EP3697636A1

EP3697636A1 - Functional element having electrically controllable optical properties

Info

Publication number: EP3697636A1
Application number: EP18785646.3A
Authority: EP
Inventors: Marcel Klein; Alicia DRÖGE
Original assignee: Saint Gobain Glass France SAS; Compagnie de Saint Gobain SA
Current assignee: Saint Gobain Glass France SAS; Compagnie de Saint Gobain SA
Priority date: 2017-10-20
Filing date: 2018-10-18
Publication date: 2020-08-26
Also published as: CN109952220A; KR20200088322A; RU2752154C1; JP2020537604A; CA3079502A1; US20210189792A1; WO2019077014A1; MX2020004069A; BR112020007382A2; MA50389A

Abstract

The invention relates to a composite pane (100) having a functional element (5) having electrically controllable optical properties, comprising: a layer sequence of an outer pane (1), a first intermediate layer (3a), a second intermediate layer (3b) and an inner pane (2), the intermediate layers (3a, 3b) containing at least one thermoplastic polymer film having at least one plasticizer, a functional element (5) having electrically controllable optical properties being arranged at least in some regions between the first intermediate layer (3a) and the second intermediate layer (3b) and the functional element (5) being a polymer dispersed liquid crystal (PDLC) functional element and comprising a second layer sequence of at least a first carrier film (15), an active layer (11), and a second carrier film (14), at least one exit surface (8) of the active layer (11) on at least one lateral surface (5.1, 5.2, 5.3, 5.4) of the functional element (5) being sealed, at least in some sections, by means of at least one barrier layer (4), the barrier layer (4) being designed in such a way that the diffusion of plasticizer through the barrier layer (4) is largely prevented, and the barrier layer (4) being produced by a vacuum-based thin-film deposition method.

Description

Functional element with electrically controllable optical properties

The invention relates to a functional element with electrically controllable optical properties, a composite pane with functional element and in particular a windshield or a roof window of a vehicle with electrically controllable sun visor and a method for the production.

In the vehicle sector and in the construction sector, composite panels with electrically controllable functional elements are often used for sun protection or for visual protection. For example, windshields are known in which a sun visor is integrated in the form of a functional element with electrically controllable optical properties. In particular, the transmission or the scattering behavior of electromagnetic radiation in the visible range is electrically controllable. The functional elements are usually film-like and are laminated or glued to a composite pane. In the case of windshields, for example, the driver can control the transmission behavior of the pane itself with respect to solar radiation. So can be dispensed with a conventional mechanical sun visor. As a result, the weight of the vehicle can be reduced and space is gained in the roof area. In addition, the electric control of the sun visor for the driver is more comfortable than the manual folding down the mechanical sun visor.

Windshields with such electrically controllable sun visors are known, for example, from DE 102013001334 A1, DE 102005049081 B3, DE 102005007427 A1 and DE 102007027296 A1.

Typical electrically controllable functional elements include electrochromic layer structures or single particle device (SPD) films. Further possible functional elements for the realization of an electrically controllable sunscreen are so-called PDLC functional elements (polymer dispersed liquid crystal). Their active layer contains liquid crystals which are incorporated in a polymer matrix. When no voltage is applied, the liquid crystals are disordered, resulting in a strong scattering of light passing through the active layer. If a voltage is applied to the surface electrodes, the liquid crystals align in a common direction and the transmission of light through the active layer is increased. The PDLC function element works less by reducing the overall transmission, but by Increase the dispersion to ensure glare protection. PDLC functional elements are known, for example, from US 20150301367 A1.

Conventional, laminated-in functional elements and in particular PDLC functional elements often show undesirable signs of aging, such as whitening and changes in shading, in the edge area.

JP 2008225399 discloses a liquid crystal display element on a flexible substrate, such as a plastic film, wherein the side surfaces have a gas barrier layer which prevents gas from penetrating over a side surface of the substrate.

The present invention is therefore based on the object to provide an improved functional element with electrically controllable optical properties, which is improved in particular with regard to its aging resistance. The object of the present invention is achieved by a functional element according to independent claim 1. Preferred embodiments will become apparent from the dependent claims.

A functional element according to the invention with electrically controllable optical properties comprises at least one (second) stacking sequence of at least one first carrier foil, an active layer and a second carrier foil, wherein at least one exit surface of the active layer is sealed to at least one side surface of the functional element at least in sections with at least one barrier layer , The stacking sequence according to the invention preferably comprises at least: a first carrier foil, a first area electrode, an active layer, a second area electrode and a second carrier foil, which are arranged one above the other in this order. The stacking sequence is, for example, a prefabricated film which has a suitable size and shape. Inventive stacking sequences of films typically have a large area but only a small total thickness. Hereinafter, the large areas of the stacking sequence will be referred to as the area of the top surface and the bottom surface, and the orthogonal surfaces having only a small width (corresponding to the direction of the small total thickness) will be referred to as side surfaces. The active layer is bounded on both of its large surfaces by a respective carrier foil and optionally by a respective surface electrode. On the side surfaces of the stacking sequence of the first carrier foil, the first area electrode, the active layer, the second area electrode and the second carrier foil, the side surfaces of the carrier foils, the area electrodes and the active layer are respectively arranged. Since the active layer is covered at its large areas by surface electrodes and carrier foils, it is accessible only on the side surfaces of the stacking sequence of an external environment. The respective sections of the active layer on the side surfaces of the stacking sequence are referred to as exit surfaces of the active layer in the sense of the invention.

The invention is based on the knowledge of the inventors that an aging of an electrically controllable optical functional element substantially by penetration of harmful substances on the exit surface of the active layer or the exit surfaces of the surface electrodes in the interior of the functional element takes place and the optical properties of the functional element in an undesirable manner changed, for example, by a brightening or change in the transmission of the functional element, starting at its side edges. By sealing the functional element with a suitable barrier layer, the diffusion of harmful substances is inhibited or prevented in the functional element on its side surface. The above-mentioned aging phenomena are significantly reduced or completely prevented.

In an advantageous embodiment of a functional element according to the invention, the exit surfaces of the active layer on all side surfaces are completely sealed with the barrier layer. As a result, a particularly secure sealing of the active layer of the functional element and a particular good aging resistance of the functional element is achieved.

In a further advantageous embodiment of a functional element according to the invention at least one of the side surfaces are complete and preferably all side surfaces are completely sealed with the barrier layer. This achieves an even better sealing of the active layer of the functional element and an even better aging resistance of the functional element.

Sealed means in the sense of this invention that the corresponding portion of a surface is completely covered with the barrier layer as a protective layer and thus more resistant and is made more durable, in particular against the diffusion of harmful substances such as moisture, but in particular also against plasticizers from the environment, which penetrate into the interior of the functional element and in particular into the active layer. In a further advantageous embodiment of a functional element according to the invention all outer surfaces, that is in particular all side surfaces, the top and bottom are completely sealed with the barrier layer. This achieves an even better sealing of the active layer of the functional element and an even better aging resistance of the functional element. Furthermore, an even more homogeneous appearance of the functional element is achieved.

The barrier layer according to the invention is preferably in direct and direct contact with the functional element. For example, there is no separate adhesive or other intermediate layer between the barrier layer and the stacking sequence of the functional element.

The barrier layer according to the invention is preferably designed such that it prevents the diffusion of plasticizer through the barrier layer to the same extent or to a greater extent as the diffusion of plasticizer through the carrier films. The barrier layer according to the invention is preferably single-layered or multi-layered, for example two-layered, three-layered, four-layered or five-layered. The individual layers of the barrier layer will be referred to below as single layers and may consist of a same material or of different materials. The single layer or the individual layers of a multilayer barrier layer according to the invention preferably contain a transparent material. Transparent in the sense of the invention is a barrier layer which has a transmission in the visible spectral range of greater than 50%, preferably greater than 70% and in particular greater than 90%. For panes or disc sections that are not in the traffic-relevant field of view of the driver, for example, for roof windows or in the upper part of a windshield, or if a special darkening is desired, but the transmission can also be much less, for example, greater than 5%. In particular, the barrier layer may be tinted or colored. In an advantageous embodiment of the invention, the single layer or the individual layers are metal oxide-based, metal nitride-based or metal oxynitride-based, where the metal is preferably silicon (Si), aluminum (AI), tantalum (Ta) or vanadium (V) or a mixture it is.

The term "based" means in the context of the present invention that the material consists essentially of the metal oxide, metal nitride or metal oxynitride, preferably at least 80 wt .-%, more preferably at least 90 wt .-% and in particular at least 95 wt In the case of metal oxides, metal nitrides or metal oxynitrides, which are produced, in particular, by chemical vapor deposition, such as plasma-assisted vapor deposition, the term "based" encompasses, in addition to the metal oxides, metal nitrides or metal oxynitrides, even small amounts of residues of the process gases, such as Carbon and hydrogen as organic radicals of organometallic compounds.

