Multi-section Finger Sleeve Probe for Stable SpO2 Monitoring

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing finger sleeve-type SpO2 probes are prone to dropping off due to inadequate frictional resistance, uneven pressure distribution, and discomfort during use, especially when used for long-term monitoring like sleep respiration, as they do not accurately match the segmented structure of fingers and can cause blood flow issues.

Innovation Solution

A multi-section finger sleeve-type probe with a cylindrical design featuring a flexible flat cable and light-emitting and photo-diodes positioned on the finger back and pulp, respectively, providing increased frictional resistance and allowing for better fitting around the finger's shape, with separate sections for the first and second knuckles to enhance stability and comfort.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the finger sleeve is designed to be flat and narrow with large gaps on both sides to adapt to different finger shapes, then the probe can be worn by patients without needing many sizes, but the frictional resistance is small and the probe is easy to drop off

Engineering Contradiction:
Improveadaptability to different finger shapesVSAvoidstability of probe on finger
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The finger sleeve is divided into multiple sections (first section, second section, third section) with different wall thicknesses. The first section has greater wall thickness for enhanced grip, while the second and third sections have smaller wall thicknesses for comfort and adaptability. This segmentation allows the probe to maintain stability through the thick first section while adapting to different finger shapes through the thinner subsequent sections.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the finger sleeve is designed to be relatively thick or made of hard material to increase grip force, then the probe is not easy to drop off, but the pressure on the finger is big and causes discomfort

Engineering Contradiction:
Improvegrip force of probeVSAvoidpressure on finger
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Different sections of the finger sleeve have different wall thicknesses tailored to specific functional requirements. The first section has greater wall thickness to provide sufficient grip force and prevent dropping, while the second and third sections have smaller wall thicknesses to reduce pressure and improve comfort. This local differentiation of quality allows the probe to maintain reliability where needed while minimizing harmful pressure elsewhere.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If the flat shape is used to accommodate wiring pipes on both left and right sides, then the wiring can be distributed, but the thickening ridge oppresses the fingers and causes discomfort

Engineering Contradiction:
Improvewiring distributionVSAvoidoppression of fingers
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The wiring structure is moved from a two-dimensional distribution on both left and right sides to a one-dimensional arrangement concentrated on the front side of the finger sleeve. This dimensional change eliminates the need for thickening ridges on both sides, thereby removing the oppressive effect on fingers while still accommodating the wiring pipes effectively through the front-side concentration.

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

4Device complexity

If the single section structure is used to simplify design, then the manufacturing is easier, but it is difficult to identify the two sections of finger involved and pressure distribution is uneven

Engineering Contradiction:
Improvestructural complexityVSAvoidpressure distribution accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The finger sleeve is segmented into multiple sections (first, second, and third sections) with distinct wall thicknesses. The first section has greater wall thickness for grip, while the second and third sections have smaller wall thicknesses. This segmentation not only reflects the actual segmented structure of fingers (including the knuckle region) but also enables accurate pressure distribution matching different finger regions, improving manufacturing precision despite increased structural complexity.

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 multi-section design stabilizes the probe on the finger, reduces the likelihood of it dropping off, and allows for comfortable long-term use by distributing pressure evenly and accommodating finger movement, improving measurement reliability.

Implementation Method 1

a light emitting diode and a photo diode are respectively in contact with the nail and the finger pulp. The light emitted by the light emitting diode passes through the nail and is received by the photo diode on the finger pulp side

Methodology Applied
Scientific EffectLight emitting diode: Light Emitting Diode

Implementation Method 2

a SpO2 measuring instrument (known as pulse oximeter) using the photoelectric principle is generally used for measurement

Methodology Applied
Scientific EffectPhotoelectric principle: Photoelectric Effect

Data Source

PatentEP3443903B1Multi-section finger sleeve-type probe
Publication Date: 2021.11.17 PAN WEIJIANG
  • EP3443903B1 patent drawingFigure 1~2
  • EP3443903B1 patent drawingFigure 3~4
  • EP3443903B1 patent drawingFigure 5~6

AI summary

The present invention provides a multi-section finger sleeve-type probe, which comprises a finger sleeve body, a flexible flat cable mounted on the finger sleeve body, a light emitting diode, a photo diode, and a wire electrically connected to the flexible flat cable. The finger sleeve body is a cylinder with an opening at the bottom thereof. Comparing with an existing finger sleeve-type probe in which wiring pipes are provided on both the left and right sides of a silicone sleeve and thus the silicone sleeve is flattened, the finger sleeve body fits the shape of a finger and fully wraps around the finger. While being used, the finger is inserted into the finger sleeve body and expands the periphery thereof, thus the finger is totally wrapped to provide a big resistance. The multi-section finger sleeve-type probe can be worn stably, be not easy to drop off, and be suitable for long term use. Also, the finger sleeve body from top to bottom comprises a first knuckle sleeve and a second knuckle sleeve respectively corresponding to the distal knuckle and the medial knuckle of the finger, thus allowing the two knuckles of the finger to be fixed, thereby further increasing the stability of the finger sleeve-type probe when worn.