GLASS SUBSTRATE PROVIDED WITH COPPER-BASED CONDUCTIVE STRIPS

Abstract

A glazing includes at least one glass sheet provided on one of the faces with an electrical network having resistance strips and collector strips, in which at least one portion of one face includes at least one strip obtained from an electrically conductive composition including a silver paste, the strip being in contact with another strip obtained from an electrically conductive composition including a copper paste, the other strip obtained from an electrically conductive composition including a copper paste being completely covered with a protective enamel layer.

Claims

1. A glazing comprising at least one glass sheet provided on a face thereof with an electrical network consisting of resistance strips and collector strips, wherein at least one portion of the face comprises at least one silver strip obtained from an electrically conductive composition comprising a silver paste, said silver strip being in contact with another copper strip obtained from an electrically conductive composition comprising a copper paste, said other copper strip obtained from an electrically conductive composition comprising a copper paste being completely covered with a protective enamel layer.

2. The glazing as claimed in claim 1, wherein the contact between the copper and silver strips is made at ends of the strip obtained from the electrically conductive composition comprising the copper paste.

3. The glazing as claimed in claim 1, wherein the copper strip partially covers the silver strip.

4. The glazing as claimed in claim 1, wherein the silver strip partially covers the copper strip.

5. The glazing as claimed in claim 1, wherein the copper strip and/or the silver strip is positioned on an enamel layer deposited on the glass sheet.

6. The glazing as claimed in claim 5, wherein the electrically conductive composition comprising the copper paste comprises between 70% and 90% by weight of copper powder and less than 15% by weight of glass frit.

7. The glazing as claimed in claim 1, wherein a thickness, measured after firing, of the copper strip comprising the copper paste is between 5 and 50 μm.

8. The glazing as claimed in claim 1, wherein the protective enamel layer covering the copper strip has a thickness, measured after firing, of between 5 and 40 μm.

9. The glazing as claimed in claim 1, wherein a portion of at least one face of the glass sheet comprises copper collector strips and/or copper resistance strips that are obtained from the electrically conductive composition based on copper paste and that are covered with the protective enamel layer.

10. The glazing as claimed in claim 9, wherein the copper resistance strips are directly deposited on the glass sheet and are covered with a pigment-free protective enamel layer.

11. A process for manufacturing a glazing as claimed in claim 1, comprising: depositing a layer of silver paste on a face of a glass sheet in order to form a strip, depositing a layer of copper paste in order to form another strip, the deposition steps being carried out so that there is at least one contact zone between the layer of silver paste and the layer of copper paste, then depositing a protective enamel layer over the whole of the layer of copper paste, and firing all of the layers deposited at a temperature of between 550° C. and 700° C., in air, for a duration of from 2 to 10 minutes.

12. The process as claimed in claim 11, wherein at least one of the deposition steps is carried out by screen printing.

13. The process as claimed in claim 11, wherein at least one of the deposition steps is carried out by digital printing.

14. The process as claimed in claim 11, further comprising a prior step of depositing an enamel layer on the face of the glass sheet on which the steps of depositing the layers of copper and/or silver paste will be carried out.

15. A device comprising a glazing as claimed in claim 1, said device being selected from the group consisting of a heated windshield, a rain sensor, an antenna, a radiant heater, an induction hob, a food warmer or a photovoltaic collector.

16. The glazing as claimed in claim 7, wherein the thickness, measured after firing, of the copper strip comprising the copper paste is between 5 and 30 μm.

17. The glazing as claimed in claim 8, wherein the protective enamel layer covering the copper strip has a thickness, measured after firing, of between 10 and 30 μm.

Description

[0035] The present invention also relates to heated windshields, rain sensors, antennae, radiant heaters, induction hobs, food warmers or photovoltaic collectors comprising a glazing as described above.

[0036] FIGS. 1 to 4 illustrate the invention and represent transverse cross sections of glazings according to the present invention.

[0037] In FIG. 1, the glass sheet (1) is covered with a silver strip (4) and with a copper strip (2). These two strips are directly deposited on the glass sheet. The silver strip is deposited first, and secondly the copper strip is deposited so as to partially cover the silver strip. The whole of the copper strip (2) is covered by a protective enamel layer (3). This layer (3) also extends over a portion of the silver strip (4) so as to create an enamel overlap zone (6) of the contact zone (7) between the silver strip and the copper strip. This configuration makes it possible to leave a portion of the silver strip not covered by the enamel layer (3). This is the zone (5) which forms the zone for welding the contact terminals. Usually, these terminals are welded to a single silver layer. Despite the stack of two screen-printed layers (copper strip and protective enamel), the welding zone remains similar to that which is found in customary electrical networks, i.e. that only comprise strips obtained from an electrically conductive composition based on silver paste.

[0038] In FIG. 2, the glass sheet (1) is also covered with a silver strip (4) and with a copper strip (2) and the copper strip (2) is the one that is deposited first.

[0039] The silver strip (4) is then deposited and partially covers the copper strip. The portion of the copper strip not covered by the silver strip is then protected by the protective enamel layer.

[0040] FIG. 3 represents the transverse cross section of a glazing on the face of which an enamel layer (8) is deposited. The copper strip (2) and silver strip (4) are deposited with the same configuration as that described in FIG. 1, directly on an enamel layer (8). The protective enamel layer (3) is deposited on the copper strip, which is thus completely encapsulated and not visible in the glazing. The welding zone (5) remains easily accessible and consists only of the silver strip (4).

[0041] FIG. 4 represents the transverse cross section of a glazing on the face of which an enamel layer (8) is deposited, the copper and silver strips being deposited according to the same configuration as that described in FIG. 2.

[0042] The enamel layer (8) is a layer that inevitably comprises at least one glass frit to enable a good adhesion to the glass.