JPH0833516B2 - Endoscope - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an observation optical system for an endoscope, and more specifically, a support means for the observation optical system including an objective lens arranged at the distal end of the endoscope. It is about.

[Prior Art] As is well known, an endoscope to be inserted into a body cavity for medical examination or treatment is operated with an endoscope operation section provided with an eyepiece section and an air / water feeding piston. Body cavity insertion part having an observation window, an illumination window, an air / water supply nozzle, an opening of a forceps channel, etc. on the distal end surface, and a connector on the distal end portion connected to the operation part. And a light guide cable having a vent hole for water leak inspection.

The insertion portion in the body cavity is composed of a flexible tube portion, a curved tube portion and a tip forming portion, and the tip forming portion has an objective lens of an observation optical system and an image receiving tip portion of an optical image transmitting member, an illumination window and A distal end portion of the illumination light transmitting member, an air / water feeding nozzle, a connecting pipe of the air / water feeding tube, and a channel opening portion through which forceps and the like are inserted are provided.

In addition, in recent years, this tip component has been used for high-frequency cautery treatment of the affected area with a high-frequency treatment instrument having a forceps channel of an endoscope inserted therein. It is composed of a plurality of blocks to ensure the length. That is, the front block body forming the outer surface of the tip portion is made of an electrically insulating member such as a synthetic resin, and the block body of the rear portion is made of a metal block body also called a tip fitting.

In the conventional tip structure portion configured in this way, the objective lens support frame holding the objective lens of the observation optical system is fixed in the synthetic resin block body, and the image of the image guide fiber which is the optical image transmission member is received. The front end of the device, or the solid-state image sensor such as CCD is fixed inside the metal block.

[Problems to be solved by the invention]

However, in the conventional endoscope distal end portion configured as described above, the objective lens support frame and the image receiving portion of the optical image transmitting member are fixed to the block bodies that are separate bodies, respectively. It has been very difficult to align the optical axis of the lens with the central axis of the image receiving section, and the optical axis is often misaligned between them.

When this optical axis shift occurs, the periphery of the observation visual field is vignetted, aberrations occur, and the like, and the observation accuracy is greatly deteriorated.

Therefore, an object of the present invention is to eliminate the drawbacks of the conventional supporting means of the observation optical system, and to observe an endoscope in which the optical axis is absolutely not deviated between the objective lens and the image receiving portion due to its structure. It is to provide a support means for the optical system.

[Means and Actions for Solving Problems]

The support means for the observation optical system of the endoscope according to the present invention is an endoscope including an objective lens system and an image receiving portion for receiving an image from the objective lens system in the distal end constituting portion, and all of the objective lens systems are constituted. And a support cylinder for supporting the lens and the image receiving portion, the tip forming portion is divided into a front block and a rear block, and a fitting hole for fitting and supporting the support cylinder is provided in the rear block and the front block. A through hole into which the support cylinder is loosely fitted is provided, and the support cylinder is arranged so as to straddle the through hole and the fitting hole. The objective lens support frame and the objective lens The image receiving end of the optical image transmitting member, the image receiving surface of which is disposed at the image forming position, is fitted in the same support cylinder.

[Embodiment] The present invention will be described below with reference to one embodiment shown in the drawings.

FIG. 2 shows the overall configuration of an endoscope to which the present invention is applied. The endoscope includes an operation section 1 of the endoscope provided with an eyepiece section 9 for observation and an air / water supply piston 12, and a body cavity insertion section 2 connected to the operation section 1 respectively. It is composed of a light guide cable 8.

The body cavity insertion portion 2 is composed of a flexible tube portion, a curved tube portion and a tip forming portion, and an observation window 4, illumination windows 5a, 5b, an air / water feeding nozzle 6 are provided on the tip surface of the tip forming portion 3. A channel opening 7 through which forceps and the like are inserted is provided. The light guide cable 8 has a built-in light guide composed of a fiber bundle for illumination, and a connector 10 for connecting the cable 8 to a light source device (not shown) is attached to the tip of the light guide. Vent 11 for water leak inspection is provided at 10.

In the endoscope configured as described above, by operating the air / water feeding piston 12 provided in the operation portion 1, water is supplied from the nozzle 6 to the outer surface of the observation window 4. Air is supplied so that the outer surface of the outermost surface lens l ₁ (see FIG. 1) forming the window 4 can be cleaned.

