Patent ID: 8179616

Claim:
An optical lens assembly for image taking, sequentially arranged from an object side to an image side, comprising: a first lens element with refractive power; a second lens element with positive refractive power; a third lens element with negative refractive power, having a concave object-side surface and a convex image-side surface, and at least one of the object-side surface and image-side surface of the third lens element being aspheric; a fourth lens element with positive refractive power, having a convex object-side surface, and at least one of the object-side surface and an image-side surface of the fourth lens element being aspheric; wherein the optical lens assembly for image taking further comprises a stop; wherein, CT 3 is a thickness of the third lens element near the optical axis, CT 4 is a thickness of the fourth lens element near the optical axis, f is a focal length of the optical lens assembly for image taking, EPD is an entrance pupil diameter of the optical lens assembly for image taking, and the following relations are satisfied: 0.5 <CT 3 /CT 4 <1.5; f/EPD< 1.8.