WO2022214368A1

WO2022214368A1 - Electronic bridge for multiple heatable camera windows

Info

Publication number: WO2022214368A1
Application number: PCT/EP2022/058348
Authority: WO
Inventors: Thomas Gallinelli; Francois HERMANGE; Varun RAMESH KUMAR; Markus KEWITZ
Original assignee: Saint-Gobain Glass France
Priority date: 2021-04-09
Filing date: 2022-03-30
Publication date: 2022-10-13
Also published as: DE202022002762U1; CN115462177A

Abstract

The invention relates to a pane (100) with an electrically heatable sensor region (3), at least comprising: a first pane (1) with a surface (III); at least one first and second electrically heatable coating (9.1, 9.2), each of which is applied onto a part of the surface (III) and which are not in direct contact with each other; a first and a second busbar (8.1, 8.2), which are provided for connecting to a voltage source (5) and which are connected to the at least first and second electrically heatable coating (9.1, 9.2) such that a current path (14) for a heating current is formed between the first and second busbar (8.1, 8.2); and an electrically conductive heating layer (6), which surrounds the first and second heatable coating (9.1, 9.2), wherein the at least one first and second electrically heatable coating (9.1, 9.2) are connected together in an electrically conductive manner by means of at least one electrically conductive bridge (7), and the current path (14) runs at least over the first heatable coating (9.1), the electrically conductive bridge (7), and the second heatable coating (9.2). The first and second heatable coating (9.1, 9.2) are each galvanically and physically completely separated from the surrounding heating layer (6) by means of a respective coating-free separating line (10).

Description

Electronic bridge for several heated camera windows

The invention relates to a transparent pane with more than one heatable coating, a method for its production and its use.

Vehicles are increasingly equipped with various sensors or camera systems. Examples are camera systems such as video cameras, night vision cameras, residual light intensifiers, laser range finders or passive infrared detectors. Vehicle identification systems are also increasingly being used, for example, for collecting tolls.

Camera systems can use light in the ultraviolet (UV), visible (VIS) and infrared (IR) wavelength ranges. This means that objects, vehicles and people can be precisely identified even in poor weather conditions, such as darkness and fog. These camera systems can be placed in motor vehicles behind the windshield in the passenger compartment. They also offer the opportunity to recognize dangerous situations and obstacles in good time on the road.

However, due to their sensitivity to the effects of weather or relative winds, such sensors must in all cases be protected by panes that are transparent to radiation. In order to ensure optimal functioning of the optical sensors, clean and non-fogging panes are absolutely necessary. Condensation and icing impede the functionality significantly, as they significantly reduce the transmission of electromagnetic radiation. While wiping systems can be used for water droplets and dirt particles, these are usually not sufficient for icing. This requires systems that heat up the pane segment assigned to the sensor, at least for a short time, if necessary, and thus enable uninterrupted use.

Panes can therefore have an electrical heating function. Thus, laminated panes are known which have a transparent, electrically conductive coating on an inside surface of one of the individual panes. An electric current can be conducted through the electrically conductive coating by an external voltage source, which current heats up the coating and thus the pane. WO2012/052315 A1, for example, discloses such a heatable, electrically conductive metal-based coating.

The electrical contacting of the electrical heating layer typically takes place via busbars, as is known from US2007/0020465 A1. The collectors exist for example from a printed and baked silver paste. The busbars typically run along the top and bottom edges of the pane. The bus bars collect the current flowing through the electrically conductive coating and direct it to external leads that are connected to a voltage source.

The busbars running along the upper and lower edges can also be used to heat several segments of a heating layer in order to provide a more even heating power distribution. Such an arrangement is known, for example, from US2878357A1. US20120103961A1 discloses a coated and heatable pane, which is partially decoated in a locally defined area. The partially stripped area can be used as a sensor window, for example. The locally delimited area has two collector conductors, which are arranged essentially parallel to the upper edge of the pane and are connected to one another via an ohmic resistor. This can improve the homogeneity of the electric field across the disk, minimizing hot and cold spots on the disk.

The applications US20130092676A1 and US20160174295 show a segmented heating layer that has been applied over a large area to a pane. Some of the segments of the heating layers are connected to one another via an electrical bridge, this electrical bridge being in the form of strips. The segments are connected to each other in such a way that the current path between two busbars is as long as possible. This enables high electrical voltages of 100 V to 400 V to be applied, since the electrical resistance or surface power is increased. The area around the heating layer is free of electrically conductive coatings.

An example of a heating area on a pane together with a capacitive touch sensor is disclosed in US10638549B2.

A general problem with heatable coatings is their still relatively high surface resistance, which requires a high operating voltage, which is higher than the normal on-board voltages of vehicles, in any case if the pane to be heated is large or if the current paths are long. Another problem in this context is the resulting power consumption, which is also increased, due to the high voltage required. If one wanted to lower the sheet resistance, this would go hand in hand with the previously known layer systems with a reduction in the transmission of visible light, since the conductive layers would have to be thicker. This problem is particularly relevant when the sensor area is particularly large in terms of its surface area, as may be necessary when using more than one sensor, for example.

The object of the present invention is therefore to provide an improved pane with an electrically heatable sensor area, which can be heated quickly with the lowest possible voltage and power consumption.

The object of the present invention is achieved according to the invention by a pane according to independent claims 1 , 13 and 15 . Preferred embodiments emerge from the dependent claims.

The pane according to the invention with an electrically heatable sensor area comprises at least the following features: a first pane with a surface, a first and a second electrically heatable coating, a first and a second busbar provided for connection to a voltage source and an electrically conductive bridge.

The at least first and second heatable coatings are each applied to a portion of the surface and are not in direct contact with each other. The first and second busbars are connected to the at least first and second electrically heatable coating in such a way that a current path for a heating current is formed between the first and second busbars. The at least first and second electrically heatable coating are electrically conductively connected to one another by means of at least one electrically conductive bridge, the current path running at least via the first heatable coating, the electrically conductive bridge, and the second heatable coating.

In this case, the current path runs in particular over or through the first and second electrically heatable coating on the surface of the pane.

