SYSTEMS, DEVICES, AND METHODS FOR EYEBOX EXPANSION IN WEARABLE HEADS-UP DISPLAYS

• US 20160377865A1
• Filed: 02/17/2016
• Published: 12/29/2016
• Est. Priority Date: 02/17/2015
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Thalmic Labs Inc.
• Inventors: Alexander, Stefan, Bailey, Matthew, Morrison, Vance R., Holland, Lloyd Frederick
• Granted Patent: US 10,031,338 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G02B 2027/0112 comprising device for genereting colour display
• CPC Class Codes: G02B 2027/0123 comprising devices increasing the field of view
• CPC Class Codes: G02B 2027/0125 Field-of-view increase by wavefront division
• CPC Class Codes: G02B 2027/0174 holographic
• CPC Class Codes: G02B 2027/0178 Eyeglass type eyeglass details G02C
• CPC Class Codes: G02B 26/10 Scanning systems
• CPC Class Codes: G02B 27/0081 with means for altering, e.g. enlarging, the entrance or exit pupil
• CPC Class Codes: G02B 27/017 Head mounted
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 27/12 operating by refraction only
• CPC Class Codes: G03H 1/2645 Multiplexing processes, e.g. aperture, shift, or wavefront multiplexing
• CPC Class Codes: G03H 1/265 Angle multiplexing; Multichannel holograms G03H1/268 takes precedence
• CPC Class Codes: G03H 2001/266 Wavelength multiplexing
• CPC Class Codes: G06F 1/163 Wearable computers, e.g. on a belt
• CPC Class Codes: G06F 3/011 Arrangements for interaction with the human body, e.g. for user immersion in virtual reality blind teaching G09B21/00
• CPC Class Codes: G06F 3/013 Eye tracking input arrangements G06F3/015 takes precedence
• CPC Class Codes: G09G 3/001 using specific devices not provided for in groups G09G3/02 - G09G3/36, e.g. using an intermediate record carrier such as a film slide; Projection systems; Display of non-alphanumerical information, solely or in combination with alphanumerical information, e.g. digital display on projected diapositive as background slide projectors per se G03B23/00 = 42 HP

Abstract

Systems, devices, and methods for eyebox expansion by exit pupil replication in scanning laser-based wearable heads-up displays (“WHUDs”) are described. The WHUDs described herein each include a scanning laser projector (“SLP”), a holographic combiner, and an optical replicator positioned in the optical path therebetween. For each light signal generated by the SLP, the optical replicator receives the light signal and redirects each one of N>1 instances of the light signal towards the holographic combiner effectively from a respective one of N spatially-separated virtual positions for the SLP. The holographic combiner converges each one of the N instances of the light signal to a respective one of N spatially-separated exit pupils at the eye of the user. In this way, multiple instances of the exit pupil are distributed over the area of the eye and the eyebox of the WHUD is expanded.

Claims

1. A wearable heads-up display comprising:

a support structure that in use is worn on a head of a user;

a scanning laser projector carried by the support structure;

a holographic combiner carried by the support structure, wherein the holographic combiner is positioned within a field of view of an eye of the user when the support structure is worn on the head of the user; and

an optical replicator carried by the support structure and positioned in an optical path between the scanning laser projector and the holographic combiner, the optical replicator comprising at least one optical element arranged to receive a light signal generated by the scanning laser projector and redirect respective ones of N instances of the light signal towards the holographic combiner, where N is an integer greater than 1, and wherein the holographic combiner comprises at least one hologram positioned and oriented to redirect each one of the N instances of the light signal towards the eye of the user.

2. The wearable heads-up display of claim 1 wherein the at least one hologram of the holographic combiner redirects the N instances of the light signal all spatially in parallel with one another towards respective regions of the eye of the user.

3. The wearable heads-up display of claim 1 wherein at least one optical element of the optical replicator is arranged to redirect respective ones of the N instances of the light signal towards the holographic combiner effectively from respective ones of N spatially-separated virtual positions for the scanning laser projector.

4. The wearable heads-up display of claim 1 wherein the support structure has a general shape and appearance of an eyeglasses frame.

5. The wearable heads-up display of claim 4, further comprising:

a prescription eyeglass lens, wherein the holographic combiner is carried by the prescription eyeglass lens.

6. The wearable heads-up display of claim 1 wherein the at least one hologram of the holographic combiner converges each one of the N instances of the light signal to a respective one of N exit pupils at or proximate the eye of the user.

7. The wearable heads-up display of claim 6 wherein the holographic combiner includes at least N multiplexed holograms, and wherein each one of the at least N multiplexed holograms converges a respective one of the N instances of the light signal to a respective one of the N exit pupils at or proximate the eye of the user.

