Optical fiber preform manufacturing apparatus and method for manufacturing optical fiber preform

Abstract

To insulate radiant heat from a burner part.SOLUTION: A manufacturing apparatus of an optical fiber preform includes a burner part for blowing flame containing glass soot generated from raw material gas for the optical fiber preform, against a rod-like starting base material, a moving mechanism for moving the burner part along a longer direction of the starting base material, a belt-like heat shielding member moving together with the burner part, and multiple rollers over which the heat shielding member is spread.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an apparatus for manufacturing an optical fiber preform and a method for manufacturing an optical fiber preform. [Background technology]

[0002] Patent Document 1 discloses an apparatus for manufacturing an optical fiber preform in which a burner unit moves back and forth along the longitudinal direction of a starting substrate and blows a flame containing glass soot onto the outer peripheral surface of the optical fiber preform. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2004-315282 A Summary of the Invention [Problem to be solved by the invention]

[0004] Generally, the time required for the manufacturing process of the optical fiber preform increases as the size of the optical fiber preform to be manufactured increases. As a result, the amount of heat generated in the device increases, causing the problem that the mechanical parts and electronic devices in the device are deteriorated by the radiant heat from the burner.

[0005] The present invention has been made in consideration of the above-mentioned problems, and has an object to provide an optical fiber preform manufacturing apparatus and an optical fiber preform manufacturing method capable of blocking radiant heat from a burner portion. [Means for solving the problem]

[0006] According to one aspect of the present invention, there is provided a burner unit which blows a flame containing glass soot generated from a raw material gas of an optical fiber preform onto a rod-shaped starting substrate, a moving mechanism which moves the burner unit along the longitudinal direction of the starting substrate, a strip-shaped heat insulating member which moves integrally with the burner unit, and a plurality of rollers around which the heat insulating member is stretched. a tension applying mechanism that applies tension to the heat insulating member;Equipped with The tension applying mechanism drives at least one of the rollers to adjust the distance between the rollers. The present invention provides an apparatus for manufacturing an optical fiber preform.

[0007] According to another aspect of the present invention, a method for producing an optical fiber preform includes the steps of blowing a flame containing glass soot generated from a raw material gas of the optical fiber preform from a burner unit onto a rod-shaped starting substrate, and moving the burner unit along the longitudinal direction of the starting substrate, and a strip-shaped heat insulating member is stretched over a plurality of rollers and moves integrally with the burner unit. a tension applying mechanism that applies tension to the heat shield, and the tension applying mechanism drives at least one of the plurality of rollers to adjust a distance between the rollers. The present invention provides a method for producing an optical fiber preform. Effect of the Invention

[0008] According to the present invention, there are provided an apparatus for manufacturing an optical fiber preform and a method for manufacturing an optical fiber preform, which are capable of blocking radiant heat from a burner unit. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic diagram showing an overall configuration of an apparatus for manufacturing an optical fiber preform according to a first embodiment. [Diagram 2] FIG. 2 is a perspective view illustrating an internal structure of the apparatus for manufacturing the optical fiber preform according to the first embodiment. [Diagram 3] 3 is a schematic diagram illustrating a structure for applying tension to a heat shielding curtain in the apparatus for manufacturing an optical fiber preform according to the first embodiment. FIG. [Figure 4A] 3A to 3C are schematic diagrams illustrating forces acting between a heat shielding curtain and a burner unit in the apparatus for manufacturing an optical fiber preform according to the first embodiment. [Figure 4B] 3A to 3C are schematic diagrams illustrating forces acting between a heat shielding curtain and a burner unit in the apparatus for manufacturing an optical fiber preform according to the first embodiment. [Diagram 5] 1 is a block diagram showing a schematic configuration of a control system of an optical fiber preform manufacturing apparatus according to a first embodiment. [Figure 6] 4 is a flowchart showing an example of a process for forming glass soot in the apparatus for manufacturing an optical fiber preform according to the first embodiment. [Figure 7] FIG. 2 is a perspective view illustrating an internal structure of a manufacturing apparatus that is a comparative example to the manufacturing apparatus of the optical fiber preform according to the first embodiment. [Figure 8] 10 is a schematic diagram illustrating a structure for applying tension to a heat shielding curtain in the optical fiber preform manufacturing apparatus according to the second embodiment. FIG. [Figure 9] FIG. 11 is a schematic diagram showing an overall configuration of an apparatus for producing an optical fiber preform according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the drawings described below, parts having the same functions are designated by the same reference numerals, and repeated description thereof will be omitted.

