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1.
    
Abstract— By using a new pixel design and a novel driving scheme that adds a bias electrode and a bias TFT to the ordinary pixel structure, a high‐contrast‐ratio and wide‐viewing‐angle LCD mode, refered to as the biased vertical‐alignment (BVA) mode, has been sucessfully developed. Compared to the published data on the PVA and MVA modes, the BVA mode has a distinct advantage of lower manufacturing cost due to the elimination of a lithographic process step that forms either ITO cuts or protrusions on the color‐filter substrates. The BVA mode requires ITO cuts on the TFT substrate similar to that for the PVA and MVA modes. The 15‐in. BVA‐mode XGA prototype exhibits a high contrast ratio of 1200:1 and high cell transmittance of 4.3%.  相似文献   

2.
    
Abstract— The recent development of polymer‐induced pretilt angle in multi‐domain vertical‐alignment liquid‐crystal (LC) structures is reviewed. To create a small but well‐defined pretilt angle, ～0.1 wt.% of a photo‐curable monomer was mixed in an LC host and a bias voltage was applied to reorient the LC directors within each domain. The monomers are polymerized near the substrate surfaces by UV exposure. The formed polymer layers change the surface pretilt angle of the LC from 90° to about 89° with a defined azimuthal orientation. Consequently, within each domain the LC reorientation direction responding to the external field is well‐defined which leads to faster rise time and higher transmittance. This new technology overcomes the long standing problems of conventional MVA devices and is therefore expected to play a dominant role in the future.  相似文献   

3.
    
Abstract— A single‐cel l‐gap transflective liquid‐crystal display with two types of liquid‐crystal alignment based on an in‐plane‐switching structure is proposed. The transmissive region is almost homeotropically aligned with the rubbed surfaces at parallel directions while the reflective region has a homeotropic liquid‐crystal alignment. For every driving voltage for a positive‐dielectric‐anisotropy nematic liquid crystal, the effective cell‐retardation value in the transmissive region becomes larger than that in the reflective region because of optical compensation film which is generated by low‐pretilt‐angle liquid crystal in the transmissive region. Under the optimization of the liquid‐crystal cell and alignment used in the transmissive and reflective areas, the transmissive and reflective parts have similar gamma curves. An identical response time in both the transmissive and reflective regions and a desirable viewing angle for personal portable displays can also be obtained.  相似文献   

4.
    
Abstract— The surface‐friction characteristics of the post‐bake temperature were compared to that of the rubbing condition on VA‐mode alignment films (AFs) using frictional force microscopy (FFM). The surface roughness and the surface frictional force increased when the temperature was elevated. However, the frictional asymmetry could not be detected by the frictional loop due to the instability of the side‐chain molecular arrangement. For the inter‐influences of the total friction and surface roughness, the density of the side chain was changed and it was intentionally rubbed for evaluation. The results showed that the total friction was higher when the rubbing was stronger and side‐chain density lower, and the surface roughness also increased in the same manner. This can be explained by the potential interaction due to the curved structure of the side‐chain surface that establishes the probe that is scanned and the top surface layer. In order to confirm the influence of the pre‐tilt angle on the tilt of the side chain, a test cell was produced under the same conditions and evaluated. The results showed that the pre‐tilt‐angle decreased according to the difference in density of the side chain and strength of rubbing after injecting liquid‐crystal (LC).  相似文献   

5.
    
Abstract— A measurement method for the determination of the cell parameters of vertically aligned nematic LCOS devices has been developed. It provides the values for the pre‐tilt angle and the cell thickness in a reliable way, without the need for spectroscopic instruments. The method uses oblique incidence to separate the determination of pre‐tilt angle and cell thickness from each other and thus enhance the measurement accuracy. As a bonus, the measurement system consists only of simple optical components and does not need costly instruments.  相似文献   

6.
    
