Dlp technology

Digital Light Processing Technology

It is information age. Computers, faxes, modems, pagers, and cellular phones surround us. All these products rely on digital technology. Digital cameras, digital camcorders, digital satellite systems and, digital video disk players are some of the more recent inventions. Most of these video displays make use of the old analog cathode ray tube, which converts the digital video and graphic data into analog, before it is viewed. Digital Light Processing is a new display technology that provides a completely digital video information structure.

Digital Light Processing technology uses an optical semiconductor to digitally manipulate light. Dr. Larry Hornbeck developed this revolutionary display solution at Texas Instruments in 1987. This technology is being used to deliver the best picture across a broad range of products such as large screen digital televisions, projectors for business, home, professional venues and digital cinema. Texas Instruments are the primary manufacturers of Dlp technology. Many licensees who market products based on Texas Instrument?s chipsets use this technology in their products.

Digital Light Processing projection system has microscopically small mirrors laid out in a matrix on an optical thumbnail size semiconductor light switch. This semiconductor is known as a Digital Micromirror Device or Dlp technology Chip. Each mirror represents one pixel in the projected image. Thus, the number of mirrors are responsible for the resolution of the projected image. These mirrors are mounted on a hinge structure so that it can be individually tilted back and forth, either towards the light source (on) or away from it (off). The mirrors are electronically tilted at speeds greater than 1,000 times per second. This results in varying the intensity of the light being reflected out through the lens, leading to shades of gray in addition to white and black. This technology can reflect pixels up to 1,024 shades of gray, converting the video or graphic signal into a highly detailed grayscale image.

Two primary methods by which Dlp technology projection system creates a color image are Single-Chip Digital Light Processing projection system and, Three-Chip Digital Light Processing projection system. Single Chip Digital Light Processing Projection System is used in televisions, home theater systems and business projectors. The process basically makes use of four main components, the Digital Micromirror Device that is also known as the Digital Light Processing chip, a color wheel, a light source, and optics. The color wheel is placed between the lamp and the Digital Micromirror Device. Light is produced by the lamp, which passes through the color wheel filter and further into the Digital Micromirror Device. This device switches its mirrors on or off in relation to the color reflecting through them, producing an image. The white light is thus, filtered into three primary colors: red, green, and blue; which are reflected through the optics. Projectors used for cinemas and large venue displays, which require very high image quality and brightness make use of the ?Three Chip Digital Light Processing projection system?, to produce stunning moving or still images. The difference with the Three Chip Digital Light Processing projection system is that, a prism is used to split light from the lamp, and each primary color is further routed through individual Digital Micromirror Device, then recombined and rerouted out through the lens. Single-Chip Digital Light Processing system can display 16.7 million (24-bit) colors, whereas Three-Chip Digital Light Processing system can display up to 35 trillion colors.

Advantages

Digital Light Processing technology results in brighter and effective presentations. The exact mirror image of an input video or graphic signal is produced, which results in sharper picture. The images produced are virtually seamless. The picture appears seamless because the mirrors have very tiny spaces between them, one-micrometer gaps, to be exact. Machines that use this technology are smaller and compact, for example Dlp technology projectors are small and light, making them versatile for use in conference rooms, living rooms and classrooms. They have a muted pixel structure when viewed from a typical viewing distance. The screen door effect is no more a problem. The viewer can see a seamless, digitally generated and projected image. Televisions using this technology are smaller, thinner, and lighter.

Digital Light Processing systems are inherently reliable. They are subjected to a series of environmental and regulatory tests to stimulate thermal shock, temperature, mechanical shock, vibration, moisture resistance, and acceleration conditions.

Also, since Digital Light Processing technology uses a mirror and light, the backlight bulb is replaceable. In certain machines, the Digital Light Processing is configured in such a way that even a layperson can easily replace the burned-out bulbs. This results in potentially longer life of the machine.

Weakness

The only weakness that can be pointed out with this technology is the Rainbow Effect, which is unique to the Single Chip Digital Light Processing projection system. Rainbow Effect can be defined as ?brief flashes of perceived red, blue, and green shadows?. Single Chip Digital Light Processing projection system makes use of a color wheel to produce colors. As a result, at any given instant of time, the image on the screen is either red, or green, or blue. Most of the time, human eye is not able to detect these rapid changes. However, sometimes when the eye moves across the projected image, these separate colors become visible, resulting in a perceived "rainbow". The rapid sequencing of color has also resulted in reported complaints of eyestrain and headaches amongst viewers.

In order to overcome this problem, Texas Instruments and the vendors who build projectors using Digital Light Processing technology have started using color wheels rotating at higher speeds, or with more color segments. Many Digital Light Processing projectors being built for the home theater market are incorporating a six-segment color wheel, which spins at the speed of 120 Hertz or 7200 rotations per minute. Although, the appearances of these artifacts have reduced amongst viewers, the problem still persists.

More and more information in today?s world is created, edited and transmitted in the digital domain. Majority of the already existing technologies limit the full potential of digital display. Digital Light Projection technology is the only digital projection solution available, which produces an entirely digital video infrastructure.