Flexible Capacitive Sensor for Simultaneous Pressure and Humidity Measurement
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Solution Overview
Problem
Existing sensors fail to accurately measure pressure and humidity simultaneously with high precision and flexibility, particularly in dynamic environments like vehicle seats, where weight and occupancy type need to be determined.
Innovation Solution
A capacitive sensor apparatus with a flexible support material, featuring electrodes and a dielectric layer, combined with a moisture-permeable layer that changes capacitance in response to humidity, integrated with a processing unit to measure and store changes, allowing for simultaneous pressure and humidity sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a capacitive sensor with moisture-permeable layer is used to measure humidity, then measurement precision of humidity is improved, but device complexity increases due to additional layers and processing requirements
Solution Approach 1:
The patent combines humidity sensing and pressure sensing functions into a single capacitive sensor structure. The sensor integrates a moisture-permeable layer, dielectric layer, and electrode assembly that can simultaneously detect both humidity (through capacitance changes from moisture absorption) and pressure (through capacitance changes from electrode deformation), thereby improving measurement precision while reducing device complexity compared to using separate sensors.
Solution Approach 2:
The capacitive sensor is designed with multi-functionality to perform both humidity measurement and pressure measurement using the same structural components. The moisture-permeable layer enables humidity detection, while the flexible support material and electrode arrangement enable pressure detection, allowing one device to serve multiple measurement purposes without requiring additional specialized components.
2Adaptability or versatility
If a flexible support material is used to enable bending and dynamic sensing, then adaptability to dynamic environments is improved, but manufacturing precision becomes more difficult to maintain
Solution Approach 1:
The patent employs a flexible support material as the base structure for the capacitive sensor, allowing the entire sensor assembly to bend and conform to dynamic surfaces such as vehicle seats. This flexible substrate maintains the structural integrity of the layered capacitor construction while enabling adaptation to changing geometries, thereby improving adaptability to dynamic environments despite the challenges in manufacturing precision.
3Device complexity
If multiple sensor functions are integrated into a single apparatus, then device complexity is reduced, but measurement precision of individual parameters may deteriorate
Solution Approach 1:
The patent merges humidity sensing and pressure sensing into a single capacitive sensor apparatus, reducing the number of separate components needed. The integrated design uses shared elements (electrodes, dielectric layer, flexible support) that function for both measurement types, thereby simplifying the overall device while maintaining measurement precision through careful design of the capacitor structure and signal processing.
Solution Approach 2:
The capacitive sensor is designed with universal functionality to accurately measure both humidity and pressure simultaneously. The moisture-permeable layer and flexible support material work together to enable dual sensing capabilities, allowing the same structural components to serve multiple measurement purposes without compromising the precision of individual parameter detection.
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 determination of weight and occupancy type by combining relative humidity and pressure measurements, providing warnings for seat overload or excessive sweating, and potentially influencing airbag deployment timing for user safety.
Implementation Method 1
a capacitive moisture sensor basically a capacitor having a dielectric that is preferably composed of a hygroscopic polymer layer that, depending on the humidity of the ambient air, takes in (absorbs) or releases (desorbs) moisture
Implementation Method 2
The dielectric constant of the polymer material then changes as a function of moisture content
Implementation Method 3
the sensor comprises at least one capacitor comprising at least two electrodes that are arranged, in particular, in a horizontal direction along and on an, in particular, flexible support material
Data Source
AI summary
An apparatus and a method for measuring pressure, gas and/or humidity, the apparatus having at least one sensor with at least one capacitor comprising at least two electrodes that are arranged in a horizontal direction relative to one another along and on a flexible support material. At least one dielectric layer is arranged between the electrodes and at least one at least partially moisture-permeable and/or moisture-absorbing and/or gas-permeable and/or gas-absorbing moisture layer is arranged at least in some places on a side, facing away from a support material, of at least one electrode and/or the dielectric layer. At least one electrode and/or the dielectric layer are thus arranged transversely between the support material and the moisture layer. A capacitance is at least partially changed by moisture hitting the dielectric layer, and a processing unit measures and/or stores this change, so as to create a capacitive moisture sensor.