Thermal Vacuum Gauge Interlaced Microstructures
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Solution Overview
Problem
Existing vacuum sensors, such as Pirani gauges, require significant data processing to accurately determine vacuum levels and often involve cumbersome calibration to account for error sources, limiting their efficiency and accuracy.
Innovation Solution
A thermal vacuum gauge with interlaced heating and sensing microstructures on a substrate, where heat transfer is primarily through conduction rather than convection, allowing for more accurate and efficient measurement of vacuum levels by isolating heating and sensing elements and utilizing thermal conductivity changes with varying gas pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Pirani type vacuum detectors (heated wire) are used to measure vacuum levels, then pressure measurement capability is achieved, but significant data processing is required to infer ambient pressure and considerable calibration work is needed to account for error sources
Solution Approach 1:
The device segments the measurement function into two independent parts: a heating element (heater) and a sensing element (temperature sensor), positioned close to each other. This segmentation allows the temperature sensor to directly measure the temperature of the heating element, providing a direct measurement signal that requires minimal data processing compared to inferring pressure from overall detector performance.
Solution Approach 2:
The heating element serves as an intermediary between the vacuum environment and the temperature sensor. By measuring the temperature of this intermediary element (which is directly affected by thermal conduction from the surrounding gas), the device obtains a direct indicator of gas pressure without requiring complex inference algorithms.
2Measurement precision
If Pirani type vacuum detectors are used to measure vacuum levels, then pressure measurement capability is achieved, but considerable calibration work is needed to account for error sources and deviations
Solution Approach 1:
The heating element serves its dual purpose: it heats the surrounding gas for thermal conduction measurement and simultaneously acts as the temperature sensing target. This self-service approach eliminates the need for separate calibration of heating and sensing functions, as the system uses itself as the measurement reference.
Solution Approach 2:
The invention merges the heating function and the temperature sensing function into a single integrated structure where the heater is the sensed object. This merging eliminates the need for complex calibration to account for discrepancies between heating performance and temperature measurement, as they are inherently linked in the same physical structure.
3Measurement precision
If heated wire detectors are used for vacuum measurement, then pressure sensing is achieved, but the device structure becomes large and requires extensive calibration work
Solution Approach 1:
The invention transitions from a one-dimensional heated wire structure to a two-dimensional configuration where a heating element and temperature sensor are positioned in close proximity (about two microns apart). This dimensional change allows for much smaller device footprint while maintaining measurement capability through enhanced thermal coupling between the heating and sensing elements.
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 reduces the need for extensive data processing and provides more accurate pressure indications across a wide range of pressures, from high to low, by leveraging the change in thermal conductivity of gases, thus enhancing the sensitivity and reliability of vacuum measurements.
Implementation Method 1
heat transfer is not dominated by convection but rather by conduction
Implementation Method 2
the change in thermal conductivity of gases, thus enhancing the sensitivity and reliability of vacuum measurements
Data Source
AI summary
A system for determining a gas pressure or gauging a vacuum in a hermetically sealed enclosure. One or more heater structures and one or more temperature sensor structures situated on a substrate may be used in conjunction for measuring a thermal conductivity of a gas in the enclosure. Each heater has significant thermal isolation from each sensor structure. Electronics connected to each heater and sensor of their respective structures may provide processing to calculate the pressure or vacuum in the enclosure. The enclosure may contain various electronic components such as bolometers.