EP4278861A1 - Glazing with electric heating field - Google Patents

Glazing with electric heating field

Info

Publication number
EP4278861A1
EP4278861A1 EP22702616.8A EP22702616A EP4278861A1 EP 4278861 A1 EP4278861 A1 EP 4278861A1 EP 22702616 A EP22702616 A EP 22702616A EP 4278861 A1 EP4278861 A1 EP 4278861A1
Authority
EP
European Patent Office
Prior art keywords
heating
heating wires
collecting conductor
wires
glazing
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP22702616.8A
Other languages
German (de)
French (fr)
Inventor
Bretislav PROKOP
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Saint Gobain Glass France SAS
Compagnie de Saint Gobain SA
Original Assignee
Saint Gobain Glass France SAS
Compagnie de Saint Gobain SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Saint Gobain Glass France SAS, Compagnie de Saint Gobain SA filed Critical Saint Gobain Glass France SAS
Publication of EP4278861A1 publication Critical patent/EP4278861A1/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00—Ohmic-resistance heating
    • H05B3/84—Heating arrangements specially adapted for transparent or reflecting areas, e.g. for demisting or de-icing windows, mirrors or vehicle windshields
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B2203/00—Aspects relating to Ohmic resistive heating covered by group H05B3/00
    • H05B2203/002—Heaters using a particular layout for the resistive material or resistive elements
    • H05B2203/008—Heaters using a particular layout for the resistive material or resistive elements with layout including a portion free of resistive material, e.g. communication window
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B2203/00—Aspects relating to Ohmic resistive heating covered by group H05B3/00
    • H05B2203/011—Heaters using laterally extending conductive material as connecting means
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B2203/00—Aspects relating to Ohmic resistive heating covered by group H05B3/00
    • H05B2203/014—Heaters using resistive wires or cables not provided for in H05B3/54

