ENVIRONMENTALLY ISOLATED WAVEGUIDE DISPLAY

• US 20180011324A1
• Filed: 01/12/2016
• Published: 01/11/2018
• Est. Priority Date: 01/12/2015
• Status: Active Grant

• Current Assignee: DigiLens Inc
• Original Assignee: DigiLens Inc
• Inventors: POPOVICH, Milan Momcilo, WALDERN, Jonathan David, GRANT, Alastair John
• Granted Patent: US 10,437,064 B2
• Time in Patent Office: Days
• CPC Class Codes: G02B 2027/0118 comprising devices for improving the contrast of the display / brillance control visibility
• CPC Class Codes: G02B 2027/0125 Field-of-view increase by wavefront division
• CPC Class Codes: G02B 2027/013 comprising a combiner of particular shape, e.g. curvature
• CPC Class Codes: G02B 27/0101 characterised by optical features G02B27/0172 takes precedence
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 6/0016 Grooves, prisms, gratings, scattering particles or rough surfaces
• CPC Class Codes: G02B 6/003 Lens or lenticular sheet or layer
• CPC Class Codes: G02B 6/0035 provided on the surface of the light guide or in the bulk of it
• CPC Class Codes: G02B 6/0045 by shaping at least a portion of the light guide
• CPC Class Codes: G02B 6/0058 varying in density, size, shape or depth along the light guide
• CPC Class Codes: G02B 6/0076 Stacked arrangements of multiple light guides of the same or different cross-sectional area
• CPC Class Codes: G02B 6/34 utilising prism or grating G02B6/293 takes precedence

Abstract

A waveguide display having an input image generator providing image light projected over a field of view; a waveguide having first and second external surfaces; and at least one grating optically coupled to the waveguide for extracting light towards a viewer. The waveguide has a lateral refractive index variation between said external surfaces that prevents any ray propagated within the waveguide from optically interacting with at least one of the external surfaces.

Claims

1. A waveguide display, comprising:

an input image generator providing image light projected over a field of view;

a waveguide having first and second external surfaces; and

at least one grating optically coupled to said waveguide for extracting light from said waveguide towards a viewer of said display,

wherein said waveguide has a lateral refractive index variation between said external surfaces that prevents rays propagating within said waveguide from optically interacting with at least one of said external surfaces.

2. The apparatus of claim 1 wherein said waveguide contains a GRIN medium wherein said grating is disposed in proximity to one of said external surfaces.

4. The apparatus of claim 1 wherein said waveguide contains a GRIN medium, wherein said grating is a surface relief structure formed on one of said external surfaces.

5. The apparatus of claim 1 wherein said waveguide comprises a first waveguide portion containing a GRIN medium abutting a second waveguide portion operating in TIR and containing at least one grating for extracting light from said second waveguide portion towards a viewer of said display.

6. The apparatus of claim 1 wherein said waveguide further comprises an input grating.

7. The apparatus of claim 1 immersed in air.

8. The apparatus of claim 1 providing one of a HUD, HMD or a light field display.

9. The apparatus of claim 1 wherein said waveguide is curved.

10. The apparatus of claim 1 wherein said waveguide comprises at least one GRIN waveguide portion optically coupled to at least one TIR waveguide portion, each said TIR waveguide portion containing at least one grating.

11. The apparatus of claim 1 wherein said waveguide comprises a stack of GRIN waveguides optically coupled to a stack of TIR waveguides, each said TIR waveguide containing at least one grating.

12. The apparatus of claim 1 wherein said waveguide is immersed in a low refractive index external medium and comprises a high refractive index core sandwiched by a low refractive index clad layer and at least one grating layer, wherein TIR takes place between the interface of said core layer and said grating layer and the interface of said grating layer and said external medium.

13. The apparatus of claim 12 wherein said core and said grating layer have substantially same average refractive index.

14. The apparatus of claim 12 wherein said core has a refractive index greater than said grating layer average index.

15. The apparatus of claim 12 further comprising low refractive index layers overlaying at least one of said grating layer and said low refractive index clad layer.

16. The apparatus of claim 12 wherein said grating layer comprises a grating sandwiched by transparent substrates, said grating layer and said substrates having similar refractive indices.

17. The apparatus of claim 1 wherein said grating layer comprises an input grating and an extraction grating.

18. The apparatus of claim 1 further comprising a beamsplitter layer.

19. The apparatus of claim 1 wherein said image light is collimated.

20. The apparatus of claim 1 wherein said grating is one of a Bragg Grating, a surface relief grating or a switchable Bragg grating recorded in a HPDLC material, a uniform modulation HPDLC material or a reverse mode HPDLC material.

3. The apparatus of claim wherein said waveguide contains a GRIN medium, wherein said grating is disposed within said GRIN medium.