CN115119542A

CN115119542A - Glazing with electric heating field

Info

Publication number: CN115119542A
Application number: CN202280001178.0A
Authority: CN
Inventors: B·普罗科普
Original assignee: Saint Gobain Glass France SAS
Current assignee: Saint Gobain Glass France SAS
Priority date: 2021-01-18
Filing date: 2022-01-17
Publication date: 2022-09-27
Also published as: WO2022152910A1; EP4278861A1

Abstract

The invention relates to a glazing (1) having an electrical heating field (H1, H2), comprising: -at least one pane (2, 3), -a first collecting conductor (5) and a second collecting conductor (6) provided for connection to a voltage source, which are connected to one another by means of a heating wire (7) such that an electrical heating field (H1, H2) is formed between the two collecting conductors (5, 6), -at least one filament-free region (8) outside the heating field (H1, H2), wherein the first collecting conductor section (5.1) of the first collecting conductor (5) is guided around the filament-free region (8) in the following manner: such that the shortest distance between the first and second concentrating conductor segments (5.1, 6) is smaller than the shortest distance between the at least one second concentrating conductor segment (5.2) of the first concentrating conductor (5) and the second concentrating conductor (6), the first heating wire (7.1) extending from the first concentrating conductor segment (5.1) to the second concentrating conductor (6) in the first heating field region (H1), and the second heating wire (7.2) extending from the at least one second concentrating conductor segment (5.2) to the second concentrating conductor (6) in the second heating field region (H2), wherein the heating wire (7.1, 7.2) has the following characteristics i), ii) and/or iii): i) the electrical resistance of the first heating wire (7.1) is greater than the electrical resistance of the second heating wire (7.2), ii) the distance between directly adjacent first heating wires (7.1) is greater than the distance between directly adjacent second heating wires (7.2), iii) the waviness of the first heating wire (7.1) is greater than the waviness of the second heating wire (7.2), wherein the features i), ii) and/or ii) are configured such that the heating power per unit area in the first heating field region (H1) corresponds to the heating power per unit area in the at least one second heating field region (H2).

Description

Glazing with electric heating field

Technical Field

The present invention belongs to the technical field of glazing (glazing) manufacture and relates to glazing with an electrical heating field, a method for its manufacture and its use.

Background

The field of view of the vehicle window (especially the windshield) must be kept ice-free and fog-free. For example, in a motor vehicle equipped with an internal combustion engine, an air flow heated by engine heat may be directed onto the windows of the vehicle.

Furthermore, the pane (pane) can have an electrical heating function, whereby a heating field is formed by the electrically heatable structure. For example, composite glazings are known having a transparent conductive coating on the inner surface of one of the individual glazings. An external voltage source may be used to conduct current through the electrically conductive cladding, heating the cladding, and thus the glazing. WO2012/052315 a1 discloses, for example, such a heatable metal-based coating. It is also known to use electrically heatable wires, which are typically embedded in a thermoplastic interlayer in a composite glazing.

The electrical contacting of the electrically heatable structures is usually carried out by collecting conductors (busbars), as is known, for example, from US 2007/0020465 a 1. For example, the aggregate conductor is composed of a printed and baked silver paste. The focus conductors typically extend along the top and bottom edges of the windowpane. The collecting conductor collects the current flowing through the electrically heatable structure and conducts it to an external lead connected to a voltage source.

The screening of electromagnetic radiation by a pane with an electrically heatable structure is relatively strong, so that radio data communication can be significantly impaired, in particular in motor vehicles with an electrically heatable windshield. Thus, electrically heatable windshields are typically provided with areas ("communication windows") in which electrically heatable structures are not formed. These communication windows penetrate well at least for some ranges of the electromagnetic spectrum and thus enable a smooth data flow through the window glass. Communication windows, in which electronic devices such as sensors, cameras, etc. may be placed, are usually arranged near the upper edge of the window pane, where they may be well hidden by the upper screening strip.

However, due to the spatial extension of the communication window, the communication window may influence the heating characteristics of the electrically heatable structure, which at least locally influences the heating power per unit area. In fact, the communication window may result in a highly non-uniform heating power distribution, and the heating power below and near the communication window may vary significantly. As a result, very different pane temperatures may occur, causing significant thermal stress to the pane. In addition, the adhesive dots of the additional parts may be detached accordingly.

In general, it would be desirable to have a heatable glazing having an electrical heating field that has an at least substantially uniform heat output (heating power) per unit area throughout the heating field.

DE 112018004604T 5 discloses a glazing according to the preamble of claim 1. JP H0872674A discloses a window pane with heating wires of variable diameter and/or spacing.

In contrast, the object of the present invention is to provide an improved glazing with an electrical heating field, with which these disadvantages can be avoided. The glazing should be easy and inexpensive to manufacture in an industrial series.

Disclosure of Invention

According to the present proposal, these and other objects are solved by a glazing with an electrical heating field according to the independent claims. Advantageous embodiments of the invention result from the dependent claims.

