多重性能薄膜應用於高效率背光模組

Abstract

液晶電視(LCD-TV)與傳統陰極射線管電視相比，其具有高解析度、低功率、輕薄等優點，可以提供較佳的影像品質。直下式背光系統是目前的主要趨勢用來提供液晶電視的足夠亮度光源。然而，這種背光系統卻面臨了高價格和亮度不均勻(lamp-Mura)等問題。為了改善這些問題，本論文提出一種新型的光學薄膜，成功地有效提升背光系統的效能，並且減少其光學薄膜成本。 與傳統的增光膜(brightness enhancement film)比較，本論文提出的新式光學薄膜，「多重效能薄膜(Multi-Performance Film, MPF)」，在表面上具有凹狀拋物面稜鏡結構，因而同時具有增光和散射的特性。藉由模擬和實驗結果，MPF成功地消除lamp-Mura並且增加背光系統的亮度視角及光輸出效率。 然而，當進一步降低背光系統的厚度時，MPF在消除lamp-Mura有其極限。因此，本論文藉由「非均勻多重效能薄膜(Patterned-MPF)」來改善薄型化背光系統的lamp-Mura。Patterned-MPF乃是對應距離燈管不同位置對凹狀拋物面稜鏡的曲率進行優化。經由模擬結果驗證，薄型化背光系統的確產生均勻的光場輸出，並且有效地消除lamp-Mura。

Liquid crystal display TVs (LCD-TVs) have advantages, such as high definition, low power-consumption, and light weight, etc, which can produce a higher quality image. Direct-emitting backlight systems are needed to provide a sufficiently bright and uniform light source for LCD-TVs. However, the direct-emitting backlight system has some issues, such as high cost and lamp-Mura defect. Thus, a novel optical film is proposed to resolve these issues in this thesis. Compared with a conventional brightness enhancement film (BEF), the proposed multi-performance film (MPF) includes concave-parabolic prism structures on the surface. Thus, the MPF can integrate the brightness enhancement and light scattering functions simultaneously. According to the simulation and experimental results, MPF successfully suppressed lamp-Mura and enhanced the optical performance in backlight systems. When the backlight thickness is reduced, MPFs have a limited capability to suppress lamp-Mura. Therefore, a Patterned-MPF modified from the original MPF is designed to suppress lamp-Mura in a slim backlight system. The Patterned-MPF has optimized prism profile curvatures depended on the position from lamps. From simulation results, a slim backlight system with a uniform light output was achieved.