Segmented Decoupling Joint for EUV Mirror Thermal Expansion
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Solution Overview
Problem
Existing decoupling joints in EUV mirrors fail to adequately absorb thermally induced expansions without introducing constraint forces or mechanical tensions, leading to optical aberrations and limited installation space challenges.
Innovation Solution
A decoupling joint composed of multiple separate joint segments, with at least two segments shifted relative to one another in the loading direction, adapted to the optical element's contour and mechanical loading, optimizing stress distribution and reducing installation space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a decoupling joint is used to absorb thermal expansion of EUV mirrors, then thermal deformation is reduced, but constraint forces and mechanical tensions are introduced leading to optical aberrations
Solution Approach 1:
The decoupling joint is divided into multiple joint segments (first joint segment, second joint segment, etc.) that can independently deform. This segmentation allows each segment to accommodate thermal expansion in different directions, absorbing thermal deformation without generating constraint forces or mechanical tensions that would cause optical aberrations.
Solution Approach 2:
The joint segments are designed with different degrees of freedom, where at least one segment can rotate about an axis perpendicular to the optical axis, and another segment can rotate about the optical axis. This dynamic configuration allows the joint to adapt to thermal expansion dynamically without creating mechanical tensions.
2Strength
If the decoupling joint is optimized for stress resistance, then mechanical tensions are reduced, but the installation space required increases
Solution Approach 1:
The joint segments utilize rotational degrees of freedom in different dimensions (perpendicular to optical axis, and around optical axis) to achieve stress resistance. This multi-dimensional movement capability allows the joint to accommodate thermal expansion without requiring excessive installation space, as the segments rotate within the available space rather than requiring linear expansion room.
Solution Approach 2:
The joint segments are arranged in a nested configuration where segments can rotate and deform within the space occupied by other segments. This nested arrangement maximizes the use of available installation space while maintaining stress resistance through multiple degrees of freedom.
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 allows for free thermal expansion of EUV mirrors without constraint forces, reducing mechanical stresses and optical aberrations while minimizing space requirements.
Implementation Method 1
the EUV mirrors are, among other things, heated as a result of absorption of the radiation emitted by the EUV light source and, associated therewith, undergo thermal expansion or deformation
Data Source
AI summary
An assembly comprises an element that is mechanically stressed during operation or transport in at least one loading direction, and a decoupling joint for mechanically mounting the element. The decoupling joint effects at least partial decoupling in the loading direction. The decoupling joint is composed of a plurality of separate joint segments. At least two of these joint segments are shifted relative to one another in the loading direction in a stepped arrangement.