Multilayer film with electrically controllable optical properties and at least one electrical contact area

Abstract

The invention relates to a multilayer film (1) with electrically controllable optical properties, comprising the following components in the indicated order in a face-to-face arrangement on top of one another: a) a first carrier film (5), b) a first planar electrode (3), c) an active layer or layer sequence (2) with electrically controllable optical properties, d) a second planar electrode (4) and e) a second carrier film (6), wherein in at least one contact region (B) the first carrier film (5), the first planar electrode (3) and the active layer or layer sequence (2) are removed so that the second planar electrode (4) is exposed, wherein the contact region (B) is designed in the form of a strip with a gradually tapering end.

Description

[0001] This invention relates to multilayer films with electro-controllable optical properties, methods for manufacturing the same, and composite glass plates comprising the same.

[0002] Mounting glasses with electrically switchable optical properties are known. Such mounting glasses contain functional elements, typically comprising an active layer or layer sequence between two planar electrodes. The optical properties of the active layer can be altered by applying a voltage to the planar electrodes. Examples of this are electrochromic functional elements, known for example from US 20120026573 A1, WO2010147494 A1, EP 1862849 A1, and WO 2012007334 A1. Another example is PDLC functional elements (…). Gather Liquid crystal dispersion ), which is known, for example, from DE 102008026339 A1. Another example is the SPD functional element ( suspended particles Device Such optical properties are known, for example, from EP 0876608 B1 and WO 2011033313 A1. The optical properties of the electrically controlled components are particularly light transmission (as in the case of electrochromic or SPD functional elements) or light scattering (as in the case of PDLC devices). The assembled glass with such functional elements can be suitably darkened electrically or equipped with high light scattering.

[0003] Electrically switchable functional elements are typically provided in the form of multilayer films. Here, the actual functional element is arranged between two polymer carrier films. This multilayer film simplifies the manufacture of electrically switchable assembly glass. Typically, multilayer films are laminated between two vitreous glass plates using conventional methods, resulting in a composite glass plate with electrically switchable optical properties. In particular, multilayer films are commercially available, so that assembly glass manufacturers do not need to specifically manufacture the switchable functional elements themselves.

[0004] Assembly glass with electro-controllable optical properties can be used, for example, as glass panels in vehicles, where its light transmission behavior can be electrically controlled. For example, they can be used as roof glass panels to reduce solar radiation or to reduce disruptive reflections. Such roof glass panels are known, for example, from DE 10043141 A1 and EP 3456913 A1. Windshield panels in which electrically controllable sun visors are achieved through switchable functional elements have also been proposed, replacing conventional mechanically folding sun visors in motor vehicles. Windshield panels with electrically controllable sun visors are known, for example, from DE 102013001334 A1, DE 102005049081 B3, DE102005007427 A1, and DE 102007027296 A1.

[0005] The carrier film is typically equipped with a conductive coating facing the active layer or layer sequence, which acts as planar electrodes. These planar electrodes must be electrically contacted to connect them to a voltage source. For this purpose, at least one region of each carrier film is typically removed along with the planar electrode adhered to it and the active layer (sequence) beneath it to expose the planar electrode on another carrier film, thereby providing a contact area. A bus, typically designed as a strip of copper film, can then be laid on this contact area and is itself connected to the voltage source via a cable.

[0006] To create the contact area, slits are traditionally made in the carrier membrane to separate the area to be removed from the surrounding area. These areas are typically in the shape of a busbar (sometimes slightly larger), designed as rectangular strips. The area separated in this way is then peeled off. A common problem here is that delamination occurs in the surrounding area of ​​the multilayer membrane due to the mechanical stress during the peeling process. This can adversely affect both the aesthetic appearance and electrical function of the multilayer membrane.

[0007] The object of this invention is to provide an improved method for producing such contact areas and a correspondingly processed multilayer film. This method should be easy and gentle to implement, thereby particularly avoiding delamination in the multilayer film area surrounding the contact area.

[0008] The object of the present invention is achieved by a multilayer film having electrocontrollable optical properties, the multilayer film comprising at least the following components stacked on top of each other in a planar manner in the order shown:

[0009] a) First carrier membrane,

[0010] b) First planar electrode,

[0011] c) An active layer or layer sequence with electro-controllable optical properties.

[0012] d) Second planar electrode and

[0013] e) Second carrier membrane.

[0014] According to the invention, a first carrier film, a first planar electrode, and an active layer or layer sequence are removed in at least one region of the multilayer film, referred to as a contact region, to expose a second planar electrode. According to the invention, the contact region is designed as a strip with a gradually tapering end.

[0015] The contact area of ​​the multilayer film is more precisely referred to as the contact area of ​​the second planar electrode within the meaning of this invention. It serves to make electrical contact with the second planar electrode for connection to an external voltage source. The first carrier film, the first planar electrode, and the active layer (sequence) are completely removed there. This exposes the second planar electrode, meaning it is no longer embedded within the multilayer film but is freely accessible. More precisely, the surface of the second planar electrode facing away from the second carrier film is freely accessible in the contact area, more precisely via the opening created by removing the first carrier film, the first planar electrode, and the active layer (sequence).

[0016] The object of the present invention is also achieved by a method for manufacturing a multilayer film with electrically switchable optical properties. Here, a multilayer film with electrically controllable optical properties is first provided (method step A), which includes at least the following components stacked facet to face in the order shown:

[0017] a) First carrier membrane,

[0018] b) First planar electrode,

[0019] c) An active layer or layer sequence with electro-controllable optical properties.

[0020] d) Second planar electrode and

[0021] e) Second carrier membrane.

[0022] Then, at least one region of the first carrier membrane is separated from the surrounding region of the first carrier membrane by an incision (method step B), wherein the incision surrounds a contact region in the form of a strip with a gradually tapering end. Then, starting from this end, said region of the first carrier membrane, together with the first planar electrode region to which it is adhered, is peeled off (method step C). Any remaining active layer or layer sequence is then removed from the second planar electrode.

[0023] The multilayer film and the method are described together below, wherein explanations and preferred embodiments also relate to the multilayer film and the method. If preferred features of the method are described, it means that the multilayer film is also preferably designed accordingly. Conversely, if preferred features of the multilayer film are described, it means that the method is also preferably implemented accordingly.

[0024] The inventors have surprisingly discovered that the shape of the contact area according to the invention, specifically the shape of the area exposing the second planar electrode after the removal of the first carrier film, the first planar electrode, and the active layer (sequence), produces significantly improved results. The first carrier film with the first planar electrode can be easily peeled off without delamination in the surrounding area, i.e., separation of the layers of the multilayer film. Conversely, in other shapes of the contact area, such as conventional rectangular or elliptical shapes, the degree of delamination is significantly greater, especially when the contact area is not adjacent to the side edge of the multilayer film in the edge region, but is separated from it by a distance or even located in the central region of the multilayer film. In this case, the delamination effect is particularly likely to occur due to the high mechanical load during the peeling of the first carrier film. Thus, new application areas or at least significantly simplified implementation are opened up by the multilayer film according to the invention. This is a major advantage of the invention.

