4.3. Relationship between the LED current and irradiance on the
test plane
LED light outputs, and, subsequently, irradiance decrease with
increasing LED current, due to temperature rises. Only red and blue
arrays provide irradiance higher than 1000 Wm2 while less than
this irradiance value is available from green, white and RGB arrays.
LEDs become less efficient as their light outputs rapidly fall with
increasing current (Fig. 7).
To permit higher light outputs from the green, white and RGB
arrays, LED current should be increased without accompanying
large increase in temperature. This would be possible if chilled air,
instead of room temperature air, is used in the cooling. But this
would be complex and more expensive.