Functional element with electrically controllable optical properties

Abstract

A functional element (5) with electro-controllable optical properties having multiple side edges (4.1, 4.2, 4.3, 4.4) includes at least a first carrier film (14) having a first planar electrode (12) and a second carrier film (15) having a second planar electrode (13), and an active layer (11) arranged in a planar form between the first planar electrode (12) and the second planar electrode (13), wherein - a first busbar (18) and a second busbar (19) are arranged on at least one first side edge (4.1), - the first carrier film (14) has at least one first groove (10.1) and the second carrier film (15) has At least one second groove (10.2), wherein - a first busbar (18) is disposed on the surface of the second carrier film (15) opposite to the second planar electrode (13), passes through it in the region of the at least one second groove (10.2), and is in conductive contact with the first planar electrode (12); - a second busbar (19) is disposed on the surface of the first carrier film (14) opposite to the first planar electrode (12), passes through it in the region of the at least one first groove (10.1), and is in conductive contact with the second planar electrode (13); and - the busbars (18, 19) are divided into segments that can be controlled independently of each other.

Description

[0001] The present invention relates to a functional element having electro-controllable optical properties, a method for gradually switching the functional element, and a composite glass plate including such a functional element.

[0002] To protect the driver or other passengers from glare, conventional motor vehicles have mechanical sun visors. These are foldable or movable and mounted on the top of the vehicle, and can be folded down or pulled up as needed to prevent or at least reduce glare for the driver or passengers.

[0003] Windshields and roof glass panels are also known, where sun visors are integrated as functional elements with electrically adjustable optical properties, particularly electrically adjustable transmission or scattering behavior. In this way, the driver can control the transmission behavior of the glass itself to solar radiation, eliminating the need for traditional mechanical sun visors. As a result, the weight of the vehicle can be reduced, and more space can be gained in the top area. Furthermore, the electrical adjustment of the sun visor makes it more convenient for the driver. Especially in the case of large panoramic glass panels, variable control of the glass's transmission in the top area is also required. Depending on the sun's position, only a sub-area of ​​the glass panel needs to be shaded, or the entire area can be switched to opaque as a privacy screen for parked vehicles.

[0004] Possible electrically switchable functional elements for realizing adjustable sun visors are electrochromic functional elements and PDLC functional elements. Polymer Dispersed Liquid Crystal SPD functional elements ( Suspended Particle Device This includes electroluminescent functional elements. The operating principle of such functional elements is known to those skilled in the art. The mentioned functional elements typically comprise two carrier films on which planar electrodes are disposed, with an active layer introduced between the carrier films directly adjacent to the planar electrodes. The optical properties of the active layer change depending on the voltage applied to the planar electrodes. To achieve gradual or segmented changes in optical properties, locally or segmentally different voltages must be applied to the planar electrodes, thus adjusting the electrical contacts accordingly.

[0005] Electrical contacts of electrically controllable functional elements are typically established via busbars (also known as “buses”) that are applied to and conductively contacted with planar electrodes in the edge regions of the functional element. Voltage is applied to the planar electrodes and the active layer of the functional element is switched by connecting the busbar to an external voltage source, such as through flat conductors mounted on the busbar. The smaller the area of ​​each electrically controllable region, the more complex and intricate the electrical contacts become.

[0006] EP 2416385 A1 relates to a back contact film having multiple sublayers and a method for using it to connect solar cells.

[0007] EP 1840449 A1 describes a light panel comprising a glass substrate, a conductive coating, and a plurality of LEDs, wherein the LEDs are electrically contacted through conductors in the conductive coating, and two buses are arranged on the same edge of the light panel.

[0008] WO 2020 / 083563 A1 and WO 2020 / 083562 A1 disclose a composite glass plate having segmentally switchable electrically controllable functional elements, having a first set of buses in electrical contact with segments introduced into a first planar electrode and at least one second bus in electrical contact with a second planar electrode.

[0009] The object of the present invention is to provide a switchable functional element with electro-controllable optical properties, which has improved electro-control including step-by-step switchable features.

[0010] The object of the present invention is achieved by a functional element having electro-controllable optical properties as described in independent claim 1. Preferred embodiments are given in the dependent claims.

[0011] The functional element according to the invention includes an active layer located between a first planar electrode and a second planar electrode. The active layer has adjustable optical properties, which can be controlled by a voltage applied to the planar electrode. The planar electrode is applied onto a carrier film. The planar electrode, active layer, and carrier film are generally arranged substantially parallel to each other. The planar electrode is electrically connected to a bus through which the functional element can be connected to an external voltage source. The active layer is arranged in a planar form between the first and second planar electrodes. The functional element includes a plurality of side edges, wherein the first and second buses are arranged on at least one first side edge. The first bus is in conductive contact with the first planar electrode, and the second bus is in conductive contact with the second planar electrode. Here, the first carrier film includes at least one first groove in which material of the first carrier film and the first planar electrode thereon is removed. The second bus is disposed on the surface of the first carrier film opposite to the active layer and the first planar electrode. The second bus passes through the first groove and is in electrical contact with the second planar electrode in that region. Here, the active layer is not present in the region of the first groove, and the second bus is in direct electrical contact with the second planar electrode. A first bus extends on the surface of the second carrier membrane opposite to the active layer and the second planar electrode. The second carrier membrane includes at least one second groove within which material of the second carrier membrane and the second planar electrode located thereon is removed. The first bus passes through the second carrier membrane in the second groove region and makes electrical contact with the first planar electrode. Here, there is no active layer in the second groove region, and the first bus makes direct electrical contact with the first planar electrode in this region. At least one of these buses is divided into at least one first segment and at least one second segment. Therefore, the first bus is divided into at least one first segment and at least one second segment, and / or the second bus is divided into at least one first segment and at least one second segment. These segments of the first bus can be controlled independently of each other. The same applies to the segments of the second bus.

[0012] Adjacent sections of the busbar are preferably separated from each other by a separator line, wherein the region of the separator line contains the conductivity of an insulator and no current flows between adjacent sections of the busbar. This allows for targeted control of the areas containing functional elements. The busbar can be initially positioned along at least one side edge and then divided into at least two sections, thus eliminating the need to apply these sections individually.

