COMPOSITE PANE WITH A CAPACITIVE SWITCHING ZONE

Abstract

A composite pane with a capacitive switching zone includes a substrate, a first intermediate layer areally bonded to the substrate, a second intermediate layer areally bonded to the first intermediate layer, and a cover pane areally bonded to the second intermediate layer. A carrier film with an electrically conductive layer is arranged between the first and second intermediate layers. A capacitive switching zone is electrically isolated from the electrically conductive layer by a coating-free separating line, the capacitive switching zone has a contact zone, a supply line zone, and a connection zone; the supply line zone electrically connects the contact zone to the connection zone, and the connection zone is electrically connectable to sensor electronics. The surface capacitance between the contact zone and the outside surface of the substrate is greater than the surface capacitance between the contact zone and the outside surface of the cover pane.

Claims

1. A composite pane with a capacitive switching zone, comprising: a substrate, at least one first intermediate layer, which is areally bonded to the substrate, at least one second intermediate layer, which is areally bonded to the first intermediate layer, and a cover pane, which is areally bonded to the second intermediate layer, wherein a carrier film with an electrically conductive layer is arranged, at least in sections, between the first intermediate layer and the second intermediate layer, at least one capacitive switching zone is electrically isolated from the electrically conductive layer by at least one coating-free separating line, the capacitive switching zone has a contact zone, a supply line zone, and a connection zone; the supply line zone electrically connects the contact zone to the connection zone, and the connection zone is electrically connectable to sensor electronics, and a surface capacitance c.sub.I between the contact zone and an outside surface of the substrate is greater than a surface capacitance c.sub.A between the contact zone and an outside surface of the cover pane.

2. The composite pane according to claim 1, wherein a ratio of the surface capacitance c.sub.I to the surface capacitance c.sub.A is greater than or equal to 1.1:1.

3. The composite pane according to claim 1, wherein the supply line zone has a length l.sub.Z of 1 cm to 70 cm and has a width b.sub.Z of 0.5 mm to 10 mm.

4. The composite pane according to claim 1, wherein a ratio of length l.sub.Z to width b.sub.Z of the supply line zone is less than or equal to 1:700.

5. The composite pane according to claim 1, wherein an area of the contact zone is from 1 cm.sup.2 to 200 cm.sup.2 and/or has the shape of a rectangle, square, trapezoid, triangle, circle, ellipse, or drop or has rounded corners.

6. The composite pane according to claim 1, wherein a region of the electrically conductive layer outside the capacitive switching zone forms a surrounding zone, which is connectable to the sensor electronics via another connection zone.

7. The composite pane according to claim 1, wherein a width t.sub.1 of the separating line is from 30 μm to 200 μm.

8. The composite pane according to claim 1, wherein the first intermediate layer and/or the second intermediate layer is transparent, contains or is made of polyvinyl butyral (PVB), and/or has a relative permittivity ∈.sub.r,2/3/3′ of 2 to 4.

9. The composite pane according to claim 1, wherein the carrier film is transparent, contains or is made of polyethylene terephthalate, and/or has a relative permittivity ∈.sub.r,5 of 2 to 4.

10. The composite pane according to claim 1, wherein the substrate and/or the cover pane contains glass or polymers, and/or has a relative permittivity ∈.sub.r,1/4 of 2 to 8.

11. The composite pane according to claim 1, wherein the electrically conductive layer is transparent and/or has a sheet resistance of 0.4 ohm/square to 200 ohm/square and/or contains silver (Ag), indium tin oxide (ITO), fluorine-doped tin oxide (SnO.sub.2:F), or aluminum-doped zinc oxide (ZnO:Al).

12. A pane arrangement comprising: a composite pane according to claim 1, and capacitive sensor electronics, which are electrically connected to the connection zone, wherein the sensitivity of the sensor electronics is selected such that a switching signal is issued when the contact zone on the surface of the substrate is touched by a human finger and no switching signal or a different switching signal is issued when the contact zone on the surface of the cover pane is touched.

