U.S. patent application number 17/309332 was filed with the patent office on 2022-05-05 for adhesive bus bars in electrochromic windows.
This patent application is currently assigned to View, Inc.. The applicant listed for this patent is View, Inc.. Invention is credited to Robin Friedman, Imran Khan, Illayathambi Kunadian, Anshu A. Pradhan, Robert T. Rozbicki, Zoran Topalovic.
Application Number | 20220137472 17/309332 |
Document ID | / |
Family ID | 1000006285052 |
Filed Date | 2022-05-05 |
United States Patent
Application |
20220137472 |
Kind Code |
A9 |
Friedman; Robin ; et
al. |
May 5, 2022 |
ADHESIVE BUS BARS IN ELECTROCHROMIC WINDOWS
Abstract
Embodiments described include adhesive bus bars for
electrochromic or other optical state changing devices. The bus
bars are configured to color match and/or provide minimal optical
contrast with their surrounding environment in the optical device,
provide better adhesion than ink based bus bars, as well as obviate
the need to mitigate defects in underlaying layers.
Inventors: |
Friedman; Robin; (Sunnyvale,
CA) ; Pradhan; Anshu A.; (Collierville, TN) ;
Khan; Imran; (Milpitas, CA) ; Kunadian;
Illayathambi; (San Jose, CA) ; Rozbicki; Robert
T.; (Saratoga, CA) ; Topalovic; Zoran;
(Milpitas, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
View, Inc. |
Milpitas |
CA |
US |
|
|
Assignee: |
View, Inc.
Milpitas
CA
|
Prior
Publication: |
|
Document Identifier |
Publication Date |
|
US 20220019114 A1 |
January 20, 2022 |
|
|
Family ID: |
1000006285052 |
Appl. No.: |
17/309332 |
Filed: |
November 26, 2019 |
PCT Filed: |
November 26, 2019 |
PCT NO: |
PCT/US2019/063453 PCKC 00 |
371 Date: |
May 21, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16453891 |
Jun 26, 2019 |
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17309332 |
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15780606 |
May 31, 2018 |
10884311 |
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16453891 |
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16523852 |
Jul 26, 2019 |
11065845 |
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15780606 |
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15934854 |
Mar 23, 2018 |
10409130 |
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16523852 |
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15364162 |
Nov 29, 2016 |
9995985 |
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15934854 |
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14512297 |
Oct 10, 2014 |
9703167 |
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15364162 |
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13456056 |
Apr 25, 2012 |
9958750 |
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14512297 |
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13431729 |
Mar 27, 2012 |
9102124 |
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13456056 |
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12941882 |
Nov 8, 2010 |
8164818 |
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13431729 |
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13312057 |
Dec 6, 2011 |
8711465 |
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13456056 |
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62771516 |
Nov 26, 2018 |
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61435914 |
Jan 25, 2011 |
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61421154 |
Dec 8, 2010 |
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Current U.S.
Class: |
359/275 |
Current CPC
Class: |
B32B 2262/103 20130101;
B32B 2307/202 20130101; G02F 1/155 20130101; E06B 9/24 20130101;
B32B 7/12 20130101; B32B 17/067 20130101; B32B 5/024 20130101; B32B
2307/732 20130101; E06B 3/67321 20130101; B32B 37/12 20130101; E06B
2009/2464 20130101; B32B 2262/106 20130101; B32B 17/061 20130101;
B32B 2307/402 20130101; G02F 1/133302 20210101; E06B 3/6722
20130101; G02F 1/161 20130101; G02F 2202/28 20130101 |
International
Class: |
G02F 1/155 20060101
G02F001/155; G02F 1/161 20060101 G02F001/161; G02F 1/1333 20060101
G02F001/1333; E06B 9/24 20060101 E06B009/24; E06B 3/67 20060101
E06B003/67; E06B 3/673 20060101 E06B003/673; B32B 7/12 20060101
B32B007/12; B32B 37/12 20060101 B32B037/12; B32B 5/02 20060101
B32B005/02; B32B 17/06 20060101 B32B017/06 |
Claims
1. An electrochromic insulated glass unit comprising: a first
transparent substrate; a second transparent substrate; a spacer
sandwiched between the first and second transparent substrates; an
electrochromic device coating disposed on the first transparent
substrate, the electrochromic device coating comprising a first
transparent conductive layer, a second transparent conductive layer
and an electrochromic device stack disposed between the first and
second transparent conductive layers; and a first adhesive bus bar
on the first transparent conductive layer; wherein the first
adhesive bus bar is between the spacer and the first transparent
substrate at least along 90% of its longest dimension.
2. The electrochromic insulated glass unit of claim 1, wherein the
first adhesive bus bar is between the spacer and the first
transparent substrate entirely along its longest dimension.
3. The electrochromic insulated glass unit of claim 1, wherein the
first adhesive bus bar comprises a first leg comprising (1) a first
portion, between the first transparent substrate and the spacer,
spanning along substantially entire length of a side of the spacer,
and (2) a second portion emanating from between the first
transparent substrate and the spacer and extending to a secondary
seal area on the first transparent substrate.
4. The electrochromic insulated glass unit of claim 1, wherein the
first adhesive bus bar comprises an electrically conductive
adhesive and an electrically conductive backing.
5. The electrochromic insulated glass unit of claim 4, wherein the
electrically conductive backing comprises at least one of a metal,
a metallized plastic, a metallized woven fabric, a carbon fiber, an
alloy, and a metallized carbon fiber.
6. The electrochromic insulated glass unit of claim 4, wherein the
electrically conductive backing comprises a metal foil.
7. The electrochromic insulated glass unit of claim 6, wherein the
metal foil comprises at least one of silver, aluminum, titanium,
tin, zinc, gold, nickel, copper and alloys thereof.
8. The electrochromic insulated glass unit of claim 7, wherein the
metal foil comprises a laminated metal.
9. The electrochromic insulated glass unit of claim 8, wherein the
metal foil comprises tin-plated copper.
10. The electrochromic insulated glass unit of claim 6, where the
metal foil comprises a doped metal.
11. The electrochromic insulated glass unit of claim 10, wherein
the doped metal is silver doped with palladium.
12. The electrochromic insulated glass unit of claim 1, further
comprising a second adhesive bus bar on the second transparent
conductive layer.
13. The electrochromic insulated glass unit of claim 12, wherein
the first and second adhesive bus bars have same composition.
14. The electrochromic insulated glass unit of claim 6, wherein the
metal foil is between about 5 .quadrature.m and about 100
.quadrature.m thick.
15. The electrochromic insulated glass unit of claim 6, wherein the
metal foil is between about 5 .quadrature.m and about 50
.quadrature.m thick.
16. The electrochromic insulated glass unit of claim 6, wherein the
metal foil is between about 5 .quadrature.m and about 40
.quadrature.m thick.
17. The electrochromic insulated glass unit of claim 6, wherein the
metal foil is between about 5 .quadrature.m and about 20
.quadrature.m thick.
18. The electrochromic insulated glass unit of claim 4, wherein the
electrically conductive adhesive comprises an adhesive and a
conductive filler.
19. The electrochromic insulated glass unit of claim 18, wherein
the conductive filler is selected from the group consisting of
silver, gold, nickel, copper, carbon black, carbon fiber, metalized
carbon fiber, carbon nanotubes, fullerenes, graphite, metal-coated
glass beads, metal-coated glass flakes, metal-coated glass fibers,
and meta-coated nickel particles.
20. The electrochromic insulated glass unit of claim 18, wherein
the conductive filler comprises metal-coated particles, wherein a
metal coating on the metal-coated particles is selected from the
group consisting of tin, silver, gold, copper and nickel.
21. The electrochromic insulated glass unit of claim 18, wherein
the conductive filler comprises particles having shapes selected
from the group consisting of spheres, rods, flakes, and irregular
shapes.
22. The electrochromic insulated glass unit of claim 21, wherein
the conductive filler particles comprise a maximum dimension that
does not exceed 25 .mu.m or a minimum dimension that is not less
than about 0.5 .mu.m.
23. The electrochromic insulated glass unit of claim 4, wherein the
first adhesive bus bar comprises same or similar color as the
spacer and/or a primary sealant between the spacer and the first
transparent substrate.
24. The electrochromic insulated glass unit of claim 23, wherein
the electrically conductive backing comprises a color that
approximates the color of the spacer and/or a primary sealant.
25. The electrochromic insulated glass unit of claim 23, wherein
the electrically conductive adhesive comprises a tinting agent so
that the electrically conductive adhesive approximates the color of
the spacer and/or the primary sealant.
26. The electrochromic insulated glass unit of claim 25, wherein
the tinting agent comprises at least one of carbon black, graphite,
carbon nanotubes and fullerenes.
27-160. (canceled)
161. The electrochromic insulated glass unit of claim 1, wherein
the first adhesive bus bar comprises: a first leg between the first
transparent substrate and the spacer, the first leg spanning along
substantially entire length of a first side of the spacer and
extending to a first vertex between the first transparent substrate
and the spacer; a second leg, extending from the first vertex,
between the first transparent substrate and the spacer, extending
along a second side of the spacer and to a second vertex between
the first transparent substrate and the spacer; and a third leg,
extending from the second vertex, and including a first portion
emanating from between the first transparent substrate and the
spacer on the second side and outside the spacer's outer perimeter,
the first portion extending to an area proximate a corner of the
first transparent substrate; and wherein the electrochromic
insulated glass unit further comprises a second adhesive bus bar,
the second adhesive bus bar comprising: (a) a first portion,
between the first transparent substrate and the spacer, spanning
along substantially entire length of a third side of the spacer,
opposite the first side, and (b) a second portion emanating from
between the first transparent substrate and the spacer and
terminating at the area.
162. The electrochromic insulated glass unit of claim 161, wherein
the first transparent substrate and the spacer are rectangular.
163. The electrochromic insulated glass unit of claim 161, wherein
the electrochromic device coating is a monolithic device whose
perimeter edges lie between the spacer and the first transparent
substrate.
164. The electrochromic insulated glass unit of claim 163, wherein
the electrochromic device coating is all solid state and
inorganic.
165. The electrochromic insulated glass unit of claim 161, wherein
each adhesive bus bar of the first and second adhesive bus bars
comprises an electrically conductive adhesive with a metal foil
backing.
166. The electrochromic insulated glass unit of claim 161, wherein
at least one of the first and second vertexes are fabricated by
adhering two adhesive bus bar portion ends with or without pressure
and/or heat.
167. The electrochromic insulated glass unit of claim 166, wherein
the two adhesive bus bar portion ends are soldered together.
168. The electrochromic insulated glass unit of claim 161, wherein
at least one of the first and second vertexes are fabricated by at
least one bending, folding, soldering, welding and brazing.
169. The electrochromic insulated glass unit of claim 161, wherein
the area is between about 1 square inch and about 10 square
inches.
170. The electrochromic insulated glass unit of claim 161, wherein
the area is between about 2 square inches and about 5 square
inches.
171. The electrochromic insulated glass unit of claim 161, wherein
the area is between about 2 square inches and about 3 square
inches.
172. The electrochromic insulated glass unit of claim 1, wherein
the first adhesive bus bar comprises: (1) a first leg between the
first transparent substrate and the spacer, the first leg spanning
along substantially entire length of a first side of the spacer and
extending to a first vertex between the first transparent substrate
and the spacer, and (2) a second leg, extending from the first
vertex, between the first transparent substrate and the spacer, and
along a second side of the spacer, the second leg includes a
portion emanating from between the first transparent substrate and
the spacer on a third side of the spacer opposite the first side
and extending to an area on and proximate a corner of the first
transparent substrate outside the spacer's outer perimeter; and
wherein the electrochromic insulated glass unit further comprises a
second adhesive bus bar, the second adhesive bus bar comprising:
(a) a first arm between the first transparent substrate and the
spacer, the first arm spanning along substantially entire length of
the third side of the spacer and extending to a first corner
between the first transparent substrate and the spacer, and (b) a
second arm, extending from the first corner and includes a portion
emanating from between the first transparent substrate and the
spacer on the third side of the spacer and terminating at the
area.
173. The electrochromic insulated glass unit of claim 172, wherein
the first transparent substrate and the spacer are rectangular.
174. The electrochromic insulated glass unit of claim 172, wherein
the electrochromic device coating is a monolithic device whose
perimeter edges lie between the spacer and the first transparent
substrate.
175. The electrochromic insulated glass unit of claim 174, wherein
the electrochromic device coating is all solid state and
inorganic.
176. The electrochromic insulated glass unit of claim 172, wherein
each of the first and second adhesive bus bars comprises an
electrically conductive adhesive with a metal foil backing.
177. The electrochromic insulated glass unit of claim 172, wherein
each of the first vertex and the first corner are fabricated by
adhering two adhesive bus bar portion ends with or without pressure
and/or heat.
178. The electrochromic insulated glass unit of claim 177, wherein
the two adhesive bus bar portion ends are soldered together.
179. The electrochromic insulated glass unit of claim 172, wherein
the first vertex and the first corner are fabricated by at least
one bending, folding, soldering, welding and brazing.
180. The electrochromic insulated glass unit of claim 172, wherein
the area is between about 1 square inch and about 10 square
inches.
181. The electrochromic insulated glass unit of claim 172, wherein
the area is between about 2 square inches and about 5 square
inches.
182. The electrochromic insulated glass unit of claim 172, wherein
the area is between about 2 square inches and about 3 square
inches.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims benefit of and priority to U.S.
Provisional Patent Application No. 62/771,516, filed on Nov. 26,
2018 and titled "ADHESIVE BUS BARS IN ELECTROCHROMIC GLASS
STRUCTURES;" this application is also a continuation-in-part of
U.S. patent application Ser. No. 15/780,606, filed on May 31, 2018
and titled "OBSCURING BUS BARS IN ELECTROCHROMIC GLASS STRUCTURES,"
which is a national stage application under 35 U.S.C .sctn. 371 to
International Application PCT/US16/67813 (designating the United
States), filed on Dec. 20, 2016 and titled "OBSCURING BUS BARS IN
ELECTROCHROMIC GLASS STRUCTURES," which claims benefit of and
priority to U.S. Provisional Patent Application 62/270,461, titled
"OBSCURING BUS BARS IN ELECTROCHROMIC GLASS STRUCTURES" and filed
on Dec. 21, 2015; International Application PCT/US16/67813 is a
continuation-in-part of U.S. patent application Ser. No. 15/038,727
(now U.S. Pat. No. 9,952,481), titled "OBSCURING BUS BARS IN
ELECTROCHROMIC GLASS STRUCTURES," and filed on May 23, 2016, which
is a national stage application under 35 U.S.C. .sctn. 371 to
International Application PCT/US14/72362 (designating the United
States), filed on Dec. 24, 2014 and titled "OBSCURING BUS BARS IN
ELECTROCHROMIC GLASS STRUCTURES," which claims benefit of and
priority to U.S. Provisional Patent Application No. 61/920,684,
titled "OBSCURING BUS BARS IN ELECTROCHROMIC GLASS STRUCTURES" and
filed on Dec. 24, 2013; this application is also a
continuation-in-part of U.S. patent application Ser. No.
16/453,891, filed on Jun. 26, 2019, titled "MITIGATING DEFECTS IN
AN ELECTROCHROMIC DEVICE UNDER A BUS BAR," which is a continuation
of U.S. patent application Ser. No. 16/249,822, filed on Jan. 16,
2019, titled "MITIGATING DEFECTS IN AN ELECTROCHROMIC DEVICE UNDER
A BUS BAR," which is a continuation of U.S. patent application Ser.
No. 15/537,370, filed on Jun. 16, 2017 and titled "MITIGATING
DEFECTS IN AN ELECTROCHROMIC DEVICE UNDER A BUS BAR," which is a
national stage application under 35 U.S.C .sctn. 371 to
International Application PCT/US15/65910 (designating the United
States), filed on Dec. 15, 2015 and titled "MITIGATING DEFECTS IN
AN ELECTROCHROMIC DEVICE UNDER A BUS BAR," which claims benefit of
and priority to U.S. Provisional Patent Application 62/094,862,
titled "MITIGATING DEFECTS IN AN ELECTROCHROMIC DEVICE UNDER A BUS
BAR" and filed on Dec. 19, 2014; all of these applications are
hereby incorporated by reference in their entireties and for all
purposes.
FIELD
[0002] The embodiments disclosed herein relate generally to
apparatus and techniques for providing bus bars and other features
within an electrochromic (electrochromic) glass structure assembly
having, for example, one or more insulated glass units (insulated
glass units).
BACKGROUND
[0003] 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 is tungsten
oxide. Tungsten oxide is a cathodic electrochromic material in
which a coloration transition, transparent to blue, occurs by
electrochemical reduction.
