Composite pane with segment-like switchable functional element with electrically controllable optical properties

Description

[0001] The invention relates to a composite pane with a segment-like switchable functional element with electrically controllable optical properties, a method for its production and its use.

[0002] To protect the driver and other passengers from glare, conventional motor vehicles are equipped with mechanical sun visors. These are mounted on the vehicle roof and can be folded down when needed to prevent or at least reduce the glare on the driver or passenger, for example, from a low sun.

[0003] Windshields are also known in which a sun visor is integrated in the form of a functional element with electrically adjustable optical properties, particularly with electrically adjustable transmission or scattering behavior. This allows the driver to control the windshield's transmission behavior with respect to solar radiation, making the conventional mechanical sun visor unnecessary. This reduces the vehicle's weight and frees up space in the roof area. Furthermore, electrically adjusting the sun visor is more convenient for the driver than manually folding down the mechanical sun visor.

[0004] Electrically adjustable sun visors are also used in the glass roofs of motor vehicles. Especially with large panoramic glass panes, there is a need to variably control the transmission of the pane. Depending on the position of the sun, it may be necessary to dim only certain sections of the pane, or to make the entire surface opaque as a privacy screen in a parked vehicle.

[0005] A possible electrically switchable functional element for the realization of adjustable sun visors is a so-called PDLC functional element ( polymer dispersed liquid crystalThe active layer contains liquid crystals embedded in a polymer matrix. If no voltage is applied, the liquid crystals are randomly aligned, which leads to strong scattering of the light passing through the active layer. If a voltage is applied to the surface electrodes, the liquid crystals align in a common direction, and the transmission of light through the active layer is increased. The PDLC functional element works less by reducing the overall transmission than by increasing the scattering to ensure glare protection.

[0006] Windshields with electrically adjustable sun visors are known, for example, from DE 102013001334 A1, DE 102005049081 B3, DE 102005007427 A1, and DE 102007027296 A1. DE 102010021563 A1 describes a windshield with an electrically adjustable sun visor that can be switched on and off in certain areas, with the dimming of the individual elements being controlled via a capacitive sensor arrangement in the edge area of ​​the sun visor.

[0007] Electrical contacting of electrically controllable functional elements is typically achieved via bus bars, which are applied to the surface electrodes at the edge of the functional element and form an electrically conductive contact. By connecting the bus bars to an external voltage source, for example, via flat conductors attached to the bus bars, a voltage is applied to the surface electrodes and the active layer of the functional element is switched. Particularly with small, individually switchable segments, it is difficult to ensure homogeneous switching behavior with the lowest possible operating voltages and a long service life of the electrical contact. As the size of the element to be switched decreases, the area available for electrically contacting the surface electrodes with the bus bars also decreases.A certain inhomogeneity of the surface electrodes in the area of ​​the contacting surface can be problematic, especially with small contacting surfaces. Inhomogeneities in the surface electrodes occur, for example, due to minor damage when exposing the electrically conductive layers for subsequent contacting. Such damage can be triggered by the particles of the active layer itself. The crystals contained in a PDLC layer are enough to scratch the surface electrode when the PDLC layer on the surface electrode is removed. These scratches result in a locally increased power consumption, a resulting heating, and ultimately in the failure of the component. In the case of large-area bus bars, the damaged portion of the contacting surface is quite small compared to the total area.However, as bus bars become smaller, the proportion of damaged contact area increases, resulting in increased component failure.

[0008] US 2016 / 0306249 A1 discloses an insulating glazing comprising an electrochromic element comprising a plurality of electrically independently switchable regions.

[0009] WO 2017 / 157626 A1 discloses a windshield with a PDLC functional element, wherein the PDLC functional element can be switched segment by segment.

[0010] US 2002 / 0044331 A1 discloses a substrate with an electrochromic element, wherein the surface electrodes of the electrochromic element are provided with bus bars along their circumference.

[0011] The object of the present invention is to provide a composite pane with a segment-like switchable functional element with electrically controllable optical properties, which has improved electrical contact with increased service life and homogeneous switching behavior.

[0012] The object of the present invention is achieved by a composite pane with a segment-like switchable functional element with electrically controllable optical properties according to independent claim 1. Preferred embodiments are evident from the subclaims.

[0013] The composite pane according to the invention contains a segment-like switchable functional element with electrically controllable optical properties, the optical properties of which can be regulated as a function of the applied voltage. The functional element is embedded in the intermediate layer of the composite pane. The intermediate layer connects the first pane and the second pane of the composite pane. The controllable functional element comprises an active layer between a first surface electrode and a second surface electrode. The surface electrodes and the active layer are arranged one above the other in a planar manner. The active layer has the controllable optical properties, which can be controlled via the voltage applied to the surface electrodes. The surface electrodes and the active layer are typically arranged essentially parallel to the surfaces of the first pane and the second pane.The surface electrodes are electrically connected to bus bars, via which the functional element can be connected to an external voltage source. In order to be able to switch the functional element section by section, in the form of individual segments, these must be individually electrically controllable. For this purpose, the first surface electrode is divided into several segments by means of at least one dividing line. The dividing line can also be referred to as an insulation line and effects an electrical separation of the individual segments of the first surface electrode from one another. A group of first bus bars is used to make electrical contact with the first surface electrode, with each segment of the first surface electrode being contacted by at least two bus bars from the group of first bus bars. The second surface electrode is electrically contacted by at least one second bus bar.The first surface electrode is connected to one pole of the voltage source via the group of first bus bars, and the second surface electrode is connected to the opposite pole of the voltage source via at least the second bus bar. Depending on the type of functional element, the voltage source can be configured as an AC voltage source or a DC voltage source.

[0014] For the purposes of the invention, a separating line is understood to be a linear region within the surface electrode which is not electrically conductive and which extends over the entire thickness of the surface electrode.

[0015] The inventive design of the composite pane allows the active layer to be selectively switched in sections, with the selectively switchable regions of the active layer corresponding to a projection of the segments of the first surface electrode onto the active layer. For targeted control of the segments, the opposing poles of a voltage source are connected to the bus bars of the first surface electrode and the second surface electrode, depending on the desired circuit pattern of the active layer. One pole of the voltage source is connected to the second bus bar(s) of the second surface electrode, while the opposite pole of the voltage source is connected to the first bus bars that are contacted in the region of the segments of the first surface electrode to be controlled.An electrical potential difference between the surface electrodes therefore only exists in those areas of the functional element where the corresponding segments of the first surface electrode are connected to the voltage source. Accordingly, the active layer of the functional element is only switched in these areas. The dividing lines between the individual segments of the first surface electrode ensure that no current flows through other segments of the coating. The targeted control of the segments of the first surface electrode to which a voltage is to be applied is achieved, for example, via an external control unit.

[0016] Because each segment of the first surface electrode is electrically contacted by at least two of the first bus bars according to the invention, the reliability of the functional element can be significantly improved and the risk of failure of the glazing can be minimized. In particular with short bus bars, as is generally the case with segment-like switchable functional elements, the risk of failure of a bus bar due to overheating is increased. By using at least two bus bars, this problem can be remedied, since even if one bus bar is defective, another bus bar is available to switch the relevant segment. Furthermore, the inventors were surprisingly able to determine that by using at least two first bus bars per segment of the first surface electrode, the necessary operating voltage of the arrangement can be reduced.Despite the lower operating voltage, an increase in performance is achieved. Due to safety considerations, the operating voltage of electrically controlled glazing in motor vehicles must be kept as low as possible, so reducing the operating voltage is a decisive advantage for applications in motor vehicles.

