Transparent pane having an electrical heating layer, method for the production thereof, and use thereof

The invention relates to the field of panel technology and relates to a transparent panel with an electric heating layer, a method for its manufacture, as well as its application.

Transparent panels with an electric heating layer are known per se and have already been described many times in the patent literature. Only as an example, you can refer to the German laid out applications DE 102008018147 A1 and DE 102008029986 A1. In cars, they are often used as windscreens, since the central field of view, due to legal norms, should not have any significant visibility restrictions. Due to the heat generated by the heating layer, condensed moisture, ice and snow can be removed in a short time.

The heating current is introduced into the heating layer, typically with at least one pair of strip or tape electrodes. They must, as busbars or collector electrodes, introduce the heating current as evenly as possible into the heating layer and distribute them over a wide front. The electrical surface resistance of the heating layer is relatively high in materials currently used in industrial mass production, and can be on the order of several ohms per unit area. However, in order to achieve a heating power sufficient for practical use, the supply voltage must be correspondingly high, but, for example, only on-board voltage from 12 to 24 V is provided in cars in a standard way. Since the surface resistance of the heating layer increases with the length of the conductive paths of the heating current, busbars of opposite polarity should have the smallest possible distance from each other. For vehicle windows, which typically have a width greater than height, the busbars are therefore held along both long edges of the panel, so that heating current can flow through a shorter panel height path. This implementation, however, leads to the fact that the rest area or stopping place of the wipers provided for the car windows is usually outside the heating field, so that there is not enough heating power and the wipers can freeze.

There was no shortage of attempts to solve this serious problem.

Thus, European patent application EP 0524527 A2 discloses a windshield equipped with an electric heating layer, in which two flat heating strips are provided as heating elements in the area of ​​the wiper stop. The heating strips are electrically connected through the lower busbar, adjacent to the bottom edge of the panel, with one pole and through the wire with the other pole of the voltage source. The disadvantage of this design is that the lower busbar is additionally loaded with current for both heating strips.

In addition, the German patent application DE 102007008833 A1 and the international patent application WO 2008/104728 A2 disclose an electrically heated windshield, which can be additionally heated in the area where the wipers stop. For this, heating wires are provided, which are connected to the lower busbar as a ground terminal. Heating wires irrespective of glass heating in the field of view are loaded with potential. And in this arrangement, the lower busbar is additionally loaded with current for heating wires.

In European patent EP 1454509 B1 and US patent US 7026577 B2 proposed a transparent panel in which a heated field of view is enclosed between two busbars. In this case, the field of view is separated from the additional heating region by means of one of both busbars and, in particular, by means of a region with a removed layer. In the additional heating area, additional busbars of opposite polarity are provided to heat the panel in the masked area below the field of view.

International patent application WO 2011/141487 A1 proposes a transparent panel with a transparent heated coating that extends over at least part of the surface of the panel, in particular along its field of view. The heated coating by means of at least one non-coated zone is divided into at least one first heated coating zone and a second heated coating zone, both heating coating zones being electrically connected to at least two busbars, respectively, so that after applying a supply voltage which is provided from a voltage source, current flows respectively through at least one heating field, formed by the first zone of the heated coating, and at least one heating field formed by the second coating zone. At least one heating element is located in the non-coated zone, which has such an ohmic resistance that the panel in the surface region containing the zone without the heated coating can be heated by applying a supply voltage to the heating element. At the same time, at least one heating element is made in such a way that by applying a supply voltage to the heating element, the panel can be heated in at least one region of the surface adjacent to the uncoated zone, which contains at least one of the busbars.

Last but not least, international patent application WO 2012/110381 A1 proposes a transparent panel with an electric heating layer that extends over at least part of the surface of the panel and can be electrically connected to the source using connecting means

- 1,034,755 voltages. In this case, the connecting means comprise a tape first busbar and a tape second busbar, which are directly electrically conductively connected to the heating layer along the entire length of the tape so that when a supply voltage is applied, the heating current flows through the heating field formed by the heating layer. The first busbar with at least one first flat ribbon conductor and the second busbar with at least one second flat ribbon conductor are directly electrically conductive. In addition, the panel has at least one panel-free zone of the panel in which the at least one electric zone heating element is located. The zone heating element has such an ohmic resistance that, by applying a supply voltage, the panel zone without a heating field can be heated, and the zone heating element in electrical parallel connection to the heating field is electrically conductively connected directly to at least one first flat ribbon conductor and at least one the second flat ribbon conductor.

Although, in particular, heated transparent panels according to the international patent applications WO 2011/141487 A1 and WO 2012/110381 A1 meant a certain progress in this area, however, the increased market requirements require further improvements of previously known panels.

Thus, the design of the panel in accordance with the international patent application WO 2011/141487 A1, due to the geometry in the region of the rest state or the stop position of the wipers, can be used only in some few car models. In addition, the design with respect to changes in supply voltage and adaptation to various ohmic resistances of the heating layer is not flexible enough to meet all requirements.

A heated transparent panel according to the international patent application WO 2012/110381 A1 has the disadvantage that an additional process step is necessary in order to apply heating wires to an adhesive film, for example, from polyvinyl butyral (PVB). Because of this additional step of the method, it is necessary to manipulate the adhesive film before lamination, which leads to a higher frequency of defects caused by contamination, and thereby a higher percentage of rejects.

From European patent EP 1626940 B1, heated glass is known to prevent condensation of water. The glass comprises at least one of its sides a resistive layer or a heating layer that includes a plurality of slots / recesses, so that the glass receives a predetermined desired electrical resistance. In this case, the resistive layer or the heating layer is divided by cuts / recesses into many interconnected areas. In addition, the cuts / grooves can be of such a kind that they form corresponding regions of different geometric texture, which therefore have different resistances and, therefore, different heating effects. Slots / grooves can be performed using laser technology or by grinding. Glasses are mainly used in freezers, as they are usually used in bars, pastry shops or supermarkets. The disadvantage here is that the resistive layer or heating layer must be located between at least two busbars or collector electrodes, so that outside the busbar-limited resistive layer or heating layer there is or can only be a low heating power. The question of whether these known heated glasses are suitable for heating the resting state region or the stop position of the wipers or not cannot be resolved on the basis of this European patent. To this it should be added that from FIG. 3 of the mentioned European patent it is impossible to draw a clear conclusion regarding the course of the conductive paths, because the two opposing long busbars are also divided by slots / recesses into two areas that are electrically isolated from each other.

Other windscreens with electrically heated coatings and special measures for heating the wiper cleaning sector are known from documents WO 2011/141487 Al, WO 03/051088 A2, US 5877473 and EP 0524537 A2.

In contrast, an object of the present invention is to advantageously improve known heated, transparent panels with an electric heating layer and heating of a resting state or a wiper stop position (hereinafter referred to as a wiper stop zone). Improved heated transparent panels should have a wiper stop zone heating, which can be performed at low cost, while its implementation should easily adapt to different ohmic resistances of the electric heating layer and various supply voltage levels.

These and other tasks in accordance with the proposal according to the invention are solved by a heated transparent panel with the features of an independent claim. Other preferred embodiments of the present invention are characterized by the features of the dependent claims.

In a preferred embodiment of the panel according to the invention, the surface of the first panel on which the electrically heated coating is placed is connected via a thermoplastic intermediate layer to the second panel in a plane.

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As the first and possibly second panel, in principle, all electrically insulating substrates are suitable, which are thermally and chemically stable, as well as dimensionally stable under the conditions of manufacture and use of the panel according to the invention.

