WO2024223401A1 - Composite pane having electrically controllable optical properties - Google Patents

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

composite pane with electrically controllable optical properties

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.

In the automotive and construction sectors, composite panes with electrically controllable functional elements are often used for sun protection or privacy. 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 composite pane or glued to it. In the case of windshields, for example, the driver can control the transmission behavior of the pane himself with regard to solar radiation. This means that a conventional mechanical sun visor can be dispensed with. This reduces the weight of the vehicle and saves 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.

Windshields with such electrically controllable sun visors are known, for example, from DE102013001334A1, DE102005049081 B3,

DE102005007427A1 and DE102007027296A1.

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 aligned in a disordered manner, which leads to a strong scattering of the light passing through the active layer. If a voltage is applied to the surface electrodes, the liquid crystals align in a common direction and the transmission of light through the active layer is increased. The PDLC functional element works less by reducing the overall transmission, but by increasing the scattering in order to ensure glare protection. PDLC functional elements are known, for example, from US20150301367A1. A problem with laminated functional elements arises from the penetration of gas and the diffusion of plasticizers or other harmful compounds into the functional element. The substances often penetrate through the poorly protected side surfaces of the functional element, which often leads to undesirable signs of aging, such as lightening and changes in shading. These problems occur particularly with PDLC functional elements.

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. W02019077014A1 and WO2018188844A1 disclose composite panes with a functional element, wherein the functional element is protected against the penetration of plasticizer from the thermoplastic intermediate layer by means of several barrier layers on the side surface.

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.

The object of the present invention is achieved by a composite pane according to independent claim 1. Preferred embodiments emerge from the subclaims.

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 which has a first surface, a second surface and a peripheral side surface, a first surface electrode, a second surface electrode, a third surface electrode and an electrical bridge which 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.

The active layer and the surface electrodes are designed like foils and form a stacking sequence. Foils typically have a large surface area but only a small total thickness. In the following, the large surfaces of the stacking sequence that limit the stacking sequence are referred to as the upper surface and lower surface and the orthogonal surfaces that have only a small width (corresponding to the direction of the small total 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.

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, minus an insulation region, for example an insulation line, which is arranged between the first and the second surface electrode.

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 essentially congruently with the first surface electrode and the second segment of the active layer is arranged essentially congruently with the second surface electrode. The appearance of the functional element is improved by dividing the active layer into segments. 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 protruding region from the active layer and the second surface electrode has a second protruding region from the active layer. A first bus bar is arranged at least on the first protruding region and a second bus bar is arranged at least on the second protruding region. The first surface electrode and the second surface electrode are electrically insulated from one another. In other words: the first surface electrode protrudes beyond the active layer in a first section of the circumferential side surface and the second surface electrode protrudes beyond the active layer in a second section of the circumferential side surface. A first bus bar is arranged at least on the protruding region of the first surface electrode and a second bus bar is arranged at least on the protruding region of the second surface electrode. The first surface electrode and the second surface electrode are arranged electrically insulated from one another. The first surface electrode is preferably separated from the second surface electrode by an insulation line, which was introduced, for example, by means of laser ablation.

In the sense of the invention, the “circumferential side surface of the active layer” means the outer circumferential surface which extends perpendicular to the first surface and the second surface of the active layer. The first and the second surfaces of the active layer are the main surfaces of the active layer, which are arranged essentially 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, minus those sections of the circumferential side surface of the segments which do not run along the edge of the functional element. In the sense of the invention, this means that all sections of the circumferential side surface of the first segment which face the circumferential side surface of the second segment (or any other segment of the active layer) 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 which face the circumferential side surface of the first segment (or any other segment of the active layer).

By “the first surface of the active layer” is meant, if the active layer is divided into segments, the first surface of the first segment and the first surface of the second segment as well as the first surface of any further segments of the active layer. It is understood that “the second surface of the active layer” in the sense 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 surface of the individual segments are arranged next to one another so that, in a plan view of the composite pane, the first surface of the individual segments is 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 is also necessarily facing 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 therefore 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 therefore 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.

