NL2035073B1

NL2035073B1 - Method for segmenting a functional sheet structure and segmented functional layer for automotive windows

Info

Publication number: NL2035073B1
Application number: NL2035073A
Authority: NL
Inventors: Leonardus Marinus Borcherd Driehuis Bartholomeus; Laurens Koolen Timo
Original assignee: Autoglas D & K B V
Priority date: 2023-06-12
Filing date: 2023-06-12
Publication date: 2024-12-19
Also published as: WO2024258282A1

Abstract

The present invention is related to a method for segmenting a functional sheet structure for automotive, comprising the steps of obtaining at least one sheet 5 structure, the at least one sheet structure comprising at least two thermoplastic layers, wherein mutually facing sides of the thermoplastic layers are provided with a conductive coating, and at least one, preferably switchable, film layer arranged between the at least two thermoplastic layers, wherein the sheet structure further comprises at least one connection surface, for electrically connecting the sheet 10 structure to a power source forming at least two, mutually electrically separated, segments in the at least one sheet structure, preferably by local removal of at least one thermoplastic layer with conductive coating, and optionally the film layer. The present invention is further related to a segmented functional layer for use in an automotive window laminate and an automotive window laminate comprising the 15 same.

Description

Method for segmenting a functional sheet structure and segmented functional layer for automotive windows

The present invention is related to a method for segmenting a functional sheet structure for automotive. The present invention is furthermore related to a segmented functional layer for use in an automotive window laminate. According to a further aspect the present invention is related to an automotive window laminate and a vehicle comprising the same.

Nowadays, thermoplastic laminated sheet structures comprising at least one functional layer like polymer-dispersed liquid-crystal (PDLC), Electro Chrome and other functional films like suspended-particle devices (SPD) are widely used in architectural glasses but are - more exceptionally — also used in the automotive industry. There are several reasons for that but in general, in the automotive industry, there is a higher demand in both safety regulations and quality issues. As an example, homologation in the automotive industry requires destructive tests, such as dropping steel balls from a height onto the window laminate structure, but also less destructive tests such as optical performance and boiling tests, to be passed.

By providing such a functional layer in an automotive window laminate structure additional functionalities may be obtained. A first, but not limitative, example of such a functionality is the ability to switch the layer between opaque and transparent, which may be achieved by applying current to the connector of the functional layer. In case of a liquid crystal dispersion, the current makes the crystals align such that the layer becomes transparent. This may for example be of use in a roof window of a vehicle, for example to prevent sun from entering the cabin.

However, other appliances of said functional layer are conceivable.

A downside of these functional layers is typically the lack of freedom. That is, the layer is mostly to be switched on or off, i.e., transparent or opaque in its entirety.

However, current roof or other window blinds may allow for half-way or arbitrary positions of the screen. This is however difficult to obtain in respect of the functional fayer, which to this end must be segmented, resulting in complex connections, and less than ideal manufacturing processes.

Therefore it is a goal of the present invention to provide for a segmented functional layer for use in automotive industries particularly, which is easier to produce. it is a second goal to provide a segmented functional layer which has a more robust connection.

It is a third goal of the present invention to provide for a functional layer which allows for increased design freedom.

The present invention thereto provides a method for segmenting a functional sheet structure for automotive, comprising the steps of:

A) obtaining at least one sheet structure, the at least one sheet structure comprising at least two thermoplastic layers, wherein mutually facing sides of the thermoplastic layers are provided with a conductive coating, and at least one, preferably switchable, film layer arranged at least partially between the at least two thermoplastic layers, preferably wherein the sheet structure further comprises at least one connection surface, for electrically connecting the sheet structure to a power source;

B) forming at least two, mutually electrically separated, segments in the at least one sheet structure, preferably by local removal of at least one thermoplastic layer and/or conductive coating, and optionally the film layer;

C) forming of at least two, mutually electrically separated, segment connectors on the connection surface, wherein the at least one, preferably at least two, in particular all, segment connectors are formed by local removal of at least a portion of the conductive coating on the connection surface.

The present invention according to the method allows for increased degree of freedom in the production of the segmented functional layer compared to the prior art. The present invention requires only a step of separating two segments to form the specific segments. Moreover, the connectors may be easily formed by a similar electrical separation step, which provides for great flexibility in terms of the shape of the segments and/or the connectors. Since both the connectors and the segments may be formed by a simple, electrical, separation step, a more robust segment and connector may be established. That is, the need for accurate alignment of connectors and segments may be substantially eliminated. Since the present invention may allow for merely removing material, such as to form an electrical separation. The aforementioned benefits additional allow for an increased simplicity in the manufacturing process which may result in a lower cost price. In addition, the present invention may be applied to standard functional layers available on the marked. It is a significant benefit to be able to use standard pre- fabricated. Hence, no need for custom fabrication of the functional layer, in particular sheet structure, from scratch which may further reduce costs and increase flexibility of the fabrication process. It is preferred that forming the electrically separated segments and/or connectors is achieved through local removal of material, in particular through local removal of conductive material.

Preferably, locally material is removed from at least one thermoplastic layer, the conductive coating on said thermoplastic layer, and optionally the film layer. Hence, the sheet structure and/or the connection surface as such remains intact, that is to be understood as remain a single tangible object. Hence, removing material is done such as to form two electrically isolated area’s on the initial sheet structure.

The at least one sheet structure may for example be a standard sheet structure, in particular a PDLC sheet structure. However, different available functional layers such as Suspended Particle Devices (SPD) and/or Electro Chrome (EC) on the market may also constitute the sheet structure according to the present invention.

Typically such a functional layer may be bought on rolls of a standard with and standard length. it is conceivable that the method comprises a sub step of cutting, preferably laser cutting, the obtained functional layer to a predetermined size. Such asize may correspond to a specific window laminate in which the functional layer is to be installed. It is a significant benefit to be able to use standard pre-fabricated.

As such, this may allow the present invention to use a bulk product, whilst still being able to provide for a customized segmentation. This may increase the overall efficiency of production as well as freedom in design.

