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Liquid crystals have numerous applications in various fields ranging from drug delivery, gene therapy in biosciences to electronic display and sensors in the field of opt-electronics and material science. In recent years, the properties of liquid crystals have been tailored by truncating the terminal atom(s) or group of atoms and/or by doping different types of nanomaterials; such as nanodots, nanorods, nanotubes, nanoplatelets, etc. Controlled assembly of nanoparticles in liquid crystal media can provide an alternative method to tailor new and desired opto-electronic properties in uniquely arranged quantum dots. This self-assembly of nanoparticles produces new hybrid (composite) materials having large number of applications. Here, we review different applications of nanoparticles and liquid crystal systems and highlight different approaches for achieving the hierarchical arrangement of nanoparticles in liquid crystal media. Here, phenomena like quantum dot self-assembly, formation of hollow microstructures, memory effect, and formation of microcapsules, etc. in presence of liquid crystal media are revisited and discussed critically. Band-gap-tailoring has emerged as a major thrust area because of numerous applications in making opto-electronic devices. Band-gap of liquid crystals can be also be tailored either by doping (metal) atoms or by nucleating their nano-clusters after removing their terminal groups. This phenomenon creates a lot of attraction among scientists. Hierarchical arrangement of nano-dots in liquid crystal media has gained a lot of interest, as they can possess special functional properties; many of which are known whereas many others need to be discovered. Hierarchical arrangement of nano-clusters can be obtained either by doping atoms into liquid crystals followed by a nucleation process or by forming molecular architectures by weak coupling between quantum dots because of van der Waal forces. Functional properties such as magnetic, physiochemical, and opto-electronic properties of the hybrid systems are different from their constituent parts, and thus the hybrid systems can find a vital role in the field of nanoscience and nanotechnology. Because of the aforesaid reasons, it has gained much attention in the last few decades. [ABSTRACT FROM AUTHOR]

Effortless separation without damage to the substrates is highly advantageous for the recovery and recycling of expensive electronic components in display devices. In this study, we present an approach for separating transparent adhesive films from substrates using phase-change core-shell nanocapsules. The nanocapsules are prepared from poly(methyl methacrylate) (PMMA) nanoparticles via the encapsulation of methylcyclohexane (MCH). The evaporated MCHs facilitated the detachment of adhesive films through micro-bubble generation after thermal treatment, leading to the effortless separation of the adhesive layer. The newly fabricated adhesive film with phase-change nanocapsules resulted in high transmittance, with an excellent debonding efficiency after thermal treatment. [ABSTRACT FROM AUTHOR]

In this study, we have studied a method to evaluate the image quality of a convex display and developed a film that can eliminate the ghost image which is pointed out as the biggest problem of image quality deterioration. The brightness uniformity of the screen varies greatly depending on the measurement position due to the shape of the curved surface display, and the unwanted ghost image is generated by the cover window attached to the curved display. The ghost image can be eliminated considerably by attaching a film having a groove structure, and it is possible to develop an efficient shape on film by controlling the size of the groove structure. As a result, the brightness of the ghost image could be reduced from 39.1 cd/m2 to 4.8 cd/m2, and four splitted images with sharp edges could be displayed as a small blur at the edge, so it possible to improve readability and sharpness of convex display. [ABSTRACT FROM AUTHOR]

4-methyl-7-(10-(pyren-1-yl)anthracen-9-yl)-2H-chromen-2-one (PAC), 7,7'-(anthracene-9,10-diyl)bis(4- methyl-2H-chromen-2-one) (CAC), 7-Ant-hracen-9-yl-4-methyl-chromen-2-one (AC), and 7-(naphthalen-1-yl)-2H-chromen-2-one (NC) were synthesized through Suzuki aryl-aryl coupling reaction. Optical and electroluminescence (EL) properties were evaluated by UV-visible absorption, photoluminescence (PL) spectra, and EL devices. Synthesized compounds were used as an emitting layer (EML) in non-doped device with the following structures: ITO/2-TNATA (60 nm)/NPB (15 nm)/synthesized compounds (35 nm)/Alq3(20 nm)/LiF (1 nm)/Al (200 nm). Non-doped devices showed luminance efficiency (L.E.) of 1.38, 1.03, 1.12, and 0.39 cd/A at a current density of 10 mA/cm2. [ABSTRACT FROM AUTHOR]

