Windowless Vacuum Aperture Using Plasma Ion Exclusion
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Solution Overview
Problem
Existing technologies face challenges in maintaining a vacuum in environments exposed to ambient air without the use of massive vacuum pumps, which are impractical for certain applications, and high-temperature windows are a limiting factor for Electro-Optical/Infrared (EO/IR) sensors on hypersonic platforms.
Innovation Solution
A plasma vacuum pump system using metal mesh screens with an excitation source, such as a laser, to ionize gas and create a plasma, allowing for the maintenance of a vacuum while allowing energy transmission through a 'windowless' design that excludes or admits electromagnetic energy selectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If massive vacuum pumps are used to maintain a vacuum in the presence of a leak, then the vacuum can be maintained, but the system becomes impractical and undesirable due to size and complexity
Solution Approach 1:
The patent replaces the mechanical vacuum pump system with an electrostatic field-based solution. Two screens with opposite electrical charges create an electrostatic field that repels gas molecules, maintaining vacuum without mechanical moving parts. This substitution resolves the contradiction by eliminating the complexity of massive vacuum pumps while maintaining reliable vacuum conditions.
Solution Approach 2:
The patent changes the physical state of the gas by ionizing it into plasma using microwave radiation. The ionized gas particles, being charged, can be controlled and repelled by electrostatic fields. This parameter change from neutral gas to ionized plasma enables vacuum maintenance through electrical fields rather than mechanical means, reducing system complexity.
2Ease of operation
If high temperature windows are installed for EO/IR sensors on hypersonic weapons, then the sensors can operate, but the window technology becomes the limiting factor due to temperature constraints
Solution Approach 1:
The patent removes the window component entirely from the sensor system. By using an electrostatic field barrier instead of a physical window, the sensor can operate without the temperature constraints that limit window materials. This extraction of the window solves the contradiction by eliminating the temperature bottleneck while maintaining sensor functionality.
Solution Approach 2:
The patent introduces an electrostatic field as an intermediary between the hot external environment and the sensor. This field barrier allows thermal energy to be blocked while permitting electromagnetic radiation to pass through, protecting the sensor from high temperatures without requiring thermal management of a physical window.
3Reliability
If a physical window is used to separate vacuum and atmosphere, then vacuum can be maintained, but the window adds emissivity to the optical system reducing signal-to-noise ratio
Solution Approach 1:
The patent replaces the physical window with an electrostatic field barrier. This field-based solution maintains vacuum separation while being transparent to electromagnetic radiation across a broad spectrum. The absence of physical material eliminates emissivity issues, preserving signal-to-noise ratio while maintaining vacuum integrity.
4Reliability
If screens with voltage difference are used to maintain vacuum, then gas can be excluded, but the device complexity increases
Solution Approach 1:
The patent makes the screens serve multiple functions: they act as both vacuum barriers and electromagnetic radiation transmitters. The same screens with voltage applied exclude gas molecules while simultaneously allowing optical energy to pass through. This multi-functionality reduces overall device complexity by eliminating the need for separate vacuum and optical components.
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 the maintenance of a vacuum in open atmospheric environments without solid windows, providing a high signal-to-noise ratio for sensors and allowing for the transmission of energy across a wide range of wavelengths, including UV to LWIR, while preventing gas ingress and offering dynamic pressure control.
Implementation Method 1
an excitation source capable of ionizing gas in the volume, producing a plasma in the volume
Implementation Method 2
The voltage source causes the plasma pump to repel positive particles from a region where a vacuum is to be maintained and to attract negative particles to said region
Data Source
AI summary
A conduit is placed between a vacuum system and the open air or other gaseous environment. A laser or other excitation source is used to ionize the air on the air-side of the conduit. An axial applied electric field is used to repel positive ions from traversing the tube and reaching the region of the vacuum. Electrons are collected in the vacuum region and disposed of using a Faraday cup. The repelled ions assist in creating a counter pressure to sweep neutral atoms out of the tube and back into the ambient air. As a result, a hollow tube can connect an evacuated volume to the open air without compromising the vacuum. This is a “windowless window.” An array of such tubes can be assembled together to increase the area of the aperture.