Since the liquid-crystal material was discovered, one century has already passed, and a quarter of a century or so has gone by since it was put into first practical use for "Displays". In recent years, liquid-crystal displays (LCDs) are widely used in various information appliances, and they play an important role as an "Information Window" of digital network. However, the big paradigm shift is now arising in such LCD field because of drastic evolution in both digital network infrastructure and communication technologies.

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Uike in antiferroelectric liquid crystals, unpredictable liquid crystal structures would be formed by unconventional intermoiecular interaction. One of the most important examples is bent-core mesogens, in which chirality and polarity emerge despite being achiral molecules. This mesogenic system is the first topic of this talk. Intermolecular chiral recognision also provides molecular association, that forms some new phases, i.e., cubic phase and smectic analogue of the blue phase. These two topics will be presented.

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Liquid crystallinity of the semi-rigid polymers is affected by the flexible chain length, linkage fashion between rigid and flexible chains, and rigid cores, etc. The twin type of model compounds play more important role to demonstrate the thermal properties of the semi-rigid liquid crystalline polymers than the core type of model compounds. We study liquid crystallinity of twin type compounds containing cyanostilbene as mesogen by polarized optical microscopy, differential scanning calorimetry, and X-ray diffraction measurements. Thermal properties of these model compounds changed with flexible chain length, linkage fashion between rigid and flexible chains, and the position of cyano groups in the central group of mesogen.

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New liquid crystalline compounds containing phosphorus were synthesized. Phosphorus derivatives having terminal group with an alkoxy moiety or an ethylene oxide mojety in terminal show schlieren texture. The phosphorus derivative possessing an asymmetric carbon atom in terminal group shows oily streak texture. By X-ray diffraction measurement of the compounds possessing an alkoxy moiety or an ethylene oxide moiety, one sharp peak and one broad peak were detected at the mesomorphic temperature in the small angle and wide angle regions, respectively. Therefore, mesophase of the compounds possessing alkoxy moiety or ethylene oxide moiety were assigned to a smectic C phase, while the compound possessing an asymmetric carbon atom in terminal was attributed to a cholesteric phase.

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Thermal behaviors of α-disubstituted oligothiophenes having thiophene rings as the rigid core were investigated. The influence of the substituent at the α-position on the thermal behavior is discussed. 5,5"-dicyanoterthiophene exhibited a nematic liquid crystalline phase at 205℃ on cooling. It should be emphasized that this molecule Jacks in a flexible substituent such as a long alkyl chain.

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Some derivatives of 4-(4-Alkoxyphenoxycarbonyl) phenyl 4-alkoxy-3-nitrobenzoates and 3-alkoxy-4-nitrobenzoates were synthesized, and thermotropic behavior and the layer sturcture of the smectic A and C phases were examined. The layer structure is discussed in terms of the molecular structure calculated by semi-empirical molecular orbital method.

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In order to make clear the origin of chiral interactions responsible for an isotropic mesophase (IsoX) of a dichiral mesogen, 2-[4-[(R)-2-fiuorohexyloxy]phenyl]-5-[4-[(S)-2-fluoro-2-methyldecanoy- Ioxy]phenyl]pyrimidine (I), crystal structures have been determined for I and its isomers (II and III) without IsoX. According to the different positions of N atoms in the cores, crystal structures are quite different each other: one-dimensional chains of CH^<…>N close contacts resulting in the large overlapping of core moieties and hence, stereo-specific F-methyl interactions (I), an MHPOBC-like arrangement of bent molecules (II), and a stack of layers composed of parallel molecules (Ill).

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We reported that a rod-like dichiral liquid crystal 2-[4-[(R)-fiuorohexyloxylphenyll-5- [4-[(S)-2-fluoro-2- methyldecanoyloxy[phenyl]pyrimidine upon cooling exhibits an cndothermic transition from a chiral smectic C phase to an optically isotropic phase (IsoX). Recently the crystal structure of the compound has been determined. We will discuss intermolecular interactions responsible for the appearance of the IsoX phase.

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Zigzag defects in ferroelectric liquid crystal displays (FLCDs) originate from the structural transformation from C1 to C2 chevrons during the cooling process. This transformation occurs so as to accommodate the increasing tilt angle of the FLC under the constraint of the surface anchoring. Based on this scenario of defect formation, we propose a new scheme to obtain zigzag defect-free FLCDs in which the C1-C2 transformation is suppressed by the use of an interfacial layer that has a gradually decreasing SmA-SmC^* transition temperature toward the substrate.

