Systems, devices, and methods for eyebox expansion in wearable heads-up displays

• US 9,989,764 B2
• Filed: 02/17/2016
• Issued: 06/05/2018
• 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, Moore, Joshua
• Primary Examiner(s): Iluyomade, Ifedayo
• Application Number:
  US15/046,254
• Publication Number:
  US 20160377866A1
• Time in Patent Office: 839 Days
• Field of Search: None
• 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 wearable heads-up displays (“WHUDs”) are described. A WHUD includes a scanning laser projector (“SLP”), a holographic combiner, and an optical splitter positioned in the optical path therebetween. The optical splitter receives light signals generated by the SLP and separates the light signals into N sub-ranges based on the point of incidence of each light signal at the optical splitter. The optical splitter redirects the light signals corresponding to respective ones of the N sub-ranges towards the holographic combiner effectively from respective ones of N spatially-separated virtual positions for the SLP. The holographic combiner converges the light signals to respective ones 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, wherein the scanning laser projector has a total scan range Ω

in a first dimension, where 0°

<

Ω

<

180°

;

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 splitter carried by the support structure and positioned in an optical path between the scanning laser projector and the holographic combiner, the optical splitter comprising at least one optical element arranged to receive light signals generated by the scanning laser projector and redirect each light signal towards the holographic combiner effectively from one of N spatially-separated virtual positions for the scanning laser projector, where N is an integer greater than 1, the particular virtual position for the scanning laser projector from which a light signal is redirected by the optical splitter determined by a point of incidence at which the light signal is received by the optical splitter, wherein at least one optical element of the optical splitter is arranged to separate the total scan range Ω

of the scanning laser projector in the first dimension into X sub-ranges ω

_i in the first dimension, where 1<

X≤

N and

2. The wearable heads-up display of claim 1 wherein the scanning laser projector has a total two-dimensional scan range θ

and at least one optical element of the optical splitter is arranged to separate the total two-dimensional scan range θ

of the scanning laser projector into N two-dimensional sub-ranges φ

_i, where

3. The wearable heads-up display of claim 2 wherein at least one optical element of the optical splitter is arranged to:

receive light signals corresponding to a sweep of the total two-dimensional scan range θ

by the scanning laser projector;

separate the light signals corresponding to the sweep of the total two-dimensional scan range θ

into the N two-dimensional sub-ranges (p, based on point of incidence at the optical splitter; and

redirect the light signals corresponding to the sweep of the total two-dimensional scan range θ

towards the holographic combiner effectively from each of the N spatially-separated virtual positions for the scanning laser projector, the particular virtual position for the scanning laser projector from which each light signal in the sweep of the total two-dimensional scan range θ

is redirected by the optical splitter determined by the particular two-dimensional sub-range φ

_i to which the light signal corresponds.

4. The wearable heads-up display of claim 1 wherein at least one optical element of the optical splitter is arranged to:

receive light signals corresponding to a sweep of the total scan range Ω

in the first dimension by the scanning laser projector;

separate the light signals corresponding to the sweep of the total scan range Ω

in the first dimension into the X sub-ranges coin the first dimension based on point of incidence at the optical splitter; and

redirect the light signals corresponding to the sweep of the total scan range Ω

in the first dimension towards the holographic combiner effectively from at least X of the N spatially-separated virtual positions for the scanning laser projector, the particular virtual position for the scanning laser projector from which each light signal in the sweep of the total scan range Ω

in the first dimension is redirected by the optical splitter determined by the particular sub-range ω

_i in the first dimension to which the light signal corresponds.

5. The wearable heads-up display of claim 1 wherein the scanning laser projector has a total scan range ψ

in a second dimension, where 0°

<

ψ

<

180°

, and at least one optical element of the optical splitter is arranged to separate the total scan range ψ

of the scanning laser projector in the second dimension into Y sub-ranges β

_i in the second dimension, where 1<

Y≤

N and

6. The wearable heads-up display of claim 5 wherein at least one optical element of the optical splitter is arranged to:

receive light signals corresponding to a sweep of the total scan range ψ

in the second dimension by the scanning laser projector;

separate the light signals corresponding to the sweep of the total scan range ψ

in the second dimension into the Y sub-ranges β

_i in the second dimension based on point of incidence at the optical splitter; and

redirect the light signals corresponding to the sweep of the total scan range ψ

in the second dimension towards the holographic combiner effectively from at least Y of the N spatially-separated virtual positions for the scanning laser projector, the particular virtual position for the scanning laser projector from which a light signal in the sweep of the total scan range ψ

in the second dimension is redirected by the optical splitter determined by the particular sub-range β

_i in the second dimension to which the light signal corresponds.

