Probe Plunger Barrel Bonding Narrow Pitch

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Solution Overview

Problem

The existing probe structures, where the plunger and barrel are fixed by spot welding, experience outward bulging due to pressure, necessitating increased spacing to prevent contact, which limits the arrangement of probes with a narrow pitch.

Innovation Solution

A probe design featuring a rod-shaped plunger and tube-shaped barrel connected using a conductive first fixing member with a lower melting point, which fills the gap between them without voids, allowing for a consistent and narrow pitch arrangement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the plunger and barrel are fixed by spot welding, then the plunger and barrel are securely connected, but the barrel bulges outward due to welding pressure

Engineering Contradiction:

Improveconnection strengthVSAvoidbarrel shape

Core Design Contradiction:

StrengthVSShape

Solution Approach 1:

The patent replaces the mechanical spot welding process with a thermal bonding process using a conductive adhesive. Instead of applying mechanical pressure through welding electrodes that causes barrel bulging, the invention uses heat-activatable adhesive that bonds the plunger to the barrel without mechanical compression, thereby eliminating the shape deformation while maintaining connection strength.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the bonding mechanism from mechanical (spot welding with pressure) to chemical-thermal (adhesive bonding with heat activation). By changing the bonding parameters from high mechanical pressure to controlled thermal activation, the barrel bulging problem is eliminated while achieving secure connection between plunger and barrel.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the spacing between probes is increased to prevent contact, then probe contact is avoided, but the pitch between probes cannot be narrowed

Engineering Contradiction:

Improveprobe contact preventionVSAvoidprobe pitch

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The patent converts the potential harm of barrel deformation into a benefit by using the deformation space to accommodate the conductive adhesive layer. The adhesive fills the gap created by the bonding process, transforming what would be a defect (bulging) into a functional feature that enables narrow pitch arrangement while maintaining reliable probe operation.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Shape

If a conductive fixing member with lower melting point is used to fix the plunger to the barrel, then the plunger and barrel are fixed without bulging, but the fixing member must be melted to achieve fixation

Engineering Contradiction:

Improvebarrel shape consistencyVSAvoidfixing process complexity

Core Design Contradiction:

ShapeVSEase of manufacture

Solution Approach 1:

The invention utilizes phase transition (melting and solidification) of the conductive adhesive as the bonding mechanism. The adhesive is applied in solid form, heated to melt and flow into the interface between plunger and barrel, then cooled to solidify and create a strong bond. This phase transition approach enables fixation without mechanical pressure, preventing barrel bulging while providing a manufacturable process.

Inventive Principle:

Principle #36Phase transitions

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 the arrangement of probes with a narrow pitch without bulging, improving the manufacturing method and maintaining electrical connectivity by filling the gap between the plunger and barrel with the conductive fixing member.

Implementation Method 1

melting the first fixing member to fix the plunger to the barrel

Methodology Applied

Scientific EffectMelting: Melting

Implementation Method 2

The plunger and barrel can be fixed by spot welding

Methodology Applied

Scientific EffectWelding: Welding

Data Source

PatentEP3633391B1probe

Publication Date: 2023.08.02 NIHON MICRONICS KK

Figure 1~2
Figure 3~4
Figure 5(a)~5(c)

AI summary

A probe includes: a rod-shaped plunger (11) including a tip section (111) and an insertion section (112) connected to the tip section (111); a tube-shaped barrel (12) in which the insertion section (112) of the plunger (11) is located inside; and a conductive first fixing member (131) which is located in an area where the plunger (11) and the barrel (12) face each other and is configured to fix the plunger (11) to the barrel (12), the first fixing member (131) having a lower melting point than that of the material of both of the plunger (11) and the barrel (12). The gap between the plunger (11) and the barrel (12) is filled with the first fixing member (131) without any voids in a cross section of the probe in an area where the plunger (11) and the barrel (12) overlap each other, including the area where the first fixing member (131) is located.