Particularly preferred single layers are silicon oxide based, silicon nitride or silicon oxynitride based. In the case of silicon oxide-based individual layers, the silicon oxide SiO _{x is} preferably substoichiometric, particularly preferably 1 × 2 or stoichiometric (× = 2). But it can also be superstoichiometric.

In a particularly preferred embodiment, the barrier layer according to the invention contains or consists of at least one silicon oxide-based single layer. The silicon-based single layer may preferably contain low production-related amounts of carbon and hydrogen. Such a single layer preferably consists of SiO _x C _y : H with very low carbon and hydrogen content, where x is preferably from 0.1 to 3 and particularly preferably from 0.2 to 2, and y is preferably less than 0.2 and particularly preferably less than 0.1 and in particular less than 0.03.

Further preferred individual layers contain or consist of organometallic layers, preferably of organosilicon type SiO _x C _y : H, which are also referred to in the literature as SiO _x C _v H _z layer. Such layers are preferably formed by deposition from HMDSO and are then called plasma-polymerized HMDSO layers. Their stoichiometric composition depends on the deposition conditions, ie on the process parameters at the layer deposition. The organosilicon coating is preferably highly crosslinked. Without wishing to be bound by theory, such coatings may consist of a Network consisting of -Si-O-Si, -Si- (CH2) 2 -Si and -Si-O-Ch -Si units which terminate by Si-CH3, Si-CH2-CH3 and Si-H groups are.

In an advantageous embodiment of a barrier layer according to the invention, the barrier layer comprises or consists of at least one single layer of organosilicon of the SiO _x C _y : H type, where x is preferably from 0.1 to 3 and particularly preferably from 0.2 to 2, and y is preferred greater than 0.3, more preferably from 0.3 to 3, and especially from 0.9 to 2. The hydrogen content of the organosilicon compound depends on the degree of polymerization and the chemistry of the deposition processes. The ratio of carbon to hydrogen (C _U H _V ) can be arbitrary and is preferably from 1: 1000 to 1000: 1, particularly preferably from 1:10 to 10: 1. In an alternative barrier layer according to the invention, at least one single layer contains or consists of an organosilicon, the C _y H _z content of the organosilicon coating being from 20% by weight to 80% by weight, preferably from 30% by weight to 70% by weight .-% is. Such organosilicon coatings are preferably highly crosslinked and have a polymeric character.

Other preferred monolayers include or consist of amorphous hydrogenated carbon (aC: H), preferably amorphous hydrogenated nitrogen doped carbon (aC: N: H) or amorphous hydrogenated nitrogen and silicon doped carbon (aC: N: Si: H). These are preferably produced by CVD processes with acetylene (C2H2) or acetylene-containing process gases.

Other preferred monolayers include other vapor-deposited transparent ceramic layers and / or polymer layers that reduce or substantially prevent the diffusion of plasticizers, such as parylene, polyvinylidene chloride (PVDC), ethylene-vinyl alcohol copolymers (EVOP), or polyacrylates.

A particularly advantageous barrier layer according to the invention contains at least one single layer, with a material having a ceramic character. The single layer is preferably silicon oxide-based, silicon nitride-based, silicon oxynitride-based, aluminum oxide-based, tin oxide-based, zinc oxide-based, tin-zinc oxide-based or contains other mixed oxides. Preferably individual layers consist of silicon oxide, silicon nitride, silicon oxynitride, aluminum oxide, tin oxide, zinc oxide, tin-zinc oxide or other transparent mixed oxides or mixed nitrides. The metal oxide, metal nitride or metal oxynitride-containing layers may additionally be doped, for example with antimony, fluorine, silver, ruthenium, palladium, aluminum and tantalum.

In a particularly advantageous embodiment, the barrier layer contains at least two, preferably exactly two, exactly three, exactly four or exactly five superposed individual layers of the same material. This is particularly advantageous in the case of the thin individual layers used here, since defects in one of the individual layers can be compensated by the further individual layer (s).

In a particularly advantageous embodiment, the barrier layer contains exactly one or at least one two-layer layer, also called double layer or dyad. The double layer preferably consists of a first single layer with a polymeric character and a second single layer with a ceramic or inorganic character. In this case, the first individual layer is preferably arranged on the side of the double layer facing the functional element. The first single layer of a double layer is particularly preferably arranged directly on the functional element.

The first single layer preferably contains a polymer or polymerized material. Particular preference is given to the abovementioned organosilicon layers of the SiO _x C _y : H type having a high hydrocarbon content.

The second single layer is preferably metal oxide-based, metal nitride-based or metal oxynitride-based, wherein the metal is particularly preferably silicon. It preferably has only a small proportion of hydrocarbon and in particular has a ceramic character.

The invention is based in particular on the knowledge of the inventors that a combination of a first and a second single layer of the abovementioned materials is particularly advantageous with regard to the prevention of the diffusion of plasticizer from the intermediate layers into the active layer of the functional element. Without wishing to be bound by theory, the advantage of the double layers combined according to the invention is brought into connection with softener diffusion-inhibiting properties of the individual layers of ceramic or inorganic character in combination with adhesion-improving and defect-masking properties of the polymeric or polymer-like individual layers.

Particularly advantageous is a double layer or a sequence of several double layers, which consist of a first single layer of organosilicon (preferably with a large proportion of hydrocarbon). In this case, the first individual layer is preferably arranged on the side of the double layer or double layers facing the functional element. Here, the adhesion-improving and defect-masking properties of the first single layer and the softener-diffusion-inhibiting properties of the second single layer are particularly good. In the case of a series of multiple bilayers, it is particularly advantageous if the respective first individual layer (K for ceramic) and the second individual layer (P for polymerized) are arranged alternately one above the other, for two bilayers for example in the sequence (PK) - (PK) or in the sequence (KP) - (KP) or in the sequence (PK) - (KP) or in the sequence (KP) - (PK).

For three bilayers, for example, in the order (PK) - (PK) - (PK) or in the order (KP) - (KP) - (KP) or in the order (PK) - (KP) - (PK) or in any other permutation of (KP) and (PK). In an advantageous embodiment example, the barrier layer contains a first single layer of organosilicon with a large proportion of hydrocarbons and a second single layer which is silicon oxide-based and therefore has only a small proportion of hydrocarbon.

In an advantageous embodiment, one or more adhesion-improving layers can be arranged between functional element and barrier layer. In particular, the surface of the stacking sequence of the functional element can be subjected to an adhesion-improving surface treatment. Thus, the stacking sequence may be exposed to an argon (Ar) plasma, a nitrogen (N2) plasma or an oxygen (02) plasma for surface treatment. In an advantageous embodiment of a functional element according to the invention, the entire barrier layer of one or more individual layers over the exit surface of the active layer has a thickness d (also called material thickness) of 10 nm to 5000 nm (nanometers), preferably from 15 nm to 1000 nm and particularly preferred from 15 nm to 500 nm. The thickness d is determined orthogonal to the side surface above the exit surface of the active layer.

The thickness di, 2 of the individual layers over the exit surface of the active layer is preferably from 5 nm to 5000 nm (nanometers), preferably from 10 nm to 1000 nm and particularly preferably from 10 nm to 200 nm.

In an advantageous embodiment of a functional element according to the invention, the entire barrier layer comprising one or more individual layers over the side surface of the stacking sequence of the functional element has a thickness d (also called material thickness) of 10 nm to 5000 nm (nanometers), preferably 15 nm to 1000 nm and especially preferably from 15 nm to 500 nm. The thickness d is determined orthogonal to the side surface above the exit surface of the active layer.

Barrier layers according to the invention can be produced by any suitable deposition method. In this case, gas-phase deposition methods which enable the controlled production of particularly thin barrier layer thicknesses d are particularly suitable.

For the production of barrier layers according to the invention, the following deposition methods are particularly suitable:

o Physical vapor deposition (PVD), particularly preferred

Evaporate, like

o thermal evaporation,

o electron beam evaporation

o laser beam evaporation

o ion assisted deposition (IAD) or

o Arc evaporation

or

Sputtering (sputtering), how o magnetron sputtering

o atomic layer deposition, such as

Plasma Enhanced Atomic Layer Deposition (PEALD)

and or

o Chemical vapor deposition (CVD), particularly preferred

Plasma Enhanced Chemical Vapor Deposition (PECVD) Low Pressure Chemical Vapor Deposition (PECVD)

LPCVD)

• low temperature low pressure PECVD.

