Multi-user touch screen

• US 20080088593A1
• Filed: 10/12/2006
• Published: 04/17/2008
• Est. Priority Date: 10/12/2006
• Status: Active Grant

• Current Assignee: Disney Enterprises Incorporated (The Walt Disney Company)
• Original Assignee: Disney Enterprises Incorporated (The Walt Disney Company)
• Inventors: SMOOT, LANNY STARKES
• Granted Patent: US 8,022,941 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 2203/04109 FTIR in optical digitiser, i.e. touch detection by frustrating the total internal reflection within an optical waveguide due to changes of optical properties or deformation at the touch location
• CPC Class Codes: G06F 3/0425 using a single imaging device like a video camera for tracking the absolute position of a single or a plurality of objects with respect to an imaged reference surface, e.g. video camera imaging a display or a projection screen, a table or a wall surface, on which a computer generated image is displayed or projected tracking a projected light spot to determine a position on a display surface G06F3/0386

Abstract

A multi-user touch-responsive viewing screen is described which uses frustrated total internal reflection in a slab of transparent material to illuminate the contact point between the slab and a finger or other object substantially matching the slab'"'"'s index of refraction. Light, coupled upon touch, can be detected with a video camera, and used to determine both the position and pressure of the touch. Multiple touches can be accommodated and each touch accurately located. Projected images can be applied to the slab and a diffuser to construct an interactive touch screen.

Claims

1. A method of detecting touch on a touch-screen surface, comprising:

providing a transparent slab, the transparent slab comprising a top surface and a bottom surface, and at least one side edge;

injecting light into the transparent slab by placing at least one light source on the at least one side edge of the transparent slab, the at least one light source being placed so as to cause light injected in the transparent slab to be totally internally reflected in the transparent slab so that the top surface and the bottom surface of the transparent slab emit a minimum amount of light;

receiving touch on the transparent slab with a body part of the user, wherein the touch of the user on the transparent slab disrupts the total internal reflection of a portion of the light thereby causing the portion of the light to be refracted into the body part of the user; and

capturing with a camera the portion of the light refracted into the body part of the user due to the touch of the body part on the transparent slab.

2. The method of claim 1, wherein the top surface and the bottom surface are smooth.

3. The method of claim 1, wherein the transparent slab is made of glass.

4. The method of claim 1, wherein the transparent slab is made of plastic.

5. The method of claim 1, wherein the transparent slab is made of plastic and glass.

6. The method of claim 5, further comprising projecting an image on a projection screen that is separate from the transparent slab.

7. The method of claim 1, further comprising projecting an image on a computer monitor that is separate from the transparent slab.

8. The method of claim 1, wherein the user touches the top surface of the transparent slab with a finger, the camera capturing the light being refracted into the finger.

9. The method of claim 1, wherein the user touches the bottom surface of the transparent slab with a finger, the camera capturing the light being refracted into the finger.

10. The method of claim 1, wherein the camera further captures a subportion of the light that was refracted into the body part and reflected off the body part onto the transparent slab.

11. The method of claim 1, wherein the camera captures the portion of the light refracted into the body part of the user and transmits a signal to a computer system as user input.

12. The method of claim 11, wherein the computer system, as a response to the user input, transmits to a projector an image to be projected on a projection screen.

13. The method of claim 11, wherein the computer system, as a response to the user input, transmits to a projector an image to be projected on a computer monitor.

14. The method of claim 11, wherein the computer system, as a response to the user input, transmits to a projector an image to be projected on a diffusing surface.

15. The method of claim 11, wherein the computer system is a video processing system that interprets the captured portion of the light as a touch signal.

16. The method of claim 11, wherein the signal is representative of the X and Y position of the light refracted into the body part of the user with respect to the transparent slab.

17. The method of claim 1, wherein the camera captures as an electrical signal the portion of the light refracted into the body part of the user, the electrical signal being transmitted to a computer system as user input.

