Optical imaging system
An optical imaging system according to an embodiment of the present disclosure includes a first lens, a second lens, and a third lens, sequentially arranged from an object side. In the optical imaging system according to the present embodiment, an air gap between the first lens and the second lens is greater than an air gap between the second lens and the third lens. In addition, in the optical imaging system according to the present embodiment, the first lens is formed of a glass material, and a length of the first lens in a first direction, intersecting an optical axis, is different from a length of the first lens in a second direction intersecting the optical axis.
1 . An optical imaging system comprising:
a first lens, a second lens, and a third lens, sequentially arranged from an object side,
wherein the first lens has a positive refractive power,
wherein the second lens has a concave object-side surface and a concave image-side surface,
wherein the third lens has a convex object-side surface,
wherein an Abbe number (V1) of the first lens is greater than 70,
wherein a distance (D12) from an image side surface of the first lens to an object side surface of the second lens is 2 mm or more,
wherein the optical imaging system has a total of three to five lenses with refractive power, and
wherein 0.3<BFL/TTL<0.7 is satisfied, where BFL is a distance from an image side surface of a rearmost lens closest to the image plane to the image plane, and TTL is a distance from an object side surface of the first lens to the image plane.
2 . The optical imaging system of claim 1 , wherein the Abbe number of the first lens is greater than 70 and less than 96.
3 . The optical imaging system of claim 1 , wherein the following conditional expression is satisfied:
2.0 mm< D 12<4.0 mm.
4 . The optical imaging system of claim 1 , wherein a focal length of the first lens is greater than 8.0 mm and less than 16.0 mm.
5 . The optical imaging system of claim 1 , wherein the following conditional expression is satisfied:
1.5 <f/f 1<3.0,
where f is a focal length of the optical imaging system, and f1 is a focal length of the first lens.
6 . The optical imaging system of claim 1 , wherein the following conditional expression is satisfied:
0≤ D 12/ f≤ 0.2,
where f is a focal length of the optical imaging system.
7 . The optical imaging system of claim 1 , wherein the following conditional expression is satisfied:
1.0≤| f 1/ f 2|≤3.0,
where f1 is a focal length of the first lens, and f2 is a focal length of the second lens.
8 . The optical imaging system of claim 1 , wherein the following conditional expression is satisfied:
90< V 1+ V 2,
where V2 is Abbe number of the second lens.
9 . The optical imaging system of claim 1 , wherein the first lens has an effective radius in a first direction intersecting an optical axis, different from an effective radius in a second direction intersecting the optical axis.
10 . The optical imaging system of claim 9 , wherein the following conditional expression is satisfied:
0.5 <ARL 1<1.0,
where ARL1 is a ratio (L1Ry/L1Rx) between the effective radius (L1Ry, a minimum effective radius) in the second direction and the effective radius (L1Rx, a maximum effective radius) in the first direction.
11 . The optical imaging system of claim 1 , wherein the following conditional expression is satisfied:
1.3 ≤D max1 /D max2≤2.0,
where Dmax1 is a maximum effective radius of the first lens, and Dmax2 is a maximum effective radius of the second lens.
12 . The optical imaging system of claim 1 , further comprising an optical path converting member disposed on an object side of the first lens.
13 . The optical imaging system of claim 1 , further comprising a fourth lens or a fourth lens and a fifth lens, sequentially arranged on an image side of the third lens.