We successfully developed a 3D liquid crystal display (LCD) modeling program and applied the program to modeling the single-domain vertical alignment (VA) and intrinsic fringe field controlled multi-domain vertical alignment (IFF MVA) LCDs. Our study showed that proper and stable IFF MVA operation was obtained in the microdisplay geometry but not in the direct-view geometry, whereas regular VA operation was obtained in the direct-view geometry but not in the microdisplay geometry. [ABSTRACT FROM PUBLISHER]

The effect of various metal-oxide nanoparticles embedded in the alignment layer of a liquid crystal (LC) display is experimentally investigated. The study mainly focuses on the electro-optical properties of a twisted-nematic LC display. It is confirmed that a certain type of nanoparticles contribute to the enhancement of contrast ratio. In addition, it is observed that for almost all types of nanoparticles used in the present study, the statistical error of electro-optical properties of LC test cells reduces as compared to that of cells without nanoparticles, indicating the improvement of LC molecular alignment. For a further clarification, AFM study and other related measurements are performed. [ABSTRACT FROM AUTHOR]

Periodical groove structure was formed on the substrate surface by copying the structure on the grating film on the market to the photo curable resin coated on the substrate surface. And then, the substrate surface with groove structure was rubbed along the direction perpendicular to the groove. Alignment of LC on such substrate surface was experimentally investigated. And the occurring of pre-tilt was confirmed. In a cell constructed using such substrate and, for the other side, the substrate treated by a vertical alignment material, distinctive domains with different orientation direction were observed. This suggests us that the bistable alignment property can be adapted on the substrate surfaces by the method above mentioned. [ABSTRACT FROM AUTHOR]

Here in this investigation, the molecules exhibiting photoisomerization in solutions is also photostable is observed. On the other hand molecules not showing photoisomerization behavior in solutions is not shown such kind of stability. Surprising behavior in which after writing laser is turned off, there is going to be increase in phase retardation (or order parameter) which is under deep consideration. Detail investigation is in progress to reveal the behavior of chemical structures when light is shined on them. Proposed investigation is crucial for selecting suitable azo dyes for photoalignment studies and also for many commercial applications which depends on many factors like stability, order parameter etc. [ABSTRACT FROM AUTHOR]

The methods of pixel arrangement for autostereoscopic liquid crystal displays based on conventional vertical parallax barriers are summarized. A novel method of pixel arrangement for autostereoscopic liquid crystal displays based on step parallax barriers is proposed. The pixel arrangements are given for different inclined angles of parallax barriers and different column numbers of images. A demo of the autostereoscopic liquid crystal display using the new method of pixel arrangement presents very good stereo images. The results help to solve the process, storage and transmission of stereo images of autostereoscopic liquid crystal displays based on parallax barriers. [ABSTRACT FROM AUTHOR]

In this study, we use the commercial simulation software, DIMOS2.0, to study improvement of viewing angle performance. Based on concepts of optical phase compensation, optimized conditions of composite uniaxial compensation films are achieved in optically compensated bend (OCB) liquid crystal displays (LCDs). In conditions of D65 illumination for compensated cells, it shows that viewing angles with contrast ratio over 10 are in the ranges of horizontal 100° and perpendicular 130°. No gray scale inversion occurs within polar angle of 70° at horizontal direction. According to definition of CIE 1931, color coordinate of white point in non-compensated and compensated simulated cells are (0.29634, 0.32592) and (0.27143, 0.29306) at on-axis viewing direction, respectively. Contrast ratio is over 3000 at on-axis viewing direction. [ABSTRACT FROM AUTHOR]

