Ferroelectric Liquid Crystal Displays Research Articles

P‐96: Alignment Optimization on Gen. 4.5 G for High‐framerate Ultra‐high‐resolution Ferroelectric Liquid Crystal Displays

We achieve high‐framerate (< 100 μs) high‐contrast‐ratio ferroelectric liquid crystal displays (FLCD) on Gen 4.5. Innovatively, a new polyimide (PI) that is suitable for ferroelectric liquid crystal (FLC) alignment is synthesized and tested on the production line. It replaces Nylon 6 (N6), which was the barrier to the commercialization of FLCD. Moreover, a new FLC is synthesized to match requirements in mass production. Additionally, various materials were studied to investigate the surface energy and relative performance. It is not only proof of the feasibility on the production line, but also a significant step towards the commercialization of field‐sequential‐color high‐resolution FLCDs.

A new generation of ferroelectric liquid crystals with homogeneous and shock-stable orientation

ABSTRACT This research is focused on ferroelectric liquid crystal compositions with a wide temperature range of the SmC* phase and the design of mechanically stable, fast switching surface-stabilised ferroelectric liquid crystal display with improved electro-optical properties. The work involves the synthesis of high-viscosity achiral compounds and the creation of mixtures based on them that are resistant to mechanical shocks. For this reason, the viscosity of the compositions and the length of achiral molecules were investigated for their impact on mechanical stability of the alignment. For our investigation we synthesised new achiral smectic C compounds containing four or five attached phenyl rings, so called 4,4’-di-substituted quaterphenyls 4,4’-di-substituted-pentaphenyls which have in series-connected benzene rings, but not separated by bridging fragments. We found that the switching of FLCs with such compounds is much faster compared to mixtures containing compounds with the same quaterphenyl or pentaphenyl fragment in chiral molecules. New ferroelectric liquid crystal compositions with optimised parameters have been devised. This work demonstrated that surface-stabilised ferroelectric liquid crystal display could be developed that had switching times less than 10 μs, was stable against mechanical deformations and was independent of alignment material and pre-tilt angle.

Building a Display Field Leader: SKL's Journey

Building a Display Field Leader: SKL's Journey

Super multi-view near-eye display to solve vergence–accommodation conflict

A super multi-view (SMV) technique is applied to near-eye displays to solve the vergence-accommodation conflict that causes visual fatigue. The proposed SMV near-eye display employs a high-speed spatial light modulator (SLM), a two-dimensional (2D) light source array, and an imaging optics for each eye. The imaging optics produces a virtual image of the SLM and real images of the light sources to generate a 2D array of viewpoints. The SMV images are generated using a time-multiplexing technique: the multiple light sources sequentially emit light while the SLM synchronously displays corresponding parallax images. A monocular experimental system was constructed using a ferroelectric liquid crystal display and an LED array. A full-parallax SMV image generation with 21 viewpoints was demonstrated and a comparison of full-parallax and horizontal parallax SMV images provided.

液晶光控取向技术进展

Photoalignment technology is a kind of contactless method of aligning liquid crystal by using polarized light.It possesses many advantages,e.g.,non-contamination,non-electrostatic charges,easy to realize multi-domain aligning even in a tiny fine area,and etc.Thus,it has attracted more and more attentions of the researchers all over the world.The review describes the status of the studies and the recent achievements in the field of photoalignment of liquid crystals,and it briefly illustrates the fundamental working principle of photoalignment technique and mechanisms of liquid crystal photoalignment materials.In particular,we concentrate on a recent approach of the photoinduced reorientation of azo-dyes,and some recent applications of photoalignment technology in aspects of(1)curved and flexible substrates,(2)optical data processing and high spatial resolution optical processing system,(3)liquid crystal optical elements with sophisticated geometric patterned alignment,(4)3D ORW and ferroelectric liquid crystal displays,(5)optical filter and(6)other photoalignment materials,will be introduced.

Poisson–Boltzmann equation and electro-convective instability in ferroelectric liquid crystals: a mean-field approach

Commercialization of ferroelectric liquid crystal displays (FLCDs) suffers from mechanical and electro-convective instabilities. Impurity ions play a pivotal role in the latter case, and therefore we developed a mean-field type model to understand the complex role of space charges, particularly ions in a ferroelectric liquid crystal. Considering an effective ion-chirality relation, we obtained a modified Poisson–Boltzmann equation for ions dissolved into a chiral solvent like the ferroelectric smectic phase. A nonuniform director profile induced by the mean electrostatic potential of the ions is then calculated by solving an Euler–Lagrange equation for a helically twisted smectic state. A combination of effects resulting from molecular chirality and an electrostatically driven twist created by the ions seems to produce this nonuniform fluctuation in the director orientation. Finally, both theoretical and experimental points of view are presented on the prediction of this mean-field model.