[0004] Electrochromic materials may be incorporated into, for
example, windows for home, commercial and other uses. The color,
transmittance, absorbance, and/or reflectance of such windows may
be changed by inducing a change in the electrochromic material,
that is, electrochromic windows are windows that can be darkened or
lightened electrically. A small voltage applied to an
electrochromic device of the window will cause them to darken;
reversing the voltage causes them to lighten. This capability
allows control of the amount of light that passes through the
windows and presents an opportunity for electrochromic windows to
be used as energy-saving devices.
[0005] While electrochromism was discovered in the 1960s,
electrochromic devices, and particularly electrochromic windows,
still unfortunately suffer various problems and have not begun to
realize their full commercial potential despite many recent
advances in electrochromic technology, apparatus and related
methods of making and/or using electrochromic devices.
SUMMARY
[0006] Certain aspects pertain to an electrochromic insulated glass
unit comprising a first transparent substrate, a second transparent
substrate, a spacer sandwiched between the first and second
transparent substrates, an electrochromic device coating disposed
on the first transparent substrate, and a first adhesive bus bar on
the first transparent conductive layer. The electrochromic device
coating comprises a first transparent conductive layer, a second
transparent conductive layer, and an electrochromic device stack
disposed between the first and second transparent conductive
layers. The first adhesive bus bar is between the spacer and the
first transparent substrate at least along the longest dimension.
In one aspect, the first adhesive bus bar comprises an electrically
conductive adhesive and an electrically conductive backing
comprising e.g., at least one of a metal, a metallized plastic, a
metallized woven fabric, a carbon fiber, an alloy, and a metallized
carbon fiber. In one aspect, the first adhesive bus bar comprises a
metal foil. In one aspect, the electrically conductive adhesive
comprises an adhesive and a conductive filler. In one aspect, the
adhesive bus bar comprises the same or similar color as the spacer
and/or a primary sealant between the spacer and the first
transparent substrate.
[0007] Certain aspects pertain to a method of fabricating an
electrochromic device. The method comprises (a) applying an
electrically conductive adhesive to a transparent conductive layer
of the electrochromic device, (b) applying an electrically
conductive backing to the electrically conductive adhesive, and (c)
applying a pressure and/or heat to the electrically conductive
backing. The electrically conductive adhesive is sandwiched between
the transparent conductive layer and the electrically conductive
backing. In one aspect, (c) comprises the pressure and the heat to
flow the electrically conductive adhesive and/or initiate
cross-linking of polymer precursors of the electrically conductive
adhesive. In another aspect, the pressure is applied using a press
or a roller. In another aspect, the electrically conductive
adhesive comprises a two-part epoxy. In another aspect, the
electrically conductive adhesive comprises an a-stage adhesive. In
another aspect, the method is performed in the order (a), then (b),
and then (c) or performed in the order (b), then (a), and then (c).
In another aspect, the electrically conductive adhesive comprises a
b-stage adhesive. In another aspect, (c) further comprises applying
an ultraviolet light to the electrically conductive adhesive. In
another aspect, the heat is applied using at least one of an oven,
a heat lamp, a laser, a hot roller and a hot press. In other
aspects, applying the heat comprises heating to: (i) between about
80.degree. C. and about 400.degree. C.; (ii) between about
100.degree. C. and about 350.degree. C.; (iii) between about
150.degree. C. and about 250.degree. C.; (iv) between about
150.degree. C. and about 200.degree. C.; or (v) between about
160.degree. C. and about 180.degree. C. In other aspects, applying
the heat comprises heating for (i) between about 1 minute and about
60 minutes; (ii) between about 5 minutes and about 30 minutes; and
(iii) for between about 10 minutes and 20 minutes; or (iv) between
about 150.degree. C. and about 200.degree. C., for between about 10
minutes and about 20 minutes. In other aspects, applying the
pressure comprises applying pressure at between (i) about 5 psi and
about 100 psi; (ii) about 10 psi and about 50 psi; and (iii) about
10 psi and about 25 psi. In another aspect, (c) comprises applying
a first pressure and the heat to melt the electrically conductive
adhesive, followed by a cure without pressure, at the same or
different temperature as applied during the first pressure
application.
[0008] Certain aspects pertain to an electrochromic insulated glass
unit comprising (a) a transparent substrate comprising an
electrochromic device coating thereon, (b) a spacer sandwiched
between the transparent substrate and another substrate, and (c) a
first bus bar, and (d) a second bus bar. The first bus bar
comprises a first leg and a second leg. The first leg includes a
first portion and a second portion. The first portion of the first
bus bar is between the transparent substrate and the spacer and
spans along substantially the entire length of a first side of the
spacer. The second portion of the first bus bar emanates from
between the transparent substrate and the spacer and extends to a
vertex outside the spacer's outer perimeter at a second side of the
spacer. The second leg extends from the vertex and ends at an area
on and proximate a corner of the transparent substrate. The second
bus bar includes a first portion and second portion. The first
portion of the second bus bar is between the transparent substrate,
spanning along substantially the entire length of a third side,
opposite the first side of the spacer. The second emanates from
between the transparent substrate and the spacer and terminates at
the area. The transparent substrate and the spacer are
rectangular
[0009] Certain aspects pertain to an electrochromic insulated glass
unit comprising (a) a transparent substrate comprising an
electrochromic device coating thereon, (b) a spacer sandwiched
between the transparent substrate and another substrate, and (c) a
first bus bar, and (d) a second bus bar. The first bus bar
comprises a first leg, a second leg, and third leg. The first leg
is between the transparent substrate and the spacer. The first leg
spans along substantially the entire length of a first side of the
spacer and extends to a first vertex between the transparent
substrate and the spacer. The second leg extends from the first
vertex between the transparent substrate and the spacer and extends
along a second side of the spacer to a second vertex between the
transparent substrate and the spacer. The third leg extends from
the second vertex. The third leg includes a first portion emanating
from between the transparent substrate and the spacer on the second
side and outside the spacer's outer perimeter and extends to an
area proximate a corner of the transparent substrate. The second
bus bar includes a first portion that is between the transparent
substrate and the spacer and that spans along substantially the
entire length of a third side of the spacer, opposite the first
side. The second portion of the second bus bar emanates from
between the transparent substrate and the spacer and terminates at
the area. The transparent substrate and the spacer are
rectangular.
[0010] Certain aspects pertain to an electrochromic insulated glass
unit comprising (a) a transparent substrate comprising an
electrochromic device coating thereon, (b) a spacer sandwiched
between the transparent substrate and another substrate, and (c) a
first bus bar, and (d) a second bus bar. The first bus bar
comprises a first leg and a second leg. The first leg is between
the transparent substrate and the spacer and spans along
substantially the entire length of a first side of the spacer and
extends to a first vertex between the transparent substrate and the
spacer. The second leg extends from the first vertex, between the
transparent substrate and the spacer, and along a second side of
the spacer. The second leg includes a portion emanating from
between the transparent substrate and the spacer on a third side of
the spacer opposite the first side and extending to an area on and
proximate a corner of the transparent substrate outside the
spacer's outer perimeter. The second bus bar comprises a first arm
and a second arm. The first arm is between the transparent
substrate and the spacer. The first arm spans along substantially
the entire length of the third side of the spacer and extends to a
first corner between the transparent substrate and the spacer. The
second arm extends from the first corner and includes a portion
that emanates from between the transparent substrate and the spacer
on the third side of the spacer and that terminates at the area.
The transparent substrate and the spacer are rectangular.
[0011] Certain aspects pertain to an electrochromic insulated glass
unit comprising (a) a transparent substrate comprising an
electrochromic device coating thereon, (b) a spacer sandwiched
between the transparent substrate and another substrate, and (c) a
first bus bar and a second bus bar, each comprising a first leg, a
second leg, and a third leg. The first leg is between the
transparent substrate and the spacer. The first leg spans along
substantially the entire length of a first side and a second side
of the spacer, respectively. The first and second sides of the
spacer are opposite and parallel to each other. The first leg
extends to a first vertex between the transparent substrate and the
spacer. The second leg is between the transparent substrate and the
spacer, and extends from the first vertex along a third side of the
spacer, between the first and second sides, and extends to a second
vertex between the transparent substrate and the spacer. The third
leg extends from the second vertex and includes a portion,
emanating from between the transparent substrate and the spacer,
and extending to an area on the transparent substrate outside the
spacer's outer perimeter on the third side of the spacer. The
transparent substrate and the spacer are rectangular.
[0012] Certain aspects pertain to an electrochromic insulated glass
unit comprising (a) a transparent substrate comprising an
electrochromic device coating thereon, (b) a spacer sandwiched
between the transparent substrate and another substrate, and (c) a
first bus bar and a second bus bar, each comprising a first leg and
a second leg. The first leg is between the transparent substrate
and the spacer. The first leg spans along substantially the entire
length of a first side and a second side of the spacer,
respectively. The first and second sides of the spacer are opposite
and parallel to each other. The first leg extends to a vertex
between the transparent substrate and the spacer. The second leg
extends from the vertex between the transparent substrate and the
spacer and along a third side and a fourth side of the spacer,
respectively. The third and fourth sides of the spacer are between
the first and second sides of the spacer and opposite and parallel
to each other. The second leg includes a portion emanating from
between the transparent substrate and the spacer to outside the
spacer's outer perimeter on the third and fourth sides of the
spacer, respectively. The portion extends to a first area and a
second area of the transparent substrate, respectively, on and
proximate a first corner and a second corner, diagonally opposed to
each other. The transparent substrate and the spacer are
rectangular.
[0013] Certain aspects pertain to an electrochromic insulated glass
unit comprising (a) a transparent substrate comprising an
electrochromic device coating thereon, (b) a spacer sandwiched
between the transparent substrate and another substrate, and (c) a
first bus bar and a second bus bar, each comprising a first leg, a
second leg, and a vertex. The first leg spans along substantially
the entire length of a first side and a second side of the spacer,
respectively. The first and second sides of the spacer are opposite
and parallel to each other. The first leg includes a portion
emanating from between the transparent substrate and the spacer to
outside the spacer's outer perimeter on a third side and a fourth
side of the spacer, respectively. The third and fourth sides are
between the first and second sides of the spacer and opposite and
parallel to each other. The portion extends to a first area and a
second area of the transparent substrate, respectively. The first
area is proximate a first corner and the second area is proximate a
second corner diagonally opposed to the first corner. The second
leg is between the transparent substrate and the spacer, and along
the third and fourth sides of the spacer, respectively. The vertex
is between the transparent substrate and the spacer, the vertex
formed by an intersection of the first leg and the second leg. The
transparent substrate and the spacer are rectangular.
[0014] Certain aspects pertain to an electrochromic insulated glass
unit comprising (a) a transparent substrate comprising an
electrochromic device coating thereon, (b) a spacer sandwiched
between the transparent substrate and another substrate, and (c) a
first bus bar and a second bus bar, each comprising a first leg, a
second leg, and a vertex. The first leg is between the transparent
substrate and the spacer. The first leg spans along substantially
the entire length of a first side and a second side of the spacer,
respectively. The first and second sides of the spacer are opposite
and parallel to each other. The second leg including a portion
emanating from between the transparent substrate and the spacer on
the first and second sides of the spacer, respectively. The portion
extends to a first area and a second area, respectively, of the
transparent substrate outside the spacer's outer perimeter. The
vertex is between the transparent substrate and the spacer. The
vertex is formed by intersection of the first leg and the second
leg. The transparent substrate and the spacer are rectangular.
[0015] Certain aspects pertain to an electrochromic insulated glass
unit comprising (a) a transparent substrate comprising an
electrochromic device coating thereon, (b) a spacer sandwiched
between the transparent substrate and another substrate, and (c) a
first bus bar and a second bus bar, each comprising a linear span
between the transparent substrate and the spacer along
substantially the entire length of a first side and a second side
of the spacer, respectively. The first and second sides of the
spacer are opposite and parallel to each other. At least one end of
the linear span emanates from between the transparent substrate and
the spacer and extends to a first area and a second area,
respectively, on the transparent substrate outside the spacer's
outer perimeter. The transparent substrate and the spacer are
rectangular.
[0016] Certain aspects pertain to an adhesive bus bar comprising:
(a) an electrically conductive adhesive; and an electrically
conductive backing comprising at least one of a metal, a metallized
plastic, a metallized woven fabric, a carbon fiber, an alloy, and a
metallized carbon fiber.
[0017] Certain aspects pertain to an electrochromic insulated glass
unit comprising (a) a transparent substrate comprising an
electrochromic device coating thereon, (b) a spacer sandwiched
between the transparent substrate and another substrate, and (c) a
first bus bar and a second bus bar, each comprising a first leg, a
second leg, and a third leg. The first leg is between the
transparent substrate and the spacer. The first leg spans along
substantially the entire length of a first side and a second side
of the spacer, respectively. The first and second sides of the
spacer are opposite and parallel to each other. The first leg
extends to a first vertex between the transparent substrate and the
spacer. The second leg is between the transparent substrate and the
spacer, and extends from the first vertex and along a third side
and a fourth side of the spacer, respectively. The third and fourth
sides of the spacer are between the first and second sides of the
spacer and are opposite and parallel to each other. The third leg
emanates from between the transparent substrate and spacer, on the
first and second sides of the spacer, respectively, and extends to
a first and a second area, respectively, on the transparent
substrate outside the spacer's outer perimeter. A second vertex
between the transparent substrate and the spacer is formed by an
intersection of the third leg with the first leg and the second
leg, respectively. The third leg is configured such that there is
approximately equal length of bus bar on either side of the second
vertex. The transparent substrate and the spacer are
rectangular.
[0018] These and other features and embodiments will be described
in more detail below with reference to the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1A is a schematic drawing of a cross section of an
insulated glass unit (insulated glass unit) of an electrochromic
window assembly.
[0020] FIG. 1B is a schematic drawing of plan views of the
insulated glass unit in an un-tinted state and a tinted state.
[0021] FIG. 2A depicts an electrochromic insulated glass unit
configuration.
[0022] FIG. 2B depicts an electrochromic insulated glass unit
configuration.
[0023] FIG. 3 is a schematic illustration of an electrochromic
window assembly depicting a butt joint.
[0024] FIG. 4 is a drawing of a cross-sectional view of adhesive
bus bars disposed on transparent conductive layers of an
electrochromic device.
[0025] FIG. 5 is a drawing of a cross-sectional view of an adhesive
bus bar.
[0026] FIG. 6 is a drawing of a cross-sectional view of an adhesive
bus bar on a transparent conductive layer.
[0027] FIG. 7A is a drawing of a cross-sectional view of an
adhesive bus bar configuration in an insulated glass unit.
[0028] FIG. 7B is a drawing of a cross-sectional view of an
adhesive bus bar configuration in an insulated glass unit.
[0029] FIG. 7C is a drawing of a cross-sectional view of an
adhesive bus bar configuration in an insulated glass unit.
[0030] FIG. 8 depicts a plan view of an adhesive bus bar
configuration.
[0031] FIG. 9 depicts a plan view of an adhesive bus bar
configuration.
[0032] FIG. 10 depicts a plan view of an adhesive bus bar
configuration.
[0033] FIG. 11 depicts a plan view of an adhesive bus bar
configuration.
[0034] FIG. 12 depicts a plan view of an adhesive bus bar
configuration.
[0035] FIG. 13 depicts a plan view of an adhesive bus bar
configuration.
[0036] FIG. 14 depicts a plan view of an adhesive bus bar
configuration.
[0037] FIG. 15 depicts a plan view of an adhesive bus bar
configuration.
[0038] FIG. 16 depicts a plan view of an adhesive bus bar
configuration.
[0039] FIG. 17 depicts a plan view of an adhesive bus bar
configuration.
[0040] FIG. 18 depicts a plan view of an adhesive bus bar
configuration.
[0041] FIG. 19 depicts a plan view of an adhesive bus bar
configuration.
[0042] FIG. 20A depicts aspects of vertices of adhesive bus
bars.
[0043] FIG. 20B depicts aspects of vertices of adhesive bus
bars.
[0044] FIG. 20C depicts aspects of vertices of adhesive bus
bars.
[0045] FIG. 21 depicts a plan view of an adhesive bus bar
configuration.
DETAILED DESCRIPTION
[0046] In the following description, numerous specific details are
set forth in order to provide a thorough understanding of the
presented embodiments. The disclosed embodiments may be practiced
without some or all of these specific details. In other instances,
well-known process operations have not been described in detail to
not unnecessarily obscure the disclosed embodiments. While the
disclosed embodiments will be described in conjunction with the
specific embodiments, it will be understood that it is not intended
to limit the disclosed embodiments. Reference numbers in the
figures may be reused across various figures to denote the same or
analogous structures. For example, an adhesive bus bar is denoted
"370" in various figures, and any instance of "370" is meant to
include adhesive bus bars as described herein and any particular
adhesive bus bar described herein. Thus, if a figure has two such
reference numbers "370" embodiments include where each of the
referenced adhesive bus bars are the same or different adhesive bus
bars.
