JP2013184864A - Method for manufacturing fluoride image guide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a fluoride image guide, which is fragile and difficult to manufacture, capable of improving the adhesion of fibers, and enabling high pixelation by accurate temperature control.SOLUTION: A method for manufacturing a fluoride image guide includes repeating a process for forming a fiber bundle 5 by filling a plurality of pixel fibers 1 comprising a fluoride to a jacket tube 4 to bundle, a process for forming an image guide preform 7 by heating and extruding the fiber bundle 5, a process for forming an image guide preform bundle 8 by filling the image guide preforms 7 to a jacket tube 9 to bundle, and a process for forming an image guide preform 11 by heating and extruding the image guide preform bundle 8, and also includes a process for further heating and drawing the image guide preform 11, thereby making an image guide 12.

Description

  The present invention relates to a method for manufacturing a fluoride image guide, and for example, relates to a method for manufacturing an image guide for a fluoride glass fiber that is optimal for transmitting infrared light.

  Conventionally, in order to measure the temperature distribution of a measurement object placed in a narrow space, an image guide is used when transmitting light from the object to a thermoviewer or a CCD camera. This type of image guide is manufactured, for example, by a manufacturing method as described in Patent Document 1.

  Specifically, as shown in FIG. 5, first, a heat-shrinkable first synthetic resin tube having a glass rod inserted therein is heated under reduced pressure, and the tube is adhered to the surface of the glass rod. A fiber preform is produced (in some cases, a pixel fiber is produced by drawing) (see FIG. 5A). Next, a heat-shrinkable second synthetic resin tube is filled with the preform or a plurality of fibers obtained by drawing the preform (see FIG. 5B). Next, the second synthetic resin tube is heated to produce a bundle (image guide) preform in which a plurality of preforms or fibers are bundled by thermal contraction of the second synthetic resin tube (see FIG. 5C). ). Finally, the bundle preform is drawn under heating to produce an image guide having a plurality of glass cores inside the first and second synthetic resin tubes as clads (see FIG. 5D). ).

  Furthermore, as a method for manufacturing a fluoride glass preform, the core glass melt is poured into the clad glass melt in a state where the core glass and the clad glass are not mixed, thereby bonding the core and clad interface in the melt state. After cooling and solidifying, the glass obtained by forming the core glass into a convex shape with respect to the clad glass is processed into a shape suitable for extrusion molding, and then formed into a preform shape by extrusion molding (for example, Patent Document 2). reference).

JP 61-42605 A JP-A-5-301732

  By the way, quartz has been used as a material for an image guide fiber (pixel fiber). The light that can be transmitted through the quartz image guide is only visible light. For example, it has been difficult to measure the temperature distribution of the measurement object below 400 ° C. with the quartz image guide. In view of these points, in recent years, fluorides such as fluoride glass have attracted attention as a material for fibers (pixel fibers) instead of quartz.

  However, fluoride is poor in fluidity and brittle compared to quartz. Therefore, when an image guide made of fluoride glass is manufactured by the manufacturing method as described in Patent Document 1, there is a possibility that the pixel fiber is disconnected when drawing a bundle preform in order to improve the adhesion of the fiber.

  Therefore, considering such points, for example, it is preferable to maintain the preform at a temperature of 315 to 320 ° C. during drawing, but an image guide including a large number of pixel fibers is filled with a plurality of pixel fibers. Therefore, the temperature control by the heater has poor responsiveness and makes it difficult to maintain the temperature. Moreover, temperature maintenance becomes difficult in proportion to the number of pixel fibers.

  Furthermore, the manufacturing method described in Patent Document 2 relates to a method for manufacturing a preform for an optical fiber of a single pixel using fluoride glass as a material. Even if it is applied to an image guide having a large number of pixel fibers, there is a problem that it is difficult to form a uniform pixel fiber due to a temperature difference and an internal stress difference between the outside and the center.

  The present invention has been made in view of such problems, and the object of the present invention is to improve the adhesion of fibers and increase the number of pixels in an image guide made of fluoride, which is fragile and difficult to manufacture. It is an object of the present invention to provide a method for manufacturing a fluoride image guide that enables the above-described process. It is another object of the present invention to provide a method for manufacturing a fluoride image guide that can prevent a pixel fiber from being disconnected and manufacture a high-quality image guide at the manufacturing stage.

