Optical Pressure Sensor Temperature Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Optical pressure sensors face challenges in accurately measuring absolute pressure due to temperature sensitivity, non-linear response over larger pressure ranges, and calibration difficulties, especially at high temperatures, which affects their ability to measure both dynamic and static pressures effectively.
Innovation Solution
The integration of temperature sensing optical cavities adjacent to pressure sensing optical cavities in the sensor head, using Fabry-Perot cavities, allows for improved temperature compensation by optically measuring temperature near the pressure cavity, enabling more accurate pressure measurements. This involves a dual-wavelength interrogation system with separate optical analyzers for pressure and temperature sensing, where the pressure sensing cavity is interrogated at a higher frequency to capture dynamic changes and the temperature sensing cavity at a lower frequency to match temperature fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If temperature sensing is performed using a separate temperature sensor spaced apart from the pressure cavity, then the device complexity is reduced, but the temperature measurement accuracy deteriorates due to temperature gradients in high-temperature environments
Solution Approach 1:
The patent merges temperature sensing and pressure sensing functions into a single integrated sensor head. The temperature sensing optical cavity and pressure sensing optical cavity are both formed within the same sapphire sensor head, allowing simultaneous measurement of temperature and pressure at the same location, thereby eliminating temperature gradient errors while maintaining device compactness.
Solution Approach 2:
The sapphire sensor head serves multiple functions: it acts as both the structural housing and contains both temperature sensing and pressure sensing optical cavities. This multi-functional design allows a single component to perform multiple measurement tasks, reducing the need for separate sensors and their associated mounting hardware.
2Device complexity
If the optical pressure sensor uses a single optical cavity for pressure measurement, then the device complexity is low, but the ability to compensate for temperature effects deteriorates
Solution Approach 1:
The sensor head is segmented into functionally distinct optical cavities: a temperature sensing optical cavity and a pressure sensing optical cavity. Each cavity is optimized for its specific measurement function, with the temperature cavity providing reference data for compensation algorithms that correct pressure measurements, thereby improving overall measurement reliability.
Solution Approach 2:
The temperature sensing optical cavity acts as an intermediary element that provides temperature data used to compensate for thermal effects on the pressure measurement. By measuring temperature independently within the same sensor head, the system can correct for thermal expansion and refractive index changes in the pressure cavity, improving pressure measurement accuracy.
3Manufacturing precision
If the sensor is designed for high linearity over large pressure ranges, then the manufacturing precision is improved, but the sensitivity to small dynamic pressure variations deteriorates
Solution Approach 1:
The system employs dynamic measurement strategies where the interrogation frequency and analysis methods are adapted based on the measurement requirements. For small dynamic pressure variations, high-frequency interrogation captures rapid changes with high sensitivity, while for large static pressure ranges, lower-frequency measurements with temperature compensation maintain linearity and accuracy.
Solution Approach 2:
The system changes measurement parameters such as interrogation frequency, optical wavelength, and analysis methods based on the measurement conditions. By adjusting these parameters, the sensor can optimize between linearity for large ranges and sensitivity for small variations, rather than being constrained to a fixed operating mode.
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 provides more accurate and linear pressure measurements across a wide range, reducing errors and improving the sensor's ability to distinguish between static and dynamic pressures, enhancing its sensitivity and range while maintaining accuracy at high temperatures.
Implementation Method 1
Optical pressure sensors implemented using one or more optical cavities, such as Fabry Perot cavities... pressure is measured by pressure-induced deflection of at least one reflective surface of a physical cavity in the sensor head
Implementation Method 2
The dimensions and optical characteristics of a pressure sensor head for use at elevated temperatures will typically be sensitive to the temperature of operation, for example due to changes in material properties and due to thermal expansion
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
An optical pressure sensor is disclosed having a pressure sensing optical cavity. A temperature sensing optical cavity at the sensor head is used by an interrogator to correct a pressure signal for effects of temperature. The optical cavities may be, for example, Fabry Perot cavities in the sensor head.