Sensor Flexible Portion Mechanical Decoupling Soldering
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Solution Overview
Problem
Microelectromechanical sensor elements (MEMS) can produce incorrect electrical signals due to thermomechanical stress or bending, which are not intended to be detected, leading to inaccurate readings of the physical variables they are meant to measure.
Innovation Solution
A sensor design with a support structure featuring a cavity that forms a flexible portion, allowing mechanical decoupling of the sensor element from disturbance variables, using a sacrificial material to stabilize the flexible area during soldering and a damping material to absorb vibrations, enabling reliable detection of physical variables while preventing direct force transmission to the sensor element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the sensor element is rigidly connected to the support structure, then mechanical stability is improved, but disturbance variables such as thermomechanical stress and bending directly affect the sensor element causing incorrect electrical signals
Solution Approach 1:
The support structure is segmented into a rigid portion and a flexible portion, creating a mechanical decoupling between the sensor element and the contact surfaces. This segmentation allows the rigid portion to provide stability while the flexible portion absorbs disturbance variables, preventing them from reaching the sensor element.
Solution Approach 2:
The flexible portion acts as a compliant interface between the rigid support structure and the sensor element. This flexible element mechanically decouples the sensor element from disturbance variables while maintaining electrical connectivity, allowing the sensor to accurately detect physical variables without being affected by thermomechanical stress or bending.
2Measurement precision
If the flexible portion is made highly compliant to absorb all disturbances, then measurement precision is improved, but mechanical strength and structural integrity deteriorate
Solution Approach 1:
Different portions of the support structure have different mechanical properties: the rigid portion provides structural strength and stability, while the flexible portion provides compliance for disturbance absorption. This local differentiation of material properties allows the structure to simultaneously achieve both strength and measurement precision.
3Ease of manufacture
If the contact surface is directly connected to the sensor element, then ease of manufacture is improved, but the sensor element becomes susceptible to disturbance variables causing incorrect readings
Solution Approach 1:
The support structure is divided into distinct rigid and flexible portions, creating a mechanical decoupling pathway. This segmentation maintains manufacturing simplicity by using a single integrated structure while achieving reliable signal accuracy through the flexible portion that blocks disturbance variables from reaching the sensor element.
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 mechanical decoupling effectively reduces the impact of disturbance variables on the sensor, ensuring accurate electrical signal mapping of the intended physical variables, thereby enhancing the reliability and precision of the sensor's measurements without the need for post-soldering calibration.
Implementation Method 1
the flexible portion being formed to surround the contact surface at least in one spatial direction to be mechanically at least partially decoupled from the sensor element
Implementation Method 2
A damping material can be arranged in the cavity, which is designed to absorb vibrations of the flexible partial area in the at least one spatial direction
Implementation Method 3
A removable sacrificial material can be arranged in the cavity, which is designed to fix the flexible partial area in the spatial direction during the production of the soldered connection
Implementation Method 4
The contact surface can be a metallic or metallized surface that is designed to be wetted by a solder
Data Source
Figure 1~3
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Figure 7~9
AI summary
The sensor (100) has a carrier structure (102) provided with an integrated electronic sense element (104) and comprising a cavity (200) for forming a flexible portion (202) to the structure. The flexible portion is formed with a contact surface (106) for manufacturing a soldered joint such that the surface is partially and mechanically decoupled from the sensor element along spatial direction (204). A removable victim material is arranged in the cavity and adapted in the portion during manufacture of the solder joint and/or the sensor to fix the material in the spatial direction. The victim material is designed as a transport lock. An independent claim is also included for a method for manufacturing a solder connection between a sensor and a circuit board.