Most associate liquid crystals with their everyday use in laptop computers, mobile phones, digital cameras, and other electronic devices. However, in contrast to their rodlike (calamitic) counterparts, first described in 1907 by Vorlander, disklike (discotic, columnar) liquid crystals, which were discovered in 1977 by Chandrasekhar et al., offer further applications as a result of their orientation in the columnar mesophase, making them ideal candidates for molecular wires in various optical and electronic devices such as photocopiers, laser printers, photovoltaic cells, light-emitting diodes, field-effect transistors, and holographic data storage. Beginning with an overview of the various mesophases and characterization methods, this Review will focus on the major classes of columnar mesogens rather than presenting a library of columnar liquid crystals. Emphasis will be given to efficient synthetic procedures, and relevant mesomorphic and physical properties. Finally, some applications and perspectives in materials science and molecular electronics will be discussed.

Discotic Liquid Crystals: From Tailor-Made Synthesis to Plastic Electronics

Foreword. Series Editor's Foreword. Preface. 1. Liquid crystal physics.* Introduction.* Thermodynamics and statistic physics.* Orientational order.* Elastic properties of liquid crystals.* Response of liquid crystals to electro-magnetic fields.* Anchoring effects of nematic liquid crystal at surfaces. 2. Propagation of light in anisotropic optical medium.* Electromagnetic wave.* Polarization.* Propagation of light in uniform anisotropic optical media.* Propagation of light in cholesteric liquid crystals. 3. Optical modeling methods.* Jones matrix method.* Mueller matrix method.* Berreman 4x4 method. 4. Effects of Electric field on Liquid Crystals.* Dielectric interaction.* Flexoelectric Effect.* Ferroelectricity in liquid crystals. 5. Freedericksz transition.* Calculus of variation.* The Fredeericksz transition: statics.* The Freedericksz transition: dynamics. 6. Liquid Crystal Materials.* Introduction.* Refractive indices.* Dielectric constants.* Rotational Viscosity.* Elastic constant.* Figure-of-merits.* Refractive index matching between liquid crystals and polymers. 7. Modeling of liquid crystal director configuration.* Electric energy of liquid crystals.* Modeling electric field.* Simulation of liquid crystal director configuration. 8. Transmissive liquid crystal display.* Introduction.* Twisted nematic cells.* In plane switching (IPS) mode.* Vertical alignment (VA) mode.* Multi-domain Vertical Alignment (MVA) Cells.* Optically compensated bend (OCB) cell. 9. Reflective and Trasreflective display.* Introduction.* Reflective liquid crystal displays.* Transflector.* Classification of Transflective LCDs.* Dual-cell-gap Transflective LCDs.* Single-cell-gap Transflective LCDs.* Performance of transflective LCDs. 10. Liquid crystal display matrices, drive schemes and bistable displays.* Segmented displays.* Passive matrix displays and drive scheme.* Active Matrix Displays.* Bistable ferroelectric liquid crystal displays and drive scheme.* Bistable nematic displays.* Bistable cholesteric reflective display. 11. Liquid crystal/polymer composites. * Introduction.* Phase separation.* Scattering properties of liquid crystal/polymer composites.* Polymer dispersed liquid crystals.* Polymer stabilization liquid crystals.* Displays from liquid crystal/polymer composites. 12. Tunable liquid crystal photonic devices. * Introduction.* Laser beam steering.* Variable Optical Attenuators.* Tunable-Focus Lens.* Polarization-Independent LC Devices. Index.

Fundamentals of Liquid Crystal Devices

This tutorial covers an introduction to liquid crystal technology and principles of operation of various modes of liquid crystal displays as well as the development of birefringent optical thin film technologies (e.g., polarizers, compensators) for improving the viewing quality of these displays.

Optics of liquid crystal displays

Recently, 'Liquid crystal display (LCD) vs. organic light-emitting diode (OLED) display: who wins?' has become a topic of heated debate. In this review, we perform a systematic and comparative study of these two flat panel display technologies. First, we review recent advances in LCDs and OLEDs, including material development, device configuration and system integration. Next we analyze and compare their performances by six key display metrics: response time, contrast ratio, color gamut, lifetime, power efficiency, and panel flexibility. In this section, we focus on two key parameters: motion picture response time (MPRT) and ambient contrast ratio (ACR), which dramatically affect image quality in practical application scenarios. MPRT determines the image blur of a moving picture, and ACR governs the perceived image contrast under ambient lighting conditions. It is intriguing that LCD can achieve comparable or even slightly better MPRT and ACR than OLED, although its response time and contrast ratio are generally perceived to be much inferior to those of OLED. Finally, three future trends are highlighted, including high dynamic range, virtual reality/augmented reality and smart displays with versatile functions.

