Telecentric lens

Abstract

The invention relates to a telecentric lens. The telecentric lens sequentially comprises a first lens group with positive optical power, a second lens group with negative optical power, a third lens group with negative optical power, a fourth lens group with positive optical power, a fifth lens group with negative optical power, a turn-back prism, a diaphragm, a sixth lens group with positive optical power, a seventh lens group with negative optical power and an eighth lens group with positive optical power from an object side to an image side. According to the telecentric lens, the clear imaging of 12-mega pixels can be realized without obvious purple boundary and chromatic dispersion, and the image quality is clear and bright; by virtue of a movable combination manner of different lens groups, the variation of the magnifying power of lenses is realized; meanwhile, the telecentric lens can meet double telecentricity requirements in an object space and an image space, the object spacetelecentricity and the image space telecentricity can meet the standard of a common telecentric lens, and the extremely high telecentricity level is realized; and by utilizing a special turn-back prism combination, an coaxial light source can be remarkably improved, a central hot spot can be formed, and the imaging problem caused by a halo produced y the light source is avoided.

Description

technical field [0001] The invention relates to a technology in the field of optical devices, in particular to a telecentric lens. Background technique [0002] The telecentric lens is mainly designed to correct the parallax of traditional industrial lenses. It can keep the magnification of the obtained image unchanged within a certain range of object distance, which is very important for the situation where the measured object is not on the same object plane. application. In the prior art, telecentric lenses are mainly divided into object-space telecentric and image-space telecentric lenses. The feature of the object-space telecentric optical path is that the converging center of the object-space chief ray parallel to the optical axis is located at infinity in the object-space, which can eliminate The reading error caused by inaccurate focusing on the object side; the feature of the telecentric optical path on the image side is that the main rays of the image side are para...

AI Technical Summary

Problems solved by technology

A bi-telecentric lens refers to an imaging system that satisfies the characteristics of both the object-space telecentric optical path and the image-space telecentric optical path. It includes the common advantages of the two telecentric optical paths, so it is more difficult to design. Fixed magnification lens, and the telecentricity of the object space and the image space cannot meet high standards at the same time, and the prism design of the traditional telecentric lens causes the light source to form a bright spot in the center of the image plane, which interferes with the imaging quality of the lens

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