[0025] The multilayer film is a stack of layers, wherein the layers in the stack include at least a first carrier film, a first planar electrode, an active layer or sequence of active layers, a second planar electrode, and a second carrier film, which are stacked on top of each other in a planar manner in the order shown. The layers of the stack are permanently and stably bonded to each other, for example, by adhesive bonding or lamination. Thus, the multilayer film is provided as a pre-laminated multilayer film, i.e., the carrier film, planar electrode, and active layer or sequence of layers have been bonded to form a multilayer film, and then contact areas are created by removing the area of ​​the first carrier film and the corresponding areas of the first planar electrode and the active layer (sequence). This type of multilayer film is generally commercially available and can be purchased, for example, from glass manufacturers, cut to the required size, and processed according to the invention. However, the multilayer film can also be manufactured by itself prior to processing.

[0026] According to the invention, the contact area, i.e., the exposed area of ​​the second planar electrode or the area where the first carrier film, the first planar electrode, and the active layer (sequence) are removed, is designed in a top view as a strip with gradually tapering ends. The strip should be understood herein as an elongated shape, the length of which is greater than its width, particularly at least twice the width, preferably at least three times, and especially preferably at least five times.

[0027] The contact area is defined by a contour line or boundary line. The cut produced in the first carrier film in the method according to the invention (method step B) extends along this boundary line. The cut is produced along (at least) a cutting line that (at least partially) coincides with the boundary line. If the contact area is directly adjacent to a side edge of the multilayer film, a section of the boundary line coincides with a section of the side edge. Of course, a cut is not necessary there. The cutting line then extends from the side edge back to the side edge of the multilayer film. Conversely, if the contact area is spaced apart from the side edge, the cutting line is circumferential and at least corresponds to the boundary line. In both cases, the cutting line can extend beyond the boundary line, thus creating further cuts that subsequently do not coincide with the boundary line of the contact area but remain as cuts adjacent to the contact area in the first carrier film. Cuts can be produced along a single cutting line corresponding to the boundary line (or, if the contact area is directly adjacent to a portion of the side edge of the multilayer film). However, cuts can also be produced along multiple touching or intersecting cutting lines.

[0028] The ends of the strip are understood as the regions in which the strip's length extends. The strip thus extends from one end to the other. The tapering ends are defined by two non-parallel segments of the boundary line of the contact area, which touch at a single point (the endpoint of the tapering region, the actual tip). Within the tapering ends (in other words, within the region of the tapering ends), the width of the strip continuously decreases until the endpoint.

[0029] In an advantageous embodiment, the strip-shaped contact area is designed to be symmetrical, more precisely, mirror-symmetrical with respect to a central axis in terms of length, such that the endpoints of the gradually tapering ends lie on this central axis. This is particularly suitable when the contact area is spaced a distance from the side edges of the multilayer film.

[0030] In a preferred embodiment, the contact area is designed in the shape of an elongated hexagon. Two opposing parallel sides of the hexagon form the lateral boundaries of the contact area in its extending direction (length dimension). The two endpoints of these two sides are connected to each other by two additional sides, which together form the gradually tapering ends of the contact area. The hexagon can be understood as a rectangle with two triangles connected to opposing side edges, where these triangles form the gradually tapering ends. The hexagonal shape achieves very good results in avoiding delamination. Furthermore, common buses (especially substantially rectangular strips of conductive films) are well-suited for this contact area because the shape of the central rectangular region of the hexagon (defined by the two opposing parallel boundaries extending in the length dimension) adapts to the shape of the bus. The hexagonal shape is particularly suitable due to the straight lateral boundary segments if the contact area is to be directly adjacent to the (typically straight) side edges of the multilayer film.

[0031] However, the contact area can also be achieved through other shapes. For example, it can be designed as a lens shape formed by two curves that touch twice. The two contact points of the curves form the endpoints of gradually tapering ends.

[0032] The implementation of the hexagonal and lens-shaped contact area is preferably mirror-symmetrical with respect to the central axis in terms of length. However, this is not absolutely necessary.

[0033] In another embodiment of the invention, the contact area is not mirror-symmetrical with respect to its central axis in terms of length. This is particularly suitable when the contact area is directly adjacent to the side edges of the multilayer film. In a preferred embodiment, the contact area is designed in a trapezoidal shape, particularly preferably an isosceles trapezoid. This trapezoid has two long sides (bases) and two short sides, which are arranged substantially parallel to each other and extend along the length of the strip-shaped contact area. The two long sides are of different lengths, with the longer of the two bases also referred to as the lower base of the trapezoid. The endpoints of the gradually tapering ends are the corners that connect the lower base to the two adjacent short sides. The trapezoidal shape is also well-suited for use with substantially rectangular strip-shaped busbars.

[0034] Another embodiment of the contact area that is not mirror-symmetrical relative to the central axis in length is the shape of a parallelogram. A parallelogram has two substantially parallel long sides and two substantially parallel short sides connecting the long sides. The endpoints, which taper to a point, are the end corners connecting a long side to an adjacent short side, where the angle between the long and short sides is less than 90°. In the case of a parallelogram, the two corners forming the endpoints are arranged on different long sides, while in the case of a trapezoid, they are arranged on the same long side (the lower base).

[0035] A trapezoidal shape is particularly preferred when the contact area is directly adjacent to and extends along the side edge of the multilayer film. Here, the lower base of the trapezoid coincides with a section of the side edge. The cutting line along which the slit is formed through the first carrier film does not include the lower base of the trapezoid, but instead begins at the side edge of the multilayer film, includes a first short side, a shorter long side, and a second short side, and returns to the side edge of the multilayer film. The endpoint of the gradually tapering end is located on the side edge of the multilayer film. A hexagonal shape is particularly preferred when the contact area is spaced a certain distance from the side edge of the multilayer film.

[0036] As described above, the gradually tapering end of the contact area is defined by two contact segments of the boundary line of the contact area. In an advantageous embodiment, these segments form an angle of less than 90°, preferably 50° to 90° (excluding 90°), particularly between 50° and 90°. This yields particularly good results.

[0037] In a preferred embodiment of the method, the tapering ends are each defined by two contact segments of the boundary line of the contact area, wherein a cut is introduced into the first carrier film at least in the extension of each of the segments. Thus, the cut line (or the cut segment at the end) continues beyond the contact point. After the first carrier film in the contact area is removed, a portion of these cut segments (up to the intersection) respectively forms a segment of the boundary line of the contact area. The portion of each cut segment beyond the intersection remains as a cut in (at least) the first carrier film. At each endpoint of the contact area, two cuts are thus introduced into the first carrier film, along which the carrier film is separated. These two cuts begin from the relevant endpoint of the contact area and form an extension of the segment of the boundary line of the contact area adjacent to the endpoint. It has been shown that this is particularly advantageous for gently separating and removing the first carrier film in the contact area and avoiding delamination. The length of the cut (from the endpoint of the tapering end or from the intersection of the cut segments) is preferably at least 1 mm, particularly preferably 1 mm to 5 mm, and very particularly preferably 1.5 mm to 3 mm. By using a cut length within this range, the first carrier film in the contact area is removed gently, and the cut is not too visually noticeable. Of course, when the cut line is located on the side edge of the multilayer film, such as in the case of a trapezoid where the bottom edge coincides with the side edge, a cut line extending beyond the endpoint of the gradually tapering end region is not used.