[0017] The functional element has a plurality of side edges, particularly preferably four side edges. However, the functional element can also comprise more than four side edges. At least two side edges of the functional element are essentially opposite one another in pairs. In an embodiment with four side edges, this results in two pairs of two opposite side edges each. The opposite side edges of a functional element can run parallel to one another or not parallel to one another. The side edges do not have to be straight, but often have a bend. The length of opposite side edges can differ from one another. For example, the functional element can have a trapezoidal outline.

[0018] The functional element has multiple side edges, for example, four side edges. The at least two first bus bars, which contact the same segment of the first surface electrode, are arranged on opposite side edges of the functional element. The first bus bars each run adjacent to the corresponding side edge assigned to them. This leads to a more uniform voltage distribution and thus a more homogeneous switching behavior of the functional element. If the functional element is a PDLC element, for example, this also offers advantages in terms of reduced residual opacity in the transparent switched state. Furthermore, the remaining residual opacity in the transparent state is more evenly distributed across the surface of the functional element.However, if, in an embodiment not according to the invention, only one first bus bar is used per segment, the residual opacity in the vicinity of this bus bar is lower than at the opposite end of this segment. By using two opposing first bus bars per segment of the first surface electrode, a more visually appealing appearance is also achieved. This advantage is not only associated with PDLC elements; a more appealing appearance can also be expected for other functional elements.

[0019] The length of the first bus bars is preferably between 80% and 100%, particularly preferably at least 95%, of the width of the segment contacted by these bus bars. The width of a segment of the first surface electrode is defined as the distance between two adjacent separating lines or, in the case of an edge-positioned segment, as the distance between the side edge and the nearest separating line. The separating lines and the first bus bars are preferably arranged at an angle of 70° to 110° to one another, particularly preferably at an angle of 90° ± 5° to one another. Because the first bus bars span 80% to 100% of the segment width, the length of the first bus bars within a segment is maximized. This is advantageous in order to achieve the greatest possible robustness of the first bus bars and good voltage distribution.

[0020] The segments of the first surface electrode are arranged substantially parallel to one another, wherein the segments extend continuously from one side edge of the functional element to an opposite side edge.

[0021] In a preferred embodiment, exactly two first bus bars are contacted on each segment of the first surface electrode, which are applied to the segment on opposite side edges of the functional element and extend between the dividing lines delimiting the segment, or between the side edge of the functional element and the dividing line. These two first bus bars per segment are each applied flatly to the first surface electrode of the respective segment and run adjacent to the nearest side edge of the functional element. The length of the bus bars is preferably at least 95% of the segment width. This embodiment of the invention is optimized with regard to a homogeneous circuit diagram of the functional element (bus bars on both sides) and with regard to the greatest possible length of the bus bars (only one bus bar per side).

[0022] The number of segments within the first surface electrode can vary depending on the application of the glazing and is usually between 2 and 20, preferably between 3 and 10.

[0023] In a first preferred embodiment, only one busbar is attached to the second surface electrode, via which the entire second surface electrode is electrically connected. This is advantageous, for example, if the functional element does not extend over the entire surface of the glazing and one edge of the functional element lies within the view-through area of ​​the glazing. A second busbar is omitted at this side edge for the sake of an attractive appearance.

[0024] In a second preferred embodiment, the functional element has at least one additional second busbar, thereby achieving a more homogeneous voltage distribution and a more uniform switching behavior. Preferably, the second busbars are arranged on opposite side edges of the functional element, each adjacent to these side edges, in order to achieve a homogeneous voltage distribution. Particularly preferably, the second surface electrode has exactly two opposing second busbars, whereby the length of the busbars along the side edge of the functional element can be maximized.

[0025] In both described embodiments, the length of the at least one second busbar is at least 70%, preferably at least 90%, of the length of the nearest side edge of the functional element, wherein the busbars are arranged adjacent to one of the side edges of the functional element. Preferably, the second busbars are arranged on the side edge(s) of the functional element at which no first busbars are located. Such an arrangement of the first and second busbars on different side edges of the functional element enables simple application of the busbars to the surface electrodes, which will be discussed in detail in the course of the method for producing the composite pane according to the invention.

[0026] The electrical connection of the bus bars to an external power source is achieved by suitable connecting cables, such as foil conductors. Suitable external control elements for controlling the individual segments are known to those skilled in the art.

[0027] The electrical control of the functional element is achieved, for example, using buttons, rotary controls, or sliders, which are integrated, for example, into the instrument panel of a vehicle. However, a control button, such as a capacitive button, can also be integrated into the composite pane. Alternatively, the functional element can also be controlled using contactless methods, such as by recognizing gestures, or based on the state of the pupil or eyelid, as determined by a camera and suitable evaluation electronics.

[0028] The dividing lines are incorporated into the surface electrodes in such a way that the segments of the first surface electrode are electrically insulated from one another. The individual segments are connected to the voltage source independently of one another, allowing them to be controlled separately. This allows different areas of the functional element to be switched independently. Particularly preferably, the dividing lines and the segments are arranged horizontally in the installed position. This allows the height of the non-transparent area of ​​the functional element to be controlled by the user. The term "horizontal" is to be interpreted broadly here and refers to a propagation direction that runs between the side edges of the laminated pane, for example, the side edges of a windshield or a roof pane.The dividing lines don't necessarily have to be straight, but can also be slightly curved, preferably adapted to any curvature of the nearest window edge, especially essentially parallel to the front roof edge of a windshield. Vertical insulation lines are also conceivable.

[0029] The dividing lines have a width of, for example, 5 µm to 500 µm, in particular 20 µm to 200 µm. The width of the segments, i.e., the spacing between adjacent dividing lines, can be selected by the person skilled in the art according to the requirements of the individual case.

[0030] The separation lines can be introduced by laser ablation, mechanical cutting, or etching during the manufacturing of the functional element. Already laminated multilayer films can also be subsequently segmented using laser ablation.

[0031] The bus bars are connected to the surface electrodes, for example, as strips of an electrically conductive material or electrically conductive prints. The bus bars are preferably designed as electrically conductive prints comprising silver.

[0032] The bus bars are each attached flatly to the first surface electrode and the second surface electrode. This is advantageous in terms of simple application of the bus bars. Furthermore, flat contacting is preferable to contacting across the surface cross-section in terms of its mechanical stability. The bus bars are preferably spaced from the nearest side edge of the functional element by a distance of 1 mm to 50 mm, particularly preferably 1 mm to 5 mm.

[0033] The side edges of the functional element, in the vicinity of which busbars are located on the functional element, are preferably arranged at a distance of 0 mm to 100 mm, preferably 1 mm to 50 mm, particularly preferably 1 mm to 20 mm, from the peripheral edge of the laminated pane. This advantageously increases the pane area equipped with the functional element. Furthermore, the busbars can be concealed in this way by the peripheral masking print in the edge area of ​​windshields and roof windows, which is common in the automotive sector. Side edges of a functional element where no busbars are located can, for example, also be located in the area of ​​the laminated pane that is visible after installation.

[0034] In an advantageous embodiment, the functional element is a PDLC functional element ( polymer dispersed liquid crystalThe active layer of a PDLC functional element contains liquid crystals embedded in a polymer matrix. If no voltage is applied to the surface electrodes, the liquid crystals are randomly aligned, which leads to strong scattering of the light passing through the active layer. If a voltage is applied to the surface electrodes, the liquid crystals align in a common direction, and the transmission of light through the active layer is increased. Such a functional element is known, for example, from DE 102008026339 A1.

[0035] In other possible embodiments, the active layer is an SPD, an electrochromic or an electroluminescent layer.

[0036] An SPD functional element ( suspended particle device) contains an active layer comprising suspended particles, wherein the absorption of light by the active layer can be changed by applying a voltage to the surface electrodes. The change in absorption is based on the alignment of the rod-like particles in the electric field when an electrical voltage is applied. SPD functional elements are known, for example, from EP 0876608 B1 and WO 2011033313 A1.

