚酰亚胺液晶垂直取向膜的液晶显示元件耐磨性能强、液晶定向时间短、取向性能优良、显示画面清晰。     

单玻璃基板与各向异性聚合物膜的IPS-LCD的应用

介绍了一种使用单片玻璃基板和各向异性聚合物膜的轻型、共面转换液晶显示(IPS-LCD)技术。液晶分子由伸长的聚合物膜内的颗粒排列。各向异性聚合物膜的取向性能与聚酰亚胺(PI)摩擦层相当。良好的液晶取向性能使新器件的对比度(514:1)、驱动电压和响应时间都能够与双玻璃基板LCD相比拟。这种各向异性膜也能作为拓宽视角的相位补偿膜来使用。该技术特别引人注目之处在于制作单基板显示器,同时它也具有实现双层宾主显示和IPS-LCD柔性显示的潜在应用。     

聚酰亚胺在液晶显示器件中的应用

文章介绍了聚酰亚胺具有的优异性能,以及聚酰亚胺薄膜在液晶显示器中的应用情况.重点论述了聚酰亚胺薄膜在液晶显示器取向膜、液晶面板与驱动电路的柔性连接、驱动芯片封装、液晶面板彩色滤光片中的应用.在不同方面的应用中,对聚酰亚胺薄膜结构、性能和工艺过程的要求有较大区别,文中进行了详细的分析论述.     

向列液晶-聚酰亚胺LB膜的方位表面锚定能的研究(英文)

利用我们研究组提出的力矩平衡的方法,测定了向列液晶在聚酰亚胺LB膜上的方位表面锚定能。向列液晶在聚酰亚胺LB膜上的方位表面锚定能低于强摩擦聚酰亚胺膜的情形。液晶和聚合物分子间的相互相用对于聚合物表而的液晶排列是非常重要的。     

聚酰亚胺添加剂对液晶预倾角的影响

液晶取向剂是制造液晶显示器的关键材料之一.目前对聚酰亚胺结构对液晶预倾角的影响研究较多,而添加剂对预倾角影响的研究还较少.文章用均苯四甲酸二酐(PMDA),4[(4-氨基苯基)-二(4-甲氧基苯基)甲基]苯胺,1,2,3,4-环丁烷四羧酸二酐(CBDA),4-己烷氧基联苯酚-3′,5′-二胺基苯甲酸酯和不同含量的添加剂制备了聚酰亚胺液晶取向剂.通过偏光显微镜观察,液晶分子在4种PI膜上都获得了均匀取向.研究发现,含添加剂的PI膜具有良好的耐溶剂性能,液晶分子的预倾角随添加剂含量的增加先增大后减小.     

Super‐Fast Switching of Twisted Nematic Liquid Crystals on 2D Single Wall Carbon Nanotube Networks

We have developed a high performance liquid crystal (LC) alignment layer of ultra‐thin single wall carbon nanotubes (SWNTs) and a conjugated block copolymer nanocomposite that is solution‐processible for conventional twisted nematic (TN) LC cells. The alignment layer is based on the non‐destructive solution dispersion of nanotubes with a poly(styrene‐b‐ paraphenylene) (PS‐b‐PPP) copolymer and subsequent spin coating, followed by conventional rubbing without a post‐annealing process. Topographically grooved nanocomposite films with two dimensionally (2D) networked SWNTs embedded in a block copolymer matrix were created using a rubbing process in which bundles of SWNTs on the composite surface were effectively removed. The LCs were well aligned with a stable pre‐tilt angle of approximately 2° on our extremely transparent nanocomposite, which gave rise to superfast switching of the TN LC molecules that was approximately 3.8 ms, or four times faster than that on a commercial polyimide layer. Furthermore, the TN LCD cells containing our SWNT nanocomposite alignment layers exhibited low power operation at an effective switching voltage amplitude of approximately 1.3 V without capacitance hysteresis.     

液晶显示器摩擦取向技术的新发展

摩擦取向技术一直是液晶显示器领域使用最广泛的取向技术和研究热点。介绍了液晶显示器摩擦取向技术在取向工艺、取向理论、取向材料、检测方法等方面的新进展和局限性。     

Liquid Crystal Alignment Layer With Controllable Anchoring Energies

We demonstrate a liquid crystal alignment layer with controllable polar and azimuthal anchoring energies. This alignment layer is based on a nanostructured surface formed by mixing a conventional polyimide and a nonaligning polymer. By using this variable anchoring alignment layer, large cell gap bistable twisted nematic LCD requiring asymmetric anchoring can be fabricated.     

