Abstract:
A versatile system has been developed for the measurement under LABVIEW™ control of junction
temperatures in a light emitting diode (LED). Measurements are reported on a commercially
available high-intensity InGaAlP LED immersed in liquid nitrogen and driven by currents in the
range of 18.5–204 mA. The measured junction temperature has an expanded uncertainty of ±2 K at
the 95% level of confidence for temperatures from 70 to 298 K. Using the measured junction
temperatures, the junction-to-case thermal resistance of the LED was established as 440 K/W for
devices with intact encapsulation and 307 K/W for partial encapsulation
