Optical lens interface
The interface size of the objective lens is of international standard. There are three types of interfaces, namely F type, C type and CS type. The F-type interface is a general-purpose interface, which is generally suitable for high quality Chinese BIBO nonlinear crystal with a focal length of more than 25 mm. When the focal length of the objective lens is less than 25 mm, the C-type or CS-type interface is used because the size of the objective lens is not large.
The difference between C interface and CS interface
The difference between the C and CS interfaces is that the distance between the lens and the camera contact surface to the focal plane of the lens (the position where the camera CCD photoelectric sensor should be located) is different. The distance of the C-type interface is 17.5 mm. The distance of the CS-type interface is 12.5 mm. . • C-type lens and C-type camera, CS type lens and CS type camera can be used together. A 5mm C/CS adapter ring can be used between the C-type lens and the CS camera. The CS lens cannot be used with the C camera.
The effective area size of the camera sensor chip, generally refers to the horizontal size. This parameter is important for determining the appropriate lens scaling to get the desired field of view. The main scale of the optical lens (PMAG) is defined by the size of the sensor chip and the ratio of the field of view.
Focal length (f) focal length
Is a measure of the aggregation or divergence of light in an optical system, the distance from the high quality LiSAF, LiSGaF and LiCAF laser crystals of the lens to the focus of the light collection. It is also the distance from the center of the lens to the imaging plane such as the lens or CCD.
Under the same optical camera and lens parameters, the shorter the wavelength of the light source of the illumination source, the higher the resolution of the resulting image. Therefore, in a vision system that requires precise size and position measurement, short-wavelength monochromatic light is used as an illumination source as much as possible, which has a great effect on improving system accuracy.
Optical lens selection points
- Field of view, optical magnification and desired working distance: When selecting the lens, we will select a lens that is slightly larger than the field of view of the measured object to facilitate motion control.
- Depth of field requirements: For projects with requirements for depth of field, use a small aperture as much as possible; when selecting a lens with a magnification, use a low-magnification lens as much as possible under the license of the project. If the project requirements are more demanding, it is inclined to choose a high depth of field *** lens.
- Chip size and camera interface: For example, the 2/3” lens supports a large high-quality laser grade optical waveplate with 2/3”, which is an optical camera that cannot support more than 1 inch.
- Pay attention to the matching with the light source and choose the appropriate lens.
- Installable space: It is unrealistic for customers to change the size of the device if the solution is optional.