The first panel and / or the second panel preferably comprise glass, particularly preferably sheet glass, polished sheet glass, quartz glass, borosilicate glass, sodium-calcium silicate glass or transparent plastics, preferably hard transparent plastics, especially polyethylene, polypropylene, polycarbonate, polymethyl methacrylate, polystyrene, polyamide, polyester, polyvinyl chloride and / or mixtures thereof. The first panel and / or the second panel are preferably transparent, especially for using the panel as a windshield or rear window of a car or other applications in which high light transmission is desired. As transparent in the context of the present invention is understood a panel that has a transmittance in the visible region of the spectrum> 70%. For panels that are not located in the driver's field of view relevant to traffic, such as roof glass, the transmittance can be significantly lower, for example> 5%.

The thickness of the panel according to the invention can vary within wide limits and, thus, adapt well to the requirements of a particular case. Preferably, panels with a standard thickness of 1.0 to 25 mm, preferably 1.4 to 2.5 mm, are used for automotive glass and preferably 4 to 25 mm for furniture, appliances and buildings, in particular for electric heaters. The size of the panel can vary within wide limits and depends on the size in the application of the invention. The first panel and, possibly, the second panel have, for example, in the automotive industry and the architectural field ordinary areas from 200 cm² up to 20 m².

The panel according to the invention may have any three-dimensional shape. Preferably, the three-dimensional shape has no shadow areas, so that it can be coated, for example by cathodic spraying. Preferably, the substrates are flat or slightly or strongly curved in one direction or in several directions in space. In particular, flat substrates are used. The panels may be colorless or colored.

Several panels are interconnected by at least one intermediate layer. The intermediate layer preferably contains at least one thermoplastic plastic, preferably polyvinyl butyral (PVB), ethylene vinyl acetate (EVA) and / or polyethylene terephthalate (PET). The thermoplastic intermediate layer may also contain, for example, polyurethane (PU), polypropylene (PP), polyacrylate, polyethylene (PE), polycarbonate (PC), polymethyl methacrylate, polyvinyl chloride, polyacetate resin, injection resins, fluorinated ethylene-propylene copolymers, polyvinyl fluoride and / or ethylene-tetrafluoroethylene copolymers and / or copolymers or mixtures thereof. The thermoplastic intermediate layer may be formed by one or more thermoplastic films superimposed on each other, and the thickness of the thermoplastic film is preferably from 0.25 to 1 mm, usually 0.38 or 0.76 mm

In the inventive multilayer panel of the first panel, the intermediate layer and the second panel, an electrically heated coating can be applied directly to the first panel or applied to the carrier film or to the intermediate layer itself. The first panel and the second panel respectively have an inner side surface and an outer side surface. The surfaces of the inner side of the first and second panels face each other and are connected to each other through a thermoplastic intermediate layer. The surfaces of the outer side of the first and second panels face away from each other and from the intermediate thermoplastic layer. An electrical conductive coating is applied to the surface of the inner side of the first panel. Of course, an additional electrically conductive coating can also be applied to the surface of the inner side of the second panel. The surfaces of the outside of the panels may also have coatings. The terms first panel and second panel are selected to distinguish between both panels in the case of a multilayer panel according to the invention. No statement regarding the geometric arrangement is associated with these terms. If the panel according to the invention is, for example, provided in order to separate the interior from the external environment in the opening of, for example, a vehicle or building, the first panel may face the interior or the external environment.

The transparent panel according to the invention comprises an electrically conductive heated transparent coating that extends over at least a substantial part of the surface of the panel, in particular along its field of view. The electrically conductive coating is electrically connected to at least two, especially two collector electrodes, for electrically connecting to both poles of the voltage source, so that by applying a supply voltage, a heating current flows through a heating field formed between both collector electrodes. As a rule, both collector electrodes are made respectively in the form of a strip or tape electrode or busbar for introducing and wide distribution of current in the conductive coating. To this end, they are galvanically connected to the heating layer.

At least one, especially one of both collector electrodes, especially the upper collector electrode in the mounted state of the transparent panel, can be separated by at least

- 3 034755 in at least two, especially two separate partial regions.

In a preferred embodiment, the collector electrode is a conductive structure made by printing and firing. The printed collector electrode preferably contains at least metal, a metal alloy, a metal compound and / or carbon, particularly preferably a noble metal and especially silver. The printing paste for the manufacture of the collector electrode preferably contains metal particles and / or carbon, and especially noble metal particles, such as silver particles.

Conductivity is preferably achieved using electrically conductive particles. The particles may be in an organic and / or inorganic matrix, such as pastes or inks, preferably in the form of a glass frit printing paste.

The layer thickness of the printed collector electrode is preferably from 5 to 40 μm, particularly preferably from 8 to 20 μm, and most preferably from 8 to 12 μm. Printed collector electrodes with these thicknesses are technically simple to implement and have a preferred permissible current load.

Resistivity p_a the collector electrode is preferably from 0.8 to 7.0 μΩ-cm, and particularly preferably from 1.0 to 2.5 μΩ-cm. Collector electrodes having resistivity in this range are technically simple to implement and have a preferred permissible current load.

Alternatively, the collector electrode may also be in the form of a strip or, in the case of a collector electrode divided into separate partial regions, in the form of at least two, especially two, bands of an electrically conductive film. The collector 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 to 500 microns, particularly preferably from 30 to 300 microns. Collector electrodes made of an electrically conductive film with these thicknesses are technically simple to implement and have a preferred permissible current load. The strip may be electrically conductive to the electrically conductive structure, for example through solder, electrically conductive glue, or by direct application.

The electrical conductive coating of the panel according to the invention can be divided into a heating field, i.e. the heated portion of the electrical conductive coating that is located between the two collector electrodes, so that a heating current can be introduced, and a region outside said heating field.

Electrically heated coatings are known from DE 202008017611 U1, EP 0847965 B1 or WO 2012/052315 A1. They usually contain a functional layer or several, for example two, three or four, conductive functional layers. The functional layers preferably contain at least one metal, such as silver, gold, copper, nickel and chromium, or a metal alloy. Functional layers particularly preferably contain at least 90% by weight of the metal, especially at least 99.9% by weight of the metal. Functional layers can be made of metal or a metal alloy. Functional layers particularly preferably contain silver or a silver-containing alloy. Such functional layers have a particularly preferred electrical conductivity in combination with high transmittance in the visible region of the spectrum. The thickness of the functional layer is preferably from 5 to 50 nm, more preferably from 8 to 25 nm. In this range of thicknesses of the functional layer, a preferably high transmittance in the visible region of the spectrum and an especially preferred electrical conductivity are achieved.

As a rule, at least one dielectric layer is respectively arranged between two adjacent functional layers of the electrically conductive coating. In a preferred embodiment, an additional dielectric layer is arranged below the first and / or above the last functional layer. The dielectric layer comprises at least one single layer of a dielectric material, for example a nitride, such as silicon nitride, or an oxide, such as alumina. The dielectric layer may also include several separate layers, for example, separate layers of dielectric material, smoothing layers, matching layers, blocking layers and / or antireflection layers. The thickness of the dielectric layer is, for example, from 10 to 200 nm.

This multilayer structure is usually obtained by a sequence of deposition processes that are carried out by a vacuum method, such as cathodic sputtering in a magnetic field.

Other suitable electrically conductive coatings preferably comprise fluorine doped tin oxide (SnO) indium tin oxide (ITO)₂: F) or doped with aluminum oxide of zinc (ZnO: Al).