[0013] The functional element according to the invention simplifies the electrical contact of planar electrodes in the edge region. Buses are respectively applied to the surfaces of the carrier film opposite to the planar electrodes and partially penetrate the nearest carrier film in the groove region to achieve electrical contact on the planar electrodes away from their respective buses. In this way, the first bus and the second bus can be jointly disposed on the first side edge. As a result, the number of side edges that must be contacted can be reduced.

[0014] Dividing one or two buses into electrically isolated segments allows for selective, segment-by-segment switching of the active layer, where the selectively switchable region of the active layer is located within the area of ​​the planar electrode where voltage is applied by the bus. To selectively control individual regions of the functional element, the opposite terminal of a voltage source is connected to the respective segments of the buses of the first and second planar electrodes, depending on the desired switching of the active layer. The first terminal of the voltage source is connected to a segment of the second bus, while the opposite terminal is connected to a segment of the first bus; these segments contact the region of the first planar electrode to be controlled. Therefore, the potential difference between the planar electrodes exists only in the regions of the functional element where the corresponding region of the first planar electrode is connected to the voltage source. Thus, the active layer of the functional element is switched only in these regions. Targeted control of the segments of the first planar electrode to which voltage is applied is achieved, for example, by an external control unit.

[0015] The first and second grooves are arranged alternately with each other. Therefore, there are at least one first groove and at least two second grooves, or at least two first grooves and at least one second groove, to ensure an alternating arrangement along the first side edge. Preferably, there are at least two first grooves and at least two second grooves, which are arranged alternately with each other along the first side edge. This alternating arrangement of grooves allows for targeted control of all planar areas of the functional element, with accuracy increasing as the number of first and second grooves increases.

[0016] The functional element has multiple side edges, particularly preferably four side edges. However, the functional element may also include more than four side edges. Each of the at least two side edges of the functional element is substantially paired and opposite to each other. In embodiments with four side edges, this creates two pairs, each formed by two opposing side edges. The opposing side edges of the functional element may extend parallel or non-parallel to each other. The side edges need not be straight, but are generally curved. The lengths of the opposing side edges may differ from each other. For example, the functional element may have a trapezoidal profile. In a preferred embodiment, the functional element has multiple side edges, such as four side edges.

[0017] In a preferred embodiment of the functional element, at least one additional first bus and / or second bus is arranged at least on the second side edge. The presence of at least one additional bus results in a more uniform voltage distribution, thereby improving the switching process of the functional element. In the sense of uniform voltage distribution, the buses are particularly arranged on the opposing side edges of the functional element. The first and second buses are particularly preferably arranged on at least one second side edge, wherein contact between the buses and the associated planar electrodes is achieved via first and second recesses. The first and second recesses are thus positioned along the second side edge, similar to the possible arrangement on the first side edge, wherein the arrangement on the first side edge and the arrangement on the second side edge are distinguishable within the functional element.

[0018] This invention enables the first and second buses to be jointly positioned on the side edge of a functional element. Thus, other side edges of the functional element can remain without buses if desired. This is advantageous, for example, if the functional element does not extend across the entire surface of the mounting glass and its edge lies within the transparent area of ​​the mounting glass. On this side edge, the second bus is omitted for aesthetic purposes.

[0019] Preferably, the functional element has a first bus and a second bus along its first, second, third, and fourth side edges, respectively. In this way, the switching behavior can be made as uniformly as possible when switching simultaneously across all regions of the functional element. On the other hand, very precise control can be achieved for each region during step-by-step switching of the functional element.

[0020] In one possible implementation, the first planar electrode and / or the second planar electrode includes at least one separator line that divides the functional element into regions (also referred to as segments) that can be switched independently of each other. The separator line may also be referred to as an insulating line and electrically isolates the individual segments of the planar electrode from each other. In the context of this invention, a separator line is understood as a non-conductive linear region within the planar electrode that extends across the entire thickness of the planar electrode. The separator lines between the individual segments of the planar electrode ensure that no current flows through any segment of the coating other than the controlled segment. The width of a segment of the planar electrode is defined by the distance between one or more separator lines that define the segment width. The segment width is here measured along the direction in which the shortest relevant segment of the busbar extends.

[0021] The at least one dividing line preferably extends in a straight line, wavy line, or zigzag line between two opposite edges of the functional element. However, other cutting patterns with one or more dividing lines are also conceivable.

[0022] The segments of the planar electrode are preferably arranged to be substantially parallel to each other, wherein these segments extend coherently from one side edge of the functional element to the opposite side edge.

[0023] The number of segments within the planar electrode can vary depending on the application of the assembled glass, typically ranging from 2 to 20, preferably from 3 to 10.

[0024] Electrical contact between the busbar and the external current source is achieved via a suitable connecting cable, such as a membrane conductor. Suitable external control elements for controlling the individual sections are known to those skilled in the art.

[0025] Functional elements can be electrically adjusted, for example, via buttons, rotary controls, or sliders integrated into, for example, a vehicle's dashboard. However, the switching area for adjustment can also be integrated into a composite glass panel, such as a capacitive switching area. Alternatively, functional elements can be controlled via non-contact methods, such as by recognizing posture or based on pupil or eyelid status determined by a camera and suitable evaluation electronics.

[0026] At least one dividing line is introduced into the planar electrode so that the segments of the planar electrode are electrically insulated from each other. Each segment is independently connected to a voltage source via a section of a busbar, allowing them to be controlled individually. This allows for independent switching of different areas of the functional element. The segments are particularly preferably arranged horizontally in the mounting position. Therefore, the user can adjust the height of the opaque area of ​​the functional element. The term "horizontal" should be interpreted broadly here and refers to the direction of extension extending between the side edges of the composite glass panel, such as the side edges of the windshield or top glass panel. The dividing line does not necessarily have to be straight, but can also be slightly curved, preferably adapting to the possible curvature of the nearest glass panel edge, particularly substantially parallel to the front top edge of the windshield. Vertical insulating lines are also conceivable.

