电控双折射盒中指向矢分布的计算

在液晶弹性理论的基础上计算了电控双折射盒中的指向矢分布和延迟量。讨论了弱锚定边界条件对指向矢分布和延迟量的影响。本文结果对电控双折射盒的设计有一定的参考价值。     

利用微锥膜改善反射式液晶显示器件的视角

提出了一种可以改善反射式彩色液晶显示视角的微锥结构膜。模拟计算结果表明,当光从微锥的底部人射时,该膜起到准直作用,当光从微锥的顶部入射时,该膜起到散射作用。利用微锥膜可显著改善反射式干涉滤光膜的视角依赖性。由于微锥膜的作用不依赖了液晶盒结构,所以,可对多种结构的反射式彩色液晶显示有效。     

Suppression of the viewing angle dependence by introduction of nanoporous diffuser film on blue OLEDs with strong microcavity effect

A nanoporous polymer film composed of cellulose acetate butyrate was prepared, which showed an optical haze property of approximately 40%. This film was applied as a diffuser film to improve the viewing angle dependence of microcavity structured organic light emitting diodes (OLEDs). We prepared this film by simply using a spin-coating process with a continuous supply of water mist from a humidifier. Air voids or pores with diameters ranging from 300 nm to 500 nm were found inside the polymer film, to produce three-dimensional (3D) nanoporous polymer films with random distribution. We applied this film to a blue fluorescent OLED device with strong microcavity effect. The film did not affect the total external quantum efficiency (EQE) observed using an integrating sphere. However, the current efficiency collected from the normal direction was reduced by 25%, which means that the film spread out or scattered the light emitted from the OLED device. As a result, we obtained blue microcavity OLEDs with efficiently reduced viewing angle dependency.     

Improvement of viewing angle dependence of the white organic light emitting diodes with tandem structure by introduction of nanoporous polymer films

We fabricated nanoporous polymer films (NPFs) with different pore size distribution [e.g., P1 (3000–5000 nm), P2 (1000–1200 nm), and P3 (300–500 nm)] by using simple spin coating process and utilized those NPFs as a viewing angle compensation layer for white organic light emitting diodes (WOLEDs) with tandem structure. In this research, all NPFs could alleviate serious peak wavelength shift according to the variation of viewing angle (e.g., up to angles of 60°). Especially, NPF with 300–500 nm air voids (P3) showed the best optical characteristic among three types of NPFs when we utilized them for WOLEDs with tandem structure. Indeed, P3 could efficiently reduce the color shift [Δ (u′, v′) of 0.0264] compared to that of WOLED without NPFs [Δ (u′, v′) of 0.0558] in Commision Internationale de l’Éclairage 1976 standards (CIE 1976), which implies such NPFs have great potential as a viewing angle compensation layer for the future.     

用胆甾液晶制备的新型宽视角透过式彩色滤光片

作出了一种胆甾液晶(cholesteric liquide-crysml，简称CLC)彩色滤光片的新设计。由于这个滤光体系不吸收光线，因此背光源的利用效率非常高。这类胆甾液晶膜系(CLCs)具有扩展的选择反射(selective renection)频带，和窄发光峰(频带)的RGB光源，如发光二极管(LEDs)配合就能减少色移(波长变化)与观察角度的关系，更有效地提高光源利用率。     

基于FFS架构实现宽窄视角切换

基于公共场合隐私保护的需求,宽窄视角可切换的液晶显示技术有着迫切的市场需求。现有宽窄视角切换技术不但增加了显示装置的厚度与成本,而且降低了原本宽视角模式下的显示效果。本文研究了一种基于负性液晶FFS模式的宽窄视角切换技术,它通过在彩色滤光片一侧形成高预倾角配向(40°～60°),在同侧第三电极施加弱电场时,液晶分子离轴方向具有较大相位延迟,形成大视角观看时的暗态漏光与对比度下降,实现窄视角显示模式。而同侧第三电极施加强垂直电场时,大的预倾角液晶分子因负介电各项异性使得倾角降低,可减少暗态漏光和提升对比度,实现宽视角显示模式。验证结果表明:宽视角模式时,其上下左右视角均可达到85°以上;而窄视角模式时,左右视角仅为40°,且具有较好的对称性。本技术结构简单,驱动灵活,在防窥显示领域具有很好的应用前景。     