Definitions

  • the invention is in the technical field of glazing manufacture and relates to a glazing with an electric heating field, a method for its manufacture and its use.
  • the field of vision of a vehicle window must be kept free of ice and fogging.
  • a stream of air heated by engine heat can be directed onto the windows.
  • the pane can have an electrical heating function, whereby a heating field is formed by electrically heatable structures.
  • Composite panes are known, for example, which have a transparent, electrically conductive coating on an inner surface of one of the individual panes.
  • An external voltage source can be used to conduct an electric current through the electrically conductive coating, which heats the coating and thus the pane.
  • WO2012/052315 A1 discloses, for example, such a heatable metal-based coating.
  • electrically heatable metal wires which are usually embedded in the thermoplastic interlayer in composite panes.
  • the electrical contacting of the electrically heatable structures is typically made via collecting conductors (busbars), as known for example from US 2007/0020465 A1.
  • the collecting conductors consist, for example, of a printed and baked-on silver paste.
  • the collecting conductors typically run along the top and bottom edges of the pane.
  • the collecting conductors collect current flowing through the electrically heatable structures and conduct it to external leads connected to a voltage source.
  • Panes with electrically heatable structures shield electromagnetic radiation relatively strongly, so that radio data communications can be significantly impaired, especially in motor vehicles with an electrically heatable windshield.
  • Electrically heatable windshields are therefore often provided with zones ("communication windows") in which the electrically heatable structures are not formed. These communication windows are well permeable at least for certain ranges of the electromagnetic spectrum and in this way enable smooth data traffic through the pane.
  • the communication windows where electronic devices such as sensors, cameras and the like can be located, are often arranged near the upper edge of the pane, where they can be well concealed by an upper masking strip.
  • communication windows due to their spatial extension, affect the heating properties of the electrically heatable structures, which, at least locally, affects the heating power per area. In fact, they cause a highly inhomogeneous heating power distribution, with the heating power below and in the vicinity of the communication windows being significantly altered. As a result, very different pane temperatures can occur, imposing large thermal stresses on the panes. In addition, adhesion points of add-on parts can become detached as a result.
  • thermoelectric thermoelectric
  • JP H0872674 A dislocses a pane having electric heating wires that may vary in diameter and/or inter-distance.
  • the object of the present invention is to provide an improved glazing with an electric heating field with which these disadvantages can be avoided.
  • the glazing should be easy and inexpensive to manufacture in industrial series production.
  • an electrically heatable glazing with an electric heating field is shown, which typically, but not necessarily, serves to separate an interior from an external environment.
  • the glazing according to the invention can in principle be of any design, in particular as insulating glazing in which at least two panes are spaced apart by at least one spacer, as thermally toughened single-pane safety glass or as laminated pane.
  • the glazing according to the invention is designed as a laminated pane and comprises a first pane having an outer side and an inner side and a second pane having an inner side and an outer side, which are firmly bonded to one another by at least one thermoplastic intermediate layer (adhesive layer).
  • the first pane may also be referred to as the outer pane
  • the second pane may be referred to as the inner pane.
  • the surfaces or sides of the two individual panes are usually referred to as side I, side II, side III and side IV from the outside inwards.
  • the glazing according to the invention comprises at least one pane as well as a first collecting conductor and a second collecting conductor, which are provided for connection to a voltage source and are interconnected by a plurality of electric heating wires in such a way that an electric heating field is formed between the first collecting conductor and the second collecting conductor.
  • the electrical heating wires are 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 connected directly to the two collecting conductors, the heating field being formed by the heating wires.
  • At least one heating-wire-free zone is provided outside the heating field, which can serve in particular as a communication window.
  • the heating-wire-free zone is arranged at an upper edge of the glazing, in particular at least approximately in the center of the pane.
  • One or more sensors can be arranged at the heatingwire-free zone in the interior of, for example, a vehicle.
  • the heating-wire-free zone does not have any heating wires, since these can negatively influence the passage of electromagnetic radiation through the zone, and thus the functionality of sensors.
  • the heating-wire-free zone may have any suitable geometric shape, preferably the heating-wire-free zone is rectangular or trapezoidal in shape. Alternatively, an oval, circular, polygonal or any other suitable shape may be selected for the heating-wire-free zone.
  • a first collecting conductor section of the first collecting conductor is guided around the heating-wire-free zone in such a way that a shortest distance between the first collecting conductor section and the second collecting conductor is smaller than a shortest distance between at least one second collecting conductor section of the first collecting conductor and the second collecting conductor.
  • the at least one second collecting conductor section is arranged adjacent to the first to the first collecting conductor section, wherein a second collecting conductor section may be arranged adjacent to each side of the first collecting conductor section, in which case the first collecting conductor is composed of a first collection conductor section and two second collecting conductor sections adjacent thereto.
  • First heating wires extend from the first collecting conductor section to the second collecting conductor, the first heating wires forming a first heating field region.
  • Second heating wires extend from the at least one second collecting conductor section, in particular from two second collecting conductor sections, to the second collecting conductor, the second heating wires forming at least one second heating field region, in particular two second heating field regions.
  • the heating wires are thus divided into or composed of the first heating wires and the second heating wires.
  • the first heating wires are spatially separated from the second heating wires. Accordingly, the heating field is divided into or composed of a first heating field region (defined by the first heating wires) and at least one second heating field region (defined by the second heating wires), in particular two second heating field regions.
  • the at least one second heating field region, in particular two second heating field regions is or are spatially separated from the first heating field region.
  • the first heating wires in the first heating field region and the second heating wires in the at least one second heating field region are formed differently from each other. Stated more particularly, the first heating wires differ from the second heating wires in their waviness, with the waviness of the first heating wires in the first heating field region being greater than the waviness of the second heating wires in the at least one second heating field region.
  • the waviness of the heating wires is designed in such a way that a heating power per area (pane area) in the first heating field region corresponds to a heating power per area (pane area) in the at least one second heating field region.
  • the present invention is based on the insight that, due to a shorter distance between the two collecting conductors in that section of the first collecting conductor which is routed around the heating-wire-free zone, an increase in the heating power per area occurs in comparison to the rest of the heating field due to a reduction in the length of the otherwise identically formed heating wires and a thus resulting reduction in the length-dependent electrical resistance of the heating wires (resistance per length, as measured in ohms/m). This leads to an undesirable inhomogeneous heating power per area in the entire heating field.
  • a homogenization of the heating power per area in the entire heating field can be achieved in an advantageous manner by modifying the waviness of the heating wires.
  • the heating wire-free zone can thus be suitably formed in size, shape and position according to its function, for example as a communication window, without taking into account any thermal inhomogeneities.
  • the heating field is formed by the electric heating wires extending between the first collecting conductor and the second collecting conductor, the two collecting conductors being electrically connected by the heating wires.
  • 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.
  • the heating wires in the heating field are formed such that a waviness of the first heating wires in the first heating field region is greater than a waviness of the second heating wires in the at least one second heating field region.
  • a heating wire is regarded as "wavy", i.e. provided with waviness, if it has an undulating, in particular meandering (for example sinusoidal), course along its extension.
  • a wavy heating wire extends along a (e.g. linear) direction of extension and exhibits wavy deflections perpendicular to the direction of extension.
  • the length of the wavy heating wire measured along its extension direction is inevitably shorter than the actual length of the heating wire taking into account the deflections.
  • the waviness of a heating wire can be determined in a simple manner by stretching a wavy heating wire into a straight-line form, whereby the waviness can be described by a relative value as given by the length of the stretched (previously wavy) heating wire and the length of the (nonstretched) wavy heating wire along its direction of extension without taking wavy deflections into account. It is understood, that a same heating wire is considered for determining the waviness of the heating wire.
  • the length of a wavy heating wire can be extended by 10% by stretching it into a straight-line form, this results in a relative value of 1.1 (length of straight-line heating wire after stretching / length of wavy heating wire along its stretching direction before stretching).
  • Heating wires used in a glazing according to the invention are provided with a waviness, i.e. they have an undulating course which differs from the straight-line course.
  • the waviness of the heating wire changes its length and thus also the length-dependent electrical resistance of the heating wire (as measured in Ohm/m).
  • the first heating wires are provided with such a waviness that each first heating wire is subject to an increase in length by a factor in the range 1.1 to 1.4 due to stretching. This measure makes it possible to achieve good homogenization of the heating power per area, particularly in the case of conventional vehicle glazing, such as a windshield with a heating-wire-free zone arranged at the upper edge of the pane.
  • An electrical resistance of the first heating wires in the first heating field region is greater than an electrical resistance of the second heating wires in the at least one second heating field region.
  • a distance between immediately adjacent first heating wires in the first heating field region is greater than a distance between immediately adjacent second heating wires in the at least one second heating field region.
  • features i) and/or ii) are designed in such a way that a heating power per area (pane area) in the first heating field region corresponds to a heating power per area (pane area) in the at least one second heating field region.
  • the heating wires in the heating field are designed such that an electrical resistance of the first heating wires in the first heating field region is greater than an electrical resistance of the second heating wires in the at least one second heating field region. Due to the higher electrical resistance of the first heating wires, the heating power per area in the first heating field area can be reduced in an advantageous manner compared to the heating power per region in the at least one second heating field region.
  • An increase in electrical resistance can in principle be achieved in any way, for example by choosing a material for the first heating wires that is different from the material of the second heating wires which has a higher electrical resistance.
  • the material of the heating wires is the same and the diameter of the first heating wires in the first heating field region is smaller than the diameter of the second heating wires in the at least one second heating field region.
  • the diameter of the first heating wires in the first heating field region is 20% to 30%, in particular 25%, smaller than the diameter of the second heating wires in the at least one second heating field region, as a result of which good homogenization of the heating power per area can be achieved, in particular in the case of conventional vehicle glazing such as a windshield with a heating-wire-free zone arranged at the upper edge of the pane.
  • the diameter of the heating wires is from 10 pm to 200 pm, in particular from 15 pm to 35 pm and especially from 18 pm to 29 pm.
  • the heating wires in the heating field are formed such that a distance between directly adjacent first heating wires in the first heating field region is greater than a distance between directly adjacent second heating wires in the at least one second heating field region. Due to the larger 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.
  • the distance between directly adjacent first heating wires in the first heating field region is 20% to 30%, in particular 25%, greater than a distance between directly adjacent second heating wires in the second heating field region.
  • the distance between directly adjacent heating wires in the heating field is in the range of 2 to 3 mm.
  • the length-dependent electrical resistance of the heating wires is in the range of 100 to 220 Ohm/m.
  • the heating wires in the heating field have a length in the range of 50 to 200 cm depending on the height of the glazing.
  • the heating wires can be heated electrically and, for this purpose, consist of an electrically conductive material that can basically be selected as desired.
  • the heating wires consist of a metallic material.
  • the heating wires contain or consist of aluminum, copper, tinned copper, gold, silver, zinc, tungsten and/or tin or alloys thereof, in particular copper and/or tungsten.
  • the first heating wires may consist of a material that is the same as or different from the material of the second heating wires.
  • the at least one pane preferably contains or consists of 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.
  • Suitable glasses are known, for example, from EP 0 847 965 B1 .
  • the thickness of the at least one pane can vary widely and be adapted to the requirements of the individual case.
  • panes with standard thicknesses of 1 .0 mm to 25 mm and preferably 1 .4 mm to 2.1 mm are used.
  • the size of the panes can vary widely and depends on the use.
  • the glazing according to the invention is in the form of a laminated pane and comprises a first pane and a second pane which are firmly connected to one another by at least one thermoplastic intermediate layer.
  • the electrical heating wires are arranged between the two panes, preferably embedded in the thermoplastic intermediate layer.
  • the heating wires are arranged adjacent to an inner surface (side III, side II) of the outer pane and inner pane, respectively.
  • the thermoplastic intermediate layer contains or consists of at least one thermoplastic, preferably polyvinyl butyral (PVB), ethylene vinyl acetate (EVA) and/or polyethylene terephthalate (PET).
  • the thermoplastic interlayer may also include, for example, polyurethane (PU), polypropylene (PP), polyacrylate, polyethylene (PE), polycarbonate (PC), polymethyl metacrylate, polyvinyl chloride, polyacetate resin, casting resin, acrylate, fluorinated ethylenepropylene, polyvinyl fluoride and/or ethylene-tetrafluoroethylene, or a copolymer or mixture thereof.
  • the thermoplastic interlayer can be formed by one or more thermoplastic films stacked on top of each other, and the thickness of a thermoplastic film is preferably from 0.6 mm to 1 .8 mm, typically 0.76 mm to 0.84 mm.
  • the glazing may have any three-dimensional shape.