[0037] In an electrochromic functional element, the active layer of the functional element is an electrochemically active layer. The transmission of visible light depends on the degree of ion incorporation into the active layer, with the ions being provided, for example, by an ion storage layer between the active layer and a surface electrode. The transmission can be influenced by the voltage applied to the surface electrodes, which causes the ions to migrate. Suitable functional layers contain, for example, at least tungsten oxide or vanadium oxide. Electrochromic functional elements are known, for example, from WO 2012007334 A1, US 20120026573 A1, WO 2010147494 A1, and EP 1862849 A1.

[0038] In electroluminescent functional elements, the active layer contains electroluminescent materials, particularly organic electroluminescent materials, whose luminescence is stimulated by applying a voltage. Electroluminescent functional elements are known, for example, from US 2004227462 A1 and WO 2010112789 A2. The electroluminescent functional element can be used as a simple light source or as a display with which any desired image can be shown.

[0039] In a particularly preferred embodiment, the composite pane is a windshield of a motor vehicle. The windshield comprises an upper edge and a lower edge as well as two side edges running between the upper edge and the lower edge. The upper edge, the lower edge and the two side edges together form the circumferential edge of the composite pane. The upper edge refers to the edge which is intended to point upwards in the direction of the vehicle roof in the installed position. The upper edge is generally referred to as the roof edge or front roof edge. The lower edge refers to the edge which is intended to point downwards in the direction of the vehicle hood in the installed position. The lower edge is generally referred to as the engine edge. The side edges of the windshield are the pane edges which, when installed, are adjacent to the so-called A-pillars of the vehicle body.

[0040] Windshields have a central field of vision, the optical quality of which is subject to stringent requirements. This central field of vision must exhibit high light transmission (typically greater than 70%). This central field of vision is specifically the field of vision referred to by experts as field of vision B, field of vision B, or zone B. Field of vision B and its technical requirements are defined in Regulation No. 43 of the Economic Commission for Europe of the United Nations (UN / ECE) (ECE-R43, "Uniform Provisions Concerning the Approval of Safety Glazing Materials and Their Installation on Vehicles"). Field of vision B is defined in Annex 18.

[0041] In this windshield design, the functional element is a sun visor and is positioned above the central field of vision (field of vision B). This means that the functional element is located in the area between the central field of vision and the front roof edge of the windshield. The functional element does not have to cover the entire area, but is positioned entirely within this area and does not protrude into the central field of vision. In other words, the functional element is closer to the top edge of the windshield than the central field of vision. Thus, the transmission of the central field of vision is not impaired by the functional element, which is positioned in a similar position to a classic mechanical sun visor when folded down.

[0042] The interlayer in the central field of vision of the windshield is clear and transparent. This ensures that visibility through the central field of vision is not restricted, allowing the windshield to be used as a windshield. A transparent thermoplastic interlayer is defined as a layer with a light transmission in the visible spectral range of at least 70%, preferably at least 80%. The transparent interlayer is present at least in field of vision A, and preferably also in field of vision B, according to ECE-R43.

[0043] The windshield is preferably intended for a motor vehicle, particularly preferably for a passenger car.

[0044] The functional element as a sun visor has several slats, the dimensions and arrangement of which correspond to the segments of the first surface electrode and can be selectively switched. At least two dividing lines are incorporated in the first surface electrode, which run essentially parallel to the front roof edge and divide the surface electrode into at least three segments. The segments thus extend between the two side edges of the windshield. Each segment of the first surface electrode is contacted by two first bus bars, which are attached to the first surface electrode near the side edges. Accordingly, there is one bus bar per segment on each side edge of the windshield, each arranged adjacent to the nearest side edge of the windshield.The second surface electrode of the functional element is contacted via a second bus bar located adjacent to the front edge of the roof. The second bus bar runs essentially parallel to the front edge of the roof. The first bus bars located on the side edges and the second bus bar located on the roof edge are concealed in the edge area of ​​the pane by the opaque masking print commonly used on windshields. The windshield thus features an electrically switchable sun visor with consistent switching behavior, a low risk of failure, and an attractive appearance.

[0045] In one possible embodiment, a region of the thermoplastic intermediate layer, via which the functional element is connected to the outer pane or the inner pane, is tinted or colored. The transmission of this region in the visible spectral range is thus reduced compared to a non-tinted or tinted layer. The tinted / tinted region of the thermoplastic intermediate layer thus reduces the transmission of the windshield in the area of ​​the sun visor. In particular, the aesthetic impression of the functional element is improved because the tint results in a more neutral appearance that is more pleasant to the observer.

[0046] The tinted or colored area of ​​the thermoplastic intermediate layer preferably has a transmission in the visible spectral range of 10% to 50%, particularly preferably 20% to 40%. This achieves particularly good results in terms of glare protection and visual appearance.

[0047] A windshield with an electrically adjustable sun visor comprises at least one outer pane and one inner pane, which are connected to one another via an intermediate layer. The windshield is intended to separate the interior of a vehicle from the exterior environment in a window opening. For the purposes of the invention, the "inner pane" refers to the windshield pane facing the interior (vehicle interior). The "outer pane" refers to the pane facing the exterior environment. The first pane and the second pane of the composite pane according to the invention represent the inner pane and the outer pane of such a windshield.

[0048] In a further preferred embodiment of the composite pane according to the invention, it is used as a roof pane of a motor vehicle. The roof pane comprises a front roof edge adjacent to the vehicle's windshield, a rear roof edge facing the rear window, and two side edges running along the vehicle doors between the front and rear roof edges. The functional element is designed as a large-area shading element for the roof pane, with the functional element being arranged over an area of ​​at least 80% of the entire viewable area of ​​the roof pane, preferably at least 90%, for example 100%, of the entire viewable area.

[0049] The functional element as a roof shading device also has several slats, the dimensions and arrangement of which correspond to the segments of the first surface electrode and can be switched selectively. The segments of such a vehicle roof are selected to be significantly larger than those of sun visors. The functional element is arranged such that the side edges of the functional element run essentially parallel to the nearest edge (front roof edge, rear roof edge, side edges) of the composite pane. At least one dividing line is introduced into the first surface electrode, which runs essentially parallel to the front roof edge of the composite pane and divides the surface electrode into at least two segments. The functional element is preferably divided into 2 to 6, particularly preferably 3 to 4 slats, wherein the slats run essentially orthogonal to the direction of travel of the vehicle.The segments thus extend between the two side edges of the roof panel, and the dividing lines run from one side edge towards the other side edge. Each segment of the first surface electrode is contacted by two first bus bars, which are attached to the first surface electrode near the side edges. Accordingly, there is one bus bar per segment on each side edge of the roof panel. The second surface electrode of the functional element is contacted by two second bus bars, which are arranged adjacent to the front and rear roof edges. The second bus bars run essentially parallel to the nearest roof edge (front or rear roof edge). The first bus bars located on the side edges and the second bus bars arranged on the roof edges are concealed by the opaque masking print typically used in the edge region of the panel.The roof panel with switchable functional element also has a homogeneous switching behavior, a low risk of failure and an attractive appearance.

[0050] In a preferred embodiment of the roof pane, the region of the thermoplastic intermediate layer via which the functional element is connected to the outer pane or the inner pane is tinted or colored. The transmission of this region in the visible spectral range is thus reduced compared to a non-tinted or colored layer. The tinted / colored region of the thermoplastic intermediate layer thus reduces the transmission of the windshield in the area of ​​the sun visor. The tinted or colored region of the thermoplastic intermediate layer preferably has a transmission in the visible spectral range of 10% to 50%, particularly preferably of 20% to 40%. This achieves particularly good results in terms of glare protection and visual appearance.

