By an appropriate combination of mesogenic polymer stabilization and special rubbing technique, we succeeded in fabricating defect free FLCD exhibiting continuous grayscale operation with high contrast ratio of 700:1. This device is called PSV-mode FLCD. Using this device, we fabricated a field sequential full color LCDs with 4 inch diagonal, SVGA(800*600), 254ppi specification and good color gamut.

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For the application to projection displays, we have investigated the LC alignment control on a new inorganic vertical alignment film having low-k property resulting from its porous structure.By using the inorganic vertical alignment film combined with a SiOx oblique evaporation method, we succeed in generating uniform pretilt angle as high as 10 deg.

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The control of vertical alignment with small pretilt angle using a photo-alignment method has been expected to become a promising liquid crystal (LC) alignment method due to its dust and defect-free nature. In this paper, detailed studies on photo-alignment control of LC using a vertical alignment film are carried out under various preparation conditions of the film (baking temperature, film thickness). As the result, we find that effective generation of pretilt angle by photo-alignment method is possible by reducing the thickness of vertical alignment film.

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The composite technique of the low-angle gradient shaving preparation of a thin film with the polarized micro-Raman spectroscopy successfully determines the depth-dependent molecular orientations for WV films, optical compensation films for TN-mode LCDs. The situation is directly observed that the orientation of the polymerized discotic materials (PDM) is changing within the layer consisting of the PDM itself. It has been elucidated that the PDM skeletons are oriented with a varied degree of distribution, and that, as an average orientation direction, the PDM skeletons gradually stand upright towards the surface.

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Voltage holding ratio (VHR) is one of the most important parameters which influences not only the display characteristics but also the durability of LCDs. In this paper, we investigated the influence of molecular alignment of liquid crystals on VHR. The VHR varies largely depending on the molecular alignment of liquid crystals, even if the same liquid crystal materials and the same alignment material have been used. This seems to be caused by the dielectric loss which is based on the phase lag of dynamic behaviors of LC molecules in the middle of the cell and in the vicinity of the alignment surface.

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Metal nanoparticles doped TN-LCDs exhibit frequency modulation response with a sensitivity to a high frequency component of the applied voltage accompanying the response times of several mill-seconds to several hundreds micro-seconds. In particular the FM-TN-LCD exhibits an enhanced effect in the over driving, where a critical damping is realized depending on the driving waveform. We also report the switchability of FM-TN-LCD.

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OCB-mode is promising for the LCD-TV because of its significance such as fast response and wide viewing angle. One of the remained subjects of this mode is to stabilize the bend state in the dynamic drive. We have investigated this problem and have clarified the difference between static drive and dynamic drive. From the result, we have clarified the stable condition of dynamic drive.

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Alignment treatment to create nucleus for splay-to-bend transition is discussed. Crossed directional two rubbing can control the desired directions of liquid crystal by changing rubbing strengths. By using this method, right- and left-handed twist alignments can be formed, and the nucleus inducing splay-to-bend transition is successfully created.

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We improved viewing-angle property of the OCB cell by using a circular polarizer, which we call advanced OCB mode. This paper describes the mechanism of the improvement in the view point of optical compensation and the fundamental characteristics of the advanced OCB mode LCD.

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We have investigated the viewing angle characteristics of MVA-LCDs with circular polarizers. Main attention is paid to finding the panel configuration showing the wide viewing angle property, which is optically compensated only by using uniaxial optical films. The simulated results show that relatively good viewing angle characteristics are obtained by using l/2 and l/4 films.

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We studied the viewing angle property of hybrid color VA-LCD mode. We clarified that both a self-compensation effect of a reflective structure and a magenta CF effect contribute the improvement of the viewing angle property.

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We developed Double-Faced TFT-LCD having only one LC panel and one lighting system. It works as a transmissive-type LCD for a front side observer and as a reflective type LCD for a backside one at the same time. Because it has only one LC panel and one lighting system, the thickness, the weight and the cost will be decreased to 1/2 compared to a conventional LC module having two LC panels and two lighting systems.

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Thermally enhanced photoinduced reorientation behavior of liquid crystalline polymethacrylate films comprising 4-methoxyazobenzene side groups with different spacer length was investigated based on an axis-selective cis-to-trans photoisomerization using linearly polarized (LP) 633 nm light and thermal amplification of the photoinduced anisotropy. A high order in-plane reorientation parallel to polarization (E) of LP 633 nm light was accomplished regardless of the spacer length. We found that the initial orientation of the mesogenic groups played an important role for the reorientation, and clarified the reorientation mechanism by means of polarization absorption spectroscopy.

