Scanning; Additive Mixing - Sony LUMA Product Information Manual

Scanning

An electronic stimulus is applied to the phosphors
by shooting an electron beam at the area that
should light up. The beam, which is driven by
supplying high voltage to the electron gun, is
steered across the phosphor panel from top to
bottom, hitting one point at a time. This is called
'scanning'. The electron beam scans the
phosphor panel at the field or frame rate of the
input video signal.

Additive Mixing

As earlier mentioned, in a color CRT, three beams
are used in combination with three types of
phosphors, which emit either red (R), green (G),
or blue (B) light when stimulated. The scan
pattern of each electron beam is accurately
controlled so the beam hits its corresponding
phosphor - R, G, or B. The phosphors, in turn,
react to the energy provided by these beams and
emit light in proportion to the intensity of the
beams.
Each beam's intensity is controlled according to
the R, G, and B video signals supplied to the
electron gun. Accordingly, the R, G, and B
Blue
Cyan Magenta
White
Green Yellow Red
Figure 2-3. Additive Mixing
The basic mechanisms of display devices
G
B
Beam
Figure 2-2.
phosphors each emit light in proportion to the
input video signal's R, G, and B components. To
the human eye, these R, G, and B lights appear as
one ray of light, as a mixture of the three colors.
This principle is known as 'additive mixing' (see
Figure 2-3). In additive mixing, most hues visible
to the human eye can be composed using the
three primary colors: red, green, and blue. It is
important to note that all other color display
systems, regardless of their operating
mechanisms, also use this principle* to produce
color.
CCD tube CCD t b C C CD tube CCD tube C C CD tube CCD tube
Light
Figure 2-4. * Compared to the color CRT,
color cameras use a reverse
process and convert the captured
images into R, G, and B electric signals.
Electron gun
R
R G
B
R G
B
R G
G B
Phosphor
B B B
B B signal
G G G
Video process
G G signal
R R R
R signal R
Product Information Manual Sony Professional LCD Monitor
B
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