Proceedings PaperOptical efficiency of light valve projectors
|Format||Member Price||Non-Member Price|
Light-valve projectors are becoming increasingly popular for large screen displays. This is particularly true for high definition displays over 50' diagonal. In these applications light output of 1000 to 10,000 lumens is desirable. For consumer applications this is needed to overcome ambient light levels and for commercial applications it is needed for the longer screen sizes. Optical efficiency, contrast ratio and cost are the major problems for satisfying the requirements of these applications. These parameters are interrelated. Increased optical efficiency reduces the cost of the light source and its power. In many systems high contrast and light modulator heat dissipation require larger modulator areas which increases the cost of the light modulator and its associated optics. Several light modulator options will be discussed with these trade-offs in mind. These include active matrix LCD's, passive matrix LCD's, optically addressed LCD's, digital micromirror device projectors and light-valve projectors using liquid-crystal phase diffraction gratings. Many of these compromises can be alleviated if solid-state laser light sources can be used. Experiments on projectors using these light sources in all three primary colors will also be discussed. Since efficient solid-state laser sources are quite a recent experimental development, their current price is prohibitive. However, they should not be ruled out as an option if they can be manufactured in large quantities at a reasonable cost. Their use could greatly reduce the cost of the other components in the projector.