Junction Temperature Governs Flux, Color, and Lifetime
LED performance is a thermal specification as much as an optical one. Junction temperature drives luminous flux output, chromaticity shift, and the lumen-maintenance curve that a lighting warranty is built on.
Why thermal decides the outcome here
The same LED die produces measurably different flux and color point depending on how well the thermal path from junction to board to luminaire body is designed. Get the thermal resistance chain wrong and the fixture ships compliant on paper but drifts in color and output in the field.
- Junction temperature vs. luminous flux and chromaticity shift
- Junction-to-board thermal resistance (Rth_JB)
- PCB spreading resistance under dense LED arrays
- Luminaire body convection in enclosed fixture designs
- LED array cross-talk and mutual heating
- Lumen-maintenance and warranty lifetime prediction
- Die-to-board conduction and Rth_JB
- PCB copper spreading under concentrated LED arrays
- Natural and forced convection in luminaire housings
- Array-level thermal cross-talk between adjacent emitters
- LM-80 (lumen maintenance testing)
- TM-21 (lifetime projection from LM-80 data)
- LM-84 (luminaire-level lumen maintenance)
- AEC-Q102 (automotive LED qualification)
- JEDEC JESD51-51 / JESD51-52 (LED thermal test conditions)
Simulation shows the design. Measurement proves it.
Paid engineering engagements for this industry.
- 01
LM-80 / TM-21 aligned junction temperature measurement
- 02
Luminaire thermal design and array cross-talk analysis in FLOEFD
- 03
Power cycling for lumen-maintenance and warranty support data
Related workflows
Design the luminaire against measured junction temperature, not a datasheet assumption.
Talk to a thermal specialist about LM-80/TM-21 aligned thermal characterization for your fixture.
Talk to a Thermal Specialist →