DE202021100685U1 - Functional element with electrically controllable optical properties and an active layer comprising spacers - Google Patents

Abstract

Functional element (5) with electrically controllable optical properties at least comprising a multilayer film (6) containing at least one above the other in this order in terms of area
- a first carrier film (13.1),
- a first surface electrode (12.1),
- an active layer (7),
- a second surface electrode (12.2),
- A second carrier film (13.2), wherein the active layer (7) is electrically conductively contacted by the first surface electrode (12.1) and the second surface electrode (12.2) and the active layer (7) comprises degradable spacers (14) which are chemically Reaction with other components of the active layer are degradable and / or are degradable by physical environmental influences.

Description

The invention relates to a functional element with electrically controllable optical properties and an active layer comprising spacers and a composite pane comprising such a functional element.

In the vehicle sector and in the construction sector, composite panes with electrically controllable functional elements are often used for sun protection or privacy protection.

For example, windshields are known in which a sun visor in the form of a functional element with electrically controllable optical properties is integrated. In particular, the transmission or the scattering behavior of electromagnetic radiation in the visible range can be controlled electrically. The functional elements are usually multilayer films that are laminated into or glued to a composite pane. These multilayer films generally comprise an active layer between two surface electrodes, the arrangement mostly being stabilized by carrier films. The transmission properties of the active layer can be changed by applying a voltage to the active layer via the surface electrodes. In the case of windshields, the driver can control the transmission behavior of the window with respect to solar radiation. This means that there is no need for a conventional mechanical sun visor. This allows the weight of the vehicle to be reduced and space is gained in the roof area.

Windshields with such electrically controllable sun visors are known from, for example WO 2014/086555 A1 , DE 102013001334 A1 , DE 102005049081 B3 , DE 102005007427 A1 and DE 102007027296 A1 . In addition, functional elements are also used to shade vehicle glazing as roof panes, for example in EP 2010385 B1 described.

Typical functional elements for implementing electrically controllable sun protection are so-called PDLC functional elements (polymer dispersed liquid crystal). Their active layer contains liquid crystals which are embedded in a polymer matrix. If no voltage is applied, the liquid crystals are disordered, which leads to a strong scattering of the light passing through the active layer. If a voltage is applied to the surface electrodes, the liquid crystals align in a common direction and the transmission of light through the active layer is increased. The PDLC functional element works less by reducing the overall transmission, but by increasing the scattering in order to ensure protection against glare.

Laminated functional elements and in particular PDLC functional elements often show undesirable signs of aging, such as lightening and changes in shading, in the edge area. The reason for this is considered to be the diffusion of compounds, in particular plasticizers, from the thermoplastic composite films of the composite pane into the active layer of the functional element. Sealing the edge area of the functional element prevents diffusion and provides a remedy, for example according to US 20110171443 A1 by applying an adhesive tape that closes the open edge of the active layer.

The PDLC functional elements described generally include an active layer between two flat electrodes applied to carrier films. PET films, for example, which are provided with indium tin oxide (ITO) layers as surface electrodes, are used as carrier films. When a voltage is applied, an electric field is created between the flat electrodes, in which the liquid crystals of the active layer align themselves, as a result of which the PDLC functional element is switched to the transparent state. In addition to liquid crystals, the active layer of the PDLC functional element comprises a polymer matrix in which the liquid crystals are embedded. In order to achieve a homogeneous appearance of the PDLC functional element, the layer thickness of the gel-like polymeric matrix should be as homogeneous as possible. For this purpose, spherical spacers are often used, which are introduced into the active layer when the functional element is manufactured. These spherical spacers determine the distance between the carrier films, between which the active layer is introduced. Thus, by adding spacers, a homogeneous layer thickness of the active layer is ensured, whereby a constant amount of liquid crystals per unit area is present in the entire product, which cause light scattering in the opaque state of the functional element.

A frequently used method for producing PDLC films is the so-called roll-to-roll process, in which the carrier films provided with flat electrodes are unrolled from one roll each, the material of the active layer and the PDLC obtained therefrom are introduced between the carrier films -Film can optionally be rolled up again on a roll. The surfaces of the PDLC film facing away from the active layer are preferably provided with protective films which prevent the film from being scratched. After the carrier foils coated with surface electrodes have unrolled have been, these are placed at a distance from one another via rollers and the material of the active layer is injected into the space. It should be noted that the rollers that press the stack of layers of carrier films and the active layer in between should not lead to an inhomogeneous distribution of the active layer. For this purpose, small spherical spacers are added to the active layer, the diameter of which corresponds approximately to the desired layer thickness of the active layer. These spacers are made of polymers or silica, for example. Using such spacers results in a very constant thickness of the active layer in the roll-to-roll process and, as a result, a homogeneous distribution of the liquid crystals.