  • the at least one pane is planar or slightly or strongly curved in one direction or in multiple directions of space.
  • the at least one pane may be colorless or colored.
  • the heating wires are electrically connected to two collecting conductors through which a (heating) current can be fed into the heating wires.
  • the collecting conductors are preferably arranged in the edge region of the glazing along a side edge on a surface of the at least one pane.
  • the two collecting conductors are preferably arranged on an inner surface (side II or side III) thereof.
  • the width of a respective collecting conductor is preferably from 2 mm to 30 mm, particularly preferably from 4 mm to 20 mm.
  • the collecting conductors are typically each in the form of a strip, the longer of its dimensions being referred to as the length and the less long of its dimensions being referred to as the width.
  • Collecting conductors are formed, for example, as printed and baked-on conductive structures.
  • the printed collecting conductor contains at least one metal, preferably silver.
  • the electrical conductivity is preferably realized via metal particles contained in the collecting conductor, particularly preferably via silver particles.
  • the metal particles can be in an organic and/or inorganic matrix such as pastes or inks, preferably as fired screen printing paste with glass frits.
  • the layer thickness of the imprinted collecting conductor is preferably from 5 pm to 40 pm, more preferably from 8 pm to 20 pm and most preferably from 10 pm to 15 pm.
  • Printed collecting conductors with these thicknesses are technically easy to realize and have an advantageous current-carrying capacity.
  • the collecting conductor can also be formed as a strip of electrically conductive film.
  • the collecting conductor 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 10 pm to 500 pm, particularly preferably 30 pm to 300 pm. Collecting conductors made of electrically conductive films with these thicknesses are technically easy to realize and have an advantageous current-carrying capacity.
  • the collecting conductors can be electrically conductively connected to the heating wires, for example, via a solder compound, via an electrically conductive adhesive or by direct application.
  • the first collecting conductor and/or the second collection conductor may each comprise a plurality of non-contiguous parts.
  • first collecting conductor or “second collecting conductor” also includes a collecting conductor consisting of several non-contiguous parts, wherein the non-contiguous parts serve to be connected to a same pole of a voltage source or a same electrical potential.
  • the invention extends to a method of manufacturing a glazing according to the invention as-above desribed.
  • the features described in connection with the glazing also apply to the claimed method.
  • the method comprising the following steps:
  • first collecting conductor comprising a first collecting conductor section and at least one second collecting conductor section;
  • the heating wires comprising first heating wires and second heating wires, the electric heating field comprising a first heating field region and a second heating field region, wherein the first collecting conductor section of the first collecting conductor is guided around a heating-wire-free zone in such a way that a shortest distance between the first collecting conductor section and the second collecting conductor is smaller than a shortest distance between the at least one second collecting conductor section and the second collecting conductor, the first heating wires extending in the first heating field region from the first collecting conductor section to the second collecting conductor, and in the second heating field region second heating wires extending from the at least one second collecting conductor section to the second collecting conductor, characterized in that a waviness of the first heating wires is greater than a waviness of the second heating wires, with waviness being described by a relative value as given by the length of a stretched, previously wavy, heating wire and the length of the, non-stretched, wavy heating wire
  • the glazing according to the invention is manufactured in the form of a laminated pane (composite pane).
  • a laminated pane For the production of a laminated pane, at least two panes are preferably bonded (laminated) to one another under the action of heat, vacuum and/or pressure by means of at least one thermoplastic adhesive layer.
  • Processes known per se can be used to produce a laminated pane. For example, so-called autoclave processes can be carried out at an elevated pressure of about 10 bar to 15 bar and temperatures of 130 °C to 145 °C for about 2 hours.
  • Vacuum bag or vacuum ring processes known per se operate, for example, at 90 °C to 120 °C and vacuum level of 0.8 to 0.99 bar.
  • the two panes and the thermoplastic intermediate layer can also be pressed in a calender between at least one pair of rolls to form a composite pane.
  • Plants of this type are known for the production of composite panes and usually have at least one heating tunnel upstream of a pressing unit.
  • the temperature during the pressing process ranges, for example, from 45 °C to 100 °C. Combinations of calender and autoclave processes have proved particularly effective in practice.
  • vacuum laminators can be used. These consist of one or more chambers which can be heated and evacuated and in which the first pane and second pane can be laminated within, for example, about 60 minutes at reduced pressures of 0.01 mbar to 800 mbar and temperatures of 80°C to 170°C. The first pane and the second pane are then laminated in a vacuum laminator.
  • the heating wires are preferably embedded in the thermoplastic intermediate layer at side II and/or side III of the panes.
  • the heating wires are typically applied using an application drum.
  • a respective heating wire is moved with an application head and unwound from a spool, and, in particular, can be provided with waviness.
  • the heating wire is preferably heated during application so that the thermoplastic intermediate layer melts and bonds with the heating wire.
  • the heating wire is to penetrate fully or partially into the surface of the thermoplastic interlayer so that it is embedded in the interlayer.
  • the heating wires are arranged between the two panes, in particular, for example, adjacent to the first pane or adjacent to the second pane. Heating wires having different waviness in the first and second heating field regions can readily, fast and very economically be made by using such application head. This is an important advantage of the present invention.
  • the invention extends to the use of the glazing according to the invention on buildings or in means of transport for traffic on land, in the air or on water, in particular in motor vehicles, for example as a windshield, rear window, side windows and/or roof window.
  • motor vehicles for example as a windshield, rear window, side windows and/or roof window.
  • the use of the glazing in motor vehicles is preferred.
  • Fig. 1 a top view of an embodiment of the glazing according to the invention, which is in the form of a laminated pane,
  • Fig. 2 a cross-sectional view of the composite pane of Fig. 1 ,
  • Fig. 3 a top view of an embodiment of the composite pane of Fig. 1 ,
  • Fig. 4 a top view of a further embodiment of the composite pane of Fig. 1 ,
  • Fig. 5 a top view of a further embodiment of the composite pane of Fig. 1 ,
  • Fig. 6 a flow chart illustrating the process of manufacturing a glazing according to the invention.
  • Figure 1 shows a top view of an embodiment of the glazing 1 according to the invention in a simplified, schematic representation.
  • a cross-sectional view of the glazing 1 of Figure 1 is shown in Figure 2.
  • the glazing 1 is in the form of a laminated pane and comprises a first pane 2 (e.g. outer pane) and a second pane 3 (e.g. inner pane), which are firmly connected to one another by a thermoplastic intermediate layer 4. Heating wires 7 are embedded in the thermoplastic intermediate layer 4, here for example adjacent to the inner surface (side III) of the second pane 3 (see Figure 2).
  • the glazing 1 can be installed in a building or motor vehicle and separates an interior space from an external environment.
  • the glazing is the windshield of a motor vehicle.
  • the glazing has only a single pane, preferably in the form of a thermally toughened single-pane safety glass (not shown).
  • the first pane 2 and the second pane 3 are each made of glass, preferably thermally toughened soda-lime glass, and are transparent to visible light.
  • the thermoplastic intermediate layer 4 consists of a thermoplastic, 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.
  • the inner surface II of the first pane 2 and the outer surface III of the second pane 3 each face the intermediate layer 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 .
  • the glazing 1 may have any suitable geometric shape and/or curvature. As a windshield, the glazing 1 typically has a convex curvature.
  • the glazing 1 has a first collecting conductor 5 at the upper edge and a second collecting conductor 6 at the lower edge.
  • the relative indications "upper” and “lower” refer to the typical installation state of the glazing 1 , for example as a windshield.
  • the two collecting conductors 5, 6 are electrically conductively connected to each other by heating wires 7, the heating wires 7 extending from the first collecting conductor 5 to the second collecting conductor 6.
  • An electric heating field is formed by the electric heating wires 7.
  • the heating wires each extend at least approximately perpendicular to the collecting conductors 5, 6.
  • the first collecting conductor 5 is routed around the heating-wire-free zone 8 in a first collecting conductor section 5.1 , which here, for example, serves as a communication window.
  • the first collecting conductor section 5.1 is routed around the heating-wire-free zone 8 below the heating-wire-free zone 8.
  • Adjacent to the first collecting conductor section 5.1 are two second collecting conductor sections 5.2, which are not routed around the heating-wire-free zone 8.
  • the first collecting conductor 5 is composed of the first collecting conductor section 5.1 and the two second collecting conductor sections 5.2.
  • the shortest (here vertical) distance between the first collecting conductor section 5.1 and the second collecting conductor 6 is less than the shortest (here vertical) distance between each second collecting conductor section 5.2 and the second collecting conductor 6.
  • the first collecting conductor section 5.1 and the second collecting conductor 6 are electrically connected to each other by first heating wires 7.1 , the first heating wires 7.1 extending from the first collecting conductor section 5.1 to the second collecting conductor 6.
  • the first heating wires 7.1 form a first heating field region H1 .
  • the two second collection conductor sections 5.2 and the second collecting conductor 6 are electrically connected to each other by second heating wires 7.2, the second heating wires 7.2 extending from the two second collecting conductor sections 5.2 to the second collecting conductor 6.
  • the second heating wires 7.2 form two second heating field regions H2.
  • the heating field is composed of the first heating field region H1 and the two second heating field regions H2.
  • the two collecting conductors 5, 6 are used to be connected to an electrical voltage source in order to feed the heating wires 7 with electrical current and to electrically heat the glazing 1 .
  • first collecting conductor 5 and the second collecting conductor 6 may each consist of two or more non-contiguous parts, wherein the two or more non-contiguous parts of the first collecting conductor 5 serve to be connected to a first pole of a voltage source or a first electrical potential and the two or more non-contiguous parts of the second collecting conductor 6 serve to be connected to a second pole of the voltage source or a second electrical potential (different from the first electrical potential).
  • both the first collecting conductor 5 and the second collecting conductor 6 may each consist of two non-contiguous parts so that the heating field is divided into two separate portions, e.g. two at least approximately symmetrical portions which are separated by a non-heated region, e.g. in a middle position of the glazing 1 .
  • the non-heated region e.g. in a middle position, has a width (as measured parallel to the collecting conductors 5, 6) of 5 to 7 mm.
  • the heating power per area is greater in the first heating field region H1 than in the two second heating field regions H2 due to the shorter length of the first heating wires 7.1 compared to the second heating wires 7.2. According to the invention, this is to be avoided, which is explained below with reference to the following Figures 3 to 5.
  • Figure 3 shows a detailed section of an embodiment of the glazing 1 of Figure 1 in the area of the heating-wire-free zone 8 which is not claimed in the claims.
  • first heating wires 7.1 in the first heating field area H1 are all of the same design, i.e. are formed identically with respect to the described features.
  • second heating wires 7.2 in the two second heating field areas H2 are all of the same design, i.e. are formed identically with respect to the described features.
  • the first heating wires 7.1 in the first heating field region H1 and the second heating wires 7.2 in the two second heating field regions H2 differ in that the first heating wires 7.1 have a diameter that is smaller than the diameter of the second heating wires 7.2.
  • the electrical resistance of the first heating wires 7.1 can be increased compared to the electrical resistance of the second heating wires 7.2, so that a homogenization of the heating power per area of the entire heating field can be achieved.
  • Figure 4 shows, analogously to Figure 3, a detailed section of an embodiment of the glazing 1 of Figure 1 in the area of the heating-wire-free zone 8 which is not claimed in the claims.
  • the first heating wires 7.1 in the first heating field region H1 and the second heating wires 7.2 in the two second heating field regions H2 differ in this embodiment in that the first heating wires 7.1 have a larger distance between them than the second heating wires 7.2. This measure allows the heating power in the first heating field regions H1 to be reduced compared with the two second heating field regions H2, so that a homogenization of the heating power per area of the entire heating field can be achieved.
  • Figure 5 shows, analogously to Figure 3, a detailed section of an embodiment according to the invention of the glazing 1 of Figure 1 in the area of the heating-wire-free zone 8.
  • the first heating wires 7.1 in the first heating field region H1 and the second heating wires 7.2 in the two second heating field regions H2 differ in this embodiment in that the first heating wires 7.1 have a greater waviness than the second heating wires 7.2.
  • the heating power in the first heating field region H1 can be reduced compared to the two second heating field regions H2 due to an extension of the length of the first heating wires 7.1 compared to the second heating wires 7.2, so that a homogenization of the heating power per area of the entire heating field can be achieved.
  • FIG. 6 shows a flow diagram for the manufacturing of the glazing according to the invention, which comprises steps S1 to S3:
  • the second collecting conductor 6 is smaller than a shortest distance between at least one second collecting conductor section 5.2 of the first collecting conductor 5 and the second collecting conductor 6, first heating wires 7.1 extending from the first collecting conductor section
  • step S3) forming electric heating wires 7 wherein a waviness of the first heating wires 7.1 is greater than a waviness of the second heating wires 7.2.
  • the electrical resistance of the first heating wires in the first heating field region is greater than an electrical resistance of the second heating wires in the at least one second heating field region and/or a distance between immediately adjacent first heating wires in the first heating field region is greater than a distance between immediately adjacent second heating wires in the at least one second heating field region.
  • All the features of step S3) are configured such that a heating power per area in the first heating field region H1 corresponds to a heating power per area in the at least one second heating field region H2.
  • the method comprises a step of laminating the two panes
  • thermoplastic layer 4 by means of at least one thermoplastic layer 4.
  • the invention provides an improved glazing with a heating field, whereby a homogeneous heating power can be achieved in the entire heating field in an advantageous manner.
  • the glazing according to the invention can be produced simply and inexpensively using known manufacturing processes.

