Optic having a cladding

• US 8,358,901 B2
• Filed: 05/28/2009
• Issued: 01/22/2013
• Est. Priority Date: 05/28/2009
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Large, Timothy Andrew
• Primary Examiner(s): Le, Uyen-Chau N
• Assistant Examiner(s): CHU, CHRIS H
• Application Number:
  US12/474,014
• Publication Number:
  US 20100302209A1
• Time in Patent Office: 1,335 Days
• Field of Search: None
• US Class Current: 385/146
• CPC Class Codes: G02B 6/10 of the optical waveguide type G02B6/02, G02B6/24 take precedence; devices or arrangements for the control of light by electric, magnetic, electro-magnetic or acoustic means G02F1/00; transferring the modulation of modulated light G02F2/00; optical logic elements G02F3/00; optical analogue/digital converters G02F7/00
• 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

Various embodiments of wedge-shaped light guide optics are disclosed. One embodiment comprises a wedge-shaped light guide having opposing first and second faces and includes a material having a first refractive index. The first face of the wedge-shaped light guide supports a cladding layer having a second refractive index less than the first refractive index. The optic further comprises a turning film bonded to the cladding layer via an interface layer. The interface layer has a third refractive index matched to the first refractive index.

Claims

1. An optic comprising:

a wedge-shaped light guide having opposing first and second faces and comprising a material having a first refractive index, the first face supporting a cladding layer having a second refractive index less than the first refractive index; and

a turning film bonded to the cladding layer via an interface layer, the interface layer presenting a third refractive index extending from the cladding layer to the turning film, the third refractive index matched to the first refractive index, wherein the optic is configured to attenuate a reflection of light having a median wavelength λ and

wherein the thickness d of the cladding layer is given by

2. The optic of claim 1, wherein the cladding layer is a first cladding layer, and wherein the second face supports a second cladding layer bonded to the second face and having a fourth refractive index less than the second refractive index.

3. The optic of claim 1 configured to transmit light laterally between the opposing first and second faces at least partly via total internal reflection from a boundary of the cladding layer.

4. The optic of claim 1, wherein the interface layer comprises an adhesive.

5. The optic of claim 4, wherein the adhesive comprises a polyacrylic adhesive.

6. The optic of claim 4, wherein the adhesive comprises an ultravioletcurable adhesive.

7. The optic of claim 1, wherein the cladding layer comprises a fluoropolymer.

8. The optic of claim 1, wherein the light whose reflection is attenuated is incident on a boundary of the cladding layer at an angle less than a Snell'"'"'s Law critical angle for the boundary, the angle measured normal to the boundary.

9. The optic of claim 1, wherein the turning film comprises a plurality of facets oblique to the first face of the wedge-shaped light guide and supporting a reflective coating.

10. The optic of claim 1, wherein the cladding layer comprises a moth-eye structure.

11. The optic of claim 1, wherein the cladding layer comprises a silicone polymer.

16. The system of claim 7, wherein the wedge-shaped light guide includes:

adjacent to the first and second faces, a thicker side supporting a reflective coating; and

adjacent to the first and second faces, a thinner side opposite the thicker side, wherein the image-creating subsystem is configured to project the image into the thinner side.

17. The system of claim 7, wherein the light source is configured to direct visible light through an image-forming light valve and into the optic.

18. The system of claim 7, wherein the light source is configured to direct visible light into the optic, and wherein the optic is configured to turn the visible light and direct the visible light through an image-forming light valve and toward the surface.

19. The system of claim 7, wherein the light source comprises a laser configured to raster coherent, image-modulated light into the optic.

12. A touch-sensitive display system configured to detect touch by capturing an image of one or more objects disposed on a touch-sensitive display surface, the system comprising:

an illuminant configured to illuminate the one or more objects from behind the touch-sensitive display surface with light having a median wavelength λ

;

a detector configured to capture the image;

an optic configured to direct to the detector light reflected from the one or more objects and to attenuate a reflection of the light, the optic comprising;

a wedge-shaped light guide having opposing first and second faces and comprising a material having a first refractive index, the first face supporting a cladding layer having a second refractive index less than the first refractive index, a thickness d of the cladding layer given by

13. The touch-sensitive display system of claim 12, wherein the illuminant comprises an infrared light-emitting diode, and the detector comprises an infrared-sensitive camera.

14. The touch-sensitive display system of claim 12, wherein the turning film comprises a plurality of facets oblique to the first face of the wedge-shaped light guide and supporting a reflective coating.

15. A system for displaying a visible image on a surface, the system comprising:

an image-creating subsystem adapted to create the visible image from light from a light source; and

an optic configured to turn and project the light to display the visible image on the surface, the optic comprising;

a wedge-shaped light guide having opposing first and second faces and comprising a material having a first refractive index, the first face supporting a first cladding layer having a second refractive index less than the first refractive index, the second face supporting a second cladding layer having a fourth refractive index less than the first refractive index and nearer to the second refractive index than to the first refractive index; and

a turning film bonded to the cladding layer via an interface layer, the interface layer having a third refractive index matched to the first refractive index, wherein the optic is configured to attenuate a reflection of light having a median wavelength λ and

wherein the thickness d of one or more of the first and the second cladding layers is given by