FUNCTIONAL ELEMENT WITH ELECTRICALLY CONTROLLED OPTICAL PROPERTIES

Description

[0001] The invention relates to a composite disc with a functional element having electrically controllable optical properties, a method for its manufacture, and its use.

[0002] In the automotive and construction sectors, laminated glass with electrically controlled functional elements for sun protection or privacy is often used.

[0003] For example, windshields are known to incorporate a sun visor 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 spectrum can be electrically controlled. The functional elements are usually film-like and are laminated into or bonded to a laminated windshield. With these windshields, the driver can control the transmission behavior of the windshield to sunlight. This eliminates the need for a conventional mechanical sun visor. As a result, the vehicle's weight can be reduced, and space is gained in the roof area. Furthermore, electrically controlling the sun visor is more convenient for the driver than manually lowering a mechanical one.

[0004] Windscreens with such electrically controlled sun visors are known, for example, from WO 2014 / 086555 A1, WO 2017 / 157626 A1, DE 102013001334 A1, DE 102005049081 B3, DE 102005007427 A1 and DE 102007027296 A1.

[0005] Typical electrically controllable functional elements contain electrochromic layer structures or suspended particle device (SPD) films, as known, for example, from US 2005 / 227061 A1. Other possible functional elements for realizing electrically controllable sun protection are so-called PDLC functional elements ( polymer dispersed liquid crystal ), as is known, for example, from DE 20 2018 102520 U1. Its active layer contains liquid crystals embedded in a polymer matrix. When no voltage is applied, the liquid crystals are randomly oriented, resulting in strong scattering of the light passing through the active layer. When 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 and more by increasing scattering to ensure glare control.

[0006] Conventional, laminated functional elements, and especially PDLC functional elements, often show undesirable signs of aging in the edge area, such as lightening and changes in shading, as is known, for example, from WO 2010 / 032068 A1.

[0007] DE 202018102520 U1 shows a functional element with a carrier film with an overhang, on which a busbar is arranged.

[0008] WO 2017 / 157626 A1 shows a functional element with an edge seal which rests against the two outer surfaces of the carrier films.

[0009] US 2014063432 A1 discloses a display device comprising a first glass substrate, a first electrically conductive layer, a liquid crystal layer, a second electrically conductive layer, and a second glass substrate. The second glass substrate has an overhang, wherein a first sealant and a second sealant are applied such that they are in contact with a peripheral region of the outer surface of the first glass substrate and the inner surface of the second glass substrate, sealing the liquid crystal layer.

[0010] The present invention is therefore based on the objective of providing a composite disc with an improved functional element with electrically controllable optical properties, which is improved in particular with regard to its aging resistance.

[0011] The object of the present invention is achieved by a composite disk with a functional element having electrically controllable optical properties according to independent claim 1. Preferred embodiments are described in the dependent claims.

[0012] Further aspects of the invention include a method for manufacturing and using the composite disc according to the invention with a functional element having optically controllable properties.

[0013] The functional element with electrically controllable optical properties of the composite disc according to the invention comprises at least one stacking sequence of a first carrier film, a first surface electrode, an active layer, a second surface electrode and a second carrier film, wherein the second carrier film has a protruding area over the first carrier film and a barrier film is arranged on at least one edge area of ​​the first carrier film and the protruding area of ​​the second carrier film.

[0014] In the functional element, the barrier film spans the area between the protruding portion of the second carrier film and the edge of the first carrier film where the exit surface of the active layer is located. The barrier film thus seals the exit surface of the active layer between the first and second carrier films at their respective edges.

[0015] The first surface electrode is arranged on the inner surface of the first carrier film and preferably directly connected to it. The second surface electrode is arranged on the inner surface of the second carrier film and preferably directly connected to it. Only the second surface electrode can be positioned between the second carrier film and the barrier film. Alternatively, the second surface electrode can be omitted in this area, which improves the adhesion and bond between the barrier film and the second carrier electrode.

[0016] The barrier film is thus positioned in the protruding area on the inner surface of the second carrier film and at the edge of the outer surface of the first carrier film. The barrier film covers and seals the exit surface of the active layer located between the first and second carrier films at the respective side edge. This allows for a compact and low-profile design that is particularly well-suited for lamination into a laminated glass unit. Advantageously, the barrier film does not wrap around the second carrier film and does not touch its outer surface.

[0017] In the functional element, the second carrier film has an overhang beyond the first carrier film; that is, the second carrier film has a protruding area with width u. In other words, the second carrier film is wider in this area.

[0018] The terms "overhang" and "protrude" mean, as is commonly used, to extend beyond something in a lateral (horizontal) direction. In this case, the second support film extends beyond the first support film in the plane of the functional element. "Lateral" here means, as is commonly used, to the side or to the side.

[0019] The protruding area advantageously has a width u of at least 3 mm, preferably of at least 5 mm and particularly preferably of at least 8 mm.

[0020] The protruding area advantageously has a maximum width u of 50 mm, preferably of 20 mm and particularly preferably of 10 mm.

[0021] In the functional element, at least one side edge, preferably three side edges, and particularly preferably all side edges, has a projecting area of ​​the second carrier film beyond the first carrier film, each of which is covered with one, three, or more barrier films. The stacking sequence is reversed in the area of ​​contact with the surface electrode. This area can also be extended to a complete side edge or several side edges.

[0022] Advantageously, the barrier film is bonded to the outer surface of the first carrier film in a material-bonded and / or form-locking manner, preferably fused and / or glued.

