U.S. patent application number 14/115091 was filed with the patent office on 2014-07-03 for disk having an electric connecting element.
This patent application is currently assigned to Saint-Gobain Glass France. The applicant listed for this patent is Harald Cholewa, Christoph Degen, Lothar Lesmeister, Mitja Rateiczak, Bernhard Reul, Andreas Schlarb. Invention is credited to Harald Cholewa, Christoph Degen, Lothar Lesmeister, Mitja Rateiczak, Bernhard Reul, Andreas Schlarb.
Application Number | 20140182932 14/115091 |
Document ID | / |
Family ID | 45953163 |
Filed Date | 2014-07-03 |
United States Patent
Application |
20140182932 |
Kind Code |
A1 |
Cholewa; Harald ; et
al. |
July 3, 2014 |
DISK HAVING AN ELECTRIC CONNECTING ELEMENT
Abstract
A disk having at least one electric connecting element is
described. The disk has a substrate, an electrically conductive
structure on a region of the substrate, a connecting element
containing at least chromium-containing steel, and a layer of a
soldering compound that electrically connects the connecting
element to sub-regions of the electrically conductive
structure.
Inventors: |
Cholewa; Harald; (Aachen,
DE) ; Degen; Christoph; (Toenisvorst, DE) ;
Reul; Bernhard; (Herzogenrath, DE) ; Rateiczak;
Mitja; (Wuerselen, DE) ; Schlarb; Andreas;
(Wuppertal, DE) ; Lesmeister; Lothar; (Landgraaf,
NL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Cholewa; Harald
Degen; Christoph
Reul; Bernhard
Rateiczak; Mitja
Schlarb; Andreas
Lesmeister; Lothar |
Aachen
Toenisvorst
Herzogenrath
Wuerselen
Wuppertal
Landgraaf |
|
DE
DE
DE
DE
DE
NL |
|
|
Assignee: |
Saint-Gobain Glass France
Courbevoie
FR
|
Family ID: |
45953163 |
Appl. No.: |
14/115091 |
Filed: |
April 17, 2012 |
PCT Filed: |
April 17, 2012 |
PCT NO: |
PCT/EP2012/056964 |
371 Date: |
February 10, 2014 |
Current U.S.
Class: |
174/84R ;
228/246 |
Current CPC
Class: |
H05K 2201/1031 20130101;
H05K 2201/1028 20130101; Y02P 70/50 20151101; H05K 3/4015 20130101;
H01R 4/02 20130101; H05K 3/3463 20130101; H05K 3/3494 20130101;
H05B 3/84 20130101; H05B 2203/016 20130101; H01L 2924/0002
20130101; H05K 2203/0465 20130101; H01L 2924/0002 20130101; H01L
2924/0001 20130101 |
Class at
Publication: |
174/84.R ;
228/246 |
International
Class: |
H01R 4/02 20060101
H01R004/02 |
Foreign Application Data
Date |
Code |
Application Number |
May 10, 2011 |
EP |
11165501.5 |
May 10, 2011 |
EP |
11165506.4 |
Claims
1. A pane with at least one electrical connection element,
comprising: a substrate, an electrically conductive structure on a
region of the substrate, a connection element, wherein the
connection element contains at least a chromium-containing steel,
and a layer of a solder material, wherein the layer of solder
material electrically connects the connection element to subregions
of the electrically conductive structure.
2. The pane according to claim 1, wherein the substrate contains
glass, polymers, or mixtures of glass and polymers.
3. The pane according to claim 1, wherein a difference between a
coefficient of thermal expansion of the substrate and a coefficient
of thermal expansion of the connection element is less than
5.times.10.sup.-6/.degree. C.
4. The pane according to claim 1, wherein the connection element
contains at least 50 wt.-% to 89.5 wt.-% iron, 10.5 wt.-% to 20
wt.-% chromium, 0 wt.-% to 1 wt.-% carbon, 0 wt.-% to 5 wt.-%
nickel, 0 wt.-% to 2 wt.-% manganese, 0 wt.-% to 2.5 wt.-%
molybdenum, or 0 wt.-% to 1 wt.-% titanium.
5. The pane according to claim 4, wherein the connection element
contains at least 75 wt.-% to 84 wt.-% iron, 16 wt.-% to 18.5 wt.-%
chromium, 0 wt.-% to 0.1 wt.-% carbon, 0 wt.-% to 1 wt.-%
manganese, or 0 wt.-% to 1 wt.-% titanium.
6. The pane according to claim 1, wherein the electrically
conductive structure contains silver.
7. The pane according to claim 1, wherein a layer thickness of the
solder material is less than 3.0.times.10.sup.-4 m.
8. The pane according to claim 1, wherein the solder material
contains tin and i) bismuth, ii) indium, iii) zinc, iv) copper, v)
silver, or compositions of i)-v).
9. The pane according to claim 8, wherein a proportion of tin in
the solder material is 3 wt.-% to 99.5 wt.-% and a proportion of i)
bismuth, ii) indium, iii) zinc, iv) copper, v) silver, or
compositions of i)-v) is 0.5 wt.-% to 97 wt.-%.
10. The pane according to claim 1, wherein the connection element
is coated with nickel, tin, copper, and/or silver.
11. The pane according to claim 10, wherein the connection element
is coated with 0.1 .mu.m to 0.3 .mu.m nickel and/or 3 .mu.m to 20
.mu.m silver.
12. The pane according to claim 1, wherein the connection element
is connected to the subregions of the electrically conductive
structure via at least one contact surface over its entire
surface.
13. The pane according to claim 12, wherein the at least one
contact surface has no corners.
14. A method for production of a pane with at least one electrical
connection element, comprising: a) applying a solder material on at
least one contact surface of a connection element as a platelet
with a fixed layer thickness, volume, shape, and arrangement, b)
applying an electrically conductive structure on a substrate, c)
arranging the connection element with the solder material on an
electrically conductive structure, and d) soldering the connection
element to the electrically conductive structure.
15. A method comprising: using the the pane with at least one
electrical connection element according to claim 1, for vehicles
with electrically conductive structures, preferably with heating
conductors and/or antenna conductors.
16. The pane according to claim 2, wherein the glass is flat glass,
float glass, quartz glass, borosilicate glass, or soda lime
glass.
17. The pane according to claim 2, wherein the polymers are
polyethylene, polypropylene, polycarbonate, or polymethyl
methacrylate.
Description
[0001] The invention relates to a pane with an electrical
connection element and an economical and environmentally friendly
method for its manufacture.
