NDIR Liquid Molecule Detection via Pulsed Beam Scanning
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Solution Overview
Problem
Existing NDIR methods face challenges in accurately detecting molecules in liquid media due to high molecular density, scattering noise, and interference from interfering molecules, with limited sample volume and non-homogenous structures like human tissue, which affect detection accuracy and precision.
Innovation Solution
The method employs a multiplexer and collimator to pulse infrared radiation from signal, interference, and reference sources into a pulsed beam, varying its angle to penetrate a liquid sampling matrix, using a detector to process signals and calculate the concentration of targeted molecules by validating a calibration curve, while minimizing scattering and absorption interference noise through specific wavelength selection and beam scanning techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If NDIR is used to detect molecules in liquid media, then detection capability is achieved, but scattering noise and interference from interfering molecules reduce measurement precision
Solution Approach 1:
The patent segments the detection process into multiple wavelength measurements. By measuring at multiple specific wavelengths (including the target wavelength and reference wavelengths), the system can separate the absorption signal of the target molecule from scattering noise and interfering molecule signals, thereby improving measurement precision in the presence of harmful factors.
Solution Approach 2:
The patent introduces reference wavelengths as intermediary measurements. These reference wavelengths are selected to be absorbed by interfering molecules or affected by scattering but not by the target molecule. By using these intermediaries, the system can mathematically subtract the harmful effects from the target measurement, resolving the contradiction between detection capability and noise interference.
2Reliability
If beam scanning is used to account for non-homogenous structures, then detection reliability is improved, but device complexity increases
Solution Approach 1:
The patent employs dynamic beam scanning to adapt to non-homogenous liquid structures. By dynamically adjusting the beam position and scanning through multiple locations, the system captures representative samples from varying regions, improving detection reliability. This dynamic approach replaces static single-point measurement, accepting increased complexity for enhanced reliability.
3Measurement precision
If multiple wavelength measurements are performed to reduce interference, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The patent uses periodic modulation of the infrared sources at different wavelengths. By alternately activating signal and reference sources in a periodic manner, the system performs multiple wavelength measurements within a single measurement cycle. This periodic action allows simultaneous acquisition of multiple data points, improving precision while minimizing time loss through efficient time-multiplexed measurement.
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 approach enhances the accuracy, precision, and reliability of molecule detection in liquid media by reducing noise and accounting for non-homogenous structures, allowing for more comprehensive data capture and improved concentration measurement of molecules like glucose in interstitial fluid.
Implementation Method 1
Non-Dispersive Infra-Red (NDIR) is a common and excellent measurement technique for detecting gases in the atmosphere. NDIR sensors utilize the principle that various gas molecules exhibit substantial absorption at specific wavelengths in the infrared radiation spectrum.
Implementation Method 2
The term 'non-dispersive' as used herein refers to the apparatus used, typically a narrow-band optical or infrared transmission filter, instead of a dispersive element such as a prism or diffraction grating. The optical filter isolates the radiation in a particular wavelength band that coincides with a strong absorption band of a gas species for the purpose of said gas species measurement.
Implementation Method 3
Existing NDIR methods face challenges in accurately detecting molecules in liquid media due to high molecular density, scattering noise, and interference from interfering molecules
Data Source
AI summary
The concentration of a targeted molecule (such as glucose) in a liquid medium having at least one interfering molecule coexisting with the targeted molecule is detected by use of NDIR and a sampling technique in which an imposed location of a pulse beam from a signal source, an interference source and a reference source is varied over a plurality of sites of a sampling area.