Spectroscopic Analysis Device Using Polarized Light Separation

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Solution Overview

Problem

Existing spectroscopic analysis methods struggle to accurately analyze the composition and composition ratio of a measurement target object's surface due to disturbances such as changes in reflection intensity, atmospheric changes, dirt, light source fluctuations, and vibrations.

Innovation Solution

A spectroscopic analysis apparatus and method that utilize infrared light to analyze the surface composition by separating reflected light into s-polarized and p-polarized components, calculating absorbance based on their intensity ratio, and correcting for disturbances using a distance measuring unit and position adjustment mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the reflection spectrum intensity of s-polarized light is measured repeatedly to account for disturbances, then measurement accuracy may improve, but measurement time increases and productivity decreases

Engineering Contradiction:
Improveaccuracy of intensity ratio calculationVSAvoidmeasurement cycle speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent combines the measurement of s-polarized light and p-polarized light into a single simultaneous measurement process using a beam splitter and multiple detectors. This eliminates the need for repeated alternating measurements while maintaining the ability to calculate accurate intensity ratios, thus resolving the contradiction between measurement precision and productivity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements continuous measurement by simultaneously detecting both s-polarized and p-polarized light components in real-time. This continuous action eliminates measurement interruptions and switching delays, maintaining measurement accuracy while maximizing measurement speed and productivity.

Inventive Principle:
Principle #20Continuity of useful action

2Measurement precision

If polarizers are switched frequently to measure s-polarized and p-polarized light alternately, then composition analysis accuracy may improve, but process time increases and unmeasurable area expands

Engineering Contradiction:
Improveaccuracy of composition analysisVSAvoidtime for switching polarizers
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent merges the functions of measuring s-polarized light and p-polarized light into a single optical path using a beam splitter. Both polarized components are directed to separate detectors simultaneously, eliminating the time-consuming process of switching polarizers while maintaining accurate composition analysis.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces the mechanical switching system of polarizers with an optical beam splitter system that simultaneously separates and directs both s-polarized and p-polarized light to different detectors. This substitution eliminates mechanical switching delays and expands the measurable area.

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

3Device complexity

If a gold mirror is used as reference assuming s-polarized light reflectance is approximately 1, then device complexity is reduced, but measurement accuracy deteriorates when disturbances occur

Engineering Contradiction:
Improvesimplicity of reference measurement systemVSAvoidaccuracy of intensity ratio under disturbance
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent uses the measurement target object itself as the reference by comparing s-polarized and p-polarized light reflection from the same surface. This self-referential approach eliminates the need for external gold mirror references while maintaining measurement accuracy even under disturbance conditions.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent implements a feedback mechanism by simultaneously measuring both s-polarized and p-polarized light intensities and using their ratio to compensate for disturbances. The system continuously monitors and adjusts for variations in reflection intensity, atmospheric changes, and other disturbances through real-time comparison of the two polarized components.

Inventive Principle:
Principle #23Feedback

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

Enables high-accuracy analysis of surface composition and composition ratio even in the presence of disturbances, facilitating the production of steel strips with desired surface properties and ensuring high-quality steel strips.

Implementation Method 1

a separator configured to separate the reflected light into s-polarized light and p-polarized light

Methodology Applied
Scientific EffectPolarization separation: Polarisation

Implementation Method 2

a detector for s-polarized light configured to detect s-polarized light obtained through the separation by the separator and output an electric signal indicating an intensity of the s-polarized light

Methodology Applied
Scientific EffectPhotoelectric detection: Photoelectric Effect

Implementation Method 3

calculate an absorbance based on a ratio between the intensities of the s-polarized light and the p-polarized light

Methodology Applied
Scientific EffectReflectance ratio measurement: Reflection

Data Source

PatentEP3742152B1Spectroscopic analysis device, spectroscopic analysis method, method for manufacturing steel strip, and steel strip quality assurance method
Publication Date: 2025.04.23 JFE STEEL CORP
  • EP3742152B1 patent drawingFigure 1
  • EP3742152B1 patent drawingFigure 2
  • EP3742152B1 patent drawingFigure 3~4

AI summary

A light receiving unit 3 includes: a polarized-light separating unit 32 configured to separate reflected light into s-polarized light and p-polarized light; an s-polarized light detecting unit 34 configured to detect s-polarized light obtained through the separation by the polarized-light separating unit 32 and output an electric signal indicating the intensity of the detected s-polarized light to an output unit 4; and a p-polarized light detecting unit 33 configured to detect p-polarized light obtained through the separation by the polarized-light separating unit 32 and output an electric signal indicating the intensity of the detected p-polarized light to the output unit 4. The output unit 4 calculates an absorbance from the intensity ratio between the s-polarized light and the p-polarized light from respective electric signals output from the s-polarized light detecting unit 34 and the p-polarized light detecting unit 33, and calculates either or both of the composition and the composition ratio of the surface of a measurement target object P using the intensity of an absorbance corresponding to any desirable wavenumber.