The photometry of hollow light guides

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.Light-pipes described in this paper guide light along an axis allowing it to escape from its surface for illumination purposes. Light is coupled into them by a beamer luminaire. The performance of a hollow light guide very much depends on the quality of the materials used to guide the light. The luminous characteristics of these materials influence a light-pipe’s overall performance. The first section of this paper describes measurement techniques for light incidence resolved measurements on materials. Common co-ordinate systems for describing the geometry and a data format to store the data are shown. The second section of this paper deals with light-pipe goniophotometry. A goniophotometer for light-pipes has been constructed at the Technical University of Berlin. To evaluate the results measurements are compared to these from a real installation