How to choose a suitable telecentric lens
When the inspection object encounters the following 6 conditions, it is best to use a telecentric lens:
1) When it is necessary to detect objects with thickness (thickness > 1/10 FOV diameter);
2) When it is necessary to detect objects that are not in the same plane;
3) When it is not clear what the distance from the object to the lens is;
4) When it is necessary to detect an object with an aperture and a three-dimensional shape;
5) When low distortion is required and the brightness of the image effect is almost identical;
6) When the defect is only illuminated in parallel in the same direction, it can be detected.
So how do you choose the right telecentric lens, or how to choose the right telecentric lens?
Mainly from the following aspects:
1) When it is necessary to detect objects with thickness (thickness > 1/10 FOV diameter);
2) When it is necessary to detect objects that are not in the same plane;
3) When it is not clear what the distance from the object to the lens is;
4) When it is necessary to detect an object with an aperture and a three-dimensional shape;
5) When low distortion is required and the brightness of the image effect is almost identical;
6) When the defect is only illuminated in parallel in the same direction, it can be detected.
So how do you choose the right telecentric lens, or how to choose the right telecentric lens?
Mainly from the following aspects:
- Detecting the size of the sample -----------the field of view of the lens
- Is there a limit on the size of the installed space? The working distance of the lens -------- the distance of the lens
- The external lighting method should be considered -------------- the aperture of the lens
- Pipeline workflow method, loading, screening, etc. - the dimensions of the lens
Field of view = chip size / magnification
In general, chip size and magnification are important indicators of telecentric lenses, and each parameter has a description of this parameter.
Therefore, you only need to select the appropriate parameters according to the size of the workpiece you need to measure.
In the case of the same chip size, the larger the magnification, the smaller the field of view, the higher the precision; the magnification of some lenses is variable, meaning that the angle of view is also variable.
For example: optical magnification = 0.8X, CCD1/2 〃 (length 4.8mm × width 6.4mm)
Field of view size: length = 4.8 / 0.8 = 6 (mm) width = 6.4 / 0.8 = 8 (mm)
In general, chip size and magnification are important indicators of telecentric lenses, and each parameter has a description of this parameter.
Therefore, you only need to select the appropriate parameters according to the size of the workpiece you need to measure.
In the case of the same chip size, the larger the magnification, the smaller the field of view, the higher the precision; the magnification of some lenses is variable, meaning that the angle of view is also variable.
For example: optical magnification = 0.8X, CCD1/2 〃 (length 4.8mm × width 6.4mm)
Field of view size: length = 4.8 / 0.8 = 6 (mm) width = 6.4 / 0.8 = 8 (mm)
Common industrial camera sensor size 1/4": 3.2mm × 2.4mm; 1/3": 4.8mm × 3.6mm; 1/2": 6.4mm × 4.8mm; 2 / 3": 8.8mm × 6.6mm ;1′′: 12.8mm×9.6mm
Working distance
The working distance is another important parameter of the telecentric lens, and you can choose according to the actual installation size.
Aperture
Working distance
The working distance is another important parameter of the telecentric lens, and you can choose according to the actual installation size.
Aperture
The aperture will affect the depth of field. The larger the aperture, the worse the depth of field and the better the light. The smaller the aperture, the better the depth of field and the worse the light.
If your workpiece height difference is large and there are good lighting conditions, you can choose a lens with a small aperture. Anyway, choose a lens with a large aperture.
If your workpiece height difference is large and there are good lighting conditions, you can choose a lens with a small aperture. Anyway, choose a lens with a large aperture.