Vacuum Feedthrough Structure for Compact DBD Plasma Sensing
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Solution Overview
Problem
Measuring and evaluating DBD plasma discharge is challenging due to issues with service life, vacuum suitability, size, and complexity of structures, as well as sensitivity, particularly in achieving compact sensors for pressure and gas composition analysis.
Innovation Solution
A vacuum feedthrough comprising a lens element, glass rings, dielectric and ceramic hollow cylinders, and a metal frame, which forms a compact, electrical-optical feedthrough allowing continuous radiation paths for plasma discharge measurement, and an electrode arrangement with overlapping conductive layers to generate a DBD plasma discharge, suitable for wide pressure ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a compact sensor design is implemented for DBD plasma discharge measurement, then the size and complexity of the setup is reduced, but the lifetime and vacuum suitability of the components deteriorate
Solution Approach 1:
The feedthrough is divided into distinct functional segments: a first section with the lens element for optical transmission, a second section with dielectric hollow cylinders for electrical insulation, and a third section with metal hollow cylinders for structural support and vacuum sealing. This segmentation allows each component to be optimized for its specific function while maintaining overall compactness and reliability.
Solution Approach 2:
The feedthrough employs composite construction combining different materials: glass or sapphire for the lens element (optical transparency), dielectric materials like glass or ceramic for insulation layers, and metal materials for structural components. This composite approach enables the compact sensor to achieve both small size and high reliability by selecting materials optimized for each functional requirement.
2Volume of moving object
If a compact sensor design is implemented for DBD plasma discharge measurement, then the size and complexity of the setup is reduced, but the sensitivity deteriorates
Solution Approach 1:
The lens element is positioned at the front of the feedthrough to preliminarily focus and transmit the plasma discharge light before it passes through the multiple insulating and structural layers. This preliminary optical action ensures that the light signal is optimized for detection despite the compact multi-layered structure, maintaining sensitivity while reducing overall sensor size.
3Reliability
If multiple hollow cylinders and rings are used in the feedthrough structure, then the electrical insulation and vacuum sealing are improved, but the device complexity increases
Solution Approach 1:
The hollow cylinders and rings are designed to perform multiple functions simultaneously: the dielectric hollow cylinders provide both electrical insulation and vacuum sealing, while the metal hollow cylinders provide structural support, electrical grounding, and additional vacuum sealing. This multi-functionality reduces the number of separate components needed, simplifying the overall structure while maintaining high reliability.
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 compact, sensitive, and durable sensors for pressure and gas composition analysis across a wide pressure range, with improved plasma discharge stability and extended component lifespan, suitable for both vacuum and atmospheric conditions.
Implementation Method 1
The lens element is transparent for at least one wavelength range in the optical wavelength range and thus represents the optical part of the vacuum feedthrough. There is at least one continuous radiation path for radiation from an optical wavelength range starting from a first point on a first side, through the lens element to a second point on a second side of the vacuum feedthrough.
Implementation Method 2
A DBD plasma discharge (also called silent electrical discharge or dielectric barrier discharge, abbreviated DBD) is an AC gas discharge in which at least one of the electrodes is electrically insulated from the gas space by galvanic separation using a dielectric.
Implementation Method 3
The adjacent elements (elements are the lens element and the other elements from the above list) are connected to one another in a vacuum-tight manner to form a sealing surface which separates a first side, in particular a vacuum side, and a second side, in particular an atmosphere side, of the vacuum feedthrough from one another.
Data Source
Figure 1
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AI summary
A vacuum feedthrough (10) which is constructed in radial layers comprises the following elements (from inwards to outwards): - a lens element (11), - a first ring (12) made of glass, - a first hollow cylinder (13) made of a first dielectric material, - a first electrically conductive layer (18), - a second hollow cylinder (14) made of glass, - a third hollow cylinder (15) made of ceramic, - a second ring made of glass (16), and - a frame (17) made of metal. On the basis of the vacuum feedthrough, the invention additionally relates to an electrode assembly, to a device for generating a DBD plasma discharge, to a measuring device for characterizing a pressure and/or a gas composition, and to a method for operating the measuring device.