[0027] The separator lines may have a width of, for example, from 5 μm to 500 μm, particularly from 20 μm to 200 μm. The width of the segments, i.e., the distance between adjacent separator lines, can be appropriately selected by those skilled in the art according to the needs of each situation.

[0028] Separators can be introduced during the manufacturing process of functional components via laser ablation, mechanical cutting, or etching. Already laminated multilayer films can also be segmented subsequently using laser ablation.

[0029] Busbars (buses) are connected to planar electrodes, for example, as conductive strips or conductive printouts. The busbars are preferably manufactured as conductive printouts containing silver.

[0030] The functional element can optionally be fabricated as a PDLC element, an SPD functional element, an electrochromic or electroluminescent functional element, wherein the composition of the active layer varies depending on the type of functional element. The mentioned functional elements and their structures are known to those skilled in the art.

[0031] The functional element is preferably an electrochromic functional element, and the active layer is therefore an electrochromic layer. The active layer of the electrochromic functional element is an electrochemically active layer. The transmission of visible light depends on the degree of ion embedding in the active layer, where the ions are provided, for example, by an ion storage layer between the active layer and the planar electrode. Transmission may be affected by the voltage applied to the planar electrode (which causes ion migration). Suitable functional layers, for example, contain at least tungsten oxide or vanadium oxide. Electrochromic functional elements are known, for example, from WO 2012007334 A1, US 20120026573 A1, WO 2010147494 A1, and EP 1862849A1.

[0032] In another implementation, the functional element is a PDLC ( Polymer Dispersed Liquid Crystal PDLC functional elements. The active layer of a PDLC functional element contains liquid crystals embedded in a polymer matrix. If no voltage is applied to the planar electrodes, the liquid crystals align in a disordered manner, resulting in strong scattering of light passing through the active layer. If a voltage is applied to the planar electrodes, the liquid crystals align in a common direction, and the transmission of light through the active layer increases. Such functional elements are known, for example, from DE 102008026339 A1.

[0033] In another implementation, the functional element is an SPD ( Suspended Particle Device A functional element containing an active layer with suspended particles, wherein the absorption of light by the active layer varies by applying a voltage to a planar electrode. The variation in absorption is attributed to the alignment of rod-shaped particles in an electric field when the voltage is applied. SPD functional elements are known, for example, from EP 0876608 B1 and WO2011033313 A1.

[0034] In the case of electroluminescent functional elements, the active layer comprises an electroluminescent material, particularly an organic electroluminescent material, whose luminescence is excited by applying a voltage. Electroluminescent functional elements are known, for example, from US 2004227462 A1 and WO2010112789 A2. Electroluminescent functional elements can be used as simple light sources or as displays that can display arbitrary images.

[0035] The first bus and the second bus include conductive structures, preferably conductive structures containing silver, and have a thickness of 5 μm to 40 μm.

[0036] The bus is configured to be connected to an external voltage source, thereby creating a potential difference between the first planar electrode and the second planar electrode.

[0037] The installation of busbars can be achieved, in particular, by laying, printing, welding or gluing.

[0038] In a preferred embodiment, the bus is designed as a printed and fired conductive structure. The printed bus contains at least one metal, preferably silver. Conductivity is preferably achieved through metal particles contained in the bus, particularly preferably through silver particles. The metal particles may be present in an organic and / or inorganic matrix, such as a paste or ink, preferably as a fired screen-printed paste containing glass frit. The layer thickness of the printed bus is preferably from 5 μm to 40 μm, particularly preferably from 8 μm to 20 μm, and very particularly preferably from 10 μm to 15 μm. Printed buses with these thicknesses are technically easy to implement and have advantageous current-carrying capacity.

[0039] Alternatively, the bus is designed as a strip of conductive film. The bus then comprises, for example, at least aluminum, copper, tin-plated copper, gold, silver, zinc, tungsten, and / or tin or alloys thereof. The strip preferably has a thickness of 10 μm to 500 μm, particularly preferably 30 μm to 300 μm. Buses made of conductive films with these thicknesses are technically easy to implement and have advantageous current-carrying capacity. The strip can be conductively connected to a planar electrode, for example, by solder, by conductive adhesive or conductive tape, or by direct application. To improve the conductive connection, a silver-containing paste can be disposed between the planar electrode and the bus, for example.

[0040] The first and second planar electrodes are each formed of a conductive layer. These conductive layers comprise at least one metal, metal alloy, or transparent conductive oxide, preferably a transparent conductive oxide, and have a thickness of 10 nm to 2 μm. The planar electrodes are preferably transparent. Here, transparent means transparent to electromagnetic radiation, preferably electromagnetic radiation with wavelengths from 300 nm to 1300 nm, and especially transparent to visible light. Conductive layers according to the invention are known, for example, from DE 20 2008 017 611 U1, EP 0 847 965B1, or WO2012 / 052315 A1. They typically comprise one or more, for example, two, three, or four conductive functional monolayers. The functional monolayer preferably comprises at least one metal, such as silver, gold, copper, nickel, and / or chromium, or a metal alloy. The functional monolayer particularly preferably comprises at least 90% by weight of metal, especially at least 99.9% by weight of metal. The functional monolayer may be composed of metal or metal alloy. The functional monolayer particularly preferably comprises silver or a silver-containing alloy. This functional monolayer exhibits particularly advantageous conductivity while also possessing high transmittance in the visible spectrum. The thickness of the functional monolayer is preferably from 5 nm to 50 nm, and particularly preferably from 8 nm to 25 nm. Within this thickness range, both advantageous high transmittance and particularly advantageous conductivity in the visible spectrum are achieved.

[0041] In principle, planar electrodes can be formed from electrically contactable conductive layers.

[0042] The functional element is preferably provided as a multilayer film having two outer carrier films. In such a multilayer film, a planar electrode and an active layer are arranged between the two carrier films. The outer carrier films here refer to the two surfaces of the carrier films forming the multilayer film. Thus, the functional element can be provided as a laminated film that can be advantageously processed. The carrier films advantageously protect the functional element from damage, especially corrosion. The multilayer film comprises at least a first carrier film, a first planar electrode, an active layer, a second planar electrode, and a second carrier film in the order shown.