13. A pane arrangement comprising: a composite pane according to claim 1, and capacitive sensor electronics, which are electrically connected to the connection zone, wherein the sensitivity of the sensor electronics is selected such that a switching signal is issued when the contact zone on the surface of the substrate and/or the surface of the cover pane is touched by a human finger and no switching signal or a different switching signal is issued when the supply line zone on the surface of the substrate and/or the surface of the cover pane is touched.

14. A method for producing a composite pane according to claim 1, comprising: (a) applying an electrically conductive layer on a surface of a carrier film, (b) introducing at least one separating line, which electrically divides the layer (6) into at least one capacitive switching zone and at least one surrounding zone, and (c) producing a stack sequence consisting of a substrate, a first intermediate layer, a second intermediate layer, and a cover pane, wherein the carrier film is arranged, at least in sections, between the first intermediate layer and the second intermediate layer, and (d) laminating the stack sequence to form a composite pane.

15. A method comprising utilizing the composite pane according to claim 1 in means of transportation for travel on land, in the air, or on water, and as a built-in component in furniture, devices, and buildings.

16. A method comprising utilizing the capacitive switching zone according to claim 1 for the electrical control of a function inside or outside the composite pane, a change in an optical transparency of a functional intermediate layer.

17. The composite pane according to claim 2, wherein the ratio of the surface capacitance c.sub.I to the surface capacitance c.sub.A is greater than or equal to 1.2:1.

18. The composite pane according to claim 3, wherein the supply line zone has a length l.sub.Z of 1 cm to 8 cm and has a width b.sub.Z of 0.5 mm to 2 mm.

19. The composite pane according to claim 3, wherein the supply line zone has a shape of a rectangle, a strip, or a line.

20. The composite pane according to claim 4, wherein the ratio of length l.sub.Z to width b.sub.Z of the supply line zone is from 1:5 to 1:100.

21. The composite pane according to claim 5, wherein the area of the contact zone is from 1 cm.sup.2 to 9 cm.sup.2.

22. The composite pane according to claim 7, wherein the width t.sub.1 of the separating line is from 70 μm to 140 μm.

23. The composite pane according to claim 8, wherein the relative permittivity ∈.sub.r,2/3/3′ is from 2.1 to 2.9.

24. The composite pane according to claim 9, wherein the relative permittivity ∈.sub.r,5 is from 2.7 to 3.3.

25. The composite pane according to claim 10, wherein the glass is selected from the group consisting of flat glass, float glass, quartz glass, borosilicate glass, soda lime glass, and the polymers are selected from the group consisting of polyethylene, polypropylene, polycarbonate, polymethyl methacrylate, and/or mixtures thereof.

26. The composite pane according to claim 10, wherein the relative permittivity ∈.sub.r,1/4 is from 6 to 8.

27. The composite pane according to claim 11, wherein the sheet resistance is from 0.5 ohm/square to 20 ohm/square.

28. The method for producing a composite pane according to claim 14, wherein the at least one separating line is introduced by laser patterning or by mechanical or chemical ablation.

29. The method according to claim 15, wherein the composite pane is a windshield, rear window, a side window, and/or roof panel as well as a functional individual piece of a motor vehicle.

30. The method according to claim 15, comprising using the composite pane as an electric heater.

31. The method according to claim 16, wherein the function is a heating function or a lighting, and the functional intermediate layer is a suspended particle device (SPD) layer or an electrochromic intermediate layer.

Description

[0075] In the following, the invention is explained in detail with reference to drawings and exemplary embodiments. The drawings are a schematic representation and not true to scale. The drawings in no way restrict the invention.

[0076] They depict:

[0077] FIG. 1A a plan view of an embodiment of a pane arrangement according to the invention with a composite pane according to the invention,

[0078] FIG. 1B a cross-sectional representation along the section line A-A′ of FIG. 1A,

[0079] FIG. 1C an enlarged representation of the carrier film according to the invention of FIG. 1A,

[0080] FIG. 1D a cross-sectional representation along the section line B-B′ of FIG. 1C,

[0081] FIG. 2A a plan view of an alternative embodiment of the pane arrangement according to the invention with a composite pane according to the invention,

[0082] FIG. 2B a cross-sectional representation along the section line A-A′ of FIG. 2A,

[0083] FIG. 2C an enlarged representation of the carrier film according to the invention of FIG. 2A,

[0084] FIG. 2D a cross-sectional representation along the section line B-B′ of FIG. 2C, and

[0085] FIG. 3 a detailed flow chart of one embodiment of the method according to the invention.

