JPH09224903A - Hard endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hard endoscope which has a wide and bright view and superior flux distribution by specifying the values of an insertion part outer diameter and a visibility angle and setting the cross section area of a light guide in the insertion side to the value expressed by a specified equation. SOLUTION: A fiber tube 3 for storing a light guide 2 in an insertion part side is stored in the outermost outer tube 1, a system tube 4 for arranging a relay lens system R is arranged inside the fiber tube 3, and an objective tube 5 for storing an objective optical system O is provided in its inside. The outer diameter of the insertion part is set to more than 8mm and less than 12mm and the visibility angle is set to more than 90 deg. and less than 150 deg.. The cross section area S of the light guide 2 in the insertion part side is set to 3/sin<2> θ<=S2 <=14/sin<2> θ. The θ is set to 1/2 of the visibility angle. This constitution can provide a hard endoscope with wide, bright view and superior flux distribution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endoscope illumination and observation optical system, and more particularly to a rigid endoscope having a wide field of view using a relay lens for image transmission of the observation optical system. is there.

[0002]

2. Description of the Related Art In recent years, in the field of medical care, a television camera is attached to a rigid endoscope, and an image of the inside of a living body is displayed on a television monitor for diagnosis and treatment. Endoscopic surgery with a mirror has become popular.

The rigid endoscope system for displaying an image on the television monitor as described above has a configuration as shown in FIG. In this figure, 11 is a rigid endoscope,
Reference numeral 12 is an adapter, 13 is a television camera head, 14 is a camera control unit, 15 is a light source, and 16 is a monitor. In this system, the observation optical system of the rigid endoscope 11 is, for example, as shown in FIG.
The one described in No. 15 is known. This observation optical system includes an objective optical system O and relay lenses R ₁ , R ₂ ,
Be more configuration and R _3, the objective optical system O is negative lens group L
₁ and a positive lens unit L _2, and a meniscus lens unit L ₃ having a concave surface facing the object side. Further, since the rigid endoscope is used by being inserted into a body cavity or the like, it is necessary to sterilize it before use. Of these sterilization treatments, steam sterilization at high temperature and high pressure is effective, so that the optical member exposed on the outer surface of the rigid endoscope is made of a material that can withstand such sterilization treatment, for example, artificial sapphire mainly containing Al ₂ O _3. There are many things to configure.

On the other hand, when performing diagnosis or treatment using a rigid endoscope, it is necessary to observe the entire observation site to grasp the situation. Therefore, a rigid endoscope having a wide viewing angle is desired. Be done.

When an attempt is made to obtain such a wide-angle optical system, a negative lens closest to the object side, such as the objective optical system for a rigid endoscope described in JP-A-59-226315, is used. The radius of curvature becomes too small, which makes it difficult to manufacture a lens. Further, as shown in FIG. 38, in the objective optical system in which one negative lens is further added to the front group to widen the angle, the ray height of the first surface (the object side surface of the cover glass C) becomes higher as the angle becomes wider, The problem arises that the light beam is blocked and the observation field of view is blocked.

In order to prevent such a light beam from being eclipsed, the water vapor resistant cover glass C may be removed, but this is not preferable because the optical system is corroded during sterilization.

An optical system described in Japanese Unexamined Patent Publication No. 5-297272 is known as a conventional optical system that compensates for the drawbacks of such an optical system. As shown in FIG. 39, the objective optical system of this rigid endoscope has a negative lens L ₁ and a negative lens L ₂ each having a front lens group diverging system with a concave surface facing the image side, and a rear lens group focusing system. It is composed of two positive lens components. Further, the lens L ₁ is formed of a material having resistance to high temperature and high pressure steam sterilization, for example, Al ₂ O ₃ (artificial sapphire).

[0008]

SUMMARY OF THE INVENTION The present invention provides a rigid endoscope that has a wide field of view and is bright and has good light distribution.

[0009]

The rigid endoscope of the present invention comprises:
A light source side light guide for transmitting light from the light source,
An illumination system including an insertion section side light guide that receives light emitted from the light source side light guide and transmits the light, an insertion section including an observation optical system including an objective optical system and a relay lens, and the light source. A light collecting means arranged between the exit side surface of the side light guide and the entrance side surface of the insertion side light guide, and the insertion part outer diameter is 8 mm or more and 12 mm or less and the viewing angle 2θ is 90 ° or more and 150 ° or less. It is characterized in that the LG cross-sectional area S ₂ of the insertion portion side light guide satisfies the following condition (1).

(1) 3 / sin ² θ <≦ S ₂ ≦ 14 / sin ² θ The rigid endoscope of the present invention has a configuration as shown in FIGS. 1, 2 and 3, and FIG. Configuration, FIG. 2 is an enlarged cross-sectional view of the tip portion, and FIG. 3 is an enlarged end view of the tip portion (end view seen from the tip side). In these figures, the fiber tube 3 for accommodating the insertion side light guide 2 is housed in the outermost outer tube 1, and the fiber tube 3
A system tube 4 for arranging the relay lens system R is arranged inside of, and an objective tube 5 for accommodating the objective optical system O is arranged inside thereof.

There are two factors that determine the brightness of such a rigid endoscope. One of them is the brightness B _LG of the illumination optical system determined by the amount S _LG of the insertion side light guide 2, and the other factor is the brightness of the observation optical system proportional to the fourth power of the outer diameter Φ ₂ of the relay lens system. The brightness is B _Le .

The brightness B _Le of the observation optical system is proportional to the product of the square of NA of the relay lens system and the square of the image height I _Le . That is, the brightness B _Le of the observation optical system is proportional to the product of the square of NA of the relay lens system and the square of the image height I _Le . The NA of the relay lens system of the lens as shown in FIG. 4 is proportional to 1/2 of the [Phi _2/2 of the outer diameter of the relay lens system, an image height I _Le
Is proportional to 1/2 of the [Phi _2/2 of the outer diameter of the relay lens system.
Therefore, the brightness B _Le of the observation optical system is proportional to the fourth power of the outer diameter Φ ₂ of the relay lens system.

Now, let the outer diameter of the insertion portion of the rigid endoscope be Φ _1, and the outer peripheral portion of the endoscope and the metal space at the boundary portion between the light guide and the observation optical system occupy 25% of the cross-sectional area of the insertion portion. If it occupies, the brightness B _T of the rigid endoscope is as follows.

[0014] _{B T = B Le × B LG} (a) B Le αΦ 2 4 (b) B LG αS LG = π (Φ 1/2) 2 × 0.75-π (Φ 2/2) 2 (C) Brightness is maximized. Here, the outer diameter Φ ₁ of the insertion portion of the rigid endoscope and the amount of the light guide when the brightness is maximized S _LG
FIG. 5 is a graph showing the relationship of the above.

The rigid endoscope of the present invention has a structure as shown in FIG. 1, and has an observation optical system including an objective optical system O, a relay lens system R, and an eyepiece optical system E, and light from the light source side light guide 7. The light collecting means 9 for collecting light on the end face of the insertion side light guide 2 and the insertion side light guide 2 are provided, and illumination is possible by connecting the light source side light guide 7 connected to the light source 8. Become.

As an illumination optical system of an endoscope, an integral type that uses a long light guide to transmit and illuminate light from a light source, and a light guide that is divided into a light source side and an insertion side are provided. It is known that a two-body type in which this is coupled via an imaging lens system is used, but the rigid endoscope of the present invention adopts the latter type.

In general, a light guide having a relatively large NA has to have a high refractive index of the material, and since the material is colored, it is not suitable for transmitting illumination light over a long distance. Therefore, a light guide having a small coloring property and a relatively low refractive index and therefore a small NA is used as the light guide 7 on the light source side that must be long, and the light incident on the light guide 2 on the insertion portion side through the light converging means 9 is used. After being converted to have a large NA, the light guide 2 is made incident on the insertion portion side to be connected to obtain an effective illumination angle.

An illumination system used in a wide-field endoscope has to have a large light distribution angle 2θ, and therefore needs to have a large NA of light incident on the insertion-portion-side light guide 2, so that the light is condensed. The means 9 becomes a reduction system. FIG. 6 is a diagram showing the light distribution characteristic at the exit end face of the light source side light guide 7, and FIG. 7 is at the incident end face of the insertion section side light guide 2 after passing through the condensing means 9 in the ideal case. It is a figure which shows a light distribution characteristic.

Next, the conditions of the illumination optical system for obtaining the required light distribution angle 2θ will be described. In the present invention, as shown in FIG. 8, the end face of the light source side light guide 7 is placed at the front side focal position f _F of the light collecting means 9 and the end face of the insertion side light guide 2 is placed at the rear side focal position f _B. It is configured. Such an illumination optical system satisfies the following relationships (d) and (e).

[0020] _{Φ 4/2 = f × sin} θ 3 (d) Φ 3/2 = f × sin θ 4 (e) However, theta ₃ is the exit angle determined by the NA of the light source side light guide, theta ₄ insertion portion The half light distribution angle (light distribution angle 2θ ₄ ) determined by the NA of the side light guide, Φ ₃ is the outer diameter of the light source side light guide, and Φ ₄ is the outer diameter of the insertion portion side light guide.

By eliminating f from the above equations (d) and (e), the following relational equation (f) is obtained.

Φ ₄ = Φ ₃ × sin θ ₃ / sin θ ₄ (f) As can be seen from the above formula (f), the outer diameter Φ ₄ of the insertion side light guide is equal to the NA of the light source side light guide 2 and the outside. Determined from the relationship between the diameter Φ ₃ and the required light distribution angle. That is, as the viewing angle becomes wider, the light distribution angle needs to be wider, and the right side of the formula (f) becomes smaller, so that Φ ₄ can be made smaller. That is, the amount of the light guide on the insertion section side can be reduced.

