U.S. patent application number 16/018986 was filed with the patent office on 2018-10-18 for systems, devices, and methods for eyebox expansion in wearable heads-up displays.
The applicant listed for this patent is THALMIC LABS INC.. Invention is credited to Stefan Alexander, Matthew Bailey, Lloyd Frederick Holland, Vance R. Morrison.
Application Number | 20180299680 16/018986 |
Document ID | / |
Family ID | 56621075 |
Filed Date | 2018-10-18 |
United States Patent
Application |
20180299680 |
Kind Code |
A1 |
Alexander; Stefan ; et
al. |
October 18, 2018 |
SYSTEMS, DEVICES, AND METHODS FOR EYEBOX EXPANSION IN WEARABLE
HEADS-UP DISPLAYS
Abstract
Systems, devices, and methods for eyebox expansion by exit pupil
replication in scanning laser-based wearable heads-up displays
("WHUDs") are described. The WHUDs described herein each include a
scanning laser projector ("SLP"), a holographic combiner, and an
optical replicator positioned in the optical path therebetween. For
each light signal generated by the SLP, the optical replicator
receives the light signal and redirects each one of N>1
instances of the light signal towards the holographic combiner
effectively from a respective one of N spatially-separated virtual
positions for the SLP. The holographic combiner converges each one
of the N instances of the light signal to a respective one of N
spatially-separated exit pupils at the eye of the user. In this
way, multiple instances of the exit pupil are distributed over the
area of the eye and the eyebox of the WHUD is expanded.
Inventors: |
Alexander; Stefan; (Elmira,
CA) ; Bailey; Matthew; (Kitchener, CA) ;
Morrison; Vance R.; (Kitchener, CA) ; Holland; Lloyd
Frederick; (Kitchener, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
THALMIC LABS INC. |
Kitchener |
|
CA |
|
|
Family ID: |
56621075 |
Appl. No.: |
16/018986 |
Filed: |
June 26, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15046234 |
Feb 17, 2016 |
10031338 |
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16018986 |
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62117316 |
Feb 17, 2015 |
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62156736 |
May 4, 2015 |
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62242844 |
Oct 16, 2015 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02B 26/10 20130101;
G03H 1/2645 20130101; G02B 27/12 20130101; G02B 27/0172 20130101;
G02B 2027/0112 20130101; G02B 27/0081 20130101; G02B 27/017
20130101; G06F 3/011 20130101; G03H 1/265 20130101; G02B 2027/0125
20130101; G02B 2027/0123 20130101; G06F 1/163 20130101; G02B
2027/0178 20130101; G09G 3/001 20130101; G02B 2027/0174 20130101;
G03H 2001/266 20130101; G06F 3/013 20130101 |
International
Class: |
G02B 27/01 20060101
G02B027/01; G09G 3/00 20060101 G09G003/00; G02B 26/10 20060101
G02B026/10; G06F 3/01 20060101 G06F003/01; G06F 1/16 20060101
G06F001/16; G02B 27/00 20060101 G02B027/00; G02B 27/12 20060101
G02B027/12; G03H 1/26 20060101 G03H001/26 |
Claims
1. A method of operating a wearable heads-up display, the wearable
heads-up display including a scanning laser projector, an optical
replicator, and a holographic combiner positioned within a field of
view of an eye of a user when the wearable heads-up display is worn
on a head of the user, the method comprising: generating a first
light signal by the scanning laser projector; redirecting
respective ones of N instances of the first light signal towards
the holographic combiner by the optical replicator, where N is an
integer greater than 1; and redirecting each instance of the first
light signal that is received from the optical replicator towards
the eye of the user by the holographic combiner.
2. The method of claim 1, further comprising: receiving the first
light signal from the scanning laser projector by the optical
replicator; and replicating the first light signal into the N
instances of the first light signal by the optical replicator.
3. The method of claim 1 wherein redirecting each instance of the
first light signal that is received from the optical replicator
towards the eye of the user by the holographic combiner includes
redirecting each instance of the first light signal that is
received from the optical replicator spatially in parallel with one
another towards respective regions of the eye of the user by the
holographic combiner.
4. The method of claim 1 wherein redirecting respective ones of N
instances of the first light signal towards the holographic
combiner by the optical replicator includes redirecting respective
ones of N instances of the first light signal towards the
holographic combiner by the optical replicator effectively from
respective ones of N spatially-separated virtual positions for the
scanning laser projector.
5. The method of claim 1 wherein redirecting each instance of the
first light signal that is received from the optical replicator
towards the eye of the user by the holographic combiner includes
converging each instance of the first light signal that is received
from the optical replicator to a respective exit pupil at or
proximate the eye of the user by the holographic combiner.
6. The method of claim 5 wherein the holographic combiner includes
at least two multiplexed holograms, and wherein converging each
instance of the first light signal that is received from the
optical replicator to a respective exit pupil at or proximate the
eye of the user by the holographic combiner includes converging
each instance of the first light signal that is received from the
optical replicator to a respective exit pupil at or proximate the
eye of the user by a respective multiplexed hologram.
7. The method of claim 6 wherein: the scanning laser projector
includes a red laser diode, a green laser diode, and a blue laser
diode; the first light signal generated by the scanning laser
projector includes a red component, a green component, and a blue
component; and the holographic combiner includes a
wavelength-multiplexed holographic combiner that includes at least
one red hologram, at least one green hologram, and at least one
blue hologram, and wherein converging each instance of the first
light signal that is received from the optical replicator to a
respective exit pupil at or proximate the eye of the user by a
respective multiplexed hologram includes: converging a respective
red component of each instance of the first light signal that is
received from the optical replicator to a respective exit pupil at
or proximate the eye of the user by the at least one red hologram;
converging a respective green component of each instance of the
first light signal that is received from the optical replicator to
a respective exit pupil at or proximate the eye of the user by the
at least one green hologram; and converging a respective blue
component of each instance of the first light signal that is
received from the optical replicator to a respective exit pupil at
or proximate the eye of the user by the at least one blue
hologram.
8. The method of claim 7 wherein the holographic combiner includes
a wavelength-multiplexed and angle-multiplexed holographic combiner
that includes at least two angle-multiplexed red holograms, at
least two angle-multiplexed green holograms, and at least two
angle-multiplexed blue holograms, and wherein: converging a
respective red component of each instance of the first light signal
that is received from the optical replicator to a respective exit
pupil at or proximate the eye of the user by the at least one red
hologram includes converging a respective red component of each
instance of the first light signal that is received from the
optical replicator to a respective exit pupil at or proximate the
eye of the user by a respective angle-multiplexed red hologram;
converging a respective green component of each instance of the
first light signal that is received from the optical replicator to
a respective exit pupil at or proximate the eye of the user by the
at least one green hologram includes converging a respective green
component of each instance of the first light signal that is
received from the optical replicator to a respective exit pupil at
or proximate the eye of the user by a respective angle-multiplexed
green hologram; and converging a respective blue component of each
instance of the first light signal that is received from the
optical replicator to a respective exit pupil at or proximate the
eye of the user by the at least one blue hologram includes
converging a respective blue component of each instance of the
first light signal that is received from the optical replicator to
a respective exit pupil at or proximate the eye of the user by a
respective angle-multiplexed blue hologram.
9. The method of claim 1, further comprising: generating at least a
second light signal by the scanning laser projector; redirecting
respective ones of N instances of the at least a second light
signal towards the holographic combiner by the optical replicator;
and converging each instance of the at least a second light signal
that is received from the optical replicator to a respective exit
pupil at or proximate the eye of the user by the holographic
combiner.
10. The method of claim 1, further comprising: generating light
signals corresponding to a sweep of a total scan range .theta. by
the scanning laser projector; receiving the light signals
corresponding to the total scan range .theta. of the scanning laser
projector by the optical replicator; redirecting respective ones of
N instances of the total scan range .theta. of the scanning laser
projector towards the holographic combiner by the optical
replicator; and converging each instance of the total scan range
.theta. of the scanning laser projector that is received from the
optical replicator to a respective exit pupil at or proximate the
eye of the user by the holographic combiner.
11. The method of claim 1 wherein the first light signal includes
an image comprising at least two pixels and redirecting respective
ones of N instances of the first light signal towards the
holographic combiner by the optical replicator includes redirecting
N respective instances of a same image towards the holographic
combiner by the optical replicator.
12. The method of claim 1 wherein redirecting respective ones of N
instances of the first light signal towards the holographic
combiner by the optical replicator includes redirecting N
respective instances of a same pixel in a different instance of a
same image towards the holographic combiner by the optical
replicator.
Description
BACKGROUND
Technical Field
[0001] The present systems, devices, and methods generally relate
to scanning laser-based display technologies and particularly
relate to expanding the eyebox of a scanning laser-based wearable
heads-up display.
Description of the Related Art
[0002] Wearable Heads-Up Displays
[0003] 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.
[0004] 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.
[0005] A challenge in the design of wearable heads-up displays is
to minimize the bulk of the face-worn apparatus while 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.
[0006] Eyebox
[0007] 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.
[0008] 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.
[0009] 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
[0010] A wearable heads-up display may be summarized as including:
a support structure that in use is worn on a head of a user; a
scanning laser projector carried by the support structure; a
holographic combiner carried by the support structure, wherein the
holographic combiner is positioned within a field of view of an eye
of the user when the support structure is worn on the head of the
user; and an optical replicator carried by the support structure
and positioned in an optical path between the scanning laser
projector and the holographic combiner, the optical replicator
comprising at least one optical element arranged to receive a light
signal generated by the scanning laser projector and redirect
respective ones of N instances of the light signal towards the
holographic combiner, where N is an integer greater than 1, and
wherein the holographic combiner comprises at least one hologram
positioned and oriented to redirect each one of the N instances of
the light signal towards the eye of the user. The at least one
hologram of the holographic combiner may redirect the N instances
of the light signal all spatially in parallel with one another
towards respective regions of the eye of the user. At least one
optical element of the optical replicator may be arranged to
redirect respective ones of the N instances of the light signal
towards the holographic combiner effectively from respective ones
of N spatially-separated virtual positions for the scanning laser
projector.
[0011] The support structure may have a general shape and
appearance of an eyeglasses frame. The wearable heads-up display
may further include a prescription eyeglass lens, wherein the
holographic combiner is carried by the prescription eyeglass
lens.