[0038] Preferably, in the contact area having an exposed second planar electrode, a busbar (busbar, bus) is arranged on and conductively connected to the second planar electrode. The busbar can be simply placed, soldered to the planar electrode, or connected to the planar electrode via a conductive adhesive. Alternatively, the busbar can be inserted into the contact area such that the area of ​​the busbar extends beneath the surrounding first carrier film, thereby securing the busbar.

[0039] The busbar is used for electrical contact with the planar electrode. It is configured to connect to a voltage source via a cable to apply a potential to the planar electrode. It is preferably designed as a strip of conductive film, such as a strip of copper film. The width of the busbar is preferably from 1 mm to 10 mm, for example, about 5 mm. The thickness of the busbar is preferably from 50 μm to 200 μm, for example, about 90 μm.

[0040] To ensure the functionality of the electrically controllable multilayer film, electrical contact with the first planar electrode is also necessary. In principle, it is conceivable that only the second planar electrode is contacted in the contact area designed according to the invention, while the first planar electrode is contacted in a conventional manner. However, the multilayer film preferably also has a contact area according to the invention for the first planar electrode. The multilayer film then has at least one additional contact area in which the second carrier film, the second planar electrode, and the active layer or layer sequence are removed to expose the first planar electrode. This additional area (the contact area of ​​the first planar electrode) is designed as a strip with a gradually tapering end when viewed from above, just like the contact area of ​​the second planar electrode.

[0041] The foregoing statements regarding the contact area of ​​the second planar electrode according to the invention also apply independently to the contact area of ​​the first planar electrode, if it is also designed according to the invention. Preferably, the at least one contact area of ​​the first planar electrode is designed to be the same as the at least one contact area of ​​the second planar electrode.

[0042] In one embodiment of the invention, the contact area is directly adjacent to and extends parallel to the side edge of the multilayer film (i.e., the length dimension of the contact area is arranged substantially parallel to the side edge). Conversely, in a particularly advantageous embodiment, the contact area is spaced apart from the side edge of the multilayer film such that it is completely surrounded by the rest of the multilayer film. In this embodiment, the contact area also preferably extends parallel to the side edge. Because the area of ​​the carrier film to be removed is completely surrounded by the other areas of the carrier film, a particularly strong mechanical load occurs during removal and a delamination effect is particularly likely. The design of the contact area according to the invention, which reduces the possibility of such a delamination effect, has a particularly positive effect here. The multilayer film may also have multiple contact areas, some of which are directly adjacent to the side edge, while others are spaced apart from it. If the contact area is spaced apart from the side edge, it can be arranged at a small distance of a few millimeters or centimeters in the edge region. However, it may also have a large distance from the side edge, for example, extending substantially centrally between two opposing side edges, to accelerate the switching behavior of the multilayer film.

[0043] In a particularly preferred embodiment, a plurality of contact regions for the second planar electrode and contact regions for the first planar electrode are arranged sequentially along a line. The length dimensions of the contact regions are arranged along this line, and the contact regions are arranged in such a way that the contact regions for the second planar electrode and the contact regions for the first planar electrode alternate. This results in a seemingly tortuous electrical contact, wherein the busbars of the second planar electrode and the busbars of the first planar electrode are arranged sequentially in a linear manner, alternating. This allows for faster switching behavior when optical properties change. This is particularly advantageous in the case of electrochromic multilayer films, as they typically tend to have relatively slow switching behavior. The line is preferably arranged parallel to at least one side edge of the multilayer film. The line is particularly preferably a loop extending along the entire side edge of the multilayer film in the edge region. A distance of several millimeters to 1 cm can be provided between adjacent contact regions. The contact regions on the line can be directly adjacent to or spaced apart from the side edge of the multilayer film. The length of each contact region is preferably 2.5 cm to 10 cm, and the width is preferably 3 mm to 10 mm.

[0044] The active layer or layer sequence has variable optical properties, which can be controlled by a voltage applied to the active layer via a planar electrode. The optical properties of the active layer or layer sequence can be controlled by applying a voltage to the planar electrode or by changing the voltage located on the planar electrode. Variable optical properties particularly relate to the degree of light transmission and / or light scattering, wherein in the context of this invention, light is understood to refer particularly to visible light in the spectral range of 380 nm to 780 nm. In the context of this invention, electrically controllable optical properties are understood to refer particularly to those properties that can be steplessly controlled. In the context of this invention, the switching state of the multilayer film represents the degree of change in optical properties relative to a voltage-free state. A 0% switching state corresponds to a voltage-free state, and a 100% switching state corresponds to the maximum change in optical properties. All switching states can be achieved steplessly between them by appropriate voltage selection. For example, a 20% switching state corresponds to 20% of the maximum change in optical properties. The optical properties particularly relate to light transmission and / or scattering behavior. However, it is also conceivable in principle that electrically controllable optical properties can only be switched between two discrete states. At this point, there are only two switching states: 0% and 100%. It can also be envisioned that the electro-controllable optical performance can switch between more than two discrete states.

[0045] Two planar electrodes and the active layer or layer sequence therebetween form the actual electrically controllable functional element of the multilayer film according to the invention, which is protected and stabilized by a carrier film. In principle, the functional element can be any functional element with electrically controllable optical properties known to those skilled in the art. The design of the active layer or layer sequence depends on the type of functional element.

[0046] In a particularly preferred embodiment, the multilayer film according to the invention is an electrochromic multilayer film, and the functional element is an electrochromic functional element. The electrochromic functional element comprises an active layer sequence (electrochromic layer sequence) between planar electrodes. Therefore, the active layer or layer sequence according to the invention is an electrochromic active layer sequence. This active layer sequence comprises the following components stacked on top of each other in planar form in the order shown:

[0047] - Ion storage layer,

[0048] - Electrolyte layer, and

[0049] - Electrochromic layer.

[0050] Electrochromic layers are practical carriers of electrochemically controllable optical properties. They are electrochemically active layers whose light transmission depends on the degree of ion intercalation. Ions (e.g., H+) + Li + Na + or K + Ions are stored in and supplied by an ion storage layer. An electrolyte layer spatially separates the electrochromic layer from the ion storage layer and facilitates ion migration. If a DC voltage of suitable polarity is applied to a planar electrode, ions migrate from the ion storage layer through the electrolyte layer to the electrochromic layer, thus altering the optical properties (color, light transmission) of the electrochromic layer according to the degree of ion migration. If a DC voltage of opposite polarity is applied to the planar electrode, ions migrate from the electrochromic layer back to the ion storage layer through the electrolyte layer, and the optical properties of the electrochromic layer change in the opposite manner. If no voltage is applied to the planar electrode, the current state remains stable. Suitable electrochromic layers contain electrochromic materials such as inorganic oxides (e.g., tungsten oxide or vanadium oxide), complex compounds (e.g., Prussian blue), or conductive polymers (e.g., 3,4-poly(ethylenedioxythiophene) (PEDOT) or polyaniline). Electrochromic functional elements are known, for example, from WO 2012007334 A1, US 20120026573 A1, WO 2010147494 A1, and EP1862849 A1. The electrolyte layer is typically designed as a film of organic or inorganic electrically insulating material with high ionic conductivity, such as lithium phosphorus oxynitride. The ion storage layer is either permanently transparent (pure ion storage layer) or has electrochromic behavior opposite to that of the electrochromic layer. Examples of pure ion storage layers are layers containing mixed oxides of titanium and cerium, and examples of anodic electrochromic ion storage layers are layers containing iridium oxide or nickel oxide.

