Composite pane having electrically controllable optical properties

Abstract

The present invention relates to a composite pane (100) having electrically controllable optical properties, comprising: an outer pane (1), a thermoplastic intermediate layer (3), an inner pane (2) and a function element (4) which is arranged between the outer pane (1) and the inner pane (2) and has electrically controllable optical properties, wherein the function element (4) comprises: - an active layer (5) having a first surface (A), a second surface (B) and a circumferential side face (S), - a first planar electrode (6.1) which extends over the first surface (A) in a first region (5.1) of the active layer (5), - a second planar electrode (6.2) which extends over the first surface (A) in a second region (5.2) of the active layer (5), - a third planar electrode (6.3) which extends over the second surface (B) at least in the first and in the second region (5.1, 5.2) of the active layer (5) and - an electric bridge (7) which connects the first planar electrode (6.1) to the third planar electrode (6.3) in an electrically conductive manner, wherein the first planar electrode (6.1) has a first projection region (U') with respect to the active layer and the second planar electrode (6.2) has a second projecting region (U'') with respect to the active layer (5) and at least on the first projecting region (U') a first bus line (8.1) is arranged and at least on the second projecting region (U'') a second bus line (8.2) is arranged, and wherein the first planar electrode (6.1) and the second planar electrode (6.2) are electrically insulated from one another.

Description

[0001] Composite pane with electrically controllable optical properties

[0002] The invention relates to a composite pane with a functional element, a method for its production, the use of such a composite pane and a glazing unit with the composite pane.

[0003] In the automotive and construction sectors, laminated glass panes with electrically controllable functional elements are often used for sun protection or privacy screening. For example, windshields are known in which a sun visor is integrated in the form of a functional element with electrically controllable optical properties. In particular, the transmission or scattering behavior of electromagnetic radiation in the visible range can be electrically controlled. The functional elements are usually film-like and are laminated into a laminated glass pane or glued to it. In windshields, for example, the driver can control the transmission behavior of the pane with regard to solar radiation. This eliminates the need for a conventional mechanical sun visor. This reduces the weight of the vehicle and frees up space in the roof area.In addition, electrically controlling the sun visor is more convenient for the driver than manually folding down the mechanical sun visor.

[0004] Windscreens with such electrically controllable sun visors are known, for example, from DE102013001334A1, DE102005049081 B3,

[0005] DE102005007427A1 and DE102007027296A1.

[0006] Typical electrically controllable functional elements contain electrochromic layer structures or single particle device (SPD) films. Other possible functional elements for implementing electrically controllable sun protection are so-called PDLC functional elements (polymer dispersed liquid crystal). Their 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 transmittance, but rather by increasing scattering to ensure glare protection. PDLC functional elements are known, for example, from US20150301367A1.One problem with laminated functional elements is the penetration of gas and the diffusion of plasticizers or other harmful compounds into the functional element. These substances often penetrate through the poorly protected side surfaces of the functional element, often leading to undesirable aging phenomena such as lightening and changes in shading. These problems occur particularly with PDLC functional elements.

[0007] JP 2008225399 discloses a liquid crystal display element on a flexible substrate, such as a plastic film, wherein the side surfaces have a gas barrier layer that prevents the penetration of gas via a side surface of the substrate. WO2019077014A1 and WO2018188844A1 disclose composite panes with a functional element, wherein the functional element is protected from the penetration of plasticizer from the thermoplastic intermediate layer by means of several barrier layers on the side surface.

[0008] The present invention is therefore based on the object of providing an improved functional element with electrically controllable optical properties, which has good aging resistance and can be produced cost-effectively.

[0009] The object of the present invention is achieved by a composite pane according to independent claim 1. Preferred embodiments are evident from the subclaims.

[0010] The composite pane according to the invention comprises an outer pane, a thermoplastic intermediate layer, an inner pane, and a functional element with electrically controllable optical properties arranged between the outer pane and the inner pane. The functional element comprises an active layer having a first surface, a second surface, and a circumferential side surface, a first surface electrode, a second surface electrode, a third surface electrode, and an electrical bridge that electrically connects the first surface electrode to the third surface electrode. The thermoplastic intermediate layer is arranged between the outer pane and the inner pane.

[0011] The active layer and the surface electrodes are foil-like and form a stacking sequence. Foils typically have a large surface area but only a small overall thickness. In the following, the large surfaces of the stacking sequence that delimit the stacking sequence are referred to as the upper surface and lower surface, and the orthogonal surfaces to them, which have only a small width (corresponding to the direction of the small overall thickness), are referred to as side surfaces. The first surface and the second surface of the active layer are arranged parallel to the lower and upper surfaces of the stacking sequence. The side surface of the active layer refers only to the side surface of the active layer, whereas when we talk about the side surface of the functional element, we mean the side surface of the entire stacking sequence. When we talk about “the side surface,” we mean the side surface of the active layer.

[0012] The first surface electrode extends in a first region of the active layer over the first surface of the active layer. The second surface electrode extends in a second region of the active layer over the first surface of the active layer. The third surface electrode extends at least in the first region of the active layer and in the second region of the active layer over the second surface of the active layer. Preferably, the third surface electrode extends over the entire second surface of the active layer. The electrical bridge electrically connects the first surface electrode to the third surface electrode.Preferably, the area of ​​the first region and the area of ​​the second region of the active layer result in the total area of ​​the active layer, so that the first surface electrode and the second surface electrode extend over the entire first surface of the active layer, less an insulation area, for example an insulation line, which is arranged between the first and the second surface electrode.

[0013] The active layer preferably has a first segment at least in the first region and a second segment at least in the second region. In other words: the active layer is preferably divided into a first segment at least in the first region and into a second segment at least in the second region. The first segment of the active layer is thus arranged substantially congruent with the first surface electrode and the second segment of the active layer is arranged substantially congruent with the second surface electrode. By dividing the active layer into segments, the appearance of the functional element is improved. If the active layer is not divided into individual segments, unsightly optical abnormalities can occur between the regions, for example a gradual optical change in the first region of the active layer when the optical properties of the second region change.The division of the active layer into at least a first segment and a second segment is preferably produced by segmentation using laser radiation. The first surface electrode has a first projecting region relative to the active layer, and the second surface electrode has a second projecting region relative to the active layer. A first bus bar is arranged at least on the first projecting region, and a second bus bar is arranged at least on the second projecting region. The first surface electrode and the second surface electrode are electrically insulated from one another. In other words, the first surface electrode projects beyond the active layer in a first section of the circumferential side surface, and the second surface electrode projects beyond the active layer in a second section of the circumferential side surface.A first bus bar is arranged at least on the projecting region of the first surface electrode, and a second bus bar is arranged at least on the projecting region of the second surface electrode. The first surface electrode and the second surface electrode are arranged so as to be electrically insulated from one another. Preferably, the first surface electrode is separated from the second surface electrode by an insulation line, which was introduced, for example, by laser ablation.

[0014] For the purposes of the invention, the "circumferential side surface of the active layer" refers to the outer circumferential surface that extends perpendicular to the first surface and the second surface of the active layer. The first and second surfaces of the active layer are the main surfaces of the active layer, which are arranged substantially parallel to the main surfaces of the outer pane and the inner pane of the composite pane. The circumferential side surface of the active layer thus comprises the circumferential side surfaces of any individual segments of the active layer that may be present, less those sections of the circumferential side surface of the segments that do not run along the edge of the functional element.In the context of the invention, this means that all sections of the circumferential side surface of the first segment that face the circumferential side surface of the second segment (or any additional segment of the active layer that may be present) are not part of the circumferential side surface of the active layer. This applies vice versa for all sections of the circumferential side surface of the second segment that face the circumferential side surface of the first segment (or any additional segment of the active layer that may be present).

[0015] If the active layer is divided into segments, “the first surface of the active layer” means the first surface of the first segment and the first surface of the second segment, as well as the first surface of any additional segments of the active layer that may be present. It is understood that “the second surface of the active layer” within the meaning of the invention means the second surface of the first segment and the second surface of the second segment, as well as the second surface of any additional segments of the active layer that may be present. The first surfaces of the individual segments are arranged next to one another, so that in a plan view of the composite pane, the first surfaces of the individual segments are offset vertically from one another, but not horizontally. This means: if the first surface of the first segment faces the outer pane, the first surface of the second segment necessarily also faces the outer pane.This also applies vice versa to the second surface of the first segment and the second surface of the first segment. In this case, the first surface of the active layer results from the first surface of the first segment and the first surface of the second segment, as well as the first surface of any additional segments that may be present. The second surface of the active layer results from the second surface of the first segment and the second surface of the second segment, as well as the second surface of any additional segments that may be present.

