Thermal Resistance Measurement via Sinusoidal Phase Detection
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Solution Overview
Problem
Current methods for measuring thermal resistance between a thermal component of an instrument and a consumable, such as a thermoelectric cooler (TEC) and a flow cell, are inefficient, often requiring stepwise power inputs that can be mechanically, thermally, and electrically stressful, and may not detect interface issues like contamination or improper loading without additional sensors.
Innovation Solution
A method using a periodic sinusoidal drive input to a thermal component, allowing for phase-sensitive detection without changing power input, which reduces stress and allows for high sensitivity measurements of thermal resistance without requiring a thermal sensor on the consumable, by calculating resistance values based on phase shifts and calibrated equations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If stepwise power inputs are used to measure thermal resistance, then measurement can be performed, but mechanical, thermal, and electrical stress increases on the thermal component
Solution Approach 1:
The patent applies periodic sinusoidal drive input to the thermal component instead of stepwise power inputs. This periodic excitation allows measurement of thermal resistance through phase-sensitive detection while avoiding the mechanical, thermal, and electrical stress associated with abrupt step changes in power input.
Solution Approach 2:
The patent replaces the mechanical stepwise power input method with an electrical periodic signal approach. By using sinusoidal electrical drive and phase-sensitive detection, the measurement is achieved through electrical signal processing rather than mechanical power changes, reducing stress on the thermal component.
2Measurement precision
If additional thermal sensors are placed on the consumable to detect interface issues, then detection sensitivity improves, but device complexity increases
Solution Approach 1:
The patent enables the thermal component to serve itself by using its existing thermal sensor to detect interface issues. The method analyzes the phase response of the thermal component's own temperature fluctuations to contamination or improper loading, eliminating the need for separate sensors on the consumable and reducing system complexity.
Solution Approach 2:
The patent makes the existing thermal sensor multi-functional by using it both for its primary temperature monitoring role and for detecting interface issues through phase analysis. This universal use of the existing sensor eliminates the need for additional dedicated sensors, reducing device complexity while maintaining detection sensitivity.
3Measurement precision
If traditional measurement methods are used, then thermal resistance can be measured, but data acquisition time increases and sensitivity is reduced
Solution Approach 1:
The patent employs phase-sensitive detection that continuously monitors the phase response of the thermal component to periodic excitation. This feedback mechanism enables rapid determination of thermal resistance by analyzing phase shifts in real-time, significantly reducing data acquisition time while improving measurement sensitivity compared to traditional methods.
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 method reduces mechanical, thermal, and electrical stress on the thermal component, enables rapid data acquisition, achieves high sensitivity, and detects thermal interface issues like contamination or improper loading, improving the quality and integrity of thermal control in biochemical reactions.
Implementation Method 1
driving the thermal component using a periodic sine wave input
Implementation Method 2
measuring a plurality of temperature outputs from a thermal sensor responsive to driving the thermal component
Data Source
AI summary
A method for measuring thermal resistance between a thermal component of an instrument and a consumable includes contacting a known consumable with a thermal component to be tested; driving the thermal component using a periodic sine wave input based on a predetermined interrogation frequency; measuring temperature outputs from a thermal sensor responsive to the periodic sine wave input; multiplying the temperature outputs by a reference signal in phase with the periodic sine wave input and calculating the resultant DC signal component to determine an in-phase component X; multiplying the plurality of temperature outputs by a 90° phase-shifted reference signal and calculating the resultant DC signal component to determine a quadrature, out-of-phase component Y; calculating a phase offset responsive to the periodic sine wave input based on tan−1 (Y/X) or atan2(X,Y); and determining a resistance value for the thermal interface using a calibrated resistance-phase offset equation and the calculated phase offset.