Patent ID: 8482863

Claim:
An imagery optical system, sequentially arranged from an object side to an image side, comprising: a first lens element with positive refractive power; a second lens element with positive refractive power; a third lens element; a fourth lens element having a concave object-side surface and a convex image-side surface, and at least one of the object-side and image-side surfaces being aspheric; a fifth lens element made of plastic, and having at least one of object-side and image-side surfaces being aspheric, and at least one of the object-side and image-side surfaces having at least one inflection point; wherein, an axial distance between the third lens element and the fourth lens element is T 34 , an axial distance between the fourth lens element and the fifth lens element is T 45 , a curvature radius of the image-side surface of the second lens element is R 4 , a curvature radius of the object-side surface of the third lens element is R 5 , an Abbe number of the first lens element is v 1 , an Abbe number of the third lens element is v 3 , and the following relations are satisfied: 0.1 <T 45 /T 34 <2.0; −3.0 <R 4 /R 5 <0.7; and 28.0 <v 1 −v 3 .