Soldered Contact Structure That Preserves Elastic Deformation

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Solution Overview

Problem

Existing contacts face challenges in maintaining elasticity and a broad elastically deformable range, especially when reduced in size to accommodate increased component density on substrates, leading to reduced elasticity and a narrower deformable range.

Innovation Solution

A contact with a thin, elastically conductive plate member featuring a base portion and a movable portion, where the connecting portion has reduced solder wettability to prevent solder restriction, and a through-hole design that directs solder flow away from the connecting area, ensuring the contact remains deformable and securely bonded to the substrate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the size of the contact is reduced to accommodate increased component density, then the device size is reduced, but the elasticity of the contact is reduced and the elastically deformable range is reduced

Engineering Contradiction:
Improvecontact sizeVSAvoidelasticity
Core Design Contradiction:
Volume of moving objectVSStability of the object's composition

Solution Approach 1:

The patent applies different surface treatments to different regions of the contact. The connecting portion has reduced solder wettability (through oxide formation or selective plating removal) while the base portion maintains high solder wettability. This local differentiation allows the small contact to be securely bonded at the base while preserving elasticity in the connecting portion, resolving the contradiction between miniaturization and elasticity maintenance.

Inventive Principle:
Principle #3Local quality

2Strength

If the contact is securely bonded to the substrate, then the bonding strength is improved, but the elastic deformability of the connecting portion is restricted

Engineering Contradiction:
Improvebonding strengthVSAvoidelastic deformability
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent creates a local quality difference in solder wettability between the base portion (high wettability for strong bonding) and the connecting portion (low wettability to prevent solder attachment). This ensures that solder is confined to the base portion, providing secure bonding without restricting the elastic deformability of the connecting portion.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The contact is functionally segmented into a base portion for bonding and a connecting portion for elastic deformation. By controlling solder distribution through differential wettability, the patent effectively separates the bonding function from the elastic deformation function, allowing both to operate optimally without interfering with each other.

Inventive Principle:
Principle #1Segmentation

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 maintains the contact's elasticity and prevents solder attachment to the connecting portion, allowing for effective electrical connection while supporting automatic mounting and reducing the risk of peeling or deformation.

Implementation Method 1

An inner peripheral surface of the through-hole is subjected to a treatment for improving solder wettability

Methodology Applied
Scientific EffectSolder wettability: Wetting

Implementation Method 2

The movable portion is configured to be elastically deformable with respect to the base portion

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

the contact is configured to be bonded to a first member by soldering

Methodology Applied
Scientific EffectSoldering: Soldering

Data Source

PatentEP3758153B1contact
Publication Date: 2024.11.20 KITAGAWA INDS
  • EP3758153B1 patent drawingFigure 1
  • EP3758153B1 patent drawingFigure 2A~2F
  • EP3758153B1 patent drawingFigure 3

AI summary

Problem To provide a contact capable of suppressing reduction of elasticity. Solution A contact includes a thin plate member having elasticity and conductivity, is disposed between a first member and a second member, and electrically connects the first member and the second member via the thin plate member, and the contact includes a base portion and a movable portion. The base portion has a bonding surface to be bonded to the first member by soldering. The movable portion includes: a contact portion that contacts with the second member; and a connecting portion that connects to the base portion, and is configured to be elastically deformable with respect to the base portion. The connecting portion is gradually separated from the first member. A predetermined range from a connecting position of the connecting portion with the base portion is lower in solder wettability than the bonding surface.