JP2017146357A - Hollow optical fiber, endoscope device, and method of manufacturing hollow optical fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hollow optical fiber that is usable as an optical waveguide for an infrared laser, and also flexibly and reversibly bent, and further has a metal layer hardly peeled, and an endoscope device comprising the hollow optical fiber.SOLUTION: A hollow optical fiber according to one embodiment of the present invention comprises a tubular base material layer, a metal layer laminated on an inner surface of the base material layer, and a dielectric layer laminated on an inner surface of the metal layer and transmitting infrared light, the base material layer consisting principally of a methyl pentene polymer, and the metal layer consisting principally of silver. An endoscope device according to another embodiment of the present invention is an endoscope comprising a tubular insert part which is inserted into an analyte and an operation part arranged on a base end side of the insert part, and comprises a laser light guide module which can be inserted into the insert part, and a light source configured to emit infrared laser light to the laser light guide module, which comprises the hollow optical fiber.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a hollow optical fiber, an endoscope apparatus, and a method for manufacturing a hollow optical fiber.

  Infrared lasers with a wavelength of 1 μm or more have photon energy at the same level as the binding energy of biomolecules. Therefore, spectroscopic identification of biomolecules and selective removal of living cells by absorbing specific photons into molecules and decomposing the molecules. It is used for such applications.

  When an infrared laser is used in such a medical field, an optical waveguide that can be flexibly bent is required to introduce the infrared laser into a living body. As such an optical waveguide, a metal pipe made of phosphor bronze or stainless steel or a non-metal pipe made of fluororesin or quartz glass is used as a base material layer, and a metal layer and a dielectric layer are formed on the inner surface of the base material layer. Has been proposed (see Japanese Patent Laid-Open No. 2002-71973). In this conventional hollow optical fiber, by laminating a metal layer and a dielectric layer, the light reflected by the metal layer and the light reflected by the dielectric layer cause interference of each other, which reflects the infrared laser. The rate is increasing.

Japanese Patent Laid-Open No. 2002-71973

  However, among the conventional hollow optical fibers described above, the hollow optical fiber having a metal pipe as a base material layer cannot be restored reversibly after being bent. For this reason, it is difficult to recover the hollow optical fiber after being bent and introduced into the living body. Moreover, since the hollow optical fiber which uses the pipe comprised with quartz glass as a base material layer may fracture | rupture, it is difficult to use it with a bending radius of 1 cm or less. For this reason, the range which can be processed in the living body is restricted. Further, a hollow optical fiber having a pipe made of a fluororesin as a base material layer has low adhesiveness with a metal layer, and the metal layer is easily peeled off, so that the reliability is low. From the above, the conventional hollow optical fiber has room for improvement when any base material layer is used.

  The present invention has been made based on the circumstances as described above, and can be used as an optical waveguide of an infrared laser, is flexibly and reversibly bent, and a hollow optical fiber whose metal layer is difficult to peel off, a manufacturing method thereof, And it aims at provision of an endoscope apparatus provided with this hollow optical fiber.

  In response to the above problems, the inventors can use methylpentene polymer as the main component of the base material layer, and by improving the adhesion between the base material layer and the metal layer by surface-treating the inner surface of the base material layer, It has been found that a hollow optical fiber that can be flexibly and reversibly bent can be obtained.

  That is, the hollow optical fiber according to one embodiment of the present invention includes a tubular base material layer, a metal layer laminated on the inner surface of the base material layer, laminated on the inner surface of the metal layer, and transmits infrared light. A hollow optical fiber comprising a dielectric layer, wherein the base material layer is mainly composed of methylpentene polymer and the metal layer is composed mainly of silver.

  An endoscope apparatus according to another aspect of the present invention is an endoscope apparatus that includes a tubular insertion portion that is inserted into a subject, and an operation portion that is disposed on a proximal end side of the insertion portion. And a laser light guide module that can be inserted into the insertion portion, and a light source configured to emit an infrared laser to the laser light guide module. Or the hollow optical fiber of Claim 3 is provided.