[0023] Furthermore, the barrier film is advantageously bonded to the inner surface of the second carrier film by a material-bonded and / or form-fit connection, preferably fused and / or glued. It is particularly advantageous if the barrier film is only connected to the inner surface of the second carrier film at specific points, preferably by fusion and / or glue.

[0024] The barrier film is fully or partially bonded to the first and second carrier films.

[0025] In an advantageous embodiment of the functional element, the width w of the edge region of the barrier film on the first carrier film is at least 3 mm, preferably at least 4 mm, particularly preferably at least 5 mm and in particular at least 8 mm.

[0026] In a further advantageous embodiment of the functional element, the width w of the edge region of the barrier film on the first carrier film is less than 50 mm, preferably less than 30 mm and particularly preferably less than 10 mm.

[0027] The composite disc according to the invention comprises a stacking sequence of an outer disc, a first intermediate layer, a second intermediate layer and an inner disc, wherein the intermediate layers each contain at least one thermoplastic polymeric film with at least one plasticizer, wherein a functional element with electrically controllable optical properties is arranged at least sectionally between the first intermediate layer and the second intermediate layer.

[0028] The laminated glass can be, for example, the windshield or roof window of a vehicle, or other vehicle glazing, such as a partition in a vehicle, preferably a rail vehicle or bus. Alternatively, the laminated glass can be architectural glazing, for example in the exterior facade of a building, or a partition inside a building.

[0029] 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.

[0030] If the laminated glass is intended to separate an interior space from the outside environment in a window opening of a vehicle or building, then, for the purposes of this invention, the inner pane (second pane) is defined as the pane facing the interior (vehicle interior). The outer pane (first pane) is defined as the pane facing the outside environment. However, the invention is not limited to this.

[0031] Similarly, the functional element in the laminated glass can be arranged on both sides. That is, either the first carrier film is arranged on the side of the functional element facing the outer pane or on the side of the functional element facing the inner pane.

[0032] The composite disc according to the invention contains a functional element with electrically controllable optical properties, which is arranged at least section by section between a first intermediate layer and a second intermediate layer. The first and second intermediate layers typically have the same dimensions as the outer and inner discs. The functional element is preferably film-like.

[0033] As mentioned above, in the functional element, the barrier film and the first and second carrier films are locally bonded together at points, in sections, or across the entire surface, for example, by fusing or gluing. This creates a sufficient and reliable diffusion barrier for plasticizers from the intermediate layer and reduces or prevents clouding of the edge area of ​​the functional element.

[0034] In an advantageous embodiment of the composite disc according to the invention, the barrier film(s) is preferably pressed onto the first and second carrier films (for example, by lamination within the composite disc). Bonding, fusing, or welding (for example, by local heating) is then optional. This creates a sufficient and reliable diffusion barrier for plasticizers from the intermediate layer and reduces or prevents clouding of the edge region of the functional element.

[0035] In a further advantageous embodiment of the functional element, the barrier films are fully bonded to the adjacent surfaces of the first and second carrier films, preferably by adhesive, for example, by an adhesive, in particular by an acrylic-based adhesive, preferably acrylate-based, and most preferably by an adhesive containing more than 50% methyl methacrylate. This has the particular advantage that slippage of the barrier film during assembly and lamination is prevented, and the barrier film is firmly and tightly bonded to the functional element. This, among other things, prevents air inclusions between the barrier film and the functional element, and the optical quality of such laminated glass is particularly high.

[0036] Alternatively, the barrier film can be fixed with an acrylic-based liquid. During lamination, the liquid is drawn out of the contact surface between the barrier film and the carrier film by a vacuum or diffuses into the films.

[0037] In a further advantageous embodiment of the composite disc according to the invention, the barrier films are only partially connected to the first and / or the second carrier film, so that during venting during the lamination process, trapped air between the barrier film and the functional element can escape and no air inclusions remain that would reduce the optical quality of the composite disc.

[0038] The invention is based on the inventors' finding that the diffusion of plasticizers from the intermediate layers into the interior of the functional element leads to a lightening or alteration of transmission during aging, which impairs the transparency and aesthetics of the laminated glass. By sealing the functional element with a barrier film that inhibits or prevents the diffusion of plasticizers from the intermediate layer into the functional element, and in particular into the side edge of the functional element, such aging effects are significantly reduced or completely prevented. The material of the carrier films and the barrier layer is selected such that the diffusion of plasticizers is prevented or reduced.

[0039] The sealing in the area of ​​the exit surface of the active layer, i.e. the surface through which plasticizers can penetrate into the active layer, is achieved by means of the barrier film which is adjacent to the protruding area of ​​the second carrier film and / or the first carrier film, pressed (for example by lamination inside the composite disc), glued (for example with an adhesive) or welded (for example by local heating).

[0040] In an advantageous embodiment of the composite disc according to the invention, the intermediate layer contains a polymer, preferably a thermoplastic polymer.

[0041] In a particularly advantageous embodiment of the composite disc according to the invention, the intermediate layer contains at least 3 wt.%, preferably at least 5 wt.%, particularly preferably at least 20 wt.%, even more preferably at least 30 wt.%, and particularly at least 40 wt.% of a plasticizer. The plasticizer contains or preferably consists of triethylene glycol bis(2-ethylhexanoate).