[0047] An "electrochromic window" can refer to a window including
one or more electrochromic panes (also referred to herein as
electrochromic lites) such as, for example, an insulated glass unit
(IGU) having one or more electrochromic panes or an electrochromic
pane laminated to another pane (an "electrochromic laminate"), the
other pane being electrochromic or not. An "electrochromic window
assembly" is an assembly comprising one or more electrochromic
windows. Each pane or lite of an electrochromic insulated glass
unit may be alone or laminated to another pane, electrochromic or
not. An electrochromic pane (or lite) comprises a substantially
transparent substrate (for example, glass substrate) and an
electrochromic device fabricated on the substrate. Methods of
fabricating electrochromic panes, laminates and insulated glass
units can be found in U.S. patent application Ser. No. 13/456,056
titled "ELECTROCHROMIC WINDOW FABRICATION METHODS," filed on Apr.
25, 2012, which is hereby incorporated by reference in its
entirety. In these fabrication methods, electrochromic panes with
electrochromic devices are fabricated, and then insulated glass
units are manufactured using one or more of the electrochromic
panes. Typically, an insulated glass unit is formed by placing a
spacer, for example made of polymer or metal, for example PVB
(polyvinyl butyral), silicone, aluminum, stainless steel or other
suitable material), between two glass panes, and sealed with an
appropriate adhesive, such as polyisobutylene (PIB) to make a
hermetic seal. After the panes are sealed to the spacer, a
secondary seal is provided around the outer perimeter of the
spacer, for example a polymeric material, for example a
silicone-based material that adds structural support to the
assembly (sometimes referred to as "structural silicone"). In some
cases, a desiccant may be included in the insulated glass unit
frame or spacer during assembly to absorb any moisture. Typically,
but not necessarily, the insulated glass unit is filled with inert
gas such as argon. The completed insulated glass unit can be
installed in, for example, a frame or wall and connected to a power
source (or wirelessly powered) and a controller to control power to
transition the optical states of the electrochromic device(s).
Examples of bus bars and spacers can be found in U.S. patent
application Ser. No. 13/312,057 titled "SPACERS FOR INSULATED GLASS
UNITS" and filed on Dec. 6, 2011 and U.S. patent application Ser.
No. 13/452,032 titled "ANGLED BUS BAR" and filed on Apr. 20, 2012,
which are hereby incorporated by reference in their entirety.
[0048] In a conventional electrochromic glass window, especially on
larger size substrates, manufacturers use a bus bar and/or scribe
lines in the viewable area of the insulated glass unit, for example
due to engineering or a perceived need to do so. The viewable area
or "vision area" is the area of the window that light passes
through. For an insulated glass unit, not installed in a frame, the
viewable area is the area within the inner perimeter of the spacer.
Once an insulated glass unit is installed in a framing system, the
viewable area is defined by the inner perimeter of the window
frame. Bus bars and scribe lines are aesthetically unpleasing due
to the contrast between the electrochromic device and the scribe
line and/or bus bar in the viewable area. Certain manufacturers use
obscuration materials, for example paint or frit, to hide these
features from view, which further reduces the viewable area of the
window.
[0049] FIG. 1A is a schematic drawing of a cross section of an
electrochromic window in the form of an insulated glass unit, 100.
In FIG. 1A, a spacer, 105, is used to separate a first
electrochromic pane 110 from a second pane 220. The first
electrochromic pane includes an electrochromic device fabricated on
a substantially transparent substrate such as a glass substrate.
The second pane 220 in this example is a non-electrochromic pane.
In other examples, second pane 220 can have an electrochromic
device thereon and/or one or more coatings such as low-E coatings
and the like. Between spacer 105 and, in this example, the
substrate of first electrochromic pane 110 is a primary seal, 130.
This primary seal 130 is also between spacer 105 and the second
non-electrochromic pane 220. Around the perimeter of spacer 105 is
a secondary seal, 140 (bus bar wiring may traverse the primary seal
for connection to controller). These seals aid in keeping moisture
out of the interior space, 150, of insulated glass unit 100.
[0050] An observer viewing the insulated glass unit 100 (as
depicted with the stylized eye) will see both bus bars and other
features when the electrochromic coating is darkened or in the
clear state. This is described in more detail below.
[0051] In FIG. 1A, areas 112(a) and 112 (b) represent where the
electrochromic device stack has been removed (for example, by laser
scribing), in this example, at a perimeter region. In this example,
the area 112(a) passes through the second transparent conductive
layer (TCL), the electrochromic stack and the first TCL, and may be
able to isolate the operable electrochromic device from other
portions of the electrochromic device that were potentially damaged
during edge deletion. In certain cases, the electrochromic stack
comprises an electrochromic layer, a counter electrode (CE) layer,
and an optional discrete ion conducting (IC) layer. Area 112(b)
also passes through the second TCL and the device stack, but not
the bottom first TCL, as this serves as the lower conductor in
electrical communication with bus bar 2. Regardless, areas 112(a)
and 112 (b) allow light to pass through the glass, even though the
electrochromic device layers may be darkened. In this example, the
electrochromic stack, the first TCL and the diffusion barrier were
removed in the edge deletion areas, and the outer perimeter of the
electrochromic device does not pass under the spacer into the
primary seal, thus areas 112(c) will also allow light to pass
through even when the electrochromic device is darkened, because
they have no electrochromic coating.
[0052] In FIG. 1A, bus bar 1 160(a) is fabricated on the second TCL
of the electrochromic stack and bus bar 2 160(b) is fabricated on
the first TCL. The illustrated eye shows the perspective of an
observer viewing the insulated glass unit 100 from the outside.
FIG. 1B shows plan views of insulated glass unit 100 in an
un-tinted state (left hand side illustration) and a tinted state
(right hand side illustration) from the perspective of the observer
shown by the illustrated eye in FIG. 1A. As depicted, unless the
techniques for obscuring of certain embodiments are used, the bus
bars and/or the scribe lines in insulated glass unit 100 are
visible in contrast with its background of the electrochromic
device (tinted and untinted). In the tinted state, the scribe lines
are visible against the first electrochromic pane 110 in the tinted
state. Although not shown, the bus bar bus bar 1 160(a) and bus bar
2 160(b) may also be partially visible in the tinted state. In the
untinted state, bus bar bus bar 1 160(a) and bus bar 2 160(b) are
visible. The issues related to visibility of bus bars and scribe
lines in relation to conventional insulated glass units are
addressed by, for example, not putting scribe lines in the viewable
area, or otherwise obscuring them. Similarly, bus bars in the
viewable area may be obscured by using transparent conductive
materials for the bus bars. These concepts are described in U.S.
patent application Ser. No. 15/780,606, filed on May 31, 2018 and
titled "OBSCURING BUS BARS IN ELECTROCHROMIC GLASS STRUCTURES" and
U.S. patent application Ser. No. 15/038,727 (now U.S. Pat. No.
9,952,481), titled "OBSCURING BUS BARS IN ELECTROCHROMIC GLASS
STRUCTURES," and filed on May 23, 2016; both of which are
incorporated by reference herein.
[0053] Improved insulated glass units, for example, as described in
U.S. Pat. No. 9,958,750, which is hereby incorporated by reference
in its entirety, are configured with bus bars under the spacer,
i.e. in the primary seal, of the insulated glass unit. This is
illustrated in FIG. 2A. In FIG. 2A, a partial cross-section of an
electrochromic insulated glass unit 200, bus bar 270 is embedded in
the primary seal 230 of the insulated glass unit 200; that is, the
bus bar is sandwiched between the glass substrate and the spacer
220. Though there should be insulating primary sealant 230 between
the bus bar and the spacer, in order to avoid electrical shorting
between the bus bar and spacer, an electrically insulated spacer,
for example polymeric (for example foam) or metal coated with an
insulating material (for example color matched to the sealant, for
example gray or black insulating material), is used. In the
illustrated example, bus bar 270 is lying on the electrochromic
device 210 disposed on a substrate. Thus when such insulated glass
units are installed in a frame, there are no bus bars visible to
the end user, because they are not in the viewable area, see FIG.
2B; i.e. the frame blocks a line of sight to the bus bars. Still,
if such insulated glass units are glazed using a butt joint without
flashing or other material covering the periphery of the insulated
glass unit as a frame would otherwise do, an observer viewing the
assembly from the outside will see bus bar 270 or other uncoated
regions within the assembly through the glass as in the primary
seal 230 or secondary seal 260, since the intervening
electrochromic coating is transparent. Since bus bars are typically
fabricated from a metallic material such as silver ink, they
usually have a metallic color such as silver. These
metallic-colored bus bars can be visible when seen in contrast with
the rest of the assembly. Typical primary sealants are gray or
black, so the metallic color has a high contrast against this dark
or dull background. It is undesirable from an aesthetic standpoint
to be able to see these bus bars and other uncoated regions (for
example, scribe lines) within the assembly.
[0054] For example, an observer viewing a butt joint between
adjacent insulated glass units of an electrochromic window assembly
might be able to view conventional metallic bus bars within the
assembly. FIG. 3 is a schematic drawing of an electrochromic window
assembly 300 having a butt joint between two (2) insulated glass
units 200 butted together. The dotted oval indicates a top view
cross-section of the butt joint detail. Butt joints are used in
window assemblies to increase the visible area by combining
electrochromic glass windows (for example, insulated glass units)
with little or no extra framing added. Electrochromic window
assemblies that have a butt joint generally have one or more
structural member between the electrochromic glass windows butted
together that provide support at the joint. In the case of butted
insulated glass units, for example, a structural member 302 may
provide support between the panes of the butted insulated glass
units, at least partially in the secondary seal area of each
insulated glass unit. A secondary sealant, 304, such as structural
silicone, covers structural member 302 and provides some rigidity.
In such configurations, the bus bars, 370, but for embodiments
described herein would be visible from the outside looking in
(because the electrochromic pane is typically mounted on the outer
pane of an insulated glass unit). If the adhesive bus bar 370 is
configured to blend in with its background, in this example primary
sealant 230, then the aforementioned aesthetically offending high
contrast is overcome.
[0055] The inventors have discovered that adhesive bus bars with
particular materials and properties are useful to blend in with
their background, for example primary sealants, spacers and
coatings on spacers. Some embodiments relate to methods of applying
adhesive bus bars and also configurations for electrochromic
windows comprising adhesive bus bars described herein.
I. Camouflaging Techniques
[0056] In certain embodiments, camouflaging techniques may be used
to make the bus bar in an electrochromic window the same or similar
color as the "background." "Background" can refer to the element or
elements of the electrochromic window that are visible from outside
of the window from the viewpoint of the observer. In many cases,
the "background" to a bus bar is the spacer or sealant in a primary
seal of an insulated glass unit.
[0057] Contrast can refer to the difference in color (hue) and/or
brightness (luminance) between the foreground feature being
camouflaged and its background. One metric of the differences in
brightness is a luminance contrast ratio between the measured
luminance of the background and measured luminance of the feature
being camouflaged. Examples of different luminance contrast ratios
that can be used include Weber contrast
(C.sub.w=(L.sub.f-L.sub.b)/L.sub.b), Michelson contrast
(C.sub.mich=(L.sub.max-L.sub.min)/(L.sub.max+L.sub.min), Luminance
ratio (CR=L.sub.f/L.sub.b), and RMS contrast, where L.sub.f is the
measured luminance of the feature and L.sub.b is the measured
luminance of the background. One metric of a difference in color
contrast is the Delta E (or .DELTA.E) developed by the
International Commission on Illumination (CIE). Other measurements
of color contrast may also be used such as CIE76, CIE94, CIEDE2000,
etc.
[0058] In one embodiment, the adhesive bus bar backing comprises a
color that approximates the color of the spacer and/or the primary
sealant. In certain embodiments, a tinting agent can be added to
the ECA used to fabricate the bus bar to mask its color and
brightness and camouflage it with its background. Since black is a
common background color, carbon black, or graphite may be used as a
tinting agent in some cases; thus the tinting agent also is an
electrical conductor. Focusing the tinting agent function, in
certain cases, the tinting agent and/or the amount of tinting agent
is selected based on measured luminance contrast ratio and measured
color contrast (for example, measured Delta E) between the final
color of the bus bar and the background. In one case, the tinting
agent and/or amount of tinting agent is selected to be within a
range of acceptable contrast values. In certain embodiments, the
adhesive on a foil bus bar (collectively an "adhesive bus bar")
comprises a carbon material, for example carbon black, carbon
nanotubes, fullerenes, graphite and the like, and thus the adhesive
approximates the color of its background, for example the primary
sealant and/or spacer, coated or not. Certain embodiments include
methods of color matching bus bar adhesive with the bus bar's
background.
[0059] In some embodiments, bus bars may be fabricated from
non-conventional bus bar materials that have the same color or
similar color to the background and are also electrically
conductive such as, for example, certain carbon-based materials.
Some examples of suitable carbon-based materials include materials
having carbon black, graphite, graphite-based materials, graphene,
graphene-based materials, carbon nanotubes, fullerenes, etc. These
materials have been shown to have excellent electrical conductivity
and may be processed to fabricate conductive strips or similar
structures suitable for bus bars.
[0060] In certain aspects, adhesive bus bars of electrochromic
windows described herein reside almost entirely under the spacer or
at least along their longest dimension. In these cases, the bus bar
does not pass beyond the inner perimeter of the spacer, or an edge
bead of primary sealant formed when the spacer and glass are
pressed together to form the primary seal. For example, refer to
FIG. 3. This configuration avoids creating a leak path in the seal
that could potentially allow moisture into the sealed volume of the
insulated glass and/or let gas in the unit to leak out. Since these
bus bars reside under the spacer (sometimes referred to as "in the
primary seal"), the spacer itself blocks the bus bars from being
viewed from one side. In this case, only a single direction of view
of the bus bars from the other side must be obscured by the frame
or camouflaged. In this direction, the bus bars have the primary
seal of the spacer in the background. Since only the view outside
of the inner perimeter of the spacer needs to be blocked from view,
much of the area within the inner perimeter of the spacer is
available as viewable area.
[0061] Examples of bus bars residing under spacers can be found in
U.S. Pat. No. 9,158,173 titled "SPACERS FOR INSULATED GLASS UNITS,"
and filed on Jan. 10, 2014, which is hereby incorporated by
reference in its entirety. FIG. 7A shows an example in larger
detail of a cross section, 700, of an edge region of an insulated
glass unit where the spacer 720 of the insulated glass unit and an
adhesive bus bar 370 reside. In the illustration, the bus bar 370
resides under spacer 720. In this context, "under" is used for
convenience, bus bar 370 is between spacer 720 and one of the glass
substrates of the insulated glass unit. As illustrated, spacer,
720, is sandwiched between two sheets of glass near the edge of the
insulated glass unit. In a typical design, the glass interfaces
directly with a primary seal material, 730, (for example, a thin
elastomeric layer, such as PIB or PVB), which is in direct contact
with spacer 720. In some embodiments, spacer 720 may be metal
spacer, such as a steel spacer, aluminum or a stainless steel
spacer, for example. Spacer 720 may be a foam or polymeric spacer,
such as a silicone foam impregnated with desiccant, which is sealed
with a primary sealant as a metal spacer would be. This three-part
interface (i.e., glass/primary seal material/spacer) exists on both
a top piece of glass and a bottom piece of glass. Spacer 720 may
have a hollow structure, as depicted in FIG. 7A.
[0062] In some embodiments, the spacer may have a substantially
rectangular cross section. In some embodiments the spacer and
primary seal are a single structure, for example Kodispace 4SG is a
reactive thermoplastic material that is extruded and used both as a
spacer and a primary sealing element, commercially available from
H. B. Fuller, of St. Paul Minn., U.S.A. One embodiment is an
electrochromic insulated glass unit as described herein comprising
a thermoplastic spacer. One embodiment is an electrochromic
insulated glass unit as described herein comprising a 4SG spacer.
Without wishing to be bound by theory, it is believed that
placement of an adhesive busbar as described herein under a
thermoplastic spacer, for example a 4SG spacer, provides mechanical
rigidity for sustaining physical contact of the electrically
conductive adhesive to the transparent conductive layer(s) and thus
maintains low contact resistance during operation of the
electrochromic device. During fabrication of the electrochromic
insulated glass unit, the extrusion is at elevated temperature and
thus the thermoplastic conforms around the adhesive busbar creating
an overlapping bond. In one embodiment, thermoplastic spacer is
applied, for example extruded, onto a transparent substrate
comprising an adhesive bus bar on a transparent conductive layer,
for example the adhesive bus bar configured on the transparent
substrate as described herein, to form a spacer. In one embodiment,
the extrusion temperature is between about 115.degree. C. to about
150.degree. C., in one embodiment between about 120.degree. C. to
about 140.degree. C., in one embodiment between about 125.degree.
