Dual Diaphragm Pressure Sensor Temperature Acceleration Compensation
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Solution Overview
Problem
Conventional differential pressure sensors face inaccuracies due to external forces like heat, vibration, and acceleration, which are not compensated for, leading to non-pressure effects influencing measurements.
Innovation Solution
A dual diaphragm compensated differential pressure sensor with physically and/or electrically isolated diaphragms, where one diaphragm is exposed to pressure and the other is in a hermetically sealed chamber, allowing for subtraction of non-pressure effects from the signal, using piezoresistive elements to generate signals proportional to pressure and non-pressure effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single diaphragm pressure sensor is used, then the device complexity is low, but measurement precision deteriorates due to uncompensated non-pressure effects
Solution Approach 1:
The sensor is divided into two separate diaphragms: a first diaphragm exposed to both pressure and non-pressure effects, and a second diaphragm exposed only to non-pressure effects through a sealed cavity. This segmentation allows independent measurement of pressure effects and non-pressure effects, which can then be differentiated to improve measurement precision.
Solution Approach 2:
A sealed cavity acts as an intermediary between the two diaphragms, allowing the second diaphragm to be exposed to non-pressure effects (heat, vibration, acceleration) while isolating it from pressure effects. This intermediary structure enables the second diaphragm to serve as a reference for non-pressure effect compensation.
2Measurement precision
If a second sealed diaphragm is added for compensation, then measurement precision improves, but device complexity increases
Solution Approach 1:
Both diaphragms are integrated onto a single chip substrate, sharing common structural support and packaging. This merging approach reduces the overall device complexity compared to using two separate sensor packages, while still maintaining the functional separation needed for compensation.
3Measurement precision
If piezoresistors are mounted on both diaphragms, then measurement precision improves through signal subtraction, but manufacturing precision requirements increase
Solution Approach 1:
Both diaphragms are fabricated from the same silicon substrate material using identical piezoresistive sensor technology. This homogeneity ensures that both diaphragms respond identically to non-pressure effects, allowing accurate compensation through signal subtraction while simplifying manufacturing processes.
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 provides accurate pressure measurements by isolating non-pressure effects, enhancing the sensor's accuracy and reliability, especially in harsh environments like jet engines.
Implementation Method 1
A piezo element can be a piezoresistive element or a piezoelectric element. A piezoresistive element is an element that produces a change in resistance in response to an applied force.
Implementation Method 2
When pressure is applied to the diaphragm, the diaphragm deflects. This deflection, in turn, places the piezo elements mounted thereon under compression or tension
Data Source
AI summary
A dual diaphragm pressure transducer, or sensor, with compensation for non-pressure effects is disclosed. The pressure sensor can include two pressure transducers located on separate portions of a chip. The first pressure transducer can be a differential pressure transducer, which produces a signal proportional to one or more applied pressures and includes other non-pressure effects. The second pressure transducer can be sealed in a hermetic chamber and thus can produce a signal proportional only to non-pressure effects. The signals can be combined to produce a signal proportional to the applied pressures with no non-pressure effects. The first and second pressure transducers can be physically and/or electrically isolated to improve sealing between the two pressure transducers and prevent pressure leaks therebetween.