Optical Inspection System for Glass Surface Defect Detection
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Solution Overview
Problem
Current methods for detecting surface defects on transparent sheets, such as glass, are labor-intensive, inconsistent, and time-consuming, and struggle with detecting defects regardless of their orientation due to sensitivity to the angle of illumination.
Innovation Solution
A method and apparatus that collimates a light beam, uses a beam splitter to illuminate and scatter light on the glass sheet, and employs a lens assembly with an inverse aperture to block reflected light and transmit scattered light to an imaging device for defect detection, ensuring isotropic detection capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If manual inspection methods are used to detect surface defects on glass sheets, then inspection can be performed with simple equipment, but the inspection process becomes labor-intensive, inconsistent, and time-consuming
Solution Approach 1:
The patent replaces manual mechanical inspection with an automated optical inspection system that uses light sources, beam splitters, lenses, and cameras to detect surface defects. This substitution eliminates labor-intensive manual examination while maintaining detection capability, directly resolving the contradiction between equipment simplicity and inspection speed.
Solution Approach 2:
The inspection system is designed to automatically detect, locate, and characterize surface defects without human intervention. The system self-regulates by capturing images, processing defect data, and providing inspection results, thereby achieving high productivity without requiring complex operator involvement.
2Device complexity
If conventional optical inspection methods are used, then the inspection system can be relatively simple, but the detection capability becomes sensitive to defect orientation and inconsistent
Solution Approach 1:
The patent employs multiple light sources positioned at different angles and multiple cameras configured to capture images from various perspectives. This multi-angle illumination and detection approach ensures that defects regardless of their orientation on the glass surface can be consistently detected and characterized, eliminating the orientation sensitivity problem while maintaining reasonable system complexity.
3Area of stationary object
If manual inspection is used to examine large production-sized glass sheets, then the inspection area can be covered, but the inspection time increases significantly
Solution Approach 1:
The inspection system divides the large glass sheet into multiple inspection zones by using multiple light sources and cameras positioned across the inspection area. Each light source-camera pair covers a specific region, allowing parallel inspection of different areas simultaneously. This segmentation enables complete coverage of large sheets while maintaining fast inspection speed, directly addressing the time loss issue.
4Device complexity
If conventional inspection methods are used, then the equipment can be simple, but the ability to detect defects of various orientations is limited
Solution Approach 1:
The inspection system is designed with multiple light sources at different angles and multiple cameras that can detect and characterize all types of surface defects regardless of their orientation, shape, or location on the glass sheet. This universal detection capability is achieved through a coordinated multi-component system that maintains reasonable overall complexity while providing comprehensive defect detection.
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 efficient and consistent detection of surface defects on large glass sheets without sensitivity to defect orientation, significantly reducing inspection time and improving detection accuracy.
Implementation Method 1
A first portion of the light illuminating the first surface of the glass sheet is reflected by the first surface
Implementation Method 2
a second portion of the light illuminating the first surface of the glass sheet is scattered by a defect
Implementation Method 3
The method further comprises receiving the reflected light and the scattered light with a first lens element, the first lens element directing the reflected light and the scattered light to an inverse aperture
Implementation Method 4
wherein the reflected light is blocked by the inverse aperture and the scattered light is transmitted by the inverse aperture
Data Source
AI summary
Methods for detecting defects on the surface of a sheet of material include collimating a beam of light and intersecting the collimated beam of light with a beam splitter. The beam splitter directs a first portion of the intersected beam of collimated light to illuminate a first surface of the sheet, wherein a first portion of the light illuminating the first surface is reflected and a second portion of the illuminating light is scattered by a defect. The reflected and scattered light is received with a first lens element that directs the reflected and scattered light to an inverse aperture. The reflected light is blocked by the inverse aperture and the scattered light is transmitted by the inverse aperture. The scattered light transmitted by the inverse aperture is directed with a second lens element to an imaging device.