Ferroelectric Liquid Crystal Cells for Advanced Applications in Displays and Photonics

Ferroelectric Liquid Crystals (FLC) are discussed for various applications in displays and photonics. We have considered new FLC electrooptic modes based on photoalignment technology: deformed helix ferroelectric (DHF) FLC, Electrically Suppressed Helix (ESH) and Voltage Controllable Diffraction (VCD) FLC Mode. New FLC display and photonics devises such as field sequential color (FSC) FLC displays, switches, grating, Fresnel lens, Circular Dammann (CD) grating are discussed. Certain comparison between ferroelectric and nematic LC devices is provided.

Influence of Electric Field on the Orientation of Ferroelectric Liquid Crystals inside micro capillaries

In the paper we present recent results on investigation of ferroelectric liquid crystals molecules orientation inside photonic crystal fibers, which consist of a set of micro capillaries. We have infiltrated glass micro capillaries with different inner diameters with the experimental ferroelectric liquid crystal mixture W-206K. The orientation of the liquid crystal molecules was controlled by the external electric field applied to the sample. We have obtained promising results about the orientation of the ferroelectric liquid crystal molecules and their behavior under influence of applied external electric field. The presented results may lead to design a new class of fast-switching fiber optic sensors. Full Text: PDF References P. St.J. Russell, "Photonic-Crystal Fibers", J. Lightwave Technol. 24, 4729-4749 (2006). CrossRef T. Larsen, A. Bjarklev, D. Hermann, and J. Broeng, "Optical devices based on liquid crystal photonic bandgap fibres", Opt. Express 11, 2589-2596 (2003). CrossRef T. R. Wolinski, K. Szaniawska, K. Bondarczuk, P. Lesiak, A.W. Domanski, R. Dabrowski, E. Nowinowski-Kruszelnicki, J. Wojcik, "Propagation properties of photonic crystal fibers filled with nematic liquid crystals", Opto-Electronics Rev. 13(2), 177-182 (2005). DirectLink M.W. Haakestad, et al., "Electrically tunable photonic bandgap guidance in a liquid-crystal-filled photonic crystal fiber", IEEE Photon. Technol. Lett. 17, 819–821 (2005). CrossRef Matuszczyk M. "Structures and Properties of Ferroelectric Liquid Crystal Displays", Goteborg, Sweden, Chalmers Reproservice (1996). Q. Guo, E. P. Pozhidaev, A. K. Srivastava, Y. Ma, X. Wang, V. G. Chigrinov, H. S. Kwok, "Deformed Helix Ferroelectric Display with Low Driving Voltage and Fast Response Time", SID Symposium Digest of Technical Papers, Vol. 43 (1), 449-451, (2012). CrossRef E. P. Pozhidaev et al., "High Frequency Low Voltage Shock-Free Ferroelectric Liquid Crystal: A New Electro-Optical Mode with Electrically Suppressed Helix", Proc. of 31-th International Display Research Conference EuroDisplay 2011, Bordeaux-Arcachon, France, September 19-22 (2011). DirectLink Vladimir Chigrinov, Eugene Pozhidaev, Abhishek Srivastava, Guo Qi, Ma Ying, Hoi Sing Kwok, "Fast Ferroelectric Liquid Crystal Modes Based on Photoaligning Technology", SID 2013, Vancouver, Canada, May 2013 Clark, N. A. and S. T. Lagerwall, "Submicrosecond bistable electro-optic switching in liquid crystals", Appl. Phys. Lett. Vol. 36, 899-901(1980). CrossRef S. Mathews, Y. Semenova, G. Rajan, G. Farrell, "Tunable properties of Liquid Crystal filled Photonic Crystal Fibers", Proc. SPIE 7316, 73161E (2009). CrossRef D. Budaszewski, T.R. Woliński, M. A. Geday, J. M. Otón, "Photonic Crystal Fibers infiltrated with Ferroelectric Liquid Crystals", Phot. Lett. Poland 2(3) (2010). CrossRef

Voltage Sensor with wide Frequency Range using Deformed Helix Ferroelectric Liquid Crystal

