Dual mode touch systems

• US 8,274,496 B2
• Filed: 10/31/2008
• Issued: 09/25/2012
• Est. Priority Date: 04/29/2004
• Status: Expired due to Fees

• Current Assignee: PixArt Imaging Incorporated
• Original Assignee: Smart Technologies ULC (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Ung, Chi Man Charles, Booth, David Kenneth, Sirotich, Roberto A. L.
• Primary Examiner(s): Tran, My-Chau T
• Application Number:
  US12/262,221
• Publication Number:
  US 20090146973A1
• Time in Patent Office: 1,425 Days
• Field of Search: 345/156, 345/173, 345/175, 345/176, 345/179, 345/180, 178/18.01, 178/18.03, 178/18.09, 178/18.11, 178/19.01, 178/19.05
• US Class Current: 345/176
• CPC Class Codes: G06F 3/03545 Pens or stylus
• CPC Class Codes: G06F 3/042 by opto-electronic means
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen

Abstract

An apparatus for detecting a pointer includes a waveguide and a touch surface over the waveguide on which pointer contacts are to be made. At least one reflecting device extends along a first side of the waveguide and touch surface. The reflecting device defines an optical path between the interior of the waveguide and the region of interest above the touch surface. At least one imaging device looks across the touch surface and into the waveguide. The imaging device captures images of the region of interest and within the waveguide including reflections from the reflecting device.

Claims

1. An apparatus for detecting a pointer comprising:

a waveguide;

a touch surface over said waveguide on which pointer contacts are to be made;

at least one reflecting device extending along a first side of said waveguide and touch surface, said reflecting device defining an optical path between the interior of said waveguide and a region of interest above said touch surface;

at least one imaging device looking across said touch surface and into said waveguide, said at least one imaging device capturing images of said region of interest and within said waveguide including reflections from said reflecting device; and

a lens constituted by a smoothly curved cutout provided in said waveguide, said at least one imaging device being accommodated by said cutout, said cutout including a highly polished surface through which said at least one imaging device looks into said waveguide.

2. An apparatus according to claim 1 further comprising first reflective surfaces extending along a second side of said waveguide and touch surface, said second side joining said first side at a first corner, said first reflective surfaces facing the interior of said waveguide and said region of interest, said at least one imaging device capturing images of said region of interest and within said waveguide including reflections from said reflecting device and said first reflective surfaces.

3. An apparatus according to claim 2 further comprising a processing device to process images captured by said at least one imaging device to determine the location of said pointer relative to said touch surface.

4. An apparatus according to claim 3 wherein said at least one imaging device looks into said waveguide and into said region of interest from a second corner diagonally opposite said first corner.

5. An apparatus according to claim 3 wherein said pointer is illuminated when in contact with said touch surface, said at least one imaging device capturing images including the illuminated pointer and reflections thereof in said reflecting device and first reflective surfaces.

6. An apparatus according to claim 5 wherein said pointer illuminates when contacting said touch surface.

7. An apparatus according to claim 6 wherein said pointer emits infrared radiation when contacting said touch surface, said pointer and reflections thereof appearing in captured images as bright regions against a dark background.

8. An apparatus according to claim 3 further comprising at least one light source operable to provide backlight illumination for said at least one imaging device, said pointer and reflections thereof appearing in captured images as dark regions against a bright background when a pointer is brought into contact with said touch surface and occludes said illumination.

9. An apparatus according to claim 8 wherein said illumination is infrared illumination.

10. An apparatus according to claim 9 wherein said at least one imaging device looks into said waveguide and into said region of interest from a second corner diagonally opposite said first corner, said apparatus comprising a pair of light sources each providing backlight illumination for said at least one imaging device, one of said light sources extending along a side of said waveguide from said second corner to said reflecting device and another of said light sources extending from said second corner to said first reflective surfaces.

11. An apparatus according to claim 10 wherein said illumination sources provide backlight illumination for said at least one imaging device when a passive pointer is used to contact said touch surface and are conditioned to an off state when an active pointer is used to contact said touch surface.

