JPH05142486A - Tip part of endoscope - Google Patents

Abstract

PURPOSE:To obtain the tip part of the endoscope which enables a light shield mask to securely be fixed and eliminates the shielding of an optical path with an adhesive. CONSTITUTION:At the tip part of the endoscope provided with the light shield mask 37 which cuts off excessive incident light halfway among plural optical components 13a, 33, 35, and 36 constituting an objective system 13 provided in the insertion part tip 11 of the endoscope, at least part of the external edge part of the light shield mask 37 is bent in parallel to the optical axis and the bent surface is joined with the external surface of the optical components 13a, 33, 35, and 36 or the internal surface of a cylinder body 34 where the optical components 13a, 33, 35, and 36 are fixed. In another way, the light shield mask 237 is sandwiched between an annular body 236 fitted on the internal surface of the cylinder body 34 where the optical components 13a, 33, 35, and 36 are fitted and fixed and the optical components 13a, 33, 35, and 36, and the annular body 236 is joined and fixed to the internal surface of the cylinder body 34.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a light-shielding mask for blocking excess incident light in the middle of a plurality of optical components constituting an objective optical system provided in the distal end of an insertion portion of an endoscope. It relates to the tip of an endoscope.

[0002]

2. Description of the Related Art An objective optical system of an endoscope is provided with a brightness diaphragm and a field diaphragm. However, with this alone, unnecessary peripheral light incident unnecessarily is reflected by the inner surface of the lens frame, etc. And ghosts may occur.

Therefore, conventionally, for example, a plate-shaped thin light-shielding mask 92 as shown in FIG. 8 is arranged in the middle of an optical component constituting the objective optical system, and the light-shielding mask 92 is bonded onto the surface of the optical component. And was blocking the extra ambient light. The shaded area in FIG. 8 is the adhesive surface.

[0004]

However, the light-shielding mask 9
If 2 is glued to the surface of the optical component, it should be glued (shaded area)
Is generally very small, and as a result, as shown in FIG. 8, the adhesive 93 often sticks out inside the light-shielding mask 92 and blocks the optical path.

Therefore, if the amount of the adhesive is reduced in order to prevent the adhesive from squeezing out, the light-shielding mask 92 will be peeled off later when a shock is applied to the distal end portion of the endoscope, and the objective optical system. There was a situation in which it had to be disassembled and repaired.

Therefore, an object of the present invention is to provide a distal end portion of an endoscope which can securely fix a light-shielding mask and which does not block an optical path by an adhesive.

[0007]

In order to achieve the above-mentioned object, the distal end portion of the endoscope of the present invention comprises a plurality of optical parts which constitute an objective optical system provided in the distal end portion of the insertion portion of the endoscope. At the tip of the endoscope provided with a light-shielding mask for blocking excess incident light, at least a part of the outer edge of the light-shielding mask was bent in a direction parallel to the optical axis, and was bent. The surface is joined to the outer surface of the optical component.

Further, at least a part of the outer edge portion of the light-shielding mask may be bent in a direction parallel to the optical axis, and the bent surface may be bonded to the inner surface of the cylindrical body to which the optical component is fixed. The optical component is fitted and fixed to the inner surface of the tubular body, and the light-shielding mask is sandwiched between the optical component and the annular body, and the annular body is bonded and fixed to the inner surface of the tubular body. Good.

[0009]

Embodiments will be described with reference to the drawings. Figure 1
The tip of the insertion part of an endoscope is shown.

In the drawing, reference numeral 1 denotes a curved portion formed at the tip of an elongated flexible tube forming an insertion portion, and a plurality of node rings 2 are rotatably connected by rivets 3. The outer circumference is a mesh tube 4 made of thin metal wire and an outer tube 5 made of rubber.
Is covered by.