Generally, a high-intensity xenon lamp is generally used as the light source of the illumination system of the endoscope. The size of the bright spot of this lamp is about several mm, and the divergence angle (light distribution angle) of the luminous flux at the bright spot position is about 60 ° to 80 ° according to the NA of the light guide on the light source side. . In addition, the diameter of the light guide on the light source side of the rigid endoscope with the diameter of the insertion part of about 8 mm to 12 mm is 4 mm to 6 mm for transmitting the light from the light source with high efficiency and reducing the weight from the viewpoint of operability. It is a degree. Further, since a light guide having a relatively small NA of about 0.5 to 0.7 is used for the characteristics of the light source and the light guide on the light source side, 60 ° to 80 ° from the light guide on the light source side
Light with a certain light distribution angle is emitted. Therefore, the light distribution angle is 90
If the outer diameter Φ ₄ of the light guide on the insertion section side is determined so that it is not less than 150 ° and not more than 150 °, when Φ ₄ is the smallest from the formula (f), NA of the light guide on the light source side is 0.5, and the light guide side is The outer diameter Φ ₃ of the light guide is 4 mm, and the largest Φ ₄ is when the light source side light guide NA is 0.7 and the light source side light guide outer diameter Φ _{3 is} 6 mm. That is, according to the formula (d), in order to maintain brightness and improve light distribution in a rigid endoscope with a viewing angle of 90 ° or more and 150 ° or less, the outer diameter Φ _{4 of the} light guide on the insertion side must satisfy the following conditions. Good.

2 / sin θ ≦ Φ ₄ ≦ 4.2 / sin θ where 2θ is a viewing angle.

Therefore, it is desirable that the cross-sectional area S ₂ of the light guide on the insertion section side should satisfy the above-mentioned condition (1).

When the field of view of the observation optical system is set to a wide angle, the cross-sectional area of the light guide for which the brightness of the rigid endoscope shown in the condition (1) is optimum becomes smaller than the cross-sectional area determined by the solid line in FIG. Therefore, if the field of view is widened, it will not be bright even if the cross-sectional area of the light guide for illumination is increased, so by increasing the outer diameter of the relay lens after securing the necessary cross-sectional area of the light guide. It needs to be bright.

If the lower limit of the condition (1) is exceeded, the brightness of the illumination optical system may be insufficient. If the upper limit of the condition (1) is exceeded, the light converging means cannot convert the light incident on the insertion-side light guide 2 so as to increase the NA, and an effective illumination angle cannot be obtained. Further, if the light converging means is used to convert the light incident on the insertion side light guide 2 so as to increase the NA, the space of the illumination optical system is taken up more than necessary, the space of the observation optical system is reduced, and the brightness of the observation optical system is reduced. Run short.

The following Tables 1 and 2 show the required outer diameter Φ ₄ of the insertion side light guide and the cross-sectional area S ₂ of the insertion side light guide for each viewing angle in the illumination optical system of the endoscope. . Further, Table 1 shows the case where the light source side light guide 7 having an outer diameter Φ ₃ = 4.5 mm has NA = 0.5 and 0.7.

Table 1 When light source side light guide 7 is NA = 0.5 Angle of view 90 ° 120 ° 150 ° NA 0.71 0.87 0.97 Φ ₄ 3.18 2.60 2.33 S ₂ 7.95 5.30 4.26 Table 2 Light source side light guide 7 is NA = At 0.7 Angle of view 90 ° 120 ° 150 ° NA 0.71 0.87 0.97 Φ ₄ 4.45 3.63 3.26 S ₂ 15.6 10.4 8.35 In Table 1 above, the NA column is required to achieve the required light distribution angle. The NA value of the light guide on the insertion section side is shown, and the outer diameter Φ ₄ and the cross-sectional area S _{2 of the} light guide on the insertion section side are determined according to the values.

According to Table 2, the cross-sectional area of the insertion-portion-side light guide should be within the range indicated by the broken line in FIG. 5 (the shaded portion) within the range of the angle of view of 90 ° to 150 °. I understand. In other words, when the field of view is widened, it does not become bright even if the cross-sectional area of the light guide for illumination is increased, and it can be made bright by increasing the outer diameter of the relay lesbian after securing the necessary cross-sectional area of the light guide.

Therefore, in order to obtain a brighter endoscope in the rigid endoscope of the present invention having the above structure, the cross-sectional area S ₄ of the relay lens system in the observation optical system satisfies the following condition (2). It is desirable to do.

(2) 0.35 (S ₁ −S ₂ ) ≦ S ₄ ≦ 0.8 (S ₁ −S ₂ ), where S ₁ is the cross-sectional area of the insertion portion of the rigid endoscope, and S ₂ is the insertion portion. It is a cross-sectional area of the side light guide.

The above condition (2) is a condition necessary for defining the brightness of the observation optical system necessary for obtaining a bright rigid endoscope.

The cross-sectional area S ₄ of the relay lens system contributes to the size of NA that determines the brightness of the optical system when one relay length is determined. The larger the cross-sectional area S ₄ of the relay lens system, the larger the NA becomes, and the brightness of the optical system becomes larger in proportion to the square of NA. Therefore, it is desirable to increase the cross-sectional area of the relay lens system.

If the lower limit of the condition (2) is exceeded, the brightness of the observation optical system may be insufficient. If the upper limit of the condition (2) is exceeded, the cross-sectional area of the insertion-portion-side light guide will be reduced, and the brightness in the illumination optical system may be insufficient.

Next, desirable conditions in the construction of the rigid endoscope of the present invention will be described.

The wide-field optical system has a higher light ray height on the first surface of the cover glass, which is arranged closest to the object side of the objective optical system than an optical system having a normal viewing angle. Therefore, condition (1)
In the wide-angle rigid endoscope satisfying the above condition, it is desirable that the cross-sectional area S ₃ of the cover glass placed on the most object side of the objective optical system satisfies the following condition (3).

(3) 0.35 (S ₁ −S ₂ ) ≦ S ₃ ≦ 0.8 (S ₁ −S ₂ ) This condition (3) is the first condition of the cover glass C in the wide-angle rigid endoscope. This is a condition that the ray cannot be blocked on the surface.

As shown in FIG. 3, the cross-sectional area S ₃ that the cover glass C can take depends on the outer diameter of the outer tube 1 and the cross-sectional area of the insertion side light guide 2. Since the cross-sectional area of the insertion side light guide 2 is determined by the viewing angle as described above, the possible cross-sectional area S ₃ of the cover glass C depends on the outer diameter of the outer tube 1 and the viewing angle.

The upper limit of the condition (3) defines the maximum size of the cover glass that can secure the brightness. When the value goes below the lower limit of the condition (3), the light beam may be eclipsed by the first surface and the observation visual field may be eclipsed. Further, when a cover glass satisfying the condition (3) is used, the cover glass can be formed of a plane parallel plate, and it is desirable that a light beam is not eclipsed by the first surface of the cover glass.

If a relay lens system satisfying the condition (2) and having a diameter larger than that of the conventional one is used, the size of the image becomes larger than that of the conventional one. In this case, it is desirable that the cover glass is a negative lens with the concave surface facing the image side, and the light ray height on the first surface of the cover glass is low.

When forming a negative lens on the cover glass, it is desirable that the following condition (4) is satisfied.

(4) 3 ≦ | r _a / r _b | ≦ 80 where r _a is the radius of curvature of the concave surface of the cover glass, and r _b is the most image of the negative lens group arranged on the object side of the objective optical system. It is the radius of curvature of the side surface.

The upper limit of condition (4) is the first of the cover glass.
The radius of curvature r _a to keep the rays from eclipsing at the surface,
It defines the ratio of the magnitudes of r _{b. If} the upper limit of 80 is exceeded, there is a risk that the light beam will be eclipsed. If the lower limit of 3 of the condition (4) is exceeded, the radius of curvature of the concave surface of the cover glass becomes too tight, making it difficult to adjust the one-sided blur and the like, which may cause a problem in assembly.

It is desirable that the object side surface of the cover glass is a flat surface or a surface close to a flat surface. This is because when the cover glass is formed of artificial sapphire or the like, it has a high hardness, so a special process is required for polishing, and polishing both surfaces is technically difficult and costly.

It is more desirable for the rigid endoscope of the present invention to satisfy the following condition (5).

(5) 0.5 ≦ | f _n /f|≦0.95 where f _n is the focal length of the negative lens group disposed on the object side of the objective optical system, and f is the entire objective optical system. Is the focal length of.

The condition (5) defines the ratio of the focal lengths of the negative lens group arranged on the object side of the objective optical system and the entire objective optical system. When the upper limit of the condition (5) is exceeded, the focal length of the negative lens group becomes long, and considering that the image height is constant, the focal lengths of the lens groups other than the negative lens group must be shortened for widening the angle of view. Therefore, the optical system is susceptible to aberration correction and decentering due to assembly. If the lower limit of the condition (5) is exceeded, the focal length of the negative lens group becomes too short, and the optical system is apt to be affected by aberration correction and decentering during assembly, which is not preferable.

In the rigid endoscope of the present invention, the cover glass placed on the most object side of the objective optical system is Al ₂ O ₃
It is made of (artificial sapphire).

Next, the structure of the illumination optical system of the rigid endoscope of the present invention will be described. The condensing means in the illumination optical system of the rigid endoscope of the present invention uses, as an example, two positive lenses as shown in FIG.

As shown in FIG. 8, the end surface of the light guide 4 on the light source side is placed at the front focal position f _F of the lens as the light converging means, and the end surface of the insertion side light guide 4 is placed at the rear focal position f _B. I have. At that time, as described above, equations (d) and (e
) Satisfies the relationship shown in.

[0052] _{Φ 4/2 = f × sin} θ 3 (d) Φ 3/2 = f × sin θ 4 (e) the formula (d), the satisfying the relationship shown in (e), requiring It is possible to obtain a sufficient wide-angle light distribution.

Similar effects can be obtained even if a conical optical fiber bundle as shown in FIG. 10 is used as the light collecting means used in the illumination optical system of the rigid endoscope of the present invention. At this time, in order to obtain the required wide-angle light distribution, when the end face a of the conical optical fiber bundle facing the light guide on the light source side is the incident end face, and the opposite end face b is the exit end face NA and the incident end face a It is desirable that the ratio of the diameter of the emission end face b and the ratio of the diameter of the emission end face b satisfy the following conditions (6) and (7), respectively.

