U.S. patent application number 16/513973 was filed with the patent office on 2019-11-07 for coated article with low-e coating having low visible transmission which may be used in ig window unit for grey appearance.
The applicant listed for this patent is Guardian Europe S.A.R.L.. Invention is credited to Marcus FRANK, Hartmut KNOLL.
Application Number | 20190338582 16/513973 |
Document ID | / |
Family ID | 52468553 |
Filed Date | 2019-11-07 |
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United States Patent
Application |
20190338582 |
Kind Code |
A1 |
KNOLL; Hartmut ; et
al. |
November 7, 2019 |
COATED ARTICLE WITH LOW-E COATING HAVING LOW VISIBLE TRANSMISSION
WHICH MAY BE USED IN IG WINDOW UNIT FOR GREY APPEARANCE
Abstract
This invention relates to a coated article including a
low-emissivity low-E) coating. In certain example embodiments, the
low-E coating is provided on a substrate (e.g., glass substrate)
and includes at least first and second infrared (IR) reflecting
layers (e.g., silver based layers) that are spaced apart by contact
layers (e.g., NiCr based layers) and a dielectric layer of or
including a material such as silicon nitride. In certain example
embodiments, the coated article has a low visible transmission
(e.g., no greater than 60%, more preferably no greater than about
55%, and most preferably no greater than about 0%).
Inventors: |
KNOLL; Hartmut;
(Muldestrausee, DE) ; FRANK; Marcus; (Gelnhausen,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Guardian Europe S.A.R.L. |
Bertrange |
|
LU |
|
|
Family ID: |
52468553 |
Appl. No.: |
16/513973 |
Filed: |
July 17, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14911044 |
Feb 9, 2016 |
10378271 |
|
|
PCT/US2013/059406 |
Sep 12, 2013 |
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16513973 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C03C 17/3639 20130101;
C03C 17/366 20130101; B32B 17/10229 20130101; C09D 5/32 20130101;
C03C 17/3613 20130101; C03C 17/3636 20130101; B32B 17/10201
20130101; C03C 17/3644 20130101; Y10T 428/24967 20150115; C03C
17/3649 20130101; C03C 17/3681 20130101; E06B 3/6612 20130101; E06B
3/6715 20130101; G02B 5/285 20130101; C03C 17/3626 20130101; C03C
17/36 20130101; B32B 7/02 20130101; C03C 17/3652 20130101; G02B
5/282 20130101; B32B 17/1022 20130101; G02B 5/208 20130101 |
International
Class: |
E06B 3/67 20060101
E06B003/67; C03C 17/36 20060101 C03C017/36; E06B 3/66 20060101
E06B003/66; G02B 5/28 20060101 G02B005/28; G02B 5/20 20060101
G02B005/20; B32B 7/02 20060101 B32B007/02 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 16, 2013 |
US |
PCT/US2013/055357 |
Claims
1-34. (canceled)
35. A coated article including a coating supported by a glass
substrate, the coating comprising: first and second infrared (IR)
reflecting layers comprising silver, the first IR reflecting layer
being located closer to the glass substrate than is the second IR
reflecting layer; a first contact layer comprising NiCr located
over and directly contacting the first IR reflecting layer
comprising silver; a dielectric layer comprising silicon nitride
located over at least the first contact layer comprising NiCr; a
second contact layer comprising NiCr located over at least the
layer comprising silicon nitride; the second IR reflecting layer
comprising silver located over and directly contacting the second
contact layer comprising NiCr; a third contact layer comprising
NiCr located over and directly contacting the second IR reflecting
layer; another dielectric layer comprising silicon nitride located
over and directly contacting the third contact layer comprising
NiCr; wherein the second IR reflecting layer comprising silver is
at least twice as thick as the first IR reflecting layer comprising
silver; and wherein the coated article has a visible transmission,
measured monolithically, of no greater than 55% and a glass side
visible reflectance, measured monolithically, of no greater than
11%.
36. The coated article of claim 35, wherein the coated article has
a glass side visible reflectance, measured monolithically, of no
greater than 10%.
37. The coated article of claim 35, wherein the coated article has
a glass side visible reflectance, measured monolithically, of no
greater than 8%.
38. The coated article of claim 35, wherein the second IR
reflecting layer comprising silver is at least 40 angstroms (.ANG.)
thicker than is the first IR reflecting layer comprising
silver.
39. The coated article of claim 35, wherein the coated article has
a visible transmission, measured monolithically, of no greater than
50%.
40. The coated article of claim 35, wherein the dielectric layer
comprising silicon nitride that is located over and directly
contacting the first contact layer comprising NiCr is
amorphous.
41. The coated article of claim 35, wherein the first contact layer
comprising NiCr is substantially metallic or metallic and contains
no more than about 5% (atomic %) oxygen.
42. The coated article of claim 35, wherein said coated article has
a visible transmission of from about 25-55% measured
monolithically.
43. The coated article of claim 35, wherein the coating further
comprises a dielectric layer comprising silicon nitride located on
and directly contacting the glass substrate.
44. An IG window unit including the coated article of claim 35, and
another glass substrate which is coupled to said coated
article.
45. An insulating glass (IG) window unit comprising: a coated
article including a coating supported by a first glass substrate;
the first glass substrate with the coating thereon being coupled to
a second glass substrate with a gap therebetween, and wherein the
first glass substrate is adapted to be at an exterior/outside side
of the IG window unit and the second glass substrate is adapted to
be at an interior/inside side of the IG window unit adjacent an
interior of a building on which the IG window unit is mounted or is
to be mounted, and wherein the coating is on a major surface of the
first glass substrate facing the gap between the substrates;
wherein the coating supported by the first glass substrate
comprises: first and second infrared (IR) reflecting layers
comprising silver, the first IR reflecting layer being located
closer to the glass substrate than is the second IR reflecting
layer; a first contact layer comprising NiCr located over and
directly contacting the first IR reflecting layer comprising
silver; a dielectric layer comprising silicon nitride located over
at least the first contact layer comprising NiCr; a second contact
layer located over at least the layer comprising silicon nitride;
the second IR reflecting layer comprising silver located over and
directly contacting the second contact layer; a third contact layer
comprising NiCr located over and directly contacting the second IR
reflecting layer; another dielectric layer comprising silicon
nitride located over and directly contacting the third contact
layer comprising NiCr; wherein the second IR reflecting layer
comprising silver is at least 30 angstroms thicker than is the
first IR reflecting layer comprising silver; wherein the IG window
unit has a visible transmission of no greater than 50% and an
outside visible reflectance of no greater than 12%; and wherein the
IG window unit is grey or dark grey in appearance as viewed from
the outside, and wherein the first and second glass substrates of
the IG window unit are clear, not grey, glass substrates.
