JP2009204683A - Hollow fiber and manufacturing method of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hollow fiber equipped with a transparent thin film having a little roughness on the surface and a nearly uniform film thickness in the longitudinal direction of the hollow fiber, and also to provide the manufacturing method of the same. <P>SOLUTION: The hollow fiber 1 includes a hollow tube having a hollow region 14 in which light propagates, a first metallic thin film formed on the inner wall of the hollow tube and has chemical stability, and the transparent thin film for which a second thin metallic film is chemically changed and formed transparent against light wavelength, wherein the second thin metallic film is formed of metallic nano particles on a surface opposite to the surface where the first thin metallic film is brought into contact with the inner wall. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hollow fiber and a method for manufacturing a hollow fiber. In particular, the present invention relates to a hollow fiber including a reflective layer having a substantially uniform film thickness along the longitudinal direction of the hollow fiber and a method for manufacturing the hollow fiber.

  As a conventional hollow fiber, there is a hollow fiber including a glass capillary having a hollow structure, a silver thin film coated on the inner wall of the glass capillary, and a silver iodide thin film formed on the surface of the silver thin film (for example, non-patent literature) 1).

  A hollow fiber described in Non-Patent Document 1 is a glass capillary as a base material of a hollow optical fiber, in which a silver solution in which silver nitrate is dissolved and a reducing solution containing glucose as a reducing agent are simultaneously sucked and mixed by a vacuum pump. By flowing in, silver particles are deposited on the inner wall of the glass capillary to form a silver thin film (silver mirror plating method). Subsequently, a hollow fiber is obtained by injecting a solution in which iodine is dissolved into a glass capillary to chemically change a part of the silver thin film to silver iodide.

  Since the hollow fiber described in Non-Patent Document 1 has a hollow structure, a pulse laser beam having a high peak power, or an infrared wavelength of 2 μm or more where a quartz material cannot be used as a transmission medium due to an infrared absorption loss It can be used as a band optical transmission path, and since the silver thin film and the transparent layer are provided on the inner wall of the capillary, the transmission loss of light in the infrared region can be reduced.

J. Harrington, “A Review of IR Transmitting, Hollow Waveguides”, Fiber and Integrated Optics, Vol. 19, pp. 211-227 (2000)

  However, since the hollow fiber according to Non-Patent Document 1 forms a silver thin film by a silver mirror plating method, the silver thin film has a film thickness distribution in the longitudinal direction of the hollow fiber. In addition, since a silver iodide thin film is formed by performing iodine treatment on a part of the silver thin film, the silver thin film formed on the inner wall of the glass capillary needs to be formed as a thick film of about several μm. Therefore, the surface of the silver iodide thin film of the hollow fiber according to Non-Patent Document 1 cannot take over the mirror surface of the inner wall of the glass capillary. Furthermore, the film thickness of the silver iodide thin film is controlled by the time between the silver thin film and the solution in which iodine is dissolved, and the reaction rate varies depending on the iodine concentration in the solution in which iodine is dissolved and the liquid temperature of the solution. Therefore, it is difficult to obtain a silver iodide thin film having a uniform thickness over the longitudinal direction of the hollow fiber.

  Accordingly, an object of the present invention is to provide a hollow fiber having a transparent thin film having a small surface roughness on the surface of the transparent thin film and having a substantially uniform film thickness in the longitudinal direction of the hollow fiber, and a method for producing the hollow fiber. .

  To achieve the above object, the present invention provides a hollow tube having a hollow region through which light propagates, a first metal thin film formed on the inner wall of the hollow tube and having chemical stability, and a first metal Provided is a hollow fiber comprising a transparent thin film formed transparently with respect to the wavelength of light by chemically changing a second metal thin film formed of metal nanoparticles on the surface opposite to the surface in contact with the inner wall of the thin film Is done.

  In the hollow fiber, the metal nanoparticles may be Ag nanoparticles, and the transparent thin film may contain silver iodide formed by subjecting a silver thin film formed from the Ag nanoparticles to iodine treatment. Alternatively, the metal nanoparticles may be Cu nanoparticles, and the transparent thin film may include copper oxide formed by oxidizing a copper thin film formed from Cu nanoparticles.

