COMPOSITE PANE WITH A FUNCTIONAL ELEMENT HAVING ELECTRICALLY CONTROLLABLE OPTICAL PROPERTIES WITH IMPROVED EDGE SEALING

Abstract

A composite pane containing a functional element having electrically controllable optical properties includes, in this order, a first pane, a first thermoplastic composite film having at least one plasticizer, a functional element having a peripheral edge, a barrier film having a cutout, into which the functional element is inserted, a second thermoplastic composite film having at least one plasticizer, a second pane, wherein the barrier film surrounds the functional element in a frame-like manner and is in direct contact with the peripheral edge of the functional element, and the barrier film contains at most 0.5 wt.-% plasticizer and prevents the diffusion of plasticizer through the barrier film.

Claims

1. A composite pane containing a functional element having electrically controllable optical properties comprising, in this order a first pane, a first thermoplastic composite film having at least one plasticizer, a functional element having a peripheral edge, a barrier film having a cutout, into which the functional element is inserted, a second thermoplastic composite film having at least one plasticizer, a second pane, wherein the barrier film surrounds the functional element in a frame-like manner and is in direct contact with the peripheral edge of the functional element, and the barrier film contains at most 0.5 wt.-% plasticizer and prevents the diffusion of plasticizer through the barrier film.

2. The composite pane according to claim 1, wherein the functional element is a polymer dispersed liquid crystal (PDLC) film.

3. The composite pane according to claim 1, wherein a thickness of the barrier film and a thickness of the functional element differ from one another by at most 30%, and the thickness of the barrier film and the thickness of the functional element are substantially the same.

4. The composite pane according to claim 1, wherein the barrier film has a thickness of 0.1 mm to 1.0 mm.

5. The composite pane according to claim 1, wherein the first and/or the second thermoplastic composite film contains at least 3 wt. % of a plasticizer, and the plasticizer contains or is made of aliphatic diesters of tri- or tetraethylene glycol.

6. The composite pane according to claim 1, wherein the thermoplastic composite films contain at least 60 wt. % of polyvinyl butyral (PVB).

7. The composite pane according to claim 1, wherein the barrier film contains or is made of polyethylene terephthalate PET) or polyvinyl fluoride (PVF) and is plasticizer free.

8. The composite pane according to claim 1, wherein the material composition of the barrier film differs in terms of its main constituent by weight from the main constituent by weight of the thermoplastic composite films.

9. The composite pane according to claim 8, wherein the barrier film contains polyethylene terephthalate (PET) as the main constituent by weight and the thermoplastic composite films contain polyvinyl butyral (PVB) as the main constituent by weight.

10. The composite pane according to claim 1, wherein the barrier film in the form of a pre-composite comprising a barrier film and a first thermoplastic composite film or in the form of a pre-composite comprising a barrier film and a second thermoplastic composite film is inserted into the layer stack of the composite pane and the barrier film is in direct contact with the thermoplastic composite film of the pre-composite.

11. A method for producing a composite pane with a functional element according to claim 1, the method comprising: arranging a first thermoplastic composite film sheet-wise on a first pane, arranging a functional element and a barrier film surrounding the peripheral edge of the functional element in a frame-like manner on the first thermoplastic composite film, arranging a second thermoplastic composite film on the functional element and the barrier film, placing a second pane placed on the second thermoplastic composite film, and bonding the layer stack by autoclaving to form a composite pane, wherein the barrier film contains at most 0.5 wt.-% plasticizer and prevents the diffusion of plasticizer through the barrier film, and the first thermoplastic composite film and the second thermoplastic composite film contain in each case at least one plasticizer.

12. The method according to claim 11, wherein the barrier film is inserted into the layer stack as a pre-composite together with the first thermoplastic composite film or the second thermoplastic composite film.

13. The method according to claim 12, wherein the barrier film is bonded to the first thermoplastic composite film or the second thermoplastic composite film under the action of heat and pressure to form a pre-composite.

14. The method according to claim 12, wherein a pre-composite is created from a substantially congruently arranged thermoplastic composite film and a barrier film, the barrier film of the pre-composite is removed in at least one cutout, and during assembly of the layer stack, the functional element is inserted into the cutout of the barrier film.