(6) 0.6 ≦ NA ≦ 1 (7) 0.5 ≦ Φ _b / Φ _a ≦ 1 where Φ _a and Φ _b are the entrance end face diameter and the exit end face diameter of the conical optical fiber bundle, respectively. Is.

Unless the above conditions (6) and (7) are satisfied, bright and wide-angle illumination cannot be achieved, which is not preferable.

Further, in the rigid endoscope of the present invention, it is conceivable that the assembling image and the angle of view are decentered, and especially in the case of a wide-angle optical system, insufficient light distribution around the visual field may become a problem. In order to solve this problem, as shown in FIG. 36, the light distribution is improved by deflecting the tip of each optical fiber of the insertion section side light guide on the object side toward the visual field direction of the rigid endoscope. Can be done. The rigid endoscope of the present invention is used as a system in which a television camera having a built-in solid-state image sensor is attached to the rear of the relay lens system to display an endoscopic image on a television monitor so that the television image can be observed. be able to. In this case, an imaging lens for forming an image transmitted by the relay lens system of the rigid endoscope on the solid-state image sensor is provided in the television camera or an adapter for mounting the television camera on the rigid endoscope. It is provided. As this image forming lens, it is desirable to use a zoom lens system that satisfies the following conditions (8) and (9). _{(8) 1.5 ≦ M g ≦} 3 (9) 1.5 ≦ φI Tmax / I TV ≦ 3 However, M _g is the zoom ratio of the zoom lens system, .phi.I _Tmax most image increases on the solid-state imaging device The image size, I _TV, is the diagonal length of the solid-state image sensor. If the lower limit of 1.5 of the condition (8) is not satisfied, the effect of enlarging the image becomes insufficient, and if the upper limit of 3 is not satisfied, the brightness of the image may be insufficient. If the lower limit of 1.5 of the condition (9) is not satisfied, the image size is too small, and if the upper limit of 3 is not satisfied, the brightness of the image may be insufficient.

[0057]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of a rigid endoscope of the present invention will be described based on each embodiment.

FIG. 1 is a view showing the structure of the rigid endoscope of the present invention,
FIG. 2 is an enlarged cross-sectional view of the distal end portion of the rigid endoscope of the present invention, and FIG. 3 is an enlarged end view of the distal end surface of the rigid endoscope of the present invention.

As shown in FIG. 1, the structure of the rigid endoscope of the present invention includes an objective optical system O and a three-time relay (relay lens R ₁ ,
Relay lens system R consisting of R ₂ and R ₃ ) and eyepiece optical system E
And an illumination system including an insertion section side light guide 2, a light collecting means 9, a light source side light guide 7 and a light source 8.

The observation optical system of the first embodiment of the rigid endoscope of the present invention has the following data as shown in FIG. Example 1 F number = 5.075, object distance = 30, image height = 2.235, angle of view = 130 ° r ₁ = ∞ d ₁ = 0.4000 n ₁ = 1.76820 ν ₁ = 71.79 r ₂ = ∞ d ₂ = 0.2000 r ₃ = ∞ d ₃ = 0.5000 n ₂ = 1.88300 ν ₂ ＝ 40.78 r ₄ ＝ 1.4600 d ₄ ＝ 0.7500 r ₅ ＝ ∞ d ₅ ＝ 4.7997 n ₃ ＝ 1.80610 ν ₃ ＝ 40.95 r ₆ ＝ ∞ (aperture) d ₆ ＝ 5.2403 n ₄ = 1.80610 ν ₄ ＝ 40.95 r ₇ ＝ -5.2880 d ₇ ＝ 0.3000 r ₈ ＝ 8.4830 d ₈ ＝ 3.6500 n ₅ ＝ 1.60311 ν ₅ ＝ 60.68 r ₉ ＝ -3.4700 d ₉ ＝ 1.3500 n ₆ ＝ 1.84666 ν ₆ ＝ 23.78 r _{10 = -7.8000 d 10 = 3.0200 r} 11 = -3.7050 d 11 = 1.2000 n 7 = 1.76182 ν 7 = 26.52 r 12 = 14.0020 d 12 = 3.2000 n 8 = 1.77250 ν 8 = 49.60 r 13 = -5.3520 d 13 = 3.1100 r ₁₄ = ∞ _{(image) d 14 = 4.0000 r 15 =} 18.9290 d 15 = 43.7000 n 9 = 1.62004 ν 9 = 36.26 r 16 = ∞ d 16 = 2.5800 r 17 = 14.1270 d 17 = 1.0000 n 10 = 1.80610 ν 10 = 40.95 r ₁₈ = 6.4540 d _{18 3.0000 n 11 = 1.65160 ν 11 =} 58.52 r 19 = -25.2790 d 19 = 1.8000 r 20 = ∞ d 20 = 43.7000 n 12 = 1.62004 ν 12 = 36.26 r 21 = -18.9290 d 21 = 8.0000 r 22 = 18.9290 d 22 = 43.7000 n ₁₃ = 1.62004 ν ₁₃ = 36.26 r ₂₃ = ∞ d ₂₃ = 2.5800 r ₂₄ = 14.1270 d ₂₄ = 1.0000 n ₁₄ = 1.80610 ν ₁₄ ＝ 40.95 r ₂₅ ＝ 6.4540 d ₂₅ ＝ 3.0000 n ₁₅ = 1.65 160 ν ₁₅ = 58.52 r ₂₆ = -25.2790 d ₂₆ = 1.8000 r ₂₇ = ∞ d ₂₇ = 43.7000 n ₁₆ = 1.62004 ν ₁₆ = 36.26 r ₂₈ = -18.9290 d ₂₈ = 8.0000 r ₂₉ = 18.9290 d ₂₉ = 43.7000 n ₁₇ = 1.62004 ν ₁₇ = 36.26 r _{30 = ∞ d 30 = 2.5800 r} 31 = 14.1270 d 31 = 1.0000 n 18 = 1.80610 ν 18 = 40.95 r 32 = 6.4540 d 32 = 3.0000 n 19 = 1.65160 ν 19 = 58.52 r 33 = -25.2790 d 33 = 1.8000 r 34 _{= ∞ d 34 = 43.7000 n 20} = 1.62004 ν 20 = 36.26 r 35 = -16.5090 d 35 = 3.6100 r 36 = ∞ ( _{image) S 2 = 9.08, S 3} = 43.01, S 4 = 28.27, f _n /f|=0.668 However r _1, r _2, ··· the radius of curvature of each lens surface, d
₁ , d ₂ , ... Is the thickness of each lens and the lens interval, n
₁ , n ₂ ,... Are the refractive indices of each lens, ν ₁ , ν ₂ ,.
Is the Abbe number of each lens. In FIG. 11 and the data, r _{1 to} r ₂ are cover glasses, r _{3 to} r ₁₃ are objective optical systems O, r ₁₄ are object images by the objective optical system O, and r _{15 to} r ₃₅ are relay lenses R ₁ (r ₁₅ ~ R ₂₁ ), relay lens R ₂ (r
_{22 to} r ₂₈ ), a relay lens system including a relay lens R ₃ (r _{29 to} r ₃₅ ), and r ₃₆ is an image formed by an observation optical system including an objective optical system and a relay optical system.

The rigid endoscope of the present invention as described above is, for example, as shown in FIG. 34, a rigid endoscope 11 and an adapter 1.
2, a television camera head 13 including an image sensor, a camera control unit 14 that processes an electric signal obtained by the image sensor and converts the signal into a video signal, and a light source for supplying illumination light to the rigid endoscope 11. It is used in a system or the like composed of a monitor 16 for displaying a video signal. That is, the present invention is used for the rigid endoscope 11 and the like in FIG.

The observation optical system of the first embodiment of the rigid endoscope of the present invention is designed so that the angle of view is 130 ° at the designed image height, and an adapter and a TV camera should be attached thereto. Is designed to obtain a field of view of about 120 ° on the diagonal of the monitor. In the first embodiment, a light source side light guide 7 having NA = 0.66 is used, and the illumination light emitted from the light source is an image forming lens system as shown in FIG. And NA =
After being converted to 0.87, the light enters the insertion side light guide 2 with NA = 0.87. Here, the outer diameter of the light source side light guide of this embodiment is Φ ₃ = 4.5 mm, the outer diameter of the insertion portion side light guide is Φ ₄ = 3.4 mm, and its cross-sectional area is S ₂ =
It is 9.1 mm ² .

The outer diameter of the scope of this embodiment is 10 mm, and the outer diameter of the relay lens system R is 6 mm. In this example,
Since the angle of view is as wide as 130 ° as described above, the cross-sectional area S ₂ of the insertion-portion-side light guide can be reduced.
Therefore, the outer diameter of the cover glass C arranged closest to the object side of the objective optical system O can be increased. The outer diameter of the cover glass of this example is 7.4 mm, which is larger than the diameter of the conventional cover glass. Moreover, the cover glass C (r ₁ , r ₂ ) is formed by a plane parallel plate despite the wide angle of view of 130 °. This cover glass is made of Al ₂ O ₃
It is made of (artificial sapphire).

In the above-described embodiment, as shown in FIGS. 2 and 3, the cross-sectional area S ₂ of the insertion-portion-side light guide is small, and the tip end portion has a structure as shown in FIG. 40. The diameter of the cover glass C is larger than that of the rigid endoscope.

Further, the illumination optical system of this embodiment uses a condenser means 9 composed of _two positive lenses L ₁ and L _{2 as} shown in FIG. Further, as the light condensing means, a cover glass L ₃ formed of Al ₂ O ₃ having resistance to high temperature and high pressure steam sterilization is used.

The aberrations of the observation optical system (objective optical system + relay lens system) of this example are as shown in FIG.

