Linear Actuator Cover Minimizing Gas Adsorption in Vacuum Chambers
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Solution Overview
Problem
There is no linear actuator capable of maintaining a high vacuum level within a vacuum chamber where plasma is generated, as existing actuators fail to effectively control the movement of valve bodies while preventing gas adsorption and plasma interference.
Innovation Solution
A linear actuator with a moving member and cover designed to minimize gas adsorption, featuring a ceramic sintered body for plasma resistance and a metal attachment section with alumite treatment, along with a guide rod and elastic seal members to maintain vacuum integrity and reduce material costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal bellows is used for sealing the slide section, then sealing performance is improved, but plasma resistance deteriorates
Solution Approach 1:
The patent introduces a cover as an intermediary component that separates the metal bellows from the plasma environment. The cover slides on the vacuum chamber wall while the bellows remains protected inside, allowing the bellows to provide sealing without direct plasma exposure. This resolves the contradiction by mediating between the sealing function and plasma resistance requirement.
Solution Approach 2:
The system combines metal bellows (for sealing) with a plasma-resistant cover (likely ceramic or plasma-treated material). This composite structure allows each component to fulfill its specific function: the bellows provides elastic sealing while the cover provides plasma resistance, resolving the material property contradiction.
2Object-affected harmful factors
If the cover covers the entire moving member, then plasma resistance is improved, but gas adsorption increases
Solution Approach 1:
The cover is designed to cover only the specific portion of the moving member that requires plasma protection, rather than the entire surface. By selectively covering only the necessary areas, the patent maintains plasma resistance where needed while minimizing the total surface area exposed to vacuum, thereby reducing gas adsorption.
3Productivity
If a poppet-type valve with metal bellows is used, then low flow rate control is improved, but vacuum maintenance deteriorates
Solution Approach 1:
The cover acts as a mediator that allows the metal bellows to function in maintaining vacuum sealing while protecting it from plasma damage. This enables the poppet-type valve to achieve both low flow rate control capability and reliable vacuum maintenance without the bellows degrading in the plasma environment.
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 actuator effectively seals the vacuum chamber, maintains high vacuum levels, and reduces material costs by minimizing gas adsorption and plasma interference, enabling reliable operation in plasma environments.
Implementation Method 1
featuring a ceramic sintered body for plasma resistance
Implementation Method 2
a metal attachment section with alumite treatment
Data Source
AI summary
A linear actuator is used with a vacuum chamber in which plasma is generated. The linear actuator comprises a moving member extending between the exterior and the interior of the vacuum chamber through an opening provided in the vacuum chamber so as to be rectilinearly reciprocated, a drive section configured to reciprocate the moving member, a cover that covers the moving member, and a slide seal section that provides a seal between the interior and the exterior of the vacuum chamber while allowing the cover to slide thereon. The cover covers a range of the moving member which is moved into both of the interior and the exterior of the vacuum chamber while the moving member is reciprocated by the drive section, and an outer surface of the cover is smaller in the amount of gas adsorption per unit area than an outer surface of the moving member.