Dual-Membrane Pressure Sensor for Wide-Range Linear Detection
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Solution Overview
Problem
Existing micromechanical pressure sensors face challenges in accurately detecting pressure values across different ranges due to non-linear dependencies and membrane deflection limitations, which can lead to inaccuracies and the need for additional stop elements to prevent membrane damage.
Innovation Solution
A micromechanical pressure sensor design utilizing two membranes of different types, each designed for specific pressure ranges, with varying lateral extensions and connected via pressure equalization channels, allowing for accurate detection of pressure values through a Wheatstone bridge configuration, thereby minimizing non-linear dependencies and enhancing sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single membrane is used for pressure detection, then the device complexity is low, but the measurement precision deteriorates due to non-linear dependencies and limited pressure ranges
Solution Approach 1:
The pressure sensor is segmented into multiple membranes (first membrane for first pressure range, second membrane for second pressure range) that each operate optimally within their respective ranges. This segmentation allows linear detection across different pressure ranges while maintaining overall measurement precision, resolving the contradiction between using a single simple membrane and achieving high precision across multiple pressure ranges.
2Measurement precision
If the membrane bending is allowed to extend to maximum range, then the sensitivity is high, but the reliability deteriorates due to non-linear dependencies and potential membrane damage
Solution Approach 1:
The pressure detection range is segmented between two membranes with different size specifications. The first membrane handles the first pressure range with high sensitivity, while the second membrane handles the second pressure range. This segmentation prevents either membrane from operating beyond its optimal linear range, maintaining both sensitivity and reliability.
Solution Approach 2:
The patent changes the size parameters of the membranes to create two distinct membrane types with different bending characteristics. By adjusting membrane dimensions, each membrane is optimized for its specific pressure range, ensuring linear operation and preventing damage while maintaining high sensitivity within each range.
3Reliability
If stop elements are added to limit membrane bending, then the reliability is improved, but the device complexity increases and measurement precision deteriorates due to interference with membrane movement
Solution Approach 1:
Instead of adding stop elements to a single membrane system, the patent segments the pressure detection into two separate membranes, each with its own optimal operating range. This eliminates the need for stop elements that would interfere with membrane movement, as each membrane naturally operates within its linear range without requiring mechanical limits.
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 dual membrane design enables precise and continuous pressure detection across overlapping or non-overlapping ranges, stabilizing sensor signals against temperature and outgassing effects, and ensuring accurate pressure measurement with reduced measurement errors.
Implementation Method 1
a first pressure sensor variable in a first pressure range is detected by means of bending of the first membrane
Implementation Method 2
at least one first cavern of a first membrane type is connected directly or indirectly to at least one second cavern of a second membrane type
Implementation Method 3
an insulating layer can be provided on the cavern floor and/or on the underside of the membrane in order to electrically separate the movable upper electrode in the membrane from the static/stationary lower electrode on the cavern floor in a pressure sensor with capacitive measurement value detection
Data Source
AI summary
A micromechanical pressure sensor. The sensor has at least one membrane of a first membrane type, using which a first pressure sensor variable in a first pressure range can be detected. To enable the bending of the membrane, the first membrane is formed above a first cavern in/on a substrate including semiconducting material. In/on this substrate, at least one second membrane of a second membrane type is formed above a second cavern, using which a second pressure sensor variable in a second pressure range can be detected. A bending behavior of each of the membranes generate pressure sensor variables that are ascertained within different pressure ranges. The different pressure ranges can partially overlap. The different bending behavior of the membranes of the different membrane types is caused by a different design of the geometric expansions of the first and second membrane in at least one lateral direction.