U.S. patent application number 16/747123 was filed with the patent office on 2020-05-14 for transparent conductive coating for capacitive touch panel and method of making same.
This patent application is currently assigned to GUARDIAN GLASS, LLC. The applicant listed for this patent is GUARDIAN GLASS, LLC. Invention is credited to Willem DEN BOER, Alexey KRASNOV.
Application Number | 20200150802 16/747123 |
Document ID | / |
Family ID | 62108464 |
Filed Date | 2020-05-14 |
![](/patent/app/20200150802/US20200150802A1-20200514-D00000.png)
![](/patent/app/20200150802/US20200150802A1-20200514-D00001.png)
![](/patent/app/20200150802/US20200150802A1-20200514-D00002.png)
![](/patent/app/20200150802/US20200150802A1-20200514-D00003.png)
![](/patent/app/20200150802/US20200150802A1-20200514-D00004.png)
![](/patent/app/20200150802/US20200150802A1-20200514-D00005.png)
![](/patent/app/20200150802/US20200150802A1-20200514-D00006.png)
![](/patent/app/20200150802/US20200150802A1-20200514-D00007.png)
![](/patent/app/20200150802/US20200150802A1-20200514-D00008.png)
![](/patent/app/20200150802/US20200150802A1-20200514-D00009.png)
![](/patent/app/20200150802/US20200150802A1-20200514-D00010.png)
View All Diagrams
United States Patent
Application |
20200150802 |
Kind Code |
A1 |
KRASNOV; Alexey ; et
al. |
May 14, 2020 |
TRANSPARENT CONDUCTIVE COATING FOR CAPACITIVE TOUCH PANEL AND
METHOD OF MAKING SAME
Abstract
A multi-layer conductive coating is substantially transparent to
visible light, contains at least one conductive layer comprising
silver that is sandwiched between at least a pair of dielectric
layers, and may be used as an electrode and/or conductive trace in
a capacitive touch panel. The multi-layer conductive coating may
contain a dielectric layer(s), and may be used in applications such
as capacitive touch panels for controlling showers, appliances,
vending machines, electronics, electronic devices, and/or the like.
In certain example embodiments, different electrodes of the touch
panel may be formed by different silver based layers of the same or
different multi-layer coatings. In patterning the electrodes,
different laser scribing wavelengths may be used to pattern
different respective silver based layers, of the same or different
multi-layer coating(s), in certain example embodiments.
Inventors: |
KRASNOV; Alexey; (Canton,
MI) ; DEN BOER; Willem; (Brighton, MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
GUARDIAN GLASS, LLC |
AUBURN HILLS |
MI |
US |
|
|
Assignee: |
GUARDIAN GLASS, LLC
AUBURN HILLS
MI
|
Family ID: |
62108464 |
Appl. No.: |
16/747123 |
Filed: |
January 20, 2020 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
16371190 |
Apr 1, 2019 |
10540047 |
|
|
16747123 |
|
|
|
|
15867917 |
Jan 11, 2018 |
10248274 |
|
|
16371190 |
|
|
|
|
15678266 |
Aug 16, 2017 |
9921703 |
|
|
15867917 |
|
|
|
|
15647541 |
Jul 12, 2017 |
9904431 |
|
|
15678266 |
|
|
|
|
15215908 |
Jul 21, 2016 |
9733779 |
|
|
15647541 |
|
|
|
|
15146270 |
May 4, 2016 |
9740357 |
|
|
15215908 |
|
|
|
|
13685871 |
Nov 27, 2012 |
9354755 |
|
|
15146270 |
|
|
|
|
15678266 |
Aug 16, 2017 |
9921703 |
|
|
15867917 |
|
|
|
|
15409658 |
Jan 19, 2017 |
10082920 |
|
|
15678266 |
|
|
|
|
14681266 |
Apr 8, 2015 |
9557871 |
|
|
15409658 |
|
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G06F 3/044 20130101;
G06F 2203/04111 20130101; G06F 2203/04103 20130101; G06F 3/0416
20130101; G02F 1/13338 20130101; G06F 3/0412 20130101 |
International
Class: |
G06F 3/044 20060101
G06F003/044; G06F 3/041 20060101 G06F003/041; G02F 1/1333 20060101
G02F001/1333 |
Claims
1-49. (canceled)
50. A capacitive touch panel, comprising: a substrate; a
multi-layer transparent conductive coating supported by the
substrate, the multi-layer transparent conductive coating including
a first conductive layer, a first dielectric layer comprising
silicon nitride located between at least the substrate and the
first conductive layer, and a second dielectric layer comprising
one or more of: zirconium oxide, silicon nitride, and tin oxide,
located over at least the first conductive layer; each of said
layers of the multi-layer transparent conductive coating being
provided in substantially the same shape as viewed from above, so
that no layer of the coating is patterned so as expose an area of
an underlying layer of the coating; at least one electrode
configured for allowing touch position to be determined, and
comprising the multi-layer transparent conductive coating; and a
processor configured for determining touch position on the touch
panel.
51. The capacitive touch panel of claim 50, wherein the at least
one electrode comprises: a first set of electrodes oriented
substantially perpendicular to electrodes of a second set of
electrodes, as viewed from above.
52. The capacitive touch panel of claim 50, wherein the conductive
layer comprises silver and is doped.
53. The capacitive touch panel of claim 52, wherein the conductive
layer comprising silver is doped with from about 0.05 to 3.0% (wt.
%) of one or more of Zn, Pt, Pd, Ti, and Al.
54. The capacitive touch panel of claim 50, wherein the conductive
layer comprises Ni and/or Cr.
55. The capacitive touch panel of claim 50, wherein the transparent
conductive coating has a sheet resistance of less than or equal to
about 40 ohms/square.
56. The capacitive touch panel of claim 50, wherein the second
dielectric layer comprises silicon nitride.
Description
[0001] This application is a continuation-in-part (CIP) of U.S.
Ser. No. 15/678,266, filed Aug. 16, 2017, which is a
continuation-in-part (CIP) of U.S. Ser. No. 15/647,541 filed Jul.
12, 2017, which is a continuation of U.S. Ser. No. 15/215,908 filed
Jul. 21, 2016 (U.S. Pat. No. 9,733,779), which is a
continuation-in-part (CIP) of U.S. Ser. No. 15/146,270 filed May 4,
2016, which is a continuation of U.S. Ser. No. 13/685,871 filed
Nov. 27, 2012 (now U.S. Pat. No. 9,354,755), the disclosures of
which are all hereby incorporated herein by reference in their
entireties. This application is also a continuation-in-part (CIP)
of U.S. Ser. No. 15/678,266, filed Aug. 16, 2017, which is a
continuation-in-part (CIP) of U.S. Ser. No. 15/409,658 filed Jan.
19, 2017, which is a continuation of U.S. Ser. No. 14/681,266 filed
Apr. 8, 2015 (now U.S. Pat. No. 9,557,871), the disclosures of
which are all hereby incorporated herein by reference in their
entireties.
[0002] Example embodiments of this invention relate to a
multi-layer conductive coating that is substantially transparent to
visible light, contains at least one conductive layer comprising
silver that is sandwiched between at least a pair of dielectric
layers, and may be used as an electrode and/or conductive trace in
a capacitive touch panel. The multi-layer conductive coating may
contain a layer of or including zirconium oxide (e.g., ZrO.sub.2)
and/or silicon nitride in certain embodiments, and may be used in
applications such as capacitive touch panels for controlling
showers, appliances, vending machines, electronics, electronic
devices, and/or the like. The coating has improved conductivity
(e.g., smaller sheet resistance R.sub.s or smaller emissivity,
given a similar thickness and/or cost of deposition) compared to
typical ITO coatings used in touch panels. In certain example
embodiments, different electrodes of the touch panel may be formed
by different silver based layers of the same or different
multi-layer coatings. In patterning the electrodes, different laser
scribing wavelengths may be used to pattern different respective
silver based layers, of the same or different multi-layer
coating(s), in certain example embodiments. Different electrodes
may be patterned from the same or different sides of a supporting
glass substrate in different example embodiments.
BACKGROUND
[0003] A capacitive touch panel often includes an insulator such as
glass, coated with a conductive coating. As the human body is also
an electrical conductor, touching the surface of the panel results
in a distortion of the panel's electrostatic field, measurable as a
change in capacitance for example. A transparent touch panel may be
combined with a display such as a liquid crystal display (LCD) or
LED panel to form a touchscreen. A projected capacitive (PROCAP)
touch panel, which may optionally include an LCD or other display,
allows finger or other touches to be sensed through a protective
layer(s) in front of the conductive coating.
[0004] FIGS. 1(a) to 1(g) illustrate an example of a related art
projected capacitive touch panel, e.g., see U.S. Pat. No. 8,138,425
the disclosure of which is hereby incorporated herein by reference.
Referring to FIG. 1(a), substrate 11, x-axis conductor 12 for rows,
insulator 13, y-axis conductor 14 for columns, and conductive
traces 15 are provided. Substrate 11 may be a transparent material
such as glass. X-axis conductors 12 and y-axis conductors 14 are
typically indium tin oxide (ITO) which is a transparent conductor.
Insulator 13 may be an insulating material (for example, silicon
nitride) which inhibits conductivity between x-axis conductors 12
and y-axis conductors 14. Traces 15 provide electrical conductivity
between the plurality of conductors and a signal processor (not
shown). ITO used for electrodes/traces in small PROCAP touch panels
typically has a sheet resistance of at least about 100 ohms/square,
which has been found to be too high for certain applications.
Moreover, conventional ITO coatings for touch panels are typically
highly crystalline and relatively thick and brittle, and thus in
applications involving bending such ITO coatings are subject to
failure.
[0005] Referring to FIG. 1(b), x-axis conductor 12 (e.g., ITO) is
formed on substrate 11. The ITO is coated in a continuous layer on
substrate 11 and then is subjected to a first photolithography
process in order to pattern the ITO into x-axis conductors 12. FIG.
1(c) illustrates cross section A-A' of FIG. 1(b), including x-axis
conductor 12 formed on substrate 11. Referring to FIG. 1(d),
insulator 13 is then formed on the substrate 11 over x-axis
channel(s) of x-axis conductor 12. FIG. 1(e) illustrates cross
section B-B' of FIG. 1(d), including insulator 13 which is formed
on substrate 11 and x-axis conductor 12. The insulator islands 13
shown in FIGS. 1(d)-(e) are formed by depositing a continuous layer
of insulating material (e.g., silicon nitride) on the substrate 11
over the conductors 12, and then subjecting the insulating material
to a second photolithography, etching, or other patterning process
in order to pattern the insulating material into islands 13.
Referring to FIG. 1(f), y-axis conductors 14 are then formed on the
substrate over the insulator islands 13 and x-axis conductors 12.
The ITO for y-axis conductors 14 is coated on substrate 11 over 12,
13, and then is subjected to a third photolithography or other
patterning process in order to pattern the ITO into y-axis
conductors 14. While much of y-axis conductor material 14 is formed
directly on substrate 11, the y-axis channel is formed on insulator
13 to inhibit conductivity between x-axis conductors 12 and y-axis
conductors 14. FIG. 1(g) illustrates cross section C-C' of FIG.
1(f), including part of an ITO y-axis conductor 14, which is formed
on the substrate 11 over insulative island 13 and over an example
ITO x-axis conductor 12. It will be appreciated that the process of
manufacturing the structure shown in FIGS. 1(a)-(g) requires three
separate and distinct deposition steps and three photolithography
type processes, which renders the process of manufacture
burdensome, inefficient, and costly.
[0006] FIG. 1(h) illustrates another example of an intersection of
ITO x-axis conductor 12 and ITO y-axis conductor 14 according to a
related art projected capacitive touch panel. Referring to FIG.
1(h), an ITO layer is formed on the substrate 11 and can then be
patterned into x-axis conductors 12 and y-axis conductors 14 in a
first photolithography process. Then, an insulating layer is formed
on the substrate and is patterned into insulator islands 13 in a
second photolithography or etching process. Then, a conductive
layer is formed on the substrate 11 over 12-14 and is patterned
into conductive bridges 16 in a third photolithography process.
Bridge 16 provides electrical conductivity for a y-axis conductor
14 over an x-axis conductor 12. Again, this process of manufacture
requires at least three deposition steps and at least three
different photolithography processes.
[0007] The projected capacitive touch panels illustrated in FIGS.
1(a) through 1(h) may be mutual capacitive devices or
self-capacitive devices. In a mutual capacitive device, there is a
capacitor at every intersection between an x-axis conductor 12 and
a y-axis conductor 14 (or metal bridge 16). A voltage is applied to
x-axis conductors 12 while the voltage of y-axis conductors 14 is
measured (and/or vice versa). When a user brings a finger or
conductive stylus close to the surface of the device, changes in
the local electrostatic field reduce the mutual capacitance. The
capacitance change at every individual point on the grid can be
measured to accurately determine the touch location. In a
self-capacitive device, the x-axis conductors 12 and y-axis
conductors 14 operate essentially independently. With
self-capacitance, the capacitive load of a finger or the like is
measured on each x-axis conductor 12 and y-axis conductor 14 by a
current meter.
[0008] As described above, prior art transparent conductors 12 and
14 in touch panels are typically indium tin oxide (ITO), which is
problematic for a number of reasons. First, ITO is costly. Second,
thin layers of ITO have a high sheet resistance R.sub.s (typically
at least about 100 ohms/square at a given thickness); in other
words the conductivity of ITO is not particularly good and its
resistivity is high. In order for an ITO layer to have a much lower
sheet resistance, the ITO layer must be extremely thick (for
example, greater than 300 or 400 nm). However, such a thick layer
of ITO is both prohibitively expensive and less transparent. Thus,
the high sheet resistance of thin layers of ITO limits their use in
layouts requiring long narrow traces on touch panels, with an
emphasis on large panels. Accordingly, it will be appreciated that
there exists a need in the art for touch panel electrodes that are
of material which does not suffer from the ITO disadvantage
combination of high cost and low conductivity at small
thicknesses.
SUMMARY OF EXAMPLE EMBODIMENTS
[0009] Example embodiments of this invention relate to a
multi-layer conductive coating that is substantially transparent to
visible light, contains at least one conductive layer comprising
silver that is sandwiched between at least a pair of dielectric
layers, and may be used as an electrode and/or conductive trace in
a capacitive touch panel. The multi-layer conductive coating may
contain a dielectric layer(s) of or including zirconium oxide
(e.g., ZrO.sub.2) and/or silicon nitride in certain example
embodiments, and may be used in applications such as capacitive
touch panels for controlling showers, appliances, vending machines,
electronics, electronic devices, and/or the like. The coating has
improved conductivity (e.g., smaller sheet resistance R.sub.s or
smaller emissivity, given a similar thickness and/or cost of
deposition) compared to typical ITO coatings used in touch panels.
The coating may be used as electrode layers and/or traces in
capacitive touch panels such as PROCAP touch panel or any other
type of touch panel.
[0010] In certain example embodiments, different electrodes of the
touch panel may be formed by different silver based layers of the
same or different multi-layer coatings. In patterning the
electrodes, different laser scribing wavelengths may be used to
pattern different respective silver based layers, of the same or
different multi-layer coating(s), in certain example embodiments.
For example, when first and second electrodes of the touch panel
overlap each other, a first laser scribing wavelength may be used
when patterning the first silver based layer into the first
electrode(s), and a second laser scribing wavelength may be used
when patterning the second silver based layer into the second
electrode(s). For example, transmit electrodes may be laser
patterned using a first wavelength(s), and receive electrodes may
be laser patterned using a different second wavelength(s).
Advantageously, the use of the different wavelengths reduces damage
to electrode(s) not intended to be patterned in a given
procedure.
[0011] In certain example embodiments, when different electrodes of
the touch panel may be formed by different silver based layers of
the same or different multi-layer coatings, a first set of
electrodes may be patterned by laser scribing from a first side of
the supporting glass substrate, whereas a second set of electrodes
may be patterned by laser scribing from an opposite second side of
the supporting glass substrate. Thus, since the electrodes are on
the same side of the glass substrate, one of the two laser
patterning procedures is performed through the supporting glass
substrate. For example, transmit electrodes may be laser patterned
from a first side of the supporting glass substrate, whereas
receive electrodes may be laser patterned form the opposite second
side of the supporting glass substrate. Advantageously, this
technique reduces damage to electrodes not intended to be patterned
in a given laser patterning procedure. The embodiment involving
laser patterning of different electrodes from opposite sides of the
supporting glass substrate may, or may not, be used in combination
with the embodiment using different wavelengths to pattern
different electrodes.
