Illuminated bezel and touch system incorporating the same

• US 6,972,401 B2
• Filed: 01/30/2003
• Issued: 12/06/2005
• Est. Priority Date: 01/30/2003
• Status: Expired due to Term

• Current Assignee: Smart Technologies ULC (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Smart Technologies Incorporated (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Morrison, Gerald D., Akitt, Trevor M., Bullock, Neil Gordon
• Primary Examiner(s): Le, Que T.
• Application Number:
  US10/354,168
• Publication Number:
  US 20040149892A1
• Time in Patent Office: 1,041 Days
• Field of Search: 250/221, 250/239, 250/216, 250/226, 250/559.29, 345/166, 345/173, 345/175
• US Class Current: 250/221
• CPC Class Codes: G06F 3/03547 Touch pads, in which fingers can move on a surface
• CPC Class Codes: G06F 3/0428 by sensing at the edges of the touch surface the interruption of optical paths, e.g. an illumination plane, parallel to the touch surface which may be virtual sensing beam interruptions in a planar beam grid of an optical touch-screen G06F3/0421

Abstract

A passive touch system includes a touch surface and at least one source of backlight illumination projecting backlighting across the touch surface. At least two image sensors are associated with the touch surface and acquire images of the touch surface from different locations. A digital signal processor is associated with each image sensor. The digital signal processors select pixel subsets of images acquired by the image sensors and process pixel data acquired by the selected pixel subsets to generate pointer characteristic data when a pointer exists in the acquired images. A master digital signal processor in communication with the digital signal processors triangulates the pointer characteristic data to determine the location of the pointer relative to the touch surface.

Claims

1. In a touch system including a touch surface and at least one optical sensor looking along the touch surface to acquire images of a pointer in proximity thereto, an illumination source to provide backlighting to said at least one optical sensor comprising:

at least one light source; and

a diffuser disposed between said at least one light source and said at least one optical sensor, said diffuser diffusing light projected by said at least one light source prior to said light being directed across the touch surface to said at least one optical sensor.

2. An illumination source according to claim 1 wherein said at least one light source is at least one discrete light source.

3. An illumination source according to claim 2 wherein said at least one light source includes a plurality of spaced discrete light sources.

4. An illumination source according to claim 3 wherein said discrete light sources are arranged in at least one row.

5. An illumination source according to claim 4 wherein said discrete light sources are arranged in a two-dimensional array.

6. An illumination source according to claim 5 wherein said two-dimensional array includes a plurality of stacked rows of discrete light sources.

7. An illumination source according to claim 3 wherein said discrete light sources are generally equally spaced.

8. An illumination source according to claim 3 wherein the spacing between said discrete light sources is non-linear.

9. An illumination source according to claim 3 wherein said discrete light sources are spaced such that the light projected onto the diffuser by adjacent discrete light sources overlaps.

10. An illumination source according to claim 9 wherein said spacing is such that the light projected onto the diffuser by adjacent discrete light sources significantly overlaps.

11. An illumination source according to claim 3 wherein said discrete light sources are spaced such that the light projected onto the diffuser by adjacent discrete light sources abuts.

12. An illumination source according to claim 3 wherein said discrete light sources are spaced such that the light projected onto the diffuser by adjacent discrete light sources is spaced apart.

13. An illumination source according to claim 3 wherein said diffuser diffuses the light projected by said discrete light sources so that the light directed to said at least one optical sensor is generally continuous across said illumination source.

14. An illumination source according to claim 3 wherein said diffuser is generally transparent in a specified frequency range.

15. An illumination source according to claim 14 wherein said diffuser is generally opaque in a different specified frequency range.

16. An illumination source according to claim 15 wherein said discrete light sources are infrared light emitting diodes (IR LEDs) and wherein said diffuser is generally transparent in the infrared range.

17. An illumination source according to claim 16 wherein said diffuser is generally opaque in the visible light spectrum.

18. An illumination source according to claim 3 wherein said diffuser further polarizes the light prior to being directed to said at least one optical sensor.

19. An illumination source according to claim 1 wherein said at least one light source is a continuous light source.

20. An illumination source according to claim 19 wherein said continuous light source projects light in the infrared spectrum.