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.

A great advantage of the invention is that the solution according to the invention allows the surface electrodes with busbars to be arranged on only one surface of the active layer, which provides creative freedom when producing the composite pane. According to the generic principle, a first busbar must be connected to a surface electrode on the first surface of the active layer and a second busbar must be connected to a surface electrode on the second surface of the active layer, which results in a larger space requirement, which does not meet the desired properties of the Composite pane. In addition, production is significantly more complex because the functional element has to 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 bus bar in a region of the first surface electrode that protrudes from the active layer and the second surface electrode is connected to the second bus bar in a region of the second surface electrode that protrudes 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 to prevent the diffusion of pollutants 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 change the optical properties of the functional element in an undesirable way. The aging leads, for example, to a lightening or change in the transmission of the functional element, starting at its side edges.

In a preferred embodiment of the invention, the first surface electrode, the second surface electrode and any other surface electrodes that are applied to the first surface of the active layer together protrude along the entire circumferential side surface of the active layer. This means that the surface electrodes, minus one or more insulation regions that are arranged between the surface electrodes, protrude 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). The largely uninterrupted projection of the surface electrodes along the circumferential side surface of the active layer protects the active layer very effectively against the diffusion of pollutants. In this way, fewer barrier layers are required, which saves material costs and minimizes the process effort. Preferably, the first protruding region and the second protruding region together protrude beyond the active layer along the entire circumferential side surface.

Preferably, the first surface electrode and/or the second surface electrode 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 other surface electrodes present have a projection u of at least 1 mm, particularly preferably of at least 5 mm from the active layer. In the sense of the invention, the projection is determined by the distance of the outer edge of the surface electrode to the outer edge of the active layer in the projecting area. This means the distance orthogonal to the side surface of the active layer. If the projection is variable over the entire functional element, then the projection u is preferably at least 1 mm on average, particularly preferably at least 5 mm. From a projection with the dimensions mentioned, busbars can be connected to the surface electrode in a simplified process.

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 peripheral side surface of the active layer. Each further surface electrode is preferably electrically connected to exactly one further busbar, wherein the further surface electrodes are preferably electrically connected to a further busbar on their region protruding from the active layer. The further 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 area and the other areas of the active layer with different surface electrodes, the areas of the active layer can be controlled and switched independently of each other. The first In this configuration, the surface electrode, the electrical bridge and the third surface electrode preferably serve as an anode, with the second surface electrode and the further surface electrode serving as a cathode and being able to have different (cathodical) electrical potentials from one another. 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.

In a preferred embodiment of the invention, the first surface electrode, the second surface electrode and any additional surface electrodes were formed using laser radiation (laser ablation). In other words, an initially unsegmented, continuous surface electrode was divided into a plurality of surface electrodes (at least the first surface electrode and the second surface electrode) using laser radiation. The third surface electrode is preferably not segmented using 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 into a plurality of segments (at least the first and second segments) and a plurality of surface electrodes (at least the first surface electrode and the second surface electrode) using laser radiation. The third surface electrode is not segmented using laser radiation.

In an alternative embodiment, the functional element already has an active layer due to the 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 further surface electrodes that may be present can also be applied separately to the active layer during manufacturing, so that no subsequent introduction of insulation areas is necessary.

If the active layer has further areas or segments, the third surface electrode preferably extends completely over the second surface of the further areas or in the area of the further segments. In particular, the third Surface electrode over the entire second surface of the active layer. This ensures that the functional element can be used to its full extent 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 for the user.

The composite pane is designed, for example, as a windshield or a roof pane that is 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 an external facade of a building or a partition pane inside a building.

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.

