Composite lens with functional element with electrically controllable optical properties

Description

[0001] The invention relates to a composite glass with a functional element having electrically controllable optical properties and in particular a windshield with an electrically controllable sun visor.

[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. 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. 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, increasing the transmission of light through the active layer. The PDLC functional element works less by reducing the overall transmission and more by increasing scattering to ensure glare control. Such functional elements are known, for example, from DE 202018102520 U1.

[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 2007 / 122429 A1.

[0007] 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.

[0008] 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. Further aspects of the invention include its uses.

[0009] A functional element with electrically controllable optical properties 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, where the second carrier film is folded around the first carrier film at least on one side edge.

[0010] In the functional element, the second carrier film seals an exit surface of the active layer at the respective side edge.

[0011] 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.

[0012] By folding the second carrier film around the side edge of the first carrier film, the inner surface of the second carrier film is positioned in the folded area in close proximity to the outer surface of the first carrier film.

[0013] In an advantageous further development of the functional element, the second carrier film has a projection over the first carrier film; that is, the second carrier film has a projecting area with width u. In other words, the second carrier film is wider in this area.

[0014] The terms "overhang" and "protrude" mean, as is commonly used, to extend beyond something in a lateral (horizontal) direction. In this case, the second carrier film extends beyond the first carrier film in the plane of the functional element. "Lateral" here means, as is commonly used, to the side or to the side. To simplify the description, the entire area by which the second carrier film is longer than the first is referred to as the overhanging area, even if the overhanging area extends out of the lateral plane and is folded around the side edge of the first carrier film. This folding can be done manually or automatically, for example, by a robot.

[0015] The protruding area advantageously has a width u of at least 4 mm, preferably of at least 6 mm and particularly preferably of at least 8 mm.

[0016] The projecting area advantageously has a maximum width u of 50 mm, preferably 20 mm, and particularly preferably 10 mm. A projecting area with a width u of 0.5 mm to 50 mm is particularly advantageous.

[0017] Alternatively, the protruding area u of the second carrier film can be wider than the entire first carrier film, so that the folded-over area of ​​the second carrier film completely covers the outer surface of the first carrier film and preferably extends beyond the side edge opposite the fold or, more preferably, is folded around it again.

[0018] In the functional element, the protruding and folded area is connected to an edge area of ​​the first carrier film in a material-bonded and / or form-bonded manner, preferably fused and / or glued.

[0019] In an advantageous further development of the functional element, the width w of the folded area connected to the edge of the first carrier film is approximately equal to the width of the overhang u minus the sum of the thickness of the first carrier film, the thickness of the first surface electrode, the thickness of the active layer, and the thickness of the second surface electrode. This results in the second carrier film lying close to the exit surface of the active layer and the side edge of the first carrier film in the overhanging area, thus sealing the exit surface particularly well and ideally hermetically.

[0020] It is understood that the functional element can have a folded-over seal on at least one side edge, preferably on two, three, four or all side edges. For the seal to function, it is irrelevant whether only the second carrier film has a protruding area on one or more side edges, or whether, alternately, at least one first carrier film also has a protruding area that is folded around the second carrier film.

[0021] A composite disk according to the invention comprises at least: a stacking sequence consisting of an outer disk, a first intermediate layer, a second intermediate layer and an inner disk, wherein the intermediate layers each contain at least one thermoplastic polymeric film with at least one plasticizer, and wherein a functional element with electrically controllable optical properties is arranged at least sectionally between the first intermediate layer and the second intermediate layer.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] In the composite disc according to the invention, the inner, folded areas of the second carrier film and the outer edge of the first carrier film are connected to each other, preferably pressed together (for example by lamination in a composite disc), glued or welded (for example by local heating). 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.