[0016] The bus bars are connected to the surface electrodes in such a way that when the first bus bar and the second bus bar are electrically contacted with a voltage source, different optical states of the functional element can be controlled. If an electrical potential is applied to the first surface electrode, the electrical potential is also applied to the third surface electrode via the electrical bridge. A counter potential is applied to the second surface electrode via the second bus bar, so that the second region of the active layer, which is arranged between the second surface electrode and the third surface electrode, can change its optical state according to the applied voltage difference between the surface electrodes. Since the second surface electrode and the first surface electrode are arranged electrically insulated from one another, no short circuit occurs.

[0017] A major advantage of the invention is that, using the inventive solution, the surface electrodes with bus bars can be arranged on only one surface of the active layer, thus providing design freedom during the production of the composite pane. Typically, a first bus bar must be connected to a surface electrode on the first surface of the active layer, and a second bus bar must be connected to a surface electrode on the second surface of the active layer. This requires more space, which can compromise the desired properties of the composite pane. Furthermore, production is significantly more complex, as the functional element must be contacted with bus bars from two sides.In the solution according to the invention, the first surface electrode extends over the first surface in the first region of the active layer and the second surface electrode extends over the first surface in the second region of the active layer. The first surface electrode is connected to the first busbar in a region of the first surface electrode protruding from the active layer and the second surface electrode is connected to the second busbar in a region of the second surface electrode protruding from the active layer. The first surface electrode and the second surface electrode largely prevent the diffusion of pollutants, for example plasticizers from the thermoplastic intermediate layer, via the first surface of the active layer into the active layer. This arrangement makes it possible to reduce the number of barrier layers for preventing pollutant diffusion into the active layer.This can slow down the aging of the functional element, which essentially occurs when harmful substances penetrate the interior of the functional element via the unprotected surfaces of the active layer and undesirably alter the optical properties of the functional element. Aging leads, for example, to a brightening or a change in the transmission of the functional element, starting at its side edges.

[0018] In a preferred embodiment of the invention, the first surface electrode, the second surface electrode, and any additional surface electrodes applied to the first surface of the active layer, together project along the entire circumferential side surface of the active layer. This means that the surface electrodes, minus one or more insulation regions arranged between the surface electrodes, project along the entire circumferential side surface of the active layer. The at least one insulation region between the first surface electrode and the second surface electrode serves to electrically insulate the surface electrodes from one another. The insulation region is preferably linear (insulation lines).Due to the largely uninterrupted projection of the surface electrodes along the circumferential side surface of the active layer, the active layer is very effectively protected against contaminant diffusion. This reduces the need for barrier layers, which saves material costs and minimizes processing effort. Preferably, the first projecting area and the second projecting area together project beyond the active layer along the entire circumferential side surface.

[0019] The first surface electrode and / or the second surface electrode preferably protrude at least 1 mm, preferably at least 5 mm, from the active layer. In other words, the first surface electrode and / or the second surface electrode and any further surface electrodes present have a projection u of at least 1 mm, particularly preferably of at least 5 mm, from the active layer. The projection is determined within the meaning of the invention by the distance from the outer edge of the surface electrode to the outer edge of the active layer in the projecting region. This means the distance orthogonal to the side surface of the active layer. If the projection is to be variable over the entire functional element, the projection u is preferably at least 1 mm on average, particularly preferably at least 5 mm. From a projection with the dimensions mentioned, bus bars can be connected to the surface electrode in a simplified process.

[0020] In a particularly preferred embodiment of the functional element, the active layer comprises further regions, preferably at least one further region, particularly preferably at least 3 further regions, very particularly preferably at least 5 further regions, in particular at least 8 further regions. Exactly one further surface electrode is applied to the first surface of each further region. Each region is electrically connected to exactly one surface electrode on the first surface and each further surface electrode is electrically connected to exactly one region of the active layer. The third surface electrode extends over the second surface of all further regions. The further surface electrodes each protrude beyond the active layer in a further section of the circumferential side surface of the active layer.Each additional surface electrode is preferably electrically connected to exactly one additional busbar, with the additional surface electrodes preferably being electrically connected to another busbar on their region projecting from the active layer. The additional surface electrodes, the first surface electrode, and the second surface electrode, are arranged so as to be electrically insulated from one another; for example, they are separated from one another by one or more linear insulation regions (insulation lines). By contacting the second region and the additional regions of the active layer with different surface electrodes, the regions of the active layer can be controlled and switched independently of one another.In this configuration, the first surface electrode, the electrical bridge, and the third surface electrode preferably serve as the anode, while the second surface electrode and the further surface electrode serve as the cathode and can have different (cathodical) electrical potentials. The voltage difference between the anode on one side and the cathodes on the other side can convert the individual regions of the active layer into different desired optical states. Particularly preferably, each region of the active layer is also an individual segment of the active layer, so that the first region is a first segment, the second region is a second segment, and each further region is a further segment.

[0021] In a preferred embodiment of the invention, the first surface electrode, the second surface electrode, and any additional surface electrodes are formed using laser radiation (laser ablation). In other words, an initially unsegmented, continuous surface electrode is divided into several surface electrodes (at least the first surface electrode and the second surface electrode) using laser radiation. The third surface electrode is preferably not segmented by laser radiation. Any segments of the active layer that may be present, i.e., at least the first segment and the second segment, are preferably also produced using laser radiation.In other words, an initially unsegmented active layer with a continuous surface electrode arranged on the first surface of the active layer was divided by laser radiation into several segments (at least the first and second segments) and several surface electrodes (at least the first surface electrode and the second surface electrode). The third surface electrode is not segmented by laser radiation.

[0022] In an alternative embodiment, the functional element already has an active layer due to its manufacturing process, which is divided into at least a first segment and a second segment, preferably further segments. The first surface electrode and the second surface electrode, as well as any additional surface electrodes present, can also be applied separately to the active layer during manufacturing, eliminating the need for subsequent introduction of insulation regions.

[0023] If the active layer has additional regions or segments, the third surface electrode preferably extends completely over the second surface of the additional regions or within the region of the additional segments. In particular, the third surface electrode extends over the entire second surface of the active layer. This ensures that the functional element can be fully utilized and has good optical quality. Any areas not covered by the third surface electrode could result in inhomogeneous optical properties in the affected areas, which could cause irritation to the user.

[0024] The composite pane is designed, for example, as a windshield or a roof pane intended to be part of a vehicle. Alternatively, it is designed, for example, as a partition pane, preferably as a partition pane for a rail vehicle or a bus. Alternatively, the composite pane can be architectural glazing, for example, in the exterior facade of a building or as a partition pane inside a building.

[0025] The terms "outer pane" and "inner pane" arbitrarily describe two different panes. In particular, the outer pane can be referred to as a first pane and the inner pane as a second pane.

[0026] If the composite pane is intended to separate an interior space from the exterior environment in a window opening of a vehicle or building, the term inner pane in the sense of the invention refers to the pane facing the interior (vehicle interior) (second pane). The term outer pane refers to the pane facing the exterior environment (first pane). However, the invention is not restricted to this. The inner pane has a surface facing away from the thermoplastic intermediate layer on the interior side and an outer surface facing the thermoplastic intermediate layer. The surface on the interior side of the inner pane is simultaneously the surface on the interior side of the composite pane. The outer pane has an outer surface facing away from the thermoplastic intermediate layer and an inner surface facing the thermoplastic intermediate layer.The outside surface of the outer pane is also the outside surface of the laminated pane.

[0027] In an advantageous embodiment of a composite pane according to the invention, the thermoplastic intermediate layer contains a polymer, preferably a thermoplastic polymer.

[0028] In a particularly advantageous embodiment of a composite pane according to the invention, the thermoplastic intermediate layer contains at least 3 wt.%, preferably at least 5 wt.%, particularly preferably at least 20 wt.%, even more preferably at least

[0029] 30 wt.% and in particular at least 40 wt.% of a plasticizer. The plasticizer preferably contains or consists of triethylene glycol bis(2-ethylhexanoate).

[0030] Plasticizers are chemicals that make plastics softer, more flexible, more supple and / or more elastic. They shift the thermoelastic range of plastics towards lower temperatures so that the plastics have the desired more elastic properties near the application temperature. Other preferred plasticizers are carboxylic acid esters, particularly low-volatility carboxylic acid esters, fats, oils, plastic resins and camphor. Other plasticizers are preferably aliphatic diesters of tri- or tetraethylene glycol. Particular preference is given to using plasticizers 3G7, 3G8 or 4G7, where the first digit indicates the number of ethylene glycol units and the last digit indicates the number of carbon atoms in the carboxylic acid moiety of the compound. For example, 3G8 stands for triethylene glycol bis(2-ethylhexanoate), i.e. a compound of the formula C4H9CH(CH2CH3)CO(OCH2CH2)3O2CCH(CH2CH3)C4H9.

[0031] In a further particularly advantageous embodiment of a composite pane according to the invention, the intermediate layer contains at least 60% by weight, preferably at least 70% by weight, particularly preferably at least 90% by weight and in particular at least 97% by weight of polyvinyl butyral.

