Imaging lens and imaging device provided with the same
View Patent ↗An imaging lens substantially consists of five lenses consisting of, in order from the object side: a first lens having a positive refractive power with a convex surface toward the object side; a second lens having a negative refractive power and having a meniscus shape with a convex surface toward the image side; a third lens having a positive refractive power and having a meniscus shape with a convex surface toward the image side; a fourth lens having a positive refractive power and having a meniscus shape with a convex surface toward the image side; and a fifth lens having a negative refractive power, wherein an image-side surface of the fifth lens includes a concave surface and at least one inflection point, wherein a predetermined conditional expression is satisfied.
1. An imaging lens consisting of five lenses consisting of, in order from an object side:
a first lens having a positive refractive power with a convex surface toward the object side;
a second lens having a negative refractive power and having a meniscus shape with a convex surface toward the image side in the vicinity of the optical axis;
a third lens having a positive refractive power and having a meniscus shape with a convex surface toward the image side;
a fourth lens having a positive refractive power and having a meniscus shape with a convex surface toward the image side; and
a fifth lens having a negative refractive power, wherein an image-side surface of the fifth lens includes a concave surface and at least one inflection point,
wherein the conditional expression below is satisfied:
1.15< f/f 1<1.7 (1),
where f is a focal length of the entire system, and f1 is a focal length of the first lens.
2. The imaging lens as claimed in claim 1 , wherein the conditional expression below is further satisfied:
−1.48< f/f 45<0 (2),
where f45 is a combined focal length of the fourth lens and the fifth lens.
3. The imaging lens as claimed in claim 2 , wherein the conditional expression below is further satisfied:
−1.25< f/f 45<0 (2-1),
where f45 is a combined focal length of the fourth lens and the fifth lens.
4. The imaging lens as claimed in claim 3 , wherein the conditional expression below is further satisfied:
−1.1< f/f 45<−0.05 (2-2),
where f45 is a combined focal length of the fourth lens and the fifth lens.
5. The imaging lens as claimed in claim 1 , wherein the conditional expression below is further satisfied:
−1.5< f 12/ f 45<0 (3),
where f12 is a combined focal length of the first lens and the second lens, and f45 is a combined focal length of the fourth lens and the fifth lens.
6. The imaging lens as claimed in claim 5 , wherein the conditional expression below is further satisfied:
−1.45< f 12/ f 45<−0.05 (3-1),
where f12 is a combined focal length of the first lens and the second lens, and f45 is a combined focal length of the fourth lens and the fifth lens.
7. The imaging lens as claimed in claim 1 , wherein the conditional expression below is further satisfied:
−0.3< f/f 345<0.35 (4),
where f345 is a combined focal length of the third to the fifth lenses.
8. The imaging lens as claimed in claim 7 , wherein the conditional expression below is further satisfied:
−0.29< f/f 345<0.2 (4-1),
where f345 is a combined focal length of the third to the fifth lenses.
9. The imaging lens as claimed in claim 1 , wherein the conditional expression below is further satisfied:
−0.95< f/f 2<−0.65 (5),
where f2 is a focal length of the second lens.
10. The imaging lens as claimed in claim 9 , wherein the conditional expression below is further satisfied:
−0.9< f/f 2<−0.68 (5-1),
where f2 is a focal length of the second lens.
11. The imaging lens as claimed in claim 1 , wherein the first lens has a meniscus shape.
12. The imaging lens as claimed in claim 1 , further comprising an aperture stop disposed on the object side of the object-side surface of the second lens.
13. The imaging lens as claimed in claim 1 , wherein the fifth lens has a biconcave shape.
14. The imaging lens as claimed in claim 13 , wherein the conditional expression below is further satisfied:
0.05< f/f 3<0.95 (6),
where f3 is a focal length of the third lens.
15. The imaging lens as claimed in claim 14 , wherein the conditional expression below is further satisfied:
0.06< f/f 3<0.9 (6-1),
where f3 is a focal length of the third lens.
16. The imaging lens as claimed in claim 13 , wherein the conditional expression below is further satisfied:
0.48< f/f 4<1.57 (7),
where f4 is a focal length of the fourth lens.
17. The imaging lens as claimed in claim 16 , wherein the conditional expression below is further satisfied:
0.5< f/f 4<1.56 (7-1),
where f4 is a focal length of the fourth lens.
18. The imaging lens as claimed in claim 1 , wherein the conditional expression below is further satisfied:
1.22< f/f 1<1.6 (1-1).
19. The imaging lens as claimed in claim 18 , wherein the conditional expression below is further satisfied:
1.25< f/f 1<1.55 (1-2).
20. An imaging device comprising the imaging lens as claimed in claim 1 .