[0002] The invention further relates to a pane with an electrical
connection element for vehicles with electrically conductive
structures such as, for instance, heating conductors or antenna
conductors. The electrically conductive structures are customarily
connected to the onboard electrical system via soldered-on
electrical connection elements. Due to different coefficients of
thermal expansion of the materials used, mechanical stresses occur
that strain the panes and can cause breakage of the pane during
manufacture and operation.
[0003] Lead-containing solders have high ductility that can
compensate the mechanical stresses occurring between an electrical
connection element and the pane by plastic deformation. However,
because of the End of Life Vehicles Directive 2000/53/EC,
lead-containing solders have to be replaced by lead-free solders
within the EC. The directive is referred to, in summary, by the
acronym ELV (End of Life Vehicles). The objective is to ban
extremely problematic components from products resulting from the
massive increase in disposable electronics. The substances affected
are lead, mercury, and cadmium. This relates, among other things,
to the implementation of lead-free soldering materials in
electrical applications on glass and the introduction of
corresponding replacement products.
[0004] EP 1 942 703 A2 discloses an electrical connection element
on panes of vehicles, wherein the difference in the coefficient of
thermal expansion of the pane and the electrical connection element
is <5.times.10.sup.-6/.degree. C. and the connection element
contains predominantly titanium. In order to enable adequate
mechanical stability and processability, it is proposed to use an
excess of solder material. The excess of solder material flows out
from the intermediate space between the connection element and the
electrically conductive structure. The excess of solder material
causes high mechanical stresses in the glass pane. These mechanical
stresses ultimately result in breakage of the pane. In addition,
titanium is poorly solderable. This results in poor adhesion of the
connection element to the pane. The connection element must,
moreover, be connected to the onboard electronics via an
electrically conductive material, for example, copper, by welding,
for instance. Titanium is poorly weldable.
[0005] The object of the present invention is to provide a pane
with an electrical connection element and an economical and
environmentally friendly method for its manufacture, whereby
critical mechanical stresses in the pane are avoided.
[0006] The object of the present invention is, further, to provide
an improved material for the connection element compared to the
prior art, having better availability and better processability,
such as solderability, weldability, and cold formability.
[0007] The object of the present invention is accomplished
according to the invention by a device according to independent
claim 1. Preferred embodiments emerge from the subclaims.
[0008] The pane according to the invention with at least one
connection element comprises the following characteristics:
[0009] a substrate,
[0010] an electrically conductive structure on a region of the
substrate,
[0011] a connection element, wherein the connection element
contains at least chromium, preferably at least a
chromium-containing steel, and
[0012] a layer of a solder material, which electrically connects
the connection element to subregions of the electrically conductive
structure.
[0013] The substrate contains, preferably, glass, particularly
preferably, flat glass, float glass, quartz glass, borosilicate
glass, soda lime glass. In an alternative preferred embodiment, the
substrate contains polymers, particularly preferably, polyethylene,
polypropylene, polycarbonate, polymethyl methacrylate, and/or
mixtures thereof.
[0014] The substrate has a first coefficient of thermal expansion.
The connection element has a second coefficient of thermal
expansion. In an advantageous embodiment of the invention, the
difference between the first and the second coefficient of thermal
expansion is <5.times.10.sup.-6/.degree. C. Because of this,
better adhesion is obtained.
[0015] An electrically conductive structure is applied on the pane.
An electrical connection element is electrically connected by a
soldering material on subregions to the electrically conductive
structure. The solder material flows out with an outflow width of
<1 mm from the intermediate space between the connection element
and the electrically conductive structure.
[0016] In a preferred embodiment, the maximum outflow width is
preferably less than 0.5 mm and, in particular, roughly 0 mm. This
is particularly advantageous with regard to the reduction
mechanical stresses in the pane, the adhesion of the connection
element, and the reduction in the amount of solder.
[0017] The maximum outflow width is defined as the distance between
the outer edges of the connection element and the point of the
solder material crossover, at which the solder material drops below
a layer thickness of 50 .mu.m. The maximum outflow width is
measured on the solidified solder material after the soldering
process.
[0018] A desired maximum outflow width is obtained through a
suitable selection of solder material volume and vertical distance
between the connection element and the electrically conductive
structure, which can be determined by simple experiments. The
vertical distance between the connection element and the
electrically conductive structure can be predefined by an
appropriate process tool, for example, a tool with an integrated
spacer.
[0019] The maximum outflow width can even be negative, i.e., pulled
back into the intermediate space formed by an electrical connection
element and an electrically conductive structure.
[0020] In an advantageous embodiment of the pane according to the
invention, the maximum outflow width is pulled back in a concave
meniscus into the intermediate space formed by the electrical
connection element and the electrically conductive structure. A
concave meniscus is created, for example, by increasing the
vertical distance between the spacer and the conductive structure
during the soldering process, while the solder is still fluid.
[0021] The advantage resides in the reduction of mechanical
stresses in the pane, in particular, in the critical region present
with a large solder material crossover.
[0022] The first coefficient of thermal expansion is preferably
from 8.times.10.sup.-6/.degree. C. to 9.times.10.sup.-6/.degree. C.
The substrate is preferably glass that has, preferably, a
coefficient of thermal expansion from 8.3.times.10.sup.-6/.degree.
C. to 9.times.10.sup.-6/.degree. C. in a temperature range from
0.degree. C. to 300.degree. C.
[0023] The second coefficient of thermal expansion is preferably
from 9.times.10.sup.-6/.degree. C. to 13.times.10.sup.-6/.degree.
C., particularly preferably from 10.times.10.sup.-6/.degree. C. to
11.5.times.10.sup.-6/.degree. C. in a temperature range from
0.degree. C. to 300.degree. C.
[0024] The electrically conductive structure according to the
invention has, preferably, a layer thickness of 5 .mu.m to 40
.mu.m, particularly preferably from 5 .mu.m to 20 .mu.m, very
particularly preferably, from 8 .mu.m to 15 .mu.m and, most
particularly, from 10 .mu.m to 12 .mu.m. The electrically
conductive structure according to the invention contains,
preferably, silver, particularly preferably, silver particles and
glass frits.
[0025] The layer thickness of the solder according to the invention
is <3.0.times.10.sup.-4 m.