A bending operation wire 7 which is remotely pulled.
Is inserted into the wire guide 8 projecting inwardly from each node ring 2 so as to be able to move back and forth. The tip of each bending operation wire 7 is fixed to the wire guide 8 by silver brazing or the like. Reference numeral 9 denotes a stopper pipe that is fixed to the end of the wire guide 8 by silver brazing or the like to prevent it from coming off.

Reference numeral 11 denotes a tip body connected to the tip of the bending portion 1 via a connecting tube 12, and a metal body 11b.
And a head portion 11a made of an electrically insulating plastic and joined to the tip portion thereof.

The tip end main body 11 has a circular cross-sectional shape when viewed from the tip end side (left side in FIG. 1), and the objective optical system 13 is built in the head portion 11a. The objective optical system 13 is composed of a plurality of objective lenses 13a and optical components 35, 36, 33 other than the lenses arranged behind the objective lens 13a, the axial direction of which coincides with the axial direction of the tip end main body 11, The object in front is the subject. The observation window 14 is the objective optical system 1.
It is formed by the 3 most advanced lenses.

Reference numerals 15 and 16 denote lens frames in which the respective objective lenses 13a of the objective optical system 13 are fitted and adhered, and the outer lens frame 15 is joined to the head portion 11a of the tip body.
17 is an aperture stop. Reference numeral 18 is an O-ring for sealing.

Light guide fiber bundle 21 for illumination
The output end 21a of the optical axis is fixed to the head 11a of the tip body with its axis parallel to the objective optical system 13. A light distribution lens (concave lens) 22 for expanding the light distribution angle of the emitted illumination light is arranged on the end surface.

In this way, the light distribution lens 22 is used for the illumination window 2.
3 is formed, and the illuminating light transmitted through the illumination light guide fiber bundle 21 illuminates a subject in front of the tip end main body 11.

A solid-state image pickup device 31 is arranged in the body portion 11b of the tip portion main body 11. As the solid-state image sensor 31, for example, a CCD (charge coupled device) is used. An image receiving surface 31a of the solid-state image pickup device 31 is formed in a square or a rectangle, and is arranged parallel to the central axis of the objective optical system 13.

A right-angle prism 33 is arranged at the rear end of the objective optical system 13 so that the optical axis of the objective optical system 13 intersects perpendicularly with the center of the image receiving surface 31a of the solid-state image pickup device 31. It is reflected at a right angle.

Further, the right angle prism 33 and the objective lens 13
Between a and a, a low-pass filter 36 is inserted and fixed in the rear end of the connecting tube 34, which is connected and fixed to the rear end of the lens frame 16.

A color correction filter 35 having a diameter slightly smaller than that of the low-pass filter 36 is joined to the front side of the low-pass filter 36, and a light-shielding mask 37 is arranged so as to come into contact with the front surface of the color correction filter 35.

With such an arrangement, the image of the subject on the left side of FIG.
The image is formed on the image receiving surface 31a of. The light-shielding mask 37 is made of a thin metal plate, and as shown in FIG. 2, has a hole formed in the central effective optical path portion in accordance with the cross-sectional shape of the optical path so as to block light around the hole. There is. Then, the upper and lower outer edges are bent backward at a right angle in parallel with the optical axis, and the inner and outer surfaces of the bent surface are used as the bonding surfaces 37a and 37b.
The inner adhesive surface 37a is joined to the outer peripheral surface of the color correction filter 35, and the outer adhesive surface 37b is joined to the inner surface of the connecting tube 34.

Therefore, even if a sufficient amount of adhesive is applied to the adhesive surfaces 37a and 37b to secure sufficient adhesive strength, the adhesive does not extend to the optical path portion in the light-shielding mask 37, and the adhesive strength is ensured. It is possible to secure an unobstructed optical path and block excess ambient light with the light blocking mask 37.

In the above embodiment, the adhesive surfaces 37a, 37a
Although 7b is provided on two sides, the upper edge side and the lower edge side, in the present invention, at least one surface may be provided, and three or more surfaces may be provided. This also applies to other embodiments.

