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 numerical order along an optical axis from an object side toward an imaging plane, wherein the seventh lens includes an optical portion configured to refract light, and a rib surrounding the optical portion; the rib includes a surface-treated area disposed in a first portion of an object-side surface of the rib and a first portion of an image-side surface of the rib, a first non-treated area disposed in a second portion of the object-side surface of the rib, and a second non-treated area disposed in a second portion of the image-side surface of the rib; and the first non-treated area and the second non-treated area overlap each other when viewed in a direction of the optical axis.
1. An optical imaging system comprising:
a first lens having a positive refractive power, a convex object-side surface, and a concave image-side surface;
a second lens having a negative refractive power;
a third lens having a negative refractive power and a convex object-side surface in a paraxial region thereof;
a fourth lens having a positive refractive power;
a fifth lens having a negative refractive power and a convex object-side surface in a paraxial region thereof;
a sixth lens having a refractive power; and
a seventh lens having a refractive power and a concave image-side surface,
wherein the first to seventh lenses are sequentially disposed in ascending numerical order along an optical axis of the optical imaging system from an object side of the optical imaging system toward an imaging plane of the optical imaging system, and
wherein the optical imaging system satisfies 0.2<TD1/D67<0.8, where TD1 is a thickness along the optical axis of the first lens, D67 is a distance along the optical axis from the object-side surface of the sixth lens to the image-side surface of the seventh lens, and TD1 and D67 are expressed in a same unit of measurement.
2. The optical imaging system of claim 1 , wherein the first lens has a convex object-side surface and a concave image-side surface, and the second lens has a convex object-side surface and a concave image-side surface.
3. The optical imaging system of claim 2 , wherein the optical imaging system satisfies 0.01<R1/R4<1.3, where R1 is a radius of curvature of the object-side surface of the first lens, R4 is a radius of curvature of the image-side surface of the second lens, and R1 and R4 are expressed in a same unit of measurement.
4. The optical imaging system of claim 2 , wherein the third lens has a concave image-side surface, and
the optical imaging system satisfies 0.05<R1/R6<0.9, where R1 is a radius of curvature of the object-side surface of the first lens, R6 is a radius of curvature of the image-side surface of the third lens, and R1 and R6 are expressed in a same unit of measurement.
5. The optical imaging system of claim 4 , wherein the optical imaging system further satisfies 0.1<R1/R5<0.7, where R5 is a radius of curvature of the object-side surface of the third lens, and R1 and R5 are expressed in a same unit of measurement.
6. The optical imaging system of claim 1 , wherein the first lens has a convex object-side surface, the sixth lens has a convex object-side surface, and the seventh lens has a concave image-side surface, and
the optical imaging system satisfies 0.6< (R11+R14)/(2*R1)<3.0, where R1 is a radius of curvature of the object-side surface of the first lens, R11 is a radius of curvature of the object-side surface of the sixth lens, R14 is a radius of curvature of the image-side surface of the seventh lens, and R1, R11, and R14 are expressed in a same unit of measurement.
7. The optical imaging system of claim 1 , wherein the optical imaging system satisfies 0.1< (1/f1+1/f2+1/f3+1/f4+1/f5+1/f6+1/f7)*f<0.8, where f1 is a focal length of the first lens, f2 is a focal length of the second lens, f3 is a focal length of the third lens, f4 is a focal length of the fourth lens, f5 is a focal length of the fifth lens, f6 is a focal length of the sixth lens, f7 is a focal length of the seventh lens, f is an overall focal length of the optical imaging system, and f1, f2, f3, f4, f5, f6, f7, and f are expressed in a same unit of measurement.
8. The optical imaging system of claim 1 , wherein the optical imaging system satisfies 0.1< (1/f1+1/f2+1/f3+1/f4+1/f5+1/f6+1/f7)*TTL<1.0, where f1 is a focal length of the first lens, f2 is a focal length of the second lens, f3 is a focal length of the third lens, f4 is a focal length of the fourth lens, f5 is a focal length of the fifth lens, f6 is a focal length of the sixth lens, f7 is a focal length of the seventh lens, TTL is a distance along the optical axis from an object-side surface of the first lens to the imaging plane, and f1, f2, f3, f4, f5, f6, f7, and TTL are expressed in a same unit of measurement.
9. The optical imaging system of claim 1 , wherein the optical imaging system satisfies SD12<SD34, where SD12 is a distance along the optical axis from an image-side surface of the first lens to an object-side surface of the second lens, SD34 is a distance along the optical axis from an image-side surface of the third lens to an object-side surface of the fourth lens, and SD12 and SD34 are expressed in a same unit of measurement.
10. The optical imaging system of claim 1 , wherein the optical imaging system satisfies 0.6<TTL/(2*IMG HT)<0.9, where TTL is a distance along the optical axis from an object-side surface of the first lens to the imaging plane, IMG HT is one-half of a diagonal length of the imaging plane, and TTL and IMG HT are expressed in a same unit of measurement.
11. The optical imaging system of claim 1 , wherein the optical imaging system satisfies 0.4<ΣTD/TTL<0.7, where ΣTD is a sum of thicknesses along the optical axis of the first to seventh lenses, TTL is a distance along the optical axis from an object-side surface of the first lens to the imaging plane, and ΣTD and TTL are expressed in a same unit of measurement.