Measurement of Solid-State-Lighting for Indoor Work Places
Constantly changing measurement environments
LED technologies, collectively referred to as solid-state-lighting (SSL), have revolutionised the field of general lighting creating exciting possibilities, but also bringing measurement challenges for manufacturers and installers alike. The development and manufacture of LED devices, LED lamps, and LED luminaires all require extensive testing and qualification. For this purpose, high-quality light measurement systems for spectral characterization are used, which provide precise measurement data. However, the planning and verification of SSL schemes also benefit from spectral and color measurement capabilities not offered by the lux meter products traditionally used for such purposes.
The European standard, EN 12464-1 [1], defines lighting requirements for indoor work areas.
The standard includes the following measurement criteria based on the intended use of the lighting:
- the minimum required average illuminance per task (referred to as “maintained illuminance”);
- the minimum required color rendering (specified as a minimum CIE Ra value).
Accurate Indoor Work Place Measurement System
The spectral distribution of SSL can be very different to that of traditional lighting technologies resulting in potentially significant errors in illuminance measurements made with filter-based lux meters. Determining the color rendering index requires the measurement of the spectral power distribution of the light. Therefore, both measurement requirements are best satisfied by light meters with full spectral measurement capability such as the MSC15 versatile spectral lux meter which eliminate the spectral mismatch errors of lux meters and yield full colorimetric data. The BTS256-EF spectral light meter optimized as mobile transportalbe meter, for example, also permits the assessment of light flicker and stroboscopic effects.
References
[1] EN 12464-1:2011 Light and lighting. Lighting of work places. Indoor work places.