[0032] The thermoplastic intermediate layer can be formed by a single film or by more than one film. The thermoplastic intermediate layer can be formed by one or more thermoplastic films arranged one above the other, with the thickness of the thermoplastic intermediate layer after lamination of the layer stack preferably being between 0.25 mm and 1 mm, typically 0.38 mm or 0.76 mm. If the thickness varies across the surface of the composite pane, the specified values ​​refer to the thickness at the thickest point of the thermoplastic intermediate layer.

[0033] In a preferred embodiment of the invention, the thermoplastic intermediate layer comprises at least a first thermoplastic composite film and a second thermoplastic composite film. The functional element is arranged between the first and second thermoplastic composite films. The first composite film and the second composite film are preferably arranged flat on top of one another and laminated to one another, with the functional element inserted between the two composite films. The regions of the composite films that overlap with the functional element form regions that connect the functional element to the outer pane and the inner pane, thereby fixing the functional element in the composite pane.In other areas of the laminated pane, where the intermediate layers 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.

[0034] Particularly preferably, the thermoplastic intermediate layer also comprises a third thermoplastic composite film arranged circumferentially around the functional element. In other words, the functional element, or more precisely the side surfaces of the functional element, is circumferentially surrounded by the third thermoplastic composite film. The third composite film is frame-like with a recess into which the functional element is inserted. The third composite film can be formed by a thermoplastic film into which the recess has been cut out. Alternatively, the third composite film can also be assembled from several film sections around the functional element.

[0035] The thermoplastic intermediate layer is preferably formed from a total of at least three thermoplastic composite films arranged flat on top of one another, with the middle composite film (third composite film) having a recess in which the functional element is arranged. During production, the third composite film is arranged between the first and second composite films, with the side surfaces of all composite films facing the external environment preferably being arranged in register. The third composite film preferably has approximately the same thickness as the functional element. This compensates for the local thickness difference of the composite pane, which is introduced by the locally limited functional element, so that glass breakage during lamination can be avoided.

[0036] The side surfaces of the functional element visible through the composite pane are preferably arranged flush with the third composite film, so that there is no gap between the side surface of the functional element and the associated side surface of the third composite film. This makes the boundary between the third composite film and the functional element visually less noticeable. In the areas where the surface electrodes protrude from the active layer, the side surface of the functional element refers to the side surface of the active layer, with at least one barrier layer preferably arranged between the side surface of the active layer and the third composite film.

[0037] The thickness of each thermoplastic composite film is preferably from 0.1 mm to 2 mm, more preferably from 0.2 mm to 1 mm.

[0038] In an advantageous development of a composite pane according to the invention, the region of the first and / or second thermoplastic composite film via which the functional element is connected to the outer pane or the inner pane, respectively, is tinted or colored. In other words, at least the region of the first and / or second thermoplastic composite film that coincides congruently with the functional element when viewed through the composite pane is tinted or colored. The transmission of this region in the visible spectral range is therefore reduced compared to a non-tinted or colored layer. The tinted / colored region of the composite film thus reduces the transmission of the composite pane in this region. This can be useful, for example, if the functional element is used as a 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 viewer.

[0039] The tinted or colored area of ​​the first and / or second thermoplastic composite film preferably has a light transmission (according to ISO 9050:2003) 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.

[0040] The thermoplastic intermediate layer can be formed by a single thermoplastic composite film in which the tinted or colored area is created by local tinting or dyeing. Such films are available, for example, by coextrusion. Alternatively, an untinted film section and a tinted or colored film section can be combined to form the thermoplastic intermediate layer.

[0041] In an advantageous embodiment, at least, preferably exclusively, the region of the thermoplastic intermediate layer which is arranged between the functional element and the inner pane and / or the outer pane is tinted. This creates a particularly aesthetic impression when viewed from above onto the inner pane and / or the outer pane. In a preferred embodiment of the invention, at least a section of the circumferential side surface of the active layer is sealed with at least one barrier layer. Preferably, all sections of the circumferential side surface of the active layer are sealed with one or more barrier layers. In addition, regions of the second surface of the active layer, which are preferably free of the third surface electrode, can also be sealed with one or more barrier layers.The barrier layer can partially overlap the edge areas of the third surface electrode, for example, if this is technically feasible. This ensures a particularly secure seal for the active layer of the functional element and particularly good aging resistance of the functional element.

[0042] For the sake of simplicity, in the following we will generally only refer to “the barrier layer”; in the sense of the invention, this may also mean several barrier layers, unless explicitly or implicitly excluded.

[0043] “Sealed” in the context of this invention means that the corresponding section of a surface is completely covered with the barrier layer as a protective layer and is thereby made more resistant and durable, in particular against the diffusion of harmful substances such as moisture, but in particular also against plasticizers from the environment that could otherwise penetrate into the interior of the active layer.

[0044] The barrier layer is preferably in direct and immediate contact with the active layer. For example, there is no separate adhesive or other intermediate layer between the barrier layer and the active layer of the functional element.

[0045] In an advantageous embodiment of the invention, the barrier layer is designed in such a way that it prevents the diffusion of plasticizers from the thermoplastic intermediate layer through the barrier layer.

[0046] The barrier layer is preferably designed such that it prevents the diffusion of plasticizer through the barrier layer to the same or greater extent as the diffusion of plasticizer through the surface electrodes.

[0047] The barrier layer is preferably single-layered or multi-layered, for example, two-layered, three-layered, four-layered, or five-layered. The individual layers of the barrier layer are also referred to below as individual layers and can be made of the same or different materials.

[0048] The individual layer or layers of a multi-layer barrier layer preferably contain a transparent material. For the purposes of the invention, a barrier layer is defined as having a light transmission (according to ISO 9050:2003) in the visible spectral range of greater than 50%, preferably greater than 70%, and in particular greater than 90%. However, for panes or pane sections that are not within the driver's traffic-relevant field of vision, for example, for roof windows or in the upper region of a windshield, or when special darkening is desired, the transmission can also be much lower, for example, greater than 5%. In particular, the barrier layer can be tinted or colored.

[0049] In an advantageous embodiment of the invention, the single layer or the single layers are metal oxide-based, metal nitride-based or metal oxynitride-based, wherein the metal is preferably silicon (Si), aluminum (Al), tantalum (Ta) or vanadium (V) or a mixture thereof.

[0050] The layers containing metal oxide, metal nitride or metal oxynitride can be additionally doped, for example with antimony, fluorine, silver, ruthenium, palladium, aluminum and tantalum.

[0051] In the context of the present invention, the term "based" with respect to the composition of the barrier layer means that the material consists essentially of the metal oxide, metal nitride or metal oxynitride, preferably at least 80 wt. %, particularly preferably at least 90 wt. %, and in particular at least 95 wt. In the case of metal oxides, metal nitrides or metal oxynitrides, which are produced in particular by chemical vapor deposition such as plasma-assisted vapor deposition, the term "based" encompasses the fact that, in addition to the metal oxides, metal nitrides or metal oxynitrides, small amounts of residues of the process gases may also be present, such as carbon and hydrogen as organic residues of organometallic compounds.

[0052] Particularly preferred individual layers are silicon oxide-based, silicon nitride-based, or silicon oxynitride-based. In silicon oxide-based individual layers, the silicon oxide SiOx is preferably substoichiometric, particularly preferably with 1 < x < 2, or stoichiometric (x = 2). However, it can also be superstoichiometric. In an advantageous embodiment of a barrier layer, the barrier layer contains or consists of at least one individual layer of organosilicon of the SiOxCy:H type, where x is preferably from 0.1 to 3 and particularly preferably from 0.2 to 2, and y is preferably greater than 0.3, particularly preferably from 0.3 to 3, and in particular from 0.9 to 2.

[0053] The hydrogen content of the organosilicon compound depends on the degree of polymerization and the chemistry of the deposition processes. The carbon to hydrogen ratio (CuHv) can be arbitrary and is preferably from 1:1000 to 1000:1, particularly preferably from 1:10 to 10:1.

[0054] In an alternative barrier layer, at least one individual layer contains or consists of an organosilicon, wherein the CyHz content of the organosilicon coating is from 20 wt.% to 80 wt.%, preferably from 30 wt.% to 70 wt.%. Such organosilicon coatings are preferably highly cross-linked and have a polymeric character.

[0055] Further preferred individual layers contain or consist of amorphous hydrogenated carbon (aC:H), preferably amorphous hydrogenated nitrogen-doped carbon (a-C:N:H) or amorphous hydrogenated nitrogen- and silicon-doped carbon (a-C:N:Si:H). These are preferably produced by CVD processes using acetylene (C2H2) or acetylene-containing process gases.

