Flexible Circuit Board with Segmented Resin Layers
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Solution Overview
Problem
Flexible circuit boards made of polyimide have low accuracy and poor electrical characteristics, while those made of thermoplastic resin have lower durability and are prone to failure under stress, limiting their application in flexible circuit boards requiring entire surface flexibility.
Innovation Solution
A flexible circuit board design comprising a first substrate portion with bonded resin layers for durability and a second substrate portion with intermolecularly bonded thermoplastic resin layers for accuracy, where the first substrate portion absorbs stress and the second substrate portion maintains high electrical accuracy and water resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a flexible circuit board is made of polyimide, then manufacturing cost is reduced, but accuracy of electrode shape and accuracy of circuit board shape are low
Solution Approach 1:
The flexible circuit board is divided into multiple resin layers (first resin layer, second resin layer, third resin layer) with different functions. The first and third resin layers provide flexibility and durability, while the second resin layer ensures accurate electrode shape and electrical characteristics. This segmentation allows each layer to optimize its specific function without compromising overall performance.
Solution Approach 2:
The patent uses a composite structure combining different resin materials with complementary properties. The polyimide resin layers provide flexibility and durability, while the thermoplastic resin layer provides dimensional stability and accurate electrode formation. This composite approach resolves the contradiction between low-cost flexibility and manufacturing precision.
2Manufacturing precision
If a flexible circuit board is made of thermoplastic resin, then accuracy of electrode shape and accuracy of circuit board shape are improved, but durability is lower
Solution Approach 1:
The circuit board is segmented into durability-providing layers (first and third resin layers made of polyimide) and precision-providing layers (second resin layer made of thermoplastic resin). This allows the thermoplastic resin to ensure accurate electrode shape without being the sole structural component, thus protecting it from excessive stress and improving overall durability.
Solution Approach 2:
Different regions of the circuit board have different material compositions optimized for their specific functions. The regions requiring flexibility and stress resistance use polyimide resin, while regions requiring precise electrode formation use thermoplastic resin. This local optimization resolves the contradiction between precision and durability.
3Manufacturing precision
If a rigid-flexible circuit board is used, then accuracy of electrode shape and accuracy of circuit board shape are improved, but the entire surface flexibility is lost
Solution Approach 1:
The circuit board is segmented into multiple flexible resin layers bonded together, with each layer contributing to overall flexibility. The multilayer structure allows the entire board to bend and flex while maintaining accurate electrode shapes through the dimensional stability provided by the thermoplastic resin layer.
Solution Approach 2:
The patent creates a composite flexible structure where polyimide resin layers provide flexibility and durability, while the thermoplastic resin layer provides dimensional stability. This composite flexible structure eliminates the need for rigid portions while maintaining manufacturing precision.
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 design significantly reduces the occurrence of failures such as fracture or breaking, while ensuring consistently good electrical characteristics and maintaining the flexibility of the circuit board.
Implementation Method 1
a first substrate portion including a plurality of resin layers bonded together with an adhesive
Implementation Method 2
a second substrate portion including a plurality of resin layers integrated with one another by intermolecular bonding of a thermoplastic resin
Data Source
AI summary
A flexible circuit board whose entire surface has flexibility includes a first substrate portion and a second substrate portion that are adjacent to each other and electrically connected to each other in a planar direction of the flexible circuit board. The first substrate portion includes a plurality of resin layers, which are bonded together with an adhesive, and the second substrate portion includes a plurality of resin layers, which are integrated with one another by intermolecular bonding of a thermoplastic resin.