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

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 Rthj-c was determined, thereby enabling the final junction temperature Tj 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 ηo for three selected LED sources from various manufacturers. The tests were conducted at three forward current values, IF = 350, 700, and 1050 mA, and four Peltier module temperatures, Tp = 25, 45, 65, and 85 °C. The obtained research results were analysed and conclusions were formulated.