[0051] The first pane and the second pane of the composite pane according to the invention represent the inner pane and the outer pane of the roof pane.

[0052] The first bus bars and the second bus bars comprise an electrically conductive structure, preferably containing silver, and have a thickness of 5 µm to 40 µm.

[0053] The bus bars are designed to be connected to an external voltage source so that an electrical potential difference exists between the first surface electrode and the second surface electrode.

[0054] The bus bars can be attached in particular by laying on, printing on, soldering or gluing.

[0055] In a preferred embodiment, the bus bars are formed as a printed and fired-in conductive structure. The printed bus bars contain at least one metal, preferably silver. The electrical conductivity is preferably achieved via metal particles contained in the bus bar, particularly preferably via silver particles. The metal particles can be located in an organic and / or inorganic matrix such as pastes or inks, preferably as a fired screen printing paste with glass frits. The layer thickness of the printed bus bars is preferably from 5 µm to 40 µm, particularly preferably from 8 µm to 20 µm, and most preferably from 10 µm to 15 µm. Printed bus bars with these thicknesses are technically simple to realize and have an advantageous current-carrying capacity.

[0056] Alternatively, the bus bars are formed as strips of electrically conductive foil. The current bus bars then contain, for example, at least aluminum, copper, tinned copper, gold, silver, zinc, tungsten and / or tin or alloys thereof. The strip preferably has a thickness of 10 µm to 500 µm, particularly preferably 30 µm to 300 µm. Bus bars made of electrically conductive foils with these thicknesses are technically simple to produce and have advantageous current-carrying capacity. The strip can be electrically conductively connected to the surface electrode, for example via a solder compound, an electrically conductive adhesive or an electrically conductive adhesive tape, or by direct application. To improve the conductive connection, a silver-containing paste, for example, can be arranged between the surface electrode and the bus bar.

[0057] The first surface electrode and the second surface electrode are each formed by an electrically conductive layer. These electrically conductive layers contain at least one metal, a metal alloy, or a transparent conductive oxide, preferably a transparent conductive oxide, and have a thickness of 10 nm to 2 µm. The surface electrodes are preferably transparent. Transparent here means permeable to electromagnetic radiation, preferably electromagnetic radiation with a wavelength of 300 nm to 1,300 nm, and in particular to visible light. Electrically conductive layers according to the invention are known, for example, from DE 20 2008 017 611 U1, EP 0 847 965 B1, or WO2012 / 052315 A1. They typically contain one or more, for example, two, three, or four electrically conductive, functional individual layers.The functional individual layers preferably contain at least one metal, for example silver, gold, copper, nickel and / or chromium, or a metal alloy. The functional individual layers particularly preferably contain at least 90 wt.% of the metal, in particular at least 99.9 wt.% of the metal. The functional individual layers can consist of the metal or the metal alloy. The functional individual layers particularly preferably contain silver or a silver-containing alloy. Such functional individual layers have particularly advantageous electrical conductivity with simultaneous high transmission in the visible spectral range. The thickness of a functional individual layer is preferably from 5 nm to 50 nm, particularly preferably from 8 nm to 25 nm. In this thickness range, advantageously high transmission in the visible spectral range and particularly advantageous electrical conductivity are achieved.

[0058] In principle, the surface electrodes can be formed by any electrically conductive layer that can be electrically contacted.

[0059] The functional element is preferably provided as a multilayer film with two outer carrier films. In such a multilayer film, the surface electrodes and the active layer are arranged between the two carrier films. By outer carrier film, we mean that the carrier films form the two surfaces of the multilayer film. The functional element can thus be provided as a laminated film that can be advantageously processed. The functional element is advantageously protected from damage, in particular corrosion, by the carrier films. The multilayer film contains, in the specified order, at least a first carrier film, a first surface electrode, an active layer, a second surface electrode, and a second carrier film.

[0060] The first carrier film and / or the second carrier film preferably contain at least one polymer that does not completely melt in the autoclave process, preferably polyethylene terephthalate (PET). The first and second carrier films particularly preferably consist of a PET film. This is particularly advantageous with regard to the stability of the multilayer film. However, the carrier films can also contain, for example, ethylene vinyl acetate (EVA) and / or polyvinyl butyral (PVB), polypropylene, polycarbonate, polymethyl methacrylate, polyacrylate, polyvinyl chloride, polyacetate resin, casting resins, acrylates, fluorinated ethylene propylene, polyvinyl fluoride and / or ethylene tetrafluoroethylene. The thickness of each carrier film is preferably from 0.1 mm to 1 mm, particularly preferably from 0.1 mm to 0.2 mm. The carrier films according to the invention are preferably transparent.The surface electrodes are preferably arranged on a surface of the carrier film, i.e., on exactly one of the two sides of the carrier film (i.e., on its front side or its back side). The carrier films are aligned in the layer stack of the multilayer film such that the surface electrodes are arranged adjacent to the active layer.

[0061] For the purposes of the invention, electrically controllable optical properties are understood to mean properties that are continuously controllable, but equally also those that can be switched between two or more discrete states.

[0062] In addition to the active layer and the surface electrodes, the functional element can of course have other known layers, for example barrier layers, blocking layers, anti-reflection layers, protective layers and / or smoothing layers.

[0063] Functional elements in the form of multilayer films are commercially available. The functional element to be integrated is typically cut from a multilayer film with larger dimensions in the desired shape and size. This can be done mechanically, for example, with a knife. In an advantageous embodiment, the cutting is done using a laser. It has been shown that the side edge is more stable in this case than with mechanical cutting. With mechanically cut side edges, there is a risk of the material shrinking, which is visually noticeable and adversely affects the aesthetics of the pane.

[0064] In an advantageous embodiment, the functional element has an edge seal. The edge seal covers the entire side edge of the functional element and, in particular, prevents the diffusion of chemical components of the thermoplastic intermediate layer, such as plasticizers, into the active layer. At least along the lower edge of the functional element, which is visible through windshields, and preferably along all side edges, the edge seal is formed by a transparent, colorless adhesive or a transparent, colorless adhesive tape. For example, acrylic- or silicone-based adhesive tapes can be used as edge seals. The transparent, colorless edge seal has the advantage that the edge of the functional element is not obtrusive when viewed through the windshield.Such edge sealing is preferably also used on non-visible side edges, for example on roof windows or on the edge areas of the windshield that are covered by masking print.

[0065] The functional element is integrated via an intermediate layer between the first pane and the second pane of the composite pane. The intermediate layer preferably comprises a first thermoplastic composite film that connects the functional element to the first pane, and a second thermoplastic composite film that connects the functional element to the second pane. Typically, the intermediate layer is formed by at least the first and second thermoplastic composite films, which are arranged flat on top of one another and laminated to one another, with the functional element being inserted between the two layers. The areas of the composite films that overlap with the functional element then form the areas that connect the functional element to the panes.In other areas of the pane, where the thermoplastic composite films are in direct contact with each other, they may fuse during lamination to such an extent that the two original layers may no longer be recognizable and a homogeneous intermediate layer is present instead.

[0066] A thermoplastic composite film can, for example, be formed from a single thermoplastic film. A thermoplastic composite film can also be formed from sections of different thermoplastic films whose side edges are joined together. In addition to a first thermoplastic composite film or a second thermoplastic composite film, further thermoplastic composite films can also be present. These can also be used, if necessary, to embed additional films comprising functional layers, for example, infrared-reflecting layers or acoustically dampening layers.

