【Telecentric lens】features of telecentric lens

In: Lens Wiki On: Wednesday, April 8, 2020 Hit: 1962

Telecentric lens is a kind of lens with excellent performance. It usually has high central edge consistency, very low distortion and close to the diffraction limit of optical resolution. So why do telephoto lenses perform so well?

To understand this, you first need to understand the principle of telephoto lenses, which are generally divided into three categories: object telephoto, image telephoto, and double telephoto. This paper mainly describes the matter of distance, the other two kinds of principle is similar.

Figure 1 is a schematic diagram of object side telecentric, mainly composed of three parts: the front lens group (focal length of 100mm), the rear lens group (focal length of 75mm), and the aperture aperture in the middle. The object plane and the aperture aperture are located in the front and rear focal plane of the front lens respectively. At this time, the lens' entrance pupil is located at infinite distance, which determines its property of object's distance center. In particular, if the aperture aperture and the image plane are located in the front and rear focal plane of the rear lens respectively, it is a double telecentric lens.

Figure 1: ideal object telecentric lens system

In the optical path diagram, you can judge which kind of telecentric type is by the position relation between the main ray and the optical axis. The main ray of the object side telecentric lens (the center line of each color group) is parallel to the optical axis in the object space, but the main ray and the optical axis are included angles in the image space.

Says below telecentric lens depth of field characteristics, because the telecentric lens aperture is small, lead to the incoming light Angle is small, the approximate parallel to the incident light, the parallel light, object plane back and forth motion theory does not cause the change of like, but the size of aperture, after all, there is some, so also have a range of mobile. This moving range is also known as the depth of field.

The telecentric degree of our telecentric lens can reach 0.01°, the distortion is less than 0.05%, the resolution and contrast are excellent, the supporting camera target surface covers 1/3 '" to 1.75 ", the multiplier is complete, the working distance is reasonable, by the customer's wide praise, welcome the customer to deion.

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