Vacuum Stage Scale Support for Thermal Error Isolation
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Solution Overview
Problem
Existing stage devices in vacuum environments suffer from posture errors due to thermal deformation and curvature of scale plates, leading to reduced positioning accuracy and increased vibration, especially at higher speeds.
Innovation Solution
A stage device with a scale tray structure that includes a free support unit between the scale plate and lower axis table, using elastic support members to prevent deformation transmission and maintain linearity, combined with a magnetic levitation guide for high-speed positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the stage movement speed is increased to improve throughput, then productivity is improved, but motor heating and friction heat increase causing thermal deformation of the table which leads to posture error
Solution Approach 1:
A scale tray is introduced as an intermediary component between the lower axis table and the scale plate. The scale tray acts as a mediator that decouples the scale plate from direct attachment to the thermally deforming table, allowing the scale plate to maintain its linearity while the table can undergo thermal deformation during high-speed operation.
2Manufacturing precision
If the scale plate is rigidly fixed to the lower axis table, then manufacturing precision is maintained, but thermal deformation of the table causes posture error
Solution Approach 1:
The scale tray serves as a protective intermediary that isolates the scale plate from the thermal deformation effects of the lower axis table. This intermediary structure allows the table to be rigid for positioning while the scale plate remains thermally isolated to maintain measurement accuracy.
3Object-affected harmful factors
If the scale plate is supported through a spring to reduce thermal deformation transmission, then thermal deformation effect is reduced, but support stiffness deteriorates causing vibration
Solution Approach 1:
The scale tray provides a rigid intermediary support structure that differs fundamentally from spring-based solutions. It maintains high support stiffness to prevent vibration while simultaneously blocking thermal deformation transmission through its geometric design that decouples thermal paths from the scale plate.
Solution Approach 2:
The support structure is segmented into distinct functional zones: the lower axis table for movement, the scale tray for thermal isolation and support, and the scale plate for measurement. This segmentation allows each component to optimize its properties without compromising the others.
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 reduces posture errors and enhances positioning accuracy, allowing high-speed operations without compromising precision, suitable for charged particle beam and vacuum devices.
Implementation Method 1
a free support unit between the scale plate and the lower axis table, wherein the free support unit includes an elastic support member supporting the scale plate from below
Implementation Method 2
positioning accuracy by contactless support and 6-axes control is improved by applying magnetic levitation guide
Data Source
AI summary
A stage device includes: a sample installation unit in which a positioning target is installed; a scale plate used to measure displacement of the sample installation unit in a vertical direction; and a lower axis table configured to support the scale plate. A free support unit is provided between the scale plate and the lower axis table.