基于封装技术的大功率白光LED光效和色温的研究

论文摘要

大功率LED与传统光源相比,具有节能、寿命长、环保、体积小、响应速度快、可靠性高、调控方便等突出性能,正作为一种新型照明光源并获得越来越广泛的应用。但是大功率LED同时也存在发光效率低和色温偏高的发展瓶颈。本文制备了不同参数的荧光粉胶饼,设计了不同镀层材料的反光杯,采用两种荧光粉远离芯片结构对LED进行了封装。并通过电子衍射分析仪（XRD）、光学显微镜、拉曼光谱分析仪、积分球和PMS-50增强型光谱分析系统表征了荧光粉的相成分、荧光粉胶饼的光学性能以及LED的光效和色温等参数。在制作荧光粉胶饼的过程中,面临着两个主要的问题:荧光粉沉淀和荧光粉团聚。通过对荧光粉胶饼的金相组织观察发现超声振动对于荧光粉分散的均匀性有很显著的效果。而超声振动和真空脱泡则有助于减少荧光粉胶饼中的气泡,改善其光学性能和出光均匀性。通过对荧光粉胶饼进行拉曼光谱分析得出结论:325nm紫外光激发时,随着荧光粉胶饼厚度的增加,黄光的光通量也随之增加;而在黄色荧光粉中加入一定比例的红色荧光粉,会使白光LED的光效下降而色温升高。对制备完成的荧光粉片采用两种荧光粉远离芯片封装结构进行封装,通过积分球和PMS-50增强型光谱分析系统对不同参数的LED的光效、色温和色坐标等参数进行了测量。测量结果表明,荧光粉远离芯片封装结构与传统封装方法相比,能够提高功率型白光LED的流明效率,并且能够降低色温。黄色荧光粉浓度为15.0%,荧光粉胶饼厚度为300μm时,LED出光性能较好,光效达到60.86lm/W,色温为6187。关于大功率LED光效和色温的改善是大功率LED发展历程,特别是商品化过程中的一个重要内容。由于封装很大程度决定了LED的光学性能,本课题的研究对大功率LED封装具有重要的实用价值。

论文目录

• 摘要
• ABSTRACT
• Acknowledgements
• Nomenclature
• List Of Tables
• List Of figures
• Introduction
• 1.1 Preface
• 1.1.1 Development of lighting
• 1.1.2 LEDs advantages
• 1.1.3 LEDs applications
• 1.1.4 Lighting principle of LEDs
• 1.1.5 Packaging materials of LEDs
• 1.1.6 Structure of white LEDs
• 1.1.7 Color temperature
• 1.2 The status quo for study on light efficiency and color temperature of high power LEDs
• 1.3 Research significance and content
• Experimental Materials and Methods
• 2.1 Experimental materials
• 2.1.1 Phosphor
• 2.1.2 Organic silicon casting glue
• 2.1.3 Chip
• 2.2 Experimental apparatus and equipment
• 2.3 Property characterization
• 2.3.1 X-ray diffracted ray （XRD）
• 2.3.2 Raman spectroscopy
• 2.3.3 Text of light efficiency and color temperature of LEDs
• Preparation of Phosphor Compound Film and Test on Its Relevant Performance
• 3.1 Preface
• 3.2 XRD phase component analysis of phosphor
• 3.3 Preparation of phosphor compound film
• 3.4 Dispersion uniformity of phosphor
• 3.4.1 Phosphor sedimentation
• 3.4.2 Particle agglomeration of phosphor
• 3.5 Optical metallographic observe of phosphor compound film
• 3.6 Raman spectrum analysis of phosphor compound film
• 3.7 Chapter summary
• Packaging and Performance Test of LEDs
• 4.1 Preface
• 4.2 Light reflector
• 4.3 Structure and packaging flow of LEDs
• 4.3.1 Dispensing
• 4.3.2 Packaging structure that phosphor isolates from the chip
• 4.4 Experimental results and discussion
• 4.4.1 Influence of different packaging structures on the light efficiency and color temperature of white LEDs
• 4.4.2 Influence of different phosphor on the light efficiency and color temperature of white LEDs
• 4.4.3 Influence of phosphor compound film thickness and phosphor concentration on the light efficiency and color temperature of white LEDs
• 4.4.4 Influence of the one to add the red phosphor on the light efficiency and color temperature of white LEDs
• 4.4.5 Influence of material of light reflector on the light efficiency and color temperature of white LEDs
• 4.4.6 Influence of material of light reflector on the light efficiency and color temperature of white LEDs
• 4.5 Chapter summary
• Conclusion
• References