[0051] It has been shown that electrochromic multilayer films are particularly susceptible to delamination effects when the carrier film is locally removed to create a contact area. Therefore, the method according to the invention, in which the carrier film is removed gently so that delamination can be avoided, is particularly advantageous in the case of electrochromic multilayer films.

[0052] However, the present invention can also be applied to other multilayer films, such as PDLC multilayer films or SPD multilayer films.

[0053] In the case of PDLC multilayer films, the functional element is the PDLC functional element ( Polymer Dispersed Liquid Crystal PDLC functional elements comprise an active layer between planar electrodes. The active layer or layer sequence according to the invention is therefore designed herein as an active layer. The active layer is a PDLC layer and contains liquid crystals embedded in a polymer matrix. PDLC functional elements typically operate using an alternating current voltage. If no voltage is applied to the planar electrodes, the liquid crystals align in a disordered manner, resulting in strong scattering of light passing through the active layer. If a voltage is applied to the planar electrodes, the liquid crystals align in a common direction, and the transmission of light through the active layer increases. Such functional elements are known, for example, from DE 102008026339 A1. In the context of this invention, the term PDLC should be interpreted broadly and include related functional elements based on liquid crystal alignment, such as PNLC functional elements (…). Polymer Network liquid crystal ).

[0054] In the case of SPD multilayer films, the functional element is the SPD functional element ( Suspended Particle Device The SPD functional element comprises an active layer between planar electrodes. The active layer contains suspended particles, preferably embedded in a viscous matrix. The absorption of light by the active layer can be altered by applying a voltage to the planar electrodes, resulting in a change in the positioning of the suspended particles. Such functional elements are known, for example, from EP 0876608 B1 and WO 2011033313 A1.

[0055] Planar electrodes are configured for electrical connection to at least one external voltage source. Planar electrodes are preferably transparent, which in the context of this invention means that they have at least 50%, preferably at least 70%, and particularly preferably at least 80% light transmittance in the visible spectrum. Planar electrodes are in particular conductive thin films or stacks of thin films. Planar electrodes preferably contain at least one metal, metal alloy, or transparent conductive oxide (TCO). Planar electrodes particularly preferably contain at least one transparent conductive oxide. Planar electrodes may be based, for example, on 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, preferably based on silver or ITO, especially ITO. Planar electrodes preferably have a thickness of 10 nm to 2 μm, particularly preferably 20 nm to 1 μm, very particularly preferably 30 nm to 500 nm, and especially 50 nm to 200 nm. If the thin layer is formed based on a material, then in the context of this invention this means that the layer is mainly composed of that material (more than 50% by weight, preferably more than 90% by weight, particularly more than 99% by weight), wherein the layer may contain small amounts of other materials, such as dopants.

[0056] The carrier film preferably comprises or is formed based on at least one thermoplastic polymer, particularly preferably polyethylene terephthalate (PET), polypropylene, polyvinyl chloride, fluorinated ethylene-propylene, polyvinyl fluoride, or ethylene-tetrafluoroethylene, with PET being very particularly preferred. This is particularly advantageous for the stability of the multilayer film. The thickness of each carrier film is preferably 0.1 mm to 1 mm, particularly preferably 0.1 mm to 0.5 mm, and especially 0.1 mm to 0.2 mm. On the one hand, the small thickness of the mounting glass into which the multilayer film should be inserted is advantageously achieved by the carrier film having such a small thickness. On the other hand, effective protection of the active layer and the conductive layer is ensured. If the polymer layer is formed based on a material, then in the context of this invention, this means that the layer is mainly composed of that material (more than 50% by weight), wherein the layer may contain other materials, such as plasticizers, stabilizers, or UV blockers.

[0057] Typically, polymer films with a conductive coating are used, where the coating forms the associated planar electrode. PET films coated with ITO are particularly common. Therefore, the adhesion between the carrier film and the planar electrode is very strong, which is advantageous for the method according to the invention, because the planar electrode remains adhered and is removed along with the carrier film during the removal of the carrier film area (method step C). By introducing cuts not only in the carrier film but also in the planar electrode in method step B, clean and simple removal of the planar electrode from the contact area can be facilitated.

[0058] In method step (B), slits are introduced in the first carrier film to remove it in the contact area. Preferably, slits are introduced not only in the first carrier film but also in the first planar electrode. The area of ​​the first carrier film and the area of ​​the first planar electrode to which it is adhered can then be cleanly removed together. Optionally, the slits may also extend into the active layer or layer sequence.

[0059] In an advantageous embodiment of the method according to the invention, a cut is generated in step (B) by radiation from a laser. Laser processing can be performed faster and more gently than, for example, machining, such as cutting with a blade. The inventors have discovered that if the area of ​​the carrier film to be removed is separated from the surrounding area by laser cutting, the carrier film in the contact area can be removed very simply and gently without causing a delamination effect.

[0060] Radiation from a laser is directed at the multilayer film, with the first carrier film to be cut preferably facing the laser. It irradiates the first carrier film to cut it. For this purpose, radiation from the laser moves along one or more cutting lines. The cutting lines (or the sum of all cutting lines) correspond to the boundary line (outline) of the contact area to be created, i.e., the area of ​​the first carrier film to be removed – except that the contact area should be designed to adjoin the side edges of the multilayer film so that a portion of the boundary line coincides with a portion of the side edge and no cutting line is needed. Alternatively, the cutting lines include the boundary line but extend beyond it. This is particularly suitable for cases where a cut should be introduced in the carrier film at a gradually tapering end that continues beyond the contact area.

[0061] Radiation from the laser is preferably focused onto the multilayer film, particularly onto the (first) carrier film facing the laser, by at least one optical element, such as a lens or objective lens. f-θ lenses or f-θ objectives are particularly suitable. They cause the focal points of the radiation from the laser to be arranged in a plane at different exit angles, and achieve a constant velocity of movement of the radiation from the laser over the multilayer film.

[0062] The focal length of the focusing element determines the range of the focal point of the radiation from the laser. The focal length of the focusing optics is preferably 2 cm to 20 cm, and particularly preferably 3 cm to 5 cm. This yields exceptionally good results. Smaller focal lengths require excessively small working distances between the multilayer film and the optics. Larger focal lengths result in an excessively large laser focal point, thus limiting the resolution of the cutting process and the power density within the focal point.

[0063] If the area of ​​the second carrier film should also be removed to create the contact area according to the invention for the first planar electrode, the method is repeated, wherein the second carrier film is oriented accordingly toward the laser and the radiation from the laser is focused onto the second carrier film.

