Posted March 12, 2019 at 2:47 am by xzbbvfvbh

Optical lens selection

The optical lens is mainly designed to correct the parallax of the conventional large size YVO4 laser crystal. It can make the image magnification not change within a certain object distance range. This is very important for the case where the measured object is not on the same object surface. application. Telecentric lenses have always been favored for machine vision applications where lens distortion is critical due to their unique parallel light path design.

Optical lenses are important imaging components in machine vision systems. If the system wants to fully function, the optical lens must be able to meet the requirements. At the beginning of the 21st century, with the wide application of machine vision systems in the field of precision inspection, ordinary optical lenses are difficult to meet the testing requirements. To meet the shortcomings of ordinary lens applications, and to meet the needs of precision detection, telecentric lenses have emerged.

Optical lenses are based on their unique optical properties: high resolution, ultra-wide depth of field, ultra-low distortion and unique parallel light design, which brings a qualitative leap to machine vision precision inspection.

When choosing a telecentric lens, customers should first understand when to choose a telecentric lens when needed. According to the principle characteristics and unique advantages of the telecentric lens, when the inspection object encounters the following 6 conditions, the better choice is to use the telecentric lens:

(1) When it is necessary to detect an object having a thickness (thickness > 1/10 FOV diameter);
(2) When it is necessary to detect objects that are not in the same plane;
(3) When it is not clear what the distance from the object to the lens is;
(4) When it is necessary to detect an object with an aperture and a three-dimensional shape;
(5) When low distortion is required and the brightness of the image effect is almost identical;
(6) When the defect is detected only in parallel illumination in the same direction.

The optical lens is mainly designed to correct the parallax of the conventional high precision YVO4 laser crystal. It can be within a certain object distance range, so that the image magnification will not change with the object distance, which is not the same in the object to be tested. The situation on the surface is a very important application.

The closer the target object of a normal optical lens is to the lens (the shorter the working distance), the larger the image will be. When using a normal lens for dimensional measurement, there are the following problems:

(1) The difference in magnification is caused because the objects to be measured are not in the same measurement plane;
(2) Large lens distortion
(3) Parallax means that when the object distance becomes larger, the magnification of the object also changes;
(4) The resolution of the lens is not high;
(5) Uncertainty of the edge position of the image due to the geometrical characteristics of the visual source.

The telecentric lens can effectively solve the above problems of the ordinary lens, and there is no judgment error of this nature, so it can be used in high-precision measurement, measurement and measurement, and the like. The telecentric lens is a high-end wholesale YLF laser crystal that usually has superior image quality and is especially suitable for dimensional measurement applications.

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