JP2012120701A - Endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the protrusion quantity of an observation window from the leading end of an insertion part and to enhance the washing properties and drainage properties of the observation window.SOLUTION: An air sending/water sending nozzle 22 and the observation window 28 are provided to the leading end part 16a provided to the leading end of the insertion part of an endoscope. The observation window 28 has the convex lens surface 34 protruded from a flat surface 27c and a jet orifice 38 is positioned on the first straight line Lconnecting the apex T of the convex lens surface 34 and the downstream end Ein the jet direction of a fluid in the convex lens surface 34 and the jet direction S when the fluid is jetted from the jet orifice 38 is arranged in parallel to the first straight line L. Further, the upper end 38a of the jet orifice 38 is positioned on the second straight line Lparallel to the first straight line Land coming into contact with the convex lens surface 34 at a contact point P and the lower end 38b of the jet orifice 38 is positioned on the third straight line Lparallel to the first straight line Land passing the upstream end Ein the jet direction of the fluid in the convex lens surface 34.

Description

  The present invention relates to an endoscope provided with a fluid ejection nozzle that ejects fluid toward an observation window.

  An endoscope has an observation window for capturing image light of a subject at the distal end of an insertion portion that is inserted into the subject, and fluid ejection (feeding water or air) toward the observation window. Air / water) nozzle. The observation window and the fluid ejection nozzle are arranged on a flat surface orthogonal to the axial direction of the insertion portion. Conventionally, an observation window generally has a surface that serves as a light incident surface formed in a plane parallel to the flat surface of the insertion portion. Since dirt adheres, water is ejected from the ejection port of the fluid ejection nozzle to wash away the dirt on the observation window, and air droplets are ejected from the ejection port to blow away water droplets remaining on the surface of the observation window. Since it is difficult to observe if dirt or water droplets remain in a part of the observation window, it is preferable that the fluid ejected from the fluid ejection nozzle spread over the entire surface of the observation window.

  For this reason, in the endoscope described in Patent Document 1, the surface of the observation window is arranged so as to protrude by a predetermined height with respect to the flat surface of the insertion portion, and the flat surface is extended over the entire periphery of the periphery of the observation window. An inclined portion that is inclined so as to gradually increase in height toward the surface of the observation window is formed. Since the fluid ejected from the ejection port of the fluid ejection nozzle hits the inclined portion and smoothly flows toward the surface of the observation window, the fluid can be spread over the entire surface of the observation window. The fluid that has passed through the surface of the observation window descends the inclined portion on the side opposite to the fluid ejection nozzle and flows to a flat surface. By providing the inclined portion in this way, the cleaning property of the observation window and the water drainage property of the sprayed water are improved.

Japanese Patent Laid-Open No. 2003-210388

  The conventional endoscope has a problem that distortion occurs in the peripheral portion of the subject image captured from the objective optical system including the observation window. Therefore, the present applicant uses an optical lens whose surface is convex with respect to the flat surface at the tip of the insertion portion, not an observation window having a flat surface, and corrects distortion at the peripheral portion. I am considering that.

  However, in the endoscope described in Patent Document 1, when the height of the inclined portion provided on the entire circumference of the observation window is added with the amount of forming the surface of the observation window on the convex lens surface for correcting distortion of the peripheral portion. Further, since the amount of projection of the observation window from the flat surface becomes large, there is a high possibility that the observation window is damaged, for example, the surface is scratched.

  The present invention has been made in view of the above problems, and provides an endoscope capable of suppressing the amount of projection of the observation window from the distal end of the insertion portion and improving the cleaning performance and drainage of the observation window. With the goal.

  The endoscope of the present invention is provided at a distal end portion of an insertion portion to be inserted into a subject, a flat surface perpendicular to the axial direction of the insertion portion, and a convex lens surface that is disposed on the flat surface and is a light incident surface Includes an observation window provided so as to protrude from the flat surface, and a fluid injection nozzle that is disposed on the flat surface and injects fluid from an injection port toward the convex lens surface, and the fluid injection nozzle includes the convex lens surface. The ejection port is located on a first straight line connecting the apex of the convex lens surface and the downstream end of the fluid ejection direction on the convex lens surface, and the fluid ejection direction is parallel to the first straight line, A range including at least from a second straight line parallel to the first straight line and in contact with the convex lens surface to a third straight line parallel to the first straight line and passing through the upstream end in the fluid ejection direction on the convex lens surface. The injection port is arranged in And wherein the Rukoto.