The first and the second bus bar as well as the at least first and the at least second heatable coating are arranged in a sensor area. The sensor area can comprise a first and a second sensor window, which are arranged completely within the respective first or second heatable coating. Where the first Sensor window is assigned to the first heatable coating and the second sensor window is assigned to the second heatable coating. In the context of the invention, the sensor window means the area on the pane according to the invention which is provided for an optical sensor to see through, so that optical beams which pass through the sensor window can be detected by the sensor.

Panes with an electrically heatable sensor area, which is suitable for viewing more than one sensor and in which the sensors are adjacent to one another, usually have a larger-area heatable coating than is provided for individual sensors. The heatable coating must also allow the highest possible transmission so that optical sensors can function properly. However, this often means that the electrically heatable coating is arranged as thinly as possible on or within the pane, which leads to increased electrical resistance and the associated electrical power consumption and possibly an increased electrical voltage required. This relationship is based on the formula for calculating the electrical power, which results from conversion:

In this case P is the power [W], U is the voltage [V] and R is the electrical resistance [W]. For heating a homogeneous coated surface, as is the case with the electrically heatable coating, the formula can be rewritten per unit area will:

U = L - P ^~ T _S

In this case, Ps is the power per unit area [Wnr ² ], Rs is the sheet resistance [W sq ¹ ] and L is the distance between the busbars [m]. In this context, the distance between the busbars refers to the length of the current path that forms between the busbars. So the distance between the contact points of the different busbars, which are connected to the heatable coating.

The invention is based on the finding that the electrical resistance between the first and second busbars is reduced by the arrangement of the electrically conductive bridge between the first and second heatable coating. Due to the invention, electrical power can be saved and the voltage required for Heating of the sensor area can be reduced. This benefit is particularly effective in modern electric vehicles, where increased electric power consumption is associated with reduced driving range. In classic internal combustion engines, on the other hand, a voltage that is as standardized as possible and does not exceed 14 V is desired, since otherwise additional material costs could arise, for example for the use of a DC voltage converter.

In an advantageous embodiment of the invention, the electrically conductive bridge comprises a first contact area, a second contact area and a connection area. The first contact area, the second contact area and/or the connection area are preferably in the form of strips, particularly preferably rectangular. The first contact area is connected to the first heatable coating and the second contact area is connected to the second heatable coating. The connection area spatially directly connects the first contact area to the second contact area. The first and second contact portions are connected to a length L along an edge portion of the respective first and second heatable coatings. In a plan view of the pane according to the invention, the connecting area has a smaller width than L is long. The width of the connection area is particularly preferably at most half, very particularly preferably at most a quarter, in particular at most one fifth of the length L. The width of the connection area is, within the meaning of the invention, the extension of the connection area parallel to the length of the pane in a plan view of the pane according to the invention first and / or the second contact area meant. In the context of the invention, the length of the first and the second contact area means the extension in the extension direction. By dividing the bridge into two contact areas and a narrower connection area, space can be saved on the pane and the material costs and material expenditure can be reduced.

The connection area preferably extends in a straight line from the first contact area to the second contact area of the electrically conductive bridge. A rectilinear connection between the contact areas is particularly advantageous, since a non-rectilinear design leads to a higher electrical resistance and thus power consumption.

In a further advantageous embodiment of the invention, the connection area is arranged outside the area between the first contact area and the second contact area. In this embodiment of the invention, the electrically conductive bridge preferably has a U or H shape. Because of the connection area, the is arranged outside the area between the first contact area and the second contact area, the area between the first and second heatable coating is not covered. As a result, greater transparency of the pane according to the invention can be retained in this area.

The number of electrically conductive bridges and electrically heatable coatings that are arranged in the sensor area can be freely determined. In this sense, the current path can run via the first heatable coating, the electrically conductive bridge, the second heatable coating and further electrically conductive bridges and heatable coatings between the first and the second bus bar.

In an advantageous embodiment of a pane according to the invention, the first pane has an electrically conductive heating layer surrounding the first and the second heatable coating. In particular when smaller areas, in this case the first and the second electrically heatable coating, are surrounded by an electrically conductive coating, it is important to keep the amount and number of busbars small. Busbars must be routed over the surrounding electrically conductive heating layer in an electrically insulated manner in order to be able to be connected to the first and the second electrically heatable coating. Materials and complex process steps for insulating the bus bars can therefore be reduced by the sensor area according to the invention.

In addition, the first and second heatable coatings are partially and preferably completely electrically or galvanically and/or materially separated from the surrounding coating by a coating-free separating line. The width of the dividing line is preferably from 30 μm to 200 μm and particularly preferably from 70 μm to 140 μm. The dividing line between the first and the second heatable coating can also be wider than in the other areas. The dividing line between the first and the second heatable coating particularly preferably has a width of 1 cm to 10 cm. Such a separating line allows the electrical structures within the sensor area to be isolated from a heating layer in the vicinity of the sensor area without short circuits.

The heating layer is preferably transparent and electrically conductive. It can be applied to part of the surface of the first pane. The heating layer can have an IR-reflecting effect. Notwithstanding an IR-reflecting effect of the heating layer, it can be galvanically separated from the first and second heating coating separated heating layer in the area can also be used to heat the rest of the pane.

For this purpose, preferably at least two outer busbars provided for connection to the voltage source or to a further voltage source are connected to the heating layer surrounding the sensor area in such a way that a current path for a heating current is formed between the outer busbars. The outer busbars are not electrically connected to the at least first, second, and optionally third busbars. The outer busbars are preferably arranged in the edge area along two opposite side edges of the heating layer.

For the purposes of the present invention, “transparent” means that the total transmission of the composite pane corresponds to the legal provisions for windshields and preferably has a transmittance of more than 50% and particularly preferably more than 60%, in particular more than 70%, for visible light . This means that layers of the laminate together meet the legal requirements for windshields. If a layer, for example the heating layer, is transparent, it has a light transmission which does not reduce the total transmission of the laminated pane to a level below the statutory provisions. This refers to the see-through area of the laminated pane. The laminated pane can have sections that are not transparent.

Correspondingly, "opaque" means a light transmission of less than 10%, preferably less than 5% and in particular 0%.

