Pyroelectric Detector with Reducing Gas Barrier Layer
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Solution Overview
Problem
Pyroelectric detection devices face challenges in maintaining high detection characteristics due to oxygen deficit caused by reducing gases during manufacturing or use, which compromises the pyroelectric effects and heat dissipation, leading to degraded thermal separation properties.
Innovation Solution
A pyroelectric detector is designed with a reducing gas barrier layer made of materials like aluminum oxide (Al2O3) with lower thermal conductivity than SiN, covering the capacitor to prevent reducing gas penetration and enhance thermal separation, while also using a support member with a layered structure to reduce thermal conductivity and maintain reducing gas barrier properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a capacitor with high electrical conductivity electrodes (Pt, Ir) is used to achieve desired electrical characteristics, then electrical performance is improved, but thermal conductivity increases causing heat dissipation from the infrared detection element
Solution Approach 1:
The electrode structure is segmented into multiple layers with different materials and functions. The lower electrode uses high-conductivity Pt or Ir for electrical performance, while the upper electrode uses lower-conductivity Al for heat dissipation control. This segmentation allows each layer to optimize its specific function without compromising the other.
Solution Approach 2:
Different regions of the electrode structure have different thermal conductivity properties tailored to local requirements. The lower electrode region has high thermal conductivity for electrical stability, while the upper electrode region has lower thermal conductivity to maintain temperature for detection sensitivity.
2Reliability
If reducing gas barrier protection is added to protect the capacitor from reducing gas, then reliability is improved, but device complexity increases
Solution Approach 1:
The reducing gas barrier layer is merged with the existing electrode and insulator layers to form an integrated protective structure. The barrier layer is positioned between the capacitor and the external environment, combining protection functionality with the existing device architecture rather than adding separate protective components.
Solution Approach 2:
The barrier layer structure serves multiple functions: it provides reducing gas protection, maintains thermal isolation, and structurally integrates with the electrode and insulator layers. This multi-functionality reduces the need for additional separate protective components.
3Measurement precision
If thermal separation properties are enhanced to improve detection sensitivity, then detection precision is improved, but heat dissipation control becomes more difficult
Solution Approach 1:
The thermal conductivity parameter of the upper electrode is changed by selecting Al instead of Pt or Ir, providing a balance between electrical conductivity and thermal isolation. This parameter change allows the upper electrode to maintain temperature for detection sensitivity while still providing necessary electrical functionality.
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 solution effectively protects the pyroelectric detector from reducing gases, reducing oxygen deficit and enhancing thermal separation properties, leading to improved detection sensitivity and reduced thermal capacity, allowing for high detection characteristics.
Implementation Method 1
a first reducing gas barrier layer that protects the capacitor from reducing gas
Implementation Method 2
An infrared detection device utilizes a change (pyroelectric effect or pyroelectronic effect) in the amount of spontaneous polarization of a pyroelectric body according to the light intensity (temperature) of received infrared rays
Implementation Method 3
The heat of the infrared detection element is therefore transmitted to the outside via the lower electrode wiring or the upper electrode wiring
Data Source
AI summary
A pyroelectric detector includes a pyroelectric detection element, a support member, and a support part. The pyroelectric detection element has a capacitor including a first electrode, a second electrode, and a pyroelectric body disposed between the first and second electrodes, and a first reducing gas barrier layer that protects the capacitor from reducing gas. The support member includes first and second sides with the pyroelectric detection element being mounted on the first side and the second side facing a cavity. The support member has a mounting member on which the capacitor is mounted and an arm member linked to the mounting member. The support part supports a portion of the support member. An outer peripheral edge of the first reducing gas barrier layer is disposed between and spaced apart from an outer peripheral edge of the mounting member and an outer peripheral edge of the capacitor in plan view.