Plurality of imaging optical systems and image pickup apparatus using the same

Patent metadata

Field	Value
Publication number	US-9557540-B2
Application number	US-201615092798-A
Country	US
Kind code	B2
Filing date	Apr 7, 2016
Priority date	Jan 14, 2015
Publication date	Jan 31, 2017
Grant date	Jan 31, 2017

Abstract

A plurality of imaging optical systems includes at least two imaging optical systems having different focal lengths. Each imaging optical system includes in order from an object side, a front lens unit having a positive refractive power, a diaphragm member, a focusing lens unit having a negative refractive power, and a rear lens unit. The front lens unit includes one of a positive lens and a negative lens as a common lens, and each of at least two imaging optical systems from among the plurality of imaging optical systems includes at least one common lens. At the time of focusing, only the focusing lens unit moves on an optical axis. Each imaging optical system satisfies the following conditional expression (1), and the plurality of imaging optical systems satisfy the following conditional expression (2).

0.06<| f fo /f |<0.4  (1)

1.02< f foLA /f foSM <2.50  (2).

First claim

What is claimed is:

1. A plurality of imaging optical systems comprising:
at least two imaging optical systems having different focal lengths, wherein
each imaging optical system in the plurality of imaging optical systems comprises in order from an object side,
a front lens unit having a positive refractive power,
a diaphragm member,
a focusing lens unit having a negative refractive power, and
a rear lens unit, and
the front lens unit includes one of a positive lens and a negative lens as a common lens, and
each of at least two imaging optical systems from among the plurality of imaging optical systems includes at least one common lens, and
at the time of focusing, only the focusing lens unit moves on an optical axis, and
each imaging optical system satisfies the following conditional expression (1), and
the plurality of imaging optical systems satisfies the following conditional expression (2):
0.06<| f fo /f|< 0.4  (1)

1.02< f foLA /f foSM <2.50  (2)

where,
f fo denotes a focal length of the focusing lens unit in each imaging optical system,
f denotes a focal length of an overall system of each imaging optical system at the time of infinite object point focusing,
f foLA denotes a maximum focal length from among focal lengths of the focusing lens units in the plurality of imaging optical systems, and
f foSM denotes a minimum focal length from among focal lengths of the focusing lens units in the plurality of imaging optical systems, and here,
the maximum focal length and the minimum focal length are to be obtained by comparing absolute values of the focal lengths.

2. A plurality of imaging optical systems comprising:
at least two imaging optical systems having different focal lengths, wherein
each imaging optical system in the plurality of imaging optical systems comprises in order from an object side,
a front lens unit having a positive refractive power,
a diaphragm member,
a focusing lens unit having a negative refractive power, and
a rear lens unit having a positive refractive power, and
the front lens unit includes one of a positive lens and a negative lens as a common lens, and
each of at least two imaging optical systems from among the plurality of imaging optical systems includes at least one common lens, and
at the time of focusing, only the focusing lens unit moves on an optical axis, and
the plurality of imaging optical systems satisfy the following conditional expressions (2) and (3):
1.02< f foLA /f foSM <2.50  (2)

1≦ K max /K min ≦1.60  (3)

where,
f foLA denotes a maximum focal length from among focal lengths of the focusing lens units in the plurality of imaging optical systems,
f foSM denotes a minimum focal length from among focal lengths of the focusing lens units in the plurality of imaging optical systems, and here,
the maximum focal length and the minimum focal length are to be obtained by comparing absolute values of the focal lengths,
K max denotes a maximum ratio from among ratios expressed by K,
K min denotes a minimum ratio from among ratios expressed by K,
here,
K (unit mm) is expressed by K=fb LD /MG fo ,
where,
fb LD is expressed by fb LD =f 2 /2000 mm,
where,
f denotes a focal length of an overall system of each imaging optical system at the time of infinite object point focusing, and
MG fo denotes a focusing sensitivity of each imaging optical system, where,
the focusing sensitivity is an amount of movement of an image plane with respect to a unit amount of movement of the focusing lens unit at the time of infinite object point focusing.

