WO2025088166A1 - Functional film and method for contacting a functional layer - Google Patents

Abstract

The invention relates to switchable functional film (32) for a vehicle window (11), comprising: - a first carrier film (22) having a first preferably segmented, electrically conductive coating (28), - a second carrier film (24) having a second electrically conductive coating (30), and - a preferably segmented functional layer (26) disposed between the two electrically conductive coatings (28, 30), characterized in that the first electrically conductive coating (28) is exposed at least in an area (31) and forms at least one insulating region (34) at least in the exposed area (31), wherein: furthermore a first segment (1) of the first electrically conductive coating (28) is electrically insulated from a second segment (2) of the first electrically conductive coating (28); at least one first electrically conductive conducting track (36) extends from the first segment (1), in the insulating region (34), to a contacting region (38); at least one second electrically conductive conducting track (42) extends from the second segment (2), in the insulating region (34), to the contacting region (38); in the contacting region (38), an electrical connector (29) electrically contacts the first and second conducting tracks (36, 42) by means of a crimp connection, for the purpose of electrically contacting the functional film (32).

Description

Functional film and method for contacting a functional layer

The invention relates to a functional film for a vehicle window according to the preamble of claim 1. Furthermore, the invention relates to a method for, in particular, electrically contacting a functional film which is used in a vehicle window.

A vehicle window with a switchable functional film is known from the prior art and represents, for example, a roof element that is adjustable or fixed relative to a vehicle body. The vehicle window is usually a composite component comprising an outer pane body and an inner pane body.

To switch a functional film, both sides of the switchable functional film must usually be electrically contacted. Contacting can be achieved using a variety of conceptual solutions. One example solution for electrically contacting the functional film is to solder individual conductor tracks. For example, delicate copper wires are used to contact the functional films and are soldered to a bus bar that has been previously applied to the conductive coating of the functional film. The copper wires are embedded or laid on the surrounding hot-melt adhesive film and led to a collective contact area on the bus bar, where they are again soldered to a connector that is led out of the glass for connection to a control unit. The bus bar can be soldered or glued on and is made of a conductive material (e.g. tin or copper). What all solutions have in common is that both sides of the functional film must be contacted separately. It is an object of the invention to provide an improved functional film and/or an improved method for contacting a functional film for a vehicle window.

This object is achieved according to the invention by a functional film having the features of patent claim 1. Furthermore, the object is achieved by a method for contacting a functional film having the features of patent claim 15.

Advantageous embodiments of the invention are the subject of the dependent claims. The scope of the invention includes all combinations of at least two features disclosed in the description, the claims, and/or the figures. It is particularly understood that customary linguistic transformations and/or analogous replacements of respective terms within the scope of common linguistic practice, in particular the use of synonyms supported by generally accepted linguistic literature, are encompassed by the present disclosure content without being explicitly mentioned in their respective formulation.

According to a first aspect, a switchable functional film for a vehicle window is proposed. The functional film is therefore preferably used in a vehicle window, in particular in an arrangement for variable optical transmission. The functional film can be understood here as a functional film arrangement, in particular having a multilayer structure. The functional film is designed in particular as a PDLC (polymer-dispersed liquid crystal), SPD (suspended particle device), EC (electrochrome), or LC (liquid crystal) arrangement. The functional film has a first carrier film with a first, preferably segmented, electrically conductive coating. The functional film comprises a second carrier film with a second electrically conductive coating and a preferably segmented functional layer arranged between the two electrically conductive coatings. The functional layer can be a PDLC (polymer-dispersed liquid crystal), SPD (suspended particle device), EC (electrochrome), or LC (liquid crystal) layer. The first electrically conductive coating is exposed in at least one surface area and is at least in the exposed Surface area is removed to form at least one insulating area in order to form at least a first segment and a second segment of the first electrically conductive coating. The first electrically conductive coating is exposed at least in one surface area and forms at least one insulating area at least in the exposed surface area, wherein furthermore a first segment of the first electrically conductive coating is electrically insulated from a second segment of the first electrically conductive coating. The first segment is preferably electrically insulated from the second segment by an insulating line. At least one first electrically conductive conductor track extends from the first segment in the insulating area or within the insulating area to a contacting area which is designed for electrical contacting of the functional film. The contacting area is preferably formed in the exposed surface area, preferably in an edge area and/or a corner area of the functional film. At least one second electrically conductive conductor track extends from the second segment in the insulating area or within the insulating area to the contacting area. An electrical connector, which preferably forms part of the functional film, electrically contacts the first and second conductor tracks in the contacting area for electrically contacting the functional film, each by means of a crimp connection.

In principle, there can also be additional insulating lines separating the conductor tracks. The conductor tracks can preferably extend from a segment of the electrically conductive coating through an insulating region, which can be separated from other segments by additional insulating lines. The conductor tracks therefore do not necessarily have to run through a region in which the coating has been removed, but can also be applied at least in sections to the electrically conductive coating. The insulated region of the electrically conductive coating can preferably be formed by additional insulating regions in the exposed surface. The conductor tracks can run through the insulated region(s).

In an alternative or supplementary aspect, which can in particular also be independently tracked, a switchable functional film for a vehicle window is proposed. The functional film is therefore preferably used in a vehicle window, in particular in an arrangement for variable optical transmission. The functional film is designed in particular as a PDLC (polymer-dispersed liquid crystal), SPD (suspended particle device), EC (electrochrome), or LC (liquid crystal) arrangement. The functional film has a first carrier film with a first, preferably segmented, electrically conductive coating. The functional film comprises a second carrier film with a second electrically conductive coating and a preferably segmented functional layer arranged between the two electrically conductive coatings. The functional layer can be a PDLC (polymer dispersed liquid crystal), SPD (suspended particle device), EC (electromagnetic encoder) or LC (liquid crystal) layer. The second electrically conductive coating is exposed in at least one (further) surface area. At least one electrically conductive connecting conductor track extends from the at least one (further) surface area to a contacting area which is designed for electrically contacting the functional film. The contacting area is preferably formed in the exposed surface area, preferably in an edge area and/or a corner area of the functional film. An electrical connector, which preferably forms part of the functional film, electrically contacts the connecting conductor track in the contacting area for electrically contacting the functional film, at least in sections, by means of a crimp connection.

