JP5551571B2 - End structure of endoscope insertion part - Google Patents

Description

  The present invention relates to a distal end structure of an endoscope insertion portion in which a light guide that transmits illumination light is incorporated.

  As is well known, endoscopes widely used in the medical field have an elongated insertion portion that is inserted into a subject.

  For example, as disclosed in the endoscope of Patent Document 1, this insertion portion incorporates various components such as an imaging device, an imaging optical system, an illumination optical system, and various channels at a distal end portion with the increase in functionality. Has been. The conventional endoscope includes three illumination windows so as to surround the observation window.

JP 2005-192638 A

  By the way, while a built-in thing to an insertion part and a front-end | tip part increases like the conventional endoscope, the insertion part and front-end | tip part of an endoscope are hoped for diameter reduction for a patient's burden reduction. .

  In addition, as in the endoscope of Patent Document 1, a configuration in which three illumination windows are provided and a light guide that transmits illumination light to these illumination windows is branched into three on the distal end side is a built-in configuration. Since there are many elements, an insertion part and a front-end | tip part will become a large diameter. In other words, an endoscope configured to branch the light guide into three on the distal end side as in the past requires a space for fixing and arranging various components incorporated in the distal end portion of the insertion portion. Only the large diameter insertion part and the tip part were employed.

  For example, as shown in FIGS. 12 to 15, the distal end portion 101 of the endoscope having a specific conventional structure has an observation window 102, three illumination windows 103, a treatment instrument channel opening 104, and a washing nozzle 105 on the distal end surface. And a forward water channel opening 106 is provided.

  As shown in FIGS. 13 and 15, in the distal end portion 101 of the endoscope, an imaging device (imaging unit) 110, three light guide bundles 111 that transmit illumination light around the imaging device 110, The treatment instrument channel 112, the air / water supply channel 113, the forward water supply channel 114, and at least four components are included. When the three light guide bundles 111 are included, a total of seven built-in objects are arranged. In the drawings based on this conventional structure, the X direction in the figure is horizontal (left and right), the Y direction is vertical (up and down), and the up and down direction (direction along the Y direction) as viewed toward the paper surface is the inner side. This corresponds to the vertical direction of an image (captured image, monitor display image) captured by the endoscope.

  By the way, the distal end portion 101 of the endoscope shown in FIG. 13 has a line A1 connecting the center of the imaging unit 110 (center of the observation window 102) and the center of the lowermost light guide bundle 111 (center of the illumination window 103). At the boundary, the treatment instrument channel 112 and the air / water supply channel 113 are arranged on the left side along the X direction in the figure, and the front water supply channel 114 is arranged on the right side along the X direction in the figure. ing.

  On the other hand, the distal end portion 101 of the endoscope shown in FIG. 15 has a line A2 connecting the center of the imaging unit 110 (center of the observation window 102) and the center of the lowermost light guide bundle 111 (center of the illumination window 103). At the boundary, the treatment instrument channel 112 and the forward water supply channel 114 are disposed on the left side along the X direction in the figure, and the air / water supply channel 113 is disposed on the right side along the X direction in the figure. ing.

  Even in such a conventional multifunctional endoscope, there is a demand for reducing the diameter of the insertion portion and the distal end portion in order to reduce the burden on the patient. However, in the distal end structure of the insertion portion of the multifunction endoscope having three illumination windows as in Patent Document 1, the assembly of various built-in portions is deteriorated. It was difficult to reduce the diameter.

  Therefore, the present invention has been made in view of the above circumstances, and it is possible to reduce the diameter of the endoscope insertion portion and the distal end portion, and also to prevent deterioration in assembling properties of various components incorporated in the distal end portion. It aims at providing the tip part structure of an endoscope insertion part.

