Hermetic Ferrule Assembly With Laser-Bonded Dielectric Substrate

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Solution Overview

Problem

Existing hermetic seal technologies for devices with dielectric and metallic components face challenges in bonding, requiring high-temperature processes that cause thermal stress and limit design flexibility, and often necessitate smooth and clean bonding surfaces, complicating the attachment of housings and feedthrough assemblies.

Innovation Solution

A hermetic assembly that includes a ferrule with a flange welded to a patterned layer on a dielectric substrate, allowing for a hermetic seal without the need for polishing or weld rings, enabling thinner housing sidewalls and providing more space for electronic components, while maintaining a conductive pathway and protecting the substrate from external loads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high-temperature bonding processes are used to join dielectric and metallic components, then hermetic seal integrity is improved, but thermal stress increases and design flexibility is reduced

Engineering Contradiction:
Improvehermetic seal integrityVSAvoidthermal stress
Core Design Contradiction:
ReliabilityVSStress or pressure

Solution Approach 1:

The bonding process is segmented into two distinct stages: first, a low-temperature laser bond joins the patterned layer to the dielectric substrate; second, a separate welding process attaches the ferrule flange to the patterned layer. This segmentation allows each bonding interface to be optimized independently, avoiding the need for high-temperature processing that would subject the entire assembly to thermal stress.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the temperature parameter of the bonding process from traditional high-temperature (required for glass or ceramic sealing) to low-temperature laser bonding. This parameter change enables the use of materials and designs that would be incompatible with high-temperature processing, thereby reducing thermal stress while maintaining hermetic seal integrity.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If traditional hermetic sealing methods are used, then seal reliability is improved, but manufacturing complexity increases due to polishing and weld ring requirements

Engineering Contradiction:
Improveseal reliabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention extracts and eliminates the need for polishing operations and weld rings from the hermetic sealing process. By using laser bonding to directly attach the patterned layer to the dielectric substrate, the complex surface preparation and additional components required by traditional methods are removed, simplifying manufacturing while maintaining seal reliability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces mechanical bonding methods (which require polished surfaces and weld rings) with laser bonding technology. This substitution eliminates the need for mechanical surface preparation and additional sealing components, reducing manufacturing complexity while achieving equivalent or superior seal reliability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Strength

If conventional ferrule attachment methods are used, then structural integrity is improved, but housing thickness increases reducing space for electronic components

Engineering Contradiction:
Improvestructural integrityVSAvoidhousing volume
Core Design Contradiction:
StrengthVSVolume of moving object

Solution Approach 1:

The invention changes the attachment geometry by extending the ferrule with a flange that bonds to the patterned layer on the dielectric substrate. This dimensional change allows the ferrule to be securely attached without requiring thick housing sidewalls, as the bonding surface is distributed across the patterned layer rather than requiring bulk material thickness for structural integrity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 simplifies the attachment process, reduces thermal stress, and enhances design flexibility by allowing bonding on one side of the dielectric substrate, while maintaining a stable conductive pathway and protecting electronic components from environmental factors.

Implementation Method 1

a patterned layer connected to the first major surface of the dielectric substrate by a laser bond

Methodology Applied
Scientific EffectLaser bonding: Laser Beam Welding

Implementation Method 2

The flange is welded to a welding portion of the patterned layer disposed between the flange and the first major surface of the dielectric substrate such that the ferrule is hermetically sealed to the dielectric substrate

Methodology Applied
Scientific EffectWelding: Welding

Data Source

PatentEP4065215B1Hermetic assembly and device including same
Publication Date: 2025.09.24 MEDTRONIC INC
  • EP4065215B1 patent drawingFigure 1~2
  • EP4065215B1 patent drawingFigure 3
  • EP4065215B1 patent drawingFigure 4

AI summary

Various embodiments of a hermetic assembly and a method of forming such assembly are disclosed. The hermetic assembly includes a dielectric substrate having a first major surface and a second major surface, a patterned layer connected to the first major surface of the dielectric substrate by a laser bond, and a ferrule having a body and a flange extending from the body. The flange is welded to a welding portion of the patterned layer that is disposed between the flange and the first major surface of the dielectric substrate such that the ferrule is hermetically sealed to the dielectric substrate.