Zoom lens and imaging device

Abstract

The invention relates to the field of optics, in particular to a zoom lens and an imaging device. The zoom lens sequentially comprises a first lens group with positive focal power, a second lens group with negative focal power, a third lens group with positive focal power, a fourth lens group with negative focal power and a fifth lens group with positive focal power from an object plane side to an image plane side, the zoom lens at least comprises four aspheric lenses; and the zoom lens satisfies the following conditional expressions: 1.5<FNO<4, 15<ft / fw<20, wherein fno is the number of apertures of the zoom lens, ft is the focal length of the telephoto end of the zoom lens, and fw is the focal length of the wide-angle end of the zoom lens. According to the invention, the influence of the environment temperature change on the zoom lens is reduced as much as possible, then the possibility of focal plane offset of the zoom lens is reduced, the possibility of image blurring of the zoom lens is reduced, and the imaging quality of the zoom lens is improved.

Description

technical field [0001] The invention relates to the field of optics, in particular to a zoom lens and an imaging device. Background technique [0002] A zoom lens is a lens that can change the focal length within a certain range, so as to obtain different wide and narrow field of view angles, different size images and different scene ranges. The zoom lens can change the shooting range by changing the focal length without changing the shooting distance. , so it is very conducive to the composition of the picture. [0003] With the increasing popularity of zoom lenses, it has played an important role in more and more fields such as surveillance and video communication. However, the current zoom lenses mainly use glass lenses, which is increasingly difficult to meet the growing cost of surveillance lenses. , low weight, high image quality requirements. [0004] Due to its physical and processing characteristics, plastic lenses can easily achieve low cost, low weight, and meet...

AI Technical Summary

Problems solved by technology

[0003]With the increasing popularity of zoom lenses, it has played an important role in more and more fields such as surveillance and video communication. However, the current zoom lenses use glass lenses It is increasingly difficult to meet the growing demand for low cost, low weight, and high image quality of surveillance lenses

[0004] Due to its physical and processing characteristics, plastic lenses can easily achieve low cost, low weight, and meet the requirements of high imaging quality. However, due to the large thermal expansion coefficient and refractive index temperature coefficient of plastic, the zoom lens of plastic lenses is used. Often the temperature drift is far greater than that of a zoom lens that only uses glass lenses, that is, when the ambient temperature changes, the focal plane will shift greatly, and the picture will often appear blurred during use, which reduces the imaging quality of the zoom lens

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