System and a method of determining the position of a radiation emitting element

• US 7,435,940 B2
• Filed: 03/12/2004
• Issued: 10/14/2008
• Est. Priority Date: 03/12/2003
• Status: Expired due to Fees

• Current Assignee: FlatFrog Laboratories AB
• Original Assignee: FlatFrog Laboratories AB
• Inventors: Eliasson, Jonas Ove Philip, Ostergaard, Jen Wagenblast Stubbe
• Primary Examiner(s): Lee; John R
• Application Number:
  US10/548,664
• Publication Number:
  US 20060255248A1
• Time in Patent Office: 1,677 Days
• Field of Search: 250/221, 250/222.1, 345/173, 345/175, 345/176, 178/18.09
• US Class Current: 250/221
• CPC Class Codes: G06F 3/0386 for light pen
• CPC Class Codes: G06F 3/042 by opto-electronic means

Abstract

A method and a system, such as a touch pad, for determining the position of a radiation emitter, which radiation emitter may be an actively radiation emitting stylus, pen, pointer, or the like or may be a passive, radiation scattering/reflecting/diffusing element, such as a pen, pointer, or a finger of an operator. The radiation is modulated by a bar code element and provided onto an at least one-dimensional detector. From the output of the detector, the position of the radiation emitter is determined. This system may be used as a standard touch pad or for determining the position of emitters external thereto, such as a marker used on a wall or black/white board or may be used with “internal” positions such as a touch pad.

Claims

1. A system for determining a position of an element emitting/reflecting electromagnetic radiation, the emitting/reflecting element contacts a radiation transmissive element and emits/reflects radiation into the radiation transmissive element, the system comprising:

an at least one-dimensional detector having a row of a plurality of individual elements each being adapted to detect radiation and to provide a corresponding signal,

a first elongated radiation transforming element provided on a surface of the radiation transmissive element so that radiation from the emitting/reflecting element travels inside the radiation transmissive element on a radiation path from the emitting/reflecting element to the detector, the first radiation transforming element being arranged in the radiation path and being adapted to modulate electromagnetic radiation from the emitting/reflecting element so as to form a modulated radiation intensity pattern on a row of the detector, and

a determining element adapted to determine, on the basis of the intensity pattern detected by the detector, a position of the emitting/reflecting element.

2. A system according to claim 1, wherein the determining element is adapted to determine a first value related to a distance, on the detector, between at least two predetermined parts of the intensity pattern and adapted to determine the position of the emitting/reflecting element on the basis of the first value.

3. A system according to claim 2, wherein the determining element is adapted to determine one or more second value(s) related to a position, on the detector, of one or more predetermined part(s) of the intensity pattern and adapted to determine the position of the emitting/reflecting element on the basis of the second value(s).

4. A system according to claim 1, wherein the determining element is adapted to determine a position, on the detector, of one or more of a plurality of predetermined parts of the intensity pattern by:

identifying the plurality of predetermined parts of the intensity pattern,

deriving, from the signals from the elements of the detector having detected the individual parts of the intensity pattern, information relating to a shape of the parts of the intensity pattern, and

deriving the position(s) by fitting the shape information to the parts of the intensity pattern.

5. A system according to claim 1, wherein the determining element is adapted to determine a position, on the detector, of one or more of a plurality of predetermined parts of the intensity pattern by:

identifying the plurality of predetermined parts of the intensity pattern,

predetermining a shape of each of the parts of the intensity pattern, and

deriving the position(s) by fitting the predetermined shape to the parts of the intensity pattern.

6. A system according to claim 1, wherein the first radiation transforming element comprises, along its longitudinal direction, an element for reflecting/reducing/absorbing/extinguishing incident electromagnetic information and for transmitting electromagnetic information, having the intensity pattern, toward the detector.

7. A system according to claim 6, wherein the reflecting/reducing/absorbing/extinguishing element is provided in a periodic pattern along the longitudinal direction.