21. An illumination source according to claim 19 wherein said continuous light source projects light in the visible spectrum and wherein said illumination source further includes a color filter through which said light passes.

22. An illumination source according to claim 21 wherein said color filter is adjacent to said diffuser.

23. An illumination source according to claim 21 wherein said diffuser acts as said color filter.

24. A touch system comprising:

at least one optical sensor associated with a touch surface and having a field of view encompassing and looking across at least a portion of said touch surface;

at least one source of backlight illumination directing light into the field of view of said at least one optical sensor, said at least one illumination source including at least one light source and a diffusion medium to expand light projected by said at least one light source prior to said light being directed into said field of view; and

a pass filter associated with said at least one optical sensor to pass the light directed by said source of backlight illumination to said at least one optical sensor.

25. A touch system according to claim 24 wherein said source of backlight illumination extends at least partially along one side of said touch surface opposite said at least one optical sensor.

26. A touch system according to claim 25 wherein said source of backlight illumination extends generally the length of said one side.

27. A touch system according to claim 26 wherein said source of backlight illumination includes a plurality of spaced discrete light sources.

28. A touch system according to claim 27 wherein said discrete light sources are spaced such that the light projected onto the diffusion medium by adjacent discrete light sources overlaps.

29. A touch system according to claim 28 wherein said diffusion medium expands the light projected by said discrete light sources so that the light directed to said at least one optical sensor is generally continuous across said at least one source of backlight illumination.

30. A touch system according to claim 29 wherein said diffusion medium is generally transparent in a specified frequency range.

31. A touch system according to claim 30 wherein said diffusion medium is generally opaque in a different specified frequency range.

32. A touch system according to claim 31 wherein said discrete light sources are infrared light emitting diodes (IR LEDs) and wherein said diffusion medium is generally transparent in the infrared range, said pass filter being an infrared pass filter.

33. A touch system according to claim 32 wherein said diffusion medium is generally opaque in the visible light spectrum.

34. A touch system according to claim 27 wherein said diffusion medium further polarizes the light being directed to said at least one optical sensor.

35. A touch system according to claim 24 wherein said at least one light source is a continuous light source.

36. A touch system according to claim 35 wherein said continuous light source projects light in the visible spectrum and wherein said source of backlight illumination further includes a color filter through which said backlight illumination passes.

37. An illumination source according to claim 36 wherein said color filter is adjacent to said diffusion medium.

38. An illumination source according to claim 37 wherein said diffusion medium acts as said color filter.

39. A touch system according to claim 35 wherein said continuous light source projects light in the infrared spectrum.

40. A touch system according to claim 26 including a plurality of optical sensors adjacent corners of said touch surface and a plurality of sources of backlight illumination extending along sides of said touch surface.

41. A passive touch system comprising:

a touch surface;

at least one source of backlight illumination projecting backlighting across said touch surface;

at least two image sensors associated with said touch surface, said at least two image sensors acquiring images of said touch surface from different locations and having overlapping fields of view;

a pass filter associated with each of said image sensors generally to blind said image sensors except to said projected backlighting;

a digital signal processor associated with each image sensor, the digital signal processors associated with said at least two image sensors selecting pixel subsets of images acquired by said at least two image sensors and processing pixel data acquired by the selected pixel subsets to generate pointer characteristic data when a pointer exists in said acquired images; and

a master digital signal processor in communication with said digital signal processors, said master digital signal processor receiving pointer characteristic data from said digital signal processors and triangulating the pointer characteristic data to determine the location of said pointer relative to said touch surface.

42. A passive touch system according to claim 41 including a plurality of sources of backlight illumination.

43. A passive touch system according to claim 42 wherein each source of backlight illumination extends along a different side of said touch surface.

44. A passive touch system according to claim 43 wherein said sources of backlight illumination project light directly into the fields of view of said at least two image sensors.

45. A passive touch system according to claim 44 wherein said sources of backlight illumination appear as continuous light sources to said at least two image sensors.

46. A passive touch system according to claim 45 including an image sensor at each corner of said touch surface and a source of backlight illumination along each side of said touch surface.

