Optical imaging system
An optical imaging system includes a first lens having a concave image-side surface, a second lens having a concave image-side surface, and a third lens having a positive refractive power. The optical imaging system includes a fourth lens having a positive refractive power and a concave object-side surface, a fifth lens, a sixth lens having a positive refractive power, and a seventh lens having a concave object-side surface. The first lens to the seventh lens are sequentially disposed at intervals from an object side toward an imaging plane.
1. An optical imaging system, comprising:
a first lens comprising a positive refractive power and a concave image-side surface along an optical axis;
a second lens comprising a negative refractive power a concave image-side surface along the optical axis;
a third lens comprising a positive refractive power;
a fourth lens comprising a positive refractive power and a concave object-side surface along the optical axis;
a fifth lens comprising a negative refractive power;
a sixth lens comprising a positive refractive power; and
a seventh lens comprising a negative refractive power and a convex object-side surface along the optical axis,
wherein the first lens to the seventh lens are sequentially disposed from an object side toward an imaging plane.
2. The optical imaging system of claim 1 , wherein an object-side surface of the first lens is convex along the optical axis.
3. The optical imaging system of claim 1 , wherein an object-side surface of the second lens is convex along the optical axis.
4. The optical imaging system of claim 1 , wherein an object-side surface of the third lens is convex along the optical axis.
5. The optical imaging system of claim 1 , wherein an image-side surface of the third lens is concave along the optical axis.
6. The optical imaging system of claim 1 , wherein an object-side surface of the fifth lens is concave along the optical axis.
7. The optical imaging system of claim 1 , wherein an image-side surface of the fifth lens is convex along the optical axis.
8. The optical imaging system of claim 1 , wherein an object-side surface of the sixth lens is convex along the optical axis.
9. The optical imaging system of claim 1 , wherein an image-side surface of the sixth lens is concave along the optical axis.
10. The optical imaging system of claim 1 , wherein an image-side surface of the seventh lens is concave along the optical axis.
11. An optical imaging system, comprising:
a first lens comprising a positive refractive power and a concave image-side surface, a second lens comprising a negative refractive power, a third lens comprising a positive refractive power, a fourth lens comprising a positive refractive power and a concave object-side surface along the optical axis, a fifth lens comprising a negative refractive power, a sixth lens comprising a positive refractive power, and a seventh lens comprising a negative refractive power and a convex object-side surface along the optical axis, sequentially disposed from an object side toward an imaging plane,
wherein the optical imaging system satisfies the following Conditional Expression:
f 2/ f<− 2.0
where f represents an overall focal length of the optical imaging system and f2 is a focal length of the second lens.
12. The optical imaging system of claim 11 , wherein the optical imaging system satisfies the following Conditional Expression:
0< f 1/ f< 2.0
where f1 represents a focal length of the first lens.
13. The optical imaging system of claim 11 , wherein the optical imaging system satisfies the following Conditional Expressions:
25< V 1− V 2<45,
V 1− V 3<25, and
25< V 1− V 5<45
where V1 represents an Abbe number of the first lens, V2 represents an Abbe number of the second lens, V3 represents an Abbe number of the third lens, and V5 represents an Abbe number of the fifth lens.
14. The optical imaging system of claim 11 , wherein the optical imaging system satisfies the following Conditional Expression:
1.5< f 3/ f
where f3 represents a focal length of the third lens.
15. The optical imaging system of claim 11 , wherein the optical imaging system satisfies the following Conditional Expression:
3.0<| f 4/ f|
where f4 represents a focal length of the fourth lens.
16. The optical imaging system of claim 11 , wherein an image-side surface of the sixth lens is concave.