Imaging lens
AssigneeFujinon Corporation
InventorMinoru Taniyama
Life of this patent
Estimating the term…
Abstract
An imaging lens is provided and includes: in order from an object side of the imaging lens, an aperture diaphragm; 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; and a third lens having a meniscus shape having a convex surface on the object side in the vicinity of an optical axis thereof, each of the first lens, the second lens and the third lens having at least one aspherical surface, and the imaging lens satisfying the following conditional expressions. 0.9<|f2/f|<11 (1) 1.2<|f3/f|<100 (2) f represents a focal length of the imaging lens; f2 represents a focal length of the second lens; and f3 represents a focal length of the third lens.
Claims17
An imaging system comprising:
- in order from an object side of the imaging system,
- an aperture diaphragm;
- and
- an imaging lens consisting of a first lens, a second lens and a third lens,
- said first lens having a positive refractive power and having a convex surface on the object sides,
- said second lens having a negative refractive power and having a concave surface on the object side,
- said third lens having a meniscus shape having a convex surface on the object side in the vicinity of an optical axis thereof, the third lens having a negative refractive power in the vicinity of the optical axis thereof,
- each of the first lens, the second lens and the third lens having at least one aspherical surface, and
- the imaging lens satisfying conditional expressions:
- 0.9<|f2/f|<11 (1)
- 1.2<|f3/f|<100 (2)
- wherein
- f represents a focal length of the imaging lens;
- f2 represents a focal length of the second lens;
- and
- f3 represents a focal length of the third lens.
An imaging system comprising:
- in order from an object side of the imaging system,
- an aperture diaphragm;
- 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;
- and
- a third lens having a meniscus shape having a convex surface on the object side in the vicinity of an optical axis thereof, the third lens having a negative refractive power in the vicinity of the optical axis thereof,
- each of the first lens, the second lens and the third lens having at least one aspherical surface,
- the imaging lens satisfying conditional expressions:
- 0.9<|f2/f|<11 (1)
- 1.2<|f3/f|<100 (2)
- wherein
- f represents a focal length of the imaging lens;
- f2 represents a focal length of the second lens;
- and
- f3 represents a focal length of the third lens,
- wherein said aperture diaphragm is placed on at a position closer to an image side than an object-side plane apex position of the first lens.
An imaging system comprising:
- in order from an object side of the imaging system,
- an aperture diaphragm;
- 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;
- and
- a third lens having a meniscus shape having a convex surface on the object side in the vicinity of an optical axis thereof, the third lens having a negative refractive power in the vicinity of the optical axis thereof,
- each of the first lens, the second lens and the third lens having at least one aspherical surface,
- the imaging lens satisfying conditional expressions:
- 0.9<|f2/f|<11 (1)
- 1.2<|f3/f|<100 (2)
- wherein
- f represents a focal length of the imaging lens;
- f2 represents a focal length of the second lens;
- and
- f3 represents a focal length of the third lens,
- wherein the first lens has a meniscus shape, and the image-side surface of the first lens has a convex shape toward the image side at a peripheral portion.
Dependencies are inferred from the claim text.