Description
[0001] This invention relates to a coated article including a
low-emissivity (low-E) coating for allowing a coated glass article
to have desirable grey glass side reflective coloration without
necessarily having to have a grey glass substrate. In certain
example embodiments, the low-E coating is provided on a substrate
(e.g., glass substrate) and includes at least first and second
infrared (IR) reflecting layers (e.g., silver based layers) that
are spaced apart by contact layers (e.g., NiCr based layers) and a
dielectric layer of or including a material such as silicon
nitride. In certain example embodiments, the coated article
(monolithic form and/or in IG window unit form) has a low visible
transmission (e.g., no greater than 55%, more preferably no greater
than about 50%, more preferably no greater than about 45%, and most
preferably no greater than about 40%). In certain example
embodiments, the coated article may be heat treated (e.g.,
thermally tempered and/or heat bent), and is designed to be
substantially thermally stable upon heat treatment (HT) in that its
.DELTA.E* value (glass side reflective) due to HT is no greater
than 5.0, and more preferably no greater than 4.5, and most
preferably no greater than 4.1. Coated articles according to
certain example embodiments of this invention may be used in the
context of insulating glass (IG) window units, vehicle windows, or
other types of windows.
BACKGROUND OF THE INVENTION
[0002] Coated articles are known in the art for use in window
applications such as insulating glass (IG) window units, vehicle
windows, and/or the like. It is known that in certain instances, it
is desirable to heat treat (e.g., thermally temper, heat bend
and/or heat strengthen) such coated articles for purposes of
tempering, bending, or the like. Heat treatment (HT) of coated
articles typically requires use of temperature(s) of at least 580
degrees C., more preferably of at least about 600 degrees C. and
still more preferably of at least 620 degrees C. Such high
temperatures (e.g., for 5-10 minutes or more) often cause coatings
to break down and/or deteriorate or change in an unpredictable
manner. Thus, it is desirable for coatings to be able to withstand
such heat treatments (e.g., thermal tempering), if desired, in a
predictable manner that does not significantly damage the
coating.
[0003] In certain situations, designers of coated articles strive
for a combination of desirable visible transmission, desirable
color, low emissivity (or emittance), and low sheet resistance
(R.sub.5). Low-emissivity (low-E) and low sheet resistance
characteristics permit such coated articles to block significant
amounts of IR radiation so as to reduce for example undesirable
heating of vehicle or building interiors.
[0004] U.S. Pat. No. 7,521,096, incorporated herein by reference,
discloses a low-E coating which uses zinc oxide (ZnO) contact
layers below the silver-based IR reflecting layers, and above the
bottom silver (Ag) based IR reflecting layer uses a NiCrO.sub.x
contact layer followed by a center tin oxide (SnO.sub.2) dielectric
layer. While the ZnO contact layers below the silver IR reflecting
layers provide good structural properties for the growth of silver,
the ZnO has been found to degrade the chemical, environmental and
mechanical durability of the coating in certain instances.
[0005] U.S. Pat. No. 5,557,462 discloses a low-E coating with a
layer stack of SiN/NiCr/Ag/NiCr/SiN/NiCr/AgNiCr/SiN. However, the
coated article of the '462 patent is designed for a high visible
transmission of at least 63%. The '462 patent at column 3, lines
12-15, teaches that visible transmission below 70% (monolithic
coated article) and below 63% (IG window unit) are undesirable.
Thus, the '462 patent teaches directly away from coated articles
with visible transmission lower than 63%. Moreover, as largely
explained in U.S. Pat. No. 8,173,263, coated articles of the '462
patent are not heat treatable because upon heat treatment sheet
resistance (R.sub.s) goes way up such as from about 3-5 to well
over 10, haze tends to set in, and the glass side reflective
.DELTA.E* value is undesirable because it is over 5.0.
[0006] Accordingly, it would be desirable to provided a coated
article that is characterized by one, two, three or all four of:
(i) low visible transmission, (ii) good durability, (iii) desirable
coloration, and/or (iv) thermal stability upon HT so as to realize
a glass side reflective .DELTA.E* value no greater than about 5.0,
more preferably no greater than about 4.5. Moreover, it may also be
desirable for IG window units which include such coated articles to
have low solar factor (SF), and/or low outside reflectance such as
no greater than about 12%, more preferably no greater than about
11%, still more preferably no greater than about 10%, and most
preferably no greater than about 9%. See EN 410 regarding
calculation of SF and visible transmission of an IG unit.
[0007] The term .DELTA.E* (and .DELTA.E) is well understood in the
art and is reported, along with various techniques for determining
it, in ASTM 2244-93 as well as being reported in Hunter et. al.,
The Measurement of Appearance, 2.sup.nd Ed. Cptr. 9, page 162 et
seq. [John Wiley & Sons, 1987]. As used in the art, .DELTA.E*
(and .DELTA.E) is a way of adequately expressing the change (or
lack thereof) in reflectance and/or transmittance (and thus color
appearance, as well) in an article after or due to heat treatment.