18. The method of claim 1, wherein the transparent slab is flat.

19. The method of claim 1, wherein the transparent slab is curved.

20. The method of claim 1, wherein the camera is a shutter camera, the method further comprising:

turning the at least one light source on;

capturing a first video frame with the shutter camera so as to capture ambient light and the portion of the light refracted into the body part of the user;

turning the at least one light source off;

capturing a second video frame with the shutter camera so as to capture the ambient light; and

subtracting the second video frame from the first video frame to create a third video frame that excludes ambient light, wherein the third video frame includes a signal representative of the touch of the user on the transparent slab.

21. The method of claim 20, wherein the time between turning the at least one light source on and turning the at least one light source off is one millisecond.

22. The method of claim 1, further providing a plurality of transparent slabs that are positioned side by side.

23. The method of claim 22, further comprising a plurality of cameras that capture each of the plurality of slabs.

24. The method of claim 1, wherein the camera is configured to detect a greater presence of light when the body part of the user exerts high pressure on the transparent slab.

25. The method of claim 1, further comprising providing a flexible transparent sheet applied on the top surface of the transparent slab, the flexible transparent sheet being separated from the transparent slab by separators that create a thin layer of air.

26. The method of claim 25, wherein the flexible transparent sheet can be pressed against the transparent slab thereby permitting a portion of the light to refract into the body part of the user.

27. The method of claim 26, further comprising releasing pressure off the flexible transparent sheet, wherein the flexible transparent sheet is immediately released away from the transparent slab so as to restore the thin layer of air.

28. The method of claim 26, further comprising releasing pressure off the flexible transparent sheet, wherein the flexible diffusing sheet is released away from the transparent slab after a predetermined amount of time so as to restore the thin layer of air.

29. The method of claim 26, further comprising releasing pressure off the flexible transparent sheet, wherein the flexible transparent sheet remains pressed against the transparent slab.

30. A method of detecting touch on a touch-screen surface with an improved signal-to-noise ratio, comprising:

providing a transparent slab, the transparent slab comprising a top surface and a bottom surface, and at least one side edge;

injecting light into the transparent slab by placing at least one light source on the at least one side edge of the transparent slab, the at least one light source being placed so as to cause light injected in the transparent slab to be totally internally reflected in the transparent slab;

receiving touch on the transparent slab with a body part of the user, wherein the touch of the user on the transparent slab disrupts the total internal reflection of a portion of the light thereby causing the portion of the light to be refracted into the body part of the user; and

turning the at least one light source on;

capturing a first video frame with a first shutter camera so as to capture ambient light and the portion of the light refracted into the body part of the user;

turning the at least one light source off;

capturing a second video frame with a second shutter camera so as to capture the ambient light; and

subtracting the second video frame from the first video frame to create a third video frame that excludes ambient light, wherein the third video frame includes a signal representative of the touch of the user on the transparent slab.

31. The method of claim 30, wherein the transparent slab is flat.

32. The method of claim 30, wherein the transparent slab is curved.

33. The method of claim 30, wherein the camera captures the portion of the light refracted into the body part of the user and transmits a signal to a computer system as user input.

34. The method of claim 33, wherein the computer system, as a response to the user input, transmits to a projector an image to be projected on a projection screen.

35. The method of claim 30, further comprising providing a flexible transparent sheet applied on the top surface of the transparent slab, the flexible transparent sheet being separated from the transparent slab by separators that create a thin layer of air.

36. A system to detect touch on a touch-screen surface, comprising:

a transparent slab, the transparent slab comprising a top and a bottom surface, and at least one side edge;

at least one light source placed to inject light in the at least one side edge of the transparent slab, wherein the light injected in the transparent slab is totally internally reflected in the transparent slab so that the top surface and the bottom surface of the transparent slab emit a minimum amount of light; and

a camera configured to capture at least one spot of light in the transparent slab, wherein the at least spot of light is created by a user touching the transparent slab with a body part, wherein the touch of the user on the transparent slab disrupts the total internal reflection of a portion of the light thereby causing the portion of the light to be refracted into the body part of the user.

37. The system of claim 36, wherein the transparent slab is comprised of a layer of plastic material and a layer of glass.