The spherical spacers used in the roll-to-roll process remain in the product. This has the decisive disadvantage that undesirable light scattering takes place at the spacers when the PDLC functional element is installed. For example, a so-called rainbow effect occurs in vehicle roof glazing with such a PDLC functional element. This is perceived as visually disruptive and does not meet the requirements for the transparency of the glazing when the functional element is activated. In addition, the known functional elements with spacers show an undesirably increased haze and the spacers may even be visible to the human eye as microscopic unevenness.

The present invention is therefore based on the object of providing an improved functional element which does not have the disadvantages of the prior art and a composite pane comprising such a functional element.

The object of the present invention is achieved by a functional element according to the independent protection claim 1 solved. Preferred embodiments emerge from the subclaims.

• - eine erste Trägerfolie,
• - eine erste Flächenelektrode,
• - eine aktive Schicht,
• - eine zweite Flächenelektrode,
• - eine zweite Trägerfolie,

wobei die aktive Schicht von der ersten Flächenelektrode und der zweiten Flächenelektrode elektrisch leitend kontaktiert ist und die aktive Schicht abbaubare Abstandhalter umfasst, die durch chemische Reaktion mit anderen Komponenten der aktiven Schicht abbaubar sind und/oder durch physikalische Umgebungseinflüsse abbaubar sind.The invention relates to a functional element with electrically controllable optical properties at least comprising a multilayer film containing at least one above the other in this order in terms of area

• - a first carrier film,
• - a first surface electrode,
• - an active layer,
• - a second surface electrode,
• - a second carrier film,

wherein the active layer is electrically conductively contacted by the first surface electrode and the second surface electrode and the active layer comprises degradable spacers which are degradable by chemical reaction with other components of the active layer and / or are degradable by physical environmental influences.

The functional element is preferably a PDLC (polymer dispersed liquid crystal) functional element. The active layer of a PDLC functional element contains liquid crystals which are embedded in a gel-like polymer matrix. If no voltage is applied to the surface electrodes, the liquid crystals are disordered, which leads to a strong scattering of the light passing through the active layer. If a voltage is applied to the surface electrodes, the liquid crystals align in a common direction and the transmission of light through the active layer is increased. Such a functional element is off, for example DE 102008026339 A1 known. The active substance of a PDLC functional element are therefore liquid crystals, which are dispersed in the form of liquid crystal droplets in a matrix, in this case a polymer matrix. The polymer matrix and the liquid crystal droplets dispersed therein together form the active layer.

The active layer of the functional element further comprises the degradable spacers according to the invention or their degradation products.

After the production of the functional element, depending on the choice of degradable spacers, these can be removed by means of various mechanisms. For example, degradable spacers can be used, which degrade under certain environmental conditions. These include, for example, spacers that degrade under the influence of light, under UV light and / or under microwave radiation. Furthermore, spacers which can be degraded under the influence of other radiation, when heated or under the influence of sound waves are also conceivable. Alternatively, degradable spacers can be used which are soluble in the gel-like matrix of the active layer or react with components of the active layer and are degraded in the process. A reaction with other components of the active layer could also be started or accelerated via the aforementioned physical environmental influences, depending on the composition of the spacers and the type of degradation reaction.

The functional element according to the invention thus has the decisive advantage that, on the one hand, a homogeneous thickness of the functional element can be ensured via the particles that serve as spacers and, on the other hand, after a certain period of time and / or under certain conditions Environmental influences the spacers are broken down and thus no longer show any disruptive influences in the product.

The functional element according to the invention can be manufactured in the roll-to-roll process, the degradable spacers being admixed with the gel-like matrix of the active layer and being injected with this into the space between the carrier films. In this respect, no adaptation of the production process is necessary. Only if the degradable spacers are soluble in the gel-like PDLC matrix or the degradation process is based on a reaction with matrix components, these should only be added shortly before the active layer is injected between the carrier films in order to avoid premature degradation of the spacers.

