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US 11,143,849 B2Granted
Optical system, optical apparatus and method for manufacturing the optical system
AssigneeNikon Corporation
InventorsSatoshi Miwa, Hiroshi Yabumoto
Life of this patent
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Abstract
An optical system (OL) used for an optical apparatus such as a camera (1) includes a focusing group (Gf) that moves upon focusing, a diffractive optical element (GD) disposed on an object side of the focusing group (Gf) and a negative lens element (L1n) disposed on the object side of the diffractive optical element (GD). The optical system (OL) satisfies the following expressions 0.030<f/fpf<0.050 nd1n+0.006×νd1n<1.910 35<νd1n where, f: focal length of whole system in infinity focusing state fpf: focal length of diffractive optical element (GD) nd1n: refractive index of medium of negative lens element (L1n) on d-line νd1n: Abbe number of medium of negative lens element (L1n) on d-line.
Claims20
An optical system comprising:
- a focusing group that moves upon focusing;
- a diffractive optical element disposed on an object side of the focusing group;
- and
- a negative lens element disposed on the object side of the diffractive optical element, wherein
- the following expressions are satisfied:
- 0.030<f/fpf<0.050
- nd1n+0.006×νd1n<1.890
- 35<νd1n
- where,
- f:
- focal length of whole system in infinity focusing state
- fpf:
- focal length of the diffractive optical element
- nd1n:
- refractive index of medium of the negative lens element on d-line
- νd1n:
- Abbe number of medium of the negative lens element on d-line
- where, the lens element refers to each lens constituting a single lens or cemented lens.
15 more elements
An optical system comprising:
- a focusing group that moves upon focusing and has at least two lens elements;
- a diffractive optical element disposed on an object side of the focusing group;
- a vibration-isolating group disposed on an image side of the focusing group and configured to move so as to have a displacement component in a direction orthogonal to an optical axis;
- and
- at least three negative lens elements disposed on the image side of the vibration-isolating group,
- at least two of the three negative lens elements are specific negative lens elements that satisfy the following expressions:
- 0.654<θgF3n+0.00168×νd3n
- 1.98<nd3n+0.01×νd3n
- where,
- θgF3n:
- partial dispersion ratio of medium of the specific negative lens element
- νd3n:
- Abbe number of medium of the specific negative lens element on d-line
- nd3n:
- refractive index of medium of the specific negative lens element on d-line,
- the optical system further satisfying the following expression:
- TL/f<0.61
- where,
- TL:
- total length in infinity focusing state
- f:
- focal length of whole system in infinity focusing state
- where, the lens element refers to each lens constituting a single lens or cemented lens.
20 more elements
An optical system comprising:
- a focusing group that moves upon focusing;
- a diffractive optical element disposed on an object side of the focusing group;
- and
- a negative lens element disposed on the object side of the diffractive optical element, wherein
- all lenses disposed on the object side of the diffractive optical element are positive lens elements except the negative lens element, and
- the following expressions are satisfied:
- 0.030<f/fpf<0.050
- nd1n+0.006×νd1n<1.910
- 35<νd1n
- where,
- f:
- focal length of whole system in infinity focusing state
- fpf:
- focal length of the diffractive optical element
- nd1n:
- refractive index of medium of the negative lens element on d-line
- νd1n:
- Abbe number of medium of the negative lens element on d-line
- where, the lens element refers to each lens constituting a single lens or cemented lens.
16 more elements
An optical system comprising:
- a focusing group that moves upon focusing;
- a diffractive optical element disposed on an object side of the focusing group;
- and
- a negative lens element disposed on the object side of the diffractive optical element, wherein
- the following expressions are satisfied:
- 0.030<f/fpf<0.050
- nd1n+0.006×νd1n<1.910
- 35<νd1n
- θgF1n+0.00168×νd1n<0.643
- where,
- f:
- focal length of whole system in infinity focusing state
- fpf:
- focal length of the diffractive optical element
- nd1n:
- refractive index of medium of the negative lens element on d-line
- νd1n:
- Abbe number of medium of the negative lens element on d-line
- θgF1n:
- partial dispersion ratio of medium of the negative lens element
- where, the lens element refers to each lens constituting a single lens or cemented lens.
18 more elements
An optical system comprising:
- a focusing group that moves upon focusing;
- a diffractive optical element disposed on an object side of the focusing group;
- and
- a negative lens element disposed on the object side of the diffractive optical element, wherein
- the optical system comprises a first lens group having positive refractive power, a second lens group which is the focusing group, and a third lens group, which are disposed in order from an object,
- the first lens group comprises one positive lens element and one negative lens element, which are disposed on the image side of the diffractive optical element, and
- the following expressions are satisfied:
- 0.030<f/fpf<0.050
- nd1n+0.006×νd1n<1.910
- 35<νd1n
- where,
- f:
- focal length of whole system in infinity focusing state
- fpf:
- focal length of the diffractive optical element
- nd1n:
- refractive index of medium of the negative lens element on d-line
- νd1n:
- Abbe number of medium of the negative lens element on d-line
- where, the lens element refers to each lens constituting a single lens or cemented lens.
17 more elements
An optical system comprising:
- a focusing group that moves upon focusing;
- a diffractive optical element disposed on an object side of the focusing group;
- and
- a negative lens element disposed on the object side of the diffractive optical element, wherein
- the optical system comprises a first lens group having positive refractive power, a second lens group which is the focusing group, and a third lens group, which are disposed in order from an object, and
- the following expressions are satisfied:
- 0.030<f/fpf<0.050
- nd1n+0.006×νd1n<1.910
- 35<νd1n
- 0.001<f1/fpf<0.030
- where,
- f:
- focal length of whole system in infinity focusing state
- f1:
- focal length of the first lens group
- fpf:
- focal length of the diffractive optical element
- nd1n:
- refractive index of medium of the negative lens element on d-line
- νd1n:
- Abbe number of medium of the negative lens element on d-line
- where, the lens element refers to each lens constituting a single lens or cemented lens.