The distal end structure of the endoscope insertion portion according to one aspect of the present invention includes an imaging unit built in the distal end portion of the endoscope, and a first branch that branches into three around the imaging unit and transmits illumination light . A distal end structure of an endoscope insertion portion including a third light guide bundle and a treatment instrument channel, an air / water supply channel, and a forward water supply channel disposed in the distal end portion. Among the first to third light guide bundles branched into two, the center of the third light guide bundle located at the lowest position in the vertical direction of the image taken by the imaging unit and the center of the imaging unit are connected. the treatment instrument channel is arranged below the second region of the two regions line divided by a line, the air and water supply channel and the forward water Chang in a first region of the two regions With arranging the Le, outward away from the center of said air and water supply channels and the second or the imaging unit than the third one of the lines connecting respectively the center of the forward water-feeding channel of the treatment instrument channel The center of the third light guide bundle located at the lowermost position is arranged on the side, and the first and second light guide bundles of the three light guide bundles are respectively connected to the first region and the second light guide bundle. The linear distance L3 from the center of the imaging unit to the center of the third light guide bundle is arranged above the area of the imaging unit and substantially opposite to each other about the first line. wherein the center of the straight line distance L1 and the imaging unit to the center of the first light guide bundle located in the most upward from the center second Longer than the linear distance L2 to the center of the light guide bundle, the straight line distance L1, L2 is set to be the same or substantially the same.

  The distal end structure of the endoscope insertion portion according to the present invention can reduce the diameter of the endoscope insertion portion and the distal end portion, and can also prevent deterioration in assembling properties of various components incorporated in the distal end portion. effective.

The perspective view which concerns on the 1st Embodiment of this invention and shows the whole structure of an endoscope system. The top view which shows the structure of the front-end | tip part of an insertion part similarly FIG. 2 is a cross-sectional view taken along line III-III in FIG. The perspective view which shows the structure of the protection member which protects a light guide bundle similarly 3 is a cross-sectional view taken along line VV in FIG. 3 showing the internal configuration of the tip portion. Schematic diagram for explaining the layout of the internal configuration of the tip portion The top view which shows the structure of the front-end | tip part of the insertion part of a modification same as the above FIG. 7 is a cross-sectional view taken along line VIII-VIII in FIG. 7, showing the internal configuration of the tip of the modification. FIG. 8 is a sectional view taken along line IX-IX in FIG. The exploded perspective view showing the configuration of the tip cover XI-XI line sectional view of FIG. Plan view showing an example configuration of a distal end portion of the insertion portion of the traditional Sectional view showing the internal structure of the end portion of FIG. 12 Plan view showing an example configuration of a distal end portion of the insertion portion of the traditional Sectional view showing the internal structure of the end portion of FIG. 14

  Hereinafter, the distal end structure of the endoscope insertion portion according to the present invention will be described. In the following description, the drawings based on the following embodiments are schematic, and the relationship between the thickness and width of each part, the thickness ratio of each part, and the like are different from the actual ones. It should be noted that there are cases in which parts having different dimensional relationships and ratios are included in the drawings.

  First, an embodiment of the distal end structure of the endoscope insertion portion of the present invention will be described with reference to the drawings. 1 to 11 relate to an embodiment of the present invention, FIG. 1 is a perspective view showing the overall configuration of the endoscope system, FIG. 2 is a plan view showing the configuration of the distal end portion of the insertion portion, and FIG. 2 is a cross-sectional view taken along the line III-III, FIG. 4 is a perspective view showing the structure of the protective member protecting the light guide bundle, FIG. 5 is a cross-sectional view taken along the line V-V in FIG. 7 is a schematic diagram for explaining the layout of the internal configuration of the distal end portion, FIG. 7 is a plan view showing the configuration of the distal end portion of the insertion portion of the modification, and FIG. 8 shows the internal configuration of the distal end portion of the modification. 9 is a cross-sectional view taken along line VIII-VIII, FIG. 9 is a cross-sectional view taken along line IX-IX of FIG. 8, FIG. 10 is an exploded perspective view showing the structure of the front end cover, and FIG. It is the XI-XI sectional view taken on the line. In the drawings based on the present embodiment, the X direction in the drawing is horizontal (left and right), the Y direction is vertical (up and down), and the up and down direction (up and down direction along the Y direction) viewed toward the page is The image coincides with the vertical direction of the image (monitor display image) taken by the endoscope.

