Automatic measurement system for long term LED parameters

摘要

During the past years significantly increased the number of LED models available on the market. However, not all of them have parameters which allow for use in professional lighting systems. The article discusses the international standards which should be met by modern LEDs. Among them, one of the most important parameters is factor of luminous flux decline in value during the operation of the LEDs. Its value is influenced by many factors, among others, the junction temperature of the diode and average and maximum values of supply current. Other important, for lighting reasons, parameters are stability of correlated color temperature and stability of chromaticity coordinates of the emitted light. The paper presents a system to measure luminous flux and colorimetric parameters of LEDs. Measurement system also allows for measuring a change in these parameters during operation of the LED.