[0028] In a further advantageous embodiment of a laminated glass pane according to the invention, the inner, folded areas of the second carrier film and the outer edge of the first carrier film are fully bonded together and preferably glued, for example by an adhesive, in particular by an acrylic-based adhesive, preferably an acrylate-based adhesive, and most preferably an adhesive containing more than 50% methyl methacrylate. This has the particular advantage that slippage during assembly and lamination is prevented and the second carrier film is firmly and closely bonded to the first carrier film. This prevents, among other things, air inclusions and results in a particularly high optical quality for such functional elements and laminated glass panes.

[0029] 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 brightening or alteration of transmission during aging, which impairs the transparency and aesthetics of the laminated glass. By sealing the exit surface of the active layer of the functional element with the carrier film, which inhibits or prevents the diffusion of plasticizers from the intermediate layer into the functional element and, in particular, into the exit surface of the active layer, such aging effects are significantly reduced or completely prevented.

[0030] In an advantageous embodiment of a composite disk according to the invention, the intermediate layer contains a polymer, preferably a thermoplastic polymer.

[0031] In a particularly advantageous embodiment of a 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).

[0032] 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 .

[0033] In a further particularly advantageous embodiment of a 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.

[0034] 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.

[0035] The controllable functional element comprises an active layer between two surface electrodes. This active layer exhibits controllable optical properties, which can be adjusted via the voltage applied to the surface electrodes. The surface electrodes and the active layer are typically arranged substantially parallel to the surfaces of the functional element and, in a composite disk, substantially 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 through suitable connecting cables, such as foil conductors, which are optionally connected to the surface electrodes via busbars, for example, strips of electrically conductive material or electrically conductive imprints.

[0036] 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.

[0037] 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.

[0038] 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 carrier films that form the two surfaces of the multilayer film. This allows the functional element to be provided as a laminated film, which is advantageously processable. The carrier films provide the functional element with advantageous protection against 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.

[0039] 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 0.05 mm to 0.2 mm.

[0040] The carrier films each have an electrically conductive coating that faces the active layer and acts as a surface electrode.

[0041] In a further advantageous embodiment of a 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 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.

[0042] 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.

[0043] 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 that a carrier film, including the surface electrode, will detach from the functional layer, which is visually noticeable and negatively affects the aesthetics of the disc.

[0044] 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.

[0045] 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.

[0046] In an advantageous embodiment of a 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.

[0047] To enhance functionality, an intermediate layer can also consist of three individual layers for acoustically optimized discs. In such cases, the intermediate layer is 0.05 mm to 0.2 mm thicker.

[0048] Another alternative is thermal improvement through an IR-reflective coated PET interlayer. In this case, the outward-facing interlayer also consists of at least three interlayers (PVB-PET-PVB). The IR-reflective coating can be oriented inwards or outwards.

[0049] 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.

[0050] 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 (e.g., a windshield), such as 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.

[0051] 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.

[0052] 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.

[0053] The tinted or colored area can be homogeneously colored or tinted, meaning it exhibits 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.

[0054] 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 impression 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.

[0055] In an advantageous embodiment, either the inner and / or the outer pane can be tinted. This results in a visually appealing laminated glass pane. Particularly for vehicle openings where transparency is not limited, such as in the roof area, a visually pleasing laminated glass pane can be achieved.

[0056] The composite glass with electrically controllable functional element can advantageously be designed as a windshield with an electrically controllable sun visor.

[0057] 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.

[0058] 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 one 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.

[0059] 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 located 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.

[0060] The windshield is preferably intended for a motor vehicle, especially preferably for a passenger car.

[0061] 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 positioned.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.

[0062] The side edges of the functional element visible through the windshield are preferably arranged 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.

[0063] 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.

[0064] 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.

[0065] The insulation lines have a width of, for example, 5 µm to 500 µm, and 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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).

[0072] 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.

[0073] Another aspect of the invention also includes a method for manufacturing a composite disk according to the invention, wherein at least a) an outer disk, a first intermediate layer, a functional element with electrically controllable optical properties, a second intermediate layer and an inner disk are arranged one above the other in this order, b) the outer disk and the inner disk are joined by lamination, whereby an intermediate layer with an embedded functional element is formed from the first intermediate layer and the second intermediate layer.