[0042] Plasticizers are chemicals that make plastics softer, more flexible, more pliable, and / or more elastic. They shift the thermoelastic range of plastics to lower temperatures, so that the plastics exhibit the desired more elastic properties within the operating temperature range. Other preferred plasticizers include carboxylic acid esters, especially low-volatility carboxylic acid esters, fats, oils, soft resins, and camphor. Aliphatic diesters of triethylene glycol or tetraethylene glycol are also preferred. 3G7, 3G8, or 4G7 are particularly preferred as plasticizers, where the first digit denotes the number of ethylene glycol units and the last digit the number of carbon atoms in the carboxylic acid moiety of the compound. Thus, 3G8 stands for triethylene glycol bis-(2-ethylhexanoate), i.e., a compound of the formula C 4 H 9 CH (CH 2 CH 3 ) CO (OCH 2 CH 2 ) 3 O 2 CCH (CH 2 CH 3 ) C 4 H 9 .

[0043] In a further particularly advantageous embodiment of the composite disc according to the invention, the intermediate layer contains at least 60 wt.%, preferably at least 70 wt.%, particularly preferably at least 90 wt.% and in particular at least 97 wt.% polyvinyl butyral.

[0044] The thickness of each intermediate layer is preferably from 0.2 mm to 2 mm, more preferably from 0.3 mm to 1 mm, particularly from 0.3 mm to 0.5 mm, for example 0.38 mm.

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

[0046] In a particularly advantageous embodiment of the functional element, the barrier film is low in plasticizers, preferably with a plasticizer content of less than 3 wt.%, more preferably less than 1 wt.%, and particularly less than 0.5 wt.%. Most preferably, the barrier film is plasticizer-free, i.e., without the targeted addition of a plasticizer. The barrier film contains or consists of a polymer, preferably polyethylene terephthalate (PET) or polyvinyl fluoride (PVF). The barrier film can also contain low-plasticizer polyvinyl butyral (PVB) with a plasticizer content of less than 3 wt.%.

[0047] The optically controllable functional element comprises an active layer between two surface electrodes. The active layer exhibits controllable optical properties, which can be controlled by the voltage applied to the surface electrodes. The surface electrodes and the active layer are typically arranged essentially parallel to the surfaces of the functional element and, in a composite disk, essentially parallel to the surfaces of the outer and inner disks. The surface electrodes are electrically connected to an external voltage source in a known manner. This electrical contact is achieved using suitable connecting cables, such as foil conductors, which are optionally connected to the surface electrodes via bus bars, for example, strips of an electrically conductive material or electrically conductive imprints.

[0048] The 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 conducting oxide (TCO). The surface electrodes can, for example, contain 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 µm, particularly preferably 20 nm to 1 µm, and most preferably 30 nm to 500 nm.

[0049] In addition to the active layer and the surface electrodes, the functional element may have other layers known per se, for example barrier layers, blocker layers, antireflection layers, IR reflection layers, protective layers and / or smoothing layers.

[0050] The functional element is a multilayer film with two outer carrier films. In such a multilayer film, the surface electrodes and the active layer are arranged between the two carrier films. The term "outer carrier film" here refers to the fact that the carrier films form the two surfaces of the multilayer film. This allows the functional element to be provided as a laminated film that can be advantageously processed. The carrier films advantageously protect the functional element from damage, particularly corrosion. The multilayer film contains, in the specified order, at least a first carrier film, a first surface electrode, an active layer, a second surface electrode, and a second carrier film. The carrier film, in particular, supports the surface electrodes and provides the necessary mechanical stability to a liquid or soft active layer.

[0051] The carrier films preferably contain at least one thermoplastic polymer, particularly preferably low-plasticizer or plasticizer-free polyethylene terephthalate (PET). This is especially advantageous with regard to the stability of the multilayer film. However, the carrier films can also contain or consist of other low-plasticizer or plasticizer-free polymers, for example, ethylene vinyl acetate (EVA), polypropylene, polycarbonate, polymethyl methacrylate, polyacrylate, polyvinyl chloride, polyacetate resin, casting resins, acrylates, fluorinated ethylene propylenes, polyvinyl fluoride, and / or ethylene tetrafluoroethylene. The thickness of each carrier film is preferably from 0.04 mm to 1 mm, particularly preferably from 0.04 mm to 0.2 mm.

[0052] The carrier films each have an electrically conductive coating that faces the active layer and acts as a surface electrode.

[0053] In a further advantageous embodiment of the composite disc according to the invention, the functional element is a PDLC functional element ( polymer dispersed liquid crystal The active layer of a PDLC functional element contains liquid crystals embedded in a polymer matrix. When no voltage is applied to the surface electrodes, the liquid crystals are randomly oriented, resulting in strong scattering of the light passing through the active layer. The composite disk thus becomes an almost homogeneous light source. When 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 increases. Objects behind the disk become visible.

[0054] However, it is also possible in principle to use other types of controllable functional elements, for example electrochromic functional elements or SPD functional elements ( suspended particle device The aforementioned controllable functional elements and their operation are known to the person skilled in the art, so a detailed description can be omitted here.

[0055] Functional elements as multilayer films are commercially available. The functional element to be integrated is typically cut from a larger multilayer film into 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 edge is more stable in this case than with mechanical cutting. With mechanically cut edges, there is a risk of damaging the layer structure and the functional element no longer switching as intended, which is visually noticeable and negatively affects the aesthetics of the disc.

[0056] In the composite disc according to the invention, the functional element is connected to the outer disc via a region of the first intermediate layer and to the inner disc via a region of the second intermediate layer. The intermediate layers are preferably arranged flat against each other and laminated together, with the functional element being inserted between the two layers. The regions of the intermediate layers that overlap with the functional element then form the areas that connect the functional element to the discs. In other regions of the disc, where the intermediate layers are in direct contact with each other, they can fuse during lamination to such an extent that the two original layers may no longer be recognizable, and instead a homogeneous intermediate layer is present.

