Heated vehicle window
A heated vehicle window includes at least one ply of a glazing material, provided with an antenna and an array of electrical conductors forming a heating circuit. The heating circuit comprises a plurality of electrical conductors and at least two busbars for supplying direct electrical current to which the electrical conductors are connected. A discrete electrically conductive layer is provided to cover at least a portion of at least two of the busbars in direct current electrical isolation therefrom. The busbars and the discrete electrically conductive layer act as a capacitor in the presence of alternating electrical current.
1. A heated vehicle window comprising at least one ply of a glazing material, provided with an antenna and comprising an array of electrical conductors forming a heating circuit, the heating circuit comprising a plurality of electrical conductors and at least two busbars for supplying direct electrical current to which the electrical conductors are connected, wherein a discrete electrically conductive layer is provided to cover at least a portion of at least two of the busbars in direct current electrical isolation therefrom, such that the busbars and the discrete electrically conductive layer act as a capacitor in the presence of alternating electrical current.
2. The heated vehicle window of claim 1 , wherein the discrete electrically conductive layer is bonded to the busbars by an electrically insulating adhesive layer.
3. The heated vehicle window of claim 1 , wherein n busbars are provided, where n is an integer number, and greater than or equal to two, and the number discrete electrically conductive layers is in the range of 1 to n−1.
4. The heated vehicle window of claim 3 , wherein n is at least three and wherein a direct electrical connection is made between one of the busbars and the discrete electrically conductive layer covering that busbar.
5. A heated vehicle window comprising at least one ply of a glazing material, provided with an antenna and comprising an array of electrical conductors forming a heating circuit, the heating circuit comprising a plurality of electrical conductors and at least two busbars for supplying direct electrical current to which the electrical conductors are connected, wherein a discrete electrically conductive layer is provided to cover at least a portion of at least two of the busbars, such that the busbars and the discrete electrically conductive layer act as a capacitor in the presence of alternating electrical current, and wherein there is a direct electrical connection between one of the at least two busbars and the discrete electrically conductive layer covering that busbar.
6. The heated vehicle window of claim 5 , wherein n busbars are provided, where n is an integer number, and greater than or equal to two, and the number discrete electrically conductive layers is in the range of 1 to n−1.
7. The heated window of claim 4 , wherein the direct electrical connection is used to connect the heating circuit to a direct current source.
8. The heated vehicle window of claim 1 , wherein the electrically conductive layer is formed from a metallic thin sheet material.
9. The heated vehicle window of claim 1 , wherein the electrically conductive layer is a layer of a fired electrically conductive ink, preferably a silver containing ink.
10. The heated vehicle window of claim 9 , wherein the electrically conductive layer is isolated from the busbar by means of an electrically insulating fired ink.
11. The heated vehicle window of claim 1 , wherein the electrically conductive layer is provided with an outer protective layer, preferably a self-adhesive polymer film or a printed black ceramic material.
12. The heated vehicle window of claim 1 , wherein the electrical conductors are heating lines printed with an electrically conductive silver-containing ink.
13. The heated vehicle window of claim 1 , comprising a single ply of a glazing material.
14. The heated vehicle window of claim 1 , comprising two plies of a glazing material bonded together by a layer of an interlayer material.
15. The heated vehicle window of claim 14 , wherein the electrical conductors are formed from metal wires.
16. The heated vehicle window of claim 1 , wherein the glazing material is silicate float glass.
17. The heated window of claim 16 , wherein a layer of a printed black ceramic material is provided between the silicate float glass and the electrical conductors.
18. The heated vehicle window of claim 1 , wherein the glazing material is a plastics material.
19. The heated vehicle window of claim 1 , wherein the discrete electrically conductive layer acts as an antenna connector.
20. The heated vehicle window of claim 1 , wherein the discrete electrically conductive layer is adapted to produce another antenna having a resonant frequency of at least 100 MHz.
21. The heated vehicle window of claim 20 , wherein the other antenna comprises a second electrically conductive layer, in direct current electrical isolation from the discrete electrically conductive layer.
22. The heated vehicle window of claim 21 , wherein the second electrically conductive layer is adjacent the discrete electrically conductive layer.
23. The heated vehicle window of claim 21 , wherein the second electrically conductive layer overlaps the discrete electrically conductive layer.
24. The heated vehicle window of claim 20 , wherein the other antenna is formed from a portion of the discrete electrically conductive layer.