Endoscope objective lens system
First Claim
Patent Images
1. A fixed focal length endoscope objective lens system comprising a negative front lens group, a diaphragm, and a positive rear lens group, in this order from an object;
- wherein said negative front lens group comprises one lens element, or a plurality of non-cemented lens elements;
wherein the most object-side lens element of said negative front lens group is a negative lens element;
wherein said positive rear lens group comprises a plurality of non-cemented lens elements;
wherein at least one negative lens element is provided in said positive rear lens group;
wherein said endoscope objective lens system satisfies the following conditions;
−
1.45<
f1/f<
−
0.6
0.7<
|fF/fR|<
1.35
−
2.3<
f(−
)/f<
−
1.5whereinf1 designates the focal length of the most object-side negative lens element of said negative front lens group;
f designates the focal length of the entire endoscope objective lens system;
fF designates the focal length of said negative front lens group with (fF<
0);
fR designates the focal length of said positive rear lens group with (fR>
0); and
f(−
) designates the focal length of said negative lens element of said positive rear lens group.
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Abstract
An endoscope objective lens system includes a negative front lens group, a diaphragm, and a positive rear lens group, in this order from the object. The negative front lens group includes one lens element, or a plurality of non-cemented lens elements; and the most object-side lens element is constituted by a negative lens element. The positive rear lens group includes a plurality of non-cemented lens elements; and at least one negative lens element is provided in the positive rear lens group.
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Citations
8 Claims
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1. A fixed focal length endoscope objective lens system comprising a negative front lens group, a diaphragm, and a positive rear lens group, in this order from an object;
-
wherein said negative front lens group comprises one lens element, or a plurality of non-cemented lens elements; wherein the most object-side lens element of said negative front lens group is a negative lens element; wherein said positive rear lens group comprises a plurality of non-cemented lens elements; wherein at least one negative lens element is provided in said positive rear lens group; wherein said endoscope objective lens system satisfies the following conditions;
−
1.45<
f1/f<
−
0.6
0.7<
|fF/fR|<
1.35
−
2.3<
f(−
)/f<
−
1.5wherein f1 designates the focal length of the most object-side negative lens element of said negative front lens group; f designates the focal length of the entire endoscope objective lens system; fF designates the focal length of said negative front lens group with (fF<
0);fR designates the focal length of said positive rear lens group with (fR>
0); andf(−
) designates the focal length of said negative lens element of said positive rear lens group. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification