Aspherical Mirror Aberration for Micro Particle Detection Accuracy

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Solution Overview

Problem

Conventional micro object detection apparatuses using converging mirrors face challenges in accurately detecting polarized light components due to changes in polarization direction and reflectance, leading to reduced accuracy in detecting micro particulate matter and pollen, and suffer from erroneous counting of particles due to light blocking effects.

Innovation Solution

The apparatus employs an aspherical second converging mirror that generates aberration, improving the efficiency and accuracy of scattered light collection and detection by dispersing focal points, thereby reducing light blocking and miscounting of particles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a converging mirror is used to collect scattered light, then the light collection efficiency is improved, but the polarization direction changes and reflectance varies causing reduced detection accuracy

Engineering Contradiction:
Improvelight collection efficiencyVSAvoidpolarized light detection accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent extracts the polarized light detection function from the light collection function by using two separate optical systems: one for collecting scattered light and another for detecting polarized light components, thereby avoiding the interference of mirror reflection on polarization measurement

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The detection system is segmented into multiple independent optical paths: a light collection optical system using converging mirrors, and a polarized light detection optical system using a polarization beam splitter and detectors, allowing each system to optimize its function without interfering with the other

Inventive Principle:
Principle #1Segmentation

2Device complexity

If a single optical system is used for both light collection and polarized light detection, then the device complexity is reduced, but the detection accuracy of both functions deteriorates

Engineering Contradiction:
Improveoptical system structureVSAvoiddetection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent creates a multi-functional integrated detection apparatus that combines particle detection, light collection, and polarized light analysis functions within a single device structure, using coordinate transformation to enable comprehensive particle characterization without requiring multiple separate instruments

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

3Ease of manufacture

If conventional optical systems are used, then the manufacturing cost is reduced, but the ability to detect both micro particulate matter and pollen is compromised

Engineering Contradiction:
Improvemanufacturing costVSAvoiddetection capability for different particle types
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent changes the detection parameters by measuring both the intensity of scattered light and the polarization state of scattered light, enabling differentiation between particle types (micro particulate matter versus pollen) based on their distinct optical properties without requiring separate detection devices

Inventive Principle:
Principle #35Parameter changes

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

This configuration enhances the detection efficiency and accuracy of micro particles by effectively directing scattered light to the reception element and minimizing erroneous particle counting, improving the measurement of number and weight concentrations.

Implementation Method 1

an aspherical second converging mirror that generates aberration, improving the efficiency and accuracy of scattered light collection and detection by dispersing focal points

Methodology Applied
Scientific EffectOptical aberration:

Implementation Method 2

the scattered light is reflected in an oblique direction by the converging mirror

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 3

irradiates with light a space in which suspended micro particulate matter (hereinafter referred to as 'particle(s)') such as pollen or dust exists, detects scattered light generated at that time

Methodology Applied
Scientific EffectLight scattering: Scattering

Data Source

PatentEP3761008B1Micro object detection apparatus
Publication Date: 2023.06.14 MITSUBISHI ELECTRIC CORP
  • EP3761008B1 patent drawingFigure 1
  • EP3761008B1 patent drawingFigure 2
  • EP3761008B1 patent drawingFigure 3

AI summary

A micro object detection apparatus comprising: a first optical system (52a) that includes a first reflection region (103), a second reflection region (104), and a first light reception element (6), and directs scattered light scattered when irradiation light hits a particle, to the first light reception element (6), by reflecting the scattered light by the first reflection region (103) and the second reflection region (104); and a second optical system (52b) that receives the scattered light, wherein the scattered light is directed to the first light reception element (6) by providing a first passage region (H) in the second reflection region (104) and is directed to the second optical system (52b) by providing a second passage region (AP) in the first reflection region (103), and the second passage region (AP) is located to face the first passage region (H).