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Ferroelectric liquid crystal materials without having SA phase in their phase sequence show Half-V switching. We have adopted photoalignment to fabricate H-V-FLCD using this kind of FLC material and the results were compared with those by using rubbing technique. It is shown that EO characteristics of H-V-FLCD is strongly dependent on the surface anchoring, and actually photoalignment produces low voltage operation and large deflection apparent tilt angle of FLC molecules.

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We have investigated the function and ability of ion trapping films deposited on ITO films in a monostable FLCD exhibiting V-shaped switching that is fabricated by mesogenic polymer-stabilization, through which some ions are introduces in a cell. We report the effect of the removal of some ions through the measurements of switchability with FETs, voltage holding ratio, and switching current that depend on the degree of photocure.

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A field sequential fullcolor (FS-FC) LCD has been successfully fabricated taking advantages of half-V switching nature of FLCD adopted in this research and its' fast response, and further by using developed RGB LEDs as a modulated backlight. Special FLC materials, which have no SmA phase, exhibit half-V switching. These devices are called H-V-FLCDs. We measured the performance of the FS-FC-LCD and it is shown that the display exhibits high luminance, wide color gamut, and also blurring free nature of moving bars. This performance may be brought about by the fast response of our H-V- FLCD and the same time, by the impulsive nature of FS-FC-LCD system.

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We have fabricated FET driven Field Sequential Fullcolor LCDs using polymer stabilized FLCDs showing V-FLCD or H-V-FLCD. H-V-FLCD has no SA phase. On our FS-FC-LCD moving 8 color bars are displayed with the frame rate of 60Hz to 300Hz. The fabricated FS-FC-LCD is featured by high luminance and wide color gamut. Displayed patterns are taken with a CCD digital video camera whose shutter speed is variable (less than 1/60 sec). We evaluated the blurring properties of a moving color bar. It is shown that a moving bar displayed on the FS-FC-LCD is blurring free even its' speed is 15cm/s, contrary to this conventional a moving bar on a TN-LCD generate a heavy blurring tail when moving speed is 14.5cm/so.

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Numerical simulations of smeclic C liquid crystalline flow between parallel plates have been performed using the continuum theory for sinectic C liquid crysials proposed by Leslie et al. The flow of the smectic liquid crystalline materials are described in terms of the unit vector n parallel to the local averaged molecular orientation, the unit vector a normal to the smectic layer, and the veiocity vector. Velocity and molecular orientation fields are computed for smectic layer configurations between parallel plates.

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In the B7 phase of the racemate of MHOBOW, a lot of textures are observed. In this paper, the various types of local layer structures in the B7 phase were investigated using X-ray microbeam. In the gold-yellow-colored circular domains of 4-5 μm-thick cells, the layer apart from the circle center forms monotilted structure with ω〜15°, and ω decreases and the observed rocking curves were very broad as the irradiated position approaches to the center. In so-called banana-leaf domains, severaf periodic sharp peaks were observed, suggsting that the layer was kinked several times along the substrate normal. Furthermore, it was found that the diffraction peaks corresponding to lhe different layer spacings as observed in the powder X-ray diffraction was detected at the different chevron angle peak positions of the same irradiated position.

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Recently a new type of ferroelectricity was found in a fluid smecric phase of a new type of bent-shaped molecule, called P-8-O-PIMB6, which is a P-8-O-PIMB analogue bui has chiral carbons in both end chains. Since the polar ordcr is eguivalent to a nonsymmctric molecular arrangement. the ferroelectric system can be highly active for second-order nonlinear optics. So the second-order nonlinear phenomenon (ex. SHG: Second Harmonic Generation) becomes a powerful tool to irrvestigate these polar properties. In this study. we measured transmitted SHG from well-aligned domains in the ferroelectric phase of the P-8-O-PIlMB6 to look into the layer structure.

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The helical structure of the B_4 phase in the banana-shaped molecules, the 1,3-benzene bis[4-(4-n-alkoxyphenyliminomethyl)benzoate] (P-n-O-PIMB) series, has been studied by means of optical microscopy, X-ray diffraction and circular dichroism for homogeneously and homeotropically aligned cells, showed a transparent blue color and a circular dichroism at about 400nm, indicating the existence of a helical structure, Detailed texture observation also reveals the existence of two helical domains with opposite helical senses. The two helical domains are formed with equal probability, and with the helical axes parallel to the layers similar to the twist grain boundary (TGB) phase. This helical structure is also supported by X-ray diffraction. The balance between the two domain arcas is broken by doping P-n-O-PIMB with its chiral analogue. The texture of the homeotropically aligned cells suggests two different helical axes, both of which are parallel to the layer but with one parallel and the other perpendicular to the bent-core plane.

