Kazuyuki Sunohara

A novel class of materials for ferroelectric liquid crystals containing siloxy chain end groups

Abstract Novel liquid crystals containing a siloxy chain as an end tail group instead of an alkyl chain were synthesized. The substitution effects were studied for ferroelectric liquid crystal materials. It was found that the temperature range for the chiral smectic C phase was reduced and shifted to lower temperature in comparison with the analogous alkyl chain derivatives. The crystallinity of the siloxy chain derivatives decreased and cholesteric phases were not observed. The influence of siloxy chains on ferroelectric liquid crystal properties, especially spontaneous polarizations and tilt angles, also greatly depended upon the mesogenic group structure. The X-ray diffraction results showed that the end tail group occupied a larger thickness in the chiral smectic C layer for the siloxy chain derivative than that for the alkyl chain derivative.

Mesophase Transition of Series Materials Containing Fluorene, Fluorenone and Biphenyl Structures with Chiral End Groups

Abstract S 2-alkoxyfluorene-7-carboxylic acid 4-(2-methylbutoxy)-phenyl ester and S 2-alkoxyfluorenone-7-carboxylic acid 4-(2-methylbutoxy)-phenyl ester were synthesized and the effects of mesogen modification or substitution of biphenyl with fluorene and fluorenone group in a mesogen core were studied to obtain a wide temperature range for the SmC* phase. It was found that the SmA phase was rather stabilized by a fluorene substitution, though the thermal stability of the SmC* phase decreased in comparison with the data for biphenyl derivatives. On the other hand, by a fluorenone substitution the SmA phase stability decreased markedly and the SmC* phase stability increased. These results could be explained by two factors. 1. Enhancement in attractive intermolecular force by increasing polarizability of fluorene, compared with biphenyl. 2. Enhancement in induction force due to the dipole moment of the carbonyl group in the fluorenone.

13.4: A 20.8-inch WXGA Full Color AMOLED Display by Integrating Scattering Reflector with Micro-Bumps

In order to improve light extraction efficiency from organic light emitting diodes (OLED), we report a novel structure of top-emission OLED by integrating a scattering reflector with micro-bumps into the substrate. The mechanism of light extraction has been investigated by evaluating the dependency of flux on the shape of the micro-bumps. It was confirmed that the scattering effect of the micro-bumps improves the light extraction of OLED. Moreover, the scattering reflector has been applied on a 20.8-inch WXGA full color AMOLED display. This is the worlds first report that actually proves a light extraction technology, integrating scattering reflector, applied on AMOLED display.

36.3: An Organic Light-Emitting Diode with Highly Efficient Light Extraction Using Newly Developed Diffraction Layer

In order to improve light extraction from an organic light emitting diode (OLED), a novel structure of a top emission OLED was proposed by applying the diffraction layer. We have achieved 1.65 times higher light extraction efficiency in case of electroluminescence (EL), and 2.37 times in case of photoluminescence (PL).

The novel texture of a liquid crystal induced by poly-γ-benzyl-L-glutamate chemical reaction alignment (CRA) film

Poly-γ-benzyl-L-glutamate (PBLG) when treated with a silane coupling agent on a glass surface forms a molecular oriented film; a new liquid crystal texture induced by the α-helical structure of PBLG attached to the substrate surface is observed.