apr01 09 presentation
Post on 14-Jun-2015
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Displays which can see
Adrian Travis
Microsoft
Contents
• In praise of projection
• Wedge projection
• Window-like displays
• 3D displays
Eindhoven University of Technologyhttp://www.ipsi.fraunhofer.de/ambiente/english/projekte/projekte/roomware.html
Visionaries want offices to have wall-sized displays so that staff work naturally in teams
University of North Carolina
http://www.cs.unc.edu/~andrei/artagrafica/technical/of.jpg
Displays should allow eye-contact interaction
Ars Electronica Futurelab
http://90.146.8.18/en/archives/center_projekt_ausgabe.asp?iProjectID=11026
Most concepts which are tried out are put into effect using projectors
Ars Electronica Futurelab
Displays should respond to hand gestures
http://www2.smarttech.com/NR/rdonlyres/3919073A-A684-4C30-8D57-
37BD175816E5/0/INT960AtlantisSecondarySchoolSouthAfricaCaseStudyREV0lowres.pdf
Smart Technologies
Surface is the first of a new generation of screens which can watch the user
but Surface is much too fat!
glass slab
A ray injected into the edge of a glass slab will be guided by total internal reflection off the glass/air interface
total internal
reflection
ray changes
direction
critical angle
reached
wedgelight guide
The more ray injection angle differs from the critical angle, the more times the ray must bounce before exit.
distance
The more ray injection angle differs from the critical angle, the more times the ray must bounce before exit.
Add projector to enable three different types of display
real
virtual
3D
Contents
• In praise of projection
• Wedge projection
• Window-like displays
• 3D displays
Point a projector into a wedge, and you get magnification.
projectedimage
normal video projector
The image must magnify horizontally as well as vertically so
the wedge base is elongated..
Horizontal magnfication takes place by fan-out in the
elongated region.
Fold the fan-out region behind the screen
Fold the fan-out region behind the screen
Insert a mirror in the rear and tuck the projector into a corner.
Diffusive
screen
Anti-reflection coating
Turning film
Whole System Will Fit in Simple Thin
Casing
Images can be projected via a
wedge light-guide
A wedge panel also works in reverse as a camera
object
camera
At airports, unescorted bags get X-rayed
Most bags are left against walls, so use a Wedge panel
Wedge X-ray video screen for baggage scanning
scanna-msc.com
http://www.scanna-msc.com/scanwedge.htm
Scanna
Contents
• In praise of projection
• Wedge projection
• Window-like displays
• 3D displays
2. Slightly emboss one side with a grating
video projector
1. Point a projector into a slab with parallel sides
slab
3. At each grating reflection, part of the ray diffracts out. The diffracted parts all travel in the same direction
video projector
…when an eye looks at the display, all the rays seem to come from a point far behind the slab
4. Inject a ray at a different angle into the slab
…the diffracted components emerge in a different direction, so seem to come from a different point
video projector
video projector
The slab behaves like a window on a distant image
video projector
We widen the eye box with a grating in the orthogonal direction
These devices are being used in helmet mounted displays
http://www.baesystems.com/ProductsServices/bae_prod_eis_qsight.html
q-sight
The devices are also being used in aircraft head-up displays
http://www.eis.na.baesystems.com/media_resources/images/q-hud_%20headroom.jpg
http://www.eis.na.baesystems.com/media_resources/images/q-hud_combiner_glass.jpg
q-hud
pilot
Contents
• In praise of projection
• Wedge projection
• Window-like displays
• 3D displays
3D needs line rates ~100 times greater than for 2D.
x
yy
q
f
…a challenge beyond TFTs?
3D needs line rates ~100 times greater than for 2D
x
y
f
q
…too fast for TFT’s ?
Any display can give 3D if slits are put in front
Wedge projection
display
Slits convert a good 2D display into a low resolution 3D display
slits
Wedge projection
display
liquid crystal
shutter
Scan slits across a wedge display to get high resolution 3D
Such displays are already available in bulk optics
http://www.setred.com/displays
Setred
We learn that a space is needed between object & lens, and between lens & image but this need not be so.
object
plane
image
planelens
space space
The basic function of a lens is to collimate rays emanating from a point, or vice versa
All rays leave a correctly designed wedge at the same angle, so a wedge acts as a collimator.
Is a wedge a lens? Perhaps, but one of the focal planes is one dimensional
Microdisplays are silicon chips with liquid crystal on top: potentially, they are very cheap.
Projectors will become as small and inexpensive as laser diodes allow.
We can make the projector flat. In effect data gets from chip to screen by optics instead of wires.
• 1 mm thick?
• Primary colours
• Flexible?
• Chip-on-plastic
• Data rates for 3D
Flat projection is based on a triad of low cost: microdisplays, lasers and sheets of plastic
This gives us all three types of image
real
virtual
3D
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