[0086] FIG. 1A depicts a plan view of an exemplary embodiment of a pane arrangement 101 according to the invention with a composite pane 100 according to the invention.

[0087] FIG. 1B is a cross-sectional representation along the section line A-A′ of FIG. 1A. The composite pane 100 comprises here, for example, one substrate 1 and one cover pane 4 that are bonded to each other via a first intermediate layer 2 and a second intermediate layer 3. The composite pane 100 is, for example, a motor vehicle pane and, in particular, the windshield of a passenger car. The dimensions of the composite pane 100 are, for example, 0.9 m×1.5 m. The substrate 1 is, for example, intended to be turned toward the interior in the installed position. In other words, the outside surface IV of the substrate 1 is accessible from the interior; whereas, in contrast, the outside surface I of the cover pane 4 points outward relative to the vehicle interior. The substrate 1 and cover pane 4 are made, for example, of soda lime glass. The thickness d.sub.1 of the substrate 1 is, for example, 1.6 mm and the thickness d.sub.4 of the cover pane 4 is 2.1 mm. Of course, the substrate 1 and cover pane 4 can have any thicknesses, and, for example, can also be implemented with the same thickness. The intermediate layers 2,3 are thermoplastic intermediate layers and are made of polyvinyl butyral (PVB). They have, in each case, a thickness d.sub.2/3 of 0.38 mm. A carrier film 5 with a capacitive switching zone 10 is arranged between the first intermediate layer 2 and the second intermediate layer 3 in the central, lower section of the composite pane 100.

[0088] FIG. 1C depicts an enlarged representation of the carrier film 5 according to the invention of FIG. 1A. FIG. 1D depicts a corresponding cross-sectional representation along the section line B-B′ of FIG. 1C.

[0089] The carrier film 5 is, in this example, a transparent polyethylene terephthalate (PET) film with a thickness d.sub.5 of 0.05 mm. A transparent, electrically conductive layer 6 is arranged on the carrier film 5. The electrically conductive layer 6 is a layer system that includes, for example, three electrically conductive silver layers that are separated from one another by dielectric layers.

[0090] The electrically conductive layer 6 extends, for example, over one entire side of the carrier film 5. In the exemplary embodiment depicted, the electrically conductive layer 6 is arranged on that side of the carrier film 5 that faces the substrate 1. The carrier film 5 is set back by a distance of roughly 8 mm from the pane edge into the pane interior. This region is hermetically sealed by gluing the two intermediate layers 2,3 during lamination such that the electrically conductive layer 6 is protected against moisture from the surroundings of the composite pane 100 and, thus, against corrosion and damage. Alternatively, it would be possible to leave the carrier film 5 coating free in an edge region or to remove the electrically conductive layer 6 there.

[0091] The electrically conductive layer 6 is divided by coating-free separating lines 7 into different zones electrically isolated from each other. In the example depicted in FIG. 1C, two capacitive switching zones 10 are electrically divided by a common surrounding zone 15. Each switching zone 10 includes a contact zone 11, which is implemented approx. square and transitions into a strip-shaped supply line zone 12. The width b.sub.B and the length l.sub.B of the contact zone 11 is, in each case, for example, 40 mm. The width b.sub.Z of the supply line zone 12 is, for example, 1 mm. The ratio of b.sub.Z:b.sub.B is thus roughly 1:40. The supply line zone 12 is connected to a connection zone 13. The connection zone 13 has a square shape and an edge length b.sub.A of, for example, 12 mm. The length l.sub.Z of the supply line zone is roughly 48 mm.

[0092] The separating line 7 has only a width t.sub.1 of, for example, 100 μm and is introduced into the electrically conductive layer 6, for example, by laser patterning. Separating lines 7 with such a low width are hardly perceptible optically and interfere only a little with vision through the composite pane 100, which, particularly for use in motor vehicles, is of special importance for driving safety and is also particularly aesthetic.

