Miniaturized Ionization Pressure Sensor with Cold Field Emission
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Solution Overview
Problem
Existing pressure sensor devices are unable to accurately measure very low pressures below 10^-12 mbar due to X-ray generation, have complex and bulky designs, and require external calibration and diagnostics, making them unsuitable for miniaturized, self-contained, and precise applications in extreme environments.
Innovation Solution
A miniaturized, integrated device with an ionization-based detection member, electronic processing means, and interface means, featuring a cold field-effect emission source, ion extraction means, and a reference pressure sensor, which reduces X-ray interference, enables self-calibration and diagnostics, and measures pressures down to 10^-13 mbar with improved sensitivity and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If hot cathode ionization gauges are used to measure low pressure, then measurement capability is achieved, but X-ray generation increases noise and reduces measurement precision below 10^-12 mbar
Solution Approach 1:
The patent changes the operating parameters of the ionization gauge by using field emission instead of thermal emission, operating at room temperature instead of high temperature (1800-2000K), which eliminates Joule heating effects and reduces X-ray generation while maintaining measurement capability
Solution Approach 2:
The patent replaces the thermal field emission mechanism with a cold field emission mechanism using sharp tips or nanotubes, substituting thermal energy with electrical field energy to emit electrons without heating, thereby eliminating the source of X-ray generation
2Reliability
If macroscopic electronic components are mounted to enable operation, then device functionality is achieved, but device dimensions and complexity increase
Solution Approach 1:
The patent merges the ionization gauge sensor, electronic processing circuitry, memory, and interface components into a single integrated microdevice, eliminating the need for separate macroscopic components and reducing overall device complexity while maintaining full functionality
Solution Approach 2:
The integrated device performs multiple functions including pressure sensing, signal processing, data storage, calibration, and wireless communication within a single unit, eliminating the need for separate dedicated components for each function
3Measurement precision
If calibration and diagnostics are performed outside the instrument, then measurement accuracy can be adjusted, but device self-sufficiency and reliability in extreme environments decrease
Solution Approach 1:
The patent implements self-calibration and self-diagnostics capabilities within the device, allowing it to automatically adjust and verify its own measurement accuracy without external intervention, making it self-sufficient for operation in extreme or remote environments
Solution Approach 2:
The device incorporates feedback mechanisms where measurement data is continuously monitored and used to automatically adjust calibration parameters, ensuring maintained measurement precision through internal feedback loops without requiring external calibration equipment
4Use of energy by moving object
If field-effect electron sources (nanotubes, micro-tips) replace standard filaments, then electron emission is improved, but electronic current density and X-ray generation increase proportionally without improving sensitivity
Solution Approach 1:
The patent changes the emission mechanism from thermal to cold field emission, and further optimizes by using specific geometries (sharp tips, nanotubes) with controlled electrical fields, achieving high electron emission current density without the proportional increase in X-ray generation that occurs with conventional heating 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
The device achieves high accuracy and reliability in measuring low pressures, is compact and self-sufficient, and can perform both total and partial pressure measurements, overcoming the limitations of existing technologies by reducing X-ray interference and enabling self-calibration and diagnostics.
Implementation Method 1
electrons emitted by an ionization source, arranged in such a way to be passed through by ionization particles (e.g., electrons) generated by the source, such that the ionization particles ionize the gas particles
Implementation Method 2
cold field-effect emission source, configured to emit electrons
Implementation Method 3
ion extraction means, configured to determine a preferential trajectory for the generated ions
Data Source
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AI summary
A miniaturized device for measurements of very low level pressure 1 is described. The device 1 comprises an ionization-based detection member 11, configured to detect a pressure value Pi, electronic processing means 10, operatively connected to the ionization-based detection member 11, and configured to generate a measured pressure value P based on the detected pressure value Pi, and further comprising interface means 15, operatively connected to the electronic processing means 10 and configured to provide in output the measured pressure value P. The ionization-based detection member 11, the electronic processor 10 and the interface means 15 are comprised in a single integrated device. The ionization-based detection member 1 1 comprises an ionization source 21 and an ionization region 20, containing gas particles the pressure of which has to be measured, arranged so as to be passed through by ionization particles (e.g., electrons) generated by the source 21, so that the ionization electrons ionize the gas particles, thus generating respective ions. The ionization-based detection member 11 further comprises ion extraction means 22, configured to determine a preferential trajectory for the generated ions, passing through at least one ion extracting window 31, through which the ions leave the ionization region 20; and at least one ion detector 23, configured to detect ions and generate an electrical variable depending on the amount of ions detected and representative of the pressure value of the gas particles that are present in the ionization region 20. The at least one ion detector 23 having micrometer dimensions and is arranged at a respective ion extraction window 31, so as to be shielded against trajectories of X rays generated by impacts of the ionizing electrons with parts of the ionization region 20 other than the at least one ion detector (23).