47. A touch system comprising:

at least two CMOS image sensors associated with a touch surface, said at least two CMOS image sensors acquiring images of said touch surface from different locations and having overlapping fields of view;

at least one source of backlight illumination projecting backlighting across said touch surface through a diffuser;

a pass filter associated with each of said image sensors generally to blind said image sensors except to said projected backlighting; and

at least one processor receiving and processing image data acquired by said at least two CMOS image sensors to detect the existence of a pointer in said images and to determine the location of said pointer relative to said touch surface.

48. A touch system according to claim 47 including a plurality of sources of backlight illumination.

49. A touch system according to claim 48 wherein each source of backlight illumination extends along a different side of said touch surface.

50. A touch system according to claim 49 wherein said sources of backlight illumination project light directly into the fields of view of said at least two image sensors.

51. A touch system according to claim 50 wherein said sources of backlight illumination appear as continuous light sources to said at least two CMOS image sensors.

52. A touch system according to claim 51 include a CMOS image sensor at each corner of said touch surface and a source of backlight illumination along each side of said touch surface.

53. A touch system comprising:

at least two optical recording devices associated with a touch surface, said at least two optical recording devices acquiring images of said touch surface from different locations and having overlapping fields of view;

at least one source of backlight illumination projecting backlighting across said touch surface;

a pass filter associated with said optical recording devices generally to blind said optical recording devices except to said projected backlighting; and

a processor receiving and processing image data acquired by said at least two optical recording devices to detect the existence of a pointer in said images and to determine the location of said pointer relative to said touch surface, wherein said processor includes first and second processing stages, said first processing stage including a plurality of digital signal processors each associated with a respective one of said optical recording devices, said digital signal processors processing pixel data from pixel subsets of said optical recording devices and generating pointer parameter data, said second processing stage processing said pointer parameter data from said first processing stage to determine the location of the pointer.

54. A touch system according to claim 53 wherein said second processing stage includes a master digital signal processor receiving said pointer parameter data from said digital signal processors, said master digital signal processor triangulating said pointer parameter data.

55. A touch system according to claim 53, wherein a third processing stage includes a personal computer receiving the location of said pointer relative to said touch surface from said master digital signal processor.

56. A touch system according to claim 53 including a plurality of sources of backlight illumination.

57. A touch system according to claim 56 wherein each source of backlight illumination extends along a different side of said touch surface.

58. A touch system according to claim 57 wherein said sources of backlight illumination project light directly into the fields of view of said at least two optical recording devices.

59. A touch system according to claim 58 wherein said sources of backlight illumination appear as continuous light sources to said at least two optical recording devices.

60. A touch system according to claim 59 including an optical recording device at each corner of said touch surface and a source of backlight illumination along each side of said touch surface.

61. An imaging assembly comprising:

a substantially rectangular bezel to surround a display surface;

at least one optical sensor mounted on said bezel, said at least one optical sensor being oriented to have a field of view looking along said display surface;

at least one source of backlight illumination within said bezel projecting backlight illumination through a diffuser into said field of view; and

a pass filter associated with said at least one optical sensor to pass the light directed by said source of backlight illumination to said at least one optical sensor.

62. An imaging assembly according to claim 61 include an optical sensor at each corner of said bezel and a source of backlight illumination within each side of said bezel.

63. An imaging assembly according to claim 62 wherein said sources of backlight illumination appear as continuous light sources to said optical sensors.

64. An imaging assembly according to claim 63 wherein said bezel includes side frame assemblies joined by corner pieces, said side frame assemblies including housing elements engaging said display surface and accommodating said sources of backlight illumination and said corner pieces accommodating said optical sensors.

65. An imaging assembly according to claim 63 wherein each optical sensor is a CMOS digital camera.

66. An imaging assembly according to claim 65, wherein each CMOS digital camera has a selectable pixel array.

67. An imaging assembly according to claim 64 wherein each source of backlight illumination includes a plurality of spaced discrete light sources.

68. An imaging assembly according to claim 63 wherein each source of backlight illumination includes a continuous light source.

69. A method of detecting the position of a pointer relative to a touch surface comprising the steps of:

acquiring multiple images of a pointer relative to said touch surface;

selecting pixel subsets of said acquired images;

processing pixel data acquired by the pixel subsets to detect the existence of said pointer therein and to determine the location of the pointer relative to the touch surface using triangulation; and

during said acquiring providing backlight illumination across said touch surface and acquiring said images based on said backlight illumination.