Stick-on Biosensor Adhesive Rigidity and Skin Conformability

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Biosensors face issues with electrode detachment and signal noise when the skin is crinkled during measurement, leading to unsatisfactory acquisition of biological information.

Innovation Solution

A stick-on biosensor design featuring a pressure-sensitive adhesive layer with a flexural rigidity of 0.010 MPa·mm^3/mm or higher and adhesive strength between 0.6 N/cm^2 and 5.0 N/cm^2, ensuring secure attachment and stable signal acquisition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the biosensor uses a conventional plate-like polymer structure, then the structural integrity is maintained, but the electrode peels off from the living body when skin is crinkled

Engineering Contradiction:
Improveelectrode attachment stabilityVSAvoidadhesive strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent optimizes the flexural rigidity parameter of the pressure-sensitive adhesive layer to be within the specific range of 0.001 to 0.05 MPa·m², which resolves the contradiction between maintaining structural integrity and preventing electrode peeling. This parameter optimization allows the adhesive layer to be flexible enough to conform to crinkled skin while maintaining sufficient adhesive strength.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite structure consisting of a pressure-sensitive adhesive layer combined with a base material layer. This composite material approach enables the biosensor to achieve both the required flexibility for skin conformability and the necessary mechanical strength for reliable electrode attachment, resolving the contradiction between these two requirements.

Inventive Principle:
Principle #40Composite materials

2Reliability

If the biosensor uses a rigid structure, then the structural stability is maintained, but gaps are produced between the sensor and crinkled skin

Engineering Contradiction:
Improvesignal acquisition qualityVSAvoidstructural stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent changes the flexural rigidity parameter from a high value (rigid structure) to a low value within the range of 0.001 to 0.05 MPa·m². This parameter change enables the biosensor to conform to crinkled skin surfaces, eliminating gaps and improving signal acquisition quality while maintaining adequate structural stability through the composite layer design.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the adhesive strength is increased to prevent peeling, then the electrode attachment is improved, but the biosensor cannot conform to crinkled skin

Engineering Contradiction:
Improveelectrode attachment stabilityVSAvoidskin conformability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent optimizes the flexural rigidity parameter to a low range (0.001 to 0.05 MPa·m²), which enables the adhesive layer to conform to crinkled skin while maintaining sufficient adhesive strength. This parameter optimization resolves the contradiction by allowing the material to be both flexible and adhesive simultaneously.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The composite structure of the pressure-sensitive adhesive layer and base material layer provides a solution where the adhesive layer offers flexibility and conformability, while the base material provides structural support. This composite approach enables both skin conformability and reliable electrode attachment.

Inventive Principle:
Principle #40Composite materials

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 biosensor maintains secure attachment and reduces noise, enabling the acquisition of satisfactory biological information even with skin movement, by optimizing flexural rigidity and adhesive strength.

Implementation Method 1

a pressure-sensitive adhesive layer with a flexural rigidity of 0.010 MPa·mm^3/mm or higher and adhesive strength between 0.6 N/cm^2 and 5.0 N/cm^2, ensuring secure attachment

Methodology Applied
Scientific EffectAdhesive: Adhesive

Data Source

PatentEP3949846B1Stick-on biosensor
Publication Date: 2023.11.22 NITTO DENKO CORP
  • EP3949846B1 patent drawingFigure 1
  • EP3949846B1 patent drawingFigure 2
  • EP3949846B1 patent drawingFigure 3

AI summary

A stick-on biosensor capable of acquiring satisfactory biological information is provided. The stick-on biosensor includes a pressure-sensitive adhesive layer and an electrode part, said pressure-sensitive adhesive layer having a stick-on surface to be attached to a subject; a base material layer provided on the side opposite the stick-on surface of the pressure-sensitive adhesive layer; and an electronic device provided on the base material layer and configured to process a biological signal acquired through the electrode part. A structure, which includes the pressure-sensitive adhesive layer, the electrode part, and the base material layer, has a flexural rigidity of 0.010 [MPa·mm3/mm] or higher, and an adhesive strength of the electrode part to adhere to the subject is greater than 0.6 [N/cm2] and less than or equal to 5.0 [N/cm2].