The endoscope system 1 shown in FIG. 1 includes an endoscope 2, a light source device 5, a video processor 6 is a CCU (camera control unit), the monitor 7, is configured that the main part has a Yes.

  As shown in the drawing, the endoscope 2 includes an insertion portion 11 as an elongated hollow elongated member to be inserted into an observation target site, and an operation portion 12 connected to the proximal end portion of the insertion portion 11. The universal cable 13 extended from the side surface of the operation unit 12, the light source connector 14 provided at the extended end of the universal cable 13, and the electric cable 15 extending from the side of the light source connector 14 And an electrical connector 16 disposed at the extending end of the electrical cable 15. The light source connector 14 is detachably connected to the light source device 5. The electrical connector 16 is detachably connected to the video processor 6.

The insertion portion 11 has a tip 21 on the distal end side, a bending portion 22 as lifting the movable portion curved is provided continuously to a rear portion of the distal end portion 21. Further, a long and flexible flexible tube portion 23 formed of a soft tubular member is connected to the rear portion of the curved portion 22.

  The operation unit 12 is arranged in the vicinity of the operation unit main body 20 constituting the operation gripping unit, the folding unit 24 connected to the proximal end side of the flexible tube unit 23 of the insertion unit 11, and the folding unit 24. And a treatment instrument insertion port 25 serving as an opening of the insertion channel in the insertion portion 11.

  The operation unit body 20 is provided with a bending operation knob 26 for bending the bending portion 22 of the insertion unit 11 and is provided with switches 28 and 29 for various endoscope functions. ing. The bending operation knob 26 includes a UD bending operation knob 26a for bending the bending portion 22 in the vertical direction, and an RL bending operation knob 26b for bending the bending portion 22 in the left-right direction. Are superimposed. In addition, a release knob 27 that is operated when stopping / releasing the rotation of each of the bending operation knobs 26a and 26b is provided at the center of the RL bending operation knob 26b.

  The light source device 5 supplies illumination light to the light guide (not shown) provided in the endoscope 2. That is, a light guide, which will be described later, is disposed in the universal cable 13, the operation unit 12, and the insertion unit 11 of the endoscope 2 according to the present embodiment, and the light source device 5 is provided via the light guide. Illumination light is supplied to an illumination optical system, which will be described later, constituting the illumination window of the distal end portion 21. This illumination light diverges by the illumination optical system and irradiates the test site.

  The video processor 6 converts the image data captured by the endoscope 2 into a video signal and displays it on the monitor 7. Further, the video processor 6 receives operation signals from the switches 29 disposed in the operation unit 12 of the endoscope 2, and controls the light source device 5 or drives a compressor (not shown) based on these signals. Or air is sent to a water supply tank (not shown) to supply air or water that is cleaning water in the water supply tank, physiological saline, or the like to the distal end portion 21 via the air supply / water supply channel of the insertion portion 11. A device for controlling water supply is also configured. The switches 28 are mechanical switches that are operated by the user during air / water feeding.

  As shown in FIG. 2, the distal end surface of the distal end portion 21 serves as a plurality of (herein, three to three illumination optical systems) first to third illumination windows 31 a to 31 c and a suction conduit opening, and a treatment instrument or the like. The treatment instrument channel opening 32 from which the water is derived, the forward water supply channel opening 33, the observation window 34 which is an objective optical system, and a liquid or gas (and further, a gas-liquid mixed fluid) is directed toward the surface of the observation window 34. An endoscope cleaning nozzle (hereinafter simply referred to as a cleaning nozzle) 41 that ejects is disposed. The first to third illumination windows 31 a to 31 c are arranged so as to surround the observation window 34.

