Optical Element Deviation Detection Using Dual-Angle Illumination
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Solution Overview
Problem
Existing imprint apparatuses face challenges in achieving high detection accuracy due to installation errors of optical elements, leading to frequent manual adjustments and increased costs, particularly when the installation position of these elements varies over time.
Innovation Solution
A detection apparatus with an optical element arranged at a position optically conjugate to a target surface, featuring a first region for forming illumination light with a specific angle distribution and a second region for forming illumination light with a different angle distribution, along with a measurement mark, and at least one processor to detect the deviation direction and amount of the optical element based on reflection light from the measurement mark.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single illumination region is used to detect alignment marks, then the device structure is simple, but detection accuracy deteriorates when optical elements have installation errors
Solution Approach 1:
The optical element is divided into multiple regions (first region and second region), each responsible for forming illumination light with different angle distributions. This segmentation allows the system to detect deviations in multiple directions simultaneously, improving detection accuracy without requiring complex external adjustment mechanisms.
Solution Approach 2:
The patent introduces a new dimension of detection by using multiple illumination regions with different angle distributions. Instead of relying on a single illumination path, the system adds angular diversity to the illumination, enabling detection of optical element deviations that would be invisible to a single-region system.
2Measurement precision
If manual adjustment is performed frequently to correct optical element installation errors, then detection accuracy can be maintained, but productivity decreases and operational costs increase
Solution Approach 1:
The detection apparatus performs self-diagnosis by automatically detecting installation errors of optical elements using multiple illumination regions. The system identifies deviation directions and amounts without external intervention, enabling automatic correction procedures and eliminating the need for frequent manual adjustments by operators.
Solution Approach 2:
The system establishes a feedback loop where the detector continuously monitors the position and orientation of optical elements by analyzing light reflected from measurement marks. This real-time feedback enables automatic detection and correction of installation errors, maintaining detection accuracy while improving productivity.
3Adaptability or versatility
If the optical element installation position varies over time, then the apparatus becomes more adaptable to different conditions, but detection accuracy deteriorates due to cumulative errors
Solution Approach 1:
The patent changes the parameters of illumination light (angle distributions) based on the detected position and orientation of optical elements. By adjusting illumination angles dynamically, the system compensates for installation variations and maintains accurate detection even when optical element positions vary over time.
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 solution enhances detection accuracy by reducing the impact of optical element installation errors, allowing for automatic correction of deviation and improving alignment precision without the need for frequent manual adjustments, thus reducing operational costs and increasing productivity.
Implementation Method 1
detect a deviation direction and a deviation amount of the optical element based on reflection light from the measurement mark illuminated by the first region and the second region of the optical element
Data Source
AI summary
Provided is a detection apparatus having a high detection accuracy.A detection apparatus comprises an optical element arranged at a position optically conjugate to a target surface, including a first region for forming illumination light that illuminates the target surface with a first angle distribution and a second region for forming illumination light that illuminates the target surface with a second angle distribution, a measurement mark arranged at the target surface; and a detector for detecting a deviation direction and a deviation amount of the optical element based on reflection light from the measurement mark illuminated by the first region and the second region of the optical element.