JP2005148170A - Heat-treatment device and heat treatment of optical fiber reinforcing member and optical fiber fusion splicing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat-treatment device and a heat treatment capable of performing heating with uniform temperature in which temperature difference on exothermic parts of a planar heating element is small in the heat-treatment of the optical fiber reinforcing member using a planar heating element. <P>SOLUTION: This heat-treatment device or the heat treatment of the optical fiber reinforcing member is a heat-treatment device or a heat treatment which performs heating contraction of the optical fiber reinforcing member 12 for protecting the fusion splicing part of an optical fiber 11 and it is constituted so that a heating part is formed with a planar heating element 13 which is curved in U-shape and a soaking plate 25 made of a metallic sheet is joined to the exothermic part 13b of the planar heating element. Moreover, the soaking plate 25 is joined at the side of the inner surface side of the planar heating element 13 which is curved in the U shape and further fluorinated carbon resin is coated on the surface of the soaking plate 25. Furthermore, the soaking plate 25 may be formed with a plurality of soaking plates which are thermally separated to the axial direction of the optical fiber reinforcing member 12. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a heat treatment apparatus and a heat treatment method for an optical fiber reinforcing member that covers and reinforces an optical fiber fusion spliced portion with a sleeve-shaped protective member and heat shrinks the optical fiber fusion splicing apparatus.

  Conventionally, fusion splicing of optical fibers is performed by removing the fiber coating at the connection end and heating and melting the exposed butted end portion of the bare glass portion of the glass. The bare fiber part, from which the fiber coating has been removed and fusion-spliced, is protected by a reinforcing member because of its low mechanical strength. This reinforcing member is usually configured by attaching a strength member (also called a reinforcing bar) in a heat-shrinkable tube that shrinks in the radial direction by heating and housing a heat-melting tube made of a heat-melting adhesive resin. (For example, refer to Patent Document 1).

  FIG. 7 is a diagram showing a conventional heat treatment method for a fusion splicing part disclosed in Patent Document 1, and FIG. 7A is a diagram for explaining an example of a general reinforcing member, and FIG. FIG. 7 is a diagram showing an example of heat treatment using a V-groove heater base, and FIG. 7C is a diagram showing an example of heat treatment using a U-groove heater base. In the figure, 1 is a single-core optical fiber, 1 'is a tape-shaped optical fiber, 2 is a fusion splicing part, 3 is a heat-shrinkable tube, 4 is a heat-meltable tube, and 5 and 5' are Strength members, 6 and 6 'are reinforcing members, 7 is a V-groove heating surface, 8 is a U-groove heating surface, and 9 and 9' are heater stands.

  In the example of the single-core optical fiber shown in FIG. 7A, both the optical fiber cores 1 that are fusion-spliced to each other remove the fiber coating at the connection end, expose the bare fiber portion, and butt the ends. Are fused and connected by arc discharge or the like. The reinforcing member 6 has a length that covers a predetermined range of the fiber coating on both sides of the bare fiber portion, and in the heat-shrinkable tube 3, a heat-meltable tube 4 made of a heat-meltable adhesive and a half-moon-shaped tensile body. 5 is configured. The spliced optical fiber core wire 1 is inserted into the heat-meltable tube 4 so that the fusion splicing portion 2 is located at the center, and is heated by a flat heater base 9.

  FIGS. 7B and 7C show examples in which the fusion spliced portion of the multi-fiber ribbon optical fiber core wire 1 ′ is reinforced. Also in this case, the reinforcing member 6 'is configured by housing the heat-meltable tube 4 made of a heat-meltable adhesive and the tensile body 5' in the heat-shrinkable tube 3 as in FIG. 7A. The Further, optical fiber cores 1 ′ are arranged on both sides of the strength member 5 ′ to collectively reinforce a plurality of fusion splicing portions. The heater base 9 ′ has a V-shaped groove 7 having a V-shaped cross section as shown in FIG. 7B or a U-shaped cross section as shown in FIG. 7C. It is formed of a U-groove 8 having In addition, also in the single-core optical fiber core wire 1 of FIG. 7 (A), the heater stand 9 'of the V-groove 7 or the U-groove 8 can be used.