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Spontaneous optical resolution of a racemic diastereomer, (R,S)-β-Me-TFMHPOBC in a smectic phase were studied by molecular dynamics (MD) simulations. We found the molecular conformation symmetries of the two enantiomer were largely different each other depending on their chiralities. Special attention was paid on the relationship between this conformational asymmetry and spontaneous optical resolution in this racemic system.

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Helical structures formed by smectic-A lilaments in an isotropic phase have been observed in the binary mixture of octyloxycyanobiphenyl and dodeeyl alcohol using a polarizing microscope. In 1984, helical ribbons of chiral lipid bilayers have been reported while smectic-A helical filaments observed here are tubular filaments. The existence of Smectic-A helical lilaments have also been theoretically investigated. The shape equation for smectic-A filaments has been derived by a variation of the sum of Gibbs free energy, curvature elastic energy and surface energy of the filaments. It is found that the smectic-A helical filaments are a solution to the shape equation.

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Panarin et al. reported that the phase so far identified as SmA in one component compound of the Inui mixare must be a random polar SmC-like phase, SmC_R. We have studied the same material by using polarized Raman scattering to decide whether it is a SmC_R phase or an ordinary SmA phase. By comparining the experimentally obtained apparent orientationl, order parameters, <P_1> and <P_4>, with the simulated ones, we have concluded that their identification is probably wrong. It must be the ordinary SmA phase but not the random polar SmC-like phase.

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Correlation field approximation theory in the transfer matrix method is developed to analyze the correlation functions at an anisotropic system. In the ferro- and antiferro-electric smectic structures, the correlation functions in both directions of layer normal and within the layer are calculated at various temperatures, and weak interlayer correlation is depicted, where the long range order is isotropic in nature.

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The heat capacity has been measnred near the smectic-A smectic-C_A-smectic-J_A phase transitions in a racemate antiferroelectric liquid crystal MHPOCBC. A high presicion ac calorimeter has been used for the measurement. The transitions were found to be weakly first order. The heat anomalies have been analyzed using a power-law equation.

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A great deal of effort has been made on theoretical studies of electric field induced change of helical structure in smectic liquid crystal. It has been believed that the helical structure in SmC^* is unwound at low field. We succeed in analyze the process to helix unwinding by electric field in SmC^* and found that the complete unwinding occurs at relatively high field than one believed. We will also discuss the molecular orientation in distorted helical structure by electric field.

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Local layer response of ferroelectric and antiferroelectric liquid crystals (FLC and AFLC, respectively) was measured using a synchrotron time resolved microbeam X-ray diffraction simultaneously with an optical response. The layer deformation process in AFLC under a triangular electric field had a double hysteresis similar to the transmittance. On the other hand, in FLC, the local layer modulated while the optical response was kept constant Detail of the transient local layer response of FLC was clarified by the time resotved microbeam X-ray diffraction to a step form electric field. The horizontal chevron structure at high field was relaxed within 0.1ms to the quasi-bookshelf structure at 0V. This process is similar to the deformation of the ferroelectric state of AFLC.

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Recently, we have been shown that nano hybrid films composed of polymers functionalized with azobenzene and liquid crystals show photoinduced mass-migration to form surface relief gratings (SRG) under the strikingly short exposure of an interference laser beams. In this study, influences of the components structure were investigated to gain further information about the efficient SRG formation. We also report the results of temary hybrid films containing dye molecules to visualize material transfer by optical microscopy.

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A new series of liquid crystalline (LC) homopoloymers of poly {11-[4-(4-butylphenylazo)-phenoxyl-undecy] methacrytate} and their block-copolymers with polystyrene were synthesized by using atom transfer radical polymerization (ATRP)method. Thermal propertics were investigated by using DSC, X-ray diffraction and polarized phases. Nanostructures in the range of 20〜40nm were observed by using TEM, SAXS, and AFM. Different chromophore aggregation and photo-chemical behabiors between anncaled block copolymer and homopolymer films were observed, which might be attributed to microphase separation in the block copolymer thim films.

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To date little knowledge has been obtained on the ultrathin film formation of main-chain type liquid crystalline (LC) polymers at the air-water interface. We report herein the Langmuir monolayer formation of a family of amphiphiiic main-chain LC polymers containing oligo(ethylene oxide) (EO) chain. The spreading behavior, contact angle of water, atomic force microscopy and UV-visible absorption spectroscopy all support the packing modal that the main chain is folded at every EO unit with a stretched aikylene spacer in the monolayer Clear odd-even effects stemming from the carbon number of the alkylene spacer were also found.