[0026] The solder material is preferably leadfree, i.e., contains
no lead. This is particularly advantageous with regard to the
environmental impact of the pane with an electrical connection
element according to the invention. Leadfree solder materials
typically have less ductility than lead-containing solder
materials, such that mechanical stresses between a connection
element and a pane can be less well compensated. However, it has
been demonstrated that critical mechanical stresses can be avoided
by means of the connection element according to the invention. The
solder material according to the invention contains, preferably,
tin and bismuth, indium, zinc, copper, silver, or compositions
thereof. The proportion of tin in the solder composition according
to the invention is from 3 wt.-% to 99.5 wt.-%, preferably from 10
wt.-% to 95.5 wt.-%, particularly preferably from 15 wt.-% to 60
wt.-%. The proportion of bismuth, indium, zinc, copper, silver, or
compositions thereof in the solder composition according to the
invention is from 0.5 wt.-% to 97 wt.-%, preferably 10 wt.-% to 67
wt.-%, whereby the proportion of bismuth, indium, zinc, copper, or
silver can be 0 wt.-%. The solder composition according to the
invention can contain nickel, germanium, aluminum, or phosphorus at
a proportion of 0 wt.-% to 5 wt.-%. The solder composition
according to the invention contains, very particularly preferably,
Bi40Sn57Ag3, Sn40Bi57Ag3, Bi59Sn40Ag1, Bi57Sn42Ag1, In97Ag3,
Sn95.5Ag3.8Cu0.7, Bi67In33, Bi33In50Sn17, Sn77.2In20Ag2.8,
Sn95Ag4Cu1, Sn99Cu1, Sn96.5Ag3.5, or mixtures thereof.
[0027] The connection element according to the invention contains
preferably at least 50 wt.-% to 89.5 wt.-% iron, 10.5 wt.-% to 20
wt.-% chromium, 0 wt.-% to 1 wt.-% carbon, 0 wt.-% to 5 wt.-%
nickel, 0 wt.-% to 2 wt.-% manganese, 0 wt.-% to 2.5 wt.-%
molybdenum, and/or 0 wt.-% to 1 wt.-% titanium. In addition, the
connection element can contain admixtures of other elements,
including vanadium, aluminum, niobium, and nitrogen.
[0028] The connection element according to the invention can also
contain at least 66.5 wt.-% to 89.5 wt.-% iron, 10.5 wt.-% to 20
wt.-% chromium, 0 wt.-% to 1 wt.-% carbon, 0 wt.-% to 5 wt.-%
nickel, 0 wt.-% to 2 wt.-% manganese, 0 wt.-% to 2.5 wt.-%
molybdenum, 0 wt.-% to 2 wt.-% niobium, and/or 0 wt.-% to 1 wt.-%
titanium. In addition, the connection element can contain
admixtures of other elements, including vanadium, aluminum, and
nitrogen.
[0029] In another preferred embodiment, the connection element
according to the invention contains at least 65 wt.-% to 89.5 wt.-%
iron, 10.5 wt.-% to 20 wt.-% chromium, 0 wt.-% to 0.5 wt.-% carbon,
0 wt.-% to 2.5 wt.-% nickel, 0 wt.-% to 1 wt.-% manganese, 0 wt.-%
to 1 wt.-% molybdenum, and/or 0 wt.-% to 1 wt.-% titanium. In
addition, the connection element can contain admixtures of other
elements, including vanadium, aluminum, niobium, and nitrogen.
[0030] The connection element according to the invention can also
contain at least 73 wt.-% to 89.5 wt.-% iron, 10.5 wt.-% to 20
wt.-% chromium, 0 wt.-% to 0.5 wt.-% carbon, 0 wt.-% to 2.5 wt.-%
nickel, 0 wt.-% to 1 wt.-% manganese, 0 wt.-% to 1 wt.-%
molybdenum, 0 wt.-% to 1 wt.-% niobium, and/or 0 wt.-% to 1 wt.-%
titanium. In addition, the connection element can contain
admixtures of other elements, including vanadium, aluminum, and
nitrogen.
[0031] In another, particularly preferred embodiment, the
connection element according to the invention contains at least 75
wt.-% to 84 wt.-% iron, 16 wt.-% to 18.5 wt.-% chromium, 0 wt.-% to
0.1 wt.-% carbon, 0 wt.-% to 1 wt.-% manganese, and/or 0 wt.-% to 1
wt.-% titanium. In addition, the connection element can contain
admixtures of other elements, including vanadium, aluminum,
niobium, and nitrogen.
[0032] The connection element according to the invention can also
contain at least 78.5 wt.-% to 84 wt.-% iron, 16 wt.-% to 18.5
wt.-% chromium, 0 wt.-% to 0.1 wt.-% carbon, 0 wt.-% to 1 wt.-%
manganese, 0 wt.-% to 1 wt.-% niobium, and/or 0 wt.-% to 1 wt.-%
titanium. In addition, the connection element can contain
admixtures of other elements, including vanadium, aluminum, and
nitrogen.
[0033] The connection element according to the invention is coated,
preferably, with nickel, tin, copper, and/or silver. The connection
element according to the invention is particularly preferably
provided with an adhesion-promoting layer, preferably made of
nickel and/or copper, and, additionally, with a solderable layer,
preferably made of silver. The connection element according to the
invention is coated, very particularly preferably, with 0.1 .mu.m
to 0.3 .mu.m nickel and/or 3 .mu.m to 20 .mu.m silver. The
connection element can be plated with nickel, tin, copper, and/or
silver. Nickel and silver improve the current carrying capacity and
corrosion stability of the connection element and the wetting with
the solder material.
[0034] The connection element according to the invention contains
preferably a chromium-containing steel with a proportion of
chromium greater than or equal to 10.5 wt.-% and a coefficient of
thermal expansion of 9.times.10.sup.-6/.degree. C. to
13.times.10.sup.-6/.degree. C. Further alloy components such as
molybdenum, manganese, or niobium result in improved corrosion
stability or altered mechanical properties, such as tensile
strength or cold formability.
[0035] The advantage of connection elements made of
chromium-containing steel compared to connection elements according
to the prior art made of titanium resides in the better
solderability. It results from the higher thermal conductivity of
25 W/mK to 30 W/mK compared to the thermal conductivity of titanium
of 22 W/mK. The higher thermal conductivity results in a more
uniform heating of the connection element during the soldering
process, by means of which the pointwise formation of particularly
hot sites ("hot spots") is avoided. These sites are starting points
for mechanical stresses and subsequent damage of the pane. Improved
adhesion of the connection element to the pane results, in
particular with the use of a leadfree solder material that can
compensate mechanical stresses less well due to its lower ductility
compared to lead-containing solder materials. Chromium-containing
steel is, moreover, well weldable. With it, better connecting of
the connection element to the onboard electronics via an
electrically conductive material, e.g., copper, by welding, is
possible. Due to the better cold formability, the connection
element can also be better crimped with the electrically conductive
material. Chromium-containing steel is, moreover, more
available.