For functional elements with polymeric carrier films and temperature-sensitive active layers, the abovementioned plasma-assisted methods, such as PECVD and PEALD, are particularly suitable since they permit deposition at only low substrate temperatures.

A composite pane according to the invention comprises at least one (first) stacking sequence of an outer pane, a first intermediate layer, a second intermediate layer and an inner pane, wherein the intermediate layers contain at least one thermoplastic polymeric film with at least one plasticizer and at least in sections between the first intermediate layer and the second intermediate layer an inventive functional element is arranged with electrically controllable optical properties.

If the functional element is laminated into a composite pane, in particular the diffusion of plasticizers from the intermediate layers into the interior of the functional element on aging leads to brightening or alteration of the transmission, which impairs the transparency, functionality and aesthetics of the entire composite pane. By sealing the functional element with a suitable barrier layer, which inhibits or prevents the diffusion of plasticizers from the intermediate layer into the functional element and in particular into the side surface of the functional element, such aging phenomena are significantly reduced or completely prevented. The composite pane can be, for example, the windshield or the roof panel of a vehicle or another vehicle glazing, for example a separating disk in a vehicle, preferably in a rail vehicle or a bus. Alternatively, the composite pane may be architectural glazing, for example in an exterior facade of a building or a partition inside a building.

The terms outer pane and inner pane describe arbitrarily two different slices. In particular, the outer pane may be referred to as a first pane and the inner pane as a second pane.

If the composite pane is intended to separate an interior space from the outside environment in a window opening of a vehicle or a building, then the interior pane (vehicle interior) facing the pane (second pane) is referred to as interior pane in the sense of the invention. With outer pane, the outer environment facing disc (first disc) is called. The invention is not limited thereto.

The composite pane according to the invention contains a functional element according to the invention with electrically controllable optical properties, which is arranged at least in sections between a first intermediate layer and a second intermediate layer. The first and second intermediate layers usually have the same dimensions as the outer pane and the inner pane. The functional element is preferably foil-like.

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

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

Plasticizers are chemicals that make plastics softer, more flexible, smoother and / or more elastic. They shift the thermoelastic range of plastics towards lower temperatures, making the plastics in the range of Use temperature have the desired elastic properties. Further preferred plasticizers are carboxylic acid esters, especially low-volatility carboxylic acid esters, fats, oils, soft resins and camphor. Other plasticizers are preferably aliphatic diesters of tri- or tetraethylene glycol. Particularly preferred plasticizers used are 3G7, 3G8 or 4G7, where the first number denotes the number of ethylene glycol units and the last number denotes the number of carbon atoms in the carboxylic acid portion of the compound. So stands for 3G8 triethylene glycol bis (2- ethylhexanoate), ie a compound of formula C4H9CH (CH2CH3) CO (OCH ₂ CH ₂₎ 302CCH (CH2CH3) C4H9.

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

The thickness of each intermediate layer is preferably from 0.2 mm to 2 mm, particularly preferably from 0.3 mm to 1 mm, in particular from 0.3 mm to 0.8 mm, for example 0.76 mm. In an advantageous embodiment of a functional element according to the invention the barrier layer is designed such that it prevents the diffusion of plasticizers from the intermediate layer through the barrier layer.

In a particularly advantageous embodiment of a functional element according to the invention, the barrier layer is plasticizer-free, that is without targeted addition of a plasticizer.

The controllable functional element typically comprises a thin, active layer between two surface electrodes. The active layer has the controllable optical properties that can be controlled via the voltage applied to the surface electrodes.

In a composite pane according to the invention, the area electrodes and the active layer are typically arranged substantially parallel to the surfaces of the outer pane and the inner pane. The surface electrodes are electrically connected to an external voltage source in a manner known per se. The electrical contacting is realized by means of suitable connection cables, for example foil conductors, which are optionally connected to the surface electrodes via so-called bus bars, for example strips of an electrically conductive material or electrically conductive imprints.

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 may contain, for example, silver, gold, copper, nickel, chromium, tungsten, indium tin oxide (ITO), gallium-doped or aluminum-doped zinc oxide and / or fluorine-doped or antimony-doped tin oxide. The surface electrodes preferably have a thickness of 10 nm to 2 μηι, more preferably from 20 nm to 1 μηι, most preferably from 30 nm to 500 nm.

In addition to the active layer and the surface electrodes, the functional element may comprise further layers known per se, for example barrier layers, blocking layers, antireflection layers, protective layers and / or smoothing layers. The functional element is preferably present as 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. With outer carrier film is meant here that the carrier films form the two surfaces of the multilayer film. The functional element can thereby be provided as a laminated film, which can be advantageously processed. The functional element is advantageously protected by the carrier foils from damage, in particular corrosion. The multilayer film contains in the order given at least one carrier film, a surface electrode, an active layer, another surface electrode and another carrier film. In particular, the carrier foil carries the surface electrodes and gives the necessary mechanical stability to a liquid or soft active layer.

The carrier films preferably contain at least one thermoplastic polymer, particularly preferably low-plasticizer or plasticizer-free polyethylene terephthalate (PET). This is particularly advantageous with regard to the stability of the multilayer film. However, the carrier films may also contain other plasticizer-poor or plasticizer-free polymers or consist thereof, for example, ethylene vinyl acetate (EVA), polypropylene, polycarbonate, polymethyl methacrylate, polyacrylate, polyvinyl chloride, polyacetate resin, casting resins, acrylates, fluorinated ethylene-propylene, polyvinyl fluoride and / or ethylene-tetrafluoroethylene. The thickness of each carrier film is preferably from 0.02 mm to 1 mm, particularly preferably from 0.04 mm to 0.2 mm.

Typically, the carrier films each have an electrically conductive coating, which faces the active layer and acts as a surface electrode. The functional element according to the invention is preferably a PDLC functional element (polymer dispersed liquid crystal). The active layer of a PDLC functional element contains liquid crystals embedded in a polymer matrix. If no voltage is applied to the surface electrodes, the liquid crystals are aligned disorderly, resulting in a strong scattering of passing through the active layer light. If a voltage is applied to the surface electrodes, the liquid crystals align in a common direction and the transmission of light through the active layer is increased. Alternatively, functional elements and in particular PDLC functional elements may be used which are transparent when no voltage is applied (zero volts) and scatter strongly when a voltage is applied.

In principle, however, it is also possible to use other types of controllable functional elements, for example electrochromic functional elements or SPD functional elements (suspended particle device). The aforementioned controllable functional elements and their operation are known per se to those skilled in the art, so that a detailed description can be dispensed with at this point.

Functional elements as multilayer films are commercially available. The functional element is typically cut out of a multilayer film of larger dimensions in the desired shape and size. This can be done mechanically, for example with a knife. In an advantageous embodiment, the cutting is done by means of a laser. It has been found that the side surface is more stable in this case than in mechanical cutting. With mechanically cut side surfaces there may be the risk that the material retreats, which is visually striking and adversely affects the aesthetics of the disc. In a composite pane according to the invention, the functional element is connected to the outer pane via a region of the first intermediate layer and to the inner pane via a region of the second intermediate layer. The intermediate layers are preferably arranged flat on each other and laminated together, wherein the functional element between the two layers is inserted. The overlapping with the functional element areas of the intermediate layers then form the areas which connect the functional element with the discs. In other areas of the pane, where the intermediate layers are in direct contact with each other, they can fuse together during lamination in such a way that the two original layers may no longer be recognizable and instead a homogeneous intermediate layer is present.

An intermediate layer can be formed for example by a single thermoplastic film. An intermediate layer may also be formed as a two-layer, three-layer or multi-layer film stack, the individual films having the same or different properties. An intermediate layer can also be formed from sections of different thermoplastic films whose side surfaces adjoin one another.

In an advantageous development of a composite pane according to the invention, the area of the first or the second intermediate layer via which the functional element is connected to the outer pane or the inner pane is tinted or colored. The transmission of this region in the visible spectral range is thus reduced compared to a non-toned or colored layer. The tinted / colored area of the intermediate layer thus reduces the transmission of the windscreen in the region of the sun visor. In particular, the aesthetic impression of the functional element is improved because the tinting leads to a more neutral appearance, which is more pleasant to the viewer.

For the purposes of the invention, electrically controllable optical properties are to be understood as meaning those properties which are infinitely variable, but equally also those which can be switched between two or more discrete states.

