US5483380A — Compact zoom lens system having high zoom ratio a…

Claim 1

Independent Claim 191 words

A compact wide-angle zoom lens system comprising, in order from the object side: a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, which is disposed to face said first lens unit across an air spacing, a third lens unit having a positive refractive power, which is disposed to face said second lens unit across an air spacing, and a fourth lens unit having a negative refractive power, which is disposed to face said third lens unit across an air spacing, wherein, during zooming from a wide end to a tele end, said first and third lens units move together as one unit toward the object side, while said second lens unit moves so that, during its movement from the wide end to a middle focal length position, the spacing between said first and second lens units decreases, whereas, during its movement from the middle focal length position to the tele end, the spacing between said second and third lens units decreases, and said fourth lens unit moves so that the spacing between said fourth lens unit and said third lens unit decreases.

Claim 2

Dependent Claim 191 words

A compact wide-angle zoom lens system comprising, in order from the object side: a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, which is disposed to face said first lens unit across an air spacing, a third lens unit having a positive refractive power, which is disposed to face said second lens unit across an air spacing, and a fourth lens unit having a negative refractive power, which is disposed to face said third lens unit across an air spacing, wherein, during zooming from a wide end to a tele end, said first and third lens units move together as one unit toward the object side, while said second lens unit moves so that, during its movement from the wide end to a middle focal length position, the spacing between said first and second lens units decreases, whereas, during its movement from the middle focal length position to the tele end, the spacing between said second and third lens units decreases, and said fourth lens unit moves so that the spacing between said fourth lens unit and said third lens unit decreases.

Claim 3

Dependent Claim 154 words

A compact wide-angle zoom lens systems comprising, in order from the object side: a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, which is disposed to face said first lens unit across an air spacing, a third lens unit having a positive refractive power, which is disposed to face said second lens unit across an air spacing, an aperture stop, and a fourth lens unit having a negative refractive power, which is disposed to face said third lens unit across an air spacing and said aperture stop, wherein, during zooming from a wide end to a tele end, said first and third lens units move together as one unit toward the object side, while said aperture stop moves together with said third lens unit, and said fourth lens unit moves so that the spacing between said fourth lens unit and said third lens unit decreases.

Claim 4

Dependent Claim 154 words

A compact wide-angle zoom lens systems comprising, in order from the object side: a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, which is disposed to face said first lens unit across an air spacing, a third lens unit having a positive refractive power, which is disposed to face said second lens unit across an air spacing, an aperture stop, and a fourth lens unit having a negative refractive power, which is disposed to face said third lens unit across an air spacing and said aperture stop, wherein, during zooming from a wide end to a tele end, said first and third lens units move together as one unit toward the object side, while said aperture stop moves together with said third lens unit, and said fourth lens unit moves so that the spacing between said fourth lens unit and said third lens unit decreases.

Claim 5

Dependent Claim 26 words

A compact wide-angle zoom lens system according to claim 1 or 2, wherein said third lens unit comprises one double-convex lens, and one negative meniscus lens.

Claim 6

Dependent Claim 60 words

A compact wide-angle zoom lens system according to claim 3, wherein said third lens unit satisfies the following condition (4): 15<ν.sub.d(3P) -ν.sub.d(3N) <22 (4) where ν d (3N) is an average Abbe number of the negative lens in said third lens unit, and ν d (3P) is an average Abbe number of the positive lens in said third lens unit.

Claim 7

Dependent Claim 27 words

A compact wide-angle zoom lens system according to claim 1 or 2, wherein said fourth lens unit comprises one positive meniscus lens, and one negative meniscus lens.

Claim 8

Dependent Claim 60 words

A compact wide-angle zoom lens system according to claim 5, wherein said fourth lens unit satisfies the following condition (5): 7<ν.sub.d(4N) -ν.sub.d(4p) <14 (5) where ν d (4N) is an average Abbe number of the negative lens in said fourth lens unit, and ν d (4P) is an average Abbe number of the positive lens in said fourth lens unit.

Claim 9

Dependent Claim 21 words

A compact wide-angle zoom lens system according to claim 1 or 2, wherein said first lens unit comprises one negative lens.

