This is the measure used to
determine how crisp the display of a CRT (Cathode Ray Tube)
monitor is. It is measured in millimeters and the smaller the
number, the finer the picture. Most CRT monitors will have a
dot pitch between .25 and .28. However, some large presentation
monitors have dot pitches from .30 to .50 (which would make
for really fuzzy images on a standard 17" desktop monitor).
The difference between a "dot" (as in dot pitch) and
a
pixel is that a pixel is mapped
onto the dots on the screen. When the monitor is set to lower
resolutions, one pixel encompasses multiple dots. So pixels
are typically larger than the "dots" on the actual
screen.
In a CRT display with
a shadow mask, the dot pitch is measured as the distance between
the holes of the shadow mask, again in millimeters. "So
what's a shadow mask?" you ask. It's basically a metal
screen full of holes where three electron beams (red, green,
and blue) pass through. These beams focus to a single point
on the tube's phosphor surface. Thousands of these points make
up the images on your screen. Neat, huh? In a CRT display that
uses an aperture grill (like a Sony Trinitron monitor), the
dot pitch is measured by the distance between adjacent slots
where electron beams of the same color pass through.
