Spectral Ray Tracing From Near Field Goniophotometer Measurements

RadiantZemax,KXOptoelectronics

ABSTRACT

Measuredlightsourcemodelshavebeenwidelyusedinraytracesimulationsforopticaldesignformorethan15yearsnow, but to date the generated ray sets have not contained spectralinformation. In some limitedcases,tristimulusmeasurements can be helpful, but most ray tracing software requires a specificwavelength assignedtoeachraytoenablefullcolorsimulationsofanopticalsystem.

Thispaper describes and tests various techniques for combining spectralmeasurements with either photopicortristimulusimagingcolorimeterstoproduceraysetsthatcontainawavelength.Theseraysetscangenerallybereadilyusedbymostray-tracingsoftwaretomoreaccuratelyrefractanddiffractraysthroughtheopticalsystemandtogenerateilluminanceorluminancedistributionsthatalsoincludecolorimetricinformation.

Finallythemethodsaretestedwithreallightsourceswherespectralpowerdistributionvariessignificantlyspatiallyacrossthelightsourceand/orasafunctionofangle.

Keywords: (nearfield, goniophotometry, spectral measurement, white LED, source model, sourceimaginggoniometer)