Workpiece Inspection Device Using Dual Light Projection for Precision
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Solution Overview
Problem
Conventional workpiece inspection devices face increased cycle times when attempting to improve inspection accuracy, as they often require capturing and analyzing entire images, which can be inefficient.
Innovation Solution
A workpiece inspection device and method that uses a first light projection unit to capture initial images, identifies areas requiring detailed inspection, and then employs a second light projection unit to focus on those specific areas for high-accuracy quality determination, while adjusting focus and position to handle different incidence angles and reduce vibration transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If inspection accuracy is improved by capturing and analyzing entire images, then measurement precision is improved, but productivity deteriorates due to increased cycle time
Solution Approach 1:
The inspection process is divided into two stages: first, a rough inspection of the entire workpiece surface using the first light projection unit; second, detailed inspection only of identified defect portions using the second light projection unit. This segmentation allows the system to maintain high measurement precision for defects while reducing overall inspection time by avoiding exhaustive analysis of entire surfaces.
Solution Approach 2:
The system performs partial inspection by capturing images only of portions determined to require detailed inspection, rather than capturing and analyzing entire images. This partial action approach maintains sufficient inspection accuracy for quality determination while significantly reducing the cycle time associated with processing complete image data.
2Device complexity
If a single image capturing unit is used to capture images at different incidence angles, then device complexity is reduced, but measurement precision deteriorates due to focus deviation
Solution Approach 1:
The system dynamically adjusts the focal position of the single image capturing unit between the first and second light projection units based on which unit is actively projecting light. The control unit changes the focal position to match the distance from the workpiece surface to the active light projection unit, thereby maintaining sharp focus and measurement precision despite using a single capturing unit for multiple angles.
Solution Approach 2:
The system changes the focal position parameter of the image capturing unit according to the active light projection unit. When switching between the first and second light projection units, the focal distance is adjusted accordingly, allowing the single image capturing unit to maintain optimal focus for measurements at different incidence angles without requiring multiple capturing units.
3Measurement precision
If the image capturing unit is positioned close to the workpiece for detailed inspection, then measurement precision is improved, but vibration from the moving mechanism adversely affects measurement
Solution Approach 1:
The second light projection unit serves as an intermediary that can be positioned close to the workpiece surface for detailed inspection of defect portions. By using this separate light projection unit rather than moving the image capturing unit closer, the system achieves high measurement precision for detailed inspection while avoiding vibration transmission from the moving mechanism that would affect a closely-positioned capturing unit.
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 enables high-accuracy inspections with reduced cycle times by capturing detailed images only where necessary, maintaining focus and minimizing vibration impact, thus improving overall inspection efficiency.
Implementation Method 1
causing the image capturing unit to be movable by the turning mechanism to a first position where reflection light that is the light projected by the first light projection unit is specularly reflected from the workpiece is received
Implementation Method 2
causing the image capturing unit to be movable by the turning mechanism to a second position where reflection light that is the light projected at the workpiece by the second light projection unit at an incidence angle which is different from the incidence angle of the light projected at the workpiece by the first light projection unit is specularly reflected from the workpiece is received
Implementation Method 3
the linear movement mechanism adjusts a relative distance between the table and the image capturing unit fixing part so that a focus is adjusted to prevent focus deviation caused by a difference due to a difference in the incidence angle
Data Source
AI summary
A workpiece inspection device 1 includes a table (3), image capturing unit fixing part (7), first light projection unit (4), second light projection unit (5), linear movement mechanism (8), turning mechanism (9), quality determination unit (10), and control unit (11). The control unit (11) performs first image capturing step of causing first light projection unit (4) to project light and causing image capturing unit (6) to capture image, detailed inspection portion-determination step of setting, portion of workpiece (2) determined to require detailed inspection based on image captured in the first image capturing step, second image capturing step of causing second light projection unit (5) to project light onto the workpiece (2) and causing image capturing unit (6) to capture image of the detailed inspection-requiring portion, and quality determination step of determining quality of the detailed inspection-requiring portion based on image captured in the second image capturing step.