Circuit Assembly Ground Connection via Through-Hole and Conductive Paste
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Solution Overview
Problem
Conventional methods for connecting a ground pattern of a substrate to a ground potential outside the substrate reduce the area available for mounting components due to the use of screws, which also generate stress in the substrate.
Innovation Solution
A circuit assembly that includes a substrate with a ground pattern and a through-hole, a metal member inserted into the through-hole for electrical connection, a heat dissipation member made of metal connected to an external ground potential, and conductive paste to connect the metal member and the heat dissipation member, eliminating the need for screws and increasing the contact area for reduced electrical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a screw is used to connect the ground pattern to the ground potential, then the electrical connection is achieved, but the component mounting area is reduced due to the screw head occupying space on the substrate surface
Solution Approach 1:
The invention extracts the screw head from the substrate surface by routing the fastening function through a through-hole. The metal member extends through the substrate thickness, allowing the screw to fasten from the bottom side rather than occupying surface area, thus separating the electrical connection function from the mechanical fastening function in terms of spatial occupation.
Solution Approach 2:
The invention moves the screw head position from the 2D substrate surface to the 3D space below the substrate by utilizing the through-hole depth dimension. This dimensional transition allows the screw head to be positioned on the opposite side of the substrate, eliminating its projection onto the component mounting area.
2Reliability
If a screw is used to fasten the ground pattern to the sheet metal piece, then the electrical connection is achieved, but stress is generated in the substrate due to the fastening process
Solution Approach 1:
The metal member acts as an intermediary element between the substrate and the screw. It provides a dedicated mechanical interface that absorbs the fastening stress, preventing direct transmission of stress to the substrate. The metal member's threaded portion engages with the through-hole, creating a stress-distributing connection that protects the substrate from damage.
3Reliability
If conductive paste is used to connect the metal member and the heat dissipation member, then the contact area is increased and electrical resistance is reduced, but the assembly complexity increases
Solution Approach 1:
The invention changes the physical state of the conductive material from solid (screw contact) to paste (deformable material). The paste can be applied as a thin layer that conforms to surface irregularities, creating large contact area between the metal member and heat dissipation member. This parameter change from discrete point contact to continuous surface contact reduces electrical resistance while the paste's deformability accommodates manufacturing tolerances, simplifying assembly.
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
Enables connection of the ground pattern to the ground potential without reducing the component mounting area, suppresses stress on the substrate, and enhances thermal conductivity and electrical contact by using conductive paste for connection.
Implementation Method 1
conductive paste that connects the metal member and the heat dissipation member
Implementation Method 2
since the metal member and the heat dissipation member are connected by the conductive paste, it is possible to increase an actual contact area as compared with contact between solids, thereby reducing electrical resistance and suppressing conduction loss
Data Source
AI summary
A circuit assembly includes: a substrate formed with a ground pattern and a through-hole; a metal member that is inserted into the through-hole and electrically connected to the ground pattern; a heat dissipation member made of metal, that is overlaid on the substrate and can be connected to an external ground potential; and conductive paste that connects the metal member and the heat dissipation member.