[0036] A further advantage of connection elements made of
chromium-containing steel resides in the high rigidity compared to
many conventional connection elements. Because of it, the
connection element can be less readily deformed, for example, under
load from pulling on a wire connected to the connection element.
Such a deformation results in a load on the connection between a
connection element and an electrically conductive structure via the
solder material. In particular, with leadfree solder materials,
such a load must be avoided. The load can be less well compensated
as a result of the lower ductility of the leadfree solder material
compared to lead-containing solder materials, which can lead to
damage to the pane.
[0037] The chromium-containing steel can also be welded, crimped,
or glued as a compensation plate on a connection element made, for
example, of steel, aluminum, titaniumium, copper. As a bimetal,
favorable expansion behavior of the connection element relative to
the glass expansion can be obtained. The compensation plate is
preferably hat-shaped.
[0038] The electrical connection element contains, on the surface
facing the solder material, a coating that contains copper, zinc,
tin, silver, gold, or alloys or layers thereof, preferably silver.
This prevents a spreading of the solder material out beyond the
coating and limits the outflow width.
[0039] The electrical connection element can be designed in the
form of a bridge with at least two contact surfaces, but also as a
connection element with one contact surface.
[0040] The connection elements are, in the plan view, for example,
preferably 1 mm to 50 mm long and wide and, particularly preferably
3 mm to 30 mm long and wide and, very particularly preferably 2 mm
to 5 mm wide and 12 mm to 24 mm long.
[0041] The shape of the electrical connection element can form
solder depots in the intermediate space of the connection element
and the electrically conductive structure. The solder depots and
wetting properties of the solder on the connection element prevent
the outflow of the solder material from the intermediate space. The
solder depots can be rectangular, rounded, or polygonal in
design.
[0042] The distribution of the soldering heat and, thus, the
distribution of the solder material during the soldering process
can be defined by the shape of the connection element. Solder
material flows to the warmest point. For example, the bridge can
have a single or double hat shape in order to distribute the heat
advantageously in the connection element during the soldering
process.
[0043] The introduction of the energy during the electrical
connecting of an electrical connection and an electrically
conductive structure occurs preferably by means of punches,
thermodes, piston soldering, preferably laser soldering, hot air
soldering, induction soldering, resistance soldering, and/or with
ultrasound.
[0044] The object of the invention is further accomplished through
a method for production of a pane with at least one connection
element, wherein
[0045] a) solder material is applied on the contact surfaces of the
connection element as a platelet with a fixed layer thickness,
volume, shape, and arrangement,
[0046] b) an electrically conductive structure is applied to a
substrate,
[0047] c) the connection element with the solder material is
arranged on the electrically conductive structure, and
[0048] d) the connection element is soldered to the electrically
conductive structure.
[0049] The solder material is preferably applied in advance to the
connection elements, preferably as a platelet with a fixed layer
thickness, volume, shape, and arrangement on the connection
element.
[0050] The connection element can, for example, be welded or
crimped to a sheet, a braided wire, a mesh made, for example, of
copper and connected to the onboard electrical system.
[0051] The connection element is preferably used in heated panes or
in panes with antennas in buildings, in particular, in automobiles,
railroads, aircraft, or watercraft. the connection element serves
to connect the conducting structures of the pane to electrical
systems that are arranged outside the pane. The electrical systems
are amplifiers, control units, or voltage sources.
[0052] A preferred embodiment of the invention is a pane with a
connection element, wherein the contact surface of the connection
element has no corners. The electrical connection element is
connected over its entire surface to a subregion of the
electrically conductive structure via one contact surface. The
contact surface can have an oval, preferably an elliptical, and, in
particular, a circular structure. Alternatively, the contact
surface can have a convex polygonal shape, preferably a rectangular
shape, with rounded corners. The rounded corners have a radius of
curvature of r>0.5 mm, preferably of r>1 mm.
[0053] The invention is explained in detail with reference to
drawings and exemplary embodiments. They depict:
[0054] FIG. 1 a perspective view of a first embodiment of the pane
according to the invention,
[0055] FIG. 1a a perspective view of an alternative embodiment of
the pane according to the invention,
[0056] FIG. 2 a cross-section A-A' through the pane of FIG. 1,
[0057] FIG. 3 a cross-section through an alternative pane according
to the invention,
[0058] FIG. 4 a cross-section through another alternative pane
according to the invention,
[0059] FIG. 5 a cross-section through another alternative pane
according to the invention,
[0060] FIG. 6 a perspective view of an alternative embodiment of
the pane according to the invention,
[0061] FIG. 7 a cross-section B-B' through the pane of FIG. 6,
[0062] FIG. 8 a cross-section C-C' through the pane of FIG. 1,
[0063] FIG. 9 a cross-section D-D' through the pane of FIG. 1a,
[0064] FIG. 9a a cross-section through an alternative embodiment of
the pane according to the invention,
[0065] FIG. 9b a plan view of an alternative embodiment of the
connection element,
[0066] FIG. 10 a plan view of an alternative embodiment of the of
the pane according to the invention with an elliptical connection
element,
[0067] FIG. 11 a cross-section E-E' through the pane of FIG.
10,
[0068] FIG. 12 a cross-section through an alternative pane
according to the invention,
[0069] FIG. 13 a cross-section through another alternative pane
according to the invention,
[0070] FIG. 14 a plan view of an alternative embodiment of the
connection element,
[0071] FIG. 15 a plan view of another alternative embodiment of the
connection element,
[0072] FIG. 16 a plan view of another alternative embodiment of the
connection element,
[0073] FIG. 17 a side view of the connection element of FIG. 16,
and
[0074] FIG. 18 a cross-section through another alternative pane
according to the invention with a curved connection element,
[0075] FIG. 19 a perspective view of another alternative embodiment
of the connection element, and
[0076] FIG. 20 a detailed flow chart of the method according to the
invention.
[0077] FIG. 1, FIG. 2, and FIG. 8 show, in each case, a detail of a
heatable pane 1 according to the invention in the region of the
electrical connection element 3. The pane 1 is a 3-mm-thick
thermally prestressed single-pane safety glass made of soda lime
glass. The pane 1 has a width of 150 cm and a height of 80 cm. An
electrically conductive structure 2 in the form of a heating
conductor structure 2 is printed on the pane 1. The electrically
conductive structure 2 contains silver particles and glass frits.