The conductive coating may in principle be any coating with which electrical contact is to be made. If the panel according to the invention is to provide visibility, such as in glasses in the window region, the electrically conductive coating is preferably transparent. The conductive coating is preferably transparent to electromagnetic radiation, particularly preferably for electromagnetic radiation with a wavelength of 300 to 1300 nm, and especially for visible light.

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In a preferred embodiment, the electrically conductive layer is a layer or a multilayer structure of several separate layers with a total thickness of less than or equal to 2 microns, particularly preferably less than or equal to 1 micron.

A preferred electrically conductive coating has a surface resistance of from 0.4 to 10 ohms / p. In a particularly preferred embodiment, the electrically conductive coating according to the invention has a surface resistance of from 0.5 to 1 Ohm / p. Coatings with such surface resistances are particularly suitable for heating automobile windows at typical on-board voltages from 12 to 48 V or electric vehicles with typical on-board voltages up to 500 V.

The conductive coating may extend over the entire surface of the first panel. Alternatively, the electrical conductive coating may only extend over a portion of the surface of the first panel. The electrical conductive coating preferably lasts at least 50%, particularly preferably at least 70% and most preferably at least 90% of the inner surface of the first panel.

In a preferred embodiment of the transparent panel according to the invention, as a multilayer panel, the surface of the inner side of the first panel has a peripheral edge region with a width of 2 to 50 mm, preferably 5 to 20 mm, which is not provided with an electrically conductive coating. The electrically conductive coating then has no contact with the atmosphere and is preferably protected from damage and corrosion by the thermoplastic intermediate layer inside the panel.

In the transparent panel according to the invention, the heating field comprises at least one uncoated area in which there is no electrically conductive coating. The uncoated zone is limited, at least in areas, to the edge of the zone formed by the electrically conductive coating.

In particular, the uncoated zone has a peripheral edge of the zone that is completely formed by the electrically conductive coating.

However, the edge of the zone may extend into the peripheral edge of the coating of the electrically conductive coating, so that the uncoated area is directly connected to the surrounding edge of the panel that is not coated with the edge strip of the transparent panel of the invention.

A non-coated zone may have various contours. So, the contour can be square, rectangular, trapezoidal, triangular, pentagonal, hexagonal, heptagonal or octagonal with rounded corners and / or curved edges, as well as circular, oval, teardrop or elliptical. Contour lines can be straight, wavy, zigzag and / or sawtooth. Some of these geometric features can be implemented in the same uncoated area.

In particular, the uncoated area serves as a communication window that is transparent to electromagnetic radiation, especially infrared radiation, radar radiation and / or radio communication radiation. In addition, sensors, such as rain sensors, can also be placed in the communication window.

An uncoated zone can be obtained, for example, by masking when applying the heating layer to the substrate or by removing the heating layer, for example by mechanical and / or chemical removal and / or removal by irradiation with electromagnetic radiation, in particular laser irradiation, after application electrically heated coating.

In a preferred embodiment, there is at least one uncoated area. Preferably there are at least two and especially at least three uncoated zones.

Preferably, at least one uncoated area or at least one communication window is placed in a mounted state of the transparent panel in its upper region.

Collector electrodes and / or their partial regions establish contact by means of one or more lead wires.

The lead wire is preferably made in the form of a flexible film conductor, or a flat conductor, or a flat ribbon conductor. By this is meant an electrical conductor, the width of which is significantly greater than its thickness. Such a flat conductor is, for example, a strip or strip containing or consisting of copper, tinned copper, aluminum, silver, gold or their alloys. The flat conductor has, for example, a width of 2 to 16 mm and a thickness of 0.03 to 0.1 mm. The flat conductor may have an insulating, preferably polymeric, jacket, for example, on a polyimide basis. Flat conductors that are suitable for contact with electrically conductive coatings in panels have a total thickness of only, for example, 0.3 mm. Such thin flat conductors can be embedded easily between individual panels in a thermoplastic intermediate layer. In a flat ribbon conductor there may be several electrically isolated conductive layers.

Alternatively, thin metal wires can be used as an electrical lead wire. Metal wires contain, in particular, copper, tungsten, gold, silver or aluminum, or alloys of at least two of these metals. Alloys may also contain molybdenum, rhenium, osmium, iridium, palladium or platinum.

In a preferred embodiment of the transparent plate according to the invention, each of at least two, especially two collector electrodes, are electrically conductively connected by a respective flat conductor to the poles of the voltage source.

In another preferred embodiment, at least two, especially two partial regions of at least one, especially one collector electrode, are electrically conductively connected to a corresponding flat conductor connected to a voltage source. Preferably, the flat conductors are located on a portion of partial regions that are located near the corresponding second side of the edge of the panel. In this embodiment, the electrical isolation of the flat conductors from the power lines is achieved through the spatial separation of the components.

In another preferred embodiment, at least two, especially two partial regions of at least one, especially one collector electrode, are electrically conductive to a flat conductor. Preferably, in this embodiment, the flat conductor is centered between both opposite ends of the partial regions. Preferably, this is achieved using a common electrically conductive connecting part or two electrically conductive connecting parts associated with the corresponding partial region. The flat conductor can be connected to the electrically conductive connecting part using a flat metal strip, in particular a copper strip.

Moreover, the flat conductor, and at least one connecting part, and, if necessary, a flat metal strip, in particular a copper strip, are located in an electrically isolated manner from at least two power lines.

In this case, the electrical insulation between the flat conductor and the connecting part on the one hand and at least two power lines on the other hand is carried out using an electrical insulating layer, especially with a strip of electrical insulating layer between the flat conductor and the connecting part, on the one hand, and at least at least two power lines, on the other hand. The electrical insulating layer, in particular the strip electrical insulating layer, covers at least the intersection points of the connecting part with at least two power lines . However, it can also be adjacent to both opposite end edges of the partial regions.

Preferably, this arrangement has a generally layered structure of the following layers superimposed on each other:

a panel, insulated sections of power lines adjacent to the power lines, partial coating areas outside the heating field, to the edges of the zones of which are adjacent the opposite edges of the insulating layer; moreover, these edges can adjoin opposite end faces of both partial regions of the collector electrode, a flat conductor adjacent to the electrically insulating layer, partial regions of the collector electrode and a connecting part electrically connected to them.

A significant advantage of this arrangement is that only a flat conductor is needed to power two partial regions of the collector electrode, which greatly simplifies the manufacture of a transparent panel according to the invention.

For the transparent panel according to the invention, it is important that it is outside the heating field and separated from it by at least one, especially one of the above collector electrodes along at least one, especially one first side of the panel edge, has at least one additional especially one heated conductive coating of the above type. Preferably, this additional heated conductive coating in the mounted state of the panel of the invention is located below the lower collector electrode and / or above the upper collector electrode in the wiper stop zone.

In this additional heated electrically conductive coating, at least one additional electrode is respectively arranged in the region of both second sides of the panel edge. Preferably, these at least two additional electrodes in the mounted state of the panel of the invention are vertically oriented. They are connected respectively through at least one, especially one power supply line, to a collector electrode, which has a polarity opposite to that of the nearest collector electrode. This means that when the upper collector electrode is electrically connected to the positively charged pole of the voltage source, both additional electrodes located above the upper collector electrode are electrically connected through the power lines to the negatively charged

- 6 034755 lower collector electrode. If, on the contrary, the additional electrodes are located in the lower additional heated electrically conductive coating below, for example, the negatively charged lower collector electrode, then they are electrically connected through the power supply lines to the positively charged upper collector electrode. The specialist should be aware of other configurations based on the proposed technical solution.

