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US 7,453,654 B2Granted
Imaging lens
AssigneeFujinon Corporation
InventorYoshikazu Shinohara
Life of this patent
Estimating the term…
Abstract
An imaging lens is provided and has, in order from the object side, a first lens of a positive lens having a convex surface on the object side thereof; a second lens in a meniscus shape having a concave surface on an image side thereof; a third lens in a meniscus shape having a convex surface on the image side thereof; and a fourth lens of a positive or negative lens, both surfaces of the fourth lens being aspheric and the fourth lens having a concave surface on the image side and in a vicinity of an optical axis of the fourth lens. The Abbe numbers of the first and second lenses as well as the focal distances of the first to fourth lenses satisfies specific conditions.
Claims31
An imaging lens comprising:
- in order from an object side of the imaging lens,
- a first lens of a positive lens having a convex surface on the object side thereof;
- a second lens of a negative lens in a meniscus shape having a concave surface on an image side thereof;
- a third lens of a positive lens in a meniscus shape having a convex surface on the image side thereof;
- and
- a fourth lens of a positive or negative lens, wherein both surfaces of the fourth lens are aspheric and the fourth lens has a concave surface on the image side in a vicinity of an optical axis of the fourth lens,
- wherein the imaging lens satisfies formulae (1) to (4):
- vd1>50 (1)
- vd2<30 (2)
- |f2/f1|>1 (3)
- 0.5<|f3/f4|<1.5 (4)
- wherein
- vd 1 represents an Abbe number of the first lens;
- vd 2 represents an Abbe number of the second lens;
- f1 represents a focal length of the first lens;
- f2 represents a focal length of the second lens;
- f3 represents a focal length of the third lens;
- and
- f4 represents a focal length of the fourth lens.
16 more elements
An imaging lens comprising:
- in order from an object side of the imaging lens,
- a first lens of a positive lens having a convex surface on the object side thereof;
- a second lens in a meniscus shape having a concave surface on an image side thereof;
- a third lens in a meniscus shape having a convex surface on the image side thereof;
- and
- a fourth lens, wherein both surfaces of the fourth lens are aspheric and the fourth lens has a concave surface on the image side in a vicinity of an optical axis of the fourth lens,
- wherein the imaging lens satisfies formulae (1) to (4):
- vd 1>50 (1)
- vd2<30 (2)
- |f2/f1|>1 (3)
- 0.5<|f3/f4|<1.5 (4)
- wherein
- vd 1 represents an Abbe number of the first lens;
- vd 2 represents an Abbe number of the second lens;
- f1 represents a focal length of the first lens;
- f2 represents a focal length of the second lens;
- f3 represents a focal length of the third lens;
- and
- f4 represents a focal length of the fourth lens.
16 more elements
An imaging lens comprising:
- in order from an object side of the imaging lens,
- a first lens of a positive lens having a convex surface on the object side thereof;
- a second lens of a negative lens in a meniscus shape having a concave surface on an image side thereof;
- a third lens of a positive lens in a meniscus shape having a convex surface on the image side thereof;
- and
- a fourth lens of a positive or negative lens, wherein the fourth lens has a concave surface on the image side in a vicinity of an optical axis of the fourth lens,
- wherein the imaging lens satisfies formulae (1) to (4):
- vd 1>50 (1)
- vd2<30 (2)
- |f2/f1|>1 (3)
- 0.5<|f3/f4|<1.5 (4)
- wherein
- vd 1 represents an Abbe number of the first lens;
- vd 2 represents an Abbe number of the second lens;
- f1 represents a focal length of the first lens;
- f2 represents a focal length of the second lens;
- f3 represents a focal length of the third lens;
- and
- f4 represents a focal length of the fourth lens.
16 more elements
An imaging lens comprising:
- in order from an object side of the imaging lens,
- a first lens of a positive lens having a convex surface on the object side thereof;
- a second lens of a negative lens in a meniscus shape having a concave surface on an image side thereof;
- a third lens of a positive lens in a meniscus shape having a convex surface on the image side thereof;
- and
- a fourth lens of a positive or negative lens, wherein both surfaces of the fourth lens are aspheric and the fourth lens has a concave surface on the image side in a vicinity of an optical axis of the fourth lens,
- wherein the imaging lens satisfies formulae (1) to (4):
- vd 1>50 (1)
- vd2<29 (2A)
- |f2/f1|>1 (3)
- 0.5<|f3/f4|<1.5 (4)
- wherein
- vd 1 represents an Abbe number of the first lens;
- vd 2 represents an Abbe number of the second lens;
- f1 represents a focal length of the first lens;
- f2 represents a focal length of the second lens;
- f3 represents a focal length of the third lens;
- and
- f4 represents a focal length of the fourth lens.
16 more elements
An imaging lens comprising:
- in order from an object side of the imaging lens,
- a first lens of a positive lens having a convex surface on the object side thereof;
- a second lens of a negative lens in a meniscus shape having a concave surface on an image side thereof;
- a third lens of a positive lens in a meniscus shape having a convex surface on the image side thereof;
- and
- a fourth lens of a positive or negative lens, wherein both surfaces of the fourth lens are aspheric and the fourth lens has a concave surface on the image side in a vicinity of an optical axis of the fourth lens,
- wherein the imaging lens satisfies formulae (3) to (4):
- |f2/f1|>1 (3)
- 0.5<|f3/f4|<1.5 (4)
- wherein
- f1 represents a focal length of the first lens;
- f2 represents a focal length of the second lens;
- f3 represents a focal length of the third lens;
- and
- f4 represents a focal length of the fourth lens.
12 more elements
Dependencies are inferred from the claim text.