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

8. The wearable heads-up display of claim 7, further comprising a prescription eyeglass lens, wherein the holographic combiner is carried by the prescription eyeglass lens.

9. The wearable heads-up display of claim 1 wherein the at least one hologram of the holographic combiner converges light signals to respective ones of N exit pupils at or proximate the eye of the user, the particular exit pupil determined by the particular virtual position for the scanning laser projector from which a light signal is redirected by the optical splitter.

10. The wearable heads-up display of claim 9 wherein the holographic combiner includes at least N multiplexed holograms, and wherein each one of the at least N multiplexed holograms converges light signals corresponding to a respective one of the N spatially-separated virtual positions for the scanning laser projector to a respective one of the N exit pupils at or proximate the eye of the user.

11. The wearable heads-up display of claim 9 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 for a light signal redirected from a particular one of the N spatially-separated virtual positions for the scanning laser projector by the optical splitter, the at least one red hologram converges a red component of the light signal to a particular one of the N exit pupils at or proximate the eye of the user, the at least one green hologram converges a green component of the light signal to the particular one of the N exit pupils at or proximate the eye of the user, and the at least one blue hologram converges a blue component of the light signal to the particular one of the N exit pupils at or proximate the eye of the user.

12. The wearable heads-up display of claim 11 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 red components of light signals redirected from a respective one of the N spatially-separated virtual positions for the scanning laser projector by the optical splitter 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 green components of light signals redirected from a respective one of the N spatially-separated virtual positions for the scanning laser projector by the optical splitter 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 blue components of light signals redirected from a respective one of the N spatially-separated virtual positions for the scanning laser projector by the optical splitter to a respective one of the N exit pupils at or proximate the eye of the user.

13. The wearable heads-up display of claim 9 wherein at least one of the scanning laser projector and/or the optical splitter is physically movable and/or rotatable on the support structure, and wherein physical movement and/or rotation of the scanning laser projector and/or optical splitter changes a position of at least one of the N exit pupils relative to the eye of the user.

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

15. The wearable heads-up display of claim 1 wherein at least one optical element of the optical splitter is arranged to receive N light signals generated by the scanning laser projector and redirect the N light signals towards the holographic combiner effectively from respective ones of the N spatially-separated virtual positions for the scanning laser projector, the particular virtual position for the scanning laser projector from which each one of the N light signals is redirected by the optical splitter determined by a respective point of incidence at which each light signal is received by the optical splitter, and wherein the holographic combiner comprises at least one hologram positioned and oriented to converge each one of the N light signals to a respective exit pupil at or proximate the eye of the user.

16. The wearable heads-up display of claim 15 wherein the N light signals include N different instances of a same image.

17. The wearable heads-up display of claim 15 wherein the N light signals include N different instances of a same pixel of an image.

18. The wearable heads-up display of claim 1 wherein the optical splitter comprises a faceted optical structure with at least N facets, and wherein at least one respective facet corresponds to each respective one of the N spatially-separated virtual positions for the scanning laser projector.

19. 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 and having a total two-dimensional scan range θ

including a total scan range Ω

in a first dimension, where 0°

<

Ω

<

180°

;

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;

an optical splitter carried by the support structure and positioned in an optical path between the scanning laser projector and the holographic combiner, wherein the optical splitter comprises at least one optical element arranged to;

receive light signals corresponding to a sweep of the total two-dimensional scan range θ

by the scanning laser projector;

separate the light signals into N two-dimensional sub-ranges φ

_i based on point of incidence at the optical splitter, where N is an integer greater than 1 and

