Contact Force Sensor with Tuned Amplifiers for Medical Probes

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Solution Overview

Problem

Current medical probes, such as cardiac ablation catheters, face challenges in accurately sensing contact force between the probe and tissue due to interference from noise signals, which reduces the signal-to-noise ratio (SNR) and affects the sensitivity of contact force calculations.

Innovation Solution

The implementation of a contact force sensor with a spring or elastic element, coupled with a transmitter and receiving antennas, uses narrow-band amplifiers with resonant circuits to amplify specific frequency signals, enhancing the signal-to-noise ratio and improving the accuracy of contact force calculations by filtering out noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If narrow-band amplifiers with resonant circuits are used to amplify specific frequency signals, then the signal-to-noise ratio is enhanced and measurement precision is improved, but the device complexity increases due to additional circuit components

Engineering Contradiction:
Improvecontact force measurement precisionVSAvoidsensor circuit complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by tuning the resonant frequency of the amplifiers to match the operating frequency of the contact force sensor. This frequency matching optimizes the signal amplification while filtering out noise, thereby improving measurement precision without requiring complex broadband amplification circuits.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The resonant circuits act as intermediary elements between the sensor signal and the amplification process. These circuits selectively amplify only the desired frequency range, serving as a frequency-based mediator that improves signal-to-noise ratio while maintaining circuit simplicity through targeted frequency selection.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If narrow-band amplifiers are used to filter noise signals, then the signal-to-noise ratio improves, but the device complexity increases due to additional filtering components

Engineering Contradiction:
Improvesignal-to-noise ratioVSAvoidamplifier circuit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent utilizes resonant vibration principles in the electrical domain, where the amplifiers are designed to resonate at specific frequencies matching the sensor output. This resonant amplification naturally filters out non-resonant noise signals, improving reliability while avoiding the need for separate complex filtering stages.

Inventive Principle:
Principle #18Mechanical vibration

Solution Approach 2:

The narrow-band amplifiers perform multiple functions simultaneously: they amplify the desired signal frequency while inherently filtering out noise. This multi-functionality eliminates the need for separate amplification and filtering circuits, thereby improving signal-to-noise ratio without proportionally increasing device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 approach significantly improves the sensitivity and accuracy of contact force sensing, enhancing procedures like radio-frequency ablation and electro-potential mapping by providing a clearer and more precise measurement of the force applied between the catheter and tissue.

Implementation Method 1

each of the narrow-band amplifiers includes a respective resonant circuit, which is coupled to the FET and has a resonant frequency that matches the given range of frequencies

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 2

a contact sensor including a spring or elastic element, having first and second ends

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3613372B1Contact force sensor comprising tuned amplifiers
Publication Date: 2023.03.08 BIOSENSE WEBSTER (ISRAEL) LTD
  • EP3613372B1 patent drawingFigure 1
  • EP3613372B1 patent drawingFigure 2

AI summary

A probe includes an elastic element having first and second ends, a transmitter, one or more receiving antennas and one or more narrow-band amplifiers. The transmitter is coupled to the first end and is configured to transmit signals in a given range of frequencies. The one or more receiving antennas are coupled to the second end and are configured to receive the signals. The one or more narrow-band amplifiers have a pass-band that matches the given range of frequencies and are configured to amplify the signals received by the one or more receiving antennas, respectively.