Waveguides with extended field of view

• US 9,791,703 B1
• Filed: 04/13/2016
• Issued: 10/17/2017
• Est. Priority Date: 04/13/2016
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Inventors: Vallius, Tuomas, Tervo, Jani
• Primary Examiner(s): Ben, Loha
• Application Number:
  US15/097,661
• Publication Number:
  US 20170299864A1
• Time in Patent Office: 552 Days
• Field of Search: 359630, 359632, 359558, 359566, 359567, 385 10, 385 31, 385 37, 345633
• CPC Class Codes: G02B 2005/1804 Transmission gratings
• CPC Class Codes: G02B 2027/0123 comprising devices increasing the field of view
• 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 2027/0174 holographic
• CPC Class Codes: G02B 27/0081 with means for altering, e.g. enlarging, the entrance or exit pupil
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 27/4205 having a diffractive optical element [DOE] contributing to image formation, e.g. whereby modulation transfer function MTF or optical aberrations are relevant
• CPC Class Codes: G02B 27/44 Grating systems; Zone plate systems G02B27/46 takes precedence
• CPC Class Codes: G02B 30/35 using reflective optical elements in the optical path between the images and the observer
• CPC Class Codes: G02B 5/18 Diffraction gratings holographic optical elements G02B5/32, G03H; integrally combined with optical fibres G02B6/02057; for coupling light guides G02B6/34; integrally combined with optical integrated light guides G02B6/12; grating systems G02B27/44
• CPC Class Codes: G02B 5/1814 structurally combined with one or more further optical elements, e.g. lenses, mirrors, prisms or other diffraction gratings G02B5/189 takes precedence
• CPC Class Codes: G02B 5/1819 Plural gratings positioned on the same surface, e.g. array of gratings plural diffractive elements positioned sequentially along the optical path G02B27/4272
• CPC Class Codes: G02B 6/0026 Wavelength selective element, sheet or layer, e.g. filter or grating
• CPC Class Codes: G02B 6/005 provided by one optical element, or plurality thereof, placed on the light output side of the light guide
• CPC Class Codes: G02F 1/292 by controlled diffraction or phased-array beam steering controlled diffraction for optical switching G02F1/31
• CPC Class Codes: G02F 1/295 Analog deflection from or in an optical waveguide structure]
• CPC Class Codes: H04N 13/332 Displays for viewing with the aid of special glasses or head-mounted displays [HMD]
• CPC Class Codes: H04N 13/344 with head-mounted left-right displays

Abstract

An input-coupler of an optical waveguide couples light corresponding to the image and having a corresponding FOV into the optical waveguide, and the input-coupler splits the FOV of the image coupled into the optical waveguide into first and second portions by diffracting a portion of the light corresponding to the image in a first direction toward a first intermediate-component, and diffracting a portion of the light corresponding to the image in a second direction toward a second intermediate-component. An output-coupler of the waveguide combines the light corresponding to the first and second portions of the FOV, and couples the light corresponding to the combined first and second portions of the FOV out of the optical waveguide so that the light corresponding to the image and the combined first and second portions of the FOV is output from the optical waveguide. The intermediate-components and the output-coupler also provide for pupil expansion.

Claims

1. An apparatus for use in replicating an image associated with an input-pupil to an output-pupil, the apparatus comprising:

an optical waveguide including an input-coupler, first and second intermediate-components and an output-coupler;

the input-coupler comprising a diffraction grating and configured to;

couple light corresponding to the image associated with the input-pupil, and having a corresponding field of view (FOV), into the optical waveguide;

diffract a portion of the light corresponding to the image in a first direction toward the first intermediate-component such that a first portion of the FOV travels through the optical waveguide from the input-coupler to the first intermediate-component; and

diffract a portion of the light corresponding to the image in a second direction toward the second intermediate-component such that a second portion of the FOV travels through the optical waveguide from the input-coupler to the second intermediate-component;

wherein the first and second directions differ from one another; and

wherein the first and second portions of the FOV differ from one another;

