Optical Gas Sensor Deflection Structures
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Solution Overview
Problem
Existing optical alley sensors face challenges in achieving a compact design while maximizing the use of emitted radiation for gas concentration measurement, as a significant portion of radiation escapes through the air exchange hole, resulting in a weak utility signal.
Innovation Solution
The optical alley sensor features a measurement cell with a light channel and deflection structures, such as pyramidal entry- and exit-side deflectors, that redirect radiation along the longitudinal direction, ensuring almost all emitted radiation reaches the detector, and a gas passage area is designed to minimize optical losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the light channel is designed with air exchange holes for gas passage, then gas can be introduced into the measurement cell, but a significant portion of radiation escapes through these holes, resulting in weak utility signal
Solution Approach 1:
A membrane is introduced as an intermediary component in the gas passage area, allowing gas molecules to pass through while blocking electromagnetic radiation. This mediator enables simultaneous achievement of gas access and radiation containment, resolving the contradiction between gas passage capability and radiation loss.
Solution Approach 2:
The patent employs porous or permeable membrane materials in the gas passage area that are selectively permeable to gas molecules but opaque to infrared radiation. This allows gas to be introduced into the measurement cell while preventing radiation escape, thus reducing energy loss while maintaining adaptability.
2Volume of moving object
If the optical alley sensor is designed to be compact and flat, then the device size is reduced, but the light channel geometry becomes constrained, making it difficult to redirect all radiation to the detector
Solution Approach 1:
The patent utilizes the third dimension (vertical depth) within the compact footprint by implementing pyramidal deflection structures that redirect radiation through multiple bounces within the light channel. This dimensional approach allows effective radiation management in a flattened, compact device geometry.
Solution Approach 2:
Pyramidal deflection structures with angled surfaces are employed to redirect radiation through curved reflection paths rather than straight lines. These geometric features enable radiation to be redirected multiple times within the constrained compact volume, ensuring maximum radiation reaches the detector despite the flat device profile.
3Loss of energy
If pyramidal deflection structures are used to redirect radiation, then radiation is effectively redirected towards the detector, but the manufacturing complexity of the measurement cell increases
Solution Approach 1:
The pyramidal deflection structures are integrated directly into the measurement cell body as a unified component rather than separate parts. This merging of functions allows the deflection geometry to be formed during the primary manufacturing process (such as injection molding), reducing assembly steps and overall manufacturing complexity while maintaining effective radiation redirection.
Solution Approach 2:
The measurement cell structure serves multiple functions simultaneously: it contains the light channel, provides structural support, and incorporates the pyramidal deflection surfaces for radiation redirection. This multi-functionality reduces the total number of components and simplifies manufacturing by combining several functions into a single manufacturable part.
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 design results in a highly efficient optical alley sensor with a flat profile, ensuring maximum radiation usage and minimal losses, allowing for precise gas concentration measurements.
Implementation Method 1
The electromagnetic radiation emitted by the radiation source in a suitable spectral area goes through the measuring cell and is partially absorbed by the gas, the concentration of which should be measured.
Implementation Method 2
The detection of gases through absorption measurements in the middle infrared area with the help of optical alley sensors (NDIR spectroscopy) is an established procedure for the exact determination of gas concentrations
Implementation Method 3
In the light channel, a majority of reflective surfaces with a certain geometry are intended, through which the radiation that is coupled therein is redirected several times before it meets a detector.
Implementation Method 4
The at least one deflection of entry -sided deflection is formed in a pyramid manner and arranged on a long side of the measuring cell, whereby the pyramid tip is oriented towards the radiation source.
Data Source
Figure 1
Figure 2a~2d
Figure 3~4b
AI summary
An optical gas sensor for determining gas concentration is described. This sensor comprises a measuring cell, a radiation source, and at least one detector. The measuring cell for receiving the gas includes a light channel extending along a longitudinal direction. The radiation source emits electromagnetic radiation onto the gas in the measuring cell, the radiation source being located in a light entry region of the measuring cell and emitting radiation in the direction of the light channel. At least one detector serves to detect at least portions of the electromagnetic radiation that have passed through the gas, the at least one detector being located in a light exit region.The measuring cell contains at least one deflecting element which deflects the incident radiation both directly and indirectly along the longitudinal direction of the light channel towards the at least one detector, and/or deflects the radiation propagating along the longitudinal direction of the light channel both directly and indirectly towards the at least one detector (Fig. 1).