Electromechanical Pressure Sensor Using Electrothermal Actuation
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Solution Overview
Problem
Conventional pressure sensors are bulky and their performance depends on resonator geometry and external laser wavelength, limiting miniaturization and sensitivity.
Innovation Solution
An electromechanical pressure sensor with a beam resonator that uses electrothermal heating, where a resonator beam is coupled between fixed anchors and heated by a voltage source, allowing for temperature differential and pressure correlation through a processor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional pressure sensors are used, then they provide accurate pressure estimation, but they are bulky and limit miniaturization
Solution Approach 1:
The patent replaces conventional mechanical pressure sensing elements with a microelectromechanical resonator system that uses electrothermal actuation and optical detection. The resonator beam's resonant frequency changes in response to pressure-induced thermal expansion, allowing miniaturized high-precision pressure sensing without bulky mechanical components
Solution Approach 2:
The patent utilizes changes in the resonator beam's physical parameters (resonant frequency, thermal expansion) in response to pressure variations. By monitoring frequency shifts caused by pressure-induced thermal effects, the system achieves high measurement precision in a miniaturized form factor
2Volume of moving object
If micro-sized resonators are used to reduce size, then miniaturization is achieved, but sensitivity depends on resonator geometry and laser wavelength
Solution Approach 1:
The resonator beam serves dual functions: it is both the structural element and the sensing element. The beam's own resonant properties and thermal response to electrothermal actuation provide the sensing mechanism, eliminating dependence on external laser parameters and resonator geometry for sensitivity
Solution Approach 2:
The resonator structure performs multiple functions simultaneously: mechanical support, thermal actuation, and pressure sensing. This multi-functionality makes the system adaptable and independent of specific resonator geometries or external laser wavelengths, as the same structure handles all functions
3Measurement precision
If external laser heating is used to heat the resonator beam, then pressure sensing is achieved, but the sensor size depends on the laser beam spot-size
Solution Approach 1:
The patent substitutes external optical heating with integrated electrothermal heating using resistive heating elements directly on the resonator beam. This eliminates the need for external laser equipment and their associated beam spot-size constraints, enabling full miniaturization while maintaining pressure sensing capability
Solution Approach 2:
The heating function is merged with the resonator structure by integrating resistive heating elements directly onto the beam. This combination eliminates the need for separate external laser systems, removing the constraint of laser beam spot-size on sensor dimensions
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 sensor achieves high sensitivity and scalability, independent of resonator geometry and external laser wavelength, with improved sensitivity compared to conventional sensors, particularly when driven close to buckling conditions.
Implementation Method 1
a third voltage source coupled to the resonator beam via the first and second fixed anchors, wherein the third voltage source is configured to supply a voltage to the resonator beam that results in a temperature differential between the resonator beam and the first and second fixed anchors
Implementation Method 2
Different ambient pressures cause different frequency shifts in the resonant frequency of the beam due to convective cooling of beam by the air surrounding the beam
Data Source
AI summary
An electromechanical pressure sensor includes an electromechanical resonator having a driving electrode, a sensing electrode, and a beam resonator arranged between the driving and sensing electrodes. The beam resonator includes a resonator beam coupled on a first end to a first fixed anchor and coupled on a second end to a fixed second fixed anchor. The electromechanical resonator also includes a first voltage source coupled to the driving electrode and configured to provide an alternating current to the driving electrode and a second voltage source coupled to the first fixed anchor. The second voltage source provides a DC bias to the resonator beam. The electromechanical resonator further includes a third voltage source coupled to the resonator beam via the first and second fixed anchors. The third voltage source is configured to supply a voltage to the resonator beam that results in a temperature differential between the resonator beam and the first and second fixed anchors. The electromechanical resonator also includes a processor coupled to the sensing electrode and configured to correlate a voltage on the sensing electrode with a pressure value.