U.S. patent application number 14/194548 was filed with the patent office on 2015-07-23 for optical configurations for head worn computing.
The applicant listed for this patent is Osterhout Group, Inc.. Invention is credited to John N. Border, John D. Haddick.
Application Number | 20150205122 14/194548 |
Document ID | / |
Family ID | 53544639 |
Filed Date | 2015-07-23 |
United States Patent
Application |
20150205122 |
Kind Code |
A1 |
Border; John N. ; et
al. |
July 23, 2015 |
OPTICAL CONFIGURATIONS FOR HEAD WORN COMPUTING
Abstract
Aspects of the present invention relate to optical systems in
head worn computing.
Inventors: |
Border; John N.; (Eaton,
NH) ; Haddick; John D.; (San Rafael, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Osterhout Group, Inc. |
San Francisco |
CA |
US |
|
|
Family ID: |
53544639 |
Appl. No.: |
14/194548 |
Filed: |
February 28, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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14160377 |
Jan 21, 2014 |
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14194548 |
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Current U.S.
Class: |
359/13 ;
359/292 |
Current CPC
Class: |
G02B 27/0172 20130101;
G06F 3/013 20130101; G02B 26/0816 20130101; G02B 27/017 20130101;
H04N 5/23222 20130101; G02B 2027/0138 20130101; G02B 27/286
20130101; G02B 2027/014 20130101; G02B 27/0103 20130101; G02B
2027/0178 20130101; G02B 2027/0174 20130101; G02B 5/003 20130101;
G02B 27/0093 20130101; H04N 2213/008 20130101; G02B 2027/0118
20130101; G02B 5/3083 20130101 |
International
Class: |
G02B 27/01 20060101
G02B027/01; G02B 26/08 20060101 G02B026/08 |
Claims
1. A head-worn computer, comprising: a. an image light production
facility including a platform including a plurality of
multi-positional mirrors; b. a lighting facility positioned along a
first side of the platform and adapted to produce a cone of
illumination light into a solid optic along an optical axis
directed away from a front surface of the platform and towards a
substantially flat surface of the solid optic that reflects the
illumination light such that the front surface of the platform is
substantially uniformly illuminated; c. wherein each of the
multi-positional mirrors has an "on" state to reflect a portion of
the illumination light along a first optical axis that is on-line
with an eye of a person wearing the head-worn computer thereby
providing bright image pixels and an "off" state to reflect a
portion of illumination light along a second optical axis off-line
with an eye of a person wearing the head-worn computer thereby
providing dark image pixels; and d. an angled surface in the solid
optic that transmits bright image pixel light while reflecting dark
image pixel light , such that light from the "off" state mirrors is
redirected toward a second side of the platform, thereby
establishing a vertically compact system.
2. The head-worn computer of claim 1, further comprising: a. A
holographic mirror in-line with the optical axis in-line with the
eye of the person wearing the head-worn computer and positioned on
an angle with respect to a front surface of the platform to reflect
the image light directly, without further reflections, towards the
eye of the person wearing the head-worn computer.
3. The head-worn computer of claim 2, wherein the angle is greater
than 45 degrees.
4. The head-worn computer of claim 1, wherein the holographic
mirror is adapted to reflect a plurality of visible bandwidths of
light and transmit substantially all other visible bandwidths other
than the plurality of reflected visible bandwidths of light.
5. The head-worn computer of claim 4, wherein the holographic
mirror transmits a majority of surrounding environment light
incident on the holographic mirror.
6. The head-worn computer of claim 4, wherein the lighting facility
produces a narrow bandwidth of light with a quantum dot
illumination facility.
7. The head-worn computer of claim 4, wherein the lighting facility
produces a narrow bandwidth of light with a light emitting diode
lighting facility.
8. The head-worn computer of claim 4, wherein the lighting facility
produces a diffuse cone of light with a backlit illumination
facility.
9. The head-worn computer of claim 1, further comprising: b. A
notch mirror in-line with the optical axis in-line with the eye of
the person wearing the head-worn computer and positioned on an
angle with respect to a front surface of the platform to reflect
the image light directly towards the eye of the person wearing the
head-worn computer.
10. The head-worn computer of claim 1, further comprising an eye
imaging camera positioned to image the eye of the person wearing
the head-worn computer by capturing light reflected off a subset of
the plurality of mirrors wherein the subset of the plurality of
mirrors are in a second state.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of priority to and is a
continuation of the following U.S. patent applications, each of
which is hereby incorporated by reference in its entirety:
[0002] U.S. non-provisional application Ser. No. 14/160,377,
entitled OPTICAL CONFIGURATIONS FOR HEAD WORN COMPUTING, filed Jan.
21, 2014
BACKGROUND
[0003] 1. Field of the Invention
[0004] This invention relates to head worn computing. More
particularly, this invention relates to optical systems used in
head worn computing.
[0005] 2 Description of Related Art
[0006] Wearable computing systems have been developed and are
beginning to be commercialized. Many problems persist in the
wearable computing field that need to be resolved to make them meet
the demands of the market.
