scholarly journals Electro-Optical Switching of Dual-Frequency Nematic Liquid Crystals: Regimes of Thin and Thick Cells

Crystals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 314 ◽  
Author(s):  
Olha Melnyk ◽  
Yuriy Garbovskiy ◽  
Dario Bueno-Baques ◽  
Anatoliy Glushchenko
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Optical Switching ◽  
Nematic Liquid Crystals ◽  
Optical Response ◽  
Thin Layers ◽  
Optical Performance ◽  
Dual Frequency ◽  
Crystal Cells ◽  
Cell Thickness

Conventional display applications of liquid crystals utilize thin layers of mesogenic materials, typically less than 10 µm. However, emerging non-display applications will require thicker, i.e., greater than 100 µm, layers of liquid crystals. Although electro-optical performance of relatively thin liquid crystal cells is well-documented, little is known about the properties of thicker liquid crystal layers. In this paper, the electro-optical response of dual-frequency nematic liquid crystals is studied using a broad range (2–200 µm) of the cell thickness. Two regimes of electro-optical switching of dual-frequency nematics are observed and analyzed.

Optical response from dual-frequency hybrid-aligned nematic liquid crystal cells

2012 ◽  
Vol 57 (5) ◽  
pp. 644-648 ◽  
Author(s):  
E. A. Konshina ◽  
D. A. Vakulin ◽  
N. L. Ivanova ◽  
E. O. Gavrish ◽  
V. N. Vasil’ev
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Optical Response ◽  
Dual Frequency ◽  
Crystal Cells

Photo-Induced Surface Alignment Of Nematic Liquid Crystals On Polyamide-Imide Layers

1995 ◽  
Vol 413 ◽  
Author(s):  
David C. Rich ◽  
Enid K. Sichel ◽  
Peggy Cebet
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Ultraviolet Radiation ◽  
Short Wavelength ◽  
Optical Transmission ◽  
Nematic Liquid Crystals ◽  
Uv Exposure ◽  
Surface Alignment ◽  
Linearly Polarized ◽  
Crystal Cells

ABSTRACTA technique for producing surface-induced liquid crystal nematic alignment is presented. The alignment film is a simple, inexpensive polyamide-imide, which is treated with linearly polarized short wavelength ultraviolet radiation (λ = 254 nm). The alignment performance of UV-aligned layers is shown by optical transmission of the liquid crystal cells to be comparable to that of brushed layers. Strong alignment is produced within minutes of UV exposure and is maintained with long exposures.

Modifying electrooptics of orthoconic antiferroelectric liquid crystal cells by manufacturing procedures

2007 ◽  
Vol 15 (1) ◽  
Author(s):  
A. Spadło ◽  
N. Bennis ◽  
R. Dąbrowski ◽  
X. Quintana ◽  
J. Otón ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Tilt Angle ◽  
Antiferroelectric Liquid Crystals ◽  
Crystal Cells ◽  
Electrooptical Response ◽  
Cell Thickness

AbstractOrthoconic antiferroelectric liquid crystals (AFLCs) having 45° tilt angle have been proposed to overcome the problem of reduced contrast usually exhibited by regular antiferroelectric displays. However, the pitch of the helix induced by chirality is customarily short in existing orthoconic materials, making it difficult to achieve surface stabilized configurations when the material’s pitch is smaller than the cell thickness.In this work, the influence of different manufacturing procedures on the electrooptical behaviour of orthoconic AFLCs is studied. Using the same orthoconic AFLC mixture, aligning surfaces and manufacturing protocol, we have observed two dissimilar responses, true orthoconic behaviour, and orthoconic V-shape response. The electrooptical response depends ultimately on the rubbing strategy adopted in either case.