In a preferred embodiment of the invention, the degradable spacers are not spherical. The degradable spacers are particularly preferably rod-shaped. The rod-shaped spacers can be designed with the same diameters as the spacers known in the prior art. The rod-shaped shape and the irregular size and orientation of the rod-shaped spacers mean that the visually disruptive rainbow effect can be avoided. Such a rod-shaped configuration of the spacers is not only conceivable for further optimization of the degradable spacers according to the invention, but can also be used to improve the non-degradable spacers known from the prior art.

The degradable spacers according to the invention can be made in the usual sizes of the spacers known from the prior art and have, for example, diameters of 5 μm to 50 μm.

The functional element with electrically controllable optical properties is an element whose optical properties can be regulated as a function of the applied voltage. As a rule, the surface electrodes are each applied to the carrier film adjacent to them.

The controllable functional element comprises at least one active layer between two flat electrodes. The active layer has the controllable optical properties, which can be controlled via the voltage applied to the surface electrodes. The area electrodes and the active layer are typically arranged essentially parallel to one another. The surface electrodes can be electrically connected to an external voltage source in a manner known per se. The electrical contact can be realized by suitable connecting 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 prints.

The carrier films preferably contain at least one polymer that does not completely melt in the autoclave process, preferably polyethylene terephthalate (PET). The first and the second carrier film particularly preferably consist of a PET film. The carrier films according to the invention are preferably transparent, but can also be tinted. The thickness of the carrier films is preferably from 0.025 mm to 0.400 mm, in particular from 0.050 mm to 0.200 mm. The flat electrodes are preferably arranged on a surface of the carrier film, that is to say on exactly one of the two sides of the carrier film (that is to say on its front side or its rear side). The carrier films are aligned in the layer stack of the multilayer film in such a way that the surface electrodes are arranged adjacent to the active layers. The films can also have various thicknesses and compositions within the stated ranges.

The carrier films are preferably designed as a single continuous film in the area of the entire functional element. This enables a high optical product quality to be achieved. In contrast to this, in a functional element that is produced from a plurality of multilayer films placed next to one another on a cut edge, the cut edge remains visible even after the functional element has been laminated in a pane.

Electrically controllable optical properties are understood in the context of the invention to be those properties that can be continuously regulated, but equally also those that can be switched between two or more discrete states.

The flat electrodes are preferably designed as transparent, electrically conductive layers. The surface electrodes preferably contain at least one metal, a metal alloy or a transparent conductive oxide (transparent conducting oxide, TCO). The flat electrodes can contain, for example, silver, gold, copper, nickel, chromium, tungsten, indium tin oxide (ITO), gallium-doped or aluminum-doped zinc oxide and / or fluorine-doped or antimony-doped tin oxide. The surface electrodes preferably have a thickness of 10 nm to 2 μm, particularly preferably from 20 nm to 1 μm, very particularly preferably from 30 nm to 500 nm.

The surface electrodes are electrically connected to an external voltage source in a manner known per se. The electrical contact is made by means of suitable connecting cables, for example foil conductors, which are preferably connected to the flat electrodes via bus bars.

In addition to the active layer and the surface electrodes, the multilayer film can have further layers known per se, for example barrier layers, blocker layers, antireflection layers, protective layers and / or smoothing layers.

The invention further relates to a composite pane comprising a functional element according to the invention with electrically controllable optical properties, the optical properties of which can be regulated as a function of the applied voltage. The functional element is embedded in the intermediate layer of the composite pane. The intermediate layer connects the first pane and the second pane of the composite pane. The controllable functional element comprises an active layer which has controllable optical properties. For this purpose, the active layer contains an active substance, the optical properties of which can be changed as a function of the voltage applied to the functional element.

The flat electrodes and the active layer of the functional element are typically arranged essentially parallel to the inner pane and outer pane of the composite pane.

The composite pane can be, for example, the windshield or the roof pane of a vehicle or some other vehicle glazing, for example a partition in a vehicle, preferably in a rail vehicle or a bus. Alternatively, the composite pane can be architectural glazing, for example in an outer facade of a building or a partition pane inside a building.

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

If the composite pane is intended to separate an interior space from the external environment in a window opening of a vehicle or building, the interior pane (second pane) facing the interior (vehicle interior) is referred to as an inner pane in the context of the invention. The outer pane is the term for the pane (first pane) facing the external environment. However, the invention is not restricted to this.