15. A method comprising utilizing a composite pane according to claim 1 as a windshield or roof panel of a vehicle, wherein the electrically controllable functional element serves as a sun visor or as a privacy screen.

16. The composite pane according to claim 3, wherein the thickness of the barrier film and the thickness of the functional element differ from one another by at most 20%.

17. The composite pane according to claim 4, wherein the barrier film has a thickness of 0.3 mm to 0.5 mm.

18. The composite pane according to claim 5, wherein the first and/or the second thermoplastic composite film contains at least 30 wt.-% of a plasticizer.

19. The composite pane according to claim 5, wherein the plasticizer contains or is made of triethylene glycol-bis-(2-ethyl hexanoate).

20. The composite pane according to claim 6, wherein the thermoplastic composite films contain at least 90 wt.-% of polyvinyl butyral (PVB).

Description

[0097] The invention is explained in detail with reference to drawings and exemplary embodiments. The drawings are schematic representations and not to scale. The drawings in no way restrict the invention. They depict:

[0098] FIG. 1a a cross-section of a pre-composite comprising a barrier film and a thermoplastic composite film during the cutting of the film to size,

[0099] FIG. 1b a layer stack of an embodiment of the composite pane according to the invention prior to lamination of the pane,

[0100] FIG. 2a a plan view of an embodiment of the composite pane according to the invention,

[0101] FIG. 2b a cross-section through the composite pane of FIG. 2a along the section line A-A,

[0102] FIG. 2c an enlarged representation of the region Z of FIG. 2b,

[0103] FIG. 3a a plan view of another embodiment of a composite pane according to the invention as a roof panel with a functional element,

[0104] FIG. 3b a cross-section through the composite pane of FIG. 5a along the section line B-B,

[0105] FIG. 4a a plan view of another embodiment of a composite pane according to the invention as a windshield with a sun visor,

[0106] FIG. 4b a cross-section through the composite pane of FIG. 5a along the section line B-B,

[0107] FIG. 5 an exemplary embodiment of the method according to the invention using a flowchart.

[0108] FIG. 1 a depicts a pre-composite 9 according to the invention comprising a thermoplastic composite film 3 or 4 and a barrier film 6 and the processing steps for cutting the barrier film 6 to size, represented as states A to C. This can be a composite 9 of the first thermoplastic composite film 3 with the barrier film 6, or a composite 9 of the second thermoplastic composite film 4 with the second barrier film 6. The pre-composite 9 per state A) in FIG. 1a was produced by routing a thermoplastic composite film 3 or 4 together with a barrier film 6 through a heated pair of rollers with a temperature of 45 C. and a speed of 4 m/min. The rollers press the films together under heating, bonding them to form a pre-composite. The thermoplastic composite film 3 or 4 is made of 78 wt.-% polyvinyl butyral (PVB) and 20 wt.-% triethylene glycol bis(2-ethyl hexanoate) as plasticizer and have in each case a thickness of 0.38 mm, while the barrier film 6 is made substantially of polyethylene terephthalate (PET) and is 400 m thick. Here, the barrier film 6 is made, for example, substantially of PET, i.e., at a rate of at least 97 wt.-%. The barrier film 6 contains less than 0.5 wt.-% plasticizer and is preferably plasticizer-free. The barrier film 6 is suitable to decisively reduce or prevent the diffusion of plasticizer out of the thermoplastic composite films 3, 4. In such a pre-composite 9, cuts 18 are made in the barrier film 6 of the pre-composite 9 using a cutting tool 17. The cutting depth is selected such that the thermoplastic composite film 3 or 4 remains substantially undamaged. The cuts 18 made in the barrier film 6 produce a cutout 7 in the surface of the barrier film 6. The barrier film remains only in the form of a peripheral frame in the edge region of the later composite pane. At the location where the cuts 18 were made, an inner edge 22 of the barrier film results.