In the edge region of the pane 1, the electrically conductive
structure 2 is widened to a width of 10 mm and forms a contact
surface for the electrical connection element 3. In the edge region
of the pane 1, there is also a covering serigraph (not shown). In
the region of the contact surface 8 between the electrical
connection element 3 and the electrically conductive structure 2,
solder material 4 is applied, which effects a durable electrical
and mechanical connection between the electrical connection element
3 and the electrically conductive structure 2. The solder material
4 contains 57 wt.-% bismuth, 40 wt.-% tin, and 3 wt.-% silver. The
solder material 4 is arranged through a predefined volume and shape
completely between the electrical connection element 3 and the
electrically conductive structure 2. The solder material 4 has a
thickness of 250 .mu.m. The electrical connection element 3 is made
from steel of the material number 1.4509 in accordance with EN 10
088-2 (ThyssenKrupp Nirosta.RTM. 4509) with a coefficient of
thermal expansion of 10.0.times.10.sup.-6/.degree. C. The
electrical connection element 3 is designed in the form of a bridge
and has a width of 4 mm and a length of 24 mm.
[0078] Steel of the material number 1.4509 in accordance with EN 10
088-2 has good cold forming properties and good welding properties
with all methods except gas welding. The steel is used for
construction of sound suppressor systems and exhaust gas
detoxification systems and is particularly suited for that due to
its scaling resistance to more than 950.degree. C. and corrosion
resistance against the stresses occurring in the exhaust gas
system. However, other chromium-containing steels can be used for
the connection element 3. One alternative particularly suitable
steel is, for example, material number 1.4016 in accordance with EN
10 088-2.
[0079] FIG. 1a and FIG. 9 depict, in each case, a detail of an
alternative embodiment of the heatable pane 1 according to the
invention in the region of the electrical connection element 3. The
region 7 of the connection element 3 in the form of a bridge is
formed at an angle to the surface of the pane. By this means, due
to the capillary effect, a thicker layer of solder material 4 is
obtained in the volume that is delimited by the electrically
conductive structure 2 and region 7 of the connection element. The
solder material outflow on the outer edges of the connection
element is thus reduced, advantageously resulting in a reduction of
the mechanical stresses in the pane. This is particularly
advantageous with the use of a leadfree solder material that can
compensate chemical stresses less well due to its lower ductility
compared to lead-containing solder materials. The height-adapting
region 7 of the connection element 3 in the form of a bridge does
not necessarily have to be configured as a flat segment, but can,
instead, also be curved. The angle between the surface of the
substrate 1 and each of the tangential planes of the surfaces of
the region 7 facing the substrate 1 is preferably less than
90.degree., particularly preferably between 2.degree. and
75.degree., very particularly preferably between 5.degree. and
50.degree..
[0080] FIG. 3 depicts, in continuation of the exemplary embodiment
of FIGS. 1 and 2, an alternative embodiment of the connection
element 3 according to the invention. The electrical connection
element 3 is provided on the surface facing the solder material 4
with a silver-containing coating 5. This prevents spreading of the
solder material out beyond the coating 5 and limits the outflow
width b. In another embodiment, an adhesion-promoting layer made,
for example, of nickel and/or copper, can be located between the
connection element 3 and the silver-containing layer 5. The outflow
width b of the solder material 4 is less than 1 mm. No critical
mechanical stresses are observed in the pane 1 due to the
arrangement of the solder material 4. The connection of the pane 1
to the electrical connection element 3 via the electrically
conductive structure 2 is durably stable.
[0081] FIG. 4 depicts, in continuation of the exemplary embodiment
of FIGS. 1 and 2, another alternative embodiment of the connection
element 3 according to the invention. The electrical connection
element 3 contains, on the surface facing the solder material 4, a
recess with a depth of 250 .mu.m that forms a solder depot for the
solder material 4. It is possible to completely prevent outflow of
the solder material 4 from the intermediate space. The thermal
stresses in the pane 1 are noncritical and a durable electrical and
mechanical connection is provided between the connection element 3
and the pane 1 via the electrically conductive structure 2.
[0082] FIG. 5 depicts, in continuation of the exemplary embodiment
of FIGS. 1 and 2, another alternative embodiment of the connection
element 3 according to the invention. The electrical connection
element 3 is bent upward on the edge regions. The height of the
upward bend of the edge region of the glass pane 1 is a maximum of
400 .mu.m. This forms a space for the solder material 4. The
predefined solder material 4 forms a concave meniscus between the
electrical connection element 3 and the electrically conductive
structure 2. It is possible to completely prevent outflow of solder
material 4 from the intermediate space. The outflow width b, at
roughly 0, is less than zero, largely because of the meniscus
formed. The thermal stresses in the pane 1 are noncritical, and a
durable electrical and mechanical connection is provided between
the connection element 3 and the pane 1 via the electrically
conductive structure 2.
[0083] FIG. 6 and FIG. 7 depict, in each case, a detail of another
embodiment of the pane 1 according to the invention with connection
element 3 in the form of a bridge. The connection element 3
contains an iron-containing alloy with a coefficient of thermal
expansion of 8.times.10.sup.-6/.degree. C. The material thickness
is 2 mm. In the region of the contact surface 8 of the connection
element 3 with the electrically conductive structure 2, hat-shaped
compensation members 6 are applied with chromium-containing steel
of the material number 1.4509 in accordance with EN 10 088-2
(ThyssenKrupp Nirosta.RTM. 4509). The maximum layer thickness of
the hat-shaped compensation members 6 is 4 mm. By means of the
compensation members, it is possible to adapt the coefficients of
thermal expansion of the connection element 3 to the requirements
of the pane 1 and of the solder material 4. The hat-shaped
compensation members 6 result in improved heat flow during the
production of the solder connection 4. The heating occurs primarily
in the center of the contact surface 8. It is possible to further
reduce the outflow width b of the solder material 4. Because of the
low outflow width b of <1 mm and the adapted coefficient of
expansion, it is possible to further reduce the thermal stresses in
the pane 1. The thermal stresses in the pane 1 are noncritical, and
a durable electrical and mechanical connection is provided between
the connection element 3 and the pane 1 via the electrically
conductive structure 2.
[0084] FIG. 9a depicts, in continuation of the exemplary embodiment
of FIGS. 1a and 9, an alternative embodiment of the connection
element 3 according to the invention. On each of the surfaces of
the flat foot region of the connection element 3 facing away from
the substrate 1 opposite the contact surface 8, a contact bump 12
is arranged. The contact bumps 12 are formed, in the embodiment
shown, as hemispheres and have a height of 2.5.times.10.sup.-4 m
and a width of 5.times.10.sup.-4 m. The centers of the contact
bumps 12 are arranged roughly in the geometric center of the
surfaces of the flat foot regions of the connection element 3
facing away from the substrate 1. Because of their convex surface,
the contact bumps 12 enable an advantageously improved soldering of
the connection element to the electrically conductive structure 2.
