JP2007016374A - Method for producing conjugated spinning nozzle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method, etc., for producing a conjugated spinning nozzle enhancing the coaxial accuracy of a nozzle hole of each single-layer nozzle. <P>SOLUTION: The method for producing the nozzle comprises the following steps, a step of arranging a first single-layer nozzle 2 in a prescribed position, a step of detecting the central point of the nozzle hole 2a on the upper surface side of the first single-layer nozzle, a step of laminating a second single-layer nozzle 4 onto the first single-layer nozzle, a step of detecting the central point of the nozzle hole 4a on the top surface side of the second single-layer nozzle in the state of the second single-layer nozzle laminated onto the first single-layer nozzle and a step of arranging and fixing the second single-layer nozzle relatively to the first single-layer nozzle so that two points obtained by projecting the central points of the detected first and the second single-layer nozzles onto the reference surface stay within a circular region of ≤50 μm diameter. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a composite spinning nozzle, and more particularly to a method of manufacturing a composite spinning nozzle used for manufacturing a refractive index distribution type optical transmission body.

  A plurality of single-layer nozzles as shown in FIGS. 1 to 3 are stacked as a composite spinning nozzle for concentrically arranging a plurality of materials and spinning a refractive index distribution type optical transmission body or the like into a cylindrical layered structure. Things are known. FIG. 1 is a plan view of such a composite spinning nozzle 1 as seen from the discharge side, and FIG. 2 is a cross-sectional view taken along line II-II in FIG. FIG. 3 is a perspective view of a part of the upper surface and side surfaces of the composite spinning nozzles stacked via the knock pin P. FIG.

  As shown in FIGS. 1 and 2, in the composite spinning nozzle 1, five single-layer nozzles 2, 4, 6, 8, and 10 are stacked. Each single-layer nozzle 2, 4, 6, 8, 10 has nozzle holes 2a, 4a, 6a, 8a, 10a that extend through the single-layer nozzle in the axial direction, and each nozzle hole 2a, 4a. , 6a, 8a and 10a are arranged so as to be positioned on the coaxial line (hereinafter referred to as “nozzle hole center point”), that is, aligned and fixed to each other.

  The first-layer single-layer nozzle 2 discharges the stock solution forming the central layer (first layer) of the shaped cylindrical filament structure to be shaped from the nozzle hole 2a, and the second-layer single-layer nozzle 4 The stock solution for forming the second layer of the filamentous material around one layer is discharged from the nozzle hole 4a. Similarly, the third to fifth single-layer nozzles 6 to 10 discharge the stock solution forming the third to fifth layers of the filamentous body from the nozzle holes 6a to 10a, respectively.

  In order to exhibit the desired optical performance in the filamentous body to be manufactured, the center point of the nozzle hole of each single-layer nozzle is accurately arranged on the coaxial line in the composite spinning nozzle, that is, the nozzle hole of the single-layer nozzle High coaxial accuracy is required.

  As a method of grasping the coaxial accuracy of the nozzle hole center point, Patent Document 1 describes a method of measuring the coordinates of the nozzle hole center point of each single-layer nozzle individually for each layer.

JP 2003-66249 A

  Specifically, for each single-layer nozzle, measure the coordinates of the nozzle hole center point and two fixed reference points (for example, a knock pin as shown in FIG. 3), and superimpose the fixed reference points of each single-layer nozzle. The nozzle hole center point distribution (virtual distribution) in this case is regarded as the nozzle hole center point distribution (actual distribution) of each single layer nozzle in a state where each single layer nozzle is actually stacked on a set of composite spinning nozzles. Is.

  However, since the actual distribution of the nozzle hole center point of each single-layer nozzle when actually stacked on the composite spinning nozzle does not necessarily match the virtual distribution, the method actually stacked single-layer nozzles. In some cases, the coaxial accuracy at the time could not be grasped, and the nozzle hole center point of each single-layer nozzle was not accurately arranged on the coaxial line.

  In addition, each single-layer nozzle is designed so that each nozzle hole is located almost on the same axis when stacked, but (1) there is some space in the fixed parts such as pins, bolts, and jigs. (2) The nozzle hole center point and fixed reference point of each single-layer nozzle are designed according to the limit of the machining accuracy of the machine tool itself used for machining each single-layer nozzle and the human error of the operator. It is difficult to stack single-layer nozzles with the coaxial accuracy required for spinning an optical transmission body due to some deviation from the value, etc., and each single-layer nozzle actually stacked as a composite spinning nozzle It was extremely difficult to grasp the coaxial accuracy of the nozzle hole center point.

