Search

Recent development of optical compensation scheme for liquid crystal display (LCD) enables to realise a high quality display by eliminating the unnecessary birefringence at oblique viewing directio...

An efficient ultraviolet (UV) polariser based on multi-layered carbon nanotubes (CNTs) which is obtained by set of CNT films attached to substrate in series with matching orientations is demonstrat...

Liquid crystal displays (LCDs) for vehicle displays should exhibit a fast response time in wide temperature range and wide-viewing angle in horizontal and downward directions without grey-scale inversion but limited brightness in the upward direction because the display images can be reproduced in the front window glass of a vehicle, affecting driver’s front visibility. Currently, fringe-field switching (FFS) liquid crystal device is widely commercialised for high resolution and wide-viewing-angle LCD; however, it needs to improve response times and limit the display brightness in the upward direction. As a solution, we propose a homogeneously aligned liquid crystal device in which liquid crystal director does tilt as well as twist deformation in a confined area by both vertical- and fringe-electric fields, exhibiting about two times faster decay response time than that of conventional FFS mode with suppressed luminance in the upward direction. The proposed liquid crystal device can be applied to ...

Optically isotropic nature can open a new type of high-performance liquid crystal (LC) displays. The main features emerge from the interaction between LC and polymer network at the interface. At this point, we investigated the influence of cross-linking monomer concentration and functionality on electro-optic properties of optically isotropic liquid crystal (OILC) obtained by polymerisation-induced phase separation method. Interestingly, we obtained a pore-like network structure constructed by highly interlinked polymer beads in acrylate monomers and achieved fast decay response time (0.6 ms). We found that the voltage-dependent hysteresis was mostly eliminated (~0.25%), and the contrast ratio was enhanced (1:1550) for high functional monomers. The result inspires a simple way to optimise the materials to fabricate a high-performance OILC device and it shows high-transparency, low-driving voltage, hysteresis-free and sub-millisecond response time.

Uniformly aligned liquid crystals (LCs) are of crucial importance in a practical application, such as displays, phase modulators and virtual reality devices. Although an alignment layer using polyimide-type polymers can almost perfectly align the LCs, polymer-stabilisation at the surface using pre-mixed monomers has been attempted to reduce the fabrication process, i.e. eliminating the alignment layer, thereby reducing the fabrication cost. Here, we propose an approach to achieve a homogeneous alignment of LCs by controlling the molecular structure of reactive monomers mixed in LCs without using conventional polyimide alignment layer. The result shows an excellent initial dark state and acceptable electro-optic performance which implies that the polymer stabilisation at the surface successfully anchors the homogenous orientation of LCs. We believe that the proposed fabrication method can contribute to cost-effective fabrication process by eliminating an alignment layer with no fabrication step of ...

The complete mitochondrial genome sequence from the Asian crested ibis, Nipponia nippon (Aves, Pelecaniformes, Threskiornithidae), was determined and characterized in detail. This mitochondrial gen...

Otologic accompanying symptoms, audiogram patterns, and hearing levels according to tumor size differed in patients with CPA tumors classified as VS and non-VS types.The diagnosis of CPA tumors is often delayed. Late-diagnosed tumors can grow until they compress and damage vital structures. This study evaluated the otologic symptoms and results of audiologic tests in patients with vestibular schwannomas (VS) and other types of CPA tumors.This study included 171 patients with otologic symptoms who were diagnosed with CPA tumors, including 116 with VS and 55 with other types of CPA tumors. Factors analyzed retrospectively included tumor type, size, and location and the results of audiometric examinations.The most common chief complaint in patients diagnosed with CPA tumors was asymmetrical hearing loss, with most frequent accompanying symptoms being tinnitus in patients with VS and dizziness in those with other types of CPA tumor. The most frequent patterns of hearing loss were the descending type in patients with VS and the flat type in patients with non-VS tumors (p 0.05). Pure tone thresholds tended to increase more in patients with VS than non-VS tumors according to tumor size, and pure tone averages were significantly higher in patients with VS than non-VS tumors of 11-25 mm in size (p 0.05).

