分區掃描式色序法之液晶顯示器背光驅動控制系統

Abstract

TFT-LCD技術的高度發展，已經持續在改變著現代社會人們的生活方式。然而隨著顯示器的在影音多媒體上的應用，人們也發現了液晶電視在顯示動態圖像時會出現拖影和模糊的情形，這是顯示視訊影像所不能允許的。本論文研究即是R-G-B LED分別以區域掃描的方式來達到Impulse type的背光效果，藉以改善液晶顯示器因液晶反應速度慢及傳統Hold type背光模組所產生的動態影像模糊現象，以提昇動態影像的顯示效果。

另外，彩色濾光片為目前液晶顯示器最常採用的彩色顯色元件，然而其最大缺點則為光利用效率低；再加上關鍵材料-彩色光阻之解析度限制，目前仍無法達到可與報紙相同之精細度(200 dpi)要求。現今TFT-LCD僅有不到10%的光效率，提升光效率並降低功率損耗便成為現階段TFT-LCD研究的重要課題。彩色濾光片為TFT-LCD最大光功率損耗元件，彩色濾光片會損耗至少66%的光能量，同時還影響面板的色彩顯示品質。於是設計以三色分離RGB-LED陣列色序式掃描背光源取代傳統白色連續光譜光源，因典型LED發射光譜之半高寬小於100 nm，將能有效運用三原色個別光子能量，進而提升發光效率。構想為同一時間內只有單一顏色的LED發光，利用人眼視覺暫留與色彩加法混色的原理，可在時間區域上切割出全彩的影像畫面。此法不需要彩色濾光片，具有節省面板製造成本1/3 的優勢，能大幅降低光損耗率，提升發光效率，降低耗電量。

ABSTRACT

The TFT-LCD Display technology has rapid developed in the recent year that having more and more influence on our daily life. However, with regard to the LCDs that are applied to multimedia, the motion blur will be one of the main issues especially a fast moving object is perceived. Therefore, the quality of dynamic image will be deteriorated. For this reason, the aim of this thesis is to reduce the motion blur and improve the display quality by using partitioned scanning field-sequential-color LCD backlight, which can emulate the CRT's impulse type backlight effect.

Furthermore, most of the present LCD displays utilize the color filter to exhibit full color images. About 1/3 light energy was allowed to pass through the color filter. In addition, the resolution as high (200 dpi) as the newspaper cannot be achieved due to the configuration of RGB color filter. How to improve the light efficiency and reduce the power consumption for TFT-LCD seems a critical issue. We design a partially scanning backlight with RGB 3-in-1 full color LED to replace the traditional hold type white backlight. The concept is to turn on RGB LEDs in sequential and to scan the whole panel from top to bottom. Based on the "Human's vision suspend effect" and "Color Mixing effect", a full color image can be created. The LED has the superiorities in a very narrow spectrum and lead to a very wide color gamut. The proposed backlight configuration is expected to improve the optical performance in the TFT LCD system.