In the present invention, electrically separated may be understood as not resulting in short circuit. Hence, two adjacent segments of the functional layer are not electrically connected, at least one the different poles to prevent short circuit. It is preferred that the two segments are separated by a portion that is free of conductive material, in particular by a portion of one thermoplastic layer from which the conductive coating is removed. However, it may be conceivable that electrical separation is established by means of a difference in conductivity, hence a low and a high conductivity. Preferably, the connectors comprise a high conductivity, whereas the separation between adjacent connectors comprises a low conductivity.

It has turned out this may provide for sufficient electrical separation between connectors such as to form electrically isolated connectors. Therefore, instead of electrically separated segments and/or connectors, it is also conceivable that areas of high conductivity (in particular the segments and/or connectors) and low conductivity (separation) are defined. Preferably, the areas of high conductivity, i.e., the connectors are configured for conducting an electric power between 0.5 Watt per square meter and 10 Watt per square meter, in particular between 2.0 Watt per square meter and 8.0 Watt per square meter, more in particular about 4.0 Watt per square meter. The latter has in particular been proven to provide good functionality for PDLC in motor vehicles since these are generally of a relatively large size.

Preferably, the connectors are configured for conducting an electric power suitable for use with PDLC and/or SPD films, Since these need a relatively high power for switching. This may provide for sufficient power to switch at least one segment from opaque to transparent. The conductive coating may in particular be an Indium Tin

Oxide (ITO) coating. However, it is conceivable that other transparent conducting oxides, such as Galium, or Zing, or the like may be used in a conductive coating.

Preferably, step B) and step C) according to the present invention are achieved by means of only local removal of material. That is, said connectors and/or segments may be formed by merely removing material, without requiring a step of adding material, in particular without adding material after the step of removing the material. This may provide that a standard functional layer may be used and can be segmented. In particular forming the connectors in this way may increase the accuracy, and eliminates need for accurate placement of connectors a posteriori.

Moreover, the present invention may achieve great accuracy improvements over screen printing techniques or other printing techniques for forming connectors in functional layers. It allows for a more accurate coupling of connector and segment.

The connection surface may be formed by a portion of one of the thermoplastic layers which extends beyond the film layer and the other thermoplastic layer. Said inwardly facing surface of the thermoplastic layer extending beyond the film layer and other thermoplastic layer may for the connection surface as such. Hence, it is preferred that the connection surface forms integral part of the sheet structure. In particular the portion of conductive coating that is to be removed may be merely a line between two adjacent connectors and/or segments, such as to separate the connectors and/or segments. Preferably, the steps according to the method, in 5 particular steps A), B), and C) are consecutive steps, optionally with intermediate steps.

According to a preferred embodiment, the method further comprises the step of:

D) providing a layer of conductive material onto at least a portion of the connection surface, said layer of conductive material being in contact with the conductive coating of at least one thermoplastic layer of the sheet structure. Preferably, step

D) is performed prior to step C), more preferably prior to steps B) and C). It is conceivable that the layer of conductive material is a layer of conductive ink. The layer of conductive material may be different than the conductive coating that is already present on the thermoplastic layer. It is preferred that the layer of conductive material is in contact, in particular in electrically conductive contact with the conductive coating of said thermoplastic layer. This may allow the layer of conductive material to be used as an connection to the functional layer, in particular to be able to switch the functional layer by applying a power to the layer of conductive material, in particular once connectors are formed. It is imaginable that step D) is performed by a supplier of the functional layer, such that the aforementioned “standard” functional layer comprises a portion wherein between opposing thermoplastic layers a layer of conductive material is provided. Said layer of conductive material locally substituting the film layer. In particular said portion wherein between opposing thermoplastic layers a layer of conductive material is provided forms, at least part of, the connection surface. It is conceivable that that the layer of conductive material covers, at least initially, hence prior to step B) and

C), the entire surface of the connection surface. The layer of conductive material preferably has a thickness situated between 0.1 um and 200 um preferably between 1.0 um and 100 um. The thickness of the layer of conductive material may depend on the percentage of conductive material in the layer, in particular the ink, the desired quality and the specific conductive materials which been used. For example if Silver at 60% parts per weight is used, a 10 #% layer would be suitable. it can be imaginable that if a thicker conductive layer is used, this may also function to compensate thickness of layers that are, if applied, removed. The silver layer may for example be a silver ink. Preferably, the layer of conductive material has a conductivity which is higher compared to the ITO (or the conductive coating in general). In particular said layer of conductive material is formed at least partially by

Silver. Preferably, said layer of conductive material is a silver layer. Other alternatives like brass, carbon, and/or gold are however also conceivable.

According to a preferred embodiment, during step C, the segment connectors are formed by local removal of at least a portion of the conductive material provided in step D) and preferably the conductive coating of the thermoplastic layer. In particular, step C) may be to locally electrically separate the layer of conductive material provided in step D) and optionally also the conductive coating of the thermoplastic layer, in particular the thermoplastic layer that forms the connection surface. By locally separating, which may be understood as locally electrically separating, the layer of conductive material two or more distinct conductive surfaces may be defined on the connection surface. Hence, by separating the layer of conductive material into at least two electrically separated conductive surfaces two connectors may be established. Preferably, only a single connector is connected to a specific segment, since otherwise short circuits may arise. The width of the connector may be substantially the same as the width of the segment.

Optionally, the method further comprises the step of removing a part of at least one thermoplastic layer and a part of the film layer, at least along a portion of at least one edge of the sheet structure. Preferably, said remaining thermoplastic layer may define the at least one connection surface of the sheet structure. It is preferred that this step is performed after step A), but prior to step B), C), and D). This step may allow for defining a connection surface on any standard functional layer, such as a standard PDLC layer. It is conceivable the method further comprises the step of applying a covering thermoplastic layer onto at least one, preferably each, connector and/or at least one track, if applied. In particular, said latter step is performed after step B) and/or step C) and/or step D). The covering thermoplastic layer may optionally be the part of the at least one thermoplastic layer that was initially removed. Yet, it is also conceivable that the covering thermoplastic layer applied onto the at least one connector and/or segment at least partially overlaps with a portion of thermoplastic material, i.e., of the functional layer, that was not removed, in particular adjacent to the connection surface. Preferably, said covering thermoplastic layer that is applied is a self and/or heat and/or pressure activated covering thermoplastic layer, in particular a self and/or heat and/or pressure activated adhesive covering thermoplastic layer. The heat and/or pressure activated covering thermoplastic layer may also be referred to as heat and/or pressure activated covering film.