The width of the first and/or second bus bar and/or the electrically conductive bridge inside and possibly outside the sensor area is preferably from 2 mm to 30 mm, particularly preferably from 4 mm to 20 mm and in particular from 10 mm to 20 mm. Thinner busbars or electrically conductive bridges lead to an excessively high electrical resistance and thus to excessive heating of the busbar during operation. Furthermore, thinner busbars or bridges are difficult to fabricate using printing techniques such as screen printing. Thicker busbars or bridges require an undesirably high use of material. Furthermore, they lead to an excessive and unaesthetic restriction of the viewing area of the pane. The length of the bus bar or the electrically conductive bridge depends on the extent of the area to be heated. In the case of a bus bar which is in the form of a strip, the longer of its dimensions is called length and the shorter of its dimensions is called width.

If the heating layer is used for heating, typically the outer busbars are preferably arranged along a side edge on the heating layer and in particular run approximately parallel to one another. The length of the outer busbar is typically substantially equal to the length of the side edge of the heater layer, but may be slightly greater or lesser. More than two outer busbars can also be arranged on the heating layer, preferably in the edge area along two opposite side edges of the heating layer. More than two outer busbars can also be arranged on the heating layer, for example around two or more independent heating fields.

In an advantageous embodiment of the invention, the first and/or second busbar is applied to the surface of the first pane and/or the heating layer and/or the first and second heatable coating by means of soldering or gluing. The busbars applied in this way are preferably in the form of wire or strips of an electrically conductive film. The busbars then contain, for example, at least aluminum, copper, tinned copper, gold, silver, zinc, tungsten and/or tin or alloys thereof. The strip preferably has a thickness of 10 μm to 500 μm, particularly preferably 30 μm to 300 μm. Busbars made of electrically conductive foils with these thicknesses are technically easy to implement and have an advantageous current-carrying capacity. The strip can be electrically conductively connected to the electrically conductive structure, for example via a soldering compound, via an electrically conductive adhesive or by direct application.

Alternatively, the at least first and/or second busbar is designed as a printed and burned-in conductive structure. The printed busbars preferably contain at least one metal, a metal alloy, a metal compound and/or carbon, particularly preferably a noble metal and in particular silver. The printing paste preferably contains metallic particles, metal particles and/or carbon and, in particular, noble metal particles such as silver particles. The electrical conductivity is preferably achieved by the electrically conductive particles. The particles can be in an organic and/or inorganic matrix such as pastes or inks, preferably as a printing paste with glass frits. The layer thickness of the printed bus bars is preferably from 5 μm to 40 μm, particularly preferably from 8 μm to 20 μm and very particularly preferably from 8 μm to 12 μm. Printed busbars with these thicknesses are technically easy to implement and have an advantageous current-carrying capacity.

The specific resistance p _a of the at least first and/or second busbar is preferably from 0.8 pOhmvcm to 7.0 pOhmvcm and particularly preferably from 1.0 pOhmvcm to 2.5 pOhmvcm. Busbars with specific resistances in this range are technically easy to implement and have an advantageous current-carrying capacity.

Depending on the material of the heating layer and/or electrically heatable coating, it can be advantageous to protect the coatings with a protective layer, for example a paint, a polymer film and/or a second pane.

The first and second busbars may be in material contact with the surrounding heating layer. In this case, however, the first and second busbars are surrounded by an electrical insulating layer in the area of material contact with the heating layer, so that the busbars are not electrically connected to the heating layer. The insulating layer is preferably a polyimide-based polymeric coating.

In an advantageous embodiment of the invention, the electrically conductive bridge is designed as a metal foil or metal wire. The electrically conductive bridge can be applied to the surface of the first pane and/or to the first and second heatable coating by means of soldering or gluing. The electrically conductive bridge then contains, for example, at least aluminum, copper, tinned copper, gold, silver, zinc, tungsten and/or tin or alloys thereof. The strip preferably has a thickness of 5 μm to 400 μm, particularly preferably 40 μm to 250 μm. Electrically conductive bridges with these thicknesses are technically easy to implement and have an advantageous current-carrying capacity. The electrically conductive bridge can be electrically conductively connected to the electrically conductive structure (in this case the first and second heatable coating), for example via a solder mass, via an electrically conductive adhesive or by direct application.

Alternatively, the electrically conductive bridge is designed as a burned printing paste. The electrically conductive bridge can be printed in this way and preferably contains at least one metal, a metal alloy, a metal compound and/or carbon, particularly preferably a precious metal and in particular silver. The electrical conductivity is preferably achieved by the electrically conductive particles. The particles can be in an organic and/or inorganic matrix such as pastes or inks, preferably as a printing paste with glass frits. The layer thickness of the printed, electrically conductive bridge is preferably from 5 μm to 40 μm, particularly preferably from 8 μm to 20 μm and very particularly preferably from 8 μm to 12 μm. Printed, electrically conductive bridges with these thicknesses are technically easy to implement and have an advantageous current-carrying capacity.

The specific resistance p _a of the electrically conductive bridge is preferably from 0.8 pOhmvcm to 7.0 pOhmvcm and particularly preferably from 1.0 pOhmvcm to 2.5 pOhmvcm. Depending on the material of the heating layer and/or electrically heatable coating, it can be advantageous to protect the electrically conductive bridge with a protective layer, for example a lacquer, a polymer film and/or a second pane.

The first and second electrically heatable coating and heating layer are known, for example, from DE202008017611 U1, US2002/0045037 A1 or WO2012/052315 A1. They typically contain one or more, for example two, three or four, electrically conductive, functional layers. The functional layers preferably contain at least one metal, for example silver, gold, copper, nickel and/or chromium or a metal alloy. The functional layers particularly preferably contain at least 90% by weight of the metal, in particular at least 99.9% by weight of the metal. The functional layers can consist of the metal or the metal alloy. The functional layers particularly preferably contain silver or an alloy containing silver. Such functional layers have a particularly advantageous electrical conductivity combined with high transmission in the visible spectral range. The thickness of a functional layer is preferably from 5 nm to 50 nm, particularly preferably from 8 nm to 25 nm. In this thickness range of the functional layer, an advantageously high transmission in the visible spectral range and a particularly advantageous electrical conductivity are achieved. The first and the second electrically heatable coating preferably each extend over an area from 10 cm ² to 1000 cm ² , particularly preferably from 20 cm ² to 100 cm ² .

