JP2017178630A - Production method of glass fine particle deposit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method of a glass fine particle deposit capable of measuring accurately the shape of the glass fine particle deposit without depending on location accuracy of a measuring apparatus.SOLUTION: In a production method of a glass fine particle deposit 14, glass fine particles are deposited on a departure rod 13 to produce a glass fine particle deposit 14, and while depositing the glass fine particles, the glass fine particle deposit 14 is irradiated with a laser beam, to thereby measure a curved shape of the surface of the glass fine particle deposit 14, and a measurement result is reflected to a manufacturing condition of the glass fine particle deposit 14.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for producing a glass particulate deposit.

  In general, an optical fiber composed of a core and a clad is manufactured by drawing a glass preform for an optical fiber. A glass base material is formed by depositing glass fine particles generated in a flame of a burner around a rod made of quartz or the like by a VAD method or an OVD method, and then forming the porous glass base material. It is manufactured by heating the material in a dehydration sintering furnace to dehydrate and sinter it into a transparent glass.

  A technique for measuring the outer diameter of a porous glass base material by irradiating the surface of the porous glass base material with a laser beam and receiving the reflected light when manufacturing the porous glass base material is known. (For example, refer to Patent Documents 1 to 5).

JP 2007-153678 A JP 2007-106616 A JP 2006-335622 A JP 2003-277069 A Japanese Patent Laid-Open No. 6-171969

  In the above Patent Documents 1 to 5, the distance between the measuring device and the glass base material that is the object to be measured is measured by a measuring device that irradiates the laser beam and receives the reflected light. Therefore, if the position of the measuring device is deviated during equipment maintenance or the like, it causes a measurement error. Further, when measuring the outer diameter of the glass base material with a laser-type outer diameter measuring instrument or a reading microscope, it is necessary to provide a window having a width larger than the outer diameter of the glass base material in the reaction container for manufacturing the glass base material. This complicates the equipment and increases the cost.

  An object of this invention is to provide the manufacturing method of the glass fine particle deposit body which can measure the shape of the glass fine particle deposit body which is a to-be-measured object accurately, without depending on the positional accuracy of a measuring apparatus.

The method for producing a glass particulate deposit according to the present invention comprises:
A method for producing a glass particulate deposit that produces a glass particulate deposit by depositing glass particulate on a starting rod,
Irradiating the glass fine particle deposit with laser light during the deposition of the glass fine particles, and measuring the curved shape of the surface of the glass fine particle deposit,
The measurement result is reflected in the manufacturing conditions of the glass fine particle deposit.

  According to the present invention, it is possible to accurately measure the shape of the glass particulate deposit without depending on the positional accuracy of the measuring device. Further, since the laser light transmitting window provided in the reaction vessel for producing the glass fine particle deposit body may be small, the equipment is not complicated and the increase in cost can be suppressed.

It is a block diagram of the manufacturing apparatus explaining the manufacturing method of the glass fine particle deposit body which concerns on this invention. It is the elements on larger scale which show the front-end | tip part of the glass particulate deposit shown by FIG.

[Description of Embodiment of Present Invention]
First, the contents of the embodiments of the present invention will be listed and described.
A method for producing a glass particulate deposit according to an embodiment of the present invention,
(1) A method for producing a glass particulate deposit that produces a glass particulate deposit by depositing glass particulate on a starting rod,
Irradiating the glass fine particle deposit with laser light during the deposition of the glass fine particles, and measuring the curved shape of the surface of the glass fine particle deposit,
The measurement result is reflected in the manufacturing conditions of the glass fine particle deposit.
According to this configuration, it is possible to accurately measure the surface shape of the glass fine particle deposit without depending on the positional accuracy of the measuring apparatus, so that deformation or the like of the glass fine particle deposit can be appropriately detected. Further, since the laser light transmitting window provided in the reaction vessel for producing the glass fine particle deposit body may be small, the equipment is not complicated and the increase in cost can be suppressed.

(2) Measure the surface curvature in the direction perpendicular to the central axis of the glass particulate deposit,
Calculate the outer diameter of the glass particulate deposit from the measurement results,
Compare the calculated outer diameter with a preset target value of the outer diameter,
It is preferable to reflect the comparison result in the manufacturing conditions.
According to this configuration, by calculating the outer diameter from the surface curvature of the circumferential surface of the glass fine particle deposit, the outer diameter of the glass fine particle deposit is more accurately controlled without depending on the positional accuracy of the measuring device. be able to.

(3) The method for producing the glass fine particle deposit is a VAD method,
The curved shape is preferably a shape in a direction along the central axis direction of the glass fine particle deposit.
According to this configuration, it is possible to perform stable pulling control by controlling the shape of the taper portion while measuring the longitudinal curve shape of the taper portion of the glass particulate deposit formed by the VAD method.

(4) It is preferable to stop the deposition of the glass particles when the curved shape deviates from a preset target shape.
According to this structure, generation | occurrence | production of inferior goods can be prevented beforehand and the manpower required for monitoring the manufacturing state of a glass particulate deposit can be reduced.