[0012] In certain example embodiments, the coating for at least one
electrode of the touch panel may have increased resistance, and
thus reduced conductivity, compared to pure silver layers of
certain coatings, in order to allow the silver-based coating to be
more suitable for touch panel electrode applications. The increased
resistance, and thus reduced conductivity, of the silver layer(s)
in the coating may be achieved by any of several techniques. For
example, the increased resistance, and thus the reduced
conductivity, of the silver layer(s) in the coating may be achieved
by doping the silver with an impurity such as one or more of Zn,
Pt, Pd, Ti, Al or the like, and/or by replacing crystalline zinc
oxide directly under and contacting the silver with another
material such as a suitable non-crystalline dielectric, amorphous
semiconductor, or metal alloy (e.g., NiCr) in order to increase the
silver's resistance. Silver with increased resistance may be used
for all electrodes and/or traces in the touch panel, or
alternatively may be done for only a portion of the electrodes
and/or traces in the touch panel.
[0013] In certain example embodiments, different electrodes of the
touch panel may have different resistance, with respective
silver-based structures of various electrodes being different from
one another to provide different resistance for different
electrodes. For example, transmit electrodes may have higher sheet
resistance (ohms/square) than receive electrodes in certain example
embodiments. Thus, for example, one, some, or all of the transmit
electrodes may be made up of a multi-layer coating including a
silver layer that has higher sheet resistance (and thus lower
conductivity) compared to pure silver in certain types of coatings,
with the higher sheet resistance of the silver-based layer being
achieved by doping the silver with an impurity such as one or more
of Zn, Pt, Pd, Ti, Al or the like, and/or by replacing crystalline
zinc oxide directly under and contacting the silver with another
material such as a suitable non-crystalline dielectric, amorphous
semiconductor, or metal alloy (e.g., NiCr) in order to increase the
silver's resistance. The differences in resistance between transmit
and receive electrodes may also be realized by: making conductors
of these electrodes different thicknesses, doping silver of the
transmit electrodes, and/or providing silver of the transmit
electrodes over and directly contacting a layer other than a
crystalline zinc oxide based layer.
[0014] In an example embodiment of this invention, there is
provided a method of making a capacitive touch panel comprising a
glass substrate; a patterned multi-layer transparent conductive
coating supported by the substrate, the multi-layer transparent
conductive coating including a first conductive layer comprising
silver, a dielectric layer located between at least the substrate
and the first conductive layer comprising silver, and a dielectric
layer comprising one or more of: zirconium oxide, silicon nitride,
and tin oxide, located over at least the first conductive layer
comprising silver; a first set of electrodes; a second set of
electrodes; wherein the first and second sets of electrodes are
configured for allowing touch position to be determined, wherein at
least some of the electrodes comprise the multi-layer transparent
conductive coating; the method comprising: laser patterning the
first conductive layer comprising silver with a first wavelength in
forming the first set of electrodes; and forming the second set of
electrodes by laser patterning (i) with a second wavelength
different from the first wavelength, and/or (ii) with a laser beam
from an opposite side of the substrate than a laser beam used in
laser patterning the first conductive layer. The patterned
multi-layer transparent conductive coating may further comprise a
second conductive layer comprising silver, and another dielectric
layer (e.g., silicon nitride or tin oxide) located between at least
the first and second conductive layers comprising silver, wherein
the first set of electrodes and the second set of electrodes may
each comprise the multi-layer transparent conductive coating, and
wherein said forming the second set of electrodes by laser
patterning with the second wavelength different from the first
wavelength may comprise laser patterning the second conductive
layer comprising silver with the second wavelength. The first
conductive layer comprising silver of the patterned multi-layer
transparent conductive coating may be a conductor of the first set
of electrodes, and the second conductive layer comprising silver of
the patterned multi-layer transparent conductive coating may be a
conductor of the second set of electrodes.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIGS. 1(a) to 1(h) illustrate examples of prior art
projected capacitive touch panels.
[0016] FIG. 2(a) illustrates a top or bottom plan layout of a
projected capacitive touch panel according to an exemplary
embodiment, that may contain the coating(s) of FIGS. 4, 6, 7,
and/or 8 as conductive electrode(s) and/or conductive trace(s).
[0017] FIG. 2(b) illustrates a schematic representation of
circuitry for the projected capacitive touch panel of FIG. 2(a), 3,
9, and/or 10.
[0018] FIG. 3(a) illustrates a top or bottom plan layout of a
projected capacitive touch panel according to another example
embodiment, that may contain the coating(s) of FIGS. 4, 6, 7,
and/or 8 as conductive electrode(s) and/or conductive trace(s).
[0019] FIG. 3(b) illustrates a top or bottom plan layout of a
projected capacitive touch panel electrode arrangement according to
another example embodiment, that may contain the coating(s) of
FIGS. 4, 6, 7, and/or 8 as conductive electrode(s) and/or
conductive trace(s).
[0020] FIG. 3(c) illustrates a top or bottom plan layout of a
projected capacitive touch panel electrode arrangement according to
another example embodiment, that may contain the coating(s) of
FIGS. 4, 6, 7, and/or 8 as conductive electrode(s) and/or
conductive trace(s).
[0021] FIG. 3(d) is a perspective view of part of a capacitive
touch panel electrode arrangement according to an example
embodiment of this invention, where transmit electrodes have higher
resistance than do receive electrodes.
[0022] FIG. 3(e) is a perspective view of part of a capacitive
touch panel electrode arrangement according to an example
embodiment of this invention, where transmit electrodes have higher
resistance than do receive electrodes.
[0023] FIG. 3(f) is a top view of part of a capacitive touch panel
electrode arrangement according to an example embodiment of this
invention, where transmit electrodes and receive electrodes overlap
and are substantially orthogonal to one another on different
planes.
[0024] FIG. 3(g) is a cross sectional view of the capacitive touch
panel electrode arrangement of FIG. 3(f) along sectional line
a-a'.
[0025] FIGS. 4(a)-4(h) are cross-sectional views of various
silver-inclusive transparent conductive coatings for use in a touch
panel of FIGS. 2, 3, 7, 8, 9, 10, 11, 12, 13 and/or 14 according to
exemplary embodiments of this invention.
[0026] FIG. 5 is a percent visible transmission/reflectance vs.
wavelength (nm) graph illustrating the visible transmission (TR)
percentage and glass side visible reflection (BRA) percentage of a
Comparative Example (CE) coating on a glass substrate, compared to
those values for the glass substrate alone (Glass-TR,
Glass-BRA).
[0027] FIG. 6 is a percent visible transmission/reflectance vs.
wavelength (nm) graph illustrating the visible transmission (TR)
and glass side visible reflection (BRA) of an example coating of
FIG. 4(a) according to an example embodiment of this invention on a
glass substrate, demonstrating that it is transparent to visible
light and has glass side visible reflectance more closely matched
to that of the glass substrate compared to the CE in FIG. 5. FIG.
6, like FIG. 5, also illustrates the visible transmission
(Glass-TR) and visible reflectance (Glass-BRA) for the glass
substrate alone without the coating on it.
[0028] FIG. 7 is a cross sectional view of a touch panel assembly
according to an example embodiment of this invention, including a
touch panel according to any of FIGS. 2-4, 6, 8-10 coupled to a
liquid crystal panel, for use in electronic devices such as
portable phones, portable pads, computers, and/or so forth.
[0029] FIG. 8(a) is a percent visible transmission/reflectance vs.
wavelength (nm) graph illustrating the visible transmission (CGN-TR
or TR) and glass side visible reflection (CGN-BRA or BRA) of an
example coating of FIG. 4(b) according to another example
embodiment of this invention, demonstrating that it is transparent
to visible light and has a glass side visible reflectance more
closely matched to the reflectance of the glass substrate alone
compared to the CE. FIG. 8(a) also illustrates the visible
transmission (Glass-TR) and visible reflectance (Glass-BRA) for
just the glass substrate absent the coating.
[0030] FIG. 8(b) is a percent visible transmission/reflectance vs.
wavelength (nm) graph illustrating the visible transmission (CGN-TR
or TR) and glass side visible reflection (CGN-BRA or BRA) of an
example coating of FIG. 4(c) according to another example
embodiment of this invention, demonstrating that it is transparent
to visible light and has a glass side visible reflectance more
closely matched to the reflectance of the substrate compared to the
CE.
[0031] FIG. 9 illustrates a top or bottom plan layout of a low
resolution capacitive touch panel according to another example
embodiment, that may contain the coating(s) of FIGS. 4, 6, 7, 8 as
conductive electrode(s) and/or conductive trace(s).
[0032] FIG. 10 is a cross sectional view of a low resolution
capacitive touch panel according to another example embodiment
where the substrate supporting the coating of this invention of
FIG. 9 may be laminated to another substrate (e.g., glass) via a
polymer inclusive interlayer such as PVB or EVA.
[0033] FIG. 11 is a flow chart of a process for making the
transparent conductive coating pattern according to any of FIG. 2,
3, 4, 7, 8, 9, or 10 according to an example embodiment of this
invention.
[0034] FIG. 12 is a flow chart of a process for making the
transparent conductive coating pattern according to any of FIG. 2,
3, 4, 7, 8, 9, or 10 according to another example embodiment of
this invention.
[0035] FIG. 13 is a flow chart of a process for making the
transparent conductive coating pattern according to any of FIG. 2,
3, 4, 7, 8, 9, or 10 according to another example embodiment of
this invention.
[0036] FIG. 14(a) is a flow chart of a process for making the
transparent conductive coating pattern according to any of FIG. 2,
3, 4, 7, 8, 9, or 10 according to another example embodiment of
this invention.
[0037] FIG. 14(b) is a wavelength (nm) vs. absorption (%)
illustrating that different silver based layers in a multilayer
coating have different absorption characteristic based on
wavelength.
[0038] FIG. 15 is a cross sectional view of a capacitive touch
panel according to an example embodiment of this invention,
including the transparent conductive coating pattern according to
any of FIG. 2, 3, 4, 7, 8, 9, or 10 on surface #2, and an
additional functional film provided on the surface adapted to be
touched by a user.
[0039] FIG. 16 is a cross sectional view of a capacitive touch
panel according to another example embodiment of this invention,
including the transparent conductive coating pattern according to
any of FIG. 2, 3, 4, 7, 8, 9, or 10 on surface #3, and an
additional functional film provided on the surface adapted to be
touched by a user.
[0040] FIG. 17 is a cross sectional view of a monolithic capacitive
touch panel according to another example embodiment of this
invention, including the transparent conductive coating pattern
according to any of FIG. 2, 3, 4, 7, 8, 9, or 10 on surface #2, and
an additional functional film provided on the surface adapted to be
touched by a user.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0041] A detailed description of exemplary embodiments is provided
with reference to the accompanying drawings. Like reference
numerals indicate like parts throughout the drawings.
[0042] Example embodiments of this invention relate to a
multi-layer conductive coating 41 that is substantially transparent
to visible light, contains at least one conductive layer comprising
silver 46 that is sandwiched between at least a pair of layers such
as dielectric layers, and may be used as an electrode and/or
conductive trace in a capacitive touch panel. Example multi-layer
transparent conductive coatings 41 are shown in FIGS. 4(a)-(h). The
multi-layer conductive coating 41 may be used in applications such
as capacitive touch panels for controlling showers (e.g., water
on/off control, water temperature control, and/or steam control),
appliances, vending machines, music control, thermostat control,
electronics, electronic devices, and/or the like. The zirconium
oxide and/or DLC layers discussed herein provide for scratch
resistance, and resistance to stains and cleaning chemicals in
applications such as shower door/wall touch panel applications. In
certain example embodiments, the coating includes a silver layer(s)
46 and may be used as an electrode(s) and/or conductive trace(s) in
a capacitive touch panel so as to provide for an electrode(s)
transparent to visible light but without much visibility due to
closely matching visible reflection of the coating on the substrate
to that of an underlying substrate in areas where the coating is
not present. The coating 41 has improved conductivity (e.g.,
smaller sheet resistance R.sub.s or smaller emissivity, given a
similar thickness and/or cost of deposition) compared to typical
ITO coatings used in touch panels. The coating may be used as
electrode layers and/or traces in capacitive touch panels such as
PROCAP touch panels or any other type of touch panel. The touch
panels discussed herein, including the electrodes and traces of the
multi-layer coating 41, preferably have a visible transmission
(Ill. A, 2 deg. Obs.) of at least 50%, more preferably of at least
60%, and most preferably of at least 70%.
[0043] In certain example embodiments, the coating 41 for at least
one electrode in the touch panel may have increased resistivity,
and thus reduced conductivity, compared to pure silver layers of
certain coatings, in order to allow the silver-based coating to be
more suitable for certain touch panel electrode applications. The
increased sheet resistance, and reduced conductivity, of the silver
layer(s) 46 in the coating 41 may be achieved by any of several
techniques. For example, the increased sheet resistance, and
reduced conductivity, of the silver layer(s) 46 in the coating may
be achieved by doping the silver with an impurity such as one or
more of Zn, Pt, Pd, Ti, Al or the like. For example, the silver
layer 46 of any of FIGS. 4(a)-4(h) may be doped with from about
0.05 to 3.0%, more preferably from about 0.1 to 2.0%, and most
preferably from about 0.1 to 0.5% (wt. %), of one or more of Zn,
Pt, Pd, Ti, Al, or a combination thereof. The increased sheet
resistance, and reduced conductivity, of the silver layer(s) 46 may
also or instead be achieved by replacing crystalline zinc oxide 44
directly under and contacting the silver with another material such
as a suitable non-crystalline dielectric, amorphous semiconductor,
or metal alloy (e.g., NiCr, NiCrMo, etc.) in order to increase the
silver's resistance (e.g., see the NiCr based layer under the
silver in FIG. 4(f)). The increased sheet resistance, and reduced
conductivity, of the silver based layer(s) 46 may be achieved by,
for example, one or both of: (a) doping the silver, and/or (b)
replacing crystalline zinc oxide 44 directly under the silver with
a suitable non-crystalline dielectric, amorphous semiconductor, or
metal alloy. Silver with increased sheet resistance may be used for
all electrodes and/or traces in the touch panel, or alternatively
may be used for only a portion of the electrodes and/or traces in
the touch panel.
[0044] In certain example embodiments, different electrodes 41 of
the touch panel may be designed to have different sheet
resistances, with respective silver-based structures of various
electrodes being different from one another to provide different
sheet resistances for different electrodes. For example, transmit
electrodes (T) may have higher sheet resistance than receive
electrodes (R) in certain example embodiments. Thus, for example,
one, some, or all of the transmit electrodes (T) in any embodiment
herein may be made up of a multi-layer coating 41 including a
silver layer 46 that has higher sheet resistance (and thus lower
conductivity) compared to pure silver in certain types of coatings,
with the higher sheet resistance of the silver-based layer 46 being
achieved by doping the silver with an impurity such as one or more
of Zn, Pt, Pd, Ti, Al or the like, and/or by replacing crystalline
zinc oxide directly under and contacting the silver with another
material such as a suitable non-crystalline dielectric, amorphous
semiconductor, or metal alloy (e.g., NiCr) in order to increase the
silver based layer's sheet resistance. The receive electrodes may
be designed to have a lower sheet resistance than the transmit
electrodes, such as by not doping the silver based receive
electrodes and/or by providing them on and contacting a crystalline
or substantially crystalline layer of or including zinc oxide 44
which may optionally be doped with from about 1-10%, more
preferably from about 1-5% aluminum.
[0045] In certain example embodiments of this invention, there is
provided a capacitive touch panel that includes a glass substrate
40; a multi-layer transparent conductive coating 41 supported by
the glass substrate 40. The multi-layer transparent conductive
coating 41 may include at least one conductive layer comprising
silver 46, a layer 44 under the conductive layer comprising silver
46, and a dielectric layer comprising one or more of silicon
nitride 50, tin oxide 49, titanium oxide 48, NiCrO.sub.x 47 and/or
zirconium oxide 75 over the conductive layer comprising silver 46,
a plurality of electrodes and a plurality of conductive traces,
wherein the electrodes and/or the conductive traces of the touch
panel are made of the multi-layer transparent conductive coating
41. A processor (including processing circuitry) may be provided
for detecting touch position on the touch panel; wherein the
electrodes, and the conductive traces may be formed substantially
in a common plane substantially parallel to the glass substrate 40,
and a plurality of the electrodes are electrically connected to the
processor by conductive traces. The glass substrate may be heat
treated (e.g., thermally tempered). For one or more electrode(s)
and/or trace(s), increased resistance, and reduced conductivity, of
the silver in coating 41 compared to pure silver in certain
coatings may be achieved by, for example, one or both of: (a)
doping the conductive silver layer 46 with an impurity such as one
or more of Zn, Pt, Pd, Ti, Al, or a combination thereof, and/or (b)
replacing crystalline zinc oxide directly under the conductive
silver 46 with a suitable non-crystalline dielectric [e.g., silicon
oxide (e.g., SiO.sub.2), silicon oxynitride, silicon nitride (e.g.,
Si.sub.3N.sub.4), titanium oxide (e.g., TiO.sub.2), or zinc
stannate], amorphous semiconductor (e.g., a-Si), or metal alloy
(e.g., NiCr, NiCrMo, or the like).
