Touch Sensing

• US 20100302196A1
• Filed: 06/01/2010
• Published: 12/02/2010
• Est. Priority Date: 06/01/2009
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Perceptive Pixel Incorporated (Microsoft Corporation)
• Inventors: Han, Jefferson Y., Kollin, Joel S.
• Granted Patent: US 9,323,396 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G02B 6/0016 Grooves, prisms, gratings, scattering particles or rough surfaces
• CPC Class Codes: G02B 6/34 utilising prism or grating G02B6/293 takes precedence
• CPC Class Codes: G02B 6/4204 the coupling comprising intermediate optical elements, e.g. lenses, holograms encapsulated active devices H01S5/02208, H01L33/52
• 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 touch-screen device includes an imaging waveguide, in which the imaging waveguide has a radiation receiving surface and an imaging surface different than the radiation receiving surface. The imaging waveguide is configured to receive, at the radiation receiving surface, radiation emitted by a contact receiving structure, and transmit the received radiation from a position on the radiation receiving surface to a position and/or angle of incidence on the imaging surface as a function of the position on the radiation receiving surface at which the transmitted radiation was received. An imaging sensor coupled to the imaging surface of the imaging optical waveguide is configured to detect radiation incident upon the imaging surface of the imaging optical waveguide. A processing device coupled to the imaging sensor is configured to determine contact points on the exposed contact surface of a contact receiving structure based on radiation detected by the imaging sensor.

Claims

1. A touch-screen device comprising:

a contact receiving structure having an exposed contact surface for receiving contact by one or more input mechanisms, the contact receiving structure being configured to emit radiation as a consequence of contact with the exposed contact surface by an input mechanism at a contact point, the emitted radiation being emitted by a region of the contact receiving structure that corresponds to the contact point;

an imaging waveguide having a radiation receiving surface and an imaging surface that is different than the radiation receiving surface, the imaging waveguide being configured to;

receive, at the radiation receiving surface, radiation emitted by the contact receiving structure, and

transmit received radiation from a position on the radiation receiving surface to a position and with an angle of incidence on the imaging surface that are each a function of the position on the radiation receiving surface at which the transmitted radiation was received;

an imaging sensor that is optically coupled to the imaging surface of the imaging optical waveguide and that is configured to detect radiation incident upon the imaging surface of the imaging optical waveguide; and

a processing device configured to determine contact points on the exposed contact surface of the contact receiving structure based on the radiation detected by the imaging sensor.

2. The device of claim 1 wherein the imaging waveguide is configured to transmit the received radiation by total internal reflection.

3. The device of claim 2 wherein the imaging waveguide comprises a first side and a second side, the second side having a length that extends in a direction substantially orthogonal to a direction extended by a length of the first side, the length of the second side being shorter than the length of the first side, wherein the first side comprises the radiation receiving surface and the second side comprises the imaging surface.

4. The device of claim 1 wherein the imaging waveguide is formed to have a tapered shape.

5. The device of claim 4 wherein the imaging waveguide is configured to transmit the received radiation by total internal reflection.

6. The device of claim 1 wherein the imaging waveguide comprises a diffractive optical element.

7. The device of claim 6 wherein the diffractive optical element comprises a thin hologram structure.

8. The device of claim 7 wherein the thin hologram structure comprises a blazed grating.

9. The device of claim 6 wherein the diffractive optical element comprises a thick hologram structure.

10. The device of claim 6 wherein the diffractive optical element is located adjacent to the radiation receiving surface.

11. The device of claim 6 wherein the diffractive optical element is located adjacent to a surface of the imaging waveguide opposite to the radiation receiving surface.

12. The device of claim 1 wherein the imaging waveguide comprises a refractive optical element.

13. The device of claim 12 wherein the refractive optical element comprises Fresnel prisms.

14. The device of claim 12 wherein the refractive optical element comprises Fresnel lenses.

15. The device of claim 12 wherein the refractive optical element is located adjacent to the radiation receiving surface.

16. The device of claim 12 wherein the refractive optical element is located adjacent to a surface of the imaging waveguide opposite to the radiation receiving surface.

17. The device of claim 1 wherein the imaging waveguide comprises a reflective layer opposite the radiation receiving surface.