8. A system according to claim 6, wherein the reflecting/reducing/absorbing/extinguishing element is adapted to substantially prevent transmission of electromagnetic radiation therethrough.

9. A system according to claim 6, wherein the first radiation transforming element has its longitudinal axis at an angle to an axis of extension of the detecting elements of the detector.

10. A system according to claim 1, wherein the detector comprises two or more at least one-dimensional detectors, and the system comprises a second radiation transforming element, where electromagnetic radiation transmitted through the first radiation transforming element is incident on one detector and electromagnetic radiation transmitted through the second radiation transforming element is incident on another detector.

11. A system according to claim 10, wherein the first radiation transforming element is adapted to provide radiation that is modulated thereby with a first characteristic, and the second radiation transforming element is adapted to provide radiation that is modulated thereby with a second characteristic, where a first detector is able to detect the first characteristic of radiation and the second characteristic of no radiation, and a second detector is able to detect the second characteristic of radiation and the first characteristic of no radiation.

12. A system according to claim 1, wherein the detector comprises a number of co-extending rows of individual elements, and the first radiation transforming element comprises an element for providing a plurality of radiation lines across the plurality of rows, the radiation lines having a non-perpendicular angle to a direction of the rows.

13. A system according to claim 1, further comprising a second radiation transforming element positioned between the first radiation transforming element and the emitting/reflecting element and being adapted to form a modulated intensity pattern on the first radiation transforming element, the first radiation transforming element further modulates the radiation and provides the modulated radiation on the detector.

14. A system according to claim 13, wherein the system is adapted to receive radiation from the emitting/reflecting element at a first position or area between the first radiation transforming element and the second radiation transforming element and at a second position or area on an opposite side of the second radiation transforming element.

15. A system according to claim 13, wherein the first radiation transforming element and the second radiation transforming element are at least substantially straight elements, and a non-zero angle exists between the elements.

16. A system according to claim 1, wherein the first radiation transforming element is curved.

17. A system according to claim 16, wherein the first radiation transforming element is curved in a direction away from or toward the detector.

18. A system according to claim 13, wherein the first radiation transforming element and the second radiation transforming element are curved, each having a center of curvature, and the centers of curvature are different.

19. A system according to claim 16, further comprising a lens positioned between the first radiation transforming element and the detector.

20. A system according to claim 19, wherein the first radiation transforming element is provided on a surface of the lens.

21. A system according to claim 1, wherein the first radiation transforming element is provided by printing a predetermined pattern on the surface.

22. A system according to claim 1, wherein the emitting/reflecting element is adapted to reflect radiation from a radiation provider toward the first radiation transforming element, the radiation provider being adapted to provide spatially modulated radiation toward the emitting/reflecting element.

23. A method of determining a position of an element emitting/reflecting electromagnetic radiation, the emitting/reflecting element contacts a radiation transmissive element and emits/reflects radiation into the radiation transmissive element, and part of the radiation traveling inside the radiation transmissive element to a first elongated radiation transforming element provided on a side of the radiation transmissive element, the method comprising:

modulating the part of the radiation in the first radiation transforming element, so as to form a modulated radiation intensity pattern,

detecting the modulated radiation intensity pattern with an at least one-dimensional detector having a row with a plurality of individual elements each detecting a separate part of the intensity pattern and providing a corresponding signal, and

determining, on the basis of the intensity pattern detected by the detector, the position of the emitting/reflecting element.

24. A method according to claim 23, wherein the determining step further comprises determining a first value related to a distance, on the detector, between at least two predetermined parts of the intensity pattern and determining the position of the emitting/reflecting element on the basis of the first value.

25. A method according to claim 23, wherein the determining step further comprises determining one or more second value(s) related to a position, on the detector, of one or more predetermined part(s) of the intensity pattern and determining the position of the emitting/reflecting element on the basis of the second value(s).

