Photometric characterization of extended sources by subsource goniospectroradiometry

Abstract

We have developed a complete procedure to reduce photometric near-field experimental data by characterizing the spectral and angular distribution of small areas of extended sources, or subsources. Once these subsources are photometrically characterized and expressions of the spectral radiance for all subsources are given, any photometric quantity of the complete source can be calculated by integration in a very modest lapse of time, which is a clear advantage with respect to ray-tracing methods for real-time visualization applications. The expressions of the spectral radiance for all subsources are also an important starting point to identify the relevant uncertainty sources in a near-field measurement. We have tested this procedure using the near-field goniospectroradiometer developed at IO-CSIC, which allows spectral, angular and spatial photometric measurement to be carried out. A set of OLEDs of different sizes, shapes and manufactures have been used as test sources. The results obtained by our procedure have been compared with those experimentally obtained by conventional far-field goniophotometry.