LED封装企业和LED照明灯具生产厂家都会遇到LED死灯现象,作为LED工程师怎么分析及解决这些问题?
LED死灯原因主要有以下两点:
1)LED的漏电流过大造成PN结失效,使LED灯点不亮,这种情况一般不会影响其它的LED灯的工作
2)LED灯的内部连接引线断开,造成LED无电流通过而产生死灯,这种情况会影响其它的LED灯的正常工作,
怎么预防LED死灯?
静电对LED灯来说是一种危害极大的魔鬼,全世界因为静电损坏的电子元器件不计其数,造成数千万美元的经济损失。所以防止静电损坏电子元器件,是电子行业一项很重要的工作,LED封装、应用的企业千万不要掉以轻心。任何一个环节出问题,都将造成对LED的损害,使LED性能变坏甚至失效。我们知道人体(ESD)静电可以达到三千伏左右,足可以将LED芯片击穿损坏,在LED封装生产线,各类设备的接地电阻是否符合要求,这也是很重要的,一般要求接地电阻为4欧姆,有些要求高的场合其接地电阻甚至要达到≤2欧姆。
人体静电对LED的损害也是很大的,工作时应穿防静电服装,配带静电环,静电环应接地良好,有一种不须要接地的静电环防静电的效果不好,建议不使用配带该种产品,如果工作人员违反操作规程,则应接受相应的警示教育,同时也起到告示他人的作用。人体带静电的多少,与人穿的不同面料衣服、及各人的体质有关,秋冬季黑夜我们脱衣服就很容易看见衣服之间的放电现象,这种静电放电的电压就有三千伏。
有些企业采用手工焊接,使用40瓦普通烙铁,焊接温度无法控制,烙铁温度在300-400℃以上,过高的焊接温度也会造成死灯,LED引线在高温下膨胀系数比在150℃左右的膨胀系数高好几倍,内部的金丝焊点会因为过大的热胀冷缩将焊接点拉开,造成死灯现象。
针对上述现象,LED封装厂家和LED照明灯具应用厂家应制定严格的LED标准使用手册,在生产过程中杜绝上线现象的发生。
LED packaging enterprises and LED lighting manufacturers will encounter LED dead light phenomenon, as an LED engineer how to analyze and solve these problems?
There are two main reasons for LED dead lights:
1) the leakage current of the LED is so large that the PN junction fails, making the LED light not bright. This situation will not affect the work of other LED lights in general
2) the internal connection lead of the LED light is disconnected, causing the dead light caused by no current passing through the LED. This situation will affect the normal operation of other LED lights.
How to prevent LED dead light?
Static electricity is a dangerous devil for LED lights. There are countless electronic components damaged by static electricity all over the world, causing tens of millions of dollars of economic losses. Therefore, to prevent electrostatic damage to electronic components, is a very important work in the electronic industry, LED packaging, applications of enterprises do not take lightly. Any link out of order, will cause damage to the LED, so that LED performance deterioration or even failure. We know that human body (ESD) static electricity can reach about 3,000 volts, which is enough to break down and damage the LED chip. In the LED packaging production line, whether the grounding resistance of all kinds of equipment meets the requirements is also very important. Generally, the grounding resistance is required to be 4 ohms, and even to be less than or equal to 2 ohms in some cases with high requirements.
Human body electrostatic damage to the LED is very big, work should wear antistatic clothing, equipped with electrostatic ring and static ring were good, there is a kind of don't need ground electrostatic ring antistatic effect is not good, suggest not use match this kind of product, if the staff in violation of operating procedures, should accept the corresponding warning education, but also have the effect of notice of others. How much the body with static electricity, and people wear different fabrics clothes, and each person's physique, autumn and winter night we take off clothes is very easy to see the discharge between the clothes, the voltage of this electrostatic discharge is three thousand volts.
Some enterprises to adopt manual welding, using 40-watt ordinary iron, the welding temperature control, solder iron temperature above 300-400 ℃, the welding of high temperature can cause death lamp, LED lead expansion coefficient at high temperature is higher than about 150 ℃ the expansion coefficient of the several times, internal gold solder will because of excessive heat bilges cold shrink the welding points and death light phenomenon.
In view of the above phenomenon,LED packaging manufacturers and LED lighting application manufacturers should develop a strict LED standard user manual, in the production process to prevent online phenomenon.