Summary form only given. Alternating current plasma display panels (AC PDPs) are one of the most promising technologies for large-area flat panel displays. Many research and development activities have been carried out to improve display performances of AC PDPs such as luminance and luminous efficiency, resolution, lifetime and contrast ratio. However, their low efficiency is still an important drawback of PDPs. For high efficiency PDPs, many studies have been done to optimize geometrical parameters of a PDP cell, which is one of the main factors that determine luminous efficiency. Focusing our attention on the front dielectric layer, we have performed two-dimensional simulations of a coplanar structured AC-PDP cell. An AC PDP structure with a grooved front dielectric layer, which has a thinner front dielectric layer near the gap between two sustain electrodes than the other part of the front dielectric, has already been studied. Here, we have extended our manipulation of front dielectric to make multi-layered structures, in search of a high efficiency PDP with low operating voltage. In a two-layered front dielectric structure, we have found that the order of stacked dielectric layers with different dielectric constants influences discharge characteristics. According to our simulation results, the component dielectric layer with higher dielectric constant should be next to sustain electrodes to get higher efficiency and lower breakdown voltage. These results are very promising because we can not only reduce the breakdown voltage but also enhance the luminous efficiency of PDPs, by using an appropriate multi-layered front dielectric structure. In addition, these multi-layered dielectric structures can give more freedom to choose dielectric materials for the front dielectric layer of PDPs, considering the contact between the front dielectric layer and the sustain electrodes and the interaction between them.
Abstract Polyimide containing cinnamate moiety has a good potential ability as a photo-alignment material. However, the application of photo-alignment to manufacturing LCDs is still limited due to hard to generate of pretilt angle. In order to generate large pretilt angles, some technologies are introduced. One technology is to change the ratio of the imidization and another technique is to use homeotropic alignment material. We prepared polyimide (PI) blends with fluorinated PI to control pretilt angle. Atomic force microscopy images showed surface morphology change by addition of fluorinated PI with increasing alignment angle. Photo-reactive cinnamate moiety was introduced by interfacial reaction and photochemical reactivity was confirmed by contact angle and pretilt measurement. The pretilt angle of the LC cells was about 7.2°. Keywords: blending polyimideinterfacial reactionphoto alignmentpretilt angle Acknowledgments This work was supported by Seoul Research and Business Development Program.
With recent experiments to add He gas to the conventional Ne-Xe discharge gas mixture for high luminous efficiency plasma display panels, we have performed simulations on a coplanar structured alternating current plasma display panel sustained in the He-Ne-Xe gas mixture, by using the two-dimensional fluid model simulator. As the He concentration increases, luminance and luminous efficiencies increase but power consumption decreases, which agrees well with the recent experimental findings. He atoms increase the number of Xe*(P23) in the excited state and thus, the dimer emission is increased while the resonant line is reduced with the He content. As a result, the total vacuum ultraviolet emission is increased and higher luminance and higher luminous efficiency can be obtained. The enhanced mobilities of the ions in the gas mixture by adding He gas to the mixture also play an important role in increasing luminous efficiency.
The additive gas effect on the discharge time lag of the address pulse was investigated in an ac plasma-display panel (PDP) with a Ne+13% Xe gas mixture. A small amount of Kr, N 2 , and Ar gas, respectively, was added to a Ne+13% Xe gas mixture to improve the address discharge time lag of an ac PDP. It was found that the address discharge time lag was improved by adding a small amount of Kr gas (up to 2%) to the Ne+13% Xe gas mixture and thereafter worsened. In the case of the addition of Ar gas to Ne+13% Xe, the discharge time lag of the address pulse was not improved. The concentration of N 2 in the Ne+13% Xe gas mixture was varied from 0.013% to 0.187%, and its effects on the address discharge time lag were investigated. The time lag for the address discharge with a Ne+13% Xe+0.013% N 2 gas mixture was improved
We have investigated how bus electrodes affect discharge and luminous characteristics of a discharge cell. Three-dimensional simulations have been performed in a coplanar structured alternating current plasma display panel cell, with phosphor saturation effect taken into account. There exists the optimal position of bus electrodes for high luminance and luminous efficiency. Considering bus electrode thickness, we have found that in-bus structure is a promising candidate for high luminance, high luminous efficiency, and fast operation plasma display panels. Our simulation results would be very useful to understand the influence of bus electrode on characteristics of a plasma display panel cell, and would also provide a general guidance to improve its display performances.
We have performed simulations on a coplanar structured alternating current plasma display panel cell sustained in the ternary He-Ne-Xe gas mixture and its discharge characteristics were compared with those of the conventional binary Ne-Xe mixture, by using the two-dimensional fluid model simulator. Since plasma display panels use micro-discharges in the Xe mixed gas to generate vacuum ultraviolet light to excite phosphor for visible light emission, the condition of discharge gas mixtures is one of the main factors that determine luminous efficacy and thus, intensive studies on discharge gas mixture are essential to optimize it. As the He concentration increases in the He-Ne-Xe mixture, luminance and luminous efficacy increase but power consumption decreases, which agrees well with the recent experimental findings. We have found that the enhanced ion mobilities in the gas mixture by adding He gas to the conventional Ne-Xe mixture play an important role in increasing luminous efficacy of a plasma display panel cell, by reducing the cathode fall potential. In addition, He atoms increase the number of Xe/sup */(/sup 3/P/sub 2/) in the excited state and thus, the dimer emission is increased while the resonant line is reduced with the He content. As a result, the total vacuum ultraviolet emission is increased and higher luminance and higher luminous efficacy can be obtained.
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