The electrical control of the sun visor, for example, by means of switches, rotary or sliders, which are integrated in the fittings of the vehicle. But it can also be a button for controlling the sun visor integrated into the windshield, for example, a capacitive button. Alternatively or additionally, the sun visor can be controlled by non-contact methods, for example by detecting gestures, or depending on the state of the pupil or eyelid detected by a camera and suitable evaluation electronics. Alternatively or additionally, the sun visor can be controlled by sensors which detect a light incident on the pane.

The tinted or colored area of the intermediate layer preferably has a transmission in the visible spectral range of from 10% to 50%, particularly preferably from 20% to 40%. This achieves particularly good results with regard to glare protection and visual appearance.

The intermediate layer can be formed by a single thermoplastic film in which the tinted or colored area is produced by local tinting or dyeing. Such films are available, for example, by coextrusion. Alternatively, an untoned film portion and a tinted or colored film portion may be assembled to the thermoplastic layer.

The tinted or colored area can be homogeneously colored or tinted, that is to say have a location-independent transmission. The tinting or coloring can also be inhomogeneous, in particular, a transmission profile can be realized. In one embodiment, the transmittance in the tinted or colored area decreases at least in sections as the distance from the top edge increases. Thus, sharp edges of the tinted or colored area can be avoided, so that the transition from the sun visor to the transparent area of the windshield is gradual, which looks more aesthetically pleasing.

In an advantageous embodiment, the area of the first intermediate layer, ie the area between the functional element and the outer pane, is tinted. This causes a particularly aesthetic impression on top view of the outer pane. The region of the second intermediate layer between the functional element and the inner pane can optionally also be dyed or tinted.

The composite pane with electrically controllable functional element can be advantageously designed as a windscreen with electrically controllable sun visor. Such Windshield has an upper edge and a lower edge and two extending between the upper edge and lower edge side edges. With the upper edge that edge is referred to, which is intended to point in the installed position upwards. The lower edge is the edge which is intended to point downwards in the installed position. The upper edge is often referred to as the roof edge and the lower edge as the engine edge.

Windshields have a central field of view, on the optical quality of which are made high demands. The central field of view must have a high light transmission (typically greater than 70%). The said central field of view is in particular that field of view which is designated by the person skilled in the art as field of view B, field of view B or zone B. Field of View B and its technical requirements are set out in United Nations Economic Commission for Europe (UN / ECE) Control No 43 (ECE-R43, "Uniform Conditions for the Approval of Safety Glazing Materials and their Installation in Vehicles") Field of view B is defined in Annex 18.

The functional element is then advantageously arranged above the central field of vision (field of view B). This means that the functional element is arranged in the region between the central field of vision and the upper edge of the windshield. The functional element does not have to cover the entire area, but is completely positioned within this area and does not protrude into the central field of view. In other words, the functional element has a smaller distance to the upper edge of the windshield than the central viewing area. Thus, the transmission of the central field of view is not affected by the functional element, which is positioned in a similar position as a classic mechanical sun visor in the folded down state.

The windshield is preferably provided for a motor vehicle, particularly preferably for a passenger car. In a preferred embodiment, the functional element, more precisely the side surfaces of the functional element with the barrier layer circumferentially surrounded by a third intermediate layer. The third intermediate layer is formed like a frame 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 by cutting. Alternatively, the third intermediate layer may also consist of several Foil sections are assembled around the functional element. The intermediate layer is preferably formed from a total of at least three thermoplastic layers arranged on top of each other, wherein the middle layer identifies a recess in which the functional element is arranged. In the production, the third intermediate layer is arranged between the first and the second intermediate layer, wherein the side surfaces of all intermediate layers are preferably arranged in cover. The third intermediate layer preferably has approximately the same thickness as the functional element. Thereby, the local thickness difference of the windshield, which is introduced by the localized functional element, compensated, so that glass breakage during lamination can be avoided.

The visible in view through the windshield side surfaces of the functional element are preferably arranged flush with the third intermediate layer, so that there is no gap between the side surface of the functional element and the associated side surface of the intermediate layer. This is especially true for the lower surface of the functional element, which is typically visible. Thus, the boundary between the third intermediate layer and functional element is optically less noticeable.

In a preferred embodiment, the lower edges of the functional element and the tinted region of the intermediate layer (s) are adapted to the shape of the upper edge of the windshield, which causes a visually appealing appearance. Since the upper edge of a windshield is typically bent, in particular bent concavely, the lower edge of the functional element and of the tinted region is preferably bent. Particularly preferably, the lower edges of the functional element are formed substantially parallel to the upper edge of the windshield. But it is also possible to build the sun visor from two straight halves, which are arranged at an angle to each other and the shape of the upper edge are approximated v-shaped. In one embodiment of the invention, the functional element is divided into segments by insulation lines. The insulation lines are in particular incorporated in the surface electrodes, so that the segments of the surface electrode are electrically isolated from each other. The individual segments are independently connected to the voltage source, so that they can be controlled separately. This allows different areas of the sun visor to be switched independently. Particularly preferred are the Insulation lines and the segments arranged horizontally in the installation position. Thus, the height of the sun visor can be controlled by the user. As used herein, the term "horizontal" is to be broadly interpreted to mean a direction of propagation that extends between the side edges of the windshield of a windshield.The insulator lines may not necessarily be straight, but may also be slightly curved, preferably adapted to eventual bending of the top of the windshield Of course, vertical insulation lines are also conceivable.The insulation lines have, for example, a width of 5 μm to 500 μm, in particular 20 μm to 200 μm The width of the segments, that is to say the distance between adjacent insulation lines, can be from The insulation lines can be introduced by laser ablation, mechanical cutting or etching during the production of the functional element can still be segmented by means of laser ablation.

The upper edge and the adjacent side surface or all side surfaces of the functional element are preferably concealed by an opaque covering pressure or by an outer frame when viewed through the composite pane. Windshields typically have peripheral peripheral masking pressure from an opaque enamel, which is particularly useful for protecting and visually obscuring the adhesive used to install the windshield from UV radiation. This peripheral covering pressure is preferably used to conceal the upper edge and the side surface of the functional element, as well as the required 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 viewer. Preferably, both the outer pane and the inner pane have a covering pressure, so that the view is prevented from both sides.

The functional element can also have recesses or holes, for example in the area of so-called sensor windows or camera windows. These areas are intended to be equipped with sensors or cameras whose function would be affected by a controllable functional element in the beam path, for example Rain sensors. It is also possible to realize the sun visor with at least two separate functional elements, wherein there is a distance between the functional elements, which provides a space for sensor or camera windows. The functional element (or the entirety of the functional elements in the above-described case of a plurality of functional elements) is preferably arranged over the entire width of the composite pane or windshield, minus a double-sided edge region having a width of, for example, 2 mm to 20 mm. Also at the top, the functional element preferably has a spacing of, for example, 2 mm to 20 mm. The functional element is thus encapsulated within the intermediate layer and protected from contact with the surrounding atmosphere and corrosion.

The outer pane and the inner pane are preferably made of glass, more preferably of soda-lime glass, as is customary for window panes. However, the panes can also be made of other types of glass, for example quartz glass, borosilicate glass or alumino-sililate glass, or of rigid clear plastics, for example polycarbonate or polymethyl methacrylate. The panes can be clear or tinted or colored. Windscreens must have sufficient light transmission in the central viewing area, preferably at least 70% in the main viewing area A according to ECE-R43.

The outer pane, the inner pane and / or the intermediate layer may have further suitable coatings known per se, for example antireflective coatings, non-stick coatings, anti-scratch coatings, photocatalytic coatings or sunscreen coatings or low-E coatings).

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

The invention further comprises a method for producing a functional element according to the invention with electrically controllable optical properties, wherein at least a) a stacking sequence of at least one first carrier foil, an active layer and a second carrier foil is provided, and b) an exit surface of the active layer on at least one side surface of the functional element is at least partially and preferably completely sealed with a barrier layer by a vacuum-based thin-film deposition method. A stacking sequence of at least one first carrier foil, a first area electrode, an active layer, a second area electrode and a second carrier foil is preferably provided.

The stacking sequence is, for example, a prefabricated film which is brought to a suitable size and shape.

The vacuum-based thin-film deposition method according to the invention is preferably one of the following methods:

o Physical vapor deposition (PVD), particularly preferred

Evaporate, like

o thermal evaporation,

o electron beam evaporation

o laser beam evaporation

ion assisted deposition (IAD) or ion assisted deposition

o Arc evaporation

or

Sputtering (sputtering), how

o magnetron sputtering

Atomic Layer Deposition (PEALD), such as

• Plasma-assisted atomic layer deposition (plasma

Atomic Layer Deposition, PEALD)

or

o Chemical vapor deposition (CVD), particularly preferred

Plasma Enhanced Chemical Vapor Deposition (PECVD)

Low pressure chemical vapor deposition (LPCVD) • low temperature low pressure PECVD.