[0093] The connection zone 13 is electrically conductively connected to a foil conductor 17 via an electrical line connection 20. A reliable electrically conductive connection is preferably obtained by means of an electrically conductive adhesive. The foil conductor 17 is made, for example, from a 50-μm-thick copper foil and is, for example, insulated outside the connection zone 13 with a polyimide layer. Thus, the foil conductor 17 can be guided out, without an electrical short, beyond the surrounding zone 15 over the bottom edge of the composite pane 100. Of course, the electrical line connection of the connection zone to the outside can also be guided outward via insulated wires or via a zone in which the electrically conductive layer of the surrounding zone is interrupted.

[0094] Here, the foil conductor 17 is, for example, connected to capacitive sensor electronics 14 outside the composite pane 100. Moreover, the surrounding zone 15 is also connected to the sensor electronics 14 via another connection zone 16. The sensor electronics 14 are suited to precisely measure capacitance changes of the switching zone 10 relative to the surrounding zone 15 and to forward a switching signal, for example, to the CAN-Bus of a motor vehicle as a function of a threshold value. Any functions in the motor vehicle can be switched via the switching signal. For example, lighting in or on the composite pane 100 can be switched on or off.

[0095] When the composite pane 100 is used, for example, as a windshield in a motor vehicle, the length of the supply line zone 12 can be selected such that the driver of the vehicle or the front seat passenger can comfortably reach the contact zone 11 of the switching zone 10.

[0096] In the exemplary embodiment depicted, the structure and tuning of the sensor electronics 14 are coordinated such that when the outside pane surface IV of the substrate 1 is touched above the contact zone 11 of the capacitive switching zone 10, a switching signal is triggered, whereas when the outside pane surface I of the cover pane 4 is touched over the capacitive switching zone 10, no switching signal is triggered. To this end, the thicknesses and the materials of the composite pane according to the invention 100 are selected according to the invention such that the surface capacitance c.sub.I between the contact zone 11 and the outside surface IV of the substrate 1 is greater than the surface capacitance c.sub.A between the contact zone 11 and the outside surface I of the cover pane 4.

[0097] The surface capacitance c.sub.I or c.sub.A is, in the context of the present invention, defined as the capacitance of a plate capacitor of that zone of the composite pane 100 that results from orthogonal projection of the contact zone 11 between the contact zone 11 and the outside surface IV of the substrate 1 or the outside surface I of the cover pane 4, with the resultant capacitance normalized to the area of the contact zone.

[0098] In the example depicted in detail in FIG. 1B, the surface capacitance c.sub.I between the contact zone 11 and the outside surface IV of the substrate 2 results as the serial connection of the individual capacitances (1/c.sub.1+1/c.sub.2).sup.−1, with the individual capacitance resulting at c.sub.i=∈.sub.0*∈.sub.r,i/d.sub.i. This corresponds to the capacitance C.sub.i of the respective individual layer with relative permittivity ∈.sub.r,i and thickness d.sub.i, normalized to the area A of the contact zone 11, i.e., c.sub.i=C.sub.i/A.

[0099] Moreover, the surface capacitance c.sub.1 between the contact zone 11 and the outside surface I of the cover pane 4 results as the serial connection of the individual capacitances (1/c.sub.3+1/c.sub.4+1/c.sub.5).sup.−1.

[0100] The relative permittivity of the substrate 1 and of the cover pane 4 are, here, for example, ∈.sub.r,1=∈.sub.r,4=7; the relative permittivity of the first intermediate layer 2 and the second intermediate layer 3 are, here, for example, ∈.sub.r,2=∈.sub.r,3=2.6; and the relative permittivity of the carrier film 5 is, here, for example, ∈.sub.r,5=3.

[0101] This yields a ratio of the surface capacitances c.sub.I:c.sub.A at 1.2:1.

[0102] Moreover, in this example, the area A of the contact zone 11 and in particular its width b.sub.B is coordinated with the width b.sub.Z of the supply line zone 12 such that a switching signal is issued only when the outside surface IV of the substrate is touched above the contact zone 11 (i.e., in the region of the surface IV that results from orthogonal projection of the contact zone 11 onto the surface IV) and not when the surface IV above the supply line zone 12 is touched.