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

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

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

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

Plasticizers are chemicals that make plastics softer, more flexible, more pliable and/or more elastic. They shift the thermoelastic range of plastics towards lower temperatures so that the plastics have the desired elastic properties in the range of the application temperature. Other preferred plasticizers are carboxylic acid esters, in particular low-volatility carboxylic acid esters, fats, oils, soft resins and camphor. Other plasticizers are preferably aliphatic diesters of tri- or tetraethylene glycol. Particularly preferred plasticizers are 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 part of the compound. 3G8 stands for triethylene glycol bis(2-ethylhexanoate), i.e. for a compound of the formula C4H9CH (CH2CH3) CO (OCH ₂ CH ₂ )3O ₂ CCH (CH ₂ CH ₃ ) C4H9.

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.

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, the thickness of the thermoplastic intermediate layer after lamination of the layer stack preferably being from 0.25 mm to 1 mm, typically 0.38 mm or 0.76 mm. If the thickness varies over the surface of the composite pane, the values given refer to the thickness at the thickest point of the thermoplastic intermediate layer.

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 the second thermoplastic composite film. The first composite film and the second composite film are preferably arranged flat on top of each other and laminated with each other, with the functional element being inserted between the two composite films. The The areas of the composite films that overlap the functional element form areas 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 composite pane, where the intermediate layers are in direct contact with each other, they can fuse during lamination in such a way that the two original layers may no longer be recognizable and a homogeneous intermediate layer is present instead.

Particularly preferably, the thermoplastic intermediate layer also comprises a third thermoplastic composite film which is arranged all the way around the functional element. In other words, the functional element, or more precisely the side surfaces of the functional element, is surrounded all the way around by the third thermoplastic composite film. The third composite film is designed like a frame 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.

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 alignment. The third composite film preferably has approximately the same thickness as the functional element. This compensates for the local difference in thickness of the composite pane, which is introduced by the locally limited functional element, so that glass breakage during lamination can be avoided.

The side surfaces of the functional element that are visible when looking 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 conspicuous. In the areas where the surface electrodes protrude to the active layer, the side surface of the functional element is the side surface of the active layer, wherein preferably at least one barrier layer is arranged between the side surface of the active layer and the third composite film.

The thickness of each thermoplastic composite film is preferably from 0.1 mm to 2 mm, particularly preferably from 0.2 mm to 1 mm.

In an advantageous development of a composite pane according to the invention, the area of the first and/or the second thermoplastic composite film, via which the functional element is connected to the outer pane or the inner pane, is tinted or colored. In other words, at least the area of the first and/or the second thermoplastic composite film which, when viewed through the composite pane, is congruent with the functional element is tinted or colored. The transmission of this area in the visible spectral range is therefore reduced compared to a non-tinted or colored layer. The tinted/colored area of the composite film thus reduces the transmission of the composite pane in this area. 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 leads to a more neutral appearance that is more pleasant to the viewer.

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 optical appearance.

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 coloring. Such films are available, for example, by coextrusion. Alternatively, an untinted film section and a tinted or colored film section can be assembled to form the thermoplastic intermediate layer.

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 on the inner pane and/or the outer pane. In a preferred embodiment of the invention, at least one section of the peripheral side surface of the active layer is sealed with at least one barrier layer. Preferably, all sections of the peripheral side surface of the active layer are sealed with one or more barrier layers. In addition, areas 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 with the edge areas of the third surface electrode, for example if this is appropriate for production purposes. This results in a particularly secure sealing of the active layer of the functional element and a particularly good resistance to aging of the functional element.

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.

In the context of this invention, “sealed” 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.

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.

In an advantageous embodiment of the invention, the barrier layer is designed such that it prevents the diffusion of plasticizers from the thermoplastic intermediate layer through the barrier layer.

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.

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 called individual layers and can consist of the same material or of different materials.

The individual layer or layers of a multi-layer barrier layer preferably contain a transparent material. In the sense of the invention, a barrier layer is understood to be transparent if it has 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%. For windows or sections of windows that are not in the driver's traffic-relevant field of vision, for example for roof windows or in the upper area of a windshield, or if 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.

In an advantageous embodiment of the invention, the individual layer or 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.

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.

