Single Gamma Curve Research Articles

Transflective liquid crystal display using regular flat square electrodes

ABSTRACT A single-cell-gap vertical alignment transflective liquid crystal display with flat square indium tin oxide electrodes is proposed. The proposed structure makes the best of the intrinsic fringe electric field between the flat square electrodes in each pixel to control the liquid crystal directors to match the optical path difference between the transmissive and reflective regions. Simulation results show that the display exhibits a reasonably high contrast ratio, low operating voltage, and symmetrical viewing angle. Moreover, the voltage-dependent transmittance and reflectance curves overlap well, which enables a single gamma curve driving.

Refraction effect in an in-plane-switching blue phase liquid crystal cell

We develop a refraction model to analyze the electro-optic effects of an in-plane-switching blue phase liquid crystal (IPS-BPLC) cell. Good agreement with experiment is obtained. Based on this model, we optimize the parameters affecting the electro-optics of IPS-BPLC, such as electrode dimension, saturated induced birefringence, saturation electric field, and cell gap. An IPS-BPLC with low operation voltage (<10V(rms)) and high transmittance (~80%) with single gamma curve can be achieved by optimizing the BPLC material and device structure.

High Performance Negative Dielectric Anisotropy Liquid Crystals for Display Applications

We review recent progress in the development of high birefringence (Δn ≥ 0.12) negative dielectric anisotropy (Δε &lt; 0) liquid crystals (LCs) for direct-view and projection displays. For mobile displays, our UCF-N2 (low viscosity, negative Δε, high Δn) based homogeneous alignment fringe-field switching (called n-FFS) mode exhibits superior performance to p-FFS in transmittance, single gamma curve, cell gap insensitivity, and negligible flexoelectric effect. For projection displays using a vertical alignment liquid-crystal-on-silicon (VA LCOS), our high birefringence UCF-N3 mixture enables a submillisecond gray-to-gray response time, which is essential for color sequential displays without noticeable color breakup. Our low viscosity UCF-N2 also enables multi-domain VA displays to use a thinner cell gap for achieving faster response time.

Fringe-Field Switching with a Negative Dielectric Anisotropy Liquid Crystal

We report a high performance negative dielectric anisotropy (Δe) liquid crystal for fringing field switching (n-FFS) display. We compare the electro-optic characteristics of FFS cells using positive and negative Δe LCs. With comparable driving voltage and response time, the n-FFS cell has advantages in higher transmittance, single gamma curve, less cell gap sensitivity and slightly wider viewing angle. LC director deformation distribution is analyzed to explain these performance differences.

Transflective LCDs With Two TFTs and Single Data Line

A simplified single-cell-gap transflective liquid crystal display with two thin-film-transistors and only one data line is proposed. The simulated voltage-dependent transmittance (VT) and reflectance (VR) curves overlap reasonably well, which enables a single gamma curve driving. The need of only one data line improves the aperture ratio, reduces the fabrication cost, and stabilizes the manufacturing process.

Transflective fringe-field switching liquid crystal display using an embedded wire grid polarizer

A single-cell-gap and single-gamma transflective liquid crystal display (TR-LCD) using fringe-field switching is achieved by an embedded wire grid polarizer. In the proposed TR-LCD, the common electrode is patterned into nano-sized wire grids in the reflective part whereas it remains a plane shape in the transmissive part. The nano-sized wire grids play dual roles as common electrode and reflective polarizer in the reflective part. By optimizing the pixel electrode structures, a single gamma curve for the reflective and transmissive parts is demonstrated. Such a TR-LCD is free from in-cell retarder, compensation film, and additional reflector.

34.4: A Single Cell Gap Transflective LCD with Dual Common Electrodes and Coupling Capacitance

AbstractA single cell gap transflective LCD was developed, using dual common electrodes and a coupling capacitance between the transmissive and the reflective electrodes to obtain a single gamma curve between the reflective and transmissive regions.

P‐142: A Simple Transflective LCD for Mobile Display Applications

AbstractA simple transflective liquid crystal display (TR‐LCD) is proposed based on dual cell gap 63.6° TN/MTN mode. with only one additional positive A‐film, this TR‐LCD configuration achieves good performance for both transmissive (T) and reflective (R) regions: 1) high optical efficiency, 2) low operation voltage, 3) acceptable viewing angle, and 4) fairly good cell gap tolerance. Moreover, the electro‐optical properties in T and R regions match very well, so that single gamma curve driving is enabled. This TR‐LCD is easy to fabricate and suitable for mobile displays.

