利用Stencil-FSC法抑制色分離並達低功率之色序型液晶顯示器

Abstract

色序法顯色技術是將各色場畫面時序顯示，利用人眼視覺暫留之特性，經由時間混色法即可得到一全彩畫面。此技術應用於液晶顯示器將可省去彩色濾光片的使用，因此該顯示器可提升光效率，具備低功率消耗，高影像解析度，高色彩飽和度，以及低成本的優點，深有發展為次世代顯示器之潛能。然而應用色序法型顯示器存在一嚴重問題，色分離現象，此將影響影像品質，且使觀測者感到不適。近年來，已有許多方法被提出來抑制色序法液晶顯示器之色分離現象，然而這些方法仍面臨許多問題，如：液晶反應速度以及影像失真…等，因此，色序型液晶顯示器遲遲未能成為當前的主流顯示技術。 基於以上論述，在此論文中，我們提出一新Stencil-FSC法來抑制色序法液晶顯示器之色分離現象。此新色序法為一四色場色序法，跳脫傳統色序法只顯示單色影像於各子畫面之限制，而顯示彩色畫面於子畫面中。利用第一個彩色色場顯示大致畫面，再使用紅、綠、藍三色場來顯示影像細節。藉由Stencil-FSC法將可降低紅、綠、藍三色場之色彩以及亮度，因此色分離的現象將可有效被抑制。此法在利用軟體模擬以及實際32吋場色序型液晶顯示器實體驗證後，不僅色分離問題可被大幅改善，且其對比可提升至5000:1，NTSC值為114%，且平均功率消耗降為40W。(現行32”LED背光液晶顯示器平均功率消耗約為180W;32”CCFL背光液晶顯示器平均功率消耗約為105W)

The color sequential technique is a kind of display mechanisms. The field images with different colors light in time sequence, by human eyes integration, a colorful image can be generated by temporal color mixing. The technique utilizing on LCDs called Field Sequential Color –LCD (FSC-LCD) can remove the color filters in displays, so it has several advantages, such as low power consumption, feasibility of high resolution, high color saturation, and low cost. Therefore, the FSC display has high potential to be a next generation display system. However, the FSC-LCDs have a serious issue, Color breakup (CBU), and it will degrade the image quality and make viewers uncomfortable. In resent years, several methods have been proposed to suppress CBU; nevertheless, the methods have some issues, like image distortion and limitation of LC response time…etc. Therefore, the FSC-LCD has not become a commercial display yet. In the thesis, a color sequence called Stencil Field Sequential Color (Stencil-FSC) method was proposed to suppress CBU. Stencil-FSC is composed by four fields in each frame. The concept of displaying single-color field images of conventional color sequence is modified, and a multi-color image is utilized in the Stencil-FSC method. The multi-color image is displayed in first multi-color field, and red, green, and blue fields were utilized to add color details. By the method, the color and luminance of red, green, and blue field are reduced, and it is helpful to suppress CBU. Simulation and demonstration on a 32” FSC-LCD have been implemented to verify the CBU suppression of the method. Moreover, the FSC-LCD achieved the contrast ratio of 5000:1, NTSC of 114%, and the average power consumption is only 44W (Conventional 32” CCFL-LCD is 105W, and 32” LED-LCD is 180W).