[0064] Between the laser and the focusing optics, radiation from the laser can be conducted through at least one optical waveguide, such as a glass fiber. Other optical elements can also be arranged in the laser beam path, such as collimators, apertures, filters, or elements for frequency doubling.

[0065] A notch is created by moving radiation from the laser relative to the multilayer film. In an advantageous embodiment, the multilayer film is fixed in position and the radiation from the laser moves above the carrier film. The radiation from the laser is preferably moved by at least one mirror connected to a movable component. The mirror can be tilted in two directions, preferably two orthogonal directions, particularly horizontally and vertically, via the movable component. The movement of the radiation from the laser can also be achieved by multiple mirrors, each connected to a movable component. For example, the movement of the radiation from the laser can be achieved by two mirrors, one tilted horizontally and the other tilted vertically. Alternatively, the movement of the radiation from the laser can be achieved by moving a focusing element and the laser, or by moving a focusing element and an optical waveguide, above the fixed multilayer film. Alternatively, the radiation from the laser can be fixed in position and the multilayer film can be moved to introduce an insulating wire.

[0066] The wavelength of the radiation from the laser should be selected such that the carrier film has sufficiently high absorption of the radiation from the laser. By focusing the radiation from the laser onto the first carrier film and / or by appropriately selecting the laser power, it is possible to prevent cutting not only of the (first) carrier film facing the laser but also of the (second) carrier film facing away from the laser.

[0067] The wavelength is preferably in the mid-infrared (IR) range of 3 μm to 50 μm, particularly preferably 5 μm to 20 μm, and very particularly preferably 8 μm to 15 μm. Therefore, good results are achieved with common carrier films, especially those made of PET. In an advantageous embodiment, a CO2 laser with a wavelength of 10.6 μm is used. However, other types of lasers can also be used in principle, such as solid-state lasers with a suitable crystal or diode as the active medium.

[0068] The output power of the radiation from the laser is preferably from 1W to 50W, particularly preferably from 5W to 20W, and especially from 8W to 12W. The required output power depends in particular on the wavelength of the radiation from the laser and the degree of absorption of the carrier film, and can be determined by those skilled in the art through simple experiments. Good results have been achieved with common carrier films at the power range described above.

[0069] The radiation from the laser preferably travels over the multilayer film at a speed of 0.5 m / s to 20 m / s, particularly preferably 1 m / s to 10 m / s, and very particularly preferably 3 m / s to 5 m / s. This is advantageous for time-saving processing when the first carrier film is completely separated.

[0070] In a preferred embodiment, the laser operates in a pulsed manner. This is particularly advantageous for high power density and efficient incision introduction. The pulse frequency is preferably from 100 Hz to 10000 Hz, particularly preferably from 500 Hz to 5000 Hz, and very particularly preferably from 1000 Hz to 3000 Hz. This is particularly advantageous for the power density of the laser during laser structuring. The pulse length is preferably in the microsecond range and, for example, from 10 μs to 100 μs.

[0071] After the carrier membrane is cut, in method step (C), the excised area of ​​the first carrier membrane is removed together with the corresponding area of ​​the first planar electrode. For this purpose, one of the two gradually tapering ends of the strip-shaped area is lifted, and the area of ​​the first carrier membrane is peeled off starting from that end. A thin blade, such as a razor blade, is preferably used for this.

[0072] When peeling off the area of ​​the first carrier film, it is possible that a portion of the active layer or layer sequence remains adhered to the first carrier film and is removed along with it. However, if not the entire active layer or layer sequence, at least a portion of the active layer or layer sequence is typically retained in the multilayer film. To expose the second planar electrode, in this case, it is necessary to remove any residual active layer or layer sequence from the second planar electrode in the contact area during method step (D).

[0073] The residual active layer or layer sequence is preferably removed using an organic solvent. Ethanol, acetone, or isopropanol are particularly preferred. Surfactants can be added to the organic solvent. It has been shown that good results can be achieved using commercially available glass cleaners, grease solvents, or industrial surface cleaners.

[0074] Particularly advantageous is that the solvent is applied to the contact area and can act there to detach the residual active layer or layer sequence from the second planar electrode. The action time is preferably at least 1 second, particularly preferably at least 2 seconds, for example from 1 second to 60 seconds, and very particularly preferably from 2 seconds to 10 seconds. The solvent can then be simply wiped away along with the residual active layer (sequence), preferably using a lint-free cloth, which is also used, for example, for cleaning eyeglasses or other lenses.

[0075] In a preferred embodiment, after cleaning the second planar electrode, a busbar is applied to it and connected to it in a conductive manner, such as by placement, gluing, or soldering.

[0076] After the contact area according to the invention is generated, preferably in another method step, the busbar is conductively positioned on the now exposed second planar electrode.

[0077] If a contact area according to the invention is also required for the first planar electrode, the method is performed accordingly, wherein the second carrier film is cut and partially removed. The statements made so far apply accordingly. The busbar is then preferably also disposed on the first planar electrode.

[0078] This can be achieved, for example, by melting the carrier film or by using (preferably a polymer) to seal the side edges of the multilayer film. This protects the active layer, particularly preventing components (especially plasticizers) from diffusing into the active layer of the composite glass plate in which the multilayer film is embedded, which could lead to deterioration of the functional elements.

[0079] In addition to the active layer or layer sequence, planar electrode and carrier film, multilayer films can of course have other layers known in themselves, such as barrier layers, blocking layers, anti-reflective or reflective layers, protective layers and / or smoothing layers.

[0080] The invention also includes the use of the multilayer film according to the invention in assembled glass, particularly in composite glass panels, in buildings, such as in entrance or window areas, or in land, sea and air transportation vehicles, particularly in trains, ships, airplanes and motor vehicles, for example as windshield panels, rear glass panels, side glass panels and / or roof glass panels.

[0081] The invention also includes a composite glass plate, wherein at least one multilayer film according to the invention is arranged in a facet manner between two glass plates. The multilayer film is preferably embedded in an intermediate layer of the composite glass plate. For this purpose, each carrier film is preferably bonded to one of the glass plates by at least one thermoplastic bonding film. The thermoplastic bonding film comprises at least one thermoplastic polymer, such as ethylene vinyl acetate (EVA), polyvinyl butyral (PVB), or polyurethane (PU), particularly preferably PVB. The thickness of the thermoplastic bonding film is preferably from 0.25 mm to 2 mm, for example, a standard thickness of 0.38 mm or 0.76 mm. Preferably, the two bonding films protrude around the multilayer film on both sides. The side edges of the multilayer film are particularly preferably surrounded in a frame-like third thermoplastic bonding film in a circumferential manner. It has a notch into which the multilayer film is embedded.

[0082] The glass plate is preferably made of glass, particularly soda-lime glass, or of rigid, clear plastic such as polycarbonate (PC) or polymethyl methacrylate (PMMA). The glass plate can be clear and transparent, or it can be colored or tinted. The thickness of the glass plate can vary widely to suit various requirements. The thickness of each glass plate is preferably from 0.5 mm to 15 mm, more preferably from 1 mm to 5 mm. The composite glass plate can have any three-dimensional shape. The composite glass plate is preferably flat or slightly or strongly curved in one or more directions in space.

