Fabrication and operation of an energy-harvesting color projector

Abstract

We have fabricated a 50mm x 50mm x 10mm waveguide that contained an array of stripe-shaped luminescent materials for three primary colors. By exciting these stripes with a modulated blue laser light, color images are displayed. Solar cells attached to its edge surface generate electric power by collecting photoluminescence photons not utilized for displaying images. The first device recovers only a very small fraction of the incoming optical power (about 1/4000) because the photons are scattered and lost during wave-guiding. This fraction would approach the theoretical limit of 0.75 by eliminating the scattering event.