[0046] The multi-layer transparent conductive coating 41 (and thus
silver based layer 46 in certain example embodiments) may have a
sheet resistance (R.sub.s) of less than or equal to about 40
ohms/square, more preferably less than or equal to about 20
ohms/square, more preferably less than or equal to about 15
ohms/square, and most preferably less than or equal to about 10
ohms/square. The multi-layer transparent conductive coating 41, and
thus silver based layer 46, may have a resistivity of from
30.times.10.sup.-7 to 90.times.10.sup.-7 .OMEGA.cm, more preferably
from 40.times.10.sup.-7 to 80.times.10.sup.-7 .OMEGA.cm
(ohmcm).
[0047] FIG. 2(a) illustrates a top or bottom plan layout of a
projected capacitive touch panel according to an exemplary
embodiment, that may contain the multi-layer conductive transparent
coating 41 of FIGS. 4, 6, 7, and/or 8 as conductive electrode(s) x,
y and/or conductive trace(s) 22. Referring to FIG. 2(a), touch
panel 20 is provided. Touch panel 20 includes a matrix of
electrodes x, y including n columns and m rows, provided on a
substrate 40 such as a glass substrate. The glass substrates may
also include an antireflective (AR) layer in certain example
embodiments. The matrix of row/column electrodes x, y may be
provided on the side of the substrate (e.g., glass substrate 40)
that is opposite the side touched by person(s) using the touch
panel, in order to prevent corrosion of the silver-based coating 41
by human finger touches. In other words, when the touch panel is
touched by a finger, stylus, or the like, the glass substrate 40 is
typically located between (a) the finger and (b) the matrix of
row/column electrodes x, y and conductive traces 22. However, in
certain embodiments the matrix of row/column electrodes x, y and
traces may be provided on the side of the substrate (e.g., glass
substrate 40) that is touched by person(s) using the touch panel,
such as in shower door application, glass wall applications, and/or
the like, for example in situations where only one glass substrate
is provided. Change in capacitance between adjacent row and column
electrodes in the matrix as a result of the proximity of a finger
or the like is sensed by the electronic circuitry, and the
connected circuitry can thus detect where the panel is being
touched by a finger or the like. For example, referring to FIG.
2(a), row 0 includes row electrodes x.sub.0,0, x.sub.1,0,
x.sub.2,0, etc., through x.sub.n,0 and columns 0, 1 and 2
respectively include column electrodes y.sub.0, y.sub.1, y.sub.2,
etc., through y.sub.n. Optionally, the x electrodes in a column
direction may also be grouped for column sensing. The number of row
and column electrodes is determined by the size and resolution of
the touch panel. In this example, the top-right row electrode is
x.sub.n,m. Each row electrode x.sub.0,0-x.sub.n,m, of touch panel
20 is electrically connected to interconnect area 21 and
corresponding processing circuitry/software by a conductive trace
22. Each column electrode y.sub.0-y.sub.n is also electrically
connected to interconnect area 21 and corresponding processing
circuitry/software, either directly or by a conductive trace. The
conductive traces 22 are preferably formed of the same transparent
conductive material (multilayer conductive transparent coating 41)
as the row and column electrodes (e.g., same material as at least
row electrodes x.sub.0,0, x.sub.1,0, x.sub.2,0, etc.). Thus, in
certain example embodiments, the matrix of row and column
electrodes x, y and corresponding traces 22 can be formed on the
substrate (e.g., glass substrate) 40 by forming the coating 41
(e.g., by sputter-depositing the coating 41) on the substrate 40
and by performing only one (or maximum two) photolithography and/or
other patterning process in order to pattern the coating 41 into
the conductive electrodes x, y and/or conductive traces 22. In
certain example embodiments, the silver-inclusive coating (e.g.,
see example coating 41 in FIGS. 4(a)-(h)) is sputter deposited on
the glass substrate 40 and is then subjected to photolithography
and/or laser patterning to pattern the silver-inclusive coating 41
into traces 22, row electrodes x.sub.0,0, x.sub.1,0, x.sub.2,0,
x.sub.0,1, x.sub.,0, 2, x.sub.0,3, etc. through x.sub.n,m, and
column electrodes y.sub.0-y.sub.0. Because the row electrodes
x.sub.0,0-x.sub.n,m, column electrodes y.sub.0-y.sub.n, and traces
22 do not overlap as viewed from above/below, the row electrodes
x.sub.0,0-x.sub.n,m, column electrodes y.sub.0-y.sub.n, and traces
22 may be formed on the same plane parallel (or substantially
parallel) to glass substrate 40 on which the electrodes and traces
are formed. And no insulating layer between electrodes x and y is
needed in certain example embodiments. Significant portions of
traces 22 may also be parallel (or substantially parallel) to the
column electrodes in the plane parallel (or substantially parallel)
to the substrate 40. Accordingly, touch panel 20 may be made via a
smaller number of photolithography or laser patterning steps while
achieving traces that achieve sufficient transparency and
conductivity, thereby reducing production costs and resulting in a
more efficient touch panel for use in a display assembly or the
like.
[0048] FIG. 2(b) illustrates a schematic representation of
circuitry for the touch panel 20 illustrated in FIG. 2(a),
according to exemplary embodiments. In touch panel 20, there is a
capacitance between each row electrode and the adjacent column
electrode (for example, between row electrode x.sub.0,0 and column
electrode y.sub.0). This capacitance can be measured by applying a
voltage to a column electrode (for example, column electrode
y.sub.0) and measuring the voltage of an adjacent row electrode
(for example, row electrode x.sub.0,0). When a user brings a finger
or conductive stylus close to touch panel 20, changes in the local
electrostatic field reduce the mutual capacitance. Thus, one may be
considered a transmit electrode y.sub.0 and the other a receive
electrode x.sub.0,0. The capacitance change at individual points on
the surface can be measured by measuring each pair of row
electrodes and column electrodes in sequence. The traces 22 of each
row electrode in the same row (for example, the traces 22 of row
electrodes x.sub.0,0, x.sub.1,0, x.sub.2,0, etc., through x.sub.n,0
of row 0) may be electrically connected together (as shown in FIG.
2(b)). The interconnection of the first row segments to each other,
second row segments to each other, etc., may be made on a flexible
circuit(s) attached at the periphery of the touch panel in the
interconnection area, so that no cross-overs are needed on the
glass substrate 40. In that instance, a voltage is applied to a
column electrode and the voltage of each row is measured in
sequence before the process is repeated with a voltage applied to
another column. Alternatively, each trace 22 may be connected to
signal processor 25 and the voltage of each trace 22 may be
measured individually. The same capacitance may be measured by
applying a voltage to a row electrode and measuring the voltage on
an adjacent column electrode rather than applying a voltage to a
column electrode and measuring the voltage of an adjacent row
electrode. Signal processing (for example, applying and measuring
voltages, measuring the capacitance between adjacent electrodes,
measuring changes in capacitance over time, outputting signals in
response to user inputs, etc.) may be performed by signal processor
25. Signal processor 25 may be one or more hardware processors, may
include volatile or non-volatile memory, and may include
computer-readable instructions for executing the signal processing.
Signal processor 25 is electrically connected to the column
electrodes y.sub.0-y.sub.n and electrically connected to the row
electrodes x.sub.0,0-x.sub.n,m, through the traces 22. Signal
processor 25 may or may not be located on the same plane as row
electrodes x.sub.0,0-x.sub.n,m, column electrodes y.sub.0-y.sub.n,
and traces 22 (for example, in interconnect area 21 of FIG.
2(a)).
[0049] FIG. 3(a) illustrates a top or bottom plan layout of a
projected capacitive touch panel according to another example
embodiment, that includes the coating 41 of any of FIGS. 4(a)-(h),
6, 7, and/or 8 patterned to form the conductive electrode(s) x, y
and/or conductive trace(s) 22. Referring to FIG. 3(a), touch panel
30 is similar to touch panel 20 of FIG. 2(a), except that touch
panel 30 is divided into upper section 31 and lower section 32,
each of which includes a matrix of electrodes x, y including n
columns and m rows. For example, row 0 of upper section 31 includes
row electrodes x.sub.0,0, x.sub.1,0, x.sub.2,0, etc., through
x.sub.n,0. Upper section 31 also includes column electrodes
y.sub.0, y.sub.1, y.sub.2, etc., through y.sub.n. Likewise, lower
section 32 would also include row electrodes, and column electrodes
y.sub.0-y.sub.n that may be electrically separate from the column
electrodes y.sub.0-y.sub.n of the upper section 31. Thus, lower
section 32 also includes a matrix of row electrodes including n
columns and m rows, and n column electrodes. Lower section 32 may
have more or less rows than upper section 31 in different example
embodiments. The number of row and column electrodes of touch panel
30 is determined by the size and resolution of the touch panel.
Each column electrode of upper section 31 is electrically connected
to interconnect area 21, and each row electrode of upper section 31
is electrically connected to interconnect area 21 by a trace 22. As
with the FIG. 2 embodiment, traces may or may not be used for
connecting the column electrodes of upper section 31 to the
interconnect area. Each column electrode of lower section 32 is
electrically connected to interconnect area 21' and each row
electrode of lower section 32 is electrically connected to
interconnect area 21' by a trace 22. Again, traces may or may not
be used for connecting the column electrodes of the lower section
32 to the interconnect area 21'. Still referring to FIG. 3(a),
touch panel 30 is similar to touch panel 20 in that there is a
capacitance between each row electrode and the adjacent column
electrode which may be measured by applying a voltage to a column
electrode and measuring the voltage of an adjacent row electrode
(or, alternatively, by applying a voltage to a row electrode and
measuring the voltage of an adjacent column electrode). When a user
brings a finger or conductive stylus close to touch panel 30,
changes in the local electrostatic field reduce the mutual
capacitance. The capacitance change at individual points on the
surface can be measured by measuring the mutual capacitance of each
pair of row electrodes and column electrodes in sequence.
[0050] FIGS. 3(b) and 3(c) illustrate top or bottom plan layouts of
a portion of a projected capacitive touch panel according to
further example embodiments, that includes the coating 41 of any of
FIGS. 4(a)-(h), 6, 7, and/or 8 patterned to form the conductive
electrode(s) x, y and/or conductive trace(s) 22. An example
electrode configuration of a pro-cap sensor may utilize a single
transparent conductive coating 41 patterned into the form of
parallel electrode stripes as shown in either FIG. 3(b) of FIG.
3(c). In FIG. 3(b), the electrodes stripes are fairly straight,
while in FIG. 3(c) one or more of the electrode stripes may have a
zig-zag shape. These electrode stripes correspond to the
alternating receiving (R) and transmitting (T) electrodes connected
to a driver. The driver charges the transmit/transmitting
electrodes (T) with alternating current. The position of a
receive/receiving electrode (R) allows the detection of the X
coordinate upon touch from a finger, while the output voltage from
the transmitting electrode (T) allows the detection of the Y
coordinate, thus enabling the positional identification of a single
touch or multiple touches. It is desirable to have a set of
receiving electrodes (R) made from a material with a low sheet
resistance (R.sub.s), such as silver (e.g., lower R.sub.s than ITO
of a similar thickness), so that the voltage drop along each
electrode is minimal/reduced. It is desired, at the same time, that
the transmitting electrodes (T) have a higher sheet resistance
(reduced conductivity), compared to pure silver in certain coatings
so there is a substantial voltage gradient along each transmit
electrode to increase the noise-to-signal ratio. Thus, there are
competing interests with respect to the sheet resistance of the two
sets of electrodes, namely receive electrodes (R) and transmit
electrodes (T). For the receive and transmit electrodes,
silver-based layer 46 in a coating 41 as a substitute for the
commonly used indium-tin-oxide (ITO) is desirable, for a much more
conductive electrode material. The silver layer 46 may be
sandwiched between at least two dielectric layers, and may use an
underlayer (e.g., crystalline zinc oxide 44, which may be doped
with Al for example) to attain a higher silver conductivity due to
a better crystalline orientation. In this case, the low sheet
resistance of silver allows large formats of the touch screen, but
may sometimes be too low for effective use of transmitting
electrodes. To address this discrepancy, one of the transmitting
electrode(s) architectures may use a zigzag pattern as shown in
FIG. 3(c) to reduce the width of each electrode, while increasing
its effective length and, thus increasing its sheet resistance.
Such a reduction in width, however, makes the transmitting
electrode prone to defects, such as scratches, particulates,
macro-inclusions, etc. Thus, in certain example embodiments of this
invention, embodiments are provided reducing the conductivity of
the silver layer 46 to make it conductive enough for the receiving
electrodes and, at the same time, resistive enough for an effective
use of the transmitting electrodes. Thus, the same silver structure
may be used for conductive layer(s) 46 for both the transmit and
receive electrodes in certain example embodiments. The increase in
sheet resistance of the silver layer 46 may be done by one of the
following methods or by their combination: (a) doping the
conductive silver layer 46 with an impurity such as one or more of
Zn, Pt, Pd, Ti, Al, or a combination thereof, and/or (b) replacing
crystalline zinc oxide directly under the conductive silver 46 with
a suitable non-crystalline dielectric [e.g., silicon oxide (e.g.,
SiO.sub.2), silicon oxynitride, silicon nitride (e.g.,
Si.sub.3N.sub.4), titanium oxide (e.g., TiO.sub.2), or zinc
stannate], amorphous semiconductor (e.g., a-Si), or metal alloy
(e.g., NiCr, NiCrMo, or the like). Doping with some impurities may
help make the silver layer 46 more resistive to oxidation and/or
environmental degradation.
[0051] Because the row electrodes and column electrodes x, y
illustrated in FIGS. 3(a)-3(c) do not overlap in certain example
embodiments, the row electrodes and column electrodes may (or may
not) be formed on the same plane by patterned transparent
conductive coating 41, in the manner explained above in connection
with FIG. 2. Accordingly, electrode structure x, y for the touch
panel 30 of any of FIGS. 3(a)-3(c) may be thin in nature and may be
patterned with one process (for example, one photolithography
process or one laser patterning process) which reduces the
production cost of the projected capacitive touch panel.
[0052] However, in certain example embodiments, different silver
structure may be used for receive electrodes compared to that used
for transmit electrodes of the touch panel. This is applicable to
any embodiment herein. As explained herein, referring to FIGS.
3(b)-3(g) for example, it may be desirable to have a set of
receiving electrodes (R) made from a material with a low sheet
resistance (R.sub.s) and low resistivity, such as silver (e.g.,
lower R.sub.s and lower resistivity than ITO of a similar
thickness), so that the voltage drop along each electrode is
minimal/reduced, while at the same time it is desirable for the
transmitting electrodes (T) to have a higher sheet resistance and
higher resistivity (reduced conductivity), compared to pure silver
in certain coatings, so there is a substantial voltage gradient
along each transmit electrode (T) to increase the noise-to-signal
ratio. Thus, there are competing interests with respect to the
sheet resistance of the two sets of electrodes, namely receive
electrodes (R) and transmit electrodes (T). Therefore, in certain
example embodiments, different electrodes 41 of the touch panel may
be designed to have different sheet resistances.
[0053] For example, referring to any of FIGS. 3(b)-3(g) for
example, transmit electrodes (T) may have higher sheet resistance
than receive electrodes (R) in certain example embodiments. For
example, transmit electrodes (T) may have a sheet resistance of
from about 15-50 ohms/square, more preferably from about 20-50
ohms/square, and most preferably from about 20-40 ohms/square. And
receive electrodes (R) may have a sheet resistance of from about
1-14 ohms/square, more preferably from about 2-12 ohms/square, and
most preferably from about 2-10 ohms/square. In certain example
embodiments, the transmit electrodes (T) may have a sheet
resistance at least 1 ohm/square higher, more preferably at least 5
ohms/square (more preferably at least 10, 15 or 20 ohms/square)
higher, than the sheet resistance of the receive electrodes (R).