According to the present invention, an electrically heatable glazing with an electrical heating field is shown, which is typically, but not necessarily, used to separate an interior environment from an exterior environment.

The glazing according to the invention can in principle take any design, in particular as a hollow glazing in which at least two panes are separated by at least one spacer, as a heat-strengthened single-pane safety glass, or as a laminated pane. Preferably, the glazing according to the invention is designed as a laminated glazing and comprises a first glazing having an outer side and an inner side and a second glazing having an inner side and an outer side, which are firmly bonded to one another by at least one thermoplastic interlayer (adhesive layer). The first pane may also be referred to as the outer pane and the second pane may be referred to as the inner pane. The surfaces or sides (sides) of two individual panes are usually referred to from the outside inwards as side I, side II, side III and side IV.

The glazing according to the invention comprises at least one pane and a first and a second collecting conductor which are provided for connection to a voltage source and are interconnected by means of a plurality of heating wires in such a way that an electrical heating field is formed between the first and the second collecting conductor.

The heating wire is arranged on the at least one pane, in particular on a surface of the at least one pane. The heating wires each extend from the first collecting conductor to the second collecting conductor and are preferably directly connected to both collecting conductors, so that a heating field is formed by the heating wires.

In the glazing according to the invention, at least one hot-wire-free region is provided outside the heating field, which region can be used, in particular, as a communication window. Advantageously, the hot-wire-free region is arranged at the upper edge of the glazing, in particular at least approximately in the centre of the pane. One or more sensors may be arranged at the hot-wire-free region, for example in the interior of the vehicle. The non-hot wire areas are free of any heating wires, which negatively influence the passage of electromagnetic radiation through the areas and thus the functioning of the sensor. The electroless filament area may have any suitable geometry, preferably the shape of the electroless filament area is rectangular or trapezoidal. Alternatively, an oval, circular, polygonal, or any other suitable shape may be selected for the non-heating wire regions.

According to the invention, the first collector conductor section of the first collector conductor is guided around the hot-wire-free region in the following manner: such that the shortest distance between the first aggregation conductor segment and the second aggregation conductor is smaller than the shortest distance between the at least one second aggregation conductor segment of the first aggregation conductor and the second aggregation conductor. Typically, at least one second aggregated-conductor segment is arranged adjacent to a first aggregated-conductor segment, wherein a second aggregated-conductor segment may be arranged adjacent to each side of a first aggregated-conductor segment, in which case the first aggregated conductor consists of a first aggregated-conductor segment and two second aggregated-conductor segments adjacent thereto.

The first heating wire extends from the first aggregate conductor segment to the second aggregate conductor such that the first heating wire forms a first heating field region. The second heating wire extends from at least one second concentrated conductor segment, in particular from two second concentrated conductor segments, to the second concentrated conductor, so that the second heating wire forms at least one second heating field region, in particular two second heating field regions. The heating wire is thus divided or composed of a first heating wire and a second heating wire. The first heating wire is spatially separated from the second heating wire. Accordingly, the heating field is divided into or consists of a first heating field region (defined by the first heating wire) and at least one second heating field region (defined by the second heating wire), in particular two second heating field regions. At least one second heating field region, in particular two second heating field regions, is spatially separated from the first heating field region.

According to the present invention, the first heating wire in the first heating field region and the second heating wire in the at least one second heating field region are formed in different manners from each other. More specifically, the first heating wire has a different waviness than the second heating wire, wherein the waviness of the first heating wire in the first heating field region is greater than the waviness of the second heating wire in the at least one second heating field region.

It is essential here that the waviness of the heating wires is designed such that the heating power per unit area (pane area) in the first heating field region corresponds to the heating power per unit area (pane area) in the at least one second heating field region.

The present invention is based on the insight that: due to the shorter distance between the two collecting conductors in the section of the first collecting conductor which runs around the hot wire-free region, the heating power per area is increased compared to the rest of the heating field, since the length of the otherwise identically formed heating wire is reduced and thus the length-dependent resistance of the heating wire (resistance per length, measured in ohms/meter) is reduced. This results in an undesirable non-uniform heating power per unit area in the entire heating field. According to the invention, by varying the waviness of the heating wires, a homogenization of the heating power per unit area can be achieved in an advantageous manner in the entire heating field. In this way, the disadvantages mentioned at the outset can be avoided, in particular, as a result of which no large thermal stresses occur on the window pane. Therefore, the hot-wire-free region can be appropriately formed in size, shape, and position according to its function, for example, as a communication window, without considering any thermal unevenness. These are the main advantages of the present invention.

In the glazing according to the invention, the heating field is formed by a heating wire extending between a first collecting conductor and a second collecting conductor, the two collecting conductors being electrically connected by the heating wire. The heating field is thus divided into a first heating field region and at least one second heating field region, in particular two second heating field regions.

