Endoscope

Abstract

The present invention provides an endoscope capable of preventing liquid in a liquid channel from being sucked up and ejected together with the gas during a gas supply operation. The endoscope of the present invention comprises a liquid channel (40) through which liquid passes and a gas channel (30) through which gas passes, and a confluence recess (134) where liquid and gas merge is formed at a front end portion (13), wherein one end side of the liquid channel (40) and one end side of the gas channel (30) are connected to the confluence recess (134), so that the size of a first communication hole (34) between the gas channel (30) and the confluence recess (134) is larger than the size of a second communication hole (44) between the liquid channel (40) and the confluence recess (134).

Description

Technical Field

[0001] The present invention relates to an endoscope having a converging recess formed at a distal end portion where liquid and gas merge.

[0002] This application claims the benefit of priority based on Japanese application No. 2020-167753, filed on October 2, 2020, and incorporates by reference all the disclosures disclosed in the Japanese application. Background Art

[0003] Conventionally, endoscopes having a gas channel and a liquid channel, the distal ends of which are connected to each other at a distal end portion of an insertion portion inserted into a body cavity, have been widely used.

[0004] For example, patent document 1 discloses an endoscope in which, in the connecting portion between the air supply line (gas channel) and the water supply line (liquid channel), the opening size of the air supply line is smaller than the opening size of the nozzle for spraying air or water, so that water will not flow back to the air supply line side when the water supply operation is performed, and water droplets can be prevented from being sprayed out together with air during the subsequent air supply operation.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2007-190118 Summary of the Invention

[0008] Problems to be solved by the invention

[0009] On the other hand, a confluence recess where liquid and gas converge is formed at the front end of the insertion portion, and the liquid or gas flows into the endoscope nozzle through the confluence recess. During the gas supply operation of only ejecting gas from the nozzle, due to the pressure difference between the confluence recess and the liquid channel, the liquid in the liquid channel may be sucked up and ejected from the nozzle together with the gas.

[0010] However, the endoscope of Patent Document 1 does not take such a problem into consideration and cannot solve the related problem.

[0011] The present invention has been developed in view of the above situation, and an object thereof is to provide an endoscope that can prevent the liquid in the liquid channel from being sucked up and ejected together with the gas during the gas supply operation.

[0012] Technical solutions to problems

[0013] The endoscope involved in the present invention has a liquid channel through which liquid passes and a gas channel through which gas passes, and a confluence recess where liquid and gas merge is formed at the front end, wherein one end side of the liquid channel and one end side of the gas channel are connected to the confluence recess, and the size of the first connecting hole between the gas channel and the confluence recess is larger than the size of the second connecting hole between the liquid channel and the confluence recess.

[0014] In the present invention, since the size of the first connecting hole between the gas channel and the confluence recess is larger than the size of the second connecting hole between the liquid channel and the confluence recess, when the gas supply operation of only spraying gas from the nozzle is implemented, the increase in air speed near the first connecting hole can be suppressed, thereby preventing the liquid in the liquid channel from being sucked up.

[0015] Effects of the Invention

[0016] According to the present invention, it is possible to prevent the liquid in the liquid channel from being sucked up and ejected together with the gas during the gas supply operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is an external view of the endoscope according to the first embodiment of the present invention.

[0018] Figure 2 It is a schematic diagram showing the distal end surface of the distal end portion of the endoscope.

[0019] Figure 3 It is a partial cross-sectional view illustrating the structure of the front end portion.

[0020] Figure 4 Yes Figure 3 An enlarged view showing a partial enlargement of the confluence recess in FIG.

[0021] Figure 5 It is along Figure 4 A cross-sectional view taken along line VV.

[0022] Figure 6 It is along Figure 4 Cross-sectional view taken along line VI-VI.

[0023] Figure 7 It is an explanatory diagram for explaining the communication state between the merging recess and the air supply connection portion.

[0024] Figure 8 The figures show simulation results of air flow when the first communicating hole and the second communicating hole are the same size and when the first communicating hole is larger than the second communicating hole.

[0025] Figure 9 This is an enlarged view showing a portion of the confluent recess of the endoscope according to the second embodiment.