C. to about 135.degree. C., in one embodiment between about
125.degree. C. to about 130.degree. C., in one embodiment about
128.degree. C. The hot thermoplastic is pressed between the
transparent substrate comprising the electrochromic device with
adhesive bus bar(s) and a second transparent substrate. In one
embodiment, the pressure applied is characterized by deformation
from initial contact/sealing between each of the transparent
substrates and the thermoplastic extrusion in the form of a spacer.
The electrochromic insulated glass unit is formed by pressure on
the transparent substrates toward each other. In one embodiment,
the transparent substrates are compressed from an initial distance
between them to a new distance that is between about 0.2 mm to
about 5 mm shorter than the initial distance, in another embodiment
between about 0.3 mm to about 4 mm shorter than the initial
distance, in another embodiment between about 0.5 mm to about 3 mm
shorter than the initial distance, in another embodiment between
about 1 mm to about 2 mm shorter than the initial distance. In one
embodiment, the thermoplastic spacer is between about 3 mm and
about 10 mm in width (in this context, "width" of a spacer refers
to the dimension of the spacer body orthogonal to the substrate
edge and in the plane of the substrate, in the window industry this
is sometimes referred to as "height"). In one embodiment, the
thermoplastic spacer is between about 5 mm and about 10 mm in
width, in one embodiment, the thermoplastic spacer is between about
7 mm and about 10 mm in width. In one embodiment, the
electrochromic insulated glass unit further comprises a structural
silicone secondary seal.
[0063] At a minimum, spacers described herein have at least two
surfaces, each substantially parallel to the lites of the insulated
glass unit in which they are to be incorporated. The remaining
cross section, for example, surfaces of the spacer that face the
interior space of the insulated glass unit and the exterior,
secondary seal area, space may have any number of contours, i.e.,
they need not be flat, but may be. In some embodiments, the top and
bottom outer corners of the spacer are beveled and/or rounded to
produce a shallower angle in these areas. Rounding, beveling, or
smoothing may be included to ensure there are no sharp edges that
might enhance electrical shorting. An example is depicted in FIG.
7B. Bus bar, 720, is located on electrochromic device stack 710 in
order to make electrical contact with one of the electrodes of the
device. In this example, bus bar 720 is between spacer 720 and the
lower glass lite. Due to the cantilever shape of spacer 720 in this
example, there is more room for sealant 730 and for bus bar 370.
The cantilever shape essentially forms a channel for the bus bar
and primary sealant, between the glass and the cantilevered
overhang portion of the spacer.
[0064] Such spacers for example as shown in FIG. 7B, accommodate
added vertical thickness of adhesive bus bars 370, as well as
wiring that may be needed to deliver power to the bus bar. This
additional volume for bus bar and sealant is provided on both
sealing faces of the spacer, in some embodiments, such a spacer is
used for an insulated glass unit containing two electrochromic
panes. When using a spacer with two such channels in an insulated
glass unit containing one electrochromic lite, there is no need for
special placement of a single channel toward the electrochromic
lite.
[0065] FIG. 7C shows an example of a cross-sectional illustration
of a spacer which has a notch on the bottom to accommodate an
adhesive bus bar. As shown in FIG. 7C, a spacer, 720 has a channel,
780, that accommodates the length of bus bar 370. As in FIG. 7C,
this channel provides more vertical space for adhesive bus bar 370
and sealant 730. Such space may be desirable, for example in
embodiments where a thicker adhesive bus bar is used, for example a
foil backing and/or conductive adhesive may be thicker than in
other embodiments and require more room. Channel 780 in spacer 720
resides in the middle of the underside of spacer 720. The
dimensions of channel 780 are suitable to accommodate bus bar 780.
In some embodiments, the channel width is about 2 millimeters to
about 5 millimeters, and the channel height is about 0.1
millimeters to 1 millimeter. In some embodiments, the channel width
is about 3 millimeters to 4 millimeters, and the channel height is
about 0.1 millimeter to about 0.5 millimeters.
[0066] In some embodiments, the bus bar includes a channel
(sometimes referred to as a "mouse hole") at some angle to the
length of the bus bar, for example orthogonal, for a bus bar lead
(a wire or other conductor that establishes electrical
communication between the bus bar and a power source). A mouse hole
need only penetrate part way under the spacer because the bus bar
resides underneath the spacer, and thus the lead to need not
traverse the entire width of the spacer to reach the bus bar and
make electrical connection. In some embodiments, the bus bar lead
channel resides on an outside edge of the spacer or on an outside
edge of a corner of the spacer.
[0067] In some embodiments, the electrochromic device stack 710
when in a colored state may color all the way under the spacer such
that electrochromic device stack 710 is substantially uniformly
colored in the entire viewable area. Further, the bus bar is not
visible from one side of the insulated glass unit, by virtue of
being under (behind) the spacer, and substantially not visually
discernable from the opposite side of the insulated glass unit by
virtue of the ECA's color substantially matching the primary
sealant and/or the spacer.
[0068] Certain electrochromic insulated glass units or
electrochromic IGUs, that include a first transparent substrate, a
second transparent substrate, a spacer sandwiched between the first
and second substrate, and an electrochromic device coating on the
first transparent substrate. The electrochromic device coating
includes a first transparent conductive layer, a second transparent
conductive layer, and an electrochromic device stack disposed
between the first and second transparent conductive layers. These
electrochromic IGUs also include a first adhesive bus bar disposed
on the first transparent conductive layer where the first adhesive
bus bar is between the spacer and the first transparent substrate
and lies at least along 90% of the longest dimension. For example,
the first adhesive bus bar may lie along at least the side of a
rectangular substrate having the longest dimension. In one
embodiment, the first adhesive bus bar can be between the spacer
and a transparent substrate entirely along its longest dimension,
or, may have a portion that emanates from between the substrate and
the spacer. For example, in one embodiment the first adhesive bus
bar comprises a first leg including a first portion, between the
transparent substrate and the spacer, spanning along substantially
the entire length of a side of the spacer, and including a second
portion emanating from between the transparent substrate and the
spacer and extending to a secondary seal area on the transparent
substrate.
[0069] The first adhesive bus bar may include an electrically
conductive adhesive (ECA) and an electrically conductive backing.
In one embodiment, an electrochromic IGU also includes a second
adhesive bus bar disposed on the second transparent conductive
layer. The first and second adhesive bus bars may have the same
composition. In one embodiment, the first adhesive bus bars bar has
the same or similar color as the spacer and/or a primary sealant
between the spacer and the first transparent substrate. For
example, the electrically conductive backing may have a color that
approximates the color of the spacer and/or a primary sealant. As
another example, the electrically conductive adhesive may have a
tinting agent so that the electrically conductive adhesive
approximates the color of the spacer and/or the primary sealant. In
one aspect, the tinting agent includes at least one of carbon
black, graphite, carbon nanotubes and fullerenes.
[0070] The adhesive bus bar electrically conductive backing can
comprise any metal described herein, metallized plastics,
conductive scrim (metallized woven fabric), carbon fiber,
metallized carbon fiber and the like. In one aspect, the
electrically conductive backing includes at least one of a metal, a
metallized plastic, a metallized woven fabric, a carbon fiber, an
alloy, and a metallized carbon fiber. In another aspect, the
electrically conductive backing is a metal foil, e.g., a metal foil
including at least one of silver, aluminum, titanium, tin, zinc,
gold, nickel, copper, and any alloys thereof. The metal foil may be
a laminated metal, for example, a metal foil including tin-plated
copper. Alternatively, the metal foil may be a doped metal, for
example, silver doped with palladium. Without wishing to be bound
by theory, it is believed that doping silver with palladium
inhibits electromigration of silver. In one embodiment, the metal
foil backing is between about 5 .mu.m and about 100 .mu.m thick, in
another embodiment between about 5 .mu.m and about 50 .mu.m thick,
in another embodiment between about 5 .mu.m and about 40 .mu.m
thick, in another embodiment between about 5 .mu.m and about 20
.mu.m thick. Thinner metal foil can be advantageous as it is
flexible, though thicker foils can have higher electrical
conductivities. A more flexible backing can be desirable because of
its ability to easily conform to contours. In yet another aspect,
the electrically conductive backing includes an adhesive and a
conductive filler. In one embodiment, the conductive filler is
selected from the group consisting of silver, gold, nickel, copper,
carbon black, carbon fiber, metalized carbon fiber, carbon
nanotubes, fullerenes, graphite, metal-coated glass beads,
metal-coated glass flakes, metal-coated glass fibers, and
meta-coated nickel particles. In another embodiment, the conductive
filler includes metal-coated particles, where a metal coating on
the metal-coated particles is selected from the group consisting of
tin, silver, gold, copper and nickel. In another embodiment, the
conductive filler comprises particles having shapes selected from
the group consisting of spheres, rods, flakes, and irregular
shapes. In another embodiment, the conductive filler particles
comprise a maximum dimension that does not exceed 25 .mu.m or a
minimum dimension that is not less than about 0.5 .mu.m.
II. Adhesive Bus Bars
[0071] The inventors have found that when conductive silver ink
based bus bars are applied, the silver may penetrate or migrate
into any defects to cause them to become optically visible via
electrical shorting. This problem, as well as examples of methods
to mitigate the effects of such visible defects, can be found in
U.S. patent application Ser. No. 15/537,370, titled "MITIGATING
DEFECTS IN AN ELECTROCHROMIC DEVICE UNDER A BUS BAR," and filed on
Dec. 15, 2015, which is hereby incorporated by reference in its
entirety. Embodiments herein disclose implementations of methods
and devices that avoid the aforementioned silver problem and may
camouflage bus bars from view as described herein.
[0072] An "adhesive bus bar" refers to a bus bar with an
electrically conductive backing and a conductive adhesive used to
both adhere the bus bar to a transparent conductive layer of an
electrochromic device and also establish electrical communication
between the electrically conductive backing and the transparent
conductive layer. An electrically conductive adhesive ("ECA") may
be, for example an adhesive that is otherwise non-electrically
conductive but includes electrically conductive particles. An ECA
may also be entirely adhesive that is electrically conductive, for
example an organic polymer matrix that has charge-carrying groups,
for example ionic head groups, quaternary amine salts, carboxylic
acid salts, phosphate salts, mixtures thereof, and the like. In one
embodiment, an ECA that entirely adhesive comprises a polymeric
adhesive with charge-carrying agents that are not part of the
polymer chain, such as metal ions, quaternary amine salts,
carboxylic acid salts, phosphate salts, mixtures thereof and the
like. A typical, but non-limiting example of an adhesive bus bar is
a metal foil backing with an electrically conductive adhesive on at
least one side of the metal foil backing.
[0073] The adhesive bus bar electrically conductive backing can
comprise any metal described herein, metallized plastics,
conductive scrim (metallized woven fabric), carbon fiber,
metallized carbon fiber and the like. In one embodiment, the
adhesive bus bar backing is a metal foil. In one embodiment, the
metal foil comprises at least one of silver, aluminum, titanium,
tin, zinc, gold, nickel, copper and alloys thereof. The metal foil
may be laminated metals, for example, tin-plated copper. The metal
foil may be a doped metal, for example, silver doped with
palladium. Without wishing to be bound by theory, it is believed
that doping silver with palladium inhibits electromigration of
silver. In one embodiment, the metal foil backing is between about
5 .mu.m and about 100 .mu.m thick, in one embodiment between about
5 .mu.m and about 50 .mu.m thick, in another embodiment between
about 5 .mu.m and about 40 .mu.m thick, in another embodiment
between about 5 .mu.m and about 20 .mu.m thick. Thinner metal foil
can be advantageous as it is flexible, though thicker foils can
have higher electrical conductivities. A more flexible backing is
desirable because it can conform to contours on a TCL.
[0074] Adhesive bus bars preferably are stable to visible, UV
light, heat and thermal cycling, and maintain good adhesion when
exposed to same, although heat and/or light may be used to cure the
ECA. In one embodiment, an ECA comprises one or more additives for
stability under exposure to the solar spectrum. Also, by using ECA
formulations, for example epoxy, a rigid framework is provided for
the conductive filler, providing low contact resistance and bulk
conductivity.
[0075] Referring to FIG. 4, a schematic cross-section
representation of an adhesive bus bar, 370, on a transparent
conductive layer (TCL) of an electrochromic device, 400, according
to one embodiment. In the illustrated example, an electrochromic
device 400 comprises a glass substrate, a first and a second TCL,
and therebetween an electrochromic stack. The electrochromic stack
includes an electrochromic layer (not shown) and may also include
an ion conducting (electrically resistive) layer (IC) (not shown).
The electrochromic stack may also include an opposing counter
electrode layer (not shown) also known as an ion storage layer.
This counter electrode layer may or may not be electrochromic. Such
electrochromic devices may be constructed so that the
electrochromic layer is cathodically coloring and the counter
electrode layer is anodically coloring. Though this is not
limiting, it has the advantage that the coloring layers are
complimentary, i.e. they color or bleach concurrently and thus
deeper coloration and more neutral coloration can be achieved.
[0076] The first and second TCL may include transparent conductive
materials, such as metal layers, metal oxides, alloy oxides, and
doped versions thereof. Conductive layers of electrochromic devices
are sometimes referred to as "TCLs" or "TCOs" because they are made
from transparent conductive oxides such as transparent metal
oxides. The term "TCL" is generally used to refer to a wide range
of transparent conductive materials that can be formed as
conductive layers used to deliver potential across the face of an
electrochromic device to drive or hold an optical transition. While
such material layers are sometimes referred to as "TCLs" in this
disclosure, the term encompasses layers with non-oxides as well as
oxides that are transparent and electrically conductive such as
certain very thin metals and certain non-metallic materials.
Transparent conductive material typically has an electronic
conductivity significantly greater than that of the electrochromic
material or the counter electrode material. For example, the
transparent conductive material may have a resistivity of at least
about 100 microohm-cm (also referred to as ".mu..chi.-cm") to about
600 microohm-cm. Further, the transparent conductive material may
have a sheet resistance of at most about 10 ohms/square to about 20
Ohms/square. In certain embodiments, the transparent conductive
material has a sheet resistance of less than 10 ohms/square, or
less than 5 Ohms/square. Examples of transparent conductive
materials include indium tin oxide (ITO), fluorinated tin oxide
(FTO), and aluminum zinc oxide (AZO). In certain aspects, TCLs as
described herein include multi-layer structures. For example, a TCL
may include a first ITO layer, a metal layer, and a second ITO
layer, with the metal layer between the two ITO layers. In one
aspect, a TCL is a multi-layer structure having one or more layers
of transparent conductive materials. Some TCLs may also include a
metallic top and/or bottom conductive layer. In general, however,
the transparent conductive layers of an electrochromic device can
be made of any transparent, electrically conductive material that
is compatible with the electrochromic device stack. The
electrochromic device may include an ion diffusion blocking barrier
layer or layers between the first TCL and the glass substrate, for
example when soda lime glass is the substrate, to prevent sodium
ions from poisoning the device (for example a device that uses
lithium ions for switching).
A. Electrically Conductive Adhesives (ECAs)
[0077] Referring to FIG. 4 adhesive bus bars, 370, comprise an
electrically conductive foil backing, 405, and an electrically
conductive adhesive ("ECA"), 410. In certain embodiments, the ECA
is a pressure sensitive adhesive ("PSA"). Generally speaking a PSA
refers to an adhesive that requires pressure to adhere to a
surface, such as a silicone, polyvinylbutyral, polyvinyl alcohol
based adhesives. An epoxy, for example, is generally not thought of
as a PSA. In certain embodiments, pressure is applied to adhere an
adhesive bus bar to a TCL, therefore, ECA and PSA may be used
interchangeably herein, but it is to be understood that not all
ECAs require pressure for adhesion. For example, in some
embodiments, an ECA is applied to a TCL alone, and then a foil
backing is applied, this may or may not require pressure applied to
the foil backing. Typically, at least minimal pressure is applied
in many embodiments, so the term PSA is often used to describe an
ECA. In one embodiment, only heat is used to adhere an adhesive bus
bar to a TCL. In another embodiment, only pressure is used to
adhere an adhesive bus bar to a TCL. In certain embodiments, heat
and pressure are used to adhere an adhesive bus bar to a TCL.
