Imaging lens
An image lens is disclosed. The image lens includes, arranged in succession from the object side to the image side, an aperture stop S 1 , a first lens L 1 having two convex surfaces and having a positive refractive power, a second lens L 2 having a meniscus shape convex toward the object side and having a negative refractive power, a third lens L 3 having a positive refractive power, a fourth lens L 4 having a meniscus shape convex toward the image side and having a positive refractive power, and a fifth lens L 5 having a meniscus shape convex toward the object side and having a negative refractive power.
1. An image lens comprising, arranged in succession from the object side to the image side:
an aperture stop S 1 ;
a first lens L 1 having two convex surfaces and having a positive refractive power;
a second lens L 2 having a meniscus shape convex toward the object side and having a negative refractive power;
a third lens L 3 having a positive refractive power;
a fourth lens L 4 having a meniscus shape convex toward the image side and having a positive refractive power;
a fifth lens L 5 having a meniscus shape convex toward the object side and having a negative refractive power; wherein the following conditions (1)˜(6) are satisfied:
0.66 ≦f 1 /f≦ 0.90 (1)
−1.40 ≦f 2 /f≦− 1.00 (2)
1.80 ≦f 3 /f≦ 7.00 (3)
0.08 ≦|R 1 /R 2|≦0.18 (4)
3.00 ≦|R 3 /R 4|≦6.00 (5)
0.70 ≦|R 5 /R 6|␣4.00 (6)
where,
f is the focal length of the image lens LA;
f 1 is the focal length of the first lens L 1 ;
f 2 is the focal length of the second lens L 2 ;
f 3 is the focal length of the third lens L 3 ;
R 1 is the curvature radius of the object side surface of the first lens L 1 ;
R 2 is the curvature radius of the image side surface of the first lens L 1 ;
R 3 is the curvature radius of the object side surface of the second lens L 2 ;
R 4 is the curvature radius of the image side surface of the second lens L 2 ;
R 5 is the curvature radius of the object side surface of the third lens L 3 ;
R 6 is the curvature radius of the image side surface of the third lens L 3 .
2. The image lens as claimed in claim 1 further satisfying the following conditions (7)˜(8):
0.50 ≦f 4 /f≦ 0.70 (7)
−0.60 ≦f 5 /f≦− 0.40 (8)
Where:
f is the focal length of the image lens LA;
f 4 is the focal length of the fourth lens L 4 ;
f 5 is the focal length of the fifth lens L 5 .
3. The image lens as claimed in claim 2 further satisfying the following conditions (9)˜(10):
0.005 ≦d 2 /f≦ 0.030 (9)
0.065 ≦d 3 /f≦ 0.150 (10)
Where:
f is the focal length of the image lens LA;
d 2 is the axial distance from the image side surface of the first lens L 1 to the object side surface of the second lens L 2 ;
d 3 is the thickness of the second lens L 2 along the optic axis.
4. The image lens as claimed in claim 3 further satisfying the following conditions (11)˜(12):
50 ≦|R 7 /R 8|≦4.00 (11)
4.00 ≦|R 9 /R 10|≦9.00 (12)
Where:
R 7 is the curvature radius of the object side surface of the fourth lens L 4 ;
R 8 is the curvature radius of the image side surface of the fourth lens L 4 ;
R 9 is the curvature radius of the object side surface of the fifth lens L 5 ;
R 10 is the curvature radius of the image side surface of the fifth lens L 5 .