Continuous zoom telecentric lens

Abstract

A telecentric lens with continuous variable magnification belongs to the technical field of machine vision. From the object plane to the image plane, the continuously zooming telecentric lens is: lens group A with positive refractive power, lens group B with negative refractive power, system aperture stop and lens group C with positive refractive power; , lens group A includes a first lens with positive refractive power, a second lens with positive refractive power and a third lens with negative refractive power, lens group B includes a fourth lens with negative refractive power, a fourth lens with negative optical power A fifth lens with a power and a sixth lens with a negative power, the lens group C includes a seventh lens with a negative power, an eighth lens with a positive power, and a ninth lens with a positive power; the lens The positions of group A, lens group C, system aperture diaphragm and image plane are fixed, and lens group B as a whole can move back and forth relative to the system aperture diaphragm. The invention has the advantages of less lens quantity and groups, simple cam curve and the like.

Description

technical field [0001] The invention relates to a technology in the field of machine vision, in particular to a continuously zooming telecentric lens. Background technique [0002] In industrial inspection, it is sometimes necessary to use the same measurement system to measure objects of different sizes with high precision. At this time, neither the traditional fixed-focus lens nor the fixed-power telecentric lens can meet the demand. The zoom telecentric lens can not only continuously change the magnification to meet the requirements of different fields of view, but also its high resolution, low optical distortion and low telecentricity can also meet the measurement accuracy requirements. [0003] However, in the existing products and technologies, the structure of the zoom telecentric lens is relatively complicated, which is manifested in the following two points: (1) the number of lenses is large (generally ≥14 pieces), and the number of lens groups is large (generally ≥...

AI Technical Summary

Problems solved by technology

[0003] However, in the existing products and technologies, the structure of the zoom telecentric lens is relatively complicated, which is manifested in the following two points: (1) the number of lenses is large (generally ≥14 pieces), and the number of lens groups is large (generally ≥4 group), resulting in higher cost; (2) The continuous zoom function is realized by the cooperation of the fixed lens group, the zoom group and the compensation group. Usually the moving steps of the zoom group and the compensation group are not consistent, which requires the cam Design two different curves on the above; if there are more zoom groups or compensation groups, multiple cam curves or multiple cam structures may be required; more complex zoom implementation methods will magnify the subtle problems of the system, resulting in more Uncertainty

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