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

• US 7,442,914 B2
• Filed: 09/09/2004
• Issued: 10/28/2008
• Est. Priority Date: 09/12/2003
• Status: Expired due to Fees

• Current Assignee: FlatFrog Laboratories AB
• Original Assignee: FlatFrog Laboratories AB
• Inventors: Eliasson, Jonas Ove Philip, Østergaard, Jens Wagenblast Stubbe
• Primary Examiner(s): Lee; John R
• Application Number:
  US10/571,561
• Publication Number:
  US 20070201042A1
• Time in Patent Office: 1,510 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 3/0428 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 method and a system 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 from the emitter is reflected from that position toward the detector by a reflecting element providing multiple intensity spots on the detector providing sufficient information for determining the position. From the output of the detector, the position of the radiation emitter is determined.

Claims

1. A system for determining a position of an radiation emitting element, the system comprising:

a radiation transmissive member adapted to receive, at a surface thereof, radiation emitted by the emitting element and adapted to guide radiation therein by total internal reflection,

an at least one-dimensional detector including a plurality of individual elements each being adapted to detect radiation and to provide a corresponding signal, the detector being adapted to receive radiation from a first edge part of the radiation transmissive member, and

a reflecting element at a second edge part of the radiation transmissive member, the reflecting element being adapted to reflect light incident thereon from inside the radiation transmissive member back into the radiation transmissive member and adapted to reflect radiation emitted from the emitting element toward the detecting elements of the detector, the detector includes one or more apertures, pinholes, or lenses provided between the detecting elements and the emitting element, and between the detecting elements and the reflecting element, and

a device for determining the position of the emitting element, on the basis of the signal of the detector relating to radiation which is received directly from the emitting element and to radiation which is emitted by the emitting element and reflected toward the detector by the reflecting element.

2. A system according to claim 1, wherein the detector comprises a single row of detecting elements.

3. A system according to claim 1, wherein the reflecting element is straight.

4. A system according to claim 1, wherein the reflecting element is curved.

5. A system according to claim 1, wherein the reflecting element comprises at least two straight parts at an angle to each other, each straight part of the reflecting element is adapted to reflect radiation emitted by the emitting element toward the detector.

6. A system according to claim 1, wherein the detector, the reflecting element, and the emitting element are adapted to be positioned in a predetermined plane.

7. A system according to claim 6, wherein the detector and the reflecting element are attached to a predetermined surface.

8. A system according to claim 6, wherein the emitting element is adapted to emit radiation from a radius thereof.

9. A system according to claim 7, wherein the emitting element comprises a stationary radiation emitter and a movable reflecting part, the stationary radiation emitter being positioned so as to emit radiation toward the movable reflecting element at at least part of a field of view of the detector in a manner so that radiation is reflected, by the movable reflecting part, toward both the detector and the reflective element.

10. A system according to claim 1, wherein the emitting element is an element adapted to emit radiation from an end part thereof and into the radiation transmissive member.

11. A system according to claim 1, wherein the emitting element comprises a radiation emitter and a scattering element, the radiation emitter being positioned so as to emit radiation into the radiation transmissive member and the scattering element is adapted to scatter radiation, such as at a surface of the radiation transmissive member, toward the detector and the reflective element.

12. A system according to claim 1, wherein the determining device is adapted to determine a plurality of radiation intensity peaks over the detector and, from the positions of the peaks, determine the position of the emitting element.

23. A system according to claim 1, wherein the reflecting element and the detector are provided in a self-contained unit.

13. A method of determining a position of an electromagnetic radiation emitting element, the method comprising:

emitting the radiation into a radiation transmissive member adapted to guide radiation therein by total internal reflection,

detecting, at a first edge part of the radiation transmissive member and using an at least one-dimensional detector having a plurality of individual elements, each element detecting radiation and providing a corresponding signal, radiation emitted by the emitting element,

reflecting, at a second edge of the radiation transmissive member and using a reflecting element reflecting light incident thereon from inside the radiation transmissive member back into the radiation transmissive member, radiation emitted from the emitting element toward the detector, the detecting step includes transmitting the radiation from the reflecting element and the emitting element through one or more apertures, pinholes, or lenses before detecting the radiation, and

determining the position of the emitting element, on the basis of the signal of the detector relating to radiation which is received directly from the emitting element and to radiation which is emitted by the emitting element and reflected toward the detector by the reflecting element.

14. A method according to claim 13, wherein the detector comprises a single row of detecting elements.

15. A method according to claim 13, wherein the reflecting element comprises at least two straight parts at an angle to each other, each straight part of the reflecting element reflects radiation emitted by the emitting element toward the detector.

16. A method according to claim 13, further comprising the step of positioning the detector, the aperture/pinhole/lens, the reflecting element and the emitting element in a predetermined plane.

17. A method according to claim 16, further comprising the step of attaching or fixing the detector, the aperture/pinhole/lens and the reflecting element to a predetermined surface.

18. A method according to claim 16, wherein the emitting element emits radiation from a radius thereof.

19. A method according to claim 16, wherein the emitting element comprises a stationary radiation emitter and a moving reflecting element, the radiation emitter emitting radiation towards the reflecting element so that radiation is reflected towards both the detector and the reflective element.

20. A method according to claim 13, wherein the emitting element emits radiation from an end part thereof and into the radiation transmissive member.

21. A method according to claim 13, wherein the emitting element comprises a radiation emitter and a scattering element, the radiation emitter emits radiation into the radiation transmissive member and the scattering element scatters at a surface of the radiation transmissive member, radiation toward the detector and the reflective element.

22. A method according to claim 13, wherein the determining step comprises determining a plurality of radiation intensity peaks over the detector and, from the positions of the peaks, determining the position of the emitting element.