[0083] The composite glass plate can be manufactured by stacking and laminating at least a first glass plate, a first thermoplastic bonding film, a multilayer film with electro-optically controllable properties according to the invention, a second thermoplastic bonding film, and a second glass plate in the order shown to produce the composite glass plate. Methods known per se can be used for this purpose, such as autoclave method, vacuum bag method, vacuum ring method, calendering method, vacuum laminator, or combinations thereof. Bonding of the glass plates through the intermediate layer (made of the thermoplastic bonding film and the multilayer film) is generally carried out under the influence of heat, vacuum, and / or pressure.

[0084] The invention will be explained in more detail with reference to the accompanying drawings and embodiments. The drawings are schematic and not to scale. The drawings do not limit the invention in any way. They show:

[0085] Figure 1 A top view of one embodiment of the multilayer film according to the present invention.

[0086] Figure 2 Crossing along X-X' according to Figure 1 The cross-section of the multilayer membrane,

[0087] Figure 3 A top view of another embodiment of the multilayer film according to the present invention.

[0088] Figure 4 Top views of various embodiments of the invention, showing the cutting lines in the first carrier film and the resulting contact areas.

[0089] Figure 5 Top views of various non-inventive embodiments of the first carrier film as a comparative example, showing the cutting lines and the resulting contact areas.

[0090] Figure 6 The cross-section passing through the multilayer membrane at various time points according to the method of the present invention,

[0091] Figure 7 A cross section passing through the composite glass plate containing the multilayer film according to the invention.

[0092] Figure 8A top view of another embodiment of the multilayer film according to the present invention, and

[0093] Figure 9 A top view of another embodiment of the multilayer film according to the present invention.

[0094] Figure 1 and Figure 2 Details of a multilayer film 1 with electro-controllable optical properties according to the present invention are shown. The multilayer film 1 is an electrochromic multilayer film that can switch from a transparent, uncolored state to a colored state with reduced light transmission.

[0095] The multilayer film 1 is defined by a first carrier film 5 and a second carrier film 6. The carrier films 5 and 6 are composed of PET and have a thickness of, for example, 0.125 mm. The carrier films 5 and 6 are equipped with an ITO coating of approximately 100 nm thickness, which forms the first planar electrode 3 and the second planar electrode 4. An active layer sequence 2 is disposed between the planar electrodes 3 and 4. The layer sequence 2 is an electrochromic layer sequence and consists of an ion storage layer 2a, an electrolyte layer 2b, and an electrochromic layer 2c. By applying a DC voltage to the planar electrodes 3 and 4, ions can be excited to migrate from the ion storage layer 2a through the electrolyte layer 2b to the electrochromic layer 2c, and vice versa. The ion ratio in the electrochromic layer 2c determines its optical properties, particularly the light transmittance and color.

[0096] Planar electrodes 3 and 4 are electrically contacted in the surrounding edge region. Contact regions B and B' are alternately arranged along the surrounding edge region and adjacent to the side edges of the multilayer film 1. Contact region B is used for electrical contact with the second planar electrode 4. There, the first carrier film 5, the first planar electrode 3, and the active layer sequence 2 are completely removed, thereby exposing the second planar electrode 4. Bus 7.2 is arranged on the second planar electrode 4. Contact region B' is used for electrical contact with the first planar electrode 3. There, the second carrier film 6, the second planar electrode 4, and the active layer sequence 2 are completely removed, thereby exposing the first planar electrode 3. Bus 7.1 is arranged on the first planar electrode 3. Planar electrodes 7.1 and 7.2 are designed as strips of tin-plated copper film with a thickness of approximately 0.06 mm. The planar electrodes are configured for connection to a DC voltage source via cables, wherein bus 7.1 is connected to one terminal of the voltage source, and bus 7.2 is connected to the other terminal of the voltage source.

[0097] Each contact region B has its own busbar 7.2. Similarly, each contact region B' has its own busbar 7.1. Along the surrounding edge region, the two planar electrodes 3 and 4 are thus alternately electrically contacted in a zigzag manner. The electrochromic multilayer film 1 has a relatively slow switching behavior. Through this zigzag electrical contact, a faster change in optical performance can be achieved compared to, for example, the first planar electrode 3 being contacted only along one side edge and the second planar electrode 4 being contacted along the opposite side edge.

[0098] The strip-shaped contact areas B and B' are designed in the shape of slender hexagons and extend along their adjacent side edges.

[0099] Figure 3 Another embodiment of the multilayer film 1 according to the present invention is shown. (Compared to...) Figure 1 Unlike other solutions, contact areas B and B' are designed in the shape of isosceles trapezoids. They also adjoin the side edges of the multilayer film 1, with the longer of the two base sides (the lower base side) coinciding with the side edges. This implementation, when the contact areas adjoin the side edges of the multilayer film 1, is relatively... Figure 1 This is the preferred implementation method because it saves more space.

[0100] Figure 4 Various embodiments of the contact region B and the cutting line S according to the invention are shown, the cutting line being introduced into the first carrier film 5 for removal. According to the invention, the contact region B is designed as a strip with a gradually tapering end, which can be achieved in different types and ways.

[0101] According to Figure 4 In one implementation, the contact area B is designed in the shape of an elongated hexagon. A cutting line S surrounds and encloses the contact area B, corresponding to the boundary line of the contact area B. The hexagonal shape is advantageous because it provides a substantially rectangular area between the gradually tapering ends, which is well-suited for inserting a (typically rectangular strip-shaped) busbar 7.2 into the contact area B.

[0102] The gradually tapering ends of the contact area B are formed by two segments of the cutting line S that touch at a single point, i.e., at the endpoints of the gradually tapering ends. These segments of the cutting line S form an angle α, which is preferably less than 90°.

[0103] According to Figure 4 In embodiment b, the contact area B is also designed as an elongated hexagonal shape. A cutting line S surrounds and encloses the contact area B. It includes the boundary line of the contact area B but continues beyond the endpoints of the gradually tapering ends. Thus, the first carrier film 5 in the contact area B can also be more easily lifted and peeled off.

[0104] The gradually tapering ends of the contact area B are formed by two segments of the cutting line S that intersect at a single point, i.e., at the endpoints of the gradually tapering ends. Each of the two segments of the cutting line S continues beyond its endpoint in the extension of the relevant segment of the boundary line of the contact area B.

[0105] According to Figure 4 In embodiment c, the contact area B is designed to be lens-shaped. Here, the cutting line S also extends beyond the gradually tapering end of the segment of the boundary line of the contact area B adjacent to the endpoint. Since the cutting line is curved, the tangent at the endpoint (intersection) is used to determine the angle α.

[0106] According to Figure 4 In implementation scheme d, the contact area B is designed to be trapezoidal in shape. According to... Figure 4 In one embodiment of e, the contact area B is designed in the shape of a parallelogram. In these embodiments, if the endpoint is not located on the side edge of the multilayer film 1, the cutting line S may also extend beyond the endpoint of the gradually tapering end.

