JPH06138400A - Endoscope - Google Patents

Abstract

PURPOSE:To provide a side viewing type endoscope in which such structure that illuminating light is easily prevented from being directly made incident on a side viewing observation optical system is realized, which is excellent in illumination distribution in visual field and whose outside diameter is thinned. CONSTITUTION:An optical device 4 which acts to change the direction of an optical axis, and which forms the cross sectional shape of the leading edge part of the endoscope or a part of the shape of the leading edge part of the endoscope is provided, and the optical paths of the optical device 4 and the observation optical system 2 are independently constituted. A shield is easily arranged between the illumination optical system and the observation optical system 2 and the illuminating light is prevented from being directly made incident on the optical system 2. Since useless space is not formed between an endoscope main body and the optical device 4, the outside diameter of the endoscope main body does not become larger unnecessarily, and the outside diameter of the endoscope is thinned.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illumination optical system for an endoscope, especially for a side-view type endoscope having a small diameter.

[0002]

2. Description of the Related Art Currently, in a small-diameter direct-view endoscope,
Since a blind spot occurs on the side surface during observation, it is necessary to change the direction of the visual field, for example, side view. As such a side-view endoscope, the one shown in FIG. 6 is disclosed in Japanese Utility Model Laid-Open No. 62-94312. Figure 6
6A is a cross-sectional view taken along the axis of the endoscope, and FIG. 6B is a cross-sectional view taken along the line AA of FIG. 6A intersecting the axis. In this example, the notch window 21 is provided in the fiberscope 22,
A reflective optical element 2 having an optical reflective surface 26 at its tip.
5, the light emitted from the ride guide 27 is bent 90 degrees by the reflection optical element 25, illuminates the side from the cutout window 21, and the light reflected by the object is transmitted to the objective optical system 28 through the optical reflection surface 26. It is disclosed that a side view is performed with an incident structure. In the figure, 23 is a resin tube, 24
Is a resin, and 29 is a tip molding portion.

As an illumination optical system for a side-view endoscope, Japanese Utility Model Laid-Open No. 59-41322 discloses that illumination light is emitted from the tip surface of the light guide 11 as shown in FIG. The prism 12 is configured to be transmitted to the incident surface 12A of the prism 12, which is reflected by the reflecting surface 12B having the reflecting film 13 formed thereon, and to be emitted from the emitting surface 12C. 12C, reflective surface 1
It is proposed that the side surface 12D other than 2B is provided with a reflecting means.

[0004]

In the side-view endoscope described in Japanese Utility Model Laid-Open No. 62-94312, the illumination optical system and the observation optical system do not have independent optical paths (reflecting member). Is the same), and a part of the illumination light from the ride guide 27 is reflected by the optical reflection surface 26 and directly enters the observation optical system, and ghost and flare are strongly generated, resulting in extremely poor visibility. . Further, as a result of the illumination light being blocked by the tip portion of the endoscope, a wide area cannot be effectively illuminated, which poses a serious problem in practical use.

Further, in the side-view endoscope described in Japanese Utility Model Laid-Open No. 59-41322, light having a strong exit angle near 0 ° emitted from the light guide 11 is directed by the prism 12 in the optical axis direction. The illuminance distribution is not good, because it is simply converted and is not different from the direct illumination by the light guide. Moreover, even if the reflecting surface 12B is formed in an arc shape, the illuminance distribution thereof is improved only in one direction,
The illuminance distribution is not good. Furthermore, when the illuminance distribution in the visual field is improved by disposing a plurality of prisms 12, when the observation optical system and the illumination optical system are combined, a useless space is generated between them. However, there is a problem that the outer diameter of the endoscope body becomes larger than necessary.

In view of the above situation, the present invention realizes a structure that can easily prevent the illumination light from directly entering the side-viewing observation optical system, has a good illuminance distribution in the field of view, and reduces the outer diameter of the endoscope. An object of the present invention is to provide an illumination optical system for a side-viewing endoscope that can be used.

[0007]

An endoscope of the present invention comprises an observation optical system having a field converting optical element and an objective lens, a light guide and light emitted from the light guide directed in the observation visual field direction. An illumination optical system including an optical element for projecting is provided, wherein the optical element has a surface having substantially the same shape as the outer surface of the endoscope.

In particular, the optical element has a recess, and at least a part of the observation optical system has a shape that fits in the recess of the optical element.

The reflecting surface of the optical element has a curved reflecting surface.

