Stent Inspection Device Using Dark-Field Illumination
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Solution Overview
Problem
Current methods for inspecting cardiovascular stents, particularly small precision-cut tubes, face challenges such as human error, slow inspection processes, and difficulties in automatic inspection due to simultaneous illumination of inner and outer surfaces, leading to defects like rough edges and surface contamination that can be life-threatening.
Innovation Solution
A device utilizing a combination of dark-field and transmittent illumination, along with a rotating mechanism and optical imaging system, allows for selective illumination and inspection of both inner and outer surfaces, enhancing contrast and enabling precise automatic detection of defects using image-processing algorithms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If both inner and outer surfaces of the stent are illuminated simultaneously, then complete surface coverage is achieved, but reflections occur that prevent automatic inspection
Solution Approach 1:
The illumination system is segmented into separate light sources for the inner surface and outer surface of the stent. The first light source illuminates only the inner surface while the second light source illuminates only the outer surface, preventing simultaneous illumination and resulting reflections that would compromise automatic inspection quality.
2Measurement precision
If manual inspection under stereo microscope is used, then detailed visual examination is possible, but the process is slow and expensive
Solution Approach 1:
The manual mechanical inspection process under stereo microscope is replaced with an automated optical inspection system using cameras and image processing algorithms. This substitution maintains high inspection accuracy for detecting defects while dramatically increasing inspection speed and eliminating the cost of manual labor.
Solution Approach 2:
The inspection system performs self-examination through automated image capture and processing. The camera system captures images of the stent surfaces and algorithms automatically detect defects, eliminating the need for human operators to manually examine each stent while maintaining consistent inspection quality.
3Manufacturing precision
If profile projector is used for multi-dimensional inspection, then dimensional data can be obtained, but numerical dimensional data is not supplied for process control
Solution Approach 1:
The optical inspection system is integrated with a control system that provides numerical dimensional data feedback for process control. The camera captures images of the stent dimensions and the system automatically processes this data to provide quantitative measurements that can be used for real-time process monitoring and control, eliminating the information loss present in traditional profile projectors.
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 quick and precise automatic inspection of stent surfaces, reducing human error and improving detection of defects, thereby ensuring safer stent functionality and production efficiency.
Implementation Method 1
A device utilizing a combination of dark-field and transmittent illumination
Implementation Method 2
A device utilizing a combination of dark-field and transmittent illumination
Data Source
AI summary
A device for automatic illumination and inspection of tubular probes, in particular stents, is proposed, with rotatable means for holding the probes that are to be inspected, with an electronic camera and associated lens, with a computer-based electronic imaging system, and with means for illuminating the probe that is to be inspected. The probe surfaces are illuminated by means of a combination of dark field illumination and transillumination.