US5805359A — Wide-angle lens system

Claim 1

Independent Claim 181 words

A wide-angle lens system comprising, basically in order from an object side; a first lens group having a negative refracting power; a second lens group having a positive refracting power and including an aperture stop; and a third lens group having a negative refracting power, wherein said second lens group is divided into front and rear sub-groups G 21 , and G 22 , each having a positive refracting power, between which said aperture stop is located, said first lens group comprises at least one negative meniscus lens convex on the object side, said front sub-group of said second lens group comprising at least one set of cemented lenses containing a positive lens and a negative lens, and said rear sub-group of said second lens group comprising at least one set of cemented lenses containing a positive lens and a negative lens, said third lens group comprises at least one negative meniscus lens convex on an image side, an aspherical surface is used in any one of said lens groups, and said wide-angle lens system is a fixed focus lens system.

Claim 2

Dependent Claim 181 words

A wide-angle lens system comprising, basically in order from an object side; a first lens group having a negative refracting power; a second lens group having a positive refracting power and including an aperture stop; and a third lens group having a negative refracting power, wherein said second lens group is divided into front and rear sub-groups G 21 , and G 22 , each having a positive refracting power, between which said aperture stop is located, said first lens group comprises at least one negative meniscus lens convex on the object side, said front sub-group of said second lens group comprising at least one set of cemented lenses containing a positive lens and a negative lens, and said rear sub-group of said second lens group comprising at least one set of cemented lenses containing a positive lens and a negative lens, said third lens group comprises at least one negative meniscus lens convex on an image side, an aspherical surface is used in any one of said lens groups, and said wide-angle lens system is a fixed focus lens system.

Claim 3

Dependent Claim 238 words

A wide-angle lens system comprising, basically in order from an object side; a first lens group having a negative refracting power; a second lens group having a positive refracting power and including an aperture stop; and a third lens group having a negative refracting power, wherein said second lens group is divided into front and rear sub-groups G 21 and G 22 , each having a positive refracting power, between which said aperture stop is located, said first lens group comprises at least one negative meniscus lens convex on the object side, said front sub-group of said second lens group comprising at least one set of cemented lenses containing a positive lens and a negative lens, and said rear sub-group of said second lens group comprising at least one set of cemented lenses containing a positive lens and a negative lens, said third lens group comprises at least one negative meniscus lens convex on an image side, and said wide-angle lens system is a fixed focus lens system in which focusing from an object at infinity on a finite object is effected by an inner focusing method in which said second lens group is moved from a reference position toward the object side without varying the entire length of said wide-angle lens system while the spacing between said first and second lens groups is decreased with an increase in the spacing between said second and third lens groups.

Claim 4

Dependent Claim 238 words

A wide-angle lens system comprising, basically in order from an object side; a first lens group having a negative refracting power; a second lens group having a positive refracting power and including an aperture stop; and a third lens group having a negative refracting power, wherein said second lens group is divided into front and rear sub-groups G 21 and G 22 , each having a positive refracting power, between which said aperture stop is located, said first lens group comprises at least one negative meniscus lens convex on the object side, said front sub-group of said second lens group comprising at least one set of cemented lenses containing a positive lens and a negative lens, and said rear sub-group of said second lens group comprising at least one set of cemented lenses containing a positive lens and a negative lens, said third lens group comprises at least one negative meniscus lens convex on an image side, and said wide-angle lens system is a fixed focus lens system in which focusing from an object at infinity on a finite object is effected by an inner focusing method in which said second lens group is moved from a reference position toward the object side without varying the entire length of said wide-angle lens system while the spacing between said first and second lens groups is decreased with an increase in the spacing between said second and third lens groups.