For the soldering, electrodes whose contact side is flat can be
used. The electrode surface is brought into contact with the
contact bump 12, with the contact region between the electrode
surface and the contact bump 12 forming the soldering point. The
position of the soldering point is thus determined preferably by
the point on the convex surface of the contact bump 12 that has the
greatest vertical distance from the surface of the substrate 1. The
position of the soldering point is independent of the position of
the solder electrode on the connection element 3. That is
particularly advantageous with regard to a reproducible, uniform
heat distribution during the soldering process.
[0085] The heat distribution during the soldering process is
determined by the position, the size, the arrangement, and the
geometry of the contact bump 12. In alternative embodiments, the
contact bump 12 can be shaped, for example, as a segment of a
rotational ellipsoid or as a cuboid, with the surface of the cuboid
turned away from the substrate curved convexly. The contact bumps
12 preferably have a height of 0.1 mm to 2 mm, particularly
preferably of 0.2 mm to 1 mm. The length and width of the contact
bumps 12 is preferably between 0.1 and 5 mm, very particularly
preferably between 0.4 mm and 3 mm.
[0086] Spacers 11 are arranged on each of the contact surfaces 8.
Three spacers 11, for example, of which one spacer 11 is
discernible in the cross-section depicted in the figure, can be
arranged on each contact surface 8. The spacers 11 are shaped as
hemispheres and have a height of 2.5.times.10.sup.-4 m and a width
of 5.times.10.sup.-4 m. The spacers 11 can, in alternative
embodiments, also be designed as a cube, as a pyramid, or as a
segment of a rotational ellipsoid and preferably have a width of
0.5.times.10.sup.-4 m to 10.times.10.sup.-4 m and a height of
0.5.times.10.sup.-4 m to 5.times.10.sup.-4 m, particularly
preferably of 1.times.10.sup.-4 m to 3.times.10.sup.-4 m. By means
of the spacers 11, the formation of a uniform layer of solder
material 4 is favored. That is particularly advantageous with
regard to the adhesion of the connection element 3.
[0087] The contact bumps 12 and spacers 11 can, in an advantageous
embodiment, be formed in one piece with the connection element 3.
The contact bumps 12 and the spacers 11 can, for example, be formed
by reshaping a connection element 3 with a flat surface in the
initial state on the surface, for example, by stamping or deep
drawing. In the process, a corresponding depression can be created
on the surface of the connection element 3 opposite the contact
bump 12 or the spacer 11.
[0088] By means of the contact bumps 12 and the spacers 11, a
homogeneous, uniformly thick, and uniformly fuzed layer of the
solder material 4 is obtained. Thus, mechanical stresses between
the connection element 3 and substrate 1 can be reduced. This is
particularly advantageous with the use of a leadfree solder
material that can compensate mechanical stresses less well due to
its lower ductility compared to lead-containing solder
materials.
[0089] FIG. 9b depicts, in continuation of the exemplary embodiment
of FIGS. 1a and 9, a plan view of an alternative embodiment of the
connection element 3 according to the invention. The connection
element 3 is designed in the form of a bridge and has a
cross-section in accordance with FIG. 9. The boundaries between the
flat subsections are indicated in the plan view by dotted lines.
The flat foot regions of the connection element 3, on the bottom of
which the contact surfaces 8 are arranged, have a width of 8 mm and
are twice as wide as the bridge region between the foot regions. It
has surprisingly been demonstrated that foot regions that are
designed wider than the bridge region result in a reduction of
mechanical stresses in the pane 1. The width of the foot regions is
preferably from 150% to 300% of the width of the bridge region.
[0090] FIG. 10 and FIG. 11 show, in each case, a detail of another
embodiment of the heatable pane 1 according to the invention in the
region of the electrical connection element 3. An outflow of the
solder material 4 from the intermediate space between the
electrical connection element 3 and the electrically conductive
structure 2, which exceeds a layer thickness t of 50 .mu.m, is
observed to a maximum outflow width of b=0.5 mm. The electrical
connection element 3 is made from steel of the material number
1.4509 in accordance with EN 10 088-2 (ThyssenKrupp Nirosta.RTM.
4509). The electrical connection element 3 is designed with an
elliptical base surface. The length of the major axis is 12 mm; the
length of the minor axis, 5 mm. The material thickness of the
connection element 3 is 0.8 mm. No critical mechanical stresses are
observed in the pane 1 due to the arrangement of the solder
material 4, predefined by the connection element 3 and the
electrically conductive structure 2. The connection of the pane 1
to the electrical connection element 3 via the electrically
conductive structure 2 is durably stable.
[0091] FIG. 12 shows, in continuation of the exemplary embodiment
of FIGS. 10 and 11, an alternative embodiment of the connection
element 3 according to the invention. The electrical connection
element 3 is provided on the surface facing the solder material 4
with a silver-containing coating 5. This prevents spreading of the
solder material out beyond the coating 5 and limits the outflow
width b. The outflow width b of the solder material 4 is less than
1 mm. No critical mechanical stresses are observed in the pane 1
due to the arrangement of the solder material 4. The connection of
the pane 1 to the electrical connection element 3 via the
electrically conductive structure 2 is durably stable.
[0092] FIG. 13 shows, in continuation of the exemplary embodiment
of FIGS. 10 and 11, another alternative embodiment of the pane 1
according to the invention with a connection element 3 with an
elliptical base surface. The connection element 3 contains an
iron-containing alloy with a coefficient of thermal expansion of
8.times.10.sup.-6/.degree. C. The material thickness is 2 mm. In
the region of the contact surface 8 of the connection element 3
with the electrically conductive structure 2, a hat-shaped
compensation member 6 is applied with chromium-containing steel of
the material number 1.4509 in accordance with EN 10 088-2
(ThyssenKrupp Nirosta.RTM. 4509). The maximum layer thickness of
the hat-shaped compensation member 6 is 4 mm. By means of the
compensation member, it is possible to adapt the coefficients of
thermal expansion of the connection element 3 to the requirements
of the pane 1 and of the solder material 4. The hat-shaped
compensation members 6 results in improved heat flow during the
production of the solder connection 4. The heating occurs primarily
in the center of the contact surface 8. It is possible to further
reduce the outflow width b of the solder material 4. Because of the
low outflow width b of <1 mm and the adapted coefficient of
expansion, it is possible to further reduce the thermal stresses in
the pane 1. The thermal stresses in the pane 1 are noncritical, and
a durable electrical and mechanical connection is provided between
the connection element 3 and the pane 1 via the electrically
conductive structure 2.
