Inverted equal-magnification relay lens and camera system

Patent metadata

Field	Value
Publication number	US-10281693-B2
Application number	US-201515303787-A
Country	US
Kind code	B2
Filing date	May 8, 2015
Priority date	May 9, 2014
Publication date	May 7, 2019
Grant date	May 7, 2019

Abstract

An inverted equal-magnification relay lens includes, in order from an object side: a first lens group having a positive power, and disposed near an object; a second lens group having a positive power, and disposed at a predetermined distance from the first lens group; and a third lens group having a negative power; wherein an entrance pupil position is more toward an object surface side than the first lens group, an exit pupil position is more toward a third lens group side than an image surface, and the following Formulas (1) and (2) are satisfied: 0.65≤|G1F/G2F|≤2.0 . . . (1); 0.35≤|G3F/G2F|≤3.1 . . . (2); where: G1F: a focal length of the first lens group; G2F: a focal length of the second lens group; and G3F: a focal length of the third lens group.

First claim

The invention claimed is:

1. An inverted equal-magnification relay lens comprising, in order from an object side:
a first lens group having a positive power, and disposed near an object;
a second lens group having a positive power, and disposed at a predetermined distance from the first lens group; and
a third lens group having a negative power,
wherein an entrance pupil position is more toward an object surface side than the first lens group, an exit pupil position is more toward a third lens group side than an image surface, and the following Formulas (1), (2), and (3) are satisfied:
0.65≤| G 1 F/G 2 F |≤2.0  (1)

0.35≤| G 3 F/G 2 F |≤3.1  (2)

1.7≤| E G1-G2 /E G2-G3 |≤6.2  (3)

where:
G 1 F: a focal length of the first lens group;
G 2 F: a focal length of the second lens group;
G 3 F: a focal length of the third lens group;
E G1-G2 is a distance between an image side principal point of the first lens group and an object side principal point of the second lens group; and
E G2-G3 is the distance between an image side principal point of the second lens group and an object side principal point of the third lens group.

2. The inverted equal-magnification relay lens according to claim 1 , wherein focusing is performed by shifting one of lenses comprised in the second lens group.

3. The inverted equal-magnification relay lens according to claim 1 , wherein:
the second lens group comprises, in order from the object side
a first cemented meniscus lens that presents its concave surface toward the image side and that comprises a positive lens and a negative lens, and
a single concave meniscus lens or a second cemented meniscus lens comprising a negative lens and a positive lens, opposing the first cemented meniscus lens with an aperture stop being sandwiched between them, and presenting its concave surface toward the object side;

the third lens group comprises a biconcave lens;
an object side NA is less than or equal to 0.125; and
a following Formula (5) is satisfied:
| Y/G 3 F |≥0.12  (5)

where:
Y (>0): a maximum image height; and
G 3 F: a focal length of the third lens group.

4. The inverted equal-magnification relay lens according to claim 1 , wherein the following Formula (6) is satisfied:
0.9≤ENT.P/EXT.P ≤1.1  (6)

where:
ENT.P: a distance from an object surface to an entrance pupil plane at a maximum image height; and
EXT.P: a distance from an exit pupil plane to an image surface at a maximum image height.

5. The inverted equal-magnification relay lens according to claim 1 , wherein:
a lens surface in the first lens group most toward the object side is a plane or a convex surface with respect to the object; and
following Formulas (7) and (8) are satisfied:
WD ≥50·λ/NA 2   (7)

D/Y ≥1.8  (8)

where:
WD: a distance from an object surface to the lens surface of the first lens group most toward the object side;
λ: a main wavelength used;
NA: an object side numerical aperture;
D: a distance from the lens surface of the third lens group most toward the image surface side to the image surface; and
Y (>0): a maximum image height.

6. The inverted equal-magnification lens according to claim 1 , wherein:
the second lens group comprises
a first cemented meniscus lens that presents its concave surface toward the image side and that comprises a positive lens and a negative lens, and
a single concave meniscus lens or a second cemented meniscus lens comprising a negative lens and a positive lens, opposing the first cemented meniscus lens with an aperture stop being sandwiched between them, and presenting its concave surface toward the object side;

the third lens group comprises a biconcave lens; and
the following Condition (9) is satisfied:

[

Equation
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⁢
1

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0.55
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Y
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∑

i
=
1

4

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{

1

R
i

⁢

(

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n
i

-

1

n

i
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Condition
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where:
Y (>0): a maximum image height the suffix i=1: a concave surface of the first cemented meniscus lens toward the image side;
the suffix i=2: a concave surface of the second cemented meniscus lens or the single concave meniscus lens toward the object side;
the suffix i=3: a concave surface of the biconcave lens of the third lens group toward the object side;
the suffix i=4: a concave surface of the biconcave lens of the third lens group toward the image side;
R i : a radius of curvature of a lens surface corresponding to the suffix i;
n i−1 : a refractive index of medium on the object side with respect to the lens surface corresponding to the suffix i; and
n i : a refractive index of medium on the image side with respect to the lens surface corresponding to the suffix i.

7. The inverted equal-magnification relay lens according to claim 1 , wherein:
the second lens group comprises
a first cemented meniscus lens that presents its c

Assignees

• Nikon Corp

Inventors

• Yamahiro Tomohiko

Classifications

• H04N23/957

  Light-field or plenoptic cameras or camera modules · CPC title

• H04N23/60

  Control of cameras or camera modules · CPC title

• G02B13/26

  for reproducing with unit magnification · CPC title

• H04N5/23212

  Electricity · mapped topic

• G02B13/0095 Primary

  Relay lenses or rod lenses (in instruments for viewing the inside of hollow bodies G02B23/2446) · CPC title