  According to still another aspect of the present invention, a method for producing a hollow optical fiber includes a step of forming a tube-shaped base layer mainly composed of a methylpentene polymer by an extrusion molding method, and a plasma treatment of the inner surface of the base layer. A step of forming a metal layer on the inner surface of the base material layer by electroless silver plating, and a step of forming a dielectric layer capable of transmitting infrared light on the inner surface of the metal layer.

  The hollow optical fiber of the present invention can be used as an optical waveguide of an infrared laser, is flexibly and reversibly bent, and further, the metal layer is hardly peeled off. Therefore, the hollow optical fiber of the present invention is suitably used as a hollow optical fiber for an endoscope apparatus. In addition, the method for producing a hollow optical fiber of the present invention can make a hollow optical fiber that can be bent flexibly and reversibly while making it difficult to peel off the metal layer.

It is typical sectional drawing of the hollow optical fiber of one Embodiment of this invention. 1 is a schematic side view of an endoscope apparatus according to an embodiment of the present invention.

[Description of Embodiment of the Present Invention]
A hollow optical fiber according to one embodiment of the present invention includes a tubular base material layer, a metal layer laminated on an inner surface of the base material layer, and an inner surface of the metal layer, and capable of transmitting infrared light. A hollow optical fiber comprising a dielectric layer, wherein the main component of the base material layer is a methylpentene polymer, and the main component of the metal layer is silver.

  In the hollow optical fiber, since the main component of the metal layer is silver, a metal layer having high flatness, that is, less diffuse reflection can be formed on the inner surface of the base material layer. For this reason, the hollow optical fiber causes light interference such that light reflected by the metal layer and light reflected by the dielectric layer mutually intensify, and the reflectance of the infrared laser can be increased. The hollow optical fiber can be bent flexibly and reversibly because the main component of the base material layer is methylpentene polymer. Furthermore, since the said hollow optical fiber has comparatively high adhesiveness of a base material layer and a metal layer, it can make it difficult to peel off the metal layer laminated | stacked on the inner surface of a base material layer. Therefore, the hollow optical fiber can be used as an optical waveguide of an infrared laser, bends flexibly and reversibly, and the metal layer is hardly peeled off.

  The main component of the dielectric layer is preferably a cyclic olefin polymer or silver iodide. Since the cyclic olefin polymer has a refractive index of 1.45 or more and 1.55 or less, a hollow optical fiber having a small transmission loss can be formed. Moreover, since silver iodide has low reactivity with the base material layer, it is possible to suppress deterioration with time of the hollow optical fiber.

  The arithmetic average roughness Ra of the inner surface of the metal layer is preferably 10 μm or less. By setting the arithmetic average roughness Ra of the inner surface of the metal layer to 10 μm or less, the reflectance of the infrared laser can be further increased.

  An endoscope apparatus according to another aspect of the present invention is an endoscope apparatus that includes a tubular insertion portion that is inserted into a subject, and an operation portion that is disposed on a proximal end side of the insertion portion. A laser light guide module that can be inserted into the insertion portion; and a light source configured to emit an infrared laser to the laser light guide module. The laser light guide module includes the hollow optical fiber.

  The endoscope apparatus can be inserted with a laser light guide module including the hollow optical fiber. The hollow optical fiber is bent flexibly and reversibly, and the metal layer 2 is hardly peeled off. Therefore, the endoscope apparatus can suitably use an infrared laser in the medical field by using the hollow optical fiber as an infrared laser waveguide.

  According to still another aspect of the present invention, a method for producing a hollow optical fiber includes a step of forming a tube-shaped base layer mainly composed of a methylpentene polymer by an extrusion molding method, and a plasma treatment of the inner surface of the base layer. A step of forming a metal layer on the inner surface of the base material layer by electroless silver plating, and a step of forming a dielectric layer capable of transmitting infrared light on the inner surface of the metal layer.

