Wide-angle lens

Abstract

The invention discloses a wide-angle lens. The wide-angle lens comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens sequentially from the object side to the image side. The first lens is a plastic aspherical lens with negative refraction power, the second lens is a biconvex plus lens with a plastic aspherical lens, the third lens is a glass spherical lens with positive refraction power, the fourth lens is a plastic aspherical lens with negative refraction power, the fifth lens is a plastic aspherical lens, and focal power of all the lens satisfies the condition that f5<f2<f1<f3<f4, wherein f1, f2, f3, f4 and f5 are focal power of the first, second, third, fourth and fifth lens respectively. The first lens and the second lens collect wide-angle rays by adopting a minus lens and plus lens combination mode, so that an included angle between an off-axis primary ray and an optical axis can be reduced; due to the large focal power of the third lens, thermal shift can be corrected by the aid of the glass material, focal length change generated by temperature shift can be compensated effectively, and the problem of thermal shift caused when the lens is applied to severe environments at high and low temperature and the like is solved.

Description

technical field [0001] The invention belongs to the technical field of photographic devices, and in particular relates to a wide-angle lens. Background technique [0002] As wide-angle lenses are used in more and more fields, some application fields need to apply them in harsh environments such as high temperature or low temperature. Since the current lenses are mainly made of plastic structures, high and low temperatures will have a great impact on lenses with general plastic structures. Focus shift, which will affect the quality of imaging, serious imaging blur, unstable system parameters, failure modes such as failure to work properly. [0003] Because the refractive index of glass material changes little with temperature, it can well eliminate the influence of temperature on the focal length of the system. Therefore, a large number of glass materials are often used to solve the problem of thermal offset. However, due to the characteristics of glass materials, a large num...

AI Technical Summary

Problems solved by technology

[0004] In order to solve the problem that the existing wide-angle lens is easily deformed by using a large number of glass materials in order to adapt to the harsh environment of high and low temperature, a wide-angle lens is proposed, which reduces the use of glass materials, can adapt to the harsh environment of high and low temperature, and can also eliminate Effects of thermal excursion on the system

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