In this paper we propose a new approach to fiber optic voltage sensors via voltage-controlled Liquid Crystals (LC), which would allow direct measurement of up to 400 kV/m electric fields at multiple points. In addition, the electro-optical behavior of deformed helix ferroelectric (DHF) liquid crystal in reflective mode is described and tested. The electrically controlled reflectance has been measured at sub-kilohertz driving voltage frequency for different polarizations of the incident light. Full Text: PDF References Y.V. Izdebskaya, V.G. Shvedov, A.S. Desyatnikov, W. Krolikowski and Y.S. Kivshar, "Soliton bending and routing induced by interaction with curved surfaces in nematic liquid crystals", Opt. Lett. 35, 1692-1694 (2010). CrossRef Z. Ge, S. Gauza, M. Jiao, H. Xianyu and S.T. Wu, "Electro-optics of polymer-stabilized blue phase liquid crystal displays", Appl. Phys. Lett. 94, 101104 (2009). CrossRef Z. Brodzeli, F. Ladouceur, L. Silvestri, A. Michie, V. Chigrinov, G. Q. Guo, E. P. Pozhidaev and A. D. Kiselev, "Liquid crystal-based hydrophone arrays", APOS (2012). CrossRef T. Tanigawa, Y. Sakakibara, S. Fang, T. Sekikawa and M. Yamashita, "Spatial light modulator of 648 pixels with liquid crystal transparent from ultraviolet to near-infrared and its chirp compensation application", Opt. Lett. 34, 1696-1698 (2009). CrossRef K. H. Yang and T. C. Chieu, "Transport Properties of Ions in Ferroelectric Liquid Crystal Cells", Jpn. J. Appl. Phys. 28, 2240-2246 (1989) CrossRef I.C. Khoo and S.T. Wu, "Optics and Nonlinear Optics of Liquid Crystals", World Scientific, Singapore (1993). V.G. Chigrinov, "Liquid Crystal Devices: Physics and Applications", Artech House, Boston: London, (1999). A.D. Kiselev, E.P. Pozhidaev, V.G. Chigrinov and H.S. Kwok, "Polarization-gratings approach to deformed-helix ferroelectric liquid crystals with subwavelength pitch", Phys. Rev. E 83, 31703 (2011). CrossRef N. A. Clark and S. T. Lagerwall, "Submicrosecond bistable electro-optic switching in liquid crystals", Appl. Phys. Lett. 36, 899-901 (1980). CrossRef L.A. Beresnev, V.G. Chigrinov, D.I. Dergachev, E.P. Pozhidaev, J. Funfshilling and M. Schadt, "Deformed helix ferroelectric liquid crystal display: A new electrooptic mode in ferroelectric chiral smectic C liquid crystals", Liq. Cryst. 5, 1171-1177 (1989). CrossRef Z. Brodzeli, H.K. Bal, V.G. Chigrinov, A. Murauski, and F. Ladouceur, "Electrical energy harvesting device for current/voltage fibre-based sensors", Optical Fibre Technology (ACOFT), 2010 35th Australian Conference on Fibre Technology, 1-2, (2010). DirectLink X. Zhao, F. Boussaid, A. Bermak and V.G. Chigrinov, "High-resolution thin ?guest-host? micropolarizer arrays for visible imaging polarimetry", Opt. Exp. 19, 5565-5573 (2011). CrossRef X.H. Li, A. Murauski, A. Muravsky, P.Z. Xu, H.L. Cheung, and V. Chigrinov, "Grayscale Generation and Stabilization in Ferroelectric Liquid Crystal Display," J. Display Technol. 3, 273-279 (2007). CrossRef E.P. Pozhidaev, S. Torgova, M. Minchenko, C. Yednak, A. Strigazzi and E. Miraldi, "Phase modulation and ellipticity of the light transmitted through a smectic C* layer with short helix pitch", Liq. Cryst. 37, 1067-1081, (2010). CrossRef E.P. Pozhidaev and V.G. Chigrinov, "Bistable and multistable states in ferroelectric liquid crystals", Crystallography Reports. 51, 1030-1040 (2006). CrossRef Q. Guo, F. Fan, T. Du, and V.G. Chigrinov, "Electrooptic Response of FLC: Effect of Alignment Materials", SID'11 Conference, P-144, Los Angeles, USA, May, (2011). CrossRef G. Hegde, P. Xu, E.P. Pozhidaev, V.G. Chigrinov, and H.S. Kwok, "Electrically controlled birefringence colours in deformed helix ferroelectric liquid crystals", Liq. Cryst. 35, 1137-1144 (2008). CrossRef