[0043] The first and / or second carrier films preferably contain at least one polymer that is not completely melted in an autoclave process, preferably polyethylene terephthalate (PET). The first and second carrier films are particularly preferably composed of PET films. This is particularly advantageous for the stability of the multilayer film. However, the carrier films may also contain, for example, ethylene vinyl acetate (EVA) and / or polyvinyl butyral (PVB), polypropylene, polycarbonate, polymethyl methacrylate, polyacrylate, polyvinyl chloride, polyacetate resin, casting resin, acrylate, fluorinated ethylene propylene, polyvinyl fluoride, and / or ethylene tetrafluoroethylene. The thickness of each carrier film is preferably from 0.1 mm to 1 mm, particularly preferably from 0.1 mm to 0.2 mm. The carrier film according to the invention is preferably transparent. The planar electrode is preferably disposed on the surface of the carrier film, i.e., on exactly one of both sides of the carrier film (i.e., on its front or back side). Here, the carrier films are arranged in the multilayer stack such that the planar electrode is arranged adjacent to the active layer.

[0044] In the context of this invention, electrically adjustable optical properties are understood to mean those properties that can be infinitely adjusted, but also those properties that can be switched between two or more discrete states.

[0045] In addition to the active layer and planar electrodes, functional elements may of course have other layers known in themselves, such as barrier layers, anti-reflective layers, protective layers and / or smoothing layers.

[0046] Functional elements for multilayer films are commercially available. These elements are typically cut from a larger multilayer film to the desired shape and size. This can be done mechanically, for example, with a knife. In an advantageous embodiment, cutting is performed by laser. It has been shown that the side edges are more stable in this case than with mechanical cutting. With mechanically cut side edges, there is a risk that the material may appear to recede, which is visually noticeable and detrimental to the aesthetics of the glass sheet.

[0047] In an advantageous embodiment, the functional element has an edge seal. The edge seal surrounds the side edges of the functional element and specifically prevents chemical components of the thermoplastic intermediate layer, such as plasticizers, from diffusing into the active layer. The edge seal is formed of a clear, colorless adhesive or clear, colorless tape, at least along the lower edge of the functional element visible through the windshield and preferably along all side edges. For example, acrylic or silicone-based tapes can be used as edge seals. The advantage of a clear, colorless edge seal is that the edges of the functional element appear unobtrusive when viewed through the windshield. This edge seal is also preferably used for the less visible side edges.

[0048] The present invention also relates to a composite glass plate comprising at least a functional element according to the invention, a thermoplastic interlayer, a first glass plate, and a second glass plate, wherein the thermoplastic interlayer has a first thermoplastic bonding film disposed between the functional element and the first glass plate, and a second thermoplastic bonding film disposed between the functional element and the second glass plate. In this manner, the functional element can be reliably integrated into the composite glass plate via the thermoplastic interlayer.

[0049] The first and second glass plates of the composite glass panel according to the present invention are the inner glass plate and the outer glass plate when the composite glass panel is installed in a motor vehicle or building.

[0050] Functional elements are mounted between a first and a second glass plate in a composite glass panel via an interlayer. The interlayer comprises a first thermoplastic bonding film for bonding the functional element to the first glass plate and a second thermoplastic bonding film for bonding the functional element to the second glass plate. The interlayer is typically formed of at least the first and second thermoplastic bonding films, which are stacked and laminated together in planar form, with the functional element inserted between these two layers. The regions of the bonding films that overlap with the functional element then form the regions that bond the functional element to the glass plates. In other regions of the glass plates where the thermoplastic bonding films are in direct contact with each other, they are fused during lamination such that the two original layers are sometimes no longer identifiable, replaced by a uniform interlayer.

[0051] The thermoplastic bonding film can be formed, for example, from a single thermoplastic film. It can also be formed from segments of different thermoplastic films, with their side edges abutting each other. Other thermoplastic bonding films may be present in addition to the first or second thermoplastic bonding film. These can also be used, if desired, to embed other films including functional layers, such as infrared reflective layers or acoustic damping layers.

[0052] Thermoplastic bonded films may also include colored or tinted regions. Such films can be obtained, for example, by co-extrusion. Alternatively, uncolored film segments and colored or tinted film segments can be combined to form a thermoplastic bonded film. The colored or tinted regions can be uniformly colored or tinted, i.e., having position-independent transmittance. However, the coloring or tinting can also be non-uniform, and in particular, a transmittance distribution can be achieved.

[0053] In one possible implementation, the composite glass panel is a windshield panel for a motor vehicle. The windshield panel includes an upper edge and a lower edge, and two side edges extending between the upper and lower edges. The upper edge refers to the edge positioned upwards toward the top of the vehicle in the mounting position. The upper edge is often referred to as the top edge or the front top edge. The lower edge refers to the edge positioned downwards toward the hood of the vehicle in the mounting position. The lower edge is often referred to as the engine edge.

[0054] The windshield panel provides a central field of view, placing high demands on its optical quality. The central field of view must have high light transmittance (typically greater than 70%). This central field of view is specifically referred to by those skilled in the art as the B-field of view, B-zone, or B-section of the field of view. The B-field of view and its technical requirements are specified in EU Economic Commission Regulation (UN / ECE) No. 43 (ECE-R43, "Uniform Conditions for Approval of Safety-Mounting Glass Materials and Their Installation in Vehicles"). There, the B-field of view is defined in Annex 18.

[0055] In one possible implementation of the windshield panel, the functional element is a sun visor and is positioned above the central field of vision (B-field of vision). This means that the functional element is located in the area between the central field of vision and the front top edge of the windshield panel. The functional element does not need to cover the entire area, but rather is entirely located within that area and does not protrude into the central field of vision. In other words, the functional element has a smaller distance from the top edge of the windshield than the central field of vision. Therefore, the transmission of the central field of vision is not affected by the functional element, which is positioned in a similar manner to a conventional mechanical sun visor in its folded-down state.

