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 of the optical imaging system from an object side of the optical imaging system toward an imaging plane of the optical imaging system, wherein the first to seventh lenses are spaced apart from each other along the optical axis, and the optical imaging system satisfies 0.4<L1TR/L7TR<1.9, where L1TR is an overall outer diameter of the first lens, L7TR is an overall outer diameter of the seventh lens, and L1TR and L7TR are expressed in a same unit of measurement.
1. An optical imaging system comprising:
a first lens having a positive refractive power, a convex object-side surface in a paraxial region thereof, and a concave image-side surface in a paraxial region thereof;
a second lens having a negative refractive power, a convex object-side surface in a paraxial region thereof, and a concave image-side surface in a paraxial region thereof;
a third lens having a negative refractive power, a convex object-side surface in a paraxial region thereof, and a concave image-side surface in a paraxial region thereof;
a fourth lens having a positive refractive power and a convex image-side surface in a paraxial region thereof;
a fifth lens having a negative refractive power;
a sixth lens having a refractive power and a concave image-side surface in a paraxial region thereof;
a seventh lens having a negative refractive power,
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,
the optical imaging system satisfies SD12<SD34, where SD12 is a distance along the optical axis from the image-side surface of the first lens to the object-side surface of the second lens, SD34 is a distance along the optical axis from the 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, and
the optical imaging system further comprises a spacer disposed between the sixth and seventh lenses and satisfies 0.5<S6d/f<1.4, where S6d is an inner diameter of the spacer, f is an overall focal length of the optical imaging system, and S6d and f are expressed in a same unit of measurement.
2. The optical imaging system of claim 1 , wherein the optical imaging system satisfies 0.01<R1/R4<1.3, where R1 is a radius of curvature on the optical axis of the object-side surface of the first lens, R4 is a radius of curvature on the optical axis of the image-side surface of the second lens, and R1 and R4 are expressed in a same unit of measurement.
3. The optical imaging system of claim 1 , wherein the optical imaging system satisfies 0.05<R1/R6<0.9, where R1 is a radius of curvature on the optical axis of the object-side surface of the first lens, R6 is a radius of curvature on the optical axis of the image-side surface of the third lens, and R1 and R6 are expressed in a same unit of measurement.
4. The optical imaging system of claim 1 , wherein the sixth lens has a convex object-side surface in a paraxial region thereof, and
the optical imaging system satisfies 0.2<R1/R11<1.2, where R1 is a radius of curvature on the optical axis of the object-side surface of the first lens, R11 is a radius of curvature on the optical axis of the object-side surface of the sixth lens, and R1 and R11 are expressed in a same unit of measurement.
5. The optical imaging system of claim 1 , wherein the sixth lens has a convex object-side surface in a paraxial region thereof,
the seventh lens has a concave image-side surface in a paraxial region thereof, and
the optical imaging system satisfies 0.6<(R11+R14)/(2*R1)<3.0, where R1 is a radius of curvature on the optical axis of the object-side surface of the first lens, R11 is a radius of curvature on the optical axis of the object-side surface of the sixth lens, R14 is a radius of curvature on the optical axis of an image-side surface of the seventh lens, and R1, R11, and R14 are expressed in a same unit of measurement.
6. 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, and f1, f2, f3, f4, f5, f6, f7, and f 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)*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 the 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.
8. The optical imaging system of claim 1 , wherein the sixth lens has a convex object-side surface in a paraxial region thereof,
the seventh lens has a concave image-side surface in a paraxial region thereof, and
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.
9. The optical imaging system of claim 1 , wherein the optical imaging system satisfies SD56<SD67, where SD56 is a distance along the optical axis from an image-side surface of the fifth lens to an object-side surface of the sixth lens, SD67 is a distance along the optical axis from the image-side surface of the sixth lens to an object-side surface of the seventh lens, and SD56 and SD67 are expressed in a same unit of measurement.
10. 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 the object-side surface of the first lens to the imaging plane, and ΣTD and TTL are expressed in a same unit of measurement.
11. 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 the object-side surface of the first lens to the imaging plane, IMG HT is an image height on the imaging plane and is equal to one half of a diagonal length of the imaging plane, and TTL and IMG HT are expressed in a same unit of measurement.
12. The optical imaging system of claim 1 , wherein the fourth lens has a convex object-side surface in a paraxial region thereof, the sixth lens has a convex object-side surface in a paraxial region thereof, and the seventh lens has a concave image-side surface in a paraxial region thereof.
13. An optical imaging system comprising:
a first lens having a positive refractive power, a convex object-side surface in a paraxial region thereof, and a concave image-side surface in a paraxial region thereof;
a second lens having a negative refractive power, a convex object-side surface in a paraxial region thereof, and a concave image-side surface in a paraxial region thereof;
a third lens having a negative refractive power, a convex object-side surface in a paraxial region thereof, and a concave image-side surface in a paraxial region thereof;
a fourth lens having a positive refractive power;
a fifth lens having a negative refractive power;
a sixth lens having a refractive power; and
a seventh lens having a negative refractive power,
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,
the fourth lens has a convex object-side surface in a paraxial region thereof, the sixth lens has a convex object-side surface in a paraxial region thereof, and the seventh lens has a concave image-side surface in a paraxial region thereof,
the fourth lens has a convex image-side surface in a paraxial region thereof, and the sixth lens has a concave image-side surface in a paraxial region thereof, and
the optical imaging system further comprises a spacer disposed between the sixth and seventh lenses and satisfies 0.5<S6d/f<1.4, where S6d is an inner diameter of the spacer, f is an overall focal length of the optical imaging system, and S6d and f are expressed in a same unit of measurement.