It is known that nematic director slightly deviates from the rubbing direction due to long period driving of IPS mode panel by AC electric field . Our quantitative results of long period measurement are presented in this paper on a base of a model of interaction between surface of PI alignment film and LC molecules. We found that the surface rheology of PI alignment film is one of the most important factors for this deviation phenomenon.

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We have developed alignment-film material. Our target is the liquid crystal display in homogeneous-molecular-alignment mode, for example In-plain-Switching (IPS) mode and Fringe-Field-Switching (FFS) mode. It will become a high contrast if a black level is improved. The light leakage of various scales worsens a black level. The cause of light leakage is in a rubbing process. We developed CCD image-processing technology, in order to evaluate light leakage. This technology can clarify various light leakages. We were able to understand clearly about the relation between light leakage and black level.

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The authors succeeded in reducing 70% of TN-LCD decay time by using the ultra short pitch LC materials which forms STN mode at conventional conditions. It was found that TN molecular arrangement can be formed by applying electric voltage to STN mode under certain condition and the obtained TN mode can be maintained for the period depending on the pretilt angle magnitude. The TN mode can be stabilized by the photo polymerization process, which can also shorten the decay time. The response time reduction was also effective at -20 degree

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Here we present a newly developed reverse twisted nematic liquid crystal display (RTN-LCD) whose performance is quite different from one which we have presented so far. The panel structure is almost the same as previous RTN-LCD except that the pretilt angle is set low in this case. It turns out that the electro-optical characteristics of the present low pretilt angle RTN-LCD is much steep enough to realize the maximum duty ratio of 1/480 for multiplex drive. As an advantage to a conventional STN-LCD, this low-pretilt angle RTN-LCD shows a good white off-state without optical compensation, as is needed for a conventional STN-LCD to reduce a blue or yellow color of its off-state. Thus, low-pretilt angle RTN-LCD has the merit in viewpoint of product cost as compared to conventional STN-LCDs.

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We have developed novel time-sequential 3D systems. In order to get really clear 3D images, fast response OCB mode was introduced into both of 15.4 inch WXGA panels and active shutter glasses. To make brightness even better, new blinking backlight control technique was also applied. These technologies enable us to provide crosstalk-free and high brightness 3D images.

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We have developed an advanced VA mode where liquid crystal materials are driven by a combination of a lateral field and a vertical field. A wide viewing angle without color wash-out in oblique directions and a fast response between all gray scale levels are obtained by an electrode design.

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We have developed novel functional films which simultaneously reflect and emit light using fluorescent dye doped cholesteric liquid crystals (CLCs). Since both backlight and ambient light can be fully utilized, an energy efficient liquid crystal display (LCD) is highly expected. We have proved the R,G,B three films' functions using a simple LC cell experimentally. We have also applied the films to a commercially available LCD and the resultant display showed a clear image even under direct sunlight condition which image a normal LCD cannot achieve.

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The stability and reproducibility are the main difficulties when controlling continuously the intermediate pretilt angle of liquid crystal between homogeneous planar and vertical by using the blended polyimide films of two types, one being used for planar liquid crystal alignment, and the other being used for vertical alignment, in proper mixing ratio. In this study we show that the improvement of film fabrication process and the addition of nanoparticles to the polyimide alignment material can settle these difficulties, expanding the margin of the mixing-ratio sensitivity of these two polyimides.

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Electro-optic effects based upon the electric-field-induced isotropic-nematic transition were investigated using test cells with an appropriate electrodes-configuration and different substrate-surface treatments. Sufficiently large and extremely fast optical-transmittance change was observed between the isotropic phase and the field-induced nematic phase. This verifies its applicability to novel liquid-crystal displays featuring fast switching less than 1msec.

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It is necessary to form polymer layer in PSD and net work polymer structure in blue phase LC. And it is important to controll polymerization of monomer suspended in LC because the residual monomer gives bad influence to LCD. But it is difficult to analyze polymer and residual monomer in LC. It is cleared that it is possible to measure the degree of polymerization and monomer using micro infra red spectroscopy and micro sampling mass spectroscopy.

