Flexible Substrate Electronic Devices for Curved Surface Conformal Contact

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing physiological measurement and stimulation technologies face challenges in creating high-fidelity, robust, and reliable electronics that can conform to complex and curved surfaces, such as those found on moving body parts, due to difficulties in establishing long-lasting electrical contacts and achieving comfortable, integrated systems.

Innovation Solution

Development of ultrathin, flexible, and stretchable electronics with a substrate that can conform to curved surfaces, incorporating sensors and actuators with inorganic semiconductor and metallic components, allowing for conformal contact and flexible integration on various shapes, including those that change over time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional bulk electrodes mounted on adhesive tapes or mechanical clamps are used, then electrical contacts can be established, but the system causes skin irritation and discomfort during prolonged use

Engineering Contradiction:
Improveelectrical contact reliabilityVSAvoidskin irritation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent employs thin-film flexible substrates (e.g., polyimide, PDMS) as the base for electrode arrays, replacing traditional bulk electrodes and adhesive tapes. This allows the electrode array to conform to curved skin surfaces while maintaining electrical contact, reducing skin irritation through flexible, biocompatible materials that accommodate skin movement and morphology.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The electrode array is segmented into multiple small electrodes arranged in arrays on flexible substrates, rather than using few large bulk electrodes. This segmentation allows better distribution of contact pressure, improved conformability to skin surfaces, and reduced irritation while maintaining reliable electrical contacts for physiological measurements.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If rigid circuit boards and separate terminal connections are used, then system capabilities can be achieved, but the overall size and weight cause discomfort during prolonged use

Engineering Contradiction:
Improvesystem capabilityVSAvoiddevice weight
Core Design Contradiction:
Adaptability or versatilityVSWeight of moving object

Solution Approach 1:

The patent integrates sensors, signal processing circuits, power management, and communication components into a single flexible wearable device. The rigid circuit boards and separate terminal connections are replaced with flexible printed circuits and integrated circuits on the same flexible substrate, merging multiple functional components into one lightweight unit that maintains full system capability while dramatically reducing weight and size.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent transitions from three-dimensional rigid box structures housing separate components to two-dimensional flexible planar integration. Electronic components are arranged in layered configurations on flexible substrates, enabling integration of multiple functions in a thin, lightweight form factor that conforms to the body rather than adding bulk.

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

3Measurement precision

If traditional electrode arrays are used, then basic sensing can be performed, but high-fidelity measurements on complex curved surfaces cannot be achieved

Engineering Contradiction:
Improvephysiological measurement fidelityVSAvoidsurface conformability
Core Design Contradiction:
Measurement precisionVSShape

Solution Approach 1:

The patent uses flexible thin-film substrates for electrode arrays that can conform to complex curved surfaces such as fingers, hands, and other body parts. The flexibility and thinness of the substrate enable intimate contact with irregular surfaces, ensuring high-fidelity physiological measurements by maintaining consistent electrical contact across the entire measurement area.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent employs densely packed arrays of small electrodes on flexible substrates, providing high spatial resolution for capturing physiological signals on curved surfaces. The segmented electrode configuration allows precise localization of signals and adapts to complex surface geometries, achieving measurement fidelity that cannot be obtained with traditional sparse electrode placements.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2830492B1Appendage mountable electronic devices conformable to surfaces and method of making the same
Publication Date: 2021.05.19 THE BOARD OF TRUSTEES OF THE UNIV OF ILLINOIS
  • EP2830492B1 patent drawingFigure 1(a)~1(d)
  • EP2830492B1 patent drawingFigure 2(a)~2(d)
  • EP2830492B1 patent drawingFigure 3(a)~3(f)

AI summary

Disclosed are appendage mountable electronic systems and related methods for covering and conforming to an appendage surface. A flexible or stretchable substrate has an inner surface for receiving an appendage, including an appendage having a curved surface, and an opposed outer surface that is accessible to external surfaces. A stretchable or flexible electronic device is supported by the substrate inner and/or outer surface, depending on the application of interest. The electronic device in combination with the substrate provides a net bending stiffness to facilitate conformal contact between the inner surface and a surface of the appendage provided within the enclosure. In an aspect, the system is capable of surface flipping without adversely impacting electronic device functionality, such as electronic devices comprising arrays of sensors, actuators, or both sensors and actuators.