JP6187230B2 - Endoscope tip structure and manufacturing method thereof - Google Patents

Description

  The present invention relates to a distal end structure of an endoscope and a manufacturing method thereof.

In an endoscope widely used for diagnosis and surgery in a body cavity, the structure of the distal end portion that holds various parts and ensures waterproofness can be mentioned as a design feature.
In the distal end structure of a general endoscope shown in Patent Document 1, several fixing parts having a complicated shape are used at the distal end in order to hold an optical component or the like. The main optical parts are assembled to the fixing parts, and the use of an adhesive or sealing rubber is essential for waterproofing between the fixing parts.

Endoscopes include small-diameter endoscopes intended for use in a narrower space than general endoscopes. In Patent Document 2, in order to ensure waterproofness of the small-diameter endoscope, resin is injected into the distal end portion, and the gap between the components is filled with resin, thereby securing the components and securing waterproofness.
Further, as a method for holding a component other than using a resin or an adhesive, a heat shrinkable tube shown in Patent Document 3 can be cited. By using this tube as an exterior part of a small-diameter endoscope and reducing the diameter of the heat-shrinkable tube, it is possible to fix components in the tube.

JP-A-10-113326 Japanese Patent Laid-Open No. 9-238892 JP 2011-194137 A

However, in order to ensure the waterproofness of the distal end portion of the small-diameter endoscope, the fixing part having a complicated shape used in the general endoscope shown in Patent Document 1 has a small diameter. It is difficult to prepare it according to the requirements, and the manufacturing cost increases, which is not realistic.
The method of using a resin for securing waterproofness of a small-diameter endoscope shown in Patent Document 2 can ensure waterproofness when the amount of resin filling and curing are not sufficient when the endoscope is assembled. A failure occurs. In addition, fixing by filling with resin has a lower fixing strength than using fixing parts, and thus there is a high possibility that parts will fall off or be damaged during use. Furthermore, since the resin wraps around the lens surface during assembly, it is necessary to remove excess resin after assembly, which increases the cost of assembly.

Even if the method using the heat-shrinkable tube shown in Patent Document 3 is used for an endoscope, the rigidity of the tube increases after contraction, and thus the hardness of the entire endoscope increases. Therefore, there is a demerit that the operability of the endoscope is deteriorated, and it is not suitable for use as an outer tube of an endoscope.
Further, since the tube is contracted at a high temperature, a thermal load is applied to the internal optical fiber and electronic components.
Further, since the heat shrinkage of the heat shrinkable tube is plastic deformation, a tightening force that enhances waterproofness does not work after the heat shrinkage.
Since the tightening force does not work, as shown in Patent Document 3, a heat shrinkable tube is provided so as to cover a continuous portion in the order of the small diameter portion, the large diameter portion, and the small diameter portion along the axial direction of the endoscope. Otherwise, there is a problem that the heat-shrinkable tube that is hardened and stable after heat shrinkage shifts from the inside. Therefore, a large-diameter portion that protrudes in the radial direction must be disposed in the vicinity of the distal end surface of the endoscope, and the problem is that the distal end structure of the endoscope is increased in diameter relative to the diameter of the distal end surface. For example, the diameter of the distal end surface is smaller than the maximum diameter of the distal end structure of the endoscope, and there is a problem that the distal end surface on which the imaging light receiving surface and the illumination light emitting surface are arranged becomes small.

  The present invention has been made in view of the above-described problems in the prior art, and has a structure that is easy to assemble and has a simple structure, and has excellent parts fixing strength and waterproofness. It is an issue to provide.

The invention according to claim 1 for solving the above-described problems includes an imaging optical system, an illumination optical system including a plurality of optical fibers disposed on an outer periphery of the imaging optical system, the imaging optical system, and the illumination optics. A tube-shaped elastic body inserted into the hollow portion, the insert comprising the system,
A structure in which the outer diameter of the insert is larger than the distal end portion of the distal end portion relative to the distal end portion, or an inner diameter of the tubular elastic body at the distal end portion relative to the proximal end portion of the distal end portion Has a structure with a small diameter,
The insert is press-fitted into the tubular elastic body at the distal end portion, whereby the tubular elastic body clamps the insert with its elastic contraction force, and the outer surface of the imaging optical system and the inner surface of the illumination optical system The endoscope distal end structure is characterized in that the outer surface of the illumination optical system and the inner surface of the tubular elastic body are brought into close contact with each other.