In the context of the present invention, the term "based" in relation 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% by weight, particularly preferably at least 90% by weight and in particular at least 95% by weight. 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" includes the fact that in addition to the metal oxides, metal nitrides or metal oxynitrides, small amounts of residues of the process gases can also be included, such as carbon and hydrogen as organic residues of organometallic compounds.

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 type SiOxCy:H, 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.

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

In an alternative barrier layer, at least one individual layer contains or consists of an organosilicon, the CyHz content of the organosilicon coating being 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.

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

Further preferred individual layers contain other transparent ceramic layers and/or polymer layers that can be produced using 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.

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 on top of one another. 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 other individual layer(s).

In a particularly advantageous embodiment, the barrier layer contains exactly 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.

In an advantageous embodiment, one or more adhesion-improving 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-improving surface treatment. The stacking sequence can be exposed to an argon (Ar) plasma, a nitrogen (N2) plasma or an oxygen (O2) plasma for surface treatment.

In an advantageous embodiment, the entire barrier layer made up of 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 measurement of the thickness of an individual layer or several layers arranged on top of one another as a layer sequence, which are applied to a substrate. It is measured in a 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.

The barrier layers can be produced by any suitable deposition process. Gas phase deposition processes are particularly suitable, as they enable the controlled production of particularly thin barrier layer thicknesses d.

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

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

• Sputtering, such as magnetron sputtering • Atomic layer deposition, such as plasma enhanced atomic layer deposition (PEALD). • Chemical vapor deposition (CVD), particularly preferred plasma enhanced chemical vapor deposition (PECVD) or low pressure chemical vapor deposition (LPCVD) or low temperature low pressure PECVD.

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.

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.

The controllable functional element comprises an active layer between surface electrodes and is designed like a film. The active layer has controllable optical properties, which can be controlled via the voltage applied to the surface electrodes.

The at least first bus conductor and the at least second bus conductor as well as any additional bus conductors present are intended to be electrically connected to an external voltage source in a manner known per se. The electrical contact is made using suitable connecting cables, for example foil conductors.

The surface electrodes, i.e. at least the first, second and third surface electrodes, are preferably designed as transparent, electrically conductive layers. The surface electrodes preferably contain at least one metal, a metal alloy or a transparent conductive oxide (transparent conducting 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 20 nm to 1 pm, very particularly preferably 30 nm to 500 nm. In addition to the active layer and the surface electrodes, the functional element can have other layers known per se, for example barrier layers, blocking layers, anti-reflection layers, protective layers and/or smoothing layers.

The surface electrodes are preferably applied to a carrier film. With such a design of the functional element, the surface electrodes and the active layer are arranged between the carrier films. The carrier films thus form the surfaces of the functional element. The functional element can thus be provided as a laminated film that can be advantageously processed. The functional element is advantageously protected by the carrier films against damage, in particular corrosion. The functional element contains at least

• a first carrier film,

• the first surface electrode and the second surface electrode,

• the active layer,

• the third surface electrode and

• a second carrier film.

The first surface electrode and the second surface electrode, as well as any other surface electrodes, are preferably applied to exactly one continuous carrier foil, i.e. arranged between the carrier foil and the active layer. The carrier foil therefore carries the surface electrodes and provides a liquid or soft active layer with the necessary mechanical stability.

The first surface electrode, the second surface electrode, the third surface electrode and/or optionally further surface electrodes can also be designed 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 are a coating on a carrier foil.

The insulation lines related to insulation lines between surface electrodes, carrier films and/or segments of the active layer have, for example, a width of 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 the person skilled in the art in accordance with the requirements in 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 using laser ablation.

In an alternative embodiment, the first surface electrode is preferably arranged on a first carrier film, the second surface electrode is preferably arranged on a second carrier film and the third surface electrode is preferably arranged on a third carrier film. Any additional surface electrodes present are each arranged on an additional carrier film. The carrier films 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 film and the second carrier film as well as any additional surface electrodes present are preferably separated from one another by an insulation region, particularly preferably by an insulation line.

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. 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.