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We investigated optical control of light-scattering properties in liquid-crystal suspensions by means of photoisomerization of azobenzene derivatives. Liquid-crystal suspensions, azobenzene-containing nematic liquid crystals dispersed with small polymer particles, scattered light strongly in nematic phase. This would be attributable to polydomain structures and large birefringence of liquid crystals. The light-scattering state turned into a transparent one when the polydomain structures were erased by trans-to-cis photoisomerization of the doped azobenzene dye in which the nematic-to-isotropic phase transition was induced. The transparent state could be switched to the initial light-scattering state by a recovery of the nematic phase where the cis-to-trans photoisomerization occurred.

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Homeotropically aligned azobenzene liquid-crystalline elastomer (LCE) films were prepared and investigated in terms of the photoinduced bending behavior. The LCE was obtained by in-situ photopolymerization in a glass cell with homeotopically alignment. Upon irradiation of UV light which induces photoisomerization of the azobebzene moieties, the film bent away from the UV light and reverted to the initial state when irradiated at visible light, contrary to the bending behavior of a homogeneous film. This can be explained by a different volume transformation.

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A flexible liquid crystal hologram was prepared as a novel type of holographic materials. Polycarbonate films covered with a polyimide were employed as a substrate, and toluene solution of a polymer azobenzene liquid crystal (PALC) was coated on the rubbed substrate, resulting in a flexible PALC film. We attempted the formation of gratings and holographic image storage of 3-D objects into the flexible film. A clear and bright 3-D image was successfully reconstructed even in the bent film. This indicates that the holographic diffraction grating is formed in the flexible PALC film.

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We report polarization analysis of higher order diffraction beam from polarization gratings in photoreactive polymer liquid crystals (PPLCs). The polarization gratings are created from the photoreaction of PPLCs and finally induced molecular reorientation by annealing. In this work, investigations were carried out on two types of polarization gratings fabricated by different method and PPLCs. Results of the polarization analysis of two polarization gratings in the higher diffraction orders were explained by general diffraction theory described by Jones matrices.

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Polymer azobenzene films containing various contents of a tolane moiety with large birefringence were prepared. Two linearly polarized beams of an Ar+ laser (488 nm) were interfered in the film, and the light intensity of the first-order diffraction of a He-Ne laser beam (633 nm) was measured. In the film with thickness of 100 μm, the diffraction efficiency reached 99.2 % when photoirradiation was performed at 200 mW/cm2 for 13 min. The maximum diffraction efficiency was significantly influenced by the content of the tolane moiety.

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Photopolymerization of ferroelectric liquid-crystalline monomers was carried out under an electric field. Upon photoirradiation of an Ar+ laser beam at 488 nm, a monomer mixture in a 0.002 mm cell was polymerized and the initial molecular alignment was stabilized. Next, two beams at 488 nm were interfered in the cell, and the light intensity of the first-order diffraction light of a He-Ne laser beam at 633 nm was measured. The diffracted light appeared due to the grating formation. By applying an electric field, the intensity of the diffraction light increased, indicating a change in alignment of the unreacted monomers.

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The photorefractivity of polymer-stabilized ferroelectric liquid crystal (PS-FLC) using photoconductive monomer was investigated. The PS-FLC materials exhibited monostable and bistable electrooptic effect. The photorefractivity of PS-FLC material was investigated by two-beam coupling experiments. While the monostable material showed stable photorefractivity, the bistable one showed very instable photorefractivity.

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The photorefractive effect of FLCs under an alternating electric field was investigated through two-beam coupling experiments. Under an AC electric field, the two-beam coupling gain coefficient was almost independent of the external electric field strength higher than + or -0.1V/mm.The behavior is different from the photorefractive effect of FLCs under a DC electric field. Under a DC electric field, the two-beam coupling gain coefficient decrease with the external electric field. The grating formation time under an AC electric field was found to be faster than the time under a DC electric field.

