Polarization Inspector Spatial Division for Thin Film Inspection

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Solution Overview

Problem

Conventional polarization inspectors are inefficient for inspecting the quality of organic thin films due to high inspection time, low light utilization efficiency, and large device configuration, especially when the inspection target is moving, as they require rotating analyzers and are not suitable for films with low surface reflectivity.

Innovation Solution

A compact and cost-effective polarization inspector that spatially divides reflected light into multiple beams with different polarization directions, allowing for independent measurement of elliptical azimuth angle, polarization degree, and polarization component intensity, enabling fast and efficient inspection of organic thin films without the need for rotating analyzers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a rotating analyzer is used to measure polarization conditions, then measurement precision is improved, but inspection time increases and productivity decreases

Engineering Contradiction:
Improvepolarization measurement precisionVSAvoidinspection speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent divides the polarization measurement into four separate detection channels, each equipped with a fixed polarizing beam splitter oriented at different angles (0°, 45°, 90°, 135°). This segmentation allows simultaneous measurement of multiple polarization components without mechanical rotation, resolving the contradiction between measurement precision and inspection speed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent replaces the mechanical rotating analyzer system with a static optical system using multiple fixed polarizing beam splitters. This substitution eliminates mechanical movement while maintaining measurement capability, thereby improving productivity without sacrificing measurement precision.

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

2Adaptability or versatility

If a rotating analyzer system is used, then comprehensive polarization analysis is achieved, but device complexity and size increase

Engineering Contradiction:
Improvepolarization analysis capabilityVSAvoiddevice configuration
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges four separate polarization detection channels into a single integrated detection system. By combining the optical paths and using a shared detector array, the system achieves comprehensive polarization analysis while reducing overall device complexity and size compared to four separate measurement systems.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a multi-functional detection system where a single detector array can measure all four polarization components simultaneously. This universal approach allows comprehensive polarization analysis without requiring separate dedicated systems for each measurement type, thereby reducing device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Productivity

If conventional polarization inspectors are used on moving targets, then inspection coverage is maintained, but light utilization efficiency decreases

Engineering Contradiction:
Improveinspection coverageVSAvoidlight utilization efficiency
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent enables continuous simultaneous measurement of all polarization components through the four-channel static system. This continuous action eliminates the time losses associated with rotating analyzers and ensures that light from moving targets is fully utilized for inspection, improving both productivity and light efficiency.

Inventive Principle:
Principle #20Continuity of useful action

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 rapid and accurate inspection of organic thin films, even when the target is moving, by improving light efficiency and reducing device size and cost, while maintaining high inspection quality.

Implementation Method 1

a polarizing beam splitter configured to divide the reflected light into a first divided light having a first polarization direction and a second divided light having a second polarization direction

Methodology Applied
Scientific EffectPolarization: Polarisation

Implementation Method 2

a quarter wave plate configured to convert the linearly polarized light into a circularly polarized light

Methodology Applied
Scientific EffectPhase difference:

Data Source

PatentEP3184995B1Polarization inspection device
Publication Date: 2021.09.01 YOKOGAWA ELECTRIC CORP
  • EP3184995B1 patent drawingFigure 1
  • EP3184995B1 patent drawingFigure 2
  • EP3184995B1 patent drawingFigure 3

AI summary

A polarization inspector for inspecting an inspection target, the polarization inspector having a polarization divider for spatially dividing at least a reflected beam of light from the inspection target by irradiating an illumination beam into divided beams of lights mutually different in polarization direction; one or more optical receivers for receiving the divided beams of lights and generating an image signal based on the divided beams of lights; and a processor for calculating at least one of an elliptical azimuth angle, a polarization degree and a polarization component intensity from the image signal.