  In order to achieve the above object, the present invention injects a first nanoparticle solution in which a first metal nanoparticle is dispersed in a solvent into a hollow tube having a hollow region through which light propagates. A first nanoparticle solution attaching step for attaching the first nanoparticle solution to the inner wall of the hollow tube, and a first metal thin film having chemical stability from the first nanoparticle solution attached to the inner wall. A first metal thin film forming step formed on the inner wall; and a second nanoparticle solution in which the second metal nanoparticles are dispersed in a solvent is injected into the hollow tube to form a surface of the first metal thin film First, the second metal thin film is attached to the first metal thin film from the second nano particle solution attachment step of attaching the second nano particle solution and the second nano particle solution attached to the surface of the first metal thin film. The second metal thin film forming step formed on the surface of the metal, and the hollow tube chemically reacts with the second metal thin film. A method for producing a hollow fiber, comprising: a transparent thin film forming substance that forms a transparent thin film on a first metal thin film from a second nanoparticle solution by flowing a transparent thin film forming substance that forms a transparent thin film transparent to light. Is provided.

  In the above hollow fiber manufacturing method, the second nanoparticle solution adhering step uses Ag nanoparticles as the second metal nanoparticles, and the second metal thin film forming step starts from the Ag nanoparticles with the second metal. An Ag thin film is formed as a thin film, and in the transparent thin film forming step, an iodine solution containing iodine is used as a transparent thin film forming substance, and the iodine solution and the Ag thin film are brought into contact with each other for a certain period of time. A thin film may be formed.

  In the hollow fiber manufacturing method, the second nanoparticle solution adhering step uses Cu nanoparticles as the second metal nanoparticles, and the second metal thin film forming step starts from the Cu nanoparticles with the second metal. A Cu thin film is formed as a thin film, and the transparent thin film forming step uses oxygen as a transparent thin film forming material, and contacts the oxygen and Cu thin film for a certain period of time, thereby forming a copper oxide thin film as a transparent thin film from the Cu thin film. Good.

  In order to achieve the above object, the present invention injects a first nanoparticle solution in which a first metal nanoparticle is dispersed in a solvent into a hollow tube having a hollow region through which light propagates. A first nanoparticle solution attaching step for attaching the first nanoparticle solution to the inner wall of the hollow tube, and a first metal thin film having chemical stability from the first nanoparticle solution attached to the inner wall. A first metal thin film forming step formed on the inner wall; and a second nanoparticle solution in which the second metal nanoparticles are dispersed in a solvent is injected into the hollow tube to form a surface of the first metal thin film In addition, a second nanoparticle solution attaching step for attaching the second nanoparticle solution and a gas containing oxygen in the hollow tube are circulated to form a transparent thin film transparent to light from the second nanoparticle solution. A method for producing a hollow fiber comprising a transparent thin film forming step formed on a metal thin film It is.

According to the hollow fiber and the hollow fiber manufacturing method according to the present invention, the surface of the transparent thin film has a small surface roughness, and the hollow fiber includes a transparent thin film having a substantially uniform film thickness in the longitudinal direction of the hollow fiber. A manufacturing method can be provided.
Can provide.

[First Embodiment]
Fig.1 (a) shows an example of the partial cross section of the hollow fiber which concerns on the 1st Embodiment of this invention, (b) shows an example of the cross section of the hollow fiber in an AA line.

(Configuration of hollow fiber 1)
As shown in FIGS. 1A and 1B, a hollow fiber 1 according to the first embodiment of the present invention includes a capillary 10 having a predetermined length as a hollow tube and a capillary 10 having a mirror surface state. The gold (Au) thin film 12 is provided as a metal thin film having a function as a reflective layer that reflects light propagating through the hollow region 14, and is opposite to the surface of the gold thin film 12 in contact with the inner wall of the capillary 10. A silver iodide thin film 13 as a transparent thin film formed on the side surface by a chemical reaction and a protective layer 15 covering the outer surface of the capillary 10 are provided.

  A capillary 10 as a base material of the hollow fiber 1 has a cylindrical shape and is formed to include a hollow region 14 in which light of a predetermined wavelength propagates. The hollow region 14 is a region filled with a gas such as air. The capillary 10 is formed of a material having an inner wall that is sufficiently smooth with respect to the wavelength of light propagating through the hollow region 14, has excellent optical characteristics, and has heat resistance. For example, a quartz glass capillary made of quartz glass as an inorganic material, a polymer resin tube made of a predetermined polymer as a polymer material, or a stainless steel pipe made of stainless steel as a metal material can be used as the capillary 10. .

  Specifically, in the present embodiment, a small-diameter capillary made of quartz glass having an inner diameter d1 of 500 μm and an outer diameter d2 of 650 μm and excellent in flexibility can be used as the capillary 10. In addition, when it is required to use the capillary 10 that has excellent flexibility and is not easily damaged, a polymer resin tube can be used as the capillary 10. Further, when it is required to use a capillary 10 having a high impact resistance and having a characteristic that is not easily damaged and having an excellent thermal conductivity required for transmission of a high-power laser beam, the capillary 10 is made of stainless steel. Steel pipes can be used.