[0103] FIG. 2A depicts a plan view of an alternative exemplary embodiment of a pane arrangement 101 according to the invention with the composite pane 100 according to the invention.

[0104] FIG. 2B is a cross-sectional representation along the section line A-A′ of FIG. 2A. The composite pane 100 comprises here, for example, one substrate 1 and one cover pane 4, which are bonded to each other via a first intermediate layer 2 and a second intermediate layer 3. The composite pane 100 is, for example, a motor vehicle pane and, in particular, the roof panel of a passenger car. The dimensions of the composite pane 100 are, for example, 1.2 m×1.2 m. The substrate 1 is, for example, intended to be turned toward the interior in the installed position. In other words, the outside surface IV of the substrate 1 is accessible from the interior; whereas, in contrast, the outside surface I of the cover pane 4 points outward. The substrate 1 and cover pane 4 are made, for example, of soda lime glass. The thickness d.sub.1 of the substrate 1 is, for example, 2.1 mm; and the thickness d.sub.4 of the cover pane 4 is, for example, also 2.1 mm. In this exemplary embodiment, the second intermediate layer 3,3′ is implemented in two layers. The intermediate layers 2,3,3′ are thermoplastic intermediate layers and are made of polyvinyl butyral (PVB). They have, in each case, a thickness d.sub.2/3/3′ of 0.38 mm. A carrier film 5 with a capacitive switching zone 10 is arranged between the first intermediate layer 2 and the second intermediate layer 3 in the central, lower section of the composite pane 100.

[0105] FIG. 2C depicts an enlarged representation of the carrier film 5 according to the invention of FIG. 2A. FIG. 2D depicts a corresponding cross-sectional representation along the section line B-B′ of FIG. 2C.

[0106] The carrier film 5 is, in this example, a transparent polyethylene terephthalate (PET) film with a thickness d.sub.5 of 0.05 mm. Here, the carrier film 5 has a length of, for example, 250 mm and a width of, for example, 120 mm. A transparent, electrically conductive layer 6 is arranged on the carrier film 5. The electrically conductive layer 6 is a layer system that includes, for example, three electrically conductive silver layers that are separated from one another by dielectric layers.

[0107] The electrically conductive layer 6 extends, for example, over the entire surface of one side of the carrier film 5, minus a 10-mm-wide coating-free edge strip 18 that is turned toward the outer pane edge of the composite pane 100. This region is hermetically sealed by gluing the two intermediate layers 2,3 during lamination such that the electrically conductive layer 6 is protected against moisture from the surroundings of the composite pane 100 and, thus, against corrosion and damage. In the exemplary embodiment depicted, the electrically conductive layer 6 is arranged on the side of the carrier film 5 that is turned toward the substrate 1.

[0108] The electrically conductive layer 6 is divided by coating-free separating lines 7 into different zones electrically isolated from each other. In the example depicted in FIG. 2C, four capacitive switching zones 10 are electrically divided by a common surrounding zone 15. Each switching zone 10 includes a contact zone 11, which is implemented approx. drop-shaped and transitions into a strip-shaped supply line zone 12. The width b.sub.B and the length I.sub.B of the contact zone 11 is, in each case, for example, 40 mm. The width b.sub.Z of the supply line zone 12 is, for example, 1 mm. The ratio of b.sub.Z:b.sub.B is thus roughly 1:40. The supply line zone 12 is connected to a connection zone 13. The connection zone 13 has a square shape with rounded corners and an edge length b.sub.A of, for example, 12 mm. The length l.sub.Z of the supply line zone is roughly 48 mm.

[0109] The separating line 7 has only a width t.sub.1 of, for example, 100 μm and is introduced into the electrically conductive layer 6, for example, by laser patterning. Separating lines 7 with such a low width are hardly perceptible optically and interfere only a little with vision through the composite pane 100, which, particularly for use in motor vehicles as a roof panel, is particularly aesthetic.

