Optical imaging system
An optical imaging system is provided. The optical imaging system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens sequentially disposed from an object side to an imaging side. In the optical imaging system, the first lens has positive refractive power and has a concave object-side surface, the fourth lens has negative refractive power, and the fifth lens has a convex image-side surface. Additionally, the optical imaging system satisfies the following conditional expressions: f number<1.90 and 1.90<TTL/f<2.2. In the conditional expressions, TTL is a distance from an object-side surface of the first lens to an image plane, and f is a focal length of the optical imaging system.
1 . An optical imaging system, comprising:
a first lens having positive refractive power, and having a concave object-side surface;
a second lens having refractive power;
a third lens having refractive power;
a fourth lens having negative refractive power;
a fifth lens having a convex image-side surface; and
a sixth lens having refractive power,
wherein the first lens to the sixth lens are sequentially disposed from an object side to an image side, and
wherein
f
number
<
1.9
,
1.9
<
TTL
/
f
<
2.2
,
and 0.90<f4/f6<1.20
where TTL is a distance from an object side of the first lens to an image plane, f is a focal length of the optical imaging system, f4 is a focal length of the fourth lens, and f6 is a focal length of the sixth lens.
2 . The optical imaging system of claim 1 , wherein:
0
<
f
1
/
f
<
2
0
,
where f1 is a focal length of the first lens.
3 . The optical imaging system of claim 1 , wherein:
-
1
0
0
<
f
2
/
f
<
1
0
0
,
where f2 is a focal length of the second lens.
4 . The optical imaging system of claim 1 , wherein:
-
3
0
<
V
1
-
V
2
<
40
,
where V1 is an Abbe number of the first lens and V2 is an Abbe number of the second lens.
5 . The optical imaging system of claim 1 , wherein:
0
.
0
9
<
D
1
2
/
f
<
0
.
1
0
,
where D12 is a distance from an image-side surface of the first lens to an object-side surface of the second lens.
6 . The optical imaging system of claim 1 , wherein:
0
.
0
9
<
D
2
3
/
f
<
0
.
1
0
,
where D23 is a distance from an image-side surface of the second lens to an object-side surface of the third lens.
7 . The optical imaging system of claim 1 , wherein:
0
.
2
0
<
BFL
/
TLx
<
3.
,
where BFL is a distance from an image-side surface of the sixth lens to the image plane, and TLx is a distance from a point closest to an object on an object-side surface of the first lens to the image plane.
8 . An electronic device, comprising the optical imaging system of claim 1 .
9 . An optical imaging system, comprising:
a first lens having a concave object-side surface;
a second lens having refractive power;
a third lens having refractive power;
a fourth lens having a concave object-side surface;
a fifth lens having refractive power; and
a sixth lens having refractive power,
wherein the first lens to the sixth lens are sequentially disposed from an object side to an imaging side, and
wherein
-
1
.
0
<
f
3
/
f
4
<
-
0.8
,
1.9
<
TTL
/
f
<
2
.
2
0
,
and 0.90<f4/f6<1.20
where TTL is a distance from an object-side surface of the first lens to an image plane, f is a focal length of the optical imaging system, f3 is a focal length of the third lens, f4 is a focal length of the fourth lens, and f6 is a focal length of the sixth lens.
10 . The optical imaging system of claim 9 , wherein f number is less than 1.90.
11 . The optical imaging system of claim 9 , wherein:
1.64
<
TTL
/
Im
gHT
<
1.86
,
where ImgHT is a height of the image plane.
12 . The optical imaging system of claim 9 , wherein:
0
.
7
0
<
f3
/
Im
gHT
<
1
.
0
,
where ImgHT is a height of the image plane.
13 . The optical imaging system of claim 9 , wherein:
-
1.1
<
f
3
/
f
6
<
0
.
8
0
,
where f6 is a focal length of the sixth lens.
14 . The optical imaging system of claim 9 , wherein:
-
0
.
8
0
<
(
R
1
1
+
R
1
2
)
/
f
6
<
-
0
.
6
0
,
where R11 is a radius of curvature of an object-side surface of the sixth lens, and R12 is a radius of curvature of an image-side surface of the sixth lens.
15 . The optical imaging system of claim 9 , wherein:
1
4
<
DTn
1
/
DTn
2
<
1
5
,
where DTn1 is a refractive index temperature coefficient according to a temperature change of the first lens, and DTn2 is a refractive index temperature coefficient according to a temperature change of the second lens.
16 . The optical imaging system of claim 9 , wherein:
1
.
5
0
<
(
DTn
1
+
DTn
3
)
/
(
DTn
2
+
DTn
4
)
<
1
.
7
0
,
where DTn1 is a refractive index temperature coefficient according to a temperature change of the first lens, DTn2 is a refractive index temperature coefficient according to a temperature change of the second lens, DTn3 is a refractive index temperature coefficient according to a temperature change of the third lens, and DTn4 is a refractive index temperature coefficient according to a temperature change of the fourth lens.
17 . An electronic device, comprising the optical imaging system of claim 9 .
18 . An optical imaging system, comprising:
a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens;
wherein the first lens has a concave object-side surface,
wherein the fourth lens has a concave object-side surface,
wherein the fifth lens has a concave object-side surface;
wherein the sixth lens has negative refractive power,
wherein the first lens to the sixth lens are sequentially disposed from an object side to an image side, and
wherein
1
.
9
0
<
TTL
/
f
<
2.2
and 0.90<f4/f6<1.20,
where TTL is a distance from an object side of the first lens to an image plane, f is a focal length of the optical imaging system, f4 is a focal length of the fourth lens, and f6 is a focal length of the sixth lens.
19 . An electronic device, comprising the optical imaging system of claim 18 .