  The metal thin film provided on the inner wall of the capillary 10 is formed of a material having good chemical stability and property stability that does not substantially cause corrosion and / or discoloration. Specifically, the metal thin film according to the present embodiment is formed on the inner wall of the capillary 10 by sintering the gold nanoparticles using the gold (Au) nanoparticles as the first metal nanoparticles as a raw material. This is a gold thin film 12 as a first metal thin film. For example, the gold thin film 12 is formed with a film thickness d3 that is sufficiently thicker than the optical skin depth and is several tens of nm or less by sintering gold nanoparticles having a predetermined average particle diameter. Is done. The optical skin depth is defined by a film thickness d at which light energy is attenuated to exp (−1), and is defined by an expression represented by d = λ / (4πk). Note that λ is the wavelength of light propagating through the hollow region 14, and k is the extinction coefficient of the material.

  In addition, if the optical property (for example, the characteristic which shows high reflectance) excellent in the wavelength of the light which propagates the hollow area | region 14 is shown, and it is excellent in chemical stability, the metal nanoparticle which forms a metal thin film will be shown. The particles are not limited to Au nanoparticles. In addition, as the gold nanoparticles before sintering, those having an average particle diameter of 10 nm or less are used. For example, the gold thin film 12 can be formed using Au nanoparticles having an average particle diameter of 3 nm to 5 nm.

  The silver iodide thin film 13 as a transparent thin film formed transparently with respect to a predetermined wavelength of light is formed using silver (Ag) nanoparticles as second metal nanoparticles different from Au nanoparticles as a raw material. A silver (Ag) thin film as the second metal thin film is formed by chemical change. Specifically, in the silver iodide thin film 13, the silver thin film is chemically changed to the silver iodide thin film 13 by subjecting the silver thin film formed on the surface 12a of the gold thin film 12 to a predetermined film thickness with iodine treatment. Formed. The silver iodide thin film 13 functions as a transparent layer (dielectric layer) that is transparent to light in the wavelength band from the visible light region to the infrared light region.

  Here, the light propagating through the hollow fiber 1 is repeatedly reflected at the boundary between the hollow region 14 and the silver iodide thin film 13 as a transparent thin film, and at the boundary between the silver iodide thin film 13 and the gold thin film 12. 14 propagates along the longitudinal direction of the hollow fiber 1. The light reflected at the boundary between the hollow region 14 and the silver iodide thin film 13 and the light transmitted through the silver iodide thin film 13 and reflected at the boundary between the silver iodide thin film 13 and the gold thin film 12 are in phase. Sometimes the reflectivity of the hollow fiber inner wall is maximized. Therefore, by providing the silver iodide thin film 13 having a uniform film thickness precisely controlled according to the wavelength of light to be transmitted on the inner wall of the gold thin film 12, light transmission loss can be reduced. In the present embodiment, the silver iodide thin film 13 is formed with a film thickness set according to the wavelength of light transmitted through the hollow region 14 within a film thickness range of several tens of nm or less. That is, the silver thin film and the silver iodide thin film 13 are formed with a film thickness of several tens of nm or less as an example.

  The protective layer 15 is formed so as to cover the outer periphery of the capillary 10. As an example, the protective layer 15 is formed of polyimide as a polymer resin material having excellent thermal characteristics, chemical characteristics, and mechanical characteristics.

(Method for producing hollow fiber 1)
2A to 2F show an example of the manufacturing process of the hollow fiber according to the first embodiment of the present invention.

  First, as shown in FIG. 2A (a), a syringe 20 having dissolution resistance to an organic solvent is attached to the other end 18 as the upper end of the capillary 10 made of quartz glass. The syringe 20 is composed of a columnar piston 20a and a cylindrical cylinder 20b, and constitutes a syringe pump that drives the piston 20a with high accuracy. Then, a predetermined volume of the gold nanoparticle solution 40 is accommodated in the cylinder 20b.

  Here, the gold nanoparticle solution 40 is a solution prepared by dispersing a predetermined amount of gold nanoparticles in an organic solvent as a predetermined solvent. In the present embodiment, toluene can be used as an organic solvent having excellent volatility for dispersing gold nanoparticles. The gold nanoparticle solution 40 can also be prepared by dispersing gold nanoparticles in an organic solvent such as hexane or tetradecane or an organic solvent such as terpineol.

