Fiber Tip Temperature Sensing for Small Fluid Volumes
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Solution Overview
Problem
Existing temperature measurement apparatuses for small fluid volumes, such as those used in PCR tests, face challenges due to the large size of metallic resistance sensors and the complexity of fiber-optic solutions, which are not suitable for precise temperature monitoring in small volumes and require costly spectral analysis.
Innovation Solution
An apparatus using an optical fiber with a fiber tip and additional reflectors to introduce reference reflections, employing a coherent detector to determine temperature based on phase shifts of optical signals, allowing for increased accuracy and range of measurements without additional complexity or cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If metallic resistance sensors are used to measure fluid temperature, then temperature measurement is achieved, but the sensor size becomes too large (probe diameter at least 1mm) for small fluid volumes
Solution Approach 1:
The patent replaces metallic resistance sensors (mechanical/electrical system) with an optical fiber-based temperature sensing system. The optical fiber tip acts as the temperature sensor, utilizing optical interference patterns rather than electrical resistance changes. This substitution enables temperature measurement in small fluid volumes without the size constraint of traditional metallic sensors, as the optical fiber can be made with a much smaller diameter while maintaining measurement capability.
2Reliability
If fiber bragg gratings are used for temperature monitoring, then fiber-optic temperature sensing is achieved, but the device length becomes longer than 10mm and complex spectral analysis is required
Solution Approach 1:
The patent extracts the temperature sensing function from the complex fiber bragg grating system by using a simple optical fiber tip with an additional reflector. Instead of relying on spectral analysis of bragg gratings, the invention uses optical interference between reflections from the fiber tip and the additional reflector. This extraction simplifies the measurement system while maintaining fiber-optic immunity to electromagnetic interference, eliminating the need for complex spectral analysis equipment.
3Measurement precision
If fiber modal interferometers are used for temperature measurement, then temperature sensing is achieved, but the interrogation system becomes complex
Solution Approach 1:
The patent creates a simplified copy of the interferometric sensing principle by using a basic optical fiber tip with an additional reflector instead of complex fiber modal interferometers. The interference pattern is generated by the optical path difference between light reflected from the fiber tip and light reflected from the additional reflector. This copying approach maintains the essential interferometric temperature sensing mechanism while dramatically simplifying the interrogation system, making it more suitable for practical applications in small fluid volumes.
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
Enables precise temperature determination of small fluid volumes with high sensitivity and speed, using coherent optical time domain reflectometry to enhance measurement accuracy and range, suitable for parallel measurements in multiple fluid samples.
Implementation Method 1
a first additional reflector introduced into the at least one fiber tip at a first predetermined distance from an outer end of the at least one fiber tip... receiving a first light signal that corresponds to parts of the optical signal that are reflected at the outer end of the at least one fiber tip and a second light signal that corresponds to parts of the optical signal that are reflected at the first additional reflector
Implementation Method 2
determining a difference of the optical phases of the first light signal and the second light signal, and determining the temperature of the at least one fluid based on the difference of the optical phases
Implementation Method 3
an optical fiber... a first end of the optical fiber is connected to the at least one fiber tip, and a second end of the optical fiber is connected to the processing apparatus
Data Source
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AI summary
The present invention relates to an apparatus for determining the temperature of at least one fluid, wherein the apparatus (1) comprises an optical fiber (2), wherein a first end of the optical fiber (3) is connected to at least one fiber tip (4), and a first additional reflector (5) introduced into the at least one fiber tip (4) at a first predetermined distance from an outer end of the at least one fiber tip (6), and wherein a second end of the optical fiber (7) is connected to a processing apparatus (8), wherein the processing apparatus (8) comprises an optical source (9), wherein the optical source (9) is configured to launch an optical signal into the optical fiber, and a coherent detector (10), wherein the coherent detector (10) is configured to determine the temperature of at least one fluid by receiving a first light signal that corresponds to parts of the optical signal that are reflected at the outer end of the at least one fiber tip (6) when the at least one fiber tip (4) is inserted into the at least one fluid and a second light signal that corresponds to parts of the optical signal that are reflected at the first additional reflector (5) when the at least one fiber tip (4) is inserted into the at least one fluid, determining a difference of the optical phases of the first light signal and the second light signal, and determining the temperature of the at least one fluid based on the difference of the optical phases of the first light signal and the second light signal.