According to the invention, the heating wires in the heating field are formed such that the waviness of the first heating wire in the first heating field region is greater than the waviness of the second heating wire in the at least one second heating field region.

In the sense of the present invention, a heating wire may be considered "corrugated", i.e. having a waviness, if it has a wavy, in particular meandering (e.g. sinusoidal) course along its extension. Basically, the corrugated heating wire extends in a (e.g. linear) extending direction and exhibits a corrugated meandering perpendicular to the extending direction. The length of the corrugated heating wire measured along its extension direction (without taking into account the corrugated meandering) is inevitably shorter than the actual length of the heating wire when the meandering is taken into account.

By stretching the corrugated heating wire into a straight shape, the waviness of the heating wire can be determined in a simple manner, whereby the waviness can be described by a relative value given by the length of the stretched (previously corrugated) heating wire and the length of the (unstretched) corrugated heating wire in its direction of extension without taking into account the corrugation meandering. It will be appreciated that in order to determine the waviness of the heating wire, the same heating wire needs to be considered. For example, if the length of the corrugated heating wire is extended by 10% by stretching the corrugated heating wire into a straight shape, the obtained relative value is 1.1 (length of the straight heating wire after stretching/length of the corrugated heating wire in the stretching direction before stretching).

The heating wires used in the glazing according to the invention are provided with corrugations, i.e. they have a wavy course which differs from a linear course. The waviness of the heating wire changes its length and thus also the length-dependent resistance of the heating wire (measured in ohms/meter).

In principle, changing the length of the heating wire changes the length-dependent resistance, which increases with increasing length. Due to the greater waviness of the first heating wire, the heating power per unit area in the first heating field region can be reduced in an advantageous manner compared to the heating power per unit area in the at least one second heating field region.

According to one embodiment of the glazing according to the invention, the first heating wires are provided with such a waviness that the length of each first heating wire increases to 1.1 to 1.4 times due to stretching. This measure enables a good homogenization of the heating power per unit area, in particular in the case of conventional vehicle glazing, such as windshields which are arranged at the upper edge of the pane without a hot-wire region.

According to other embodiments of the invention, at least one of the following features i) and ii) is implemented:

characteristic i):

the resistance of the first heating wire in the first heating field region is greater than the resistance of the second heating wire in the at least one second heating field region.

Characteristic ii):

the distance between directly adjacent first heating filaments in the first heating field region is larger than the distance between directly adjacent second heating filaments in the at least one second heating field region.

It is essential here that the features i) and/or ii) are designed such that the heating power per unit area (pane area) in the first heating field region corresponds to the heating power per unit area (pane area) in the at least one second heating field region.

According to feature i), the heating wires in the heating field are designed such that the electrical resistance of a first heating wire in a first heating field region is greater than the electrical resistance of a second heating wire in at least one second heating field region. Due to the higher electrical resistance of the first heating wire, the heating power per area in the first heating field region can be reduced in an advantageous manner compared to the heating power per area in the at least one second heating field region.

In principle, the increase in resistance may be achieved in any way, for example by selecting a different material for the first heating wire than for the second heating wire having a higher resistance. According to an advantageous embodiment of the glazing according to the invention, the heating wires are of the same material and the diameter of the first heating wire in the first heating field region is smaller than the diameter of the second heating wire in the at least one second heating field region. By this measure, the resistance of the heating wire can be selectively adjusted in a simple manner by dimensioning the diameter of the heating wire such that its resistance increases and the heating power per unit area decreases with increasing diameter of the heating wire and vice versa.

Preferably, the diameter of the first heating wire in the first heating field region is 20% to 30%, in particular 25%, smaller than the diameter of the second heating wire in the at least one second heating field region, as a result of which a good homogenization of the heating power per unit area can be achieved, in particular in the case of conventional vehicle glazings, such as windscreens, in which no heating wire region is arranged at the upper edge of the pane.

Advantageously, the diameter of the heating wire is from 10 μm to 200 μm, in particular from 15 μm to 35 μm, especially from 18 μm to 29 μm.

According to feature ii), the heating filaments in the heating field are formed such that the distance between directly adjacent first heating filaments in the first heating field region is larger than the distance between directly adjacent second heating filaments in the at least one second heating field region. Due to the large distance between the first heating wires, the heating power per area in the first heating field region can be reduced in an advantageous manner compared to the heating power per area in the at least one second heating field region.

According to an embodiment of the glazing according to the invention, the distance between directly adjacent first heating wires in the first heating field region is 20% to 30%, in particular 25%, greater than the distance between directly adjacent second heating wires in the second heating field region. This measure enables a good homogenization of the heating power per unit area, in particular in the case of conventional vehicle glazing, such as windshields which are arranged at the upper edge of the pane without a hot-wire region.

Advantageously, the distance between directly adjacent heating wires in the heating field is in the range of 2 to 3 mm.

According to another embodiment of the glazing according to the invention, the length dependent resistance of the heating wire is in the range of 100 to 220 ohm/meter.

