COMPOSITE PANE COMPRISING AN ELECTRICALLY HEATABLE CAMERA WINDOW

Abstract

A composite pane with an electrically heatable camera window, which includes, inside the camera window, a first electrically conductive transparent coating for heating the camera window, wherein the first electrically conductive transparent coating is arranged on the first surface of the inner pane inside the camera window and has two busbars provided for connection to a voltage source, which are arranged on two opposite sides of the camera window such that when an electrical voltage is applied to the busbars, a current flows through the first electrically conductive transparent coating.

Claims

1. A composite pane with an electrically heatable camera window, comprising: an outer pane and an inner pane, which are joined to one another flat via at least one thermoplastic intermediate layer, wherein the outer pane comprises a surface facing away from the intermediate layer and a second surface facing the intermediate layer, and the inner pane comprises a first surface facing the intermediate layer and a second surface facing away from the intermediate layer, at least one optically transparent camera window, inside the camera window, a first electrically conductive transparent coating for heating the camera window, wherein the first electrically conductive transparent coating is arranged on the first surface of the inner pane inside the camera window and has two busbars provided for connection to a voltage source, which are arranged on two opposite sides of the camera window such that when an electrical voltage is applied to the two busbars, a current flows through the first electrically conductive transparent coating.

2. The composite pane according to claim 1, wherein at least one of two busbars has a width of 0.1 mm to 30 mm.

3. The composite pane according to claim 1, wherein the two busbars are formed from a printed and baked printing paste.

4. The composite pane according to claim 1, wherein the two busbars are implemented as two strips.

5. The composite pane according to claim 1, wherein a layer thickness of the two busbars is 5 m to 40 m.

6. The composite pane according to claim 1, wherein the first electrically conductive transparent coating is arranged over an entire surface on the first surface of the inner pane inside the camera window.

7. The composite pane according to claim 1, wherein the composite pane has a second electrically conductive transparent coating on the first surface of the inner pane.

8. The composite pane according to claim 7, wherein the first electrically conductive transparent coating and the second electrically conductive transparent coating are the same.

9. The composite pane according to claim 7, wherein the first electrically conductive transparent coating and/or the second electrically conductive transparent coating have infrared-reflecting properties.

10. The composite pane according to claim 7, wherein a coating-free separation line is provided for electrical insulation of the first electrically conductive transparent coating from the second electrically conductive transparent coating, wherein the coating-free separation line at least partially surrounds the camera window.

11. The composite pane according to claim 10, wherein the coating-free separation line has a width of 30 m to 200 m.

12. The composite pane according to claim 1, wherein the camera window has at least one coating-free communication window for the transmission of electromagnetic radiation through the composite pane, wherein the communication window has an area of 10% to 30% of an area of the camera window.

13. The composite pane according to claim 1, wherein the composite pane is a windshield.

14. A method for producing a composite pane according to claim 1, comprising: applying the first electrically conductive transparent coating to at least part of the first surface of the inner pane, applying the two busbars to the first electrically conductive transparent coating on two opposite sides of the camera window, wherein the two busbars are arranged such that when an electrical voltage is applied to the two busbars, a current flows through the first electrically conductive transparent coating, and joining the first surface of the inner pane with the electrically conductive transparent coating to the second surface of the outer pane via the thermoplastic intermediate layer.

15. A method comprising providing a composite pane according to claim 1 in a locomotion vehicle for traffic on land, in the air, or on water.

16. The composite pane according to claim 2, wherein the width is from 4 mm to 20 mm.

17. The composite pane according to claim 3, wherein the printed and baked printing paste contains metal particles and/or carbon.

18. The composite pane according to claim 4, wherein the two busbars are implemented as two parallel strips.

19. The composite pane according to claim 5, wherein the layer thickness of the two busbars is 8 m to 20 m.

20. The method according to claim 15, wherein the composite pane is a windshield.

Description

[0052] The invention is explained in greater detail in the following with reference to figures and exemplary embodiments. The figures are a schematic representation and are not to scale. The figures in no way restrict the invention.

[0053] They depict:

[0054] FIG. 1 a plan view of an embodiment of the composite pane according to the invention with an electrically heatable camera window,

[0055] FIG. 2 an enlarged representation of the camera window of FIG. 1,

[0056] FIG. 3 a cross-sectional representation along the section line A-A of FIG. 2,

[0057] FIG. 4 a cross-sectional representation of the camera window along the section line B-B of FIG. 2, and

[0058] FIG. 5 a flow chart of an embodiment of the method according to the invention.

