Ford Motor Company Limited

Kevin J Ramus

Patricia B Reid

John D Youngs

Robert F Tweadey

This specification is directed to a process for making part of an electrically heated windshield assembly. The process includes the steps of selecting a glass sheet 10. The glass sheet is formed into a windshield configuration. At least a pair of electrically conductive bus bars (14, 16) are formed on the glass sheet. One bus bar (14) extends along a lower edge of the glass sheet. A second of the bus bars (16) extends along at least a short portion (20) of the lower edge of the glass sheet in a location spaced away from the bus bar (14) and near the lower edge of the glass sheet, up a side edge of the lower edge of the glass sheet as an edge portion (22), and along an upper edge of the glass sheet as an upper portion (24). A snap-on protective member (30) is placed on the glass sheet which engages both front and back surfaces of that glass sheet. The snap-on protective member covers over lower portions and side edge portions of the second bus bar (16). The surface of the glass sheet having the bus bars thereon is subjected to a vacuum metal deposition process to form an electrically conductive coating (32) between the bus bars uncovered by the snap-on protective member. Thereafter, the snap-on protective member is removed to complete a part of the electrically heated windshield assembly.

Method for making a part of an electrically heated windshield assembly

This specification teaches an electrically heated, glass vision unit having a complex curved configuration. The unit is made by cutting a glass substrate (10) from a flat glass bracket (12). The glass substrate (10) has first and second surfaces separated by a uniform distance. A pair of electrically conductive bus bars (16--16) are applied to one of the surfaces of the glass substrate (10). The bus bars (16--16) are so positioned on the flat glass substrate (10) that when the substrate (10) is bent to form the glass vision unit of complex curved configuration, inboard edges (16a--16a) of the pair of electrically conductive bus bars (16--16) are equally distant from one another throughout their entire extent. The flat glass substrate (10) is bent to form the glass vision unit of complex curved configuration. A conductive coating (20) is applied to the one surface of the glass substrate (10) and extends between the pair of bus bars (16--16) throughout their entire extent. In this manner, when electrical energy is applied to the bus bars (16--16), a uniform flow of current takes place from one bus bar to another bus bar so that a uniformly developed heating pattern is established between the bus bars (16--16).

Electrically heated, glass vision unit

An improved electrically heated vision unit in which heat can be concentrated in a selected zone or zones thereof includes at least one sheet of a relatively rigid transparent material (12) having a ceramic enamel (14) extending along at least two opposite edges on one surface thereof. A bus bar is associated with each ceramic enamel on each edge of the sheet and has at least one narrow portion (18) overlying and bonded to an associated one of the ceramic enamel, and at least one wide portion (20) in part overlying and bonded to an associated one of said ceramic enamel and in part overlying and bonded to said one surface of the transparent material. The narrow portions and the wide portions of the pair of bus bars are in register with like portions on an opposed one of the bus bars. An electrically conductive transparent coating (22) of generally uniform thickness and composition extends between the pair of bus bars with sections thereof between juxtaposed wide portions of the pair of bus bars being bonded only to the wide portions of the bus bars and the one surface of the transparent material, and with other sections thereof between juxtaposed narrow portions of the pair of bus bars being bonded to the narrow portions of the bus bars, the ceramic enamel and the one surface of the transparent material. Structure is provided for supplying electrical energy to the bus bars and through the conductive coating.

Electrically heatable vision unit

This specification teaches a method of making an electrically heated, glass vision unit having a complex curved configuration. The method is initiated by cutting a glass substrate (10) from a flat glass bracket (12). The glass substrate (10) has first and second surfaces separated by a uniform distance. A pair of electrically conductive bus bars (16--16) are applied to one of the surfaces of the glass substrate (10). The bus bars (16--16) are so positioned on the flat glass substrate (10) that when the substrate (10) is bent to form the glass vision unit of complex curved configuration, the pair of electrically conductive bus bars (16--16) are equally distant from one another throughout their entire extent. The flat glass substrate (10) is bent to form the glass vision unit of complex curved configuration. A conductive coating (20) is applied to the one surface of the glass substrate (10) and extends between the pair of bus bars (16--16) throughout their entire extent. In this manner, when electrical energy is applied to the bus bars (16--16), a uniform flow of current takes place from one bus bar to another bus bar so that a uniformly developed heating pattern is established between the bus bars (16--16). The steps of bending the flat glass substrate and applying the conductive coating may be interchanged.

Method of making an electrically heated, glass vision unit

This specification teaches a method for making an electrically heatable windshield of laminated construction. In the method, a pair of glass templets are cut (10) and they include a long glass templet and a short glass templet. The templets are separated (20) from one another. An opaque ceramic paint is applied (30) to an edge portion of a coatable surface of a selected glass templet and is dried (40) thereon. Bus bars are also applied (50) to and dried (60) on the coatable surface of the long glass templet. The glass templets are united (70) and subjected to a bending operation (80) to form a shaped windshield pair. The long glass templet and short glass templet are separated (90). A transparent electrically conductive coating is applied (100) between the bus bars located on the selected glass templet. The templets are reunited (110) with an interposed laminating interlayer material and thereafter laminated (120) together to achieve a shaped laminated windshield which is heatable by the flow of electrical energy therethrough.

Method for making an electrically heatable windshield

An electrically heated windshield of generally trapezoidal shape has been bus bars of uniform conductivity throughout their length extending in line contact with the upper and lower edges of a continuous uniformly thick trapezoidal-shaped electrically conductive coating provided on the windshield surface for deicing and defrosting the windshield. The line of contact of the upper bus bar with the conductive coating has a length generally equal to the entire effective length of the upper edge of the conductive coating. The lower bus bar is symetrically located along the lower edge of the conductive coating and has a line of contact length equal to the sum of the length of the upper bus bar plus generally about one-half the difference between the entire effective length of the lower edge of the conductive coating minus the length of the line of contact of the upper bus bar.

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Dearborn, MI, United States of America

Kevin J Ramus