U.S. patent application number 16/143030 was filed with the patent office on 2019-03-28 for systems, devices, and methods for waveguide-based eyebox expansion in wearable heads-up displays.
The applicant listed for this patent is THALMIC LABS INC.. Invention is credited to Stefan Alexander, Timothy Paul Bodiya, Stuart James Myron Nicholson.
Application Number | 20190094549 16/143030 |
Document ID | / |
Family ID | 65807352 |
Filed Date | 2019-03-28 |
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United States Patent
Application |
20190094549 |
Kind Code |
A1 |
Nicholson; Stuart James Myron ;
et al. |
March 28, 2019 |
SYSTEMS, DEVICES, AND METHODS FOR WAVEGUIDE-BASED EYEBOX EXPANSION
IN WEARABLE HEADS-UP DISPLAYS
Abstract
Systems, devices, and methods for eyebox expansion in wearable
heads-up displays ("WHUDs") are described. The WHUDs described
herein each include a projector and an optical waveguide positioned
in an optical path between the projector and an eye of the user.
For any given light signal from the projector, the optical
waveguide receives the light signal at an input coupler and outputs
multiple instances or copies of the light signal from multiple
discrete, spatially-separated output couplers. The multiple
instances or copies of the light signal may be converged by the
optical waveguide directly to respective exit pupils at the user's
eye or may be routed by the optical waveguide to a holographic
combiner in the user's field of view from which the light signals
may be converged to respective exit pupils at the user's eye. The
optical waveguide employs exit pupil replication to expand the
eyebox of the WHUD.
Inventors: |
Nicholson; Stuart James Myron;
(Waterloo, CA) ; Bodiya; Timothy Paul; (Toronto,
CA) ; Alexander; Stefan; (Elmira, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
THALMIC LABS INC. |
Kitchener |
|
CA |
|
|
Family ID: |
65807352 |
Appl. No.: |
16/143030 |
Filed: |
September 26, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62564858 |
Sep 28, 2017 |
|
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|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02B 2027/0187 20130101;
G02B 27/0172 20130101; G02B 6/00 20130101; G02B 2027/0178 20130101;
G02B 6/0033 20130101; G02B 27/0176 20130101; G02B 2027/015
20130101; G02B 27/0081 20130101; G02B 6/0013 20130101; G02B
2027/0174 20130101; G02B 27/0179 20130101 |
International
Class: |
G02B 27/01 20060101
G02B027/01; F21V 8/00 20060101 F21V008/00; G02B 27/00 20060101
G02B027/00 |
Claims
1. An optical waveguide comprising: a volume of optically
transparent material; a first input coupler carried by the volume
of optically transparent material and positioned and oriented to
couple light from a light source into the volume of optically
transparent material; a first output coupler carried by the volume
of optically transparent material, the first output coupler
positioned and oriented to couple a first portion of light from the
light source out of the volume of optically transparent material
and direct the first portion of light to a first exit pupil; and a
second output coupler carried by the volume of optically
transparent material and spatially-separated from the first output
coupler, the second output coupler positioned and oriented to
couple a second portion of light from the light source out of the
volume of optically transparent material and direct the second
portion of light to a second exit pupil, the second exit pupil
spatially-separated from the first exit pupil.
2. The optical waveguide of claim 1 wherein the volume of optically
transparent material is positioned and oriented to guide both the
first portion of light and the second portion of light towards the
first output coupler, and wherein the first output coupler is
oriented to redirect the second portion of light towards the second
output coupler through the volume of optically transparent
material.
3. The optical waveguide of claim 2 wherein the first output
coupler is at least partially reflective of the first portion of
light and at least partially transmissive of the second portion of
light.
4. The optical waveguide of claim 1 wherein the volume of optically
transparent material is positioned and oriented to guide the first
portion of light directly towards the first output coupler without
impinging on the second output coupler and to guide the second
portion of light directly towards the second output coupler without
impinging on the first output coupler.
5. The optical waveguide of claim 1 wherein at least one of the
first input coupler, the first output coupler, and the second
output coupler is selected from a group consisting of: an optical
grating, a diffraction grating, a hologram, and a holographic
optical element comprising at least two holograms.
6. The optical waveguide of claim 1, further comprising an eyeglass
lens, wherein the volume of optically transparent material is
integrated with the eyeglass lens.
7. The optical waveguide of claim 1 wherein the volume of optically
transparent material includes a single optical channel through
which the first portion of light and the second portion of light
are both guided.
8. The optical waveguide of claim 1 wherein the volume of optically
transparent material includes a first optical channel through which
the first portion of light is guided towards the first output
coupler and a second optical channel through which the second
portion of light is guided towards the second output coupler, and
wherein the first portion of light is not guided through the second
optical channel and the second portion of light is not guided
through the first optical channel.
9. The optical waveguide of claim 1, further comprising: N output
couplers carried by the volume of optically transparent material,
wherein N is an integer greater than 2, and wherein each respective
one of the N output couplers is oriented to couple a respective
portion of light from the light source out of the volume of
optically transparent material and direct the respective portion of
light to a respective one of N exit pupils.
10. The optical waveguide of claim 9 wherein the N output couplers
are arranged in a single row across a length of the volume of
optically transparent material, and wherein each of the N output
couplers is at least partially reflective to couple a respective
portion of light from the light source out of the volume of
optically transparent material and direct the respective portion of
light to a respective one of the N exit pupils, and each of at
least N-1 of the output couplers is partially transmissive to
transmit a respective portion of light from the light source
through the volume of optically transparent material towards at
least one other one of the N output couplers.
11. The optical waveguide of claim 9 wherein: the N output couplers
are arranged in an array having P>1 rows and Q>1 columns; the
volume of optically transparent material is positioned and oriented
to guide a respective portion of light from the light source to
each respective one of the N output couplers; the Q output couplers
in each respective one of the P rows are arranged in a row; each of
the Q output couplers in each of the P rows is at least partially
reflective to couple a respective portion of light from the light
source out of the volume of optically transparent material and
direct the respective portion of light to a respective one of the N
exit pupils; and each of at least Q-1 of the Q output couplers in
each of the P rows is partially transmissive to transmit a
respective portion of light from the light source through the
volume of optically transparent material towards at least one other
one of the Q output couplers in the row.
12. The optical waveguide of claim 11 wherein the volume of
optically transparent material includes P optical channels and each
of the P rows corresponds to a respective one of the P
channels.
13. The optical waveguide of claim 1, further comprising a second
input coupler oriented to couple light from the light source into
the volume of optically transparent material, wherein the first
input coupler is positioned and oriented to couple the first
portion of light from the light source into the volume of optically
transparent material and direct the first portion of light from the
light source towards the first output coupler and the second input
coupler is positioned and oriented to couple the second portion of
light from the light source into the volume of optically
transparent material and direct the second portion of light from
the light source towards the second output coupler.
Description
TECHNICAL FIELD
[0001] The present systems, devices, and methods generally relate
to wearable heads-up display technologies and particularly relate
to expanding the eyebox of a wearable heads-up display.
BACKGROUND
Description of the Related Art
Wearable Heads-Up Displays
[0002] A head-mounted display is an electronic device that is worn
on a user's head and, when so worn, secures at least one electronic
display within a viewable field of at least one of the user's eyes,
regardless of the position or orientation of the user's head. A
wearable heads-up display is a head-mounted display that enables
the user to see displayed content but also does not prevent the
user from being able to see their external environment. The
"display" component of a wearable heads-up display is either
transparent or at a periphery of the user's field of view so that
it does not completely block the user from being able to see their
external environment. Examples of wearable heads-up displays
include: the Google Glass.RTM., the Optinvent Ora.RTM., the Epson
Moverio.RTM., and the Sony Glasstron.RTM., just to name a few.