The reinforcing member 6 ′ is heated by heat from the concave wall surface formed by the V-groove 7 or the U-groove 8, and the heat-shrinkable tube 3 is thermally contracted to reduce the void volume in the tube. At the same time, the heat-meltable tube 4 is melted to fill the voids in the heat-shrinkable tube 3 and surround the exposed fusion splicing portion and its peripheral portion. Thereafter, the melted heat-meltable tube 4 is solidified, and the heat-shrinkable tube 3, the strength member 5 ′, and the optical fiber core wire 1 ′ including the fusion splicing portion are integrated to complete reinforcement. When the reinforcing member 6 ′ is heated, the heating surface of the heater base 9 ′ is formed as a concave wall surface formed of the V-groove 7 or the U-groove 8 as shown in FIGS. 7B and 7C. It is said that uniform and efficient heating can be performed as compared with the case of heating with a heater base 9 having a flat heating surface as shown in FIG.
JP-A-9-297243 (refer to FIGS. 4 and 6 and the description thereof)

  However, the fusion splicing of the optical fiber cores varies from a single optical fiber core to a multi-fiber ribbon optical fiber. Accordingly, the thickness of the reinforcing member is different. For example, when the cross-sectional diameter of the reinforcing member before contraction is about 4 mm for a single-core optical fiber, The cross-sectional diameter is about 8 mm. For this reason, it is necessary to prepare and prepare heaters having various sizes of heating recesses, which are generally made of metal, ceramic, etc., and there are problems in cost and management.

  On the other hand, an example is also known in which a flexible sheet heating element is bent into a U shape to form a heater and used for heat treatment of a reinforcing member. By using this flexible planar heating element, it is possible to deal with reinforcing members having different thicknesses, and the heater configuration is relatively simple and useful. However, this planar heating element is usually in the form of a heating element bonded to the surface of an organic resin film, and the heat capacity per unit area is relatively small. For this reason, in the heat generating part of the planar heating element, if there are a part that contacts the reinforcing member and a part that does not contact the reinforcing member, the part that contacts the reinforcing member becomes constant at a relatively low temperature due to the heat transfer action, Since there is no heat dissipation due to heat transfer at the portion not in contact with the reinforcing member, there is a risk of burning at a temperature higher than the heat-resistant temperature.

  The present invention has been made in view of the above-described circumstances, and heating is performed at a uniform temperature with a small temperature difference in the heat generation portion of the planar heating element by heat treatment of the optical fiber reinforcing member using the planar heating element. It is an object of the present invention to provide a heat treatment apparatus and a heat treatment method that can perform heat treatment.

  A heat treatment apparatus or a heat treatment method for an optical fiber reinforcing member according to the present invention is a heat treatment apparatus or a heat treatment method for heat-shrinking an optical fiber reinforcing member that protects a fusion spliced portion of an optical fiber, wherein the heating unit is U It is formed of a sheet heating element curved in a letter shape, and a heat equalizing plate made of a metal plate is joined to the heat generating portion of the sheet heating element. The soaking plate is joined to the inner surface side curved in a U shape, and the soaking plate surface is coated with a fluororesin. Furthermore, the soaking plate may be formed of a plurality of soaking plates that are thermally separated with respect to the axial direction of the reinforcing member.