Synthesis of Small Silicate Spacers for Ferroelectric Liquid Crystal Displays

In the presence of the aqueous solution of ammonia, tetraethyl orthosilicate (TEOS) was hydrolyzed in the mixture of ethyl alcohol and water with the results of silica spacers. The spacer morphology and size distribution of the synthesized silica spacers were characterized with scanning electron microcopy and laser light scattering spectroscopy, respectively. Our results demonstrated that the synthesized silica spacers were monodispersed and were in perfect spherical shape with their sizes of about 0.7 m in diameter. The correlation between the spacer sizes and the amount of ammonia catalyst was examined, and the spacer sizes of the silica spacers strongly depended on the temperature of chemical reaction and the amount of catalyst. The diameter of silica spacers could be well controlled by controlling the amount of ammonia catalyst, and uniformly distributed silica spacers were produced. Behavior of the miscibility of the silica spacers with a nematic liquid crystal was examined.

Inherent Continuous, Hysteretic Free and Memorized Gray Scale of FLC Display Cells Based on Bi- and Multistability Effects

Ferroelectric liquid crystal (FLC) mixtures with high spontaneous polarization (Ps > 50 nC/cm 2 ) possessing ferroelectric domains [1] exhibit a multistability effect which has been known for more than 10 years [2, 3]. Any light transmission level can be memorized in the effect after the driving voltage is switched off. The multistability effect is responsible for three new electrooptical modes with continuous, memorized and reversible gray scale. Depending on the asymmetry in boundary conditions and crystallooptical parameters of the cell, these modes differ among themselves under the shape of the gray scale curve that can be either S (double or single) or V-shaped. Origin of the phenomenon is under consideration here.

P‐189: Fast Response Transflective Display Using a Tight Pitch Ferroelectric Liquid Crystal in a Single Gap Configuration

AbstractWe report on a fast response transflective display using a vertically aligned tight pitch ferroelectric liquid crystal (FLC) in a single gap configuration. The optical path difference between transmissive and reflective regions is compensated by adopting in‐plane electrodes on two substrates and on one substrate, respectively. In our transflective FLC display, several unique features such as uniform alignment, fast response, and gray scale capability are demonstrated.

Comparative Analysis of Time and Spatially Multiplexed Diffractive Optical Elements in a Ferroelectric Liquid Crystal Display

We present a very simple method of generating time-multiplexed optical diffractive elements. We use a commercially available ferroelectric liquid crystal device originally designed to visualize colour images by sequentially displaying the three red, green, and blue (RGB) colour channels. We substitute the original light emitting diode (LED) light source by monochromatic illumination. Then we generate a three time-multiplexed diffractive element simply by addressing a colour RGB image where each colour component corresponds to a different diffractive screen. We carry out computer simulations in order to compare this simple time multiplexing technique with various spatial multiplexing techniques proposed in the literature. We numerically evaluate the different methods in terms of light efficiency, noise level and the quality of the hologram reconstruction. We provide experimental results that verify the simulations and show the advantage of using the time multiplexing technique.

X-ray Scattering Studies of Phase-Separated Composite Organic Film Cells

The authors report X-ray scattering experiments on phase-separated composite organic film (PSCOF) structures mixed with ferroelectric liquid crystals (FLCs). We discuss the effect of the local layer structure in a PSCOF cell on the ratio of the concentration between prepolymer and liquid crystals. The ratio of optimized concentration in terms of optical characteristics for a PSCOF liquid crystal display are 30 wt % for prepolymer (NOA65) and 70 wt % for FLCs (Felix). We found that the layer structure in a ferroelectric liquid crystal cell made of 30 wt % NOA65 and 70 wt % Felix is a tilted-bookshelf layer structure. The angles 15 and 17° are the tilted-bookshelf angles at 65 and 58 °C, respectively. These layer tilt angles are almost same as the molecular tilt angles of ferroelectric liquid crystals in the Sm C* phase. We understand that this result comes from compensating for layer buckling. We consider that the PSCOF-mode local layer structure is an excellent solution to the problem of zig-zag defects and mechanical shock for application in future televisions and plastic ferroelectric liquid crystal displays (FLCDs).

