Telecentricity

Telecentricity is a magnification error in the depth direction of an object. It is said that the smaller the magnification error, the higher the telecentricity.
Telecentric lenses are used for various purposes such as dimension measurement, but it is very important to know the telecentricity of the lens before using it.
Since the principal ray of a telecentric lens is parallel to the optical axis of the lens, it is very useful for workpieces with different heights.
If the telecentricity is poor, the appearance will change between the edge and the center of the screen, and the depth and front in the height direction, and the effect of using the telecentric lens will not be obtained. To confirm the telecentricity, it is possible to confirm it relatively easily by using the work shown in the figure below.