SUMMARY
[0007] Aspects of the present invention relate to optical systems
in head worn computing. Aspects relate to the management of "off"
pixel light. Aspects relate to absorbing "off" pixel light. Aspects
relate to improved see-through transparency of the HWC optical path
to the surrounding environment. Aspects relate to improved image
contrast, brightness, sharpness and other image quality through the
management of stray light. Aspects relate to eye imaging through
"off" pixels. Aspects relate to security compliance and security
compliance tracking through eye imaging. Aspects relate to guest
access of a HWC through eye imaging. Aspects relate to providing
system and software access based on eye imaging.
[0008] These and other systems, methods, objects, features, and
advantages of the present invention will be apparent to those
skilled in the art from the following detailed description of the
preferred embodiment and the drawings. All documents mentioned
herein are hereby incorporated in their entirety by reference.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Embodiments are described with reference to the following
Figures. The same numbers may be used throughout to reference like
features and components that are shown in the Figures:
[0010] FIG. 1 illustrates a head worn computing system in
accordance with the principles of the present invention.
[0011] FIG. 2 illustrates a head worn computing system with optical
system in accordance with the principles of the present
invention.
[0012] FIG. 3a illustrates a large optical arrangement that is not
well suited for a compact HWC.
[0013] FIG. 3b illustrates an upper optical module in accordance
with the principles of the present invention.
[0014] FIG. 4 illustrates an upper optical module in accordance
with the principles of the present invention.
[0015] FIG. 4a illustrates an upper optical module in accordance
with the principles of the present invention.
[0016] FIG. 5 illustrates an upper optical module in accordance
with the principles of the present invention.
[0017] FIG. 5a illustrates an upper optical module in accordance
with the principles of the present invention.
[0018] FIG. 6 illustrates upper and lower optical modules in
accordance with the principles of the present invention.
[0019] FIG. 7 illustrates angles of combiner elements in accordance
with the principles of the present invention.
[0020] FIG. 8 illustrates upper and lower optical modules in
accordance with the principles of the present invention.
[0021] FIG. 9 illustrates an eye imaging system in accordance with
the principles of the present invention.
[0022] FIG. 10 illustrates a light source in accordance with the
principles of the present invention.
[0023] FIG. 10a illustrates a back lighting system in accordance
with the principles of the present invention.
[0024] FIG. 10b illustrates a back lighting system in accordance
with the principles of the present invention.
[0025] FIG. 11a to 11d illustrate a light source and filter in
accordance with the principles of the present invention.
[0026] FIGS. 12a to 12c illustrate a light source and quantum dot
system in accordance with the principles of the present
invention.
[0027] While the invention has been described in connection with
certain preferred embodiments, other embodiments would be
understood by one of ordinary skill in the art and are encompassed
herein.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
[0028] Aspects of the present invention relate to head-worn
computing ("HWC") systems. HWC involves, in some instances, a
system that mimics the appearance of head-worn glasses or
sunglasses. The glasses may be a fully developed computing
platform, such as including computer displays presented in each of
the lenses of the glasses to the eyes of the user. In embodiments,
the lenses and displays may be configured to allow a person wearing
the glasses to see the environment through the lenses while also
seeing, simultaneously, digital imagery, which forms an overlaid
image that is perceived by the person as a digitally augmented
image of the environment, or augmented reality ("AR").
[0029] HWC involves more than just placing a computing system on a
person's head. The system may need to be designed as a lightweight,
compact and fully functional computer display, such as wherein the
computer display includes a high resolution digital display that
provides a high level of emersion comprised of the displayed
digital content and the see-through view of the environmental
surroundings. User interfaces and control systems suited to the HWC
device may be required that are unlike those used for a more
conventional computer such as a laptop. For the HWC and associated
systems to be most effective, the glasses may be equipped with
sensors to determine environmental conditions, geographic location,
relative positioning to other points of interest, objects
identified by imaging and movement by the user or other users in a
connected group, and the like. The HWC may then change the mode of
operation to match the conditions, location, positioning,
movements, and the like, in a method generally referred to as a
contextually aware HWC. The glasses also may need to be connected,
wirelessly or otherwise, to other systems either locally or through
a network. Controlling the glasses may be achieved through the use
of an external device, automatically through contextually gathered
information, through user gestures captured by the glasses sensors,
and the like. Each technique may be further refined depending on
the software application being used in the glasses. The glasses may
further be used to control or coordinate with external devices that
are associated with the glasses.
[0030] Referring to FIG. 1, an overview of the HWC system 100 is
presented. As shown, the HWC system 100 comprises a HWC 102, which
in this instance is configured as glasses to be worn on the head
with sensors such that the HWC 102 is aware of the objects and
conditions in the environment 114. In this instance, the HWC 102
also receives and interprets control inputs such as gestures and
movements 116. The HWC 102 may communicate with external user
interfaces 104. The external user interfaces 104 may provide a
physical user interface to take control instructions from a user of
the HWC 102 and the external user interfaces 104 and the HWC 102
may communicate bi-directionally to affect the user's command and
provide feedback to the external device 108. The HWC 102 may also
communicate bi-directionally with externally controlled or
coordinated local devices 108. For example, an external user
interface 104 may be used in connection with the HWC 102 to control
an externally controlled or coordinated local device 108. The
externally controlled or coordinated local device 108 may provide
feedback to the HWC 102 and a customized GUI may be presented in
the HWC 102 based on the type of device or specifically identified
device 108. The HWC 102 may also interact with remote devices and
information sources 112 through a network connection 110. Again,
the external user interface 104 may be used in connection with the
HWC 102 to control or otherwise interact with any of the remote
devices 108 and information sources 112 in a similar way as when
the external user interfaces 104 are used to control or otherwise
interact with the externally controlled or coordinated local
devices 108. Similarly, HWC 102 may interpret gestures 116 (e.g
captured from forward, downward, upward, rearward facing sensors
such as camera(s), range finders, IR sensors, etc.) or
environmental conditions sensed in the environment 114 to control
either local or remote devices 108 or 112.
