Optical imaging system
An optical imaging system includes a first lens having a positive refractive power, a second lens having a negative refractive power, a third lens having a negative refractive power, a fourth lens, a fifth lens, and a sixth lens having a positive refractive power and having a convex image-side shape, sequentially arranged in a direction from an object side of the optical imaging system to an imaging plane of the optical imaging system.
1. An optical imaging system, comprising:
a first lens comprising a positive refractive power;
a second lens comprising a negative refractive power;
a third lens comprising a negative refractive power;
a fourth lens comprising a convex image-side surface;
a fifth lens; and
a sixth lens comprising a positive refractive power and further comprising a convex object-side shape along an optical axis of the optical imaging system,
wherein the optical imaging system satisfies the following conditional expression,
0.7< TL/f< 1.0
where TL represents a distance from an object-side surface of the first lens to an imaging plane, and f represents a total focal length of the optical imaging system.
2. The optical imaging system of claim 1 , wherein the second lens comprises a concave image-side surface along the optical axis.
3. The optical imaging system of claim 1 , wherein the third lens comprises a concave image-side surface along the optical axis.
4. The optical imaging system of claim 1 , wherein the fourth lens comprises a convex object-side surface along the optical axis.
5. The optical imaging system of claim 1 , wherein the fifth lens comprises a concave image-side surface along the optical axis.
6. The optical imaging system of claim 1 , wherein the first to sixth lenses are disposed comprising an interval between each respective lens.
7. The optical imaging system of claim 1 , wherein the fifth lens comprises a negative refractive power.
8. The optical imaging system of claim 1 , wherein the optical imaging system satisfies the following conditional expression,
0.15< R 1/ f< 0.32
where R1 represents a radius of curvature of an object-side surface of the first lens.
9. The optical imaging system of claim 1 , wherein the optical imaging system satisfies the following conditional expression,
−3.5< f/f 2<−0.5
where f2 represents a focal length of the second lens.
10. The optical imaging system of claim 1 , wherein the optical imaging system satisfies the following conditional expression,
0.1< D 45/ TL< 0.7
where D45 represents a distance from an image-side surface of the fourth lens to an object-side surface of the fifth lens.
11. The optical imaging system of claim 1 , wherein the optical imaging system satisfies the following conditional expression,
1.60< Nd 6<1.75
where Nd6 represents a refractive index of the sixth lens.
12. The optical imaging system of claim 1 , wherein the optical imaging system satisfies the following conditional expression,
0.3<tan θ<0.5
where θ represents a half angle of view of the optical imaging system.
13. The optical imaging system of claim 1 , wherein the optical imaging system satisfies the following conditional expression,
2.0< f/EPD< 2.7
where EPD represents a diameter of an entrance aperture.
14. An optical imaging system, comprising:
a first lens comprising a convex image-side surface, a second lens, a third lens comprising a concave object-side surface, a fourth lens, a fifth lens, and a sixth lens comprising positive refractive power and a convex object-side surface sequentially arranged from an object side to an image side,
wherein the optical imaging system satisfies the following conditional expression,
0.7< TL/f< 1.0
where TL represents a distance from an object-side surface of the first lens to an imaging plane, and f represents a total focal length of the optical imaging system.
15. The optical imaging system of claim 14 , wherein the sixth lens comprises a shape in which an image-side surface is convex along an optical axis of the optical imaging system and an inflection point is formed on the image-side surface.