U.S. patent application number 17/678979 was filed with the patent office on 2022-06-09 for bird friendly electrochromic devices.
The applicant listed for this patent is View, Inc.. Invention is credited to Abhishek Anant Dixit, John Gordon Halbert Mathew, Luis Vidal Ponce Cabrera, Anshu A. Pradhan, Eithan Ritz, Robert T. Rozbicki.
Application Number | 20220179273 17/678979 |
Document ID | / |
Family ID | 1000006156802 |
Filed Date | 2022-06-09 |
United States Patent
Application |
20220179273 |
Kind Code |
A1 |
Mathew; John Gordon Halbert ;
et al. |
June 9, 2022 |
BIRD FRIENDLY ELECTROCHROMIC DEVICES
Abstract
Various embodiments herein relate to electrochromic windows that
are bird friendly, as well as methods and apparatus for forming
such windows. Bird friendly windows include one or more elements
that make the window visible to birds so that the birds recognize
that they cannot fly through the window. An electrochromic window
includes one or more transparent substrates, wherein at least one
of the substrates is an electrochromic (EC) lite including an
electrochromic device and a pattern formed on at least one of the
substrates by a laser, the pattern including a first feature
configured to provide a set of optical properties different than
optical properties of the transparent substrate. The set of optical
properties includes one or more characteristics of refractivity,
reflectivity and diffraction.
Inventors: |
Mathew; John Gordon Halbert;
(Novato, CA) ; Rozbicki; Robert T.; (Saratoga,
CA) ; Ponce Cabrera; Luis Vidal; (Olive Branch,
MS) ; Pradhan; Anshu A.; (Collierville, TN) ;
Dixit; Abhishek Anant; (Collierville, TN) ; Ritz;
Eithan; (Memphis, TN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
View, Inc. |
Milpitas |
CA |
US |
|
|
Family ID: |
1000006156802 |
Appl. No.: |
17/678979 |
Filed: |
February 23, 2022 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16427283 |
May 30, 2019 |
11307475 |
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17678979 |
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15738110 |
Dec 19, 2017 |
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16427283 |
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62191182 |
Jul 10, 2015 |
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62238609 |
Oct 7, 2015 |
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62269721 |
Dec 18, 2015 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02F 1/1533 20130101;
A01M 29/08 20130101 |
International
Class: |
G02F 1/153 20060101
G02F001/153; A01M 29/08 20060101 A01M029/08 |
Claims
1. An electrochromic window comprising: one or more transparent
substrates, wherein at least one of the substrates is an
electrochromic (EC) lite including an electrochromic device; and a
pattern formed on or in at least one of the substrates by a laser,
the pattern including a first feature configured to provide a set
of optical properties different than optical properties of the
transparent substrate; wherein the set of optical properties
includes one or more characteristics of refractivity, reflectivity
and diffraction.
2. The electrochromic window of claim 1, wherein the pattern is
formed on the EC lite.
3. The electrochromic window of claim 2, wherein the pattern is
formed on a surface of the EC lite opposite to the electrochromic
device.
4. The electrochromic window of claim 2, wherein the pattern is
formed on the EC light by operating the laser in a regime selected
to form the pattern without damaging the electrochromic device.
5. The electrochromic window of claim 4, wherein the pattern
includes a sequence of microcracks formed on a surface or in an
interior of the EC light by operating the laser.
6. The electrochromic window of claim 4, wherein the laser
operating regime includes a train of micro-pulses, each micro-pulse
being less than 10 nanoseconds duration.
7. The electrochromic window of claim 6, the train of micro-pulses
integrates into a laser exposure period of about 100-1000
microsecond.
8. The electrochromic window of claim 1, wherein the pattern is
formed on the EC light by operating the laser in a regime selected
to form the pattern elements by inducing local changes to a
refraction index of the EC light.
9. The electrochromic window of claim 8, wherein the laser-induced
local change to the refraction index is configured to result in the
pattern being visible to birds and invisible to humans.
10. The electrochromic window of claim 8, wherein the laser
operating regime results in a pulse fluence that creates local
densification of the EC light that locally increases the refractive
index of the EC light and is below a microcracking threshold of the
EC light.
11. The electrochromic window of claim 10, wherein the laser
operating regime includes a train of micro-pulses, each micro-pulse
being less than 20 nanoseconds duration.
12. The electrochromic window of claim 11, the train of
micro-pulses includes less than 100 micropulses.
13. The electrochromic window of claim 11, the train of
micro-pulses includes less than 20 micropulses.
14. The electrochromic window of claim 1, wherein the pattern
includes a diffraction grating on a surface of the EC light
opposite to the electrochromic device.
15. The electrochromic window of claim 14, wherein the diffraction
grating is formed on the EC light by operating the laser in a
regime selected to locally ablate micro-spots, each micro-spot
having a dimension in the range of 1 to 50 .mu.m.
16. The electrochromic window of claim 15, wherein the micro-spots
have a diameter to depth ratio greater than 20.
17. The electrochromic window of claim 1, wherein the
electrochromic window is configured such that the pattern is
positioned outboard of the electrochromic device.
18. The electrochromic window of claim 1, wherein the pattern is
formed on the window after the EC lite and at least one additional
transparent substrate are formed into an insulated glass unit
(IGU).
19. The electrochromic window of claim 1, wherein a first pattern
is formed on a first of the one or more substrates and a second
pattern is formed on a second of the one or more substrates.
20. The electrochromic window of claim 1, wherein the pattern
comprises elements including one or more intersecting or
non-intersecting stripes or bars and/or a plurality of dots.
21. The electrochromic window of claim 1, wherein at least some of
the elements have a cross sectional dimension of smaller than 0.5
mm.
22. The electrochromic window of claim 1, wherein at least some of
the elements have a cross sectional dimension of smaller than 0.2
mm.
23. An integrated glass unit (IGU) comprising: at least two
transparent substrates, wherein at least one of the substrates is
an electrochromic (EC) lite having an electrochromic device
disposed thereon; and a pattern formed on or in at least one of the
substrates by a laser, the pattern including a first feature
configured to provide a set of optical properties different than
optical properties of the transparent substrate; wherein the set of
optical properties includes one or more characteristics of
refractivity, reflectivity and diffraction.
24. The IGU of claim 23, wherein the pattern is formed on the EC
lite by operating the laser in a regime selected to form the
pattern without damaging electrochromic device.
25. The IGU of claim 23, wherein the pattern comprises elements
including one or more intersecting or non-intersecting stripes or
bars and/or a plurality of dots.
Description
INCORPORATION BY REFERENCE
[0001] An Application Data Sheet is filed concurrently with this
specification as part of the present application. Each application
that the present application claims benefit of or priority to as
identified in the concurrently filed Application Data Sheet is
incorporated by reference herein in its entirety and for all
purposes.
BACKGROUND
[0002] Electrochromism is a phenomenon in which a material exhibits
a reversible electrochemically-mediated change in an optical
property when placed in a different electronic state, typically by
being subjected to a voltage change. The optical property is
typically one or more of color, transmittance, absorbance, and
reflectance. One well known electrochromic material, for example,
is tungsten oxide (WO.sub.3). Tungsten oxide is a cathodic
electrochromic material in which a coloration transition,
transparent to blue, occurs by electrochemical reduction.
[0003] Electrochromic materials may be incorporated into, for
example, windows and mirrors. The color, transmittance, absorbance,
and/or reflectance of such windows and mirrors may be changed by
inducing a change in the electrochromic material. While
electrochromism was discovered in the 1960's, electrochromic
devices have not realized their full commercial potential.
[0004] Electrochromic windows show promise as a viable "green"
technology. As electrochromic glass is deployed in greater amounts,
there arises a need to produce products that address the need not
only for energy savings, aesthetics and occupant comfort, but also
other environmental issues.
SUMMARY
[0005] Various embodiments herein relate to electrochromic windows
that are patterned or otherwise fabricated to be bird friendly.
Also disclosed are methods and apparatus for fabricating such
windows. The pattern may be formed in a way that renders the window
visible to birds but not to humans, thereby reducing bird mortality
while ensuring an unobstructed view for human occupants. In certain
embodiments, electrochromic windows are augmented to include bird
friendly features that do not necessarily include a pattern.
[0006] In accordance with some embodiments, an electrochromic
window includes one or more transparent substrates, wherein at
least one of the substrates is an electrochromic (EC) lite
including an electrochromic device, and a pattern formed on or in
at least one of the substrates by a laser, the pattern including a
first feature configured to provide a set of optical properties
different than optical properties of the transparent substrate. The
set of optical properties includes one or more characteristics of
refractivity, reflectivity and diffraction.
[0007] In some examples, the pattern may be formed on the EC lite.
In some examples, the pattern may be formed on a surface of the EC
lite opposite to the electrochromic device. In some examples, the
pattern may be formed on the EC light by operating the laser in a
regime selected to form the pattern without damaging the
electrochromic device. In some examples, the pattern may include a
sequence of microcracks formed on a surface or in an interior of
the EC light by operating the laser. In some examples, the laser
operating regime may include a train of micro-pulses, each
micro-pulse being less than 10 nanoseconds duration. In some
examples, the train of micro-pulses may integrate into a laser
exposure period of about 100-1000 microsecond.
[0008] In some examples, the pattern may be formed on the EC light
by operating the laser in a regime selected to form the pattern
elements by inducing local changes to a refraction index of the EC
light. In some examples, the laser-induced local change to the
refraction index may be configured to result in the pattern being
visible to birds and invisible to humans. In some examples, the
laser operating regime may result in a pulse fluence that creates
local densification of the EC light that locally increases the
refractive index of the EC light and is below a microcracking
threshold of the EC light. In some examples, the laser operating
regime may include a train of micro-pulses, each micro-pulse being
less than 20 nanoseconds duration. In some examples, the train of
micro-pulses may include less than 100 micropulses. In some
examples, the train of micro-pulses may include less than 20
micropulses.
[0009] In some examples, the pattern may include a diffraction
grating on a surface of the EC light opposite to the electrochromic
device. In some examples, the diffraction grating may be formed on
the EC light by operating the laser in a regime selected to locally
ablate micro-spots, each micro-spot having a dimension in the range
of 1 to 50 .mu.m. In some examples, the micro-spots may have a
diameter to depth ratio greater than 20.
[0010] In some examples, the electrochromic window may be
configured such that the pattern is positioned outboard of the
electrochromic device.
[0011] In some examples, the pattern may be formed on the window
after the EC lite and at least one additional transparent substrate
are formed into an insulated glass unit (IGU).
[0012] In some examples, a first pattern may be formed on a first
of the one or more substrates and a second pattern is formed on a
second of the one or more substrates.
[0013] In some examples, the pattern may comprise elements
including one or more intersecting or non-intersecting stripes or
bars and/or a plurality of dots.
[0014] In some examples, at least some of the elements may have a
cross sectional dimension of smaller than 0.5 mm.
[0015] In some examples, at least some of the elements may have a
cross sectional dimension of smaller than 0.2 mm.
[0016] According to some embodiments, an integrated glass unit
(IGU) includes at least two transparent substrates, wherein at
least one of the substrates is an electrochromic (EC) lite having
an electrochromic device disposed thereon, and a pattern formed on
or in at least one of the substrates by a laser, the pattern
including a first feature configured to provide a set of optical
properties different than optical properties of the transparent
substrate. The set of optical properties includes one or more
characteristics of refractivity, reflectivity and diffraction.
[0017] In some examples, the pattern may be formed on the EC lite
by operating the laser in a regime selected to form the pattern
without damaging electrochromic device.
[0018] In some examples, the pattern may comprise elements
including one or more intersecting or non-intersecting stripes or
bars and/or a plurality of dots.
[0019] According to some embodiments, a method of fabricating an
electrochromic window includes preparing an electrochromic (EC)
lite of the EC window by disposing an EC device on a first
transparent substrate and forming, with a laser, a pattern on or in
at least one of the EC light and a second transparent substrates of
the electrochromic window, the pattern including a first feature
configured to provide a set of optical properties different than
optical properties of the transparent substrates. The set of
optical properties includes one or more characteristics of
refractivity, reflectivity and diffraction.
[0020] In some examples, forming the pattern on the EC light may
include operating the laser in a regime selected to form the
pattern without damaging electrochromic device. According to some
embodiments, the laser operating regime may include a train of
micro-pulses, each micro-pulse being less than 10 nanoseconds
duration and the train of micro-pulses integrates into a laser
exposure period of about 100-1000 microsecond.
[0021] In some examples, forming the pattern on the EC may include
operating the laser in a regime selected to form the pattern
elements by inducing local changes to a refraction index of the EC
light.
[0022] In some examples, the pattern may include a diffraction
grating on a surface of the EC light opposite to the electrochromic
device and forming the diffraction grating on the EC light includes
operating the laser in a regime selected to locally ablate
micro-spots, each micro-spot having a dimension in the range of 1
to 50 nm.
[0023] In some examples, the pattern may comprise elements
including one or more intersecting or non-intersecting stripes or
bars and/or a plurality of dots.
[0024] These and other features and advantages of the disclosed
embodiments will be described in further detail below, with
reference to the associated drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] The following detailed description can be more fully
understood when considered in conjunction with the drawings in
which:
[0026] FIG. 1 illustrates a cross sectional view of an
electrochromic device according to certain embodiments.
[0027] FIG. 2A depicts the spectral sensitivity for an ultraviolet
sensitive (UVS) bird over a range of wavelengths.
[0028] FIG. 2B depicts the spectral sensitivity for humans over a
range of wavelengths.
[0029] FIG. 3A illustrates a gap through which a small bird can
fly.
[0030] FIGS. 3B-3H show various patterns that may be used when
designing a patterned bird friendly window according to certain
embodiments.
[0031] FIGS. 4A-4L present various embodiments of a bird friendly
electrochromic window having a patterned layer and an
electrochromic stack positioned at various locations.
[0032] FIGS. 4M, 4N, 4P, 4Q, and 4R depict embodiments of triple
paned bird friendly electrochromic windows having a patterned layer
and an electrochromic stack positioned at various locations.
[0033] FIGS. 4S-4X depict embodiments of triple paned bird friendly
electrochromic windows having a bird friendly layer, an
electrochromic stack and a low-E coating each positioned at various
locations.
[0034] FIG. 4Y depicts a double pane IGU where the outboard lite is
a laminate of an electrochromic lite and a non-electrochromic lite
with bird friendly patterning thereon.
[0035] FIG. 4Z is a graph showing the reflectance vs. wavelength
where different thicknesses of titanium oxide are provided on an
electrochromic insulated glass unit.