[0003] The optical performance of a wearable heads-up display is an
important factor in its design. When it comes to face-worn devices,
however, users also care a lot about aesthetics. This is clearly
highlighted by the immensity of the eyeglass (including sunglass)
frame industry. Independent of their performance limitations, many
of the aforementioned examples of wearable heads-up displays have
struggled to find traction in consumer markets because, at least in
part, they lack fashion appeal. Most wearable heads-up displays
presented to date employ large display components and, as a result,
most wearable heads-up displays presented to date are considerably
bulkier and less stylish than conventional eyeglass frames.
[0004] A challenge in the design of wearable heads-up displays is
to minimize the bulk of the face-worn apparatus will still
providing displayed content with sufficient visual quality. There
is a need in the art for wearable heads-up displays of more
aesthetically-appealing design that are capable of providing
high-quality images to the user without limiting the user's ability
to see their external environment.
Eyebox
[0005] In near-eye optical devices such as rifle scopes and
wearable heads-up displays, the range of eye positions (relative to
the device itself) over which specific content/imagery provided by
the device is visible to the user is generally referred to as the
"eyebox." An application in which content/imagery is only visible
from a single or small range of eye positions has a "small eyebox"
and an application in which content/imagery is visible from a wider
range of eye positions has a "large eyebox." The eyebox may be
thought of as a volume in space positioned near the optical device.
When the eye of the user (and more particularly, the pupil of the
eye of the user) is positioned inside this volume and facing the
device, the user is able to see all of the content/imagery provided
by the device. When the eye of the user is positioned outside of
this volume, the user is not able to see at least some of the
content/imagery provided by the device.
[0006] The geometry (i.e., size and shape) of the eyebox is an
important property that can greatly affect the user experience for
a wearable heads-up display. For example, if the wearable heads-up
display has a small eyebox that centers on the user's pupil when
the user is gazing directly ahead, some or all content displayed by
the wearable heads-up display may disappear for the user when the
user gazes even slightly off-center, such as slightly to the left,
slightly to the right, slightly up, or slightly down. Furthermore,
if a wearable heads-up display that has a small eyebox is designed
to align that eyebox on the pupil for some users, the eyebox will
inevitably be misaligned relative to the pupil of other users
because not all users have the same facial structure. Unless a
wearable heads-up display is deliberately designed to provide a
glanceable display (i.e., a display that is not always visible but
rather is only visible when the user gazes in a certain direction),
it is generally advantageous for a wearable heads-up display to
have a large eyebox.
[0007] Demonstrated techniques for providing a wearable heads-up
display with a large eyebox generally necessitate adding more bulky
optical components to the display. Technologies that enable a
wearable heads-up display of minimal bulk (relative to conventional
eyeglass frames) to provide a large eyebox are generally lacking in
the art.
BRIEF SUMMARY
[0008] A wearable heads-up display may be summarized as including:
a support structure that in use is worn on a head of a user; an
eyeglass lens carried by the support structure and positioned in a
field of view of an eye of the user when the support structure is
worn on the head of the user; a projector to project light, the
projector carried by the support structure; an optical waveguide
carried by the support structure, wherein the optical waveguide
comprises: an input coupler carried by the optical waveguide and
positioned in an optical path of light projected by the projector,
the input coupler oriented to couple light from the projector into
the optical waveguide; a first output coupler carried by the
optical waveguide, the first output coupler oriented to couple a
first portion of light from the projector out of the optical
waveguide and direct the first portion of light to a first exit
pupil at or proximate the eye of the user; and a second output
coupler carried by the optical waveguide, the second output coupler
oriented to couple a second portion of light from the projector out
of the optical waveguide and direct the second portion of light to
a second exit pupil at or proximate the eye of the user.
[0009] The optical waveguide may be carried by the eyeglass lens
and positioned at least partially within a field of view of an eye
of the user when the support structure is worn on the head of the
user. The first output coupler may be positioned within the field
of view of the eye of the user when the support structure is worn
on the head of the user and oriented to converge the first portion
of light directly towards the first exit pupil at or proximate the
eye of the user. The second output coupler may be positioned within
the field of view of the eye of the user when the support structure
is worn on the head of the user and oriented to converge the second
portion of light directly towards the second exit pupil at or
proximate the eye of the user. The projector may be carried by an
arm portion of the support structure and oriented to project light
through free space towards the eyeglass lens. The input coupler may
be positioned within the field of view of the eye of the user when
the support structure is worn on the head of the user and oriented
to receive light from the projector.
[0010] The optical waveguide may be carried by an arm portion of
the support structure and positioned substantially outside of a
field of an eye of the user when the support structure is worn on
the head of the user. In this case, the wearable heads-up display
may further include: a holographic combiner carried by the eyeglass
lens and positioned within the field of view of the eye of the user
when the support structure is worn on the head of the user, the
holographic combiner including at least one hologram, wherein: the
first output coupler is positioned and oriented to direct the first
portion of light through free space towards the holographic
combiner; the second output coupler is positioned and oriented to
direct the second portion of light through free space towards the
holographic combiner; and the holographic combiner is positioned
and oriented to: receive the first portion of light from the first
output coupler; converge the first portion of light towards the
first exit pupil at or proximate the eye of the user; receive the
second portion of light from the second output coupler; and
converge the second portion of light towards the second exit pupil
at or proximate the eye of the user. The holographic combiner may
be integrated with the eyeglass lens.
[0011] The optical waveguide may be positioned and oriented to
guide both the first portion of light and the second portion of
light towards the first output coupler, and the first output
coupler may be oriented to redirect the second portion of light
towards the second output coupler through the optical waveguide.
The first output coupler may be at least partially reflective of
the first portion of light and at least partially transmissive of
the second portion of light.
[0012] The optical waveguide may be positioned and oriented to
guide the first portion of light directly towards the first output
coupler without impinging on the second output coupler and to guide
the second portion of light directly towards the second output
coupler without impinging on the first output coupler.
[0013] At least one of the input coupler, the first output coupler,
and the second output coupler may be selected from a group
consisting of: an optical grating, a diffraction grating, a
hologram, and a holographic optical element comprising at least two
holograms. The optical waveguide may be integrated with the
eyeglass lens. The optical waveguide may include a single optical
channel through which the first portion of light and the second
portion of light are both guided. Alternatively, the optical
waveguide may include a first optical channel through which the
first portion of light is guided towards the first output coupler
and a second optical channel through which the second portion of
light is guided towards the second output coupler, wherein the
first portion of light is not guided through the second optical
channel and the second portion of light is not guided through the
first optical channel.
[0014] The wearable heads-up display may further include: N output
couplers carried by the optical waveguide, wherein N is an integer
greater than 2, and wherein each respective one of the N output
couplers is oriented to couple a respective portion of light from
the projector out of the optical waveguide and direct the
respective portion of light to a respective one of N exit pupils at
or proximate the eye of the user. The N output couplers may be
arranged in a single row across a length of the optical waveguide,
and each of the N output couplers may be at least partially
reflective to couple a respective portion of light from the
projector out of the optical waveguide and direct the respective
portion of light to a respective one of the N exit pupils at or
proximate the eye of the user. Each of at least N-1 of the output
couplers may be partially transmissive to transmit a respective
portion of light from the projector through the optical waveguide
towards at least one other one of the N output couplers.
[0015] Alternatively, the N output couplers may be arranged in an
array having P>1 rows and Q>1 columns. The optical waveguide
may be positioned and oriented to guide a respective portion of
light from the projector to each respective one of the N output
couplers. The Q output couplers in each respective one of the P
rows may be arranged in a row. Each of the Q output couplers in
each of the P rows may be at least partially reflective to couple a
respective portion of light from the projector out of the optical
waveguide and direct the respective portion of light to a
respective one of the N exit pupils at or proximate the eye of the
user. Each of at least Q-1 of the Q output couplers in each of the
P rows may be partially transmissive to transmit a respective
portion of light from the projector through the optical waveguide
towards at least one other one of the Q output couplers in the row.
The optical waveguide may include P optical channels and each of
the P rows may correspond to a respective one of the P
channels.
[0016] The projector may include a scanning laser projector. The
support structure may have a general shape and appearance of an
eyeglasses frame.