  The present invention has been made to solve such problems, and an object of the present invention is to provide a method for producing a composite spinning nozzle that can improve the coaxial accuracy of the nozzle hole of each single-layer nozzle.

  According to the first aspect of the present invention, there is provided a method for manufacturing a composite spinning nozzle in which a plurality of single-layer nozzles having nozzle holes are stacked, and (1) a step of arranging the first single-layer nozzle at a predetermined position. And (2) detecting a center point of the nozzle hole on the upper surface side of the first single-layer nozzle, and (3) laminating a second single-layer nozzle on the first single-layer nozzle; (4) a step of detecting a center point of the nozzle hole on the upper surface side of the second single-layer nozzle in a state where the second single-layer nozzle is stacked on the first single-layer nozzle; In addition, the second single-layer nozzle is positioned with respect to the first single-layer nozzle so that two points obtained by projecting the center points of the first and second single-layer nozzles onto the reference plane fall within a circular region having a diameter of 50 μm or less. A step of arranging and fixing Method for producing a yarn nozzle is provided.

  According to the second aspect of the present invention, there is provided a composite spinning nozzle manufacturing method in which a plurality of single-layer nozzles having nozzle holes are laminated, wherein (1) the first single-layer nozzle is disposed at a predetermined position. And (2) detecting a center point of the nozzle hole on the upper surface side of the first single-layer nozzle, and (3) stacking a second single-layer nozzle on the first single-layer nozzle; (4) detecting the center point of the nozzle hole on the lower surface side of the second single layer nozzle; and (5) the center point of the nozzle hole of the first single layer nozzle and the second single layer nozzle. Arranging and fixing the second single-layer nozzle with respect to the first single-layer nozzle so that the coordinates in the XY plane of the center point of the nozzle hole are within a circular region having a diameter of 50 μm or less; (6) A fixed number of single-layer nozzles are arranged and fixed in a stacked state Until, the above (1) to repeat the steps (5) The method of producing a composite spinning nozzle, wherein there is provided that.

  According to a third aspect of the present invention, there is provided a method for manufacturing a composite spinning nozzle in which a plurality of single-layer nozzles having nozzle holes are laminated, wherein (1) the first single-layer nozzle is disposed at a predetermined position. And (2) a step of detecting a center point of the nozzle hole on the upper surface side of the first single layer nozzle, and (3) a center of the nozzle hole on the lower surface side of the second single layer nozzle in advance with respect to the fixed reference point. A point is detected, and the coordinates of the center point of the nozzle hole of the first single-layer nozzle and the center point of the nozzle hole of the second single-layer nozzle are within a circular region having a diameter of 50 μm or less. Arranging and fixing the second single-layer nozzle with respect to the first single-layer nozzle so as to fit, and (4) until the predetermined number of single-layer nozzles are arranged and fixed in a stacked state ( Repeat steps 1) to (3) The method of producing a composite spinning nozzle, wherein there is provided.

  According to another aspect of the present invention, there is provided a method of manufacturing a cylindrical optical transmission body having a refractive index distribution that changes continuously or discontinuously from a central portion toward an outer peripheral portion. Alternatively, there is provided a method for producing an optical transmission body, characterized in that a cylindrical optical transmission body is produced using the composite spinning nozzle produced by the production method for a composite spinning nozzle according to the second aspect.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the composite spinning nozzle which can improve the coaxial precision of the nozzle hole of each single layer nozzle, and the manufacturing method of the optical transmission body which can obtain a desired optical characteristic are provided.

Hereinafter, a method for producing a composite spinning nozzle according to a preferred embodiment of the present invention will be described in detail with reference to the drawings.
(First embodiment)
The composite spinning nozzle manufactured in this embodiment is the composite spinning nozzle shown in FIGS. In the composite spinning nozzle, the nozzle holes 2a, 4a, 6a, 8a, and 10a coincide with the axes of the single-layer nozzles 2, 4, 6, 8, and 10, respectively.
When assembling the composite spinning nozzle, it is preferable to use a three-dimensional shape measuring device such as a laser microscope in order to measure coordinates in the height direction (Z-axis direction) of the single-layer nozzle. The three-dimensional shape measuring apparatus includes a contact type and a non-contact type, but the non-contact type is preferable in that the single-layer nozzle is not damaged.

