Rear Projection: DLP
DLP (digital light processing) projectors work by manipulating thousands of tiny mirrors on a semiconductor chip. Color is generated by shining a light through a rotating color wheel that has red, green, and blue on it. The now colored beam hits the semiconductor chip to create the image used for projection.
Front Projection: DLP
DLP projectors are just like their rear-projecting brothers. DLP projectors use scads of tiny mirrors to reflect an image onto the screen.
Photo courtesy Newstream
A digital projector from Sharp