[0031] We will now describe each of the main elements depicted on
FIG. 1 in more detail; however, these descriptions are intended to
provide general guidance and should not be construed as limiting.
Additional description of each element may also be further
described herein.
[0032] The HWC 102 is a computing platform intended to be worn on a
person's head. The HWC 102 may take many different forms to fit
many different functional requirements. In some situations, the HWC
102 will be designed in the form of conventional glasses. The
glasses may or may not have active computer graphics displays. In
situations where the HWC 102 has integrated computer displays the
displays may be configured as see-through displays such that the
digital imagery can be overlaid with respect to the user's view of
the environment 114. There are a number of see-through optical
designs that may be used, including ones that have a reflective
display (e.g. LCoS, DLP), emissive displays (e.g. OLED, LED),
hologram, TIR waveguides, and the like. In addition, the optical
configuration may be monocular or binocular. It may also include
vision corrective optical components. In embodiments, the optics
may be packaged as contact lenses. In other embodiments, the HWC
102 may be in the form of a helmet with a see-through shield,
sunglasses, safety glasses, goggles, a mask, fire helmet with
see-through shield, police helmet with see through shield, military
helmet with see-through shield, utility form customized to a
certain work task (e.g. inventory control, logistics, repair,
maintenance, etc.), and the like.
[0033] The HWC 102 may also have a number of integrated computing
facilities, such as an integrated processor, integrated power
management, communication structures (e.g. cell net, WiFi,
Bluetooth, local area connections, mesh connections, remote
connections (e.g. client server, etc.)), and the like. The HWC 102
may also have a number of positional awareness sensors, such as
GPS, electronic compass, altimeter, tilt sensor, IMU, and the like.
It may also have other sensors such as a camera, rangefinder,
hyper-spectral camera, Geiger counter, microphone, spectral
illumination detector, temperature sensor, chemical sensor,
biologic sensor, moisture sensor, ultrasonic sensor, and the
like.
[0034] The HWC 102 may also have integrated control technologies.
The integrated control technologies may be contextual based
control, passive control, active control, user control, and the
like. For example, the HWC 102 may have an integrated sensor (e.g.
camera) that captures user hand or body gestures 116 such that the
integrated processing system can interpret the gestures and
generate control commands for the HWC 102. In another example, the
HWC 102 may have sensors that detect movement (e.g. a nod, head
shake, and the like) including accelerometers, gyros and other
inertial measurements, where the integrated processor may interpret
the movement and generate a control command in response. The HWC
102 may also automatically control itself based on measured or
perceived environmental conditions. For example, if it is bright in
the environment the HWC 102 may increase the brightness or contrast
of the displayed image. In embodiments, the integrated control
technologies may be mounted on the HWC 102 such that a user can
interact with it directly. For example, the HWC 102 may have a
button(s), touch capacitive interface, and the like.
[0035] As described herein, the HWC 102 may be in communication
with external user interfaces 104. The external user interfaces may
come in many different forms. For example, a cell phone screen may
be adapted to take user input for control of an aspect of the HWC
102. The external user interface may be a dedicated UI, such as a
keyboard, touch surface, button(s), joy stick, and the like. In
embodiments, the external controller may be integrated into another
device such as a ring, watch, bike, car, and the like. In each
case, the external user interface 104 may include sensors (e.g.
IMU, accelerometers, compass, altimeter, and the like) to provide
additional input for controlling the HWD 104.
[0036] As described herein, the HWC 102 may control or coordinate
with other local devices 108. The external devices 108 may be an
audio device, visual device, vehicle, cell phone, computer, and the
like. For instance, the local external device 108 may be another
HWC 102, where information may then be exchanged between the
separate HWCs 108.
[0037] Similar to the way the HWC 102 may control or coordinate
with local devices 106, the HWC 102 may control or coordinate with
remote devices 112, such as the HWC 102 communicating with the
remote devices 112 through a network 110. Again, the form of the
remote device 112 may have many forms. Included in these forms is
another HWC 102. For example, each HWC 102 may communicate its GPS
position such that all the HWCs 102 know where all of HWC 102 are
located.
[0038] DLP Optical Configurations
[0039] FIG. 2 illustrates a HWC 102 with an optical system that
includes an upper optical module 202 and a lower optical module
204. While the upper and lower optical modules 202 and 204 will
generally be described as separate modules, it should be understood
that this is illustrative only and the present invention includes
other physical configurations, such as that when the two modules
are combined into a single module or where the elements making up
the two modules are configured into more than two modules. In
embodiments, the upper module 202 includes a computer controlled
display (e.g. LCoS, DLP, OLED, etc.) and image light delivery
optics. In embodiments, the lower module includes eye delivery
optics that are configured to receive the upper module's image
light and deliver the image light to the eye of a wearer of the
HWC. In FIG. 2, it should be noted that while the upper and lower
optical modules 202 and 204 are illustrated in one side of the HWC
such that image light can be delivered to one eye of the wearer,
that it is envisioned by the present invention that embodiments
will contain two image light delivery systems, one for each
eye.
