Sheet-like Device with Segmented Film Layers for Flexible Wearables

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Solution Overview

Problem

Wearable electrical products, such as those incorporated into gloves, face challenges in achieving both robustness and flexibility, leading to poor wearing comfort and potential errors due to deformation-induced changes in capacitance from touch sensors.

Innovation Solution

A sheet-like device comprising a first film layer of thermoplastic resin and a second film layer of thermoplastic elastomer, with an electrical circuit layer bonded to the first film layer, allowing for enhanced flexibility and protection of conversion functions while reducing stress on the circuit layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electrical function is incorporated into glove, then functional performance is improved, but flexibility and wearing comfort deteriorate

Engineering Contradiction:

Improvefunctional performanceVSAvoidflexibility and wearing comfort

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The glove is divided into multiple regions with different film layer configurations. Regions with electrical circuits have both first and second film layers for protection, while regions without circuits have only the second film layer for maximum flexibility. This segmentation allows the glove to provide both functional performance and wearing comfort in different areas.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the glove have different structural characteristics. The first film layer is selectively positioned only where electrical circuits are present, providing localized protection where needed while maintaining flexibility in circuit-free areas. The second film layer extends across the entire glove surface for uniform flexibility.

Inventive Principle:

Principle #3Local quality

2Reliability

If touch sensor is incorporated in glove, then sensing function is improved, but measurement precision deteriorates due to deformation-induced capacitance changes

Engineering Contradiction:

Improvesensing functionVSAvoidcapacitance measurement accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The first film layer is positioned beforehand to cover and protect the touch sensor and electrical circuits in regions where deformation occurs. This protective layer cushions the sensor from direct mechanical stress and deformation, preventing deformation-induced capacitance changes before they can affect measurement accuracy.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Device complexity

If electrical circuit layer is directly formed on second film layer, then device complexity is reduced, but reliability deteriorates due to insufficient protection of conversion functions

Engineering Contradiction:

Improvestructure simplicityVSAvoidprotection of conversion functions

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The first film layer serves as an intermediary between the electrical circuit layer and the second film layer. It provides a protective interface that shields the conversion functions (touch sensor, heating element, light emitting element) from mechanical stress and deformation, while the second film layer provides additional flexibility and protection. This two-layer intermediary structure ensures reliable protection without excessive complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 sheet-like device improves robustness, flexibility, and operation stability, enhancing wearing comfort by allowing for greater elongation and accurate positioning of conversion units, while preventing damage from stress and deformation.

Implementation Method 1

The second film layer contains a thermoplastic elastomer that extends more than the thermoplastic resin as a main material. The second film layer has an elongation per unit length greater than an elongation per unit length of the first film layer, at 20° C.

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

The second film layer has an elongation per unit length greater than an elongation per unit length of the first film layer, at 20° C.

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 3

The first film layer contains a thermoplastic resin as a main material. The second film layer contains a thermoplastic elastomer that extends more than the thermoplastic resin as a main material.

Methodology Applied

Scientific EffectThermoplastic deformation: Phase Change

Data Source

PatentUS11683885B2Sheet-like device and manufacturing method of the same

Publication Date: 2023.06.20 NISSHA PRINTING CO LTD

AI summary

Provided is a sheet-like device suitable for a flexible electrical product that is robust, highly flexible, and operates stably. The sheet-like device includes a first part where a first film layer, a first conversion unit, and a second film layer overlap, a second part where the first film layer is absent and the second film layer is present, and a third part where the first film layer, a second conversion unit, and the second film layer overlap. The first part the second part, and the third part are arranged side by side in this order in a first direction. A first region including the first part the second part, and the third part has an elongation per unit length greater than an elongation per unit length of the first film layer alone when a same force is applied in the first direction at 20° C.