The invention according to claim 2 is a light guide fiber bundle in which the illumination optical system has elasticity in a tube shape in which a plurality of optical fibers are bundled,
The imaging optical system is inserted into the hollow portion of the light guide fiber bundle,
The imaging optical system has a structure in which the outer diameter is large with respect to the proximal end portion from the distal end portion at the distal end portion,
The imaging optical system is press-fitted into the light guide fiber bundle at the distal end, whereby the light guide fiber bundle clamps the imaging optical system by its elastic contraction force, and the outer surface of the imaging optical system and the illumination optical system The distal end structure of the endoscope according to claim 1, wherein an inner surface of the endoscope is closely attached.

  According to a third aspect of the present invention, the imaging optical system includes a cylindrical component that holds an optical component on the inner periphery of the distal end portion, and the insert is inserted into the distal end portion according to the thickness of the cylindrical component. The distal end structure of an endoscope according to claim 1 or 2, wherein an outer diameter is larger than a portion closer to the base end side.

  The invention according to claim 4 is characterized in that the outer circumference and the inner circumference of the illumination optical system are concentric, and the center of the imaging optical system is arranged at the center of the endoscope. The endoscope distal end structure according to any one of Items 1 to 3.

  In the invention according to claim 5, the center of the inner periphery of the illumination optical system is unevenly distributed with respect to the center of the outer periphery, and the center of the imaging optical system is unevenly distributed from the center of the endoscope. The endoscope distal end structure according to any one of claims 1 to 3, wherein the endoscope has a distal end structure.

According to a sixth aspect of the present invention, there is provided an illumination optical system arranging step of arranging an illumination optical system comprising a plurality of optical fibers on the outer periphery of the imaging optical system, and an insert comprising the imaging optical system and the illumination optical system. A method of manufacturing an endoscope tip structure comprising an insertion step of inserting into a hollow portion of an elastic body,
Before the insertion step, the insert has a structure in which the outer diameter of the distal end portion is larger than the proximal end portion of the distal end portion or the tubular elastic body is proximal to the distal end portion of the distal end portion. A structure in which the inner diameter is small with respect to the portion, and the outer diameter of the insert at the tip is larger than the inner diameter of the tubular elastic body,
When the insertion step is performed, the insert is pressed into the tube-like elastic body at the distal end, so that the tube-like elastic body tightens the insert by its elastic contraction force, and the outer surface of the imaging optical system An endoscope distal end structure manufacturing method, wherein an inner surface of the illumination optical system, an outer surface of the illumination optical system, and an inner surface of the tubular elastic body are brought into close contact with each other.

The invention according to claim 7 comprises a structure in which the outer diameter of the insert is larger at the distal end than the proximal end of the distal end before the insertion step,
In carrying out the insertion step, the insert is inserted from its proximal end into the distal-end opening of the tubular elastic body, and at the end of the step, the insert is press-fitted into the tubular elastic body. The method for manufacturing the distal end structure of an endoscope according to claim 6.

The invention according to claim 8 constitutes a structure in which the inner diameter of the tubular elastic body is smaller than the proximal end portion of the distal end portion before the insertion step.
When the insertion step is performed, the insert is inserted from the distal end into the proximal end opening of the tubular elastic body, and the insert is pressed into the tubular elastic body at the distal end at the end of the step. The method for manufacturing the distal end structure of an endoscope according to claim 6.

