Sub-Micron Particle Cleanliness Testing With Spiral Airflow Containment
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Solution Overview
Problem
Existing methods for detecting sub-micron particles are limited in sensitivity, with visual inspection techniques only detecting particles larger than twenty microns and laser detection systems failing to effectively quantify smaller particles, while existing apparatuses do not efficiently prevent particle escape during analysis.
Innovation Solution
A system utilizing a chamber with HEPA/ULPA filters, controlled air flow, and high-pressure air pulses to impinge on a sample, combined with particle counters, ensures accurate detection and containment of sub-micron particles by introducing clean air in a downwards spiral motion to prevent upward escape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If visual inspection techniques with ultraviolet or white light are used, then the inspection method is simple and easy to operate, but only particles larger than twenty microns can be detected
Solution Approach 1:
The patent replaces visual inspection methods (optical/mechanical system) with laser detection technology. The laser beam interacts with particles to produce light scattering signals that can be detected and measured, enabling precise detection of sub-micron particles that are invisible to conventional visual inspection methods.
Solution Approach 2:
The patent changes the detection parameter from visual light detection to laser light scattering detection. By using laser illumination and measuring the intensity of scattered light, the system can detect particles much smaller than the wavelength of visible light, achieving detection of particles down to 0.1 microns or smaller.
2Measurement precision
If laser detection systems are used to detect particles smaller than one micron, then measurement precision is improved, but particle escape during analysis cannot be prevented
Solution Approach 1:
The patent introduces clean air flow as an intermediary medium between the particle source and the detection environment. The controlled air flow serves multiple functions: it transports particles to the detection zone, maintains a clean environment, and prevents particle escape while allowing laser detection to proceed accurately.
Solution Approach 2:
The patent creates a controlled air environment within the inspection chamber that acts as an inert medium for particle analysis. By maintaining controlled air flow and pressure conditions, the system prevents particle escape and contamination while enabling accurate laser detection of sub-micron particles.
3Measurement precision
If conventional particle counters are used, then sub-micron particle detection is enabled, but the system cannot effectively contain and prevent particle escape during analysis
Solution Approach 1:
The patent designs the inspection chamber to serve multiple functions simultaneously: it contains particles during analysis, provides controlled air flow to prevent escape, maintains clean environment, and facilitates laser detection. This multi-functional design achieves particle containment without requiring separate complex containment systems.
Solution Approach 2:
The patent uses controlled air flow (pneumatics) to manage particle containment and transport. By regulating air pressure and flow patterns within the chamber, the system prevents particle escape while maintaining detection accuracy, replacing the need for mechanical containment barriers with a more elegant pneumatic control 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 precise quantification of sub-micron particles on a sample surface, maintaining cleanliness standards by effectively capturing and counting particles down to 0.1 microns, enhancing sensitivity and reliability in clean room environments.
Implementation Method 1
particle counters based on laser detection system
Implementation Method 2
chamber with HEPA/ULPA filters
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
The present invention provides systems and methods for determining the cleanliness of a sample, the method including impinging high pressure fluid pulses on a sample disposed in a chamber to liberate particles therefrom and quantifying a number of the liberated particles to determine the cleanliness of the sample.