Optical imaging system and portable electronic device including the same
An optical imaging system includes a plurality of lenses disposed along an optical axis, and a reflection member disposed to be closer to an object than all of the plurality of lenses and having a reflection surface configured to change a path of light. The plurality of lenses are spaced apart from each other by preset distances along the optical axis, and the condition 0.8<TTL/ft<1.1 is satisfied, where TTL is a distance from an object-side surface of a lens closest to the object among the plurality of lenses to an imaging plane of an image sensor, and ft is an overall focal length of an optical system including the plurality of lenses.
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 convex image-side surface in a paraxial region thereof;
a second lens having a negative refractive power;
a third lens having a positive refractive power;
a fourth lens having a positive refractive power; and
a fifth lens having a negative refractive power, a concave object-side surface in a paraxial region thereof, and a convex image-side surface in a paraxial region thereof,
wherein the first to fifth lenses are sequentially arranged in ascending numerical order along an optical axis of the optical imaging system from an object side of the optical imaging system to an imaging plane of the optical imaging system,
the optical imaging system has a total of five lenses, and
0.8<TTL/ft<1.1 is satisfied, where TTL is a distance along the optical axis from the object-side surface of the first lens to the imaging plane, and ft is an overall focal length of the optical imaging system.
2 . The optical imaging system of claim 1 , wherein 1.5<ft/ft1<3.5 is satisfied, where ft1 is a focal length of the first lens.
3 . The optical imaging system of claim 1 , wherein a field of view (FOVt) of the optical imaging system is less than or equal to 40°.
4 . The optical imaging system of claim 1 , wherein the second lens has a concave image-side surface in a paraxial region thereof.
5 . The optical imaging system of claim 1 , wherein the third lens has a convex object-side surface in a paraxial region thereof.
6 . The optical imaging system of claim 1 , wherein the fourth lens has a concave object-side surface in a paraxial region thereof.
7 . The optical imaging system of claim 6 , wherein the fourth lens has a convex image-side surface in a paraxial region thereof.
8 . The optical imaging system of claim 1 , wherein a thickness of the first lens along the optical axis is greatest among the first to fifth lenses.
9 . The optical imaging system of claim 8 , wherein a thickness of the fourth lens along the optical axis is second-greatest among the first to fifth lenses.
10 . The optical imaging system of claim 1 , wherein the first to fifth lenses are each made of a plastic material.
11 . The optical imaging system of claim 10 , wherein the first lens and the second lens are made of different plastic materials having different Abbe numbers.
12 . The optical imaging system of claim 11 , wherein the fourth lens and the fifth lens are made of different plastic materials having different Abbe numbers.
13 . The optical imaging system of claim 1 , wherein an object-side surface and an image-side surface of each of the first to fifth lenses are aspheric.
14 . The optical imaging system of claim 1 , wherein the first lens, among the first to fifth lenses, has a smallest absolute value of focal length.
15 . The optical imaging system of claim 14 , wherein the second lens, among the first to fifth lenses, has a second-smallest absolute value of focal length.
16 . The optical imaging system of claim 15 , wherein the third lens, among the first to fifth lenses, has a largest absolute value of focal length.
17 . The optical imaging system of claim 1 , wherein a distance between the third lens and the fourth lens along the optical axis is greater than a distance between the first lens and the second lens along the optical axis, a distance between the second lens and the third lens along the optical axis, and a distance between the fourth lens and the fifth lens along the optical axis.