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US 9,019,621 B2Granted
Objective optical system and observation apparatus provided with the same
AssigneeOlympus Corporation
InventorsKeisuke Takada, Keisuke Ichikawa
Life of this patent
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Abstract
An objective optical system of an embodiment according to the present invention is formed in such a way that: the objective optical system includes an immovable lens group which is arranged nearest to the object side, which is immovable in focusing, and which has negative power, and first and second movable lens groups at least one of which moves along the optical axis in focusing; and an amount of variation in magnification per movement of the first movable lens group is different from an amount of variation in magnification per movement of the second movable lens group.
Claims42
An objective optical system comprising:
- an immovable lens group arranged nearest to an object side, the immovable lens group being fixedly positioned in a focusing operation;
- and
- a first movable lens group and a second movable lens group, at least one of which moves along an optical axis in a focusing operation,
- wherein the immovable lens group has, at a position nearest to the object side, a lens component having a negative power,
- wherein an amount of variation in magnification per unit movement of the first movable lens group is different from an amount of variation in magnification per unit movement of the second movable lens group, and
- wherein the objective optical system is configured:
- to allow the first movable lens group to move alone along the optical axis while the second movable lens group is fixedly positioned;
- and to allow the second movable lens group to move alone along the optical axis while the first movable lens group is fixedly positioned.
5 more elements
An objective optical system with reversibly and continuously changeable observation state from a normal observation state to a close-up observation state achieved by movement of a predetermined lens group, comprising:
- an immovable lens group which is arranged nearest to an object side and having a negative power, the immovable lens group being fixedly positioned in a focusing operation and being fixedly positioned in an observation-state changing operation;
- and
- a first movable lens group and a second movable lens group, at least one of which moves along an optical axis in a focusing operation,
- wherein the first movable lens group is arranged nearer to the object side than the second movable lens group is arranged,
- wherein an amount of variation in magnification per unit movement of the first movable lens group is smaller than an amount of variation in magnification per unit movement of the second movable lens group,
- wherein an observation-state changing operation is made by movement of the second movable lens group, and
- wherein the objective optical system is configured:
- to allow, in an observation-state changing operation in a range from the normal observation state to the close-up observation state, the second movable lens group to move alone along the optical axis while the first movable lens group is fixedly positioned;
- and to allow, in a focusing operation, the first movable lens group to move alone along the optical axis while the second movable lens group is fixedly positioned.
6 more elements
An objective optical system which reversibly and continuously variable magnification from a normal observation state to a close-up observation state achieved by movement of a predetermined lens group, comprising:
- an immovable lens group arranged nearest to an object side, the immovable lens group being fixedly positioned in a magnification changing operation and being fixedly positioned in a focusing operation;
- a magnification-changing group which moves along an optical axis at least in a magnification-changing operation;
- and
- a focusing group which moves along the optical axis at least in a focusing operation,
- wherein a lens arranged nearest to the object side in the immovable lens group has a negative power,
- wherein the magnification-changing group is arranged nearer to the object side than the focusing group is arranged,
- wherein an amount of variation in magnification per unit movement of the magnification-changing group is larger than an amount of variation in magnification per unit movement of the focusing group,
- wherein a change in magnification is made by movement of the magnification-changing group, and
- wherein the objective optical system is configured:
- to allow, in a magnification changing operation in a range from the normal observation state to the close-up observation state, the magnification-changing group to move alone along the optical axis while the focusing group is fixedly positioned;
- and to allow, in a focusing operation, the focusing group to move alone along the optical axis while the magnification-changing group is fixedly positioned.
8 more elements
An objective optical system comprising:
- an immovable lens group arranged nearest to an object side, the immovable lens group being fixedly positioned in a focusing operation;
- and
- a first movable lens group and a second movable lens group, at least one of which moves along an optical axis in a focusing operation,
- wherein the immovable lens group has, at a position nearest to the object side, a lens component having a negative power,
- wherein an amount of variation in magnification per unit movement of the first movable lens group is different from an amount of variation in magnification per unit movement of the second movable lens group, and
- wherein the optical system further comprises a second immovable lens group arranged between the first movable lens group and the second movable lens group, the second immovable lens group being fixedly positioned in a focusing operation.
