25.2: Invited Paper: Dual Paraboloid Reflector Illumination System for Digital Cinema

Abstract

It has long been demonstrated that, besides extending the life time of UHP lamps, the Wavien patented dual paraboloid reflector (DPR) can also enhance the lamp brightness in the low etendue regime. As a follow-up to our previous work we examine the possibility of extending the same DPR advantages to xenon arc lamps used in digital cinema. With ray tracing, we calculate the throughput efficiencies of a standard compound elliptical reflector used in the industry and a DPR reflector of similar size at various etendue values. The resultant efficiency/etendue curves are plotted and it is shown that, at a typical etendue value of 50 mm 2 *steradian for digital cinema up to 100% brightness improvement can be achieved. Another unique feature of the DPR system is that light recycling can be realized through etendue reduction by a recycling light pipe. Up to 40% recycling gain has been demonstrated with a 1:4 input/output etendue ratio. In addition, it is expected that the lifetime xenon lamps with the DPR can also be extended.