[Details of the embodiment of the present invention]
Hereinafter, an example of an embodiment of a method for producing a glass fine particle deposit according to the present invention will be described with reference to the drawings.

  FIG. 1 is a configuration diagram of a manufacturing apparatus for explaining a method for manufacturing a glass fine particle deposit according to the present embodiment, and FIG. 2 is a partially enlarged view showing a tip portion of the glass fine particle deposit in FIG. As a manufacturing method shown below, a VAD (Vapor Phase Axial Deposition) method will be described as an example, but the present embodiment is not limited to the VAD method. Similarly to the VAD method, the present embodiment can also be applied to a method of depositing glass from a glass raw material using a flame pyrolysis reaction, for example, an OVD (Outside Vapor-phase Deposition) method.

  As shown in FIG. 1, a manufacturing apparatus 10 that performs the method for manufacturing a glass particulate deposit according to this embodiment includes a reaction vessel 11. A support rod 12 is suspended from above the reaction vessel 11 inside the vessel, and a dummy glass rod 13 (an example of a starting rod) is attached to the lower side of the support rod 12. Glass particulates are deposited on the dummy glass rod 13 to form a glass particulate deposit 14. The upper end of the support bar 12 is held by the lifting device 15 and is lifted and lowered by the lifting device 15 together with the rotation. The lifting device 15 is controlled by a pulling control unit 21 in the control device 20. An exhaust pipe 16 is attached to the side wall of the reaction vessel 11.

  A core burner 17 and a clad burner 18 are provided below the inside of the reaction vessel 11. Each of the burners 17 and 18 is supplied with a raw material gas, a combustible gas which is a flame forming gas, an auxiliary combustible gas and the like from a gas supply device 19. The amount of gas supplied from the gas supply device 19 is controlled by the control device 20.

A shape sensor 23 (an example of a measuring device) is installed below the manufacturing apparatus 10. The shape sensor 23 is, for example, a two-dimensional laser measuring device, which irradiates laser light toward the glass fine particle deposit 14 that is an object to be measured, and receives reflected light reflected from the glass fine particle deposit 14. Thus, the surface shape of the glass fine particle deposit 14, for example, the curved shape (surface curvature, etc.) on the outer surface of the glass fine particle deposit 14 can be measured. Specifically, for example, the shape sensor 23 scans and irradiates laser light in a line shape on the glass fine particle deposit 14 that is the object to be measured, and measures the scattered light using the principle of triangulation. The shape of the glass fine particle deposit 14 is measured from the position in the line direction and the depth direction. The result measured by the shape sensor 23 is sent to the outer diameter calculation unit 22 in the control device 20. In the outer diameter calculator 22, the outer diameter of the glass particulate deposit 14 is calculated from the surface shape of the glass particulate deposit 14 measured by the shape sensor 23.
In addition, although it is necessary to provide a window for transmitting the laser beam of the shape sensor 23 below the manufacturing apparatus 10, the window has a width of about ¼ to ½ of the outer diameter of the glass particulate deposit 14. As long as it has. As the window width is larger, the laser beam can be irradiated over a wider range, so that the measurement accuracy is improved. However, the window width may be appropriately selected according to the required accuracy.

  As shown in FIG. 2, the glass particulate deposit 14 includes a first cylindrical portion 31 at the tip, a second cylindrical portion 32 that is a stationary portion, and between the first cylindrical portion 31 and the second cylindrical portion 32. The taper portion 33 is formed. The target values of the deposition shape of the glass particulate deposit 14 (the outer diameter D1 of the first cylindrical portion 31, the outer diameter D2 of the second cylindrical portion 32, and the taper angle θ of the tapered portion 33) are stored in advance in the control device 20. ing.

  As an example, in the method for manufacturing the glass particulate deposit 14 according to the present embodiment, the control device 20 uses the shape sensor 23 during the deposition of the glass particulates to perform the first measurement in the direction perpendicular to the central axis of the glass particulate deposit 14. The surface curvatures of the one cylindrical portion 31 and the second cylindrical portion 32 are measured, and the measurement results are transmitted to the outer diameter calculating portion 22. The outer diameter calculator 22 calculates the outer diameters D1 and D2 of the cylindrical portions 31 and 32 based on the measurement results of the surface curvatures on the circumferential surfaces of the cylindrical portions 31 and 32. In FIG. 1, there is only one shape sensor 23, but the shape sensor 23 may be disposed at a position corresponding to the first cylindrical portion 31 and the second cylindrical portion 32. You may measure by moving up and down.

  The control device 20 controls the pulling rate of the glass particulate deposit 14, the source gas, and / or the so that the outer diameters D1 and D2 calculated by the outer diameter calculating unit 22 are within the preset allowable range. Control the flow rate of flame forming gas. The control device 20 may adjust the pulling speed and the gas flow rate so that the values of the outer diameters D1 and D2 approach the target values. Specifically, the control device 20 (the pulling control unit 21) transmits a control signal to the lifting device 15, and the lifting device 15 adjusts the pulling speed of the glass particulate deposit 14 based on the control signal. Further, the control device 20 transmits a control signal to the gas supply device 19, and the gas supply device 19 determines the supply flow rate of the raw material gas and the flame forming gas to the core burner 17 and the clad burner 18 based on the control signal. Make adjustments. The positions of the core burner 17 and the cladding burner 18 are movable, and the positions of the core burner 17 and the cladding burner 18 relative to the glass particulate deposit 14 are adjusted based on a control signal from the control device 20. May be.

