An imaging lens is provided and includes: in order from an object side of the imaging lens, a first lens having a positive refractive power and having a convex surface on the object side; a second lens having a negative refractive power and having a concave surface on the object side; a third lens having a positive refractive power in the vicinity of an optical axis thereof; and a fourth lens of a meniscus lens having a negative refractive power and having a convex surface on the object side, the imaging lens satisfying the specific conditional expressions.
1. An imaging lens comprising: in order from an object side of the imaging lens,
a first lens having a positive refractive power and having a convex surface on the object side;
a second lens having a negative refractive power and having a concave surface on the object side;
a third lens having a positive refractive power; and
a fourth lens of a meniscus lens having a negative refractive power and having a convex surface on the object side,
the imaging lens satisfying conditional expressions:
0.6 <f 1/ f <1.0 (1)
1.45<n1<1.6 (2)
v1>60 (3)
0.4 <|f 2/ f |<1.2 (4)
0.7 <f 3/ f <1.9 (5)
wherein
f represents a focal length of the imaging lens;
f 1 represents a focal length of the first lens;
n 1 represents a refractive index of the first lens at the d-line;
v 1 represents an Abbe number of the first lens at the d-line;
f 2 represents a focal length of the second lens; and
f 3 represents a focal length of a third lens, wherein an absolute value of a radius of curvature of an object side surface of the third lens in the vicinity of the optical axis is smaller than that of an image side surface of the third lens in the vicinity of the optical axis.
2. The imaging lens according to claim 1 , wherein each of the second lens, the third lens, and the fourth lens has at least one aspherical surface.
3. The imaging lens according to claim 2 , wherein the first lens has at least one aspherical surface.
4. The imaging lens according to claim 3 , wherein each of the second lens, the third lens, and the fourth lens is made of a resin material.
5. The imaging lens according to claim 4 , wherein the first lens is made of an optical glass.
6. The imaging lens according to claim 5 , further comprising an aperture diaphragm between a position of an object-side surface of the first lens on the optical axis and a position of an image-side surface of the first lens on the optical axis.
7. The imaging lens according to claim 1 , wherein the first lens has at least one aspherical surface.
8. The imaging lens according to claim 7 , wherein the first lens is made of an optical glass.
9. The imaging lens according to claim 8 , further comprising an aperture diaphragm between a position of an object-side surface of the first lens on the optical axis and a position of an image-side surface of the first lens on the optical axis.
10. The imaging lens according to claim 1 , wherein each of the second lens, the third lens, and the fourth lens is made of a resin material.
11. The imaging lens according to claim 10 , further comprising an aperture diaphragm between a position of an object-side surface of the first lens on the optical axis and a position of an image-side surface of the first lens on the optical axis.
12. The imaging lens according to claim 2 , wherein each of the second lens, the third lens, and the fourth lens is made of a resin material.
13. The imaging lens according to claim 12 , wherein the first lens is made of an optical glass.
14. The imaging lens according to claim 13 , further comprising an aperture diaphragm between a position of an object-side surface of the first lens on the optical axis and a position of an image-side surface of the first lens on the optical axis.
15. The imaging lens according to claim 3 , wherein the first lens is made of an optical glass.
16. The imaging lens according to claim 15 , further comprising an aperture diaphragm between a position of an object-side surface of the first lens on the optical axis and a position of an image-side surface of the first lens on the optical axis.
17. The imaging lens according to claim 1 , further comprising an aperture diaphragm between a position of an object-side surface of the first lens on the optical axis and a position of an image-side surface of the first lens on the optical axis.
18. An imaging lens comprising: in order from an object side of the imaging lens,
a first lens having a positive refractive power and having a convex surface on the object side;
a second lens having a negative refractive power and having a concave surface on the object side;
a third lens having a positive refractive power; and
a fourth lens of a meniscus lens having a negative refractive power and having a convex surface on the object side,
the imaging lens satisfying conditional expressions:
0.6< f 1 /f <1.0 (1)
1.45< n 1<1.6 (2)
v 1>60 (3)
0.4<| f 2/ f|< 1.2 (4)
0.88< f 3/ f< 1.9 (5)
wherein
f represents a focal length of the imaging lens;
f 1 represents a focal length of the first lens;
n 1 represents a refractive index of the first lens at the d-line;
v 1 represents an Abbe number of the first lens at the d-line;
f 2 represents a focal length of the second lens; and
f 3 represents a focal length of a third lens.
19. The imaging lens according to claim 18 , wherein each of the second lens, the third lens, and the fourth lens has at least one aspherical surface.
20. The imaging lens according to claim 19 , wherein the first lens has at least one aspherical surface.
21. The imaging lens according to claim 20 , wherein an absolute value of a radius of curvature of an object-side surface of the third lens in the vicinity of the optical axis is smaller than that of an image-side surface of the third lens in the vicinity of the optical axis.
22. The imaging lens according to claim 21 , wherein each of the second lens, the third lens, and the fourth lens is made of a resin material.
23. The imaging lens according to claim 22 , wherein the first lens is made of an optical glass.
24. The imaging lens according to claim 23 , further comprising an aperture diaphragm between a position of an object-side surface of the first lens on the optical axis and a position of an image-side surface of the first lens on the optical axis.
25. The imaging lens according to claim 18 , wherein the first lens has at least one aspherical surface.
26. The imaging lens according to claim 25 , wherein an absolute value of a radius of curvature of an object-side surface of the third lens in the vicinity of the optical axis is smaller than that of an image-side surface of the third lens in the vicinity of the optical axis.
27. The imaging lens according to claim 26 , wherein the first lens is made of an optical glass.
28. The imaging lens according to claim 27 , further comprising an aperture diaphragm between a position of an object-side surface of the first lens on the optical axis and a position of an image-side surface of the first lens on the optical axis.
29. The imaging lens according to claim 18 , wherein an absolute value of a radius of curvature of an object-side surface of the third lens in the vicinity of the optical axis is smaller than that of an image-side surface of the third lens in the vicinity of the optical axis.
30. The imaging lens according to claim 29 , wherein each of the second lens, the third lens, and the fourth lens is made of a resin material.
31. The imaging lens according to claim 30 , further comprising an aperture diaphragm between a position of an object-side surface of the first lens on the optical axis and a position of an image-side surface of the first lens on the optical axis.
32. The imaging lens according to claim 18 , wherein each of the second lens, the third lens, and the fourth lens is made of a resin material.
33. The imaging lens according to claim 32 , wherein the first lens is made of an optical glass.
34. The imaging lens according to claim 33 , further comprising an aperture diaphragm between a position of an object-side surface of the first lens on the optical axis and a position of an image-side surface of the first lens on the optical axis.
35. The imaging lens according to claim 20 , wherein the first lens is made of an optical glass.
36. The imaging lens according to claim 35 , further comprising an aperture diaphragm between a position of an object-side surface of the first lens on the optical axis and a position of an image-side surface of the first lens on the optical axis.
37. The imaging lens according to claim 18 , further comprising an aperture diaphragm between a position of an object-side surface of the first lens on the optical axis and a position of an image-side surface of the first lens on the optical axis.