[0040] FIG. 3b illustrates an upper optical module 202 in
accordance with the principles of the present invention. In this
embodiment, the upper optical module 202 includes a DLP computer
operated display 304 which includes pixels comprised of rotatable
mirrors, polarized light source 302, 1/4 wave retarder film 308,
reflective polarizer 310 and a field lens 312. The polarized light
source 302 provides substantially uniform light that is generally
directed towards the reflective polarizer 310. The reflective
polarizer reflects light of one polarization state (e.g. S
polarized light) and transmits light of the other polarization
state (e.g. P polarized light). The polarized light source 302 and
the reflective polarizer 310 are oriented so that the polarized
light from the polarized light source 302 reflected generally
towards the DLP 304. The light then passes through the 1/4 wave
film 308 once before illuminating the pixels of the DLP 304 and
then again after being reflected by the pixels of the DLP 304. In
passing through the 1/4 wave film 308 twice, the light is converted
from one polarization state to the other polarization state (e.g.
the light is converted from S to P polarized light). The light then
passes through the reflective polarizer 310. In the event that the
DLP pixel(s) are in the "on" state (i.e. the mirrors are positioned
to reflect light back towards the field lens 312, the "on" pixels
reflect the light generally along the optical axis and into the
field lens 312. This light that is reflected by "on" pixels and
which is directed generally along the optical axis of the field
lens 312 will be referred to as image light 316. The image light
316 then passes through the field lens to be used by a lower
optical module 204.
[0041] The light that is provided by the polarized light source
302, which is subsequently reflected by the reflective polarizer
310 before it reflects from the DLP 304, will generally be referred
to as illumination light. The light that is reflected by the "off"
pixels of the DLP 304 is reflected at a different angle than the
light reflected by the `on" pixels, so that the light from the
"off" pixels is generally directed away from the optical axis of
the field lens 312 and toward the side of the upper optical module
202 as shown in FIG. 3.. The light that is reflected by the "off"
pixels of the DLP 304 will be referred to as dark state light
314.
[0042] The DLP 304 operates as a computer controlled display and is
generally thought of as a MEMs device. The DLP pixels are comprised
of small mirrors that can be directed. The mirrors generally flip
from one angle to another angle. The two angles are generally
referred to as states. When light is used to illuminate the DLP the
mirrors will reflect the light in a direction depending on the
state. In embodiments herein, we generally refer to the two states
as "on" and "off," which is intended to depict the condition of a
display pixel. "On" pixels will be seen by a viewer of the display
as emitting light because the light is directed along the optical
axis and into the field lens and the associated remainder of the
display system. "Off" pixels will be seen by a viewer of the
display as not emitting light because the light from these pixels
is directed to the side of the optical housing and into a light
dump where the light is absorbed. The pattern of "on" and "off"
pixels produces image light that is perceived by a viewer of the
display as a computer generated image. Full color images can be
presented to a user by sequentially providing illumination light
with complimentary colors such as red, green and blue. Where the
sequence is presented in a recurring cycle that is faster than the
user can perceive as separate images and as a result the user
perceives a full color image comprised of the sum of the sequential
images. Bright pixels in the image are provided by pixels that
remain in the "on" state for the entire time of the cycle, while
dimmer pixels in the image are provided by pixels that switch
between the "on" state and "off" state within the time of the
cycle.
[0043] FIG. 3a shows an illustration of a system for a DLP 304 in
which the unpolarized light source 350 is pointed directly at the
DLP 304. In this case, the angle required for the illumination
light is such that the field lens 352 must be positioned
substantially distant from the DLP 304 to avoid the illumination
light from being clipped by the field lens 352. The large distance
between the field lens 352 and the DLP 304 along with the straight
path of the dark state light 352, means that the light trap for the
dark state light 352 is located at a substantial distance from the
DLP. For these reasons, this configuration is larger in size
compared to the upper optics module 202 of the preferred
embodiments.
[0044] The configuration illustrated in FIG. 3b can be lightweight
and compact such that it fits into a portion of a HWC. For example,
the upper modules 202 illustrated herein can be physically adapted
to mount in an upper frame of a HWC such that the image light can
be directed into a lower optical module 204 for presentation of
digital content to a wearer's eye. The package of components that
combine to generate the image light (i.e. the polarized light
source 302, DLP 304, reflective polarizer 310 and 1/4 wave film
308) is very light and is compact. The height of the system,
excluding the field lens, may be less than 8 mm. The width (i.e.
from front to back) may be less than 8 mm. The weight may be less
than 2 grams. The compactness of this upper optical module 202
allows for a compact mechanical design of the HWC and the light
weight nature of these embodiments help make the HWC lightweight to
provide for a HWC that is comfortable for a wearer of the HWC.