3 more elements
An objective optical system with reversibly and continuously changeable observation state from a normal observation state to a close-up observation state achieved by movement of a predetermined lens group, comprising:
- an immovable lens group arranged nearest to an object side and having a negative power, the immovable lens group being fixedly positioned in a focusing operation and being fixedly positioned in an observation-state changing operation;
- and
- a first movable lens group and a second movable lens group, at least one of which moves along an optical axis in a focusing operation,
- wherein the first movable lens group is arranged nearer to the object side than the second movable lens group is arranged,
- wherein an amount of variation in magnification per unit movement of the first movable lens group is smaller than an amount of variation in magnification per unit movement of the second movable lens group,
- wherein an observation-state changing operation is made by movement of the second movable lens group, and
- wherein the following condition is satisfied:
- 3<(mc-d/mu-d)/(mc-n/mc-d)<10
- where, mc-d denotes a transverse magnification of the objective optical system as a whole in a farthest point state in the close-up observation state, mu-d denotes a transverse magnification of the objective optical system as a whole in a farthest point state in the normal observation state, and mc-n denotes a transverse magnification of the objective optical system as a whole in a nearest point state in the close-up observation state.
6 more elements
An objective optical system with reversibly and continuously changeable observation state from a normal observation state to a close-up observation state achieved by movement of a predetermined lens group, comprising:
- an immovable lens group arranged nearest to an object side and having a negative power, the immovable lens group being fixedly positioned in a focusing operation and being fixedly positioned in an observation-state changing operation;
- and
- a first movable lens group and a second movable lens group, at least one of which moves along an optical axis in a focusing operation, wherein the first movable lens group is arranged nearer to the object side than the second movable lens group is arranged,
- wherein an amount of variation in magnification per unit movement of the first movable lens group is smaller than an amount of variation in magnification per unit movement of the second movable lens group,
- wherein an observation-state changing operation is made by movement of the second movable lens group, and
- wherein the objective optical system comprises a lens group that is located nearer to an image side than the first movable lens group is located, and the following condition is satisfied:
- 0.2<|(1−β1·β1)×β1′·β1∝|<3
- where, β1 denotes a transverse magnification of the first movable lens group and β1′ denotes a transverse magnification of the lens group that is located nearer to the image side than the first movable lens group is.
5 more elements
An objective optical system with reversibly and continuously changeable observation state from a normal observation state to a close-up observation state achieved by movement of a predetermined lens group, comprising:
- an immovable lens group arranged nearest to an object side and having a negative power, the immovable lens group being fixedly positioned in a focusing operation and being fixedly positioned in an observation-state changing operation;
- and
- a first movable lens group and a second movable lens group, at least one of which moves along an optical axis in a focusing operation,
- wherein the first movable lens group is arranged nearer to the object side than the second movable lens group is arranged,
- wherein an amount of variation in magnification per unit movement of the first movable lens group is smaller than an amount of variation in magnification per unit movement of the second movable lens group,
- wherein an observation-state changing operation is made by movement of the second movable lens group, and
- wherein the following condition is satisfied:
- DTu-d<−50
- where, DTu-d denotes a distortion of an image at an image height ratio of 1.0 in a farthest point state in the normal observation state.
