Inline UV Concentration Meter Using Pulsed Light for Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional inline gas concentration meters, particularly infrared and ultraviolet absorption types, face issues with instability, low responsiveness, poor sensitivity, and measurement reproducibility, along with challenges in downsizing and cost reduction, especially when dealing with highly corrosive organic raw materials.
Innovation Solution
A compact ultraviolet light absorption type inline concentration meter utilizing a light source unit emitting mixed light with multiple wavelengths and a computing processor for frequency analysis of detection signals to compute fluid concentration, featuring a simplified optical system and reduced size, powered by LEDs or laser diodes, which significantly enhances measurement accuracy and reproducibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If infrared absorption type concentration meter is used, then gas concentration can be measured, but measurement stability deteriorates due to light source fluctuations
Solution Approach 1:
The patent applies periodic action by using pulsed light sources (LEDs or laser diodes) that emit light in periodic pulses rather than continuous illumination. This allows the system to measure absorbance during each pulse and average multiple measurements, reducing the impact of light source fluctuations and improving measurement stability. The periodic pulsing enables synchronous detection that filters out noise and stabilizes the concentration measurement.
Solution Approach 2:
The patent changes the operational parameters by using multiple wavelengths of light simultaneously or sequentially. By measuring absorbance at multiple wavelengths and applying mathematical processing (such as multi-wavelength analysis), the system can compensate for light source intensity variations and improve measurement reliability. This parameter change approach transforms the measurement from single-wavelength to multi-wavelength analysis.
2Measurement precision
If conventional absorption type concentration meter is used, then concentration measurement is possible, but responsiveness deteriorates due to averaging process
Solution Approach 1:
The patent uses periodic pulsed light sources that enable rapid sequential measurements at multiple wavelengths. Instead of averaging continuous signals which slows response, the pulsed approach allows the system to quickly cycle through wavelengths and compute concentrations in real-time, improving responsiveness while maintaining precision through the periodic measurement cycle.
Solution Approach 2:
The patent replaces conventional mechanical scanning systems (moving mirrors, rotating gratings) with a fixed multi-wavelength optical system using LEDs or laser diodes. This substitution eliminates mechanical inertia and moving parts, enabling faster wavelength switching and improving measurement speed and responsiveness while maintaining measurement precision through electronic control and signal processing.
3Measurement precision
If long light path cells are used, then measurement precision improves, but device size increases
Solution Approach 1:
The patent merges multiple light paths or multiple measurement functions into a single integrated detector assembly. By combining the functions of multiple cells or multiple wavelength measurements into one compact unit, the system achieves long effective light paths for precise measurement while maintaining a small physical footprint suitable for inline installation in semiconductor manufacturing equipment.
Solution Approach 2:
The patent transitions from a single linear light path to a multi-dimensional optical arrangement using multiple wavelengths and detection angles. By measuring absorbance at multiple wavelengths simultaneously or sequentially in a compact configuration, the system achieves the precision equivalent of long light paths without requiring physically long cells, thus reducing device volume.
4Measurement precision
If reference cell and sample cell are both provided, then measurement accuracy improves, but device complexity increases
Solution Approach 1:
The patent merges the reference cell and sample cell functions into a single integrated measurement chamber or uses a single cell design where reference and sample measurements are performed sequentially or simultaneously through optical switching. This consolidation maintains measurement accuracy by providing both reference and sample measurement capabilities while reducing the overall device complexity and number of components.
Solution Approach 2:
The patent designs a universal detector that can perform both reference measurement and sample measurement functions using the same optical path and detection system. By making the system multi-functional, it eliminates the need for separate dedicated reference and sample cells, reducing device complexity while maintaining the accuracy benefits of having both measurement capabilities.
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 solution provides high sensitivity, precision, and stability in gas concentration measurements, eliminating light source fluctuations and enabling cost-effective, compact designs with improved maintenance and airtightness, suitable for corrosive gases.
Implementation Method 1
an ultraviolet light absorption type inline concentration meter
Implementation Method 2
the absorbance of the gas in the sample cell 30a is measured and the concentration of the gas is computed by applying the Beer-Lambert law
Data Source
AI summary
An inline concentration meter includes a light source unit emitting mixed light containing at least two wavelengths with a phase difference, a detecting unit including a light incident part for entering the mixed light emitted from the light source unit into a fluid passage of a detector body and at least two light detection parts receiving the mixed light passed through the fluid passage, a computing processor unit conducting frequency analyzes of detection signals of the mixed light output from the respective light detection parts and computing variations of intensities of the detection signals corresponding to absorbances in at least two frequency ranges to compute a concentration of fluid in the fluid passage based on the variations of the intensities of the detection signals, and a recording/displaying unit recording and displaying a value of the fluid concentration computed at the computing processor unit.