CRT (cathode ray tube) projector. This typically involves a red, green, and blue tube. This is the oldest system still in regular use, but losing ground quickly because of the huge cabinet involved. However, it does provide the largest screen size for the dollar. This also includes three tube home models, which, while quite large, can be moved but require precise picture adjustment to get the three images to line up perfectly.
LCD projector using LCD light gates. This is the simplest system, and one of the most common and affordable for home theaters and office use. Its most common problem is a visible pixelation problem, although recent advances have come to reduce this.
DLP projector using Texas Instruments’ DLP technology. This uses one - three micro light valves called digital micromirror devices (DMDs). The single- and double-DMD versions use rotating color wheels in sync with the mirror refreshes to create color. The most common problem with the single- or two-DMD varieties is a visible rainbow effect which some people see when moving their eyes. I have noticed this comment on more then one modern DLP style projector which uses color wheels. More recent projectors with higher speed and optimised color wheels have reduced this artifact. Systems with 3 DMDs never had this issue, as they show each primary color simultaneously. These are not common to find for home use.