[0078] Without being held to any particular theory of operation, it
is believed that when an adhesive bus bar is coupled a TCL layer
using an ECA made up of conductive fillers selected to have a
particular dimensional properties, or avoiding conductive fillers
with electromigration issues, for example silver, the penetration
and migration of the ECA into and through any defects that may be
present in the TCL layers can be substantially or completely
eliminated. This enables an electrochromic device, to be
manufactured while avoiding any need to deactivate areas under the
bus bars (to obviate shorting issues). Though, in one embodiment
silver particles are used, as ECA adhesive compositions can avoid
the aforementioned silver problem, for example, epoxy-based ECAs
appear to avoid this issue.
[0079] Generally, an ECA should not outgas post cure and should be
highly impermeable to water and gas transport (for example argon).
In one embodiment, the ECA has a moisture permeability of <0.1 g
H.sub.2O/m.sup.2/day at 25.degree. C. at 100% relative humidity. An
ECA preferably is compatible with primary sealants such as PIB and
spacer materials such as silicone, stainless steel, aluminum and
the like, for example such materials do not compromise cure,
strength, or adhesion of the ECA.
[0080] In some embodiments, an ECA comprises a formulation that is
curable with heat, but that can provide sufficient adhesion of an
adhesive bus bar to an underlying TCL without necessarily requiring
that the ECA be cured. In some embodiments, bus bars 370 can be
coupled to electrochromic device 400 during manufacture of the
device in a sputter coating apparatus, where, as desired or needed
and while in the sputter coating apparatus. In these embodiments,
the ESA may or may not be cured with heat from sputtering
operation(s). In some embodiments, adhesive bus bars 370 may be
coupled to electrochromic device 400 after heat-reliant TCL and
electrochromic deposition manufacturing steps are completed in a
sputter coating apparatus, and as desired or needed, after exiting
the sputter coating apparatus, the ECA formulation may or may not
be cured.
[0081] The ECA formulations described herein are intended to
provide bonding strength between a foil backing and an underlying
TCL layer such that there is little risk that the bus bars will
move or become unstuck during use or fabrication steps, even if the
bus bars are subjected to significant handling and/or manipulation.
In some embodiments, an ECA exhibits good peel strength, but
remains soft and tough enough to withstand thermal cycling and
other harsh environmental conditions that may occur over long
periods of time. In embodiments, in addition to its formulation, an
ECA is formed with a thickness capable of accommodating particular
sized conductive particles and a desired amount of
conductivity/contact resistance, for example, to prevent Argon loss
in an insulated glass unit through the adhesive, as well so as to
provide sufficient peel strength. In one embodiment, an ECA
comprises a thickness that is less than 300 .mu.m, in one
embodiment a thickness that is less than 100 .mu.m, in one
embodiment a thickness that is less than 50 .mu.m, in one
embodiment a thickness that is less than 50 .mu.m, in one
embodiment a thickness that is between about 10 .mu.m and about 50
.mu.m, in yet another embodiment between about 15 .mu.m and about
40 .mu.m, in yet another embodiment between about 20 .mu.m and
about 35 .mu.m. In one embodiment, for a 300 mm long adhesive bus
bar, contact resistance is about 0.0675 ohms. In one embodiment, an
ECA formulation has a pre-cure glass transition temperature
(T.sub.g) in the range of about -50.degree. C. to about -10.degree.
C., in another embodiment in the range of about -10.degree. C. to
about 0.degree. C., in another embodiment in the range of about
0.degree. C. to about 20.degree. C. Since in certain
implementations ECAs are exposed to heat, in one embodiment the
post-cure T.sub.g is above 80.degree. C., in another embodiment
above 90.degree. C., in another embodiment above 100.degree. C. In
some embodiments, the ECA provides a peel strength of at least 25
oz/inch width (about 2.7 N/cm width), typically greater than about
40 oz/inch width (about 4.3 N/cm width). In a one embodiment, an
ECA provides a minimum peel strength of at least 50 N/mm per unit
width.
[0082] In some embodiments, an ECA comprises one or more polymers
and is curable, either by itself or in the presence of one or more
crosslinking components. Alternatively, an ECA may include a
non-reactive polymer blended with one or more crosslinking
components (for example a multifunctional monomer, oligomer, or
polymer) to form a curable ECA formulation. Blends of such reactive
and non-reactive polymers may also be used in other cases.
Exemplary reactive polymers that may be used as the base polymer of
the adhesive formulation include acrylic copolymers that
incorporate epoxy, carboxylic acid, amine, mercaptan, amide,
isocyanate, cyanate ester, allyl, maleimide, acrylate, oxetane,
silicone hydride, alkoxysilane, or other reactive groups pendant to
the polymer backbone or within the polymer backbone. Exemplary
reactive monomers used for acrylic ECA polymers include a glycidyl
methacrylate, a hydroxyethyl acrylate, an allyl methacrylate, an
isocyanatopropyl acrylate, an N-vinylpyrollidone, and an acrylic
acid. Other functional acrylate monomers may also be used.
Exemplary non-reactive polymers include polymers formed from
acrylates such as a butyl acrylate, a methyl acrylate, an
ethylhexyl acrylate, an isooctyl acrylate, and a methyl
methacrylate.
[0083] In some embodiments, ECA formulations can also include
non-acrylic polymers as the base polymer alone or in combination
with acrylic polymers. Both reactive and non-reactive non-acrylic
polymers may be used in the formulation. Suitable non-acrylic
polymers for use in accordance with exemplary embodiments include,
without limitation, phenolic resins, aliphatic polyesters, aromatic
polyesters, polyether polyols, polyester polyols, amine-functional
acrylonitrilebutadiene copolymers, carboxylic acid-functional
acrylonitrilebutadiene copolymers, polyurethanes, polyamides,
rubberized epoxy prepolymers such as carboxyl-terminated liquid
butadiene acrylonitrile (CTBN)-epoxy adducts, and
hydroxyl-functional acrylonitrilebutadiene polymers.
[0084] Reactive or non-reactive base polymers may be synthesized
and some are of the synthesized polymers are commercially
available. For example, acrylic reactive polymers may be
synthesized by free-radical polymerization of monomers in the
presence of a solvent. In such cases, any suitable free radical
initiator may be used; exemplary initiators include, but are not
limited to, peroxy and/or azo compounds. Polyester, polyurethane,
CTBN-epoxy adducts, olefinic and rubber polymers, rubber block
copolymer, and other base polymers can similarly be synthesized by
known methods and some are commercially available.
[0085] Crosslinking components can be blended with non-reactive
base polymers to provide a reactive adhesive formulation, although
crosslinking components may also be used in combination with
reactive base polymers to provide a curable formulation. Typical
crosslinking components are those which include epoxy, acrylate,
oxetane, maleimide, alcohol, mercaptan, isocyanate, cyanate ester,
alkoxysilane, silicon-hydride, allyl, and benzoxazine
functionalities. The crosslinking components containing such
reactive groups may be present as monomers, multifunctional resins,
oligomers, or polymers.
[0086] One suitable class of crosslinking components includes
oligomers such as aliphatic and aromatic urethane acrylates.
Another suitable class includes aliphatic and aromatic epoxy
resins. In some cases, epoxy resins which are not soluble in the
base polymer, and thus exhibit improved latency, may be used. Other
reactive components for use as crosslinking components include, but
are not limited to, multifunctional alcohols, multifunctional
acrylate resins, and multifunctional isocyanates (sometimes in the
form of a chemically blocked isocyanate). While the selection of
crosslinking components is not limited to specific cure
chemistries, exemplary embodiments specifically contemplate
formulations that can be cured by a radical cure, hydroxyl-blocked
isocyanate cure, epoxy-latent amine cure, and an insoluble
epoxy-amine cure, by way of example.
[0087] The amount of crosslinking component may be between about
0.1% by weight to about 70% by weight of the organic solids content
of the formulation (i.e., excluding solvent and fillers), depending
on the level of cure sought to be achieved and whether or not the
crosslinking component is used in combination with an already
reactive polymer or with a non-reactive polymer. More typically,
the crosslinking component is about 0.5% by weight to about 20% by
weight of the organic solids content of the formulation.
[0088] Reactive or non-reactive polymer(s) and/or the crosslinking
component(s) for use with a particular formulation in accordance
with exemplary embodiments may depend upon whether curing or no
curing will be employed. As discussed, a cure profile may be
configured to correspond to that of a fabrication process and/or a
particular step within that fabrication process. In some cases,
there may be multiple instances during, for example, device
fabrication that employs a thermal profile that could, or not,
result in curing, depending on the curing characteristics of the
ECA formulation used to make adhesive bus bars. For example, the
formulation may be selected such that cure occurs in conjunction
with a particular thermal profile that will be employed at a
particular point during the fabrication of the electrochromic
device. One such example is the thermal profile already used to
cure cell encapsulation materials such as ethyl vinyl acetate (EVA)
or polyvinyl butyral (PVB) during cell fabrication, which typically
includes a thermal cure profile of 10-15 minutes at 150-170
.degree. C., which is within the range of temperatures sputter
coaters are capable of applying. In another example, adhesive bus
bars are cured during a thermal anneal of the electrochromic
device. In yet another example, the adhesive bus bars are cured
after the electrochromic device is annealed.
Conductive Particles in ECA
[0089] In one embodiment, an ECA formulation, including any
crosslinking components, is mixed thoroughly with a conductive
filler, optionally using a solvent that facilitates mixing, to form
a resulting reactive conductive adhesive formulation that is used
to couple, both mechanically and electrically, a conductive metal
substrate, for example a foil, to a TCL. FIG. 5 depicts a cross
section of an adhesive bus bar, 370, comprising an electrically
conductive backing ("ECB"), such as a foil backing, 405, and an
ECA, 410, on one face of foil backing 405. The ECA 410 comprises an
adhesive, 415, for example as described herein, and in this
example, conductive particles or filler, 420. Conductive filler 420
may be present at about 0.1% by weight to about 90% by weight
solids of the total adhesive formulation (i.e. excluding the mass
of any optional solvents). Conductive fillers may include metals
such as silver, titanium, tin, zinc, gold, nickel, copper, alloys
thereof, carbon black, carbon fiber, carbon nanotubes, fullerenes,
graphite, metalized carbon fiber, as well as metal-coated glass
beads, metal-coated glass flakes/fibers, and metal-coated nickel
particles, all by way of example. In embodiments, metal coating can
be any conductive metallic material such as tin, silver, nickel,
gold, copper, etc. In some embodiments, conductive filler is
defined by one or more shapes that include, but is not limited to,
spheres, balls, rods, flakes, and elongated and irregular shapes.
In some embodiments, conductive filler particles may also be
defined by one or more dimension that is less than a thickness of
the ECA and/or a dimension large enough to span the entire
thickness of the ECA. In some cases, conductive fillers particles
comprise a width or diameter that does not exceed about 25 um or
that is not less than about 0.5 .mu.m.
[0090] It will be appreciated that conventional additives used with
other known ECA formulations for various purposes may also be
employed. If a solvent is used, it may be a common solvent in some
cases. If desired for processing purposes, the viscosity of the ECA
formulation can be adjusted by adding or removing solvent. Solvents
that may be used include ethyl acetate, toluene, hydrocarbons such
as heptane or hexane, alcohols, and combinations thereof, all by
way of example only. In certain embodiments, an ECA may be applied
to a foil backing with a solvent and the solvent removed. The foil
is then cut into adhesive bus bar strips. The strips are applied to
the TCL with applied pressure and optionally heat to flow the ECA
and/or initiate cross-linking of polymer precursors of the ECA.
[0091] In some embodiments with an adhesive bus bar, an ECA is
coated onto a electrically-conductive substrate such as a
conductive metal for example, tin-coated copper foil. Other
suitable conductive substrates include aluminum foil, silver foil,
copper foil, metalized plastics and conductive scrim, all by way of
example only. In one example, an ECA formulation includes a base
polymer, any crosslinking components, conductive filler(s), any
other fillers, and optional solvent that can be coated onto a
conductive substrate. In some cases, a conductive substrate is in
the form of a conductive tape, metal foil or organic conductive
polymer. An adhesive bus bar can have an aluminum or silver foil
backing, though these metals are prone to electromigration, because
the metal foil is separated from the TCL by the ECA. It is helpful
if the ECA itself does not have electromigration prone metal
particles, such as silver and aluminum; however adhesive
formulations can be used to mitigate problems with such metals
particles, in certain embodiments, as well as doping silver with
electromigration inhibitors such as palladium and/or having larger
grain boundaries in the silver. In one embodiment, an ECA includes
silver particles doped with palladium.
[0092] In one embodiment, a release liner, such as a silicone
release liner, can be laminated over the ECA that is applied to the
conductive substrate until the adhesive bus bar is ready to be
coupled to the TCL layer. At this point, the release liner can be
removed to expose the ECA prior to coupling to the TCL layer. In
other embodiments it may be desirable to apply an ECA solution to a
release liner first, followed by drying to remove excess solvent,
and thereafter laminating the adhesive/liner combination to a
conductive substrate, for example metal foil, of the adhesive bus
bar using a roller or similar device.
[0093] As described previously, for example when metal-based bus
bars are used with an electrochromic device that has its layers
deposited on interior-facing surface, and when the glass is viewed
from the face proximate the bus bar, the metallic color of the bus
bars may visually contrast with the rest of device. It is
undesirable from an aesthetic standpoint to have such bus bars. As
described herein, for example when the ECA formulation is mixed
with carbon black by itself or in combination with other conductive
fillers, the ECA and thus the bus bars can be made to be less
visually discernable. Other benefits and advantages derive from
using adhesive bus bars described herein. For example, adhesive bus
bars can be fabricated to have more uniform dimensions and improved
processing yields as compared to ink based bus bars whose
variations in whose dimensions are more difficult to detect. In one
embodiment, adhesive bus bars comprise a width between about 1 mm
and 5 mm and a thickness of between 35 .mu.m and 3.5 .mu.m.
Compared to ink-based bus bars, adhesive bus bars in the form of
tape can be manufactured with a width that varies less along its
length, which leads to improved product performance variation and
reduced reliability risk. A substantially constant width as can be
provided by adhesive bus bars also enables more constant electrical
conductivity along their length and as a result enables more
uniform voltage across TCL layers, which in turn translates to more
uniform coloration of the electrochromic window.
[0094] Also, compared to use of silver ink based bus bars, adhesive
bus bars eliminate busbar pooling and residue that can happen with
a silver ink bus bar. Such pooling can also limit product yields.
Further, use and cost of semi-precious metals like silver can be
eliminated if desired via the use of common metals such as tin and
copper in adhesive bus bars. Because in some embodiments adhesive
bus bars can be used without curing, additional ovens may not be
needed. Further, in an embodiment where a tin metal surface is
applied over an underlying metal foil, adhesive bus bars can be
made to be more resistant to environmental degradation such as
moisture corrosion and UV exposure, and can be made to be more
thermally and mechanically robust by being inherently resilient to
cohesive failure, flaking, or cracking that can occur in an ink
based system. Also, when conductive metal foil is used, subsequent
electrical connections thereto can be made more easily via
soldering, which soldering to ink based bus bars can sometimes
cause ink delamination or ink melting. As an example, a tin plating
can also aid in soldering electrical connections to the adhesive
bus bar. In one embodiment, a solder joint is made to an adhesive
bus bar without substantially changing the electrical conductivity
between the TCL and the ECA at the solder joint.
[0095] One embodiment pertains to an adhesive bus bar including an
electrically conductive adhesive (ECA) as described herein and an
electrically conductive backing as described herein.
[0096] Certain embodiments pertain to adhesive bus bars that
include an electrically conductive adhesive (ECA) and an
electrically conductive backing having at least one of a metal, a
metallized plastic, a metallized woven fabric, a carbon fiber, an
alloy, and a metallized carbon fiber. In one embodiment, the
electrically conductive adhesive is between about 10 .mu.m and
about 50 .mu.m thick. In another embodiment, the electrically
conductive adhesive has a post-cure T.sub.g is above 80.degree. C.
In another embodiment, the electrically conductive adhesive has a
peel strength of at least about 2.7 N/cm width. In another
embodiment, the electrically conductive adhesive includes a tinting
agent, e.g., at least one of carbon black, graphite, carbon
nanotubes and fullerenes.
[0097] In some embodiments pertaining to adhesive bus bars, the
electrically conductive backing includes a metal foil. The metal
foil may include at least one of silver, aluminum, titanium, tin,
zinc, gold, nickel, copper and alloys thereof. The metal foil may
be a laminated metal, for example, tin-plated copper. The metal
foil may be a doped metal or a doped alloy. For example, the metal
foil may be silver doped with palladium. In one embodiment, the
metal foil is between about 5 .mu.m and about 50 .mu.m thick.
