Semiconductor devices which emit optical radiation can be divided into two distinct groups, luminescent diodes, usually known as Light Emitting Diodes or LEDs, and laser diodes. The present repot is concerned only with the first group, conventional LEDs.
Laser diodes, like other types of lasers, emit radiation in a coherent, spatially narrow beam with quasi-monochromatic spectral characteristics. They require a completely different measurement technique to ordinary LEDs and are not dealt with in this report.
CIE 127-1997 history
2007CIE 127-2007 Measurement of LEDs (Second Edition)