Zoom optical system and image pickup apparatus using the same

Patent metadata

Field	Value
Publication number	US-10295802-B2
Application number	US-201715479626-A
Country	US
Kind code	B2
Filing date	Apr 5, 2017
Priority date	Apr 6, 2016
Publication date	May 21, 2019
Grant date	May 21, 2019

Abstract

A zoom optical system includes a plurality of lens units, the plurality of lens units consist of lens units having a positive refractive power and lens units having a negative refractive power, and the lens units having a positive refractive power include a positive lens unit and an image-side positive lens unit, the image-side positive lens unit is not moved, in the lens plurality of units, a space between the lens units disposed adjacently is changed at a time of zooming, at a time of focusing, or at a time of zooming and at a time of focusing, the positive lens unit includes a predetermined positive lens satisfying the following Conditional Expression (2), and the following Conditional Expression (1) is satisfied:

0.1≤ fGBUN 1/ fGPM ≤2.1  (1), and

60.8≤ν dGPMP 1≤100.0  (2).

First claim

What is claimed is:

1. A zoom optical system comprising:
a plurality of lens units; and
an aperture stop, wherein
the plurality of lens units consist of two or more lens units having a positive refractive power, and one or two or more lens units having a negative refractive power,
the two or more lens units having a positive refractive power include a positive lens unit having a positive refractive power, and an image-side positive lens unit,
the one or two or more lens units having a negative refractive power include an object-side negative lens unit,
the image-side positive lens unit is not moved along an optical axis at a time of zooming or at a time of focusing,
in the plurality of lens units, a space between the lens units disposed adjacently is changed at a time of zooming, at a time of focusing, or at a time of zooming and at a time of focusing,
the positive lens unit has the largest refractive power among the two or more lens units having a positive refractive power excluding the image-side positive lens unit,
the image-side positive lens unit is disposed closest to an image side among the two or more lens units having a positive refractive power,
when the plurality of lens units include two or more lens units having a negative refractive power, the object-side negative lens unit is disposed closest to an object side among the one or two or more lens units having a negative refractive power,
the object-side negative lens unit is moved such that a space between the object-side negative lens unit and the positive lens unit at a time of focusing to an object at infinity is narrower at a telephoto end than that at a wide angle end,
the aperture stop is disposed between a lens surface disposed closest to the image side in the object-side negative lens unit and a lens surface disposed closest to the image side in the positive lens unit, or adjacent to the lens surface disposed closest to the image side in the positive lens unit, and
the following Conditional Expressions (23), (17-2), and (30) are satisfied:
0.6≤ FNOw≤ 4.0  (23),

49.0°≤Ω Hw/ 2≤88.0°  (17-2), and

3.15 mm≤ Rimg≤ 40.0 mm  (30)

where
FNOw is an F-number at the wide angle end,
ΩHw is a total angle of view in a horizontal direction at the wide angle end, and
Rimg is a radius of an image circle at an image pickup element.

2. An image pickup apparatus comprising:
an optical system; and
an image pickup element having an image pickup surface and converting an image formed on the image pickup surface with the optical system into an electrical signal, wherein
the optical system is the zoom optical system as claimed in claim 1 .