  As shown in FIG. 3, the distal end portion 21 includes a distal-end component body 40 of a metal block. A tip cover 30 made of resin is placed on the tip surface side of the tip component body 40.

  In the distal end portion 21, an objective lens unit 38 is configured by juxtaposing an objective lens group 39 that is a plurality of objective optical systems respectively held by a plurality of lens holding frames to be fitted behind the observation window 34. ing. An imaging unit 37 that is an image sensor provided with a solid-state imaging device 37a such as a CCD or CMOS is fitted behind the objective lens unit 38.

  The objective lens unit 38 has a distal end portion inserted into the distal end component main body 40 and is fixed by a screw or the like (not shown). Then, an adhesive or the like is applied around the image pickup unit 37, and the objective lens unit 38 and the image pickup unit 37 are fixed to the tip component body 40.

  Also, each of the first to third illumination windows 31a to 31c is provided with each of the first to third illumination lens holding frames 54a to 54c (the second illumination lens holding frame 54b is not shown in FIG. 3). ) Is held and fixed at the tip.

  In the present embodiment, the first to third illumination lens holding frames 54a to 54c are provided with the first to third light guide holding tubes 51a to 51c (in FIG. 3, the second light guide holding frame) from the rear. A tube 51b (not shown) is inserted. The first to third light guide holding tubes 51a to 51c have first to third light guide bundles 50a to 50c having substantially the same diameter (see FIG. 4 and FIG. 5; FIG. 3). The second light guide bundle 50b (not shown) is inserted and focused. The first to third light guide holding pipes 51a to 51c are also inserted into the tip structure portion main body 40 and fixed by screws or the like (not shown), and the tip structure is formed by applying an adhesive or the like around them. It is fixed to the body 40.

  Each of the first to third light guide bundles 50a to 50c is converged by coating thin film tubes 53a to 53c on portions extending rearward from the first to third light guide holding tubes 51a to 51c. (See FIGS. 4 and 5). Each of the first to third light guide bundles 50a to 50c converged by these thin-film tubes 53a to 53c is inserted into the respective protection tubes 52 in the bending portion 22 that can be bent.

  As shown in FIGS. 3 and 4, each protection tube 52 has a tapered portion 54 that is scraped off so that the tip end portion is tapered from one outer peripheral portion. The tapered portion 54 is formed so as not to interfere with various components of the distal end portion 21 (hereinafter sometimes simply referred to as a built-in object). At least in the distal end portion 21 that is not movable like the bending portion 22, the protective tube 52 covers half of the first to third light guide bundles 50 a to 50 c in the cross-sectional direction, so that the first to first 3 light guide bundles 50a to 50c are sufficiently protected.

  And as for these protection tubes 52, each front-end | tip part covers the base end part of the 1st-3rd light guide holding pipes 51a-51c, and each front-end | tip part is the 1st-3rd light guide holding pipe by the bobbin 52a. It is being fixed to the base end peripheral part of 51a-51c. These protective tubes 52 are disposed at least in the range of the bending portion 22 so that excessive load is not generated and damaged in the first to third light guide bundles 50a to 50c due to the bending of the bending portion 22.

  Further, three metal pipes 61, 63, 65 (see FIG. 5) are inserted and fixed to the tip component main body 40 by screws or the like, and an adhesive or the like is applied and fixed around them. ing. The three metal pipes 61, 63, 65 are respectively connected to a treatment instrument channel 62, an air / water supply channel 64, and a front water supply channel 66 of a flexible tube that is inserted into the insertion portion 11.

  That is, in the metal pipe 61 to which the treatment instrument channel 62 is connected, the distal end opening constitutes the treatment instrument channel opening 32 shown in FIG. The metal pipe 63 to which the air / water supply channel 64 is connected is communicated with the cleaning nozzle 41 by being inserted and fixed to the tip component body 40. Further, the metal pipe 65 to which the front water supply channel 66 is connected has a front end opening that forms the front water supply channel opening 33 shown in FIG.

