Optical system for camera
Disclosed herein is an optical system for a camera. The optical system for a camera includes: a first lens having positive refractive power and a meniscus shape concave toward an image; a second lens having negative refractive power and a shape concave toward the image; a third lens having the positive refractive power and a shape convex toward an object; a fourth lens having the positive refractive power and a shape convex toward the image; and a fifth lens having the negative refractive power, a shape convex toward the object and concave to the image, and one or more inflection point provided on an image surface.
1. An optical system, comprising
a first lens having positive refractive power and being convex toward an object side;
a second lens having negative refractive power and being concave toward an image side;
a third lens having positive refractive power and being biconvex;
a fourth lens having positive refractive power and being convex toward the image side;
a fifth lens having negative refractive power and being convex in the center toward the object side and concave in the center toward the image side, the fifth lens having at least one inflection point on an image-side surface; and
an aperture stop disposed in front of the first lens to adjust a light amount,
wherein the optical system satisfies the following conditional expression:
1.744≦ r 1≦1.938
1.658≦ r 4≦3.145
where r1 is a radius of curvature of an object-side surface of the first lens and r4 is a radius of curvature of an image-side surface of the second lens, and
wherein the first lens, the second lens, the third lens, the fourth lens and the fifth lens are arranged in order from the object side to the image side.
2. The optical system of claim 1 , wherein:
the fourth lens is concave toward the object side and has a meniscus shape, and
the fifth lens comprises:
an object-side surface being convex in the center and concave at the periphery; and
an image-side surface being concave in the center and convex at the periphery.
3. The optical system of claim 1 , wherein the optical system satisfies the following conditional expression:
| R 52/ R 42|> TTL/f
where R52 is a radius of curvature of an image-side surface of the fifth lens, R42 is a radius of curvature of an image-side surface of the fourth lens, TTL is a distance on an optical axis from an object-side surface of the first lens to an image plane, and f is a total focal length of the optical system.
4. The optical system of claim 1 , wherein the optical system satisfies the following conditional expression:
| R 31 +R 32+ R 41+ R 42|> TTL
where R31 is a radius of curvature of an object-side surface of the third lens, R32 is a radius of curvature of an image-side surface of the third lens, R41 is a radius of curvature of an object-side surface of the fourth lens, R42 is a radius of curvature of an image-side surface of the fourth lens, and TTL is a distance on an optical axis from an object-side surface of the first lens to an image sensor.
5. The optical system of claim 1 , wherein the optical system satisfies the following conditional expression:
-
0.670
<
r
5
+
r
6
r
5
-
r
6
<
-
0.027
where r5 is a radius of curvature of an object-side surface of the third lens, and r6 is a radius of curvature of an image-side surface of the third lens.
6. The optical system of claim 1 , wherein the optical system satisfies the following conditional expression:
1.983
<
r
2
f
<
7.874
where r2 is a radius of curvature of an image-side surface of the first lens, and f is a total focal length of the optical system.
7. The optical system of claim 1 , wherein the optical system satisfies the following conditional expression:
8.133≦| r 1|≦32.755
where r2 is a radius of curvature of an image-side surface of the first lens.
8. The optical system of claim 1 , wherein the optical system satisfies the following conditional expression:
2.466
<
r
3
r
4
<
6.273
-
0.946
<
r
5
r
6
<
-
0.198
where r3 is a radius of curvature of an object-side surface of the second lens, r4 is a radius of curvature of an image-side surface of the second lens, r5 is a radius of curvature of an object-side surface of the third lens, and r6 is a radius of curvature of an image-side surface of the third lens.
9. The optical system of claim 1 , wherein the optical system satisfies the following conditional expression:
0.03 ≦d 12≦0.08
0.08 ≦d 45≦0.23
where d12 is a distance from an image-side surface of the first lens to an object-side surface of the second lens, and d45 is a distance from an image-side surface of the fourth lens to an object-side surface of the fifth lens.
10. The optical system of claim 1 , wherein the optical system satisfies the following conditional expression:
0.007
<
d
12
f
<
0.021
0.019
<
d
45
f
<
0.079
0.068
<
d
34
f
3
<
0.144
where d12 is a distance from an image-side surface of the first lens to an object-side surface of the second lens, d45 is a distance from an image-side surface of the fourth lens to an object-side surface of the fifth lens, f is a total focal length of the optical system, d34 is a distance from an image-side surface of the third lens to an object-side surface of the fourth lens, and f3 is a focal length of the third lens.
11. The optical system of claim 1 , wherein the optical system satisfies the following conditional expression:
−1.621 ≦r 8≦−0.877
where r8 is a radius of curvature of an image-side surface of the fourth lens.
