Implantable Optical Sensor Window Masking for Reflection Noise

Solution Overview

Problem

Existing implantable medical devices (IMDs) face challenges in accurately sensing physiological characteristics due to interference from internally reflected light and ambient light, which reduces the effectiveness of optical sensing.

Innovation Solution

The implementation of masking, integrated lens, underfill, and backfill at specific locations within the IMD to reduce internally reflected light and ambient light interference, thereby improving the percentage of optical sensing light detected by the sensor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If optical sensing is performed in implantable medical devices, then physiological characteristics can be measured, but internally reflected light and ambient light interfere with the sensing accuracy

Engineering Contradiction:

Improvephysiological characteristic measurement accuracyVSAvoidlight reflection and ambient light interference

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and removes the harmful reflected light from the optical path by positioning the light source at an angle and using a mask to block the reflected light pathway, allowing only the useful transmitted light to reach the detector

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a mask as an intermediary element between the light source and detector that selectively blocks harmful reflected light while allowing useful light to pass through, improving signal quality without requiring fundamental changes to the optical sensor architecture

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If light source emits light through optical window, then optical sensing can detect tissue interactions, but internally reflected light reduces the percentage of useful light detected

Engineering Contradiction:

Improvepercentage of optical sensing light detectedVSAvoidlight energy lost to internal reflection

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The patent applies local quality by positioning the light source at a specific angle relative to the optical window and using a mask at a specific location to block reflected light only in the harmful direction while preserving light transmission in the useful direction

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent converts the harmful internal reflection phenomenon into a beneficial directional control mechanism by strategically positioning the light source and mask to exploit the reflection geometry to block harmful light pathways while allowing useful light to pass through

Inventive Principle:

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

3Reliability

If optical sensor detects light, then physiological signals can be measured, but ambient light and internal reflections create noise that reduces measurement accuracy

Engineering Contradiction:

Improveoptical sensing reliabilityVSAvoidnoise from reflected and ambient light

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts and removes the harmful reflected light from the optical path by positioning the light source at an angle and using a mask to block the reflected light pathway, allowing only the useful transmitted light to reach the detector

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a mask as an intermediary element between the light source and detector that selectively blocks harmful reflected light while allowing useful light to pass through, improving signal quality without requiring fundamental changes to the optical sensor architecture

Inventive Principle:

Principle #24Intermediary (Mediator)

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 approach enhances the accuracy of physiological characteristic determination by improving the percentage of optical sensing light detected, leading to more precise measurements.

Implementation Method 1

a masking on a portion of the optical window, the masking configured to absorb a portion of the emitted light internally reflected within the optical window

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

light that is emitted by a light source of an optical sensor that passes into tissue and interacts with tissue, such as through absorption and scattering

Methodology Applied

Scientific EffectLight detection: Photoelectric Effect

Data Source

PatentUS20260026720A1Implantable medical device configured for optical sensing

Publication Date: 2026.01.29 MEDTRONIC INC

AI summary

An example implantable medical device includes a housing comprising an optical window; an optical sensor within the housing and configured to emit light to the optical window; and a masking on a portion of the optical window, the masking configured to absorb a portion of the emitted light internally reflected within the optical window.