As optical lenses are not very widely used, telecentric lenses have always been mysterious and not well-known. The design principles of telecentric lenses are introduced below.

The telecentric lens is a lens specially designed to correct the parallax of the traditional lens. It can be within a certain object distance range, so that the image magnification will not change with the change of the object distance. This is a very important application when the measured object is not on the same surface.

1. The principle and function of the object-side telecentric optical path design:

　　 The object-side chief ray is parallel to the optical axis chief ray The convergence center of is located infinitely far away from the image side, which is called the telecentric light path in the object side. Its function is: it can eliminate the reading error caused by the inaccurate focusing of the object.

　　2. Design principle and function of the image-side telecentric light path:

　　 The principal ray of the image side is parallel to the principal ray of the optical axis The convergence center of is located infinitely far away from the object, which is called: the telecentric light path of the image side. Its function is: it can eliminate the measurement error caused by the inaccurate focusing on the image side.

　　3. Design principle and function of the telecentric light path on both sides:

　　 integrates the object-side/image-side telecentric double effect. Mainly used in the field of vision measurement and inspection.

　　 It can be seen from the above design principles of various types of telecentric lenses that the telecentric lens is designed to make full use of the optical imaging characteristics and fully consider the influence of light in the imaging. High-precision lenses have been widely used in the field of machine vision precision measurement and high-precision detection.

Before polishing, it must be determined whether there are scratches or punctures left by the surface of the optical lens after polishing. Whether the size and material of the polishing tool are appropriate. Whether the hardness and thickness of the asphalt are appropriate. During the polishing process, attention must be paid to the condition and accuracy of the lens surface at all times. In the inspection of lens surface defects, because the inspection process is judged by personal vision and methods, the inspector should have a deep understanding of the specifications of scratches and sand holes, and often compare the standard samples of scratches and sand holes. To ensure the correctness of the inspection.