FIG. 12 is a sectional view of the objective optical system of the second embodiment of the rigid endoscope of the present invention, which is a modification of the first embodiment. This embodiment is an objective optical system in which a prism that allows a 30 ° perspective view is inserted, and the configuration of the tip of the objective lens including the frame is as shown in FIG. In this figure, (A) is an end view as seen obliquely from the front, and (B) is a sectional view. This second
The data of the examples are as follows. Example 2 F number = 5.167, object point distance = 30, image height = 45.271, angle of view = 130 ° r ₁ = ∞ d ₁ = 0.4000 n ₁ = 1.76820 ν ₁ = 71.79 r ₂ = ∞ d ₂ = 0.2000 r ₃ ＝ ∞ d ₃ ＝ 0.5000 n ₂ = 1.88300 ν ₂ ＝ 40.78 r ₄ ＝ 1.4600 d ₄ ＝ 0.7500 r ₅ ＝ ∞ d ₅ ＝ 2.2220 n ₃ ＝ 1.80610 ν ₃ ＝ 40.95 r ₆ ＝ ∞ d ₆ ＝ 1.5500 n ₄ ＝ 1.80610 ν ₄ ＝ 40.95 r ₇ ＝ ∞ d ₇ ＝ 1.0247 n ₅ ＝ 1.80610 ν ₅ ＝ 40.95 r ₈ ＝ ∞ (aperture) d ₈ ＝ 1.0923 n ₆ ＝ 1.80610 ν ₆ ＝ 40.95 r ₉ ＝ ∞ d ₉ ＝ 1.5480 n ₇ ＝ 1.80610 ν ₇ = 40.95 r ₁₀ = ∞ d ₁₀ = 2.6000 n ₈ = 1.80610 ν ₈ = 40.95 r ₁₁ = -5.2880 d ₁₁ = 0.3000 r ₁₂ = 8.4830 d ₁₂ = 3.6500 n ₉ = 1.60311 ν ₉ = 60.68 r ₁₃ =- _{3.4700 d 13 = 1.3500 n 10 =} 1.84666 ν 10 = 23.78 r 14 = -7.8000 d 14 = 3.0200 r 15 = -3.7050 d 15 = 1.2000 n 11 = 1.76182 ν 11 = 26.52 r 16 = 14.0020 d 16 = 3.2000 n 12 = 1.77250 ν ₁₂ = 49.60 r ₁₇ = -5 .3520 d ₁₇ = 3.1100 r ₁₈ = ∞ (image) S ₂ = 9.08, S ₃ = 43.01, S ₄ = 28.27, | f _n /f|=0.668 This example is the same as the observation optical system shown in FIG. As shown in FIG. 12, the long lenses (r _{5 to} r ₇ ) in the objective optical system according to the first embodiment are oblique prisms P ₁ and P ₂ (r _{5 to} r ₁₀ ) and short convex lenses (r _{10 to} r ₁₁ ). Is replaced with. 3
0 ° perspective prism P _1, from P ₂ of the front end side concave lens (r
_{3 to} r ₄ ) and the cover glass C (r _{1 to} r ₂ ) are arranged obliquely with respect to the longitudinal direction of the scope so that the optical axis of the lens is aligned with the optical axes of the 30 ° oblique prisms P ₁ and P _2. ing. The lenses other than the 30 ° perspective prisms P ₁ and P ₂ and the short convex lenses (r _{10 to} r ₁₁ ) are the same as those in the first embodiment including the relay lens system.

In the second embodiment, by using a 30 ° perspective prism, light is incident on the incident surface (r ₅ ) of the prism P ₁ and transmitted through the transmission surface (r ₆ ) of the prism P ₂ and The light enters the surface (r ₆ ), is reflected by the reflection surface (r ₇ ), is then reflected by the surface (r ₉ ) on the prism P ₁ side, and is emitted from the surface (r ₁₀ ) on the convex lens side. Where prism P
Light rays ₁ and P ₂ are adhered to each other with an adhesive, and a light ray that passes through the transmission surface of the prism P ₁ and enters the surface of the prism P ₂ through the adhesive has an incident angle on each surface smaller than the total reflection angle. As it exists, it is transparent. In addition, the prism P of the prism P ₂
The surface on the _1st side is coated with aluminum only on the part where the effective light ray is incident, so that the light is reflected.
Further, the reflecting surface (r ₇ ) of the prism P ₂ has an absorption layer applied on the aluminum coat after vapor deposition of the aluminum coat, so that harmful light not involved in image formation is absorbed. The light reflected by the reflecting surface (r ₇ ) is reflected by the surface on which the aluminum coat is vapor-deposited and is emitted from the surface (r ₁₀ ) on the convex lens side. Also, the prisms P ₁ and P ₂
Is designed in consideration of the position of the reflection surface (r ₇ ) so that the overlap between the light ray transmitted through the joining surface and the light ray reflected by the surface is reduced. In order to prevent the harmful light indicated by the arrow in FIG. 12 from becoming a ghost, the harmful light that passes through a position of the joint surface that is not reflected by the aluminum coat is reflected by the reflection surface (r
The length of ₇ ) is lengthened so that it is absorbed by the absorption layer. At that time, the glass path length of the prism and the convex lens (r _{10 to} r ₁₁ )
The sum of the length of the glass path and the length of the glass path is made equal to the length of the glass path of the long lenses (r _{5 to} r ₇ ) of the first embodiment.

In this second embodiment, as shown in FIG. 13, the cross-sectional area S ₂ of the insertion side light guide (2) is smaller than the conventional one, and the cover glass C is larger than the conventional one. I know there is.

The diaphragm (virtual diaphragm) of the objective lens of this embodiment is located between the surface (r ₇ ) and the surface (r ₉ ), and is shown as r ₈ (diaphragm) in the data.

FIG. 14 is a cross-sectional view of the objective optical system of the third embodiment, and FIG. 35 is a view showing the state of the object side tip of the insertion section side light guide. The lens data of this third embodiment is as follows. Example 3 F number = 5.076, object distance = 30, image height = 2.235, field angle = 120 ° r ₁ = ∞ d ₁ = 0.7000 n ₁ = 1.76820 ν ₁ = 71.79 r ₂ = ∞ d ₂ = 0.2000 r ₃ ＝ ∞ d ₃ ＝ 0.5000 n ₂ = 1.88300 ν ₂ ＝ 40.78 r ₄ ＝ 1.4834 d ₄ ＝ 0.7500 r ₅ ＝ ∞ d ₅ ＝ 4.7715 n ₃ ＝ 1.80610 ν ₃ ＝ 40.95 r ₆ ＝ ∞ (aperture) d ₆ ＝ 5.1926 n ₄ = 1.80610 ν ₄ ＝ 40.95 r ₇ ＝ -5.3242 d ₇ ＝ 0.3000 r ₈ ＝ 8.1833 d ₈ ＝ 3.6500 n ₅ ＝ 1.60311 ν ₅ ＝ 60.68 r ₉ ＝ -3.5971 d ₉ ＝ 1.3500 n ₆ ＝ 1.84666 ν ₆ ＝ 23.78 r _{10 = -8.0215 d 10 = 3.0200 r} 11 = -3.5773 d 11 = 1.2000 n 7 = 1.76182 ν 7 = 26.52 r 12 = 19.2444 d 12 = 3.2000 n 8 = 1.77250 ν 8 = 49.60 r 13 = -5.3719 d 13 = 3.1100 r ₁₄ = ∞ (image) S ₂ = 9.08, S ₃ = 28.27, S ₄ = 28.27, | f _n /f|=0.655 The objective lens of the third embodiment has a first objective lens as shown in FIG. Configuration similar to the objective lens of the embodiment The relay lens system of the three-time relay shown in FIG. 11 is connected behind the objective lens. The angle of view of this embodiment is 120 °
It is. The third embodiment is characterized in that, as shown in FIG. 35, each fiber of the insertion section side light guide is deflected in the visual field direction of the observation optical system at the distal end portion to improve the light distribution. This is an example of a mirror.

The aberration situation of the observation optical system (objective optical system + relay lens system) of the third embodiment is as shown in FIG.

The fourth embodiment of the rigid endoscope of the present invention is an observation optical system in which the diameter of the relay lens system of the first embodiment is increased to make it bright. Similar to the first embodiment, this embodiment is composed of an objective optical system and a relay optical system of three-time relay, of which the relay optical system is
While the outer diameter of the first embodiment was 6 mm, it was 7.4 mm.
Then, the NA was changed from 0.1 to 0.12 so that the brightness was about 1.4 times that of the first embodiment. Also in the objective optical system, the outer diameters of the lenses after the thick convex lenses (r _{5 to} r ₇ ) are 5.7 mm in the first embodiment, whereas they are as large as 7.1 mm in this embodiment. This allows high NA light to pass through. Further, since the image height of this embodiment is the same as that of the first embodiment, the cover glass should be composed of a plane parallel plate having a diameter of 7.4 mm, although it is a very wide angle of 130 °. Was completed. The illumination optical system of this embodiment is
It is the same as the illumination optical system of the first embodiment.

The lens data (values of r, d, n, ν, etc.) of the fourth embodiment are the same as those of the first embodiment. The aberration situation of the observation optical system (objective optical system + relay lens system) of the fourth embodiment is as shown in FIG.

