2014人教版语文七下《猫》PPT课件之三.ppt

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2012 届毕业(设计)论文
题目 LED结温测试技术的研究
专业班级 2008级应用光电子01班
学号 0809040132
学生姓名
学院
指导教师
指导教师职称
论文成绩
完成日期: 2012年 6月 3日
LED结温测试技术的研究
Investigation on the measuring methods of LED junction temperature
摘要
随着半导体科学的发展,发光二极管(LED,Light Emitting Diode)因其效率高、寿命长、可靠性高等特点等优点正向普通照明领域迅速普及,然而LED器件的热特性检测和散热是一个突出的问题,如何保持LED的结温在允许范围内,使LED始终获得稳定的光输出和维持正常的器件寿命,一直是一个当前急待解决的课题。
本文简单介绍了LED的发展历程、发光原理、应用前景和国内外研发生产现状。研究了大功率LED发光原理,分析了LED的热学特性及热学参数,阐述了LED的结温产生的原因,以及LED结温对于其热特性的影响。
提出了LED结温测量的几种方法,并对几种方法进行了比较。重点提出了一种新的非接触式结温测试法-蓝白比法,不仅可以测量单颗LED的结温,还可非接触、快速测量LED阵列的结温分布。
蓝白比法是一种非接触LED结温测量技术,特别是对于大功率白光LED。利用LED管光谱中W/B都随结温呈现线性变化,说明大功率白光LED的结温非接触光谱测量方法是可行、可靠的。
关键词:LED :结温热特性:结温测量:蓝白比法

Abstract
With the development of the semiconductor material technology, LED meets the requirements of low-carbon economy because of their high energy saving efficiency, long life—time and high reliability, and it is, widely used in many fields especially the fields of semiconductor lighting. However, the test of hermal performance and heat dissipation is still a prominent order to obtain stable light output and maintain normal lifetime of the devices, how to keep the junction temperature within the allowable range? This is still a burning question at present.
A brief introduction of the LED development process, the history of LED , the theory of LED, application prospect and the status of the study of LED around the world included in this paper. Investigated the principle of the high power LED light, analyses thermal characteristics and thermal parameters of LED, elaborated the causation of LED junction temperature, as well as LED junction temperature for the thermal properties.
The measuring methods of LED junction temperature is introduced in this paper, and several method pared . A new non-contact method based on relative radiation intensity is proposed, blue and white ratio method , which is suitable for one single LED or the average junction temperature of LED array.
The dissertat