[0109] Suitable cutting tools 17 are known to the person skilled in the art. A plotter equipped with a cutting blade has, for example, proved to be quite suitable. However, other methods can also be used, such as laser cutting. The barrier film 6 is removed in the region of the cutout 7. This is possible by lifting the barrier film 6 to be detached at the edge of a cut 18. Starting from such a raised corner, the regions of the barrier film 7 to be removed are peeled off. This is possible with morate expenditure of force and without damaging the films. The inner edge 22 of the barrier film 6 extends, set back inward relative to the outer edge of the subsequent composite pane, in the direction of the center of the barrier film 6. The inner edge 22 runs peripherally and forms a passe-partout, into which a functional element can be inserted. The amount by which the inner edge 22 is set back relative to the subsequent outer edge of the composite pane in the direction of the center of the pane can be variable or constant along the peripheral edge. This variability is made possible above all by the use of a pre-composite, which enables a substantially more precise positioning of the films in the layer stack. A pre-composite 9 is created comprising a continuous thermoplastic composite film 3 or 4 and a frame-like barrier film 6, which is present only at the points of the pre-composite where it is required for the sealing of the functional element (see C) in FIG. 1a). A single barrier film 6 cut like a frame has only low dimensional stability such that it cannot be handled by machine and can hardly be handled manually. By using a bilayer (pre-composite 9) according to the invention, the barrier film 6 can be cut in any desired geometries without restrictions. The stability and manageability of the arrangement is always ensured by the thermoplastic composite film 3 or 4. Accordingly, the use of bilayers is crucial to the automation of the process and to the variable shaping of the functional element.

[0110] FIG. 1b depicts a layer stack for producing the composite pane according to the invention using the pre-composite per FIG. 1a. The plus signs situated between the plies of the layer stack indicate the layer sequence in which the components are arranged on one another. A first thermoplastic composite film 3 is placed on a first pane 1 made of a clear soda lime glass with a thickness of 1.6 mm. The first pane 1 per FIG. 1b represents the inner pane of the windshield of a motor vehicle. A functional element 5 is placed on the first thermoplastic composite film 3. The functional element is implemented as a PDLC element with a thickness of 400 m. A bilayer (pre-composite 9 per FIG. 1a) which comprises a second thermoplastic composite film 4 and a barrier film 6 and which points with the barrier film 4 in the direction of the functional element 5 is applied on the functional element 5. The barrier film 6 and the functional element 5 are coordinated with one another in their dimensioning such that the peripheral edge 8 of the functional element 5 is enclosed in a frame-like manner by the inner edge 22 of the barrier film 6. The inner edge 22 of the barrier film 6 and the peripheral edge 8 of the functional element 5 are in direct contact after assembly and autoclaving of the layer stack to form a composite pane. The barrier film 6 has a thickness of 400 m and thus completely covers the edge 8 of the functional element. Since the functional element and the barrier film 6 have substantially the same thickness (400 m), there is not only good edge sealing of the functional element 5, but also good thickness compensation via the barrier film 6. A second pane 2 is placed above the second thermoplastic composite film 4, completing the layer stack. The second pane 2 has a thickness of 2.1 mm and and is also made, for example, of a clear soda lime glass. In this case, the second pane 2 is the outer pane of the windshield and is bent congruently together with the first pane.

[0111] The barrier film 6 is trimmed per FIG. 1a such that it is suitable in its dimensions to surround the peripheral edge 8 of the functional element 5 per FIG. 1b. Any other films, for example functional films or colored films can be arranged between the first thermoplastic composite film 3 and the first pane 1 or between the second thermoplastic composite film 4 and the second pane 2. The pre-composite 9 remains in the vicinity of the functional element 5 with direct contact between the functional element 5 and the barrier film 6, even if the layer stack is expanded. Such a layer stack can be machine assembled. The use of pre-composites thus represents a significant simplification in terms of the production method of the composite pane. As an alternative to the composite pane described in FIG. 1b, a pre-composite 9 comprising a first thermoplastic composite film 3 and a barrier film 6 can be used analogously.

