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1.
    
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   

2.
    
Abstract— Liquid‐crystal displays (LCDs) have notable variation in luminance and perceived contrast as a function of the angle from which they are viewed. Though this is an important performance issue for LCDs, most evaluation techniques for assessing this variation have been limited to laboratory settings. This study demonstrates the use of a photographic technique for such an evaluation. The technique is based on an actively cooled charge‐coupled‐device (CCD) detector in combination with a macro lens covering a circular angular range (θ) of ±42.5°. The camera was used to evaluate the luminance and perceived contrast properties of an LCD. Uniform field images corresponding to 17 equally spaced gray‐scale values in the digital driving level (DDL) range of the display system were acquired. The 12‐bit gray‐scale digital images produced by the camera were converted to luminance units (cd/m2) via the measured luminance vs. DDL response function of the camera. The changes in perceived contrast as a function of viewing angle were derived from the Barten model of the gray‐scale response of the human‐visual system using the methods proposed by the AAPM TG18 Report. The results of this photographic technique were compared to measurements acquired from a similar display using a Fourier‐optics‐based luminance meter. The results of the two methods generally agreed to within 5%. The photographic methods used were found to be accurate and robust for in‐field assessment of the angular response of LCDs over the FOV of the camera.  相似文献   

3.
    
Abstract— A viewing‐angle‐controllable liquid‐crystal display (LCD) is proposed. When the device is only driven by an in‐plane electric field, it exhibits a wide‐viewing‐angle (WVA) mode. And it exhibits narrow‐viewing‐angle (NVA) mode when it is driven by a vertical electric field as well as an in‐plane electric field. In this manner, the viewing angle of the device can be controlled from 100° to 30°. The device exhibits a good viewing‐angle‐controlling characteristic and high transmittance.  相似文献   

4.
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   

5.
    
Abstract— A continuous‐viewing‐angle‐controllable liquid‐crystal display (LCD) using a blue‐phase liquid crystal is proposed. To realize both wide‐viewing‐angle (WVA) mode and narrow‐viewing‐angle (NVA) mode with a single liquid‐crystal panel, each pixel is divided into a main pixel and a subpixel. The main pixel is for displaying images in both modes. The subpixel is for displaying images in WVA mode and controlling the viewing angle in NVA mode. The device exhibits a good viewing‐angle‐controlling characteristic and high transmittance.  相似文献   

6.
    
Abstract— In this paper, we present results from a new liquid crystal over plastic printed thin‐film‐transistor (TFT) display. The display demonstrator shows that the processing incompatibilities between the plastic TFT backplane and the liquid‐crystal materials can be addressed to make a stable twisted‐nematic structure. New fabrication processes such as the photo‐alignment of liquid crystals have made it possible to create a new generation of displays, which pave the way towards fully integrated plastic liquid‐crystal‐display technologies.  相似文献   

7.
    
Abstract— Viewing‐angle dependences of the contrast ratio and color shift of LCDs have been radically improved as evidenced by the increasing application of LCDs in high‐quality television. This paper describes the concept of optical compensation and the fundamental characteristics of the viewing‐angle property for various LC modes.  相似文献   

8.
    
Abstract— A multistable liquid‐crystal device has been realized in this study; its smectic‐A LC is oriented by in‐plane and out‐of‐plane electric fields with various amplitudes. This paper introduces improvements made to electrode structure and hybrid surface treatments that have enhanced SmA LC device performance. The driving voltage of the hybrid‐aligned cell has been reduced to 20% of the vertical‐aligned one, and light leakage has been suppressed by out‐of‐plane electric‐field‐strength modulation. The many advantages of this multi‐stabilized LC device could be applied to memory devices and to flexible displays.  相似文献   

9.
    
Abstract— In this paper the operational principle and performance of guest‐host, liquid‐crystal/polymer‐composite scattering, and cholesteric liquid‐crystal reflective displays are reviewed. These displays do not use polarizers and have the advantage of providing high reflectance and compatibility with flexible plastic substrates.  相似文献   

10.
    
Abstract— Techniques to reduce LCD motion blur are extensively used in industry and they depend on an inherent LCD parameter: response time. However, normative response time is not a sufficient reference to improve LCD performance and all the gray‐to‐gray response‐time quantities are required to obtain good improvement. However, measuring and gathering all the gray‐to‐gray transitions takes an excessive amount of time. Consequently, we propose a novel LCD model to simulate as well as compute gray‐to‐gray transitions (response time and behavior) from a reduced measurement set in order to decrease the response‐time measurement.  相似文献   

11.
    
Abstract— Although the common twisted‐nematic liquid‐crystal displays (TN‐LCD) has excellent contrast and low color dispersion, it suffers from small viewing angle when driven into the homeotropic state. Among the many techniques proposed, in‐plane switching (IPS) has been quite effective in improving viewing angle. However, there may be difficulty in adopting conventional IPS to higher‐definition displays because it suffers from limited storage capacitance and reduced transmittance. A new comb‐on‐plane switching (COPS) electrode design is proposed. Compared to conventional IPS, COPS allows for lower switching voltage and offers advantages including naturally scalable storage capacitance, wide viewing angle with TN‐like high transmittance, and low color dispersion.  相似文献   

12.
    
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   

13.
    