[0045] The configuration illustrated in FIG. 3b can produce sharp
contrast, high brightness and deep blacks, especially when compared
to LCD or LCoS displays used in HWC. The "on" and "off" states of
the DLP provide for a strong differentiator in the light reflection
path representing an "on" pixel and an "off" pixel. As will be
discussed in more detail below, the dark state light from the "off"
pixel reflections can be managed to reduce stray light in the
display system to produce images with high contrast.
[0046] FIG. 4 illustrates another embodiment of an upper optical
module 202 in accordance with the principles of the present
invention. This embodiment includes a light source 404, but in this
case, the light source can provide unpolarized illumination light.
The illumination light from the light source 404 is directed into a
TIR wedge 418 such that the illumination light is incident on an
internal surface of the TIR wedge 418 (shown as the angled lower
surface of the TRI wedge 418 in FIG. 4) at an angle that is beyond
the critical angle as defined by Eqn 1.
Critical angle=arc-sin(1/n) Eqn 1
[0047] Where the critical angle is the angle beyond which the
illumination light is reflected from the internal surface when the
internal surface comprises an interface from a solid with a higher
refractive index to air with a refractive index of 1 (e.g. for an
interface of acrylic, with a refractive index of 1.5, to air, the
critical angle is 41.8 degrees; for an interface of polycarbonate,
with a refractive index of 1.59, to air the critical angle is 38.9
degrees). Consequently, the TIR wedge 418 is associated with a thin
air gap 408 along the internal surface to create an interface
between a solid with a higher refractive index and air. By choosing
the angle of the light source 404 relative to the DLP 402 in
correspondence to the angle of the internal surface of the TIR
wedge 418, illumination light is turned toward the DLP 402 at an
angle suitable for providing image light as reflected from
"on"pixels. Wherein, the illumination light is provided to the DLP
402 at approximately twice the angle of the pixel mirrors in the
DLP 402 that are in the "on" state, such that after reflecting from
the pixel mirrors, the image light is directed generally along the
optical axis of the field lens. Depending on the state of the DLP
pixels, the illumination light from "on" pixels may be reflected as
image light 414 which is directed towards a field lens and a lower
optical module 204, while illumination light reflected from "off"
pixels (dark state light) is directed in a separate direction 410,
which may be trapped and not used for the image that is ultimately
presented to the wearer's eye.
[0048] The light trap may be located along the optical axis defined
by the direction 410 and in the side of the housing, with the
function of absorbing the dark state light. To this end, the light
trap may be comprised of an area outside of the cone of image light
from the "on" pixels. The light trap is typically madeup of
materials that absorb light including coatings of black paints or
other light absorbing to prevent light scattering from the dark
state light degrading the image perceived by the user. In addition,
the light trap may be recessed into the wall of the housing or
include masks or guards to block scattered light and prevent the
light trap from being viewed adjacent to the displayed image..
[0049] The embodiment of FIG. 4 also includes a corrective wedge
420 to correct the effect of refraction of the image light 414 as
it exits the TIR wedge 418. By including the corrective wedge 420
and providing a thin air gap 408 (e.g. 25 micron), the image light
from the "on" pixels can be maintained generally in a direction
along the optical axis of the field lens so it passes into the
field lens and the lower optical module 204. As shown in FIG. 4,
the image light from the "on" pixels exits the corrective wedge 420
generally perpendicular to the surface of the corrective wedge 420
while the dark state light exits at an oblique angle. As a result,
the direction of the image light from the "on" pixels is largely
unaffected by refraction as it exits from the surface of rthe
corrective wedge 420. In contrast, the dark state light is
substantially changed in direction by refraction when the dark
state light exits the corrective wedge 420.
[0050] The embodiment illustrated in FIG. 4 has the similar
advantages of those discussed in connection with the embodiment of
FIG. 3b. The dimensions and weight of the upper module 202 depicted
in FIG. 4 may be approximately 8.times.8 mm with a weight of less
than 3 grams. A difference in overall performance between the
configuration illustrated in FIGS. 3b and the configuration
illustrated in FIG. 4 is that the embodiment of FIG. 4 doesn't
require the use of polarized light as supplied by the light source
404. This can be an advantage in some situations as will be
discussed in more detail below (e.g. increased see-through
transparency of the HWC optics from the user's perspective). An
addition advantage of the embodiment of FIG. 4 compared to the
embodiment shown in FIG. 3b is that the dark state light (shown as
DLP off light 410) is directed at a steeper angle away from the
optical axis due to the added refraction encountered when the dark
state light exits the corrective wedge 420. This steeper angle of
the dark state light allows for the light trap to be positioned
closer to the DLP 402 so that the overall size of the upper module
202 can be reduced. The light trap can also be made larger since
the light trap doesn't interfere with the field lens, thereby the
efficiency of the light trap can be increased and as a result,
stray light can be reduced and the contrast of the image perceived
by the user can be increased. FIG. 4a illustrates the embodiment
described in connection with FIG. 4 with the addition of more
details on light angles at the various surfaces.
