What Is a DLP Projector?

A DLP projector is a video projector that uses digital light processing to produce the projector. The DLP technology, which was created and is trademarked by Texas Instruments, uses millions of microscopic aluminum mirrors to reflect and project its video image. This is the same method used by TI's DLP high-definition TV sets as well as with digital cinema projection. DLP projectors mainly compete with LCD video projectors and are believed by many to produce a higher picture quality than other projectors.

Function

A DLP projector uses a semiconductor chip called a digital micromirror device or DLP chip, which contains a matrix of many extremely small aluminum mirrors (as many as two million). The chip is on the projector's DLP board with its processor. The DLP board receives the video signal, and the light from the projectors lamp reflects off of the mirrors (after passing through lenses and a color wheel or prism) and through the projection tube and lenses.

Types

DLP projectors can operate with a single DLP chip or three. A single chip projector mainly uses a color wheel that the lamp light is sent through before reflecting off the mirrors. The color wheel contains three to seven colors that the light passes through and then bounces off the same component on the chip. In a three chip projector, the light is split through a prism and the primary colors - red, green and blue - are each sent to their own chip for that color.

Manufacturers

Texas Instruments holds a trademark on the DLP technology but licenses it out to be used in projectors made by multiple manufacturers. Mitsubishi, Dell, ViewSonic and NEC are some of the manufacturers who use TI's DLP technology in their projectors. The projectors can vary in prices, with most ranging from hundreds to thousands of dollars.

SIze/Significance

As with their TV counterparts, the resolution of the projected image depends on the number of mirrors contained in the projector's DLP chip. The more mirrors the chip has, the greater the projector's resolution. The resolution can range from as small as 800 by 600 pixels to 1920 by 1080, with 1024 by 768 and 1280 by 720 in between.

Rainbow Effect

One problem older DLP projectors encountered was a "rainbow effect," which was when shadows of red, blue and green would briefly flash on the screen. This normally happened on a picture displaying white or very bright objects against a black or dark background. The ability to see a rainbow effect would differ from person to person - some could see it often, others not at all. Such rainbow effects almost never occur anymore as projectors are built with color wheels traveling at faster speeds.