[0026] Figure 10 This is an enlarged view showing a portion of the confluent recess of the endoscope according to the third embodiment. DETAILED DESCRIPTION

[0027] Hereinafter, an endoscope according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0028] (Implementation 1)

[0029] Figure 1 This is an external view of an endoscope 10 according to Embodiment 1 of the present invention. The endoscope 10 of this embodiment includes an insertion portion 14 having an imaging device and inserted into a body cavity of a subject; an operating portion 20 for operating the insertion portion 14; and a connector portion 24 for connecting to a processor, a light source, an air and water supply device, and the like (not shown).

[0030] The insertion portion 14 is connected to the operation portion 20 via the bend stop portion 16 , and the operation portion 20 is connected to the connector portion 24 via a universal cord 25 .

[0031] The universal cord 25 is flexible and includes an electric wire for transmitting an electric signal from the imaging device inserted into the portion 14 to the connector portion 24 , a water channel for circulating water fed from the connector portion 24 , and an air channel for circulating air.

[0032] The operation unit 20 includes a grip portion 205 , a button 201 for receiving instructions such as water supply or air supply from a user, and a bending knob 21 for operating the bending of the bending portion 12 described later.

[0033] The grip portion 205 is substantially cylindrical in shape and its diameter decreases toward the insertion portion 14. A channel entrance 22 for inserting a treatment tool or the like is provided on the grip portion 205 near the insertion portion 14.

[0034] The insertion portion 14 is in the shape of a thin cylindrical tube and is bendable. It includes, in order from one end on the front side, a distal end portion 13, a bending portion 12, and a flexible portion 11. The bending portion 12 bends as the bending knob 21 is operated.

[0035] The distal end portion 13 has a cylindrical shape and houses an imaging unit (not shown) including an imaging device such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor), an observation optical system, and the like.

[0036] Figure 2This is a schematic diagram showing the distal end surface 131 of the distal end portion 13 of the endoscope 10. The distal end surface 131 of the distal end portion 13 is circular. The distal end portion 13 is provided with an observation optical system 132, an air and water supply nozzle 140, a channel outlet 18, and an illumination optical system 133.

[0037] Two illumination optical systems 133 are spaced apart on the front face 131, with the observation optical system 132 disposed between the two illumination optical systems 133. Furthermore, an air and water supply nozzle 140 and the channel outlet 18 are disposed on the front face 131, spaced apart from the observation optical system 132. The air and water supply nozzle 140 sprays air or water toward the observation optical system 132, and the illumination optical system 133 emits illumination light to illuminate the subject.

[0038] Figure 3 It is a partial cross-sectional view illustrating the structure of the front end portion 13.

[0039] A confluence recess 134 where air and water sent from the operating unit 20 merge is formed on the front end surface 131 of the front end portion 13 , and the air and water supply nozzle 140 partially engages with the confluence recess 134 .

[0040] The confluence recess 134 has a circular cross-section and extends along the axial length of the front end portion 13. One end of the confluence recess 134, located near the front end surface 131 in the longitudinal direction, engages with the air and water supply nozzle 140. Furthermore, the other end of the confluence recess 134 communicates with the gas passage 30 and the liquid passage 40, described below.

[0041] The air and water supply nozzle 140 includes a cylindrical portion 143 with a circular cross-section and a cover 142 that covers one open end of the cylindrical portion 143. The cover 142 and the cylindrical portion 143 are integrally formed. The cylindrical portion 143 has an outer diameter slightly smaller than the inner diameter of the confluence recess 134, and the majority of the cylindrical portion 143 is embedded within the confluence recess 134. The cover 142 is disc-shaped and has a larger diameter than the outer diameter of the cylindrical portion 143. When the air and water supply nozzle 140 is engaged with the confluence recess 134, only the cover 142 is exposed at the front end surface 131.

[0042] The air and water supply nozzle 140 has an outlet 141 for ejecting air or water. The outlet 141 is substantially elliptical and opens toward the observation optical system 132. The outlet 141 is provided in the cylinder 143 on the cover 142 side.

[0043] As described above, the other end of the confluence recess 134 communicates with the gas channel 30 and the liquid channel 40. The gas channel 30 supplies gas (e.g., air) sent from the gas and water supply device to the gas and water supply nozzle 140. Furthermore, the liquid channel 40 supplies liquid (e.g., water) sent from the gas and water supply device to the gas and water supply nozzle 140.

