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US 6,721,106 B2Granted
Taking lens device
AssigneeMinolta Co., Ltd.
InventorsYasushi Yamamoto, Hitoshi Hagimori
Life of this patent
Estimating the term…
Abstract
A optical device has a zoom lens system that is comprised of a plurality of lens units and that achieves zooming by varying unit-to-unit distances and an image sensor that converts an optical image formed by the zoom lens system into an electrical signal. The zoom lens system is comprised of, from the object side, a first lens unit having a negative optical power, a second lens unit having a negative optical power, a third lens unit having a positive optical power, and a fourth lens unit having a positive optical power. The zoom lens system achieves zooming by varying the distances between the first to fourth lens units.
Claims20
An optical device comprising:
- a zoom lens system, comprising a plurality of lens units, which achieves zooming by varying unit-to-unit distances;
- and
- an image sensor for converting an optical image formed by the zoom lens system into an electrical signal,
- wherein the zoom lens system comprises at least, from an object side thereof to an image side thereof, a first lens unit having a negative optical power, a second lens unit having a negative optical power, and a third lens unit having a positive optical power;
- wherein the third lens unit has an aspherical surface at the image side thereof;
- and
- wherein the following conditional formulae are fulfilled:
- −0.6<(|X|−|X0|)/[C0·(N′−N)·f3]<0
- 0.1Ymax≦Y≦0.7Ymax
- wherein
- X represents a surface shape of the aspherical surface;
- X0 represents a surface shape of a reference spherical surface of the aspherical surface;
- C0 represents a curvature of the reference spherical surface of the aspherical surface;
- N represents a refractive index for a d-line of the object-side medium of the aspherical surface;
- N′ represents the refractive index for the d-line of the image-side medium of the aspherical surface;
- f3 represents a focal length of the third lens unit;
- Ymax represents a maximum effective optical path of an aspherical surface;
- and
- Y represents a height in a direction perpendicular to an optical axis.
16 more elements
An optical device comprising:
- a zoom lens system, comprising a plurality of lens units, which achieves zooming by varying unit-to-unit distances;
- and
- an image sensor for converting an optical image formed by the zoom lens system into an electrical signal,
- wherein the zoom lens system comprises at least, from an object side thereof to an image side thereof, a first lens unit having a negative optical power and provided at the most object side of the zoom lens system, a second lens unit having a negative optical power, and a third lens unit having a positive optical power, and
- wherein the following conditional formula is fulfilled:
- 0.5<f1/f2<5
- wherein
- f1 represents a focal length of the first lens unit;
- and
- f2represents a focal length of the second lens unit.
7 more elements
An optical device comprising:
- a zoom lens system, comprising a plurality of lens units, which achieves zooming by varying unit-to-unit distances;
- and
- an image sensor for converting an optical image formed by the zoom lens system into an electrical signal,
- wherein the zoom lens system comprises at least, from an object side thereof to an image side thereof, a first lens unit having a negative optical power, a second lens unit having a negative optical power, and a third lens unit having a positive optical power;
- and
- wherein the following conditional formulae are fulfilled:
- 1.5<|fl2/fw|<4
- 0.058<(tan ωw)2×fw/TLw<0.9
- wherein
- fl2 represents a composite focal length of the first and the second lens units at a wide-angle end;
- tan ωw represents a half view angle at a wide-angle end;
- fw represents a focal length of an entire optical system at the wide-angle end;
- and
- TLw represents a distance from a first vertex to an image plane at the wide-angle end.
11 more elements
An optical device comprising:
- a zoom lens system, comprising a plurality of lens units, which achieves zooming by varying unit-to-unit distances;
- and
- an image sensor for converting an optical image formed by the zoom lens system into an electrical signal,
- wherein the zoom lens system comprises at least, from an object side thereof to an image side thereof, a first lens unit having a negative optical power, a second lens unit having a negative optical power, and a third lens unit having a positive optical power;
- and
- wherein the following conditional formulae is fulfilled:
- 1.5<|fl2/fw|<4
- 10<TLw×Fnt/(fw×tan ωw)<50
- where
- TLw represents a distance from a first vertex to an image plane at a wide-angle end;
- Fnt represents an f-number at a telephoto end;
- fl2 represents a composite focal length of the first and the second lens units at the wide-angle end;
- fw represents a focal length of an entire optical system at the wide-angle end;
- and
- tan ωw represents a half view angle at the wide-angle end.
12 more elements
An optical device comprising:
- a zoom lens system, comprising a plurality of lens units, which achieves zooming by varying unit-to-unit distances;
- and
- an image sensor for converting an optical image formed by the zoom lens system into an electrical signal,
- wherein the zoom lens system comprises at least, from an object side thereof to an image side thereof, a first lens unit having a negative optical power and provided at the most object side of the zoom lens system, a second lens unit having a negative optical power, and a third lens unit having a positive optical power, and
- wherein the lens unit closest to the image side has a positive optical power, said lens unit is comprised of at least one positive lens element and the positive lens element fulfills the following conditional formula:
- 0.05<(CR1−CR2)/(CR1+CR2)<5
- wherein
- CR1 represents a radius of curvature of the object-side surface;
- and
- CR2 represents a radius of curvature of the image-side surface.
