ENDOSCOPE FOR OBLIQUE VIEWING
First Claim
Patent Images
1. An endoscope for oblique viewing comprising:
- an image pickup device;
a front lens group having a positive refractive power;
a visual field direction converting element disposed on the image pickup device side of the front lens group; and
a rear lens group disposed on the image pickup device side of the visual field direction converting element and having a positive refractive power.
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0 Petitions
Accused Products
Abstract
An endoscope for oblique viewing including an image pickup device, a front lens group having a positive refractive power, a prism disposed on the CCD side of the front lens group, and a rear lens group disposed on the CCD side of the prism and having a positive refractive power.
132 Citations
19 Claims
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1. An endoscope for oblique viewing comprising:
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an image pickup device; a front lens group having a positive refractive power; a visual field direction converting element disposed on the image pickup device side of the front lens group; and a rear lens group disposed on the image pickup device side of the visual field direction converting element and having a positive refractive power. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. An endoscope for oblique viewing comprising:
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an image pickup device; a first lens unit frame in which a first lens unit having a front lens group having a positive refractive power is disposed; a second lens unit frame in which a second lens unit having a prism disposed on the image pickup device side of the front lens group and provided as a visual field direction converting element and a rear lens group disposed on the image pickup device side of the prism and having a positive refractive power is disposed; third lens unit frame in which a third lens unit having the image pickup device is disposed; and an illumination optical system disposed on the proximal end portion side of the endoscope for oblique viewing relative to the objective optical system, wherein if the lens distance between the front lens group and the rear lens group is d;
the focal length of the entire system is f;
the maximum image height is IH;
the lens distance from the first lens surface in the objective optical system to the object-side surface of the visual field direction changing element is D1;
the lens distance from the image-side surface of the visual field direction changing element to the image plane is D2;
the focal length of the front lens group is G1f;
the focal length of the rear lens group is G2f; and
the focal length of the entire objective optical system is f, 1.2<
d/f<
2.0;
1.5<
d/IH<
2.7;
1.6<
D1/f<
2.8;
2.3<
D2/f<
3.6;
0.4<
D1/D2<
1.0;
1.5<
G1f/f<
6.0;
3.0<
G2f/f<
6.0; and
0.3<
G1f/G2f<
2.0 are satisfied.
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Specification