3. A zoom optical system comprising:
a plurality of lens units; and
an aperture stop, wherein
the plurality of lens units consist of two or more lens units having a positive refractive power, and one or two or more lens units having a negative refractive power,
the two or more lens units having a positive refractive power include a positive lens unit having a positive refractive power, and an image-side positive lens unit,
the one or two or more lens units having a negative refractive power include an object-side negative lens unit,
the image-side positive lens unit is not moved along an optical axis at a time of zooming or at a time of focusing,
in the plurality of lens units, a space between the lens units disposed adjacently is changed at a time of zooming, at a time of focusing, or at a time of zooming and at a time of focusing,
the positive lens unit has the largest refractive power among the two or more lens units having a positive refractive power excluding the image-side positive lens unit,
the image-side positive lens unit is disposed closest to an image side among the two or more lens units having a positive refractive power,
when the plurality of lens units include two or more lens units having a negative refractive power, the object-side negative lens unit is disposed closest to an object side among the one or two or more lens units having a negative refractive power,
the object-side negative lens unit is moved such that a space between the object-side negative lens unit and the positive lens unit at a time of focusing to an object at infinity is narrower at a telephoto end than that at a wide angle end,
the aperture stop is disposed between a lens surface disposed closest to the image side in the object-side negative lens unit and a lens surface disposed closest to the image side in the positive lens unit, or adjacent to the lens surface disposed closest to the image side in the positive lens unit, and
the following Conditional Expressions (23-1), (25-1), (17-3), and (30) are satisfied:
0.6≤ FNOw≤ 3.9  (23-1),

0.0≤ ft/fw+ 13.38×tan(Ω Hw/ 2)−21.0≤350  (25-1),

35.5°≤Ω Hw/ 2≤88.0°  (17-3), and

3.15 mm≤ Rimg ≤40.0 mm  (30)

where
FNOw is an F-number at the wide angle end,
ft is a focal length of the zoom optical system at the telephoto end,
fw is a focal length of the zoom optical system at the wide angle end,
ΩHw is a total angle of view in a horizontal direction at the wide angle end, and
Rimg is a radius of an image circle at an image pickup element.

4. A zoom optical system comprising:
a plurality of lens units; and
an aperture stop, wherein
the lens units consist of two or more lens units having a positive refractive power, and one or two or more lens units having a negative refractive power,
the two or more lens units having a positive refractive power include a positive lens unit having a positive refractive power, and an image-side positive lens unit,
the one or two or more lens units having a negative refractive power include an object-side negative lens unit,
the image-side positive lens unit is not moved along an optical axis at a time of zooming or at a time of focusing,
in the lens units, a space between the lens units disposed adjacently is changed at a time of zooming, at a time of focusing, or at a time of zooming and at a time of focusing,
the positive lens unit has the largest refractive power among the two or more lens units having a positive refractive power excluding the image-side positive lens unit, and includes a predetermined positive lens satisfying the following Conditional Expression (2),
the image-side positive lens unit is disposed closest to the image side among the two or more lens units having a positive refractive power,
when the lens units include two or more lens units having a negative refractive power, the object-side negative lens unit is disposed closest to the object side among the one or two or more lens units having a negative refractive power,
the object-side negative lens unit is moved such that a space between the object-side negative lens unit and the positive lens unit at a time of focusing to an object at infinity is narrower at a telephoto end than that at a wide angle end,
the aperture stop is disposed between a lens surface disposed closest to the image side in the object-side negative lens unit and a lens surface disposed closest to the image side in the positive lens unit, or adjacent to the lens surface disposed closest to the image side in the positive lens unit,
the image-side positive lens unit includes a first sub-lens unit having a positive refractive power, and a second sub-lens unit including a positive lens and a negative lens, and
the following Conditional Expression (1) is satisfied:
0.1≤ fGBUN 1/ fGPM≤ 2.1  (1), and

60.8≤ν dGPMP 1≤100.0  (2)

where
fGBUN1 is a focal length of the first sub-lens unit,
fGPM is a focal length of the positive lens unit,
νdGPMP1 is an Abbe number of the predetermined positive lens,
the predetermined positive lens is a positive lens with the largest Abbe number among positive lenses of the positive lens unit, and
a lens component i

Assignees

• Olympus Corp

Inventors

• Kawamura Kazuteru

Classifications

• G02B13/18

  with lenses having one or more non-spherical faces, e.g. for reducing geometrical aberration {(G02B13/002 takes precedence)} · CPC title

• G02B15/20

  having an additional movable lens or lens group for varying the objective focal length · CPC title

• G02B9/34

  having four components only · CPC title

• G02B13/0045

  having five or more lenses · CPC title

• G02B3/14

  of variable focal length · CPC title