[0074] The electrical contacting of the surface electrodes of the functional element preferably takes place before laminating the composite disc.

[0075] Any existing prints, such as opaque cover prints or printed conductors for electrical contacting the functional element, are preferably applied using screen printing.

[0076] 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.

[0077] 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 or a building, wherein the electrically controllable functional element is used as sun protection, as thermal protection or as privacy protection.

[0078] The invention further comprises the use of a composite 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.

[0079] 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.

[0080] 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, 3D representations of the individual process steps for the production of a functional element and Figure 4 an embodiment of the process based on a flowchart.

[0081] 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.

[0082] 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).

[0083] 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 the projecting area 15.1, the second carrier film 15 is folded around the first carrier film 14 at the side edge 5.1. This completely covers and seals the exit surface 20.1 of the active layer 11 at the side edge 5.1. The exit surface 20.1 here designates the area of ​​the active layer 11 that extends between the first and second carrier films 14, 15 with the first and second surface electrodes 12, 13 along the side edge 5.1 of the functional element 5, and at which the active layer 11 has access to the surroundings of the functional element 5 without the surrounding projecting area 15.1 of the second carrier film 15. The inner surface of the second carrier film 15 is thus on the edge area 14.1 of the outer surface of the first carrier film 14. The inner surface of the carrier films and the outer surfaces of the carrier films refer to the surfaces relative to the functional element 5.

[0084] The width w of the edge area 14.1, i.e. the contact area of ​​the inner surface of the second carrier film 15 and the outer surface of the first carrier film 14, is, for example, 10 mm and extends essentially with a constant width over the entire length of the side edge 5.1.

[0085] Figur 2A und Figur 2B Figures 1 and 2 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 used as architectural glazing in the frame of a window with other panes to form insulating glass, or as a roof pane in the roof of a vehicle.It is understood that partition wall panels, side windows or rear windows can also be advantageously designed according to the invention.

[0086] 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.

[0087] The functional element from Figur 1 For example, the enlarged area Z, which will also be referred to below, is shown here. Figur 3D is reproduced.

[0088] 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.

[0089] In this embodiment, three side edges 5.1, 5.2, 5.3 have a seal according to the invention by means of the respective folded-over second carrier film 15. The fourth side edge 5.4 has a seal according to the invention by means of a folded-over first carrier film 14.

[0090] 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.

[0091] In an advantageous embodiment of the functional element 5, an adhesive, for example an acrylate-based adhesive, is placed between the contacting sections of the second carrier film 15 and the edge region 14.1 of the first carrier film 14, which firmly bonds the carrier films 14, 15 together. The adhesive bond prevents the carrier films 14, 15 from slipping during assembly. At the same time, the inclusion of air bubbles and the resulting optical distortions or defects are avoided, since the folded section of the second carrier film 15 lies firmly on the first carrier film 14.

[0092] 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.

[0093] Figur 3A, 3B, 3C und 3D show design examples of a functional element 5 during manufacturing.

[0094] Figur 4 shows an exemplary embodiment of the manufacturing process using a flowchart with process steps S1 to S4.

[0095] In a first process step S1, a stack 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 initially prepared. Such stack sequences are commercially available, for example, as multilayer film material sold by the meter. Subsequently, the material is cut to size and trimmed to the dimensions required for later use, for example, by laser cutting.

[0096] Figur 3A Figure 5 shows an enlarged representation of the side edge 5.1 of such a stacking sequence in the first process step S1. The various elements of the stacking sequence, i.e. 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.

