Flexible Circuit Board Layout for Reduced Signal Crosstalk

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Solution Overview

Problem

The challenge of integrating multiple signal lines on flexible printed circuits, such as those for display and touch signals, leads to increased wiring complexity and difficulty in manufacturing due to the need for multiple layers and additional shielding to prevent signal crosstalk, complicating the manufacturing process.

Innovation Solution

A flexible printed circuit design comprising a main sub-circuit board and a transfer sub-circuit board, with specific wiring configurations and connections that allow for signal transmission without intersecting paths, reducing the need for additional shielding layers and simplifying the manufacturing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If multiple signal lines are integrated on flexible printed circuits, then wiring density increases, but wiring complexity and manufacturing difficulty increase

Engineering Contradiction:
Improvewiring densityVSAvoidwiring complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The flexible printed circuit is divided into a first flexible circuit board and a second flexible circuit board that are electrically connected. This segmentation allows signal lines to be distributed across separate boards, reducing the wiring complexity on each individual board while maintaining high overall wiring density through the interconnected system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a single-plane wiring layout to a three-dimensional interconnected structure by stacking multiple flexible circuit boards. This dimensional change enables signal lines that would otherwise need to cross on the same plane to be routed on different boards, reducing complexity while increasing effective wiring density.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If multiple layers and shielding are added to prevent signal crosstalk, then signal transmission reliability improves, but manufacturing process complexity increases

Engineering Contradiction:
Improvesignal transmission reliabilityVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

By separating the circuit into multiple independent flexible circuit boards, the patent reduces signal crosstalk between different signal lines that would otherwise require additional shielding layers. This segmentation approach maintains signal transmission reliability by providing physical isolation between signals without increasing manufacturing complexity through additional layers.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses electrical connection structures (such as connectors or welding points) as intermediaries to connect the first and second flexible circuit boards. These intermediaries provide reliable signal transmission between boards while the physical separation acts as natural shielding, avoiding the need for complex multi-layer shielding structures.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If additional functional layers are added for shielding, then signal crosstalk prevention improves, but device flexibility and ease of production deteriorate

Engineering Contradiction:
Improvesignal crosstalk preventionVSAvoiddevice flexibility
Core Design Contradiction:
Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The patent achieves signal crosstalk prevention through spatial segmentation of circuit functions across multiple flexible circuit boards rather than adding shielding layers. This approach maintains the inherent flexibility of each individual board while providing the necessary isolation between different signal paths, thus preserving device adaptability and ease of production.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3920670B1Flexible circuit board and manufacturing method therefor, and electronic apparatus module and electronic apparatus
Publication Date: 2025.08.06 BOE TECHNOLOGY GROUP CO LTD
  • EP3920670B1 patent drawingFigure 1~2
  • EP3920670B1 patent drawingFigure 3A~3B
  • EP3920670B1 patent drawingFigure 4A~5A

AI summary

Disclosed are a flexible circuit board and a manufacturing method therefor, and an electronic apparatus module and an electronic apparatus. The flexible circuit board (10) comprises a main body sub circuit board (100) and an adapter sub circuit board (200), wherein the main body sub circuit board (100) comprises a first adapter end (101), a first wiring portion (102) and a second wiring portion (103), and the first wiring portion (102) and the second wiring portion (103) are spaced apart from each other and are respectively electrically connected to a first group of first contact pads (101A) of the first adapter end (101) and a second group of first contact pads (101B) thereof; the adapter sub circuit board (200) comprises a second adapter end (201) and a third wiring portion (202) for a first functional wiring, and the third wiring portion (202) electrically connects a first group of second contact pads (201A) of the second adapter end (201) to a second group of second contact pads (201B) thereof; and the adapter sub circuit board (200) is configured to be mounted on the main body sub circuit board (100) by means of respectively electrically connecting the first group of second contact pads (201A) of the second adapter end (201) and the second group of second contact pads (201B) thereof to the first group of first contact pats (101A) of the first adapter end (101) and the second group of first contact pads (201B) thereof. The flexible circuit board (10) has a simple wiring layerout and can be easily manufactured.