Electrostatic Sensor Deformable Layer Design for Bending Stress

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Solution Overview

Problem

Electrostatic-capacity-type pressure sensors with multiple layers can experience separation between layers when bent, due to compressive and tensile stresses, which can lead to malfunction when worn on a subject body.

Innovation Solution

Incorporating a deformable layer between the sensor electrode layer and the reference electrode layer, which is recessed or discontinuous between sensing units, and a shaped portion on the reference electrode layer to reduce shear stress and prevent layer separation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple layers are laminated to form the pressure sensor, then the sensor can be made functional with sensing capabilities, but separation occurs between layers when bent due to compressive and tensile stresses

Engineering Contradiction:

Improvelayer adhesionVSAvoidinterlayer bond strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The deformable layer is designed with different properties in different regions: it is recessed or discontinuous between sensing units to reduce shear stress, while maintaining continuity over sensing units to enable pressure detection. This local differentiation allows the layer to accommodate bending stresses without separating

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The deformable layer's physical configuration is changed by making it recessed or discontinuous in specific areas, altering its mechanical properties locally to reduce shear stress concentration between layers during bending, thereby preventing separation

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the deformable layer is made continuous to maintain structural integrity, then layer separation is prevented, but sensitivity of the sensing units is reduced

Engineering Contradiction:

Improvelayer stabilityVSAvoidpressure sensing accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The deformable layer exhibits local quality variations: it is continuous over sensing units to maintain structural support while allowing deformation for pressure detection, and recessed or discontinuous between sensing units to minimize interference with pressure sensitivity in those regions

Inventive Principle:

Principle #3Local quality

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 solution effectively suppresses separation between layers, enhancing the sensor's flexibility and durability while maintaining high sensitivity and accuracy.

Implementation Method 1

a deformable layer disposed between the reference electrode layer and the sensor electrode layer, the deformable layer being to deform elastically due to application of pressure

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentUS11536619B2Sensor, band, electronic device, and wristwatch-type electronic device

Publication Date: 2022.12.27 SONY GROUP CORP

AI summary

A sensor includes: an electrostatic-capacity-type sensor electrode layer having a plurality of sensing units; a reference electrode layer opposed to one main face of the sensor electrode layer; and a deformable layer disposed between the reference electrode layer and the sensor electrode layer, the deformable layer being to deform elastically due to application of pressure. The deformable layer is recessed between the sensing units or discontinuous between the sensing units. The reference electrode layer has a shaped portion between the sensing units.