SYSTEMS, DEVICES, AND METHODS FOR CURVED HOLOGRAPHIC OPTICAL ELEMENTS

• US 20170212290A1
• Filed: 12/16/2016
• Published: 07/27/2017
• Est. Priority Date: 12/17/2015
• Status: Abandoned Application

• Current Assignee: North Inc.
• Original Assignee: Thalmic Labs Inc.
• Inventors: Morrison, Vance R., Alexander, Stefan, Mahon, Thomas
• Application Number:
  US15/381,883
• Publication Number:
  US 20170212290A1
• Time in Patent Office: Days
• CPC Class Codes: G02B 2027/015 involving arrangement aiming to get less bulky devices
• CPC Class Codes: G02B 2027/0174 holographic
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 5/32 Holograms used as optical elements
• CPC Class Codes: G03H 1/0402 Recording geometries or arrangements G03H1/0443, G03H1/0476, G03H1/16 take precedence
• CPC Class Codes: G03H 1/0465 Particular recording light; Beam shape or geometry G03H1/06 takes precedence
• CPC Class Codes: G03H 1/181 Pre-exposure processing, e.g. hypersensitisation
• CPC Class Codes: G03H 1/182 Post-exposure processing, e.g. latensification
• CPC Class Codes: G03H 1/202 Contact copy when the reconstruction beam for the master H1 also serves as reference beam for the copy H2
• CPC Class Codes: G03H 2001/043 Non planar recording surface, e.g. curved surface
• CPC Class Codes: G03H 2001/0439 for recording Holographic Optical Element [HOE] HOE per se G02B5/32
• CPC Class Codes: G03H 2001/186 Swelling or shrinking the holographic record or compensation thereof, e.g. for controlling the reconstructed wavelength G03H2001/0033, G03H2250/44 take precedence
• CPC Class Codes: G03H 2260/12 Photopolymer
• CPC Class Codes: G03H 2270/21 Curved bearing surface

Abstract

Systems, devices, and methods for making, replicating, and using curved holographic optical elements (“HOEs”) are described. A hologram may be optically recorded into a planar layer of holographic film with various measures in place to compensate for changes (e.g., in optical power and/or playback wavelength and/or angular bandwidth) that may result when a curvature is subsequently applied thereto. A hologram may be optically recorded into a curved layer of holographic film with various measures in place to compensate for optical effects of a curved transparent substrate upon which the holographic film is mounted. A curved HOE may be returned to a planar configuration to undergo holographic replication or holographic replication may be performed using a curved master HOE and curved “recipient” film. The curved HOEs described herein are particularly well-suited for use when integrated with a curved eyeglass lens to form the transparent combiner of a virtual retina display.

Claims

1. A method of producing a curved holographic optical element (“

HOE”

) that comprises at least one hologram recorded in a holographic film, wherein the curved HOE has a total optical power P_T, the method comprising;

positioning and orienting the holographic film in a planar geometry;

optically recording a hologram in the holographic film while the holographic film is in the planar geometry, wherein the hologram has a holographic optical power P_H that is less than the total optical power P_T of the curved HOE; and

applying a curvature to the holographic film, wherein applying the curvature to the holographic film includes applying a geometric optical power P_G to the holographic film, the geometric optical power P_G less than the total optical power P_T of the curved HOE, and wherein the total optical power P_T of the curved HOE includes an additive combination of the holographic optical power P_H and the geometric optical power P_G given, at least approximately, by P_T=P_H+P_G.

2. The method of claim 1 wherein:

positioning and orienting the holographic film in a planar geometry includes mounting the holographic film on a planar surface; and

optically recording a hologram in the holographic film while the holographic film is in the planar geometry includes optically recording the hologram in the holographic film while the holographic film is mounted on the planar surface, and the method further comprising;

removing the holographic film from the planar surface before applying the curvature to the holographic film.

3. The method of claim 1 wherein applying a curvature to the holographic film includes at least one of:

mounting the holographic film on a curved surface or embedding the holographic film within a curved volume.

