The New Electro-optic Effects for Chiral Nematic Liquid Crystals
Author: J. Chen
Publisher:
Published: 2009
Total Pages:
ISBN-13:
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Author: J. Chen
Publisher:
Published: 2009
Total Pages:
ISBN-13:
DOWNLOAD EBOOKAuthor: Jing Chen
Publisher:
Published: 2009
Total Pages:
ISBN-13:
DOWNLOAD EBOOKAuthor: Per Rudquist
Publisher:
Published: 1993
Total Pages: 120
ISBN-13:
DOWNLOAD EBOOKAuthor: L.M. Blinov
Publisher: Springer Science & Business Media
Published: 2012-12-06
Total Pages: 477
ISBN-13: 1461226929
DOWNLOAD EBOOKElectrooptic effects provide the basis for much liquid-crystal display technology. This book, by two of the leaders in liquid-crystal research in Russia, presents a complete and accessible treatment of virtually all known phenomena occurring in liquid crystals under the influence of electric fields.
Author: Bronje Musgrave
Publisher:
Published: 2000
Total Pages: 233
ISBN-13:
DOWNLOAD EBOOKAuthor: Vinay Joshi
Publisher:
Published: 2018
Total Pages: 213
ISBN-13:
DOWNLOAD EBOOKThe recent discovery of high-temperature mesophase, also known as the twist-bend nematic phase in liquid crystal dimers (or bimesogens) has triggered interest due to its unique structure-property relationship. Bimesogens consisting of two mesogenic units separated by odd-membered flexible alkyl chain possess a bent molecular formation which results in a low bend elastic constant (K3) and also facilitates flexoelectro-optic response that can be exploited for innovative technological development in the field of displays and other electro-optic devices. In this dissertation, the dynamics of bimesogen-doped chiral nematic liquid crystal (N*LC) during is studied to understand the influence of low K3 as the rod-like LCs undergo Freedericksz transition from bend to splay. The tilt degeneracy in LCs occurring during bend-to-splay deformation of N*LCs switch, the effect is manifested as the optical bounce in the dynamic electro-optic response. The bimesogens, having short flexible spacers tend to enhance the optical bounce in N*LCs and results in a long response time for homeotropic-twist transition. To enable a fast response time, N*LCs are polymer stabilized with surface-localized protrusions that lowers the backflow during electro-optic response and thereby suppresses the optical bounce by 78% and reduces the response time by >90%. In the second part, to further explore the omnipresent property of bimesogenic nematic materials, a fast flexoelectro-optic response in bimesogen-doped N*LCs with an out-of-plane swing in vertical standing helix was proposed and systematic studied with a series of bimesogens reveal the correlation between the flexoelectrically-driven swinging amplitude of the helices in N*LCs and the flexible spacer length in the bimesogens. The giant flexoelectrically-switched tilt leads to a helix-tilt angle up to 53℗ʻ. The experimentally measured maximum flexoelastic ratio (e/K) of polymer stabilized N*LCs was 2.758 CN-1m-1. Moreover, the LC device exhibits sub-millisecond response time (0.43 ms), low electric-field ramping hysteresis and high optical contrast (500:1) between field-on and field-off state. These observations are of considerable scientific and technological importance and will open up new forays into field-sequential-color devices that provide an energy-efficient solution to current color-filter-based display technology.In the third part, a wide spectra color-reflective device based on polymer-sustained conical helix (PSCH) is explored and demonstrated. Apart from the selective reflection of light, the device also demonstrates light-scattering focal conic texture in off-state and transparent homeotropic state at a high electric field. The memory effect produced by a granular polymer network not only mirrors the conical helix but also facilitates a long-range pitch modulation in a cholesteric during the increasing and decreasing of the electric field. A wide color gamut with high spectral purity and uniform structural colors across the entire electrode area is achieved with the PSCH.The last part of dissertation describes the development of a multiplanar volumetric 3D device with time-multiplexed series of 2-D images using a sequential switching stack of reverse-mode polymer stabilized cholesteric texture (R-PSCT) films and digitally synchronized with 2-D image projection. R-PSCT films tend to lose optical clarity in off-state after few switching cycles due to deformation in the polymer network. To investigate the electro-mechanical characteristics of R-PSCT, a systematic study is performed by varying the concentrations of two different reactive mesogens: RM6 and RM257. The optimum composition of reactive monomer for R-PSCT was found to be 80% RM6+20% RM6 that yields the optical contrast of ~ 7, turn-on time 1.1 ms, turn-off time 1.8 ms and wide viewing angle with a cone of 120℗ʻ.
Author: Heinz Kitzerow
Publisher: Springer Science & Business Media
Published: 2006-04-28
Total Pages: 513
ISBN-13: 0387216421
DOWNLOAD EBOOKDescribes the main aspects of chirality in liquid crystals, and points out some of the open questions of current research. The chapters review the highlights of the important topics and questions.
Author: Stephen D. Jacobs
Publisher:
Published: 1992
Total Pages: 736
ISBN-13:
DOWNLOAD EBOOKAuthor: Lev Mikhaĭlovich Blinov
Publisher: John Wiley & Sons
Published: 1983
Total Pages: 376
ISBN-13:
DOWNLOAD EBOOKAuthor: Agnes Buka
Publisher: World Scientific
Published: 2013
Total Pages: 299
ISBN-13: 1848167997
DOWNLOAD EBOOKThe book intends to give a state-of-the-art overview of flexoelectricity, a linear physical coupling between mechanical (orientational) deformations and electric polarization, which is specific to systems with orientational order, such as liquid crystals. Chapters written by experts in the field shed light on theoretical as well as experimental aspects of research carried out since the discovery of flexoelectricity. Besides a common macroscopic (continuum) description the microscopic theory of flexoelectricity is also addressed. Electro-optic effects due to or modified by flexoelectricity as well as various (direct and indirect) measurement methods are discussed. Special emphasis is given to the role of flexoelectricity in pattern-forming instabilities. While the main focus of the book lies in flexoelectricity in nematic liquid crystals, peculiarities of other mesophases (bent-core systems, cholesterics, and smectics) are also reviewed. Flexoelectricity has relevance to biological (living) systems and can also offer possibilities for technical applications. The basics of these two interdisciplinary fields are also summarized.