PCB Coil Position Transducer With Through-Coil Magnetic Element
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Solution Overview
Problem
Conventional transducers are bulky, costly, and unreliable, with non-linear frequency-movement characteristics, and existing designs do not achieve optimal performance and reliability.
Innovation Solution
A transducer design featuring a circuit board with integrated coil and interaction element, where the interaction element passes through a hole in the coil, allowing for a more compact, reliable structure with adjustable self-inductance and improved linear frequency-movement characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional wound coil is used, then the coil can be manufactured with traditional winding processes, but the device becomes bulky, costly, and prone to reliability issues due to winding and soldering processes
Solution Approach 1:
The patent replaces the traditional mechanical winding and soldering processes with a planar coil structure formed by conducting tracks on a printed circuit board. This substitution eliminates the complex mechanical assembly steps, reduces the number of components, and improves reliability by removing potential failure points associated with winding and soldering operations.
Solution Approach 2:
The patent transitions from a three-dimensional wound coil structure to a two-dimensional planar coil structure on a printed circuit board. This dimensional change reduces the axial height and overall complexity of the device while maintaining the electromagnetic functionality through the planar spiral track design.
2Ease of manufacture
If a conventional wound coil is used, then the coil can provide sufficient inductance, but the device becomes costly and difficult to manufacture with consistent quality
Solution Approach 1:
The patent replaces manual or automated winding and soldering operations with standardized printed circuit board fabrication processes. The planar coil is created through photolithography and etching of conducting tracks, which are highly repeatable and controllable manufacturing processes that ensure consistent quality across production batches.
Solution Approach 2:
The patent enables precise control of inductance parameters by adjusting the geometry of the planar spiral tracks (number of turns, track width, spacing, outer and inner diameters) during the PCB design stage. These geometric parameters can be precisely controlled in the manufacturing process, allowing for accurate and repeatable inductance values without requiring complex assembly adjustments.
3Measurement precision
If the interaction element is positioned outside the coil, then the structure is simpler, but the frequency-movement characteristic becomes non-linear and the signal range is reduced
Solution Approach 1:
The patent positions the interaction element inside the planar spiral coil structure, with the element extending axially through the center of the coil. This nested configuration allows the interaction element to pass through multiple turns of the coil, creating a more linear magnetic coupling relationship that improves the linearity of the frequency-movement characteristic while maintaining a compact integrated structure.
4Reliability
If a traditional coil with exposed wire is used, then the coil can be adjusted for inductance, but the sensor becomes susceptible to parasitic capacitance and drift in humid conditions
Solution Approach 1:
The patent uses a printed circuit board as a substrate that provides a non-hygroscopic, electrically insulating support for the coil tracks. The conducting tracks are typically covered with protective solder mask and conformal coating layers that prevent moisture ingress and eliminate parasitic capacitance issues associated with exposed wires in humid environments, thereby improving long-term stability.
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 new design achieves a more compact, cost-effective, and reliable transducer with enhanced linear frequency-movement characteristics and increased signal range, reducing parasitic capacitance and drift issues.
Implementation Method 1
an interaction element adapted to interact magnetically with the coil as a result of a movement of the membrane, in such a way that the self-inductance of said coil may be varied depending on the relative position of the interaction element with respect to the coil
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
An electrodynamic position transducer (1) comprises: a rigid, hollow casing (2, 4) in which a membrane (5) is clamped which, together with a portion of the casing (2, 4), defines at least one chamber (6, 7) of variable volume; a coil (14) comprising at least one conductive track (14.1-14.6) formed on a support (16); an interaction element (13; 13') adapted to interact magnetically with the coil (14) as a result of a movement of the membrane (5), in such a way that the inductance of the coil (14) may be varied depending on the relative position of the movable element with respect to the coil (14); and a circuit (17) coupled to the coil (14) and adapted to provide electrical signals of which a parameter may be varied depending on the inductance of the coil (14). A hole or recess (18) is formed in the support (16) of the coil (14), which hole or recess is configured to receive the interaction element in such a way that one end (13a; 13.1a, 13.2a) of the interaction element (13; 13') may be positioned flush with or beyond a turn (T) of the coil (14).