To simplify the judgment of thermocouple measurement accu-
racy, we measured the air temperature above a bare LED chip pack-
aged on the leadframe. The measurement system is shown in Fig. 1.
As shown in the figure, a bare LED chip was mounted on a lead-
frame, and no phosphor layer or silicone was coated on the chip.
A K-style thermocouple was vertically hanged above the center
of the chip, and materials for each thermocouple wires are alumel
and chromel, respectively. The diameter of the thermocouple wire
and bead are 0.3 mm and 0.5 mm respectively. The distance be-
tween the top surface of LED chip and the thermocouple bead
was about 0.8 mm. The measurement system, including the ther-
mocouple and the LED module, was placed in a close glass box to
avoid the disturbance from surrounding.