4. The method of claim 1 wherein optically recording a hologram in the holographic film while the holographic film is in the planar geometry includes optically recording the hologram in the holographic film with a first laser having a first wavelength while the holographic film is in the planar geometry, the first wavelength different from a playback wavelength of the curved HOE.

5. The method of claim 4 wherein applying a curvature to the holographic film includes stretching the holographic film, and wherein optically recording the hologram in the holographic film with a first laser having a first wavelength while the holographic film is in the planar geometry includes optically recording the hologram in the holographic film with the first laser having a first wavelength that is less than the playback wavelength of the curved HOE.

6. The method of claim 4 wherein applying a curvature to the holographic film includes compressing the holographic film, and wherein optically recording the hologram in the holographic film with a first laser having a first wavelength while the holographic film is in the planar geometry includes optically recording the hologram in the holographic film with the first laser having a first wavelength that is greater than the playback wavelength of the curved HOE.

7. The method of claim 1 wherein optically recording a hologram in the holographic film while the holographic film is in the planar geometry includes optically recording the hologram in the holographic film with a first laser at a first incidence angle while the holographic film is in the planar geometry, the first incidence angle different from a playback incidence angle of the curved HOE.

8. The method of claim 1 wherein the total optical power P_T of the curved HOE is positive with a total focal length f_T, and wherein:

optically recording a hologram in the holographic film while the holographic film is positioned and oriented in the planar geometry includes optically recording a hologram having a positive holographic optical power P_H and a first focal length f_H that is greater than the total focal length f_T of the curved HOE; and

applying a curvature to the holographic film includes applying a positive geometric optical power P_G having a second focal length f_G to the holographic film, the second focal length f_G greater than the total focal length f_T of the curved HOE, wherein the total focal length f_T of the curved HOE includes an additive reciprocal combination of the first focal length f_H and the second focal length f_G given, at least approximately, by 1/f_T=1/f_H+1/f_G.

9. A curved holographic optical element (“

HOE”

) having a total optical power P_T, comprising;

at least one curved layer of holographic film that includes at least one hologram, wherein;

the at least one hologram has a holographic optical power P_H that is less than the total optical power P_T of the curved HOE; and

the at least one curved layer of holographic film has a geometric optical power P_G that is less than the total optical power P_T of the curved HOE, and wherein the total optical power P_T of the curved HOE includes an additive combination of the holographic optical power P_H of the at least one hologram and the geometric optical power P_G of the at least one curved layer of holographic film given, at least approximately, by P_T=P_H+P_G.

10. The curved HOE of claim 9 wherein:

the total optical power P_T of the curved HOE is positive and includes a total focal length f_T;

the holographic optical power P_H of the at least one hologram is positive and has a first focal length f_H that is greater than the total focal length f_T of the curved HOE; and

the geometric optical power P_G of the at least one curved layer of holographic film is positive and has a second focal length f_G that is greater than the total focal length f_T of the curved HOE, and wherein the total focal length f_T of the curved HOE includes an additive reciprocal combination of the first focal length f_H and the second focal length f_G given, at least approximately, by 1/f_T=1/f_H+1/f_G.

11. A method of producing a curved holographic optical element (“

HOE”

) that comprises at least one hologram recorded in a holographic film, the method comprising;

positioning and orienting the holographic film in a planar geometry;

optically recording a hologram in the holographic film with a first laser having a first wavelength while the holographic film is in the planar geometry, the first wavelength different from a playback wavelength of the curved HOE; and

applying a curvature to the holographic film.

12. The method of claim 11 wherein applying a curvature to the holographic film includes stretching the holographic film, and wherein optically recording the hologram in the holographic film with a first laser having a first wavelength while the holographic film is in the planar geometry includes optically recording the hologram in the holographic film with the first laser having a first wavelength that is less than the playback wavelength of the curved HOE.

