Newsgroups: sci.electronics
Path: utzoo!utgpu!watserv1!watmath!mwtilden
From: mwtilden@watmath.waterloo.edu (M.W.Tilden, Hardware)
Subject: Re: HeadsUp Display ( WAS Re: Big Screen Projector from tiny LCD TV ? )
Message-ID: <1990Aug29.140124.5490@watmath.waterloo.edu>
Organization: University of Waterloo
References: <32906@cup.portal.com> <2916@anasaz.UUCP> <26da9f56-37c.5sci.electronics-1@vpnet.chi.il.us>
Date: Wed, 29 Aug 90 14:01:24 GMT
Lines: 32

In article <26da9f56-37c.5sci.electronics-1@vpnet.chi.il.us> cgordon@vpnet.chi.il.us (Gordon Hlavenka) writes:
>
>>speaking of removing the backing on LCDs and projecting light through
>>them. Has anybody tried to make a heads up display that way? Something
>>that could be fitted to a helmet or added to glasses. 
>
>This probably wouldn't work well, as you'd have to shift your focus between
>the display and the world.  Try reading something two inches in front of
>you...  True heads-up displays have their focus at infinity, so they are
>easily readable.

To use LCDs as a heads-up, it's better to mount the displays
somewhere about the ears and project them into the eyes by a partially
reflective window.  This avoids the problem of excessive weight and
balance distribution.  A lens assembly still must be added to change
depth perception, but it can be significantly simpler and helmet mounted.  
Having the units around the ears also centralizes all connection 
electronics thus reducing fatigue problems in the circuitry (a 
major problem in any body-mounted electronics).  As an added feature,
you would want the reflection/view planes LCD polarizable so you could
'cut off' the outside world as easy as you adjust the contrast on your
LCD image.  This will allow you to balance the intensity of both
real and virtual images dynamically.

Is all.


-- 
Mark Tilden: _-_-_-__--__--_      /(glitch!)  M.F.C.F Hardware Design Lab.
-_-___       |              \  /\/            U of Waterloo. Ont. Can, N2L-3G1
     |__-_-_-|               \/               (519) - 885 - 1211 ext.2454,
"MY OPINIONS, YOU HEAR!? MINE! MINE! MINE! MINE! MINE! AH HAHAHAHAHAHAHAHAHA!!"
