Recycled Plastic Foreign Substance Imaging With Reflective Illumination

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Solution Overview

Problem

Existing methods for evaluating foreign substances in recycled plastic materials are inaccurate due to low clarity and manual inspection, which is impractical for high foreign substance content and difficult to measure sizes accurately.

Innovation Solution

A foreign substance detection device that includes a sample holder, illumination part, reflection part with a reflector, imaging part, and evaluation part, utilizing light emission and reflection to enhance clarity and accuracy of foreign substance evaluation, with a prism film to concentrate light and improve image processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual inspection with naked eye is used, then simplicity of operation is maintained, but measurement precision and reliability deteriorate due to low clarity of foreign substances in recycled plastic

Engineering Contradiction:
Improveforeign substance size measurement accuracyVSAvoiddetection system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

An imaging part (camera) is introduced as an intermediary between the human operator and the foreign substances. The camera captures images of the foreign substances in the recycled plastic, allowing for accurate measurement and evaluation without requiring direct visual inspection by the operator. This intermediary device overcomes the limitation of human visual acuity while maintaining operational simplicity through automated image analysis.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The manual visual inspection process is replaced with an automated imaging and image processing system. Instead of relying on human operators to visually identify and measure foreign substances, the system uses a camera to capture images and software to automatically analyze and measure the foreign substances, eliminating the need for manual measurement and improving precision.

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

2Measurement precision

If illumination is provided from one side only, then device complexity is reduced, but measurement precision deteriorates due to insufficient clarity of foreign substances

Engineering Contradiction:
Improveforeign substance clarityVSAvoidillumination system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The illumination system is segmented into multiple illumination parts positioned at different locations around the sample holder. Each illumination part provides light from a different angle, and their combined effect creates optimal lighting conditions for imaging the foreign substances. This segmentation allows for comprehensive illumination that enhances clarity without requiring a single complex illumination source.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The illumination approach transitions from single-sided (one-dimensional) to multi-sided (three-dimensional) lighting. By positioning illumination parts around the sample holder in different spatial dimensions, the system provides comprehensive lighting that eliminates shadows and enhances the visibility of foreign substances from multiple angles, improving measurement precision.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Illumination intensity

If reflector is added to enhance light reflection, then illumination intensity is improved, but device complexity increases

Engineering Contradiction:
Improvelight reflection efficiencyVSAvoidoptical system complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The reflector is designed to automatically utilize the light emitted by the illumination parts and redirect it toward the sample and imaging part. The reflector performs the function of light concentration and direction without requiring external control or adjustment mechanisms. It passively enhances the illumination intensity by reflecting existing light sources, improving efficiency without adding complex control systems.

Inventive Principle:
Principle #25Self-service

4Measurement precision

If prism film is interposed to concentrate light, then measurement precision is improved, but device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improveforeign substance boundary clarityVSAvoidassembly complexity
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

A prism film is introduced as an intermediary optical element between the reflector and the sample holder. The prism film concentrates and directs reflected light onto the foreign substances, enhancing their visibility and boundary definition. This intermediary component improves measurement precision by optimizing light distribution without requiring complex mechanical adjustment mechanisms.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Enhances the clarity of foreign substances in recycled plastic materials, allowing for accurate measurement of size and number, improving the efficiency of foreign substance detection.

Implementation Method 1

an illumination part configured to emit light toward the test sample on the sample holder

Methodology Applied
Scientific EffectLight emission: Light

Implementation Method 2

a reflection part provided with a reflector, which is disposed on an opposite side of the illumination part with respect to the sample holder and reflects light emitted from the illumination part toward the test sample

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 3

a prism film interposed between the sample holder and the reflector and configured to concentrate, onto the test sample, the light reflected from the reflector

Methodology Applied
Scientific EffectLight concentration: Prism

Data Source

PatentEP4729929A1Foreign substance detection device for recycled plastic material
Publication Date: 2026.04.22 LG CHEM LTD
  • EP4729929A1 patent drawingFigure 1
  • EP4729929A1 patent drawingFigure 2
  • EP4729929A1 patent drawingFigure 3

AI summary

The present disclosure relates to a foreign substance detection device for a recycled plastic material, which may enhance the clarity of a foreign substance contained in a test sample and thus improve the accuracy of foreign substance evaluation by emitting light toward the test sample, in a state in which a reflector is disposed on a bottom surface of a sample holder on which the test sample made of a recycled plastic material is placed.