US2019187444A1PendingUtilityA1
Zoom lens, optical apparatus and method for manufacturing the zoom lens

Assignee: NIKON CORPPriority: Aug 9, 2013Filed: Nov 16, 2018Published: Jun 20, 2019
Est. expiryAug 9, 2033(~7.1 yrs left)· nominal 20-yr term from priority
Inventors:Daisaku Arai Takamichi Kurashige
G02B 15/20G02B 13/009G02B 13/18G02B 15/14G02B 15/144113G02B 15/144105
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References
Claims
Abstract

Provided is a zoom lens having, in order from an object, a first lens group (G 1 ) having positive refractive power, a second lens group (G 2 ) having negative refractive power, a third lens group (G 3 ) having positive refractive power, and a fourth lens group (G 4 ) having positive refractive power. Upon zooming from a wide-angle end state to a telephoto end state, a distance between the first lens group and the second lens group changes, a distance between the second lens group and the third lens group changes, a distance between the third lens group and the fourth lens group changes, and at least the first lens group (G 1 ) moves. The first lens group (G 1 ) is constituted by a set of cemented lenses, the third lens group (G 3 ) is constituted by, in order from the object, a positive lens and a negative lens, and the conditional expression 0.50<TL/ft<1.28 is satisfied, where TL denotes a total length of the zoom lens (ZL) in the telephoto end state, and ft denotes a focal length of the zoom lens (ZL) in the telephoto end state.
Claims

exact text as granted — not AI-modified
1 - 14 . (canceled) 
     
     
         15 . A zoom lens comprising, in order from an object:
 a first lens group having positive refractive power;   a second lens group having negative refractive power;   a third lens group having positive refractive power; and   a fourth lens group having positive refractive power,   upon zooming from a wide-angle end state to a telephoto end state, a distance between the first lens group and the second lens group changing, a distance between the second lens group and the third lens group changing, a distance between the third lens group and the fourth lens group changing, and at least the first lens group moving, and   the following conditional expressions being satisfied:
   0.1&lt; fG 1/ fG 4&lt;1.0 
   10.0&lt; ft/dG 1&lt;16.0 
   where fG 1  denotes a focal length of the first lens group, fG 4  denotes a focal length of the fourth lens group, ft denotes a focal length of the zoom lens in the telephoto end state, and dG 1  denotes a thickness of the first lens group on the optical axis.   
     
     
         16 . The zoom lens according to  claim 15 , wherein
 the first lens group is constituted by, in order from the object, a lens having negative refractive power and a lens having positive refractive power,   the second lens group is constituted by, in order from the object, a lens having negative refractive power, a lens having negative refractive power, and a lens having positive refractive power, and   the following conditional expressions are satisfied:
   0.050&lt;Σ D 2/ ft&lt; 0.115
 
   4.3&lt; f 4/ fw&lt; 6.8 
   where ΣD 2  denotes a distance on the optical axis from a lens surface closest to the object to a lens surface closest to an image in the second lens group, ft denotes a focal length of the zoom lens in the telephoto end state, fw denotes a focal length of the zoom lens in the wide-angle end state, and f 4  denotes a focal length of the fourth lens group.   
     
     
         17 . The zoom lens according to  claim 15 , wherein
 the first lens group is constituted by, in order from the object, a lens having negative refractive power and a lens having positive refractive power, and   the following conditional expressions are satisfied:
   −0.25&lt; M 2/ fw&lt; 1.10
 
   3.0&lt; fL 2/ fw&lt; 4.5 
   where M 2  denotes a moving distance of the second lens group upon zooming from the wide-angle end state to the telephoto end state (where a direction toward an image plane is positive), fw denotes a focal length of the zoom lens in the wide-angle end state, and fL 2  denotes a focal length of the lens having positive refractive power included in the first lens group.   
     