19 more elements
A method for manufacturing an optical system comprising a focusing group that moves upon focusing, and a diffractive optical element disposed on an object side of the focusing group,
- the method comprising one of the following features A, B, C, D, E and F, wherein
- the feature A comprising:
- disposing a negative lens element on the object side of the diffractive optical element;
- and
- disposing the lens groups and lens elements in a lens barrel so as to satisfy the following expressions:
- 0.030<f/fpf<0.050
- nd1n+0.006×νd1n<1.890
- 35<νd1n
- where,
- f:
- focal length of whole system in infinity focusing state
- fpf:
- focal length of the diffractive optical element
- nd1n:
- refractive index of medium of the negative lens element on d-line
- νd1n:
- Abbe number of medium of the negative lens element on d-line
- where, the lens element refers to each lens constituting a single lens or cemented lens,
- the feature B comprising:
- disposing the focusing group having at least two lens elements;
- disposing a vibration-isolating group on an image side of the focusing group and configured to move so as to have a displacement component in a direction orthogonal to an optical axis;
- disposing at least three negative lens elements on the image side of the vibration-isolating group;
- and
- disposing the lens groups and lens elements in a lens barrel so that at least two of the three negative lens elements being specific negative lens elements that satisfy the following expressions:
- 0.654<θgF3n+0.00168×νd3n
- 1.98<nd3n+0.01×νd3n
- where,
- θgF3n:
- partial dispersion ratio of medium of the specific negative lens element
- νd3n:
- Abbe number of medium of the specific negative lens element on d-line
- nd3n:
- refractive index of medium of the specific negative lens element on d-line;
- and
- the method further comprising disposing the lens groups and lens elements so as to satisfy the following expression:
- TL/f<0.61
- where,
- TL:
- total length in infinity focusing state
- f:
- focal length of whole system in infinity focusing state
- where, the lens element refers to each lens constituting a single lens or cemented lens,
- the feature C comprising:
- disposing a negative lens element on the object side of the diffractive optical element;
- arranging all lenses disposed on the object side of the diffractive optical element so as to be consisted of positive lens elements except the negative lens element;
- and
- disposing the lens groups and lens elements in a lens barrel so as to satisfy the following expressions:
- 0.030<f/fpf<0.050
- nd1n+0.006×νd1n<1.910
- 35<νd1n
- where,
- f:
- focal length of whole system in infinity focusing state
- fpf:
- focal length of the diffractive optical element
- nd1n:
- refractive index of medium of the negative lens element on d-line
- νd1n:
- Abbe number of medium of the negative lens element on d-line
- where, the lens element refers to each lens constituting a single lens or cemented lens,
- the feature D comprising:
- disposing a negative lens element on the object side of the diffractive optical element;
- and
- disposing the lens groups and lens elements in a lens barrel so as to satisfy the following expressions:
- 0.030<f/fpf<0.050
- nd1n+0.006×νd1n<1.910
- 35<νd1n
- θgF1n+0.00168×νd1n<0.643
- where,
- f:
- focal length of whole system in infinity focusing state
- fpf:
- focal length of the diffractive optical element
- nd1n:
- refractive index of medium of the negative lens element on d-line
- νd1n:
- Abbe number of medium of the negative lens element on d-line
- θgF1n:
- partial dispersion ratio of medium of the negative lens element
- νd1n:
- Abbe number of medium of the negative lens element on d-line
- where, the lens element refers to each lens constituting a single lens or cemented lens,
- the feature E comprising:
- disposing a negative lens element on the object side of the diffractive optical element;
- disposing a first lens group having positive refractive power, a second lens group which is the focusing group, and a third lens group, in order from an object;
- disposing the first lens group comprising one positive lens element and one negative lens element on the image side of the diffractive optical element;
- and
- disposing the lens groups and lens elements in a lens barrel so as to satisfy the following expressions:
- 0.030<f/fpf<0.050
- nd1n+0.006×νd1n<1.910
- 35<νd1n
- where,
- f:
- focal length of whole system in infinity focusing state
- fpf:
- focal length of the diffractive optical element
- nd1n:
- refractive index of medium of the negative lens element on d-line
- νd1n:
- Abbe number of medium of the negative lens element on d-line
- where, the lens element refers to each lens constituting a single lens or cemented lens,
- the feature F comprising:
- disposing a negative lens element on the object side of the diffractive optical element;
- disposing the optical system comprising a first lens group having positive refractive power, a second lens group which is the focusing group, and a third lens group, in order from an object;
- and
- disposing the lens groups and lens elements in a lens barrel so as to satisfy the following expressions:
- 0.030<f/fpf<0.050
- nd1n+0.006×νd1n<1.910
- 35<νd1n
- 0.001<f1/fpf<0.030
- where,
- f:
- focal length of whole system in infinity focusing state
- f1:
- focal length of the first lens group
- fpf:
- focal length of the diffractive optical element
- nd1n:
- refractive index of medium of the negative lens element on d-line
- νd1n:
- Abbe number of medium of the negative lens element on d-line
- where, the lens element refers to each lens constituting a single lens or cemented lens.
119 more elements
Dependencies are inferred from the claim text.