[0059] Specifications with numerical values are generally not to be understood as exact values, but also include a tolerance of +/1% up to +/10%.

[0060] FIG. 1 depicts a plan view of a preferred embodiment of the composite pane 10 according to the invention with a heatable camera window 2. The composite pane 10 can serve as a windshield of a passenger car. For this purpose, the camera window 2 is arranged centrally at the upper edge region of the composite pane 10 as a windshield. The camera window 2 serves as through-vision for a camera 5 (FIG. 3) or a camera system. The camera window 2 is defined as a region of the optical beam path of the camera 5 or of the camera system through the composite pane 10, in particular an inner pane 1 (of FIG. 3). A first electrically conductive transparent coating 6.1 is applied completely within the camera window 2. The first electrically conductive transparent coating 6.1 is hardly perceptible for the camera 5 and hardly interferes with through-vision through the composite pane 10.

[0061] In the installed position, the lower edge of the composite pane 10 is arranged downward toward the engine of a passenger car; its upper edge (O) positioned opposite the lower edge (U) is directed upward toward the roof. The camera window 2 is arranged roughly centrally in the vicinity of the upper edge (O).

[0062] FIG. 2 depicts an enlarged representation of the camera window 2 of FIG. 1. Two busbars 7.1 and 7.2, which are arranged on two opposite sides of the camera window such that when an electrical voltage is applied to the busbars, a current flows through the first electrically conductive transparent coating 6.1, are provided for the electrical contacting of the first electrically conductive transparent coating 6.1.

[0063] A first busbar 7.1 is arranged on the left edge region of the camera window 2 on the first electrically conductive coating 6.1. A second busbar 7.2 is arranged on the right edge region of the camera window 2 on the first electrically conductiven coating 6.1. The busbars 7.1 and 7.2 contain silver particles. They were applied on the first electrically conductive coating 6.1 by screen printing and then baked. The length of the busbars 7.1 and 7.2 corresponds approx. to the edge length of the camera window 2. When an electrical voltage is applied to the busbars 7.1 and 7.2, a uniform electrical heating current (indicated by arrows) flows through the first electrically conductive transparent coating 6.1. The camera window 2 is heated by the heating current. Each busbar 7.1, 7.2 is electrically conductively connected to a respective foil conductor 8.1, 8.2, which connects the busbars 7.1, 7.2 to an electrical voltage source 9.

[0064] A first foil conductor 8.1 is electrically conductively connected to the first busbar 7.1 via a soldering compound, an electrically conductive adhesive, or by simple placement and application of pressure within the composite pane 10. Similarly, a second foil conductor 8.2 is electrically conductively connected to the second busbar 7.2. The foil conductors 8.1 and 8.2 contain, for example, a tinned copper foil with a width of 10 mm and a thickness of 0.3 mm. The foil conductors 8.1 and 8.2 can also transition into connection cables that are connected to the voltage source 9. The voltage source 9 provides, for example, an on-board voltage customary for motor vehicles, preferably from 12 V to 15 V, and, for example, about 14 V. Alternatively, the voltage source 9 can also have higher voltages, for example, from 35 V to 45 V, and in particular 42 V.

[0065] In the example shown, the busbars 7.1, 7.2 have a constant thickness of, for example, about 0.1 mm and a constant specific resistance of, for example, 2.3 ohm-cm. When an electrical voltage is applied to the busbars 7.1, 7.2, an electrical current flows through the first coating 6.1. The busbars 7.1, 7.2 and their connections can be concealed by an opaque paint layer 11 (masking print).

[0066] FIG. 3 depicts a cross-section through the composite pane 10 according to the invention of FIG. 1 along the section line A-A. The composite pane 10 comprises an inner pane 1 that is joined to an outer pane 4 via an intermediate layer 3. The intermediate layer 3 can comprise a film made of a thermoplastic polymer, preferably EVA, PU, PVB, or mixtures or copolymers or derivatives thereof. The intermediate layer 3 has a substantially constant thickness of 0.76 mm. Alternatively, or additionally, the intermediate layer 3 can comprise two films made of a thermoplastic polymer, preferably EVA, PU, or mixtures or copolymers or derivatives thereof. In an installed state, the inner pane 1 faces an interior, e.g., a vehicle interior.

[0067] The inner pane 1 and the outer pane 4 are made, for example, of soda lime glass. The outer pane 4 has, for example, a thickness of 2.1 mm; the inner panel, a thickness of 1.6 mm or 2.1 mm.

