Flexible Force Sensor Layers for Pressure and Shear Detection

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Solution Overview

Problem

There is a need for a force sensor that can be arranged on a flexible support without preventing flexing, capable of sensing both shear forces and pressure, and suitable for high-volume manufacturing.

Innovation Solution

A force sensing device comprising a flexible substrate with sensor units featuring a first electrode layer, a second electrode layer separated by an intermediate structure, trenches, bridging structures, and a rigid projecting structure embedded in elastic material, allowing decoupled detection of pressure and shear forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a force sensor is arranged on a flexible support, then the sensor can be integrated into flexible electronics, but the sensor may prevent flexing of the support

Engineering Contradiction:

Improveintegration into flexible electronicsVSAvoidflexing capability of support

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The force sensor is constructed with thin film layers including first and second electrodes deposited on flexible substrate, allowing the sensor structure itself to be flexible and conform to the support surface without preventing flexing

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The sensor is divided into multiple functional layers (first electrode layer, intermediate structure, second electrode layer) with each layer being thin and flexible, allowing the entire assembly to bend with the support while maintaining sensing capability

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If the sensor unit uses multiple electrode layers with intermediate structure, then the sensor can detect forces in multiple dimensions, but the device complexity increases

Engineering Contradiction:

Improvemulti-dimensional force detection capabilityVSAvoidsensor unit structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The intermediate structure serves multiple functions: it provides mechanical separation between electrode layers, enables force transmission in multiple directions, and maintains electrical isolation, allowing the sensor to detect both shear forces and pressure through a single integrated component

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The sensor detects forces in multiple dimensions by measuring changes in capacitance between electrode layers separated in the third dimension (vertical separation), enabling detection of both in-plane shear forces and out-of-plane pressure forces

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Stability of the object's composition

If trenches and bridging structures are added to the sensor unit, then the sensor can provide fixed relation between layers, but the manufacturing complexity increases

Engineering Contradiction:

Improvefixed relation between layersVSAvoidmanufacturing process

Core Design Contradiction:

Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

Trenches are formed in the intermediate structure before depositing the second electrode layer, and bridging structures are formed to connect trench walls, pre-establishing the mechanical anchors that will fix the relative position of layers during subsequent processing and operation

Inventive Principle:

Principle #10Preliminary action

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 device accurately senses forces in multiple dimensions, including shear and pressure, while maintaining flexibility and durability, facilitating high-volume manufacturing and three-dimensional force detection.

Implementation Method 1

an intermediate structure arranged between the first layer and the second layer, wherein the intermediate structure is configured to change characteristics of the force sensing device between the at least one first electrode and the at least one second electrode upon a force being received by the sensor unit

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

a rigid projecting structure arranged on the second layer projecting therefrom and connected to the at least one second electrode, wherein the rigid projecting structure is embedded in an elastic material for allowing the rigid projecting structure to be tilted in relation to the first layer upon receiving a force

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS20250271311A1Force sensing device and a method for manufacturing a force sensing device

Publication Date: 2025.08.28 INTERUNIVERSITAIR MICRO ELECTRONICS CENT (IMEC VZW)

AI summary

A force sensing device comprises: a flexible substrate; a sensor unit arranged thereon comprising: at least one first electrode in a first layer; at least one second electrode in a second layer; wherein a plurality of first electrodes and/or second electrodes is provided; an intermediate structure between the first and second electrodes for changing characteristics upon a force being received; trench(es) in the second layer partially surrounding the second electrode(s), wherein bridging structure(s) provides an anchoring position defining a fixed relation between the first and second layers; a rigid projecting structure projecting from the second layer and connected to the second electrode(s), wherein the rigid projecting structure is embedded in an elastic material for allowing the rigid projecting structure to be tilted in relation to the first layer.