Heated Coated Glazing

Abstract

The invention relates to glazing having a conductive coating having one or more data transmission windows for transmitting data to/from electronic devices in a vehicle, in which a deletion line surrounds the data transmission window. The deletion line defines first and second regions of the conductive coating. The first region comprises an electrically heated region and first and second busbars for supplying electrical power. The second region comprises at least one data transmission window. The second region may be electrically isolated from the second busbar so that the second region cannot be electrically heated.

Claims

1) A glazing, comprising: a conductive coating suitable for electrical heating; a deletion line defining first and second regions of the conductive coating wherein the first region comprises: an electrically heated region; and first and second busbars for supplying electrical power to the electrically heated region the second region comprising at least one data transmission window.

2) A glazing according to claim 1, wherein the second region is electrically isolated from the second busbar.

3) A glazing according to claim 1, comprising a second data transmission window.

4) A glazing according to claim 1, wherein the deletion line width is 100 um or less.

5) A glazing according to claim 1, wherein the deletion line width is 10 um or less.

6) A glazing according to claim 1, wherein the deletion line is a laser ablation line.

7) A glazing according to claim 1, wherein each data transmission window is at least 40 mm wide and at least 20 mm in height.

8) A glazing according to claim 1, wherein the first busbar extends substantially parallel with and adjacent to a portion of an upper edge of the glazing.

9) A glazing according to claim 1, further comprising an auxiliary busbar separated from the first busbar by the deletion line.

10) A glazing according to claim 1, wherein the first busbar and the deletion line are arranged to contact each other, so that a corner of the electrically heated region is formed.

11) A glazing according to claim 1, wherein the conductive coating has sheet resistance in the range 2 ohms per square to 20 ohms per square.

12) A glazing according to claim 1, further comprising a carrier film for carrying the conductive coating.

13) A glazing according to claim 1, further comprising first and second sheets of interlayer material, wherein the carrier film is laid over the first sheet of interlayer material and wherein the second sheet of interlayer material is laid over the carrier film.

14) An automotive vehicle having a glazing according to claim 1, wherein the interior of the vehicle is provided with at least one transmitter or receiver arranged to transmit or receive an electromagnetic data signal through at least one of the data transmission windows.

15) A process for manufacture of a glazing comprising: providing a conductive coating suitable for electrical heating; ablating a deletion line by a laser, so as to define first and second regions of the conductive coating; providing in the first region an electrically heated region by laying down first and second busbars for supplying electrical power to the electrically heated region; and providing in the second region at least one data transmission window.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The invention will now be described by means of non-limiting examples with reference to the attached figures.

[0030] FIG. 1 shows a glazing according to the invention comprising one data transmission window.

[0031] FIG. 2 shows a glazing according to the invention comprising two data transmission windows.

DETAILED DESCRIPTION OF THE INVENTION

[0032] Although the invention is described herein with particular reference to an automotive windscreen, it will be understood that it has applications to other vehicle glazing, for example a rear window or a side window.

[0033] FIG. 1 shows a glazing 1, according to the invention, comprising a conductive coating 10 extending over a substantial portion of the glazing.

[0034] A deletion line 20 is provided to define first and second regions 10a, 10b of the conductive coating 10. The deletion line 20 is typically narrow, so as to be invisible for a driver when the glazing 1 is installed in a vehicle. For a typical windscreen installation, a deletion line width should be 100 um or narrower.

[0035] First and second busbars 11, 12 are provided in the first region 10a for supplying electrical power to an electrically heated region 10c of the conductive coating 10. Typically the first busbar 11 is adjacent to an upper edge of the glazing 10 and the second busbar 12 is adjacent to a lower edge of the glazing 1.

[0036] A data transmission window 30 is provided in the second region 10b of the conductive coating 10 at a position suitable for one or more transmitters or receivers. Typically a data transmission window 30 is adjacent an upper edge of the glazing 1.

[0037] The data transmission window 30 is in a portion of the glazing 1 in which the conductive coating 10 is at least partly absent. The conductive coating may be removed by any deletion method, such as laser ablation or scratching.

