HEAD UP DISPLAY
History:
- HUDs evolved from the reflector sight
- The first sight to add information to rudimentary reflector sight was the gyro gunsight that projected an air speed and turn rate modified reticle to aid in leading the guns to hit a moving target (deflection aircraft gun aiming.
The origin of the name stems from the pilots being able to view
information with heads "up" and looking forward,instead of angled
down looking at lower instrument.
Heads-up displays, or HUDs, are the future. Though they
are already commonplace in gaming interfaces, as well as some advanced vehicles
(and even some widely available cars), HUDs will only gain popularity, making
their way into glasses, visors, mirrors, and all sorts of interfaces.
A typical HUD contains three primary components
Ø combiner
The combiner is the part of the unit located directly in
front of the pilot, providing the surface onto which the information is
projected for view. Combiners can be concave or flat, and have a special
coating that reflects the monochromatic light projected onto it from the
projector unit while allowing all other wavelengths of light to pass through. On some
aircraft the combiners are easily removable (or can be rotated out of the way)
by aircrew.
Ø projector
unit:
The
projection unit projects the image onto the combiner for the pilot to view. In
early HUDs, this was done using refraction,
although modern HUDs use reflection.
Projection units use Cathode Ray Tubes, light emitting diodes,
or liquid
crystal displays to project the image. Projection units can be either
below (as with most fighter aircraft) or above (as with transport/commercial
aircraft) combiners
Ø
video generation computer:
The
computer is usually located with the other avionics equipment and provides the
interface between the HUD (i.e. the projection unit) and the systems/data to be
displayed. On aircraft, these computers are typically dual independent
redundant systems.
Application:-
- Aircraft
- Automobile
- In NASA
- Pilot goggles .. or in many field…
Aircraft:
All the necessary flight information is displayed on the
HUD so that you can fly the aircraft while looking outside.
- As a part of the Airbus continuous effort to enhancethe flight safety, HUD is considered as a tool to...•Increase the pilot situation awareness.•Increase approach stability•Increase landing accuracyProvide a flexible platform for growth using new technologies .
- The airspeed is displayed (in knots) with a speed tape and the current value.
- The magnetic heading with a tape and the current value.
- The flight path vector .
- The radio-altitude (in feet), which is the height of the aircraft above the ground level.
Automobile:
The displays are becoming increasingly
available in production cars, and usually offer speedometer, tachometer,
and navigation system displays

