Hardware Reference
In-Depth Information
this gas plasma display on its P70 and P75 briefcase portable systems that were released way back in
1988.
Unlike the early IBM monochrome plasma screens, today's plasma displays are capable of displaying
24-bit or 32-bit color. Plasma screens produce an image by using electrically charged gas (plasma) to
illuminate triads of red, green, and blue phosphors, as shown in Figure 12.26 .
Figure 12.26. A cross-section of a typical plasma display.
The display and address electrodes create a grid that enables each subpixel to be individually
addressed. By adjusting the differences in charge between the display and address electrodes for each
triad's subpixels, the signal source controls the picture.
Typical plasma screens range in size from 42 inches to 60 inches or larger. Because they are
primarily designed for use with DVD, TV, or HDTV video sources, they are sized and optimized for
video rather than computer use. Their quick response time makes them good choices for enjoying
sports, streaming HD video, or Blu-ray movies.
LCD and DLP Projectors
Originally, data projectors were intended for use in boardrooms and training facilities. However,
with the rise of home theater systems, the increasing popularity of working from home, and major
price reductions and improvements in projector technology, portable projectors are an increasingly
popular alternative to large-screen TVs and plasma displays.
Two technologies are used in the construction of data projectors:
• Liquid crystal display (LCD)
• DLP
Instead of using triads of subpixels as in a flat-panel or portable LCD, an LCD projector works by
separating white light into red, green, and blue wavelengths and directing each wavelength through a
corresponding LCD panel. Each LCD panel's pixels are opened or closed according to the signals
received from the signal source (computer, DVD, or video player) and are combined into a single
RGB image that is projected onto the screen. A relatively hot projection lamp must be used to project
LCD images, so LCD projectors require some cool-down time before they can be stored.
 
 
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