Endoscope tip part, endoscope, and method for assembling endoscope tip part

Abstract

An endoscope tip according to the present invention includes: a tip-constituting part 20 having an observation window 25a; a first cover 21 disposed outside the tip-constituting part and covering part of the tip-constituting part; a second cover 22 disposed outside the tip-constituting and covering a portion different from the part of the tip-constituting part; a bending part 6 connected at the base end side of the tip-constituting part; a tube 32 covering the bending part and having a tip part disposed closer to the base end side than each base end part of the first cover and the second cover; and a ring-shaped adhesive 24 covering part of the outer surface of the tip-constituting part, the base end part of the first cover, the base end part of the second cover, and the tip part of the tube.

Description

Endoscopic distal end, endoscope, and method for assembling an endoscopic distal end

[0001] The present invention relates to a structure of an endoscopic distal end, an endoscope to which the endoscopic distal end is applied, and a method for assembling the endoscopic distal end.

[0002] Conventionally, endoscopes are widely used in, for example, the medical field and the industrial field. A medical endoscope used in the medical field includes a distal end portion including an imaging unit, a lighting unit, etc., and a bending portion connected to this distal end portion, and has an endoscope insertion portion having an overall elongated tube shape. And this endoscope insertion portion is inserted into the body cavity of a living body to acquire an image of an internal lesion portion of an organ or the like. The image thus obtained is used for image diagnosis or the like by observing or inspecting the lesion portion or the like.

[0003] As a basic structure of the endoscopic distal end in this type of conventional endoscope, for example, a basic constituent member having an imaging unit, a lighting unit, etc. inside, a cover member that covers and protects a part of the outer surface of this basic constituent member, It is mainly composed of an annular member or the like that covers and watertightly fixes the outer surface of the connecting portion between the proximal ends of the basic constituent member and the cover member and the distal end of the bending tube. Various ones are disclosed, for example, by Japanese Patent Publication No. 6854963 and are generally well-known.

[0004] Here, an observation window, a lighting window, etc. are arranged on a part of the outer surface of the basic constituent member. Therefore, it is normal for the cover member to be formed with openings that expose these observation windows, lighting windows, etc. toward the outside.

[0005] Further, in the conventional endoscopic distal end, for example, there is one configured with a treatment tool lifting platform for arbitrarily changing the protruding direction of a treatment tool or the like protruding forward from an opening that opens toward the distal end within a predetermined range.

[0006] The cover member in the endoscopic distal end having such a configuration is formed with an opening for securing a movable region when the treatment tool lifting platform is lifted and inverted and a region where the treatment tool protrudes.

[0007] Japanese Patent Publication No. 6854963

[0008] However, in the conventional endoscope tip structure disclosed in Japanese Patent Publication No. 6854963, etc., a cover member covers the outer surface of the basic component member, and an annular member covers the outer surface of the base end of the cover member, so that the components are arranged to overlap radially. As a result, the outer diameter of the connection portion between the base end of the endoscope tip and the tip of the curved tube tends to be large.

[0009] In general, there is a constant demand for smaller diameters in medical endoscopes, from the perspective of improving insertability and reducing the burden on the subject (patient, etc.). Furthermore, in recent years, pediatric endoscopes (e.g., duodenoscopes) have been proposed and are being put into practical use, so there is a strong desire for smaller diameters in these types of endoscopes.

[0010] Furthermore, in recent years, single-use endoscopes, which are discarded after a single use, have become widely used in medical endoscopes, for example, due to considerations such as infection control. This type of single-use endoscope has the advantage of eliminating the need for cleaning and sterilization processes that are carried out for reuse in conventional reusable endoscopes. On the other hand, because it is necessary to ensure a minimum level of watertightness, the structure becomes more complex, and as a result, manufacturing costs tend to increase.

[0011] However, with conventional endoscopes, there has always been a demand for reduced manufacturing costs and lower product prices, and this demand is particularly strong for single-use endoscopes.

[0012] The present invention aims to provide an endoscope tip, an endoscope, and a method for assembling an endoscope tip that can achieve the required watertight structure with a simple configuration, further reduce the diameter to improve insertability, and contribute to reducing manufacturing costs.

[0013] To achieve the above objective, an endoscope tip according to one aspect of the present invention comprises: a tip component having an observation window; a first cover disposed on the outside of the tip component and covering a part of the tip component; a second cover disposed on the outside of the tip component and covering a part of the tip component different from the aforementioned part; a curved portion connected to the base end of the tip component; a tube covering the curved portion, with the tip portion positioned more towards the base end than the base ends of the first and second covers; and a ring-shaped adhesive covering a part of the outer surface of the tip component, the base end of the first cover, the base end of the second cover, and the tip of the tube.

[0014] An endoscope according to one aspect of the present invention is characterized by comprising: a tip component having an observation window; a first cover disposed on the outside of the tip component and covering a part of the tip component; a second cover disposed on the outside of the tip component and covering a part of the tip component different from the part mentioned above; a curved portion connected to the base end of the tip component; a tube covering the curved portion and having its tip portion disposed at the base ends of the first cover and the second cover; and a ring-shaped adhesive covering a part of the outer surface of the tip component, the base end of the first cover, the base end of the second cover, and the tip of the tube.

[0015] A method for assembling the tip of an endoscope according to one aspect of the present invention is a method for assembling the tip of an endoscope, comprising the steps of: positioning the first cover so that its first edge abuts against the contact portion of the tip component, thereby covering a portion of the outside of the tip component; positioning the second cover so that its second edge abuts against the contact portion of the tip component, thereby covering a portion of the outside of the tip component different from the aforementioned portion; fixing the first edge of the first cover and the contact portion of the tip component with an adhesive; fixing the second edge of the second cover and the contact portion of the tip component with an adhesive; fixing the boundary portion between the first cover or the second cover and the tip component, other than the first and second edges, with the adhesive; and adhesively fixing the base end of the tip component, the base end of the first cover, the base end of the second cover, and the tip of the curved tube with a ring-shaped adhesive.

[0016] According to the present invention, it is possible to provide an endoscope tip, an endoscope, and a method for assembling the endoscope tip that can achieve the required watertight structure with a simple configuration, further reduce the diameter, improve insertability, and contribute to reducing manufacturing costs.

[0017] Figure 2 shows an external perspective view illustrating the schematic configuration of an endoscope including the tip of an endoscope according to one embodiment of the present invention, an enlarged perspective view showing the tip of an endoscope according to one embodiment of the present invention, an exploded perspective view showing the endoscope tip of Figure 2 in disassembled form, a side view showing only the illumination unit among the components of the endoscope tip of Figure 2 in enlarged form, a top view of the endoscope tip as seen from the direction of arrow [5] in Figure 2, a side view of the endoscope tip as seen from the direction of arrow [6] in Figure 2, a perspective view of the endoscope tip as seen from the direction of arrow [7] (front and downward) in Figure 2, a front view of the endoscope tip as seen from the direction of arrow [8] in Figure 2, and the arrow in Figure 2 A cross-sectional perspective view of the cross-section indicated by the mark [9], a cross-sectional view of the cross-section indicated by the arrow

[10] in Figure 2, a perspective view of the endoscope tip in Figure 2 with the first cover (and second cover) removed, an exploded perspective view of the state in Figure 11 with the treatment instrument lifting stand removed, an enlarged perspective view of the main part showing the vicinity of the fluid delivery nozzle (third cover) in the endoscope tip in Figure 2, an enlarged cross-sectional view of the main part showing the portion of the cross-section along the long axis of the endoscope tip in Figure 2 with the fluid delivery nozzle (third cover) enlarged, and a perspective view of the endoscope tip in Figure 2 with the fluid delivery nozzle (third cover) enlarged. Figure 16 shows a cross-sectional perspective view of the endoscope tip, showing only the main parts, primarily the lower and posterior sides, a schematic diagram showing the curved section included in the endoscope tip of Figure 2, a schematic diagram showing the internal structure of the curved section of Figure 16, a schematic diagram showing a part of the endoscope tip near the insertion section of Figure 1, a cross-sectional view of the insertion section of Figure 18 along the long axis, from the tip to the vicinity of the connection between the tip and the curved section, a cross-sectional view of the insertion section of Figure 18 along the long axis, showing the vicinity of the connection between the curved section and the flexible tube section, and a schematic perspective view showing the placement of the second cover in the endoscope tip of Figure 2. Figure 2 shows an external perspective view of the endoscope tip before the first cover is attached to the tip component, Figure 2 shows an external perspective view of the state after the first cover is attached from the state in Figure 22, a conceptual diagram showing the configuration of the stopping mechanism for the raised position of the treatment instrument stand at the endoscope tip in Figure 2, a cross-sectional view conceptually showing the configuration of the stopping mechanism for the inverted position of the treatment instrument stand at the endoscope tip in Figure 2, a cross-sectional view along the line

[26] -

[26] in Figure 24, a cross-sectional view along the line

[27] -

[27] in Figure 24, and a partial component (first cover, treatment instrument stand,Figure 2 shows the state with the second cover removed, a schematic perspective view from a different direction than Figure 11, a conceptual diagram showing the field of view V of the imaging unit when the treatment instrument lifting platform is in the raised position at the tip of the endoscope in Figure 2, a cross-sectional view showing the configuration of the treatment instrument lifting operation wire and the attachment structure of the treatment instrument lifting operation wire to the tip component at the tip of the endoscope in Figure 2, a cross-sectional view along the line

[31] -

[31] in Figure 30 (Figure 35), an enlarged perspective view schematically showing the shape of the base end surface of the tip component at the tip of the endoscope in Figure 2, an external perspective view of a part of the treatment instrument lifting operation wire taken out and viewed from a position closer to the base end at the tip of the endoscope in Figure 2, an external perspective view of a part of the treatment instrument lifting operation wire taken out and viewed from a position closer to the tip at the tip of the endoscope in Figure 2, the line

[35] -

[35] in Figure 31 A cross-sectional view along the curve, a perspective view from a different direction than Figure 11 showing the endoscope tip in Figure 2 with some components removed, a schematic perspective view showing the connection between the bending section and the flexible tube section 7 in the endoscope of Figure 1, a cross-sectional view of the cut surface indicated by arrow

[38] in Figure 37 (Figure 20), an enlarged perspective view showing only the tip fitting included in the flexible tube section of Figure 37, a schematic perspective view showing the appearance of the flexible tube section in the endoscope of this embodiment, a cross-sectional view of the cut surface indicated by arrow

[41] in Figure 40, an enlarged exploded perspective view of the main part showing the connection structure between the flexible tube section and the operating section in Figure 40, a conceptual diagram showing the state in which each component unit (operating section and flexible tube section) is disassembled in the state of Figure 42, a cross-sectional view of the cut surface indicated by arrow

[44] in Figure 42, and an exploded perspective view showing a schematic configuration of a modified example of the endoscope tip of one embodiment of the present invention. Exploded perspective view showing a modified example.