According to a preferred embodiment at least one segment and/or at least one segment connector is formed during step B) and/or step C) by means of laser cutting. Laser cutting in particular may allow for forming at least one connector and at least one segment in a single cutting step. In particular it may allow for forming of at least one segment and the particular connector connected to said at least one segment in a single step. The laser has proven to be effective and accurate. It is conceivable that a laser intensity is adjusted when the laser cut transitions from the segment to the segment connector. The laser intensity may also be referred to as a laser power. The intensity is typically affected by a laser speed, in particular a speed of travel in the direction of the cutting plane, and the laser frequency. It is preferred these parameters are monitored and adjusted according to the layers to be cut. In particular, the laser power and/or intensity are adjusted during a consecutive laser cut, in particular during a transition from a segment, or segment to be formed, to the connection surface and/or the connector to be formed, in particular the electrically separated segment connector. This is preferred since the layers that are present may be different and hence cutting with a constant laser intensity may yield unwanted layers to be separated. It is conceivable to adjust the taser intensity by for example an appropriate adjustment in speed or laser frequency. That is, the laser may move at a certain speed over a segment to be formed, such as to separate, that is electrically, two mutual segments. Said certain speed for example corresponding to a laser intensity that allows for cutting the first thermoplastic layer and conductive coating, and optionally the film layer, but not the second thermoplastic layer. The conductive coating of the second thermoplastic layer is preferably removed by said laser cut. Once the laser is about to move to the connection surface, the laser speed may be decreased, or increased, depending on the thickness of the connection surface. If, said connection surface is formed by one thermoplastic layer, which is provided with said layer of conductive material such as silver, it is typically required to increase the intensity by decreasing the speed of the laser. However, if no such layer of conductive material (silver) is provided onto the already present conducive coating, said movement speed may be increased in fact to prevent the laser from cutting through the connection surface in its entirety. As an alternative to laser cutting, it is conceivable that an accurate knife or blade may achieve similar results.

Typically all laser settings have an influence on the speed and quality of the cut.

The laserspot diameter is preferably be between 0.5 4m and 200 pon, in particular between 1 4m and 100 um, more preferably between 9 um and 35 um. In addition to the laserspot diameter the frequency, power and pulse duration have an influence. Good results may be obtained at a power of 20 Watt, a frequency of 20 kHz, a pulse duration of 200 ns and a speed of 300 mm/min. These settings also vary on the desired quality. Preferably, the laser is a CNC-coded laser. The accuracy of the laser-cut is preferably situated between 0.05 mm and 0.15 mm, in particular 0.1 mm, in particular reproducible within 0.01 mm. The power of the laser on the connection surface is typically between two and four times, in particular three times, as large as the power of the laser on the segment area. The latter obviously depending on the exact material and thickness that is applied.

Preferably, at least one segment and/or at least one respective segment connector are formed by means of a continuous step, preferably a single processing step, in particular by means of a continuous laser cut, preferably a single continuous laser cut. Said laser cut is preferably consecutive, such that by a single laser cutting step it is possible to obtain both a segment and a connector, in particular wherein said segment and connector smoothly transition into one another, such that substantially no misalignment is present where the connector is connected to the segment. lt may be readily understood that temporarily pausing the laser and subsequently continuing from said paused position may fall within the wording of a single processing step, in particular if said pause does not involve further technical alterations to the functional layer. The laser may move along a predefined track, and in doing so form electrical separation on the sheet structure corresponding to a specific segment and respective connector. lt is in particular advantageous that the single cut allows to form both the segment its respective connector as this may fully eliminate the need to align specific connectors to specific segments which may greatly improve the robustness of manufacturing and the product.

According to an embodiment, the method further comprises the step of: E) providing or forming at least two electrically conductive track onto the connection surface, wherein each electrically conductive track is electrically connected to at least one segment connector. Preferably, each electrically conductive track is electrically isolated from the other track(s) in order to prevent short circuits. It is conceivable that the tracks are formed by the conductive coating of the thermoplastic layer and optionally the layer of conductive material provided onto the conductive coating. Preferably at least one electrically conductive track is integrally formed with a respective connector. In particular, formed by the same material layers. Hence, there is no material transition between the track and the connector to which the track is connected. This is greatly advantageous for the connectivity and the robustness. One or more tracks, in particular each track is preferably formed by means of, preferably the same, a continuous laser cut as mentioned before. Hence, it is conceivable that the at least one segment, the respective segment connector and the respective electrically conductive track are formed through a single cut, preferably a single laser cut, which in particular may be continuous. The separated electrically conductive tracks may be formed by local removal of conductive material in the same manner as the different connectors and segments may be formed.

Preferably, the at least two electrically conductive tracks and the at least two segment connectors are arranged adjacent to a single edge of the sheet structure.

Preferably, said conductive tracks and segment connectors are each provided onto the connection surface, wherein in particular the connection surface is arranged along a single edge of the sheet structure. That is, one thermoplastic layer forming the connection surface may extend beyond the remaining layers of the sheet structure along a single edge. This may provide for a simple architecture wherein the connectors and the tracks are efficiently oriented along a single edge, which may provide benefits for installation.

According to a preferred embodiment, during step C) the at least two segment connectors, and optionally the at least two tracks provided during step E), are formed by simultaneously removing the conductive coating on the thermoplastic layer and a layer of conductive material provided onto said conductive coating.

Hence, for example a laser may be arranged to have its intensity adjusted to remove the layer of conductive material, such as silver, and the conductive coating on the thermoplastic layer, in particular the thermoplastic layer forming the connection surface. This may establish electrical isolation of the separate tracks, connectors, and segments.

The present invention is further related to a segmented functional layer for use in an automotive window laminate structure, wherein the functional layer comprises: at least one sheet structure, comprising at least two thermoplastic layers, wherein mutually facing sides, preferably mutually facing sides of the thermoplastic layers, are provided with a conductive coating, at least one, preferably switchable, film layer arranged between the at least two thermoplastic layers, preferably wherein said sheet structure, in particular the at least one film, is divided in at least two segments, at least one connection surface, preferably formed by a part of one of the at least two thermoplastic layers, comprising at least two electrically separated segment connectors, each for connecting a segment to a power source, wherein at least one, preferably each, segment connector is formed by an area of conductive material provided onto the conductive coating of the thermoplastic layer forming the connection surface. The benefits as elucidated with respect to the method are also applicable to the segmented functional layer according to this aspect of the present invention. The present invention is furthermore related to a segmented functional layer obtained by the method according to the present invention.

