高動態對比演算法用於免彩色濾光片免偏振片之節能顯示器

Abstract

近年來能源的問題愈來愈嚴重，但液晶顯示器的出光效率卻不到10%。從一開始的背光模組到電晶體、彩色濾光片、偏光片、液晶層等，每一個元件都會降低顯示器的出光效率，然而，在這些元件裡，又以偏光片和彩色濾光片的出光效率最差，因此若可以去除偏光片和彩色濾光片的話，出光效率可達到將近40%。 目前，時序型顯示器可成功地移除彩色濾光片，而高分子分散液晶材料(PDLC)可在不用偏光片的情況下讓液晶產生對比，本論文提出的節能顯示器是建立在時序型顯示器與高分子分散液晶材料的基礎上且結合使用發光二極體的光源，進而提出一高動態對比的技術(High Dynamic Range technology)以維持影像品質。在有使用此高動態對比的技術平均的表現都會比沒有使用此高動態對比的技術來的好，且在高分子分散液晶材料的對比愈小時，兩者的差距愈大。另外，在有使用此高動態對比技術的人因實驗結果裡，當高分子分散液晶材料的對比高於70:1時，人眼均感覺不出差別，而此時的平均色差僅在0.5左右，色差大於3的百分比約為3%。另外，在移除了彩色濾光片與偏正片之後，本論文更引入了120Hz Stencil-FSC法和白光發光二極體，當白光發光二極體的效率在100lm/W的狀況下，與傳統的時序型顯示器比較，此節能顯示器的耗光量更可大幅降低至原先的13%。

In recent years, the energy concerns are increasing around world. However, the optical throughput of the liquid crystal display (LCD) is less than 10%. The backlight module, the TFT array, the color filter, the polarizers, and the liquid crystals reduce the optical throughput. Moreover, the color filter and the polarizers are the two elements wasting the most light. Thus, lacking the color filter and polarizers, the LCD can enhance the optical throughput to 40%. The FSC-LCD successfully removes the color filter, and the polymer dispersed liquid crystal (PDLC) does not need the polarizers. The thesis will propose an Eco-display. Based on the FSC-LCD and the PDLC concepts, the thesis will propose a High Dynamic Range (HDR) technique, the Contrast Dependent Dimming Method, by using the LED light source to maintain the image quality. The simulation results show the image quality is better with the Contrast Dependent Dimming Method. When the contrast of PDLC becomes lower, the Contrast Dependent Dimming Method modifies the image quality more. Besides, the psychophysical experiment results show that when the contrast ratio becomes lower than 70:1, the human vision system starts feeling the differences. The psychophysical experiment result corresponds to the average ΔE=0.2 and 3% ΔE>3. Moreover, the thesis will further incorporate the 120Hz Stencil-FSC and the white LED. Assuming the efficiency of the white LED is 100lm/w, the Eco-display can further reduce the optical power to 13% of the convention FSC-LCD.