The functional element is preferably a PDLC functional element (polymer dispersed liquid crystal). The active layer of a PDLC functional element contains liquid crystals which are 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 a 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 possibly other 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 which are transparent when no voltage is applied (zero volts) and scatter strongly when a voltage is applied.

In principle, however, it is also possible to use other types of controllable functional elements, for example electrochromic functional elements or SPD functional elements (suspended particle device). The controllable functional elements mentioned and their functionality are known to the person skilled in the art, so that a detailed description can be omitted at this point. A PDLC functional element is particularly preferred, since effective protection against plasticizers must be guaranteed, especially with PDLC elements, in order not to impair the optical quality of the functional element.

The second region of the active layer can change its optical state by applying a voltage to the first bus bar and the second bus bar. 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 such that they can change their optical state by applying a voltage to the bus bars connected to them.

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.

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 retract, which is visually noticeable and has a negative impact on 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.

The electrical control of the functional element of the composite pane according to the invention installed in a vehicle is carried out, for example, by means of switches, rotary or sliding controls that are integrated in the vehicle's instruments. However, a button for controlling the functional element can also be integrated into the composite pane, for example a capacitive button. Alternatively or additionally, the functional element can be controlled by contactless methods, for example by recognizing gestures, or depending on the state of the pupil or eyelid determined by a camera and suitable evaluation electronics. Alternatively or additionally, the functional element can be controlled by sensors that detect light falling on the pane.

In an advantageous embodiment of the invention, the bus bars are applied by soldering or gluing to the protruding area of the first surface electrode or the second surface electrode and optionally further surface electrodes. The bus bars applied in this way are preferably designed as a wire or strip of an electrically conductive film. The bus bars then contain, for example, at least aluminum, copper, tinned copper, gold, silver, zinc, tungsten and/or tin or alloys thereof. The strip preferably has a thickness of 10 pm to 500 pm, particularly preferably 30 pm to 300 pm. Bus bars made of electrically conductive films with these thicknesses are technically simple to produce and have an advantageous current-carrying capacity. The strip can be electrically connected to the electrically conductive structure, for example, via a solder mass, via an electrically conductive adhesive or by direct application.

Alternatively, the first bus bar and/or the second bus bar and/or the other bus bars that may be present are designed as a printed and burned-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 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 particularly 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.

The specific resistance p _a of the first busbar and/or the second busbar and/or the additional busbars that may be 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 easy to implement and have an advantageous current-carrying capacity.

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, 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.

The first bus conductor and the second bus conductor are preferably arranged in opposite edge regions of the functional element or alternatively arranged at an angle, i.e. arranged offset by essentially 90° to one another. Any additional bus conductors that may be present are preferably arranged like the second bus conductor to the first bus conductor. If the composite pane is used as a vehicle window in a vehicle, the bus conductors are preferably arranged in such a way that they are covered by a covering print of the vehicle window.

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 section of the peripheral side surface of the active layer by means of an adhesive layer. The electrically conductive bridge contains, for example, at least aluminum, copper, tinned copper, gold, silver, Zinc, tungsten and/or tin or alloys thereof. The bridge preferably has a thickness of 5 pm to 400 pm, particularly preferably 40 pm to 250 pm. Electrically conductive bridges with these thicknesses are technically easy to implement and have an 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 mass, via an electrically conductive adhesive or by direct application. The electrically conductive bridge can, for example, be introduced into the functional element after the surface electrodes have been connected to the active layer.

Alternatively, the electrically conductive bridge is designed as a conductive paste. The electrically conductive bridge can be arranged, for example, in an opening in the first region of the active layer, for example a hole-shaped recess in the active layer, so that a direct electrical connection between the first surface electrode and the third surface electrode is made possible. 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 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 very particularly 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.

The specific resistance p _{a of} the electrically conductive bridge is preferably from 0.8 pOhnrcm to 7.0 pOhnrcm and particularly preferably from 1.0 pOhnrcm to 2.5 pOhnrcm. 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 varnish or a polymer film.