  In the method for producing the hollow optical fiber, the main component of the base material layer is methylpentene polymer, so that a hollow optical fiber that can be flexibly and reversibly bent can be produced. Further, in the method for producing the hollow optical fiber, since the adhesion between the base material layer and the metal layer can be improved by plasma-treating the inner surface of the base material layer, the metal layer laminated on the inner surface of the base material layer is hardly peeled off. it can. Furthermore, the method for producing the hollow optical fiber includes a step of forming a metal layer mainly composed of silver and a dielectric layer capable of transmitting infrared light on the inner surface side of the base material layer. The interference of the light that intensifies the light to be reflected and the light reflected by the dielectric layer is generated, and the reflectance of the infrared laser of the manufactured hollow optical fiber can be increased. Therefore, the method for producing the hollow optical fiber can be used as an optical waveguide for an infrared laser, and can produce a hollow optical fiber that is flexibly and reversibly bent and that the metal layer is hardly peeled off.

  Here, the “main component” is a component having the highest content, for example, a component having a content of 50% by mass or more. The “arithmetic average roughness Ra” means an arithmetic average roughness measured according to JIS-B-0601 (2013).

[Details of the embodiment of the present invention]
Hereinafter, a hollow optical fiber according to an embodiment of the present invention, a method for manufacturing the hollow optical fiber, and an endoscope apparatus including the hollow optical fiber will be described in detail.

[Hollow optical fiber]
As shown in FIG. 1, the hollow optical fiber includes a tubular base layer 1, a metal layer 2 laminated on the inner surface of the base layer 1, and an inner surface of the metal layer 2, and infrared light. And a dielectric layer 3 capable of transmitting light. The hollow optical fiber can be used as an optical waveguide of an infrared laser, for example.

<Base material layer>
The main component of the base material layer 1 is a methylpentene polymer. Methyl pentene polymer has relatively high heat resistance and chemical resistance. For this reason, the said hollow optical fiber can perform the autoclave and ethanol sterilization performed, for example for 15 minutes at 120 degreeC by water vapor atmosphere.

  As a minimum of content of methyl pentene polymer in substrate layer 1, 60 mass% is preferred and 90 mass% is more preferred. If the content of the methylpentene polymer is less than the lower limit, the flexibility of the hollow optical fiber may be insufficient. On the other hand, the upper limit of the content of the methylpentene polymer is not particularly limited, and may be 100% by mass.

  As a minimum of the average outside diameter of base material layer 1, 0.3 mm is preferred and 0.6 mm is more preferred. On the other hand, the upper limit of the average outer diameter of the base material layer 1 is preferably 1.7 mm, more preferably 1.5 mm. There exists a possibility that the light quantity of the infrared laser which can pass the hollow part of the said hollow optical fiber is insufficient as the average outer diameter of the base material layer 1 is less than the said minimum. On the contrary, when the average outer diameter of the base material layer 1 exceeds the upper limit, it may be difficult to insert the endoscope layer with an endoscope apparatus or the like. Further, when the hollow optical fiber is bent, the cross section becomes an elliptical shape, which may increase transmission loss of the hollow optical fiber with respect to infrared light.

  As a minimum of average thickness of base material layer 1, 0.05 mm is preferred and 0.1 mm is more preferred. On the other hand, as an upper limit of the average thickness of the base material layer 1, 0.6 mm is preferable and 0.4 mm is preferable. There exists a possibility that the intensity | strength of the said hollow optical fiber may run short that the average thickness of the base material layer 1 is less than the said minimum. On the other hand, when the average thickness of the base material layer 1 exceeds the above upper limit, the amount of infrared laser light that can pass through the hollow portion of the hollow optical fiber may be insufficient.

  As a minimum of the Rockwell hardness of the base material layer 1, 40 is preferable and 50 is more preferable. On the other hand, as an upper limit of the Rockwell hardness of the base material layer 1, 100 is preferable and 90 is more preferable. When the Rockwell hardness of the base material layer 1 is less than the above lower limit, the straight advanceability when the hollow optical fiber is inserted is poor, and it may be difficult to insert into the living body from the endoscope apparatus. Conversely, if the Rockwell hardness of the base material layer 1 exceeds the upper limit, it may be difficult to control the bending of the hollow optical fiber. In addition, the Rockwell hardness of the base material layer 1 can be adjusted by adjusting the polymerization degree of a methylpentene polymer, for example. Here, “Rockwell hardness” is a value measured according to the standard of the R scale of ASTM-D785.