First, the first single-layer nozzle 2 constituting the composite spinning nozzle is arranged on the XY stage so that the surface (inflow side surface) 2b opposite to the discharge side surface is in contact with the stage surface as the bottom surface. At this time, the inflow side surface (bottom surface) of the first single-layer nozzle 2 is used as a reference surface. On the other hand, the discharge side surface of the single-layer nozzle 2 is arranged facing upward.
Next, the first single-layer nozzle placed on the XY stage is fixed to the XY stage with an adhesive tape or a fixing jig.

  The XY stage is movable in the XY direction in the horizontal plane, and has an operation range in the XY direction and the height direction sufficient to measure the coordinates of the outer periphery of the nozzle hole of the mounted single-layer nozzle. In addition, it has a function that can measure the coordinates of each part of the object on the stage with a movement accuracy of 1 μm or less in both the XY direction and the height direction.

  It is preferable that the XY stage further emits white light or the like and the nozzle hole can be observed with a CCD camera or an eyepiece. As an apparatus having such a function, for example, there is an XY stage including a laser microscope, a non-contact three-dimensional shape measuring apparatus, and the like.

Next, the center point of the upper surface (discharge side surface) of the first single-layer nozzle 2 in the nozzle hole 2a of the first single-layer nozzle 2 fixed to the XY stage is measured.
The central point of the nozzle hole 2a is measured by detecting three or more XY coordinates on the outer periphery (outer edge) of the nozzle hole 2a, preferably 10 or more in order to increase the measurement accuracy, and the detected XY coordinate group is the most. The approximate perfect circle is a nozzle hole, and the center coordinates of the nozzle hole 2a are calculated. In the present embodiment, the center point of the nozzle hole 2a of the first single-layer nozzle 2 calculated in this way is used as the reference point of the composite spinning nozzle 1.

  The outer periphery of the nozzle hole 2a is detected by continuously measuring the height (Z coordinate) around the outer periphery of the nozzle hole 2a and setting the position where the height (Z coordinate) fluctuates as the outer periphery. At that time, the height (Z coordinate) may be directly measured, or the height (Z coordinate) may be detected based on a threshold value process and two-dimensionally mapped.

  In the case of detection by height measurement, the height around the outer periphery of the nozzle hole 2a is measured at 3 or more, preferably 10 or more measurement points, and the coordinates at which the height becomes lower than the outer periphery are defined as the coordinates of the nozzle hole outer periphery. Detect as. For example, the height measurement is continuously performed from the outside to the inside of the outer periphery of the nozzle hole, and the coordinates of the point at which the height rapidly decreases are set as the coordinates of the outer periphery of the nozzle hole.

When detecting the outer periphery of the nozzle hole, the coordinates on the stage are the same, so it is not necessary to put the entire nozzle hole in one field of view. Further, the method for detecting the outer periphery of the nozzle hole is not limited to the method shown here.
For example, in the case of detection by image processing, an image of the outer periphery of the nozzle hole 2a is captured at 3 or more, preferably 10 or more detection points, and the coordinates of the outer periphery of the nozzle hole 2a are obtained by image processing from the captured image. To detect.

  Next, the second single-layer nozzle 4 is stacked on the first single-layer nozzle 2 so that the nozzle holes 2a and 4a of both the single-layer nozzles 2 and 4 are aligned. At this time, since the first single-layer nozzle 2 is fixed to the XY stage by a tape or a fixing jig, it does not move. In this state, the coordinates of the center point on the upper surface (discharge side surface) of the single-layer nozzle 4 of the nozzle hole 4a of the second single-layer nozzle 4 are the same as the method performed for the first single-layer nozzle. calculate.

  And the point which projected the center point of the nozzle hole 4a of the 2nd single layer nozzle 4 on a reference plane, and the reference point of the composite spinning nozzle 1, ie, the center point of the nozzle hole 2a of the 1st single layer nozzle 2, are used as a reference surface. When it is confirmed that the projected point is within a circular region having a diameter of 50 μm, more preferably 20 μm or less, and even more preferably 10 μm or less, the second single-layer nozzle 4 is moved to the first single-layer nozzle 4 in this state. The single-layer nozzle 2 is fixed with a bolt or the like. If the nozzle hole center point 4a is not within the predetermined circular area, the position of the second single-layer nozzle 4 is adjusted so that the nozzle hole center point 4a is within the circular area, and then the bolt For example, the second single-layer nozzle 4 is fixed to the first single-layer nozzle 2.