FIGS. 3 and 4 show a second embodiment, in which the upper and lower outer edge portions of the light-shielding mask 137 are bent forward at a right angle in parallel with the optical axis, and the outer surface 137a of the bent surface is bonded. The surface is joined to the inner surface of the connection cylinder 34, and the light shielding surface is brought into contact with the color correction filter 35. Even with this structure, the same effects as those of the first embodiment can be obtained.

5 and 6 show a third embodiment, in which a thin plate-shaped light shielding mask 237 is sandwiched between an annular body 236 fitted to the inner surface of the connecting cylinder 34 and the color correction filter 35. The outer peripheral surface of the annular body 236 is joined to the inner surface of the connecting cylinder 34. With this configuration, the adhesive surface and the light-shielding mask 237 are separated, so that the adhesive can be more completely prevented from protruding into the optical path.

FIG. 7 shows an image receiving surface 31a of the solid-state image pickup device 31.
The present invention is applied to an electronic endoscope in which is arranged perpendicularly to the optical axis of the objective lens 13a. Thus, the present invention can be applied to any type of electronic endoscope. It is also possible to apply to an endoscope in which an observation image is transmitted by an image guide fiber bundle.

[0027]

According to the distal end portion of the endoscope of the present invention, since the adhesive surface for fixing the light-shielding mask is provided on the portion other than the light-shielding surface of the light-shielding mask, the adhesive agent is sufficiently applied to the adhesive surface. The adhesive does not stick out into the optical path even after applying, and a strong adhesive strength can be obtained, and the light-shielding mask can be reliably fixed.

As a result, the work of adhering the light-shielding mask is greatly facilitated, and the light-shielding mask does not peel off even if a large shock is applied to the tip of the endoscope later.

[Brief description of drawings]

FIG. 1 is a side sectional view of a distal end portion of an endoscope of a first embodiment.

FIG. 2 is a partial perspective view of the first embodiment.

FIG. 3 is a partial perspective view of the second embodiment.

FIG. 4 is a partial side sectional view of the second embodiment.

FIG. 5 is a partial perspective view of the third embodiment.

FIG. 6 is a partial side sectional view of a third embodiment.

FIG. 7 is a side cross-sectional view of the distal end portion of the endoscope of the fourth embodiment.

FIG. 8 is a partial perspective view of a conventional example.

[Explanation of symbols]

 11 Tip Body 13 Objective Optical System 13a Objective Lens 33 Right Angle Prism 34 Connection Tube 35 Color Correction Filter 36 Low-pass Filter 37 Light-shielding Mask

Claims (3)

[Claims] 1. A distal end portion of an endoscope in which a light-shielding mask for blocking excess incident light is provided in the middle of a plurality of optical components forming an objective optical system provided in the distal end portion of an insertion portion of the endoscope. 2. The distal end portion of the endoscope according to, wherein at least a part of the outer edge portion of the light-shielding mask is bent in a direction parallel to the optical axis, and the bent surface is joined to the outer surface of the optical component. 2. A tip portion of an endoscope in which a light-shielding mask for blocking excess incident light is provided in the middle of a plurality of optical components forming an objective optical system provided in the tip portion of an insertion portion of the endoscope. In, at least a part of the outer edge portion of the light-shielding mask is bent in a direction parallel to the optical axis, and the bent surface is joined to the inner surface of the cylindrical body to which the optical component is fixed. The tip of the endoscope. 3. A distal end portion of an endoscope in which a light-shielding mask for blocking excess incident light is provided in the middle of a plurality of optical components constituting an objective optical system provided in the distal end portion of the insertion portion of the endoscope. In the above, the light-shielding mask is sandwiched between the annular body fitted to the inner surface of the tubular body to which the optical component is fitted and fixed, and the optical component, and the annular body is bonded and fixed to the inner surface of the tubular body. The tip of the endoscope characterized by.