26. A method according to claim 23, wherein the determining step further comprises determining a position, on the detector, of one or more of a plurality of predetermined parts of the intensity pattern by:

identifying the plurality of predetermined parts of the intensity pattern,

deriving, from the signals from the elements of the detector having detected the individual parts of the intensity pattern, information relating to a shape of the parts of the intensity pattern, and

deriving the position(s) by fitting the shape information to the parts of the intensity pattern.

27. A method according to claim 23, wherein the determining step further comprises determining a position, on the detector, of one or more of a plurality of predetermined parts of the intensity pattern by:

identifying the plurality of predetermined parts of the intensity pattern,

predetermining a shape of the parts of the intensity pattern, and

deriving the position(s) by fitting the predetermined shape to the parts of the intensity pattern.

28. A method according to claim 23, further comprising reflecting/reducing/absorbing/extinguishing electromagnetic radiation incident on the first radiation transforming element and transmitting electromagnetic information, having the intensity pattern, toward the detector.

29. A method according to claim 28, wherein the reflecting/reducing/absorbing/extinguishing step comprises reflecting/reducing/absorbing/extinguishing the radiation using a periodic pattern of one or more radiation reflecting/reducing/absorbing/extinguishing material(s) along a longitudinal direction.

30. A method according to claim 28, wherein the reflecting/reducing/absorbing/extinguishing step comprises substantially preventing transmission of electromagnetic radiation through the first radiation transforming element at one or more positions along a longitudinal direction thereof.

31. A method according to claim 28, wherein the first radiation transforming element has its longitudinal axis at an angle to an axis of extension of the detecting elements of the detector.

32. A method according to claim 23, wherein the detector comprises two or more at least one-dimensional detectors and a second radiation transforming element, the modulation step includes the first transforming element transmitting modulated electromagnetic radiation onto one detector and the second radiation transforming element transmits modulated electromagnetic radiation onto another detector.

33. A method according to claim 32, wherein the first radiation transforming element provides radiation that is modulated thereby with a first characteristic, and the second radiation transforming element provides radiation that is modulated thereby with a second characteristic, where a first detector detects the first characteristic of radiation and the second characteristic of no radiation, and a second detector detects the second characteristic of radiation and the first characteristic of no radiation.

34. A method according to claim 23, wherein the detector comprises a number of co-extending rows of individual elements, and the modulating step comprises an element to provide a plurality of radiation lines across the plurality of rows, the radiation lines having a non-perpendicular angle to a direction of the rows.

35. A method according to claim 23, wherein the modulating step further comprises a second radiation transforming element modulating the radiation from the emitting/reflecting element and providing the modulated radiation on the first radiation transforming element, the first radiation transforming element further modulates the radiation and provides the modulated radiation on the detector.

36. A method according to claim 35, further comprising receiving radiation from the emitting/reflecting element at a first position or area between the first radiation transforming element and the second radiation transforming element and the step of receiving radiation from a second position or area on an opposite side of the second radiation transforming element.

37. A method according to claim 35, wherein the first radiation transforming element and the second radiation transforming element are at least substantially straight elements, and a non-zero angle exists between the elements.

38. A method according to claim 23, wherein the first radiation transforming element is curved.

39. A method according to claim 38, wherein the first radiation transforming element is curved in a direction away from or toward the detector.

40. A method according to claim 35, wherein the first radiation transforming element and the second radiation transforming element are curved each having a center of curvature, where the centers of curvature are different.

41. A method according to claim 38, further comprising a lens means providing the radiation modulated by the first radiation transforming element to the detector.

42. A method according to claim 41, wherein the first radiation transforming element is provided on a surface of the lens means.

43. A method according to claims 23, further comprising the step of providing the first radiation transforming element by printing a predetermined pattern on the surface.

44. A method according to claim 23, wherein the emitting/reflecting element reflects radiation from a radiation provider toward the first radiation transforming element, the radiation provider provides spatially modulated radiation toward the emitting/reflecting element.