This may also apply to any other embodiment herein, and may apply
to some or all transmit and receive electrodes. For example, one,
some, or all of the transmit electrodes (T) in any embodiment
herein may be made up of a multi-layer coating 41 including a
silver layer 46 that has higher sheet resistance (and thus lower
conductivity) compared to pure silver in certain types of coatings,
with the higher sheet resistance of the silver-based layer 46 for
transmit electrodes (T) being achieved by doping the silver with an
impurity such as one or more of Zn, Pt, Pd, Ti, Al or the like,
and/or by replacing crystalline zinc oxide directly under and
contacting the silver with another material such as a suitable
non-crystalline dielectric, amorphous semiconductor, or metal alloy
(e.g., NiCr) in order to increase the silver's resistance as
discussed above. The receive electrodes (R) may be designed to have
a lower sheet resistance than the transmit electrodes (T), such as
by not doping the silver based layer 46 in the coating 41 of the
receive electrodes and/or by providing them on and contacting a
crystalline or substantially crystalline layer of or including zinc
oxide 44 which may optionally be doped with from about 1-10%, more
preferably from about 1-5% aluminum.
[0054] In other example embodiments, the different resistance of
the transmit (T) and receive (R) electrodes may be achieved may
making the silver-based conductive layer 46 of these respective
electrodes at different thicknesses (with the same or different
structure/material) in order to adjust the respective sheet
resistance of each electrode based on thickness. Different
thicknesses for the silver based layers 46 of the different
electrodes (T) and (R) may (but need not) be used in combination
with other techniques, such as doping and adjustment of the layer
directly under the silver discussed herein.
[0055] FIG. 3(d) illustrates an example embodiment where the
transmit (T) and receive (R) electrodes, with their different
respective sheet resistances, are parallel and overlap one another.
Thus, the (T) and (R) electrodes are on different planes in the
FIG. 3(d) embodiment. In the FIG. 3(d) embodiment, the (T) and (R)
electrodes may be formed using different multi-layer coatings 41,
or alternatively a single multi-layer coating 41 with two different
silver based layers 46 having different resistance may be used to
form overlapping (T) and (R) electrodes. In embodiments where the
(T) and (R) electrodes are formed using a single multi-layer
coating 41 with two different silver based layers 46, the double
silver multi-layer coating may be formed, for example, by repeating
the layer stacks of any of FIGS. 4(a)-4(h) on top of the
illustrated coating so as to provide a coating including two silver
based layers 46. For instance, referring to FIG. 4(a), a double
silver coating 41 could be made up of the following layers moving
outwardly from the glass substrate 40:
40/43/44/46/47/48/49/50/43/44/46/47/48/49/50. Referring to FIG.
4(f), a double silver coating 41 may be formed of the following
layers moving away from the glass substrate 40:
40/61/101/46/47/50/61/101/46/47/50, as another example. In each of
these example double silver coatings, the bottom conductive silver
based layer 46 may be used for one of the electrodes (transmit or
receive), and the top silver based layer 46 may be used for the
other of the electrodes--this is particularly useful in embodiments
such as FIG. 3(d) where the T and R electrodes are parallel,
overlap, and are directly over each other.
[0056] FIG. 3(e) illustrates an example embodiment where the
transmit (T) and receive (R) electrodes, with their different
respective sheet resistances, are parallel and do not overlap one
another. Thus, the (T) and (R) electrodes may be in the same plane,
or on different planes, in the FIG. 3(d) embodiment. In the FIG.
3(e) embodiment, since the transmit and receive electrodes do not
overlap, the (T) and (R) electrodes may be formed using different
multi-layer coatings 41. In FIGS. 3(d)-(e) for example, the
transmit and receive electrodes may generally be of the same shape
in certain example embodiments, and may be formed via the same or
different patterning steps. While the transmit and receive
electrodes are parallel or substantially parallel to each other in
FIGS. 3(d)-(e), in other example embodiments the transmit and
receive electrodes of the touch panel may be perpendicular to each
other and overlap each other.
[0057] FIG. 3(f) is a top view of part of a capacitive touch panel
electrode arrangement according to an example embodiment of this
invention, where transmit electrodes (T) and receive electrodes (R)
overlap and are substantially orthogonal to one another on
different planes. And FIG. 3(g) is a cross sectional view of the
capacitive touch panel electrode arrangement of FIG. 3(f) along
sectional line a-a', where transmit electrodes and receive
electrodes overlap and are substantially orthogonal to one another
on different planes. The supporting glass substrate 40, that
supports the electrodes, is not shown in FIGS. 3(f)-(g) for
purposes of simplicity.
[0058] Referring to FIGS. 3(f)-3(g), for example, the transmit
electrodes (T) and the receive electrodes (R) may be formed from
different silver based layers 46 in the same multi-layer coating 41
in certain example embodiments of this invention (e.g., see FIG.
4(h) or double silver coating stacks discussed herein with respect
to any of FIGS. 4(a)-(g)). For example, the transmit electrodes (T)
in FIGS. 3(f)-(g) may be formed between the supporting glass
substrate 40 and the overlying receive electrodes (R), and the
conductors of the transmit electrodes (T) may be formed using the
lower silver based layer 46 in the double silver coating of FIG.
4(h) whereas the conductors of the overlying receive electrodes (R)
may be formed using the upper silver based layer 46 in the double
silver coating of FIG. 4(h). The double silver coating of FIG. 4(h)
is used for purposes of example, and other double silver coatings
may be used for this purpose, whether disclosed herein or not.
Thus, in such embodiments, the transmit electrodes (T) and the
receive electrodes (R) may be formed from different silver based
layers 46 of the same multi-layer coating 41. In such example
embodiments, the transmit electrodes (T) and the receive electrodes
(R) are patterned in different steps so as to be patterned into
different forms--for example in FIG. 3(f) the transmit electrodes
(T) are patterned into column electrodes extending in the y
direction while the receive electrodes (R) are patterned into row
electrodes extending in the x direction. For example, the transmit
electrodes (T) may be patterned into column electrodes extending in
the y direction by laser scribing/ablation in a first patterning
step, and the receive electrodes (R) may be patterned into row
electrodes extending in the x direction by laser scribing/ablation
in a second patterning step. Laser scribing, for example, is used
to cut through at least the desired silver based layer(s) during
patterning.
[0059] Mutual capacitance sensors, such as those discussed herein,
use a principle of charging at least some electrodes with
alternating current and interpreting a change in their capacitance
as a touch. Herein, it is discussed to use thin silver (Ag) as a
substitute for the ITO, at least because silver has a superior
conductivity compared to the ITO as well as a high visible optical
transmission. Silver, however, is more susceptible to damage than
ITO when exposed to certain chemicals. Thus, it is sometimes
desirable to pattern silver using laser patterning techniques, as
opposed to conventional photolithography. In certain example
embodiments, such as shown in FIGS. 3(f)-(g), it would be desirable
to arrange respective sets of transmitting (T) and receiving (R)
electrodes of a silver-based mutual capacitance touch sensor in an
X-Y configuration using a patterning process on a completed layer
stack (e.g., see the multi-layer coating of FIG. 4(h)), preferably
by laser scribing. An issue is that to define the two sets of X-Y
electrodes--transmitting and receiving--provided in two parallel
planes as an orthogonal matrix faces a challenge of scribing the
electrodes in the X direction without damaging the underlying
electrodes oriented along the Y direction, or vice versa. Thus, in
an example embodiment, various wavelengths are used to pattern the
two sets of electrodes (T and R) independently. In another example
embodiment, the two sets of electrodes are patterned from different
sides of the supporting glass substrate 40 either using the same
wavelength or using at least two different wavelengths.
[0060] In certain example embodiments, different electrodes of the
touch panel may be formed by different silver based layers 46 of
the same or different multi-layer coatings. In patterning the
electrodes (T) and (R), different laser scribing wavelengths may be
used to pattern different respective silver based layers 46, of the
same or different multi-layer coating(s) 41, in certain example
embodiments. For example, when first (e.g., transmit) and second
(e.g., receive) electrodes of the touch panel overlap each other
(e.g., see FIGS. 3(f)-(g)), a first laser scribing wavelength may
be used when patterning the first silver based layer 46 into the
first electrode(s), and a second laser scribing wavelength may be
used when patterning the second silver based layer 46 into the
second electrode(s). For example, transmit electrodes (T) in FIGS.
3(f)-(g) may be laser patterned using a first wavelength(s), and
receive electrodes (R) in FIGS. 3(f)-(g) may be laser patterned
using a different second wavelength(s). Advantageously, the use of
the different wavelengths reduces damage to electrode(s) not
intended to be patterned in a given procedure.
[0061] In certain example embodiments, when different electrodes of
the touch panel may be formed by different silver based layers 46
of the same or different multi-layer coatings 41, a first set of
electrodes (e.g., T) may be patterned by laser scribing from a
first side of the supporting glass substrate 40, whereas a second
set of electrodes (e.g., R) may be patterned by laser scribing from
an opposite second side of the supporting glass substrate 40. Thus,
since the transmit and receive electrodes are on the same side of
the glass substrate 40, one of the two laser patterning procedures
is performed through the supporting glass substrate 40. For
example, referring to FIGS. 3(f)-(g) and 4(h), transmit electrodes
(T) may be laser patterned from a first side of the supporting
glass substrate 40, whereas receive electrodes (R) may be laser
patterned form the opposite second side of the supporting glass
substrate 40 so that the laser beam for patterning the receive
electrodes (R) passes through the glass substrate 40.
Advantageously, this technique reduces damage to electrodes not
intended to be patterned in a given laser patterning procedure. The
embodiment involving laser patterning of different electrodes from
opposite sides of the supporting glass substrate may, or may not,
be used in combination with the embodiment using different
wavelengths to pattern different electrodes.
[0062] As explained in connection with FIGS. 14(a)-14(b), it has
been found that the upper Ag layer 46 in a double silver coating
such as shown in FIG. 4(h) is more optically absorbent in the
wavelength range of 800-900 nm, while the maximum absorption of the
bottom silver layer 46 is shifted to shorter wavelengths.
Optimizing the double-silver layer stack allows a better
differentiation between the absorption maxima of the two silver
layers 46. FIG. 14(b) shows a much greater difference in optical
absorption between the top and the bottom silver layers of the FIG.
4(h) coating stack at about 770 nm and much less difference at
about 580 nm. This differentiation allows a selective laser
scribing of the two conductive silver based layers 46 either from
one side (top of the stack, for instance) or from both sides--e.g.,
the stack side for the top silver and the glass side for the bottom
silver layer.
[0063] A capacitive touch sensor comprising two Ag separated by at
least one non-Ag layer and sandwiched between at least two
dielectric layers supported by a substrate and patterned to form
two independent sets of transmitting and receiving electrodes
substantially parallel to each other and to the substrate, wherein
the receiving and transmitting electrodes are formed in the
different Ag layers and the two sets of electrodes are orthogonal
to each other; the two sets of electrodes are formed by scribing
using a laser or lasers with at least two different wavelengths
selected to be absorbed preferentially by each of the Ag layers.
For example, the bottom silver based layer 46 in the FIG. 4(h)
coating may be laser scribed using a laser wavelength of from about
400-620 nm (more preferably from about 500-600 nm) in order to
pattern that layer 46 into the transmit electrodes (T) shown in
FIGS. 3(f)-(g) or any other embodiment herein. The laser patterning
of the bottom silver based layer 46 in the FIG. 4(h) to form the
transmit electrodes (T) shown in FIGS. 3(f)-(g) may be done by
directing the laser beam through the glass substrate 40. On the
other hand, the upper silver based layer 46 in the FIG. 4(h)
coating may be laser scribed using a laser wavelength of from about
630-1200 nm (more preferably from about 650-1100 nm, and most
preferably from about 700-1000 nm) in order to pattern that layer
46 into the receive electrodes (R) shown in FIGS. 3(f)-(g) or any
other embodiment herein. The laser patterning of the upper silver
based layer 46 in the FIG. 4(h) to form the overlying receive
electrodes (R) shown in FIGS. 3(f)-(g) may be done by directing the
laser beam from above the coating 41 so that the laser beam reaches
the silver layer 46 before the glass substrate 40. The use of the
different wavelength can be advantageous in reducing damage to the
silver layer not intended to be patterned in a given patterning
procedure, as can the use of lasers from opposite sides of the
glass substrate. In certain example embodiments, each of the two
resulting electrodes may have a sheet resistance of from about 2-40
ohms/square, more preferably from about 2-20 ohms/square.
[0064] As one of ordinary skill in the art would recognize, touch
panels 20 and 30 described are not limited to the orientations
described above and shown in FIGS. 2-3. In other words, the terms
"row," "column" "x-axis," and y-axis" as used in this application
are not meant to imply a specific direction. Touch panel 20 of FIG.
2(a), for example, may be modified or rotated such that
interconnect area 21 is located in any part of touch panel 20.
[0065] In the FIG. 2-3 embodiments, narrow transparent conductive
traces (e.g., 22) may be routed to electrically connect electrodes
to interconnect area 21 (and interconnect area 21'). Because of the
large resistance of the narrow ITO traces, narrow ITO traces may
only been used in small touch panels, such as for smart phones. To
use one of the layouts illustrated in FIGS. 2(a) and 3 on larger
touch panels (for example, measuring more than 10 inches
diagonally) or otherwise, a transparent conductive coating 41 with
lower sheet resistance (compared to ITO at like thickness) is used.
The silver inclusive coating 41 shown in FIG. 4 (any of FIGS.
4(a)-(h)) for use in forming the electrodes and traces of FIGS. 2-3
is advantageous in this respect because it has a much lower sheet
resistance (and thus more conductivity) than typical conventional
ITO traces/electrodes.
[0066] Examples of multilayer silver-inclusive transparent
conductive coatings (TCC) 41 with low sheet resistance, for forming
any and/or all of the conductive electrodes and/or conductive
traces of FIGS. 2-3 are illustrated in FIG. 4 (FIGS. 4(a)-4(h))
according to exemplary embodiments of this invention. The low sheet
resistance and high transparency of the TCC 41 allow the TCC to
form the long narrow traces 22 as well as the row and column
electrodes x, y and/or transmit/receive electrodes for example.
[0067] Referring to FIG. 4(a), multilayer transparent conductive
coating 41 in an example embodiment is provided, either directly or
indirectly, on substrate 40. Substrate 40 may be, for example,
glass. In alternative embodiments discussed below, an
anti-reflective (AR) coating may be provided between the substrate
40 and the coating 41. Coating 41 may include, for example, a
dielectric high index layer 43 of or including a material such as
titanium oxide or niobium oxide, which may include titanium oxide
(e.g., TiO.sub.2 or other suitable stoichiometry); a dielectric
layer of or including zinc oxide 44, optionally doped with
aluminum, to be in contact with the silver-based layer; a
silver-based conductive layer 46 on and directly contacting the
zinc oxide based layer 44; an upper contact layer 47 including
nickel and/or chromium or other suitable material which may be
oxided and/or nitrided, that is over and contacting the
silver-based conductive layer 46; a dielectric high index layer 48
of or including a material such as titanium oxide or niobium oxide,
which may include titanium oxide (e.g., TiO.sub.2 or other suitable
stoichiometry); a dielectric layer 49 of or including tin oxide
(e.g., SnO.sub.2); and a dielectric layer 50 of or including
silicon nitride and/or silicon oxynitride which may be doped with
from 1-8% Al for example. Each of the layers in the coating 41 is
designed to be substantially transparent (e.g., at least 70% or at
least 80% transparent) to visible light. The dielectric high index
layer 43 may be fully oxidized or sub-stoichiometric in different
example embodiments. The silver layer 46 may or may not be doped
with other materials (e.g., Pd, Pt, Zn, Ti and/or Al) in certain
example embodiments, as discussed herein. Instead, of zinc oxide,
layer 44 may be of or include Upper contact layer 47 may be of or
include materials such as NiCr, NiCrO.sub.x, NiCrN.sub.x,
NiCrON.sub.x, NiCrMo, MiCrMoO.sub.x, TiO.sub.x, or the like. The
zinc oxide of layer 44 directly under the conductive silver 46 may
be replaced with an amorphous or substantially amorphous dielectric
[e.g., silicon oxide (e.g., SiO.sub.2), silicon oxynitride, silicon
nitride (e.g., Si.sub.3N.sub.4), titanium oxide (e.g., TiO.sub.2),
or zinc stannate], an amorphous semiconductor (e.g., a-Si), or a
metal alloy (e.g., NiCr, NiCrMo, or the like) as layer 44, in order
to adjust the conductivity of the silver based layer 46 as
discussed herein.
[0068] The coating 41 is designed to achieve good conductivity via
conductive silver based layer 46, while optionally at the same time
to reduce visibility by more closely matching is visible
reflectance (glass side and/or film side visible reflectance) to
the visible reflectance of the supporting substrate 40. Note that
the glass side visible reflectance is measured from the side of the
coated glass substrate opposite the coating, whereas the film side
visible reflectance is measured from the side of the coated glass
substrate having the coating. Substantial matching of the visible
reflectance of the coating 41 and the visible reflectance of the
supporting glass substrate 40 reduces visibility of the electrodes
and traces formed of the coating material 41. Surprisingly and
unexpectedly, it has been found that adjusting certain dielectric
thicknesses of the FIG. 4(a) coating can surprising improve
(reduce) the visibility of the coating 41 and thus make the
patterned electrodes and traces of the touch panel less visible to
users and therefore more aesthetically pleasing.
