Patent ID: 7468847
Filing Date: 2008-12-23
Classification: G02B

Abstract:
1. An optical lens system for taking image comprising three lens elements with refractive power, from the object side to the image side: a first lens element with positive refractive power having a convex surface on the object side and a concave surface on the image side, at least one of the object-side surface and the image-side surface of the first lens element being aspheric; a plastic second lens element with negative refractive power having a concave surface on the object side and a convex surface on the image side, the object-side surface and the image-side surface of the second lens element being aspheric; a plastic third lens element with positive refractive power having a convex surface on the object side and a concave surface on the image side, the object-side surface and the image-side surface of the third lens element being aspheric; and an aperture stop located in front of the first lens element for controlling brightness of the optical lens system; wherein a focal length of the second lens element is f