Curved waveguide combiner for head-mounted and helmet-mounted displays (HMDS), a collimated virtual window, or a head up display (HUD)

Patent metadata

Field	Value
Publication number	US-9733475-B1
Application number	US-201414479677-A
Country	US
Kind code	B1
Filing date	Sep 8, 2014
Priority date	Sep 8, 2014
Publication date	Aug 15, 2017
Grant date	Aug 15, 2017

Abstract

A head mounted or helmet mounted display (HMD), head up display (HUD, or collimated virtual window can be used in various applications including but not limited to avionic applications. The HMD, HUD, or collimated virtual window can include a cylindrical, elliptical, or curved substrate waveguide combiner. The cylindrical or curved substrate waveguide combiner can be used with a projector which provides pre-aberrated light. The cylindrical substrate waveguide combiner provides collimated light to a user with reduced wavefront errors.

First claim

What is claimed is:

1. A head-mounted or helmet-mounted display (HMD) for use with an image source, the HMD comprising:
an asymmetric projector; and
a curved substrate waveguide optically coupled to the asymmetric projector and positioned as a combiner such that light from the asymmetric projector enters the curved substrate waveguide, propagates by total internal reflection along the curved substrate waveguide in a direction substantially parallel to a single vertical axis of the curved substrate waveguide, and exits the curved substrate waveguide as collimated light toward a user, the curved substrate waveguide having an inside surface curved about the single vertical axis at a first fixed radius and an outside surface curved about the single vertical axis at a second fixed radius, wherein the single vertical axis is the axis of curvature for both the inside surface and the outside surface; and
wherein the asymmetric projector is configured to pre-aberrate the light to reduce a wavefront error due to a curved shape of the curved substrate waveguide.

2. The HMD of claim 1 , wherein the HMD provides a projected pupil, the projected pupil is provided to an imaginary stop in a plane including the single vertical axis and being equidistant from a front surface of the asymmetric projector.

3. The HMD of claim 1 , wherein the asymmetric projector comprises a micro liquid crystal display.

4. The HMD of claim 1 , wherein the curved substrate waveguide is symmetric about eye positions.

5. The HMD of claim 1 , wherein the light travels by total internal reflection in the curved substrate waveguide substantially parallel to the single vertical axis from a top to a bottom.

6. The HMD of claim 1 , wherein light from the asymmetric projector enters from a top or bottom edge of the curved substrate waveguide and leaves the curved substrate waveguide on the inside surface of the curved substrate waveguide.

7. The HMD of claim 1 , wherein the asymmetric projector includes an anamorphic lens.

8. The HMD of claim 1 , wherein the wavefront error is reduced to substantially zero across a vertical and horizontal field of view.

9. The HMD of claim 1 , wherein the light is input into the curved substrate waveguide via diffraction.

10. A method of providing information to a user using a head-mounted or helmet-mounted display, a head up display, or collimated virtual display system, the method comprising:
providing pre-aberrated light to a curved substrate waveguide combiner, the curved substrate waveguide combiner having an inside surface curved about the single vertical axis at a first fixed radius and an outside surface curved about the single vertical axis at a second fixed radius, wherein the single vertical axis is the axis of curvature for both the inside surface and the outside surface, wherein the curved substrate waveguide combiner has an input and an output and is optically coupled to an asymmetric projector configured to provide the pre-aberrated light to the input such that the pre-aberrated light from the asymmetric projector enters the curved substrate waveguide;
providing the pre-aberrated light from the input of the curved substrate waveguide combiner to the output of the curved substrate waveguide combiner, wherein the pre-aberrated light propagates by total internal reflection along the curved substrate waveguide combiner in a direction substantially parallel to the single vertical axis of the curved substrate waveguide combiner; and
ejecting light from the curved substrate waveguide combiner at the output of the curved substrate waveguide combiner as collimated light toward the user with reduced wavefront error due to the use of the pre-aberrated light.

11. The method of claim 10 , wherein the wavefront error is a function of a number of bounces in the curved substrate waveguide combiner.

12. The method of claim 10 , wherein the curved substrate waveguide combiner is cylindrically curved.

13. The method of claim 10 , wherein the input and output are diffractive.

14. The method of claim 10 , wherein the pre-aberrated light is pre-aberrated according to a two dimensional function.

15. A head-mounted or helmet-mounted display, a head up display, or collimated virtual display system, comprising:
a curved waveguide combiner having an input grating and an output grating, wherein light travels by total internal reflection from a top to a bottom of the curved waveguide combiner in a direction substantially parallel to a single vertical axis, the curved waveguide combiner is curved about the single vertical axis and provides collimated light at the output grating, the curved waveguide combiner having an inside surface curved about the single vertical axis at a first fixed radius and an outside surface curved about the single vertical axis at a second fixed radius, wherein the single vertical axis is the axis of curvature for both the inside surface and the outside surface, wherein the curved waveguide combiner is configured such that the light enters the curved waveguide combiner at the input grating and propagates by total internal reflection along the curved waveguide combiner in a direction substantially parallel to the single vertical axis of the curved waveguide combiner, and exits the curved waveguide combiner at the output grating as collimated light toward a user; and
an asymmetric optical system optically coupled to the curved waveguide combiner and providing the light to the input grating, wherein the asymmetric optical system is configured to reduce wavefront errors associated with the curved waveguide combiner.

16. The system of claim 15 , wherein the wavefront errors are a function of a number of bounces in the curve waveguide combiner.

17. The system of claim 15 , wherein the asymmetric optical system is pre-aberrated across the vertical and horizontal field of view of the curved waveguide combiner.

18. The system of claim 15 , wherein the asymmetric optical system comprises an anamorphic lens.

19. The system of claim 15 wherein the curved waveguide combiner is a face shield.

20. The system of claim 15 wherein the curved waveguide combiner is a face shield.

Assignees

• Brown Robert D
• Stanley James H
• Rockwell Collins Inc

Inventors

• Brown Robert D
• Stanley James H

Classifications

• G02B2027/013

  comprising a combiner of particular shape, e.g. curvature · CPC title

• G02B27/0172

  characterised by optical features · CPC title

• G02B27/0081

  with means for altering, e.g. enlarging, the entrance or exit pupil · CPC title

• G02B2027/0174

  holographic · CPC title

• G02B6/003

  Lens or lenticular sheet or layer · CPC title