JPH02287312A - Endoscope - Google Patents

Abstract

PURPOSE:To reduce the outside diameter of a lens holder which holds lens groups disposed behind a prism and to facilitate the insertion of a front end part into a body cavity by deviating the center axis of the lens holder from the optical axis of the lens groups. CONSTITUTION:The lens groups 26 to 28 disposed behind the prism 25 are held by the lens holder 30. The center axis of the inside diameter of the lens holder 30 is deviated from the center axis of the outside diameter thereof and the center axis of the inside diameter aligns to the optical axis of the lens groups 26 to 28. More than a needed increase in the outside diameter of the lens holder 30 is, therefore, obviated and the outside diameter of the front end part is formed to the smaller outside diameter than in case of using the lens holder having the center of the outside diameter and the center of the inside diameter coaxial with each other. The insertion of the front end part into the body cavity is facilitated in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an endoscope, and more particularly to an endoscope equipped with a front oblique viewing optical system at the distal end of an insertion section.

[Conventional technology]

In recent years, ultrasound endoscopes have been developed that allow the insertion part to be inserted into a body cavity to optically observe the inner wall of the stomach, etc., as well as to obtain ultrasound tomographic images corresponding to the observed area. There is. The observation optical system of this ultrasonic endoscope is equipped with an ultrasonic probe at the tip of the insertion section, so the viewing direction is forward at an angle of about 30'' to 60'' with respect to the axial direction of the insertion section. As a front perspective type lens system disposed at the distal end of the insertion section, there are two types: one using a roof prism and the other using a prism 61 having a shape as shown in FIG. Here, since roof prisms are generally large in shape, if a front perspective lens system using a roof prism is placed at the tip of the insertion tube, the outer diameter of the tip will become large, making it difficult to insert into the body cavity. . In particular, ultrasound endoscopes that have ultrasound functions added to regular endoscopes have an image guide, light guide, air and water supply tube, and an ultrasound probe inside the insertion section. Since the hollow drive shaft is provided over almost the entire length of the insertion section, the outer diameter of the tip end becomes larger. For this reason, the tip of the insertion section of the ultrasound endoscope is
A lens system using a prism at as shown in FIG. 14 is arranged.

[Problem to be solved by the invention]

However, in the past, as shown in FIG.
1 and the central axis of the lens holder 65 that holds the lens groups 82, 63, and 84 arranged behind the lens group 62, θ
Since the optical axes of lenses 3 and 04 were aligned, the lens holder 6
There was a problem in that the outer diameter of No. 5 was larger than necessary.

The present invention was made by focusing on these problems.
It is an object of the present invention to provide an endoscope that can be easily inserted into a body cavity without making the outer diameter of a lens holder larger than necessary.

[Means to solve the problem]

To achieve the above object, the present invention provides an endoscope equipped with a front perspective type observation optical system in which a plurality of lens groups and a prism are arranged at the distal end of an insertion section. The central axis of a lens holder that holds a lens group is eccentric with respect to the optical axis of the lens group.

[For production]

In the present invention, by decentering the central axis of the lens holder with respect to the optical axis of the lens group, the outer diameter of the lens holder can be reduced, and the tip portion can be made smaller in diameter.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

1 to 13 show an embodiment in which the present invention is applied to an ultrasonic endoscope, and FIG. 1 is a diagram showing the overall configuration thereof. In the figure, reference numeral 1 denotes an insertion section formed by connecting a distal end portion 4 to the distal end of a flexible tube 2 via a curved tube 3, and an ultrasonic operating section 5 and an endoscope at the rear end of this insertion section 1. The operating units 6 are connected in series. ”2 The ultrasonic operating unit 5 houses a motor, an encoder, etc. that rotationally drives the ultrasonic probe provided at the tip of the insertion unit 1, and the endoscope operating unit 6
is provided with an operation knob 7 for bending the bending pipe 3, an air/water supply button 8, etc. Furthermore, a universal cord 9 and an electric cable cord 10 are connected to the endoscope operation unit 6, and a connector 11 connected to a light source device (not shown) is connected to the electric cable cord lO at the tip of the universal cord 9. There is an ultrasonic observation device (not shown) at the tip of the
A connector 12 connected to each is provided.

Note that the eyepiece section 1 of the observation optical system is located at the rear end of the endoscope operation section 6.
3 is provided.

Details of the tip portion 4 are shown in FIGS. 2 to 13.

2 to 13, 14 is a tip body connected to the tip of the curved tube 3, and the tip of the tip body 14 has a cannonball shape made of a material with good ultrasonic transparency. A tip cover 15 is provided. This tip cover 15
An ultrasonic probe 16 is housed inside, and an ultrasonic transmission medium 17 is enclosed. The ultrasonic probe 16 is rotatably provided with respect to the tip main body 14 by a sliding bearing 18, and the ultrasonic operating section 5 It is designed to be driven by a driving means such as a motor provided in the.

On the other hand, on the side surface of the tip main body 14, there is a notch 2 having an inclined surface 20a of approximately 45@ with respect to the axial direction of the insertion portion 1.
0 is formed. Slanted surface 20a of this notch 20
As shown in FIGS. 3 to 5, there are an observation window (cover glass) 21, an illumination lens 22, 23, and an air/water supply nozzle 2.
4 are provided. Inside the observation window 21, there is a 10th
As shown in the figure, a prism 25 is arranged, and this prism 25 tilts the field of view of the observation optical system forward 45'' with respect to the axial direction of the insertion section 1. The lens groups 2G, 27, 28 and the image guide fiber bundle 29 are arranged along the axial direction of the insertion section 1, and the lens groups 2G, 27.
．． 28 is held by a lens holder 30. In this lens holder 30, the central axis of the inner diameter and the central axis of the outer diameter are eccentric, and the central axis of the inner diameter coincides with the optical axis of the lens group 2L 27, 28. Note that the lens holder 30 has a part of the wall thickness on the rear end side where the image guide fiber bundle 29 is inserted thinned, and the thin part is made into a deer shape with a fixing screw 31 and is detachably fixed to the tip body 14. has been done.