  The tip portion is formed with an inclined surface that is inclined in parallel with the inclination of the convex lens surface from a boundary with the downstream end of the fluid ejection direction on the convex lens surface toward a position that is one step concave from the flat surface. Preferably it is.

  The inclined surface is preferably an arc-shaped inclined surface along the periphery of the convex lens surface.

  The inclined surface is preferably a flat inclined surface that intersects the flat surface.

  It is preferable that the observation window is disposed so that the position of the peripheral edge of the convex lens surface with respect to the flat surface protrudes toward the tip side with a protrusion amount equal to or less than the thickness of the fluid ejection nozzle.

  The observation window is preferably arranged so that the convex lens surface is inclined toward the fluid ejection nozzle with respect to the flat surface.

  According to the endoscope of the present invention, the fluid ejection nozzle has the ejection port located on the first straight line connecting the apex of the convex lens surface and the downstream end in the fluid ejection direction on the convex lens surface, and ejects the fluid. The direction is parallel to the first straight line, and the second straight line parallel to the first straight line and in contact with the convex lens surface is parallel to the first straight line and passes through the upstream end of the fluid ejection direction at the periphery of the convex lens surface. Since the injection port is arranged in a range including at least up to the 3 straight line, it is possible to improve the cleaning property and drainage property of the observation window while suppressing the projection amount of the observation window from the distal end of the insertion portion.

It is an external appearance perspective view of an endoscope system. It is a perspective view which shows the structure of the front-end | tip part of an electronic endoscope. It is sectional drawing of the front-end | tip part along an observation window and a fluid injection nozzle. It is principal part sectional drawing which shows the positional relationship of the fluid injection nozzle with respect to a convex lens surface. It is principal part sectional drawing which shows 2nd Embodiment which made the convex lens surface protrude from the flat surface with the protrusion amount below the thickness of the fluid injection nozzle. It is a perspective view which shows the structure of the front-end | tip part of 2nd Embodiment. It is principal part sectional drawing which shows 3rd Embodiment which inclined the convex lens surface to the fluid injection nozzle side. It is a perspective view which shows another Example of the shape of an inclined surface.

  As shown in FIG. 1, the electronic endoscope system 11 includes an electronic endoscope 12, a processor device 13, a light source device 14, an air / water supply device 15, and the like. The air / water supply device 15 is built in the light source device 14 and is a well-known air supply device (pump or the like) 15a for supplying air, and a wash water tank that is provided outside the light source device 14 and stores wash water. 15b. The electronic endoscope 12 is connected to a flexible insertion portion 16 that is inserted into the body of a subject, an operation portion 17 that is connected to a proximal end portion of the insertion portion 16, a processor device 13, and a light source device 14. Connector 18, and a universal cord 19 that connects between the operation unit 17 and the connector 18. The connector 18 is a composite type connector to which the processor device 13, the light source device 14, and the air / water supply device 15 are connected.

  The insertion portion 16 is provided at the distal end thereof, and includes a distal end portion 16a in which a CCD type image sensor (see FIG. 2; hereinafter referred to as CCD) 37 as an imaging device for in-subject imaging, and a distal end portion 16a. It comprises a bendable bending portion 16b provided continuously at the base end, and a flexible flexible tube portion 16c provided continuously at the base end of the bending portion 16b. Hereinafter, the distal end side of the insertion portion 16 is simply referred to as “distal end side”, and the proximal end side of the insertion portion 16 is simply referred to as “proximal end side”.

  The processor device 13 is electrically connected to the light source device 14 and comprehensively controls the operation of the electronic endoscope system 11. The processor device 13 supplies power to the electronic endoscope 12 via the universal cord 19 or a transmission cable inserted into the insertion portion 16 and controls the drive of the CCD 37. Further, the processor device 13 acquires an imaging signal output from the CCD 37 via a transmission cable, and performs various image processing to generate image data. The image data generated by the processor device 13 is displayed as an observation image on a monitor 20 connected to the processor device 13 by a cable.

