Patent ID: 8599498

Claim:
An optical lens assembly for image taking, sequentially arranged from an object side to an image side, comprising: a first lens element with positive refractive power, having a convex object-side surface; a second lens element with negative refractive power, having a convex object-side surface and a concave image-side surface; a third lens element with positive refractive power, having a convex image-side surface; a fourth lens element with refractive power, having both object-side surface and image-side surface being aspheric; and a fifth lens element with negative refractive power, having a concave object-side surface, and both object-side surface and image-side surface being aspheric; wherein f is a focal length of the optical lens assembly for image taking, f 1 is a focal length of the first lens element, f 2 is a focal length of the second lens element, f 3 is a focal length of the third lens element, f 4 is a focal length of the fourth lens element, R 3 is a curvature radius of the object-side surface of the second lens element, R 4 is a curvature radius of the image-side surface of the second lens element, R 5 is a curvature radius of the object-side surface of the third lens element, R 6 is a curvature radius of the image-side surface of the third lens element, and the following relations are satisfied: 0.7< f/f 1 <2.5; −2.5< f/f 2 <−0.7; 0.8< f/f 3 <2.5; −0.7< f/f 4< 0.5; 0.05<( R 3 −R 4 )/ R 3 +R 4 )<0.8; 0.1<( R 5 +R 6 )/( R 5 −R 6 )<1.5.