The barrier layers deposited by vacuum-based thin-film deposition processes preferably contain the abovementioned materials according to the invention and the abovementioned structure according to the invention.

A further aspect of the invention comprises a PDLC functional element (5) with electrically controllable optical properties, comprising

a stacking sequence of at least:

a first carrier film of PET,

a PDLC layer as the active layer and

a second carrier film of PET,

wherein at least the side surfaces of the functional element are sealed with at least one plasma-assisted vapor deposition (PECVD) barrier layer.

The barrier layer preferably contains at least one silicon oxide-based single layer, particularly preferably a double layer of an organosilicon-containing single layer (with a large hydrocarbon fraction) and a silicon oxide-based single layer (with a low hydrocarbon fraction).

In an advantageous development of the method according to the invention, the process gas used in the PECVD process is an organosilicon compound, preferably disiloxane, more preferably hexamethyldisiloxane (HMDSO), tetramethyldisiloxane (TMDSO) or tetraethoxysilane (TEOS). Such process gases are particularly well suited for the production of an organosilicon-containing single layer. Particularly suitable is the deposition with HMDSO as a process gas, since the deposition at low temperatures (usually 50 ° C to 100 ° C) can be carried out, and the deposition is also possible on temperature-sensitive surfaces such as plastics.

In an advantageous development of the method according to the invention, the first process gas used in the PECVD process is an organosilicon compound, preferably disiloxane, more preferably hexamethyldisiloxane (HMDSO) or tetramethyldisiloxane (TMDSO) and oxygen (O 2) used as the second process gas. Preferably, the oxygen is introduced under excess oxygen into the plasma, preferably with a ratio of HMDSO: C> 2 from 1: 2 to 1: 100, preferably 1: 5 to 1: 15 and more preferably from 1: 8 to 1: 12 and for example 1:10. Such process gas mixtures are particularly well suited for the production of silicon oxide-based individual layers with only minor hydrocarbon radicals.

Alternatively, amorphous hydrogenated carbon (a-C: H) barrier layers may be prepared alone or in combination with others, and more particularly with silica-based monolayers. The process gas used here is preferably acetylene. Alternatively, alone or in combination with others, and in particular silica-based monolayers, barrier layers of amorphous hydrogenated nitrogen-doped carbon (a-C: N: H) can be prepared. As the process gas, a mixture of acetylene and nitrogen is preferably used here. Alternatively, barrier layers of amorphous hydrogenated carbon doped with nitrogen and silicon (aC: N: Si: H) can be produced alone or in combination with other and in particular with silicon oxide-based individual layers become. The preferred process gas is a mixture of acetylene, nitrogen and HMDSO. In an advantageous development of the method according to the invention, the surface of the stacking sequence can be subjected to an adhesion-improving surface treatment before the deposition of the barrier layer or between the deposition of the individual layers. Thus, the stacking sequence or single layer may be exposed to an Ar plasma, a nitrogen (N 2) plasma or an oxygen (O 2) plasma for surface treatment.

In an advantageous development of the method according to the invention, the functional element is completely sealed on all outer surfaces with the barrier layer. For this example, the support surface of the functional element on a support or the contact surface of a holder during the coating or between two coating steps can be changed or, for example, the functional element can be rotated or turned.

Another aspect of the invention relates to a method for producing a composite pane according to the invention, wherein in a subsequent method step c) an outer pane, a first intermediate layer, the functional element according to the invention with electrically controllable optical properties, a second intermediate layer and an inner pane are arranged one above the other in this order, and

d) the outer pane and the inner pane are connected by lamination, wherein an intermediate layer with interposed functional element is formed from the first intermediate layer and the second intermediate layer.

In an advantageous development of the method according to the invention, a third intermediate layer is arranged in method step c) between the first intermediate layer and the second intermediate layer, which edges surround the functional element.

The electrical contacting of the surface electrodes of the functional element preferably takes place before the lamination of the composite pane. Any existing prints, such as opaque cover printing or printed bus bars for electrical contacting of the functional element are preferably applied by screen printing.

The lamination preferably takes place under the action of heat, vacuum and / or pressure. Lamination methods known per se can be used, for example autoclave methods, vacuum bag methods, vacuum ring methods, calendering methods, vacuum laminators or combinations thereof.

The invention further comprises the use of a composite pane according to the invention with an electrically controllable functional element as interior glazing or exterior glazing in a vehicle or a building, wherein the electrically controllable functional element is used as a sunscreen or as a privacy screen.

The invention further comprises the use of a functional element according to the invention in a windscreen or roof panel of a vehicle, wherein the functional element is used as a sun visor.

The invention further includes the use of a functional element according to the invention in an interior glazing or exterior glazing in a vehicle or a building, wherein the electrically controllable functional element is used as a sunscreen or as a screen.

The invention further comprises the use of a composite pane according to the invention as a windshield or roof panel of a vehicle, wherein the electrically controllable functional element is used as a sun visor.

A major advantage of the invention in composite windshield windshield is that can be dispensed with a classic mounted on the vehicle roof, mechanically folding sun visor. The invention therefore also encompasses a vehicle, preferably a motor vehicle, in particular a passenger car, which has no such conventional sun visor.

The invention also encompasses the use of a tinted or colored region of an intermediate layer for connecting a functional element with electrically controllable optical properties to an outer pane or inner pane of a windshield, wherein an electrically controllable sun visor is realized by the tinted or colored region of the intermediate layer and the functional element. The invention will be 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. Show it:

Figure 1A is a plan view of a first embodiment of an inventive

Composite pane with functional element according to the invention,

Figure 1 B is a cross section through the composite pane of Figure 1A along the section line

Χ-Χ '

FIG. 1C shows an enlarged representation of the region Z from FIG. 1B,

FIG. 1 D shows an enlarged representation of the region Z 'from FIG. 1 C,

FIG. 1E shows an enlarged representation of the region Z "from FIG. 1C,

FIG. 2 shows a schematic representation of a device for depositing a barrier layer according to the invention,

FIG. 3 shows a flow chart of an exemplary embodiment of the invention

process FIG. 4A shows a plan view of a further embodiment of a composite pane according to the invention using the example of a windscreen with a sun visor,

FIG. 4B shows a cross section through the composite pane from FIG. 4A along the section line

X-X '.

FIGS. 1A, 1B, 1C, 1D and 1E each show a detail of a composite pane 100 according to the invention. The composite pane 100 comprises an outer pane 1 and an inner pane 2, which are connected to one another via a first intermediate layer 3a and a second intermediate layer 3b. The outer pane 1 has a thickness of 2.1 mm and consists for example of a clear soda-lime glass. The inner pane 2 has a thickness of 1, 6 mm and, for example, also consists of a clear soda-lime glass. The composite disk 100 has a first edge designated D, which is referred to as upper edge in the following. The composite pane 100 has a second edge designated M, which is arranged opposite the upper edge D and is referred to below as the lower edge. The composite pane 100 can be arranged, for example, as architectural glazing in the frame of a window with additional panes for insulating glazing.

Between the first intermediate layer 3a and the second intermediate layer 3b, a functional element 5 according to the invention is arranged, which can be controlled by an electrical voltage in its optical properties. The electrical leads are not shown for simplicity.

The controllable functional element 5 is, for example, a PDLC multilayer film consisting of a stacking sequence with an active layer 11 between two surface electrodes 12, 13 and two carrier foils 14, 15. The active layer 11 contains a polymer matrix with liquid crystals dispersed therein Align the voltage applied to the surface electrodes voltage, whereby the optical properties can be controlled. The carrier films 14, 15 are made of polyethylene terephthalate (PET) and have a thickness of, for example, 0.125 mm. The carrier foils 14, 15 are provided with a coating of ITO having a thickness of approximately 100 nm facing the active layer 11, which form the area electrodes 12, 13. The surface electrodes 12, 13 are connectable via not shown bus bars (for example, formed by a silver-containing screen printing) and not shown connection cable with the on-board electrical system. The intermediate layers 3a, 3b each comprise a thermoplastic film having a thickness of 0.38 mm. The intermediate layers 3a, 3b consist for example of 78% by weight of polyvinyl butyral (PVB) and 20% by weight of triethylene glycol bis (2-ethylhexanoate) as plasticizer.