[0056] The intermediate layer in the central field of view of the windshield is clear and transparent. This ensures unrestricted visibility through the central field of view, thus allowing the glass panel to be used as a windshield. A transparent thermoplastic intermediate layer is understood to be a layer having at least 70%, preferably at least 80%, of light transmittance in the visible spectrum. The transparent intermediate layer is present at least in the A field of view according to ECE-R43, and preferably also in the B field of view.

[0057] The windshield panel is preferably installed in a motor vehicle, and particularly preferably in a passenger-carrying motor vehicle.

[0058] In one possible implementation, the region of the thermoplastic interlayer used to bond the functional element to the outer or inner glass pane is tinted or colored. Therefore, this region has reduced transmittance in the visible spectrum compared to a non-tinted or uncolored layer. The tinted / colored region of the thermoplastic interlayer thus reduces the transmittance of the windshield in the sun visor region. In particular, the aesthetic impression of the functional element is improved because the tinting results in a more neutral appearance, which is more comfortable for the observer.

[0059] In another preferred embodiment of the composite glass panel according to the invention, it is used as a roof glass panel of a motor vehicle. The roof glass panel includes a front top edge adjacent to the windshield of the vehicle and a rear top edge pointing towards the rear glass panel, as well as two side edges extending along the vehicle doors between the front and rear top edges. Functional elements are designed to provide large-area sunshades for the roof glass panel, wherein the functional elements are arranged over at least 80%, preferably at least 90%, of the entire transparent area of ​​the roof glass panel, for example, 100% of the entire transparent area.

[0060] Busbars located on the edges of composite glass panels used as roof or windshield panels are covered with opaque overprinting typically used in the edge areas of the glass panel. If a functional element is used as a sun visor in a windshield panel, the edges of the functional element adjacent to the transparent area of ​​the windshield panel are typically left uncovered with overprinting.

[0061] In a preferred embodiment, the functional element, more precisely, its side edges, is surrounded by a thermoplastic frame film. The frame film is designed as a frame with grooves into which the functional element is inserted. The thermoplastic frame film can be formed from a thermoplastic film in which the grooves have been introduced by cutting. Alternatively, the thermoplastic frame film can also consist of multiple film segments surrounding the functional element. In a preferred embodiment, the intermediate layer is thus formed of at least three thermoplastic bonding films stacked facet to face, wherein the frame film, as the intermediate layer, has grooves in which the functional element is disposed. During manufacturing, the thermoplastic frame film is disposed between the first and second thermoplastic bonding films, wherein the side edges of all the thermoplastic films are preferably overlapped. The thermoplastic frame film preferably has approximately the same thickness as the functional element. This compensates for local thickness differences in the composite glass sheet introduced by the locally confined functional element, thereby preventing glass breakage during lamination. If the functional element is incorporated into a large area of ​​the composite glass sheet, the frame film can be omitted.

[0062] The side edges of the functional elements, visible when viewed through the composite glass panel, are preferably arranged flush with the thermoplastic frame film, so that there is no gap between the side edges of the functional elements and the corresponding side edges of the thermoplastic frame film. This is particularly suitable for the lower edges of functional elements serving as sun visors in windshields, where these edges are typically visible. Therefore, the boundary between the thermoplastic frame film and the functional elements is less visually noticeable.

[0063] Automotive glass, particularly windshields, rear windows, and roof windows, typically has a surrounding enamel printing layer, specifically designed to protect the adhesives used to mount the glass from UV radiation and visually conceal them. This enamel printing layer also preferably covers the edges of functional elements located in the edge areas of the assembled glass. Busbars and necessary electrical connections are also located in the area covered by this printing layer. In this way, the functional elements are advantageously integrated into the appearance of the composite glass panel. Preferably, at least the glass panel used as the outer glass panel has such a printing layer; particularly preferably, both the first and second glass panels (inner and outer glass panels) are printed with this printing layer to prevent visibility from both sides.

[0064] Functional elements may also have recesses or holes, for example, in areas known as sensor windows or camera windows. These areas are configured to house sensors or cameras whose functions are influenced by adjustable functional elements in the beam path, such as rain sensors.

[0065] The functional elements are preferably arranged across the entire width of the composite glass panel, minus the width of the edge regions on both sides, for example, 2 mm to 20 mm. The functional elements also preferably have a distance of, for example, 2 mm to 20 mm from the upper edge. The functional elements are thus encapsulated within an intermediate layer and protected from contact with the surrounding atmosphere and from corrosion.

[0066] The first thermoplastic bonding film, the second thermoplastic bonding film, and the optional thermoplastic frame film preferably contain at least polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), and / or polyurethane (PU), with PVB being particularly preferred.

[0067] The thickness of each thermoplastic bonding film and frame film is preferably 0.2 mm to 2 mm, particularly preferably 0.3 mm to 1 mm, especially 0.3 mm to 0.5 mm, for example 0.38 mm.

[0068] The first and second glass panes are preferably made of glass, particularly soda-lime glass, as is common for window panes. However, these glass panes may 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 glass panes may be clear, tinted, or colored. If the composite glass pane is used as a windshield, it should have sufficient light transmittance in the central viewing area, preferably at least 70% in the primary perspective area A according to ECE-R43.

[0069] The first glass plate, the second glass plate, and / or the intermediate layer may have other suitable coatings known per se, such as anti-reflective coatings, anti-stick coatings, anti-scratch coatings, photocatalytic coatings, sun-protective coatings, or low-emissivity coatings.

[0070] The thicknesses of the first and second glass plates can vary widely to suit various requirements. The first and second glass plates preferably have a thickness of 0.5 mm to 5 mm, and particularly preferably 1 mm to 3 mm.

[0071] The invention also includes a method for switching a functional element according to the invention, wherein a first voltage U1 is applied at least between a first segment of a first bus and a first segment of a second bus. The first voltage U1 corresponds to the switching voltage of the functional element, i.e., the voltage at which the functional element is fully switched to an active state. A full switch to an active state is identified as no further change in the optical performance of the functional element upon further increasing the applied voltage. A second voltage U2, less than the value of voltage U1, is applied between a second segment of the first bus and a second segment of the second bus. Therefore, in the second region of the functional element allocated to the second segment of the first bus and the second segment of the second bus, there is no full switch to an active state. Conversely, in the first region of the functional element allocated to the first segment of the first bus and the first segment of the second bus, there is a full switch to an active state. The first region in the active state is thus adjacent to the second region in the partially active state, so that the optically controllable performance of the functional element forms a more visually appealing distribution.

