Application of Wire-Grid Polarizers to Projection Displays

We have measured the optical properties of wire-grid polarizers (WGPs). The implications of these results to the application of WGPs in projectors that use reflective light valves are discussed. In particular, the brightness and the contrast ratio of the projection system are investigated as functions of the angle of incidence of the light beam onto the WGP. It was found that the optimal incident angle is dependent on the physical design of the wire grids. In the sample that we describe, the optimal incident angle was 35 ° instead of 45(degree). At the optimal incident angle, both the transmission and the reflection extinction ratios can be quite good. However, WGPs suffer from the drawback of free-carrier absorption by the metal grid.