It is imaginable that the conductive coating on the connection surface is co-planar with the conductive coating of at least one thermoplastic layer of the sheet structure. The area of conductive material provided onto the conductive coating is therefore situated, partially, at a raised level with respect to the conductive coating of at least one thermoplastic layer of the sheet structure. The connector is thereby formed by a stack of two layers, wherein in particular said area of conductive material allows for sufficient conductivity. It is imaginable that the electric conductivity of the conductive coating is different with respect to the electric conductivity of the area of conductive material, in particular wherein the electric conductivity of the area of conductive material is higher. The electrically separated connectors may be formed by adjacent areas of conductive material provided onto conductive coating, wherein at least the adjacent areas of said conductive coating are not in, electrical, contact. That is, between such connectors it is, depending on the conductivity of the conductive coating, not required to remove all conductive coating between said adjacent connectors, although this may reduce the risk of short circuit.

Optionally, at least one covering thermoplastic layer is provided onto at least one connector. Preferably, said covering thermoplastic layer that is applied is a heat and/or pressure activated covering thermoplastic layer, in particular a heat and/or pressure activated adhesive covering thermoplastic layer. The heat and/or pressure activated covering thermoplastic layer may also be referred to as heat and/or pressure activated film. Preferably, said covering thermoplastic layer at least partially overlaps with a portion of the functional layer, in particular a thermoplastic layer of the functional layer, adjacent to the connection surface. It is imaginable that said covering thermoplastic layer covers substantially all connectors and/or tracks on the connection surface. This may allow a difference in thickness caused by the, possibly cascaded, connection surface to be compensated. Additionally, this may prevent the formed connectors and/or tracks from being damaged and/or pressed together, in particular during forming of an automotive window due to pressure.

Electric current may cause Electro Magnetic Interference (EMI) and/or electromagnetic susceptibility (EMS), the higher the voltage or current, the stronger the magnetic fields are. In particular EMI or EMS may cause problems on the connection surface of the functional layer, for example the voltage applied on the one or more tracks. These magnetic fields in the form of EMI and/or EMS may interfere with other electronic devices, such as communication systems, car electronics or even neighbouring tracks from the functional layer itself. This is an even bigger problem with alternating current, especially if square waves are used. it is known that these square waves may reduce haze levels for PDLC and SPD devices, but it also tend to increase EMI. Therefore, it is preferred that the EMI is absorbed and/or reduced. It is conceivable that functional layers, such as PDLC and/or SPD devices are used in a laminated window structure, in particular a glass sheet which is coated with a conductive coating such as Ag or Low-e coating. Said coating may act as a shield to EMI, however if a higher protection level is wanted, or if no coating is present on the glass sheet it may we desirable to have at least one electromagnetic interference (EMI) and/or electromagnetic susceptibility (EMS) shielding layer close to the electric connections and or tracks, so that EMI may at least partially be shielded off. To this end, preferably at least one electromagnetic interference (EMI) and/or electromagnetic susceptibility (EMS) shielding layer is provided onto at least a portion of the connection surface. Preferably said EMI and/or EMS shielding layer covers at least a portion of the conductive material that is electrically separated from at least one connector and/or at least one electrically conductive track. Optionally, the layer of conductive material that is electrically separate from said connectors and/or tracks may as such form the shielding layer.

It is conceivable that the EMI and/or EMS shielding layer is provided onto a surface of the at least one covering thermoplastic layer, in particular the surface facing towards the connection surface, preferably wherein the EMI and/or EMS shielding layer is electrically isolated from the one or more connectors and/or tracks. The

EMI and/or EMS shielding layer may at least partially be composed out of conductive material or a conductive mesh. The shielding layer may allow for reducing the magnitude of electromagnetic interference. It is imaginable that the electrically separated silver layer or ink, in particular on the connection surface, may be provided with an additional conductive layer or the cover layer is provided with a compatible electric conductive layer for EMI shielding purposes, in particular if no neighbouring layers have electric conductive properties. The level of shielding provided by the shielding layer is related to the resistivity and the distance of the shielding layer(s). For example, a 0,8 chm / square meter 3ag shielding layer may shield most of the electromagnetic waves from a 48 volts sinus wave PDLC device. it is therefore imaginable that the covering thermoplastic layer is provided with said shielding layer, in particular the inwardly facing surface thereof. Preferably, the covering layer is at least partially coated and/or printed such that any direct electric contact, between the one or more track(s) on the connection surface and the shielding layer is avoided. The shielding layer may be on both sides of the film and may also be formed from separated ‘ground’ tracks between connectors and/or tracks, which are preferably formed by means of a laser. tis conceivable that the following prefabricate may be suitable for creating a segmented functional layer according to the present invention, which is hereto also covered; segmentable functional layer for use in an automotive window laminate structure, wherein the functional layer comprises: at least one sheet structure, comprising, at least two thermoplastic layers, wherein mutually facing sides are provided with a conductive coating, at least one, preferably switchable, film layer arranged between the at least two thermoplastic layers, at least one connection surface, preferably formed by a part of one of the at least two thermoplastic layers, comprising; at least one layer of conductive material, covering at least a portion of conductive coating of said connection surface, preferably covering substantially the entire connection surface. In particular wherein said connection surface is arranged for forming therein two or more electrically separated segment connectors, each for connecting a respective segment to a power source.

Preferably, said area of conductive material and the conductive coating of the thermoplastic layer, in particular which area of conductive material and the conductive coating defining a segment connector, have mutually substantially coinciding boundaries. Hence, as seen from a top, or bottom, view the perimeter of the area of conductive material coincides with the perimeter of the conductive coating that together form a segment connector. The top, or bottom view in this respect may be understood as the view towards the plane in which the segmented functional layer is oriented.

