High-Power LED Chip-on-Board Packages with Diamond-Like Carbon Heat-Spreading Layers

The thermal properties of a flip-chip light-emitting diode (FCLED) chip-on-board (COB) with diamond-like carbon (DLC) heat-spreading layers are investigated. The temperature-dependent performance of the COB packages with and without DLC heat-spreading layers at the LED and metal core printed circuit board sites are studied. Results show that the device junction temperature and thermal conductivity of the COB package with DLC heat-spreading layers (DLC package) are less than those of the COB package without DLC heat-spreading layers (regular package). For the steady state of light intensity, the mean of light intensity drop for 12 tested packages of DLC package was improved by 6.1% after 3 hours of burn-in compared with that of the regular package.