Optical Inspection Using Complementary Wavelengths for Surface Unevenness
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Solution Overview
Problem
Conventional optical inspection methods struggle to accurately determine light beam direction and surface unevenness of objects, leading to inadequate inspection of surface states, especially in identifying fine scratches and contamination.
Innovation Solution
An optical inspection method that emits light beams of complementary wavelengths, with a color filter system passing specific wavelengths to isolate specular and scattering light components, allowing for the acquisition and comparison of images to extract surface unevenness information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional optical inspection methods are used to identify light beam direction, then the inspection process is simple, but the measurement precision of light beam direction and surface unevenness is insufficient
Solution Approach 1:
The patent divides the inspection system into multiple imaging units, each equipped with color filters that segment light by wavelength. This segmentation allows different imaging units to capture light beams from different directions with high precision, resolving the contradiction between measurement precision and device complexity by organizing complexity in a structured, modular way
Solution Approach 2:
The patent introduces wavelength as an additional dimension for light beam direction identification. By using color filters to separate light by wavelength and assigning different imaging units to different wavelength ranges, the system achieves precise 3D surface measurement by adding spectral dimension to the spatial measurement process
2Measurement precision
If conventional optical inspection methods are used, then the device structure is simple, but the inspection accuracy of surface states including fine scratches and contamination is inadequate
Solution Approach 1:
The patent segments the spectral range into multiple wavelength bands using color filters, with each imaging unit dedicated to specific wavelength ranges. This segmentation enables precise detection of surface features by analyzing light scattering characteristics at different wavelengths, achieving high inspection accuracy while managing system complexity through modular architecture
Solution Approach 2:
The patent changes the wavelength parameter of illumination light and uses color filters to select specific wavelength ranges for different imaging units. By varying wavelength parameters and analyzing how surface features scatter different wavelengths differently, the system achieves enhanced detection capability for fine scratches and contamination
3Measurement precision
If multiple imaging units with color filters are used to capture light beam direction information, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The patent segments the measurement task across multiple imaging units, each responsible for specific wavelength ranges and light beam directions. This segmentation allows parallel processing of different spectral components, achieving high-precision 3D surface measurement while distributing system complexity across modular, independently manageable units
Solution Approach 2:
The patent designs the multi-imaging-unit system with universal functionality where each imaging unit can process multiple wavelength ranges through color filter switching or multiple filters simultaneously. This multi-functionality reduces the total number of imaging units needed, thereby managing device complexity while maintaining high measurement 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
This method enables precise inspection of surface states by capturing images based on light beam direction, effectively distinguishing between standard and abnormal surface areas, including fine scratches and contamination, with improved accuracy compared to traditional methods.
Implementation Method 1
passing a first wavelength and a second wavelength different from the first wavelength in accordance with light beam directions from a subject
Implementation Method 2
extract unevenness information of the subject by comparing the information of the first image and information of the second image
Data Source
AI summary
According to the embodiment, an optical inspection method includes: emitting, acquiring, and comparing. The emitting includes emitting light beams having a first wavelength and a second wavelength toward an imaging unit in accordance with light beam directions from a subject, with light beam intensities of the first wavelength and the second wavelength being in a complementary relationship. The acquiring includes acquiring each of information of a first image related to the first wavelength and information of a second image related to the second wavelength with the imaging unit. The comparing includes comparing the information of the first image and the information of the second image to extract unevenness information of the subject.