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Measurements to resolve the outstanding issues of the current international standards for LED-based sources

The project

Light Emitting Diode (LED)-based lighting products are the most rapidly evolving light sources on the market for general lighting in urban areas or domestic dwellings. Due to spectral and geometrical peculiarities, International System of Units (the SI) traceable measurements of LED-based light sources are much more difficult than those of traditional tungsten filament lamps or fluorescent light sources. This makes it difficult for test laboratories to evaluate application-relevant properties using existing measurement methods and standards developed for incandescent light sources. Standards for traceable test methods exist but important metrological aspects for their practical application have not yet been fully considered.

EMPIR project Revision and extension of standards for test methods for LED lamps, luminaires and modules (RevStdLED, 19NRM02) is working to develop guidelines for producing validated, traceable measurements of luminance and luminous intensity distributions for LEDs. At the completion of the project in 2023, project outputs will have been feed directly into relevant standards from CIE, ISO and CEN, resulting in better comparability, and consumer confidence, for LED-based light sources.

Input to technical standards

In order to enable project results to feed into relevant standards, the consortium has formed links with the relevant technical committees. The International Commission on Illumination (CIE) is devoted to worldwide cooperation and the exchange of information on all matters relating to the science and art of light and lighting, colour and vision, photobiology and image technology.

Project Coordinator Armin Sperling from PTB, Germany’s National Measurement Institute, is chair of the new CIE technical committee TC 2-96 ‘Revision of ISO/CIE 19476:2014 Characterisation of the performance of illuminance meters and luminance meters’. In addition, the technical committee includes six members of the project consortia. In this way, the research and results carried out within the project can be discussed directly within the TC with other international TC members from all over the world. Also the ‘Revision of CIE S 025:2014 Test Methods for LED Lamps, LED Luminaires and LED Modules’ which is identical to the European Standard EN 13032-4 will start very soon and will be chaired by a member of the project consortia.

Members of the consortium are also involved in the following CIE technical committees:

• CIE TC2-93 Revision of ISO 23539:2005(E) / CIE S 010/E:2004 Photometry - The CIE system of physical photometry
• CIE TC2-90 LED Reference Spectrum for Photometer Calibration
• CIE TC2-95 Measurement of Obtrusive Light and Sky Glow
• CIE TC2-62 Imaging photometer-based near-field goniophotometry
• CIE TC2-86 Glare Measurement by Imaging Luminance Measurement Device

Project Coordinator Armin said

‘19NRM02 RevStdLED will fill current gaps in photometry standards and provide missing guidelines for test laboratories to use measurement technology for LED-based light sources in a traceable way to meet the requirements of modern standards. The aim is that the specification of measurement uncertainties in test results can provide added value for both manufacturers and users.’

This EMPIR project is co-funded by the European Union's Horizon 2020 research and innovation programme and the EMPIR Participating States.

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