According to a further aspect, a method for contacting a switchable functional film for a vehicle window is also proposed. The functional film is used in a vehicle window in a shading arrangement, in particular an arrangement for variable optical transmission. The method comprises the following steps: In a first step, a functional film is provided which has a first carrier film with a first, preferably segmented, electrically conductive coating, a second carrier film with a second electrically conductive coating, and a preferably segmented functional layer arranged between the two electrically conductive coatings, wherein the first electrically conductive coating is exposed at least in one surface area and forms at least one insulating region in the exposed surface area, wherein furthermore a first segment of the first electrically conductive coating is a second segment of the first electrically conductive coating is electrically insulated, wherein at least one first electrically conductive conductor track extends from the first segment in the insulating region to a contacting region, wherein at least one second electrically conductive conductor track extends from the second segment in the insulating region to the contacting region. In a further step, an electrical connector is provided. In a further step, crimping or creating a crimp connection of the electrical connector with the first and second conductor tracks and/or the connecting conductor track, which is applied to the second electrically conductive coating, at least in the contacting region for electrically contacting the functional film.

It is understood that the method according to the second aspect may comprise several intermediate steps and/or sub-steps, and that the listed steps do not necessarily have to be carried out in the described order.

The present switchable functional film can be contacted easily and cost-effectively and does not require a large number of sequential process steps. The present functional film can therefore be manufactured with low production effort and a shorter cycle time. Furthermore, the functional film can be made flexible, so that even production-related bending of the functional film does not negatively impact its functionality. Furthermore, the present crimping enables large-area contacting, which has greater mechanical resilience than point-to-point contacting. The printed and/or otherwise applied conductor tracks offer high adhesion to the carrier substrate, in particular the conductive coating and/or the carrier film, preferably compared to a soldered/glued conductor track, and result in high mechanical flexibility of the functional layer. Contacting by means of a mechanical connection (preferably a crimp connection) also represents a mechanically stable connection that is resistant to chemical and/or thermal stress (compared to adhesive connections). Soldering and gluing processes are also avoided, which reduces the risk of failure of the functional foil due to contact loss. The mechanical connection (preferably crimp connection) takes care of both the electrical contact and the absorption of mechanical loads. The entire contacting of the functional foil can be carried out for all segments of the positive electrode (first or second electrically conductive coating) as well as the negative electrode (second or first electrically conductive coating) in the contacting area, in particular at a single location. The crimps can generally also be used in a design in which the power rails/busbars do not extend to a common connection area. This enables the use of a small or short electrical connector and thus offers cost-saving potential. The contacting effort is reduced because the functional foil can be contacted at just one position and in a single contacting process. By using a crimp connection, insulated electrical connectors can also be used without having to first strip them in one area in order to make electrical contact.

The invention therefore relates to a more robust contacting solution for segmented and unsegmented functional foils using printed and/or applied conductor tracks, which are contacted both electrically and mechanically in the contacting area. The segment-wise energization and/or control of the functional foil is preferably achieved by applying conductive conductor tracks to the previously exposed conductive coating of the respective carrier foil. The conductor tracks are preferably insulated from one another by structuring the conductive coating in order to thus form the at least one insulating area. This enables the segment-wise control and/or energization of the functional foil. In a single, collective contacting area, the conductor tracks are preferably contacted with the electrical connector, which can also be described as a common conductor. The functional foil can be connected to a voltage source and/or a control unit via the electrical connector. The contacting of the preferably printed conductor tracks and the electrical connector is preferably achieved by means of a mechanical contacting process. The mechanical contacting process can particularly preferably be a crimping process. A crimp connection created in this way preferably creates a mechanical clamping by penetrating the busbar, the underlying conductor track and the carrier foil together with the electrically conductive coating and/or pressing the individual layers together. By penetrating the individual layers and/or plies, an electrically conductive connection is created in addition to the mechanical pressing or fixing. This enables a current flow between the applied conductor track and the electrical connector. The current flow is preferably enabled by the crimping mechanism that connects the conductor track and the electrical connector. The mechanical, current-carrying, or electrically conductive, connection between the respective conductor tracks and the electrical connector is thus provided by the crimp connection.

The electrical connector can preferably be attached to the conductor tracks of the functional film in an overlapping manner or as a butt connection in the contacting area, wherein the electrical connector is preferably attached on or to a (common) side of the functional film. In other words, the electrical connector can preferably be attached from one side of the film. Contacting of the second electrically conductive coating is preferably carried out in the same way by means of a crimp connection. The crimp connection is preferably produced on the side of the carrier film having the second electrically conductive coating. The crimp is preferably applied from the same side of the film that is connected to both coatings. In order to contact the electrical connector by means of the crimp connection, the electrical conductors in the electrical connector do not have to be insulated (or stripped) beforehand. The electrically conductive connection is in fact preferably produced by crimping through and thus contacting the enclosed conductor track of the electrical connector. The connector may be insulated as indicated here, but there may also be embodiments in which the connector is partially without insulation or the insulation is applied only to one side of the connector.

In its intended use, the functional film is used in an arrangement for variable optical transmission, which in turn is used in a vehicle window to provide a shading function and/or a roller blind function. Even though the present invention is described for an arrangement for variable optical transmission, this is not to be understood as limiting. so that all statements and/or descriptions - unless technically excluded - should also be read as referring to a PDLC arrangement.

The conductor tracks preferably extend at least partially in or within the insulating region from one segment into the contacting region, without touching and/or electrically contacting another segment. The conductor tracks can also be insulated from one another by additional insulating lines. The individual segments of the first segmented, electrically conductive coating are each electrically contacted by the conductor tracks and guided to the contacting region.

