Electrically heated window

Claim 1

A window comprising a transparent sheet of glass having a pair of bus bars disposed adjacent to a pair of opposite end edges of said glass sheet, each bus bar extending from one end portion thereof near one side of said glass sheet through a center portion thereof to another end portion thereof near the opposite side of said glass sheet, said bus bars tapering in width from their central portions to their end portions, and spaced electroconductive members interconnected between said bus bars, said bus bars and said spaced electroconductive members being rigidly attached to a surface of said glass sheet to form a heating circuit for said window, with certain of said electroconductive members interconnecting the respective central portions of said bus bars, other of said electroconductive members interconnecting one end portion of one of said pair of bus bars toward one side of said window to a corresponding end portion of the other of said pair of bus bars toward said one side and still other electroconductive members interconnecting the other end portion of said one of said pair of bus bars toward the other side of said window to the corresponding other end portion of the other of said pair of bus bars toward said other side, said bus bars and said electroconductive members being of approximately uniform thickness throughout their length, the electroconductivity per unit length of said bus bars in said central portions being at least 20 times that of each of said electroconductive members and the electroconductivity per unit length of said end portions of said bus bars being more than 1 time but less than 10 times that of each of said electrocoNductive members, and means disposed in approximately the longitudinal center of each of said bus bar central portions adapted to connect said bus bars to a source of power.