In some embodiments of adhesive bus bars, the electrically
conductive adhesive includes an adhesive and a conductive filler.
In one embodiment, the conductive filler is selected from the group
consisting of silver, gold, nickel, copper, carbon black, carbon
fiber, metalized carbon fiber, carbon nanotubes, fullerenes,
graphite, metal-coated glass beads, metal-coated glass flakes,
metal-coated glass fibers, and metal-coated nickel particles. In
another embodiment, the conductive filler includes metal-coated
particles where a metal coating on the metal-coated particles is
selected from the group consisting of tin, silver, gold, copper and
nickel. In another embodiment, the conductive filler includes
particles having shapes selected from the group consisting of
spheres, rods, flakes, and irregular shapes. In another embodiment,
the conductive filler includes particles having a maximum dimension
that does not exceed 25 .mu.m or a minimum dimension that is not
less than about 0.5 .mu.m. In another embodiment, the conductive
filler includes particles having at least one of silver, aluminum,
titanium, tin, zinc, gold, nickel, copper and alloys thereof. In
another embodiment, the conductive filler includes particles
comprising a laminated metal. In another embodiment, the conductive
filler includes particles comprising tin-plated copper. In another
embodiment, the conductive filler includes particles comprising
doped metal (e.g., silver doped with palladium) or doped alloy. For
example, the dope metal may e silver doped with palladium. In
another embodiment, the adhesive is an a-stage adhesive or a
b-stage adhesive. In another example, the adhesive is an epoxy.
B. Application of Adhesive Bus Bar to TCL
[0098] In one embodiment, adhesive bus bars are applied to a TCL
with applied pressure. In another embodiment, both pressure and
heat are used to apply an adhesive bus bar to a TCL. The heat is
used to flow the ECA and/or initiate cross-linking of polymer
precursors of the ECA. FIG. 6 depicts a cross section of an
assembly, 600, comprising an adhesive bus bar, 370, being adhered
to a TCL. The TCL is part of an electrochromic device (not shown).
Force is applied, for example, using a press, roller or similar
device. Pressure alone may be sufficient to adhere adhesive bus bar
370 to the TCL, but in some embodiments heat is also used. Pressure
may be required to make good electrical contact between the foil
backing and the TCL, but in certain embodiments heat serves to flow
the adhesive portion 415 sufficiently to make it tacky and adhere
to the TCL. In one embodiment, heat is applied to initiate reaction
between polymer precursors in the ECA. For example, as described
herein, a two part epoxy-based ECA is used. When the pressure and
heat are applied to the adhesive bus bar, the ECA flows and the
precursors sufficiently mix to start a chemical chain reaction to
polymerize the adhesive portion 415. Conductive particles (filler)
420 have dimensions and/or are of sufficient density in the ECA to
make electrical connection between the foil and the TCL.
[0099] In one embodiment, the ECA comprises an a-stage or a b-stage
adhesive. An "a-stage" adhesive is one that is cured in a single
step or stage. A "b-stage" adhesive is one that is cured in two
steps or stages, for example components of the adhesive are applied
and partially cured and/or solvents removed "predried," followed by
a full cure at a later stage. Thus, predrying can comprise simply
removing solvents or other carriers to decrease viscosity and/or
literally dry out polymer precursors or polymers, and/or partially
cure polymer precursors. One example of an a- or b-stage adhesive
is an epoxy-based adhesive. In one embodiment, the epoxy-based
adhesive is an a-stage epoxy. In one embodiment the epoxy-based
adhesive is a b-stage epoxy. A "b-stage epoxy" is a one component
epoxy system, using a latent (low reactivity) curing agent. Thus, a
b-stage epoxy can be partially cured (sometimes referred to as
"pre-dried"), as an initial stage after being applied onto one
substrate/surface, for example a foil backing as described herein.
It can, for example at a later time, be completely cured under heat
and pressure. This is significantly different from an "a-stage
epoxy" that is provided in a one or two component format and, is
cured in one step at ambient or elevated temperatures. An advantage
of a-stage epoxy ECA's is that they do not require pressure to
cure. Thus one embodiment is application of an adhesive bus bar to
a TCL using only heat. Certain methods described herein use b-stage
epoxy ECA, for example, to enable processing advantages. In one
embodiment, the b-stage expoxy ECA is applied to a foil backing and
partially cured (predried). One advantage of this approach is that
a protective peel away cover does need to be applied to the ECA
during storage, although in one embodiment it is applied. In one
embodiment a b-stage epoxy ECA is applied to a foil backing and
partially cured (predried) in one location, and its final cure in
another location, upon application to the TCL. In one embodiment, a
b-stage epoxy ECA is applied to the TCL, then predried, and
thereafter a foil backing is applied to the ECA with heat and/or
pressure to form an adhesive bus bar and adhere it to the TCL
concurrently. The latter method has the advantage that an ECA can
be applied to the TCL first, and the foil backing chosen at a later
time, and for example, different foil backings can be applied to
the same electrochromic window if desired. This adds flexibility to
processing. In one embodiment, a a-stage epoxy ECA is applied to a
TCL, followed by application of a foil backing and curing of the
a-stage epoxy ECA. The application of foil to an ECA on a TCL and
heating to cure the ECA can be concurrent or done serially.
Ultraviolet light or other light energy (for example laser energy)
may be applied to an ECA, through the TCL, with or without heat and
applied pressure, to cure an ECA. Adhesive bus bar applications
described herein can comprise using UV or other light energy alone
or in combination with heat and/or pressure. Applied heat described
herein may be supplied using and oven, a heat lamp, a laser, a hot
roller, a hot press and the like.
[0100] When curing an ECA with heat, the heat should be compatible
with the electrochromic device in question. For all solid state and
inorganic electrochromic devices, for example sputtered metal oxide
type, cure temperatures up to 350.degree. C. may be compatible. In
one embodiment an ECA is cured at between about 80.degree. C. and
about 400.degree. C., in another embodiment between about
100.degree. C. and about 350.degree. C., in another embodiment
between about 150.degree. C. and about 250.degree. C., in another
embodiment between about 150.degree. C. and about 200.degree. C.,
in yet another embodiment between about 160.degree. C. and about
180.degree. C. In one embodiment, curing time is between about 1
minute and about 60 minutes, in another embodiment between about 5
minutes and about 30 minutes, in yet another embodiment, between
about 10 minutes and 20 minutes, in yet another embodiment about 15
minutes. It is understood that the above temperature ranges and
times may be combined in any combination, and each such combination
is an embodiment. For example, in one embodiment an ECA is cured at
a temperature of between about 150.degree. C. and about 200.degree.
C., for between about 10 minutes and about 20 minutes.
[0101] Pressure, if applied during application of an adhesive bus
bar to a TCL as described herein, can be between about 5 psi and
about 100 psi. In one embodiment, pressure is applied to adhere an
adhesive bus bar to a TCL, where the pressure is between about 5
psi and about 100 psi, in one embodiment between about 10 psi and
about 50 psi, in one embodiment between about 10 psi and about 25
psi. In one embodiment, a b-stage epoxy ECA is used, where a first
pressure and heat are applied to melt ("wet") the ECA, followed by
a cure without pressure, at the same or different temperature as
the melt stage Certain embodiments pertain to methods of
fabricating an electrochromic device include: (a) applying an
electrically conductive adhesive to a transparent conductive layer
of the electrochromic device, (b) applying an electrically
conductive backing to the electrically conductive adhesive, and (c)
applying a pressure (e.g., applied using a press or a roller)
and/or a heat (e.g., applied using at least one of an oven, a heat
lamp, a laser, a hot roller and a hot press) to the electrically
conductive backing where the electrically conductive adhesive is
sandwiched between the transparent conductive layer and the
electrically conductive backing. The operations may be performed in
different orders. For example, the operations may be performed in
the order (a), then (b), and then (c). As another example, the
operations may be performed in the order (b), then (a), and then
(c). The conductive adhesive may include a two-part epoxy, an
a-stage adhesive such as a pressure sensitive adhesive, or a
b-stage adhesive such as an epoxy. If the conductive adhesive
includes an a-stage adhesive, in certain embodiments pressure may
not be applied or heat may not be applied. If the conductive
adhesive includes a b-stage adhesive, the b-stage adhesive may be
predried either on the electrically conductive backing or on the
transparent conductive layer, prior to (c), and fully cured during
(c). If the b-stage adhesive is an epoxy, the epoxy may be applied
to the electrically conductive backing and predried, prior to (c),
or, the epoxy may be applied to the transparent conductive layer
and predried, prior to (c). In one example where the-stage adhesive
is an epoxy, the electrically conductive backing is a metal foil.
In one embodiment, operation (c) also includes applying an
ultraviolet light to the electrically conductive adhesive, e.g.,
applying the pressure and the ultraviolet light, but not the heat,
to the electrically conductive adhesive. In another embodiment,
operation (c) includes applying the pressure and the heat to flow
the electrically conductive adhesive and/or initiate cross-linking
of polymer precursors of the electrically conductive adhesive.
[0102] In some of these methods, operation (c) includes applying at
least heat to the electrically conductive backing. In one
embodiment, applying heat includes heating to between about
80.degree. C. and about 400.degree. C., in another embodiment,
applying heat includes heating to between about 100.degree. C. and
about 350.degree. C., in another embodiment, applying heat includes
heating to between about 150.degree. C. and about 250.degree. C.,
and in another embodiment, applying heat includes heating to
between about 160.degree. C. and about 180.degree. C. In one
embodiment, applying heat includes heating for between about 1
minute and about 60 minutes, in another embodiment, applying heat
includes heating for between about 5 minutes and about 30 minutes,
in another embodiment, applying heat includes heating for between
about 10 minutes and about 20 minutes. In one embodiment, applying
heat includes heating to between about 150.degree. C. and about
200.degree. C., for between about 10 minutes and about 20 minutes.
In some of these methods, operation (c) includes applying at least
pressure to the electrically conductive backing. In one embodiment,
applying the pressure includes applying pressure at between about 5
psi and about 100 psi, in another embodiment, applying the pressure
includes applying pressure at between about 10 psi and about 50
psi, in another embodiment, applying the pressure includes applying
pressure at between about 10 psi and about 25 psi. In one
embodiment, a first pressure may be applied and heat is applied in
order to melt the electrically conductive adhesive, followed by a
cure without pressure at the same or different temperature as is
applied during the first pressure application.
C. Adhesive Bus Bar Configurations
[0103] Various embodiments comprise adhesive bus bar configurations
on electrochromic windows in the form of insulated glass units.
Certain electrochromic insulated glass units, for example those
manufactured by View, Inc. of Milpitas, Calif., U.S.A., maximize
the viewable area of the electrochromic window. Besides making the
largest electrochromic windows ever made, for example 6
feet.times.10 feet (1.8 m.times.3.0 m), the viewable area is
maximized in any size electrochromic insulated glass unit by
configuring the bus bars outside of the viewable area, for example
within the primary seal, or "under the spacer" as it is sometimes
termed. Advantages of this configuration also include protecting
the bus bar from moisture that would be encountered in the
secondary sealing volume of an insulated glass unit (for example
structural silicone is not an efficient moisture barrier). Further
details of such configurations are described, for example, in U.S.
Pat. No. 9,958,750. As described herein, adhesive bus bars can be
camouflaged to blend in with their background, the primary sealant
and/or the spacer, by virtue of adjusting the color and other
optical properties of the ECA. Further, there are application
advantages as described herein, for example, as compared to silver
ink bus bars, for example tighter control over application
tolerances, process integration with electrochromic window
fabrication, and the like.
[0104] Certain embodiments relate to how adhesive bus bars are
configured relative to other components of electrochromic insulated
glass units. FIG. 8 depicts an adhesive bus bar configuration, 800,
for an electrochromic insulated glass unit. A transparent
substrate, for example a glass substrate, 805, has a spacer, 720,
and adhesive bus bars, 370. In this example, the spacer and
substrate are rectangular. In FIGS. 8-10, the bus bars and spacer
are depicted with contrast so as to distinguish the components for
discussion purposes, though as described herein, one embodiment is
to camouflage or otherwise color match the bus bar and spacer
and/or primary seal adhesive. Adhesive bus bars 370 are along their
length arranged under the spacer. In this example, the bus bar on
the right follows the length of the spacer and is registered with
the spacer. A small portion of the right bus bar emanates from the
spacer to make electrical connection with a wire or other
connection, for example a wire solder joint, a flexible circuit
solder joint and the like, at an area 820. Area 820 is in the
secondary sealing area of the insulated glass unit. In this
description, an "area" may be a portion of the secondary sealing
area, on one of two substrates of an insulated glass unit, where
two adhesive bus bars end proximate each other, for lead attach.
That is, when two bus bars are described as terminating at the same
area, then it applies that the area is a common area where the ends
of the respective bus bars are proximate each other (while in some
embodiments "area" is used in the context of where a bus bar
terminates in the secondary seal area, where each bus bar
terminates in a separate area, thus not necessarily proximate each
other, and in those embodiments each area is distinctly specified,
for example, a first area, a second area, etc.). In one embodiment,
where bus bars terminate proximate each other, the area is between
about 1 square inch and about 10 square inches, in another
embodiment between about 1 square inch and about 7 square inches,
in another embodiment between about 2 square inches and about 5
square inches, in another embodiment between about 2 square inches
and about 4 square inches, in another embodiment between about 2
square inches and about 3 square inches. The bus bar on the left
side of the figure also emanates from under the spacer at the
bottom of the figure, but does not end there. Rather, the bus bar
makes a turn at a vertex or corner, 810, and traverses the width of
the glass in the secondary seal area and ends proximate the other
bus bar at area 820. This configuration has the advantage that
minimal bus bar area is used to emanate from under the spacer, only
at two places, one for each bus bar; and, the ends of the bus bars
end at a common area, which makes attachment, for example
soldering, of leads more facile.
[0105] Certain electrochromic insulated glass units or
electrochromic IGUs include a transparent substrate with an
electrochromic device coating thereon, a spacer sandwiched between
the transparent substrate and another substrate, a first bus bar,
and a second bus bar. The first bus bar includes a first leg and a
second leg. The first leg includes a first portion between the
transparent substrate and the spacer that spans along substantially
the entire length of a first side of the spacer. The first leg also
includes a second portion that emanates from between the
transparent substrate and the spacer to extend to a vertex of the
first bus bar that lies outside the spacer's outer perimeter at a
second side of the spacer. The second leg extends from the vertex
and ends at an area on and proximate a corner of the transparent
substrate. The second bus bar includes a first portion that is
between the transparent substrate and the spacer and that spans
substantially the entire length of a third side. The third side is
opposite the first side of the spacer. The second bus bar also
includes a second portion that emanates from between the
transparent substrate and the spacer and that terminates at the
area on and proximate the corner of the transparent substrate. The
transparent substrate and the spacer are rectangular. In one
embodiment, the electrochromic device coating (e.g., an all solid
state and inorganic electrochromic device coating) is a monolithic
device whose perimeter edges lie between the spacer and the
transparent substrate. In one embodiment, the area is between about
1 square inch and about 10 square inches, in another embodiment,
the area is between about 2 square inches and about 5 square
inches, and in another embodiment, the area is between about 2
square inches and about 3 square inches.
[0106] In some of these embodiments with electrochromic IGUs, the
first and second bus bars are adhesive bus bars. In one embodiment,
each adhesive bus bar includes an electrically conductive adhesive
with a metal foil backing. In another embodiment, the vertex is
fabricated by adhering two adhesive bus bar portion ends with or
without pressure and/or heat. For example, the two adhesive bus bar
portion ends may be soldered together, e.g., using laser,
ultrasonic or conventional heating to make the joint. In one
embodiment, the vertex is fabricated by at least one of bending,
folding, soldering, welding and brazing.
[0107] Referring to FIGS. 20A-C, a vertex or corner can be
fabricated in a number of ways, illustrated by non-limiting
examples here. It is noted that in this application, the terms
"arm" and "leg" are used for portions of a bus bar that extend to
or from a vertex. This is simply a convention, for example when
describing a particular bus bar having a first leg and and second
leg, etc.; where there is another bus bar in relation to the same
electrochromic window, the second bus bar's analogous features may
be called "arms" rather than legs simply to avoid confusion.
Referring to FIG. 20A, an adhesive bus bar vertex, 810, is made by
overlapping ends of two adhesive bus bar portions, 370a and 370b,
to form adhesive bus bar 370. At the vertex 810, the ECA may be the
only means of attachment force. Heat and/or pressure, as described
herein, may be used to adhere the two adhesive bus bar portions at
the vertex. In one embodiment, the vertex is soldered, for example
using laser, ultrasonic or conventional heating to make the joint.