At least one dielectric layer is typically arranged in each case between two adjacent functional layers of the coating. A further dielectric layer is preferably arranged below the first and/or above the last functional layer. A dielectric layer contains at least a single layer of a dielectric material, for example containing a nitride such as silicon nitride or an oxide such as aluminum oxide. However, dielectric layers can also have several individual layers include, for example, individual layers of a dielectric material, smoothing layers, matching layers, blocking layers and/or antireflection layers. The thickness of a dielectric layer is, for example, from 10 nm to 200 nm.

This layer structure is generally obtained by a sequence of deposition operations carried out by a vacuum process such as magnetic field-assisted sputtering.

In principle, the first and second electrically heatable coating and the heating layer can be any coating that is to be electrically contacted and has sufficient transparency. The first and second electrically heatable coating and the heating layer are preferably transparent to electromagnetic radiation, particularly preferably to electromagnetic radiation with a wavelength of 300 nm to 1,300 nm and in particular to visible light.

In an advantageous embodiment, the first and second electrically heatable coating and/or the heating layer are a layer or a layer structure of several individual layers with a total thickness of less than or equal to 2 μm, particularly preferably less than or equal to 1 μm.

An advantageous electrically heatable coating and heating layer has a sheet resistance of 0.4 ohms/square to 10 ohms/square. In a particularly preferred embodiment, the first and second electrically heatable coatings have a surface resistance of 0.5 ohms/square to 1 ohms/square. Coatings with surface resistances of this type are particularly suitable for heating vehicle windows with typical on-board voltages of 12 V to 48 V or in electric vehicles with typical on-board voltages of up to 500 V.

The heating layer can extend over the entire surface of the first pane. Alternatively, however, the heating layer can also extend over only part of the surface of the first pane. The heating layer preferably extends over at least 50%, particularly preferably over at least 70% and very particularly preferably over at least 90% of the inside surface of the first pane. In addition to the coating-free zones, the heating layer can also have one or more coating-free areas. In an advantageous embodiment of the pane according to the invention, the surface of the first pane, on which the first and second electrically heatable coating are arranged, is connected over a surface area to a second pane via a thermoplastic intermediate layer.

In principle, all electrically insulating substrates that are thermally and chemically stable and dimensionally stable under the conditions of manufacture and use of the pane according to the invention are suitable as the first and optionally second pane.

Several panes are connected to one another by at least one thermoplastic intermediate layer. The intermediate layer preferably contains at least one thermoplastic, preferably polyvinyl butyral (PVB), ethylene vinyl acetate (EVA) and/or polyethylene terephthalate (PET). However, the thermoplastic intermediate layer can also, for example, be polyurethane (PU), polypropylene (PP), polyacrylate, polyethylene (PE), polycarbonate (PC), polymethyl methacrylate, polyvinyl chloride, polyacetate resin, casting resins, acrylates, fluorinated ethylene-propylene, polyvinyl fluoride and/or ethylene Tetrafluoroethylene, or copolymers or mixtures thereof. The thermoplastic intermediate layer can be formed by one or more thermoplastic films arranged one on top of the other, the thickness of a thermoplastic film preferably being from 0.25 mm to 1 mm, typically 0.38 mm or 0.76 mm.

In a laminated pane according to the invention consisting of a first pane, an intermediate layer and a second pane, the heating layer and/or the first and the second electrically heatable coating can be applied directly to the first pane or to a carrier film or to the intermediate layer itself. The first pane and the second pane each have an inside surface and an outside surface. The inside surfaces of the first and second panes face each other and are bonded together by the thermoplastic interlayer. The outside surfaces of the first and second discs face away from each other and from the thermoplastic intermediate layer. The first and second electrically heatable coatings are applied to the inside surface of the first pane. Of course, a further electrically heatable coating and/or a heating layer can also be applied to the inside surface of the second pane. The outside surfaces of the panes can also have coatings. The terms “first pane” and “second pane” are chosen to differentiate between the two panes in a composite pane according to the invention. With the terms is no statement about the connected geometric arrangement. If the pane according to the invention is intended, for example, to separate the interior from the outside environment in an opening, for example of a vehicle or a building, the first pane can face the interior or the outside environment.

In an advantageous embodiment of a pane according to the invention as a composite pane, the inside surface of the first pane has a peripheral edge area with a width of 2 mm to 50 mm, preferably 5 mm to 20 mm, which is not provided with the heating layer. The heating layer then has no contact with the atmosphere and is advantageously protected from damage and corrosion inside the pane by the thermoplastic intermediate layer.

The first and second electrically heatable coating and the heating layer can particularly preferably contain indium tin oxide (ITO), fluorine-doped tin oxide (SnO 2 :F) or aluminum-doped zinc oxide (ZnO:Al).

The first pane and, if present, the second pane preferably contain glass, particularly preferably flat glass, float glass, quartz glass, borosilicate glass, soda-lime glass, or clear plastics, preferably rigid clear plastics, in particular polyethylene, polypropylene, polycarbonate, polymethyl methacrylate, polystyrene, polyamide , polyester, polyvinyl chloride and/or mixtures thereof. The first pane and/or the second pane are preferably transparent, in particular for use of the pane as a windshield or rear pane of a vehicle or other uses where high light transmission is desired. However, for panes that are not in the driver's field of vision relevant to traffic, for example for roof panes, the transmission can also be much lower, for example greater than 5%.

The thickness of the pane can vary widely and can thus be perfectly adapted to the requirements of the individual case. Panes with standard thicknesses of 1.0 mm to 25 mm, preferably 1.4 mm to 2.5 mm for vehicle glass and preferably 4 mm to 25 mm for furniture, appliances and buildings, in particular for electric heaters, are preferably used. The size of the disc can vary widely and depends on the size of the use according to the invention. The first pane and optionally the second pane have areas of 200 cm ² up to 20 m ² , which are common in vehicle construction and architecture, for example. The disc can have any three-dimensional shape. Preferably, the three-dimensional shape has no shadow zones so that it can be coated by, for example, sputtering. Preferably, the first and/or second pane are planar or slightly or heavily curved in one or more directions of space. In particular, planar discs are used. The discs can be colorless or colored.

In an advantageous embodiment of the pane according to the invention, the first and/or second heatable coating has a rectangular shape in a plan view of the surface of the pane. The advantage of this configuration is that the busbars connected to the heatable coatings and the electrically conductive bridge can be applied along an edge area of the heatable coatings without complex process steps. As a result, the entire surface of the heatable coatings is heated to almost the same extent, which means that local heat maxima can be reduced.