[0012] The at least one hologram of the holographic combiner may
converge each one of the N instances of the light signal to a
respective one of N exit pupils at or proximate the eye of the
user. The holographic combiner may include at least N multiplexed
holograms, and each one of the at least N multiplexed holograms may
converge a respective one of the N instances of the light signal to
a respective one of the N exit pupils at or proximate the eye of
the user. The scanning laser projector may include a red laser
diode, a green laser diode, and a blue laser diode, and the
holographic combiner may include a wavelength-multiplexed
holographic combiner that includes at least one red hologram, at
least one green hologram, and at least one blue hologram. In this
case, the at least one red hologram may converge a respective red
component of each one of the N instances of the light signal to a
respective one of the N exit pupils at or proximate the eye of the
user, the at least one green hologram may converge a respective
green component of each one of the N instances of the light signal
to a respective one of the N exit pupils at or proximate the eye of
the user, and the at least one blue hologram may converge a
respective blue component of each one of the N instances of the
light signal to a respective one of the N exit pupils at or
proximate the eye of the user. The holographic combiner may include
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 each one of the at least N
angle-multiplexed red holograms may converge a respective red
component of each one of the N instances of the light signal to a
respective one of the N exit pupils at or proximate the eye of the
user, each one of the at least N angle-multiplexed green holograms
may converge a respective green component of each one of the N
instances of the light signal to a respective one of the N exit
pupils at or proximate the eye of the user, and each one of the at
least N angle-multiplexed blue holograms may converge a respective
blue component of each one of the N instances of the light signal
to a respective one of the N exit pupils at or proximate the eye of
the user.
[0013] The optical path between the scanning laser projector and
the holographic combiner may include a total scan range .theta. of
the scanning laser projector, and at least one optical element of
the optical replicator may be arranged to receive all light signals
corresponding to a sweep of the total scan range .theta. by the
scanning laser projector and redirect respective ones of N
instances of all light signals corresponding to the sweep of the
total scan range .theta. of the scanning laser projector towards
the holographic combiner.
[0014] The light signal may include an image comprising at least
two pixels, and each one of the N instances of the light signal may
include a respective instance of the image. Alternatively, each one
of the N instances of the light signal includes a respective
instance of a same pixel in a different instance of a same
image.
[0015] The wearable heads-up display may further include: an eye
tracker carried by the support structure, positioned and oriented
to determine a gaze direction of the eye of the user; and at least
one controllable shutter carried by the support structure and
positioned in at least one optical path between the optical
replicator and the holographic combiner, the at least one
controllable shutter controllable to selectively block all but at
least one of the N instances of the light signal redirected towards
the holographic combiner by the optical replicator, the at least
one of the N instances of the light signal that is not blocked by
the at least one controllable shutter corresponding to the at least
one of the N instances of the light signal that, when redirected by
the holographic combiner, is redirected by the holographic combiner
towards a region of the eye of the user that contains a pupil of
the eye of the user based on the gaze direction of the eye of the
user determined by the eye tracker.
[0016] A method of operating a wearable heads-up display, the
wearable heads-up display including a scanning laser projector, an
optical replicator, and a holographic combiner positioned within a
field of view of an eye of a user when the wearable heads-up
display is worn on a head of the user, may be summarized as
including: generating a first light signal by the scanning laser
projector; redirecting respective ones of N instances of the first
light signal towards the holographic combiner by the optical
replicator, where N is an integer greater than 1; and redirecting
each instance of the first light signal that is received from the
optical replicator towards the eye of the user by the holographic
combiner. The method may further include: receiving the first light
signal from the scanning laser projector by the optical replicator;
and replicating the first light signal into the N instances of the
first light signal by the optical replicator. Redirecting each
instance of the first light signal that is received from the
optical replicator towards the eye of the user by the holographic
combiner may include redirecting each instance of the first light
signal that is received from the optical replicator spatially in
parallel with one another towards respective regions of the eye of
the user by the holographic combiner. Redirecting respective ones
of N instances of the first light signal towards the holographic
combiner by the optical replicator may include redirecting
respective ones of N instances of the first light signal towards
the holographic combiner by the optical replicator effectively from
respective ones of N spatially-separated virtual positions for the
scanning laser projector.
[0017] Redirecting each instance of the first light signal that is
received from the optical replicator towards the eye of the user by
the holographic combiner may include converging each instance of
the first light signal that is received from the optical replicator
to a respective exit pupil at or proximate the eye of the user by
the holographic combiner. The holographic combiner may include at
least two multiplexed holograms, and converging each instance of
the first light signal that is received from the optical replicator
to a respective exit pupil at or proximate the eye of the user by
the holographic combiner may include converging each instance of
the first light signal that is received from the optical replicator
to a respective exit pupil at or proximate the eye of the user by a
respective multiplexed hologram.
[0018] The scanning laser projector may include a red laser diode,
a green laser diode, and a blue laser diode; the first light signal
generated by the scanning laser projector may include a red
component, a green component, and a blue component; and the
holographic combiner may include a wavelength-multiplexed
holographic combiner that includes at least one red hologram, at
least one green hologram, and at least one blue hologram. In this
case, converging each instance of the first light signal that is
received from the optical replicator to a respective exit pupil at
or proximate the eye of the user by a respective multiplexed
hologram may include: converging a respective red component of each
instance of the first light signal that is received from the
optical replicator to a respective exit pupil at or proximate the
eye of the user by the at least one red hologram; converging a
respective green component of each instance of the first light
signal that is received from the optical replicator to a respective
exit pupil at or proximate the eye of the user by the at least one
green hologram; and converging a respective blue component of each
instance of the first light signal that is received from the
optical replicator to a respective exit pupil at or proximate the
eye of the user by the at least one blue hologram. The holographic
combiner may include a wavelength-multiplexed and angle-multiplexed
holographic combiner that includes at least two angle-multiplexed
red holograms, at least two angle-multiplexed green holograms, and
at least two angle-multiplexed blue holograms. In this case,
converging a respective red component of each instance of the first
light signal that is received from the optical replicator to a
respective exit pupil at or proximate the eye of the user by the at
least one red hologram may include converging a respective red
component of each instance of the first light signal that is
received from the optical replicator to a respective exit pupil at
or proximate the eye of the user by a respective angle-multiplexed
red hologram; converging a respective green component of each
instance of the first light signal that is received from the
optical replicator to a respective exit pupil at or proximate the
eye of the user by the at least one green hologram may include
converging a respective green component of each instance of the
first light signal that is received from the optical replicator to
a respective exit pupil at or proximate the eye of the user by a
respective angle-multiplexed green hologram; and converging a
respective blue component of each instance of the first light
signal that is received from the optical replicator to a respective
exit pupil at or proximate the eye of the user by the at least one
blue hologram may include converging a respective blue component of
each instance of the first light signal that is received from the
optical replicator to a respective exit pupil at or proximate the
eye of the user by a respective angle-multiplexed blue
hologram.
[0019] The method may further include: generating at least a second
light signal by the scanning laser projector; redirecting
respective ones of N instances of the at least a second light
signal towards the holographic combiner by the optical replicator;
and converging each instance of the at least a second light signal
that is received from the optical replicator to a respective exit
pupil at or proximate the eye of the user by the holographic
combiner.
[0020] The method may further include: generating light signals
corresponding to a sweep of a total scan range .theta. by the
scanning laser projector; receiving the light signals corresponding
to the total scan range .theta. of the scanning laser projector by
the optical replicator; redirecting respective ones of N instances
of the total scan range .theta. of the scanning laser projector
towards the holographic combiner by the optical replicator; and
converging each instance of the total scan range .theta. of the
scanning laser projector that is received from the optical
replicator to a respective exit pupil at or proximate the eye of
the user by the holographic combiner.
[0021] The wearable heads-up display may further include an eye
tracker and at least one controllable shutter and the method
further include: determining a gaze direction of the eye of the
user by the eye tracker; and selectively blocking all but at least
one of the N instances of the light signal redirected towards the
holographic combiner from the optical replicator by the at least
one controllable shutter. In this case, redirecting each instance
of the first light signal that is received from the optical
replicator towards the eye of the user by the holographic combiner
may include, for the at least one of the N instances of the first
light signal that is not blocked by the at least one controllable
shutter, redirecting, by the holographic combiner, the at least one
of the N instances of the first light signal towards a region of
the eye of the user that contains a pupil of the eye of the user
based on the gaze direction of the eye of the user determined by
the eye tracker.
[0022] The first light signal may include an image comprising at
least two pixels and redirecting respective ones of N instances of
the first light signal towards the holographic combiner by the
optical replicator may include redirecting N respective instances
of a same image towards the holographic combiner by the optical
replicator.
[0023] Redirecting respective ones of N instances of the first
light signal towards the holographic combiner by the optical
replicator may include redirecting N respective instances of a same
pixel in a different instance of a same image towards the
holographic combiner by the optical replicator.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0024] 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.
[0025] 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.
[0026] FIG. 2A is an illustrative diagram of a wearable heads-up
display in operation showing eyebox expansion by exit pupil
replication in accordance with the present systems, devices, and
methods.
[0027] FIG. 2B is an illustrative diagram of the wearable heads-up
display from FIG. 2A showing eyebox expansion by exit pupil
replication for a sweep of the total scan range .theta. of the
scanning laser projector in accordance with the present systems,
devices, and methods.
[0028] FIG. 2C is an illustrative diagram of the wearable heads-up
display from FIGS. 2A and 2B showing eyebox expansion by exit pupil
replication with respective instances of the same display content
projected spatially in parallel with one another towards respective
exit pupils in accordance with the present systems, devices, and
methods.
[0029] FIG. 3A is an illustrative diagram of a wearable heads-up
display in operation showing eyebox expansion by exit pupil
replication and a controllable shutter mechanism in accordance with
the present systems, devices, and methods.
[0030] FIG. 3B is an illustrative diagram of the wearable heads-up
display from FIG. 3A showing an operation of the controllable
shutter for a sweep of the total scan range .theta. of the scanning
laser projector in accordance with the present systems, devices,
and methods.
[0031] FIG. 4 is an illustrative diagram showing an exemplary
holographic combiner in two-dimensions converging four instances of
replicated light signals to form an expanded eyebox comprising four
spatially-separated exit pupils at or proximate the eye of a user
in accordance with the present systems, devices, and methods.
[0032] FIG. 5 is an illustrative diagram of a wearable heads-up
display in operation showing eyebox expansion by exit pupil
replication using an exemplary optical replicator in accordance
with the present systems, devices, and methods.
[0033] FIG. 6 is a flow-diagram showing a method of operating a
wearable heads-up display in accordance with the present systems,
devices, and methods.
DETAILED DESCRIPTION
[0034] 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.
[0035] 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."
[0036] 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.
[0037] 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.
[0038] The headings and Abstract of the Disclosure provided herein
are for convenience only and do not interpret the scope or meaning
of the embodiments.
[0039] The various embodiments described herein provide systems,
devices, and methods for eyebox expansion in scanning laser-based
wearable heads-up displays ("WHUDs"). Generally, a scanning
laser-based WHUD is a form of virtual retina display in which a
scanning laser projector ("SLP") draws a raster scan onto the eye
of the user. In the absence of any further measure the SLP 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
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
SLP (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 scanning laser-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).
[0040] The eyebox of a scanning laser-based WHUD is defined by the
geometry of the exit pupil of the display at or proximate the eye
of the user. A scanning laser-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 scanning
laser-based WHUD may be expanded by optically replicating 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 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
scanning laser-based WHUDs.
[0041] 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.
[0042] 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 SLP 120, a holographic combiner 130, and an optical
replicator 150. Portions of SLP 120 and optical replicator 150 may
be contained within an inner volume of support structure 110;
however, FIG. 1 provides a partial-cutaway view in which regions of
support structure 110 have been removed in order to render visible
portions of SLP 120 and optical replicator 150 that may otherwise
be concealed.
