Arc-Shaped Eddy-Current Brake for Multi-Degree Damping
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Solution Overview
Problem
Conventional damping devices for lithography devices, particularly those using eddy-current brakes, are often limited to damping one or two degrees of freedom, requiring multiple devices for comprehensive damping, which complicates the setup and increases spatial requirements, while rubber-based dampeners face issues with abrasion and contamination.
Innovation Solution
A compact eddy-current brake system utilizing an arc-shaped arrangement of magnets and electrically conductive sheets, allowing for contactless damping of flexibly mounted structural elements across multiple degrees of freedom, including all six, with the magnets arranged in stacks to enhance damping efficiency and reduce parasitic magnetic fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional eddy-current brakes are used for damping, then damping in one or two degrees of freedom is achieved, but multiple devices are required for comprehensive damping, complicating the setup and increasing spatial requirements
Solution Approach 1:
The patent applies universality by designing a single eddy-current brake device that can dampen vibrations across all six degrees of freedom (three translational and three rotational) simultaneously. The device incorporates a reaction mass coupled to the optical element and an actuator system that generates forces in multiple directions, eliminating the need for multiple separate damping devices and reducing overall system complexity while maintaining comprehensive damping effectiveness
Solution Approach 2:
The patent merges the damping function for all six degrees of freedom into a single integrated eddy-current brake device. The reaction mass and actuator system are combined to provide coupled damping across translational and rotational movements, consolidating what would traditionally require multiple independent damping devices into one unified system
2Reliability
If rubber dampeners are used for damping, then damping in multiple degrees of freedom is achieved, but abrasion and contamination problems occur
Solution Approach 1:
The patent replaces the mechanical contact-based rubber dampener system with an eddy-current brake system that uses electromagnetic forces for damping. The actuator system generates forces through electromagnetic interaction with the reaction mass, eliminating mechanical contact and friction between damping components. This substitution removes the sources of abrasion and contamination while maintaining effective damping across multiple degrees of freedom
3Reliability
If multiple damping devices are used to cover all six degrees of freedom, then comprehensive damping is achieved, but spatial requirements increase
Solution Approach 1:
The patent achieves comprehensive damping coverage for all six degrees of freedom within a single compact device footprint. The reaction mass and actuator system are designed to generate forces in multiple directions simultaneously, providing coupled damping that eliminates the need for multiple spatially distributed damping devices and reduces the overall area required for the optical element mounting
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 effective damping across multiple degrees of freedom with a compact arrangement, reducing wear and contamination risks, and maintaining high precision and stability without introducing additional eigenmodes or rigidity issues, thus improving the overall performance and reliability of lithography devices.
Implementation Method 1
a relative movement between the magnets and the electrically conductive sheets in a direction to be damped inducing eddy currents in the electrically conductive sheets
Implementation Method 2
inducing eddy currents in the electrically conductive sheets
Data Source
AI summary
A lithography device includes an eddy-current brake for damping the movement of a structural element of the lithography device. The eddy-current brake includes a plurality of magnets disposed in an arc-shaped arrangement, and a plurality of electrically conductive sheets arranged respectively between adjacent ones of the magnets. A relative movement between the magnets and the electrically conductive sheets in a direction to be damped inducing eddy currents in the electrically conductive sheets.