Layered Vacuum Feedthrough for Stable DBD Plasma Measurement
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Solution Overview
Problem
The measurement and evaluation of DBD plasma discharge face challenges such as complexity, size, and sensitivity, particularly in vacuum setups, making it difficult to achieve reliable pressure and gas composition characterization.
Innovation Solution
A compact vacuum feedthrough with a lens element and dielectric layers, along with a ceramic and metal framework, allows for a continuous radiation path and prevents arc discharges, enabling the generation of a DBD plasma discharge for pressure and gas composition measurement, using a DBD plasma discharge device with a sapphire lens and ceramic components for high sensitivity and wide pressure range operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a DBD plasma discharge setup is used for pressure and gas composition measurement, then measurement capability is provided, but the setup becomes complex and large in size
Solution Approach 1:
The patent combines the optical lens, vacuum feedthrough, and DBD plasma generation components into a single integrated device. The lens is directly coupled with the feedthrough structure, and the electrode assembly is integrated within the same housing, eliminating the need for separate optical systems and plasma generation equipment.
Solution Approach 2:
The device performs multiple functions simultaneously: it generates DBD plasma discharge for gas ionization, focuses the emitted light through the integrated lens, transmits signals through the vacuum barrier, and enables both pressure and gas composition measurements using a single unified system rather than separate specialized devices.
2Measurement precision
If conventional plasma discharge measurement setups are used, then measurement function is achieved, but the device size and complexity increase
Solution Approach 1:
The patent implements a nested structure where the electrode assembly is positioned within the housing, the lens is integrated into the feedthrough structure, and multiple functional components are arranged concentrically or in nested layers, maximizing space utilization and minimizing the overall device volume.
Solution Approach 2:
The optical focusing function and plasma generation function are merged into a single integrated unit, eliminating the need for separate optical benches and plasma chambers that would significantly increase device volume.
3Reliability
If arc discharge occurs instead of DBD plasma discharge, then electrical breakdown happens, but this prevents reliable plasma generation for measurement
Solution Approach 1:
The patent introduces a dielectric barrier layer as an intermediary between the electrodes. This dielectric material prevents direct electrical contact and arc formation while still allowing capacitive coupling to generate stable DBD plasma discharge, thereby mediating between the electrical field and the gas to produce controlled plasma without harmful arcs.
Solution Approach 2:
The patent modifies the electrical parameters by using AC voltage with specific frequency and amplitude ranges, combined with the dielectric barrier, to transform the discharge mode from arc discharge to stable DBD plasma discharge, changing the electrical field characteristics to prevent breakdown while maintaining plasma generation.
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 solution provides a compact, sensitive, and energy-efficient device capable of characterizing pressure and gas composition across a wide pressure range, from vacuum to overpressure, with high-frequency AC voltage, suitable for various applications including the semiconductor industry.
Implementation Method 1
The lens element is transparent to at least one wavelength range in the optical wavelength range and thus constitutes the optical portion of the vacuum feedthrough... radiation arriving from the first side can be focused... concentrate parallel radiation paths arriving from the first side into a focal point
Implementation Method 2
at least one of the electrodes is electrically isolated from the gas space by galvanic separation using a dielectric... the insulation prevents the occurrence of an arc discharge
Implementation Method 3
A DBD plasma discharge (also called a silent electrical discharge or dielectric barrier discharge, abbreviated DBD) is an AC gas discharge... ionization and excitation of molecules and ions to generate plasma light
Data Source
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.