Surface Shape Machining Optimization for Precision Optical Elements
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Solution Overview
Problem
Conventional methods for adapting the surface shape of optical elements in projection exposure systems are time-consuming and inefficient, often requiring sequential optimization steps that lead to prolonged processing times and potential quality losses.
Innovation Solution
A device and method that utilize a shape manipulation unit with multiple processing tools and a control unit to optimize surface changes through an optimization process, minimizing the total time required for surface modification by considering all machining operations holistically, allowing for efficient material removal, compaction, or deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional sequential optimization steps are used for surface shape adaptation, then manufacturing precision is improved, but processing time increases significantly
Solution Approach 1:
The patent applies preliminary action by performing a rough machining operation first to remove large deviations from the target surface shape, followed by a finishing operation to achieve precise surface adaptation. This staged approach allows the system to address major shape errors before fine-tuning, significantly reducing the total time required compared to attempting precise machining from the start.
Solution Approach 2:
The surface modification process is segmented into multiple processing operations with different levels of precision. The patent divides the machining task into coarse machining (removing large deviations) and fine machining (achieving target precision), allowing each operation to be optimized independently for its specific purpose rather than using a single high-precision operation for the entire process.
2Manufacturing precision
If multiple processing operations are used to adapt surface shape, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent employs a universal shape manipulation device that can perform multiple processing operations with varying degrees of fineness. The same device is capable of both rough machining and fine machining tasks, eliminating the need for separate specialized tools for each operation type and thereby reducing overall system complexity while maintaining high manufacturing precision.
3Ease of manufacture
If sequential optimization approach is used for machining operations, then ease of implementation is improved, but productivity decreases
Solution Approach 1:
The patent implements preliminary rough machining to remove the bulk of surface deviations before performing fine machining operations. This approach dramatically reduces the material that needs to be removed in subsequent precision operations, thereby increasing overall productivity without sacrificing the simplicity of sequential process implementation.
Solution Approach 2:
The processing sequence is segmented into distinct roughing and finishing phases, each optimized for its specific function. This segmentation allows the system to efficiently handle large deviations in the first phase and focus computational and machining resources on achieving target precision in the second phase, thereby maximizing productivity while maintaining ease of implementation.
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 enables high-precision surface adaptation in a shorter time frame by optimizing the distribution of machining operations across multiple tools, preventing overfitting and unnecessary time expenditure, and avoiding the need for intermediate thresholds, thus improving time efficiency and quality.
Implementation Method 1
a particle beam, such as an electron beam, with a diameter in the range of the smallest structures to be produced, can be directed onto selected sub-areas of the surface to achieve local densification and thus local depression of the surface
Implementation Method 2
achieve local densification and thus local depression of the surface according to the desired surface structuring
Implementation Method 3
particle beams can also be used for direct material removal from the surface of the irradiated optical element and thus generally for modifying the surface shape of the object
Data Source
Figure 1
Figure 2~3
AI summary
A device (10) for changing the shape of a surface (12) of an object (14) comprises a shape manipulation device (16) configured to effect a change in the surface of the object in at least two machining operations depending on a control variable (56), wherein at least one section of the surface is machined in each of the machining operations. Furthermore, the device comprises a control device (50) configured to determine a target (56v) for the control variable (56) of the shape manipulation device from a predetermined target change (52) of the surface shape of the object by means of an optimization (60) in which the total time required to generate the surface change resulting from the at least two machining operations is minimized.