KR20050088709A - Structure of air blown optical fiber & manufacturing method and apparatus thereof - Google Patents

Abstract

The present invention relates to a structure of an optical blower fiber (ABF) or an optical blower cable (ABC) used in air blown installation, and a manufacturing method and apparatus associated therewith. Silver is a polymer material protruding on the outer surface is solidified by spraying an oligomer (Oligomer) having a predetermined molecular weight or more in a photocuring or thermal curing method. The polymer material may or may not be the same material as the outer coating material, and the shape may be hemispherical, spherical, deformed hemispherical, deformed spherical, and on the surface, convexly convex, the optical fiber is easily placed under the resistance of air pressure.

Since the optical fiber unit and cable for pneumatic installation according to the present invention do not use particles like the conventional pneumatic fiber optical unit, cracking of the interface between the bead and the polymer occurs due to bending, or the optical fiber unit is cracked. Not only does not propagate to the inside of the glass, but also because the high elastic material can be used in the conventional glass or ceramic beads (Bead) does not damage the glass beads in the optical fiber unit for pneumatic laying. Countless beads are formed and hardened by spraying a low-cost photocurable polymer with a spray gun on top of the coating material, which makes it possible to form protrusions. Therefore, it is unnecessary to handle beads that are harmful to the human body. There is no problem in handling and the installation characteristics of the optical fiber unit are increased.

Description

Structure of Air Blown Optical Fiber and its Manufacturing Method and Apparatus {Structure of Air Blown Optical Fiber & Manufacturing Method and apparatus}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber for pneumatic laying, and more particularly, to an optical fiber capable of maximizing fluid traction in air blowing (Air Blown Fiber) and an optical fiber cable (Air Blown Cable). It relates to a structure and a method and apparatus for manufacturing the same.

In general, optical fiber has long been used as a long-distance high speed transmission medium because of low transmission loss and high bandwidth. The optical fiber itself is very weak to external impact or bending. Therefore, the optical fiber usually needs to be laid such that it is coated on a fiber and coated with a polymer material on the outside.

Conventional optical fiber laying processes include a method of laying an optical fiber in bundles or twisting them into a cable state and then laying the fiber in a cable state, and a method of laying an optical cable using air pressure.

Recently, as the communication systems that can cope with new communication environments and capacities are diversified, the types of optical fibers are diversified. Therefore, it is not desirable to bury a large amount of a specific optical fiber now without considering the future environment. Moreover, in situations where the type of fiber or fiber in the future cannot be determined at the access network or premise wiring side, it is economically undesirable to lay large quantities of specific fiber cables at high cost.

Attempts to install fiber-optic cables, such as fiber-optic units, that collect several fiber strands in tight spaces using pneumatic pressure, were first proposed by British Telecom (US 4,961,896) in 1980.

An air blown fiber (hereinafter referred to as 'ABF') is prepared by first preparing a tube made of a polymer material called a micro tube or duct having a special composition and cross-sectional shape, and then using a specific optical fiber using air pressure. It is prepared by blowing as needed. The Air Blown Cable (hereinafter referred to as 'ABC') differs in that ABF uses up to 12 optical fibers but aggregates about 30 to 50 optical fibers, but the laying principle is the same as ABF. Hereinafter, ABF refers to ABC together)

ABF is not only easy to install but also easy to remove, small in size and flexible, which not only reduces initial installation cost but also reduces the burden on additional installation and makes it easier to supplement performance in the future. Especially, FTTH (Fiber to the It is suitable for indoor such as Home.

Since the ABF provides only the tubes required for laying, it is almost unrestricted even if there is no room for manufacturing.

The general process involved in laying ABF is as follows:

First, a dedicated tube for pneumatic laying is prepared and installed in advance in the required section, and the necessary optical fiber unit (ABF) is blown into the tube by using a pneumatic laying head (Blowing head). Since this laying process utilizes the fluid drag force of the fluid, the optical fiber unit preferably has a structure and a material whose outer surface can maximize the fluid traction force. The structure and the material of the outer surface of the optical fiber unit determine the laying characteristics such as the laying distance and the minimum installation radius in pneumatic laying.

There are various types of ABF structures for increasing the flow traction of the fluid, the representative of which are US Patent Nos. 5,042,907, 5,533,164, 5,555,335, 4,440,053, 6,341,188, etc. This is about improving the surface.