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Liquid crystal display and organic light-emitting diode display: present status and future perspectives

Triphenylene-based discotic liquid crystals, which have already been used commercially in phase compensation films to improve the viewing angle of liquid crystal display devices, also have application potential as one-dimensional charge carrier systems useful in electrical conduction, photoconduction, electroluminescence, photovoltaic solar cells, gas sensing, optical data storage and other devices. Over the past 25 years, more than 500 triphenylene derivatives have been synthesized to explore these possibilities. Cammidge and Bushby reviewed the chemistry and physical properties of about 100 triphenylene-based discotic liquid crystals prepared up to 1995. This review summarizes advances in the chemistry of triphenylene-based discotic liquid crystals since late 1995.

Recent developments in the chemistry of triphenylene-based discotic liquid crystals

The performance of a novel optical compensation film utilizing a negatively birefringent discotic compound was optimized by both simulation and experiment to achieve wide-viewing-angle characteristics of twisted-nematic liquid-crystal displays (TN-LCDs). It was shown that the film remarkably enlarges the viewing angle of TN-LCDs when the discotic compound layer has hybrid molecular orientation which is a similar structure to that of on-state liquid crystals of TN-LCDs.

https://iopscience.iop.org/article/10.1143/JJAP.36.143/pdf

Performance of a Novel Optical Compensation Film Based on Negative Birefringence of Discotic Compound for Wide-Viewing-Angle Twisted-Nematic Liquid-Crystal Displays

PURPOSE:To improve stability against the lapse of time in the photographic sensitive material using cellulose acetate support impregnated with a plasticizer high in molecular weight. CONSTITUTION:This silver halide photographic sensitive material has the support comprising cellulose acetate and one of polyester-ether, polyester-urethane, and polyester, and in this case, at least one of degradation preventive agents, among peroxide decomposers, radical chain reaction inhibitors, metal inactivators, and acid capturers, is to be contained.

Method for preventing degradation of silver halide photographic sensitive material

PURPOSE:To produce the title film excellent in strengths, flame retardance, resistance to bleeding, and storage stability by incorporating a specific plasticizer and a specific degradation preventive into a cellulose ester film contg. triphenyl phosphate as a plasticizer. CONSTITUTION:A cellulose ester film contg. triphenyl phosphate as a plasticizer, another plasticizer of formula I (e.g. a compd. of formula II or III), and at least one degradation preventive selected from the group consisting of a peroxide-decomposing agent (e.g. a compd. of formula IV), a free radical chain transfer inhibitor (e.g. a compd. of formula V), a metal deactivator (e.g. a compd. of formula VI), and an acid acceptor (e.g. a compd. of formula VII) is provided. The plasticizer of formula I prevents bleeding, and the degradation preventive improves the storage stability of the film.

Cellulose ester film, photosensitive silver halide material and treatment method

A cellulose ester film contains a phosphoric ester as a plasticizer. The film further contains an aromatic carboxylic ester represented by the formula [I]. ##STR1## in which n is 3, 4, 5 or 6; R is an alkyl group or an alkenyl group, each of which may have one or more substituent groups; the benzene ring may have one or more substituent groups other than the groups represented by --COOR; and the groups represented by --COOR may be different from each other. A process for preparation of the film is also disclosed.

Cellulose ester film containing phosphoric ester plasticizer and aromatic carboxylic ester and process for preparation of the same

A cellulose ester film contains a phosphoric ester as a plasticizer. The film further contains an aromatic carboxylic ester represented by the formula [I]. in which n is 3, 4, 5 or 6; R is an alkyl group or an alkenyl group, each of which may have one or more substituent groups; the benzene ring may have one or more substituent groups other than the groups represented by -COOR; and the groups represented by -COOR may be different from each other. A process for preparation of the film is also disclosed.

Yukio Shinagawa

Papers

Performance of a Novel Optical Compensation Film Based on Negative Birefringence of Discotic Compound for Wide-Viewing-Angle Twisted-Nematic Liquid-Crystal Displays

Method for preventing degradation of silver halide photographic sensitive material

Cellulose ester film, photosensitive silver halide material and treatment method

Cellulose ester film containing phosphoric ester plasticizer and aromatic carboxylic ester and process for preparation of the same

Cellulose ester film containing phosphoric ester plasticizer and aromatic carboxylic ester