Optical imaging system and camera module including the same
An optical imaging system includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens sequentially disposed along an optical axis from an object-side surface of the first lens toward an imaging plane of an image sensor, wherein 3.5≤TTL/IMG HT, f1+f2|<2.0 mm, and 0.7≤L1S1es/L1S1el<1.0 are satisfied, where TTL is a distance along the optical axis from the object-side surface of the first lens to the imaging plane of the image sensor, IMG HT is one-half of a diagonal length of the imaging plane of the image sensor, f1 is a focal length of the first lens, f2 is a focal length of the second lens, L1S1el is a maximum effective radius of the object-side surface of the first lens, and L1S1es is a minimum effective radius of the object-side surface of the first lens.
1 . An optical imaging system comprising:
a first lens, a second lens, a third lens, a fourth lens, and a fifth lens sequentially disposed in ascending numerical order along an optical axis of the optical imaging system from an object-side surface of the first lens toward an imaging plane of the optical imaging system,
wherein the first lens has a positive refractive power and a convex object-side surface in a paraxial region thereof,
the second lens has a negative refractive power,
the third lens has 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,
the fourth lens has a positive refractive power and a concave object-side surface in a paraxial region thereof,
the fifth lens has a negative refractive power,
the optical imaging system has a total of five lenses,
3.5≤TTL/IMG HT and 0≤D12/f≤0.07 are satisfied, 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 one half of a diagonal length of the imaging plane, D12 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, and f is a total focal length of the optical imaging system, and
|f1+f2|<2.0 mm is satisfied, where f1 is a focal length of the first lens, and f2 is a focal length of the second lens.
2 . The optical imaging system of claim 1 , wherein 0.8≤TTL/f≤1.25 is satisfied.
3 . The optical imaging system of claim 1 , further comprising a reflective member disposed between an object side of the optical imaging system and the object-side surface of the first lens,
wherein the reflective member comprises a reflective surface configured to receive incident light from an object and reflect the incident light toward the object-side surface of the first lens.
4 . The optical imaging system of claim 3 , wherein the first lens has two axes intersecting the optical axis and perpendicular to each other, and a length of one of the two axes is greater than a length of another one of the two axes, and
0<L1S1el/PTTL<0.14 is satisfied, where L1S1el is a maximum effective radius of the object-side surface of the first lens, and PTTL is a distance along the optical axis from the reflective surface to the imaging plane.
5 . The optical imaging system of claim 3 , wherein the first lens has two axes intersecting the optical axis and perpendicular to each other, and a length of one of the two axes is greater than a length of another one of the two axes,
the first lens comprises:
an optical portion exhibiting a lens characteristic of the first lens; and
a flange portion not exhibiting a lens characteristic of the first lens and extending from an edge of at least a portion of the optical portion in a direction away from the optical axis, and
0<AL1/(PTTL) 2 <0.05 is satisfied, where AL1 is an area of the optical portion of the object-side surface of the first lens when the first lens is viewed in a direction of the optical axis, and PTTL is a distance along the optical axis from the reflective surface to the imaging plane.
6 . The optical imaging system of claim 3 , wherein 0<L2S1el/PTTL<0.14 is satisfied, where L2S1el is a maximum effective radius of the object-side surface of the second lens, and PTTL is a distance along the optical axis from the reflective surface to the imaging plane.
7 . The optical imaging system of claim 1 , wherein the first lens has two axes intersecting the optical axis and perpendicular to each other, and a length of one of the two axes is greater than a length of another one of the two axes, and
0.7≤L1S1es/L1S1el<1.0 is satisfied, where L1S1el is a maximum effective radius of the object-side surface of the first lens, and L1S1es is a minimum effective radius of the object-side surface of the first lens.
8 . The optical imaging system of claim 1 , wherein the first lens has two axes intersecting the optical axis and perpendicular to each other, and a length of one of the two axes is greater than a length of another one of the two axes,
the first lens comprises:
an optical portion exhibiting a lens characteristic of the first lens; and
a flange portion not exhibiting a lens characteristic of the first lens and extending from an edge of at least a portion of the optical portion in a direction away from the optical axis,
the optical portion comprises:
a first edge and a second edge disposed on opposite sides of the optical axis in a first direction; and
a third edge and a fourth edge disposed on opposite sides of the optical axis in a second direction perpendicular to the first direction,
the third edge connects a first end of the first edge to a first end of the second edge,
the fourth edge connects a second end of the first edge to a second end of the second edge, and
a shortest distance between the first edge and the second edge is greater than a shortest distance between the third edge and the fourth edge.
9 . The optical imaging system of claim 8 , wherein 0°<α<92° is satisfied, where α is an angle between a first virtual line connecting a connection point between the second end of the first edge and the fourth edge to the optical axis, and a second virtual line connecting a connection point between the second end of the second edge and the fourth edge to the optical axis.
10 . The optical imaging system of claim 8 , wherein 1.5<α/FOV <3.0 is satisfied, where α is an angle between a first virtual line connecting a connection point between the second end of the first edge and the fourth edge to the optical axis, and a second virtual line connecting a connection point between the second end of the second edge and the fourth edge to the optical axis, and FOV is an angle of view of the optical imaging system.
11 . The optical imaging system of claim 1 , wherein 0.8<BFL/(2*IMG HT)<2.5 is satisfied, where BFL is a distance along the optical axis from an image-side surface of the fifth lens to the imaging plane.
12 . The optical imaging system of claim 1 , wherein 0.2≤R1/f≤0.6 is satisfied, where R 1 is a radius of curvature of the object-side surface of the first lens.
13 . The optical imaging system of claim 1 , further comprising a spacer disposed between the first lens and the second lens and comprising an opening through which light passes from the first lens to the second lens,
wherein 0.7≤s1es/s1el<1.0 is satisfied, where s1el is a maximum radius of the opening when the opening is viewed in a direction of the optical axis, and s1es is a minimum radius of the opening when the opening is viewed in the direction of the optical axis.
14 . The optical imaging system of claim 1 , wherein the second lens has a concave image-side surface in a paraxial region thereof.
15 . The optical imaging system of claim 1 , wherein the fourth lens has a convex image-side surface in a paraxial region thereof.
16 . The optical imaging system of claim 1 , wherein the fifth lens has a concave image-side surface in a paraxial region thereof.
17 . The optical imaging system of claim 1 , wherein at least one lens among the first to fifth lenses has an aspherical surface.