[0043] Throughout this specification and the appended claims, the
term "carries" and variants such as "carried by" are generally used
to refer to a physical coupling between two objects. The physical
coupling may be direct physical coupling (i.e., with direct
physical contact between the two objects) or indirect physical
coupling that may be mediated by one or more additional objects.
Thus, the term carries and variants such as "carried by" are meant
to generally encompass all manner of direct and indirect physical
coupling, including without limitation: carried on, carried within,
physically coupled to, and/or supported by, with or without any
number of intermediary physical objects therebetween.
[0044] SLP 120 may include multiple laser diodes (e.g., a red laser
diode, a green laser diode, and/or a blue laser diode) and at least
one scan mirror (e.g., a single two-dimensional scan mirror or two
one-dimensional scan mirrors, which may be, e.g., MEMS-based or
piezo-based). SLP 120 may be communicatively coupled to (and
support structure 110 may further carry) a processor and a
non-transitory processor-readable storage medium or memory storing
processor-executable data and/or instructions that, when executed
by the processor, cause the processor to control the operation of
SLP 120. For ease of illustration, FIG. 1 does not call out a
processor or a memory.
[0045] Holographic combiner 130 is positioned within a field of
view of at least one eye of the user when support structure 110 is
worn on the head of the user. Holographic combiner 130 is
sufficiently optically transparent to permit light from the user's
environment (i.e., "environmental light") to pass through to the
user's eye. In the illustrated example of FIG. 1, support structure
110 further carries a transparent eyeglass lens 140 (e.g., a
prescription eyeglass lens) and holographic combiner 130 comprises
at least one layer of holographic material that is adhered to,
affixed to, laminated with, carried in or upon, or otherwise
integrated with eyeglass lens 140. The at least one layer of
holographic material may include a photopolymer film such as
Bayfol.RTM.HX available from Bayer MaterialScience AG or a silver
halide compound and may, for example, be integrated with
transparent lens 140 using any of the techniques described in U.S.
Provisional Patent Application Ser. No. 62/214,600. Holographic
combiner 130 includes at least one hologram in or on the at least
one layer of holographic material. With holographic combiner 130
positioned in a field of view of an eye of the user when support
structure 110 is worn on the head of the user, the at least one
hologram of holographic combiner 130 is positioned and oriented to
redirect light originating from SLP 120 towards the eye of the
user. In particular, the at least one hologram is positioned and
oriented to receive light signals that originate from SLP 120 and
converge those light signals to at least one exit pupil at or
proximate the eye of the user.
[0046] Optical replicator 150 is positioned in an optical path
between SLP 120 and holographic combiner 130. Optical replicator
150 comprises at least one optical element (e.g., at least one
lens, reflector, partial reflector, prism, diffractor, diffraction
grating, mirror, or other optical element, or at least one
configuration, combination, and/or arrangement of such) that is
arranged to receive light signals generated and output by SLP 120,
produce multiple (e.g., N, where N is an integer greater than 1)
copies or instances of the light signals, and redirect respective
ones of the N instances of the light signals towards holographic
combiner 130. Advantageously, optical replicator 150 may be a
static and passive component that, without power consumption or any
moving parts, receives as an input a light signal generated by SLP
120 and provides as outputs N replicated instances of that light
signal, the N replicated instances of the light signal temporally
substantially in parallel with one another and, as will be
described in more detail later on, spatially separated from one
another so that each one of the N instances appears to originate
(i.e., "effectively" originates) from a respective one of N
different spatially-separated "virtual positions" for SLP 120 as
opposed to appearing to originate from the real position for SLP
120.
[0047] Throughout this specification and the appended claims,
reference is often made to one or more "virtual position(s)" such
as "N spatially-separated virtual positions for a SLP." The "real
position" of an object is its actual position in real, three
dimensional space. A "virtual position" of an object is a position
in real space at which the optics of a system cause light from the
object to effectively originate even though the real position of
the object may be elsewhere. In other words, the optics of the
system cause light from the object to follow optical paths that
would trace back, if the optics of the system were ignored during
the trace back, to a "virtual position" in space that is
spatially-separated from the object's "real position" in space. As
a simple example, an object in front of a planar mirror has a
"virtual position" on the other side of the planar mirror. A
"virtual position" may be a result of one or more intervening
optical element(s) in an optical path. When one or more optical
element(s) redirects light signals from a SLP, a virtual position
for the SLP refers to the position in real space at which the SLP
would need to be located in order to provide light signals having
that same trajectory without any intervening optics. The optics of
the system cause the light signals to follow a trajectory that
would correspond to a different point of origin if there were no
such optics in the system. The light signals appear to have
"effectively" originated from a different, or "virtual," position
for the SLP.
[0048] FIG. 2A is an illustrative diagram of a WHUD 200 in
operation showing eyebox expansion by exit pupil replication in
accordance with the present systems, devices, and methods. WHUD 200
may be substantially similar to WHUD 100 from FIG. 1, although in
FIG. 2A no support structure (e.g., support structure 110) is
illustrated in order to reduce clutter. As with WHUD 100, WHUD 200
comprises a SLP 220 (which includes a RGB laser module 221 and at
least one MEMS-based scan mirror 222), a holographic combiner 230
carried by an eyeglass lens 240, and the optical replicator 250. As
previously described, the combination of holographic combiner 230
and eyeglass lens 240 is sufficiently transparent to allow
environmental light 295 to pass through to the eye 290 of the
user.
[0049] SLP 220 is located at a first position 260 (i.e., a "real"
position) relative to holographic combiner 230 and is shown
generating (e.g., projecting) a first light signal 270. Optical
replicator 250 is positioned in an optical path between SLP 220 and
holographic combiner 230 such that optical replicator 250
interrupts (e.g., receives) light signal 270 en route from SLP 220
to holographic combiner 230. As previously described, optical
replicator 250 includes at least one optical element (e.g., at
least one lens, reflector, partial reflector, prism, diffractor,
diffraction grating, mirror, or other optical element, or at least
one configuration, combination, and/or arrangement of such) that is
arranged to receive light signal 270 from SLP 220 and redirect
respective ones of N instances of light signal 270 towards
holographic combiner 230. In the illustrated example of FIG. 2A,
optical replicator 250 redirects four instances (i.e., N=4) of
light signal 270 towards holographic combiner 230: instance 271 of
light signal 270 represented by lines with large dashes, instance
272 of light signal 270 represented by solid lines, instance 273 of
light signal 270 represented by dotted lines, and instance 274 of
light signal 270 represented by lines having alternating large and
short dashes. Four instances of light signal 270 (i.e., N=4) are
used as an example for illustrative purposes only in FIG. 2A. In
alternative implementations any number of instances of a light
signal may be produced by an optical replicator in accordance with
the present systems, devices, and methods (e.g., N may be any
integer greater than 1 depending on the specific
implementation).
[0050] SLP 220 is positioned at a first real position 260 in real
space relative to holographic combiner 230. Optical replicator 250
(e.g., at least one optical element thereof) is arranged to
redirect respective ones of the N=4 instances 271, 272, 273, and
274 of light signal 270 towards holographic combiner 230
effectively from respective ones of N=4 spatially-separated virtual
positions 261, 262, 263, and 264 for SLP 220. Specifically, optical
replicator redirects (e.g., is arranged to redirect) first instance
271 of light signal 270 towards holographic combiner 230
effectively from first virtual position 261 for SLP 220, second
instance 272 of light signal 270 towards holographic combiner 230
effectively from second virtual position 262 for SLP 220, third
instance 273 of light signal 270 towards holographic combiner 230
effectively from third virtual position 263 for SLP 220, and fourth
instance 274 of light signal 270 towards holographic combiner 230
effectively from fourth virtual position 264 for SLP 220. Each
respective one of the N=4 virtual positions 261, 262, 263, and 264
for SLP 220 effectively established by optical replicator 250 is
spatially-separated from the other ones of the N=4 virtual
positions 261, 262, 263, and 264 for SLP 220 so that each
respective instance 271, 272, 273, and 274 of light signal 270
effectively impinges on holographic combiner 230 from a different
position in space. Advantageously, each of the N=4 virtual
positions 261, 262, 263, and 264 for SLP 220 may correspond to a
respective position and orientation of SLP 220. In other words,
relative to the other ones of the N=4 virtual positions 261, 262,
263, and 264 for SLP 220, each one of the virtual positions 261,
262, 263, and 264 may correspond to a respective displacement and
rotation of SLP 220. Such is the case in WHUD 200 for which, as
would be apparent to one of ordinary skill in the art, a line
connecting each of the N=4 virtual positions 261, 262, 263, and 264
for SLP 220 in FIG. 2A would be a curved line.
[0051] Each one of the N=4 instances 271, 272, 273, and 274 of
light signal 270 is output by optical replicator 250 and received
by holographic combiner 230. As previously described, holographic
combiner 230 includes at least one hologram that is operative
(e.g., designed, crafted, encoded, recorded, and/or generally
positioned and oriented) to redirect each one of the N=4 instances
271, 272, 273, and 274 of light signal 270 towards eye 290 of the
user. Advantageously, the at least one hologram of holographic
combiner 230 may converge each one of the N=4 instances 271, 272,
273, and 274 of light signal 270 to a respective one of N=4 exit
pupils 281, 282, 283, and 284 at or proximate eye 290 of the user.
Specifically: optical replicator 250 directs first instance 271 of
light signal 270 towards holographic combiner 230 effectively from
first virtual position 261 for SLP 220 and holographic combiner 230
converges first instance 271 of light signal 270 to first exit
pupil 281 at or proximate eye 290; optical replicator 250 directs
second instance 272 of light signal 270 towards holographic
combiner 230 effectively from second virtual position 262 for SLP
220 and holographic combiner 230 converges second instance 272 of
light signal 270 to second exit pupil 282 at or proximate eye 290;
optical replicator 250 directs third instance 273 of light signal
270 towards holographic combiner 230 effectively from third virtual
position 263 for SLP 220 and holographic combiner 230 converges
third instance 273 of light signal 270 to third exit pupil 283 at
or proximate eye 290; and optical replicator 250 directs fourth
instance 274 of light signal 270 towards holographic combiner 230
effectively from fourth virtual position 264 for SLP 220 and
holographic combiner 230 converges fourth instance 274 of light
signal 270 to fourth exit pupil 284 at or proximate eye 290. The
eyebox 280 of WHUD 200 is given by the total range of pupil
positions (or gaze directions) for eye 290 in which at least one of
exit pupils 281 282, 283, and/or 284 aligns with and/or impinges on
the pupil of eye 290. Without optical replicator 250, a single
instance of light signal 270 (e.g., second instance 272) would
impinge on eye 290 at a single exit pupil (e.g., second exit pupil
282) to provide a relatively small eyebox. In such a configuration,
displayed content would disappear from the user's point of view if
and when the user gazed in a direction that caused the pupil of eye
290 to move away from the single exit pupil (e.g., second exit
pupil 282). In accordance with the present systems, devices, and
methods, optical replicator 250 replicates light signal 270 to
produce N=4 (where 4 is an illustrative example) instances 271,
272, 273, and 274 of light signal 270 and because each of these
four instances 271, 272, 273, and 274 effectively originates from a
different spatially-separated virtual position 261, 262, 263, and
264, respectively, for SLP 220, holographic combiner 230 converges
each of these four instances 271, 272, 273, and 274 to a respective
spatially-separated exit pupil 281, 282, 283, and 284 at or
proximate eye 290. Spatially-separated exit pupils 281, 282, 283,
and 284 are distributed over an area of eye 290 that covers a wider
range of pupil positions (e.g., gaze directions) than a single exit
pupil (of the same size as any one of exit pupils 281, 282, 283 and
284) on its own. Thus, eyebox 280 is expanded by exit pupil
replication in WHUD 200.