     
         18 . The zoom lens according to  claim 15 , wherein
 the first lens group is constituted by a negative lens and a positive lens,   the second lens group is constituted by, in order from the object, a negative lens, a negative lens and a positive lens,   the third lens group is constituted by a positive lens and a negative lens, and   the following conditional expressions are satisfied:
   −1.50&lt;( G 2 R 2+ G 2 R 1)/( G 2 R 2− G 2 R 1)&lt;−0.10
 
   −2.00&lt;( G 3 R 2+ G 3 R 1)/( G 3 R 2− G 3 R 1)&lt;−0.50
 
   where G 2 R 1  denotes a radius of curvature of an object side lens surface of the negative lens disposed on an image side of the second lens group, G 2 R 2  denotes a radius of curvature of an image side lens surface of the negative lens disposed on the image side of the second lens group, G 3 R 1  denotes a radius of curvature of an object side lens surface of the negative lens of the third lens group, and G 3 R 2  denotes a radius of curvature of an image side lens surface of the negative lens of the third lens group.   
     
     
         19 . The zoom lens according to  claim 15 , wherein
 the first lens group is constituted by a negative lens and a positive lens.   
     
     
         20 . The zoom lens according to  claim 15 , wherein
 the third lens group is constituted by, in order from the object, a positive lens and a negative lens.   
     
     
         21 . The zoom lens according to  claim 15 , wherein
 the second lens group is constituted by a negative lens, a negative lens and a positive lens.   
     
     
         22 . The zoom lens according to  claim 15 , wherein
 the fourth lens group is constituted by one positive lens.   
     
     
         23 . The zoom lens according to  claim 15 , wherein
 the following conditional expression is satisfied:
   1.00&lt; fG 1/( fw·ft )1/2&lt;2.10 
   where fw denotes a focal length of the zoom lens in the wide-angle end state.   
     
     
         24 . The zoom lens according to  claim 15 , wherein
 upon zooming from the wide-angle end state to the telephoto end state, the fourth lens group moves to an object side first, and then moves to an image side.   
     
     
         25 . The zoom lens according to  claim 15 , wherein
 upon zooming from the wide-angle end state to the telephoto end state, the second lens group moves to an image side first, and then moves to an object side.   
     
     
         26 . The zoom lens according to  claim 15 , wherein
 the third lens group includes at least one aspherical lens.   
     
     
         27 . The zoom lens according to  claim 15 , wherein
 the second lens group includes at least one aspherical lens.   
     
     
         28 . The zoom lens according to  claim 15 , wherein
 the fourth lens group includes at least one aspherical lens.   
     
     
         29 . The zoom lens according to  claim 15 , wherein
 the first lens group includes at least one aspherical lens.   
     
     
         30 . A zoom lens comprising, in order from an object:
 a first lens group having positive refractive power;   a second lens group having negative refractive power;   a third lens group having positive refractive power; and   a fourth lens group having positive refractive power,   upon zooming from a wide-angle end state to a telephoto end state, a distance between the first lens group and the second lens group changing, a distance between the second lens group and the third lens group changing, and a distance between the third lens group and the fourth lens group changing,   the first lens group being constituted by, in order from the object, a lens having negative refractive power and a lens having positive refractive power,   the second lens group being constituted by, in order from the object, a lens having negative refractive power, a lens having negative refractive power and a lens having positive refractive power, and   the following conditional expressions being satisfied:
   0.050&lt;Σ D 2/ ft&lt; 0.115
 
   4.3&lt; f 4/ fw&lt; 6.8 
   where ΣD 2  denotes a distance on the optical axis from a lens surface closest to the object to a lens surface closest to an image in the second lens group, ft denotes a focal length of the zoom lens in the telephoto end state, fw denotes a focal length of the zoom lens in the wide-angle end state, and f 4  denotes a focal length of the fourth lens group.   
     
     
         31 . The zoom lens according to  claim 30 , wherein
 the third lens group is constituted by one single lens having positive refractive power and one single lens having negative refractive power.   
     