Abstract— The goal of this work is to achieve a better understanding of the electro‐optical characteristics of a VA‐mode full‐HD LCOS panel via simulations and experiments. The optical parameters, such as reflectance, fill factor, and contrast that vary due to the pre‐tilt angle and cell gap, were also studied. Based on the simulations, the optical fill factor was the highest at an angle of 81° and 2.1 μm under the given conditions. The contrast ratio was the highest at an angle of 89° and 2.4 μm. Five different LCOS panels were fabricated; three different angles (85°, 87°, and 89°) at a 2.1‐μm cell gap and two different cell gaps (1.8 and 2.1 μm) at an angle of 87°. The measured reflected light intensity was compared to the calculated reflectance. The simulated and measured contrasts were compared with each other. The simulation results well‐matched the experimental results and the differences were less than a few percentage points. Based on the comparative studies on reflectance and contrast, the test panel under the condition of an 87° angle and 2.1‐μm gap showed the best performance results.  相似文献   

7.
采用聚合相分离方法制备环氧树脂基PDLC膜.通过对液晶含量、固化温度和时间等条件进行优化,研究上述条件对PDLC膜性能的影响;使用UV-Vis、AFM、SEM等方法对聚合物的物理特性和PDLC膜的光电性质做了深入探讨.PDLC膜在传感器、光电开关、光栅以及新型分析仪器元器件等方面具有广阔的应用前景.  相似文献   

8.
液晶化学传感器是一种基于液晶分子排列取向发生变化来检测目标物存在与否的化学检测新装置。对液晶化学传感器的制备方法与应用进行了综述,并对该领域的发展方向进行了展望。  相似文献   

9.
    
A new liquid crystal display device with fast response time, high transmittance, and low voltage for virtual reality is reported. When driven at 90 Hz with 17% duty ratio, the motion picture response time is 1.5 ms, which is comparable with cathode‐ray tube, leading to indistinguishable motion blur. Moreover, this device enables high‐resolution density because only one thin‐film transistor per pixel is needed and it has a built‐in storage capacitor.  相似文献   

10.
    
Abstract— A polymer‐dispersed liquid‐crystal (PDLC) matrix template embedded with nano/microparticles can be backfilled/infiltrated with a dye‐doped liquid crystal for a paper‐like reflective display. In this way, a desirable degree of diffusion can be realized to reduce the viewing‐angle dependency of a gain reflector and metallic glare without changing other electro‐optical properties.  相似文献   

11.
    
Abstract— A novel liquid‐crystal alignment method, diamond‐like carbon and ion beam alignment (DLC/IB) technology, was announced at the 2001 SID Symposium. And since December 2001, a new‐generation ion‐beam machine has been placed into the manufacturing line of IDTech. DLC/IB technology is mainly used for medical displays, which require a monochrome high‐density and super‐uniform display. We report on the latest developments of these advanced monochrome displays.  相似文献   

12.
    
A novel nematic liquid crystal (LC) technology‐based electronically controlled leaky wave antenna (LWA) with microstrip‐waveguide conversion working mechanism and wide beam steering range is presented in this article. The LWA is a combination of an inverted microstrip structure and rectangular waveguide. According to the characteristics of LC materials in microwave band, a broadband microstrip‐waveguide conversion device is proposed. The gradient slot leaky wave structure is combined with the microstrip‐waveguide conversion device to form an electronically controlled LWA with continuous tunable beam. Simulation and experiment results show that the LWA proposed in this article has a 32° beam scanning range at 12 GHz and good impedance matching and stable gain, suggesting the great potential of nematic LC materials for extensive applications in microwave band in the future.  相似文献   

13.
    
A proposed pixel structure named ‘Sub-pixel Electrode Shielding (SES)’ is developed to improve the transmittance of eight-domain vertical alignment  liquid crystal display (LCD). In the SES pixel, the sub pixel electrode is designed to partially overlap with data line and encircle the main pixel to shield the effects of data signal on the common signal. Therefore, the array common electrode and data signal shielding lines of conventional pixel can be removed to enhance the aperture ratio. Results show that the 65 inch ultra-high-definition (UHD) LCD panel with this proposed SES pixel design achieves a transmittance of 5.9%, which is 7.3% higher than the panel with conventional pixel design, and shows the same viewing angle characteristic as the conventional one.  相似文献   

14.
    
Abstract— The solid‐surface/liquid‐crystal interactions, defining the field‐free alignment of the liquid crystal in conventional liquid‐crystal displays, are playing a vital role in their optical appearance and performance. Nano‐scale changes in the solid‐surface structure induced by light have been recently shown to affect the anchoring strength and the easy‐axis direction. Fine tuning of the anchoring strength is also demonstrated by nano‐structuring of the Langmuir‐Blodgett monolayer employed as liquid‐crystal alignment layers promoting homeotropic orientation. On the basis of nano‐engineering of the surface alignment properties, two novel alignment concepts have been introduced: electrically commanded surfaces (ECS) and high‐performance alignment layers (HiPAL). Nano‐structured polymers related to these concepts have been designed, synthesized, and used as materials for alignment layers in LCDs. ECS materials belong to the category of active alignment materials designed to mediate switching of the liquid crystal, whereas the HiPAL materials make possible the control of the molecular tilt angle in a broad range, from 0° to 90°, and they seem to enable the control of the anchoring strength as well. The nano‐structured alignment materials are strong candidates for implementation in a new generation of advanced liquid‐crystal displays and devices.  相似文献   

15.
    