Similarly, the third to fifth single-layer nozzles 6, 8, and 10 are sequentially stacked, the coordinates of the nozzle hole center point are calculated for each single-layer nozzle, and the center point is projected onto the reference plane. Each single-layer nozzle is disposed so that the reference point of the composite spinning nozzle 1 is projected on the reference plane within a circular region having a diameter of 50 μm or less, more preferably 20 μm or less, and even more preferably 10 μm or less. In this state, it is fixed to the lower single-layer nozzle.
Thus, by using the single layer nozzle as a composite spinning nozzle, a composite spinning nozzle with high coaxial accuracy of the nozzle hole of each single layer nozzle can be obtained.

  The composite spinning nozzle assembled by the method as described above can be used in the same manner as a conventional composite spinning nozzle to spin a filament having a cylindrical laminated structure such as a refractive index distribution type optical transmission body.

(Second Embodiment)
In the above embodiment, each single-layer nozzle is positioned with respect to the center point of the nozzle hole on the upper surface (discharge) side of the single-layer nozzle. The second embodiment will be described next. To do. In this method, when aligning the nozzle holes of the upper and lower single-layer nozzles, the XY coordinates of the center point on the upper surface (discharge) side of the nozzle holes of the lower single-layer nozzle and the upper single-layer nozzle The XY coordinates of the center point on the lower surface (inflow) side of the single-layer nozzle of the nozzle hole of the upper nozzle unit are within a circular region having a diameter of 50 μm, more preferably 20 μm or less, and even more preferably 10 μm or less. The layer nozzle is positioned with respect to the lower single layer nozzle, and in this state, the upper single layer nozzle is fixed to the lower single layer nozzle with a bolt or the like. -Repeat until fixed. According to this method, the center points of the nozzle holes are aligned at the contact portions of the two single-layer nozzles to be stacked.

  In such a manufacturing method, as shown in FIG. 4, the nozzle holes 4 ″, 6 ″, 8 ″, 10 ″ of the laminated single layer nozzles 4 ′, 6 ′, 8 ′, 10 ′ This is preferably performed when the single-layer nozzles 4 ′, 6 ′, 8 ′, and 10 ′ are inclined with respect to the axis, and the discharge-side center point and the inflow-side center point of the nozzle hole are misaligned. In this case, the deviation of the center point of the nozzle hole on the inflow side and the discharge side is measured in advance, and the deviation is added to the position of the center point on the discharge side of the nozzle hole of the measured upper single-layer nozzle. It is preferable that the center point of the inflow side nozzle hole of the information single layer nozzle and the center point of the discharge side nozzle hole of the lower single layer nozzle are matched.

The deviation of the center point on the inflow side from the center point on the discharge side of the nozzle hole is measured, for example, in the case of a nozzle having a fixed reference point such as a knock pin on the discharge side and the inflow side. The center point on the inflow side with respect to the center point on the discharge side can be calculated by calculating the deviation.
Alternatively, the center point of the discharge side nozzle hole and the center point of the inflow side nozzle hole are obtained with the center point with respect to the nozzle circumference as the origin, and the deviation of the inflow side nozzle hole center point from the discharge side nozzle hole center point is calculated. Good.
Furthermore, if the nozzle holes are different in size on the inflow side and the discharge side, place the nozzle surface on the side with the large nozzle hole on top, find the center coordinates of the upper nozzle hole, and then lower the focus. The deviation can be measured by obtaining the center coordinates of the lower nozzle hole.

  The above-described composite spinning nozzle manufacturing method can be applied to any composite spinning nozzle as long as each single-layer nozzle is provided.

  The present invention is not limited to the above-described embodiment, and various changes or modifications can be made within the scope of the matters described in the claims.

(Composition of composite spinning nozzle)
For shaping the optical transmission body, a composite nozzle having the above-described structure shown in FIG. 1 was used, and a single-hole composite nozzle in which the single-layer nozzles were stacked and fixed with bolts was used.
(Measurement of coaxial accuracy of single-layer nozzle)
The coaxial accuracy was measured by the method of the above embodiment, and the distribution range of the nozzle hole center point of each single layer nozzle was defined as the coaxial accuracy of the nozzle hole of each single layer nozzle.