[0056] Further preferred individual layers contain other transparent ceramic layers and / or polymer layers that can be produced by gas phase deposition processes and that reduce or substantially prevent the diffusion of plasticizers, for example parylene, polyvinylidene chloride (PVDC), ethylene-vinyl alcohol copolymers (EVOP) or polyacrylates.

[0057] In a particularly advantageous embodiment, the barrier layer contains at least two, preferably exactly two, exactly three, exactly four, or exactly five individual layers of the same material arranged one above the other. This is particularly advantageous for the thin individual layers used here, since defects in one of the individual layers can be compensated for by the additional individual layer(s).

[0058] In a particularly advantageous embodiment, the barrier layer contains precisely one or at least one two-layer layer, also called a double layer or dyad. The double layer preferably consists of a first single layer with a polymeric character and a second single layer with a ceramic or inorganic character. The first single layer is preferably arranged on the side of the double layer facing the functional element. The first single layer of a double layer is particularly preferably arranged directly on the active layer, i.e., the second surface and / or the circumferential side surface.

[0059] In an advantageous embodiment, one or more adhesion-enhancing layers can be arranged between the functional element and the barrier layer. In particular, the peripheral side surface of the active layer of the functional element is subjected to an adhesion-enhancing surface treatment. Thus, the stacking sequence can be exposed to an argon (Ar) plasma, a nitrogen (N2) plasma, or an oxygen (O2) plasma for surface treatment.

[0060] In an advantageous embodiment, the entire barrier layer comprising one or more individual layers has a thickness d (also called material thickness) of 10 nm to 5000 nm (nanometers), preferably from 15 nm to 1000 nm, and particularly preferably from 15 nm to 500 nm. The layer thickness d refers to the thickness of an individual layer or several layers arranged one upon another as a layer sequence, which are applied to a substrate. It is measured in the vertical direction from the surface of the substrate (in this case, the circumferential side surface or second surface of the active layer) to the surface of the applied layer or layer sequence.

[0061] The barrier layers can be produced using any suitable deposition technique. Gas-phase deposition techniques are particularly suitable, as they enable the controlled production of particularly thin barrier layer thicknesses (d).

[0062] The following deposition processes are particularly suitable for the production of barrier layers:

[0063] • Physical vapor deposition (PVD), particularly preferably evaporation, such as thermal evaporation, electron beam evaporation, laser beam evaporation, ion assisted deposition (IAD) or arc evaporation;

[0064] • Sputtering, such as magnetron sputtering. Atomic layer deposition, such as plasma-enhanced atomic layer deposition (PEALD). • Chemical vapor deposition (CVD), particularly preferred is plasma-enhanced chemical vapor deposition (PECVD). Low-pressure PECVD (low-temperature, low-pressure PECVD).

[0065] For functional elements with polymer carrier films and temperature-sensitive active layers, the above-mentioned plasma-assisted processes such as PECVD and PEALD are particularly suitable because they allow deposition at only low substrate temperatures.

[0066] Other barrier layers, also called barrier films, are generally known to those skilled in the art. These can be designed, for example, as disclosed in WO2018188844A1 or WO2019077014A1.

[0067] The controllable functional element comprises an active layer between surface electrodes and is foil-like in design. The active layer has controllable optical properties, which can be controlled via the voltage applied to the surface electrodes.

[0068] The at least first bus bar and the at least second bus bar, as well as any additional bus bars present, are intended to be electrically connected to an external voltage source in a conventional manner. Electrical contact is achieved by suitable connecting cables, for example, foil conductors.

[0069] The surface electrodes, i.e. at least the first, second, and third surface electrodes, are preferably configured as transparent, electrically conductive layers. The surface electrodes preferably contain at least one metal, a metal alloy, or a transparent conductive oxide (TCO). The surface electrodes can contain, for example, silver, gold, copper, nickel, chromium, tungsten, indium tin oxide (ITO), gallium-doped or aluminum-doped zinc oxide, and / or fluorine-doped or antimony-doped tin oxide. The surface electrodes preferably have a thickness of 10 nm to 2 pm, particularly preferably of 20 nm to 1 pm, and most particularly preferably of 30 nm to 500 nm. In addition to the active layer and the surface electrodes, the functional element can have other known layers, for example barrier layers, blocking layers, anti-reflection layers, protective layers, and / or smoothing layers.

[0070] The surface electrodes are preferably applied to a carrier foil. With such a design of the functional element, the surface electrodes and the active layer are arranged between the carrier foils. The carrier foils thus form the surfaces of the functional element. The functional element can thus be provided as a laminated foil, which can be advantageously processed. The functional element is advantageously protected by the carrier foils from damage, in particular corrosion. The functional element contains, in the specified order, at least

[0071] • a first carrier film,

[0072] • the first surface electrode and the second surface electrode,

[0073] • the active layer,

[0074] • the third surface electrode and

[0075] • a second carrier film.

[0076] The first surface electrode and the second surface electrode, as well as any additional surface electrodes, are preferably applied to a single continuous carrier foil, i.e., arranged between the carrier foil and the active layer. The carrier foil thus supports the surface electrodes and provides the necessary mechanical stability to a liquid or soft active layer.

[0077] The first surface electrode, the second surface electrode, the third surface electrode, and / or optionally further surface electrodes can also be formed as an electrically conductive foil, preferably a metallic foil, in particular a foil made of copper or silver. Alternatively, the surface electrodes can be applied to a carrier foil; for example, the surface electrodes can be a coating on a carrier foil.

[0078] The insulation lines, referring to insulation lines between surface electrodes, carrier foils, and / or segments of the active layer, have a width of, for example, 5 pm to 500 pm, in particular 20 pm to 200 pm. The width of the segments, i.e., the distance between adjacent insulation lines, can be selected by a person skilled in the art according to the requirements of the individual case. The insulation lines can be introduced by laser ablation, mechanical cutting, or etching during the production of the functional element. Already laminated functional elements can also be subsequently segmented by laser ablation.

[0079] In an alternative embodiment, the first surface electrode is preferably arranged on a first carrier foil, the second surface electrode is preferably arranged on a second carrier foil, and the third surface electrode is preferably arranged on a third carrier foil. Any additional surface electrodes present are each arranged on an additional carrier foil. The carrier foils preferably have at least the same surface area as the surface electrodes applied to them, but can also have a larger surface area. The first carrier foil and the second carrier foil, as well as any additional surface electrodes present, are preferably separated from one another by an insulating region, particularly preferably by an insulating line.

[0080] The carrier films preferably contain at least one thermoplastic polymer, particularly preferably low-plasticizer or plasticizer-free polyethylene terephthalate (PET). This is particularly advantageous with regard to the stability of the functional element. However, the carrier films can also contain or consist of other low-plasticizer or plasticizer-free polymers, for example, ethylene-vinyl acetate (EVA), 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 0.02 mm to 1 mm, particularly preferably from 0.04 mm to 0.2 mm. Carrier films provide particularly effective protection against the diffusion of plasticizer into the active layer.

[0081] The functional element is preferably a PDLC (polymer dispersed liquid crystal) functional element. The 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 aligned in a disordered manner, 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 in the second region of the active layer and optionally further regions of the active layer align in a common direction, and the transmission of light through the active layer is increased. Alternatively, functional elements, and in particular PDLC functional elements, can be used that are transparent when no voltage is applied (zero volts) and strongly scatter when a voltage is applied.

[0082] In principle, however, it is also possible to use other types of controllable functional elements, for example, electrochromic functional elements or SPD (suspended particle device) functional elements. The controllable functional elements mentioned and their mode of operation are known per se to those skilled in the art, so a detailed description is unnecessary here. A PDLC functional element is particularly preferred, since, especially with PDLC elements, effective protection against plasticizers must be ensured to avoid impairing the optical quality of the functional element.

[0083] The second region of the active layer can change its optical state by applying a voltage to the first busbar and the second busbar. The first region of the active layer is not intended to change its optical state and is therefore preferably designed to be as small as possible. The first region preferably has an area of ​​less than or equal to 10 cm 2 , particularly preferably less than or equal to 2 cm 2 , in particular less than or equal to 1 cm 2 All other regions of the active layer are preferably designed so that they can change their optical state by applying a voltage to the bus bars connected to them.

[0084] The second region of the active layer is larger in its areal extent, preferably at least 5 times larger, particularly preferably at least 10 times larger, in particular at least 100 times larger, than the first region of the active layer.

[0085] Functional elements are commercially available. The functional element is typically cut out of 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 surface is more stable in this case than with mechanical cutting. With mechanically cut side surfaces, there is a risk that the material will shrink back, which is visually noticeable and adversely affects the aesthetics of the pane. 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.

[0086] The electrical control of the functional element of the composite pane according to the invention, installed in a vehicle, is achieved, for example, by means of switches, rotary controls, or sliders integrated into the vehicle's instrumentation. However, a button for controlling the functional element, such as a capacitive button, can also be integrated into the composite pane. Alternatively or additionally, the functional element can be controlled by contactless methods, such as by recognizing gestures, or depending on the condition of the pupil or eyelid as determined by a camera and suitable evaluation electronics. Alternatively or additionally, the functional element can be controlled by sensors that detect light incidence on the pane.

