Image pickup lens
An image pickup lens includes a first lens with positive refractive power having a convex object-side surface, a second lens with negative refractive power, a third meniscus lens having a concave image-side surface, a fourth meniscus lens having a convex image-side surface, and a fifth lens with negative refractive power as a double-sided aspheric lens having a concave object-side and image-side surfaces near an optical axis; wherein following conditional expressions (9) and (12) are satisfied; 1.0<|( r 3+ r 4)/( r 3− r 4)|<1.3 (9) −1.1< f 2/ f <−0.7 (12) where r3 represents a curvature radius of an object-side surface of the second lens, r4 represents a curvature radius of an image-side surface of the second lens, f represents a focal length of an overall optical system of the image pickup lens, and f2 represents a focal length of the second lens.
1. An image pickup lens composed of five lenses for a solid imaging element, comprising, in order from an object side to an image side, a first lens having a positive refractive power with a convex surface facing the object side, a second lens having a negative refractive power, a third lens as a meniscus lens with a concave surface facing the image side, a fourth lens as a meniscus lens with a convex surface facing the image side, and a fifth lens having both sides formed as aspherical surfaces and having a negative refractive power with a concave surface facing the object side and the image side near an optical axis;
wherein conditional expressions (9) and (12) below are satisfied:
1.0<|( r 3+ r 4)/( r 3− r 4)|<1.3 (9)
−1.1< f 2/ f<− 0.7 (12)
where r3 represents a curvature radius of an object-side surface of the second lens, r4 represents a curvature radius of an image-side surface of the second lens, f represents a focal length of the overall optical system of the image pickup lens, and f2 represents a focal length of the second lens.
2. The image pickup lens according to claim 1 , wherein an aperture stop is arranged between the first lens and the second lens.
3. The image pickup lens according to claim 1 , wherein the second lens has a negative refractive power and a meniscus shape with a convex surface on the image side.
4. The image pickup lens according to claim 1 , wherein the third lens and the fourth lens each have a positive refractive power.
5. The image pickup lens according to claim 1 , satisfying the following conditional expressions (1), (2), and (3)
50<ν1<85 (1)
20<ν2<35 (2)
1.55< Nd 2<1.70 (3)
where ν1 represents an Abbe number of the first lens, ν2 represents an Abbe number of the second lens, and Nd2 represents a refractive index of the second lens at d-ray.
6. The image pickup lens according to claim 1 , satisfying the following conditional expressions (5), (6), and (7):
20<ν3<30 (5)
50<ν4<60 (6)
1.5 <Nd 3<1.7 (7)
where ν3 represents an Abbe number of the third lens, ν4 represents an Abbe number of the fourth lens, and Nd3 represents a refractive index of the third lens at d-ray.
7. The image pickup lens according to claim 1 , wherein the image-side aspheric surface of the fifth lens has a pole-change point off the optical axis.
8. The image pickup lens according to claim 1 , satisfying the following conditional expression (10):
1.7< r 2/ r 3<6.0 (10)
where r2 represents a curvature radius of an image-side surface of the first lens, and r3 represents a curvature radius of the object-side surface of the second lens.
9. The image pickup lens according to claim 1 , satisfying the following conditional expression (11):
0.5< f 1/ f< 0.8 (11)
where f represents a focal length of the overall optical system of the image pickup lens, and f1 represents a focal length of the first lens.
10. The image pickup lens according to claim 1 , satisfying the following conditional expression (13):
0.5< f 4/ f< 0.7 (13)
where f represents a focal length of the overall optical system of the image pickup lens, and f4 represents a focal length of the fourth lens.