Microelectromechanical Sensor Deposit Detection via Mechanical Excitation
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Solution Overview
Problem
Existing sensor systems face challenges in accurately and reliably detecting deposits on sensor structures, which can impair the measurement of environmental variables such as pressure.
Innovation Solution
A method for sensor state detection that uses a microelectromechanical sensor structure with a converter unit to convert deflection into measurable variables, and employs mechanical excitation to detect deposits by evaluating changes in the measured variable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate liquid detection units or additional electrodes are added to detect deposits, then deposit detection capability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The existing sensor structure is made multi-functional by enabling it to perform both its primary measurement function and deposit detection function. The sensor structure responds to both environmental variables (pressure, humidity, temperature) and deposit presence through its mechanical deflection, eliminating the need for separate detection units.
Solution Approach 2:
The sensor structure serves itself by using its own deflection response to detect deposits. The same structural elements that measure environmental variables also detect deposit presence through changes in their mechanical response to excitation signals, making the system self-diagnostic without additional components.
2Reliability
If complex deposit detection methods are implemented, then deposit detection reliability is improved, but ease of manufacture and implementation deteriorates
Solution Approach 1:
The system uses feedback from the sensor structure's response to excitation signals to detect deposits. By comparing the actual response (including phase, frequency, amplitude) against expected responses, the system reliably detects deposit presence without complex implementation.
Solution Approach 2:
The method applies mechanical excitation (vibration or acoustic oscillation) to the sensor structure and analyzes its response to detect deposits. This approach provides reliable detection through well-established vibration analysis techniques that are straightforward to implement.
3Adaptability or versatility
If the sensor structure is exposed to ambient medium for measurement, then environmental variable measurement capability is improved, but susceptibility to deposit accumulation increases
Solution Approach 1:
The deposit accumulation, which is harmful to measurement accuracy, is converted into a useful detection signal. The presence of deposits modifies the sensor structure's mechanical response to excitation, and this modification is detected and used to identify deposit presence, turning a problem into a diagnostic opportunity.
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 method allows for more reliable and accurate detection of deposits, enhancing the reliability and accuracy of environmental variable measurements, and is cost-effective and easier to implement.
Implementation Method 1
The sensor membrane can be deflected depending on a differential pressure between the upper side and underside of the sensor membrane
Implementation Method 2
The environmental sensor can be a pressure sensor. The pressure sensor can be a capacitive, piezoresistive or piezoelectric pressure sensor.
Implementation Method 3
The environmental sensor can be a pressure sensor. The pressure sensor can be a capacitive, piezoresistive or piezoelectric pressure sensor.
Implementation Method 4
The environmental sensor can be a pressure sensor. The pressure sensor can be a capacitive, piezoresistive or piezoelectric pressure sensor.
Data Source
AI summary
A method for sensor state detection of an environmental sensor for measuring at least one physical environmental variable of an ambient medium. The method includes providing the environmental sensor including a micromechanical sensor structure that can be deflected depending on the environmental variable, is exposed to the ambient medium and on which at least one interfering deposit entering via the ambient medium can be deposited and further comprising a converter unit for providing a measured variable depending on the deflection of the sensor structure, detecting an existing deposit of this type on the sensor structure by means of an excitation deviating from the environmental variable, wherein the excitation is a mechanical excitation acting externally on the environmental sensor, via which the deposit moves with an excitation movement on the sensor structure. An environmental sensor system and a mobile consumer device are also described.