The functional element 5 has on all side surfaces 5.1, 5.2, 5.3, 5.4 a barrier layer 4, for example, the entire side surfaces 5.1, 5.2, 5.3, 5.4, the entire surface of the top (ie the first intermediate layer 3a facing surface) of the functional element. 5 and partially covers the surface of the underside (ie the surface facing the second intermediate layer 3b) of the functional element 5. Alternatively, the functional element 5 can be completely coated on its outer surfaces, for example by changing the holders or by turning the functional element during the coating or between two coating steps. The barrier layer 4 reduces or prevents diffusion of plasticizer into the active layer 11, which increases the service life of the functional element 5. The thickness (or in other words, the material thickness) d of the barrier material 4 over (i.e., orthogonal to) the exit surface 8 is, for example, at least 50 nm. Figures 1 D and 1 E show an embodiment in which the barrier layer 4 is double-layered. FIG. 1 D shows an enlarged region Z 'of the upper side of the functional element 5 from FIG. 1C and FIG. 1E the enlarged region of the lateral edge 5.1 of the functional element 5 with the exit surface 8 of the active layer 11 of FIG two-layer barrier layer 4 is arranged directly on the stacking sequence of the functional element 5. It consists of an organosilicon layer with a layer thickness di of, for example, 50 nm. The first individual layer 4.1 is on all side surfaces 5.1 -5.4 of the functional element 5, on the surface of the upper side (ie outside of the first carrier film 14) and partially on the surface of the underside (FIG. So arranged on the outside of the second carrier film 15).

The second individual layer 4.2 of the two-layer barrier layer 4 is arranged directly on the first individual layer 4.1. It is based on silicon oxide and has a layer thickness 2 of, for example, 100 nm. The total layer thickness d of the barrier layer 4 here is, for example, d = di + d2 = 150 nm. The individual layers 4.1, 4.2 are deposited on the stacking sequence of the functional element 5, for example, by the method described under FIG. 2 and FIG. Both the first individual layer 4.1 and the second individual layer 4.2 are so transparent and colorless that they do not impair the view through the functional element 5 and are completely invisible to the human eye.

Such composite disks 100 with inventive barrier layer 4 show in aging tests a significantly reduced brightening in the edge region of the functional element 5, since diffusion of the plasticizer from the intermediate layers 3a, 3b in the functional element 5 and a concomitant degradation of the functional element 5 is avoided. FIG. 2 shows an exemplary device for producing a functional element 5 according to the invention and for carrying out the method according to the invention by way of example.

The device comprises a vapor deposition unit 20 using the example of a PECVD system. For this purpose, a cathode 24 and an anode 25 are arranged in a vacuum chamber 21. By applying a high-frequency alternating field from a high-frequency generator 22 and a matching electronics 23 between the cathode 24 and anode 25, a plasma within a plasma zone 27 between cathode 24 and anode 25 is ignited. The vacuum is generated by a vacuum pump 28 connected to a gas outlet 31.

At the same time, at least one first process gas Gi is introduced through at least one first gas inlet 30. 1, the plasma zone 27. The cathode 24 is formed, for example, as a spray head cathode. Sprühkopfkathode means that the cathode 24 has a plurality of holes through which the first process gas Gi can flow. The cathode 24 is designed and connected to the first gas inlet 30.1 such that the first process gas Gi can flow through the cathode 24 over a wide area into the vacuum chamber 21 and in particular into the plasma zone 27. On the anode 25, a sample holder 26 is arranged. The sample holder 26 consists of, for example, a plate, a ring, a plurality of rings, a grid or other suitable shapes.

The stack of the functional element 5 to be coated with a barrier layer 4 is arranged on the sample holder 26. The sample holder 26 may be formed, for example, frame-shaped, flat or with multiple support points. In an advantageous embodiment of a sample holder 26 according to the invention, the sample holder is designed such that the functional element 5 protrudes on all sides by a projection U over the sample holder 26. This ensures that the entire side surfaces 5.1 -5.4 are coated on all sides with the barrier material 4. In particular PECVD methods show particularly good edge covering properties and therefore allow a particularly good coating of side surfaces 5.1 -5.4, which are arranged orthogonal to the anode 25.

If vapor-phase organic precursor compounds (precursor monomers) are introduced into the plasma zone 27 as the first process gas G1, these precursor compounds are first activated by the plasma. In addition to the radicals formed in this way, ions are also generated in a plasma which, together with the radicals, cause the layer deposition on the substrate. As a rule, the gas temperature in the plasma increases only slightly, as a result of which more temperature-sensitive materials can also be coated.

Depending on the process gas, activation may result in the formation of ionized molecules that form in the gas phase, for example, into molecular fragments in the form of clusters or chains. Subsequently, the molecular fragments condense on the substrate (here on the functional element 5). With a suitable choice of the process gas, the molecular fragments can polymerize under the influence of substrate temperature, electron and ion bombardment on the surface and form a closed layer.

Via a second gas inlet 30.2, a second process gas G2 can be introduced into the vacuum chamber 21. The second gas inlet 30.2 is formed, for example, as a ring shower. That is, the second gas inlet 30.2, for example, in such a ring around the plasma zone 27 is guided, that the second process gas G2 can flow laterally into the plasma zone 27 from all sides through openings in an annular tube.

It is understood that only the second process gas G2 can be introduced into the vacuum chamber 21, i. without the simultaneous introduction of the first process gas GL

For example, HMDSO or TMDSO can be used as the first process gas Gi, and, if appropriate, oxygen (O2), for example, can be used as the second process gas G2.

If a process gas Gi or G2 which is liquid at room temperature is used, then it can be converted into the gas phase by an evaporator unit (not shown here).

Figure 3 shows a schematic representation for carrying out the method according to the invention using the example of a PECVD method.

An exemplary embodiment of the method according to the invention for producing a functional element (5) according to the invention with electrically controllable optical properties comprises the following steps:

I.) a stack of at least

a first carrier foil (15),

- an active layer (1 1) and

a second carrier foil (14)

is provided and

II.) An exit surface (8) of the active layer (1 1) is at least partially sealed with at least one side surface (5.1, 5.2, 5.3, 5.4) of the functional element (5) with a barrier layer (4), wherein the barrier layer (4) with a PECVD method on the functional element (5) is deposited. The PECVD method is performed, for example, in a vacuum chamber 21 of the apparatus shown in FIG. The power is supplied for example by several magnetrons, for example, at 2.45 GHz, optionally operated in pulsed mode, are. The standard pressure of the PECVD chamber is for example about 5 ^* 10 ^"5 mbar. PECVD processes have the particular advantage that the substrates to be coated are only slightly heated, which is advantageous in particular in the case of temperature-sensitive PDLC films. In a preferred embodiment, a single layer 4.1 is deposited on the stacking sequence of the functional element 5 as a barrier layer 4. For the deposition, vaporized HMDSO is introduced via the gas inlet 30. 1 and the spray head cathode 21 into the plasma zone 27 as the first process gas d. In this case, for example, no second process gas G2 or only an inert process gas G2 such as argon is supplied.

The individual layer 4.1 then contains an organosilicon coating of the type SiO _x C _y : H. Their stoichiometric composition depends on the deposition conditions, ie on the process parameters at the layer deposition. The organosilicon coating is preferably highly crosslinked. The organosilicon coating consists for example of SiiOo, ₇ Ci, ₇ : H.

In a further preferred embodiment, an alternative single layer 4.1 is deposited on the stacking sequence of the functional element 5 as a barrier layer 4. For deposition, vaporized HMDSO is introduced via the gas inlet 30.1 and the spray head cathode 21 into the plasma zone 27 as the first process gas G1. At the same time, oxygen (O 2) is introduced via the second gas inlet 30. 2 and the annular shower into the plasma zone 27 as the second process gas G 2.

Advantageously, the first process gas G1 (HMDSO) is introduced in a ratio to the second process gas G2 (O2) of preferably Gi: G2 of 1: 5 to 1:20 and for example of 1:10.

By the reaction of the first process gas G1 of HMDSO with the second process gas G2 of oxygen, an SiO _x -based single layer 4.1 is deposited on the stacking sequence. That is, the individual layer 4.1 consists essentially of SiO _x , for example, x = 1, 9 applies and the single layer 4.1 also contains only small amounts of carbon and hydrogen as the organic radical of the organosilicon compound of the first process gas G1. The SiO _x -based individual layer 4.1 preferably contains more than 90% by weight. The respective layer thicknesses d of the barrier layer 4 and the compositions of the barrier layer 4 can be freely selected by a parameter selection familiar to the person skilled in the art, in particular by the deposition time, in the context of the method according to the invention.

In particular, multi-layer barrier layers 4 with different compositions can be deposited in addition to individual layers 4.1.

In a further preferred embodiment, a two-layer barrier layer 4 is deposited from two individual layers 4.1, 4.2, which is shown by way of example in FIGS. 1C and 1D.

