Flexible Wiring Board Ground Pattern for EMI Shielding
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Solution Overview
Problem
As communication speeds in electronic apparatuses increase, they generate more electromagnetic noise, which existing flexible wiring boards struggle to effectively suppress, leading to potential malfunctions and transmission errors.
Innovation Solution
A flexible wiring board design featuring an electroconductive layer with specific openings and linear portions that form acute or obtuse angles with the signal lines, creating a shielding effect to block electromagnetic noise, particularly effective in high-frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If communication speed is increased to enable high-capacity data communication, then data transmission capacity is improved, but electromagnetic noise generated from signal wiring increases
Solution Approach 1:
The patent utilizes the electromagnetic noise generated by high-speed signal transmission and converts it into a beneficial effect by designing the ground pattern with linear portions that generate canceling electromagnetic fields. The linear portions extending at acute or obtuse angles from connection portions in openings of the ground layer create opposing electromagnetic fields that neutralize the harmful radiation noise, thereby converting the harmful electromagnetic energy into a protective mechanism that maintains signal integrity during high-capacity data communication
2Object-generated harmful factors
If a ground layer with openings is used to reduce radiation noise, then electromagnetic noise is suppressed, but the shielding effectiveness is insufficient for high-speed communication
Solution Approach 1:
The patent applies local quality by creating distinct regions within the ground layer with different functional characteristics. The ground layer includes openings with linear portions that have specific geometric properties (acute or obtuse angles) localized at critical positions near signal lines. These localized structural modifications create enhanced electromagnetic field cancellation effects precisely where needed, rather than using a uniform ground layer design throughout the entire circuit board
3Ease of manufacture
If the electroconductive layer uses a conventional ground pattern, then manufacturing is simple, but radiation noise cannot be sufficiently suppressed
Solution Approach 1:
The patent segments the ground layer into distinct functional regions: openings with linear portions, connection portions, and continuous ground areas. This segmentation allows each region to perform its specific function - the linear portions in openings generate targeted canceling fields, the connection portions provide electrical connectivity, and the continuous areas maintain ground potential. Despite this complex segmentation, the pattern can be manufactured using standard PCB fabrication processes, maintaining ease of manufacture while achieving superior noise suppression
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 electromagnetic noise, enhancing communication reliability and preventing malfunctions in high-speed data transmission, while maintaining flexibility and functionality.
Implementation Method 1
an electroconductive layer that is disposed to face the signal line... creating a shielding effect to block electromagnetic noise
Data Source
AI summary
A flexible wiring board includes a signal line that transmits a signal and an electroconductive layer that is disposed to face the signal line, wherein the electroconductive layer includes a first portion in which a plurality of openings are provided, and a linear second portion that is formed in at least one of the plurality of openings, that has, at one end thereof, a connection portion connected to the first portion, and whose other end is an open end, where the connection portion is disposed in the second portion on a sending side in a transmission direction of a signal through the signal line. An angle between a direction along the transmission direction of the signal and an extension direction of the second portion from the connection portion toward the open end is an acute angle or an obtuse angle.