[0038] The conductive coating 10 may be on a carrier film, such as a thin sheet of polyethylene terephthalate (PET). The carrier film is typically laid over a first sheet of interlayer material, such as polyvinylbutyral (PVB). First and second busbars 11, 12 are arranged in contact with the electrically heated region 10c of the conductive coating 10. The carrier film and the first sheet of interlayer material are arranged on a first sheet of glass. A second sheet of interlayer material is laid over the carrier film, so that the carrier film is arranged between the first and second sheets of interlayer material. A second sheet of glass is laid over the first and second busbars 11, 12.

[0039] FIG. 2 shows an embodiment of the invention, in which a glazing 1 comprises a conductive coating 10 and first and second busbars 11, 12. Two data transmission windows 30, 31 are provided in a second region 10b of the conductive coating 10. The second region 10b is separated from the first region 10a by a deletion line 20. Second region 10b is unheated, because it is electrically isolated from the second busbar 12. Second region 10b may be in contact with first busbar 11.

[0040] In the embodiment of FIG. 2, a length of the first busbar 11 is limited, so as to provide electrical power to only a portion of the electrically heated region 10c, bounded by the deletion line 20. An auxiliary busbar 13 is provided, separated from the first busbar 11 by the deletion line 20, for supplying electrical power to another portion of the electrically heated region 10c. Typically the auxiliary busbar 13 and the first busbar 11 are electrically connected by a wire external to the glazing.

[0041] First and second data transmission windows 30, 31 may be of any shape and size, for example circular, trapezoidal, rectangular with rounded corners or U-shaped.

[0042] The deletion line 20 may define the second region 10b to have any shape.

[0043] The deletion line 20 may circumscribe the second region 10b.

[0044] The second region 10b may extend between the deletion line 20 and an edge of the conductive coating 10.

EXAMPLES OF THE INVENTION

[0045] A glazing was prepared according to the invention, in which a deletion line defined a second region of a conductive coating, and comprising a data transmission window in the second region. A comparative example was prepared having similar features but without a deletion line between the data transmission window and an electrically heated region.

[0046] In both the example and the comparative example, a conductive coating 10 was provided on a carrier film comprising a sheet of PET. Surface resistivity of the conductive coating 10 on the carrier film was between 2 and 20 ohms per square. The sheet of PET was laid over a first sheet of interlayer material (PVB) in a manner known in the art.

[0047] A first busbar 11 and an auxiliary busbar 13 were arranged on an electrically heated region 10c of the conductive coating 10 on the sheet of PET. The first sheet of PVB and the sheet of PET were laid over the first sheet of glass.

[0048] The sheet of PET was cut back from an edge of the first sheet of glass, in a manner known in the art to avoid corrosion at the edge of a laminated glazing. The cut-back edge of the sheet of PET and a ceramic print, known as an obscuration band, printed on surface 2 (inner surface) of the first sheet of glass, were arranged so that the cut-back edge was hidden by the obscuration band.

[0049] A second sheet of interlayer material (PVB) was laid over the carrier film so that the carrier film was between the two sheets of PVB. A second sheet of glass was laid on top of the second sheet of PVB to form an assembly. The assembly was pressed at its edges and degassed, then subjected to elevated temperature and elevated pressure in an autoclave according to a process known in the art to form a laminated glazing 1.

[0050] An electrical power supply was connected to the laminated glazing 1 by means of external wires, serving as electrodes. A positive electrode was connected to the first busbar 11, in parallel with the auxiliary busbar 13, and a negative electrode was connected to the second busbar 12. The laminated glazing 1 was thus electrically heated for a predetermined period. At the end of the predetermined period a temperature distribution was measured. The predetermined period was 12 minutes and a measurement apparatus was a thermal imaging camera.

[0051] In the comparative example, hotspots were observed exceeding 95 degrees C., which is defined as a threshold of unacceptable temperature. By contrast, in the example according to the invention no unacceptable hotspots were observed.