The invention according to claim 9 is a light guide fiber bundle in which the illumination optical system has elasticity in a tube shape in which a plurality of optical fibers are bundled,
In the illumination optical system arrangement step, the imaging optical system is inserted into a hollow portion of the light guide fiber bundle,
Before the illumination optical system arrangement step, the imaging optical system has a structure in which the outer diameter of the distal end portion is larger than the proximal end portion of the distal end portion. A structure having a diameter larger than the inner diameter of the light guide fiber bundle,
When the illumination optical system arrangement step is performed, the imaging optical system is press-fitted into the light guide fiber bundle at the distal end, so that the light guide fiber bundle tightens the imaging optical system by its elastic contraction force, and the imaging 9. The method for manufacturing an endoscope tip structure according to claim 6, wherein an outer surface of the optical system and an inner surface of the illumination optical system are brought into close contact with each other.

  In carrying out the illumination optical system arrangement step, the imaging optical system is inserted from the proximal end into the distal end side opening of the light guide fiber bundle, and at the end of the step, 10. The method of manufacturing an endoscope distal end structure according to claim 9, wherein an imaging optical system is press-fitted into the light guide fiber bundle.

  According to the present invention, it is possible to easily assemble by press-fitting into an elastic tube body, and the press-fitting produces a tightening force to bring the parts into close contact with each other. The structure of the distal end portion of an endoscope having a good and simple structure and excellent component fixing strength and waterproofness can be obtained.

1A is a longitudinal sectional view of a distal end structure of an endoscope according to an embodiment of the present invention, and FIG. FIG. 2 is a longitudinal sectional view (a) and a front end view (b) of a distal end structure of an endoscope having an imaging optical system different from that of FIG. 1 according to the embodiment of the present invention. FIG. 6A is a view before press-fitting and FIG. 5B is a view after press-fitting showing a state in which a distal end portion of an imaging optical system is press-fitted into a light guide fiber bundle according to an embodiment of the present invention. FIG. 6A is a diagram before press-fitting and FIG. B is a diagram after press-fitting showing a state in which a distal end portion of an insert is press-fitted into a protective tube (tubular elastic body) according to an embodiment of the present invention. It is the table | surface which described the dimension of the structure 1 and the structure 2 which concern on the Example of this invention. It is a longitudinal cross-sectional view of the front-end | tip structure of the endoscope which concerns on other one Embodiment of this invention. It is a longitudinal cross-sectional view of the front-end | tip structure of the endoscope which concerns on other one Embodiment of this invention. FIG. 6A is a view before press-fitting and FIG. B is a view after press-fitting showing how the distal end portion of an insert is press-fitted into a protective tube (tubular elastic body) according to another embodiment of the present invention. It is a front end view of the front end structure of an endoscope concerning another embodiment of the present invention. It is a front end view of the front end structure of an endoscope concerning another embodiment of the present invention.

  An embodiment of the present invention will be described below with reference to the drawings. The following is one embodiment of the present invention and does not limit the present invention.

In the present embodiment, description will be made using the structure of a small-diameter endoscope. As shown in FIG. 1, the distal end structure of the endoscope of the present embodiment includes an imaging optical system 10 and an illumination optical system 20.
The imaging optical system 10 includes an image fiber 11 in which thousands of optical fibers are formed in a bundle shape, and a GRIN lens 12 that is closely fixed to the front end surface of the image fiber 11. The GRIN lens 12 serves as an imaging lens.
The illumination optical system 20 includes a light guide fiber bundle 21 in which several hundreds of optical fibers for propagating light from an illumination light source to an observation target are formed in a bundle shape. The exit end of the illumination light of the illumination optical system 20 is the end face 21 a of the light guide fiber bundle 21. That is, an optical component is not arranged in front of the end surface 21a, and the configuration is simple.
The light guide fiber bundle 21 is formed in a tube shape, and the imaging optical system 10 is disposed in the hollow portion.
A flexible protective tube 30 is provided outside the imaging optical system 10 and the illumination optical system 20 to protect contact between the living body and the optical component.
The light guide fiber bundle 21 and the protective tube 30 have elasticity suitable for press-fitting.

The imaging optical system 10 includes a lens frame 13 as a cylindrical component that holds optical components (the image fiber 11 and the GRIN lens 12) on the inside at the outer periphery of the distal end portion.