[0057] An intermediate layer can be formed, for example, by a single thermoplastic film. An intermediate layer can also be formed as a stack of two, three, or more layers of film, with the individual films having the same or different properties. An intermediate layer can also be formed from sections of different thermoplastic films whose edges are adjacent to each other.

[0058] In an advantageous embodiment of the composite glass according to the invention, the area of ​​the first or second intermediate layer, through which the functional element is connected to the outer or inner pane, respectively, is tinted or colored. The transmission of this area in the visible spectral range is therefore reduced compared to an untinted or uncolored layer. The tinted / colored area of ​​the intermediate layer thus reduces the transmission of the windshield in the area of ​​the sun visor. In particular, the aesthetic appearance of the functional element is improved because the tinting results in a more neutral appearance that is more pleasing to the observer.

[0059] To enhance functionality, an intermediate layer for acoustically optimized panes can also consist of three individual layers. In such cases, the intermediate layer is 0.05 mm to 0.2 mm thicker.

[0060] Another alternative is thermal improvement through an IR-reflective coated PET film. In this case, the outward-facing intermediate layer also consists of at least three layers (PVB-PET-PVB). The IR-reflective functional layer can be oriented inwards or outwards.

[0061] Electrically controllable optical properties, as defined in the invention, are those properties that can be continuously controlled, but also those that can be switched between two or more discrete states.

[0062] The electric control of the sun visor is achieved, for example, via switches, rotary knobs, or sliders integrated into the vehicle's dashboard. Alternatively, a button for controlling the sun visor can be integrated into the laminated glass, such as the windshield, for example, a capacitive button. The sun visor can also be controlled by contactless methods, such as gesture recognition, or based on the state of the pupil or eyelid as determined by a camera and suitable evaluation electronics. Finally, the sun visor can be controlled by sensors that detect light falling on the glass.

[0063] The tinted or colored area of ​​the intermediate layer preferably exhibits a transmission in the visible spectral range of 1% to 50% in its transparent state, particularly preferably 10% to 40%. This results in particularly good results with regard to glare control and optical appearance.

[0064] The intermediate layer can be formed by a single thermoplastic film in which the tinted or colored area is created by local tinting or dyeing. Such films are available, for example, through co-extrusion. Alternatively, an untinted film section and a tinted or colored film section can be combined to form the thermoplastic layer.

[0065] The tinted or colored area can be homogeneously colored or tinted, meaning it exhibits a location-independent transmission. However, the tint or coloring can also be inhomogeneous, in particular, a transmission gradient can be implemented. In one embodiment, the transmission coefficient in the tinted or colored area increases, at least section by section, with increasing distance from the upper edge. This avoids sharp edges in the tinted or colored area, resulting in a gradual transition from the sun visor to the transparent area of ​​the windshield, which is more aesthetically pleasing.

[0066] In an advantageous embodiment, the area of ​​the first intermediate layer, i.e., the area between the functional element and the outer pane, is tinted. This creates a particularly aesthetically pleasing appearance when viewed from above. The area of ​​the second intermediate layer, between the functional element and the inner pane, can optionally be additionally colored or tinted.

[0067] The composite glass with electrically controllable functional element is advantageously designed as a windshield with electrically controllable sun visor.

[0068] Such a windshield has a top edge and a bottom edge, as well as two side edges running between the top and bottom edges. The top edge is the edge that is intended to point upwards when installed. The bottom edge is the edge that is intended to point downwards when installed. The top edge is often also referred to as the roof edge and the bottom edge as the engine edge.

[0069] Windshields have a central viewing area with stringent optical quality requirements. This central viewing area must have high light transmission (typically greater than 70%). This central viewing area is specifically the area referred to by those skilled in the art as viewing area B, viewing zone B, or viewing zone B. Viewing area B and its technical requirements are defined in Regulation No. 43 of the United Nations Economic Commission for Europe (UN / ECE) (ECE-R43, "Uniform provisions for the approval of safety glazing materials and their installation in vehicles"). Viewing area B is defined in Annex 18 of this regulation.

[0070] The functional element is advantageously positioned above the central field of vision (field of vision B). This means that the functional element is located in the area between the central field of vision and the upper edge of the windshield. The functional element does not need to cover the entire area, but it is positioned completely within this area and does not protrude into the central field of vision. In other words, the functional element is closer to the upper edge of the windshield than the central field of vision. Thus, the transmission of light through the central field of vision is not impaired by the functional element, which is positioned in a similar location to a conventional mechanical sun visor when folded down.

[0071] The windshield is preferably intended for a motor vehicle, especially preferably for a passenger car.

[0072] In a preferred embodiment, the functional element, more precisely its side edges, is surrounded by a third intermediate layer. This third intermediate layer is frame-like with a recess into which the functional element is inserted. The third intermediate layer can also be formed by a thermoplastic film into which the recess has been cut. Alternatively, the third intermediate layer can be composed of several film sections surrounding the functional element. Preferably, the intermediate layer consists of at least three thermoplastic layers arranged on top of each other, with the middle layer having a recess in which the functional element is located.During manufacturing, the third intermediate layer is positioned between the first and second intermediate layers, with the side edges of all intermediate layers preferably aligned. The third intermediate layer preferably has approximately the same thickness as the functional element. This compensates for the local thickness variation in the windshield introduced by the localized functional element, thus preventing glass breakage during lamination.