  As described above, according to the manufacturing method of this embodiment, the glass fine particle deposit 14 is irradiated with laser light during the glass fine particle deposition, and the curve shape of the outer surface of the glass fine particle deposit 14 is measured. Is fed back to the manufacturing conditions (pulling speed and gas flow rate) of the glass particulate deposit 14. Thereby, it can control so that the outer diameter of the 1st cylindrical part 31 and the 2nd cylindrical part 32 of the glass fine particle deposition body 14 may be settled in a predetermined | prescribed allowable width | variety. Therefore, a high quality glass base material can be manufactured stably.

  The shape sensor 23 is not only the surface curvature of the circumferential surface of the glass fine particle deposit 14 but also the shape of the tapered portion 33 of the glass fine particle deposit 14 (for example, a curve in the direction along the central axis direction of the glass fine particle deposit 14). It is also possible to measure the shape. In this case, the control device 20 calculates the taper angle θ (see FIG. 2) of the taper portion 33 from the longitudinal curved shape of the taper portion 33 measured by the shape sensor 23. Then, the pulling-up speed of the glass fine particle deposit 14 and the flow rate of the raw material gas and / or the flame forming gas are controlled so that the taper angle θ falls within the allowable width. Thus, by measuring the vertical curved shape of the taper portion 33 and reflecting it in the manufacturing conditions, stable pulling control of the glass particulate deposit 14 can be performed.

  Further, the average height of the taper portion 33 is calculated from the longitudinal curved shape of the taper portion 33 instead of the taper angle θ, and the pulling speed, the source gas, and the like are adjusted so as to keep this average height constant. It is also possible to control the flow rate of the flame forming gas. Such an embodiment is not only applied to the configuration in which the core burner and the cladding burner shown in FIG. 1 are installed, but the starting rod is a core glass rod, and glass particles are deposited on the outside thereof. Application is particularly preferred. In such a configuration, conventionally, the pulling speed is controlled so as to keep the height of a specific point of the tapered portion 33 constant. However, if the tapered portion 33 is uneven, the pulling speed is not stable. There was a problem. On the other hand, by applying the configuration of the present embodiment, the pulling speed is stabilized, and as a result, the effect that the outer diameter of the glass fine particle deposit 14 can be made constant in the longitudinal direction can be obtained.

  When the outer diameters D1 and D2 of the cylindrical portions 31 and 32 and the taper angle θ of the tapered portion 33 measured by the shape sensor 23 deviate from the allowable width of the target value, it is preferable to stop the deposition of glass particles. Also, it is preferable to stop the deposition of the glass fine particles when it is detected that the surface curves of the cylindrical portions 31 and 32 are wobbled, that is, have a wavy shape. In this way, when the deposition shape of the glass particulate deposit 14 deviates from a preset target shape or has an abnormal curve, the deposition shape of the glass particulate deposit 14 is deformed (abnormal). By stopping the deposition of the glass fine particles, it is possible to prevent the occurrence of defective glass fine particle deposits (glass base material for optical fibers).

  Although the invention has been described in detail and with reference to specific embodiments, various changes and modifications can be made without departing from the spirit and scope of the invention.

10: Production apparatus 11: Reaction vessel 12: Support rod 13: Dummy glass rod (starting rod)
14: Glass particulate deposit 15: Lifting device 17: Core burner 18: Clad burner 19: Gas supply device 20: Control device 21: Pull-up control unit 22: Outer diameter calculation unit 23: Shape sensor (measurement device)
31: First cylindrical portion 32: Second cylindrical portion 33: Tapered portion

Claims (4)

A method for producing a glass particulate deposit that produces a glass particulate deposit by depositing glass particulate on a starting rod,
Irradiating the glass fine particle deposit with laser light during the deposition of the glass fine particles, and measuring the curved shape of the outer surface of the glass fine particle deposit
A method for producing a glass particulate deposit, wherein the measurement result is reflected in the conditions for producing the glass particulate deposit. Measure the surface curvature in the direction perpendicular to the central axis of the glass particulate deposit,
Calculate the outer diameter of the glass particulate deposit from the measurement results,
Compare the calculated outer diameter with a preset target value of the outer diameter,
The method for producing a glass particulate deposit according to claim 1, wherein the comparison result is reflected in the production conditions. The method for producing the glass fine particle deposit is a VAD method,
The method for producing a glass particulate deposit according to claim 1, wherein the curved shape is a shape in a direction along a central axis direction of the glass particulate deposit.   The method for producing a glass particulate deposit according to any one of claims 1 to 3, wherein when the curved shape deviates from a preset target shape, the deposition of the glass particulates is stopped.

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