     
         32 . The zoom lens according to  claim 30 , wherein
 the following conditional expression is satisfied:
   0.50&lt; TLt/ft&lt; 1.40 
   where TLt denotes a total length of an optical system in the telephoto end state, and ft denotes a focal length of the zoom lens in the telephoto end state.   
     
     
         33 . The zoom lens according to  claim 30 , wherein
 the following conditional expression is satisfied:
   0.16&lt;(− f 2)/ f 1&lt;0.40
 
   where f 1  denotes a focal length of the first lens group, and f 2  denotes a focal length of the second lens group.   
     
     
         34 . The zoom lens according to  claim 30 , wherein
 the following conditional expression is satisfied:
   0.70&lt; f 4/ f 1&lt;1.40 
   where f 1  denotes a focal length of the first lens group, and f 4  denotes a focal length of the fourth lens group.   
     
     
         35 . The zoom lens according to  claim 30 , wherein
 upon zooming from the wide-angle end state to the telephoto end state, the first lens group, the second lens group, the third lens group, and the fourth lens group move.   
     
     
         36 . The zoom lens according to  claim 30 , wherein
 the lens having negative refractive power and the lens having positive refractive power, which constitute the first lens group, are cemented.   
     
     
         37 . The zoom lens according to  claim 30 , wherein
 the lens having negative refractive power, the lens having negative refractive power, and the lens having positive refractive power, which constitute the second lens group, are separated from each other by an air distance.   
     
     
         38 . The zoom lens according to  claim 30 , wherein
 the fourth lens group is constituted by one single lens having positive refractive power.   
     
     
         39 . The zoom lens according to  claim 30 , wherein
 an image side lens surface of the lens having positive refractive power, which constitutes the first lens group, is formed in an aspherical shape.   
     
     
         40 . The zoom lens according to  claim 30 , wherein
 at least one of lens surfaces of the lenses having negative refractive power, which constitute the second lens group, is formed in an aspherical shape.   
     
     
         41 . The zoom lens according to  claim 30 , wherein
 at least one of surfaces of the lenses, which constitute the third lens group, is formed in an aspherical shape.   
     
     
         42 . The zoom lens according to  claim 30 , wherein
 at least one of surfaces of the lenses, which constitute the fourth lens group, is formed in an aspherical shape.   
     
     
         43 . The zoom lens according to  claim 30 , wherein
 a medium of the lenses constituting the fourth lens group is plastic resin.   
     
     
         44 . The zoom lens according to  claim 30 , wherein
 upon focusing from an object at infinity to an object at a close distance, the fourth lens group moves along the optical axis.   
     
     
         45 . A zoom lens comprising, in order from an object,
 a first lens group having positive refractive power;   a second lens group having negative refractive power;   a third lens group having positive refractive power; and   a fourth lens group having positive refractive power,   upon zooming from a wide-angle end state to a telephoto end state, a distance between the first lens group and the second lens group changing, a distance between the second lens group and the third lens group changing, and a distance between the third lens group and the fourth lens group changing,   the first lens group being constituted by, in order from the object, a lens having negative refractive power, and a lens having positive refractive power, and   the following conditional expressions being satisfied:
   −0.25&lt; M 2/ fw&lt; 1.10
 
   3.0&lt; fL 2/ fw&lt; 4.5 
   where M 2  denotes a moving distance of the second lens group upon zooming from the wide-angle end state to the telephoto end state (where a direction toward an image plane is positive), fw denotes a focal length of the zoom lens in the wide-angle end state, and fL 2  denotes a focal length of the lens having positive refractive power included in the first lens group.   
     
     
         46 . The zoom lens according to  claim 45 , wherein
 the third lens group is constituted by one single lens having positive refractive power, and one single lens having negative refractive power.   
     