Claim 5

Dependent Claim 219 words

A wide-angle lens system comprising, basically in order from an object side: a first lens group having a negative refracting power: second lens group having a positive refracting power and including an aperture stop, and a third lens group having a negative refracting power, wherein said second lens group is divided into front and rear sub-groups G 21 and G 22 , each having a positive refracting power, between which said aperture stop is located, said first lens group comprises at least one negative meniscus lens convex on the object side, said front sub-group of said second lens group comprising at least one set of cemented lenses containing a positive lens and a negative lens, and said rear sub-group of said second lens group comprising at least one set of cemented lenses containing a positive lens and a negative lens, said third lens group comprises at least one negative meniscus lens convex on an image side, and said wide-angle lens system is a fixed focus lens system in which focusing from an object at infinity on a finite object is effected by moving the entire system toward the object side and, at the same time, varying the spacings between the respective lens groups or an inner space of a given lens group, so that aberration variations can be corrected.

Claim 6

Dependent Claim 219 words

A wide-angle lens system comprising, basically in order from an object side: a first lens group having a negative refracting power: second lens group having a positive refracting power and including an aperture stop, and a third lens group having a negative refracting power, wherein said second lens group is divided into front and rear sub-groups G 21 and G 22 , each having a positive refracting power, between which said aperture stop is located, said first lens group comprises at least one negative meniscus lens convex on the object side, said front sub-group of said second lens group comprising at least one set of cemented lenses containing a positive lens and a negative lens, and said rear sub-group of said second lens group comprising at least one set of cemented lenses containing a positive lens and a negative lens, said third lens group comprises at least one negative meniscus lens convex on an image side, and said wide-angle lens system is a fixed focus lens system in which focusing from an object at infinity on a finite object is effected by moving the entire system toward the object side and, at the same time, varying the spacings between the respective lens groups or an inner space of a given lens group, so that aberration variations can be corrected.

Claim 7

Dependent Claim 43 words

A wide-angle lens system according to claim 1 or 2, in which the following condition (1) is satisfied: 0.2<-f.sub.1 /f<30 (1) where f 1 is the focal length of the first lens group; and f is the focal length of the entire system.

Claim 8

Dependent Claim 19 words

A wide-angle lens system according to claim 4, in which the following condition (1)' is satisfied: 0.2<-f.sub.1 /f<3 (1)'

Claim 9

Dependent Claim 46 words

A wide-angle lens system according to claim 1 or 2, in which the following condition (2) is satisfied: 0.15<f.sub.1 /f.sub.3 <25 (2) where f 1 is the focal length of the first lens group; and f 3 is the focal length of the third lens group.

Claim 10

Dependent Claim 20 words

A wide-angle lens system according to claim 6, in which the following condition (2)' is satisfied: 0.15<f.sub.1 /f.sub.3 <2.5 (2)'

Claim 11

Dependent Claim 55 words

A wide-angle lens system according to claim 1 or 2, in which the following condition (3) is satisfied: 0.2<f.sub.21 /f.sub.22 <5 (3) where f 21 is the focal length of the front sub-group of the second lens group; and f 22 is the focal length of the rear sub-group of the the second lens group.

Claim 12

Dependent Claim 20 words

A wide-angle lens system according to claim 8, in which the following condition (3)' is satisfied: 0.2<f.sub.21 /f.sub.22 <2 (3)'

Claim 13

Dependent Claim 77 words

A wide-angle lens system according to claim 1, in which the following condition (4) is satisfied: -3<e'/f<20 (4) where f is the focal length of the entire system; and e' is a principal point spacing when the first lens group and the front sub-group of the second lens group are taken as being one lens group and the rear sub-group of the second lens group and the third lens group are taken as being one lens group.

Claim 14

Dependent Claim 69 words

A wide-angle lens system according to claim 3, in which the following condition (4)' is satisfied: -3<e'/f<1 (4)' where f is the focal length of the entire system; and e' is the principal point spacing between a sub-system comprising the first lens group and the front sub-group of the second lens group and a sub-system comprising the rear sub-group of the second lens group and the third lens group.

Claim 15

Dependent Claim 51 words

A wide-angle lens system according to claim 2, in which the following condition (5) is satisfied: 0.03<e.sub.12 /f<1 (5) where f is the focal length of the entire system; and e 12 is the principal point spacing between the first lens group and the front sub-group of the second lens group.