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In a system of disk-like molecules, we see columns composed of disk-like molecules. Computer simulation predicts existence of cubatic structure composed of columns of disk-like molecules. The column structure is a candidate of conductive path for future organic electronics material. In this study we discuss affinity of hard disk-like molecules for formation of column structure using theory and simulation.

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I introduce a theory to describe the phase separations in mixtures of a liquid crystal and a rodlike polymer.

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We are proposing a novel solution process to fabricate pentacene (PEN) thin-films from PEN-containing liquid-crystalline (LC) solutions. % By using LC solution, we intend to control PEN alignment via self-alignment nature of LC phase. We here report MD simulation study of the structure of this PEN-containing LC solution. We found that the pentacene in the LC solvent was parallel aligned to the solvent LC orientation in average.

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Langmuir monolayers at an air/water interface have been studied for understanding the properties of two-dimensional (2D) system. While smectic liquid crystals (LCs) spontaneously form stable LC monolayers, 2D system of nematic LCs has not been found so far; the optical anisotropy is not detected when LC molecules align on the water with its long axis being parallel to the interface. Our purpose of this study is to analyze and compare the orientational correlation of LC molecules in 2D smectic monolayer and that in 2D nematic one by molecular dynamics (MD) simulation.

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Chiral liquid crystal (LC) films are known to exhibit unidirectional orientational rotations under some transmembrane mass flow, called Lehmann rotation[1]. In the case of free-standing films, not only the orientational rotation but also the flow of LC molecules is also induced by transmembrane mass flow. In order to detect the in-plane flow, we put zirconium dioxide (ZrO2) particles on chiral free-standing films, and measured the driving force submitted to the particle via Lehmann effect. In this report, we especially focus on the induced flow in SmA* free-standing films.

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We have proposed a one-dimensional simple model which combines the motion of the upper plate of a liquid crystal cell and the flow of a liquid crystal. The model is able to predict qualitatively the motion of the upper plate. Furthermore, it is clarified that when the electric field is released, the molecule at the middle position between two plates returns to the initial angle completely at 1 Hz of the frequency of the applied voltage, it does not return to the initial angle but it takes approximately 40 deg at 10 Hz, and it oscillates between 90 deg and 96 deg at 100 Hz. The kickback effect is dominant in this oscillation with small amplitude.

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We prepared a chiral S-shaped oligomer, (R)-3-methyladipic acid bis (6-(2-(6-(4-(4-(4-hexylphenyl)-2,3-difluorophenyl)phenyloxy)hexyloxy)phenyloxy)hexyl) ester, and investigated the chirality-dependent properties. The compound showed a chiral nematic phase with a wide temperature range. The helical pitch induced in the N* phase was about 3 µm, and it is independent of the temperature. A periodic striped pattern was observed in the N* phase of a homogeneous aligned sample. The pattern formation depends on the cooling rate and the cell gap. On the other hand, the corresponding racemic oligomer did not exhibit such a striped pattern. Coupling between twisting power of the chiral oligomer and alignment force is thought to produce the periodic pattern.

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We synthesized a novel bromo-substituted dichiral smectic liquid crystal. From the dielectric properties, texture observation and electrooptic measurements, it is found that several subphases appear between ferro- and antiferroelectric phases. Comparing the phase sequence of homologues without bromine, we discussed the effect of lateral group on the phase structure.

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Bolaamphiphilic liquid crystals (BALCs) with chiral units were synthesized. The thermal and orientational properties of BALCs were examined. BALCs exhibited chiral nematic, smectic A and chiral smectic C phases. In the smectic A and smectic C phases, a monolayer structure was proposed as a possible packing model. Hydrogen bondings at both terminals in BALCs act effectively in forming the smectic layer structure.