38. The system of claim 36, wherein the transparent slab further comprises a transparent sheet applied on the top surface of the transparent slab in order to protect the transparent slab.

39. The system of claim 38, wherein the transparent slab is comprised of a layer of plastic material and a layer of glass.

40. The system of claim 36, further comprising a pliable index-matching layer, with spacers, then through pressure, and then it lights up, in order to be detected instantly.

41. The system of claim 36, further comprising a video processing system that includes a video peak detector to detect the X and Y position and brightness of blobs of light on the transparent slab.

42. The system of claim 36, wherein the camera captures as a video frame the portion of the light refracted into the body part of the user, the video frame being transmitted to a computer system as user input.

43. The system of claim 42, further comprising a projector, wherein the computer system, as a response to the user input, transmits to the projector an image to be projected on a diffusing surface, the diffusing surface being separate from the transparent slab.

44. The system of claim 36, wherein the camera is a shutter camera configured to capture a first video frame comprising a spot of light in the transparent slab when the at least one light source is turned on, wherein the camera is further configured to capture a second video frame with the shutter camera so as to capture the ambient light when the at least one light source is turned off, the system further comprising:

a subtractor that subtracts the second video frame from the first video frame to create a third video frame that excludes ambient light, wherein the third video frame includes a signal representative of the touch of the user on the transparent slab.

45. The system of claim 44, further comprising a first frame store wherein the first frame is stored before subtraction occurs, and a second frame store wherein the second frame is stored before subtraction occurs.

46. The system of claim 44, further comprising a synchronizing unit that is configured to simultaneously send a signal to shutter camera and to the at least one light source such that the shutter camera can capture the first frame when the at least one light source is on, and the second frame when the at least one light source is off.

47. A system to detect touch on a touch-screen surface, comprising:

a transparent slab, the transparent slab comprising a top and a bottom surface, and at least one side edge;

at least one light source placed to inject light in the at least one side edge of the transparent slab, wherein the light injected in the transparent slab is totally internally reflected in the transparent slab so;

a first shutter camera configured to capture a first video frame comprising a spot of light in the transparent slab when the at least one light source is turned on, wherein the spot of light is created by a user touching the transparent slab with a body part, wherein the touch of the user on the transparent slab disrupts the total internal reflection of a portion of the light thereby causing the portion of the light to be refracted into the body part of the user;

a second shutter camera configured to capture a second video frame comprising ambient light near the transparent slab when the at least one light source is turned off; and

a subtractor that subtracts the second video frame from the first video frame to create a third video frame that excludes ambient light, wherein the third video frame includes a signal representative of the touch of the user on the transparent slab.

48. The system of claim 47, further comprising a first frame store wherein the first frame is stored before subtraction occurs, and a second frame store wherein the second frame is stored before subtraction occurs.

49. The system of claim 47, further comprising a synchronizing unit that is configured to simultaneously send a signal to shutter camera and to the at least one light source such that the shutter camera can capture the first frame when the at least one light source is on, and the second frame when the at least one light source is off.

50. A method of detecting touch on a touch-screen surface, comprising:

providing a transparent slab, the transparent slab comprising a top surface and a bottom surface, and at least one side edge, wherein the top surface and the bottom surface are smooth;

injecting light into the transparent slab by placing at least one light source on the at least one side edge of the transparent slab, the at least one light source being placed so as to cause light injected in the transparent slab to be totally internally reflected in the transparent slab;

receiving touch on the transparent slab with a body part of the user, wherein the touch of the user on the transparent slab disrupts the total internal reflection of a portion of the light thereby causing the portion of the light to be refracted into the body part of the user; and

capturing with a camera the portion of the light refracted into the body part of the user due to the touch of the body part on the transparent slab.

51. The method of claim 50, wherein the transparent slab is flat.

52. The method of claim 50, wherein the transparent slab is curved.

53. The method of claim 50, wherein the camera captures the portion of the light refracted into the body part of the user and transmits a signal to a computer system as user input.

54. The method of claim 53, wherein the computer system, as a response to the user input, transmits to a projector an image to be projected on a projection screen.