  Regarding the structure of the distal end portion 21 of the endoscope 2 configured as described above, the arrangement layout of various components (built-in items) accommodated in the distal end portion 21 will be described in detail below based on FIG. To do.

  As shown in FIG. 6, in the present embodiment, in the distal end portion 21, the center O1 of the imaging unit 37 (the center of the imaging elephant and the extension of the imaging optical axis O1 passing through the center of the observation window 34 in FIG. 3). And includes the extension line of the illumination optical axis O4 passing through the center of the third illumination window 31c in FIG. 3. The arrangement positions of the treatment instrument channel 62, the air / water supply channel 64, and the forward water supply channel 66 are divided by a line A connecting them with the same reference numerals). That is, here, only the treatment instrument channel 62 is disposed in the right region bordered by the line A, and the air / water feed channel 64 and the forward water feed channel 66 are disposed in the left region bordered by the line A. ing.

  Then, on the outer side (outer peripheral side) of the distal end portion 21 from the lines B and C connecting the center O5 of the treatment instrument channel 62, the center O6 of the air / water supply channel 64 and the center O7 of the front water supply channel 66, respectively. The center O4 of the third light guide bundle 50c is located. In other words, the third light guide bundle 50c is located on the outer peripheral side in the tip end portion 21 in this case, so that the center O4 is further away from the center O1 of the imaging unit 37 than the lines B and C. It is disposed so as to be inserted into the distal end portion 21.

  Further, the linear distance L3 from the center O1 of the imaging unit 37 to the center O4 of the third light guide bundle 50c is from the center O1 of the imaging unit 37 to the uppermost position of the first light guide bundle 50a here. From the straight line distance L1 to the center O2 (in FIG. 3, including the extension line of the illumination optical axis O2 that passes through the center of the first illumination window 31a and indicated by the same symbol) and the center O1 of the imaging unit 37, here in the middle of the vertical direction It is longer than the straight line distance L2 to the center O3 of the second light guide bundle 50b positioned at. The linear distances L1 and L2 are set to be the same (L1 = L2) or substantially the same (L1≈L2).

  The treatment instrument channel 62 also serving as an aspiration channel is lower than the imaging unit 37 (the imaging unit 37 in the figure) because of the visibility of the treatment of the affected part by the derived treatment instrument and the visibility when sucking mucous membranes, blood, and the like in the body. It is preferable to be positioned below the LR broken line passing through the center O1. Further, the treatment instrument channel 62 and the front water supply channel 66 are located in a region where the centers O5 and O7 are divided into left and right with a UD broken line in the drawing connecting the vertical direction passing through the center O1 of the imaging unit 37 as a boundary. It is preferable to arrange so as to. This is because, when water is fed forward in a state in which the treatment tool is led out from the treatment tool channel 62, the treatment tool and the front are separated from the same side divided into left and right with the center of the endoscope image taken by the imaging unit 37 as a boundary. This is because water supply is displayed as an image, and it becomes difficult for the user to perform treatment and water supply to the affected area.

As described above, in the layout configuration of various components inside the distal end portion 21 in the insertion portion 11 of the endoscope 2 of the present embodiment, first, as shown in FIG. And a treatment instrument channel 62 which is the thickest channel among the various channels in a region divided into left and right with a line A connecting the center O4 of the third light guide bundle 50c positioned at the lowermost position as a boundary. The air / water supply channel 64 and the forward water supply channel 66 which are channels smaller in diameter than the treatment instrument channel 62 are arranged. As described above, the center O4 of the third light guide bundle 50c located at the lowermost position among the first to third light guide bundles 50a to 50c is closer to the imaging unit 37 than the lines B and C. It is located on the outer peripheral side so as to be away from the center O1.

  In accordance with this, the first to third illumination windows 31a to 31c are located on the distal end surface of the distal end portion 21 (the distal end cover 30) shown in FIG. 2 rather than the first and second illumination windows 31a and 31b. The third illumination window 31c is disposed at a position slightly away from the observation window 34. Such a configuration is effective in reducing the diameter of the tip 21 by optimizing the arrangement positions of various components according to other built-in objects disposed in the tip 21.