[0087] In an advantageous embodiment of the invention, the bus bars are applied by soldering or gluing to the projecting region of the first surface electrode or the second surface electrode and optionally further surface electrodes. The bus bars applied in this way are preferably in the form of a wire or strip of an electrically conductive foil. The bus bars then contain, for example, at least aluminum, copper, tin-plated copper, gold, silver, zinc, tungsten and / or tin or alloys thereof. The strip preferably has a thickness of 10 μm to 500 μm, particularly preferably of 30 μm to 300 μm. Bus bars made of electrically conductive foils with these thicknesses are technically simple to produce and have an advantageous current-carrying capacity. The strip can be electrically conductively connected to the electrically conductive structure, for example, via a solder compound, via an electrically conductive adhesive, or by direct application.

[0088] Alternatively, the first bus bar and / or the second bus bar and / or the further bus bars that may be present are designed as a printed and fired-in conductive structure. The printed bus bars preferably contain at least one metal, a metal alloy, a metal compound and / or carbon, particularly preferably a noble metal and in particular silver. The printing paste preferably contains metallic particles, metal particles and / or carbon and in particular noble metal particles such as silver particles. The electrical conductivity is preferably achieved by the electrically conductive particles. The particles can be located in an organic and / or inorganic matrix such as pastes or inks, preferably as a printing paste with glass frits. The layer thickness of the printed bus bars is preferably from 5 pm to 40 pm, particularly preferably from 8 pm to 20 pm and most preferably from 8 pm to 12 pm.Printed bus bars with these thicknesses are technically easy to implement and have an advantageous current carrying capacity.

[0089] The specific resistance p a of the first busbar and / or the second busbar and / or any additional busbars present is preferably from 0.8 pOhnrcm to 7.0 pOhnrcm and particularly preferably from 1.0 pOhnrcm to 2.5 pOhnrcm. Busbars with specific resistances in this range are technically simple to implement and have an advantageous current-carrying capacity.

[0090] The first bus bar, the second bus bar and / or any additional bus bars that may be present are preferably applied to a surface of the respective surface electrode that faces the active layer of the functional element. This arrangement is simpler because the surface electrodes are preferably arranged between the active layer and a carrier film and are therefore difficult to connect to a bus bar via the surface of the surface electrode that faces away from the active layer. In principle, however, the first bus bar, the second bus bar and / or any additional bus bars that may be present can also be applied to the surface of the respective surface electrode that faces away from the active layer. For this purpose, a carrier film that may be present can, for example, have a recess via which the bus bar and surface electrode can be connected to one another.

[0091] The first busbar and the second busbar are preferably arranged in opposite edge regions of the functional element or, alternatively, arranged at an angle, i.e., offset substantially 90° from one another. Any additional busbars present are preferably arranged in the same way as the second busbar to the first busbar. If the composite pane is used as a vehicle window in a vehicle, the busbars are preferably arranged such that they are concealed by a masking print of the vehicle window.

[0092] In an advantageous embodiment of the invention, the electrical bridge is designed as a metal foil or metallic wire. The electrically conductive bridge can be applied to the first surface electrode, the third surface electrode, and a portion of the circumferential side surface of the active layer by means of an adhesive layer. The electrically conductive bridge contains, for example, at least aluminum, copper, tin-plated copper, gold, silver, zinc, tungsten, and / or tin, or alloys thereof. The bridge preferably has a thickness of 5 μm to 400 μm, particularly preferably of 40 μm to 250 μm. Electrically conductive bridges with these thicknesses are technically simple to implement and have advantageous current-carrying capacity.The electrically conductive bridge can also be electrically connected to the electrically conductive structure (the first surface electrode and the third surface electrode), for example, via a solder compound, an electrically conductive adhesive, or by direct application. The electrically conductive bridge can, for example, be incorporated into the functional element after the surface electrodes have been connected to the active layer.

[0093] Alternatively, the electrically conductive bridge is formed as a conductive paste. The electrically conductive bridge can, for example, be arranged in an opening in the first region of the active layer, for example a hole-shaped recess in the active layer, thus enabling a direct electrical connection between the first surface electrode and the third surface electrode. The printing paste preferably contains at least one metal, a metal alloy, a metal compound and / or carbon, particularly preferably a noble metal and in particular silver. The electrical conductivity is alternatively achieved by the electrically conductive particles. The particles can be located in an organic and / or inorganic matrix such as pastes or inks, preferably as a printing paste with glass frits. The diameter of the printing paste is preferably at least 5 pm, particularly preferably at least 20 pm and most preferably at least 50 pm.In this arrangement, the electrically conductive bridge is completely enclosed by the active layer and the surface electrodes and is thus well protected from external influences.

[0094] The specific resistance p a The electrically conductive bridge is preferably from 0.8 pOhn / cm to 7.0 pOhn / cm, and particularly preferably from 1.0 pOhn / cm to 2.5 pOhn / cm. Depending on the material of the electrically conductive bridge, it may be advantageous to protect the electrically conductive bridge with a protective layer, for example a lacquer or a polymer film.

[0095] The first bus bar is preferably electrically connected to the first surface electrode using an electrically conductive material containing silver; more preferably, the material is silver-based. The second bus bar is preferably electrically connected to the second surface electrode using an electrically conductive material, preferably silver-based. It goes without saying that any additional bus bars that may be present are also connected to additional surface electrodes, preferably using an electrically conductive material, preferably silver-based. The electrically conductive material is applied at least, preferably exclusively, between the bus bar and the projecting region of the surface electrode to which the bus bar is connected.This arrangement can be manufactured quickly and easily, with silver-containing materials being characterized by high electrical conductivity and relatively long-term stability.

[0096] If something is "based" on a material, it consists predominantly of that material, in particular essentially of that material along with any impurities or dopants. Unless otherwise stated, the specification of layer thicknesses refers to the geometric thickness of a layer.

[0097] The composite pane with an electrically controllable functional element can advantageously be designed as a windshield with a functional element as an electrically controllable sun visor. Such a windshield has an upper edge and a lower edge, as well as two side edges running between the upper and lower edges. The upper edge refers to the edge that is intended to point upwards in the installed position. The lower edge refers to the edge that is intended to point downwards in the installed position. The upper edge is often also referred to as the roof edge, and the lower edge is referred to as the engine edge.

[0098] Windshields have a central field of vision, the optical quality of which must meet stringent requirements. This central field of vision must exhibit high light transmission (according to ISO 9050:2003) (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.

[0099] The functional element is then advantageously 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 upper 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 upper 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.

[0100] The functional element is preferably arranged across the entire width of the laminated pane or windshield, 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 laminated pane and protected from contact with the surrounding atmosphere and corrosion.

[0101] The upper edge and the adjacent side surface, or all side surfaces, of the functional element are preferably concealed by an opaque masking print or an outer frame when viewed through the laminated glass. Windshields and vehicle roof windows typically have a peripheral masking print made of opaque enamel, which serves in particular to protect the adhesive used to install the windshield from UV radiation and to visually conceal it. This peripheral masking print is preferably used to conceal the upper edge and side surface of the functional element, as well as the necessary electrical connections, including the bus bars. The functional element is then advantageously integrated into the appearance of the laminated glass, and only the lower edge is potentially visible to the observer.Preferably, both the outer pane and the inner pane have a masking print so that visibility is prevented from both sides.

[0102] The functional element can also have recesses or holes, for example in the area of ​​so-called sensor windows or camera windows of the laminated pane, especially the windshield. These areas are intended to be equipped with sensors or cameras whose function would be impaired by a controllable functional element in the beam path, for example rain sensors. It is also possible to realize the functional element-free windows with at least two separate functional elements, with a gap between the functional elements that provides space for sensor or camera windows. The outer pane and the inner pane are preferably made of glass, particularly preferably of soda-lime glass, as is common for window panes.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.

[0103] 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).

[0104] The thickness of the outer and inner panes can vary widely and thus be adapted to the requirements of each individual case. The outer and inner panes preferably have thicknesses of 0.5 mm to 5 mm, particularly preferably 1 mm to 3 mm.

[0105] Furthermore, the invention extends to a glazing unit comprising the composite pane according to the invention. The first busbar and the second busbar, as well as optionally further busbars, are connected to a voltage source in such a way that different optical states of the second region of the active layer can be controlled by means of electrical voltage changes at the busbars. If present, different optical states can also be controlled in other regions of the active layer by means of electrical voltage changes at the busbars. The voltage changes at the busbars can be generated by the voltage source. The busbars can be connected to the voltage source by conventional means. The electrical contact is preferably realized by suitable connecting cables, for example foil conductors.

