Lens

Abstract

The invention provides a lens. In the embodiment of the invention, four lens groups are sequentially arranged in the lens from an object side to an image side according to a specific sequence, and thelens groups in the lens satisfy the following conditions: 1.21 < = f1 / f '< = 1.41 and 2.25 < = TTL / ((BFL * f ') 1 / 2) < = 2.65; f1 is the focal length of the first lens group; f'is the focal length ofthe lens; TTL is the total optical length of the lens; and BFL is the distance between the fourth lens group and the image plane. The size of the target surface of the lens and the aperture are increased to a certain extent, so that the resolution of the acquired image is high, the light transmission amount of the lens can still be ensured in a low-illumination scene, the quality of the acquiredimage is good, and the total optical length of the lens is reduced. Therefore, the embodiment of the invention provides the lens which is small in size, large in target surface size and large in aperture.

Description

technical field [0001] The invention relates to the technical field of optical imaging, in particular to a lens. Background technique [0002] With the development of society, people's awareness of safety precautions has been continuously improved, and the security monitoring industry has also developed rapidly, and the role of monitoring is becoming more and more important. At present, monitoring fixed-focus lenses are widely used in people's daily life, but conventional security monitoring and road condition monitoring lenses have the following disadvantages: [0003] Most of the lens structure is simple, and the size of the target surface is small, resulting in low resolution of the collected images, general shooting effect, and little picture value. Moreover, most of the zoom lenses currently on the market have small apertures, resulting in less light transmission through the lens, and darker images acquired in low-light scenes, making it difficult to guarantee image qu...

AI Technical Summary

Problems solved by technology

[0003] Most of the lens structure is simple, and the size of the target surface is small, resulting in low resolution of the collected images, general shooting effect, and little picture value

Moreover, most of the zoom lenses currently on the market have small apertures, resulting in less light transmission through the lens, and darker images acquired in low-light scenes, making it difficult to guarantee image quality.

Images