Some of the materials used may in fact be exotic in nature, particularly a dichroic reflector for the bulb. This coating will allow infra-red light (heat) to pass through while reflecting visible light, thereby reducing the amount of heat shooting through the LCD element (or at the DLP mirrors). Also, the reflector may not be a second-power parabolic rather a fourth-power parabolic which much more accurately and evenly distributes light rays emitted from a focal point, and are therefore more difficult to accurately manufacture.