共查询到20条相似文献,搜索用时 31 毫秒
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开发了一种新的双向取向表面。所述取向表面可以用于控制液晶引流(backflow)方向。基于所述新型取向层,成功制造了一种双稳态扭曲向列相LCD,该LCD在U和T态之间转换,不伴随表面锚泊能的破坏(surface anchoring energy breaking)。 相似文献
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《Display Technology, Journal of》2009,5(9):350-354
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在受等离子辐照过的一些有机和无机的基板上,获得了高质量的液晶共面取向。与已知的用来改善顶部锚定及预倾角各向同性的等离子处理方法不同,新方法是将等离子束调整到倾斜射向待取向的基板。在所用的辐射参数范围内,所有基板上的LC取向的易取向轴(easy axis)都平行于等离子体传播方向。研究了LC的预倾角和锚定能与等离子束的入射角、辐照时间、能量以及辐照电流密度等的依赖关系。经等离子处理过的基板上,方位角、锚定能与用光取向方法得到的相近,而预倾角与摩擦产生的类似。透过率-电压曲线与等离子处理的和摩擦工艺处理的非常接近。与摩擦取向相同,等离子诱导的取向具有很高的温度和光照的稳定性。也考虑了采用等离子/偏振紫外光和等离子/摩擦处理等组合方法来制作LC图形。 相似文献
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Oleg Yaroshchuk Ruslan Kravchuk Andriy Dobrovolskyy Liou Qiu Oleg D.Lavrentovich 谢萍 《现代显示》2003,(6):26-30
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。 相似文献
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Min Ju Park 《Microelectronic Engineering》2008,85(11):2261-2265
In this study, we have fabricated polyacrylate substrates having a nano-patterned surface topography using a soft-imprint technique. The planar alignment of liquid crystals (LCs) along the direction of nanogrooves has been generated. Twisting behavior of nematic LCs has been also observed with a perpendicularly assembled LC cell and the cell parameters can be estimated by using the Soutar and Lu method. By comparing the anchoring energies obtained, accordingly, it has been demonstrated that the polymer nanogroove pattern has a comparable influence on LC alignment to the conventional rubbing process. It has been also shown that the artificial topography of the line grooves on the conventionally rubbed surface has a significant influence on the anchoring stability of the LC molecules. 相似文献
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弱锚定条件下平行排列向列液晶盒的一级转变 总被引:1,自引:1,他引:0
在液晶总自由能中界面锚定能采用修正后的Rapini-Papoular(RP)公式,用严格的数学推导和计算,详细研究了弱锚定条件下平行排列的向列液晶盒在阈值点的弗雷彼里克兹(Freedericksz)转变问题。结果表明,对所研究的液晶盒在一定条件下阈值点的转变可以是一级转变。同时给出了一级转变条件,它与液晶表面参量有关。 相似文献
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本文研究径向电场作用下同心柱筒中混合排列向列相液晶的指向矢分布,重点研究挠曲电效应对指向矢分布的影响。向列相液晶处于同心圆柱构成的薄层间,内表面径向锚定、外表面轴向锚定以及内表面轴向锚定、外表面径向锚定构成两种同心柱筒混合排列模型。基于向列相液晶Frank弹性理论,通过差分迭代方法,分别在强锚定及弱锚定边界条件下,研究了两种模型中挠曲电效应对指向矢分布的影响。研究结果表明:挠曲电效应在薄层内边界、外边界以及薄层内部对指向矢分布有着不同的影响;同心柱筒中指向矢分布由柱对称性、边界锚定作用、介电耦合作用、挠曲电效应的综合作用所决定。 相似文献
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Three new photoreactive brush polyimides (PSPIs), each bearing a different type of chromophore (cinnamoyl (CA), 3‐(2‐furyl)acryloyl (FA), and methacryloyl (MA)) in their bristles (i.e., side groups), are successfully synthesized, and are found to produce good‐quality films with smooth surfaces through conventional spin‐casting and drying processes. These PSPI polymers are thermally stable up to 320 °C. This is the first quantitative investigation of the photoaligning and rubbing‐aligning processabilities of PSPI polymer films, and of the abilities of the resultant films to control the orientation and anchoring of liquid‐crystal (LC) molecules. The chromophores of both poly(1‐cinnamoyloxy‐2,4‐phenylene hexafluoroisopropylidenediphthalimide) (6F‐DAP‐CA) and poly(1‐3‐(2‐furyl)acryloyloxy‐2,4‐phenylene hexafluoroisopropylidenediphthalimide) (6F‐DAP‐FA) PSPIs are found to undergo photodimerization in thin films and, to a lesser extent, photoisomerization, resulting in insoluble, crosslinked films. The MA chromophores of 6F‐DAP‐MA PSPI are found to undergo photopolymerization in thin films, which might include photodimerization to a lesser extent, resulting in insoluble, crosslinked films. Thin films of the PSPI polymer chains are found to have excellent unidirectional orientation ability as a result of either photoexposure with linearly polarized UV light (LPUVL) or rubbing. Both the photoaligned and the rubbing‐aligned polymer chains in the PSPI films are demonstrated