Finger Probe Side-Positioning for Nail Polish Interference

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Solution Overview

Problem

Existing finger probes used to calculate physiological parameters, such as pulsation and arterial oxygen saturation, face challenges when nail polish or nail art is present, as it can absorb light beams, leading to inaccurate readings and potential delays in emergency situations, especially since removing such decorations is inconvenient and may not be feasible.

Innovation Solution

The probe is designed with a configuration where the light emitter and detector are positioned on the side faces of the finger, avoiding the nail area, and are continuously extended to the pad side, which suppresses ambient light entry, ensuring accurate calculations regardless of nail polish or nail art presence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the light emitter and detector are positioned on the fingertip to measure physiological parameters, then the measurement function is achieved, but the nail polish or nail art absorbs light causing measurement inaccuracy

Engineering Contradiction:
Improvephysiological parameter measurement accuracyVSAvoidlight absorption by nail polish
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent transitions the measurement location from the fingertip surface (2D plane) to the side face of the finger (different spatial dimension), positioning the light emitter and detector to illuminate and detect light through the lateral aspect of the finger rather than through the nail. This dimensional shift eliminates interference from nail polish while maintaining physiological parameter measurement capability.

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

2Measurement precision

If the light emitter and detector are positioned on the side face of the finger to avoid nail interference, then measurement accuracy is improved, but ambient light may enter and affect detection

Engineering Contradiction:
Improvephysiological parameter measurement accuracyVSAvoidambient light interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a light shield as an intermediary element positioned between the ambient light source and the light detector. This shield acts as a mediator that selectively blocks harmful ambient light while allowing the measurement function to proceed, thereby resolving the contradiction between avoiding nail interference and preventing light contamination.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If the probe structure is extended to continuously connect the nail-side holding face and pad-side holding face, then ambient light suppression is improved, but the device complexity increases

Engineering Contradiction:
Improveambient light suppressionVSAvoidprobe structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the nail-side holding face and pad-side holding face into a continuous, integrated structure. This consolidation creates an unbroken light-shielding barrier that effectively blocks ambient light while simplifying the overall probe design by eliminating the need for separate components or complex assembly mechanisms.

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

This configuration allows for stable and accurate calculation of physiological parameters by positioning the light emitter and detector on the side faces of the finger, avoiding nail interference and ambient light, thus maintaining calculation accuracy without the need to remove nail polish or nail art.

Implementation Method 1

a light beam that is emitted from the light-emitting element, and that is transmitted through the living tissue of the fingertip

Methodology Applied
Scientific EffectLight transmission through tissue: Light

Implementation Method 2

The light beam emitted from the light-emitting element is determined to have a wavelength at which a light beam is to be absorbed by a material in blood

Methodology Applied
Scientific EffectLight absorption by blood: Absorption (EM radiation)

Implementation Method 3

the light beam emitted from the light-emitting element may be absorbed by coloring matter of the nail polish or the nail art

Methodology Applied
Scientific EffectLight absorption by coloring matter: Absorption (EM radiation)

Data Source

PatentEP3117763B1probe
Publication Date: 2022.06.22 NIHON KOHDEN CORP
  • EP3117763B1 patent drawingFigure 1A~1B
  • EP3117763B1 patent drawingFigure 2A~2B

AI summary

A probe which is to be attached to a finger of a subject to acquire physiological parameter of the subject includes a light emitter that emits a light beam toward the finger, a light detector that outputs a signal corresponding to a light beam that is transmitted through or reflected from the finger, a first holding face that has a portion which is faced with a nail of the finger and another portion which is faced with a side face of the finger, and a second holding face that has a portion which is faced with a pad of the finger and another portion which is faced with the side face of the finger. In a state where the probe is attached to the finger, the first holding face and the second holding face are placed to be continuous to each other.