Transparent pane with an electrical heating layer, method for its production and its use

Description [0001] The present invention belongs to the field of glazing technology and relates to a transparent glass pane with an electric heating layer, a method for its production as well as its use.

[0002] Transparent panes with an electric heating layer are known per se and have already been described many times in the patent literature. Just as an example, reference is made to the German disclosure documents DE 102008018147 Al and DE 102008020986 Al. In motor vehicles, they are often used as windshields, because the central field of view, due to legal requirements, cannot show any significant restrictions of vision. Thanks to the heat generated by the heating layer, condensation, moisture and ice can be removed quickly.

[0003] The heating current is usually introduced into the heating layer through at least one pair of strip or band electrodes. As collecting lines or collecting electrodes, they should introduce the heating current as evenly as possible into the heating layer and distribute it over a wide front. The electrical surface resistance of the heating layer is relatively high for materials currently used in industrial series production and in terms of order of magnitude can be several ohms per unit area. However, to obtain sufficient heating power for practical use, the supply voltage must be sufficiently high, for example, in motor vehicles, for example, only on-board voltage from 12 to 24 V is available as standard. Since the surface resistance of the heating layer increases with the length of the current paths of the heating current, the distance between the collector cables with the opposite polarity should be as small as possible. In vehicle shafts, which are usually wider than longer ones, the collection lines are placed along both long edges of the glass so that the heating current can flow along a shorter path of glass height. However, the consequence of this design is that the resting or parking position of the windscreen wipers intended for wiping the windscreen is usually located outside the heating zone so that sufficient heat output is no longer available and the windscreen wipers can freeze.

[0004] There have been many attempts to solve this serious problem.

[0005] For example, European patent application EP 0 524 527 A2 shows a windshield equipped with an electric heating layer, in which two flat heating strips are provided as heating elements in the wiper folding area. The heating strips are each electrically connected to one pole with the help of the bottom collecting cable located next to the bottom edge of the glass, as well as to the other pole of the voltage source using a conductive wire. The disadvantage of this system is that the bottom collecting cable is additionally loaded with current for both heating strips.

[0006] Furthermore, German Patent Application DE 102007008833 A1 and International Patent Application WO 2008/104728 A2 show an electrically heated windshield which can be further heated in the wiper folding area. For this purpose, heating wires are provided, which are connected to the lower collecting line as a grounding connection. The heating cables are loaded by the potential in the field of view regardless of the glass heating. Also in this arrangement, the lower collecting cable is additionally loaded by the current for the heating wires.

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[0007] European patent EP 1 454 509 BI and US patent 7,026,577 B2 propose a transparent glass in which the heated field of view is surrounded by two current busbars. The field of view is separated by one of the two current busbars, in particular by an area without a layer, from the additional heating area. Additional current busbars of opposite polarity are provided in the additional heating area to heat the glass in the masked area below the field of view.

[0008] International patent application WO 2011/141487 A1 proposes a transparent glass with a transparent heating coating which extends at least through a part of the glass surface, in particular through its field of view. The heating shell is divided by at least one heating shell-free zone into at least one first heating shell zone and one second heating shell zone, whereby both heating shell zones are electrically connected to at least two collective lines, so that after applying voltage power supply, which is supplied by a voltage source, each time the current flows through at least one first heating zone formed by the first zone of the heating coating and at least one second heating zone formed by the second zone of the heating coating. In the coating-free zone there is at least one heating element that has such electrical resistance that by applying a supply voltage to the heating element, the glass can be heated in the area of ​​the surface containing the zone free of the heating coating. The at least one heating element is formed in such a way that by applying supply voltage to the heating element, the pane can be heated in at least one area of ​​the surface adjacent to the zone free of the heating coating, which comprises at least one collection pipe.

[0009] Finally, international patent application WO 2012/110381 A1 proposes a transparent glass pane with an electric heating layer that extends at least through a part of the pane surface and can be electrically connected to the voltage source by means of connection means. The connection means comprise a first band-shaped collection line and a second band-shaped collection line, which are each electrically connected directly to the heating layer along the entire length of the band, so that when the supply voltage is applied, the heating current flows through the heating field formed by the heating layer. The first collection cable is electrically connected directly to the at least one first flat ribbon cable and the second collection cable to the at least one second flat ribbon cable. In addition, the glass has at least one glass zone that is free of the cooking zone, in which at least one electric heating element of the zone is located. The zone heating element has such electrical resistance that by applying the supply voltage, the glass zone free of the cooking zone can be heated, whereby the zone heating element in the electric parallel connection with the cooking zone is electrically connected directly to at least one first flat ribbon cable and at least a second flat ribbon cable.

[0010] While, in particular, some progress has been made thanks to the heated transparent glass of international patent applications WO 2011/141487 A1 and WO 2012/110381 A1, but the growing market demands call for further improvements to the previously known glass panes.

[0011] Thus, due to the geometry in the resting position or parking area of ​​the windscreen wipers, the windshield construction according to the international patent application WO 2011/141487 A1 can only be used on a few car models. In addition, the design in terms of variability of supply voltage and

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-3ΕΡ3 178 294 BI adaptation to various electrical resistances of the heating layer is not flexible enough to meet all requirements.

[0012] The heated transparent glass in international patent application WO 2012/110381 A1 has the disadvantage that an additional method step is required to apply heating wires to an adhesive film made for example of polyvinyl butyral (PVB). Due to this additional method step, the adhesive film must be processed prior to lamination, which results in a higher defect rate due to contamination and thus a higher rejection rate.

[0013] European patent EP 1 626 940 B1 is heated glass to prevent water condensation. The glass comprises, at least on one side, a resistance layer or heating layer that contains a plurality of indentations / recesses so that the glass obtains a predetermined desired electrical resistance. In this case, the resistance layer or heating layer is divided by indentations / recesses into several interconnected areas. In addition, the indentations / recesses may be of such nature that they each time form areas with different geometrical characteristics, which consequently have different resistances and thus different heating effects. Indentations / pits can be created using laser technology or by grinding. Glasses are mainly used in freezers, such as those usually used in bars, pastry shops or supermarkets. The disadvantage here is that the resistive layer or the heating layer must be placed between at least two busbars or collecting lines so that, apart from the resistive layer or the heating layer limited by the collecting pipes, no or only a small heating power is available. A European patent cannot tell whether this well-known heated glass is suitable or not for heating the resting position area or parking the windscreen wipers. Furthermore, it is added that Figure 3 of the European patent does not clearly show the course of the current paths, since the two opposing longer busbars are also separated by indentations / indentations in two electrically insulated areas.

[0014] From WO 2011/141487 A1, WO 03/051088 A2, US 5 877 473 A and EP 0 524 537 A2 further windscreens with electrically heated coatings and special means for heating the wiper field are known.

[0015] On the other hand, the object of the present invention is to improve in a preferred manner previously known heated transparent glass panes with an electric heating layer and to heat the resting position or parking area of ​​the windshield wipers (hereinafter referred to as the "wiper parking zone"). Improved, heated, transparent windows should have a heated wiper parking zone, which can be produced in a cheap way, and their design should be easy to adapt to various electrical resistances of the electric heating layer and different levels of supply voltage.

[0016] These and further objects are achieved after presenting the proposal of the invention by means of a heated, transparent glass having the features of an independent patent claim. Further preferred embodiments of the invention are indicated by the features of the dependent claims.

In a preferred embodiment of the pane according to the invention, the surface of the first pane on which the electrically heated coating is placed is connected flat to the second pane by means of a thermoplastic intermediate layer.