Landscapes

  • Surface Heating Bodies (AREA)

Abstract

The present invention relates to a glazing (1) with an electric heating field (H1, H2), which comprises: - 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 each other by electric heating wires (7) in such a way that an electric heating field (H1, H2) is formed between the two collecting conductors (5, 6), - at least one heating-wire-free zone (8) outside the heating field (H1, H2), wherein a first collecting conductor section (5.1) of the first collecting conductor (5) is guided around the heating-wire-free zone (8) in such a way that a shortest distance between the first collecting conductor section (5.1) and the second collecting conductor (6) is smaller than a shortest distance between at least one second collecting conductor section (5.2) of the first collecting conductor (5) and the second collecting conductor (6), first heating wires (7.1) extending from the first collecting conductor section (5.1) to the second collecting conductor (6) in a first heating field region (H1) and second heating wires (7.2) extending from the at least one second collecting conductor section (5.2) to the second collecting conductor (6) in a second heating field region (H2), wherein the heating wires (7.1, 7.2) have the following features i), ii) and/or iii): i) an electrical resistance of the first heating wires (7.1) is greater than an electrical resistance of the second heating wires (7.2), ii) a distance between immediately adjacent first heating wires (7.1) is greater than a distance between immediately adjacent second heating wires (7.2), iii) a waviness of the first heating wires (7.1) is greater than a waviness of the second heating wires (7.2), wherein features i), ii) and/or iii) are configured such that a heating power per area in the first heating field region (H1) corresponds to a heating power per area in the at least one second heating field region (H2).