[0106] The invention also extends to a method for producing a composite pane. The method comprises the following steps in the specified order: a) In a first step, the first busbar is connected to the first surface electrode of the functional element, and the second busbar is connected to the second surface electrode of the functional element. b) In a second step, the functional element is arranged together with the outer pane, the inner pane, and the thermoplastic intermediate layer to form a layer stack and laminated to form a composite pane.

[0107] In an advantageous development of the method according to the invention, the thermoplastic intermediate layer in method step b) comprises a first thermoplastic composite film, a second thermoplastic composite film and a third thermoplastic composite film, wherein the functional element is arranged between the first thermoplastic composite film and the second thermoplastic composite film and the third thermoplastic composite film is arranged such that it surrounds the functional element, for example like a frame.

[0108] In an advantageous development of the method according to the invention, in a method step prior to the first method step a), the active layer of the functional element is divided into the first segment and the second segment by means of segmentation by laser radiation.

[0109] The electrical contacting of the bus bars is preferably carried out before the laminated pane is laminated.

[0110] Any existing prints, for example opaque cover prints or printed bus bars for electrical contact with the functional element, are preferably applied using the screen printing process.

[0111] Lamination is preferably carried out under the influence of heat, vacuum, and / or pressure. Known lamination processes can be used, for example, autoclave processes, vacuum bag processes, vacuum ring processes, calender processes, vacuum laminators, or combinations thereof.

[0112] The invention further encompasses the use of a composite pane according to the invention with an electrically controllable functional element as interior glazing or exterior glazing in a vehicle, preferably as a windshield or roof pane of a vehicle, or a building, wherein the electrically controllable functional element is used as a sunshade, sun visor, or privacy screen, preferably as a sun visor. The invention further encompasses the use of the composite pane according to the invention as a windshield or roof pane of a vehicle.

[0113] The invention further encompasses the use of the electrically controllable functional element as a sun visor in a windshield or roof window of a vehicle, wherein the functional element comprises an active layer having a first surface, a second surface, and a circumferential side surface, a first surface electrode extending over the first surface in a first region of the active layer, and a second surface electrode extending over the first surface in a second region of the active layer. Furthermore, the functional element comprises a third surface electrode extending over the second surface at least in the first and second regions of the active layer, and an electrical bridge electrically connecting the first surface electrode to the third surface electrode.The first surface electrode also has a region projecting from the first active layer, and the second surface electrode has a second region projecting from the active layer. A first bus bar is also arranged at least on the first projecting region, and a second bus bar is arranged at least on the second projecting region. The first surface electrode and the second surface electrode are electrically insulated from one another.

[0114] The invention is explained in more detail with reference to the drawings. The drawings are schematic representations and are not to scale. The drawings do not limit the invention in any way. They show:

[0115] Figure 1 shows an embodiment of the functional element with bus bars as it would be installed in the composite pane according to the invention in a plan view of the second surface of the functional element,

[0116] Figure 2 shows the functional element from Figure 1 in a side view of a first section of the circumferential side surface of the functional element,

[0117] Figure 3 shows the functional element from Figure 1 in a further side view of a further section of the circumferential side surface of the functional element,

[0118] Figure 4 shows an embodiment of the composite pane according to the invention in a plan view, Figure 5 shows a cross-sectional view of the composite pane according to the invention from Figure 4, Figure 6 shows a further embodiment of the composite pane according to the invention in a plan view,

[0119] Figure 7 is a cross-sectional view of the composite pane according to the invention from Figure 6 and Figure 8 is a side view of a functional element as used in the composite pane from Figures 6 and 7.

[0120] Figures 1, 2, and 3 each show a detail of a functional element 4 with electrically controllable optical properties, such as could be a component of a composite pane 100 according to the invention. Figure 1 shows a plan view of the functional element 4, with Figures 2 and 3 each showing a side view of the circumferential side surface of the functional element 4. The functional element 4 has an active layer 5 with a first surface A, a second surface B, and a circumferential side surface S. Figure 2 shows a side view showing a plan view of a second section S" of the circumferential side surface S of the active layer 5. Figure 3 shows a side view offset by 90° from the side view in Figure 2. The viewing direction from which the functional element 4 is viewed in Figure 3 is indicated by a dashed arrow in Figure 1. The controllable functional element 4 is, for example, a PDLC multilayer film.

[0121] The active layer 5 is divided into a first segment 5.1 and a second segment 5.2. A first surface electrode 6.1 is applied to the first surface A of the active layer 5 in the region of the first segment 5.1. A second surface electrode 6.2 is applied to the first surface A of the active layer 5 in the region of the second segment 5.2. A third surface electrode 6.3 is applied to the second surface B of the active layer 5. The third surface electrode 6.3 extends over the entire second surface B of the active layer 5. The first surface electrode 6.1 and the second surface electrode 6.2 together extend over the entire first surface A of the active layer 5. An electrical bridge 7 electrically connects the first surface electrode 6.1 to the third surface electrode 6.3.

[0122] In Figure 1, a linear insulation region, which separates the first surface electrode 6.1 from the second surface electrode 6.2 and the first segment 5.1 of the active layer 5 from the second segment 5.2 of the active layer 5, is indicated by a dashed line. In Figure 2, the linear insulation region between the first surface electrode 6.1 and the second surface electrode 6.2 as well as the first segment 5.1 and the second segment 5.2 is represented by a visible gap. The linear insulation region, also called insulation line, serves for electrical insulation in the case of the first surface electrode 6.1 and the second surface electrode 6.2, so that both electrodes are arranged electrically insulated from one another. In the case of the segmented active layer 5, the insulation line serves to improve the optical quality of the functional element 4. The insulation line between the surface electrodes 6.1, 6.2 and the segments 5.1, 5.2 has been introduced into the functional element 4, for example, by laser ablation. The insulation lines have a width of 50 pm, for example.

[0123] The active layer 5 also has the circumferential side surface S, which runs between the first surface A and the second surface B. In a first section S' of the circumferential side surface S of the active layer 5, 5.1, the first surface electrode 6.1 projects beyond the active layer 5, 5.1 (see Figure 2), such that the first surface electrode 6.1 has a projecting region U' relative to the active layer 5. In a second section S" of the circumferential side surface S of the active layer 5, 5.2, the second surface electrode 6.2 projects beyond the active layer 5, 5.2 (see Figure 3), such that the second surface electrode 6.2 has a projecting region II" relative to the active layer 5. The projection u of the first surface electrode 6.1 relative to the active layer 5 and the projection u of the second surface electrode 6.2 relative to the active layer 5 are each, for example, 3 mm.The projection u is measured here and in the following by the distance of the outer projecting edge of the surface electrode to the edge of the active layer 5 (distance measured orthogonal to the section of the side surface S in which the surface electrode projects).

[0124] A first bus bar 8.1 is applied to the protruding region U' of the first surface electrode 6.1 and a second bus bar 8.2 is applied to the protruding region II" of the second surface electrode 6.2. The bus bars 8.1, 8.2 are each applied to the surface of the surface electrodes 6.1, 6.2 facing the active layer 5. The protruding region U' of the first surface electrode 6.1 is offset by 90° to the protruding region II" of the second surface electrode 6.2. The bus bars 8.1, 8.2 are therefore not opposite one another, but rather also offset by 90° to one another. The bus bars 8.1, 8.2 are designed, for example, as a silver-containing printing paste with a layer thickness of 10 pm. The first surface electrode 6.1 and the third surface electrode 6.3 are electrically connected to one another via an electrically conductive bridge 7.The electrically conductive bridge 7 is arranged in a hole-shaped recess of the first segment 5.1 of the active layer 5 and is in direct spatial contact with the first surface electrode 6.1 and the third surface electrode 6.3, so that a voltage applied to the first surface electrode 6.1 is also applied to the third surface electrode 6.3 via the electrically conductive bridge 7. Alternatively, the electrically conductive bridge 7 can be arranged along the side surface S of the active layer 5 and touch the first surface electrode 6.1 and the third surface electrode 6.3 in an edge region (not shown here).

[0125] The first bus bar 8.1 and the second bus bar 8.2 are connected to the voltage source 10 via connecting lines. The voltage source 10 is in turn connected to a control unit, via which the voltage intended for the functional element 4 can be set.

[0126] The surface electrodes 6.1, 6.2, 6.3 are each applied to a carrier film (carrier film not shown here), which has essentially the same surface area as the respective applied surface electrode 6.1, 6.2, 6.3. The carrier films are provided with an ITO coating with a thickness of approximately 100 nm facing the active layer 5, which forms the surface electrodes 6.1, 6.2, 6.3. The surface electrodes 6.1, 6.2, 6.3 are therefore arranged between a carrier film and the active layer 5. The carrier films are not shown in the figures. The carrier films consist, for example, of polyethylene terephthalate (PET) and have a thickness of, for example, 0.125 mm. The surface electrodes 6.1, 6.2, 6.3 are arranged between the respective carrier film and the active layer 5.

