A novel method to measure the cell gap and pretilt angle of a reflective liquid crystal display

A powerful method for the phase retardation measurement of a reflective liquid crystal cell is presented. The proposed method is based on the heterodyne interferometer theory for probing cell parameters. Due to common-path optical arrangement, a fast measurement with high accuracy and sensitivity was possible. Both theoretical analysis and experimental procedures are presented. The experimental results agree well with that obtained theoretically.     

液晶显示器用玻璃微珠的研制

论述了液晶显示器（ＬＣＤ）用玻璃微珠的研制工艺。着重介绍了制造该类玻璃微珠的无碱玻璃、成珠工艺及微珠的精选分级的原理及工艺技术。     

Mathematical model of light propagation through liquid crystal display working under real conditions

The main aim of our work is to present a theory of light propagation through a liquid crystal display worked out in our University. This theory takes into account real conditions of a display operation such as temporal coherence of light source, interference phenomena, spectral characteristics of refractive coefficients of individual layers and their complex forms, real directions of ordinary and extraordinary wavevectors into each layer, real directions of light polarization into anisotropic or dichroic layers etc. Therefore, our theory can be used to determine optical parameters of a liquid crystal display operating under real or at least quasi-real conditions. Contrary to other theories (e.g., Beremann or geometric optics approximation), this model is characterized by a small number of simplifications. Thus, it can be used to analyse a display operating in special conditions, such as military or out-door applications. In these cases, very high optical parameters (luminance and contrast ratio) aare needed. Application of even small simplifications conducts to significant changes of calculated parameters.     

液晶显示器用导电粉的扫描电镜图像

液晶显示器用导电粉的形状、尺寸及偏差对于液晶显示屏的质量控制来说是非常重要的。论述了液晶显示器(LCD)用导电粉的作用和性能要求。给出了液晶显示器用导电粉的扫描电镜图像。该图像对观测导电粉的粒径分布、导电粉在导电点中的浓度和分析导电点缺陷、提高液晶显示器的产品质量具有一定的意义。     

Phase shifting grating-slit test utilizing a liquid crystal display

A quantified focal plane testing method, termed phase-shifting grating-slit test, is demonstrated by utilizing a micro liquid crystal display. In contrast to the setup in the Ronchi Test, an incoherent illuminating grating is used and an optical slit is located at the image plane of the tested lens to modulate the aberrated wavefront. With the micro liquid crystal display generating and phase shifting the incoherent illuminating grating with variable frequency, a higher measurement dynamic range can be achieved on demand.     

Low voltage transflective blue-phase liquid crystal display with a non-uniform etching substrate

A transflective polymer-stabilized blue-phase liquid crystal display(BP-LCD) with a non-uniform etching substrate is proposed.In-plane switching(IPS) electrodes on the bottom substrate are put on the different gaps,and the bottom substrate between the electrodes is etched into different depths in transmissive(T) and reflective(R) regions.This structure can balance the optical phase retardation in the two regions and is helpful to achieve well-matched voltag-dependent transmittance and reflectance curves.This transflective display has high optical efficiency,a wide viewing angle,and low operating voltage(approximately 6 V).     

基于液晶空间光调制器的全息显示

在传统的纯相位全息显示系统中, 一般基于快速傅里叶变换(FFT)算法来计算相位全息图, 在FFT的计算中需要遵循Nyquist采样定理, 因此, 重建图像的尺寸往往受限于空间光调制器的固定采样率. 这个限制可以通过卷积算法或者两步菲涅耳衍射算法来解决, 但是需要使用多个FFT的计算, 导致计算量增大. 鉴于此, 提出了一种基于透镜的纯相位全息图计算方法. 在全息图的计算中, 通过透镜的成像原理建立一个采样率可变的虚拟全息面, 通过调节相应的距离参数使得在全息图的计算中可以任意调节原始图像的采样率, 摆脱了传统方法中液晶空间光调制器带宽积对重建图像尺寸的限制, 并且这种算法只需使用一次FFT就能达到变采样率的衍射计算, 大幅提高了全息图的计算速度. 数值模拟及光学实验结果证明了此方法可以在全息显示光学系统中清晰地重建不同尺寸的图像. 同时该系统可以有效地消除由空间光调制器的像素化结构带来的零级衍射.     

液晶电光特性研究

随着近几年液晶显示技术在诸多领域的广泛应用和新技术的推出,人们一直致力于改善液晶器件显示性能的研究。在液晶显示器应用中,电光特性是一个很重要的参数,介绍了采用激光测量的方法获得液晶的电光特性、阈值电压及视角特性。分析了液晶分子在交流电场作用下重新取向后的扭曲特性,测试了不同电压下液晶分子的透光率和扭曲角度,结果表明:该方法是可行的,向列相液晶具有0.92 V较低阈值电压和较为陡峭的电光曲线,水平方向上在-60~+50有较好的视角特性,垂直方向上在-40~+20有较好的视角特性。该结论为偏光器件的设计与制作提供了依据。     

用于彩色液晶显示器的色分离光栅的优化设计

利用光栅实现液晶显示器中的色分离可以提高液晶显示器对光能的利用率。为了提高光能利用率,对光栅台阶数进行了优化设计,经矢量衍射理论计算,优化后的多台阶色分离光栅的能量利用率达到了65.3%,与采用滤色片的方法相比,光能利用率提高了近一倍;与三台阶相比,光能利用率提高了9.3%。     

Liquid crystal Fresnel lens display

A novel see-through display with a liquid crystal lens array was proposed.A liquid crystal Fresnel lens display(LCFLD) with a holographic screen was demonstrated.The proposed display system has high efficiency,simple fabrication,and low manufacturing cost due to the absence of a polarizer and color filter.     

