Circular Polarized Light Sensing for Transparent Product Detection

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Solution Overview

Problem

Existing sensing methods using polarized light struggle with sensitivity and erroneous sensing when detecting transparent products, particularly with circularly polarized light, as they require complex adjustments and do not effectively differentiate between transparent and opaque materials.

Innovation Solution

A sensing method utilizing circularly polarized light with a system that includes a light source, a circularly polarized light separation film, and a detection unit, where the light intensity is enhanced by adjusting the sense of the polarized light to oppose or match the polarized light transmitted through the target object, allowing for high sensitivity and reduced erroneous sensing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If linear polarizing filters are used for sensing, then polarization direction adjustment is required, but the operation becomes complex and sensitivity is reduced

Engineering Contradiction:
Improvesensing sensitivityVSAvoidpolarization direction adjustment
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The invention changes the polarization parameter from linear to circular polarization. By using circularly polarized light instead of linearly polarized light, the system eliminates the need for polarization direction adjustment while maintaining high sensing sensitivity. The circular polarization state remains invariant under rotation, solving the operational complexity issue.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If circularly polarized light is used for sensing transparent products, then sensitivity should be improved, but erroneous sensing occurs

Engineering Contradiction:
Improvesensing sensitivityVSAvoiderroneous sensing
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The invention introduces a circular polarizing plate as an intermediary component between the light source and the transparent product. This plate converts linearly polarized light from the source into circularly polarized light, which then interacts with the birefringent transparent product. The circular polarization state serves as a mediator that enhances sensitivity while reducing erroneous sensing through the birefringence effect.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the polarization parameter from linear to circular polarization and utilizes the birefringence property of transparent products. By detecting changes in the circular polarization state after light passes through the transparent product, the system achieves high sensitivity while reducing erroneous sensing, as the birefringence effect provides a reliable differentiation mechanism between transparent and opaque materials.

Inventive Principle:
Principle #35Parameter changes

3Difficulty of detecting and measuring

If polarized light sensing is used to differentiate transparent and opaque materials, then detection capability should be improved, but complex adjustments are required

Engineering Contradiction:
Improvematerial differentiation capabilityVSAvoidadjustment mechanism
Core Design Contradiction:
Difficulty of detecting and measuringVSDevice complexity

Solution Approach 1:

The invention changes the polarization parameter from linear to circular polarization and exploits the birefringence property of transparent materials. This parameter change enables automatic material differentiation without complex adjustments, as the circular polarization state naturally interacts with the birefringent structure of transparent materials to produce detectable signals.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The transparent product itself serves as the differentiating mechanism through its inherent birefringence property. The product's optical properties automatically modulate the circularly polarized light passing through it, eliminating the need for external adjustment mechanisms. The system leverages the material's own characteristics to achieve differentiation.

Inventive Principle:
Principle #25Self-service

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 method achieves high sensitivity in detecting transparent products with reduced erroneous sensing by utilizing circularly polarized light, increasing light intensity through birefringence effects, and distinguishing between transparent and opaque materials effectively.

Implementation Method 1

the light intensity is enhanced by adjusting the sense of the polarized light to oppose or match the polarized light transmitted through the target object, allowing for high sensitivity and reduced erroneous sensing

Methodology Applied
Scientific EffectBirefringence: Birefringence

Data Source

PatentEP3287766B1Detection method and detection system
Publication Date: 2023.03.15 FUJIFILM CORP
  • EP3287766B1 patent drawingFigure 1A~1B
  • EP3287766B1 patent drawingFigure 1C~1D
  • EP3287766B1 patent drawingFigure 2A~2B

AI summary

A sensing method includes sensing the target object by sensing light that is derived from emitted light and has passed the target object, in which the emitted light is circularly polarized light, sensed light is circularly polarized light, and light derived from the emitted light is incident to the target object at an angle greater than 20° and equal to or smaller than 70° that is formed with a normal line of the target object.