The first and second busbars are electrically contacted by one or more connecting lines. The connection line is preferably designed as a flexible film conductor (flat conductor, ribbon conductor). This is understood to mean an electrical conductor whose width is significantly greater than its thickness. Such a foil conductor is, for example, a strip or band containing or consisting of copper, tinned copper, aluminum, silver, gold or alloys thereof. The foil conductor has, for example, a width of 2 mm to 16 mm and a thickness of 0.03 mm to 0.1 mm. The foil conductor can have an insulating, preferably polymeric, sheathing, for example based on polyimide. Foil conductors that are suitable for contacting electrically heatable coatings or heating layers in panes only have a total thickness of 0.3 mm, for example. Such thin foil conductors can be embedded without difficulty between the individual discs in the thermoplastic intermediate layer. A foil conductor strip can contain several conductive layers that are electrically isolated from one another.

Alternatively, thin metal wires can also be used as the electrical connection line. The metal wires contain in particular copper, tungsten, gold, silver or aluminum or alloys of at least two of these metals. The alloys can also contain molybdenum, rhenium, osmium, iridium, palladium or platinum.

In an advantageous embodiment of the invention, the at least one electrical connection line is connected to a contact strip, for example by means of a soldering compound or an electrically conductive adhesive. The contact strip is then connected to the first and/or second busbar. According to the invention, the contact strip is an extension of the connection line, so that the connecting surface between the contact strip and the busbar is to be understood as the contact surface from which the distance runs in the direction of extension of the busbar. The contact strip preferably contains at least one metal, particularly preferably copper, tinned copper, silver, gold, aluminum, zinc, tungsten and/or tin. This is particularly advantageous with regard to the electrical conductivity of the contact strip. The contact strip can also contain alloys, which preferably contain one or more of the elements mentioned and optionally other elements, for example brass or bronze.

The contact strip is preferably designed as a strip of a thin, electrically conductive film. The thickness of the contact strip is preferably from 10 μm to 500 μm, particularly preferably from 15 μm to 200 μm, very particularly preferably from 50 μm to 100 μm. Films with these thicknesses are technically easy to produce and readily available, and they also have an advantageously low electrical resistance.

The invention further includes a method for producing a pane according to the invention with an electrically heatable sensor area, at least comprising:

(a) Applying at least a first and a second electrically heatable coating to a portion of the surface of a first pane such that the first and second electrically heatable coatings are not in direct contact with each other.

(b) The application of a first and second busbar intended for connection to a voltage source, which are connected to the at least first and second electrically heatable coating in such a way that a current path for a heating current is formed between the first and second busbar. The at least first and second electrically heatable coating are electrically conductively connected to one another by means of at least one electrically conductive bridge. As a result, the current path runs via the at least first heatable coating, the at least one electrically conductive bridge and the at least second heatable coating.

The at least first and second electrically heatable coating can be applied in method step (a) by methods known per se, preferably by cathode sputtering supported by a magnetic field. This is particularly advantageous with regard to a simple, quick, inexpensive and uniform coating of the first pane. However, the electrically heatable coatings can also be produced, for example, by vapor deposition, chemical vapor deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD) or applied by wet-chemical methods.

The first pane can be subjected to a temperature treatment during or after method step (a). In this case, the first pane with the at least first and second electrically heatable coating is heated to a temperature of at least 200.degree. C., preferably at least 300.degree. The temperature treatment can serve to increase the transmission and/or to reduce the surface resistance of the first and second electrically heatable coating.

The first sheet can be bent after step (a), typically at a temperature of 500°C to 700°C. Since it is technically easier to coat a flat pane, this procedure is advantageous if the first pane is to be bent. Alternatively, the first pane can also be bent before or during method step (a), for example if the first and/or second electrically heatable coating is not suitable for surviving a bending process without being damaged.

The application of the first and/or second bus bar and/or the at least one electrically conductive bridge in method step (b) is preferably carried out by printing and baking an electrically conductive paste in a screen printing process or in an inkjet process. Alternatively, the first and/or second bus bar and/or the at least one electrically conductive bridge can be applied, preferably placed, soldered or glued onto the respective first and/or second electrically heatable coating as a strip of an electrically conductive film.

In the screen printing process, the lateral shape is created by masking the fabric through which the printing paste with the metal particles is pressed. By suitably shaping the masking, for example, the width of the bus bars or electrically conductive bridges can be predetermined and varied in a particularly simple manner.

An advantageous development of the method according to the invention comprises at least the following further steps:

(c) the planar arrangement of the coated surface of the first pane via a thermoplastic intermediate layer with a second pane to form a layer stack and

(d) the lamination of the stack of layers obtained to form a composite pane. The thermoplastic intermediate layer can be formed by a single thermoplastic foil or by two or more thermoplastic foils which are arranged one on top of the other in terms of surface area.

The lamination of the first and second panes in process step (d) preferably takes place under the action of heat, vacuum and/or pressure. Methods known per se can be used to produce a laminated pane.

For example, so-called autoclave processes can be carried out at an increased pressure of about 10 bar to 15 bar and temperatures of 130° C. to 145° C. for about 2 hours. Known vacuum bag or vacuum ring methods work, for example, at about 200 mbar and 80°C to 110°C. The first pane, the thermoplastic intermediate layer and the second pane can also be pressed in a calender between at least one pair of rollers to form a composite pane. Plants of this type are known for the production of discs and normally have at least one heating tunnel in front of a pressing plant. The temperature during the pressing process is, for example, from 40°C to 150°C. Combinations of calender and autoclave processes have proven particularly useful in practice. Alternatively, vacuum laminators can be used. These consist of one or more chambers that can be heated and evacuated, in which the first pane and the second pane are laminated within about 60 minutes, for example, at reduced pressures of 0.01 mbar to 800 mbar and temperatures of 80 °C to 170 °C.