[0018] As first and / or second panes, all electrically insulating substrates which are thermally and chemically stable as well as dimensionally stable under the conditions of manufacture and use of the pane according to the invention are generally suitable.

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[0019] The first pane and / or second pane preferably comprise glass, particularly preferably flat glass, float glass, quartz glass, borosilicate glass, soda-lime glass or colorless plastics, preferably rigid colorless plastics, in particular polyethylene, polypropylene, polycarbonate, polymethyl methacrylate, polystyrene, polyamide, polyester, polyvinyl chloride and / or mixtures thereof. The first windshield and / or second windshield are preferably transparent, especially for the use of the windshield as the windshield or rear window of the vehicle or other applications where high light transmission is required. In the sense of the invention, transparent glass is then understood to have a transmission in the visible spectrum> 70%. For windows that are not in the driver's field of vision, such as roof windows, transmission may also be significantly lower, for example> 5%.

[0020] The thickness of the pane according to the invention can be very different and thus can be perfectly adapted to the requirements of a particular case. Preferably glass panes with standard thicknesses from 1.0 mm to 25 mm, preferably from 1.4 mm to 2.5 mm for automotive glass and preferably from 4 mm to 25 mm for furniture, devices and buildings, especially for electric heating bodies are used . The size of the glass can be very different and is adapted to the size of the application according to the invention. The first glass and possibly the second glass have areas from 200 cm² up to 20 m², usually for example in vehicle construction and architecture.

[0021] The glass according to the invention may have any three-dimensional shape. Preferably, the three-dimensional shape has no shadow zones so that it can be covered, for example, by cathodic sputtering. Preferably, the substrates are flat or slightly or strongly bent in one direction or in several directions of space. In particular, flat substrates are used. The glass can be colorless or colored.

[0022] Several panes are connected by at least one intermediate layer. The intermediate layer preferably comprises at least one thermoplastic plastic, preferably polyvinyl butyral (PVB), ethylene acetate acetate (EVA) and / or polyethylene terephthalate (PET). However, the thermoplastic intermediate layer may also contain polyurethane (PU), polypropylene (PP), polyacrylate, polyethylene (PE), polycarbonate (PC), polymethyl methacrylate, polyvinyl chloride, polyvinyl acetate resin, casting resins, fluorinated ethylene propylene copolymers, polyifluoride vinyl and / or ethylene tetrafluoroethylene copolymers and / or copolymers or mixtures thereof. The thermoplastic intermediate layer may be formed by one or more superimposed thermoplastic films, the thermoplastic film thickness being preferably from 0.25 mm to 1 mm, usually 0.38 mm or 0.76 mm.

[0023] In the case of a composite pane according to the invention consisting of a first pane, an intermediate layer and a second pane, the electrically heated coating can be applied directly to the first pane or applied to the carrier foil or the intermediate layer itself. The first pane and the second pane each have an inner surface and an outer surface. The inner surfaces of the first and second glass are facing each other and connected with each other by a thermoplastic intermediate layer. The outer surfaces of the first and second glass are facing away from each other and from the thermoplastic intermediate layer. An electrically conductive coating is applied to the inner surface of the first pane. Of course, another electrically conductive coating may also be applied to the inner surface of the second pane. The outer surfaces of the glass may also have coatings. The terms "first pane" and "second pane" are used to distinguish between the two panes in the case of a composite pane according to the invention. There are no findings about the geometrical system associated with the concepts. If, for example, the glass according to the invention to separate in an opening, for example a vehicle or building, an interior

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-5ΕΡ3 178 294 BI from the external environment, then the first glass can be turned to the interior or the external environment.

[0024] The transparent pane according to the invention comprises an electrically conductive, heated, transparent coating which extends at least over a significant part of the pane surface, in particular through its field of view. The electrically conductive coating is electrically connected to at least two, especially two collecting electrodes provided for electrical connection to the two poles of the voltage source, so that by applying a supply voltage the heating current flows through the heating field formed between the two collecting electrodes. Typically, both collecting electrodes are each formed in the form of a strip or band electrode, busbar or busbar for conduction and wide distribution of current in an electrically conductive coating. To this end, they are galvanically connected to the heating layer.

[0025] At least one, especially one of the two collecting electrodes, especially the upper collecting electrode in the transparent glass installation state, can be divided into at least two, especially two separated from each other partial areas.

[0026] In a preferred embodiment, the collecting electrode is formed as a printed and fired conductive structure. The printed collecting electrode preferably contains at least one metal, metal alloy, metal compound and / or carbon, particularly preferably a precious metal, especially silver. The printing paste for producing the collecting electrode preferably contains metal and / or carbon particles, in particular precious metal particles such as silver particles. Electrical conductivity is preferably achieved by electrically conductive particles. The particles may be in an organic and / or inorganic matrix, such as pastes or inks, preferably as a printing paste with glass frits.

[0027] The layer thickness of the printed collecting electrode is preferably from 5 pm to 40 pm, particularly preferably from 8 pm to 20 pm and even more preferably from 8 pm to 12 pm. Printed collecting electrodes with these thicknesses are technically easy to make and have favorable current carrying capacity.

[0028] Specific resistance p_and the collecting electrode is preferably from 0.8 pOm-cm to 7.0 pOm-cm, particularly preferably from 1.0 pOm-cm to 2.5 pOm-cm. Collecting electrodes with specific resistances in this area are technically easy to manufacture and have favorable current carrying capacity.

[0029] Alternatively, the collecting electrode may also be formed as a strip or, in the case of a collecting electrode divided into partial areas, as at least two, especially two strips of electrically conductive film. The collecting electrode then contains, for example, at least aluminum, copper, tinned copper, gold, silver, zinc, tungsten and / or tin or their alloys. The strip preferably has a thickness of from 10 pm to 500 pm, particularly preferably from 30 pm to 300 pm. Collecting electrodes made of electrically conductive films of this thickness are technically easy to make and have favorable current carrying capacity. The strip can be electrically connected to an electrically conductive structure, for example by soldering, by an electrically conductive adhesive or by direct application.

[0030] The electrically conductive pane coating according to the invention can be divided into a heating field, i.e. the heating part of the electrically conductive coating which is arranged between the two collecting electrodes so that a heating current can be introduced, and an area outside said heating field.

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[0031] Electrically heated coatings are known, for example, from documents DE 20 2008 017 611 Ul, EP 0 847 965 BI or WO 2012/052315 Al. They usually contain one or more functional layers, for example two, three or four electrically conductive functional layers. The functional layers preferably contain at least one metal, such as silver, gold, copper, nickel and / or chromium or metal alloy. The functional layers particularly preferably contain at least 90% by weight of metal, especially at least 99.9% by weight of metal. Functional layers may consist of metal or metal alloy. The functional layers particularly preferably contain silver or an alloy containing silver. Such functional layers have particularly favorable electrical conductivity with simultaneous high transmission in the visible light spectrum. The thickness of the functional layer is preferably from 5 nm to 50 nm, particularly preferably from 8 nm to 25 nm. In this functional layer thickness range, preferably a high transmission in the visible light spectrum and particularly favorable electrical conductivity are obtained.

[0032] Usually, at least one dielectric layer is disposed between two adjacent functional layers of the electrically conductive coating each time. Preferably, another dielectric layer is placed under the first and / or above the last functional layer. The dielectric layer comprises at least one single layer of dielectric material, for example nitride, such as silicon nitride, or oxide, such as alumina. However, the dielectric layer may also contain several individual layers, for example single layers of dielectric material, smoothing layers, matched layers, blocking layers and / or anti-reflective layers. The thickness of the dielectric layer is, for example, from 10 nm to 200 nm.

