本研究提出一種應用於LED直下式背光模組的光場分布演算技術，由於LED直下式背光模組中的燈箱厚度大多數小於2.5公分，相較於透鏡尺寸明顯未滿足遠場條件，因此本研究利用幾何概念針對此透鏡出光面進行切割，分成數個子光源，這些子光源具有滿足遠場條件之特性，即可將原先的面光源視為無數的類點光源組合而成，當成為點光源的好處是我們可以藉由點光源的配光曲線及光源與偵測面間的距離迅速的計算出該點光源在偵測面上的照度分布，當我們理解該面光源在任意位置下的照度分布結果，就方便我們針對透鏡進行優化，進而達成燈箱需求。 單光源照度分布演算技術針對一顆與廠商開發之二次光學透鏡進行幾何切割，並利用不同子光源對應偵測點相對位置與其光強度分布，建立一套自製的光場分布演算技術，並使用光學模擬軟體驗證其演算技術結果，但要驗證其可行性使用單光源進行比對是有失可信度，因此我們必須藉由一個完整的模組去探討其可信度。使用演算及模擬方法建立一個大小為24吋燈箱厚度2公分的燈箱，並運用將光源函數二次微分找到其最佳間距，從結果來看演算法所得最佳間距模擬得到均勻度結果為84.7%與上述演算法得到均勻度結果為85.9%，顯示具有一定吻合性。 ;In this thesis, we will propose optical field calculation method for LED direct backlight module, as the LED direct backlight module in the light box thickness of most of less than 2.5 cm the compared to the lens size obviously did not meet the far field conditions . Therefore this study uses the concept of geometric concept to make source surface into regular sub-light sources,the size of the sub-light sources are more smaller that can reach far-field condition in same project distance.The advantage of becoming a point source is that we can quickly calculate the illuminance distribution of the light source on the detection surface by the light distribution curve of the light source and the distance between the point light source and the detection surface,we understand the surface of the light source in any position under the illumination distribution results to facilitate our optimization for the lens and then to achieve the requirements of light box. Single light source optical field calculation method for a secondary optical lens is divided into numerous sub-light source.Further,using the relative position of an point source and detection point to establish an optical field calculation method and use optical simulation software to verify the results of its calculation,but to verify its feasibility to use a single light source for comparison is a loss of credibility, so we must rely on a complete backlight module to explore it credibility. Using a calculus and simulation method to create a light box with a size of 24 inches and a thickness of 2 cm and use the secondary differential for the light spread function to find the best spacing. From the algorithm to obtain the best spacing simulation obtained uniformity of the results of 84.7%,with the optical field calculation method to uniformity results for 85.9%, the result all shows that thic techic has high accurate and high reliability.