[0011] 1 is a schematic diagram showing the overall configuration of an apparatus 100 for manufacturing an optical fiber preform 10 according to the present embodiment. In the present embodiment, the apparatus 100 manufactures the optical fiber preform 10 by depositing glass soot on the outer peripheral surface of a starting substrate by an OVD method (outside vapor deposition method). In addition, the term "optical fiber preform" in this specification is a general term for a porous glass preform for optical fiber (porous optical fiber preform) and a preform obtained by sintering and vitrifying a porous glass member.

[0012] As shown in FIG. 1, the manufacturing apparatus 100 includes a reaction vessel 101, a spindle mechanism 102, a chuck 103, a target rod 104, a dummy rod 105, a burner 106, a guide rail 107, a traverse motor 108, a pair of rollers 109a, 109b, a roller position moving mechanism 110, and a heat shielding curtain 111.

[0013] The manufacturing apparatus 100 further includes a raw material gas supplying apparatus 112 , a raw material gas supplying line 113 , a carrier gas supplying apparatus 114 , a carrier gas supplying line 115 , a combustion gas supplying apparatus 116 , a combustion gas supplying line 117 , and an exhaust mechanism 118 .

[0014] The spindle mechanism 102 is connected to both ends of a target rod 104 serving as a starting substrate via a pair of chucks 103, and holds the target rod 104 in a rotatable manner.

[0015] In addition, the spindle mechanism 102 drives the target rod 104, for example, in a horizontal direction, in accordance with instructions from a control system (the control unit 200 described later), thereby loading and unloading the optical fiber preform 10 into and from the reaction vessel 101.

[0016] Furthermore, the spindle mechanism 102 rotates the target rod 104 in a rotation direction R with the target rod 104 as a rotation axis in accordance with instructions from the control system.

[0017] The dummy rod 105 is a rod-shaped member that is fused and fixed to both ends of the target rod 104. The spindle mechanism 102 rotates the dummy rod 105 and the target rod 104 that are held by a pair of chucks 103.

[0018] The burner 106, in accordance with instructions from the control system, forms a flame FL with the combustion gas supplied from the combustion gas supply device 116. In this specification, the burner 106 is also referred to as a "burner section."

[0019] Furthermore, the burner 106 forms glass soot (glass particles) by, for example, hydrolyzing the raw material gas supplied from the raw material gas supply device 112 in the above-mentioned flame FL, and blows the flame FL containing the glass soot onto the target rod 104. As a result, the burner 106 deposits the glass soot on the target rod 104 to form the optical fiber preform 10.

[0020] For example, the optical fiber preform 10 manufactured by the manufacturing apparatus 100 is composed of a target rod 104 and a deposition soot 104a. In the OVD process, the target rod 104 as a starting substrate is a portion that will become the core and part of the cladding of the optical fiber. The deposition soot 104a is formed on the outer periphery of the target rod 104. The deposition soot 104a is a portion that will become the cladding of the optical fiber.

[0021] The traverse motor 108 rotates to move the burner 106 back and forth along the guide rail 107. The guide rail 107 is a member installed parallel to the longitudinal direction L of the target rod 104. The guide rail 107 has, for example, a spiral groove formed on its outer periphery. In addition, a groove that fits into the groove of the guide rail 107 is formed in the base portion of the burner 106. Therefore, when the guide rail 107 rotates due to the rotation of the traverse motor 108, the burner 106 moves. In this way, the traverse motor 108 and the guide rail 107 constitute a movement mechanism for the burner 106.