The first bus bar is preferably electrically connected to the first surface electrode using an electrically conductive material that contains silver, particularly preferably the material is based on silver. The second bus bar is preferably electrically connected to the second surface electrode using an electrically conductive material, preferably based on silver. It is understood that any additional bus bars that may be present are connected to additional surface electrodes, preferably with an electrically conductive material, preferably based on silver. The electrically conductive material is applied at least, preferably exclusively, between the bus bar and the protruding area of the surface electrode to which the bus bar is connected. This arrangement can be manufactured quickly and easily in terms of production technology, with silver-containing materials being characterized by high electrical conductivity and being relatively stable over the long term.

If something is designed "on the basis of" a material, it consists predominantly of this material, in particular essentially of this material along with any impurities or dopants. The specification of layer thicknesses or thicknesses refers, unless otherwise stated, to the geometric thickness of a layer.

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 edge and the lower edge. The upper edge refers to the edge that is intended to point upwards in the installation position. The lower edge refers to the edge that is intended to point downwards in the installation position. The upper edge is often also referred to as the roof edge and the lower edge as the motor edge.

Windscreens have a central field of vision, the optical quality of which must meet high requirements. The central field of vision must have a high light transmission (according to ISO 9050:2003) (typically greater than 70%). The central field of vision in question is in particular 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 laid down 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 in vehicles"). Field of vision B is defined in Annex 18.

The functional element is then advantageously arranged above the central field of vision (field of vision B). This means that the functional element is arranged 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 completely within this area positioned and does not protrude into the central field of vision. In other words, the functional element is closer to the top edge of the windshield than the central field of vision. Thus, the transmission of the central field of vision is not impaired by the functional element, which is positioned in a similar place to a classic mechanical sun visor when folded down.

The functional element is preferably arranged over the entire width of the composite pane or the windshield, minus an edge 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 composite pane and protected from contact with the surrounding atmosphere and corrosion.

The upper edge and the adjacent side surface or all side surfaces of the functional element are preferably covered by an opaque cover print or an external frame when viewed through the composite pane. Windscreens and vehicle roof windows typically have a peripheral cover print made of an opaque enamel, which serves in particular to protect the adhesive used to install the windscreen from UV radiation and to visually conceal it. This peripheral cover print is preferably used to also cover the upper edge and the 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 composite pane and only the lower edge is potentially visible to the viewer. Preferably, both the outer pane and the inner pane have a cover print so that visibility is prevented from both sides.

The functional element can also have recesses or holes, for example in the area of so-called sensor windows or camera windows of the composite pane, in particular 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 functional elements that are separate from one another, with a distance 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 soda-lime glass, as is usual for window panes. However, the panes can also be made of other types of glass, for example quartz glass, borosilicate glass or aluminosilicate glass, or of rigid clear plastics, for example polycarbonate or polymethyl methacrylate. The panes can be clear, or tinted or colored.

The outer pane, the inner pane and/or the intermediate layer may have other 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).

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

The invention further extends to a glazing unit comprising the composite pane according to the invention. The first busbar and the second busbar and 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 on the busbars. If present, different optical states can also be controlled in other regions of the active layer by means of electrical voltage changes on the busbars. The voltage changes on 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 implemented by suitable connecting cables, for example foil conductors.

The invention also extends to a method for producing a composite pane. The method comprises the following method steps in the order given: a) In a first method 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 process 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.

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.

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.

The electrical contact of the busbars is preferably made before the laminated pane is laminated.

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.

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

The invention further comprises 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 sun protection, sun visor or as privacy protection, preferably as a sun visor. The invention further comprises the use of the composite pane according to the invention as a windshield or roof pane of a vehicle.