Claim 10

Dependent Claim 44 words

A compact wide-angle zoom lens system according to claim 7, which satisfies the following condition (6): 0.3<|(r.sub.1 +r.sub.2)/(r.sub.1 -r.sub.2)|<1.0(6) where r 1 and r 2 are the respective curvature radii of object- and image-side surfaces of the negative lens in said first lens unit.

Claim 11

Dependent Claim 22 words

A compact wide-angle zoom lens system according to claim 1 or 2, wherein said second lens unit comprises one negative meniscus lens.

Claim 12

Dependent Claim 45 words

A compact wide-angle zoom lens system according to claim 9, which satisfies the following condition (7): 1.4<|(r.sub.5 +r.sub.6)/(r.sub.5 -r.sub.6)|<2.2(7) where r 5 and r 6 are the respective curvature radii of object- and image-side surfaces of the negative meniscus lens in said second lens unit.

Claim 13

Dependent Claim 27 words

A compact wide-angle zoom lens system according to claim 3, wherein the double-convex lens and the negative meniscus lens in said third lens unit are cemented together.

Claim 14

Dependent Claim 62 words

A compact wide-angle zoom lens system according to claim 11, wherein said third lens unit satisfies the following condition (8): n.sub.d(3N) -n.sub.d(3P) >0.24 (8) where n d (3N) is the refractive index of the negative meniscus lens in said third lens unit G3, and n d (3P) is the refractive index of the double-convex positive lens in said third lens unit G3.

Claim 15

Dependent Claim 39 words

A compact wide-angle zoom lens system according to claim 1 or 2, wherein said second lens unit has such an aspherical surface that the negative power becomes stronger as the distance from the optical axis increases toward the periphery.

Claim 16

Dependent Claim 39 words

A compact wide-angle zoom lens system according to claim 1 or 2, wherein said third lens unit has such an aspherical surface that the negative power becomes stronger as the distance from the optical axis increases toward the periphery.

Claim 17

Dependent Claim 204 words

A compact wide-angle zoom lens systems comprising, in order from the object side: a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, which is disposed to face said first lens unit across an air spacing, a third lens unit having a positive refractive power, which is disposed to face said second lens unit across an air spacing, and a fourth lens unit having a negative refractive power, which is disposed to face said third lens unit across an air spacing, wherein, during zooming from a wide end to a tele end, said first and third lens units move together as one unit toward the object side, while said second lens unit moves so that, during its movement from the wide end to a middle focal length position, the spacing between said first and second lens units decreases, whereas, during its movement from the middle focal length position to the tele end, the spacing between said second and third lens units decreases, and said fourth lens unit moves so that the spacing between said fourth lens unit and said third lens unit decreases, and wherein said compact wide-angle zoom lens system satisfies the following condition (1):

Claim 18

Dependent Claim 204 words

A compact wide-angle zoom lens systems comprising, in order from the object side: a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, which is disposed to face said first lens unit across an air spacing, a third lens unit having a positive refractive power, which is disposed to face said second lens unit across an air spacing, and a fourth lens unit having a negative refractive power, which is disposed to face said third lens unit across an air spacing, wherein, during zooming from a wide end to a tele end, said first and third lens units move together as one unit toward the object side, while said second lens unit moves so that, during its movement from the wide end to a middle focal length position, the spacing between said first and second lens units decreases, whereas, during its movement from the middle focal length position to the tele end, the spacing between said second and third lens units decreases, and said fourth lens unit moves so that the spacing between said fourth lens unit and said third lens unit decreases, and wherein said compact wide-angle zoom lens system satisfies the following condition (1):

Claim 19

Dependent Claim 33 words

2<|f 1 |/F W <1.6 (1) where F w is the focal length of the entire system at the wide end, and f 1 is the focal length of said first lens unit.

Claim 20

Dependent Claim 33 words

2<|f 1 |/F W <1.6 (1) where F w is the focal length of the entire system at the wide end, and f 1 is the focal length of said first lens unit.