Also, a rotation stopper 3 is located on the opposite side of the fixing screw 31.
2 is provided, and this rotation stopper screw 32 locks the lens holder 3.
0 is positioned and fixed to the tip body 14.

Among the illumination lenses 22 and 23, the auxiliary illumination lens 23
As shown in FIG. 11, the emitted light is inclined forward with respect to the inclined surface 20a, so that the field of view of the observation optical system is covered by the two illumination optical systems.

Note that the sides of the recess 33 formed between the light emitting part of the illumination lens 23 and the inclined surface 20a extend to the end of the notch 20 and are open, so that water and dirt do not accumulate in the four parts 33. That's how it is. The two light guide fiber bundles 34 and 35 of the illumination optical system are bent within the tip body 14, and a straight line from the bent portion to the rear end side is connected to the illumination lens 22.23 on the tip side. The part has a cap of 38
．． 37 is covered, and the bent portion between them is molded with adhesive. Note that an oval storage chamber 38 for storing the light guide fiber bundles 34 and 35 is formed in the tip main body 14, and is sealed watertightly by a light guide lid 39. The storage chamber 38 is provided with a spacer 40 for maintaining the distance between the light guide fiber bundles 34 and 35, and is filled with a sealing material.

Further, the notch portion 20 is provided with an opening 41 that communicates with a forceps port provided in the operating portion 6 via a channel, and a forceps stand 4 for changing the direction of a treatment instrument such as forceps.
2 is provided near the opening 4I. This forceps stand 42 is adapted to rotate about a support 44 as a fulcrum as shown in FIG. 9 by pulling a wire 43. In addition,
As shown in FIGS. 12 and 13, inside the tip body 14, there are provided a water supply pipe 45 and a drainage pipe 46 for supplying and discharging water to the inside of a balloon (not shown) provided on the outside of the tip cover 15. It is being

The ultra-8′ endoscope configured in this manner includes lens groups 26, 27, and 26 disposed behind the prism 25, as described above.
Since the outer diameter center and the inner diameter center of the lens holder 30 holding the lens holder 28 are eccentric, the outer diameter of the lens holder 30 does not become larger than necessary, and it is possible to use a lens holder whose outer diameter center and inner diameter center are coaxial. The outer diameter of the distal end portion 4 can be made smaller than that in the case where the tip portion 4 is used.

In addition, in this embodiment, the exit surface of the illumination lens 23 and the inclined surface 2
The side of the four parts 33 formed between the cut part 20 and the
Since the opening extends to the end of the opening, it is difficult for water and dirt to accumulate in the four parts 33, and a reduction in the amount of illumination light due to water and dirt can be prevented. Furthermore, since the two light guide fiber bundles 34 and 35 are stored in one storage chamber 38, the limited space can be used effectively.
The outer diameter of the can be made smaller.

In the above embodiments, the present invention was applied to an ultrasonic endoscope, but the present invention is not limited to this, and can be applied to all endoscopes equipped with a front perspective type observation optical system. Applicable.

〔Effect of the invention〕

As explained above, the present invention applies to the distal end of the insertion section. 12
In an endoscope equipped with a front perspective type observation optical system formed by arranging several lenses and a prism, the central axis of a lens holder that holds a lens group arranged behind the prism is aligned with the light of the lens group. It is eccentric to the axis. Therefore, the outer diameter of the lens holder does not become larger than necessary, and the outer diameter of the tip can be made thinner than when using a lens holder in which the center of the outer diameter and the center of the inner diameter are coaxial.
An endoscope that can be easily inserted into a body cavity can be provided.

[Brief explanation of drawings]

1 to 13 show an embodiment of the present invention, FIG. 1 is a general configuration diagram of an ultrasound endoscope, FIG. 2 is a sectional view of the tip of the insertion section, and FIG. 3 is a sectional view of the tip of the insertion section. 4 is a front view of the distal end of the insertion section, FIG. 5 is a view taken in the direction of the arrow shown in FIG. 2, and FIG. 6 is a sectional view taken along the line B-B in FIG. 7 is a sectional view taken along the line C-C in FIG. 2, FIG. 8 is a sectional view taken along the line DD in FIG. 2, FIG. 9 is a sectional view taken along the line E-E in FIG. The figure is a sectional view taken along the arrow F-F in Fig. 5, and Fig. 11 is a cross-sectional view taken along the line G-F in Fig. 5.
12 is a sectional view taken along line H-H in FIG. 8;
Figure 13 is like Figure 8! -1 arrow sectional view and FIG. 14 are explanatory diagrams of the prior art. 1... Insertion part, 2... Flexible tube, 3... Curved tube, 4
...Tip part, 5...Ultrasonic operation part, 6...Endoscope operation part, 13...Eyepiece part, 14...Tip part main body, 1
5...Tip cover 18...Ultrasonic probe, 19.
...Hollow shaft, 21...Observation window, 22, 23...Illumination lens, 24...Air and water supply nozzle, 25...Prism, 2G, 27.28...Lens, 29... Image guide fiber bundle, 30... Lens holder, 34, 35... Light guide fiber bundle.

Claims (1)

[Claims] In an endoscope equipped with a front perspective observation optical system consisting of multiple lens groups and prisms arranged at the distal end of the insertion section,
An endoscope characterized in that a central axis of a lens holder that holds a lens group arranged behind the prism is eccentric with respect to an optical axis of the lens group.