In such an internal structure of the distal end portion 21 of the insertion portion 11, various components can be effectively arranged in a space restricted in the cross-sectional direction of the distal end portion 21, and therefore the insertion portion 11 and the distal end portion 21. The diameter can be reduced. Even if the insertion portion 11 and the distal end portion 21 are reduced in diameter, the treatment instrument channel 62 that is the largest diameter channel in the separate areas with the line A as a boundary , the small-diameter air / water supply channel 64, and the front The water supply channel 66 is arranged separately, and the layout configuration is such that the center O4 of the third light guide bundle 50c is positioned on the outer peripheral side so as to be farther from the center O1 of the imaging unit 37 than the lines B and C. In addition, it is possible to secure a space necessary for assembling various components in the cross-sectional direction of the tip component main body 40. Therefore, the imaging unit 37, the objective lens unit 38, the metal pipes 61, 63, 65, the first to third illumination lens holding frames 54a to 54c, and the first to third lights in advance to the distal end component main body 40. It is possible to prevent the assembly of the first to third light guide holding tubes 51a to 51c through which the guide bundles 50a to 50c are inserted from being lowered. In addition, the treatment instrument channel 62, the air / water supply channel 64, and the front water supply channel 66 can be easily connected to the metal pipes 61, 63, 65, and further to the first to third light guide bundles 50a to 50c. The protective tube 52 can be easily attached.

The internal configuration of the distal end portion 21 may be as shown in FIGS .
Specifically, the first and second illumination lens holding frames 54a and 54b are connected to the first and second light guide holding tubes 51a and 51b from the rear (the second light guide holding tube in FIG. 8). 51b (not shown) is inserted. Note that the first and second light guide holding tubes 51a and 51b have substantially the same diameter and the first and second light guide bundles 50a and 50b (see FIG. 9; see FIG. 8). The second light guide bundle 50b (not shown) is inserted and focused. The first and second light guide holding pipes 51a and 51b are also inserted into the tip component main body 40 and fixed by screws or the like (not shown), and an adhesive or the like is applied to the periphery thereof to configure the tip. It is fixed to the body 40.

  The third illumination lens holding frame 54c internally holds an illumination lens group 46 that is a plurality of illumination optical systems disposed behind the third illumination window 31c. The front end surface of the third light guide bundle 50c having the largest amount of illumination light transmitted as a larger diameter than the first and second light guide bundles 50a and 50b on the most proximal end of the illumination lens group 46. The third light guide holding tube 51c through which the third light guide bundle 50c is inserted and converged is inserted into the distal end component main body 40 so as to hit. The third light guide holding tube 51c is also inserted into the tip component body 40 and fixed by screws or the like (not shown), and an adhesive or the like is applied to the periphery of the third light guide holding tube 51c to the tip component body 40. It is fixed.

  In these first to third light guide bundles 50a to 50c, it is only necessary that the total amount of illumination light transmitted by each of the light guide bundles 50a to 50c is a necessary amount of illumination to be captured by the imaging unit 37 of the endoscope 2. Therefore, in the present embodiment, the first and second light guide bundles 50a and 50b have a small diameter and the third light guide bundle 50c has the first and second diameters according to the built-in object of the tip portion 21. The diameter is larger than that of the light guide bundles 50a and 50b.

  Accordingly, the first to third illumination windows 31a to 31c have the diameters of the first and second illumination windows 31a and 31b on the tip surface of the tip portion 21 (tip cover 30) shown in FIG. The third illumination window 31c is small and is disposed at a position close to the observation window 34. The third illumination window 31c is larger in diameter than the first and second illumination windows 31a and 31b, and is disposed at a position slightly away from the observation window 34. ing. In such a configuration, the diameters and arrangement positions of the first to third light guide bundles 50a to 50c are optimized according to other built-in objects arranged in the tip portion 21, and the tip portion 21 is effective for reducing the diameter.

