Case 2172 ยท Public preview
An LED Can Test Open Externally while Its Die Remains Functional
A failed infrared LED measured hard open at more than 300 megohms, but its die later showed a forward voltage within the reported specification.
Electrical testingOptical microscopyProgressive microsectioningBSE SEMInterface measurement
What the evidence preview establishes
The electrical open was localized to a bond wire fractured at a kink just above the die ball bond. Encapsulant separation and displacement supported mechanical loading of that weak point, with thermal overstress considered the likely driving event.
Why this case matters
When an LED is externally open, test the die separately and follow the entire interconnect path. Relate wire fracture location to encapsulant displacement and interface adhesion before concluding that the die itself failed.
Full evidence reserved for MEMBER and STOREThe complete case includes the evidence sequence, 4 interpreted figures, alternative explanations, limitations, and practical application guidance.