Frequency-dependent electro-optics of liquid crystal devices utilizing nematics and weakly conducting polymers

2018 ◽  
Vol 7 (4) ◽  
pp. 243-248 ◽  
Author(s):  
Yuriy Garbovskiy ◽  
Anatoliy Glushchenko
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Conducting Polymers ◽  
Nematic Liquid Crystals ◽  
Elementary Model ◽  
Frequency Dependent ◽  
Electric Circuits ◽  
Liquid Crystal Devices ◽  
Weakly Conducting ◽  
Crystal Cells

Abstract Conducting polymer films acting as both electrodes and alignment layers are very promising for the development of flexible and wearable tunable liquid crystal devices. The majority of existing publications report on the electro-optical properties of polymer-dispersed liquid crystals and twisted nematic liquid crystals sandwiched between highly conducting polymers. In contrary, in this paper, electro-optics of nematic liquid crystals placed between rubbed weakly conducting polymers is studied. The combination of weakly conducting polymers and nematics enables a frequency-dependent tuning of the effective threshold voltage of the studied liquid crystal cells. This unusual electro-optics of liquid crystal cells utilizing nematics and weakly conducting polymers can be understood by considering equivalent electric circuits and material parameters of the cell. An elementary model of the observed electro-optical phenomenon is also presented.

New structure induced by elastic anisotropy in cylindrical nematic liquid crystal

2017 ◽  
Vol 13 (2) ◽  
pp. 4705-4717
Author(s):  
Zhang Qian ◽  
Zhou Xuan ◽  
Zhang Zhidong
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Nematic Liquid Crystal ◽  
Elastic Anisotropy ◽  
Nematic Liquid Crystals ◽  
Gennes Theory

Basing on Landau–de Gennes theory, this study investigated the chiral configurations of nematic liquid crystals confined to cylindrical capillaries with homeotropic anchoring on the cylinder walls. When the elastic anisotropy (L2/L1) is large enough, a new structure results from the convergence of two opposite escape directions of the heterochiral twist and escape radial (TER) configurations. The new defect presents when L2/L1≥7 and disappears when L2/L1<7. The new structure possesses a heterochiral hyperbolic defect at the center and two homochiral radial defects on both sides. The two radial defects show different chiralities.

scholarly journals Optical Response Associated with the Orientation and Structure of Liquid Crystals with Respect to Phosphatidylcholine Concentration

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 678
Author(s):  
Yuqi Han ◽  
Yan Jiang ◽  
Wei Guo ◽  
Bing Li ◽  
Lu Zhang ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Reflectance Spectrum ◽  
Optical Response ◽  
The Self ◽  
Cholesteric Liquid Crystals ◽  
Anchoring Effect ◽  
Self Assembling ◽  
Sensitization Effect ◽  
Structure Of Liquid

Based on the anchoring effect due to the self-assembling behavior of the phospholipid molecules at the interface between the liquid crystal and water phases on the orientation of liquid crystals, the optical response associated with the orientation and structure of liquid crystals with respect to the concentration of 1,2-didodecanoyl-sn-glycero-3-phosphocholine solution has been investigated. The optical response owing to changes in the orientation and structure of the mixed cholesteric liquid crystals with respect to the change in the concentration of phosphatidylcholine has been obtained. Moreover, the feasibility of using as-prepared mixed cholesteric liquid crystals to measure the phosphatidylcholine concentration has been verified. A methodology to measure the reflectance spectrum by using mixed cholesteric liquid crystals to sensitize the phosphatidylcholine concentration has been further realized. The sensitization effect of the mixed cholesteric liquid crystals on the measurement of phosphatidylcholine concentration was also verified.

Order parameter of dual-frequency nematic liquid crystals measured over a wide range of thicknesses

2020 ◽  
Vol 47 (9) ◽  
pp. 1338-1344
Author(s):  
Olha Melnyk ◽  
Yuriy Garbovskiy ◽  
Anatoliy Glushchenko
Keyword(s):  
Liquid Crystals ◽  
Order Parameter ◽  
Nematic Liquid Crystals ◽  
Dual Frequency ◽  
Wide Range
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