Optical Inspection Layout for Thick Light-Scattering Objects
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Solution Overview
Problem
Conventional inspection methods struggle to detect foreign substances, defects, and scratches in thick, light-scattering inspection objects due to limited depth of field, large size, and high installation costs, especially in narrow spaces, and fail to distinguish between foreign substances and defects in light-scattering media.
Innovation Solution
A foreign substance/defect inspection device and method utilizing a light source with a light guiding means that ensures one-to-one correspondence between light sources and light receiving elements, reducing crosstalk and enabling high-resolution detection by collimating light beams and using a light receiving optical system with a large depth of field, suitable for both reflective and light-scattering media.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a conventional light receiving system with limited depth of field is used, then the device size can be kept compact, but it cannot detect foreign substances in thick inspection objects
Solution Approach 1:
The light receiving element array is divided into multiple regions, with specific elements assigned to detect light from specific depth ranges. This segmentation allows the system to handle thick inspection objects by processing different depth zones independently, effectively increasing the inspection depth capability without requiring a single complex optical system.
Solution Approach 2:
The patent introduces depth dimensionality into the detection system by assigning different light receiving elements to detect light from different depth ranges. This transforms the traditional two-dimensional surface inspection into a three-dimensional volume inspection capability, enabling detection throughout the thickness of the inspection object.
2Reliability
If X-ray inspection device is used to inspect thick objects, then transmittance is excellent, but radiation control and exposure dose control are required
Solution Approach 1:
The patent uses conventional light sources and light receiving elements instead of expensive and hazardous X-ray equipment. This replacement with safer, shorter-living optical components eliminates radiation exposure risks while maintaining detection capability for thick objects through the use of multiple depth-range specialized elements.
3Measurement precision
If light scattering property of transmitting medium is high, then conventional detection devices cannot detect foreign substances, but this property makes the medium difficult to inspect
Solution Approach 1:
By segmenting the light receiving element array into multiple regions and assigning each region to detect specific depth ranges, the system can isolate and analyze light scattering patterns from different depths. This allows accurate detection of foreign substances even in highly scattering media by focusing on specific depth zones rather than attempting to process all scattered light simultaneously.
4Productivity
If conventional inspection systems are introduced to existing production lines, then inspection coverage can be increased, but installation cost and space requirements increase
Solution Approach 1:
The patent combines multiple detection functions into a single integrated device by using an array of light receiving elements that simultaneously perform surface inspection and deep-layer inspection. This merging of functions eliminates the need for separate inspection devices, reducing installation cost and space requirements while maintaining comprehensive inspection coverage.
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 accurate detection of foreign substances and defects in thick, light-scattering objects with high resolution and reduced crosstalk, allowing for inspection in narrow spaces and overcoming the limitations of conventional systems.
Implementation Method 1
a light guiding means (32) guiding light beams (33) emitted from a plurality of light sources (31)
Implementation Method 2
light receiving optical system with a large depth of field
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
One pixel unit including at least one light receiving element of a light receiving element array (photodiode array) and a light source have a one-to-one correspondence, and only when the light source emits light, the light beam is detected by at least one light receiving element (one pixel unit) corresponding to the light source. An illumination optical system includes a light guiding means for guiding to an inspection object by reducing an interval between optical axes of light beams emitted from a plurality of light sources in an arrangement direction of a plurality of the light sources.