[0073] The side edges of the functional element, visible through the windshield, are preferably flush with the third intermediate layer, so that there is no gap between the side edge of the functional element and the corresponding side edge of the intermediate layer. This applies particularly to the lower edge of the functional element, which is typically visible. This makes the boundary between the third intermediate layer and the functional element less visually noticeable.

[0074] In a preferred embodiment, the lower edges of the functional element and the tinted area of ​​the intermediate layer(s) are adapted to the shape of the upper edge of the windshield, resulting in a more visually appealing appearance. Since the upper edge of a windshield is typically curved, particularly concave, the lower edge of the functional element and the tinted area is also preferably curved. Most preferably, the lower edges of the functional element are formed essentially parallel to the upper edge of the windshield. However, it is also possible to construct the sun visor from two straight halves arranged at an angle to each other and approximating the shape of the upper edge in a V-shape.

[0075] In one embodiment of the invention, the functional element is divided into segments by insulating lines. The insulating lines can, in particular, be incorporated into the surface electrodes, so that the segments of the surface electrode are electrically isolated from one another. The individual segments are connected to the voltage source independently of each other, so that they can be controlled separately. This allows different areas of the sun visor to be switched independently. Preferably, the insulating lines and the segments are arranged horizontally in the installed position. This allows the user to control the height of the sun visor. The term "horizontal" is to be interpreted broadly here and refers to a direction of propagation that, in the case of a windshield, runs between the side edges of the windshield.The insulation lines do not necessarily have to be straight, but can also be slightly curved, preferably adapted to any curvature of the upper edge of the windshield, and in particular essentially parallel to the upper edge of the windshield. Vertical insulation lines are of course also conceivable.

[0076] The insulation lines have a width of, for example, 5 µm to 500 µm, in particular 20 µm to 200 µm. The width of the segments, i.e., the distance between adjacent insulation lines, can be selected by a person skilled in the art according to the requirements of the individual case.

[0077] The isolation lines can be introduced during the manufacturing of the functional element by laser ablation, mechanical cutting, or etching. Already laminated multilayer films can also be segmented subsequently using laser ablation.

[0078] The top edge and side edges, or all side edges, of the functional element are preferably concealed by an opaque cover print or an outer frame when viewed through the laminated glass. Windshields typically feature a circumferential cover print made of an opaque enamel, which serves in particular to protect the adhesive used to install the windshield from UV radiation and to visually conceal it. This peripheral cover print is preferably also used to conceal the top edge and side edges of the functional element, as well as the necessary electrical connections. The sun visor is then advantageously integrated into the appearance of the windshield, and only the lower edge is potentially visible to the observer. Preferably, both the outer and inner panes have a cover print, so that visibility from both sides is obstructed.

[0079] The functional element can also have cutouts or holes, for example in the area of ​​so-called sensor windows or camera windows. 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, such as rain sensors. It is also possible to implement the sun visor with at least two separate functional elements, with a gap between the functional elements that provides space for sensor or camera windows.

[0080] The functional element (or the entirety of functional elements in the case of several functional elements described above) is preferably arranged across the entire width of the laminated glass or windshield, minus a border area on both sides with a width of, for example, 2 mm to 50 mm. The functional element also preferably has a distance of, for example, 2 mm to 200 mm from the top edge. The functional element is thus encapsulated within the interlayer and protected from contact with the surrounding atmosphere and from corrosion.

[0081] The outer and inner panes are preferably made of glass, particularly preferably soda-lime glass, as is common for window panes. However, the panes can also be made of other types of glass, such as quartz glass, borosilicate glass, or aluminosilicate glass, or of rigid, clear plastics, such as polycarbonate or polymethyl methacrylate. The panes can be clear, tinted, or colored. Windshields must have sufficient light transmission in the central field of vision, preferably at least 70% in the main viewing area A according to ECE-R43.

[0082] The outer pane, the inner pane and / or the intermediate layer may have further suitable coatings known per se, for example anti-reflective coatings, non-stick coatings, anti-scratch coatings, photocatalytic coatings or sun protection coatings or low-emissive coatings).

[0083] The thickness of the outer and inner panes can vary widely and thus be adapted to the requirements of individual cases. The outer and inner panes preferably have thicknesses of 0.5 mm to 5 mm, and particularly preferably of 1 mm to 3 mm.

[0084] The invention also includes a method for manufacturing the composite disc according to the invention, wherein at least a) an outer disc, a first intermediate layer, a functional element according to the invention with electrically controllable optical properties, a second intermediate layer and an inner disc are arranged one above the other in this order, b) the outer disc and the inner disc are joined by lamination, wherein an intermediate layer with an embedded functional element is formed from the first intermediate layer and the second intermediate layer.

[0085] The electrical contacting of the surface electrodes of the functional element preferably takes place before laminating the composite disc.

[0086] Any existing prints, such as opaque cover prints or printed conductors for electrical contacting the functional element, are preferably applied using screen printing.

[0087] Lamination is preferably carried out under the influence of heat, vacuum and / or pressure. Known lamination processes can be used, for example, autoclave processes, vacuum bag processes, vacuum ring processes, calender processes, vacuum laminators or combinations thereof.

[0088] In the manufacture of the functional element with electrically controllable optical properties, at least the following is done: a) a stacking sequence consisting of a first carrier film, a first surface electrode, an active layer, a second surface electrode and a second carrier film, b) the first carrier film is cut back at least one side edge, preferably all side edges, by a region of width u, thereby forming a protruding region of the second carrier film, and c) a barrier film is arranged on the protruding region and adjacent to the side edge, an exit surface of the active layer and an adjacent edge region of the first carrier film.

