Imaging lens and imaging device
View Patent ↗It is provided that an imaging lens having satisfactory optical performances and being reduced in size and cost. The imaging lens includes in order from an object side, a negative first lens, a negative second lens, a positive third lens, a stop, a positive fourth lens and a negative fifth lens L 5 . And the focal length f3 of the third lens at d-line, the focal length f of the whole system at d-line satisfy 3.0<f3/f<4.5.
1. An imaging lens comprising, in order from an object side:
an imaging lens sequence consisting of a first lens, a second lens, a third lens, a fourth lens and a fifth lens, said first lens being a negative lens, said second lens being a negative lens, said third lens being a positive lens, said fourth lens being a positive lens, and said fifth lens being a negative lens; and
a stop located between the third lens and the fourth lens,
wherein the following Conditional Expression (1) is satisfied:
3.0 <f 3 /f< 4.5 (1)
where f3 denotes a focal length of the third lens, and f denotes a focal length of the imaging lens.
2. The imaging lens according to claim 1 ,
wherein the following Conditional Expression (2) is satisfied:
ν3<45 (2)
where ν 3 denotes an Abbe number of the third lens at the d-line.
3. The imaging lens according to claim 2 ,
wherein the following Conditional Expression (3) is satisfied:
2.5<( D 4 +D 5)/ f< 5.5 (3)
where D 4 denotes a spacing between the second lens and the third lens on the optical axis, and D 5 denotes a thickness of the third lens on the optical axis.
4. The imaging lens according to claim 3 ,
wherein the following Conditional Expressions (4) and (5) satisfied:
0.05 <N 5 −N 4<0.40 (4)
1.5<ν4/ν5 (5)
where
N 4 denotes a refractive index of the fourth lens at the d-line,
ν 4 denotes an Abbe number of the fourth lens at the d-line,
N 5 denotes a refractive index of the fifth lens at the d-line, and
ν 5 denotes Abbe number of the fifth lens at the d-line.
5. The imaging lens according to claim 4 ,
wherein the following Conditional Expression (6) is satisfied:
7 <L/f< 14 (6)
where
L denotes a distance on the optical axis from a surface of the first lens on the object side to the image plane.
6. The imaging lens according to claim 1 ,
wherein the following Conditional Expression (3) is satisfied:
2.5<( D 4 +D 5)/ f< 5.5 (3)
where D 4 denotes a spacing between the second lens and the third lens on the optical axis, and
D 5 denotes a thickness of the third lens on the optical axis.
7. The imaging lens according to claim 6 ,
wherein the following Conditional Expressions (4) and (5) satisfied:
0.05 <N 5 −N 4<0.40 (4)
1.5<ν4/ν5 (5)
where
N 4 denotes a refractive index of the fourth lens at the d-line,
ν 4 denotes an Abbe number of the fourth lens at the d-line,
N 5 denotes a refractive index of the fifth lens at the d-line, and
ν 5 denotes Abbe number of the fifth lens at the d-line.
8. The imaging lens according to claim 7 , wherein the following Conditional Expression (6) is satisfied:
7 <L/f< 14 (6)
where
L denotes a distance on the optical axis from a surface of the first lens on the object side to the image plane.
9. The imaging lens according to claim 1 ,
wherein the fourth lens and the fifth lens are cemented to each other.
10. The imaging lens according to claim 9 ,
wherein the following Conditional Expressions (4) and (5) satisfied:
0.05 <N 5 −N 4<0.40 (4)
1.5<ν4/ν5 (5)
where
N 4 denotes a refractive index of the fourth lens at the d-line,
ν 4 denotes an Abbe number of the fourth lens at the d-line,
N 5 denotes a refractive index of the fifth lens at the d-line, and
ν 5 denotes Abbe number of the fifth lens at the d-line.
11. The imaging lens according to claim 10 ,
wherein the following Conditional Expression (6) is satisfied:
7 <L/f< 14 (6)
where
L denotes a distance on the optical axis from a surface of the first lens on the object side to the image plane.
12. The imaging lens according to claim 1 ,
wherein the following Conditional Expressions (4) and (5) satisfied:
0.05 <N 5 −N 4<0.40 (4)
1.5<ν4/ν5 (5)
where
N 4 denotes a refractive index of the fourth lens at the d-line,
ν 4 denotes an Abbe number of the fourth lens at the d-line,
N 5 denotes a refractive index of the fifth lens at the d-line, and
ν 5 denotes Abbe number of the fifth lens at the d-line.
13. The imaging lens according to claim 1 ,
wherein the following Conditional Expression (6) is satisfied:
7 <L/f< 14 (6)
where
L denotes a distance on the optical axis from a surface of the first lens on the object side to the image plane.
14. An imaging device comprising:
an imaging lens of claim 1 ; and
an imaging element that converts an optical image formed by the imaging lens, into an electric signal.
15. An imaging lens comprising, in order from an object side:
an imaging lens sequence consisting of a first lens, a second lens, a third lens, a fourth lens and a fifth lens, said first lens being a negative lens, said second lens being a negative lens, said third lens being a positive lens, said fourth lens being a positive lens, and said fifth lens being a negative lens; and
a diaphragm located between the third lens and the fourth lens,
wherein the following Conditional Expression (2-2) is satisfied:
ν3<31 (2-2)
where
ν 3 denotes an Abbe number of the third lens at the d-line.
16. The imaging lens according to claim 15 ,
wherein the following Conditional Expression (3) is satisfied:
2.5<( D 4 +D 5)/ f< 5.5 (3)
where f denotes a focal length of the imaging lens, D 4 denotes a spacing between the second lens and the third lens on the optical axis, and
D 5 denotes a thickness of the third lens on the optical axis.
17. The imaging lens according to claim 15 ,
wherein the fourth lens and the fifth lens are cemented to each other.
18. The imaging lens according to claim 15 ,
wherein the following Conditional Expressions (4) and (5) satisfied:
0.05 <N 5 −N 4<0.40 (4)
1.5<ν4/ν5 (5)
where
N 4 denotes a refractive index of the fourth lens at the d-line,
ν 4 denotes an Abbe number of the fourth lens at the d-line,
N 5 denotes a refractive index of the fifth lens at the d-line, and
ν 5 denotes Abbe number of the fifth lens at the d-line.
19. The imaging lens according to claim 15 ,
wherein the following Conditional Expression (6) is satisfied:
7 <L/f< 14 (6)
where
f denotes a focal length of the imaging lens and L denotes a distance on the optical axis from a surface of the first lens on the object side to the image plane.
20. An imaging device comprising:
an imaging lens of claim 15 ; and
an imaging element that converts an optical image formed by the imaging lens, into an electric signal.