PROJECTION LENS

WIPO Patent Application WO/2019/114232

A1

Disclosed is a projection lens. The projection lens, along an optical axis from an image source side to an imaging side, sequentially comprises: a first lens having positive focal power; a second lens having negative focal power, surfaces of the image source side and the imaging side of the second lens being both concave surfaces; a third lens having positive focal power or negative focal power; and a fourth lens having positive focal power, the surface of the imaging side of the fourth lens being a convex surface. The total effective focal length f of the projection lens and the effective focal length f1 of the first lens satisfy an inequation: 2.0