[0033] This layered structure is usually obtained as a result of a number of deposition processes that are carried out in a vacuum process such as magnetic field supported cathodic sputtering.

[0034] Other suitable electrically conductive coatings preferably contain tin and indium (ΓΓΟ) oxide, fluorine-doped tin oxide (SnCh: F) or aluminum-doped zinc oxide (ZnO: Al).

[0035] Basically, the electrically conductive coating can be any coating with which electrical contact should occur. If the glass according to the invention is to allow transparency, as is the case for example in the case of glass panes in the glass region, the electrically conductive coating is preferably transparent. The electrically conductive coating is transparent to electromagnetic radiation, particularly preferably to electromagnetic radiation with a wavelength of 300 to 1300 nm, and especially for visible light.

[0036] In a preferred embodiment, the electrically conductive coating is a layer or layer structure of several individual layers with an overall thickness less than or equal to 2 pm and especially less than or equal to 1 pm.

[0037] Preferably, the electrically conductive coating has a surface resistance of 0.4 Ω / π to 10 Ω / π. In a particularly preferred embodiment, the electrically conductive coating according to the invention has a surface resistance of 0.5 Ω / n to 1 Ω / π. Coatings with such surface resistances are particularly suitable for heating the windows of vehicles with a typical on-board voltage of 12 V to 48 V or for electric vehicles with a typical on-board voltage of up to 500 V.

[0038] The electrically conductive coating may extend across the entire surface of the first pane. An electrically conductive coating can alternatively also

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-7 ΕΡ3 178 294 BI pass only through part of the surface of the first glass. The electrically conductive coating preferably extends through at least 50%, particularly preferably through at least 70%, and even more preferably through at least 90% of the inner surface of the first pane.

[0039] In a preferred embodiment of the transparent pane according to the invention as an insulated pane, the inner surface of the first pane has a circumferentially extending edge area 2 mm to 50 mm wide, preferably 5 mm to 20 mm wide, which is not provided with an electrically conductive coating. The electrically conductive coating is then not in contact with the atmosphere and inside the glass is preferably protected against damage and corrosion by a thermoplastic intermediate layer.

[0040] In the transparent glass according to the invention, the cooking zone comprises at least one coating-free zone in which there is no electrically conductive coating. The coating-free zone is limited by the edge of the zone formed at least partly by the electrically conductive coating.

[0041] In particular, the coating-free zone has a circumferentially extending edge of the zone which is completely formed by an electrically conductive coating.

[0042] However, the edge of the zone may pass into the surrounding edge of the electrically conductive coating, such that the coating-free zone is directly connected to the peripherally-running edge of the glass, the coating-free edge strip of the transparent glass according to the invention.

[0043] The coating-free zone may have different contours. Thus, the contour can be square, rectangular, trapezoidal, triangular, pentagonal, hexagonal, heptagonal or octagonal with rounded corners and / or curved edges, as well as round, oval, drop-shaped or elliptical. The contour lines may have a straight, wavy, zig-zag and / or sawish shape. Several of these geometric features can be achieved in one and the same coating-free zone.

[0044] In particular, the coating-free zone serves as a communication window that is permeable to electromagnetic radiation, in particular infrared radiation, radar radiation and / or radio radiation. Sensors such as rain sensors can also be placed in the communication window.

[0045] A coating-free zone may be formed, for example, by masking in the event of a heating layer being applied to the substrate, or by removing the heating layer, for example, by mechanical and / or chemical removal and / or by removal by irradiation with electromagnetic radiation, especially laser radiation, after applying an electrically heated coating.

[0046] In a preferred embodiment, at least one coating-free zone is available. Preferably at least two, especially at least three coating-free zones are available.

[0047] Preferably, at least one coating-free zone or at least one communication window in the assembled state of the transparent pane is arranged in its upper area.

[0048] The collecting electrodes and / or their partial areas electrically contact one or more supply lines.

[0049] The power cord is preferably formed as a flexible foil cord or a flat cord or flat band cable. This should be understood as an electric wire whose width is much greater than its thickness. So flat

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The conductor is, for example, a strip or strand containing or consisting of copper, tinned copper, aluminum, silver, gold or their alloys. For example, a flat cable has a width of 2 mm to 16 mm and a thickness of 0.03 mm to 0.1 mm. The flat cable may have insulating, preferably polymeric insulation, e.g. based on polyimide. Flat cables that are suitable for contact with electrically conductive coatings in the panes, for example, have a total thickness of only 0.3 mm. Such thin flat cables can easily be embedded between individual panes in a thermoplastic intermediate layer. Several electrically insulated conductive layers may be arranged in the flat ribbon cable.

[0050] Alternatively, thin metal wires can also be used as an electric power cord. Metal wires in particular contain copper, tungsten, gold, silver or aluminum or alloys of at least two of these metals. The alloys may also contain molybdenum, rhenium, osmium, iridium, palladium or platinum.

In a preferred embodiment of the transparent pane according to the invention, each of at least two, especially two collecting electrodes is electrically connected to the poles of a voltage source by means of one flat cable in each case.

In a further preferred embodiment, at least two, especially two partial areas of at least one, especially one, collecting electrode are electrically connected in each case with one flat cable connected to the voltage source. Preferably, the flat conductors are located in the area of ​​the partial areas, which is located close to the other side of the glass edge assigned thereto. In this preferred embodiment, there is electrical insulation of the flat wires from the electric power wires by the spatial separation of the elements. In yet another preferred embodiment, at least two, especially two partial areas of at least one, especially one collecting electrode, are electrically connected to a flat cable. Preferably in this embodiment, the flat cable is positioned in the middle between the two opposite ends of the partial areas. This is preferably achieved by a common electrically conductive connecting part or by two electrically conductive connecting parts assigned to the respective partial area. The flat cable can be connected to the electrically conductive connecting part by means of a flat metal strip, in particular a copper strip.

[0053] The flat conductor and at least one connecting part and possibly a flat metal strip, in particular a copper strip, are electrically insulated from at least two electric supply lines.

[0054] In this case, the electrical insulation between the flat conductor and the connecting part on one side and the at least two electrical supply conductors on the other is achieved by means of an electrically insulating layer, in particular by means of an electrically insulating strip-shaped layer, between the flat conductor and the part connecting on one side and at least two electric power cords on the other. An electrically insulating layer, especially an electrically insulating strip-shaped layer, covers at least the intersection points of the connecting part with at least two electric power cords. It can, however, also be adjacent to two opposite end edges of the partial areas.

[0055] Preferably, the system has a whole sandwich structure consisting of the following layers arranged on top of each other:

glass, insulated sections of electric power cables,

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-9ΕΡ3 178 294 BI partial areas adjacent to the electric power cables outside the heating zone, to the edges of the zone which are adjacent the opposite edges of the electrically insulating layer; at the same time, these edges may be adjacent to opposite end edges of both partial areas of the collecting electrode, a flat conductor arranged on an electrically insulating layer, partial areas of the collecting electrode, as well as an electrically connected connecting part.

[0056] An important advantage of this system is that only one flat cable is needed to supply the two partial areas of the collecting electrode, which greatly simplifies the production of the transparent pane according to the invention.

[0057] In the case of the transparent glass according to the invention, it is important that in addition to the heating field and spatially separated from it longitudinally by at least one, especially one of the collecting electrodes described above, at least one, especially one first side of the edge of the glass, it has at least one more, especially one, heated, electrically conductive coating of the type described above. Preferably, this further heated, electrically conductive coating in the mounted condition of the windshield according to the invention is located below the lower collecting electrode and / or above the upper collecting electrode in the area of ​​the wiper parking zone.