[0044] The gas passage 30 includes a gas supply pipe 32 and a gas supply connection portion 31. The gas supply pipe 32 communicates with the other end of the confluence recess 134 via the gas supply connection portion 31. Furthermore, the gas supply pipe 32 extends longitudinally through the insertion portion 14 and is positioned so as to span the curved portion 12 and the distal end portion 13. Specifically, one end of the gas supply pipe 32 is connected to the gas supply connection portion 31, while the other end of the gas supply pipe 32 is connected to the gas and water supply device via the operating portion 20 and the connector portion 24.

[0045] Liquid passage 40 also includes a water supply pipe 42 and a water supply connection portion 41. Water supply pipe 42 communicates with the other end of confluence recess 134 via water supply connection portion 41. Furthermore, water supply pipe 42 extends longitudinally through insertion portion 14 and is positioned so as to span bend 12 and front end portion 13. Specifically, one end of water supply pipe 42 is connected to water supply connection portion 41, while the other end of water supply pipe 42 is connected to the air and water supply device via operating portion 20 and connector portion 24.

[0046] Figure 4 Yes Figure 3 An enlarged view showing a portion of the confluence recess 134 in FIG. Figure 5 It is along Figure 4 The cross-sectional view taken along line VV is Figure 6 It is along Figure 4 The cross-sectional view taken along line VI-VI is as follows: Figure 7 It is an explanatory diagram for explaining the communication state between the merging recess 134 and the air supply connection portion 31 . Figure 7 The outlines of the merging recess 134 and the air supply connection portion 31 are shown.

[0047] The air supply connection portion 31 has a generally cylindrical shape and delivers air flowing in from the air supply pipe 32 to the converging recess 134. The air supply connection portion 31 has a diameter equal to the inner diameter of the air supply pipe 32, and its upstream end is connected to the air supply pipe 32. Furthermore, a gas guide wall 33 is formed at the downstream end of the air supply connection portion 31 to guide air to the converging recess 134. The gas guide wall 33 is formed orthogonally to the axial length direction of the air supply connection portion 31.

[0048] A first communication hole 34 is formed at the communicating portion between the air supply connection portion 31 and the merging recess 134. The first communication hole 34 has a dimension L1 in the axial direction of the air supply connection portion 31 that is longer than a dimension L2 in a direction intersecting the axial direction of the air supply connection portion 31.

[0049] That is, the first communication hole 34 includes an orthogonal opening portion 341 (see FIG. 1 ) that opens in a direction orthogonal to the axial length direction of the air supply connection portion 31. Figure 5 and Figure 7 ) and a parallel opening portion 342 opened in a direction parallel to the axial length direction of the air supply connection portion 31 (see Figure 6 and Figure 7). The orthogonal opening 341 is wider than the parallel opening 342. That is, as described above, the dimension L1 of the first communication hole 34 is longer than the dimension L2, so the orthogonal opening 341 is wider than the parallel opening 342. The orthogonal opening 341 is Figure 5 The parallel opening 342 is a substantially rectangular area. Figure 6 The area in the middle that appears to be roughly convex lens (refer to Figure 6 thick line).

[0050] The water supply connection 41 has a generally cylindrical shape and delivers water flowing in from the water supply pipe 42 to the confluence recess 134. The water supply connection 41 has a diameter equal to the inner diameter of the water supply pipe 42, and its upstream end is connected to the water supply pipe 42. Furthermore, a liquid guide wall 43 is formed at the downstream end of the water supply connection 41 to guide water from the water supply pipe 42 into the confluence recess 134. The liquid guide wall 43 is formed perpendicular to the axial length of the water supply connection 41.

[0051] The second communication hole 44 is formed at the communicating portion between the water supply connection portion 41 and the confluence recess 134. That is, like the first communication hole 34, the second communication hole 44 includes an orthogonal opening portion (not shown) opening in a direction orthogonal to the axial length direction of the water supply connection portion 41 and a parallel opening portion 442 opening in a direction parallel to the axial length direction of the water supply connection portion 41 (see FIG. Figure 6 ). Like the first communicating hole 34, the orthogonal opening of the second communicating hole 44 is a substantially rectangular area, and the parallel opening 442 is a substantially convex lens area (refer to Figure 6 thick line).