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Polymer films containing a donor-accepter type azobenzene moiety were prepared and formation of gratings based on a photoinduced change in refractive index was explored. When two linearly polarized beams of an Ar+ laser (514 nm) were interfered in the CB30AB5 film (film thickness: 0.25 mm), the diffraction beam based on Bragg diffraction appeared immediately. The maximum diffraction efficiency reached 98 % upon photoirradiation at 100 mW/cm2 for 6 min. It was clearly observed that the response time became shorter with an increase in the light intensity of the writing beams, maintaining the high diffraction efficiency. Furthermore, holographic multiple data storages in the CB30AB5 film were demonstrated.

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w-Alkyl-w*-akkynylquaterthiophene derivatives of smectic liquid crystals exhibiting smectic phases below room temperature, are synthesized and their liquid crystallinity and charge carrier transport properties are characterized.Propylhexynylquaterthiophene exhibits highly ordered smectic phase down to -20 oC in cooling process. Hole mobility at room temperature is 0.1 cm2/Vs which is comparable to those of aromatic molecular crystals.

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We have found that liquid crystal solvents can control single crystal morphology of segregated pentacene organic semiconductor, which is expected to have high charge mobility. Original pentacene powder was dissolved in heated liquid crystal, and the solution was confined in a cell with polyimide alignment layers. Different-morphologies pentacene segregation was confirmed in cooling the cell with various pentacene concentration ratios. The rubbing process of the alignment layer promoted growth of large lozenge single crystals in the cell. The lozenge morphologies were classified as pyramidal and thin flat plate shapes. The flat one is useful for electronic device applications.

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A liquid crystal (LC) lens driven by two voltages is reported. An operating voltage on an electrode with a hole in the center is fixed and a controlling voltage on a transparent electrode controls the focal length of the LC lens. The range of the variable focusing power is very large covering from approximately 0.8 to 10.7 diopters. In the entire focus range the LC lens preserves its high optical quality.

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Polarization independent electrically tunable Raman-Nath phase diffraction grating has been fabricated in a very simple technique using photo-curable liquid crystals. The structure consists of alternating stripe of twisted-nematic liquid crystal domains and polymerized homeotropic ones. The diffraction efficiency can be tuned by an applied electric field, and is independent of the incident polarization particularly above an electric field to make a Frederiks transition.

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Microscale liquid crystal (LC) molecular alignment patterns are formed using a microrubbing process, and we apply the LC cells with the microscale LC molecular alignment patterns to various diffractive optical devices. The controlling method of the phase of light only by distributing the azimuthal angle of the LC director is proposed. Optical properties of fabricated LC diffractive optical devices with the high diffraction efficiency are reported.

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A flexible field-sequential-color matrix display has been developed using an A4-sized plastic-substrate-based monostable ferroelectric liquid crystal panel, in which image pixels are driven by an active matrix technique using an outer switch transistor array circuit. The black matrix and transparent electrode patterns were formed on a large flexible plastic substrate by transfer method, and then the composite film of the liquid crystal and micropolymers suspending the substrates was formed by printing and phase separation processes. The color display operation with 24 x 16 image pixels was obtained by illuminating the image pixels uniformly with intermitted light from three-primary color LEDs and by driving the pixels according to each color illumination.

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The fabrication of tunable photonic crystals responsive to external stimuli was studied. The inverse opal structure of SiO2 was fabricated and their voids were infiltrated with liquid crystal, which was azobenzene derivative (AzoLC). The optical properties were evaluated by means of the reflection spectra. The changes in the peak position and intensity were observed after UV light irradiation. It should be caused by the photoisomerization of AzoLC leading to phot-induced phase transition from nematic to isotropic phase. The application as display devices was also studied. It was confirmed that photomask pattern could be recorded with UV light irradiation through the mask. Such material has an advantage that the recorded image could be observed without polarizers.

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Photonic crystal structures were formed by polymer particles containing azobenzene moieties and their optical responsiveness was investigated. A Bragg diffraction peak due to the periodic structure was observed in the PME3-30 film in the reflection spectrum. A change in the intensity of the diffraction peak was induced by irradiation of a linearly polarized beam at 488 nm. The observation of the film by SEM revealed the adhesion of the polymer particles induced by photoirradiation.

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A novel main-chain liquid-crystalline polyester (MLCP) containing an oxadiazole moiety as an electron-transporting unit and a carbazole moiety as a hole-transporting unit was designed. The MLCP, P10-DOXDCz, was synthesized by the transesterification of N-hexyl-3,6-di[2-([1,3,4]oxadiazol-5-yl)-4-methyl benzoate]carbazole and 1,10-decanediol. P10-DOXCz showed a nematic phase. P10-DOXDCz emitted intense blue fluorescence with a maximum at 425 nm ( ff = 0.74) in a solution and at 439 nm in a thin film. Polarized emission of fluorescence was observed in a nematic phase, and order parameters estimated by the polarized emission was 0.10.