[0067] The thermoplastic composite films can, as already discussed using the example of windshields and roof windows, also contain tinted or colored areas. Such films are obtainable, for example, by coextrusion. Alternatively, an untinted film section and a tinted or colored film section can be combined to form a thermoplastic composite film. The tinted or colored area can be homogeneously colored or tinted, i.e., have a location-independent transmission. However, the tint or coloring can also be inhomogeneous; in particular, a transmission gradient can be realized. In one embodiment of a windshield, the transmittance in the tinted or colored area decreases, at least in sections, with increasing distance from the front roof edge of the windshield.This avoids sharp edges in the tinted or colored area, so that the transition from a sun visor to the transparent area of ​​the windshield is gradual, which is more aesthetically pleasing.

[0068] In an advantageous embodiment, the area of ​​the thermoplastic composite pane that is oriented toward a pane used as the outer pane of a vehicle—i.e., the area between the functional element and the outer pane—is tinted. This creates a particularly aesthetic impression of the vehicle when viewed from the outside. The area of ​​the other thermoplastic composite pane between the functional element and the inner pane can optionally be additionally colored or tinted.

[0069] In a preferred embodiment, the functional element, or more precisely the side edges of the functional element, is surrounded all around by a thermoplastic frame film. The frame film is frame-like with a recess into which the functional element is inserted. The thermoplastic frame film can be formed by a thermoplastic film into which the recess has been cut out. Alternatively, the thermoplastic frame film can also be composed of several film sections around the functional element. In a preferred embodiment, the intermediate layer is thus formed from a total of at least three thermoplastic composite films arranged flat on top of one another, with the frame film having a recess as the middle layer in which the functional element is arranged.During production, the thermoplastic frame film is positioned between the first and second thermoplastic composite films, with the side edges of all thermoplastic films preferably overlapping. The thermoplastic frame film preferably has approximately the same thickness as the functional element. This compensates for the local thickness difference of the windshield introduced by the locally limited functional element, thus preventing glass breakage during lamination.

[0070] The side edges of the functional element visible through the laminated glass are preferably arranged flush with the thermoplastic frame film, so that there is no gap between the side edge of the functional element and the associated side edge of the thermoplastic frame film. This applies in particular to the lower edge of a functional element such as a sun visor on a windshield, where this edge is typically visible. This makes the boundary between the thermoplastic frame film and the functional element visually less noticeable.

[0071] Automotive glazing, particularly windshields, rear windows, and roof windows, usually has a peripheral masking print made of opaque enamel, which serves in particular to protect the adhesive used to install the pane from UV radiation and to visually conceal it. This peripheral masking print is preferably used to also conceal the edges of the functional element located in the edge region of the glazing. The bus bars and the necessary electrical connections are also attached in the area of ​​the masking print. In this way, the functional element is advantageously integrated into the appearance of the composite pane. Preferably, at least the pane used as the outer pane has such a masking print; particularly preferably, both the first pane and the second pane (inner pane and outer pane) are printed, so that visibility from both sides is prevented.

[0072] The functional element may also have recesses or holes, for example, in the area of ​​so-called sensor windows or camera windows. These areas are intended for the installation of sensors or cameras whose functionality would be impaired by an adjustable functional element in the beam path, such as rain sensors.

[0073] The functional element is preferably arranged across the entire width of the composite pane, minus a border area on both sides with a width of, for example, 2 mm to 20 mm. The functional element is also preferably spaced from the upper edge by, for example, 2 mm to 20 mm. The functional element is thus encapsulated within the intermediate layer and protected from contact with the surrounding atmosphere and corrosion.

[0074] The first thermoplastic composite film and the second thermoplastic composite film and optionally also the thermoplastic frame film preferably contain at least polyvinyl butyral (PVB), ethylene vinyl acetate (EVA) and / or polyurethane (PU), particularly preferably PVB.

[0075] The thickness of each thermoplastic composite film and the frame film is preferably from 0.2 mm to 2 mm, particularly preferably from 0.3 mm to 1 mm, in particular from 0.3 mm to 0.5 mm, for example 0.38 mm.

[0076] The first pane and the second pane are preferably made of glass, particularly preferably soda-lime glass, as is common for window panes. However, the panes can also be made of other types of glass, such as quartz glass, borosilicate glass, or aluminosilicate glass, or of rigid, clear plastics, such as polycarbonate or polymethyl methacrylate. The panes can be clear, tinted, or colored. If the laminated pane is used as a windshield, it should have sufficient light transmission in the central viewing area, preferably at least 70% in the main viewing area A according to ECE-R43.

[0077] The outer pane, the inner pane and / or the intermediate layer may have further suitable coatings known per se, for example anti-reflective coatings, non-stick coatings, anti-scratch coatings, photocatalytic coatings or sun protection coatings or low-E coatings.

[0078] The thickness of the first and second panes can vary widely and thus be adapted to the requirements of the individual case. The first and second panes preferably have thicknesses of 0.5 mm to 5 mm, particularly preferably 1 mm to 3 mm.

[0079] The invention also comprises a method for producing a composite pane according to the invention, wherein at least a) a functional element is provided, b) at least one dividing line is introduced into the first surface electrode of the functional element, which divides the first surface electrode into at least two segments, c) at least two first bus bars per segment are attached to the first surface electrode, d) at least one second bus bar is attached to the second surface electrode, e) at least one first thermoplastic composite film is placed on a first disc, the functional element is placed on the first thermoplastic composite film, at least one second thermoplastic composite film and a second disc are arranged one above the other in this order on the functional element, f) the first disc and the second disc are joined by lamination, wherein an intermediate layer with an embedded functional element is formed from the first thermoplastic composite film and the second thermoplastic composite film.

[0080] The functional element is preferably provided in the form of a multilayer film comprising, in this order, a first carrier film, an active layer, and a second carrier film, wherein the surface electrodes are applied to the surfaces of the carrier films facing the active layer. The advantage of a multilayer film with electrically switchable optical properties lies in the simple production of the glazing. The actual functional element is advantageously protected from damage, in particular corrosion, by the carrier films and can also be provided in larger quantities before the glazing is manufactured, which can be desirable for economic and process-technical reasons. The multilayer film can simply be inserted into the composite during production of the composite pane, which is then laminated using conventional methods.

[0081] The introduction of the at least one separating line in step b) is preferably carried out using a laser process. The separating lines are preferably created by laser-induced degeneration within the surface electrodes. Such laser-induced degeneration is, for example, the ablation of the surface electrode or a chemical modification of the surface electrode. The laser-induced degeneration interrupts the electrical conductivity of the layer. A pulsed solid-state laser is preferably used as the laser.

[0082] The separation lines are preferably created through the carrier foil closest to the surface electrode to be processed. The laser is focused through this carrier foil onto the surface electrode.

[0083] The electrical contacting of the surface electrodes of the functional element is preferably carried out after the separation lines have been introduced, but can optionally also take place before.

[0084] The bus bars are preferably implemented in the form of a printed and fired conductive structure. The printed bus bars contain at least one metal, preferably silver. Suitable silver printing pastes are commercially available and known to those skilled in the art.

[0085] To specifically contact a surface electrode with a busbar, the electrode must first be exposed from the multilayer film. In a first step, a carrier film of the multilayer film, including the surface electrode located on the carrier film, is cut back. The thus exposed active layer is removed, for example, by mechanical abrasion using a solvent. After removing the active layer, the adjacent surface electrode is exposed and can be electrically contacted by printing the busbar onto it.

[0086] If multiple bus bars are arranged adjacent to one another, such as a group of first bus bars along an edge, the decoating of the area to be contacted is generally performed in a single step for all adjacent bus bars. To simplify the manufacturing process as much as possible, the area of ​​the multilayer film located between adjacent first bus bars is also decoated.

