Gas plasma technology is a new way to build
video and computer monitors. Essentially plasma units have the brightness
and look of a CRT monitor, but they offer a much larger image and are thin
and light enough for any application. Like LCD displays, plasma monitors do
not exhibit the distortion and loss of clarity in the corners inherent to
In July 1964, the idea for plasma display
panels was first created the University of Illinois (USA). During that time,
it was just some light source created in laboratory experiments. By the late
60's, scientists were able to construct geometric shapes with the
advancement of technology. However, further development was limited,
scientists were restricted by the better materials that were available back
then, therefore the screens were small, and image quality was low. Today,
due to the progression in high speed digital processing, materials and
advance manufacturing technology, has made full colour, bright plasma
displays possible. Once what was only thought of as Science Fiction is now
available and ready to use in a host of new and exciting ways.
Figure 14: How gas Plasma work
Plasma displays are unique compared with
other display technologies. Inside this thin panel is a fixed matrix of
imaging pixels, just like an LCD. The zoom in to those pixels resembles
small capacitors with three electrodes (corresponding to the color red, blue
and green). An electrical discharge across these electrodes sandwiched
between two glass panels excite the tiny pockets of noble gas, mainly xenon
and neon, into an ionized form of matter called plasma. This process results
in the production of UV light, which in turn reacts with red, green and blue
phosphor in each pixel to emit visible light. Unlike traditional displays,
where the image is scanned across the screen, images from plasma technology
are created by adjusting the brightness, color and contrast of each pixel.
All these pixels can also light up simultaneously, so there is no scanning
to distort the image as with a CRT. Therefore, having no electron beam,
lighting or light polarization, the image is inherently sharper, brighter
and perfect from edge to edge.
Advantages of plasma
Less sensitive to ambient light
than most LCD, plasma monitors have the brightness and contrast of
Effective visual field angle
Spectators can enjoy sharp, on-screen images from virtually any
viewing point (excess of 160 degrees, both horizontally and vertically)
rather than simply front-on.
Figure 15: Effective visual field angle
Accurate display characteristics
The use of a true flat-panel
screen ensures images displayed are always perfect and distortion-free.
Entire image always in perfect focus, not just in the center, but all the
way to the corners.
Unlike an LCD, plasma does not
require backlighting or polarization. This produces sharper images visible
in any setting, even in direct sunlight.
Consume lesser power than CRTs.
Thin and lightweight
At only 4" - 6" thick and about
60-100 lbs., making them installation-friendly.
Disadvantages of plasma
By nature, plasma displays have
a potential problem with black level. Since the cells always receive
power, there is a small amount of light emanating from every cell, even
those representing black. The inability to adjust a display to absolute
black negatively affects its depth of field.
Plasma is expensive. For that
reason alone, plasma is not for everyone. But prices are coming down, as
they do for most new technologies.
More susceptible to burn-in
It's not a good medium on which
to display a company logo for two or three hours at a time. But with the
appropriate precautions, and in some situations a screen saver, you should
not expect problems.
Plasma is subject to the same type of resolution problems as LCD or DLP
projectors. You'll get the best images when the resolution of your source
matches the "true" resolution of the monitor. But, as with LCD, the
monitors will incorporate compression or expansion circuitry to
automatically resize other resolution sources to match their native
resolution, and most people will be very happy with the result. Still, if
sharpness is critical for your application and you'll be using a variety
of computer sources, you may be better off with a CRT-based unit.
© 2005 Moni-X Ltd. All rights reserved.