[0069] While various thicknesses and materials may be used in
layers in different embodiments of this invention, example
thicknesses and materials for the respective sputter-deposited
layers of coating 41 on the glass substrate 40 in the FIG. 4(a)
embodiment are as follows, from the glass substrate outwardly:
TABLE-US-00001 TABLE 1 FIG. 4(a) Transparent Conductive Coating
Preferred More Preferred Example Ref Material Thickness (.ANG.)
Thickness (.ANG.) Thickness (.ANG.) 43 TiO.sub.x 130-185 150-185
177 44 ZnO 50-140 60-100 83 46 Ag 90-160 115-140 124 47 NiCrOx
15-50 15-30 20 48 TiO.sub.x 10-60 15-35 23 49 SnO.sub.2 80-220
110-150 130 50 Si.sub.xN.sub.y 300-400 300-320 305
[0070] It is noted that the above materials for coating 41 in the
FIG. 4(a) embodiment are exemplary, so that other material(s) may
instead be used and certain layers may be omitted in certain
example embodiments. This coating has both low sheet resistance,
and has layers designed to reduce visibility of the coating 41 on
the supporting glass substrate 40. In certain exemplary
embodiments, glass substrate 40 with coating 41 thereon may be heat
treated (e.g., thermally tempered), e.g., after coating, or
chemically strengthened before coating.
[0071] In FIGS. 4(a)-(h), silver-inclusive coating 41 is
inexpensive, has a low sheet resistance (preferably less than 40
ohms/square, more preferably less than 20 ohms/square, even more
preferably less than about 15 or 10 ohms/square) and maintains high
visible transmittance (preferably at least 60%, more preferably at
least 70%, more preferably at least 80%, and most preferably at
least 84%). The coating 41 is preferably deposited on substantially
the entirety of the major surface of the glass substrate 40, and
then patterned to form the electrodes and/or traces. For example,
the example display assembly shown in FIG. 7 includes a touch panel
(20 or 30 or 50) mounted on a liquid crystal display panel
(100-300). In the FIG. 7 embodiment, one or more of the row
electrodes, column electrodes, and traces may be formed from
coating 41 on the surface of the glass substrate 40 opposite the
finger, and the touch panel (20, 30 or 50) may be adhered to the
LCD panel via an index-matching adhesive layer 85. The LCD panel
includes first and second substrates (e.g., glass substrates) 100,
200 with a liquid crystal layer 300 provided therebetween. In order
to form a touchscreen, the touch panel 20, 30 may optionally be
mounted on the LCD panel with a small air gap or bonded to the
display with an index-matching adhesive 85. Thus, reference numeral
85 in FIG. 7 represents either an air gap or an index matching
adhesive between the display and the touch panel. It is noted that
for the measurements taken for FIGS. 5-6 and 8(a)-(b), an air gap
85 was assumed so that the coating 41 was adjacent an air gap 85.
In air gap embodiments, the periphery of the substrate 40
supporting the coating 41 may be bonded to the liquid crystal panel
via adhesive or any other suitable type of edge seal material.
[0072] The pixel pitch for projected capacitive touch panels may,
for example, be in the range of from about 6 to 7 mm. Touch
location can be determined more accurately for example, to about 1
mm, by signal processing and interpolation. If the line
width/spacing for the traces 22 is approximately 10 .mu.m to 20
.mu.m, it can be calculated that a projected capacitive touch panel
of at least 20 inches (measured diagonally) is possible for a TCC
sheet resistance of about 4 ohms/square. Further optimization of
the routing, signal processing and/or noise suppression allows for
production of even larger touch panels (for example, up to 40 or 50
inches diagonally). This invention is also applicable to smaller
touch panels in certain example embodiments.
Example 1 Vs. Comparative Example (CE)
[0073] Surprisingly and unexpectedly, it has been found that
adjusting certain dielectric thicknesses of the FIG. 4(a) coating
can surprisingly reduce the visibility of the coating 41 on the
supporting substrate 40, and thus make the electrodes and traces of
the touch panel less visible to users and therefore the overall
panel more aesthetically pleasing. This is evidenced, for example,
by the comparison below between a Comparative Example (CE) and
Example 1 of this invention, where the coatings include from the
glass substrate outwardly:
TABLE-US-00002 TABLE 2 Comparative Example (CE) vs. Example 1
Comparative Example (CE) Example 1 Ref Material Thickness (.ANG.)
Thickness (.ANG.) 43 TiO.sub.x 194 177 44 ZnO 83 83 46 Ag 124 124
47 NiCrOx 20 20 48 TiO.sub.x 23 23 49 SnO.sub.2 30 130 50
Si.sub.xN.sub.y 295 305
[0074] It can be seen from Table 2 above that the only difference
between Example 1 according to this invention and the Comparative
Example (CE) are the thicknesses of the dielectric layers 43 and
50. Surprisingly and unexpectedly, it has been found that adjusting
the thicknesses of layers 43 and 50 the coating can surprising
reduce the visibility of the coating 41 areas on the supporting
glass substrate 40 by more closely matching the visible reflectance
(e.g., glass side visible reflectance) of the coating 41 on the
glass substrate to the visible reflection of the glass substrate 40
alone, and thus make the electrodes and traces of the touch panel
less visible to users and therefore more aesthetically pleasing.
This is shown in FIGS. 5-6 and also in the tables below.
[0075] FIG. 5 is a percent transmission/reflectance vs. wavelength
(nm) graph illustrating the visible transmission (TR) percentage
and glass side visible reflection (BRA) percentage of the
Comparative Example (CE) coating on a glass substrate, compared to
those values for the glass substrate alone (Glass-TR, Glass-BRA).
Note that FIG. 5 includes the visible spectrum, as well as some
wavelength outside the visible spectrum. The line plot with the "x"
through it in FIG. 5 is the glass side visible reflection of the CE
coating on the glass substrate 40 (i.e., reflection taken from the
side of the finger in FIG. 7), and the line plot in FIG. 5 with the
triangle marking through it is the visible reflection of the glass
substrate 40 alone in areas where the coating 41 is not present.
The difference between these two lines is relevant, because it
shows the difference in glass side visible reflection between: (a)
areas of the glass substrate 40 where the CE coating is not present
(i.e., in non-electrode and non-trace areas), and (b) areas of the
glass substrate 40 where the CE coating is present (i.e., in
electrode and trace areas). Thus, the larger the difference between
these two lines (the bottom two lines in the FIG. 5 graph), the
more visible the electrodes and traces are to a viewer from the
point of view on the finger side in FIG. 7. It can be seen in FIG.
5 that there is a significant gap (more than 2.0 difference in
reflectance percentage) between these two lines around the visible
wavelength 600 nm (including on both sides thereof), meaning that
the electrodes and traces on a touch panel made of the CE material
will be very visible which can render a touch panel or the like
aesthetically non-pleasing.
[0076] In contrast, FIG. 6 is a percent visible
transmission/reflectance vs. wavelength (nm) graph illustrating the
visible transmission (CGN-TR or TR) and glass side visible
reflection (CGN-BRA or BRA) of the Example 1 coating of FIG. 4(a)
according to an example embodiment of this invention on a glass
substrate, demonstrating that it is transparent to visible light
and has glass side visible reflectance more closely matched to that
of the glass substrate compared to the CE in FIG. 5. FIG. 6, like
FIG. 5, also illustrates the visible transmission (Glass-TR) and
visible reflectance (Glass-BRA) for the glass substrate alone in
areas without the coating on it. The line plot with the "x" through
it in FIG. 6 is the glass side visible reflection of the Example 1
coating 41 on the glass substrate 40, and the line plot in FIG. 6
with the triangular marking through it is the visible reflection of
the glass substrate 40 alone without the coating 41 on it. The
difference between these two lines is relevant, because it shows
the difference in visible reflection (from the point of view of the
finger in FIG. 7) between (a) areas of the glass substrate and
touch panel where coating 41 is not present (i.e., in non-electrode
and non-trace areas), and (b) areas of the glass substrate and
touch panel where the coating 41 is present (i.e., in electrode and
trace areas). Thus, the larger the difference between these two
lines (the bottom two lines in the FIG. 6 graph), the more visible
the electrodes and traces are to a viewer. And the smaller the
difference between these two lines (the bottom two lines in the
FIG. 6 graph), the less visible the electrodes and traces are to a
viewer. Comparing FIGS. 5 and 6 to each other, it can be seen that
in FIG. 6 that there is a much smaller gap (if any) between these
two lines for the visible wavelengths from about 550 nm to about
650 nm compared to the larger gap for the CE in FIG. 5, meaning
that the electrodes and traces on a touch panel made of the Example
1 material (FIG. 6) will be much less visible (compared to the CE
material of FIG. 5) which renders the touch panel more
aesthetically pleasing. In other words, compared to the CE, Example
1 more closely matches the glass side visible reflectance of the
coating 41 on the glass substrate 40 to the visible reflection of
the glass substrate 40 in areas where the coating is not present,
and thus make the electrodes and traces of the touch panel less
visible to users and therefore more aesthetically pleasing.
[0077] The table below shows optical differences between the
Comparative Example (CE) and Example 1, where at 550 nm TR is
visible transmission, RA is film side visible reflectance which is
measured viewing the glass/coating combination from the coating
side, and BRA is glass side visible reflectance which is measured
viewing the glass/coating combination from the glass side. As will
be recognized by one skilled in the art, a* and b* are color values
measured with respect to transmissive color [a*(TR) and b*(TR)],
and glass side reflective color [a*(BRA and b*(BRA)].
TABLE-US-00003 TABLE 3 Comparative Example (CE) vs. Example 1
(Optical Parameters) [Ill. C 2 deg.] Comparative Example 1 on
Example (CE) glass substrate on glass (FIG. 4a Glass substrate
Parameter substrate embodiment) alone TR(%) 88% 85.47% 91.7% a*
(TR) -1 -0.60 -0.35 b* (TR) 1.5 1.05 0.18 BRA(%) 5.8% 8.20% 8.11%
a* (BRA) -2.2 -2.37 -0.17 b* (BRA) -6 -6.43 -0.74
[0078] The glass side visible reflection (BRA) of the coating 41 on
the glass substrate 40 for Example 1 more closely matches the
visible reflection of the glass substrate 40 alone (8.20% vs.
8.11%), compared to the CE (5.8% vs. 8.11%). Thus, the patterned
coating 41 on the glass substrate 40 is much less visible for
Example 1 compared to the CE.
[0079] In certain example embodiments of this invention (e.g.,
FIGS. 2-7), the coating 41 (unlike the CE) on a glass substrate 40
has a film side visible reflectance (RA) from 550-600 nm of from
7-10%, more preferably from 7.5 to 8.5%. And in certain example
embodiments of this invention, the coating 41 (unlike the CE) on a
glass substrate 40 has a glass side visible reflectance (BRA) from
550-600 nm of from 7-13%, more preferably from 7-9%, and still more
preferably from 7.25 to 8.75% (the BRA for the CE was only 5.8% as
seen above). In certain example embodiments of this invention,
unlike the CE, there is no more than a 2.0 difference (more
preferably no more than a 1.5 or 1.0 difference) at 550 nm and/or
600 nm, or in the range from 550-600 nm, between: (a) the film side
and/or glass side visible reflectance percentage of a coated
article including the coating 41 on a glass substrate 40 (in the
area where the coating 41 is present), and (b) the visible
reflectance percentage of the glass substrate alone in areas where
coating 41 is not present. This can be seen in FIG. 6 for example
(see also FIGS. 8(a)-(b)). In contrast, for example, for the CE it
can be seen from the above that there is a 2.31 difference
(8.11%-5.8%=2.31) between (a) the glass side visible reflectance
percentage of a coated article including the CE coating on a glass
substrate 40 in the area where the coating 41 is present, and (b)
the visible reflectance percentage of the glass substrate alone,
which is too much of a difference and renders the electrodes and
traces easily visible to viewers viewing the device from the side
of the finger shown in FIG. 7. Example embodiments of this
invention have reduced this difference to no more than 2.0, more
preferably no more than 1.5, and most preferably no more than
1.0.
[0080] While the Comparative Example (CE) is discussed above in
connection with comparison to Example 1, it is noted that the
coatings of both the CE and Example 1 may be used as the electrodes
and/or traces in a touch panel according to example embodiments of
this invention.
[0081] In certain example embodiments, an antireflective (AR)
coating may be provided between the glass substrate 40 and the
coating 41 of any of FIGS. 4(a)-(h) to still more closely match the
visible reflectance (glass side and/or film side) of the coating to
that of the supporting substrate (glass plus AR coating). The AR
coating may be applied across the entire or substantially the
entire major surface of the glass substrate 40, and unlike the
transparent conductive coating 41, the AR coating need not be
patterned in certain example embodiments. As another optional, an
AR coating may in effect be provided as a bottom portion of the
coating 41 in order to add AR effect to the coating 41.
[0082] FIG. 4(b) illustrates a multilayer transparent conductive
coating 41 according to another example embodiment which may be
provided, either directly or indirectly, substrate 40 in any of the
devices or products discussed herein (e.g., see FIGS. 2-3, 7 and
9-17). Substrate 40 may be, for example, glass or glass coated with
an AR coating. Coating 41 of the FIG. 4(b) embodiment may include,
for example, base dielectric layer 61 or of including silicon
nitride (e.g., Si.sub.3N.sub.4 or other suitable stoichiometry),
which may or may not be doped with Al and/or oxygen; low index
dielectric layer 62 of or including silicon oxide (e.g., SiO.sub.2
or other suitable stoichiometry) which may or may not be doped with
Al and/or nitrogen; a dielectric high index layer 43 of or
including a material such as titanium oxide or niobium oxide, which
may include titanium oxide (e.g., TiO.sub.2 or other suitable
stoichiometry); a dielectric layer 44 of or including zinc oxide
(optionally doped with Al) or any of the other materials discussed
herein in connection with layer 44, to be in contact with the
silver-based layer; a silver-based conductive layer 46 on and
directly contacting the zinc oxide based layer 44; an upper contact
layer 47 including nickel and/or chromium which may be oxided
and/or nitrided, that is over and contacting the silver-based
conductive layer 46; a dielectric high index layer 48 of or
including a material such as titanium oxide or niobium oxide, which
may include titanium oxide (e.g., TiO.sub.2 or other suitable
stoichiometry); a dielectric layer 49 of or including tin oxide
(e.g., SnO.sub.2); and an outer-most protective dielectric layer 50
of or including silicon nitride and/or silicon oxynitride. Each of
the layers in the coating 41 is designed to be substantially
transparent (e.g., at least 70% or at least 80% transparent) to
visible light. The silver layer 46 may or may not be doped with
other materials as discussed herein.
[0083] The coatings 41 of FIGS. 4(a)-(c) are designed to achieve
good conductivity while at the same time to reduce visibility by
more closely matching is visible reflectance (glass side and/or
film side visible reflectance) to the visible reflectance of the
supporting substrate 40. Substantial matching of the visible
reflectance of the coating 41 and the visible reflectance of the
supporting glass substrate 40 reduces visibility of the electrodes
and traces formed of the coating material 41. While various
thicknesses and materials may be used in layers in different
embodiments of this invention, example thicknesses and materials
for the respective sputter-deposited layers of coating 41 on the
glass substrate 40 in the FIG. 4(b) embodiment are as follows, from
the glass substrate outwardly:
TABLE-US-00004 TABLE 4 FIG. 4(b) Transparent Conductive Coating
Preferred More Preferred Example Ref Material Thickness (.ANG.)
Thickness (.ANG.) Thickness (.ANG.) 61 Si.sub.xN.sub.y 200-500
250-400 318 62 SiO.sub.x 200-600 400-500 440 43 TiO.sub.x 130-185
150-185 354 44 ZnO 50-140 60-100 83 46 Ag 90-160 115-140 124 47
NiCrOx 15-50 15-30 20 48 TiO.sub.x 10-60 15-35 23 49 SnO.sub.2
80-220 110-150 130 50 Si.sub.xN.sub.y 300-400 300-320 303
[0084] It is noted that the above materials for FIG. 4(b) coating
41 are exemplary, so that other material(s) may instead be used and
certain layers may be omitted in certain example embodiments. This
coating has both low sheet resistance, and has layers designed to
reduce visibility of the coating 41 on the supporting glass
substrate 40. In certain exemplary embodiments, glass substrate 40
with coating 41 thereon may be heat treated (e.g., thermally
tempered), e.g., after coating, or chemically strengthened before
coating. As with the FIG. 4(a) embodiment, the silver-based coating
41 of the FIG. 4(b) embodiment is inexpensive, has a low sheet
resistance (preferably less than 15 ohms/square, more preferably
less than about 10 or 5 ohms/square, with an example being
approximately 4 ohms per square) and maintains high visible
transmittance (preferably at least 60%, more preferably at least
70%, more preferably at least 80%, and most preferably at least
84%). The coating 41 is preferably deposited on substantially the
entirety of the major surface of the glass substrate 40, and then
patterned to form the electrodes and/or traces discussed
herein.
