From: sbray@M3.ips.ca (Jeffrey K. Bray)
Subject: TECH: Auto-focus VR helmet Construction
Date: Sat, 26 Aug 1995 12:11:51 GMT
Message-ID: <41oejo$hip@donatello.leonardo.net>


I'm a student of Computer Science, and together with an Engineering
student, we wanted to build our own VR helmet (for various reasons) to
solve most of the annoyances of the ones out there.  What we need is
input/feedback from people (VR-users, physicsts, medical health
professionals (optomotrists, etc) ) .. Here were our observations (please,
comment and extrapolate): 

We examined and tested an VICTORMAXX helmet:

- Weight on bridge of nose uncomfortable	

	We would like to redistribute the weight on the top of the head or
on the back, seeing that there is nothing there except straps and knobs. 

- Much adjusting, focussing, etc in order to get a half-decent picture
(annoying and discouraging, because we never got it right)

	I thought of a time I went to my optomotrist.  She had me put my
forehead on a plate and look into a little device (which wrapped around my
head a bit) .. After hitting a switch, a green cross appeared (VERY out of
focus), then it seemed to move (forward??) in small steps while making a
clicking noise and when it came into focus for ME, it stopped.  Then, it
would back up (back out of focus), and take another run at it.  After 3
runs at it, it apparently had an accurate idea of where my eyes focus.  .. 

	Can I use this technology to auto-focus a VR helmet? Perhaps when
a user puts it on, there is a quick calibration procedure they go through
which would include this.. 

- Lenses were way too far away from the eyes.  Gave the exact feeling of
operating a camcorder while looking at the viewfinder from a foot away. 
After everything was a bit okay, I felt like I was looking through
binoculars... my field of vision was terrible.  Resolution wasn't that
great at all either. 

	My engineer friend came up with a real crack-pot idea, and I don't
think it's a good idea, but I'm going to bounce it off everybody anyway
(I'm no expert in medical optics :))

	My friend said that if we could have LASERS point directly at the
eyes, and use peizo-crystal controlled mirrors for "scanning" the image.
(there would be a Red laser, a Green laser, and a Blue laser, of course).. 
The effect would be an image RIGHT on the eye (not on a screen in front of
the eye) and the lasers and crystals would be able to move precisely
enough to get a small, high resolution image.

	He seems to think that if you keep the lasers at a low enough power
level, it would not harm the retina of the eye.. 
	My position on this is that the lasers (if not harmful) would need
some sort of translucent surface to project on, such as a frosted contact
lens. 

	If I am right, and this IS a crack-pot idea, :) , what are the
options of getting the image as close to eye as possible, so as to provide
a TRUE immersion?? 

- After pushing on the helmet to get the lenses closer to the eyes, we
realized it was now impossible to focus the lenses (the focus control is
right on the lenses (which were now sitting on my eye).. so I had to take
the helmet off, adjust the focus, put it back on ... 

	I think this would be easily solved by extending the focus rings
back through the front of the helmet, so you can instinctivly reach in
front of you, grab the knobs, and adjust.. 

SUGGESTIONS ? :)

--
Jeffrey K. Bray
Department of Computer Science
Dalhousie University
bray@ips.ca