  An air supply / water supply channel 21 (see FIG. 2) is arranged inside the insertion portion 16 and the operation portion 17, and the air supply / water supply channel 21 is provided with an air supply / water supply nozzle (provided at the distal end portion 16 a). It is connected to a fluid injection nozzle) 22 (see FIG. 2). The air / water supply channel 21 is connected to the air / water supply device 15 through the universal cord 19.

  The operation unit 17 is provided with a forceps port 23 through which various treatment tools having an injection needle, a high-frequency knife and the like are inserted, an air / water supply button 24, an angle knob 25, and the like. When the air supply operation is performed by the air supply / water supply button 24, the air generated by the air supply device 15a is sent to the air supply / water supply nozzle 22, and when the water supply operation is performed, the air pressure generated by the transmitter device 15a is Wash water is sent from the wash water tank 15 b to the air / water feed nozzle 22. The air / water supply nozzle 22 selectively injects air and cleaning water supplied via the air / water supply channel 21.

  Further, when the angle knob 25 is operated, the bending portion 16b is bent in the vertical and horizontal directions by pushing and pulling the wire inserted in the insertion portion 16. Thereby, the front-end | tip part 16a is orient | assigned to the desired direction in a body cavity.

  As shown in FIGS. 2 and 3, the distal end portion 16a includes a distal end portion main body 26, a cap-shaped distal end protective cap 27 attached to the distal end side of the distal end portion main body 26, an observation window 28, illumination windows 29a and 29b, A forceps outlet 30 and an air / water supply nozzle 22 are provided. In the distal end portion body 26, through holes 26 a and 26 b are formed along the axial direction of the insertion portion 16 to hold components such as an air / water supply nozzle 22 and an objective lens unit 33 described later. The rear end of the distal end body 26 is connected to a bending piece 31 on the distal end side that constitutes the bending portion 16b.

  The tip protection cap 27 includes a tip plate portion 27 a that covers the tip side of the tip portion main body 26, and a cylindrical portion 27 b that covers the outer peripheral surface of the tip portion main body 26. An outer skin layer 32 covering the outer peripheral surface of the curved portion 16b extends to the distal end body 26, the distal end of the outer skin layer 32 and the rear end of the cylindrical portion 27b are brought into contact with each other, and the end portions are fixed by an adhesive or the like. . The distal end plate portion 27 a is formed with a flat surface 27 c that is a surface orthogonal to the axial direction of the insertion portion 16 and constitutes the distal end surface of the insertion portion 16.

  The distal end plate portion 27a is formed with an observation window 28, illumination windows 29a and 29b, through holes 27d to 27g for exposing the air / water supply nozzle 22 from the flat surface 27c, and a forceps outlet 30. The observation window 28 is disposed near the center of the flat surface 27 c, and the two illumination windows 29 a and 29 b are disposed at symmetrical positions with respect to the observation window 28.

  The observation window 28 is a state-of-the-art objective lens that constitutes the objective lens unit 33, and also serves as a cover glass. The observation window 28 has a substantially disk-shaped outer shape, and includes a convex lens surface 34 that is a light incident surface and an outer peripheral surface 35 that is continuous with the convex lens surface 34. The convex lens surface 34 corrects distortion in the peripheral portion of the image captured by the optical system of the objective lens unit 33.

  The optical system of the objective lens unit 33 including the observation window 28 is held by a lens barrel 36. The lens barrel 36 is formed so as to cover the base end side of the outer peripheral surface 35 of the observation window 28, and the tip end surface has a step with respect to the convex lens surface 34. In the observation window 28, the distal end side of the outer peripheral surface 35 is fitted into the through hole 27 d of the distal end protection cap 27. The lens barrel 36 is fitted into the through hole 26 a of the distal end portion body 26, and the distal end surface abuts against the distal end plate portion 27 a of the distal end protection cap 27. Thereby, the top T of the convex lens surface 34 protrudes from the flat surface 27c, and the peripheral edge of the convex lens surface 34 is attached to the same surface as the flat surface 27c.