U.S. Patent No. 5,042,907 proposed a method of uniformly applying pre-stirred hollow glass beads to a coating resin on the outer surface of the ABF in order to allow the ABF to be placed to receive more air pressure. However, the glass beads in the resin are relatively larger than the thickness of the coating layer on the outer surface of the ABF, and the bending characteristics of the optical fiber unit are not good because of the high Young's Modulus characteristic for obtaining high propulsion force. There is a problem that cracks are generated between them and propagate inside the optical fiber. A method for solving the above problems has been disclosed by providing an intermediate layer between the inner buffer layer and the outer surface of the ABF. However, the process has to be complicated because it must be repeated three or more times.

U.S. Patent No. 5,555,335 is a method in which the glass beads are coated on the optical fiber without pre-stirring the glass beads, and then the glass beads are blown to the outer skin layer by an electrostatic method before curing. However, this method has been found to be difficult to apply to the actual process due to the nonuniformity of the adhesion strength distribution of the glass beads adhering to the surface of the ABF, as well as the disadvantage that some glass beads may fall off or be sucked in operation.

Unlike the method using beads, U. S. Patent No. 5,441, 813 is a method of forming a concave shape (Dimple) using a foamable polymer material on the surface of the ABF. However, when the foamable polymer material is used, there is a problem in that the installation distance is shortened because of the high coefficient of friction, and the strength of the optical fiber unit is reduced, thereby additionally coating a high strength polymer layer therein.

Another conventional method is a method of winding a fiber of a special material on a ribbon optical fiber. However, since the ribbon-type optical fiber has a strong direction against bending, it has a disadvantage in that the installation property is very weak, such as bending only in one direction.

The present invention has been conceived to solve the above problems, in the structure of the optical fiber unit and cable laid using air pressure, the outer surface of the optical fiber unit to suppress the occurrence of bending cracks caused by the particle-containing sheath applied to the prior art Pneumatically laid optical fiber that maximizes the fluid drag force and improves the installation characteristics by providing a polymer protrusion (polymer bead) in the coating layer by coating to form a circular cross section so as to have a low directionality during installation. The purpose is to provide a structure.

Another object of the present invention is to provide a method and apparatus for manufacturing an optical fiber for pneumatically laid structure, which can be easily manufactured by applying a simpler process than the existing method, and the cost can be greatly reduced.

In the pneumatic laying optical fiber structure according to the present invention for achieving the above object, the pneumatic laying optical fiber structure is formed inside the tube using the air pressure, and includes an outer skin layer provided on the outside of at least one optical fiber, the outer layer of the outer skin layer It has a polymer bead layer of a predetermined shape provided on the surface.

Preferably, the polymer bead layer is convexly photocured or thermoset after spherically spraying an oligomeric polymer onto the surface of the skin layer.

Preferably, the optical fiber is a single or multimode optical fiber.

Preferably, the optical fiber structure according to the present invention further includes at least one of a protective layer and a paint layer provided inside the outer layer.

Preferably, the mineral oil structure according to the present invention further includes at least one fiber or wire having a higher tensile strength than the optical fiber.

Preferably, the tensile strength reinforcing fiber is Kevlar or FRP.

Preferably, the optical fiber is in the form of an independent single core or ribbon.

Preferably, the skin layer is made of a thermosetting resin or a photocurable resin.

Preferably, the modulus or hardness of the skin layer is greater than that of the protective layer.

Preferably, the modulus or hardness of the skin layer is at least three times greater than that of the protective layer.

Preferably, the optical fiber structure according to the present invention further comprises at least one intermediate layer interposed between the protective layer and the shell layer.

Preferably, the intermediate layer is made of a thermosetting resin or a photocurable resin.

Preferably, the modulus or hardness of the intermediate layer is lower than that of the skin layer.

Preferably, the modulus or hardness of the intermediate layer is lower than that of the protective layer.

Preferably, the shape of the polymer beads is any one of spherical, crushed spherical, oval, concave or hemispherical, spread hemisphere.

Preferably, the optical fiber structure according to the present invention further comprises an additional coating layer on the protrusion of the polymer bead layer.

Preferably, the coating layer comprises glass or ceramic particles.

Preferably, the polymer bead layer is made of the same material as the shell layer.

In order to achieve the above object, the apparatus for manufacturing pneumatic fibers according to the present invention is provided with at least one spray gun for spraying polymer beads in an oligomer state on the outer surface of an optical fiber layer. And a spraying chamber.

Preferably, the spray gun has a nozzle capable of spraying a plurality of fine spherical beads on the surface of the optical fiber.

Preferably, the spray gun is disposed in plurality at predetermined intervals to uniformly supply polymer beads to the optical fiber.

Preferably, the spray gun is disposed on the same plane about the supply path of the optical fiber.

Preferably, the spray gun is disposed sequentially on the supply path of the optical fiber.

Preferably, the oligomer has a molecular weight of at least 10 g / mol and an elastic modulus of 400 ~ 1000 Mpa.

