Hermetically-Sealed Package for Implantable Optical Sensors

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Solution Overview

Problem

Existing implantable medical devices (IMDs) face challenges in providing reliable, cost-effective, and compact optical sensors for remote monitoring of physiological conditions due to high costs, large size, and complex component requirements, which are difficult to manage effectively in chronically implantable settings.

Innovation Solution

A hermetically-sealed package is developed, comprising a housing and a non-conductive transparent substrate laser-bonded to the housing, with a light source and detector on the substrate to emit and detect light scattered by tissue, enabling low-cost, low-power subcutaneous optical sensing and remote monitoring of physiological conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional optical sensors are used in implantable medical devices, then reliable physiological monitoring is achieved, but device size and cost increase significantly

Engineering Contradiction:
Improvephysiological monitoring reliabilityVSAvoiddevice size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent combines the light source, detector, and optical window into a single integrated substrate structure. The substrate serves multiple functions simultaneously: it supports the light source and detector, provides an optical path for light transmission, and acts as a hermetic seal when bonded to the housing. This integration eliminates the need for separate components and reduces overall device volume while maintaining monitoring reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The substrate is designed to perform multiple functions: it serves as a mechanical support structure for the light source and detector, as an optical transmission medium for light propagation, and as a hermetic barrier when laser-bonded to the housing. This multi-functionality reduces the number of components needed and decreases device size while maintaining reliable physiological monitoring capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If traditional optical sensors are used in implantable medical devices, then reliable physiological monitoring is achieved, but manufacturing cost increases

Engineering Contradiction:
Improvephysiological monitoring reliabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The integration of light source, detector, and optical window onto a single substrate reduces the number of discrete components that need to be handled, aligned, and assembled. This simplification of the assembly process reduces manufacturing complexity and cost while maintaining the reliable physiological monitoring function through the integrated optical pathway.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces traditional mechanical sealing methods with laser bonding to hermetically seal the substrate to the housing. Laser bonding provides a more precise, automated, and reliable sealing process that reduces manual intervention and improves manufacturing efficiency, thereby reducing cost while ensuring the integrity needed for reliable monitoring.

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

3Reliability

If hermetic sealing is implemented to protect internal components, then environmental stability is improved, but manufacturing complexity increases

Engineering Contradiction:
Improveenvironmental stabilityVSAvoidsealing structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The substrate is designed to serve as both the optical component holder and the hermetic seal. By bonding the substrate directly to the housing with laser bonding, the sealing function is integrated into the existing structural component rather than requiring a separate sealing mechanism. This reduces sealing structure complexity while maintaining environmental stability for reliable operation.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces complex mechanical sealing structures with laser bonding technology. Laser bonding creates a hermetic seal through direct material fusion, eliminating the need for gaskets, O-rings, or multiple sealing layers. This simplifies the sealing structure while providing robust environmental protection for the internal optical components.

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

4Volume of moving object

If compact device design is implemented, then implantability is improved, but component integration difficulty increases

Engineering Contradiction:
Improvedevice sizeVSAvoidcomponent integration difficulty
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The light source, detector, and optical window are merged into a single substrate assembly, which dramatically reduces device volume and improves implantability. The integrated design eliminates the need for precise alignment of multiple separate components during assembly, as all optical elements are pre-positioned on the substrate. This reduces component integration difficulty while achieving compact dimensions suitable for implantation.

Inventive Principle:
Principle #5Merging (Combining)

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 provides earlier detection of worsening conditions before symptoms appear, enabling remote monitoring of physiological conditions like arterial oxygen levels with reduced size and cost compared to traditional methods, facilitating more efficient patient management.

Implementation Method 1

a non-conductive substrate hermetically sealed to the housing by a laser bond

Methodology Applied
Scientific EffectLaser bonding: Laser Beam Welding

Data Source

PatentEP3606606B1Hermetically-sealed package
Publication Date: 2023.10.18 MEDTRONIC INC
  • EP3606606B1 patent drawingFigure 1~2
  • EP3606606B1 patent drawingFigure 3~5
  • EP3606606B1 patent drawingFigure 6

AI summary

Various embodiments of a hermetically-sealed package and a method of forming such package are disclosed. The package can include a housing having an inner surface and an outer surface, and a non-conductive substrate hermetically sealed to the housing. The package can also include a light source disposed on a first major surface of the substrate and adapted to emit light through the first and second major surfaces of the substrate, and a detector disposed on the first major surface of the substrate and adapted to detect the light emitted by the light source.