TFT-LCD電漿背光源之二維流體模式模擬

Abstract

CCFL因為能提供較高的效率與亮度，經常被使用在LCD 作為背光源。然而，CCFL因為含汞，在低環境溫度下點火較困難，相對的達到飽和亮度的時間勢必增長。此外，隨著環保意識的增強,各國已逐漸減少工業生產中的用汞量，並積極鼓勵採用無汞的新技術。 不含汞的平面電漿背光源已被發展。平面光源由於可以實現大面積均勻發光，壽命長，無污染等優點而備受重視。本研究使用二維流體模式模擬TFT-LCD之電漿背光模組的放電情況。在此流體模式中，考慮中性粒子、帶電粒子與激發態粒子的連續方程以計算各粒子的密度空間分布。電場空間分布則由帕松方程結合連續方程求得。semi-implicit的數值方法被引用以增加模擬時間差的長度。所有電漿參數的研究與討論主要為求得電漿背光源的最佳化。模擬幾何長度為20.5 mm，寬為9.4 mm。

Generally CCFL is used in LCD as backlight because it provides high efficacy and brightness. However, the use of mercury leads to difficulties in lamp ignition at low ambient temperature and a relatively long build-up time is necessary for the lamp to reach the saturated luminance level. In addition, a use of mercury is not recommended for environmental protection. A mercury-free flat discharge fluorescent lamp, plasma backlight, has been developed for LCD backlighting. This research uses a two-dimensional fluid modeling code to investigate the phenomenon of a plasma backlight module cell of TFT-LCD panel. In this fluid model, we have considered the continuity equations of neutral particles, charged particles and excited particles to calculate the density of each species spatial distribution. And we also use the Poisson's equation to calculate the electric field spatial distribution. A semi-implicit numerical method is applied to increase the length of . All plasma parameters are studied and discussed in order to find the optima of backlight source system. The time-dependent distributions of electron density, electron temperature, ion density and excited particles density are obtained during the discharge period in a plasma backlight cell. The two-dimensional simulation geometry length is 20.5 mm, and the width is 9.4 mm.