US2018113285A1PendingUtilityA1

Variable magnification optical system, optical device, and production method for variable magnification optical system

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Assignee: NIKON CORPPriority: Oct 30, 2012Filed: Dec 20, 2017Published: Apr 26, 2018
Est. expiryOct 30, 2032(~6.2 yrs left)· nominal 20-yr term from priority
Inventors:Tomoyuki SashimaAkihiko Obama
G02B 27/0025G02B 15/20G02B 15/173G02B 15/163G02B 13/18G02B 15/145129G02B 13/002
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Claims

Abstract

Composing, in order from an object side: a first lens group having positive refractive power; a second lens group having negative refractive power; a third lens group having positive refractive power; a fourth lens group having positive refractive power and a fifth lens group; 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, a distance between the second lens group and the third lens group, a distance between the third lens group and the fourth lens group and a distance between the fourth lens group and the fifth lens group being varied, and predetermined conditional expression being satisfied, thereby providing a small-size variable magnification optical system having a high zoom ratio and a high optical performance, an optical apparatus, and a method for manufacturing the variable magnification optical system.

Claims

exact text as granted — not AI-modified
1 - 13 . (canceled) 
     
     
         14 . A variable magnification optical system comprising, in order from an object side: a first lens group having positive refractive power; a second lens group having negative refractive power; a third lens group having positive refractive power; a fourth lens group having positive refractive power; and a fifth lens group;
 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, a distance between the second lens group and the third lens group, a distance between the third lens group and the fourth lens group and a distance between the fourth lens group and the fifth lens group being varied;   the following conditional expressions being satisfied:
   0.650<(− f 2)/ fw< 1.240
 
   −0.050<( d 3 t−d 3 w )/ fw< 0.750
 
   where fw denotes a focal length of the variable magnification optical system in the wide-angle end state, f2 denotes a focal length of the second lens group, d3w denotes a distance from a lens surface on a most image side of the third lens group to a lens surface on a most object side of the fourth lens group in the wide-angle end state, and d3t denotes a distance from the lens surface on the most image side of the third lens group to the lens surface on the most object side of the fourth lens group in the telephoto end state.   
     
     
         15 . An optical apparatus comprising a variable magnification optical system according to  claim 14 . 
     
     
         16 . A variable magnification optical system comprising, in order from an object side: a first lens group having positive refractive power; a second lens group having negative refractive power; a third lens group having positive refractive power; a fourth lens group having positive refractive power; and a fifth lens group;
 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, a distance between the second lens group and the third lens group, a distance between the third lens group and the fourth lens group and a distance between the fourth lens group and the fifth lens group being varied;   the following conditional expressions being satisfied:
   4.000<( TLt−TLw )/ fw< 7.000 
   −0.010<( d 3 t−d 3 w )/ ft< 0.130
 
   where fw denotes a focal length of the variable magnification optical system in the wide-angle end state, ft denotes a focal length of the variable magnification optical system in the telephoto end state, TLw denotes a distance from a lens surface on a most object side of the first lens group to an image plane in the wide-angle end state, TLt denotes a distance from the lens surface on the most object side of the first lens group to the image plane in the telephoto end state, d3w denotes a distance from a lens surface on a most image side of the third lens group to a lens surface on a most object side of the fourth lens group in the wide-angle end state, and d3t denotes a distance from the lens surface on the most image side of the third lens group to the lens surface on the most object side of the fourth lens group in the telephoto end state.   
     
     
         17 . A variable magnification optical system according to  claim 16 , wherein the following conditional expression is satisfied:
   0.300< f 1/ ft< 0.555   where ft denotes the focal length of the variable magnification optical system in the telephoto end state and f1 denotes a focal length of the first lens group.   
     
     
         18 . A variable magnification optical system according to  claim 16 , wherein the following conditional expression is satisfied:
   0.410< f 3/ f 4<1.000   where f3 denotes a focal length of the third lens group, and f4 denotes a focal length of the fourth lens group.   
     
     
         19 . An optical apparatus comprising a variable magnification optical system according to  claim 16 . 
     
     
         20 . A variable magnification optical system comprising, in order from an object side: a first lens group having positive refractive power; a second lens group having negative refractive power; an aperture stop; a third lens group having positive refractive power; a fourth lens group having positive refractive power; and a fifth lens group;
 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, a distance between the second lens group and the third lens group, a distance between the third lens group and the fourth lens group and a distance between the fourth lens group and the fifth lens group being varied, and a distance between the aperture stop and the fourth lens group being fixed.   
     