[0087] If the described contacting method is used, the first and second bus bars on the first and second surface electrodes are contacted starting from different surfaces of the multilayer film. To contact a first surface electrode on a first carrier film, the second carrier film is cut back, the active layer is removed, and the bus bars are applied from the side of the removed second carrier film. Analogously, to contact the second surface electrode on the second carrier film, the first carrier film is cut back. The first bus bars and the second bus bars are therefore not congruent when this method is used.

[0088] The bus bars are provided with connecting cables, for example in the form of flat conductors, in a manner known to those skilled in the art, which are led out of the disc assembly in order to be connected to an external power source.

[0089] Any existing prints, such as opaque cover prints and printed bus bars for electrical contact with the functional element, are preferably applied using the screen printing process.

[0090] To integrate the functional element into a composite pane, a layer stack of the individual components is first created. For this purpose, a first pane and a second pane are provided, which act as the inner pane and outer pane of the composite pane. These can be planar or curved, preferably congruently curved. At least one first thermoplastic composite film is placed on a first pane. The functional element is placed on the first thermoplastic composite film. Optionally, a thermoplastic frame film can be added, which surrounds the functional element like a passepartout. At least one second thermoplastic composite film and a second pane are arranged one above the other in this order on the functional element. Optionally, in addition to the thermoplastic composite films mentioned, further thermoplastic composite films and / or carrier films with functional layers can also be inserted into the composite.

[0091] The first pane and the second pane are bonded together by lamination to form a composite pane. Lamination is preferably carried out under the influence of heat, vacuum, and / or pressure. Known lamination methods can be used, for example, autoclave processes, vacuum bag processes, vacuum ring processes, calender processes, vacuum laminators, or combinations thereof.

[0092] The invention also encompasses the use of a composite pane according to the invention as building glazing or vehicle glazing, preferably as vehicle glazing, in particular as a windshield or roof window of a motor vehicle.

[0093] The invention is explained in more detail with reference to drawings and exemplary embodiments. The drawings are schematic representations and not to scale. The drawings do not limit the invention in any way. They show: Figure 1a shows a plan view of an embodiment of a windshield according to the invention, Figure 1b shows a cross section through the windshield according to the invention from Figure 1a along the section line CC', Figure 2a the functional element 5 of the windscreen from Figures 1a and 1b , Figure 2b cross section through the functional element 5 from Figure 2a along the section line AA', Figure 2c shows a cross section through the functional element 5 from Figure 2a along the section line BB', Figure 3 a plan view of an embodiment of a roof panel according to the invention, Figure 4 a the functional element 5 of the roof panel from Figure 3 , Figure 4b shows a cross section through the functional element 5 from Figure 3b along the section line EE', Figure 5 shows an embodiment of the method according to the invention using a flow chart.

[0094] Figure 1a shows a plan view of a composite pane according to the invention, which is designed as a windshield of a motor vehicle. Figure 1b shows a cross-sectional view of the windshield according to Figure 1a along the section line CC'. The windshield comprises a first pane 1, which serves as the outer pane, and a second pane 2 as the inner pane. The inner pane is the pane facing the vehicle interior, while the outer pane faces the vehicle's surroundings. The first pane 1 and the second pane 2 are connected to one another via an intermediate layer 3. The first pane 1 has a thickness of 2.1 mm and is made of a green-tinted soda-lime glass. The second pane 2 has a thickness of 1.6 mm and is made of a clear soda-lime glass. The composite pane as a windshield has a front roof edge D facing the roof in the installed position and an engine edge M facing the engine compartment in the installed position.

[0095] The windshield is equipped with a functional element 5 as an electrically adjustable sun visor, which is mounted in an area above the central viewing area B (as defined in ECE-R43). The sun visor is formed by a commercially available PDLC multilayer film as functional element 5, which is embedded in the intermediate layer 3. The height of the sun visor is, for example, 21 cm. The intermediate layer 3 comprises a total of three thermoplastic composite films 6, 7, 8, each formed by a thermoplastic film with a thickness of 0.38 mm made of PVB. The first thermoplastic composite film 6 is connected to the first pane 1, the second thermoplastic composite film 7 to the second pane 2. The intermediate thermoplastic frame film 8 has a cutout into which the cut PDLC multilayer film is inserted with a precise fit, i.e., flush on all sides.The third thermoplastic layer thus forms a kind of passe-partout for the functional element 5, which is thus completely encapsulated in thermoplastic material and thus protected. The first thermoplastic composite film 6 optionally has a tinted area 10 arranged between the functional element 5 and the first pane 1. The light transmission of the windshield is thereby further reduced in the area of ​​the sun visor and the milky appearance of the PDLC functional element 5 in the diffusive state is softened. The aesthetics of the windshield are thus made significantly more appealing. In the case shown, the lower edges of the tinted area 10 and the PDLC functional element 5 are arranged flush. However, this is not necessarily the case.

[0096] The composite pane according to the invention has, in its embodiment as a windscreen according to Figure 1aa circumferential cover print 9, which conceals both the bonding of the windshield to the vehicle body and the electrical contacting of the surface electrodes of the functional element 5. The circumferential peripheral cover print 9 is formed by an opaque enamel on the interior-side surfaces (facing the interior of the vehicle in the installed position) of the first pane 1 and the second pane 2. The distance of the functional element 5 to the front roof edge D and the side edges of the windshield is smaller than the width of the cover print 9, so that the side edges 4.1, 4.2, 4.4 of the functional element 5 - with the exception of the side edge 4.3 facing the central field of vision B - are concealed by the cover print 9. The electrical connections and bus bars are also expediently attached in the area of ​​the cover print 9 and are thus advantageously concealed.

[0097] In a particularly convenient embodiment, the functional element 5 is controlled by a capacitive button located in the area of ​​the sun visor, with the driver determining the degree of darkening by the location where they touch the window. Alternatively, the sun visor can also be controlled by contactless methods, for example, by recognizing gestures, or depending on the state of the pupil or eyelid, as determined by a camera and suitable evaluation electronics.

[0098] The side edges of the functional element 5 are provided with a peripheral edge seal (not shown), which is formed by a transparent acrylic adhesive tape. Diffusion into or out of the active layer 11 is thereby prevented. Since the edge seal is transparent, the lower side edge, which is not covered by the cover print 9, is not noticeable. The edge seal runs circumferentially around the side edges of the multilayer film and, starting from the side edges, extends a few millimeters over the surfaces of the carrier films 14, 15 facing away from the active layer 11. The edge seal 10 particularly prevents the diffusion of plasticizers and other adhesive components of the thermoplastic frame film 8 into the active layer 11, thereby reducing the aging of the functional element 5.

[0099] For the thermoplastic composite films 6, 7 and the thermoplastic frame film 8, a so-called "high-flow PVB" is preferably used, which exhibits greater flow properties compared to standard PVB films. This allows the layers to flow more smoothly around the functional element 5, creating a more homogeneous visual impression and making the transition from the functional element 5 to the frame film 8 less noticeable. The "high-flow PVB" can be used for all or just one or more of the thermoplastic films 6, 7, 8 in direct contact with the functional element 5.

