As a special form of telecentric lens, the "cannon barrel lens" is particularly distinctive in its appearance. Its barrel is usually long and thick, giving it a heavy, sturdy and durable feel. This design not only helps to accommodate more optical elements and mechanical structures to achieve the special imaging effect of a telecentric lens, but also enhances the stability and durability of the lens. Telecentric lenses are a special type of optical lens commonly used in measurement and inspection applications.

1. Telecentric optical path design

The design of telecentric lenses is based on the principle of telecentric light path. This means that the light rays always remain parallel to their main rays as they enter and leave the lens, regardless of the distance of the object. This design eliminates perspective errors and image distortion, ensuring accurate and repeatable measurements.
 

2. Cannon barrel construction

A cannon barrel is a form of construction for telecentric lenses, usually with a long, straight profile, similar to the barrel of a cannon. This construction helps to increase the optical length of the lens, thus improving the telecentric effect. The longer optical length allows for better correction of aberration and provides a sharper, more accurate image.

3. Objective and eyepiece

Telecentric lenses usually consist of an objective lens and an eyepiece. The objective lens is responsible for collecting light and focusing it onto the imaging plane, while the eyepiece is used to observe and measure the imaging. In a cannon barrel construction, the objective and eyepiece are usually designed to have the same optical center to ensure telecentricity.

4. Elimination of perspective errors

Due to the nature of the telecentric optical path, telecentric lenses are able to eliminate perspective errors. When an object is at a different distance, conventional lenses may cause the size and shape of the object to change in the image, which is detrimental to accurate measurement. However, telecentric lenses maintain the true size and shape of objects regardless of their position in front of the lens.

5. Highly Accurate Measurement

These features of telecentric lenses make them useful in high-precision measurement applications, such as in industrial inspection, machine vision and automation systems. They can be used to measure the size, shape, position and other critical parameters of a part, providing reliable and accurate measurements.

The optical principle of the cannon barrel is based on a telecentric light path design, which eliminates perspective errors and enables high-precision measurements through a special objective and eyepiece structure. Such lenses play an important role in various industrial and scientific fields, providing a reliable tool for precise inspection and measurement.