Preferably, the additional electrodes and power lines are much longer than wide. The length depends mainly on the size of the panel according to the invention. Preferably, the width is from 10 μm to 10 mm, in particular from 10 μm to 1 mm. They preferably have the same thickness as the collector electrodes.

More preferably, the power lines along their entire length have a constant thickness and width.

Power lines run along the corresponding associated edge of the coating and along both second sides of the edge of the panel, at least in areas in the associated edge strip, in the associated area of ​​the peripheral edge of the coating with electrical isolation from the heating field by, respectively, at least one associated without coating the line and / or in and / or on, respectively, associated electrical conductive coating outside the heating field when electrically isolated from the heating field by means of at least one associated uncoated line.

Preferably, the power lines extend on a correspondingly associated conductive coating outside the heating field.

Preferably, the power lines, at least in the sections, are rectilinear, wavy, tortuous, sawtooth and / or zigzag. Preferably, the power lines extend straight along their entire length.

According to the invention, the panel has at least one, especially at least one additional heated, electrically conductive coating, at least one, especially at least two associated with the respective two additional electrodes counter electrode (s) electrically connected to the associated collector electrode of opposite polarity . The term connected in the sense of the invention should be interpreted as being electrically connected through an electrically conductive coating.

Preferably, the complementary electrodes opposite each other and the counter electrodes opposite each other with respect to the center line or mirror symmetry axis of the panel according to the invention are arranged in mirror image.

The panel according to the invention also contains in at least one, especially one additional heated electrically conductive coating, at least two, especially two located in a mirror image (especially in a mirror image relative to the center line and the mirror axis of symmetry of the transparent panel) to each other from at least four, preferably at least five, uncoated lines that are arranged in this way that when a supply voltage is applied, they direct the heating current flowing from at least two additional electrodes through at least one, preferably at least two counter electrode associated with them, to at least one collector electrode of correspondingly opposite polarity, without coating lines establish conductive paths a_n and their length.

An additional electrode is directly connected to the busbar via the power line. In contrast, the counter electrode is not directly connected to another busbar of opposite polarity. Therefore, the so-called pro-electrode is not actually an electrode as such, but is a connecting conductor that interconnects two segments of the coating, which are formed by uncoated lines, so that a current can flow between the segments of the coating.

Current flow of all conductive paths a₁-a_n excited 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 non-coated lines, as well as the connection of the segments by means of the counter electrode (s) / connecting conductors, serve as the direction of current flow in the form of conductive paths a₁-a_n.

In accordance with the invention for conductive paths a_n in a system of uncoated lines, the relation I:

Vh₁= h₁: b_n= from 0.5 to 2.0, preferably from 0.75 to 1.5, and especially from 0.8 to 1.2 (I) where VH₁ denotes a mathematical relation (h₁; b_n), n is an integer from 2 to 30, preferably from 2 to 25, and especially from 3 to 20. h₁ indicates the height of the conductive path a₁b_n - the width of the conductive path a_n.

Height h₁ conductive path a₁ is the imaginary distance that is located

- 7 034755 vertically to the direction of current flow between two limiting, not having coverage lines; a₁ is a conductive path from the additional electrode to the nearest, opposite portion of the counter electrode (connecting conductor); and₂ to a_n denote other conductive paths. Using a₁-a_n conductive paths themselves or their lengths may also be indicated.

Width b_n conductive path a_n is an imaginary distance that is vertical to the direction of current flow between two limiting, uncoated lines.

Preferably width b_n located parallel or approximately parallel, preferably in an imaginary angle of ± 30 °, preferably ± 20 °, and in particular ± 10 °, relative to each other.

The ratio of the lengths of individual conductive paths a₁ to a_n has no effect on the specific heating power in these sections of the conductive tracks. The specific heating power is affected only by the total length, i.e. total resistance of conductive tracks (a₁+ a₂+ a₃+ ... a_n), as well as the ratio VH₁ width of sections.

Uncoated lines extend, at least in sections, continuously and / or as broken lines with discrete cuts. Preferably, they extend continuously along their entire length, i.e. without cuts.

The length of the lines without coating can vary within wide limits and, therefore, adapt in a preferred way to the requirements of a particular case. The width of uncoated lines is much smaller than their length, and can vary in length. Preferably, the width over the entire length is constant. Preferably, the width is in the range of 10 μm to 1 mm.

Using this system, at least two conductive paths an are determined from at least four uncoated lines in the corresponding lower and / or upper, especially lower, additional heated electrically conductive coating (s). When a supply voltage is applied in this system, a heating current flows from at least one additional electrode through at least one counter electrode (connecting conductor) along the conductive paths to the lower and / or upper collector electrode (s).

Moreover, a particular advantage of the system according to the invention is that due to this, the lower and / or upper additional heated (s) electrically conductive (s) coating (s) is heated or heated evenly, and the specific heating power is from 300 to 900 W / m²preferably 350 to 800 W / m².

Another special advantage of the configuration of additional electrodes, counter electrodes (connecting conductors) and uncoated line systems is that the entire configuration can be adapted to the requirements of a particular case in a simple way by simple parallel shifts, for example, additional electrodes and / or counter electrode ( connecting conductor) without adverse changes in the specific heating power, for example due to hot spots and / or cold spots. The optimal configuration for a particular case can be easily determined using conventional and well-known simulation programs.

In general, the configuration of the panel according to the invention, also at especially low temperatures <0 ° C, in particular <-10 ° C, very effectively prevents the freezing of inactive wipers in the wiper stop zone.

In a preferred embodiment of the transparent panel according to the invention, the areas in which collector electrodes, a flat conductor or flat conductors are placed, an additional electrode or additional electrodes, power lines and a system of lines that are not coated are partially or completely optically masked by conventional and known optically coating, opaque or non-translucent masking stripes. A masking band covers these and other functional elements in these areas and protects them from UV radiation, which can damage the functional elements. In particular, the black masking strip contains an optically covering, opaque partial region, which at its edge passes into an optically partially transparent partial region. An optically partially transparent partial region is, for example, a dot pattern. Preferably, a masking strip is applied to the inside, i.e. on the side of the outer panel facing the inner panel, by screen printing and fired, before both panels with the adhesive layer are connected to each other.

Preferably, the precursors of the masking strips are screen printed on uncoated panels, after which the applied layers are fired.

Corresponding to the invention, the panels can be manufactured in the usual and known manner. Preferably they are made using the method of the invention.