As shown in FIG. 1B, when the distal end of the endoscope is viewed from the front, the imaging optical system 10 is arranged at the center, and the illumination optical system 20 is arranged on the outer periphery of the imaging optical system 10. The illumination optical system 20 has a concentric outer periphery and inner periphery, and the center of the imaging optical system 10 is disposed at the center of the endoscope.
With the structure as described above, the endoscope can be reduced in diameter, and uniform illumination light can be irradiated to the field of view of the imaging optical system 10.

By fixing the GRIN lens 12 and the image fiber 11 in the lens frame 13, the adhesion between the GRIN lens 12 and the image fiber 11 is improved, and the GRIN lens 12 is dropped during use of the endoscope. Reduce. The lens frame 13 also has an effect of blocking stray light that enters the imaging optical system 10 from the illumination optical system 20 by reflection or scattering.
In order to block stray light, the periphery of the GRIN lens 12 may be painted black with black carbon or the like instead of the lens frame 13. Further, if all the side surfaces of the image fiber 11 are painted black, the light shielding effect is further improved.

A transparent adhesive is used for fixing between the GRIN lens 12 and the image fiber 11. The adhesive material may be a UV curable adhesive or an epoxy adhesive. In the case of a UV adhesive, the light can reach the adhesive when irradiated with UV light from the GRIN lens 12 side, and can be fixed by a simple method. In addition, since the epoxy adhesive is superior in strength to the UV adhesive, it has a high effect of preventing the lens from falling off during use.

The optical fiber constituting the image fiber 11 and the light guide fiber bundle 21 is made of multi-component glass, quartz glass, plastic (polymethyl methacrylate, polystyrene, styrene acrylonitrile, polyurethane, etc.) according to the use of transparency and color. Whichever you choose. Further, the diameter, NA, number, etc. of the optical fiber to be used may be arbitrarily selected within a range in which assembly is possible.
As shown in FIG. 2, the imaging optical system 10 may use a photoelectric element 14 used in an electronic endoscope or the like instead of the image fiber 11. The photoelectric element 14 can obtain a higher quality image than the image fiber. In FIG. 2, 15 is a base substrate of the photoelectric element 14, 16 is an electric cable for transmitting the driving power of the photoelectric element 14 and a video signal imaged by the photoelectric element 14, and 17 is an imaging lens combined with the photoelectric element 14.
The lens used in the imaging optical system 10 is not limited to a GRIN lens, and one or more spherical or aspherical lenses may be used as shown in FIG. By using a plurality of lenses, an imaging optical system with a wide viewing angle that is difficult to achieve with a GRIN lens can be configured.

Next, a mechanism that can secure the fixing strength and waterproofness between components at the distal end of the endoscope will be described.
As a manufacturing method, first, as shown in FIG. 3, an illumination optical system arrangement step of arranging an illumination optical system 20 composed of a plurality of optical fibers on the outer periphery of the imaging optical system 10 is performed. In the present embodiment, since the illumination optical system 20 is a tube-shaped light guide fiber bundle 21, the illumination optical system arrangement step inserts the imaging optical system 10 into the hollow portion of the light guide fiber bundle 21. To do.
Prior to the illumination optical system arrangement step, the imaging optical system 10 forms a structure in which the outer diameter of the distal end portion F is larger than that of the portion B closer to the proximal end than the distal end portion F. Furthermore, a structure is formed in which the outer diameter of the imaging optical system 10 at the distal end F is larger than the inner diameter of the light guide fiber bundle 21. That is, those having such an outer diameter and inner diameter are selected.
When the illumination optical system arrangement step is performed, the imaging optical system 10 is press-fitted into the light guide fiber bundle 21 at the distal end F, so that the light guide fiber bundle 21 tightens the imaging optical system 10 by its elastic contraction force, The outer surface of the imaging optical system 10 (in this embodiment, the outer surface of the lens frame 13) and the inner surface of the illumination optical system 20 (in this embodiment, the inner surface of the light guide fiber bundle 21) are brought into close contact with each other.

