An approach of LED lamp system lifetime prediction

Different from the MTTF/MTBF widely used to describe the reliability of electronic products, lifetime is used for the LED lamp. The lifetime is defined as a time when 50% of lamp's lumen output is less than 70% of initial value, either by lumen decay of LED light source or catastrophic failure of electronic component. In other words, the reliability of LED lamp consists of not only the MTTF/MTBF of electronic components, but also other failure modes in the whole lifetime, ie electronic component or lumen degradation. However, the currently available reliability standards for LED lamp only focus on lumen maintenance, while cannot give any method on how to measure the LED lamps' lifetime. With reviewing the system structure and failure modes of LED lamp, the paper proposes a methodology for the reliability of LED lamp.