According to another embodiment of the glazing according to the invention, the heating wires in the heating field have a length in the range of 50 to 200cm, depending on the height of the glazing.

The heating wire may be electrically heated and, for this purpose, is composed of an electrically conductive material which is substantially selectable as required. Advantageously, the heating wire is made of a metallic material. Preferably, the heating wire comprises or consists of aluminium, copper, tin-plated copper, gold, silver, zinc, tungsten and/or tin or alloys thereof, in particular copper and/or tungsten. The first heating wire may be composed of the same or different material as that of the second heating wire.

The at least one pane preferably comprises or consists of glass, particularly preferably flat glass, float glass, quartz glass, borosilicate glass, soda-lime glass, or a transparent plastic, preferably a rigid transparent plastic, in particular polyethylene, polypropylene, polycarbonate, polymethyl methacrylate, polystyrene, polyamide, polyester, polyvinyl chloride and/or mixtures thereof. Suitable glasses are known, for example, from EP 0847965B 1.

The thickness of the at least one pane can vary widely and can be adapted to the requirements of different situations. Preferably, 1.0mm to 25mm standard thickness glazing is used, preferably 1.4mm to 2.1 mm. The size of the glazing may vary widely depending on the application.

It is particularly advantageous if the glazing according to the invention is in the form of a laminated glazing and comprises a first glazing and a second glazing which are firmly connected to one another by at least one thermoplastic interlayer. The heating wire is arranged between the two panes, preferably embedded in a thermoplastic interlayer. Advantageously, the heating wires are arranged adjacent to the inner surfaces (side III, side II) of the outer and inner panes, respectively.

The thermoplastic interlayer comprises or consists of at least one thermoplastic material, preferably polyvinyl butyral (PVB), Ethylene Vinyl Acetate (EVA) and/or polyethylene terephthalate (PET). However, the thermoplastic interlayer may also comprise, for example, Polyurethane (PU), polypropylene (PP), polyacrylate, Polyethylene (PE), Polycarbonate (PC), polymethyl methacrylate, polyvinyl chloride, polyacetate resins, casting resins, acrylates, fluorinated ethylene-propylene, polyvinyl fluoride and/or ethylene-tetrafluoroethylene, or copolymers or mixtures thereof. The thermoplastic interlayer may be formed from one or more thermoplastic films stacked on top of each other, and the thickness of the thermoplastic films is preferably 0.6mm to 1.8mm, typically 0.76mm to 0.84 mm.

The glazing may have any three-dimensional shape. Preferably, the at least one pane is planar or slightly or strongly curved in one or more directions in space. The at least one glazing may be clear or tinted.

The heating wire is electrically connected to two collecting conductors, by means of which a (heating) current can be fed to the heating wire. The collecting conductor is preferably arranged in an edge region of the glazing along a side edge on the surface of the at least one pane. In a composite glazing, the two concentrating conductors are preferably arranged on its inner surface (side II or side III).

The width of each collecting conductor is preferably 2mm to 30mm, particularly preferably 4mm to 20 mm. The aggregate conductors are typically each in the form of a strip, the longer of which is referred to as the length, and the shorter of which is referred to as the width.

The aggregate conductor is formed as a conductive structure, for example printed and baked. The printed aggregate conductor comprises at least one metal, preferably silver. The electrical conductivity is preferably achieved by metal particles, particularly preferably by silver particles, contained in the aggregate conductor. The metal particles may be in an organic and/or inorganic matrix (e.g., paste or ink), preferably as a fired screen printing paste with glass frit. The layer thickness of the printed aggregate conductor is preferably 5 μm to 40 μm, more preferably 8 μm to 20 μm, most preferably 10 μm to 15 μm. Printed aggregate conductors with these thicknesses are technically easy to implement and have a favorable current-carrying capacity. Alternatively, the collecting conductor may also be formed as a strip of conductive film. The aggregate conductor then contains at least, for example, aluminum, copper, tin-plated 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. The aggregate conductor made of conductive films with these thicknesses is technically easy to implement and has a favorable current-carrying capacity. The aggregate conductor may be conductively connected to the heating wire, for example, by a solder compound, by a conductive adhesive, or by direct coating.

The first and/or second aggregate conductors may each include a plurality of discontinuous portions. For the purposes of the present invention, the term "first collecting conductor" or "second collecting conductor" also includes a collecting conductor made up of several discontinuous portions intended to be connected to the same pole or to the same potential of a voltage source.