[0107] The cut line shown illustrates the principle of the invention. If the contact area B is directly adjacent to the side edge of the multilayer film 1, such that a section of the boundary line of the contact area B coincides with a section of the side edge, then a cut line is naturally not needed in that section. Here, a shape with straight side boundaries is preferred, for example... Figure 4 The hexagonal shapes of a, 4b, 4d, and 4e. In particular, one of the side boundaries (the long side of the hexagon, trapezoid, or parallelogram) coincides with a segment of the side edge of the multilayer film 1 and does not need to be cut.

[0108] Figure 5 Various embodiments of the contact area B and the cutting line S, not according to the invention, are shown as comparative examples. They are not designed as strips with tapered ends.

[0109] According to Figure 5 In implementation a, the contact area B is designed to be rectangular. A cutting line S surrounds and encloses the contact area B, corresponding to the boundary line of the contact area B.

[0110] According to Figure 5 In embodiment b, the contact area B is also designed to be rectangular. The cutting line S extends beyond each corner in the extensions of the two adjacent sides.

[0111] According to Figure 5 In implementation c, the contact area B is designed as an elongated octagonal shape. According to... Figure 5 In implementation d, the contact area B is designed to be elliptical. According to... Figure 5In implementation e, the contact area B is designed as a rectangle with rounded corners. According to... Figure 5 In the implementation of f, the contact area B is designed to be oval in shape, which can be interpreted as a rectangle with two semicircles attached to opposite short sides.

[0112] Figure 6 The process of manufacturing contact region B at various time points is shown. Figure 1 The cross-section of the multilayer film 1. First, the multilayer film 1 ( Figure 6 a). This typically involves cutting a commercially available multilayer film to the size required for the application. A cut S' is then introduced into the first carrier film 5 (along the cut line S) to separate the area to be removed from the first carrier film 5, which has the shape of the contact area B, from the surrounding area of ​​the first carrier film 5. Figure 6 b). As shown in the figure, the cut S' can also optionally extend through the first planar electrode 3.

[0113] The cut S' is preferably generated by radiation from a laser, which is focused on the first carrier film 5 and moved along the cutting line S above the multilayer film 1 by a laser scanner. For this purpose, a pulsed CO2 laser with a wavelength of 10.6 μm can be used, for example.

[0114] After the area of ​​the first carrier film 5 located in the designed contact area B is separated from the rest of the carrier film 5 by the surrounding cut S', it is removed together with the area of ​​the first planar electrode 3 to which it is adhered. Figure 6 c). For this purpose, for example, one of the tapering ends is lifted with a razor blade, and the area of ​​the first carrier membrane 5 is peeled off from there.

[0115] It is possible that a portion of the active layer sequence 2 may also remain adhered to the removed area of ​​the first carrier film 5. However, if not the entire active layer sequence 2, at least some residual active layer sequence 2 is typically retained in the multilayer film 1 (as shown). The residual active layer sequence 2 now needs to be removed from the second planar electrode 4 in the contact area. Figure 6 d). This is preferably done by applying an organic solvent, such as ethanol, to the contact area b and allowing it to act. The organic solvent can then be simply wiped away along with any remaining layer sequence 2 with a lint-free cloth. The second planar electrode 4 is now exposed in the contact area B, and the bus 7.2 can be disposed thereon in a conductive manner, which is not shown. Commercially available grease-removing solvents or surface cleaners, such as Loctite 7840, can also be used for cleaning.

[0116] It also creates a contact region B' for the first planar electrode, wherein a cut is introduced into the second carrier film 6, rather than the first carrier film 5.

[0117] Figure 7 It shows passing through with from Figure 1 The cross-section of the composite glass panel according to the multilayer film 1 of the present invention is shown. The composite glass panel is used, for example, as the roof glass panel of a passenger vehicle, where light transmission can be locally electrically controlled. The composite glass panel includes a first glass panel 12 (outer glass panel) and a second glass panel 13 (inner glass panel), which are bonded together by an intermediate layer. The first glass panel 12 and the second glass panel 13 are composed of soda-lime glass, which may optionally be colored. For example, the thickness of the first glass panel 12 is 2.1 mm, and the thickness of the second glass panel 13 is 1.6 mm.

[0118] The intermediate layer comprises three thermoplastic layers 14a, 14b, and 14c, each formed of a 0.38 mm thick PVB thermoplastic film. The first thermoplastic layer 14a is bonded to the first glass plate 12, and the second thermoplastic layer 14b is bonded to the second glass plate 13. The third thermoplastic layer 14c, located between these layers, has a notch into which the multilayer film 1, with its electro-optically controllable properties, is substantially precisely fitted, i.e., flush with all sides. The third thermoplastic layer 14c thus appears to form a frame or framework for the approximately 0.3 mm thick multilayer film 1, which thickens to approximately 0.4 mm in the edge regions via busbars 7.1 and 7.2 for electrical contact. The multilayer film 1 is thus completely encapsulated in the thermoplastic material and is therefore protected.

[0119] The composite glass panel has a surrounding edge area equipped with an opaque overprint 15. This overprint 15 is typically formed of black enamel. It is printed and fired into the glass panel surface in a screen printing method as a printing ink containing black pigment and glass frit. The overprint 15 is applied, for example, to the inner surface of the first glass panel 12 and also to the inner surface of the second glass panel 13. The side edges and contact areas B, B' of the multilayer film 1 are covered by this overprint 15.

[0120] Figure 8 A top view of another embodiment of the multilayer film 1 according to the invention is shown. It has two contact regions B' for a first planar electrode 3, which extend substantially along two opposing side edges of the multilayer film 1. Furthermore, there is a contact region B for a second planar electrode 4, which extends parallel to it and is disposed centrally between the two contact regions B' (“center conductor”). The contact regions B are spaced apart from the side edges of the multilayer film 1. A particular advantage of the invention is that such contact regions can be achieved without delamination during removal of the carrier film.

[0121] The connection design shown is for illustrative purposes only. In principle, any connection design can be implemented. For example, from... Figure 8The single contact areas B, B' can be replaced by multiple contact areas B, B' arranged alternately and linearly. This implementation is shown in Figure 9 The contact regions B and B' that are directly adjacent to the side edges of the multilayer film 1 are designed in a trapezoidal shape. Here, the lower base of the trapezoid, along with the gradually tapering endpoints, is arranged on the side edges of the multilayer film 1. The contact regions B and B' (“center conductors”) that are spaced a certain distance from the side edges of the multilayer film 1 are designed in an elongated hexagonal shape. This configuration has proven to be particularly advantageous.

[0122] Similarly, alternatively, such as... Figure 1 The zigzag contact in the middle also has a contact line extending in the center between two opposite side edges, which is preferably also achieved by a plurality of alternating and linearly arranged contact areas B, B'.

[0123] Example

[0124] Contact regions B of various shapes are formed in the electrochromic multilayer film 1. These contact regions B are not arranged adjacent to the side edges of the multilayer film 1, but rather spaced apart from them. This situation is particularly challenging because, due to the fact that the area of ​​the first carrier film 5 to be removed is completely surrounded by the remaining area of ​​the carrier film 5, particularly strong forces are applied during removal, and the risk of delamination is particularly high.