.DELTA.E may be calculated by the "ab" technique, or by the Hunter
technique (designated by employing a subscript "H"). .DELTA.E
corresponds to the Hunter Lab L, a, b scale (or L.sub.h, a.sub.h,
b.sub.h). Similarly, .DELTA.E* corresponds to the CIE LAB Scale L*,
a*, b*. Both are deemed useful, and equivalent for the purposes of
this invention. For example, as reported in Hunter et. al.
referenced above, the rectangular coordinate/scale technique (CIE
LAB 1976) known as the L*, a*, b* scale may be used, wherein: L* is
(CIE 1976) lightness units; a* is (CIE 1976) red-green units; b* is
(CIE 1976) yellow-blue units; and the distance .DELTA.E* between
L*.sub.o a*.sub.o b*.sub.o and L*.sub.1 a*.sub.1b*.sub.1 is:
.DELTA.E*=[(.DELTA.L*).sup.2+(.DELTA.b*).sup.2].sup.1/2, where
.DELTA.L*=L*.sub.1-L*.sub.c; .DELTA.a*=a*.sub.1-a*.sub.o;
.DELTA.b*=b*.sub.1-b*; where the subscript "o" represents the
coating (coated article) before heat treatment and the subscript
"1" represents the coating (coated article) after heat treatment;
and the numbers employed (e.g., a*, b*, L*) are those calculated by
the aforesaid (CIE LAB 1976) L*, a*, b* coordinate technique. When,
for example, glass side reflective .DELTA.E* values are measured,
then glass side reflective a*, b* and L* values are used. In a
similar manner, .DELTA.E may be calculated using the above equation
for .DELTA.E*, i.e., .DELTA.E*
[(.DELTA.L*).sup.2+(.DELTA.a*).sup.2+(.DELTA.b*).sup.2].sup.1/2, by
replacing a*, b*, L* with Hunter Lab values a.sub.h, b.sub.h,
L.sub.h. Also within the scope of this invention and the
quantification of .DELTA.E* are the equivalent numbers if converted
to those calculated by any other technique employing the same
concept of .DELTA.E* as defined above.
[0008] U-value (sometimes referred to as U-factor) is a measure of
heat loss in a building element such as a wall, floor, window or
roof. It can also be referred to as an overall heat transfer
co-efficient and measures how well parts of a building transfer
heat. This means that the higher the U-value the worse the thermal
performance of the building envelope. A low U-value usually
indicates high levels of insulation. In other words, U-value
measures how well a product prevents heat from escaping a home or
building. The lower the U-value, the better a product is at keeping
heat inside the building. U-value herein is measured in units of
W/m.sup.2K) unless otherwise stated. See EN 673 regarding
calculation of U-value.
BRIEF SUMMARY OF EXAMPLE EMBODIMENTS OF THE INVENTION
[0009] This invention relates to a coated article including a
low-emissivity (low-E) coating for allowing a coated glass article
to have desirable grey glass side reflective coloration without
necessarily having to have a grey glass substrate. In certain
example embodiments, the low-E coating is provided on a substrate
(e.g., glass substrate) and includes at least first and second
infrared (IR) reflecting layers (e.g., silver based layers) that
are spaced apart by contact layers (e.g., NiCr based layers) and a
dielectric layer of or including a material such as silicon
nitride. In certain example embodiments, the coated article has a
low visible transmission (e.g., no greater than 55%, more
preferably no greater than about 50%, more preferably no greater
than about 45%, and most preferably no greater than about 40%,
measured monolithically and/or in an IG unit). In certain example
embodiments, the coated article may be heat treated (e.g.,
thermally tempered and/or heat bent), and is designed to be
substantially thermally stable upon heat treatment (HT) in that its
.DELTA.E* value (glass side reflective) measured monolithically due
to HT is no greater than 5.0, more preferably no greater than 4.5,
and still more preferably of no greater than 4.1. Such a low
.DELTA.E* value indicates that the coated article has approximately
the same transmission and color characteristics as viewed by the
naked eye both before and after heat treatment (e.g., thermal
tempering). Coated articles according to certain example
embodiments of this invention may be used in the context of
insulating glass (IG) window units, vehicle windows, or other types
of windows.
[0010] It is desired to provide a coated article that is
characterized by one, two, three, or all four of: (i) low visible
transmission, (ii) good durability, (iii) desirable grey glass side
coloration, and (iv) thermal stability upon HT so as to realize a
glass side reflective .DELTA.E* value no greater than 5.0, more
preferably no greater than 4.5. Moreover, it is desirable for IG
window units which include such coated articles to have one, two,
or all three of: (a) low solar factor (SF) such as no greater than
about 33%, more preferably no greater than about 31%, still more
preferably no greater than about 29%, and even more preferably no
greater than about 27%, (b) low outside reflectance such as no
greater than about 12%, more preferably no greater than about 11%,
still more preferably no greater than about 10%, and most
preferably no greater than about 9%, and/or (e) outside reflective
grey coloration.
[0011] In certain example embodiments of this invention, there is
provided a an insulating glass (IG) window unit comprising: a
coated article including a coating supported by a first glass
substrate; the first glass substrate with the coating thereon being
coupled to a second glass substrate with a gap therebetween, and
wherein the first glass substrate is adapted to be at an
exterior/outside side of the IG window unit and the second glass
substrate is adapted to be at an interior/inside side of the IG
window unit adjacent an interior of a building on which the IG
window unit is mounted or is to be mounted, and wherein the coating
is on a major surface of the first glass substrate facing the gap
between the substrates; wherein the coating supported by the first
glass substrate comprises: first and second infrared (IR)
reflecting layers comprising silver, the first IR reflecting layer
being located closer to the glass substrate than is the second IR
reflecting layer; a first contact layer comprising NiCr located
over and directly contacting the first IR reflecting layer
comprising silver; a dielectric layer comprising silicon nitride
located over and directly contacting the first contact layer
comprising NiCr; a second contact layer located over and directly
contacting the layer comprising silicon nitride; the second IR
reflecting layer comprising silver located over and directly
contacting the second contact layer; a third contact layer
comprising NiCr located over and directly contacting the second IR
reflecting layer; another dielectric layer comprising silicon
nitride located over and directly contacting the third contact
layer comprising NiCr; wherein the second IR reflecting layer
comprising silver is at least 30 angstroms thicker than is the
first IR reflecting layer comprising silver; wherein the IG window
unit has a visible transmission of no greater than 50% and an
outside visible reflectance of no greater than 12%; and wherein the
IG window unit is grey or dark grey in appearance as viewed from
the outside, and wherein the first and second glass substrates of
the IG window unit are clear, not grey, glass substrates.