[0110] The connection zone 13 is electrically conductively connected to a foil conductor 17 via an electrical line connection 20. A reliable electrically conductive connection is preferably obtained by means of an electrically conductive adhesive. The foil conductor 17 is made, for example, from a 50-μm-thick copper foil and is, for example, insulated outside the connection zone 13 with a polyimide layer. Thus, the foil conductor 17 can be guided out, without an electrical short, beyond the surrounding zone 15 over the bottom edge of the composite pane 100. Of course, the electrical connection of the connection zone 13 to the outside can also be guided outward via insulated wires or via a zone in which the surrounding zone 15 is interrupted.

[0111] Here, the foil conductor 17 is, for example, connected to capacitive sensor electronics 14 outside the composite pane 100. Moreover, the surrounding zone 15 is also connected to the sensor electronics 14 via another connection zone 16. The sensor electronics 14 are suited to precisely measure capacitance changes of the switching zone 10 relative to the surrounding zone and to forward a switching signal, for example, to the CAN-Bus of a motor vehicle as a function of a threshold value. Any functions in the motor vehicle can be switched via the switching signal. For example, the composite pane 100 can have a suspended particle device (SPD) layer, an electrochromic or other type of layer or film for controlling the optical transparency, which can be altered in its optical transparency by means of the switching signal, here, for example, with four transparency levels, which can, in each case, be selected via the four capacitive switching zones. Of course, alternatively or additionally, other electrical functions such as electrical heating or electrical lighting can also be controlled.

[0112] When the composite pane 100 is used, for example, as a roof panel in a motor vehicle, the length of the supply line zone 12 can be selected such that the driver of the vehicle, the front seat passenger, or passengers in the back seat can comfortably reach the contact zone 11 of the switching zone 10. Of course, for this, multiple carrier films 5 can also be arranged in the composite pane 100, for example, in each case, a carrier film 5 for each vehicle occupant.

[0113] In the exemplary embodiment depicted, the structure and tuning of the sensor electronics 14 are coordinated such that when the outside pane surface IV of the substrate 1 is touched above the contact zone 11 of the capacitive switching zone 10, a switching signal is triggered, whereas when the outside pane surface I of the cover pane 4 is touched, no switching signal is triggered. This has the particular advantage that no switching signal can be triggered as a result of intentional or inadvertent touching of the composite pane 100 from outside the motor vehicle. In addition, the inadvertent triggering of a switching signal, for example, by rain or a carwash, is avoided. To this end, the thicknesses and the materials of the composite pane 100 according to the invention are selected according to the invention such that the surface capacitance c.sub.I between the contact zone 11 and the outside surface IV of the substrate 1 is greater than the surface capacitance c.sub.A between the contact zone 11 and the outside surface I of the cover pane 4.

[0114] In the example depicted in detail in FIG. 2B, the surface capacitance c.sub.I between the contact zone 11 and the outside surface IV of the substrate 2 results as the serial connection of the individual capacitances (1/c.sub.1+1/c.sub.2).sup.−1. Moreover, the surface capacitance c.sub.I between the contact zone 11 and the outside surface I of the cover pane 4 results as the serial connection of the individual capacitances (1/c.sub.3+1/c.sub.3′1/c.sub.4+1/c.sub.5).sup.−1. The relative permittivity of the substrate 1 and of the cover pane 4 here are, for example, ∈.sub.r,1=∈.sub.r,4=7; the relative permittivity of the first intermediate layer 2 and the second intermediate layer 3,3′ here are, for example, ∈.sub.r,2=∈.sub.r,3=∈.sub.r,3′=2,6; and the relative permittivity of the carrier film 5 here is, for example, ∈.sub.r,5=3. This yields a ratio of the surface capacitances c.sub.I:c.sub.A at 1.4:1.

[0115] Moreover, in this example, the area A of the contact zone 11 and in particular its width b.sub.B is coordinated with the width b.sub.Z of the supply line zone 12 such that a switching signal is issued only when the outside surface IV of the substrate is touched above the contact zone 11 (i.e., in the region of the outside surface IV that results from orthogonal projection of the contact zone 11 onto the outside surface IV) and not when the outside surface IV is touched above the supply line zone 12.

[0116] FIG. 3 depicts a flowchart of an exemplary embodiment of the method according to the invention for producing a composite pane 100 with a capacitive switching zone 10.