12. An apparatus according to claim 11 wherein said active pointer generates output that is used to condition said illumination sources to said off state.

13. An apparatus according to claim 12 wherein said active pointer illuminates when in contact with said touch surface, said active pointer generating said output when illuminated.

14. An apparatus according to claim 13 wherein said active pointer illuminates in the infrared range.

30. An apparatus according to claim 3 wherein said first reflective surfaces are constituted by a continuous mirror abutting the second side of said waveguide and extending above said touch surface.

31. An apparatus according to claim 30 further comprising second reflective surfaces extending along a third side of said waveguide and touch surface, said third side joining said first side at a second corner, said second reflective surfaces facing the interior of said waveguide and said region of interest, said at least one imaging device capturing images of said region of interest and within said waveguide including reflections from said reflecting device and said first and second reflective surfaces.

32. An apparatus according to claim 31 wherein said second reflective surfaces are constituted by a continuous mirror abutting the third side of said waveguide and extending above said touch surface.

33. An apparatus according to claim 3 wherein said first reflective surfaces are constituted by a polished second side surface of said waveguide and a mirror extending along said second side above said touch surface.

34. An apparatus according to claim 33 further comprising second reflective surfaces extending along a third side of said waveguide and touch surface, said third side joining said first side at a second corner, said second reflective surfaces facing the interior of said waveguide and said region of interest, said at least one imaging device capturing images of said region of interest and within said waveguide including reflections from said reflecting device and said first and second reflective surfaces.

35. An apparatus according to claim 34 wherein said second reflective surfaces are constituted by a polished third side of said waveguide and a mirror extending along said third side above said touch surface.

15. An apparatus for detecting a pointer comprising:

a waveguide,

a touch surface over said waveguide on which pointer contacts are to be made;

at least one reflecting device extending along a first side of said waveguide and touch surface, said reflecting device defining an optical path between the interior of said waveguide and a region of interest above said touch surface;

at least one imaging device looking across said touch surface and into said waveguide;

first reflective surfaces extending along a second side of said waveguide and touch surface, said second side joining said first side at a first corner, said first reflective surfaces facing the interior of said waveguide and said region of interest, said at lease one imaging device capturing images of said region of interest and within said waveguide including reflections from said reflecting device and said first reflective surfaces; and

a processing device to process images captured by said at least one imaging device to determine the location of said pointer relative to said touch surface, wherein said reflecting device is a turning prism assembly.

16. An apparatus for detecting a pointer comprising:

a waveguide;

a touch surface over said waveguide on which pointer contacts are to be made;

at least one reflecting device extending along a first side of said waveguide and touch surface, said reflecting device defining an optical path between the interior of said waveguide and a region of interest above said touch surface;

at least one imaging device looking across said touch surface and into said waveguide;

first reflective surfaces extending along a second side of said waveguide and touch surface, said second side joining said first side at a first corner, said first reflective surfaces facing the interior of said waveguide and said region of interest;

second reflective surfaces extending along a third side of said waveguide and touch surface, said third side joining said first side at a second corner, said second reflective surfaces facing the interior of said waveguide and said region of interest, said at least one imaging device capturing images of said region of interest and within said waveguide including reflections from said reflecting device and said first and second reflective surfaces; and

a processing device to process images captured by said at least one imaging device to determine the location of said pointer relative to said touch surface, wherein said at least one imaging device looks into said waveguide and region of interest from a fourth side of said waveguide, said fourth side being opposite said first side and wherein said at least one imaging device looks into said waveguide via a lens, said lens being constituted by a smoothly curved cutout provided in said waveguide, said at least one imaging device being accommodated by said cutout, said cutout including a highly polished surface through which said at least one imaging device looks.

17. An apparatus according to claim 16 wherein said at least one imaging device is generally centrally disposed along said fourth side.

18. An apparatus according to claim 17 further comprising at least one light source operable to provide backlight illumination for said at least one imaging device, said pointer and reflections thereof appearing in captured images as dark regions against a bright background when a pointer is brought into contact with said touch surface and occludes said illumination.