Furthermore, the invention extends to a method of manufacturing a glazing according to the invention as described above. The features described in connection with the glazing are also applicable to the claimed method. The method comprises the following steps:

s1) providing at least one of the windowpanes,

s2) forming a first aggregate conductor and a second aggregate conductor, the first aggregate conductor comprising a first aggregate conductor segment and at least one second aggregate conductor segment;

s3), the heating wires including a first heating wire and a second heating wire, the electric heating field including a first heating field area and a second heating field area,

wherein the first focus conductor segment of the first focus conductor is guided around the hot-wire-free region in the following manner: such that the shortest distance between the first and second focus conductor segments is smaller than the shortest distance between the at least one second focus conductor segment and the second focus conductor, the first heating wire extending from the first focus conductor segment to the second focus conductor in the first heating field region and the second heating wire extending from the at least one second focus conductor segment to the second focus conductor in the second heating field region,

characterized in that the waviness of the first heating wire is greater than the waviness of the second heating wire, wherein the waviness is described by a relative value given by the length of the previously corrugated heating wire after stretching and the length of the unstretched corrugated heating wire in its direction of extension without taking into account the corrugation meandering,

wherein the waviness of the heating wires is configured such that a unit area heating power in the first heating field region corresponds to a unit area heating power in the second heating field region.

Preferably, the glazing according to the invention is manufactured in the form of a laminated glazing (composite glazing). For producing the laminated glazing, at least two glazings are preferably bonded (laminated) to each other under the action of heat, vacuum and/or pressure by means of at least one thermoplastic adhesive layer. The laminated glazing may be produced using processes known per se. For example, a so-called autoclave process may be carried out at a high pressure of about 10 to 15 bar and a temperature of 130 to 145 ℃ for about 2 hours. The vacuum bag or vacuum ring processes known per se operate at, for example, 90 ℃ to 120 ℃ and a vacuum level of 0.8 to 0.99 bar. The two glazings and the thermoplastic interlayer may also be pressed in a calender between at least one pair of rollers to form a composite glazing. Such plants for producing composite glazings are known and generally have at least one heating channel upstream of the pressing unit. The temperature during the pressing process ranges, for example, from 45 ℃ to 100 ℃. In practice, a combination of calendering and autoclave processes has proven particularly effective. Alternatively, a vacuum laminator may be used. They consist of one or more heatable and evacuable chambers, wherein the first pane and the second pane can be laminated at a reduced pressure of 0.01 mbar to 800 mbar and a temperature of 80 ℃ to 170 ℃ within, for example, about 60 minutes. The first glazing and the second glazing were then laminated in a vacuum laminator.

The heating wire is preferably embedded in the thermoplastic interlayer at side II and/or side III of the glazing. The heating wire is typically coated using a coating drum. In this process, the respective heating wire is moved together with the application head and unwound from the bobbin, which may be provided, in particular, with a degree of undulation. The heating wire is preferably heated during application so that the thermoplastic intermediate layer melts and bonds with the heating wire. In particular, the heating wire should penetrate completely or partially into the surface of the thermoplastic interlayer, embedding it in the interlayer. In laminated composite glazings, the heating wire is arranged between two glazings, in particular, for example, adjacent to a first glazing or adjacent to a second glazing. By using such an application head, heating wires having different waviness in the first and second heating field regions can be manufactured easily, quickly and very economically. This is an important advantage of the present invention.

The invention also extends to the use of the glazing according to the invention on buildings or in means of transport for land, air or water, in particular in motor vehicles, for example as a windscreen, rear window, side window and/or roof window. According to the invention, the glazing is preferably used in a motor vehicle.

The various embodiments of the invention may be implemented individually or in any combination. In particular, the features mentioned above and explained below can be used not only in the combination shown, but also in other combinations or alone without departing from the scope of the invention.

Drawings

The invention is explained in more detail below with the aid of embodiments with reference to the drawings. The figures show, in a simplified, not to scale representation:

fig. 1 is a top view of one embodiment of a glazing according to the invention, in the form of a laminated glazing,

figure 2 is a cross-sectional view of the composite glazing of figure 1,

figure 3 is a top view of an embodiment of the composite glazing of figure 1,

figure 4 is a top view of another embodiment of the composite glazing of figure 1,

figure 5 is a top view of another embodiment of the composite glazing of figure 1,

FIG. 6 is a flow chart illustrating the process of manufacturing a glazing according to the invention.

Detailed Description

Consider first fig. 1 and 2. Fig. 1 shows a top view of an embodiment of a glazing 1 according to the invention in a simplified schematic representation. Fig. 2 shows a cross-sectional view of the glazing 1 of fig. 1.

Glazing 1 is in the form of a laminated glazing and comprises a first glazing 2 (e.g. an outer glazing) and a second glazing 3 (e.g. an inner glazing) which are fixedly joined to one another by a thermoplastic interlayer 4. The heating wire 7 is embedded in the thermoplastic interlayer 4, here for example adjacent to the inner surface (side III) of the second pane 3 (see fig. 2). The glazing 1 may be installed in a building or motor vehicle and separates an interior space from the outside environment. For example, the glazing is a windshield of an automobile. Alternatively, the glazing has only a single pane, preferably in the form of a heat-strengthened single pane safety glass (not shown).

