LED球泡灯寿命快速评估方法的研究

发布时间：2018-01-22 06:04

  本文关键词： LED 光通量 寿命 激活能 加速试验 可靠性　出处：《北京交通大学》2017年硕士论文　论文类型：学位论文

【摘要】：发光二极管LED(light-emitting diode)近几年来在我们的日常生活中并不陌生,已经成为第四代照明光源。然而,其理论寿命长达数10万小时,与实际寿命有很大的差别,在国际上目前没有关于LED照明产品寿命评估的统一标准。因此,如何快速有效的评估其寿命成为照明领域迫切需要解决的问题。本论文针对LED球泡灯,提出了一种快速评价寿命的方法。为方便建立不同环境温度下加速应力与LED照明产品寿命之间的联系,需要知道不同环境温度对应的具体LED结温大小以及LED的激活能,所以要测试结温和激活能。因此,本论文的主要工作如下:(1)进行了 LED激活能的计算研究,通过恒定温度加速寿命试验,测试出在两个不同环境温度下产品的光通量,利用指数衰减模型和阿伦尼斯模型计算出了LED产品的激活能。由于计算激活能时需要知道LED的结温,所以还进行了 LED结温的测试试验,通过正向结电压法,计算出了 LED球泡灯的温度系数以及在不同温度下工作时的结温。(2)对白光LED球泡灯快速评估寿命进行了研究,提出了三步法。第一步粗评,根据LED产品的固有属性,给出LED寿命的一个大致区间;第二步,通过加速寿命试验,预估出寿命;第三步,为了得到较为科学合理的预期寿命,充分考察次要因素的影响,借助模糊数学工具,采取模糊评判的方法对第二阶段给出的产品预期寿命值加以必要的修正。鉴于实验条件的限制与未联系下专家填写问卷调查表,第一步与第三步只是给出了一个粗略的方案。在第二步中,为了快速评估寿命,设计了可以缩短试验时间的加速寿命试验,在不改变老化机理的前提下,以温度作为加速应力,光通量的衰减作为失效判据,在2000h内对LED的寿命做出了评估。对试验样品在三种不同温度下进行了恒温加速寿命试验,通过测试样品在三种不同温度下在不同时间的光通量,对产品的寿命使用威布尔分布描述,加速寿命使用阿伦尼斯模型描述,结合最小二乘法对所测得的光通量数据经过数学计算和统计分析,最终外推出了在常温(25℃)下LED球泡灯的寿命。三步法是本论文的创新之处。
[Abstract]:Light emitting Diode (LED(light-emitting) has become a 4th generation lighting source in our daily life in recent years. Its theoretical life span is up to 100,000 hours, which is very different from the actual life. There is no uniform standard of LED lighting product life evaluation in the world at present. How to evaluate its life quickly and effectively has become an urgent problem in the field of lighting. This paper aims at LED bulb lamp. In order to establish the relationship between the accelerated stress and the life of LED lighting products at different ambient temperatures, a rapid method for evaluating the life of LED lighting products is presented in this paper. We need to know the specific LED junction temperature corresponding to different ambient temperatures and the activation energy of LED, so we need to test the junction mild activation energy. The main work of this thesis is as follows: (1) the LED activation energy is calculated and studied. The luminous flux of the product at two different ambient temperatures is measured by accelerated life test at constant temperature. The activation energy of LED products was calculated by exponential attenuation model and Arrhenis model. Because of the need to know the junction temperature of LED when calculating the activation energy, the test of LED junction temperature was also carried out. By the method of forward junction voltage, the temperature coefficient of LED bulb lamp and the junction temperature of white light LED bulb lamp working at different temperature were calculated and the rapid evaluation life of white light LED bulb lamp was studied. In this paper, a three-step method is proposed. The first step of rough evaluation is to give an approximate range of LED life according to the inherent properties of LED products. The second step is to estimate the life by accelerated life test. The third step, in order to obtain a more scientific and reasonable life expectancy, fully investigate the influence of secondary factors, with the help of fuzzy mathematics tools. The method of fuzzy evaluation is adopted to modify the life expectancy of the second stage. In view of the limitation of the experimental conditions and the lack of contact, experts fill out the questionnaire. The first and third steps only give a rough scheme. In the second step, in order to evaluate the life quickly, the accelerated life test which can shorten the test time is designed, without changing the aging mechanism. Using temperature as acceleration stress and luminous flux attenuation as failure criterion, the lifetime of LED was evaluated in 2000h. The constant temperature accelerated life test was carried out at three different temperatures. By testing the luminous flux of the sample at three different temperatures at different time, the life of the product is described by Weibull distribution, and the accelerated life is described by the Arrhenis model. Combined with the least square method, the lifetime of the LED bulb lamp at 25 鈩，

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