[0018] The present invention will be described below with reference to the illustrated embodiments. The drawings used in the following description are schematic. Therefore, in these drawings, each component is shown at a size that is recognizable on the drawing. For this reason, the dimensional relationships and scales of each component may differ on the drawing. The present invention is not limited to the illustrated forms with respect to the quantity, shape, size ratio, relative positional relationships, etc., of each component shown in each drawing.

[0019] First, before describing the detailed configuration of the endoscope tip of one embodiment of the present invention, the general configuration of the endoscope to which the endoscope tip is applied will be described below using Figure 1. Figure 1 is an external perspective view showing the general configuration of an endoscope including the endoscope tip of one embodiment of the present invention.

[0020] As shown in Figure 1, the endoscope 1 is composed of an insertion section 2, an operating section 3, a universal cable 4, and the like.

[0021] The insertion section 2 is a long member shaped to be inserted into the lumen (inside organs, etc.) of a subject such as a living organism. The insertion section 2 has a flexible, elongated tube shape. The insertion section 2 is composed of a tip section 5, a curved section 6, and a flexible tube section 7. The insertion section 2 is connected to the operating section 3.

[0022] In the following explanation, the side of the insertion part 2 where the tip portion 5 is located will be referred to as the tip side. Also, the side of the insertion part 2 where the operating portion 3 is located will be referred to as the base end side.

[0023] Furthermore, in the following explanation, the term "endoscope tip" refers to the component unit composed of the tip portion 5 and the bending portion 6.

[0024] The tip section 5 is located on the tip side of the insertion section 2. The tip section 5 is equipped with an imaging unit 25, an illumination unit 26, a fluid delivery nozzle 23, a fluid delivery pipeline 19, etc. (details will be described later; see Figure 2 and later), as well as a treatment instrument lifting stand 50, etc., although these are not shown in Figure 1.

[0025] The curved section 6 has its tip connected to the base end of the tip section 5. The curved section 6 is a tubular unit that is configured to bend actively in response to the input of the bending operation knob 9, which will be described later.

[0026] The flexible tube section 7 has its tip connected to the base end of the curved section 6. The flexible tube section 7 has its base end connected to the tip of the operating section 3. The flexible tube section 7 is formed from a flexible tube.

[0027] The operating section 3 is connected to the base end of the insertion section 2. In other words, the insertion section 2 is located on the tip side of the operating section 3. The operating section 3 is composed of a treatment instrument insertion port 8, a bending operation knob 9, a treatment instrument operation lever 10, a bending fixing lever 11, and a plurality of operating members 12, etc. The treatment instrument insertion port 8 is an opening that connects to a treatment instrument insertion conduit 18 which is inserted into the insertion section 2. A forceps plug 8a is provided in the treatment instrument insertion port 8.

[0028] The bending operation knob 9 is an operating member for performing bending operations on the bending section 6. The bending operation knob 9 consists of two operating members: one for vertical bending operation and one for horizontal bending operation. The two operating members of the bending operation knob 9 are arranged on the outer surface of the operating section 3 in a superimposed configuration. In this case, the two operating members of the bending operation knob 9 are arranged to rotate freely around the same central axis, which is the rotation axis Ax.

[0029] Then, by rotating the bending operation knob 9, the bending operation wire (not shown; see reference numeral 33 in Figure 17, etc., described later) is pulled or released through a drive mechanism provided inside the operating section 3, thereby performing an active bending operation of the bending section 6.

[0030] The instrument operating lever 10 is an operating member that inputs the operating force for raising and lowering the instrument lifting base 50 provided at the tip 5. The instrument operating lever 10 is configured to rotate freely within a predetermined range with the same rotation axis Ax as the curved operation knob 9 as its center of rotation.

[0031] The instrument operating lever 10 is connected to the instrument lifting stand 50 through a drive mechanism (not shown) located inside the operating section 3 and an instrument lifting operation wire 17 that passes through the insertion section 2.

[0032] With this configuration, the operating input from the instrument operating lever 10 is transmitted to the instrument lifting stand 50. As a result, the instrument lifting stand 50 is configured to change the direction in which the tip of an instrument (not shown) inserted into the instrument insertion conduit 18 protrudes.

[0033] The curvature fixing lever 11 is an operating member that acts on the curvature operation knob 9 to fix the curvature of the curvature section 6 at a desired position. The curvature fixing lever 11 is configured to rotate freely within a predetermined range with the same rotation axis Ax as the curvature operation knob 9 as its center of rotation.

[0034] The bending locking mechanism of the bending section 6 by the bending locking lever 11 is not directly related to the present invention. Therefore, the detailed configuration and illustration of the bending locking lever 11 and the bending locking mechanism are omitted, as they are assumed to have the same configuration as those applied in conventional endoscopes.

[0035] The multiple operating members 12 include, for example, operating switches for appropriately performing predetermined operations on image data acquired by the endoscope 1. These predetermined operations on image data include, for example, switching between moving and still images, zooming in on images, recording images, and editing images.

[0036] Furthermore, the multiple operating members 12 include, for example, operating members for performing air supply / liquid supply operations and suction operations. Here, air supply / liquid supply operation is an operation that controls the fluid supply operation from the fluid supply nozzle 23 provided at the tip 5 by driving and controlling a fluid supply device (not shown).

[0037] Furthermore, the suction operation involves driving and controlling a suction device (not shown) to create negative pressure inside the instrument insertion conduit 18. By performing this suction operation, for example, mucus adhering to the tip 5 can be suctioned and removed from the instrument tip opening 18a (see Figure 3, etc., described later) of the instrument insertion conduit 18 provided at the tip 5.

[0038] The universal cable 4 is a composite cable extending from one side of the operating unit 3. A scope connector 14 is provided at the end of the universal cable 4. This scope connector 14 is a connector component that connects to an external device, a video processor (not shown), which includes a light source device. The scope connector 14 is composed of electrical contacts and other components, as well as a light guide connector 13.

[0039] Between the scope connector 14, the universal cable 4, the operating section 3, and the tip 5 of the insertion section 2, a light guide bundle 15, various signal lines 16, and a fluid delivery conduit 19 are inserted. The light guide bundle 15 is a component that guides the illumination beam emitted from a light source device included in a video processor (not shown) to the tip 5 of the insertion section 2. The illumination beam transmitted to the tip 5 by the light guide bundle 15 is emitted as illumination light that irradiates the object to be observed from an illumination unit 26 provided at the tip 5.

[0040] Furthermore, the various signal lines 16 include, for example, an imaging cable that transmits image signals (image data) acquired by the imaging unit 25 located in the tip 5 to a video processor (not shown), and a control signal cable that transmits control signals emitted from the video processor to constituent units such as the imaging unit. The general configuration of the endoscope 1 is as described above.

[0041] Next, the detailed configuration of the endoscope tip of one embodiment of the present invention will be described below with reference to Figures 2 to 23.

[0042] Figure 2 is an enlarged perspective view showing the endoscope tip of one embodiment of the present invention. Figure 3 is an exploded perspective view showing the endoscope tip of Figure 2 in disassembled form. Figure 4 is a side view showing only the illumination unit, one of the components of the endoscope tip of Figure 2, in enlarged form.

[0043] Figure 5 is a top view of the endoscope tip as seen from the direction of arrow [5] in Figure 2. Figure 6 is a side view of the endoscope tip as seen from the direction of arrow [6] in Figure 2. Figure 7 is a perspective view of the endoscope tip as seen from the direction of arrow [7] (front and downward) in Figure 2. Note that Figure 7 mainly shows the second cover. Figure 8 is a front view of the endoscope tip as seen from the direction of arrow [8] in Figure 2. Figure 9 is a cross-sectional perspective view of the cut surface indicated by arrow [9] in Figure 2. Figure 10 is a cross-sectional view of the cut surface indicated by arrow

[10] in Figure 2. Note that the cut surfaces indicated by arrows [8] and [9] in Figure 2 are both planes that include the optical axis of the observation window of the imaging unit.

[0044] Fig. 11 is a perspective view showing the state where the first cover (and the second cover) is removed at the distal end of the endoscope in Fig. 2. Fig. 12 is an exploded perspective view showing the state where the treatment instrument lifting table is removed from the state of Fig. 11.

[0045] Fig. 13 is a partial enlarged perspective view showing an enlarged view of the vicinity of the fluid delivery nozzle (the third cover) at the distal end of the endoscope in Fig. 2. Fig. 14 is a partial enlarged cross-sectional view showing an enlarged view of the portion near the fluid delivery nozzle (the third cover) in the cross-section along the longitudinal axis direction of the distal end of the endoscope in Fig. 2. Fig. 15 is a partial enlarged perspective view showing mainly the lower surface side and the back side by taking out only the fluid delivery nozzle (the third cover) at the distal end of the endoscope in Fig. 2.

