Research on thermal resistance Rthⱼ₋꜀ to determine the junction temperature and its impact on selected light parameters of high-power LED sources

Abstract

The article examines the impact of temperature on the main lighting parameters of selected high-power LED sources. In the first stage of the research, the actual value of thermal resistance Rth_j-c was determined, thereby enabling the final junction temperature T_j of the tested LED sources to be determined. Then, using a laboratory setup with a 50 cm integrating sphere and a Peltier module, the research examined the effect of temperature on the luminous flux Φ, correlated colour temperature (CCT), colour rendering index (CRI), spectral distribution, and optical efficiency η_o for three selected LED sources from various manufacturers. The tests were conducted at three forward current values, I_F = 350, 700, and 1050 mA, and four Peltier module temperatures, T_p = 25, 45, 65, and 85 °C. The obtained research results were analysed and conclusions were formulated.