Advanced femtoprojector optical systems

• US 10,613,334 B2
• Filed: 05/21/2018
• Issued: 04/07/2020
• Est. Priority Date: 05/21/2018
• Status: Active Grant

• Current Assignee: Tectus Corporation
• Original Assignee: Tectus Corporation
• Inventors: Lemoff, Brian Elliot, Mihalakis, George Michael
• Primary Examiner(s): Sarma, Abhishek
• Application Number:
  US15/985,511
• Publication Number:
  US 20190353903A1
• Time in Patent Office: 687 Days
• CPC Class Codes: G02B 17/0615 off-axis or unobscured systems in wich all of the mirrors share a common axis of rotational symmetry
• CPC Class Codes: G02B 2027/013 comprising a combiner of particular shape, e.g. curvature
• CPC Class Codes: G02B 2027/0138 comprising image capture systems, e.g. camera
• CPC Class Codes: G02B 2027/0147 comprising a device modifying the resolution of the displayed image
• 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 2027/0196 having transparent supporting structure for display mounting, e.g. to a window or a windshield
• CPC Class Codes: G02B 27/0018 with means for preventing ghost images anti-reflection coatings G02B1/11
• 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 27/0179 Display position adjusting means not related to the information to be displayed
• CPC Class Codes: G02B 27/20 for imaging minute objects, e.g. light-pointer
• CPC Class Codes: G02C 11/10 Electronic devices other than hearing aids
• CPC Class Codes: G02C 7/04 Contact lenses for the eyes disinfection or sterilisation of contact lenses A61L12/00
• CPC Class Codes: G02C 7/049 Contact lenses having special fitting or structural features achieved by special materials or material structures
• CPC Class Codes: G02C 7/086 Auxiliary lenses located directly on a main spectacle lens or in the immediate vicinity of main spectacles
• CPC Class Codes: G03B 21/2033 LED or laser light sources
• CPC Class Codes: G03B 21/28 Reflectors in projection beam in illumination beam G03B21/2066

Abstract

A variety of femtoprojector optical systems are described. Each of them can be made small enough to fit in a contact lens using plastic injection molding, diamond turning, photolithography and etching, or other techniques. Most of the systems include a solid transparent substrate with a curved primary mirror formed on one face, a secondary mirror formed on the opposite face, and an annular exit aperture located axially between the two mirrors The designs use light blocking, light-redirecting, absorbing coatings or other types of baffle structures to reduce stray light.

Claims

1. A femtoprojector optical system for projecting an image produced by an image source to a retina of a user'"'"'s eye when an eye-mounted display containing the femtoprojector optical system is mounted on the user'"'"'s eye, the femtoprojector optical system comprising:

a convex secondary mirror facing the image source;

a concave primary mirror facing the secondary mirror, the secondary mirror and primary mirror cooperating to project the image from the image source;

a baffle system comprising;

a three-dimensional obscuration extending from the secondary mirror towards the primary mirror, where the obscuration blocks stray rays that are not reflected by the secondary mirror;

an annular exit aperture having an inner edge and an outer edge, the exit aperture positioned at an axial location that is between the convex secondary mirror and the concave primary mirror, where;

image-forming rays from the image source are incident on and reflected by the secondary mirror to the primary mirror and out the exit aperture;

the three-dimensional obscuration is positioned between the secondary mirror and the inner edge of the exit aperture; and

the obscuration blocks stray rays that propagate directly from the image source to between the secondary mirror and the inner edge; and

where the femtoprojector optical system fits within a 2 mm×

2 mm×

2 mm volume.

2. The femtoprojector optical system of claim 1 where the axial location of the exit aperture is closer to midway between the primary and secondary mirrors, than to either the primary mirror or the secondary mirror.

3. The femtoprojector optical system of claim 1 where the obscuration extends an entire length between the secondary mirror and the inner edge of the exit aperture.

4. The femtoprojector optical system of claim 1 where the obscuration comprises:

an annular portion adjacent to the secondary mirror; and

a frustum-shaped portion extending an entire length between the annular portion and the inner edge of the exit aperture.

5. The femtoprojector optical system of claim 1 where the baffle system further comprises:

an external side baffle extending from the outer edge of the exit aperture away from the primary mirror, where the external side baffle blocks stray rays that propagate directly from the image source through the exit aperture.

6. The femtoprojector optical system of claim 5 where the external side baffle blocks all stray rays that propagate directly from the image source through the exit aperture and the external side baffle does not extend beyond the secondary mirror.

7. The femtoprojector optical system of claim 5 where the external side baffle does not extend beyond the secondary mirror.

8. The femtoprojector optical system of claim 5 where the external side baffle is tapered outwards from the outer edge of the exit aperture.

9. The femtoprojector optical system of claim 8 where the external side baffle is tapered at an angle in a range of 2.5 to 10 degrees.

10. The femtoprojector optical system of claim 1 where the baffle system further comprises:

an internal side baffle extending from the outer edge of the exit aperture toward the primary mirror.

11. The femtoprojector optical system of claim 2 further comprising:

a solid transparent substrate with the primary mirror on one face of the solid transparent substrate and with the secondary mirror and the exit aperture on opposing faces of the solid transparent substrate.