液晶光阀光导纤维显示管

利用光导纤维与ＣＲＴ相结合的技术，产生高清晰度图像字符信息启动液晶光阀，在外光源的照射下，投影得到高清晰度、高亮度图像。     

透反区响应时间相等的双盒厚透反液晶显示器

提出了一种透反区响应时间相等的双盒厚透反液晶显示器。该透反液晶显示器在透射区采用了强锚定能边界条件,以缩短其响应时间;在反射区采用了弱锚定能边界条件,以增加其响应时间;采用过压驱动技术,使透反区的响应时间相等。分析了该透反液晶显示器的结构和原理,设计了透射区和反射区的边界锚定能,计算了响应时间和电光特性,得到了透反区响应时间相等,且具有良好电光特性的双盒厚透反液晶显示器。     

Optical simulation of in-plane-switching blue phase liquid crystal display using the finite-difference time-domain method

The finite-difference time-domain method is used to simulate the optical characteristics of an in-plane switching blue phase liquid crystal display.Compared with the matrix optic methods and the refractive method,the finite-difference timedomain method,which is used to directly solve Maxwell's equations,can consider the lateral variation of the refractive index and obtain an accurate convergence effect.The simulation results show that e-rays and o-rays bend in different directions when the in-plane switching blue phase liquid crystal display is driven by the operating voltage.The finitedifference time-domain method should be used when the distribution of the liquid crystal in the liquid crystal display has a large lateral change.     

Texture evolution of cholesteric liquid crystal driven by a thermal process

Cholesteric liquid crystal displays (Ch-LCDs) have potential as screens in portable readers. In the present study, it is demonstrated that a Ch-LCD can be driven by a thermal process at a temperature of 90 °C. At a suitable temperature, the texture of the cholesteric liquid crystal will be transfrred from planar to focal conic. The experimental results show that the reflectance of a Ch-LCD is influenced by texture after the thermal process. After thermal treatment at 90 °C, the periodicity was reduced from 63 nm to 55 nm. A chain tilting angle of ∼29° was estimated.     

彩色全息显示中液晶空间光调制器位相调制偏差的矫正方法

采用三基色激光照明并结合时分复用或空间复用技术,可实现基于液晶空间光调制器(LC-SLM)的彩色全息显示.但由于在不同激光波长入射条件下LC-SLM的位相调制特性曲线不同,难以同时满足多波长入射条件下2π线性位相调制的要求,致使彩色全息再现结果受到共轭像和零级斑的干扰.针对该问题,本文通过实验测试获得LC-SLM在不同波长入射时的位相调制特性曲线,并分析了RGB激光器各分量的位相调制特性曲线非线性偏差和调制幅度偏差对多阶位相型傅里叶变换相息图再现效果的影响.根据"查表法"建立了各波长入射条件下满足2π线性位相调制的灰度映射关系,并对RGB分量相息图进行修正.通过对修正前后RGB分量相息图的数值模拟再现和光电再现实验与分析,结果表明:该方法有效地克服了LC-SLM位相调制特性曲线偏差的不利影响,从而改善了彩色全息显示中各分量相息图的再现质量.     

基于LED背光源区域控制的高动态范围液晶显示技术进展

传统液晶显示器的背光源采用恒定亮度的面光源,由于漏光现象限制了液晶显示器对比度动态范围的提高。采用LED背光源区域控制实现高动态范围(HDR)液晶显示的技术不仅可获得高对比度、宽色域的液晶显示效果,而且可以有效地降低系统功耗。在对实际区域控制技术算法流程中背光驱动信号的获取、背光强度分布及液晶屏幕信号补偿三个方面所采用的不同方法进行了概述。论述了当前国内外LED背光源显示器件的进展。     

平行排列丝状液晶在超短脉冲激光激励下发生瞬态扭曲形变的最佳偏振角

利用光学相位延迟法，观察到平行排列丝状液晶在超短脉冲激光（10ns）激励下的瞬态扭曲形变.实验结果表明，虽然脉冲激光的电场强度远远大于液晶发生扭曲形变的阈值，但并不能保证液晶会发生瞬态扭曲形变.这主要是因为脉冲激光的激励时间非常短，而液晶分子发生扭曲形变的响应时间相对较长，从而使其来不及形变.分析发现：激励激光的偏振方向与平行排列丝状液晶分子的最佳夹角是45°.利用此条件，观察到掺微量D型苏氨酸卟啉的平行排列丝状液晶在超短脉冲激光激励后具有记忆效应，这在光存储和记忆显示方面有很大的实用价值.     

Ultra slim and bendable backlight system with a unified component for liquid crystal display applications

Our research group has developed an ultra slim and bendable backlight system, which was manufactured by a continuous roll-to-roll process, with a unified component for liquid crystal display (LCD). This backlight system, which has a thickness of 0.26 mm, is simply composed of a light guide film and an optically patterned film made of photocurable resin with micro particles, consequently it does not require any additional optical films such as prism sheets or diffuser. In addition, we have developed a new light guide component which is composed of bundled optical fibers in order to collimate light from the light source to the light guide film. We found that the backlight system could be radiated uniformly across the LCD surface whether plane or curved, and we were able to realize an advanced LCD with good flexibility, high efficiency and high productivity.     

手机液晶显示器的黑白图案反转

根据液晶分子扭转排列特性,指出了光在液晶中的偏振方向扭转的角度与光在液晶中的传播距离有关,较好地解释了旋转手机液晶显示器的黑白图案反转现象.