[0052] Generally, first light signal 270 shown in FIG. 2A may
embody a variety of different forms, including without limitation:
a single light signal, a single pixel of an image, multiple pixels
of an image, or an image itself that comprises at least two pixels.
When first light signal 270 corresponds to an image (e.g.,
comprising at least two pixels), each one of the N=4 instances 271,
272, 273, and 274 of first light signal 270 produced by optical
replicator 250 may include a respective instance of the same image.
When first light signal 270 corresponds to one or more pixel(s) of
an image, each one of the N=4 instances 271, 272, 273, and 274 of
first light signal 270 may include a respective instance of the
same one or more pixel(s) in a different instance of the same
image.
[0053] FIG. 2B is an illustrative diagram of WHUD 200 from FIG. 2A
showing eyebox expansion by exit pupil replication for a sweep of
the total scan range .theta. of SLP 220 in accordance with the
present systems, devices, and methods. FIG. 2B shows a different
stage of operation of the same WHUD 200 from FIG. 2A. Many of the
same elements from FIG. 2A are also included in FIG. 2B but only
those elements that are particular to the description of FIG. 2B
that follows are called out in FIG. 2B.
[0054] In the operation of WHUD 200 depicted in FIG. 2B, SLP 220
sweeps through its total scan range .theta.. Throughout this
specification and the appended claims, the "total scan range" of a
SLP refers to the full range of angles and/or directions at which
the SLP is operative to project light signals during normal use and
is generally determined by the range of motion of the at least one
scan mirror 222 in the SLP 220. The SLPs described herein are
generally operative to draw a raster scan and the "total scan
range" generally encompasses the outer perimeter of the full raster
scan that the SLP is operative to draw. This may be accomplished
by, for example, a SLP that employs a single scan mirror operative
to scan in two orthogonal dimensions or two separate scan mirrors
that are each operative to scan in a respective one of two
orthogonal dimensions. An exemplary SLP may have a total scan range
.theta. comprising a first scan range in a first dimension (e.g.,
in a horizontal dimension) and a second scan range in a second
dimension (e.g., in a vertical dimension). The first and second
scan ranges may each be between 0.degree. and 180.degree., although
in practice each may be within a narrower range, such as between
10.degree. and 60.degree.. The relative scan ranges in the first
and second dimensions influence the aspect ratio of the WHUD.
[0055] Optical replicator 250 of WHUD 200 is positioned in the
optical path (e.g., in all the optical paths) between SLP 220 and
holographic combiner 230 for the total scan range .theta. of SLP
220. At least one optical element of optical replicator 250 is
arranged to receive all of the light signals (e.g., a single
optical element may be arranged to receive all of the light signals
or multiple optical elements may arranged to all receive all of the
light signals, or multiple optical elements may be arranged so that
each light signal is received by at least one of the multiple
optical elements) generated by SLP 220 during a sweep of the total
scan range .theta. by SLP 220 and redirect respective ones of N
(e.g., N=4 in the illustrated example) instances of all of the
light signals towards holographic combiner 230. In other words, in
a similar way to how a first light signal 270 is replicated by
optical replicator 250 as four instances 271, 272, 273, and 274 of
the first light signal 270 in the exemplary operation of WHUD 200
illustrated in FIG. 2A, FIG. 2B illustrates an exemplary operation
of WHUD 200 in which all light signals corresponding to a first
sweep of the total scan range .theta. of SLP 220 are replicated by
optical replicator 250 as four instances of all light signals
corresponding to the sweep of the total scan range .theta. of SLP
220. The four instances of all light signals corresponding to the
total scan range .theta. are not called out in FIG. 2B to reduce
clutter but are drawn using the same distinguishable lines as used
to distinguish between the different instances 271, 272, 273, and
274 of first light signal 270 in FIG. 2A. That is, a first instance
of all light signals corresponding to the sweep of the total scan
range .theta. (represented by lines with large dashes) is
redirected by optical replicator 250 towards holographic combiner
230 from first virtual position 261 for SLP 220, a second instance
of all light signals corresponding to the sweep of the total scan
range .theta. (represented by solid lines) is redirected by optical
replicator 250 towards holographic combiner 230 from second virtual
position 262 for SLP 220, a third instance of all light signals
corresponding to the sweep of the total scan range .theta.
(represented by dotted lines) is redirected by optical replicator
250 towards holographic combiner 230 from third virtual position
263 for SLP 220, and a fourth instance of all light signals
corresponding to the sweep of the total scan range .theta.
(represented by lines with alternating large and short dashes) is
redirected by optical replicator 250 towards holographic combiner
230 from fourth virtual position 264 for SLP 220. At least one
hologram of holographic combiner 230 receives the N=4 instances of
all light signals corresponding to the sweep of the total scan
range .theta. of SLP 220 and converges each respective instance of
all light signals corresponding to the sweep of the total scan
range .theta. of SLP 220 to a respective one of the N=4 exit pupils
281, 282, 283, and 284 at or proximate eye 290.
[0056] In FIG. 2A, the N=4 instances 271, 272, 273, and 274 of
first light signal 270 are all shown incident at or on about the
same region of holographic combiner 230. Likewise, in FIG. 2B the
N=4 instances of all light signals corresponding to the sweep of
the total scan range .theta. of SLP 220 are all shown incident over
the same completely-overlapping area of holographic combiner 230.
In both cases, this configuration is exemplary and in practice
alternative configurations may be preferred depending on the
specific implementation. Generally, each instance of all light
signals corresponding to a sweep of the total scan range .theta. of
SLP 220 may be incident upon (and received by) a respective region
or area of holographic combiner 230 and these respective areas of
holographic combiner 230 may or may not completely overlap (e.g.,
such areas may partially overlap or correspond to separate,
non-overlapping areas).
[0057] In a virtual retina display such as scanning laser-based
WHUD 100 and/or scanning laser-based WHUD 200, there may not be an
"image" formed outside of the eye of the user. There is typically
no microdisplay or projection screen or other place where the
projected image is visible to a third party; rather, the image may
be formed completely within the eye of the user. For this reason,
it may be advantageous for a scanning laser-based WHUD to be
designed to accommodate the manner in which the eye forms an
image.
[0058] For a light signal entering the eye (e.g., a light ray, a
wavefront, an incident beam from a SLP, or similar), the eye (or
more accurately, the combination of the eye and the human brain)
may determine "where" the light signal is positioned in the user's
field of view based on the region of the retina that is illuminated
by the light signal. Two light signals that illuminate the same
region of the retina may appear in the same position in the user's
field of view. The particular region of the retina that is
illuminated by any given light signal is determined by the angle
and not the location at which the light signal enters the eye.
Thus, two light signals may appear in the same position in the
user's field of view even if they enter different location of the
user's pupil provided that the two light signals have the same
angle of incidence when they enter the user's eye. The geometry of
the eye's lens is such that any two light signals entering the eye
at the same angle, regardless of the position/location at which the
light signals enter the eye, may generally be directed to the same
region of the retina and so may generally appear in the same
position in the user's field of view.
[0059] In at least some implementations, the scanning laser-based
WHUDs described herein project multiple instances of the same image
onto the retina of the eye substantially concurrently. Even if the
multiple instances are temporally-separated, the temporal
separation may be small enough to be undetectable by the user. If
any two of the multiple instances of the same image do not
align/overlap on the eye's retina then those two instances of the
image may not align/overlap in the user's field of view and
undesirable effects such as ghosting can occur. In order to ensure
that multiple instances of the same image (each corresponding to a
respective exit pupil) align/overlap on the retina so that multiple
instances of the image align/overlap in the user's field of view, a
scanning laser-based WHUD may advantageously be configured to
direct multiple instances of any given light signal (each
corresponding to a respective exit pupil and each representing a
respective instance of the same display content) towards the eye
spatially in parallel with one another. More specifically and
referring to FIG. 2A, the optical replicator 250 and/or the
holographic combiner 230 may be configured (either individually or
in combination) so that the holographic combiner 230 redirects the
N=4 instances 271, 272, 273, and 274 of the first light signal 270
all spatially in parallel with one another towards respective
regions (i.e., towards respective ones of N=4 spatially-separated
exit pupils 281, 282, 283, and 284 from FIG. 2B) of the eye 290 of
the user.
[0060] FIG. 2C is an illustrative diagram of WHUD 200 from FIGS. 2A
and 2B showing eyebox expansion by exit pupil replication with
respective instances of the same display content (e.g., pixel(s))
projected spatially in parallel with one another towards respective
exit pupils in accordance with the present systems, devices, and
methods. In order to highlight some of the features shown in the
implementation of FIG. 2C, the corresponding aspects of FIG. 2B
will first be noted.
[0061] In the implementation of FIG. 2B, respective ones of the N=4
instances of all light signals corresponding to a sweep of the
total scan range .theta. of SLP 220 all align with one another and
completely overlap on holographic combiner 230. As a result, each
of the N=4 exit pupils 281, 282, 283, and 284 converges at or
proximate eye 290 from substantially the same area of holographic
combiner 230. Because each of the N=4 exit pupils 281, 282, 283,
and 284 originates from substantially the same area of holographic
combiner 230 but converges to a respective spatially-separated
region of eye 290, each of the N=4 exit pupils 281, 282, 283, and
284 necessarily includes at least some light signals having
incident angles (at eye 290) that cannot be provided by at least
one other one of the N=4 exit pupils 281, 282, 283, and 284. For
example, the light signals (represented by lines with large dashes)
that converge to exit pupil 281 include at least some angles of
incidence that are not included in the light signals (represented
by solid lines) that converge to exit pupil 282, and vice versa. As
previously described, the angle of incidence of a light signal as
it enters the eye determines where in the user's field of view the
light (or the pixel of an image embodied by the light signal) will
appear. A light signal having an angle of incidence that is unique
to one exit pupil can only be projected to a user when that exit
pupil aligns with the user's pupil (e.g., when the user's gaze
direction includes that exit pupil). Thus, when multiple
spatially-separated exit pupils all originate from substantially
the same spatial area on holographic combiner 230, only a limited
sub-region of that spatial area may be used to provide angles of
incidence that are common to all of the exit pupils and,
consequently, only a limited fraction of the total scan range
.theta. of the SLP 220 may be used to provide uniform image
replication across all of the spatially-separated exit pupils.