[0112] FIG. 2a depicts an embodiment of a composite pane 100 according to the invention comprising a first pane 1, a second pane 2, a first thermoplastic composite film 3, a second thermoplastic composite film 4, a barrier layer 6 and a functional element 5. FIG. 2b depicts a cross-section of the composite pane per FIG. 2a along the section line A-A. An enlargement of the region Z of FIG. 2b is presented in FIG. 2c. The composite pane 100 can, for example, be arranged as an architectural glazing in the frame of a window with additional panes to form an insulating glazing unit. The first and the second pane 1, 2 are made of clear soda lime glass with a thickness 2.0 mm in each case. The first pane 1 and the second pane 2 are joined to one another via the first thermoplastic composite film 3 and the second thermoplastic composite film 4. A functional element 5, which is also bonded to the panes 1, 2 via the thermoplastic composite films 3, 4, is inserted between the first thermoplastic composite film 3 and the second thermoplastic composite film 4. A barrier film 6, which encloses the peripheral edge 8, is arranged along the peripheral edge 8 of the functional element. Since the peripheral edge 8 of the functional element 5 is completely enclosed by the barrier film 6, in aging tests, the composite pane 100 with the functional element 5 shows either no brightening or hardly any visually perceptible brightening in the edge region of the functional element 5. According to the invention, diffusion of the plasticizer out of the thermoplastic composite film 3, 4 into the functional element 5 and degradation of the functional element 5 associated therewith are avoided. Furthermore, the barrier film 6 serves for thickness compensation between the region of the pane with the functional element 5 and the region of the pane without the functional element 5. An additional thermoplastic frame film is therefore not required.

[0113] The optical properties of the functional element 5 can be controlled by applying an electrical voltage. For the sake of simplicity, the electrical supply lines are not shown.

[0114] The controllable functional element 5 is, for example, a PDLC multilayer film, consisting of an active layer 11 between two surface electrodes 12, 13 and two carrier films 14, 15. The active layer 11 contains a polymer matrix with liquid crystals dispersed therein, which align themselves as a function of the electrical voltage applied on the surface electrodes, by which means the optical properties can be controlled. The carrier films 14, 15 are made of PET and have a thickness of, for example, 180 m. The carrier films 14, 15 are provided with a coating of ITO facing the active layer 11 and having a thickness of approx. 100 nm, forming the surface electrodes 12, 13. The surface electrodes 12, 13 can be connected to a voltage source via bus bars (not shown) (implemented, for example, by a silver-containing screen print) and connecting cables (not shown).

[0115] The thermoplastic composite films 3, 4 comprise in each case a thermoplastic film with a thickness of 0.38 mm and are made, for example, of 78 wt.-% polyvinyl butyral (PVB) and 20 wt.-% triethylene glycol bis(2-ethyl hexanoate) as a plasticizer.

[0116] The barrier film 6 is made, here, for example, substantially of PET, i.e., at a rate of at least 97 wt.-%. The barrier film 6 contains less than 0.5 wt.-% plasticizer and is suitable for preventing the diffusion of plasticizer out of the thermoplastic composite layers 3, 4 via the peripheral edge 8 into the functional layer 5.

[0117] The barrier film 6 has a thickness of 450 m, whereas the functional element has a thickness of 400 m. Since the thickness of the barrier film 6 exceeds the thickness of the functional element 5, the inner edge 22 of the barrier film completely covers the peripheral edge of the functional element.

[0118] The barrier film 6 is in direct contact with the functional element 5, in the present case by direct contact with the open cross-section of the functional element 5 along the peripheral edge 8. The barrier film 6 has no overlap at all in the form of a contact of the film surfaces, but rather enables deliberate selective edge sealing through direct contact of the side edges. In this context, film surfaces refers to the surfaces of the films running substantially parallel to the panes 1, 2, while the film edges have a course essentially orthogonal to the panes 1, 2. Here, direct contact means that no further components or chemical compounds at all, for example, adhesives, are arranged between the barrier film 6 and the functional element 5. According to the prior art, slippage of the barrier films during assembly is prevented by adhesive connections. According to the invention, an adhesive connection is unnecessary and undesirable. Slippage of the barrier films is achieved through the use of the pre-composite 9, which comprises the barrier film 6 and one of the thermoplastic composite films 3 or 4. The embodiment of the invention described in FIGS. 2a, 2b, and 2c includes a pre-composite 6 produced per FIG. 1a. The use of pre-composites ensures not only a shifting of the barrier film in the layer stack, but also facilitates the assembly of the layer stack. At the same time, inclusion of air bubbles and resultant optical disturbances or impairments are avoided since the barrier film 6 lies evenly at the peripheral edge of the functional element 5. The barrier film 6 according to the invention is firmly fixed in the region of the peripheral edge 8 of the functional element 5 by the internal pressure in the finished laminated composite pane 100 and pressed against the adjacent film components, resulting in a hermetic seal even without the use of adhesives. This was unexpected and surprising for the person skilled in the art.