[0089] The arrangement of the barrier layer ensures that the exit surface is securely and permanently sealed.

[0090] In an advantageous embodiment of the method, in process step c), the barrier film and the first and / or second carrier film are bonded together section by section or completely, for example with an acrylic or acrylate adhesive. Such fixed barrier films can be processed more easily and precisely, especially in automated processes.

[0091] In an advantageous embodiment of the method, an electrical contact such as a busbar is arranged on the protruding area of ​​the second carrier film. The electrical contact can be connected to the surface electrode on the second carrier film.

[0092] In an advantageous embodiment of the method, at least in a region of a further side edge, the second carrier film is cut back, thereby forming a protruding area of ​​the first carrier film, and a further barrier film is arranged on the protruding area, the exit surface of the active layer, and an adjacent edge region of the second carrier film. Advantageously, a further electrical contact, such as a busbar, can be arranged in this area. The electrical contact can be connected to the surface electrode on the first carrier film.

[0093] The invention further comprises the use of the laminated glass according to the invention with an electrically controllable functional element as interior or exterior glazing in a vehicle or building, wherein the electrically controllable functional element is used as sun protection, thermal protection, or privacy protection. The invention also shows the use of the laminated glass according to the invention as a windshield or roof window of a vehicle, wherein the electrically controllable functional element is used as a sun visor. Here, too, segmentation can be advantageous so that, in the absence of a roller blind or visor, the incidence of sunlight can be individually adjusted locally.

[0094] A major advantage of the invention, when using laminated glass as a windshield, is that a conventional, mechanically folding sun visor mounted on the vehicle roof can be dispensed with. The invention therefore also encompasses a vehicle, preferably a motor vehicle, in particular a passenger car, which does not have such a conventional sun visor.

[0095] Also shown is the use of a tinted or colored area of ​​an intermediate layer to connect a functional element with electrically controllable optical properties to an outer or inner pane of a windshield, whereby the tinted or colored area of ​​the intermediate layer and the functional element together create an electrically controllable sun visor. It is understood that the tinted or colored area can also cover the entire surface and encompass the entire intermediate layer.

[0096] The invention is explained in more detail with reference to a drawing and exemplary embodiments. The drawing is a schematic representation and not to scale. The drawing does not limit the invention in any way. It shows: Figure 1 is an enlarged view of a section of a functional element, Figure 2A is a top view of a composite disc according to the invention, Figure 2B is a cross-section through the composite disc made of Figur 2A along the section line X-X', Figure 3A, 3B, 3C depicts the individual process steps for manufacturing a functional element and Figure 4 shows an embodiment of the process using a flowchart.

[0097] Figur 1 Figure 1 shows an enlarged representation of a section of a functional element 5 in the area of ​​a side edge 5.1 of the functional element.

[0098] The controllable functional element 5 is, for example, a PDLC multilayer film consisting of an active layer 11 arranged between a first surface electrode 12 and a second surface electrode 13. The first surface electrode 12 has a first support film 14 on its surface facing away from the active layer 11, which stabilizes the surface electrode 12. The second surface electrode 13 has a second support film 15 on its surface facing away from the active layer 11, which also stabilizes the second surface electrode 13. The active layer 11 contains a polymer matrix with dispersed liquid crystals that align themselves depending on the electrical voltage applied to the surface electrodes 12 and 13, thereby controlling the optical properties. The support films 14 and 15 are made of PET and have a thickness of, for example, 0.14 mm.The carrier films 14, 15 are provided with an ITO coating of approximately 100 nm thickness facing the active layer 11, which forms the surface electrodes 12, 13. The surface electrodes 12, 13 are applied, for example, by a known sputtering process. The surface electrodes 12, 13 can be connected to the vehicle's electrical system via busbars (not shown, for example, formed by a silver-containing screen print) and connecting cables (not shown).

[0099] In the illustrated embodiment, the second carrier film 15 is extended compared to the first carrier film 14, which is also referred to below as the overhang or projecting area 15.1. In other words, the second carrier film 15 extends beyond the first carrier film 14 in the plane of the functional element 5.

[0100] A barrier film 4 is arranged and bonded over its entire surface in the projecting area 15.1 at the side edge 5.1 on the second carrier film 15 and in an edge region of width w on the first carrier film 14. This completely covers and seals the exit surface 20.1 of the active layer 11 at the side edge 5.1. The barrier film 4 is located on the inner surface of the second carrier film 15 and on the edge region 14.1 of the outer surface of the first carrier film 14. The inner surface and outer surfaces of the carrier films refer to the surfaces relative to the functional element 5.

[0101] In this example, further barrier films 4 are arranged on protruding areas of the second carrier film on all side edges of the functional element (in Figur 1 (not shown).

[0102] Figur 2A und Figur 2B Figures 1 and 2 each show a detail of a laminated glass pane 100 according to the invention. The laminated glass pane 100 comprises an outer pane 1 and an inner pane 2, which are bonded together via a first intermediate layer 3a and a second intermediate layer 3b. The outer pane 1 has a thickness of 2.1 mm and is made, for example, of clear soda-lime glass. The inner pane 2 has a thickness of 1.6 mm and is also made, for example, of clear soda-lime glass. The laminated glass pane 100 has a first edge designated D, which is hereinafter referred to as the upper edge. The laminated glass pane 100 has a second edge designated M, which is arranged opposite the upper edge D and is hereinafter referred to as the lower edge. The laminated glass pane 100 can, for example, be arranged as architectural glazing in the frame of a window with other panes to form insulating glazing.It goes without saying that the composite disc 100 can also be designed and used as a roof disc for a vehicle or, with appropriate dimensions, as a windshield or similar.