[0036] FIGS. 5A-5G depict cross-sectional views of various
embodiments of electrochromic devices that are patterned to be bird
friendly.
[0037] FIGS. 6A and 6B are flow charts describing methods of
fabricating the devices shown in FIGS. 5A-5G.
[0038] FIG. 7A is a graph showing the reflectance vs. wavelength
where an electrochromic insulated glass unit includes either a
layer of titanium oxide or a layer of silicon oxide.
[0039] FIG. 7B is a graph showing transmission vs. wavelength for
different types of glass.
[0040] FIGS. 8A-8C show views of integrated deposition systems that
may be used to form electrochromic devices as described herein.
[0041] FIG. 9A illustrates an example of forming a pattern on a
surface of a glass substrate, according to an embodiment.
[0042] FIG. 9B illustrates an example of forming a pattern in the
interior of a glass substrate, according to an embodiment.
[0043] FIGS. 10A-C illustrate an example of forming a diffraction
grating, according to an embodiment.
[0044] FIG. 11 is a flow chart illustrating an example method of
forming a pattern on a transparent substrate of an electrochromic
window, according to an implementation.
DETAILED DESCRIPTION
[0045] A schematic cross-section of an electrochromic device 100 in
accordance with some embodiments is shown in FIG. 1. The
electrochromic device includes a substrate 102, a conductive layer
(CL) 104, a defect-mitigating insulating layer (DMIL) 105, an
electrochromic layer (EC) 106 (sometimes also referred to as a
cathodically coloring layer or a cathodically tinting layer), an
ion conducting layer or region (IC) 108, a counter electrode layer
(CE) 110 (sometimes also referred to as an anodically coloring
layer or anodically tinting layer), and a conductive layer (CL)
114. Elements 104, 105, 106, 108, 110, and 114 are collectively
referred to as an electrochromic stack 120. A voltage source 116
operable to apply an electric potential across the electrochromic
stack 120 effects the transition of the electrochromic device from,
e.g., a clear state to a tinted state. In other embodiments, the
order of layers is reversed with respect to the substrate. That is,
the layers are in the following order: substrate, conductive layer,
defect-mitigating-insulating layer, counter electrode layer, ion
conducting layer, electrochromic material layer, conductive
layer.
[0046] In various embodiments, the ion conductor region 108 may
form from a portion of the EC layer 106 and/or from a portion of
the CE layer 110. In such embodiments, the stack 120 may be
deposited to include cathodically coloring electrochromic material
(the EC layer) in direct physical contact with an anodically
coloring counter electrode material (the CE layer). The ion
conductor region 108 (sometimes referred to as an interfacial
region, or as an ion conducting substantially electronically
insulating layer or region) may then form where the EC layer 106
and the CE layer 110 meet, for example through heating and/or other
processing steps. In some embodiments, the device contains no ion
conductor region as deposited.
[0047] In various embodiments, one or more of the layers shown in
FIG. 1 may be deposited to include two or more sublayers. In one
example, the EC layer 106 and/or the CE layer 110 may be deposited
to include two or more sublayers. The sublayers within a given
layer may have different compositions and/or morphologies. The
sublayers may be included to promote formation of the ion
conducting region 108 and/or to tune various properties of the
electrochromic device 100.
[0048] Further, an electrochromic device may include one or more
additional layers not shown in FIG. 1. Such layers may improve
optical performance, durability, hermeticity, and the like.
Examples of additional layers that may be used include, but are not
limited to, anti-reflective layers, additional defect-mitigating
insulating layers (which may be provided within or between any of
the layers shown in FIG. 1), and/or capping layers. The techniques
disclosed herein are applicable to a wide variety of electrochromic
device designs.
[0049] In normal operation, the electrochromic device reversibly
cycles between at least two optical states such as a clear state
and a tinted state. In the clear state, a potential is applied to
the electrochromic stack 120 such that available ions in the stack
that can cause the electrochromic material 106 to be in the tinted
state reside primarily in the counter electrode 110. When the
potential on the electrochromic stack is reversed, the ions are
transported across the ion conducting layer 108 to the
electrochromic material 106 and cause the material to enter the
tinted state.
[0050] It should be understood that the reference to a transition
between a clear state and tinted state is non-limiting and suggests
only one example, among many, of an electrochromic transition that
may be implemented. Unless otherwise specified herein, whenever
reference is made to a clear-tinted transition, the corresponding
device or process encompasses other optical state transitions such
as non-reflective-reflective, transparent-opaque, etc. Further the
terms "clear" and "bleached" refer to an optically neutral state,
e.g., untinted, transparent or translucent. Still further, unless
specified otherwise herein, the "color" or "tint" of an
electrochromic transition is not limited to any particular
wavelength or range of wavelengths. As understood by those of skill
in the art, the choice of appropriate electrochromic and counter
electrode materials governs the relevant optical transition.
[0051] In certain embodiments, all of the materials making up
electrochromic stack 120 are inorganic, solid (i.e., in the solid
state), or both inorganic and solid. Because organic materials tend
to degrade over time, inorganic materials offer the advantage of a
reliable electrochromic stack that can function for extended
periods of time. Materials in the solid state also offer the
advantage of not having containment and leakage issues, as
materials in the liquid state often do. Each of the layers in the
electrochromic device is discussed in detail, below. It should be
understood that any one or more of the layers in the stack may
contain some amount of organic material, but in many
implementations one or more of the layers contains little or no
organic matter. The same can be said for liquids that may be
present in one or more layers in small amounts. It should also be
understood that solid state material may be deposited or otherwise
formed by processes employing liquid components such as certain
processes employing sol-gels or chemical vapor deposition.
[0052] While windows (and electrochromic windows in particular) can
be used to create an aesthetically pleasing building design, they
can also present problems to certain animals. In particular, birds
may fail to appreciate the presence of a window and try to fly
through it. The reflective or transparent nature of windows makes
them difficult to detect by birds. This problem may be particularly
bad when the windows are positioned near areas with trees, shrubs,
and other plant life to which the bird may be attracted. In some
cases a bird may be attracted to an item behind the window, and in
other cases a bird may be attracted to an image reflected in the
glass. Unfortunately, many birds do not survive a collision with a
window, and some of those who survive may be injured by the
collision. Given the energy savings potential and occupant comfort
aspects of electrochromic windows, it is expected that large
numbers of electrochromic windows will be deployed in the coming
years; thus, bird friendly options are necessary.
Avian Vision vs. Human Vision
[0053] Various embodiments herein relate to electrochromic or other
windows having one or more optical characteristics that dissuade
birds from flying into the windows. Such windows may be referred to
as bird friendly windows. Certain embodiments may also relate to
particular portions (e.g., layers or stacks of layers) of a bird
friendly window, as well as methods and apparatus for making such
windows. The techniques described herein are also applicable to
electrochromic devices incorporated into other (non-window)
products as appropriate, and to other optically switchable devices
such as liquid crystal devices and electrophoretic devices, which
may be incorporated into window products or other products.
[0054] In order for a window to be considered bird friendly, it
should include one or more features that make the window appear to
the bird as if the window cannot be flown through. One technique
involves patterning the window so that a bird will see contrasting
features and believe it cannot fit through the spaces in the
pattern. Unfortunately, conventional patterning can also
deleteriously affect the view through the window for human
occupants. Because windows are typically used (at least in part) to
provide human occupants with a view to the outside, such patterning
is undesirable if it can be perceived by human eyes. As such,
various techniques described herein may be used to render an
electrochromic window pattern visible to birds (such that birds are
discouraged from trying to fly through the window) while
maintaining an unobstructed view through the window for humans,
that is, they are selective so that birds see the visual deterrent
while to humans the deterrent is e.g., visually indiscernible or
nearly so. In certain embodiments, an electrochromic window may be
patterned such that birds can see the pattern and humans cannot.
For instance, the pattern may reflect, absorb, or scatter light
only in wavelengths that are visible to birds but not humans (e.g.,
only reflecting in ultraviolet wavelengths, as explained further
with regard to FIGS. 2A and 2B, below). In these or other cases, an
electrochromic window may be fabricated to appear hazy to birds but
clear to humans (e.g., the window may scatter substantial amounts
of light at UV wavelengths but not at wavelengths visible to
humans).
[0055] Both human and avian eyes use two types of light receptors:
rods and cones. Rods are sensitive to small quantities of light and
are better for vision during the night. Cones detect specific
wavelengths of light and are better suited for seeing color. Humans
are trichromatic and have only three types of cones in their eyes,
each having a distinctive response range of wavelengths with a
maximum absorbance peak. By contrast, most birds are
tetrachromatic, having four different types of cones. Some studies
have also suggested that certain birds may be pentachromatic,
having five different types of cones.
[0056] Color vision in birds can be categorized into two groups:
violet sensitive (VS) and ultraviolet sensitive (UVS). Birds having
UVS vision have a pigment in their cones that absorbs UV light,
thereby allowing these birds to see into the UV spectrum. It is
believed that the majority of avian species have UVS vision,
including birds that are in the clades of palaeognathae (ratites
and tinamous), charadriiformes (shorebirds, gulls, and alcids),
trogoniformes (trogons), psittaciformes (parrots), and
passeriformes (perching birds). (Odeen A, Hastad O: The
phylogenetic distribution of ultraviolet sensitivity in birds. BMC
Evol Biol 2013, 13:36). In nature, birds may take advantage of this
UV vision through courtship (e.g., using UV reflective plumage to
attract mates), hunting (e.g., tracking UV reflection of rodent
waste), and other adaptations. In many embodiments, electrochromic
windows are designed to be "bird friendly" to birds that have UVS
vision.
[0057] FIG. 2A presents a graph showing the spectral sensitivity
for a typical UVS bird, a Eurasian blue tit (cyanistes caeruleus),
with each peak relating to one of the four types of cones in a bird
eye. This graph is adapted from FIG. 1 of the Odeen/Hastad paper
mentioned above. FIG. 2B presents a graph showing the spectral
sensitivity for a typical human, with each peak relating to one of
the three types of cones in a human eye. Together, FIGS. 2A and 2B
illustrate that birds are capable of seeing wavelengths that are
below wavelengths viewable by humans. The range between about
300-400 nm is particularly relevant, with bird vision being much
better than human vision in this range. The bird cone capable of
seeing into UV has a peak around 370 nm. As such, patterns or other
modifications that make the window visible/noticeable at a
wavelength range between about 320-390 nm, or between about 350-385
nm, or between about 360-380 nm may be particularly useful. In some
embodiments, the pattern or other modification makes the window
visible/noticeable at wavelengths under about 400 nm, or at
wavelengths under about 390 nm, or at wavelengths under about 380
nm. The wavelengths over which the pattern or other window
modification is noticeable may be within the range of wavelengths
that corresponds to UVA (between about 315-400 nm) and/or UVB
(between about 280-315 nm). Wavelengths in UVA may be most useful,
based on the data summarized in FIG. 2A.
Pattern Design Considerations
[0058] In certain embodiments, a window may include a pattern that
is visible to birds. The pattern may be positioned in a number of
places. In some cases, the pattern is disposed on an electrochromic
pane. An electrochromic pane includes a transparent substrate with
an electrochromic device coating thereon. Typically, the
electrochromic device is provided on one surface of the pane, but
in some cases an electrochromic device is provided on both primary
surfaces (the interior facing surface and the exterior facing
surface) of a particular pane. In some embodiments, the
electrochromic pane is provided in an assembly having two or more
panes such as an insulated glass unit or a laminate of two or more
panes. That is, a non-electrochromic pane may be paired with an
electrochromic pane in an IGU in some cases. A non-electrochromic
pane may also be laminated to an electrochromic pane in some cases.
An IGU may include such laminate(s) or no laminates. A bird-visible
pattern may reside on an electrochromic pane, a non-electrochromic
pane, or both.
[0059] Various embodiments herein relate to techniques where the
patterned layer is provided on the interior of an IGU or a laminate
(i.e., the patterned layer is positioned at some location between
two panes). A patterned layer may also be provided outside of two
panes in an IGU in certain embodiments (e.g., on an exterior-facing
outer pane (often referred to as surface 1) or on an
interior-facing inner pane (often referred to as surface 4), or on
an additional layer/substrate that may be attached (e.g.,
laminated) onto surfaces 1 or 4. In many embodiments, a patterned
layer may be provided on the same pane as an electrochromic device.
In other words, an electrochromic pane may be patterned to be bird
friendly. The patterning may be on the surface with the EC coating
or the surface without the EC coating, or both. In these or other
embodiments, a patterned layer may be provided on a
non-electrochromic pane. The patterned, non-electrochromic pane may
be associated with an electrochromic pane in an IGU, or laminated
to an electrochromic pane as mentioned above.
[0060] In various embodiments, an electrochromic device may be
fabricated to include a defect-mitigating-insulating layer (DMIL),
also referred to as a buffer layer. The buffer layer may be
provided, at least in part, to minimize the risk of fabricating
defective devices by preventing a short circuit within the
electrochromic device. The buffer layer may be patterned such that
birds can recognize the window as something they cannot fly
through, while still maintaining a clear view for human occupants.
One example buffer layer/DMIL is shown in FIG. 1 as element 105.
Buffer layers may also be provided at various other locations in an
electrochromic device, as described herein. Buffer layers/DMILs are
further discussed and described in U.S. Pat. No. 9,007,674, which
is herein incorporated by reference in its entirety. In various
embodiments, a buffer layer may have an electronic resistivity
between about 1 and 5.times.10.sup.10 Ohm-cm. One example of a
buffer layer material that can be patterned is titanium oxide,
though the embodiments are not so limited. Titanium oxide DMILs are
beneficial regardless of whether such layers are patterned for
bird-friendliness.
[0061] In various embodiments, the patterned layer may include a
material that has different optical properties at (a) a wavelength
(or range of wavelengths) visible by birds, compared to (b)
wavelengths visible by humans. For instance, the patterned layer
may include a material that has a high reflectance in UV and a low
reflectance in the range of wavelengths visible by humans. This
material may form one pattern element that contrasts with a second
pattern element that may be effectively invisible to both birds and
humans, thereby defining a pattern that is perceivable by birds but
not humans.