Further, when performing the present illumination optical system arrangement step, the imaging optical system 10 is inserted from its proximal end into the opening on the distal end side of the light guide fiber bundle 21, and the imaging optical system 10 is written at the distal end F at the end of this step. Press fit into the guide fiber bundle 21. When inserted in reverse, it is press-fitted from the beginning, so that it is press-fitted over the entire length while the friction force caused by the press-fitting is generated, and it is difficult to assemble.
As shown in FIG. 3 (b), an insert 40 including the imaging optical system 10 and the illumination optical system 20 is configured by this illumination optical system arrangement step. The insert 40 with respect to the protective tube 30 including the imaging optical system 10 and the illumination optical system 20 has a larger outer diameter at the distal end portion F than the distal end portion F relative to the proximal end portion B due to the thickness of the lens frame 13. It has become diameter.

When the light guide fiber bundle 21 is put around the lens frame 13 by the above-described illumination optical system arrangement process, the outer diameter of the lens frame 13 and the inner diameter of the bundle 21 are press-fitted and fitted as shown in FIG. Thus, the outer diameter of the bundle 21 is slightly increased. Since the bundle 21 has a structure that is elastically expanded by the lens frame 13, pressure is applied to the gap between the lens frame 13 and the bundle 21. Since the adhesiveness is improved by this pressure, the fixing strength and waterproofness of the components are improved.
If the outer peripheral edge of the base end side of the lens frame 13 is formed into a tapered shape (including a conical shape or a shape having a bulge or a depression in the longitudinal section), the lens frame 13 is reduced. When the light guide fiber bundle 21 is covered with the light guide fiber bundle 21, the assembly work can be performed smoothly, and the risk of damaging the light guide fiber bundle 21 can be suppressed.

After the illumination optical system arranging step, as shown in FIG. 4, the insertion step of inserting the insert 40 composed of the imaging optical system 10 and the illumination optical system 20 into the hollow portion of the protective tube 30 that is a tubular elastic body is performed. To do.
As described above, the insertion optical system has a structure in which the outer diameter of the insert 40 is larger at the distal end portion F than the distal end portion F at the proximal end side by the illumination optical system arrangement step. Thus, a structure in which the outer diameter of the insert 40 at the distal end F is larger than the inner diameter of the protective tube 30 has already been configured. In other words, the protective tube 30 having such an inner diameter is selected and this insertion process is performed.
At the time of carrying out this insertion process, the insert 40 is press-fitted into the protective tube 30 at the distal end F, so that the protective tube 30 clamps the insert 40 by its elastic contraction force, and the outer surface of the imaging optical system 10 (in this embodiment). The outer surface of the lens frame 13 and the inner surface of the illumination optical system 20 (in the present embodiment, the inner surface of the light guide fiber bundle 21) and the outer surface of the illumination optical system 20 (the outer surface of the light guide fiber bundle 21 in this embodiment) and protection. The inner surface of the tube 30 is brought into close contact.

  In carrying out this insertion step, the insert 40 is inserted from its proximal end into the opening on the distal end side of the protective tube 30, and the insert 40 is press-fitted into the protective tube 30 at the distal end F at the end of this step. When inserted in reverse, it is press-fitted from the beginning, so that it is press-fitted over the entire length while the friction force caused by the press-fitting is generated, and it is difficult to assemble.

When the protective tube 30 is put on the periphery of the light guide fiber bundle 21 by the above insertion process, as shown in FIG. 4B, protection is achieved by press-fitting the outer diameter of the bundle 21 and the inner diameter of the protective tube 30. The outer diameter of the tube 30 is slightly increased. Since the protective tube 30 has a structure that is spread by the bundle 21, pressure is applied to the gap between the bundle 21 and the protective tube 30, and the pressure applied to the gap between the bundle 21 and the lens frame 13 is further improved. Therefore, high adhesion is ensured in the gaps between the components, and an endoscope distal end structure having a simple structure and high fixing strength and waterproofness can be produced.