[0103] A functional element 5 is arranged between the first intermediate layer 3a and the second intermediate layer 3b. Its optical properties can be controlled by an electrical voltage. For the sake of simplicity, the electrical leads are not shown.

[0104] The functional element from Figur 1 For example, the enlarged area Z, which will also be referred to below, is shown here. Figur 3C is reproduced.

[0105] Intermediate layers 3a and 3b each comprise a thermoplastic film with a thickness of 0.38 mm. Intermediate layers 3a and 3b consist, for example, of 78 wt% polyvinyl butyral (PVB) and 20 wt% triethylene glycol bis(2-ethylhexanoate) as a plasticizer.

[0106] The second carrier film 15, for example, has an overhang u of, say, 5 mm on all sides beyond the first carrier film 14. "On all sides" here means that there is an overhang u over each side edge 5.1, 5.2, 5.3, 5.4 of the functional element 5. A one-piece barrier film 4, for example frame-shaped, is arranged on the overhanging area 15.1 of the second carrier film 15 and on an edge area 14.1 of width w of the first carrier film 14 and is connected to them. The frame-shaped barrier film 4 seals the exit surface 20.1 of the active layer 11 on all sides.

[0107] It is understood that the exit surfaces of the active layer between the second carrier film and the first carrier film at the individual side edges 5.1, 5.2, 5.3, 5.4 can also be covered and sealed with one or more strip-shaped barrier films.

[0108] For example, barrier film 4 consists essentially of PET, that is, at least 97 wt%. Barrier films 4a, 4b contain less than 0.5 wt% plasticizer and are suitable for reducing or preventing the diffusion of plasticizer from the intermediate layers 3a, 3b via the side edges 5.1, 5.2, 5.3, 5.4 into the active layer 11 of the functional element 5.

[0109] In aging tests, such composite discs 100 show a significantly reduced brightening in the edge area of ​​the functional element 5, since diffusion of the plasticizer from the intermediate layers 3a, 3b into the functional element 5 and a resulting degradation of the functional element 5 is avoided.

[0110] In an advantageous embodiment of the functional element 5, an adhesive, for example an acrylate-based adhesive, is placed between the barrier film 4 and the contacting sections of the second carrier film 15 and the edge region 14.1 of the first carrier film 14. This adhesive firmly bonds the barrier film 4 to the carrier films 14 and 15. The adhesive bond prevents the barrier film 4 from slipping during assembly. At the same time, it prevents the formation of air bubbles and the resulting optical defects or impairments, as the barrier film 4 lies firmly against both the second carrier film 15 and the first carrier film 14.

[0111] It is understood that the composite disc according to the invention is not limited to the embodiment shown here. Further embodiments not shown here include, for example, windshields or roof windows of vehicles, and the use of electrically controllable functional elements 5 as sun visors.

[0112] Figur 3A, 3B und 3C show design examples of functional element 5 during manufacturing.

[0113] Figur 4 shows an exemplary embodiment of the manufacturing process using a flowchart with process steps S1 to S3.

[0114] In a first process step S1, a stacking sequence consisting of a first carrier film 14, a first surface electrode 12, an active layer 11, a second surface electrode 13 and a second carrier film 15 is provided.

[0115] Such stacked sequences are commercially available as multi-layer film material sold by the meter. The material is then cut to size and trimmed to the dimensions required for its intended use, for example by laser cutting.

[0116] Figur 3A Figure 5 shows an enlarged view of the side edge 5.1 of such a stacking sequence. The various elements of the stacking sequence, namely the first carrier film 14, the first surface electrode 12, the active layer 11, the second surface electrode 13 and the second carrier film 15, have the same dimensions and are stacked congruently on top of each other.

[0117] In a second step S2, for example, the first carrier film 14 is trimmed back by a section of width u on at least one side edge (here 5.1), thus forming a protruding section 15.1 of the second carrier film 15. The result is accordingly shown in Figur 3B depicted.

[0118] In a third process step S3, a barrier film 4 is placed on the protruding area 15.1 of the second carrier film 15, the exit surface 20.1 of the active layer 11, and an adjacent edge area (14.1) of width w of the first carrier film (14). The result is shown accordingly in Figur 3C depicted.

[0119] The barrier film 4 can optionally be connected to the first carrier film 14, for example by gluing, melting or welding, either sectionally or over the entire surface.

[0120] Independently of this, by lamination of the functional element 5 in a composite pane 100 and by the internal pressure in the finished laminated composite pane 100, the barrier film 4 is firmly pressed and fixed onto the first carrier film 14 and the second carrier film 15, thereby creating a hermetic seal. Reference symbol list:

[0121] 1 Outer pane 2 Inner pane 3 First intermediate layer 3 Second intermediate layer 4 Barrier film 5 Functional element with electrically controllable optical properties 5.1, 5.2, 5.3, 5.4 Side edge of the functional element 5 11 Active layer of the functional element 5 12 First surface electrode of the functional element 5 13 Second surface electrode of the functional element 5 14 First carrier film 14.1 Edge area of ​​the first carrier film 14 15 Second carrier film 15.1 Protruding area of ​​the second carrier film 15 16 Insulation lines 20.1 Exit surface 100 Composite pane B Central field of vision of the windshield D Upper edge of the windshield, roof edge M Lower edge of the windshield, engine edge u Overhang, width of the protruding area 15.1 w Width of the edge area 14.1 S1, S2, S3 Procedure steps X-X' Section line Z Enlarged area