  The upper limit of the arithmetic average roughness Ra of the inner surface of the base material layer 1 is preferably 10 μm and more preferably 5 μm. When the arithmetic average roughness Ra of the inner surface of the base material layer 1 exceeds the above upper limit, the flatness of the inner surface of the metal layer 2 is insufficient, so that irregular reflection of the infrared laser increases, and the infrared light transmittance of the hollow optical fiber is increased. May decrease. On the other hand, the lower limit of the arithmetic average roughness Ra of the inner surface of the base material layer 1 is not particularly limited, and can be, for example, 0.02 μm. In addition, arithmetic mean roughness Ra of the inner surface of the base material layer 1 can be adjusted by, for example, extrusion conditions when the base material layer 1 is formed by an extrusion molding method.

  In addition, you may add various additives to the base material layer 1 as needed. Examples of such additives include metal powder for improving the strength and fibers such as fluororesin fibers. When adding an additive, as a minimum of content of an additive, 1 mass% is preferable and 5 mass% is more preferable. On the other hand, the upper limit of the content of the additive is preferably 20% by mass, and more preferably 10% by mass. There exists a possibility that the effect of an additive may not fully express that the said additive is less than the said minimum. On the contrary, when the additive exceeds the upper limit, the content of the methylpentene polymer is relatively reduced, and thus the flexibility of the hollow optical fiber and the adhesion with the metal layer 2 may be insufficient.

<Metal layer>
The main component of the metal layer 2 is silver. As the metal layer 2, an electroless silver plating layer is preferable. By making the metal layer 2 an electroless silver plating layer, the adhesiveness with the base material layer 1 can be improved and the production can be facilitated. Moreover, the inner surface of the metal layer 2 can be easily flattened according to the flatness of the inner surface of the base material layer 1.

  As a minimum of content of silver in metal layer 2, 90 mass% is preferred and 95 mass% is more preferred. If the silver content is less than the lower limit, the transmission loss of the hollow optical fiber with respect to infrared light may increase. On the other hand, the upper limit of the silver content is not particularly limited, and may be 100% by mass.

  The upper limit of the average thickness of the metal layer 2 is preferably 50 μm and more preferably 30 μm. When the average thickness of the metal layer 2 exceeds the upper limit, the metal layer 2 may be easily peeled off from the base material layer 1 due to a difference in internal stress or linear expansion coefficient between the base material layer 1 and the metal layer 2. On the other hand, the lower limit of the average thickness of the metal layer 2 is not particularly limited as long as the infrared laser can be reflected, and can be, for example, 0.1 μm.

  The upper limit of the arithmetic average roughness Ra of the inner surface of the metal layer 2 is preferably 10 μm and more preferably 5 μm. When the arithmetic average roughness Ra of the inner surface of the metal layer 2 exceeds the upper limit, the irregular reflection of the infrared laser increases, and the infrared light transmittance of the hollow optical fiber may decrease. On the other hand, the lower limit of the arithmetic average roughness Ra of the inner surface of the metal layer 2 is not particularly limited, and can be, for example, 0.02 μm. The arithmetic average roughness Ra of the inner surface of the metal layer 2 can be adjusted by controlling, for example, the arithmetic average roughness Ra of the inner surface of the base material layer 1.

<Dielectric layer>
The main component of the dielectric layer 3 is not particularly limited as long as it is a material that has little absorption and reflection with respect to the infrared light to be guided, that is, a material that is close to transparency. , Polyethylene terephthalate, polycarbonate and the like. Among these, COP or silver iodide is preferable. The dielectric loss of the dielectric layer 3 decreases as the refractive index approaches the square root of 2. Since COP has a refractive index of 1.45 or more and 1.55 or less, a hollow optical fiber having a small transmission loss can be formed. Moreover, since silver iodide has low reactivity with the base material layer 1, it is possible to suppress the deterioration with time of the hollow optical fiber.

