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将功率循环方法应用于大功率LED焊料层的可靠性研究,对比分析了在650mA,675mA和700mA电流条件下大功率LED焊料层的热阻退化情况。实验结果表明,循环达到一定次数,大功率LED热阻才开始退化,并呈线性增加,从而引起光通量下降;另外,失效循环次数与电流值之间呈线性关系,并外推出正常工作条件下焊料层寿命为90 968次。对样品进行了超声波检测(C-SAM),发现老化后LED焊料层有空洞形成,这说明空洞是引起热阻升高的主要原因。
The power cycling method is applied to the reliability research of high power LED solder layers. The thermal resistance degradation of high power LED solder layers under the conditions of 650mA, 675mA and 700mA is compared. Experimental results show that the number of cycles reaches a certain number of high-power LED thermal resistance began to degenerate, and showed a linear increase, resulting in decreased luminous flux; In addition, the failure cycle number and the current value of a linear relationship between the extrapolation and under normal operating conditions solder Layer life of 90 968 times. Ultrasonic testing (C-SAM) was performed on the samples, and it was found that there was a cavity formed in the LED solder layer after aging. This shows that the cavity is the main reason for the increase of thermal resistance.