[0058] In this further heated, electrically conductive coating, at least one additional electrode is located in the area of ​​both second sides of the edge of the glass each time. Preferably, the at least two additional electrodes are vertically oriented in the mounting position of the glass according to the invention. They are in each case connected by at least one, especially one power supply cable to the collecting electrode which has the opposite polarity to the nearest collecting electrode. It meant that when the upper collecting electrode is electrically connected to the positively charged pole of the voltage source, both additional electrodes located above the upper collecting electrode are electrically connected to the negatively charged lower collecting electrode via electric power cords. Conversely, if the additional electrodes are located in the bottom, next, heated, electrically conductive layer below, for example, a negatively charged bottom collecting electrode, they are electrically connected to the positively charged upper collecting electrode via electric power cords. An expert in the field can easily indicate further configurations based on this technical knowledge.

[0059] Preferably, the additional electrodes and electric power cords are much longer than wider. The length mainly depends on the size of the glass according to the invention. Preferably, the width is from 10 to 10 mm, especially from 10 to 1 mm. Preferably they have the same thickness as the collecting electrodes.

[0060] Particularly preferably, the electric power cables have a constant thickness and width over their entire length.

[0061] The electric power cables run along the respective associated edge of the coating and along both other sides of the pane edge at least partly in the associated edge strip, on the associated part of the circumferentially extending edge of the coating through at least one associated coating-free line, electrically disconnected from the heating field and /or,

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-10ΕΡ3 178 294 BI in and / or on each electrically conductive coating outside the cooking zone by at least one associated coating-free line, electrically disconnected from the cooking zone.

[0062] Preferably, the electric supply lines run on the electrically conductive coating in each case outside the cooking zone.

[0063] Preferably, the electric power cords are at least partially rectilinear, wavy, winding, sawtooth and / or zigzag. Preferably, the electric power cables run straight along their entire length.

[0064] The glass according to the invention has in at least one, in particular one, further heated, electrically conductive coating, at least one, in particular at least two, associated to a respective additional electrode, counter electrodes, electrically coupled to the associated additional electrode of opposite polarity. In the sense of the invention, the term "coupled" should be interpreted as "electrically connected through an electrically conductive coating.

[0065] Preferably, the opposing auxiliary electrodes and the opposing auxiliary electrode are arranged in a mirror image relative to the center line or the axis of the mirror pane according to the invention.

[0066] The pane according to the invention furthermore has at least one, in particular one heated, electrically conductive layer, at least two, especially two arranged mirror (in particular mirror relative to the vertical center line and mirror glass axis transparent) systems at least four, each preferably at least five coating-free lines which are arranged in such a way that they direct the heating current flowing from at least two additional electrodes during the application of the supply voltage through at least one, preferably at least two, each counter-electrode assigned to them, to at least one collecting electrode each time with the opposite polarity, where the coating-free lines determine the current paths_n and their length.

[0067] The additional electrode is connected directly to the busbar via an electric power cable. In contrast, the counter electrode is not directly connected to the second busbar with opposite polarity. The so-called "counter-electrode" is therefore not actually an electrode in the proper sense, but a connecting cable that connects two shell segments that are formed by coating-free lines so that current can flow between the shell segments.

[0068] Current flow of all current paths ai - a_n is generated by the potential difference between the additional electrode (connected to the first busbar) and the second busbar. The segmentation of the conductive coating formed by the coating-free lines, as well as the connection of the segments with the help of a counter-electrode (counter-electrodes) / connecting (connecting) wire (s) is used to control the flow of current in the form of current paths ai - a_n.

[0069] According to the invention, equation I applies to current paths a_n in a system free of lines:

VHi = hi: b_n = 0.5 to 2.0, preferably from 0.75 to 1.5, in particular from 0.8 to 1.2 (I), where VHi is the mathematical ratio (hi: b_n), n is an integer from 2 to 30, preferably from 2 to 25, especially from 3 to 20. h is the current path height ai, bn is the current path width a_n. The height h and current path ai is

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-11ΕΡ3 178 294 BI is an imaginary section that is oriented vertically to the direction of current flow between the two boundary lines free of coating.

[0070] ai is the current path from the additional electrode to the nearest opposite counter-electrode section (connecting wire). a2 to a_n mean successive current paths. Using ai - a_n you can specify the current paths themselves or also their length.

[0071] Width b_n current path a_n is an imaginary segment that is positioned vertically relative to the direction of current flow between two boundary lines free of coating.

[0072] Preferably the widths b_n are arranged in parallel or approximately parallel to each other, preferably at an imagined angle of ± 30 °, more preferably ± 20 °, in particular ± 10 °.

[0073] Length ratios of individual current paths ai to a_n they do not affect the correct heating power in these current path sections. Only the total length affects the correct heating power, i.e. the total resistance of the current paths (ai + a2 + as + .......

and_n) as well as the ratio of VHi to section width.

[0074] The coating-free lines run at least partially continuously and / or as broken lines of discrete cuts. Preferably they run continuously along their entire length, i.e. without cuts.

[0075] The length of the coating-free lines can be very different and can therefore be advantageously adapted to the requirements of a particular case. The width of coating-free lines is much smaller than their length and may change in its course. Preferably, the width is constant throughout the entire course. Preferably, the width is in the range of 10 to 1 mm.

[0076] With this system of at least four coating-free lines, at least two current paths a are determined_n in the respective lower and / or upper, and especially the lower, further heated electrically conductive coating. When applying the voltage supplying the heating current in this system, it flows from at least one additional electrode through at least one counter electrode (connecting cable) through current paths to the lower and / or upper collecting electrode (s).

[0077] A very particular advantage of the system according to the invention is that thanks to this the lower and / or the upper, subsequent (subsequent) heated (heated), electrically conductive (conductive) coating (s) are (are) evenly heated (heated) , with a proper heating power of 300 to 900 W / m²and preferably from 350 to 800 W / m².

[0078] Another special advantage of the configuration of the additional electrodes, counter electrodes (connecting wires) and coating-free line systems is that the entire configuration can be easily adapted to the requirements of the specific case by simple parallel movements, for example additional electrodes and / or counter electrodes (connecting cables), without damaging the proper heating power, for example by hot spots and / or cold spots. The optimal configuration for a particular case can be easily determined using popular and well-known simulation programs.

[0079] In general, the pane configuration of the invention, even at particularly low temperatures <0 ° C, especially <-10 ° C, very effectively prevents freezing of the wipers in the wiper parking zone.

[0080] In a preferred embodiment of the transparent pane according to the invention, the areas in which the collecting electrodes are arranged, the flat cable (flat cables), the electrode

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Auxiliary or additional electrodes, electrical power cords, as well as a coating-free line system, are partially or fully optically masked by common and known opaque, opaque or opaque masking strips. The masking strip covers these and other functional elements in these areas, and also protects them from UV radiation, which can damage functional elements. Namely, the black masking strip includes an optically opaque, opaque partial area, which on its edge becomes an optically partially transparent partial area. The optically partially transparent partial area is, for example, a dot grid. Preferably, the masking strip is applied and fired on the inner side, i.e. the side of the outer pane facing the inner pane, by screen printing, before joining both panes with a layer of adhesive.

[0081] Preferably, the pre-products of the masking strips are applied by screen printing to the uncovered glass panes, after which the applied layers are baked.

[0082] The panes according to the invention may be manufactured in the usual and known manner. Preferably they are produced using the method of the invention.

