Transparent Metal Shielding Film Adhesion and Stability
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Solution Overview
Problem
Shielding films for printed wiring boards face challenges in maintaining transparency and environmental resistance, especially in high-temperature and high-humidity environments, and require improved electrical connection stability without compromising shielding performance.
Innovation Solution
An electromagnetic wave shielding film with a specific layer structure comprising a first insulating layer, a transparent metal layer, a second insulating layer, and a conductive adhesive layer, where the second insulating layer is 10 to 500 nm thick, containing spherical conductive particles with a median size of 3 to 50 μm and a content ratio of 5 to 20 mass%, enhancing adhesion, stability, and environmental resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the metal layer is thinned to improve transparency, then transparency is improved, but environmental resistance deteriorates and the metal layer becomes cloudy in high-temperature and high-humidity environments
Solution Approach 1:
The patent uses a composite structure consisting of a transparent metal layer (such as ITO, IZO, or ZnO) combined with specific insulating layers. The metal layer thickness is controlled at 5-50 nm to maintain transparency while the composite structure with insulating layers protects against environmental degradation, preventing clouding in high-temperature and high-humidity conditions.
2Reliability
If the amount of conductive particles in the anisotropic conductive pressure-sensitive adhesive sheet is increased to improve electrical connection stability, then electrical connection stability is improved, but transparency decreases and environmental resistance is not compensated
Solution Approach 1:
The patent changes the particle size parameter of conductive particles to a specific range (median diameter 3-50 μm) and controls the content ratio (5-20 mass%). This parameter optimization achieves stable electrical connection while maintaining transparency and improving environmental resistance, avoiding the need to increase particle amount which would reduce transparency.
3Ease of operation
If a conventional anisotropic conductive pressure-sensitive adhesive sheet is used to enable adhesion under mild conditions, then ease of operation is improved, but electrical connection stability becomes unstable
Solution Approach 1:
The patent optimizes the particle size distribution (median diameter 3-50 μm) and content ratio (5-20 mass%) of conductive particles in the adhesive layer. This parameter control enables the adhesive to function under mild conditions while maintaining stable electrical connection, resolving the instability issue of conventional adhesive sheets.
4Reliability
If the thickness of the second insulating layer is increased to improve environmental resistance, then environmental resistance is improved, but manufacturing complexity increases
Solution Approach 1:
The patent specifies the thickness of the second insulating layer within the range of 10-500 nm. This parameter optimization provides sufficient environmental resistance while avoiding excessive thickness that would increase manufacturing complexity. The controlled thickness ensures proper protection of the transparent metal layer without over-engineering the structure.
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 shielding film achieves excellent electrical connection stability, transparency, and environmental resistance, allowing easy adhesion to printed wiring boards while maintaining effective shielding performance, even in challenging environmental conditions.
Implementation Method 1
a shielding film used by being bonded to a printed wiring board includes a shielding layer such as a metal layer
Implementation Method 2
the conductive adhesive layer contains a binder component and spherical conductive particles, a median size of the spherical conductive particles is 3 to 50 μm, and a content ratio of the spherical conductive particles is 5 to 20 mass %
Implementation Method 3
a thickness of the second insulating layer is 10 to 500 nm
Implementation Method 4
a conductive adhesive sheet provided on a surface of the shielding layer
Data Source
AI summary
Provided is an electromagnetic wave shielding film capable of easily adhering to an object, excellent in electrical connection stability, and excellent in transparency, shielding performance, and environmental resistance. The electromagnetic wave shielding film of the present invention has a first insulating layer, a transparent metal layer, a second insulating layer, and a conductive adhesive layer laminated in this order, in which a thickness of the second insulating layer is 10 to 500 nm, the conductive adhesive layer contains a binder component and spherical conductive particles, a median size of the spherical conductive particles is 3 to 50 μm, and a content ratio of the spherical conductive particles is 5 to 20 mass % with respect to 100 mass % of the conductive adhesive layer.