Array-based floating display

• US 10,684,470 B2
• Filed: 11/17/2016
• Issued: 06/16/2020
• Est. Priority Date: 03/08/2016
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Inventors: Powell, Karlton D.
• Primary Examiner(s): Beatty, Collin X
• Application Number:
  US15/354,264
• Publication Number:
  US 20170261729A1
• Time in Patent Office: 1,307 Days
• Field of Search: 359662
• CPC Class Codes: G02B 13/26 for reproducing with unit magnification
• CPC Class Codes: G02B 17/002 Arrays of reflective systems
• CPC Class Codes: G02B 17/08 Catadioptric systems used in non-imaging applications G02B19/00
• CPC Class Codes: G02B 17/0856 comprising a refractive element with a reflective surface, the reflection taking place inside the element, e.g. Mangin mirrors
• CPC Class Codes: G02B 2027/0118 comprising devices for improving the contrast of the display / brillance control visibility
• CPC Class Codes: G02B 2027/0145 creating an intermediate image
• CPC Class Codes: G02B 27/01 Head-up displays
• CPC Class Codes: G02B 27/0101 characterised by optical features G02B27/0172 takes precedence
• CPC Class Codes: G02B 27/1066 for enhancing image performance, like resolution, pixel numbers, dual magnifications or dynamic range, by tiling, slicing or overlapping fields of view
• CPC Class Codes: G02B 27/283 used for beam splitting or combining
• CPC Class Codes: G02B 3/0062 Stacked lens arrays, i.e. refractive surfaces arranged in at least two planes, without structurally separate optical elements in-between
• CPC Class Codes: G02B 3/0087 with index gradient
• CPC Class Codes: G02B 30/56 by projecting aerial or floating images
• CPC Class Codes: G02B 5/13 plural curved refracting elements forming part of a unitary body

Abstract

A lens system includes a first lens array assembly including a first plurality of cells, each cell of the first plurality of cells configured to exhibit a pair of first Fourier transform lenses, and a second lens array assembly including a second plurality of cells, each cell of the second plurality of cells configured to exhibit a pair of second Fourier transform lenses. The first and second lens array assemblies are positioned relative to one another along an optical axis of the lens system such that light diverging from an object at a plane disposed at an object conjugate distance from the first lens array assembly reconverges at an image plane after passing through the first and second lens array assemblies. The image plane is disposed at an image conjugate distance from the second lens array assembly in accordance with the object conjugate distance.

Claims

1. A lens system comprising:

a first lens array assembly comprising a first plurality of cells, wherein the first plurality of cells defines a first plane, each cell of the first plurality of cells configured to exhibit a pair of first Fourier transform lenses positioned in normal direction to the first plane, wherein the pair of first Fourier transform lenses of the first lens array are separated in the first plane by a focal length of the first Fourier transform lenses to perform a phase correction; and

a second lens array assembly comprising a second plurality of cells, wherein the second plurality of cells defines a second plane, each cell of the second plurality of cells configured to exhibit a pair of second Fourier transform lenses positioned in normal direction to the second plane, wherein the pair of second Fourier transform lenses of the second lens array are separated in the second plane by a focal length of the second Fourier transform lenses to perform a phase correction;

wherein;

the first and second lens array assemblies are positioned relative to one another along an optical axis of the lens system such that light diverging from an object at a plane disposed at an object conjugate distance from the first lens array assembly reconverges at an image plane after passing through the first and second lens array assemblies; and

the image plane is disposed at an image conjugate distance from the second lens array assembly in accordance with the object conjugate distance.

2. The lens system of claim 1, wherein:

the image conjugate distance is established via a function of the object conjugate distance, a distance between the first and second lens array assemblies, a first focal length of the first plurality of cells, a second focal length of the second plurality of cells, a first pitch of the first plurality of cells, and a second pitch of the second plurality of cells; and

the function establishes that the light diverging from the object reconverges at the image conjugate distance.

3. The lens system of claim 1, wherein the first and second lens array assemblies are spaced apart from one another by a gap of optical media.

4. The lens system of claim 1, wherein the image plane is a floating image plane.

5. The lens system of claim 1, wherein the image conjugate distance substantially equals the object conjugate distance.

6. The lens system of claim 1, wherein the plane of the object and the image plane are oriented in parallel.

7. The lens system of claim 6, wherein the plane of the object and the image plane are oriented orthogonally to the optical axis of the lens system.

8. The lens system of claim 6, wherein the plane of the object and the image plane are oriented orthogonally to a line oriented at an angle to the optical axis of the lens system.

9. The lens system of claim 1, wherein the pairs of first and second Fourier transform lenses have a common focal length.

10. The lens system of claim 1, further comprising a display disposed at the object conjugate distance.

11. The lens system of claim 1, wherein:

further object content is disposed at a second object conjugate distance shorter than the object conjugate distance of the plane; and

the first and second lens array assemblies are configured such that an image of the further object content reconverges at a further image plane that appears to be disposed in a background of the image plane.

