Image pickup lens
An imaging lens for a solid-state imaging sensor includes, in order from an object side to an image side of the imaging lens, a first through sixth lens. The first lens has positive refractive power. The second lens has positive refractive power. The third lens has negative refractive power. The fourth lens has positive or negative refractive power and aspheric surfaces facing the object side and the image side. The fifth lens has positive refractive power. The sixth lens has negative refractive power and aspheric surfaces facing the object side and the image side.
1. An imaging lens for a solid-state imaging sensor, comprising, in order from an object side to an image side of the imaging lens:
a first lens having positive refractive power;
a second lens having positive refractive power;
a third lens having negative refractive power;
a fourth lens having positive or negative refractive power and aspheric surfaces facing the object side and the image side;
a fifth lens having positive refractive power; and
a sixth lens having negative refractive power and aspheric surfaces facing the object side and the image side;
wherein conditional expressions (1), and (9) to (12) below are satisfied:
0.84<| r 1/ f| (1)
20<ν d 4<30 (9)
50<ν d 5<80 (10)
50<ν d 6<80 (11)
0.80< ih/f< 1.1 (12)
where
f: overall focal length of the imaging lens,
r1: curvature radius of an object-side surface of the first lens,
νd4: Abbe number of the fourth lens at d-ray,
νd5: Abbe number of the fifth lens at d-ray,
νd6: Abbe number of the sixth lens at d-ray, and
ih: maximum image height.
2. The imaging lens according to claim 1 , wherein the second lens has convex surfaces facing the object side and the image side, and a conditional expression (4) below is satisfied:
−0.40<( r 3+ r 4)/( r 3− r 4)<0.90 (4)
where
r3: curvature radius of an object-side surface of the second lens, and
r4: curvature radius of an image-side surface of the second lens.
3. The imaging lens according to claim 1 , wherein the third lens has a concave surface facing the image side and aspheric surfaces facing the object side and the image side, the fifth lens has a convex surface facing the image side and aspheric surfaces facing the object side and the image side, and an image-side surface of the sixth lens is concave and has a pole point separated from an optical axis of the imaging lens.
4. The imaging lens according to claim 1 , wherein a conditional expression (2) below is satisfied:
1.0< f 1/ f (2)
where
f1: focal length of the first lens.
5. The imaging lens according to claim 4 , wherein the fourth lens satisfies a conditional expression (5) below:
0.8<| f 4/ f| (5)
where
f4: focal length of the fourth lens.
6. The imaging lens according to claim 1 , wherein a conditional expression (13) below is satisfied:
−1.7< f 2/ f 3<−0.5 (13)
where
f2: focal length of the second lens, and
f3: focal length of the third lens.
7. The imaging lens according to claim 1 , wherein a conditional expression (14) below is satisfied:
−2.3< f 5/ f 6<−0.6 (14)
where
f5: focal length of the fifth lens, and
f6: focal length of the sixth lens.
8. The imaging lens according to claim 1 , wherein the first lens, the second lens, and the third lens respectively satisfy conditional expressions (6) to (8) below:
50<ν d 1<80 (6)
50<ν d 2<80 (7)
20<ν d 3<30 (8)
where
νd1: Abbe number of the first lens at d-ray,
νd2: Abbe number of the second lens at d-ray, and
νd3: Abbe number of the third lens at d-ray.
9. An imaging lens for a solid-state imaging sensor, comprising, in order from an object side to an image side of the imaging lens:
a first lens having positive or negative refractive power;
a second lens having positive refractive power and convex surfaces facing the object side and the image side;
a third lens that is a meniscus lens having a concave surface facing the image side;
a fourth lens that is a meniscus lens having aspheric surfaces facing the object side and the image side;
a fifth lens; and
a sixth lens having negative refractive power and aspheric surfaces facing the object side and the image side,
wherein conditional expressions (6), (11), and (12a) below are satisfied:
50<ν d 1<80 (6)
50<ν d 6<80 (11)
0.85< ih/f< 1.1 (12a)
where
νd1: Abbe number of the first lens at d-ray,
νd6: Abbe number of the sixth lens at d-ray,
ih: maximum image height, and
f: overall focal length of the imaging lens.
10. The imaging lens according to claim 9 , wherein the second lens has convex surfaces facing the object side and the image side, and a conditional expression (4) below is satisfied:
−0.40<( r 3+ r 4)/( r 3− r 4)<0.90 (4)
where
r3: curvature radius of an object-side surface of the second lens, and
r4: curvature radius of an image-side surface of the second lens.
11. The imaging lens according to claim 9 , wherein the fourth lens satisfies a conditional expression (5) below:
0.8<| f 4/ f| (5)
where
f4: focal length of the fourth lens.
12. The imaging lens according to claim 9 , wherein a conditional expression (13) below is satisfied:
−1.7< f 2/ f 3<−0.5 (13)
where
f2: focal length of the second lens, and
f3: focal length of the third lens.
13. The imaging lens according to claim 9 , wherein a conditional expression (14) below is satisfied:
−2.3< f 5/ f 6<−0.6 (14)
where
f5: focal length of the fifth lens, and
f6: focal length of the sixth lens.
14. The imaging lens according to claim 9 , wherein the second lens and the third lens respectively satisfy conditional expressions (7) and (8) below:
50<ν d 2<80 (7)
20<ν d 3<30 (8)
where
νd2: Abbe number of the second lens at d-ray, and
νd3: Abbe number of the third lens at d-ray.
15. An imaging lens for a solid-state imaging sensor, comprising, in order from an object side to an image side of the imaging lens:
a first lens having positive refractive power;
a second lens having positive refractive power and convex surfaces facing the object side and the image side;
a third lens;
a fourth lens having aspheric surfaces facing the object side and the image side;
a fifth lens; and
a sixth lens that is a meniscus lens having negative refractive power and aspheric surfaces facing the object side and the image side,
wherein a conditional expression (12a) below is satisfied:
0.85< ih/f< 1.1 (12a)
where
ih: maximum image height, and
f: overall focal length of the imaging lens.
16. The imaging lens according to claim 15 , wherein the second lens has convex surfaces facing the object side and the image side, and a conditional expression (4) below is satisfied:
−0.40<( r 3+ r 4)/( r 3− r 4)<0.90 (4)
where
r3: curvature radius of an object-side surface of the second lens, and
r4: curvature radius of an image-side surface of the second lens.
17. The imaging lens according to claim 15 , wherein the third lens has a concave surface facing the image side and aspheric surfaces facing the object side and the image side, the fifth lens has a convex surface facing the image side and aspheric surfaces facing the object side and the image side, and an image-side surface of the sixth lens is concave and has a pole point separated from an optical axis of the imaging lens.
18. The imaging lens according to claim 15 , wherein the fourth lens satisfies a conditional expression (5) below:
0.8<| f 4/ f| (5)
where
f4: focal length of the fourth lens.
19. The imaging lens according to claim 15 , wherein a conditional expression (13) below is satisfied:
−1.7< f 2/ f 3<−0.5 (13)
where
f2: focal length of the second lens
f3: focal length of the third lens.
20. The imaging lens according to claim 15 , wherein the first lens, the second lens, and the third lens respectively satisfy conditional expressions (6) to (8) below:
50<ν d 1<80 (6)
50<ν d 2<80 (7)
20<ν d 3<30 (8)
where
νd1: Abbe number of the first lens at d-ray,
νd2: Abbe number of the second lens at d-ray, and
νd3: Abbe number of the third lens at d-ray.