Multimodality Multiplexed Illumination for Optical Inspection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical inspection systems face challenges in providing wide-angle illumination with full angular coverage, leading to inefficiencies and limitations in substrate inspection, particularly in distinguishing patterns and defects on electronic substrates.
Innovation Solution
The implementation of a spatially multiplexed multimodality illumination system that simultaneously illuminates multiple non-contiguous areas of an object with different illumination modalities, using a combination of angular, wavelength-encoded, and polarization-encoded modalities, and temporal modalities, directed by a beam splitter and concentrated through astigmatic concentrators, allowing for near full angular coverage and efficient image acquisition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a single illumination source is used, then the system structure is simple, but the angular coverage is limited and cannot provide wide-angle illumination
Solution Approach 1:
The illumination system is divided into multiple independent light modules, each responsible for illuminating a specific angular sector. This segmentation allows each module to cover a focused angular range while collectively providing wide-angle coverage, resolving the contradiction between comprehensive angular coverage and system complexity.
Solution Approach 2:
The patent introduces spatial multiplexing by arranging light modules at different positions and orientations, adding a spatial dimension to the illumination architecture. This enables simultaneous wide-angle coverage without proportionally increasing system complexity, as the modules work in parallel across different spatial zones.
2Illumination intensity
If multiple light modules are used to achieve wide-angle coverage, then the angular coverage is improved, but gaps appear between illuminated areas
Solution Approach 1:
Adjacent light modules are designed with overlapping illumination fields at their boundaries. This local overlap ensures that no gaps exist between illuminated areas, maintaining continuous and uniform illumination across the entire field of view while preserving the benefits of multiple modular sources.
3Measurement precision
If multiple illumination modalities are applied to different areas, then the inspection accuracy is improved, but the system complexity increases
Solution Approach 1:
Each light module is designed to provide multiple illumination modalities (different wavelengths, polarizations, and temporal characteristics) within a single integrated unit. This multi-functionality allows the system to achieve high inspection accuracy through diverse illumination techniques while avoiding the complexity of separate dedicated sources for each modality.
Solution Approach 2:
The patent combines multiple illumination modalities into unified light modules, merging what would otherwise be separate systems into integrated components. This consolidation reduces overall system complexity while maintaining the ability to apply different modalities to different areas for enhanced inspection accuracy.
4Area of stationary object
If the system uses continuous illumination, then the coverage is complete, but the scanning speed is reduced
Solution Approach 1:
The illumination system uses periodic strobing of light modules synchronized with the scanning motion. Each module illuminates its designated area during specific time intervals corresponding to when the scanned object passes through that field, ensuring complete coverage while maintaining high scanning speeds through efficient time-multiplexed operation.
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 provides wide-angle, uniform, and gap-free illumination, enhancing the accuracy and efficiency of substrate inspection by enabling better pattern distinction and defect identification, while reducing false positives and improving scanning speed.
Implementation Method 1
the system also includes a beam splitter directing illumination from the at least two areas towards the sensor
Implementation Method 2
the system also includes a beam splitter directing illumination from the at least two areas towards the sensor
Implementation Method 3
directed by a beam splitter and concentrated through astigmatic concentrators
Implementation Method 4
concentrated through astigmatic concentrators
Implementation Method 5
an array of light sources outputting light to a corresponding array of light guides
Data Source
AI summary
An inspection system including an illumination subsystem and an image sensing subsystem, the illumination subsystem providing a plurality of illumination modalities, the system simultaneously illuminating at least two areas of an object with different ones of the plurality of illumination modalities, images of which are acquired by a single sensor forming part of the image sensing subsystem.