[0083] The method of the invention comprises the following method steps:

(A) producing an electrically conductive coating;

(B) producing at least one coating-free communication window in the electrically conductive heating zone coating;

(C) the creation (cl) of at least two voltage source connected to both poles collecting electrodes that are electrically connected to the electrically conductive coating so that by applying the supply voltage the heating current flows through the heating field between the two collecting electrodes and / or ( c2) at least two voltage electrodes connected to both poles, which are electrically connected to an electrically conductive coating, wherein at least one of the two collecting electrodes is divided in at least two spatially separated partial areas;

(D) producing (dl) at least two additional electrodes opposed in a mirror image of the center line (and mirror axis) of the transparent pane;

(d2) at least two opposing in a mirror image of the transparent glass center line (and mirror axis) and electrically assigned additional counter electrodes (connecting wires), which are electrically coupled when the supply voltage is applied (i.e. electrically connected by an electrically conductive coating) with a collecting electrode of opposite polarity;

(d3) at least two transparent glass connecting to the center line (and mirror axis), placed in a mirror image, at least one additional electrode each, with at least one collecting electrode or each with at least one of its partial electric parts power cords, which run along the respective assigned edge of the coating and along both other sides of the edge of the pane at least partially in the associated edge strip,

57P45647PL00

-13ΕΡ3 178 294 BI on the assigned part of the peripherally running edge of the coating by at least one assigned free coating line, electrically disconnected from the cooking zone and / or in each associated electrical coating outside the heating field by at least one assigned free coating line, electrically disconnected;

(E) the creation of (el) at least two shell-free lines that run along the electric power lines on the heating field side, and (e2) at least two opposite systems in the mirror image of each at least four shell-free lines that are placed so that when applying the supply voltage they direct the heating current flowing from at least two additional electrodes through at least two current paths a_n and by at least two counter-electrodes (connecting cables) assigned to them at least to each collecting electrode of opposite polarity each time, whereby for current paths a_n in the system of coating-free lines equation I applies:

VHi = hi: b_n = 0.5 to 2.0, preferably from 0.75 to 1.5, especially from 0.8 to 1.2 (I), where n is an integer from 2 to 30, preferably from 2 to 25, and especially from 3 to 20, (ai) means the current path from the additional electrode to the nearest opposite counter-electrode section (connecting cable), (hi) means the height of the current path ai, (a2 ... a_n) means successive current paths, b_n is the width of the next current path a_n and (VHi) means the mathematical ratio (hi: b_n), (F) wherein the steps (B) and (E) of the method are carried out sequentially or simultaneously and (G) the steps (C) and (D) of the method are carried out simultaneously or sequentially, as well as before or after steps (B) and (E) way.

[0084] Ratios of lengths of individual current paths ai to a_n they do not affect the correct heating power in these current path sections. Only the total length affects the correct heating power, i.e. the total resistance of the current paths (ai + a2 + as + .......

and_n) as well as the ratio of VHi to section width.

[0085] In a further preferred embodiment of the method according to the invention, at least four coating-free lines as well as at least two systems are produced by laser ablation of an electrically conductive coating inside and outside the heating field.

[0086] In a further preferred embodiment, the steps (C) and (D) of the method are performed by screen printing.

[0087] Namely, the application of the electrically conductive coating can occur in process step (A) by methods known per se, preferably by magnetic field-assisted sputtering. This is particularly advantageous due to the simple, fast, inexpensive and even coating of the first pane if the pane according to the invention

57P45647PL00

-14ΕΡ3 178 294 BI is formed as a double glazed unit. The electrically conductive, heated coating can also be applied by evaporation, chemical vapor deposition.

CVD - chemical vapor deposition), plasma assisted vapor deposition (PECVD) or by wet chemical processes.

[0088] The first glass after method step (A) may be heat treated. In this case, the first window with the electrically conductive coating is heated to a temperature of at least 200 ° C, preferably at least 300 ° C. Thermal treatment can be used to increase transmission and / or reduce the surface resistance of the electrically conductive coating.

[0089] The first pane can be bent according to process step (A), usually at a temperature of 500 ° C to 700 ° C. Since it is technically easier to cover a flat glass, this procedure is beneficial if the first glass is to be bent. Alternatively, the first glass may also be bent before process step (A), for example, if the electrically conductive coating is not able to survive the bending method without damage.

[0090] The application of the collecting electrodes in the process step (C) and the electric supply wires in the process step (E) are preferably by printing and baking an electrically conductive paste in a screen printing or ink-jet printing process. Alternatively, collecting electrodes and electric power cords may preferably be applied, soldered or glued as strips of electrically conductive film onto the electrically conductive coating.

[0091] In the screen printing process, lateral forming occurs by masking the fabric through which the printing paste is pressed with metal particles. For example, the width of the collecting electrode can be easily determined and changed with the help of a suitable masking construction.

[0092] Coating-free zones are produced in process step (B), preferably by mechanically removing the heated coating produced in process step (A). Mechanical removal can also be replaced or supplemented with treatment using appropriate chemicals and / or irradiation with electromagnetic radiation.

[0093] A preferred improvement of the method of the invention comprises at least the following successive steps:

placing the thermoplastic intermediate layer on the coated surface of the first pane and placing the second pane on the thermoplastic intermediate layer and connecting the first pane and the second pane with the thermoplastic interlayer.

[0094] In these method steps, the first pane is arranged so that those surfaces thereof, which are provided with a heated coating, face the thermoplastic intermediate layer. Thanks to this, the surface becomes the inner surface of the first glass.

[0095] The thermoplastic intermediate layer may be formed by a single film or also by two or several thermoplastic films that are arranged one above the other.

[0096] The joining of the first and second panes preferably takes place under the influence of heat, vacuum and / or pressure. Known as such processes can be used to make the glass.

[0097] For example, so-called autoclave processes may be carried out at elevated pressure from about 10 bar to 15 bar and temperatures from 130 ° C to 145 ° C for about 2 hours. Known as such, vacuum bag or vacuum ring processes operate for example at about 200 mbar and 80 ° C to 110 ° C. First glass

57P45647PL00

-15ΕΡ3 178 294 BI the thermoplastic intermediate layer and the second glass may also be pressed against the calender glass between at least one pair of rollers. Such devices are known for the production of glass and usually have at least one heating tunnel in front of the pressing plant. The temperature during the pressing process is, for example, from 40 ° C to 150 ° C. The combinations of calendering and autoclave processes proved to be particularly effective in practice. Alternatively, vacuum laminators can be used. They consist of one or more heated and emptying chambers, in which the first and second glass are laminated for example in about 60 minutes at a reduced pressure from 0.01 mbar to 800 mbar and temperatures from 80 ° C to 170 ° C.

[0098] The transparent glass according to the invention, in particular the transparent glass according to the invention produced according to the method according to the invention, can be perfectly used as a functional and / or decorative single element and / or as an integral part of furniture, devices and buildings, as well as in means of transport for moving on land, in the air or on water, especially on motor vehicles, for example as a windshield, rear window, side window and / or roof window. Preferably the transparent windshield according to the invention is formed as a vehicle windshield or vehicle side windshield.

[0099] It is obvious that the features listed above and explained below can be used not only in the indicated combinations and configurations, but also in other combinations and configurations or in a unique position, without departing from the scope of the present invention.

