Answers to the eight questions about telecentric lens applications

Answers to the eight questions about telecentric lens applications

A telecentric lens is a high-end machine vision lens. Its purpose is to eliminate the difference in magnification caused by the inconsistent distance between the measured object (or CCD chip) and the lens. Divided into: object-side telecentric lens, image-side telecentric lens and bilateral telecentric lens three categories.

Due to the unique technical advantages of telecentric lenses, the current requirements for high-precision inspections such as mechanical part measurement, plastic part measurement, glass product and medical part measurement, and electronic component measurement are particularly suitable for precision measurement occasions. Today, China Machine Vision Mall

1. What are the advantages of a telecentric lens?

    The telecentric lens is designed using the Telecentric principle, with low distortion and no viewing angle error. The telecentric lens has another coaxial lens design, which provides different working distances and different magnifications to choose from.

2. Why is the price of a telecentric lens low?

    In order to reduce distortion and allow parallel light to enter, a telecentric lens must be larger than the subject. Therefore, low-power lenses usually have large apertures, and the cost of lens materials is higher, so the price is higher.

3. When the coaxial light lens plays coaxial light, the middle brightness is brighter and the whole side is darker. What is the reason? How to remedy?

    Because the projection light of the coaxial light lens is concentrated at about 5 ~ 6㎜ in the center, if the viewing range is large, the light near the edge is darker. This is a common phenomenon of low magnification coaxial light lenses. You can add a ring light source to make up for the lack of light.

4. Can telecentric lenses be used with CCTV 2x lenses?

    Yes, but the image quality deteriorates, and the required light intensity is stronger. It is not recommended.

5. In telecentric lens specifications, what does it mean to indicate the lens resolution (resolution)?

    The definition of the lens resolution is the ability of the lens to see the edge of the smallest object clearly. If it is lower than this resolution, it cannot be seen clearly. Look for lenses with higher resolution, such as high magnification microscope objectives.

6. Why can't the telecentric lens have a long depth of field?

    When designing a telecentric lens, the depth of field, magnification, aperture, working distance and other parameters are taken into consideration to obtain the best point. Therefore, the depth of field is a fixed value. If you want to increase the depth of field and sacrifice other parameters, it will affect the lens quality.

7. What kind of lens can I use if I want to see a 1μm object?

    To see objects smaller than 1 μm, a high magnification microscope objective must be used, but the working distance becomes very small (about 7㎜), and the depth of field becomes very shallow.

8. How many times is the image magnified with a telecentric lens?