Photoalignment possesses significant advantages in comparison with the usual ''rubbing'' treatment of the substrates of liquid crystal display (LCD) cells as it is a non-contact method with a high resolution. A new technique recently pioneered by the authors of this book, namely the photo-induced diffusion reorientation of azodyes, does not involve any photochemical or structural transformations of the molecules. This results in photoaligning films which are robust and possess good aligning properties making them particularly suitable for the new generation of liquid crystal devices. Photoalignment of Liquid Crystalline Materials covers state-of-the-art techniques and key applications, as well as the authors'' own diffusion model for photoalignment. The book aims to stimulate new research and development in the field of liquid crystalline photoalignment and in so doing, enable the technology to be used in large scale LCD production. Key features: * Provides a full examination of the mechanisms of photoalignment. * Examines the properties of liquid crystals during photoalignment, with particular reference made to the effect on their chemical structure and stability. * Considers the most useful photosensitive materials and preparation procedures suitable for liquid crystalline photoalignment. * Presents several methods for photoalignment of liquid crystals. * Compares various applications of photoalignment technology for in-cell patterned polarizers and phase retarders, transflective and micro displays, security and other liquid crystal devices. Through its interdisciplinary approach, this book is aimed at a wide range of practising electrical engineers, optical engineers, display technologists, materials scientists, physicists and chemists working on the development of liquid crystal devices. It will also appeal to researchers and graduate students taking courses on liquid crystals or display technologies.

Hersteller:
Wiley-VCH GmbH
amartine@wiley-vch.de
Boschstr. 12
DE 69469 Weinheim

Leseprobe

About the Authors 1 Introduction References 2Mechanisms of LC Photoalignment 2.1 Cis-Trans Isomerization 2.2 Pure Reorientation of the Azo-Dye Chromophore Molecules or Azo-Dye Molecular Solvates 2.3 Crosslinking in Cinnamoyl Side-Chain Polymers 2.4 Photodegradation in Polymeric Materials 2.5 Photoinduced Order in Langmuir- Films References 3 LC Surface Interaction in a Photoaligned Cell 3.1 Pretilt Angle Generation in Photoaligning Materials 3.2 Generation of Large Pretilt Angles 3.3 Anchoring Energy in Photoalignment Materials 3.4 Stability of Photoaligning Materials Sensitivity to UV Light 3.5 Comparison of the Characteristics of Photoalignment Layers for Different Mechanisms of LC Photoalignment 3.6 Various Methods for the Experimental Characterization of Photoalignment Layers References 4 Photoalignment of LCs 4.1 Vertical LC Alignment 4.2 Twisted LC Photoalignment 4.3 Photoalignment of Ferroelectric LC 4.4 Optical Rewritable LC Alignment 4.5 Photoalignment with Asymmetric Surface Anchoring 4.6 LC Photoalignment on Plastic Substrates 4.7 Photoalignment on Grating Surface 4.8 Photoalignment of Lyotropic and Discotic LCs 4.9 Other Types of LC Photoalignment References 5 Application of Photoalignment Materials in Optical Elements 5.1 Polarizers 5.2 Retardation Films 5.3 Transflective LCD with Photo-Patterned Polarizers and Phase Retarders 5.4 Security Applications of Photoaligning and Photo-Patterning 5.5 Optical Elements Based an Photoaligning Technology References 6 Novel LCDs Based on Photoalignment 6.1 Bistable Nematic Displays 6.2 Photoaligned Liquid-Crystal-on-Silicon Microdisplays 6.3 Photoaligned Ferroelectric LCDs 6.4 New Optical Rewritable Electronic Paper 6.5 Application of Photoalignment in Photonic LC Devices References 7 US Patents Related to Materials and Processes for Photoalignment of Liquid Crystals, Liquid Crystal Displays, Optical Liquid Crystal Devices and Elements, and Non-Display Applications 7.1 Introductory Remarks 7.2 List of Patents Patent Classification 7.3 Analysis and Comments on the Patents Index