| 摘要 |
PROBLEM TO BE SOLVED: To provide a simplified and quantitative deterioration diagnostic method, capable of being performed during product operation and using electrical characteristics.SOLUTION: A life diagnostic method for a semiconductor light emitting element includes: steps S1, S2 of preparing a plurality of semiconductor light emitting elements as objects of life diagnosis to be classified into a plurality of groups; a step S3 of performing an acceleration test to the semiconductor light emitting elements classified into the groups at a temperature higher than that in a real operational environment and different for each group; a step S4 of acquiring characteristics of optical amount change and junction temperature change (&Dgr;Tj) for the semiconductor light emitting elements after the acceleration test; a step S5 of deriving a regression expression of an approximation straight line from the correlation between optical amount change and &Dgr;Tj; a step S6 of calculating a threshold of &Dgr;Tj corresponding to the optical amount change, from the regression expression; and steps S7, S8 of measuring &Dgr;Tj for semiconductor light emitting elements during actual operation and diagnosing the surplus life of the semiconductor light emitting elements from the relation between the &Dgr;Tj and the threshold. |