The invention further includes 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 with a first surface, a second surface and a circumferential side surface, a first surface electrode which extends over the first surface in a first region of the active layer and a second surface electrode which extends over the first surface in a second region of the active layer. In addition, the functional element comprises a third surface electrode which extends over the second surface at least in the first and second regions of the active layer and an electrical bridge which electrically connects the first surface electrode to the third surface electrode. The first surface electrode also has a region which protrudes first from the active layer and the second surface electrode has a region which protrudes second from the active layer. In addition, a first busbar is arranged at least on the first protruding region and a second busbar is arranged at least on the second protruding region. The first surface electrode and the second surface electrode are electrically insulated from one another.

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

Figure 1 shows an embodiment of the functional element with busbars 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,

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,

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,

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,

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 of Figures 6 and 7.

Figures 1, 2 and 3 each show a detail of a functional element 4 with electrically controllable optical properties, such as could be part 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 which shows 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.

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 connects the first surface electrode 6.1 to the third surface electrode 6.3 in an electrically conductive manner.

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 shown 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 each other. In the case of the segmented active In 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 by laser ablation, for example. The insulation lines have a width of 50 pm, for example.

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), so that the first surface electrode 6.1 has a projecting area U' 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), so that the second surface electrode 6.2 has a projecting area II" to the active layer 5. The projection u of the first surface electrode 6.1 to the active layer 5 and the projection u of the second surface electrode 6.2 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).

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 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. The electrically conductive bridge 7 can alternatively 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).

The first bus conductor 8.1 and the second bus conductor 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.

The surface electrodes 6.1, 6.2, 6.3 are each applied to a carrier film (carrier film is 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.

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, whereby the optical properties can 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, at which liquid crystals in the second segment 5.2 realign themselves.

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 as essentially 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 cut 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, with the section line XX' indicated in Figure 4.

The composite pane 100 comprises an outer pane 1 and an inner pane 2, which are connected to one another via a thermoplastic intermediate layer 3. The outer pane 1 has a thickness of 2.1 mm and is made, for example, of a clear soda-lime glass. The inner pane 2 has a thickness of 1.6 mm and is also made, for example, of a 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.

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

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 in a flat stacked manner 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% by weight of polyvinyl butyral (PVB) and 22% by weight of 2,2'-ethylenedioxydiethylbis(2-ethylhexanoate) as a plasticizer.

The functional element 4 is arranged between the first thermoplastic composite film 3.1 and the second thermoplastic composite film 3.2, and its optical properties can be controlled by an electrical voltage. The electrical supply lines are not shown for the sake of simplicity. The first thermoplastic composite film 3.1 is connected to the outer pane 1, the second thermoplastic composite film 3.2 is connected to the inner pane 2. The third thermoplastic composite film 3.3 in between has a cutout into which the cut functional element 4 fits precisely. that is to say, it is inserted 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 encapsulated all around in thermoplastic material and is thus protected.

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.

The first composite film 3.1 can have a tinted area that is arranged between the functional element 4 and the outer pane 1 (not shown here). The light transmission of the windshield is thereby further reduced in the area of the functional element 4 (for example, light transmission of 30% in the tinted area) and the milky appearance of the PDLC functional element 4 in the diffuse state is reduced. The aesthetics of the windshield are thus made significantly more appealing.

The composite pane 100 has, as is usual for windshields, a peripheral covering 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. 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 covering print 11, so that the side surfaces of the functional element 4 - with the exception of the side edge pointing towards the central field of view B - are covered by the covering print 11. The electrical connections (not shown) including the busbars 8.1, 8.2 are also sensibly attached in the area of the covering print 11 and thus hidden.

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 (ie 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 (ie the surface facing the second thermoplastic composite film 3.2) with a barrier layer 9, which does not have a protruding area U', U" through the first or second surface electrode 6.1, 6.2 (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 Figures 1 to 3). The term "circumferential side surface of the functional element 4" essentially means the circumferential side surface S of the active layer 5, as shown in Figures 1 to 3.

The barrier layers 9 reduce or prevent diffusion of plasticizer into the active layer 5, which increases the service life 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.

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 X-X' 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 the form of a frame 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.

