DLP (Digital Light Processing) is a technology widely used for projecting images from a monitor onto a large screen for presentation purposes. A DMD (Digital Micromirror Device) is used to create sharp images which can be clearly noticed even in a normally lit room. Developed in the 1980s by Texas Instruments (TI), DLP became commercially available in the late 1990s. Texas Instruments remain the sole manufacturer of DLP technology.

How DLP Works

Before the development of DLP, most computer projection systems were based on LCD technology which tends to generate blurry and faded images. DLP utilizes tiny mirrors housed on a unique kind of microchip known as a DMD (Digital Micromirror Device). A DMD is a memory chip covered with hinged, microscopic electromechanical mirrors, one for each pixel on the screen. The number of mirrors used in a DMD is equivalent to the resolution of the displayed image. 800×600, 1024×768, 1280×720, and 1920×1080 (HDTV) are some of the most common DMD sizes. The mirrors in a DMD can be quickly repositioned to reflect light through the lens or onto a heatsink. This is termed as a light dump.DLP (digital light proccessing)

Single-chip DLP Projectors

In a single chip DLP projector, colors are generated by a color wheel, which is placed between a lamp and the DMD. The color wheel is usually divided into four parts. The first three parts constitute the primary colors – red, green, and blue – and the last part is a clear section which helps to improve the brightness of the projected image and decrease color saturation.

The DMD chip is designed so that an observer can view the composite "full color" image clearly without any single color dominating the view. To accomplish this, the DMD chip is synchronized with the movement of color wheel so that the red component is visible on the DMD when the red section of the color wheel comes in front of the lamp. The same is the case with the blue and green sections. In early DMD models, the spin of the wheel was one rotation per frame. In never DLP designs, the wheel spins at double the frame rate.

Single-chip DLP systems can display up to 16.7 million colors.

Three-chip DLP Projectors

In three-chip DLP projector, a prism is utilized to divide light from the lamp, and each primary color of light is then diverted in to its own DMD chip. It is then recombined and projected out through the lens. Three-chip DLP systems are capable of displaying up to 35 trillion colors.

The Origin of DLP

The first DMD chip was invented by Larry Hornbeck in 1987. Larry, a scientist of TI, had been exploring the manipulation of reflected light since 1977. Texas Instruments started a project to explore the commercial viability of DMD. TI named the new technology DLP and a separate group (now known as the DLP Products division) was formed to develop the commercial display applications.

Texas Instruments demonstrated prototype DLP projectors for the first time in 1994. The new technology was quickly recognized and in 1997, DLP projectors were used to project films at the Oscars, where the first 3-chip DLP technology was revealed to the Hollywood community. DLP Cinema was first revealed to the public with the release of Star Wars Episode I: The Phantom Menace in 1999. And by the end of 2002, Texas Instruments had shipped over two millions DLP subsystems.

Advantages of DLP

  • The main advantage of DLP is that is can provide excellent picture quality.
  • The images are sharp and are not blurred or faded.
  • Bright images allow clear viewing even in a brightly lit room.
  • As DLP is semiconductor based, the chipsets are much lighter and compact than the conventional rear projection televisions.
  • Since DLP is based on a digital technology, DLP systems can provide consistent performance over their lifespan. On the other hand, analog sets ten to dim over a certain period of time.
  • Excellent contrast and color depth.

Disadvantages of DLP

  • DLP lamps have a short lifespan and must be replaced every 1,000 to 6,000 hours.
  • DLP sets have an inability to reproduce "true black" levels.
  • DLP sets are much more expensive than CRT based rear projection televisions.
  • Some people observe a "rainbow effect" in single chip DLP designs.

DLP has achieved a ten percent market share in the rear projection television market and over two million DLP systems have been sold.