7 more elements
An optical device comprising:
- a zoom lens system, comprising a plurality of lens units, which achieves zooming by varying unit-to-unit distances;
- and
- an image sensor for converting an optical image formed by the zoom lens system into an electrical signal,
- wherein the zoom lens system comprises at least, from an object side thereof to an image side thereof, a first lens unit having a negative optical power, a second lens unit having a negative optical power, and a third lens unit having a positive optical power;
- and
- wherein the following conditional formula is fulfilled:
- 04<|fl2/f3|<1.5
- where
- fl2 represents a composite focal length of the first and the second lens units at a wide-angle end;
- and
- f3 represents a focal length of the third lens unit.
8 more elements
An optical device comprising:
- a zoom lens system, comprising a plurality of lens units, which achieves zooming by varying unit-to-unit distances;
- and
- an image sensor for converting an optical image formed by the zoom lens system into an electrical signal,
- wherein the zoom lens system comprises at least, from an object side thereof to an image side thereof, a first lens unit having a negative optical power and provided at the most object side of the zoom lens system, a second lens unit having a negative optical power, a third lens unit having a positive optical power, and a fourth lens unit having a positive optical power;
- and
- wherein said first lens unit through said fourth lens unit are disposed sequentially across a variable air gap.
3 more elements
An optical device comprising:
- a zoom lens system, comprising a plurality of lens units, which achieves zooming by varying unit-to-unit distances;
- and
- an image sensor for converting an optical image formed by the zoom lens system into an electrical signal,
- wherein the zoom lens system comprises at least, from an object side thereof to an image side thereof, a first lens unit having a negative optical power and being provided at the most object side of the zoom lens system, a second lens unit having a negative optical power, a third lens unit having a positive optical power, and a fourth lens unit having a positive optical power;
- and
- wherein the first lens unit is a single lens element.
3 more elements
An optical device comprising:
- a zoom lens system, comprising a plurality of lens units, which achieves zooming by varying unit-to-unit distances;
- and
- an image sensor for converting an optical image formed by the zoom lens system into an electrical signal,
- wherein the zoom lens system comprises at least, from an object side thereof to an image side thereof, a first lens unit having a negative optical power, a second lens unit having a negative optical power, a third lens unit having a positive optical power, and a fourth lens unit having a positive optical power;
- wherein the third lens unit has an aspherical surface at the image side thereof;
- and
- wherein the following conditional formulae is fulfilled:
- −0.6<(|X|−|X0|)/[C0·(N′−N)·f3]<0
- 0.1Ymax≦Y≦0.7Ymax
- wherein
- X represents a surface shape of the aspherical surface;
- X0 represents a surface shape of a reference spherical surface of the aspherical surface;
- C0 represents a curvature of the reference spherical surface of the aspherical surface;
- N represents a refractive index for a d-line of the object-side medium of the aspherical surface;
- N′ represents the refractive index for the d-line of the image-side medium of the aspherical surface;
- f3 represents a focal length of the third lens unit;
- Ymax represents a maximum effective optical path of an aspherical surface;
- and
- Y represents a height in a direction perpendicular to an optical axis.
16 more elements
An optical device comprising:
- a zoom lens system, comprising a plurality of lens units, which achieves zooming by varying unit-to-unit distances;
- and
- an image sensor for converting an optical image formed by the zoom lens system into an electrical signal,
- wherein the zoom lens system comprises at least, from an object side thereof to an image side thereof, a first lens unit having a negative optical power, a second lens unit having a negative optical power, a third lens unit having a positive optical power, and a fourth lens unit having a positive optical power;
- and
- wherein the following conditional formulae are fulfilled:
- 1.5<|fl2/fw|<4
- 0.058<(tan ωw)2×fw/TLw<0.9
- wherein
- fl2 represents a composite focal length of the first and the second lens units at a wide-angle end;
- tan ωw represents a half view angle at a wide-angle end;
- fw represents a focal length of an entire optical system at the wide-angle end;
- and
- TLw represents a distance from a first vertex to an image plane at the wide-angle end.
11 more elements
An optical device comprising:
- a zoom lens system, comprising a plurality of lens units, which achieves zooming by varying unit-to-unit distances;
- and
- an image sensor for converting an optical image formed by the zoom lens system into an electrical signal,
- wherein the zoom lens system comprises at least, from an object side thereof to an image side thereof, a first lens unit having a negative optical power, a second lens unit having a negative optical power, a third lens unit having a positive optical power, and a fourth lens unit having a positive optical power;
- and
- wherein the following conditional formulae is fulfilled:
- 1.5<|fl2/fw|<4
- 10<TLw×Fnt/(fw×tan ωw)<50
- where
- TLw represents a distance from a first vertex to an image plane at a wide angle end;
- Fnt represents an f-number at a telephoto end;
- fl2 represents a composite focal length of the first and the second lens units at the wide-angle end;
- fw represents a focal length of an entire optical system at the wide-angle end;
- and
- tan ωw represents a half view angle at the wide-angle end.
12 more elements
An optical device comprising:
- a zoom lens system, comprising a plurality of lens units, which achieves zooming by varying unit-to-unit distances;
- and
- an image sensor for converting an optical image formed by the zoom lens system into an electrical signal,
- wherein the zoom lens system comprises at least, from an object side thereof to an image side thereof, a first lens unit having a negative optical power, a second lens unit having a negative optical power, a third lens unit having a positive optical power, and a fourth lens unit having a positive optical power;
- and
- wherein the following conditional formula is fulfilled:
- 0.4<|fl2/f3|<1.5
- where
- fl2 represents a composite focal length of the first and the second lens units at a wide-angle end;
- and
- f3 represents a focal length of the third lens unit.
8 more elements
Dependencies are inferred from the claim text.