Moiré Pattern Analysis for Grating Alignment Inspection
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Solution Overview
Problem
Current methods for inspecting the alignment of gratings on objects, such as airfoils and solar cells, are laborious and time-consuming, often leading to errors due to their reliance on manual inspection or slow generation of three-dimensional maps.
Innovation Solution
A system and method that analyze a test moiré pattern generated by superposing reference gratings on subject gratings to calculate rotational angles and angular errors, using an analysis unit and notification system to provide real-time feedback on alignment accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual inspection method is used, then operator can visually inspect sections of the object, but the inspection is laborious and may lead to errors
Solution Approach 1:
The patent replaces manual visual inspection with an automated optical measurement system that captures images and processes them through algorithms to determine grating alignment, eliminating human labor and subjectivity while improving both accuracy and efficiency
Solution Approach 2:
The system enables self-inspection by automatically capturing images, processing them through beat line analysis, and generating alignment measurements without requiring operator intervention, making the inspection process autonomous and repeatable
2Measurement precision
If scanning spot system is used to generate three dimensional map, then inspection can be performed, but the generation of the map takes a few hours
Solution Approach 1:
The patent skips the time-consuming three-dimensional map generation step by directly capturing two-dimensional images that contain sufficient information for alignment measurement, dramatically reducing inspection time while maintaining measurement capability
Solution Approach 2:
The system extracts only the essential alignment information needed from the grating structure by analyzing beat lines in captured images, rather than generating complete three-dimensional maps, achieving faster inspection with sufficient precision
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
Enables faster and more accurate inspection of grating alignment, reducing errors and improving efficiency by automating the analysis of grating alignment, particularly beneficial for objects with complex shapes like airfoils.
Implementation Method 1
an imaging device may be configured to generate the test image of the test object
Implementation Method 2
The test image includes a test moiré pattern generated by superposing one or more reference gratings on one or more subject gratings
Data Source
AI summary
A method involves receiving a test image of at least a portion of a test object which includes a test moiré pattern generated by superposing one or more reference gratings on one or more subject gratings. The method further involves analyzing one or more test beat lines in the test moiré pattern and calculating one or more test values based on the analysis of the one or more test beat lines. The one or more test values are a function of one or more rotational angles corresponding to the one or more subject gratings and a shape of at least the portion of the test object. The method also involves calculating one or more angular errors of the one or more subject gratings based on the one or more test values and one or more template values and sending a notification based on the one or more angular errors.