In one embodiment, the adhesive bus bar portions are tin plated
copper to facilitate the soldering bond. In another embodiment, the
vertex is spot welded or braised.
[0108] In other embodiments, an adhesive bus bar vertex is
fabricated using a single adhesive bus bar, rather than two
portions. Non-limiting examples of these embodiments are described
in FIGS. 20B and 20C. Referring to FIG. 20B, a linear strip of
adhesive bus bar, 370, is made by bending the adhesive bus bar
along an axis perpendicular to the face of the bus bar (for
example, parallel with the glass upon which and while it is being
adhered), as indicated by the curved dotted arrow, to form vertex
810 as indicated by reference number 2000. In such a fabrication
method, the adhesive backing is stretched on the outer radius of
the vertex and compressed on the inner radius of the vertex. In
another embodiment, referring to 2050, a linear strip of adhesive
bus bar, 370, is made by bending the adhesive bus bar along an axis
perpendicular to the face of the bus bar (for example, parallel
with the glass upon which and while it is being adhered), as
indicated by the curved dotted arrow, along with forming the inner
radius (making folds) to facilitate forming vertex 810. In another
embodiment, not depicted, rather than forming, notches are cut
along one side of the strip to facilitate bending to form the
vertex.
[0109] Referring to FIG. 20C, a linear strip of adhesive bus bar,
370, is made by folding the adhesive bus bar in order to form the
vertex. For example, as indicated by the three dotted fold lines,
the linear strip is folded out of the plane of the backing on one
side along the middle of the three dotted lines, as indicated by
the dotted double headed arrow. In this example, the vertex is a 90
degree angle, so the flap formed by the folding is flatted to form
vertex 810 as indicated by reference number 2099. The flap may be
held down to the backing by an ECA, with or without pressure and/or
heat, or soldering, or welding as described herein. The vertices as
described in FIGS. 20B-C have the advantage of using a continuous
strip of adhesive bus bar and thus ensure good electrical
connection.
[0110] In one embodiment, vertex 810 is made by bending the
adhesive bus bar along an axis perpendicular to the face of the bus
bar parallel with the glass. In other words, at the end of a first
leg (or arm) of the bus bar, the bus bar is curved or folded to
make a turn, for example a 90 degree turn, in order to extend
further in a direction orthogonal to the first leg of the bar, the
extension being a second leg of the bus bar. Thus a vertex can be a
sharp well-defined angle, a curve or the like. Generally speaking,
a vertex is a point or portion of a bus bar where the bus bar
changes direction along a surface upon which it is mounted. In
another embodiment, vertex 810 is made by soldering two sections of
adhesive bus bar at the vertex. As described, adhesive bus bars may
be tin plated to aid in soldering, as well as making them corrosion
resistant. In one embodiment, at least that portion of an adhesive
bus bar that is outside the primary seal is tin plated. In this
example, one bus bar has one vertex and the other bus bar has none.
In another embodiment, vertex 810 is made by overlapping portions
of adhesive bus bars, as the ECA provides sufficient electrical
connectivity and adhesion between overlapping bus bar portions.
Pressure and/or heat may be applied to vertex 810 as described
herein. Different adhesive bus bar compositions can be used for the
portions, for example the portion along the width in the secondary
seal may be tin plated copper, while the portions substantially
under the spacer may be copper.
[0111] In embodiments described herein, any portion, leg, arm,
vertex of an adhesive bus bar that is between the spacer and the
glass can be used to power an electrochromic device. That is,
embodiments include configurations where the electrochromic
device's entire perimeter edge is between the spacer and the
transparent substrate. Depending on how the electrochromic device
is patterned and fabricated, only one leg of an adhesive bus bar
can reside on a transparent conductive layer of the electrochromic
device, or for example two legs, including the vertex between them,
can also reside on the transparent conductive layer and power the
electrochromic device; or for example, all three legs (and two
vertices) can be configured, at least in part, on the transparent
conductor layer, and power the electrochromic device. For example,
in the embodiment illustrated in FIG. 8, those portions of the
adhesive bus bars between the spacer and the substrate are used to
power an electrochromic device where the entire perimeter edge of
the device is also between the spacer and the substrate.
[0112] FIG. 9 depicts an adhesive bus bar configuration, 900, for
an electrochromic insulated glass unit. A glass substrate, 805, has
a spacer, 720, and adhesive bus bars, 370. Adhesive bus bars 370
are along their length arranged under the spacer. In this example,
one bus bar has two vertices, and the other has none. In this
example, the bus bar on the right follows the length of the spacer
and is registered with the spacer. A small portion of the right bus
bar emanates from the spacer at area 820. The bus bar on the left
side of the figure also emanates from under the space, but first
makes a turn at 810a at the bottom of the figure, still under the
spacer, and then makes a second turn at a vertex or corner, 810b,
then emanates from under the spacer, proximate the other bus bar at
area 820. This configuration has the advantage that minimal bus bar
area is used to emanate from under the spacer, only at two places,
one for each bus bar; and, the ends of the bus bars end at a common
area, which makes attachment, for example soldering, of leads more
facile. It also has the advantage that the portion of the bus bar
on the left that runs along the width of the spacer, unlike in FIG.
8 running along the secondary seal area, continues to run under the
spacer. This leaves less bus bar exposed to the secondary seal
area. The vertices 810a and 801b are made the same way as described
above; although, in one embodiment different vertices, for example
along a single bus bar and/or under the spacer vs in the secondary
seal area, may be made using different methods, for example one is
soldered the other is overlapping adhesive bus bar portions. In
this example, the longest portions of the bus bars are used to
power an electrochromic device where the entire perimeter edge of
the electrochromic device is also between the spacer and the
substrate. Optionally, the second leg of the first bus bar (on the
left) is also used to power the electrochromic device.
[0113] Of note are configurations where two bus bars are in close
proximity and each powering the electrochromic device. Care must be
taken to avoid hot spots forming during powering of the device.
Avoidance of hot spots is described in U.S. patent application Ser.
No. 13/452,032 (now U.S. Pat. No. 10,429,712), filed on Apr. 20,
2010 and titled "ANGLED BUS BAR," which is hereby incorporated by
reference in its entirety. For example, area 820 shows the ends of
the first and second bus bars in relatively close proximity; this
is only for illustration purposes. If for example both the first
and second leg of the bus bar in FIG. 9 are used to power the
device, that is, they are both on the transparent conductive layer
of the device, it can be the case that area 820 is larger, that is,
the ends for lead attach are further from each other than implied
by the figure. Thus embodiments where two bus bar ends terminate in
"an area" using the metrics described herein, for example, where
the area is between about 1 square inches and about 10 square
inches; the distance between the leads ends will vary, but in such
embodiments will fall within the described area. For example, the
area of 10 square inches may be 1/2 inch wide and 20 inches long,
and the lead ends on opposite ends of the area. In other
embodiments, the lead ends are relatively close, for example where
the area is 1 square inch having dimensions 1/2 inch wide and 2
inches long, or in another example where the area is 1 square inch
having dimensions 3/4 inch wide and 11/3 inches long.
[0114] Certain electrochromic insulated glass units or
electrochromic IGUs include a transparent substrate with an
electrochromic device coating thereon, a spacer sandwiched between
the transparent substrate and another substrate, a first bus bar,
and a second bus bar. The first bus bar includes a first leg, a
second leg, and a third leg. The first leg is between the
transparent substrate and the spacer. The first leg spans along
substantially the entire length of a first side of the spacer and
extends to a first vertex between the transparent substrate and the
spacer. The second leg extends from the first vertex between the
transparent substrate and the spacer and extends along a second
side of the spacer and to a second vertex between the transparent
substrate and the spacer. The third leg of the first bus bar
extends from the second vertex. This third leg includes a first
portion emanating from between the transparent substrate and the
spacer on the second side and outside of the spacer's outer
perimeter and extends to an area proximate a corner of the
transparent substrate. The second bus bar includes a first portion
that is between the transparent substrate and the spacer and spans
along substantially the entire length of a third side of the
spacer, opposite the first side. The second bus bar also includes a
second portion that emanates from between the transparent substrate
and the spacer and terminates at the area proximate the corner of
the transparent substrate. The transparent substrate and the spacer
are rectangular. In one embodiment, the electrochromic device
coating (e.g., an all solid state and inorganic electrochromic
device coating) is a monolithic device whose perimeter edges lie
between the spacer and the transparent substrate. In one
embodiment, the area is between about 1 square inch and about 10
square inches, in another embodiment, the area is between about 2
square inches and about 5 square inches, and in another embodiment,
the area is between about 2 square inches and about 3 square
inches. In some of these embodiments with electrochromic IGUs, the
first and second bus bars are adhesive bus bars. In one embodiment,
each adhesive bus bar includes an electrically conductive adhesive
with a metal foil backing. In another embodiment, at least one of
the first and second vertexes are fabricated by adhering two
adhesive bus bar portion ends with or without pressure and/or heat.
For example, the two adhesive bus bar portion ends may be soldered
together. In one embodiment, at least one of the first and second
vertexes are fabricated by at least one bending, folding,
soldering, welding and brazing.
[0115] FIG. 10 depicts an adhesive bus bar configuration, 1000, for
an electrochromic insulated glass unit. A glass substrate, 805, has
a spacer, 720, and adhesive bus bars, 370. Adhesive bus bars 370
are along their length arranged under the spacer. In this example,
each of two bus bars has a single vertex. In this example, the bus
bar on the right follows the length of the spacer and is registered
with the spacer, but includes a vertex, 810c. A small portion of
the right bus bar emanates from the spacer at area 820. The bus bar
on the left side of the figure also emanates from under the space,
but first makes a turn at 810a at the bottom of the figure, still
under the spacer, traverses along the width of the spacer then
emanates from under the spacer, proximate the other bus bar at area
820. This configuration has the advantage that minimal bus bar area
is used to emanate from under the spacer, only at two places, one
for each bus bar; and, the ends of the bus bars end at a common
area, which makes attachment, for example soldering, of leads more
facile. It also has the advantage that the portion of the bus bar
on the left that runs along the width of the spacer, continues to
run under the spacer. The vertices 810a and 801c are made the same
way as described above, including differing methods of making
vertices in a single insulated glass unit. In this example, the
longest portions of the bus bars are used to power an
electrochromic device where the entire perimeter edge of the
electrochromic device is also between the spacer and the substrate.
Optionally, the second leg of the first bus bar (on the left) is
also used to power the electrochromic device.
[0116] Certain electrochromic insulated glass units or
electrochromic IGUs include a transparent substrate with an
electrochromic device coating thereon, a spacer sandwiched between
the transparent substrate and another substrate, a first bus bar,
and a second bus bar. The first bus bar includes a first leg and a
second leg. The first leg of the first bus bar is between the
transparent substrate and the spacer. This first leg spans along
substantially the entire length of a first side of the spacer and
extends to a first vertex between the transparent substrate and the
spacer. The second leg extends from the first vertex that is
between the transparent substrate and the spacer. The second leg
extends along a second side of the spacer. The second leg has a
portion that emanates from between the transparent substrate and
the spacer on a third side of the spacer opposite the first side.
This portion of the second leg extends to an area on and proximate
a corner of the transparent substrate outside the spacer's outer
perimeter. The second bus bar includes a first arm and a second
arm. The first arm is between the transparent substrate and the
spacer. The first arm spans along substantially the entire length
of the third side of the spacer and extends to a first corner
between the transparent substrate and the spacer. The second arm
extends from the first corner and includes a portion that emanates
from between the transparent substrate and the spacer on the third
side of the spacer and terminates at the area of the transparent
substrate. The transparent substrate and the spacer are
rectangular. In one embodiment, the electrochromic device coating
(e.g., an all solid state and inorganic electrochromic device
coating) is a monolithic device whose perimeter edges lie between
the spacer and the transparent substrate. In one embodiment, the
area is between about 1 square inch and about 10 square inches, in
another embodiment, the area is between about 2 square inches and
about 5 square inches, and in another embodiment, the area is
between about 2 square inches and about 3 square inches.
[0117] In some of these embodiments with electrochromic IGUs, the
first and second bus bars are adhesive bus bars. In one embodiment,
each adhesive bus bar includes an electrically conductive adhesive
with a metal foil backing. In another embodiment, each of the first
vertex and the first corner are fabricated by adhering two adhesive
bus bar portion ends with or without pressure and/or heat. For
example, the first vertex and the first corner can be fabricated by
overlapping ends of two adhesive bus bar portions. Heat and/or
pressure, as described herein, may be used to adhere the two
adhesive bus bar portions. In one embodiment, the two adhesive bus
bar portion ends are soldered together, e.g., using laser,
ultrasonic or conventional heating to make the joint. In some
embodiments, the first vertex and the first corner are fabricated
by at least one of bending, folding, soldering, welding and
brazing.
[0118] FIG. 11 depicts an adhesive bus bar configuration, 1100, for
an electrochromic insulated glass unit. A glass substrate, 805, has
a spacer, 720, and adhesive bus bars, 370. Adhesive bus bars 370
are along their length arranged under the spacer. In this example,
each of two bus bars has two vertices and are symmetrical, in this
example mirror images of each other. In this example, each bus bar
has a first leg that follows the length of the spacer and is
registered with the spacer, but on opposing sides of the spacer.
The first leg spans to a first vertex, 810a. A second leg spans
from the vertex to second vertex, 810b. A small portion of each bus
bar emanates from the spacer at area 820. This configuration has
the advantage that minimal bus bar area is used to emanate from
under the spacer, only at two places, one for each bus bar; and,
the ends of the bus bars end at a common area, which makes
attachment, for example soldering, of leads more facile. In this
example, the longest portions of the bus bars are used to power an
electrochromic device where the entire perimeter edge of the
electrochromic device is also between the spacer and the substrate.
Optionally, the second leg of each bus bar is also used to power
the electrochromic device.
[0119] Certain electrochromic insulated glass units or
electrochromic IGUs include a transparent substrate with an
electrochromic device coating thereon, a spacer sandwiched between
the transparent substrate and another substrate, and a first bus
bar and a second bus bar. Each of the bus bars includes a first
leg, a second leg, and a third leg. The first leg is between the
transparent substrate and the spacer. The first leg of each of the
first and second bus bars spans along substantially the entire
length of a first side and a second side of the spacer,
respectively. The first and second sides of the spacer are opposite
and parallel to each other. The first leg extends to a first vertex
of the respective bus bar. The first vertex is between the
transparent substrate and the spacer. The second leg of each bus
bar is between the transparent substrate and the spacer and extends
from the first vertex along a third side of the spacer, between the
first and second sides, and extends to a second vertex of the
respective bus bar. The second vertex is between the transparent
substrate and the spacer and also along the third side of the
spacer. The third leg of each bus bar extends from the second
vertex of the respective bus bar. This third leg has a portion that
emanates from between the transparent substrate and the spacer and
that extends to an area on the transparent substrate outside the
spacer's outer perimeter on the third side of the spacer. The
transparent substrate and the spacer are rectangular. In one
embodiment, the electrochromic device coating (e.g., an all solid
state and inorganic electrochromic device coating) is a monolithic
device whose perimeter edges lie between the spacer and the
transparent substrate. In one embodiment, the area is between about
1 square inch and about 10 square inches, in another embodiment,
the area is between about 2 square inches and about 5 square
inches, and in another embodiment, the area is between about 2
square inches and about 3 square inches. In some of these
embodiments with electrochromic IGUs, the first and second bus bars
are adhesive bus bars. In one embodiment, each adhesive bus bar
includes an electrically conductive adhesive with a metal foil
backing. In another embodiment, at least one of the first and
second vertexes is fabricated by adhering two adhesive bus bar
portion ends with or without pressure and/or heat. In another
embodiment, at least one of the first and second vertexes is
fabricated by at least one bending, folding, soldering, welding and
brazing.
[0120] FIG. 12 depicts an adhesive bus bar configuration, 1200, for
an electrochromic insulated glass unit. A glass substrate, 805, has
a spacer, 720, and adhesive bus bars, 370. Adhesive bus bars 370
are along their length arranged under the spacer. In this example,
each of two bus bars has only one vertex and are symmetrical. In
this example, each bus bar has a first leg that follows the length
of the spacer and is registered with the spacer, but on opposing
sides of the spacer. The first leg spans to a first vertex, 810. A
second leg spans from the vertex to emanate from under the spacer,
each at a first and second area, respectively, in the secondary
seal area on the transparent substrate (for wire lead attach, for
example, by soldering). The first and second areas are diagonally
opposed, proximate distinct corners of the transparent substrate.
This configuration has the advantage that minimal bus bar area is
used to emanate from under the spacer, only at two places, to make
electrical connections, for example wire attachment, for example
soldering of leads. In this example, the first leg and second legs
of the bus bar are used to power an electrochromic device where the
entire perimeter edge of the electrochromic device is also between
the spacer and the substrate.