[0010]

According to the present invention, the optical paths of the illumination optical system and the observation optical system are independent of each other, and the shape of the optical element is the sectional shape of the endoscope distal end portion or the partial shape of the endoscope distal end portion. It was done like this. Also, at least one optical element
A refracting or reflecting surface having two powers is provided, and illumination is performed so as to surround the observation optical system. As a result, the shield can be easily arranged between the illumination optical system and the observation optical system, and the illumination light can be prevented from directly entering the observation optical system. Since there is no wasted space between the endoscope body and the optical element, the outer diameter of the endoscope body does not become larger than necessary,
An illumination optical system for a side-viewing endoscope that can reduce the outer diameter of the endoscope is realized. Further, it is possible to diffuse the light emitted from the light guide to illuminate a wide range, eliminate the influence of parallax between the illumination range and the observation range, and obtain a good illuminance distribution in the visual field.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the endoscope illumination optical system of the present invention will be described below with reference to FIG. In FIG. 1, (a) is a sectional view taken along the optical axis, (b) is a plan view, and (c) is a side view seen from the tip side. The illumination light is transmitted to the front end side through the light guide 3, passes from the front end surface of the light guide 3 to the incident surface 6 of the optical element 4 that abuts on the front end surface, and silver (Ag), aluminum (Al) as reflecting means. It is configured to be reflected by the reflecting surface 5 on which the reflecting film 8 and the like are formed and emitted from the emitting surface 7. The light guide 3 is formed in a U shape so as to surround the image guide 1 and the observation optical system 2 including the side-view prism 2a and the objective lens 2b. Incidentally, 2c is a member for supporting the prism 2a. The side surfaces of the prism 2a and the lens 2b are rounded.

Since the reflecting surface 5 of the optical element 4 is spherical,
It has a positive power as a whole, and once the light incident from the light guide 3 is condensed, it is diffused in concentric circles, so a wider range is better than in the conventional example in which light is diffused in only one direction. Can be illuminated. Further, since the illumination optical system and the observation optical system are independent, it is possible to prevent the illumination light from directly entering the observation optical system and obtain a good observation image without flare, ghost, etc. it can. Further, since the shape of the optical element 4 is the cross-sectional shape of the distal end portion of the endoscope, not only a wasteful space is not created between the endoscope body and the optical element 4, but also the outer diameter of the endoscope body is reduced. Since it does not become larger than necessary, it is possible to realize an endoscope having a small outer diameter.

In the above embodiment, the light guide 3 is formed in a U shape, but the shape of the light guide 3 is not limited to this example. For example, as shown in FIG. 1D, the light guide 3 may be a semi-circular shape.

FIG. 2 shows a second embodiment of the endoscope illumination optical system of the present invention. In the figure, (a), (b) and (c) are the same as in the case of FIG. In the second embodiment, the optical element 4 is provided with a notch in the optical element 4 shown in the first embodiment, and the side-view prism 2a is fitted therein to be integrated, and a reflecting means is provided on the boundary surface thereof. It is provided. By arranging in this way, the illumination optical system can surround the observation optical system 2, and the light distribution characteristic in the observation visual field when the object comes to a close position becomes good. Further, since the boundary surface between the observation optical system 2 and the optical element 4 is a reflecting surface, in the case of the first embodiment, the light rays that have been totally reflected on the exit surface and cause the decrease in the light quantity are reflected again, Since the light is emitted, it is possible to prevent the amount of illumination light from decreasing. In this example, the prism 2a, the objective lens 2b, etc. are formed in a square side surface.

FIG. 3 shows a third embodiment of the endoscope illumination optical system of the present invention. In the figure, (a) is a front view, (b),
(C) is the same as the case of FIG. In the third embodiment, the optical element 4 has a shape obtained by cutting a cylinder along its axis as shown by a broken line in FIG. Closely contact with 3,
Further, the other surface facing the incident surface 6 is inclined and cut as shown in FIG. 3 (e) to form the reflecting surface 5. The illumination light is emitted from the upper part of the cylindrical surface. A reflection film 8 is provided on the lower portion and the flat side surface 9b excluding the entrance surface 6, the reflection surface 5, and the exit surface 7 of the side surface 9a. As an actual configuration, the observation optical system 2 is sandwiched by using two optical elements 4 as shown in FIGS. 3B and 1C. In this example, the prism 2a is formed in a square shape, and the lens 2b is formed in a cylindrical side surface. Further, the member 2c that supports the prism 2a may be omitted.

According to the third embodiment, the illumination light is bent inward due to the columnar refracting surface of the exit surface 7, and illuminates toward the front of the observation optical system 2 so as to sandwich the observation visual field. Therefore, the effect of parallax is reduced during near-point observation, and the light distribution characteristics within the observation visual field are improved. Further, the optical element 4 can be formed by cutting a cylinder in the axial direction thereof, cutting the surface to be the incident surface 6 and the surface to be the reflecting surface 5, and polishing these surfaces (this In this case, the reflective film 8 is formed on the reflective surface 5 and the side surface later),
There is an effect that it can be easily manufactured and the manufacturing cost can be reduced.

