Imaging Unit Distance Control for Multi-Wavelength Component Inspection
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Solution Overview
Problem
Existing component mounting machines face issues with chromatic aberration of magnification affecting focal distances due to different wavelengths, leading to inaccurate imaging of components.
Innovation Solution
Adjust the distance between the camera and the holding member based on the image forming point considering longitudinal chromatic aberration, using specific light sources and resolving power values to suppress aberration effects, and process images with accurate focal distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple light sources emitting different wavelengths are used for imaging, then imaging capability is improved, but chromatic aberration of magnification causes focal distances to differ, deteriorating imaging precision
Solution Approach 1:
The patent changes the parameter of distance between the camera and holding member based on the wavelength of light used. By adjusting this distance according to the specific wavelength (e.g., blue light vs red light), the system compensates for chromatic aberration of magnification, allowing multiple wavelengths to be used without sacrificing imaging precision
Solution Approach 2:
The patent performs preliminary measurement to obtain the image forming point for each wavelength before actual imaging. The control device stores the relationship between wavelengths and proper distances in advance, then uses this pre-acquired information to automatically adjust the camera-holding member distance, eliminating the need for real-time trial and error
2Device complexity
If focal distances are kept the same for different wavelengths, then device simplicity is maintained, but chromatic aberration causes distances from optical axis to differ, deteriorating imaging accuracy
Solution Approach 1:
The patent makes the distance between camera and holding member dynamic rather than fixed. The distance is adjusted according to the wavelength of light being used, transforming a static system into a dynamic one that adapts to different imaging conditions, thereby maintaining high precision without requiring complex optical correction elements
Solution Approach 2:
The patent replaces complex optical correction mechanisms with a simpler mechanical adjustment of distance. Instead of using additional optical elements to correct chromatic aberration, the system uses a drive mechanism to adjust the physical distance between camera and holding member, achieving precision correction through mechanical means
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
Achieves highly accurate imaging of components by suppressing chromatic aberration, ensuring precise component positioning and mounting.
Implementation Method 1
multiple light sources configured to emit lights of different wavelengths
Implementation Method 2
a camera configured to image an imaging target object irradiated by the lighting devices
Implementation Method 3
the proper value for the distance between the camera and the holding member is obtained for the light or lights of the one or more light sources based on the image forming point on the optical axis which changes according to the longitudinal chromatic aberration
Data Source
Figure 1
Figure 2
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AI summary
An imaging unit of the disclosure includes: a camera; a holding member configured to hold an imaging target object to be imaged by the camera; a light irradiation device configured to irradiate lights of different wavelengths from multiple light sources towards the imaging target object held by the holding member; and a control device configured to obtain a proper resolving power value for a light or lights of one or more light sources selected from the multiple light sources for use for imaging, irradiate the light or lights of the one or more light sources so selected onto the imaging target object to image the imaging target object using the camera, and make use of the proper resolving power value in processing an image obtained from the camera.