Objective lens for endoscope
AssigneeOlympus Medical Systems Corp.
InventorTsutomu Sasamoto
Life of this patent
Estimating the term…
Abstract
An objective lens for an endoscope includes, in order from an object side, a front lens group having negative refractive power as a whole, a brightness aperture stop, and a rear lens group having positive refractive power as a whole. The front lens group includes, in order from the object side, a first lens group having negative refractive power and that may include only a single lens; and a second lens group that may include only a single lens, with the second lens group having a lens surface closest to the image side that is of a concave form directed toward the image side, the second lens group having positive refractive power as a whole; and the following condition (1) is satisfied: |f0/f1|≦1.1 (1) where f0 is the composite focal length of the front lens group, and f1 is the focal length of the first lens group.
Claims4
An objective lens for an endoscope comprising, in order from an object side:
- a front lens group having negative refractive power as a whole;
- a brightness aperture stop;
- and
- a rear lens group having positive refractive power as a whole;
- wherein
- said front lens group comprises, in order from the object side,
- a first lens group having negative refractive power that may include only a single lens;
- and
- a second lens group that may include only a single lens, said second lens group having a lens surface closest to the image side that is of a concave form directed toward the image side, said second lens group having positive refractive power as a whole;
- and the following condition (1) is satisfied:
- |f0/f1|<1.1 (1)
- where
- f0 is the composite focal length of said front lens group, and
- f1 is the focal length of said first lens group;
- and
- wherein there is an air space between said first lens group and said second lens group.
An objective lens for an endoscope comprising, in order from an object side:
- a front lens group having negative refractive power as a whole;
- a brightness aperture stop;
- and
- a rear lens group having positive refractive power as a whole;
- wherein
- said front lens group comprises, in order from the object side,
- a first lens group having negative refractive power that may include only a single lens;
- and
- a second lens group having positive refractive power as a whole that may include only a single lens;
- and the following condition (1) is satisfied:
- |f0/f1<1.1 (1)
- where
- f0 is the composite focal length of said front lens group, and
- f1 is the focal length of said first lens group;
- and
- wherein there is an air space between said first lens group and said second lens group.
Dependencies are inferred from the claim text.