[0093] FIG. 14 depicts a plan view of an alternative embodiment of
the connection element 3 according to the invention. The connection
element 3 is designed as a rectangle and has a width of 5 mm and a
length of 14 mm. The corners of the rectangle are in each case
rounded with a circular segment with a radius curvature r of 1 mm,
for example. Furthermore, a connection cable 18 is welded via a
welding region 17 to the connection element 3. The welding region
17 has a width of 3 mm and a length of 6 mm. The connection cable
18 is a woven cable made of thin, tin-plated copper wires. Stranded
wire cables or wires can also be used as the connection cable 18.
Alternatively, metal sleeves, plug connectors, or crimp connections
can also be electrically conductively connected to the connection
element 3. In particular, the connection element 3 can also be
designed as a one-part or multi-part clamping sleeve or crimp
element.
[0094] FIG. 15 depicts a plan view of another alternative
embodiment of the connection element 3 according to the invention.
The connection element 3 is designed as a rectangle, with the two
short sides of the rectangle designed as semicircles. The
connection element has a width of 5 mm and a length of 14 mm. The
welding region 17 has a width of 3 mm and a length of 6 mm.
[0095] FIG. 16 and FIG. 17 depict another alternative embodiment of
the connection element 3 according to the invention with a
connecting tab 19. The contact surface 8 of the connection element
3 is designed as a circle. The radius of the circle is 4 mm. The
connecting tab 19 is connected via a welding region 17 to a
connection cable 18. Alternatively, the connecting tab 19 can also
be designed as a flat plug as well as a clamping sleeve or crimp
connector. The connecting tab 19 has, in this embodiment, two
notches 20, 20'. These notches 20, 20' serve to reduce the material
of the connecting tab 19. This results in a spring effect and thus
to the mitigation of forces that are transferred via the connection
cable 18 to the solder contact.
[0096] FIG. 18 depicts a cross-section through another alternative
embodiment of a connection element 3 according to the invention.
The connection element 3 has a curve 23 in the center. In the
region of the curve 23, the solder material 4 is thickened.
[0097] FIG. 19 depicts a perspective view of an alternative
embodiment of the connection element 3 according to the invention.
The connection element 3 is designed in the form of a bridge and
has a first and second flat foot region with, for example, a length
of 7 mm and a width of 5 mm, on the bottom of which the two contact
surfaces 8 are arranged. The flat foot regions are connected to
each other via a bridge region that comprises a flat section with,
for example, a length of 12 mm and a width of 10 mm. The flat
section of the bridge region has a production-related indentation
10. The indentation 10 runs all the way to the edge of the flat
section of the bridge region, to which the first foot region is
connected via a height-adapting transition region 7. The
indentation 10 corresponds in shape and size to the section of the
connection element 3 from the first foot region and the
height-adapting transition region 7. The contact surfaces 8 have a
rectangular shape, with the two corners turned away from the bridge
region beveled in each case. By means of the beveling, angles that
are too small, in particular 90.degree.-angles along the
surrounding side edges of the contact surfaces 8 are avoided. It
has been demonstrated that mechanical stresses in the pane can thus
be reduced.
[0098] The connection element 3 includes a plug connector 9
arranged on the bridge region. The plug connector 9 is connected,
on the side edge of the flat section of the bridge region facing
the first foot region, to the flat section of the bridge region.
The plug connector 9 is designed as a standardized tab connector to
which the coupling of a connection cable (not shown) to the onboard
electronics, for instance, can be attached.
[0099] The particular advantage of the embodiment of the invention
resides in simple production of the connection element 3,
providing, at the same time, a convenient interface for electrical
contacting (plug connector 9). The foot regions, the bridge region,
and the plug connector 9 are formed in one piece. The connection
element 3 is provided in a flat initial state, in which the
sections provided as the first foot region and height-adapting
transition region 7 are arranged inside the indentation 10. In the
initial state, the plug connector 9 is arranged in the same plane
as the flat section of the bridge region. The region provided as
the first foot region and the height-adapting transition region 7
can be separated from the flat section of the bridge region, for
example, by punching, laser beam machining, or waterjet machining,
with a connection remaining between the height-adapting transition
region 7 and the flat section of the bridge region via the
connecting edge. The plug connector 9 is bent around the connecting
line between the plug connector 9 and the flat section of the
bridge region into the position depicted, with the surface that
faces upward in the initial state then facing the bridge region.
The first foot region and the height-adapting transition region 7
are bent above the connecting line between the height-adapting
transition region 7 and the flat section of the bridge region into
the position depicted, with the surface that faces upward in the
initial state then forming the bottom side of the first foot region
and the height-adapting transition region 7. The indentation 10 is
formed by the bending of the first foot region. The second foot
region and the corresponding height-adapting transition region 7
are also bent from the flat initial state into the position
depicted.
[0100] FIG. 20 depicts in detail a method according to the
invention for manufacture of a pane 1 with an electrical connection
element 3. An example of the method according to the invention for
manufacture of a pane with an electrical connection element 3 is
presented there. As the first step, it is necessary to portion the
solder material 4 according to shape and volume. The portioned
solder material 4 is arranged on the contact surfaces 8 of the
electrical connection element 3. The electrical connection element
3 is arranged with the solder material 4 on the electrically
conductive structure 2. A durable connection of the electrical
connection element 3 to the electrically conductive structure 2
and, thus, to the pane 1 takes place through the input of
energy.
EXAMPLE
[0101] Test specimens were produced with the pane 1 (thickness 3
mm, width 150 cm, and height 80 cm), the electrically conductive
structure 2 in the form of a heating conductor structure, the
electrical connection element 3 according to FIG. 1, the silver
layer 5 on the contact surfaces 8 of the connection element 3, and
the solder material 4. The material thickness of the connection
element 3 was 0.8 mm. The contact surface 8 of the connection
element 3 had a width of 4 mm and a length of 4 mm. The solder
material 4 was applied in advance as a platelet with fixed layer
thickness, volume, and shape on the contact surface 8 of the
connection element 3. The connection element 3 was applied with the
solder material 4 applied on the electrically conductive structure
2. The connection element 3 was soldered onto the electrically
conductive structure 2 at a temperature of 200.degree. C. and a
processing time of 2 seconds. Outflow of the solder material 4 from
the intermediate space between the electrical connection element 3
and the electrically conductive structure 2, which exceeded a layer
thickness t of 50 .mu.m, was observed only to a maximum outflow
width of b=0.5 mm. The dimensions and compositions of the
electrical connection element 3, the silver layer 5 on the contact
surfaces 8 of the connection element 3, and the solder material 4
are found in Table 1. No critical mechanical stresses were observed
in the pane 1 due to the arrangement of the solder material 4,
predefined by the connection element 3 and the electrically
conductive structure 2. The connection of the pane 1 to the
electrical connection element 3 via the electrically conductive
structure 2 was durably stable.