12. The femtoprojector optical system of claim 11 where the primary mirror and secondary mirror are implemented as reflective coatings on the substrate, and the obscuration is implemented as an absorptive coating on the substrate.

13. The femtoprojector optical system of claim 1 where the baffle system operates so that no stray rays can propagate directly from the image source to a pupil of the user'"'"'s eye when the eye-mounted display is mounted on the user'"'"'s eye.

14. The femtoprojector optical system of claim 1 where the exit aperture includes a refractive interface between two materials of different indices of refraction.

15. The femtoprojector optical system of claim 1 where the femtoprojector has an F/number of F/17 or slower.

16. The femtoprojector optical system of claim 1 where the femtoprojector optical system is small enough to mount in a contact lens wearable by the user.

17. The femtoprojector optical system of claim 1 where the exit aperture has a maximum lateral dimension of not more than 1 mm.

18. A femtoprojector optical system for projecting an image produced by an image source to a retina of a user'"'"'s eye when an eye-mounted display containing the femtoprojector optical system is mounted on the user'"'"'s eye, the femtoprojector optical system comprising:

a convex secondary mirror facing the image source;

a concave primary mirror facing the secondary mirror; and

an annular exit aperture having an inner edge and an outer edge, the exit aperture positioned at an axial location that is between the convex secondary mirror and the concave primary mirror, where image-forming rays from the image source are incident on and reflected by the secondary mirror to the primary mirror and out the exit aperture, the secondary mirror and primary mirror cooperating to project the image from the image source; and

a baffle system comprising;

a three-dimensional obscuration that extends an entire length between the secondary mirror and the inner edge of the exit aperture, where the obscuration blocks all stray rays that propagate directly from the image source to between the secondary mirror and the inner edge;

an external side baffle extending and tapering outwards from the outer edge of the exit aperture away from the primary mirror, where the external side baffle blocks all stray rays that propagate directly from the image source through the exit aperture; and

an internal side baffle extending from the outer edge of the exit aperture toward the primary mirror; and

a solid transparent substrate, with the primary mirror implemented as a reflective coating on one face of the solid transparent substrate, with the secondary mirror implemented as a reflective coating on an opposing face of the solid transparent substrate, with the exit aperture implemented as a refractive interface on another opposing face of the solid transparent substrate, and with the obscuration and the internal side baffle implemented as absorptive coatings on the solid transparent substrate; and

where the femtoprojector optical system fits within a 2 mm×

2 mm×

2 mm volume.

19. An optical system for projecting an image produced by an image source, the optical system comprising:

a convex secondary mirror facing the image source;

a concave primary mirror facing the secondary mirror;

an annular exit aperture having an inner edge and an outer edge, the exit aperture positioned at an axial location that is between the convex secondary mirror and the concave primary mirror, where image-forming rays from the image source are incident on and reflected by the secondary mirror to the primary mirror and out the exit aperture, the secondary mirror and primary mirror cooperating to project the image from the image source; and

a baffle system comprising;

a three-dimensional obscuration between the secondary mirror and the inner edge of the exit aperture, where the obscuration blocks stray rays that propagate directly from the image source to between the secondary mirror and the inner edge.

20. The optical system of claim 19 where the axial location of the exit aperture is closer to midway between the primary and secondary mirrors, than to either the primary mirror or the secondary mirror.

21. The optical system of claim 19 where the obscuration extends an entire length between the secondary mirror and the inner edge of the exit aperture.

22. The optical system of claim 19 where the obscuration comprises:

an annular portion adjacent to the secondary mirror; and

a frustum-shaped portion extending an entire length between the annular portion and the inner edge of the exit aperture.

23. The optical system of claim 19 where the baffle system further comprises:

an external side baffle extending from the outer edge of the exit aperture away from the primary mirror, where the external side baffle blocks stray rays that propagate directly from the image source through the exit aperture.

24. The optical system of claim 23 where the external side baffle blocks all stray rays that propagate directly from the image source through the exit aperture and the external side baffle does not extend beyond the secondary mirror.

25. The optical system of claim 23 where the external side baffle does not extend beyond the secondary mirror.

26. The optical system of claim 23 where the external side baffle is tapered outwards from the outer edge of the exit aperture.

27. The optical system of claim 26 where the external side baffle is tapered at an angle in a range of 2.5 to 10 degrees.

28. The optical system of claim 19 where the baffle system further comprises:

an internal side baffle extending from the outer edge of the exit aperture toward the primary mirror.

29. The optical system of claim 19 further comprising:

a solid transparent substrate with the primary mirror on one face of the solid transparent substrate and with the secondary mirror and the exit aperture on opposing faces of the solid transparent substrate.

30. The optical system of claim 29 where the primary mirror and secondary mirror are implemented as reflective coatings on the substrate, and the obscuration is implemented as an absorptive coating on the substrate.

31. The optical system of claim 19 where the exit aperture has a maximum lateral dimension of not more than 1 mm.

32. The optical system of claim 19 where the optical system fits within a 2 mm×

2 mm×

2 mm volume.