US2014307326A1PendingUtilityA1

Eyepiece lens, viewfinder optical system and optical apparatus equipped with the same, and method for manufacturing eyepiece lens

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Assignee: NIKON CORPPriority: Dec 28, 2011Filed: Jun 25, 2014Published: Oct 16, 2014
Est. expiryDec 28, 2031(~5.4 yrs left)· nominal 20-yr term from priority
Inventors:Issei TanakaHiroki HaradaTaku Matsuo
G03B 13/06G02B 1/115G02B 9/56G02B 27/0018G03B 13/08G02B 13/18G02B 1/11G02B 9/12G02B 23/14G02B 25/001
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Claims

Abstract

An eyepiece lens (EL) used for a viewfinder optical system (VF) for viewing, using the eyepiece lens (EL), an image formed by an objective lens (OL), an image displayed by a display member, or an object, wherein an antireflection coating ( 101 ) is disposed on at least one surface among the optical surfaces constituting the eyepiece lens (EL), and the antireflection coating ( 101 ) includes at least one layer ( 101 g ) formed by a wet process.

Claims

exact text as granted — not AI-modified
1 . An eyepiece lens used for a viewfinder optical system for viewing, using the eyepiece lens, an image formed by an objective lens, an image displayed by a display member, or an object,
 an antireflection coating being disposed on at least one surface among optical surfaces constituting the eyepiece lens, and   the antireflection coating including at least one layer formed by a wet process.   
     
     
         2 . The eyepiece lens according to  claim 1 , comprising, in order from an object,
 a first lens group having negative refractive power, a second lens group having positive refractive power, and a third lens group having negative refractive power.   
     
     
         3 . The eyepiece lens according to  claim 2 , wherein
 diopter adjustment can be performed by moving at least one of the first lens group, the second lens group and the third lens group along an optical axis.   
     
     
         4 . The eyepiece lens according to  claim 2 , wherein
 the second lens group includes a biconvex lens component.   
     
     
         5 . The eyepiece lens according to  claim 2 , wherein
 the third lens group includes a meniscus lens component having a convex surface facing the object.   
     
     
         6 . The eyepiece lens according to  claim 2 , wherein
 the following conditional expression is satisfied:
     Nn (ABE)>1.870 
   where Nn (ABE) denotes an average value of refractive indexes, with respect to d-line, of lenses having negative refractive power and included in the first lens group and the third lens group.   
     
     
         7 . The eyepiece lens according to  claim 2 , wherein
 the following conditional expression is satisfied:
   30.0>ν(ABE)
 
   where ν (ABE) denotes an average value of Abbe numbers, with respect to d-line, of lenses having negative refractive power and included in the first lens group and the third lens group.   
     
     
         8 . The eyepiece lens according to  claim 7 , wherein
 the following conditional expression is satisfied:
   ν2>40
 
   where ν2 denotes an average value of Abbe numbers, with respect to d-line, of lenses included in the second lens group.   
     
     
         9 . The eyepiece lens according to  claim 2 , wherein
 at least one optical surface of the second lens group is aspherical.   
     
     
         10 . The eyepiece lens according to  claim 2 , wherein
 the following conditional expression is satisfied:
     S 3>2.4 
   where S 3  denotes a shape factor of a lens component located closest to an eye point in the third lens group (that is, a value defined by (Ro 3 +Re 3 )/(Ro 3 −Re 3 ), where Ro 3  denotes a radius of curvature of the object side surface of the lens component located closest to the eye point in the third lens group, and Re 3  denotes a radius of curvature of the eye point side surface of the lens component located closest to the eye point in the third lens group).   
     
     
         11 . The eyepiece lens according to  claim 2 , wherein
 diopter adjustment can be performed by moving the second lens group along an optical axis.   
     
     
         12 . The eyepiece lens according to  claim 1 , wherein
 the antireflection coating is a multilayer film, and the layer formed by the wet process is an outermost surface layer among layers constituting the multilayer film.   
     
     
         13 . The eyepiece lens according to  claim 1 , wherein
 the following conditional expression is satisfied:
     nd≦ 1.30 
   where nd denotes a refractive index, with respect to d-line, of the layer formed by the wet process.   
     
     
         14 . The eyepiece lens according to  claim 1 , wherein
 the optical surface on which the antireflection coating is formed is a lens surface which is concave viewed from an eye point.   
     
     
         15 . The eyepiece lens according to  claim 1 , comprising, in order from an object, a first lens group having negative refractive power, a second lens group having positive refractive power, and a third lens group having negative refractive power, wherein
 the optical surface on which the antireflection coating is formed is a lens surface which is concave viewed from an eye point.   
     
     
         16 . The eyepiece lens according to  claim 15 , wherein
 the lens surface which is concave viewed from the eye point is a lens surface closest to the object among the optical surfaces of the first lens group to the third lens group.   
     
     
         17 . The eyepiece lens according to  claim 15 , wherein
 the lens surface which is concave viewed from the eye point is a lens surface closest to an image plane among the optical surfaces of the first lens group to the third lens group.   
     
     
         18 . The eyepiece lens according to  claim 1 , wherein
 the optical surface on which the antireflection coating is formed is a lens surface which is concave viewed from an object.   
     
     
         19 . The eyepiece lens according to  claim 1 , comprising, in order from an object, a first lens group having negative refractive power, a second lens group having positive refractive power, and a third lens group having negative refractive power, wherein
 the optical surface on which the antireflection coating is formed is a lens surface which is concave viewed from the object.   
     
     
         20 . The eyepiece lens according to  claim 19 , wherein
 the concave lens surface on which the antireflection coating is formed is a lens surface closest to an image plane among the optical surfaces of the second lens group.   
     
     
         21 . The eyepiece lens according to  claim 1 , wherein
 the optical surface on which the antireflection coating is formed is an optical surface other than the optical surface closest to an eye point.   
     
     
         22 . A viewfinder optical system for viewing an image formed by an objective lens, using an eyepiece lens,
 the eyepiece lens being the eyepiece lens according to  claim 1 .   
     
     
         23 . An optical apparatus, comprising
 a viewfinder optical system for viewing an image formed by an objective lens, using an eyepiece lens,   the viewfinder optical system being the viewfinder optical system according to  claim 22 .   
     
     
         24 . A method for manufacturing an eyepiece lens used for a viewfinder optical system for viewing, using the eyepiece lens, an image formed by an objective lens, an image displayed by a display member, or an object, the method comprising steps of:
 disposing an antireflection coating, which includes at least one layer formed by a wet process, on at least one surface among optical surfaces constituting the eyepiece lens; and   disposing the lens having the optical surface on which the antireflection coating is formed, in a lens barrel.   
     
     
         25 . The method for manufacturing an eyepiece lens according to  claim 24 , wherein
 the eyepiece lens includes, in order from an object, a first lens group having negative refractive power, a second lens group having positive refractive power, and a third lens group having negative refractive power.   
     
     
         26 . The method for manufacturing an eyepiece lens according to  claim 24 , wherein
 the following conditional expression is satisfied:
     nd≦ 1.30 
   where nd denotes a refractive index, with respect to d-line, of the layer formed by the wet process.   
     
     
         27 . The method for manufacturing an eyepiece lens according to  claim 24 , wherein
 the optical surface on which the antireflection coating is formed is a lens surface which is concave viewed from an eye point.

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