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We have investigated defect mode in one-dimensional (1D) photonic crystal (PC) with in-plane switchable nematic liquid crystal (NLC) defect layer. Defect mode peaks appeared in photonic band gap and could be electrically controlled upon applied electric field based on the change in orientation of NLC molecules. Defect mode intensities changed with an azimuthal angle between direction of NLC molecules and polarization angle of the analyzer. At defect mode wavelength, the light propagating through 1D PC with NLC defect layer is polarized along extraordinary or ordinary light axes of the NLC in the defect. Polarization angle of 1D PC with in-plane switchable NLC defect can be controlled upon causing molecular by applied electric field.

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Polymer-dispersed liquid crystals (PDLC), which consist of micro-sized nematic liquid crystal droplets dispersed in a polymer matrix, possess light scattering effect. In random media, light waves undergo a complicated multiple scattering process, and various phenomena such as random laser action have been reported. In this presentation, the optical properties in dye-doped PDLCs are studied. It is found that dye-doped PDLCs exhibit unique and interesting optical properties such as strongly temperature-dependent threshold for gain narrowing and emission band width.

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Recently, the defect mode in CLCs has been studied for lasing at low threshold. We have already investigated the lasing characteristics from a dye-doped 2micro -nematic layer sandwiched by two Polymer CLC (PCLC) films. The polarization characteristics of the phase retardation defect mode emission is different from that of single layer and twist defect mode systems in CLCs In this study, we demonstrate an interesting phenomenon caused by thicker anisotropic layer such as 100micro.

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Although a large number of studies have been made on low-threshold laser oscillation using the photonic structure in chiral nematic liquid crystals, little is known about the stability. In this report, band-edge lasing of liquid crystal samples doped with common laser dyes was carried out, and the stability was investigated. Coumarin doped sample that requires UV light (370 nm) excitation lased only a short time. On the other hand, DCM and pyrromethe pumped by visible light (530 nm) was lased over the long time. Reducing the threshold pumping energy by optimization of a sample, we demonstrated long-lifetime laser oscillation at least 10^7 or more shots.

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Cholesteric liquid crystal (CLC) which has a periodic helical structure with a periodicity of the optical wavelength can be regarded as a one-dimensional photonic crystal. We made a CLC rod using a photo-polymerization technique in which the photo-polymerizable CLC was exposed to ultraviolet light passing through a patterned mask. A laser action at the edge of the photonic band gap was demonstrated along the helical axis of dye-doped CLC rod.

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[in Japanese]

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We have studied transport of nano-sized colloidal particles dispersed in lyotropic lamellar phase of a nonionic surfactant over wide time scale by electrophoretic light scattering, dielectric spectroscopy and direct observation under a microscope. The temporal hierarchical structure is found in transport process of particles, which is not observed in water. The mechanism of transport process in lyotropic lamellar phase is discussed by their special hierarchical structures.

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We construct a simple phenomenological model of collective molecularrotation in chiral liquid crystal monolayers, regarding it as a 2Danalogue of Lehmann-type rotation. Results of numerical simulationsbased on this model are consistent with the experimental observationqualitatively, especially the winding/unwinding phenomena near theboundaries (defect lines, walls).

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Chiral LC monolayers on glycerol surface exhibit unidirectional precession motion driven by transmembrane water tranport. The rotational speed linearly depends on both molecular chirality and mass of water transfer. The result gives a new approach to molecular motor.

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We theoretically study phase transitions of a polymer threading through a pore imbedded in a membrane. We focus on the coupling between a partition of the polymer segments through the membrane and a coil-globule transition of the single polymer chain.

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We have found the new types of photonic liquid crystal, SmBPIso phase,which shows the uniform isotropic iridescent color strongly dependent onthe concentration, chirality and temperature for the first time. SmBPIso has both the finite local order parameter of the helix of the orientation and the smectic layer simultaneously, but spontaneously achieves complete isotropic nature in optical wave-length without any characteristic discontinuity in mesoscopic length scales. It was confirmed by visco-elastic measurement that the SmBPIso should be originated from the anomalous softening of the smectic layers due to the freezing effect on the molecular fluctuation induced by the introduction of the connection of the molecules in chiral twin and monomer commensurate mixture. We expected that the random distribution of the locally distinct helix in 3-dimensional space can be stabilized by the apparent elastic long-range interaction "field" produced by the deformation of the smectic order together with helixes themselves.