[0097] In a second step S2, for example, the first carrier film 14 is trimmed back by a region of width u at least on one side edge and preferably on all side edges of the stacking sequence, thereby forming a protruding region 15.1 of the second carrier film 15. The result for side edge 5.1 is accordingly shown in Figur 3B The cutting back is carried out, for example, by mechanical cutting with a blade along a parallel line at a distance u from the side edge of the first carrier film 14.

[0098] In a third process step S3, the active layer 11 and the second surface electrode 13 in the protruding area 15.1 are removed. The active layer 11 can be removed, for example, by wiping with a cloth and a solvent such as water or ethanol. The result is accordingly shown in Figur 3C The surface electrode 13 can be removed, for example, by laser ablation.

[0099] In a third process step S4, the second carrier film 15 is folded around the cut-back side edge 5.1 of the first carrier film 14 and positioned on the outer surface of the first carrier film 14 in the edge region 14.1. The result is shown accordingly in Figure 3D.

[0100] The second carrier film 15 can optionally be fully bonded to the first carrier film 14, for example by gluing. The folded carrier film 14 should advantageously be free of adhesive in an edge area, for example at least in a width w = 4 mm, as otherwise undesirable edge lightening may occur.

[0101] Regardless, 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 second carrier film 15 and the first carrier film 14 are pressed firmly together and fixed in the edge area 14.1, resulting in a hermetic seal. Reference symbol list:

[0102] 1 Outer pane 2 Inner pane 3 First intermediate layer 3 Second intermediate layer 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 15 Second carrier film 15.1 Protruding area of ​​the second carrier film 20.1 Exit surface 100 Composite pane D Top edge of the windshield, roof edge M Bottom edge of the windshield, engine edge u Overhang, width of the protruding area 15.1 w Width of the edge area 14.1 X-X' Section line Z Enlarged area

Claims

1. Composite pane (100) having a functional element (5) having electrically controllable optical properties, 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 - at least in sections between the first intermediate layer (3a) and the second intermediate layer (3b) a functional element (5) having electrically controllable optical properties is arranged, 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) is folded around the first carrier film (14) at least at one side edge (5.1) and seals an exit surface (20.1) of the active layer (11) at the side edge (5.1), - at least one section of an overhanging region (15.1) is materially bonded to an edge region (14.1) of the first carrier film (14), is permanently pressed together, is fused, and / or is glued, and - the carrier films (14,15) are implemented such that they prevent diffusion of plasticizers through the carrier film (14,15), wherein the carrier films (14, 15) are low in plasticizer or are free of plasticizer.

2. Composite pane (100) according to claim 1, wherein the overhanging region (15.1) of the second carrier film (15) has at least a width u of 4 mm and preferably of 4 mm to 50 mm.

3. Composite pane (100) according to one of claims 1 or 2, wherein the active layer (11) contains or is made of liquid crystals, preferably polymer dispersed liquid crystals (PDLC).

4. Composite pane (100) according to one of claims 1 to 3, 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).

5. Composite pane (100) according to one of claims 1 to 4, 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).

6. Composite pane (100) according to one of claims 1 to 5, wherein the carrier films (14, 15) contain or are made of polyethylene terephthalate (PET) or polyvinyl fluoride (PVF).

7. Composite pane (100) according to one of claims 1 to 6, wherein the functional element (5) is circumferentially surrounded by a third intermediate layer.

8. Use of a composite pane (100) according to one of claims 1 through 7 as a windshield or roof panel of a vehicle and the electrically controllable functional element (5) as a sun visor.

9. Use of a composite pane (100) having an electrically controllable functional element (5) according to one of claims 1 through 7 as interior glazing or exterior glazing in a vehicle or a building and the electrically controllable functional element (5) as a sunscreen or as a privacy screen.

10. Method for producing a composite pane (100) having a functional element (5) having electrically controllable optical properties according to one of claims 1 to 7, wherein at least a) one outer pane, one first intermediate layer, one functional element having electrically controllable optical properties, one second intermediate layer, and one inner pane are arranged one atop another in this order, b) the outer pane and the inner pane 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.