Shield Case Grounding Through PCB Holes for Low Impedance
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Solution Overview
Problem
Existing wireless communication devices face challenges in maintaining low impedance between the ground layer and the shield case, which can lead to a decrease in shielding effectiveness when downsized, as the area of the ground layer land pattern is reduced.
Innovation Solution
The implementation of a printed circuit board with multiple conductive layers and through holes, combined with a shield case that has projecting portions inserted into these holes and electrically connected via solder, creating a low-impedance conduction path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the wireless communication device is downsized, then the device size is reduced, but the area of the ground layer land pattern is reduced making it difficult to secure sufficient area
Solution Approach 1:
The patent transitions from a two-dimensional ground connection (land pattern on surface) to a three-dimensional connection by forming through-holes that pass through the entire board thickness. This vertical dimension allows the ground connection to extend through the board, effectively increasing the connection area without increasing the surface footprint, thus resolving the contradiction between device downsizing and maintaining sufficient ground layer area.
Solution Approach 2:
The shield case is positioned to surround the circuit board, with the through-holes providing vertical penetration through the board structure. This nested configuration allows the ground connection to be embedded within the board thickness, maximizing the use of available space while maintaining adequate ground connection area despite reduced device dimensions.
2Volume of moving object
If the ground layer land pattern area is reduced, then the device can be downsized, but the impedance between the ground layer and the shield case increases
Solution Approach 1:
The through-holes create a vertical conduction path that extends through the entire board thickness, adding a third dimension to the ground connection. This multi-dimensional connection path reduces impedance by providing multiple parallel conduction routes (through the hole walls and solder connections) rather than relying solely on reduced two-dimensional land pattern area.
Solution Approach 2:
The patent changes the conduction path geometry from a surface-level connection to a through-depth connection. By forming holes that penetrate the entire board and filling them with conductive material and solder, the effective conduction cross-section is increased along the vertical axis, thereby reducing impedance even when the surface land pattern area is reduced for device downsizing.
3Volume of moving object
If the ground layer land pattern area is reduced, then the device can be downsized, but the shielding effect of the shield case decreases
Solution Approach 1:
The through-holes establish a vertical electromagnetic shield connection that extends through the board thickness, creating a continuous conductive path from the shield case to the ground layer. This three-dimensional shielding connection maintains effective electromagnetic interference protection even when the device is downsized and the surface land pattern area is reduced.
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 configuration effectively suppresses high impedance between the printed circuit board and the shield case, ensuring efficient electrostatic and electromagnetic shielding, while allowing for easy assembly and positioning, thus maintaining effective shielding even in downsized devices.
Implementation Method 1
at least one through hole passing through the at least one ground layer is formed in the printed circuit board, at least one projecting portion to be inserted into the at least one through hole is formed in a projecting manner in the shield case, and in a state of being inserted in the through hole, the projecting portion is electrically connected to the at least one ground layer via solder
Data Source
AI summary
An electronic device that is capable of keeping the impedance (ground impedance) between a printed circuit board and a shield case low. The electronic device includes a printed circuit board that has ground layer(s) which is conductive and is provided at a location in the thickness direction of the printed circuit board, and the shield case which is disposed on one side of the printed circuit board and consists of a hollow body that has conductivity. A through hole(s) passing through the ground layer is formed in the printed circuit board. A projecting portion(s), which is inserted into the through hole(s), is formed in a projecting manner in the shield case. In a state of being inserted in the through hole(s), the projecting portion(s) is electrically connected to the ground layer via solder.