Optical lens with stable imaging quality

The invention relates to an optical lens with stable imaging quality, which adopts a fixed aperture and diffraction limit design thought to improve the resolution of the lens. The first lens group, the second lens group, the diaphragm, the third lens group and the fourth lens group are sequentially arranged in the lens cone from the object side to the image side. The first lens group and the fourth lens group are arranged to be single lenses, the second lens group and the third lens group are arranged to be glued lenses, and the diaphragm is arranged at the focal plane position of the second lens group and located at the object plane position of the third lens group. The glued lens can be used for achromatic change of image quality, and the single lens can give full play to the refraction effect of the single lens on an optical path, and can play a great role in enlarging the field of view. And the diaphragm is arranged at the focal plane position of the second lens group and is located at the object plane po