Apparatus for providing waveguide displays with two-dimensional pupil expansion

• US 10,690,916 B2
• Filed: 10/04/2016
• Issued: 06/23/2020
• Est. Priority Date: 10/05/2015
• Status: Active Grant

• Current Assignee: DigiLens Inc
• Original Assignee: DigiLens Inc
• Inventors: Popovich, Milan Momcilo, Waldern, Jonathan David, Grant, Alastair John
• Primary Examiner(s): Shankar, Vijay
• Application Number:
  US15/765,243
• Publication Number:
  US 20180284440A1
• Time in Patent Office: 1,358 Days
• CPC Class Codes: G02B 2027/0114 comprising dichroic elements
• CPC Class Codes: G02B 2027/0125 Field-of-view increase by wavefront division
• CPC Class Codes: G02B 2027/0187 slaved to motion of at least a part of the body of the user, e.g. head, eye
• CPC Class Codes: G02B 27/0081 with means for altering, e.g. enlarging, the entrance or exit pupil
• CPC Class Codes: G02B 27/0093 with means for monitoring data relating to the user, e.g. head-tracking, eye-tracking
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 27/0179 Display position adjusting means not related to the information to be displayed
• CPC Class Codes: G02B 5/1866 Transmission gratings characterised by their structure, e.g. step profile, contours of substrate or grooves, pitch variations, materials G02B5/1809, G02B5/1828, G02B5/1833, G02B5/1838 and G02B5/1847 take precedence
• CPC Class Codes: G02B 6/0016 Grooves, prisms, gratings, scattering particles or rough surfaces
• CPC Class Codes: G02B 6/0035 provided on the surface of the light guide or in the bulk of it
• CPC Class Codes: G02B 6/0076 Stacked arrangements of multiple light guides of the same or different cross-sectional area
• CPC Class Codes: G02F 1/292 by controlled diffraction or phased-array beam steering controlled diffraction for optical switching G02F1/31

Abstract

An optical display comprises: a first waveguide comprising a first surface and a second surface, an input coupler, a fold grating, and an output grating. The input coupler receives collimated first wavelength light from an Input Image Node causes the light to travel within the first waveguide via total internal reflection between the first surface and the second surface to the fold grating. The fold grating provides pupil expansion in a first direction directs the light to the output grating via total internal reflection between the first surface and the second surface. The output grating provides pupil expansion in a second direction different than the first direction and causes the light to exit the first waveguide from the first surface or the second surface. At least one of the input coupler, fold grating and output grating is a rolled k-vector grating, and the fold grating is a dual interaction grating.

Claims

1. An optical display, comprising:

a first waveguide having a first surface and a second surface;

an input coupler;

a fold grating;

an output grating; and

an input image node (IIN),

wherein said input coupler is configured to receive collimated first wavelength image modulated light and to cause said first wavelength image modulated light to travel within the first waveguide via total internal reflection between said first surface and said second surface to the fold grating,

wherein said fold grating is configured to provide pupil expansion in a first direction and to direct said first wavelength image modulated light to the output grating via total internal reflection between the first surface and the second surface,

wherein said output grating is configured to provide pupil expansion in a second direction different than said first direction and to cause said first wavelength image modulated light to exit said first waveguide from said first surface or said second surface,

wherein at least one of said input coupler, said fold grating or said output grating is a rolled k-vector grating, and

wherein said first wavelength image modulated light undergoes a dual interaction with said fold grating.

2. The optical display of claim 1, wherein said IIN comprises a light source, a microdisplay for displaying image pixels and collimation optics, and wherein said IIN projects the image displayed on said microdisplay such that each image pixel is converted into a unique angular direction within said first waveguide.

3. The optical display of claim 1, wherein at least one of said fold and output gratings is switchable between a diffracting and non-diffracting state.

4. The optical display of claim 1, further comprising a second waveguide comprising a first surface and a second surface, an input coupler, a fold grating, and an output grating, wherein the input coupler of the second waveguide is configured to receive collimated second wavelength image modulated light from said IIN.

5. The optical display of claim 1, wherein at least one of said input coupler, said fold grating, and said output grating is a liquid crystal-based grating.

6. The optical display of claim 1, wherein said input coupler is one of a grating or a prism.

7. The optical display of claim 1, wherein said first direction is orthogonal to said second direction.

8. The optical display of claim 1, wherein said first direction is horizontal and said second direction is vertical.

9. The optical display of claim 1, further comprising an eye tracker.

10. The optical display of claim 1, further comprising a dynamic focus lens disposed in said IIN.

11. The optical display of claim 1, further comprising a dynamic focus lens disposed in proximity to the first or second surface of said first waveguide.

12. The optical display of claim 1, wherein said first waveguide further comprises a first optical interface said IIN further comprises a second optical interface wherein said first and second optical interface can be decoupled by one of a mechanical mechanism or a magnetic mechanism.

13. The optical display of claim 12, wherein said first waveguide is disposable.

14. The optical display of claim 1, wherein said first surface and said second surface are planar surfaces.

15. The optical display of claim 1, wherein said first surface and said second surface are curved.

16. The optical display of claim 1, wherein said IIN comprises a laser scanner.

17. The optical display of claim 1, wherein said optical display provides one of a HMD, a HUD, an eye-slaved display, a dynamic focus display or a light field display.

18. The optical display of claim 1, wherein at least one of said input coupler, fold grating and output grating multiplexes at least one of color or angle.

19. The optical display of claim 1, further comprising a beam homogenizer.

20. The optical display of claim 1, wherein said optical display includes at least one optical traversing a gradient index image transfer waveguide.

21. The optical display of claim 4 further comprising a dichroic filter disposed between the input grating regions of said first and second waveguides.

22. The optical display of claim 2 wherein said IIN further comprises a spatially-varying numerical aperture component for providing a numerical aperture variation along a direction corresponding to a field of view coordinate diffracted by said input coupler.

23. The optical display of claim 22 wherein said spatially-varying numerical aperture component has at least one of diffractive, birefringent, refracting or scattering characteristics.

24. The optical display of claim 22 wherein said field of view coordinate is a horizontal field of view of the optical display.

25. The optical display of claim 2 wherein a spatially varying-numerical aperture is provided by tilting a stop plane such that its normal vector is aligned parallel to a highest display field angle in the stop plane containing the field of view coordinate diffracted by said input coupler.