Corresponding to the invention, the method includes the following steps of the method:

(A) fabrication of an electrically conductive coating;

(B) manufacturing at least one uncoated communication window in an electrically conductive coating of a heating field;

- 8 034755 (C) the execution (cl) of at least two collector electrodes connected to both poles of the voltage source, which are electrically connected to the electrically conductive coating, so that when a supply voltage is applied, the heating current flows through the heating field located between the two collector electrodes, and / or (c2) at least two collector electrodes connected to both poles of the voltage source, which are electrically connected to the electrically conductive coating, moreover, at least one of both collector electrodes is made divided into at least two partial regions spatially separated from each other;

(D) manufacturing (d1) at least two additional electrodes, in a mirror image, opposite each other relative to the center line (and the axis of mirror symmetry) of the transparent panel;

(d2) at least two counter electrodes (connecting conductors), in a mirror image opposite each other relative to the center line (and the axis of mirror symmetry) of the transparent panel and electrically associated with additional electrodes that are electrically connected (i.e., electrically connected through an electrically conductive coating) to a collector electrode of opposite polarity;

(d3) at least two power lines located in a mirror image to each other relative to the center line (and the axis of mirror symmetry) of the transparent panel, connecting respectively at least one additional electrode with at least one collector electrode or at least at least one of its partial areas, which are along the respectively associated edge of the coating and along both second sides of the edge of the panel, at least in the sections, extend in the correspondingly associated edge strip, in the associated section of the peripheral edge of the coating during electrical isolation from the heating field by means of at least one associated uncoated line and / or in the correspondingly associated electrical coating outside the heating field during electrical isolation by means of at least one associated uncovered line;

(E) performing (e1) at least two uncoated lines running along power lines on the side of the heating field, and (e2) at least two systems of at least four uncoated lines, respectively, in mirror image of opposing friend, which are arranged in such a way that they, when applying a supply voltage, direct the heating current flowing from at least two additional electrodes, through at least two conductive paths a_nand through at least two counter electrodes (connecting conductors) respectively associated with them to at least one collector electrode, respectively, of opposite polarity, and for conductive paths a_n in a system of uncoated lines, the relation I:

Vh₁= h₁: b_n= from 0.5 to 2.0, preferably from 0.75 to 1.5, and especially from 0.8 to 1.2 (I), with n being an integer from 2 to 30, preferably from 2 to 25, and especially from 3 to 20, (a₁) denotes the conductive path from the additional electrode to the nearest opposite portion of the counter electrode (connecting conductor), (h₁) denotes the height of the conductive path a₁, (a ^. ^^ denotes other conductive paths, b_n indicates the width of the conductive path a_n, and (VH₁) denotes the mathematical relation (h₁: b_n);

(F) wherein steps (B) and (E) of the method are performed sequentially or simultaneously;

(G) wherein steps (C) and (D) of the method are performed simultaneously or sequentially, as well as before or after steps (B) and (E) of the method.

Ratios of the lengths of individual conductive paths a₁ to a_n have no effect on the specific heating power in these sections of the conductive track. The specific heating power is affected only by the total length, i.e. total resistance of conductive tracks (a₁+ a₂+ a₃+ ... a_n), as well as the ratio VH₁ width of sections.

In a preferred embodiment of the method according to the invention, at least four uncoated lines are produced, as well as at least two systems using laser ablation of an electrically conductive coating inside and outside the heating field.

In yet another preferred embodiment, steps (C) and (D) of the method are performed by screen printing.

- 9 034755

In more detail, the deposition of an electrically conductive coating in step (A) of the method can be carried out in a known manner, preferably by cathodic sputtering in a magnetic field. This is particularly advantageous from the point of view of a simple, quick, economical and uniform coating of the first panel when the panel according to the invention is made in the form of a multilayer panel. The electrically conductive heated coating may also be applied, for example, by spraying, chemical vapor deposition (CVD), plasma chemical vapor deposition (PECVD), or liquid chemical methods.

The first panel after step (A) of the method may be subjected to heat treatment. In this case, the first panel with an electrically conductive coating is heated to a temperature of at least 200 ° C, preferably at least 300 ° C. Heat treatment can serve to increase the transmission and / or decrease the surface resistance of the electrically conductive coating.

The first panel after step (A) can be bent, as a rule, at a temperature of from 500 to 700 ° C. Since it is technically easier to coat a flat panel, this approach is preferred if the first panel is to be curved. Alternatively, the first panel may also be bent before step (A) of the method, for example when the electrically conductive coating is not suitable to withstand the bending process without damage.

The application of collector electrodes in step (C) of the method and power lines in step (E) of the method is preferably carried out by printing and firing the conductive paste in a screen printing method or an ink jet method. Alternatively, collector electrodes and power lines can be applied as stripes of an electrically conductive film to an electrically conductive coating, preferably applied, soldered, or glued.

In the screen printing method, lateral formation is carried out by masking a fabric through which a printed paste with metal particles is pressed. By suitable masking, for example, the width of the collector electrode can be set and changed especially easily.

Uncoated zones are made in step (B) of the method, preferably by mechanical removal of the heated coating produced in step (A). Mechanical removal can also be replaced or supplemented by treatment with suitable chemicals and / or electromagnetic radiation.

A preferred development of the method according to the invention includes at least the following additional steps:

placing the thermoplastic intermediate layer on the coated surface of the first panel and placing the second panel on the thermoplastic intermediate layer and connecting the first panel and the second panel through the thermoplastic intermediate layer.

At these stages of the method, the first panel is placed so that one of its surfaces, which is provided with a heated coating, faces the thermoplastic intermediate layer. Thus, the surface becomes the surface of the inner side of the first panel.

The thermoplastic intermediate layer can be made by means of one separate or two or more thermoplastic films, which are located one above the other in area.

The connection of the first and second panels is preferably effected by heat, vacuum and / or pressure. Known methods for manufacturing the panel may also be used.

For example, the so-called autoclave methods can be carried out at elevated pressures from 10 to 15 bar and temperatures from 130 to 145 ° C for about 2 hours. Known methods for forming with a vacuum bag or a vacuum ring per se operate, for example, at a pressure of about 200 mbar and temperature from 80 to 110 ° С. The first panel, the thermoplastic intermediate layer and the second panel can also be pressed on a calender between at least one pair of rolls to form a panel. Installations of this type for the manufacture of panels are known and, as a rule, have at least one heating tunnel in front of the press shop. The temperature during the pressing process is, for example, from 40 to 150 ° C. The combination of calendaring and autoclave methods have proven themselves in practice. Alternatively, vacuum laminators can be used. They consist of one or more heated and evacuated chambers in which the first panel and the second panel are laminated, for example, for about 60 minutes at reduced pressures from 0.01 to 800 mbar and temperatures from 80 to 170 ° C.

The transparent panel according to the invention, especially the transparent panel made according to the invention, can be successfully used as a functional and / or decorative separate item and as an embedded part in furniture, appliances and buildings, as well as in vehicles for movement on the ground, in the air or by water, especially in automobiles, for example as a windshield, rear window, side window and / or roof glass. Preferably, the transparent panel according to the invention is configured as a car windshield or a car side window.

It is understood that the features mentioned above and explained below can be used not only in the indicated combinations and configurations, but also in other combinations and configurations, or alone

- 10 034755 without deviating from the scope of the present invention.

Brief Description of the Drawings

The invention will now be explained in more detail with reference to the accompanying drawings, in which, in simplified and not to scale, the following is presented.

FIG. 1A is a plan view of a simplified representation of a windshield 1 according to the invention.

FIG. 2 is a vertical sectional view of a fragment of a windshield according to the invention according to FIG. 1.

FIG. 3 is a perspective view of a fragment of a windshield according to the invention according to FIG. 1.

FIG. 4 is a plan view of a detailed fragment B of the windshield 1 of the invention according to FIG. 1.

FIG. 5 is a plan view of a detail fragment A of an exemplary embodiment of a windshield 1 according to the invention according to FIG. 1.

FIG. 6 is a plan view of a detail fragment A of another exemplary embodiment of the windshield 1 of the invention according to FIG. 1 along with enlarged fragment C.

FIG. 7 is a top view of a detail fragment A of another exemplary embodiment of the windshield 1 of the invention according to FIG. 1 together with an enlarged fragment D.