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A hydrophobic polymer alone does not form a spread monolayer on water, but our recent work showed that monolayer formation of a fully hydrophobic polysilane is attained when they are co-spread with a cyanobiphenyl type liquid crystal molecule (5CB). We report herein some extended results of this work using poly(alkylthiophen)s and polystyrene. Spreading behavior and AFM observations revealed the monolayer formation of these polymers, indicating the wide applicability of the liquid crystal-assisted process.

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Some derivatives of 4-(4-Alkoxyphenoxycarbonyl)phenyl 5-cyano-2-furancarboxylates were synthesized. The higher members show a smectic A phase with a bilayer arrangement. The members form a Langmuir and Langumuir-Blodgctt films. The layer structure of both states was examined by an X-ray diffraction measurement, and is discussed in terms of the molecular structure calculated by semi-empirical molecular orbital method.

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The surface excess of binary nemaIic liqulid crystal mixrures w as investigated by means of regualar solution theory, which is one of the thermodynamic lreatments for non-ideal syaems. Solubility parameters were used to estimae both the activity coefficient and the surface tension fox liquid crystals. In this study, we wish to report that the surface composition of liquid crysiai mixlures can be influenced by the molecular interaction in the bulk solution.

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The charge carrier transport property of the lamello-columnar mesophase of a [l}benzothieno[3,2-b][1]benzothiophene-2,7-dicarboxylate (BTBT) derivative was investigated by time-of-flight technique. BTBT exhibits a bipolar charge transporr, in the mesophase with comparable electron and hole mobility values in the order of 2×10^-3 cm² V^-1 s^-1. The high mobility values obtained for this disordered smectic phase can be explained by the improved π-overlap between lath-shaped aromatic moieties in the short-range columnar stackings.

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Charged carrier mobilities of the photopolymerized tfiphenylene films were evaluated by the Time-of-Fright (TOF) method. The triphenylene derivatives are known to show fast carrier mobilities (>10^-3cm²/Vs) in columnar phases. In this study, the carrier mobilities of triphenylene films photopolymerized at discotic nematic phase were measured to reveal. Those films gave the comparable carrier mobiltries with the columnar phases. The results of carier mobility measurements for the photopolymerized films prepared under several different conditions will be described.

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Strong optical phase conjugation from high-performance photorefractive mesogenic composites was observed by means of degenerate four wave mixing techniques. We extensively investigated phase conjugate reflectivities, which depended on both pump beam intensity ratio and spatial phase shift.

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The photorefractive effect of a series of low-molecular-weight ferroelectric liquid crystals (FLCs) doped with photoconductive compounds was investigated using two-beam coupling experiments. Asymmetric energy exchange was observed only in the ferroelectric phase, and the refractive index formation time was found to be 〜30 ms, which is faster than that of nematic photorefractive LCs. These results indicate that the mechanism of the photorefractive effect in FLCs is different from that in nematic LCs. The photorefractivity of a photoconductive polymer and FLC mixture was also investigated, and the effects of temperature, the strength of the applied electric field and spontaneous polarization on the diffraction efficiency were examined.

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A composite film of liquid crystal and polymer networks is useful for supporting plastic substrates of a flexible display device. In this study, we studied the molecular alignment of polymer fiber networks, which are formed in ferroelectric liquid crystal by means of photopolymerization-induced phase separation, by Raman spectral microscopy using incident polarized infrared light. From the dependence of Raman scattering on the incident polarization direction, it was found that side-chain molecular skeletons of the polymer remarkably orient in the rubbing direction of alignment layers coated on the substrates. The polymer forming process was considered due to the molecular alignment evaluation.

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In most devices for evaluating LCD parameters, the response of the measurement system to polarization impedes correct evaluation of some parameters when a polarizer is applied. Analyzing the LCT5016 measurement system, we found that results were seriously affected by the polarization-dependent sensitivity of the spectrometer and by a partially polarized light source. A series of effective methods to eliminate the influence of the light source is proposed in this paper, involving both the measurement process technique and the design of the optical system. The result has general implications for overcoming similar polarization responses when developing systems.

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In this report, we numerically analyzed the relationship between the electro-optical properties and the driving voltage in a single-polarizer reflective DTN-LCD with a retardation film in order to confirm the possibility to reduced power consumption. We found that the LCD exhibits an achromatic image of high luminous reflectance and high contrast ratio, even if the on-voltage of TFT-LCD is reduced to 2V. the power consumption can thus be decreased to about 1/6 to 1/7 of that of a conventional reflective TFT-LCD of 5V at on-state.

