HEATABLE GLAZING PANEL

Abstract

A laminated electrically heatable glazing panel includes: (i) a first outer and second inner substrates with respectively an internal and an external faces, laminated to one another via at least one polymer inclusive interlayer, (ii) a coating including at least one heatable conductive layer provided between the outer and the inner substrates, the coating divided into at least one heatable coating zone and at least one non-heatable coating zone, the first heatable zone being delimited by at least two zone boundaries which are insulating by a coating deletion area, and (iii) at least a first and second conductive bus bars, each of the spaced first and second bus bars adapted to supply electrical voltage across the at least one electrically heatable coating zone. Only the at least one electrically heatable coating zone is heated when current runs through said first and second bus bars and wherein the conductive path is defined between the busbars.

Claims

1. A laminated electrically heatable glazing panel comprising: a first outer and second inner substrates with respectively an internal and an external faces, laminated to one another via at least one polymer inclusive interlayer; a coating comprising at least one heatable conductive layer provided between the outer and the inner substrates, said coating divided into at least one heatable coating zone and at least one non-heatable coating zone, the first heatable zone being delimited by at least two zone boundaries which are insulating by a coating deletion area and at least a first and second conductive bus bars, each of said spaced first and second bus bars adapted to supply electrical voltage across the at least one electrically heatable coating zone, wherein only the at least one electrically heatable coating zone is heated when current runs through said first and second bus bars and wherein the conductive path is defined between the busbars.

2. The electrically heatable glazing panel according to claim 1, wherein at least one portion of the conductive path extends substantially from a lower edge of the glazing panel to an upper edge of the glazing panel.

3. The electrically heatable glazing panel according to claim 1, wherein the at least one electrically heatable zone is the main surface of the glazing.

4. The electrically heatable glazing panel according to claim 1, wherein the first and the seconds busbars are provided along the length of a lower edge and an upper edge of the glazing panel.

5. The electrically heatable glazing panel according to claim 1, wherein the electrically heatable zones are delimited by at least one zone boundary which is insulating by non-coated portions of the glazing panel.

6. The electrically heatable glazing panel according to claim 1, wherein the one of the first and second busbars extends along the first heatable coating zone.

7. The electrically heatable glazing panel according to claim 1, wherein the one or more zone boundaries have a width of 300 μm or more.

8. The electrically heatable glazing panel according to claim 1, wherein the coating layer is a solar control coating layer.

9. The electrically heatable glazing panel according to claim 1, wherein the coating layer has a resistance comprised between 2 and 25 ohms/square.

10. The electrically heatable glazing panel according to claim 1, wherein the substrate is a glass sheet.

11. The electrically heatable glazing panel according to claim 1, wherein first and second linear-shaped coating deletion areas delimit the at least one electrically heatable coating zone.

12. The electrically heatable glazing panel according to claim 1, wherein the glazing panel is automotive windshield.

13. The electrically heatable glazing panel according to claim 1, wherein the glazing panel is an automotive glazing formed in on piece of a windshield extended to a sunroof.

14. The electrically heatable glazing panel according to claim 1, wherein the glazing panel is a backlite wherein the decoating areas are perpendicular in planar view to upper and lower edges of the glazing panel.

15. The electrically heatable glazing panel according to claim 1, wherein the first heatable coating zone extends over the field of view of the passenger of an automotive.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0035] FIG. 1 is a top plan view of a heatable vehicle backlite according to another exemplary embodiment of this invention.

DETAILED DESCRIPTION

[0036] The invention will now be described, by way of example only, with reference to FIG. 1 which is schematic representations of a glazing panel.

[0037] Certain embodiments of this invention relate to a heatable vehicle window and more particularly a backlite including at least a first heating zone. A heatable coating (including one or more layers, at least one of which is conductive and heatable) is originally provided on a substrate of the window. The original coating is partially deleted so as to divide the original coating into at least two different spaced apart heatable coating portions and heating zone. First and second spaced apart conductive bus bars are provided over the heatable coating portions, with both bus bars being in electrical communication with each of the at least two different heatable coating portions. Using the two bus bars, current is caused to run through the at least one heating zone spaced apart heatable coating portions (but not connected to the busbars) in order to heat uniformly and efficiently the main zone corresponding to zone of visibility for an observer looking through such a glazing panel, thereby enabling the window to be heated.

[0038] Because of the division of the coating into at least two different coating portions, approximately uniform current distribution is enabled along the top bus bar so as to reduce the likelihood of overheating when the window is being heated.