The invention also includes the use of the pane according to the invention with electrical contacting in buildings, in particular in the entrance area, window area, roof area or facade area, as a built-in part in furniture and appliances, in means of transport for traffic on land, in the air or on water, in trains , ships and in particular motor vehicles, for example as a windshield, rear window, side window and/or roof window. The use includes optical sensors and camera systems, in particular for vision-based driver assistance systems, ADAS or Advanced Driver Assistance Systems, ADAS, whose beam path runs through the sensor area.

The invention is explained in more detail below using exemplary embodiments, reference being made to the attached figures. They show in a simplified representation that is not true to scale: FIG. 1A shows a plan view of an embodiment of the pane according to the invention with an electrically heatable sensor area,

FIG. 1B shows an enlarged representation of an embodiment of an electrically conductive bridge,

FIG. 1C shows an enlarged view of the sensor area from FIG. 1A,

Figure 1D is a cross-sectional view taken along section line AA' through the disc as shown in Figures 1A and 1A

FIGS. 2-4 different, enlarged configurations of the sensor area of the pane according to the invention.

FIG. 1A shows a plan view of an exemplary embodiment of a pane 100 according to the invention with an electrically heatable sensor area 3. FIG. FIG. 1C shows an enlarged representation of the sensor area 3 from FIG. 1A and FIG. 1C shows a cross section through the pane 100 according to the invention from FIG. 1A along the section line AA′.

As shown in FIG. 1A, the pane 100 according to the invention comprises, among other things, a heating layer 6 which is applied to the first pane 1. FIG. The heating layer 6 is a layer system which contains, for example, three electrically conductive silver layers which are separated from one another by dielectric layers. The heating layer 6 conducts electricity and is transparent. If a current flows through the heating layer 6, it is heated as a result of its electrical resistance and Joule heat generation. The heating layer 6 can be supplied with electricity, for example, via two or more busbars, which are applied in the edge area on the upper and lower edge or the side edges on the outer surface III of the first pane 1 and are in material and electrical contact with the heating layer 6 (not here). shown).

As shown in FIG. 1A, the heating layer 6 extends, for example, over the entire outer surface III of the first pane 1 minus the sensor area 3, and a frame-shaped and uncoated area surrounding the first pane 1 with a width of, for example, 8 mm. The uncoated area is used for electrical insulation between the heating layer 6 and the vehicle body. The uncoated area is hermetically sealed by gluing to the thermoplastic intermediate layer 13 in order to protect the sensor area 3 and the heating layer 6 from damage and corrosion.

Figure 1C shows an enlarged sensor area 3 in a plan view of the outside III of the windshield 100. The sensor area 3 is surrounded by a coating-free dividing line 11, which materially and galvanically (i.e for direct currents) separates from the surrounding heating layer 6. The dividing line 10 has a width of 100 μm, for example, in which the heating layer 6 has been completely removed. The dividing line 10 is produced, for example, by laser structuring (laser ablation).

The first and second heatable coating 9.1, 9.2 are arranged within the sensor area 3 and each consist, for example, of a PET film that is coated with one or more silver layers. The first and second heatable coating 9.1, 9.2 are not in physical contact with one another, but are separated by an uncoated area. They are arranged side by side in plan view of the pane 100 from the left side edge of the pane 100 to the right side edge of the pane 100 . As shown in FIG. 4, an arrangement from the top edge of pane 100 to the bottom edge of pane 100, ie from top to bottom, is also possible. The silver layer has a thickness of 300 nm, for example, and the PET film has a thickness of 0.1 mm, for example. The heatable coatings 9.1, 9.2 are arranged on the first pane 1. The first and second heatable coating 9.1, 9.2 are suitable for ensuring that an optical sensor 11 can see through. For this reason, two sensor windows 2.1, 2.2, ie the areas of pane 100 through which an optical sensor 11 can detect an optical beam path, are arranged completely inside the heatable coatings 9.1, 9.2. One sensor window 2.1 is arranged within the first heatable coating 9.1 and the other sensor window 2.2 is arranged within the second heatable coating 9.2. Due to this arrangement, the attachment of up to two optical sensors 11 is possible. One of the sensors 11 is shown schematically in cross section in FIG. 1D.

For electrical contacting, a left first bus bar 8.1 is arranged on the left edge area of the first heatable coating 9.1 and a right second bus bar 8.2 on the right edge area of the second heatable coating 9.2 on the heatable coatings 9.1, 9.2. These outer bus bars are 8.1, 8.2 separated by a total distance M in the area of the heatable coatings 9.1, 9.2. In addition, a central, electrically conductive bridge 7 is arranged between the first and second busbars 8.1, 8.2 and between the first and second heatable coating 9.1, 9.2. The bridge 7 includes a first and a second contact area 7.1, 7.2 and a connection area 7.3. For the sake of simplicity, the first contact area 7.1 is also referred to below as the left contact area and the second contact area 7.2 is referred to as the right contact area. The electrically conductive bridge 7 overlaps with the left contact area 7.1 on the right edge area of the first heatable coating 9.1 and with the right contact area 7.2 on the left edge area of the second heatable coating 9.2 and is in direct spatial contact with the first and the second heatable coating 9.1, 9.2 arranged. The left contact area 7.1 extends, for example, with a length L of 10 cm over the right edge area of the first heatable coating 9.1. The right-hand contact area 7.2 extends, for example, with a length L of 10 cm over the left-hand edge area of the second heatable coating 9.2.

The first bus bar 8.1 is at a distance B.1 from the left contact area 7.1 of the electrically conductive bridge 7. The second bus bar 8.2 is at a distance B.2 from the right-hand contact area 7.2 of the electrically conductive bridge 7. The connecting area 7.3 materially and electrically connects the left contact area 7.1 to the right contact area 7.2, so that a heating current flows via a current path 14 from the first busbar 8.1 via the first heatable coating 9.1, via the electrically conductive bridge 7 and via the second heatable coating 9.2 to the second Busbar 8.2 can flow. The connection area 7.3 of the electrically conductive bridge 7 is connected to the left and right contact areas 7.1, 7.2 at the upper ends of the contact areas, so that a plan view of the sensor area 3 results in a shape similar to the Greek letter “GT”. However, the design of the bridge 7 can also be completely different, as indicated in FIGS. 2 and 4, for example. It goes without saying that the electrically conductive bridge 7 can also assume completely different forms. For example, the connection area 7.3 of the electrically conductive bridge 7 can also connect the lower ends of the left and right contact areas 7.1, 7.2 with one another, so that a shape similar to the letter "U" is created when the sensor area 3 is viewed from above, or the connection area 7.3 connects the upper end of the left contact area 7.1 with the lower end of the right contact area 7.2, so that a plan view of the sensor area 3 creates a shape similar to the letter "N". Of course, the shape of the electrically conductive bridge 7 as a mirror-inverted “N” is also possible. Because of the arrangement of the busbars 8.1, 8.2, the total distance M is greater than the total individual distances B.1, B.2. The bus bars 8.1, 8.2 and the electrically conductive bridge 7 contain silver particles, for example, and were applied using the screen printing process and then burned in. The first and second heatable coatings

