Projection lens and display system

The invention discloses a projection lens and a display system. The projection lens comprises a display device, a lens assembly and an aperture diaphragm which are sequentially arranged in a preset direction; the lens assembly comprises a plurality of lenses arranged in the preset direction. Wherein 6 mm < = f < = 10 mm, 26 degrees < = FOV < = 40 degrees, 3 mm < = h < = 6 mm, 4 mm < = R < = 10 mm, 9 mm < = L < = 15 mm; f is the focal length of the lens assembly, FOV is the field angle of the lens assembly, h is the aperture of the aperture diaphragm, R is the aperture of the lens assembly, and L is the distance between the display device and the aperture diaphragm in the preset direction AA. According to the projection lens, various aberrations of the projection lens can be effectively corrected by reasonably designing various parameters of the lens assembly and the aperture diaphragm and adjusting the distance between the lens assembly and the aperture diaphragm, so that the projection lens has the advantage