13. The method of claim 11 wherein applying a curvature to the holographic film includes compressing the holographic film, and wherein optically recording the hologram in the holographic film with a first laser having a first wavelength while the holographic film is in the planar geometry includes optically recording the hologram in the holographic film with the first laser having a first wavelength that is greater than the playback wavelength of the curved HOE.

14. The method of claim 11 wherein:

optically recording a hologram in the holographic film while the holographic film is in the planar geometry includes optically recording the hologram with a holographic optical power P_H that is less than a total optical power P_T of the curved HOE while the holographic film is in the planar geometry; and

applying a curvature to the holographic film includes applying a geometric optical power P_G that is less than the total optical power P_T of the curved HOE to the holographic film, and wherein the total optical power P_T of the curved HOE includes an additive combination of the holographic optical power P_H and the geometric optical power P_G given, at least approximately, by P_T=P_H+P_G.

15. The method of claim 11 wherein:

positioning and orienting the holographic film in a planar geometry includes mounting the holographic film on a planar surface; and

optically recording a hologram in the holographic film with a first laser having a first wavelength while the holographic film is in the planar geometry includes optically recording the hologram in the holographic film with the first laser having the first wavelength while the holographic film is mounted on the planar surface, and wherein the method further comprises;

removing the holographic film from the planar surface before applying the curvature to the holographic film.

16. The method of claim 11 wherein applying a curvature to the holographic film includes at least one of:

mounting the holographic film on a curved surface or embedding the holographic film within a curved volume.

17. A method of producing a holographic optical element (“

HOE”

) that comprises at least one hologram recorded in a holographic film, the method comprising;

providing a first layer of holographic film in a planar geometry;

stretching the first layer of holographic film;

optically recording a hologram in the first layer of holographic film while the first layer of holographic film is stretched; and

returning the first layer of holographic film to an unstretched state.

18. The method of claim 17 wherein stretching the first layer of holographic film includes mounting the first layer of holographic film onto a curved surface.

19. The method of claim 17, further comprising at least one of:

mounting the first layer of holographic film on a curved surface for playback;

or

embedding the first layer of holographic film within a curved volume for playback.

20. The method of claim 19 wherein mounting the first layer of holographic film on a curved surface for playback includes stretching the first layer of holographic film in the direction normal to a plane of the first layer of holographic film onto the curved surface.

21. The method of claim 17, further comprising:

providing a second layer of holographic film in a planar geometry;

replicating the hologram from the first layer of holographic film in the second layer of holographic film while both the first layer of holographic film and the second layer of holographic film are each in respective unstretched states; and

at least one of;

mounting the second layer of holographic film on a curved surface for playback or embedding the second layer of holographic film within a curved volume for playback.

22. The method of claim 21 wherein mounting the second layer of holographic film on a curved surface for playback includes stretching the second layer of holographic film in a direction normal to a plane of the second layer of holographic film onto the curved surface.

23. A method of producing a curved holographic optical element (“

HOE”

), the method comprising;

mounting a holographic film on a first surface, the first surface being transparent and having a first curvature; and

optically recording a hologram in the holographic film while the holographic film is mounted on the first surface.

24. The method of claim 23, further comprising:

removing the holographic film from the first surface; and

at least one of;

mounting the holographic film on a second surface for playback, the second surface having a second curvature substantially equal to the first curvature;

or

embedding the holographic film within a curved volume for playback, the curved volume having a second curvature substantially equal to the first curvature.

25. A method of replicating a curved holographic optical element (“

HOE”

) that comprises at least one hologram recorded in a holographic film, the method comprising;

providing a first layer of holographic film;

mounting the first layer of holographic film on a first surface, the first surface having a first curvature;

optically recording a hologram in the first layer of holographic film while the first layer of holographic film is mounted on the first surface;

providing a second layer of holographic film;

applying the first curvature to the second layer of holographic film; and

replicating the hologram from the first layer of holographic film in the second layer of holographic film while both the first layer of holographic film and the second layer of holographic film each have the first curvature.