[0119] FIG. 3a depicts a plan view of an embodiment according to the invention of a composite pane 100 as a roof panel of a motor vehicle. FIG. 3b depicts a cross-section of the roof panel per FIG. 3a along the section line BB. The roof panel comprises a first pane 1, a second pane 2, a first thermoplastic composite film 3, a second thermoplastic composite film 4, a barrier layer 6, and a functional element 5. The first and the second pane 1, 2 are bent congruently with one another. The second pane 2 is the outer pane of the glazing, in other words, it is oriented toward the vehicle's surroundings, whereas the first pane 1 is the inner pane of the composite pane is and points toward the vehicle interior. The second pane 2 is made of clear soda lime glass with a thickness of 2.1 mm. The first pane 1 is made of soda lime glass with a thickness of 1.6 mm and is tinted gray. The tinted inner glass contributes to the attractive appearance of the pane, even for the vehicle occupant when looking through the roof panel. The first pane 1 and the second pane 2 are joined to one another via the first thermoplastic composite film 3, the second thermoplastic composite film 4, and an additional thermoplastic composite film 19. A functional element 5 that is likewise bonded to the panes 1, 2 via the thermoplastic composite films 3, 4 is inserted between the first thermoplastic composite film 3 and the second thermoplastic composite film 4. A first barrier film 6 that encloses the peripheral edge 8 is arranged along the peripheral edge 8 of the functional element. For this purpose, the barrier film 6 rests along the peripheral edge 8 of the functional element 5 directly at this edge. Thus, the peripheral edge 8 of the functional element 5 is completely closed and sealed by the barrier film 6. The composite pane 100 with the functional element 5 shows, in aging tests, either no or hardly any visually perceptible brightening in the edge region of the functional element 5. According to the invention, diffusion of the plasticizer out of the thermoplastic composite films 3a, 4a into the functional element 5 and degradation of the functional element 5 associated therewith are avoided. The first thermoplastic composite film 3 and the second thermoplastic composite film 4 are tinted gray to make the appearance of the pane attractive. The additional thermoplastic composite film 19 is colorless and is attached adjacent the outer pane (second pane 2). The additional thermoplastic composite film 19 serves to incorporate an additional carrier film 20 having an infrared reflecting coating 21 into the layer stack. The additional carrier film 20 is a PET film with a thickness of 50 m, that is attached between the additional thermoplastic composite film 19 and the second thermoplastic composite film 4. The infrared reflecting coating 21 is oriented in the direction of the second pane 2 (outer pane) and is used to reduce heating of the passenger compartment by solar radiation.

[0120] The optical properties of the functional element 5 can be controlled by applying an electrical voltage. For the sake of simplicity, the electrical supply lines are not shown. The controllable functional element 5 is, for example, a PDLC multilayer film, comprising an active layer 11 between two surface electrodes 12, 13 and two carrier films 14, 15. The further structure of the functional element corresponds to that described in FIG. 2a-2c.

[0121] The thermoplastic composite films 3, 4 and the barrier film 6 correspond in their chemical composition and their layer thickness to the dimensions described in FIG. 2a-2c. Here, the barrier film 6 also ensures thickness compensation between the regions with and without the functional element 5 such that an additional thermoplastic frame film is, consequently, unnecessary.

[0122] The edge region of the roof panel is concealed by a circumferential black print 10 (circumferential peripheral masking print) that is applied at least on the inner side of the outer pane. The black print is formed by printing an opaque enamel onto the interior-side surface (facing the interior of the vehicle in the installed position) of the second pane 2. Optionally, a black print 10 can also be applied on the inner side of the first pane 1. The peripheral edge 8 of the functional element 5 lies in the region of the black print 10 such that it is not perceptible when viewing the roof panel from the outside. The distance of the functional element 5 from the peripheral edge of the roof panel is thus smaller than the width of the black print 10. The electrical connections (not shown) are also reasonably mounted in the region of the black print 10 and thus hidden.