[0052] The dimension L3 of the second communication hole 44 in the axial direction of the water supply connection part 41 is longer than the dimension L4 in the direction intersecting the axial direction of the water supply connection part 41. On the other hand, the dimension L3 of the second communication hole 44 in the axial direction of the water supply connection part 41 is shorter than the dimension L4 of the second communication hole 44 in the axial direction of the water supply connection part 41. Figure 4 ).

[0053] That is, the dimension L3 of the second communication hole 44 is shorter than the dimension L1 of the first communication hole 34 (see Figure 4 ), the size L4 of the second communicating hole 44 is substantially equal to the size L2 of the first communicating hole 34 (refer to Figure 4 and Figure 6 ).

[0054] Air delivered from the stop bend 16 side through the air supply pipe 32 flows into the merging recess 134 via the air supply connection 31. Water delivered through the water supply pipe 42 flows into the merging recess 134 via the water supply connection 41. The air and water then flow into the air and water supply nozzle 140 and are emitted toward the observation optical system 132 through the emission port 141.

[0055] On the other hand, when air is only ejected from the ejection port 141, a difference occurs between the air pressure near the first communication hole 34 and the air pressure within the water supply connection 41. Specifically, when only air is ejected from the ejection port 141, a difference occurs between the air pressure at position P1 near the first communication hole 34 and on the other side of the confluence recess 134, and the air pressure at position P2 near the surface of the remaining water within the water supply connection 41. This pressure difference causes the remaining water within the water supply connection 41 to be drawn up from the water delivery connection 41, contrary to the user's original intention, resulting in a small amount of water being ejected along with the air.

[0056] In contrast, in the endoscope 10 according to the first embodiment, as described above, the dimension L4 of the second communicating hole 44 is substantially equal to the dimension L2 of the first communicating hole 34, and the dimension L3 of the second communicating hole 44 is shorter than the dimension L1 of the first communicating hole 34. In other words, the size of the first communicating hole 34 is larger than the size of the second communicating hole 44.

[0057] Therefore, compared to a case where the first communicating hole 34 and the second communicating hole 44 are of equal size, an increase in the air flow velocity near the first communicating hole 34 can be suppressed, and the air flow becomes smoother, which can suppress the generation of eddies near the first communicating hole 34. Consequently, a decrease in air pressure near the first communicating hole 34, i.e., at position P1, can be suppressed.

[0058] Figure 8 The simulation results show the air flow when the first communication hole 34 and the second communication hole 44 are the same size and when the first communication hole 34 is larger than the second communication hole 44. Figure 8 A represents the existing endoscope, Figure 8 Reference numeral B shows the endoscope 10 according to the first embodiment.

[0059] In addition, Figure 8 In the figure, the direction of the arrow indicates the direction of air flow, the length of the arrow indicates the speed of the air, and the brightness and darkness also indicate the speed of the air.

[0060] from Figure 8 You can know, Figure 8 P1 position in B ( Figure 8 The length ratio of the arrow in the middle (○ part) Figure 8 A is short. That is, Figure 8 Compared with A, Figure 8 The air velocity at position P1 in B is suppressed.

[0061] As described above, in the endoscope 10 of the first embodiment, the air velocity at position P1 on the other end side of the confluence recess 134 can be suppressed, thereby suppressing the difference in air pressure between position P1 and position P2 near the surface of the remaining water in the water supply connection portion 41. Therefore, when performing an air supply operation in which only air is ejected from the ejection port 141, the problem of a small amount of water being ejected together with the air can be prevented.

[0062] Furthermore, in the endoscope 10 of the first embodiment, as described above, the dimension L1 of the first communication hole 34 is longer than the dimension L2, and the orthogonal opening 341 is wider than the parallel opening 342. Therefore, the proportion of air flowing into the merging recess 134 through the orthogonal opening 341 is greater than the proportion of air flowing into the merging recess 134 through the parallel opening 342.

[0063] Therefore, in Figure 8 In B, with Figure 8 Compared with A, the high-speed portion of the air flow, that is, the portion with a higher concentration, is offset further toward the second communication hole 44.

[0064] That is, in the endoscope 10 of the first embodiment, by deflecting the high-speed portion of the air flow toward the far side of the second communication hole 44 , a synergistic effect is achieved in suppressing the decrease in air pressure at the position P1 .