FIG. 8 is a top view of a detailed fragment of yet another exemplary embodiment of a windshield 1 according to the invention.

Detailed Description of Drawings

FIG. 1 in conjunction with FIG. 2, 3 and 4.

FIG. 1 shows a transparent windshield 1 of a car from the inside in a simplified view. The windshield here is made, for example, in the form of a multilayer panel, the structure of which is illustrated by representing a vertical section of a fragment of the windshield 1 in FIG. 2 and using a perspective view of a fragment of the windshield 1 in FIG. 3.

Accordingly, the windshield 1 consists of two rigid separate panels, namely the outer panel 2 and the inner panel 3, which are firmly bonded to each other by means of a thermoplastic adhesive layer 4, here, for example, polyvinyl butyral (PVB) film, ethylene-vinyl acetate film (EVA) or polyurethane film (PU). Both individual panels 2, 3 have approximately the same size and shape and can, for example, have a trapezoidal curved contour, which is not shown in detail in the drawings. They are made of, for example, glass and they can also be made of non-glass material, such as plastic. For other applications as windscreens, it would also be possible to fabricate both separate panels 2, 3 from a flexible material. The contour of the windshield 1 is formed by a panel edge 5 common to both separate panels 2, 3, wherein the windshield 1 has two opposite sides of the first side 6, 6 ′ on top and bottom, and two second sides of the opposite side 7, left and right, 7 '.

As shown in FIG. 2 and 3, on the side of the inner panel 3 connected to the adhesive layer 4, a transparent electrically conductive coating is applied 8. The heated electrically conductive coating 8 is applied here, for example, over substantially the entire area of ​​the inner panel 3, and the edge strip 9 surrounding on all sides does not have coating, so that the edge 10 of the coating of the conductive coating 8 with respect to the edge 5 of the panel is shifted inward. Thus, electrical insulation of the electrical conductive coating 8 with respect to the outside is achieved. In addition, the conductive coating 8 is protected from corrosion penetrating from the edge 5 of the panel.

The electrically conductive coating 8 in a known manner contains a sequence of layers not shown, including at least one electrically heated metal partial layer, preferably silver, and optionally other layers, such as antireflection and blocking layers. Preferably, the sequence of layers has high thermal stability, so that it can withstand the temperatures required to bend glass panels, typically more than 600 ° C, without damage, but sequences of layers with lower thermal stability can also be provided. The electrically conductive coating 8 may also be applied as a single metal layer. In addition, it is possible to apply the electrically conductive coating 8 not directly to the inner panel 3, but first to apply it to a substrate, such as a plastic film, which is then bonded to the outer and inner panels 2, 3. Alternatively, the carrier film can be connected to adhesive films ( for example, with PVB films) and in the form of a three-layer structure stick together with the inner and outer panels 2, 3. The electrically conductive heated coating 8 is preferably applied by sputtering or magnetron-cathode sputtering onto an inner or outer panel 2, 3.

As shown in FIG. 1, an electrically conductive coating 8 adjacent to the first sides 6, 6 ′, i.e. at the upper and lower edges 5 of the panel, electrically conductively connected to the tape upper collector electrode or busbar 11 and the tape lower collector electrode 11 '. The upper collector electrode 11 and the lower collector electrode 11 'are intended to be connected to the corresponding 11 034755 pole of a voltage source (not shown). Both collector electrodes 11, 11 'of opposite polarity serve for uniform input and distribution of the heating current in the heating field 12 of the heated coating 8 located between them. Both collector electrodes 11, 11', for example, are printed on the electrically conductive coating 8 and have at least approximately rectilinear shape.

But collector electrodes 11, 11 'can also be subdivided respectively into two partial regions spatially separated from each other.

The upper collector electrode 11 in the mounted state of the windshield 1 separates the heating field 12 from the partial region 8 ′ of the electrically conductive coating 8 passing along the upper first side 6 of the panel 5.

The lower collector electrode 11 'in the mounted state of the windshield 1 separates the heating field 12 from the partial region 8' passing along the lower first side 6 '. This partial region 8 'serves to heat the wiper stop zone. Additional details of various embodiments of the invention follow from fragments A in FIG. 5-9.

Below the upper collector electrode 11 there are 3 uncoated communication windows in the heating field 12, located centrally in the mirror image. Those. they are divided in half by an imaginary vertical center line M or the axis of mirror symmetry.

From both ends of the upper collector electrode 11 in the partial regions 8 of the coating 8 along the corresponding associated partial region of the edge 10 of the coating are two mirrored to each other located power lines 15, 15 'to opposing each other additional electrodes 18, 18' in the partial region 8 '. Power lines 15, 15 'and additional electrodes 18, 18' are made of the same material as the collector electrodes 11, 11 '.

The power lines 15, 15 'and additional electrodes 18, 18', respectively associated with them, extending along the power lines 15, 15 'on the side of the heating field 12 without coating lines 16, 16', are electrically isolated from the heating field 12. Uncoated lines 16, 16 'have a width of about 100 microns. They can be made preferably by laser ablation.

Uncoated lines 16, 16 'extend to the upper collector electrode 11, extend above the upper collector electrode 11 to the peripheral edge strip 9, and separate the partial regions 8 along the second sides 7, 7' and the partial region 8 'along the upper first side 6 ''. Additional details follow from fragment B in FIG. 4.

FIG. 4 shows the intersection 17 of the uncoated line 16 with the upper collector electrode 11. Preferably, this intersection 17 is created by the fact that the upper collector electrode 11 is screen printed on top of the uncoated non-coated laser ablation line 16.

FIG. 4 further shows a preferred configuration of the black masking strip 13, as it is also used in the region of the lower collector electrode 11 'and in the regions 8, 15, 16. The masking strip 13 covers the functional elements in these areas and also protects them from UV radiation, which can lead to damage to functional elements. In particular, the black masking strip 13 comprises an optically covering, opaque partial region 13 ′, which at its edge 13 passes into an optically partially transparent partial region 13 ″ ″, which itself reaches the edge 13 ″ ″. The optically partially transparent partial region 13 ″ ″ is, for example, a dot pattern. Preferably, the masking strip 13 is screen printed on the inside, i.e. on the side of the outer panel 2 facing the inner panel 3, and fired before assembly, before both panels 2 and 3 are connected to the adhesive layer 4.

FIG. 5 in conjunction with FIG. 1.

FIG. 5 shows a detailed top view of fragment A of an exemplary embodiment of the windshield 1 of FIG. 1.

Fragment A reproduces only the left partial coverage region 8 'in the area of ​​the wiper stop zone to the center line and the mirror symmetry axis M. The right partial coverage region 8 'is a mirror image of the left partial region 8', and therefore it is not necessary to reproduce it.

In this exemplary embodiment of FIG. 5, the uncoated line 16 transfers to the system 16 of a total of three horizontal uncoated lines and one vertical uncoated line with a line width of about 30 μm. In this system 16, in the left partial region 8 ', at three branching points 17, three horizontal branches are arranged parallel to each other and have no line coverage. The upper uncoated line touches the upper end 20 of the vertically placed additional electrode 18 and the vertically arranged counter electrode / connecting conductor arm 19. The middle uncoated line touches the lower end 20 of the additional electrode and ends at its end point 21 at the vertically arranged counter electrode / connecting conductor arm nineteen. The lower uncoated line extends from the branch point 17 in parallel to the lower peripheral edge

- 12 034755 coatings along the lower first side 6 'to the imaginary center line M and beyond.