  As a minimum of content of COP or silver iodide in dielectric material layer 3, 90 mass% is preferred and 95 mass% is more preferred. If the content of COP or silver iodide is less than the lower limit, transmission loss of the hollow optical fiber with respect to infrared light may increase. On the other hand, the upper limit of the content of COP or silver iodide is not particularly limited, and may be 100% by mass.

The average thickness of the dielectric layer 3 is such that there is interference between the light reflected by the metal layer 2 and the light reflected by the dielectric layer 3 in accordance with the wavelength of the infrared laser that transmits the hollow optical fiber. It is determined appropriately so as to occur. For example, when a CO ₂ laser (wavelength: 5.3 μm) is used, the average thickness of the dielectric layer 3 is set to about 0.5 μm. When an Er-YAG laser (wavelength: 2.94 μm) is used, the average thickness of the dielectric layer 3 is about 0.25 μm.

  The lower limit of the inner diameter of the dielectric layer 3 (the diameter of the hollow portion of the hollow optical fiber) is preferably 0.1 mm, and more preferably 0.3 mm. On the other hand, the upper limit of the inner diameter of the dielectric layer 3 is preferably 0.9 mm, and more preferably 0.8 mm. If the inner diameter of the dielectric layer 3 is less than the lower limit, the amount of infrared laser light that can pass through the hollow portion of the hollow optical fiber may be insufficient. On the contrary, if the inner diameter of the dielectric layer 3 exceeds the above upper limit, it is necessary to increase the average outer diameter of the base material layer 1 from the viewpoint of the strength of the hollow optical fiber, so that it is difficult to insert it in an endoscope apparatus or the like. There is a risk of becoming.

  The average outer diameter of the hollow optical fiber coincides with the average outer diameter of the base material layer 1. Specifically, the lower limit of the average outer diameter of the hollow optical fiber is preferably 0.3 mm, and more preferably 0.6 mm. On the other hand, the upper limit of the average outer diameter of the hollow optical fiber is preferably 1.7 mm, more preferably 1.5 mm. If the average outer diameter of the hollow optical fiber is less than the lower limit, the amount of infrared laser light that can pass through the hollow portion of the hollow optical fiber may be insufficient. Conversely, if the average outer diameter of the hollow optical fiber exceeds the upper limit, it may be difficult to insert the endoscope with an endoscope apparatus or the like.

  The lower limit of the average thickness of the hollow optical fiber is preferably 0.06 mm, and more preferably 0.1 mm. On the other hand, the upper limit of the average thickness of the hollow optical fiber is preferably 0.6 mm, and more preferably 0.4 mm. If the average thickness of the hollow optical fiber is less than the lower limit, the strength of the hollow optical fiber may be insufficient. Conversely, if the average thickness of the hollow optical fiber exceeds the upper limit, the amount of infrared laser light that can pass through the hollow portion of the hollow optical fiber may be insufficient. The “average thickness of the hollow optical fiber” refers to the average thickness of the base layer 1, the metal layer 2, and the dielectric layer 3.

  The upper limit of the bending radius at which the hollow optical fiber breaks is preferably 8 mm, more preferably 5 mm, and even more preferably 1 mm. If the bending radius at which the fracture occurs exceeds the upper limit, the range in which the hollow optical fiber is bent is restricted, and it may be difficult to insert the endoscope into the living body. Here, the “bending radius at which the hollow optical fiber breaks” refers to a bending radius at which 5% of the hollow optical fibers are broken when the plurality of hollow optical fibers are bent until the breaking occurs.

[Method for producing hollow optical fiber]
The method for manufacturing the hollow optical fiber includes a base material layer forming step, a base material layer inner surface treatment step, a metal layer forming step, and a dielectric layer forming step.

(Base material layer forming step)
In the base material layer forming step, the tubular base material layer 1 mainly composed of methylpentene polymer is formed by an extrusion molding method.

  In this step, the base material layer 1 is formed by extruding the base material layer forming material using a known melt extrusion molding machine. As the base material layer forming material, a material in which various additives are added to the methylpentene polymer as required can be used.

  Although the die temperature in a base material layer formation process is not specifically limited, For example, it can be 250 to 340 degreeC higher than melting | fusing point of the methylpentene polymer which is a forming material.

  As a minimum of extrusion line speed in an extrusion process, 2 m / min is preferred and 3.5 m / min is more preferred. On the other hand, the upper limit of the extrusion linear velocity is preferably 30 m / min, and more preferably 25 m / min. There exists a possibility that the productivity of the said hollow optical fiber may become inadequate that the said extrusion linear velocity is less than the said minimum. On the contrary, if the extrusion linear velocity exceeds the upper limit, the flatness of the inner surface of the base material layer 1 is insufficient, so that the irregular reflection of the infrared laser increases and the infrared light transmittance of the hollow optical fiber may decrease. is there.

(Base layer inner surface treatment process)
In the substrate layer inner surface treatment step, the inner surface of the substrate layer 1 is plasma treated. By performing plasma treatment on the surface of the base material layer 1, the CH group or the like of the methylpentene polymer is activated, so that the adhesion between the base material layer 1 and the metal layer 2 can be improved.

  Examples of the plasma used for the plasma treatment include oxygen, nitrogen, air, water vapor, and the like. Of these, oxygen plasma is preferable. Oxygen plasma can improve the adhesion between the base material layer 1 and the metal layer 2 by improving the hydrophilicity of the inner surface of the base material layer 1.

(Metal layer forming process)
In the metal layer forming step, the metal layer 2 is formed on the inner surface of the base material layer 1 by electroless silver plating. Electroless silver plating is performed using a silver mirror reaction. Specifically, by injecting a silver nitrate aqueous solution and a reducing agent such as an aldehyde into the base material layer 1, the silver is reduced and deposited on the surface of the base material layer 1. The solution after the silver mirror reaction is discharged. In this way, the metal layer 2 is formed on the inner surface of the base material layer 1.

(Dielectric layer forming process)
In the dielectric layer forming step, the dielectric layer 3 capable of transmitting infrared light is formed on the inner surface of the metal layer 2.

  As the main component of the dielectric layer 3, for example, cyclic olefin polymer (COP) or silver iodide can be suitably used. When the main component of the dielectric layer 3 is COP, the COP diluted with mesitylene or cyclohexane as a solvent is introduced into the inner surface of the metal layer 2 and then dried while heating to form the dielectric layer 3. be able to. As said heating temperature, it can be 180 degreeC or more and 220 degrees C or less, for example. Moreover, as said heat drying time, it can be set as 50 minutes or more and 70 minutes or less.

  Further, when the main component of the dielectric layer 3 is silver iodide, the dielectric layer 3 can be formed by iodideing silver, which is the main component of the metal layer 2.

[Endoscope device]
As shown in FIG. 2, the endoscope apparatus includes a tubular insertion portion 10 that is inserted into a subject, and an operation portion 20 that is disposed on the proximal end side of the insertion portion 10. Further, the endoscope apparatus includes a laser light guide module 30 that can be inserted into the insertion portion 10 and a light source 31 configured to emit an infrared laser in the laser light guide module 30. Here, the “proximal end side” of the insertion portion 10 refers to the rear end portion when the insertion portion 10 is inserted into the subject.

<Insertion section>
The insertion unit 10 is cylindrical and flexible, and is configured such that the distal end side (the front end when the insertion unit 10 is inserted into the subject) is bent by an operation from the operation unit 20. . Thereby, the front-end | tip part of the insertion part 10 can be orient | assigned to a desired direction. The length of the insertion portion 10 is determined so as to reach a desired site from the oral cavity or the like of the subject, and can be, for example, 1 m or more and 3 m or less. The diameter of the insertion portion 10 can be 5 mm or more and 10 mm or less at the distal end portion.

  The insertion portion 10 includes a forceps channel 11 having an insertion port for inserting a treatment tool in the vicinity of the proximal end side. The insertion section 10 can insert the laser light guide module 30 into the forceps channel 11 from the insertion port and push out one end of the laser light guide module 30 from the distal end side of the insertion section 10. It is configured.

