應用於照明系統之光度學量測與模擬方法

Abstract

各式各樣的通訊產品與影音媒體不斷推陳出新，驅策著光電科技日新月異，而光學元件之需求量也與日俱增。隨著照明及顯示技術之開發，同時具有反射、折射、發光、及散射之複合功能的光電材料被大量使用(如:白光二極體之黃螢光粉層)，而其量測技術、光學模型、及計算方法需相應隨之進步，以配合系統開發者的需求。 本論文以幅度學及光度學理論為基礎，針對複合光學特性之光學材料提出新式的量測儀器、光學模型、以及計算方法，以各式光學材料做為驗證，並以提出之流程應用於新式平面光源系統開發。 首先，本論文以雙方向散射函數描述光學特性，結合錐光量測儀，建立一套雙方像散射函數之量測平台，成功測量出散射元件之光學特性，並對其雙方像散射函數做定性分析。其次，以白光二極體中螢光粉層為目標，提出雙色雙方向散射函數描述其光學特性，論文中敘述了其數學定義、實驗方法、及計算驗證。 除了提出新式雙方向函數模型，本論文亦針對此類雙方向模型對於光與物質交互作用之積分計算開發一套演算法。以有限取樣疊加代替積分，與參考光源比較，疊代找出目標物之最佳取樣密度，論文中敘述了其數學操作方法，並以計算商用光學擴散膜片做為演算法驗證。 以上述提出之新式量測技術、光學模型、以及計算方法，本論文對於一新型外加螢光膜片之平面光源做為應用，其平面光源系統之發光二極體陣列密度、空腔厚度皆以新式流程做光學模擬及特性預測，最終以優化參數成功實作出原形模組。

Various communication and multimedia products are fast renewed, driving optoelectronics techniques to develop rapidly. As the progress of illumination and display technologies, multi-functional optoelectronics materials which simultaneously have the reflection, refraction, emission and scatter properties are commonly used (e.g. the yellow phosphor layer of white light emitting diodes). Thereby, the corresponding measurement technologies, optical modeling, and calculation methodologies should be developed for researchers. In this dissertation, basing on the radiometry and photometry, we proposed a specific measurement instrument, optical characterization, and calculation method for these multi-functional optoelectronics materials. The experiments of some materials were implemented for verification. Furthermore, the proposed procedure was applied on the development of a novel planer lighting system with remote phosphor sheet. Firstly, we used bidirectional scattering distribution function (BSDF) to describe the optical properties. A BSDF measurement instrument associated with a conoscopic system was created, and the properties of scattering components were measured. The BSDF data are also qualitatively analyzed. Most importantly, we proposed a dichromatic BSDF to characterize the optical properties of the yellow phosphor layer in a phosphor-converted LED. The mathematical definition, experimental method, and verification are stated in the thesis. In addition to the dichromatic BSDF, an algorithm was proposed to calculate the energy integration of the light-material interaction characterized by such bidirectional models. A discrete superposition was applied to implement the integration. Comparing with a reference light source, the optimized discrete sampling grid of the target sample would be found by an iterative method. The mathematical operation process is introduced in this thesis, and the proposed algorithm was verified by a commercially available diffusing sheet. By using the proposed measurement instrument, optical characterization, and calculation method, a novel planer lighting system with remote phosphor sheet was simulated. The arrangements of LED array and cavity thickness were optimized through this procedure. Finally, the prototype module of the planer light source was demonstrated by the optimized geometrical parameters.