The Science Behind DLP Television
by: Mitchell Medford
DLP televisions are based on a technology invented by
Texas Instruments back in 1987 called Digital Light
Processing. The technology is based on an optical
semiconductor called DMD (Digital Micromirror Device)
chip. It is a highly reliable, all-digital display chip
that delivers the best picture across a broad range of
products, including large screen digital TVs, and
projectors for business, home, professional venue and
The chip consists of over one million mirrors to
process light. They come in either single chip or 3 chip
configurations. One-chip DLP systems use a projection
lamp to pass white light through a color wheel that
sends red-green-blue colors to the DMD chip in a
sequential order to create an image on-screen. Only one
DMD chip is used to process the primary RGB colors.
Three-chip DLP systems use a projection lamp to send
white light through a prism, which creates separate red,
green, and blue light beams. Each beam is sent to their
respective red, green, and blue DMD chip to process the
image for display on-screen. One-chip models are said to
produce a display of over 16-million colors. Three-chip
models can produce a display of over 35-trillion colors.
The result is maximum fidelity: a picture whose clarity,
brilliance and color must be seen to be believed.
When a DLP chip is coordinated with a digital video
or graphic signal, a light source, and a projection
lens, its mirrors can reflect an all-digital image onto
a screen or other surface. The DLP chip and the
sophisticated electronics that surround it are what we
call Digital Light Processing™ technology.
Benefits of Single chip DLP:
1. Fantastic color accuracy.
2. The best contrast ratios and shadow detail.
3. Generally very quiet.
4. Very little space between each pixel creates a
very smooth image, even when using lower resolution
5. Light engine failures are very rare so repairs are
less costly than other technologies.
6. Technology doesn't degrade over time. With proper
routine maintenance, DLP™ projectors consistently
provide just-out-of-the-box performance. (DLP™ is the
only technology that makes this claim).
Benefits of Three chip DLP:
1. Good contrast; much greater than film theaters.
2. Good shadow detail.
3. Can provide high brightness compared to the
limited brightness of single chip versions.
4. Overall image quality deemed as the best of any
type of micro display technology.
5. Same technology as projectors installed in digital
6. Pure digital technology.
The bit-streamed image code entering the
semiconductor directs each mirror to switch on and off
up to several thousand times per second. When a mirror
is switched on more frequently than off, it reflects a
light gray pixel; a mirror that's switched off more
frequently reflects a darker gray pixel. In this way,
the mirrors in a DLP projection system can reflect
pixels in up to 1,024 shades of gray to convert the
video or graphic signal entering the DLP chip into a
highly detailed grayscale image.
The white light generated by the lamp in a DLP
projection system passes through a color wheel as it
travels to the surface of the DLP chip. The color wheel
filters the light into red, green, and blue, from which
a single-chip DLP projection system can create at least
16.7 million colors. And the 3-chip system found in DLP
Cinema™ projection systems is capable of producing no
fewer than 35 trillion colors. The on and off states of
each micromirror are coordinated with these three basic
building blocks of color. For example, a mirror
responsible for projecting a purple pixel will only
reflect red and blue light to the projection surface;
our eyes then blend these rapidly alternating flashes to
see the intended hue in a projected image.
|About The Author
Mitchell Medford is an author and product consultant for several
consumer electronics manufacturers. Visit his
website for more information on home theater, LCD
TVs, and plasma televisions: