Wide field-of-view virtual image projector

• US 10,107,994 B2
• Filed: 03/09/2015
• Issued: 10/23/2018
• Est. Priority Date: 06/12/2012
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Inventors: Travis, Adrian R. L.
• Primary Examiner(s): Thomas, Brandi
• Application Number:
  US14/641,831
• Publication Number:
  US 20150177497A1
• Time in Patent Office: 1,324 Days
• Field of Search: 359619-630
• CPC Class Codes: G02B 13/06 Panoramic objectives; So-called "sky lenses" including panoramic objectives having reflecting surfaces
• CPC Class Codes: G02B 2027/0125 Field-of-view increase by wavefront division
• CPC Class Codes: G02B 2027/0178 Eyeglass type eyeglass details G02C
• CPC Class Codes: G02B 27/0081 with means for altering, e.g. enlarging, the entrance or exit pupil
• CPC Class Codes: G02B 27/017 Head mounted
• CPC Class Codes: G02B 27/0172 characterised by optical features
• 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 6/0028 Light guide, e.g. taper
• CPC Class Codes: G02B 6/0033 Means for improving the coupling-out of light from the light guide
• CPC Class Codes: G02B 6/34 utilising prism or grating G02B6/293 takes precedence
• CPC Class Codes: G02B 6/42 Coupling light guides with opto-electronic elements
• CPC Class Codes: G02B 6/4298 coupling with non-coherent light sources and/or radiation detectors, e.g. lamps, incandescent bulbs, scintillation chambers

Abstract

A wide field-of-view virtual image projector includes a rod light guide that is embossed with at least a first diffraction grating and a second diffraction grating that is substantially parallel to the first diffraction grating. The first diffraction grating is configured to receive a first light ray, and to project first diffracted light rays from the rod light guide at a first range of angles. The second diffraction grating is configured to receive a second light ray, and to project second diffracted light rays from the rod light guide at a second range of angles. The virtual image projector further includes a slab light guide configured to receive the first diffracted light rays and the second diffracted light rays, and to diffract the first diffracted light rays and the second diffracted light rays out of the slab light guide to generate a virtual image with a wide field-of view.

Claims

1. A method comprising:

receiving data corresponding to a virtual image;

controlling an illuminator to inject first light rays into a first diffraction grating of a rod light guide effective to diffract the first light rays out of the rod light guide at a first range of angles and into a slab light guide; and

controlling the illuminator to inject second light rays into a second diffraction grating of the rod light guide effective to diffract the second light rays out of the rod light guide at a second range of angles and into the slab light guide, the first diffraction grating substantially parallel to the second diffraction grating on a first surface of the rod light guide, the first diffraction grating having a first spatial frequency that is different than a second spatial frequency of the second diffraction grating, the first spatial frequency causing the first diffraction grating to project the first diffracted light rays at the first range of angles, and the second spatial frequency causing the second diffraction grating to project the second diffracted light rays at the second range of angles, and the slab light guide configured to generate the virtual image.

2. The method as described in claim 1, wherein the slab light guide is configured to generate the virtual image with a field-of-view that is equal to the sum of the first range of angles and the second range of angles.

3. The method as described in claim 1, wherein the first range of angles is different than the second range of angles.

4. The method as described in claim 1, further comprising:

controlling the illuminator to inject third light rays into a third diffraction grating of the rod light guide effective to diffract the third light rays out of the rod light guide at a third range of angles and into the slab light guide.

5. The method as described in claim 4, further comprising:

controlling the illuminator to inject fourth light rays into a fourth diffraction grating of the rod light guide effective to diffract the fourth light rays out of the rod light guide at a fourth range of angles and into the slab light guide.

6. The method as described in claim 5, wherein the slab light guide generates the virtual image with a field-of-view that is equal to the sum of the first range of angles, the second range of angles, the third range of angles, and the fourth range of angles.

7. The method as described in claim 5, wherein:

the first range of angles is approximately −

60 degrees to −

30 degrees, the second range of angles is approximately −

30 degrees to 0 degrees, the third range of angles is approximately 0 degrees to 30 degrees, the fourth range of angles is approximately 30 degrees to 60 degrees.

8. The method as described in claim 1, wherein the slab light guide is configured to generate the virtual image with a field-of-view that is approximately 120 degrees.

9. The method as described in claim 1, wherein the slab light guide is embossed with a third diffraction grating that is substantially perpendicular to the first diffraction grating and the second diffraction grating, the third diffraction grating configured to cause the first diffracted light rays and the second diffracted light rays to be projected out of the slab light guide to generate the virtual image.

10. The method as described in claim 1, wherein the slab light guide is configured with a partially-reflecting mirror that is configured to reflect a portion, and transmit another portion, of each of the first diffracted light rays and the second diffracted light rays.

11. One or more computer-readable storage media comprising instructions stored thereon that, responsive to execution by one or more processors, perform operations comprising:

receiving data corresponding to a virtual image;

controlling an illuminator to inject first light rays into a first diffraction grating of a rod light guide effective to diffract the first light rays out of the rod light guide at a first range of angles and into a slab light guide;

controlling the illuminator to inject second light rays into a second diffraction grating of the rod light guide effective to diffract the second light rays out of the rod light guide at a second range of angles and into the slab light guide, the first diffraction grating substantially parallel to the second diffraction grating on a first surface of the rod light guide, the first diffraction grating having a first spatial frequency that is different than a second spatial frequency of the second diffraction grating, the first spatial frequency causing the first diffraction grating to project the first diffracted light rays at the first range of angles, and the second spatial frequency causing the second diffraction grating to project the second diffracted light rays at the second range of angles, and the slab light guide configured to generate the virtual image.

12. The one or more computer-readable storage media of claim 11, wherein the slab light guide is configured to generate the virtual image with a field-of-view that is equal to the sum of the first range of angles and the second range of angles.

13. The one or more computer-readable storage media of claim 11, wherein the first range of angles is different than the second range of angles.

14. The one or more computer-readable storage media of claim 11, wherein the operations further comprise controlling the illuminator to inject third light rays into a third diffraction grating of the rod light guide effective to diffract the third light rays out of the rod light guide at a third range of angles and into the slab light guide.

15. The one or more computer-readable storage media of claim 14, wherein the operations further comprise controlling the illuminator to inject fourth light rays into a fourth diffraction grating of the rod light guide effective to diffract the fourth light rays out of the rod light guide at a fourth range of angles and into the slab light guide.

16. The one or more computer-readable storage media of claim 15, wherein the slab light guide generates the virtual image with a field-of-view that is equal to the sum of the first range of angles, the second range of angles, the third range of angles, and the fourth range of angles.

17. The one or more computer-readable storage media of claim 15, wherein:

the first range of angles is approximately −

60 degrees to −

30 degrees, the second range of angles is approximately −

30 degrees to 0 degrees, the third range of angles is approximately 0 degrees to 30 degrees, the fourth range of angles is approximately 30 degrees to 60 degrees.

18. The one or more computer-readable storage media of claim 11, wherein the slab light guide is embossed with a third diffraction grating that is substantially perpendicular to the first diffraction grating and the second diffraction grating, the third diffraction grating configured to cause the first diffracted light rays and the second diffracted light rays to be projected out of the slab light guide to generate the virtual image.

19. The one or more computer-readable storage media of claim 11, wherein the slab light guide is configured to generate the virtual image with a field-of-view that is approximately 120 degrees.

20. The one or more computer-readable storage media of claim 11, wherein the slab light guide is configured with a partially-reflecting mirror that is configured to reflect a portion, and transmit another portion, of each of the first diffracted light rays and the second diffracted light rays.