[0017] The input coupler may be a first input coupler, and the
wearable heads-up display may further include a second input
coupler oriented to couple light from the projector into the
optical waveguide, wherein the first input coupler is positioned
and oriented to couple the first portion of light from the
projector into the optical waveguide and direct the first portion
of light from the projector towards the first output coupler and
the second input coupler is positioned and oriented to couple the
second portion of light from the projector into the optical
waveguide and direct the second portion of light from the projector
towards the second output coupler.
[0018] An optical waveguide may be summarized as including: a
volume of optically transparent material; a first input coupler
carried by the volume of optically transparent material and
positioned and oriented to couple light from a light source into
the volume of optically transparent material; a first output
coupler carried by the volume of optically transparent material,
the first output coupler positioned and oriented to couple a first
portion of light from the light source out of the volume of
optically transparent material and direct the first portion of
light to a first exit pupil; and a second output coupler carried by
the volume of optically transparent material and
spatially-separated from the first output coupler, the second
output coupler positioned and oriented to couple a second portion
of light from the light source out of the volume of optically
transparent material and direct the second portion of light to a
second exit pupil, the second exit pupil spatially-separated from
the first exit pupil.
[0019] The volume of optically transparent material may be
positioned and oriented to guide both the first portion of light
and the second portion of light towards the first output coupler,
and the first output coupler may be oriented to redirect the second
portion of light towards the second output coupler through the
volume of optically transparent material. The first output coupler
may be at least partially reflective of the first portion of light
and at least partially transmissive of the second portion of
light.
[0020] The volume of optically transparent material may be
positioned and oriented to guide the first portion of light
directly towards the first output coupler without impinging on the
second output coupler and to guide the second portion of light
directly towards the second output coupler without impinging on the
first output coupler.
[0021] At least one of the first input coupler, the first output
coupler, and the second output coupler may be selected from a group
consisting of: an optical grating, a diffraction grating, a
hologram, and a holographic optical element comprising at least two
holograms.
[0022] The optical waveguide may further include an eyeglass lens,
wherein the volume of optically transparent material is integrated
with the eyeglass lens.
[0023] The volume of optically transparent material may include a
single optical channel through which the first portion of light and
the second portion of light are both guided. Alternatively, the
volume of optically transparent material may include a first
optical channel through which the first portion of light is guided
towards the first output coupler and a second optical channel
through which the second portion of light is guided towards the
second output coupler, wherein the first portion of light is not
guided through the second optical channel and the second portion of
light is not guided through the first optical channel.
[0024] The optical waveguide may further include N output couplers
carried by the volume of optically transparent material, wherein N
is an integer greater than 2, and wherein each respective one of
the N output couplers is oriented to couple a respective portion of
light from the light source out of the volume of optically
transparent material and direct the respective portion of light to
a respective one of N exit pupils. The N output couplers may be
arranged in a single row across a length of the volume of optically
transparent material, wherein each of the N output couplers is at
least partially reflective to couple a respective portion of light
from the light source out of the volume of optically transparent
material and direct the respective portion of light to a respective
one of the N exit pupils, and each of at least N-1 of the output
couplers is partially transmissive to transmit a respective portion
of light from the light source through the volume of optically
transparent material towards at least one other one of the N output
couplers. Alternatively, the N output couplers may be arranged in
an array having P>1 rows and Q>1 columns, wherein: the volume
of optically transparent material is positioned and oriented to
guide a respective portion of light from the light source to each
respective one of the N output couplers; the Q output couplers in
each respective one of the P rows are arranged in a row; each of
the Q output couplers in each of the P rows is at least partially
reflective to couple a respective portion of light from the light
source out of the volume of optically transparent material and
direct the respective portion of light to a respective one of the N
exit pupils; and each of at least Q-1 of the Q output couplers in
each of the P rows is partially transmissive to transmit a
respective portion of light from the light source through the
volume of optically transparent material towards at least one other
one of the Q output couplers in the row. The volume of optically
transparent material may include P optical channels and each of the
P rows may correspond to a respective one of the P channels.
[0025] The optical waveguide may further include a second input
coupler oriented to couple light from the light source into the
volume of optically transparent material, wherein the first input
coupler is positioned and oriented to couple the first portion of
light from the light source into the volume of optically
transparent material and direct the first portion of light from the
light source towards the first output coupler and the second input
coupler is positioned and oriented to couple the second portion of
light from the light source into the volume of optically
transparent material and direct the second portion of light from
the light source towards the second output coupler.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0026] In the drawings, identical reference numbers identify
similar elements or acts. The sizes and relative positions of
elements in the drawings are not necessarily drawn to scale. For
example, the shapes of various elements and angles are not
necessarily drawn to scale, and some of these elements are
arbitrarily enlarged and positioned to improve drawing legibility.
Further, the particular shapes of the elements as drawn are not
necessarily intended to convey any information regarding the actual
shape of the particular elements, and have been solely selected for
ease of recognition in the drawings.
[0027] FIG. 1 is a partial-cutaway perspective view of a wearable
heads-up display that provides a large eyebox made up of multiple
optically-replicated exit pupils in accordance with the present
systems, devices, and methods.
[0028] FIG. 2 is a partial-cutaway perspective view of a wearable
heads-up display that provides a large eyebox made up of multiple
optically-replicated exit pupils in accordance with the present
systems, devices, and methods.
[0029] FIG. 3 is an illustrative diagram showing an example of an
optical waveguide in accordance with the present systems, devices,
and methods.
[0030] FIG. 4 is an illustrative diagram showing an example of an
optical waveguide in accordance with the present systems, devices,
and methods.
DETAILED DESCRIPTION
[0031] In the following description, certain specific details are
set forth in order to provide a thorough understanding of various
disclosed embodiments. However, one skilled in the relevant art
will recognize that embodiments may be practiced without one or
more of these specific details, or with other methods, components,
materials, etc. In other instances, well-known structures
associated with portable electronic devices and head-worn devices,
have not been shown or described in detail to avoid unnecessarily
obscuring descriptions of the embodiments.
[0032] Unless the context requires otherwise, throughout the
specification and claims which follow, the word "comprise" and
variations thereof, such as, "comprises" and "comprising" are to be
construed in an open, inclusive sense, that is as "including, but
not limited to."
[0033] Reference throughout this specification to "one embodiment"
or "an embodiment" means that a particular feature, structures, or
characteristics may be combined in any suitable manner in one or
more embodiments.
[0034] As used in this specification and the appended claims, the
singular forms "a," "an," and "the" include plural referents unless
the content clearly dictates otherwise. It should also be noted
that the term "or" is generally employed in its broadest sense,
that is as meaning "and/or" unless the content clearly dictates
otherwise.
[0035] The headings and Abstract of the Disclosure provided herein
are for convenience only and do not interpret the scope or meaning
of the embodiments.
[0036] The various embodiments described herein provide systems,
devices, and methods for eyebox expansion in wearable heads-up
displays ("WHUDs"). Particularly, the various embodiments described
in the present systems, devices, and methods provide optical
waveguide-based structures and techniques that are operable to
expand the eyebox of a projector-based WHUD. For the purposes of
the present systems, devices, and methods, a "projector" is any
light or image source that functions by projecting light or images
directly to at least one eye of a user and includes, without
limitation: a scanning laser projector, a digital light processor
or "DLP"-based projector, an LCD- or SLM-based projector, and/or a
LED-based projector.
[0037] Generally, a projector-based WHUD is a form of virtual
retina display in which a projector projects an image (e.g., draws
a raster scan in the case of a scanning laser projector), either
directly or through any number of intervening optics, onto the eye
of the user. In the absence of any further measure the projector
projects light over a fixed area called the exit pupil of the
display. In order for the user to see displayed content the exit
pupil of the display typically needs to align with, be encompassed
by, or overlap with the entrance pupil of the user's eye. The full
scan range of the projector (i.e., the full resolution and/or field
of view of the display) is visible to the user when the exit pupil
of the display is completely contained within the entrance pupil of
the eye. For this reason, a projector-based WHUD typically employs
a relatively small exit pupil that is equal to or smaller than the
expected size of the entrance pupil of the user's eye (e.g., less
than or equal to about 4 mm in diameter).
