Infrared Sensor Thermal Insulation via Segmented Support Posts
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Solution Overview
Problem
Infrared sensors with pyroelectric substrates bonded to Si substrates suffer from inadequate thermal insulation, leading to insufficient thermoelectric conversion efficiency and responsiveness due to direct contact between the substrates.
Innovation Solution
An infrared sensor design featuring a first substrate made of thermoelectric material with a sensing electrode, supported by posts that maintain spacing from a second substrate, providing thermal insulation and improved thermoelectric conversion efficiency, along with a method involving substrate bonding, thickness reduction, and post formation for enhanced insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the pyroelectric substrate is bonded to the Si substrate, then the thickness of the pyroelectric substrate can be reduced and packing density can be increased, but thermal insulation becomes insufficient and thermoelectric conversion efficiency deteriorates
Solution Approach 1:
The patent divides the substrate support structure into multiple discrete posts instead of continuous contact. The pyroelectric substrate is supported at multiple discrete locations by insulating posts, creating segmented contact points that maintain mechanical support while minimizing thermal conduction paths. This segmentation allows the substrate to be thin for high packing density while preventing heat loss to the Si substrate.
Solution Approach 2:
The patent introduces an intermediary insulating layer or posts between the pyroelectric substrate and the Si substrate. This intermediary structure provides mechanical support and positioning while blocking thermal conduction. The insulating posts act as mediators that maintain the necessary spacing to prevent heat transfer while allowing the thin substrate structure to function effectively.
2Device complexity
If the pyroelectric substrate is in direct contact with the Si substrate, then structural support is simplified, but thermal conduction increases and responsiveness deteriorates
Solution Approach 1:
The support structure is segmented into multiple discrete insulating posts rather than continuous contact. This segmentation maintains structural support while creating thermal barriers at each contact point, preventing heat conduction to the Si substrate and improving the thermal response speed of the pyroelectric substrate.
Solution Approach 2:
Insulating posts or layers are introduced as intermediary elements between the pyroelectric substrate and Si substrate. These intermediaries provide the necessary mechanical support and positioning while blocking thermal conduction paths, thereby improving responsiveness without significantly increasing overall device complexity.
3Quantity of substance
If the thickness of the pyroelectric substrate is reduced, then packing density of infrared-sensing portions increases, but thermal insulation becomes insufficient
Solution Approach 1:
The patent uses discrete insulating posts to segment the thermal contact points between the thin pyroelectric substrate and the Si substrate. This segmentation approach allows the substrate to be reduced in thickness for high packing density while maintaining thermal insulation through the interrupted contact structure.
Solution Approach 2:
Insulating posts serve as intermediary elements that enable the thin substrate structure to achieve high packing density while preventing thermal conduction to the Si substrate. The intermediaries decouple the mechanical support function from thermal conduction, allowing independent optimization of both parameters.
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 design achieves improved thermal insulation and responsiveness with increased packing density and reduced crosstalk, enhancing thermoelectric conversion efficiency and sensitivity while preventing thermal conduction issues.
Implementation Method 1
a first substrate made of a thermoelectric conversion material, a sensing electrode arranged on at least one main surface of the first substrate, the sensing electrode sensing infrared rays incident on the first substrate
Implementation Method 2
a plurality of posts arranged to connect the first substrate and the second substrate and support the first substrate and the second substrate while the first substrate and the second substrate are spaced apart from one another
Data Source
AI summary
An infrared sensor includes a first substrate made of a thermoelectric conversion material and a second substrate. The first substrate is supported by posts made of an electrode material while being spaced apart from the second substrate. A sensing electrode and lead portions connected thereto are provided on the first substrate. The sensing electrode and the lead portions are covered with an infrared-absorbing film. The posts are connected to the lead portions, and external terminal connection electrodes are connected to the posts.