8. The wearable heads-up display of claim 6 wherein:

the scanning laser projector includes a red laser diode, a green laser diode, and a blue laser diode; and

the holographic combiner includes a wavelength-multiplexed holographic combiner that includes at least one red hologram, at least one green hologram, and at least one blue hologram, and wherein the at least one red hologram converges a respective red component of each one of the N instances of the light signal to a respective one of the N exit pupils at or proximate the eye of the user, the at least one green hologram converges a respective green component of each one of the N instances of the light signal to a respective one of the N exit pupils at or proximate the eye of the user, and the at least one blue hologram converges a respective blue component of each one of the N instances of the light signal to a respective one of the N exit pupils at or proximate the eye of the user.

9. The wearable heads-up display of claim 8 wherein the holographic combiner includes a wavelength-multiplexed and angle-multiplexed holographic combiner that includes at least N angle-multiplexed red holograms, at least N angle-multiplexed green holograms, and at least N angle-multiplexed blue holograms, and wherein each one of the at least N angle-multiplexed red holograms converges a respective red component of each one of the N instances of the light signal to a respective one of the N exit pupils at or proximate the eye of the user, each one of the at least N angle-multiplexed green holograms converges a respective green component of each one of the N instances of the light signal to a respective one of the N exit pupils at or proximate the eye of the user, and each one of the at least N angle-multiplexed blue holograms converges a respective blue component of each one of the N instances of the light signal to a respective one of the N exit pupils at or proximate the eye of the user.

10. The wearable heads-up display of claim 1 wherein the optical path between the scanning laser projector and the holographic combiner includes a total scan range θ

of the scanning laser projector, and wherein at least one optical element of the optical replicator is arranged to receive all light signals corresponding to a sweep of the total scan range θ

by the scanning laser projector and redirect respective ones of N instances of all light signals corresponding to the sweep of the total scan range θ

of the scanning laser projector towards the holographic combiner.

11. The wearable heads-up display of claim 1 wherein the light signal includes an image comprising at least two pixels.

12. The wearable heads-up display of claim 11 wherein each one of the N instances of the light signal includes a respective instance of the image.

13. The wearable heads-up display of claim 1 wherein each one of the N instances of the light signal includes a respective instance of a same pixel in a different instance of a same image.

14. The wearable heads-up display of claim 1, further comprising:

an eye tracker carried by the support structure, positioned and oriented to determine a gaze direction of the eye of the user; and

at least one controllable shutter carried by the support structure and positioned in at least one optical path between the optical replicator and the holographic combiner, the at least one controllable shutter controllable to selectively block all but at least one of the N instances of the light signal redirected towards the holographic combiner by the optical replicator, the at least one of the N instances of the light signal that is not blocked by the at least one controllable shutter corresponding to the at least one of the N instances of the light signal that, when redirected by the holographic combiner, is redirected by the holographic combiner towards a region of the eye of the user that contains a pupil of the eye of the user based on the gaze direction of the eye of the user determined by the eye tracker.

15. A method of operating a wearable heads-up display, the wearable heads-up display including a scanning laser projector, an optical replicator, and a holographic combiner positioned within a field of view of an eye of a user when the wearable heads-up display is worn on a head of the user, the method comprising:

generating a first light signal by the scanning laser projector;

redirecting respective ones of N instances of the first light signal towards the holographic combiner by the optical replicator, where N is an integer greater than 1; and

redirecting each instance of the first light signal that is received from the optical replicator towards the eye of the user by the holographic combiner.

16. The method of claim 15, further comprising:

receiving the first light signal from the scanning laser projector by the optical replicator; and

replicating the first light signal into the N instances of the first light signal by the optical replicator.

17. The method of claim 15 wherein redirecting each instance of the first light signal that is received from the optical replicator towards the eye of the user by the holographic combiner includes redirecting each instance of the first light signal that is received from the optical replicator spatially in parallel with one another towards respective regions of the eye of the user by the holographic combiner.

18. The method of claim 15 wherein redirecting respective ones of N instances of the first light signal towards the holographic combiner by the optical replicator includes redirecting respective ones of N instances of the first light signal towards the holographic combiner by the optical replicator effectively from respective ones of N spatially-separated virtual positions for the scanning laser projector.

19. The method of claim 15 wherein redirecting each instance of the first light signal that is received from the optical replicator towards the eye of the user by the holographic combiner includes converging each instance of the first light signal that is received from the optical replicator to a respective exit pupil at or proximate the eye of the user by the holographic combiner.