[0038] The eyebox of a projector-based WHUD is defined, at least in
part, by the geometry of one or more exit pupil(s) of the display
at or proximate the eye of the user. A projector-based WHUD that
employs a small exit pupil in order to achieve maximum display
resolution and/or field of view typically has the drawback of
having a relatively small eyebox. For example, the exit pupil may
be aligned with the center of the user's eye so that the eye's
pupil is located "within the eyebox" when the user is gazing
directly ahead, but the eye's pupil may quickly leave the eyebox if
and when the user glances anywhere off-center. A larger eyebox may
be achieved by increasing the size of the exit pupil but this
typically comes at the cost of reducing the display resolution
and/or field of view. In accordance with the present systems,
devices, and methods, the eyebox of a projector-based WHUD may be
expanded by optically replicating and/or repeating a relatively
small exit pupil and spatially distributing multiple copies or
instances of the exit pupil over a relatively larger area of the
user's eye, compared to the area of the single exit pupil on its
own. In this way, at least one complete instance of the display
exit pupil (either as a single instance in its entirety or as a
combination of respective portions of multiple instances) may be
contained within the perimeter of the eye's entrance pupil for each
of a range of eye positions corresponding to a range of gaze
directions of the user. In other words, the present systems,
devices, and methods describe eyebox expansion by exit pupil
replication in projector-based WHUDs.
[0039] Throughout this specification and the appended claims, the
term "replication" is used (e.g., in the context of "exit pupil
replication") to generally refer to situations where multiple
instances of substantially the same thing (e.g., an exit pupil) are
produced. The term "exit pupil replication" is intended to
generally encompass approaches that produce concurrent (e.g.,
temporally parallel) instances of an exit pupil as well as
approaches that produce sequential (e.g., temporally serial or
"repeated") instances of an exit pupil.
[0040] The various embodiments described herein may at least
partially employ and/or may be implemented instead of, in addition
to, or in combination with, the systems, devices, and methods
described in US Patent Application Publication No. US 2016-0377865
A1, US Patent Application Publication No. US 2016-0377866 A1,
and/or US Patent Application Publication No. US 2016-0238845 A1. In
some implementations, the present systems, devices, and methods
provide a combination of the "splitting" and "replicating" concepts
described in the above-listed patent publications.
[0041] FIG. 1 is a partial-cutaway perspective view of a WHUD 100
that provides a large eyebox made up of multiple
optically-replicated exit pupils in accordance with the present
systems, devices, and methods. WHUD 100 includes a support
structure 110 that in use is worn on the head of a user and has a
general shape and appearance of an eyeglasses (e.g., sunglasses)
frame. Support structure 110 carries multiple components, including
a projector 120 and an optical waveguide 130. Projector 120 may
include a scanning laser projector as previously described. Optical
waveguide 130 itself includes an input coupler 131, a first output
coupler 132, and at least a second output coupler 133. At least one
of the input coupler, the first output coupler, and the second
output coupler is selected from a group consisting of: an optical
grating, a diffraction grating, a hologram, and a holographic
optical element comprising at least two holograms.
[0042] A person of skill in the art will appreciate that optical
waveguide 130 may include an optical fiber or a rectangular
waveguide or lightguide formed of a volume of optically transparent
material such as glass or polymer.
[0043] Projector 120, in operation, projects display light 101
towards optical waveguide 130. Input coupler 131 of optical
waveguide 130 is positioned in an optical path of projector 120
(i.e., in an optical path of light 101 from projector 120) and
oriented to couple light 101 from projector 120 into optical
waveguide 130. Light 101 is then propagated through an inner volume
of optical waveguide 130 (e.g., via total internal reflection)
until it encounters first output coupler 132. First output coupler
132 is oriented to: i) couple a first portion 101a of light 101
from projector 120 out of optical waveguide 130, and ii) direct
first portion 101a of light 101 to a first exit pupil 140a at or
proximate the eye of the user (not shown to reduce clutter).
[0044] At least a second portion 101b of light 101 is propagated
through optical waveguide 130 until it encounters second output
coupler 133. Second output coupler 133 is oriented to: i) couple
second portion 101b of light 101 from projector 120 out of optical
waveguide 130, and ii) direct second portion 101b of light 101 to a
second exit pupil 140b at or proximate the eye of the user.
[0045] Thus, respective first and second portions 101a, 101b of the
same display light 101 are replicated and routed to respective exit
pupils 140a and 140b at or proximate the eye of the user. First
exit pupil 140a and second exit pupil 140b are spatially separated
from one another at or proximate the eye of the user and,
therefore, in combination provide an expanded eyebox relative to
the size of the eyebox corresponding to either first exit pupil
140a or second exit pupil 140b on its own.
[0046] Generally, support structure 110 carries an eyeglass lens
150 positioned in the field of view of the eye of the user when
support structure 110 is worn on the head of the user. Eyeglass
lens 150 may include, for example, a prescription eyeglass lens. In
the illustrated embodiment of FIG. 1, optical waveguide 130 is
integrated with eyeglass lens 150 and positioned at least partially
within the field of view of the eye of the user when support
structure 110 is worn on the head of the user. In this
configuration, input coupler 131 is positioned within the field of
view of the eye of the user when support structure 110 is worn on
the head of the user, and display light 101 is projected from an
arm portion of support structure 110, through free space, to
impinge on input coupler 131 and couple into optical waveguide 130
therethrough. For the purposes of the present systems, devices, and
methods, the term "free space" is used to refer to a three
dimensional volume that is outside of (i.e., external to) the
various systems and devices described herein. For example, in FIG.
1 "free space" refers to the volume outside of (i.e., external to)
wearable heads-up display 100, and includes the portion of the
optical path of light 101 that extends from projector 120 to input
coupler 131 between the arm portion of support structure 110 and
eyeglass lens 150.
[0047] Similar to input coupler 131, first output coupler 132 is
also positioned within the field of view of the eye of the user
when support structure 110 is worn on the head of the user and
oriented to converge first portion 101a of light 101 directly
(i.e., with no intervening optics) towards first exit pupil 140a at
or proximate the eye of the user, and second output coupler 133 is
also positioned within the field of view of the eye of the user
when support structure 110 is worn on the head of the user and
oriented to converge second portion 101b of light 101 directly
(i.e., with no intervening optics) towards second exit pupil 140b
at or proximate the eye of the user.
[0048] The configuration described above and illustrated in FIG. 1
may employ systems, devices, and/or methods of integrating
waveguide structures with curved eyeglass lenses, such as for
example those described in U.S. Provisional Patent Application Ser.
No. 62/482,062 (now U.S. patent application Ser. Nos. 15/946,549,
15/946,557, 15/946,562, 15/946,565, and 15/946,569). However, in
some implementations (e.g., where a prescription of lens 150
renders integration of waveguide 130 therewith difficult) it may be
advantageous to employ an alternative implementation such as that
described in FIG. 2.
[0049] FIG. 2 is a partial-cutaway perspective view of a WHUD 200
that provides a large eyebox made up of multiple
optically-replicated exit pupils in accordance with the present
systems, devices, and methods. WHUD 200 is substantially similar to
WHUD 100 from FIG. 1 in that it includes a support structure 210
that in use is worn on the head of a user and has a general shape
and appearance of an eyeglasses (e.g., sunglasses) frame and that
support structure 210 carries a projector 220 and an optical
waveguide 230. However, WHUD 200 is distinct from WHUD 100 in that
optical waveguide 230 is positioned substantially outside of the
field of view of the eye of the user when support structure 210 is
worn on the head of the user, and in that WHUD 200 includes a
holographic combiner 260.
[0050] Holographic combiner 260 is carried by support structure 210
and is positioned within the field of view of the eye of the user
when support structure 210 is worn on the head of the user.
