Pressure Sensor Adhesive Layer Control via Intermediate Structure
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Solution Overview
Problem
Existing pressure sensors face measurement errors due to thermal cycles causing stress between materials with different coefficients of thermal expansion, leading to temperature hysteresis issues, which are not adequately addressed by controlling the thickness of the adhesive layer.
Innovation Solution
A pressure sensor design featuring an intermediate structure with controlled adhesive thickness, utilizing wedges to maintain the support substrate at a predetermined distance from the base, allowing precise adhesive layer placement and minimizing stress transmission, and incorporating a deformable intermediate structure to absorb thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the adhesive layer is increased to absorb thermal stress, then temperature hysteresis is reduced, but the device complexity increases due to the need for intermediate structures and precise thickness control
Solution Approach 1:
An intermediate structure is introduced between the support substrate and the base, serving as a mediator to precisely control the adhesive layer thickness. This intermediate structure includes positioning elements that ensure uniform spacing, allowing the adhesive layer to effectively absorb thermal stress without requiring complex external control mechanisms.
Solution Approach 2:
The adhesive layer thickness is predetermined and controlled during the assembly process through the intermediate structure's positioning elements. By establishing the correct thickness in advance rather than relying on post-assembly adjustments, the design achieves reliable thermal stress absorption while maintaining manufacturing simplicity.
2Device complexity
If the thickness of the adhesive layer is decreased to simplify the device structure, then device complexity is reduced, but measurement precision deteriorates due to increased stress transmission
Solution Approach 1:
The intermediate structure acts as a mediator that enables the use of a thin adhesive layer while maintaining measurement precision. By providing precise positioning and spacing, it ensures the adhesive layer has the optimal thickness to minimize stress transmission, achieving both structural simplicity and measurement accuracy.
3Ease of manufacture
If the adhesive layer thickness is not precisely controlled to ease manufacturing, then ease of manufacture is improved, but measurement precision deteriorates due to variable stress transmission
Solution Approach 1:
The intermediate structure serves as a manufacturing aid that automatically controls the adhesive layer thickness during assembly. The positioning elements provide mechanical constraints that ensure uniform spacing, eliminating the need for complex thickness control processes while guaranteeing consistent measurement precision.
Solution Approach 2:
The intermediate structure's positioning elements automatically control the adhesive layer thickness during assembly without requiring external measurement or adjustment tools. The structure self-regulates the spacing, making the manufacturing process simpler while ensuring precise and consistent adhesive layer thickness.
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 significantly reduces temperature hysteresis errors, enhancing the precision and accuracy of pressure measurements across varying temperatures.
Implementation Method 1
stress due to a difference between the coefficients of thermal expansion of the two materials
Implementation Method 2
adhesive layer comprising a base material and microbeads... having properties of flexibility when subjected to temperature variations
Data Source
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AI summary
The invention relates to a pressure sensor including: a sensitive element including a mounting substrate, said mounting substrate including a top surface and a bottom surface, the sensitive element also including a deformable diaphragm that is connected to the top surface of the mounting substrate; a housing, in which the sensitive element is placed, said housing including a base; an intermediate structure placed between the base of the housing and the mounting substrate, said intermediate structure including a base, the base including a top surface and a bottom surface that is connected to the base of the housing, said intermediate structure being configured such as to keep the mounting substrate at a predetermined distance from the top surface of the intermediate structure; and an adhesive layer extending onto the top surface of the intermediate structure. Said adhesive layer has a thickness controlled by the predetermined distance at which the mounting substrate is kept from the top surface of the intermediate structure. The invention also relates to a method for making such a pressure sensor.