[0012] In certain example embodiments of this invention, there is
provided coated article including a coating supported by a glass
substrate, the coating comprising: first and second infrared (IR)
reflecting layers comprising silver, the first IR reflecting layer
being located closer to the glass substrate than is the second IR
reflecting layer; a first contact layer comprising NiCr located
over and directly contacting the first IR reflecting layer
comprising silver; a dielectric layer comprising silicon nitride
located over and directly contacting the first contact layer
comprising NiCr; a second contact layer comprising NiCr located
over and directly contacting the layer comprising silicon nitride;
the second IR reflecting layer comprising silver located over and
directly contacting the second contact layer comprising NiCr; a
third contact layer comprising NiCr located over and directly
contacting the second IR reflecting layer; another dielectric layer
comprising silicon nitride located over and directly contacting the
third contact layer comprising NiCr; wherein the second IR
reflecting layer comprising silver is at least twice as thick as
the first IR reflecting layer comprising silver; and wherein the
coated article has a visible transmission, measured monolithically,
of no greater than 55% and a glass side visible reflectance,
measured monolithically, of no greater than 11%.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a cross sectional view of a coated article
according to an example embodiment of this invention.
[0014] FIG. 2 is a cross sectional view showing the coated article
of FIG. 1 provided in an IG window unit according to an example
embodiment of this invention.
DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION
[0015] Coated articles herein may be used in applications such as
IG window units, laminated window units (e.g., for use in vehicle
or building applications), vehicle windows, monolithic
architectural windows, residential windows, and/or any other
suitable window application that includes single or multiple glass
substrates.
[0016] In certain example embodiments, the outside (glass side)
color of an IG window unit including a coated article will be grey
or dark grey, and the coating is capable of allowing IG window
units to realize low visible transmission, low solar factor, low
outside visible reflection, low emissivity, and low U-value. In
certain example embodiments, it is possible to achieve a very low
outside reflection in IG window units with outside reflective grey
coloration when a clear base glass is used in a coated article
which can make up the outside lite of the IG window unit. Thus, it
is not necessary to use a grey base glass for the mentioned outside
impression. Clear glass is less expensive and has a much better
availability than grey base glass. While grey glass substrates
could possibly be used in example embodiments of this invention,
preferred embodiments use clear or neutral colored glass substrates
and achieve the desired grey coloration due to the coating design
without the need for grey colored glass. While the coated articles
herein may be heat treated (e.g., thermally tempered), coated
articles according to example embodiments of this invention need
not be heat treated and may be either HT or non-HT.
[0017] In certain example embodiments of this invention, the
coating includes a double-silver stack. Referring to FIG. 1 for
example, in certain example embodiments of this invention, there is
provided a coated article including a coating 30 supported by a
glass substrate 1, the coating 30 comprising: first 9 and second 19
infrared (IR) reflecting layers comprising or consisting
essentially of silver, the first IR reflecting layer 9 being
located closer to the glass substrate 1 than is the second IR
reflecting layer 19; a first contact layer comprising NiCr 7
located under and directly contacting the first IR reflecting layer
comprising silver 9, a second contact layer 11 located over and
directly contacting the first IR reflecting layer comprising silver
9; a transparent dielectric layer of or including silicon nitride
14 located over and directly contacting the second contact layer
comprising NiCr 11; a third contact layer comprising NiCr 17
located over and directly contacting the layer comprising silicon
nitride 14; the second IR reflecting layer comprising silver 19
located over and directly contacting the third contact layer
comprising NiCr 17; a fourth contact layer comprising NiCr 21
located over and directly contacting the second IR reflecting layer
19, and wherein the second IR reflecting layer comprising silver 19
is at least as thick as the first IR reflecting layer comprising
silver 9. In certain preferred embodiments, it has been found that
surprisingly beneficial results can be achieved when the second IR
reflecting layer of or including silver 19 is thicker than the
first IR reflecting layer of or including silver 9, more preferably
when second IR reflecting layer 19 is at least 10 angstroms (.ANG.)
thicker (more preferably at least 20 angstroms thicker, even more
preferably at least 30 angstroms thicker, still more preferably at
least 40 angstroms thicker, still more preferably at least 50
angstroms thicker, and most preferably at least 65 angstroms
thicker) than the first IR reflecting layer comprising silver 9.
The coating in FIG. 1 includes three transparent dielectric layers
3, 14 and 24 of or including silicon nitride, as shown in FIG. 1.
Moreover, the coating may optionally include an overcoat layer (not
shown) of or including zirconium oxide and/or zirconium oxynitride,
where such an optional overcoat layer can be located over and
directly contacting silicon nitride based layer 24. In certain
example embodiments, this overcoat layer of or including zirconium
oxide and/or zirconium oxynitride 27 may be thinner than one or
both of the IR reflecting layers 9, 19. In certain example
embodiments of this invention, each of the IR reflecting layers
comprising silver 9 and 19 may be at least twice as thick, and more
preferably at least three times as thick, as the optional overcoat
layer of or including zirconium oxide and/or zirconium oxynitride.
In certain example embodiments of this invention, the coating 30
includes only two IR reflecting layers 9, 19 of or including silver
or the like.
[0018] In order to increase durability, along with optics and
thermal properties, and avoid significant structural changes before
and after HT, coated articles according to certain example
embodiments of this invention have a center dielectric layer 14 of
or including silicon nitride and lower contact layers 7, 17 are
based on NiCr (as opposed to ZnO). It has also been found that
using metallic or substantially metallic NiCr (possibly partly
nitrided) for layer(s) 7, 11, 17 and/or 21 improves chemical,
mechanical and environmental durability (compared to using ZnO
lower contact layers below silver and/or highly oxided NiCr upper
contact layers above silver). It has also been found that
sputter-depositing silicon nitride inclusive layer 14 in an
amorphous state, so that it is amorphous in both as-coated and HT
states, helps with overall stability of the coating. For example,
5% HCl at 65 degrees C. for one hour will remove the coating of
U.S. Pat. No. 7,521,096, whereas the coating shown in FIG. 1 and
the examples herein will survive this HCl test. And in high
temperature and high humidity environment, there is less damage to
the coating of FIG. 1 and the examples herein after ten days of
exposure, than to the coating of the '096 patent after two days of
exposure. And regarding high corrosive chemicals such as those used
for "brick wash", corrosion resistance is such that edge deletion
need not be performed in certain example IG and laminated
embodiments. Moreover, it has been found that making the top Ag
based IR reflecting layer 19 thicker than the bottom Ag based IR
reflecting layer 9 improves certain optical characteristics of the
coating. The coating can be used as-coated, or heat treated, due to
the relatively low .DELTA.E* values discussed herein. For example,
when the coating 30 is located surface #2 of an IG window unit (as
shown in FIG. 2), low glass side reflective .DELTA.E* values due to
heat treatment indicate that the coated article has approximately
the same transmission and color characteristics as viewed by the
naked eye both before and after heat treatment (e.g., thermal
tempering), and thus can be used either as-coated or as heat
treated without significantly affecting optical characteristics
thereof.
