Objective lens for variable viewing depth endoscope
First Claim
1. An objective lens for a variable viewing depth endoscope comprising, successively from an object side, a first lens group having positive refractive power and a second lens group which has positive refractive power and is movable along an optical axis;
- wherein near point focusing is made possible with the second lens group moved to the object side, and far point focusing is made possible with the second lens group moved to an image side; and
wherein the composite focal length fN of the whole system at near point viewing is set to be shorter than a composite focal length fF of the whole system at far point viewing.
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Accused Products
Abstract
A variable viewing depth endoscope comprises, successively from the object side, a first lens group G1 having positive refractive power and a second lens group G2 which has positive refractive power and is movable along the optical axis are arranged. Focusing at the near point side is made possible by moving the second lens group G2 to the object side, and focusing at a far point side is made possible by moving the second lens group G2 to an image side. The composite focal length fN during near point viewing is made shorter than a composite focal length fF of a whole system during far point viewing.
79 Citations
12 Claims
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1. An objective lens for a variable viewing depth endoscope comprising, successively from an object side, a first lens group having positive refractive power and a second lens group which has positive refractive power and is movable along an optical axis;
- wherein near point focusing is made possible with the second lens group moved to the object side, and far point focusing is made possible with the second lens group moved to an image side; and
wherein the composite focal length fN of the whole system at near point viewing is set to be shorter than a composite focal length fF of the whole system at far point viewing. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
- wherein near point focusing is made possible with the second lens group moved to the object side, and far point focusing is made possible with the second lens group moved to an image side; and
Specification