  The laser light guide module 30 includes the hollow optical fiber shown in FIG. 1, a lens disposed on the distal end side of the hollow optical fiber, and a connector for connecting the lens and the light source 31. The lens is not particularly limited as long as it can be connected to an optical fiber and can emit infrared light. For example, a known convex lens can be used.

  The length of the laser light guide module 30 is substantially the same as the length of the hollow optical fiber and depends on the length of the insertion portion 10, but can be, for example, 2 m or more and 5 m or less. Since the endoscope apparatus can orient the distal end of the insertion portion 10 in a desired direction as described above, the distal end of the laser light guide module 30 can be treated at a desired site in the subject. The part can be located.

The endoscope apparatus includes a light source 31 configured to emit an infrared laser in the laser light guide module 30. Since the infrared laser beam that has passed through the hollow optical fiber by the light source 31 can be emitted from the distal end portion of the laser light guide module 30 through the lens, it is possible to treat a desired site in the subject. Infrared laser used for the light source 31 is not particularly limited, for example, CO ₂ laser or Er-YAG laser.

  The insertion unit 10 may include a photographing optical device and an illumination optical device on the distal end side. As described above, the insertion unit 10 includes the photographing optical device and the illumination optical device on the distal end side, so that the treatment can be performed while viewing the state of the portion to be treated by the infrared laser from the distal end side of the insertion portion 10. These devices are configured to be controlled from the operation unit 20.

<Operation unit>
The shape and size of the operation unit 20 are not particularly limited, but from the viewpoint of operability, for example, one side can be a cube having a size of 5 cm to 10 cm. The operation unit 20 includes an angle adjustment knob 21 that bends the distal end side of the insertion unit 10, and a switch 22 that controls various functions such as a photographing optical device and an illumination optical device attached to the insertion unit 10. In addition, the operation unit 20 includes a cable 23 that outputs an image captured by, for example, an imaging optical device to an external display device or the like as necessary.

  The surgeon inserts the insertion unit 10 of the endoscope apparatus from the oral cavity of the subject and then controls the insertion unit 10 using the operation unit 20, thereby specifying and treating the inspection target region and inserting the endoscope unit 10. The advancing / retreating operation of the unit 10 can be performed smoothly.

〔advantage〕
In the hollow optical fiber, since the main component of the metal layer 2 is silver, the metal layer 2 having high flatness, that is, less diffuse reflection can be formed on the inner surface of the base material layer 1. For this reason, the hollow optical fiber causes light interference such that the light reflected by the metal layer 2 and the light reflected by the dielectric layer 3 strengthen each other, and the reflectance of the infrared laser can be increased. Moreover, since the main component of the base material layer 1 is a methylpentene polymer, the hollow optical fiber can be bent flexibly and reversibly. Furthermore, since the said hollow optical fiber has comparatively high adhesiveness of the base material layer 1 and the metal layer 2, it can make it difficult to peel off the metal layer 2 laminated | stacked on the inner surface of the base material layer 1. FIG. Therefore, the hollow optical fiber can be used as an optical waveguide of an infrared laser, bent flexibly and reversibly, and the metal layer 2 is hardly peeled off.

  Moreover, the manufacturing method of the said hollow optical fiber can be used as an optical waveguide of an infrared laser, can manufacture the hollow optical fiber which is bent flexibly and reversibly and the metal layer 2 is hard to peel off.

  Further, the endoscope apparatus can be inserted with a laser light guide module 30 including the hollow optical fiber. The hollow optical fiber is bent flexibly and reversibly, and the metal layer 2 is hardly peeled off. Therefore, the endoscope apparatus can suitably use an infrared laser in the medical field by using the hollow optical fiber as an infrared laser waveguide.

[Other Embodiments]
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is not limited to the configuration of the embodiment described above, but is defined by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims. The

  For example, the hollow optical fiber may be laminated with a resin layer formed of a fluororesin or the like as a protective layer on the outer surface of the base material layer.

  In the said embodiment, although the method to activate the inner surface of a base material layer by plasma processing was demonstrated as a manufacturing method of the said hollow optical fiber, you may activate the inner surface of a base material layer by another method. Other methods include, for example, a method of spraying ethane gas mixed with ozone to increase the reactivity onto the inner surface of the base material layer, a method of pouring an alkaline solution inside the base material layer, and the like.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples.

