In-field illuminator for eye depth sensing

1. A near-eye optical device comprising:

a transparent layer to be placed within 25 mm of an eyebox of a user that wears the near-eye optical device, wherein the transparent layer is configured to be mounted to a frame of a head mounted device;

a lens layer in a field of view (FOV) of the user and having a curvature for focusing light to an eyebox, wherein the lens layer is coupled to the transparent layer; and

an in-field illuminator configured to emit near-infrared light centered around a first wavelength, wherein the in-field illuminator is encapsulated with a transparent material of the transparent layer in the FOV of the user; and

a diffractive optical element (DOE) configured to be illuminated by the near-infrared light emitted by the in-field illuminator, wherein, when the DOE is illuminated by the near-infrared light centered around the first wavelength, the DOE generates a structured light projection that includes dots that expand as the structured light projection propagates farther from the DOE, the structured light projection directed by the DOE to illuminate the eyebox, and wherein the structured light projection propagates through the transparent material of the transparent layer.

2. The near-eye optical device of claim 1 further comprising:

a camera configured to image the eyebox, wherein the camera is positioned to image the structured light projection on an eye.

3. The near-eye optical device of claim 2 further comprising:

an optical combiner in the FOV of the user, wherein the optical combiner is configured to receive a reflection of the structured light projection that is reflected off the eye and redirect the reflection of the structured light projection to the camera, the optical combiner configured to be optically transparent to visible light and redirect the near-infrared light centered around the first wavelength to the camera.

4. The near-eye optical device of claim 3 , wherein the optical combiner includes a hologram.

5. The near-eye optical device of claim 3 , wherein the reflection of the structured light projection that is reflected off the eye propagates through the transparent layer prior to encountering the optical combiner.

6. The near-eye optical device of claim 2 , wherein the camera includes a filter that passes the near-infrared light centered around the first wavelength and rejects other wavelength ranges.

7. The near-eye optical device of claim 1 , wherein the near-infrared light is collimated, and wherein the in-field illuminator is configured to emit the collimated near-infrared light.

8. The near-eye optical device of claim 1 , wherein the in-field illuminator includes at least one of an infrared vertical-cavity surface-emitting laser (VCSEL), laser diode, or superluminescent light emitting diode (SLED) with high spatial coherency.

9. The near-eye optical device of claim 1 , wherein the dots are approximately circular in shape.

10. The near-eye optical device of claim 1 , wherein the DOE is a transmissive DOE.

11. The near-eye optical device of claim 1 , wherein the DOE is a reflective DOE.

12. The near-eye optical device of claim 1 , wherein the DOE includes a hologram.

13. The near-eye optical device of claim 1 , wherein the in-field illuminator has a footprint of less than 200 microns by 200 microns.

14. A device comprising:

a frame;

temple arms for securing the device to a head of a user; and

a near-eye optical element mounted to the frame, wherein the near-eye optical element is in a field of view of the user, the near-eye optical element including:

a lens layer in a field of view (FOV) of a user for focusing light to an eyebox;

a transparent layer including a transparent material;

an in-field illuminator configured to emit near-infrared light; and

a diffractive optical element (DOE) configured to be illuminated by the near-infrared light emitted by the in-field illuminator, wherein the DOE is configured to generate a structured light projection that expands as the structured light projection propagates farther from the DOE, the structured light projection propagating through the transparent material of the transparent layer and propagating through the lens layer to illuminate the eyebox.

15. The device of claim 14 , wherein the near-eye optical element includes an optical combiner configured to receive a reflection of the structured light projection that is reflected off the eye and redirect the reflection of the structured light projection to a camera, the optical combiner configured to be optically transparent to visible light and redirect the near-infrared light centered around the first wavelength to the camera.

16. The device of claim 14 , wherein the DOE is disposed between the in-field illuminator and the lens layer.

17. A head mounted display (HMD) comprising:

a frame; and

a near-eye optical element mounted to the frame, wherein the near-eye optical element is configured to pass scene light from a scene of an external environment to an eyebox, the near-eye optical element including:

a transparent layer including a transparent material;

an in-field illuminator configured to emit near-infrared light; and

a diffractive optical element (DOE) configured to be illuminated by the near-infrared light emitted by the in-field illuminator, wherein the DOE is configured to generate a structured light projection that expands as the structured light projection propagates farther from the DOE, the transparent material of the transparent layer configured to pass the scene light and pass the structured light projection generated by the DOE to illuminate the eyebox.