It is imaginable that at least one, preferably each, segment connector is electrically connected to at least one electrically conductive track, wherein said electrically conductive track is provided onto the at least one connection surface. The track allows to electrically connect the segment from a central or predetermined point to the power source. It may for example be unpractical to connect all segment connectors individually to the power source, since they may be at a distance which would require some complex wiring. Via tracks, which may be relatively thin, a central connection for one or more segment connectors may be arranged at a different location. For example, each track may rung to a specific area, for example on a side or corner of the connection surface, which allows for local connection of each of the tracks to the power source, and hence as such connecting the segment connectors to the power source, via the tracks.

According to a preferred embodiment the at least one track, preferably each track, is formed by an area of conductive material provided onto the conductive coating of the thermoplastic layer forming the connection surface. Preferably, the at least one electrically conductive track and the segment connector are substantially integral.

This may be understood as the conductive coating and the area of conductive material forming such a segment connector to, preferably uninterruptedly, continue into the track. Thus, the transition between the track and the connector is substantially undetectable, and may be formed by a narrow track that widens into the connector. Hence, it may be conceivable that both the at least one segment connector and the at least one track are formed by the same and/or consecutive: and/or continuous and/or uniform area of conductive material. It is imaginable that along at least a portion of at least one, preferably each, track the area of conductive material and the conductive coating that form said track have mutually substantially coinciding boundaries. At least seen from the top or bottom view.

According to a preferred embodiment, at least a portion of the at least one connection surface is formed by a part of at least one thermoplastic layer which extends beyond the perimeter of the other thermoplastic layer and/or film layer. In particular substantially the entire connection surface is formed by a part of at least one of the thermoplastic layers, and the conductive coating on said thermoplastic layer, of the sheet structure which extends beyond the perimeter of the other thermoplastic layer and/or film layer. Preferably, the connection surface stretches at least along one edge of the sheet structure, however it may be imaginable that according to specific connection requirements, and the number of segments formed, it may stretch along at least two edges, for example two adjacent edges, or two opposing edges.

Preferably a width of a part of at least one segment connector substantially corresponds to a width of the respective segment of the sheet structure. Hence, the width of a segment connector, in particular the side facing the, in particular connected to, the segment is the same or substantially the same as said segment.

This may be achieved by the continuous laser cut forming the segment and the segment connector. This allows a decent electrical connection between the segment connector and the segment to be established.

It is imaginable that the width of at least one segment connector decreases in width, at least seen in the direction from the side of the segment connector connected to the respective segment towards a side of the segment connector that is, or may be, connected to a track. Preferably, said decrease in width of the connector is a substantially smooth decrease in width, such as a curved shaped width reduction at least as seen from a top or bottom view.

Preferably, at least one segment, and at least one segment connector, and at least one connector track, are formed by a single cut, in particular a single continuous laser cut, said laser cut electrically separating said segment, segment connector, and connector track from any other segments, segment connectors and connector tracks. In particular, this allows for forming a segment, a respective segment connector and optionally at least one connector track in a single step. As a consequence, there is no need for aligning the connector to the segment, nor requiring alignment of a track with respect to a connector. This significantly improves the accuracy that may be achieved in the final segmented functional layer. Thus, increasing the design freedom through increased accuracy.

The present invention is furthermore related to an automotive window laminate structure, comprising a first glass sheet, and a second glass sheet, said first and second glass sheet are parallel and mutually spaced apart, at least one thermoplastic laminated sheet structure, said thermoplastic laminated sheet structure substantially entirely placed between the first and second glass sheet, said laminated sheet structure comprising, at least one segmented functional layer, in particular a segmented functional layer according to the present invention, having an upper and lower surface, at least two bonding layers, wherein the at least two bonding layers substantially entirely cover the upper and lower surfaces of the at least one functional layer, wherein a portion of the bonding layers extends beyond a portion of the perimeter of the functional layer. The same advantages apply with respect to the automotive window laminate structure as elucidated based on the method and the segmented functional layer.

Preferably at least one segment connector of the segmented functional layer is at least partially sealed by at least one bonding layer of the thermoplastic laminated sheet structure. This may for example be achieved by the bonding layer covering the connection surface. That is, at least one bonding layer substantially covers the inwardly facing surface of the thermoplastic layer forming the connection surface, once heated, the bonding layer may become at least partially viscous and as such seal at least a portion of the connection surface. Preferably, said bonding layer seals at least one or more segment connectors and one or more tracks. It is also conceivable that an intermediate seal, such as an electrically isolating layer, is provided onto the inwardly facing surface of said thermoplastic layer, hence the connection surface, to electrically isolate the one or more tracks and segment connectors prior to sealing said connection surface with at least one bonding layer.

The invention is furthermore related to a transport vehicle, such as a car, bus, or a truck, provided with an automotive window laminate structure according to any of the preceding claims.

The present invention will be further elucidated with reference to the non-limitative embodiments shown in the following figures, wherein: - Figure 1a-1f shows an embodiment according to the method of the present invention; - Figure 2 shows an example of a functional layer according to an aspect of the present invention; - Figure 3 shows a different example of a functional layer according to an aspect of the present invention; - Figure 4 shows a segmented functional layer according to an embodiment of the present invention; - Figures 5i-5iii show three different cross-sections of the segmented functional layer of figure 4, and - Figure 6 shows an automotive window laminate according to the present invention.

