Bus bar arrangement for uniformly heating a trapezoidally-shaped electrically heated windshield

In an electrically heated windshield construction in which said windshield (a) is of generally trapezoidal shape, (b) has both an upper generally horizonally extending bus bar of uniform conductivity throughout its length and a lower generally horizonally extending bus bar of uniform conductivity throughout its length, and (c) a continuous and uniformly thick trapezoidal-shaped electrically conductive coating on said windshield which electrically interconnects said upper bus bar and said lower bus bar;

• an improved bus bar configuration in which:
• said bus bars are formed in a manner such that (1) the line of contact of said upper generally horizonally extending bus bar with said electrically conductive coating has a length which extends generally along an entire effective length of an upper edge of said electrically conductive coating on said windshield, and (2) the line of contact of said lower generally horizontally extending bus bar being symetrically located on the lower edge of said electrically conductive coating and having a length equal to the sum of said length of said line of contact of said upper bus bar plus generally about one-half of the difference between the entire effective length of the lower edge of said electrically conductive coating on said windshield minus said length of said line of contact of said upper bus bar.