     
         21 . A variable magnification optical system according to  claim 20 , wherein the following conditional expression is satisfied:
   0.410< f 3/ f 4<1.000   where f3 denotes a focal length of the third lens group, and f4 denotes a focal length of the fourth lens group.   
     
     
         22 . A variable magnification optical system according to  claim 20 , wherein the following conditional expression is satisfied:
   −0.010<( d 3 t−d 3 w )/ ft< 0.130
   where ft denotes a whole system focal length of the variable magnification optical system in the telephoto end state, d3w denotes a distance on the optical axis from a lens surface on a most image side of the third lens group to a lens surface on a most object side of the fourth lens group in the wide-angle end state, and d3t denotes a distance on the optical axis from the lens surface on the most image side of the third lens group to the lens surface on the most object side of the fourth lens group in the telephoto end state.   
     
     
         23 . A variable magnification optical system according to  claim 20 , wherein the following conditional expression is satisfied:
   4.000<( TLt−TLw )/ fw< 7.000   where fw denotes a whole system focal length of the variable magnification optical system in the wide-angle end state, TLw denotes a distance on the optical axis from a lens surface on a most object side of the first lens group to an image plane in the wide-angle end state, and TLt denotes a distance on the optical axis from the lens surface on the most object side of the first lens group to the image plane in the telephoto end state.   
     
     
         24 . A variable magnification optical system according to  claim 20 , wherein the following conditional expression is satisfied:
   0.300< f 1/ ft< 0.555   where ft denotes a whole system focal length of the variable magnification optical system in the telephoto end state and f1 denotes a focal length of the first lens group.   
     
     
         25 . An optical apparatus comprising a variable magnification optical system according to  claim 20 . 
     
     
         26 . (canceled) 
     
     
         27 . A method for manufacturing a variable magnification optical system comprising, in order from an object side: a first lens group having positive refractive power; a second lens group having negative refractive power; a third lens group having positive refractive power; a fourth lens group having positive refractive power; and a fifth lens group; the method comprising the steps of:
 arranging the second lens group, the third lens group and the fourth lens group to satisfy the undermentioned conditional expressions; and   arranging, 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, a distance between the second lens group and the third lens group, a distance between the third lens group and the fourth lens group and a distance between the fourth lens group and the fifth lens group to be varied:
   0.650<(− f 2)/ fw< 1.240
 
   −0.050<( d 3 t−d 3 w )/ fw< 0.750
 
   where fw denotes a focal length of the variable magnification optical system in the wide-angle end state, f2 denotes a focal length of the second lens group, d3w denotes a distance from a lens surface on a most image side of the third lens group to a lens surface on a most object side of the fourth lens group in the wide-angle end state, and d3t denotes a distance from the lens surface on the most image side of the third lens group to the lens surface on the most object side of the fourth lens group in the telephoto end state.   
     
     
         28 . A method for manufacturing a variable magnification optical system comprising, in order from an object side: a first lens group having positive refractive power; a second lens group having negative refractive power; a third lens group having positive refractive power; a fourth lens group having positive refractive power; and a fifth lens group; the method comprising the steps of:
 arranging the first lens group, the second lens group, the third lens group, the fourth lens group and the fifth lens group to satisfy the undermentioned conditional expressions; and   arranging, 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, a distance between the second lens group and the third lens group, a distance between the third lens group and the fourth lens group and a distance between the fourth lens group and the fifth lens group to be varied:
   4.000<( TLt−TLw )/ fw< 7.000 
   −0.010<( d 3 t−d 3 w )/ ft< 0.130
 
   where fw denotes a focal length of the variable magnification optical system in the wide-angle end state, ft denotes a focal length of the variable magnification optical system in the telephoto end state, TLw denotes a distance from a lens surface on a most object side of the first lens group to an image plane in the wide-angle end state, TLt denotes a distance from the lens surface on the most object side of the first lens group to the image plane in the telephoto end state, d3w denotes a distance from a lens surface on a most image side of the third lens group to a lens surface on a most object side of the fourth lens group in the wide-angle end state, and d3t denotes a distance from the lens surface on the most image side of the third lens group to a lens surface on the most object side of the fourth lens group in the telephoto end state.   
     
     
         29 . A method for manufacturing a variable magnification optical system comprising, in order from an object side: a first lens group having positive refractive power; a second lens group having negative refractive power; an aperture stop; a third lens group having positive refractive power; a fourth lens group having positive refractive power; and a fifth lens group; the method comprising the steps of:
 arranging, 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, a distance between the second lens group and the third lens group, a distance between the third lens group and the fourth lens group and a distance between the fourth lens group and the fifth lens group to be varied, and a distance between the aperture stop and the fourth lens group to be fixed.

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