Defective Particle Size Determination via Light Intensity Correction

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Solution Overview

Problem

Existing defective particle measurement methods cannot accurately determine the size of particles based solely on scattering intensity due to variations in light intensity distribution, leading to inefficiencies and longer measurement times.

Innovation Solution

A defective particle measurement apparatus and method that calculates position deviation from the focal point using in-plane intensity distribution, corrects light intensity, and determines particle size based on this correction, allowing for precise size determination and density distribution analysis with a single two-dimensional image.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple cross-sectional images are acquired to correct optical intensity distribution nonuniformity and determine particle size, then measurement precision is improved, but measurement time increases

Engineering Contradiction:

Improveparticle size determination accuracyVSAvoidmeasurement time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The invention changes the approach from acquiring multiple images at different depths to analyzing the intensity distribution within a single two-dimensional image. By computing position deviation from the focal point based on intensity distribution parameters and applying correction factors, the system achieves accurate particle size determination without temporal overhead of multiple acquisitions.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Instead of acquiring multiple cross-sectional images along the depth dimension (Z-axis), the invention extracts depth information (position deviation) from the intensity distribution within the two-dimensional image plane. This transforms a three-dimensional measurement problem into a two-dimensional analysis problem, reducing measurement time while maintaining precision.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Device complexity

If scattering intensity is used directly to determine defective particle size, then measurement process is simplified, but measurement precision deteriorates due to light intensity distribution variations

Engineering Contradiction:

Improvemeasurement process complexityVSAvoidparticle size determination accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The system computes position deviation from the focal point based on the intensity distribution of scattered light, then uses this feedback information to apply an appropriate correction factor. This feedback mechanism allows the system to compensate for optical intensity distribution variations automatically, maintaining measurement precision without significantly increasing process complexity.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The invention replaces the need for mechanical depth scanning (acquiring multiple cross-sectional images) with an optical analysis method. By analyzing the intensity distribution pattern in a single image and computing position deviation mathematically, the system substitutes mechanical movement with optical-field analysis, simplifying the measurement process while maintaining accuracy.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 precise determination of particle size and density distribution by correcting for light intensity variations, reducing measurement time and improving accuracy without the need for multiple cross-sectional images.

Implementation Method 1

irradiate focused laser light on a sample, image scattered light from the sample

Methodology Applied

Scientific EffectLight scattering: Scattering

Implementation Method 2

irradiate focused laser light on a sample

Methodology Applied

Scientific EffectLaser focusing: Laser

Data Source

PatentUS7633617B2Defective particle measuring apparatus and defective particle measuring method

Publication Date: 2009.12.15 OPTIMA

AI summary

A defective particle measuring apparatus that irradiates focused laser light on a sample, images scattered light from the sample, and measures defective particles in the sample based on the image result, includes a position deviation computing portion which, based on an in-plane intensity distribution of scattered light of each defective particle that is imaged, obtains a deviation from a focal point position on an image point side of the scattered light of each defective particle and calculates a position deviation amount in a depth direction of the defective particle corresponding to the deviation from the focal point position, a light intensity correcting portion for correcting the light intensity of the scattered light of the defective particle corresponding to the position deviation amount in the depth direction, and a size determining portion for determining the defective particle size based on the light intensity corrected by the light intensity correcting portion. Thus, the size of the defective particles can be determined at a high precision by a simple constitution in a short time, and density distribution of the defective particles can be obtained.