I don’t know enough about
DLP units, but I think they are a liquid crystal variant with a color wheel timed to give you the illusion of the colors.
DLP systems do (often) have a color wheel, but the
DLP device itself is nothing like an
LCD panel in its operation. They consist of an
array of itsy bitsy mirrors that can be tilted under electronic control. Tilted one way, they reflect the light from
the light source through the color wheel and into the
lens system; tilted the other way, it's instead directed away to a light
trap of some sort. Different brightness levels for the pixels are achieved using
PWM or variable duty cycles, I presume. (There are, of course, a couple other ways of getting color: having more than one
DLP array, one for each primary, or having an
LED or other light source that can change colors rapidly enough.)
Anyhow, it is essentially immune to
burn-in; there's no basic mechanism whereby a ghost
image would appear. It would be possible for a given
pixel's mirror mechanism to break and make a stuck
pixel, but that would be pretty much independent of what
image is being displayed since it's operating continually regardless--excepting, possibly, pure black and/or pure white pixels.