Optical Component Positioning via Stray Magnetic Field Compensation
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Solution Overview
Problem
Existing methods for positioning optical component parts in optical systems, such as projection exposure apparatuses, fail to accurately compensate for the effects of stray magnetic fields, leading to optical aberrations and reduced precision.
Innovation Solution
A method that utilizes a sensor device to detect stray magnetic fields and generates correction signals for actuating members of displacement devices, employing force or position feedforward control models to compensate for these fields, allowing for precise positioning of optical component parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a sensor device is added to detect stray magnetic fields, then positioning precision is improved, but device complexity increases
Solution Approach 1:
A sensor device is introduced as an intermediary component to detect stray magnetic fields in the region of the optical component part. The sensor device includes one or more sensor elements that measure the magnetic field, providing data to the control device which then calculates compensation signals. This intermediary measurement system enables precise detection and compensation of magnetic field effects without requiring fundamental changes to the optical system itself.
2Manufacturing precision
If feedforward control models are used to compensate magnetic field effects, then positioning precision is improved, but computational requirements and control complexity increase
Solution Approach 1:
The control device performs preliminary calculations using feedforward control models (force feedforward control model or position feedforward control model) to determine compensation signals before the magnetic field effects fully manifest. Based on sensor data about the stray magnetic field, the system pre-calculates the necessary compensation forces or position adjustments and applies them proactively, preventing optical aberrations before they occur rather than reacting to them afterward.
3Measurement precision
If multiple sensor elements are used to detect stray magnetic fields, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The sensor device is segmented into multiple independent sensor elements, each capable of detecting the stray magnetic field at its specific location. This segmentation allows the system to map the spatial distribution of magnetic field effects across different regions of the optical component part. Each sensor element provides localized measurement data that contributes to the overall compensation strategy, enabling precise, location-specific corrections.
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
This approach enables substantial compensation of stray magnetic field effects, improving the precision of optical component part positioning by up to 90%, reducing residual optical aberrations and maintaining optical quality, especially in high-frequency excitations.
Implementation Method 1
provision is made of a sensor device for detecting a stray magnetic field in the region of a component part (34) of the optical system
Implementation Method 2
The stray magnetic field can be produced, in particular, by an electromagnetic device, in particular a controllable electromagnetic device for displacing one of the component parts of the optical system
Data Source
AI summary
For the purposes of positioning a component part, provision is made in an optical system for a stray magnetic field to be detected via a sensor device and for a correction signal for compensating the effect of the stray magnetic field on the positioning of the component part to be ascertained.