the first intermediate-component configured to diffract light corresponding to the first portion of the FOV, which travels through the optical waveguide from the input-coupler to the first intermediate-component, toward the output coupler;

the second intermediate-component configured to diffract light corresponding to the second portion of the FOV, which travels through the optical waveguide from the input-coupler to the second intermediate-component, toward the output coupler; and

the output-coupler configured to;

combine the light corresponding to the first and second portions of the FOV, which travel through the optical waveguide from the first and second intermediate-components to the output-coupler; and

couple the light corresponding to the combined first and second portions of the FOV out of the optical waveguide so that the light corresponding to the image and the combined first and second portions of the FOV is output from the optical waveguide and viewable from the output-pupil.

2. The apparatus of claim 1, wherein:

the input-coupler, by diffracting the portion of the light corresponding to the image in the first direction toward the first intermediate-component, and diffracting the portion of the light corresponding to the image in the second direction toward the second intermediate-component, splits the FOV into the first and second portions;

the output-coupler, by combining the light corresponding to the first and second portions of the FOV, unifies the FOV that was split by the input-coupler; and

a unified FOV associated with the light coupled out of the optical waveguide, by the output-coupler, is greater than a maximum FOV that each of the first and second intermediate-components can support on their own.

3. The apparatus of claim 1, wherein:

each of the first and second intermediate-components is configured to perform one of horizontal or vertical pupil expansion; and

the output-coupler is configured to perform the other one of horizontal or vertical pupil expansion.

4. The apparatus of claim 1, wherein:

one of the first and second directions comprises a leftward direction; and

the other one of the first and second directions comprises a rightward direction.

5. The apparatus of claim 1, wherein the first portion of the FOV partially overlaps with the second portion of the FOV.

6. The apparatus of claim 1, wherein:

the optical waveguide includes a first major surface and a second major surface opposite to the first major surface; and

the diffraction grating of the input-coupler comprises a surface relief grating (SRG) that is located in or on a single one of the first and second major surfaces of the optical waveguide.

7. The apparatus of claim 1, wherein:

the optical waveguide includes a first major surface and a second major surface opposite to the first major surface; and

the diffraction grating of the input-coupler comprises;

a first surface relief grating (SRG) that is located in or on one of the first and second major surfaces of the optical waveguide and is configured to diffract the light corresponding to the first portion of the FOV in the first direction toward the first intermediate-component; and

a second SRG that is located in or on the other one of the first and second major surfaces of the optical waveguide and is configured to diffract the light corresponding to the second portion of the FOV in the second direction toward the second intermediate-component.

8. The apparatus of claim 1, further comprising one or more further intermediate-components, which is/are in addition to the first and second intermediate-components, wherein:

the input-coupler is also configured to diffract light corresponding to at least a portion of the FOV to each of the one or more further intermediate-components; and

the one or more further intermediate-components is/are each configured to diffract light, corresponding to at least a portion of the FOV that is incident on the further intermediate-component, toward the output-coupler.

9. The apparatus of claim 1, further comprising:

a display engine configured to produce an image;

wherein the light corresponding to the image that is coupled into the optical waveguide by the input-coupler comprises the light corresponding to the image that is produced by the display engine.

10. The apparatus of claim 1, wherein each of the input-coupler, the first and second intermediate-components and the output-coupler comprises a separate diffractive optical element (DOE).

11. The apparatus of claim 1, wherein the apparatus is part of a head-mounted display (HMD) or a heads-up display (HUD).

12. A method for using an optical waveguide to replicate an image associated with an input-pupil to an output-pupil, the method comprising:

coupling light corresponding to the image associated with the input-pupil, and having a corresponding field of view (FOV), into the optical waveguide;

splitting the FOV of the image coupled into the optical waveguide into first and second portions by diffracting a portion of the light corresponding to the image in a first direction, and diffracting a portion of the light corresponding to the image in a second direction, wherein the first and second directions differ from one another, and wherein the first and second portions of the FOV differ from one another; and

after the light corresponding to the image has travelled through portions of the optical waveguide by way of total internal reflection, combining the light corresponding to the first and second portions of the FOV, and coupling the light corresponding to the combined first and second portions of the FOV out of the optical waveguide so that the light corresponding to the image and the combined first and second portions of the FOV is output from the optical waveguide and viewable from the output-pupil.