[0072] Preferably, the third region of the functional element is adjacent to the second region of the second segment of the first bus and the second segment of the second bus, and the third region is in contact with the third segment of the first bus and the third segment of the second bus. When no voltage is applied to the third region, the second region in the partially activated state forms a visually appealing transition between the fully activated first region and the inactive third region.

[0073] In a preferred embodiment of the method, the second voltage U2 is increased to the value of the first voltage U1 after a period of time that can be defined in a variable manner, thereby also fully activating the second region. Particularly preferably, a third voltage U3, less than the value of voltage U1, is then applied between the third section of the first bus and the third section of the second bus, or simultaneously. In the third region of the functional element to which voltage U3 is applied, a partial switching process of the functional element also occurs. To an observer of the functional element, the switching process appears as a wave-like expansion of the active region of the functional element.

[0074] The method according to the invention for switching functional elements according to the invention particularly preferably includes the following steps:

[0075] a) Apply a first voltage U1 corresponding to the switching voltage of the functional element between the nth segment of the first bus and the nth segment of the second bus.

[0076] b) Apply a second voltage U2 between the (n+1)th segment of the first bus and the (n+1)th segment of the second bus.

[0077] c) Increase the voltage between the (n+1)th segment of the first bus and the (n+1)th segment of the second bus to the value of the first voltage U1.

[0078] d) Apply a second voltage U2 between the (n+2)th segment of the first bus and the (n+2)th segment of the second bus.

[0079] e) Repeat steps c) and d) until a first voltage U1 exists between all sections of the first bus and the relevant sections of the second bus.

[0080] The nth and (n+1)th segments of the bus can be adjacent to each other or not adjacent. If the functional element includes more than one first bus and / or more than one second bus, the nth and (n+1)th segments of the bus can also be located on different side edges of the functional element. In this way, the functional element can be switched gradually according to the arrangement of these segments and the order in which they are controlled, wherein a gradient can optionally be maintained or the functional element can be gradually switched from an inactive state to an active state.

[0081] Specifically, the second voltage U2 is 10% to 80% of the first voltage U1, preferably 20% to 50% of the first voltage U1. Within this range, partial switching of the active layer is particularly advantageous. On the one hand, the change in optical performance is clearly visible and easily distinguishable from the inactive region of the functional element; on the other hand, it is significantly weaker than in the fully activated region of the functional element.

[0082] Voltage can be applied to the regions of the functional elements and the voltage distribution monitored accordingly using a control unit known to those skilled in the art. Overcharging or discharging of the functional elements should be prevented to avoid long-term damage to the active layer. To prevent this, the voltage is preferably not applied constantly, but rather the state of each region is monitored by measuring the open-circuit voltage between the busbar sections of the respective regions. The open-circuit voltage should be kept approximately constant.

[0083] The invention will be explained in more detail with reference to the accompanying drawings and embodiments. The drawings are schematic and not to scale. The drawings do not limit the invention in any way. They show:

[0084] Figure 1a -e Different views of the functional elements according to the present invention,

[0085] Figures 2a-2b Composite glass plates including functional elements according to the present invention,

[0086] Figures 3a-3b according to Figures 2a-2b The functional elements of the composite glass plate according to the present invention, and

[0087] Figures 4a-4c A schematic diagram of the switching process of the composite glass plate according to the present invention.

[0088] Figures 1a to 1e A functional element 5 according to the invention is shown, comprising four side edges 4.1, 4.2, 4.3, and 4.4. The functional element 5 is a multilayer film with electro-controllable optical properties, consisting of an active layer 11 between two planar electrodes 12 and 13 and two carrier films 14 and 15. The active layer 11 is an electrochromic layer whose color changes depending on the voltage applied to the planar electrodes, thereby allowing adjustment of the optical properties. The carrier films 14 and 15 are composed of PET and have a thickness of, for example, 0.125 mm. The carrier films 14 and 15 are equipped with an ITO coating of approximately 100 nm thickness, facing the active layer 11 and forming the first planar electrode 12 and the second planar electrode 13. The planar electrodes 12 and 13 can be connected to an onboard electrical system via busbars 18 and 19 and connecting cables (not shown). Busbars 18 and 19 are divided into segments 18.n and 19.n by separator lines 16, and these segments can be individually controlled via connecting cables. Figure 1aA top view of the first carrier film 14 of the functional element 5 is shown. A first groove 10.1 is introduced into the first carrier film 14 along the side edges 4.1, 4.2, 4.3, and 4.4 of the functional element 5, wherein the first carrier film 14 and the first planar electrode 12 located thereon are removed in the region of the first groove 10.1. The active layer 11 is also removed in this region to expose the second planar electrode 13. A second busbar 19 is disposed circumferentially on the surface of the first carrier film 14 opposite to the first planar electrode 12 along the side edges 4.1, 4.2, 4.3, and 4.4, wherein the second busbar passes through the region of the first groove 10.1 and makes conductive contact with the second planar electrode 13. Figure 1b It shows according to Figure 1a A top view of the second carrier film 15 of functional element 5. The second carrier film 15 has a second groove 10.2 surrounding the second carrier film 15 along the side edges 4.1, 4.2, 4.3, 4.4, which is alternately arranged with the first groove 10.1 of the first carrier film 14. Along the side edges 4.1, 4.2, 4.3, 4.4, a first busbar 18 is disposed surrounding the second carrier film 15 on the surface opposite to the second planar electrode 13, which passes through the region of the second groove 10.2 and makes conductive contact with the first planar electrode 12. Figure 1c It shows along according to Figure 1a The cross-section of the functional membrane 5 with cutting line AA', and Figure 1d It shows along Figure 1a The cross section of the cutting line BB'. Figure 1e A view of the functional membrane 5 is shown in the top view at side edge 4.3. The functional element 5 is surrounded by a first busbar 18 and a second busbar 19, thereby enabling a particularly uniform switching process for the functional element 5.