Holographic combiner 260 includes at least one hologram, is
integrated with eyeglass lens 250, and may implement any or all of
the systems, devices, and methods described in US Patent
Application Publication No. US 2017-0212349 A1, US Patent
Application Publication No. US 2016-0327797 A1, US Patent
Application Publication No. US 2016-0327796 A1, US Patent
Application Publication No. US 2016-0349516 A1, US Patent
Application Publication No. US 2017-0068095 A1, US Patent
Application Publication No. US 2017-0212290 A1, US Patent
Application Publication No. US 2017-0219829 A1, U.S. Provisional
Patent Application Ser. No. 62/487,303, and/or U.S. Provisional
Patent Application Ser. No. 62/534,099.
[0051] In the configuration of WHUD 200, optical waveguide 230 is
positioned substantially outside of the user's field of view (e.g.,
on an arm or temple of support structure 210). Though similar to
optical waveguide 130 of WHUD 100, optical waveguide 230 of WHUD
200 still includes input coupler 231, first output coupler 232, and
at least second output coupler 233. In WHUD 100, first output
coupler 132 and second output coupler 133 each converge respective
portions 101a, 101b of light 101 directly (i.e., without any
intervening optics) towards respective exit pupils 140a, 140b at or
proximate the eye of the user. In WHUD 200, first output coupler
232 and second output coupler 233 also direct respective portions
201a, 201b of light 201 from projector 220 to respective exit
pupils 240a, 240b at or proximate the eye of the user, but in the
configuration of WHUD 200 the optical paths of first and second
light portions 201a, 201b are both interrupted by holographic
combiner 260 in between output couplers 232, 233 and exit pupils
240a, 240b. In other words, first output coupler 232 is positioned
and oriented to direct first portion 201a of light 201 towards
holographic combiner 260 and second output coupler 233 is
positioned and oriented to direct second portion 201b of light 201
towards holographic combiner 260. First output coupler 232 and
second output coupler 233 may or may not respectively converge
first and second portions 201a, 201b of light 201. Holographic
combiner 260 itself is positioned and oriented to: i) receive first
portion 201a of light 201 from first output coupler 232 and
converge first portion 201a of light 201 towards first exit pupil
240a at or proximate the eye of the user; and ii) receive second
portion 201b of light 201 from second output coupler 233 and
converge second portion 201b of light 201 towards second exit pupil
240b at or proximate the eye of the user. That is, holographic
combiner 260 mediates propagation of light 201 in between optical
waveguide 230 (specifically, output couplers 232 and 233 thereof)
and the exit pupils (240a, 240b) of WHUD 200.
[0052] The configuration of WHUD 200 may be similar to that
described in US Patent Publication US 2016-0377865 A1 with optical
waveguide 230 serving as the "optical replicator," or similar to
that described in US Patent Publication US 2016-0377866 A1 with
optical waveguide 230 serving as the "optical splitter," or similar
to a combination of the configurations described in US Patent
Publications US 2016-0377865 A1 and US 2016-0377866 A1 with optical
waveguide 230 combining the functions of both the "optical
replicator" and the "optical splitter." Whether optical waveguide
230 functions more like an "optical replicator," an "optical
splitter," or a combination of an optical replicator and an optical
splitter depends on the specific implementation.
[0053] For example, optical waveguide 230 may be designed to
operate as an "optical replicator" as follows: optical waveguide
230 may be positioned and oriented to guide (e.g., via total
internal reflection) light 201 from input coupler 231 towards first
output coupler 232, where first output coupler 232 is oriented to
redirect a first portion 201a of light 201 out through free space
towards holographic combiner 260 and to guide second portion 201b
of light 201 through waveguide 230 towards second output coupler
233 (e.g., through an inner volume of optical waveguide 230 using,
e.g., total internal reflection). In order to achieve this, first
output coupler 232 may be, for example, at least partially
reflective of first portion 201a of light 201 and at least
partially transmissive of second portion 201b of light 201. Or more
generally, first output coupler 232 may be: i) partially reflective
of light 201 so as to out-couple first portion 201a of light 201
from optical waveguide 230 through free space towards holographic
combiner 260; and ii) partially transmissive of light 201 so as to
pass through second portion 201b of light 201, which then continues
to propagate (e.g., via total internal reflection) through optical
waveguide 230 to second output coupler 233, which then out-couples
at least second portion 201b of light 201 through free space
towards holographic combiner 260. In this way, a single input light
signal 201 is replicated to produce two output light signals 201a,
201b that may generally correspond to replicated instances of the
same image content.
[0054] A person of skill in the art will appreciate that this
replication process may be generalized to any number N of output
couplers. More generally, a WHUD architecture (e.g., WHUD 200) may
be extended such that the optical waveguide (e.g., 230) includes N
output couplers (e.g., 232, 233, . . . ) carried by the optical
waveguide, where N is an integer greater than 2, and wherein each
respective one of the N output couplers (e.g., 232, 233, . . . ) is
oriented to couple a respective portion (e.g., 201a, 201b, . . . )
of light (e.g., 201) from the projector (e.g., 220) out of the
optical waveguide (e.g., 230) towards holographic combiner 260,
which then directs each respective portion of light (e.g., 201a,
201b, . . . ) to a respective one of N exit pupils (e.g., 240a,
240b, . . . ) at or proximate the eye of the user.
[0055] As another example, optical waveguide 230 may be designed to
operate as an "optical splitter" as follows: optical waveguide 230
may be positioned and oriented to guide first portion 201a of light
201 from input coupler 231 directly towards first output coupler
232 without impinging on second output coupler 233 and to guide
second portion 201b of light 201 from input coupler 231 directly
towards second output coupler 233 without impinging on first output
coupler 232. In other words, optical waveguide 230 may include and
provide separate optical paths for first portion 201a of light 201
and second portion 201b of light 201. In the "optical replicator"
example described above, optical waveguide 230 may include a single
optical channel (e.g., a single conduit or rectangular waveguide
volume through which light is propagated by total internal
reflection) through which all light signals (e.g., light signal
201, first portion 201a, and second portion 201b) are propagated.
By comparison, in this "optical splitter" example, optical
waveguide 230 may include a first optical path or channel through
which first portion 201a of light 201 is guided towards first
output coupler 232 and a second optical path or channel through
which second portion 201b of light 201 is guided towards second
output coupler 233. In this case, first portion 201a of light 201
may not be guided through the second optical path or channel and
second portion 201b of light 201 may not be guided through the
first optical path or channel. In other words, light 201 from
projector 220 may be split or divided by optical waveguide 230
(either within the volume of optical waveguide 230 or by one or
more input coupler(s) 231) and routed to respective output couplers
(232, 233) along separate optical pathways and/or through separate
optical channels.
[0056] As described previously, the optical waveguides described
herein (e.g., 130, 230) may include any number N of discrete,
spatially-separated output couplers (232, 233) operable to
out-couple N respective portions (201a, 201b) of light (201) from a
projector (220) to (either directly or through intervening optics
such as holographic combiner 260) N respective exit pupils (240a,
240b) at or proximate the eye of the user. These N output couplers
may be arranged a number of different ways, including for example
in a linear row or in a two-dimensional array.
[0057] When N discrete, spatially-separated output couplers (232,
233) are arranged in a single row across a length of an optical
waveguide (230), each the N output couplers (232, 233) may be at
least partially reflective (e.g., N-1 that are partially
reflective, and one that is either partially or totally reflective)
to couple a respective portion (201a, 201b) of light (201) from the
projector (220) out of the optical waveguide (230) and direct
(either directly or through any number of intervening optics) the
respective portion (201a, 201b) of light (201) to a respective one
of the N exit pupils (240a, 240b) at or proximate the eye of the
user. Additionally, each of at least N-1 of the output couplers
(232, 233) may be partially transmissive to transmit a respective
portion (201a, 201b) of light (201) from the projector (220)
through the optical waveguide (230) towards at least one other one
of the N output couplers (232, 233). Such a configuration provides
optical replication across a row within the optical waveguide, or
an "optical waveguide replicator row." An illustrative example of
this configuration for which N=6 is provided in FIG. 3.