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A reflective color LCD of high quality, low power consumption light weight and thin structure is an important device for highly portable information terminals. In this report, we numerically analyzed the relationship between the electro-optical properties and the driving voltage in a single-polarizer reflective DTN-LCD with a quarter-wave plate. We found that the LCD exhibits an achromatic image of high luminous reflectance and high contrast ratio, even if the on-voltage of TFT-LCD is reduced to 2V the power consumption can thus be decreased to about 1/6 to 1/7 of that of a current reflective TFT-LCD of 5V at on-state.

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We have investigated a reflective-type bistable TN-LCD (R-BTN) aiming at the application to a high-performance electric paper. A theoretical study indicates that two LC alignment states with 72°- and 432°- twisted angles are one of the most suitable combination to use as a reflective-type bistable mode with high reflectance, high contrast, and a good black and white image. The experimental result confirms the theoretical considerations.

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We have developed a flexible ferroelectric liquid crystal(FLC) device containing polymer walls and networks. The polymer walls are formed to support plastic film substrates and enhance mechanical stability of the device, To prepare the flexible FLC with polymer walls, the liquid crystal and monomer solution sandwiched. between two substrates are heated to be in isotropic phase and irradiated with ultraviolet(UV) light through photomask to form polymer walls without birefringence. After that, polymer networks are formed in the area surrounded by polymer walls by irradiating the solution with spatially uniform UV light. The fabricated device between crossed polarizers exhibited gayscale display operation even when the device was bent.

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This paper describes a Mobile Fine Particle Display with liquid crystal (MFPD) with a high reflective ratio and a high contrast ratio that can rewrite when an electric field is applied and sustain displayed information without an electric field. The group of fine particles, dispersed within the nemafic LC, is controlled by the applied electric field for obtaining optical changes in MFPD cell. We are investigating displays with some kinds of electrode patterns for our MFPD cell.

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Photoreactive polymethaclates with methoxycinnamoyloxybiphenyl side group were synthesized to induce a high degree of molecular orientation. The high orientational order of the film was induced by irradiation of linearly polarized ultrabiolet(LPUV) light and subsequent annealing. Three dimensional molecular orientation in the film can be acheived by oblique irradiation with LPUV light. Optical birefringence of the film is controlled to be Δnd > 100nm. In addition, we demonstrate an optical film having reflective properly depending on lhe polarization direction of incident light.

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Liquid crystal light shutters for half-tone recording are studied. The shutters differ from traditional LC cells in that they have four termirtals. The shutters perform a stopping action with a circular or curtain-like diaphragm when signals are applied to the cell terminals. Controlling one, two or four signals varies the diaphragm.

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Fluorescent LC displays using a GH-type cell with dichroic phosphors are proposed. The fluorescence color switching property from red to blue is improved by dissolving the green and red phosphors in the LC cell. Absorption and emission properties of GH-LC cells with several mixture ratios of phosphors are measured and these color switching properties are discussed.

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We proposed a novel driving mode of nematic LCD, named 'It mode.' The main characteristics of the IT mode are of its wide viewing angle and its wide cell gap margin. We experimentally investigated the electro-optical properties of IT mode LCD, especially the viewing angle characteristics. In our presentation, we will report the influence of the electro-optic effect on the alignment film.

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We describe optical retardation film using new composite material consisting of photo-cross linkable polymer liquid crystal (PLC) and photoreactive monomer. The three dimensional alignment of the mesogenic groups was achieved by irradiation with slantwise linearly polarized ultraviolet (LPUV) light and subsequent annealing. The angle of the molecular orientation is controlled by changing the exposure angle.

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An orientated organic material has the high functionality. It is an effective method for orientating various materisls to apply the strong magnetic field. The disk-like dye molecules solution based on the water shows the property of the lyotropic liquid crystal. By applying a magnetic field to this material, oriented thin films with absorption anisotropy were made. The functionality of the film obtained with the preparation condition of the film is examined.

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A new method for characterizinh rubbing nonuniformity in liquid crystal cells is proposed. Homogeneously aligned cells made by rubbing apparently give a uniform texture under a polarizing microscope. However, nonuniformity of rubbing becomes apparent as scratched patterns, if the rubbing is preceded by rubbing or photoalignment processers. On the other hand, it was found that photoalignment gives quite a uniform texture even on a priori photoaligned surfaces. Thus the double surface treatments along different directions visualize the nonuniformity of rubbing, supplying a tool to examine the condition of the rubbing machine used including buffing cloths.

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