DLP (Digital Light Projection)

DLP, or Digital Light Projection, is one of the most common types of projector technologies. Texas Instruments owns the patents on DLP, and manufactures the chips and imaging systems that most DLP projectors use. Companies buy assembled imaging units, or just the DLP chips, from Texas Instruments and install them in their own bodies.

In most home and office-use models, DLPs have a single chip inside covered with thousands or millions of microscopic mirrors (depending on resolution). There’s a mirror for each pixel. Positioned in between the chip and the bulb is a color wheel that spins at high speed, composed of filters for red, green, blue – and sometimes white or other colors. The mirrors on the chip flip on and off with extreme rapidity, bouncing light towards the lens or away into a light trap.

The color wheel is the key to both the strength and the weaknesses of DLP technology. By adding one or more white filters to the color wheel, a DLP projector can greatly increase its brightness levels. This is great for business and education projectors, where the lights are on in the room and the colors tend to be relatively simple. But the addition of white filters tends to wash out color saturation, which can make for unacceptable home theater performance. Sometimes, the user has control over which filters are active, increasing the versatility of the projector.

Many DLP projects now feature a technology called BrilliantColor, which adds additional color filters – usually cyan, magenta, and yellow – to the red, green, blue, and white filters. While Brilliant Color does increase the sheer number of possible color tones, it can create problems with smooth color transitions, which are crucial to home theater performance. As a result, you may choose to turn BrilliantColor on for a Power Point presentation, but turn it off to watch a movie.

Higher-end DLPs, like those used in theaters, have three chips, one for each of the red, green, and blue channel, thus increasing color faithfulness. However, the prohibitive cost of the technology makes it unlikely that you’ll have one in your home.

Because the DLP imaging system can be encased in an air-tight seal, there is no issue with dust build-up. By comparison, LCD projectors can be susceptible to dust infiltration and may require cleaning or he addition of filters that have to be changed. DLP advocates argue that this decreases the lower maintenance costs. However, LCD projectors require a less powerful bulb in order to get the same amount of brightness as a DLP in home theater applications (not using white filters), which reduces power consumption costs and generates less heat.