An electrically heated window for a vehicle includes a smooth surfaced transparent sheet having a plurality of spaced electric resistance heating conductors on the surface thereof. A humidity detector is provided on the inside surface of the sheet and includes two sets of conductors standing in relief above the surface of the sheet and each having substantially the shape of a comb with the teeth of the two combs interdigitated and extending substantially in the direction of maximum slope of the sheet. The back of the upper comb defines a gutter for the diversion of water droplets from the area occupied by the teeth of the combs.

This invention refers to a diversity antenna system for use in a motor vehicle with at least two diversity antennas as well as a window-mounted heater structure consisting of lateral conductors (bus bars) supplying the heater current and heater sections in between. The configuration is such that each diversity antenna has lateral bus bars (4a, 4d; 4b, 4c) and heater sections (2a, 2b) between them as well as a pair of terminals connected to a feeder network (8a, 8b) of the diversity antenna. Each pair of terminals has a ground connection point (14a, 14b) and a tap point on a bus bar (5a, 5b). The tap points on the bus bars (5a, 5b) of the diversity antennas are located such that they are essentially isolated from each other with respect to radio frequencies. The power leads to the bus bars are provided with RF traps (6a through 6d). This serves to optimize the mean signal quality yielded by each individual antenna and to minimize the coincidence of interference in the signals coming from the antennas.

An anti-fogging glass having a plurality of conductive heating lines, a pair of bus bars to which both ends of the respective heating lines are connected, and terminal portions on the respective bus bars, to which terminals for supplying a current are to be connected, wherein the plurality of heating lines comprise first heating lines and second heating lines in a predetermined proportion to the plurality of heating lines, the second heating lines are connected in the vicinity of at least one terminal portion, and the vicinity of the terminal portion, in which the second heating lines are connected, is a second region other than a first region constituting a current pathway to the first heating line.

A vehicle window heating system for eliminating moisture deposited on the surface of a vehicle window is provided with a moisture detecting circuit having a temperature sensitive element adapted to compensate for temperature-dependent variation in impedance between a pair of dew-drop detecting electrodes. The deposit of dew drops between the aforesaid electrodes lowers impedance therebetween, whereupon moisture eliminating heating means operates due to such lowered impedance. A decrease in ambient temperature increases impedance, and the aforesaid moisture eliminating heating means will not operate unless a more pronounced dew depositing condition results. This device, however, compensates for such a temperature-dependent variation in impedance and thus may operate substantially in a temperature independent dew-depositing condition.

A humidity-responsive heating circuit for a window of an automotive vehicle includes a grid of heating conductors on the window and two conductors closely approaching each other on the surface of the window such that the resistance between them changes, upon the appearance of humidity bridging the space between them, sufficiently to provide a signal. All of the conductors are composed of the same paste having the same properties and are applied as a single baked, silk screen printed pattern. The circuit may further include a switch to apply a voltage between those two conductors, amplifying means responsive to change of resistance between them, and a relay controlled by the amplifying means for connection of the heating grid to a source of voltage.