星上定标光源LED长期工作的稳定性

为配合空间相机研制任务,对LED作为星上定标光源的可行性进行了研究。介绍了试验用LED的结构。从理论上分析了深能级的产生对LED发光效率的影响,引入阿仑尼斯模型对LED的衰减进行了分析。根据任务需要,对LED进行了老化试验,利用积分球法测量LED的相对发光强度,定时监测,得到LED发光强度随时间变化的曲线及趋势。根据试验结果,研究和分析了LED长时间工作的稳定性。试验结果显示,老化初期LED相对发光强度变化明显,经过250h的持续工作后,变化趋于平稳。3000h后LED相对发光强度总的衰减量约为3%,期间峰值变化量小于1.5%,满足星上定标的要求。给出了试验过程中LED的衰减情况,作为校正参考。最后根据实验结果对LED的寿命进行了理论的估算。

The Long Term Working Stability of Spaceborne Calibration LED Light Source

In order to serving the space camera developing mission,it is necessary to study the feasibility of using LEDs as spaceborne calibration light sources.Structures of LEDs are introduced.The effects of deep level on LEDs' radiant efficiencies are theoretically analyzed.The LED's degradations with time are studied using Arrhenius model.In order to obtain the long hours working stability of LEDs,we designed an aging experiment for LEDs,Using Integrating Sphere to measured the Relative Radiant Intensity (RRI) of LEDs regularly.Then,the trends and the LEDs RRI curves via time are studied.Experimental results show that the LED RRI changes significantly during early aging.After 250 h continuous test,changes become stable.The total radiant attenuation of the relative intensity is less than 3% after 3 000 h aging and the changes of peak- value are less than 1.5%.The results agree with the requirement of spaceborne calibration.As a calibration reference,the LEDs' radiant degradation are given.Finally,we estimate the life of LEDs theoretically.