Description

Glazing with electric heating field
The invention is in the technical field of glazing manufacture and relates to a glazing with an electric heating field, a method for its manufacture and its use.
The field of vision of a vehicle window, especially of a windshield, must be kept free of ice and fogging. In motor vehicles with internal combustion engines, for example, a stream of air heated by engine heat can be directed onto the windows.
In addition, the pane can have an electrical heating function, whereby a heating field is formed by electrically heatable structures. Composite panes are known, for example, which have a transparent, electrically conductive coating on an inner surface of one of the individual panes. An external voltage source can be used to conduct an electric current through the electrically conductive coating, which heats the coating and thus the pane. WO2012/052315 A1 discloses, for example, such a heatable metal-based coating. Also known is the use of electrically heatable metal wires, which are usually embedded in the thermoplastic interlayer in composite panes.
The electrical contacting of the electrically heatable structures is typically made via collecting conductors (busbars), as known for example from US 2007/0020465 A1. The collecting conductors consist, for example, of a printed and baked-on silver paste. The collecting conductors typically run along the top and bottom edges of the pane. The collecting conductors collect current flowing through the electrically heatable structures and conduct it to external leads connected to a voltage source.
Panes with electrically heatable structures shield electromagnetic radiation relatively strongly, so that radio data communications can be significantly impaired, especially in motor vehicles with an electrically heatable windshield. Electrically heatable windshields are therefore often provided with zones ("communication windows") in which the electrically heatable structures are not formed. These communication windows are well permeable at least for certain ranges of the electromagnetic spectrum and in this way enable smooth data traffic through the pane. The communication windows, where electronic devices such as sensors, cameras and the like can be located, are often arranged near the upper edge of the pane, where they can be well concealed by an upper masking strip.
However, communication windows, due to their spatial extension, affect the heating properties of the electrically heatable structures, which, at least locally, affects the heating power per area. In fact, they cause a highly inhomogeneous heating power distribution, with the heating power below and in the vicinity of the communication windows being significantly altered. As a result, very different pane temperatures can occur, imposing large thermal stresses on the panes. In addition, adhesion points of add-on parts can become detached as a result.
In general, it would be desirable to have a heatable glazing with an electric heating field that has at least an approximately homogeneous heat output (heating power) per area across the heating field.
DE 1 1 2018 004604 T5 discloses a glazing according to the preamble of claim 1 . JP H0872674 A dislocses a pane having electric heating wires that may vary in diameter and/or inter-distance.
In contrast, the object of the present invention is to provide an improved glazing with an electric heating field with which these disadvantages can be avoided. The glazing should be easy and inexpensive to manufacture in industrial series production.
These and further objects are solved according to the proposal of the invention by a glazing with an electric heating field according to the independent claim. Advantageous embodiments of the invention result from the subclaims.
According to the invention, an electrically heatable glazing with an electric heating field is shown, which typically, but not necessarily, serves to separate an interior from an external environment.
The glazing according to the invention can in principle be of any design, in particular as insulating glazing in which at least two panes are spaced apart by at least one spacer, as thermally toughened single-pane safety glass or as laminated pane. Preferably, the glazing according to the invention is designed as a laminated pane and comprises a first pane having an outer side and an inner side and a second pane having an inner side and an outer side, which are firmly bonded to one another by at least one thermoplastic intermediate layer (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 of the two individual panes are usually referred to as side I, side II, side III and side IV from the outside inwards.
The glazing according to the invention comprises at least one pane as well as a first collecting conductor and a second collecting conductor, which are provided for connection to a voltage source and are interconnected by a plurality of electric heating wires in such a way that an electric heating field is formed between the first collecting conductor and the second collecting conductor. The electrical heating wires are 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 connected directly to the two collecting conductors, the heating field being formed by the heating wires.
In the glazing according to the invention, at least one heating-wire-free zone is provided outside the heating field, which can serve in particular as a communication window. Advantageously, the heating-wire-free zone is arranged at an upper edge of the glazing, in particular at least approximately in the center of the pane. One or more sensors can be arranged at the heatingwire-free zone in the interior of, for example, a vehicle. The heating-wire-free zone does not have any heating wires, since these can negatively influence the passage of electromagnetic radiation through the zone, and thus the functionality of sensors. The heating-wire-free zone may have any suitable geometric shape, preferably the heating-wire-free zone is rectangular or trapezoidal in shape. Alternatively, an oval, circular, polygonal or any other suitable shape may be selected for the heating-wire-free zone.
According to the invention, a first collecting conductor section of the first collecting conductor is guided around the heating-wire-free zone in such a way that a shortest distance between the first collecting conductor section and the second collecting conductor is smaller than a shortest distance between at least one second collecting conductor section of the first collecting conductor and the second collecting conductor. Typically, the at least one second collecting conductor section is arranged adjacent to the first to the first collecting conductor section, wherein a second collecting conductor section may be arranged adjacent to each side of the first collecting conductor section, in which case the first collecting conductor is composed of a first collection conductor section and two second collecting conductor sections adjacent thereto.
First heating wires extend from the first collecting conductor section to the second collecting conductor, the first heating wires forming a first heating field region. Second heating wires extend from the at least one second collecting conductor section, in particular from two second collecting conductor sections, to the second collecting conductor, the second heating wires forming at least one second heating field region, in particular two second heating field regions. The heating wires are thus divided into or composed of the first heating wires and the second heating wires. The first heating wires are spatially separated from the second heating wires. Accordingly, the heating field is divided into or composed of a first heating field region (defined by the first heating wires) and at least one second heating field region (defined by the second heating wires), in particular two second heating field regions. The at least one second heating field region, in particular two second heating field regions, is or are spatially separated from the first heating field region.
According to the invention, the first heating wires in the first heating field region and the second heating wires in the at least one second heating field region are formed differently from each other. Stated more particularly, the first heating wires differ from the second heating wires in their waviness, with the waviness of the first heating wires in the first heating field region being greater than the waviness of the second heating wires in the at least one second heating field region.
It is essential here that the waviness of the heating wires is designed in such a way that a heating power per area (pane area) in the first heating field region corresponds to a heating power per area (pane area) in the at least one second heating field region.
The present invention is based on the insight that, due to a shorter distance between the two collecting conductors in that section of the first collecting conductor which is routed around the heating-wire-free zone, an increase in the heating power per area occurs in comparison to the rest of the heating field due to a reduction in the length of the otherwise identically formed heating wires and a thus resulting reduction in the length-dependent electrical resistance of the heating wires (resistance per length, as measured in ohms/m). This leads to an undesirable inhomogeneous heating power per area in the entire heating field. According to the invention, a homogenization of the heating power per area in the entire heating field can be achieved in an advantageous manner by modifying the waviness of the heating wires. In this way, the disadvantages mentioned at the beginning can be avoided, whereby in particular large thermal stresses do not occur on the pane. The heating wire-free zone can thus be suitably formed in size, shape and position according to its function, for example as a communication window, without taking into account any thermal inhomogeneities. These are major advantages of the invention.
In the glazing according to the invention, the heating field is formed by the electric heating wires extending between the first collecting conductor and the second collecting conductor, the two collecting conductors being electrically connected by the heating wires. 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 a waviness of the first heating wires in the first heating field region is greater than a waviness of the second heating wires in the at least one second heating field region.
In the sense of the present invention, a heating wire is regarded as "wavy", i.e. provided with waviness, if it has an undulating, in particular meandering (for example sinusoidal), course along its extension. Basically, a wavy heating wire extends along a (e.g. linear) direction of extension and exhibits wavy deflections perpendicular to the direction of extension. The length of the wavy heating wire measured along its extension direction (without taking into account the wavy deflections) is inevitably shorter than the actual length of the heating wire taking into account the deflections.
The waviness of a heating wire can be determined in a simple manner by stretching a wavy heating wire into a straight-line form, whereby the waviness can be described by a relative value as given by the length of the stretched (previously wavy) heating wire and the length of the (nonstretched) wavy heating wire along its direction of extension without taking wavy deflections into account. It is understood, that a same heating wire is considered for determining the waviness of the heating wire. If, for example, the length of a wavy heating wire can be extended by 10% by stretching it into a straight-line form, this results in a relative value of 1.1 (length of straight-line heating wire after stretching / length of wavy heating wire along its stretching direction before stretching).
Heating wires used in a glazing according to the invention are provided with a waviness, i.e. they have an undulating course which differs from the straight-line course. The waviness of the heating wire changes its length and thus also the length-dependent electrical resistance of the heating wire (as measured in Ohm/m).
In principle, changing the length of a heating wire changes the length-dependent electrical resistance, with the length-dependent electrical resistance increasing as the length increases. Due to the greater waviness of 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 first heating wires are provided with such a waviness that each first heating wire is subject to an increase in length by a factor in the range 1.1 to 1.4 due to stretching. This measure makes it possible to achieve good homogenization of the heating power per area, particularly in the case of conventional vehicle glazing, such as a windshield with a heating-wire-free zone arranged at the upper edge of the pane.