The first pane 2 and the second pane 3 are both made of glass, preferably thermally strengthened soda lime glass, and are transparent to visible light. The thermoplastic interlayer 4 consists of a thermoplastic material, preferably polyvinyl butyral (PVB), Ethylene Vinyl Acetate (EVA) and/or polyethylene terephthalate (PET).

The outer surface I of the first pane 2 faces the external environment and is also the outer surface of the glazing 1. Both the inner surface II of the first pane 2 and the outer surface III of the second pane 3 face the interlayer 4. The inner surface IV of the second pane 3 faces the interior of the building or vehicle and is also the inner surface of the glazing 1. It should be understood that the glazing 1 may have any suitable geometry and/or curvature. As a windshield, the glazing 1 typically has a convex curvature.

At the upper edge of the glazing 1, here for example in the centre, there is an electrical hot wire free region 8, here for example rectangular in shape. The glazing 1 has a first concentrating conductor 5 at the upper edge and a second concentrating conductor 6 at the lower edge. The relative indications "upper" and "lower" refer to typical installation states of the fitting glass 1, for example as a windshield. The two collecting conductors 5, 6 are conductively connected to each other by a heating wire 7, which heating wire 7 extends from the first collecting conductor 5 to the second collecting conductor 6. The heating wires 7 form an electric heating field. The heating wires each extend at least substantially perpendicularly to the collecting conductors 5, 6.

The first collecting conductor 5 is routed in the first collecting conductor section 5.1 around a hot-wire-free region 8, wherein the hot-wire-free region 8 serves, for example, as a communication window. Here, the first aggregated conductor segment 5.1 is routed around the hot-wire-free region 8 below the hot-wire-free region 8. Adjacent to the first aggregated conductor segment 5.1 are two second aggregated conductor segments 5.2 which are not routed around the hot-filament-free region 8. The first aggregate conductor 5 consists of a first aggregate conductor segment 5.1 and two second aggregate conductor segments 5.2. The shortest (here vertical) distance between the first 5.1 and the second collecting conductor 6 is smaller than the shortest (here vertical) distance between each second collecting conductor segment 5.2 and the second collecting conductor 6.

The first 5.1 and the second 6 focus conductor segments are electrically connected to each other by a first heating wire 7.1, the first heating wire 7.1 extending from the first focus conductor segment 5.1 to the second focus conductor 6. The first heating wire 7.1 forms a first heating field region H1. The two second collecting conductor segments 5.2 and the second collecting conductor 6 are electrically connected to each other by means of a second heating wire 7.2, which second heating wire 7.2 extends from the two second collecting conductor segments 5.2 to the second collecting conductor 6. The second heating wire 7.2 forms two second heating field regions H2. The heating field consists of a first heating field zone H1 and two second heating field zones H2.

The two collecting conductors 5, 6 are intended to be connected to a voltage source in order to feed the heating wire 7 with current and to electrically heat the glazing 1.

Although not shown in fig. 1, the first and second aggregate conductors 5, 6 may each be made up of two or more discrete portions, wherein the two or more discrete portions of the first aggregate conductor 5 are for connection to a first pole or potential of a voltage source and the two or more discrete portions of the second aggregate conductor 6 are for connection to a second pole or potential (different from the first potential) of the voltage source. For example, the first collecting conductor 5 and the second collecting conductor 6 may each be constituted by two discontinuous portions, so that the heating field is divided into two separate portions, for example two at least substantially symmetrical portions, which are separated by a non-heated region, for example in an intermediate position of the glazing 1. For example, the unheated zone (e.g. in the middle position) has a width (measured parallel to the collecting conductors 5, 6) of 5 to 7 mm.

If the heating wires 7 in the first heating field region H1 and the second heating field region H2 have the same design, apart from their length, the heating power per unit area (window pane area) is greater in the first heating field region H1 than in the two second heating field regions H2, since the first heating wire 7.1 is shorter in length compared to the second heating wire 7.2. This situation will be avoided according to the invention, which will be explained below with reference to fig. 3 to 5 later.

Fig. 3 shows a detailed cross section of the embodiment of the glazing 1 of fig. 1 in the area of the hot-wire-free region 8, which is not claimed in the claims. Although only a part of the glazing 1 of fig. 1 is shown in fig. 3, it should be understood that the first heating wires 7.1 in the first heating field regions H1 all have the same design, i.e. are formed in the same way with respect to the features described. Correspondingly, the second heating wires 7.2 in both second heating field regions H2 have the same design, i.e. are formed in the same way with respect to the described features.

The first heating wire 7.1 in the first heating field region H1 and the second heating wire 7.2 in the two second heating field regions H2 differ in that the diameter of the first heating wire 7.1 is smaller than the diameter of the second heating wire 7.2. By this measure, the resistance of the first heating wire 7.1 can be increased compared to the resistance of the second heating wire 7.2, so that a homogenization of the heating power per unit area of the entire heating field can be achieved.