9.1. For example, 9.2 have a resistance of 1.0 ohms/square. In the example shown, the first and second busbars 8.1, 8.2 have a constant thickness of, for example, approximately 10 μm and a constant specific resistance of, for example, 2.3 pOhmvcm. The first and second bus bars 8.1, 8.2 shown in FIG. 1C can have physical contact with the heating layer 6 surrounding the sensor region 3. In this case, however, the busbars 8.1, 8.2 are surrounded by an electrical insulating layer in the area of material contact with the heating layer 6, so that the busbars 8.1, 8.2 are not electrically connected to the heating layer 6. The insulating layer is, for example, a polyimide-based polymeric coating.

By using the electrically conductive bridge 7 between the first and second heatable coating 9.1, 9.2, the total resistance between the first and second bus bar 8.1, 8.2 can be reduced compared to a first or second heatable coating which is between the first bus bar 8.1 and the second bus bar

8.2 is arranged and has a length equal to the total distance M can be reduced. Because of the lower overall resistance, the electrical voltage applied across the first and second bus bars 8.1, 8.2 can be reduced for the same electrical power, or the electrical power can be increased for the same electrical voltage.

Such an arrangement of heatable coatings 9.1, 9.2, busbars 8.1, 8.2 and electrically conductive bridge 7 enables the heating of the first and second sensor window 2.1, 2.2 with only a first and a second busbar 8.1, 8.2. In comparison to a generic solution in which the first and second sensor windows 2.1, 2.2 are each heated separately, this arrangement avoids further material costs and the increased space requirement on pane 100 for, for example, a third and fourth busbar.

Both the first and the second busbar 8.1, 8.2 lead to a connection area, which is provided with a connection line 4.1, 4.2, which connects the busbars 8.1, 8.2 to a voltage source 5. The connection lines 4.1. 4.2, can as at well-known foil conductors can be formed, which are electrically conductively connected to the first and second busbars 8.1, 8.2 via a contact surface, for example by means of a soldering compound, an electrically conductive adhesive or by simply lying and pressing inside the pane 100. The foil conductor contains, for example, a tinned Copper foil with a width of 10 mm and a thickness of 0.3 mm. The foil conductors can merge into connecting cables that are connected to the voltage source 5 . The voltage source 5 provides, for example, an on-board voltage that is customary for motor vehicles, preferably from 12 V to 15 V and, for example, about 14 V. Alternatively, the 14 V voltage source can also have higher voltages, for example from 35 V to 45 V and in particular 42 V.

As is usual in glazing technology, the first and second bus bars 8.1, 8.2, the electrically conductive bridge 7 and the connections and the connection lines 4.1, 4.2 can be covered by opaque layers of paint known per se as a cover print (not shown here).

As shown in FIG. 1D, the pane 100 according to the invention comprises a first pane 1 and a second pane 12, which are connected to one another via a thermoplastic intermediate layer 13. The pane 100 is, for example, a vehicle pane and in particular the windshield of a passenger car, which has an upper edge and an opposite lower edge as well as two shorter side edges. The first pane 1 is provided, for example, to face the interior in the installed position. The first pane 1 and the second pane 12 are made of soda-lime glass. The thickness of the first pane 1 is 1.6 mm, for example, and the thickness of the second pane 12 is 2.1 mm. The thermoplastic intermediate layer 13 contains, for example, mostly polyvinyl butyral (PVB) and has a thickness of 0.76 mm. The second pane 12 has an outer surface I facing the external environment and an inner surface II facing the interior. The first pane 1 has an outer surface III facing the external environment and an inner surface IV facing the interior.

The variant shown in FIG. 2 essentially corresponds to the variant from FIG. 1C, so that only the differences are discussed here and otherwise reference is made to the description of FIG. 1C. The electrically conductive bridge 7 comprises a left and a right contact area 7.1, 7.2 and a connection area 7.3. The left and right contact areas 7.1, 7.2 are connected to the first and second heatable coating 9.1, 9.2 in the same way as shown in FIG Connection area 7.3 arranged centrally and transversely between the left and right contact areas 7.1, 7.2 arranged parallel to one another. The connection area 7.3 of the electrically conductive bridge 7 is materially and electrically conductively connected to the first and second contact area 7.1, 7.2. In a plan view of the sensor area 3, the shape of the electrically conductive bridge 7 resembles the letter “H”.

The variant shown in FIG. 3 essentially corresponds to the variant from FIG. 1C, so that only the differences are discussed here and otherwise reference is made to the description of FIG. 1C. The first and second heatable coatings 9.1, 9.2 are not arranged from left to right along the top and bottom edge of pane 100, as shown in FIG. 1C, but from bottom to top along the side edges. The first and second bus bars 8.1, 8.2 are accordingly not arranged along the left and right edge areas of the heatable coatings 9.1, 9.2, but rather along the lower and upper edge areas. The electrically conductive bridge 7 is arranged accordingly between the first and second heatable coating 9.1, 9.2, with the left contact area 7.1 now being in material contact with the upper edge area of the first heatable coating 9.1 and the right contact area 7.2 with the lower edge area of the second heatable coating 9.2 and is electrically conductive contact.