[0123] The barrier film 6 is in direct contact with the functional element 5, in the present case, in sheet-wise contact with the surfaces of the carrier films 14, 15, and, additionally, in direct contact with the open cross-section of the functional element 5 along the peripheral edge 8. Also, according to the exemplary embodiment of FIGS. 3a and 3b, no adhesive or other adhesion-promoting substances at all are used; instead, the barrier film 6 is used as pre-composites 9 per FIGS. 1a and 1b with one of the thermoplastic composite films 3, 4. The barrier film 6 according to the invention in the region of the peripheral edge 8 of the functional element 5 is firmly fixed there by the inner pressure in the finished laminated composite pane 100 and pressed against the adjacent film, as a result of which hermetic sealing occurs even without the use of adhesives. This was unexpected and surprising for the person skilled in the art.

[0124] FIG. 4a depicts a plan view of another embodiment of a composite pane 100 according to the invention as a windshield with an electrically controllable sun visor. The PDLC functional element 5 is divided by horizontal isolation lines 16 into six strip-like segments. The isolation lines 16 have, for example, a width of 40 m to 80 m and are spaced 3.5 cm apart. They were introduced into the prefabricated multilayer film by laser. The isolation lines 16 separate, in particular, the electrodes 12, 13 into strips isolated from one another, which have, in each case, a separate electrical connection. The segments can thus be switched independently of one another. The thinner the isolation lines 16, the less conspicuous they are. Even thinner isolation lines 16 can be realized by etching.

[0125] The height of the darkened functional element 5 can be adjusted by the segmentation. Thus, depending on the position of the sun, the driver can darken the entire sun visor or even only part of it. The figure indicates that the upper half of the sun visor is darkened and the lower half is transparent.

[0126] In a particularly convenient embodiment, the functional element 5 is controlled by a capacitive switch area arranged in the region of the functional element, wherein the driver determines the degree of darkening by the location at which he touches the pane.

[0127] The windshield per FIGS. 4a and 4b comprises a trapezoidal composite 100 with a first pane 1 as an inner pane and a second pane 2 as an outer pane that are joined to one another via two thermoplastic composite films 3, 4. The second pane 2 has a thickness of 2.1 mm and is made of a green-colored soda lime glass. The first pane 1 has a thickness of 1.6 mm and is made of a clear soda lime glass. The windshield has an upper edge D facing the roof in the installed position and a lower edge M facing the engine compartment in the installed position. The cross-section of the composite pane 100 is shown in detail in FIG. 4b. This corresponds substantially to the structure per FIG. 3b. However, in deviation therefrom, an additional thermoplastic composite film 19 is inserted outside the region in which the functional element 5 is inserted in the composite pane 100. This additional composite film 19 borders laterally on the barrier film 6 that serves to seal the functional element. In this case, the thickness compensation between regions with and without the functional element is done via the barrier film 6 and the additional thermoplastic composite film 19 arranged adjacent it.

[0128] The sun visor is formed by a commercially available PDLC multilayer film as the functional element 5 that is embedded in the plastic composite films. The height of the sun visor b is, for example, 21 cm. The first thermoplastic composite film 3 is bonded to the first pane 1; the second thermoplastic composite film 4 is bonded to the second pane 2. In the region of the peripheral edge 8 of the functional element 5, a barrier film 6 that surrounds the edge 8 and seals the functional element 5 is inserted into the layer stack. The barrier film 6 is used as a pre-composite 9 with the second thermoplastic composite film 4.

[0129] The second thermoplastic composite film 4 has a tinted region that is arranged between the functional element 5 and the second pane 2 (outer pane). The light transmittance of the windshield is thus additionally reduced in the region of the functional element 5, and the milky appearance of the PDLC functional element 5 in the diffuse state is mitigated. The aesthetics of the windshield are thus significantly more attractive. The second thermoplastic composite film 4 has, in the tinted region, for example, average light transmittance of 30%, with which good results are achieved. The region can be homogeneously tinted. However, it is often visually more appealing if the tinting decreases in the direction of the lower edge of the functional element 5 such that the tinted and the non-tinted regions merge smoothly.