Many patients with acoustic neuroma (AN) experience hearing loss and tinnitus. Time from first symptoms to diagnosis can be considerable. AN should be suspected, and MRI scans performed, in patients with hearing loss accompanied by asymmetry, tinnitus, low speech discrimination score (SDS), and abnormal auditory brainstem response (ABR).To determine the otorhinolaryngological factors associated with AN by analyzing the clinical manifestations and diagnostic test results of patients with AN before MRI scanning.This study enrolled 114 patients definitively diagnosed with AN after visiting the Ear-Nose-and-Throat and Neurosurgery Departments of Kyung Hee University Medical Center from 2001 to 2013. Factors retrospectively analyzed included patient age, gender, major symptoms, accompanying symptoms, symptom duration, pure-tone audiometry, SDS, asymmetry, tinnitogram, ABR, and MRI scan results.The main symptom of AN was hearing loss, and the most frequent accompanying symptom was tinnitus. More severe deafness correlated significantly with lower SDS (p0.05). Asymmetric hearing was observed in 75 of 116 patients (64.6%), and mean SDS was 73.1 ± 34.1%. Of patients with latencies of waves I, III, and V on ABR tests, 56.1%, 92.4%, and 92.4%, had interaural latency differences ≥0.2 ms. However, audiometry results did not correlate with lesion site or tumor size (p0.05).

The fringe-field switching-liquid crystal display (FFS-LCD) mode recently became a major component of LCDs for high resolution, high-image quality, low power consumption, and touch screen suitability. This review paper discusses how the FFS technology was developed, how it evolved to its present status, and also about the future advances of the FFS mode in terms of performance and technologies.

The circular F-type mitochondrial genome (15,761 bp) was completely sequenced for a Korean freshwater mussel Nodularia douglasiae (synonym Unio douglasiae; Unionidae, Unionida, Bivalvia). It contains 13 PCGs, two rRNA genes, and 22 tRNA genes, as generally shown in metazoan mitochondrial genomes. Its gene order is identical to that of F-type mitochondrial genomes observed in other freshwater mussels. With nucleotide and amino acid sequences of the complete F-type mitochondrial genomes obtained from 38 unionid species reported so far, phylogenetic analyses were done and discussed. The present study may give valuable helps to explore genetic diversity and population structures of other freshwater mussels as well as N. douglasiae.

Size- and aggregation-controlled dispersion of thin multiwalled carbon nanotube (t-MWCNT) in negative dielectric anisotropic liquid crystal (LC) material exhibits remarkable improvement in electro-optic response time in vertically aligned LC cells. The physical properties such as birefringence, dielectric anisotropy and clearing temperature of nanotube dispersed LC material appear to be almost invariant to that of pristine LC. Nevertheless, the response time shows noticeable improvement, especially in decaying time associated with transition from maximum to minimum transmission, hence important for faster switching LC devices. The effect is attributed to that vertically aligned t-MWCNTs along the field direction play role of vertical alignment layer between LCs, consequently resulting in increased bend elastic constant of LCs.

Wide-view (WV) film, which was introduced by Fuji Co., has been commercialized to block light leakage of twisted nematic (TN)-liquid crystal (LC) cells in a dark state when the viewing angles are in the off-axis direction. In this investigation, we designed an optical compensation structure of a TN-LC cell with an improved γ-curve, as well as a viewing angle property in the dark state. Basically, we used a pair of optical films consisting of a positive and a negative A-plate in order to avoid affecting the viewing angle property in the dark state. Then, we optimized the positive and negative A-plate to improve the viewing angle property in the gray levels by calculating polarization variations as a function of the optical axis and the retardation of the pair of the A-plates. From this calculation, we were able to show that the proposed normally white (NW) WV-TN cell exhibits wide viewing angle performance, including good γ-curve stability.

A transflective liquid crystal display using polymer-stabilised vertical alignment mode with fishbone-shaped electrode structure is proposed. Using the polymer stabilisation technique and patterned direction of pixel electrode structure, initial surface tilt angle and azimuthal angle can be well defined such that the liquid crystal is almost vertically aligned in the transmissive part while it has a certain pretilt angle that satisfies effective retardation of λ/4 with azimuthal direction of 45o with respect to the analyser in the reflective part. With optimisation of cell structures and surface tilt angles in the transmissive and reflective parts, a high performance transflective display showing excellent readability in any environment light conditions and single-gamma characteristic without using any retardation film or in-cell retarder can be achieved.