Brief description of the figures [0100] The invention is now explained in more detail on the basis of exemplary embodiments, with reference being made to the attached figures. Presented in a simplified, incompatible with the scale scheme:

Figure 1 a top view of the windshield 1 according to the invention in a simplified diagram;

Figure 2 a vertical cross-section through a section of a windshield according to the invention according to Figure 1;

Figure 3 a perspective schematic diagram of a windshield section according to the invention according to Figure 1;

Figure 4 a top view of a detailed section B of the windshield 1 according to the invention according to Figure 1;

Figure 5 a top view of a detailed section A of an exemplary embodiment of a windshield 1 according to the invention according to Figure 1;

Figure 6 a top view of a detailed section A of a further exemplary embodiment of a windshield 1 according to the invention according to Figure 1 together with an enlarged section C;

Figure 7 a top view of a detailed section A of a still further exemplary embodiment of a windshield 1 according to the invention according to Figure 1 together with an enlarged section D;

Figure 8 a top view of a detailed section of yet another exemplary embodiment of a windshield 1 according to the invention.

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-16ΕΡ3 178 294 BI

Detailed description of the Figures

Figure 1 in combination with Figure 2, 3 and 4 [0101] Figure 1 is a simplified diagram of the transparent windshield 1 of a motor vehicle seen from the inside. The windshield here is for example made of a composite glass pane whose construction is illustrated on the basis of a vertical cross-section through the windshield section 1 of Figure 2 and on the basis of a perspective schematic diagram of the windshield section 1 of Figure 3.

[0102] Accordingly, the windshield 1 has two rigid individual panes, namely the outer pane 2 and the inner pane 3, which are bonded together by a layer of thermoplastic glue 4, here e.g. polyvinyl butyral (PVB) film, copolymer film ethylene and acetate (EVA) or polyurethane film (PU). Both individual panes 2, 3 have approximately the same size and shape and may have, for example, a trapezoidal curved contour, which is not detailed in the Figures. They are, for example, made of glass, but can also be made of a material other than glass, such as plastic. In the case of applications other than windscreens, it would also be possible to manufacture both single panes 2, 3 from one flexible material. The contour of the windshield 1 is formed by the edge 5 common to both individual panes 2, 3, whereby the windshield 1 has at the top and bottom two opposite sides 6, 6 'as well as on the left and on the right two opposite sides pages 7.7 'each.

[0103] As shown in Figures 2 and 3, a transparent, electrically conductive coating 8 is separated on the side of the inner pane 3 connected by the adhesive layer 4. The heated, electrically conductive coating 8 is here, for example, essentially applied completely to the inner pane 3, the peripheral edge strip 9 extending on all sides is not coated such that the edge 10 of the electrically conductive coating 8 is retracted inwards relative to the edge 5 of the pane. Due to this, the electrical insulation of the electrically conductive coating 8 works outside. In addition, the electrically conductive coating 8 is protected against corrosion penetrating from the edge 5 of the pane.

[0104] The electrically conductive coating 8 contains in a known manner a sequence of layers with at least one electrically heated, metallic partial layer, preferably silver, and optionally further partial layers, such as anti-reflective and blocking layers. Preferably, the layer sequence has a high thermal load capacity, such that it is able to withstand the temperatures typically above 600 ° C required to bend glass panes without damaging them, and a layer sequence with low thermal load capacity can also be provided. The electrically conductive coating 8 can equally well be applied as a single metallic layer. It is likewise possible to apply an electrically conductive coating 8 indirectly to the inner pane 3, but to apply it first to a carrier, such as a plastic film, which is then glued to the outer and inner pane 2, 3. Alternatively, the carrier foil can be combined with the foil adhesive (e.g. PVB film) and as a three-layer system (trilayer) glued to the inner and outer pane 2, 3. The heated, electrically conductive coating 8 is preferably applied by ion sputtering or magnetron cathode sputtering onto the inner or outer pane 2, 3.

[0105] As shown in Figure 1, the electrically conductive coating 8 adhering to the first sides 6, 6 ', i.e. on the upper and lower edges 5 of the pane, is electrically connected to the upper band-shaped collecting electrode or busbar 11 and the lower collecting electrode 11 'band-shaped. The upper collecting electrode 11 and the lower collecting electrode 11 'are intended to be connected to one pole of a source not shown in each case

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-17ΕΡ3 178 294 BI voltage. Both collecting electrodes 11, 11 'with opposite polarity are used to evenly supply and distribute the heating current to the heating zone 12 between them heated coating 8. Both collecting electrodes 11, 11' are e.g. printed on electrically conductive coating 8 and each having least roughly straight course.

[0106] Collecting electrodes 11, 11 'can, however, also be divided in each case into two spatially separated partial areas.

[0107] When the windshield 1 is mounted, the upper collecting electrode 11 separates the heating field 12 from the partial area 8 'of the electrically conductive coating 8 running along the upper first side 6 of the edge 5 of the glass.

[0108] When the windshield 1 is mounted, the lower collecting electrode 11 'separates the hotplate 12 from the partial area 8' running along the lower first side 6 '. This partial area 8 'is used to heat the wiper parking zone. Further details regarding the various embodiments of the invention can be found in sections A in Figure 5 to 9.

[0109] Below the upper collecting electrode 11, in the center of the hotplate 12 in the mirror image, 3 coating-free communication windows are arranged. Ie. they are halved by the imaginary vertical center line M or the mirror axis.

[0110] From both ends of the upper collecting electrode II in the partial regions 8 of the coating 8 along the respective assigned partial region of the coating edge 10 run two mirrored electric cables 15, 15 'in relation to each other, to the opposite additional electrodes 18, 18' in the partial area 8 '. The electric power cables 15, 15 'and additional electrodes 18, 18' are made of the same material as the collecting electrodes 11, 1Γ.

[0111] The 15.15 'power supply cables and 18.18' additional electrodes are electrically disconnected from the hotzone 12 by each associated with them, running along the 15.5 'electric supply wires on the hotzone side, lines 16, 16' free of coatings. Lines 16, 16 'free of coating have a width of 100 pm. Preferably they can be produced by laser ablation.

[0112] The coating-free lines 16, 16 'extend to the upper collecting electrode 11 and further above the upper collecting electrode 11 up to the circumferentially extending edge strip 9 and separating the partial areas 8 running along the second sides 7, 7 from the partial area 8' running along upper first page 6. Further details can be found in slice B of Figure 4.

[0113] Figure 4 shows the intersection of 17 coating-free lines 16 with the upper collecting electrode 11. Preferably, this intersection 17 can be formed by the upper collecting electrode being pressed by screen printing 11 on the coating-free 16, prefabricated by laser ablation method .

[0114] Figure 4 also shows a preferred configuration of the black masking strip 13 because it is also used in the area of ​​the bottom collecting electrode 11 'and in areas 8, 15, 16. The masking strip 13 covers the functional elements in these areas and also protects them from radiation UV, which can damage functional elements. Namely, the black masking strip 13 comprises an optically opaque, opaque partial area 13 'that converts at its edge 13 into an optically partially transparent partial area 13' that itself extends to the edge 13. The optically partially transparent partial area 13 'is, for example, a dot grid. Preferably, the masking strip 13 is applied by screen printing to the inside, i.e.

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-18ΕΡ3 178 294 BI from the side of the outer pane 2 facing the inner pane 3, and fired before joining, before both panes 2 and 3 are joined by a layer of glue 4.

Figure 5 in combination with Figure 1 [0115] Figure 5 is a top view of the detail section A of the exemplary embodiment of the windshield 1 according to Figure 1.

[0116] Section A only shows the left partial area of ​​the coating 8 'in the area of ​​the wiper parking zone up to the centerline and the mirror axis M. The right partial area of ​​the coating 8' is a mirror image of the left partial area 8 'and is therefore not shown.

