Back to results
US 9,753,271 B2Granted
Eyepiece lens, viewfinder optical system and optical apparatus equipped with the same, and method for manufacturing eyepiece lens
AssigneeNikon Corporation
InventorsIssei Tanaka, Hiroki Harada, Taku Matsuo
Life of this patent
Estimating the term…
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 (101g) formed by a wet process.
Claims22
An eyepiece lens comprising, in order from an object along an optical axis,
- 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
- an antireflection coating is disposed on at least one optical surface of the eyepiece lens, and
- 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 all lenses having negative refractive power in the first and third lens groups.
2 more elements
A method for manufacturing an eyepiece lens comprising:
- constructing the eyepiece lens to include, in order from an object along an optical axis, 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;
- disposing an antireflection coating, which includes at least one layer formed by a wet process, on at least one optical surface of the eyepiece lens;
- and
- disposing a lens having said one optical surface on which the antireflection coating is formed, in a lens barrel, and
- wherein the eyepiece lens is constructed such that 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 all lenses having negative refractive power in the first and third lens groups.
4 more elements
Dependencies are inferred from the claim text.