(Measurement of MTF)
The optical transmission body manufactured using the assembled composite spinning nozzle was used as a rod lens array, and the MTF of this rod lens array 11 was measured by a known method. That is, as shown in FIG. 5, the light from the light source 12, the filter 14, the diffuser plate 16, and one set (one line pair) of a transparent line and a light-shielding (black) line, 12 sets per 1 mm width (spatial frequency: 12 lines) The light is transmitted through a grid 18 arranged in pairs / mm) and is incident on a rod lens array 11 arranged opposite to the grid 18, and the emitted light of the grid image from the rod lens array 11 is read by the CCD line sensor 20. MTF (%) was determined from the maximum and minimum values of the measured light quantity. In addition, MTF was calculated | required about all the optical transmission bodies which comprise the rod lens array 11, and the average value was computed.

Example 1
The coaxial accuracy of the nozzle holes of the first to fifth single-layer nozzles is measured by the assembling method of the above embodiment, and the center point of the nozzle hole is within a predetermined circular region so that the coaxial accuracy is at the optimum position. Each single-layer nozzle was moved to 5 to fix the single-layer nozzles.
As a result, the distribution range of the nozzle hole center point of each single-layer nozzle was within a circular diameter region having a diameter of 20 μm.

  Using the composite spinning nozzle thus assembled, an optical transmitter precursor was produced. Specifically, as a stock solution for forming the first layer (center layer), 52 parts by mass of polymethyl methacrylate (PMMA), 35 parts by mass of benzyl methacrylate (BzMA), 13 parts by mass of methyl methacrylate (MMA), 1-hydroxycyclohexyl phenyl ketone A stock solution prepared by mixing 0.24 parts by mass and 0.1 parts by mass of hydroquinone (HQ) was used as a second layer forming stock solution, 48 parts by mass of PMMA, 10 parts by mass of BzMA, 2, 2, 3, 3, 4, 4, 5 A stock solution prepared by mixing 7 parts by mass of 5-octafluoropentyl methacrylate (8FMA), 35 parts by mass of MMA, 0.26 parts by mass of 1-hydroxycyclohexyl phenyl ketone, and 0.1 parts by mass of HQ was used as a third layer forming stock solution. Part by mass, 23 parts by mass of 8FMA, 30 parts by mass of MMA, 1-hydroxycyclohexyl A stock solution prepared by mixing 0.27 parts by mass of nilketone and 0.1 parts by mass of HQ was used as a fourth layer forming stock solution, 40 parts by mass of PMMA, 42 parts by mass of 8FMA, 18 parts by mass of MMA, 0.3 parts by mass of 1-hydroxycyclohexyl phenyl ketone, HQ 0.1 mass part, dye CY-10 (Nippon Kayaku Co., Ltd. product) 0.5 mass part, dye BlueA-CR (Nippon Kayaku Co., Ltd. product) 2.0 mass part prepared the stock solution which prepared. As a 5-layer forming stock solution, a stock solution prepared by preparing 37 parts by mass of PMMA, 59 parts by mass of 8FMA, 4 parts by mass of MMA, 0.32 parts by mass of 1-hydroxycyclohexyl phenyl ketone, and 0.1 parts by mass of HQ was prepared.

  Each stock solution is supplied to the composite spinning nozzle and simultaneously discharged while being drawn at a speed of 3 m / min. From the central portion to the outer peripheral portion, the first layer forming stock solution to the fifth layer forming stock solution are coaxial cylinders in this order. A thread-like body (light transmission body precursor) having a five-layer laminated structure arranged in a stack was formed. The discharge side opening diameter of the nozzle hole of each single-layer nozzle was 1.5 mm.

Further, while taking this filamentous body under the same speed conditions as described above, an optical transmission body was obtained by passing through a 0.5 m long interdiffusion treatment section and a 1.2 m long photopolymerization curing treatment section.
The MTF of the optical transmission body thus obtained was 45%.

(Example 2)
With the manufacturing method of the second embodiment, the deviation of the center point of the inflow side nozzle hole with respect to the center point of the discharge side nozzle hole in each of the two to five single layer nozzles was measured for five single layer nozzles. Next, while measuring the center point of the nozzle hole of each of the first to fifth single-layer nozzles, the upper layer inflow side nozzle hole center point in contact with the discharge side nozzle hole center point is within the circular region, and the coaxial accuracy is improved. Each single-layer nozzle was moved so as to be in an optimal position, and five single-layer nozzles were fixed.
As a result, the distribution of each discharge-side nozzle hole center point and the upper-layer inflow-side nozzle hole center point in contact with the discharge-side nozzle hole center point was within a circular diameter region having a diameter of 30 μm.

