4.1. Thermal characteristics of LED arrays
The five LED arrays are at first supplied with respective rated
voltages on a continuous basis for 300 s without forced cooling.
Infrared pictures of heat sinks at the rear of each LED array are then
taken.
subsequently, a pulse voltage signal, at 3e5 times respective LED rated voltages, having 10 ms pulse duration and 1 s period, is applied for 300 s. Infrared pictures are similarly taken.
Comparison is made on a normal picture and the two infrared pictures.
As an example, only results of the red array are shown, Fig. 5
In a continuous voltage operation, a marked temperature rise of
the heat sinks is clearly seen (63 C) in a continuous operation.
However, the array remains at roomtemperature (27 C) under pulse
operation. This demonstrates themerit of the pulse operation mode.