Flexible Circuit Manufacturing with Pre-impregnated Dielectric
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Solution Overview
Problem
The existing manufacturing process for flexible printed circuits in smart cards is complex and costly due to the need for an additional adhesive layer between the electrically conductive material and the dielectric substrate, which complicates the lamination process and can result in resin flow into connection wells, compromising the connection quality.
Innovation Solution
A method that involves perforating the dielectric material before lamination with a pre-impregnated resin, eliminating the need for an additional adhesive layer, and using a prepreg with controlled creep properties to ensure stable adhesion and prevent resin flow into connection wells, allowing direct contact between the conductive material and the dielectric substrate during lamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a thermosetting adhesive layer is used to bond the conductive material with the dielectric material, then adhesion strength is improved, but the process complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts and eliminates the separate adhesive layer from the bonding system. Instead of using a distinct thermosetting adhesive layer between the conductive material and dielectric material, the invention uses a pre-impregnated dielectric material where the resin serves both as the bonding matrix and as the adhesive, thereby reducing process complexity while maintaining bonding strength
Solution Approach 2:
The patent merges the functions of the dielectric material and the adhesive into a single pre-impregnated material. The dielectric substrate is pre-impregnated with thermosetting resin that provides both structural support and bonding capability, eliminating the need for a separate adhesive layer and simplifying the manufacturing process
2Strength
If a thermosetting adhesive layer is used to bond the conductive material with the dielectric material, then adhesion strength is improved, but manufacturing cost increases
Solution Approach 1:
The patent removes the separate adhesive layer purchasing and application steps from the manufacturing process. By using pre-impregnated dielectric material, the invention eliminates the need to buy, store, and apply separate adhesive materials, thereby reducing manufacturing costs while maintaining bonding strength through the integrated resin system
Solution Approach 2:
The pre-impregnated dielectric material is self-sufficient in providing bonding capability. The thermosetting resin is already incorporated into the dielectric substrate during manufacturing, allowing the material to bond conductive layers without requiring external adhesive application processes, thereby reducing overall manufacturing complexity and cost
3Manufacturing precision
If the dielectric material is perforated after lamination, then connection wells are formed, but resin may flow into the wells and compromise connection quality
Solution Approach 1:
The patent performs the perforation operation before the lamination and resin curing processes. By creating connection wells in the dielectric material before applying conductive layers and curing the resin, the invention ensures that the wells are pre-formed and properly positioned, and the subsequent resin application does not cause deformation or unwanted flow into the wells, thereby maintaining connection quality
Solution Approach 2:
The patent inverts the conventional sequence of operations by perforating the dielectric material before lamination rather than after. This reverse sequencing prevents resin from flowing into wells during the lamination process, as the wells are already formed and the resin is applied in a controlled manner that does not compromise connection quality
4Adaptability or versatility
If a thin dielectric substrate is used to retain flexibility, then flexibility is improved, but structural integrity may be compromised
Solution Approach 1:
The patent employs composite material construction where a thin dielectric substrate is reinforced with conductive material layers and bonded through a pre-impregnated thermosetting resin system. The combination of the thin flexible substrate with the structurally sound conductive layers and cured resin matrix creates a composite structure that maintains both flexibility and structural integrity
Solution Approach 2:
The patent utilizes parameter changes in the thermosetting resin, which transitions from a flexible, processable state during lamination to a rigid, high-strength state after curing. This parameter change allows the thin dielectric substrate to achieve both flexibility during manufacturing and structural integrity after the resin cures, maintaining the balance between flexibility and strength
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 approach simplifies the manufacturing process, reduces costs, and ensures reliable electrical connections by preventing resin flow into connection wells, maintaining the structural integrity and adhesion properties at operating temperatures.
Implementation Method 1
a layer of dielectric material consisting of a pre-impregnated material... The sheet of electrically conductive material is laminated with the layer of dielectric material... while the first face of the layer of dielectric material is directly brought into contact with the first face of the sheet of electrically conductive material
Data Source
Figure 1~2c
Figure 2d~2g
Figure 2h~3
AI summary
The invention relates to a method for manufacturing a flexible circuit. It comprises providing a sheet of electrically conductive material (11) and a layer of dielectric material (50). It also comprises bringing the layer of dielectric material (50) directly into contact with the sheet of electrically conductive material (11) and laminating them together. The layer of dielectric material (50) is made of a pre-impregnated material. Thus, the sheet of electrically conductive material (11) can be laminated and bonded to the layer of dielectric material without the need for an additional adhesive layer. The invention also relates to a flexible smart card circuit manufactured using this method and a smart card module comprising such a flexible circuit.