Optical systems with multi-layer holographic combiners

Patent metadata

Field	Value
Publication number	US-11740460-B2
Application number	US-201916688831-A
Country	US
Kind code	B2
Filing date	Nov 19, 2019
Priority date	Nov 29, 2018
Publication date	Aug 29, 2023
Grant date	Aug 29, 2023

Abstract

An electronic device may include a display module that generates image light and an optical system that redirects the light towards an eye box. The optical system may have first hologram structures that replicate the light over multiple output angles onto second hologram structures. The second hologram structures may focus the replicated light onto the eye box. If desired, the device may include an image sensor. The first and second hologram structures may include transmission and/or reflection holograms. The optical system may redirect a first portion of the light to the eye box and a second portion of the light to the sensor. The sensor may generate image data based on the second portion of the light. Control circuitry may compensate for distortions in the first portion of the light by performing feedback adjustments to the display module based on distortions in the image data.

First claim

What is claimed is:

1. An electronic device comprising:
a projector configured to generate light;
first holograms; and
second holograms, wherein the first holograms are configured to receive the light, the first holograms are configured to replicate the light by diffracting the light, and the second holograms are configured to focus, onto a focal point, the light diffracted by the first holograms, the light being Bragg-matched to the first holograms at input angles from the projector and output angles towards the second holograms.

2. The electronic device of claim 1 , wherein the first holograms comprise transmission holograms.

3. The electronic device of claim 2 , wherein the second holograms comprise reflection holograms.

4. The electronic device of claim 3 , wherein the transmission holograms comprise point-to-plane-wave transmission holograms and wherein the reflection holograms comprise plane-wave-to-point reflection holograms.

5. The electronic device of claim 3 , wherein the transmission holograms comprise plane-wave-to-plane-wave transmission holograms and wherein the reflection holograms comprise plane-wave-to-point reflection holograms.

6. The electronic device of claim 3 , wherein the transmission holograms comprise point-to-nearly-plane-wave transmission holograms and wherein the reflection holograms comprise nearly-plane-wave-to-point reflection holograms.

7. The electronic device of claim 3 , wherein the transmission holograms comprise a first transmission hologram configured to diffract the light from a first incident angle at a first output angle towards the reflection holograms, and wherein the transmission holograms comprise a second transmission hologram configured to diffract the light from the first incident angle at a second output angle towards the reflection holograms.

8. The electronic device of claim 7 , wherein the first transmission hologram is configured to diffract the light from a second incident angle at the first output angle towards the reflection holograms, wherein the second transmission hologram is configured to diffract the light from the second incident angle at the second output angle towards the reflection holograms, wherein the reflection holograms comprise a first region having a first reflection hologram configured to diffract the light that was diffracted by the first transmission hologram at a third output angle towards the focal point and a second reflection hologram configured to diffract the light that was diffracted by the second transmission hologram at the third output angle towards the focal point, and wherein the reflection holograms comprise a second region having a third reflection hologram configured to diffract the light that was diffracted by the first transmission hologram at a fourth output angle towards the focal point and a fourth reflection hologram configured to diffract the light that was diffracted by the second transmission hologram at the fourth output angle towards the focal point.

9. The electronic device of claim 1 , further comprising:
a substrate having opposing first and second surfaces, wherein the first holograms are mounted to the first surface and the second holograms are mounted to the second surface;
a first dielectric cover layer over the first holograms; and
a second dielectric cover layer over the second holograms.

10. The electronic device of claim 1 , wherein the first and second holograms each have a non-zero physical curvature and wherein the first holograms are located within 8 mm of the second holograms.

11. The electronic device of claim 1 , wherein the second holograms are provided with an optical power that configures the second holograms to mitigate aberrations associated with the projector.

12. The electronic device of claim 11 , wherein the first holograms are provided with an additional optical power that configures the first holograms to mitigate the aberrations associated with the projector.

13. The electronic device of claim 11 , wherein the second holograms are configured to provide more optical power to the replicated light at a larger diffraction angle from the first holograms than to the replicated light at a smaller diffraction angle from the first holograms.

14. The electronic device of claim 1 , wherein the first holograms comprise a first film having a first set of holograms configured to diffract light of a first wavelength and a second film having a second set of holograms configured to diffract light of a second wavelength.

15. The electronic device of claim 1 , wherein the first holograms comprise a medium having a first set of holograms configured to diffract light of a first wavelength and a second set of holograms that is superimposed with the first set of holograms in the medium and that is configured to diffract light of a second wavelength.

16. The electronic device of claim 1 , wherein the optical system comprises an optical combiner configured to combine the light with real world light.

17. The electronic device of claim 1 , wherein the first holograms comprise transmission holograms and the second holograms comprise reflection holograms, further comprising:
a substrate having opposing first and second surfaces, wherein the first holograms are mounted to the first surface and the second holograms are mounted to the second surface;
a first dielectric cover layer over the first holograms; and
a second dielectric cover layer over the second holograms, wherein the second holograms are configured to provide more optical power to the replicated light at a larger diffraction angle from the first holograms than to the replicated light at a smaller diffraction angle from the first holograms, wherein the first holograms comprise a first film having a first set of holograms configured to diffract light of a first wavelength and a second film having a second set of holograms configured to diffract light of a second wavelength.

18. The electronic device of claim 1 , wherein the first holograms comprise transmission holograms, the second holograms comprise reflection holograms, further comprising:
a substrate having opposing first and second surfaces, wherein the first holograms are mounted to the first surface and the second holograms are mounted to the second surface;
a first dielectric cover layer over the first holograms; and
a second dielectric cover layer over the second holograms, wherein the second holograms are configured to provide more optical power to the replicated light at a larger diffraction angle from the first holograms than to the replicated light at a smaller diffraction angle from the first holograms, wherein the first holograms comprise a medium having a first set of holograms configured to diffract light of a first wavelength and a second set of holograms that is superimposed with the first set of holograms in the medium and that is configured to diffract light of a second wavelength.

19. A display comprising:
a projector configured to output light;
a first layer of holograms configured to replicate the light over a plurality of output angles by diffracting the light; and
a second layer of holograms configured to focus, onto a focal point, the light diffracted by the first layer of holograms, the light being Bragg-matched to the first layer of holograms at input angles from the projector and at the plurality of output angles, the plurality of output angles being oriented towards the second layer of holograms.

20. The display of claim 19 , wherein the projector comprises a display sel

Assignees

• Apple Inc

Inventors

• Hollands Matthew D
• Simmonds Michael D
• Topliss Richard J
• Gregory Thomas M

Classifications

• G02B27/0172 Primary

  characterised by optical features · CPC title

• G02B27/0103

  comprising holographic elements · CPC title

• G02B2027/013

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

• G02B2027/0105

  Holograms with particular structures · CPC title

• G02B2027/0123

  comprising devices increasing the field of view · CPC title