Claim 16

Dependent Claim 44 words

A wide-angle lens system according to claim 3, in which the following condition (6) is satisfied: 0.2<f.sub.12 /f<16 (6) where f 12 is the composite focal length of the first and second lens groups; and f is the focal length of the entire system.

Claim 17

Dependent Claim 51 words

A wide-angle lens system according to claim 3, in which the following condition (7) is satisfied: -5<f.sub.23 /f<12 (7) where f 23 is the composite focal length of the rear sub-group of the second lens group and the third lens group; and f is the focal length of the entire system.

Claim 18

Dependent Claim 181 words

A wide-angle lens system comprising, in order from an object side: a first lens group having a negative refracting power; a second lens group having a positive refracting power and including an aperture stop; and a third lens group having a negative refracting power, wherein said second lens group is divided into front and rear sub-groups G 21 and G 22 , each having a positive refracting power, between which said aperture stop is located, said first lens group comprises at least one negative meniscus lens convex on the object side, said front sub-group of said second lens group comprising at least one set of cemented lenses containing a positive lens and a negative lens, and said rear sub-group of said second lens group comprising at least one set of cemented lenses containing a positive lens and a negative lens, said third lens group comprises at least one negative meniscus lens convex on an image side, an aspherical surface is used in any one of said lens groups, and at least one aspherical surface is used in said first lens group.

Claim 19

Dependent Claim 181 words

A wide-angle lens system comprising, in order from an object side: a first lens group having a negative refracting power; a second lens group having a positive refracting power and including an aperture stop; and a third lens group having a negative refracting power, wherein said second lens group is divided into front and rear sub-groups G 21 and G 22 , each having a positive refracting power, between which said aperture stop is located, said first lens group comprises at least one negative meniscus lens convex on the object side, said front sub-group of said second lens group comprising at least one set of cemented lenses containing a positive lens and a negative lens, and said rear sub-group of said second lens group comprising at least one set of cemented lenses containing a positive lens and a negative lens, said third lens group comprises at least one negative meniscus lens convex on an image side, an aspherical surface is used in any one of said lens groups, and at least one aspherical surface is used in said first lens group.

Claim 20

Dependent Claim 180 words

A wide-angle lens system comprising, in order from an object side: a first lens group having a negative refracting power; a second lens group having a positive refracting power and including an aperture stop; and a third lens group having a negative refracting power, wherein said second lens group is divided into front and rear sub-groups G 21 and G 22 each having a positive refracting power, between which said aperture stop is located, said first lens group comprises at least one negative meniscus lens convex on the object side, said front sub-group of said second lens group comprising at least one set of cemented lenses containing a positive lens and a negative lens, and said rear sub-group of said second lens group comprising at least one set of cemented lenses containing a positive lens and a negative lens, said third lens group comprises at least one negative meniscus lens convex on an image side, an aspherical surface is used in any one of said lens groups, and at least one aspherical surface is used in said second lens group.

Claim 21

Dependent Claim 180 words

A wide-angle lens system comprising, in order from an object side: a first lens group having a negative refracting power; a second lens group having a positive refracting power and including an aperture stop; and a third lens group having a negative refracting power, wherein said second lens group is divided into front and rear sub-groups G 21 and G 22 each having a positive refracting power, between which said aperture stop is located, said first lens group comprises at least one negative meniscus lens convex on the object side, said front sub-group of said second lens group comprising at least one set of cemented lenses containing a positive lens and a negative lens, and said rear sub-group of said second lens group comprising at least one set of cemented lenses containing a positive lens and a negative lens, said third lens group comprises at least one negative meniscus lens convex on an image side, an aspherical surface is used in any one of said lens groups, and at least one aspherical surface is used in said second lens group.

Claim 22

Dependent Claim 22 words

A wide-angle lens system according to claim 1, in which at least one aspherical surface is used in said third lens group.

