Shoichi Matsumoto

Field‐induced deformation of hybrid‐aligned nematic liquid crystals: New multicolor liquid crystal display

Electric field‐induced deformation is studied in a unique hybrid‐aligned nematic (HAN) cell, in which the director of a nematic liquid crystal (LC) with either positive or negative dielectric anisotropy is varied continuously, lying perpendicular to one substrate and parallel to the other. The experimental results show the absence of threshold field in the birefringence–vs–applied voltage relationship as well as the slow variation of birefringence with voltage; these phenomena are analyzed in terms of the Frank‐Oseen continuum theory. Also, the above characteristics of HAN are demonstrated to have such advantages in multicolor LC display applications as low operating voltage and fairly good color separation together with uniform and bright color generation.

Invited Lecture. Matrix liquid-crystal display device technologies

Abstract Our recent studies of ferroelectric chiral smectic and super-twisted nematic (ST) multiplexed-matrix liquid-crystal displays (LCDs) and a thin-film-transistor (TFT) active-matrix twisted nematic (TN) LCD are presented, mainly in terms of liquid-crystal material and cell optimization. This is based on a consideration of their electro-optical characteristics. In addition the matrix LCD devices developed through these studies are introduced, including a 12-inch-diagonal video-rate multicolour ferroelectric LCD, a highly multiplexed genuine achromatic ST LCD with a single cell and a 4-inch-diagonal full-colour a-Si TFT-addressed TN LCD for a video display.

Surface‐induced molecular orientation of liquid crystals by carboxylatochromium complexes

Tetrachloro–μ‐hydroxo–μ‐carboxylatodichromium (III) complexes have been used to induce homeotropic alignment of nematic, smectic, and large‐pitch cholesteric liquid crystals. A dynamic scattering degradation test has shown that this orientation is remarkably stable.

Ir-coated dispenser cathode for CRT

A compact dispenser cathode has been developed for application to cathode ray tubes (CRTs). A cathode emitter, comprising BaO, CaO, and Al/sub 2/O/sub 3/ in a molar ratio of 4:1:1, was impregnated into a porous tungsten pellet. An intermetallic compound of tungsten and iridium was formed on the cathode pellet. Heater ratings were 6.3 V*0.2 A. Emission characteristics were measured by using color CRTs. As a result, a cathode peak loading of 15 A/cm/sup 2/ was ensured in the space-charge region. Furthermore, life tests with a peak loading of 7.5 A/cm/sup 2/ were conducted over 10000 h. The decrease in emission current after 10000 h was within only 10% of the initial value. Reliability of cathode performance was assured in terms of breakdown potential between the heater and the cathode, emission characteristics, life performance, grid emission, and the drift in cutoff potential. In addition, the effects of the coating thickness on the emission characteristics are discussed. >

Multiplexed ferroelectric liquid crystal display

Abstract The studies on the fundamental requirements for realization of a multiplexed ferroelectric liquid crystal (FLC) display have been presented as follows: (1) The new classes of 2,5-diphenylpyrimidine FLCs are useful as a blending component for broadening the Sc temperature range and improving the switching response time. (2) A FLC material with the Iso-N-SA-Sc phase transition sequence as well as the long Sc and N helical pitches is required to achieve the homogeneous alignment in a Sc phase. (3) Among the FLC cells with various alignment layers, the PI/PI coated cell exhibits the symmetric and steep bistability threshold behavior. (4) The parameters to evaluate the multiplexing capability of a FLC cell are introduced and applied to select a suitable combination of alignment layers for highly multiplexing. (5) The parameters are also used to evaluate a favorable drive method among the drive schemes proposed so far for multiplexing a FLC cell. On the basis of the above studies, a multicolor ferroele...

Anthraquinone-Based Dichroic Dyes for Achromatic Black Guest-host Liquid Crystal Display

Abstract The properties of three different classes of 2,3-substituted 1,4-diaminoanthraquinone dichroic greenish blue dyes with a maximum absorption peak in the long wavelength region from 660 nm up to 760 nm, which are useful as a guest dye in an achromatic black guest-host liquid crystal display, have been investigated. 1,4-Diaminoanthraquinone-(N-substituted-3-imino)-2,3-dicarboximidines (I) and 1,4-diaminoanthraquinone-(N-substituted-3-thioxo)-2,3-dicarboximidines (II) exhibit higher dichroic ratios and higher solubilities and moreover the latter class (II) shows a maximum absorption peak at a much longer wavelength, compared to 1,4-diaminoanthraquinone-(N-substituted)-2,3-dicarboximides (III). The order of various properties in the three classes of dyes are as follows: II > I > III for dichroic ratio, II > I > III for solubility, and II > III > I for maximum absorption wavelength, respectively.

Surface‐produced parallel alignment of nematic liquid crystals by polynuclear dicarboxylatochromium complexes

Dicarboxylatochromium complexes have produced very stable parallel molecular alignment of nematic liquid crystals, in contrast with a recently described perpendicular orientation by monocarboxylatochromium complexes. The complexes used are μ‐dicarboxylato‐bis (tetranitro‐μ‐hydroxodichromium (III))’s which bond chemically to substrate surfaces.

A single-cell high-quality black and white ST LCD

A genuine achromatic supertwist liquid-crystal display (ST LCD) characterized by a single-cell construction has been developed by inserting an optical retardation film between the liquid crystal cell and polarizer. The device realizes not only a high contrast ratio and a good viewing angle, comparable to that of a double-cell ST LCD, but also light weight, thin design, and low cost due to the single cell construction. The electrooptical characteristics and display performance of the LCD are described.<<ETX>>

A single-cell high-quality black and white ST liquid-crystal display

A truly achromatic ST liquid-crystal display (LCD) characterized by single-cell construction has been developed by inserting an optical retardation film between the liquid-crystal cell and the polarizer. It provides not only a high contrast ratio and a good viewing angle, comparable to a double-cell ST LCD, but also such excellent features as light weight, thin design, and low cost due to the single-cell construction. >

Large-area Projection HAN-mode Multicolor TFT-addressed LCD

Abstract A liquid crystal multicolor projection display using a TFT-addressed hybrid-aligned nematic (HAN) cell without a color filter has been developed. Compared to a TFT color LCD with an RGB color filter, it has such advantages as five times brighter display and three times higher resolution.