[0062] In some embodiments, the patterned layer may include an
oxide material (or nitride or carbide material in some
embodiments), for example a metal oxide. In some cases, the
patterned layer may include a material that exhibits different
optical properties (e.g., refractive
index/reflectance/transmissivity/scattering/etc.) depending on its
thickness. In a particular example, the patterned layer is titanium
oxide (TiO.sub.x), which has a higher index of refraction at UV
wavelengths than at wavelengths visible by humans. Advantageously,
the thickness of the TiO.sub.x affects how light interacts with the
TiO.sub.x, and a layer of TiO.sub.x can be patterned to different
thicknesses to achieve a pattern perceivable by birds but not by
humans. In such embodiments, one pattern element may be made of
relatively thinner TiO.sub.x, and a second pattern element (which
contrasts with the first pattern element) may be made of relatively
thicker TiO.sub.x. Other examples of materials that may behave
similarly include, but are not limited to, various oxides,
nitrides, and carbides, including but not limited to aluminum
oxide, tantalum oxide, tin oxide, silicon oxide, aluminum nitride,
and silicon nitride. In some cases a patterned layer will act as a
DMIL/buffer layer, or as a portion thereof. In some other cases, a
patterned layer may be shaped and/or located at a position that
would render it unsuitable as a DMIL (e.g., the layer may include
incomplete coverage of TiO.sub.x or other DMIL material, or it may
be positioned outside the pair of conductive layers, for instance
between a glass substrate and a conductive layer). Further, the
patterned layer may be made of a material that is not suitable as a
DMIL (e.g., the patterned layer may be of the same material as a
DMIL, or not, and may or may not be sufficiently insulating to act
as a DMIL).
[0063] In various implementations, a material used for a patterned
layer may have certain properties. For example, the material may be
substantially transparent in UV (e.g., between about 300-400 nm, in
some cases below about 350 nm). The material may have an index of
refraction that is different from that of the substrate. In many
cases, the material used for a patterned layer has a difference in
n and/or k values between the UV region (e.g., between about
300-400 nm) and the human visible region (e.g., between about
400-700 nm). These n and k values relate to the refractive index of
the material.
[0064] Techniques for creating a bird-visible pattern are discussed
further below. Briefly, the pattern produces contrasts between two
or more pattern features, particularly where such contrasts occur
at wavelengths in the UV spectrum. The pattern features include at
least two components that contrast with one another (selectively to
birds). For instance, with respect to a chess board, the pattern
features include both the black squares (which may be considered
first features) and the white squares (which may be considered
second features). With respect to an empty tic-tac-toe board, the
pattern features include the black lines (which may be considered
first features) and the white spaces (which may be considered
second features) between the lines. With respect to a patterned
window that includes at least two contrasting properties, the
pattern features include both the areas having a first property
(e.g., a first refractive index in UV) and the areas having a
second property (e.g., a second refractive index in UV).
[0065] In a number of cases, the pattern has certain
characteristics to discourage birds from trying to fly through the
window. For instance, the pattern may have particular dimensions so
that a bird will think they cannot fit through spaces in the
pattern. It has been observed that small birds will not fly through
surfaces that have two inches or less of untreated horizontal space
or four inches or less of untreated vertical space. In other words,
a bird will not try to fly through a vertically oriented "opening"
if the opening appears to be less than about four inches wide, nor
will it try to fly through a horizontally oriented "opening" if the
opening appears to be less than about two inches tall. The
"opening" perceived by the bird is a portion of the glass itself,
and is not actually an opening.
[0066] FIG. 3A illustrates the minimum height and minimum width of
an area through which a typical small bird will fly. If a bird
perceives that a gap is thinner than about 4 inches wide and/or
shorter than about 2 inches tall (or vice versa), it will generally
recognize the gap as too small to fit through, and will not try to
fly through the gap. As such, in various embodiments, a window may
be patterned such that the pattern features are shorter than about
2 inches tall (e.g., shorter than about 1.75 inches tall, or
shorter than about 1.5 inches tall) and/or thinner than about 4
inches wide (e.g., thinner than about 3.5 inches wide, or thinner
than about 3 inches wide). In some embodiments, the smallest linear
dimension of one or more pattern features (in some cases all
pattern features) may be about 4 inches or less, or about 2 inches
or less. Such dimensions may refer to all pattern elements, or only
to pattern elements which a bird might perceive to be an opening
through which it can fly. In one example, a pattern may be made of
two contrasting pattern elements including one pattern element that
a bird perceives as an opening and one pattern element that a bird
perceives as solid. The pattern element that appears to be an
opening may have the dimensions listed in this paragraph, while the
other pattern element which appears to be solid may or may not have
the dimensions listed in this paragraph.
[0067] Further, in some embodiments, the pattern features may be
greater than about 0.25 inches tall and wide to help ensure that
the birds can see the pattern. In various embodiments, the smallest
dimension of a pattern feature may be at least about 0.25 inches.
If the pattern features are smaller than 0.25 inches, the bird may
not see the pattern feature until it is too close to the window to
avoid collision (if the bird sees the pattern at all). However,
certain patterns may have pattern features that fall outside the
guidelines presented above. For instance, in some cases the pattern
features may be shorter than 2 inches tall, thinner than about 4
inches wide, and/or smaller than about 0.25 inches tall/wide.
[0068] FIGS. 3B-3H illustrate various patterned windows according
to certain embodiments. In FIG. 3B, the pattern includes horizontal
stripes 302 and gaps 303. The stripes 302 and gaps 303 are both
considered to be pattern features. For instance, the horizontal
stripes 302 may be considered a first pattern feature and the gaps
303 may be considered a second pattern feature. The stripes 302
contrast with the gaps 303. For instance, the stripes 302 may have
different reflectance values or scattering properties than the gaps
303, particularly and selectively in the UV range. As understood by
those of skill in the art, reflectance values can be controlled by
adjusting refractive index. Certain dimensions are labeled in FIG.
3B. In particular, dimension 304 is the height of the stripes 302,
and dimension 305 is the height of the gaps 303. In various
embodiments, either or both of dimensions 304 and 305 may be at
least about 0.25 inches tall, and shorter than about 2 inches.
Where dimensions 304 and/or 305 are greater than 2 inches, a small
bird may perceive that it can fly through either the stripe 302 or
the gap 303, depending on the optical properties of the stripe 302
and gap 303. Dimensions 304 and/or 305 may be uniform or
non-uniform throughout the window. In other words, various stripes
302 and/or gaps 303 may have different and/or varying heights in
some cases. Further, dimension 304 may be smaller, larger, or about
equal to dimension 305.
[0069] FIG. 3C illustrates a patterned window where the pattern
includes a series of vertical stripes 312 and gaps 313. The
vertical stripes 312 may be considered a first pattern feature and
the gaps 313 may be considered a second pattern feature. As noted
above with respect to FIG. 3B, the stripes 312 contrast with the
gaps 313, selectively in the UV range. For example, the stripes 312
may have different refractive indices or scattering properties
compared to the gaps 313. Certain dimensions are labeled in FIG. 3B
including dimension 314, which is the width of the stripes 312, and
dimension 315, which is the width of the gaps 313. In certain
embodiments, dimensions 314 and/or 315 are at least about 0.25
inches wide, and less than about 4 inches wide. Dimensions 314 and
315 may be uniform or non-uniform throughout the window. As such,
various stripes 312 and/or gaps 313 may have different and/or
varying widths. Dimension 314 may be smaller, larger, or about
equal to dimension 315.
[0070] FIG. 3D illustrates a patterned window where the pattern
includes a series of horizontal stripes 321, vertical stripes 322,
and gaps 323. The horizontal and vertical stripes 321 and 322,
respectively, may be considered a first pattern feature and the
gaps 323 may be considered a second pattern feature. The dimensions
of the stripes 321 and 322 and gaps 323 may be as described above.
The stripes 321 and 322 contrast with the gaps 323. For instance,
the stripes 321 and 322 may have a reflectance value and/or
scattering properties than the gaps 323, particularly and
selectively in the UV range.
[0071] FIG. 3E illustrates a patterned window where the pattern
includes alternating blocks 332 and 333 that have contrasting
properties. Blocks 332 may be considered a first pattern feature
and blocks 333 may be considered a second pattern feature. In
various cases the blocks 332 and 333 may have different reflectance
values (as set by, e.g., refractive indices), scattering
coefficients, etc. selectively in the ultraviolet region where bird
visual perception is significantly stronger than human visual
perception. The dimensions of the blocks 332 and 333 may fall
within the dimensions listed above.
[0072] FIG. 3F illustrates a patterned window where the pattern
includes a series of dots 342 and space 343 between the dots. The
dots 342 may be considered a first pattern feature and the space
343 may be considered a second pattern feature. The dots 342
contrast with the space 343. For example, the dots 342 may have a
reflectance value and/or scattering properties than the space 343.
Such contrast may be selectively in the UV range of wavelengths.
Certain dimensions are shown in FIG. 3F including dimension 344,
which is the diameter of the dots 342, dimension 345, which is the
height of the vertical space between dots 342 that are in the same
column, and dimension 346, which is the width of the horizontal
space between dots 342 that are in the same row. The dots may in
some cases have a diameter, dimension 344, that is at least about
0.25 inches. Dimension 345 may fall within the vertical dimensions
listed above, for example less than about 2 inches. Dimension 346
may fall within the horizontal dimensions listed above, for example
less than about 4 inches. In some embodiments, the dots may be of
varying sizes. Further, the dots may be oriented in a less regular
pattern. In further embodiments, the dots may not be circular dots,
but rather any shapes, regular or irregular, and mixtures of shapes
are contemplated.
[0073] FIG. 3G illustrates a patterned window where the pattern
includes a series of short vertically oriented bars 352 and space
353 between the bars. The bars 352 may be considered a first
pattern feature and the space 353 may be considered a second
pattern feature. The bars 352 contrast with the space 353. In
various embodiments, the bars 352 may have a different reflectance
value and/or scattering properties than the space 353. The bars 352
may have a minimum width and length of about 0.25 inches in various
embodiments. The bars 352 may have a particular length to width
aspect ratio, for example at least about 2:1, at least about 3:1,
at least about 5:1, at least about 10:1, or at least about 20:1.
Further, the space 353 between the bars 352 may in any given area
have a local vertical dimension of less than about 2 inches and/or
a local horizontal dimension of less than about 4 inches. The
pattern in FIG. 3G is similar to the pattern in FIG. 3C, except
that the stripes are provided as discontinuous bars. In FIG. 3G,
the bars in different columns are offset from one another such that
bars in one column overlap vertically with bars in an adjacent
column (though such bars remain horizontally separated in different
columns, as shown). In another embodiment, the bars are aligned
with one another such that the bars in one column do not overlap
with bars in an adjacent column. In another embodiment, the bars
may be oriented horizontally. Such an embodiment would be similar
to that shown in FIG. 3B, except that the stripes would be
discontinuous. In these embodiments, the bars may be offset from
one another such that bars in adjacent rows overlap with one
another horizontally (though such bars would remain vertically
separated in different rows), or the bars may be aligned such that
bars in one row do not overlap bars in an adjacent row.
[0074] FIG. 3H presents a patterned window where the pattern
includes a series of randomly oriented stripes 362 with space 363
between the stripes 362. The stripes 362 may be considered a first
pattern feature and the spaces 363 may be considered a second
pattern feature. A random orientation of stripes or other shapes
can be useful, particularly where the spaces 363 (and/or stripes
362) are each individually about 2 inches or less vertically and/or
about 4 inches or less horizontally.
[0075] The patterns shown in FIGS. 3B-3H are merely examples. Those
of ordinary skill in the art would appreciate that many patterns
are available and within the scope of the disclosed
embodiments.
[0076] In certain embodiments, the patterned layer is integrated
with a series of layers in a stack that provides areas of
constructive and/or destructive interference over the face of the
glass, particularly over the UV range. Such interference may define
the pattern seen by a bird. Factors that may contribute to
formation of such interference include the material(s) used to
fabricate the pattern, the refractive index of such materials, as
well as the thickness of such materials. The
constructive/destructive interference may be strong in the UV
spectrum visible by birds and weak in the spectrum visible by
humans. In some embodiments, the stack of materials is engineered
to produce controlled regions of interference. Material properties
relevant to producing this interference include the n vs. .lamda.
behavior, and/or the k vs. .lamda. behavior of the material.
[0077] In various embodiments, a pattern may be discernable but not
particularly noticeable by humans. In other words, humans may be
able to see the pattern if they are looking closely and/or
carefully, but would not otherwise be likely to notice the
pattern.
Methods of Patterning an Electrochromic Window
[0078] While non-electrochromic windows can be modified to be bird
friendly, electrochromic windows present an opportunity to use
electrochromic device components to assist in presenting patterns
selectively visible to birds. In particular, because electrochromic
windows are fabricated to include a number of different layers
(many of which are transparent thin films, and many of which are
all solid-state and inorganic), one or more of these layers can be
patterned to make the window visible to birds. Some of the layers
that can be so patterned are not present in typical
non-electrochromic windows.
[0079] As noted above, a pattern includes at least two contrasting
components selectively visible to birds. Such components may be
referred to as features or pattern features. A first component of
the pattern may be effectively invisible to both birds and humans,
while a second component of the pattern may be visible only to
birds and invisible to humans. This results in a pattern that is
perceivable by birds but invisible to humans. Put another way, the
pattern may be formed to include a first component that (a)
contrasts with a second component, such that the pattern formed
from the first and second components is perceivable, and (b)
exhibits different optical properties at UV vs. human visible
wavelengths, such that the pattern formed from the first and second
components is perceivable at UV wavelengths visible to birds, but
not at wavelengths visible by humans.
[0080] In various embodiments, the refractive index may be
different between the two contrasting components at a wavelength
that is visible by birds but not humans. When used without
qualification herein, the refractive index is intended to refer to
the complex refractive index. The complex refractive index (n) can
be defined in terms of its real part (n), which indicates the phase
velocity, and its imaginary part (.kappa.), which indicates the
extinction coefficient or mass attenuation coefficient. In
particular, n=n+i.kappa..
[0081] In some embodiments, the contrasting components of the
pattern are made of materials that have n values that differ by at
least about 0.3 at a UV wavelength visible by birds (but not
humans). In these or other embodiments, the contrasting components
of the pattern may have K values that differ by at least about 0.01
at a UV wavelength visible by birds (but not humans). In these or
other embodiments, the contrasting components of the pattern may
have n values that differ by about 0.1 or less at wavelengths in
the range between about 400-700 nm, and/or K values that differ by
about 0.005 or less at wavelengths in the range between about
400-700 nm. In one example, a pattern is made of a first component
and a second component. The first and second components may be
stripes and gaps, respectively, as shown in FIG. 3B for example.
The first component (e.g., stripes 302 in FIG. 3B) may be visible
to birds and invisible to humans, while the second component (e.g.,
gaps 303 in FIG. 3B) may be invisible to both birds and humans.