  As shown in FIGS. 8 and 9, of the three protective tubes 52, the tapered portion 54 of the protective tube 52 through which the first light guide bundle 50a is inserted faces the outside of the distal end portion 21 here. The tapered portion 54 of the protective tube 52 through which the second and third light guide bundles 50 b and 50 c are inserted is arranged so as to face the inside of the tip end portion 21. This is because the distal end side of the imaging unit 37 has a larger diameter than the proximal end side, and therefore the first light guide bundle in the present embodiment according to the layout of the built-in objects disposed in the distal end portion 21. The taper portion 54 of the protective tube 52 that protects 50a is disposed so as to face the outside of the distal end portion 21.

  That is, each protective tube 52 is arranged so as to face a direction not interfering with the built-in object in accordance with the shape of the built-in object at the distal end portion 21 because there is no thick portion where the tapered portion 54 is formed. Therefore, here, only the protective tube 52 that protects the first light guide bundle 50a is configured such that the tapered portion 54 faces the outside of the distal end portion 21. The tapered portion 54 of the tube 52 may be disposed so as to face the outside of the distal end portion 21 or each direction around the longitudinal axis so as not to interfere with the built-in object. Accordingly, the diameter of the tip 21 is reduced by appropriately defining the direction around the longitudinal axis of each protective tube 52 so that the taper 54 does not interfere with the built-in object in accordance with the space in the tip 21. It is possible to make the configuration effective.

  By the way, as shown in FIG. 10, the tip end portion 21 of the present embodiment covers the tip end side of the tip constituent portion main body 40 with a resin tip cover 30.

  As shown in FIG. 11, the distal-end component body 40 includes an outer peripheral side thick portion 40 a where the first light guide bundle 50 a is disposed and an outer peripheral side portion where the treatment instrument channel 62 is disposed. A gentle convex shape is formed so that the two portions of the thick portion 40b rise upward. The tip component main body 40 has such an outer shape that is not a perfect circle in cross section, but an irregular shape, and a wall thickness dimension required to prevent a cut during formation of a fitting hole through which various components are inserted. And the distal end portion 21 has a small diameter by reducing the circumference of the first light guide bundle 50a and the treatment instrument channel 62 around the outer periphery as the thick portions 40a and 40b having the necessary thickness. It becomes.

  Further, the tip cover 30 to be mounted on the tip component body 40 has an inner peripheral surface formed in accordance with the outer peripheral surface shape of the tip component body 40. In other words, the inner peripheral portion of the tip cover 30 is formed with a gentle concave shape at two locations where it fits in accordance with the convex shape of each of the thick portions 40a and 40b of the tip component main body 40. As a result, the direction of assembling the tip cover 30 to the tip component main body 40 is determined, and can be easily assembled, bonded, and screw-fixed without rotating.

  In addition, the tip cover 30 secures a certain amount of thickness at a portion (a range P1 in the drawing) fitted to the thick portion 40a in order to buffer the impact and prevent damage to the first light guide bundle 50a. The shape is raised on the outer peripheral side. On the other hand, it is preferable that the tip cover 30 has a perfect circular section from the viewpoint of insertion into the body, and the inner peripheral portion that fits into the thick portion 40b is formed with a gentle recess 30a, and the thickness of the portion is increased. d is formed thinly. By doing in this way, the tip cover 30 has an irregular shape that is bulged outward only in the portion that fits into the thick portion 40a, and at least the other range (P2 in the figure) due to the thinned thickness d. The range is a perfect circle.

  As described above, the distal end structure of the endoscope insertion portion has a reduced diameter of the insertion portion 11 and the distal end portion 21 of the endoscope 2 and can be assembled with various components incorporated in the distal end portion 21. Can also be prevented. In the above description, the illumination windows 31a to 31c have three configurations. However, the present invention is not limited to this, and any number of illumination windows 31a to 31c may be used as long as there are a plurality of illumination windows. Just increase the number.