FIG. 1 is a cross-sectional view of a main part of the tip forming portion 3 according to the present invention. The tip forming portion 3 is formed of a plurality of block bodies 18 and 21, and the front block body 18 made of a synthetic resin having a tip end portion forms an outer surface of the tip portion and is integrally combined with this. The rear part of the block
Reference numeral 21 is a metal block body also called a tip fitting, to which the tip of a flexible outer tube 26 is fixed.

An optical system support cylinder 13 is provided in the center of the tip forming portion 3 so as to penetrate the both block bodies 18 and 21 and to straddle the both block bodies 18 and 21. Objective lenses l _{1 to} l ₄ are fitted to the front part of the lens, and a tip end image receiving part of an image guide fiber 22 which is an optical image transmitting means is fitted to the rear part of the lens.

That is, in the front part inside the support tube 13, the outermost surface lens l ₁ and the lens l ₂ cemented thereto are directly attached to the support tube 13 and the lens.
L ₃ and l ₄ are held by the lens support frame 14 and fixed to the support cylinder 13, and the tip end image receiving portion of the image guide fiber 22 in which the image receiving surface 22a is arranged at the image forming position of the objective lenses l _{1 to} l ₄ is supported. Cylinder
It is fixed to the rear of 13.

If the observation optical system is configured in this way, the objective lens l ₁ ~
The optical axis is not displaced between l ₄ and the image receiving surface of the image guide fiber 22, and vignetting and aberration around the visual field are not generated.

Here, the support cylinder 13 is fitted into the fitting hole 21a formed by the through hole of the rear block body 21, and is positioned by the block body 21. The front block body 18 is provided with a through hole 18a corresponding to the support cylinder 13, and the tip end of the support cylinder 13 is loosely fitted with a slight gap. This is because the front and rear block bodies 18 and 21 are positioned with respect to each other in the vicinity of their outer peripheral surfaces, so if there is no gap in the through holes of both the front and rear block bodies, the support cylinder 13 will be broken due to dimensional error. This is because they will not fit in both blocks.

Further, the air / water feeding nozzle 6 is also fitted above the observation optical system so as to straddle both block bodies 18 and 21, and the rear end opening is fitted into the block body 21 having a rear part. It communicates with the fixed connection pipe 15. An air / water feeding tube 16 is connected to the connection pipe 15. Further, in the air supply / water supply passage opposite to the observation optical system, through holes 7 and 17 for inserting the both block bodies 18 and 21 are formed, and the tip end of the air passage is formed. Front block body
The through hole formed in 18 constitutes the channel opening 7. Then, the through hole 17 of the rear block 21
A connecting pipe 25 is fitted to the pipe 25, and a flexible tube 24 for forceps channel is connected to the pipe 25.
24, connecting pipe 25 and through hole 17 with forceps channel 23
Is composed.

In FIG. 1, the notch 21b is provided in the portion of the block body 21 having the rear part having the connecting pipe 25 inserted therein for connecting the flexible tube 24 by the length of the notch. The connection length can be shortened without reducing the connection strength with the pipe 25, and the rigid length of the distal end of the endoscope can be shortened.

[Effects of the Invention] As described above, according to the present invention, the lens holding frame holding the objective lens and the image receiving portion of the optical image transmitting member are fitted in the same support tube, so that the central light of both is The axes are automatically matched. Therefore, the periphery of the observation visual field is not eclipsed, aberration is not generated, and it is not necessary to adjust the centers of the both, and an observation optical system for an endoscope is provided which eliminates the conventional drawbacks of this kind. be able to.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of an essential part of an observation optical system of an endoscope showing an embodiment of the present invention, and FIG. 2 is a perspective view of an endoscope to which the present invention is applied. l _{1 to} l ₄ …… Objective lens 3 …… End part 13 …… Support tube 18 …… Front block 18a …… Through hole 21 …… Rear block 21a …… Mating hole

Claims (1)

[Claims] 1. An endoscope comprising an objective lens system and an image receiving section for receiving an image from the objective lens system in a tip forming section, wherein all the lenses forming the objective lens system and a support for supporting the image receiving section. While providing a cylinder, the above-mentioned tip constituent part,
It is divided into a front block and a rear block, a fitting hole for fitting and supporting the support cylinder is provided in the rear block, and a through hole for loosely fitting the support cylinder is provided in the front block. An endoscope characterized in that the support cylinder is arranged so as to straddle a hole.