Embedded eye tracker with dichroic mirror

• US 10,521,658 B2
• Filed: 07/07/2017
• Issued: 12/31/2019
• Est. Priority Date: 07/07/2017
• 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: Trail, Nicholas Daniel
• Primary Examiner(s): Sheleheda, James R
• Application Number:
  US15/644,203
• Publication Number:
  US 20190012540A1
• Time in Patent Office: 907 Days
• 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: G02B 27/141 using dichroic mirrors
• CPC Class Codes: G02B 27/30 Collimators
• CPC Class Codes: G02B 6/0081 Mechanical or electrical aspects of the light guide and light source in the lighting device peculiar to the adaptation to planar light guides, e.g. concerning packaging
• CPC Class Codes: G02B 6/34 utilising prism or grating G02B6/293 takes precedence
• CPC Class Codes: G06V 10/143 Sensing or illuminating at different wavelengths
• CPC Class Codes: G06V 20/20 in augmented reality scenes
• CPC Class Codes: G06V 40/19 Sensors therefor
• CPC Class Codes: H04N 23/11 for generating image signals from visible and infrared light wavelengths

Abstract

An eyewear device has an optical element, a source, a dichroic mirror, and a camera. The optical element has a front surface, a back surface, a rim, and an angled portion of the rim. The source emits light in a first band of light and is configured to illuminate a portion of an eye of a user of the eyewear device. The dichroic mirror is arranged proximate to the angled portion of the rim, is reflective in the first band of light, is transmissive in a second band of light, and is configured to direct light in the first band reflected from the portion of the eye toward a first position. The camera is located in the first position that is located in a plane of the optical element, and the camera is configured to capture images of the light in the first band reflected by the dichroic mirror.

Claims

1. An eyewear device comprising:

an optical element having a front surface, a back surface, a rim along an outer edge of the optical element, and an angled portion of the rim that is angled relative to the front surface and the back surface;

one or more sources that emit light in a first band of light, the one or more sources configured to illuminate a portion of an eye of a user of the eyewear device;

a dichroic mirror that is arranged parallel to the angled portion of the rim and abuts the angled portion of the rim, the dichroic mirror positioned off-axis from an axis that passes through the optical element to the eye, and the dichroic mirror is reflective in the first band of light, is transmissive in a second band of light, and is configured to direct light in the first band that is reflected from the portion of the eye toward a first position; and

a camera located in the first position and the first position is located in a plane of the optical element, the camera configured to capture one or more images of the light in the first band reflected by the dichroic mirror.

2. The eyewear device of claim 1, further comprising:

a collimator positioned between the dichroic mirror and the camera, the collimator configured to collimate the light in the first band reflected by the dichroic mirror and direct the collimated light toward the camera.

3. The eyewear device of claim 1, wherein the first band of light comprises frequencies of light in an infrared band, and the second band of light comprises frequencies of light in a visible band.

4. The eyewear device of claim 1, wherein the optical element comprises at least one of:

a waveguide display;

a corrective lens; and

a lens configured to filter ultraviolet light.

5. The eyewear device of claim 4, wherein the waveguide display includes a single waveguide.

6. The eyewear device of claim 4, wherein the waveguide display is polychromatic and includes a stacked array of monochromatic waveguides that are each associated with a different band of light.

7. The eyewear device of claim 1, further comprising a controller configured to:

receive the one or more captured images; and

analyze the one or more captured images to determine eye tracking information of the user of the eyewear device.

8. The eyewear device of claim 1, wherein a first angle is formed between the angled portion of the rim and the back surface, and a second angle, smaller than the first angle, is formed between the angled portion of the rim and the front surface.

9. The eyewear device of claim 1, wherein the dichroic mirror is a concave mirror.

10. The eyewear device of claim 1, wherein the camera is positioned such that the camera is out of a line of sight of the user.

11. An eyewear device comprising:

a frame;

a waveguide display inset into the frame and configured to present content to a user of the eyewear device, the waveguide display having a front surface, a back surface, a rim along an outer edge of the optical element, and an angled portion of the rim that is angled relative to the front surface and the back surface;

one or more sources that emit light in a first band of light, the one or more sources configured to illuminate a portion of an eye of the user of the eyewear device;

a dichroic mirror that is arranged parallel to the angled portion of the rim and abuts the angled portion of the rim, the dichroic mirror positioned off-axis from an axis that passes through the optical element to the eye, and the dichroic mirror is reflective in the first band of light, is transmissive in a second band of light, and is configured to direct light in the first band that is reflected from the portion of the eye toward a first position;

a camera located in the first position and the first position is located in a plane of the optical element, the camera configured to capture one or more images of the light in the first band reflected by the dichroic mirror.

12. The eyewear device of claim 11, further comprising:

a collimator positioned between the dichroic mirror and the camera, the collimator configured to collimate the light in the first band reflected by the dichroic mirror and direct the collimated light toward the camera.

13. The eyewear device of claim 11, wherein the first band of light comprises frequencies of light in an infrared band, and the second band of light comprises frequencies of light in a visible band.

14. The eyewear device of claim 11, wherein the waveguide display is monochromatic and includes a single waveguide.

15. The eyewear device of claim 11, wherein the waveguide display is polychromatic and includes a stacked array of monochromatic waveguides that are each associated with a different band of light.

16. The eyewear device of claim 11, further comprising a controller configured to:

receive the one or more captured images; and

analyze the one or more captured images to determine eye tracking information of the user of the eyewear device.

17. An eyewear device comprising:

an optical element having a front surface, a back surface, a rim along an outer edge of the optical element, and an angled portion of the rim that is angled relative to the front surface and the back surface;

a dichroic mirror that is arranged parallel to the angled portion of the rim and abuts the angled portion of the rim, the dichroic mirror positioned off-axis from an axis that passes through the optical element to the eye, and the dichroic mirror is reflective in a first band of light, is transmissive in a second band of light, and is configured to direct light in the first band that is reflected from a portion of an eye of a user of the eyewear device toward a first position; and

a camera located in the first position and the first position is located in a plane of the optical element, the camera configured to capture one or more images of light in the first band reflected by the dichroic mirror.

18. The eyewear device of claim 17, wherein the light in the first band that is reflected from the portion of the eye is emitted by a light source that is external to the eyewear device.

19. The eyewear device of claim 17, wherein the dichroic mirror is a concave mirror.

20. The eyewear device of claim 17, further comprising a controller configured to:

receive the one or more captured images; and

analyze the one or more captured images to determine eye tracking information of the user of the eyewear device.