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 areas 5.2, 5'; for more details, see 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, minus a peripheral edge area 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 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 Figure 8). The functional element 4 has no barrier layer 9 on the 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 other surface electrodes 6' have a protruding region U', U", U"' to the active layer 5, whereby a protrusion along the entire circumferential edge of the active layer 5 is achieved 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 means the circumferential side surface S of the active layer 5, as shown in Figure 8.

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, 3.3 each have a thickness of 0.38 mm, for example, and consist of 78% by weight of polyvinyl butyral (PVB) and 22% by weight of 2,2'-ethylenedioxydiethylbis(2-ethylhexanoate) as a plasticizer.

Figure 8 shows the functional element 4 in a side view, which in the embodiment of Figures 6 and 7 is part 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 are discussed here and otherwise reference is made to the description of Figures 1 to 3.

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 surface electrodes 6.1, 6.2, 6' that are electrically insulated from one another are applied to the first surface A of the active layer 5. The second surface electrode 6.2 and the other 3 surface electrodes 6' are arranged in strips next to one another on the active layer 5, so that in plan view 4 essentially rectangular-shaped areas can be seen (see Figure 6). The Surface electrodes 6.2, 6' are arranged parallel to each other and next to each other, with the longer sides of the individual surface electrodes 6', 6.2 facing each other. The surface electrodes 6.1, 6.2, 6' are separated from each other by insulation lines, for example introduced by laser ablation. The insulation lines have a width of 50 pm, for example.

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. areas separated from one another by an insulation area. The entire active layer 5 is a continuous layer, which, however, can nevertheless be divided into a first area 5.1, a second area 5.2 and three further areas 5' due to the divided surface electrodes 6.1, 6.2, 6' on the first surface A. In the second area 5.2 and the further areas 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 area 5.2 and the further areas 5' can be switched independently of one another, whereby the active layer 5 can be in different optical states depending on the area 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.

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 an area LT, II", U"' projecting towards the active layer 5 (only shown 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 along the entire circumferential side surface S towards the active layer 5, 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:

1 outer pane

2 inner panes

3 thermoplastic intermediate layer

3.1 first thermoplastic composite film of the intermediate layer 3

3.2 second thermoplastic composite film of the intermediate layer 3

3.3 third thermoplastic composite film of the intermediate layer 3

4 functional element

5 active layer

5.1 first segment/first area of the active layer 5

5.2 second segment/second area of the active layer 5

5‘ further segments/further areas of the active layer 5

6.1 first surface electrode

6.2 second surface electrode

6.3 third surface electrode

6' additional surface electrodes

7 electric bridge

8.1 first collector

8.2 second collector

8' additional collectors

9 barrier layer

10 voltage source

11 cover print

100 composite panes

I outside surface of the outer pane 1

II interior surface of the outer pane 1

III outer surface of the inner pane 2

IV interior surface of the inner pane 2

A first surface of the active layer 5

B second surface of the active layer 5

S circumferential side surface of the active layer 5

S‘ first section of the side surface S

S" second section of the side surface S

U' protruding area of the first surface electrode 6.1 II“ protruding area of the second surface electrode 6.2

U“‘ protruding area of another surface electrode 6‘

X-X‘ section line H central field of view of the composite pane 100 as windshield

D Upper edge of the composite pane 100, roof edge

M Lower edge of the composite pane 100, motor edge

Claims

patent claims 1. 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 over the second surface (B) at least in the first and second regions (5.1, 5.2) of the active layer (5), and an electrical bridge (7) which connects the first surface electrode (6.1) to the third surface electrode (6.2). Surface electrode (6.3) is electrically connected, wherein the first surface electrode (6.1) has a first projecting region (U') to the active layer (5) and the second surface electrode (6.2) has a second projecting region (LT) to 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 protruding region (U') and the second protruding region (LT) together protrude 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 silver-containing material. 11. Glazing unit comprising a composite pane (100) according to one of claims 1 to 10, wherein the first and the second busbar (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 one of claims 1 to 10, wherein a) the first busbar (8.1) is connected to the first surface electrode (6.1) of the functional element (4) and the second busbar (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.