The observation optical system used in the fifth embodiment of the rigid endoscope of the present invention has a construction as shown in FIG. 15 and has the following lens data. Example 5 F number = 3.676, object distance = 30, image height = 2.650, angle of view = 130 ° r ₁ = ∞ d ₁ = 0.4000 n ₁ = 1.76820 ν ₁ = 71.79 r ₂ = ∞ d ₂ = 0.2000 r ₃ ＝ ∞ d ₃ ＝ 0.7000 n ₂ = 1.88300 ν ₂ ＝ 40.78 r ₄ ＝ 1.8794 d ₄ ＝ 1.0500 r ₅ ＝ ∞ d ₅ ＝ 6.5386 n ₃ ＝ 1.88300 ν ₃ ＝ 40.78 r ₆ ＝ ∞ (aperture) d ₆ ＝ 2.3369 n ₄ = 1.88300 ν ₄ ＝ 40.78 r ₇ ＝ -3.7983 d ₇ ＝ 0.9440 r ₈ ＝ -3.1895 d ₈ ＝ 1.4160 n ₅ ＝ 1.75520 ν ₅ ＝ 27.51 r ₉ ＝ ∞ d ₉ ＝ 3.4456 n ₆ ＝ 1.78800 ν ₆ ＝ 47.38 r _{10 = -8.4390 d 10 = 0.7080 r} 11 = 8.5258 d 11 = 3.3040 n 7 = 1.72916 ν 7 = 54.68 r 12 = -16.8158 d 12 = 1.5428 r 13 = -6.9807 d 13 = 1.4160 n 8 = 1.77250 ν 8 = 27.51 _{r 14 = 9.1000 d 14 = 3.5908} n 9 = 1.77250 ν 9 = 49.60 r 15 = -10.7873 d 15 = 12.0081 r 16 = 20.6547 d 16 = 26.4320 n 10 = 1.77250 ν 10 = 49.60 r 17 = ∞ d 17 = 4.7200 n ₁₁ = 1.58913 ν ₁₁ = 61.18 _{r 18 = -7.7880 d 18 = 1.4160} n 12 = 1.83400 ν 12 = 37.17 r 19 = -21.2447 d 19 = 0.7080 r 20 = 31.3219 d 20 = 21.7120 n 13 = 1.80610 ν 13 = 40.95 r 21 = -31.7108 d 21 = _{0.7080 r 22 = 23.8718 d 22 =} 1.4160 n 14 = 1.83400 ν 14 = 37.17 r 23 = 8.4496 d 23 = 31.0344 n 15 = 1.58913 ν 15 = 61.18 r 24 = ∞ d 24 = 1.0827 r 25 = 95.5147 d 25 = 3.0000 n ₁₆ = 1.51633 ν ₁₆ = 64.15 r ₂₆ = -19.0748 d ₂₆ = 11.6080 r ₂₇ = 20.6547 d ₂₇ = 26.4320 n ₁₇ = 1.77250 ν ₁₇ = 49.60 r ₂₈ = ∞ d ₂₈ = 4.7200 n ₁₈ = 1.58913 ν ₁₈ = 61.18 r ₂₉ = -7.7880 d ₂₉ = 1.4160 n ₁₉ = 1.83400 ν ₁₉ = 37.17 r ₃₀ = -21.2447 d ₃₀ = 0.7080 r ₃₁ = 31.3219 d ₃₁ = 21.7120 n ₂₀ = 1.80610 ν ₂₀ = 40.95 r ₃₂ -31.3219 d ₃₂ = 0.7080 r _{33 = 21.2447 d 33 = 1.4160 n} 21 = 1.83400 ν 21 = 37.17 r 34 = 7.7880 d 34 = 4.7200 n 22 = 1.58913 ν 22 = 61.18 r 35 = ∞ d 35 = 26.4320 n 23 _{1.77250 ν 23 = 49.60 r 36 =} -20.6547 d 36 = 13.2160 r 37 = 20.6547 d 37 = 26.4320 n 24 = 1.77250 ν 24 = 49.60 r 38 = ∞ d 38 = 4.7200 n 25 = 1.58913 ν 25 = 61.18 r 39 = - 7.7880 d ₃₉ = 1.4160 n ₂₆ = 1.83400 ν ₂₆ = 37.17 r ₄₀ = -21.2447 d ₄₀ = 0.7080 r ₄₁ = 31.3219 d ₄₁ = 10.8560 n ₂₇ = 1.80610 ν ₂₇ = 40.95 r ₄₂ = ∞ d ₄₂ = 10.8560 n ₂₈ = 1.80610 v ₂₈ = 40.95 r ₄₃ = -31.3219 d ₄₃ = 0.7080 r ₄₄ = 21.2447 d ₄₄ = 1.4160 n ₂₉ = 1.83400 v ₂₉ = 37.17 r ₄₅ = 7.7880 d ₄₅ = 4.7200 n ₃₀ = 1.58913 v ₃₀ = 61.18 r ₄₆ = ∞ d _{46 = 26.4320 n 31 = 1.77250 ν} 31 = 49.60 r 47 = -20.6547 d 47 = 6.6080 r 48 = ∞ ( _{image) S 2 = 9.08, S 3} = 43.01, S 4 = 40.72, | f n /f|=0.858 In the fifth embodiment, the objective optical system (r _{1 to} r ₁₅ ) and three relay lenses R ₁ , R ₂ and R ₃ (r ₁₆ to r ₂₆ ; r ₂₇ to
r _36; are formed of a relay lens system consisting of r ₃₇ ~r _47). The observation optical system of this embodiment is characterized in that the objective optical system is designed with the same image height as that of the first embodiment, and a relay lens R ₁ (r _{16 to} r ₂₆ ) is a non-magnifying relay lens. After increasing the image height, the same relay lens R ₂ ,
The point is that two R ₃ are used for relaying. The outer diameter of the scope of the fifth embodiment is 10 mm, the outer diameter of the relay lens system is 7.2 mm, and the NA is 0.136, which is a very bright observation optical system.

The fifth embodiment also has a wide angle of view of 130 °, but since the objective optical system is designed with the same image height as that of the first embodiment, the cover glass is a plane parallel plate. You can do it.

Further, the illumination optical system of the fifth embodiment has NA = 0. 0 as shown in FIG. 10 as a condensing means for condensing the light from the light source side light guide on the end face of the insertion section side light guide.
It is characterized by using 87 conical fibers. The diameter of the entrance end face of this conical fiber is 4.5 mm, and the diameter of the exit end face is 3.4 mm.

The aberration situation of the observation optical system (objective optical system + relay lens system) of the fifth embodiment is as shown in FIG.

The sixth embodiment of the rigid endoscope of the present invention is the fifth embodiment.
The observation optical system that is brighter than the observation optical system of the fifth embodiment has a similar structure to that of the fifth embodiment and has the following data as shown in FIG. Example 6 F number = 3.123, object distance = 30, image height = 2.650, angle of view = 120 ° r ₁ = ∞ d ₁ = 0.7080 n ₁ = 1.76820 ν ₁ = 71.79 r ₂ = ∞ d ₂ = 0.2360 r ₃ ＝ ∞ d ₃ ＝ 0.7080 n ₂ = 1.88300 ν ₂ ＝ 40.78 r ₄ ＝ 2.3483 d ₄ ＝ 1.0620 r ₅ ＝ ∞ d ₅ ＝ 8.5425 n ₃ ＝ 1.88300 ν ₃ ＝ 40.78 r ₆ ＝ -4.6989 d ₆ ＝ 0.9440 r ₇ ＝ _{-4.5938 d 7 = 1.4160 n 4 =} 1.75520 ν 4 = 27.51 r 8 = 35.8854 d 8 = 3.4456 n 5 = 1.78800 ν 5 = 47.38 r 9 = -7.9931 d 9 = 0.7080 r 10 = 13.9135 d 10 = 3.3040 n 6 = 1.72916 ν ₆ = 54.68 r ₁₁ = -13.2286 d ₁₁ = 1.1389 r ₁₂ = -6.0551 d ₁₂ = 1.4160 n ₇ = 1.75520 ν ₇ = 27.51 r ₁₃ = 8.5000 d ₁₃ = 3.5111 n ₈ = 1.77250 ν ₈ = 49.60 r ₁₄ = _{-8.3903 d 14 = 13.3407 r 15 =} 20.6547 d 15 = 26.4320 n 9 = 1.77250 ν 9 = 49.60 r 16 = ∞ d 16 = 4.7200 n 10 = 1.58913 ν 10 = 61.18 r 17 = -7.7880 d 17 = 1.4160 n 11 = 1.83400 ν ₁₁ = 37.17 r _{18 = -21.2447 d 18 = 0.7080 r} 19 = 31.3219 d 19 = 21.7120 n 12 = 1.80610 ν 12 = 40.95 r 20 = -31.3219 d 20 = 0.7080 r 21 = 21.2447 d 21 = 1.4160 n 13 = 1.83400 ν 13 = 37.17 r ₂₂ = 7.7880 d ₂₂ = 4.7200 n ₁₄ = 1.58913 ν ₁₄ = 61.18 r ₂₃ = ∞ d ₂₃ = 26.4320 n ₁₅ = 1.77250 ν ₁₅ = 49.60 r ₂₄ = -20.6547 d ₂₄ = 13.2160 r ₂₅ = 20.6547 d ₂₅ = 26.4320 n ₁₆ = 1.77250 ν ₁₆ ＝ 49.60 r ₂₆ ＝ ∞ d ₂₆ ＝ 4.7200 n ₁₇ ＝ 1.58913 ν ₁₇ ＝ 61.18 r ₂₇ ＝ -7.7880 d ₂₇ ＝ 1.4160 n ₁₈ ＝ 1.83400 ν ₁₈ ＝ 37.17 r ₂₈ ＝ -21.2447 d ₂₈ ＝ 0.7080 r ₂₉ ＝ 31.3219 d ₂₉ ＝ 21.7120 n ₁₉ ＝ 1.80610 ν ₁₉ ＝ 40.95 r ₃₀ ＝ -31.3219 d ₃₀ ＝ 0.7080 r ₃₁ ＝ 21.2447 d ₃₁ ＝ 1.4160 n ₂₀ ＝ 1.83400 ν ₂₀ ＝ 37.17 r ₃₂ ＝ 7.7880 d ₃₂ ＝ 4.7200 n ₂₁ ＝ 1.58913 ν ₂₁ = 61.18 r ₃₃ = ∞ d ₃₃ = 26.4320 n ₂₂ = 1.77250 ν ₂₂ = 49.60 r ₃₄ = -20.6547 d ₃₄ = 13.2160 r ₃₅ = 20.6547 d ₃₅ = 26.4320 n ₂₃ = 1.77250 ν ₂₃ = 49.60 r ₃₆ = ∞ d ₃₆ = 4.7200 n ₂₄ = 1.58913 ν ₂₄ = 61.18 r ₃₇ = -7.7880 d ₃₇ = 1.4160 n ₂₅ = 1.83400 ν ₂₅ = 37.17 r ₃₈ = -21.2447 d ₃₈ = 0.7080 r ₃₉ = 31.3219 d ₃₉ = 10.8560 n ₂₆ = 1.80610 ν ₂₆ ＝ 40.95 r ₄₀ ＝ ∞ d ₄₀ = 10.8560 n ₂₇ ＝ 1.80610 ν ₂₇ ＝ 40.95 r ₄₁ ＝ -31.3219 d ₄₁ ＝ 0.7080 r ₄₂ ＝ 21.2447 d ₄₂ ＝ 1.4160 n ₂₈ ＝ 1.83400 ν ₂₈ = 37.17 r ₄₃ = 7.7880 d ₄₃ = 4.7200 n ₂₉ = 1.58913 ν ₂₉ = 61.18 r ₄₄ = ∞ d ₄₄ = 26.4320 n ₃₀ = 1.77250 ν ₃₀ = 49.60 r ₄₅ = -20.6547 d ₄₅ = 6.6080 r ₄₆ = ∞ ( Image) S ₂ = 9.08, S ₃ = 43.01, S ₄ = 40.72, | f _n /f|=0.890 In the observation optical system of the sixth embodiment, the objective optical system is similar to that of the fifth embodiment. However, the image height of the objective optical system is designed to be the same as the final image height of the observation optical system of the fifth embodiment. It is the construction of three relays the magnification of the relay lens.

