Dark Conductive Finish Layer for Electrical Contacts
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Solution Overview
Problem
Existing electrical contact coatings lack a combination of low contact resistance, dark appearance, and durability, particularly for applications in handheld devices where aesthetics and performance are crucial.
Innovation Solution
A finish layer comprising ruthenium oxide and/or iridium oxide, combined with metals like ruthenium, is applied using electrodeposition, offering a dark, electrically conductive, and durable coating with controlled composition and structure for improved conductivity and corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a dark coating material is used to achieve aesthetic appearance, then the L* value decreases (darker appearance), but the electrical conductivity deteriorates (contact resistance increases)
Solution Approach 1:
The patent applies composite materials by combining metal oxides (ruthenium oxide, iridium oxide) with conductive metals (silver, palladium, platinum) in the finish layer. This composite structure allows the metal oxide component to provide dark appearance (low L* value) while the conductive metal component maintains low contact resistance, resolving the contradiction between aesthetic darkness and electrical conductivity
Solution Approach 2:
The patent employs parameter changes by carefully controlling the composition ratios, atomic percentages, and thickness of the finish layer components. By adjusting these parameters, the coating achieves optimal balance between darkness (L* value ≤ 60) and conductivity (contact resistance < 1000 milliohms), transforming the trade-off into an optimized solution
2Reliability
If conventional coating materials are used to achieve low contact resistance, then electrical conductivity improves, but the appearance becomes less desirable (lighter color)
Solution Approach 1:
The finish layer uses composite materials combining conductive metals with dark-colored metal oxides. The conductive metals ensure low contact resistance while the metal oxide pigments provide the desired dark appearance, achieving both electrical performance and aesthetic requirements simultaneously
3Illumination intensity
If metal oxide coatings are used to achieve dark appearance, then the L* value decreases, but electrical conductivity and durability worsen
Solution Approach 1:
The patent resolves this contradiction by creating a composite finish layer where metal oxides (providing darkness) are combined with conductive metals (providing electrical conductivity and corrosion resistance). This composite approach allows each component to contribute its strengths, achieving dark appearance with maintained electrical performance and durability
Solution Approach 2:
The finish layer exhibits local quality by having different components distributed to perform different functions: metal oxide regions provide darkness while conductive metal regions provide electrical pathways. This spatial distribution of properties allows the coating to simultaneously achieve dark appearance and good conductivity
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 finish layer achieves a contact resistance of less than 1000 milliohms and a dark appearance with a CIE L* value of less than or equal to 60, enhancing the electrical contact's performance and appearance in devices like mobile devices.
Implementation Method 1
The finish layer may be applied to the electrical contact structure by a suitable deposition techniques, such as electrodeposition
Data Source
AI summary
An electrical contact comprising a layer of a dark electrically conductive finish layer is generally described.