Low Noise Oximetry Cable Conductive Cords
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Solution Overview
Problem
Existing oximetry cables suffer from noise interference due to triboelectric charge buildup, which corrupts low-level signals, and previous solutions like graphite coatings or coextruded conductive PVC sheaths introduce rigidity and manufacturing difficulties.
Innovation Solution
Incorporating conductive polymer cords, such as hollow conductive PVC tubes, twisted with detector cables to drain triboelectric charge and reduce noise, while maintaining flexibility and ease of manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If graphite coatings or coextruded conductive PVC sheaths are used to reduce triboelectric noise, then noise interference is reduced, but cable rigidity increases and manufacturing becomes difficult
Solution Approach 1:
The cable structure is segmented into distinct functional layers: inner conductor, insulator, optional inner shield, and outer conductive shield. This segmentation allows each layer to be optimized independently, making manufacturing easier while maintaining noise reduction effectiveness.
Solution Approach 2:
An optional inner shield layer acts as an intermediary between the inner conductor and the outer conductive shield. This intermediary layer helps manage triboelectric charge buildup and provides additional EMI protection without requiring the outer shield to be directly adjacent to the conductor, simplifying the overall manufacturing process.
2Object-affected harmful factors
If graphite coatings or coextruded conductive PVC sheaths are used to reduce triboelectric noise, then noise interference is reduced, but cable flexibility decreases
Solution Approach 1:
The outer conductive shield is implemented as a thin, flexible braided or foil structure rather than a rigid coating. This allows the shield to maintain its noise reduction function while conforming to cable bending and movement, preserving cable flexibility for ease of operation.
Solution Approach 2:
The cable uses composite material construction with multiple layers having different properties: the outer conductive shield provides EMI protection while the underlying insulator and jacket materials provide flexibility. This composite structure achieves both noise reduction and flexibility that single-material solutions cannot provide.
3Object-affected harmful factors
If coextruded conductive PVC sheath is used to reduce noise, then triboelectric charge is drained, but cable rigidity increases
Solution Approach 1:
The outer conductive shield uses thin, flexible braided or foil structures instead of thick coextruded conductive PVC. This thin-film approach provides sufficient triboelectric charge drainage and EMI protection while maintaining cable flexibility and avoiding excessive rigidity.
Solution Approach 2:
The cable design changes the conductivity parameter distribution through multiple layers rather than using a single thick conductive layer. The outer shield provides the necessary charge drainage function with minimal thickness, while flexibility is maintained through the overall layered construction and material selection.
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 conductive cords effectively reduce triboelectric noise, improve signal quality, and provide a more flexible and cost-effective solution compared to previous methods, ensuring accurate physiological parameter measurement in oximetry systems.
Implementation Method 1
One internal noise source is due to a triboelectric effect, which includes static charges that build when two materials rub together.
Implementation Method 2
The cords are twisted with the detector cables and adapted to drain triboelectric charge away from detector wires
Data Source
AI summary
In an embodiment, one or more conductive cable cords are twisted with the sensitive signal carrying cables. The cords may advantageously comprise dummy wires, or very flexible hollow cables without an inner conductor. As the conductive cords do not carry and inner conductor, the conductive cords are individually flexible and small, resulting in a twisted bundle that more is flexible while potentially having a smaller outer diameter.