[0117] Table 1 depicts the calculation of the ratios of the surface capacitances c.sub.I:c.sub.A of five exemplary embodiments Example 1-5 for various material thicknesses and material parameters. The calculation of the surface capacitances was presented in detail above under FIG. 1 and FIG. 2. Example 3 corresponds to the exemplary embodiment of FIG. 1 and Example 1 corresponds to the exemplary embodiment of FIG. 2.

TABLE-US-00001 TABLE 1 Example 1 Example 2 Example 3 Example 4 Example 5 Thickness Thickness Thickness Thickness Thickness [mm] [mm] [mm] [mm] [mm] Cover pane (4) 2.1 2.1 2.1 2.1 1.8 Glass, ε.sub.r = 7 Second 0.76 0.76 0.38 0.38 0.38 intermediate layer (3) PVB, ε.sub.r = 2.6 Carrier film (5) 0.05 0.05 0.05 0.05 0.05 PET, ε.sub.r = 3 First 0.38 0.38 0.38 0.38 0.38 intermediate layer (2) PVB, ε.sub.r = 2.6 Substrate (1) 2.1 1.6 1.6 1.8 1.4 Glass, ε.sub.r = 7 c.sub.A in F/m.sup.2 1.45E−08 1.45E−08 1.91E−08 1.91E−08 2.11E−08 c.sub.I in F/m.sup.2 1.98E−08 2.36E−08 2.36E−08 2.20E−08 2.56E−08 c.sub.I:c.sub.A 1.4 1.6 1.2 1.1 1.2

[0118] Composite panes 100 according to the invention have ratios of surface capacitances c.sub.I:c.sub.A greater than or equal to 1.1:1. With such ratios, it was possible to obtain a particularly good differentiation between touching the contact surface 11 above the outside surface IV of the substrate 1 in contrast with the outside surface I of the cover pane 4.

[0119] The composite pane 100 according to the invention according to FIGS. 1 and 2 has a capacitive switching zone 10, which is, for example, connectable to capacitive sensor electronics 14. Moreover, due to the low width of the separating lines 7, vision through the pane is only minimally affected and meets, for example, the requirements for motor vehicle glazing.

[0120] Particularly advantageously and surprisingly, a pane arrangement 101 with a composite pane 100, wherein the sensitivity of the sensor electronics 14 with the ratio of the surface capacitances c.sub.I:c.sub.A above the contact zones 11 is tuned such that selective triggering of the switching operation is possible only from an outside surface IV of the composite pane 100.

[0121] This result was unexpected and surprising for the person skilled in the art.

LIST OF REFERENCE CHARACTERS

[0122] 1 substrate [0123] 2 first intermediate layer [0124] 3,3′ second intermediate layer [0125] 4 cover pane [0126] 5 carrier film [0127] 6 electrically conductive layer [0128] 7 separating line [0129] 10 capacitive switching zone [0130] 11 contact zone [0131] 12 supply line zone [0132] 13 connection zone [0133] 14 capacitive sensor electronics [0134] 15 surrounding zone [0135] 16 additional connection zone [0136] 17 foil conductor [0137] 18 coating-free edge strip [0138] 20 electrical line connection [0139] 100 composite pane [0140] 101 pane arrangement [0141] A area of the contact zone 11 [0142] b.sub.A width of the connection zone 13 [0143] b.sub.B width of the contact zone 11 [0144] b.sub.Z width of the supply line zone 12 [0145] C.sub.I, C.sub.A, C.sub.1 . . . 5 surface capacitance [0146] C.sub.1 . . . 5 capacitance [0147] d.sub.1,d.sub.2,d.sub.3,d.sub.3′,d.sub.4,d.sub.5 thickness [0148] ∈.sub.0 electric field constant [0149] ∈.sub.r,1, ∈.sub.r,2, ∈.sub.r,3, ∈.sub.r,3′, ∈.sub.r,4, ∈.sub.r,5 relative permittivity [0150] l.sub.A length of the connection zone 13 [0151] l.sub.B length of the contact zone 11 [0152] l.sub.Z length of the supply line zone 12 [0153] t.sub.1 width of the separating line 7 [0154] A-A′ section line [0155] B-B′ section line [0156] I outside surface of the cover pane 4 [0157] IV outside surface of the substrate 1