[0019] In certain example embodiments of this invention such as
FIG. 1, heat treated or non-heat-treated coated articles having
multiple IR reflecting layers (e.g., two spaced apart silver based
layers 9 and 19) are capable of realizing a sheet resistance
(R.sub.s) of less than or equal to 5.0 (more preferably less than
or equal to 4.0 ohms/square). The terms "heat treatment" and "heat
treating" as used herein mean heating the article to a temperature
sufficient to achieve thermal tempering, heat bending, and/or heat
strengthening of the glass inclusive article. This definition
includes, for example, heating a coated article in an oven or
furnace at a temperature of least about 580 degrees C., more
preferably at least about 600 degrees C., for a sufficient period
to allow tempering, bending, and/or heat strengthening. In certain
instances, the HT may be for at least about 4 or 5 minutes. The
coated article may or may not be heat treated in different
embodiments of this invention.
[0020] FIG. 1 is a side cross sectional view of a coated article
according to an example non-limiting embodiment of this invention.
The coated article includes substrate 1 (e.g., clear, green,
bronze, grey, or blue-green glass substrate from about 1.0 to 12.0
mm thick, more preferably from about 4 mm to 8 mm thick), and low-E
coating (or layer system) 30 provided on the substrate 1 either
directly or indirectly. The coating (or layer system) 30 includes,
for example: bottom dielectric silicon nitride layer 3 which may be
Si.sub.3N.sub.4, or of the Si-rich type silicon nitride for haze
reduction, or of any other suitable stoichiometry silicon nitride
in different embodiments of this invention, lower contact layer 7
(which contacts bottom IR reflecting layer 9), first conductive and
preferably metallic or substantially metallic infrared (IR)
reflecting layer 9, upper contact layer 11 (which contacts layer
9), dielectric silicon nitride based and/or inclusive layer 14,
lower contact layer 17 (which contacts IR reflecting layer 19),
second conductive and preferably metallic or substantially metallic
IR reflecting layer 19, upper contact layer 21 (which contacts
layer 19), and transparent dielectric silicon nitride layer 24
which may be Si.sub.3N.sub.4, of the Si-rich type for haze
reduction, or of any other suitable stoichiometry silicon nitride
in different embodiments of this invention. The "contact" layers 7,
11, 17 and 21 each contact an IR reflecting layer (e.g., layer
based on Ag). The aforesaid layers 3-24 make up low-E (i.e., low
emissivity) coating 30 that is provided on glass substrate 1.
Layers 3-24 may be sputter-deposited on the substrate 1 in certain
example embodiments of this invention, with each layer being
sputter-deposited in vacuum using one or more targets as needed
(the sputtering targets may be ceramic or metallic). Metallic or
substantially metallic layers (e.g., layers 7, 9, 11, 17, 19 and
21) may be sputtered in an atmosphere containing argon gas, whereas
nitrided layers (e.g., layers 3, 7, 11, 14, 17, 21 and 24) may be
sputtered in an atmosphere containing a mixture of nitrogen and
argon gas. The contact layers 7, 11, 17 and 21 may or may not be
nitrided in different example embodiments of this invention.
[0021] In monolithic instances, the coated article includes only
one glass substrate 1 as illustrated in FIG. 1. However, monolithic
coated articles herein may be used in devices such as laminated
vehicle windshields, IG window units, and the like. As for IG
window units, an IG window unit may include two spaced apart glass
substrates. An example IG window unit is illustrated and described,
for example, in U.S. Patent Document No. 2004/0005467, the
disclosure of which is hereby incorporated herein by reference.
FIG. 2 shows an example IG window unit including the coated glass
substrate 1 shown in FIG. 1 coupled to another glass substrate 2
via spacer(s), sealant(s) 40 or the like, with a gap 50 being
defined therebetween. This gap 50 between the substrates in IG
window unit embodiments may in certain instances be filled with a
gas such as argon (Ar). An example IG unit may comprise a pair of
spaced apart clear glass substrates 1 and 2 each about 3-4 mm
thick, one of which is coated with a coating 30 herein in certain
example instances, where the gap 50 between the substrates may be
from about 5 to 30 mm, more preferably from about 10 to 20 mm, and
most preferably about 16 mm. In certain example instances, the
low-E coating 30 may be provided on the interior surface of either
substrate facing the gap (the coating is shown on the interior
major surface of substrate 1 in FIG. 2 facing the gap 50, but
instead could be on the interior major surface of substrate 2
facing the gap 50). Either substrate 1 or substrate 2 may be the
outermost substrate of the IG window unit at the building exterior
(e.g., in FIG. 2 the substrate 1 is the substrate closest to the
building exterior, and the coating 30 is provided on surface #2 of
the IG window unit). In preferred embodiments of this invention,
the coating 30 is provided on surface #2 of the IG window unit as
shown in FIG. 2.
[0022] In certain example embodiments of this invention, one, two,
three, or all four of contact layers 7, 11, 17, 21 may be of or
include NiCr (any suitable ratio of Ni:Cr), and may or may not be
nitrided (NiCrN.sub.x). In certain example embodiments, one, two,
three or all four of these NiCr inclusive layers 7, 11, 17, 21
is/are substantially or entirely non-oxidized. In certain example
embodiments, layers 7, 11, 17 and 21 may all be of metallic NiCr or
substantially metallic NiCr (although trace amounts of other
elements may be present). In certain example embodiments, one, two,
three or all four of NiCr based layers 7, 11, 17, 21 may comprise
from 0-10% oxygen, more preferably from 0-5% oxygen, and most
preferably from 0-2% oxygen (atomic %). In certain example
embodiments, one, two, three or all four of these layers 7, 11, 17,
21 may contain from 0-20% nitrogen, more preferably from 1-15%
nitrogen, and most preferably from about 1-12% nitrogen (atomic %).
