Digital Light Processing

An Introduction To DLP Video Projection Technology

By:Robert Silva

Big Screen TV is more popular than ever. The days of those projection sets that took up half the living room with their, bulky cabinets, only viewable in total darkness, with everyone crowded around the center of the screen, and high prices are gone. Today's big screen TV's are brighter, slimmer, viewable from the same angles as their Tube counterparts, and with prices for entry-level sets in the $1,500 and less, they have become more affordable than ever.

Current Projection TV Technology

Up until recently, big screen projection sets basically came in two flavors: CRT-based and LCD-based. The more economical sets are rear-projection types in which the CRT or LCD generated image are placed inside a "box", reflected off of a mirror and projected onto a screen. Another type of projection TV consists of a CRT-based or LCD-based projector that is mounted on a ceiling or placed on a table and projected onto a wall-mounted screen. These systems allow for larger images, but can suffer from dimness in lower-end systems. Generally speaking the "box" system is less expensive for the consumer, while the separate projector-screen systems are reserved for high-end home theater systems in which an entire room is devoted for viewing films or TV programs.

Athough CRT and LCD technology have improved over the years and the sets are more viewable and affordable, the picture contrast levels are still lacking, when compared to the traditional direct-view Tube Television.

In the last few years however, PLASMA screens have entered the market as an alternative to both projection and tube TV, and although very expensive, are making their way into more homes. The main attraction of PLASMA screen sets is the fact they are flat enough to be wall mounted, thus eliminating the need for that "box" or separate projector.

Plasma screens are an improvement. They are bright, have acceptable contrast levels, practical as both TV or computer monitors, and can be hung on the wall. Two drawbacks: despite their flexibility in use, they are extremely expensive to manufacture, are delicate to transport (shipping).

Enter Digital Light Processing

A new technology has arrived on the scene that may change the whole big screen TV concept forever: .

The key to DLP is the DMD (Digital Micro-mirror Device). In essence, every pixel on a DLP chip is a reflective mirror, which amplifies the light generated from the chip. Since the light generated by each pixel has its own amplification ability, there is no limit to the size of the screen that can be manufactured. Brightness and contrast is even across the entire surface of the screen.

The advantage of DLP is two-fold: (1) It produces bright, high-contrast images, viewable from a wide angle, and (2) It can be projected onto any size screen (from home theater setups to movie theater setups), with equal image quality.

With the advent of HDTV, DLP is the best option for reproducing high-resolution projected images.

On the industrial front, DLP is being used in large projection screen applications such as concert venues and movie theaters. Several films have been released to special take advantage of DLP projection technology, including: Star Wars: Episode I, Mission To Mars, Toy Story 2, Rocky and Bullwinkle, Disney's Dinosaur, and Spy Kids. This technology is indeed sufficient as an eventual replacement for standard film projection. DLP provides a large projected image with significant brightness and enough contrast (although film is still better at this point, especially with text detail).

If you would like to see a movie projected in DLP, check your local movie listings for an announcement, it is worth the experience.

With regards to home theater applications, several manufacturers, such as Hitachi, Panasonic, Samsung, and Mitsubishi are producing rear-projection DLP sets for the consumer. Although these sets are initially expensive, they are on par with current Plasma screen prices. As acceptance grows, prices will decrease.

Also, for those who favor front projection systems, several manufacturers, such as Mitsubishi Optoma, Runco, Marantz, and Dreamvision make units suitable for both home theater and business applications.


DLP is not without its competitors for both consumer and theatrical projection systems. JVC has been pushing its own system, dubbed D-ILA (Direct-Drive Image Light Amplifier) or H-DILA, into the marketplace. At CES, JVC demonstrates an impressive D-ILA projection system in conjunction with its D-VHS VCR. The results were at least as good as the DLP demos I have seen.

While DLP takes a unique approach, JVC's D-ILA system is based on LCD technology. In D-ILA light is reflected off a mirror surface located under the LCD pixel layer. In current LCD technology light is passed through the pixel layer. The reflective process results in higher brightness/contrast levels that allow images to be viewed easily in a lighted room. In addition, unlike DLP, which uses actual moving mirrors, there are no mechanical parts in the D-ILA chips.

JVC is making D-ILA systems available in both front and rear projection versions for both home and industrial use. However, with DLP ahead of the game with more manufacturing partners and more marketing muscle, it remains to be seen if D-ILA will become an affordable alternative to DLP.


CRT and LCD projection systems have been the mainstay in big screen and projection TV applications in both consumer and industrial settings for quite some time. While CRT-based projection systems have improved over the years and are currently serving well in various settings, DLP technology, with its compactness, increased brightness and contrast may, over time, replace CRT projection as the dominant form of big-screen projection technology. However, improvements in technology and lower manufacturing costs have placed LCD video projection in a tight race with DLP in terms of image quality.