According to the present invention, a method for manufacturing an optical fiber for pneumatic laying according to the present invention includes the steps of: a) preparing an optical fiber unit or cable for pneumatic laying; b) coating an outer skin layer on the outside of the optical fiber unit or cable; c) spraying a viscous oligomer polymer on the surface of the shell layer in a concave or convex form to form a polymer bead layer; And d) photocuring or thermosetting the polymer bead layer.

Preferably, the step c) is performed after the step b) before the skin layer is cured.

Hereinafter, an optical fiber structure for pneumatic laying according to a preferred embodiment of the present invention, a manufacturing method and apparatus thereof will be described with reference to the accompanying drawings.

1 is a perspective view of an optical fiber unit (2-core ABF) structure according to a preferred embodiment of the present invention, and FIG. 2 is a perspective view of an optical fiber cable (multi-core ABC) structure according to a preferred embodiment of the present invention.

Referring to FIGS. 1 and 2, the optical fiber unit 10 and the optical fiber cable 20 may include one or more optical fibers 11 made of ribbons in which single / multi-cores or single-cores are continuously collected, and the optical fibers 11. At least one circular shell layer 13 provided on the outside, and a polymer bead layer 15 including a plurality of protrusions provided on the outer surface of the circular shell layer 13 is provided. That is, it shows that the polymer beads are imbedded in particulate form on the outer surfaces of the optical fiber unit 10 and the optical fiber cable 20.

The optical fiber 11 is a single mode fiber or a multi mode fiber, and refers to a 250um optical fiber having a diameter of a normal first and second coating. In addition, the optical fiber 11 may include an additional protective layer 12 for protecting the optical fiber and a coloring layer (not shown) colored for identifying the optical fiber.

The optical fiber 11 may be coated independently of one core or two, four, or eight cores collectively. In addition, the optical fiber may form a ribbon form and the ribbon is stacked for ease of use. On the other hand, the optical fiber 11 may be replaced with a reinforcing fiber (not shown), such as aramid (Aramid) instead of a conventional optical fiber to enhance the tensile strength or for easy removal of the coating. .

The optical fiber 11 may have an outer layer 13 together with a buffer layer (not shown) or only a buffer layer to protect the optical fiber, secure the rigidity of the optical fiber unit, and apply the polymer band, or, if necessary, between the outer layer and the buffer layer. An intermediate layer (not shown) may be formed.

The buffer layer is a coating layer directly enclosing the optical fiber and the outer skin layer is a coating layer which is located outside the buffer layer to be in contact with the outside. The intermediate layer is a layer which exists between the buffer layer and the outer layer and buffers the optical fiber and the buffer layer and the outer layer.

The polymer bead layer 15, which is present on the surface of the outer skin layer 13, is UV cured after the annular polymer particles are adhered to the surface of the optical fiber by a spray gun 35 (see FIG. 3).

The coating material used for the outer skin layer 13 is difficult to be installed by air pressure if the modulus is too low, and if it is too high, cracking due to bending occurs, so it is important to select an appropriate modulus and 2.5% strain, 400 ~. About 1000 Mpa is preferable, More preferably, about the same conditions, about 500-800 Mpa are suitable.

The polymer bead layer 15 may use any kind of photocurable (UV) and thermosetting materials. In addition, when the polymer bead layer 13 is present on the buffer layer, the same material as the buffer layer may be used when the polymer bead layer 13 is present.

In addition, the polymer bead layer 13 may have various types of beads as well as convex beads, but this does not affect the fluid traction.

The material of the polymer for using the polymer beads may be a photo-curable acrylate or a thermosetting acrylate, but various other materials are possible. In particular, it is obvious that a material in which a filler such as carbon or talc is added to suppress static electricity generated during the installation process may be possible. Reference numeral 17 is a jelly buffer layer protecting the multi-core optical fiber.

3 is a conceptual diagram of an apparatus for manufacturing pneumatic fibers according to a preferred embodiment of the present invention.

Referring to FIG. 3, the optical fiber manufacturing apparatus 100 for pneumatic installation according to the present invention has a through hole 31 through which a supply path of the optical fiber 11 passes, and surrounds the optical fiber 11 by a predetermined length. And a spraying chamber 30 formed so as to be provided.

The chamber 30 has a spray gun 35 with a nozzle 33 for injecting the polymer. The spray gun 35 is to spray the polymer into a fine particle sphere (Particular bead). Three spray guns 35 are installed around the through hole. The position of each spray gun 35 may be installed in the same plane around the supply path or may be installed at regular intervals along the supply path of the optical fiber. The arrangement of the spray gun 35 can be variously designed by those skilled in the art to have an optimum spraying and deposition efficiency. Reference numeral 40 denotes a curing apparatus, reference numeral 50 denotes an optical fiber winding roller, and reference numeral 60 denotes an optical fiber winding bobbin.

