Objective lens system for endoscopes and image pickup system equipped with said objective lens system
First Claim
Patent Images
1. An objective lens system for endoscopes comprising:
- a front lens unit having negative refractive power,a rear lens unit having positive refractive power,said objective lens system having a long back focal length and satisfying the following condition (1);
space="preserve" listing-type="equation">|f.sub.1 /f|<
3.8 (1)wherein the reference symbol f, represents focal length of the front lens unit and the reference symbol f designates focal length of the objective lens system as a whole,in combination with an image pick-up system including;
an image sensor arranged obliquely or parallel relative to the optical axis of said objective lens system, andan optical path deflecting system arranged between said objective lens system and said image sensor,said image pickup system satisfying the following condition (7);
##EQU5## wherein the reference symbol I represents height of image, the reference symbol SK designates the distance from the final lens surface of the objective lens system to the image plane determined by the paraxial theory and the reference symbol EX denotes the distance from said final lens surface to the exit pupil.
1 Assignment
0 Petitions
Accused Products
Abstract
An image pickup system using an objective lens system for endoscopes consisting of an objective lens system comprising a front lens unit having negative refractive power and a rear lens unit having positive refractive power, and an optical system comprising an image sensor, and so adapted as to permit disposing the image sensor obliquely or parallel relatively to the optical axis by prolonging back focal length of said objective lens system and arranging an optical path deflecting system between said objective lens system and said image sensor.
-
Citations
56 Claims
-
1. An objective lens system for endoscopes comprising:
-
a front lens unit having negative refractive power, a rear lens unit having positive refractive power, said objective lens system having a long back focal length and satisfying the following condition (1);
space="preserve" listing-type="equation">|f.sub.1 /f|<
3.8 (1)wherein the reference symbol f, represents focal length of the front lens unit and the reference symbol f designates focal length of the objective lens system as a whole, in combination with an image pick-up system including; an image sensor arranged obliquely or parallel relative to the optical axis of said objective lens system, and an optical path deflecting system arranged between said objective lens system and said image sensor, said image pickup system satisfying the following condition (7);
##EQU5## wherein the reference symbol I represents height of image, the reference symbol SK designates the distance from the final lens surface of the objective lens system to the image plane determined by the paraxial theory and the reference symbol EX denotes the distance from said final lens surface to the exit pupil. - View Dependent Claims (2, 3, 4, 5, 6)
-
-
7. An objective lens system for endoscopes comprising:
-
a front lens unit having negative refractive power, a rear lens unit having positive refractive power, said objective lens system having a long back focal length and satisfying the following condition (1);
space="preserve" listing-type="equation">|f.sub.1 /f|<
3.8 (1)wherein the reference symbol f1 represents focal length of the front lens unit and the reference symbol f designates focal length of the objective lens system as a whole, and satisfying the following condition (11);
space="preserve" listing-type="equation">|h.sub.1 φ
.sub.1 |>
1.15|h.sub.4 φ
.sub.4 | (11)wherein the reference symbol h1 represents average height of the principal ray at the lens component arranged on the extreme object side, the reference symbol h4 designates average height of the principal ray at the lens component arranged on the extreme image side, the reference symbol φ
1 denotes power of the component arranged on the extreme image side and the reference symbol φ
4 represents power of the lens component arranged on the extreme image side. - View Dependent Claims (8)
-
-
9. An objective lens system for endoscope comprising:
-
a front lens unit having negative refractive power, and a rear lens unit having positive refractive power, said objective lens system having a long back focal length and satisfying the following condition (1);
space="preserve" listing-type="equation">|f.sub.1 /f<
3.8 (1)wherein the reference symbol f1 represents focal length of the front lens unit and the reference symbol f designates focal length of the objective lens system as a whole, and also satisfying condition (2); - View Dependent Claims (11, 14, 17)
-
-
10. 4<
- f2 /f<
30 (2)wherein the reference symbol f2 represents focal length of the rear lens unit, and wherein said rear lens unit has an aperture stop and a lens component having an aspherical surface on the object side including portions whose curvature is gradually enhanced as said portions are farther from the optical axis.
- f2 /f<
-
12. An objective lens system for endoscopes comprising:
-
a front lens unit having negative refractive power a rear lens unit having positive refractive power, said objective lens system having a long back focal length and satisfying the following conditions (1) and (2);
space="preserve" listing-type="equation">|f.sub.1 /f<
3.8 (1)wherein the reference symbol f1 represents focal length of the front lens unit and the reference symbol f designates focal length of the objective lens system as a whole, - View Dependent Claims (15, 18, 19, 22, 25)
-
-
13. 4<
- f2 /f<
30 (2)wherein the reference symbol f2 represents focal length of the rear lens unit, and wherein said objective lens system has an airspace at which the axial marginal ray becomes nearly parallel to the optical axis and an aperture stop disposed at a location before said airspace.
- f2 /f<
-
16. An objective lens system for endoscopes comprising:
-
a front lens unit having negative refractive power, and a rear lens unit having positive refractive power, said objective lens system having a long back focal length and satisfying the following condition (1);
space="preserve" listing-type="equation">1f.sub.1 |f|<
3.8 (1)wherein the reference symbol f1 represents focal length of the front lens unit and the reference symbol f designates focal length of the objective lens system as a whole, and also satisfying condition (2);
space="preserve" listing-type="equation">0.4<
f.sub.2 /f<
30 (2)wherein the reference symbol f2 represents focal length of the rear lens unit, and wherein said rear lens unit has an aperture stop therein and a lens component having an aspherical surface on the image side including portions whose curvature is gradually lowered as said portions are farther from the optical axis.