Claim 21

Dependent Claim 235 words

A compact wide-angle zoom lens system comprising, in order from the object side: a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, which is disposed to face said first lens unit across an air spacing, a third lens unit having a positive refractive power, which is disposed to face said second lens unit across an air spacing, and a fourth lens unit having a negative refractive power, which is disposed to face said third lens unit across an air spacing, wherein, during zooming from a wide end to a tele end, said first and third lens units move together as one unit toward the object side, while said second lens unit moves so that, during its movement from the wide end to a middle focal length position, the spacing between said first and second lens units decreases, whereas, during its movement from the middle focal length position to the tele end, the spacing between said second and third lens units decreases, and said fourth lens unit moves so that the spacing between said fourth lens unit and said third lens unit decreases, and wherein said compact wide-angle zoom lens system satisfies the following condition (2)): 0.5<|f.sub.4 |/F.sub.W <1.0 (2) where F W is the focal length of the entire system at the wide end, and f 4 is the focal length of said fourth lens unit.

Claim 22

Dependent Claim 235 words

A compact wide-angle zoom lens system comprising, in order from the object side: a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, which is disposed to face said first lens unit across an air spacing, a third lens unit having a positive refractive power, which is disposed to face said second lens unit across an air spacing, and a fourth lens unit having a negative refractive power, which is disposed to face said third lens unit across an air spacing, wherein, during zooming from a wide end to a tele end, said first and third lens units move together as one unit toward the object side, while said second lens unit moves so that, during its movement from the wide end to a middle focal length position, the spacing between said first and second lens units decreases, whereas, during its movement from the middle focal length position to the tele end, the spacing between said second and third lens units decreases, and said fourth lens unit moves so that the spacing between said fourth lens unit and said third lens unit decreases, and wherein said compact wide-angle zoom lens system satisfies the following condition (2)): 0.5<|f.sub.4 |/F.sub.W <1.0 (2) where F W is the focal length of the entire system at the wide end, and f 4 is the focal length of said fourth lens unit.

Claim 23

Dependent Claim 204 words

A compact wide-angle zoom lens system comprising, in order from the object side: a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, which is disposed to face said first lens unit across an air spacing, a third lens unit having a positive refractive power, which is disposed to face said second lens unit across an air spacing, and a fourth lens unit having a negative refractive power, which is disposed to face said third lens unit across an air spacing, wherein, during zooming from a wide end to a tele end, said first and third lens units move together as one unit toward the object side, while said second lens unit moves so that, during its movement from the wide end to a middle focal length position, the spacing between said first and second lens units decreases, whereas, during its movement from the middle focal length position to the tele end, the spacing between said second and third lens units decreases, and said fourth lens unit moves so that the spacing between said fourth lens unit and said third lens unit decreases, and wherein said compact wide-angle zoom lens system satisfies the following condition (3):

Claim 24

Dependent Claim 204 words

A compact wide-angle zoom lens system comprising, in order from the object side: a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, which is disposed to face said first lens unit across an air spacing, a third lens unit having a positive refractive power, which is disposed to face said second lens unit across an air spacing, and a fourth lens unit having a negative refractive power, which is disposed to face said third lens unit across an air spacing, wherein, during zooming from a wide end to a tele end, said first and third lens units move together as one unit toward the object side, while said second lens unit moves so that, during its movement from the wide end to a middle focal length position, the spacing between said first and second lens units decreases, whereas, during its movement from the middle focal length position to the tele end, the spacing between said second and third lens units decreases, and said fourth lens unit moves so that the spacing between said fourth lens unit and said third lens unit decreases, and wherein said compact wide-angle zoom lens system satisfies the following condition (3):

Claim 25

Dependent Claim 30 words

4<f 3 /f 2 <0.7 (3) where f 2 is the focal length of said second lens unit, and f 3 is the focal length of said third lens unit.

Claim 26

Dependent Claim 30 words

4<f 3 /f 2 <0.7 (3) where f 2 is the focal length of said second lens unit, and f 3 is the focal length of said third lens unit.

