IMAGING LENS
First Claim
1. An imaging lens comprising:
- a first lens having positive refractive power;
a second lens having negative refractive power;
a third lens having positive refractive power;
a fourth lens having positive refractive power;
a fifth lens; and
a sixth lens having negative refractive power, arranged in this order from an object side to an image plane side,wherein said second lens is formed in a shape so that a curvature radius of a surface thereof on the object side and a curvature radius of a surface thereof on the image plane side are positive,said sixth lens is formed in a shape so that a curvature radius of a surface thereof on the object side and a curvature radius of a surface thereof on the image plane side are negative, andsaid fourth lens is arranged to be away from the fifth lens by a distance D45 on an optical axis thereof, and said imaging lens has an angle of view 2ω
so that the following conditional expressions are satisfied;
0.03<
D45/f<
0.5
70°
≦
2ω
where f is a focal length of a whole lens system.
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Accused Products
Abstract
An imaging lens includes a first lens having positive refractive power; a second lens having negative refractive power; a third lens having positive refractive power; a fourth lens having positive refractive power; a fifth lens; and a sixth lens having negative refractive power, arranged in this order from an object side to an image plane side. The second lens is formed in a shape so that surfaces on the both sides have positive curvature radii. The sixth lens is formed in a shape so that surfaces on the both sides have negative curvature radii. The fourth lens is arranged to be away from the fifth lens by a specific distance on an optical axis, and the imaging lens has a specific angle of view so that specific conditional expressions are satisfied.
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Citations
20 Claims
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1. An imaging lens comprising:
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a first lens having positive refractive power; a second lens having negative refractive power; a third lens having positive refractive power; a fourth lens having positive refractive power; a fifth lens; and a sixth lens having negative refractive power, arranged in this order from an object side to an image plane side, wherein said second lens is formed in a shape so that a curvature radius of a surface thereof on the object side and a curvature radius of a surface thereof on the image plane side are positive, said sixth lens is formed in a shape so that a curvature radius of a surface thereof on the object side and a curvature radius of a surface thereof on the image plane side are negative, and said fourth lens is arranged to be away from the fifth lens by a distance D45 on an optical axis thereof, and said imaging lens has an angle of view 2ω
so that the following conditional expressions are satisfied;
0.03<
D45/f<
0.5
70°
≦
2ωwhere f is a focal length of a whole lens system. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
where Hmax is a maximum image height of the image plane.
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3. The imaging lens according to claim 1, wherein said sixth lens is formed in the shape so that the surface thereof on the object side has a curvature radius R6f and the surface thereof on the image plane side has a curvature radius R6r so that the following conditional expression is satisfied:
3<
|R6r/R6f|<
150.
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4. The imaging lens according to claim 1, wherein said first lens has a focal length f1 and said second lens has a focal length f2 so that the following conditional expression is satisfied:
−
1.0<
f1/f2<
−
0.1.
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5. The imaging lens according to claim 1, wherein said third lens has a focal length f3 so that the following conditional expression is satisfied:
1<
f3/f<
5.
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6. The imaging lens according to claim 1, wherein said sixth lens has a focal length f6 so that the following conditional expression is satisfied:
−
3.0<
f6/f<
−
0.5.
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7. The imaging lens according to claim 1, wherein said fourth lens has a focal length f4 so that the following conditional expression is satisfied:
0.5<
f4/f<
5.0.
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8. The imaging lens according to claim 1, wherein said third lens has a focal length f3 and said fourth lens has a focal length f4 so that the following conditional expression is satisfied:
0.5<
f3/f4<
4.5.
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9. The imaging lens according to claim 1, wherein said second lens has a focal length f2 so that the following conditional expression is satisfied:
−
2.0<
f2/f<
−
0.5.
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10. The imaging lens according to claim 1, wherein said fourth lens and said fifth lens have a composite focal length f45 so that the following conditional expression is satisfied:
2<
f45/f<
8.
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11. An imaging lens comprising:
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a first lens having positive refractive power; a second lens having negative refractive power; a third lens having positive refractive power; a fourth lens having positive refractive power; a fifth lens; and a sixth lens having negative refractive power, arranged in this order from an object side to an image plane side, wherein said second lens is formed in a shape so that a curvature radius of a surface thereof on the object side and a curvature radius of a surface thereof on the image plane side are positive, said sixth lens is formed in a shape so that a curvature radius of a surface thereof on the object side and a curvature radius of a surface thereof on the image plane side are negative, and said fourth lens is arranged to be away from the fifth lens by a distance D45 on an optical axis thereof, and said sixth lens is formed in the shape so that the surface thereof on the image plane side has a curvature radius R6r so that the following conditional expressions are satisfied;
0.03<
D45/f<
0.5
−
80<
R6r/f<
−
5where f is a focal length of a whole lens system. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
where Hmax is a maximum image height of the image plane.
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13. The imaging lens according to claim 11, wherein said fourth lens and said fifth lens have a composite focal length f45 so that the following conditional expression is satisfied:
2<
f45/f<
8.
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14. The imaging lens according to claim 11, wherein said sixth lens is formed in the shape so that the surface thereof on the object side has a curvature radius R6f so that the following conditional expression is satisfied:
3<
|R6r/R6f|<
150.
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15. The imaging lens according to claim 11, wherein said first lens has a focal length f1 and said second lens has a focal length f2 so that the following conditional expression is satisfied:
−
1.0<
f1/f2<
−
0.1.
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16. The imaging lens according to claim 11, wherein said third lens has a focal length f3 so that the following conditional expression is satisfied:
1<
f3/f<
5.
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17. The imaging lens according to claim 11, wherein said sixth lens has a focal length f6 so that the following conditional expression is satisfied:
−
3.0<
f6/f<
−
0.5.
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18. The imaging lens according to claim 11, wherein said fourth lens has a focal length f4 so that the following conditional expression is satisfied:
0.5<
f4/f<
5.0.
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19. The imaging lens according to claim 11, wherein said third lens has a focal length f3 and said fourth lens has a focal length f4 so that the following conditional expression is satisfied:
0.5<
f3/f4<
4.5.
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20. An imaging lens comprising:
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a first lens having positive refractive power; a second lens having negative refractive power; a third lens having positive refractive power; a fourth lens having positive refractive power; a fifth lens; and a sixth lens having negative refractive power, arranged in this order from an object side to an image plane side, wherein said second lens is formed in a shape so that a curvature radius of a surface thereof on the object side and a curvature radius of a surface thereof on the image plane side are positive, said third lens is formed in a shape so that a curvature radius of a surface thereof on the object side is positive and a curvature radius of a surface thereof on the image plane side is negative, said sixth lens is formed in a shape so that a curvature radius of a surface thereof on the object side and a curvature radius of a surface thereof on the image plane side are negative, and said fourth lens is arranged to be away from the fifth lens by a distance D45 on an optical axis thereof so that the following conditional expression is satisfied;
0.03<
D45/f<
0.5where f is a focal length of a whole lens system.
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Specification