Pyroelectric Sensor Array with Shared Window for Multi-Substance Detection
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Solution Overview
Problem
Existing multi-channel infrared sensor systems face challenges in miniaturization, optical throughput, and cost due to the need for multiple detectors and filters, which also suffer from optical crosstalk and thermal interference.
Innovation Solution
The arrangement of multiple pyroelectric infrared sensors and their associated filters within a common housing on a substrate with narrow mounting elements and a shared entrance window, along with compensation elements, enhances optical filling and minimizes crosstalk, while maintaining thermal decoupling and efficient radiation absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple individual sensors with separate housings are used to detect multiple substances, then the detection capability for different substances is improved, but the device complexity and space requirements increase
Solution Approach 1:
The patent combines multiple pyroelectric infrared sensors and their associated optical filters into a single common housing structure. The sensors are arranged in parallel on a substrate, sharing common components such as the housing, window, and electrical connections. This merging approach maintains the ability to detect multiple different substances while reducing overall device complexity and space requirements compared to using separate individual sensor housings.
Solution Approach 2:
The common housing structure serves multiple functions simultaneously: it provides mechanical support for all sensor elements, maintains thermal isolation for each detector, allows optical access through a shared window, and provides common electrical connections. This multi-functional design enables the system to handle multiple detection channels while using a unified structural platform, thereby reducing overall system complexity.
2Adaptability or versatility
If multiple individual sensors with separate housings are used to detect multiple substances, then the detection capability for different substances is improved, but the space requirements and manufacturing costs increase
Solution Approach 1:
The patent combines multiple pyroelectric infrared sensors and their associated optical filters into a single common housing structure. The sensors are arranged in parallel on a substrate, sharing common components such as the housing, window, and electrical connections. This merging approach maintains the ability to detect multiple different substances while reducing overall device complexity and space requirements compared to using separate individual sensor housings.
3Measurement precision
If detector elements are thermally insulated to increase sensitivity, then the detection sensitivity is improved, but the thermal time constant increases causing slower response
Solution Approach 1:
The patent segments the housing into individual sensor chambers, each containing a detector element with its own thermal isolation structure. This segmentation allows each detector to be optimized for thermal insulation independently, maximizing sensitivity without affecting the response time of other channels. The modular chamber design enables parallel operation of multiple sensors with optimized thermal characteristics.
4Use of energy by moving object
If a common housing with shared window is used for multiple sensors, then the optical throughput is improved, but the optical crosstalk between channels increases
Solution Approach 1:
The patent introduces narrow-band optical filters as intermediary elements between the common window and each detector element. These filters selectively transmit only the specific wavelength ranges corresponding to the absorption bands of target substances, allowing efficient use of the common optical path while preventing optical crosstalk between different detection channels. The filters act as wavelength-selective mediators that enable multi-channel detection through a shared optical entrance.
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 configuration allows for a compact, high-sensitivity, multi-channel sensor with increased optical throughput and reduced thermal interference, achieving efficient simultaneous detection of multiple substances while minimizing costs and space requirements.
Implementation Method 1
the incident radiation initially leads to an increase in temperature of the detector element through absorption
Implementation Method 2
the detector element consists of a pyroelectric crystal, such as lithium tantalate, which undergoes a change in spontaneous polarization with a change in temperature. The change in polarization in the crystal material leads to a displacement current that can be evaluated as an electrical voltage change or as an electrical current flow at the electrodes
Implementation Method 3
Defined areas are filtered out of the overall spectrum using special narrow-band bandpass filters and used to measure the substance-specific properties
Data Source
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AI summary
Device for the simultaneous determination of several different substances and/or substance concentrations and/or the properties of solids and/or their surfaces by means of n (with n ≥ 1) infrared sensors, wherein one pyroelectric infrared sensor, formed with a pyroelectric detector element and an associated optical filter, is assigned to each substance. The n pyroelectric detector element(s) and the associated optical filter(s) are arranged in a holder consisting of one or more identical holder elements within a housing on a substrate with electrical contacts applied thereto.A single common entrance window is arranged in the housing above the n pyroelectric detector element(s) and the associated filter(s), so that electromagnetic radiation strikes the n filter(s) and subsequently the n detector element(s) after passing through a material. The mounting element(s) is/are designed as a frame open towards the radiation source, and the radiation-sensitive surface(s) of the n detector element(s) and/or the n filter(s) are arranged therein parallel to the base of the mounting element(s). Support points for the n detector element(s) and/or the n filter(s) are formed in the mounting element(s), such that these are arranged at a distance from the base of the mounting element(s) and/or at a further distance from the opening of the mounting element(s) opposite the base.