Gas Bearing Table Device to Suppress Pitching and Positioning Error
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Solution Overview
Problem
Conveyance devices with table devices experience decreased positioning accuracy due to table pitching and inclination, which affects the precise placement of objects.
Innovation Solution
A table device with a dual-axis gas bearing system, including first and second bearing members and guide members, that supports the table to maintain its position and orientation, preventing pitching and inclination by generating vertical and horizontal forces through gas bearings and suction force generation devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single gas bearing is used to support the table, then the device complexity is reduced, but the positioning accuracy deteriorates due to table pitching and inclination
Solution Approach 1:
The single gas bearing is divided into multiple segmented gas bearings (first gas bearing and second gas bearing) arranged along the moving direction. Each gas bearing independently supports a portion of the table's weight, preventing table pitching and inclination that would occur with a single bearing, thereby maintaining positioning accuracy without excessive complexity
Solution Approach 2:
Multiple gas bearings are positioned at specific locations along the table's moving direction, with each bearing providing localized support. The bearing members are arranged to correspond with different sections of the table, ensuring that each section is properly supported to prevent local deformation and maintain overall positioning accuracy
2Length of moving object
If the distance between bearing members is reduced, then the device size is minimized, but the positioning accuracy deteriorates as the table can pitch and incline within the moving range
Solution Approach 1:
The problem of table pitching in one dimension (moving direction) is solved by adding bearing members in the same dimension but distributed along it. The bearing members are arranged along the moving direction (first axis) rather than concentrating them in a single point, effectively using dimensional distribution to prevent rotation while maintaining compact overall device size
3Manufacturing precision
If multiple gas bearings are added to prevent table pitching, then the positioning accuracy is improved, but the device complexity increases
Solution Approach 1:
The multiple gas bearing members serve dual functions: they collectively support the table's weight (load-bearing function) and simultaneously prevent table pitching and inclination (stabilization function). This multi-functionality reduces the need for separate stabilization mechanisms, thereby limiting the increase in device complexity while achieving positioning accuracy
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 effectively suppresses decreases in positioning accuracy, ensuring precise object placement and reducing the likelihood of defective products in semiconductor and flat panel display manufacturing.
Implementation Method 1
a first bearing member that is provided to the second base, includes a first gas supply port facing the first reference surface, and forms a gas bearing between the first bearing member and the first reference surface with a gas supplied through the first gas supply port
Data Source
AI summary
A table device including: a first base including a first reference surface; a second base including a second reference surface, and movable on the first reference surface in a direction parallel to a first axis; a first bearing member provided to the second base, and forming a gas bearing between the first bearing member and the first reference surface; a second bearing member provided to the second base, apart from the first bearing member relative to a direction parallel to a second axis perpendicular to the first axis, and forming a gas bearing between the second bearing member and the first reference surface; and a table movable on the second reference surface. A distance between the first bearing member and the second bearing member is longer than a dimension of a moving range of the table relative to the direction parallel to the second axis.