[0125] The cut S' is introduced into the first carrier film 5 by radiation from a CO2 laser with an emission wavelength of 10.6 μm and a power of approximately 11 W. The laser operates in a pulsed manner, with a pulse frequency of 2000 Hz and a pulse length of 10 µs to 100 µs. The radiation from the laser travels along the cutting line at a speed of 4 m / s.

[0126] The area of ​​the first carrier film 5 separated by the cutting line S is then peeled off with a razor blade, starting from the gradually tapering end. The results are then visually evaluated, and a positive result is given if the area of ​​the first carrier film 5 to be removed is completely separated and can be easily removed, and if there is no delamination of the multilayer film 1 due to peeling (particularly separation between layers in the area surrounding the contact area B).

[0127] The shape of contact area B and the percentage of positive results for the examples and comparative examples are shown in Table 1.

[0128] Table 1

[0129] Shape of the contact area Positive result Example 1 Figure 3 a 80% Example 2 Figure 3 b 100% Comparative Example 1 Figure 4 a 33% Comparative Example 2 Figure 4 b 40% Comparative Example 3 Figure 4 c 40%

[0130] It is clear that significantly improved results can be achieved by the shape of the contact area according to the invention. More than 50% of the samples were rejected in the comparative example, while a large number of positive results were observed in the embodiments according to the invention. It is particularly advantageous if the cutting line S extends beyond the endpoint of the gradually tapering end (Example 2).

[0131] List of reference numerals in the attached diagram:

[0132] (1) Multilayer films with electrocontrollable optical properties

[0133] (2) Active layer sequence of multilayer film 1

[0134] (2a) Ion storage layer of electrochromic layer sequence 2'

[0135] (2b) Electrolyte layer of electrochromic layer sequence 2'

[0136] (2c) Electrochromic layer of electrochromic layer sequence 2'

[0137] (3) First planar electrode of multilayer film 1

[0138] (4) Second planar electrode of multilayer film 1

[0139] (5) The first carrier membrane of the multilayer membrane 1

[0140] (6) The second carrier membrane of the multilayer membrane 1

[0141] (7.1) Busbar of the first planar electrode 4

[0142] (7.2) Busbar of the second planar electrode 4

[0143] (12) First glass plate

[0144] (13) Second glass plate

[0145] (14a) First thermoplastic bonding film

[0146] (14b) Second thermoplastic bonding film

[0147] (14c) Third thermoplastic bonding film

[0148] (15) Covering printed materials

[0149] (B) Contact area of ​​the second planar electrode 4

[0150] (B') Contact area of ​​the first planar electrode 3

[0151] (S) Cutting line

[0152] (S') incision

[0153] (α) The angle between the boundary line of contact area B and the segment adjacent to the endpoint of the gradually tapering end.

[0154] XX' section line.

Claims

1. Multilayer film (1) with electrically controllable optical properties, comprising the following components in the indicated order stacked on top of each other in a planar fashion: a) a first carrier film (5), b) a first planar electrode (3), c) an active layer or layer sequence (2) with electrically controllable optical properties, d) a second planar electrode (4) and e) a second carrier film (6), wherein in at least one contact area (B) the first carrier film (5), the first planar electrode (3) and the active layer or layer sequence (2) are removed so that the second planar electrode (4) is exposed, wherein the contact area (B) is designed in the form of a strip with a gradually tapering end.

2. Multilayer film (1) according to claim 1, wherein the contact area (B) is designed in the shape of an elongated hexagon.

3. Multilayer film (1) according to claim 1, wherein the contact area (B) is designed in the shape of a trapezoid.

4. Multilayer film (1) according to any one of claims 1 to 3, wherein the gradually tapering end is delimited by two touching segments of the boundary line of the contact area (B), which segments enclose an angle (a) of less than 90°.

5. Multilayer film (1) according to claim 4, wherein the gradually tapering end is delimited by two touching segments of the boundary line of the contact area (B), which segments enclose an angle (a) of 50° to 90°.

6. Multilayer film (1) according to any one of claims 1 to 3, wherein the gradually tapering end is delimited by two touching segments of the boundary line of the contact area (B), wherein in the prolongation of each of the segments a slit (S') is introduced into the first carrier film (5) with a length of at least 1 mm.

7. Multilayer film (1) according to any one of claims 1 to 3, wherein in the contact area (B) a busbar (7.2) is arranged on the second planar electrode (4), which busbar is designed in the form of a strip of an electrically conductive film.

8. Multilayer film (1) according to any one of claims 1 to 3, wherein in at least one further contact area (B') the second carrier film (6), the second planar electrode (4) and the active layer or layer sequence (2) are removed so that the first planar electrode (3) is exposed, wherein the further area (B') is also designed in the form of a strip with a gradually tapering end.

9. Multilayer film (1) according to any one of claims 1 to 3, which is an electrochromic multilayer film with an electrochromic active layer sequence, which comprises the following components in the indicated order stacked on top of each other in a planar fashion: - an ion storage layer (2a), - an electrolyte layer (2b) and - an electrochromic layer (2c).

10. Composite glass pane with a multilayer film (1) according to any one of claims 1 to 9, wherein the multilayer film (1) is arranged between two glassy glass panes (12, 13) and is joined to each glassy glass pane (12, 13) by at least one thermoplastic joining film (14a, 14b).

11. Method for the production of a multilayer film (1) with electrically controllable optical properties, wherein (A) providing a multilayer film (1) having electrically controllable optical properties, comprising at least the following components stacked on top of each other in the order indicated: a) a first carrier film (5), b) a first planar electrode (3), c) an active layer or layer sequence (2) having electrically controllable optical properties, d) a second planar electrode (4) and e) a second carrier film (6), (B) separating at least one region of the first carrier film (5) from the surrounding region of the first carrier film (5) by means of a cut (S'), wherein the cut (S') surrounds a contact region (B) in the form of a strip having tapered ends, (C) peeling off the region of the first carrier film (5) together with the region of the first planar electrode (3) adhering thereto starting from one of the tapered ends, (D) removing the optionally remaining active layer or layer sequence (2) from the second planar electrode (4) in the contact region (B).

12. The method according to claim 11, wherein the cut (S') in method step (B) is produced by radiation of a laser.

13. The method according to claim 12, wherein the wavelength of the radiation is from 3 pm to 50 pm.

14. The method according to claim 13, wherein the wavelength of the radiation is from 5 pm to 20 pm.

15. The method according to claim 12 or 13, wherein the power of the radiation is from 1 W to 50 W.

16. The method according to claim 15, wherein the power of the radiation is from 5 W to 20 W.

17. The method according to any one of claims 12 to 13, wherein the laser is operated pulsed with a pulse frequency of from 500 Hz to 5000 Hz and with a pulse length in the range of microseconds.

18. The method according to claim 17, wherein the laser is operated pulsed with a pulse frequency of from 1000 Hz to 3000 Hz and with a pulse length in the range of microseconds.

19. The method according to any one of claims 11 to 13, wherein the remaining active layer or layer sequence (2) is removed in method step (D) with an organic solvent.

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