Inductive Sensor with Segmented Conductive Patterns
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Solution Overview
Problem
Existing sensors face challenges in providing robust and precise measurements of measurands due to mechanical stress-induced variations in impedance or inductance, which can lead to inaccurate readings and reduced durability, especially in flexible devices with complex geometries.
Innovation Solution
A device comprising a first conductive pattern made of a material insensitive to measurand variations and a second pattern with conductivity that evolves in response to the measurand, arranged in a configuration that allows for precise impedance or inductance measurement, with the second pattern being electrically connected to the first pattern to enhance sensitivity and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensors use dimensional modification or relative positioning changes to detect measurands, then measurement capability is provided, but mechanical stress variations cause impedance or inductance changes leading to measurement inaccuracy
Solution Approach 1:
The sensor is divided into two distinct patterns: a first pattern made of stress-insensitive conductive material and a second pattern made of stress-sensitive material. This segmentation allows the stress-sensitive second pattern to detect dimensional changes while the stress-insensitive first pattern provides a stable reference, thereby resolving the contradiction between providing measurement capability and maintaining measurement accuracy under mechanical stress.
Solution Approach 2:
Different regions of the sensor have different material properties: the first pattern uses stress-insensitive conductive material for stable electrical connection, while the second pattern uses stress-sensitive material for detecting dimensional changes. This local differentiation of material qualities enables the sensor to simultaneously maintain structural stability and detect mechanical variations accurately.
2Adaptability or versatility
If flexible substrates with complex geometries are used to enable dimensional modifications, then sensor adaptability is improved, but mechanical durability decreases due to stress-induced variations
Solution Approach 1:
The sensor employs a composite structure combining two different materials with contrasting properties: a stress-insensitive conductive material for the first pattern and a stress-sensitive material for the second pattern. This composite approach allows the sensor to maintain mechanical durability through the stable first pattern while achieving adaptability through the flexible second pattern that responds to dimensional changes.
3Reliability
If mechanical packaging is provided to protect the sensor elements, then device protection is improved, but space requirements and device complexity increase
Solution Approach 1:
The protective function is merged with the sensing function by integrating both patterns directly onto the flexible substrate without requiring separate mechanical packaging structures. The first pattern's stress-insensitive material inherently protects against false signals while the second pattern provides the sensing capability, eliminating the need for complex additional packaging.
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 enables robust and precise measurement of measurands by isolating the first pattern from environmental influences and focusing on the second pattern's response, improving noise immunity and allowing for real-time, one-off or continuous monitoring of measurands, while also enabling wireless communication and remote power supply through inductive coupling.
Implementation Method 1
a first pattern (11) made of a first conductive material and having a first impedance, a second pattern (12) made of a second material and arranged between a first end (11A) and a second end (11B) of the first pattern (11), the second pattern (12) being in electrical contact with the first pattern (11) so as to form an electrical circuit comprising the first pattern (11) and the second pattern (12), wherein the impedance of the electrical circuit varies in response to a dimensional modification of the second pattern (12) dependent on a variation of a measurand
Implementation Method 2
the impedance of the electrical circuit varies in response to a dimensional modification of the second pattern (12) dependent on a variation of a measurand
Implementation Method 3
enabling wireless communication and remote power supply through inductive coupling
Data Source
Figure 1~2A
Figure 2B~3
Figure 4A~4B
AI summary
Disclosed is a device for determining a measurand, comprising a first pattern (11, 71, 81) made from a first conductive material, the first pattern having a first impedance and having a first end (11A, 61A) and a second end (11B, 61B) spaced apart from the first end, a second pattern (12, 72, 82) at least arranged between the first end and the second end of the first pattern, being in electrical contact with the first pattern. The second pattern has a second impedance that changes continuously as a function of the measurand, such that the impedance or the inductance of the assembly formed by the first and second patterns changes continuously as a function of the measurand. The device also comprises a means (13) for determining the impedance or the inductance of the assembly formed by the first and second patterns.