Spring-Loaded Electric Field Sensor for Stable Microwave Plasma Detection
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Solution Overview
Problem
Existing electric field sensors in microwave plasma processing apparatuses face challenges in stably detecting microwave electric fields due to noise interference and external factors like vibration and temperature changes, leading to inconsistent sensitivity and reproducibility.
Innovation Solution
An electric field sensor design featuring a probe with a built-in spring for constant contact with the microwave transmission window and a preload spring to maintain contact with the planar slot antenna, reducing noise and ensuring stable signal detection, even with repeated installation and detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an electric field sensor is inserted into a sensor insertion hole to detect microwave electric fields, then the power output from the antenna or plasma state can be detected, but the detection becomes unstable due to noise interference and external factors like vibration and temperature changes
Solution Approach 1:
A probe is introduced as an intermediary component that physically contacts the microwave transmission window to detect electric fields. This probe serves as a mediator between the microwave field and the detection system, providing stable contact through spring mechanisms that maintain constant pressure despite external disturbances like vibration and temperature changes.
Solution Approach 2:
Spring mechanisms are incorporated to provide dynamic adjustment capability. The first spring maintains constant contact between the probe and the microwave transmission window, while the second spring maintains contact between the probe guide and the planar slot antenna. These dynamic elements allow the system to adapt to thermal expansion, contraction, and vibration, ensuring stable detection.
2Ease of repair
If the sensor is repeatedly installed and detached, then maintenance and replacement become easier, but the sensitivity and reproducibility of detection deteriorate due to loss of contact integrity
Solution Approach 1:
Spring mechanisms provide dynamic contact maintenance that automatically compensates for wear and positioning variations during repeated installation and detachment. The springs ensure that contact pressure is restored after each assembly/disassembly cycle, maintaining detection sensitivity without requiring strict installation confirmation.
Solution Approach 2:
The spring mechanisms are pre-configured to provide cushioning force that compensates for potential contact loss. This beforehand cushioning ensures that even if contact is partially lost during assembly, the spring force restores proper contact, preventing sensitivity degradation from repeated handling.
3Measurement precision
If rigid contact structures are used to ensure stable detection, then measurement precision improves, but the system becomes sensitive to external factors like vibration and temperature changes
Solution Approach 1:
The system changes the mechanical parameter of contact from rigid fixed positioning to flexible spring-loaded contact. This parameter change allows the contact force to adapt dynamically, maintaining stable electrical contact while absorbing mechanical disturbances from vibration and temperature variations through the elastic deformation of the springs.
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 enables stable and sensitive detection of microwave electric fields, maintaining contact integrity despite external factors and improving reproducibility without requiring strict installation confirmation.
Implementation Method 1
a built-in spring and a portion forming a monopole antenna at a tip end thereof so that the tip end of the probe is in constant contact with a rear surface of the microwave transmission window by a pressing force of the built-in spring
Implementation Method 2
a preload spring configured to preload the probe guide downward and press the probe guide so that the tip end of the probe guide comes in constant contact with the planar slot antenna
Implementation Method 3
a probe serving as an inner conductor of a coaxial transmission path and having a built-in spring and a portion forming a monopole antenna at a tip end thereof
Data Source
AI summary
An electric field sensor includes a probe, a cylindrical probe guide, an insulating member, a preload spring and a connector. The probe serves as an inner conductor of a coaxial transmission path and has a portion forming a monopole antenna at a tip end to be in constant contact with a microwave transmission window by a pressing force of a built-in spring thereof. The probe guide is disposed at an outer side of the probe and serves as an outer conductor of the coaxial transmission path. The insulating member is disposed between the probe and the probe guide. The preload spring preloads the probe guide downward and presses the probe guide so that the tip end of the probe guide comes in constant contact with the planar slot antenna. The connector is connected to the probe and the probe guide to connect coaxial signal cables for extracting signals.