Molecular Alignment in Ferroelectric Liquid Crystal Display Having Microscopically Patterned Electrodes

Ferroelectric liquid crystals (FLCs) are one of the promising materials for next-generation liquid crystal displays (LCDs) because of fast response, microsizing of pixel and so on. Since the molecular alignment structure of FLC is strongly affected by the surface roughness of substrate, it is important to investigate the influence of the microscopically patterned electrodes on the alignment of FLC molecules. In this study, we have researched the influence of the unevenness of the electrodes on the surface of the polyimide alignment film and the alignment structure of FLC, and then tried to obtain a defect-free uniform alignment even in FLCD having microscopically patterned electrodes. As a result, it was obvious that the way of wetting of the polyimide solution is largely different even in the small difference of the surface unevenness in the patterned electrodes. A uniform alignment of FLC molecules was obtained by using the combination of a flat surface of polyimide film and a relatively even surface of the glass substrate with microscopically patterned electrodes.

Grayscale Generation and Stabilization in Ferroelectric Liquid Crystal Display

Intrinsic grayscale generation and stabilization in ferroelectric liquid crystal display (FLCD) have been proposed and investigated. Study of the FLC samples shows that the switching process takes place through the formation and evolutions of domains formation. Dynamic current and electrooptical response in FLC testing cell are discussed as a criterion of memorized grayscale generation for FLC display. Grayscale stability for different crosstalk effects under a passive multiplex driving scheme is demonstrated. Passive 160 160 multiplex addressing photo-aligned 5- reflective FLCD with a high contrast and four memorized grayscale levels is developed.

Reduction in Driving Voltage of Vertically Aligned Ferroelectric Liquid Crystal Display by Diminishing Anchoring Force of Alignment Layer

We investigated the electrooptical properties of vertically aligned ferroelectric liquid crystal (VAFLC) cells by applying a transverse electric field induced by interdigital electrodes. Compared with a surface-stabilized FLC (SSFLC) cell, a VAFLC cell has an analog-grey scale capability requiring a high driving voltage. In this study, we propose two alignment methods, the single- and double-sided rubbed methods, to reduce the driving voltage of the VAFLC cell. The dynamic response time is below 1 ms in our methods. A single-sided polyimide aligned method can achieve a contrast ratio of 520 at an applied voltage of 50 V.

τ− V min addressing mode and an improved equivalent circuit model for ferroelectric liquid crystal displays

The authors describe an improved model for modelling the electro-optical response of a ferroelectric liquid crystal display and discuss its applicability. The model includes the direct coupling of applied electric fields to dielectric permittivity, an effect not accounted for in previous equivalent circuits. Compared with previous models, the new model has more capability in optical response prediction and device setup optimisation when the dielectric biaxiality of ferroelectric liquid crystals is of a relatively high value. In the improved model, different trends of switching time are observed as drive voltage rises in cases of positive anisotropy and negative anisotropy. The bend in tau-V min mode, that is, the minimum pulse area for switching directors, is measured and the mechanism of optical contrast enhancement and switching process complemented by high-frequency ac pulses is clearly explained. Results obtained from the improved model compare favourably with that obtained from numerical models and from testing of a real cell

Passively addressed FLC display possessing an inherent gray scale and memory

Abstract— A passively addressed 64 × 64 ferroelectric liquid‐crystal display (FLCD) has been developed. The display matrix has a 33 × 33 mm2 aperture, and the FLC layer thickness is 5.2 ± 0.2 μm. The display device operates with a frame frequency of 30 Hz (at Vrow = ±18 V, Vcol = ±9 V, T = 23°C), generating a continuous gray scale which can be memorized for more than 10 days after the driving voltage is switched off. A new approach for multiplex electronic addressing of the FLCD gray scale is proposed. The conditions of the hysteresis‐free gray‐scale generation for multiplex addressing and the gray‐scale memorization after the voltage is switched off, as well as the time steadiness of memorized images, are considered.

Photoaligned Ferroelectric Liquid Crystal Passive Matrix Display with Memorized Gray Scale

A new concept of a passive matrix ferroelectric liquid crystal display (FLCD) with a memorized gray scale is proposed. The physical origin of the gray scale in ferroelectric liquid crystal displays is considered. The criterion of reliable bistability is derived depending on the FLC hysteretic behavior in an electric field. The frequency and temperature dependences of the FLC hysteretic loop are discussed. A new approach for multiplex electronic addressing of the FLCD gray scale is given. A passively addressed 64×64 FLCD based on the photoalignment technique is developed. New applications of passively addressed FLCDs with a memorized gray scale are envisaged.