Because the first component/stripes 302 exhibit different optical
properties at UV wavelengths compared to wavelengths visible by
humans, and because the first component/stripes 302 contrast with
the second component/gaps 303 at UV wavelengths, the pattern is
perceivable by birds but not humans.
[0082] The reflectance (R) of a material is controlled by the
refractive index of the material. Specifically,
R=((n-1)/(n+1)).sup.2. In some embodiments, the contrasting
components of the pattern have reflectances that differ by at least
about 5%, in some cases at least about 15% at wavelengths between
about 300-400 nm, or between about 350-400 nm, for example at about
370 nm. Such reflectance differences may not be visible by humans,
for example where the reflectance differences are below a human
perceivable threshold in the range between about 400-700 nm.
[0083] In various embodiments, the contrasting components of the
pattern may have different reflection properties, scattering
properties, absorption properties, transmission properties,
etc.
Layers for Patterning
[0084] A number of different layers in or on an electrochromic
window can be patterned to provide contrasting components that make
the window visible to birds. As noted above, a patterned layer may
be provided on an electrochromic pane and/or on a
non-electrochromic pane. If a patterned layer is provided on a
non-electrochromic pane, it may be provided together with an
electrochromic pane, for example in an IGU and/or in a laminate
structure. Similarly, a patterned electrochromic pane may be
provided in an IGU and/or in a laminate structure as desired. The
patterned layer may be provided on any surface of an IGU, and in
some cases is provided between the panes of the IGU. In one example
where the patterned layer is provided on the interior of an IGU,
the patterned layer also acts as a defect-mitigating insulating
layer, as described above.
[0085] In some embodiments, the patterned layer is provided next to
a substrate layer. In one example, the pattern is formed directly
on the substrate. The patterned layer may be positioned such that
it is closer to the outside environment than the substrate, or vice
versa. A protective cover may be provided (e.g., laminated or
otherwise formed) on the patterned layer to protect it from
damage.
[0086] The patterned layer should be positioned such that the
pattern is perceivable by birds. Placing the pattern closer to the
bird and farther away from the interior of the building may help
make the pattern more perceivable by the birds.
[0087] For reference, in an IGU having two panes, the
exterior-facing surface of the exterior pane is typically referred
to as S1, the interior-facing surface of the exterior pane is
referred to as S2, the exterior-facing surface of the interior pane
is referred to as S3, and the interior-facing surface of the
interior pane is referred to as S4. In other words, going from the
external environment inwards, the surfaces are referred to as S1,
S2, S3, and S4, with S4 being the surface that a building occupant
can physically touch, and S1 being the surface exposed to the
outside environment. Surfaces that are relatively closer to the
external environment are referred to as "outboard" surfaces, while
surfaces that are relatively closer to the interior of the building
are referred to as "inboard" surfaces. For example, S1 is outboard
of S2, S3, and S4.
[0088] When an IGU is provided with a single electrochromic pane,
the electrochromic pane can be the interior pane (having surfaces
S3 and S4) or the exterior pane (having surfaces S1 and S2). The
electrochromic device can be positioned on any of surfaces S1-S4.
One benefit of including an electrochromic device on S1 and/or S2
is that the solar heat gain through the window can be minimized. An
electrochromic device can absorb solar energy and become fairly
warm. When the electrochromic device is provided on S1 and/or S2,
the warm electrochromic device is on the outboard lite, and any
argon (or other gas) provided interior of the IGU can act as a
thermal barrier to minimize the amount of heat that enters the
building as a result of the warm electrochromic device.
[0089] In some other embodiments, the electrochromic device may be
provided on S3 and/or S4. In these implementations, the solar heat
gain through the window may be relatively higher due to the fact
that the interior pane of the IGU will become warm, thereby heating
the building interior to a greater extent. Without the ICU's
internal gas pocket to act as a thermal barrier between the
electrochromic device and the interior of the building, the heat
gain through the windows may be relatively higher. However, this
may be mitigated by using a triple-pane IGU, having surfaces S1-S6
(in this example, S6 is the surface which a building occupant can
physically touch), where the EC device is on S3 or S4, and yet,
there is still an inert gas barrier between the warm EC device and
the interior of the building due to the presence of the third pane
with surfaces S5 and S6. Thus one embodiment is a triple pane IGU
having one or more bird friendly features on S1 and/or S2, and one
or more EC device on S3 and/or S4. Triple pane IGU embodiments are
further discussed below in the context of FIGS. 4M-4X.
[0090] Another way to combat the heat gain through the window is to
use a low-emissivity coating outboard of the electrochromic device.
This strategy is particularly effective where the low-emissivity
coating reduces the amount of infrared energy that passes through
the window onto an EC coating, for example an EC coating on S3
and/or S4 (or otherwise inboard of the low-emissivity coating). The
low-emissivity coating may block (e.g., reflect) a relatively
higher degree of IR energy and a relatively lower degree of UV
energy in some cases, thereby permitting the electrochromic device
to be located on S3 or S4, and ensuring that the patterned layer
remains visible to the birds outside (regardless of where the
patterned layer is located). In various embodiments, a
low-emissivity coating may be provided on S1 and/or S2, though such
a coating can be provided anywhere on the IGU. The low-emissivity
coating may be provided on the same or different surface as the
patterned layer. The low-emissivity coating may also be provided on
the same or different surface as the electrochromic layer. So long
as the low-emissivity coating is outboard of the electrochromic
layer, heat gain through the window related to heating of the
electrochromic device itself can be minimized. In a particular
embodiment, the patterned layer is outboard of a low-emissivity
coating, which is outboard of the electrochromic device. Many other
configurations are possible.
[0091] In certain embodiments, the reduction in heat gain
efficiency related to having the electrochromic device on S3 or S4
may be offset by other factors, making placement of the
electrochromic device on S3 and/or S4 more attractive. In some
embodiments, it is beneficial to have the electrochromic device
provided on the interior of the IGU, on S2 and/or S3. This
structure ensures that the electrochromic device is protected from
the elements. Alternatively or in addition, an electrochromic
device may be provided on the outer surfaces of the IGU, e.g., on
S1 and/or S4, as desired for a particular application. Where this
is the case, a protective layer may be provided over the
electrochromic device to protect the electrochromic device from
damage. One such protective layer, e.g., if the EC device is on S4,
can be an additional inboard lite, either laminated to S4 or
provided with an inert gas barrier and spacer between S4 and the
additional lite to form a triple pane IGU as described above.
[0092] With respect to the relative position of the patterned layer
and the electrochromic device, a number of possibilities are
available. In some embodiments, the patterned layer is positioned
closer to the exterior environment and the electrochromic layer is
positioned closer to the building interior (i.e., the patterned
layer is outboard of the electrochromic device). This configuration
may be beneficial in that the pattern on the patterned layer will
be visible to birds regardless of the optical state of the
electrochromic device. Because the electrochromic device is not
positioned between the bird and the patterned layer in these
examples, the electrochromic device can't prevent the bird from
seeing the patterned layer. In the examples of FIGS. 4A-4L, an IGU
includes a first lite 402a and a second lite 402b, with an
electrochromic stack 420 and a patterned layer 405 provided
somewhere in/on the IGU. In the examples of FIGS. 4M-4X, the IGUs
further include a third lite 402c, thereby forming triple paned
IGUs. The lites 402a-402c and other layers are shown extending
into/out of the page, and only a portion of the IGU is shown (e.g.,
spacers, frames, and other components are omitted). As used in
relation to FIGS. 4A-4X, an electrochromic stack 420 (sometimes
also referred to as an electrochromic device, electrochromic
coating, etc.) may refer to an entire electrochromic device
including, e.g., a first conductive layer, a cathodically coloring
electrochromic layer, an optional ion conducting layer, an
anodically coloring (or optically passive) counter electrode layer,
and a second conductive layer. However, the electrochromic stack
420 may also refer to a more limited portion of the electrochromic
stack including just the cathodically coloring electrochromic
layer, the optional ion conducting layer, and the anodically
coloring (or optically passive) counter electrode layer, with the
location of the conducting layers not being specified but
understood to be in functionally appropriate locations. Other
layers (e.g., defect mitigating layers, low-emissivity coatings,
etc.) may also be present.
[0093] In the example of FIG. 4A, both the patterned layer 405 and
the electrochromic stack 420 are provided on S1, with the patterned
layer 405 provided on top of the electrochromic stack 420 (and
therefore outboard of the electrochromic stack 420). In another
example, the patterned layer 405 is provided on S1, and the
electrochromic stack 420 is provided on any one or more of S2, S3,
and S4. FIG. 4B illustrates an example where the patterned layer
405 is on S1 and the electrochromic stack 420 is on S2. In another
example, the patterned layer 405 is provided on S1 and/or S2, and
the electrochromic stack 420 is provided on S2, S3, and/or S4, with
the patterned layer 405 being positioned outboard of the
electrochromic stack. FIG. 4C illustrates an example where both the
patterned layer 405 and the electrochromic stack 420 each provided
on S2, with the patterned layer 405 outboard of the electrochromic
stack 420.
[0094] In another embodiment, the patterned layer 405 is provided
on S1 and/or S2, and the electrochromic stack 420 is provided on S3
and/or S4. FIG. 4D provides one such example, showing the patterned
layer 405 on S2 and the electrochromic stack 420 on S3. FIG. 4D
also shows a low-emissivity coating 425 positioned on S1. As stated
above, a low-emissivity coating may be provided at a number of
locations, often but not necessarily outboard of an electrochromic
layer. In a particular embodiment, the patterned layer is provided
on S1 and/or S2, and the electrochromic device is provided on S3.
In another embodiment shown in FIG. 4E, both the patterned layer
405 and the electrochromic stack 420 are provided on S3, with the
patterned layer 405 being positioned outboard of the electrochromic
stack 420. In another embodiment, the patterned layer 405 may be
provided on S1, S2, and/or S3, and the electrochromic stack 420 is
provided on S4. In yet another embodiment, both the patterned layer
405 and the electrochromic stack 420 may be provided on S4, with
the patterned layer 405 being positioned outboard of the
electrochromic stack 420, as shown in FIG. 4F. In various
embodiments, each of the patterned layer 405 and the electrochromic
stack 420 may be provided on any one or more of S1, S2, S3, and S4,
with the patterned layer 405 being provided outboard of the
electrochromic stack 420. Only some of the listed configurations
are shown explicitly in the figures, though all disclosed
configurations are considered to be within the scope of the present
embodiments.
[0095] FIGS. 4A-4F present embodiments where the patterned layer
405 is positioned outboard of the electrochromic stack 420. In
other embodiments, for example as shown in FIGS. 4G-4L, these
relative positions may be reversed such that the patterned layer
405 is inboard of the electrochromic stack 420. In some such
embodiments, there is a risk that when the electrochromic stack 420
is in a relatively more tinted state, the tinted electrochromic
device will prevent a bird flying outside from seeing/perceiving
the patterned layer (since the electrochromic device is outboard of
the patterned layer and can therefore block the patterned layer
from the bird's perspective).
[0096] This risk is minimized when the electrochromic device's
available optical states render the electrochromic window either
(a) sufficiently opaque/tinted (or other optical characteristic)
such that the bird can perceive the presence of the window, or (b)
transparent in the human-visible spectrum, but patterned in the UV
spectrum such that the bird can perceive the presence of the
window. In (a), the window may be sufficiently dark that a bird
perceives it as a wall or other structure that can't be flown
through. In (b), the window may appear clear to humans, but
patterned to birds, such that the birds won't try to fly through
the window. In a number of embodiments, an electrochromic window is
configured to achieve two or more optical states, each of which
achieve at least one of (a) or (b). In certain embodiments, an
electrochromic window is configured to achieve a three or more
optical states, with one (or more) optical state achieving (b) and
the remaining optical states achieving (a). In a particular
example, an optical device is configured to achieve three optical
states including a first state that appears transparent to humans
and patterned to birds, a second state that appears moderately
tinted to both humans and birds, and a third state that appears
highly tinted to both humans and birds. In each of the second and
third state, the window is sufficiently dark and perceptible such
that birds do not try to fly through the window. The reflectivity,
transmissivity, and other optical properties of the window can be
tuned to ensure this result, for example by providing one or more
anti-reflective coatings on the electrochromic window (e.g., on S1
or another surface). This technique can be applied regardless of
the relative positions of the patterned layer and the
electrochromic stack, though it may be most beneficial in cases
where the electrochromic stack is outboard of the patterned
layer.
[0097] Returning to the embodiments of FIGS. 4G-4L, each of the
patterned layer 405 and the electrochromic stack 420 may be
provided on any one or more of S1, S2, S3, and S4, with the
patterned layer 405 being provided inboard of the electrochromic
stack 420. A number of examples are shown in FIGS. 4G-4L, which
correspond to FIGS. 4A-4F, respectively, with the positions of the
patterned layer 405 and the electrochromic stack 420 reversed. One
difference between FIG. 4D and the corresponding FIG. 4J is that no
low-emissivity coating 425 is shown in FIG. 4J. In this embodiment,
the electrochromic device is provided on the external pane, so
there is less concern about heating the interior due to a warm
electrochromic device layer, and therefore less benefit to
including the low-emissivity coating. As with the examples above,
only some of the available configurations are explicitly shown in
the figures, though all disclosed configurations are considered to
be within the scope of the present embodiments. Further, any
information presented above with respect to FIGS. 4A-4F regarding
the relative positions of the patterned layer 405 and the
electrochromic stack 420 may be reversed in embodiments where the
patterned layer is provided inboard of the electrochromic
stack.
[0098] FIGS. 4M, 4N, and 4P-4X present embodiments of triple pane
IGUs that include a third lite 402c in addition to the first and
second lites 402a and 402b, respectively. The IGUs further include
a patterned layer 405 and an electrochromic stack 420. From the
outermost surface inward, the surfaces are labeled S1, S2, S3, S4,
S5, and S6. In the embodiments of FIGS. 4M, 4N, and 4P-4X, the
electrochromic stack (device coating) 420 is positioned on either
S3 or S4. In other words, in these embodiments, the electrochromic
stack 420 is positioned on the middle lite (though it may be
provided elsewhere in other embodiments). Further, the patterned
layer 405 is positioned outboard of the electrochromic stack 420
(though this may be reversed in some cases). While FIGS. 4M, 4N,
4P, and 4Q all show the patterned layer 405 on the first lite 402a
(the most outboard lite), this is not always the case. In similar
embodiments, the patterned layer 405 may be positioned on any one
or more of the surfaces S1-S6. FIG. 4R shows one such embodiment,
with the patterned layer 405 provided on S3 and the electrochromic
device 420 provided on S4. As is the case with a dual pane IGU, the
patterned layer may be positioned on an electrochromic lite (e.g.,
on the same surface as an electrochromic stack or on the other
primary surface of the electrochromic lite) or on a different lite
that is not electrochromic. In various cases where a triple pane
IGU construction is used, the electrochromic stack may be
positioned outboard of at least one pane and at least one pocket of
gas, such that the gas pocket can act as a thermal barrier to
reduce heat transfer from a warmed electrochromic stack into the
building interior.
