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US 2026/0227622 A1Published application
Eyepiece optical system, optical apparatus, and observation method
AssigneeNikon Corporation
InventorAyumu MAKIDA
Life of this patent
Estimating the term…
Abstract
An eyepiece optical system (EL) includes a first positive lens (Lp1) having a positive refractive power, and a second positive lens (Lp2) having a positive refractive power, and the following conditional expressions are satisfied, 1.7 < Np 1 < 2.05 , and 1.7 < Np 2 < 2.05 , where Np1: the refractive index of the first positive lens (Lp1) with respect to d-line, and Np2: the refractive index of the second positive lens (Lp2) with respect to d-line.
Claims21
An eyepiece optical system, comprising:
- a first positive lens that has positive refractive power;
- and a second positive lens that has positive refractive power, wherein the following conditional expressions are satisfied,
- 1.7
- <
- Np
-
- 1
- <
- 2.05
- ,
- and
- 1.7
- <
- Np
-
- 2
- <
- 2.05
- ,
- where Np1:
- a refractive index of the first positive lens with respect to d-line, and
- Np2:
- a refractive index of the second positive lens with respect to d-line.
20 more elements
An eyepiece optical system, comprising at least five lenses, wherein the following conditional expression is satisfied,
- 0.4
- <
- h
- /
- fe
- <
- 0.5
- ,
- where fe:
- a combined focal length of the eyepiece optical system, and
- h:
- a maximum object height of an object to be observed for the eyepiece optical system.
9 more elements
Dependencies are inferred from the claim text.