[0022] The pair of rollers 109a, 109b are disposed opposite to each other with a guide rail 107 therebetween, which is the moving area of ​​the burner 106. A heat insulating curtain 111 is hung between the pair of rollers 109a, 109b. The pair of rollers 109a, 109b rotates due to the force received from the heat insulating curtain 111 when the burner 106 and the heat insulating curtain 111 move together.

[0023] In FIG. 1, the roller position movement mechanism 110 is connected to each of the pair of rollers 109a, 109b. The roller position movement mechanism 110 can move each of the pair of rollers 109a, 109b in the horizontal direction as shown by the arrow. However, the roller position movement mechanism 110 does not have to move both of the rollers 109a, 109b. That is, the roller position movement mechanism 110 adjusts the distance between the pair of rollers 109a, 109b by driving at least one of the pair of rollers 109a, 109b. In this way, the roller position movement mechanism 110 of this embodiment constitutes a tension application mechanism that applies tension to the heat shielding curtain 111 in the direction of the arrow (horizontal direction).

[0024] The heat shielding curtain 111 is a strip-shaped heat shielding member that moves together with the burner 106 along the longitudinal direction L of the target rod 104. The heat shielding curtain 111 is preferably made of a material that has both heat shielding properties (thermal insulation properties) that can sufficiently shield the radiant heat from the burner 106 and flexibility that allows it to be wound around the pair of rollers 109a, 109b.

[0025] Fig. 2 is a perspective view for explaining the internal structure of the manufacturing apparatus 100 for the optical fiber preform 10 according to the present embodiment. For the sake of convenience, the guide rails 107, the traverse motor 108, and the like are omitted from Fig. 2. The dashed line in the figure indicates an example of the direction of heat transfer within the apparatus.

[0026] 2, the burner 106 and the heat shielding curtain 111 are integrated. The emitting portion of the flame FL in the burner 106 passes through a through hole 111a formed in the heat shielding curtain 111 and protrudes toward the target rod 104 side.

[0027] 2 shows an example in which a heat-shielding object T to be shielded from radiant heat from the burner 106 is placed in a space inside a heat-shielding curtain 111 formed in an endless belt shape. Specific examples of the heat-shielding object T include piping such as the above-mentioned raw material gas supply line 113, carrier gas supply line 115, and combustion gas supply line 117, as well as electronic devices (not shown), machine parts, control cables, and the like. Note that the placement of the heat-shielding object T is not limited to this. It is sufficient that the heat-shielding object T is placed on the opposite side of the heat-shielding curtain 111 to the target rod 104.

[0028] FIG. 3 is a schematic diagram for explaining a structure for applying tension to the heat shielding curtain 111 in the manufacturing apparatus 100 for the optical fiber preform 10 according to the present embodiment. The roller position moving mechanism 110 drives at least one of the pair of rollers 109a and 109b to adjust the distance between the rollers. For example, as shown in FIG. 3, when the roller position moving mechanism 110 drives the roller 109a in the direction of the arrow C1 (leftward) and the roller 109b in the direction of the arrow C2 (rightward), the distance between the pair of rollers 109a and 109b increases, and tension is applied to the heat shielding curtain 111. Conversely, when the roller position moving mechanism 110 drives the roller 109a in the rightward direction and the roller 109b in the leftward direction, the distance between the pair of rollers 109a and 109b decreases, and the tension applied to the heat shielding curtain 111 decreases.

[0029] 4A and 4B are schematic diagrams for explaining the forces acting between the heat shielding curtain 111 and the burner 106 in the optical fiber preform manufacturing apparatus 100 according to this embodiment. As shown in Fig. 4A, when the burner 106 moves in the direction of the arrow A, the heat shielding curtain 111 receives a pushing force from the end P of the burner 106 along the longitudinal direction L and moves in the direction of the arrow D. At the same time, the heat shielding curtain 111 receives a pulling force from the end Q of the burner 106 along the longitudinal direction L and moves in the direction of the arrow E. The pushing force and the pulling force are in the same direction.

[0030] 4B, when burner 106 moves in the direction of arrow B, heat insulating curtain 111 receives a pushing force from end Q of burner 106 along longitudinal direction L and moves in the direction of arrow F. At the same time, heat insulating curtain 111 receives a pulling force from end P of burner 106 along longitudinal direction L and moves in the direction of arrow G. The directions of the pushing force and the pulling force are the same.

