Infrared Sensor Reference Element Air Gap Design
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Solution Overview
Problem
Current infrared sensor reference elements either require costly covering processes or direct contact with substrates, leading to uncontrollable uniformity issues due to height differences, which affect the accuracy of temperature measurement.
Innovation Solution
A reference element design featuring a substrate with a sacrificial layer, supporting structure, fence structure, and infrared sensing structure, where the sacrificial layer is embedded with the supporting and fence structures, and an air gap is created between them, allowing for precise thermal contact and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the reference element is implemented as a sensing structure covered to refrain from infrared light irradiation, then the resistance can present the substrate temperature, but the manufacturing process becomes more costly and challenging
Solution Approach 1:
The reference element is segmented into distinct functional components: a reference sensing structure for temperature sensing, a supporting structure for mechanical support, and a fence structure for infrared light blocking. This segmentation allows each component to be optimized independently while simplifying the overall manufacturing process compared to a fully covered sensing structure
Solution Approach 2:
The fence structure acts as an intermediary element that selectively blocks infrared light from reaching the reference sensing structure while allowing other wavelengths to pass through. This intermediary approach achieves temperature measurement without requiring complete covering of the sensing structure, reducing manufacturing complexity
2Stability of the object's composition
If the reference element is implemented as a sensing structure directly contacted with the substrate without an air gap, then thermal equilibrium with the substrate is achieved, but the height difference between the reference element and the sensing element causes difference in electrical signal paths and makes overall uniformity uncontrollable
Solution Approach 1:
The patent introduces a vertical air gap dimension between the reference sensing structure and the substrate, separating the thermal contact function (achieved through the supporting structure) from the electrical signal path function. This dimensional separation allows thermal equilibrium to be maintained while keeping the sensing structures at the same height level for uniform electrical paths
Solution Approach 2:
The thermal contact function is extracted from the sensing structure itself and assigned to a dedicated supporting structure. This extraction allows the sensing structure to be elevated on the air gap, maintaining electrical path uniformity while the supporting structure provides the necessary thermal contact with the substrate through the sacrificial layer
3Measurement precision
If the reference element uses a covering process to block infrared light, then the substrate temperature can be measured, but additional manufacturing steps increase cost and difficulty
Solution Approach 1:
The fence structure is designed as a simple, disposable infrared-blocking element that can be easily manufactured and integrated. Rather than requiring complex covering processes on the entire sensing structure, the fence structure provides targeted infrared blocking with minimal manufacturing steps, reducing both cost and device complexity
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 enhances the accuracy of temperature measurement by maintaining uniformity and stability, reducing electrical deviations and improving production yield rates while allowing for precise thermal contact between the reference element and the substrate.
Implementation Method 1
An infrared sensing element can absorb infrared emitted from objects and transform the energy of infrared light into heat energy, and the heat energy can make the temperature of the sensing element rise
Implementation Method 2
the heat energy can make the temperature of the sensing element rise so as to change the resistance of the sensing material
Implementation Method 3
there is an air gap between the fence structure and the supporting structure
Data Source
AI summary
A reference element of an infrared sensor includes a substrate, a sacrificial layer, a supporting structure, a fence structure and an infrared sensing structure. The sacrificial layer is disposed on the substrate. The supporting structure is disposed on the substrate wherein the top surface of the supporting structure is coplanar with the top surface of the sacrificial layer. The fence structure is disposed on the substrate and surrounds the sacrificial layer wherein the top surface of the fence structure is coplanar with the top surface of the sacrificial layer, and there is an air gap between the fence structure and the supporting structure. The infrared sensing structure is disposed on the sacrificial layer, the supporting structure and the fence structure, and the infrared sensing structure has an opening corresponding to the air gap.