Abstract: A method of making an electrically heated window from at least two plies of transparent glazing material, at least one ply of interlayer material and an electrically resistant heating area device extending over one of the plies includes laying at least one length of busbar strip on one of the plies to form part of a busbar, positioning a separate corner piece of busbar strip adjacent the length of busbar strip to form a corner of the busbar, and electrically connecting the corner piece and the length of busbar strip to one another. An electrical connection device is arranged to extend from the electrically resistant area heating device past the peripheral edge of the window to terminate outside the window. The plies of glazing material are then laminated together with the ply of interlayer material and the electrically resistant area heating device extending between them.

Abstract: A window is provided which includes an array of fine, closely spaced wires through which electric current is passed to heat the window. Such windows are useful as vehicle windows, e.g. windscreens, because the heating disperses ice or condensation on the surface of the window, thereby improving visibility. According to the invention, at least some of the wires extend along diverging lines, so that the heated area extends over substantially the whole of the transparent portion of the window. It is also described how to achieve a sufficiently uniform heating effect over the extended heated area. A method of manufacturing such windows, and an apparatus for forming such arrays of wires, are also provided.

Abstract: A busbar supplies current to an electrically resistant area heating device, such as an array of fine closely-spaced wires, which extends over a window, e.g. a laminated vehicle windscreen. The busbar is arranged to turn a corner, e.g. a corner of the window, by providing a separate corner piece of busbar strip which is electrically connected to adjacent lengths of straight busbar strip. This facilitates concealment of the busbar, as is desirable for vehicle windscreens, especially when the corner piece is shaped to suit the corner of the window. Electrical connection of the corner piece to the adjacent lengths of busbar strip is achieved by use of a solder of low melting point, which melts on autoclaving of the window.