  A CCD 37 is attached to the back of the objective lens unit 33. The CCD 37 is composed of, for example, an interline transfer type CCD, and a subject image captured by the optical system of the objective lens unit 33 is formed on the imaging surface. Note that the image sensor is not limited to the CCD 37 and may be a CMOS.

  The illumination windows 29a and 29b also serve as irradiation lenses, and irradiate illumination light from the light source device 14 to an observation site in the subject. The exit end of the light guide (not shown) faces the illumination windows 29a and 29b. The light guide is formed by bundling a large number of optical fibers (for example, made of quartz). The light guide passes through the insertion portion 16, the operation portion 17, the universal cord 19, and the connector 18, and guides the illumination light from the light source device 14 to the illumination windows 29a and 29b. The forceps outlet 30 is connected to a forceps channel (not shown) disposed in the insertion portion 16 and communicates with the forceps port 23 of the operation portion 17. The tips of various treatment tools inserted through the forceps port 23 are exposed from the forceps outlet 30.

  The air / water supply nozzle 22 is integrally formed with an injection cylinder portion 22a on the distal end side and a connection cylinder portion 22b on the proximal end side. The connecting cylinder portion 22 b is connected to the air / water supply channel 21 by being fitted to the outer peripheral surface of the air supply / water supply channel 21. Further, the connecting cylinder part 22 b and the air / water supply channel 21 are fitted in the through hole 26 b of the tip end body 26. The injection cylinder portion 22 a is formed in a cylindrical shape that is smoothly bent from the connection cylinder portion 22 b to the injection port 38 at the tip, and is exposed to the outside through the through hole 27 g of the tip protection cap 27.

FIG. 4 shows the injection direction S when the fluid is injected from the injection port 38 of the air / water supply nozzle 22 and the arrangement of the injection ports 38. Note that the symbol T is the apex of the convex lens surface 34 and indicates the most protruding portion in the thickness direction of the observation window 28 as an objective lens. Reference numeral E ₁ is a downstream end of the convex lens surface 34 in the fluid ejection direction, and indicates a position farthest from the air / water supply nozzle 22 at the periphery of the convex lens surface 34. Furthermore, the symbol E ₂ is the upstream end E ₂ in the fluid ejection direction on the convex lens surface 34, and indicates the location closest to the air / water supply nozzle 22 at the periphery of the convex lens surface 34.

Gas supply and water supply nozzle 22, and the vertex T of the convex lens surface 34, and the injection port 38 to the first upper straight line L ₁ which connects the injection direction downstream end E ₁ of the fluid in the convex lens surface 34 is located still and injection injecting direction S when injecting the fluid from the mouth 38, are arranged parallel to the first and the straight line L _1, the injection tube portion 22a is arranged to fit the injection direction S. Further, in the first straight line L ₁ parallel and the upper end 38a of the second straight line L injection port 38 on the _two contacting a convex lens surface 34 and the contact P is located, the first straight line L ₂ parallel and convex lens surface 34 bottom 38b of the injection port 38 on the third straight line L ₃ through the injection upstream end E ₂ of the fluid are located.

Jetting direction downstream end E ₁ against the apex T of the convex lens surface 34 located on the proximal side. For this reason, the ejection direction S parallel to the first straight line L ₁ connecting the vertex T and the downstream end E _{1 in the} ejection direction is determined so as to spray fluid from the obliquely upper side of the convex lens surface 34 toward the convex lens surface 34. ing.

The tip protection cap 27 has a tip concave portion 27h that is one step concave from the flat surface 27c at a position opposite to the air / water feeding nozzle 22 with the convex lens surface 34 interposed therebetween, and a fluid ejection direction downstream of the convex lens surface 34. An inclined surface 39 (see also FIG. 3) that is inclined from the boundary with the end E ₁ , that is, from the end edge of the through hole 27 d that is in contact with the downstream end E ₁ in the injection direction, toward the distal end recess 27 h is formed. The inclined surface 39 is an arc-shaped inclined surface that is inclined in parallel with the inclination of the convex lens surface 34 at the downstream end E ₁ in the ejection direction and is further along the peripheral edge of the convex lens surface 34.

