Blind-Hole Terminal Anchoring for PCB Mounting Reliability
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Solution Overview
Problem
Conventional electronic component mounting structures, such as through-hole and surface mounting, face limitations in circuit density and connection reliability due to terminal displacement and stress issues caused by thermal expansion differences and external forces.
Innovation Solution
An electronic component mounting structure featuring terminals with a first portion soldered to lands on a printed circuit board and a second portion anchored in a blind hole, preventing displacement during solder hardening and allowing increased contact area and reliability, while enabling higher circuit density by allowing components to be mounted on both sides of the board.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If through-hole mounting structure is used, then connection reliability between terminals and lands is improved, but circuit density of the printed circuit board is reduced
Solution Approach 1:
The terminal is divided into two distinct portions: a first terminal portion that contacts the land on the front surface, and a second terminal portion that extends into the blind hole. This segmentation allows each portion to serve a specific function - the first portion ensures electrical connection while the second portion provides mechanical anchoring, thereby maintaining connection reliability while enabling higher circuit density through blind-hole mounting.
Solution Approach 2:
The invention transitions from traditional through-hole mounting where terminals pass completely through the board to blind-hole mounting where terminals are contained within holes that do not penetrate the back surface. This dimensional change allows the back surface to be utilized for additional components, significantly increasing circuit density while maintaining connection reliability through the anchored terminal structure.
2Productivity
If blind-hole mounting structure is used, then circuit density of the printed circuit board is increased, but connection reliability between terminals and lands is reduced
Solution Approach 1:
The second terminal portion is preliminarily positioned within the blind hole before the soldering process. This preliminary anchoring action prevents terminal displacement during solder hardening and subsequent thermal cycling, ensuring connection reliability is maintained even with the reduced contact area inherent in blind-hole mounting.
Solution Approach 2:
The blind hole provides a curved, enclosed space that contains and anchors the second terminal portion. This curved geometry ensures the terminal remains properly positioned and prevents displacement, thereby maintaining connection reliability while enabling the circuit density benefits of blind-hole mounting.
3Productivity
If surface mounting structure is used, then circuit density of the printed circuit board is increased, but connection reliability between terminals and lands is reduced due to terminal displacement
Solution Approach 1:
The second terminal portion extending into the blind hole serves as a preliminary anti-action measure against terminal displacement. By providing mechanical anchoring before the solder hardens, it counteracts the displacement forces that occur during reflow soldering and subsequent thermal cycling, thereby ensuring connection reliability is maintained in the high-density surface mounting configuration.
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 enhances connection reliability and circuit density by anchoring terminals within blind holes, reducing stress and displacement risks, and allowing for secure mounting of additional components on the back surface of the board.
Implementation Method 1
The first terminal portion is soldered to the land portion
Data Source
AI summary
An electronic component mounting structure includes a board and an electronic component mounted on a surface of the board. The board includes lands. The electronic component includes a body and terminals extending from the body. Each terminal is electrically connected to a corresponding one of the lands of the board. The terminal has a first terminal portion extending along the surface of the board and a second terminal portion extending toward the surface of the board. Each land includes a land portion electrically soldered to the first terminal portion and a blind hole for receiving the second terminal portion. The first terminal portion is soldered to the land portion in a reflow process under the condition that the second terminal portion is inserted in the blind hole.