It goes without saying that additional segments can also be present. It also goes without saying that the first electrically conductive coating does not have to be completely removed, but that only a portion of the first electrically conductive coating can be removed. The first and/or second segment can, for example, also comprise a path of the conductor track applied later, but are electrically insulated from one another. In this case, the conductor track is applied to the first electrically conductive coating. The path along which the respective conductor track is to be applied does not necessarily have to be removed from the first electrically conductive coating, but can remain, with the insulating region then being formed, for example, by at least partially and/or sectionally slitting and/or scoring the first electrically conductive coating. The first electrically conductive conductor track is particularly preferably applied to the insulating region and/or at least partially to the first electrically conductive coating. It is also understood that the first and/or second coatings do not necessarily have to be (pre-)segmented; rather, segmentation of the first and/or second coatings can also occur prior to provision. The second coating does not necessarily have to be segmented. It is merely advantageous for one of the two coatings to be segmented so that the roller blind function and/or the segment-by-segment switching of the film can be implemented.

The invention therefore relates to a contacting solution for the electrical connection and/or contacting of a preferably pre-segmented functional film, in order to be able to supply them with current segmentally during their intended use. Whether the functional film is segmented depends on its type, for example, whether it is based on PDLC, LC, or SPD, is optional or required. In this way, a functional film contacted according to the method can be used to form an arrangement for variable optical transmission, which can be switched and/or supplied with current segmentally during the application. This can, for example, provide a roller blind function.

The exposure of the first segmented, electrically conductive coating at least in one surface region can preferably be provided in any desired manner. For example, the surface region can be created by cutting the second carrier film together with an underlying functional layer (also generally referred to as a kiss cut). Any residues of the functional layer on the first, segmented, electrically conductive coating can then be removed by cleaning. In the exposed surface region, the second carrier film is preferably ablated and/or removed together with the second electrically conductive coating and the liquid crystal arrangement.

In this case, the first segmented, electrically conductive coating is stripped at least in certain areas or partially to form the insulating region, ultimately enabling the segmental current supply to the individual segments. The first and second carrier films preferably comprise PET. The first segmented, electrically conductive coating and/or the second segmented, electrically conductive coating preferably comprise indium tin oxide (ITO). Other, preferably transparent, electrically conductive coatings may also be used.

The invention therefore relates to a space-optimized and/or space-saving contacting solution for electrically contacting the individual functional layer segments, in particular by means of printed, preferably digitally printed conductor tracks and using a crimping process.

In one embodiment, the crimp connection of the, in particular electrically insulated, electrical connector, the at least first and/or second conductor track and/or the first electrically conductive coating and/or the first carrier film, wherein the crimp connection further mechanically connects the electrical connector to the functional layer. A crimp connection is preferably a method for establishing an electrical, mechanical, and/or structural connection between two or more components by using special crimping tools or devices to create a connection. This is preferably achieved by compressing and/or deforming a metal part, referred to as a "crimp plug" or "crimp contact," to create a firm connection to another object, such as a cable, wire, or circuit board. The electrical connector is preferably electrically insulated, with the conductor tracks of the connector preferably being enclosed with an electrically insulating material. It is also possible for the electrical connector to have partially exposed conductor track areas, or for only one side of the conductor track to be electrically insulated and the second side to be exposed for contacting. In addition to the mechanical connection, the electrical connection between the electrical connector and at least one conductor track or the underlying electrically conductive coating is also implemented.

The crimp connections can have a width of 0.5 mm to 2 mm and/or a length of 5 mm to 15 mm. For example, the crimp connections are a maximum of 1 mm thick. This allows them to be easily integrated into a composite disc structure.

In one embodiment, the at least one insulating region is formed by at least partially removing and/or incising the first electrically conductive coating at least in the exposed surface area. The removal and/or incision can be carried out by means of a cutting tool, for example a blade and/or by means of laser abrasion and/or by means of a laser cutting process. Other removal methods are also conceivable in principle. The insulating region of the first segmented, electrically conductive coating is preferably formed by stripping by a laser and/or etching by an etchant and/or by mechanical removal, in particular by means of a brush and/or a blade and/or a scraping tool. The respective coating can also be removed in other ways, including by other abrasive methods. Removal by laser or etching is advantageous due to the structural accuracy that can be achieved. For example, a _CO2 laser can also be used for removal. The laser is preferably operated in continuous wave mode, but can in principle also be operated in pulsed mode. The laser power is preferably 0.1 W to 200 W, particularly preferably 1 W to 25 W. For decoating, the laser beam is preferably focused on the first segmented, electrically conductive coating, which ensures a high power density and a thin cutting line. Mechanical removal, e.g. using a rotating brush, is cost-effective. In principle, mechanical removal can also be achieved by scoring with a knife. This is a particularly simple way of isolating individual segments and requires a simple structural manufacturing setup.

In one embodiment, the first carrier film and/or the second carrier film comprise/comprising a plastic, preferably PET. In principle, other plastics and/or plastic mixtures are also conceivable and, depending on the application, may be advantageous over PET. For example, PEN (polyethylene naphthalate), ABS (acrylonitrile butadiene styrene), PC (polycarbonate), PL (polyester), and/or PI (polyimide) are also suitable. Particularly preferably, the first electrically conductive coating and/or the second electrically conductive coating comprise/comprising an ITO layer.

In one embodiment, the first and/or second electrically conductive conductor track (and/or also further conductor tracks) is/are printed and/or applied in some other way and/or vapor-deposited using an electrically conductive ink and/or an electrically conductive paint and/or an electrically conductive paste. The application of electrically conductive conductor tracks therefore preferably comprises printing the at least one insulating region and/or also partially the first electrically conductive coating with an electrically conductive paint and/or ink and/or applying an electrically conductive paste and/or ink. Such an ink and/or paint and/or paste particularly preferably comprises high flexibility and is particularly suitable for printing on, for example, PET or, for example, coated PET substrates using ITO or on other preferably flexible substrates. As a result, the printed and/or applied conductor tracks are not damaged or impaired during further production and/or further manufacturing steps of the functional layer, even in the event of bending and/or curving. It may be preferred that at least one stencil and/or a printing mask is used during printing and/or application and/or a digital printing process is employed. This makes it possible to achieve a structured and predefined shape for the conductor tracks. In addition, the conductor tracks can also have complex track paths. In one embodiment, the second conductor track preferably follows the first conductor track at least in one track section, so that the conductor tracks preferably comprise a course that is congruent or similar to one another (± 10%), at least in sections. The conductor tracks are thus guided to the, in particular, common contact region, which is preferably arranged at an end region of the exposed surface area. The contact region preferably also serves as an electrical contact for the second electrically conductive coating. In particular, the second electrically conductive coating is to be contacted next to the first electrically conductive coating, since the second coating and the carrier film are removed in the connection area of the first electrically conductive coating.