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Amphiphilic liquid crystalline materials (ALCs) with a mesogenic core were synthesized. Phase transitions and orientational properties of ALCs were examined by polarizing microscopic observation, DSC and X-ray diffraction measurement. Nonionic ALCs formed smectic A and smectic C phases. Ionic ALCs exhibited a smectic A phase with enhanced thermal stability when compared to nonionic ALCs.

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A homologous series of chiral twin liquid crystals were prepared, and the effects of spacer lengths, terminal chain lengths and mesogenic core structures on the liquid-crystalline phase transition behavior were investigated. All the oligomers possessing a phenylpyrimidine core were found to exhibit a ferrielectric smectic C phase with a wide temperature range. The phase sequence exhibits a pronounced odd-even effect as parity of the spacers is varied. Furthermore a direct transition from Iso to ferri was observed for a chiral oligomer possessing a 2-phenyl-5-alkoxypyrimidine core.

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We found that chiral dopants of cyclic dimer molecules with chiral spacer as an optically active moiety showed large helical twisting power for a nematic liquid crystal. The chiral dopant showing the largest helical twisting power of 61 can induce a helical pitch comparable to the visible light wavelength at small fraction of 5wt%.

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We measured vibrational circular dichroism (VCD) in the mixture consisting of bent-core and rod-like liquid crystals molecules. The results shows the spectral change in the mixture is different from the original bent-core system. We infer that this difference comes from the coexistence of Isotropic and liquid crystal phase (B4 phase) in the mixture around the phase transition. Thermal measurements also support this consideration.

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We report intensive calorimetric studies on the liquid crystal mixtures formed of bent-shaped molecules (BC12) and rod-like molecules (9OCB) using a high-resolution ac calorimetry and a high sensitivity differential scanning calorimetry. The magnitude of the heat anomaly associated with the nematic-smectic-A phase transition sharply decreases and, moreover, a first-order nature disappears with the increase of bent-core molecules. The effect of bent-core molecules on the critical exponent is examined.

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In a frustrated binary mixture system of MC881 and MC452, where the border line between Sm$C_{A}^*$ and Sm$C^*$ in the temperature-concentration phase diagram runs almost parallel to the ordinate temperature axis, we have found a continuous change between them close to the critical concentration. The continuity has been confirmed as an intrinsic property in the bulk by observing almost perfect bell-shaped Bragg reflection bands due to the helicoidal director structure. The temperature variation of peak wavelength of the half-pitch band and, in particular, the characteristic disappearance of the full-pitch band apparently within the Sm$C^*$ temperature region have been simulated with a change in the ratio of ferroelectric and antiferroelectric orderings.

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We have carried out calorimetric and optical investigations on a polymer dispersed liquid crystal system, in which an optically isotropic nematic phase can be observed when the size of the nematic droplet is small. High-sensitivity differential scanning calorimetry measurements revealed a double-peak heat anomaly around the isotropic-nematic phase transition. Moreover, measurements of the small birefringence exhibit a clear jump in accordance with the calorimetric data. Our results indicate that the heat anomaly observed at the higher temperature is generated by the contact between the polymer surface and the liquid crystal molecules.

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Calorimetric study on the effect of the enantiomeric excess on the smectic-C^*alpha (SmC^*alpha) - smectic-C^* (SmC^*) phase transition was carried out using a high-sensitivity differential scanning calorimetry in an antiferroelectric liquid crystal compound. It is found that as the optical purity decreases, the first-order SmC^*alpha - SmC^* transition changes to the continuous behavior through a critical point. Our result indicates that the enantiomeric excess significantly influences the heat anomaly near the transition temperature.

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The configuration of director field in a liquid crystal droplet has the radial or bipolar structure depending on the type of anchoring at the droplet surface. We investigate how a radial nematic liquid-crystal droplet is influenced by a static electric field theoretically. We predict a second-order phase transition to a structure in which the singular point of the radial structure is shifted from the center of the droplet. We will calculate the critical field and the dependence of position of singularity on the electric field.

