Telecentric lens is mainly designed to correct the parallax of traditional industrial lens. It can be within a certain object distance range, so that the magnification of the obtained image will not be changed. Telecentric lenses have always been favored by machine vision applications that require high lens distortion due to their unique parallel light path design.

Principle advantage

The purpose of the design of the telecentric lens is to eliminate the difference in magnification due to the inconsistency of the distance between the measured object (or CCD chip) and the lens. According to the classification and design principles of telecentric lenses, there are 3 types:

1) Oobject-side telecentric lens:

The object-side telecentric optical path is to place the aperture diaphragm on the image-side focal plane of the optical system, and the object-side principal ray is parallel to the optical axis and the convergence center of the principal ray is located at infinity on the image side, which is called: the object-side telecentric optical path. Its function is: it can eliminate the reading error caused by the inaccurate focusing of the object.

2) Image side telecentric lens:

The image-side telecentric optical path is to place the aperture diaphragm on the object-side focal plane of the optical system, and the image-side principal ray is parallel to the optical axis and the convergence center of the principal ray is located at infinity on the object side, which is called: image-side telecentric optical path. Its function is: it can eliminate the measurement error caused by inaccurate focusing on the image side.

3) Bi- telecentric lens:

It combines the dual functions of the object-side/image-side telecentricity. Mainly used in the field of visual measurement and inspection.