In this embodiment, the outer diameter of the scope is 10 mm,
NA is 0.16, which is brighter than that of the fifth embodiment. In this embodiment, the image height of the objective optical system is large, but the angle of view is 120 ° and the cover glass is a plane parallel plate.

The aberrations of the observation optical system (objective optical system + relay lens system) of the sixth embodiment are as shown in FIG.

In the seventh embodiment of the rigid endoscope of the present invention, the observation optical system is a modification of the first embodiment, and the objective optical system is shown in FIG.
The same lens system as the relay lens system of the three-time relay of the first embodiment is used in the configuration shown in FIG.

The data of the objective optical system of the seventh embodiment are as follows. Example 7 F number = 5.089, object point distance = 30, image height = 2.278, angle of view = 130 ° r ₁ = ∞ d ₁ = 0.7000 n ₁ = 1.76820 ν ₁ = 71.79 r ₂ = 14.8000 d ₂ = 0.4000 r ₃ ＝ ∞ d ₃ ＝ 0.5000 n ₂ = 1.80610 ν ₂ ＝ 40.95 r ₄ ＝ 1.4980 d ₄ ＝ 0.7500 r ₅ ＝ ∞ d ₅ ＝ 4.4151 n ₃ ＝ 1.88300 ν ₃ ＝ 40.78 r ₆ ＝ ∞ (aperture) d ₆ ＝ 7.0449 n _{4 = 1.88300 ν 4 = 40.78 r} 7 = -6.5230 d 7 = 1.0100 r 8 = 7.7180 d 8 = 2.0400 n 5 = 1.58913 ν 5 = 61.18 r 9 = -4.8630 d 9 = 1.0500 n 6 = 1.84666 ν 6 = 23.78 r _{10 = -10.1420 d 10 = 4.4500 r} 11 = -3.3740 d 11 = 1.0300 n 7 = 1.78472 ν 7 = 25.68 r 12 = 17.8210 d 12 = 3.0200 n 8 = 1.77250 ν 8 = 49.60 r 13 = -5.1410 d 13 = 3.0000 r ₁₄ = ∞ (image) S ₂ = 9.08, S ₃ = 28.27, S ₄ = 28.27, | f _n /f|=0.649 | r _a / r _b | = 9.880 The objective optical system of this embodiment is the first Although the configuration is similar to the embodiment of Bar Glass (r ₁ ~r ₂₎ the Al ₂ O ₃
It is made of (artificial sapphire) and is a plano-concave lens with a concave surface having a diameter of 6 mm facing the image side. The angle of view is 130 °, which is the same as in the first embodiment. In the case of a wide-angle scope, the problem is that the ray height on the first surface of the cover glass increases.
Instead of increasing the outer diameter of the cover glass as in the first embodiment to form a plane parallel plate, a plano-concave lens having the same outer diameter as that of the conventional optical system is used as the cover glass as in the seventh embodiment. You can also

The aberrations of the observation optical system (objective optical system + relay lens system) of the seventh embodiment are as shown in FIG.

The eighth embodiment of the rigid endoscope of the present invention is a modification of the seventh embodiment of the observation optical system. As shown in FIG. 18, a prism for 30 ° perspective is inserted and arranged in the objective optical system. It is an example. The data of this 8th Example are as follows. Example 8 F number = 5.180, object distance = 30, image height = 2.278, angle of view = 130 ° r ₁ = ∞ d ₁ = 0.7000 n ₁ = 1.76820 ν ₁ = 71.79 r ₂ = 14.8000 d ₂ = 0.4000 r ₃ ＝ ∞ d ₃ ＝ 0.5000 n ₂ = 1.80610 ν ₂ ＝ 40.95 r ₄ ＝ 1.4980 d ₄ ＝ 0.7500 r ₅ ＝ ∞ d ₅ ＝ 2.4960 n ₃ ＝ 1.88300 ν ₃ ＝ 40.78 r ₆ ＝ ∞ d ₆ ＝ 1.7100 n ₄ ＝ 1.88300 ν ₄ = 40.78 r ₇ = ∞ d ₇ = 0.2072 n ₅ = 1.88300 ν ₅ = 40.78 r ₈ = ∞ (diaphragm) d ₈ = 2.1289 n ₆ = 1.88300 ν ₆ = 40.78 r ₉ = ∞ d ₉ = 1.5760 n ₇ = 1.88300 ν ₇ = 40.78 r ₁₀ = ∞ d ₁₀ = 3.3400 n ₈ = 1.88300 ν ₈ = 40.78 r ₁₁ = -6.5 230 d ₁₁ = 1.0100 r ₁₂ = 7.7180 d ₁₂ = 2.0400 n ₉ = 1.58913 ν ₉ = 61.18 r ₁₃ =- _{4.8630 d 13 = 1.0500 n 10 =} 1.84666 ν 10 = 23.78 r 14 = -10.1420 d 14 = 4.4500 r 15 = -3.3740 d 15 = 1.0300 n 11 = 1.78472 ν 11 = 25.68 r 16 = 17.8210 d 16 = 3.0200 n 12 = 1.77250 ν ₁₂ = 49.60 r ₁₇ = -5.1410 d ₁₇ = 3.0000 r ₁₈ = ∞ (image) S ₂ = 9.08, S ₃ = 28.27, S ₄ = 28.27, | f _n /f|=0.649 | r _a / r _b | = 9.880 The long lens (r _{5 to} r ₇ ) of the seventh embodiment shown in FIG. 17 is replaced with a 30 ° perspective prism (r _{5 to} r ₁₀ ) and a short convex lens (r _{10 to} r ₁₁ ). The lenses other than those are the same as those in the seventh embodiment including the relay optical system.

The ninth embodiment of the rigid endoscope of the present invention is the same as that of the seventh embodiment, but FIG. 36 shows the object side tip of the insertion section side light guide of the illumination optical system so as to improve the light distribution. As configured.

In this embodiment, the same observation optical system as that of the seventh embodiment is used, and a plano-concave lens having a diameter of 6 mm is used for the cover glass. Therefore, the tip portion of the rigid endoscope has a sufficient space. is there. Therefore, as shown in FIG. 36, a rigid endoscope with good light distribution can be achieved by bending the tip of the insertion-portion-side light guide on the object side with respect to the visual field direction of the rigid endoscope.

The tenth embodiment of the rigid endoscope of the present invention has an objective optical system having the structure shown in FIG. 19, and the data of the objective optical system are as follows. Example 10 F number = 3.387, object distance = 30, image height = 2.650, angle of view = 130 ° r ₁ = ∞ d ₁ = 0.6000 n ₁ = 1.76820 ν ₁ = 71.79 r ₂ = 20.0000 d ₂ = 0.3000 r ₃ ＝ ∞ d ₃ ＝ 0.7000 n ₂ = 1.88300 ν ₂ ＝ 40.78 r ₄ ＝ 2.4336 d ₄ ＝ 1.0500 r ₅ ＝ ∞ d ₅ ＝ 6.2036 n ₃ ＝ 1.88300 ν ₃ ＝ 40.78 r ₆ ＝ ∞ (aperture) d ₆ ＝ 2.3229 n ₄ = 1.88300 ν ₄ ＝ 40.78 r ₇ ＝ -5.0713 d ₇ ＝ 0.9440 r ₈ ＝ -4.9332 d ₈ ＝ 1.4160 n ₅ ＝ 1.75520 ν ₅ ＝ 27.51 r ₉ ＝ 21.2894 d ₉ ＝ 3.4456 n ₆ ＝ 1.78800 ν ₆ ＝ 47.38 r _{10 = -7.9125 d 10 = 0.7080 r} 11 = 14.6608 d 11 = 3.3040 n 7 = 1.72916 ν 7 = 54.68 r 12 = -14.1637 d 12 = 1.5428 r 13 = -6.1295 d 13 = 1.4160 n 8 = 1.75520 ν 8 = 27.51 r ₁₄ = 9.2000 d ₁₄ = 3.5908 n ₉ = 1.77250 ν ₉ = 49.60 r ₁₅ = -8.6370 d ₁₅ = 7.0733 S ₂ = 9.08, S ₃ = 40.72, S ₄ = 40.72, | f _n /f|=0.830 | r _a / r _b | = 8.218 this first Examples of the observation optical system, magnification of the relay lens R ₂ or relay lenses of three relays arranged three of R ₃ used in the relay lens system of Example of the objective optical system and the 5 shown in FIG. 19 It is composed of a system. The observation optical system of this embodiment is characterized in that the objective optical system has a configuration similar to that of the fifth embodiment, and the image height and the outer diameter of the objective optical system of the observation optical system of the fifth embodiment are increased. In addition, since a plano-concave lens is used for the cover glass, there is no problem due to the height of the light beam on the first surface, and the image height of the objective optical system is designed to be the final image height of the relay lens system. There is no need to use a lens.

