Reflective LC Cell Research Articles

반사형 쌍안정 카이랄 스플레이 네마틱 액정표시소자

Bistable chiral splay nematic liquid crystal display (BCSN LCD) is a memory type liquid crystal display using splay and twist states as two stable states. When the cell thickness to pitch (d/p) ratio is 0.25, splay and twist states have permanent memory time. However, when the transition from twist state to splay state is caused by a fringe field, pixel regions show that the splay state is not perfect, but rather includes a contribution from the twist state. In this paper, we propose a reflective BCSN LCD using twist state in which the two stable states do not coexist. The fabricated reflective BCSN LC cell shows a high contrast ratio of over 30:1 and response times of 950 ms and 450 ms in vertical and fringe field switching, respectively. The proposed cell also shows wide viewing angle characteristics of in left- and right directions.

내장형 위상자를 이용한 반사형 45˚ 비틀린 네마틱 액정 디스플레이의 전기광학 특성에 관한 연구

We have studied electro-optic characteristics of reflective <TEX>$45^{\circ}$</TEX> twisted nematic liquid crystal display which implement the new LC orientation using of in-cell retarder film. For the embodiment of reflective liquid crystal display, essentially the optic compensation films was always needed and attached to the outside of glass substrate. In our study, these optic compensation film were not employed in reflective LC cell. On other hand we have employed the in-cell retarder to substitute the optic compensation film and were able to orient the LC molecules using this in-cell retarder. So we have developed the reflective LC cell that has good optical performances without any additional coating process on the in-cell retarder.

37.4: Production Line Characterization of LC Cells

We present the system MePaLC for characterization of empty and filled transmissive and reflective LC cells in a production line. Cell gap and twist angle are determined from spectroscopic measurements in real time. The measurements do not require knowledge of an alignment direction.

13.4: Cell Gap Measurements of Flexible Reflective TN‐ and STN‐ LC Cells

AbstractWe propose several new methods for measuring cell gap of filled reflective LC cells on plastic substrates. Cases when plastic is anisotropic, and the LC cell consists of either one or two internal polarizers are considered. Proposed methods are well suited for both reflective and transmissive LC cells.

Eigenmodes of a reflective twisted-nematic liquid-crystal cell

The eigenmodes of a reflective twisted-nematic liquid-crystal (TN LC) cell are analyzed based on the Jones matrix method. Two models are developed to describe the LC system in the low- and high-voltage regimes. The simulated transmission spectra of LC Fabry–Perot etalons are used to investigate the eigenmodes. In a general reflective TN LC cell, the eigenmodes are two orthogonal linear polarization states. Under some specific conditions, these two linear polarization states will approach the bisector or orthogonal to the bisector of the TN LC cell. This bisector effect is useful for reducing the operating voltage and enhancing the contrast ratio of LC display devices and for eliminating the mode coupling of the tunable Fabry–Perot etalons.

Low-Cell-Gap Measurement by Rotation of a Wave Retarder

A simple method of measuring the cell gap of a low-cell-gap twisted nematic liquid crystal (TNLC) cell is proposed. Unlike the conventional methods which make use of a rotatable polarizer and analyzer or a compensator set between a pair of crossed polarizers, the proposed method uses a wave plate set on top of a motor by which we rotate the plate by 360°. With the proposed method, we can measure the cell gap of TNLC cells with a low cell gap below 4 µm. The proposed method can also be applied to single-polarizer reflective LC cells.

26.2: A Two‐Dimensional and Hyperfine Measurement Method of Cell Parameter Distributions in the Reflective LC Cell by Using a Stokes Parameter Method

AbstractWe propose a two‐dimensional (2D) measurement method for precisely determining cell parameter distributions in reflective LC displays. The hyperfine 2D cell thickness distribution can easily and rapidly be determined by measuring Stokes parameters of the LC cells for each pixel of a CCD camera.

P‐31: Cell Gap Measurement Methods for Low‐Cell‐Gap and Single‐Polarizer Reflective LCDs

AbstractWe propose two novel methods to measure the cell gap of a liquid crystal cell. One is a method to measure the cell gap of a low cell‐gap TNLC cell by rotating a quarter‐wave retarder. With the proposed method, we can measure the cell gap d of TNLC cells with d &lt; 4 μm. The other is a method to measure the cell gap of a single‐polarizer reflective LC cell as well as the wavelength dependence of the retardation Δnd by using a spectrometer.

Twist- and Supertwist Antidazzling Devices With Local Reduction of Brightness

Abstract Single- and multichannel optoelectronic modulators with twist- and supertwist transmissive or reflective LC cells are described. The possibility of antidazzling aplications of these devices at low background intensity (0, 1–10 1x) is discussed.