Apple Patent | Head-mounted display systems with gaze tracker alignment monitoring

Patent: Head-mounted display systems with gaze tracker alignment monitoring

Patent PDF: 20240219735

Publication Number: 20240219735

Publication Date: 2024-07-04

Assignee: Apple Inc

Abstract

A head-mounted device may have displays that provide images. Waveguides may be used in conveying the images to eye boxes. The waveguides may overlap lenses in a glasses frame or other head-mounted support structure. The waveguides and lenses may be transparent. This allows real-world objects to be viewed from the eye boxes. Infrared-light reflectors may overlap the lenses. Gaze tracking system light sources may supply infrared light that reflects from the infrared-light reflectors to the eye boxes to illuminate a user's eyes. Gaze tracking system cameras capture gaze tracking images of the eyes from the eye boxes to track the user's gaze. Fiducials associated with the infrared-light reflectors may be monitored using the gaze tracking system cameras. This allows components such as the gaze tracking system cameras to be calibrated.

Claims

What is claimed is:

1. A head-mounted device, comprising:a support structure;a display coupled to the support structure and configured to produce a display image;a waveguide coupled to the support structure and configured to receive the display image;a gaze tracker coupled to the support structure; anda fiducial coupled to the waveguide, wherein the gaze tracker is configured to capture an image of the fiducial.

2. The head-mounted device of claim 1, further comprising:a layer coupled to the waveguide, wherein the layer comprises a grating, and the fiducial is formed from the grating.

3. The head-mounted device of claim 2, wherein the grating is a surface grating on the layer.

4. The head-mounted device of claim 2, wherein the grating is embedded in the layer.

5. The head-mounted device of claim 2, wherein the waveguide has a first edge and an opposing second edge, and the layer extends from the first edge to the second edge.

6. The head-mounted device of claim 1, further comprising:a layer coupled to the waveguide; anda coating on the layer, wherein the coating is patterned to form the fiducial.

7. The head-mounted device of claim 6, wherein the coating comprises metal.

8. The head-mounted device of claim 6, wherein the coating comprises an opaque ink.

9. The head-mounted device of claim 6, wherein the waveguide has a first edge and an opposing second edge, and the layer extends from the first edge to the second edge.

10. The head-mounted device of claim 1, further comprising:a layer coupled to the waveguide, wherein the layer comprises a stack of thin-film dielectric layers, and the fiducial is formed from a pattern in the layer.

11. The head-mounted device of claim 10, wherein the stack of the thin-film dielectric layers forms an infrared reflector.

12. The head-mounted device of claim 10, wherein the waveguide has a first edge and an opposing second edge, and the layer extends from the first edge to the second edge.

13. The head-mounted device of claim 1, wherein the fiducial is formed from a layer that is attached directly to the waveguide.

14. The head-mounted device of claim 1, wherein the fiducial is formed in the waveguide.

15. The head-mounted device of claim 1, further comprising:a lens coupled to the waveguide, wherein the fiducial is formed in the lens.

16. A head-mounted device, comprising:a head-mounted frame;a display in the head-mounted frame and configured to display an image;a waveguide configured to receive the image;a gaze tracking camera configured to gather respective gaze tracking images from an eye box; andfiducials that overlap the waveguide, wherein the gaze tracking camera is configured to capture images of the fiducials.

17. The head-mounted device of claim 16, wherein the fiducials are formed from a layer that is coupled to the waveguide.

18. The head-mounted device of claim 16, further comprising:a lens that overlaps the waveguide, wherein the fiducials are coupled to the lens.

19. The head-mounted device of claim 18, wherein the lens is a removable lens configured to be attached to the waveguide.

20. A head-mounted device, comprising:a head-mounted support structure;a display system coupled to the head-mounted support structure and configured to produce a display image that is directed towards an eye box, wherein the display system comprises a waveguide and a fiducial formed from a coating on the waveguide; anda gaze tracking system having a gaze tracking camera configured to capture an infrared gaze tracking image from the eye box while capturing an image of the fiducial.

Description

This application is a continuation of U.S. patent application Ser. No. 17/988,940, filed Nov. 17, 2022, which is a continuation of U.S. patent application Ser. No. 17/365,815, filed Jul. 1, 2021, now U.S. Pat. No. 11,520,152, which claims the benefit of provisional patent application No. 63/062,347, filed Aug. 6, 2020, which are hereby incorporated by reference herein in their entireties.

FIELD

This relates generally to electronic devices, and, more particularly, to electronic devices such as head-mounted devices.

BACKGROUND

Electronic devices such as head-mounted devices may have displays for displaying images. The displays may be housed in a head-mounted support structure.

SUMMARY

A head-mounted device such as a pair of glasses may have displays for displaying computer-generated content. Waveguides may supply the computer-generated content to a user for viewing while allowing the user to view the real world. Gaze tracking systems may monitor the user's gaze.

The displays of the head-mounted device may supply left and right images to left and right eye boxes. Left and right waveguides may be used in conveying the left and right images to the left and right eye boxes. The left and right waveguides may be transparent. This allows real-world images to be viewed through the left waveguide from the left eye box and through the right waveguide from the right eye box.

Left and right infrared-light reflectors may overlap the left and right waveguides in front of the left and right eye boxes. Left and right gaze tracking system light sources may supply left and right infrared light that reflects respectively from the left and right infrared-light reflectors to the left and right eye boxes. Left and right gaze tracking system cameras may capture left and right gaze tracking images that reflect from the left and right infrared-light reflectors from the left and right eye boxes, respectively.

Fiducials associated with the left and right infrared-light reflectors may be monitored using the left and right gaze tracking system cameras so that the cameras can be calibrated. The fiducials may be formed from patterned portions of the infrared-light reflectors or other fiducial structures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an illustrative electronic device such as a head-mounted display device in accordance with an embodiment.

FIG. 2 is a top view of an illustrative head-mounted device in accordance with an embodiment.

FIG. 3 is a front view of a portion of an illustrative head-mounted device in accordance with an embodiment.

FIG. 4 is a top view of a portion of an illustrative head-mounted device with a gaze tracking system in accordance with an embodiment.

FIG. 5 is a rear view of a portion of an illustrative head-mounted device with gaze tracker calibration fiducials in accordance with an embodiment.

FIG. 6 is a flow chart of illustrative operations involved in calibrating a gaze tracking system in accordance with an embodiment.

FIGS. 7, 8, and 9 are cross-sectional side views of illustrative structures that may be used in forming fiducials in accordance with an embodiment.

FIG. 10 is a cross-sectional side view of a portion of a head-mounted device showing illustrative fiducial locations in accordance with embodiments.

FIG. 11 is a cross-sectional side view of a portion of a head-mounted device with a vision correcting lens in accordance with an embodiment.

FIG. 12 is a front view of an illustrative head-mounted device with fiducials located outside of an eye box reflection area in accordance with an embodiment.

FIG. 13 is a cross-sectional side view of an illustrative gaze tracking camera in accordance with an embodiment.

FIG. 14 is a top view of an illustrative head-mounted device with line-of-sight gaze trackers in accordance with an embodiment.

FIG. 15 is a top cross-sectional view of an illustrative head-mounted device and an associated case with structures to facilitate in-case calibration in accordance with an embodiment.