Claims

1. Composite pane (100), comprising a stack sequence formed of an outer pane (1), a first intermediate layer (3a), a second intermediate layer (3b), and an inner pane (2), wherein the intermediate layers (3a, 3b) contain at least one thermoplastic polymer film with at least one plasticizer, and a functional element (5) having electrically controllable optical properties is arranged between the first intermediate layer (3a) and the second intermediate layer (3b) at least in sections, wherein the functional element (5) comprises: a stack sequence formed of a first carrier film (14), a first surface electrode (12), an active layer (11), a second surface electrode (13), and a second carrier film (15), wherein the second carrier film (15) has an overhanging region (15.1) beyond the first carrier film (14) and a barrier film (4) is arranged on at least one edge region (14.1) of the first carrier film (14) and the overhanging region (15.1) of the second carrier film (15), wherein the barrier film is arranged in the overhanging region on an inward surface of the second carrier film (15), wherein, in the overhanging region (15.1), the barrier film (4) and the second carrier film (15) are joined to one another at least in sections or over their entire surface, wherein the barrier film (4) is preferably materially and / or form-fittingly bonded to the inward surface of the second carrier film, particularly preferably fused and / or glued to one another, wherein the barrier film (4) does not touch the outward surface of the second carrier film (15), and wherein, in the edge region (14.1), the barrier film (4) and the first carrier film (14) are joined to one another in sections or over their entire surface, wherein the barrier film (4) is preferably materially and / or form-fittingly bonded to an outward surface of the first carrier film, particularly preferably fused and / or glued, wherein an exit surface (20.1) of the active layer (11) between the first carrier film (14) and the second carrier film (15) is sealed by the barrier film (4).

2. Composite pane (100) according to claim 1, wherein the overhang u is arranged at least at one side edge (5.1), preferably at three side edges (5.1, 5.2, 5.3), and particularly preferably at all side edges (5.1, 5.2, 5.3, 5.4) of the second carrier film (15).

3. Composite pane (100) according to claim 1 or claim 2, wherein the overhang u is at least 4 mm, preferably 6 mm, particularly preferably from 6 mm to 20 mm, and in particular preferably 8 mm to 10 mm.

4. Composite pane (100) according to one of claims 1 through 3, wherein the active layer (11) contains or is made of liquid crystals, preferably polymer dispersed liquid crystals (PDLC).

5. Composite pane (100) according to one of claims 1 through 4, wherein the intermediate layer (3a,3b) contains at least 3 wt.-%, preferably at least 5 wt.-%, particularly preferably at least 20 wt.-%, even more preferably at least 30 wt.-%, and in particular at least 40 wt.-% of a plasticizer and the plasticizer preferably contains or is made of aliphatic diesters of tri- or tetraethylene glycol, particularly preferably triethylene glycol bis(2-ethylhexanoate).

6. Composite pane (100) according to one of claims 1 through 5, wherein the intermediate layer (3a,3b) contains at least 60 wt.-%, preferably at least 70 wt.-%, particularly preferably at least 90 wt.-%, and in particular at least 97 wt.-% polyvinyl butyral (PVB).

7. Composite pane (100) according to one of claims 1 through 6, wherein the barrier film (4) is implemented such that it prevents the diffusion of plasticizer through the barrier film (4).

8. Composite pane (100) according to one of claims 1 through 7, wherein the barrier film (4) is low in plasticizer or free of plasticizer and preferably contains or is made of polyethylene terephthalate (PET) or polyvinyl fluoride (PVF).

9. Composite pane (100) according to one of claims 1 through 8, wherein the functional element (5) is circumferentially surrounded by a third intermediate layer (3c).

10. Method for producing a composite pane (100) according to one of claims 1 through 9, wherein at least a) one outer pane (1), one first intermediate layer (3a), one functional element (5) having electrically controllable optical properties, one second intermediate layer (3b), and one inner pane (2) are arranged one atop another in this order, b) the outer pane (1) and the inner pane (2) are joined by lamination, wherein an intermediate layer with an embedded functional element (5) is formed from the first intermediate layer (3a) and the second intermediate layer (3b).

11. Method according to claim 10, wherein the electrical contacting of surface electrodes (12, 13) of the functional element (5) is done before the lamination of the composite pane (100).

12. Method according to one of claims 10 or 11, wherein for producing the functional element (5) having electrically controllable optical properties at least: a) a stack sequence formed of a first carrier film (14), a first surface electrode (12), an active layer (11), a second surface electrode (13), and a second carrier film (15) is provided, b) the first carrier film (14) is cut back at at least one side edge (5.1) by a region of the width u, by which means an overhanging region (15.1) of the second carrier film (15) is formed, and c) a barrier film (4) is arranged on the overhanging region (15.1), an exit surface (20.1) of the active layer (11), and an adjacent edge region (14.1) of the first carrier film (14).

13. Method according to claim 12, wherein at least in one region of another side edge, the second carrier film (15) is cut back, by which means an overhanging region of the first carrier film (14) is formed, and another barrier film (4) is arranged on the overhanging region, the exit surface (20.1) of the active layer (11), and an adjacent edge region of the second carrier film (15).

14. Use of the composite pane (100) according to one of claims 1 through 9 as interior glazing or exterior glazing in a vehicle or a building and the electrically controllable functional element (5) as a sun screen, as thermal protection or as a privacy screen, in particular as a windshield or roof panel of a vehicle, wherein the electrically controllable functional element (5) is used as a sun visor.