to effectively induce the alignment of nematic LCs along their orientation directors by anisotropic interactions between the preferentially oriented polymer chain segments and the LCs. The contribution to LC alignment of the microgrooves developed in the rubbed films is found to be very low. The anchoring energies of the LCs on the photoaligned film surfaces are comparable to those on the rubbing‐aligned film surfaces; the anchoring energies are found to be in the range 0.45–2.25 × 10–5 J m–2, and to depend on which film treatment process is used and which chromophore bristle is present. In summary, the new PSPIs reported in this paper are promising LC alignment‐layer candidates with rubbing‐free processing for the production of advanced LC‐display (LCD) devices, including LCD televisions with large display areas. 相似文献
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D. Sainova A. Zen H.‐G. Nothofer U. Asawapirom U. Scherf R. Hagen T. Bieringer S. Kostromine D. Neher 《Advanced functional materials》2002,12(1):49-57
Liquid‐crystalline (LC) polyfluorenes have been successfully aligned on photoaddressable polymers (PAPs). This is the first example of the alignment of a LC main chain polymer on a photoaligned layer. The degree of molecular alignment in the fluorescent polyfluorene layer on top of an ultra‐thin PAP layer is shown to depend strongly on the chemical nature of the PAP. Good alignment with dichroic ratios of more than 10 was only achieved with PAPs containing liquid‐crystalline side chains. Patterning with laterally structured alignment was realized in several ways, utilizing reorientation with orthogonally polarized light. Thin PAP layers have further been utilized as hole‐conducting alignment layers in polymer light‐emitting diodes (LEDs) with polarized emission. In order to facilitate hole transport through the alignment layer, different concentrations of a hole‐transporting molecule (HTM) have been mixed into the PAP layer. These hole‐conducting alignment layers retained their aligning abilities even at HTM concentrations of 20 wt.‐%. LEDs with photometric polarization ratios in emission of up to 14 at a brightness of up to 200 cd/m2 and an efficiency of 0.3 cd/A could be realized. 相似文献
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在具有高驱动电压的液晶显示器中,为了对液晶器件起到保护作用,以采用增加取向层厚度的方法来解决某些显示器件由于驱动电压过高导致的问题。当取向层厚度不可忽略时,随着取向层厚度增加会导致器件驱动电压升高。本文利用扭曲向列相液晶显示器结构,通过模拟和实验分析了取向层厚度对LCD的影响以及不同介电常数的取向层对LCD的影响。结果表明:当取向层的介电常数大于20时,能够有效降低TN-LCD驱动电压。当其介电常数大于500时,其厚度变化对驱动电压的影响变得很小。本文结果对降低高驱动电压液晶器件的驱动电压有重要的指导性意义。 相似文献
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有限元法求解液晶层中的指向矢分布 总被引:8,自引:5,他引:3
建立了基于有限元法的液晶层中指向矢分布的计算方法,可以方便地考虑非对称取向和表面锚定能及其形式对指向矢分布的影响,作为应用实例,给出了非对称弱锚定情形下的液晶层下指向矢分布的计算结果。 相似文献
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利用向列相液晶弹性理论,研究了混合排列柱状薄层中的向列相液晶指向矢的分布。向列相液晶被限定在两个同心圆柱构成的薄层中,在内外表面施加强锚定及弱锚定边界条件,锚定易取向方向取径向和轴向(垂直柱轴及平行柱轴)的边界条件,得到了四种混合排列柱状薄层模型RsZw、ZwRs、RwZs、ZsRw。基于Frank弹性自由能和Rapini-Papoular近似的表面能,研究了不同锚定强度、不同内半径及不同弹性常数值的指向矢分布,计算机模拟得出指向矢取向的曲线图。由于柱对称性、锚定强度、薄层厚度以及弹性各向异性共同竞争的影响,这四种模型的指向矢分布有着很大的不同。 相似文献
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Liquid crystal (LC) photo-alignment using azo-dyes is reviewed. This alignment method is very different from previously reported ones, which are due to mechanisms such as photo-crosslinking, photo degradation, and photo-isomerization. We present the basic physical mechanisms of the photo-induced orientational order in various photo-aligning materials and in azo-dye layers in particular. This method is based on rotational diffusion in a potential created by the light field as well as intermolecular forces. It will be shown that this photo-aligning method can provide a controllable pretilt angle and strong anchoring energy of the LC cell, as well as having high thermal and ultraviolet (UV) stability. The application of this method to the alignment and fabrication of various types of LC displays is also discussed. 相似文献