NiCr based layers 7, 11, 17 and/or 21 may or may not be doped with
other material(s) such as stainless steel, Mo, or the like. It has
been found that the use of NiCr based contact layer(s) 7 and/or 17
under the silver-based IR reflecting layer(s) 9, 19 improves
durability of the coated article (compared to if layers 7 and 17
were instead of ZnO). Moreover, it was surprisingly found that
making layers 7, 11, 17 and 21 of or consisting essentially of NiCr
provided for improved durability, as introduction of more than
trace amounts of oxygen resulted in undesirable haze and reduced
durability compared to if the layers 7, 11, 17 and 21 consist
essentially of NiCr.
[0023] Dielectric layers 3, 14, and 24 may be of or include silicon
nitride in certain embodiments of this invention. Silicon nitride
layers 3, 14 and 24 may, among other things, improve
heat-treatability of the coated articles and protect the other
layers during optional HT, e.g., such as thermal tempering or the
like. One or more of the silicon nitride of layers 3, 14, 24 may be
of the stoichiometric type (i.e., Si.sub.3N.sub.4), or
alternatively of the Si-rich type of silicon nitride in different
embodiments of this invention. The presence of free Si in a Si-rich
silicon nitride inclusive layer 3 and/or 14 may, for example, allow
certain atoms such as sodium (Na) which migrate outwardly from the
glass 1 during HT to be more efficiently stopped by the Si-rich
silicon nitride inclusive layer(s) before they can reach silver and
damage the same. Thus, it is believed that the Si-rich
Si.sub.xN.sub.y can reduce the amount of damage done to the silver
layer(s) during HT in certain example embodiments of this invention
thereby allowing sheet resistance (R.sub.s) to decrease or remain
about the same in a satisfactory manner. Moreover, it is believed
that the Si-rich Si.sub.xN.sub.y in layers 3, 14 and/or 24 can
reduce the amount of damage (e.g., oxidation) done to the silver
and/or NiCr during HT in certain example optional embodiments of
this invention. In certain example embodiments, when Si-rich
silicon nitride is used, the Si-rich silicon nitride layer (3, 14
and/or 24) as deposited may be characterized by Si.sub.xN.sub.y
layer(s), where x/y may be from 0.76 to 1.5, more preferably from
0.8 to 1.4, still more preferably from 0.82 to 1.2. Any and/or all
of the silicon nitride layers discussed herein may be doped with
other materials such as stainless steel or aluminum in certain
example embodiments of this invention. For example, any and/or all
silicon nitride layers 3, 14, 24 discussed herein may optionally
include from about 0-15% aluminum, more preferably from about 1 to
10% aluminum, in certain example embodiments of this invention. The
silicon nitride of layers 3, 14, 24 may be deposited by sputtering
a target of Si or SiAl, in an atmosphere having argon and nitrogen
gas, in certain embodiments of this invention. Small amounts of
oxygen may also be provided in certain instances in the silicon
nitride layers.
[0024] Infrared (IR) reflecting layers 9 and 19 are preferably
substantially or entirely metallic and/or conductive, and may
comprise or consist essentially of silver (Ag), gold, or any other
suitable IR reflecting material. IR reflecting layers 9 and 19 help
allow the coating to have low-F, and/or good solar control
characteristics.
[0025] Other layer(s) below or above the illustrated coating may
also be provided. Thus, while the layer system or coating is "on"
or "supported by" substrate 1 (directly or indirectly), other
layer(s) may be provided therebetween. Thus, for example, the
coating of FIG. 1 may be considered "on" and "supported by" the
substrate 1 even if other layer(s) are provided between layer 3 and
substrate 1. Moreover, certain layers of the illustrated coating
may be removed in certain embodiments, while others may be added
between the various layers or the various layer(s) may be split
with other layer(s) added between the split sections in other
embodiments of this invention without departing from the overall
spirit of certain embodiments of this invention. As another
example, a zirconium oxide overcoat layer may be provided in
coating 30.
[0026] While various thicknesses and materials may be used in
layers in different embodiments of this invention, example
thicknesses and materials for the respective layers on the glass
substrate 1 in the FIG. 1 embodiment are as follows, from the glass
substrate outwardly (physical thicknesses recited):
TABLE-US-00001 Example Materials/Thicknesses; FIG. 1 Embodiment
Layer Preferred More Glass (1-10 mm thick) Range ({acute over
(.ANG.)}) Preferred ({acute over (.ANG.)}) Example (.ANG.)
Si.sub.xN.sub.y (layer 3) 100-500 .ANG. 250-450 .ANG. 380 .ANG.
NiCr or NiCrN (layer 7) 10-30 {acute over (.ANG.)} 11-20 {acute
over (.ANG.)} 15 .ANG. Ag (layer 9) 30-150 {acute over (.ANG.)}
30-70 {acute over (.ANG.)} 50 .ANG. NiCr or NiCrN (layer 11) 10-30
{acute over (.ANG.)} 11-20 {acute over (.ANG.)} 15 .ANG.
Si.sub.xN.sub.y (layer 14) 300-1400 {acute over (.ANG.)} 650-1100
{acute over (.ANG.)} 740 .ANG. NiCr or NiCrN (layer 17) 7-30 {acute
over (.ANG.)} 9-20 {acute over (.ANG.)} 10 .ANG. Ag (layer 19)
80-225 {acute over (.ANG.)} 110-180 {acute over (.ANG.)} 130 .ANG.
NiCr or NiCrN (layer 21) 8-30 {acute over (.ANG.)} 9-20 {acute over
(.ANG.)} 10 .ANG. Si.sub.3N.sub.4 (layer 24) 120-360 {acute over
(.ANG.)} 250-340 {acute over (.ANG.)} 290 .ANG. ZrO.sub.2 (not
shown; 25-80 {acute over (.ANG.)} 25-50 {acute over (.ANG.)} 35
.ANG. optional)
[0027] The second IR reflecting layer comprising silver 19 is at
least as thick as the first IR reflecting layer comprising silver
9. In certain preferred embodiments, it has been found that
surprisingly beneficial results can be achieved when the second IR
reflecting layer comprising silver 19 is thicker than the first IR
reflecting layer comprising silver 9, more preferably when second
IR reflecting layer 19 is at least 10 angstroms (.ANG.) thicker,
more preferably at least 20 angstroms thicker, even more preferably
at least 30 angstroms thicker, still more preferably at least 40
angstroms thicker, still more preferably at least 50 angstroms
thicker, and most preferably at least 65 angstroms thicker) than
the first IR reflecting layer comprising silver 9. In certain
example embodiments, the second IR reflecting layer 19 of or
including Ag is at least twice as thick as the first IR reflecting
layer 9 of or including Ag. All thicknesses herein are physical
thicknesses.