[No. 1]
As a base layer of the hollow optical fiber, a tubular base layer mainly composed of methylpentene polymer was formed by extrusion molding. Extrusion molding was performed under conditions of a temperature of 300 ° C. and a linear speed of 3.5 m / min. The base layer had an average outer diameter of 1.3 mm, an average thickness of 0.3 mm, and a length of 1 m.

  After the inner surface of the base material layer was subjected to oxygen plasma treatment, a metal layer was formed by electroless silver plating. The average thickness of the metal layer was 35 μm.

  Furthermore, after injecting COP using mesitylene as a solvent into the inner surface of the metal layer, the dielectric layer was formed by drying at 60 ° C. for 60 minutes. The average thickness of the dielectric layer was 0.5 μm. In this way, no. 1 hollow optical fiber was obtained.

[No. 2]
As a base layer of the hollow optical fiber, a borosilicate quartz glass tube was stretched by heating at 1300 ° C. to form a tubular base layer. The base layer had an average outer diameter of 0.85 mm, an average thickness of 0.075 mm, and a length of 1 m.

  No. except that the inner surface of the base material layer was not plasma-treated. In the same manner as in Example 1, a metal layer and a dielectric layer were formed. In this way, no. Two hollow optical fibers were obtained.

(Evaluation)
No. 1 and no. Two hollow optical fibers of 2 were produced and subjected to a bending test to determine the bending radius at which breakage occurred.

(result)
No. No hollow fiber optical fiber 1 was broken even when the bending radius was 5 mm. In contrast, no. As for the hollow optical fiber of No. 2, some were broken at a bending radius of 9 mm, and all were broken at a bending radius of 8 mm.

  Based on the above results, In the hollow optical fiber No. 1, the main component of the base material layer is methylpentene polymer, and thus the hollow optical fiber is considered to have excellent flexibility. In contrast, no. The hollow optical fiber 2 is considered to be inferior in flexibility because the main component of the base material layer is quartz.

  The hollow optical fiber of the present invention can be used as an optical waveguide of an infrared laser, is flexibly and reversibly bent, and further, the metal layer is hardly peeled off. Therefore, the hollow optical fiber of the present invention is suitably used as a hollow optical fiber for an endoscope apparatus. In addition, the method for producing a hollow optical fiber of the present invention can make a hollow optical fiber that can be bent flexibly and reversibly while making it difficult to peel off the metal layer.

DESCRIPTION OF SYMBOLS 1 Base material layer 2 Metal layer 3 Dielectric layer 10 Insertion part 11 Forceps channel 20 Operation part 21 Angle adjustment knob 22 Switch 23 Cable 30 Laser light guide module 31 Light source

Claims (5)

A hollow optical fiber comprising a tubular substrate layer, a metal layer laminated on the inner surface of the substrate layer, and a dielectric layer laminated on the inner surface of the metal layer and capable of transmitting infrared light. ,
The main component of the base material layer is methylpentene polymer,
A hollow optical fiber in which the main component of the metal layer is silver.   The hollow optical fiber according to claim 1, wherein the main component of the dielectric layer is a cyclic olefin polymer or silver iodide.   The hollow optical fiber according to claim 1 or 2, wherein an arithmetic average roughness Ra of the inner surface of the metal layer is 10 µm or less. An endoscope apparatus comprising a tubular insertion portion to be inserted into a subject and an operation portion disposed on a proximal end side of the insertion portion,
A laser light guide module that can be inserted into the insertion portion;
The laser light guide module includes a light source configured to emit an infrared laser,
An endoscope apparatus in which the laser light guide module includes the hollow optical fiber according to claim 1, claim 2, or claim 3. A step of forming a tube-shaped substrate layer mainly composed of methylpentene polymer by an extrusion method;
Plasma treatment of the inner surface of the base material layer;
Forming a metal layer on the inner surface of the base material layer by electroless silver plating;
Forming a dielectric layer capable of transmitting infrared light on the inner surface of the metal layer.

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