[0130] The lower edge of the tinted region and the lower edge of the PDLC functional element 5 can be arranged flush with one another. This is, however, not necessarily the case. It is also possible for the tinted region to protrude beyond the functional element 5 or, vice versa, for the functional element 5 to protrude beyond the tinted region. In the latter case, it would not be the entire functional element 5 that would be bonded to the second pane 2 via the tinted region.

[0131] The controllable functional element 5 is a multilayer film, analogous to the structure depicted in FIG. 2c, consisting of an active layer 11 between two surface electrodes 12, 13 and two carrier films 14, 15. The active layer 11 contains a polymer matrix with liquid crystals dispersed therein, which align themselves as a function of the electrical voltage applied to the surface electrodes, as a result of which the optical properties can be controlled. The carrier films 14, 15 are made of PET and have a thickness of, for example, 0.125 mm. The carrier films 14, 15 are provided with a coating of ITO facing the active layer 11 and having a thickness of approx. 100 nm, forming the electrodes 12, 13. The electrodes 12, 13 can be connected to the vehicle's electrical system, via busbars (not shown) (formed, for example, by a silver-containing screen print) and via connecting cables (not shown).

[0132] A so-called high flow PVB, which has stronger flow behavior compared to standard PVB films, can preferably be used for the thermoplastic composite films 3, 4, 19 per FIGS. 1 to 4. The layers thus flow around the barrier film 6 and the functional element 5 more strongly, creating a more homogeneous visual impression, and the transition from the functional element 5 to the composite films is less conspicuous. The high flow PVB can be used for all or even for only one or more of the thermoplastic composite films 3, 4, 19.

[0133] FIG. 5 depicts an exemplary embodiment of the method according to the invention comprising the steps: [0134] Ia Producing a pre-composite 9 comprising a first thermoplastic composite film 3 and a barrier film 6 [0135] or [0136] Ib Producing a pre-composite 9 comprising a second thermoplastic composite film 4 and a barrier film 6 [0137] II Creating a cutout 7 in the barrier film 6 of the pre-composite 9, wherein the barrier film 6 is removed within the cutout 7 [0138] III Providing a first pane 1 [0139] IVa Placing the pre-composite 9 comprising the first thermoplastic composite film 3 and the barrier film 6 on the first pane 1, wherein the first thermoplastic composite film 3 is applied in the vicinity of the first pane 1 [0140] or [0141] IVb Placing a first thermoplastic composite film 3 on the first pane 1 [0142] Va Inserting a functional element 5 in the cutout 7 of the barrier film 6, wherein the barrier film 6 encloses the peripheral edge 8 of the functional element 5 [0143] or [0144] Vb Placing a functional element 5 on the first thermoplastic composite film 3

[0145] VIa Placing a second thermoplastic composite film 4 on the barrier film 6 and the functional element 5 [0146] or [0147] VIb Placing the pre-composite 9 comprising the second thermoplastic composite film 4 and the barrier film 6 on the functional element 5, wherein the barrier film 6 is applied in the vicinity of the functional element and encloses the peripheral edge 8 of the functional element 5 [0148] VII Placing a second pane 2 on the second thermoplastic composite film 4 [0149] VIII Autoclaving the layer stack to form a composite pane 100

LIST OF REFERENCE CHARACTERS

[0150] 1 first pane [0151] 2 second pane [0152] 3 first thermoplastic composite film [0153] 4 second thermoplastic composite film [0154] 5 functional element having electrically controllable optical properties [0155] 6 barrier film [0156] 7 cutout (of the barrier film) [0157] 8 peripheral edge of the functional element 5 [0158] 9 pre-composite comprising first thermoplastic composite film 3 or second thermoplastic composite film 4 and barrier film 6 [0159] 10 black print [0160] 11 active layer of the functional element 5 [0161] 12 first surface electrode of the functional element 5 [0162] 13 second surface electrode of the functional element 5 [0163] 14 first carrier film [0164] 15 second carrier film [0165] 16 isolation lines [0166] 17 cutting tool [0167] 18 cuts [0168] 19 additional thermoplastic composite films [0169] 20 additional carrier film [0170] 21 infrared reflecting coating [0171] 22 inner edge of the barrier film 6 [0172] 100 composite pane [0173] AA, BB, CC section lines [0174] Z enlarged region [0175] S field of vision B [0176] M engine edge [0177] D roof edge