Example 2 Vs. Comparative Example (CE)
[0085] Example 2 utilizes a coating according to the FIG. 4(b)
embodiment. Surprisingly and unexpectedly, it has been found that
the FIG. 4(b) coating can surprisingly reduce the visibility of the
coating 41 on the supporting substrate 40, and thus make the
electrodes and traces of the touch panel less visible to users and
therefore the overall panel more aesthetically pleasing compared to
the CE discussed above. This is evidenced, for example, by the
comparison below between a Comparative Example (CE) and Example 2
of this invention, where the coatings include from the glass
substrate outwardly:
TABLE-US-00005 TABLE 5 Comparative Example (CE) vs. Example 2
Example 2 Ref Material Thickness (.ANG.) 61 Si.sub.3N.sub.4 318 62
SiO.sub.2 440 43 TiO.sub.2 354 44 ZnO 83 46 Ag 124 47 NiCrOx 20 48
TiO.sub.2 23 49 SnO.sub.2 130 50 Si.sub.3N.sub.4 303
[0086] FIG. 5 is discussed above, and illustrates properties of the
CE.
[0087] In contrast, FIG. 8(a) is a percent visible
transmission/reflectance vs. wavelength (nm) graph illustrating the
visible transmission (CGN-TR or TR) and glass side visible
reflection (CGN-BRA or BRA) of Example 2 of this invention,
demonstrating that it is transparent to visible light and has a
glass side visible reflectance more closely matched to the
reflectance of the glass substrate alone compared to the CE of FIG.
5. FIG. 8(a) also illustrates the visible transmission (Glass-TR)
and visible reflectance (Glass-BRA) for just the glass substrate
absent the coating. The line plot with the "x" through it in FIG.
8(a) is the glass side visible reflection of the Example 2 coating
41 on the glass substrate 40, and the line plot in FIG. 8(a) with
the triangular marking through it is the visible reflection of the
glass substrate 40 alone without the coating 41 on it. The
difference between these two lines is significant, because it shows
the difference in visible reflection (from the point of view of the
finger in FIG. 7) between (a) areas of the glass substrate and
touch panel where coating 41 is not present (i.e., in non-electrode
and non-trace areas), and (b) areas of the glass substrate and
touch panel where the coating 41 is present (i.e., in electrode and
trace areas). Thus, the larger the difference between these two
lines (the bottom two lines in the FIG. 8(a) graph), the more
visible the electrodes and traces are to a viewer. And the smaller
the difference between these two lines (the bottom two lines in the
FIG. 8(a) graph), the less visible the electrodes and traces are to
a viewer. Comparing FIGS. 5 and 8(a) to each other, it can be seen
that in FIG. 8(a) that there is a much smaller gap (if any) between
these two lines for the visible wavelengths from about 550 nm to
about 650 nm compared to the larger gap for the CE in FIG. 5,
meaning that the electrodes and traces on a touch panel made of the
Example 2 material will be much less visible (compared to the CE
material of FIG. 5) which renders the touch panel more
aesthetically pleasing. In other words, compared to the CE, Example
2 more closely matches the glass side visible reflectance of the
coating 41 on the glass substrate 40 to the visible reflection of
the glass substrate 40 in areas where the coating is not present,
and thus make the electrodes and traces of the touch panel less
visible to users and therefore more aesthetically pleasing.
[0088] The table below shows optical differences between the
Comparative Example (CE) and Example 2, where at 550 nm TR is
visible transmission, RA is film side visible reflectance which is
measured viewing the glass/coating combination from the coating
side, and BRA is glass side visible reflectance which is measured
viewing the glass/coating combination from the glass side. As will
be recognized by one skilled in the art, a* and b* are color values
measured with respect to transmissive color [a*(TR) and b*(TR)],
and glass side reflective color [a*(BRA and b*(BRA)].
TABLE-US-00006 TABLE 6 Comparative Example (CE) vs. Example 2
(Optical Parameters) [Ill. C 2 deg.] Comparative Example 2 on
Example (CE) glass substrate on glass (FIG. 4b Glass substrate
Parameter substrate embodiment) alone TR(%) 88% 85.75% 91.7% a*
(TR) -1 -1.05 -0.35 b* (TR) 1.5 -0.31 0.18 BRA(%) 5.8% 7.86% 8.11%
a* (BRA) -2.2 0.02 -0.17 b* (BRA) -6 -0.33 -0.74
[0089] It is relevant here that the glass side visible reflection
(BRA) of the coating 41 on the glass substrate 40 for Example 2
more closely matches the visible reflection of the glass substrate
40 alone (7.86% vs. 8.11%), compared to the CE (5.8% vs. 8.11%).
Thus, the patterned coating 41 on the glass substrate 40 is much
less visible for Example 2 compared to the CE. As discussed above,
in certain example embodiments of this invention (e.g., FIGS. 2-7),
the coating 41 (unlike the CE) on a glass substrate 40 has a film
side visible reflectance (RA) from 550-600 nm of from 7-10%, more
preferably from 7.5 to 8.5%. And in certain example embodiments of
this invention, the coating 41 (unlike the CE) on a glass substrate
40 has a glass side visible reflectance (BRA) from 550-600 nm of
from 7-13%, more preferably from 7-9%, and still more preferably
from 7.25 to 8.75% (the BRA for the CE was only 5.8% as seen
above). As also mentioned above, in certain example embodiments of
this invention there is no more than a 2.0 difference (more
preferably no more than a 1.5 or 1.0 difference) at 550 nm and/or
600 nm, or in the range from 550-600 nm, between: (a) the film side
and/or glass side visible reflectance percentage of a coated
article including the coating 41 on a glass substrate 40 (in the
area where the coating 41 is present), and (b) the visible
reflectance percentage of the glass substrate alone in areas where
coating 41 is not present. This can be seen in FIG. 8(a) for
example (see also FIGS. 6 and 8(b)). In contrast, for example, for
the CE it can be seen from the above that there is a 2.31
difference (8.11%-5.8%=2.31) between (a) the glass side visible
reflectance percentage of a coated article including the CE coating
on a glass substrate 40 in the area where the coating 41 is
present, and (b) the visible reflectance percentage of the glass
substrate alone, which is too much of a difference and renders the
electrodes and traces easily visible to viewers viewing the device
from the side of the finger shown in FIG. 7. Example embodiments of
this invention have reduced this difference to no more than 2.0,
more preferably no more than 1.5, and most preferably no more than
1.0.
[0090] FIG. 4(c) illustrates a multilayer transparent conductive
coating (41' or 41'', both of which may also be referred to as 41)
according to another example embodiment which may be provided,
either directly or indirectly, substrate 40 in any of the devices
or products discussed herein (e.g., see FIGS. 2-3, 7 and 9-17).
Substrate 40 may be, for example, glass. Coating 41' of the FIG.
4(c) embodiment may include, for example, an antireflective (AR)
section 70 including a dielectric high index layer 71 of or
including a material such as titanium oxide or niobium oxide, which
may include titanium oxide (e.g., TiO.sub.2 or other suitable
stoichiometry); low index dielectric layer 72 of or including
silicon oxide (e.g., SiO.sub.2 or other suitable stoichiometry)
which may or may not be doped with Al and/or nitrogen; a dielectric
high index layer 73 of or including a material such as titanium
oxide or niobium oxide; another low index dielectric layer 74 of or
including silicon oxide (e.g., SiO.sub.2 or other suitable
stoichiometry) which may or may not be doped with Al and/or
nitrogen, and a dielectric layer 75 of or including zirconium oxide
(e.g., ZrO.sub.2 or other suitable stoichiometry). The "substrate"
in the FIG. 4(c) embodiment may be considered the glass 40 plus the
AR section 70 of the coating, as the AR section 70 of the coating
41' need not be patterned along with the rest of the coating 41',
and in such a case the transparent conductive coating of the FIG.
4(c) embodiment may be considered to be made up of just the layers
61, 44, 46, 47 and 50. In other words, in the FIG. 4(c) embodiment,
the multi-layer transparent conductive coating may be considered as
41'' which is made up of layers 61, 44, 46, 47 and 50, and the
"substrate" may be considered to be the combination of the glass 40
and the AR coating 70.
[0091] The coating 41 of the FIG. 4(c) embodiment may further
include, as section 41'', dielectric layer 61 or of including
silicon nitride (e.g., Si.sub.3N.sub.4 or other suitable
stoichiometry), which may or may not be doped with Al and/or
oxygen; a dielectric layer 44 of or including zinc oxide
(optionally doped with Al) or any of the other materials discussed
herein in connection with layer 44, to be in contact with the
silver-based layer; a silver-based conductive layer 46 on and
directly contacting the zinc oxide based layer 44; an upper contact
layer 47 including nickel and/or chromium which may be oxided
and/or nitrided, that is over and contacting the silver-based
conductive layer 46; optionally a dielectric high index layer 48 of
or including a material such as titanium oxide or niobium oxide,
which may include titanium oxide (e.g., TiO.sub.2 or other suitable
stoichiometry); and an outer-most protective dielectric layer 50 of
or including silicon nitride and/or silicon oxynitride. Each of the
layers in the coating 41 of the FIG. 4(a)-(c) embodiments is
designed to be substantially transparent (e.g., at least 70% or at
least 80% transparent) to visible light. Silver layer 46 may or may
not be doped as discussed herein.
[0092] The coating 41 of FIG. 4(c) is designed to achieve good
conductivity while at the same time to reduce visibility by more
closely matching is visible reflectance (glass side and/or film
side visible reflectance) to the visible reflectance of the
supporting substrate. Substantial matching of the visible
reflectance of the coating 41 and the visible reflectance of the
supporting substrate reduces visibility of the electrodes and
traces formed of the coating material 41. While various thicknesses
and materials may be used in layers in different embodiments of
this invention, example thicknesses and materials for the
respective sputter-deposited layers of coating 41 on the glass 40
in the FIG. 4(c) embodiment are as follows, from the glass
outwardly:
TABLE-US-00007 TABLE 7 FIG. 4(c) Coating Preferred More Preferred
Example Ref Material Thickness (.ANG.) Thickness (.ANG.) Thickness
(.ANG.) 71 TiO.sub.x 40-350 50-250 100 72 SiO.sub.x 200-600 300-450
373 73 NbO.sub.x 200-2000 500-1500 1112 74 SiO.sub.x 200-1200
500-950 744 75 ZrO.sub.x 30-120 30-80 50 61 Si.sub.xN.sub.y 150-500
200-400 271 44 ZnO 50-140 60-100 83 46 Ag 90-160 115-150 131 47
NiCrOx 15-50 15-30 20 50 Si.sub.xN.sub.y 300-450 300-350 339
[0093] It is noted that the above materials for FIG. 4(c) coating
41 are exemplary, so that other material(s) may instead be used and
certain layers may be omitted in certain example embodiments. The
coating has both low sheet resistance, and has layers designed to
reduce visibility of the coating 41 on the supporting substrate. In
certain exemplary embodiments, glass substrate 40 with coating 41
thereon may be heat treated (e.g., thermally tempered), e.g., after
coating, or chemically strengthened before coating. As with the
FIG. 4(a)-(b) embodiments, the silver-based coating 41 of the FIG.
4(c) embodiment is inexpensive, has a low sheet resistance
(preferably less than 15 ohms/square, more preferably less than
about 10 or 5 ohms/square, with an example being approximately 4
ohms per square) and maintains high visible transmittance
(preferably at least 60%, more preferably at least 70%, more
preferably at least 80%, and most preferably at least 84%). The
coating 41 is preferably deposited on substantially the entirety of
the major surface of the glass substrate 40 and then patterned to
form the electrodes and traces discussed herein.
Example 3 Vs. Comparative Example (CE)
[0094] Example 3 utilizes a coating according to the FIG. 4(c)
embodiment. Surprisingly and unexpectedly, it has been found that
the FIG. 4(c) coating can surprisingly reduce the visibility of the
coating 41 on the supporting substrate, and thus make the
electrodes and traces of the touch panel less visible to users and
therefore the overall panel more aesthetically pleasing compared to
the CE discussed above. This is evidenced, for example, by the
comparison below between a Comparative Example (CE) and Example 3
of this invention, where the coatings include from the glass
outwardly:
TABLE-US-00008 TABLE 8 Comparative Example (CE) vs. Example 3
Example 3 Ref Material Thickness (.ANG.) 71 TiO.sub.2 100 72
SiO.sub.2 373 73 NbO.sub.x 1112 74 SiO.sub.2 744 75 ZrO.sub.2 50 61
Si.sub.3N.sub.4 271 44 ZnO 83 46 Ag 131 47 NiCrOx 20 50
Si.sub.3N.sub.4 339
[0095] FIG. 5 is discussed above, and illustrates properties of the
CE.
[0096] In contrast, FIG. 8(b) is a percent visible
transmission/reflectance vs. wavelength (nm) graph illustrating the
visible transmission (CGN-TR or TR) and glass side visible
reflection (CGN-BRA or BRA) of Example 3 according to another
example embodiment of this invention, demonstrating that it is
transparent to visible light and has a glass side visible
reflectance more closely matched to the reflectance of the
substrate compared to the CE. FIG. 8(b) also illustrates the
visible transmission (Glass-TR) and visible reflectance (Glass-BRA)
for just the glass substrate and AR section 71-75 absent the other
layers (61, 44, 46, 47 and 50) of the coating. The line plot with
the "x" through it in FIG. 8(b) is the glass side visible
reflection of the Example 3 coating 41 on the glass substrate 40,
and the line plot in FIG. 8(b) with the triangular marking through
it is the visible reflection of the glass substrate 40 with only
the AR section 70-75 thereon. The difference between these two
lines is relevant, because it shows the difference in visible
reflection (from the point of view of the finger in FIG. 7) between
(a) areas of the glass substrate and touch panel where just the AR
section of the coating is present (i.e., in non-electrode and
non-trace areas), and (b) areas of the glass substrate and touch
panel where the entire coating 41 is present (i.e., in electrode
and trace areas). Thus, the larger the difference between these two
lines (the bottom two lines in the FIG. 8(b) graph), the more
visible the electrodes and traces are to a viewer. And the smaller
the difference between these two lines (the bottom two lines in the
FIG. 8(b) graph), the less visible the electrodes and traces are to
a viewer. Comparing FIGS. 5 and 8(b) to each other, it can be seen
that in FIG. 8(b) that there is a much smaller gap (if any) between
these two lines for the visible wavelengths from about 550 nm to
about 650 nm compared to the larger gap for the CE in FIG. 5,
meaning that the electrodes and traces on a touch panel made of the
Example 3 material will be much less visible (compared to the CE
material of FIG. 5) which renders the touch panel more
aesthetically pleasing. In other words, compared to the CE, Example
3 more closely matches the glass side visible reflectance of the
coating 41 on the glass substrate 40 to the visible reflection of
the supporting substrate (glass plus AR layers), and thus make the
electrodes and traces of the touch panel less visible to users and
therefore more aesthetically pleasing.
[0097] The table below shows optical characteristics of Example 3,
where at 550 nm TR is visible transmission, RA is film side visible
reflectance which is measured viewing the glass/coating combination
from the coating side, and BRA is glass side visible reflectance
which is measured viewing the glass/coating combination from the
glass side. As will be recognized by one skilled in the art, a* and
b* are color values measured with respect to transmissive color
[a*(TR) and b*(TR)], and glass side reflective color [a*(BRA and
b*(BRA)]. In the table below for Example 3, the glass substrate
parameters are for the glass substrate with only AR layers 71-75
thereon across the entire substrate 40, and the Example 3
parameters are for the entire coating 41 on the glass substrate 40
(i.e., the AR layers 71-75 may be provided across substantially the
entire substrate whereas the layers 61, 44, 46, 47 and 50 may be
patterned to form the electrodes and traces).
