Microscope tube lens, microscope apparatus and image pickup optical system
AssigneeOlympus Corporation
InventorYo FURUYA
Life of this patent
Estimating the term…
Abstract
A tube lens for a microscope includes, in the order from an object, a first lens group that has positive power and that includes a cemented lens, a second lens group that has negative power, and a third lens group has positive power. The tube lens satisfies the following condition expressions, where NA is a numerical aperture on an image side of the tube lens, FN is a field number of the tube lens, and ε is an airy disk diameter with respect to d line of the tube lens (588 nm): 0.04<NA; and 1700≦FN/ε.
Claims18
A tube lens that is for a microscope and that forms an enlarged image of an object by being combined with an infinity-corrected objective, the tube lens comprising in an order from an object side:
- a first lens group that has positive power and that includes a cemented lens;
- a second lens group that has negative power;
- and
- a third lens group that consists of a plurality of lenses each having positive power and that has positive power as a whole, wherein
- a following condition expression is satisfied, where FL is a focal length of the tube lens and D2 is a distance from a lens surface that is closest to the object in the tube lens to a position of an entrance pupil of the tube lens:
- 0.3<D2/FL<1.3.
An image pickup optical system comprising:
- an infinity-corrected objective;
- and
- a microscope tube lens, wherein
- the microscope tube lens includes in an order from an object side:
- a first lens group that has positive power and that includes a cemented lens;
- a second lens group that has negative power;
- and
- a third lens group that consists of a plurality of lenses each having positive power and that has positive power as a whole, and
- a following condition expression is satisfied, where FL is a focal length of the tube lens and D2 is a distance from a lens surface that is closest to an object in the tube lens to a position of an entrance pupil of the tube lens:
- 0.3<D2/FL<1.3.
A microscope tube lens that forms an enlarged image of an object by being combined with an infinity-corrected objective, the tube lens comprising in an order from an object side:
- a first lens group that has positive power and that includes a cemented lens;
- a second lens group that has negative power;
- and
- a third lens group that has positive power, wherein
- a following condition expression is satisfied, where NA is a numerical aperture on an image side of the tube lens, FN is a field number of the tube lens, and ε is an airy disk diameter with respect to d line (588 nm) of the tube lens:
- 0.04<NA;
- and
- 1700≦FN/ε.
Dependencies are inferred from the claim text.