Capacitive Pressure Sensor Dual-Range Detection Segmentation
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Solution Overview
Problem
Conventional pressure sensors are limited to a specific range and struggle to detect high pressure peaks, which are relevant in applications like in-ear headphones and dive computers, where pressures exceed typical ambient levels.
Innovation Solution
A capacitive pressure sensor element with two measuring capacitors, one for a primary range and another as a reference, allowing detection of pressures in two distinct ranges by varying capacitance, with the second capacitor taking over in higher ranges where the first capacitor's signal is no longer usable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pressure sensor is designed for a predetermined pressure range with high sensitivity, then small pressure fluctuations can be detected accurately, but high pressure peaks cannot be detected
Solution Approach 1:
The pressure sensor is divided into two functional parts: a first measuring capacitor for detecting small pressure changes in a first pressure range, and a second measuring capacitor for detecting high pressure peaks in a second pressure range. Each capacitor is optimized for its specific range, allowing the sensor to accurately measure both small fluctuations and high pressure peaks without compromise.
Solution Approach 2:
The pressure sensor system is designed to perform multiple functions by incorporating two measuring capacitors that can operate in different pressure ranges. The evaluation circuit automatically selects which capacitor to use based on the detected pressure level, enabling the sensor to universally handle both typical ambient pressure changes and extreme high pressure peaks.
2Measurement precision
If the second electrode rests on the first electrode or movement is restricted by spacers, then the first capacitor cannot detect further pressure changes, but the sensor needs to continue detecting in higher pressure ranges
Solution Approach 1:
The second measuring capacitor acts as an intermediary mechanism that takes over the detection function when the first capacitor reaches its limit. When the second electrode contacts the first electrode or spacers restrict movement, the evaluation circuit switches to using the second measuring capacitor, which still has available detection range, thereby extending the overall pressure measurement capability.
Solution Approach 2:
When the first measuring capacitor reaches its detection limit (electrode contact or spacer restriction), its function is effectively discarded for higher pressure measurements. The system recovers by activating the second measuring capacitor, which was previously in a standby or reference state, to continue the pressure detection task in the higher pressure range.
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
Enables accurate detection of pressures across two ranges, enhancing sensitivity in the primary range while maintaining functionality in higher pressures by switching to a secondary sensor signal, ensuring continuous and reliable pressure measurement.
Implementation Method 1
a deflection of the membrane and thus the capacitance between the first and second electrodes, which varies due to the change in distance, can subsequently be detected as a measure of the pressure applied to the membrane
Implementation Method 2
a second measuring capacitor is provided in the pressure sensor element according to an example embodiment of the present invention, which is used as a reference capacitor in the first pressure range, which is characterized by the fact that the applied pressure and the movement of the membrane do not result in a change in the capacitance of the second measuring capacitor
Data Source
AI summary
A capacitive pressure sensor element. The capacitive pressure sensor element includes a first measuring capacitor, which generates a first sensor signal in a first pressure range, and a second measuring capacitor, which is used as a reference capacitor in the first pressure range and which generates a second pressure-based sensor signal in the second pressure range. A pressure sensor system which has at least two of the pressure sensor elements, and methods for producing the pressure sensor the pressure sensor system are also described.