  In order to achieve the above object, a method for manufacturing a fluoride image guide according to the present invention includes a step of filling a fiber tube with a plurality of fluoride pixel fibers into a jacket tube to form a fiber bundle, and heating and extruding the fiber bundle. A method of manufacturing a fluoride image guide, comprising: forming an image guide preform; and further heating and drawing the image guide preform. In the step of forming the image guide preform, A plurality of formed image guide preforms are filled into a jacket tube to form a bundle, and the bundle is heated and extruded to form an image guide preform.

  The manufacturing method of the fluoride image guide of the present invention configured as described above is intended for fluorides such as fluoride glass that are fragile and difficult to handle with quartz, and have poor fluidity and temperature management. In the step of forming the image guide preform, since the image guide preform is formed by performing two-stage heat extrusion, large heat shrinkage is not given at one time. Therefore, it is possible to prevent the pixel fiber from being cut and increase the adhesion between the pixels, and to manufacture a high-pixel image guide with stable quality.

  As a preferable specific aspect of the method for producing a fluoride image guide according to the present invention, the fiber bundle is extruded along the inclined surface. According to this aspect, when heating and extruding a fiber bundle in which pixel fibers or image guide preforms are bundled, the diameter of the fiber bundle can be gradually reduced along the tapered inclined surface. The degree of adhesion of each pixel fiber can be increased without cutting the fiber.

  Further, as another preferable specific embodiment of the method for producing a fluoride image guide according to the present invention, the step of drawing the image guide preform by heating is performed by causing a heater to face the outer periphery of the image guide preform. The temperature of the image guide preform is detected, and heating is performed while rotating the heater based on the detected temperature. Moreover, in another aspect, it heats by moving to a radial direction, rotating a heater.

  In the manufacturing method of the fluoride image guide configured as described above, the image guide preform is locally heated with a heater facing the outer periphery of the image guide preform, and the temperature at that time is measured, and the heater is measured. Since it rotates and heats, the heating within a preset temperature range is attained in a short time. Further, the heater can be heated close to the radial direction particularly at a low temperature portion, and the heater can be heated away from the high temperature portion, so that efficient heating is possible.

  In addition, it is preferable that the pixel fibers or the image guide preforms are arranged so that the outer diameter of the jacket tube is larger in the state of being filled and bundled in the jacket tube. According to this configuration, when the image guide preform is heated from the outer peripheral side, the temperature increases closer to the heater on the outer peripheral side, and the fluidity is improved in proportion to the temperature. As a result, the image guide preform can be easily deformed, so that (the cross section before drawing / the cross section after drawing) can be increased, so that the image guide preform can be both increased in pixel size and reduced in diameter.

  In the method of manufacturing a fluoride image guide according to the present invention, even when a pixel fiber made of a fragile and difficult-to-manufacture is used, disconnection of the pixel fiber can be prevented at the manufacturing stage, and adhesion of the pixel fiber is prevented. High pixel count can be achieved by improvement and accurate temperature management.

The principal part perspective view which shows the process of one Embodiment of the manufacturing method of the fluoride image guide which concerns on this invention. The longitudinal cross-sectional view of the shaping | molding die used at the preform extrusion process of FIG. The heating means used at the drawing process of FIG. 1 is shown, (a) is sectional drawing of a horizontal direction, (b) is a side view of (a). The horizontal direction sectional view of the preform produced with other embodiments of the manufacturing method of the fluoride image guide concerning the present invention. The principal part perspective view which shows the process of one Embodiment of the manufacturing method of the conventional fluoride image guide.

  Hereinafter, an embodiment of a method for producing a fluoride image guide according to the present invention will be described in detail with reference to the drawings. 1A and 1B show the steps of a method for manufacturing a fluoride image guide according to the present embodiment, wherein FIG. (D) is the second filling process of the image guide preform, (e) is the second manufacturing process of the image guide preform, and (f) is the image guide drawing process. FIG. The series of steps shown in FIGS. 1C to 1D corresponds to the step of forming an image guide preform in the present invention.