[0051] FIG. 5 illustrates yet another embodiment of an upper
optical module 202 in accordance with the principles of the present
invention. As with the embodiment shown in FIG. 4, the embodiment
shown in FIG. 5 does not require the use of polarized light. The
optical module 202 depicted in FIG. 5 is similar to that presented
in connection with FIG. 4; however, the embodiment of FIG. 5
includes an off light redirection wedge 502. As can be seen from
the illustration, the off light redirection wedge 502 allows the
image light 414 to continue generally along the optical axis toward
the field lens and into the lower optical module 204 (as
illustrated). However, the off light 504 is redirected
substantially toward the side of the corrective wedge 420 where it
passes into the light trap . This configuration may allow further
height compactness in the HWC because the light trap (not
illustrated) that is intended to absorb the off light 504 can be
positioned laterally adjacent the upper optical module 202 as
opposed to below it. In the embodiment depicted in FIG. 5 there is
a thin air gap between the TIR wedge 418 and the corrective wedge
420 (similar to the embodiment of FIG. 4). There is also a thin air
gap between the corrective wedge 420 and the off light redirection
wedge 502. There may be HWC mechanical configurations that warrant
the positioning of a light trap for the dark state light elsewhere
and the illustration depicted in FIG. 5 should be considered
illustrative of the concept that the off light can be redirected to
create compactness of the overall HWC. FIG. 5a illustrates the
embodiment described in connection with FIG. 5 with the addition of
more details on light angles at the various surfaces.
[0052] FIG. 6 illustrates a combination of an upper optical module
202 with a lower optical module 204. In this embodiment, the image
light projected from the upper optical module 202 may or may not be
polarized. The image light is reflected off a flat combiner element
602 such that it is directed towards the user's eye. Wherein, the
combiner element 602 is a partial mirror that reflects image light
while transmitting a substantial portion of light from the
environment so the user can look through the combiner element and
see the environment surrounding the HWC.
[0053] The combiner 602 may include a holographic pattern, to form
a holographic mirror. If a monochrome image is desired, there may
be a single wavelength reflection design for the holographic
pattern on the surface of the combiner 602. If the intention is to
have multiple colors reflected from the surface of the combiner
602, a multiple wavelength holographic mirror maybe included on the
combiner surface. For example, in a three color embodiment, where
red, green and blue pixels are generated in the image light, the
holographic mirror may be reflective to wavelengths matching the
wavelengths of the red, green and blue light provided by the light
source. This configuration can be used as a wavelength specific
mirror where pre-determined wavelengths of light from the image
light are reflected to the user's eye. This configuration may also
be made such that substantially all other wavelengths in the
visible pass through the combiner element 602 so the user has a
substantially clear view of the surroundings when looking through
the combiner element 602. The transparency between the user's eye
and the surrounding may be approximately 80% when using a combiner
that is a holographic mirror. Wherein holographic mirrors can be
made using lasers to produce interference patterns in the
holographic material of the combiner where the wavelengths of the
lasers correspond to the wavelengths of light that are subsequently
reflected by the holographic mirror.
[0054] In another embodiment, the combiner element 602 may include
a notch mirror comprised of a multilayer coated substrate wherein
the coating is designed to substantially reflect the wavelengths of
light provided by the light source and substantially transmit the
remaining wavelengths in the visible spectrum. For example, in the
case where red, green and blue light is provided by the light
source to enable full color images to be provided to the user, the
notch mirror is a tristimulus notch mirror wherein the multilayer
coating is designed to reflect narrow bands of red, green and blue
light that are matched to the what is provided by the light source
and the remaining visible wavelengths are transmitted to enable a
view of the environment through the combiner. In another example
where monochrome images are provide to the user, the notch mirror
is designed to reflect a narrow band of light that is matched to
the wavelengths of light provided by the light source while
transmitting the remaining visible wavelengths to enable a see-thru
view of the environment. . The combiner 602 with the notch mirror
would operate, from the user's perspective, in a manner similar to
the combiner that includes a holographic pattern on the combiner
element 602. The combiner, with the tristimulus notch mirror, would
reflect the "on" pixels to the eye because of the match between the
reflective wavelengths of the notch mirror and the color of the
image light, and the wearer would be able to see with high clarity
the surroundings. The transparency between the user's eye and the
surrounding may be approximately 80% when using the tristimulus
notch mirror. In addition, the image provided by the upper optical
module 202 with the notch mirror combiner can provide higher
contrast images than the holographic mirror combiner due to less
scattering of the imaging light by the combiner.
[0055] Light can escape through the combiner 602 and may produce
face glow as the light is generally directed downward onto the
cheek of the user. When using a holographic mirror combiner or a
tristimulus notch mirror combiner, the escaping light can be
trapped to avoid face glow. In embodiments, if the image light is
polarized before the combiner, a linear polarizer can be laminated,
or otherwise associated, to the combiner, with the transmission
axis of the polarizer oriented relative to the polarized image
light so that any escaping image light is absorbed by the
polarizer. In embodiments, the image light would be polarized to
provide S polarized light to the combiner for better reflection. As
a result, the linear polarizer on the combiner would be oriented to
absorb S polarized light and pass P polarized light. This provides
the preferred orientation of polarized sunglasses as well.
[0056] If the image light is unpolarized, a microlouvered film such
as a privacy filter can be used to absorb the escaping image light
while providing the user with a see-thru view of the environment.
