Back to results
US 7,079,326 B2Granted
Zoom lens, camera, and portable information terminal apparatus
AssigneeRicoh Company, Ltd.
InventorMakoto Hirakawa
Life of this patent
Estimating the term…
Abstract
A lens (1), a lens (2) and a lens (3) constitute a first group of lenses, a lens (4), a lens (5), a lens (6) and a lens (7) constitute a second group of lenses, and a lens (8) constitutes a third group of lenses in a zoom lens of the present invention. The second group of lenses is constituted by a first positive lens (4), a negative lens (5) which is in a meniscus shape which faces its convex shape toward a side of an object (70), a second positive lens (6) in a meniscus shape which faces its convex shape toward the object (70) side, and the third positive lens (7), which are in order from the object (70) side.
Claims24
A zoom lens, comprising:
- a first group of lenses, a second group of lenses and a third group of lenses which are subsequently arranged from an object side to an image side;
- said first group of lenses having negative refractive power, said second group of lenses having positive refractive power and said third group of lenses having positive refractive power;
- and
- an aperture stop provided at the object side of said second group of lenses,
- wherein when zooming from a short focal end to a long focal end is carried out, said second group of lenses moves monotonously from the image side to the object side and said first group of lenses moves so as to correct displacement of an image plane position caused in accordance with the zooming,
- said first group of lenses includes one positive lens and two negative lenses,
- said second group of lenses includes three positive lenses and one negative lens, and
- at least the positive lens in said second group of lenses positioned nearest to the image side is a plastic aspheric lens.
5 more elements
A camera, comprising:
- a zoom lens as a photographing optical system;
- said zoom lens being comprised of a first group of lenses, a second group of lenses and a third group of lenses which are subsequently arranged from an object side to an image side;
- said first group of lenses having negative refractive power, said second group of lenses having positive refractive power and said third group of lenses having positive refractive power;
- and
- an aperture stop provided at the object side of said second group of lenses,
- wherein when zooming from a short focal end to a long focal end is carried out, said second group of lenses moves monotonously from the image side to the object side and said first group of lenses moves so as to correct displacement of an image plane position caused in accordance with the zooming,
- said first group of lenses has one positive lens and two negative lenses,
- said second group of lenses includes three positive lenses and one negative lens, and
- at least the positive lens in said second group of lenses positioned nearest to the image side is a plastic aspheric lens.
6 more elements
A portable information terminal apparatus, comprising:
- a zoom lens as a photographing optical system of a camera function section;
- said zoom lens being comprised of a first group of lenses, a second group of lenses and a third group of lenses which are subsequently arranged from an object side to an image side;
- said first group of lenses having negative refractive power, said second group of lenses having positive refractive power and said third group of lenses having positive refractive power;
- and
- an aperture stop provided at the object side of said second group of lenses,
- wherein when zooming from a short focal end to a long focal end is carried out, said second group of lenses moves monotonously from the image side to the object side and said first group of lenses moves so as to correct displacement of an image plane position caused in accordance with the zooming,
- said first group of lenses has one positive lens and two negative lenses,
- said second group of lenses includes three positive lenses and one negative lens, and
- at least the positive lens in said second group of lenses positioned nearest to the image side is a plastic aspheric lens.
6 more elements
A zoom lens, comprising:
- a first group of lenses, a second group of lenses and a third group of lenses which are subsequently arranged from an object side to an image side;
- said first group of lenses having negative refractive power, said second group of lenses having positive refractive power and said third group of lenses having positive refractive power;
- and
- an aperture stop provided at the object side of said second group of lenses,
- wherein when zooming from a short focal end to a long focal end is carried out, said second group of lenses moves monotonously from the image side to the object side and said first group of lenses moves so as to correct displacement of an image plane position caused in accordance with the zooming,
- said second group of lenses includes three positive lenses and one negative lens,
- said negative lens in said second group of lenses is a negative meniscus lens having a convex surface facing toward the object side and one of said three positive lenses in said second group of lenses is a positive meniscus lens having a convex surface facing toward the object side,
- said negative meniscus lens of said second group of lenses and said positive meniscus lens of said second group of lenses are jointed, and
- at least the positive lens in said second group of lenses positioned nearest to the image side is a plastic aspheric lens.
6 more elements
A camera, comprising:
- a zoom lens as a photographing optical system;
- said zoom lens being comprised of a first group of lenses, a second group of lenses and a third group of lenses which are subsequently arranged from an object side to an image side;
- said first group of lenses having negative refractive power, said second group of lenses having positive refractive power and said third group of lenses having positive refractive power;
- and
- an aperture stop provided at the object side of said second group of lenses,
- wherein when zooming from a short focal end to a long focal end is carried out, said second group of lenses moves monotonously from the image side to the object side and said first group of lenses moves so as to correct displacement of an image plane position caused in accordance with the zooming,
- said second group of lenses includes three positive lenses and one negative lens,
- said negative lens in said second group of lenses is a negative meniscus lens having a convex surface facing toward the object side and one of said three positive lenses in said second group of lenses is a positive meniscus lens having a convex surface facing toward the object side,
- said negative meniscus lens of said second group of lenses and said positive meniscus lens of said second group of lenses are jointed, and
- at least the positive lens in said second group of lenses positioned nearest to the image side is a plastic aspheric lens.
7 more elements
A portable information terminal apparatus, comprising:
- a zoom lens as a photographing optical system of a camera function section;
- said zoom lens being comprised of a first group of lenses, a second group of lenses and a third group of lenses which are subsequently arranged from an object side to an image side;
- said first group of lenses having negative refractive power, said second group of lenses having positive refractive power and said third group of lenses having positive refractive power;
- and
- an aperture stop provided at the object side of said second group of lenses,
- wherein when zooming from a short focal end to a long focal end is carried out, said second group of lenses moves monotonously from the image side to the object side and said first group of lenses moves so as to correct displacement of an image plane position caused in accordance with the zooming,
- said second group of lenses includes three positive lenses and one negative lens,
- said negative lens in said second group of lenses is a negative meniscus lens having a convex surface facing toward the object side and one of said three positive lenses in said second group of lenses is a positive meniscus lens having a convex surface facing toward the object side,
- said negative meniscus lens of said second group of lenses and said positive meniscus lens of said second group of lenses are jointed, and
- at least the positive lens in said second group of lenses positioned nearest to the image side is a plastic aspheric lens.
7 more elements
Dependencies are inferred from the claim text.