The composite pane according to the invention contains a functional element with electrically controllable optical properties, which is arranged at least in sections between a first thermoplastic composite film and a second thermoplastic composite film. The first and second thermoplastic composite films usually have the same dimensions as the first and second panes.

In an advantageous embodiment, the composite pane according to the invention is a windshield of a motor vehicle. This comprises an engine edge which is adjacent to the engine hood when the composite pane is installed in the vehicle body, and a roof edge which is adjacent to the vehicle roof when installed. The edge of the motor and the roof edge form two opposite window edges. Between the edge of the engine and the edge of the roof, two opposite side edges run which, when the windshield is installed, border on the so-called A-pillars of the body.

Windshields have a central field of vision, the optical quality of which is subject to high requirements. The central field of view must have a high light transmission (typically greater than 70%). Said central field of vision is in particular that field of vision which is referred to by the person skilled in the art as field of vision B, field of vision B or zone B. Field of vision B and its technical requirements are specified in Regulation No. 43 of the United Nations Economic Commission for Europe (UN / ECE) (ECE-R43, "Uniform Conditions for Approval of Safety Glazing Materials and Their Installation in Vehicles"). Field of vision B is defined there in Appendix 18.

The composite pane is particularly preferably the roof pane of a motor vehicle.

In one embodiment of the invention, the functional element is divided into segments by dividing lines, also referred to as isolation lines. The dividing lines are in particular introduced into the surface electrodes, so that the segments of the surface electrode are electrically isolated from one another. At least one of the surface electrodes has at least one dividing line which divides the surface electrode into at least two segments, the electrically controllable optical properties of which can be switched independently of one another. The individual segments are connected to the voltage source independently of one another so that they can be controlled separately. For example different areas of the roof pane can be switched independently. The dividing lines and the segments are particularly preferably arranged horizontally in the installed position of a windshield or roof window with a sun visor. This allows the height of the sun visor to be regulated by the user. The term “horizontal” is to be interpreted broadly here and denotes a direction of propagation that runs between the side edges of the windshield or between the side edges of a roof glazing adjacent to the vehicle doors. The dividing lines do not necessarily have to be straight, but can also be slightly curved, preferably adapted to a possible bending of the edge of the pane. Vertical dividing lines are of course also conceivable.

The dividing 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 dividing lines, can be suitably selected by a person skilled in the art according to the requirements in the individual case.

The dividing lines can be introduced by laser ablation, mechanical cutting or etching during the production of the functional element. Multi-layer films that have already been laminated can also be segmented subsequently by means of laser ablation.

The functional element is integrated between the inner pane and the outer pane of the composite pane via a thermoplastic intermediate layer. The intermediate layer preferably comprises a first thermoplastic composite film, which connects the functional element to the inner pane, and a second thermoplastic composite film, which connects the functional element to the outer pane. Typically, the thermoplastic intermediate layer is formed by at least the first and the second thermoplastic composite film, which are arranged flat on top of one another and laminated to one another, the functional element being inserted between the two layers. The areas of the composite films that overlap with the functional element then form the areas that connect the functional element to the panes. In other areas of the pane where the thermoplastic composite films are in direct contact with one another, they can fuse during lamination in such a way that the two original layers may no longer be recognizable and instead a homogeneous intermediate layer is present.

A thermoplastic composite film can be formed, for example, by a single thermoplastic film. A thermoplastic composite film can also be formed from sections of different thermoplastic films, the side edges of which are placed against one another. In addition to a first thermoplastic composite film or a second thermoplastic composite film, further thermoplastic composite films can also be present. If necessary, these can also be used to embed further films comprising functional layers, for example infrared-reflecting layers or acoustically damping layers.

In one possible embodiment of the invention, the functional element, more precisely the side edges of the functional element, is surrounded all around by a thermoplastic frame film. The thermoplastic frame film has approximately the same thickness as the functional element. Thus, local differences in thickness of the composite pane, which are introduced by small-area, locally limited functional elements, are compensated for by such a frame film, so that glass breakage during lamination can be avoided. The thermoplastic frame film can be formed by a thermoplastic film into which the recess has been made by cutting out.

Optionally, the peripheral edge of the functional element can be completely or partially provided with an edge seal. This can be placed around the open edge of the functional element in the form of an adhesive tape, for example. The edge sealing prevents plasticizers from diffusing from the thermoplastic composite films into the active layer of the functional element.

