Movable Optical Unit for Simultaneous ECG and PPG Sensor

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing physiological measurement devices face limitations in measurement quality and ergonomics, particularly when designed for large-scale production and not just as prototypes.

Innovation Solution

A set of physiological measurement sensors is developed, featuring an electrode with a contact surface and an optical unit that is movable relative to the electrode, incorporating a force sensor to determine the force exerted on the optical unit, thereby enhancing simultaneous ECG and PPG measurement quality and ergonomics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the optical unit is made movable relative to the electrode contact surface, then measurement quality and ergonomics are improved, but device complexity increases

Engineering Contradiction:
Improvemeasurement qualityVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The optical unit is designed to be movable relative to the electrode contact surface, transitioning between a first position for ECG measurement and a second position for PPG measurement. This dynamic repositioning allows the same sensor assembly to perform multiple measurement functions with optimized contact geometry for each specific measurement type, thereby improving measurement quality without requiring separate sensor assemblies.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If the optical unit protrudes from the contact surface, then ergonomics and finger guidance are improved, but manufacturing precision requirements increase

Engineering Contradiction:
ImproveergonomicsVSAvoidmanufacturing precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The optical unit is designed to protrude from the electrode contact surface by a predetermined amount (0.1mm to 2mm), creating a physical guide that preliminarily directs the user's finger to the correct measurement location. This protrusion acts as a built-in ergonomic guide that ensures proper finger placement before the measurement begins, improving ease of operation while the protrusion depth is controlled within specific manufacturing tolerances.

Inventive Principle:
Principle #10Preliminary action

3Stability of the object's composition

If the contact surface completely surrounds the optical unit, then measurement stability is improved, but the aperture size for optical access is reduced

Engineering Contradiction:
Improvemeasurement stabilityVSAvoidaperture size
Core Design Contradiction:
Stability of the object's compositionVSArea of stationary object

Solution Approach 1:

The sensor assembly is segmented into distinct functional zones: the electrode contact surface that surrounds the optical unit for stable electrical contact, and the optical unit itself that protrudes to provide optical access. This segmentation allows the contact surface to maintain complete surrounding coverage for stability while the optical unit's protrusion creates its own aperture for light transmission, resolving the conflict between stability and optical access.

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

The solution improves the quality and ergonomics of simultaneous ECG and PPG measurements, facilitating easier production and distribution on a large scale while maintaining effective measurement capabilities.

Implementation Method 1

an optical sensor, in particular to determine a heart rate or a blood oxygen saturation of the user

Methodology Applied
Scientific EffectOptical transmission: Light

Implementation Method 2

a force sensor configured to determine information relating to the force exerted on the optical unit in the displaced position

Methodology Applied
Scientific EffectForce measurement: Force

Implementation Method 3

an electrode comprising a contact surface configured to be in contact with a user

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP4566525A1Sensor arrangement with an optical unit movable in an electrode
Publication Date: 2025.06.11 WITHINGS SAS
  • EP4566525A1 patent drawingFigure 1
  • EP4566525A1 patent drawingFigure 2
  • EP4566525A1 patent drawingFigure 3

AI summary

A set of physiological measurement sensors comprising: - an electrode (110L) comprising a contact surface (402) configured to be in contact with a user, - an optical unit (116L) movable relative to the contact surface (402) of the electrode (116L) between a rest position and a displaced position, the optical unit comprising: ∘ an interaction surface (604) configured to be in contact with a user, the interaction surface (604) being adjacent to the contact surface (402), ∘ an optical sensor, - a force sensor (502) configured to determine information relating to the force exerted on the optical unit (116L) in the displaced position.