CIE 148 PDF

CIE 148 – Measurement of LEDs

This report is an update of the previously published CIE Technical Report CIE 127-1997.There are significant differences between LEDs and other light sources whichmade it necessary for the CIE to introduce new quantities for their characterizationwith precisely defined measurement conditions. New quantities introduced here are”Averaged LED Intensity” and “Partial LED Flux”.

The report describes in detail the measurement conditions for ALI (AveragedLED Intensity), Total and Partial LED Flux and Spectral Power Distribution. It isshown that measurements by substitution method using LED standards can besimpler; however it is important to compare similar coloured LEDs or use colourcorrection on the measurement results. The standard LEDs need to be calibrated byNational Metrology Laboratories or a laboratory traceable to National MetrologyLaboratories.

The report is written in English, with a short summary in French and German.