  The heat equalizing plate joined to the heat generating part of the planar heating element reduces the temperature difference between the part where the optical fiber reinforcing member contacts and the part where the optical fiber reinforcing member does not contact, and suppresses the temperature rise of the part where the optical fiber reinforcing member does not contact. It is possible to prevent the sheet heating element from burning out. In addition, by coating the surface of the soaking plate with a fluororesin, it can be easily wiped even if the hot-melt tube melts and adheres to the heating element.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a view showing an example of a heat treatment apparatus for explaining the outline of the present invention, and FIG. 2 is a view showing a sectional structure with a part of FIG. 1 removed. In the figure, 10 is a heat treatment apparatus, 11 is an optical fiber core, 12 is a reinforcing member, 13 is a planar heating element, 13a is a non-heating part, 13b is a heating part, 14 is a base part, and 15 is a heating element support part. , 15a is a support frame, 16 is a clamp base part, 16a is a groove part, 17 is a clamp part piece, 18 is a handle part, 19 is a grip pad, 20 is a pressing member, 21 is a cover, and 22 is a circuit board.

  The heat treatment apparatus 10 accommodates a fusion splicing portion of a single-core or multi-fiber ribbon optical fiber core wire 11 and a planar heating element 13 for heating a reinforcing member 12 arranged to protect the vicinity thereof. Constructed with support. In the same manner as shown in FIG. 7, the reinforcing member 12 is a heat-shrinkable tube made of hot-melt adhesive resin and a tensile body (also called a reinforcing bar) formed of stainless steel, glass, ceramic, or the like. ). Although details of the planar heating element 13 will be described later, the heating element 13 has a structure in which a heating element (for example, a resistance wire is pasted) is joined to a heat-resistant polyimide film or the like, and has flexibility capable of bending. Things are used.

  The main body of the heat treatment apparatus 10 includes a heating element support 15 for supporting the planar heating element 13 on the base 14, and a clamp base 16 that holds the optical fiber core wire 11 on both sides of the base 14. It has. The heating element support portion 15 is composed of a pair of support frames 15a (see FIG. 2) parallel to each other, and the non-heating portions 13a on both sides of the planar heating element 13 curved in a U shape are mounted on the support frame. It is attached by pressing with a pressing member 20 having an L-shaped cross section from above. The heating portion 13b of the planar heating element 13 curved in a U shape is positioned between the pair of support frames 15a, and the reinforcing member 12 is housed and placed inside the U shape. The optical fiber core wire 11 extending from both ends of the reinforcing member 12 is drawn out from the groove portion 16 a of the clamp base portion 16.

  The clamp base part 16 is provided with a clamp part piece 17 so as to be rotatable, and is operated by gripping the handle part 18. A gripping pad 19 using an elastic body that can securely grip the optical fiber core wire 11 and does not damage the optical fiber core wire 11 is provided at a portion that grips the optical fiber core wire 11. Moreover, the clamp part piece 17 can be set as the structure fixed by adsorption | suction using a magnet. When the clamp piece 17 is closed, the optical fiber core wire 11 is preferably gripped so as to be substantially linear including the fusion splicing portion. In this case, although the thickness of the reinforcing member 12 varies depending on the number of fiber cores, the supporting height of the reinforcing member 12 can be adjusted by adjusting the pressing position of the heating element support portion 15. Further, a configuration (not shown) for applying a constant tension to the optical fiber core 11 may be added until the clamp portion 17 is closed and the support of the optical fiber core 11 is fixed.

  A cover 21 is provided on the upper surface side of the base portion 14 so as to be openable and closable so that the heating portion is not touched by the hand during the heat treatment or the heating state is not affected by the ambient air. Further, the cover 21 is formed of a transparent resin, and the contraction state of the heat-shrinkable tube of the reinforcing member 12 and the melted state of the heat-meltable tube can be monitored. A space is provided on the lower surface side of the base portion 14, and a control circuit board 22 and the like are mounted thereon.

  FIG. 3 is a view for explaining the outline of the heating method of the reinforcing member according to the present invention. 4A and 4B are diagrams showing a specific example of the planar heating element according to the present invention. FIG. 4A is a plan view of the planar heating element in an uncurved state, and FIG. 4B is aa of the planar heating element. FIG. 4C is a partial cross-sectional view illustrating a state where the planar heating element is bent in a U shape. In the figure, 23 is a heating element, 24a and 24b are insulating films, 25 is a soaking plate, 26 is an auxiliary plate, 27 is a lead terminal, 28 is solder, and 29 is a sealing resin. Description of other reference numerals is omitted by using the same reference numerals as those used in FIGS.