[0031] The raw material gas supplying device 112 supplies raw material gas for synthesizing an optical fiber preform to the burner 106 via a mass flow controller (not shown) and a raw material gas supplying line 113 in accordance with an instruction from the control system.

[0032] As the source gas, for example, octamethylcyclotetrasiloxane, hexamethyldisiloxane, hexamethylcyclotrisiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, trimethoxymethylsilane, tetramethoxysilane, or the like can be used.

[0033] The carrier gas supply device 114 supplies a carrier gas to the burner via a mass flow controller (not shown) and a carrier gas supply line 115 in accordance with an instruction from the control unit 200. The carrier gas is mixed with the raw material gas in the burner .

[0034] As the carrier gas, an inert gas such as nitrogen, argon, or helium, a mixed gas of oxygen and an inert gas, or oxygen can be used.

[0035] The combustion gas supply device 116, in accordance with instructions from the control system, supplies combustion gas to the burner 106 via a mass flow controller (not shown) and a combustion gas supply line 117. The combustion gas includes, for example, hydrogen and oxygen.

[0036] The exhaust mechanism 118 is installed facing the guide rail 107 so as to face the guide rail 107 via the target rod 104. The exhaust mechanism 118 may have an exhaust hood (not shown) over the entire moving area (movable range) of the burner 106 along the horizontal direction in order to collect exhaust gas after combustion of the flame FL by the burner 106 to an exhaust port.

[0037] The exhaust mechanism 118 also has a pump and a valve (not shown), and by driving the pump according to instructions from the control unit 200, a flow of gas (exhaust gas G1) from the intake side to the exhaust side of the reaction vessel 101 is formed, and the inside of the reaction vessel 101 is exhausted. That is, the excess glass soot that could not be deposited on the target rod 104 is exhausted by the exhaust mechanism 118. This makes it possible to stabilize the flame FL of the burner 106.

[0038] 5 is a block diagram showing a schematic configuration of a control system according to this embodiment. The control unit 200 is a control device having a CPU (Central Processing Unit) 201 that executes various processing operations such as calculations, controls, and discrimination, and a ROM (Read Only Memory) 202 that stores various control programs executed by the CPU 201. The control unit 200 further has a RAM (Random Access Memory) 203 that temporarily stores data during processing operations of the CPU 201, input data, and the like, and a non-volatile memory 204 such as an HDD (Hard Disk Drive) or SSD (Solid State Drive).

[0039] In addition, the control unit 200 is connected to an input operation unit 205 including a keyboard or various switches for inputting predetermined commands or data, and a display unit 206 (e.g., a liquid crystal display or an organic EL display) for displaying various information including the input / setting status of the manufacturing equipment 100.

[0040] The control unit 200 is also connected to the spindle mechanism 102, the burner 106, the traverse motor 108, the roller position moving mechanism 110, the raw material gas supply device 112, the carrier gas supply device 114, the combustion gas supply device 116, and the exhaust mechanism 118 via drive circuits 207a to 207h. In this manner, each device of the manufacturing apparatus 100 is controlled by the control unit 200.

[0041] Hereinafter, the operation of the manufacturing apparatus 100 configured as described above will be described with reference to the drawings.

[0042] 6 is a flow chart showing an example of a process for forming glass soot in the manufacturing apparatus 100 for the optical fiber preform 10 according to the present embodiment. Note that this process is only an example and can be changed as desired.

[0043] First, the control unit 200 controls the spindle mechanism 102 to carry the target rod 104, which is a starting substrate, into the reaction vessel 101 (step S101), and places the target rod 104 at a predetermined position (step S102).

[0044] Next, the control unit 200 refers to the manufacturing conditions stored in the ROM 202 or the RAM 203, and starts the glass soot forming process (step S103).

[0045] In the glass soot forming step, the control unit 200 deposits glass soot on the outer circumferential surface of the target rod 104 (step S104).