In this case, the absorbance or transmittance of the microlouvered
film is dependent on the angle of the light,. Where steep angle
light is absorbed and light at less of an angle is transmitted. For
this reason, in an embodiment, the combiner with the microlouver
film is angled at greater than 45 degrees to the optical axis of
the image light (e.g. the combiner can be oriented at 50 degrees so
the image light from the file lens is incident on the combiner at
an oblique angle.
[0057] FIG. 7 illustrates an embodiment of a combiner element 602
at various angles when the combiner element 602 includes a
holographic mirror. Normally, a mirrored surface reflects light at
an angle equal to the angle that the light is incident to the
mirrored surface. Typically this necessitates that the combiner
element be at 45 degrees, 602a, if the light is presented
vertically to the combiner so the light can be reflected
horizontally towards the wearer's eye. In embodiments, the incident
light can be presented at angles other than vertical to enable the
mirror surface to be oriented at other than 45 degrees, but in all
cases wherein a mirrored surface is employed, the incident angle
equals the reflected angle. As a result, increasing the angle of
the combiner 602a requires that the incident image light be
presented to the combiner 602a at a different angle which positions
the upper optical module 202 to the left of the combiner as shown
in FIG. 7. In contrast, a holographic mirror combiner, included in
embodiments, can be made such that light is reflected at a
different angle from the angle that the light is incident onto the
holographic mirrored surface. This allows freedom to select the
angle of the combiner element 602b independent of the angle of the
incident image light and the angle of the light reflected into the
wearer's eye. In embodiments, the angle of the combiner element
602b is greater than 45 degrees (shown in FIG. 7) as this allows a
more laterally compact HWC design. The increased angle of the
combiner element 602b decreases the front to back width of the
lower optical module 204 and may allow for a thinner HWC display
(i.e. the furthest element from the wearer's eye can be closer to
the wearer's face).
[0058] FIG. 8 illustrates another embodiment of a lower optical
module 204. In this embodiment, polarized image light provided by
the upper optical module 202, is directed into the lower optical
module 204. The image light reflects off a polarized mirror 804 and
is directed to a focusing partially reflective mirror 802, which is
adapted to reflect the polarized light. An optical element such as
a 1/4 wave film located between the polarized mirror 804 and the
partially reflective mirror 802, is used to change the polarization
state of the image light such that the light reflected by the
partially reflective mirror 802 is transmitted by the polarized
mirror 804 to present image light to the eye of the wearer. The
user can also see through the polarized mirror 804 and the
partially reflective mirror 802 to see the surrounding environment.
As a result, the user perceives a combined image comprised of the
displayed image light overlaid onto the see-thru view of the
environment.
[0059] Another aspect of the present invention relates to eye
imaging. In embodiments, a camera is used in connection with an
upper optical module 202 such that the wearer's eye can be imaged
using pixels in the "off" state on the DLP. FIG. 9 illustrates a
system where the eye imaging camera 802 is mounted and angled such
that the field of view of the eye imaging camera 802 is redirected
toward the wearer's eye by the mirror pixels of the DLP 402 that
are in the "off" state. In this way, the eye imaging camera 802 can
be used to image the wearer's eye along the same optical axis as
the displayed image that is presented to the wearer. Wherein, image
light that is presented to the wearer's eye illuminates the
wearer's eye so that the eye can be imaged by the eye imaging
camera 802. In the process, the light reflected by the eye passes
back though the optical train of the lower optical module 204 and a
portion of the upper optical module to where the light is reflected
by the "off" pixels of the DLP 402 toward the eye imaging camera
802.
[0060] In embodiments, the eye imaging camera may image the
wearer's eye at a moment in time where there are enough "off"
pixels to achieve the required eye image resolution. In another
embodiment, the eye imaging camera collects eye image information
from "off" pixels over time and forms a time lapsed image. In
another embodiment, a modified image is presented to the user
wherein enough "off" state pixels are included that the camera can
obtain the desired resolution and brightness for imaging the
wearer's eye and the eye image capture is synchronized with the
presentation of the modified image.
[0061] The eye imaging system may be used for security systems. The
HWC may not allow access to the HWC or other system if the eye is
not recognized (e.g. through eye characteristics including retina
or iris characteristics, etc.). The HWC may be used to provide
constant security access in some embodiments. For example, the eye
security confirmation may be a continuous, near-continuous,
real-time, quasi real-time, periodic, etc. process so the wearer is
effectively constantly being verified as known. In embodiments, the
HWC may be worn and eye security tracked for access to other
computer systems.
[0062] The eye imaging system may be used for control of the HWC.
For example, a blink, wink, or particular eye movement may be used
as a control mechanism for a software application operating on the
HWC or associated device.
[0063] The eye imaging system may be used in a process that
determines how or when the HWC 102 delivers digitally displayed
content to the wearer. For example, the eye imaging system may
determine that the user is looking in a direction and then HWC may
change the resolution in an area of the display or provide some
content that is associated with something in the environment that
the user may be looking at. Alternatively, the eye imaging system
may identify different user's and change the displayed content or
enabled features provided to the user. User's may be identified
from a database of users eye characteristics either located on the
HWC 102 or remotely located on the network 110 or on a server 112.