  As shown in FIG. 3, the planar heating element 13 is curved so that the cross section of the surface orthogonal to the axial direction of the reinforcing member 12 is U-shaped, and the U-shaped state is maintained. As shown by 2, the non-heat generating portions 13 a on both sides are fixed by the heating element support portion and the pressing member. The reinforcing member 12 is housed and placed in the U-shaped heat generating portion 13b at the center together with the optical fiber core wire 11 that is fused and connected. At this time, the reinforcing member 12 is in contact with the U-shaped curved bottom, but the side surface is in a non-contact state. In the initial state where the reinforcing member 12 is not yet heated and shrunk, the contact area of the non-contact portion is relatively large. However, when the outer diameter of the reinforcing member 12 is reduced due to heating, the area of the contact portion is reduced. And the area of the non-contact portion increases.

  In the present invention, a soaking plate 25 made of a flexible metal plate having a good thermal conductivity such as aluminum or copper is joined by bonding or the like so as to cover almost the entire region of the heat generating portion 13b. The soaking plate 25 is preferably provided on the inner side curved in a U shape, and the reinforcing member 12 is housed and placed so as to be in direct contact with the soaking plate 25. The reinforcing member 12 is heated by heat conduction from the U-shaped bottom through the heat equalizing plate 25 and heated by heat radiation from the side. By this heating, the heat-shrinkable tube can be thermally shrunk to reduce the void volume in the tube, and the heat-meltable tube can be melted to fill the reduced void volume.

Here, in the configuration that does not include the soaking plate 25, heat from the heat generating portion 13b is radiated to the reinforcing member 12 by heat conduction at the contact portion with the reinforcing member 12, but only heat radiation by radiation at the non-contact portion. Much less than heat dissipation due to heat conduction. For this reason, a temperature difference occurs between the non-contact portion and the contact portion of the reinforcing member 12, and the temperature of the planar heating element 13 may be increased to a temperature higher than the heat-resistant temperature at the non-contact portion. .
However, by providing the heat equalizing plate 25 as in the present invention, the temperature difference between the non-contact portion and the contact portion of the reinforcing member 12 can be reduced, and as a result, the temperature of the entire heat generating portion 13b is made uniform. Further, it is possible to prevent the planar heating element 13 from being damaged.

  Further, the heating of the reinforcing member 12 may cause the hot-melt tube made of hot-melt adhesive resin to melt and sag outside. In this case, it may be difficult to remove the adhesive adhered to the surface of the sheet heating element 13. For this reason, in this invention, it can be set as the structure which gave the coating of the fluororesin to the surface of the soaking | uniform-heating board 25. FIG. By providing a film of fluororesin, for example, even if a molten adhesive adheres, it can be easily removed and workability can be improved.

  A specific example of the planar heating element 13 will be described with reference to FIG. 4. As shown in FIG. 4A, the planar heating element 13 in a flat state that is not curved is heated by the heating element 23 in the central main region. It has the part 13b, and has the non-heating part 13a which does not have a heat generating element in the both sides. The planar heating element 13 is formed in, for example, a rectangular shape having a lateral width of about 36 mm and an axial width of about 70 mm in a flat state, and the heating portion 13b having a lateral width of about 20 mm. The heating element 23 is formed by, for example, cutting a stainless thin plate having a thickness of about 32 μm into a zigzag shape. This is sandwiched between insulating films 24a and 24b made of a heat-resistant polyimide film having a thickness of, for example, about 25 μm to form a flexible planar heating element. Further, as shown in FIG. 4B, lead terminals 27 are connected to both ends of the heat generating element 23 by solder 28. This connecting portion is protected by a heat resistant sealing resin 29.