[0046] Fig. 16 is a schematic configuration diagram showing the curved portion included in the distal end of the endoscope in Fig. 2 taken out. Fig. 17 is a cross-sectional perspective view showing the internal structure of the curved portion in Fig. 16.

[0047] Fig. 18 is a schematic configuration diagram showing a part near the tip of the insertion portion of the endoscope in Fig. 1. Fig. 19 is a cross-sectional view of the cross-section along the longitudinal axis direction of the insertion portion in Fig. 18 from the tip portion to the vicinity of the connection portion between the tip portion and the curved portion. Fig. 20 is a cross-sectional view showing the vicinity of the connection portion between the curved portion and the flexible tube portion in the cross-section along the longitudinal axis direction of the insertion portion in Fig. 18.

[0048] Fig. 21 is a schematic perspective view showing the arrangement portion of the second cover at the distal end of the endoscope in Fig. 2. In Fig. 21, the arrangement of the ring-shaped adhesive provided at the connection portion between the tip configuration portion, the base end portions of the first cover and the second cover, and the tip portion of the curved portion is also shown by a two-dot chain line.

[0049] Fig. 22 is an external perspective view showing the state before attaching the first cover to the tip configuration portion at the distal end of the endoscope in Fig. 2. In Fig. 22, since some of the constituent members (for example, the second cover, the ring-shaped adhesive, etc.) are in an uninstalled state, the illustration of these some constituent members is omitted. Fig. 23 is an external perspective view showing the state after attaching the first cover from the state of Fig. 22.

[0050] The endoscope tip of this embodiment is composed of a tip portion 5 and a curved portion 6. Of these, the tip portion 5 is mainly composed of a tip component 20, a first cover 21, a second cover 22, a fluid delivery nozzle 23 which is a third cover, and a ring-shaped adhesive 24.

[0051] The tip component 20 is a basic component of the tip component 5. The tip component 20 contains an imaging unit 25, an illumination unit 26, a treatment instrument lifting stand 50, etc., inside. For this purpose, the observation window 25a of the imaging unit 25 and the illumination window 26a of the illumination unit 26 are arranged on the outer surface of the tip component 20.

[0052] Furthermore, the tip component 20 is provided with a gap space 20a to secure a movable area for raising and lowering the treatment instrument lifting stand 50 and a protruding area for the treatment instrument. This gap space 20a is formed to extend from the tip to the base of the tip component 20 in a direction along the long axis of the tip component 20. When the tip 5 is viewed from above, the gap space 20a is formed between the first cover 21 and the tip component 20, as shown in Figure 5. The treatment instrument lifting stand 50 is positioned in this gap space 20a.

[0053] The imaging unit 25 is an imaging device that includes, for example, a MID (Molded Interconnect Device) on which an image sensor and imaging circuit are mounted, and an imaging optical system formed using a wafer lens or the like.

[0054] The observation window 25a included in the imaging optical system of the imaging unit 25 is positioned exposed on the outer surface of the tip component 20. In this case, the optical axis of the observation window 25a is positioned to extend in a direction substantially perpendicular to the long axis of the tip component 20 (towards the side of the tip component 20). Therefore, the endoscope 1 exemplifies a so-called side-view endoscope (for example, a duodenoscope) that observes the lateral view.

[0055] Here, the imaging unit 25 and the tip component 20 are bonded and fixed together around the entire circumference of the side surface of the imaging unit 25 using, for example, a thermosetting adhesive (see reference numeral [Ad] in Figures 5 and 10). In this way, the space between the tip component 20 and the imaging unit 25 is sealed in a watertight manner.

[0056] The illumination unit 26 is an illumination component that emits illumination light to irradiate the object to be observed. The illumination unit 26 is composed of, for example, an illumination window 26a, a PLG (plastic light guide) 26b, a PLG holder 26c, a PLG protective tube 26d, etc. (see Figures 3 and 4). Here, a light guide bundle 15 is composed of multiple PLGs 26b and PLG protective tubes 26d, etc.

[0057] The illumination window 26a is an illumination optical system formed by a transparent glass lens or the like, which directs the illumination beam towards a predetermined range.

[0058] The illumination window 26a is positioned exposed to the outer surface of the tip component 20. In this case, the illumination window 26a is positioned such that the illumination optical axis extends in a direction substantially perpendicular to the long axis direction of the tip component 20 (towards the side of the tip component 20). Therefore, the illumination unit 26 illuminates the side view field of the imaging unit 25.

[0059] Here, the illumination window 26a and the tip component 20 are bonded and fixed together using, for example, a thermosetting adhesive around the entire circumference of the side surface of the illumination window 26a (see reference numeral [Ad] in Figures 5 and 10). In this way, the space between the tip component 20 and the illumination window 26a is sealed in a watertight manner.

[0060] PLG26b is an optical transmission member that guides the illumination beam emitted from the light source device (not shown) to the tip 5. Multiple PLG26b are bundled together to form a light guide bundle 15. In this embodiment, an example is shown in which seven PLG26b are bundled together.

[0061] The PLG holder 26c is a cover member that bundles and protects the tips of multiple PLGs 26b. The PLG holder 26c is made of a material such as stainless steel. The bundle of PLGs 26c and PLGs 26b (light guide bundle 15) is bonded and fixed together using, for example, a light-curing adhesive (see reference numeral [Ad] in Figure 10). An example of a light-curing adhesive is, for example, an ultraviolet-curing adhesive. In the following description, when referring to a light-curing adhesive, it includes, for example, an ultraviolet-curing adhesive.

[0062] Here, the PLG holder 26c is positioned within the lighting storage section 20d (see Figure 10) of the tip component 20. The lighting storage section 20d has an upper opening 20da, a holder placement area 20db, and a stepped section 20dc.

[0063] The upper opening 20da is an opening facing the outer surface (side) of the tip component 20. An illumination window 26a is positioned in the upper opening 20da and fixed by adhesive.

[0064] The holder placement area 20db is an internal space formed by communication with the interior from the upper opening 20da. The PLG holder 26c is placed in the holder placement area 20db and fixed by adhesive.

[0065] The radial size of the holder placement area 20db is larger than the radial size of the upper opening 20da. As a result, a stepped portion 20dc is formed at the interface between the upper opening 20da and the holder placement area 20db.

[0066] The PLG holder 26c is inserted from below the holder placement area 20db toward the upper opening 20da. At this time, the upper surface of the outer peripheral edge of the PLG holder 26c abuts against the stepped portion 20dc, restricting its movement toward the upper opening 20da. As a result, the PLG holder 26c is positioned at a predetermined location within the holder placement area 20db of the lighting storage portion 20d.

[0067] In this way, the positioned PLG holder 26c is bonded and fixed to the tip component 20 around the entire circumference of the side surface of the PLG holder 26c using, for example, a moisture-curing adhesive or a thermosetting adhesive (see reference numeral [Ad] in Figure 10).

[0068] The PLG protective tube 26d is a tube member that protects the outer surface by inserting multiple PLGs 26b through it. The tip portion of the PLG protective tube 26d and the bundle of PLGs 26b (light guide bundle 15) are bonded and fixed together, for example, using a light-curing adhesive (see reference numeral [Ad] in Figure 10).

[0069] Furthermore, the lighting unit 26 is fixed to the tip component 20 by simply bonding the PLG holder 26c within the holder placement area 20db of the lighting storage section 20d, as described above. In other words, the light guide bundle 15, which bundles multiple PLGs 26b together, is not fixed even in the portion of the tip component 20 that extends from the lighting storage section 20d (see reference numeral [B] in Figure 10).

[0070] The treatment instrument lifting stand 50 is a component unit that is inserted into the treatment instrument insertion conduit 18 (see Figure 1) which is inserted into the insertion section 2, and is provided to change the direction of protrusion of the treatment instrument (not shown) that protrudes forward and outward from the treatment instrument tip opening 18a (see Figure 2, etc.) of the tip section 5, for example, to the side (see Figures 11 and 12).

[0071] Here, although not shown in the illustration, the instruments used are, for example, instruments equipped with forceps at the tip, used for various procedures such as biopsies to collect a portion of living tissue from within a body cavity, and excisions of lesions within a body cavity.

[0072] As shown in Figures 11 and 12, the instrument stand 50 is arranged to rotate freely in both forward and reverse directions in the direction of arrow R, with a support shaft 51 erected on the side portion 20b of the tip component 20 as the center of rotation. This instrument stand 50 is made of resin material.

[0073] The instrument lifting stand 50 is connected to the instrument operating lever 10 (see Figure 1) provided on the operating unit 3 via an instrument lifting operation wire 17. Here, the instrument lifting operation wire 17 is positioned from the tip 5, through the insertion part 2, to the inside of the operating unit 3.

[0074] The treatment instrument lifting operation wire 17 is made of a flexible, elongated linear member. The tip of the treatment instrument lifting operation wire 17 is connected to the treatment instrument lifting base 50 through a wire stopper 52 (see Figures 11 and 12). The wire stopper 52 is fixed to the tip of the treatment instrument lifting operation wire 17 by crimping. The wire stopper 52 is fixed to a part of the treatment instrument lifting base 50 closer to the front.

[0075] The treatment device lifting operation wire 17 is inserted so as to be able to move back and forth in the direction along its long axis within a treatment device lifting wire insertion conduit (not shown) which is positioned between the insertion part 2 and the operation part 3.