In addition, the HWC may identify a primary user or a group of
primary users from eye characteristics wherein the primary user(s)
are provided with an enhanced set of features and all other user's
are provided with a different set of features. Thus in this use
case, the HWC 102 uses identified eye characteristics to either
enable features or not and eye characteristics need only be
analyzed in comparison to a relatively small database of individual
eye characteristics.
[0064] FIG. 10 illustrates a light source that may be used in
association with the upper optics module 202 (e.g. polarized light
source if the light from the solid state light source is
polarized), and light source 404. In embodiments, to provide a
uniform surface of light 1008 to be directed towards the DLP of the
upper optical module, either directly or indirectly, the solid
state light source 1002 may be projected into a backlighting
optical system 1004. The solid state light source 1002 may be one
or more LEDs, laser diodes, OLEDs. In embodiments, the backlighting
optical system 1004 includes an extended section with a
length/distance ratio of greater than 3, wherein the light
undergoes multiple reflections from the sidewalls to mix of
homogenize the light as supplied by the solid state light source
1002. The backlighting optical system 1004 also includes structures
on the surface opposite (on the left side as shown in FIG. 10) to
where the uniform light 1008 exits the backlight 1004 to change the
direction of the light toward the DLP 302 and the reflective
polarizer 310 or the DLP 402 and the TIR wedge 418. The
backlighting optical system 1004 may also include structures to
collimate the uniform light 1008 to provide light to the DLP with a
smaller angular distribution or narrower cone angle. Diffusers
including elliptical diffusers can be used on the entrance or exit
surfaces of the backlighting optical system to improve the
uniformity of the uniform light 1008 in directions orthogonal to
the optical axis of the uniform light 1008.
[0065] FIGS. 10a and 10b show illustrations of structures in
backlight optical systems 1004 that can be used to change the
direction of the light provided to the entrance face 1045 by the
light source and then collimates the light in a direction lateral
to the optical axis of the exiting uniform light 1008. Structure
1060 includes an angled sawtooth pattern wherein the left edge of
each sawtooth clips the steep angle rays of light thereby limiting
the angle of the light being redirected. The steep surface at the
right (as shown)of each sawtooth then redirects the light so that
it reflects off the left angled surface of each sawtooth and is
directed toward the exit surface 1040. Structure 1050 includes a
curved face on the left side (as shown) to focus the rays after
they pass through the exit surface 1040, thereby providing a
mechanism for collimating the uniform light 1008.
[0066] FIG. 11a illustrates a light source 1100 that may be used in
association with the upper optics module 202. In embodiments, the
light source 1100 may provide light to a backlighting optical
system 1004 as described above in connection with FIG. 10. In
embodiments, the light source 1100 includes a tristimulus notch
filter 1102. The tristimulus notch filter 1102 has narrow band pass
filters for three wavelengths, as indicated in FIG. 11c in a
transmission graph 1108. The graph shown in FIG. 11b, as 1104
illustrates an output of three different colored LEDs. One can see
that the bandwidths of emission are narrow, but they have long
tails. The tristimulus notch filter 1102 can be used in connection
with such LEDs to provide a light source 1100 that emits narrow
filtered wavelengths of light as shown in figure 11d as the
transmission graph 1110. Wherein the clipping effects of the
tristimulus notch filter 1102 can be seen to have cut the tails
from the LED emission graph 1104 to provide narrower wavelength
bands of light to the upper optical module 202. The light source
1100 can be used in connection with a combiner 602 with a
holographic mirror or tristimulus notch mirror to provide narrow
bands of light that are reflected toward the wearer's eye with less
waste light that does not get reflected by the combiner, thereby
improving efficiency and reducing escaping light that can cause
faceglow.
[0067] FIG. 12a illustrates another light source 1200 that may be
used in association with the upper optics module 202. In
embodiments, the light source 1200 may provide light to a
backlighting optical system 1004 as described above in connection
with FIG. 10. In embodiments, the light source 1200 includes a
quantum dot cover glass 1202. Where the quantum dots absorb light
of a shorter wavelength and emit light of a longer wavelength (FIG.
12b shows an example wherein a UV spectrum 1202 applied to a
quantum dot results in the quantum dot emitting a narrow band shown
as a PL spectrum 1204) that is dependent on the material makeup and
size of the quantum dot. As a result, quantum dots in the quantum
dot cover glass 1202 can be tailored to provide one or more bands
of narrow bandwidth light (e.g. red, green and blue emissions
dependent on the different quantum dots included as illustrated in
the graph shown in FIG. 12c where three different quantum dots are
used. In embodiments, the LED driver light emits UV light, deep
blue or blue light. For sequential illumination of different
colors, multiple light sources 1200 would be used where each light
source 1200 would include a quantum dot cover glass 1202 with a
quantum dot selected to emit at one of the desired colors. The
light source 1100 can be used in connection with a combiner 602
with a holographic mirror or tristimulus notch mirror to provide
narrow transmission bands of light that are reflected toward the
wearer's eye with less waste light that does not get reflected.
[0068] Although embodiments of HWC have been described in language
specific to features, systems, computer processes and/or methods,
the appended claims are not necessarily limited to the specific
features, systems, computer processes and/or methods described.
Rather, the specific features, systems, computer processes and/or
and methods are disclosed as non-limited example implementations of
HWC. All documents referenced herein are hereby incorporated by
reference.
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