Skin Conductivity Measurement Using Frequency Segmentation

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Solution Overview

Problem

Existing skin hydration and lipid measurement devices are inaccurate due to their reliance on conductivity measurements that are influenced by both water and lipid levels, leading to inconsistent results when measuring identical hydrated skin patches.

Innovation Solution

A system and method using at least two electrodes to generate electrical signals at specific frequencies, measuring conductivity, and determining water or lipid levels based on the frequency-dependent sensitivity to either water or lipid content, allowing for more accurate measurements by distinguishing between the two components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conductivity measurements are used to determine skin hydration levels, then the measurement process is simple, but the measurement precision deteriorates because conductivity depends on both water and lipid levels

Engineering Contradiction:
Improvemeasurement process simplicityVSAvoidhydration level measurement accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent segments the measurement process by using multiple frequency measurements to separately determine lipid content and water content. Instead of using a single conductivity measurement that conflates both components, the system performs distinct measurements at different frequencies to isolate and quantify each component independently, thereby resolving the interference between lipid and water effects on conductivity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the measurement parameter from a single conductivity value to multiple frequency-dependent conductivity values. By measuring skin impedance at different frequencies (typically low frequency for lipid content and high frequency for water content), the system transforms the single-parameter measurement into a multi-parameter measurement that can distinguish between lipid and water contributions to overall conductivity

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If single frequency conductivity measurements are used, then the device complexity is low, but the measurement precision deteriorates due to inability to distinguish water and lipid contributions

Engineering Contradiction:
Improvemeasurement system complexityVSAvoidcomponent level measurement accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent introduces dynamic measurement by varying the frequency of the applied electrical signal during measurement. Instead of using a fixed frequency, the system dynamically adjusts the frequency to match the characteristic response frequencies of different skin components (lipids at low frequency, water at high frequency), enabling selective measurement of each component's contribution to overall skin properties

Inventive Principle:
Principle #15Dynamics

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 enables more precise determination of skin hydration and lipid levels, reducing inaccuracies and providing a more reliable assessment of skin health and condition.

Implementation Method 1

measuring a conductivity between the at least two electrodes

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

determining a water or lipid level of skin based on the measured conductivity and the frequency of the electrical signal

Methodology Applied
Scientific EffectFrequency-dependent conductivity: Conduction (electrical)

Data Source

PatentEP3731738B1Determining a water and lipid level of skin
Publication Date: 2024.08.21 KONINKLIJKE PHILIPS NV
  • EP3731738B1 patent drawingFigure 1
  • EP3731738B1 patent drawingFigure 2~3
  • EP3731738B1 patent drawingFigure 4~5

AI summary

There is provided a system (100) and method for determining a water or lipid level of skin. The system (100) comprises at least two electrodes (108) suitable for contacting skin, and a signal generator (106) configured to generate an electrical signal at a frequency across the at least two electrodes (108). The system (100) is configured to measure a conductivity between the at least two electrodes (108). The system (100) is further configured to determine a water or lipid level of skin based on the measured conductivity and the frequency of the electrical signal.