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Recent progress in both low pretilt and high pretilt defect-free C1 surface stabilized ferroelectric liquid crystal (SSFLC) devices for e-paper application is reviewed. First, by using numerical calculation to investigate the balance between surface azimuthal anchoring energy and bulk elastic energy within the confined chevron layer geometry of C1 and C2, we found it is possible to achieve a zigzag-free...
In order to achieve a lower driving voltage of a cholesteric liquid crystal display (Ch-LCD) we formulated new nematic liquid crystal mixtures with dopants. The interesting thing is that the driving voltage is decreased more by adding the low molecular weight of liquid crystal materials in the cholesteric mixtures without decreasing its reflectivity. The cholesteric mixture is optimized by adding...
Blue to white to green light-emitting diodes with structure ITO/PVK:DPPhP(5%)/PBD(xnm)/Alq 3 (5nm)/LiF(0.3nm)/Al have been obtained. DPPhP (1,3-diphenyl-5-(9-phenanthryl)-4,5-dihydro-1-H-pyrazole), which performs good blue-emitting and hole-transporting properties, is synthesized and used as dopant. When the thickness of PBD layer varies from 0 to 5 to 10nm, green to white to blue emission...
Electrochromic reflective displays based on nanocrystalline metal-oxide working electrodes with chemisorbed organic electrochromic molecules have been developed. We have combined such electrodes with nanocrystalline capacitive counter electrodes, a white reflector layer, and an electrochemically inert electrolyte. Device components and process technology have been developed, resulting in direct-driven...
We review recent developments in the use of the phase separated composite organic film method and the fabrication of liquid crystal (LC) electro-optical devices using a single glass substrate using this method. The LC layer is confined between a film of solidified polymer layer on one side and the glass substrate on the other. The solidified polymer layer adjacent to and parallel to the LC layer is...
We are developing a new reflective display technology, based on total internal reflection, which achieves a large difference between the maximum and minimum reflectance values. This yields a surface with greatly improved legibility under a wide range of illumination conditions. Such devices can display an image with a maximum reflectance ranging from 55% under uniform background illumination to over...
Zinc-porphyrin dye molecules were incorporated into the backbone of a conjugated polymer material by a method, which allowed for the incorporation of only one zinc-porphyrin dye molecule into the backbone of each conjugated polymer molecule. The electronic properties of the homopolymer were established using ultraviolet photoelectron spectroscopy (UPS) for the determination of the electronic energy...
In order to achieve fast driving for reflective cholesteric liquid crystal display (Ch-LCD) we have developed a novel 3+2 dynamic driving scheme (3+2 DDS), which uses 3 and 2 level driver ICs for row and columns, respectively. From the transient dielectric study, the selection period of around 1.0ms/line showed the best contrast ratio at 30°C in our system. The time of the homeotropic to transient...
Polymer cholesteric liquid crystal (PCLC) flake technology is being developed as an alternative display technology for flexible, reflective particle displays. The motion of PCLC flakes suspended in a host fluid can be controlled with an electric field, creating a way to electrically control the flakes' ability to brightly reflect light that is circularly polarized. The PCLC flake/host fluid dispersion...
We demonstrate a flexible active-matrix liquid crystal display using organic thin film transistors (OTFTs) on polycarbonate substrates by employing a rubber stamp printing method. With surface modification of the gate insulator, OTFT with field effect mobility of 0.025cm 2 /Vs and on/off current ratio of 10 4 was achieved on a plastic substrate. Based on the results, we successfully...
Bragg gratings are holographically recorded in polymer dispersed liquid crystal materials to create a stratified composite material known as holographically formed polymer dispersed liquid crystals (H-PDLCs). Through a photo-induced diffusion-counter diffusion process, a refractive index modulation is permanently created. By choosing proper pitches of gratings and geometry, the gratings can be utilized...
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