[0076] Here, the treatment tool lifting wire insertion conduit is positioned to pass through the inside of the insertion section 2 from the tip section 5 to the base end (inside the operating section 3). This treatment tool lifting wire insertion conduit has a flexible structure that can freely follow the bending or flexing movement of the insertion section 2. At the same time, the treatment tool lifting wire insertion conduit protects the outer surface of the treatment tool lifting operating wire 17 and ensures that the treatment tool lifting operating wire 17 moves smoothly back and forth inside the treatment tool lifting wire insertion conduit.

[0077] With this configuration, the instrument lifting stand 50 is driven in response to the operation input of the instrument operating lever 10 and rotates in a predetermined direction, so that the raising and lowering of the instrument relative to the tip 5 can always be performed smoothly.

[0078] The first cover 21 is a cover member positioned outside the tip component 20 and covering a portion of the outer surface of the tip component 20. The first cover 21 is made of a transparent resin material.

[0079] The first cover 21 is formed to cover the observation window 25a, the illumination window 26a, and the portion of the treatment instrument lifting stand 50 other than the lifting and tilting area and the treatment instrument protrusion area. In other words, the first cover 21 has an opening 21a to secure the treatment instrument protrusion area (see Figure 5, etc.).

[0080] The second cover 22 is positioned outside the tip component 20 and is a cover member that covers a portion of the outer surface of the tip component 20 that is different from the aforementioned portion. The second cover 22 is made of an opaque resin material.

[0081] The second cover 22 is a lid member that covers the opening 20r formed on the side of the area in the tip component 20 where the imaging unit 25 and the illumination unit 26 are arranged (see Figure 3, etc.).

[0082] The third cover, the fluid delivery nozzle 23, is positioned outside the tip component 20 and is a cover member that covers a portion of the outer surface of the tip component 20 that is different from the first cover 21 and the second cover 22. The fluid delivery nozzle 23 is made of a transparent resin material. The fluid delivery nozzle 23 is formed separately from the tip component 20 and is adhesively fixed to the tip component 20.

[0083] The fluid delivery nozzle 23 has a fluid ejection hole 23a that supplies a fluid such as liquid toward the outer surface of the observation window 25a (see Figure 13, etc.). The fluid ejection hole 23a is positioned higher than the observation window 25a. For this reason, the fluid ejection hole 23a is formed with a downward inclination angle (for example, an angle of about 13 to 15 degrees) so that the fluid is ejected toward the outer surface of the observation window 25a.

[0084] Here, the symbol [AN] shown in Figure 13 indicates the inclination angle of the liquid ejection direction F1 with respect to the horizontal line H extending from the fluid ejection hole 23a.

[0085] As shown in Figures 14 and 15, the fluid ejection hole 23a is connected to the fluid delivery pipeline 19 through the fluid pipeline 23b formed inside the fluid delivery nozzle 23 and the fluid pipeline 20c of the tip component 20. In this way, the fluid flow path F is formed.

[0086] In this case, the fluid delivery pipeline 19 is formed by a cylindrical connecting sleeve 19a and a fluid delivery tube 19b.

[0087] The cylindrical connecting sleeve 19a is a pipe member that connects the tip component 20 and the fluid delivery tube 19b. The fluid delivery tube 19b is inserted through the insertion section 2 from the tip section 5 to the operating section 3, and further inserted through the universal cable 4 to the scope connector 14.

[0088] Here, the inner surface of the fluid conduit 20c of the tip component 20 and the outer surface of the tip side of the cylindrical connecting sleeve 19a are bonded and fixed together around the entire circumference using, for example, a thermosetting adhesive (see reference numeral [Ad] in Figure 14). Also, the outer surface of the base end of the cylindrical connecting sleeve 19a and the inner surface of the tip of the fluid delivery tube 19b are bonded and fixed together around the entire circumference using, for example, a thermosetting adhesive (see reference numeral [Ad] in Figure 14). In this way, the tip component 20 and the fluid delivery conduit 19 are sealed together in a watertight manner.

[0089] The fluid delivery nozzle 23 is bonded and fixed to the tip component 20 by its back surface 23c and bottom surface 23d using, for example, a photocurable adhesive (third adhesive) (see reference numeral [Ad] in Figure 14).

[0090] Furthermore, the fluid delivery nozzle 23 is automatically bonded from the outside by a ring-shaped adhesive 24, as will be described later. In this way, the fluid delivery nozzle 23 is bonded and fixed from both the inside and the outside. In this manner, the space between the tip component 20 and the fluid delivery nozzle 23 is sealed in a watertight manner.

[0091] The ring-shaped adhesive 24 is a ring-shaped adhesive that covers a part of the outer surface of the tip component 20, the base end of the first cover 21, the base end of the second cover 22, the base end of the third cover, and the tip of the curved tube outer sheath tube 32, which will be described later (see Figures 10, 14, 19, 21, etc.). The ring-shaped adhesive 24 is formed by automatic bonding. A light-curing adhesive or the like is used for the ring-shaped adhesive 24.

[0092] The curved portion 6 is a component unit connected to the base end of the tip component 20 and configured to be actively bendable. The basic configuration of the curved portion 6 exemplified in this embodiment is substantially the same as that of conventional curved portions that are commonly used.

[0093] As shown in Figures 16 and 17, the curved section 6 includes a curved tube 30, a blade tube 31, a curved tube outer sheath tube 32, and a plurality (four in this example) of bending operation wires 33.

[0094] The curved tube 30 is a tubular member configured to be actively bendable in response to the bending operation of the bending operation knob 9, by connecting a plurality of bending sections (30a, 30b, 30c, 30d). Here, the plurality of bending sections include a tip section 30a, a first section 30b, a plurality of intermediate sections 30c, and a base section 30d. Although only five intermediate sections 30c are shown in the illustrated example, in actual endoscopes, it is common to connect about 10 of them. Each bending section is pivotally supported by a pivot pin 6a so as to be able to rotate relative to each other (see Figure 17).

[0095] The blade tube 31 covers the outer surface of the curved tube 30 and is a tubular member formed by shaping a metal mesh into a tubular form.

[0096] The curved tube sheath tube 32 is an elongated tubular member that covers the outer surface of the blade tube 31 and the front and rear ends of the curved tube 30. The front end of the curved tube sheath tube 32 is positioned closer to the base end than the base ends of the first cover 21 and the second cover 22. The base end of the curved tube sheath tube 32 is positioned closer to the base end than the front end of the flexible tube portion 7.

[0097] In this case, the outer surfaces between the tip of the curved tube sheath 32 and the base ends of the first cover 21, the second cover 22, and the fluid delivery nozzle 23 are covered all around with a ring-shaped adhesive 24 (see reference numeral [Ad] in Figure 19). This ensures a watertight seal between the tip component 20 and the curved tube sheath 32.

[0098] The outer surfaces near the base end of the curved tube sheath 32 and the tip end of the flexible tube section 7 are covered all around with a similar ring-shaped adhesive 24 (see reference numeral [Ad] in Figure 20). This ensures a watertight seal between the curved tube sheath 32 and the outer surface of the flexible tube section 7.

[0099] At the connection point between the curved section 6 and the flexible tube section 7, as shown in Figure 20, in addition to the ring-shaped adhesive 24 described above, the entire circumference between the inner circumferential surface on the base side of the base end piece 30d and the outer circumferential surface on the tip side of the tip end fitting 36 is bonded and fixed using, for example, a moisture-curing adhesive or a thermosetting adhesive (see reference numeral [Ad] in Figure 20).

[0100] Furthermore, depending on the material selected for the outer sheath tube 32 of the curved pipe, it is possible to further reduce the thickness of the outer sheath tube. Achieving a thinner outer sheath tube 32 can contribute to reducing the bending torque of the bending operation knob 9.

[0101] Here, as shown in Figure 20, the flexible tube section 7 is composed of a flexible tube outer sheath 34, a spiral tube 35, and a tip fitting 36.

[0102] The flexible tube outer sheath 34 is a multilayer tubular member formed by laminating, for example, an inner resin layer, a blade layer, and an outer rubber layer. The spiral tube 35 is a tubular member formed by spirally winding, for example, a flat plate material, and is flexible as a whole. The tip cap 36 is a substantially cylindrical shape disposed at the tip of the spiral tube 35 and is provided as a connecting member that connects the curved section 6 and the flexible tube section 7. The structure of the flexible tube section 7 itself is substantially the same as that applied to conventional endoscopes.

[0103] The multiple bending control wires 33 are composed of a wire core material 33a, a resin tube 33b, and a coil pipe 33c. Furthermore, the multiple bending control wires 33 are held inside the bending tube 30 by wire guides 6b, as shown in Figure 17. Wire guides 6b are generally provided for every multiple bending segments. The bending control wires 33 configured in this way are substantially the same as those used in conventional endoscopes.

[0104] As mentioned above, a portion of the outer surface of the tip component 20 and the base ends of the first cover 21, the second cover 22, and the third cover, and the tip of the curved tube outer sheath tube 32 are bonded and fixed together by an auto-bonding ring-shaped adhesive 24 around the entire circumference of the outer surface (see reference numeral [Ad] in Figures 19 and 21).

[0105] On the other hand, in the manufacturing process, the work of assembling the imaging unit 25, illumination unit 26, etc., into the tip component 20 is performed before attaching the second cover 22 to the tip component 20 and the first cover 21.

[0106] Specifically, first, the imaging unit 25, illumination unit 26, etc., are assembled into predetermined positions inside the tip component 20 through the opening 20r. After this assembly is complete, the second cover 22 is positioned to close the opening 20r and then fixed in place by adhesive (see reference numeral [Ad] in Figure 21).

[0107] At this time, as shown in Figure 21, the second cover 22 is bonded and fixed to three sides of the entire circumference of the opening 20r, excluding the base end side (for three-quarters of the circumference of the opening 20r), using, for example, a light-curing adhesive (the second adhesive) (see reference numeral [Ad] in Figure 21).