[0100] Figure 2a shows a top view of the functional element 5 of the windshield according to Figure 1a before integration of the functional element 5 into the windshield, whereby the electrical contacting of the functional element 5 is also visible. Figure 2b and 2c show cross sections through the functional element according to Figure 2aalong the section line AA' or BB'. The controllable functional element 5 is a multilayer film consisting of an active layer 11 between two surface electrodes 12, 13 and two carrier films 14, 15. The active layer 11 contains a polymer matrix with liquid crystals dispersed therein, which align themselves depending on the electrical voltage applied to the surface electrodes, whereby the optical properties can be controlled. The carrier films 14, 15 are made of PET and have a thickness of, for example, 0.125 mm. The carrier films 14, 15 are provided with an ITO coating facing the active layer 11 with a thickness of approximately 100 nm, which forms the first surface electrode 12 and the second surface electrode 13. The surface electrodes 12, 13 can be connected to the on-board electrical system via bus bars 18, 19 and connecting cables (not shown). The bus bars 18, 19 are formed by a silver-containing screen printing.The first surface electrode 12 has three separating lines 16, each 200 µm wide, which are introduced using a laser process and divide the first surface electrode 12 into four segments 17. The separating lines are spaced approximately 5 cm apart, or in the case of the peripheral segments, from the nearest side edge 4.1, 4.3. The separating lines 16 electrically insulate the segments 17 from one another. The number of segments 17 can be freely selected depending on the application or customer requirements. The first surface electrode 12 has two first bus bars 18 per segment 17, thus a total of 8 first bus bars 18. The two first bus bars 18 assigned to a segment 17 are located on opposite side edges 4.2, 4.4 of the functional element 5. The side edges 4.2, 4.4 of the functional element 5, which accommodate the first bus bars 18, are arranged on the side edges of the windshield (adjacent to the A-pillars of the vehicle body) in the installed position of the functional element 5. Figure 2cshows a cross-section along the section line BB', which shows the contacting of the first bus bars 18 on the first surface electrode 12. The second carrier film 15, the second surface electrode 13, and the active layer 11 have been removed in the area of ​​the functional element 5 provided for the first bus bars 18. The first bus bars 18 are screen-printed onto the thus exposed first surface electrode 12. The first bus bars 18 assume a maximum possible width corresponding to the distance between adjacent dividing lines 16 or between dividing line 16 and side edge 4.1 or 4.3. Care must be taken to ensure that the bus bar is printed exclusively within the assigned segment 17 in order to prevent a short circuit between adjacent segments 17. The second bus bar 19 ensures the electrical contacting of the second surface electrode 13. This is located on the side edge 4.1, which, in the installed position of the functional element 5, points towards the front edge of the roof. In this case, a single second busbar 19 is sufficient for electrically contacting the functional element 5. The side edge 4.3 opposite the second busbar 19 remains free, thereby ensuring a visually appealing transition to the remaining glazing surface. In the area of ​​the second busbar 19, according to . Figure 2b The first carrier foil 14, together with the first surface electrode 12, is removed by cutting back the foil. The active layer 11 is also removed in this area. The second busbar 19 is printed onto the exposed second surface electrode 13 and thereby electrically contacts the second surface electrode 13 in this area.

[0101] Figure 3shows a plan view of an embodiment of a composite pane according to the invention as a roof pane. The roof pane comprises a first pane 1, which serves as the outer pane, and a second pane 2 as the inner pane. The inner pane is the pane facing the vehicle interior, while the outer pane faces the vehicle's surroundings. The first pane 1 and the second pane 2 are connected to one another via an intermediate layer 3. The first pane 1 is made of clear soda-lime glass with a thickness of 2.1 mm. The second pane 2 is made of soda-lime glass with a thickness of 1.6 mm and is tinted gray. The tinted inner glass contributes to the attractive appearance of the pane, also for the vehicle occupants when looking through the roof pane. The composite pane as a roof pane has a front roof edge D facing the windshield in the installed position and a rear roof pane D' facing the rear window in the installed position.

[0102] The roof panel is equipped with a functional element 5 as a large-area shading system, wherein the functional element is formed by a commercially available PDLC multilayer film that is embedded in the intermediate layer 3. The structure of the intermediate layer 3 essentially corresponds to that in Figure 1a and 1b described, whereby, in contrast, the functional element extends over the entire viewing area of ​​the glazing. Also in the embodiment as a roof pane, the intermediate layer 3 is formed by the three thermoplastic composite films 6, 7, 8, as in Figures 1a and 1bdescribed. These are each formed from a thermoplastic film made of PVB with a thickness of 0.38 mm. The first thermoplastic composite film 6 is connected to the first pane 1, the second thermoplastic composite film 7 to the second pane 2. The intermediate thermoplastic frame film 8 has a cutout into which the cut PDLC multilayer film is inserted with a precise fit, i.e. flush on all sides. Depending on the thickness of the multilayer film and the resulting difference in thickness to the area without the functional element 5, the frame film 8 can be dispensed with. This also depends on the complexity of the pane bending of the composite pane. In general, it can be stated that a frame film can be dispensed with if the differences in thickness between areas with a functional element and areas without a functional element are small, and if the bending is not very complex.

[0103] The first thermoplastic composite film 6 and the second thermoplastic composite film 7 are tinted grey to make the appearance of the roof panel attractive.

[0104] Optionally, an additional thermoplastic composite film (not shown) can be applied adjacent to the outer pane (first pane 1). Carrier films with functional layers, such as a carrier film with an infrared-reflecting coating, can be integrated over the additional thermoplastic composite film. The infrared-reflecting coating is oriented toward the first pane 1 (outer pane) and serves to reduce heating of the passenger compartment due to solar radiation.

[0105] The roof panel according to the invention also has the circumferential cover print 9 already described for a windshield according to the invention, which conceals both the bonding of the windshield to the vehicle body and the electrical contacting of the surface electrodes of the functional element 5. The distance of the functional element 5 to the front roof edge D, the rear roof edge D', and the side edges of the roof panel is smaller than the width of the cover print 9, so that the side edges 4.1, 4.2, 4.3, 4.4 of the functional element 5 are concealed by the cover print 9. The electrical connections are also expediently arranged in the area of ​​the cover print 9 and thus advantageously concealed.

[0106] Figure 4a shows a top view of the functional element 5 of the roof panel according to Figure 3before integration of the functional element 5 into the composite pane, whereby the electrical contacting of the functional element 5 is also visible. Figure 4b shows a cross section through the functional element according to Figure 4a along the section line EE'. The adjustable functional element 5 is a multilayer film, which in its composition corresponds to the Figure 2aThe first surface electrode 12 has two separating lines 16, each 200 µm wide, which are introduced by laser technology and divide the first surface electrode 12 into three segments 17. The distance between the separating lines depends on the size of the roof pane, with the transparent area of ​​the pane being divided by the separating lines into three sub-areas of approximately equal area. The separating lines 16 electrically insulate the segments 17 from one another. The number of segments 17 can be freely selected depending on the application or customer requirements. The contacting of the segments 17 essentially corresponds to that in Figure 2a, 2b and 2cdescribed. The first surface electrode 12 has two first bus bars 18 per segment 17, thus a total of 6 first bus bars 18. The two first bus bars 18 assigned to a segment 17 are located on opposite side edges 4.2, 4.4 of the functional element 5. The side edges 4.2, 4.4 of the functional element 5, which accommodate the first bus bars 18, are arranged on the side edges of the roof window (above the side doors of the vehicle) in the installed position of the functional element 5. A cross section through the functional element according to Figure 4a along the section line BB' corresponds in its schematic structure to that already shown in Figure 2c shown. At this point, the contacting of the first busbar 18 on the first surface electrode 12 is described in detail. In contrast to the Figure 2adescribed functional element 5 as a sun visor, the functional element 5 intended as full-surface shading of a roof panel has Figure 4a via an additional second bus bar 19. Since all side edges 4.1, 4.2, 4.3, 4.4 of the functional element 5 lie outside the viewing area of ​​the pane and are concealed by the peripheral cover print 9, all side edges are available for contacting the surface electrodes. A second bus bar 19 is analogous to the one shown in Figure 2a described functional element 5 is arranged on the front roof edge D of the roof panel. On the opposite side edge 4.3 of the functional element 5, a further second busbar 19 is arranged along the rear roof edge D'. A cross section along the section line EE' of the functional element from Figure 4a is in Figure 4b The structure is analogous to that shown in Figure 2bdescribed, wherein, in contrast, along two opposite side edges 4.1, 4.3 of the functional element 5, the first carrier film 14, the first surface electrode 12 and the active layer 11 are removed in one area each and a second busbar 19 is printed on each.