[0121] Certain electrochromic insulated glass units or
electrochromic IGUs include a transparent substrate with an
electrochromic device coating thereon, a spacer sandwiched between
the transparent substrate and another substrate, and a first bus
bar and a second bus bar. Each of the bus bars includes a first leg
and a second leg. The first leg is between the transparent
substrate and the spacer. The first leg of each of the first and
second bus bars spans along substantially the entire length of a
first side and a second side of the spacer, respectively. The first
and second sides of the spacer are opposite and parallel to each
other. The first leg extends to a vertex of the respective bus bar.
The vertex is between the transparent substrate and the spacer. The
second leg of each bus bar extends from the vertex between the
transparent substrate and the spacer and along a third side and a
fourth side of the spacer, respectively. The third and fourth sides
of the spacer are between the first and second sides of the spacer
and opposite and parallel to each other. The second leg of each bus
bar includes a portion that emanates from between the transparent
substrate and the spacer to outside the spacer's outer perimeter on
the third and fourth sides of the spacer, respectively. This
portion extends to a first area and a second area of the
transparent substrate, respectively, on and proximate a first
corner and a second corner of the transparent substrate. The first
and second corners are diagonally opposed to each other. The
transparent substrate and the spacer are rectangular. In one
embodiment, the electrochromic device coating (e.g., an all solid
state and inorganic electrochromic device coating) is a monolithic
device whose perimeter edges lie between the spacer and the
transparent substrate. In one embodiment, at least one of the first
and second areas is between about 1 square inch and about 10 square
inches, in another embodiment, at least one of the first and second
areas is between about 2 square inches and about 5 square inches,
and in another embodiment, at least one of the first and second
areas is between about 2 square inches and about 3 square
inches.
[0122] In some of these embodiments with electrochromic IGUs, the
first and second bus bars are adhesive bus bars. In one embodiment,
each adhesive bus bar includes an electrically conductive adhesive
with a metal foil backing. In another embodiment, the vertex is
fabricated by adhering two adhesive bus bar portion ends with or
without pressure and/or heat. In one embodiment, the vertex is
fabricated by at least one of bending, folding, soldering, welding
and brazing. For example, the two adhesive bus bar portion ends may
be soldered together.
[0123] FIG. 13 depicts an adhesive bus bar configuration, 1300, for
an electrochromic insulated glass unit. A glass substrate, 805, has
a spacer, 720, and adhesive bus bars, 370. Adhesive bus bars 370
are along their length arranged under the spacer. In this example,
each of two bus bars has only one vertex and are symmetrical. In
this example, each bus bar has a first leg that follows the length
of the spacer and is registered with the spacer, but on opposing
sides of the spacer. The first leg spans to a first vertex, 810,
and continues on to emanate from between the spacer and the glass
substrate to provide a tab for making an electrical connection such
as soldering a wire. A second leg spans from the vertex to along an
orthogonal side and does not emanate from under the spacer. Each of
the first and second bus bars emanate to a first and a second area,
respectively, to make electrical connections. The first and second
areas are diagonally opposed, proximate distinct corners of the
transparent substrate. This configuration has the advantage that
minimal bus bar area is used to emanate from under the spacer, only
at two places, to make electrical connections, for example wire
attachment, for example soldering of leads. In this example, the
first leg and second legs of the bus bar are used to power an
electrochromic device where the entire perimeter edge of the
electrochromic device is also between the spacer and the
substrate.
[0124] Certain electrochromic insulated glass units or
electrochromic IGUs include a transparent substrate with an
electrochromic device coating thereon, a spacer sandwiched between
the transparent substrate and another substrate, and a first bus
bar, and a second bus bar. Each of the bus bars includes a first
leg, a second leg, and a vertex. The first leg spans along
substantially the entire length of a first side and a second side
of the spacer, respectively. The first and second sides of the
spacer are opposite and parallel to each other. The first leg
includes a portion emanating from between the transparent substrate
and the spacer to outside the spacer's outer perimeter on a third
and fourth side of the spacer, respectively. The third and fourth
sides are between the first and second sides of the spacer and
opposite and parallel to each other. This portion of the first leg
extends to a first area and a second area of the transparent
substrate, respectively. The first area is proximate a first corner
and the second area is proximate a second corner diagonally opposed
to the first corner. The second leg of each of the bus bars is
between the transparent substrate and the spacer and along the
third and fourth sides of the spacer, respectively. The vertex is
between the transparent substrate and the spacer. The vertex is
formed by an intersection of the first leg and the second leg. The
transparent substrate and the spacer are rectangular. In one
embodiment, the electrochromic device coating (e.g., an all solid
state and inorganic electrochromic device coating) is a monolithic
device whose perimeter edges lie between the spacer and the
transparent substrate. In some of these embodiments with
electrochromic IGUs, the first and second bus bars are adhesive bus
bars. In one embodiment, each adhesive bus bar includes an
electrically conductive adhesive with a metal foil backing. In
another embodiment, the vertex is fabricated by adhering two
adhesive bus bar portion ends with or without pressure and/or heat.
In one embodiment, the two adhesive bus bar portion ends are
fabricated by at least one of soldering, welding and brazing. For
example, the vertex may be fabricated by soldering.
[0125] FIG. 14 depicts an adhesive bus bar configuration, 1400, for
an electrochromic insulated glass unit. A glass substrate, 805, has
a spacer, 720, and adhesive bus bars, 370. Adhesive bus bars 370
are along their length arranged under the spacer. In this example,
each of two bus bars has only one vertex and are symmetrical. In
this example, each bus bar has a first leg that follows the length
of the spacer and is registered with the spacer, but on opposing
sides of the spacer. The first leg spans to a first vertex, 810,
and continues on but does not emanate from under the spacer. Each
of the first and second bus bars emanate to a first and a second
area, respectively, to make electrical connections. Vertex 810 is
formed from the intersection of the first leg with a second leg,
which does emanate from between the spacer and the transparent
substrate. Each of the second legs ends at a first and a second
area. The first and second areas are on opposite sides of and
outside the outer perimeter of the spacer. In this example, they
are proximate the center of the first leg, but could be anywhere
along the first leg, independent of each other (i.e. the two bus
bars are not symmetrical). When the vertex is approximately at the
center, current distribution is more even. This configuration has
the advantage that minimal bus bar area is used to emanate from
under the spacer, only at two places, to make electrical
connections, for example wire attachment, for example soldering of
leads. In this example, the first leg of the bus bars is used to
power an electrochromic device where the entire perimeter edge of
the electrochromic device is also between the spacer and the
substrate. FIG. 15 shows that similar configurations are
envisioned, where each of the four sides has such a bus bar. In
this example, all four of the bus bars are used to power the
electrochromic device. In one embodiment, both of the opposing bus
bar pairs are configured on opposing transparent conductive layers
of an electrochromic device. In one embodiment, one of the opposing
bus bar pairs is configured on one transparent conductive layer of
an electrochromic device, and the other of the opposing bus bar
pairs is configured on the other transparent conductive layer of
the electrochromic device.
[0126] Certain electrochromic insulated glass units or
electrochromic IGUs include a transparent substrate with an
electrochromic device coating thereon, a spacer sandwiched between
the transparent substrate and another substrate, a first bus bar,
and a second bus bar. Each of the bus bars includes a first leg, a
second leg, and a vertex. The first leg is between the transparent
substrate and the spacer. The first leg spans along substantially
the entire length of a first side and a second side of the spacer,
respectively. The first and second sides of the spacer are opposite
and parallel to each other. The second leg includes a portion that
emanates from between the transparent substrate and the spacer on
the first and second sides of the spacer, respectively. The portion
extends to a first area and a second area, respectively, of the
transparent substrate outside the spacer's outer perimeter. The
vertex is between the transparent substrate and the spacer. The
vertex is formed by intersection of the first leg and the second
leg. The transparent substrate and the spacer are rectangular. In
one embodiment, the electrochromic device coating (e.g., an all
solid state and inorganic electrochromic device coating) is a
monolithic device whose perimeter edges lie between the spacer and
the transparent substrate. In some of these embodiments with
electrochromic IGUs, the first and second bus bars are adhesive bus
bars. In one embodiment, each adhesive bus bar includes an
electrically conductive adhesive with a metal foil backing. In
another embodiment, the vertex is fabricated by adhering two
adhesive bus bar portion ends with or without pressure and/or heat.
In one embodiment, the vertex is fabricated by at least one of
soldering, welding and brazing. For example, the vertex may be
fabricated by soldering. In one embodiment, the vertex is proximate
the middle of the first leg.
[0127] In one embodiment of the electrochromic IGU, the
electrochromic IGU further includes a third and a fourth bus bar,
having the same configuration as the first and second bus bars. The
first leg of each of the third and fourth bus bars is between the
spacer and the transparent substrate on a third side and a fourth
side of the spacer, respectively. The third and fourth sides of the
spacer are between the first and second sides of the spacer and on
opposing sides of the spacer.
[0128] FIG. 16 depicts an adhesive bus bar configuration, 1600, for
an electrochromic insulated glass unit. A glass substrate, 805, has
a spacer, 720, and adhesive bus bars, 370. Adhesive bus bars 370
are along their length arranged under the spacer, and each has an
end that emanates from between the spacer and the transparent
substrate in order to make electrical connections, for example wire
attachment, for example soldering of leads, in this example the bus
bar tabs are located on diagonally opposed corners of the
transparent substrate. FIG. 17 depicts an adhesive bus bar
configuration, 1700, for an electrochromic insulated glass unit. A
glass substrate, 805, has a spacer, 720, and adhesive bus bars,
370. Adhesive bus bars 370 are along their length arranged under
the spacer, and each has an end that emanates from between the
spacer and the transparent substrate in order to make electrical
connections, for example wire attachment, for example soldering of
leads, in this example the bus bar tabs are located on adjacent
corners of the transparent substrate. FIG. 18 depicts an adhesive
bus bar configuration, 1800, for an electrochromic insulated glass
unit. A glass substrate, 805, has a spacer, 720, and adhesive bus
bars, 370. Adhesive bus bars 370 are along their length arranged
under the spacer, and each is a linear span having both ends
emanating from between the spacer and the transparent substrate in
order to make electrical connections, for example wire attachment,
for example soldering of leads. This configuration has the
advantage of attaching wire leads to both ends of each bus bar for
more efficient powering and uniform current flow across the length
of the bus bars. FIG. 19 depicts an adhesive bus bar configuration,
1900, for an electrochromic insulated glass unit. A glass
substrate, 805, has a spacer, 720, and adhesive bus bars, 370.
Adhesive bus bars 370 are along their length arranged under the
spacer, and each is a linear span having one end emanating from
between the spacer and the transparent substrate in order to make
electrical connections, for example wire attachment, for example
soldering of leads. This configuration has the advantage of having
power supplied to all four sides of the electrochromic device, and
like other embodiments utilizing a single linear span for a bus
bar, fabrication is simplified.
[0129] Certain electrochromic insulated glass units or
electrochromic IGUs include a transparent substrate with an
electrochromic device coating thereon, a spacer sandwiched between
the transparent substrate and another substrate, and a first bus
bar, and a second bus bar. Each of the first and second bus bars
includes a linear span between the transparent substrate and the
spacer along substantially the entire length of a first side and a
second side of the spacer, respectively. The first and second sides
of the spacer are opposite and parallel to each other. At least one
end of the linear span emanates from between the transparent
substrate and the spacer. The linear span of the bus bars extends
to a first area and a second area, respectively, on the transparent
substrate outside the spacer's outer perimeter. The transparent
substrate and the spacer are rectangular. In one embodiment, the
electrochromic device coating (e.g., an all solid state and
inorganic electrochromic device coating) is a monolithic device
whose perimeter edges lie between the spacer and the transparent
substrate. In some of these embodiments with electrochromic IGUs,
the first and second bus bars are adhesive bus bars. In one
embodiment, each adhesive bus bar includes an electrically
conductive adhesive with a metal foil backing. In one embodiment,
the first area and the second area are proximate diagonally opposed
corners of the transparent substrate. In another embodiment, the
first area and the second area are proximate adjacent corners of
the transparent substrate. In another embodiment, both ends of the
linear span emanate from between the transparent substrate and the
spacer and extend outside the spacer's outer perimeter, terminating
at the first area, the second area, a third area and a fourth area,
where each of the first, second, third and fourth areas is
proximate a distinct corner of the transparent substrate.
[0130] In one of these embodiments with an electrochromic IGU, the
electrochromic IGU also includes a third bus bar and a fourth bus
bar. The third and fourth bus bars have the same configuration as
the first and second bus bars. The linear span of each of the third
and fourth bus bars is between the spacer and the transparent
substrate on a third and a fourth side of the spacer, respectively.
The third and fourth sides of the spacer are between the first and
second sides of the spacer and on opposing sides of the spacer.
Each of the third and fourth bus bar's linear span emanates from
between the transparent substrate and the spacer, to a third area
and a fourth area, respectively, on the transparent substrate
outside the spacer's outer perimeter. Each of the first, second,
third and fourth areas is proximate a distinct corner and a
distinct side of the transparent substrate.
[0131] FIG. 21 depicts an adhesive bus bar configuration, 2100, for
an electrochromic insulated glass unit. A glass substrate, 805, has
a spacer, 720, and adhesive bus bars, 370. Adhesive bus bars 370
are along their length arranged under the spacer. In this example,
each of two bus bars has two vertices. In this example, each bus
bar has a first leg that follows the length of the spacer and is
registered with the spacer, but on opposing sides of the spacer.
The first leg spans to a first vertex, 810a, and continues on a
second leg, also between the spacer and the transparent substrate.
A third leg is attached to the second leg, and emanates from
between the spacer and the glass substrate to provide a tab for
making an electrical connection such as soldering a wire. The end
of the third leg intersects the second leg at a second vertex,
810b. In this embodiment, the location of the second vertex is
configured such that there is approximately equal length of bus bar
on either side of the vertex. This configuration has the advantage
that minimal bus bar area is used to emanate from under the spacer,
only at two places, to make electrical connections, for example
wire attachment, for example soldering of leads. Also, current
distribution is more even with placement of the second vertex. In
this example, the first and second leg of the bus bars is used to
power an electrochromic device where the entire perimeter edge of
the electrochromic device is also between the spacer and the
substrate.
[0132] Certain electrochromic insulated glass units or
electrochromic IGUs include a transparent substrate with an
electrochromic device coating thereon, a spacer sandwiched between
the transparent substrate and another substrate, and a first bus
bar, and a second bus bar. Each of the first and second bus bars
includes a first leg, a second leg, and third leg. The first leg is
between the transparent substrate and the spacer. The first leg
spans along substantially the entire length of a first side and a
second side of the spacer, respectively. The first and second sides
of the spacer are opposite and parallel to each other. The first
leg extends to a first vertex between the transparent substrate and
the spacer. The second leg is between the transparent substrate and
the spacer. The second leg extends from the first vertex and along
a third side and a fourth side of the spacer, respectively. The
third and fourth sides of the spacer are between the first and
second sides of the spacer, respectively. The third and fourth
sides are also opposite and parallel to each other. The third leg
emanates from between the transparent substrate and spacer, on the
first and second sides of the spacer, respectively. The third leg
extends to a first and a second area, respectively, on the
transparent substrate outside the spacer's outer perimeter. A
second vertex between the transparent substrate and the spacer is
formed by an intersection of the third leg with the first leg and
the second leg, respectively. The third leg is configured such that
there is approximately equal length of bus bar on either side of
the second vertex. The transparent substrate and the spacer are
rectangular. In one embodiment, the electrochromic device coating
(e.g., an all solid state and inorganic electrochromic device
coating) is a monolithic device whose perimeter edges lie between
the spacer and the transparent substrate.
[0133] In some of these embodiments with electrochromic IGUs, the
first and second bus bars are adhesive bus bars. In one embodiment,
each adhesive bus bar includes an electrically conductive adhesive
with a metal foil backing. In one embodiment, the first and second
vertexes are fabricated by adhering two adhesive bus bar portion
ends with or without pressure and/or heat. In one embodiment, the
first and second vertexes are fabricated by at least one bending,
folding, soldering, welding and brazing. For example, the two
adhesive bus bar portion ends may be soldered together.
[0134] Although the foregoing disclosed 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.
[0135] One or more features from any embodiment may be combined
with one or more features of any other embodiment without departing
from the scope of the disclosure. Further, modifications,
additions, or omissions may be made to any embodiment without
departing from the scope of the disclosure. The components of any
embodiment may be integrated or separated according to particular
needs without departing from the scope of the disclosure.
* * * * *