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.     

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。     

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。     

自组装法制备新型液晶垂直取向膜

用硅烷偶联剂3-氨丙基-三乙氧基硅烷,通过自组装反应在石英基板表面制备了含有二苯乙炔基的自组装单层膜。用该自组装膜作为向列相液晶的取向层制成液晶器件,在偏光显微镜下观察,发现向列相液晶获得了均匀、稳定的垂直取向效果。热稳定性试验表明,用自组装方法制备的液晶垂直取向膜有良好的热稳定性,在250℃条件下取向仍可保持。     

聚酰亚胺单体配比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,目前文献大多研究聚酰亚胺结构对液晶预倾角的影响,而单体配比对预倾角影响的研究还较少。文章用均苯四羧酸二酐(PM-DA)、4,4′-二氨基二苯甲烷(MDA)和4-(4-(三氟甲氧基)苯甲酰基)环己基-3,5-二胺基苯甲酸酯(TBCA)制备了一系列三元共聚型聚酰亚胺液晶取向剂,用原子力显微镜对取向剂诱导液晶分子取向能力进行了考察,首次研究了单体配比对液晶预倾角的影响。研究发现,所有取向剂对液晶分子均有较好的取向性能;液晶分子的预倾角随TBCA含量增加而增大;在保持两种二胺配比不变的情况下,随着二酐含量增加而先增大后减小。并最终在单体配比为n(PMDA)∶n(MDA)∶n(TBCA)=104∶60∶40的条件下,合成了一种预倾角高达7.7°、成本较低的聚酰亚胺液晶取向剂。     

聚酰亚胺制备条件对液晶预倾角的影响

液晶取向层性能优劣直接影响液晶分子在基板表面的排列效果,进而影响液晶显示器的光电性能,因此是制造液晶显示器的关键材料之一。文献大多研究聚酰亚胺结构对液晶预倾角的影响,而加料顺序对预倾角影响的研究,迄今还未引起注意。文章用均苯四酸二酐(PMDA)、4,4′-二胺基二苯甲烷(MDA)和具有较大支链的4-(4-(三氟甲氧基)苯甲酰基)环己基-3,5-二胺基苯甲酸酯(TBCA)等单体制备聚酰亚胺(PI),首次研究了单体加料顺序对液晶预倾角的影响,同时也研究了二胺配比对液晶预倾角的影响问题,并探讨了预倾角的热稳定性等问题。实验发现:先将PMDA加入TBCA的NMP溶液中,待PMDA完全溶解后,再加入MDA继续反应2 h,可得到预倾角为4.1°的聚酰亚胺液晶取向剂,且液晶盒在120℃下保持4 h后预倾角没有明显变化,预倾角稳定性良好。     

一种新型光敏小分子用于光控取向的研究

通过在3,5-二羟基苯甲醇分子中的双酚基基团上引入双肉桂酰酯光敏基团的酯化反应,合成了一类新型的分子顶部为羟基极性基团,整个分子构型类似于树枝状的光敏小分子化合物。将此种光敏材料配成一定浓度的溶液,旋涂在玻璃基板上成膜,经过线性偏振紫外光辐照后发生交联反应,制备成光控取向膜。以此种取向膜制成向列相液晶的平行液晶器件,在偏光显微镜下观察,发现取得了均一、稳定的取向效果,并且该取向膜具有良好的热稳定性能。     

Au纳米颗粒对向列相液晶取向性能的影响

液晶分子的初始排列在液晶显示器中起着关键的作用。纳米粒子掺杂到液晶体系可扰乱液晶分子的排列,从而改变液晶的自组装特性,进而影响液晶的各项性能。将制备的Au八面体纳米颗粒掺杂到向列相液晶4-氰基-4′-正戊基联苯(5CB)中,灌入液晶盒后,通过使用偏光显微镜对液晶盒的观察发现,掺杂的八面体Au纳米颗粒诱导5CB液晶分子发生了垂直取向,而球形Au纳米颗粒不能诱导液晶分子垂直取向。这归因于八面体Au纳米颗粒的表面能比较小,液晶分子间的作用力比较大,使液晶分子易于垂直取向。随着O-Au NPs的浓度增大,液晶分子的取向效果先变好又逐渐变差。这是因为O-Au NPs的浓度越高,可诱导越多的液晶分子垂直取向排列,但随着纳米粒子浓度的增加,纳米粒子团聚,减少了与液晶分子的作用,使取向效果变差。动态过程实验显示,0.1%的八面体金纳米颗粒可诱导向列相液晶5CB在2 min内快速完成垂直取向,表明O-Au NPs具有优异的诱导5CB取向的动态效果。     

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。     

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。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.