In order to compensate for light leakage in the oblique viewing directions of the dark state of the horizontal-switching mode such as the in-plane switching and fringe field switching modes. The viewing angle performance of the horizontal-switching mode with an compensation film has been evaluated on a case by case basis according to the retardation values of the films. Consequently, we found that a much better dark state can be achieved by using an optimised compensation film.

A device for operating viewing angle-switchable liquid crystal displays has been developed based on an optically isotropic liquid crystal (OILC). The device comprises two panels, main and switching. Depending upon the voltage applied, the optical state of the OILC layer in the switching panel can be changed to the anisotropic uniaxial state, taking on the role of a positive C film. In this manner luminance at oblique polar angles can be suppressed, resulting in a dark image at an off-normal axis, at the same time retaining good image quality in the normal direction. Depending on the switching of the OILC layer, wide or narrow angles of viewing can be obtained.

When a dielectric layer, in‐cell retarder (ICR) is formed between the electrode and LC layer to obtain a single‐gap transflective fringe‐field switching (FFS) display, the driving voltage is highly...

This paper investgates the transflective liquid crystal displays (LCDs) associated with fringe‐field switching (FFS) mode to achieve high image quality. In the past, several cell structures were used to fabricate transflective FFS LCDs. Their structures and characteristics are carefully examined to find their merits and demerits. In addition, we attempt to optimize cell parameters to achieve a single driving circuit.

We have studied the optically compensated splay (OCS) mode applied to polymer stabilization technique using polymerization of reactive mesogen (RM) to reduce or eliminate critical voltage, setting voltage, and phase transition time from bend to splay state. The pretilt angle of almost vertically aligned liquid crystal directors could be lowered through the polymerization of UV-curable RM and applied voltage, at surfaces of vertical alignment layers. To confirm initial stable splay state, we investigated electro-optic characteristics according to concentration of RM in this paper.

We demonstrated a novel viewing angle controllable display device in in-plane switching (IPS) mode with single panel. In the device, single pixel is separated into two regions, named as main pixel for displaying images and sub pixel for viewing angle control. Initially, the liquid crystal (LC) in sub pixel is homogenously aligned on substrate. For wide viewing angle mode, the LC switches in plane in the main pixel and for narrow viewing angle mode the LC switches the level of tilt angle without rotating by applying fringe electric fieldge. The proposed device is facilitated with simple manufacturing process and good viewing angle control with single panel.

We have fabricated carbon nanotubes (CNTs) doped homogeneously aligned nematic liquid crystal cells driven by fringe-field switching and their electro-optic characteristics were investigated. The CNTs doped liquid crystal cell shows lower transmittance, higher driving voltage but faster response time than those in the pure liquid crystal cell. In addition, CNTs-doped liquid crystal cells as a function of the CNT length were investigated. This paper gives an explanation on difference in electro-optic characteristics of pure and CNT-doped LC in the FFS mode.

We propose a pixel structure of viewing angle switchable liquid crystal display (LCD) associated with fringe-field switching (FFS) mode using one panel. In the device, one pixel is composed of main- and sub-pixel, in which the former has a role of image expression using the FFS mode and the latter has a role of viewing angle switching using the electrically controllable birefringence (ECB) mode. Consequently, before applying voltage to the sub-pixel, the device shows wide viewing angle, however, when the proper voltage is applied to the sub pixel, the displayed image is blocked in an oblique viewing angle.

The light modulation mechanism in conventional liquid crystal displays (LCDs) presents either phase retardation or polarization rotation effects only. However, in the fringe-field switching (FFS) mode, both effects exist depending on the electrode positions when the electrode width and distance is larger than 2 μm. Interestingly, when the electrode width and distance are reduced to less than 2 μm, only the polarization rotation effect exists. Further, reduction of the electrode width and distance gives rise to improved response time and light efficiency in the FFS mode.