12. The lens system of claim 1, wherein:

the first lens array assembly comprises a first pair of in-tandem microlens arrays, each microlens array of the first pair comprising a respective set of constituent lenslets such that each cell of the first plurality of cells comprises a respective one of the constituent lenslets from each respective set of constituent lenslets, each constituent lenslet having a first common focal length;

the second lens array assembly comprises a second pair of in-tandem microlens arrays, each microlens array of the second pair comprising a respective set of constituent lenslets such that each cell of the second plurality of cells comprises a respective one of the constituent lenslets from each respective set of constituent lenslets, each constituent lenslet having a second common focal length;

the in-tandem microlens arrays of the first pair are separated from one another along the optical axis of the lens system by the first common focal length;

the in-tandem microlens arrays of the second pair are separated from one another along the optical axis of the lens system by the second common focal length; and

the first and second pairs of in-tandem microlens arrays are positioned relative to one another along the optical axis such that the image is provided at the image conjugate distance.

13. The lens system of claim 12, wherein the first and second common focal lengths are equal to one another.

14. The lens system of claim 1, wherein:

the first lens array assembly comprises a first array of graded-index microlensing structures;

each graded-index microlensing structure of the first array corresponds with a respective one of the first plurality of cells;

the second lens array assembly comprises a second array of graded-index microlensing structures; and

each graded-index microlensing structure of the second array corresponds with a respective one of the second plurality of cells.

15. A lens system comprising:

a lens array assembly comprising a plurality of cells, wherein the plurality of cells defines a plane, each cell of the plurality of cells configured to exhibit a pair of Fourier transform lenses positioned in normal direction to the plane, wherein the pair of Fourier transform lenses of the lens array are separated in the plane by a focal length of the Fourier transform lenses to perform a phase correction, the lens array assembly disposed along an optical axis to receive light diverging from an object at a plane disposed at an object conjugate distance from the lens array assembly; and

a reflective surface disposed along the optical axis for reflection of the light back through the lens array assembly after reflection off of the reflective surface;

wherein;

the lens array assembly is configured such that the light reconverges at an image plane after passing back through the lens array assembly; and

the image plane is disposed at an image conjugate distance from the lens array assembly in accordance with the object conjugate distance.

16. The lens system of claim 15, further comprising a reflective layer that provides the reflective surface, the reflective layer spaced from the lens array assembly along the optical axis.

17. The lens system of claim 15, wherein the lens array assembly comprises a pair of in-tandem microlens arrays, each microlens array of the pair comprising a respective set of constituent lenslets such that each cell of the plurality of cells comprises a respective one of the constituent lenslets from each respective set of constituent lenslets.

18. The lens system of claim 17, wherein:

the pair of in-tandem microlens arrays comprises a first microlens array and a second microlens array;

the reflective surface is disposed on the second microlens array; and

a focal length of the constituent lenslets of the second microlens array is equal to half of a focal length of the constituent lenslets of the first microlens array to compensate for a change in optical power from the reflective surface.

19. The lens system of claim 17, wherein the respective sets of constituent lenslets have offset pitches.

20. The lens system of claim 15, wherein the plane of the object is oriented at an angle relative to the lens array assembly such that the light passes through a different cell of the plurality of cells after the reflection.

21. The lens system of claim 15, further comprising a display disposed at the object conjugate distance, wherein the image plane is a floating image plane of object content provided by the display.

22. The lens system of claim 15, further comprising a splitter disposed along the optical axis between the plane and the lens array assembly to redirect the light passing back through the lens array assembly.

23. The lens system of claim 22, wherein:

the splitter comprises a polarization splitter; and

the lens assembly comprises an integrated retarder layer.

24. A lens system comprising:

a pair of in-tandem microlens arrays, wherein the microlens arrays define a plane, each microlens array of the pair comprising a respective set of lenslets, each lenslet having a common focal length, wherein the lenslets of the in-tandem microlens arrays are separated in the plane of the microlens arrays by the focal length of the lenslets to perform a phase correction, the pair of in-tandem microlens arrays disposed along an optical axis to receive light diverging from an object; and

a reflective surface disposed along the optical axis for redirection of the light back through the pair of in-tandem microlens arrays after reflection off of the reflective surface;

wherein;

the in-tandem microlens arrays of the pair are spaced from one another along the optical axis by a distance offset from the common focal length such that the light passing back through the pair of in-tandem microlens arrays re-converges with angular spread.

25. The lens system of claim 24, wherein the reflective surface is disposed on one of the pair of in-tandem microlens arrays.

26. The lens system of claim 24, further comprising a substrate having opposing sides on which the microlens arrays of the pair are respectively disposed, the substrate having a thickness that establishes a spacing of the in-tandem microlens arrays of the pair.