Shinichi Komura

57.1: Novel Pixel Design for a Transflective IPS-LCD with an In-Cell Retarder

We have successfully developed 2.4″QVGA transflective IPS-LCDs which maintains excellent transmissive performance and higher reflectance. We have an in-cell retarder patterned only in the reflective region. And we devised the pixel design so that the reflectance became higher. We have realized transflective LCDs with sufficient outdoor readability and wide viewing angle. Furthermore, we reduced thickness of the LCD panel at the same time.

P-231L: Late-News Poster: A Wide Viewing Angle Transflective IPS LCD Applying New Optical Design

Viewing angle performance of transflective LCDs, affected by many optical parameters such as Nz of retardation films and azimuth of slow axis, is improved when the optical parameters obey a simple rule. A new optical design is deduced from the rule, and applied for transflective IPS-LCD with a single gap structure and a twisted liquid crystal layer. A viewing angle performance comparable to transmissive IPS LCDs is realized in transflective IPS-LCD.

46.3: A 2.2″ QVGA a-Si TFT LCD with High Reliability Integrated Gate Driver

A 2.2″ QVGA a-Si TFT-LCD with a novel integrated gate driver has been developed. High reliability is achieved by assigning pull-down and retention processes to two individual TFTs and by stabilizing the gate voltages of the pull-up TFTs. The developed LCD shows sufficient performance even at −35°C after a 5000hour operation test at 55°C.

57.4L: Late-News Paper: Transflective LCD Combining Transmissive IPS and Reflective In-Cell Retarder ECB

In-cell retarder technology enables two kinds of display modes with different features to be realized in the pixels of transflective LCDs. Using this concept, we have developed a prototype 2.2″ QVGA transflective LCD that combines transmissive IPS for wide viewing angle performance and reflective in-cell retarder ECB for high reflectance.

Optimization for black and white representation in reflective STN‐LCDs with single polarizers

— An optimization method is proposed for achieving black and white representation in reflective STN-LCDs with single polarizers which consist of an STN cell, a polarizer, and a reflector with two birefringent films between the STN cell and the reflector. In this method, the two films are optimized to achieve good black representation while an optimum voltage is applied to the STN cell. Good black and white representation with a maximum contrast ratio of 5:1, reflectance of 22%, and good achromaticity are achieved for an STN-LCD fabricated using this method.

Enhancement of Viewing Performance of New Transflective In-Plane Switching Liquid Crystal Displays Using In-Cell Retarder(s)

High-viewing-performance transflective in-plane switching (IPS) liquid crystal displays (LCDs) with in-cell retarders have been developed. Transflective LCDs have pixels with transmissive and reflective display portions; the transmissive display portion is designed to have the same structure as the transmissive IPS-LCDs, and the reflective display portion is formed by patterning the in-cell retarder. The latter is designed to give a normally close mode characteristic, which has a brightness–voltage (B–V) curve similar to that of the former. The reflective display portions, which work as quarter-wave plates at dark states, can be classified into five structures according to the number of in-cell retarder(s) and the stacking order of the liquid crystal layer. In this study, on the basis of the five possible structures, the viewing performances of the transflective IPS-LCDs are investigated by simulation, and suitable solutions are also discussed.

Fabrication of vertical alignment in ferroelectric liquid crystals for display application

In this study, we focus on vertical alignment ferroelectric liquid crystals (VA-FLCs), because an FLC display with a high contrast ratio is expected. In the VA, although the normal of smectic layers is vertical to the substrate surface, the director of FLC molecules must tilt to the substrate surface at the tilt angle of FLC molecules. Thus, it is usually difficult to obtain a uniform VA in FLCs. We determine the optimum conditions for the fabrication of VA-FLC cells in terms of the tilt angle of FLC molecules, the anchoring strength of the alignment film, and the cell gap. Results indicate that the FLC with a small tilt angle tends to form good VA, which can be obtained by utilizing alignment films with high surface anchoring strengths. Good VA strongly depends on the cell gap.

Influence of Fabrication Conditions on Monostability of Polymer-Stabilized Ferroelectric Liquid Crystals

Polymer-stabilized ferroelectric liquid crystals (PS-FLCs) photocured in the SmA phase can show monostable V-shaped electrooptical characteristics. In this study, we have researched the influence of the fabrication conditions such as polymer concentration, cell gap, and alignment film materials on the monostable electrooptical characteristics of PS-FLCs. As a result, it is confirmed that the monostable capability strongly depends on the polymer concentration. However, the driving voltage increases as the polymer concentration increases. Therefore, to fabricate practicable PS-FLC devices, it is important to investigate the effects of other factors on the monostable capability. From the investigation of the influence of the cell gap and the alignment film materials on the monostable capability of PS-FLCs, it is concluded that the surface anchoring of the alignment film strongly influences the monostable characteristics of PS-FLCs photocured in the SmA phase.

A Monochromatic Black and White Supertwisted Nematic Liquid Crystal Display with a Single Cell and a Birefringent Film

To achieve a monochromatic black-and-white (B/W) STN-LCD with a single cell and a birefringent plastic film, the optimum conditions of optical properties in the birefringent film are analyzed theoretically and experimentally. By optimizing the film retardation to minimize the transmission of a STN-LCD at 550 nm, optical retardation in a STN cell is canceled and a B/W STN-LCD is obtained. By selecting the suitable conditions for compensating retardation of the STN cell, a B/W STN-LCD is achieved with the contrast ratio of 10:1.

P‐192L: Late‐News Poster: Moiré Reduction of Luminance Enhanced LCDs with a Wobbled Micro‐Lenticular Lens

We developed a novel lenticular lens, whose edge lines were modulated with a sinusoidal form, for a luminance enhanced LCD to reduce moire fringe between lenses and prism sheets and demonstrated the moire reduction to 1/5 with the wobbled lenticular lens formed by a printing method.