Stripe Pattern Illumination for Transparent Lens Defect Detection
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Solution Overview
Problem
Manual inspection of transparent test specimens, such as ophthalmic lenses, is subjective, time-consuming, and lacks reproducibility, making it difficult to achieve uniform results and hindering the expansion of production capacities.
Innovation Solution
A testing device with a linearly movable illumination device that generates a stripe pattern using multiple light sources, allowing the image acquisition device to capture the light as uniform stripes, reducing the influence of individual factors and improving defect detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual inspection is used to detect defects in transparent test specimens, then the inspection can be performed with simple equipment, but the inspection result is subjective and lacks reproducibility
Solution Approach 1:
The patent replaces the manual mechanical inspection system with an automated optical inspection system. A light source illuminates the test specimen, and a camera captures images of the specimen. The captured images are then processed by evaluation software to automatically detect defects. This substitution eliminates human subjectivity and variability, providing consistent and reproducible inspection results while maintaining high defect detection accuracy.
2Productivity
If manual inspection is used, then training requirements are reduced, but the inspection process is very time-consuming and productivity is low
Solution Approach 1:
The patent replaces manual inspection with an automated system consisting of a light source, camera, and evaluation software. This automation eliminates the need for extensive employee training while dramatically increasing inspection speed and productivity. The system can process multiple test specimens continuously without fatigue or monotony affecting performance, thereby reducing both training time and inspection time per unit.
3Measurement precision
If automated inspection with stripe patterns is used, then defect detection accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent segments the illumination system into multiple independent light sources arranged in linear arrays. These light sources can be individually controlled to generate stripe patterns across the test specimen. The segmentation allows for precise control of illumination geometry without requiring a single complex illumination device, thereby improving defect detection accuracy while managing system complexity through modular design.
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
The solution enhances the reproducibility and accuracy of defect detection in transparent test specimens by ensuring consistent light distribution and reducing the need for extensive employee training, thereby facilitating faster production capacity expansion.
Implementation Method 1
an illumination device for transilluminating test specimens to be examined... Typical defects that appear on and/or in the test specimens can be divided into three different classes according to their visual effect. These are light-absorbing defects, light-refracting defects and light-diffracting defects.
Data Source
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AI summary
The invention relates to a testing device (1) for detecting defects of transparent test specimens (5), in particular of ophthalmological lenses, with an illumination device (2) for transilluminating test specimens (5) to be examined and with an image acquisition device (3) for imaging the test specimen (5) transilluminated by the illumination device (2). The illumination device (2) comprises a plurality of linearly adjustable light sources (8) for generating a stripe pattern (7). In order to capture the stripe pattern (7), the acquisition duration of the image acquisition device (3) can be adjusted in such a way that the light emitted by each of the light sources (8) is detected as a light stripe (19.1). Furthermore, the invention relates to a testing method for detecting a defect of a transparent specimen.