Having all of the N=4 instances of the total scan range .theta. of
SLP 220 align and overlap on holographic combiner 230 can simplify
some aspects of the design of optical replicator 250 and/or
holographic combiner 230 but can also limit the available
resolution and/or field of view of SLP 220 that can be replicated
across all exit pupils.
[0062] In the implementation of FIG. 2C, optical replicator 250 is
modified (e.g., in geometry, orientation, and/or composition) to
shift the relative trajectories of the N=4 instances of all light
signals corresponding to a sweep of the total scan range .theta. of
SLP 220 compared to their corresponding trajectories in the
implementation of FIG. 2B. The N=4 instances of all light signals
corresponding to a sweep of the total scan range .theta. of SLP 220
(respectively represented by different line types in FIG. 2C as in
FIG. 2B) do not align or completely overlap on holographic combiner
230 in FIG. 2C as they do in FIG. 2B. Instead, the N=4 instances of
the total scan range .theta. of SLP 220 are spatially distributed
over the area of holographic combiner 230 and each positioned so
that the respective corresponding light signals are all
substantially parallel to one another when redirected and converged
by holographic combiner 230 towards respective ones of the N=4
spatially-separated exit pupils 281, 282, 283, and 284 at or
proximate eye 290. That is, the light signals that are converged by
holographic combiner 230 to each respective one of the N=4 exit
pupils 281, 282, 283, and 284 all include the same angles of
reflection from holographic combiner 230 and accordingly the same
angles of incidence with respect to eye 290. In contrast to the
implementation of FIG. 2B, in the implementation of FIG. 2C none of
the N=4 exit pupils 281, 282, 283, and 284 includes a light signal
having an angle of incidence (with respect to eye 290, or an angle
of reflection with respect to holographic combiner 230) that is not
also included in each of the other ones of the N=4 exit pupils 281,
282, 283, and 284. Each of the N=4 exit pupils 281, 282, 283, and
284 of the implementation in FIG. 2C includes the entire scan range
.theta. of SLP 220 and therefore the implementation of WHUD 200
depicted in FIG. 2C can provide uniform image replication across
multiple exit pupils with larger field of view and/or higher
resolution than the implementation of WHUD 200 depicted in FIG. 2B,
at the cost of added complexity in optical replicator 250 and/or
holographic combiner 230.
[0063] As previously described, holographic combiner 230 comprises
at least one hologram embedded, encoded, recorded, or otherwise
carried by at least one layer of holographic film. The holographic
film may include, as examples, a photopolymer film such as
Bayfol.RTM.HX from Bayer MaterialScience AG or a silver halide
compound. The nature of the at least one hologram may depend on the
specific implementation.
[0064] As a first example, holographic combiner 230 may include a
single hologram that effectively operates as a fast-converging
(e.g., convergence within about 1 cm, convergence with about 2 cm,
or convergence within about 3 cm) mirror for light having the
wavelength(s) provided by SLP 220. In this first example, the
holographic film that carries the first hologram may have a
relatively wide bandwidth, meaning the hologram recorded in the
holographic film may impart substantially the same optical effect
or function on all light signals projected by SLP 220 over a
relatively wide range of angles of incidence at holographic
combiner 230. For the purpose of the present systems, devices, and
methods, the term "wide bandwidth" in relation to holograms and
holographic films means an angular bandwidth that is greater than
or equal to the total range of angles of incidence of all light
signals received by any given point, region, or location of the
hologram or holographic film from an optical replicator. As an
example, WHUD 200 may implement a wide bandwidth hologram in
holographic combiner 230 having an angular bandwidth of greater
than or equal to about 8.degree.. In this case, the spatial
separation between virtual positions 261, 262, 263, and 264 may be
such that any given point, region, or location of holographic
combiner 230 receives light signals (i.e., spanning all instances
271, 272, 273, and 274) spanning an 8.degree. (or less) range of
angles of incidence at holographic combiner 230.
[0065] Consistent with conventional mirror behavior, for a single
wide-bandwidth fast-converging hologram carried by holographic
combiner 230 the angles of incidence for a range of light signals
incident on holographic combiner 230 may influence the angles of
reflection for that range of light signals redirected by
holographic combiner 230. Since holographic combiner 230 is,
generally during normal operation of WHUD 200, fixed in place
relative to SLP 220, the angles of incidence for a range of light
signals are determined, at least in part, by the particular virtual
position 261, 262, 263, or 264 for the SLP 220 from which optical
replicator 250 causes the range of light signals to effectively
originate. The spatial position of the exit pupil 281, 282, 283, or
284 to which the range of light signals is converged by holographic
combiner 230 is then determined, at least in part, by the angles of
reflection of that range of light signals from holographic combiner
230. Each one of virtual positions 261, 262, 263, and 264 provides
light signals over a respective range of angles of incidence
(generally but not necessarily with at least some overlap) at
holographic combiner 230 and therefore holographic combiner 230
converges light signals from each one of virtual positions 261,
262, 263, and 264 to a respective one of exit pupils 281, 282, 283,
and 284. This is why, referring to FIG. 2B for example, the
instance of the total scan range .theta. of SLP 220 that
effectively originates from virtual position 261 (represented by
lines with large dashes) with a range of relatively small angles of
incidence (compared to the other instances of the total scan range
.theta. of SLP 220 that effectively originate from virtual
positions 262, 263, and 264) maps to exit pupil 281 with a range of
relatively small angles of reflection (compared to the other exit
pupils 282, 283, and 284) and the instance of the total scan range
.theta. of SLP 220 that effectively originates from virtual
position 264 (represented by lines with alternating large and short
dashes) with a range of relatively large angles of incidence
(compared to the other instances of the total scan range .theta. of
SLP 220 that effectively originate from virtual positions 261, 262,
and 263) maps to exit pupil 284 with a range of relatively large
angles of reflection (compared to the other exit pupils 281, 282,
and 283).
[0066] As a second example, rather than a single hologram,
holographic combiner 230 may instead include any number of
multiplexed holograms. Multiplexed holograms may be advantageous
when, for example, multiple wavelengths of light signals are used
(e.g., red, green, and blue light signals generated by SLP 220)
and/or to provide a further means to separate light signals
effectively originating from different virtual positions for SLP
220. The "single hologram" example described above may be suitable
for an implementation in which SLP 220 only provides light signals
of a single wavelength (e.g., only red light signals, only green
light signals, or only blue light signals), but for implementations
in which SLP 220 provides light signals of multiple wavelengths it
may be advantageous for holographic combiner 230 to include a
respective wavelength multiplexed hologram for each respective
wavelength of light signals provided by SLP 220 (e.g., each
respective nominal wavelength of light signals provided by SLP 220,
since a laser diode may generally provide light signals over a
narrow waveband). Thus, when SLP 220 includes three different laser
diodes each providing light signals of a respective nominal
wavelength (e.g., a red laser diode, a green laser diode, and a
blue laser diode) it may be advantageous for holographic combiner
230 to include three wavelength-multiplexed holograms (e.g., a red
hologram, a green hologram, and a blue hologram) each designed to
work (e.g., "playback") for light signals having a respective one
of the three nominal wavelengths. In this example, at least one
"red hologram" (i.e., at least one hologram that is designed to
playback for light signals having a wavelength that corresponds to
red light) may converge a respective red component of each one of
the N=4 instances of the total scan range .theta. of SLP 220 to a
respective one of the N=4 exit pupils 281, 282, 283, and 284, at
least one "green hologram" (i.e., at least one hologram that is
designed to playback for light signals having a wavelength that
corresponds to green light) may converge a respective green
component of each one of the N=4 instances of the total scan range
.theta. of SLP 220 to a respective one of the N=4 exit pupils 281,
282, 283, and 284, and at least one blue hologram (i.e., at least
one hologram that is designed to playback for light signals having
a wavelength that corresponds to blue light) may converge a
respective blue component of each one of the N=4 instances of the
total scan range .theta. of SLP 220 to a respective one of the N=4
exit pupils 281, 282, 283, and 284.
[0067] As a third example, either apart from or in addition to
multiple wavelength-multiplexed holograms, holographic combiner 230
may include at least N angle-multiplexed holograms. That is, for an
implementation with N=4 virtual positions 261, 262, 263, and 264
for the SLP 220 and N=4 exit pupils 281, 282, 283, and 284,
holographic combiner 230 may include at least N=4 angle-multiplexed
holograms (or N=4 sets of angle-multiplexed holograms when
wavelength multiplexing is also employed, as discussed later on).
Each of the N=4 angle-multiplexed holograms may be designed to
playback for light signals effectively originating from a
respective one of the N=4 virtual positions 261, 262, 263, and 264
for SLP 220 and converge such light signals to a respective one of
the N=4 exit pupils 281, 282, 283, and 284. That is, a first
angle-multiplexed hologram may be designed to playback for light
signals effectively originating from first virtual position 261 for
SLP 220 and converge such light signals to first exit pupil 281, a
second angle-multiplexed hologram may be designed to playback for
light signals effectively originating from second virtual position
262 for SLP 220 and converge such light signals to second exit
pupil 282, a third angle-multiplexed hologram may be designed to
playback for light signals effectively originating from third
virtual position 263 for SLP 220 and converge such light signals to
third exit pupil 283, and a fourth angle-multiplexed hologram may
be designed to playback for light signals effectively originating
from fourth virtual position 264 for SLP 220 and converge such
light signals to fourth exit pupil 284.
[0068] For implementations that employ angle-multiplexing, it may
be advantageous for the holographic film that includes an
angle-multiplexed hologram to be of relatively narrow bandwidth.
Particularly, it may be advantageous for the holographic film to
have an angular bandwidth that is less than or about equal to the
minimum difference between the respective angles of incidence of
two light signals that are incident on the same point, region, or
location of holographic combiner 230 but effectively originate from
different virtual positions 261, 262, 263. 264. As an example, WHUD
200 may implement a narrow bandwidth angle-multiplexed hologram in
holographic combiner 230 having an angular bandwidth of less than
or equal to about 4.degree.. In this case, the difference between
the angle of incidence (at holographic combiner 230) of a first
instance 271 of a light signal that effectively originates from
virtual position 261 and is incident at a first point on
holographic combiner 230 and the angle of incidence (at holographic
combiner 230) of a second instance 272 of a (different) light
signal 272 that effectively originates from virtual position 262
and is incident at the same first point on holographic combiner 230
may be less than or equal to about 4.degree.. In this way, each
respective angle-multiplexed hologram in holographic combiner 230
may be designed to substantially exclusively playback for light
signals effectively originating from a respective one of virtual
positions 261, 262, 263, and 264 for SLP 220 and to substantially
not playback (e.g., insubstantially playback) for light signals
effectively originating from the other ones of virtual positions
261, 262, 263, and 264 for SLP 220.
[0069] Generally, holographic combiner 230 may include at least N
multiplexed holograms and each one of the at least N multiplexed
holograms may converge a respective one of the N instances of a
light signal from optical replicator 250 to a respective one of N
exit pupils at or proximate the eye 290 of the user.