[0127] The active layer 5 contains a polymer matrix with liquid crystals dispersed therein, which align themselves depending on the electrical voltage applied to the surface electrodes 6.1, 6.2, 6.3, thereby allowing the optical properties to be controlled. The second segment 5.2 of the active layer 5 changes its optical state depending on the voltage applied to the first surface electrode 6.1 and the second surface electrode 6.2. The optical change is caused by the voltage difference between the second surface electrode 6.2 and the third surface electrode 6.3, which causes the liquid crystals in the second segment 5.2 to realign.

[0128] Figures 4 and 5 show an embodiment of the composite pane 100 according to the invention, wherein a functional element 4 is arranged within the composite pane 100, essentially as described for Figures 1 to 3. The composite pane 100 is designed as a windshield with an electrically controllable sun visor for a vehicle, and the functional element 4 is tailored and curved (or bendable) according to the arrangement in the windshield. Figure 4 shows a plan view of an inner side of the composite pane 100, i.e., that surface of the composite pane 100 which is intended to face the interior of a vehicle. Figure 5 shows a cross-sectional view of the composite pane 100 from Figure 4, wherein the section line XX' is indicated in Figure 4.

[0129] The composite pane 100 comprises an outer pane 1 and an inner pane 2, which are connected to each other via a thermoplastic intermediate layer 3. The outer pane 1 has a thickness of 2.1 mm and is made, for example, of clear soda-lime glass. The inner pane 2 has a thickness of 1.6 mm and is also made, for example, of clear soda-lime glass. The composite pane has an upper edge D facing the roof in the installed position and a lower edge M facing the engine compartment in the installed position.

[0130] The outer pane 1 has an interior-side surface II facing the thermoplastic intermediate layer 3 and an exterior-side surface I facing away from the thermoplastic intermediate layer 3. The exterior-side surface I of the outer pane 1 is also the exterior surface of the composite pane 100. The inner pane 2 has an exterior-side surface III facing the thermoplastic intermediate layer 3. Furthermore, the inner pane 2 has an interior-side surface IV facing away from the thermoplastic intermediate layer 3, which is also the interior-side surface of the composite pane 100.

[0131] The thermoplastic intermediate layer 3 comprises a first thermoplastic composite film 3.1, a second thermoplastic composite film 3.2, and a third thermoplastic composite film 3.3, which are arranged stacked one above the other between the outer pane 1 and the inner pane 2, the third thermoplastic composite film 3.3 being arranged between the first and the second thermoplastic composite film 3.1, 3.2. The composite films 3.1, 3.2, 3.3 each have a thickness of 0.38 mm, for example. The composite films 3.1, 3.2, 3.3 consist, for example, of 78 wt.% polyvinyl butyral (PVB) and 22 wt.% 2,2'-ethylenedioxydiethylbis(2-ethylhexanoate) as a plasticizer.

[0132] The functional element 4, whose optical properties can be controlled by an electrical voltage, is arranged between the first thermoplastic composite film 3.1 and the second thermoplastic composite film 3.2. The electrical leads are not shown for the sake of simplicity. The first thermoplastic composite film 3.1 is connected to the outer pane 1, and the second thermoplastic composite film 3.2 is connected to the inner pane 2. The third thermoplastic composite film 3.3 located between them has a cutout into which the cut functional element 4 is inserted with a precise fit, i.e., flush on all sides of the active layer 5. The overhang U', II" of the first surface electrode 6.1 and the second surface electrode 6.2 can overlap with the third thermoplastic composite film 3.3 (not shown here). The third composite film 3.3 thus forms a kind of passepartout for the functional element 4, which is thus completely encapsulated in thermoplastic material and thus protected.

[0133] The functional element 4 serves as a sun visor in the composite pane 100 designed as a windshield and is arranged in an area above a central viewing area B (as defined in ECE-R43). The height of the sun visor is, for example, 21 cm.

[0134] The first composite film 3.1 can have a tinted area arranged between the functional element 4 and the outer pane 1 (not shown here). This further reduces the light transmission of the windshield in the area of ​​the functional element 4 (for example, a light transmission of 30% in the tinted area) and softens the milky appearance of the PDLC functional element 4 in the diffused state. This significantly improves the aesthetics of the windshield.

[0135] The composite pane 100, as is usual for windshields, has a circumferential peripheral masking print 11 formed by an opaque enamel on the interior-side surfaces II, IV of the outer pane 1 and the inner pane 2. The distance of the functional element 4 to the upper edge D and the side edges of the composite pane 100 is smaller than the width of the masking print 11, so that the side surfaces of the functional element 4 - with the exception of the side edge facing the central field of vision B - are covered by the masking print 11. The electrical connections (not shown), including the bus bars 8.1, 8.2, are also expediently attached in the area of ​​the masking print 11 and thus hidden.

[0136] The functional element 4 has a barrier layer 9 on all side surfaces, which covers the entire circumferential side surface and the circumferential edge region of the top side (i.e. the surface facing the first thermoplastic composite film 3.1) of the functional element 4. The top side of the functional element 4 is simultaneously the second surface B of the active layer 5 covered by the third surface electrode 6.3 (see Figures 1 to 3). Preferably, the functional element 4 is also covered in the edge regions of the bottom side (i.e. the surface facing the second thermoplastic composite film 3.2) with a barrier layer 9, which does not have a projecting region U', U" through the first or second surface electrode 6.1, 6.2 (not shown here). The bottom side of the functional element 4 is simultaneously the first surface A of the active layer 5 covered by the first and second surface electrodes 6.1, 6.2 (see Figures 1 to 3).The term “circumferential side surface of the functional element 4” essentially refers to the circumferential side surface S of the active layer 5, as shown in Figures 1 to 3.

[0137] The barrier layers 9 reduce or prevent the diffusion of plasticizer into the active layer 5, which increases the lifetime of the functional element 4. The thickness (or in other words, the material thickness) of the barrier layers 9 is, for example, at least 50 nm. The barrier layers 9 are, for example, an organosilicon layer. The barrier layers can also be formed by multilayered individual layers.

[0138] Figure 6 shows a plan view of a further embodiment of the composite pane 100 according to the invention. Figure 7 shows a cross-sectional view of the composite pane 100 from Figure 6, with the section line XX' indicated in Figure 6. The composite pane 100 is designed as a roof pane for a vehicle. The functional element 4 is arranged between an outer pane 1 and an inner pane 2 within a thermoplastic intermediate layer 3. The functional element 4 is arranged between a first thermoplastic composite film 3.1 and a second thermoplastic composite film 3.2. A third thermoplastic composite film 3.3 is arranged in a frame-like manner around the functional element 4. The composite pane 100 has, as is usual for roof panes, a circumferential peripheral cover print 11 which is formed by an opaque enamel on the interior-side surfaces II, IV of the outer pane 1 and the inner pane 2.

[0139] The optical properties of the functional element 4 can be controlled by an electrical voltage. The electrical supply lines are not shown for the sake of simplicity. The functional element 4 is divided into several switchable regions 5.2, 5'; for more details, please refer to Figure 8. The peripheral edge of the functional element 4 is completely covered by the cover print 11, including the bus bars 8.1, 8.2, 8'. The functional element 4 extends essentially over the entire surface of the composite pane 100, less a peripheral edge region which is completely covered by the cover print 11. In other words, the functional element 4 extends over the entire see-through area of ​​the composite pane 100. The functional element 4 has a barrier layer 9 on all side surfaces, which barrier layer covers the entire peripheral side surface and the peripheral edge region of the upper side (i.e. that of the first thermoplastic composite film 3.1 facing surface) of the functional element 4. The upper side of the functional element 4 is simultaneously the second surface B of the active layer 5 covered by the third surface electrode 6.3 (see Figure 8). The functional element 4 does not have a barrier layer 9 on its underside (i.e. the surface facing the second thermoplastic composite film 3.2) because the first surface electrode 6.1, the second surface electrode 6.2 and all further surface electrodes 6' have a projecting area U', U", U"' to the active layer 5, whereby a projection is achieved along the entire circumferential edge of the active layer 5 and the use of a barrier layer 9 is no longer necessary (not shown here). The underside of the functional element 4 is simultaneously the first surface A of the active layer 5 covered by the first and second surface electrodes 6.1, 6.2 (see Figure 8).The term “circumferential side surface of the functional element 4” essentially refers to the circumferential side surface S of the active layer 5, as shown in Figure 8.

[0140] The outer pane 1 and the inner pane 2 are made of soda-lime glass, which can optionally be tinted. The outer pane 1 has a thickness of 2.1 mm, for example, and the inner pane 2 has a thickness of 1.6 mm. The thermoplastic composite films 3.1, 3.2, and 3.3 each have a thickness of 0.38 mm, for example, and consist of, for example, 78 wt.% polyvinyl butyral (PVB) and 22 wt.% 2,2'-ethylenedioxydiethylbis(2-ethylhexanoate) as a plasticizer.