18. The device of claim 1 wherein the radiation receiving surface comprises an anti-reflection layer.

19. The device of claim 18 wherein the anti-reflection layer comprises a plurality of alternating high refractive index and low refractive index layers.

20. The device of claim 19 wherein the anti-reflection layer comprises an array of protrusions, each protrusion having a height and width smaller than a wavelength associated with the radiation emitted by the contact receiving surface.

21. The device of claim 1 further comprising a lens between the imaging sensor and the imaging surface of the imaging waveguide.

22. The device of claim 1 further comprising a display device between the contact receiving structure and the imaging waveguide.

23. The device of claim 22 wherein the display device comprises a liquid crystal device.

24. The device of claim 22 wherein the display device comprises a light emitting diode device.

25. The device of claim 24 wherein the light emitting diode device comprises an organic light emitting diode device.

26. The device of claim 1 wherein the contact receiving structure comprises a waveguide layer and a pliable frustrating layer disposed relative to the waveguide layer so as to enable the pliable frustrating layer to contact the waveguide layer when the pliable frustrating layer is physically deformed by the input mechanism at the contact point, the pliable frustrating layer being configured to:

cause frustration, at an interface between the pliable frustrating layer and the waveguide, of radiation propagating within the waveguide by total internal reflection when the pliable frustrating layer is physically deformed to contact the waveguide layer such that some of the radiation undergoing total internal reflection within the waveguide is emitted from the contact receiving structure at the interface between the pliable frustrating layer and the waveguide.

27. The device of claim 1 wherein the contact receiving structure comprises a pliable waveguide and a frustrating layer disposed relative to the pliable waveguide so as to enable the pliable waveguide to contact the frustrating layer when the pliable waveguide is physically deformed by the input mechanism at the contact point, the frustrating layer being configured to:

cause frustration, at an interface between the frustrating layer and the pliable waveguide, of radiation propagating within the pliable waveguide by total internal reflection when the pliable waveguide is physically deformed to contact the frustrating layer such that some of the radiation undergoing total internal reflection within the pliable waveguide is emitted from the contact receiving structure at the interface between the frustrating layer and the pliable waveguide.

28. A touch-screen device comprising:

a contact receiving structure having an exposed contact surface for receiving contact by one or more input mechanisms, the contact receiving structure being configured to emit radiation as a consequence of contact with the exposed contact surface by an input mechanism at a contact point, the emitted radiation being emitted by a region of the contact receiving structure that corresponds to the contact point; and

a radiation steering structure configured to;

receive the emitted radiation from the contact receiving structure at a first position, and

re-direct the received radiation at an angle that is a function of the first position.

29. The device of claim 28 further comprising:

an imaging sensor configured to detect the re-directed radiation; and

a processing device configured to determine contact points on the exposed contact surface of the contact receiving structure based on the re-directed radiation detected by the imaging sensor.

30. The device of claim 29, wherein the radiation steering structure is further configured to re-direct the received radiation to a position on a detection surface of the imaging sensor, the position on the detection surface being a function of the first position.

31. The device of claim 28, wherein the radiation steering structure comprises a diffractive optical element.

32. The device of claim 31, wherein the diffractive optical element comprises a thin hologram structure.

33. The device of claim 31, wherein the diffractive optical element comprises a thick hologram structure.

34. The device of claim 28, wherein the radiation steering structure comprises a refractive optical element.

35. The device of claim 28, wherein the radiation steering structure is further configured to transmit the received radiation through the radiation steering structure.

36. The device of claim 28, wherein the radiation steering structure is further configured to reflect the received radiation from the radiation steering structure.

37. The device of claim 28, wherein the radiation steering structure comprises a reflective structure.

38. The device of claim 35, wherein the reflective structure comprises a single mirror.

39. The device of claim 35, wherein the reflective structure comprises a plurality of mirrors.

40. The device of claim 28, further comprising a display device between the contact receiving structure and the radiation steering structure.

41. The device of claim 40, wherein the display device comprises a liquid crystal device.

42. The device of claim 40, wherein the display device comprises a light emitting diode device.

43. The device of claim 42, wherein the light emitting diode device comprises an organic light emitting diode device.