Patterned Structure Roll Coating for Uniform Peak Coverage

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Solution Overview

Problem

Existing roll coating systems struggle to achieve controlled coating coverage and uniformity on patterned substrate surfaces, particularly when dealing with three-dimensional structures, leading to flooding and non-uniform application.

Innovation Solution

A deformable coating roll with a softer inner layer and a harder outer layer is used, combined with a metering mechanism, to conformally coat the peaks of a patterned surface while avoiding troughs, providing better control over coating thickness and uniformity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a conventional rigid coating roll is used, then the coating system is simple and easy to operate, but the coating coverage and uniformity on patterned surfaces cannot be controlled

Engineering Contradiction:
Improvecoating uniformityVSAvoidcoating roll structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The coating roll is divided into two distinct layers: a deformable inner layer and a deformable outer layer, each serving different functions. The inner layer provides conformability to the patterned substrate surface, while the outer layer provides the necessary surface hardness and coating transfer properties. This segmentation allows independent optimization of each layer's properties to achieve both coverage control and manufacturing precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the coating roll have different mechanical properties tailored to specific functions. The inner layer is designed to be softer and more deformable to conform to peak structures, while the outer layer is designed to be harder to maintain structural integrity and provide uniform coating transfer. This local differentiation of material properties enables precise control over coating application on patterned surfaces.

Inventive Principle:
Principle #3Local quality

2Quantity of substance

If the coating roll engages deeply with the substrate to ensure coverage, then coating coverage increases, but coating thickness becomes difficult to control and flooding occurs

Engineering Contradiction:
Improvecoating coverageVSAvoidcoating thickness control
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The coating roll employs dynamic deformation capabilities through its deformable inner layer that can adapt its contact pressure and engagement depth with the patterned substrate during coating application. This dynamic adjustment allows the system to maintain optimal coating coverage on peak structures while preventing excessive material transfer that would cause flooding, thereby controlling coating thickness precision.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system utilizes changes in the mechanical parameters of the coating roll layers, particularly the deformation characteristics of the inner layer, to control the coating process. By adjusting the deformability and engagement depth parameters, the system can regulate the amount of coating material transferred to the substrate, achieving both adequate coverage and precise thickness control without flooding.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If a soft coating roll is used to conform to patterned surfaces, then coating uniformity on peaks improves, but the roll loses structural integrity and coating thickness control

Engineering Contradiction:
Improvecoating uniformityVSAvoidroll structural integrity
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The coating roll is constructed as a composite structure combining a deformable inner layer with a deformable outer layer, each made from materials with appropriate mechanical properties. The inner layer uses softer, more compliant material to conform to the substrate's peak structures, while the outer layer uses harder material to maintain structural integrity and provide controlled coating transfer. This composite approach resolves the contradiction between conformability and structural strength.

Inventive Principle:
Principle #40Composite materials

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 deformable coating roll system allows for improved control over coating uniformity and coverage on patterned surfaces by applying coating only to the peaks, reducing flooding and enhancing process window, while decoupling engagement depth and coating thickness control.

Implementation Method 1

a deformable inner layer with a surface thereof covered by a deformable outer layer, the inner layer being softer than the outer layer

Methodology Applied
Scientific EffectDeformation: Deformation

Implementation Method 2

the inner layer being softer than the outer layer

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

transferring a coating material from the coating roll to the substrate at the nip

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4271885B1Method of coating a patterned structure on a substrate
Publication Date: 2025.09.24 3M INNOVATIVE PROPERTIES CO
  • EP4271885B1 patent drawingFigure 1'
  • EP4271885B1 patent drawingFigure 1
  • EP4271885B1 patent drawingFigure 2A

AI summary

Methods and apparatuses for roll coating are provided. The roll coating system (100) includes a coating roll (110) having a deformable inner layer (12) with a surface thereof covered by a deformable outer layer (14), the inner layer being softer than the outer layer. A substrate (3) is conveyed to the nip (12) between the coating roll and a back-up roll (120). A metered coating material is transferred from the coating roll to a patterned surface structure (40) of the substrate at the nip to form a conformal coating on the patterned structure of the substrate.