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6-Alkyl-2-phenylazulene (nPA, n: the number of carbon atoms in alkyl group) have crystal E (CrE) phase as mesophase. DSC experiments on nPA showed the direct phase transition from CrE to isotropic phases. The entropies of fusion of nPA obtained by DSC measurements are almost constant against n. The constant value, however, is larger than the entropies of fusion expected from the previous thermodynamic analysis of the 4-n-alkyl-4'-isothiocyanatobiphenyl, which also show the CrE phase. The largeness suggests that the conformational disorder of the alkyl chain of nPA is partially suppressed in the CrE phase.

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We have succeeded in controlling the pretilt angle of liquid crystal (LC) molecules over the whole range from 0 to 90 deg. by using photo-aligned blend films of azobenzene-containing polyimides (Azo-PIs) with and without side-chains. For the blend films, defect-free uniform LC alignment was obtained in the pretilt angle range of < 10 and > 85 deg. This defect-free range is wider than that (< 5 and > 85 deg.) for pure photo-alignment films of side-chain type Azo-PIs. This result indicates that the azimuthal anchoring strength of the blend Azo-PI film is stronger than that of the pure side-chain type Azo-PI film at least for the pretilt angle range from 5 to 10 deg.

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Liquid crystal (LC) alignment properties of a rubbed polyvinyl-cinnamate (PVCi) surface have been investigated. Some kinds of LC materials without CN and F substances align parallel and others, for example 5CB, align perpendicular to the rubbing direction. Alignment directions of LCs mixing of two types of LC are also clarified on UV exposed and unexposed PVCi surfaces. In addition, we proposed a novel alignment patterning which can be controlled by selecting LC materials.

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We propose rubbing-less liquid crystal (LC) alignment by using high-density poly(methyl methacrylate) (PMMA) brushes. Homogeneously aligned cell consisting of the glass plates with polymer brushes was obtained by applying magnetic field in the plane parallel to the substrates on cooling from a temperature of 120 ºC as high as the glass transition temperature of the brushes to ambient temperature. The orientation direction was changed by in-plane electric field, then recovered immediately on turning off the field, showing that the polymer brushes are effective in anchoring the nematic LC like a rubbed polyimide film.

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Optical retardation R of a retardation film which used for optical compensation of liquid crystal displays (LCDs) is generally obtained from the phase difference D between the fast axis and slow axis of transmitting light. However, the conventional measuring method cannot determine the optical properties of the retardation film such as refractive index, film thickness, director orientation and tilt angle, individually. In this paper, we report how to determine the optical properties of retardation films using ellipsometric parameters which obtained from transmission and reflection measurements.

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The effect of pressure on the structural phase behavior and stability of the cubic phases for three homologous compounds of 1,2-bis(4-n-alkoxybenzoyl)hydrazine having tetradecyl, hexadecyl, and octadecyl groups (BABH-14, -16, -18) was studied under high pressures up to 140 MPa using a WAXD equipped with a hydrostatic pressure system.

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Novel liquid crystals having a fluorinated allyl oxy (-CF=CFCF₂O-)linlage have been prepared by using perfluoroallylfluorosulfate (PFAS:CF₂=CFCF₂OSO₂F).
It has come to light that these novel liquid crystals have suitable properties for AM-LCDs.
Now we present the synthetic method and physical properties of these novel liquid crystals.

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Previously, we reported the mesomorphism of alkali metal carboxylates having neither a rigid core in the center nor flexible long chains. They were named as "flying-seed-like liquid crystals". Recently, it was reported that the phthalocyanine derivative (1) having no long chains but bulky triphenylmethylphenoxy groups exhibits liquid crystalline phase at high temperatures. However, this mesophase has never been established in detail. We speculated that this phthalocyanine derivative was also one of flying-seed-like liquid crystals. Therefore, by using temperature-dependent X-ray diffraction technique, we have investigated the mesophases of (1) and novel related phthalocyanine derivatives having various bulky groups. As the result, they exhibited a columnar mesophase.