20. The wearable heads-up display of claim 19 wherein the total two-dimensional scan range θ

of the scanning laser projector includes a total scan range ψ

in a second dimension, where 0°

<

ψ

<

180°

, and wherein at least one optical element of the optical splitter is arranged to;

receive light signals corresponding to at least one sweep of the total scan range ψ

in the second dimension by the scanning laser projector;

separate the light signals corresponding to the at least one sweep of the total scan range ψ

in the second dimension into Y sub-ranges β

_i in the second dimension based on point of incidence at the optical splitter, where 1<

Y≤

N and

21. A method of operating a wearable heads-up display, the wearable heads-up display including:

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

an optical splitter, 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, wherein the holographic combiner is a wavelength-multiplexed holographic combiner that includes at least N multiplexed red holograms, at least N multiplexed green holograms, and at least N multiplexed blue holograms, the method comprising;

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

receiving the first light signal at a first point of incidence by the optical splitter;

redirecting, by the optical splitter, the first light signal towards the holographic combiner effectively from a first one of N spatially-separated virtual positions for the scanning laser projector, where N is an integer greater than 1, the first virtual position for the scanning laser projector from which the first light signal is redirected by the optical splitter determined by the first point of incidence at which the first light signal is received by the optical splitter; and

converging the first light signal to a first one of N exit pupils at or proximate the eye of the user by the holographic combiner, wherein converging the first light signal to a first one of N exit pupils at or proximate the eye of the user by the holographic combiner includes;

converging the red component of the first light signal to the first exit pupil by one of the at least N red holograms, the one of the at least N red holograms determined by the first virtual position for the scanning laser projector from which the first light signal is redirected by the optical splitter;

converging the green component of the first light signal to the first exit pupil by one of the at least N green holograms, the one of the at least N green holograms determined by the first virtual position for the scanning laser projector from which the first light signal is redirected by the optical splitter; and

converging the blue component of the first light signal to the first exit pupil by one of the at least N blue holograms, the one of the at least N blue holograms determined by the first virtual position for the scanning laser projector from which the first light signal is redirected by the optical splitter, wherein the first exit pupil to which the first light signal is converged by the holographic combiner is determined by the first virtual position for the scanning laser projector from which the first light signal is redirected by the optical splitter.

22. The method of claim 21 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:

converging a red component of the first light signal to the first exit pupil by the at least one red hologram includes converging the red component of the first light signal to the first exit pupil by a first one of the N angle-multiplexed red holograms, the first angle-multiplexed red hologram by which the red component of the first light signal is converged determined by the first virtual position for the scanning laser projector from which the first light signal is redirected by the optical splitter;

converging a green component of the first light signal to the first exit pupil by the at least one green hologram includes converging the green component of the first light signal to the first exit pupil by a first one of the N angle-multiplexed green holograms, the first angle-multiplexed green hologram by which the green component of the first light signal is converged determined by the first virtual position for the scanning laser projector from which the first light signal is redirected by the optical splitter; and

converging a blue component of the first light signal to the first exit pupil by the at least one blue hologram includes converging the blue component of the first light signal to the first exit pupil by a first one of the N angle-multiplexed blue holograms, the first angle-multiplexed blue hologram by which the blue component of the first light signal is converged determined by the first virtual position for the scanning laser projector from which the first light signal is redirected by the optical splitter.

23. The method of claim 21, further comprising:

generating a second light signal by the scanning laser projector;

receiving the second light signal at a second point of incidence by the optical splitter;

redirecting, by the optical splitter, the second light signal towards the holographic combiner effectively from a second one of the N spatially-separated virtual positions for the scanning laser projector, the second virtual position for the scanning laser projector from which the second light signal is redirected by the optical splitter determined by the second point of incidence at which the second light signal is received by the optical splitter; and

converging the second light signal to a second one of the N exit pupils at or proximate the eye of the user by the holographic combiner.

24. The method of claim 23 wherein:

the scanning laser projector has a total scan range θ

;

receiving the first light signal at a first point of incidence by the optical splitter includes receiving, by the optical splitter, the first light signal at a first point of incidence that is included in a first one φ

₁ of N sub-ranges φ

_i of the total scan range θ

for the scanning laser projector, where

25. The method of claim 21 wherein generating a first light signal by the scanning laser projector includes generating a first instance of an image by the scanning laser projector, the first instance of the image including at least two pixels.

26. The method of claim 21 wherein generating a first light signal by the scanning laser projector includes generating a first instance of a first pixel of an image by the scanning laser projector.