19. An apparatus according to claim 18 wherein said illumination is infrared illumination.

20. An apparatus according to claim 18 wherein said apparatus comprises a pair of light sources, each providing backlight illumination for said at least one imaging device, said light sources extending along said fourth side on opposite sides of said at least one imaging device.

21. An apparatus according to claim 20 wherein said illumination sources provide backlight illumination for said at least one imaging device when a passive pointer is used to contact said touch surface and are conditioned to an off state when an active pointer is used to contact said touch surface.

22. An apparatus according to claim 21 wherein said active pointer generates output that is used to condition said illumination sources to said off state.

23. An apparatus according to claim 22 wherein said active pointer illuminates when in contact with said touch surface, said active pointer generating said output when illuminated.

24. An apparatus according to claim 23 wherein said active pointer illuminates in the infrared range.

36. An apparatus according to claim 20 wherein said light sources provide backlight illumination for said at least one imaging device having an intensity insufficient to saturate said at least one imaging device and wherein in an active mode, an active pointer emitting light having an intensity greater than that provided by said light sources is used to contact said touch surface.

25. An apparatus for detecting a pointer comprising:

a waveguide;

a touch surface over said waveguide on which pointer contacts are to be made;

at least one reflecting device extending along a first side of said waveguide and touch surface, said reflecting device defining an optical path between the interior of said waveguide and a region of interest above said touch surface;

at least one imaging device looking across said touch surface and into said waveguide, said at least one imaging device capturing images of said region of interest and within said waveguide including reflections from said reflecting device;

a lens constituted by a smoothly curved cutout provided in said waveguide, said at least one imaging device being accommodated by said cutout, said cutout including a highly polished surface through which said at least one imaging device looks into said waveguide; and

a pair of illumination sources, one of said illumination sources extending along a second side, said second side joining said first side at a first corner diagonally opposite said at least one imaging device and another of said illumination sources extending along a third side of said waveguide and touch surface, said third side extending from said at least one imaging device to said one illumination source, said illumination sources providing backlight illumination for said at least one imaging device.

26. An apparatus according to claim 25 wherein said illumination sources provide backlight illumination for said at least one imaging device when a passive pointer is used to contact said touch surface and are conditioned to an off state when an active pointer is used to contact said touch surface.

27. An apparatus according to claim 26 wherein said active pointer generates output that is used to condition said illumination sources to said off state.

28. An apparatus according to claim 27 wherein said active pointer illuminates when in contact with said touch surface, said active pointer generating said output when illuminated.

29. An apparatus according to claim 28 wherein said active pointer illuminates in the infrared range.

37. An apparatus for detecting a pointer comprising:

a waveguide;

a touch surface over said waveguide on which pointer contacts are to be made;

at least one reflecting device extending along a first side of said waveguide and touch surface, said reflecting device defining an optical path between the interior of said waveguide and a region of interest above said touch surface;

at least one imaging device looking into said waveguide, said at least one imaging device capturing images within said waveguide including reflections from said reflecting device; and

a lens constituted by a smoothly curved cutout provided in said waveguide, said at least one imaging device being accommodated by said cutout, said cutout including a highly polished surface through which said at least one imaging device looks into said waveguide.

38. An apparatus according to claim 37 further comprising a second reflecting device surfaces extending along a second side of said waveguide, said at least one imaging device capturing images within said waveguide including reflections from said reflecting devices.

39. An apparatus according to claim 38 further comprising a processing device to process images captured by said at least one imaging device to determine the location of said pointer relative to said touch surface.

40. An apparatus according to claim 39 wherein said at least one imaging device looks into said waveguide from a corner thereof.

41. An apparatus according to claim 40 further comprising at least one light source operable to provide backlight illumination for said at least one imaging device, reflections of said pointer appearing in captured images as dark regions against a bright background when a pointer is brought into contact with said touch surface and occludes said illumination.

42. An apparatus according to claim 41 wherein said illumination is infrared illumination.