反射型硅基液晶显示模式

文章列举了适用于反射型硅基液晶显示（LCOS）的关态常白和常黑反射型显示模式,模拟出电光曲线,着重关注液晶显示的驱动电压,RGB三基色色散,未放置补偿片,通过偏振分光棱镜（PBS）产生偏振光,改变扭曲角度,光学延迟量以及入射偏振光方向与临近液晶层取向夹角达到改变模式的目的。针对LCOS的不同要求,在显示模式之间进行了对比,为实际的模式设计提供了理论依据。     

一种宽视角和快速响应的连续视角可控液晶显示

在垂面排列液晶显示模式中,液晶分子垂直取向,具有暗态良好、高对比度的特点,但是其视角特性不佳。采用MVA和PVA技术等多畴结构可以使VA模式的视角情况得到改善,但MVA模式中凸起结构引起的液晶分子初始预倾状态会导致暗态漏光,从而降低显示的对比度。而PVA模式中的狭缝结构虽然不会影响对比度,但其响应速度比较慢。文中提出一种新型垂面排列液晶显示器结构,其像素电极四周刻蚀有弧形狭缝,公共电极中心刻蚀有孔洞。施加电压时液晶分子向中心倾倒,形成中心对称的多畴结构,实现了对比度均匀的宽视角,且这一结构在保证高透过率的同时还可以实现快速响应。另外,通过在公共电极上施加偏置电压,该结构还可实现视角的连续可控。     

基于频谱分析的运动模糊图像参数检测

为了提高运动模糊图像的运动方向和运动像素的检测精确度,本文提出了基于频谱分析的运动模糊图像参数识别的改进算法,从频谱分析的角度出发推导了暗条纹宽度、图像大小、条纹倾斜角度与运动尺度、运动像素之间的关系;采用二次傅里叶变换的方法细化亮条纹,分析并简化了条纹倾斜角与运动方向角之间的关系;分析了频谱中十字亮线产生的原因及位置,提出了去除十字亮线的新方法;然后,对处理后的频谱进行Radon变换,根据变换结果得出模糊图像的运动方向和运动像素。实验证明,该算法能够检测出不同大小模糊图像的运动方向和运动像素,检测误差控制在0.5°、2个像素的范围之内。     

新型多畴扭曲向列相液晶显示器

提出在像素电极下方放置凸起物,获得具有宽视角特性的多畴扭曲向列相液晶显示器。该模式比传统的多畴TN模式摩擦过程少,工艺过程简单。在这种液晶显示器中,初始状态(未加电)时,分子排列结构和普通单畴TN模式相同,在加电压状态时,由于凸起物的存在,液晶分子沿着4个不同的方向排列形成多畴区域。文中运用专业液晶模拟软件模拟,对该液晶显示器的电光特性进行研究,结果表明,该液晶显示器具有宽视角、色散小及色彩还原性较好的特性。     

Highly efficient white transparent organic light emitting diodes with nano-structured substrate

Enhancing outcoupling efficiency and stabilizing emission spectra are of high technical importance in realizing high quality white transparent organic light emitting diodes (TOLEDs). In this work, we demonstrate a random nano-scattering layer (RSL) as a structure which can effectively address those tasks. The RSL contributes to bottom and top emissions by scattering and reflection, respectively. With the use of RSL, we achieved remarkable total efficiency enhancement of 101%. Also, a viewing angle independent stable white spectrum with a color rendering index of 79 was achieved. With its straight forward processing, our RSL can be readily applied to deal with various photonic applications to enhance both efficiency and emission spectra.     

AFFS技术在大尺寸LCD-TV的进展（英文）

最近我们发展了AFFS技术,做出了32″LED背光源的LCD-TV,色域达到了105%,对比度1200：1,在140°所有视角的对比度达到了100以上,我们采用双轴补偿膜大大提高了颜色漂移的特性。这些光学特性结果的取得是与工艺制作、光学材料的优化、新AFFS像素的设计分不开的。     

PDLC膜黑白显示原理及其光电性能研究

文章阐述了基于正交偏正片实现PDLC膜的黑白显示机理,并基于正交偏振片研究了PDLC膜的电光特性,实现PDLC膜黑白显示。研究发现,PDLC膜的阈值电压Vth和对比度CR(0°)随膜厚、单体含量增加呈减小的趋势,与无正交偏振片下的PDLC膜相关特性相反;而饱和驱动电压Vdr随膜厚、单体含量增加而增大,且可视视角宽度随膜厚增加而减小,与无正交偏振片下PDLC膜相关特性变化趋势基本一致;透射光强与视角之间存在M型特性。     

