How does HUD work?

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sunjerem

New Member
How does a HUD work? Does it work like an overhead projector, and projects an images onto the windscreen?

Also, most of the HUD I've seen in cockpits are positions below a pilot's eye-level. So, how can it be HEAD-UP display?
 
At current, there are two options for reading off the main parameters of a plane: One is the instrument panel inside the cockpit, while the other one is the HUD (Head Up Display).

A head up display is an optical system that superimposes a synthetic display providing navigational or weapon-aiming information on a pilot's or driver's field of view. The system includes a cathode-ray tube, collimating optics and a combiner that projects the image in front of the window. A Head-Up Display projects the display image onto a partially transparent screen called a combiner that reflects the display to the viewer while allowing the viewer to see through to the outside world.

It's called head UP display because when used a pilot (or driver) does not have to look DOWN onto the consoles inside the cockpit to see and check various status and performance indicating devices. One advantage is that the HUD allows the viewer to see the projected display information while still looking at the scene beyond. A GUD is usefull, for example, in allowing a pilot to see both the runway and his instruments simultaneously during landings: you see were you're going while at the same monitoring all necessary information. Another advantage is that the distant display image saves the time needed to refocus the eyes between nearby instruments and the world outside.

You might find this links informative:
http://www.codeonemagazine.com/archives/1986/articles/dec_86/head_up/headup_p.html

http://www.photonics.com/dictionary/images/terms/headupdi.gif

http://www.fou.uib.no/fd/1996/h/404001/IMG00016.GIF

http://www.ef2000.de/images/Ef2000_21.jpg
 
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What about a helmet mounted sight (HMS)?? Is some source projecting onto a transparent panel mounted on the helmet or is the transparent panel carying some sort of a transprenct LCD or maybe a TOLED (Transparent Organic LED)??
 
How to DIY?

Good evening,

I was just wondering if you could give me some advice. These days I am dealing with HUD in a school project. The thing is that the HUD optics seems to be the most difficult part since I study electronics and computers at my uni. I would like to know where to find information how to construct it, which optical elements are need and so on? I would be very grateful for any helping information.

Kind regards
 
xjohny01 said:
Good evening,

I was just wondering if you could give me some advice. These days I am dealing with HUD in a school project. The thing is that the HUD optics seems to be the most difficult part since I study electronics and computers at my uni. I would like to know where to find information how to construct it, which optical elements are need and so on? I would be very grateful for any helping information.

Kind regards
Click to expand...

Challenging project, that. My suggestion would be to look up any relevant patents, just to get a feel for the concepts at work in a HUD. Call around and see if you can get a hold of a researcher or manufacturer. Obviously, they aren't likely to give you proprietary information, but they might be willing to help. And, if you can find one cheap, take it apart and try putting it back together.

-http://www.xflight.de/original/parts/center_console/hud/huddiagram.jpg
-http://www.simlabs.arc.nasa.gov/vms/images/HUDcombiner_t.gif
 
I know that they are starting to have Helmet Mounted Displays, I think it is in service with Typhoon. Most attack helicopters have them too nowadays.

F-35 Helmet Display System To Scare the Bejeezus Out of Enemies

Bit of history: HMDs have been around a bit longer than I thought, interesting that they have taken awhile to become prevalent.

[ame="http://en.wikipedia.org/wiki/Helmet_mounted_display"]Helmet mounted display - Wikipedia, the free encyclopedia@@AMEPARAM@@/wiki/File:Question_book-new.svg" class="image"><img alt="Question book-new.svg" src="http://upload.wikimedia.org/wikipedia/en/thumb/9/99/Question_book-new.svg/50px-Question_book-new.svg.png"@@AMEPARAM@@en/thumb/9/99/Question_book-new.svg/50px-Question_book-new.svg.png[/ame]

Just out of curiosity, has anybody tried to project image/info on the canopy glass instead of old HUD or newer HMDs? Seems to me it would be easier or at least it wouldn't be some bulky/heavy helmet with all the dangers to the pilot when pulling gs or when ejecting.:confused:
 
sunjerem said:
How does a HUD work? Does it work like an overhead projector, and projects an images onto the windscreen?

Also, most of the HUD I've seen in cockpits are positions below a pilot's eye-level. So, how can it be HEAD-UP display?
Click to expand...
It is called a HUD because it is mounted so that you look through it to see your objective/target. If the beam splitter in a military HUD appears below eye level that is an illusion caused by the orientation of the pilots seat. The optimum firing position, for example, typically has the target centered in the HUD, which is also the primary sight.

Basically A HUD uses the same technology as a teleprompter, an angled pane of ‘glass’ (it is actually much more complex than that, involving several layers of materials and/or optical coatings) called a beam splitter that combines 2 beams from perpendicular directions into 1. The projector is mounted below the beam splitter just behind the instrument console.

I do not believe that any design actually projects onto the canopy itself because of the problems with distortion from flexing and heating of the canopy.
 
My2Cents said:
I do not believe that any design actually projects onto the canopy itself because of the problems with distortion from flexing and heating of the canopy.
Click to expand...

It's partly that, but its also something of a semi-unintentional safety feature. Most modern HUD screens are also slipstream-rated, so should the canopy fail, they offer some limited protection for the pilot's face.
 
Kilo 2-3 said:
It's partly that, but its also something of a semi-unintentional safety feature. Most modern HUD screens are also slipstream-rated, so should the canopy fail, they offer some limited protection for the pilot's face.
Click to expand...
It's partly that, but its also something of a semi-unintentional safety feature. The HUD screens is slipstream-rated, so should the canopy fail, it will not come loose and smash the pilot's head.

Same result, different perspective.
 
My2Cents said:
I do not believe that any design actually projects onto the canopy itself because of the problems with distortion from flexing and heating of the canopy.
Click to expand...

I think it has something to do with the complicated lens arrangement associated with trying to project something on a curve surface. The system will be so bulky that you may not have enough space to put a pilot into the cockpit.
 
Car manufacturers have been working with HUD's for decades. Many higher end cars have some incredible HUD features. With advances in glass technology simplified versions will be standard in all cars in the very near future. Just do a Google search and the working principles become obvious very quickly.
 
Holographic HUD

My2Cents said:
It is called a HUD because it is mounted so that you look through it to see your objective/target. If the beam splitter in a military HUD appears below eye level that is an illusion caused by the orientation of the pilots seat. The optimum firing position, for example, typically has the target centered in the HUD, which is also the primary sight.

Basically A HUD uses the same technology as a teleprompter, an angled pane of ‘glass’ (it is actually much more complex than that, involving several layers of materials and/or optical coatings) called a beam splitter that combines 2 beams from perpendicular directions into 1. The projector is mounted below the beam splitter just behind the instrument console.

I do not believe that any design actually projects onto the canopy itself because of the problems with distortion from flexing and heating of the canopy.
Click to expand...

Holographic HUDs are the new technology HUDs being introduced into military aircraft. Can any one eloberate on the technology ? Links to any white papers or detailed technical literature is most welcome
regards
 
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