表面摩擦对反射式胆甾相液晶显示器件对比度的影响

主要通过p态和fc态的反射特征曲线来研究取向层的摩擦强度对胆甾相液晶显示器件对比度的影响。随着摩擦强度的增大,器件的对比度先增大后减小,在摩擦强度为25.26mm时,器件的对比度达最大,约为5.66。结果表明,对取向层进行适当的摩擦处理,可以得到对比度较高的显示器件。     

STN-LCD制造摩擦工艺及静电消除工艺探讨

定向层（PI层）是STN－LCD合铁一个重要组成部分。因为简单地把液晶夹在两片玻璃基板之间，很难获得均匀的液晶分子排列，只有在基板作上定向层并作摩擦处理后，液晶的物性常数因分子排列状态才会发生变化，液晶分子对于电场等外力的响应也会变得有序。所以，研究液晶分子的排列定向技术，在液晶显示元件构成技术上具有重要意义。     

How far has the molecular alignment of liquid crystals been elucidated?

Liquid crystal displays (LCDs) - born in late 1960s - have become a 45 billion-dollar industry in 2004. Today's LCD panels cover a wide range of sizes from 0.2 to 82 in diagonal. The electro-optical characteristics of any field effect LCD are determined by the orientation of its liquid crystal (LC) molecules at the display boundaries. Until recently most LCD alignment processes were based on rubbing polymer coated LCD substrates with a cloth. Despite its key importance, the complex mechanism governing the alignment of LC molecules on display substrates is still not well understood. Do the microgrooves generated by rubbing induce LC-alignment or does the stretching of polymer chains as a result of brushing cause it? To overcome the drawbacks of conventional aligning techniques, new alignment processes have recently been proposed and developed. Examples are micro embossing, ion bombardment, fringe field effects and photo-alignment. In this paper, some mechanisms of LC alignment are discussed and various alignment techniques and methods to investigate the interaction of LC molecules with substrates are reviewed.     

LPP聚酰亚胺取向膜的制备及其取向研究

合成具有光敏性的聚酰亚胺OPDA－BAPAF－Cin－CN,对其化学性质进行研究。用这种聚酰亚胺作为光致取向剂,能对液晶MLC－LC2000有良好的取向效果。研究了这种取向剂对液晶MLC－LC2000的取向方向及提高预倾角的作用,发现该取向剂有良好的热稳定性。     

光配向制程参数对预倾角及其光电性能的影响

为了满足市场对LCD面板高对比度、高画质的需求,光配向作为一种非接触式的新型配向方法正被广泛研究。本文采用光裂解型聚酰亚胺取向材料制备得到IPS型测试液晶盒,并针对光配向成膜条件与其所形成的光电效应进行研究。通过FT-IR、AFM、偏光板角度测试机等仪器对不同pre-bake和post-bake温度和时间下的测试盒的预倾角及光电特性进行了表征。结果显示,pre-bake、post-bake的温度和时间与预倾角、穿透率、对比度和电压保持率均存在一定的相关性。本文的研究可以为后人对光配向制程相关参数的优化提供借鉴。     

IPS液晶取向膜表面光学各向异性DΔ的研究

针对共面转换IPS(In-Plane-Switching)液晶显示模式取向膜,利用反射椭偏消光法测量了取向膜表面的光学各向异性DΔ值。研究了在不同摩擦条件和亚胺化温度条件下,取向膜表面光学各向异性值DΔ值的变化。研究结果表明,随着亚胺化温度升高,DΔ值呈现下降趋势。在摩擦强度各因子中,压入量和转速对于DΔ值影响较大。DΔ值可作为一种定量化评价取向膜取向状态的方法,并可作为生产过程中对于液晶稳定性取向的管控方法使用。     

Assembly of Photopolymerizable Discotic Molecules on an Aligned Polyimide Layer Surface to Form a Negative Retardation Film with an Oblique Optical Axis

Ultraviolet (UV) polymerizable discotic liquid‐crystalline (DLC) molecules (2,3,6,7,10,11‐hexakis(4′‐acryloy‐m‐alkyloxybenzoyoxy)triphenylene [HAHBT‐m, where m was the number of methylene units, and here m = 6 (HAHBT‐6)]) were assembled to form a negative retardation film with an oblique optical axis on a specifically designed rubbing‐aligned polyimide layer surface [6FDA‐11CBBP (where 11 is the number of methylene units in the side chains)]. The side chains of this polyimide were terminated by cyanobiphenyl groups. Surface‐enhanced Raman scattering (SERS) and optical second harmonic generation results showed that rubbing caused a surface structural re‐arrangement in the alignment layer resulting in a negative pre‐tilt angle (θ_s) of –8.5° (which was in the direction opposite to the rubbing direction). The molecular topology at the rubbed surface was governed by a stable fold‐like bent structure of the cyanobiphenyl side chains, in which the CN groups preferentially pointed down towards the surface. When the DLC molecules were deposited onto the alignment surface and polymerized via UV irradiation to generate a new optical film, an oblique optical axis with an average tilt angle of –18.6° with respect to the film normal was detected using ellipsometric measurements. This tilted optical axis was developed by the DLC molecules being wedged on top of the cyanobiphenyl groups when in the bent conformation. Furthermore, the tilt angle difference between the θ_s at the alignment surface and at the air interface of the DLC molecules was attributed to a splay deformation of the DLC molecules along the film surface normal. Optical modeling has also confirmed our experimental observations.