A process when the observation window 28 is cleaned by fluid ejection from the air / water supply nozzle 22 using the electronic endoscope 12 having the above-described configuration will be described. As described above, gas supply and water supply nozzle 22, lines L ₁ injection direction S is first when the injection port 38 to the first upper straight line L ₁ is located, should be noted and fluid ejected from the ejection nozzle 38 Therefore, the fluid (cleaning water or air) ejected from the ejection port 38 strikes the convex lens surface 34 obliquely from above along the ejection direction S. Further, the upper end 38a of the injection port 38 to the second upper straight line L ₂ in contact with the first straight line L ₁ parallel and convex lens surface 34 is located, the injection direction upstream of the first straight line L ₁ parallel and convex lens surface 34 to position the lower end 38b of the injection port 38 on the third straight line L ₃ through the end E _2, the range from the injection upstream end E ₂ of the convex lens surface 34 to the contact point P, is injected from the injection port 38 Direct contact with fluid. In still range from point P to the injection direction downstream end E _1, fluid striking the range from the injection upstream end E ₂ to the contact P flows along the curved surface of the convex lens surface 34. As a result, the wash water sprayed from the air / water feed nozzle 22 spreads over the entire surface of the convex lens surface 34 and the liquid and dirt attached to the observation window 28 are washed. Further, the cleaning water is also blown away by the jet of air. As described above, in the electronic endoscope 12 of the present embodiment, it is possible to improve the cleaning property and drainage property of the observation window 28.

  In the conventional endoscope, the observation window is arranged so as to protrude from the flat surface of the insertion portion by the height of the inclined portion provided on the entire circumference of the observation window. Without providing a portion, it is possible to improve the cleaning property and drainage of the observation window 28, and the observation window 28 protrudes from the flat surface 27c by the amount formed on the convex lens surface 34 as the surface of the observation window 28. become. Therefore, the present invention can prevent the observation window 28 from being damaged by suppressing the projection amount of the observation window 28 from the flat surface 27c.

  Further, the tip protection cap 27 is provided with an inclined surface 39 that is inclined from the boundary with the downstream end E1 in the ejection direction of the convex lens surface 34 toward the tip concave portion 27h, and the fluid ejected to the convex lens surface 34 is It flows smoothly along the convex lens surface 34 and the inclined surface 39. As a result, the fluid over the convex lens surface 34 does not rebound. When the flat surface 27c continues at the same height up to the downstream side in the ejection direction of the convex lens surface 34 (opposite to the air / water feeding nozzle 22), the water sprayed on the convex lens surface 34 rebounds on the flat surface 27c. Since the reverse flow or air may hit the flat surface 27c and float up, the cleaning property and drainage of the observation window 28 are deteriorated. However, in the present invention, the inclined surface 39 is provided. Absent.

In the first embodiment, the observation window 28 is arranged on the same surface as the flat surface 27c by aligning the peripheral edge of the convex lens surface 34. However, the present invention is not limited to this, and is shown in FIGS. As in the distal end portion 40 of the second embodiment, the observation window 28 is disposed by projecting the position of the peripheral edge of the convex lens surface 34 with respect to the flat surface 27c toward the distal end with a projection amount less than the thickness of the air / water feeding nozzle 22. May be. In FIGS. 5 and 6, components using the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted. Further, reference numeral D is the thickness of the gas supply and water supply nozzle 22, the inclination angle of the jetting direction S of the gas supply and water supply nozzle 22 symbols α with respect to the flat surface 27c, reference numeral H ₁ is the convex lens surface 34 with respect to the flat surface 27c periphery of Indicates the amount of protrusion.