[0028] In optional embodiments that including an overcoat (not
shown) of or including zirconium oxide and/or zirconium oxynitride,
that overcoat may be thinner than each of the IR reflecting layers
9, 19 comprising silver in the coating 30. In examples of such
embodiments, each of the IR reflecting layers 9 and 19 is at least
twice as thick, and more preferably at least three times as thick,
as the overcoat layer of or including zirconium oxide and/or
zirconium oxynitride.
[0029] In certain example embodiments, the center silicon nitride
based layer 14 is thicker than each of the other silicon nitride
based layers 3 and 24, preferably by at least 100 angstroms, more
preferably by at least 200 angstroms, and most preferably by at
least 300 angstroms. Moreover, in certain example embodiments, each
of the silicon nitride based layers 3, 14 and 24 is at least two
times as thick as one or both of the Ag-based IR reflecting layers
9 and 19.
[0030] The coating 30 offers good durability and allows for lower
glass side and outside visible reflection compared to a
single-silver based low-E coating.
[0031] In certain example embodiments of this invention, coated
articles herein may have the following optical and solar
characteristics when measured monolithically (before and/or after
optional HT). The sheet resistances (R.sub.s) herein take into
account all IR reflecting layers (e.g., silver layers 9, 19). Note
that "before heat treatment" means as annealed, but before high
temperature heat treatment such as thermal tempering as described
herein. Note also that E.sub.n refers to normal emissivity,
T.sub.vis refers to visible transmission, R.sub.gY refers to glass
side reflective visible reflectance, and the a* and b* values below
with a "g" subscript refers to glass side reflective a* and b*
color values respectively.
TABLE-US-00002 Optical/Solar Characteristics (Monolithic-Before
Heat Treatment) Characteristic General More Preferred Most
Preferred R.sub.s (ohms/sq.): <=5.0 <=4.0 <=3.6 E.sub.n:
<=0.08 <=0.05 <=0.04 T.sub.vis (Ill. C 2.degree.): 25-55%
30-50% 35-45% R.sub.gY (Ill. C, 2 deg.): <=11% <=10% <=9%
or <=8% a*.sub.g (Ill. C, 2.degree.): -4 to +2 -3 to +1 -2 to 0
b*.sub.g (Ill. C, 2.degree.): -7 to +2 -6 to 0 -5 to -3
TABLE-US-00003 Optical/Solar Characteristics (Monolithic-Post Heat
Treatment) Characteristic General More Preferred Most Preferred
R.sub.s (ohms/sq.): <=5.0 <=4.0 <=3.0 E.sub.n: <=0.08
<=0.05 <=0.04 T.sub.vis (Ill. C 2.degree.): 25-60% 25-55%
35-50% R.sub.gY (Ill. C, 2 deg.): <=11% <=10% <=9% or
<=8% a*.sub.g (Ill. C, 2.degree.): -4 to +5 -3 to +3 -2 to +2
b*.sub.g (Ill. C, 2.degree.): -8 to +6 -6 to +5 -3 to +3
[0032] It can be seen from the above that the heat treatment (e.g.,
thermal tempering) slightly increases the visible transmission of
the coated article.
[0033] In certain example IG window embodiments of this invention,
coated articles herein which have been optionally heat treated to
an extent sufficient for tempering, and which have been coupled to
another glass substrate to form an IG unit, may have the below
recited Optical/Solar characteristics in a structure as shown in
FIG. 2 (e.g., where the two glass sheets are each about 3.5 to 6 mm
thick of clear glass with about a 13-16 mm gap therebetween filled
with 90/10 argon/air).
TABLE-US-00004 Optical/Solar Characteristics (IG unit-non-HT)
Characteristic General More Preferred Most Preferred R.sub.s
(ohms/sq.): <=5.0 <=4.0 <=3.6 E.sub.n: <=0.08 <=0.05
<=0.04 T.sub.vis (Ill. C 2.degree.): 25-55% 25-50% 30-45%
RY.sub.outside(Ill. C, 2 deg.): <=11% <=10% <=9% or
<=8% a*.sub.outside (Ill. C, 2.degree.): -5 to +2 -4 to +1 -3 to
0 b*.sub.outside (Ill. C, 2.degree.): -7 to +2 -6 to 0 -5 to -3
U.sub.gvalue (W/m.sup.2K): <=1.20 <=1.17 <=1.16
TABLE-US-00005 Optical/Solar Characteristics (IG unit-Heat Treated)
Characteristic General More Preferred Most Preferred R.sub.s
(ohms/sq.): <=5.0 <=4.0 <=3.0 E.sub.n: <=0.08 <=0.05
<=0.04 T.sub.vis (Ill. C 2.degree.): 25-60% 25-50% 30-45%
RY.sub.outside(Ill. C, 2 deg.): <=11% <=10% <=9% or
<=8% a*.sub.outside (Ill. C, 2.degree.): -5 to +5 -4 to +2 -3 to
0 b*.sub.outside (Ill. C, 2.degree.): -8 to +6 -6 to +5 -5 to +3
U.sub.gvalue (W/m.sup.2K): <=1.20 <=1.17 <=1.16
[0034] The following examples of this invention are provided for
purposes of example only, and are not intended to be limiting
unless specifically claimed.
EXAMPLES 1-3
[0035] The following Examples 1-3 were made via sputtering coatings
on 6 mm thick clear and transparent glass substrates so as to have
approximately the layer thicknesses shown in the "example" column
in the chart above regarding layer thicknesses.
[0036] Set forth below are the optical characteristics of Examples
1-3 measured for a monolithic coated article as shown in FIG. 1.
All values measured in the table immediately below are pre-HT. Note
that "f" refers to film reflection, i.e., reflection from the film
side of the coated article, whereas "g" refers to glass side
reflection. Optics were taken III. C, 2 degree observer, unless
otherwise indicated.