The variant of the electrically heatable sensor area 3 shown in FIG. 4 represents an expansion of the arrangement shown in FIG. 1C. The sensor area 3 has been expanded to include a further heatable coating 9.3 and a further electrically conductive bridge 7, which is designed in the form of the bridge shown in FIG. 1B. In this way, another individually heatable sensor window 2.3 is arranged. It is thus shown that according to the desired number of sensors further heatable coatings 9.1, 9.2, 9.3 with sensor windows 2.1, 2.2, 2.3 and electrically conductive bridges 7 can be arranged next to one another and between two busbars 8.1, 8.2. It goes without saying that the shape of the electrically conductive bridges 7 is not limited to the shapes shown in FIG. reference list

1 first disc

2.1, 2.2, 2.3 Sensor window 3 Electrically heatable sensor area

4.1, 4.2 Connection lines

5 voltage source

6 heating layer 7 electrically conductive bridge

7.1 first contact area

7.2 second contact area

7.3 connection area 8.1 first busbar 8.2 second busbar

9.1 first electrically heatable coating

9.2 second electrically heatable coating

9.3 additional electrically heatable coating 10 dividing line 11 sensor 12 second pane

13 thermoplastic intermediate layer

14 current path

B.1, B.2 distance

M total distance

I outer surface of the second disc 13

II inner surface of the second disc 13

III Outer surface of the first disc 1

IV inner surface of the first disc 1

A-A' cutting line

100 disc

Claims

patent claims

1. Pane (100) with an electrically heatable sensor area (3), at least comprising: a first pane (1) with a surface (III), at least a first and a second electrically heatable coating (9.1, 9.2), each on a part are applied to the surface (III) and have no direct contact with each other, a first and a second bus bar (8.1, 8.2) provided for connection to a voltage source (5), which are provided with the at least first and second electrically heatable coating (9.1, 9.2 ) are connected in that a current path (14) for a heating current is formed between the first and second busbars (8.1, 8.2), an electrically conductive heating layer (6) surrounding the first and second heatable coating (9.1, 9.2), the at least first and second electrically heatable coating (9.1, 9.2) are electrically conductively connected to one another by means of at least one electrically conductive bridge (7) and the current path (14) mi runs at least over the first heatable coating (9.1), the electrically conductive bridge (7) and the second heatable coating (9.2), the first and the second heatable coating (9.1, 9.2) each being completely separated by a coating-free dividing line (10) from the surrounding heating layer (6) are galvanically and materially separated.

2. Pane (100) according to claim 1, wherein the electrically conductive bridge (7) comprises a first contact area (7.1), a second contact area (7.2) and a connecting area (7.3), the first contact area (7.1) having the first heatable Coating (9.1) and the second contact area (7.2) is connected to the second heatable coating (9.2) and the connecting area (7.3) spatially directly connects the first contact area (7.1) to the second contact area (7.2).

3. Disc (100) according to claim 2, wherein the connection area (7.3) outside the area between the first contact area (7.1) and the second Contact area (7.2) is arranged and the electrically conductive bridge (7) preferably has a U-shape.

4. Pane (100) according to one of claims 1 to 3, wherein the width of the coating-free parting line (10) is preferably from 30 μm to 200 μm and particularly preferably from 70 μm to 140 μm.

5. Pane (100) according to one of claims 1 to 4, wherein the first and/or second busbar (8.1, 8.2) are designed as a metal foil and in particular contain copper with a tin layer and preferably _a specific resistance pa of 0.8 pOhmvcm to 7.0 pOhnvcm and particularly preferably from 1.0 pOhnvcm to 2.5 pOhnvcm.

6. Pane (100) according to any one of claims 1 to 4, wherein the first and / or second busbar (8.1, 8.2) are designed as a burnt printing paste, which preferably contain metallic particles, metal particles and / or carbon particles and in particular silver particles and preferably one specific resistance pa from 0.8 pOhmvcm to 7.0 _pOhmvcm and particularly preferably from 1.0 pOhmvcm to 2.5 pOhmvcm.

7. Pane (100) according to one of claims 1 to 6, wherein the electrically conductive bridge (7) is designed as a metal foil, which in particular contains copper with a layer of tin or is designed as a fired printing paste, which preferably contains metallic particles, metal particles and/or Contains carbon particles and in particular silver particles.

8. Pane (100) according to one of claims 1 to 7, wherein the first and/or second electrically heatable coating (9.1, 9.2) has a surface resistance of 0.4 ohms/square to 10 ohms/square and preferably 0.5 ohms /square to 1 ohm/square.

9. Pane (100) according to one of claims 1 to 8, wherein the surface (III) of the first pane (1) is connected over a surface area to a second pane (12) via a thermoplastic intermediate layer (13).

10. Disc (100) according to any one of claims 2 to 9, wherein the first contact area (7.1) extends over an edge area of the first electrically heatable coating (9.1) and the second contact area (7.2) extends over an edge area of the second electrically heatable coating (9.2) with a length L.

11. Disc (100) according to claim 10, wherein the width of the connecting area (7.3) is smaller than the length L.

12. Disc (100) according to claim 10 or 11, wherein the connecting area (7.3) preferably extends in a straight line from the first contact area (7.1) to the second contact area (7.2).

13. A method for producing a pane (100) with an electrically heatable sensor area (3) according to any one of claims 1 to 12, at least comprising:

(a) Application of at least a first and a second electrically heatable coating (9.1, 9.2) on part of the surface (III) of a first pane (1), so that the first and second electrically heatable coating (9.1, 9.2) are not in direct contact have with each other

(b) Application of a first and second bus bar (8.1, 8.2) intended for connection to a voltage source (5), which are connected to the at least first and second electrically heatable coating (9.1, 9.2) in such a way that between the first and second busbar (8.1, 8.2) a current path (14) for a heating current is formed, wherein the at least first and second electrically heatable coating (9.1, 9.2) are also connected to one another in an electrically conductive manner by means of at least one electrically conductive bridge (7), so that the Current path (14) runs via the first and second heatable coating (9.1, 9.2) and the at least one electrically conductive bridge (7).

14. A method for producing a disk (100) according to claim 13, wherein subsequently

(c) the coated surface (III) of the first pane (1) is arranged flatly via a thermoplastic intermediate layer (13) with a second pane (12) to form a layer stack, and

(d) the stack of layers obtained is laminated to form a composite pane.

15. Use of the disc (100) according to one of claims 1 to 12 in means of locomotion for traffic on land, in the air or on water, in particular in motor vehicles, for example as a windscreen, Rear window, side windows and/or roof window, in particular for vision-based driver assistance systems (FAS) or Advanced Driver Assistance Systems (ADAS) whose beam path runs through the sensor area (3).