  FIG. 1A shows a manufacturing process of a pixel fiber. A pixel fiber preform 2 forming the pixel fiber 1 has a central core 2a having, for example, fluoride glass, fluoride zirconium, fluoride lanthanum, and fluoride aluminum. The outer cladding 2b is made of a fluoride tube. In the present embodiment, a ZBLAN fiber is used as the fluoride as a multi-component glass optical fiber.

  The pixel fiber preform 2 is formed in a cylindrical shape having a diameter of, for example, about 10 mm. The diameter of the preform 2 is reduced by drawing it through the heating furnace 3, and the pixel fiber 1 having a diameter of about 100 μm to 500 μm is drawn. Form.

  The small-diameter pixel fiber 1 thus formed has a shape in which a central core 1a is covered with an outer cladding 1b. When this fluoride fiber is crystallized, the transmittance tends to be extremely lowered, and the purpose of this embodiment is not to lower the transmittance.

  In the first filling process of the pixel fiber shown in FIG. 1B, the pixel fiber having a diameter of about 500 μm formed in the previous process is formed inside the jacket tube 4 having an outer diameter of about 25 to 30 mm formed of fluoride. For example, about 2500 are inserted and filled, and a large number of pixel fibers are bundled with a jacket tube 4 to produce a fiber bundle 5.

  In the first process for producing the image guide preform shown in FIG. 1C, the fiber bundle 5 produced in the previous process is heated at 315 to 320 ° C. and the diameter thereof is reduced, and the diameter is 25 to 30 mm. An image guide preform 7 is formed through a mold 6 that reduces the diameter of the fiber bundle 5 to about 8 to 10 mm.

  The mold 6 whose diameter is reduced in the first image guide preform manufacturing process has a tapered structure as shown in FIG. 2, and has a conical slope so that the diameter of the fiber bundle 5 can be gradually reduced. Surface 6a is formed.

  For this reason, the fiber bundle 5 is heated, pressurized from above via the piston 6b, passes through the inclined surface 6a of the mold 6, and the fiber bundle 5 is extruded as an image guide preform 7 along the inclined surface 6a. Therefore, the small-diameter image guide preform 7 is formed by extrusion. The image guide preform 7 has a diameter of about 9.5 mm in this embodiment. Note that the image guide preform 7 may be configured to be reduced in diameter so that the outer periphery is formed in a hexagonal column shape.

  The image guide preform 7 thus formed in the first image guide preform manufacturing process is further bundled and imaged in the second filling process for filling the image guide preform shown in FIG. The guide preform bundle 8 is used. Specifically, a large number (about 40) of the image guide preform 7 having a diameter of 9.5 mm in the previous process is inserted into a jacket tube 9 made of Teflon (registered trademark), and the image guide has a diameter of about 50 mm. A preform bundle (a fiber bundle using an image guide preform as a fiber) 8 is formed.

  The image guide preform bundle 8 formed in this way is heated and pressurized from above through the piston 10a in the process of producing the second image guide preform shown in FIG. 1 (e). The image guide preform 11 is passed through the mold 10 and reduced in diameter to about 8 to 10 mm. Specifically, the image guide preform bundle 8 heated at 315 to 320 ° C. and bundled to a diameter of 50 mm is formed on the image guide preform 11 having a diameter of 9.5 mm.

  The mold 10 used in the second image guide preform process has basically the same taper structure as the mold 6 used in the first process, and the image guide preform bundle 8 follows the inclined surface. Extruded. The first mold 6 has a diameter of about 25 to 30 mm and is reduced to about 9.5 mm, whereas the second mold 10 has a diameter of about 50 mm to about 9.5 mm. . The image guide preform 11 whose diameter has been reduced by the molding die 10 may be configured such that the outer diameter is reduced to a hexagonal column shape in the same manner as the molding die 6 described above.

  The image guide preform 11 formed by heating and pressing in the second image guide preform manufacturing process is formed on the small-diameter image guide 12 in the image guide drawing process shown in FIG. The Specifically, the image guide preform 11 having an outer diameter of about 9.5 mm has an outer diameter of about 1 to 2 mm in a line-cited heating furnace 13 heated in the range of 315 to 320 ° C. In the embodiment, the image guide 12 is drawn with a diameter reduced to 1.4 mm, and a large number of extremely small pixel fibers 1 are bundled.