In one embodiment, the second electrically conductive coating is exposed in a further surface area, wherein at least one connecting conductor track in the further surface area is at least partially printed and/or applied to the second electrically conductive coating and runs at least partially to the contacting area or adjacent to the contacting area, wherein the electrical connector in the contacting area for electrically contacting the functional film electrically contacts the connecting conductor track through a further crimp connection. The connecting conductor track can also run alongside the contacting area by the connector extending into the area of the connecting conductor track. The structural and/or material statements made for the provision of the conductor tracks apply equally to the connecting conductor track. The connecting conductor track establishes, in particular, a common contact with the other electrode or the second electrically conductive coating of the functional layer. The second electrically conductive coating is therefore preferably not to be contacted segment by segment, but can be The electrical conductor is guided into the contacting area and electrically contacted there by the electrical connector. The at least one connecting conductor applied to the second electrically conductive coating preferably runs in the direction of the contacting area. The electrical connector, which is located on the side of the first electrically conductive coating, contacts the at least one connecting conductor via a crimp connection. Thus, both electrically conductive coatings that are in contact with the conductors are contacted by a connector lying on only one side of the functional film via the crimp connection. This simplifies the contacting process.

For example, the distance between the centers of adjacent crimp connections is a maximum of 2.54 mm, in particular 1.27 mm to 2.54 mm. In particular, the distance between the centers of adjacent crimp connections depends on the selected crimp connections.

In one embodiment, the electrical connector overlaps at least partially with the first and/or second electrically conductive trace on the first conductive coating. The surface area for the connecting trace is applied to the second electrically conductive coating and is thus located opposite or on the other side of the first electrically conductive coating. Contacting can be made from the same side, since the crimp contact "pierces" through the carrier substrate and the ITO coating (second electrically conductive coating) and thus reaches or contacts the trace (applied to the second electrically conductive coating).

In one embodiment, the electrical connector is in contact with the first carrier film and the first conductive coating at least in sections.

In one embodiment, an edge seal is provided in an edge region of the exposed surface area. The at least one connecting conductor track extends, for example, over the preferably stepped edge region into the contacting area in order to guide the electrode formed by the second coating to a common connection point. The connecting conductor track is preferably printed over the edge seal, so that the edge seal is provided. before the connecting conductor track is applied. If the connecting conductor track is printed on, a print head is preferably able to print the connecting conductor track in the stepped edge region in order to guide it into the contacting region as uninterruptedly as possible. In one embodiment, at least one of the at least one connecting conductor track can extend beyond the edge region. In principle, contacting of the connecting conductor track can also take place in a particularly flat region of the second carrier film, so that the at least one connecting conductor track does not necessarily have to extend over the edge region. The edge region is preferably to be understood as a kiss-cut edge. This is purely optional. Due to the flexibility of the electrical connector, it can also be guided over the edge region. An edge seal and/or edge gasket can also be provided in the exposed surface area.

In one embodiment, at least the first and/or the second electrically conductive conductor track widens in the at least one contacting region to form at least one contact point. Preferably, all or at least one of the conductor tracks can widen in the contact point to enable improved contacting or to provide a larger contact surface. The conductor tracks extend into the common contacting region and are connected there by means of crimps to the electrical connector and preferably to the electrically conductive coating. The individual conductor tracks preferably do not come into electrical contact with one another, since otherwise individual control of the segments would not be possible.

For example, the conductor tracks are connected to the electrical connector via the crimp connections in their extension plane, i.e. without them experiencing any curvature or kinking.

The crimp connections each have, for example, a flat connection surface, which, in particular, lies flat against a respective electrically conductive conductor track. The connection surface can be designed in such a way that it ensures a flat and/or consistent connection between the crimp connection and the respective electrically conductive conductor track. This prevents voltage spikes. cracks in the contact surfaces and damage to the electrically conductive tracks.

For example, the crimp connections are in surface contact with one of the electrically conductive tracks. This surface contact ensures low contact resistance, so that heating due to contact resistance is minimal or nonexistent.

The crimp connections can include pointed and/or sharp-edged teeth, which particularly penetrate the electrically conductive traces. This largely eliminates any risk of damage to the electrically conductive traces.

The teeth are designed, for example, in such a way that they connect the electrically conductive conductor tracks to the connector, in particular in a form-fitting and/or force-fitting manner, and enable, for example, a current and/or signal flow between the connector and the electrically conductive conductor tracks.

The crimp connections may have a coating. The coating may include tin and/or gold, or be made of one of the aforementioned materials. This improves the corrosion resistance of the crimp connections.

In one embodiment, the electrical connector comprises a flexible printed circuit board (FPCB), and/or a Kapton, and/or an FFC, and/or a jumper cable, wherein the electrical connector is configured to electrically connect the functional film to a voltage source. A flexible printed circuit board (FPCB) is preferably a thin, flexible circuit board that can establish electrical connections. Kapton is a heat-resistant, flexible material used as a substrate for electronic components. A flexible flat cable (FFC) is a flat, flexible cable with multiple conductive tracks that is used to transmit signals or power. A jumper cable is a short, preferably flexible cable that is used to establish connections between components.

In one embodiment, the electrically conductive tracks and/or insulating layers are flexible after printing. This has the advantage that, compared to State of the art technology ensures that even if the functional foil is bent, no conductor track will become detached and thus the contact will not be damaged.