[0108] The base end of the opening 20r is similarly bonded and fixed with ring-shaped adhesive 24. Thus, the space between the tip component 20 and the second cover 22 is sealed in a watertight manner.

[0109] Here, as shown in Figures 7 to 9, Figure 21, etc., the first cover 21 has a first side 21x formed along the axial direction of the tip component 20. The second cover 22 has a second side 22x arranged along the first side 21x. The tip component 20 has a contact portion 20x formed along the axial direction of the tip component 20.

[0110] In this case, the contact portion 20x is arranged in a manner that it is sandwiched between the first side 21x and the second side 22x, as shown in Figure 8. At this time, the first side 21x and the second side 22x are positioned in contact with the contact portion 20x, respectively.

[0111] Here, the first side 21x and the second side 22x are bonded and fixed to the contact portion 20x using, for example, a light-curing adhesive (second adhesive) (see reference numeral [Ad] in Figures 8 and 9). In this way, the contact portion 20x of the tip component 20 and the first side 21x of the first cover 21, and the contact portion 20x of the tip component 20 and the second side 22x of the second cover 22 are sealed in a watertight manner.

[0112] Furthermore, as described above, the second cover 22 is adhesively fixed to the tip component 20 around the entire circumference of the opening 20r (see reference numeral [Ad] in Figure 21).

[0113] In this case, the third side 22y is defined as the edge that lies approximately parallel to the second side 22x and along the axial direction (the edge opposite the second side 22x) at the boundary between the tip component 20 and the second cover 22, within the entire circumference of the opening 20r of the second cover 22 (see Figures 8 and 9).

[0114] Furthermore, when the second cover 22 is positioned to close the opening 20r, the side on the tip component 20 side that is positioned opposite the third side 22y is designated as the fourth side 20y (see Figures 8 and 9).

[0115] In this case, as shown in Figure 9, the third side 22y of the second cover 22 has a cross-section that protrudes outward in the circumferential direction from the outer peripheral surface side. Also, the fourth side 20y of the tip component 20 has a cross-section that protrudes outward in the circumferential direction from the inner peripheral surface side.

[0116] Furthermore, the third side 22y and the fourth side 20y are arranged with their respective protruding portions facing each other, so that the protruding portions overlap in the radial direction. In this state, the boundary between the third side 22y and the fourth side 20y is bonded and fixed using, for example, a light-curing adhesive (see the reference numeral [Ad] in Figures 8 and 9). In this way, the space between the third side 22y of the second cover 22 and the fourth side 20y of the tip component 20 is sealed in a watertight manner.

[0117] In this embodiment, the front shape of the tip portion 5, when viewed from the front along the long axis, is formed as a substantially circular shape, as shown in Figure 8. This substantially circular shape is formed by the outer shapes of the first cover 21, the second cover 22, and the third cover, which is the fluid delivery nozzle 23, and a part of the outer shape of the tip component 20. The ring-shaped adhesive 24 has a substantially circular front shape that is concentric with the tip portion 5 and has a slightly larger diameter.

[0118] In this case, the tip component 20 has a radial projection 20e that protrudes radially outward in a part of the area where the imaging unit 25 is installed (see Figures 5, 7, 8, etc.). This radial projection 20e has a different shape from the substantially circular shape of the front surface of the tip component 5.

[0119] Therefore, in the endoscope tip of this embodiment, the radial projection 20e is set to be within the range of the maximum outer diameter of the ring-shaped adhesive 24 when the tip 5 is viewed from the front.

[0120] In other words, the radial projection 20e is configured not to protrude outward beyond the maximum outer diameter of the tip portion 5 (see Figures 5 and 8). This prevents the tip portion 5 from becoming larger in diameter and contributes to the reduction in the diameter of the endoscope tip.

[0121] In other words, in the tip portion 5 of this embodiment, each part of the fluid delivery nozzle 23, which is the tip component 20, the first cover 21, the second cover 22, and the third cover, that is covered by the ring-shaped adhesive 24 is formed to include a portion having the same radius of curvature (specifically, concentric arcs).

[0122] By the way, the attachment structure of the first cover 21 to the tip component 20 is as follows. Figures 22 and 23 mainly show the adhesive portion when attaching the first cover 21 to the tip component 20 in the endoscope tip of this embodiment, as well as the position-defining structure, rotation-suppressing structure, and removal-preventing structure between the two (20, 21).

[0123] As shown in Figure 22, the base end of the first cover 21 and the tip component 20 are bonded and fixed together using, for example, a moisture-curing adhesive (see reference numeral [Ad] in Figure 20). This ensures a watertight seal between the first cover 21 and the tip component 20.

[0124] Furthermore, the front surface of the tip component 20 and the inner front surface of the first cover 21 (base end side) are bonded and fixed together using, for example, a moisture-curing adhesive (see reference numeral [Ad] in Figure 22). As a result, the space between the first cover 21 and the tip component 20 (front side) is sealed in a watertight manner.

[0125] In this case, a position-regulating boss 20f is formed on the front surface of the tip component 20. Accordingly, a position-regulating hole 21b is formed on the inner front surface of the first cover 21.

[0126] Then, when attaching the first cover 21 to the tip component 20, the position regulating boss 20f is fitted into the position regulating hole 21b. This positions the first cover 21 in the longitudinal direction relative to the tip component 20.

[0127] At this time, the outer circumference of the side surface of the position-regulating boss 20f and the inner circumference of the position-regulating hole 21b are bonded and fixed together over the entire circumference using, for example, a moisture-curing adhesive (see reference numeral [Ad] in Figure 22).

[0128] Furthermore, a rotation-restricting block 20g is formed on a portion of the tip component 20 near the base end, protruding radially outward. Accordingly, a position-restricting notch 21c is formed on the base end of the first cover 21.

[0129] Then, when attaching the first cover 21 to the tip component 20, the position restricting notch 21c is fitted into the rotation restricting block 20g. This restricts the rotation of the first cover 21 attached to the tip component 20 around its long axis.

[0130] Furthermore, a so-called snap-fit ​​mechanism is provided for attaching the tip component 20 to the first cover 21. Specifically, a convex retaining portion 20h is formed on a part of the side surface of the tip component 20. Accordingly, a fitting retaining hole 21d is formed on a part of the side surface of the first cover 21.

[0131] Here, the convex holding portion 20h protrudes radially outward and has an inclined surface that extends radially inward from the apex of the protrusion toward the tip side. Here, the height dimension of the convex holding portion 20h (the dimension from the central axis of the tip component 20 to the apex surface of the convex holding portion 20h) is formed to be slightly larger than the radius dimension of the inner circumferential surface of the first cover 21. The fitting holding hole 21d has an area that can accommodate the convex holding portion 20h.

[0132] Then, when attaching the first cover 21 to the tip component 20, the first cover 21 is slid from the front side of the tip component 20 in a direction along the long axis. To do this, first, the inner surface of the side of the first cover 21 is brought into contact with the apex surface of the convex holding portion 20h, and the first cover 21 is moved toward the base end. As a result, the first cover 21 is pushed radially upward from the base end side by the convex holding portion 20h, against its own elastic force.

[0133] In this state, when the first cover 21 is advanced toward the base end in the direction along its long axis, the fitting retaining hole 21d eventually fits into the convex retaining portion 20h. At this time, the first cover 21 releases its own elastic force and returns to its normal state. Thus, the convex retaining portion 20h becomes fitted into the fitting retaining hole 21d. At this time, the axial movement of the first cover 21 is restricted relative to the tip component 20. Therefore, the first cover 21 is mechanically fixed to the tip component 20. This state is shown in Figure 23.

[0134] In this way, by providing a snap-fit ​​mechanism as a means of connecting the tip component 20 and the first cover 21, even if deterioration or damage occurs in the adhesive bonding portion, it is possible to prevent the first cover 21 from being removed and falling off from the tip component 20.

[0135] Furthermore, as shown in Figure 22, in the bonding portion between the tip component 20 and the base end of the first cover 21, adhesive cannot be applied, for example, in the area where the treatment tool lifting operation wire 17 extends. Therefore, the adhesive strength tends to weaken in such areas (areas where adhesive cannot be applied).

[0136] Therefore, in the endoscope tip of this embodiment, a ring-shaped adhesive 24 is formed from the outer surface even in areas where the adhesive strength is weak, thereby reinforcing the adhesion in those areas and ensuring adhesive strength around the entire circumference.

[0137] As described above, according to the above embodiment, the endoscope tip is composed of a tip component 20, a first cover 21, a second cover 22, a third cover 23, a bending portion 6, a bending tube outer sheath 32, and a ring-shaped adhesive 24.

[0138] In this case, the ring-shaped adhesive 24 is configured to cover a part of the outer surface of the tip component 20, the base end of the first cover 21, the base end of the second cover 22, the base end of the third cover 23, and the tip of the curved pipe outer sheath tube 32. Furthermore, the space between the tip component 20 and the three cover members (21, 22, 23) is sealed watertight with the second adhesive.

[0139] As described above, the endoscope tip of this embodiment is formed by dividing the cover member that covers the outer surface of the tip component 20 into three cover members (21, 22, 23), and the spaces between each cover member are bonded and fixed with adhesive to ensure a watertight seal.

[0140] Furthermore, a portion of the outer surface of the tip component 20, the base ends of the three cover members (21, 22, 23), and the tip of the curved pipe outer sheath tube 32 are bonded and fixed together using an automatic ring-shaped adhesive 24.

[0141] In this way, the individual component shapes can be simplified by dividing the cover member into sections. Therefore, this can contribute to reducing manufacturing costs.

[0142] Furthermore, the weakening of the watertight structure between components that may occur due to the division of the cover component can be mitigated by using adhesive at each boundary, thereby achieving the minimum necessary watertight structure. Such a configuration is particularly effective, for example, in single-use endoscopes designed for single-use applications.