[0102] Due to the capillary effect, the connection element 3 of
FIG. 1a exhibited better adhesion between the connection element 3
and the substrate 1. Due to the arrangement of the solder material
4, no critical mechanical stresses were observed in the pane 1. The
connection of the pane 1 to the electrical connection element 3 via
the electrically conductive structure 2 was durably stable.
[0103] With all specimens, it was possible to observe, with a
temperature difference from +80.degree. C. to -30.degree. C., that
no glass substrate 1 broke or showed damage. It was possible to
demonstrate that, shortly after soldering, these panes 1 with the
soldered connection element 3 were stable against a sudden
temperature drop.
TABLE-US-00001 TABLE 1 Components Material Example Connection Steel
of material no. 1.4509 in accordance element 3 with EN 10 088-2
with the composition: Iron (wt.-%) 78.87 Carbon (wt.-%) 0.03
Chromium (wt.-%) 18.5 Titanium (wt.-%) 0.6 Niobium (wt.-%) 1
Manganese (wt.-%) 1 CTE (coefficient of thermal expansion) 10
(10.sup.-6/.degree. C. for 0.degree. C.-100.degree. C.) Difference
between CTE of the connection 1.7 element and substrate
(10.sup.-6/.degree. C. for 0.degree. C.-100.degree. C.) Thermal
conductivity (W/mK for 20.degree. C.) 25 Thickness of the
connection element (m) 8.0 .times. 10.sup.-4 Wetting layer 5 Silver
(wt.-%) 100 Thickness of the layer (m) 7.0 .times. 10.sup.-6 Solder
Tin (wt.-%) 40 material 4 Bismuth (wt.-%) 57 Silver (wt.-%) 3
Thickness of the solder layer in (m) 250 .times. 10.sup.-6 The
thickness of the wetting layer and the 257 .times. 10.sup.-6 solder
layer (m) Glass CTE (10.sup.-6/.degree. C. for 0.degree.
C.-320.degree. C.) 8.3 substrate 1 (Soda lime glass)
Comparative Example
[0104] The comparative example was carried out the same as the
example. The difference resided in the use of a different material
for the connection element 3. The connection element 3 was 100
wt.-% titanium. The connection element 3 thus had lower thermal
conductivity, a lower coefficient of thermal expansion, and a
smaller difference of the coefficients of thermal expansion between
connection element 3 and substrate 1. The dimensions and components
of the electrical connection element 3, the metal layer on the
contact surfaces 8 of the connection element 3 and the solder
material 4 are found in Table 2. The connection element 3 was
soldered to the electrically conductive structure 2 in accordance
with conventional methods by means of the solder material 4. With
the outflow of the solder material 4 from the intermediate space
between the electrical connection element 3 and the electrically
conductive structure 2, which exceeded a layer thickness t of 50
.mu.m, an average outflow width b=2 mm to 3 mm was obtained. The
lower thermal conductivity of the material for the connection
element resulted, in the comparative example, in a less uniform
heating of the connection element during the soldering process.
[0105] With a sudden temperature difference from +80.degree. C. to
-30.degree. C., it was observed that the glass substrates 1 had
major damage shortly after soldering.
TABLE-US-00002 TABLE 2 Comparative Components Material example
Connection Titanium (wt.-%) 100 element 3 CTE (coefficient of
thermal expansion) 8.80 (10.sup.-6/.degree. C. for 0.degree.
C.-100.degree. C.) Difference between CTE of the connection 0.5
element and substrate (10.sup.-6/.degree. C. for 0.degree.
C.-100.degree. C.) Thermal conductivity (W/mK for 20.degree. C.) 22
Thickness of the connection element (m) 8.0 .times. 10.sup.-4
Wetting layer 5 Silver (wt.-%) 100 Thickness of the layer (m) 7.0
.times. 10.sup.-6 Solder Tin (wt.-%) 40 material 4 Bismuth (wt.-%)
57 Silver (wt.-%) 3 Thickness of the solder layer in (m) 250
.times. 10.sup.-6 The thickness of the wetting layer and the 257
.times. 10.sup.-6 solder layer (m) Glass CTE (10.sup.-6/.degree. C.
for 0.degree. C.-320.degree. C.) 8.3 substrate 1 (Soda lime
glass)
[0106] The differences from Tables 1 and 2 above and the advantages
of the connection element 3 according to the invention are found in
Table 3.
TABLE-US-00003 TABLE 3 Embodiment according to the invention,
Comparative Example example Material Steel of material no. 1.4509
Titanium in accordance with EN 10 088-2 Thermal conductivity 25 22
(W/mK for 20.degree. C.) CTE (coefficient of thermal 10 8.8
expansion) of the connection element (10.sup.-6/.degree. C. for
0.degree. C.-100.degree. C.) Difference between CTE 1.7 0.5 of the
connection element and the substrate (10.sup.-6/.degree. C. for
0.degree. C.-100.degree. C.)
[0107] It was demonstrated that panes according to the invention
with glass substrates 1 and electrical connection elements 3
according to the invention have better stability against sudden
temperature differences. This result was unexpected and surprising
for the person skilled in the art.
LIST OF REFERENCE CHARACTERS
[0108] (1) Pane
[0109] (2) Electrically conductive structure
[0110] (3) Electrical connection element
[0111] (4) Solder material
[0112] (5) Wetting layer
[0113] (6) Compensation member
[0114] (7) Region of the electrical connection element 3
[0115] (8) Contact surface of the connection element 3 with the
electrically conductive structure 2
[0116] (9) Plug connector
[0117] (10) Indentation
[0118] (11) Spacer
[0119] (12) Contact bump
[0120] (17) Welding region
[0121] (18) Connection cable
[0122] (19) Connecting tab
[0123] (20) Notch
[0124] (20') Notch
[0125] (22) Subregion of 2
[0126] (23) Curve
[0127] b Maximum outflow width of the solder material
[0128] t Limiting thickness of the solder material
[0129] r Radius of curvature
[0130] A-A' Section line
[0131] B-B' Section line
[0132] C-C' Section line
[0133] D-D' Section line
[0134] E-E' Section line
* * * * *