Similar to fig. 3, fig. 4 shows a detailed cross section of the embodiment of the glazing 1 of fig. 1 in the area of the hot-wire-free region 8 not claimed in the claims. In this embodiment, the first heating wire 7.1 in the first heating field region H1 and the second heating wire 7.2 in the two second heating field regions H2 differ in that the distance between the first heating wires 7.1 is greater than the distance before the second heating wire 7.2. This measure allows the heating power in the first heating field region H1 to be reduced compared to the two second heating field regions H2, so that a homogenization of the heating power per unit area of the entire heating field can be achieved.

Similar to fig. 3, fig. 5 shows a detailed cross-section of the embodiment of the glazing 1 of fig. 1 according to the invention in the area of the hot-wire-free region 8. In this embodiment, the first heating wire 7.1 in the first heating field region H1 and the second heating wire 7.2 in the two second heating field regions H2 differ in that the first heating wire 7.1 has a greater waviness than the second heating wire 7.2. As a result of this measure, since the length of the first heating wire 7.1 is longer than the length of the second heating wire 7.2, the heating power in the first heating field region H1 can be reduced compared to the two second heating field regions H2, so that a homogenization of the heating power per unit area of the entire heating field can be achieved.

The embodiments of the glazing according to the invention shown with the aid of fig. 3 to 5 can be provided individually or in any combination.

FIG. 6 shows a manufacturing flow diagram of a glazing according to the invention, comprising steps S1 to S3:

s1) providing at least one

pane

2, 3,

s2) forming the first and second aggregate conductors 5, 6, wherein the first aggregate conductor sections 5.1 of the first aggregate conductor 5 are guided around the filament-free region 8 in the following manner: such that the shortest distance between the first 5.1 and the second 6 aggregation conductor sections is smaller than the shortest distance between the at least one second 5.2 of the first aggregation conductor 5 and the second aggregation conductor 6, the first heating wire 7.1 extends in the first heating field region H1 from the first aggregation conductor section 5.1 to the second aggregation conductor 6, and the second heating wire 7.2 extends in the second heating field region H2 from the at least one second aggregation conductor section 5.2 to the second aggregation conductor 6,

s3) forming the heating wire 7, wherein the waviness of the first heating wire 7.1 is greater than the waviness of the second heating wire 7.2. Optionally, the electrical resistance of the first heating filament in the first heating field region is greater than the electrical resistance of the second heating filament in the at least one second heating field region, and/or the distance between directly adjacent first heating filaments in the first heating field region is greater than the distance between directly adjacent second heating filaments in the at least one second heating field region. All features of step S3) are configured such that the heating power per unit area in the first heating field region H1 corresponds to the heating power per unit area in the at least one second heating field region H2.

In the manufacture of a composite glazing, the method comprises the step of laminating two

glazings

2, 3 by means of at least one thermoplastic layer 4.

In summary, the invention provides an improved glazing with a heating field, by means of which a uniform heating power can be achieved in an advantageous manner throughout the heating field. The glazing according to the invention can be produced simply and inexpensively using known production processes.

List of reference numerals

1 glazing

2 first pane

3 second pane

4 thermoplastic interlayer

5 first collecting conductor

5.1 first concentrating conductor section

5.2 second assembled conductor segment

6 second aggregation conductor

7 electric heating wire

7.1 first heating wire in the first heating field region H1

7.2 second heating wire in second heating field region H2

8 zone without electric heating wire

H1 first heating field area

H2 second heating field area

Claims

1. Glazing (1) with an electric heating field (H1, H2), comprising:

-at least one pane (2, 3),

-a first (5) and a second (6) collecting conductor provided for connection to a voltage source, which are connected to each other by means of heating wires (7) such that an electrical heating field (H1, H2) is formed between the two collecting conductors (5, 6), the heating wires (7) comprising a first (7.1) and a second (7.2) heating wire, the electrical heating field (H1, H2) comprising a first (H1) and a second (H2) heating field region, and the first collecting conductor (5) comprising a first (5.1) collecting conductor segment and at least one second (5.2) collecting conductor segment,

-at least one hot-wire-free region (8) outside the heating field (H1, H2),

wherein the first collecting conductor section (5.1) of the first collecting conductor (5) is guided around the hot-wire-free region (8) in the following manner: such that the shortest distance between the first concentrating conductor segment (5.1) and the second concentrating conductor (6) is smaller than the shortest distance between the at least one second concentrating conductor segment (5.2) of the first concentrating conductor (5) and the second concentrating conductor (6), the first heating wire (7.1) extending from the first concentrating conductor segment (5.1) to the second concentrating conductor (6) in the first heating field region (H1), the second heating wire (7.2) extending from the at least one second concentrating conductor segment (5.2) to the second concentrating conductor (6) in the second heating field region (H2),

characterized in that the waviness of the first heating wire (7.1) is greater than the waviness of the second heating wire (7.2), wherein the waviness is described by a relative value given by the length of the previously corrugated heating wire after stretching and the length of the unstretched corrugated heating wire in its direction of extension without taking into account the corrugation meandering,

wherein the waviness of the heating wires (7.1, 7.2) is configured such that the heating power per unit area in the first heating field region (H1) corresponds to the heating power per unit area in the second heating field region (H2).

