Analysis of degradation effects on LEDs according to the production processes

More and more Light Emitting Diodes (LEDs) become more important in lightening system, for instance in cars, street lights, flashlights and individual lightening solutions. With the increasing use of LEDs an effect becomes visible: after short operating times some LEDs lose their brightness or become ohmic. What is the reason for this effect? How does the production process influence the appearance of this effect and how do we investigate the aging of LEDs? These questions will be discussed in this paper.