6 more elements
An objective optical system with reversibly and continuously changeable observation state from a normal observation state to a close-up observation state achieved by movement of a predetermined lens group, comprising:
- an immovable lens group arranged nearest to an object side and having a negative power, the immovable lens group being fixedly positioned in a focusing operation and being fixedly positioned in an observation-state changing operation;
- and
- a first movable lens group and a second movable lens group, at least one of which moves along an optical axis in a focusing operation,
- wherein the first movable lens group is arranged nearer to the object side than the second movable lens group is arranged,
- wherein an amount of variation in magnification per unit movement of the first movable lens group is smaller than an amount of variation in magnification per unit movement of the second movable lens group,
- wherein an observation-state changing operation is made by movement of the second movable lens group, and
- wherein lenses included in the objective optical system are divided into five lens groups, of which a lens group arranged second nearest to the object side is the first movable lens group and a lens group arranged fourth nearest to the object side is the second movable lens group.
4 more elements
An objective optical system with reversibly and continuously variable magnification from a normal observation state to a close-up observation state achieved by movement of a predetermined lens group, comprising:
- an immovable lens group arranged nearest to an object side, the immovable lens group being fixedly positioned in a magnification changing operation and being fixedly positioned in a focusing operation;
- a magnification-changing group which moves along an optical axis at least in a magnification changing operation;
- and
- a focusing group which moves along the optical axis at least in a focusing operation,
- wherein a lens arranged nearest to the object side in the immovable lens group has a negative power,
- wherein the magnification-changing group is arranged nearer to the object side than the focusing group is arranged,
- wherein an amount of variation in magnification per unit movement of the magnification-changing group is larger than an amount of variation in magnification per unit movement of the focusing group,
- wherein a change in magnification is made by movement of the magnification-changing group, and
- wherein the following condition is satisfied:
- 3<(mc-d/mu-d)/(mc-n/mc-d)<11
- where, mc-d denotes a transverse magnification of the objective optical system as a whole in a farthest point state in the close-up observation state, mu-d denotes a transverse magnification of the objective optical system as a whole in a farthest point state in the normal observation state, and mc-n denotes a transverse magnification of the objective optical system as a whole in a nearest point state in the close-up observation state.
8 more elements
An objective optical system with reversibly and continuously variable magnification from a normal observation state to a close-up observation state achieved by movement of a predetermined lens group, comprising:
- an immovable lens group arranged nearest to an object side, the immovable lens group being fixedly positioned in a magnification changing operation and being fixedly positioned in a focusing operation;
- a magnification-changing group which moves along an optical axis at least in a magnification changing operation;
- and
- a focusing group which moves along the optical axis at least in a focusing operation,
- wherein a lens arranged nearest to the object side in the immovable lens group has a negative power,
- wherein the magnification-changing group is arranged nearer to the object side than the focusing group is arranged,
- wherein an amount of variation in magnification per unit movement of the magnification-changing group is larger than an amount of variation in magnification per unit movement of the focusing group,
- wherein a change in magnification is made by movement of the magnification-changing group, and
- wherein the following condition is satisfied:
- |γ|<11.5
- where, γ denotes an angle formed between an optical axis and a principal ray of light that is emergent from a lens nearest to an image side in the focusing group to form an image with an image height ratio of 1.0 in a nearest point state in the close-up observation state.
8 more elements
An objective optical system with reversibly and continuously variable magnification from a normal observation state to a close-up observation state achieved by movement of a predetermined lens group, comprising:
- an immovable lens group arranged nearest to an object side, the immovable lens group being fixedly positioned in a magnification changing operation and being fixedly positioned in a focusing operation;
- a magnification-changing group which moves along an optical axis at least in a magnification changing operation;
- and
- a focusing group which moves along the optical axis at least in a focusing operation,
- wherein a lens arranged nearest to the object side in the immovable lens group has a negative power,
- wherein the magnification-changing group is arranged nearer to the object side than the focusing group is arranged,
- wherein an amount of variation in magnification per unit movement of the magnification-changing group is larger than an amount of variation in magnification per unit movement of the focusing group,
- wherein a change in magnification is made by movement of the magnification-changing group, and
- wherein the following condition is satisfied:
- DT135<50
- where, DT135 denotes a distortion at an angle of view of 135 degrees.
8 more elements
Dependencies are inferred from the claim text.