     
         47 . The zoom lens according to  claim 45 , wherein
 the third lens group includes a lens having negative refractive power, and   the following conditional expression is satisfied:
   −4.5&lt;( R 72+ R 71)/( R 72− R 71)&lt;−0.1
 
   where R 71  denotes a radius of curvature of an object side lens surface of the lens having negative refractive power included in the third lens group, and R 72  denotes a radius of curvature of an image side lens surface of the lens having negative refractive power included in the third lens group.   
     
     
         48 . The zoom lens according to  claim 45 , wherein
 the following conditional expression is satisfied:
   0.50&lt; TLt/ft&lt; 1.40 
   where TLt denotes a total length of an optical system in the telephoto end state, and ft denotes a focal length of the zoom lens in the telephoto end state.   
     
     
         49 . The zoom lens according to  claim 45 , wherein
 the following conditional expression is satisfied:
   0.16&lt;(− f 2)/ f 1&lt;0.40
 
   where f 1  denotes a focal length of the first lens group, and f 2  denotes a focal length of the second lens group.   
     
     
         50 . The zoom lens according to  claim 45 , wherein
 the following conditional expression is satisfied:
   0.70&lt; f 4/ f 1&lt;1.40 
   where f 1  denotes a focal length of the first lens group, and f 4  denotes a focal length of the fourth lens group.   
     
     
         51 . The zoom lens according to  claim 45 , wherein
 the following conditional expression is satisfied:
   4.0&lt; f 1/ fw&lt; 6.5 
   where f 1  denotes a focal length of the first lens group, and fw denotes a focal length of the zoom lens in the wide-angle end state.   
     
     
         52 . The zoom lens according to  claim 45 , wherein
 the following conditional expression is satisfied:
   −0.4&lt; M 3/ ft&lt;− 0.05
 
   where M 3  denotes a moving distance of the third lens group upon zooming from the wide-angle end state to the telephoto end state (where the direction toward the image plane is positive), and ft denotes a focal length of the zoom lens in the telephoto end state.   
     
     
         53 . The zoom lens according to  claim 45 , wherein
 the second lens group is constituted by, in order from the object, a lens having negative refractive power, a lens having negative refractive power, and a lens having positive refractive power.   
     
     
         54 . The zoom lens according to  claim 53 , wherein
 the following conditional expression is satisfied:
   1.55&lt;( R 52+ R 51)/( R 52− R 51)&lt;3.65
 
   where R 51  denotes a radius of curvature of an object side lens surface of the lens disposed closest to an image in the second lens group, and R 52  denotes a radius of curvature of an image side lens surface of the lens disposed closest to the image in the second lens group.   
     
     
         55 . The zoom lens according to  claim 45 , wherein
 the lens having negative refractive power, the lens having negative refractive power, and the lens having positive refractive power, which constitute the second lens group, are separated from each other by an air distance.   
     
     
         56 . The zoom lens according to  claim 45 , wherein
 at least one of lens surfaces of the lenses having negative refractive power, which constitute the second lens group, is formed in an aspherical shape.   
     
     
         57 . The zoom lens according to  claim 45 , wherein
 the lens having negative refractive power and the lens having positive refractive power, which constitute the first lens group, are cemented.   
     
     
         58 . The zoom lens according to  claim 45 , wherein
 upon zooming from the wide-angle end state to the telephoto end state, the first lens group, the second lens group, the third lens group, and the fourth lens group move.   
     
     
         59 . The zoom lens according to  claim 45 , wherein
 the fourth lens group is constituted by a lens having positive refractive power.   
     
     
         60 . The zoom lens according to  claim 45 , wherein
 an image side lens surface of the lens having positive refractive power, which constitutes the first lens group, is formed in an aspherical shape.   
     
     
         61 . The zoom lens according to  claim 45 , wherein
 at least one of surfaces of the lenses, which constitute the third lens group, is formed in an aspherical shape.   
     
     
         62 . The zoom lens according to  claim 45 , wherein
 at least one of surfaces of the lenses, which constitute the fourth lens group, is formed in an aspherical shape.   
     
     
         63 . The zoom lens according to  claim 45 , wherein
 a medium of the lenses constituting the fourth lens group is plastic resin.   
     
