Meta-optics-based systems and methods for ocular applications
Meta-lens based ocular imaging, near-eye display, and eye-tracking systems are described. The systems can include a single focusing optic and an integrated circuit that provides illumination light and includes an imaging array. The focusing optic includes meta-atoms formed on a substrate. The systems may have no moving parts and achieve imaging or image-projection fields-of-view approaching or exceeding 180 degrees. Because of their low part count, the systems can be robust and have a very small form factor.
1. An ocular imaging system comprising:
a substrate having a first meta-surface formed thereon, the meta-surface comprising an imaging zone having a first plurality of meta-atoms, wherein the meta-surface is to be positioned within 100 mm of an eye's pupil to image an interior portion of the eye;
a light source to illuminate an interior of the eye; and
an array of photodetectors located at a focal surface of the meta-surface to detect an image of the interior portion of the eye that is formed by the imaging zone.
2. The ocular imaging system of claim 1 , wherein the pupil of the eye acts as an aperture stop for the ocular imaging system to obtain high-resolution images.
3. The ocular imaging system of claim 1 , further comprising an illumination zone on the substrate formed from a second plurality of meta-atoms, the second plurality of meta-atoms arranged to collimate, focus, or pattern light from the light source onto the eye.
4. The ocular imaging system of claim 1 , wherein the light source comprises one or more light-emitting diodes adjacent to the array of photodetectors.
5. The ocular imaging system of claim 4 , wherein a total thickness of the ocular imaging system is no greater than 20 mm.
6. The ocular imaging system of claim 4 , wherein a total volume of the ocular imaging system is no greater than 100 cm 3 .
7. The ocular imaging system of claim 1 , wherein the substrate comprises sapphire, silica, calcium fluoride, or a polymer.
8. The ocular imaging system of claim 7 , wherein the first plurality of meta-atoms are formed from a dielectric, semiconductor, or metal material.
9. The ocular imaging system of claim 1 , wherein the first plurality of meta-atoms comprises meta-atoms of at least two different shapes or sizes that are repeated across the substrate.
10. The ocular imaging system of claim 1 , wherein the substrate has at least one curved surface.
11. The ocular imaging system of claim 10 , wherein the focal surface is curved.
12. The ocular imaging system of claim 1 , further comprising:
an aperture stop formed on a second surface of the substrate; and
a relay optic to relay an image of the pupil of the eye onto an aperture formed by the aperture stop.
13. A method of operating an ocular imaging system, the method comprising:
directing light from a light source toward an eye;
collimating, focusing, or patterning the light with an illumination zone of a meta-surface, the illumination zone comprising a first plurality of meta-atoms formed on a substrate;
focusing light reflected from the eye with an imaging zone of the meta-surface, the imaging zone comprising a second plurality of meta-atoms formed on the substrate; and
detecting the focused light with an array of photodetectors.
14. The method of claim 13 , further comprising using the pupil of the eye as an aperture stop for the ocular imaging system.
15. The method of claim 13 , further comprising forming an image of a retina of the eye having a field-of-view that is between 70 degrees and 200 degrees as measured around the interior of the eye.
16. A near-eye display system comprising:
a substrate having a meta-surface formed thereon, the meta-surface comprising a plurality of meta-atoms, wherein the meta-surface is to be positioned within 100 mm of an eye's pupil; and
a micro-emitter array or micro-display located within 10 mm of the meta-surface to form an image that is projected by the meta-surface onto the retina of the eye, wherein the image covers a field-of-view between 70 degrees and 200 degrees as measured around the interior of the eye.
17. The near-eye display system of claim 16 , wherein the near-eye display system utilizes the pupil as an aperture stop to obtain high resolution image projection.
18. The near-eye display system of claim 16 , wherein the substrate is formed of sapphire and the meta-atoms are formed of silicon.
19. An eye-tracking system comprising:
an emitter to produce illumination light;
a first meta-surface that is within 10 mm of the emitter and within 100 mm of an eye, the first meta-surface including a first plurality of meta-atoms formed on a surface of a first substrate and arranged to project a pattern of the illumination light onto the eye;
a second meta-surface located within 100 mm of the eye's pupil, the second meta-surface including a second plurality of meta-atoms arranged to image a region of the eye illuminated by the pattern; and
an imager having a plurality of photodetectors to record an image of the region of the eye.
20. The eye-tracking system of claim 18 , wherein the second meta-surface is formed on a surface of a second substrate that is separated from the first substrate, and wherein the first meta-surface and the second meta-surface lie in a same planar surface or lie in parallel planar surfaces.
21. The eye-tracking system of claim 18 , wherein the second meta-surface is formed on a surface of a second substrate that is separated from the first substrate, and wherein the first meta-surface and the second meta-surface lie on a curved surface.
22. The eye-tracking system of claim 18 , wherein the second meta-surface is formed on the surface of the first substrate, and wherein the emitter and the imager are located on a same substrate.