Method of attaching bus bars to a conductive coating for a heatable vehicle window

• US 6,625,875 B2
• Filed: 03/26/2001
• Issued: 09/30/2003
• Est. Priority Date: 03/26/2001
• Status: Expired due to Term

• Current Assignee: Guardian Europe S.A.R.L.. (Interguard Holding Corp.)
• Original Assignee: Centre Luxembourgeois de Recherches pour le Verre et la Ceramique SA
• Inventors: Sol, Jean-Marc
• Primary Examiner(s): Arbes, Carl J.
• Assistant Examiner(s): NGUYEN, TAI V
• Application Number:
  US09/816,757
• Publication Number:
  US 20030019859A1
• Time in Patent Office: 918 Days
• Field of Search: 296/11, 296/12, 296/13, 298/31, 298/46, 427/163.1, 427/374.1, 427/374.2, 427/374.3, 219/203, 219/543, 219/542
• US Class Current: 29/621
• CPC Class Codes: B32B 17/10036 comprising two outer glass sheets
• CPC Class Codes: B32B 17/10174 Coatings of a metallic or dielectric material on a constituent layer of glass or polymer
• CPC Class Codes: B32B 17/10229 Metallic layers sandwiched by dielectric layers
• CPC Class Codes: B32B 17/10761 containing vinyl acetal
• CPC Class Codes: H05B 2203/016 Heaters using particular connecting means
• CPC Class Codes: H05B 2203/017 Manufacturing methods or apparatus for heaters
• CPC Class Codes: H05B 3/84 Heating arrangements specially adapted for transparent or reflecting areas, e.g. for demisting or de-icing windows, mirrors or vehicle windshields
• CPC Class Codes: Y10T 29/49083 Heater type
• CPC Class Codes: Y10T 29/49085 Thermally variable
• CPC Class Codes: Y10T 29/49087 with envelope or housing
• CPC Class Codes: Y10T 29/49101 Applying terminal
• CPC Class Codes: Y10T 29/49128 Assembling formed circuit to base
• CPC Class Codes: Y10T 29/49155 Manufacturing circuit on or in base

Abstract

A heatable vehicle window (e.g., windshield, sidelite or backlite) includes a multi-layer coating formed on a substrate. The multi-layer coating includes at least one dielectric layer and at least one conductive layer. A pair of bus bars are deposited on the substrate over the coating, so that at least the dielectric layer is provided between the bus bars and the conductive layer(s). In order to create an electrical connection between the bus bars and the conductive layer(s) of the coating, the bus bars and/or coating is/are heated to a temperature sufficient to permit the bus bars to reach molten or semi-molten form. Portions of bus bar material then flow down through at least the dielectric layer of the coating (i.e., forming a contact hole in the coating) so as to contact the coating'"'"'s conductive layer(s). After cooling of the newly formed bus bars, the window may be selectively heated by passing current through the conductive layer(s) via the bus bars.

Claims

1. A method of making a heatable vehicle window, the method comprising:

depositing a multi-layer coating on a substrate, the multi-layer coating including at least one dielectric layer and at least one conductive layer;

forming first and second conductive bus bars on the substrate over the coating such that the bus bars as formed are not in electrical contact with the at least one conductive layer of the coating; and

heating at least the first and second bus bars to a temperature sufficient to cause at least portions of the respective bus bars to flow or migrate through the at least one dielectric layer creating respective contact holes therein and make contact with the at least one conductive layer, so that after cooling the first and second bus bars are in electrical contact with the at least one conductive layer of the coating.

2. The method of claim 1, wherein the bus bars have a lower transition or flowable point than a transition or flowable point of the at least one conductive layer.

3. The method of claim 1, further comprising:

following said heating and cooling, laminating the substrate with the bus bars and coating thereon to another substrate with a polymer layer therebetween to form a laminate, and

installing the laminate in a vehicle windshield frame to form a vehicle windshield assembly.

4. The method of claim 1, wherein said heating comprises heating at least the first and second bus bars to a temperature of from about 500-700 degrees C.

5. The method of claim 1, wherein the coating has a sheet resistance R_S less than or equal to 6 ohms/sq, the substrate is glass, and wherein during said heating the glass substrate is also heat bent into a desired vehicle windshield shape so that the flow or migration of the bus bars takes place during a heat bending step for the substrate.

6. The method of claim 1, wherein the coating includes the at least one conductive layer and another conductive layer, and wherein said heating comprises heating at least the first and second bus bars to a temperature sufficient to cause the bus bars to flow or migrate through multiple dielectric layers and one of the conductive layers creating contact hole(s) therein, and make contact with both the at least one conductive layer and the another conductive layer, so that after cooling the first and second bus bars are in electrical contact with the at least one conductive layer and the another conductive layer of the coating.

7. The method of claim 6, wherein the first and second bus bars comprise a silver frit material, and wherein the conductive layers comprise silver.

8. The method of claim 1, wherein the at least one dielectric layer comprises at least one of an oxide and a nitride.

9. The method of claim 1, wherein said multi-layer coating comprises at least firs and second conductive layers, and after said heating the first and second bus bars are each in electrical contact with each of said first and second conductive layers.

10. The method of claim 1, wherein said multi-layer coating comprises first and second layers comprising silver with at least one dielectric layer therebetween, and after said heating the first and second bus bars are each in electrical contact with each of the first and second layers comprising silver.

11. The method of claim 1, wherein said heating causes at least portions of the first and second bus bars to migrate through at least two different dielectric layers in order to make contact with the at least one conductive layer.

12. The method of claim 1, wherein said multi-layer coating comprises at least first and second dielectric layers located over an upper conductive layer, and at least a third dielectric layer located between the upper conductive layer and a lower conductive layer, and wherein said heating causes at least portions of the first and second bus bars to flow or migrate through at least the first, second and third dielectric layers so that after said heating the fist and second bus bars are in electrical contact with each of the upper and lower conductive layers.