55. The method of claim 50, further comprising providing a flexible transparent sheet applied on the top surface of the transparent slab, the flexible transparent sheet being separated from the transparent slab by separators that create a thin layer of air.

56. A method of detecting touch on a touch-screen surface, comprising:

providing a transparent slab, the transparent slab comprising a top surface and a bottom surface, and at least one side edge;

applying a flexible diffusing sheet on the top surface of the transparent slab, the flexible diffusing sheet being separated from the transparent slab by separators that create a thin layer of air between the flexible diffusing sheet and the transparent slab;

injecting light into the transparent slab by placing at least one light source on the at least one side edge of the transparent slab, the at least one light source being placed so as to cause light injected in the transparent slab to be totally internally reflected in the transparent slab so that the top surface and the bottom surface of the transparent slab emit a minimum amount of light;

receiving a pressing touch on the flexible diffusing sheet, wherein the pressing touch causes a portion the flexible diffusing sheet to make contact with a portion of the top surface of the transparent slab, wherein the contact between the flexible diffusing sheet and the portion of the top surface of the transparent slab disrupts the total internal reflection of a portion of the light thereby causing the portion of the light to be refracted into the flexible diffusing sheet; and

capturing with a camera the portion of the light refracted into the flexible diffusing sheet due to the pressing touch on the flexible diffusing sheet.

57. The method of claim 56, further comprising releasing the pressing touch off the flexible diffusing sheet, wherein the flexible diffusing sheet is immediately released away from the transparent slab so as to restore the thin layer of air.

58. The method of claim 56, further comprising releasing the pressing touch off the flexible diffusing sheet, wherein the flexible diffusing sheet is released away from the transparent slab after a predetermined amount of time so as to restore the thin layer of air.

59. The method of claim 58, wherein upon the flexible diffusing sheet being released away from the transparent slab, the portion of the light ceases to be refracted into the flexible diffusing sheet.

60. The method of claim 56, further comprising releasing the pressing touch off the flexible diffusing sheet, wherein the flexible diffusing sheet remains pressed against the transparent slab.

61. The method of claim 60, wherein upon the flexible diffusing sheet being pulled away from the transparent slab, the portion of the light ceases to be refracted into the flexible diffusing sheet.

62. A method of detecting touch on a touch-screen surface, comprising:

providing a transparent slab, the transparent slab comprising a top slab surface and a bottom slab surface, and at least one side edge;

applying a transparent yielding sheet on the top slab surface of the transparent slab, wherein the transparent yielding sheet has an index of refraction substantially similar to the index of refraction of the transparent slab, the transparent yielding sheet comprising a top sheet surface and a bottom sheet surface;

injecting light into the transparent slab by placing at least one light source on the at least one side edge of the transparent slab, the at least one light source being placed so as to cause light injected into the transparent slab to be totally internally reflected in the transparent slab and transparent yielding sheet, so that the top sheet surface and the bottom slab surface emit a minimum amount of light;

receiving a pressing touch on the top sheet surface with a body part, wherein the pressing touch causes a portion the transparent yielding sheet to deform to the shape of the pressing touch, wherein the pressing touch disrupts the total internal reflection of a portion of the light thereby causing the portion of the light to be refracted into the body part; and

capturing with a camera the portion of the light refracted into the body part due to the pressing touch on the flexible sheet.

63. The method of claim 62, wherein the pressing touch increases a contact surface area of the body part of the user and the transparent yielding sheet and further improves an index match between the top slab surface and the body part of the user.

64. The method of claim 62, wherein the transparent yielding sheet is made from rubber material.

65. The method of claim 62, wherein the transparent yielding sheet is made from silicone material.

66. The method of claim 62, wherein the transparent slab is flat.

67. The method of claim 62, wherein the transparent slab is curved.

68. The method of claim 62, wherein the camera captures the portion of the light refracted into the body part of the user and transmits a signal to a computer system as user input.

69. The method of claim 68, wherein the computer system, as a response to the user input, transmits to a projector an image to be projected on a projection screen.