[0107] The use of two second bus bars 19 is particularly advantageous in order to achieve a uniform voltage distribution even with large dimensions of the functional element 5.

[0108] Figure 5 shows an embodiment of the manufacturing method according to the invention using a flow chart comprising the steps: I Providing a functional element 5, II Introducing at least one dividing line 16 by means of a laser into the first surface electrode 12 of the functional element 5, wherein the at least one dividing line 16 divides the first surface electrode 12 into at least two segments 17, III Electrical contacting of the first surface electrode 12 with at least two first bus bars 18 per segment 17 and electrical contacting of the second surface electrode 13 with at least one second bus bar 19, IV Creating a layer stack comprising in this order at least: a first pane 1, a first thermoplastic composite film 6, the functional element 5, a second thermoplastic composite film 7 and a second pane 2, V Autoclaving the arrangement to produce a composite pane List of reference symbols:

[0109] 1First pane 2Second pane 3Intermediate layer 4.1, 4.2, 4.3, 4.4Side edges 5Functional element with electrically adjustable optical properties 6First thermoplastic composite film 7Second thermoplastic composite film 8Thermoplastic frame film 9Cover print 10Tinted area of ​​the first thermoplastic composite film 11Active layer of functional element 5 12First surface electrode of functional element 5 13Second surface electrode of functional element 5 14First carrier film 15Second carrier film 16Separation lines 17Segments 18First bus bars 19Second bus bars Dfront roof edge Drear roof edge Mengine edge Sside edges A-A', B-B', C-C', E-E'section line

Claims

1. Laminated pane having an electrically controllable functional element which can be switched in segments, at least comprising a first pane (1), a second pane (2), which are connected to one another via an intermediate layer (3), and a functional element (5) which is embedded in the intermediate layer (3), wherein - the functional element (5) comprises a first planar electrode (12) and a second planar electrode (13) which are arranged one above the other in a planar manner and between which an active layer (11) is arranged in a planar manner, - the functional element (5) has a plurality of side edges (4.1, 4.2, 4.3, 4.4), - the first planar electrode (12) is divided into a plurality of segments (17) by means of at least one separating line (16), - a group of first bus bars (18) electrically conductively contacts the first planar electrode (12), - at least one second bus bar (19) electrically conductively contacts the second planar electrode (13), and wherein each segment (17) of the first planar electrode (12) is electrically conductively contacted by two bus bars from the group of first bus bars (18), the two first bus bars (18) which contact the same segment (17) of the first planar electrode (12) are each arranged adjacent to opposite side edges (4.2, 4.4) of the functional element (5) and the at least one second bus bar (19) is attached adjacent to one of the side edges (4.1, 4.3) of the functional element (5) on which no bus bar of the group of first bus bars (18) is located.

2. Laminated pane according to claim 1, wherein the length of the first bus bars (18) is between 80% and 100% of the width of the contacted segment (17), wherein the width of the contacted segment (17) corresponds to the shortest distance between the separating lines (16) delimiting the segment (17) or, in the case of a marginal segment (17), to the distance between the side edge (4.1, 4.3) of the functional element (5) and the closest separating line (16).

3. Laminated pane according to either claim 1 or claim 2, wherein the length of the at least one second bus bar (19) corresponds to at least 70%, preferably at least 90%, of the length of the closest side edge (4.1, 4.3) of the functional element (5).

4. Laminated pane according to any of claims 1 to 3, wherein the functional element (5) is a PDLC functional element.

5. Laminated pane according to any of claims 1 to 4, wherein the functional element (5) has at least two second bus bars (19), and the at least two second bus bars (19) are arranged adjacent to opposite side edges (4.1, 4.3) of the functional element (5).

6. Laminated pane according to any of claims 1 to 4, wherein the laminated pane is a windscreen of a motor vehicle, comprising a motor edge (M), a front roof edge (D) and two side edges (S), the functional element (5) is designed as a sunshade in the vicinity of the front roof edge (D), and wherein - at least two separating lines (16) within the first planar electrode (12) extend substantially parallel to the front roof edge (D) and divide the first planar electrode (12) into at least three segments (17), - a second bus bar (19) extends adjacent to the side edge of the functional element (5) that is closest to the roof edge (D), and electrically conductively contacts the second planar electrode (13), - each segment (17) of the first planar electrode (12) is contacted by two first bus bars (18) in each case, and - within each segment (17) a first bus bar (18) is contacted adjacent to each of the two side edges (S) of the windscreen on the first planar electrode (12).

7. Laminated pane according to any of claims 1 to 5, wherein the laminated pane is a roof panel of a motor vehicle, comprising a front roof edge (D), a rear roof edge (D') and two side edges (S), the functional element (5) is designed as a large-area shade of the roof panel, and wherein - at least one separating line (16) within the first planar electrode (12) extends substantially parallel to the front roof edge (D) and / or rear roof edge (D') and divides the first planar electrode (12) into at least two segments (17), - a second bus bar (19) extends substantially parallel to the front roof edge (D) adjacent to the side edge of the functional element (5) that is closest to the front roof edge (D), and electrically conductively contacts the second planar electrode (13), - a further second bus bar (19) extends substantially parallel to the rear roof edge (D') adjacent to the side edge of the functional element (5) that is closest to the rear roof edge (D'), and electrically conductively contacts the second planar electrode (13), - each segment (17) of the first planar electrode (12) is contacted by two first bus bars (18) in each case, and - within each segment (17) a first bus bar (18) is contacted adjacent to each of the two side edges (S) of the roof panel on the first planar electrode (12).

8. Laminated pane according to any of claims 1 to 7, wherein the first bus bars (18) and the second bus bars (19) have an electrically conductive structure, preferably containing silver, and have a thickness of 5 µm to 40 µm.

9. Laminated pane according to any of claims 1 to 8, wherein the first planar electrode (12) and the second planar electrode (13) contain at least one metal, a metal alloy, or a transparent conductive oxide, preferably a transparent conductive oxide, and have a thickness of 10 nm to 2 µm.

10. Laminated pane according to any of claims 1 to 9, wherein the intermediate layer (3) has a first thermoplastic laminated film (6) which is arranged between the functional element (5) and the first pane (1), and a second thermoplastic laminated film (7) which is arranged between the functional element (5) and the second pane (2).

11. Laminated pane according to claim 10, wherein the functional element (5) is peripherally surrounded by a thermoplastic frame film (8) which is arranged between the first thermoplastic laminated film (6) and the second thermoplastic laminated film (7).

12. Method for producing a laminated pane according to any of claims 1 to 11, wherein at least a) a functional element (5) is provided, b) at least one separating line (16) is introduced into the first planar electrode (12) of the functional element (5), which separating line divides the first planar electrode (12) into at least two segments (17), c) at least two first bus bars (18) per segment (17) are attached to the first planar electrode (12), d) at least one second bus bar (19) is attached to the second planar electrode (13), e) at least one first thermoplastic laminated film (6) is placed onto a first pane (1), the functional element (5) is placed onto the first thermoplastic laminated film (6), and at least one second thermoplastic laminated film (7) and a second pane (2), in this order, are arranged one above the other on the functional element (5), f) the first pane (1) and the second pane (2) are connected by lamination, wherein an intermediate layer (3) having an embedded functional element (5) is formed from the first thermoplastic laminated film (6) and the second thermoplastic laminated film (7).

13. Use of a laminated pane according to any of claims 1 to 11 as building glazing or vehicle glazing, preferably as vehicle glazing, in particular as a windscreen or roof panel of a motor vehicle.