Novel optics for high-performance digital projection systems and monitors: current and future

Recently, digital projection systems have evolved quickly in accordance with their important role in multimedia displays and the market demand for higher performance. The general trend has been, higher performance requires more bulky and expensive systems. There are several approaches for the projection and illumination optics to overcome this trend. Among these is the use of aspheric lenses. Normally a plastic aspheric lens fabricated by diamond turning is regarded only for use in prototypes. However, this can be adopted into high-end products by careful consideration of several critical issues. A dffractive/refractive hybrid lens is another possible choice due to recent technical breakthroughs overcoming the superfluous diffracted light that has confined this hybrid lens to several special applications despite many advantages to use this promising element. A possible design example for a projection lens with the hybrid elements is suggested. LED illumination is a novel approach for a projection monitor that can be successfully commercialized in the near future. Because of their superb properties of long lifetime, good color saturation and high efficiency LEDs are useful in this application. An optical system that can maximize LED illumination efficiency is suggested.