LED - Colour point shift



LEDs are subject to colour point shift over the entire usable service life. XAL only uses LEDs for its luminaires, which have a minimal colour point shift in the test reports. LEDs with values of only 0.5 SDCM after 6000 h at 85 °C correspond to the highest quality (see graph 1 for SAMSUNG and graph 2 for OSRAM). The European PremiumLightPro requirement and the American EnergyStar requirement recommend the use of LEDs with a maximum colour point shift of ≤7 SDCM after 6,000 h. To keep the colour point shift as low as possible over the entire service life of 50,000 h, requires a great deal of invested expertise in thermal management. A power supply, which is within the specification of the LED, contributes just as much to a small shift in colour point as a good heat sink. Operating temperatures can thus be kept around 65 °C and the colour point shift can be limited to 1 SDCM after 10,000 h. The colour homogeneity at the end of the lifetime (final) is composed of the initial value (initial) of the colour point binning and the colour point shift. A data sheet specification with a final colour homogeneity is a mark of quality. A lack of such a specification is indicative of questionable quality. Example of a luminaire with a comprehensive colour point description: Initial ≤3 SDCM, directly on the BBL Final ≤4 SDCM after 10,000 h