[0143] Simultaneously, by using the ring-shaped adhesive 24, it becomes unnecessary to overlap the base ends of each cover member (21, 22, 23) and the tip of the curved tube outer sheath 32 in the radial direction, thus enabling further reduction in the diameter of the endoscope tip. Therefore, the insertability of the endoscope insertion section can be further improved.

[0144] Furthermore, the first side 21x of the first cover 21 and the second side 22x of the second cover 22 are positioned with the contact portion 20x of the tip component 20 in between, and the space between the first cover 21 (first side) and the contact portion 20x, and the space between the second cover 22 (second side) and the contact portion 20x are each sealed watertight with the second adhesive.

[0145] Furthermore, at the boundary between the third side 22y of the second cover 22 and the fourth side 20y of the tip component 20, protruding portions are provided that protrude circumferentially from each component, and these protruding portions are arranged to overlap radially, and are fixed by adhesive at the boundary. By adopting this configuration, a more reliable watertight structure can be achieved while suppressing an increase in the diameter of the tip component 5.

[0146] Furthermore, since the first cover 21 and the third cover 23 are made of transparent material, a light-curing adhesive can also be used for the bonding areas on the inside of each cover member (21, 23).

[0147] The second cover 22 is a lid that covers the lighting unit 26, which includes a light guide (a light guide bundle 15 made by bundling multiple PLGs 26b). Since it is made of an opaque material, it is possible to prevent unwanted illumination light from leaking out from the second cover 22.

[0148] Incidentally, as described above, the tip of the endoscope in this embodiment is equipped with a treatment instrument stand 50. This treatment instrument stand 50 basically has a configuration that is substantially the same as that of conventional side-view endoscopes and the like that are commonly used.

[0149] Here, the raised position and inverted position of the treatment instrument lifting stand 50 are regulated as follows. First, Figure 24 is a conceptual diagram showing the configuration of the raising position stopper mechanism of the treatment instrument lifting stand at the tip of the endoscope in Figure 2. Note that in Figure 24, the first cover is omitted from the illustration in order to clearly show the component units arranged inside the tip 5. Furthermore, the treatment instrument lifting stand 50 is shown with a solid line in the inverted position and with a dotted line in the raised position.

[0150] As shown in Figure 24, the raising position stopper mechanism of the treatment instrument raising stand 50 is composed of a raising position regulating surface 20k and a raising stand side contact surface 50a.

[0151] The raising position restricting surface 20k is part of the tip component 20 and is formed in a portion adjacent to the gap space 20a which is the movable range of the treatment instrument raising base 50. The raising position restricting surface 20k is a plane facing the tip side of the tip component 20 and is formed by a plane that is substantially perpendicular to the direction along the long axis of the tip 5.

[0152] The lifting base side contact surface 50a is a part of the treatment instrument lifting base 50 and is a plane formed as a convex portion that protrudes toward an adjacent lateral portion from the gap space 20a which is the movable range of the treatment instrument lifting base 50. The lifting base side contact surface 50a is positioned opposite the lifting position regulating surface 20k when the treatment instrument lifting base 50 is rotated around the support shaft 51 and raised.

[0153] Then, when the treatment instrument lifting stand 50 moves from the inverted position (solid line) to the raised position (dotted line), the contact surface 50a on the lifting stand side comes into contact with the raised position restricting surface 20k. This restricts the rotation of the treatment instrument lifting stand 50 in the raised direction.

[0154] Next, Figure 25 is a conceptual cross-sectional view showing the configuration of the inverted position stopper mechanism of the treatment instrument lifting platform at the tip of the endoscope in Figure 2. In Figure 25 as well, the treatment instrument lifting platform 50 is shown with a solid line in the inverted position and with a dotted line in the raised position.

[0155] As shown in Figure 25, the inversion position stopper mechanism of the treatment instrument lifting stand 50 is composed of an inversion position restricting surface 21e and a lifting stand side contact surface 50b.

[0156] The inversion position restricting surface 21e is part of the first cover 21 and is formed as a convex portion that protrudes inward at the tip end on the bottom side. The inversion position restricting surface 21e is a substantially horizontal plane.

[0157] The lifting base side contact surface 50b is a plane that is part of the treatment instrument lifting base 50 and is formed on the side opposite to the side where the treatment instrument receiving groove 50c is formed. The lifting base side contact surface 50b is a plane that is parallel to the inverted position regulating surface 21e when the treatment instrument lifting base 50 is placed in the inverted position.

[0158] Then, when the treatment instrument lifting stand 50 moves from the lifting position (see dotted line) to the inverted position (see solid line), the contact surface 50b on the lifting stand side comes into contact with the inverted position restricting surface 21e. This restricts the rotation of the treatment instrument lifting stand 50 in the inverted direction.

[0159] Incidentally, in the endoscope tip of this embodiment, the support shaft 51 and wire stopper 52 of the treatment instrument lifting base 50 have a mechanism to prevent them from being removed and falling off the treatment instrument lifting base 50.

[0160] First, Figure 26 is a cross-sectional view taken along the line

[26] -

[26] in Figure 24. That is, Figure 26 shows a cross-sectional view of the cutting plane including the axial center line of the support shaft 51, and illustrates the mechanism for preventing the support shaft 51 from being removed or falling out.

[0161] As described above, the support shaft 51 of the instrument lifting stand 50 is erected on the side portion 20b of the tip component 20. The instrument lifting stand 50 is rotatably supported on the support shaft 51.

[0162] When the first cover 21 is attached to the tip component 20 in this state, as shown in Figure 26, the side wall contact surfaces 21f of the first cover 21 are positioned opposite each other in a direction along the long axis of the support shaft 51.

[0163] The side wall contact surface 21f is a plane formed on a convex portion that protrudes inward from a part of the side wall surface of the first cover 21. The side wall contact surface 21f is positioned on the extension line in the direction along the long axis of the support shaft 51 and consists of a plane that is substantially perpendicular to the long axis.

[0164] With this configuration, when the first cover 21 is attached to the tip component 20, the support shaft 51's movement in the removal direction is restricted and prevented by the side wall contact surface 21f. Therefore, the removal and detachment of the support shaft 51 can be suppressed after the tip component 5 has been assembled.

[0165] Furthermore, Figure 27 is a cross-sectional view taken along the line

[27] -

[27] in Figure 24. That is, Figure 27 shows a cross-sectional view of the cut surface including the axial center line of the wire fastener 52, and illustrates the mechanism for preventing the wire fastener 52 from being removed or falling off.

[0166] As described above, the wire fastener 52 of the instrument lifting stand 50 is fixed to a part of the instrument lifting stand 50 closer to the tip. In this case, the wire fastener 52 is formed in a form in which two cylinders of different diameters are stacked in the axial direction and integrated. As a result, the wire fastener 52 has a stepped surface 52a.

[0167] The wire stopper 52 is then stored in the wire stopper storage section 50d of the treatment instrument lifting stand 50. The wire stopper storage section 50d has a through hole 50e into which the small-diameter portion 52b of the wire stopper 52 is inserted, and into which the treatment instrument lifting operation wire 17 is inserted.

[0168] The procedure for assembling the wire stopper 52 into the treatment instrument lifting stand 50 is as follows. First, the treatment instrument lifting operation wire 17 is inserted through the through hole 50e. Next, the wire stopper 52 is crimped and fixed to the tip of the treatment instrument lifting operation wire 17. Then, the wire stopper 52 is stored in the wire stopper storage section 50d. At this time, the small diameter portion 52b is inserted into the through hole 50e. With the treatment instrument lifting operation wire 17 pulled in the direction that the wire stopper 52 is stored in the wire stopper storage section 50d, the stepped surface 52a will eventually come into contact with the peripheral edge of the through hole 50e. At this time, the surface that the stepped surface 52a comes into contact with is the wire stopper position regulating surface 50f.

[0169] With this configuration, the stepped surface 52a comes into contact with the wire stopper position regulating surface 50f, thereby preventing the wire stopper 52 from being removed or falling off the treatment instrument lifting stand 50.

[0170] By the way, in the endoscope tip of this embodiment, as described above, a treatment instrument lifting stand 50 is provided on the tip component 20 of the tip 5, and a gap space 20a is formed to ensure the raising and lowering operation of the treatment instrument lifting stand 50.

[0171] The instrument lifting stand 50 is raised and lowered within the gap space 20a. At this time, both side surfaces of the instrument lifting stand 50 may slide against the side walls of the gap space 20a.

[0172] Taking this into consideration, as shown in Figures 11, 12, and 28, multiple linear projections 20aa are formed on both side walls (sliding surfaces) of the gap space 20a of the tip component 20, extending in the direction in which the treatment instrument lifting base 50 moves.

[0173] Here, Figure 28 shows the endoscope tip of Figure 2 with some components (first cover, treatment instrument stand, second cover) removed, and is a schematic perspective view from a different direction than Figure 11.

[0174] On the other hand, when the instrument lifting stand 50 is positioned at its maximum lifting position, there is a possibility that its tip portion may enter the imaging field of view of the imaging unit 25.

[0175] Therefore, in the endoscope tip of this embodiment, the shape of the tip portion of the treatment instrument lifting platform 50 is formed by cutting out a part of the side adjacent to the imaging unit 25.

[0176] Here, Figure 29 is a conceptual diagram showing the field of view V of the imaging unit when the treatment instrument lifting platform is in the raised position at the tip of the endoscope in Figure 2.

[0177] As shown in Figure 29, specifically, for example, a part of the tip of the treatment instrument lifting stand 50 has an inclined surface 50g that is oriented away from the side where the imaging unit 25 is located.

[0178] In this way, by forming an inclined surface 50g by cutting out a part of the movable member (treatment instrument lifting stand 50) that may enter the imaging field of view V, the imaging field of view V can be reliably secured.