Claim 23

Dependent Claim 188 words

A wide-angle lens system comprising, in order from an object side: a first lens group having a negative refracting power; a second lens group having a positive refracting power and including an aperture stop; and a third lens group having a negative refracting power, wherein said second lens group is divided into front and rear sub-groups G 21 and G 22 , each having a positive refracting power, between which said aperture stop is located, said first lens group comprises at least one negative meniscus lens convex on the object side, said front sub-group of said second lens group comprising at least one set of cemented lenses containing a positive lens and a negative lens, and said rear sub-group of said second lens group comprising at least one set of cemented lenses containing a positive lens and a negative lens, said third lens group comprises at least one negative meniscus lens convex on an image side, an aspherical surface is used in any one of said lens groups and at least one aspherical surface is used in each of said first lens group and said second lens group.

Claim 24

Dependent Claim 188 words

A wide-angle lens system comprising, in order from an object side: a first lens group having a negative refracting power; a second lens group having a positive refracting power and including an aperture stop; and a third lens group having a negative refracting power, wherein said second lens group is divided into front and rear sub-groups G 21 and G 22 , each having a positive refracting power, between which said aperture stop is located, said first lens group comprises at least one negative meniscus lens convex on the object side, said front sub-group of said second lens group comprising at least one set of cemented lenses containing a positive lens and a negative lens, and said rear sub-group of said second lens group comprising at least one set of cemented lenses containing a positive lens and a negative lens, said third lens group comprises at least one negative meniscus lens convex on an image side, an aspherical surface is used in any one of said lens groups and at least one aspherical surface is used in each of said first lens group and said second lens group.

Claim 25

Dependent Claim 188 words

A wide-angle lens system comprising, in order from an object side: a first lens group having a negative refracting power; a second lens group having a positive refracting power and including an aperture stop; and a third lens group having a negative refracting power, wherein said second lens group is divided into front and rear sub-groups G 21 and G 22 , each having a positive refracting power, between which said aperture stop is located, said first lens group comprises at least one negative meniscus lens convex on the object side, said front sub-group of said second lens group comprising at least one set of cemented lenses containing a positive lens and a negative lens, and said rear sub-group of said second lens group comprising at least one set of cemented lenses containing a positive lens and a negative lens, said third lens group comprises at least one negative meniscus lens convex on an image side, an aspherical surface is used in any one of said lens groups, and at least one aspherical surface is used in each of said second lens group and said third lens group.

Claim 26

Dependent Claim 188 words

A wide-angle lens system comprising, in order from an object side: a first lens group having a negative refracting power; a second lens group having a positive refracting power and including an aperture stop; and a third lens group having a negative refracting power, wherein said second lens group is divided into front and rear sub-groups G 21 and G 22 , each having a positive refracting power, between which said aperture stop is located, said first lens group comprises at least one negative meniscus lens convex on the object side, said front sub-group of said second lens group comprising at least one set of cemented lenses containing a positive lens and a negative lens, and said rear sub-group of said second lens group comprising at least one set of cemented lenses containing a positive lens and a negative lens, said third lens group comprises at least one negative meniscus lens convex on an image side, an aspherical surface is used in any one of said lens groups, and at least one aspherical surface is used in each of said second lens group and said third lens group.

Claim 27

Dependent Claim 188 words

A wide-angle lens system comprising, in order from an object side: a first lens group having a negative refracting power; a second lens group having a positive refracting power and including an aperture stop; and a third lens group having a negative refracting power, wherein said second lens group is divided into front and rear sub-groups G 21 and G 22 , each having a positive refracting power, between which said aperture stop is located, said first lens group comprises at least one negative meniscus lens convex on the object side, said front sub-group of said second lens group comprising at least one set of cemented lenses containing a positive lens and a negative lens, and said rear sub-group of said second lens group comprising at least one set of cemented lenses containing a positive lens and a negative lens, said third lens group comprises at least one negative meniscus lens convex on an image side, an aspherical surface is used in any one of said lens groups, and at least one aspherical surface is used in each of said first lens group and said third lens group.

