Displays which can see. Adrian Travis Microsoft

Transcription

1 Displays which can see Adrian Travis Microsoft

2 Contents In praise of projection Wedge projection Window-like displays 3D displays

3 Visionaries want offices to have wall-sized displays so that staff work naturally in teams Eindhoven University of Technology University of North Carolina

4 Displays should allow eyecontact interaction

5 Most concepts which are tried out are put into effect using projectors Ars Electronica Futurelab Ars Electronica Futurelab

6 Displays should respond to hand gestures Smart Technologies

7 Surface is the first of a new generation of screens which can watch the user

8 but Surface is much too fat!

9 A ray injected into the edge of a glass slab will be guided by total internal reflection off the glass/air interface glass slab

10 The more ray injection angle differs from the critical angle, the more times the ray must bounce before exit. wedge light guide ray changes direction critical angle reached total internal reflection

11 The more ray injection angle differs from the critical angle, the more times the ray must bounce before exit. distance

12 Add projector to enable three different types of display real 3D virtual

13 Contents In praise of projection Wedge projection Window-like displays 3D displays

14 Point a projector into a wedge, and you get magnification. projected image normal video projector

15 The image must magnify horizontally as well as vertically so the wedge base is elongated..

16 Horizontal magnfication takes place by fan-out in the elongated region.

17 Fold the fan-out region behind the screen

18 Fold the fan-out region behind the screen

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20 Insert a mirror in the rear and tuck the projector into a corner.

21 Turning film Diffusive screen Anti-reflection coating Whole System Will Fit in Simple Thin Casing

22 Images can be projected via a wedge light-guide

23 A wedge panel also works in reverse as a camera object camera

24 At airports, unescorted bags get X-rayed

25 Most bags are left against walls, so use a Wedge panel

26 Wedge X-ray video screen for baggage scanning Scanna scanna-msc.com

27 Contents In praise of projection Wedge projection Window-like displays 3D displays

28 1. Point a projector into a slab with parallel sides 2. Slightly emboss one side with a grating slab video projector

29 3. At each grating reflection, part of the ray diffracts out. The diffracted parts all travel in the same direction

30 when an eye looks at the display, all the rays seem to come from a point far behind the slab video projector

31 4. Inject a ray at a different angle into the slab

32 the diffracted components emerge in a different direction, so seem to come from a different point video projector

33 The slab behaves like a window on a distant image video projector

34 We widen the eye box with a grating in the orthogonal direction video projector

35 These devices are being used in helmet mounted displays q-sight

36 The devices are also being used in aircraft head-up displays q-hud pilot

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38 Contents In praise of projection Wedge projection Window-like displays 3D displays

39 3D needs line rates ~100 times greater than for 2D. y a challenge beyond TFTs? x q f

40 3D needs line rates ~100 times greater than for 2D too fast for TFT s? y x f q

41 Any display can give 3D if slits are put in front

42 Slits convert a good 2D display into a low resolution 3D display slits Wedge projection display

43 Scan slits across a wedge display to get high resolution 3D liquid crystal shutter Wedge projection display

44 Such displays are already available in bulk optics Setred

45 We learn that a space is needed between object & lens, and between lens & image but this need not be so. object plane lens image plane space space

46 The basic function of a lens is to collimate rays emanating from a point, or vice versa

47 All rays leave a correctly designed wedge at the same angle, so a wedge acts as a collimator.

48 Is a wedge a lens? Perhaps, but one of the focal planes is one dimensional

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51 Microdisplays are silicon chips with liquid crystal on top: potentially, they are very cheap.

52 Projectors will become as small and inexpensive as laser diodes allow.

53 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

54 Flat projection is based on a triad of low cost: microdisplays, lasers and sheets of plastic

55 This gives us all three types of image real 3D virtual