Waveguide display with spatially switchable grating

• US 10,591,989 B2
• Filed: 12/07/2018
• Issued: 03/17/2020
• Est. Priority Date: 04/03/2017
• Status: Active Grant

• Current Assignee: META Platforms Technologies LLC (Meta Platforms, Inc. (f/k/a Facebook, Inc.))
• Original Assignee: Facebook Technologies, LLC (Meta Platforms, Inc. (f/k/a Facebook, Inc.))
• Inventors: Sulai, Yusufu Njoni Bamaxam, Lam, Wai Sze Tiffany, Lu, Lu
• Primary Examiner(s): Pardo, Thuy N
• Application Number:
  US16/213,854
• Publication Number:
  US 20190171285A1
• Time in Patent Office: 466 Days
• Field of Search: 345 8, 345207, 345428, 345211
• CPC Class Codes: G02B 2027/0138 comprising image capture systems, e.g. camera
• CPC Class Codes: G02B 2027/0178 Eyeglass type eyeglass details G02C
• 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 27/0093 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: G02F 1/011 in optical waveguides, not otherwise provided for in this subclass
• CPC Class Codes: G06F 3/013 Eye tracking input arrangements G06F3/015 takes precedence
• CPC Class Codes: G06F 3/0346 with detection of the device orientation or free movement in a 3D space, e.g. 3D mice, 6-DOF [six degrees of freedom] pointers using gyroscopes, accelerometers or tilt-sensors

Abstract

A near-eye-display (NED) includes an eye tracking system and a waveguide display. The eye tracking system tracks locations based on a location of the user'"'"'s eyes. The waveguide display includes a light source, an output waveguide and a controller. The output waveguide includes a dynamic output grating that outputs an expanded image light to the tracked eyebox locations. The decoupling grating is a 2D array of spatially switchable liquid crystal (LC) pixels including an active subset of LC pixels emitting light only to regions within the tracked eyebox locations. The decoupling grating dynamically out-couples the expanded image light to the tracked location based on switching instructions generated and provided by the controller.

Claims

1. A near-eye-display (NED) system comprising:

an eye tracking system configured to track a location of an eye of a user of the NED;

a light source configured to emit an image light;

an output waveguide to receive the image light and to expand the image light in at least one dimension;

a dynamic output grating comprising an active set of liquid crystal (LC) gratings configured to direct the expanded image light from the output waveguide to the location of the eye of the user and having a configuration that is adjustable; and

a controller configured to change a configuration of the active set of LC gratings according to the location of the eye.

2. The NED of claim 1, wherein the dynamic output grating is oriented along a surface of the output waveguide.

3. The NED of claim 1, wherein the dynamic output grating further comprises an inactive set of LC gratings that are configured to block the expanded image light from the output waveguide to the location, and wherein the controller is further configured to change a configuration of the inactive set of LC gratings according to the location of the eye.

4. The NED of claim 1, wherein the configuration of the active set of LC gratings includes a location of the active set of LC gratings, and the controller is further configured to determine the location of the active set of the LC gratings.

5. The NED of claim 3, wherein the configuration of the inactive set of LC gratings includes a location of the inactive set of LC gratings, and the controller is further configured to determine the location of the inactive set of LC gratings.

6. The NED of claim 1, wherein the controller is configured to determine a location of an eyebox based in part on the tracked location of the eye and wherein the eyebox corresponds to a pupil of the eye.

7. The NED of claim 1, wherein the active set of LC gratings includes LC pixels positioned in a two-dimensional array.

8. The NED of claim 7, wherein each LC pixel is coupled to at least one control electrode that sets an activation state of the LC pixel.

9. The NED of claim 7, wherein the active set of LC grating is a linear waveplate with a periodically varying LC director.

10. The NED of claim 1, wherein the controller is further configured to predict a future location of the eye and to change the configuration of the active set of LC gratings based on the prediction.

11. A waveguide assembly comprising:

an output waveguide to receive an image light emitted from a light source and to expand the image light in at least one dimension;

a dynamic output grating comprising an active set of liquid crystal (LC) gratings configured to direct the expanded image light from the output waveguide to a location of an eyebox and having a configuration that is adjustable; and

a controller configured to change a configuration of the active set of LC gratings according to the location of the eyebox.

12. The waveguide assembly of claim 11, wherein the dynamic output grating is oriented along a surface of the output waveguide.

13. The waveguide assembly of claim 11, wherein the dynamic output grating further comprises an inactive set of LC gratings that are configured to block the expanded image light from the output waveguide to the location, and wherein the controller is further configured to change a configuration of the inactive set of LC gratings according to the location.

14. The waveguide assembly of claim 11, wherein the configuration of the active set of LC gratings includes a location of the active set of LC gratings, and the controller is further configured to determine the location of the active set of the LC gratings.

15. The waveguide assembly of claim 13, wherein the configuration of the inactive set of LC gratings includes a location of the inactive set of LC gratings, and the controller is further configured to determine the location of the inactive set of LC gratings.

16. The waveguide assembly of claim 11, wherein the eyebox corresponds to a pupil of the eye and the controller is configured to determine the location of the eyebox based in part on a location of an eye.

17. The waveguide assembly of claim 11, wherein the active set of LC gratings includes LC pixels positioned in a two-dimensional array.

18. The waveguide assembly of claim 17, wherein each LC pixel is coupled to at least one control electrode that sets an activation state of the LC pixel.

19. The waveguide assembly of claim 17, wherein the active set of LC grating is a linear waveplate with a periodically varying LC director.

20. The waveguide assembly of claim 11, wherein the eyebox corresponds to a pupil of the eye, and wherein the controller is further configured to predict a future location of an eye and to change the configuration of the active set of LC gratings based on the prediction.