In the bistable chiral splay nematic (BCSN) mode, the splay and π twist states are used for the two stable states. The transition between the memory states accompanies the motion of the disclination line, due to the topologically inequivalent from each other. The switching time is consistently coupled with the propagation velocity of the disclination line, which strongly depends on the amplitude of the applied voltage. In this paper, we demonstrate the gray scale of BCSN liquid crystal display (LCD) by the control of the domain density of the splay and twist states during the transition process. [ABSTRACT FROM AUTHOR]

An active-matrix polymer network liquid crystal display (AMPNLCD) of 1.79'' QCIF(176 × 144) was fabricated. The operating mode of normally black was reversed to normally white by using crossed polarizers. The contrast ratio, as a result, was drastically increased, which was comparable to a conventional liquid crystal display. The response time at a typical driving voltage, 2.8 V, was also fast enough to play still image smooth. The electro-optic properties of AMPNLCD with crossed polarizers were evaluated and discussed. [ABSTRACT FROM AUTHOR]

We demonstrate the stability-enhanced novel flexible liquid crystal display (LCD) mode by using the micro-structure of rigid columnar spacer array and a micro-contact printing (µCP) assembling method. Specially designed multi-column structure induces self-collected structure of adhesion material which resulted in the good adhesion properties of device to an external deformation as well as enhanced mechanical stability of electro-optic characteristics for flexible display application. Moreover, suggested method can easily inherit most advantages of conventional LCD technology such as low driving scheme, established process and LC mode selection freedom within a simple fabrication procedure. This novel technique can be highly applicable for realizing practical flexible display with enhanced mechanical stability and high performance. [ABSTRACT FROM AUTHOR]

Microcapsules of durability and deformability along with excellent transparency, which was designed for the application of electrophoretic display system, have been synthesized. Microcapsules were synthesized by two-step condensation polymerization using melamine-formaldehyde (MF) resin. In this work, durability and flexibility of MF microcapsules activated by acid catalyst were characterized by compression test accompanied by visual inspection. Microcapsules of MF-AA (using acetic acid as acid catalyst) were rapidly ruptured at force 0.8 mN, while those of MF-MA (using maleic anhydride as acid catalyst) were highly deformed to show a permanent failure at 3.8 mN. Furthermore MF-MA microcapsule showed extremely higher deformation ratio than MF-AA, implying that the maleic anhydride activated system would be much more durable and flexible than the MF system employing AA. [ABSTRACT FROM AUTHOR]

The luminous efficiency of the organic light-emitting devices (OLEDs) with a mixed layer in a hole transport layer (HTL) and an emitting layer (EML) was highest among the fabricated OLEDs, and the luminous efficiency of the OLEDs with a mixed layer at 10 mA/cm2 was 6.5 cd/A. The Commission Internationale de l'Eclairage (CIE) chromaticity coordinates of the OLEDs fabricated utilizing a mixed layer became stabilized, and the CIE chromaticity coordinates of the OLEDs at 15 V was (0.457, 0.510), indicative of a deep yellow color. The efficiency enhancement and the color stabilization of the OLEDs with a mixed layer were attributed to the exciplex emission process. [ABSTRACT FROM AUTHOR]

The bending angle effect on a multi-domain in-plane switching liquid crystal display (MD IPS LCD) using the chevron-shaped electrodes is investigated through a three-dimensional simulation. We find that when the bending angle of the electrodes increases from 10° to 40°, the threshold voltage is lowered from 1.25 V rms to 0.75 V rms . With the optimized uniaxial compensation films, the viewing angle of the film-compensated MD IPS LCD is widened to ±80° viewing cone while keeping a 100:1 contrast ratio. These outstanding performances are expected to make impact to the flat panel display industry. [ABSTRACT FROM AUTHOR]