  For example, an aluminum plate having a thickness of about 0.2 mm is bonded as a soaking plate 25 by bonding or the like so as to cover the entire heating portion 13b where the heating element 23 exists. The soaking plate 25 may be bonded to both sides of the insulating films 24a and 24b, but may be only one. However, when it is provided only on one side, it is preferably joined to the inner surface side curved in a U-shape. In addition, auxiliary plates 26 may be joined to the non-heat generating portions 13a on both sides of the planar heating element 13 in order to facilitate installation and handling on the heating element support. The auxiliary plate 26 is independent of the soaking plate 25 and may be joined to both sides of the insulating films 24a and 24b, but may be only one or the same metal as the soaking plate 25. Although it may be formed of a plate, it may be different.

  The planar heating element 13 is curved from a flat plate shape to a U-shape as shown in FIG. 4C, and as explained in FIG. 3, the non-heating part 13a on both sides is held by the heating element support portion, It is set as the shape which can be accommodated and mounted so that a reinforcing member may be wrapped in the center U-shaped heat-emitting part 13b. A terminal 27 for supplying heating power to the heating element 23 is connected to the circuit board 22 shown in FIG. Further, by providing a temperature detection element (not shown) such as a thermistor in the vicinity of the heat generating element 23, the heating temperature can be automatically controlled.

  FIG. 5 is a diagram showing another specific example of the planar heating element. In the example of FIG. 4, the planar heating element 13 ′ uses a single heat equalizing plate 25 that covers the entire heating portion 13 b, whereas the planar heating element 13 ′ is divided into a plurality of parts in the axial direction, Specifically, this is an example of using a separated soaking plate 25 '. As described with reference to FIG. 3, the contact portion and the non-contact portion of the reinforcing member 12 in the heat generating portion 13 b are generated in the side surface direction perpendicular to the axial direction of the reinforcing member 12. Therefore, it is only necessary to equalize the temperature in the width direction that is the side surface direction of the sheet heating element 13 ′, and it may be advantageous to provide a temperature difference between the central portion and both end portions in the axial direction of the reinforcing member. .

  FIG. 5B is an example in which the heating temperature at the central portion side of the reinforcing member 12 is increased and the heating temperature is decreased as it goes to both end portions. The temperature pattern as shown in the figure can be easily realized by increasing the formation density of the heating elements 23 on the center side. However, since the heat radiation at both end portions is usually large, the heating temperature at the central portion side is somewhat higher even when the density of the heat generating elements 23 is formed uniformly. By increasing the heating temperature on the center side, the reinforcing member 12 starts to heat shrink from the center side, and the heat shrinkable tube sequentially shrinks toward both end sides. In addition, since the internal heat-meltable tube starts to melt from the center side and the adhesive is sequentially pushed out toward the both end sides, it is difficult for bubbles to remain in the reinforcing member. For this reason, generation | occurrence | production of the side pressure with respect to the optical fiber by a bubble, etc. are reduced.

  As shown in FIG. 5A, the sheet heating element 13 is formed by joining the heat equalizing plates 25 ′ that are thermally separated in the axial direction of the reinforcing member 12 and divided into a plurality of parts. 'Is soaked in the lateral direction in which the contact portion and the non-contact portion of the reinforcing member 12 are generated, but a temperature difference can be given to the axial direction. Therefore, it is possible to perform the heat treatment with the temperature pattern as shown in FIG. 5B while simultaneously preventing the planar heating element from being burned by using the soaking plate.

  FIG. 6 is a diagram showing a configuration example in which the heat treatment apparatus according to the present invention is mounted on the fusion splicing apparatus. In the figure, 30 is a fusion splicing device, 31 is a monitor device, 32 is a fusion mechanism portion, and 33 is a clamp portion. Description of other reference numerals is omitted by using the reference numerals used in FIGS. As the fusion mechanism part 32 (detailed configuration is omitted), various structures that can perform single-core fusion connection using arc discharge, multi-core batch fusion connection, or the like can be used. In the present invention, the heat treatment device 10 described above is installed in parallel with the fusion mechanism portion 32 of the fusion splicing device 30, thereby improving workability.