Fast-Response Single Cell Gap Transflective Liquid Crystal Displays

A single cell gap transflective liquid crystal display (TR-LCD) using dual fringing field switching mode is proposed, in which a positive dielectric anisotropy liquid crystal is vertically aligned and driven by fringing fields from both substrates. By optimizing the electrode width and gap of the transmissive and reflective regions, this TR-LCD exhibits a fast response time, high optical efficiency, single gamma curve, and wide viewing angle. Fast response time enables color sequential operation using red, green, and blue light-emitting diodes without noticeable color breakup. Potential application of this TR-LCD for sunlight readable mobile displays is emphasized.

Single cell gap and wide-view transflective liquid crystal display using fringe field switching and embedded wire grid polarizer

A single cell gap and wide-view transflective liquid crystal display (TR-LCD) using fringe field switching and embedded wire grid polarizer as polarization dependent reflector is developed. Such a device structure does not require any quarter-wave plate or in-cell phase retarder. Through optimizing the pixel electrode width and gap, high transmittance and reflectance and a single gamma curve are obtained. Potential application of this TR-LCD for mobile displays is emphasized.

Optimal pixel design for low driving, single gamma curve and single cell‐gap transflective fringe‐field switching liquid crystal display

When a dielectric layer, in‐cell retarder (ICR) is formed between the electrode and LC layer to obtain a single‐gap transflective fringe‐field switching (FFS) display, the driving voltage is highly increased due to the thickness of the dielectric material. In particular, the driving voltage of the transmissive part becomes very high, and goes beyond the driver integrated circuit (IC) range for mobile application because the homogenously aligned liquid crystal director should rotate twice as far as that in the reflective part. The correlation between the driving voltage and electrode structures was investigated. It was found that the problem could be solved by optimisation of the common electrode structure such that the electrode structure changed from a plane to slit shape (in‐plane field is mainly used instead of fringe field), realising a high performance FFS transflective display.

A single-gap transflective fringe field switching display using a liquid crystal with positive dielectric anisotropy

There is considerable difficulty in fabricating a reflector with embossing in an array substrate using a conventional single gap transflective fringe-field switching nematic liquid-crystal display. In order to solve this problem, we propose a new structure, which consists of a reflector on a colour filter substrate. The newly proposed structure with a complex field direction has problems such that the voltage-dependent transmittance and reflectance curves do not match each other, which necessitate a dual driving circuit. This paper reports the optimized electrode structure and calculated electro-optical results realizing a single gamma curve and high light efficiency.

Transflective In-Plane Switching Liquid Crystal Display

A single cell gap, single gamma curve, and low operating voltage transflective liquid crystal display (LCD) using an in-plane switching (IPS) cell is proposed. In the IPS cell, the pixilated transparent indium tin oxide electrodes are on the top substrate and the reflectors are on the bottom substrate. The electro-optic properties of the transflective IPS LCD are calculated using three-dimensional simulation software. By optimizing the reflector width, the voltage-dependent transmittance and reflectance curves can be matched

P-157: A Single Cell-Gap Transflective VA LCD using Positive Liquid Crystal Materials

We propose a single cell gap vertical-alignment transflective LCD with patterned electrodes using a positive dielectric anisotropic liquid crystal. As compared to prior attempts using a positive LC in VA configurations, our new design significantly reduces the threshold and on-state voltages to a range reachable by portable electronic displays. In addition, the light efficiency is also enhanced and it only requires a single gamma curve for both transmissive and reflective modes.

Transflective Liquid Crystal Display with Single Cell Gap and Single Gamma Curve

The vertical electric field-driven transflective nematic liquid crystal display with dual orientation has a problem that the voltage-dependent transmittance and reflectance curves do not match each other. Thus a dual driving circuit is required. This study shows that optimization of the surface pretilt angle in the transmittance solves this problem so that the transflective display with a single cell gap and single gamma curve for reflective and transmissive region is possible.

수직전기장을 이용한 수평배향 단일갭 반투과형 액정 디스플레이

We have designed a novel single cell gap transflective display associated with dual orientation of the liquid crystal. Owing to hybrid alignment in reflective part, the effective cell retardation value becomes half of cell retardation value in transmissive part where the LCs are homogeneously aligned. This study shows the possibility to manufacture the transflective display with a single gamma curve for reflective and transmissive region. The new device shows a high image quality with relatively easy fabrication.

P-115: Optimization of Electrode Structure for Single Gamma in a Transflective IPS LCD

In this paper we report the optimization of the electrode structure for a single gamma curve in a single-cellgap transflective IPS LCD. We optimized the distances between electrodes and the angles between LC directors and electrodes to achieve a single gamma curve.