zoom lens

Abstract

The present invention discloses a zoom lens capable of correcting aberrations well and forming imaging corresponding to the characteristics of a solid-state imaging element, which is compact and lightweight. The zoom lens consists of a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, a fourth lens group with positive refractive power, and a fourth lens group with negative refractive power in order from the object side. The fifth lens group of the refractive power constitutes, when the zoom lens changes the magnification from the wide-angle end to the telephoto end, the above-mentioned first lens group, the above-mentioned third lens group and the above-mentioned fifth lens group are fixed, the above-mentioned second lens group, the above-mentioned The fourth lens group moves on the optical axis, the aperture stop is fixed to the third lens group, and a predetermined conditional expression is satisfied.

Description

technical field [0001] The present invention relates to a zoom lens that is small and lightweight, well corrects aberrations, and has good resolution performance. Background technique [0002] In recent years, imaging devices equipped with solid-state imaging devices such as CCDs and CMOSs ​​have spread rapidly in a wide range of fields such as single-lens reflex cameras, digital still cameras, video cameras, surveillance cameras, and the like. Along with this, the need for lenses corresponding to solid-state imaging elements that have been developed to increase pixel count and increase sensitivity has gradually increased. [0003] In recent years, bright lenses with higher resolution have been demanded in imaging devices equipped with solid-state imaging devices that have been developed to increase pixel count and increase sensitivity. In addition, not only is there a strong demand for miniaturization of imaging devices, but also miniaturization and weight reduction of ima...

AI Technical Summary

Problems solved by technology

[0013] The zoom lens proposed in Patent Document 1 etc. has a structure suitable for a telephoto system, but when it is applied to a wide-angle system, it is difficult to correct aberrations such as curvature of field and chromatic aberration that occur when the angle of view increases

In addition, when it is applied to an optical system with a wide angle and a large aperture ratio, the ratio of the focal lengths shown in the embodiment of the second lens group and the fourth lens group cannot be based on the function of correcting the aberration accompanying the magnification change. , aberration correction is sufficiently performed from the wide-angle end to the telephoto end, making it difficult to achieve high performance

[0014] In the zoom lens proposed in Patent Document 2, etc., when the aperture is enlarged, it is difficult to correct the spherical aberration accompanying the enlargement of the aperture, and the number of lenses in the fifth lens group is small, so it is difficult to achieve a large aperture at the same time. and high performance

[0015] In the zoom lens proposed in Patent Document 3, etc., it is difficult to correct aberrations that occur when widening the angle, and it is difficult to achieve further widening and high resolution.

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