Since the light guide fiber bundle 21 and the protective tube 30 have a structure that can be expanded by press-fitting during assembly, it is desirable to use a material having appropriate stretchability. Typical materials for the light guide fiber bundle 21 having an appropriate stretchability include polymethyl methacrylate, polystyrene, styrene acrylonitrile, polyurethane and the like.
Typical materials for the protective tube 30 include nylon, Teflon (registered trademark), silicon, polyethylene, polystyrene, polyurethane, polypropylene, PEEK, and the like.

〔Example〕
In order to ensure high adhesion, the dimension of the lens frame 13, the dimension of the light guide fiber bundle 21, and the dimension of the protective tube 30 (before assembly) partially overlap in the radius range as will be described below. It is desirable that The overlap of dimensions will be described using Configuration 1 shown in the table shown in FIG.
When the outer diameter of the lens frame 13 corresponding to the outermost side of the imaging optical system 10 is 0.51 mm and the inner diameter of the light guide fiber bundle 21 corresponding to the innermost side of the illumination optical system 20 is 0.49 mm, the outer diameter of the lens frame 13 is the light guide. Since it is slightly larger than the inner diameter of the fiber bundle 21, as shown in FIG. 3, when the lens frame 13 is inserted into the light guide fiber bundle 21, the bundle 21 is slightly expanded to improve the adhesion between components. The tightening margin at that time is 0.02 mm.
The outer diameter of the light guide fiber bundle 21 that is the outermost side of the illumination optical system 20 is 0.67 mm, and the inner diameter of the protective tube 30 is 0.66 mm. The light guide fiber bundle 21 has a tightening margin of 0.02 mm due to the insertion of the lens frame 13, and the outer diameter of the bundle 21 is increased to 0.69 mm. Then, as shown in FIG. 4, when the light guide fiber bundle 21 is inserted into the protective tube 30, the protective tube 30 is slightly expanded to improve the adhesion between components. In this case, the interference is 0.03 mm. The close contact between the components due to the tightness secures the sealing performance at the distal end portion of the endoscope.
Further, as an example of dimensions different from those of the configuration 1, the same effect can be obtained even if the dimensional relationship is the configuration 2 shown in the table shown in FIG.

When the lens frame 13 is made of stainless steel, the optical fiber constituting the light guide fiber bundle 21 is made of acrylic, the protective tube 30 is made of nylon, and the parts are made according to the above dimensions. Leakage did not occur even for negative pressure of about MPa. The waterproofness of a general endoscope is designed so that it does not leak against a negative pressure of about 0.1 MPa during a leak test. It was.
As described above, it is possible to easily and accurately construct the distal end structure of a small-diameter endoscope having an outer diameter of less than 1 mm and excellent waterproofness.

[Other Embodiments]
Next, another embodiment obtained by modifying the above-described embodiment will be described. Similar parts are denoted by common reference numerals and description thereof is omitted.
The tip of the imaging optical system 10 is the same even if an optical system in which the diameter of the GRIN lens 12A is larger than the diameter of the image fiber 11 as shown in FIG. 6 is used instead of using a lens frame to increase the diameter of the tip. An effect is obtained.
In this case, the GRIN lens 12A can be formed by forming the outer peripheral edge of the base end side of the lens 12A into a tapered shape (including a conical shape and a bulging or concave shape in the longitudinal section). When the light guide fiber bundle 21 is put on, the work can be performed smoothly, and the risk of damaging the lens 12A and the light guide fiber bundle 21 can be suppressed.

As shown in FIG. 7 instead of the diameter of the imaging optical system 10, heat is applied to the tip of the light guide fiber bundle 21 to melt the fiber to form a molten mass 21 b, and the tip is expanded at the tip F to expand the diameter. You may comprise the structure where the diameter of the illumination optical system 20 was enlarged with respect to the part B of the base end side rather than F. FIG.

