Bioelectrode Protrusions for Scalp Contact in Dense Hair

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Solution Overview

Problem

Conventional biological electrodes with increased protrusions for electroencephalography struggle to maintain stable contact with the scalp, especially in subjects with dense hair, requiring excessive pressing that can cause discomfort.

Innovation Solution

A biological electrode design featuring electrode protrusions with a height of 6 to 15mm, arranged on the outer peripheral part of the electrode body, creating a central space to accommodate hair and ensuring stable contact without excessive pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the number of protrusions is increased to increase contact area with the scalp, then the contact area is improved, but the space for housing hair is reduced causing the electrode to float

Engineering Contradiction:
Improvecontact areaVSAvoidcontact stability
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The electrode surface is segmented into multiple protrusions that are distributed across the electrode body. Each protrusion makes contact with the scalp at different locations, while the spaces between protrusions accommodate hair. This segmentation allows the electrode to maintain contact stability without requiring excessive pressing force, even in subjects with dense hair.

Inventive Principle:
Principle #1Segmentation

2Reliability

If strong pressing force is applied to prevent floating and ensure contact, then contact stability is improved, but scalp discomfort increases

Engineering Contradiction:
Improvecontact stabilityVSAvoidscalp discomfort
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The electrode applies pressing force locally at multiple discrete protrusion points rather than distributing force uniformly across the entire electrode surface. This localized pressing approach ensures stable contact at each protrusion while minimizing overall pressure on the scalp, thereby reducing discomfort for the subject.

Inventive Principle:
Principle #3Local quality

3Area of stationary object

If protrusions are densely arranged to maximize contact area, then contact area is improved, but the space for hair accommodation is reduced

Engineering Contradiction:
Improvecontact areaVSAvoidadaptability to hair volume
Core Design Contradiction:
Area of stationary objectVSAdaptability or versatility

Solution Approach 1:

The protrusions are arranged in a three-dimensional configuration with varying heights and spatial distributions. This dimensional arrangement creates vertical and horizontal spaces between protrusions that can accommodate hair of different volumes and densities, allowing the electrode to adapt to subjects with varying hair characteristics while maintaining scalp contact.

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

Data Source

PatentEP4295770B1bioelectrode
Publication Date: 2026.03.04 NOK CORP
  • EP4295770B1 patent drawingFigure 1~2
  • EP4295770B1 patent drawingFigure 3~4

AI summary

There is provided a biological electrode capable of realizing good contacting with a scalp of a subject for detection. The biological electrode includes an electrode member 20 in contact with a body of the subject, wherein the electrode member 20 has an electrode body 21 having a plate shape and a plurality of electrode protrusions 22 provided so as to protrude from the electrode protrusion forming surface 21b of the electrode body 21, and the plurality of electrode protrusions 22 are arranged on an outer peripheral part 29 of the electrode protrution forming surface 21b so as to avoid a central part 28 of the electrode protrusion forming surface 21b of the electrode body 21, and a protrusion height h of each electrode protrusion 22 from a proximal end thereof to a distal end thereof in a direction perpendicular to the electrode protrusion forming surface 21b is 6 to 15mm.