[0065] (Implementation Method 2)

[0066] Figure 9 This is an enlarged view showing a portion of the confluent recess 134 of the endoscope 10 according to the second embodiment.

[0067] The air supply connection portion 31 is generally cylindrical in shape, with its upstream end connected to the air supply pipe 32. Furthermore, a gas guide wall 33A is formed at the downstream end of the air supply connection portion 31 to guide air to the confluence recess 134. The gas guide wall 33A is formed at an angle relative to the axial length of the air supply connection portion 31, with the radial dimension of the air supply connection portion 31 gradually decreasing toward the downstream side.

[0068] The first communication hole 34 is formed at the communicating portion between the air supply connection portion 31 and the confluence recess 134. As in the first embodiment, the first communication hole 34 includes an orthogonal opening portion 341 (see FIG. 1 ) that opens in a direction orthogonal to the axial length direction of the air supply connection portion 31. Figure 5 and Figure 7 ) and a parallel opening portion 342 opened in a direction parallel to the axial length direction of the air supply connection portion 31 (see Figure 6 and Figure 7 ), the orthogonal opening 341 is wider than the parallel opening 342.

[0069] The water supply connection portion 41 is substantially cylindrical, and its upstream end is connected to the water supply pipe 42. Furthermore, a liquid guide wall 43 is formed at the downstream end of the water supply connection portion 41 to guide water to the confluence recess 134. The liquid guide wall 43 is formed perpendicular to the axial direction of the water supply connection portion 41.

[0070] The second communication hole 44 is formed at the communicating portion between the water supply connection portion 41 and the confluence recess 134. As in the first embodiment, the second communication hole 44 includes an orthogonal opening portion (not shown) opening in a direction perpendicular to the axial length direction of the water supply connection portion 41 and a parallel opening portion 442 opening in a direction parallel to the axial length direction of the water supply connection portion 41 (see FIG. Figure 6 ).

[0071] As described above, in the endoscope 10 of embodiment 2, the gas guide wall 33A for guiding the air from the gas supply pipe 32 into the confluence recess 134 is formed obliquely relative to the axial direction of the gas supply connection part 31, and the liquid guide wall 43 is formed orthogonally to the axial direction of the water supply connection part 41.

[0072] Therefore, the air does not change direction suddenly near the first connecting hole 34 and can flow smoothly. Therefore, the generation of eddy current can be suppressed, and the high-speed part of the air flow near the first connecting hole 34 can be shifted to the vicinity of the first connecting hole 34 farther from the second connecting hole 44. Figure 4 ) The flow of air is reduced, so the pressure difference between the P1 position and the P2 position can be suppressed, and when the air supply operation is implemented, the problem of a small amount of water being sprayed together with the air can be prevented.

[0073] Furthermore, in the second embodiment, the distance between the gas guide wall 33A and the liquid guide wall 43 (see Figure 9 The solid arrow in FIG) is greater than the distance between the gas guide wall 33A and the liquid guide wall 43 when the gas guide wall 33A is set to be perpendicular to the axial direction of the gas supply connection portion 31 (see FIG). Figure 9 Therefore, the high-speed portion of the air flow near the first communicating hole 34 becomes away from the water supply connection portion 41, and the remaining water in the water supply connection portion 41 is not easily affected by the above-mentioned air pressure difference.

[0074] The same parts as those in Embodiment 1 are denoted by the same reference numerals and detailed description thereof is omitted.

[0075] (Implementation 3)

[0076] Figure 10 This is an enlarged view showing a portion of the confluent recess 134 of the endoscope 10 according to the third embodiment.

[0077] The air supply connection portion 31 has a generally cylindrical shape, with its upstream end connected to the air supply pipe 32. Furthermore, a gas guide wall 33A is formed at the downstream end of the air supply connection portion 31 to guide air to the confluence recess 134. The gas guide wall 33A is formed to be inclined relative to the axial length direction of the air supply connection portion 31.

[0078] A first communication hole 34 is formed at a communicating portion between the air supply connection portion 31 and the merging recess 134. The shape of the first communication hole 34 is the same as that of the first embodiment, and detailed description thereof will be omitted.