Further, in the illumination optical system of this embodiment, NA = as shown in FIG. 10 used in the fifth embodiment as a light collecting means for collecting the light from the light source side light guide.
A 0.87 conical fiber is used.

The aberration situation of the observation optical system (objective optical system + relay lens system) of the tenth embodiment is as shown in FIG.

The eleventh embodiment of the present invention is an example of a rigid endoscope having an outer diameter of the insertion portion of 8 mm and a thin structure. The objective optical system used has a structure as shown in FIG. Is as follows. Example 11 F number = 5.097, object distance = 30, image height = 2.235, angle of view = 120 ° r ₁ = ∞ d ₁ = 0.7000 n ₁ = 1.76820 ν ₁ = 71.79 r ₂ = 23.3860 d ₂ = 0.4000 r ₃ ＝ ∞ d ₃ ＝ 0.5000 n ₂ = 1.80610 ν ₂ ＝ 40.95 r ₄ ＝ 1.4707 d ₄ ＝ 0.7500 r ₅ ＝ ∞ d ₅ ＝ 4.4097 n ₃ ＝ 1.88300 ν ₃ ＝ 40.78 r ₆ ＝ ∞ (aperture) d ₆ ＝ 7.023 n ₄ = 1.88300 ν ₄ ＝ 40.78 r ₇ ＝ -6.6260 d ₇ ＝ 1.0598 r ₈ ＝ 7.8732 d ₈ ＝ 2.0400 n ₅ ＝ 1.58913 ν ₅ ＝ 61.18 r ₉ ＝ -4.8831 d ₉ ＝ 1.0500 n ₆ ＝ 1.84666 ν ₆ ＝ 23.78 r ₁₀ = -9.9335 d ₁₀ = 4.6170 r ₁₁ = -3.3385 d ₁₁ = 1.0300 n ₇ = 1.78472 ν ₇ = 25.68 r ₁₂ = 16.4987 d ₁₂ = 3.0200 n ₈ = 1.77250 ν ₈ = 49.60 r ₁₃ = -5.0989 d ₁₃ = 3.0000 r ₁₄ = ∞ (image) S ₂ = 9.08, S ₃ = 22.90, S ₄ = 28.27, | f _n /f|=0.640 | r _a / r _b | = 15.901 This eleventh embodiment is the above objective. The lens and the same lens as the seventh embodiment It is constituted by a relay lens system of three relays by Renzu.

The objective optical system has a structure similar to that of the seventh embodiment as shown in FIG. 20, and Al _{2 is} used as a cover glass.
A plano-concave lens made of O ₃ (artificial sapphire) and having a concave surface facing the image side and having a diameter of 5.4 mm is used. The angle of view is 120 °. Even if the diameter of the insertion part is thinned to 8 mm, the angle of view is wide and 120 °, so the amount of the light guide on the insertion side can be reduced, and it is used for conventional rigid endoscopes with an outer diameter of 10 mm. It is possible to use a known relay lens system with the same diameter and maintain the conventional brightness.

The aberrations of the observation optical system (objective optical system + relay optical system) of the 11th embodiment are as shown in FIG.

As a twelfth embodiment of the observation optical system of the rigid endoscope of the present invention, an embodiment in which the diameter of the insertion portion is 12 mm using an objective optical system as shown in FIG. 21 is shown. This objective optical system has the following data. Example 12 F-number = 2.411, object point distance = 30, image height = 3.300, angle of view = 140 ° r ₁ = ∞ d ₁ = 0.6000 n ₁ = 1.76820 ν ₁ = 71.79 r ₂ = 120.0000 d ₂ = 0.4000 r ₃ = ∞ d ₃ = 0.7000 n ₂ = 1.88300 ν ₂ ＝ 40.78 r ₄ ＝ 2.7641 d ₄ ＝ 1.0500 r ₅ ＝ ∞ d ₅ ＝ 6.1691 n ₃ ＝ 1.88300 ν ₃ ＝ 40.78 r ₆ ＝ ∞ (aperture) d ₆ ＝ 2.4512 n ₄ = 1.88300 ν ₄ ＝ 40.78 r ₇ ＝ -5.6913 d ₇ ＝ 0.9440 r ₈ ＝ -4.9112 d ₈ ＝ 1.4160 n ₅ ＝ 1.75520 ν ₅ ＝ 27.51 r ₉ ＝ 5.3611 d ₉ ＝ 3.4456 n ₆ ＝ 1.78800 ν ₆ ＝ 47.38 r _{10 = -7.1341 d 10 = 0.7080 r} 11 = 13.4661 d 11 = 3.3040 n 7 = 1.72916 ν 7 = 54.68 r 12 = -17.8224 d 12 = 1.5428 r 13 = -5.7461 d 13 = 1.4160 n 8 = 1.77250 ν 8 = 27.51 _{r 14 = 35.0000 d 14 = 3.5908} n 9 = 1.77250 ν 9 = 49.60 r 15 = -8.3745 d 15 = 7.0733 S 2 = 7.85, S 3 = 70.88, S 4 = 70.88, | f n /f|=0.894 | r _a / r _b | = 43.414 this real Examples are the diameter of the lens by the objective optical system and the fifth embodiment of the relay lens similar to the relay lens 9.5mm
It is configured as a relay lens system of a three-time relay consisting of the lens system of.

The objective optical system of this example has a similar construction to the objective optical system of the tenth example, but has a large outer diameter. The cover glass is made of Al ₂ O ₃ (artificial sapphire) and has a diameter of 9.5 with the concave surface facing the image side.
A mm plano-concave lens is used. Further, the angle of view is 140 °, which is a very wide angle, and the amount of the light guide on the insertion portion side can be further reduced, whereby the diameter of the relay lens system can be increased and a bright rigid endoscope can be realized.

The aberrations of the observation optical system (objective optical system + relay lens system) of the twelfth embodiment are as shown in FIG.

The thirteenth embodiment of the present invention shown in FIG.
This is a combination of the observation optical system and the zoom lens system of the rigid endoscope of the first embodiment. FIG. 22 shows a combination of the eyepiece lens and the zoom lens system at the telephoto end of the thirteenth embodiment, and the data of this optical system are as follows. Example _{13 r 37 = ∞ d 37 =} 13.7900 r 38 = 17.2600 d 38 = 0.9000 n 21 = 1.78472 ν 21 = 25.71 r 39 = 6.6670 d 39 = 2.6000 n 22 = 1.66672 ν 22 = 48.32 r 40 = -16.4600 d 40 _{= 4.1500 r 41 = ∞ d 41} = 3.0000 n 23 = 1.76820 ν 23 = 71.79 r 42 = ∞ d 42 = 3.2000 r 43 = ∞ d 43 = 9.0000 n 24 = 1.51633 ν 24 = 64.15 r 44 = ∞ d 44 = 3.0000 _{r 45 = 13.7100 d 45 = 1.3700} n 25 = 1.71999 ν 25 = 50.25 r 46 = -13.7100 d 46 = 1.0000 n 26 = 1.78472 ν 26 = 25.71 r 47 = ∞ d 47 = D 1 r 48 = -7.3520 d 48 = 1.8000 n ₂₇ = 1.84666 ν ₂₇ ＝ 23.78 r ₄₉ ＝ -3.7150 d ₄₉ = 1.0000 n ₂₈ ＝ 1.63930 ν ₂₈ ＝ 44.88 r ₅₀ ＝ 8.7190 d ₅₀ ＝ D ₂ r ₅₁ ＝ 20.8230 d ₅₁ ＝ 3.0000 n ₂₉ ＝ 1.72916 ν ₂₉ ＝ 54.68 r ₅₂ = -16.5760 d ₅₂ = 0.3000 r ₅₃ = 10.4340 d ₅₃ = 4.8000 n ₃₀ = 1.51633 ν ₃₀ = 64.15 r ₅₄ = -10.4340 d ₅₄ = 0.8000 n ₃₁ = 1.84666 ν ₃₁ = 23.78 r ₅₅ = 82.2 840 d ₅₅ = D ₃ r ₅₆ = ∞ d ₅₆ = 1.0000 n ₃₂ = 1.51633 ν ₃₂ = 64.15 r ₅₇ = ∞ d ₅₇ = 10.3661 Wide end Tele end D ₁ 3.6413 6.2888 D ₂ 7.2251 1.1936 D ₃ 2.3078 5.6918 Figure 34 As described above, the surgery using the rigid endoscope is performed with the rigid endoscope 11, the adapter 12, and the television camera head 13.
And a camera control unit 14, a light source 15 and a monitor 16.

The thirteenth embodiment shows a case where a zoom lens system having a zoom ratio of 2 is used. The size of the image when the image becomes the largest on the solid-state image sensor is about twice the diagonal length of the solid-state image sensor.

In the thirteenth embodiment, the same observation optical system as that of the first embodiment is used as the observation optical system of the rigid endoscope, but this zoom lens system is connected to the observation optical system of the other embodiments. You may use it. Further, it is more preferable for the television camera head to be able to move the solid-state imaging device. Further, by combining the television camera head having such a movable solid-state image pickup device and the zoom lens as in the thirteenth embodiment, the rigid endoscope is not moved when the image is enlarged and displayed on the monitor. You can observe the part you want to observe.

The aberrations at the wide end and the tele end of the eyepiece optical system + observation optical system + zoom lens system of the thirteenth embodiment are as shown in FIGS. 32 and 33, respectively.