[0141] Figure 8 shows the functional element 4 in a side view, which in the embodiment of Figures 6 and 7 is a component of the composite pane 100. The variant of the functional element 4 shown in Figure 8 essentially corresponds to the variant from Figures 1 to 3, so that only the differences will be discussed here, and otherwise reference is made to the description of Figures 1 to 3.

[0142] In contrast to the functional element 4 from Figures 1 to 3, in addition to the first surface electrode 6.1 and the second surface electrode 6.2, further surface electrodes 6' are applied to the first surface A of the active layer 5. A total of 5 electrically insulated surface electrodes 6.1, 6.2, 6' are applied to the first surface A of the active layer 5. The second surface electrode 6.2 and the further 3 surface electrodes 6' are arranged next to one another in a strip shape on the active layer 5, so that essentially rectangular-shaped regions can be seen in plan view 4 (see Figure 6). The surface electrodes 6.2, 6' are each arranged parallel to one another and next to one another, with the longer sides of the individual surface electrodes 6', 6.2 facing one another. The surface electrodes 6.1, 6.2, 6' are separated from one another by insulation lines, for example introduced by laser ablation.The insulation lines, for example, have a width of 50 pm.

[0143] In contrast to the functional element 4 from Figures 1 to 3, here the active layer 5 is not divided into individual segments, i.e. regions separated from one another by an insulating region. The entire active layer 5 is a continuous layer, which, however, can nevertheless be divided into a first region 5.1, a second region 5.2 and three further regions 5' due to the divided surface electrodes 6.1, 6.2, 6' on the first surface A. In the second region 5.2 and the further regions 5', different optical states can be controlled by applying a voltage by means of the voltage source 10 to the first surface electrode 6.1 and the second surface electrode 6.2 as well as the further surface electrodes 6'. The second region 5.2 and the further regions 5' can be switched independently of one another, whereby the active layer 5 can be in different optical states depending on the region 5.2, 5'. The first region 5.1 of the active layer 5 is not switchable and is preferably covered by the cover print 11 when installed in the composite pane 100.

[0144] The first surface electrode 6.1, the second surface electrode 6.2 and the further surface electrodes 6' are connected to a busbar 8.1, 8.2, 8' in a region LT, II", U"' projecting towards the active layer 5 (shown only for the first surface electrode 6.1 in Figure 8). The busbars 8.1, 8.2, 8' are applied to the surface of the respective surface electrode 6.1, 6.2, 6' facing the active layer 5. The busbars 8.1, 8.2, 8' are in turn connected to the voltage source 10 by means of electrical lines. Taken together, the first surface electrode 6.1, the second surface electrode 6.2 and the further surface electrodes 6' project towards the active layer 5 along the entire circumferential side surface S, minus the linear insulation region. This protects the functional element 4 even better against the influence of plasticizers, for example from the PVB layer, which would impair the optical quality of the functional element 4.List of reference symbols:.

[0145] 1 outer pane

[0146] 2 inner pane

[0147] 3 thermoplastic intermediate layer

[0148] 3.1 first thermoplastic composite film of the intermediate layer 3

[0149] 3.2 second thermoplastic composite film of the intermediate layer 3

[0150] 3.3 third thermoplastic composite film of the intermediate layer 3

[0151] 4 Functional element

[0152] 5 active layer

[0153] 5.1 first segment / first area of ​​the active layer 5

[0154] 5.2 second segment / second area of ​​the active layer 5

[0155] 5' further segments / further areas of the active layer 5

[0156] 6.1 first surface electrode

[0157] 6.2 second surface electrode

[0158] 6.3 third surface electrode

[0159] 6' additional surface electrodes

[0160] 7 electric bridge

[0161] 8.1 first collection manager

[0162] 8.2 second collection manager

[0163] 8' additional collection ladder

[0164] 9 Barrier layer

[0165] 10 Voltage source

[0166] 11 Cover print

[0167] 100 composite panes

[0168] I outside surface of the outer pane 1

[0169] II Interior surface of the outer pane 1

[0170] III outer surface of the inner pane 2

[0171] IV Interior surface of the inner pane 2

[0172] A first surface of the active layer 5

[0173] B second surface of the active layer 5

[0174] S circumferential side surface of the active layer 5

[0175] S' first section of the side surface S

[0176] S“ second section of the side surface S

[0177] U' protruding area of ​​the first surface electrode 6.1 II" protruding area of ​​the second surface electrode 6.2

[0178] U“' protruding area of ​​another surface electrode 6'

[0179] XX' section line H central field of view of the laminated glass 100 as windshield

[0180] D Top edge of the composite pane 100, roof edge

[0181] M Lower edge of the composite pane 100, motor edge

Claims

Patent claims 1. A composite pane (100) with electrically controllable optical properties, comprising: an outer pane (1), a thermoplastic intermediate layer (3), an inner pane (2) and a functional element (4) with electrically controllable optical properties arranged between the outer pane (1) and the inner pane (2), wherein the functional element (4) comprises: an active layer (5) with a first surface (A), a second surface (B) and a circumferential side surface (S), a first surface electrode (6.1) which extends over the first surface (A) in a first region (5.1) of the active layer (5), a second surface electrode (6.2) which extends over the first surface (A) in a second region (5.2) of the active layer (5), a third surface electrode (6.3) which extends at least in the first and second regions (5.1, 5.2).2) of the active layer (5) extends over the second surface (B) and an electrical bridge (7) which electrically connects the first surface electrode (6.1) to the third surface electrode (6.3), wherein the first surface electrode (6.1) has a first projecting region (U') towards the active layer (5) and the second surface electrode (6.2) has a second projecting region (LT) towards the active layer (5), and a first bus conductor (8.1) is arranged at least on the first projecting region (U') and a second bus conductor (8.2) is arranged at least on the second projecting region (LT), and wherein the first surface electrode (6.1) and the second surface electrode (6.2) are electrically insulated from one another.

2. Composite pane (100) according to claim 1, wherein the active layer (5) has a first segment (5.1) in the first region and a second segment (5.2) in the second region.

3. Composite pane (100) according to claim 1 or 2, wherein the first projecting region (U') and the second projecting region (LT) together project beyond the active layer (5) along the entire circumferential side surface (S).

4. Composite pane (100) according to one of claims 1 to 3, wherein the thermoplastic intermediate layer (3) comprises at least a first thermoplastic composite film (3.1) and a second thermoplastic composite film (3.2) and the functional element (4) is arranged between the first and the second thermoplastic composite film (3.1, 3.2).

5. Composite pane (100) according to claim 4, wherein the thermoplastic intermediate layer (3) has a third frame-shaped thermoplastic composite film (3.3) which is arranged circumferentially around the functional element (4).

6. Composite pane (100) according to one of claims 1 to 5, wherein the active layer (5) is sealed with at least one barrier layer (9) on at least one section (S', S") of the circumferential side surface (S), preferably on all sections of the circumferential side surface (S).

7. Composite pane (100) according to one of claims 1 to 6, wherein the functional element (4) is a PDLC functional element.

8. Composite pane (100) according to one of claims 1 to 7, wherein the second region (5.2) is at least 5 times larger, particularly preferably at least 10 times larger, in its surface area than the first region (5.1).

9. Composite pane (100) according to one of claims 1 to 8, wherein the first surface electrode (6.1) and / or the second surface electrode (6.2) protrude at least 1 mm, preferably at least 5 mm, from the active layer (5).

10. Composite pane (100) according to one of claims 1 to 9, wherein the first busbar (8.1) is electrically connected to the first surface electrode (6.1) by means of an electrically conductive material, preferably a silver-containing material.

11. Glazing unit comprising a composite pane (100) according to one of claims 1 to 10, wherein the first and second busbars (8.1, 8.2) are connected to a voltage source (10) and different optical states of the second region (5.2) can be controlled by means of electrical voltage changes.

12. A method for producing a composite pane (100) according to any one of claims 1 to 10, wherein a) the first bus bar (8.1) is connected to the first surface electrode (6.1) of the functional element (4) and the second bus bar (8.2) is connected to the second surface electrode (6.2) of the functional element (4) and b) the functional element (4) is arranged together with the outer pane (1), the inner pane (2) and the thermoplastic intermediate layer (3) to form a layer stack and the layer stack is then laminated to form a composite pane (100).

13. The method according to claim 12, wherein the division of the active layer (5) into the first segment (5.1) and the second segment (5.2) is carried out by means of segmentation by laser radiation.

14. Use of a composite pane (100) according to one of claims 1 to 10 as a windshield or roof pane of a vehicle.

15. Use according to claim 14, wherein the electrically controllable functional element (4) is used as a sun visor in a windshield or roof pane of a vehicle.

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