[0058] FIG. 3 is an illustrative diagram showing an example of
optical waveguide 300 in accordance with the present systems,
devices, and methods. Optical waveguide 300 is an optical waveguide
replicator row for which N=6. Specifically, optical waveguide 300
includes an input coupler 310 and N=6 discrete, spatially-separated
output couplers 321, 322, 323, 324, 325, and 326 arranged in a
substantially linear row across the length of optical waveguide
300. Light 301 from a projector (not shown) is received by input
coupler 310 and guided through the inner volume of optical
waveguide 300 (e.g., via total internal reflection). Light 301 is
guided (e.g., via total internal reflection) by optical waveguide
300 to first output coupler 321 which is partially reflective of
light 301 and partially transmissive of light 301. A first portion
331a of light 301 that is reflected by first output coupler 321 is
out-coupled from optical waveguide 300 towards (either directly or
via any number of intervening optics such as holographic combiner
260) a first exit pupil at or proximate the eye of the user while a
second portion 331b of light 301 that is transmitted by first
output coupler 321 is propagated (e.g., via total internal
reflection) by optical waveguide 300 to second output coupler 322.
Light 331b is guided (e.g., via total internal reflection) by
optical waveguide 300 to second output coupler 322 which is
partially reflective of light 331b and partially transmissive of
light 331b. A first portion 332a of light 331b that is reflected by
second output coupler 322 is out-coupled from optical waveguide 300
towards (either directly or via any number of intervening optics
such as holographic combiner 260) a second exit pupil at or
proximate the eye of the user while a second portion 332b of light
331b that is transmitted by second output coupler 322 is propagated
(e.g., via total internal reflection) by optical waveguide 300 to
third output coupler 323. Light 332b is guided (e.g., via total
internal reflection) by optical waveguide 300 to third output
coupler 323 which is partially reflective of light 332b and
partially transmissive of light 332b. A first portion 333a of light
332b that is reflected by third output coupler 323 is out-coupled
from optical waveguide 300 towards (either directly or via any
number of intervening optics such as holographic combiner 260) a
third exit pupil at or proximate the eye of the user while a second
portion 333b of light 332b that is transmitted by third output
coupler 323 is propagated (e.g., via total internal reflection) by
optical waveguide 300 to fourth output coupler 324. Light 333b is
guided (e.g., via total internal reflection) by optical waveguide
300 to fourth output coupler 324 which is partially reflective of
light 333b and partially transmissive of light 333b. A first
portion 334a of light 333b that is reflected by fourth output
coupler 324 is out-coupled from optical waveguide 300 towards
(either directly or via any number of intervening optics such as
holographic combiner 260) a fourth exit pupil at or proximate the
eye of the user while a second portion 334b of light 333b that is
transmitted by fourth output coupler 324 is propagated (e.g., via
total internal reflection) by optical waveguide 300 to fifth output
coupler 325. Light 334b is guided (e.g., via total internal
reflection) by optical waveguide 300 to fifth output coupler 325
which is partially reflective of light 334b and partially
transmissive of light 334b. A first portion 335a of light 334b that
is reflected by fifth output coupler 325 is out-coupled from
optical waveguide 300 towards (either directly or via any number of
intervening optics such as holographic combiner 260) a fifth exit
pupil at or proximate the eye of the user while a second portion
335b of light 334b that is transmitted by fifth output coupler 325
is propagated (e.g., via total internal reflection) by optical
waveguide 300 to sixth output coupler 326. Light 335b is guided
(e.g., via total internal reflection) by optical waveguide 300 to
sixth output coupler 326 which is reflective (e.g., partially or
fully reflective) of light 335b. Sixth output coupler 326 reflects
and outcouples at least a portion 336a of light 335b towards
(either directly or via any number of intervening optics such as
holographic combiner 260) a sixth exit pupil at or proximate the
eye of the user.
[0059] FIG. 3 shows an example of an optical waveguide configured
to operate as an optical waveguide replicator row (with N=6
discrete, spatially-separated output couplers) as an eyebox
expansion optic in a WHUD. For example, optical waveguide 300 may
replace optical waveguide 130 from FIG. 1 directly in the user's
field of view or may replace optical waveguide 230 from FIG. 2 as a
replication input to holographic combiner 230. An advantage of
having N discrete, spatially-separated output couplers in an
optical waveguide replicator row as opposed to a single continuous
output coupler is that each discrete, spatially-separated output
coupler may be deliberately positioned and/or designed to output
light in a specific and independent (e.g., unique) way (e.g., with
a particular optical power or other optical function, directed
towards a particular position, at a particular position relative to
other output couplers such that outcoupling is partially based on
output coupler position rather than solely total internal
reflection angle, to outcouple only a specific wavelength, and so
on). However, as previously described, the present systems,
devices, and methods may be extended to include optical waveguides
have two-dimensional arrays of output couplers.
[0060] Generally, the N output couplers may be arranged in an array
having P>1 rows and Q>1 columns. In such implementations, the
optical waveguide may include P optical paths or channels and be
positioned and oriented to guide a respective portion of light from
the projector along or into and through each respective one of the
P optical pathways or channels. Q output couplers in each
respective one of the P optical pathways or channels may be
arranged in a single row across a length of the optical pathway or
channel. Each of the Q output couplers in each of the P optical
channels may be at least partially reflective (e.g., Q-1 that are
partially reflective and one that is fully reflective) to couple a
respective portion of light from the projector out of the optical
waveguide and direct the respective portion of light (either
directly or via any number of intervening optics) to a respective
one of the N exit pupils at or proximate the eye of the user.
Additionally, each of at least Q-1 of the Q output couplers in each
of the P optical channels may be partially transmissive to transmit
a respective portion of light from the projector through the
optical waveguide towards at least one other one of the Q output
couplers in the optical pathway or channel.
[0061] FIG. 4 is an illustrative diagram showing an example of
optical waveguide 400 in accordance with the present systems,
devices, and methods. Optical waveguide 400 comprises N=8 discrete,
spatially-separated output couplers arranged in an array of P=2
rows and Q=4 columns. Specifically, optical waveguide 300 includes
an input coupler 410, a first "topmost" row of 4 discrete,
spatially-separated output couplers 421, 422, 423, and 424, and a
second "bottommost" row of discrete, spatially-separated output
couplers 441, 442, 443, and 444.
[0062] Light 401 from a projector (not shown) is received by input
coupler 410. A first portion 401a of light 401 is routed towards
the topmost row of output couplers 421, 422, 423, and 424 and a
second portion 401b of light 401 is routed towards the bottommost
row of output couplers 441, 442, 443, and 444. This initial routing
may be accomplished in a variety of different ways. As a first
example, input coupler 410 may include beam splitters and/or
partial reflectors (or custom optics such as gratings or holograms
that provide beam splitting and/or partial reflection
functionality) to essentially replicate light 401 and produce two
copies 401a and 401b, each routed towards a respective row of
output couplers. In this case, optical waveguide 400 provides a
complete optical replication array with N=8 replicated copies of
light 401 being output. Alternatively, as a second example, input
coupler 410 may provide an optical splitter/divider functionality
by routing a first range of light signals 401 (e.g., a first
portion of the total scan range of a raster scanning projector)
towards topmost row of output couplers 421, 422, 423, and 424 and
routing a second range of light signals 401 (e.g., a second portion
of the total scan range of a raster scanning projector) towards
bottommost row of output couplers 441, 442, 443, and 444.
Specifically, if the projector source of light 401 is a scanning
laser projector that sweeps over a range of scan angles, input
coupler 410 may receive light 401 over the entire sweep of scan
angles from the projector and cause a first portion (e.g., half) of
said sweep to route towards topmost row of output couplers 421,
422, 423, and 424 and a second portion (e.g., half) of said sweep
towards bottommost row of output couplers 441, 442, 443, and 444.