3. The plurality of imaging optical systems according to claim 1 , wherein each imaging optical system satisfies the following conditional expression (4):
0.5< f ff /f fb <1.8  (4)

where,
f ff denotes a focal length of the front lens unit in each imaging optical system, and
f fb denotes a focal length of the rear lens unit in each imaging optical system.

4. The plurality of imaging optical systems according to claim 2 , wherein each imaging optical system satisfies the following conditional expression (4):
0.5< f ff /f fb <1.8  (4)

where,
f ff denotes a focal length of the front lens unit in each imaging optical system, and
f fb denotes a focal length of the rear lens unit in each imaging optical system.

5. The plurality of imaging optical systems according to claim 2 , wherein each imaging optical system satisfies the following conditional expression (1):
0.06<| f fo /f|< 0.4  (1)

where,
f fo denotes a focal length of the focusing lens unit in each imaging optical system, and
f denotes the focal length of an overall system of each imaging optical system at the time of infinite object point focusing.

6. The plurality of imaging optical systems according to claim 1 , wherein the plurality of imaging optical systems satisfies the following conditional expression (3):
1≦ K max /K min ≦1.60  (3)

where,
K max denotes a maximum ratio from among ratios expressed by K,
K min denotes a minimum ratio from among ratios expressed by K,
here,
K (unit mm) is expressed by K=fb LD /MG fo ,
where,
fb LD is expressed by fb LD =f 2 /2000 mm,
where,
f denotes the focal length of an overall system of each imaging optical system at the time of infinite object point focusing, and
MG fo denotes a focusing sensitivity of each imaging optical system, where,
the focusing sensitivity is an amount of movement of an image plane with respect to a unit amount of movement of the focusing lens unit at the time of infinite object point focusing.

7. The plurality of imaging optical systems according to claim 1 , wherein each imaging optical system satisfies the following conditional expression (5):
1.0<Φ LD /Φ c <1.25  (5)

where,
Φ LD denotes a maximum effective aperture in the focusing lens unit in each imaging optical system, and
Φ c denotes a maximum diameter of an axial image forming light beam in the focusing lens unit in each imaging optical system.

8. The plurality of imaging optical systems according to claim 2 , wherein each imaging optical system satisfies the following conditional expression (5):
1.0<Φ LD /Φ c <1.25  (5)

where,
Φ LD denotes a maximum effective aperture in the focusing lens unit in each imaging optical system, and
Φ c denotes a maximum diameter of an axial image forming light beam in the focusing lens unit in each imaging optical system.

9. The plurality of imaging optical systems according to claim 1 , wherein the following conditional expression (6) is satisfied:
1≦ LDW max /LDW min ≦1.65  (6)

where,
LDW max denotes a maximum lens gross weight from among lens gross weights of the focusing lens units in the plurality of imaging optical systems, and
LDW min denotes a minimum lens gross weight from among lens gross weights of the focusing lens units in the plurality of imaging optical systems.

10. The plurality of imaging optical systems according to claim 2 , wherein the following conditional expression (6) is satisfied:
1≦ LDW max /LDW min ≦1.65  (6)

where,
LDW max denotes a maximum lens gross weight from among lens gross weights of the focusing lens units in the plurality of imaging optical systems, and
LDW min denotes a minimum lens gross weight from among lens gross weights of the focusing lens units in the plurality of imaging optical systems.

11. The plurality of imaging optical systems according to claim 1 , wherein each imaging optical system satisfies the following conditional expression (7):
−2< f fo /f fb <−0.27  (7)

where,
f fo denotes the focal length

Assignees

• Olympus Corp

Inventors

• Kawamura Kazuteru
• Iwasa Kazuyuki

Classifications

• H04N23/73

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• G03B11/045

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