Abstract— Two newly derived characterization models for a liquid‐crystal (LC) display have been tested for five LC‐based displays. Data measured from a series of test colors indicated that all LC‐based displays showed similar characteristics, including an S‐shaped tone curve and poor channel chromaticity constancy. Because they include a hyperbolic function in their definition, the models do not have analytical inverses, and so iterative mathematical techniques are applied. It was shown that a new characterization model based on a hyperbolic function fits the tone curve very accurately with only four coefficients per channel for any type of LCD. In addition, it was also shown that the first derivative of the function provides a means of accurate correction of the chromaticity variation.  相似文献   

14.
    
Abstract— An analytical model of an LCD cell under gravity and local loading to prevent permanent deformation of the photospacers and the occurrence of gap mura will be presented. The analytical model is established from the Winkler model, which is composed of a beam and a series of springs. The analytical solutions have been simplified under specific assumptions and modified through three‐dimensional simulations in order to improve their accuracy. Therefore, the analytical model can be applied to the design of an in‐cell touch panel while considering the local loading due to touch or probe testing and contact conditions of photospacers. This analytical model can be used to provide instant design criteria for photospacers without considerable simulation and experimental data and to enhance the reliability of the LCD cell structure.  相似文献   

15.
    
Abstract— A fast‐response and wide‐view liquid‐crystal display (LCD) using the crossed fringe‐field‐switching (CFFS) mode is proposed, where the fringe‐field electrodes exist on both the top and bottom substrates. The bottom fringe field is used to turn on the LC directors and the top fringe field is used to assist in the LC decay process. The decay time is reduced by ～2× compared to that of the conventional FFS mode between the full bright and dark states, and more than a 2× improvement is obtained for other gray‐scale transitions. This CFFS mode also preserves the wide‐view characteristics as the conventional FFS mode. Its applications to LCD TVs and monitors for reducing image blur are addressed.  相似文献   

16.
    
Abstract— Field‐sequential‐color technology eliminates the need for color filters in liquid‐crystal displays (LCDs) and results in significant power savings and higher resolution. But the LCD suffers from color breakup, which degrades image quality and limits practical applications. By controlling the backlight temporally and spatially, a so‐called local‐primary‐desaturation (LPD) backlight scheme was developed and implemented in a 180‐Hz optically compensated bend (OCB) mode LCD equipped with a backlight consisting of a matrix of light‐emitting diodes (LEDs). It restores image quality by suppressing color breakup and saves power because it has no color filter and uses local dimming. A perceptual experiment was implemented for verification, and the results showed that a field‐sequential‐color display with a local‐primary‐desaturation backlight reduced the color breakup from very annoying to not annoying and even invisible.  相似文献   

17.
Abstract— The primary goal of this study was to find a measurement method for motion blur which is easy to carry out and gives results that can be reproduced from one lab to another. This method should be able to also take into account methods for reduction of motion blur such as backlight flashing. Two methods have been compared. The first method uses a high‐speed camera that permits us to directly picture the blurred‐edge profile. The second one exploits the mathematical analysis of the motion‐blur formation to construct the blurred‐edge profile from the temporal step response. Measurement results and method proposals are given and discussed.  相似文献   

18.
    
Abstract— A color‐filter liquid‐crystal‐on‐silicon (CF‐LCOS) microdisplay that integrates color filters on silicon for color will be presented. The color‐filter process on silicon was optimized to achieve fine resolution and precise alignment of the color filters on the pixel array, good adhesion to the silicon suface, and a flat surface for the liquid‐crystal cell assembly. Important optical and electrical parameters of the color filters were extracted to establish an electro‐optical model of the CF‐LCOS microdisplays for device simulation. Thermal, chemical, and light‐stability characterizations were performed to ensure the stabilty of the color filters and CF‐LCOS microdisplays. With color CF‐LCOS microdisplays already available, the projection or viewing optics is greatly simplified. This CF‐LCOS microdisplay is ideal for near‐to‐eye displays because of its low‐power consumption and compactness. The CF‐LCOS microdisplay could also withstand medium light illumination for medium‐sized projectors. A single‐panel projector based on one CF‐LCOS microdisplay of 1280 × 768 × RGB resolution was demonstrated.  相似文献   

19.
    
Abstract— The color performance, including color gamut, color shift, and gamma curve, of a multi‐domain vertical‐alignment (MVA) liquid‐crystal display (LCD) using an LED backlight are calculated quantitatively. Simulation results indicate that an LED backlight exhibits better angular color uniformity and smaller color shifts than a CCFL backlight. Color gamut can be further widened and color shift reduced when using a color‐sequential RGB‐LED backlight without color filters, while the angular‐dependent gamma curves are less influenced using different backlights. The obtained quantitative results are useful for optimizing the color performance and color management of high‐end LCD monitors and LCD TVs.  相似文献   

20.
Abstract— The dynamic performance of displays is an important characteristic for multimedia applications. Motion‐picture response time (MPRT) has been used as an indicator of the dynamic performance of LCDs. This paper describes a comprehensive method of MPRT evaluation for the oblique viewing direction. By using a tilted camera configuration, the angular dependency of MPRT is investigated for the condition that the horizontally scrolling patterns are observed from the vertical direction. For each gray‐to‐gray transition, distinct changes in MPRT and the luminance profile of blur are observed.  相似文献   

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