Optical system
An optical system includes: a first lens having refractive power; a second lens having refractive power; a third lens having refractive power and comprising an image-side surface which is convex in a paraxial region; a fourth lens having refractive power; a fifth lens having refractive power and comprising an image-side surface which is concave in the paraxial region; a sixth lens having refractive power; and a stop disposed in front of an object-side surface of the first lens. The first to sixth lenses are sequentially disposed from an object side. A radius of the stop SD and an overall focal length of the optical system f satisfy: 0.2<SD/f<0.6. An aberration improvement effect and high degrees of resolution and brightness may be obtained.
1. An optical system comprising:
a first lens having positive refractive power, a convex object-side surface, and a convex image-side surface;
a second lens having negative refractive power, a convex object-side surface, and a concave image-side surface;
a third lens having refractive power;
a fourth lens having negative refractive power;
a fifth lens having negative refractive power, and a concave image-side surface; and
a sixth lens having positive refractive power,
wherein the first to sixth lenses are sequentially disposed from an object side.
2. The optical system of claim 1 , wherein v1-v2>20 is satisfied, where v1 is an Abbe number of the first lens, and v2 is an Abbe number of the second lens.
3. The optical system of claim 1 , wherein |v5-v6|>20 is satisfied, where v5 is an Abbe number of the fifth lens, and v6 is an Abbe number of the sixth lens.
4. The optical system of claim 1 , wherein the first lens has a convex object-side surface.
5. The optical system of claim 4 , wherein the first lens has a convex image-side surface.
6. The optical system of claim 1 , wherein the second lens has a convex object-side surface.
7. The optical system of claim 6 , wherein the second lens has a concave image-side surface.
8. The optical system of claim 1 , wherein the sixth lens has a convex object-side surface.
9. The optical system of claim 1 , wherein the first to sixth lenses are formed of plastic.
10. The optical system of claim 1 , wherein at least one or more inflection points are formed on at least one or both of an object-side surface and an image-side surface of the fifth lens.
11. The optical system of claim 1 , wherein at least one or more inflection points on at least one or both of an object-side surface and an image-side surface of the sixth lens.
12. The optical system of claim 1 , wherein at least one or both of an object-side surface and an image-side surface of each of the first to sixth lenses is aspherical.