Tubular lens of image recognition system and image recognition system employing tubular lens

Abstract

The invention discloses a tubular lens of an image recognition system. The tubular lens is used for cooperating with an object lens; the focal distance of the tubular lens is f; the tubular lens comprises a first lens group, a second lens group and a third lens group; a diaphragm can be flexibly arranged; the focal distance of the first lens group f1 is greater than 0.7f, but smaller than 1.2f, and the effective clear aperture of the first lens group is greater than 0.1f; the focal distance of the second lens group f2 is greater than 0, but smaller than 0.2f; the focal distance of the third lens group f3 is greater than -5f, but smaller than -2f; an interval between the first lens group and the second lens group on an optical axis is smaller than 0.05f; an interval between the second lens group and the third lens group on the optical axis is greater than 0.25f. According to the tubular lens, the first lens group adopts a lens made of a material with large clear aperture and high refractivity as a light beam constraining lens, so that a large-visual field light beam under a large interval can be effectively constrained; furthermore, the second lens group and the third lens group can compensate and optimize light rays, so that aberration is corrected and an image space visual field is controlled, and thus the requirement of high-quality imaging, in which the interval can be increased and the lens can be varied, is ultimately met.

Description

technical field [0001] The invention relates to the field of optical imaging, and an image recognition system applied to semiconductor measuring equipment, in particular to a tube mirror of the image recognition system and an image recognition system with the tube mirror. Background technique [0002] The development of semiconductor measurement equipment is a high-tech industry that is rapidly developing in China, involving many advanced frontier scientific fields. Image recognition technology is also an indispensable part of semiconductor measurement equipment. It mainly pursues high-resolution, low-distortion imaging quality in order to quickly and accurately identify images. [0003] The optical part of the image recognition system is mainly composed of two parts: the objective lens and the tube lens. At present, domestic and foreign image recognition systems use tube lenses ranging from two lenses to four or five lenses, which can achieve high resolution (1001p / mm and ...

AI Technical Summary

Problems solved by technology

[0009] If the existing design of the objective lens and tube lens is adopted, blindly elongating the imaging distance will result in reduced image resolution, uneven illumination, serious edge vignetting, etc., which will affect the accuracy of image recognition

If the imaging distance of objective lenses of different magnifications is also required to be adjustable at the same time, it cannot meet the requirements, because in general, when the imaging quality of an objective lens of one magnification is guaranteed, the imaging quality of another objective lens of different magnifications will be greatly reduced.

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