[0039] Referring to FIG. 1, the vehicle backlite includes coating sandwiched between first and second glass substrates, respectively. Coating may be a single layer coating (e.g., of conductive Ag or ITO) in certain embodiments of this invention, or alternatively may be a multi-layer low-E coating in other embodiments of this invention Coating is at least partially deleted via deletion lines in order to divide the coating into at least two different spaced apart heatable coating portions, i.e., first heatable coating portion, second or/third intermediate coating portion not dedicated to be heated. Such deletion of the original coating may be done via laser deletion, sand-blasting deletion, a deleting abrasive wheel or disc, or any other suitable coating deletion technique/device.

[0040] Heatable coating portions are spaced apart from one another portions but not heated by insulating areas formed by the coating deletion (i.e., see deletion/insulating area between heatable coating portions and deletion/insulating area).

[0041] Because the coating is deleted via deletion lines, the first heatable zone is electrically insulated from one another coated portions (completely or at least partially). For purposes of example only, insulating/deletion areas can be formed in the shape of a fine line (e.g., providing a gap of about 0.5 mm or less). Optionally, in certain embodiments, the coating may also deleted along at least one edge of the window (e.g., see coating deletion area 4c along edge(s) of the window) so as to accommodate a bus bar lead, extension(s), or the like.

[0042] Still referring to FIG. 1, polyvinyl butyral (PVB) inclusive interlayer (not shown) is provided between the substrates, for conventional lamination purposes. According to certain embodiments of this invention, coating is provided on the interior surface of one of substrates so that the coating is provided on what is known conventionally as the backlite or windshield's second or third surface. FIG. 1 shows a glazing panel (10) in the form of a automotive backlite laminated glazing, a substantially transparent, electrically conductive coating layer (2) over substantially the entire surface of the glazing, bus bars (21, 22), and insulating zone boundaries (6), (7), which delimit one electrically heatable zones (31). The electrically heatable zone (31) is the zone of visibility for an observer looking through such a glazing panel. The two zone (42, 43) adjacent to the first heatable zone provided with an electrically coating are not heated since they are not electrically connected to the bubsbars (21, 22). Each bus bar is formed by example screen-printing a layer of silver paste of 40 □m thickness and 15 mm width.

[0043] Busbars are placed in the laminated glazing in contact with the heatable conductive coating.

[0044] In this embodiment, spaced bus bars 21, 22, disposed in the upper 35 and lower edge 36 of the glazing. In this embodiment, the busbars 21, 22 extended partially over the lateral edges of the glazing. The insulating zone boundaries, 7 which have preferably the form of lines delimit the zone 31 to be heated.

[0045] The busbar may be made in copper, then the busbar is stuck to the glazing thanks to an adhesive.

[0046] A conductive path of the first electrically heatable zone 31 is defined between the bus bars 21, 22 which are adapted to apply an electrical voltage across this electrically heatable zone.

[0047] The insulating zone boundaries 6, 7 are made by deletion of the coating. The deletion of the coating are made substantially perpendicularly to the upper and lower edges of the glazing 35, 36.

[0048] Advantageously, the coating layer may be removed with a laser, for example a laser DIODE. The zone boundaries may be substantially invisible to the naked eye, particularly if formed by laser removal of part of the coating layer. Advantageously, the width of the zone boundary is equal or higher than 300 μm. A zone boundary may delimit or substantially delimit one electrically heatable zone from another electrically heatable zone.

[0049] The bus bars may be hidden in use by concealment of the lower and lateral edges of the glazing panel in a vehicle body in which the glazing panel is adapted to be mounted.

[0050] According to another embodiment of the present invention, the glazing panel 10 may be an automotive canopy ie a windshield extending to the sun roof comprising a laminated glazing, a substantially transparent, electrically conductive coating layer over substantially the entire surface of the glazing, bus bars, and insulating zone boundaries, which delimit one electrically heatable zones. The electrically heatable zone is the zone of visibility for an observer looking through such a glazing panel. The two zone adjacent to the first heatable zone provided with an electrically coating are not heated since they are not electrically connected to the bubsbars. Each bus bar is formed by example screen-printing a layer of silver paste of 40 □m thickness and 15 mm width.

[0051] Busbars are placed in the laminated glazing in contact with the heatable conductive coating.

[0052] In this embodiment, spaced bus bars, are spaced laterally in the vicinity of the lateral edges of the glazing and in the lower edge of the glazing in contact with the heatable conductive coating. The busbar in this particular embodiment is made in one piece. The busbar may be made in copper, then the busbar is stuck to the glazing thanks to an adhesive. In this particular embodiment, the first boundary is provided in the lower part of the glazing and the second boundary is provided in the upper part of the glazing more particularly in “the winshields part” to delimit the to the zone of visibility for an observer looking through such a glazing panel. The canopy is in this case not heated by applying an electrical current. The busbar may be made in one piece.

[0053] The busbar may be made in copper, then the busbar is stuck to the glazing thanks to an adhesive.