Imaging lens
There is provided an imaging lens with high-resolution which realizes reducing size, the low-profileness, low F-number and small telephoto ratio. An imaging lens comprising in order from an object side to an image side, a first lens having positive refractive power, a second lens, a third lens, a fourth lens, a fifth lens having the positive refractive power, and a sixth lens, wherein a below conditional expression is satisfied: 0.6<TTL/ f <1.0 where TTL: total track length, and f: focal length of the overall optical system.
1. An imaging lens comprising in order from an object side to an image side,
a first lens having positive refractive power,
a second lens,
a third lens,
a fourth lens having negative refractive power and a concave surface facing the object side near an optical axis,
a fifth lens having the positive refractive power, and
a sixth lens having a concave surface facing the object side near the optical axis, wherein below conditional expressions (2), (11) and (16) are satisfied:
0.7 <|r 11 |/f <2.0 (2)
0.2 <f 1/ f< 0.8 (11)
20 <vd 4 −v 5<50 (16)
where
f: focal length of the overall optical system,
r11: curvature radius of the object-side surface of the sixth lens L 6 ,
f1: focal length of the first lens,
vd4: abbe number at d-ray of a fourth lens, and
vd5: abbe number at d-ray of a fifth lens.
2. An imaging lens comprising in order from an object side to an image side,
a first lens having convex surfaces facing the object side and the image side and positive refractive power,
a second lens,
a third lens,
a fourth lens,
a fifth lens having convex surfaces facing the object side and the image side and the positive refractive power, and
a sixth lens having a concave surface facing the object side near the optical axis, wherein below conditional expressions (3), (7) and (8) are satisfied:
10<( t 3 /f )×100<20 (3)
1.0< t 3 /t 4<3.2 (7)
20< vd 1 −vd 2<50 (8)
where
f: focal length of the overall optical system,
t3: distance along the optical axis from the image-side surface of the third lens to the object-side surface of the fourth lens,
t4: distance along the optical axis from the image-side surface of the fourth lens to the object-side surface of the fifth lens,
vd1: abbe number at d-ray of a first lens,
vd2: abbe number at d-ray of a second lens.
3. An imaging lens according to claim 1 , wherein said fourth lens has a convex image-side surface near the optical axis and a below conditional expression (4) is satisfied:
0 <r 7 /r 8<0.4 (4)
where
r7: curvature radius of the object-side surface of the fourth lens, and
r8: curvature radius of the image-side surface of the fourth lens.
4. An imaging lens according to claim 1 , wherein a below conditional expression (5) is satisfied:
1.5 <|r 3 |f <32.0 (5)
where
r3: curvature radius of the object-side surface of the second lens.
5. An imaging lens according to claim 1 , wherein a below conditional expression (6) is satisfied:
−2.0 <f 6 /f< −1.0 (6)
where
f6: focal length of the sixth lens.
6. An imaging lens according to claim 1 , wherein a below conditional expression (7) is satisfied:
1.0 <t 3 /t 4<3.2 (7)
where
t3: distance along the optical axis from the image-side surface of the third lens to the object-side surface of the fourth lens, and
t4: distance along the optical axis from the image-side surface of the fourth lens to the object-side surface of the fifth lens.
7. An imaging lens according to claim 1 , wherein a below conditional expression (8) is satisfied:
20 <vd 1 −vd 2<50 (8)
where
vd1: abbe number at d-ray of a first lens, and
vd2: abbe number at d-ray of a second lens.
8. An imaging lens according to claim 1 , wherein a below conditional expression (9) is satisfied:
0.45<( EPsd ×TTL)/( ih×f )<0.75 (9)
where
EPsd: entrance pupil radius, and
Ih: maximum image height.
9. An imaging lens according to claim 1 , wherein a below conditional expression (10) is satisfied:
2.0 <|r 9 |/f< 7.0 (10)
where
r9: curvature radius of the object-side surface of the fifth lens.
10. An imaging lens according to claim 1 , wherein said second lens has a concave image-side surface near the optical axis and a below conditional expression (12) is satisfied:
−1.5 <f 2 /f< −0.4 (12)
where
f2: focal length of the first lens.
11. An imaging lens according to claim 1 , wherein a below conditional expression (13) is satisfied:
0.15 <d 1 /f< 0.25 (13)
where
d1: thickness on the optical axis of the first lens.
12. An imaging lens according to claim 1 , wherein a below conditional expression (14) is satisfied:
−1.7 <f 4 /f <−0.6 (14)
where
f4: focal length of the fourth lens.
13. An imaging lens according to claim 1 , wherein a below conditional expression (15) is satisfied:
0.15 <bf /TTL<0.25 (15)
where
bf: distance along the optical axis from the image-side surface of the sixth lens to an image plane.
14. An imaging lens according to claim 2 , wherein said fourth lens has a convex image-side surface near the optical axis and a below conditional expression (4) is satisfied:
0 <r 7 /r 8<0.4 (4)
where
r7: curvature radius of the object-side surface of the fourth lens, and
r8: curvature radius of the image-side surface of the fourth lens.
15. An imaging lens according to claim 2 , wherein a below conditional expression (5) is satisfied:
1.5 <|r 3 |/f <32.0 (5)
where
r3: curvature radius of the object-side surface of the second lens.
16. An imaging lens according to claim 2 , wherein a below conditional expression (6) is satisfied:
−2.0 <f 6 /f <−1.0 (6)
where
f6: focal length of the sixth lens.
17. An imaging lens according to claim 2 , wherein a below conditional expression (9) is satisfied:
0.45<( Epsd ×TTL)/( ih×f )<0.75 (9)
where
EPsd: entrance pupil radius, and
Ih: maximum image height.
18. An imaging lens according to claim 1 , wherein a below conditional expression (1) is satisfied:
0.6<TTL/ f <1.0 (1)
where
TTL: total track length.
19. An imaging lens according to claim 2 , wherein a below conditional expression (1) is satisfied:
0.6<TTL/ f <1.0 (1)
where
TTL: total track length.