[0099] FIGS. 4S-4X present embodiments of triple pane IGUs that
further include a low-emissivity coating 425. The low-emissivity
coating 425 may be provided outboard of the electrochromic stack
420, thereby minimizing the degree to which the electrochromic
stack 420 is heated by solar energy, and relatedly, minimizing the
degree of heat transfer into the building interior. While FIGS.
4S-4X each show the low-emissivity coating 425 on S1 or S2 of the
first lite 402a, and also show the electrochromic stack 420 on S3
or S4 of the second lite 402b, this is not always the case. In some
other cases, a low-emissivity coating 425 and/or electrochromic
stack 420 may be provided on a different (or additional) lite.
Similarly, the patterned layer 405 may be positioned in a number of
possible locations, as described herein. While FIGS. 4S-4X each
show the patterned layer 405 outboard of the electrochromic stack
420, this may be reversed in some other embodiments.
[0100] FIG. 4S depicts an embodiment where the low-emissivity
coating 425 is provided on S2, the patterned layer 405 is provided
on S3, and the electrochromic stack 420 is provided on S4. FIG. 4T
depicts a similar embodiment where the low-emissivity coating 425
is provided on S1. FIG. 4U presents an embodiment where the
low-emissivity coating 425 is provided on S1, the patterned layer
405 is provided on S2, and the electrochromic stack 420 is provided
on S4. FIG. 4V presents a similar embodiment where the
electrochromic stack 420 is provided on S3. FIG. 4W presents an
embodiment where the patterned layer 405 is provided on S1, the
low-emissivity coating 425 is provided on S2, and the
electrochromic stack 420 is provided on S3. FIG. 4X presents a
similar embodiment where the electrochromic stack 420 is provided
on S4.
[0101] In certain implementations, the patterned layer and/or
electrochromic stack may be provided at a different location on a
triple paned IGU. FIGS. 4M, 4N, and 4P-4X illustrate only a limited
number of possibilities. The patterned layer(s), the electrochromic
stack(s), as well as other layers such as low-emissivity layer(s),
anti-reflective layer(s), etc., may each be provided on any one or
more of the surfaces S1-S6, with different advantages and
disadvantages for each configuration. Any information related to
the relative position of these layers in a dual pane IGU (or other
construction) as described herein may also apply to embodiments
where a triple pane IGU is used.
[0102] FIG. 4Y depicts a double pane IGU, 436, where the outboard
lite is a laminate of an electrochromic lite, 402b, and a
non-electrochromic lite, 402a, with bird friendly patterning
thereon. In this example, the inboard lite, 402c, of IGU 436 may or
may not have coatings, such as low-E, antireflective, UV
scattering, and/or UV reflective coatings. The electrochromic
coating, 420, is on S4 of the construct. The outboard lite of IGU
436 is a laminate of lite 402b and 402a, with surfaces S2 and S3
(not labeled for the sake of clarity) facing one another.
Lamination adhesive, 435, may be of the resin lamination type or
other lamination adhesive. Adhesive 435 may optionally include UV
reflective and/or scattering particles or other UV optical
properties. In such embodiments, if adhesive 435 has UV enhanced
optical properties to make the IGU 436 visible to birds, then bird
friendly patterning, 405, is optional. In certain embodiments, bird
friendly patterning 405 is a film as described herein that is
applied to lite 402a, e.g., a UV reflective or absorptive coating,
a glass frit coating, a paint or the like. In other embodiments,
bird friendly pattering 405 is etched, sandblasted or otherwise is
part of lite 402a, i.e., not an applied coating but rather features
of the lite itself. Lite 402a may be glass or plastic, thick or
thin. In certain embodiments, lite 402a is thin flexible glass.
Exemplary thin flexible glass includes thin and durable glass
materials, such as Gorilla.RTM. Glass (e.g., between about 0.5 mm
and about 2.0 mm thick) Willow.TM. Glass, and Eagle.TM. Glass, each
commercially available from Corning, Incorporated of Corning N.Y.
In one embodiment, the flexible glass is less than 1 mm thick, in
another embodiment the flexible glass is less than 0.7 mm thick, in
another embodiment the flexible glass is less than 0.5 mm thick, in
another embodiment the flexible glass is less 0.3 mm thick, and in
another embodiment the flexible glass is about 0.1 mm thick. In
certain embodiments, the thin flexible glass may be less than 0.1
mm thick. Such substrates can be used in roll-to-roll processing to
apply the glass to the electrochromic lite during lamination. Also,
with thin glass, "peel and stick" adhesive technologies are easily
implemented.
[0103] The lamination can be done after an IGU is constructed;
e.g., using lites 402b and 402c a double pane IGU is fabricated,
then lite 402a is laminated to lite 402b of the IGU. Lamination of
a lite to an existing electrochromic IGU is described in U.S. Pat.
No. 8,164,818, titled, "Electrochromic Window Fabrication Methods,"
which is herein incorporated by reference in its entirety.
Advantages to lamination after IGU formation is that choice of
lamination partner, e.g., lite 402a, can be made post IGU
fabrication. This allows for greater flexibility in process flow,
since the IGU fabrication line can undergo few if any changes; lite
402a is applied downstream. In other embodiments, lites 402a and
402b are laminated together and then the resulting laminate used,
along with lite 402c, to make IGU 436.
Patterning Through Thickness Variations within a Layer
[0104] One method for patterning a layer within an electrochromic
device is to use a layer having varying thickness, where the
different thicknesses provide a contrast that birds can see, but
humans cannot see, at least not easily. Such a method may be used
on any layer within an electrochromic device that provides a visual
contrast at different layer thicknesses that birds can appreciate.
Various embodiments herein are presented in the context of a
pattern formed in a buffer layer/DMIL made of titanium oxide,
though the techniques herein may also be applied to other layers in
the device.
[0105] FIG. 4Z provides a chart showing a model of the reflectance
(%) vs. wavelength (nm) where different thicknesses of titanium
oxide are provided on an outer surface of a pane of an IGU. The
modeled reflectance is the R1 reflectance, which relates to the
reflection of the IGU in the direction of the exterior of the
building. In other words R1 is the reflection off of the
exterior-facing surface of the exterior pane (often referred to as
the S1 surface). The objects that were modeled in relation to FIG.
4Z were IGUs that included an electrochromic stack with a titanium
oxide layer deposited on an outer surface of the exterior pane
(i.e., on S1, the IGU surface that would be closest to a bird
located outside). The different thicknesses of titanium oxide
result in substantial differences in reflectance, particularly at
low wavelengths such as in the UV spectrum. Within the spectrum
visible by humans (about 400-700 nm), the differences in
reflectance are smaller, especially above about 475 nm. Table 1
shows the change in reflectance compared to a baseline case where
no TiO.sub.x is used, for both reflectance at 370 nm (a UV
wavelength easily viewable by birds but not by humans), and for
photopic reflectance visible by humans.
TABLE-US-00001 TABLE 1 % Change in Reflectance at % Change in
Photopic 370 nm, Compared to Reflectance, Compared to TiO.sub.x
Thickness Baseline Baseline 5 nm 55% 5% 10 nm 153% 18% 15 nm 258%
39% 20 nm 347% 63%
[0106] As shown in Table 1, the changes in reflectance in the UV
are substantially greater than the changes in photopic reflectance,
meaning that a pattern etched into a TiO.sub.x layer will be much
more noticeable to birds than to humans. As such, birds can
perceive the pattern and understand that they can't fly through the
window, while at the same time human occupants enjoy a relatively
clear (unpatterned) view through the window.
[0107] While the results in FIG. 4Z relate to an IGU with a
titanium oxide layer that is positioned on the outside of an IGU,
the results suggest that TiO.sub.x thickness can be tuned to create
regions of contrasting reflectance in the UV (wherever such
TiO.sub.x layers are provided). For example, TiO.sub.x regions
having a first thickness would show greater reflectance and
TiO.sub.x regions having a second thickness would show less
reflectance. The first thickness may be less than or greater than
the second thickness. A bird could perceive this contrast (and
therefore the pattern on the window) and recognize that it cannot
fly through the window.
[0108] The varying thickness of the patterned layer may be achieved
in a number of ways. In one embodiment, the layer is deposited at a
uniform thickness, and portions of the layer are etched away to
form the pattern. In one embodiment, the entire thickness of the
patterned layer is etched through, as discussed below in relation
to FIG. 5A. In such cases, the etching process may expose an
underlying layer positioned below the patterned layer. In another
embodiment, only a portion of the thickness of the patterned layer
is etched through, as discussed below in relation to FIG. 5B.
[0109] FIG. 5A illustrates a cross-sectional view of an
electrochromic device according to certain embodiments. FIG. 6A
presents a flow chart for a method of forming a portion of the
electrochromic device shown in FIG. 5A. With respect to FIG. 5A,
the device includes a substrate 502, a first conductive layer 504,
a patterned bird friendly layer 505, an electrochromic stack 506,
and a second conductive layer 514. The patterned layer 505 is
discontinuous in this example. The electrochromic stack 506 in
FIGS. 5A-5G includes at least a cathodically coloring
electrochromic layer and an anodically coloring (or optically
passive) counter electrode layer (and, as opposed to the
electrochromic stack 120 of FIG. 1, does not include the conductive
layers, which are shown separately). In various embodiments
electrochromic stack 506 also includes an ion conducting layer or
ion conducting region. Such a region may be deposited along with
and between the electrochromic and counter electrode layers, or it
may form at the interface of such layers in later processing steps,
as discussed further in U.S. Pat. No. 8,764,950, which is herein
incorporated by reference in its entirety.
[0110] In order to fabricate the device of FIG. 5A, the method 600
of FIG. 6A may be used. The method 600 begins at operation 601
where a substrate 502 is received with a conductive layer 504
thereon. In a similar embodiment, the method may include depositing
the conductive layer 504 on the substrate 502. Conductive layers
and deposition thereof is further discussed in U.S. patent
application Ser. No. 12/645,111, filed Dec. 22, 2009, and titled
"FABRICATION OF LOW DEFECTIVITY ELECTROCHROMIC DEVICES," which is
herein incorporated by reference in its entirety. Next, at
operation 603, the layer to be patterned is deposited. This layer
may be referred to as a pre-patterned layer, and will eventually
form patterned layer 505 in FIG. 5A. The pre-patterned layer may be
deposited to a relatively uniform thickness, and then portions of
the film may be removed. In some cases, the thickness of the
pre-patterned layer (where deposited) may be between about 5-200
nm, or between about 30-80 nm. In some such cases, the thickness of
the pre-patterned layer may be at least about 7 nm (where
deposited). In these or other cases, the thickness of the
pre-patterned layer may be about 200 nm or less (where deposited).
In a particular embodiment the pre-patterned layer may be titanium
oxide, though other materials may also be used as appropriate.
[0111] Next, at operation 605, the pre-patterned layer is etched to
form the patterned layer 505. The pattern formed may in various
embodiments have one or more of the characteristics described
above, for example the dimensions listed above and/or the designs
shown in FIGS. 3B-3H. In the embodiment of FIG. 5A, the entire
thickness of the pre-patterned layer is etched through, thereby
exposing the underlying first conductive layer 504. The etching may
occur through laser etching methods, chemical etching methods,
abrasive etching methods, etc.
[0112] After the etching operation 605, one or more optional
cleaning operations (not shown in FIG. 6A) may take place to remove
any residues or other undesirable materials. Such cleaning may
occur through various available methods including, but not limited
to, flat plate washers, which may be used to polish the materials
if desired.
[0113] Next, the electrochromic stack 506 is deposited in operation
607. In some embodiments, the stack 506 is deposited to include at
least a cathodically coloring electrochromic layer, an ion
conductor layer, and an anodically coloring (or optically passive)
counter electrode layer. In some other embodiments, the stack 506
is deposited to include at least a cathodically coloring
electrochromic layer and an anodically coloring (or optically
passive) counter electrode layer, which may be in direct physical
contact with one another. In these implementations, an ion
conducting region may form between the electrochromic and counter
electrode layers, for example through multistep thermal
conditioning (MTC) as described in U.S. Pat. No. 8,764,950, which
is incorporated by reference above. Deposition of the various
layers in the electrochromic stack 506 is further discussed in U.S.
patent application Ser. No. 12/645,111, which is incorporated by
reference above. After the electrochromic stack 506 is deposited,
the second conductive layer 514 is formed in operation 609. The
multistep thermal conditioning may occur (if at all) after the
second conductive layer 514 is deposited.
[0114] In another method, operation 603 involves selectively
depositing the patterned layer 505 in regions where it is desired.
In order to avoid depositing the patterned layer 505 in regions
where it is not desired, such regions may be masked in operation
603. Operation 605 may then be eliminated. A series of masks may be
used in some cases. In one embodiment, a mask may be rotated and/or
otherwise re-positioned between subsequent depositions performed on
the same substrate.
[0115] FIG. 5B presents a cross-sectional view of another
embodiment of an electrochromic device that is patterned to be bird
friendly. This embodiment is similar to FIG. 5A, and for the sake
of brevity only the differences will be described. In FIG. 5B, the
patterned layer 505b is continuous and includes two different
thicknesses. In certain embodiments where the patterned layer
includes different thicknesses to provide the contrast visible by
birds, the difference in thickness may be at least about 30 nm, or
at least about 90 nm. In some such cases, the thickness difference
may be about 40 nm or less, or about 100 nm or less. In some
embodiments, a thicker portion of the patterned layer may be at
least about 2.times. as thick as a thinner portion of the patterned
layer (e.g., at least about 3.times. as thick). The thickness
difference may result in an average reflectance difference of at
least about 5% when considering wavelengths between about 300-400
nm. The thickness difference may also result in an average
reflectance difference below about 1% when considering wavelengths
between about 400-700 nm.
[0116] One reason that one of skill might choose the design of FIG.
5B over the design of FIG. 5A is that the patterned layer 505 may
also be used as a defect-mitigating-insulating layer. Where this is
the case, it is desirable that the patterned layer 505
substantially covers the first conductive layer 504 in a continuous
manner. This continuous coverage can help form devices with fewer
defects and a lower risk of electrical shorts forming within the
device.
