Recently, the display of liquid crystal having the blue phase have been studied more intensively because it has many merits such as wide viewing angle without compensation films, very fast switching response time, and no need for the alignment layer and the rubbing process. First, we confirmed the feasibility of the blue phase liquid crystal display by means of polymer stabilization in the test cell. Even though we could get a wide temperature range that shows the blue phase, there were still problems such as the high operation voltage, hysteresis so on. In 2008, by developing and applying new technologies for improving these characteristics, we successfully fabricated a new kind of the liquid crystal display using the blue phase for the first time in the world.

We perform optical, surface anchoring, and textural studies of an organo-siloxane "tetrapode" material in the broad temperature range of the nematic phase. The optical, structural, and topological features are compatible with the uniaxial nematic order rather than with the biaxial nematic order, in the entire nematic temperature range -25 °C < T < 46 °C studied. For homeotropic alignment, the material experiences surface anchoring transition, but the director can be realigned into an optically uniaxial texture by applying a sufficiently strong electric field. The topological features of textures in cylindrical capillaries, in spherical droplets and around colloidal inclusions are consistent with the uniaxial character of the long-range nematic order. In particular, we observe isolated surface point defects - boojums and bulk point defects - hedgehogs that can exist only in the uniaxial nematic liquid crystal.

We investigate the origin of "secondary disclinations" that were recently described as new evidence of a biaxial nematic phase in an oxadiazole bent-core thermotropic liquid crystal C7. Using an assortment of optical techniques such as polarizing optical microscopy, LC PolScope, and fluorescence confocal polarizing microscopy, we demonstrate that the secondary disclinations represent non-singular domain walls formed in a uniaxial nematic phase during the surface anchoring transition, in which surface orientation of the director changes from tangential (parallel to the bounding plates) to tilted. Each domain wall separates two regions with the director tilted in opposite azimuthal directions. At the centre of the wall, the director remains parallel to the bounding plates. The domain walls can be easily removed by applying a moderate electric field. The anchoring transition is explained by the balance of (a) the intrinsic perpendicular surface anchoring produced by the polyimide aligning layer and (b) tangential alignment caused by ionic impurities forming electric double layers. The model is supported by the fact that the temperature of the tangentially tilted anchoring transition decreases as the cell thickness increases and as the concentration of ionic species (added salt) increases. We also demonstrate that the surface alignment is strongly affected by thermal degradation of the samples. This study shows that C7 exhibits only a uniaxial nematic phase and demonstrates yet another mechanism (formation of "secondary disclinations") by which a uniaxial nematic phase can mimic a biaxial nematic behaviour.

Highly uniform thin-films of zinc-indium-tin oxide (ZITO) semiconductors were formed using solution process with wet-annealing at a low temperature of 250 °C. The solution-processed ZITO thin-film transistors with a top-gate staggered structure were fabricated to exhibit field-effect mobility of 2.04 ± 0.28 cm2/Vs at saturation region, threshold voltage (Vth) of 2.15 ± 0.75 V, subthreshold slope of 0.27 ± 0.14 V/dec. and excellent reliability (ΔVth = −4.35 V) for negative bias temperature illumination stress. Based on the performance, a 10.1 in. full-color liquid crystal display was demonstrated by the optimized full photolithography process.

Sung-Tae Shin (2012) Emergence of a novel optically isotropic transient state with low frequency in a blue phase liquid crystal mixture, Liquid Crystals, 39:2, 231-237,The electro-optical hysteresis characteristics in a blue phase liquid crystal system showing multi-domain platelet type body-centred cubic (BP-I) structure at different levels of applied electric field have been investigated. The BP-I state possesses a large degree of hysteresis due to its compact body-centred cubic structure. The hysteresis behaviour is discussed in the context of simulation and theoretical studies reported earlier. When the cell is driven with a low frequency square wave, a novel optically isotropic state with high value of the Kerr constant has been observed. Hysteresis and response time both show relatively lower values in this state with respect to the multi-domain BP-I state.