[0079] The water supply connection portion 41 is substantially cylindrical, and its upstream end is connected to the water supply pipe 42. Furthermore, a liquid guide wall 43 is formed at the downstream end of the water supply connection portion 41 to guide water to the confluence recess 134. The liquid guide wall 43 is formed perpendicular to the axial direction of the water supply connection portion 41.

[0080] Furthermore, the water supply connection portion 41 has a diameter-reducing portion 41A formed in the middle portion in the axial direction, the diameter of which gradually decreases toward the downstream side. The upstream diameter of the diameter-reducing portion 41A is larger than the downstream diameter of the diameter-reducing portion 41A.

[0081] A second communication hole 44 is formed at a communicating portion between the water supply connection portion 41 and the merging recess 134. The shape of the second communication hole 44 is the same as that of the first embodiment, and detailed description thereof will be omitted.

[0082] As described above, in the endoscope 10 of the third embodiment, the water supply connection portion 41 is formed with a reduced diameter portion 41A, and the diameter of the reduced diameter portion 41A on the downstream side is smaller than the diameter on the upstream side. That is, since the diameter of the downstream side of the water supply connection portion 41 is reduced, the surface tension of the remaining water in the water supply connection portion 41 increases, and the remaining water in the water supply connection portion 41 is less likely to be affected by the position P1 and the position P2 (see Figure 4 Therefore, even if there is an air pressure difference between the P1 position and the P2 position, it is possible to suppress the remaining water in the water supply connection part 41 from being sucked up.

[0083] In the above description, the liquid guide wall 43 is formed perpendicular to the axial direction of the water supply connection portion 41. However, the present invention is not limited to this. For example, the liquid guide wall 43 may be formed obliquely relative to the axial direction of the water supply connection portion 41, similar to the gas guide wall 33A.

[0084] The same parts as those in Embodiment 1 are denoted by the same reference numerals and detailed description thereof is omitted.

[0085] The technical features (structural requirements) described in Embodiments 1 to 3 can be combined with each other, and new technical features can be formed by the combination.

[0086] It should be understood that the embodiments disclosed this time are illustrative in all aspects and not restrictive. The scope of the present invention is shown by the claims rather than the above meaning, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0087] Explanation of symbols

[0088] 10. Endoscope

[0089] 13 front end

[0090] 14 Insertion

[0091] 30 Gas Channel

[0092] 31 Gas supply connection

[0093] 33 Gas guide wall

[0094] 34 first communicating hole

[0095] 40 Liquid Channel

[0096] 41 Water supply connection

[0097] 41A Reduced diameter section

[0098] 43 Liquid guide wall

[0099] 44 second communication hole

[0100] 134 Confluence recess

[0101] 140 Air and water supply nozzles.

Claims

1. An endoscope having a liquid channel for passing liquid and a gas channel for passing gas, wherein a cylindrical confluence recess is formed at the front end portion where the liquid and gas merge, characterized in that: One end side of the liquid channel and one end side of the gas channel are connected to the confluent recess, The size of the first communication hole between the gas channel and the confluence recess is larger than the size of the second communication hole between the liquid channel and the confluence recess. The confluence recess has a circular bottom surface and opens at the front end surface of the front end portion. The first communicating hole and the second communicating hole are formed from the bottom surface to the side surface of the merging recess and are separated from each other in the radial direction of the bottom surface. A dimension of the first communicating hole from the bottom surface in the axial length direction of the merging recess is longer than a dimension of the second communicating hole from the bottom surface in the axial length direction of the merging recess.

2. The endoscope according to claim 1, wherein: In the first communication hole, a dimension in the axial direction of the gas channel is longer than a dimension in a direction intersecting the axial direction of the gas channel.

3. The endoscope according to claim 1 or 2, characterized in that In the gas passage, a gas guide wall is formed on the one end side to guide the gas to the first communication hole. The gas guide wall is formed to be inclined with respect to the axial direction of the gas passage.

4. The endoscope according to claim 1 or 2, characterized in that In the liquid channel, a liquid guide wall is formed on the one end side to guide the liquid to the second communication hole. The liquid guide wall is formed perpendicularly to the axial length direction of the liquid channel.

5. The endoscope according to claim 1 or 2, characterized in that The liquid channel has a cylindrical shape and has a reduced diameter portion on the one end side.

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