[0117] The method 600 of FIG. 6A may be used to form the
electrochromic device shown in FIG. 5B. The method will be very
similar to that described in relation to FIG. 5A, except that
operation 605 is terminated before the layer is completely etched
through. As noted above, operation 605 may be eliminated in cases
where operation 603 involves selective deposition to form the
pattern. For instance, operation 603 may include a first deposition
that deposits material at a uniform thickness, followed by a second
deposition that selectively deposits additional material where it
is desired. In some cases, a mask may be used as described above to
achieve the selective deposition.
Patterning through Composition/Material Variations
[0118] In a number of embodiments, recesses in an etched patterned
layer may be filled with one or more materials. For instance, a
buffer layer may be provided to fill these recesses. The material
that fills the recesses may also deposit over non-recessed portions
of the patterned layer. The pattern formed in the patterned layer
may be visible by birds either through optical contrasts arising
from thickness differences within the patterned layer and/or within
the buffer layer, and/or it may be visible through optical
contrasts arising from different optical properties of the material
used for the patterned layer vs. the material used for the buffer
layer. In some cases, a buffer layer as described in relation to
FIGS. 5C-5G may be considered a second patterned layer or index
layer (and may or may not have properties similar to other buffer
layers used in the context of electrochromic windows).
[0119] The material chosen to fill the recesses in the patterned
layer may be chosen to have certain properties. In some cases, this
material has a relatively high resistivity, for example between
about 1 and 5.times.10.sup.10 Ohm-cm. The material may also have a
different index of refraction compared to the material of the
patterned layer (at least in UV). In some cases, the material used
to fill recesses in the patterned layer is one that has a
relatively low index of refraction (n), for example below about 1.5
in some cases. In a particular example, the material used to fill
recesses in the patterned layer is silicon oxide. In another
example, the material used to fill recesses in the patterned layer
may be the same material at a different relative composition
compared to the material used for the patterned layer. For
instance, both the patterned layer and the material used to fill
recesses in the patterned layer may be titanium oxide provided at
different stoichiometry.
[0120] FIG. 7A presents a graph depicting the reflectance (%) vs.
wavelength (nm) modeled for two IGUs that include an electrochromic
device stack and a layer of either 50 nm thick TiO.sub.x or 50 nm
thick SiO.sub.x. The reflectance modeled relates to the R1
reflectance, which represents the reflection off of the exterior
pane (which would be closest to a bird). The TiO.sub.x/SiO.sub.x
layers were modeled as being located between a conductive oxide
layer and the electrochromic stack. The electrochromic device was
modeled to be in its clearest state. Notably, at about 370 nm, the
TiO.sub.x and SiO.sub.x materials show about a 60% difference in
their reflectance, which would be easily visible to most birds. By
contrast, when considering the difference in the photopic
reflection (reflection in the spectrum visible by humans), the
TiO.sub.x and SiO.sub.x materials show about an average of 32%
difference in their reflectance. In other words, the change in
reflectance is about twice as high at 370 nm (easily viewable by
birds) than at wavelengths viewable by humans. Though the graph
shows various ripples at different wavelengths, these ripples are
not particularly important because humans and birds do not perceive
individual wavelengths, rather, humans and birds see an average of
the transmitted wavelengths, weighted appropriately for
sensitivity. For instance, birds will see an average of the
wavelengths between about 300-700 nm, while humans will see an
average of the wavelengths between about 400-700 nm.
[0121] FIG. 5C presents a cross sectional view of another
embodiment of an electrochromic device that is patterned to be bird
friendly. This embodiment is similar to that shown in FIG. 5A, and
only the differences will be addressed.
[0122] In FIG. 5C, the device includes a discontinuous patterned
layer 505c, much like the patterned layer 505 of FIG. 5A.
Positioned above the patterned layer 505c is a buffer layer 520.
This buffer layer 520 may be made of a material that contrasts with
the patterned layer 505c. For instance, buffer layer 520 may be
made of a material that has a different refractive index than
patterned layer 505c. Differences in
reflectance/absorbance/transmittance/related optical properties
between the buffer layer 520 and the patterned layer 505c can help
make the window visible to birds.
[0123] FIG. 6B is a flow chart depicting a method of forming the
electrochromic device shown in FIG. 5C. The method 620 in FIG. 6B
is similar to the method 600 of FIG. 6A, and only the differences
will be discussed. In particular, the method 620 includes an
additional step, operation 606, where the buffer layer 520 is
deposited and optionally flattened. The buffer layer 520 is
deposited after the pre-patterned layer is etched to form the
patterned layer 505c. In some embodiments, the partially fabricated
device may be cleaned after the patterned layer 505c is formed from
the pre-patterned layer, and before the buffer layer 520 is formed.
The buffer layer 520 may deposit in areas where the pre-patterned
layer was etched away. The buffer layer 520 may also deposit over
areas where the patterned layer 505c remains.
[0124] Because the buffer layer 520 is deposited over an uneven
surface, it may be beneficial in certain embodiments to planarize
the buffer layer before further processing, to thereby form a flat,
uniform layer upon which the electrochromic stack 506 can be
deposited. In some other embodiments this planarizing step may be
omitted. Such planarizing may occur through chemical mechanical
polishing (CMP), etching (e.g., with plasma) and the like.
[0125] The buffer layer 520 may be made of a variety of materials.
In some embodiments, the buffer layer 520 is suitable as a
defect-mitigating-insulating layer. For instance, the buffer layer
may be a material having an electronic resistivity between about 1
and 5.times.10.sup.10 Ohm-cm. By using such a material in
combination with a patterned layer 505c, the risk of forming
defective devices can be minimized.
[0126] In some implementations, at least one of the patterned layer
505c and the buffer layer 520 is made of titanium oxide. In some
cases, the other of the patterned layer 505c and the buffer layer
520 is made of silicon oxide. The silicon oxide may be Sift in some
cases, though other relative compositions and materials may also be
used. In a particular embodiment, the patterned layer 505c is
titanium oxide and the buffer layer 520 is silicon oxide.
[0127] In various embodiments, the buffer layer 520 may be
deposited up to a height that is at least about as high as the
patterned layer 505c. In some cases, as shown in FIG. 5C, the
buffer layer 520 may be deposited to a height that is above the
patterned layer 505c, thereby forming a continuous buffer layer
520.
[0128] As discussed with relation to the method 600 of FIG. 6A, the
method 620 of FIG. 6B may be modified such that operation 603
involves selectively depositing the patterned layer in areas where
it is desired, for example through use of one or more masks.
Operation 605 may then be eliminated.
[0129] FIG. 5D illustrates an additional embodiment of an
electrochromic device that is patterned to be bird friendly. This
embodiment combines the patterned layer 505b of FIG. 5B (which was
etched only part way through) with the buffer layer 520 of FIG. 5C.
This device could be fabricated using the method 620 of FIG.
6B.
[0130] FIG. 5E depicts another example embodiment of an
electrochromic device that is patterned to be bird friendly. This
embodiment is similar to that shown in FIG. 5D, except that the
buffer layer 520e is discontinuous. The device shown in FIG. 5E may
be fabricated using the method 620 of FIG. 6B in some cases. For
instance, in operation 605 the pre-patterned layer is partially
etched through to form the patterned layer 505b. An optional
cleaning operation may occur, followed by operation 606 where the
buffer layer is deposited. The buffer layer may be deposited over
all portions of the patterned layer 505b, including in areas where
the pre-patterned layer was etched away. The buffer layer 520e may
then be flattened/polished to thereby remove the buffer layer 520e
in regions where the patterned layer 505b is thickest. Some portion
of the patterned layer 505b may also be removed during this
flattening process.
[0131] FIG. 5F shows yet another example embodiment of an
electrochromic device that is patterned to be bird friendly. This
embodiment is similar to that shown in FIG. 5E, except that both
the patterned layer 505f and the buffer layer 520f are
discontinuous. The method 620 of FIG. 6B can be used to fabricate
the device shown in FIG. 5F. In such an implementation, operation
605 involves etching through the entire thickness of the
pre-patterned layer to form the patterned layer 505f. The partially
fabricated device may then be cleaned, and then the buffer layer
520f may be deposited at operation 606. The buffer layer 520f may
deposit on all regions of the patterned layer 505f before being
removed through flattening/polishing in areas where the patterned
layer 505c is present.
[0132] In FIGS. 5A and 5B, the contrast visible by birds may be
generated due to having different thicknesses within the patterned
layer. In such embodiments, the patterned layer may be made of a
material that exhibits contrasting visual properties (particularly
at UV wavelengths as described above) at different thicknesses. In
FIGS. 5C-5F, the contrast visible by birds may be generated as a
result of (a) differences in thickness within the patterned layer,
where the patterned layer exhibits contrasting properties at
different thicknesses, (b) differences in thickness in the buffer
layer, where the buffer layer exhibits contrasting properties at
different thicknesses, (c) differences in optical properties
between the patterned layer and the buffer layer, or (d) some
combination thereof. In FIGS. 5C-5F, the patterned layer and the
buffer layer may together form the pattern that is visible by
birds.
[0133] FIGS. 5A-5F depict embodiments where a patterned layer is
positioned between a first conductive layer 504 and the
electrochromic stack 506. However, the patterned layer may also be
positioned at other locations, for example between the substrate
502 and the conductive layer 504, between the electrochromic stack
506 and the second conductive layer 514, and/or on the outer
surface of the substrate 502 (or on an interior or exterior facing
surface of another substrate, for example a second substrate
provided in an IGU). Any of the techniques and/or configurations
related to patterned and/or buffer layers shown and described in
relation to FIGS. 5A-5F may also be used to form a patterned layer
(and buffer layer, if appropriate) in these alternative locations.
For the sake of brevity, only one such example is shown in the
figures.
[0134] FIG. 5G shows an embodiment of an electrochromic device
patterned to be bird friendly, where a discontinuous patterned
layer 505g is provided with a continuous buffer layer 520g, each
provided between the substrate 502 and the first conductive layer
504. This embodiment is similar to that shown in FIG. 5C, except
for the location of the patterned layer 505g and buffer layer 520g.
The electrochromic device in FIG. 5G also includes a second buffer
layer 521 positioned between the first conductive layer 504 and the
electrochromic stack 506, though this layer may be omitted in some
embodiments.
[0135] As discussed further below, the window may also be made hazy
in the UV, which may render it easier for birds to see. The
discussion below focuses on embodiments where the entire window is
made hazy. However, such haziness can also be formed in a pattern,
for example as described in relation to FIGS. 3B-3H. The
contrasting pattern features in this case may include the
relatively more hazy portions and the relatively less hazy
portions. Both global window haziness and patterned window
haziness, particularly where such haziness is more visible to birds
than to humans, are considered to be within the scope of the
disclosed embodiments.
Methods of Making an Electrochromic Window Appear Hazy
[0136] Another method of reducing the risk that a bird will try to
fly through a window is to make the window appear hazy. Where such
haziness is relatively strong at wavelengths visible by birds (but
not by humans) and relatively weak at wavelengths visible by
humans, the result is high quality bird friendly glass. Haze may be
provided as a pattern having a strong contrast in the bird-visible
ultraviolet region. Transmission haze and/or reflection haze may be
utilized in various embodiments. Transmission haze is the forward
scattering of light from the surface of a nearly clear substrate
viewed in transmission. Light scattered back through the sample is
typically not included in transmission haze. Only light that is
scattered more than 2.5.degree. from the incident light is
considered to contribute to the haze. When measuring transmission
haze, the percentage of light diffusely scattered compared to the
total light transmitted is reported. Reflection haze is the spread
of the specular component of the reflected light from a glossy
surface. The light that is reflected from an object at an angle
equal to but opposite the incident light is the specular
component.
[0137] The appearance of haziness is a result of light scattering,
which is strongly dependent on wavelength. In particular, light
scattering intensity (I) is inversely proportional to the fourth
power of the wavelength (.lamda.) of light
(I.varies.1/.lamda..sup.4). This means that lower wavelengths tend
to scatter substantially more than higher wavelengths.
[0138] The structure of a material can affect whether or not light
will be scattered when traveling through the material. The degree
of crystallinity and the size of crystallites within a material are
relevant, as are the grain boundaries, microscopic pores, density
variations, or other defects (if present). The length scale of
these structural features relative to the wavelength of light being
scattered is relevant. As such, the morphology/structure of a given
layer can be tuned to provide scattering in UV that renders the
window visible to birds but transparent/clear to humans.
[0139] One way to tune the morphology of a layer is to control the
conditions at which the layer is deposited to achieve a particular
crystallinity. Factors such as substrate temperature during
deposition, sputter power, and chamber pressure can affect the
crystallinity of a deposited material.
[0140] Crystallinity depends on various deposition factors
including deposition temperature, deposition pressure, rate of
deposition, and method of deposition (e.g., evaporation, magnetron,
chemical vapor deposition, etc.). Further details related to
process conditions that may be used in some embodiments are
provided in U.S. patent application Ser. No. 12/645,111, filed Dec.
22, 2009, and titled "FABRICATION OF LOW DEFECTIVITY WINDOWS,"
which is herein incorporated by reference in its entirety. In some
implementations, deposition conditions may be chosen to provide a
polycrystalline material having crystallites on the order of 50-200
nm.
[0141] Another way to configure a material to scatter in the UV is
to enhance the roughness of the layer. Such roughness can promote
scattering in UV when done at an appropriate length scale. In
various cases the scattering is not visible to humans.
Layers for Introducing Bird-Visible Haze
[0142] As noted above, in certain embodiments a layer in an
electrochromic window may be made globally or locally hazy (when
considering UV wavelengths) to minimize the risk that a bird will
try to fly through the window. The layer which is made hazy may be
a layer that is commonly included in electrochromic windows, or it
may be a new layer provided specifically for this purpose.
[0143] The haze-inducing layer may be positioned at any point
within or on an electrochromic IGU or other electrochromic window.
In a number of embodiments, the haze-inducing layer may be
positioned between panes of an IGU. For example, it may be
positioned between a substrate and a conductive layer, or between a
conductive layer and an electrochromic stack, or between a
conductive layer and a defect-mitigating-insulating layer, or
between a defect-mitigating insulating layer and an electrochromic
stack. In some other cases, a haze-inducing layer may be provided
outside the panes of the IGU, for example on an exterior surface of
an exterior pane (often referred to as S1) or on an interior
surface of an interior pane (often referred to as S4), or on an
additional substrate that may be laminated to either S1 or S4. In
various embodiments, the patterned layer 405 shown in FIGS. 4A-4Y
may be a haze-inducing layer, which may be uniformly hazy or
patterned to include hazy portions (visible to birds but not
humans) and non-hazy portions (transparent to both birds and
humans).