In one embodiment, the electrically conductive traces are pre-dried after application, particularly by intense pulsed light (IPL). Pre-drying can also be performed by a laser or thermally using hot air and/or infrared and/or an oven and/or UV radiation. Pre-drying can be useful if complete drying is to take place in an autoclave. However, it is also possible that the aforementioned methods can be used for direct, complete drying. The optional pre-drying of the ink and/or paint and/or paste is carried out to achieve improved handling strength. IPL has the advantage of a short cycle time, as only a short energy input time is necessary. Compared to thermal drying, only a few seconds, for example 10-30 seconds, are required, whereas with thermal drying, a cycle time of approximately 2-30 minutes can be expected. Pre-drying and possibly post-drying, particularly in an autoclave, can have a positive effect on the production time and/or the cycle time. Alternatively, post-drying or post-curing and/or complete drying are possible. Complete drying in a single step is possible with all of the above-mentioned processes. Pre-drying offers the advantage of reducing cycle times, as the post-drying (sintering) can be performed in an autoclave. A subsequent autoclave process is then preferably used to produce the glass composite. This process can then be used directly for complete drying or sintering.

In one embodiment, at least the following steps are performed to provide the processed functional layer: heating the functional layer on the side of the first carrier film; and detaching a defined region of the second carrier film, together with a portion of the functional layer adhering in this region, from the first carrier film, such that the first conductive coating of the first carrier film is exposed in a surface area corresponding to the detached region of the second carrier film, preferably without residues of the functional layer. The first conductive coating is preferably freed from the functional layer without leaving any residue. It has been shown that by heating the functional film on one or both sides, the other side of the functional layer can be separated as a unit with the functional material (PDLC (polymer-dispersed liquid crystal), SPD (suspended particle device), EC (electrochrome), or LC (liquid crystal)) due to the reduced adhesion forces between the functional material and the conductive coating of the first carrier film. The cohesive forces of the functional material, in particular as a layer and/or film, and the adhesion forces between the functional material and the electrically conductive coating of the second carrier film are preferably retained. This makes it possible to remove the functional material from the electrically conductive coating of the first carrier film without damaging the electrically conductive coating. The removal process can be carried out quickly and with a high level of occupational safety, as no solvents are required. Furthermore, high reproducibility is guaranteed. The defined area of the second carrier film is reproducible, so that a rapid industrial implementation of the method according to the invention is also possible.

The functional film is, for example, a cut-out of a film composite formed from the first carrier film with the first electrically conductive coating, the second carrier film with the second electrically conductive coating, and the functional layer arranged therebetween. Cutting the functional layer can be integrated into the method according to the invention.

After carrying out the preferred method, the resulting functional film processed in this way can be further processed. According to the invention, the exposed conductive coating of the first carrier film can be contacted, allowing connection to a control system, and the arrangement for variable optical transmission can be integrated into the composite structure of a vehicle window, for example, by being arranged between two window bodies. The composite structure of the vehicle window can comprise further plastic films and/or layers arranged on one or more window bodies and/or can comprise an ambient light functionality. For example, at least one hot-melt adhesive film is arranged between an outer window body and/or between an inner window body and the first or second carrier film. and/or a functional coating, such as for reflection or absorption of light of a specific wavelength.

The arrangement for variable optical transmission of the manufactured vehicle window forms, in particular, a shading arrangement that can be switched between a blocking state and a transmission state by applying appropriate electrical voltages via the connected electrical control. The vehicle window thus formed is particularly suitable as a pane of a vehicle roof, which can be part of a fixed roof element rigidly arranged relative to a vehicle body or of a cover element that can be displaced relative to the vehicle body by means of appropriate drive kinematics.

According to the invention, at least one of the two electrically conductive coatings of the two carrier films of the functional layer is segmented, whereby separate contacting of the segments of the respective electrically conductive coating is possible by applying the method according to the invention.

In a specific embodiment of the method according to the invention, the functional layer on the side of the first carrier film is heated such that the first carrier film assumes a temperature of 60°C to 220°C, in particular a temperature of 60°C to 150°C and preferably a temperature of 60°C to 100°C. These temperature ranges are particularly suitable when using a PET film as the carrier film, the melting temperature of which is approximately 260°C.

The preferred method does not require any mechanical processing of the exposed electrically conductive coating, so that it is solvent-free and also free of cleaning traces.

In a specific embodiment, the defined region of the second carrier film, together with the portion of the functional layer adhering to this region, is removed using a separating tool. The separating tool is preferably applied to the structure of the functional layer without contact with the electrically conductive coating of the first carrier film. In order to clearly define the area in which the second carrier film, together with the portion of the functional layer adhering in this area, is detached from the first carrier film, in a preferred embodiment of the method, the defined area is created by severing the second carrier film along a cutting line without mechanically processing the first carrier film and its electrically conductive coating, i.e., without being affected by the cutting process. Such a cutting process is also frequently referred to as a kiss cut or half cut.

The defined region in which the electrically conductive coating of the first carrier film is exposed by the method according to the invention can have a strip shape, an L-shape, a U-shape, or a frame shape. It is also conceivable for the defined region to be formed by a local surface section, which can have any desired geometry. Each of these geometric shapes can be minimized to the width of the conductor tracks according to the invention.

In order to assist the detachment of the second carrier film and the portion of the functional layer adhering thereto from the first carrier film, in a special embodiment the functional layer is held outside the defined area during detachment thereof by means of a hold-down device.

The present method may further comprise: crimping the electrical connector in the region of the at least one connecting conductor track applied to the second electrically conductive coating in order to energize the second electrically conductive coating.

For example, the electrical connector is crimped to a large number of conductor tracks at the same time.

To further support the detachment process and to ensure the adhesion forces between the functional layer and the electrically conductive coating of the second carrier film, in a special embodiment of the functional layer, cooling is carried out on the side of the second carrier film during the detachment of the defined area of the second carrier film. Particularly preferred is a shading arrangement, in particular an arrangement for variable optical transmission, which comprises a functional layer according to the invention. The shading arrangement is preferably provided to provide a shading function for a vehicle.