The distal end portion 40 of the second embodiment, since the wall thickness less D projection amount H ₁ of the air and water supply nozzle 22, and is projected to the position of the periphery of the convex lens surface 34 with respect to the flat surface 27c, gas supply and The injection port 38 of the water supply nozzle 22 and the convex lens surface 34 can be disposed close to each other. The injection port 38 of the air / water supply nozzle 22 is separated from the flat surface 27c by at least the thickness D. Therefore, in the first embodiment, since the thickness D is present, the distance G ₁ (see FIG. 4) between the injection port 38 of the air / water supply nozzle 22 and the convex lens surface 34 is separated by (D / tan α) or more. it is necessary, unless the gap G ₁ to (D / tan [alpha) above, it is impossible to apply the fluid to the injection direction the upstream end E ₂ of the convex lens surface 34. In contrast, in the present embodiment, by projecting the position of the periphery of the convex lens surface 34 at the projecting amount H ₁ of the following wall thickness D of the gas supply and water supply nozzle 22 with respect to the flat surface 27c, the injection port from the flat surface 27c The peripheral edge of the convex lens surface 34 can be arranged at substantially the same position as the distance 38 is separated. Therefore, it is possible to reduce the distance G ₂ between the injection port 38 and the convex lens surface 34 of the gas supply and water supply nozzle 22.

Further, as shown in FIG. 6, the inclined surface 41 provided on the tip portion 40, similar to the inclined surface 39 of the first embodiment, inclined parallel to the inclination of the convex lens surface 34 in the direction of injection downstream end E ₁ Further, it is an arcuate inclined surface along the periphery of the convex lens surface 34, and the upper end of the inclined surface 41 is also disposed at a position where the upper end of the inclined surface 41 protrudes from the flat surface 27c by the extent that the periphery of the convex lens surface 34 protrudes from the flat surface 27c. ing.

In the present embodiment, are disposed by protruding the periphery of the convex lens surface 34 at a thickness less D projection amount H ₁ of the air and water supply nozzle 22, the projection amount H ₁ is a conventional endoscopic Like a mirror, the projection amount is smaller than the projection amount when the observation window is arranged so as to project from the flat surface of the insertion portion in accordance with the height of the inclined portion provided on the entire circumference of the observation window. This is because the fluid from the air / water supply nozzle 22 is hit, and the height of the inclined portion needs to exceed the thickness D of the air / water supply nozzle 22. Therefore, in the present embodiment in which the inclined portion is not provided, it is possible to prevent the observation window 28 from being damaged by suppressing the projection amount of the observation window 28 from the flat surface 27c.

  In the first and second embodiments, the convex lens surface is aligned with the periphery of the convex lens surface 34 on the same surface as the flat surface 27c, or with a projection amount equal to or less than the wall thickness D of the air / water supply nozzle 22 from the flat surface 27c. The observation window 28 is arranged at a position where the peripheral edge of the projection 34 protrudes. However, the present invention is not limited to this, and the flat surface 27c is formed like the tip 50 of the third embodiment shown in FIG. The observation window 28 may be arranged so that the convex lens surface 34 is inclined toward the air / water supply nozzle 51. In FIG. 7, components using the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  In the distal end portion 50 of the third embodiment, the objective lens unit 33 including the observation window 28 is disposed at an angle β with respect to the axial direction of the distal end portion 50. As a result, the convex lens surface 34 is inclined at the angle β toward the air / water supply nozzle 51 with respect to the flat surface 27c. The air / water supply nozzle 51 is integrally formed with an injection cylinder portion 51a on the distal end side and a connection cylinder portion 51b on the proximal end side.

The injection direction by the air / water supply nozzle 51 and the arrangement of the injection ports 52 of the air / water supply nozzle 51 are determined by the positional relationship with respect to the convex lens surface 34 as in the first embodiment. That is, the injection direction S when the injection port 52 to the first upper straight line L ₁ connecting the vertex T and injection direction downstream end E ₁ of the convex lens surface 34 is located still and fluid ejected from the ejection nozzle 52 is first It is parallel to the straight line L _1. Further, the upper end 52a of the injection port 52 to the second upper straight line L ₂ in contact with the first straight line L ₁ parallel and convex lens surface 34 is located, the injection direction upstream of the first straight line L ₁ parallel and convex lens surface 34 bottom 52b of the injection port 52 is positioned in the third straight line _{L 3} of the passing edge _{E 2.}

In the third embodiment, as described above, the relative positional relationship of the air / water supply nozzle 51 with respect to the convex lens surface 34 is the same as that in the first embodiment, but the convex lens surface 34 has the air / water supply nozzle 51. by being the angle β min inclined side, the vertex T and injection direction downstream end of the convex lens surface 34 E ₁ also inclined angle β min to the air and water supply nozzle 51 side. For this reason, the angle of the injection direction S with respect to the flat surface 27c can be reduced, and the injection direction S can be arranged so as to be substantially parallel to the flat surface 27c. Therefore, it is possible to flat surface 27c substantially parallel to provided a jet pipe portion 51a of the gas supply and water supply nozzle 51, the projection amount of H ₂ gas supply and water supply nozzle 51 with respect to the flat surface 27c of the first and second It can be made smaller than in the second embodiment.