  Next, as shown in FIGS. 2A and 2C, the piston 20a of the syringe 20 is driven at a constant speed in the pushing direction (the direction from the other end 18 of the capillary 10 toward the tip 16 of the capillary 10). . The gold nanoparticle solution 40 is discharged from the cylinder 20b at a constant speed in accordance with the pushing drive of the piston 20a. Then, the discharged gold nanoparticle solution 40 is injected into the capillary 10.

  The gold nanoparticle solution 40 injected into the capillary 10 adheres to the inner wall of the capillary 10 as it moves from the other end 18 of the capillary 10 toward the tip 16. Then, the gold nanoparticle solution 40 that is not attached to the inner wall of the capillary 10, that is, the extra gold nanoparticle solution 40, is discharged from the tip 16 of the capillary 10 to the outside of the capillary 10 and is shown in FIG. As shown, it is contained in a waste liquid container 45.

  Subsequently, as shown in FIG. 2B (d), the capillary 10 with the gold nanoparticle solution 40 attached to the inner wall is placed in the electric furnace 50. Then, high temperature heat treatment is applied to the capillary 10 while introducing nitrogen gas 60 as an inert gas from the other end 18 of the capillary 10 to the tip end 16 side. As a result, the gold nanoparticle solution 40 is sintered, and as shown in FIG. 2B (e) as a cross-sectional view taken along line BB in FIG. Is formed on the inner wall of the capillary 10. In this case, since the thickness of the gold thin film 12 is thin enough to take over the shape of the inner wall surface of the capillary 10, the surface roughness of the surface 12 a of the gold thin film 12 is that of the capillary 10. The surface roughness is the same as the surface roughness of the inner wall surface.

  In this embodiment, the nitrogen gas 60 is used as the gas introduced into the capillary 10, but argon gas or helium gas as an inert gas other than the nitrogen gas 60 may be used. In addition, air can be introduced into the capillary 10 to heat-treat the capillary 10 with the gold nanoparticle solution 40 attached to the inner wall.

  In addition, the heat treatment can obtain sufficient optical properties and mechanical strength, and can form a gold thin film 12 having a density high enough to allow the gold thin film 12 and the capillary 10 to adhere to each other with sufficient adhesion. This is done. Further, the heat treatment is performed at a temperature below a temperature at which the gold nanoparticles contained in the gold nanoparticle solution 40 are aggregated and a gold thin film having particles having a particle diameter of a predetermined value or more is not formed. In the present embodiment, as an example, heat treatment at a temperature in the range of 200 ° C. to 300 ° C. is performed on the capillary 10 while flowing the nitrogen gas 60 into the capillary 10. Even when the protective layer 15 is provided on the outer periphery of the capillary 10, when the protective layer 15 is formed of polyimide, the polyimide is substantially in the temperature range of 200 ° C. to 300 ° C. of the heat treatment. It does not change due to thermal decomposition.

  Next, as shown in (f) to (h) of FIG. 2C and (i) of FIG. 2D, in the same manner as the formation process of the gold thin film 12 shown in (a) to (c) of FIG. A thin film 17 is formed. That is, first, as shown in FIG. 2C (f), the syringe 20 is attached to the other end 18 of the capillary 10 in which the gold thin film 12 is formed on the inner wall. And the silver nanoparticle solution 42 as a 2nd metal nanoparticle solution of predetermined capacity | capacitance is accommodated in the cylinder 20b. In the present embodiment, the second metal nanoparticle solution is prepared by dispersing silver (Ag) nanoparticles as second metal nanoparticles in a predetermined organic solvent. Here, in the present embodiment, toluene can be used as an organic solvent having excellent volatility for dispersing silver nanoparticles. The silver nanoparticle solution 42 can also be prepared by dispersing silver nanoparticles in an organic solvent such as hexane or tetradecane.

  Next, as shown in (g) and (h) of FIG. 2C, the piston 20a of the syringe 20 is driven in the pushing direction at a constant speed. The silver nanoparticle solution 42 is discharged from the cylinder 20b at a constant speed in accordance with the pushing drive of the piston 20a. Then, the discharged silver nanoparticle solution 42 is injected into the capillary 10. The silver nanoparticle solution 42 injected into the capillary 10 adheres to the surface of the gold thin film 12 formed on the inner wall of the capillary 10 as it moves from the other end 18 of the capillary 10 toward the tip 16. Then, the silver nanoparticle solution 42 not attached to the surface of the gold thin film 12, that is, the excess silver nanoparticle solution 42 is discharged from the tip portion 16 of the capillary 10 to the outside of the capillary 10, and (h) in FIG. As shown in FIG.