Figures 1a-1í show different steps of the method for making a segmented functional layer 100 according to a non-limitative embodiment. Here figure 1a shows a first step of obtaining a sheet structure 101, which in this non-limitative embodiment is a standard functional layer 101, possibly store-bought. The functional layer 101 may be composed of at least two thermoplastic layers wherein mutually facing sides of the thermoplastic layers are provided with a conductive coating. Between said thermoplastic layers a film layer, in particular a switchable film layer is arranged. The sheet structure 101 may be a PDLC sheet structure. The standard sheet structure 101 may be cut to a format 102 corresponding to a specific function. The format 102 indicated in this figure may for example correspond to a functional layer 101 that is to be placed in a roof window of a vehicle. This particular shape functional layer 102 may be cut out of the sheet structure 101 by means of a laser cut. The thus obtained functional layer 102 is shown in figure 1b, wherein figure 1b furthermore indicates the step of forming a connection surface 104 in the functional layer 102. This connection surface is obtained by means of removing by a laser cut 103, at least removing the top thermoplastic layer and the film layer. The cross section A-A’ indicated in figure 1b may be similar in composition as the functional layer indicated in figure 2. Although this figure indicates a dedicated step for forming the connection surface, it is also conceivable that the functional layer 101 obtained in step a) already comprises such a connection surface 104. In figure 1c a layer of conductive material 105 is provided on the connection surface 104. The layer of conductive material 105 is preferably directly provided on the conductive coating of the thermoplastic layer that forms the connection surface 104. This may be elaborated in more detail based on the cross section B-B’, which has a similar composition compared to the functional layer shown in figure 3. The layer of conductive material 105 may for example be a silver layer provided onto preferably the entire connection surface 104. Applying such a layer of conductive material 105 may increase the electrical conductivity of the connection surface 104, which may provide better connection properties. In figure 1d a first boundary of a first segment is formed by means of laser cut 106. Said laser cut 106 may optionally be a regular cut, or removal of material, as long as it locally separates, at least electrically, portions of the functional layer 102 which may be elucidated in more detail based on figure 5. The laser cut 106 preferably cuts through at least one thermoplastic layer and preferably also the film layer, more preferably also the conductive coating of the other thermoplastic layer. Hence, the adjacent uncut portions are locally separated by a non-conductive portion, wherein non-conductive may be understood as having a sufficiently low electrical conductivity to prevent short circuit between two adjacent segments. The cut 106 shown in figure 1d stretches from the first boundary of the functional layer 102 to the transition from the functional layer 102 to the connection surface 104. Figure 1e shows a detailed view of encircled portion

C indicated in figure 1d. Figure 1e shows how a segment connector 111 is formed by means of a laser cut 107, 108. The laser cut 106 forming the segments transitions to the connection surface at transition point 114, it is preferred that a laser intensity is adjusted at or around transition point 14 which may allow to compensate the laser intensity for the different later compositions in the functional layer 102 and the connection surface 104. For example, it may require a higher laser intensity to cut through the layer of conductive material 105, which may be silver, compared to the thermoplastic layer and film layer of the functional layer 102. Hence, the laser may reduce speed to increase intensity moving from cut 106 to cut 107. The laser cut 107 moves over the connection surface, and in doing so locally separates a part of the connector 111 from adjacent parts.

To this end the laser cut 107 locally removes the layer of conductive material 105 and preferably also the conductive coating, however, the laser cut 107 does not remove, hence cut through, the thermoplastic layer forming the connection surface.

This figure shows that the transition from forming the segment boundary to forming the connector, hence laser cuts 106 and 107, are continuous.

This is advantageous since it allows for a near perfect alignment of the connector 111 to the segment to be formed.

In this non-limitative embodiment the continuous single cut 107 transitions into a track 112. The cut returns 108 to form the other portion of the track 112 and the other portion of the connector 111, and subsequently to form the other portion of the segment by another laser cut 109, which is preferably also continuous.

In other words, the track 112 and connector 111 may be formed entirely by laser cutting,

wherein in this embodiment said track 112 and connector 111 are formed by a first laser cut 107, forming a first boundary of the track 112 and connector 111, and a second laser cut 108, forming a second boundary of said track 112 and connector 111. It is imaginable that different separation techniques are utilized instead of laser cut 107 and 108. As long as the track 112 and connector 111 are locally separated from adjacent connectors 111 or tracks 112, at least electrically that is.

Although a local cut through the layer of conductive material 105 and optionally said conductive coating of the connection surface 104 may suffice for establishing electrical separation, it may be conceivable that the layer of conductive material 105 and conductive coating of the connection surface are removed over the entire connection surface, where no connector 111 or track 112 is to be formed.

Figure 1f shows an example where the returning cut 109 is also made, forming the first segment 110. Hence, the first segment boundary 106 and second segment boundary 109 together form the segment 110 which through its boundaries 106 and 109 is (electrically) separated from adjacent segments 110 to be formed by further first cuts 106’ and further second cuts 109’. As can be seen, the segments 110 do not necessarily have to be straight, but free shapes may be conceivable. This allows for increased design freedom in forming the segments 110 in the functional layer 102. The segmented functional layer 100 of figure 1f shows a total of three actively switchable segments 110, each comprising a dedicated segment connector 111 and a track 112 connected to the respective connector 111. The tracks 112 run towards an end portion 113 of the connection surface 104. At this end portion 1113, a flat printed circuit or the like may be connected to the respective tracks 112 such as to provide a power to a particular segment 110, via the track 112 and connector 111. Since all tracks 112, connectors 111, and segments 110 are electrically separated, it is possible to provide a power to a selective track 112, in order to switch or control a selective segment 110. Since the segments 110, connectors 111, and tracks 112 are formed by a single cut (forward cuts 106, 107, and returning cuts 108, 109) the connection between said portions (110, 111, 112) is made very accurate, and hence eliminates the need to align the segments 110 with aconnector 111. Such alignment is needed if the connectors 111 or tracks 112 are formed through a screen printing methodology.

Figure 2 shows a cross-section of a functional layer 200 according to the present invention. The cross-section of the functional layer 200 may correspond to the section A-A' indicated in figure 1b. The functional layer 200 indicated here comprises two thermoplastic layers 220, said thermoplastic layers being at a mutual distance and substantially parallel to each other. Mutually facing surfaces of said thermoplastic layers 220 are provided with a conductive coating 221, which may for example be an ITO coating 221. Arranged between the ITO coating 221 is afilm layer 222, which may be a liquid crystal, in particular being switchable though application of a power, in particular electric power. The right side of this functional layer 200 represents a connection surface 223, which connection surface 223 may be formed through local removal of material 225. The material that is removed is indicated by the dashed lines. That is, locally, in particular on the right side of the transition point 224, one thermoplastic layer 220 (the top one), the conductive coating 221 of said top thermoplastic layer 220, and the film layer 222 are removed.

Hence, the bottom thermoplastic layer 220 together with the conductive coating 221 applied on the inward facing surface of said bottom thermoplastic layer 220 form the connection surface 223.