[0117] In this exemplary embodiment of Figure 5, the coating-free line 16 changes to a system 16 consisting of three horizontal coating-free lines and a vertical coating-free line with a line width of 30 pm. In this system 16, in the left partial area 8 ', three horizontal branches, parallel to each other, free of coating branch off at three branches 17. The upper coating-free line contacts the upper ends 20 of the vertically positioned additional electrode 18 and the vertically positioned leg of the counter electrode / connecting cable 19. The central free line of the coating contacts the lower end 20 of the additional electrode and ends at its end point 21 on the vertically arranged counter electrode / connecting cable leg 19. The lower coating-free line runs from its branching point 17 parallel to the lower circumferential edge 10 of the coating along the lower first side 6 'to the imaginary centerline M and beyond.

[0118] The upper coating-free line runs vertically downstream from the upper end 20 of the vertical leg of the counter electrode / connecting wire 19 and intersects the horizontal leg of the counter-electrode / connecting wire 19 at the intersection 17 'and then runs below the horizontal leg to point 17 of the branching of the lower free line shell.

[0119] Details of end points 20 can be found in enlarged slice C in Figure 6. Details of branching points 17 can be found in enlarged slice D in Figure 7.

[0120] Through this system 16 of four coating-free lines, two current paths ai and a2 are formed in the partial region 8 '. Current path ai extends from the additional electrode 18 to the vertical leg of the counter electrode / connecting cable 19; in this embodiment and the embodiments described below, this is the first current path. From the horizontal leg of the counter electrode / connecting cable 19, the current path a2 runs to the bottom collecting electrode 1Γ. The ratio is VHi = 0.9 and n = 2. When a 12 V supply voltage is applied, in the system 16 the heating current flows from the additional electrode 18 through the counter electrode / connecting cable 19 to the lower collecting electrode 1Γ.

[0121] A particular advantage of this system 16, 18, 19 according to the invention is that thanks to this the coating 8 'is evenly heated, with a proper heating power of 400 to 550 W / m². Another particular advantage of the system 16, 18, 19 according to the invention is that the entire configuration can be adapted to the requirements of the specific case by simple parallel displacements P, e.g. an additional electrode 18 and / or vertical leg of the counter electrode / connecting cable 19, without adversely changing proper heating power - for example, by hot spots and / or cold spots. Optimal configuration of 18, 19 electrodes and current paths ai ... a for a particular case_n can be easily determined using standard and known simulation programs.

57P45647PL00

[0122] In general, an embodiment of the transparent pane 1 according to the invention according to

Figure 5, effectively prevents wipers from freezing in the wiper parking zone, even at particularly low temperatures <0 ° C.

Figure 6 in combination with Figure 1 [0123] Figure 6 is a top view of the detail section A of the exemplary embodiment of the windshield 1 according to Figure 1.

[0124] As in Figure 5, slice A only shows the left partial area of ​​the coating 8 'in the area of ​​the wiper parking zone to the central axis and the mirror axis M. The right partial area of ​​the coating 8' is also a mirror image of the left partial area 8 'and therefore not requires presentation.

[0125] In this exemplary embodiment of Figure 6, the coating-free line 16 changes to a system 16 consisting of a total of three horizontal and two vertical lines free of coating having a line width of 30 pm. In this system 16, in the left partial area 8 ', three horizontal branches, parallel to each other, free from coating branch off at three branches 17. The upper coating-free line contacts the upper end of the additional electrode 18. The detailed information is included in the enlarged section C in Figure 6. Then the coating-free line runs along the horizontal bipartite counter-electrode / connecting wire 19. In this area the vertical coating line (branching point 17) branches which runs to the lower horizontal free line shell. The central horizontal coating-free line 16 contacts the lower ends of the vertical auxiliary electrode 18 and the vertical leg of the bipartite counter electrode / connecting wire 19 and extends to branching point 17 with the coating-free line positioned along the vertical leg of the counter electrode / connecting wire 19. Details 17 branching points can be found in the slice D in Figure 7.

[0126] In the area of ​​the end of the horizontal bipartite counter-electrode / connecting cable 19, the coating-free line runs vertically downwards and intersects spatially separated from it, but electrically coupled to the horizontal leg, the partial area of ​​the counter-electrode / connecting cable 19. The intersection point 17 'has same configuration as the intersection point 17 of Figure 4. The partial area of ​​the counter electrode / connecting cable 19 is then electrically coupled to the lower collecting electrode 1Γ, namely electrically connected via an electrically conductive coating.

[0127] Through this system 16 of five coating-free lines, three current paths ai, a2 and as are created. Current path ai runs from the additional electrode 18 to the vertical split leg of the counter electrode / connecting cable 19. From the horizontal lower leg of the counter electrode / connecting cable 19 runs the current path a2 to a separate horizontal partial area of ​​the counter electrode / connecting cable 19. The current path ace extends from this separate horizontal partial area 19 to the lower collecting electrode 1Γ.

[0128] The additional electrode 18 is connected directly to the first busbar 11 via an electric power cord 15. In contrast, the counter electrode 19 is not directly connected to the second busbar 1Γ. The counter electrode 19 is a connecting conductor that connects two shell segments to each other, which are formed by coating-free lines so that current can flow between the shell segments.

[0129] Current flow of all current paths ai - a_n is generated by the potential difference between the additional electrode 18 (connected to the first busbar 11) and the second electric busbar 1Γ. Segmentation of the conductive coating formed by

57P45647PL00

-20ΕΡ3 178 294 BI coating-free lines, as well as the connection of segments by means of counter-electrodes (counter-electrodes) 19 is used to control the current flow in the form of current paths ai - a_n.

[0130] The ratio is VHi = 1, VH2 = 1 and n = 2 and 3. When a 12 V supply voltage is applied, in the system 16 the heating current flows from the additional electrode 18 through the counter electrode / connecting cable 19 to the lower collecting electrode 1Γ. When a 12 V supply voltage is applied, in the system 16 the heating current flows from the additional electrode 18 through a two-split counter electrode / connecting cable 19 to the lower collecting electrode 1Γ.

[0131] A particular advantage of this system 16, 18, 19 according to the invention is that due to this the coating 8 'is evenly heated, with a proper heating power of 400 to 550 W / m². Another particular advantage of the system 16, 18, 19 according to the invention is that the entire configuration can be adapted to the requirements of the specific case by simple parallel displacements P, e.g. an additional electrode 18 and / or vertical leg of the counter electrode / connecting cable 19, without adversely changing proper heating power - for example, by hot spots and / or cold spots. Optimal configuration of 18, 19 electrodes and current paths ai ... a for a particular case_n can be easily determined using standard and known simulation programs.

[0132] In general, the embodiment of the transparent pane 1 according to the invention according to Figure 6 effectively prevents the wipers from freezing in the wiper parking zone, even at particularly low temperatures <0 ° C.

Figure 7 in combination with Figure 1 [0133] Figure 7 is a top view of the detail section A of the exemplary embodiment of the windshield 1 according to Figure 1.

[0134] As in Figures 5 and 6, slice A only shows the left partial area of ​​the coating 8 'in the area of ​​the wiper parking zone to the center line and mirror axis M. The right partial area of ​​the coating 8' is also here a mirror reflection of the left partial area 8 ' , therefore it does not require submission.

[0135] In this exemplary embodiment of Figure 7, the coating-free line 16 changes to a system 16 consisting of three horizontal and three vertical lines free of coating having a line width of 30 pm. In this system 16, in the left partial area 8 ', three horizontal branches, parallel to each other, free from coating branch off at three branches 17. From them, the upper coating-free line contacts the upper end of the vertical additional electrode 18 and the upper end of the vertical leg of the triple secondary electrode 19. Then the upper line free of the coating runs along the spatially separated upper partial area of ​​the triple counter-electrode / connecting cable 19. The upper partial area is electrically coupled to the lower, horizontal leg of the tripartite counter electrode and its third spatially separated, lower partial area.

