Surface Inspection Using Non-Parallel Light Sheets
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Solution Overview
Problem
Existing surface inspection methods for planar objects require complex configurations, including image capturing devices and shield bodies, to detect defects, which increases costs and processing time.
Innovation Solution
A method using two non-parallel inspection lights that are parallel to the object's surface in a side view, allowing for defect detection and position specification by measuring changes in light intensity, eliminating the need for multiple cameras and complex image processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple high-resolution cameras are used to inspect the entire width of the product, then inspection coverage is improved, but device complexity and alignment difficulty increase
Solution Approach 1:
The patent extracts the essential function of defect detection from the complex camera system and implements it using a single light source and detector. By using a light sheet that illuminates the entire width of the product simultaneously, the system achieves full inspection coverage without requiring multiple cameras, thereby eliminating alignment complexity while maintaining comprehensive inspection area coverage.
Solution Approach 2:
The patent replaces the mechanical camera system with an optical field-based system. Instead of using multiple cameras to capture images and process them computationally, the invention uses a light sheet to illuminate defects directly and detects them through optical changes, substituting mechanical imaging with optical detection to simplify the system while maintaining inspection coverage.
2Measurement precision
If image processing with multiple cameras is used, then defect detection capability is improved, but processing time increases
Solution Approach 1:
The patent replaces complex image processing operations with direct optical detection. Instead of capturing images with multiple cameras and processing them through computational algorithms, the system uses a light sheet to directly illuminate defects and detects them through optical signal changes, eliminating the time-consuming image processing step while maintaining high defect detection capability.
Solution Approach 2:
The patent skips the intermediate step of image capture and processing by directly detecting defect-induced optical changes. The light sheet illuminates the product and the detection system immediately captures optical signal variations caused by defects, rushing through the inspection process without the time-consuming steps of image acquisition and computational analysis required by camera-based systems.
3Measurement precision
If a shield body and light projection device are used, then defect detection accuracy is improved, but device complexity increases
Solution Approach 1:
The patent extracts the core function of the shield body and light projection device from the complex apparatus structure. Instead of using a physical shield body to guide light and a separate projection device, the invention uses a light sheet that naturally defines the illumination area and eliminates the need for complex light guiding structures, thereby reducing apparatus complexity while maintaining defect detection accuracy.
Solution Approach 2:
The patent makes the light sheet serve multiple functions simultaneously: it illuminates the product surface, defines the inspection area, and eliminates the need for separate shield bodies and projection devices. This multi-functional approach reduces the number of components required while maintaining the accuracy benefits of controlled light illumination.
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 simplifies the inspection process, reduces data processing time, and enables faster inspection speeds while maintaining high accuracy, without the need for multiple cameras or complex image processing.
Implementation Method 1
detecting a presence or absence of a defect derived from a surface irregularity part or an internal gap of a planar inspection object to be conveyed in a predetermined direction, using a change in intensity of inspection light
Data Source
AI summary
The present invention provides a method of inspecting a surface including detecting a presence or absence of a defect derived from a surface irregularity part of a planar inspection object to be conveyed in a predetermined direction, using a change in intensity of inspection light, the inspection light including at least two inspection lights that are parallel to a surface of the inspection object in a side view of the inspection object and pass over the surface of the inspection object or through the inspection object in a direction intersecting the conveyance direction in a plan view of the inspection object, the two inspection lights being non-parallel to each other in the plan view.