Content 中文摘要…………………………………………………………………I Abstract…………………………………………………………………II 誌謝…………………………………………………………………….III Content…………………………………………………………………IV Table captions………………………………………………………….VI Figure captions………………………………………………………..VII Chapter 1 Introduction………………………...……………………….1 1.1 Overview…………………………………………………………1 1.2 Motivation……………………………………………………….2 1.3 Thesis organization……………………………………………...4 Chapter 2 Basic theory …………………………………………………6 2.1 LED basics……………………………………………………….6 2.1.1 Basic electroluminescence theory………………………..6 2.1.2 Internal, extraction, and external efficiency…………….7 2.1.3 The Lamertian radiation pattern………………………...8 2.2 Geometry optical theory………………………………………12 2.2.1 Law of Reflection and Refraction………………………12 2.2.2 Fresnel Loss………………………………………………13 2.2.3 Total Internal Reflection (TIR)…………………………14 2.3 Absorption and extinction coefficient theory………………...16 2.4 Radiometry and photometry………………………………….19 2.5 Optical model in TracePro…………………………………….21 2.5.1 Bulk scattering…………………………………………...21 2.5.2 Bidirectional Scattering Distribution Function………..22 Chapter 3 Improvement of light extraction efficiency via surface roughing……….………………………………………….25 3.1 Physical model of the flip chip LED………………………….25 3.2 Different rough surface………………………………………..28 3.3 Result and discussion………………………………………….30 Chapter 4 Optical design and simulation of the LED lamp………..37 4.1 Physical model of the LED lamp……………………………..37 4.2 Building LED model…………………………………………..41 4.3 Result and discussion………………………………………….43 4.3.1 Model I…………………………………………………...43 4.3.2 Model II…………………………………………………..44 Chapter 5 Conclusion………………………………………………….48 Reference……………………………………………………………….49 Table Captions Table 1-1 The color of LEDs which are manufactured from different semiconductor material [1.1]………………………………2 Table 2-1 Photometric quantities [2.5]……………………………...20 Table 2-2 Photometric quantities [2.5]……………………………...20 Table 3-1 The thickness and optical properties of each layers……...27 Table 3-2 The mechanical dimensions of the flip chip LED………...27 Table 3-3 The simulation results of the rough surface with different separation between the center of each holes………………32 Table 3-4 The simulation results of the rough surface with different depth…………………………………………………………33 Table 3-5 The simulation results of the rough surface with different bottom width………………………………………………...34 Table 3-6 The simulation results of the rough surface with different opening width………………………………………………..35 Table 4-1 Comparison of simulation and experiment results on θ1/2…………………………………………………………….46 Figure Captions Fig. 1-1 The simulation flow chart in this thesis………………………3 Fig. 1-2 The organization flowchart of this thesis……………………..4 Fig. 2-1 LED p-n junction under (a) zero bias and (b) forward bias [2.1]……………………………………………………………..7 Fig. 2-2 Geometrical model used to derive the Lambertian radiation pattern. (a) A light ray emitted from the point-like source (b) The area element dA of the sphere [2.1]……………………...9 Fig. 2-3 LED with (a) planar, (b) hemispherical, and (c) parabolic surfaces. (d) Far-field radiation patterns of the different types of LED (a), (b), (c)[2.1]………………………………...11 Fig. 2-4 Relationship between a ray incident on a plane surface and the reflected and refracted rays…………….………………..13 Fig. 2-5 Total internal reflection (TIR) occurs when a ray, passing from a medium of higher to a lower refractive index………15 Fig. 2-6 The relative sensitivity of the eye to different wavelengths for normal levels of illumination (Daylight vision) and under conditions of dark adaptation (Night vision)……………….19 Fig. 3-1 Schematic structure of the flip chip model………………….26 Fig. 3-2 The flip chip model in the 3D structure and 2D structure (top view)…………………………………………………………...27 Fig. 3-3 The SEM image of the rough surface structure…………….28 Fig. 3-4 The rough surface structure in the 3D and 2D (top view)....29 Fig. 3-5 The dimensions of rough surface structure…………………29 Fig. 3-6 The variation of light extraction efficiency with the separation reducing…………………………………………..32 Fig. 3-7 The variation of light extraction efficiency with the depth reducing…………………………………………………….....33 Fig. 3-8 The variation of light extraction efficiency with the bottom width increasing…..………………………………………….34 Fig. 3-9 The variation of light extraction efficiency with the opening width increasing………………………………………………35 Fig. 4-1 The geometry of the LED of Luxeon emitters………………38 Fig. 4-2 The geometry of the P5 series InGaN LED chips……..……39 Fig. 4-3 The 3D structure of the Lambertian type LED……….…....40 Fig. 4-4 InGaN flip chip model I……………………………………...41 Fig. 4-5 InGaN flip chip model II……………………………………..42 Fig. 4-6 Radiation pattern (in polar coordinates) of simulation results of model I together with experiment results………………...43 Fig. 4-7 Radiation pattern (in rectangular coordinates) of simulation results of model I together with experiment results………..44 Fig. 4-8 Radiation pattern (in polar coordinates) of simulation results of model II together with experiment results……………….45 Fig. 4-9 Radiation pattern (in rectangular coordinates) of simulation results of model I together with experiment results………..46