Near-Infrared Curing of Flexible Electronic Coatings

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Solution Overview

Problem

Existing drying systems for electrical and electronic components are space-consuming, expensive, and inefficient, particularly for temperature-sensitive substrates like polymer films and paper, limiting the production of high-quality coatings with low thermal load and high throughput.

Innovation Solution

Utilize near-infrared radiation with adjustable power density and exposure duration to achieve sintering and crosslinking on temperature-sensitive substrates, combined with optional hot air drying, to control thermal load and maintain substrate integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional tunnel kiln-type drying systems are used, then drying and sintering can be achieved, but the systems are space-consuming and expensive to construct and operate

Engineering Contradiction:
Improvedrying qualityVSAvoidsystem size and cost
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces conventional thermal conduction-based tunnel kiln drying systems with a radiation-based drying system using infrared or microwave radiation sources. This substitution enables direct heating of the coating material without requiring large-scale thermal zones, thereby reducing system size and construction costs while maintaining effective drying and sintering capabilities

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the heating parameter from conventional thermal conduction to electromagnetic radiation (infrared or microwave). This parameter change allows for more concentrated and controllable energy delivery to the coating, achieving the same drying effect in a more compact system configuration

Inventive Principle:
Principle #35Parameter changes

2Productivity

If high energy density near-infrared radiation is applied, then sintering and crosslinking occur quickly with limited thermal load on substrate, but precise control of exposure time and power density is required

Engineering Contradiction:
Improvedrying speedVSAvoidcontrol system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent incorporates feedback control mechanisms that monitor the drying process parameters (such as substrate temperature, coating moisture content, or radiation intensity) and automatically adjust the radiation power density and exposure time. This feedback system enables precise control of the high-energy density radiation process, achieving rapid drying while preventing substrate damage through real-time parameter optimization

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent employs dynamic control of the radiation sources, allowing real-time adjustment of power density and exposure duration based on process conditions. This dynamic approach enables the system to deliver high energy density when needed for rapid sintering while reducing energy input when the coating approaches the desired state, thereby increasing productivity without compromising substrate integrity

Inventive Principle:
Principle #15Dynamics

3Manufacturing precision

If the substrate is heated to achieve sintering temperature, then coating sintering occurs, but temperature-sensitive substrates may be damaged

Engineering Contradiction:
Improvecoating sintering qualityVSAvoidsubstrate thermal damage
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by directing radiation energy specifically at the coating layer rather than uniformly heating the entire substrate-coating assembly. The radiation sources are positioned and configured to concentrate energy on the coating material, enabling sintering at the coating-substrate interface or within the coating itself while maintaining the substrate temperature below its damage threshold

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses the coating material itself as an intermediary that absorbs the near-infrared radiation and converts it to thermal energy locally. This intermediary mechanism allows the coating to reach sintering temperatures through direct radiation absorption while the substrate remains relatively cool, as the radiation energy is converted to heat within the coating layer before being conducted to the substrate

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

Achieves high-quality coatings with controlled thermal load, reducing energy consumption and system size while increasing throughput, suitable for various substrates including polymer films and metal foils.

Implementation Method 1

radiation in the near-infrared range has proven effective for this purpose, with a maximum amplitude in the wavelength range between 800 nm and 1,500 nm

Methodology Applied
Scientific EffectNear-infrared radiation: Infrared Radiation

Implementation Method 2

providing the energy required for sintering and/or crosslinking the starting material on the support... in such a way that its effect is exerted essentially within the coating, while the overall thermal load on the support remains as low as possible

Methodology Applied
Scientific EffectRadiative heating: Heating

Implementation Method 3

drying, sintering and/or crosslinking the starting material on the carrier

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP3977825B1Method and apparatus for producing electrical components on a flexible carrier
Publication Date: 2025.10.15 VALUE & INTPROP MANAGEMENT
  • EP3977825B1 patent drawingFigure 1~3

AI summary

The invention relates to a method for producing electrical or electronic components or circuits on a flexible, flat or three-dimensional substrate via the application of a liquid or paste-like starting material for a structured or unstructured electrical or electronic functional layer, and subsequent drying, sintering and/or curing of the starting material on the substrate, wherein the step of drying, sintering and/or curing involves a short surface-application of the coated substrate with radiation in the near-infrared range, with an amplitude maximum in a wavelength range between 800 and 1500 nm and with a power density on the surface of the substrate between 50 kW/m 2 and 1000 kW/m 2.