Figure 3 indicates a functional layer 200 according to the present invention. The cross-section indicated in this figure may correspond to the cross-section B-B’ indicated in figure 1c. The functional layer 200 indicated here comprises two thermoplastic layers 220, said thermoplastic layers being at a mutual distance and substantially parallel to each other. Mutually facing surfaces of said thermoplastic layers 220 are provided with a conductive coating 221, which may for example be an ITO coating 221. Arranged between the ITO coating 221 is a film layer 222, which may be a liquid crystal, in particular being switchable though application of a power, in particular electric power. The right side of this functional layer 200 represents a connection surface 223, where locally material is removed. The removed material is preferably executed as indicated in figure 2. After removed of said material, a layer of conductive material 226 is provided onto at least a portion of the connection surface 223. In this embodiment the entire connection surface 223 is provide with said layer of conductive material 226. The layer of conductive material 226 may for example be a layer of silver 226. Said layer of conductive material 226 is in electrical contact with the conductive coating 221 of the connection surface 223. As such, applying a power, electrical power in particular, may allow to switch the functional layer 200, or a segment thereof via said layer of conductive material. As such, the present invention allows for simplified and more robust electrical connections to be established to the functional layer 200.

Figure 4 shows a top-view of a simplified segmented functional layer 300 according to an embodiment of the present invention. Here, two segments 310 are formed in the functional layer 302. Naturally, the number and shape of the segments 310 may be different. Here, each segment 310 comprises a specific segment connector 311, which segment connector is directly or indirectly electrically connected to the respective segment 310 in order to allow the segment to be switched, at least partially through the segment connector 311. The segment connector 311 on its turn is, at least electrically, connected to a track 312. Hence, applying an electric power to a track 312, powers the connector 311 connected to said track 312 and hence also the segment 310 connected to said connector 311 in order to switch said segment 310. In this embodiment, both connectors 311 are provided onto the connection surface 323, and also the tracks 312 are located on the connection surface 323. Preferably, said segments 310, connectors 311, tracks 312, and connection surface 323 are formed through the process indicated in figures 14-11.

This figure also indicates the width of the connectors 311, at least on the side facing the segments 310, is substantially equal to a width of the respective segment 210. On the end of the connector 311 facing away from the segment 310, the width is smaller, and debouches, or transitions into the track 312. That is, the track 312 and connector 311 form a substantially uniform composition of layers. Hence, no interruption may be conceived between a transition from connector 311 to track 312, which is a great benefit in terms of accuracy and robustness. That is, the tracks 312 are typically very narrow, which means that connecting a separate track 312 to a specific connector 311 requires great accuracy to prevent that the track is placed in a manner in which no electrical connection can be established, or worse, where it is connected to a wrong connector 311 which may cause short circuit.

Since the present invention allows the connector 311 and track 312 to be formed by a single layer, or two single layers, this accuracy issue is solved. Hence, the connector 311 smoothly, in particular uninterruptedly transitions into the track 312.

Figures 5i-5iii show different details of the cross-sections along lines C-C’, D-D’, and E-E’ respectively indicated in figure 4. Figure 5i shows the cross section along line C-C’ in figure 4. In figure 5i, the conductive coating 321 on the thermoplastic layers 320 of the sheet structure are not indicated for illustrative purposes, however, they are provided on the inward facing surfaces of the thermoplastic layers 320. The connection surface 323 of the segmented functional layer 300 shows the layer of conductive material 326 provided onto the connection surface 323, in particular on the conductive coating 321 (not shown) of the thermoplastic layer 320 forming said connection surface 323. Here, the cross section shows the connector 311 as indicated in figure 4. The connector 311 is electrically separated from the remaining portion 328 of the connection surface. Here, the separation is formed by means of a local removal of material 327. The local removal 327 locally separates (physically) the layer of conductive material 326 and preferably the conductive coating 321. Hence, no electric connection is present between the connector 311 and the remaining portion 328 in this cross section. lt is also conceivable that the remaining portion 327 is fully removed, such that merely the connector 311 remains. Figure 5ii shows a cross-section of the segmented functional layer 300 along line D-D’ in figure 4. The cross section D-D’ is in the same direction as the one shown in C-C’, but on a different location of the segmented functional layer 300. Figure 5ii shows the connection surface 323,

where again a connector 311 is indicated, which is the connector to the other segment 310 of the segmented functional layer 300. This cross section D-D’ is taken at a different point of the connector 311. Also a cross-section of the track 312a of the connector 311 is indicated, as well as the track 312b which is connected to the other connector 311 (the one seen in figure 5i). between the connector 311 and the tracks 312a, 312b, the remaining material is removed forming separations 329.

Figure 6 shows an automotive window laminate 400 comprising a segmented functional layer 401 according to the present invention. Two sheets of glass 404 are provided, mutually parallel and at a distance, wherein the segmented functional layer 401 comprising the sheet structure 403 is provided between said sheets of glass 404. The segmented functional layer 401 is also provided between a pair of bonding layers 402. The bonding layers 402 being arranged against the glass sheets 404. At the perimeter of the functional layer 401 it is conceivable that a frame, or encapsulation layer 413 is placed. Although, it is also conceivable the encapsulation layer is formed by an inactive portion of the functional layer 401, such that said encapsulation layer 413 is integral part of the functional layer 401.

Here, the functional layer comprises a sheet structure 403 with two thermoplastic layers 405, mutually facing sides of said thermoplastic layers being provided with a conductive coating 407. Between the conductive coating the film layer 407, in particular the switchable film layer 407 is arranged. Along one edge the connection surface 408 is formed by one of the thermoplastic layers 405 that extends beyond the other thermoplastic layer 405 and the film layer 407. On top of the conductive coating 406 of the thermoplastic layer 405 forming the connection surface 408 a conductive material 426 is provided. The conductive material is electrically separated along two cuts 428. As such, a connector 411 for one segment is formed, and a pair of tracks 412, each for electrically connecting a connector 411 to a power source.

The above-described inventive concepts are illustrated by several illustrative embodiments. It is conceivable that individual inventive concepts, including inventive details, may be applied without, in so doing, also applying other details of the described embodiments. It is not necessary to elaborate on examples of all conceivable combinations of the above-described inventive concepts, as a person skilled in the art will understand numerous inventive concepts can be (re)combined in order to arrive at a specific application and/or alternative embodiment.