In this way, input coupler 410 essentially splits or divides light
signals 401 from a projector into two ranges in a similar way to
the optical splitter described in US 2016-0377866 A1.
[0063] Once light 401 has been replicated, split, or divided into
P=2 portions, a first portion 401a is then replicated Q=4 times by
output couplers 421, 422, 423, and 424 and a second portion 401b is
replicated Q=4 times by output couplers 441, 442, 443, and 444.
That is, output couplers 421, 422, 423, and 424 behave as a first
optical waveguide replicator row similar to optical waveguide 300
from FIG. 3 and output couplers 441, 442, 443, and 444 behave as a
second optical waveguide replicator row similar to optical
waveguide 300 from FIG. 3.
[0064] Light 401a is guided (e.g., via total internal reflection)
by optical waveguide 400 to first output coupler 421 which is
partially reflective of light 401a and partially transmissive of
light 401a. A first portion 431a of light 401a that is reflected by
first output coupler 421 is out-coupled from optical waveguide 400
towards (either directly or via any number of intervening optics
such as holographic combiner 260) a first exit pupil at or
proximate the eye of the user while a second portion 431b of light
401a that is transmitted by first output coupler 421 is propagated
(e.g., via total internal reflection) by optical waveguide 400 to
second output coupler 422. Light 431b is guided (e.g., via total
internal reflection) by optical waveguide 400 to second output
coupler 422 which is partially reflective of light 431b and
partially transmissive of light 431b. A first portion 432a of light
431b that is reflected by second output coupler 422 is out-coupled
from optical waveguide 400 towards (either directly or via any
number of intervening optics such as holographic combiner 260) a
second exit pupil at or proximate the eye of the user while a
second portion 432b of light 431b that is transmitted by second
output coupler 422 is propagated (e.g., via total internal
reflection) by optical waveguide 400 to third output coupler 423.
Light 432b is guided (e.g., via total internal reflection) by
optical waveguide 400 to third output coupler 423 which is
partially reflective of light 432b and partially transmissive of
light 432b. A first portion 433a of light 432b that is reflected by
third output coupler 423 is out-coupled from optical waveguide 400
towards (either directly or via any number of intervening optics
such as holographic combiner 260) a third exit pupil at or
proximate the eye of the user while a second portion 433b of light
432b that is transmitted by third output coupler 423 is propagated
(e.g., via total internal reflection) by optical waveguide 400 to
fourth output coupler 424. Light 433b is guided (e.g., via total
internal reflection) by optical waveguide 400 to fourth output
coupler 424 which is at least partially reflective (may be fully
reflective) of light 433b. At least a first portion 434a of light
433b that is reflected by fourth output coupler 424 is out-coupled
from optical waveguide 400 towards (either directly or via any
number of intervening optics such as holographic combiner 260) a
fourth exit pupil at or proximate the eye of the user.
[0065] Light 401b is guided (e.g., via total internal reflection)
by optical waveguide 400 to fifth output coupler 441 which is
partially reflective of light 401b and partially transmissive of
light 401b. A first portion 451a of light 401b that is reflected by
fifth output coupler 441 is out-coupled from optical waveguide 400
towards (either directly or via any number of intervening optics
such as holographic combiner 260) a fifth exit pupil at or
proximate the eye of the user while a second portion 451b of light
401b that is transmitted by fifth output coupler 441 is propagated
(e.g., via total internal reflection) by optical waveguide 400 to
sixth output coupler 442. Light 451b is guided (e.g., via total
internal reflection) by optical waveguide 400 to sixth output
coupler 442 which is partially reflective of light 451b and
partially transmissive of light 451b. A first portion 452a of light
451b that is reflected by sixth output coupler 442 is out-coupled
from optical waveguide 400 towards (either directly or via any
number of intervening optics such as holographic combiner 260) a
sixth exit pupil at or proximate the eye of the user while a second
portion 452b of light 451b that is transmitted by sixth output
coupler 442 is propagated (e.g., via total internal reflection) by
optical waveguide 400 to seventh output coupler 443. Light 452b is
guided (e.g., via total internal reflection) by optical waveguide
400 to seventh output coupler 443 which is partially reflective of
light 452b and partially transmissive of light 452b. A first
portion 453a of light 452b that is reflected by seventh output
coupler 443 is out-coupled from optical waveguide 400 towards
(either directly or via any number of intervening optics such as
holographic combiner 260) a seventh exit pupil at or proximate the
eye of the user while a second portion 453b of light 452b that is
transmitted by seventh output coupler 443 is propagated (e.g., via
total internal reflection) by optical waveguide 400 to eighth
output coupler 444. Light 453b is guided (e.g., via total internal
reflection) by optical waveguide 400 to eighth output coupler 444
which is at least partially reflective (may be fully reflective) of
light 453b. At least a first portion 454a of light 453b that is
reflected by eighth output coupler 444 is out-coupled from optical
waveguide 400 towards (either directly or via any number of
intervening optics such as holographic combiner 260) an eighth exit
pupil at or proximate the eye of the user.
[0066] As described previously, light that is "out-coupled towards
an exit pupil" may be out-coupled to converge directly towards an
exit pupil (e.g., with no intervening optics, where the output
coupler itself may provide the converge function to the light, as
in, for example, the case where the optical waveguide itself is
carried by an eyeglass lens such as in FIG. 1), or light that is
"out-coupled towards an exit pupil" may be out-coupled towards a
holographic combiner that receives the light and redirects it
towards the corresponding exit pupil (as in, for example, the case
where the optical waveguide itself is carried in an arm or temple
of a support structure as in FIG. 2). In the latter configuration,
the holographic combiner may impart the convergence function to the
light upon redirection.
[0067] A person of skill in the art will appreciate that the input
couplers and output couplers described throughout this
specification and the appended claims may come in a variety of
different forms, including without limitation: optical gratings,
diffraction gratins, volume gratings, surface relief gratings,
holograms, volume holograms, surface relief holograms, and/or any
combination of the foregoing.
[0068] In some implementations, a single input coupler may be used
to split/divide/replicate/direct light through an optical waveguide
to any number of output couplers. In other implementations,
multiple discrete, spatially-separated input couplers may be
employed. For example, input coupler 410 in optical waveguide 400
may comprise two separate input couplers with a first input coupler
operative to direct light 401a towards output couplers 421, 422,
423, and 424 and a second input coupler operative to direct light
401b towards output couplers 441, 442, 443, and 444.
[0069] A person of skill in the art will appreciate that the
present systems, devices, and methods may be applied or otherwise
incorporated into WHUD architectures that employ one or more
transparent combiner(s) other than a holographic combiner. For
example, in some implementations the holographic combiner described
herein may be replaced by a non-holographic device that
accomplishes substantially the same general function(s), such as
prismatic film, a film that carries a microlens array, and/or a
waveguide structure. Such non-holographic implementations may or
may not employ additional optics. Unless the specific context
requires otherwise, a person of skill in the art will appreciate
that references to a "holographic combiner" throughout the present
systems, devices, and methods are generic to other transparent
combiners (combined with other optics, as necessary) that may be
applied or adapted for application to accomplish the same general
function(s) associated with the holographic combiners described
herein.
[0070] A person of skill in the art will appreciate that the
various embodiments for eyebox expansion by exit pupil replication
described herein may be applied in non-WHUD applications. For
example, the present systems, devices, and methods may be applied
in non-wearable heads-up displays and/or in other projection
displays, including virtual reality displays, in which the
holographic combiner need not necessarily be transparent.
[0071] In binocular implementations (i.e., implementations in which
display content is projected into both eyes of the user), the total
field of view may be increased by deliberately projecting a
different field of view to each eye of the user. The two fields of
view may overlap, so that both eyes see content at the center of
the field of view while the left eye sees more content at the left
of the field of view and the right eye sees more content at the
right of the field of view.
[0072] In some implementations that employ multiple exit pupils,
all exit pupils may optionally be active at all times.