In the above first to third embodiments, the boundary between the injection direction downstream end E ₁ of the convex lens surface 34, an inclined surface 39 which is inclined toward the tip recess in the concave a position than the flat surface 27c, the convex lens surface Although formed in a circular arc shape along the 34 periphery of the shape of the inclined surface is not limited to this, as the tip 60 shown in FIG. 8, and the injection direction downstream end E ₁ of the convex lens surface 34 The inclined surface 61 that inclines from the boundary toward the tip recess 27h may be formed as a flat inclined surface that intersects the flat surface 27c.

In the first and second embodiment, the upper end 38a of the injection port 38, 52 on the second straight line _{L 2,} 52a is located, the third straight line _{L 3} bottom 38b of the injection port 38, 52 on, 52b tip Although but positioned, over the second straight line L _2, it may be disposed to range the injection port 38, 52 includes at least up to the third straight line L _3, for example, than the second straight line L ₂ above the upper end 38a of the injection port 38, 52 to the side, arranged 52a, third straight line _{L 3} the lower end of the injection port 38, 52 proximal to the top 38b, the injection port 38, 52 so as to place 52b It may be provided.

  In the above-described embodiment, an electronic endoscope that observes an image obtained by imaging the state of the subject using the imaging apparatus is described as an example. However, the present invention is not limited to this, and an optical image is not limited thereto. The present invention can also be applied to an endoscope that employs a guide and observes the state of a subject.

12 Electronic endoscope 16 Insertion part 16a, 40, 50, 60 Tip part 21 Air supply / water supply channel 22, 51 Air supply / water supply nozzle (fluid injection nozzle)
27c Flat surface 27h Tip concave portion 28 Observation window 34 Convex lens surface 39, 41, 61 Inclined surface E ₁ Downstream end in the injection direction E ₂ Upstream end in the injection direction L ₁ First straight line L ₂ Second straight line L ₃ Third straight line T vertex

Claims (6)

A flat surface provided at the distal end of the insertion portion to be inserted into the subject, and perpendicular to the axial direction of the insertion portion;
An observation window disposed on the flat surface and provided with a convex lens surface that is a light incident surface protruding from the flat surface;
A fluid ejection nozzle disposed on the flat surface and ejecting fluid from an ejection port toward the convex lens surface;
In the fluid ejection nozzle, the ejection port is located on a first straight line connecting the apex of the convex lens surface and the downstream end of the fluid ejection direction on the convex lens surface, and the fluid ejection direction is the first direction. The second straight line parallel to the first straight line and parallel to the first straight line and in contact with the convex lens surface is parallel to the first straight line and passes through the upstream end in the fluid ejection direction on the convex lens surface. The endoscope is characterized in that the injection port is arranged in a range including at least up to 3 straight lines.   The tip portion is formed with an inclined surface that is inclined in parallel with the inclination of the convex lens surface from a boundary with the downstream end of the fluid ejection direction on the convex lens surface toward a position that is one step concave from the flat surface. The endoscope according to claim 1, wherein:   The endoscope according to claim 2, wherein the inclined surface is an arc-shaped inclined surface along a peripheral edge of the convex lens surface.   The endoscope according to claim 2, wherein the inclined surface is a flat inclined surface intersecting with the flat surface.   2. The observation window is disposed with a protruding amount less than a thickness of the fluid ejection nozzle, and a position of a peripheral edge of the convex lens surface with respect to the flat surface is protruded toward a tip side. The endoscope according to any one of 4 above.   The endoscope according to any one of claims 1 to 4, wherein the observation window is disposed such that the convex lens surface is inclined toward the fluid ejection nozzle with respect to the flat surface.

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