Optical waveguide devices, methods and systems incorporating same

• US 10,488,666 B2
• Filed: 02/10/2018
• Issued: 11/26/2019
• Est. Priority Date: 02/10/2018
• Status: Active Grant

• Current Assignee: META Platforms Technologies LLC (Meta Platforms, Inc. (f/k/a Facebook, Inc.))
• Original Assignee: DAQRI, LLC
• Inventors: Leighton, James, Pennell, Brennon, Stannard, Adrian, Noui, Louahab, Ma, Nan, Wellington, Iain, Greenhalgh, Philip, Hoar, Lawrence, Wright, Iain
• Primary Examiner(s): Rakowski, Cara E
• Assistant Examiner(s): Lamb, II, Christopher A
• Application Number:
  US15/893,599
• Publication Number:
  US 20190250405A1
• Time in Patent Office: 654 Days
• CPC Class Codes: G02B 2027/0125 Field-of-view increase by wavefront division
• CPC Class Codes: G02B 2027/0178 Eyeglass type eyeglass details G02C
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 6/0035 provided on the surface of the light guide or in the bulk of it

Abstract

An optical device includes a range of angularly selective reflectors are contained within an optical waveguide substrate and substantially optimized according to their reflector order within the sequence of reflectors. This configuration of reflectors ensures that the required angular information is passed through to the correct reflector within the sequence. The angular response in addition reduces or eliminates formation of secondary images carried to successive reflectors, resulting in undesired artefacts.

Claims

1. An optical device comprising

an optical waveguide substrate;

and

a plurality of reflectors spatially distributed in a reflector sequence along a propagation axis of said optical waveguide substrate;

wherein said plurality of reflectors comprises a plurality of angular selective notch filter optical reflectors;

wherein each angular selective notch filter optical reflector is configured both to partially reflect and partially transmit light rays having angles of incidence with respect to the reflector which are in a specific transflectance band of angles selected for each particular reflector and to pass or transmit light rays that have angles of incidence above and below the selected specific transflectance band without reflection, or with reduced reflection compared to light rays having angles of incidence within the selected specific transflectance band;

wherein the specific transflectance band of each angular selective notch filter optical reflector is selected according to the order of the reflector within the sequence of said reflectors in said optical waveguide substrate;

wherein each one of said specific transflectance bands of the plurality of angular selective notch filter optical reflectors is positioned within a range of angles of incidence with respect to the reflectors; and

wherein said plurality of angular selective notch filter optical reflectors are further configured to provide the optical device with a net optical intensity response over said range of angles of incidence with respect to the reflectors which is substantially uniform at different positions across an eye-box plane;

wherein the specific transflectance band of each angular selective notch filter optical reflector is selected to pass desired angular optical image information to the successive reflectors in the sequence according to requirements of an imaging application; and

wherein portions of the specific transflectance bands of the plurality of angular selective notch filter optical reflectors all overlap one another at a same angular position in the range of angles of incidence with respect to the reflectors.

2. The optical device of claim 1, wherein said plurality of angular selective notch filter optical reflectors are disposed in spaced apart parallel planes which are inclined relative to the propagation axis of the optical wave guide substrate.

3. The optical device of claim 2, wherein the angular selective notch-filter optical reflector is configured to have a similar angular response for light rays incident on a front and back, respectively, of the angular selective notch-filter optical reflector.

4. The optical device of claim 1, wherein at least one of said plurality of angular selective notch-filter optical reflectors is a multi-layer dielectric coating or thin film.

5. The optical device of claim 1, wherein the maximum reflectance of respective selected specific transflectance bands of at least some of the angular selective notch-filter optical reflectors progressively decreases according to the reflector order in the reflector sequence.

6. The optical device of claim 1, wherein the angular position of respective selected specific transflectance bands of at least some of the angular selective notch-filter optical reflectors are different from one another.

7. The optical device of claim 6, wherein the angular position of respective selected specific transflectance bands of at least some of the angular selective notch-filter optical reflectors progressively decrease according to the reflector order in the reflector sequence.

8. The optical device of claim 1, wherein the angular range of respective selected specific transflectance bands of at least some of the angular selective notch-filter optical reflectors are different from one another.

9. An optical system comprising:

an augmented reality display optical combiner comprising an optical waveguide substrate and a plurality of reflectors spatially distributed in a reflector sequence along a propagation axis of said optical waveguide substrate;

wherein said plurality of reflectors comprises a plurality of angular selective notch filter optical reflectors;

wherein each angular selective notch filter optical reflector is configured both to partially reflect and partially transmit light rays having angles of incidence with respect to the reflector which are in a specific transflectance band of angles selected for each particular reflector and to pass or transmit light rays that have angles of incidence above and below the selected specific transflectance band without reflection, or with reduced reflection compared to light rays having angles of incidence within the selected specific transflectance band;

wherein the specific transflectance band of each angular selective notch filter optical reflector is selected according to the order of the reflector within the sequence of said reflectors in said optical waveguide substrate;

wherein each one of said specific transflectance bands of the plurality of angular selective notch filter optical reflectors is positioned within a range of angles of incidence with respect to the reflectors;

wherein said plurality of angular selective notch filter optical reflectors are further configured to provide said augmented reality display optical combiner with a net optical response over said range of angles of incidence with respect to the reflectors that is substantially uniform at different positions across an eye-box plane;

wherein the specific transflectance band of each angular selective notch filter optical reflector is selected to substantially optimize primary image angular optical information passing to the successive reflectors in the sequence; and

wherein each one of the specific transflectance bands of the plurality of angular selective notch filter optical reflectors overlaps at least two other specific transflectance bands of the plurality of angular selective notch filter optical reflectors in the range of angles of incidence with respect to the reflectors.

10. The optical system of claim 9, wherein the specific transflectance band of each angular selective notch filter optical reflector is selected to reduce or eliminate secondary images.

11. The optical system of claim 9, wherein said plurality of angular selective notch filter optical reflectors are disposed in spaced apart parallel planes which are inclined relative to the propagation axis of the optical wave guide substrate.

12. The optical system of claim 11, wherein the angular selective notch-filter optical reflector is configured to have a similar angular response to light rays incident on a front and back, respectively, of the angular selective notch-filter optical reflector.

13. The optical system of claim 12, wherein at least one of said plurality of angular selective notch-filter optical reflectors is a multi-layer dielectric coating or thin film.

14. The optical system of claim 13, wherein the maximum reflectance of respective selected specific transflectance bands of at least some of the angular selective notch-filter optical reflectors progressively decrease according to the reflector order in the reflector sequence.

15. The optical system of claim 14 wherein a first one of said angular selective notch filter reflectors in the sequence has a maximum reflectance in the selected specific transflectance band of about 20% and where the last one of said angular selective notch filter reflectors in the sequence has a maximum reflectance in the selected specific transflectance band of about 30%.

16. The optical system of claim 14, wherein the angular position of respective selected specific transflectance bands of at least some of the angular selective notch-filter optical reflectors progressively decrease according to the reflector order in the reflector sequence.

17. The optical system of claim 9, wherein the angular range of respective selected specific transflectance bands of at least some of the angular selective notch-filter optical reflectors are different from one another.

18. The optical system of claim 9, further comprising

a head mounted display;

and

wherein said augmented reality display optical combiner is supported on said head mounted display.