The effects of cavity on the etendue of a light source

摘要

The simulation proposes that the cylindrical cavity around a circular lightsource can decreases the divergence angle without changing the emission energyand source size. This result can provide a way to reduce the etendue of thelight source by scrambling the rays inside the cavity with a losslessscattering surface. The experiment demonstrates that the metallic cavity aroundthe surface source reduces the divergence angle. However, the metallic surfacealso absorbs quite a large portion of the light energy. The Lambertian natureof the sidewall surface changes the directions of the rays into horizontaldirections. It increases the number of reflection inside the cavity andamplifies the small amount of absorption at a single reflection. The effect ofthe cavity on the etendue of the light source can contributes to providing moredesign flexibility in various lighting applications.