In each of the embodiments, the diaphragm plate is arranged in the relay lens system, the eyepiece optical system, etc., and its image exists at the diaphragm position. Therefore, the diaphragm shown in the data and the like includes the case where it is a virtual diaphragm.

The rigid endoscope of the present invention described above can achieve the object of the present invention not only by the ones described in the claims but also by the following items.

(1) In the invention described in claim 2 of the claims, a rigid endoscope in which the cover glass is a plane parallel plate.

(2) In the invention described in claim 2 of the claims, the cover glass is a negative lens having a concave surface facing the image side, and a rigid endoscope satisfying the following condition (4): .

(4) 3 ≦ r _a / r _b ≦ 80 (3) A rigid endoscope satisfying the following condition (5) in the invention described in the item (2).

(5) 0.5 ≦ | f _n /f|≦0.95 (4) In the invention described in claim 2 of the claims or the above (2) or (3) A rigid endoscope in which the cover glass is formed of a crystal containing Al ₂ O ₃ as a main component.

(5) The rigid endoscope according to the invention described in claim 1 wherein the condensing means comprises one or more positive lenses.

(6) In the invention described in claim 1 of the invention, the condensing means is a conical optical fiber bundle, and the portion facing the light guide on the light source side is the incident end surface and the opposite end surface. Is the exit end face, the rigid endoscope in which the NA of the conical optical fiber bundle and the ratio of the diameters of the entrance end face and the exit end face satisfy the following conditions (6) and (7).

(6) 0.6 ≦ NA ≦ 1 (7) 0.5 ≦ Φ _b / Φ _a ≦ 1 (7) In the invention described in the item (5) or (6), the insertion A rigid endoscope in which the optical fiber at the object-side tip of the light guide on the part side is deflected in the direction of the visual field of the observation optical system.

(8) A rigid endoscope according to the invention described in claim 1 wherein the condensing means is composed of at least one lens having a positive focal length.

A television for observing an image transmitted by the relay lens system and connected to the rear end of the rigid endoscope according to claim 1 on a television monitor. A rigid endoscope system comprising a camera, wherein the television camera includes a solid-state image sensor and a zoom lens system satisfying the following conditions (8) and (9). (8) 1.5 ≦ M _g ≦ 3 (9) 1.5 ≦ φ I _Tmax / I _TV ≦ 3

[0112]

According to the present invention, it is suitable for a wide-angle rigid endoscope using an image transmission relay lens and having an outer diameter of the insertion portion of 8 mm or more and 12 mm or less and a viewing angle of 90 ° or more and 150 ° or less. By defining the amount of the insertion side light guide and the outer diameter of the relay lesbian system, it is possible to realize a rigid endoscope with a wide field of view and a good light distribution.

[Brief description of drawings]

FIG. 1 is a diagram showing the overall configuration of a rigid endoscope of the present invention.

FIG. 2 is an enlarged cross-sectional view of the distal end portion of the rigid endoscope of the present invention.

FIG. 3 is an enlarged end view of the tip of the rigid endoscope of the present invention.

FIG. 4 is a diagram showing the relationship between NA, lens outer diameter, and image height in a relay lens.

FIG. 5 is a graph showing the relationship between the outer diameter of the insertion portion of the rigid endoscope and the amount of the light guide.

FIG. 6 is a diagram showing a light distribution characteristic on an emission end face of a light guide on a light source side.

FIG. 7 is a diagram showing a light distribution characteristic at an incident end surface of a light guide on the insertion portion side when passing through an ideal light converging means.

FIG. 8 is a diagram showing a relationship between a diameter of a light guide, an emission angle, an incident angle, and the like when light is condensed by a condensing unit used in the rigid endoscope of the present invention.

FIG. 9 is a diagram showing an example of a configuration of a light collecting means used in the present invention.

FIG. 10 is a view showing a conical optical fiber which is another example of the light collecting means used in the present invention.

FIG. 11 is a sectional view of a first embodiment of an observation optical system used in the rigid endoscope of the present invention.

FIG. 12 is a sectional view of an objective optical system used in a second embodiment of the rigid endoscope of the present invention.

FIG. 13 is a sectional view of the tip of the second embodiment.

FIG. 14 is a sectional view of an objective lens used in a third embodiment of the rigid endoscope of the present invention.

FIG. 15 is a sectional view of an observation optical system used in a fifth embodiment of the endoscope for a rigid endoscope of the present invention.

FIG. 16 is a sectional view of an observation optical system used in a sixth embodiment of the rigid endoscope of the present invention.

FIG. 17 is a sectional view of an objective optical system used in a seventh embodiment of the rigid endoscope of the present invention.

FIG. 18 is a sectional view of an objective optical system used in an eighth embodiment of the rigid endoscope of the present invention.

FIG. 19 is a sectional view of an objective optical system used in a tenth embodiment of the rigid endoscope of the present invention.

FIG. 20 is a sectional view of an objective optical system used in an eleventh embodiment of the rigid endoscope of the present invention.

FIG. 21 is a sectional view of an objective optical system used in a twelfth embodiment of the rigid endoscope of the present invention.

FIG. 22 is a diagram showing the configuration of an eyepiece optical system / zoom lens of a thirteenth embodiment of the rigid endoscope of the present invention.

FIG. 23 is an aberration curve diagram of the observation optical system according to the first embodiment of the present invention.

FIG. 24 is an aberration curve diagram of the observation optical system according to the third embodiment of the present invention.

FIG. 25 is an aberration curve diagram of the observation optical system according to the fourth embodiment of the present invention.

FIG. 26 is an aberration curve diagram of the observation optical system according to the fifth embodiment of the present invention.

FIG. 27 is an aberration curve diagram of the observation optical system according to the sixth embodiment of the present invention.

FIG. 28 is an aberration curve diagram of the observation optical system according to the seventh embodiment of the present invention.

FIG. 29 is an aberration curve diagram of the observation optical system according to the tenth embodiment of the present invention.

FIG. 30 is an aberration curve diagram of an observation optical system according to an eleventh embodiment of the present invention.

FIG. 31 is an aberration curve diagram of an observation optical system according to a twelfth embodiment of the present invention.

FIG. 32 is an aberration curve diagram at the wide end of the eyepiece optical system / zoom lens according to the thirteenth embodiment of the present invention.

FIG. 33 is an aberration curve diagram at the telephoto end of the eyepiece optical system / zoom lens of the thirteenth embodiment of the present invention.

FIG. 34 is a diagram showing the overall configuration of a system using a rigid endoscope.

FIG. 35 is a diagram showing an example of the configuration of the distal end portion of the insertion section side light guide of the rigid endoscope of the present invention.

FIG. 36 is a view showing another example of the configuration of the distal end portion of the insertion-portion-side light guide of the rigid endoscope of the present invention.

FIG. 37 is a sectional view of an observation optical system of a conventional rigid endoscope.

FIG. 38 is a diagram showing an example of a configuration of a distal end portion of an objective optical system of a conventional rigid endoscope.

FIG. 39 is a diagram showing the configuration of another objective optical system of a conventional rigid endoscope.

FIG. 40 is a cross-sectional view of a distal end portion of a conventional rigid endoscope.

[Explanation of symbols]

1 rigid endoscope insertion part, 2 insertion part side light guide, 7
Light source side light guide, 9 focusing means, O objective optical system, R relay lens system, C cover glass

[Procedure amendment]

[Submission date] July 24, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 1

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction contents]

[0010] The rigid endoscope of the present invention has a configuration as shown in FIGS. 1, 2 and 3, FIG. 1 is the overall configuration, FIG. 2 is an enlarged cross-sectional view of the tip portion, and FIG. 3 is an enlarged end surface of the tip portion. It is a figure (end view seen from the front end side). In these figures, the fiber tube 3 for accommodating the insertion side light guide 2 is housed in the outermost outer tube 1, and the fiber tube 3
A system tube 4 for arranging the relay lens system R is arranged inside of, and an objective tube 5 for accommodating the objective optical system O is arranged inside thereof.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction contents]

[0014] Brightness is maximized. Here, the outer diameter Φ ₁ of the insertion portion of the rigid endoscope and the amount S of the light guide when the brightness is maximized
_A graph showing the relationship between LGs is shown by the solid line in FIG.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0051

[Correction method] Change

[Correction contents]

As shown in FIG. 8, the end face of the light guide 7 on the light source side is placed at the front focus position f _F of the lens as the light converging means, and the end face of the insertion side light guide 2 is placed at the rear focus position f _B. I have. At that time, as described above, equations (d) and (e)
Satisfies the relationship shown in.

[Procedure Amendment 5]

[Document name to be amended] Drawing

[Correction target item name] FIG.

[Correction method] Change

[Correction contents]

FIG. 35

Claims (3)

[Claims] 1. A light source side light guide for transmitting light from a light source, an insertion side light guide for receiving and transmitting light emitted from the light source side light guide, the light source side light guide and the insertion side light guide. And an insertion section including an observation optical system including an objective optical system and a relay optical system. The insertion section has an outer diameter of 8 mm or more and 12 mm or less and a viewing angle of 90 °. Above 150 °,
A rigid endoscope characterized in that a cross-sectional area S ₂ of the insertion section side light guide satisfies the following condition (1). (1) 3 / sin ² θ <≦ S ₂ ≦ 14 / sin ² θ However, θ is 1/2 of the viewing angle. 2. The rigid endoscopy according to claim 1, further comprising a cover glass provided at a distal end portion of the insertion portion, and a cross sectional area S _{3 of the} cover glass satisfies the following condition (3). mirror. (3) 0.35 (S ₁ −S ₂ ) ≦ S ₃ ≦ 0.8 (S ₁ −S ₂ ) where S ₁ is the cross-sectional area of the insertion portion. 3. The rigid endoscope according to claim 1, wherein the cross-sectional area S ₄ of the relay lens system satisfies the following condition (2). (2) 0.35 (S ₁ −S ₂ ) ≦ S ₄ ≦ 0.8 (S ₁ −S ₂ ), where S ₁ is the cross-sectional area of the insertion portion.