Optical Coating Thickness Measurement on Moving Roll-Fed Substrates

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Solution Overview

Problem

Conventional separator coating devices suffer from low accuracy in measuring the thickness of coating materials due to noise from vibration and temperature fluctuations, and the use of isotope sources leads to inaccurate estimation of actual coating thickness.

Innovation Solution

A coating thickness measuring device that includes a light applying unit, a light acquisition unit, and a processor to measure the thickness of the coating material applied to a substrate, with modules that can move in 3-axis directions and adjust distance, and a position movement module to minimize substrate shake and correct for temperature and roundness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional replacement sensors are used to measure coating thickness, then measurement can be performed, but measurement accuracy deteriorates due to noise from vibration and temperature

Engineering Contradiction:

Improvecoating thickness measurement accuracyVSAvoidvibration noise and temperature fluctuations

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces conventional mechanical/contact-based replacement sensors with a non-contact optical measurement system. The optical sensor measures coating thickness by detecting light reflection from the coating surface, eliminating mechanical contact that causes vibration noise. This substitution of measurement principle resolves the contradiction by maintaining measurement capability while removing the source of vibration interference.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the measurement parameter from electrical resistance (conventional sensors) to optical reflection properties. By measuring how light reflects off the coating surface rather than using electrical contacts, the system becomes insensitive to temperature fluctuations and vibration, thereby improving measurement accuracy under adverse environmental conditions.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If isotope sources are used for substrate permeation measurement, then substrate thickness can be measured, but actual coating thickness measurement accuracy deteriorates

Engineering Contradiction:

Improveactual coating thickness measurement accuracyVSAvoiddirect coating thickness data

Core Design Contradiction:

Measurement precisionVSLoss of information

Solution Approach 1:

The patent replaces the indirect isotope-based measurement method with direct optical measurement. Instead of measuring substrate permeation and calculating coating thickness indirectly, the optical sensor directly measures the coating surface reflection to obtain accurate coating thickness data, eliminating information loss in the calculation process.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Area of stationary object

If replacement sensors scan in the widthwise direction of substrate, then coverage is improved, but measurement accuracy deteriorates due to large amount of data required and processing complexity

Engineering Contradiction:

Improvemeasurement coverage areaVSAvoidactual coating thickness measurement accuracy

Core Design Contradiction:

Area of stationary objectVSMeasurement precision

Solution Approach 1:

The optical measurement system performs multiple functions simultaneously: it measures coating thickness accurately while also providing real-time feedback for process control. The system can measure both local thickness variations and overall coating quality, eliminating the need for separate measurement passes and reducing data processing requirements.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

Improves the accuracy of coating thickness measurement by minimizing the influence of substrate shake and temperature fluctuations, allowing for precise measurement of coating material thickness.

Implementation Method 1

a light applying unit configured to apply light to a surface of the coating material applied to a portion of the substrate rolled on the coating roll; a light acquisition unit configured to acquire light reflected from the surface of the coating material

Methodology Applied

Scientific EffectLight reflection: Reflection

Data Source

PatentUS20250231020A1Coating Thickness Measuring Device and Coating Device Including the Same

Publication Date: 2025.07.17 LG CHEM LTD

AI summary

A coating thickness measuring device is configured to measure a thickness of a coating material applied to a substrate which is fed by a coating roll on which the substrate is rolled. The coating thickness measuring device includes a coating thickness measurement module, wherein the coating thickness measurement module includes a light applying unit configured to apply light to a surface of the coating material applied to a portion of the substrate rolled on the coating roll, a light acquisition unit configured to acquire light reflected from the surface of the coating material, and a processor configured to calculate the thickness of the coating material based on the acquired light. Accordingly, when measuring the thickness of the coating material the thickness measurement accuracy may be improved. A coating device including the same is also provided.