[0046] Specifically, in the glass soot forming step, the control unit 200 controls the spindle mechanism 102 to rotate the target rod 104 in a rotation direction R with the target rod 104 serving as a rotation axis.

[0047] In the glass soot forming step, the control unit 200 controls the combustion gas supply device 116 to supply combustion gas to the burner 106 to form a flame FL in the burner 106, and also hydrolyzes the glass raw material gas supplied from the raw material gas supply device 112 to the burner 106 in the flame FL to form glass soot (glass particles), and blows the flame FL containing the glass soot onto the target rod 104. As a result, glass soot is deposited on the outer circumferential surface of the target rod 104.

[0048] Next, the control unit 200 moves the burner 106 and the heat shielding curtain 111 back and forth together along the longitudinal direction L of the starting substrate (the target rod 104) (step S105).

[0049] Specifically, when the position of the burner 106 moving along the longitudinal direction L of the target rod 104 reaches the left end or the right end of the target rod 104, the control unit 200 controls the rotation of the traverse motor 108 to reverse the moving direction of the burner 106. By repeating the reciprocating motion, glass soot is deposited on the outer circumferential surface of the target rod 104 with a uniform thickness in the longitudinal direction L.

[0050] In addition, the heat shielding curtain 111 is hung over a pair of rollers 109a, 109b and is integrated with the burner 106. When the burner 106 moves along the longitudinal direction L, the heat shielding curtain 111 also moves in the same direction, so that the pair of rollers 109a, 109b rotate along with the movement of the heat shielding curtain 111. The heat shielding curtain 111 can move smoothly by the rotation of the pair of rollers 109a, 109b.

[0051] Next, the control unit 200 determines whether the elapsed time has reached the end time of the glass soot forming process (step S106).

[0052] Here, when the control unit 200 determines that the elapsed time is the end time (step S106: YES), the process proceeds to step S107.

[0053] On the other hand, if the control unit 200 determines that the elapsed time is not the end time (step S106: NO), the process returns to step S104.

[0054] Next, the control unit 200 ends the glass soot formation process (step S107). Specifically, the control unit 200 controls the raw material gas supply device 112, the carrier gas supply device 114, and the combustion gas supply device 116 to stop the gas supply. In addition, the control unit 200 controls the spindle mechanism 102 to stop the rotation of the target rod 104.

[0055] Then, the control unit 200 drives the target rod 104 via the spindle mechanism 102 to unload the optical fiber preform 10 with the glass soot deposited on the surface of the target rod 104 from the reaction vessel 101 (step S108), thereby completing the process.

[0056] As described above, according to the manufacturing apparatus 100 for the optical fiber preform 10 of this embodiment, the heat shielding curtain 111 moves integrally with the burner 106. This makes it possible to suppress deterioration and alteration of the heat shielding object T caused by the radiant heat from the burner 106, thereby reducing the risk of breakdowns and dust generation. Furthermore, if the heat shielding object T is an electronic component of a control system, malfunction of the control system caused by heat can also be suppressed.

[0057] According to the manufacturing apparatus 100 for the optical fiber preform 10 of this embodiment, various heat-shielding objects T (pipes, driving parts, control cables, etc.) are arranged on the opposite side of the heat-shielding curtain 111 from the burner 106 and the target rod 104 (optical fiber preform) heated by the burner 106. This makes it possible to further suppress deterioration and degeneration of the heat-shielding objects T due to radiant heat from the burner 106.

[0058] Fig. 7 is a perspective view for explaining the internal structure of a manufacturing apparatus that is a comparative example of the manufacturing apparatus 100 for the optical fiber preform 10 according to the present embodiment. Unlike the manufacturing apparatus 100, the apparatus shown in Fig. 7 has an opening OP (gap) for the burner 106 to move between two separate heat shielding curtains 111. In this case, even if the heat shielding curtain 111 is provided near the burner 106, the radiant heat from the burner 106 is transmitted to the heat shielding object T through the opening OP.

