Kazuhiro Wako

High-performance OCB-mode field-sequential-color LCD

— Optically compensated bend (OCB) mode is a promising technology for future high-quality display devices due to its wide viewing angle without gray-scale inversion and color shift, fast response time, high contrast ratio, and wide temperature range. This paper summarizes the developments of the OCB mode and the optical performance of OCB-mode field-sequential-color LCD.

P-179L: Late-News Poster: Analysis of Temperature Dependency on the Viscosity Coefficients and Flow-effect of Liquid Crystal, and their Influence on Response Time of OCB, ECB and VA Modes

According to a popularization of LCD-TVs, realization of high-performance moving image LCD, such as field sequential color LCD, is required. This paper points out that we have clarified the temperature dependency of viscosity coefficients and flow effects that are great relevance to response of LC comparing among OCB, ECB and VA modes. From mentioned results, we have designed and realized the high-speed response prototyped OCB-mode field sequential color TFT-LCD of 15-inch XGA in consideration of temperature dependency.

Improvement of Transmittance and Viewing Angle of Optically Compensated Bend Mode Liquid Crystal Display Using Wide-Viewing-Angle Circular Polarizer

A field sequential color liquid crystal display (LCD) has been developed using an optically compensated bend (OCB) mode liquid crystal cell and a light-emitting diode backlight. Application of a wide-viewing-angle- and wide-band-type circular polarizer realized a wide-viewing-angle and high-transmittance OCB-mode LC cell. In this paper, we describe the principle of the optical compensation and the fundamental characteristics of an advanced OCB-mode LCD.

LP‐4: Late‐News Poster: Overdrive for Compensating Color‐Shift on Field Sequential Color TFT‐LCDs

This paper points out that field sequential color method causes color-shift artifact on TFT-LCDs in its nature, and that overdrive scheme can work for the purpose of eliminating the artifact. It also reports the effect of overdrive measured on our prototyped OCB-mode field sequential color TFT-LCD of 6-inch VGA-size.

17.1: Invited Paper: High Performance OCB-mode for Field Sequential Color LCDs

Optically compensated bend (OCB) mode is a promising technology for future high quality display devices due to its wide viewing angle without gray scale inversion and color shift, fast response speed, high contrast ratio and wide temperature range. This paper summarizes the developments of the OCB mode and the optical performance of OCB mode field sequential color LCD.

Relation Among Micro-Structure of Rubbing Fiber, Shape of the Microgroove of Rubbed Polymer and its Anchoring Strength

Abstract To clarify the surface alignment mechanism of liquid crystal in detail, we have tried a simplified rubbing by using only one fiber, which we call “one-fiber-rubbing”, and observed the microgroove. Then, we compared the curvature of microgroove structure observed by atomic force microscope (AFM) and friction force microscope (FFM) with that of the fiber observed by scanning erectron microscope (SEM). From the result, we confirmed that they agreed well with each other. Therefore, we concluded that the microgroove is formed by micro-structure of the fiber edge. We also measured anchoring strength of the rubbed polymer surfaces with various pitch of the microgroove. From the result, we found that the anchoring strength is almost proprotional to the ratio of the total area of each microgroove in unit area.

A fast-switching OCB-mode LCD for high-quality display applications

— Optically compensated bend (OCB) mode is a promising technology, due to its wide range of viewing angles without gray-scale inversion or color shift, fast response, high contrast ratio, and wide temperature range. This paper summarizes the fundamental characteristics of OCB mode and discusses the development of field-sequential-color displays and 3-D displays for future high-quality display applications.

P‐229L: Late‐News Poster: Development of Super High Performance OCB Mode for High Quality Color‐field Sequential LCDs

A color-field sequential LCD using a high contrast OCB mode liquid crystal and a LED back-light has been developed. We established an evaluation method for a polymerized discotic material compensation film and an optimization method for a bend alignment LC cell. The prototype of OCB mode LCD has a high contrast ratio of 1350:1 and wide viewing angle over 170deg. In this paper, the concept of optical compensation and fundamental characteristic of advanced color-field sequential OCB mode LCD is discussed.

Chiral Additive Effects on Bend Growth Rate for an Optically Compensated Bend-Mode Liquid Crystal Display

We investigated bend growth processes for an optically compensated bend (OCB)-mode liquid crystal display. The bend growth consists of two transformations. i.e., the transformation from symmetric splay alignment to bend alignment and that from asymmetric splay alignment to bend alignment. We observed the temperature dependence of bend growth processes and detected the asymmetric splay-to-bend transformation at 0 °C. We investigated the kinetic effects of a chiral additive on the bend growth processes in three directions, i.e., the same as, and opposite and perpendicular to the rubbing direction. The chiral additive did not affect the symmetric splay-to-bend transformation, however, it was found to accelerate the asymmetric splay-to-bend transformation in all three directions. This acceleration is attributed to the chirality-induced coexistence of top and bottom splay alignments in the asymmetric splay regions.

Development of high definition liquid crystal display with excellent moving image

It is easy for the liquid crystal to save the electric power for non-emissive display essentially in various flat panel displays, and to improve the electro-optical property by function separation of a light source and an optical control, etc. However, the utilizing efficiency of light in liquid crystal displays is about several %. One of the low efficiency factors is a color filter. We adopted the FS method to switch the light source color using OCB mode with excellent switching speed. This method is a technology that displays full colors by switching a red, green, blue image at high speed sequentially. The merit of this method is high efficiency without using the color filter that absorbs 67.1% of the backlight, and it is a useful skill to the power consumption reduction of the liquid crystal panel. In addition, there is an advantage that clear motion image can be displayed for this method to blink the source of the backlight at high speed. The 6-inch LCD panel with the FS OCB mode was manufactured. The clear motion image, high utilizing efficiency of light, and large color gamut were achieved.