Also preferred is a vehicle window with a functional film. The vehicle window in question is fundamentally arbitrary. It can preferably be a windshield, a rear window, a side window, a partition, and/or an openable and/or non-openable vehicle roof window, for example, a sunroof or a panoramic roof. The vehicle can be a commercial vehicle, a passenger vehicle, a truck, and/or a transport vehicle.

Further advantages and advantageous embodiments of the subject matter of the invention can be found in the description, the drawings and the patent claims.

An embodiment of a method according to the invention is explained in more detail below with reference to the drawing. It shows:

Figure 1 is a schematic view of a roof area of a motor vehicle;

Figure 2 shows a section through a pane of the vehicle roof;

Figure 3 is a schematic view of an embodiment of a functional film; and

Figure 4 is a schematic view of an embodiment of a functional film.

Figure 1 shows a motor vehicle 10 comprising a vehicle roof 12 provided with a fixed roof element 14 that is rigidly or immovably connected to a vehicle body. The fixed roof element 14 forms a vehicle window 11, which is designed with a shading function so that the incidence of light into an interior of the motor vehicle 10 via the fixed roof element 14 can be controlled. The vehicle roof 12 extends along a vehicle longitudinal direction. x and a vehicle width direction y. The vehicle longitudinal direction x is orthogonal to the vehicle width direction y.

The fixed roof element 14 or the vehicle window 11 has a composite structure, which can be seen schematically in Figure 2, and which comprises an outer window body 16, which forms an outer visible surface of the fixed roof element 14 facing the vehicle's surroundings, and an inner window body 18, which forms an inner visible surface of the fixed roof element 14 accessible from the vehicle interior. Between the outer window body 16 and the inner window body 18, a shading arrangement 20 or an arrangement for variable optical transmission is arranged, which represents a shading system for the vehicle window 11. The shading arrangement 20 comprises, for example, a PLDC arrangement (polymer-dispersed liquid crystal arrangement). The shading arrangement 20 is connected to the outer pane body 16 and the inner pane body 18 via adhesive layers not shown in detail, which comprise PVB (polyvinyl butyral) and/or EVA (ethylene vinyl acetate) and/or TPU (thermoplastic polyurethane).

The shading arrangement 20 comprises a first carrier film 22 and a second carrier film 24. A functional layer 26, in particular a PDLC layer or a PDLC mass, is arranged between the two carrier films 22 and 24, which in this exemplary embodiment forms the functionally effective element of the shading arrangement 20. The functional layer 26 can be segmented. The segmentation of the functional layer 26 is only optional when using PDLC and can accordingly also be unsegmented in another exemplary embodiment. The carrier films 22 and 24, which can each be formed from a material such as PET or the like, each have an electrically conductive, in particular transparent, coating 28 or 30 on their side facing the functional layer 26, which forms an electrode layer and is formed in the present case from an ITO coating (indium tin oxide coating).

The first electrically conductive coating 28 is segmented in this case. The second electrical coating 30 can also be segmented. It is also conceivable that both electrical coatings 28, 30 are segmented. Other electrically conductive coatings are also conceivable. The segmentation of the first electrically conductive capable coating 28 is indicated in Figure 2 by vertical lines. The segmentation can be carried out, for example, by removing the first electrically conductive coating 28 and/or by severing the functional layer 26, for example by a laser. The segmentation can be carried out, for example, by ablating and/or cutting through the first electrically conductive coating 28, e.g. with a laser. For this purpose, a _CO2 laser, as described in more detail above, or mechanical severing can be used. A total of three segments 1, 2, 3 can be seen in Figure 2, whereby the designation by the respective reference symbols is made once for reasons of clarity.

In Figure 3, however, four segments 1, 2, 3, 4 can be seen. The segmentation of the first electrically conductive coating 28 corresponds to the segments of the functional layer 26, with each segment 1, 2, 3, 4 of the first electrically conductive coating 28 being assigned to a segment of the functional layer 26. Since the segmentation of the functional layer 26 is optional to the segmentation of the first electrically conductive coating 28, reference is made below only to segments 1 to n. The number of segments is not limited. The segments may comprise other shapes, which may be the same or different.

By applying a first potential to the segmented, first electrically conductive coating 28 and a second potential, which differs from the first potential, to the second electrically conductive coating 30, a voltage can be applied to the functional layer 26, which is also a functional layer, by means of a control device (not shown in detail), so that the optical transmission behavior of the functional layer 26 can be changed in the regions corresponding to the segments where the electrical voltage is applied. Preferably, the first potential and/or the second potential are alternating potentials. Thus, each individual segment 1, 2, 3, 4 of the functional layer 26 or of the shading arrangement 20 can be switched between a blocking state, in which the respective segment 1, 2, 3, 4 of the functional layer 26 strongly scatters light due to the non-directional liquid crystals, and a transmission state, in which the respective segment 1, 2, 3, 4 of the functional layer 26 is optically transmissive and thus portions of the light can enter the vehicle interior predominantly unscattered through the vehicle window. The functional layer 26 preferably forms the shading arrangement 20 and preferably comprises a polymer matrix in which liquid crystals are incorporated in droplet form.

In order to enable the individual segments 1, 2, 3, 4 to be energized and/or controlled, they must be electrically contacted or, accordingly, a voltage field must be applied. The first carrier film 22 of the shading arrangement 20 has, for example, a greater length in the vehicle longitudinal direction x of the fixed roof element 14 than the second carrier film 24, so that a surface area 31 of the first carrier film 22, designed as a contact strip (see an exemplary section of such a surface area 31 in Figure 3), is exposed in the lateral edge areas. Via this respective exposed surface area 31, the first segmented, electrically conductive coating 28 can be contacted segment by segment or connected to the control device and/or power supply (not shown in detail) via a flexible electrical connector 29, for example an FPCB (flexible printed circuit board) and/or a Kapton and/or an FFC and/or a jumper cable.

