Light recycling for light-valve-projection with sparkling video

In recent years, several architectures have been proposed for projection systems with an improved light efficiency by means of color recycling and/or polarization recycling. The recycling of light takes place in a rod integrator where light is coupled in from the lamp through a small hole in an entrance mirror. At the exit of the integrator, light of the wrong polarization state and/or wrong color is reflected back such that, after a round trip in the integrator, the light has a second chance of passing through the exit with a different polarization state or through a different color filter. Besides for recycling light of the wrong color or polarization, the integrator may also be used for recycling the unused light of pixels that are in a dark state. This allows for an increased brightness of bright parts in a dark scene, the so-called sparkling effect known from CRTs. We analyze the combined effects of color, polarization, and dark pixel recycling, extending the models previously proposed by Duelli et al. and by Zwanenburg.