Zemax Development Corp. publishes an optical design program for both sequential and nonsequential ray tracing. The software can be used to conceptualize, design, optimize, analyze, tolerance and document virtually any optical system. It also allows users to use diffraction calculations to propagate any arbitrary beam through an optical system. The image at right shows a screen capture of a fly's eye integrating system for a digital projector. The lamp output is circular, with a dark spot in the center. After imaging through a pair of lenslet arrays and a field lens, a uniform rectangular illumination patch is produced — ideal for illuminating DMD, LCD or LCoS devices. Zemax software is used by optical engineers and designers for lens design, backlighting, illumination optics, stray light, LED optics and many other applications.