For this purpose, first a first single layer 4.1 of, for example, SiiOo, 7Ci, 7: H is deposited on the stacking sequence. For this purpose, as described above, only a first process gas d from HMDSO is introduced into the plasma zone 27.

Subsequently, an SiO _x -based second individual layer 4.2 is deposited on the first individual layer 4.1. For this purpose, as described above, a first process gas d of HMDSO and a second process gas G2 of oxygen, for example in the ratio of 1:10, are introduced into the plasma zone 27.

In a further embodiment, the surface of the stacking sequence can be pretreated before the deposition of the barrier layer 4, for example, cleaned, etched or roughened. The stacking sequence can be exposed, for example, to a plasma without process gases or only with oxygen as a process gas. In this way, it is possible to improve the adhesion of the barrier layer 4 deposited thereon.

It is self-evident that other multilayer barrier layers 4 with different material compositions, material combinations and material permutations can also be deposited by the method according to the invention shown here. Thus, different process gases can be supplied to the PECVD system in a simple manner and thereby barrier layers with different materials can be deposited.

In particular, by a slow change of the process parameters and in particular by a change in the ratio of the first process gas d and second process gas G2 during the deposition gradient in the material composition of the barrier layer 4 are generated.

The following table shows the results of an aging test for three exemplary functional elements according to the invention Example 1 to 3 with protective layers 4 according to the invention and a comparative example according to the prior art without a protective layer according to the invention:

The aging test consists of a heat storage of the laminated, coated functional element of four weeks at 90 ° C.

Functional elements according to the invention, in which the protective layer 4 consists of a single protective layer 4.1, show in comparison with the comparative example a significantly improved resistance in the aging test. A two-layer protective layer 4 of a first individual protective layer 4.1 made of organosilicon (SiO _x C _y : H) and a silicon oxide-based second single layer 4.2 show a further improved aging resistance. FIGS. 4A and 4B each show a detail of an exemplary composite pane 100 according to the invention as a windshield with an electrically controllable sun visor. The composite disk 100 from FIGS. 4A and 4B essentially corresponds to the composite disk 100 from FIGS. 1A-C, so that only the differences are discussed below.

The windshield comprises a trapezoidal composite disk 100 with an outer disk 1 and an inner disk 2, which are interconnected via two intermediate layers 3a, 3b. The outer pane 1 has a thickness of 2.1 mm and consists of a green-colored soda-lime glass. The inner pane 2 has a thickness of 1, 6 mm and consists of a clear soda-lime glass. The windshield has an upper edge D facing the roof in the installed position and a lower edge M facing the engine compartment in the installed position. The windscreen is equipped with an electrically controllable functional element 5 according to the invention as a sun visor, which is arranged in an area above the central viewing area B (as defined in ECE-R43). The sun visor is formed for example by a commercially available PDLC multilayer film as a functional element 5, which is embedded in the intermediate layers 3a, 3b. The height of the sun visor is for example 21 cm. The first intermediate layer 3 a is connected to the outer pane 1, the second intermediate layer 3 b is connected to the inner pane 2. An intervening third intermediate layer 3c has a cutout in which the cut PDLC multilayer film is inserted accurately, that is flush on all sides. The third intermediate layer 3c layer thus forms, as it were, a kind of passe-partout for the functional element 5, which is thus encapsulated all round in thermoplastic material and thus protected.

The first intermediate layer 3a has a tinted region 6, which is arranged between the functional element 5 and the outer pane 1. The light transmission of the windshield is thereby additionally reduced in the region of the functional element 5 and the milky appearance of the PDLC functional element 5 is attenuated in the diffuse state. The aesthetics of the windshield are thus made much more appealing. The first intermediate layer 3a has an average light transmission of 30% in the region 6, for example, with which good results are achieved.

The area 6 can be homogeneously tinted. Often, however, it is more visually appealing when the tint in the direction of the lower edge of the functional element 5 is lower, so that the tinted and untoned area merge smoothly into one another. In the illustrated case, the lower edges of the tinted region 6 and the lower edge of the PDLC functional element 5 (here the lateral surface 5.1 thereof) are arranged flush with the barrier layer 4. This is not necessarily the case. It is also possible that the tinted region 6 protrudes beyond the functional element 5 or conversely that the functional element 5 projects beyond the tinted region 6. In the latter case would not be the entire functional element 5 is connected to the outer pane 1 via the tinted area 6.

The windshield has, as usual, a peripheral peripheral covering pressure 9, which is formed by an opaque enamel on the inside surfaces (facing the interior of the vehicle in the installed position) of the outer pane 1 and the inner pane 2. The distance of the functional element 5 to the upper edge D and the side edges of the windshield is smaller than the width of the cover pressure 9, so that the side surfaces of the functional element 5 - with the exception of the central field of view B facing side edge - are covered by the cover pressure 9. The electrical connections, not shown, are expediently mounted in the region of the covering pressure 9 and thus hidden.

The controllable functional element 5 is a multilayer film consisting of an active layer 11 between two surface electrodes 12, 13 and two carrier foils 14, 15. The active layer 11 contains a polymer matrix with liquid crystals dispersed therein, which are applied as a function of the surface electrodes align electrical voltage, whereby the optical properties can be controlled. The carrier films 14, 15 are made of PET and have a thickness of, for example, 0.125 mm. The carrier foils 14, 15 are provided with a coating of ITO having a thickness of approximately 100 nm facing the active layer 11, which form the electrodes 12, 13. The electrodes 12, 13 are connectable via not shown bus bars (for example, formed by a silver-containing screen printing) and not shown connection cable with the on-board electrical system.

On the side surfaces 5.1, 5.2, 5.3 and 5.4 of the functional element 5, for example, a barrier layer 4 is arranged, analogous to Figure 1 C. In the example shown, all side surfaces 5.1, 5.2, 5.3 and 5.4 are completely sealed with the barrier layer 4. As a result, the functional element 5 is particularly well protected against aging.

For the intermediate layers 3a, 3b, 3c, a so-called "high-flow PVB" may be used, which has a greater flow behavior compared to standard PVB films, so that the layers become more fluid around the barrier layer 4 and the functional element 5 a more homogeneous visual impression is created and the transition from functional element 5 to intermediate layer 3c is less noticeable Flow PVB "may be used for all or even only one or more of the intermediate layers 3a, 3b, 3c.

In another example not shown here, the windshield and the functional element 5 with barrier layer 4 essentially correspond to the embodiment from FIGS. 4A and 4B. However, the PDLC functional element 5 is divided by horizontal isolation lines into, for example, six strip-like segments. The insulation lines have, for example, a width of 40 μm to 50 μm and a mutual distance of 3.5 cm. They have been introduced by means of a laser in the prefabricated multilayer film. In particular, the insulation lines separate the surface electrodes into strips insulated from one another, each of which has a separate electrical connection. Thus, the segments are independently switchable. The thinner the insulation lines are made, the less inconspicuous they are. By means of etching even thinner insulation lines can be realized.

By segmentation, the height of the darkened functional element 5 can be adjusted. Depending on the position of the sun, the driver can thus darken the entire sun visor or only a part of it. In a particularly convenient embodiment, the functional element 5 is controlled by a capacitive button arranged in the region of the functional element, the driver determining the degree of darkening by the location where he touches the pane. Alternatively, the functional element 5 can also be controlled by non-contact methods, for example by detecting gestures, or in dependence on the state of the pupil or eyelid detected by a camera and suitable evaluation electronics.

A further aspect of the invention comprises a functional element (5) with electrically controllable optical properties, comprising

a stacking sequence of at least:

a first carrier foil (15),

- an active layer (1 1) and

a second carrier foil (14),

wherein at least one exit surface (8) of the active layer (1 1) at least one side surface (5.1, 5.2, 5.3, 5.4) of the functional element (5) at least partially sealed with at least one barrier layer (4). A further aspect of the invention comprises a functional element (5) with electrically controllable optical properties, comprising

a stacking sequence of at least:

a first carrier foil (15),

- an active layer (1 1) and

a second carrier foil (14),

wherein at least one exit surface (8) of the active layer (1 1) at least one side surface (5.1, 5.2, 5.3, 5.4) of the functional element (5) is at least partially sealed with at least one barrier layer (4) and the barrier layer (4) in one layer is formed of a single layer (4.1) or of several layers of at least two individual layers (4.1, 4.2),

wherein the single layer (4.1) or at least one single layer (4.1, 4.2) of the barrier layer (4) contain or consist of the following materials:

a) metal oxide-based, metal nitride-based or metal oxynitride-based layers, wherein the metal is preferably silicon (Si), aluminum (AI), tantalum (Ta) or vanadium (V) or

Mixtures thereof, preferably substoichiometric or stoichiometric silicon oxide layers,

b) organometallic layers, preferably SiO x Cy: organosilicon layers: H, preferably with x from 0.1 to 3 and y greater than 0.3,

c) amorphous hydrogenated carbon (a-C: H), preferably amorphous hydrogenated nitrogen-doped carbon (a-C: N: H) or amorphous hydrogenated carbon doped with nitrogen and silicon (a-C: N: Si: H)

and or

d) other ceramic layers which can be produced by gas-phase deposition processes and / or polymer layers which reduce or substantially prevent the diffusion of plasticizers, preferably parylene, polyvinylidene chloride (PVDC), ethylene-vinyl alcohol copolymers (EVOP) or polyacrylates,

and preferably the entire barrier layer (4) over the exit surface (8) has a thickness d of 10 nm to 5000 nm (nanometers), more preferably from 15 nm to 1000 nm and most preferably from 15 nm to 500 nm.