The upper uncoated line extends downward from the upper end 20 of the vertical arm of the counter electrode / connecting conductor 19, intersects the horizontal arm of the counter electrode / connecting conductor 19 at the intersection 17 'and continues below the horizontal arm to the branch point 17 of the lower uncoated line.

Details of end points 20 result from enlarged fragment C in FIG. 6. Details of branch points 17 result from enlarged fragment D in FIG. 7.

Through this system 16 out of four uncoated lines, two conductive paths are formed a₁ and a₂ in a partial region of 8 '. Conducting path a₁ passes from an additional electrode 18 to the upper arm of the counter electrode / connecting conductor 19; it is, therefore, in this embodiment and in the following described embodiments, a first conductive path. A conductive path a extends from the horizontal arm of the counter electrode / connecting conductor 19₂ to the lower collector electrode 11 '. VH ratio₁= 0.9 and n = 2. When a supply voltage of 12 V is applied to the system 16, a heating current flows from the additional electrode 18 through the counter electrode / connecting conductor 19 to the lower collector electrode 11 '.

A particular advantage of this system 16, 18, 19 according to the invention is that the coating 8 'is thereby heated uniformly, and the specific heating power is from 400 to 550 W / m² Another particular advantage of the system 16, 18, 19 according to the invention is, moreover, that the entire configuration can be adapted using simple parallel transfers P, for example, an additional electrode 18 and / or a vertical arm of the counter electrode / connecting conductor 19 to the requirements of a particular case without an adverse change in the specific heating power, for example, due to the occurrence of hot spots and / or cold spots. Optimal configuration of electrodes 18, 19 and conductive paths a₁... a_n can be easily determined using conventional and well-known modeling programs.

In general, an embodiment of the transparent panel 1 according to the invention according to FIG. 5, also at particularly low temperatures <0 ° C, effectively prevents the wipers from freezing in the wiper stop zone.

FIG. 6 in conjunction with FIG. 1.

FIG. 6 shows a detailed top view of fragment A of an exemplary embodiment of the windshield 1 of FIG. 1.

As in FIG. 5, fragment A reproduces only the left partial coverage region 8 'in the area of ​​the wiper stop zone to the center line and mirror symmetry axis M. The right partial coverage region 8 'here is a mirror image of the left partial region 8', and therefore there is no need for its reproduction.

In this exemplary embodiment of FIG. 6, the uncoated line 16 transfers to the system 16 of a total of three horizontal uncoated lines and two vertical uncoated lines with a line width of about 30 μm. In this system 16, in the left partial region 8 ', at three branching points 17, three horizontal branches are arranged parallel to each other and have no line coverage. The upper uncoated line touches the upper end of the additional electrode 18. As for the details, reference can be made to enlarged fragment C in FIG. 6. Then, the uncoated line extends along the horizontal arm of the counter electrode / connecting conductor divided into two parts 19. A vertical coating line (branch point 17) branches into this region and extends to the lower horizontal uncoated line. The middle horizontal uncoated line of the system 16 touches the lower ends of the vertical additional electrode 18 and the vertical arm divided into two parts of the counter electrode / connecting conductor 19 and extends to the branch point 17 with an uncoated line along the vertical arm of the counter electrode / connecting conductor 19. Details regarding branch points 17 follow from segment D in FIG. 7.

In the region of the end of the horizontal arm of the two-divided counter electrode / connecting conductor 19, the uncoated line runs vertically downward and intersects the partial region of the counter electrode / connecting conductor spatially separated from it but electrically connected to the horizontal arm 19. The intersection point 17 'has the same configuration as the intersection point 17 in FIG. 4. A partial region of the counter electrode / connecting conductor 19 is then electrically connected to the lower collector electrode 11 ', namely, electrically connected by means of an electrically conductive coating.

Through this system, 16 out of five uncoated lines form three conductive paths a₁, a₂ and a₃. Conducting path a₁ passes from the additional electrode 18 to the vertical arm of the counter electrode / connecting conductor 19 divided into two parts. A conductive path a passes from the horizontal arm of the counter electrode / connecting conductor 19₂ to a separate horizontal partial region of the counter electrode / connecting conductor

- 13 034755

nineteen. Conducting path a₃ extends from this separate horizontal partial region 19 to the lower collector electrode 11 '.

The additional electrode 18 is connected directly to the first busbar 11 through the power supply line 15. In contrast, the counter electrode 19 is not connected directly to the second busbar 11 '. The counter electrode 19 is a connecting conductor that interconnects two segments of the coating, which are formed by uncoated lines, so that current can flow between the segments of the coating.

Current flow of all conductive paths a₁-a_n excited by the potential difference between the additional electrode 18 (connected to the first busbar 11) and the second busbar 11 '. The segmentation of the conductive coating formed with the help of non-coated lines, as well as the connection of the segments with the counter-electrodes (s) 19, serve as the direction of current flow in the form of conductive paths a₁-a_n.

VH ratio₁= 1, the ratio VH₂= 1 and n = 2 and 3. When a supply voltage of 12 V is applied to the system 16, a heating current flows from the additional electrode 18 through the counter electrode / connecting conductor 19 to the lower collector electrode 11 '. When a supply voltage of 12 V is applied to the system 16, a heating current flows from the additional electrode 18 through the counter electrode / connecting conductor 19 divided into two parts to the lower collector electrode 11 '.

A particular advantage of this system 16, 18, 19 according to the invention is that the coating 8 'is thereby heated uniformly, and the specific heating power is from 400 to 550 W / m² Another particular advantage of the system 16, 18, 19 according to the invention is, moreover, that the entire configuration can be adapted using simple parallel transfers P, for example, an additional electrode 18 and / or a vertical arm of the counter electrode / connecting conductor 19 to the requirements of a particular case without an adverse change in the specific heating power, for example, due to the occurrence of hot spots and / or cold spots. Optimal configuration of electrodes 18, 19 and conductive paths a₁... a_n can be easily determined using conventional and well-known modeling programs.

In general, an embodiment of the transparent panel 1 according to the invention according to FIG. 6 also at particularly low temperatures <0 ° C effectively prevents the wipers from freezing in the wiper stop zone.

FIG. 7 in combination with FIG. 1.

FIG. 7 shows a detailed top view of fragment A of an exemplary embodiment of the windshield 1 of FIG. 1.

As in FIG. 5 and 6, fragment A reproduces only the left partial coating region 8 'in the region of the wiper stop zone to the center line and the mirror symmetry axis M. The right partial coverage region 8 'is a mirror image of the left partial region 8', and therefore it is not necessary to reproduce it.

In this exemplary embodiment of FIG. 7, the uncoated line 16 transfers to the system 16 of a total of three horizontal uncoated lines and three vertical uncoated lines with a line width of about 30 μm. In this system 16, in the left partial region 8 ', at three branching points 17, three horizontal branches are arranged parallel to each other and have no line coverage. Of these, the upper uncoated line touches the upper end of the vertical supplementary electrode 18 and the upper end of the vertical arm of the three-piece additional electrode 19. Then, the upper uncoated line runs along the spatially separated upper partial region of the three-part counter electrode / connecting conductor 19. The upper partial region is electrically connected with the lower horizontal arm of the counter electrode divided into three parts and its third spatially separated lower partial region.