  Subsequently, as shown in (i) of FIG. 2D, the capillary 10 with the silver nanoparticle solution 42 attached to the surface of the gold thin film 12 is installed in the electric furnace 50. In addition, since the thickness of the silver nanoparticle solution 42 adhering to the surface of the gold thin film 12 is thin enough to be formed by taking over the shape of the surface of the gold thin film 12, the surface of the silver nanoparticle solution 42 ( The surface roughness of the surface opposite to the surface where the silver nanoparticle solution 42 and the gold thin film 12 are in contact with each other is as small as the surface roughness of the gold thin film 12.

  Then, high temperature heat treatment is applied to the capillary 10 while introducing the nitrogen gas 60 from the other end 18 of the capillary 10 to the tip end 16 side. As a result, the silver nanoparticle solution 42 is sintered, and a silver thin film 17 having a thickness of several tens of nm or less is formed on the surface of the gold thin film 12 as shown in FIG. 2D (j). In this case, since the film thickness of the silver thin film 17 is thin enough to take over the shape of the surface of the gold thin film 12, the surface roughness of the silver thin film 17 is the surface roughness of the surface of the gold thin film 12. And the same level of roughness.

  In the present embodiment, the nitrogen gas 60 is used as the gas introduced into the capillary 10, but an inert gas such as argon gas or helium gas other than the nitrogen gas 60 may be used. In addition, air can be introduced into the capillary 10 to heat-treat the capillary 10 with the silver nanoparticle solution 42 attached to the inner wall.

  Subsequently, as shown in (k) of FIG. 2E, the syringe 20 is attached again to the other end 18 of the capillary 10 on which the silver thin film 17 is formed. And the iodine solution 44 as a transparent thin film forming substance of predetermined capacity | capacitance is accommodated in the cylinder 20b. The iodine solution 44 according to the present embodiment is a solution prepared by dissolving iodine at a concentration of about 1% in cyclohexane as an organic solvent.

  Next, as shown in (l) and (m) of FIG. 2E, the piston 20a of the syringe 20 is driven in the pushing direction at a constant speed. The iodine solution 44 is discharged from the cylinder 20b in accordance with the pushing drive of the piston 20a. Then, the discharged iodine solution 44 is injected into the capillary 10. The iodine solution 44 injected into the capillary 10 comes into contact with the silver thin film 17 for several seconds to several minutes and is discharged from the tip end portion 16 of the capillary 10 to the outside of the capillary 10. Then, the discharged iodine solution 44 is accommodated in a waste liquid container 45 as shown in FIG.

  In the present embodiment, the iodine solution 44 injected into the capillary 10 chemically reacts with the silver thin film 17. That is, the silver which comprises the silver thin film 17, and the iodine in the iodine solution 44 combine. By this combination, all of the silver thin film 17 becomes the silver iodide thin film 13. Here, since the silver thin film 17 is formed on the surface of the gold thin film 12, the chemical reaction between silver and iodine stops at the boundary between the silver thin film 17 and the gold thin film 12. In other words, in the present embodiment, the gold thin film 12 has a function as a reaction stop layer that stops the chemical reaction between silver in the silver thin film 17 and iodine in the iodine solution 44. Therefore, in the present embodiment, if the contact time between the iodine solution 44 injected into the capillary 10 and the silver thin film 17 is longer than a predetermined time, the contact time between the iodine solution 44 and the silver thin film 17 is strictly set. There is no need to control.

  Further, the surface roughness of the silver thin film 17 shows the same degree of roughness as the surface roughness of the gold thin film 12, and the surface roughness of the silver thin film 17 is compared with the wavelength of light propagating through the hollow region 14. Small enough. The surface roughness of the surface 13a of the silver iodide thin film 13 formed by chemically changing the silver thin film 17 (the surface opposite to the surface in contact with the gold thin film 12 and in contact with the hollow region 14) is also the surface roughness. Similar to the silver thin film 17, it is sufficiently smaller than the wavelength of light propagating through the hollow region 14.

  Subsequently, as shown in (n) of FIG. 2F, an organic solvent such as ethanol, which is a cleaning organic solvent and has high volatility, is applied from the other end 18 side of the capillary 10 toward the tip end 16 side. 10 is injected. Then, after the inside of the capillary 10 is washed, the inside of the capillary 10 is dried, and then a protective layer 15 is provided on the outer periphery of the capillary 10, so that this embodiment as shown in FIG. Such a hollow fiber 1 is obtained.