-
-
20. An objective lens system for endoscopes comprising:
-
a front lens unit having negative refractive power a rear lens unit having positive refractive power, said objective lens system having a long back focal length and satisfying the following condition (1);
space="preserve" listing-type="equation">|f.sub.1 /f|<
3.8 (1)wherein the reference symbol f1 represents focal length of the front lens unit and the reference symbol f designates focal length of the objective lens system as a whole, and satisfying the following conditions (2) and (5);
space="preserve" listing-type="equation">0.4<
f.sub.2 /f<
30 (2)wherein the reference symbol f2 represents focal length of the rear lens unit, and
space="preserve" listing-type="equation">|f.sub.B /f|>
1.4 (5)wherein the reference symbol fB represents back focal length of the objective lens system, and wherein said rear lens unit is equipped with an aperture stop arranged therein and comprises, at a location before said aperture stop, a cemented doublet having a convex surface on the image side, and a lens component selected from a single-element plano-convex lens component and a meniscus lens component, wherein said objective lens system has an airspace at which the axial marginal ray becomes nearly parallel to the optical axis, and comprises a front subsystem arranged at a location before said airspace and a rear subsystem arranged at a location after said airspace, and satisfies the following condition (15);
-
-
21. -1. 5<
- pA <
0 (15)wherein the reference symbol pA represents Petzval'"'"'s sum of said subsystem.
- pA <
-
23. An objective lens system for endoscopes comprising:
-
a front lens unit having negative refractive power, a rear lens unit having positive refractive power, said objective lens system having a long back focal length and satisfying the following condition (1);
space="preserve" listing-type="equation">|f.sub.1 /f|<
3.8 (1)wherein the reference symbol f1 represents focal length of the front lens unit and the reference symbol f designates focal length of the objective lens system as a whole,
-
-
24. 4<
- f2 /f<
30 (2)wherein the reference symbol f2 represents focal length of the rear lens unit, and wherein an aspherical surface is arranged in said front lens unit. - View Dependent Claims (30, 31, 32, 38, 39, 41, 42, 44, 45, 46, 48, 51, 52, 54, 56)
- f2 /f<
-
26. An objective lens system for endoscopes comprising:
-
a front lens unit having negative refractive power, a rear lens unit having positive refractive power, said objective lens system having a long back focal length and satisfying the following condition (1);
space="preserve" listing-type="equation">|f.sub.1 /f|<
3.8 (1)wherein the reference symbol f1 represents focal length of the front lens unit and the reference symbol f designates focal length of the objective lens system as a whole, wherein said rear lens unit comprises lens components having positive refractive powers respectively, and a lens component arranged on the extreme image side and having a concave surface kept in contact with air, said objective lens system satisfying the following condition (8);
space="preserve" listing-type="equation">|θ
.sub. |>
|θ
.sub. 2/3|(8)wherein the reference symbol θ
1 represents the angle formed between the offaxial principal ray emerging from the objective lens system and the optical axis, and the reference symbol θ
2 designates the angle formed between the offaxial principal ray and the offaxial ray having passed through the marginal portion of a stop.
-
-
27. An objective lens system for endoscopes comprising:
-
a front lens unit having negative refractive power, a rear lens unit having positive refractive power, said objective lens system having a long back focal length and satisfying the following condition (1);
space="preserve" listing-type="equation">|f.sub.1 /f<
3.8 (1)wherein the reference symbol f1 represents focal length of the front lens unit and the reference symbol f designates focal length of the objective lens system as a whole, and also satisfying the following condition (2); - View Dependent Claims (33, 34, 35, 36, 37, 40, 43, 47, 49, 50, 53, 55)
-
-
28. 4<
- f2 /f<
30 (2)wherein the reference symbol f2 represents focal length of the rear lens unit, wherein said rear lens unit comprises lens components having positive refractive powers respectively, and a lens component arranged on the extreme image side and having a concave surface kept in contact with air, said objective lens system satisfying the following condition (8);
space="preserve" listing-type="equation">|θ
.sub.1 |>
|θ
.sub.2 /3|(8)wherein the reference symbol θ
1 represents the angle formed between the offaxial principal ray emerging from the objective lens system and the optical axis, and the reference symbol θ
2 designates the angle formed between the offaxial principal ray and the offaxial ray having passed through the marginal portion of a stop.
- f2 /f<
-
29. An objective lens system for endoscopes comprising a front lens unit having negative refractive power and a rear lens unit having positive refractive power, said objective lens system having a long back focal length and satisfying the following conditions (1), (2) and (5):
-
space="preserve" listing-type="equation">|f.sub.1 /f|<
3.8 (1)
space="preserve" listing-type="equation">0.4<
f.sub.2 /f<
30 (2)
space="preserve" listing-type="equation">|f.sub.B /f|>
1.4 (5)wherein the reference symbol f represents focal length of the objective lens system as a whole, the reference symbol f1 designates focal length of the front lens unit, the reference symbol f2 denotes focal length of the rear lens unit and the reference symbol fB represents back focal length of the objective lens system.
-
Specification