I think not. I believe they use symbol generators because they are
vector displays and not raster. However, I'm an aero engineer not an
avionics man so i could be wrong.
I did say probably :-). The very first and older HUD's did use
vector graphics, but that technology dates back to the 1960's and
the days of early graphics terminals such as Tektronix. It was the
only way to build hi resolution graphics displays in those days
and it took multiple boards of electronics using hundreds of ic's.
The problem with vector is that the hardware is more complex and
thus less reliable. Raster scan is also cheaper and with the move
to more cots (commercial, rather than mil spec) equipment it
wouldn't surprise me to see raster scan used as the default method
where possible.
The vector approach drives the screen as an x/y plotter, with lines
continuously drawn between two screen coordinates. Well, not quite
true in that those lines will be stored as discreet points along the
path between the two coordinates. Raster scan, on the other hand paints
a dot at the point on the line and builds up the line as a series
of dots. In the early days, vector would have provided the highest
resolution, but raster scan should be capable of similar or equal
performance now.
I think Smiths Industries developed the very first Head Up Display
system. Yet another excellent uk high tech company given away to
the US for a pittance because we couldn't be bothered anymore
...
(Correction: RAE developed the first HUD, with Cintel manufacturing,
but Smiths were heavily involved with the technology)