The light guide plate in LCD backlight has a large number of surfaces that make patterns. They make simulation time long in the non-sequential Monte Carlo ray tracing simulation. We present an efficient way to handle the printed pattern in light guide plate; we used the area ratio function of pattern as a probability function of meeting at the pattern surface. This reduced the calculation loops of simulation,and made the great improvement of simulation speed.We developed a simulation tool to apply our new algorithm,and compared the simulation result of our approximate ray tracing method with that of real tracing,and also compared the simulation speed of ours with that of commercial one.
A new synthetic evaluation method for the color display is studied. A testing system to measure the luminance, chromaticity, contrast ratio, uniformity, viewing angle as well as the PMTF (polychromatic modulation transfer function) is presented. The PMTF is calculated from the values of the monochromatic MTFs weighted by the CIE photopic luminous efficiency function of the human visual system. A high-precision XYZ translation stage to move the testing system and a two-axis goniometer to tip and turn the display under test to the desired viewing angle are used.
Two methods to measure the MTF (modulation transfer function) of an optical engine of CRT rear projection HDTV (high definition television) are introduced. A rotating image analyzer on the fluorescent surface with a 2D CCD and a relay lens is used to test in the full-field angle. We developed a software program to automatically locate and measure the position of the maximum value of the MTF at any spatial frequency.