Periodic Electrode Thermal Infrared Sensor for Gas Detection
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Solution Overview
Problem
Existing thermal infrared sensors for gas measurement require expensive band-pass optical filters to selectively measure gases, increasing the size and cost of gas measuring apparatuses.
Innovation Solution
A thermal infrared sensor with a pyroelectric material layer and a light-receiving surface electrode having a periodic structure that selectively absorbs infrared light at specific wavelengths, eliminating the need for band-pass optical filters by functioning as a band-pass optical filter itself.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a band-pass optical filter is used to selectively detect specific gas wavelengths, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines the optical filter function with the electrode structure by creating a periodic pattern on the light-receiving surface electrode. This integration eliminates the need for separate band-pass optical filters, as the periodic electrode structure itself performs wavelength selection through its diffraction grating effect, thereby reducing device complexity while maintaining measurement precision
Solution Approach 2:
The light-receiving surface electrode is designed to serve multiple functions: it acts as both the electrical contact for the pyroelectric sensor and as a wavelength-selective optical element. The periodic structure enables the electrode to function as a diffraction grating that selectively directs specific wavelengths to the sensing region, making the electrode a multi-functional component that reduces overall device complexity
2Measurement precision
If multiple band-pass optical filters are used for reference and detection, then measurement precision is improved, but the size of the apparatus increases
Solution Approach 1:
The patent merges the functions of multiple optical filters into a single periodic electrode structure. By using the periodic pattern on the light-receiving surface electrode as a common diffraction grating for both reference and detection channels, the design eliminates the need for multiple separate band-pass filters, thereby reducing the apparatus size while maintaining the ability to perform selective wavelength detection and reference measurements
Solution Approach 2:
The periodic structure on the light-receiving surface electrode creates localized wavelength selection at the sensor interface. Different regions of the periodic pattern can be designed to handle different wavelength selections for reference and detection channels, enabling multi-wavelength measurement functionality within a compact footprint without requiring multiple bulk optical filters
3Measurement precision
If expensive band-pass optical filters are used, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent combines the optical filter function with the electrode structure by creating a periodic pattern on the light-receiving surface electrode. This integration eliminates the need for expensive separate band-pass optical filters, as the periodic electrode structure itself performs wavelength selection through its diffraction grating effect, thereby reducing component costs while maintaining wavelength-selective detection capability
Solution Approach 2:
The periodic structure on the electrode can be manufactured using standard semiconductor fabrication techniques such as photolithography, which are more cost-effective than traditional optical filter manufacturing. This approach replaces expensive optical components with a patterned metal layer that can be produced at lower cost through established manufacturing processes
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 reduces the size and component costs of gas measuring apparatuses while maintaining high sensitivity and accuracy in measuring gases like CO2, achieving a compact and cost-effective solution for gas measurement.
Implementation Method 1
a sensor (a thermal detection layer, such as a pyroelectric material layer) itself has a low wavelength dependence
Implementation Method 2
The light-receiving surface electrode has a periodic structure for selectively absorbing infrared light having an absorption wavelength of a sample gas
Data Source
AI summary
A thermal infrared sensor for gas measurement including a sensing element. The sensing element includes a thermal detection layer that outputs an electric signal based on a temperature change, a light-receiving surface electrode disposed on a light-receiving surface of the thermal detection layer, and a back electrode disposed on the thermal detection layer opposite the light-receiving surface electrode. The light-receiving surface electrode has a periodic structure configured to selectively absorb infrared light having an absorption wavelength of a sample gas.