[0136] Behind the end point 20 is the branch 17, in which the coating-free line branches vertically downwards and runs along the vertical leg of the two tripartite counter electrodes / connecting wires 19 (for details, see enlarged section D in Figure 7), crosses with the lower horizontal leg and ends on the lower horizontal shell-free line. In the further course, the upper, horizontal line free of the coating branches again, the branching free line extends vertically downwards, contacts the end point of the horizontal lower leg, then runs through the gap between the end of the horizontal lower leg and the third horizontal

57P45647PL00

-21ΕΡ3 178 294 BI with a partial area of ​​the triple counter-electrode / connecting cable 19, and then contacts the lower horizontal line free from the coating.

[0137] The upper coating-free line runs along the upper horizontal partial counter-electrode area / connecting cable 19, and then bends vertically downwards, touches the end of the upper horizontal partial area, intersects at a distance of 17 'horizontal, lower, third partial area of ​​the tripartite counter-electrode / connecting cable 19, and then also contacts the bottom horizontal line free from coating.

[0138] The horizontal, lower, third partial area of ​​the three-part counter-electrode / connecting cable 19 then extends further to the center line and the mirror axis M.

[0139] Through this system 16 six coating-free lines, 4 current paths ai, a2, as and a4 are created. Current path ai extends from the additional electrode 18 to the vertical tripartite leg of counter-electrode / connecting cable 19. From current horizontal leg of counter-electrode 19 runs current path a2 to a separate horizontal upper area of ​​the partial counter-electrode / connecting cable 19. The current path as runs from this separate horizontal upper partial area 19 to the horizontal lower partial area of ​​the three-part counter-electrode / connecting cable 19. From there, current path a4 runs to the lower collecting electrode 1Γ.

[0140] The ratio is VHi = 1.5 in = 2 to 4. When applying a 12 V supply voltage in the system 16, current flows from the additional electrode 18 through the triple counter-electrode 19 to the lower collecting electrode 1Γ.

[0141] A particular advantage of this system 16, 18, 19 according to the invention is that thanks to this the coating 8 'is evenly heated, with a proper heating power of 400 to 550 W / m². Another particular advantage of the system 16, 18, 19 according to the invention is that the entire configuration can be adapted to the requirements of the specific case by simple parallel displacements P, e.g. an additional electrode 18 and / or vertical leg of the counter electrode / connecting cable 19, without adversely changing proper heating power - for example, by hot spots and / or cold spots. Optimal configuration of 18, 19 electrodes and current paths ai ... a for a particular case_n can be easily determined using standard and known simulation programs.

[0142] In general, the embodiment of the transparent pane 1 according to the invention according to Figure 7 effectively prevents the wipers from freezing in the wiper parking zone, even at particularly low temperatures <0 ° C.

Figure 8 in combination with Figure 1 [0143] Figure 8 is a top view of the detail section A of the exemplary embodiment of the windshield 1 according to Figure 1.

[0144] As in Figure 5, 6 and 7, slice A only shows the left coating area 8 'in the area of ​​the wiper parking zone to the center line and mirror axis M. The right partial coating area 8' is a mirror image of the left partial area 8 'and therefore it does not have to be presented.

[0145] The form of the windshield 1 according to Figure 8 is an improvement of the form of the windshield 1 according to Figure 6. The difference is that in the form according to Figure 8, the coating 8 'in the area of ​​the wiper parking zone is divided into ten current paths ai-aio by two horizontal and ten vertical lines free from the coating, not on three current paths ai - as through three horizontal and three vertical lines free from the coating.

57P45647PL00

-22-3 178 294 BI [0146] The ratio is VHi = 1.5 in = 2 to 5. When applying the supply voltage

In system 16, current flows from the auxiliary electrode 18 through a four-fold counter-electrode / connecting cable 19 to the bottom collecting electrode 1Γ.

[0147] A particular advantage of this system 16, 18, 19 according to the invention is also that due to this the coating is heated particularly evenly 8 ', with a proper heating power of 500 to 700 to 0 W / m². Another particular advantage of the system 16, 18, 19 according to the invention is that the entire configuration can be adapted to the requirements of the specific case by simple parallel displacements P, e.g. an additional electrode 18 and / or vertical leg of the counter electrode / connecting cable 19, without adversely changing proper heating power - for example, by hot spots and / or cold spots. Optimal configuration of 18, 19 electrodes and current paths ai ... a for a particular case_n can be easily determined using standard and known simulation programs.

[0148] In general, the embodiment of the transparent windshield 1 according to the invention according to Figure 7 prevents particularly especially the freezing of the wipers in the wiper parking zone, even at particularly low temperatures <0 ° C.

[0149] In Figures 1 to 8, the references have the following meanings:

windshield outer pane inner pane adhesive layer circumferentially pane edge top first side of edge 5 pane when windshield is mounted 1

6 'lower first side of windshield edge 5 when windshield is fitted 1

7, 7 'side other side of the windshield edge 5 in the windshield mounted condition 1 electrically conductive coating

8 'lower electrically conductive coating 8 in the area of ​​the wiper parking zone, placed in the windshield mounting position 1 outside the heating zone 12 along the lower first side 6' edge 5 glass parts partial areas of the electrically conductive coating 8, located in the windscreen mounting state 1 outside the heating zone 12 along the second side 7 and 7 'of the edge 5 of the pane

8 'partial area of ​​the electrically conductive coating, located in the windshield mounted state 1 outside the heating zone 12 along the upper first side 6 edges 5 glass peripherally running edge strip, free of electrically conductive coating 8 circumferentially running edge of the coating upper collecting electrode in the windshield mounted state 1

1Γ lower collecting electrode when windshield is mounted 1 hotplate masking strip

13 'optically opaque, opaque partial area of ​​the masking strip 13

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-23ΕΡ3 178 294 BI edge of the optically opaque, opaque area of ​​the partial masking strip 13

13 'optically partially transparent part of the masking strip 13 edge of optically partially transparent part of the masking strip 13 communication window free from electrically conductive coating 8

15, 15 'electrical supply wires from the upper collecting electrode 11 along the respective assigned edge 10 of the coating in the respective assigned areas 8 partial to the additional electrodes 18, 18'

16, 16 'shell-free line running along the power cables

15, 15 'on the heating zone side 12 system of at least four lines free of coating 8' in the coating in the wiper parking zone.

intersection of lines 16, 16 free from the coating with the collecting electrode 11

17 'intersection of coating-free line 16 with counter-electrode 19 branching point of coating-free line 16

18, 18 'additional electrodes, electrically connected to the collecting electrode 11 by means of electric supply cables 15, 15', located in the lower electrically conductive coating 7 '(wiper parking zone) by counter electrode relative to the additional electrode 18 (connecting cable) end point of the additional electrode 18 or counter electrode 19 on the coating line 16 free of the coating ai length of the current path from the additional electrode 18 to the nearest opposite section of the counter electrode 19 a2 ... a_n current path length h and current path height ai b2 ... b_n current path width a2 to a_n l / 2 half half width

A enlarged section of the windshield 1

B enlarged section of the windshield 1

C enlarged section of the windshield 1

D enlarged section of the windshield 1

M vertical center line and mirror axis

P parallel shift

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-24ΕΡ3 178 294 BI