  The invention described in the above embodiment is not limited to the embodiment, and various modifications can be made without departing from the spirit of the invention in the implementation stage. Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements.

  For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, if the stated problem can be solved and the stated effect can be obtained, this constituent requirement is deleted. The structure can be extracted as an invention.

DESCRIPTION OF SYMBOLS 1 ... Endoscope system 2 ... Endoscope 7 ... Monitor 11 ... Insertion part 21 ... Tip part 22 ... Bending part 23 ... Flexible pipe part 26 ... Bending operation knob 30 ... End cover 31a ... 1st illumination window 31b ... Second illumination window 31c ... Third illumination window 32 ... Treatment instrument channel opening 33 ... Forward water supply channel opening 34 ... Observation window 37 ... Imaging unit 37a ... Solid-state imaging device 38 ... Objective lens unit 39 ... Objective lens group 40 ... Tip Constituent body 41 ... endoscope cleaning nozzle 46 ... illumination lens group 50a ... first light guide bundle 50b ... second light guide bundle 50c ... third light guide bundle 51a ... first light guide holding tube 51b ... second light guide holding tube 51c ... third light guide holding tube 52 ... protection tube 52a ... pincushion 54 ... tapered portion 54a ... first illumination lens holding frame 54 ... second illumination lens holding frame 54c ... third illumination lens holding frame 61, 63, 65 ... metal pipe 62 ... treatment instrument channel 64 ... air and water supply channel 66 ... forward water-feeding channel O1～O7 ... center of

Claims (5)

An imaging unit built in the distal end portion of the endoscope, and first to third light guide bundles that are branched into three around the imaging unit and transmit illumination light, are provided in the distal end portion. A distal end structure of an endoscope insertion portion in which a treatment instrument channel, an air supply / water supply channel, and a front water supply channel are disposed ,
Of the first to third light guide bundles branched into the three, the center of the third light guide bundle located at the lowest position in the vertical direction of the image taken by the imaging unit, and the center of the imaging unit The treatment instrument channel is disposed below the second region of the two regions divided by the first line connecting the two, and the air / water supply channel and the front water supply channel are disposed in the first region of the two regions. And at the outer side away from the center of the imaging unit than either the second or third line connecting the center of the treatment instrument channel and the centers of the air / water supply channel and the forward water supply channel, respectively . The center of the third light guide bundle located at the lowest position is arranged,
Of the three light guide bundles, the first and second light guide bundles are arranged above the first region and the second region, respectively, at positions substantially opposite to each other with the first line as a center. and, the linear distance from the center of the imaging unit to the center of the third light guide bundle L3 is linear distance L1 to the center of the first light guide bundle located in the most upward from the center of the imaging unit The linear distance from the center of the imaging unit to the center of the second light guide bundle is longer than the linear distance L2 , and the linear distances L1 and L2 are set to be the same or substantially the same. The tip structure of the endoscope insertion part. Of the three light guide bundles, the lowermost third light guide bundle has a larger diameter than the other first and second light guide bundles, and transmits the largest amount of illumination light. The distal end structure of the endoscope insertion portion according to claim 1. The distal end portion has two outer peripheral portions so that two thick portions on the outer peripheral side where the treatment instrument channel and one of the three light guide bundles are arranged have a predetermined thickness dimension. The cross section is formed in a convex shape,
The concave shape matched with the convex shape of the two places is formed in the tip cover fitted to the outer peripheral portion of the tip portion at two locations of the inner peripheral portion. End tip structure of the endoscope insertion part.   The distal end cover has a thickness of the concave shape that fits into the convex shape of the distal end portion where the treatment instrument channel is disposed, and at least the outer peripheral portion of the concave shape has a perfect circular cross section. The distal end structure of the endoscope insertion portion according to claim 3.   The endoscope insertion portion according to any one of claims 1 to 4, wherein the treatment instrument channel is disposed below the imaging unit in a vertical direction of an image captured by the imaging unit. Tip structure.