Circuit Board Barrier Layer Blocks Copper Migration
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Solution Overview
Problem
In touch display products, the design of circuit boards often fails to meet environmental reliability requirements, leading to verification test failures and potential performance risks in mass production due to copper signal line migration and short-circuiting with electromagnetic shielding layers.
Innovation Solution
A circuit board design featuring a stacked structure with conductive layers, insulating layers, barrier layers, and electromagnetic shielding layers, where the barrier layer is strategically positioned between the insulating and electromagnetic shielding layers to prevent copper migration, and adhesive layers connect circuit board units to ensure insulation and electrical connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper signal lines are used in circuit boards, then electrical connectivity is achieved, but copper migration occurs causing short circuits with electromagnetic shielding layers
Solution Approach 1:
The patent introduces a barrier layer as an intermediary substance between the copper signal lines and the electromagnetic shielding layer. This barrier layer prevents direct contact and copper ion migration while maintaining the necessary electrical insulation, thus resolving the harmful effect of copper migration without compromising electrical connectivity.
Solution Approach 2:
The patent extracts the problematic copper signal lines from direct proximity to the electromagnetic shielding layer by introducing insulating layers and barrier layers. This separation removes the source of copper migration harm while preserving the functional requirements of the circuit board.
2Object-affected harmful factors
If electromagnetic shielding layers are added to block interference, then electromagnetic compatibility is improved, but copper migration causes short circuits between signal lines and shielding layers
Solution Approach 1:
The barrier layer serves as a protective intermediary that allows the electromagnetic shielding layer to perform its shielding function while preventing copper ions from migrating to the shielding layer and causing short circuits. This resolves the contradiction by maintaining both shielding effectiveness and circuit reliability.
Solution Approach 2:
The patent employs composite material structures combining insulating layers, barrier layers, and electromagnetic shielding layers. This composite approach integrates multiple functions (insulation, copper migration prevention, and electromagnetic shielding) into a unified structure that resolves the contradictions between shielding effectiveness and reliability.
3Reliability
If multiple layers are added to prevent copper migration, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent segments the circuit board structure into distinct functional layers (insulating layers, barrier layers, electromagnetic shielding layers) with clearly defined roles. This segmentation allows each layer to perform its specific function efficiently while maintaining overall system reliability, and the modular nature facilitates manufacturing and quality control.
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 solution effectively blocks copper migration, preventing short circuits and ensuring reliable performance, thereby addressing issues of black, blurred, or splash screens in display devices by maintaining circuit integrity and enhancing manufacturing reliability.
Implementation Method 1
copper signal line migration and short-circuiting with electromagnetic shielding layers
Data Source
AI summary
A circuit board includes at least one circuit board unit sequentially stacked in a thickness direction of the circuit board, an insulating layer, an electromagnetic shielding layer, and a barrier layer. The circuit board unit includes a substrate layer, and two conductive layers respectively disposed on two opposite sides of the substrate layer in a thickness direction of the substrate layer, and each of the conductive layers includes a plurality of signal lines. The insulating layer is located on a side of an outermost conductive layer away from the substrate layer. The electromagnetic shielding layer is located on a side of the insulating layer away from the substrate layer. The barrier layer is located between the electromagnetic shielding layer and the outermost conductive layer. The barrier layer at least covers a plurality of signal lines in the outermost conductive layer.