Optical system

Abstract

An optical system includes a first lens having refractive power; a second lens having refractive power, both surfaces thereof being convex in a paraxial region; a third lens having refractive power and having an object-side surface that is convex in the paraxial region; a fourth lens having refractive power; a fifth lens having refractive power and having an image-side surface that is concave in the paraxial region; and a sixth lens having refractive power, wherein the first to sixth lenses are sequentially disposed from an object side, and when an Abbe number of the first lens is v1 and an Abbe number of the second lens is v2, |v1−v2|<10 is satisfied, whereby an aberration improvement effect can be increased, and high resolution in images captured thereby can be realized while an amount of light incident through the lenses to an image sensor can be increased.

What is claimed is: 
     
         1 . An optical system comprising:
 a first lens comprising positive refractive power, a convex object-side surface and a concave image-side surface;   a second lens comprising a convex object-side surface;   a third lens comprising negative refractive power, a convex object-side surface and a concave image-side surface;   a fourth lens comprising positive refractive power;   a fifth lens comprising refractive power; and   a sixth lens comprising negative refractive power and a concave image-side surface,   wherein the first to sixth lenses are sequentially disposed from an object side to an image side, and   wherein TTL/f<1.35 is satisfied, where TTL is a distance from the object-side surface of the first lens to an imaging surface of an image sensor, and f is an overall focal length of the optical system.   
     
     
         2 . The optical system of  claim 1 , wherein −30<(r9−r10)/(r9+r10)<3 is satisfied, where r9 is a radius of curvature of an object-side surface of the fifth lens, and r10 is a radius of curvature of the image-side surface of the fifth lens. 
     
     
         3 . The optical system of  claim 1 , wherein v1−v3>30 is satisfied, where v1 is an Abbe number of the first lens, and v3 is an Abbe number of the third lens. 
     
     
         4 . The optical system of  claim 1 , wherein 0.01<|f/f5|<0.07 is satisfied, where f5 is a focal length of the fifth lens. 
     
     
         5 . The optical system of  claim 1 , wherein the fourth lens comprises a concave object-side surface and a convex image-side surface. 
     
     
         6 . The optical system of  claim 1 , wherein the fifth lens comprises a concave image-side surface. 
     
     
         7 . The optical system of  claim 1 , wherein the sixth lens comprises a convex object-side surface.