Chip Module Contact Coating for Thin Gold Corrosion Protection
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Solution Overview
Problem
The use of thin gold plating layers (less than 0.02 μm) on chip card modules compromises both corrosion resistance and the golden appearance, making them unsuitable for bank and identity verification applications due to reduced protective effects and visible nickel layers.
Innovation Solution
A chip module with a contact surface featuring a dual-layer protective coating composed of an organic silicon compound and silicon oxide, which maintains corrosion resistance and golden appearance even with thin gold layers, achieving an electrical surface contact resistance of not more than 500 mΩ.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If thin gold plating layers are used to reduce cost, then material cost decreases, but corrosion resistance deteriorates
Solution Approach 1:
The protective function is segmented into two independent layers: a thin gold layer for cost savings and appearance, and a separate organic coating layer for corrosion protection. This allows each layer to perform its specialized function without requiring the gold layer to be thick enough to provide both appearance and corrosion resistance alone.
Solution Approach 2:
The patent creates a composite structure combining metal (gold) and organic coating materials. The gold layer provides electrical conductivity, appearance, and basic corrosion resistance, while the organic coating layer enhances corrosion protection. Together they form a composite system that achieves both cost reduction and maintained reliability.
2Quantity of substance
If thin gold plating layers are used to reduce cost, then material cost decreases, but appearance quality deteriorates
Solution Approach 1:
The patent segments the functional requirements by allowing the thin gold layer to specialize in providing appearance and electrical properties, while the organic coating layer specializes in corrosion protection. This segmentation enables the gold layer to be thin enough to reduce cost while still maintaining its appearance function.
3Quantity of substance
If thin gold plating layers are used, then material cost decreases, but electrical surface contact resistance increases
Solution Approach 1:
The patent changes the parameters of the organic coating to ensure it has sufficient electrical conductivity. By selecting appropriate organic coating materials and optimizing their thickness and composition, the coating maintains electrical surface contact resistance within acceptable limits (not more than 500 mΩ) while still providing corrosion protection.
4Reliability
If thicker gold plating layers are used to maintain appearance and corrosion resistance, then quality is maintained, but material cost increases
Solution Approach 1:
The patent applies segmentation by dividing the protective function between a thin gold layer and an organic coating layer. This allows the gold layer to be thin (reducing cost) while the organic coating provides the necessary corrosion protection, eliminating the need for thick gold layers.
Solution Approach 2:
The patent replaces expensive long-lasting gold protection with a combination of thin expensive gold and cheaper organic coating. The organic coating acts as a sacrificial or complementary protective layer that extends the life and effectiveness of the thin gold layer, reducing overall material cost while maintaining performance.
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
The dual-layer coating enables the use of thin gold layers while preserving corrosion resistance and the golden appearance, meeting the requirements of ISO/IEC 7810 and ISO/IEC 10373-1 standards, enhancing market acceptance.
Implementation Method 1
a coating of the contact surface with a double layer composed of a lower layer of an organic silicon compound and/or a carbon compound and an upper layer of silicon oxide
Implementation Method 2
coating of the contact surface with a double layer composed of a lower layer of an organic silicon compound and/or a carbon compound and an upper layer of silicon oxide
Data Source
AI summary
A chip module having a contact surface for contact-based communication with a reader, where the contact surface includes a metal, and a coating of the contact surface with a double layer composed of a lower layer of an organic silicon compound and/or a carbon compound and an upper layer of silicon oxide, wherein the double layer has a thickness that has an electrical surface contact resistance of not more than 500 mO according to ISO 7810 when measured in accordance with ISO 10373-1.