[0070] Some implementations may employ both wavelength multiplexing
and angle multiplexing. For example, an implementation that employs
angle multiplexing and light signals of multiple wavelengths (e.g.,
a multi-color SLP) may advantageously also employ wavelength
multiplexing. In this case, holographic combiner 230 may include 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. Each one of the at least N
angle-multiplexed red holograms may converge a respective red
component of each one of N instances of any given light signal to a
respective one of N exit pupils at or proximate the eye of the
user, each one of the at least N angle-multiplexed green holograms
may converge a respective green component of each one of N
instances of any given light signal to a respective one of N exit
pupils at or proximate the eye of the user, and each one of the at
least N angle-multiplexed blue holograms may converge a respective
blue component of each one of N instances of any given light signal
to a respective one of N exit pupils at or proximate the eye of the
user.
[0071] Implementations of holographic combiner 230 that employ
multiple multiplexed holograms may include multiple holograms in or
on a single layer (i.e., all in or on the same layer) of
holographic film or may include multiple layers of holographic film
with each layer of holographic film carrying at least one
respective hologram. Holographic combiner 230 may or may not
comprise at least one volumetric holographic optical element.
Generally, holographic combiner 230 may comprise a single layer of
holographic film that carries any number of holograms or
holographic combiner 230 may comprise multiple layers of
holographic film (e.g., multiple layers laminated together) with
each respective layer of holographic film carrying any number of
respective holograms.
[0072] Holographic combiner 230 may be substantially flat or planar
in geometry or, as illustrated in FIGS. 2A, 2B, and 2C, holographic
combiner 230 may embody some curvature. In some implementations,
holographic combiner 230 may embody curvature because holographic
combiner 230 is carried by a prescription eyeglass lens 240 that
has some curvature. When necessary, holographic combiner 230 may
include systems, devices, and/or methods for curved holographic
optical elements described in U.S. Provisional Patent Application
Ser. No. 62/268,892.
[0073] The various embodiments described herein provide systems,
devices, and methods for eyebox expansion by exit pupil replication
in scanning laser-based WHUDs. Each replicated exit pupil is
aligned to a respective spatially-separated position at or
proximate the eye of the user because the optical replicator that
replicates the light signals spatially separates the replicated
light signals so that each replicated light signal appears to
effectively originate from a different spatially-separated virtual
position for the SLP. The effect is substantially the same as if
multiple SLPs were used instead of the optical replicator, with
each SLP positioned in a respective one of the virtual positions
and with each SLP projecting a respective instance of a light
signal towards the holographic combiner; however, the use of the
optical replicator has considerable advantages in terms of power
savings and minimizing hardware bulk.
[0074] While the use of an optical replicator in lieu of multiple
spatially-separated SLPs has many advantages, one potential
drawback may arise from the fact that replicated instances of a
light signal necessarily all embody substantially the same light
signal. This can be problematic when, for example, each replicated
instance of an image is made to effectively originate from a
different spatially-separated virtual position for the SLP. In that
case, each replicated instance of the image may be subject to a
unique combination of optical distortions. For example, a first
replicated instance of an image effectively originating from a
first virtual position may be subject to a first set of optical
distortions (e.g., image skewing, keystoning, aberrations, and so
on) resulting from the unique path of the first instance of the
image through the optical replicator and/or from the range of
angles of incidence (at holographic combiner 230 and/or at eye 290)
that correspond to the first virtual position for the SLP, while a
second replicated instance of the image effectively originating
from a second virtual position may be subject to a second set of
optical distortions resulting from the unique path of the second
instance of the image through the optical replicator and/or from
the range of angles of incidence (at holographic combiner 230
and/or at eye 290) that correspond to the second virtual position
for the SLP. If the first and second replicated instances of the
image both correspond to the same initial version of the image
defined by the SLP then there may be no opportunity to optically
tune, adjust, correct, or otherwise compensate for distortions that
are specific to the individual first and second instances of the
image. Even though the replicated instances of the image may be
optically the same at definition, the resulting replicated
instances of the image seen by the user may not be the same because
each instance of the image may be subject to individual image
distortions. In accordance with the present systems, devices, and
methods, this problem may be overcome (if necessary) by including a
controllable shutter mechanism to controllably block all but one
instance of a projected light signal at any given time, the one
instance of the light signal that is not blocked by the shutter
corresponding to an instance of the light signal that converges to
a particular exit pupil that aligns with the user's gaze direction
at that time.
[0075] FIG. 3A is an illustrative diagram of a WHUD 300 in
operation showing eyebox expansion by exit pupil replication and a
controllable shutter mechanism 352 in accordance with the present
systems, devices, and methods. WHUD 300 may be substantially
similar to WHUD 200 from FIGS. 2A, 2B, and 2C with the following
additions: WHUD 300 includes an eye tracker 351 (carried by the
support structure of WHUD 300 which is not shown in FIG. 3A to
reduce clutter), positioned and oriented to determine a gaze
direction of the eye 390 of the user, and WHUD 300 includes at
least one controllable shutter 352 (carried by the support
structure of WHUD 300) positioned in at least one optical path
(e.g., in all optical paths) between the optical replicator 350 and
the holographic combiner 330.
[0076] In the illustrated operation of WHUD 300 depicted in FIG.
3A, a first light signal 370 is generated by the SLP 320 and
projected towards (e.g., into or onto) optical replicator 350. As
in WHUD 200, optical replicator 350 replicates first light signal
370 to produce N=4 (where 4 is again used only as a non-limiting
example) instances 371, 372, 373, and 374 of first light signal 370
and redirects the N=4 instances 371, 372, 373, and 374 of first
light signal 370 towards holographic combiner 330. However, as
previously described, each one of the N=4 instances 371, 372, 373,
and 374 of first light signal 370 may be subject to a respective
(e.g., unique) optical distortion or set of optical distortions
that may cause the corresponding instances of the image (or
portion(s) of the image) represented by first light signal 370 to
misalign if they are concurrently presented to the user. In
accordance with the present systems, devices, and methods, such
misalignment may be prevented by presenting only one of the N=4
instances 371, 372, 373, and 374 of first light signal 370 to the
user at any given time. To this end, eye tracker 351 determines the
position of the pupil of eye 390 (e.g., the gaze direction of the
user) and controllable shutter 352 is controllable to selectively
block all but at least one (e.g., 372 in FIG. 3A) of the N=4
instances 371, 372, 373, and 374 of first light signal 370
redirected towards holographic combiner 330 by optical replicator
350. The at least one (e.g., 372 in FIG. 3A) of the N=4 instances
371, 372, 373, and 374 of first light signal 370 that is not
blocked by controllable shutter 352 corresponds to the at least one
of the N=4 instances 371, 372, 373, and 374 of first light signal
370 that, when redirected by holographic combiner 330, is
redirected by holographic combiner 330 towards a region (exit pupil
382 in FIG. 3A) of the eye 390 of the user that contains a pupil of
eye 390 based on the gaze direction of eye 390 determined by eye
tracker 351. Thus, in response to eye tracker 351 determining that
the pupil of eye 390 aligns most with exit pupil 382 (relative to
the other available exit pupils in WHUD 300), controllable shutter
352 selectively permits only the second instance 372 of first light
signal 370 to pass through and be received and redirected by
holographic combiner 330. Controllable shutter 352 selectively
blocks first instance 371, third instance 373, and fourth instance
374 of first light signal 370 because first instance 371, third
instance 373, and fourth instance 374 of first light signal 370 all
map to exit pupils that do not align with the user's current gaze
direction and may contribute undesirable optical distortions to the
user's perception of the image (or portion(s) of the image)
represented by first light signal 370.
[0077] FIG. 3B is an illustrative diagram of WHUD 300 from FIG. 3A
showing an operation of controllable shutter 352 for a sweep of the
total scan range .theta. of SLP 320 in accordance with the present
systems, devices, and methods. The operation of controllable
shutter 352 may be synchronized with the operation of SLP 320 so
that controllable shutter 352 provides only a limited transmission
region therethrough at any given time and that limited transmission
region corresponds to the trajectory of the particular instance
(e.g., 373 in FIG. 3B) of a light signal generated by SLP 320 and
redirected by (e.g., rerouted by or routed through) optical
replicator 350 that will be redirected by holographic combiner 330
towards the particular exit pupil 383 that best aligns with the
current gaze direction of eye 390 as determined by eye tracker 351.
Thus, even though a sweep of the total scan range .theta. of SLP
320 spans multiple regions of controllable shutter 350,
controllable shutter 352 may be varied at a speed that
substantially matches the sweep speed of SLP 320 so that the
transmissive region of controllable shutter 352 moves with (e.g.,
follows) the sweep of the total scan range .theta. of SLP 320. In
this way, a single instance of a complete sweep of the total scan
range .theta. of SLP 320 may be transmitted through controllable
shutter 352 while the other replicated instances of the sweep of
the total scan range .theta. of SLP 320 may be blocked by
controllable shutter 352.
[0078] When a controllable shutter 352 is used to selectively
block/transmit individual ones of multiple N instances of a light
signal (e.g., based on the eye's pupil position as determined by an
eye tracker), the SLP may be calibrated to define each light signal
in such a way that the light signal accommodates, compensates for,
and/or generally accounts for the particular optical distortion(s)
that apply to the particular instance of the light signal that
current configuration of the controllable shutter 352 will
transmit. At least one of eye tracker 351 and/or controllable
shutter 352 may provide feedback about the current "active" exit
pupil of WHUD 300 and SLP 320 may selectively operate in a mode
that applies compensation and/or accommodation measures to light
signals in order to account for the optical distortion(s) that are
particular to the optical path(s) that correspond to the current
"active" exit pupil.
[0079] Controllable shutter 352 may comprise any of a variety of
different structures depending on the specific implementation. For
example, controllable shutter 352 may comprise one or more
MEMS-based or piezo-based elements for physically translating
and/or rotating one or more opaque surface(s) in the optical
path(s) between optical replicator 350 and holographic combiner
330, one or more controllable (e.g., translatable and/or rotatable)
reflector(s) or refractor(s), one or more controllable polarization
filter(s) together with one or more controllable polarizer(s) in
SLP 320 or between SLP 320 and controllable shutter 352, and so
on.
[0080] Eye tracker 351 may employ any of a variety of different eye
tracking technologies depending on the specific implementation. For
example, eye tracker 351 may employ any or all of the systems,
devices, and methods described in U.S. Provisional Patent
Application Ser. No. 62/167,767; U.S. Provisional Patent
Application Ser. No. 62/271,135; U.S. Provisional Patent
Application Ser. No. 62/245,792; and/or U.S. Provisional Patent
Application Ser. No. 62/281,041.
[0081] As previously described, WHUD 300 may include at least one
processor and at least one non-transitory processor-readable
storage medium or memory communicatively coupled thereto. The at
least one memory may store processor-executable data and/or
instructions that, when executed by the at least one processor,
cause the at least one processor to control the operation of any or
all of eye tracker 351, controllable shutter 352, and/or SLP
320.