As described above, adopting a structure that increases the outer diameter of the insert 40 as a whole in the imaging optical system 10 and / or the illumination optical system 20 at the distal end F is a measure for sealing the distal end F by press-fitting. It is.
As another measure, as shown in FIG. 8, a small inner diameter portion 30 a may be formed at the distal end portion of the protective tube 30. In other words, the protective tube 30 employs a structure in which the inner diameter of the distal end portion F is smaller than the proximal end portion B of the distal end portion F.
As a manufacturing method, before the insertion step, the protective tube 30 has a structure in which the inner diameter is smaller than the portion B on the proximal end side with respect to the distal end F at the distal end F, and the insert 40 in the distal end F is formed. A structure in which the outer diameter is larger than the inner diameter of the protective tube 30 (inner diameter small diameter portion 30a) is implemented.
In this case, when the insertion step is performed, the insert 40 is inserted from the distal end thereof into the proximal end opening of the protective tube 30, and the insert 40 is inserted at the distal end F at the end of the present step into the small inner diameter portion 30 a of the protective tube 30. Press fit into.

On the other hand, the cross-sectional structure perpendicular to the axis of the endoscope may adopt a structure in which the illumination optical system 20 is unevenly arranged on only one side of the imaging optical system 10 as shown in FIG. 9 or FIG. In the structure shown in FIG. 10, the illumination optical system 20 includes a plurality of thick optical fibers 22, 22,... Bundled with a sealing material 23, and is disposed adjacent to the imaging optical system 10. Is done.
In this structure, the illumination optical system 20 is unevenly distributed with respect to the center A1 of the outer periphery thereof and the center A2 of the inner periphery thereof, and the center A2 of the imaging optical system 10 is unevenly distributed from the center A1 of the endoscope. Has been. Even with such a structure, it is possible to secure the waterproof property by press-fitting at the tip portion for sealing. Further, even within the same diameter, a thick fiber can be arranged as in the structure shown in FIG.

  The press-fitting into the light guide fiber bundle 21 and the press-fitting into the protective tube 30 for fixing and holding the components and sealing between the components at the tip F described above may be carried out, or the press-fitting into the protective tube 30 may be performed. May only be implemented. When only the press-fitting to the protective tube 30 is performed, the illumination optical system 20 does not need to be a tube-like one capable of performing the press-fitting like the light guide fiber bundle 21. However, it is preferable that the illumination optical system 20 has appropriate elasticity so that the degree of adhesion is increased by tightening from the outside by the protective tube 30.

DESCRIPTION OF SYMBOLS 10 Image pick-up optical system 11 Image fiber 12 GRIN lens 12A GRIN lens 13 Lens frame 14 Photoelectric element 20 Illumination optical system 21 Light guide fiber bundle 21a Outlet end faces 22, 22, Optical fiber 23 for illumination Sealing material 30 Protective tube (Tube-like elastic body )
30a Inner diameter small diameter part 40 Insert F Tip part

Claims (10)