[0089] Figure 2a and 2b An embodiment of the composite glass plate 20 according to the present invention as a top glass plate is shown, wherein... Figure 2a A top view is shown. Figure 2b It shows along Figure 2aThe cross-section of the cutting line CC'. The top glass panel includes a first glass panel 1 serving as the outer glass panel and a second glass panel 2 serving as the inner glass panel. Here, the inner glass panel faces the interior space of the vehicle, while the outer glass panel faces the vehicle environment. The first glass panel 1 and the second glass panel 2 are joined together by an intermediate layer 3. The first glass panel 1 is composed of clear soda-lime glass with a thickness of 2.1 mm. The second glass panel 2 is composed of soda-lime glass with a thickness of 1.6 mm and is gray-tinted. The tinted inner glass contributes to the attractive appearance of the glass panel, as well as to the vehicle occupants when viewing through the top glass panel. The composite glass panel serving as the top glass panel has a front top edge D facing the windshield panel in the installation position and a rear top glass panel D' facing the rear glass panel in the installation position.

[0090] The top glass panel is equipped with a functional element 5 serving as a large-area sunshade, wherein the functional element 5 is an electrochromic functional element embedded in the intermediate layer 3. The intermediate layer 3 comprises a total of three thermoplastic bonding films 6, 7, and 8, each formed from a 0.38 mm thick PVB thermoplastic film. The first thermoplastic bonding film 6 is bonded to the first glass panel 1, and the second thermoplastic bonding film 7 is bonded to the second glass panel 2. An intermediate thermoplastic frame film 8 has cutouts into which the functional element 5 is precisely fitted, i.e., flush with all sides. The third thermoplastic layer thus appears to form a frame for the functional element 5, which is thus enclosed in and protected by the thermoplastic material on all sides. The thermoplastic bonding films 6, 7, and 8 are optionally colored, wherein one or more of these films may be completely or partially colored. Depending on the thickness of the functional element 5 and the resulting thickness difference with areas without the functional element 5, the frame film 8 may be omitted. This also depends on the complexity of the glass panel curvature of the composite glass panel. It can usually be found that when the thickness difference between the regions with functional elements and the regions without functional elements is small, and when the complexity of bending is low, the frame membrane can be omitted.

[0091] Optionally, an additional thermoplastic bonding film (not shown) may be introduced adjacent to the outer glass panel (first glass panel 1). For example, a carrier film with a functional layer, such as a carrier film with an infrared reflective coating, may be incorporated through the additional thermoplastic bonding film. The infrared reflective coating is oriented toward the first glass panel 1 (outer glass panel) and serves to reduce heating of the occupant interior space due to solar radiation.

[0092] The top glass panel has a surrounding cover 9 that covers both the adhesive bonding between the composite glass panel and the vehicle body and the electrical contact of the planar electrodes of the functional element 5. The surrounding peripheral cover 9 is formed of opaque enamel on the inner surfaces of the first glass panel 1 and the second glass panel 2 (facing the interior space of the vehicle in the mounting position). The distance between the functional element 5 and the front top edge D, the rear top edge D', and the side edges of the top glass panel is less than the width of the cover 9, such that the side edges 4.1, 4.2, 4.3, and 4.4 of the functional element 5 are covered by the cover 9. Here, the electrical connectors are also suitably located in the area of ​​the cover 9 and are thus advantageously covered.

[0093] For the thermoplastic bonding films 6, 7 and the thermoplastic frame film 8, so-called "high-flow PVB" is preferably used, which has stronger flow behavior compared to standard PVB films. Therefore, these layers flow more strongly around the functional element 5, resulting in a more uniform visual impression and a less noticeable transition from the functional element 5 to the frame film 8. "High-flow PVB" can be used for all or just one or more of the thermoplastic films 6, 7, 8 that are in direct contact with the functional element 5.

[0094] Figure 3a and 3b The diagram shows the process prior to the integration of functional element 5 into the composite glass plate 20. Figure 2a and 2b The functional element 5 of the composite glass plate 20 is also visible, and the electrical contact between the functional element 5 and the busbars 18 and 19 is also visible. Figure 3a The image shows a top view of functional element 5 on the first carrier membrane 14, while Figure 3b A top view of the second carrier membrane 15 is shown. Functional element 5 substantially corresponds to... Figures 1a-1eUnlike the description in [the original text], at least in the first planar electrode 12, dividing lines are introduced. Two of these dividing lines 16 extend coherently between the first side edge 4.1 and the fourth side edge 4.4, which are opposite each other, and divide the first planar electrode 12 into regions 17 that can be switched independently of each other. The first planar electrode 12 has dividing lines 16, for example, each with a width of 200 μm, which are introduced by laser method. The dividing lines 16 electrically isolate the regions 17 from each other. The number of regions 17 can be freely selected according to the application or customer requirements. Preferably, in order to divide the regions 17, dividing lines 16 are introduced into the first planar electrode 12, the second planar electrode 14, and the active layer 11. The first bus 18 and the second bus 19 are divided into segments 18.n of the first bus 18 and segments 19.n of the second bus 19 by dividing lines 16. Here, in order to divide the second bus 19, dividing lines 16 are introduced into the bus 19 between adjacent first grooves 10.1, respectively. Between adjacent second recesses 10.2, dividing lines 16 are introduced into the first busbars 18. Within each recess 10, there are therefore independently electrically controllable segments 18.n and 19.n of the busbars 18 and 19. Thus, within region 17, each sub-region can be independently controlled, with clear boundaries between these regions 17 and a smooth distribution between active and inactive regions of the functional elements within these regions.

[0095] Figure 4a , 4b Figures 4c and 4c respectively show exemplary schematic diagrams of the switching process of functional element 5, wherein region 17 is switched successively from an inactive state to an active state by applying voltage to the corresponding section of the bus. Figure 4a and 4b This illustrates the smooth distribution of controllable optical properties between adjacent regions 17. According to Figure 4c Dividing lines 16 are placed between regions 17 to make the clear separation of these regions visible.

