Contents

Abstructs of Reviews

Photoresponsive Liquid-Crystalline Gels for Actuators

Makoto NAKANO, Yu YANLEI and Tomiki IKEDA
Ube Industries LTD.
E-mail: 32083u@ube-ind.co.jp

Abstract : Recent studies on stimuli-responsive polymer gels as potential materials for robot actuators are reviewed.In conventional polymer gels such as poly (N-isopropylacrylamide)( NIPA)gels,although they can undergo large shape changes in response to various stimuli, problems such as slow response should be solved for practical uses.Recently,deformable liquid-crystalline gels (LCGs) have attracted great interest,because their deformation arises from a di?erent mechanism, an order-disorder phase transition of LC phases, and thus a fast response is expected in these materials. Furthermore, a photoinduced large contraction has been achieved in azobenzene- containing LCGs due to photochemical phase transition. Most recently, we have even realized a photoinduced fast bending along one direction in the azobenzene -containing LCGs. By using polydomain LCGs and linearly polarized light, directed bending along any chosen direction has also been achieved. These results clearly indicate that the azobenzene-containing LCGs are attractive materials for micro/nano actuators.
Keywords : Organic light-emitting device, Display, Organic thin film, Quantum efficiency, Excited state, Fluorescence, Phosphorescence, Out-coupling efficiency

Progress in Viewing Angle Properties of Liquid Crystal Displays

Takahiro ISHINABE and Tatsuo UCHIDA
Tohoku University
E-mail: ishinabe@ecei.tohoku.ac.jp

Abstract : Viewing angle dependences of contrast ratio and color shift of LCDs have been much improved since the progress of high quality television applications. This paper describes the concept of optical compensation and the fundamental characteristics of the viewing angle property for various LC-modes.
Keywords : crystal display, Wide viewing angle, IPS-mode, VA-mode, OCB-mode

Highly Efficient Photo-triggered Mass Migration in Liquid Crystalline Azobenzene Polymers

Takashi UBUKATA,Nobuyuki ZETTSU and Takahiro SEKI
RIKEN
E-mail: ubukata@riken.jp

Abstract : Since the discovery of photoinduced surface relief formation by mass migration of azobenzene polymer ?lms reported by two groups in America and Canada,a great deal of knowledge has been accumulated on this phenomenon. We have found extremely sensitive systems where full migration is completed within 100 mJ cm . Such systems involve hybrid materials consisting of low-molecular-mass liquid crystal and an azobenzene polymer or liquid crystalline polymers having a ?exible oligo (ethylene oxide) chain. This article gives an overview of the motivation of this research, materials design, features of mass migrating behavior, e?orts for elucidation of mechanisms, and characteristic applications.
Keywords : Azobenzene, E?cient mass migration, Photoinduced surface relief formation, Liquid crystalline polymers, Conveyer action