13. The method of claim 12, wherein:

one of the first and second directions comprises a leftward direction; and

the other one of the first and second directions comprises a rightward direction.

14. The method of claim 12, wherein:

the coupling light corresponding to the image associated with the input-pupil, and having the corresponding FOV, into the optical waveguide, and the splitting the FOV of the image coupled into the optical waveguide into the first and second portions, by diffracting the portion of the light corresponding to the image in the first direction, and diffracting the portion of the light corresponding to the image in the second direction, are performed by an input-coupler of the optical waveguide;

prior to the combining the light corresponding to the first and second portions of the FOV to thereby unify the FOV that was split, transferring the light corresponding to the first and second portions of the FOV from the input-coupler, respectively, to first and second intermediate-components of the optical waveguide by way of total internal reflection (TIR), and using the first and second intermediate-components of the optical waveguide to perform one of horizontal or vertical pupil expansion; and

the combining the light corresponding to the first and second portions of the FOV, and the coupling the light corresponding to the combined first and second portions of the FOV out of the optical waveguide, are performed by an output-coupler of the optical waveguide.

15. The method of claim 14, further comprising, using the output-coupler to perform the other one of horizontal or vertical pupil expansion.

16. A head-mounted display (HMD) or a heads-up display (HUD) system, comprising:

a display engine configured to produce an image;

an optical waveguide including an input-coupler, first and second intermediate-components, and an output-coupler;

the input-coupler configured to;

couple light corresponding to the image produced by the display engine, and having a corresponding field of view (FOV), into the optical waveguide; and

split the FOV of the image coupled into the optical waveguide into first and second portions by diffracting a portion of the light corresponding to the image in a first direction toward the first intermediate-component, and diffracting a portion of the light corresponding to the image in a second direction toward the second-intermediate component, wherein the first and second directions differ from one another, and wherein the first and second portions of the FOV differ from one another; and

the output-coupler configured to combine the light corresponding to the first and second portions of the FOV, which travel from the first and second intermediate-components to the output-coupler by way of total internal reflection, and couple the light corresponding to the combined first and second portions of the FOV out of the optical waveguide so that the light corresponding to the image and having the combined first and second portions of the FOV is output from the optical waveguide.

17. The system of claim 16, wherein:

the input-coupler, by diffracting the portion of the light corresponding to the image in the first direction toward the first intermediate-component, and diffracting the portion of the light corresponding to the image in the second direction toward the second intermediate-component, splits the FOV into the first and second portions;

the output-coupler, by combining the light corresponding to the first and second portions of the FOV, unifies the FOV that was split by the input-coupler; and

a unified FOV associated with the light coupled out of the optical waveguide, by the output-coupler, is greater than a maximum FOV that each of the first and second intermediate-components can support on their own.

18. The system of claim 16, wherein the first portion of the FOV partially overlaps with the second portion of the FOV.

19. The system of claim 16, wherein:

the optical waveguide includes a first major surface and a second major surface opposite to the first major surface; and

a diffraction grating of the input-coupler comprises a surface relief grating (SRG) that is located in or on a single one of the first and second major surfaces of the optical waveguide.

20. The system of claim 16, wherein:

the optical waveguide includes a first major surface and a second major surface opposite to the first major surface; and

a diffraction grating of the input-coupler comprises;

a first surface relief grating (SRG) that is located in or on one of the first and second major surfaces of the optical waveguide and that is configured to diffract the light corresponding to the first portion of the FOV in the first direction toward the first intermediate-component; and

a second SRG that is located in or on the other one of the first and second major surfaces of the optical waveguide and that is configured to diffract the light corresponding to the second portion of the FOV in the second direction toward the second intermediate-component.