In the optical system, telecentric lens is a kind of lens with special optical path design, whose optical path design can effectively eliminate aberration and distortion, thus providing more accurate images. Telecentric lens optical path type is mainly divided into object-square telecentric, image-square telecentric and double telecentric and other types, each type of optical path has its unique characteristics and advantages.
First, the object-square telecentric lens
The design of the object-square telecentric lens is characterized by the aperture diaphragm is placed in the optical system like the square focal plane, while the object-square main light is parallel to the optical axis of the main light convergence centre is located in the object-square infinity. The main advantage of this type of optical path design is that it eliminates object-side reading errors due to inaccurate focusing.
The object-side telecentric lens is more adaptable to the distance of the object, whether the object is far from the lens is close, can get a clear image. At the same time, due to the object side of the main ray parallel to the main ray of the optical axis, so can effectively avoid the image distortion due to light tilt.
Second, like a square telecentric lens
Like a square telecentric lens design features, the aperture diaphragm is placed in the optical system of the object side of the focal plane, and like the main light is parallel to the optical axis of the main light convergence centre is located in the image of the infinite distance. The main advantage of this type of optical path design is the elimination of measurement errors introduced by inaccurate focusing on the image side.
The optical path of the image-side telecentric lens is designed so that the light rays from the image-side pass through the lens and converge into a clear image in the object-side. This imaging method makes the lens more sensitive to changes in the position of the image, you can more accurately measure the position and size of the object.
Third, double telecentric lens
Double telecentric lens combines the dual role of the object side / image side, the main light is not only in the lens is parallel, in the outgoing is also parallel. In addition, double telecentric lens in the direction of the optical axis of the projected image will not be deformed, so that in the measurement can ensure higher accuracy.
When choosing to use telecentric lenses, you need to choose according to the specific application scenarios and needs. At the same time, it is also necessary to consider the focal length of the lens, aperture, interface type and other factors to ensure that the selected lens can meet the actual needs.
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