Measurements to resolve the outstanding issues of the current international standards for LED-based sources
Demonstrating product performance is important in the lighting market to maintain consumer confidence. For LED-based lights the necessary laboratory tests to assess this are detailed in international standards but currently there are no validated procedures for some of the required measurements. Existing photometers do not have an exact spectral match with LED sources and differences require correcting with the f1’ index, based on the spectrum of a filament lamp, resulting in inaccuracies in luminescence measurements. A new mismatch index for LED reference spectra requires development and its applicability for coloured LEDs determined.
The project will develop guidelines for producing validated, traceable measurements of luminance and luminous intensity distributions for LEDs. Guidance will be also developed detailing improved spectral measurements for white light using an alternative f1’ index. This will allow photometers designed for non-tungsten-filament lamps to be characterised and extending this method to coloured LED sources will be investigated. At the completion of the project in 2023 project outputs will feed directly into relevant standards, resulting in better comparability, and consumer confidence, for LED-based light sources.