Top-emitting organic light-emitting diodes integrated with thermally evaporated scattering film for reducing angular dependence of emission spectra

A scattering film is obtained by thermally evaporating tetraphenylethene (TPE) onto the substrate. The TPE molecules self-crystallize themselves as microsheet on reaching the substrate. The resultant TPE films exhibit strong light scattering effect because of the random distribution of the crystallized sheets. The scattering films, being able to be deposited by thermal evaporation, can thus integrate with top-emitting organic light-emitting diodes (OLEDs) directly. As a result, the top-emitting OLEDs exhibit reduced angular dependence of emission spectra; for example, the color coordinates is only slightly shifted from (0.2891, 0.6001) to (0.2735, 0.5617) when the viewing angle increases from 0° to 80°.     

CSD-a new unified threshold metric of evaluating LCD viewing angle by color saturation degradation

Lower luminance contrast ratio and chromatic changes affect the visual performance (i.e. color shift) of a thin-film transistor liquid-crystal device (TFT-LCD) at large viewing angles. The de facto method of defining viewing angle, contrast ratio of luminance, fails to represent the substantial visual performance viewed at a larger angle. We found the degradation of color saturation, dS*/d/spl theta/, to be an appropriate metric to aid the conventional viewing angle definition (CR /spl ges/ 10). We empirically determined the threshold for defining the color viewing angles of TFT-LCDs, CVA = {/spl theta//spl par/dS*/d/spl theta/| /spl les/ 0.03}, which reflects the variation not only in chromaticity but also in luminance. The proposed metric was evaluated by psychophysical experiments, whose results validate the efficacy of the proposed metric.     

Highly enhanced light extraction from organic light emitting diodes with little image blurring and good color stability

We report a highly enhanced light extraction from a top emission organic light emitting diode with little image blurring and color variation with viewing angle. Direct integration of a high refractive index micro lens array on the top of the transparent indium zinc oxide top electrode of a green phosphorescent OLED showed a significant enhancement of light extraction to get EQE of 44.7% from 27.6%, the power efficiency of 134.7 lm/w from 85.9 lm/W and the current efficiency of 217.2 cd/A from 120.7 cd/A without image blurring. In addition, the device showed excellent color stability on viewing angle with Commission Internationale de l’Eclairage (CIE) coordinate of Δx = 0.01, Δy = 0.01 as the viewing angle varied from 0° to 60°.     

应用纵向分区彩虹全息术合成断层图像的三维消色像

报道了应用纵向分割多狭缝曝光彩虹全息术合成多幅断层图像为三维消色像的方法及其实验结果。通过将主全息图记录狭缝按纵向分割并结合使用循环分割和色散补偿光栅 ,实现了在较高的分辨率和较低色模糊的多幅断层像的白光三维消色像的合成 ,并提高了再现像的视觉亮度、视场和立体感。     

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.     

光配向技术在液晶电视面板中的应用

采用UV~2A技术的像素较之MVA,其穿透率可以提升20%,这意味着UV~2A技术可以大幅度降低系统功耗及背光成本。采用光配向技术,开发了165cm(65in)UHD液晶面板,其具备出色的显示性能,比如全视角,更快的响应时间,超高的对比度等等。采用Cs-Swing八畴技术,进一步降低了色偏现象。采用网状结构的Cs线设计,降低了其电阻电容信号延迟。开发了一种新型的hG-2D像素结构及其驱动电路,解决了65in UHD面板在120 Hz驱动下充电时间严重不足的难题。     

硫系玻璃薄膜封装层对OLED寿命的影响

在高真空条件下(3×10-4Pa),利用硫系玻璃(Se,Te,Sb)薄膜封装材料对有机电致发光器件(OLED)进行原位封装,有效避免了传统封装方法难以避免的水、氧危害,以达到延长器件寿命的目的。实验对比了正常封装与增加Se、Te、Sb薄膜封装层后器件的性能,对比实验中封装过程都未加干燥剂。研究发现Se、Te、Sb薄膜封装层分别可以使器件的寿命延长1.4倍,2倍,1.3倍以上;采用封装层对器件的电流-电压特性、色坐标等光电性能几乎不产生影响,但影响了器件散热,薄膜封装层使器件的击穿电压、最高亮度等参数稍有下降。