Patent ID: 7375907

Claim:
A lens system for a digital camera, comprising, in order from an object side to an image side: a first lens element being biconvex, the first lens element comprising a first spherical surface and a second spherical surface, the first spherical surface facing toward the object side, the second spherical surface facing toward the image side, the first lens element made of glass; a second lens element being concavo-convex, the second lens element comprising a first aspheric surface and a second aspheric surface, the first aspheric surface being a diffractive concave surface facing toward the object side, the second aspheric surface facing toward the image side, the second lens element being made of plastic; and a third lens element comprising a third aspheric surface and a fourth aspheric surface, the third aspheric surface facing toward the object side, the fourth aspheric surface facing toward the image side, the third and fourth aspheric surfaces being wave-shaped, the third lens made of plastic; wherein the first spherical surface and the second spherical surface of the first lens element, the second aspheric surface of the second lens element, and the third aspheric surface and the fourth aspheric surface of the third lens element each are a refractive surface.