In-Canal Temperature Sensor Layout for Accurate Ear Core Readings
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Solution Overview
Problem
Existing technologies face challenges in obtaining accurate and continuous core body temperature measurements from within the ear canal due to the narrow and angular geometry of the ear canal, which obstructs a direct field of view for temperature sensors.
Innovation Solution
An ear-wearable electronic device with a trough containing two thermistors on a flexible circuit board is deployed in the ear canal, measuring conductive and convective heat at specific locations to calculate core body temperature using a heat balance equation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a handheld IR sensor is used to measure ear canal temperature, then the device is portable and easy to use, but the measurement accuracy is compromised due to inability to obtain direct field of view to tympanic membrane
Solution Approach 1:
The patent replaces the optical measurement system (handheld IR sensor requiring line of sight) with a thermal conduction-based measurement system. Temperature sensors are placed in direct thermal contact with the ear canal wall, measuring temperature through conductive heat transfer from the tissue rather than through radiation, thereby eliminating the need for direct visual access to the tympanic membrane.
Solution Approach 2:
The patent introduces the ear canal wall tissue as an intermediary medium. Instead of measuring temperature directly at the tympanic membrane through radiation, the sensors measure temperature at the ear canal wall, which acts as a thermal intermediary that conducts heat from deeper structures, providing accurate temperature data without requiring direct line of sight to the target area.
2Measurement precision
If temperature sensors are placed deep in the ear canal to reach the tympanic membrane, then direct temperature measurement is possible, but the device complexity and difficulty of proper positioning increase
Solution Approach 1:
The patent employs self-adjusting mechanisms where the earwearable device automatically positions itself within the ear canal. The flexible in-canal section and trough structure allow the device to conform to the individual ear canal geometry, with temperature sensors automatically achieving proper thermal contact with the ear canal wall without requiring precise manual positioning by the user.
Solution Approach 2:
The patent changes the measurement location parameter from the tympanic membrane (requiring deep insertion) to the ear canal wall (accessible with shallower placement). By measuring temperature at the ear canal wall through controlled thermal contact, the system achieves accurate readings without the complexity of precise deep positioning.
3Measurement precision
If multiple temperature sensors are used to account for conductive and convective heat, then measurement accuracy improves, but the device complexity increases
Solution Approach 1:
The patent combines multiple temperature sensors into a single integrated trough structure. The proximal and distal temperature sensors are housed together in the in-canal section, sharing common support infrastructure and thermal management, which reduces overall device complexity while maintaining the capability to measure both conductive and convective heat components.
Solution Approach 2:
The patent assigns different functional roles to different parts of the sensor arrangement. The proximal temperature sensor specifically measures convective heat, while the distal temperature sensor measures conductive heat, with each sensor optimized for its specific measurement function. This localized functional differentiation improves measurement accuracy without requiring a complex overall system architecture.
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 device provides accurate and continuous core body temperature measurements by stabilizing thermistors with consistent spacing and thermal contact, enabling effective health monitoring and alert generation.
Implementation Method 1
measuring, using a distal temperature sensor disposed in a trough of an enclosure of the device, a first temperature indicative of one or both of conductive heat and convective heat
Implementation Method 2
measuring, using a distal temperature sensor disposed in a trough of an enclosure of the device, a first temperature indicative of one or both of conductive heat and convective heat
Implementation Method 3
measuring, using a proximal temperature sensor disposed in the trough at a location proximal of the distal temperature sensor in an outer ear direction, a second temperature indicative of one or both of conductive heat and convective heat
Implementation Method 4
measuring, using a proximal temperature sensor disposed in the trough at a location proximal of the distal temperature sensor in an outer ear direction, a second temperature indicative of one or both of conductive heat and convective heat
Implementation Method 5
calculating, using a processor of the device, a core body temperature using the pre-established heat balance equation and the first and second temperatures
Data Source
AI summary
Embodiments are directed to an electronic device configured to measure temperature from within an ear canal having a first bend, a second bend, and a tympanic membrane. The device comprises an enclosure comprising an in-canal section dimensioned for deployment in the ear canal. The in-canal section comprises a trough extending axially along at least a portion of the in-canal section and arranged to be positioned between the first bend and the tympanic membrane when the in-canal section is fully deployed in the ear canal. A temperature sensor is disposed in the trough. The temperature sensor comprises a flexible circuit board, a distal temperature sensor disposed on the flexible circuit board, and a proximal temperature sensor disposed on the flexible circuit board and situated proximal of, and spaced apart from, the distal temperature sensor in an outer ear direction.