Membrane Sensor Z-Stacked Acceleration Compensation
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Solution Overview
Problem
Micromechanical pressure sensors are affected by acceleration forces and inertial forces, leading to reduced accuracy and sensitivity, as existing methods to enhance robustness, such as using gels, can compromise sensor performance.
Innovation Solution
A stacked arrangement of pressure and acceleration sensors, where the pressure sensor and acceleration sensor are aligned in the z-direction, allowing direct detection and compensation of acceleration influences on the membrane, enabling separate optimization of manufacturing processes and signal quality for each sensor type.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gel is used to protect the pressure sensor from corrosion and adsorbate deposition, then media robustness is improved, but measurement precision deteriorates due to adverse effects on pressure detection accuracy
Solution Approach 1:
The patent introduces an acceleration sensor as an intermediary component that indirectly compensates for the adverse effects of the gel on pressure measurement. Instead of modifying the gel or pressure sensor directly, the system uses the acceleration sensor to detect and compensate for the interference forces, thereby maintaining both media robustness and measurement precision.
Solution Approach 2:
The patent implements a feedback mechanism where the acceleration sensor continuously monitors acceleration forces and the evaluation circuit uses this information to compensate for g-sensitivity effects on the pressure measurement. This closed-loop feedback system ensures that pressure detection accuracy is maintained despite the presence of the gel.
2Volume of moving object
If the pressure sensor and acceleration sensor are integrated at chip level, then device compactness is improved, but manufacturing complexity increases due to conflicting process requirements
Solution Approach 1:
The patent merges the pressure sensor and acceleration sensor into a stacked arrangement where they share common structural elements, such as the first substrate and bonding wires. This merging approach reduces overall device volume while allowing each sensor to be manufactured using its own optimized process, thereby avoiding the complexity of fully integrated chip-level manufacturing.
Solution Approach 2:
The patent transitions from a planar side-by-side arrangement to a three-dimensional stacked configuration. By arranging the sensors in the vertical z-direction rather than horizontally, the system achieves compactness without requiring complex lateral integration processes, thus simplifying manufacturing while reducing volume.
3Strength
If the membrane thickness is increased to improve pressure sensor robustness, then strength is improved, but measurement precision deteriorates due to reduced membrane sensitivity
Solution Approach 1:
The acceleration sensor serves as an intermediary that compensates for the reduced sensitivity caused by using a thicker membrane. By detecting and compensating for acceleration-induced deflections, the system maintains measurement precision even with a more robust, thicker membrane structure.
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 configuration effectively compensates for g-sensitivity and other acceleration-induced interference, improving the accuracy and robustness of pressure detection while maintaining cost-effectiveness and simplicity in production.
Implementation Method 1
The pressure sensor is configured to generate, for example capacitively or piezoresistively, a first sensor signal depending on a deflection of the membrane
Implementation Method 2
The pressure sensor is configured to generate, for example capacitively or piezoresistively, a first sensor signal depending on a deflection of the membrane
Implementation Method 3
The acceleration sensor has a MEMS functional structure and is configured to generate a second sensor signal depending on an acceleration acting on the MEMS functional structure
Data Source
AI summary
A membrane sensor. The membrane sensor includes: a pressure sensor configured to generate a first sensor signal depending on a deflection of a pressure-loadable membrane; an acceleration sensor configured to generate a second sensor signal depending on an acceleration acting on a MEMS functional structure; and an evaluation circuit configured to compensate for a dependence of the first sensor signal on an acceleration force, in particular weight force, acting on the membrane, based on the second sensor signal. The pressure sensor and the acceleration sensor are stacked one above the other in a z direction. A method for generating a compensated sensor signal using such a membrane sensor is also described.