12. The optical system of claim 1 , wherein the optical system satisfies the following conditional expression:
1.037
<
r
3
f
<
4.743
0.420
<
r
4
f
<
0.757
-
0.412
<
r
8
f
<
-
0.215
where r3 is a radius of curvature of an object-side surface of the second lens, r4 is a radius of curvature of an image-side surface of the second lens, r8 is a radius of curvature of an image-side surface of the fourth lens, and f is a total focal length of the optical system.
13. The optical system of claim 1 , wherein the optical system satisfies the following conditional expression:
0.725
<
r
3
+
r
4
r
3
-
r
4
<
2.365
where r3 is a radius of curvature of an object-side surface of the second lens, and r4 is a radius of curvature of an image-side surface of the second lens.
14. The optical system of claim 1 , wherein the optical system satisfies the following conditional expression:
-
1.743
<
f
4
f
5
<
-
1.080
where f4 is a focal length of the fourth lens, and f5 is a focal length of the fifth lens.
15. The optical system of claim 2 , wherein the first, second, third, fourth and fifth lenses comprise an asperical surface.
16. The optical system of claim 2 , wherein the optical system satisfies the following conditional equation:
f 3 /f< 2.0
where f3 indicates a focal length of the third lens, and f indicates a total focal length of the optical system.
17. The optical system of claim 2 , wherein abbe numbers of the first, third, fourth and fifth lenses are about 56.
18. The optical system of claim 2 , wherein the optical system satisfies the following conditional expression:
d 11> d 31
where d11 is a thickness of the first lens, and d31 is a thickness of the third lens.
19. The optical system of claim 11 , wherein the optical system satisfies the following conditional expression:
4.089≦| r 3|≦19.728
where r3 is a radius of curvature of an object-side surface of the second lens.
20. The optical system of claim 15 , wherein the first, second, third, fourth and fifth lenses are made of plastic.
21. The optical system of claim 17 , wherein an abbe number of the second lens is about 23.7.
22. The optical system of claim 20 , further comprising an optical filter provided between the fifth lens and the image side to block excessive infrared rays.
23. An optical system, comprising
a first lens having positive refractive power and comprising a convex surface on an object side;
a second lens having negative refractive power and comprising a concave surface on an image side;
a third lens having positive refractive power and a biconvex shape;
a fourth lens having positive refractive power and a meniscus shape being concave toward the object side and convex toward the image side; and
a fifth lens having negative refractive power and comprising:
an object-side surface being convex in the center and concave at the periphery; and
an image-side surface being concave in the center and convex at the periphery, wherein the optical system satisfies the following conditional expression:
1.744 ≦r 1≦1.938
1.658≦ r 4≦3.145
where r1 is a radius of curvature of an object-side surface of the first lens and r4 is a radius of curvature of an image-side surface of the second lens,
wherein the first lens, the second lens, the third lens, the fourth lens and the fifth lenses are arranged in order from the object side to the image side, and
wherein the convex surface of the first lens, the concave surface of the second lens, the biconvex shape of the third lens, and the meniscus shape of the fourth lens are arranged on an optical axis.
24. The optical system of claim 23 , wherein the optical system satisfies the following conditional equation:
f 3 /f< 2.0
where f3 indicates a focal length of the third lens, and f indicates a total focal length of the entire optical system.
25. The optical system of claim 24 , wherein the optical system satisfies the following conditional expression:
d 11> d 31
where d11 is a thickness of the first lens, and d31 is a thickness of the third lens.
26. The optical system of claim 24 , wherein the optical system satisfies the following conditional expression:
0.03≦ d 12≦0.08
0.08≦ d 45≦0.23
where d12 is a distance from an image-side surface of the first lens to an object-side surface of the second lens, and d45 is a distance from an image-side surface of the fourth lens to an object-side surface of the fifth lens.
27. The optical system of claim 26 , wherein the optical system satisfies the following conditional expression:
−1.621 ≦r 8≦−0.877
where r8 is a radius of curvature of an image-side surface of the fourth lens.
28. The optical system of claim 26 , wherein the optical system satisfies the following conditional expression:
0.007
<
d
12
f
<
0.021
0.019
<
d
45
f
<
0.079
0.068
<
d
34
f
3
<
0.144
where d12 is a distance from an image-side surface of the first lens to an object-side surface of the second lens, d45 is a distance from an image-side surface of the fourth lens to an object-side surface of the fifth lens, f is a total focal length of the optical system, d34 is a distance from an image-side surface of the third lens to an object-side surface of the fourth lens, and f3 is a focal length of the third lens.
29. The optical system of claim 26 , wherein the optical system satisfies the following conditional expression:
-
1.743
<
f
4
f
5
<
-
1.080
where f4 is a focal length of the fourth lens, and f5 is a focal length of the fifth lens.
30. The optical system of claim 27 , wherein the optical system satisfies the following conditional expression:
8.133≦| r 2|≦32.755
4.089≦| r 3|≦19.728
where r2 is a radius of curvature of an image-side surface of the first lens, and r3 is a radius of curvature of an object-side surface of the second lens.