  In this embodiment, the syringe pump is used for transporting the solution. However, a peristaltic pump can be used instead of the syringe pump. The peristaltic pump transports the solution by contracting the elastic tube into a wave shape. According to the peristaltic pump, the solution transport speed can be controlled with high accuracy, similar to the syringe pump. Therefore, a predetermined thin film can be formed with a substantially uniform film thickness on the inner wall of the capillary 10 and the surface of the gold thin film 12 by the peristaltic pump as well as the syringe pump.

(Effects of the first embodiment)
In the hollow fiber 1 according to the first embodiment of the present invention, a silver thin film 17 having a substantially uniform film thickness is formed on the chemically stable gold thin film 12 along the longitudinal direction of the hollow fiber 1. All of the formed silver thin film 17 can be chemically changed to the silver iodide thin film 13. The hollow fiber 1 according to the present embodiment is a transparent thin film having a substantially uniform film thickness along the longitudinal direction of the hollow fiber 1 and a surface roughness as small as the surface roughness of the inner wall of the capillary 10. As a silver iodide thin film 13 can be formed.

  Therefore, in the hollow fiber 1 according to the present embodiment, the film thicknesses of the gold thin film 12 and the silver iodide thin film 13 are substantially uniform along the longitudinal direction of the hollow fiber 1, which is almost the same as the surface roughness of the inner wall of the capillary 10. Therefore, it is possible to transmit infrared light including far-infrared light and to light having a wavelength shorter than that of infrared light (for example, visible light). For example, the light in the optical region can be superimposed and transmitted as guide light.

  In addition, since the hollow fiber 1 according to the present embodiment includes the silver iodide thin film 13 having a surface that approximates a mirror surface, even when the laser beam in the infrared wavelength band is transmitted at a high output, the breakdown threshold value is obtained. Can be improved. That is, the hollow fiber 1 according to the present embodiment can transmit light in the wavelength band from visible light to infrared light, and is very spatially or temporally like high-power, short-pulse laser light. The destruction threshold can be improved even for laser light having a high peak power. Thereby, while having long-term stability, the hollow fiber 1 with high mechanical strength can be provided.

That is, since the hollow fiber 1 according to the embodiment of the present invention transmits light through the hollow region 14, the gold thin film 12, and the transparent thin film, a transmission wavelength band that cannot be used due to a large transmission loss in the quartz optical fiber. It can be used for light transmission and can be used for light transmission with high peak power. Therefore, the hollow fiber 1 according to the present embodiment is, for example, in the far-infrared region (for example, a wavelength of 2 μm or more) in the fields of medical treatment, industrial processing, measurement, analysis (for example, gas composition, concentration analysis), and chemistry. It can be used when carrying out the transmission of light energy such as light. Specifically, the hollow fiber 1 according to the present embodiment is used to transmit laser light such as an Er-YAG laser with a wavelength of 2.94 μm, a CO laser with a wavelength of 5 μm, or a CO ₂ laser with a wavelength of 10.6 μm. Can be used.

  In addition, according to the method for manufacturing the hollow fiber 1 according to the embodiment of the present invention, the amount of the gold nanoparticle solution 40 attached to the inner wall of the capillary 10 is very small, and the extra gold nanoparticle solution 40 is formed at the tip portion. 16 and can be reused for the production of other hollow fibers. Therefore, the utilization efficiency of the gold nanoparticle solution 40 as a raw material is high, the production cost can be greatly reduced, and the production efficiency can be greatly improved.

[Second Embodiment]

  FIG. 3A shows an example of a partial cross section of a hollow fiber according to the second embodiment of the present invention, and FIG. 3B shows an example of a cross section of the hollow fiber taken along line AA.

  The hollow fiber 1a according to the second embodiment is substantially the same as the hollow fiber 1 except that the silver iodide thin film 13 provided in the hollow fiber 1 according to the first embodiment becomes a copper oxide thin film 19. The configuration is provided. Therefore, a detailed description is omitted except for differences.

(Configuration of hollow fiber 1a)
As shown in FIGS. 3A and 3B, a hollow fiber 1a according to the second embodiment of the present invention includes a capillary 10 and a gold thin film 12 provided to cover the inner wall of the capillary 10 having a mirror surface state. And a copper oxide thin film 19 formed by a chemical reaction on the surface of the gold thin film 12 opposite to the surface in contact with the inner wall of the capillary 10, and a protective layer 15 covering the outer surface of the capillary 10. Similar to the silver iodide thin film 12 according to the first embodiment, the copper oxide thin film 19 according to the present embodiment has a function as a transparent thin film with respect to light in the wavelength range of the infrared region.

