Graphene Film Transparent Heating Device with Resistance Gradient

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Solution Overview

Problem

Existing transparent heating devices using graphene face challenges in achieving uniform thermal emission across their surface, and integrating display capabilities while maintaining transparency and cost-effectiveness.

Innovation Solution

A transparent heating device is designed with a graphene film fixed to a substrate, featuring a resistance gradient achieved through varying thickness, absence, or density of graphene layers, and incorporating gate electrodes to adjust resistance, along with integrated light-emitting elements using the graphene film as an electrode.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a uniform graphene film is used for transparent heating, then the device is simple to manufacture, but the thermal emission is non-uniform with hotspots near electrodes

Engineering Contradiction:

Improvesimplicity of manufacturingVSAvoiduniformity of thermal emission

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies local quality by creating regions with different graphene layer configurations. Specifically, it uses a first region with fewer graphene layers (or openings) adjacent to electrodes to reduce local resistance and prevent hotspots, while using a second region with more complete graphene coverage in the center to optimize transparency and heating uniformity. This spatial variation in material properties resolves the contradiction between manufacturing simplicity and thermal emission uniformity.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent segments the graphene film into distinct regions with different properties. The heating element is divided into a first region (near electrodes) and a second region (central area), each with tailored graphene layer structures. This segmentation allows independent optimization of each region's electrical and thermal characteristics, achieving uniform thermal emission while maintaining manufacturing feasibility.

Inventive Principle:

Principle #1Segmentation

2Reliability

If ITO is used as the transparent conducting material, then the material provides good transparency and conductivity, but it is brittle and unsuitable for flexible surfaces

Engineering Contradiction:

Improvetransparency and conductivityVSAvoidflexibility

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent replaces the expensive and brittle ITO material with graphene, which is flexible and can be produced at lower cost. While graphene has different electrical properties, the invention compensates through the multi-layer configuration and regional variations, achieving both flexibility and functional performance. This material substitution directly addresses the contradiction between reliability (transparency/conductivity) and stability (flexibility).

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent creates a composite structure using multiple graphene layers (first and second layers) with different configurations. This composite approach allows optimization of both mechanical properties (flexibility) and electrical/optical properties (conductivity and transparency), resolving the contradiction inherent in using single-material systems like ITO.

Inventive Principle:

Principle #40Composite materials

3Power

If the graphene film has high conductivity, then the heating efficiency is improved, but the transparency is reduced

Engineering Contradiction:

Improveheating efficiencyVSAvoidtransparency

Core Design Contradiction:

PowerVSIllumination intensity

Solution Approach 1:

The patent resolves the conductivity-transparency trade-off by transitioning from a single-layer to a multi-layer configuration in the vertical dimension. By stacking multiple graphene layers with different coverage patterns and using regional variations, the system achieves enhanced electrical conductivity through parallel conduction paths while maintaining optical transparency through the cumulative thinness of the layers. This dimensional approach allows independent optimization of electrical and optical properties.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 provides improved uniform thermal emission and the ability to display information without compromising transparency, while being cost-effective and flexible, addressing the limitations of Indium tin oxide (ITO) and other materials.

Implementation Method 1

by applying a voltage to electrodes at the edges of the transparent element, the transparent element may be heated

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

there is a resistance gradient across the graphene film from the first electrode to the second electrode

Methodology Applied

Scientific EffectElectrical resistance: Electrical Resistance

Data Source

PatentUS10660159B2Transparent heating device with graphene film

Publication Date: 2020.05.19 CENT NAT DE LA RECH SCI (C N R S)

AI summary

The invention concerns a transparent heating device comprising: a graphene film fixed to a transparent substrate; a first electrode (205) connected to a first edge of the graphene film; and a second electrode (206) connected to a second edge of the graphene film, wherein there is a resistance gradient across the graphene film from the first electrode (205) to the second electrode (206).