During the production of the shading arrangement 20 or in preparation thereof for contacting and lamination into the composite structure shown in Figure 2, the functional film 32 is preferably first provided. This preferably has the dimensions that the first carrier film 22 has in the installed position of the arrangement for variable optical transmission 20. Subsequently, a so-called kiss-cut process is preferably carried out on the functional layer 32, in which the second carrier film 24 is severed along a cutting line S without the separation process resulting in mechanical stress on the first carrier film 22 and the coating 28.

The functional film 32 is then heated, preferably on the side of the first carrier film 22, such that the first carrier film 22 assumes a temperature of approximately 80°C to 100°C. By means of a corresponding separating tool (not shown), the area defined by the cutting line S, together with the section of the functional layer 26 adhering to the second carrier film 24 in this area, can be separated, in particular without residue, from the first carrier film 22 and its second, electrically conductive coating. Layering 28 is removed, so that the exposed surface area 31 of the coating 28 of the first carrier film 22 results in the edge area.

Figures 3 and 4 provide a more detailed look at the contacting of the functional film 32 processed in this way with the at least one exposed surface area 31. In Figure 3, the second carrier film 24 is transparent, so that the underlying functional layer 26 can also be seen in the non-exposed area of the functional film 32. Even if segmentation has already taken place, the segmented, electrically conductive coating 28 can optionally be removed at least in some areas and/or sections, at least in the exposed surface area 31, to form at least one insulating area 34, by means of which the individual segments 1, 2, 3, 4 of the first segmented, electrically conductive coating 28 are also electrically insulated from one another in the vehicle width direction y. The at least regional and/or section-wise removal of the first segmented, electrically conductive coating 28 preferably comprises cutting into the first segmented, electrically conductive coating 28 or stripping it with a laser and/or etching it with an etchant. In the present case, the at least one insulating region 34 is formed by cutting lines of different lengths along the vehicle width direction y.

According to the invention, at least one first electrically conductive conductor track 36 extends from the first segment 1 in or within the insulating region 34 insulated from segment 2 to a contacting region 38, which is designed for electrically contacting the shading arrangement 20. The first conductor track 36 is, for example, printed or otherwise applied in the insulating region 34 onto the first carrier film 22 or onto the first electrically conductive coating 28.

In order to electrically contact the second segment 2 and lead it into the contacting region 38, a second electrically conductive conductor track 40 is applied, in particular printed, to the first carrier film 22 or to the first electrically conductive coating 28 in the insulating region 34 extending in the vehicle width direction y between the first and second segments and between the second and third segments. In order to electrically contact the third segment 3 and lead it into the contacting area 38, a third electrically conductive conductor track 42 is applied, in particular printed, to the first carrier film 22 or to the first electrically conductive coating 28 in the insulating area 34 extending in the vehicle width direction y between the second and third segments and between the third and fourth segments.

In order to electrically contact the fourth segment 4 and lead it into the contacting region 38, a fourth electrically conductive conductor track 44 is applied, in particular printed, to the first carrier film 22 or to the first electrically conductive coating 28 in the insulating region 34 extending in the vehicle width direction y between the third and fourth segments.

According to the invention, the electrical connector 29 in the contacting area 38 for electrically contacting the functional film 32 electrically contacts the first to fourth conductor tracks 36, 40, 42, 44 via a crimp connection. For this purpose, the electrical connector 29 has at least four conductor tracks 46. Each of the conductor tracks 46 electrically contacts one of the conductor tracks 36, 40, 42, 44 via the crimp connection. The crimp connection is identified by reference numeral 48.

The second electrically conductive coating 30 is exposed in a further surface area 50. This surface area 50 can be exposed using a kiss-cut process. Laser ablation and/or a laser cutting process are also conceivable. The statements regarding surface area 31 apply accordingly here.

At least one connecting conductor track 52 is printed and/or applied in the further surface area 50, at least partially, on the second electrically conductive coating 30 and/or on the second carrier film 24. The connecting conductor track should be located entirely in the exposed area 50. However, it can also be routed beyond the kiss-cut edge into the common contacting area (in particular on the opposite side). If the connecting conductor track extends beyond the kiss-cut edge of the cut, it particularly touches the first carrier film. The connecting conductor track 52 runs at least in sections to the contacting area 38, wherein the electrical connector 29 in the contacting area 38 for electrically contacting the functional film 32 connects the connecting conductor track 52. by means of a further crimp connection 54. The connecting conductor track 52 is electrically contacted by a further conductor track 46 of the electrical connector 29 by crimping. Optionally, an edge seal is provided in an edge region of the exposed surface area 31. Such an edge seal is also possible in the surface area 50 at the kiss-cut edge.

The contacting region 38 may comprise a portion adjacent to the surface region 31. The connecting conductor track 52 need not extend out of the kiss-cut region and may be adjacent to the other kiss-cut region 31. Furthermore, the connector 29 need not have any conductor tracks that change direction, as shown in Figures 3 and 4. The connector 29 may be wide enough so that the conductor tracks 46 can reach each of the conductor tracks 36, 40, 42, 44, including the connecting conductor track 52 on the other side of the functional film 26. The connections may all be made from the same side, thus avoiding more complicated connection designs. A slot may be introduced into the connector 29 in the region of the kiss-cut S so that a change in thickness does not affect the connector 29 and its conductor tracks 46. The common connecting conductor track 52 does not have to be connected to a conductor track pointing in the same direction, so that the deflections shown are merely exemplary.

According to Fig. 3, an overlap connection is shown. This means that the electrical connector 29 at least partially overlaps with the functional foil 32, or the conductor tracks 36, 40, 42, 44 overlap with the conductor tracks 46 in the contacting area 38. The same applies to the connecting conductor track 52.