[0059] In contrast, according to the manufacturing apparatus 100 for the optical fiber preform 10 according to the present embodiment, the heat shielding curtain 111 is provided on the side facing the target rod 104 such that the burner 106 fits into a through hole 111a formed in the heat shielding curtain 111. The outlet of the burner 106 protrudes toward the target rod 104. The heat shielding curtain 111 extends without any gaps around the outlet of the burner 106. Since the heat shielding curtain 111 is present in the vicinity of the burner 106 which is most susceptible to the effect of radiant heat, the radiant heat from the burner 106 can be shielded more reliably than in the case of an apparatus structure such as the comparative example.

[0060] [Second embodiment] The optical fiber preform manufacturing apparatus 300 according to the second embodiment of the present invention will be described with reference to Fig. 8. Fig. 8 is a schematic diagram illustrating a structure for applying tension to the heat shielding curtain 111 in the optical fiber preform manufacturing apparatus 300 according to this embodiment. Note that the same components as those in the optical fiber preform manufacturing apparatus 100 according to the first embodiment described above are denoted by the same reference numerals, and descriptions thereof will be omitted or simplified.

[0061] The basic configuration of the manufacturing apparatus 300 for the optical fiber preform 10 according to this embodiment is substantially the same as the configuration of the manufacturing apparatus 100 according to the first embodiment. The manufacturing apparatus 300 differs from the manufacturing apparatus 100 in the members constituting the tension application mechanism.

[0062] As shown in FIG. 8, in the manufacturing apparatus 300, a spring 119 is provided on a part of the surface of the thermal insulation curtain 111 opposite to the surface on which the burner 106, which is a heat source, is provided and located below the pair of rollers 109a, 109b. The spring 119 connects one end and the other end of the rectangular thermal insulation curtain 111, and is an elastic member that expands and contracts along the longitudinal direction L. The thermal insulation curtain 111 is formed into a ring shape by connecting both ends via the spring 119. When the thermal insulation curtain 111 is hung over the pair of rollers 109a, 109b, the spring 119 elastically deforms so that one end moves in the direction of the arrow J and the other end moves in the direction of the arrow K. This allows the spring 119 to apply tension to the thermal insulation curtain 111.

[0063] As described above, in the manufacturing apparatus 300 according to this embodiment, tension is applied to the heat shielding curtain 111 from the spring 119. In other words, tension can be applied to the heat shielding curtain 111 with a structure simpler than that of the first embodiment, without driving the pair of rollers 109a, 109b. In addition, by utilizing the expansion and contraction of the spring 119 when hanging the heat shielding curtain 111 over the pair of rollers 109a, 109b or when removing it, the heat shielding curtain 111 can be easily attached and removed.

[0064] Moreover, according to the manufacturing apparatus 300 of this embodiment, the roller position moving mechanism 110 can be omitted, which has the advantage of further reducing manufacturing costs.

[0065] [Third embodiment] An apparatus 400 for manufacturing an optical fiber preform 10 according to a third embodiment of the present invention will be described with reference to Fig. 9. Fig. 9 is a schematic diagram showing the overall configuration of the apparatus 400 for manufacturing an optical fiber preform 10 according to this embodiment. Note that the same components as those in the apparatus for manufacturing an optical fiber preform according to the above-mentioned first embodiment are given the same reference numerals, and descriptions thereof will be omitted or simplified.

[0066] The basic configuration of the manufacturing apparatus 400 for the optical fiber preform 10 according to this embodiment is almost the same as that of the first embodiment. The manufacturing apparatus 400 is different from the manufacturing apparatus 100 in that the manufacturing apparatus 400 further includes rollers 109c and 109d in addition to the pair of rollers 109a and 109b.

[0067] 9, rollers 109c and 109d are disposed spaced apart from rollers 109a and 109b in the vertical direction (up and down direction in the figure). Heat shielding curtain 111 is hung across the four rollers 109a to 109d.

[0068] As described above, in the manufacturing apparatus 400 according to this embodiment, the heat shielding curtain 111 is hung between the four rollers 109a to 109d, so that a larger space than that of the first embodiment is formed inside the heat shielding curtain 111. As a result, when the object T to be heat shielded is placed in the internal space, it is possible to achieve an effect that the object T is less susceptible to the influence of radiant heat than in the first embodiment.