[0144] The layer that selectively appears hazy at UV wavelengths
may be made of a variety of materials. In some embodiments, a hazy
layer may be a thin film that is substantially transparent to UV.
The material of the hazy layer may be one having a polycrystalline
structure having a grain size on the order of about 50-200 nm.
[0145] In particular implementations, a hazy layer may be made of
titanium oxide, though various other materials listed herein may
also be used.
Other Bird Friendly Window Configurations
[0146] Various embodiments herein relate to electrochromic windows
that are designed to be visible to birds, for example by reflecting
a pattern and/or haze that is apparent at UV wavelengths. For the
sake of simplicity, the layer or layers that form a pattern and/or
haze which renders the window visible to birds may be referred to
as a bird friendly element. As noted above, one or more bird
friendly elements may be positioned at a number of different
locations on the window. Regardless of where the bird friendly
element is positioned, it should be visible to a bird through all
of the layers situated between the bird and the bird friendly
element.
[0147] For example, if a glass substrate used in an electrochromic
window absorbs a substantial amount of light at the wavelengths
that produce the visual contrast, such contrast may not be
transmitted through the substrate, and therefore may not actually
be visible to the birds. Therefore, the choice of substrate can
affect how bird friendly a window is.
[0148] Certain types of glass or other window substrates may be
better suited for bird safe windows than other types of substrates.
Substrates that absorb more UV, particularly in the UVA range, are
generally less suitable.
[0149] FIG. 7B presents a graph showing the transmission (%) and
reflectance (%) vs. wavelength (nm) for two types of glass
substrates having a thickness of about 6 mm. One of the substrates
tested was glass having a mid-level content of iron (referred to in
FIG. 7B as midFe, typically a slightly greenish color), and the
other substrate tested was glass having an ultra-low content of
iron (referred to in Figure at as UL Fe, typically a slightly white
color). With respect to reflectance, two reflectances are shown, R1
and R2. R1 refers to the reflection off of the exterior surface
(often referred to as S1) and R2 refers to the reflection off of
the interior surface (often referred to as S2). FIG. 7B suggests
that glass having an ultra-low content of iron may be beneficial
compared to glass having a mid-level content of iron, at least
because the ultra-low iron content glass shows higher transmission
at all UV wavelengths.
[0150] Table 2 presents a table summarizing the results shown in
FIG. 7B.
TABLE-US-00002 TABLE 2 Average over 300-400 nm At 370 nm % T % R1 %
R2 % T % R1 % R2 Mid Fe Glass 64.4% 6.9% 6.8% 85.1% 7.8% 7.8% UL Fe
Glass 75.5% 7.8% 7.9% 89.1% 8.3% 8.3%
[0151] In certain embodiments, a bird friendly feature may include
a UV light source, e.g., emitting with a peak wavelength of between
about 320 nm and about 380 nm. The UV light source may be housed in
the framing system of the electrochromic window, e.g., in a frame
that houses an IGU. In some embodiments, a UV light source may be
incorporated into a spacer of an IGU. There may be one or more UV
light sources. The one or more UV light sources may project a
uniform UV light pattern into the edge of the glass or onto the
glass, or e.g., the light sources may project a non-uniform pattern
into and/or onto the glass. In certain embodiments, the one or more
UV light sources will project a pattern that is visible to birds
but not visible to humans. One or more UV light sources may be used
alone or in conjunction with UV absorbing and/or reflecting films
on the glass and/or in a lamination layer between the lites if
lamination is part of the IGU or other electrochromic window
construct. The projected and/or reflected pattern may be as
described herein, e.g., having less than 2 inches in the horizontal
spacing and less than 4 inches in the vertical spacing (e.g., see
FIG. 3A and associated description). The pattern can be generated
by the light source positioning, masking, or use of holographic
elements, e.g., etched or otherwise patterned in the lite
associated with the one or more light sources. The one or more UV
light sources may be on all the time or they may be sequenced,
pulsed or other similar technique to provide a dynamic pattern. The
one or more UV light sources may be used without any additional
structures or features on the electrochromic window and need not
obstruct the viewable area in any way. Also, the UV light
projecting system may work day and/or night. In one embodiment, the
one or more UV lights are LED lamps, e.g., commercially available
LED's with output of 365 nm are readily available from commercial
sources in strips and singly. In one embodiment, the one or more UV
light sources are combined with holographic lens arrays to project
a pattern onto the electrochromic window. The electrochromic window
may be tinted or not. In one embodiment, the UV light source is
powered by an onboard photovoltaic cell of the electrochromic
window, e.g., as described below, or is powered by the window
controller, or the UV light has its own power source, such as a
battery or a photovoltaic cell.
[0152] In certain embodiments, the UV light is attached to the
framing system of the electrochromic window after the window is
installed. It may be an add-on feature to existing EC windows. The
UV light may be tuned specifically to work with the electrochromic
film of the window in question, that is, retrofit of existing EC
window installations can be achieved by tuning the UV light's
output wavelength to be most effective with the electrochromic
windows with which the light will be deployed. In certain
embodiments, it is desirable to mount the UV light on the underside
of the top of the frame, so that the light is projected downward
and onto the electrochromic window, and e.g., the light will not
collect dust or debris and be obscured. The light may also be
provided on a side edge of the frame and/or on a bottom edge of a
frame, as desired. In cases where multiple light sources are
provided, they may be positioned proximate the same edge of an EC
window, or proximate different edges.
[0153] In certain embodiments, alone or in combination with other
embodiments described herein, an acoustical deterrent is included
with an electrochromic window. In one embodiment, the acoustical
deterrent operates in ultrasonic wavelengths. The acoustical
deterrent may be included in the framing system of the
electrochromic window or near it, but generally does not block the
viewable area of the window. In one embodiment, the acoustical
deterrent is powered by an onboard photovoltaic cell of the
electrochromic window, e.g., as described below, or is powered by
the window controller, or the acoustical deterrent has its own
power source, such as a battery or a photovoltaic cell.
[0154] In some embodiments, an electrochromic window may be
provided with a photovoltaic (PV) layer thereon. The PV layer may
be organic or silicon-based. The PV layer may itself be patterned
in a way that allows for birds to see the pattern while humans
cannot. In some other cases, a non-patterned PV layer is provided
in an electrochromic window having another patterned layer. The PV
layer may be electrically connected with a component
in/on/connected with the window to thereby allow the PV layer to
generate electricity and power the electrochromic window/window
controller. In one example, the (patterned or non-patterned) PV
film is provided on a sheet that is laminated to an electrochromic
IGU, for example on the exterior-facing surface of the exterior
pane (often referred to as S1).
[0155] An electrochromic window may also be provided with one or
more antennae patterned onto any of the surfaces of the window
(e.g., surfaces S1, S2, S3, and/or S4 on an IGU). Briefly, the
antennae may be formed by positioning thin conductive lines
surrounded by an insulator on one or more surfaces of the window.
The patterned antennae may serve the purpose of a bird safe layer
where it is fabricated in a way that is visible to birds. In one
example, a pattern (e.g., as described in relation to FIGS. 3B-3H)
may be etched (e.g., using a laser etching method or other etching
method) to form one or more antennae, where the pattern is formed
in a way that makes the window visible to birds. Further
information related to patterning antennae on an electrochromic
window is provided in PCT Patent Application No. PCT/US15/62387,
filed Nov. 24, 2015, and titled "WINDOW ANTENNA," which is herein
incorporated by reference in its entirety.
Integrated Deposition System
[0156] In various embodiments, an integrated deposition system may
be employed to fabricate electrochromic devices on, for example,
architectural glass. The electrochromic devices are used to make
IGUs which in turn are used to make electrochromic windows. The
term "integrated deposition system" means an apparatus for
fabricating electrochromic devices on optically transparent and
translucent substrates. The apparatus may have multiple stations,
each devoted to a particular unit operation such as depositing a
particular component (or portion of a component) of an
electrochromic device, as well as cleaning, etching, and
temperature control of such device or portion thereof. The multiple
stations are fully integrated such that a substrate on which an
electrochromic device is being fabricated can pass from one station
to the next without being exposed to an external environment.
[0157] Integrated deposition systems operate with a controlled
ambient environment inside the system where the process stations
are located. A fully integrated system allows for better control of
interfacial quality between the layers deposited. Interfacial
quality refers to, among other factors, the quality of the adhesion
between layers and the lack of contaminants in the interfacial
region. The term "controlled ambient environment" means a sealed
environment separate from an external environment such as an open
atmospheric environment or a clean room. In a controlled ambient
environment at least one of pressure and gas composition is
controlled independently of the conditions in the external
environment. Generally, though not necessarily, a controlled
ambient environment has a pressure below atmospheric pressure;
e.g., at least a partial vacuum. The conditions in a controlled
ambient environment may remain constant during a processing
operation or may vary over time. For example, a layer of an
electrochromic device may be deposited under vacuum in a controlled
ambient environment and at the conclusion of the deposition
operation, the environment may be backfilled with purge or reagent
gas and the pressure increased to, e.g., atmospheric pressure for
processing at another station, and then a vacuum reestablished for
the next operation and so forth.
[0158] In one embodiment, the system includes a plurality of
deposition stations aligned in series and interconnected and
operable to pass a substrate from one station to the next without
exposing the substrate to an external environment. The plurality of
deposition stations comprise (i) a first deposition station
containing one or more targets for depositing a cathodically
coloring electrochromic layer; (ii) a second (optional) deposition
station containing one or more targets for depositing an ion
conducting layer; and (iii) a third deposition station containing
one or more targets for depositing a counter electrode layer. The
second deposition station may be omitted in certain cases. For
instance, the apparatus may not include any target for depositing a
separate ion conductor layer.
[0159] Further, any of the layers of the stack may be deposited in
two or more stations. For example, where an electrochromic layer
and/or counter electrode layer is deposited to include two or more
sublayers, each of the sublayers may be deposited in a different
station. Alternatively or in addition, two or more sublayers within
a layer may be deposited within the same station, in some cases
using different targets in the same station. Targets of different
compositions may be provided at different portions of the station
to deposit the sublayers as desired. In another embodiment, a
dedicated station is provided to deposit each layer or sublayer
having a distinct composition.
[0160] The system may also include a controller containing program
instructions for passing the substrate through the plurality of
stations in a manner that sequentially deposits on the substrate
(i) an electrochromic layer, (ii) an (optional) ion conducting
layer, and (iii) a counter electrode layer to form a stack. In one
embodiment, the plurality of deposition stations are operable to
pass a substrate from one station to the next without breaking
vacuum. In another embodiment, the plurality of deposition stations
are configured to deposit the electrochromic layer, the optional
ion conducting layer, and the counter electrode layer on an
architectural glass substrate. In another embodiment, the
integrated deposition system includes a substrate holder and
transport mechanism operable to hold the architectural glass
substrate in a vertical orientation while in the plurality of
deposition stations. In yet another embodiment, the integrated
deposition system includes one or more load locks for passing the
substrate between an external environment and the integrated
deposition system. In another embodiment, the plurality of
deposition stations include at least two stations for depositing a
layer selected from the group consisting of the cathodically
coloring electrochromic layer, the ion conducting layer, and the
anodically coloring (or optically passive) counter electrode
layer.
[0161] In some embodiments, the integrated deposition system
includes one or more lithium deposition stations, each including a
lithium containing target. In one embodiment, the integrated
deposition system contains two or more lithium deposition stations.
In one embodiment, the integrated deposition system has one or more
isolation valves for isolating individual process stations from
each other during operation. In one embodiment, the one or more
lithium deposition stations have isolation valves. In this
document, the term "isolation valves" means devices to isolate
depositions or other processes being carried out one station from
processes at other stations in the integrated deposition system. In
one example, isolation valves are physical (solid) isolation valves
within the integrated deposition system that engage while the
lithium is deposited. Actual physical solid valves may engage to
totally or partially isolate (or shield) the lithium deposition
from other processes or stations in the integrated deposition
system. In another embodiment, the isolation valves may be gas
knifes or shields, e.g., a partial pressure of argon or other inert
gas is passed over areas between the lithium deposition station and
other stations to block ion flow to the other stations. In another
example, isolation valves may be an evacuated regions between the
lithium deposition station and other process stations, so that
lithium ions or ions from other stations entering the evacuated
region are removed to, e.g., a waste stream rather than
contaminating adjoining processes. This is achieved, e.g., via a
flow dynamic in the controlled ambient environment via differential
pressures in a lithiation station of the integrated deposition
system such that the lithium deposition is sufficiently isolated
from other processes in the integrated deposition system. Again,
isolation valves are not limited to lithium deposition
stations.
[0162] FIG. 8A, depicts in schematic fashion an integrated
deposition system 800 in accordance with certain embodiments. In
this example, system 800 includes an entry load lock, 802, for
introducing the substrate to the system, and an exit load lock,
804, for removal of the substrate from the system. The load locks
allow substrates to be introduced and removed from the system
without disturbing the controlled ambient environment of the
system. Integrated deposition system 800 has a module, 806, with a
plurality of deposition stations; an EC layer deposition station,
an IC layer deposition station and a CE layer deposition station.
In the broadest sense, integrated deposition systems need not have
load locks, e.g., module 806 could alone serve as the integrated
deposition system. For example, the substrate may be loaded into
module 806, the controlled ambient environment established and then
the substrate processed through various stations within the system.
Individual stations within an integrated deposition systems can
contain heaters, coolers, various sputter targets and means to move
them, RF and/or DC power sources and power delivery mechanisms,
etching tools e.g., plasma etch, gas sources, vacuum sources, glow
discharge sources, process parameter monitors and sensors,
robotics, power supplies, and the like.
[0163] FIG. 8B depicts a segment (or simplified version) of
integrated deposition system 800 in a perspective view and with
more detail including a cutaway view of the interior. In this
example, system 800 is modular, where entry load lock 802 and exit
load lock 804 are connected to deposition module 806. There is an
entry port, 810, for loading, for example, architectural glass
substrate 825 (load lock 804 has a corresponding exit port).