Abstract— A plasma‐beam process, developed for the alignment of liquid crystals (LC) in electro‐optic applications, has been successfully applied to align “non‐standard” LC, such as crystalline materials with LC phases at elevated temperatures and reactive mesogenes. In addition to the high alignment quality of the materials, there is no need for an intermediate layer between the substrate and the LC layer. Furthermore, the construction of our source simplifies the alignment procedure of large‐area rigid substrates and the roll‐to‐roll processing of flexible films. This method opens new horizons for optical retarders and polarizers, as well as anisotropic semiconducting films for organic electronics.  相似文献   

16.
    
In this paper, we propose a liquid prism based on electrowetting‐on‐dielectric and gravity effect. The device is filled with two immiscible liquids. The conductive liquid is filled in the upper part of the device, and the oil is filled in the bottom of the device. Different from the conventional liquid prism, the density of the conductive liquid is larger than that of the oil. The liquid–liquid interface can form a tilt shape when applied different voltages to the opposite sidewalls. The beam will be deflected when the light passes through the device. Our results show that the tilt angle of the liquid–liquid interface is ~45°, and the light beam can be deflected by 22.2° (?10.9° to +11.3°). The actuation time of the device is ~240 ms. The proposed liquid prism for light beam steering and tracking has potential application in laser directions, telecommunications, and scanners.  相似文献   

17.
The electrospray deposition (ESD) method is an established film‐forming technique. To control the pretilt angle on films, we developed two novel ESD methods for spraying two kinds of solutions containing alignment materials. One method is a simultaneous spraying method, while the other is a time‐divided spraying method. When we used the simultaneous‐spraying ESD method, we observed numerous fine liquid crystal (LC) domains with a diameter of approximately 10 µm in the LC cell. These LC domains were substantially smaller than those of LCs fabricated using the conventional ESD method. However, the pretilt angle could not be controlled over a wide range because multiple parameters could not be simultaneously controlled to achieve a stable spray. Using the time‐division ESD method, we controlled the pretilt angle over a wide range from 5° to 40°, with tiny domains. As a demonstration, we fabricated a 270° super‐twisted nematic mode cell using this method.  相似文献   

18.
    
Abstract— The mechanisms of photochemical reactions occurring during the operation of LCOS panels under intense illumination are analyzed. Regardless of the liquid‐crystal‐mixture formulation, light may generate radicals in the liquid crystal and the polyimide alignment layer. The interaction of these radicals modifies the PI surface and causes alignment degradation. Using kinetic equations for these processes, a lifetime model for the LCOS panels is developed. This new model of lifetime dependence versus light intensity is found to be in agreement with experimental data. This model verifies the TN LCOS panel lifetime to be in excess of 50,000 hours for RPTV applications.  相似文献   

19.
    
Abstract— The plasma‐beam alignment procedure earlier developed for the alignment of nematic liquid crystals is successfully extended to ferroelectric liquid crystals (FLC). The highly uniform alignment of the “chevron” structure (before electrical treatment of FLC cells) and “quasi bookshelf” structure (after the electrical treatment) are realized. The contrast of bistable switching larger than 350:1 is achieved. This makes the non‐contact plasma‐beam alignment procedure especially attractive for high‐contrast bistable LCDs on an LCOS base, particularly used in PDA and e‐books. Fast switching and realization of gray scale in the plasma‐beam aligned FLC cells makes this technique also promising for full‐color displays including color LCD TV.  相似文献   

20.
We have developed a new microstructure film for wide viewing liquid crystal displays (LCDs). By attaching it to the surface of a conventional LCD, the viewing angle characteristics of LCD has drastically improved without causing a blur of the frontal image and a decrease in the contrast ratio under bright ambient light conditions. This film can be applied to various LC modes including twisted nematic and multidomain vertical alignment by changing its internal micrometer‐size 3D structure. Further, this film can be mass‐produced efficiently by self alignment roll‐to‐roll process.  相似文献   

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