(Method for producing hollow fiber 1a)
The manufacturing method of the hollow fiber 1a according to the second embodiment is the same as the manufacturing method of the hollow fiber 1 according to the first embodiment until the formation of the gold thin film 12, and the subsequent steps are also substantially the same. . Hereinafter, differences will be described.

  First, a copper thin film is formed on the gold thin film 12 in the same manner as (f) to (h) in FIG. 2C and (i) in FIG. 2D. That is, first, the syringe 20 is attached to the other end 18 of the capillary 10 in which the gold thin film 12 is formed on the inner wall. And the copper (Cu) nanoparticle solution as a 2nd metal nanoparticle solution of predetermined capacity | capacitance is accommodated in the cylinder 20b. In addition, organic solvents, such as hexane, toluene, or tetradecane, can be used as a solvent as a dispersion medium for dispersing copper nanoparticles.

  Then, similarly to (g) and (h) of FIG. 2C, the piston 20a of the syringe 20 is driven in the pushing direction at a constant speed. The copper nanoparticle solution is discharged from the cylinder 20b at a constant speed in accordance with the pushing drive of the piston 20a. Then, the discharged copper nanoparticle solution is injected into the capillary 10. The copper nanoparticle solution injected into the capillary 10 adheres to the surface of the gold thin film 12 formed on the inner wall of the capillary 10 as it moves from the other end 18 of the capillary 10 toward the tip 16. Then, the copper nanoparticle solution not attached to the surface of the gold thin film 12, that is, the excess copper nanoparticle solution is discharged from the tip end portion 16 of the capillary 10 to the outside of the capillary 10 and is stored in the waste liquid container 45.

  Subsequently, the capillary 10 having the copper nanoparticle solution adhered to the surface of the gold thin film 12 is placed in the electric furnace 50 in the same manner as (i) of FIG. 2D. Then, high temperature heat treatment (for example, heat treatment temperature is 250 ° C. to 350 ° C.) is introduced into this capillary while introducing a predetermined concentration of oxygen gas or a gas containing oxygen at a predetermined concentration from the other end 18 of the capillary 10 to the tip portion 16 side. 10 is applied. As a result, the copper nanoparticle solution is sintered and oxidized into copper oxide, and a copper oxide thin film 19 having a thickness of several tens of nm or less is formed on the surface of the gold thin film 12. Thereby, the hollow fiber 1a according to the second embodiment is obtained.

(Modification of manufacturing method of hollow fiber 1a)
The modification of the manufacturing method of the hollow fiber 1a which concerns on 2nd Embodiment is the manufacturing method of the hollow fiber 1a which concerns on 2nd Embodiment, and the process of attaching a copper nanoparticle solution to the surface of the gold thin film 12. The steps are substantially the same, and the subsequent steps are also substantially the same. Hereinafter, differences will be described.

  First, a copper nanoparticle solution is deposited on the gold thin film 12 in the same manner as (f) to (h) in FIG. 2C. Subsequently, as shown in FIG. 2D (i), the capillary 10 having the copper nanoparticle solution adhered to the surface of the gold thin film 12 is placed in the electric furnace 50. Then, a high temperature heat treatment is performed on the capillary 10 while introducing an inert gas (for example, nitrogen gas 60) from the other end 18 of the capillary 10 to the distal end portion 16 side. As a result, the copper nanoparticle solution is sintered, and a copper thin film having a thickness of several tens of nm or less is formed on the surface of the gold thin film 12 as in (j) of FIG. 2D.

  Next, an oxygen gas having a predetermined concentration or a gas containing oxygen at a predetermined concentration is circulated from the other end 18 of the capillary 10 on which the copper thin film is formed toward the tip portion 16, and is formed on the surface of the gold thin film 12. By oxidizing the copper thin film, a copper oxide thin film 19 having a thickness of several tens of nm or less is formed on the surface of the gold thin film 12. Thereby, the hollow fiber 1a according to the second embodiment is obtained.

  While the embodiments of the present invention have been described above, the embodiments described above do not limit the invention according to the claims. In addition, it should be noted that not all the combinations of features described in the embodiments are essential to the means for solving the problems of the invention.