The ordinal numbers used in this document, like “first”, “second”, and “third” are used only for identification purposes. Hence, the use of expressions like a “second” component, does therefore not necessarily require the co-presence of a “first” component. By "complementary" components is meant that these components are configured to co-act with each other. However, to this end, these components do not necessarily have to have complementary forms. The verb “comprise” and conjugations thereof used in this patent publication are understood to mean not only “comprise”, but are also understood to mean the phrases “contain”, “substantially consist of”, “formed by” and conjugations thereof.

Claims

Conclusions

1. Method for segmenting a functional sheet structure for an automobile, comprising the steps of: A) obtaining at least one sheet structure, the at least one sheet structure comprising at least two thermoplastic layers, wherein mutually facing sides of the thermoplastic layers are provided with a conductive coating, and at least one, preferably switchable, film layer disposed between the at least two thermoplastic layers, the sheet structure further comprising at least one connecting surface for electrically connecting the sheet structure to a power source; B) forming at least two, mutually electrically separated, segments in the at least one sheet structure, preferably by locally removing at least one thermoplastic layer with conductive coating, and optionally the film layer; C) forming at least two, mutually electrically separated, segment connectors on the connecting surface, wherein the at least two segment connectors are formed by locally removing conductive coating on the connecting surface.

2. The method of claim 1, further comprising the step of: D) providing a layer of conductive material on at least a portion of the bonding surface, said layer of conductive material being in contact with the conductive coating of at least one thermoplastic layer of the sheet structure.

3. The method of claim 2, wherein during step C, the segment connectors are formed by locally removing at least a portion of the conductive material provided in step D) and the conductive coating from the thermoplastic layer.

4. A method according to any preceding claim, further comprising the step of removing a portion of at least one thermoplastic layer and a portion of the film layer, at least along a portion of at least one edge of the sheet structure.

5. Method according to any one of the preceding claims, wherein at least one segment and/or at least one segment connector is formed during step B) and/or step C) by means of laser cutting.

6. The method of claim 5, wherein a laser power is adjusted when the laser cut transitions from the segment to the segment connector.

7. Method according to any one of the preceding claims, wherein at least one segment and at least one respective segment connector are formed by means of a continuous step, in particular by means of a continuous laser cut, preferably single continuous laser cut.

8. A method according to any preceding claim, further comprising the step of: E) providing at least two electrically conductive tracks on the connecting surface, each electrically conductive track being electrically connected to at least one segment connector.

9. The method of claim 8, wherein the at least two electrically conductive paths and the at least two segment connectors are disposed adjacent to a single edge of the sheet structure.

10. Method according to any one of claims 2 to 9, wherein during step C) the at least two segment connectors, and optionally the at least two paths provided during step E), are formed by simultaneously removing the conductive coating from the thermoplastic layer and providing a layer of conductive material on said conductive coating.

11. Segmented functional layer for use in a laminate structure of automotive windows, the functional layer comprising: - At least one sheet structure, comprising o at least two thermoplastic layers, wherein facing sides are provided with a conductive coating, o at least one, preferably switchable, film layer applied between the at least two thermoplastic layers,

o wherein said sheet structure, in particular the at least one film, is divided into at least two segments; - at least one connecting surface, formed by a part of one of the at least two thermoplastic layers, comprising; o at least two electrically separated segment connectors, each for connecting a segment to a power source, at least one, preferably each, segment connector being formed by an area of conductive material provided on the conductive coating of the thermoplastic layer forming the connecting surface.

12. The segmented functional layer of claim 11, wherein said region of conductive material and the conductive coating of the thermoplastic layer have substantially coincident edges.

13. Segmented functional layer according to claim 11 or 12, wherein at least one, preferably each, segment connector is electrically connected to at least one electrically conductive path, said electrically conductive path being provided on the at least one connecting surface.

14. The segmented functional layer of claim 13, wherein the least one path is formed by a region of conductive material provided on the conductive coating of the thermoplastic layer forming the bonding surface.

15. The segmented functional layer of claim 14, wherein both the at least one segment connector and the at least one path are formed by the same and/or continuous area of conductive material.

16. Segmented functional layer according to any one of claims 11 to 15, comprising at least one thermoplastic cover layer, said thermoplastic cover layer covering at least one connector and/or conductive track, in particular wherein the thermoplastic cover layer at least partially overlaps with the thermoplastic layer of the at least one sheet structure.

17. A segmented functional layer according to any one of claims 11 to 16, wherein at least a portion of at least one bonding surface is formed by a portion of at least one thermoplastic layer extending beyond the periphery of the other thermoplastic layer and/or film layer.

18. Segmented functional layer according to any of claims 11 to 17, wherein a width of a part of at least one segment connector substantially corresponds to a width of the respective segment of the plate structure.

19. The segmented functional layer of claim 18, wherein the width of the at least one segment connector decreases in width, at least viewed in the direction from the side connected to the respective segment towards a side connected to a web.

20. The segmented functional layer of any one of claims 11 to 19, wherein at least one segment, and at least one segment connector, and at least one connector path, are formed from a single continuous laser cut, said laser cut electrically separating said segment, segment connector, and connector path from any other segments, segment connectors, and connector paths.

21. Laminated structure for automotive windows, comprising: - a first glass sheet, and a second glass sheet, said first and second glass sheets being positioned parallel and spaced apart from each other, - at least one laminated thermoplastic sheet structure, said laminated thermoplastic sheet structure being disposed substantially in its entirety between the first and second glass sheets, said laminated sheet structure comprising; - at least one segmented functional layer, in particular a segmented functional layer according to any one of claims 10 to 20, having an upper and lower surface, - at least two adhesive layers, said at least two adhesive layers covering substantially the entire upper and lower surfaces of said at least one functional layer, a portion of said adhesive layers extending beyond a portion of the periphery of said functional layer.

22. Laminate structure for automotive windows according to claim 21, wherein at least one segment connector of the segmented functional layer is at least partially sealed by at least one adhesive layer of the laminated thermoplastic sheet structure.

23. Transport vehicle, such as a car, bus or a truck, provided with a laminate structure for an automotive window according to any of the preceding claims.