[0096] List of reference numerals in the attached diagram:

[0097] 1 First glass plate

[0098] 2 Second glass plate

[0099] 3. Intermediate layer

[0100] 4.1, 4.2, 4.3, 4.4 Side edges of functional elements

[0101] 5. Functional components with electro-controllable optical properties

[0102] 6 First thermoplastic bonding film

[0103] 7 Second thermoplastic bonding film

[0104] 8. Thermoplastic frame membrane

[0105] 9. Covering printed materials

[0106] 10 Grooves

[0107] 10.1 First Groove

[0108] 10.2 Second Groove

[0109] 11. Active layer of functional element 5

[0110] 12. First planar electrode of functional element 5

[0111] 13. Second planar electrode of functional element 5

[0112] 14 First carrier membrane

[0113] 15 Second carrier membrane

[0114] 16 Separator lines

[0115] 17 regions

[0116] 18 First busbar

[0117] 19 Second busbar

[0118] 20 Composite Glass Panel

[0119] D. Front top edge of the composite glass panel

[0120] D' Composite Glass Panel Rear Top Edge

[0121] The side edge of the S-shaped composite glass panel

[0122] AA', BB', CC' are cutting lines.

Claims

1. A functional element (5) having multiple side edges (4.1, 4.2, 4.3, 4.4) and controllable optical properties, comprising at least a first carrier film (14) having a first planar electrode (12) and a second carrier film (15) having a second planar electrode (13), and an active layer (11) arranged in a planar form between the first planar electrode (12) and the second planar electrode (13), wherein - The first busbar (18) and the second busbar (19) are arranged on at least one first side edge (4.1), - The first carrier membrane (14) has at least one first groove (10.1) and the second carrier membrane (15) has at least one second groove (10.2), and in - A first busbar (18) is disposed on the surface of the second carrier film (15) opposite to the second planar electrode (13), and passes through it in the region of the at least one second groove (10.2), and makes conductive contact with the first planar electrode (12). - A second busbar (19) is disposed on the surface of the first carrier film (14) opposite to the first planar electrode (12), passes through the region of the at least one first groove (10.1), and makes conductive contact with the second planar electrode (13). - The at least one first busbar (18) is divided into at least one first segment (18.1) and at least one second segment (18.2) that can be controlled independently of each other, and / or the at least one second busbar (19) is divided into at least one first segment (19.1) and at least one second segment (19.2) that can be controlled independently of each other, and - The first groove (10.1) and the second groove (10.2) are arranged alternately.

2. The functional element (5) according to claim 1, wherein at least one additional first bus (18) and / or second bus (19) is arranged on at least the second side edge (4.2) of the functional element (5).

3. The functional element (5) according to claim 1 or 2, wherein a first busbar (18) and a second busbar (19) are respectively arranged on the first side edge (4.1), the second side edge (4.2), the third side edge (4.3) and the fourth side edge (4.4).

4. The functional element (5) according to any one of claims 1 to 2, wherein the first planar electrode (12) and / or the second planar electrode (13) includes at least one dividing line (16) that divides the functional element (5) into regions (17) that can be switched independently of each other.

5. The functional element (5) according to any one of claims 1 to 2, wherein the active layer (11) is an electrochromic layer.

6. The functional element (5) according to any one of claims 1 to 2, wherein the first bus (18) and the second bus (19) comprise conductive structures and have a thickness of 5 μm to 40 μm.

7. The functional element (5) according to claim 6, wherein the conductive structure comprises silver.

8. The functional element (5) according to any one of claims 1 to 2, wherein the first planar electrode (12) and the second planar electrode (13) comprise at least one metal, metal alloy or transparent conductive oxide, and have a thickness of 10 nm to 2 μm.

9. The functional element (5) according to claim 8, wherein the first planar electrode (12) and the second planar electrode (13) comprise a transparent conductive oxide.

10. A composite glass plate (20) comprising at least a functional element (5) according to any one of claims 1 to 9, a thermoplastic interlayer (3), a first glass plate (1) and a second glass plate (2), wherein the thermoplastic interlayer (3) has a first thermoplastic bonding film (6) disposed between the functional element (5) and the first glass plate (1) and a second thermoplastic bonding film (7) disposed between the functional element (5) and the second glass plate (2).

11. A method for switching a functional element (5) according to any one of claims 1 to 9, wherein a first voltage U1 corresponding to the switching voltage of the functional element (5) is applied at least between a first section (18.1) of the first bus (18) and a first section (19.1) of the second bus (19), and a second voltage U2, the value of which is less than the value of voltage U1, is applied between a second section (18.2) of the first bus (18) and a second section (19.2) of the second bus (19).

12. The method of claim 11, wherein the second voltage U2 is increased to the value of the first voltage U1.

13. The method according to claim 12, wherein a third voltage U3, which is less than the value of voltage U1, is applied between the third section (18.3) of the first bus (18) and the third section (19.3) of the second bus (19).

14. The method according to any one of claims 11 to 12, wherein a) Apply a first voltage U1 corresponding to the switching voltage of the functional element (5) between the nth segment (18.n) of the first bus (18) and the nth segment (19.n) of the second bus (19). b) Apply a second voltage U2 between the (n+1)th segment (18.n+1) of the first bus (18) and the (n+1)th segment (19.n+1) of the second bus (19). c) Increase the voltage between the (n+1)th segment (18.n+1) of the first bus (18) and the (n+1)th segment (19.n+1) of the second bus (19) to the value of the first voltage U1. d) Apply a second voltage U2 between the (n+2)th segment (18.n+2) of the first bus (18) and the (n+2)th segment (19.n+2) of the second bus (19). e) Repeat steps c) and d) until a first voltage U1 exists between all sections of the first bus (18) and the relevant sections of the second bus (19).

15. The method according to any one of claims 11 to 12, wherein the second voltage U2 is 10% to 80% of the first voltage U1.

16. The method of claim 15, wherein the second voltage U2 is 20% to 50% of the first voltage U1.

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