Lumen Maintenance
The removal of the intermediate substrate in COB packages allows heat generated at the LED junction to be transferred to a heat sink via the shortest possible thermal path. The absence of lead frames and plastic housings means COB LEDs do not have to struggle with lumen depreciation factors such as discoloration and yellowing. Lumen maintenance failures in COB LEDs occur typically due to inefficient or inadequate system-level thermal management. The high die density COB LEDs produce a substantial amount of heat which, if allowed to accumulate de proceless, will accelerate the gas and result in a permanent reduction in light output. This degradation can be exacerbated by the presence of moisture and pollutants as the gas/humidity permeability of silicone polymers increases at higher temperature. Entrapped moisture and volatile organic compound (VOC) in the encapsulation The conversion efficiency of silicone/YAG phosphor composites.