TABLE-US-00009 TABLE 9 Example 3 (Optical Parameters) [Ill. C 2
deg.] Example 3 on Glass substrate glass substrate with only AR
(FIG. 4c layers 71-75 Parameter embodiment) thereon TR(%) 85.61%
94.80% a* (TR) -0.78 -0.30 b* (TR) -0.94 0.35 BRA(%) 4.99% 4.51% a*
(BRA) -0.15 -0.44 b* (BRA) -1.38 -2.34
[0098] The glass side visible reflection (BRA) of the entire
coating 41 on the glass substrate 40 for Example 3 closely matches
the visible reflection of the glass substrate 40 with only the AR
layers 71-75 thereon (4.99% vs. 4.51%). Thus, the patterned coating
portion (61, 44, 46, 47 and 50) on the substrate is much less
visible for Example 3 compared to the CE. In certain example
embodiments of this invention, the coating 41 (unlike the CE) of
this embodiment on a glass substrate 40 has a glass side visible
reflectance (BRA) from 550-600 nm of from 4-13%, more preferably
from 4.5-9%, and still more preferably from 4.5 to 8.75%. As also
mentioned above, in certain example embodiments of this invention
(FIGS. 2-14) there is no more than a 2.0 difference (more
preferably no more than a 1.5 or 1.0 difference) at 550 nm and/or
600 nm, or in the range from 550-600 nm, between: (a) the film side
and/or glass side visible reflectance percentage of a coated
article including the entire coating 41 on a glass substrate 40 (in
the area where the coating 41 is entirely present), and (b) the
visible reflectance percentage of the glass substrate areas where
only the glass 40 and AR layers 71-75 are present. This can be seen
in FIG. 8(b) for example. In contrast, for example, for the CE it
can be seen from the above that there is a 2.31 difference
(8.11%-5.8%=2.31) between (a) the glass side visible reflectance
percentage of a coated article including the CE coating on a glass
substrate 40 in the area where the coating 41 is present, and (b)
the visible reflectance percentage of the glass substrate alone,
which is too much of a difference and renders the electrodes and
traces easily visible to viewers viewing the device from the side
of the finger shown in FIG. 7. Example embodiments of this
invention have reduced this difference to no more than 2.0, more
preferably no more than 1.5, and most preferably no more than
1.0.
[0099] FIG. 4(d) illustrates a multilayer transparent conductive
coating 41 according to another example embodiment which may be
provided, either directly or indirectly, on substrate 40 in any of
the devices or products discussed herein (e.g., see FIGS. 2-3, 7
and 9-17). Substrate 40 may be, for example, glass or glass coated
with an AR coating. Coating 41 of the FIG. 4(d) embodiment may
include, for example, base dielectric layer 61 or of including
silicon nitride (e.g., Si.sub.3N.sub.4 or other suitable
stoichiometry) which may or may not be doped with Al and/or oxygen,
silicon oxynitride, or other suitable dielectric material; lower
contact layer 44 of or including zinc oxide which may be doped with
from about 1-8% Al, or may be of or include any of the other
materials discussed herein in connection with layer 44, and is in
contact with the silver based layer; silver-based conductive layer
46 on and directly contacting the lower contact layer 44; an upper
contact layer 47 including nickel and/or chromium which may be
oxided and/or nitrided that is over and contacting the silver-based
conductive layer 46; dielectric layer 50 of or including silicon
nitride and/or silicon oxynitride or other suitable material,
dielectric layer of or including zirconium oxide (e.g., ZrO.sub.2)
75, and optionally protective layer of or including diamond-like
carbon (DLC) 120. The DLC of layer 120 may, for example, be any of
the DLC materials discussed in any of U.S. Pat. Nos. 6,261,693,
6,303,225, 6,447,891, 7,622,161, and/or 8,277,946, which are
incorporated herein by reference. Each of the layers in the coating
41 is designed to be substantially transparent (e.g., at least 70%
or at least 80% transparent) to visible light. The silver layer 46
may or may not be doped with other materials as discussed herein.
Upper contact layer 47 may be of or include materials such as NiCr,
NiCrO.sub.x, NiCrN.sub.x, NiCrON.sub.x, NiCrMo, MiCrMoO.sub.x,
TiO.sub.x, or the like.
[0100] While various thicknesses and materials may be used in
layers in different embodiments of this invention, example
thicknesses and materials for the respective sputter-deposited
layers of coating 41 on the glass 40 in the FIG. 4(d) embodiment
are as follows, from the glass outwardly:
TABLE-US-00010 FIG. 4(d) Coating Preferred More Preferred Example
Ref Material Thickness (.ANG.) Thickness (.ANG.) Thickness (.ANG.)
61 Si.sub.xN.sub.y 150-500 200-400 271 44 ZnO 50-140 60-100 83 46
Ag 90-160 115-150 131 47 NiCrNx 15-50 15-30 20 50 Si.sub.xN.sub.y
200-500 300-350 339 75 ZrO.sub.2 40-300 50-200 100 120 DLC 10-200
20-150 40-120
[0101] FIG. 4(e) illustrates a multilayer transparent conductive
coating 41 according to another example embodiment which may be
provided, either directly or indirectly, on substrate 40 in any of
the devices or products discussed herein (e.g., see FIGS. 2-3, 7
and 9-17). The FIG. 4(e) coating is the same as the FIG. 4(d)
coating, except that layer 120 is not present in the FIG. 4(e)
coating.
[0102] FIG. 4(f) illustrates a multilayer transparent conductive
coating 41 according to another example embodiment which may be
provided, either directly or indirectly, on substrate 40 in any of
the devices or products discussed herein (e.g., see FIGS. 2-3, 7
and 9-17). Substrate 40 may be, for example, glass or glass coated
with an AR coating. Coating 41 of the FIG. 4(f) embodiment may
include, for example, base dielectric layer 61 or of including
silicon nitride (e.g., Si.sub.3N.sub.4 or other suitable
stoichiometry), which may or may not be doped with Al and/or
oxygen; lower contact layer 101 in contact with the silver based
layer and which may include nickel and/or chromium which may be
oxided and/or nitrided; silver-based conductive layer 46 on and
directly contacting the lower contact layer 101; an upper contact
layer 47 including nickel and/or chromium which may be oxided
and/or nitrided that is over and contacting the silver-based
conductive layer 46; and an protective dielectric layer 50 of or
including silicon nitride and/or silicon oxynitride. Each of the
layers in the coating 41 is designed to be substantially
transparent (e.g., at least 70% or at least 80% transparent) to
visible light. The silver layer 46 may or may not be doped as
discussed herein. Upper and lower contact layers 47 and 101 may be
of or include materials such as NiCr, NiCrO.sub.x, NiCrN.sub.x,
NiCrON.sub.x, NiCrMo, MiCrMoO.sub.x, TiO.sub.x, or the like.
Optionally, a layer of or including diamond-like carbon (DLC) or
zirconium oxide (e.g., ZrO.sub.2) may be provided as a protective
overcoat in the coating 41 over the layer 50 in the FIG. 4(f)
embodiment. The zirconium oxide and/or DLC layers discussed herein
provide for scratch resistance, and resistance to stains and
cleaning chemicals in applications such as shower door/wall touch
panel applications. The use of one or more of NiCr, NiCrO.sub.x,
NiCrN.sub.x, NiCrON.sub.x, NiCrMo, and/or MiCrMoO for layer lower
contact layer 101, instead of crystalline zinc oxide layer 44,
allows the conductivity of the silver layer 46 to be reduced in a
manner that is sometimes desirable, as discussed herein.
[0103] While various thicknesses and materials may be used in
layers in different embodiments of this invention, example
thicknesses and materials for the respective sputter-deposited
layers of coating 41 on the glass 40 in the FIG. 4(f) embodiment
are as follows, from the glass outwardly:
TABLE-US-00011 FIG. 4(f) Coating Preferred More Preferred Example
Ref Material Thickness (.ANG.) Thickness (.ANG.) Thickness (.ANG.)
61 Si.sub.xN.sub.y 10-500 20-200 100 101 NiCrN.sub.x 5-50 10-30 20
46 Ag 50-160 115-150 131 47 NiCrNx 5-50 10-30 20 50 Si.sub.xN.sub.y
100-500 200-300 250
[0104] FIG. 4(g) illustrates a multilayer transparent conductive
coating 41 according to another example embodiment which may be
provided, either directly or indirectly, on substrate 40 in any of
the devices or products discussed herein (e.g., see FIGS. 2-3, 7
and 9-17). Substrate 40 may be, for example, glass or glass coated
with an AR coating. Coating 41 of the FIG. 4(g) embodiment may
include, for example, base dielectric layer 61 or of including
silicon nitride (e.g., Si.sub.3N.sub.4 or other suitable
stoichiometry), which may or may not be doped with Al and/or
oxygen; lower contact layer 44 as discussed above in connection
with other figures; silver-based conductive layer 46 on and
directly contacting the lower contact layer 44; an upper contact
layer 47 including nickel and/or chromium which may be oxided
and/or nitrided that is over and contacting the silver-based
conductive layer 46; dielectric layer 50 of or including silicon
nitride and/or silicon oxynitride, which may be doped with from
about 1-8% (atomic %) Al; and protective overcoat of or including
zirconium oxide (e.g., ZrO.sub.2) 75. Each of the layers in the
coating 41 is designed to be substantially transparent (e.g., at
least 70% or at least 80% transparent) to visible light. The silver
layer 46 may or may not be doped with other materials as discussed
herein. Upper contact layer 47 may be of or include materials such
as NiCr, NiCrO.sub.x, NiCrN.sub.x, NiCrON.sub.x, NiCrMo,
MiCrMoO.sub.x, TiO.sub.x, or the like. Optionally, a layer of or
including diamond-like carbon (DLC) may be provided as a protective
overcoat in the coating 41 over the layer 75 in the FIG. 4(g)
embodiment. Note that layer 47 may optionally be omitted from the
FIG. 4(g) embodiment in certain example embodiments of this
invention.
[0105] While various thicknesses and materials may be used in
layers in different embodiments of this invention, example
thicknesses and materials for the respective sputter-deposited
layers of coating 41 on the glass 40 in the FIG. 4(g) embodiment
are as follows, from the glass outwardly:
TABLE-US-00012 FIG. 4(g) Coating Preferred More Preferred Example
Ref Material Thickness (.ANG.) Thickness (.ANG.) Thickness (.ANG.)
61 Si.sub.xN.sub.y 10-500 20-200 100 44 ZnO 20-140 30-100 83 46 Ag
50-160 115-150 131 47 NiCrNx 5-50 10-30 20 50 Si.sub.xN.sub.y
100-500 200-300 250 75 ZrO.sub.2 40-300 50-200 100
[0106] FIG. 4(h) illustrates another double silver multilayer
transparent conductive coating 41 according to another example
embodiment which may be provided, either directly or indirectly, on
substrate 40 in any of the devices or products discussed herein
(e.g., see FIGS. 2-3, 7 and 9-17). Substrate 40 may be, for
example, glass or glass coated with an AR coating. Coating 41 of
the FIG. 4(h) embodiment may include, for example, base dielectric
layer 61 or of including silicon nitride (e.g., Si.sub.3N.sub.4 or
other suitable stoichiometry), which may or may not be doped with
Al and/or oxygen; lower contact layers 44 as discussed above in
connection with other figures; silver-based conductive layers 46 on
and directly contacting the lower contact layers 44; upper contact
layers 47 including nickel and/or chromium which may be oxided
and/or nitrided that are over and contacting the respective
silver-based conductive layers 46; dielectric layers 50 of or
including silicon nitride and/or silicon oxynitride, which may be
doped with from about 1-8% (atomic %) Al; and dielectric layers 49
of or including tin oxide or zinc stannate for example. Each of the
layers in the coating 41 is designed to be substantially
transparent (e.g., at least 70% or at least 80% transparent) to
visible light. The silver layer 46 may or may not be doped with
other materials as discussed herein. Upper contact layers 47 may be
of or include materials such as NiCr, NiCrO.sub.x, NiCrN.sub.x,
NiCrON.sub.x, NiCrMo, MiCrMoO.sub.x, TiO.sub.x, or the like.
Optionally, a layer of or including diamond-like carbon (DLC) may
be provided as a protective overcoat in the coating 41 over the top
layer 50 in the FIG. 4(h) embodiment, or alternatively the top
layer 50 could be replaced with an overcoat of or including
zirconium oxide. Note that certain layer(s) may optionally be
omitted from the FIG. 4(h) embodiment, and/or other layer(s) may
optionally be added, in certain example embodiments of this
invention.
[0107] While various thicknesses and materials may be used in
layers in different embodiments of this invention, example
thicknesses and materials for the respective sputter-deposited
layers of coating 41 on the glass 40 in the FIG. 4(h) embodiment
are as follows, from the glass outwardly:
TABLE-US-00013 FIG. 4(h) Coating Preferred More Preferred Example
Ref Material Thickness (.ANG.) Thickness (.ANG.) Thickness (.ANG.)
61 Si.sub.xN.sub.y 10-500 20-200 100 44 ZnO 20-140 30-100 83 46 Ag
50-160 100-150 131 47 NiCrO.sub.x 5-50 10-30 20 49 SnO.sub.2
50-1000 100-500 100-300 50 Si.sub.xN.sub.y 100-500 200-300 250 49
SnO.sub.2 50-1000 100-500 100-300 44 ZnO 20-140 30-100 83 46 Ag
50-160 100-150 131 47 NiCrO.sub.x 5-50 10-30 20 49 SnO.sub.2 50-400
50-250 100-200 50 Si.sub.xN.sub.y 10-500 50-250 80-200
[0108] In the FIG. 4(h) coating, as with other double silver
coatings discussed herein, the lower silver layer 46 may be used as
the conductor for one set of electrodes of the touch panel, and the
upper silver layer 46 may be used as the conductor for another set
of electrodes. For example, in any embodiment herein, the lower
silver layer 46 may be used as the conductor for the transmit
electrodes (T) of the touch panel, and the upper silver layer 46
may be used as the conductor for the receive electrodes (R) of the
touch panel, or vice versa. In such a scenario, the transmit
electrodes and receive electrodes may be on different respective
planes.
[0109] The coatings shown in any of FIGS. 4-6 of parent case Ser.
No. 13/685,871 (now U.S. Pat. No. 9,354,755, and incorporated
herein by reference), and/or described elsewhere in parent case
Ser. No. 13/685,871, may also be used as the multi-layer
transparent conductive coatings 41 in touch panels for electrodes
and/or traces in any of the various embodiments discussed
herein.
[0110] The patterned low sheet resistance coatings 41 herein (e.g.,
any of the FIG. 2-8 embodiments) may also be used in low resolution
touch panel applications (e.g., see FIG. 9). Example applications
for touch panels discussed herein are interactive storefronts,
preferably standalone, but possibly also in combination with a
projected image on the glass assembly or with direct view displays,
shower controls on glass based shower doors or glass based shower
walls, light controls on glass walls in office buildings, controls
for appliances such as ovens, stovetops, refrigerators, and the
like. The glass substrate 40 may be flat or curved (e.g., heat
bent) in different embodiments of this invention. The silver based
coatings 41 discussed herein are advantageous with respect to bent
substrates, because conventional ITO coatings for touch panels are
typically highly crystalline and relatively thick and brittle when
bent, which can readily lead to failure of the ITO. In bent glass
applications, the glass or plastic substrate 40 may be bent for
example via heat bending, cold lamination, or any other suitable
technique, and may end up with a curvature radius after bending of
from about 0.05 to 100 nm. Low resolution touch panels on glass
allow the user to select information or otherwise interact with the
glass surface while simultaneously viewing what's behind the glass.
In a standalone configuration, for example, the touch panel may be
operated from both sides of the glass panel. Low resolution
capacitive touch panels may be for example an array of 5.times.5
touch buttons, each about a square inch and separated by about half
an inch, as shown in FIG. 9. The touch principle of operation may
be self-capacitance which can detect gloved fingers as well as bare
fingers. The interconnect flex circuit in FIG. 9 is connected to a
touch controller and the function of each button can therefore be
reconfigured in software or firmware. The lower resolution touch
interface is easier to make than a multi-touch panel on top of a
high resolution LCD, because the minimum feature size for the
patterning coating 41 by laser, photolithography or other method
can be much larger. For example, the minimum feature size for the
traces could be about 1 mm, so that the requirements for pinholes,
scratches and other defects in the glass and in the coating are
greatly relaxed. In other words, it allows the use of standard soda
lime glass 40 and coatings 41 produced in a horizontal
architectural coater. For certain low resolution touch
applications, there is no need for the advanced clean room
facilities that typically are used to produce high resolution
multi-touch panels for phones, tablets, laptops and larger size
multi-touch panels. The wider traces (e.g .about.1 mm) also reduce
the resistance and signal delay from the touch electrodes.
