修正疊紋透鏡概念以製作高效率擴散膜之研發

Abstract

擴散膜功能為提供液晶顯示器均勻的面光源，一般傳統的擴散膜主要是在擴散膜基材中，加入化學顆粒，作為散射粒子，然而於此架構下，材料本身及化學顆粒的光學特性，將會因為粒子吸光造成較高的亮度損失，且當空腔高度較低時，會產生擴散效果不彰之問題，為了改善上述兩種問題，本論文提出以疊紋透鏡概念用於改善擴散膜之穿透率以及擴散效果。 疊紋擴散膜的概念為兩組透明的半透鏡陣列進行疊合，當光進入微透鏡陣列時，透過微透鏡所產生之微聚焦、像差以及疊紋等光學效應，達到光源均勻化之目的。曡紋擴散膜具有許多優點：無化學顆粒，不會因粒子吸光造成穿透力下降的現象，而空間頻率不高以及一維幾何形狀使得製程較為容易，除此以外，具較佳的聚焦特性及光的偏折能力，故相較於傳統擴散膜擁有更好的擴散力。 此論文中分別從疊紋效應、幾何光學以及像差三種光學現象分別討論疊紋透鏡之擴散機制，接著提出疊紋透鏡最佳化之方式，最後比較疊紋透鏡與傳統擴散膜，評估疊紋擴散膜是否可以取代現有之擴散膜。當分析光學現象時，使用模擬軟體LightTools和Code V分別模擬光路追跡與透鏡資料，並以Mathematica處理數學問題。

This dissertation aims to discuss the diffuse effect of the overlaid cylindrical lens array by applying moiré phenomena, geometry optic, and aberration theorem. The diffuser in back light module is to diffuse light source, providing a uniform surface light. Traditional diffuser, using chemical particle to scatter incident light, has some disadvantages, including lower light transmission efficiency, and insufficient diffuse ability occurred as the interval to light source is too low. So as to resolving these problems, and overlapped cylindrical lens arrays, that is moiré lens, will be provided. Due to the moiré phenomena, short focal length of the micro-lens, and aberration, the moiré lens, the overlaid two half-cylindrical lens arrays have better diffuse effect. Using the moiré lens as a diffuser has many advantages. First, simple surface profile and one-dimension pattern simplify the fabrication process. Second, the absence of chemical particle avoids the light-absorbed problem; therefore, light transmission efficiency can be increased. Finally, the better diffuse effect of moiré lens can be achieved in short interval of film and light source. This dissertation will initially discuss moiré lens in three points: moiré phenomena, geometric optics, and aberration theorem. Then the optimizing model will be developed. Finally, in comparison with moiré lens and traditional diffuser, the possibility of replacing or recombining traditional diffuser will be discussed.