TABLE-US-00006 Monolithic (Pre-HT) Characteristic Ex. 1 Ex. 2 Ex. 3
T.sub.vis (or TY)(Ill. C 2.degree.): 39.5% 39.7% 40.2% a*.sub.t
(Ill. C 2.degree.): -4.1 -6.6 -4.0 b*.sub.t (Ill. C 2.degree.):
-13.7 -12.2 -13.5 R.sub.fY (Ill. C, 2 deg.): 11.0% 13.2% 6.7%
a*.sub.f (Ill. C, 2.degree.): 18.3 18.8 24.6 b*.sub.f (Ill. C,
2.degree.): 28.2 8.5 27.9 R.sub.gY (Ill. C, 2 deg.): 6.6% 8.7% 6.5%
a*.sub.g (Ill. C, 2.degree.): -1.4 -0.3 3.6 b*.sub.g (Ill. C,
2.degree.): -3.0 -5.5 -1.2 L*.sub.g: 30.9 35.4 30.6 R.sub.s
(ohms/sq.): 3.6 n/a n/a
[0037] It can be seen from the above the examples above that the
coated articles measured monolithically had desirable low visible
transmission, and had desirable low glass side visible reflectance
and desirable glass side reflective color values. Glass side
visible reflection (RgY) was good in that it was below 10%, more
preferably no greater than 9%. These are desirable characteristics,
especially when the coated article is to be put in an IG window
unit as shown in FIG. 2.
TABLE-US-00007 Monolithic (post-HT) Characteristic Ex. 1 Ex. 2 Ex.
3 T.sub.vis (or TY)(Ill. C 2.degree.): 44.5% 43.9% 45.8% a*.sub.t
(Ill. C 2.degree.): -6.7 -7.9 -6.8 b*.sub.t (Ill. C 2.degree.):
-16.3 -15.0 -15.9 R.sub.fY (Ill. C, 2 deg.): 13.6% 15.6% 10.1%
a*.sub.f (Ill. C, 2.degree.): 17.4 17.3 21.2 b*.sub.f (Ill. C,
2.degree.): 32.4 15.0 28.6 R.sub.gY (Ill. C, 2 deg.): 7.2% 9.4%
8.6% a*.sub.g (Ill. C, 2.degree.): -1.1 -1.8 5.6 b*.sub.g (Ill. C,
2.degree.): -0.8 -3.3 4.9 L*.sub.g: 32.3 36.7 35.2
[0038] It can be seen from the above the examples above that the
coated articles measured monolithically had desirable low visible
transmission (T.sub.vis or TY), desirable low glass side visible
reflectance (R.sub.gY), and had fairly desirable glass side
reflective color. Glass side visible reflectance was good in that
it was below 10%. These are desirable characteristics, especially
when the coated article is to be put in an IG window unit as shown
in FIG. 2 so that the coating ends up on surface two of the IG
window unit.
[0039] The coated articles of Examples 1-3 were put in IG window
units as shown in FIG. 2, where glass substrate 1 was 6 mm thick
and was Guardian ExtraClear glass, glass substrate 2 was 4 mm thick
and was Guardian ExtraClear glass, gap 50 was 16 mm thick, and the
gap 50 was filed with 90% argon gas and 10% air. Set forth below
are the optical characteristics of IG window units including the
coated articles of Examples 1-3, namely when the coated articles
are located in IG window units as shown in FIG. 2 (on surface #2 of
the IG unit, so that glass side reflective values are indicative of
from the outside). The respective tables below demonstrate both
non-HT and HT versions oldie coated articles in respective IG
window units. The "non-HT" refers to annealed coated articles and
glass substrates in the IG units, while "HT" refers to thermally
tempered coated articles and glass substrates in the IG units. The
IG window units were grey/dark grey in appearance and this
appearance was achieved without using grey glass substrates
(instead, clear glass substrates were used, but the grey appearance
was still achieved due to the coating design). The IG units also
were desirable in that they realized low visible transmission, low
outside visible reflectance, low U-values and low solar
factors.
TABLE-US-00008 IG Unit (non-HT) Characteristic Ex. 1 Ex. 2 Ex. 3
T.sub.vis (or TY)(Ill. C 2.degree.): 36.2% 36.4% 36.7% a*.sub.t
(Ill. C 2.degree.): -4.3 -6.6 -4.2 b*.sub.t (Ill. C 2.degree.):
-12.9 -11.6 -13.9 R.sub.insideY (Ill. C, 2 deg.): 17.5% 19.4% 13.5%
a*.sub.inside (Ill. C, 2.degree.): 11.1 12.0 12.9
b*.sub.inside(Ill. C, 2.degree.): 13.6 4.7 10.1 R.sub.outsideY
(Ill. C, 2 deg.): 7.9% 10.1% 7.9% a*.sub.outside (Ill. C,
2.degree.): -1.7 -1.1 2.7 b*.sub.outside (Ill. C, 2.degree.): -5.8
-7.3 -4.4 U.sub.gvalue (W/m.sup.2K): 1.168 1.151 1.151 Solar Factor
(g-value): 25.8% 24.8% 25.5% Solar Factor (g-value, in .fwdarw.
out): 49.9% 48.0% 50.7%
TABLE-US-00009 IG Unit (HT) Characteristic Ex. 1 Ex. 2 Ex. 3
T.sub.vis (or TY)(Ill. C 2.degree.): 40.8% 40.3% 41.8% a*.sub.t
(Ill. C 2.degree.): -6.9 -7.9 -6.8 b*.sub.t (Ill. C 2.degree.):
-15.3 -14.3 -15.1 R.sub.insideY (Ill. C, 2 deg.): 19.5% 21.3% 16.7%
a*.sub.inside (Ill. C, 2.degree.): 11.2 11.4 12.6
b*.sub.inside(Ill. C, 2.degree.): 17.4 9.0 13.1 R.sub.outsideY
(Ill. C, 2 deg.): 8.9% 11.1% 10.4% a*.sub.outside (Ill. C,
2.degree.): -2.0 -2.7 4.1 b*.sub.outside (Ill. C, 2.degree.): -5.0
-6.3 -0.3 U.sub.gvalue (W/m.sup.2K): 1.151 1.151 1.151 Solar Factor
(g-value): 27.5% 26.5% 27.4% Solar Factor (g-value, in .fwdarw.
out): 48.6% 47.3% 49.2%
[0040] While the invention has been described in connection with
what is presently considered to be the most practical and preferred
embodiment, it is to be understood that the invention is not to be
limited to the disclosed embodiment, but on the contrary, is
intended to cover various modifications and equivalent arrangements
included within the spirit and scope of the appended claims.
* * * * *