Shielding Film Hard Soft Layer Structure
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Solution Overview
Problem
Existing shielding films for printed circuit boards face issues with abrasion resistance, blocking resistance, and cracking due to their softness and adhesion properties, leading to breakage and attachment problems during manufacturing processes.
Innovation Solution
A shielding film with a layered structure comprising a hard layer and a soft layer, where the hard layer provides abrasion and blocking resistance, and the soft layer offers cushioning to prevent cracking, while the metal layer is protected from breakage by the hard layer, and the film can be made thin for flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cover film is made of engineering plastic such as PPS with thick thickness or strong stiffness, then the shielding film has good blocking resistance, but the flexibility of the cover film deteriorates
Solution Approach 1:
The cover film is segmented into multiple layers: a hard layer (PPS) providing blocking resistance and a soft layer (polyimide) providing flexibility. This segmentation allows each layer to perform its specific function independently, resolving the contradiction between blocking resistance and flexibility.
Solution Approach 2:
The cover film uses composite materials by combining PPS (hard layer) and polyimide (soft layer). This composite structure integrates the advantages of both materials: PPS provides excellent blocking resistance while polyimide provides flexibility, thus resolving the technical contradiction.
2Ease of operation
If the cover film is made soft to improve flexibility, then the flexibility is improved, but the abrasion resistance and blocking resistance deteriorate
Solution Approach 1:
The cover film is divided into a hard layer for abrasion resistance and a soft layer for flexibility. The hard layer (PPS) protects against abrasion while the soft layer (polyimide) provides flexibility, resolving the contradiction between these two properties.
Solution Approach 2:
By using composite materials with PPS as the hard layer and polyimide as the soft layer, the cover film achieves both abrasion resistance from PPS and flexibility from polyimide, simultaneously satisfying both requirements.
3Reliability
If the cover film has strong adhesion, then the shielding film adheres well to the substrate, but the cover film attaches to conveyor jigs or belts during heated processes
Solution Approach 1:
The adhesion property is localized to where needed: the shielding film has strong adhesion to the substrate through its adhesive layer, but the hard layer's low friction prevents unwanted attachment to conveyor equipment. This local differentiation of properties resolves the contradiction.
Solution Approach 2:
The low friction coefficient of the hard layer, which might seem to reduce adhesion, is converted into a benefit by preventing attachment to conveyor equipment during heated processes. The adhesion to substrate is maintained through the adhesive layer while the hard layer's properties prevent harmful attachments.
4Reliability
If the shielding film is heated and pressed for adhesion, then the adhesive bonding is improved, but the soft cover film causes dents on insulation removed portions leading to metal layer breakage
Solution Approach 1:
The cover film is segmented into a hard layer and a soft layer. The hard layer provides structural support and prevents dents during heating and pressing, while the soft layer allows for cushioning and conformability. This segmentation protects the metal layer from breakage while maintaining adhesive bonding.
Solution Approach 2:
The composite structure of hard layer (PPS) and soft layer (polyimide) allows the hard layer to resist denting during heated pressing, protecting the metal layer from breakage, while the soft layer provides cushioning. This resolves the contradiction between achieving adhesive bonding and preventing metal layer breakage.
Data Source
Figure 1(a)~1(c)
Figure 2(a)~2(b)
Figure 3(a)~3(c)
AI summary
The invention includes a shielding film, which does not have breakage of a metal layer, and has excellent abrasion resistance and blocking resistance, and does not crack. The cover film 7 is provided on one surface of a separation film 6a, and an adhesive layer 8a is formed on the surface of the cover film 7 opposite to the separation film 6a via the metal layer. The cover film 7 has at least one hard layer 7a and at least one soft layer 7b, and the surface of the cover film 7 facing the separation film 6a is composed of the hard layer 7a.