(Comparative example)
A composite spinning nozzle was assembled using the same single-layer nozzle as in the example. However, even when the coaxial accuracy was not good, each single-layer nozzle was fixed without moving the single-layer nozzle so that the coaxial accuracy was good. As a result, the distribution range of the nozzle hole center point of each single-layer nozzle was within a circular region having a diameter of 61 μm.

  Using such a composite spinning nozzle, an optical transmission body was formed in the same manner as in the example. As a result, the MTF of the obtained optical transmission body was 20%.

It is the top view which looked at the compound spinning nozzle from the discharge side. It is sectional drawing along the II-II line of FIG. It is a perspective view of the upper surface and side surface (part) of a composite spinning nozzle. It is sectional drawing explaining the manufacturing method of the composite spinning nozzle by the 2nd Embodiment of this invention. It is drawing which shows the structure of the measuring apparatus of MTF.

Explanation of symbols

1: Composite spinning nozzle 2: Single layer nozzle (first layer)
4: Single-layer nozzle (second layer)
6: Single layer nozzle (third layer)
8: Single layer nozzle (fourth layer)
10: Single layer nozzle (5th layer)
2a, 4a, 6a, 8a, 10a: nozzle holes

Claims (4)

A method for producing a composite spinning nozzle in which a plurality of single-layer nozzles having nozzle holes are laminated,
(1) disposing the first single-layer nozzle at a predetermined position;
(2) detecting a center point of a nozzle hole on the upper surface side of the first single layer nozzle; and (3) laminating a second single layer nozzle on the first single layer nozzle;
(4) detecting a center point of a nozzle hole on the upper surface side of the second single-layer nozzle in a state where the second single-layer nozzle is stacked on the first single-layer nozzle;
(5) The second single-layer nozzle is moved to the first single-layer nozzle so that the two points obtained by projecting the center points of the detected first and second single-layer nozzles onto the reference plane fall within a circular region having a diameter of 50 μm or less. Arranging and fixing to a single-layer nozzle,
A method for producing a composite spinning nozzle. A method for producing a composite spinning nozzle in which a plurality of single-layer nozzles having nozzle holes are laminated,
(1) disposing the first single-layer nozzle at a predetermined position;
(2) detecting a center point of the nozzle hole on the upper surface side of the first single-layer nozzle;
(3) laminating a second single-layer nozzle on the first single-layer nozzle;
(4) detecting the center point of the nozzle hole on the lower surface side of the second single layer nozzle; and (5) the center point of the nozzle hole of the first single layer nozzle and the nozzle of the second single layer nozzle. Arranging and fixing the second single-layer nozzle with respect to the first single-layer nozzle so that the coordinates of the center point of the hole in the XY plane are within a circular region having a diameter of 50 μm or less;
(6) Repeat steps (1) to (5) until a predetermined number of single-layer nozzles are arranged and fixed in a stacked state.
A method for producing a composite spinning nozzle. A method for producing a composite spinning nozzle in which a plurality of single-layer nozzles having nozzle holes are laminated,
(1) disposing the first single-layer nozzle at a predetermined position;
(2) detecting a center point of the nozzle hole on the upper surface side of the first single-layer nozzle;
(3) The center point of the nozzle hole on the lower surface side of the second single-layer nozzle with respect to the fixed reference point is detected in advance, and the center point of the nozzle hole of the first single-layer nozzle and the second single layer Arranging and fixing the second single-layer nozzle with respect to the first single-layer nozzle so that the coordinates of the center point of the nozzle hole of the nozzle are within a circular region having a diameter of 50 μm or less. When,
(4) Steps (1) to (3) are repeated until a predetermined number of single-layer nozzles are arranged and fixed in a stacked state.
A method for producing a composite spinning nozzle. A method of manufacturing a cylindrical optical transmission body having a refractive index distribution that continuously or discontinuously changes from a central portion toward an outer peripheral portion,
Producing a cylindrical optical transmission body using the compound spinning nozzle produced by the method for producing a compound spinning nozzle according to claim 1;
A method of manufacturing an optical transmission body characterized by

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