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We demonstrate the prototypes of nano-structured liquid crystal system to disperse the supra-molecular aggregates in the liquid crystal. These aggregates play role on the permanent defect in the liquid crystalline order, which has well controlled length scale and density. These permanent defects create the elastic distortion in the surrounding liquid crystalline medium, and produce the long-range elastic interaction between adjacent aggregates, because the spatial distribution of the defect must be rearranged to minimize the total elastic free energy. On the another point of view, molecular chirality is unique character for the biological systems such as DNA, lipid, cholesterol etc., but the helical structure hardly ever appear in macroscopic length scales in lyotropic or biological system. We have found the novel liquid crystal emulsion system,"BLT" liquid crystal which has macroscopic helix due to supra-molecular chirality.

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Liquid crystal(LC) display should possess the solid anchoring surface except for the free standing films, because it is necessary not only for the mechanism of the display device, but also the holding the fluid LC materials. Here, we invented the novel principle for LC display. Both axis and threshold less in-plane switching mode with memory in any direction can be realized by introducing the spontaneous complete wetting liquid-LC interface on the glass substrate of the cell. The complete wetting interface has been achieved by the suitable modeling of the phase separated LC mixture, such as polymer-LC mixture, with special types of the amphiphiles to activate the interface of liquid-LC. Both LC and solvent molecules can diffuse across the liquid-LC interface, because there is only difference in the concentration and the order parameter. Thus, these surfaces have intrinsically unique physical nature in comparison with the solid surfaces, such as spontaneous complete flatness in molecular scale or free fluctuation motion in the vicinity of the interface.

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Phase transitions between isotropic, nematic, and smectic phases of McMillan model sandwiched by parallel solid walls are discussed. The solid walls are assumed to be homeotropic anchoring walls, i.e., at the interfaces, the walls force the liquid crystalline molecules to stick perpendicular to the walls.The liquid crystalline systems show a non-spontaneous nematic phase induced by the homeotropic anchoring walls; such a phenomena is similar to the appearance of non-spontaneous nematic phase under external fields.The phase transitions of the liquid crystals under the influence of the walls are shown to be qualitatively similar to the phase transitions under the external fields.

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In FLC cells fabricated using same alignment films in which the rubbing directions were set anti-parallel, zigzag defects always appear because the energies of two types of chevron structures are equivalent. In this report, we formulate a new idea for fabricating zigzag defect-free FLC cells to which the energy difference is given by adopting a combination of two alignment films which have different surface anchoring energies.

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We have already succeeded in observing the orientational fluctuations in a homogeneously aligned nematic liquid crystal with a high-speed video camera. In this study we expand the frequency range of measurements with a faster video camera. It is shown that the relaxation rates are proportional to the square of the wavelength in a wide range.

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The investigation of the surface alignment of liquid crystal multilayers evaporated on photoalignment polyimide film was carried out by means of the novel three–dimensional surface profiler instrument and the optical polarizing microscope. The purpose of this investigation is to visualize a microscopic image of the monolayer arrangement of liquid crystal molecules in contact with the surface of photoinduced polyimide film. From our experimental study, photoinduced anisotropy of partially photo–exposed polyimide film can be visualized as a topological image of liquid crystal multilayers. It seemed that the topology of liquid crystal multilayers is indicating the orientational distribution of liquid crystal molecules.

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A novel method of evaluation of polar anchoring strength is proposed. Anchoring strength is evaluated from measurement of the optical retardation measured by the symmetric-oblique incident transmission ellipsometry (SOITE). By using the SOITE, anchoring strength can be evaluated accurately without the effect of multi-beam interference (MBI). The advantage of our method was shown experimentally.

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UV light irradiation and plasma discharge treatment were carried out for polymer films such as polymide. Surface physical property of these modified polymer films was evaluated and influence on liquid crystal molecular orientation on the films treated by conventional rubbing technique and magnetic field orientation method (MOLCA) were examined, experimentally. As the result in case of plasma treatment, wettability of polymer films was improved, and the liquid crystal pretilt angle lowered.

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