Optionally, at least a partial area of the first and / or the second thermoplastic composite film is tinted or colored. The transmission of this range in the visible spectral range is therefore reduced compared to a non-tinted or colored layer. The tinted / colored area of the thermoplastic composite films thus lowers the transmission of the composite pane. In particular, the aesthetic impression of the functional element is improved because the tint leads to a more neutral appearance that is more pleasant to the viewer. The tinted or colored area can be colored or tinted homogeneously, that is to say have a location-independent transmission. The tint or coloration can, however, also be inhomogeneous, in particular a transmission profile can be implemented.

In particular when the composite pane is used as the roof pane of a motor vehicle, one or more panes and / or one or more thermoplastic composite films are tinted.

The thermoplastic intermediate layer, comprising the first and second thermoplastic composite films and any further polymeric films, are not tinted or colored in the central field of vision of a windshield, but clear and transparent. This ensures that the view through the central field of vision is not restricted, so that the pane can be used as a windshield. A transparent thermoplastic composite film is a layer with a light transmission in the visible spectral range of at least 70%, preferably at least 80%. The transparent intermediate layer is present at least in field of view A, preferably also in field of view B according to ECE-R43.

If the composite pane according to the invention is a motor vehicle pane, one or more edges of the functional element are preferably covered by an opaque cover print when looking through the pane. Windshields and roof windows typically have a circumferential, peripheral cover print made of an opaque enamel, which is used in particular to protect the adhesive used for installing the windshield from UV radiation and to cover it optically. This peripheral cover print is preferably used to also cover the edges of the functional element, as well as the required electrical connections. Both the outer pane and the inner pane preferably have a cover print so that viewing from both sides is prevented.

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, the function of which would be impaired by a controllable functional element in the beam path, for example rain sensors.

The functional element is preferably arranged over the entire width of the composite pane, minus an edge region on both sides with a width of, for example, 2 mm to 20 mm. The functional element is also preferably at a distance of, for example, 2 mm to 20 mm from the upper edge. The functional element is encapsulated within the intermediate layer and protected from contact with the surrounding atmosphere and corrosion.

The electrical control of the functional element takes place, for example, by means of switches, rotary controls or slide controls that are integrated in the vehicle's fittings. However, a control button can also be integrated in the windshield and / or in the roof surface of a motor vehicle, for example a capacitive button. Alternatively or additionally, the functional element can be controlled by non-contact methods, for example by recognizing gestures, or as a function of the pupil or eyelid state determined by a camera and suitable evaluation electronics. A control as a function of the eyelid or pupil state is particularly possible in the case of functional elements as the sun visor of a windshield. Alternatively or additionally, the functional element can be controlled by sensors which detect the incidence of light on the pane.

The first thermoplastic composite film and the second thermoplastic composite film and optionally also further thermoplastic composite films preferably contain at least polyvinyl butyral (PVB), ethylene vinyl acetate (EVA) and / or polyurethane (PU), particularly preferably PVB.

The thickness of each thermoplastic composite film 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 0.5 mm, for example 0.38 mm.

The outer pane and the inner pane are preferably made from glass, particularly preferably from soda-lime glass, as is customary for window panes. The panes can, however, also be made of other types of glass, for example quartz glass, borosilicate glass or alumino-silicate glass, or of rigid, clear plastics, for example polycarbonate or polymethyl methacrylate. The outer pane and / or the inner pane can be pre-stressed thermally or chemically. In particular, thin inner panes with a thickness of less than or equal to 1 mm are preferably made from chemically toughened aluminosilicate glass. The panes can be clear, tinted or colored. However, a windshield must have sufficient light transmission in the central viewing area, preferably at least 70% in the main viewing area A in accordance with ECE-R43.

The outer pane, the inner pane and / or the intermediate layer can have further suitable coatings known per se, for example anti-reflective coatings, non-stick coatings, anti-scratch coatings, photocatalytic coatings or sun protection coatings or low-E coatings.

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

• 1 eine Ausführungsform einer Mehrschichtfolie des erfindungsgemäßen Funktionselementes,
• 2a eine erfindungsgemäße Verbundscheibe als Dachscheibe eines Kraftfahrzeugs,
• 2b einen Querschnitt entlang der Schnittlinie AA` durch die Verbundscheibe gemäß 2a.