According to Fig. 4, however, a butt connection is shown. Otherwise, the statements made with regard to Fig. 3 also apply to Fig. 4. A butt connection for electrical connection by crimping preferably refers to a special method of crimping in which two or more conductor tracks are connected by simply placing their ends together. This method enables a quick and temporary electrical connection without the need for special plugs or connectors. The advantage is that the connector 29 and the conductor tracks are not arranged one above the other, but lie against one another in a butt joint. This re- Reduces the material thickness of the substrate in the area of the connector 29 or the contacting area. In a butt joint, the bare ends of the conductor tracks are crimped together using a crimping technique, thereby connecting them mechanically and electrically. Crimping pliers or another tool are often used to apply pressure to the crimped areas and create a secure connection.

List of reference symbols

1 segment

2 segments

3 segments

4 segments

10 motor vehicle

11 Vehicle window

12 Vehicle roof

14 fixed roof element

16 disc outer body

18 disc inner body

20 Shading arrangement

22 first carrier film

24 second carrier film

26 Functional layer

28 first coating

29 electrical connector

30 second coating

31 Area

32 functional foil

32' processed functional film

34 Isolation area

36 first conductor track

38 Contact area

40 second conductor track

42 third conductor track

44 fourth conductor track

46 conductor tracks

48 Crimp connection

50 area

52 connecting conductor track 54 Crimp connection x Vehicle longitudinal direction y Vehicle width direction

S cutting line

Claims

Patent claims 1. Switchable functional film (32) for a vehicle window (11), comprising: - a first carrier film (22) with a first segmented, electrically conductive coating (28), - a second carrier film (24) with a second electrically conductive coating (30), and - a segmented functional layer (26) arranged between the two electrically conductive coatings (28, 30), characterized in that the first electrically conductive coating (28) is exposed at least in one surface region (31) and forms at least one insulating region (34) at least in the exposed surface region (31), wherein a first segment (1) of the first electrically conductive coating (28) is electrically insulated from a second segment (2) of the first electrically conductive coating (28), wherein at least one first electrically conductive conductor track (36) extends from the first segment (1) in the insulating region (34) to a contacting region (38), wherein at least one second electrically conductive conductor track (42) extends from the second segment (2) in the insulating region (34) to the contacting region (38); wherein an electrical connector (29) in the contacting region (38) for electrically contacting the functional film (32) electrically contacts the first and second conductor tracks (36, 42) by means of a crimp connection. 2. Functional film (32) according to claim 1, wherein the crimp connection of the, in particular electrically insulated, electrical connector (29), the at least first and/or second conductor track (36, 42) and/or the first electrically conductive layer Layering (28) and/or the first carrier film (22) is penetrable, wherein the electrical connector (29) is further mechanically and/or electrically connectable to the functional layer (32) by means of the crimp connection. 3. Functional film (32) according to claim 1 or 2, wherein the at least one insulating region (34) is formed by at least partially removing and/or cutting the first electrically conductive coating at least in the exposed surface region (31). 4. Functional film (32) according to one of the preceding claims, characterized in that the first carrier film (22) and/or the second carrier film (24) comprises a plastic, preferably PET. 5. Functional film (32) according to one of the preceding claims, characterized in that the first electrically conductive coating (28) and/or the second electrically conductive coating (30) comprises an ITO layer. 6. Functional film (32) according to one of the preceding claims, characterized in that the first and/or the second electrically conductive conductor track (36, 42) is/are printed and/or applied by means of an electrically conductive ink and/or an electrically conductive paste and/or an electrically conductive paint. 7. Functional film (32) according to one of the preceding claims, characterized in that the second electrically conductive coating (30) is exposed in a further surface area (50), wherein at least one connecting conductor track (52) in the further surface area (50) is at least partially printed and/or applied to the second electrically conductive coating (30) and runs at least in sections to the contacting area (38) or adjacent to the contacting area (38), wherein the electrical connector (29) in the contacting area (38) for electrically contacting the functional film (32) electrically contacts the connecting conductor track (52) by means of a further crimp connection. 8. Functional film (32) according to one of the preceding claims, characterized in that the electrical connector (29) overlaps at least partially with the first and/or with the second electrically conductive conductor track (36, 42) on the first conductive coating (28). 9. Functional film (32) according to one of the preceding claims, characterized in that the electrical connector (29) rests against the first carrier film (22) and the first conductive coating (28) at least in sections. 10. Functional film (32) according to one of the preceding claims, characterized in that an edge seal is provided in an edge region of the exposed surface region (31). 11. Functional film (32) according to one of the preceding claims, characterized in that at least the first and/or the second electrically conductive conductor track (36, 42) widens in the at least one contacting region (38) to form a contact point. 12. Functional film (32) according to one of the preceding claims, characterized in that the electrical connector (29) comprises a flexible printed circuit board, FPCB, and/or a Kapton and/or an FFC and/or a jumper cable, wherein the electrical connector (29) is designed to electrically connect the functional film (32) to a voltage source. 13. Vehicle window (11) with a functional film (32) according to one of claims 1 to 12. 14. A method for contacting a functional film (32) for a shading arrangement (20) of a vehicle window (11), the method comprising the steps: - Providing a functional film (32) comprising a first carrier film (22) with a first segmented, electrically conductive coating (28), a second carrier film (24) with a second electrically conductive coating (30), and a segmented functional layer (26) which is arranged between the two electrically conductive coatings. Layers (28, 30) are arranged, wherein the first electrically conductive coating (28) is exposed at least in one surface area (31) and forms at least one insulating area (34) in the exposed surface area (31), wherein furthermore a first segment (1) of the first electrically conductive coating 5 layering (28) is electrically insulated from a second segment (2) of the first electrically conductive coating (28), wherein at least one first electrically conductive conductor track (36) extends from the first segment (1) in the insulating region (34) to a contacting region (38), wherein at least one second electrically conductive conductor track (42) extends from the second segment (2) in the insulated region (34) to the contacting region (38); - providing an electrical connector (29); - Crimping the electrical connector (29) with the first and second conductor tracks (36, 42) at least in the contacting area (38) for electrically contacting the functional film (32). 15 15. The method of claim 14, further comprising: Crimping the electrical connector (29) in the region of the at least one connecting conductor track (52) applied to the second electrically conductive coating (30).