According to further embodiments according to the invention, at least one of the following features i) and ii) is realized:
Feature i):
An electrical resistance of the first heating wires in the first heating field region is greater than an electrical resistance of the second heating wires in the at least one second heating field region.
Feature ii):
A distance between immediately adjacent first heating wires in the first heating field region is greater than a distance between immediately adjacent second heating wires in the at least one second heating field region.
It is essential here that features i) and/or ii) are designed in such a way that a heating power per area (pane area) in the first heating field region corresponds to a heating power per 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 an electrical resistance of the first heating wires in the first heating field region is greater than an electrical resistance of the second heating wires in the at least one second heating field region. Due to the higher electrical resistance of the first heating wires, the heating power per area in the first heating field area can be reduced in an advantageous manner compared to the heating power per region in the at least one second heating field region.
An increase in electrical resistance can in principle be achieved in any way, for example by choosing a material for the first heating wires that is different from the material of the second heating wires which has a higher electrical resistance. According to an advantageous embodiment of the glazing according to the invention, the material of the heating wires is the same and the diameter of the first heating wires in the first heating field region is smaller than the diameter of the second heating wires in the at least one second heating field region. By this measure, the electrical resistance of the heating wires can be selectively adjusted in a simple manner by dimensioning the diameter of the heating wires such that the electrical resistance thereof is increased, with the heating power per area decreasing as the diameter of the heating wires is increased, and vice versa.
Preferably, the diameter of the first heating wires in the first heating field region is 20% to 30%, in particular 25%, smaller than the diameter of the second heating wires in the at least one second heating field region, as a result of which good homogenization of the heating power per area can be achieved, in particular in the case of conventional vehicle glazing such as a windshield with a heating-wire-free zone arranged at the upper edge of the pane.
Advantageously, the diameter of the heating wires is from 10 pm to 200 pm, in particular from 15 pm to 35 pm and especially from 18 pm to 29 pm.
According to feature ii), the heating wires in the heating field are formed such that a distance between directly adjacent first heating wires in the first heating field region is greater than a distance between directly adjacent second heating wires in the at least one second heating field region. Due to the larger 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 a distance between directly adjacent second heating wires in the second heating field region. This measure makes it possible to achieve good homogenization of the heating power per area, particularly in the case of conventional vehicle glazing, such as a windshield with a heating-wire-free zone arranged at the upper edge of the pane.
Advantageously, the distance between directly adjacent heating wires in the heating field is in the range of 2 to 3 mm.
According to a further embodiment of the glazing according to the invention, the length-dependent electrical resistance of the heating wires is in the range of 100 to 220 Ohm/m. According to a further embodiment of the glazing according to the invention, the heating wires in the heating field have a length in the range of 50 to 200 cm depending on the height of the glazing.
The heating wires can be heated electrically and, for this purpose, consist of an electrically conductive material that can basically be selected as desired. Advantageously, the heating wires consist of a metallic material. Preferably, the heating wires contain or consist of aluminum, copper, tinned copper, gold, silver, zinc, tungsten and/or tin or alloys thereof, in particular copper and/or tungsten. The first heating wires may consist of a material that is the same as or different from the material of the second heating wires.
The at least one pane preferably contains or consists of 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. Suitable glasses are known, for example, from EP 0 847 965 B1 .
The thickness of the at least one pane can vary widely and be adapted to the requirements of the individual case. Preferably, panes with standard thicknesses of 1 .0 mm to 25 mm and preferably 1 .4 mm to 2.1 mm are used. The size of the panes can vary widely and depends on the use.
Particularly advantageously, the glazing according to the invention is in the form of a laminated pane and comprises a first pane and a second pane which are firmly connected to one another by at least one thermoplastic intermediate layer. The electrical heating wires are arranged between the two panes, preferably embedded in the thermoplastic intermediate layer. Advantageously, the heating wires are arranged adjacent to an inner surface (side III, side II) of the outer pane and inner pane, respectively.
The thermoplastic intermediate layer contains or consists of at least one thermoplastic, preferably polyvinyl butyral (PVB), ethylene vinyl acetate (EVA) and/or polyethylene terephthalate (PET). However, the thermoplastic interlayer may also include, for example, polyurethane (PU), polypropylene (PP), polyacrylate, polyethylene (PE), polycarbonate (PC), polymethyl metacrylate, polyvinyl chloride, polyacetate resin, casting resin, acrylate, fluorinated ethylenepropylene, polyvinyl fluoride and/or ethylene-tetrafluoroethylene, or a copolymer or mixture thereof. The thermoplastic interlayer can be formed by one or more thermoplastic films stacked on top of each other, and the thickness of a thermoplastic film is preferably from 0.6 mm to 1 .8 mm, typically 0.76 mm 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 direction or in multiple directions of space. The at least one pane may be colorless or colored.
The heating wires are electrically connected to two collecting conductors through which a (heating) current can be fed into the heating wires. The collecting conductors are preferably arranged in the edge region of the glazing along a side edge on a surface of the at least one pane. In a composite pane, the two collecting conductors are preferably arranged on an inner surface (side II or side III) thereof.
The width of a respective collecting conductor is preferably from 2 mm to 30 mm, particularly preferably from 4 mm to 20 mm. The collecting conductors are typically each in the form of a strip, the longer of its dimensions being referred to as the length and the less long of its dimensions being referred to as the width.
Collecting conductors are formed, for example, as printed and baked-on conductive structures. The printed collecting conductor contains at least one metal, preferably silver. The electrical conductivity is preferably realized via metal particles contained in the collecting conductor, particularly preferably via silver particles. The metal particles can be in an organic and/or inorganic matrix such as pastes or inks, preferably as fired screen printing paste with glass frits. The layer thickness of the imprinted collecting conductor is preferably from 5 pm to 40 pm, more preferably from 8 pm to 20 pm and most preferably from 10 pm to 15 pm. Printed collecting conductors with these thicknesses are technically easy to realize and have an advantageous current-carrying capacity. Alternatively, the collecting conductor can also be formed as a strip of electrically conductive film. The collecting conductor 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 10 pm to 500 pm, particularly preferably 30 pm to 300 pm. Collecting conductors made of electrically conductive films with these thicknesses are technically easy to realize and have an advantageous current-carrying capacity. The collecting conductors can be electrically conductively connected to the heating wires, for example, via a solder compound, via an electrically conductive adhesive or by direct application. The first collecting conductor and/or the second collection conductor may each comprise a plurality of non-contiguous parts. For the purpose of the present invention, the term "first collecting conductor" or "second collecting conductor" also includes a collecting conductor consisting of several non-contiguous parts, wherein the non-contiguous parts serve to be connected to a same pole of a voltage source or a same electrical potential.
Furthermore, the invention extends to a method of manufacturing a glazing according to the invention as-above desribed. The features described in connection with the glazing also apply to the claimed method. The method comprising the following steps:
51 ) providing at least one pane,
52) forming of a first collecting conductor and a second collecting conductor, the first collecting conductor comprising a first collecting conductor section and at least one second collecting conductor section;
53) forming electric heating wires, the heating wires comprising first heating wires and second heating wires, the electric heating field comprising a first heating field region and a second heating field region, wherein the first collecting conductor section of the first collecting conductor is guided around a heating-wire-free zone in such a way that a shortest distance between the first collecting conductor section and the second collecting conductor is smaller than a shortest distance between the at least one second collecting conductor section and the second collecting conductor, the first heating wires extending in the first heating field region from the first collecting conductor section to the second collecting conductor, and in the second heating field region second heating wires extending from the at least one second collecting conductor section to the second collecting conductor, characterized in that a waviness of the first heating wires is greater than a waviness of the second heating wires, with waviness being described by a relative value as given by the length of a stretched, previously wavy, heating wire and the length of the, non-stretched, wavy heating wire along its direction of extension without taking wavy deflections into account, wherein the waviness of the heating wires is configured such that a heating power per area in the first heating field region corresponds to a heating power per area in the second heating field region.
Preferably, the glazing according to the invention is manufactured in the form of a laminated pane (composite pane). For the production of a laminated pane, at least two panes are preferably bonded (laminated) to one another under the action of heat, vacuum and/or pressure by means of at least one thermoplastic adhesive layer. Processes known per se can be used to produce a laminated pane. For example, so-called autoclave processes can be carried out at an elevated pressure of about 10 bar to 15 bar and temperatures of 130 °C to 145 °C for about 2 hours. Vacuum bag or vacuum ring processes known per se operate, for example, at 90 °C to 120 °C and vacuum level of 0.8 to 0.99 bar. The two panes and the thermoplastic intermediate layer can also be pressed in a calender between at least one pair of rolls to form a composite pane. Plants of this type are known for the production of composite panes and usually have at least one heating tunnel upstream of a pressing unit. The temperature during the pressing process ranges, for example, from 45 °C to 100 °C. Combinations of calender and autoclave processes have proved particularly effective in practice. Alternatively, vacuum laminators can be used. These consist of one or more chambers which can be heated and evacuated and in which the first pane and second pane can be laminated within, for example, about 60 minutes at reduced pressures of 0.01 mbar to 800 mbar and temperatures of 80°C to 170°C. The first pane and the second pane are then laminated in a vacuum laminator.