(A) is a fragmentary sectional view of the hollow fiber which concerns on 1st Embodiment, (b) is sectional drawing of the hollow fiber in an AA line. It is a figure which shows the manufacturing process of the hollow fiber which concerns on 1st Embodiment. It is a figure which shows the manufacturing process of the hollow fiber which concerns on 1st Embodiment. It is a figure which shows the manufacturing process of the hollow fiber which concerns on 1st Embodiment. It is a figure which shows the manufacturing process of the hollow fiber which concerns on 1st Embodiment. It is a figure which shows the manufacturing process of the hollow fiber which concerns on 1st Embodiment. It is a figure which shows the manufacturing process of the hollow fiber which concerns on 1st Embodiment. (A) is a fragmentary sectional view of the hollow fiber which concerns on 2nd Embodiment, (b) is sectional drawing of the hollow fiber in an AA line.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1a Hollow fiber 10 Capillary 12 Gold thin film 12a, 13a Surface 13 Silver iodide thin film 14 Hollow region 15 Protective layer 16 Tip part 17 Silver thin film 18 Other end 19 Copper oxide thin film 20 Syringe 20a Piston 20b Cylinder 40 Gold nanoparticle solution 42 Silver nanoparticle solution 44 Iodine solution 45 Waste liquid container 50 Electric furnace 60 Nitrogen gas 70 Organic solvent

Claims (7)

A hollow tube having a hollow region through which light propagates;
A first metal thin film formed on the inner wall of the hollow tube and having chemical stability;
A transparent thin film formed transparently with respect to the wavelength of the light by chemically changing the second metal thin film formed of metal nanoparticles on the surface opposite to the surface in contact with the inner wall of the first metal thin film A hollow fiber comprising: The metal nanoparticles are Ag nanoparticles,
The hollow fiber according to claim 1, wherein the transparent thin film includes silver iodide formed by subjecting a silver thin film formed from the Ag nanoparticles to iodine treatment. The metal nanoparticles are Cu nanoparticles,
The hollow fiber according to claim 1, wherein the transparent thin film includes copper oxide formed by oxidizing a copper thin film formed from the Cu nanoparticles. A first nanoparticle solution in which first metal nanoparticles are dispersed in a solvent is injected into a hollow tube having a hollow region through which light propagates, and the first nanoparticle is injected into the inner wall of the hollow tube. A first nanoparticle solution attaching step for attaching a particle solution;
Forming a first metal thin film having chemical stability on the inner wall from the first nanoparticle solution attached to the inner wall;
A second nanoparticle solution in which second metal nanoparticles are dispersed in a solvent is injected into the hollow tube, and the second nanoparticle solution is attached to the surface of the first metal thin film. A second nanoparticle solution adhering step,
A second metal thin film forming step of forming a second metal thin film on the surface of the first metal thin film from the second nanoparticle solution attached to the surface of the first metal thin film;
A transparent thin film forming material that chemically reacts with the second metal thin film to form a transparent thin film that is transparent to the light is caused to flow into the hollow tube, and the transparent thin film is removed from the second nanoparticle solution. A method for manufacturing a hollow fiber, comprising: a transparent thin film forming step formed on a first metal thin film. The second nanoparticle solution adhesion step uses Ag nanoparticles as the second metal nanoparticles,
In the second metal thin film forming step, an Ag thin film is formed as the second metal thin film from the Ag nanoparticles,
In the transparent thin film forming step, an iodine solution containing iodine is used as the transparent thin film forming substance, and the iodine solution and the Ag thin film are brought into contact with each other for a certain period of time, whereby a silver iodide thin film is formed as the transparent thin film from the Ag thin film. The manufacturing method of the hollow fiber of Claim 4 to form. In the second nanoparticle solution attaching step, Cu nanoparticles are used as the second metal nanoparticles,
In the second metal thin film forming step, a Cu thin film is formed as the second metal thin film from the Cu nanoparticles,
5. The transparent thin film forming step uses oxygen as the transparent thin film forming material, and forms a copper oxide thin film as the transparent thin film from the Cu thin film by bringing the oxygen and the Cu thin film into contact with each other for a predetermined time. The manufacturing method of the hollow fiber of description. A first nanoparticle solution in which first metal nanoparticles are dispersed in a solvent is injected into a hollow tube having a hollow region through which light propagates, and the first nanoparticle is injected into the inner wall of the hollow tube. A first nanoparticle solution attaching step for attaching a particle solution;
Forming a first metal thin film having chemical stability on the inner wall from the first nanoparticle solution attached to the inner wall;
A second nanoparticle solution in which second metal nanoparticles are dispersed in a solvent is injected into the hollow tube, and the second nanoparticle solution is attached to the surface of the first metal thin film. A second nanoparticle solution adhering step,
A hollow fiber comprising: a transparent thin film forming step for forming a transparent thin film transparent to the light from the second nanoparticle solution on the first metal thin film by circulating a gas containing oxygen in the hollow tube Manufacturing method.

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