Case 1527 ยท Public preview
Residual Lead Stress and Lens Creep Can Displace an LED Post During Reflow
Three switch-mounted LEDs became open-circuited after temperature exposure even though external examination revealed no obvious anomaly.
Electrical continuity testingOptical microscopyProgressive microsectioningBackscattered-electron SEMFailed-device comparison
What the evidence preview establishes
The LEDs failed because their internal posts displaced and ruptured the bond wires. The most likely driver was creep of softened lens material acting on residual lead stress introduced during the crimping operation.
Why this case matters
For an LED open that appears after reflow, section through the post as well as the die bond. A displaced post and gap in the lens can reveal package-scale movement that ruptures an otherwise intact wire connection.
Full evidence reserved for MEMBER and STOREThe complete case includes the evidence sequence, four interpreted figures, alternative explanations, limitations, and practical application guidance.