Copper Conductive Strips with Protective Enamel for Vehicle Glazing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current glass substrate manufacturing processes using silver-based conductive strips are costly due to silver's high price and limited availability, and copper, while cheaper and conductive, lacks durability and corrosion resistance at high temperatures, making it unsuitable for long-term use in vehicle glazing without controlled atmosphere firing.
Innovation Solution
The use of copper-based conductive strips covered with a protective enamel layer, which includes glass frit and optional pigments, to prevent oxidation and corrosion, allowing for firing in air and maintaining electrical conductivity, with the copper and silver strips partially overlapping to ensure contact and protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If copper-based conductive strips are used to replace silver-based strips, then production cost is reduced, but corrosion resistance and durability at high temperatures deteriorate
Solution Approach 1:
The patent applies composite materials by combining copper conductive strips with a protective enamel coating. The enamel layer comprises glass frit, metal oxides (such as silicon dioxide, aluminum oxide, zinc oxide), and organic binders, creating a composite structure that provides both electrical conductivity from the copper and corrosion resistance from the enamel coating. This composite approach allows cost reduction through copper usage while maintaining reliability through the protective enamel layer.
Solution Approach 2:
The enamel coating acts as an intermediary protective layer between the copper conductive strip and the harsh environmental conditions (heat, moisture, chemicals). This intermediary layer prevents direct contact between the copper and corrosive elements, thereby maintaining the copper's electrical properties while protecting it from degradation. The enamel serves as a mediator that enables the use of cheaper copper material without sacrificing durability.
2Ease of manufacture
If copper-based conductive strips are used without controlled atmosphere firing, then manufacturing simplicity is improved, but oxidation and corrosion resistance deteriorate
Solution Approach 1:
The patent converts the harmful effect of oxidation into a beneficial protective mechanism. The enamel coating, which contains glass frit and metal oxides, forms a protective barrier that prevents oxidation of the copper strip during air firing. The oxidation-resistant properties of the enamel itself (rather than preventing oxidation entirely) protect the copper underlying layer, transforming the potential harm of oxidation into a beneficial protective function.
Solution Approach 2:
While not using a truly inert atmosphere, the enamel coating creates a protective environment around the copper strip that mimics inert conditions. The glass frit and metal oxide composition of the enamel forms a stable, non-oxidizing barrier that protects the copper from atmospheric oxidation during the firing process and subsequent service life, enabling air firing without controlled atmosphere equipment.
3Reliability
If silver-based conductive strips are used to ensure electrical conductivity and temperature resistance, then electrical performance is maintained, but material cost increases
Solution Approach 1:
The patent applies this principle by using copper, a cheaper material than silver, as the base conductive strip. While copper is less expensive and more abundant than silver, the patent extends its effective service life through the protective enamel coating that prevents corrosion and oxidation. This allows the use of cheaper copper material while maintaining reliability comparable to expensive silver-based strips.
Solution Approach 2:
The patent changes the material parameter from silver to copper, which has different cost and availability characteristics. By adjusting the composition parameters of the enamel coating (glass frit content, metal oxide ratios, organic binder types) to compensate for copper's lower inherent durability, the patent achieves comparable electrical performance and temperature resistance at reduced material cost.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution reduces silver usage, lowers production costs, and ensures copper strips withstand high temperatures and corrosion, maintaining electrical performance for the lifespan of vehicle glazing without requiring controlled atmosphere firing.
Implementation Method 1
at least one portion of one face comprises at least one strip obtained from an electrically conductive composition comprising a copper paste, said strip being in contact with another strip obtained from an electrically conductive composition comprising a silver paste, said other strip obtained from an electrically conductive composition comprising a copper paste being completely covered with a protective enamel layer
Implementation Method 2
the enamel is subsequently dried at 150° C. approximately and then fired in air at a temperature between 550° C. and 700° C. for a duration that varies from 2 to 10 minutes
Implementation Method 3
Copper is a cheap metal (cost of less than 10 per kilo) which has excellent conduction properties comparable to silver
Data Source
AI summary
A glazing includes at least one glass sheet provided on one of the faces with an electrical network having resistance strips and collector strips, in which at least one portion of one face includes at least one strip obtained from an electrically conductive composition including a silver paste, the strip being in contact with another strip obtained from an electrically conductive composition including a copper paste, the other strip obtained from an electrically conductive composition including a copper paste being completely covered with a protective enamel layer.