Claim 28

Dependent Claim 188 words

A wide-angle lens system comprising, in order from an object side: a first lens group having a negative refracting power; a second lens group having a positive refracting power and including an aperture stop; and a third lens group having a negative refracting power, wherein said second lens group is divided into front and rear sub-groups G 21 and G 22 , each having a positive refracting power, between which said aperture stop is located, said first lens group comprises at least one negative meniscus lens convex on the object side, said front sub-group of said second lens group comprising at least one set of cemented lenses containing a positive lens and a negative lens, and said rear sub-group of said second lens group comprising at least one set of cemented lenses containing a positive lens and a negative lens, said third lens group comprises at least one negative meniscus lens convex on an image side, an aspherical surface is used in any one of said lens groups, and at least one aspherical surface is used in each of said first lens group and said third lens group.

Claim 29

Dependent Claim 192 words

A wide-angle lens system comprising, in order from an object side: a first lens group having a negative refracting power; a second lens group having a positive refracting power and including an aperture stop; and a third lens group having a negative refracting power, wherein said second lens group is divided into front and rear sub-groups G 21 and G 22 , each having a positive refracting power, between which said aperture stop is located, said first lens group comprises at least one negative meniscus lens convex on the object side, said front sub-group of said second lens group comprising at least one set of cemented lenses containing a positive lens and a negative lens, and said rear sub-group of said second lens group comprising at least one set of cemented lenses containing a positive lens and a negative lens, said third lens group comprises at least one negative meniscus lens convex on an image side, an aspherical surface is used in any one of said lens groups, and at least one aspherical surface is used in each of said first lens group, said second lens group and said third lens group.

Claim 30

Dependent Claim 192 words

A wide-angle lens system comprising, in order from an object side: a first lens group having a negative refracting power; a second lens group having a positive refracting power and including an aperture stop; and a third lens group having a negative refracting power, wherein said second lens group is divided into front and rear sub-groups G 21 and G 22 , each having a positive refracting power, between which said aperture stop is located, said first lens group comprises at least one negative meniscus lens convex on the object side, said front sub-group of said second lens group comprising at least one set of cemented lenses containing a positive lens and a negative lens, and said rear sub-group of said second lens group comprising at least one set of cemented lenses containing a positive lens and a negative lens, said third lens group comprises at least one negative meniscus lens convex on an image side, an aspherical surface is used in any one of said lens groups, and at least one aspherical surface is used in each of said first lens group, said second lens group and said third lens group.

Claim 31

Dependent Claim 69 words

A wide-angle lens system according to claim 2, wherein when focusing is to be effected from an object at infinity on a finite object, said second lens group is moved from a reference position toward the object while a part of the lens spacing between said front and rear sub-groups G 21 and G 22 forming said second lens group is varied, thereby compensating for aberration variations during focusing.

Claim 32

Dependent Claim 63 words

A wide-angle lens system according to claim 3, wherein aberration variations are compensated for by allowing said first lens group to consist of a negative meniscus lens convex on the object side and a positive lens, and varying the spacing between the lenses forming said first lens group when focusing is to be effected from an object at infinity on a finite object.

Claim 33

Dependent Claim 51 words

A wide-angle lens system according to claim 3, wherein when focusing is to be effected from an object at infinity on a finite object, said first and second lens groups are moved such that the spacing therebetween is decreased, and the spacing between said second and third lens groups is varied.

Claim 34

Dependent Claim 34 words

A wide-angle lens system according to claim 3, wherein when focusing is to be effected from an object at infinity on a finite object, the internal spacing of said second lens group is varied.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2001-09-07	2002-03-09	2002-09-08	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2005-09-07	2006-03-09	2006-09-08	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2009-09-07	2010-03-09	2010-09-08	$7700.00	Window Closed / Lapsed

Wide-angle lens system

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