Advantageously, the exit surfaces (8) on all side surfaces (5.1, 5.2, 5.3, 5.4) completely sealed with the barrier layer (4) or at least one of the side surfaces (5.1, 5.2, 5.3, 5.4) and preferably all side surfaces (5.1, 5.2, 5.3, 5.4) completely sealed with the barrier layer (4). Advantageously, the functional element (5) is a polymer dispersed liquid crystal (PDLC) functional element.

LIST OF REFERENCE NUMBERS

I outer pane

2 inner pane

3a first intermediate layer

3b second intermediate layer

3c third intermediate layer

4 barrier layer

4.1, 4.2 single layer of the barrier layer 4

5 functional element with electrically controllable optical properties 5.1, 5.2, 5.5, 3.5.4 side surface of the functional element 5

6 tinted area of the first intermediate layer 3a

8 exit surface of the active layer 1 1

9 cover printing

I I active layer of the functional element 5

12 surface electrode of the functional element 5

13 surface electrode of the functional element 5

14 carrier film

15 carrier film

20 gas phase separation plant

21 vacuum chamber

22 high-frequency generator

23 Adaptation electronics

24 cathode

25 anodes

26 sample holders

27 plasma zone

28 vacuum pump

30.1 first gas inlet

30.2 second gas inlet

31 gas outlet

100 composite pane B central field of vision of the windscreen D top of windshield, roof edge d thickness, material thickness

Gi first process gas

G2 second process gas

M lower edge of the windscreen, engine edge U supernatant

Χ-Χ 'cutting line

Z, Ζ ', Ζ "enlarged area

Claims

claims

Composite disc (100) having a functional element (5) with electrically controllable optical properties, comprising:

a stacking sequence 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 polymeric film with at least one plasticizer and

between the first intermediate layer (3a) and the second intermediate layer (3b) at least in sections a functional element (5) with electrically controllable optical properties is arranged, and

the functional element (5) is a polymer dispersed liquid crystal (PDLC) functional element,

wherein the functional element (5) comprises a second stacking sequence of at least

a first carrier foil (15),

- an active layer (1 1) and

- Includes a second carrier film (14), and

wherein at least one exit surface (8) of the active layer (1 1) is sealed to at least one side surface (5.1, 5.2, 5.3, 5.4) of the functional element (5) at least in sections with at least one barrier layer (4),

the barrier layer (4) is designed such that it substantially prevents the diffusion of plasticizer through the barrier layer (4) and

the barrier layer (4) is made by a vacuum-based thin-film deposition process.

The composite disc (100) of claim 1, wherein the vacuum-based thin-film deposition method is one of the following methods:

o Physical vapor deposition (PVD), particularly preferred

• evaporate, like

o thermal evaporation,

o electron beam evaporation

o laser beam evaporation

o Ion Assisted Deposition (IAO) or o Arc evaporation

or

• sputtering, such as

o magnetron sputtering

o Atomic layer deposition (Atomic Layer Depositon), like

^■ Plasma-enhanced atomic layer deposition (Plasma Enhanced Atomic Layer Deposition, PEALD)

and or

o Chemical vapor deposition (CVD), particularly preferred

• Plasma Enhanced Chemical Vapor Deposition (PECVD).

Composite disc (100) according to claim 1 or claim 2, wherein the exit surfaces (8) on all side surfaces (5.1, 5.2, 5.3, 5.4) are completely sealed with the barrier layer (4) or at least one of the side surfaces (5.1, 5.2, 5.3 , 5.4) and preferably all side surfaces (5.1, 5.2, 5.3, 5.4) are completely sealed with the barrier layer (4).

A composite disk (100) according to any one of claims 1 to 3, wherein the barrier layer (4) is adapted to inhibit the diffusion of plasticizer through the barrier layer (4) to the same extent as the diffusion of plasticizer through the backing films (14) , 15).

Composite disk (100) according to one of claims 1 to 4, wherein the barrier layer (4) is formed in one layer from a single layer (4.1) or in multiple layers from at least two individual layers (4.1, 4.2).

Composite disc (100) according to claim 5, wherein the single layer (4.1) or at least one single layer (4.1, 4.2) of the barrier layer (4) contain or consist of the following materials:

a) metal oxide-based, metal nitride-based or metal oxynitride-based layers, wherein the metal is preferably silicon (Si), aluminum (AI), tantalum (Ta) or vanadium (V) or mixtures thereof, preferably substoichiometric or stoichiometric silicon oxide layers . b) organometallic layers, preferably organosilicon layers of the type SiO _x C _y : H, preferably with x from 0.1 to 3 and y greater than 0.3,

and or

d) other ceramic layers and / or polymer layers which can be produced by gas-phase deposition processes and which reduce or substantially prevent the diffusion of plasticizers, preferably parylene, polyvinylidene chloride (PVDC), ethylene-vinyl alcohol copolymers (EVOP) or polyacrylates.

Composite disc (100) according to one of claims 1 to 6, wherein the entire barrier layer (4) over the exit surface (8) has a thickness d of 10 nm to 5000 nm (nanometers), preferably from 15 nm to 1000 nm and more preferably from 15 nm to 500 nm.

Composite disc (100) according to one of claims 1 to 7, wherein the barrier layer (4) directly on the side surface (5.1, 5.2, 5.3, 5.4) of the stacking sequence of the functional element (5) and in particular directly on the exit surface (8) of the active layer (1 1) and / or the side surfaces of the carrier films (14,15) is arranged.

Composite disc (100) according to one of claims 1 to 8, wherein the barrier layer (4) consists of at least a first single layer (4.1) of an organosilicon compound of the SiO _x C _y : Hz type and a second silicon oxide-based single layer (4.2) Preferably, the first single layer (4.1) is arranged directly on the stacking sequence of the functional element (5) and the second single layer (4.2) is particularly preferably arranged directly on the first single layer (4.1)

Composite disc (100) according to one of claims 1 to 9, wherein the intermediate layer (3a, 3b) at least 3 wt .-%, preferably at least 5 wt .-%, particularly preferably at least 20 wt .-%, more preferably at least 30 wt .-% and in particular at least 40 wt .-% of a plasticizer and the plasticizer preferably aliphatic diesters of tri- or tetraethylene glycol, more preferably triethylene glycol bis (2-ethylhexanoate), contains or consists thereof.

1 1. Composite disc (100) according to one of claims 1 to 10, wherein the intermediate layer (3a, 3b) 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).

12. A method for producing a functional element (5) with electrically controllable optical properties, wherein at least

a) a stacking sequence of at least

a first carrier foil (15),

- an active layer (1 1) and

a second carrier foil (14)

is provided and

b) an exit surface (8) of the active layer (1 1) at least one side surface (5.1, 5.2, 5.3, 5.4) of the functional element (5) is at least partially sealed with a barrier layer (4), wherein preferably the barrier layer (4) by a vacuum-based thin-film deposition process, and preferably by a PECVD process.

13. The method of claim 12, wherein in a subsequent process step

c) an outer pane (1), a first intermediate layer (3a), the functional element (5) with electrically controllable optical properties, a second intermediate layer (3b) and an inner pane (2) are arranged one above the other in this order, and

d) the outer pane (1) and the inner pane (2) are joined by lamination, wherein an intermediate layer with incorporated functional element (5) is formed from the first intermediate layer (3a) and the second intermediate layer (3b).

14. Use of a composite pane (100) according to any one of claims 1 to 1 1 as

Windscreen or roof glass of a vehicle, wherein the functional element (5) is used as a sun visor.

15. Use of a composite pane (100) according to any one of claims 1 to 1 1 as interior glazing or exterior glazing in a vehicle or a building, wherein the electrically controllable functional element (5) is used as a sunscreen or as a screen.