The invention is explained in more detail with reference to a drawing and exemplary embodiments. The drawing is a schematic representation and not to scale. The drawing does not restrict the invention in any way. Show it:

• 1 an embodiment of a multilayer film of the functional element according to the invention,
• 2a a composite pane according to the invention as a roof pane of a motor vehicle,
• 2 B a cross section along the section line AA` through the laminated pane according to 2a .

1 shows a cross section through a multilayer film 6th of the functional element according to the invention 5 . The multilayer film 6th is a PDLC multilayer film. The multilayer film 6th consists of an active layer 7th between flat electrodes 12th and carrier foils 13th . On a first carrier film 13.1 is a first surface electrode 12.1 appropriate. The second carrier film 13.2 carries the second surface electrode on one surface 12.2 . The active layer 7th is located between the first surface electrode 12.1 and the second surface electrode 12.2 and is contacted by these in an electrically conductive manner. The active class 7th contains a matrix with an active substance therein. In the case of a PDLC multilayer film, the matrix is formed by a polymer matrix in which liquid crystals dispersed therein are contained as the active substance. The liquid crystals are in the form of drops with a drop size of a few µm. The liquid crystals are directed depending on the respective adjacent surface electrodes 12th applied electrical voltage, thereby reducing the optical properties of the active layers 7th can be controlled. The carrier foils 13th consist of PET and have a thickness of 50 µm or 110 µm, for example. The carrier foils 13th can also have different thicknesses. The carrier foils 13th are with one to the adjacent active layers 7th facing coating made of ITO with a thickness of about 100 nm, which the surface electrodes 12th trains. The surface electrodes 12th can be connected to a voltage source via busbars (not shown) (for example formed by a silver-containing screen print) and connecting cables (not shown). The active layer 7th has degradable spacers 17th shown here before their demotion.

2a and 2 B represent an embodiment of a composite pane according to the invention 100 represents, which is shaped as a roof window of a motor vehicle. The roof pane includes an inner pane 1 , an outer pane 2 and a thermoplastic intermediate layer 3 , in which a multilayer film 6th according to 1 as a functional element 5 is stored. 2a Figure 10 shows a top view of the composite pane 100 as a roof window of a motor vehicle. 2 B shows a cross section through the composite pane according to FIG 2a along the section line AA '. The inner pane 1 and the outer pane 2 are curved congruently to each other. The outer pane of the glazing is oriented towards the vehicle environment, while the inner pane of the composite pane faces the vehicle interior. The outer pane 2 consists of clear soda-lime glass with a thickness of 2.1 mm. The inner pane 1 consists of soda-lime glass with a thickness of 1.6 mm and is tinted gray. The tinted inner glass contributes to the appealing appearance of the window, also for the vehicle occupant when looking through the roof window. The disks 1 , 2 are over the thermoplastic interlayer 3 with inlaid multilayer film 6th connected. The thermoplastic intermediate layer 3 comprises the first thermoplastic composite film 4.1 , the second thermoplastic composite film 4.2 . The thermoplastic composite films 4.1 , 4.2 each comprise a thermoplastic film made of PVB with a thickness of 0.38 mm. The functional element 5 , here in the form of a multilayer film 6th , is also about the thermoplastic composite films 4.1 , 4.2 on the panes 1 , 2 tied up. The functional element 5 can be controlled in its optical properties by applying an electrical voltage. The electrical leads are not shown for the sake of simplicity. Along the surrounding edge 8th of the functional element 5 is an edge seal 16 provided that the circumferential edge 8th encloses. The edge seal 16 can for example be in the form of an adhesive tape around the edge 8th to be glued. By means of the edge sealing 16 diffusion of the plasticizer out of the thermoplastic intermediate layer occurs 3 in the functional element 5 and an associated degradation of the functional element 5 avoided. The functional element 5 can be in the form of segments 14th can be switched variably. The functional element 5 is by horizontal dividing lines 15th in three segments 14th divided up. The dividing lines 15th electrical insulation of the segments 14th cause each other, for example, have a width of 40 µm to 120 µm. They are in the prefabricated multilayer film by means of a laser 6th has been introduced. Between adjacent dividing lines 15th are in the area of the opaque cover print 10 Busbar (not shown) attached. The bus bars of the individual segments 14th each have a separate electrical connection. So are the segments 14th switchable independently of each other. The thinner the dividing lines 15th are executed, the more inconspicuous they are. All three segments 14th can be switched completely transparent, non-transparent (one active layer non-transparent) or opaque (both active layers non-transparent) independently of one another. This is particularly advantageous with regard to the comfort of the vehicle occupants.