Claim 27

Dependent Claim 222 words

A compact wide-angle zoom lens system comprising, in order from the object side: a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, which is disposed to face said first lens unit across an air spacing, a third lens unit having a positive refractive power, which is disposed to face said second lens unit across an air spacing, and a fourth lens unit having a negative refractive power, which is disposed to face said third lens unit across an air spacing, wherein, during zooming from a wide end to a tele end, said first and third lens units move together as one unit toward the object side, while said second lens unit moves so that, during its movement from the wide end to a middle focal length position, the spacing between said first and second lens units decreases, whereas, during its movement from the middle focal length position to the tele end, the spacing between said second and third lens units decreases, and said fourth lens unit moves so that the spacing between said fourth lens unit and said third lens unit decreases, and wherein focusing from an infinite object point to a closest focusing distance is effected by moving said second and third lens units together as one unit toward the object side.

Claim 28

Dependent Claim 222 words

A compact wide-angle zoom lens system comprising, in order from the object side: a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, which is disposed to face said first lens unit across an air spacing, a third lens unit having a positive refractive power, which is disposed to face said second lens unit across an air spacing, and a fourth lens unit having a negative refractive power, which is disposed to face said third lens unit across an air spacing, wherein, during zooming from a wide end to a tele end, said first and third lens units move together as one unit toward the object side, while said second lens unit moves so that, during its movement from the wide end to a middle focal length position, the spacing between said first and second lens units decreases, whereas, during its movement from the middle focal length position to the tele end, the spacing between said second and third lens units decreases, and said fourth lens unit moves so that the spacing between said fourth lens unit and said third lens unit decreases, and wherein focusing from an infinite object point to a closest focusing distance is effected by moving said second and third lens units together as one unit toward the object side.

Claim 29

Dependent Claim 185 words

A compact wide-angle zoom lens system comprising, in order from the object side: a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, which is disposed to face said first lens unit across an air spacing, a third lens unit having a positive refractive power, which is disposed to face said second lens unit across an air spacing, an aperture stop, and a fourth lens unit having a negative refractive power, which is disposed to face said third lens unit across an air spacing and said aperture stop, wherein, during zooming from a wide end to a tele end, said first and third lens units move together as one unit toward the object side, while said aperture stop moves together with said third lens unit, and said fourth lens unit moves so that the spacing between said fourth lens unit and said third lens unit decreases, and wherein focusing from an infinite object point to a closest focusing distance is effected by moving said second and third lens units together as one unit toward the object side.

Claim 30

Dependent Claim 185 words

A compact wide-angle zoom lens system comprising, in order from the object side: a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, which is disposed to face said first lens unit across an air spacing, a third lens unit having a positive refractive power, which is disposed to face said second lens unit across an air spacing, an aperture stop, and a fourth lens unit having a negative refractive power, which is disposed to face said third lens unit across an air spacing and said aperture stop, wherein, during zooming from a wide end to a tele end, said first and third lens units move together as one unit toward the object side, while said aperture stop moves together with said third lens unit, and said fourth lens unit moves so that the spacing between said fourth lens unit and said third lens unit decreases, and wherein focusing from an infinite object point to a closest focusing distance is effected by moving said second and third lens units together as one unit toward the object side.

Claim 31

Dependent Claim 49 words

A compact wide-angle zoom lens system according to claim 18 or 19, which satisfies the following condition (9): 1.2<|f.sub.1 |/F.sub.W <1.8 (9) where F W is the focal length of the entire system at the wide end, and f 1 is the focal length of said first lens unit.

Claim 32

Dependent Claim 53 words

A compact wide-angle zoom lens system according to claim 18 or 19, which satisfies the following condition (10): 0.6<f.sub.23 /|f.sub.4 <1.2 (10) where f 23 is the composite focal length of said second and third lens units at the tele end, and f 4 is the focal length of said fourth lens unit.

Claim 33

Dependent Claim 41 words

A compact wide-angle zoom lens system according to claim 18 or 19, wherein said fourth lens unit satisfies the following condition (11): 2.5<β.sub.rT <4.0 (11) where β 4T is the lateral magnification of said fourth lens unit at the tele end.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1999-01-08	1999-07-10	2000-01-09	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2003-01-08	2003-07-10	2004-01-09	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2007-01-08	2007-07-10	2008-01-09	$7700.00	Window Closed / Lapsed

Compact zoom lens system having high zoom ratio and wide view angle

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