FIG. 4 shows a fourth embodiment of the endoscope illumination optical system of the present invention. In the figure, (a), (b) and (c) are the same as in FIG. In the fourth embodiment, the optical element 4 is
As shown in FIG. 4D, the emission surface 7 is formed in a hollow cylindrical shape and the upper portion is cut parallel to the axial direction of the cylinder. An entrance surface 6 cut perpendicularly to the exit surface 7 and a reflection surface 5 cut obliquely on the other surface facing the entrance surface 6 are formed. A reflective film 8 is provided on the inner and outer cylindrical surfaces and the reflective surface 5.

According to the fourth embodiment, the optical element 4 has a U-shape, and the observation optical system 2 including the prism 2a and the lens 2b formed in a round shape is arranged inside the optical element 4. There is no wasted space, and when it is combined with the observation optical system 2, its sectional shape is the sectional shape of the endoscope, so the outer diameter of the endoscope main body does not become larger than necessary. Further, since the illumination light is emitted while sandwiching the observation optical system 2, it is possible to reduce the influence of parallax at the time of near point observation, and it is possible to perform good observation. Further, the light emitted from the light guide 3 is repeatedly reflected inside the optical element 4 and is emitted in the observation direction. At this time, since the side surface of the optical element 4 has a curvature, the emitted light is emitted with a wide range of angles, and therefore the light distribution characteristics are improved.

In the above embodiment, the light guide 3 is formed in a U-shape or a semicircle as shown in FIG. 5 (a), but it is not limited to this shape, and for example, FIG. As shown in (b), it may be configured as an assembly of light guide bundles.

[0020]

As described above, according to the endoscope illumination optical system of the present invention, it is possible to easily and effectively prevent the illumination light from entering the observation optical system, and the light distribution characteristic is excellent. Further, it has an advantage that the outer diameter of the endoscope can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration example of a first embodiment of an endoscope illumination optical system of the present invention.

FIG. 2 is a diagram showing a configuration example of a second embodiment of an endoscope illumination optical system of the present invention.

FIG. 3 is a diagram showing a configuration example of a third embodiment of an endoscope illumination optical system of the present invention.

FIG. 4 is a diagram showing a configuration example of a fourth embodiment of an endoscope illumination optical system of the present invention.

FIG. 5 is a diagram showing a modification of the light guide according to the endoscope illumination optical system of the present invention.

FIG. 6 is a diagram showing a configuration example of a conventional endoscope illumination optical system.

FIG. 7 is a diagram showing another configuration example of a conventional endoscope illumination optical system.

[Explanation of symbols]

 1 Image Guide 2 Observation Optical System 3 Light Guide 4 Optical Element 5 Reflective Surface 6 Incident Surface 7 Exit Surface 8 Reflective Film 9 Side Surface

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[Procedure amendment]

[Submission date] December 4, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

Since the reflecting surface 5 of the optical element 4 is spherical,
It has a positive power as a whole, and once the light incident from the light guide 3 is condensed, it is diffused in concentric circles, so a wider range is better than in the conventional example in which light is diffused in only one direction. Can be illuminated. Further, since the illumination optical system and the observation optical system are independent, it is possible to prevent the illumination light from directly entering the observation optical system and obtain a good observation image without flare, ghost, etc. it can. Furthermore, since the shape of the optical element 4 is the cross-sectional shape of the distal end portion of the endoscope, there is no wasted space between the endoscope body and the optical element 4, so that the outer diameter of the endoscope body is Since it does not become larger than necessary, it is possible to realize an endoscope having a small outer diameter.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0015

[Correction method] Change

[Correction content]

FIG. 3 shows a third embodiment of the endoscope illumination optical system of the present invention. In the figure, (a) is a side view, (b),
(C) is the same as the case of FIG. In the third embodiment, the optical element 4 has a shape in which a cylinder is cut along its axis as shown by a broken line in FIG. Closely contact with 3,
Further, the other surface facing the incident surface 6 is inclined and cut as shown in FIG. 3 (e) to form the reflecting surface 5. The illumination light is emitted from the upper part of the cylindrical surface. A reflection film 8 is provided on the lower portion and the flat side surface 9b excluding the entrance surface 6, the reflection surface 5, and the exit surface 7 of the side surface 9a. As an actual configuration, two optical elements 4 are used to sandwich the observation optical system 2 as shown in FIGS. 3B and 3C. In this example, the prism 2a is formed in a square shape, and the lens 2b is formed in a cylindrical shape on the side surface. Further, the member 2c that supports the prism 2a may be omitted. ─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] December 4, 1992

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

Claims (3)

[Claims] 1. An illumination optical system including an observation optical system including a field converting optical element and an objective lens, a light guide, and an optical element for projecting light emitted from the light guide toward an observation visual field direction. An endoscope including a system, wherein the optical element has a surface having a shape substantially the same as an outer surface of the endoscope. 2. The endoscope according to claim 1, wherein the optical element has a recess, and at least a part of the observation optical system has a shape that fits in the recess. 3. The endoscope according to claim 1, wherein the reflecting surface of the optical element has a curved reflecting surface.