[0068] The first electrically conductive transparent coating 6.1 is arranged on the first surface (III) of the inner pane 1 facing the first intermediate layer 3. The first coating 6.1 can be electrically contacted via the two busbars 7.1, 7.2. The paint layer 11 frames the camera window 2 of the composite pane 10.

[0069] A second electrically conductive transparent coating 6.2 is arranged outside the camera window 2, likewise on the first surface (III) of the inner pane 1 facing the intermediate layer 3. In this exemplary embodiment, the first coating 6.1 is electrically isolated from the second coating 6.2 by a coating-free separation line 12. The separation line 12 has, for example, a width of 70 m. The camera window 2 is formed by the separation line 12, since the separation line 12 completely surrounds the first electrically conductive coating 6.1. No electrical connection to a voltage source is provided on the second electrically conductive transparent coating 6.2. Consequently, also, no busbars are arranged on the second electrically conductive transparent coating 6.2.

[0070] The camera window 2 can be any region of the composite pane 10 or even of the inner pane 1 that has high transmission for the corresponding optical and electromagnetic signals. The camera window 2 is intended to provide an optical passage for the viewing area of the camera 5. In addition, a coating-free communication window inside the camera window 2 for transmission of electromagnetic radiation for other sensors attached to the composite pane 10 can be provided, whereby the communication window can have an area of 10% to 30% of the area of the camera window 2.

[0071] The camera window 2 is implemented transparent, in particular optically transparent. The camera 5 directed at the camera window 2 is situated in an encapsulation attached to the inner panel.

[0072] The first coating 6.1 and the second coating 6.2 are arranged on a surface (III) of the inner pane 1 facing the intermediate layer 3. In this embodiment, the first coating 6.1 and the second coating 6.2 are identical. The first and second electrically conductive coating 6.1, 6.2 are also sun-shading coatings with preferably at least one electrically conductive layer based on a metal, in particular based on silver. Such a sun-shading coating has, in particular, reflecting properties in the near infrared range, for example, in the range from 800 nm to 1500 nm.

[0073] FIG. 4 depicts a cross-section of the heatable camera window 2. The first surface (III) of the inner pane 1 and a second surface (II) of the outer pane 4 face one another and are joined to one another via the thermoplastic intermediate layer 3. A second surface (IV) of the inner pane 1 and a first surface (I) of the outer pane 4 face away from one another and from the thermoplastic intermediate layer 3. The first electrically conductive transparent coating 6.1 is arranged on the surface (III) of the inner pane 1. The first busbar 7.1 is arranged on the left edge region of the camera window 2 on the first electrically conductive coating 6.1. The second busbar 7.2 is arranged on the right edge region of the camera window 2 on the first electrically conductive coating 6.1.

[0074] It has been found that the heating action of the first coating is enhanced by the arrangement on side (III) in a way that could not be foreseen based on previously known heating devices.

[0075] FIG. 5 depicts a flow chart of an exemplary embodiment of the method according to the invention for producing the composite pane 10 with a heatable camera window 2. The method comprises the following steps: [0076] the first electrically conductive transparent coating 6.1 is applied to at least part the first surface (III) of the inner pane 1 (101), [0077] the two busbars 7.1, 7.2 are applied to the first electrically conductive transparent coating 6.1 on two opposite sides of the camera window 2, wherein the busbars 7.1, 7.2 are arranged such that when an electrical voltage is applied to the busbars 7.1, 7.2, a current flows through the first coating 6.1 (102), [0078] the first surface (III) of the inner pane (1) with the electrically conductive transparent coating (6.1) is joined to the surface (II) of the outer pane (4) via the thermoplastic intermediate layer (3).

LIST OF REFERENCE CHARACTERS

[0079] 1 inner pane [0080] 2 camera window [0081] 3 intermediate layer [0082] 4 outer pane [0083] 5 camera [0084] 6.1 first electrically conductive coating [0085] 6.2 second electrically conductive coating [0086] 7.1 first busbar [0087] 7.2 second busbar [0088] 8.1 first foil conductor [0089] 8.2 second foil conductor [0090] 9 voltage source [0091] 10 composite pane [0092] 11 paint layer [0093] 12 separation line [0094] (O) upper edge of the composite pane [0095] (U) lower edge of the composite pane [0096] (I) first surface of the outer pane facing away from the intermediate layer [0097] (II) second surface of the outer pane facing the intermediate layer [0098] (III) first surface of the inner pane facing the intermediate layer [0099] (Iv) second surface of the inner pane facing away from the intermediate layer