Pressure Sensor with Oscillating Counter-Surface for Drift Reduction
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Solution Overview
Problem
Existing pressure sensors, particularly in vacuum applications, suffer from significant thermal and temporal drift, leading to resolution issues and increased complexity, making them costly and unreliable.
Innovation Solution
A pressure measurement device featuring a pressure sensor with an active sensor surface and a counter-surface that oscillates or changes temperature, arranged within a hollow body with side walls, utilizing AC signal amplification to minimize drift and enhance resolution, allowing for efficient pressure detection through fluctuating volume or temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional pressure sensors (membrane, piezoelectric, piezoresistive) are used, then pressure measurement is achieved, but thermal and temporal drift occurs leading to reduced measurement precision
Solution Approach 1:
The patent applies periodic action by oscillating the counter-surface at a specific frequency (e.g., 50 Hz) to generate AC signals that are amplified and processed. This periodic oscillation creates a dynamic measurement mode that eliminates DC offset drift, as the AC coupling in the amplifier chain blocks direct current components while passing the AC measurement signals, thereby resolving the zero point stability issue.
Solution Approach 2:
The patent introduces a hollow body with side walls as an intermediary structure between the sensor surface and counter-surface. This hollow body acts as a mediator that defines a controlled volume for pressure measurement, isolating the measurement chamber from external environmental influences that cause thermal drift, while still allowing pressure transmission through openings.
2Measurement precision
If high resolution pressure measurement is required, then measurement precision improves, but device complexity increases due to additional components needed to compensate for drift
Solution Approach 1:
The periodic oscillation of the counter-surface simplifies the device by converting DC measurement problems into AC measurement problems. The AC signal amplifier with AC coupling inherently provides drift rejection without requiring complex temperature compensation circuits or multiple sensors, achieving high resolution through dynamic measurement rather than complex static compensation.
Solution Approach 2:
The patent employs mechanical vibration by oscillating the counter-surface to generate dynamic pressure signals on the sensor membrane. This vibration-based approach converts static pressure measurement into dynamic AC signal measurement, which can be amplified with high gain while rejecting DC offsets, thereby achieving high resolution without complex additional components.
3Measurement precision
If vacuum pressure sensing is implemented with exposed membranes, then pressure detection capability is achieved, but reliability decreases due to susceptibility to failure
Solution Approach 1:
The patent uses a hollow body with side walls that encloses the sensor membrane, protecting it from direct exposure to the vacuum environment. The hollow body acts as a protective shell that allows pressure transmission through openings while shielding the fragile membrane from mechanical damage, contamination, and outgassing effects, thereby improving reliability without sacrificing vacuum detection capability.
4Reliability
If AC signal amplification is used to reduce drift, then measurement stability improves, but manufacturing precision requirements increase
Solution Approach 1:
The hollow body serves as an intermediary structure that provides mechanical support and defines the measurement volume. Its primary function is structural rather than precision optical or mechanical, allowing for relatively relaxed manufacturing tolerances compared to interferometric or capacitive sensors. The AC amplification scheme further reduces sensitivity to small dimensional variations, making the system robust to manufacturing imperfections.
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 solution significantly reduces thermal and temporal drift, enabling high-resolution pressure measurements with reduced offset drift, allowing for more accurate and cost-effective vacuum pressure sensing.
Implementation Method 1
a vibrating and/or temperature-changing counter-surface being arranged opposite the at least one sensor surface
Implementation Method 2
at least one AC signal amplifier is provided
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a device for measuring pressure with at least one pressure sensor having at least one active sensor surface, in which an oscillating and/or temperature-varying counter-surface is arranged opposite the at least one sensor surface, in which the sensor surface and the counter-surface are arranged in a hollow body, the hollow body having at least one opening, and in which at least one alternating signal amplifier is provided. (Fig. 1).