Imaging lens
AssigneeTokyo Visionary Optics Co., Ltd.
InventorKoji Nitta
Life of this patent
Estimating the term…
Abstract
There is provided an imaging lens with excellent optical characteristics which satisfies demand of wide field of view, low profile and low F-number. An imaging lens comprises, in order from an object side to an image side, a first lens with positive or negative refractive power in a paraxial region, a second lens with positive or negative refractive power in a paraxial region, a third lens with positive refractive power in a paraxial region, a fourth lens with negative refractive power in a paraxial region, a fifth lens with positive refractive power in a paraxial region, a sixth lens with positive refractive power in a paraxial region, and a seventh lens with negative refractive power.
Claims7
An imaging lens comprising in order from an object side to an image side,
- a first lens with positive or negative refractive power in a paraxial region,
- a second lens with positive or negative refractive power in a paraxial region,
- a third lens with positive refractive power in a paraxial region,
- a fourth lens with negative refractive power in a paraxial region,
- a fifth lens with positive refractive power in a paraxial region,
- a sixth lens with positive refractive power in a paraxial region, and
- a seventh lens with negative refractive power,
- wherein an image-side surface of said first lens is convex in the paraxial region, an object-side surface of said second lens is convex in the paraxial region, and an image-side surface of said sixth lens is concave in the paraxial region, and
- wherein the following conditional expressions (4) and (5) are satisfied:
- 0.10<vd6/vd7<0.60 (4)
- 0.20<(D1/|f1|)×100<7.50 (5)
- where
- vd6:
- an abbe number at d-ray of the sixth lens,
- vd7:
- an abbe number at d-ray of the seventh lens,
- D1:
- a thickness of the first lens along the optical axis, and
- f1:
- a focal length of the first lens.
Dependencies are inferred from the claim text.