Substrate 825 is supported by a pallet, 820, which travels along a
track, 815. In this example, pallet 820 is supported by track 815
via hanging but pallet 820 could also be supported atop a track
located near the bottom of apparatus 800 or a track, e.g., mid-way
between top and bottom of apparatus 800. Pallet 820 can translate
(as indicated by the double headed arrow) forward and/or backward
through system 800. For example during lithium deposition, the
substrate may be moved forward and backward in front of a lithium
target, 830, making multiple passes in order to achieve a desired
lithiation. Pallet 820 and substrate 825 are in a substantially
vertical orientation. A substantially vertical orientation is not
limiting, but it may help to prevent defects because particulate
matter that may be generated, e.g., from agglomeration of atoms
from sputtering, will tend to succumb to gravity and therefore not
deposit on substrate 825. Also, because architectural glass
substrates tend to be large, a vertical orientation of the
substrate as it traverses the stations of the integrated deposition
system enables coating of thinner glass substrates since there are
less concerns over sag that occurs with thicker hot glass.
[0164] Target 830, in this case a cylindrical target, is oriented
substantially parallel to and in front of the substrate surface
where deposition is to take place (for convenience, other sputter
means are not depicted here). Substrate 825 can translate past
target 830 during deposition and/or target 830 can move in front of
substrate 825. The movement path of target 830 is not limited to
translation along the path of substrate 825. Target 830 may rotate
along an axis through its length, translate along the path of the
substrate (forward and/or backward), translate along a path
perpendicular to the path of the substrate, move in a circular path
in a plane parallel to substrate 825, etc. Target 830 need not be
cylindrical, it can be planar or any shape necessary for deposition
of the desired layer with the desired properties. Also, there may
be more than one target in each deposition station and/or targets
may move from station to station depending on the desired
process.
[0165] Integrated deposition system 800 also has various vacuum
pumps, gas inlets, pressure sensors and the like that establish and
maintain a controlled ambient environment within the system. These
components are not shown, but rather would be appreciated by one of
ordinary skill in the art. System 800 is controlled, e.g., via a
computer system or other controller, represented in FIG. 8B by an
LCD and keyboard, 835. One of ordinary skill in the art would
appreciate that embodiments herein may employ various processes
involving data stored in or transferred through one or more
computer systems. Embodiments also relate to the apparatus, such
computers and microcontrollers, for performing these operations.
These apparatus and processes may be employed to deposit
electrochromic materials of methods herein and apparatus designed
to implement them. The control apparatus may be specially
constructed for the required purposes, or it may be a
general-purpose computer selectively activated or reconfigured by a
computer program and/or data structure stored in the computer. The
processes presented herein are not inherently related to any
particular computer or other apparatus. In particular, various
general-purpose machines may be used with programs written in
accordance with the teachings herein, or it may be more convenient
to construct a more specialized apparatus to perform and/or control
the required method and processes.
[0166] As mentioned, the various stations of an integrated
deposition system may be modular, but once connected, form a
continuous system where a controlled ambient environment is
established and maintained in order to process substrates at the
various stations within the system. FIG. 8C depicts integrated
deposition system 800a, which is like system 800, but in this
example each of the stations is modular, specifically, an EC layer
station 806a, an optional IC layer station 806b and a CE layer
station 806c. This embodiment also differs from that shown in FIG.
8A in that the deposition system further includes a patterning
station 840 for forming the patterned layer discussed herein. In a
similar embodiment, the IC layer station 806b is omitted. Modular
form is not necessary, but it is convenient, because depending on
the need, an integrated deposition system can be assembled
according to custom needs and emerging process advancements. For
example, lithium deposition stations (not shown) can be inserted at
relevant locations to provide lithium as desired for the various
layers and sublayers.
[0167] In various embodiments, the apparatus may include one or
more stations for forming a bird friendly layer, for example a
patterned layer and/or a haze-inducing layer. Such stations may be
referred to as patterning stations. A patterning station may be
configured to etch a pre-patterned layer to form a patterned layer.
Etching may occur through any of the methods discussed herein
including, but not limited to, laser etching, plasma etching, ion
milling, etc. Appropriate hardware may be provided to accomplish
these processes. In some cases, an x-y stage may be provided in the
patterning station to help move the substrate as etching occurs
(e.g., laser etching). In some embodiments, the patterning station
may include one or more masks that are applied to a substrate to
help form the pattern (either through etching or deposition). A
positioning system may be included to position the mask as desired
on the substrate.
[0168] In a number of embodiments, the patterning station may be
provided as multiple individual (but connected) stations. Many
configurations are possible. In one example, a first patterning
station may be used to deposit a layer of pre-patterned material, a
second patterning station may be used to apply a mask to the
substrate, a third patterning station may be used to selectively
etch the pre-patterned layer to form a patterned layer, and a
fourth patterning station may be used to remove the mask from the
substrate. In another example, a first patterning station may be
used to position a mask on the substrate, a second patterning
station may be used to selectively deposit material on the
substrate, and a third patterning station may be used to remove the
mask from the substrate. The mask application and removal may also
be done in the same chamber as an etching and/or deposition
process, as mentioned above. Integrated depositions systems such as
the ones shown in FIGS. 8A-8C may also have a TCO layer station
(not shown) for depositing the TCO layer on the EC stack. Depending
on the process demands, additional stations can be added to the
integrated deposition system, e.g., stations for heating/annealing
processes, cleaning processes, laser scribes, rotation processes,
depositing capping layers, depositing defect mitigating insulating
layers (DMILs), performing MTC, fabricating bird friendly layers
(e.g., stations for depositing a pre-patterned layer, stations for
defining a pattern on a pre-patterned layer, stations for etching a
pre-patterned layer to form a patterned layer, stations for making
a layer selectively hazy), etc.
[0169] In some embodiments, one or more transparent substrates of
an electrochromic window may include a pattern formed or applied by
a laser. The pattern, examples of which were described in
connection with FIGS. 3B-3H hereinabove, may be readily discerned
by birds of at least a number of species. In some embodiments, the
laser-formed patterns may be configured to be imperceptible or
nearly imperceptible by humans. In other embodiments, the pattern
may be visible to humans, but designed to be decorative in nature,
unobtrusive or otherwise unobjectionable for the intended use of
the window. Advantageously, the pattern may be created using a
laser to induce microcrack formation and/or change a local
refraction index within or on a surface of one or more of the
transparent substrates. By judicious selection of laser operating
parameters, the pattern may be safely formed without regard to
whether or not an electrochromic stack is disposed on the
substrate.
[0170] In some embodiments, a pattern is created using a laser
marking instrument. The pattern may be likewise visible to the
human and avian eye. The pattern may be composed of elements, such
as lines or dots, that appear opaque, semitransparent or
translucent and thus contrast with portions of the transparent
substrate adjacent to the pattern elements. The elements forming
the pattern may be of any shape and size and may be separated by
several centimeters or less. In some implementations, a cross
sectional dimension of the elements may be small enough (e.g.,
0.1-0.5 mm) to be imperceptible or nearly imperceptible by humans,
and yet large enough to be perceptible by birds. Whether or not
perceptible to humans, the pattern may be configured to create a
visual deterrent to birds which recognize the space the window
occupies as a barrier to be avoided.
[0171] In some embodiments, a laser operating regime is selected to
form patterns with the desired opacity and relief without risk of
damage to an electrochromic stack disposed on the substrate. For
example, the laser operating regime may contemplate a train of
micro-pulses, each micro-pulse being a few nanoseconds duration
each, which integrates into a longer duration laser pulse of about
100-1000 microsecond. This regime has been found to diminish
thermal stresses and avoids causing damage to any electrochromic
stack that may be disposed on the substrate. Suitable lasers for
the contemplated pattern formation include, for example, carbon
dioxide (CO.sub.2) lasers having a wavelength of 10600 nm and
nanosecond yttrium-aluminum-garnet (YAG) laser having a wavelength
of 1064 nm or 532 nm.
[0172] In some embodiments, the optical properties of a surface of
a glass substrate may be locally changed. Where the glass substrate
is, or is intended to be, integrated into an IGU, the surface may
face an interior or exterior of the IGU. Moreover, the glass
substrate may be an inboard or outboard lite of the IGU. Where the
glass substrate has an electrochromic layer already disposed
thereon, the glass surface to which the laser is applied may be
opposite to the surface on which the electrochromic stack is
disposed. FIG. 9A illustrates an example of forming a pattern on a
surface of a glass substrate. A laser beam 930 is focused to
impinge a surface 941 of the substrate 940.
[0173] In some embodiments, the optical properties of an interior
portion of a glass substrate may be locally changed. For example,
by appropriately focusing laser radiation within the glass
substrate, optically scattering microcracks may be created. The
microcracks may result from the focused laser radiation causing
local heating of the glass, with a consequent thermal expansion
that creates tensile stresses which in turn produce the
microcracks. FIG. 9B illustrates an example of forming a pattern in
the interior of a glass substrate. Here, the laser beam 930 is
focused inside the glass substrate 940 and the pattern is formed
between the opposite surfaces of the substrate (either or both of
which surfaces may include an electrochromic stack).
[0174] In some embodiments the optical properties of a glass
substrate may be locally changed without necessarily creating
microcracks. For example, a laser-induced local change to the
refraction index may be configured to form a pattern that is
visible to birds but invisible to humans. Suitable lasers for the
contemplated pattern formation include, as indicated hereinabove,
CO.sub.2 lasers having a wavelength of 10600 nm and YAG lasers
having a wavelength of 1064 nm or 532 nm.
[0175] In some embodiments, a pulse fluence of the laser may be
configured to have a value below a microcracking threshold of the
glass, but that is sufficient to create a local densification that
locally increases the refractive index of the glass. For example a
"burst mode" laser operating regime has been considered wherein
each laser pulse consists of a train of 4 to 10 micro-pulses. The
inventors have found that such a train of pulses may produce a
cumulative effect such that the refraction index of the irradiated
zone is increased without creating microcracks. For example, the
refraction index may be increased from a range of 1.5-1.53 (typical
for glass in the spectral range of 350 to 400 nm) to a range of
about 1.55-1.57. The local zones with elevated refraction index
selectively absorb an increased fraction of UV light. As indicated
hereinabove, it is known that many bird species can discriminate in
wavelengths of light in the near-UV range, which wavelengths are
smaller than the threshold wavelengths observable by humans,
typically about 400 nm. Thus, birds may be expected to see the
pattern while humans will not.
[0176] In some embodiments, filament propagation, or
"filamentation" conditions may be exploited in order to increase
the range of depths within which a change in the refraction index
may be produced. Filamentation relates to an optical effect which
facilitates the propagation of a beam of light through a medium
without diffraction.
[0177] In some further embodiments, a diffractive pattern may be
formed on the glass surface, by means of a laser treatment. The
pattern may be configured to diffract incident light under
different angles for different parts of spectrum. As a result, the
pattern will be visible to an approaching bird irrespective of its
angle of trajectory with respect to the window surface. The pattern
may be visible to humans as well as to birds.
[0178] In some embodiments, the pattern may include a number of
micro-spots that are aligned and separated from each other so that
they form a diffraction grating. FIG. 10A illustrates an example of
forming a pattern on a surface of a glass substrate. A laser beam
1030 is focused to impinge a surface 1041 of the substrate 1040. As
may be observed in View AA, the diffraction grating may cause light
incident on the grating at an angle .alpha. to normal to be
diffracted at an angle .beta. to normal.
[0179] The diameters of the micro-spots may be, for example, in an
approximate range between about 1 and about 50 .mu.m, while the
separation between them may be in an approximate range between
about 1 and about 100 .mu.m. By modifying the dimensions of the
micro-spots and the separation between them, the power of
separation of the diffraction grating can be changed. The spots may
be created inside the glass and/or on the surface.
[0180] In one embodiment of the invention, the diffraction grating
is formed on the glass surface by an ablation process. A suitable
laser for the contemplated pattern formation includes a YAG laser
having a wavelength of 355 nm or 266 nm, for example. The laser may
be operated, in a burst mode, each burst including a few
micropulses, each micropulse having a pulse duration in the
nanosecond range. In some embodiments, a burst may include a train
of at least two micropulses. As examples, bursts of 4-5
micropulses, 3-6 micropulses or 2-7 micropulses have been
considered.
[0181] Such a train of pulses has been found to produce a
cumulative effect, where the first pulse increases the refraction
index of the irradiated zone at a layer near the surface from a
range of 1.5-1.53 (typical for glass in the spectral range of 350
to 400 nm) to a range of about 1.55-1.57. As a result, a microlens
may be formed that may further focus the laser beam, and produce an
energy density above a threshold for ablation. In some embodiments,
the most deeply ablated portion may amount to a micro-perforation
having a diameter of only a few microns (e.g., 10) in diameter.
Advantageously, the micoperforation may increase the resolution of
the diffraction grating.
[0182] FIG. 10B shows a plan view of a pattern configured as a
diffraction grating formed in accordance with the above described
techniques while FIG. 10C illustrates a depth profile of the
pattern, created by laser ablation along the line B-B. As can be
seen in the figure, for this specific pattern, the crater diameter
is about 50 .mu.m, while the depth at the center of crater is about
1.4 .mu.m. This means that the crater has a diameter nearly 40
times larger than depth. As a result of this configuration, the
likelihood of trapping environmental contamination is reduced
[0183] Referring now to FIG. 11, a method 1100 for forming a
pattern on a transparent substrate of an electrochromic window is
illustrated. As described hereinabove, at least one of the
substrates of the electrochromic window is an electrochromic (EC)
lite having an EC device disposed thereon. At block 1110, the EC
lite may be prepared by disposing an EC device on a first
transparent substrate. At block 1120, a pattern is formed, with a
laser, the pattern including a first feature configured to provide
a set of optical properties different than that of the transparent
substrates. The pattern may include elements including one or more
intersecting or non-intersecting stripes or bars and/or a plurality
of dots. The set of optical properties may include one or more
characteristics of refractivity, reflectivity and diffraction.
[0184] In some embodiments, forming the pattern on the EC light may
include operating the laser in a regime selected to form the
pattern without damaging the electrochromic device.
[0185] In some embodiments, the laser operating regime includes a
train of micro-pulses, each micro-pulse being less than 10
nanoseconds duration and the train of micro-pulses integrates into
a laser exposure period of about 100-1000 microsecond.
[0186] In some embodiments, forming the pattern on the EC includes
operating the laser in a regime selected to form the pattern
elements by inducing local changes to a refraction index of the EC
light.
[0187] In some embodiments, the pattern may includes a diffraction
grating on a surface of the EC light opposite to the electrochromic
device and forming the diffraction grating on the EC light includes
operating the laser in a regime selected to locally ablate
micro-spots each micro-spot having a dimension in the range of 1 to
50 nm.
[0188] Although the foregoing embodiments have been described in
some detail to facilitate understanding, the described embodiments
are to be considered illustrative and not limiting. It will be
apparent to one of ordinary skill in the art that certain changes
and modifications can be practiced within the scope of the appended
claims.
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