[0082] The illustrative examples of the present systems, devices,
and methods depicted in FIGS. 2A, 2B, 2C, 3A, and 3B are all
generally shown in two-dimensions and generally illustrate eyebox
configurations in which multiple exit pupils are spatially
separated in one dimension across the eye of the user. In practice,
the expanded eyebox configurations described herein may comprise
any number N of replicated exit pupils arranged in any
two-dimensional configuration over the area of the eye of the user.
An example configuration with N=4 replicated exit pupils is
provided in FIG. 4.
[0083] FIG. 4 is an illustrative diagram showing an exemplary
holographic combiner 430 in two-dimensions converging four
instances of replicated light signals to form an expanded eyebox
480 comprising four spatially-separated exit pupils 481, 482, 483,
and 484 at or proximate the eye 490 of a user in accordance with
the present systems, devices, and methods. Exit pupils 481, 482,
483, and 484 are distributed over a two-dimensional area at or near
eye 490 to cover a wide range of pupil positions (e.g., gaze
directions) for eye 490. As long as the pupil of eye 490 is
positioned within eyebox 480, at least one of exit pupils 481, 482,
483, and 484 (in some cases a combination of at least two of exit
pupils 481, 482, 483, and 484) will provide light signals through
the pupil to eye 490 and the user will be able to see the projected
image. In terms of optical path, each one of exit pupils 481, 482,
483, and 484 may receive light signals corresponding to a
respective replicated instance of the total scan range .theta. of
an SLP.
[0084] Exemplary optical replicators 250 and 350 drawn in FIGS. 2A,
2B, 2C, 3A and 3B are faceted, prismatic structures. Such
structures are shown for illustrative purposes only and not
intended to limit the composition of the optical replicators
described herein to prismatic, faceted structures or structures of
similar geometry. While faceted, prismatic structures may be
suitable as optical replicators in certain implementations, as
previously described the optical replicators described herein may
comprise any of a variety of different components depending on the
specific implementation. A non-limiting example of the construction
and operation of an optical replicator as described herein is
provided in FIG. 5.
[0085] FIG. 5 is an illustrative diagram of a WHUD 500 in operation
showing eyebox expansion by exit pupil replication using an
exemplary optical replicator 550 in accordance with the present
systems, devices, and methods. WHUD 500 includes a support
structure (not shown in FIG. 5 to reduce clutter) that may
generally resemble a typical eyeglass frame and a SLP that
comprises a laser module 521 (e.g., an RGB laser module) and at
least one scan mirror 522. In use, laser module 521 produces a
series of light signals 570, each representative of a respective
portion of an image to be displayed to the user. Light signals 570
are directed from laser module 521 to at least one scan mirror
(such as a MEMS-based digital micromirror) 522 that is controllably
variable (e.g., variable in rotational orientation, curvature, or
the like) to reflect the light signals 570 towards select regions
of a holographic combiner 530. Holographic combiner 530 redirects
(e.g., reflects and/or optionally converges) light signals 570
towards the user's eye 590 and into the user's field of view. In
order to increase the effective eyebox of WHUD 500, WHUD 500
further includes an optical replicator 550. In the illustrated
embodiment, optical replicator 550 comprises a set of three partial
reflectors 551, 552, and 553 arranged in series in between scan
mirror 522 and holographic combiner 530 with respect to the optical
paths of light signals 570. A person of skill in the art will be
familiar with various optical device(s) that are partial reflectors
551, 552, and 553, including without limitation: beam-splitters,
half-silvered mirrors, dichroic mirrored prisms, dichroic or
dielectric optical coatings, and the like. Each partial reflector
551, 552, and 553 in optical replicator 550 reflects a respective
portion (e.g., R.sub.i%, where i denotes the specific partial
reflector) of each light signal 570 and transmits any unreflected
portion (i.e., T.sub.i=(1-R.sub.i)%. In this way, optical
replicator 550 effectively replicates each light signal 570 into
three spatially-separated and temporally-parallel instances 571a,
572a, and 573a. The portion of a light signal 570 that is reflected
by each partial reflector 551, 552, and 553 may be designed so that
each resulting instance 571a, 572a, and 573a has substantially the
same brightness. For example, a light signal 570 may initially have
a brightness X. The first partial reflector 551 in optical
replicator 550 may reflect R.sub.551% of light signal 570 as first
instance 571a and transmit T.sub.551% of light signal 570 through
to the second partial reflector 552 in optical replicator 550. The
second partial reflector 550 in optical replicator 550 may reflect
R.sub.552% of the portion of light signal 570 that was transmitted
through the first partial reflector 551 in optical replicator 550
as second instance 572a and transmit T.sub.552% of the portion of
light signal 570 that was transmitted through the first partial
reflector 551. The third partial reflector 553 in optical
replicator 550 may reflect all (i.e., R.sub.553=100%) of the
portion of light signal 570 that was transmitted through the second
partial reflector 552 in optical replicator 550 as instance 573a.
In this case, third partial reflector 553 may not be a "partial"
reflector at all but may be a full mirror or other substantially
compete reflector. In general, uniform brightness across the
replicated instances 571a, 572a, and 573a may be achieved with
R.sub.553>R.sub.552>R.sub.551. Optical replicator 550
includes three partial reflectors 551, 552, and 553 to produce
three instances 571a, 572a, and 573a of each light signal 570,
though in practice any number of partial reflectors may be used to
produce any corresponding number of instances of a light signal. By
replicating light signals 570 as multiple instances 571a, 572a, and
573a by optical replicator 550, each instance 571a, 572a, and 573a
ultimately relays the same portion of the image to a different
region of the user's eye 590, thereby enabling the user to see that
portion of the image from various different eye positions. Because
each one of instances 571a, 572a, and 573a represents the same
portion of an image, the exemplary implementations of holographic
combiner 530 is designed to redirect each one of instances 571a,
572a, and 573a substantially in parallel with one another towards
respective regions of eye 590 (as described in the implementation
in FIG. 2C).
[0086] The partial reflectors 551, 552, and 553 in optical
replicator 550 may be substantially parallel with one another. In
this case, the numerous instances 571a, 572a, and 573a of light
signals 570 emitted from optical replicator 550 may be essentially
parallel with one another and the eyebox of WHUD 500 may be
effectively increased in size by about the total width spanned by
the set of parallel instances 571a, 572a, and 573a of light signal
570. To further expand the eyebox, the partial reflectors 551, 552,
and 553 in optical replicator 550 may be oriented at slight angles
with respect to one another so that the instances 571a, 572a, and
573a of light signals 570 are divergent with respect to one another
when emitted by optical replicator 550. This way, the instances
571a, 572a, and 573a of light signals 570 may span a greater area
and reach wider-spread regions on eye 590.
[0087] FIG. 5 illustrates two different configurations of scan
mirror 522 (a first configuration represented by a solid line and a
second configuration represented by a dotted line), respectively
corresponding to two different light signals 570a and 570b emitted
by laser module 521. After passing through optical replicator 550,
the first, solid-line configuration of scan mirror 522 results in
three instances 571a, 572a, and 573a (also represented by solid
lines) of a first light signal 570a impingent on three points on
holographic combiner 530. Each of the three instances 571a, 572a,
and 573a of first light signal 570a corresponds to a respective
replicated instance of a portion of an image represented by first
light signal 570a. Accordingly, each of three instances 571a, 572a,
and 573a is redirected by holographic combiner 530 spatially in
parallel with one another towards respective spatially-separated
exit pupil 581, 582, and 583 at eye 590 (similar to the exemplary
implementation of FIG. 2C). The second, dotted-line configuration
of scan mirror 522 results in three instances 571b, 572b, and 573b
(also represented by dotted lines) of a second light signal 570b
also impingent on three points on holographic combiner 530. Each of
the three instances 571b, 572b, and 573b of second light signal
570b corresponds to a respective replicated instance of a portion
of an image represented by second light signal 570b. Accordingly,
each of three instances 571b, 572b, and 573b is redirected by
holographic combiner 530 spatially in parallel with one another
towards respective spatially-separated exit pupil 581, 582, and 583
at eye 590. Because first light signal 570a and second light signal
570b each represents a different portion of an image, instances
571a, 572a, and 573a are redirected by holographic combiner 530
towards eye 590 all at a different angle from instances 571b, 572b,
and 573b. Holographic combiner 530 converges: first instance 571a
of first light signal 570a and first instance 571b of second light
signal 570b to a first exit pupil 581, second instance 572a of
first light signal 570a and second instance 572b of second light
signal 570b to a second exit pupil 582, and third instance 573a of
first light signal 570a and third instance 573b of second light
signal 570b to a third exit pupil 583.
[0088] Optical replicator 550 makes use of three partial reflectors
551, 552, and 553 in order to produce three instances 571a, 572a,
and 573a of a light signal 570a directed towards holographic
combiner 530 at respectively different angles and/or from
respectively different virtual positions for scan mirror 522 and/or
laser module 521. However, partial reflectors 551, 552, and 553 are
used in optical replicator 550 in the implementation of FIG. 5 for
exemplary purposes only and, in accordance with the present
systems, devices, and methods other systems, devices, structures,
methods, and/or techniques of replicating light signals 570 may be
employed in optical replicator 550. In some implementations, the
effect or function of an optical replicator 550 may be built into
and realized by a holographic combiner 530. That is, some
architectures of a WHUD may exclude discrete optical replicator 550
and instead achieve such replication upon redirection of light
signals 570 from holographic combiner 530. For example, holographic
combiner 530 may comprise a first hologram carried by a first layer
of holographic material that reflects a first portion R.sub.1 of an
impingent light signal and transmits the remaining portion
T.sub.1=1-R.sub.1, a second hologram carried by a second layer of
holographic material that reflects a second portion R.sub.2 of the
portion of the light signal that was transmitted through the first
layer of holographic material and transmits the remaining portion
T.sub.2=1-R.sub.2, and so on. In order to spread the resulting
copies or instances of the light signal out further than the small
distance between layers of the holographic combiner 530 would
otherwise allow, refraction between successive layers in the
holographic combiner 530 may be employed (e.g., by using different
materials with respective refractive indices for successively
adjacent layers). Alternatively, a holographic combiner 530 may
employ a single layer that is designed to produce multiple
diffraction orders upon reflection of a light signal therefrom,
with each diffraction order corresponding to a respective instance
of the reflected light signal.
[0089] In addition to various WHUD systems and devices that provide
eyebox expansion by exit pupil replication, the various embodiments
described herein also include methods of expanding the eyebox of a
WHUD by exit pupil replication.
[0090] FIG. 6 is a flow-diagram showing a method 600 of operating a
WHUD in accordance with the present systems, devices, and methods.
The WHUD may be substantially similar to WHUD 100, WHUD 200, or
WHUD 300 (as appropriate based on the descriptions of the specific
acts that follow) and generally includes a SLP, an optical
replicator, and a holographic combiner. Method 600 includes three
acts 601, 602, and 603, though those of skill in the art will
appreciate that in alternative embodiments certain acts may be
omitted and/or additional acts may be added. Those of skill in the
art will also appreciate that the illustrated order of the acts is
shown for exemplary purposes only and may change in alternative
embodiments. For the purpose of method 600, the term "user" refers
to a person that is wearing the WHUD.
