Flat electric heater element, in particular for glass panes of a motor vehicle

1. A flat electric heater element, comprising:

a carrier film;

two current conductor layers arranged on a first face of the carrier film at a distance from each other;

an electrical resistance layer arranged on the first face, extending between the two current conductor layers and being in electrically conductive contact with the two current conductor layers, wherein an electric current is flowable through the electrical resistance layer between the current conductor layers;

an adhesive layer including electrically insulating material and disposed over the electrical resistance layer and the current conductor layers, wherein the adhesive layer has a self-adhesive surface for adhesively bonding the flat electric heater element to an element to be heated, and the element to be heated includes thermally conductive material; and

at least one passage opening, the carrier film, the current conductor layers and the electrical resistance layer extending around the passage opening,

wherein

the carrier film has at least one relatively wide region and at least one relatively narrow region adjacent to the at least one relatively wide region along an edge of the passage opening,

the at least one relatively wide region of the carrier film carries more electrical resistance material of the electrical resistance layer than the at least one relatively narrow region for generating more heating energy than the at least one relatively wide region, and

the carrier film, the two current conductor layers, and the electrical resistance layer are all present in the at least one relatively wide region and in the at least relatively narrow region along the edge of the passage opening.

2. The flat electric heater element according to claim 1 , wherein the electrical resistance layer includes a material having a positive temperature coefficient, and a resistance of the material is configured to increase as a temperature rises and decrease as the temperature falls.

3. The flat electric heater element according to claim 1 , wherein at least one of the two current conductor layers, the adhesive layer, and the electrical resistance layer is screen printed.

4. The flat electric heater element according to claim 1 , wherein at least one of the two current conductor layers is a continuous ring line extending around an entirety of the at least one passage opening.

5. The flat electric heater element according to claim 1 , further comprising electric connection elements on a second face of the carrier film facing away from the first face, wherein the connection elements are electrically conductively connected to the current conductor layers.

6. The flat electric heater element according to claim 1 , further comprising a protective pull-off layer on the self-adhesive surface of the adhesive layer.

7. A motor vehicle, comprising:

a flat electric heater element;

a glass pane; and

a signaling device,

wherein

the flat heater element is adhesively bonded to inside of the glass pane for heating a region of the glass pane,

the flat heater element includes:

a carrier film;

two current conductor layers arranged on a first face of the carrier film at a distance from each other;

an electrical resistance layer arranged on the first face, extending between the two current conductor layers and being in electrically conductive contact with the two current conductor layers, wherein an electric current is flowable through the electrical resistance layer between the current conductor layers;

an adhesive layer including electrically insulating material and disposed over the electrical resistance layer and the current conductor layers, wherein the adhesive layer has a self-adhesive surface for adhesively bonding the flat heater element to the glass pane; and

at least one passage opening, the carrier film, the two current conductor layers and the electrical resistance layer extending around the passage opening,

wherein

the carrier film has at least one relatively wide region and at least one relatively narrow region adjacent to the at least one relatively wide region along an edge of the passage opening,

the at least one relatively wide region of the carrier film carries more electrical resistance material of the electrical resistance layer than the at least one relatively narrow region for generating more heating energy than the at least one relatively wide region,

the carrier film, the two current conductor layers, and the electrical resistance layer are all present in the at least one relatively wide region and the at least relatively narrow region along the edge of the passage opening,

said region of the glass pane is opposite the passage opening of the flat heater element,

the signaling device is configured to receive or transmit signals through the passage opening and the region of the glass pane, and

the signaling device is at least one of a receiver, a transmitter or a transceiver.

8. The flat electric heater element according to claim 1 , wherein the carrier film, the two current conductor layers, the adhesive layer, and the electrical resistance layer define a closed loop surrounding the passage opening.

9. The flat electric heater element according to claim 8 , wherein each of the current conductor layers comprises projections alternatingly arranged along the closed loop.

10. The flat electric heater element according to claim 9 , wherein each of the projections protrudes from one of the current conductor layers toward the other current conduct layer and is in contact with the electrical resistance layer.

11. The flat electric heater element according to claim 1 , wherein the electrical resistance layer at least partially overlaps the two current conductor layers, and the two current conductor layers are positioned between the carrier film and the electrical resistance layer.

12. The flat electric heater element according to claim 1 , wherein the electrical resistance layer at least partially overlaps the two current conductor layers, and the electrical resistance layer is positioned between the carrier film and the two current conductor layers.

13. The flat electric heater element according to claim 1 , wherein the electrical resistance layer is between the two current conductor layers without overlapping the two current conductor layers.

14. The flat electric heater element according to claim 1 , wherein

a distance between opposite side edges of the at least one relatively wide region is larger than a distance between opposite side edges of the at least one relatively narrow region, and

a distance between the two current conductor layers in the at least one relatively wide region is larger than that in the at least one relatively narrow region.

15. The flat electric heater element according to claim 14 , wherein

the carrier film, the electrical resistance layer and the two current conductor layers have elongated shape, and

each of the carrier film, the electrical resistance layer and the two current conductor layers continuously extends around the at least one passage opening to define a closed loop.

16. The motor vehicle according to claim 7 , wherein

a distance between opposite side edges of the at least one relatively wide region is larger than a distance between opposite side edges of the at least one relatively narrow region, and

a distance between the two current conductor layers in the at least one relatively wide region is larger than that in the at least one relatively narrow region.

17. The motor vehicle according to claim 16 , wherein

the carrier film, the electrical resistance layer and the two current conductor layers have elongated shape, and

each of the carrier film, the electrical resistance layer and the two current conductor layers continuously extends around the at least one passage opening to define a closed loop.

18. The flat electric heater element according to claim 14 , wherein a distance between opposite side edges of the electrical resistance layer in the at least one relatively wide region is larger than in the at least one relatively narrow region.

19. The motor vehicle according to claim 16 , wherein a distance between opposite side edges of the electrical resistance layer in the at least one relatively wide region is larger than in the at least one relatively narrow region.