The heating wires are preferably embedded in the thermoplastic intermediate layer at side II and/or side III of the panes. The heating wires are typically applied using an application drum. In this process, a respective heating wire is moved with an application head and unwound from a spool, and, in particular, can be provided with waviness. 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 is to penetrate fully or partially into the surface of the thermoplastic interlayer so that it is embedded in the interlayer. In the laminated composite pane, the heating wires are arranged between the two panes, in particular, for example, adjacent to the first pane or adjacent to the second pane. Heating wires having different waviness in the first and second heating field regions can readily, fast and very economically be made by using such application head. This is an important advantage of the present invention.
Furthermore, the invention extends to the use of the glazing according to the invention on buildings or in means of transport for traffic on land, in the air or on water, in particular in motor vehicles, for example as a windshield, rear window, side windows and/or roof window. According to the invention, the use of the glazing in motor vehicles is preferred.
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 combinations indicated, but also in other combinations or alone, without leaving the scope of the present invention.
The invention is explained in more detail below by means of embodiments with reference to the accompanying figures. They show in simplified, not to scale representation:
Fig. 1 a top view of an embodiment of the glazing according to the invention, which is in the form of a laminated pane,
Fig. 2 a cross-sectional view of the composite pane of Fig. 1 ,
Fig. 3 a top view of an embodiment of the composite pane of Fig. 1 ,
Fig. 4 a top view of a further embodiment of the composite pane of Fig. 1 ,
Fig. 5 a top view of a further embodiment of the composite pane of Fig. 1 ,
Fig. 6 a flow chart illustrating the process of manufacturing a glazing according to the invention.
Let figures 1 and 2 be considered first. Figure 1 shows a top view of an embodiment of the glazing 1 according to the invention in a simplified, schematic representation. A cross-sectional view of the glazing 1 of Figure 1 is shown in Figure 2.
The glazing 1 is in the form of a laminated pane and comprises a first pane 2 (e.g. outer pane) and a second pane 3 (e.g. inner pane), which are firmly connected to one another by a thermoplastic intermediate layer 4. Heating wires 7 are embedded in the thermoplastic intermediate layer 4, here for example adjacent to the inner surface (side III) of the second pane 3 (see Figure 2). The glazing 1 can be installed in a building or motor vehicle and separates an interior space from an external environment. For example, the glazing is the windshield of a motor vehicle. Alternatively, the glazing has only a single pane, preferably in the form of a thermally toughened single-pane safety glass (not shown).
The first pane 2 and the second pane 3 are each made of glass, preferably thermally toughened soda-lime glass, and are transparent to visible light. The thermoplastic intermediate layer 4 consists of a thermoplastic, 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. The inner surface II of the first pane 2 and the outer surface III of the second pane 3 each face the intermediate layer 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 is understood that the glazing 1 may have any suitable geometric shape 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 center, there is a heating-wire-free zone 8, here for example rectangular in shape. The glazing 1 has a first collecting conductor 5 at the upper edge and a second collecting conductor 6 at the lower edge. The relative indications "upper" and "lower" refer to the typical installation state of the glazing 1 , for example as a windshield. The two collecting conductors 5, 6 are electrically conductively connected to each other by heating wires 7, the heating wires 7 extending from the first collecting conductor 5 to the second collecting conductor 6. An electric heating field is formed by the electric heating wires 7. The heating wires each extend at least approximately perpendicular to the collecting conductors 5, 6.
The first collecting conductor 5 is routed around the heating-wire-free zone 8 in a first collecting conductor section 5.1 , which here, for example, serves as a communication window. Here, the first collecting conductor section 5.1 is routed around the heating-wire-free zone 8 below the heating-wire-free zone 8. Adjacent to the first collecting conductor section 5.1 are two second collecting conductor sections 5.2, which are not routed around the heating-wire-free zone 8. The first collecting conductor 5 is composed of the first collecting conductor section 5.1 and the two second collecting conductor sections 5.2. The shortest (here vertical) distance between the first collecting conductor section 5.1 and the second collecting conductor 6 is less than the shortest (here vertical) distance between each second collecting conductor section 5.2 and the second collecting conductor 6.
The first collecting conductor section 5.1 and the second collecting conductor 6 are electrically connected to each other by first heating wires 7.1 , the first heating wires 7.1 extending from the first collecting conductor section 5.1 to the second collecting conductor 6. The first heating wires 7.1 form a first heating field region H1 . The two second collection conductor sections 5.2 and the second collecting conductor 6 are electrically connected to each other by second heating wires 7.2, the second heating wires 7.2 extending from the two second collecting conductor sections 5.2 to the second collecting conductor 6. The second heating wires 7.2 form two second heating field regions H2. The heating field is composed of the first heating field region H1 and the two second heating field regions H2.
The two collecting conductors 5, 6 are used to be connected to an electrical voltage source in order to feed the heating wires 7 with electrical current and to electrically heat the glazing 1 .
While not shown in Figure 1 , the first collecting conductor 5 and the second collecting conductor 6 may each consist of two or more non-contiguous parts, wherein the two or more non-contiguous parts of the first collecting conductor 5 serve to be connected to a first pole of a voltage source or a first electrical potential and the two or more non-contiguous parts of the second collecting conductor 6 serve to be connected to a second pole of the voltage source or a second electrical potential (different from the first electrical potential). For example, both the first collecting conductor 5 and the second collecting conductor 6 may each consist of two non-contiguous parts so that the heating field is divided into two separate portions, e.g. two at least approximately symmetrical portions which are separated by a non-heated region, e.g. in a middle position of the glazing 1 . For example, the non-heated region, e.g. in a middle position, has a width (as 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 in the second heating field regions H2 are of the same design except for their length, the heating power per area (pane area) is greater in the first heating field region H1 than in the two second heating field regions H2 due to the shorter length of the first heating wires 7.1 compared to the second heating wires 7.2. According to the invention, this is to be avoided, which is explained below with reference to the following Figures 3 to 5.
Figure 3 shows a detailed section of an embodiment of the glazing 1 of Figure 1 in the area of the heating-wire-free zone 8 which is not claimed in the claims. Although only a section of the glazing 1 of Figure 1 is shown in Figure 3, it is understood that the first heating wires 7.1 in the first heating field area H1 are all of the same design, i.e. are formed identically with respect to the described features. In a corresponding manner, the second heating wires 7.2 in the two second heating field areas H2 are all of the same design, i.e. are formed identically with respect to the described features. The first heating wires 7.1 in the first heating field region H1 and the second heating wires 7.2 in the two second heating field regions H2 differ in that the first heating wires 7.1 have a diameter that is smaller than the diameter of the second heating wires 7.2. By this measure, the electrical resistance of the first heating wires 7.1 can be increased compared to the electrical resistance of the second heating wires 7.2, so that a homogenization of the heating power per area of the entire heating field can be achieved.
Figure 4 shows, analogously to Figure 3, a detailed section of an embodiment of the glazing 1 of Figure 1 in the area of the heating-wire-free zone 8 which is not claimed in the claims. The first heating wires 7.1 in the first heating field region H1 and the second heating wires 7.2 in the two second heating field regions H2 differ in this embodiment in that the first heating wires 7.1 have a larger distance between them than the second heating wires 7.2. This measure allows the heating power in the first heating field regions H1 to be reduced compared with the two second heating field regions H2, so that a homogenization of the heating power per area of the entire heating field can be achieved.
Figure 5 shows, analogously to Figure 3, a detailed section of an embodiment according to the invention of the glazing 1 of Figure 1 in the area of the heating-wire-free zone 8. The first heating wires 7.1 in the first heating field region H1 and the second heating wires 7.2 in the two second heating field regions H2 differ in this embodiment in that the first heating wires 7.1 have a greater waviness than the second heating wires 7.2. As a result of this measure, the heating power in the first heating field region H1 can be reduced compared to the two second heating field regions H2 due to an extension of the length of the first heating wires 7.1 compared to the second heating wires 7.2, so that a homogenization of the heating power per area of the entire heating field can be achieved.
The embodiments of the glazing according to the invention illustrated by means of Figures 3 to 5 may be provided alone or in any combination.
Figure 6 shows a flow diagram for the manufacturing of the glazing according to the invention, which comprises steps S1 to S3:
51 ) providing at least one pane 2, 3,
52) forming a first collecting conductor 5 and a second collecting conductor 6, wherein a first collecting conductor section 5.1 of the first collecting conductor 5 is guided around a heating-wire- free zone 8 in such a way that a shortest distance between the first collecting conductor section
5.1 and the second collecting conductor 6 is smaller than a shortest distance between at least one second collecting conductor section 5.2 of the first collecting conductor 5 and the second collecting conductor 6, first heating wires 7.1 extending from the first collecting conductor section
5.1 to the second collecting conductor 6 in a first heating field region H1 and second heating wires
7.2 extending from the at least one second collecting conductor section 5.2 to the second collecting conductor 6 in a second heating field region H2,
S3) forming electric heating wires 7 wherein a waviness of the first heating wires 7.1 is greater than a waviness of the second heating wires 7.2. Optionally, the electrical resistance of the first heating wires in the first heating field region is greater than an electrical resistance of the second heating wires in the at least one second heating field region and/or a distance between immediately adjacent first heating wires in the first heating field region is greater than a distance between immediately adjacent second heating wires in the at least one second heating field region. All the features of step S3) are configured such that a heating power per area in the first heating field region H1 corresponds to a heating power per area in the at least one second heating field region H2.
In the manufacture of a composite pane, the method comprises a step of laminating the two panes
2.3 by means of at least one thermoplastic layer 4.
It follows from the above that the invention provides an improved glazing with a heating field, whereby a homogeneous heating power can be achieved in the entire heating field in an advantageous manner. The glazing according to the invention can be produced simply and inexpensively using known manufacturing processes.
List of reference signs
1 glazing
2 first pane 3 second pane
4 thermoplastic interlayer
5 first collecting conductor
5.1 first collecting conductor section
5.2 second collecting conductor section 6 second collecting conductor
7 heating wires
7.1 first heating wires in the first heating field region H1
7.2 second heating wires in the second heating field region H2
8 heating-wire-free zone H1 first heating field region
H2 second heating field region