2. A glazing (1) according to claim 1, wherein the waviness of the first heating wire (7.1) is 20% to 30%, in particular 25%, greater than the waviness of the second heating wire (7.2).

3. The glazing (1) according to claim 2, wherein the waviness of the heating wire (7) is formed such that the length of the corrugated heating wire (7) is increased to 1.1 to 1.4 times due to stretching.

4. Glazing (1) according to any of claims 1 to 3,

wherein the heating wire (7.1, 7.2) has at least one of the following characteristics i) and ii):

i) the resistance of the first heating wire (7.1) is greater than the resistance of the second heating wire (7.2), in particular wherein the diameter of the first heating wire (7.1) is smaller than the diameter of the second heating wire (7.2),

ii) the distance between directly adjacent first heating wires (7.1) is larger than the distance between directly adjacent second heating wires (7.2),

wherein the features i) and/or ii) are configured such that the heating power per unit area in the first heating field region (H1) corresponds to the heating power per unit area in the at least one second heating field region (H2).

5. Glazing (1) according to claim 4, characteristic i), wherein the diameter of the first heating wire (7.1) is 20% to 30%, in particular 25%, smaller than the diameter of the second heating wire (7.2), wherein the diameter of the heating wire (7) is in particular from 10 μ ι η to 200 μ ι η, in particular from 15 μ ι η to 35 μ ι η, and in particular from 18 μ ι η to 29 μ ι η.

6. Glazing (1) according to claim 4, ii), 5, wherein the spacing of directly adjacent first heating wires (7.1) is 20% to 30%, in particular 25%, greater than the spacing of directly adjacent second heating wires (7.2), wherein the spacing of directly adjacent heating wires (7) in the heating field (H1, H2) is in particular in the range of 2 to 3 mm.

7. Glazing (1) according to any of claims 1 to 6, wherein the first aggregate conductor (5) comprises a plurality of discontinuous portions intended to be connected to the same pole of a voltage source or to the same potential.

8. Glazing (1) according to any of claims 1 to 7, wherein the second concentrating conductor (6) comprises a plurality of discontinuous portions to be connected to the same pole of a voltage source or to the same potential.

9. Glazing (1) according to any of claims 1 to 8, wherein the linear resistance of the heating wire (7) is in the range of 100 to 220 ohm/m.

10. Glazing (1) according to any of claims 1 to 9, wherein the length of the heating wire (7) is in the range of 70 to 90 cm.

11. Glazing (1) according to any of claims 1 to 10, wherein the heating wire (7) comprises or consists of aluminium, copper, tin-coated copper, gold, silver, zinc, tungsten and/or tin or alloys thereof, in particular copper and/or tungsten.

12. Glazing according to any of claims 1 to 11, wherein the at least one pane (2, 3) comprises or consists of glass, in particular soda lime glass, or plastic, in particular preferably rigid plastic, in particular polycarbonate or polymethyl methacrylate.

13. Glazing according to any of claims 1 to 12, in the form of a laminated glazing comprising a first glazing (2) and a second glazing (3) connected to each other by at least one thermoplastic interlayer (4), heating wires (7) being arranged between the two glazings (1, 2), in particular embedded in the thermoplastic interlayer (4).

14. Method of manufacturing a glazing (1), in particular a laminated glazing, with an electric heating field (1 HH1, H2) according to any of claims 1 to 13, comprising the steps of:

s1) providing at least one pane (2, 3),

s2) forming a first aggregate conductor (5) and a second aggregate conductor (6), the first aggregate conductor comprising first aggregate conductor segments (5.1) and at least one second aggregate conductor segment (5.2);

s3), the electric heating wire (7) is formed, the electric heating wire (7) comprises a first electric heating wire (7.1) and a second electric heating wire (7.2), the electric heating field comprises a first heating field area (H1) and a second heating field area (H2),

wherein the first collecting conductor section (5.1) of the first collecting conductor (5) is guided around the hot-wire-free region (8) in the following manner: such that the shortest distance between the first (5.1) and the second (6) aggregation conductor section is smaller than the shortest distance between the at least one second (5.2) and the second (6) aggregation conductor, the first heating wire (7.1) extends from the first (5.1) to the second (6) aggregation conductor section in the first heating field region (H1), and the second heating wire (7.2) extends from the at least one second (5.2) to the second (6) aggregation conductor section in the second heating field region (H2),

wherein the waviness of the heating wires (7) is configured such that the heating power per unit area in the first heating field region (H1) corresponds to the heating power per unit area in the second heating field region (H2).

15. Use of a glazing (1) according to any of claims 1 to 13 on a building, in a vehicle for land, air or water, in particular in a motor vehicle, for example as a windscreen, a rear window, a side window and/or a roof window.