Methods to measure the radiant flux of light-emitting diodes

Abstract

To measure the radiant flux of light-emitting diodes, sphere integration, goniophotometric, and pulsed methods have been considered. A convenient method to calculate the radiant flux using the indicatrix of radiant intensity and an integrating sphere design to measure the total radiant flux of light-emitting diodes with a wide angular distribution of radiation have been proposed. Moreover, the calibration of measurement equipment has been considered. The proposed methods and measurement tools help enable the measurement of the radiant flux of light-emitting diodes in the range of 1 mW to tens of watts. The measurement results are compared using different methods. A method to estimate the absolute measurement error is proposed.