Fabry-Perot Interferometer Gas Analysis Device
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Solution Overview
Problem
Current anesthesia ventilation gas analysis devices are complex and costly, with limited accuracy in determining concentrations of multiple anesthetic gases due to cumbersome filter banks and high pneumatic time constants, which can lead to inaccurate measurements during abrupt changes in gas concentrations.
Innovation Solution
A device utilizing a Fabry-Perot interferometer with a band pass filter function that scans a predefined wavelength range to detect various anesthetic gases and adjusts to preferred wavelengths for higher temporal resolution concentration measurements, allowing for precise detection and measurement of multiple anesthetic gases with reduced measurement duration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a filter bank with multiple detectors and filters is used for each wavelength, then selective determination of individual gas concentrations is improved, but device complexity and manufacturing cost increase significantly
Solution Approach 1:
The patent employs a single detector that serves multiple functions by sequentially measuring absorbance at different wavelengths. Instead of requiring multiple detectors each with dedicated filters, one detector is used with a scanning monochromator to provide wavelength-selective measurements, thereby reducing device complexity while maintaining measurement precision for multiple gas components
Solution Approach 2:
The patent uses a scanning monochromator with a movable grating that dynamically adjusts the wavelength of light reaching the detector. This dynamic wavelength selection allows the system to sequentially measure different gas components at their respective absorption wavelengths, replacing the static filter bank approach with a dynamic, reconfigurable optical path
2Adaptability or versatility
If a filter wheel is used to change wavelengths reaching the detector, then wavelength selection is improved, but mechanical wear increases due to rotating components
Solution Approach 1:
The patent replaces the mechanical filter wheel system with a scanning monochromator that uses a rotating grating in a controlled angular range. While this still involves rotation, the grating rotates within a limited arc to change the diffraction angle, allowing wavelength selection without the need for a full filter wheel rotation, thereby reducing mechanical wear and improving reliability
3Measurement precision
If multiple partial cuvettes connected in series are used, then absorption measurements at different wavelengths are improved, but pneumatic time constant increases leading to inaccurate determination during abrupt concentration changes
Solution Approach 1:
The patent employs a single gas cuvette with a scanning monochromator that dynamically changes the wavelength of light passing through the gas sample. This allows absorption measurements at multiple wavelengths to be performed sequentially through optical modulation rather than requiring multiple physical cuvettes in series, thereby maintaining measurement precision while significantly reducing the pneumatic time constant and improving response speed to abrupt concentration 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
The device provides accurate and efficient analysis of anesthesia ventilation gas concentrations with improved temporal resolution, enabling precise monitoring of anesthetic gas mixtures and reducing the complexity and cost associated with traditional methods.
Implementation Method 1
A device utilizing a Fabry-Perot interferometer with a band pass filter function that scans a predefined wavelength range
Implementation Method 2
A determination of the particular concentrations of respective types of anesthetic gas is performed here according to the state of the art optically on the basis of a determination of the absorption of optical radiation of certain wavelengths
Data Source
AI summary
A device analyzes an anesthesia ventilation gas with an infrared radiation source and includes a gas cuvette, a Fabry-Perot interferometer with a band pass filter function, adjustable with respect to a central transmission wavelength as a function of a control signal, a detector providing a measured signal and a computing and control unit providing the control signal and detecting the measured signal. The computing and control unit is configured to actuate the Fabry-Perot interferometer in a first operating mode by the control signal such that the central transmission wavelength scans a predefined wavelength range, to detect a presence in the ventilation gas sample potential types of anesthetic gases based on the measured signal. In a second operating mode, the control unit controls the central transmission wavelength within a subrange of the predefined wavelength range and determines a plurality of concentration values at consecutive times for detected types of anesthetic gases.