List of reference symbols

1

Inner pane

2

Outer pane

3

thermoplastic intermediate layer

4th

thermoplastic composite films

4.1

first thermoplastic composite film

4.2

second thermoplastic composite film

5

Functional element with electrically controllable optical properties

6th

Multilayer film

7th

active layer of the functional element 5

8th

circumferential edge of the functional element 5

10

opaque cover print

12th

Surface electrodes of the functional element 5

12.1

first surface electrode

12.2

second surface electrode

13th

Carrier foils

13.1

first carrier film

13.2

second carrier film

13.3

third carrier film

14th

Segments

15th

Dividing lines

16

Edge sealing

17th

degradable spacers

100

Composite pane

AA '

Cutting line

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• WO 2014/086555 A1 [0004]
• DE 102013001334 A1 [0004]
• DE 102005049081 B3 [0004]
• DE 102005007427 A1 [0004]
• DE 102007027296 A1 [0004]
• EP 2010385 B1 [0004]
• US 20110171443 A1 [0006]
• DE 102008026339 A1 [0013]

Claims (10)

Functional element (5) with electrically controllable optical properties at least comprising a multilayer film (6) containing at least one above the other in this order in terms of area - a first carrier film (13.1), - a first surface electrode (12.1), - an active layer (7), - a second surface electrode (12.2), - A second carrier film (13.2), wherein the active layer (7) is electrically conductively contacted by the first surface electrode (12.1) and the second surface electrode (12.2) and the active layer (7) comprises degradable spacers (14) which are chemically Reaction with other components of the active layer are degradable and / or are degradable by physical environmental influences. Functional element (5) after Claim 1 wherein the functional element (5) is a PDLC element and the active layers (7) are PDLC layers. Functional element (5) after Claim 1 or 2 , the degradable spacers (14) degrading under the influence of light, under UV light, under microwave irradiation, under the influence of other radiation, on heating and / or under the influence of sound waves and / or being soluble in the matrix of the active layer (7) and / or react with components of the active layer (7) and are degraded in the process. Functional element (5) according to one of the Claims 1 to 3 wherein the degradable spacers (14) are not spherical and are preferably rod-shaped. Functional element (5) according to one of the preceding claims, wherein the surface electrodes (12) contain at least one metal, a metal alloy or a transparent conductive oxide, preferably a transparent conductive oxide, and have a thickness of 10 nm to 2 µm. Functional element (5) according to one of the preceding claims, wherein the carrier films (13) contain at least one non-thermoplastic polymer, preferably contain polyethylene terephthalate. Functional element (5) according to one of the preceding claims, wherein each surface electrode (12) of the multilayer film (6) is electrically conductively contacted with at least one busbar and the surface electrodes (12) can be connected to an external voltage source via the busbars. Composite pane (100) with functional element (5) with electrically controllable optical properties according to one of the Claims 1 to 7th , at least comprising - an inner pane (1) comprising an inner side (III) and an outer side (IV) and an outer pane (2) comprising an inner side (II) and an outer side (I), - a thermoplastic intermediate layer (3), which the The inner side (III) of the inner pane (1) connects to the inner side (II) of the outer pane (2) and - the functional element (5) embedded in the thermoplastic intermediate layer (3) with electrically controllable optical properties. Composite pane (100) Claim 8 , wherein the thermoplastic intermediate layer (3) comprises at least one first thermoplastic composite film (4.1) and at least one second thermoplastic composite film (4.2) and optionally an edge seal (16), wherein the first thermoplastic composite film (4.1) the functional element (6) with the inside (III) connects the inner pane (1) and the second thermoplastic composite film (4.2) connects the functional element (6) to the inside (II) of the outer pane (2) and the optional edge seal (16) between the first thermoplastic composite film (4.1) and the second thermoplastic composite film (4.2) is arranged and surrounds the circumferential edge (8) of the functional element (5). Composite pane (1) Claim 8 or 9 wherein the composite pane (100) is a windshield or a motor vehicle roof pane, preferably a motor vehicle roof pane.

Images