Liquid crystal display projection system using multilayer optical film polarizers

摘要

A liquid crystal display (LCD) projection system including a projection panel, a light source, and a reflector. The projection panel includes an LCD and a polarizer on one side of the LCD and a reflective polarizer on the other side. The reflective polarizer is a multilayer stack of pairs of adjacent material layers. Each of the layer pairs exhibits a refractive index difference between the adjacent layers in a first direction in the plane of the reflective polarizer and exhibits essentially no refractive index difference between adjacent layers in a second direction in the plane of the reflective polarizer and orthogonal to the first direction. A quarter-wave plate is secured to the reflective polarizer. Light rays from the light source either pass through the reflective polarizer, and on to the LCD, or are reflected back toward the light source, depending on their polarization. Light which is reflected by the reflective polarizer is reflected by the reflector back toward the LCD again. The use of the quarter-wave plate and the reflector help to recycle what would typically be regarded as wasted light, while at the same time reducing heat build-up within the LCD.