MEMS Pressure Sensor Deflection Correction
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Solution Overview
Problem
Microelectromechanical pressure sensors experience measurement deviations due to the weight of protective media, which exert pressure and distort pressure measurement values, especially when positioned relative to Earth's gravitational force.
Innovation Solution
A microelectromechanical pressure sensor design with a deflectable pressure sensor element and a deflection measuring element, where the receiving space is filled with a protective medium, allowing for the measurement and correction of pressure values by calibrating the deflection relative to the base structure, using a decoupling plate and strain gauges for precise measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the receiving space is filled with protective medium to cover and protect the pressure sensor element, then the pressure sensor element is protected from environmental influences, but the protective medium exerts pressure on the pressure sensor element due to its mass, distorting pressure measurement values
Solution Approach 1:
A decoupling plate is introduced as an intermediary component between the pressure sensor element and the protective medium. The decoupling plate is resiliently connected to the base structure via a suspension element, allowing it to deflect under the weight of the protective medium while keeping the pressure sensor element isolated from direct pressure exposure. This mediator absorbs the harmful gravitational pressure while maintaining the protective coverage.
Solution Approach 2:
The system is segmented into distinct functional components: the base structure, the decoupling plate, the pressure sensor element, and the suspension element. By separating the pressure sensor element from the direct load path of the protective medium's weight, the measurement function is isolated from the protective function, allowing both to coexist without interference.
2Measurement precision
If the pressure sensor element is made deflectable relative to the base structure to enable correction measurements, then the relative deflection can be measured to correct pressure values, but the pressure sensor element becomes more sensitive to external pressure influences
Solution Approach 1:
The decoupling plate serves as a mediator that allows controlled deflection for measurement purposes while protecting the pressure sensor element from harmful external pressures. The suspension element provides the necessary compliance for deflection measurement while filtering out high-frequency vibrations and shock loads through its elastic properties.
Solution Approach 2:
The pressure sensor element and decoupling plate are designed with dynamic characteristics that allow them to deflect in response to gravitational changes for correction measurements, while the suspension element's mechanical properties filter out harmful high-frequency vibrations and shock loads, converting them into manageable elastic deformations.
3Object-affected harmful factors
If a decoupling plate with suspension element is used to reduce harmful pressure transmission, then vibrations and stresses are decoupled from the pressure sensor element, but the device complexity increases
Solution Approach 1:
The suspension element is designed as a flexible, thin-walled structure that provides vibration isolation and stress decoupling through its elastic properties. This flexible connection allows the system to achieve complex vibration filtering functionality with minimal material and structural complexity, avoiding the need for heavy dampers or complex isolation mechanisms.
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 enables precise correction of pressure measurement values by accounting for the pressure exerted by the protective medium, ensuring accurate readings despite environmental influences and gravitational effects.
Implementation Method 1
the protective medium exerts pressure on the pressure sensor element due to the mass of the protective medium. This pressure of the protective medium can distort the pressure measurement values
Implementation Method 2
the pressure sensor element is arranged so as to be deflectable relative to the base structure. By measuring the relative deflection of the pressure sensor element relative to the base structure
Implementation Method 3
the deflection measuring element can be calibrated to known pressures so that corresponding pressure values exerted on the pressure sensor element can be ascertained on the basis of the measured relative deflection
Data Source
AI summary
A microelectromechanical pressure sensor having a housing unit, a base structure, a pressure sensor element, and a deflection measuring element. The housing unit defines a receiving space. The base structure, the pressure sensor element, and the deflection measuring element are arranged in the receiving space. The receiving space is filled with a protective medium which covers the pressure sensor element. The pressure sensor element is arranged so as to be deflectable relative to the base structure. The deflection measuring element is configured to determine a relative deflection of the pressure sensor element relative to the base structure. A method for correcting pressure measurement values of a microelectromechanical pressure sensor is also described.