[0179] Furthermore, such measures are not limited to the imaging field of view V of the imaging unit 25. For example, they are also an effective measure when a portion of the illumination light from the illumination unit 26 may be obstructed by a movable member (treatment instrument lifting stand 50), and can be applied in the same manner.

[0180] On the other hand, the configuration of the treatment instrument lifting operation wire 17, which contributes to the lifting and tilting operations of the treatment instrument lifting stand 50, and the attachment structure of the treatment instrument lifting operation wire 17 to the tip component 20, are basically substantially the same as those of conventional side-view endoscopes and the like that are commonly used.

[0181] Here, Figure 30 is a cross-sectional view showing the configuration of the treatment instrument raising operation wire and the attachment structure of the treatment instrument raising operation wire to the tip component at the endoscope tip of Figure 2. Note that in Figure 30, the cross-section is along the long axis of the endoscope tip and shows a cross-section corresponding to the position of the treatment instrument raising operation wire.

[0182] Figure 31 is a cross-sectional view taken along the line

[31] -

[31] in Figure 30 (Figure 35). Figure 32 is an enlarged perspective view schematically showing the shape of the base end surface of the tip component at the end of the endoscope in Figure 2. Figure 33 is an external perspective view of a portion of the treatment instrument lifting operation wire taken out at the end of the endoscope in Figure 2, viewed from a position closer to the base end. Figure 34 is an external perspective view of a portion of the treatment instrument lifting operation wire taken out at the end of the endoscope in Figure 2, viewed from a position closer to the tip end.

[0183] The treatment device lifting operation wire 17 is composed of a sleeve 17a, an inner sheath 17b, an outer sheath 17c, and a wire core material 17d.

[0184] The sleeve 17a is a connecting and fixing member for fixing the treatment tool lifting operation wire 17 to a predetermined part of the tip component 20. The sleeve 17a is formed in a substantially cylindrical shape using a material such as metal. An inner sheath 17b is inserted through the hollow through-hole of the sleeve 17a.

[0185] As shown in Figures 33 and 34, the sleeve 17a has a tapered surface 17aa and a flat surface 17ab on its outer surface.

[0186] The tapered surface 17aa is the portion that fits into the tapered portion 20ma (see Figures 30 and 32) within the rising wire insertion hole 20m (see Figures 30 to 32) of the tip component 20 when the sleeve 17a is inserted into the rising wire insertion hole 20m (see Figures 30 to 32) and positioned in a predetermined location. The tapered surface 17aa has a tapered shape in which the opening narrows from the base end to the tip end. In this case, the tapered portion 20ma functions as a positioning portion that defines the fitting position of the sleeve 17a in the axial direction.

[0187] When the sleeve 17a is positioned in the wire insertion hole 20m, the tapered surface 17aa and the tapered portion 20ma are bonded and fixed together around the entire circumference using, for example, a thermosetting adhesive (see reference numeral [Ad] in Figure 30). This ensures a watertight seal between the tapered surface 17aa of the sleeve 17a and the tapered portion 20ma of the wire insertion hole 20m of the tip component 20.

[0188] Furthermore, the lifting wire insertion hole 20m has a tapered shape in which the opening widens outward at the lifting wire tip opening 20mb (see Figures 11, 12, 30, etc.). This configuration allows for a simpler mold shape during the molding process of the tip component 20, thereby contributing to a reduction in manufacturing costs.

[0189] The flat portion 17ab is a plane formed by cutting out a part of the outer surface of the sleeve 17a (a so-called D-cut). The flat portion 17ab is formed to define the rotational direction when the sleeve 17a is inserted into the rising wire insertion hole 20m of the tip component 20. In this way, by providing the flat portion 17ab on the sleeve 17a, the assembly direction when inserting the sleeve 17a into the tip component 20 is defined. Therefore, incorrect assembly during the manufacturing process can be suppressed. Furthermore, by providing the flat portion 17ab, it is possible to contribute to reducing the diameter of the tip component 20 while ensuring the thickness of the outer surface of the rising wire insertion hole 20m of the tip component 20.

[0190] Furthermore, when the sleeve 17a is positioned in a predetermined location within the lifting wire insertion hole 20m, a relief hole 30ac (see Figure 31; also see Figure 36, etc., described later) is provided in the tip section 30a to avoid interference between a part of the outer surface of the sleeve 17a (flat section 17ab) and the inner surface of the tip section 30a in the curved section 6.

[0191] The inner sheath 17b is a resin tube that prevents bodily fluids from flowing in through the wire tip opening 20mb of the tip component 20, thereby ensuring watertightness and protecting the wire core material 17d. The outer sheath 17c is a protective sheath constructed, for example, using a coil pipe, to protect the outer surface of the inner sheath 17b. The wire core material 17d is a linear member made of a material such as metal.

[0192] Here, the inner surface of the outer sheath 17c and the outer surface of the inner sheath 17b are bonded together over the entire circumference using, for example, a thermosetting adhesive (see reference numeral [Ad] in Figure 30). This seals the outer sheath 17c and the inner sheath 17b in a watertight manner.

[0193] Similarly, the inner surface of the sleeve 17a and the outer surface of the inner sheath 17b are bonded together over the entire circumference using, for example, a thermosetting adhesive (see reference numeral [Ad] in Figure 30). This ensures a watertight seal between the sleeve 17a and the inner sheath 17b.

[0194] As shown in Figure 33, the outer diameter of the surface of the sleeve 17a that contacts the outer sheath 17c is set to be 80% or more of the outer diameter of the outer sheath 17c.

[0195] By the way, in the endoscope tip of this embodiment, the bending section 6 is basically the same as that of a conventionally constructed bending section, as described above. In the bending section 6 of this embodiment, for example, the connection configurations between the tip section 5 and the flexible tube section 7 have been simplified.

[0196] For example, the connection between the tip of the curved portion 6 and the base of the tip portion 5 is made by a fixing pin 37 and adhesive.

[0197] Here, Figure 35 is a cross-sectional view taken along the line

[35] -

[35] in Figure 31. Figure 36 shows the endoscope tip of Figure 2 with some components removed, and is a perspective view taken from a different direction than in Figure 11.

[0198] A pin insertion hole 30ab is formed in the tip section 30a of the curved portion 6 (see Figure 17, etc.). A fixing pin 37 is inserted through this pin insertion hole 30ab (see Figures 31, 35, 36, etc.). This fixing pin 37 is then fitted into the fitting hole 20p of the tip component 20 (see Figures 31, 35, 35, etc.).

[0199] At this time, the outer peripheral surface on the base end of the tip component 20 and the inner peripheral surface on the tip end of the tip piece 30a are bonded and fixed together using, for example, a moisture-curing adhesive (see reference numeral [Ad] in Figure 31).

[0200] It should be noted that the fixing pin 37 is not necessarily an essential component, and the connection between the tip of the curved portion 6 and the base of the tip portion 5 may be made solely by adhesive.

[0201] Furthermore, the tip piece 30a and the tip component 20 have a rotational position regulating mechanism for positioning the tip piece 30a at a predetermined position in the rotational direction relative to the tip component 20. As shown in Figure 36, this rotational position regulating mechanism is composed of a rectangular notch 30aa formed at the tip of the tip piece 30a and a rectangular protruding engaging portion 20n formed radially protruding from the base end side of the tip component 20.

[0202] When attaching the tip piece 30a to the tip component 20, the rotational orientation of the tip piece 30a relative to the tip component 20 can be defined by engaging the notch 30aa with the protruding engagement portion 20n. This also serves to restrict the rotation of the tip piece 30a in cases where the adhesion between the tip piece 30a and the tip component 20 deteriorates or breaks.

[0203] Furthermore, as shown in Figures 35 and 36, the axial positioning of the tip piece 30a is achieved by the tip surface 30ad of the tip piece 30a contacting the stepped surface 20q provided on the base end side of the tip component 20. For this purpose, the base end side of the tip component 20 has a small diameter portion that is approximately the same diameter as the inner diameter of the tip piece 30a when the tip piece 30a is connected, and a large diameter portion that is slightly larger in diameter than the small diameter portion. At this time, the outer diameter of the tip piece 30a is set to a dimension that does not exceed the outer diameter of the large diameter portion on the tip component 20 side. With this configuration, the position of the tip piece 30a in the longitudinal direction relative to the tip component 20 is defined.

[0204] On the other hand, the connection between the base end of the curved section 6 and the tip of the flexible tube section 7 is made with adhesive. Here, Figure 37 is a schematic perspective view showing the connection between the curved section and the flexible tube section 7 in the endoscope of Figure 1. Figure 38 is a cross-sectional view of the cut surface indicated by the arrow

[38] in Figure 37 (Figure 20). Figure 39 is an enlarged perspective view showing only the tip fitting included in the flexible tube section of Figure 37.

[0205] The base end of the base end piece 30d of the curved section 6 is positioned to cover the outer circumference of the tip end of the tip fitting 36 of the flexible tube section 7. In other words, the tip of the tip fitting 36 is inserted into the inside of the base end of the base end piece 30d. At this time, the inner surface of the base end of the base end piece 30d and the outer surface of the tip of the tip fitting 36 are bonded and fixed together over almost the entire circumference using, for example, a moisture-curing adhesive or a thermosetting adhesive (see reference numeral [Ad] in Figures 20 and 38).

[0206] Furthermore, the base end piece 30d and the tip end fitting 36 have a rotational position regulating mechanism for positioning the base end piece 30d of the curved section 6 at a predetermined position in the rotational direction relative to the tip end fitting 36 of the flexible tube section 7. As shown in Figure 37, this rotational position regulating mechanism is composed of a semicircular tongue-shaped portion 30da that protrudes in the longitudinal direction from the base end surface of the base end piece 30d, and a notch 36a formed by cutting out a semicircular part of the tip surface of the tip end fitting 36.