An imaging optical system, an illumination optical system composed of a plurality of optical fibers disposed on the outer periphery of the imaging optical system, and a tube-like elasticity in which an insert made of the imaging optical system and the illumination optical system is inserted into a hollow portion With body,
A structure in which the outer diameter of the insert is larger than the distal end portion of the distal end portion relative to the distal end portion, or an inner diameter of the tubular elastic body at the distal end portion relative to the proximal end portion of the distal end portion Has a structure with a small diameter,
The insert is press-fitted into the tubular elastic body at the distal end portion, whereby the tubular elastic body clamps the insert with its elastic contraction force, and the outer surface of the imaging optical system and the inner surface of the illumination optical system And a distal end structure of an endoscope, wherein the outer surface of the illumination optical system and the inner surface of the tubular elastic body are brought into close contact with each other. The illumination optical system is a light guide fiber bundle having elasticity in a tube shape in which a plurality of optical fibers are bundled,
The imaging optical system is inserted into the hollow portion of the light guide fiber bundle,
The imaging optical system has a structure in which the outer diameter is large with respect to the proximal end portion from the distal end portion at the distal end portion,
The imaging optical system is press-fitted into the light guide fiber bundle at the distal end, whereby the light guide fiber bundle clamps the imaging optical system by its elastic contraction force, and the outer surface of the imaging optical system and the illumination optical system The endoscope distal end structure according to claim 1, wherein the inner surface of the endoscope is in close contact.   The imaging optical system includes a cylindrical component that holds an optical component on the inner periphery of the distal end portion, and the insert is positioned relative to the proximal end portion of the distal end portion from the distal end portion depending on the thickness of the cylindrical component. The endoscope distal end structure according to claim 1 or 2, wherein the outer diameter is increased.   The outer circumference and the inner circumference of the illumination optical system are concentric, and the center of the imaging optical system is disposed at the center of the endoscope. The endoscope front-end | tip structure as described in any one.   The illumination optical system is characterized in that the center of the inner periphery of the illumination optical system is deviated from the center of the outer periphery, and the center of the imaging optical system is deviated from the center of the endoscope. The distal end structure of the endoscope according to any one of claims 1 to 3. An illumination optical system arrangement step of arranging an illumination optical system composed of a plurality of optical fibers on the outer periphery of the imaging optical system, and an insert made of the imaging optical system and the illumination optical system is inserted into the hollow portion of the tubular elastic body A method of manufacturing an endoscope tip structure comprising an insertion step,
Before the insertion step, the insert has a structure in which the outer diameter of the distal end portion is larger than the proximal end portion of the distal end portion or the tubular elastic body is proximal to the distal end portion of the distal end portion. A structure in which the inner diameter is small with respect to the portion, and the outer diameter of the insert at the tip is larger than the inner diameter of the tubular elastic body,
When the insertion step is performed, the insert is pressed into the tube-like elastic body at the distal end, so that the tube-like elastic body tightens the insert by its elastic contraction force, and the outer surface of the imaging optical system A method for manufacturing a distal end structure of an endoscope, wherein the inner surface of the illumination optical system, the outer surface of the illumination optical system, and the inner surface of the tubular elastic body are brought into close contact with each other. Before the insertion step, the insert constitutes a structure having a large outer diameter with respect to the proximal end portion of the distal end portion relative to the distal end portion,
In carrying out the insertion step, the insert is inserted from its proximal end into the distal-end opening of the tubular elastic body, and at the end of the step, the insert is press-fitted into the tubular elastic body. The method for manufacturing an endoscope tip structure according to claim 6. Before the insertion step, the tubular elastic body constitutes a structure in which the inner diameter is smaller than the proximal end portion of the distal end portion relative to the distal end portion,
When the insertion step is performed, the insert is inserted from the distal end into the proximal end opening of the tubular elastic body, and the insert is pressed into the tubular elastic body at the distal end at the end of the step. The method for manufacturing an endoscope tip structure according to claim 6. The illumination optical system is a light guide fiber bundle having elasticity in a tube shape in which a plurality of optical fibers are bundled,
In the illumination optical system arrangement step, the imaging optical system is inserted into a hollow portion of the light guide fiber bundle,
Before the illumination optical system arrangement step, the imaging optical system has a structure in which the outer diameter of the distal end portion is larger than the proximal end portion of the distal end portion. A structure having a diameter larger than the inner diameter of the light guide fiber bundle,
When the illumination optical system arrangement step is performed, the imaging optical system is press-fitted into the light guide fiber bundle at the distal end, so that the light guide fiber bundle tightens the imaging optical system by its elastic contraction force, and the imaging The method for manufacturing the distal end structure of an endoscope according to any one of claims 6 to 8, wherein an outer surface of the optical system and an inner surface of the illumination optical system are brought into close contact with each other.   In carrying out the illumination optical system arrangement step, the imaging optical system is inserted from its proximal end into the distal end opening of the light guide fiber bundle, and at the end of the step, the imaging optical system is inserted into the light guide fiber at the distal end portion. The method for manufacturing an endoscope distal end structure according to claim 9, wherein the endoscope is press-fitted into a bundle.

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