Inductive Position Encoder Shielded Coil Configuration
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Solution Overview
Problem
Existing inductive position encoder systems face limitations in achieving a combination of high signal strength, compact size, high resolution, cost-effectiveness, robustness to misalignment, and contamination resistance.
Innovation Solution
The electronic position encoder incorporates a scale with a signal modulating pattern and a detector portion featuring a multi-layer circuit element with a field generating coil configuration, shielded conductor layers, and sensing windings, optimized through specific geometric arrangements and configurations to minimize stray signal components and enhance signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional inductive position encoder configurations are used, then contamination resistance is achieved, but signal strength and resolution are limited
Solution Approach 1:
The detector portion is divided into multiple independent receiver coils arranged in series, with each coil contributing to the total signal. This segmentation allows the system to maintain contamination resistance while improving signal strength through cumulative signal addition across multiple coils.
Solution Approach 2:
Multiple receiver coils are connected in series to combine their individual signals into a cumulative total signal. This merging approach enhances signal strength and resolution while maintaining the robustness of the inductive transducer configuration against contamination.
2Volume of moving object
If encoder size is reduced for compact applications, then device portability is improved, but manufacturing precision and alignment robustness deteriorate
Solution Approach 1:
The patent utilizes the z-axis dimension by positioning receiver coils at different depths within the detector portion. This three-dimensional arrangement allows compact overall device size while maintaining precise magnetic field coupling through vertical stacking, thereby preserving alignment robustness in a compact configuration.
3Measurement precision
If multiple receiver coils are added to improve signal strength, then measurement precision is improved, but device complexity increases
Solution Approach 1:
Multiple receiver coils are connected in series, which merges their individual signal paths into a single cumulative signal output. This series connection approach improves signal strength through signal addition while avoiding the complexity of parallel connections and signal processing, as the coils function as a unified sensing element.
4Measurement precision
If shielded conductor layers are added to reduce stray signals, then measurement precision is improved, but manufacturing cost and complexity increase
Solution Approach 1:
Shielded conductor layers are introduced as intermediary elements between the transmitter and receiver coils. These shield layers act as mediators that block stray magnetic fields and reduce parasitic coupling, thereby improving measurement precision. The shielded conductors are integrated into the multi-layer PCB structure, adding minimal complexity while providing effective electromagnetic interference protection.
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
This configuration improves signal strength, accuracy, and robustness while maintaining a compact size and low cost, effectively addressing the limitations of previous systems.
Implementation Method 1
an induced current transducer may be manufactured using printed circuit board technology
Implementation Method 2
Each pattern track comprises signal modulating elements that are arranged to provide a spatially varying characteristic which changes as a periodic function of position along the x-axis direction
Data Source
AI summary
An electronic position encoder includes a scale and detector. The detector includes a field generating coil (FGC) having elongated portions (EPs) bounding a generated field area (GFA) aligned with sensing windings, to provide position signals responsive to the scale interacting with the generated field. Sensing elements and EPs are fabricated in “front” layers of the detector. A transverse conductor portion (TCP) fabricated in a “rear” layer connects the EP of the FGC via feedthroughs. A shield region in a layer between the front and rear layers intercepts at least a majority of a projection of the TCP toward the front layers to eliminate undesirable signal effects. The FGC feedthroughs generate GFC feedthrough stray fields. Feedthrough pairs that connect sensing winding signals to rear layers of the detector are specially configured to mitigate undesirable signal effects that may otherwise result from their coupling to the GFC feedthrough stray fields.