     
         64 . The zoom lens according to  claim 45 , wherein
 upon focusing from an object at infinity to an object at a close distance, the fourth lens group moves along the optical axis.   
     
     
         65 . A zoom lens comprising, in order from an object:
 a first lens group having positive refractive power;   a second lens group having negative refractive power;   a third lens group having positive refractive power; and   a fourth lens group having positive refractive power,   upon zooming from a wide-angle end state to a telephoto end state, a distance between the first lens group and the second lens group changing, a distance between the second lens group and the third lens group changing, a distance between the third lens group and the fourth lens group changing, and at least the first lens group moving,   the first lens group being constituted by a negative lens and a positive lens,   the second lens group being constituted by, in order from the object, a negative lens, a negative lens and a positive lens,   the third lens group being constituted by a positive lens and a negative lens, and   the following conditional expressions being satisfied:
   −1.50&lt;( G 2 R 2+ G 2 R 1)/( G 2 R 2− G 2 R 1)&lt;−0.10
 
   −2.00&lt;( G 3 R 2+ G 3 R 1)/( G 3 R 2− G 3 R 1)&lt;−0.50
 
   where G 2 R 1  denotes a radius of curvature of an object side lens surface of the negative lens disposed on an image side of the second lens group, G 2 R 2  denotes a radius of curvature of an image side lens surface of the negative lens disposed on the image side of the second lens group, G 3 R 1  denotes a radius of curvature of an object side lens surface of the negative lens of the third lens group, and G 3 R 2  denotes a radius of curvature of an image side lens surface of the negative lens of the third lens group.   
     
     
         66 . The zoom lens according to  claim 65 , wherein
 the following conditional expression is satisfied:
   1.00&lt; fG 1/( fw·ft )1/2&lt;2.10 
   where fG 1  denotes a focal length of the first lens group, fw denotes a focal length of the zoom lens in the wide-angle end state, and ft denotes a focal length of the zoom lens in the telephoto end state.   
     
     
         67 . The zoom lens according to  claim 65 , wherein
 the fourth lens group is constituted by a positive lens.   
     
     
         68 . The zoom lens according to  claim 65 , wherein
 upon zooming from the wide-angle end state to the telephoto end state, the fourth lens group moves to an object side first, and then moves to an image side.   
     
     
         69 . The zoom lens according to  claim 65 , wherein
 the third lens group includes at least one aspherical lens.   
     
     
         70 . The zoom lens according to  claim 65 , wherein
 the second lens group includes at least one aspherical lens.   
     
     
         71 . The zoom lens according to  claim 65 , wherein
 the fourth lens group includes at least one aspherical lens.   
     
     
         72 . The zoom lens according to  claim 65 , wherein
 the first lens group includes at least one aspherical lens.   
     
     
         73 . (canceled) 
     
     
         74 . An optical apparatus comprising the zoom lens according to  claim 15 . 
     
     
         75 . An optical apparatus comprising the zoom lens according to  claim 30 . 
     
     
         76 . An optical apparatus comprising the zoom lens according to  claim 45 . 
     
     
         77 . An optical apparatus comprising the zoom lens according to  claim 65 . 
     
     
         78 . (canceled) 
     
     
         79 . A method for manufacturing a zoom lens having, in order from an object: a first lens group having positive refractive power; a second lens group having negative refractive power; a third lens group having positive refractive power; and a fourth lens group having positive refractive power,
 the method comprising disposing each lens in a lens barrel so that   upon zooming from a wide-angle end state to a telephoto end state, a distance between the first lens group and the second lens group changes, a distance between the second lens group and the third lens group changes, a distance between the third lens group and the fourth lens group changes, and at least the first lens group moves, and   the following conditional expressions are satisfied:
   0.1&lt; fG 1/ fG 4&lt;1.0 
   10.0&lt; ft/dG 1&lt;16.0 
   where fG 1  denotes a focal length of the first lens group, fG 4  denotes a focal length of the fourth lens group, ft denotes a focal length of the zoom lens in the telephoto end state, and dG 1  denotes a thickness of the first lens group on the optical axis.   
     