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In the present study, we have developed organic-inorganic hybrid dendrimers with thermotropic cubic liquid-crystallinity by hybridization of organic dendrons having an amino-group with CO2H-modified spherical gold nanoparticles with narrow size distribution through formation of covalent bonding. Small angle X-ray scattering, GISAXS, and DSC measurements revealed that the hybrids showed thermotropic cubic phase with a bcc crystal structure in wide range of temperatures. Effect of the generation of the dendrons, the particle size, and the monodispersity on the formation of the thermotropic mesophases has been examined.

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Recently, transflective LCDs pay much people's attention due to their lower power consumption and excellent readability in an out-door environment. But commercial availability of the LCDs are limited because of the complex structures, etc. In this study, we propose a new type of transflective LCDs that have wave guide structures in the LCDs, which leads to simplify the LCD structure (single cell gap). We give preliminary experimental results that demonstrate the usefulness of the proposed LCDs

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In-Plane-Switching (IPS) LCDs are known to show wide viewing angle properties in the EO performance. This display mode has utilized the mechanical rubbing method for LC alignment, but the method has been intrinsically had several drawbacks pointed out so far. In this paper, we have been proposing the method to solve the drawbacks by using the photo-alignment method combined to a polymer-surface-stabilized method and the usefulness of the proposed method is demonstrated showing detailed experimental results.

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We propose and evaluate a new LCD mode using antiferroelectric liquid crystals (AFLCs). This LCD mode utilizes dielectric response of antiferroelectric order; homeotropically aligned AFLCs with short helix have uniaxial property (Dark state) without a field, and the optical birefringence (Bright state) appears under the unwound process by applying an electric field parallel to the smectic layer. By measuring the optical birefringence as a function of the field, we confirmed this LCD mode as expected. It is also found that this LCD mode has fast response of the order of 10~100 us and exhibits continuous gray level .

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Today, an organic thin film transistor (O-TFT) is known to become a key element for realizing flexible display devices. In this study we have directed our attention to a gate insulator, which are one of indispensable elements for O-TFTs. We use a UV-curable liquid crystalline polymer as a gate insulating material, and we report the electrical properties by observing deep carrier trap levels in the insulator using a thermal stimulated current (TSC) method.

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Colloid arrays are promising structures as colloidal analogs of molecules and photonic crystals. One way to effectively manipulate colloidal particles into such arrays is to assemble them in director fields of liquid crystal. We present an approach to generate colloidal arrays in droplets of nematic LC. The patterns of the colloidal arrays depend on the surfactant and the volume fraction of particles.

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We found the novel perforated lamellar-nematic (PLN) phase which has microphase separation of nematic and lamellar phases in the mixture of calamitic and amphiphilic liquid crystals. By exchanging the calamitic liquid crystal of the mixture, we found macrophase separation of nematic and lamellar (N+L) phases appears in lower temperature region of PLN phase with microphase separation. Moreover, we analyzed the difference of the structure and dynamics between PLN and N+L phases using dynamic light scattering and fluorescent diffusion measurements.

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We have prepared a twist nematic elastomer ribbon where the director gradually rotates by 90 degree between upper and bottom surfaces using the chirally imprint method. The ribbon specimen forms a helical ribbon or twist ribbon depending on the width. In addition, the twist and helical pitches markedly vary with temperature.

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This manuscript presents helical mechanoclinic deformation of a main-chain chiral smectic elastomer which is prepared by a cross-linking reaction under twist deformation. The X-ray analysis reveals that the twist deformation induces a layer tilt angle that depends on the handedness of twist. The layer tilt angle in the right-handedly twisted elastomer, of which the handedness is consistent with that of the helix in the chiral smectic C (SmC*) phase of non-cross-linked backbone polymer, is estimated to be up to 16 degrees at room temperature, though that in the left-handedly twisted elastomer is less than several degrees. The experiments provide evidence of chiral coupling between tilt and twist for helical mechanoclinic deformation in the chiral smectic system.

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