  When the single-core or multi-fiber optical fiber 11 is installed in the fusion mechanism 32, the reinforcing member 12 is passed through one of the optical fiber cores 11 in advance. The optical fiber core wire 11 is held and aligned by the clamp portion 33, and the optical fiber connection end is aligned by an aligning means (not shown) to perform the fusion connection. Each processing state of the fusion splicing is sequentially displayed by the monitor device 31. Thereafter, the optical fiber core wire 11 is removed from the clamp portion 33, and the reinforcing member 12 is moved to the fusion splicing portion. Next, the reinforcing member 12 is housed and placed in the U-shaped planar heating element 13 of the heat treatment apparatus 10 installed adjacently while maintaining the state, and the optical fiber core wire 11 is clamped by the clamp bases 16 on both sides. Is held and fixed, and heat treatment is performed under predetermined control.

It is a figure explaining the outline of the heat processing apparatus of the optical fiber reinforcement member by this invention. It is a figure which shows the cross-section of the heat processing apparatus which removed a part of FIG. It is a figure explaining the outline of the heating method of the reinforcement member by this invention. It is a figure which shows the specific example of the planar heating element by this invention. It is a figure which shows the other specific example of the planar heating element by this invention. It is a figure which shows the structural example which mounts the heat processing apparatus by this invention in the fusion splicing apparatus. It is a figure explaining the heat processing method of the conventional optical fiber reinforcement member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Heat processing apparatus, 11 ... Optical fiber core wire, 12 ... Reinforcing member, 13, 13 '... Planar heating element, 13a ... Non-heating part, 13b ... Heating part, 14 ... Base part, 15 ... Heating element support part 15a ... support frame, 16 ... clamp base, 16a ... groove, 17 ... clamp part piece, 18 ... grip part, 19 ... grip pad, 20 ... holding member, 21 ... cover, 22 ... circuit board, 23 ... heating element 24a, 24b ... insulating films, 25, 25 '... soaking plate, 26 ... auxiliary plate, 27 ... lead terminal, 28 ... solder, 29 ... sealing resin, 30 ... fusion splicing device, 31 ... monitor device, 32 ... Fusion mechanism part, 33 ... Clamp part.

Claims (6)

  A heat treatment apparatus for heating and shrinking an optical fiber reinforcing member that protects a fusion spliced portion of an optical fiber, wherein the heating portion is formed of a planar heating element curved in a U shape, and the heating of the planar heating element A heat treatment apparatus for an optical fiber reinforcing member, characterized in that a soaking plate made of a metal plate is joined to the portion.   The heat treatment apparatus for an optical fiber reinforcing member according to claim 1, wherein the heat equalizing plate is joined to an inner surface side of the U-shaped curved heating element.   The heat treatment apparatus for an optical fiber reinforcing member according to claim 2, wherein a surface of the soaking plate is coated with a fluororesin.   The optical fiber according to any one of claims 1 to 3, wherein the heat equalizing plate is formed of a plurality of heat equalizing plates that are thermally separated in the axial direction of the reinforcing member. Heat treatment apparatus for reinforcing members.   A heat treatment method for heating and shrinking an optical fiber reinforcing member that protects a fusion spliced portion of an optical fiber, wherein the optical fiber reinforcing member is curved in a U shape and has a heat-generating portion made of a metal plate. A heat treatment method for an optical fiber reinforcing member, wherein the heat treatment method is carried out by being stored and mounted on a planar heating element joined with a plate.   An optical fiber fusion splicer comprising the optical fiber reinforcing member heat treatment apparatus according to any one of claims 1 to 4.

Images