[0091] At 601, an SLP of the WHUD generates a first light signal.
The first light signal may represent a complete first image or a
portion of a first image. For example, the first light signal may
represent one or more pixel(s) of an image.
[0092] At 602, the optical replicator redirects respective ones of
N instances of the first light signal towards the holographic
combiner, where N is an integer greater than 1. Generally, in
between acts 601 and 602 the optical replicator may receive the
first light signal from the SLP and replicate (e.g., optically
split, furcate, branch, divide, multiply, or otherwise replicate)
the first light signal into the N instances of the first light
signal. When the first light signal represents an image comprising
at least two pixels, the optical replicator may redirect N
respective instances of the image towards the holographic combiner
at 602. When the first light signal represents one or more pixel(s)
of an image, the optical replicator may redirect N instances of the
one or more pixel(s) of the image towards the holographic combiner
at 602. As described previously, the optical replicator may
redirect respective ones of N instances of the first light signal
towards the holographic combiner effectively from respective ones
of N spatially-separated virtual positions for the SLP.
[0093] At 603, the holographic combiner redirects each instance of
the first light signal received from the optical replicator towards
the eye of the user. As described in more detail later on, one or
more instances of the first light signal may be selectively blocked
by a controllable shutter and therefore may not be received from
the optical replicator by the holographic combiner. Depending on
the specific implementation, the holographic combiner may redirect
each instance of the first light signal received from the optical
replicator spatially in parallel with one another towards the eye
of the user. The holographic combiner may converge each instance of
the first light signal received from the optical replicator towards
a respective exit pupil at or proximate the eye of the user.
[0094] In some implementations, the holographic combiner may
include a hologram that redirects instances of the first light
signal towards respective exit pupils at the eye of the user based
on the angle of incidence (at the holographic combiner) of each
instance of the first light signal resulting from the particular
virtual position for the SLP to which the instance of the first
light signal corresponds. Even in such implementations, the
holographic combiner may comprise at least two wavelength
multiplexed holograms to respectively playback for (e.g., perform
the redirecting and/or converging of act 603) at least two
components of the first light signal having different wavelengths,
such as at least two color components of the first light signal.
For example, the SLP may comprise a red laser diode, a green laser
diode, and a blue laser diode and the first light signal may
comprise a red component, a green component, and a blue component.
In this case, the holographic combiner may comprise a red hologram,
a green hologram, and a blue hologram and: the red hologram may
converge a respective red component of each instance of the first
light signal that is received from the optical replicator to a
respective exit pupil at or proximate the eye of the user, the
green hologram may converge a respective green component of each
instance of the first light signal that is received from the
optical replicator to a respective exit pupil at or proximate the
eye of the user, and the blue hologram may converge a respective
blue component of each instance of the first light signal that is
received from the optical replicator to a respective exit pupil at
or proximate the eye of the user.
[0095] In some implementations, the holographic combiner may
include at least two multiplexed holograms and each hologram may
converge a respective instance of the first light signal that is
received from the optical replicator to a respective exit pupil at
or proximate the eye of the user. Continuing on the example above,
the holographic combiner may include at least two angle-multiplexed
red holograms, at least two angle-multiplexed green holograms, and
at least two angle-multiplexed blue holograms. In this case, a
respective angle-multiplexed red hologram may converge a respective
red component of each instance of the first light signal that is
received from the optical replicator to a respective exit pupil at
or proximate the eye of the user, a respective angle-multiplexed
green hologram may converge a respective green component of each
instance of the first light signal that is received from the
optical replicator to a respective exit pupil at or proximate the
eye of the user, and a respective angle-multiplexed blue hologram
may converge a respective blue component of each instance of the
first light signal that is received from the optical replicator to
a respective exit pupil at or proximate the eye of the user.
[0096] Method 600 may be extended in various ways. For example, the
SLP may generate at least a second light signal (e.g.,
corresponding to at least a second image, or at least a second
pixel of the first image, or at least a second set of pixels of the
first image), the optical replicator may redirect respective ones
of N instances of the at least a second light signal towards the
holographic combiner, and the holographic combiner may converge
each instance of the at least a second light signal that is
received from the optical replicator to a respective exit pupil at
or proximate the eye of the user. Similarly, the SLP may generate
light signals corresponding to a sweep of the total scan range
.theta. of the SLP, the optical replicator may receive the total
scan range .theta. of the SLP and redirect respective ones of N
instances of the total scan range .theta. of the SLP towards the
holographic combiner, and the holographic combiner may converge
each instance of the total scan range .theta. of the SLP that is
received from the optical replicator to a respective exit pupil at
or proximate the eye of the user.
[0097] Furthermore, as previously described, the WHUD may include
an eye tracker and at least one controllable shutter
communicatively coupled to (either directly or through one or more
other devices such as a processor and/or memory) the eye tracker.
In this case, the eye tracker may determine the gaze direction
(e.g., pupil position) of the eye of the user and the at least one
controllable shutter may selectively block all but at least one of
the N instances of the light signal redirected towards the
holographic combiner from the optical replicator. For the at least
one of the N instances of the first light signal that is not
blocked by the at least one controllable shutter (i.e., the
"unblocked instance"), the holographic combiner may redirect the
unblocked instance of the first light signal towards a region of
the eye of the user that contains the pupil of the eye of the user
based on the gaze direction of the eye of the user determined by
the eye tracker.
[0098] In accordance with the present systems, devices, and
methods, the eyebox of a retina-scanning projector may be expanded
by replication of one or more exit pupils. In this approach, a
given exit pupil may have a defined size that is about equal to or
smaller than the diameter of the eye's pupil, such as about 4 mm or
less (e.g., about 2 mm), so that all light from an image enters the
eye when the exit pupil impinges on (e.g., e.g., aligns with or
overlies) the user's (physical) pupil. However, when the user moves
their eye, alignment between the exit pupil and the user's pupil
may be lost and the projected image may disappear from the user's
field of view. Thus, in the "eyebox expansion through exit pupil
replication" approaches described herein, multiple exit pupils may
be projected and tiled over the user's eye so that at least one
exit pupil aligns with the user's eye for multiple, many, most, or
all eye positions.
[0099] Throughout this specification and the appended claims, the
term "about" is sometimes used in relation to specific values or
quantities. For example, fast-convergence within "about 2 cm."
Unless the specific context requires otherwise, the term about
generally means.+-.15%.
[0100] The "optical replicator" described herein is an optical
device. A non-limiting example of an optical replicator comprising
an arrangement of partial reflectors is illustrated in (and
described with reference to) FIG. 5; however, the present systems,
devices, and methods are not intended to be limited to the
exemplary implementation of an optical replicator from FIG. 5. An
optical replicator as described herein may comprise any number
and/or arrangement of beam-splitters, prisms, half-silvered
surfaces, dichroics, dielectric coatings, and/or any other optical
device(s) that a person of skill in the art would employ to
optically replicate the light signal or image as described herein.
A person of skill in the art will appreciate that the optical
replication described herein may be accomplished using a wide range
of different optical device(s), individually or in combination,
depending on the requirements of the specific implementation.
Accordingly, the present systems, devices, and methods are
representative of implementations in which an optical device or
arrangement of optical devices optically replicates a light signal
or image as described herein.
[0101] 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 light
source(s) other than a SLP. For example, in some implementations
the SLP described herein may be replaced by another light source,
such as a light source comprising one or more light-emitting diodes
("LEDs"), one or more organic LEDs ("OLEDs"), one or more digital
light processors ("DLPs"). Such non-laser implementations may
advantageously employ additional optics to collimate, focus, and/or
otherwise direct projected light signals. Unless the specific
context requires otherwise, a person of skill in the art will
appreciate that references to a "SLP" throughout the present
systems, devices, and methods are representative and that other
light sources (combined with other optics, as necessary) may be
applied or adapted for application to serve the same general
purpose as the SLPs described herein.
[0102] 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 serves
substantially the same general purpose, 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 representative and that other transparent combiners
(combined with other optics, as necessary) may be applied or
adapted for application to serve the same general purpose as the
holographic combiners described herein.
[0103] 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.
[0104] 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.
[0105] 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.
[0106] In some implementations, the scan range of the projector can
be actively changed to increase resolution in the direction the eye
is looking or in the occupied exit pupil. Such is an example of
heterogeneous image resolution as described in U.S. Provisional
Patent Application Ser. No. 62/134,347.
[0107] 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.
[0108] In some implementations, one or more optical fiber(s) may be
used to guide light signals along some of the paths illustrated
herein.
[0109] The various implementations described herein may,
optionally, employ the systems, devices, and methods for preventing
eyebox degradation described in U.S. Provisional Patent Application
Ser. No. 62/288,947.
[0110] 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.
[0111] 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).
[0112] The WHUDs described herein may receive and respond to
commands from the user in one or more of a variety of ways,
including without limitation: voice commands through a microphone;
touch commands through buttons, switches, or a touch sensitive
surface; and/or gesture-based commands through gesture detection
systems as described in, for example, U.S. Non-Provisional patent
application Ser. No. 14/155,087, U.S. Non-Provisional patent
application Ser. No. 14/155,107, PCT Patent Application
PCT/US2014/057029, and/or U.S. Provisional Patent Application Ser.
No. 62/236,060, all of which are incorporated by reference herein
in their entirety.
[0113] The various implementations of WHUDs described herein may
include any or all of the technologies described in U.S.
Provisional Patent Application Ser. No. 62/117,316, U.S.
Provisional Patent Application Ser. No. 62/156,736, and/or U.S.
Provisional Patent Application Ser. No. 62/242,844.
[0114] 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.
[0115] 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.
[0116] 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.
[0117] 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.
[0118] 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.
[0119] 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.
[0120] 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.
Non-Provisional patent application Ser. No. 15/046,234, U.S.
Provisional Patent Application Ser. No. 62/214,600, U.S.
Provisional Patent Application Ser. No. 62/268,892, U.S.
Provisional Patent Application Ser. No. 62/167,767, U.S.
Provisional Patent Application Ser. No. 62/271,135, U.S.
Provisional Patent Application Ser. No. 62/245,792, U.S.
Provisional Patent Application Ser. No. 62/281,041, U.S.
Provisional Patent Application Ser. No. 62/134,347, U.S.
Provisional Patent Application Ser. No. 62/288,947, U.S.
Non-Provisional patent application Ser. No. 14/155,087, U.S.
Non-Provisional patent application Ser. No. 14/155,107, PCT Patent
Application PCT/US2014/057029, U.S. Provisional Patent Application
Ser. No. 62/236,060, U.S. Provisional Patent Application Ser. No.
62/117,316, U.S. Provisional Patent Application Ser. No.
62/156,736, and U.S. Provisional Patent Application Ser. No.
62/242,844, 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.
[0121] 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.
* * * * *