Low-distortion fisheye lens

Abstract

The invention belongs to the field of lenses, and particularly relates to a low-distortion fisheye lens which comprises a first lens with convex-concave negative focal power, a second lens with convex-concave negative focal power, a third lens with biconcave negative focal power, a fourth lens with biconvex positive focal power, a fifth lens with biconvex positive focal power, a sixth lens with biconvex positive focal power, a seventh lens with concave-convex negative focal power, and an eighth with biconvex positive focal power which are sequentially arranged from an object side to an image side. The lenses are all glass lenses, the first to seventh lenses are glass spherical surfaces, and the eighth lens is a glass aspheric surface. The sixth lens and the seventh lens are doublet lenses.Through the use of the doublet lenses and the glass aspheric surface, the focal power is reasonably distributed, the F-Theta distortion is as small as 0.8%, the total optical length is shortened to 16.7 mm, the light ray trend is gentle, the aberration correction is good, defocusing does not occur in high and low temperature environments of -40 DEG C to 85 DEG C, and the resolution remains unchanged in a large field of view of 190 degrees.

Description

technical field [0001] The invention belongs to the field of monitoring lenses, in particular to a low-distortion fisheye lens. Background technique [0002] In recent years, because of its large field of view, fisheye lenses can achieve full spatial inclusion and full-time real-time information acquisition, and more people have been used in scene monitoring. However, because of its large field of view and short focal length , making the image formed by it quite deformed, which is commonly known as distortion in optics. The traditional all-glass fisheye lens has a lot of distortion due to the inherent properties of the fisheye lens. The present invention uses an aspherical glass lens, combined with the use of a doublet lens, effectively reduces the distortion of the fisheye lens, and by rationally distributing the optical power, the present invention has a large field of view of 190° Under normal circumstances, the F-Theta distortion is as small as 0.8%, the total optical ...

AI Technical Summary

Problems solved by technology

[0002] In recent years, because of its large field of view, fisheye lenses can achieve full spatial inclusion and full-time real-time information acquisition, and more people have been used in scene monitoring. However, because of its large field of view and short focal length , making the image formed by it quite deformed. This deformation is commonly known as distortion in optics.

The traditional all-glass fisheye lens has a large distortion due to the inherent properties of the fisheye lens

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