Emissive displays use additive color synthesis provided by two dimensional Red Green Blue pixels arrays; reflective displays would use the subtractive color synthesis from primary Cyan Magenta Yellow colors: several attempts show that photographic like structures using 3 active superposed color layers constitutes a very challenging objective. Beside the transflective mode compromise, most current attempts concern black and white or bicolor reflective displays, as well as reflective micro displays for image projectors. After reviewing these technologies, we consider some new approaches to reflective color displays, including the direct color synthesis using physical colors generation such as light dichroic reflection, diffraction and scattering. [ABSTRACT FROM AUTHOR]

Most twisted nematic liquid crystal displays (TN-LCD) uses liquid crystal mixtures with a positive dielectric anisotropy. In contrast, the recently introduced vertically aligned liquid crystal display (VA-LCD), which offers superior picture quality with a wide viewing angle, high contrast, and video-compatible switching times, is based on a liquid crystal mixture with negative dielectric anisotropy. We introduce here the synthetic route and physical and electro-optical properties of the liquid crystalline compounds with an ester group as linkage subsistent and with an alkyl chain as lateral subsistent. Also, we present physical and electro-optical properties of their mixture, and the LC-series for VA-LCD. Synthetic compounds exhibit broad range nematic phases up to 60 K degree and large negative dielectric anisotropies. And the viscosity of the LC-series is low in comparison with that of homologues with a lateral isothiocyanate group. The threshold voltage (Vth) was lower than that of a conventional mixture, enough so for it to be operated at a driving voltage. And the rising time of some LC-series improved to be faster than conventional LC mixtures. Our novel LC compounds are suitable materials for the improvement of the dielectric anisotropy of vertically aligned liquid crystal mixtures. [ABSTRACT FROM AUTHOR]

Continuing our interest in the ferroelectric liquid crystalline materials for display applications we have synthesized new chiral aryl esters of 4-alkyl-3-methylbiphenyl-4′-carboxylic acids. Using different percentage of these compounds and aryl esters of 4-alkyl-3-chlorobiphenyl-4′-carboxylic acids we have designed the FLC mixtures with values of spontaneous polarization from 30 to 170 nC/cm 2 , tilt angle from 20° to 40°, helical pitch (> 0.2 μm) and the constant value of the optical anisotropy (∼⃒ 0.35). [ABSTRACT FROM AUTHOR]

The cholesteric filters can improve the efficiency of light use when it is applied to a reflective mode. They reflect circularly polarized incident light of the same handedness as the cholesteric helix and transmit the one having the opposite handedness. The transmission bandwidth depends on the helical pitch. In order to widen the bandwidth, we synthesized new cholesteric liquid crystal molecules containing the active reaction moeity to UV light and investigated the various UV treatment methods to broaden the bandwidth of the cholesteric filters. There was appears that the band broadened about 200  nm by using the photo-mask. It is caused of a factor as a consequence of UV-curing when the cholesteric pitch changes locally by using the mask. [ABSTRACT FROM AUTHOR]

The in-plane switching(IPS)mode liquid crystal display(LCD)panels with different pretilt angles and alignment directions are prepared, and their electro-optical properties and viewing angle characteristics are examined. The examination shows that parallel alignment with a pretilt angle of about 3∗brings about a panel with very wide viewing angle characteristics and little color shift in relation to that viewing angle. The pretilt angle of 3∗can be achieved by conventional alignment film for Twisted Nematic mode LCD, and higher productivity of IPS-mode LCD panels in consequently expected. [ABSTRACT FROM AUTHOR]

In this work, synthesis of a photo-crosslinkable polyimide (polyimide (PI)-chalcone(Chal)-biphenyl (BP)) based polymer and electro-optical (EO) performances of photoaligned twisted nematic (TN) - liquid crystal displays (LCDs) using the two kinds of the photodimerization method with obliquely polarized UV exposure on a photopolymer were investigated. High pretilt angle of the NLC was measured by polarized UV exposure using the conventional photodimerization method on the PI-Chal-BP surface for 3  min. The high pretilt angle of the NLC generated in NLC is attributable to the biphenyl moieties and the photodimerized chalcone group of the photopolymer. The NLC pretilt angle using the conventional photodimerization method was higher than that of a in-situ photodimerization method. Additionally, good voltage-transmittance (V-T) curves and response time for the photoaligned TN-LCD were observed by UV exposure on the PI-Chal-BP surface for 3  min using conventional photodimerization method. However, EO characteristics of the photoaligned TN-LCD on the PI-Chal-BP surface for 1  min using the in-situ photodimerization method were achieved. [ABSTRACT FROM AUTHOR]

