A projection system typically includes a light source, illumination optics, one or more imagers, projection optics, and a projection screen. The illumination optics collect light from the light source and direct that light in a predetermined manner to the imager(s). The imager(s) are typically polarization-rotating, image-forming devices, such as liquid crystal display imagers, which operate by rotating the polarization of the light to produce an image corresponding to digital video signals. The projection optics then magnify the image and project it onto the projection screen.
Imagers used in projection systems typically rely on polarizers to separate light into a pair of orthogonal polarization states (e.g., s-polarization and p-polarization). The separation generally involves transmitting light having a desired polarization state and absorbing the majority of the light having an undesired polarization state. Such polarizers, however, absorb a substantial amount of light energy, which is converted to heat. During extended periods of use, the generated heat may build up and damage the polarizers, thereby diminishing the polarization properties. This accordingly reduces the quality of the projected images over time. Typically, high-speed air flows are provided over the polarizers to maintain the polarizer temperatures below acceptable limits. However, the required volumetric flow rates may be high, and the size and number of fans needed in the projection system can consume a significant amount of electrical power and space in the projection system, in addition to generating distracting noise.