Capacitance Sensor Probe for Accurate Patient Temperature

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing temperature measurement methods for patients face inaccuracies due to variations in probe cover thickness, which are difficult and costly to manufacture within narrow tolerance ranges, leading to errors in core temperature determination.

Innovation Solution

A temperature probe equipped with a capacitance sensor and a temperature sensor that measures body cavity temperature, using a method to determine core temperature by calculating the difference in capacitance and compensating for probe cover thickness variations, thereby reducing errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If probe cover thickness is controlled within a narrow tolerance range to reduce measurement error, then measurement precision improves, but manufacturing cost and difficulty increase significantly

Engineering Contradiction:

Improvecore temperature determination accuracyVSAvoidprobe cover manufacturing difficulty

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent replaces the mechanical approach of controlling probe cover thickness through manufacturing tolerances with an electrical measurement approach using a capacitance sensor. The capacitance sensor measures the actual thickness of the probe cover in use, and the system compensates for thickness variations through software algorithms, eliminating the need for expensive narrow-tolerance manufacturing while maintaining measurement accuracy.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the parameter being controlled from fixed manufacturing tolerance to dynamic measurement and compensation. Instead of relying on the probe cover thickness being within a narrow range during manufacturing, the system measures the actual capacitance value that reflects the thickness and adjusts the temperature calculation accordingly, allowing broader manufacturing tolerances while maintaining precision.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If algorithms are used to compensate for probe cover thickness variations, then ease of manufacture improves, but measurement precision deteriorates due to additional error introduction

Engineering Contradiction:

Improveprobe cover manufacturing flexibilityVSAvoidcore temperature determination accuracy

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent implements a feedback mechanism where the capacitance sensor continuously measures the actual probe cover thickness during use, and this measured value is fed back into the temperature calculation algorithm. This real-time feedback allows the system to compensate for the specific thickness of the probe cover being used, eliminating the need for predetermined estimates and reducing error accumulation.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system performs self-characterization by measuring its own probe cover thickness through the capacitance sensor and using this information to correct its own measurements. This self-service approach eliminates reliance on external calibration data or predetermined compensation values, improving accuracy while maintaining manufacturing flexibility.

Inventive Principle:

Principle #25Self-service

3Ease of operation

If predetermined estimates are used to compensate for thickness variations, then ease of operation improves, but measurement precision worsens due to error accumulation

Engineering Contradiction:

Improvetemperature measurement simplicityVSAvoidcore temperature determination accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The system automatically measures the probe cover capacitance and performs compensation without requiring user input or selection. The capacitance sensor self-characterizes the probe cover thickness, and the processor automatically applies the appropriate compensation, maintaining ease of operation while eliminating error accumulation from predetermined estimates.

Inventive Principle:

Principle #25Self-service

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 provides more accurate core temperature measurements by directly measuring the thickness of the probe cover and compensating for its effect, enhancing the precision of patient temperature assessments.

Implementation Method 1

The shaft includes a distal end, a proximal end, and a tip at the distal end. The temperature probe also includes a capacitance sensor disposed on one of the handle and the shaft, the capacitance sensor configured to measure a change in capacitance when positioned proximate a conductor.

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

The temperature probe further includes a temperature sensor disposed on the shaft, the temperature sensor configured to measure a body cavity temperature of a patient.

Methodology Applied

Scientific EffectThermal energy detection:

Data Source

PatentUS9138149B2Systems and methods for determining patient temperature

Publication Date: 2015.09.22 WELCH ALLYN INC

AI summary

A temperature probe includes a handle and a shaft extending from the handle. The shaft includes a distal end, a proximal end, and a tip at the distal end. The temperature probe also includes a capacitance sensor disposed on one of the handle and the shaft, the capacitance sensor configured to measure a change in capacitance when positioned proximate a conductor. The temperature probe further includes a temperature sensor disposed on the shaft, the temperature sensor configured to measure a body cavity temperature of a patient.