Optical imaging system
An optical imaging system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens sequentially disposed in ascending numerical order along an optical axis from an object side of the optical imaging system toward an imaging plane of the optical imaging system. Four or more lenses among the first to seventh lenses have a refractive index greater than 1.6.
1 . An optical imaging system comprising:
a first lens having a positive refractive power;
a second lens having a refractive power;
a third lens having a refractive power;
a fourth lens having a convex object-side surface along an optical axis of the optical imaging system;
a fifth lens having a positive refractive power;
a sixth lens having a convex object-side surface along the optical axis and an image-side surface having an inflection point formed thereon; and
a seventh lens having a convex object-side surface along the optical axis and an image-side surface having an inflection point formed thereon,
wherein the first to seventh lenses are sequentially disposed in ascending numerical order along the optical axis from an object side of the optical imaging system toward an imaging plane of the optical imaging system,
the optical imaging system has a total number of seven lenses having a refractive power,
the second lens has a refractive index greater than or equal to 1.65,
an F number of the optical imaging system is less than or equal to 2.09,
a thickness of the sixth lens along the optical axis is greater than a thickness of the third lens along the optical axis,
an absolute value of a radius of curvature of the object-side surface of the fourth lens is greater than an absolute value of a radius of curvature of an object-side surface of the second lens,
a thickness of the fourth lens is greater than a distance from an image-side surface of the fourth lens to an object-side surface of the fifth lens, and
an absolute value of a radius of curvature of an image-side surface of the second lens is greater than an absolute value of a radius of curvature of an object-side surface of the first lens.
2 . The optical imaging system of claim 1 , wherein the first lens has a convex object-side surface along the optical axis.
3 . The optical imaging system of claim 1 , wherein the first lens has a concave image-side surface along the optical axis.
4 . The optical imaging system of claim 1 , wherein the second lens has a convex object-side surface along the optical axis.
5 . The optical imaging system of claim 1 , wherein the second lens has a concave image-side surface along the optical axis.
6 . The optical imaging system of claim 1 , wherein the image-side surface of the sixth lens is concave along the optical axis.
7 . The optical imaging system of claim 1 , wherein the image-side surface of the seventh lens is concave along the optical axis.
8 . An optical imaging system comprising:
a first lens having a positive refractive power;
a second lens having a refractive power;
a third lens having a refractive power;
a fourth lens having a refractive power;
a fifth lens having a positive refractive power;
a sixth lens having a negative refractive power, a convex object-side surface along an optical axis of the optical imaging system, and an image-side surface having an inflection point formed thereon; and
a seventh lens having a convex object-side surface along the optical axis and an image-side surface having an inflection point formed thereon,
wherein the first to seventh lenses are sequentially disposed in ascending numerical order along the optical axis from an object side of the optical imaging system toward an imaging plane of the optical imaging system,
the optical imaging system has a total number of seven lenses having a refractive power,
the second lens has a refractive index greater than or equal to 1.65,
an F number of the optical imaging system is less than or equal to 2.09,
a thickness of the sixth lens along the optical axis is greater than a thickness of the third lens along the optical axis,
an absolute value of a radius of curvature of an object-side surface of the fourth lens is greater than an absolute value of a radius of curvature of an object-side surface of the second lens,
a thickness of the fourth lens is greater than a distance from an image-side surface of the fourth lens to an object-side surface of the fifth lens, and
an absolute value of a radius of curvature of an image-side surface of the second lens is greater than an absolute value of a radius of curvature of an object-side surface of the first lens.
9 . The optical imaging system of claim 8 , wherein the first lens has a convex object-side surface along the optical axis.
10 . The optical imaging system of claim 8 , wherein the image-side surface of the first lens is concave along the optical axis.
11 . The optical imaging system of claim 8 , wherein the second lens has a convex object-side surface along the optical axis.
12 . The optical imaging system of claim 8 , wherein the second lens has a concave image-side surface along the optical axis.
13 . The optical imaging system of claim 8 , wherein the third lens has a convex object-side surface along the optical axis.
14 . The optical imaging system of claim 8 , wherein the sixth lens has a refractive index greater than or equal to 1.65.