Beyond the end point 20, there is a branch 17, in which the uncoated line branches vertically downward and runs along the vertical arm of the counter electrode / connecting conductor 19 divided into three parts (see in more detail on the enlarged fragment D in Fig. 7), intersects the lower horizontal shoulder and ends at the bottom line with no coverage. In the further passage, the upper horizontal uncoated line forks again, and the branched uncoated line extends vertically downward, touches the end point 20 of the horizontal lower arm, passes through the gap between the end of the horizontal lower arm and the third horizontal partial region of the counter electrode divided into three parts / connecting conductor 19 and then meets the lower horizontal uncoated line.

The upper uncoated line runs along the horizontal upper partial region of the counter electrode / connecting conductor 19 and then bends vertically downward, touches the end of the horizontal upper partial region, intersects the horizontal lower third third part of the three-part counter electrode / connecting conductor 19 and 17 also Meets the bottom horizontal uncoated line.

- 14 034755

The horizontal lower third partial region of the counter electrode / connecting conductor 19 divided into three parts then extends further to the center line and the mirror symmetry axis M.

Through this system, 16 of the six uncoated lines form four conductive paths a_b a₂, a₃ and a₄. Conducting path a₁ passes from the additional electrode 18 to the vertical arm of the counter electrode / connecting conductor 19 divided into three parts. A conductive path a passes from the horizontal lower arm of the counter electrode 19₂ to a separate horizontal upper partial region of the counter electrode / connecting conductor 19. The conductive path a3 extends from this separate horizontal upper partial region of the counter electrode 19 to the horizontal lower partial region of the three-part counter electrode / connecting conductor 19. From there, the conductive path a4 passes to the lower collector electrode 11 '.

VH ratio₁= 1.5 and n = 2 to 4. When a supply voltage of 12 V is applied to the system 16, a heating current flows from the additional electrode 18 through the counter electrode 19 divided into three parts to the lower collector electrode 11 '.

A particular advantage of this system 16, 18, 19 according to the invention is that the coating 8 'is thereby heated uniformly, and the specific heating power is from 400 to 550 W / m² Another particular advantage of the system 16, 18, 19 according to the invention is, moreover, that the entire configuration can be adapted using simple parallel transfers P, for example, an additional electrode 18 and / or a vertical arm of the counter electrode / connecting conductor 19 to the requirements of a particular case, without adverse changes in the specific heating power, for example, due to the occurrence of hot spots and / or cold spots. Optimal configuration of electrodes 18, 19 and conductive paths a₁... a_n can be easily determined using conventional and well-known modeling programs.

In general, an embodiment of the transparent panel 1 according to the invention according to FIG. 7 also at particularly low temperatures <0 ° C effectively prevents the wipers from freezing in the wiper stop zone.

FIG. 8 in conjunction with FIG. 1.

FIG. 8 shows a detailed top view of fragment A of an exemplary embodiment of the windshield 1 of FIG. 1.

As in FIG. 5, 6 and 7, fragment A reproduces only the left partial coverage region 8 'in the region of the wiper stop zone to the center line and mirror symmetry axis M. The right partial coverage region 8 'here is also a mirror image of the left partial region 8', and therefore it is not necessary to reproduce it.

An embodiment of the windshield 1 of FIG. 8 is a further development of an embodiment of the windshield 1 of FIG. 6. The difference is based on the fact that in the embodiment according to FIG. 8, the 8 'coating in the area of ​​the wiper stop zone is divided by two horizontal and ten vertical uncoated lines into ten current paths a₁-a₁₀rather than three horizontal and three vertical uncoated lines into three conductive paths a₁-a₃.

VH ratio₁= 1.5 and n = 2 to 5. When a supply voltage of 12 V is applied to the system 16, a heating current flows from the additional electrode 18 through a counter-electrode / connecting conductor 19 divided into four parts to the lower collector electrode 11 '.

A particular advantage of this system 16, 18, 19 according to the invention is that in this way the coating 8 'is heated particularly evenly, and the specific heating power is from 500 to 700 to 0 W / m². Another particular advantage of the system 16, 18, 19 according to the invention is, moreover, that the entire configuration can be adapted using simple parallel transfers P, for example, an additional electrode 18 and / or a vertical arm of the counter electrode / connecting conductor 19 to the requirements of a particular case without an adverse change in the specific heating power, for example, due to the occurrence of hot spots and / or cold spots. Optimal configuration of electrodes 18, 19 and conductive paths a₁... a_ncan be easily determined using conventional and well-known modeling programs.

In general, an embodiment of the transparent panel 1 according to the invention according to FIG. 7 also at particularly low temperatures <0 ° C very effectively prevents the wipers from freezing in the wiper stop zone.

In FIG. 1-8 reference numbers have the following meanings:

- windshield;

- external panel;

- internal panel;

- adhesive layer;

- peripheral edge of the panel;

- upper mounted windshield 1, the first side of the edge 5 of the panel;

- 15 034755

6 '- lower in the mounted state of the windshield 1, the first side of the edge 5 of the panel;

7, 7 '- lateral in the mounted state of the windshield 1, the second side of the edge 5 of the panel;

- conductive coating;

8 '- in the mounted state of the windshield 1 located outside the heating field 12 along the lower first side 6' of the edge 5 of the panel lower conductive coating 8 in the area of ​​the wiper stop zone;

- in the mounted state of the windshield 1, partial areas of the electrical conductive coating 8 located outside the heating field 12 along the second sides 7 and 7 ′ of the panel edge 5;

8 '' '- in the mounted state of the windshield 1, a partial region of the electrically conductive coating 8 located outside the heating field 12 along the upper first side 6 of the panel edge 5;

- peripheral edge strip that does not have an electrically conductive coating 8;

- peripheral edge of the coating;

- top in mounted state of the windshield 1 collector electrode;

11 '- lower in the mounted state of the windshield 1 collector electrode;

- heating field;

- masking strip;

13 '- optically covering, opaque part of the masking strip 13;

- the edge of the optically covering, opaque partial region of the masking strip 13;

13 "" is an optically partially transparent partial region of the masking strip 13;

13 "'' 'is the edge of the optically partially transparent partial region of the masking strip 13;

- communication window that does not have an electrically conductive coating 8;

15, 15 'are power lines extending from the upper collector electrode 11 along the corresponding associated coating edge 10 in respective associated partial regions 8 to additional electrodes 18, 18';

16, 16 '- uncoated lines extending along power lines 15, 15' on the side of the heating field 12;

- a system of at least four uncoated lines in the coating 8 'in the area of ​​the wiper stop zone;

- the intersection of uncoated lines 16, 16 'with the collector electrode 11;

17 'is the intersection of the uncoated line 16 with the counter electrode 19;

- the branch point of the uncoated line 16;

18, 18 'are additional electrodes located in the lower conductive coating 8' (wiper stop zone) electrically connected through power supply lines 15, 15 'to the collector electrode 11;

- counter electrode to the additional electrode 18 (connecting conductor);

- the end point of the additional electrode 18 or counter electrode 19 on the uncoated line 16;

- the end point of the uncoated line 16 of the additional electrode 18 or counter electrode 19;

a₁ - the length of the conductive track from the additional electrode 18 to the nearest opposite portion of the counter electrode 19;

and₂, ..., a_n - the length of the conductive path;

h₁ - the height of the conductive path a₁;

b₂, ..., b_n - the width of the conductive tracks a₂ to a_n;

1 / 2b₆ - half width b₆;

A is an enlarged fragment of the windshield 1;

In - an enlarged fragment of the windshield 1;

C is an enlarged fragment of the windshield 1;

D is an enlarged fragment of the windshield 1;

M is the vertical center line and the axis of mirror symmetry;

P is a parallel shift.