With conventional nematic liquid crystal displays there is only one orientation of the material that is stable without an applied field. In order to maintain an image the pixels have to be continually refreshed, placing an upper limit on the pixel count. Overcoming this requires having some memory within each pixel. To avoid putting an expensive transistor within every pixel one can design the display to be inherently bistable. Here we describe how micron-scale posts on a substrate can stabilize multiple orientations. By engineering the posts we have demonstrated a bistable display with long term memory. [ABSTRACT FROM AUTHOR]

UV-transparent nematic liquid crystals synthesised specifically for use as components of nematic mixtures for the Photoluminescent Liquid Crystal Display (PL-LCD) are reported. These polar and apolar nematic liquid crystals do not possess conjugated phenyl rings or cyano-groups. Where two phenyl rings are present, they are separated by a non-conjugated linking group, so that they do not absorb in the visible or the near ultra-violet. Polar and apolar nematics have been combined to generate UV-transparent nematic mixtures of positive dielectric anisotropy for use in TN-PL-LCDs and STN-PL-LCDs transmitting monochromatic UV light at 365 or 390 nm. [ABSTRACT FROM AUTHOR]

Supertwisted nematic (STN) liquid crystal displays remain a leading technology for mobile communications applications, personal digital assistants (PDA) and personal convergence devices. Higher demands on display information content place ever increasing demands on the physical parameters of the liquid crystal mixture. To satisfy current and future display requirements, it is necessary to develop mixtures showing: Fast response times achieved by rotational viscosity reduction and birefringence increase. Small temperature dependence of the operating voltage (dV=dT), especially at low temperatures. Small frequency dependence of the operating voltage (dV=df), necessary for multi-level greyscale operation. Improved steepness (V90=V10) of the electro-optical curve to enable higher duty multiplexing of the display. In order to fulfil these requirements, liquid crystal mixtures with improved physical properties were developed. Examples of these mixtures are presented. [ABSTRACT FROM AUTHOR]

We examined the conditions that produce no grayscale inversion over a wide-viewing-angle. We also examined the optimum conditions for a retardation film that compensates for the retardation of all LC cells in the dark state. Using these conditions, we realized a wide-viewing-angle, high-contrast LCD with a simple structure and high brightness. [ABSTRACT FROM AUTHOR]

A synthesis of new photoalignment material PNC, poly norbornene-2,3-dicarboxylic acid cholesteryl ester, and the electro-optical (EO) performances of the photoaligned vertical-alignment (VA)-liquid crystal display (LCD) on the PNC surface were studied. EO characteristics of the photoaligned VA-LCD on the PNC layer using a UV filter-less method proved more effective that of the UV filter method for short UV exposure time. The response time of the photoaligned VA-LCD on the PNC layer by the photoalignment method without UV filter is almost the same as the rubbing aligned VA cell. [ABSTRACT FROM AUTHOR]

We propose in-cell LCD films with a function of compensation films and alignment layers. The processes used to create these functions exclude mechanical contact with the films. There is proposed approach decoupling retardation and liquid crystal alignment. This approach is employed to realize different combinations of retardation and alignment properties. [ABSTRACT FROM AUTHOR]

In this work the mathematical model of a light propagation through the system of layers with dichroic properties are presented. This model makes it possible to obtain the spectral characteristics of transmission and reflection for any system of isotropic, anisotropic and dichroic layers. Additionally, the calculations takes into account real conditions of a display working. Basing of this model the computer program is done. This program makes it possible to conduct the complete optimization procedure for very complicated system such as for example color liquid crystals display. [ABSTRACT FROM AUTHOR]