Alternatively, implementations that also employ eye-tracking, may
activate only the exit pupil that corresponds to where the user is
looking (based on eye-tracking) while one or more exit pupil(s)
that is/are outside of the user's field of view may be
deactivated.
[0073] Eyebox expansion may advantageously enable a user to see
displayed content while gazing in a wide range of directions.
Furthermore, eyebox expansion may also enable a wider variety of
users having a wider range of eye arrangements to adequately see
displayed content via a given WHUD. Anatomical details such as
interpupillary distance, eye shape, relative eye positions, and so
on can all vary from user to user. The various eyebox expansion
methods described herein may be used to render a WHUD more robust
over (and therefore more usable by) a wide variety of users having
anatomical differences. In order to even further accommodate
physical variations from user to user, the various WHUDs described
herein may include one or more mechanical structure(s) that enable
the user to controllably adjust the physical position and/or
alignment of one or more exit pupil(s) relative to their own
eye(s). Such mechanical structures may include one or more
hinge(s), dial(s), flexure(s), tongue and groove or other
slidably-coupled components, and the like. Alternatively, the
approaches taught herein may advantageously avoid the need for
inclusion of such additional mechanical structures, allowing a
smaller package and less weight than might otherwise be
obtainable.
[0074] In some implementations, one or more optical fiber(s) may be
used to guide light signals along some of the paths illustrated
herein.
[0075] When used herein in relation to a specified quantity, the
term "about" generally means ".+-.10%" unless the specific context
requires otherwise.
[0076] Throughout this specification and the various exemplary
embodiments described herein, reference is often made to a
"projector." A person of skill in the art will appreciate that in
some implementations of the present systems, devices, and methods a
projector may include or be replaced by a microdisplay.
[0077] The WHUDs described herein may include one or more sensor(s)
(e.g., microphone, camera, thermometer, compass, altimeter, and/or
others) for collecting data from the user's environment. For
example, one or more camera(s) may be used to provide feedback to
the processor of the WHUD and influence where on the display(s) any
given image should be displayed.
[0078] The WHUDs described herein may include one or more on-board
power sources (e.g., one or more battery(ies)), a wireless
transceiver for sending/receiving wireless communications, and/or a
tethered connector port for coupling to a computer and/or charging
the one or more on-board power source(s).
[0079] Throughout this specification and the appended claims the
term "communicative" as in "communicative pathway," "communicative
coupling," and in variants such as "communicatively coupled," is
generally used to refer to any engineered arrangement for
transferring and/or exchanging information. Exemplary communicative
pathways include, but are not limited to, electrically conductive
pathways (e.g., electrically conductive wires, electrically
conductive traces), magnetic pathways (e.g., magnetic media),
and/or optical pathways (e.g., optical fiber), and exemplary
communicative couplings include, but are not limited to, electrical
couplings, magnetic couplings, and/or optical couplings.
[0080] Throughout this specification and the appended claims,
infinitive verb forms are often used. Examples include, without
limitation: "to detect," "to provide," "to transmit," "to
communicate," "to process," "to route," and the like. Unless the
specific context requires otherwise, such infinitive verb forms are
used in an open, inclusive sense, that is as "to, at least,
detect," to, at least, provide," "to, at least, transmit," and so
on.
[0081] The above description of illustrated embodiments, including
what is described in the Abstract, is not intended to be exhaustive
or to limit the embodiments to the precise forms disclosed.
Although specific embodiments of and examples are described herein
for illustrative purposes, various equivalent modifications can be
made without departing from the spirit and scope of the disclosure,
as will be recognized by those skilled in the relevant art. The
teachings provided herein of the various embodiments can be applied
to other portable and/or wearable electronic devices, not
necessarily the exemplary wearable electronic devices generally
described above.
[0082] For instance, the foregoing detailed description has set
forth various embodiments of the devices and/or processes via the
use of block diagrams, schematics, and examples. Insofar as such
block diagrams, schematics, and examples contain one or more
functions and/or operations, it will be understood by those skilled
in the art that each function and/or operation within such block
diagrams, flowcharts, or examples can be implemented, individually
and/or collectively, by a wide range of hardware, software,
firmware, or virtually any combination thereof. In one embodiment,
the present subject matter may be implemented via Application
Specific Integrated Circuits (ASICs). However, those skilled in the
art will recognize that the embodiments disclosed herein, in whole
or in part, can be equivalently implemented in standard integrated
circuits, as one or more computer programs executed by one or more
computers (e.g., as one or more programs running on one or more
computer systems), as one or more programs executed by on one or
more controllers (e.g., microcontrollers) as one or more programs
executed by one or more processors (e.g., microprocessors, central
processing units, graphical processing units), as firmware, or as
virtually any combination thereof, and that designing the circuitry
and/or writing the code for the software and or firmware would be
well within the skill of one of ordinary skill in the art in light
of the teachings of this disclosure.
[0083] When logic is implemented as software and stored in memory,
logic or information can be stored on any processor-readable medium
for use by or in connection with any processor-related system or
method. In the context of this disclosure, a memory is a
processor-readable medium that is an electronic, magnetic, optical,
or other physical device or means that contains or stores a
computer and/or processor program. Logic and/or the information can
be embodied in any processor-readable medium for use by or in
connection with an instruction execution system, apparatus, or
device, such as a computer-based system, processor-containing
system, or other system that can fetch the instructions from the
instruction execution system, apparatus, or device and execute the
instructions associated with logic and/or information.
[0084] In the context of this specification, a "non-transitory
processor-readable medium" can be any element that can store the
program associated with logic and/or information for use by or in
connection with the instruction execution system, apparatus, and/or
device. The processor-readable medium can be, for example, but is
not limited to, an electronic, magnetic, optical, electromagnetic,
infrared, or semiconductor system, apparatus or device. More
specific examples (a non-exhaustive list) of the computer readable
medium would include the following: a portable computer diskette
(magnetic, compact flash card, secure digital, or the like), a
random access memory (RAM), a read-only memory (ROM), an erasable
programmable read-only memory (EPROM, EEPROM, or Flash memory), a
portable compact disc read-only memory (CDROM), digital tape, and
other non-transitory media.
[0085] The various embodiments described above can be combined to
provide further embodiments. To the extent that they are not
inconsistent with the specific teachings and definitions herein,
all of the U.S. patents, U.S. patent application publications, U.S.
patent applications, foreign patents, foreign patent applications
and non-patent publications referred to in this specification
and/or listed in the Application Data Sheet which are owned by
Thalmic Labs Inc., including but not limited to: U.S. Provisional
Patent Application Ser. No. 62/564,858, U.S. Provisional Patent
Application Ser. No. 62/482,062 (now U.S. patent application Ser.
Nos. 15/946,549, 15/946,557, 15/946,562, 15/946,565, and
15/946,569), US Patent Application Publication No. US 2016-0377865
A1, US Patent Application Publication No. US 2016-0377866 A1, US
Patent Application Publication No. US 2016-0238845 A1, US Patent
Application Publication No. US 2017-0212349 A1, US Patent
Application Publication No. US 2016-0327797 A1, US Patent
Application Publication No. US 2016-0327796 A1, US Patent
Application Publication No. US 2016-0349516 A1, US Patent
Application Publication No. US 2017-0068095 A1, US Patent
Application Publication No. US 2017-0212290 A1, US Patent
Application Publication No. US 2017-0219829 A1, U.S. Provisional
Patent Application Ser. No. 62/487,303, and U.S. Provisional Patent
Application Ser. No. 62/534,099, are incorporated herein by
reference, in their entirety. Aspects of the embodiments can be
modified, if necessary, to employ systems, circuits and concepts of
the various patents, applications and publications to provide yet
further embodiments.
[0086] These and other changes can be made to the embodiments in
light of the above-detailed description. In general, in the
following claims, the terms used should not be construed to limit
the claims to the specific embodiments disclosed in the
specification and the claims, but should be construed to include
all possible embodiments along with the full scope of equivalents
to which such claims are entitled. Accordingly, the claims are not
limited by the disclosure.
* * * * *