[0207] When attaching the base end piece 30d to the tip nozzle 36, the rotational orientation of the base end piece 30d relative to the tip nozzle 36 can be defined by engaging the tongue-shaped portion 30da with the notch 36a. This also serves to restrict the rotation of the base end piece 30d in cases where the adhesion between the base end piece 30d and the tip nozzle 36 deteriorates or breaks.

[0208] Furthermore, the axial positioning of the base end piece 30d is achieved by the tip surface of the base end piece 30d contacting the stepped surface 36b provided on the tip side of the tip jaw 36. For this purpose, as shown in Figure 39, when the base end piece 30d is connected to the tip side of the tip jaw 36, the tip jaw 36 has a small diameter portion 36c which is approximately the same diameter as the inner diameter of the base end piece 30d, and a large diameter portion 36d which is slightly larger in diameter than the small diameter portion 36c. At this time, the outer diameter of the base end piece 30d is set to a dimension that does not exceed the outer diameter of the large diameter portion 36d of the tip jaw 36. With this configuration, the position of the base end piece 30d in the longitudinal direction relative to the tip jaw 36 is defined.

[0209] Incidentally, in this embodiment of the endoscope, the configuration of the flexible tube section and the connection structure between the flexible tube section and the operating section are basically the same as those of conventional flexible tube sections, operating sections, etc.

[0210] Here, Figure 40 is a schematic perspective view showing the external appearance of the flexible tube section in the endoscope of this embodiment. Figure 41 is a cross-sectional view of the cross-section indicated by the arrow

[41] in Figure 40. Note that Figure 41 shows the connection structure between the flexible tube and the base end fitting in the flexible tube section of Figure 40. Figure 42 is an enlarged exploded perspective view of the main part showing the connection structure between the flexible tube section and the operating section of Figure 40. Figure 43 is a conceptual diagram showing the state in which each component unit (operating section and flexible tube section) is disassembled in the state of Figure 42. Figure 44 is a cross-sectional view of the cross-section indicated by the arrow

[44] in Figure 42.

[0211] For example, as shown in Figure 40, the flexible tube section 7 is composed of a tip fitting 36, a base fitting 38, and a flexible tube 39, etc. The tip fitting 36 is a connecting member connected to the base end of the curved section 6. The base fitting 38 is a connecting member connected to the tip of the operating section 3.

[0212] As shown in Figure 41, the flexible tube 39 is a tubular member consisting of a multilayer structure in which a flex 39a, a blade 39b, and an outer resin 39c are laminated. The flexible tube 39 is formed to have a predetermined degree of rigidity and flexibility.

[0213] Furthermore, multiple (generally two or four) bending operation wires 33 are inserted inside the flexible pipe section 7, as well as multiple conduit members such as treatment tool insertion conduits 18 and various signal wires (not shown) are inserted and arranged inside.

[0214] For example, the bending operation wire 33 is inserted through wire guides 33d that are fixedly arranged at predetermined intervals in the longitudinal direction, from the base end to the tip end 5 of the flexible tube section 7.

[0215] In the flexible tube section 7, the flexible tube 39 and the base end fitting 38 are fixed together with an adhesive. That is, the base end portion of the flexible tube 39 is fixed in a state where it is inserted inward from the tip opening 38a of the base end fitting 38. In this case, the outer circumferential surface of the base end portion of the flexible tube 39 and the inner circumferential surface of the tip opening 38a of the base end fitting 38 are bonded together using, for example, a light-curing adhesive (see reference numeral [Ad] in Figure 41). Therefore, the base end fitting 38 is formed of a transparent resin material.

[0216] Furthermore, a rotation restricting portion 3b is formed on a predetermined portion of the outer circumferential surface of the base end fitting 38, near the base end (see Figures 43, 44, etc.).

[0217] This rotation restricting portion 3b is formed at a predetermined location on the inner wall surface of the housing 3a of the operating portion 3. Correspondingly, the base end cap 38 is provided with an engaging portion 38b at the portion facing the rotation restricting portion 3b when the base end cap 38 is assembled into the housing 3a.

[0218] With this configuration, when the base end fitting 38 is assembled into the housing 3a of the operating unit 3, the rotational position of the base end fitting 38 relative to the operating unit 3 is restricted. This means that the rotation of the insertion unit 2 around its long axis relative to the operating unit 3 is restricted.

[0219] By the way, in the endoscope tip of the above-described embodiment, a fluid delivery nozzle 23 is formed separately as a third cover and is adhesively fixed to the tip component 20, but the configuration is not limited to this example.

[0220] For example, the fluid delivery nozzle 23 may be formed integrally with the tip component 20, and the third cover in the above-described embodiment may be omitted. Figure 45 shows an example of such a configuration. That is, Figure 45 is an exploded perspective view showing a schematic configuration of a modified endoscope tip of one embodiment of the present invention.

[0221] As shown in Figure 45, the tip portion 5 can be composed of a tip component 20, a first cover 21, and a second cover 22. By providing a ring-shaped adhesive 24 at the connection point between the tip portion 5 and the curved portion 6, an endoscope tip similar to that of the above-described embodiment can be constructed. Even with an endoscope tip of this configuration, the same operation and effects as those of the above-described embodiment can be obtained.

[0222] The present invention is not limited to the embodiments described above, and various modifications and applications can be implemented without departing from the spirit of the invention. Furthermore, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriate combinations of the multiple constituent elements disclosed. For example, if the problem that the invention aims to solve can be solved and the effects of the invention can be obtained even if some constituent elements are deleted from all the constituent elements shown in one embodiment, then the configuration with these deleted constituent elements can be extracted as an invention. Furthermore, constituent elements from different embodiments may be combined as appropriate. This invention is not limited by any particular embodiment other than being limited by the appended claims.

Claims

1. An endoscope tip comprising: a tip component having an observation window; a first cover disposed on the outside of the tip component and covering a part of the tip component; a second cover disposed on the outside of the tip component and covering a part of the tip component different from the part of the tip component; a curved portion connected to the base end side of the tip component; a tube covering the curved portion, with its tip portion positioned more base-side than the base ends of the first and second covers; and a ring-shaped adhesive covering a part of the outer surface of the tip component, the base end of the first cover, the base end of the second cover, and the tip portion of the tube.

2. The endoscope tip portion according to claim 1, characterized in that the first cover has a first side formed along the axial direction of the tip portion, and the second cover has a second side arranged along the first side.

3. The endoscope tip portion according to claim 2, characterized in that the first side and the second side are arranged to abut against the contact portion of the tip component formed along the axial direction.

4. The endoscope tip portion according to claim 3, characterized in that the first and second sides are fixed at the contact portion with a second adhesive.

5. The endoscope tip portion according to claim 4, characterized in that the boundary portion between the first cover or the second cover and the tip component, other than the first and second sides, is fixed with the second adhesive.

6. The endoscope tip according to claim 1, characterized in that the ring-shaped adhesive is a thermosetting adhesive.

7. The endoscope tip according to claim 1, characterized in that the ring-shaped adhesive is a photocurable adhesive.

8. The endoscope tip according to claim 1, characterized in that the first cover is made of a transparent material.

9. The endoscope tip according to claim 1, characterized in that the second cover is formed of an opaque material.

10. The endoscope tip of 9, characterized in that the second cover is a lid that covers the light guide.

11. The endoscope tip according to claim 1, characterized in that a gap is provided between the first cover and the tip component, and a treatment instrument lifting platform for changing the protruding direction of the treatment instrument is provided in the gap.

12. The endoscope tip portion according to claim 1, wherein it has a third cover disposed on the outside of the tip component and covering a portion different from the first cover and the second cover, and the ring-shaped adhesive covers the base end of the third cover.

13. The endoscope tip according to claim 12, characterized in that the third cover has a fluid ejection port for supplying fluid to the observation window.

14. The endoscope tip according to claim 12, characterized in that the third cover is formed of a transparent material.

15. The endoscope tip portion according to claim 12, characterized in that the third cover is fixed to the tip component by a second adhesive.

16. The endoscope tip portion according to claim 1, characterized in that each portion covered by the ring-shaped adhesive in the tip component, the first cover, and the second cover includes a portion having the same radius of curvature.

17. An endoscope comprising: a tip component having an observation window; a first cover disposed on the outside of the tip component and covering a part of the tip component; a second cover disposed on the outside of the tip component and covering a part of the tip component different from the part mentioned above; a curved portion connected to the base end of the tip component; a tube covering the curved portion and having its tip portion disposed at the base ends of the first cover and the second cover; and a ring-shaped adhesive covering a part of the outer surface of the tip component, the base end of the first cover, the base end of the second cover, and the tip of the tube.

18. A method for assembling the tip of an endoscope, comprising: the steps of: positioning the first cover so that its first edge contacts the contact portion of the tip component, thereby covering a portion of the outside of the tip component; positioning the second cover so that its second edge contacts the contact portion of the tip component, thereby covering a portion of the outside of the tip component different from the aforementioned portion; fixing the first edge of the first cover and the contact portion of the tip component with an adhesive; fixing the second edge of the second cover and the contact portion of the tip component with an adhesive; fixing the boundary portion between the first cover or the second cover and the tip component, other than the first and second edges, with the adhesive; and adhesively fixing the base end of the tip component, the base end of the first cover, the base end of the second cover, and the tip of the curved tube with a ring-shaped adhesive.

19. The method for assembling an endoscope according to claim 18, further comprising the steps of: positioning a third cover in a position that covers a portion of the tip component that is different from the first cover and the second cover on the outside of the tip component; fixing the third cover and the tip component with an adhesive; and fixing the base end of the third cover with a ring-shaped adhesive.

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