Claims

Claims
1 . Glazing (1 ) with an electric heating field (H1 , H2), which comprises: 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 each other by electric heating wires (7) in such a way that an electric heating field (H1 , H2) is formed between the two collecting conductors (5, 6), with the heating wires (7) comprising first heating wires (7.1 ) and second heating wires (7.2), the electric heating field (H1 , H2) comprising a first heating field region (H1 ) and a second heating field region (H2), and the first collecting coductor (5) comprising a first collecting conductor section (5.1 ) and at least one second collecting conductor section (5.2), at least one heating-wire-free zone (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 heating-wire-free zone (8) in such a way that a shortest distance between the first collecting conductor section (5.1 ) and the second collecting conductor (6) is smaller than a shortest distance between the at least one second collecting conductor section (5.2) of the first collecting conductor (5) and the second collecting conductor (6), the first heating wires (7.1 ) extending from the first collecting conductor section (5.1 ) to the second collecting conductor (6) in the first heating field region (H1 ), the second heating wires (7.2) extending from the at least one second collecting conductor section (5.2) to the second collecting conductor (6) in the second heating field region (H2), characterised in that a waviness of the first heating wires (7.1 ) is greater than a waviness of the second heating wires (7.2), with waviness being described by a relative value as given by the length of a stretched, previously wavy, heating wire and the length of the, non-stretched, wavy heating wire along its direction of extension without taking wavy deflections into account, wherein the waviness of the heating wires (7.1 , 7.2) is configured such that a heating power per area in the first heating field region (H1 ) corresponds to a heating power per area in the second heating field region (H2).
2. Glazing (1 ) according to claim 1 , in which the first heating wires (7.1 ) have a waviness that is 20% to 30%, in particular 25%, greater than a waviness of the second heating wires (7.2).
3. Glazing (1 ) according to claim 2, in which a waviness of the heating wires (7) is formed such that a wavy heating wire (7) is subject to an increase in length by a factor in the range 1 .1 to 1.4 due to stretching.
4. Glazing (1 ) according to any one of claims 1 to 3, in which wherein the heating wires (7.1 , 7.2) have at least one of the following features i) and ii): i) an electrical resistance of the first heating wires (7.1 ) is greater than an electrical resistance of the second heating wires (7.2), in particular, wherein a diameter of the first heating wires (7.1 ) is smaller than a diameter of the second heating wires (7.2), ii) a distance between immediately adjacent first heating wires (7.1 ) is greater than a distance between immediately adjacent second heating wires (7.2), wherein features i) and/or ii) are configured such that a heating power per area in the first heating field region (H1 ) corresponds to a heating power per area in the at least one second heating field region (H2).
5. Glazing (1 ) according to claim 4, feature i), in which the diameter of the first heating wires
(7.1 ) is 20% to 30%, in particular 25%, smaller than the diameter of the second heating wires
(7.2), wherein the diameter of the heating wires (7) in particular is from 10 pm to 200 pm, in particular from 15 pm to 35 pm, and in particular from 18 pm to 29 pm.
6. Glazing (1 ) according to claim 4, feature ii), an claim 5, in which the spacing of directly adjacent first heating wires (7.1 ) is greater by 20% to 30%, in particular 25%, than the spacing of directly adjacent second heating wires (7.2), wherein a spacing of directly adjacent heating wires (7) in the heating field (H1 , H2) in particular is in the range of 2 to 3 mm
7. Glazing (1 ) according to any one of claims 1 to 6, in which the first collecting conductor (5) comprises a plurality of non-contiguous parts which are to be connected to a same pole of a voltage source or a same electrical potential.
8. Glazing (1 ) according to any one of claims 1 to 7, in which the second collecting conductor (6) comprises a plurality of non-contiguous parts which are to be connected to a same pole of a voltage source or a same electrical potential.
9. Glazing (1 ) according to any one of claims 1 to 8, in which an electrical linear resistance of the heating wires (7) is in the range from 100 to 220 ohm/m.
10. Glazing (1 ) according to any one of claims 1 to 9, in which the heating wires (7) have a length in the range from 70 to 90 cm.
11 . Glazing (1 ) according to any one of claims 1 to 10, wherein the heating wires (7) comprise or consist of aluminum, copper, tinned copper, gold, silver, zinc, tungsten and/or tin or alloys thereof, in particular copper and/or tungsten.
12. Glazing according to any one of claims 1 to 1 1 , in which the at least one pane (2, 3) comprises or consists of glass, in particular soda-lime glass, or plastics, in particular preferably rigid plastics, in particular polycarbonate, or polymethyl methacrylate.
13. Glazing according to any one of claims 1 to 12, which is in the form of a laminated pane, comprising a first pane (2) and a second pane (3) which are connected to one another by at least one thermoplastic intermediate layer (4), the electric heating wires (7) being arranged between the two panes (1 , 2), in particular being embedded in the thermoplastic intermediate layer (4).
14. Method of manufacturing a glazing (1 ) with electric heating field (1 HH1 , H2), in particular a laminated pane, according to any one of claims 1 to 13, comprising the following steps:
51 ) providing at least one pane (2, 3),
52) forming of a first collecting conductor (5) and a second collecting conductor (6), the first collecting conductor comprising a first collecting conductor section (5.1 ) and at least one second collecting conductor section (5.2);
53) forming electric heating wires (7), the heating wires (7) comprising first heating wires (7.1 ) and second heating wires (7.2), the electric heating field comprising a first heating field region (H1 ) and a second heating field region (H2), wherein the first collecting conductor section (5.1 ) of the first collecting conductor (5) is guided around a heating-wire-free zone (8) in such a way that a shortest distance between the first collecting conductor section (5.1 ) and the second collecting conductor (6) is smaller than a shortest distance between the at least one second collecting conductor section (5.2) and the second collecting conductor (6), the first heating wires (7.1 ) extending in the first heating field region (H1 ) from the first collecting conductor section (5.1 ) to the second collecting conductor (6), and in the second heating field region (H2) second heating wires (7.2) extending from the at least one second collecting conductor section (5.2) to the second collecting conductor (6), characterized in that a waviness of the first heating wires (7.1 ) is greater than a waviness of the second heating wires (7.2), with waviness being described by a relative value as given by the length of a stretched, previously wavy, heating wire and the length of the, non-stretched, wavy heating wire along its direction of extension without taking wavy deflections into account, 21 wherein the waviness of the heating wires (7) is configured such that a heating power per area in the first heating field region (H1 ) corresponds to a heating power per area in the second heating field region (H2).
15. Use of the glazing (1 ) according to any of claims 1 to 13 on buildings, in means of transport for traffic on land, in the air or on water, in particular in motor vehicles, for example as a windshield, rear window, side window and/or roof window.
EP22702616.8A 2021-01-18 2022-01-17 Glazing with electric heating field Pending EP4278861A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP21151976 2021-01-18
PCT/EP2022/050912 WO2022152910A1 (en) 2021-01-18 2022-01-17 Glazing with electric heating field

Publications (1)

Publication Number Publication Date
EP4278861A1 true EP4278861A1 (en) 2023-11-22

Family

ID=74186572

Family Applications (1)

Application Number Title Priority Date Filing Date
EP22702616.8A Pending EP4278861A1 (en) 2021-01-18 2022-01-17 Glazing with electric heating field

Country Status (3)

Country Link
EP (1) EP4278861A1 (en)
CN (1) CN115119542A (en)
WO (1) WO2022152910A1 (en)

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0872674A (en) 1994-07-08 1996-03-19 Asahi Glass Co Ltd Electrically heated windowpane
FR2757151B1 (en) 1996-12-12 1999-01-08 Saint Gobain Vitrage GLAZING COMPRISING A SUBSTRATE PROVIDED WITH A STACK OF THIN FILMS FOR SUN PROTECTION AND / OR THERMAL INSULATION
US6559419B1 (en) * 2001-08-03 2003-05-06 Centre Luxembourgeois De Recherches Pour Le Verre Et La Ceramique S.A. (C.R.V.C.) Multi-zone arrangement for heatable vehicle window
GB0427749D0 (en) * 2004-12-18 2005-01-19 Pilkington Plc Electrically heated window
US7335421B2 (en) 2005-07-20 2008-02-26 Ppg Industries Ohio, Inc. Heatable windshield
DE102007001080A1 (en) * 2007-01-04 2008-07-10 Saint-Gobain Sekurit Deutschland Gmbh & Co. Kg Electrically heated window pane
EP2444381A1 (en) 2010-10-19 2012-04-25 Saint-Gobain Glass France Transparent glazing
WO2019078258A1 (en) 2017-10-20 2019-04-25 Ａｇｃ株式会社 Laminated glass for vehicle

Also Published As

Publication number Publication date
CN115119542A (en) 2022-09-27
WO2022152910A1 (en) 2022-07-21

Similar Documents

Publication Publication Date Title
US10728959B2 (en) Pane having an electric heating layer
US7205504B2 (en) Interlayer composite for a laminated transparency
US20190141792A1 (en) Pane having an electric heating layer
CA2491707C (en) Eliminating hot spots at end portions of bus bars of a heatable transparency having an electrically conductive member
JP6351826B2 (en) Transparent window plate with electric heating layer, method for manufacturing transparent window plate and use of transparent window plate
US10638550B2 (en) Pane with an electrical heating region
JP6381780B2 (en) Transparent window plate with electric heating layer, method for manufacturing transparent window plate and use of transparent window plate
US10694586B2 (en) Transparent pane having a heatable coating
CA2942938C (en) Transparent pane with heatable coating
EP4278861A1 (en) Glazing with electric heating field
CN113767010A (en) Method for manufacturing composite glass plate with electrically controllable optical properties

Legal Events

Date Code Title Description
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: UNKNOWN

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE INTERNATIONAL PUBLICATION HAS BEEN MADE

PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE

17P Request for examination filed

Effective date: 20230830

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

DAV Request for validation of the european patent (deleted)
DAX Request for extension of the european patent (deleted)