Patent attributes
An image-forming lens set includes an aperture stop, a first lens with positive power, a second lens with negative power and a third lens, which are arranged from an object side order. The first lens has two opposite surfaces including a convex surface facing the object side, and at least one of the two opposite surfaces is a non-spherical surface. The second lens has two opposite surfaces including a concave surface facing the object side, and at least one of the two opposite surfaces of the second lens is a non-spherical surface. The third lens has negative refractive power becoming greater from a center to a periphery of positive refractive power. The third lens has two non-spherical opposite surfaces including a convex surface facing the object side. At least one of the first, second and third lenses is coated with a layer of optical film for filtering light.