[0111] Referring to the laminated FIG. 10 embodiment (the coatings
of any of FIGS. 2-8 may be used in the FIG. 10 embodiment, as well
as in the FIG. 7 lamination embodiment), to further protect the
patterned silver based coating 41 from corrosion in a standalone
application, the touch panel substrate 40 (with or without an AR
coating thereon between 40 and 41) is laminated to another glass
substrate 45 with PVB, EVA, or other polymer inclusive lamination
material 52. The PVB 52 based laminating layer for example will
encapsulate the patterned coating 41, so that corrosion is further
inhibited. Of course, as explained herein, the touch panel need not
include the second substrates or the laminating layer in certain
instances and may be made up of the glass substrate 40 and the
electrodes/traces/circuitry discussed herein.
[0112] FIGS. 15-17 are cross sectional views of capacitive touch
panels according to various embodiments of this invention that
include additional functional film 300. FIG. 15 is a cross
sectional view of a capacitive touch panel according to an example
embodiment of this invention, including the transparent conductive
coating pattern 41 according to any of FIGS. 2, 3, 4 (any of
4(a)-(h)), 7, 8, 9, or 10 on surface #2, and an additional
functional film 300 provided on the surface adapted to be touched
by a user. Note the user's finger shown in FIG. 15. Meanwhile, FIG.
16 is a cross sectional view of a capacitive touch panel according
to another example embodiment of this invention, including the
transparent conductive coating pattern 41 according to any of FIG.
2, 3, 4, 7, 8, 9, or 10 on surface #3, and an additional functional
film 300 provided on the surface adapted to be touched by a user.
In the laminated embodiments of FIGS. 15-16, to further protect the
patterned silver based coating 41 from corrosion, the touch panel
substrate 40 (glass or plastic, with or without an AR coating
thereon between 40 and 41) is laminated to another glass substrate
45 (or 200) with PVB or other polymer inclusive lamination material
52. The laminating material (e.g., EVA or PVB) 52 will encapsulate
the patterned coating 41, so that corrosion is further inhibited.
And FIG. 17 is a cross sectional view of a monolithic capacitive
touch panel according to another example embodiment of this
invention, including the transparent conductive coating pattern 41
according to any of FIG. 2, 3, 4, 7, 8, 9, or 10 on surface #2, and
additional functional films 300 and 301. The FIG. 17 monolithic
embodiment may be designed for the user to touch either major
surface of the touch panel. An interconnect 400, such as a flexible
circuit, is provided for allowing the electrodes 41 of the touch
panel to communicate with processing circuitry such as the
processor discussed above.
[0113] Functional film 300 and/or 301 in FIGS. 15-17 may be made up
of one or more layers, and may be one or more of: an index-matching
film, an antiglare film, an anti-fingerprint film, and
anti-microbial film, a scratch resistant film, and/or an
antireflective (AR) film. Unlike the electrode/trace coating 41,
functional films 300 and 301 need not be patterned and may be
applied across substantially the entirety of the substrate 40 (or
45).
[0114] When functional film 300 and/or 301 is an index matching
(see also index matching film 85 in FIG. 7), this is provided to
reduce the refractive index different between the areas/surfaces
adjacent the two sides of the index matching film, in order to
reduce visible reflections and render the touch panel more
aesthetically pleasing. Laminating layers 52 in FIGS. 15-16 may
also be index matching films. Index matching films may or may not
be adhesive types in different embodiments of this invention. Thus,
the index matching film has a refractive index value that is valued
between the respective refractive index values of the
areas/surfaces on both sides of the index matching film. For
example, in FIG. 7 the index matching film 85 has a refractive
index value between the refractive index values of coating 41 and
substrate 200. In a similar manner, in FIG. 15 the index matching
film 300 would have a refractive index value between the refractive
index values of substrate 40 and air. In a similar manner, in FIG.
17 the index matching film 301 would have a refractive index value
between the refractive index values of coating 41 and air. Example
index matching films include optically clear adhesives and index
matching laminating material.
[0115] When functional film 300 in FIGS. 15-17 is an antiglare
film, this is provided to reduce glare off the front of the touch
panel in order to render the touch panel more aesthetically
pleasing. Example anti-glare films that may be used are described
in U.S. Pat. Nos. 8,114,472 and 8,974,066, which are incorporated
herein by reference. Moreover, an antiglare surface at surface #1
of the touch panel may be obtained by a short or weak acid etch of
surface #1 (the surface shown being touched in FIGS. 15-17).
[0116] When functional film 300 in FIGS. 15-17 is an
anti-fingerprint film, this is provided to reduce visibility of
fingerprints on the touch panel to render the touch panel more
aesthetically pleasing. Example anti-fingerprint films that may be
used are described in U.S. Pat. No. 8,968,831, which is
incorporated herein by reference. Anti-fingerprint or anti-smudge
films may be obtained for example with an oleo-phobic coating
and/or roughened surface. Spray-on anti-fingerprint coatings, such
as fluorocarbon compounds, with limited durability, may also be
used. Such film may increase the initial contact angle of surface
#1 (for sessile drop of water) of the touch panel to a value of at
least 90 degrees, more preferably at least 100 degrees, and most
preferably at least 110 degrees.
[0117] When functional film 300 in FIGS. 15-17 is an anti-microbial
film, this is provided to kill germs at the front of the touch
panel in order to render the touch panel more health appealing.
Example anti-microbial films that may be used include silver
colloids, rough titanium oxide, porous titanium oxide, doped
titanium oxide, and may be described in U.S. Pat. Nos. 8,647,652,
8,545,899, 7,846,866, 8,802,589, 2010/0062032, 7,892,662,
8,092,912, and 8,221,833, which are all incorporated herein by
reference.
[0118] When functional film 300 in FIGS. 15-17 is a scratch
resistant film, this is provided to reduce scratching and improve
durability of the touch panel. Example scratch resistant films may
be made of ZrO.sub.2 or DLC. When functional film 300 is of or
includes DLC, the DLC may for example be any of the DLC materials
discussed in any of U.S. Pat. Nos. 6,261,693, 6,303,225, 6,447,891,
7,622,161, and/or 8,277,946, which are incorporated herein by
reference.
[0119] When functional film 300 in FIGS. 15-17 is an antireflective
(AR) film, this is provided to reduce visible reflections off the
front of the touch panel to render the panel more aesthetically
pleasing. Example AR films that may be used are described in U.S.
Pat. Nos. 9,556,066, 9,109,121, 8,693,097, 7,767,253, 6,337,124,
and 5,891,556, the disclosures of which are hereby incorporated
herein by reference. In certain example embodiments, the AR film
may be part of the multi-layer transparent conductive coating
(e.g., see AR film 70 which is part of coating 41' in FIG.
4(c)).
[0120] It is noted that in various embodiments of this invention,
electrode patterns other than a rectangular array of buttons can be
envisioned including patterns allowing swiping, circular patterns
for dials, and so forth. Potential applications include
storefronts, commercial refrigerators, appliances, glass walls in
office or other environments, transportation, dynamic glazing,
vending machines, and so forth, where a see-through low resolution
touch panel is beneficial as a user interface.
[0121] The sputter-deposited coating 41 discussed above in
connection with FIGS. 2-10 may be formed and patterned in any of a
variety of manners. For example, the sputter-deposited coating 41
may be formed by inkjet printing and lift-off (see FIG. 11), metal
shadow mask patterning (see FIG. 12), photolithograph (see FIG.
13), or laser patterning (see FIG. 14(a)).
[0122] As explained above, it is sometimes desirable to pattern the
silver inclusive coating into the electrodes using laser patterning
techniques, as opposed to conventional photolithography (e.g., see
FIG. 14(a)). In certain example embodiments, such as shown in FIGS.
3(f)-(g), it would be desirable to arrange respective sets of
transmitting (T) and receiving (R) electrodes of a silver-based
mutual capacitance touch sensor in an X-Y configuration using a
patterning process on a completed layer stack (e.g., see the
multi-layer coating of FIG. 4(h)), preferably by laser scribing. An
issue is that to define the two sets of X-Y
electrodes--transmitting and receiving--provided in two parallel
planes as an orthogonal matrix faces a challenge of scribing the
electrodes in the X direction without damaging the underlying
electrodes oriented along the Y direction, or vice versa. Thus, in
an example embodiment, various wavelengths are used to pattern the
two sets of electrodes (T and R) independently. In another example
embodiment, the two sets of electrodes are patterned from different
sides of the supporting glass substrate 40 either using the same
wavelength or using at least two different wavelengths.
[0123] In certain example embodiments, different electrodes of the
touch panel may be formed by different silver based layers 46 of
the same or different multi-layer coatings. In patterning the
electrodes (T) and (R), different laser scribing wavelengths may be
used to pattern different respective silver based layers 46, of the
same or different multi-layer coating(s) 41, in certain example
embodiments. For example, when first (e.g., transmit) and second
(e.g., receive) electrodes of the touch panel overlap each other
(e.g., see FIGS. 3(f)-(g)), a first laser scribing wavelength may
be used when patterning the first silver based layer 46 into the
first electrode(s), and a second laser scribing wavelength may be
used when patterning the second silver based layer 46 into the
second electrode(s). For example, transmit electrodes (T) in FIGS.
3(f)-(g) may be laser patterned using a first wavelength(s), and
receive electrodes (R) in FIGS. 3(f)-(g) may be laser patterned
using a different second wavelength(s). Advantageously, the use of
the different wavelengths reduces damage to electrode(s) not
intended to be patterned in a given procedure.
[0124] In certain example embodiments, when different electrodes of
the touch panel may be formed by different silver based layers 46
of the same or different multi-layer coatings 41, a first set of
electrodes (e.g., T) may be patterned by laser scribing from a
first side of the supporting glass substrate 40, whereas a second
set of electrodes (e.g., R) may be patterned by laser scribing from
an opposite second side of the supporting glass substrate 40. Thus,
since the transmit and receive electrodes are on the same side of
the glass substrate 40, one of the two laser patterning procedures
is performed through the supporting glass substrate 40. For
example, referring to FIGS. 3(f)-(g) and 4(h), transmit electrodes
(T) may be laser patterned from a first side of the supporting
glass substrate 40, whereas receive electrodes (R) may be laser
patterned form the opposite second side of the supporting glass
substrate 40 so that the laser beam for patterning the receive
electrodes (R) passes through the glass substrate 40.
Advantageously, this technique reduces damage to electrodes not
intended to be patterned in a given laser patterning procedure. The
embodiment involving laser patterning of different electrodes from
opposite sides of the supporting glass substrate may, or may not,
be used in combination with the embodiment using different
wavelengths to pattern different electrodes.
[0125] Referring to FIGS. 14(a)-14(b), it has been found that the
upper silver based layer 46 (solid line in FIG. 14(b)) in a double
silver coating such as shown in FIG. 4(h) is more optically
absorbent in the wavelength range of 800-900 nm, while the maximum
absorption of the bottom silver layer 46 (dotted line in FIG.
14(b)) is shifted to shorter wavelengths. This differentiation
allows a selective laser scribing of the two conductive silver
based layers 46 either from one side (top of the stack, for
instance) or from both sides--e.g., the stack side for the top
silver and the glass side for the bottom silver layer. In certain
example embodiments, two sets of electrodes may be formed by
scribing using a laser or lasers with at least two different
wavelengths selected to be absorbed preferentially by each of the
silver layers. For example, the bottom silver based layer 46 in the
FIG. 4(h) coating may be laser scribed/patterned using a laser
wavelength of from about 400-620 nm (more preferably from about
500-600 nm) in order to pattern that layer 46 into the transmit
electrodes (T) shown in FIGS. 3(f)-(g), or any other embodiment
herein. The laser patterning of the bottom silver based layer 46 in
the FIG. 4(h) to form the transmit electrodes (T) shown in FIGS.
3(f)-(g) may be done by directing the laser beam through the glass
substrate 40. Meanwhile, the upper silver based layer 46 in the
FIG. 4(h) coating may be laser scribed/patterned using a laser
wavelength of from about 630-1200 nm (more preferably from about
650-1100 nm, and most preferably from about 700-1000 nm) in order
to pattern that layer 46 into the receive electrodes (R) shown in
FIGS. 3(f)-(g), or any other embodiment herein. The laser
patterning of the upper silver based layer 46 in the FIG. 4(h) to
form the overlying receive electrodes (R) shown in FIGS. 3(f)-(g)
may be done by directing the laser beam from above the coating 41
so that the laser beam reaches the silver layer 46 before reaching
the glass substrate 40. The use of the different wavelengths to
pattern the different silver based layers can be advantageous in
reducing damage to the silver layer not intended to be patterned in
a given patterning procedure, as can the use of lasers from
opposite sides of the glass substrate.
[0126] In an example embodiment of this invention, there is
provided a method of making a capacitive touch panel comprising a
glass substrate; a patterned multi-layer transparent conductive
coating supported by the substrate, the multi-layer transparent
conductive coating including a first conductive layer comprising
silver, a dielectric layer located between at least the substrate
and the first conductive layer comprising silver, and a dielectric
layer comprising one or more of: zirconium oxide, silicon nitride,
and tin oxide, located over at least the first conductive layer
comprising silver; a first set of electrodes; a second set of
electrodes; wherein the first and second sets of electrodes are
configured for allowing touch position to be determined, wherein at
least some of the electrodes comprise the multi-layer transparent
conductive coating; the method comprising: laser patterning the
first conductive layer comprising silver with a first wavelength in
forming the first set of electrodes; and forming the second set of
electrodes by laser patterning (i) with a second wavelength
different from the first wavelength, and/or (ii) with a laser beam
from an opposite side of the substrate than a laser beam used in
laser patterning the first conductive layer.
[0127] In the method of the immediately preceding paragraph, the
patterned multi-layer transparent conductive coating may further
comprise a second conductive layer comprising silver, and another
dielectric layer (e.g., silicon nitride or tin oxide) located
between at least the first and second conductive layers comprising
silver, wherein the first set of electrodes and the second set of
electrodes may each comprise the multi-layer transparent conductive
coating, and wherein said forming the second set of electrodes by
laser patterning with the second wavelength different from the
first wavelength may comprise laser patterning the second
conductive layer comprising silver with the second wavelength. The
first conductive layer comprising silver of the patterned
multi-layer transparent conductive coating may be a conductor of
the first set of electrodes, and the second conductive layer
comprising silver of the patterned multi-layer transparent
conductive coating may be a conductor of the second set of
electrodes.
[0128] In the method of any of the preceding two paragraphs, the
electrodes in the first set of electrodes may be oriented
substantially perpendicular (perpendicular plus/minus ten degrees)
to the electrodes in the second set of electrodes, as viewed from
above.
[0129] In the method of any of the preceding three paragraphs, the
electrodes in the first set may be receive electrodes, and the
electrodes in the second set may be transmit electrodes.
[0130] In the method of any of the preceding four paragraphs, the
transmit electrodes may have a higher sheet resistance (R.sub.s)
than the receive electrodes, wherein the transmit electrodes may
have a sheet resistance (R.sub.s) at least 1 ohm/square higher than
a sheet resistance of the receive electrodes. The transmit
electrodes may have a sheet resistance (R.sub.s) at least 5
ohms/square higher than a sheet resistance of the receive
electrodes.
[0131] In the method of any of the preceding five paragraphs, the
method may further comprise doping the conductive layer(s)
comprising silver. The doping may comprise doping the conductive
layer(s) comprising silver with from about 0.05 to 3.0% (wt. %) of
one or more of Zn, Pt, Pd, Ti, and Al.
[0132] In the method of any of the preceding six paragraphs, the
coating may further comprise a layer comprising Ni and/or Cr
located over and contacting the conductive layer comprising
silver.
[0133] In the method of any of the preceding seven paragraphs, the
dielectric layer comprising one or more of zirconium oxide, silicon
nitride, and tin oxide, may comprise silicon nitride which may
optionally be doped with oxygen and/or aluminum.
[0134] In the method of any of the preceding eight paragraphs, the
dielectric layer located between at least the glass substrate and
the conductive layer comprising silver may comprise an oxide of
titanium, or silicon nitride which may optionally be doped with
aluminum and/or oxygen.
[0135] In the method of any of the preceding nine paragraphs, the
glass substrate may further support a functional film, wherein the
functional film may be one or more of an antiglare film, an
anti-microbial film, and an anti-fingerprint film, and may be
located on an opposite side of the glass substrate than the
transparent conductive coating.
[0136] In the method of any of the preceding ten paragraphs, the
touch panel, including the electrodes, may have a visible
transmission of at least 70%.
[0137] In the method of any of the preceding eleven paragraphs, the
first wavelength may be from 400-620 nm (more preferably from
500-600 nm), and the second wavelength may be from 630-1200 nm
(more preferably from 650-1100 nm).
[0138] The forgoing exemplary embodiments are intended to provide
an understanding of the disclosure to one of ordinary skill in the
art. The forgoing description is not intended to limit the
inventive concept described in this application, the scope of which
is defined in the following claims.
* * * * *