  The drawing process shown in FIG. 1 (f) will be described in detail with reference to FIG. In this drawing process, the image guide preform 11 is heated in the heating furnace 13 at a temperature range of 315 to 320 ° C. Around the image guide preform 11, a heater 15 having a radiation thermometer 14 as a center is disposed so as to face the heater 15, and the heater 15 can move in a circular manner along the outer periphery of the preform 11 as shown in the circumferential direction A. As shown in the radial direction B of the image guide preform 11, the image guide preform 11 can move linearly. The heater 15 has a shape smaller than the outer diameter of the image guide preform 11, and does not heat the entire outer periphery of the object to be heated, but locally heats it. Therefore, the temperature of the heated part is measured by the radiation thermometer 14, and the heater 15 is turned (rotated) or moved away (moved in the radial direction) based on the temperature, and the object to be heated is set to the set temperature. It is controlled to become.

  The heater 15 is controlled so as to be within a set temperature range, and the heating of the image guide preform 11 that is the object to be heated by the heater rotates the heater 15 in the circumferential direction A. At the same time, it is performed by moving the image guide preform along the radial direction (direction of the rotation radius) B. The radiation thermometer 14 incorporated in the heater 15 is preferably a fiber type.

  The operation of the manufacturing method of the fluoride image guide of the present embodiment configured as described above will be described below. In the method of manufacturing the fluoride image guide configured as described above, as shown in FIG. 1A, the pixel fiber preform 2 is passed from above the heating furnace 3 and heated in a set temperature range. By drawing out, the pixel fiber preform 2 having the core 2a and the clad 2b is reduced in diameter, and the pixel fiber 1 in which the clad 1b is coated around the core 1a is manufactured.

  Next, in the first filling process of the pixel fiber of FIG. 1B, a large number of pixel fibers 1 are inserted into the jacket tube 4 and filled, and the fiber bundle 5 is bundled to produce the fiber, FIG. In the first image guide preform production step, the temperature range is set to 315 to 320 ° C., the fiber bundle 5 is passed through the mold 6 and the diameter is reduced to produce the thin image guide preform 7.

  Further, in this image guide preform manufacturing process, the mold 6 for reducing the diameter has a tapered structure, and the large-diameter fiber bundle 5 is smoothly reduced in diameter along the conical inclined surface 6a so as to have a small-diameter image. Since it becomes the guide preform 7, the image fiber preform 7 having high quality can be manufactured without increasing the degree of adhesion of the pixel fiber and without disconnecting the pixel fiber.

  A plurality of image guide preforms 7 manufactured in this way are filled in the jacket tube 9 and bundled into an image guide preform bundle 8 in the second filling step of FIG. The image guide preform bundle 8 filled and bundled is heated and pressed by the mold 10 in the second image guide preform manufacturing step of FIG. 1E, and the large diameter is reduced to the small diameter. And extruded. Even in the second image guide preform manufacturing process by this pressure extrusion, the mold 10 has a tapered shape having an inclined surface, and is smoothly extruded to form a small-diameter image guide preform 11. For this reason, problems, such as disconnection of a pixel fiber, can be eliminated.

  In this way, in the first filling step, the pixel fibers are bundled by passing them through the jacket tube 4 to produce a fiber bundle 5, and the fiber bundle 5 is heated to a smaller diameter by heat extrusion in the first image guide preform production step. Since the image guide preform 7 is produced by squeezing and the filling process and the image guide preform production process are repeated, it is not necessary to greatly reduce the diameter at one time, and there is a problem such as disconnection of the pixel fiber or the image guide preform. Can be prevented.

  In the drawing process, the image guide preform 11 in which a large number of pixel fibers are bundled is heated by a heater 15 equipped with a radiation thermometer 14, and this heater is rotated and moved along the outer periphery of the image guide preform 11. Since the rotation is controlled based on the temperature measured at 14, uniform heating is possible.

  Further, since it can move in the radial direction, the temperature can be adjusted in a short time by approaching and retreating, and the quality at the time of forming the image guide preform 11 into the narrow image guide 12 can be stabilized. it can.

  Since the heater 15 is moved on the outer periphery of the image guide preform 11, temperature control with high responsiveness is possible by controlling the moving speed. Further, by moving the heater 15 in the radial direction, the temperature of the image guide preform 11 can be lowered or raised, and the responsiveness can be further enhanced.