     
         80 . A method for manufacturing a zoom lens having, in order from an object: a first lens group having positive refractive power; a second lens group having negative refractive power; a third lens group having positive refractive power; and a fourth lens group having positive refractive power,
 the method comprising disposing each lens in a lens barrel so that   upon zooming from a wide-angle end state to a telephoto end state, a distance between the first lens group and the second lens group changes, a distance between the second lens group and the third lens group changes, and a distance between the third lens group and the fourth lens group changes,   the first lens group is constituted by, in order from the object, a lens having negative refractive power and a lens having positive refractive power,   the second lens group is constituted by, in order from the object, a lens having negative refractive power, a lens having negative refractive power, and a lens having positive refractive power, and   the following conditional expressions are satisfied:
   0.050&lt;Σ D 2/ ft&lt; 0.115
 
   4.3&lt; f 4/ fw&lt; 6.8 
   where ΣD 2  denotes a distance on the optical axis from a lens surface closest to the object to a lens surface closest to an image in the second lens group, ft denotes a focal length of the zoom lens in the telephoto end state, fw denotes a focal length of the zoom lens in the wide-angle end state, and f 4  denotes a focal length of the fourth lens group.   
     
     
         81 . A method for manufacturing a zoom lens having, in order from an object: a first lens group having positive refractive power; a second lens group having negative refractive power; a third lens group having positive refractive power; and a fourth lens group having positive refractive power,
 the method comprising disposing each lens in a lens barrel so that   upon zooming from a wide-angle end state to a telephoto end state, a distance between the first lens group and the second lens group changes, a distance between the second lens group and the third lens group changes, and a distance between the third lens group and the fourth lens group changes,   the first lens group is constituted by, in order from the object, a lens having negative refractive power, and a lens having positive refractive power, and   the following conditional expressions are satisfied:
   −0.25&lt; M 2/ fw&lt; 1.10
 
   3.0&lt; fL 2/ fw&lt; 4.5 
   where M 2  denotes a moving distance of the second lens group upon zooming from the wide-angle end state to the telephoto end state (where a direction toward an image plane is positive), fw denotes a focal length of the zoom lens in the wide-angle end state, and fL 2  denotes a focal length of the lens having positive refractive power included in the first lens group.   
     
     
         82 . A method for manufacturing a zoom lens having, in order from an object: a first lens group having positive refractive power; a second lens group having negative refractive power; a third lens group having positive refractive power; and a fourth lens group having positive refractive power,
 the method comprising disposing each lens in a lens barrel so that   upon zooming from a wide-angle end state to a telephoto end state, a distance between the first lens group and the second lens group changes, a distance between the second lens group and the third lens group changes, a distance between the third lens group and the fourth lens group changes, and at least the first lens group moves,   the first lens group is constituted by a negative lens and a positive lens,   the second lens group is constituted by, in order from the object, a negative lens, a negative lens and a positive lens,   the third lens group is constituted by a positive lens and a negative lens, and   the following conditional expressions are satisfied:
   −1.50&lt;( G 2 R 2+ G 2 R 1)/( G 2 R 2− G 2 R 1)&lt;−0.10
 
   −2.00&lt;( G 3 R 2+ G 3 R 1)/( G 3 R 2− G 3 R 1)&lt;−0.50
 
   where G 2 R 1  denotes a radius of curvature of an object side lens surface of the negative lens disposed on an image side of the second lens group, G 2 R 2  denotes a radius of curvature of an image side lens surface of the negative lens disposed on the image side of the second lens group, G 3 R 1  denotes a radius of curvature of an object side lens surface of the negative lens of the third lens group, and G 3 R 2  denotes a radius of curvature of an image side lens surface of the negative lens of the third lens group.
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