[0069] It should be noted that the above-described embodiments are merely illustrative examples of the implementation of the present invention, and the technical scope of the present invention should not be construed as being limited thereby. In other words, the present invention can be implemented in various forms without departing from its technical concept or main features.

[0070] [Modified embodiment] In the above-described embodiment, the number of rollers over which the heat shielding curtain 111 is hung is two or four, but the number of rollers is not limited to these. For example, the number of rollers may be at least two, and may be three or more.

[0071] In the above-described embodiment, the heat shielding object T, which is shielded from radiant heat from the burner 106, is disposed in the space inside the heat shielding curtain 111. However, the position where the heat shielding object T is disposed does not have to be the space inside the heat shielding curtain 111. The heat shielding object T only needs to be disposed on the opposite side of the heat shielding curtain 111 to the target rod 104. For example, the heat shielding object T may be disposed below the bottom surface of the heat shielding curtain 111 in the vertical direction.

[0072] In the above-described second embodiment, the spring 119 is used as an example of the tension applying mechanism, but other elastic members may be used. For example, instead of the spring 119, an elastic member made of resin may be used. [Explanation of symbols]

[0073] 10. Optical fiber base material 100,300,400...manufacturing equipment 101... Reaction vessel 102 Spindle mechanism 103···Chuck 104 Target Rod 105···Dummy rod 106 Burner 107···Guide rail 108···Traverse motor 109a, 109b, 109c, 109d... Roller 110... Roller position moving mechanism 111...Heat-blocking curtains 111a...Through hole 112 Raw material gas supply device 113 Raw gas supply line 114 Carrier gas supply device 115 Carrier gas supply line 116 Combustion gas supply device 117 Combustion gas supply line 118...Exhaust mechanism 119 Spring 200...Control section 201···CPU 202...ROM 203...RAM 204...Non-volatile memory 205 Input operation section 206...Display section 207a~207h Drive circuit

Claims

1. a burner unit for blowing a flame containing glass soot generated from a raw material gas of the optical fiber preform onto a rod-shaped starting substrate; A moving mechanism that moves the burner unit along the longitudinal direction of the starting substrate; A band-shaped heat shield member that moves integrally with the burner portion; A plurality of rollers around which the heat shield is stretched; a tension applying mechanism that applies tension to the heat insulating member; Equipped with The tension applying mechanism drives at least one of the plurality of rollers to adjust the distance between the rollers.

2. An optical fiber preform manufacturing apparatus comprising:

2. the heat insulating member is subjected to a pushing force from one end of the burner portion in the longitudinal direction in association with the movement of the burner portion, and is also subjected to a pulling force from the other end of the burner portion in the same direction as the pushing force.

2. The apparatus for manufacturing an optical fiber preform according to claim 1.

3. The burner portion is fitted into a through hole formed in the heat insulating member.

3. The apparatus for manufacturing an optical fiber preform according to claim 1 or 2.

4. The tension applying mechanism is an elastic member that is provided in a part of the heat insulating member and expands and contracts along the longitudinal direction.

2. The apparatus for manufacturing an optical fiber preform according to claim 1.

5. The plurality of rollers is provided in three or more numbers.

5. The apparatus for manufacturing an optical fiber preform according to claim 1,

6. The object to be heat-insulated from the radiant heat from the burner unit is disposed on the opposite side of the heat-insulating member from the starting substrate.

6. The apparatus for manufacturing an optical fiber preform according to claim 1,

7. The object is disposed inside the ring-shaped heat shield.

7. The apparatus for manufacturing an optical fiber preform according to claim 6.

8. A step of blowing a flame containing glass soot generated from a raw material gas of an optical fiber preform from a burner unit onto a rod-shaped starting substrate; Moving the burner unit along a longitudinal direction of the starting substrate; Equipped with A strip-shaped heat shielding member is stretched across a plurality of rollers and moves together with the burner unit. A tension applying mechanism applies tension to the heat insulating member, The tension applying mechanism drives at least one of the plurality of rollers to adjust the distance between the rollers.

2. A method for manufacturing an optical fiber preform comprising the steps of:

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