  Another embodiment of the present invention will be described in detail with reference to FIG. FIG. 4 is a cross-sectional view of another embodiment of an image guide preform filled and bundled with pixel fibers or an image guide preform filled and bundled with an image guide preform in the method of manufacturing a fluoride image guide according to the present invention. is there. In addition, this embodiment is characterized in that the diameter of the pixel fiber or the image guide preform is gradually increased from the center of the image guide preform toward the outer periphery, as compared to the above-described embodiment.

  In FIG. 4, the fiber bundle 21 for bundling and filling the pixel fibers is formed such that the diameter of the pixel fiber 22 located at the center is small in the state of being filled and bundled in the jacket tube, and the diameter gradually increases toward the outer periphery. It is arranged to be. That is, the pixel fiber 23 positioned on the outer circumference of the center pixel fiber 22 is set to have a larger diameter than the center pixel fiber 22, and the pixel fiber 24 positioned on the outer circumference is set to have a larger diameter. The outermost pixel fiber 25 is set to the largest diameter.

  When the fiber bundle 21 configured as described above is heated to form an image guide preform, the heater 15 is heated from the outer peripheral side, so that the outer peripheral side is heated to a higher temperature. For this reason, the thick pixel fiber 25 on the outer peripheral side becomes higher in temperature, and the fluidity is improved and is easily deformed. Further, the inner small-diameter pixel fibers 24, 23, and 22 are likely to reach a predetermined temperature even if the heating amount is small, and the temperature rise is uniform as a whole. Thereby, the manufacturing quality of the image guide preform can be stabilized. As a result, the density of the pixel fiber and the diameter of the image guide preform can be reduced.

  In the above description, the pixel fiber is arranged so that its diameter increases toward the outer peripheral side. However, an image guide preform bundle in which an image guide preform in which pixel fibers are bundled and filled is bundled is shown. Alternatively, the jacket tube may be arranged so that the outer diameter of the jacket tube is larger in diameter when the jacket tube is filled and bundled. Even in this configuration, since the image guide preform on the outer peripheral side is heated to a high temperature, similarly to the above, the fluidity is improved and the image guide preform is easily deformed, and the manufacturing quality of the image guide preform can be stabilized.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various designs can be made without departing from the spirit of the present invention described in the claims. It can be changed.

  For example, although an example in which the process of heating and extruding a bundle of pixel fibers or image guide preforms to produce a preform has been described twice, it may be configured to be performed three or more times. In short, by performing extrusion molding a plurality of times, the strain at each time can be reduced, and a high-quality image guide preform can be manufactured.

1: Pixel fiber 2: Pixel fiber preform 3: Heating furnace 4: Jacket tube 5: Fiber bundle 6: Mold 7: Image guide preform 8: Image guide preform bundle 9: Jacket tube 10: Mold 11: Image Guide preform 12: Image guide 13: Heating furnace 14: Radiation thermometer 15: Heater 21: Fiber bundles 22, 23, 24, 25: Pixel fiber

Claims (5)

Filling and bundling a plurality of pixel fibers made of fluoride into a jacket tube to form a fiber bundle, heating and extruding the fiber bundle to form an image guide preform, and further heating the image guide preform A method of manufacturing a fluoride image guide including a drawing step,
In the step of forming the image guide preform, a step of forming a bundle in which a plurality of the formed image guide preforms are filled and bundled in a jacket tube, and the bundle is heated and extruded to form an image guide preform. A method for producing a fluoride image guide, comprising:   2. The fluoride according to claim 1, wherein a mold for heating and extruding the fiber bundle is a tapered mold having a conical inclined surface, and the fiber bundle is extruded along the inclined surface. Image guide manufacturing method.   The step of drawing the image guide preform by heating is such that a heater is opposed to the outer periphery of the image guide preform, the temperature of the image guide preform is detected, and the heater is rotated based on the detected temperature. The method for producing a fluoride image guide according to claim 1, wherein the heating is performed while heating.   4. The method of manufacturing a fluoride image guide according to claim 3, wherein the heating is performed by moving the heater in a radial direction while rotating the heater.   The pixel fiber or the image guide preform is arranged in such a manner that the outer diameter of the jacket tube is larger in a state of being filled and bundled in the jacket tube. The manufacturing method of the fluoride image guide in any one.

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