20. The method of claim 19 wherein the holographic combiner includes at least two multiplexed holograms, and wherein converging each instance of the first light signal that is received from the optical replicator to a respective exit pupil at or proximate the eye of the user by the holographic combiner includes converging each instance of the first light signal that is received from the optical replicator to a respective exit pupil at or proximate the eye of the user by a respective multiplexed hologram.

21. The method of claim 20 wherein:

the scanning laser projector includes a red laser diode, a green laser diode, and a blue laser diode;

the first light signal generated by the scanning laser projector includes a red component, a green component, and a blue component; and

the holographic combiner includes a wavelength-multiplexed holographic combiner that includes at least one red hologram, at least one green hologram, and at least one blue hologram, and wherein converging each instance of the first light signal that is received from the optical replicator to a respective exit pupil at or proximate the eye of the user by a respective multiplexed hologram includes;

converging a respective red component of each instance of the first light signal that is received from the optical replicator to a respective exit pupil at or proximate the eye of the user by the at least one red hologram;

converging a respective green component of each instance of the first light signal that is received from the optical replicator to a respective exit pupil at or proximate the eye of the user by the at least one green hologram; and

converging a respective blue component of each instance of the first light signal that is received from the optical replicator to a respective exit pupil at or proximate the eye of the user by the at least one blue hologram.

22. The method of claim 21 wherein the holographic combiner includes a wavelength-multiplexed and angle-multiplexed holographic combiner that includes at least two angle-multiplexed red holograms, at least two angle-multiplexed green holograms, and at least two angle-multiplexed blue holograms, and wherein:

converging a respective red component of each instance of the first light signal that is received from the optical replicator to a respective exit pupil at or proximate the eye of the user by the at least one red hologram includes converging a respective red component of each instance of the first light signal that is received from the optical replicator to a respective exit pupil at or proximate the eye of the user by a respective angle-multiplexed red hologram;

converging a respective green component of each instance of the first light signal that is received from the optical replicator to a respective exit pupil at or proximate the eye of the user by the at least one green hologram includes converging a respective green component of each instance of the first light signal that is received from the optical replicator to a respective exit pupil at or proximate the eye of the user by a respective angle-multiplexed green hologram; and

converging a respective blue component of each instance of the first light signal that is received from the optical replicator to a respective exit pupil at or proximate the eye of the user by the at least one blue hologram includes converging a respective blue component of each instance of the first light signal that is received from the optical replicator to a respective exit pupil at or proximate the eye of the user by a respective angle-multiplexed blue hologram.

23. The method of claim 15, further comprising:

generating at least a second light signal by the scanning laser projector;

redirecting respective ones of N instances of the at least a second light signal towards the holographic combiner by the optical replicator; and

converging each instance of the at least a second light signal that is received from the optical replicator to a respective exit pupil at or proximate the eye of the user by the holographic combiner.

24. The method of claim 15, further comprising:

generating light signals corresponding to a sweep of a total scan range θ

by the scanning laser projector;

receiving the light signals corresponding to the total scan range θ

of the scanning laser projector by the optical replicator;

redirecting respective ones of N instances of the total scan range θ

of the scanning laser projector towards the holographic combiner by the optical replicator; and

converging each instance of the total scan range θ

of the scanning laser projector that is received from the optical replicator to a respective exit pupil at or proximate the eye of the user by the holographic combiner.

25. The method of claim 15 wherein the wearable heads-up display further comprises an eye tracker and at least one controllable shutter, the method further comprising:

determining a gaze direction of the eye of the user by the eye tracker; and

selectively blocking all but at least one of the N instances of the light signal redirected towards the holographic combiner from the optical replicator by the at least one controllable shutter, and wherein;

redirecting each instance of the first light signal that is received from the optical replicator towards the eye of the user by the holographic combiner includes, for the at least one of the N instances of the first light signal that is not blocked by the at least one controllable shutter, redirecting, by the holographic combiner, the at least one of the N instances of the first light signal towards a region of the eye of the user that contains a pupil of the eye of the user based on the gaze direction of the eye of the user determined by the eye tracker.

26. The method of claim 15 wherein the first light signal includes an image comprising at least two pixels and redirecting respective ones of N instances of the first light signal towards the holographic combiner by the optical replicator includes redirecting N respective instances of a same image towards the holographic combiner by the optical replicator.

27. The method of claim 15 wherein redirecting respective ones of N instances of the first light signal towards the holographic combiner by the optical replicator includes redirecting N respective instances of a same pixel in a different instance of a same image towards the holographic combiner by the optical replicator.