Referring to FIG. 4, which is a plan view of the spraying chamber shown in FIG. 3, the spray gun 35 is disposed at an equal interval of 120 degrees around the optical fiber so as to have an optimum adhesion efficiency and to be evenly distributed on the outer periphery of the optical fiber. do.

Referring to the step of forming the polymer bead layer on the outer skin layer of the optical fiber.

First, an optical fiber unit or optical fiber cable having a predetermined shape and structure is prepared. The optical fiber may be supplied on the supply path while being released from the supply roll (not shown).

Subsequently, the polymer in an oligomer state is sprayed onto the surface of the outer skin layer 13 of the optical fiber 11 by using the spray gun 35. By this process, the spherical polymer is attached to the outer skin layer 13 of the optical fiber 11.

Next, the shape of the polymer beads is fixed by the curing device 40 UV or heat source. Generally, the polymer in the oligomer state has a viscosity of about 100 g / mol or more and has a viscosity, and when the spray gun 35 is used, the spherical shape may be maintained while spraying the microparticles.

On the other hand, in order to distribute the polymer beads evenly on the outer skin layer 13 of the optical fiber 11, three spray guns are radially formed at an angle of 120 degrees, and three spray guns are respectively prescribed in the longitudinal configuration. Placement at intervals may result in an overall uniform polymer bead distributed over the optical fiber.

Meanwhile, the process of forming the polymer bead layer 15 on the optical fiber 11 may be sprayed using the spray gun 35 after the outer layer is coated / cured, and the coating material of the outer layer is shortened to shorten the process. After the polymer beads are sprayed using the spray gun in the uncured state, the outer skin layer and the polymer bead layer 15 may be simultaneously cured.

As described above, the optical fiber structure for pneumatic laying according to the present invention, and a manufacturing method and apparatus thereof have the following effects.

First, there is no need for a separate raw material to impart fluid drag forces, such as polymer beads, glass beads, or ceramic beads, and to blend these materials into the resin. No pre-stirring process is required.

Second, since the polymer bead layer for imparting fluid traction is spherical as the polymer is sprayed, the polymer bead layer becomes the same basic raw material as the buffer coating layer, thereby solving the conventional interface separation problem. In addition, it is possible to prevent bending crack formation due to material nonuniformity between material domains due to the formation of protrusions through the same material coating.

Thirdly, since the coating can be finished at once with a single material, no further processing by pre-stirring is necessary. In addition, since a large amount of beads (bead) itself is not required, the raw material price is also low, and it is possible to maintain a clean working environment by suppressing problems such as scattering of glass powder.

Various modifications of the invention are possible by those skilled in the art without departing from the scope and spirit of the invention. The present invention should not be limited by the illustrative embodiments described above, but is not limited to the following claims and their equivalents.

1 is a perspective view of an optical fiber unit (2-core ABF) structure according to a preferred embodiment of the present invention.

2 is a perspective view of an optical fiber cable (multi-core ABC) structure according to a preferred embodiment of the present invention.

3 is a conceptual diagram of an apparatus for manufacturing pneumatic optical fibers in accordance with a preferred embodiment of the present invention.

4 is a plan view of the spraying chamber shown in FIG.

<Description of the symbols for the main parts of the drawings>

10 ... optical fiber unit 11 ... optical fiber 13 ... round outer layer

15 Polymer layer 20 Fiber optic cable 30 Spraying chamber

31 ... Through Hole 33 ... Nozzle 35 ... Spray Gun

40 Curing device 50 Winding roller 60 Winding bobbin

Pneumatic optical fiber manufacturing device

Claims (26)

In the air pressure optical fiber structure, which is installed inside the tube using air pressure, and includes an outer skin layer provided on the outside of at least one optical fiber, And a polymer bead layer having a predetermined shape provided on an outer surface of the shell layer. The method of claim 1, The polymer bead layer is a pneumatic laying optical fiber structure, characterized in that the convex photocured or thermoset after the spherical sprayed polymer of the oligomer (oligomer) state on the surface of the outer layer. The method according to claim 1 or 2, The optical fiber structure for pneumatic installation, characterized in that the optical fiber is a single or multi-mode optical fiber. The method according to claim 1 or 2, At least any one of a protective layer or a paint layer provided in the outer shell layer, characterized in that the pneumatic laying optical fiber structure. The method according to claim 1 or 2, And at least one fiber or wire having a higher tensile strength than the optical fiber. The method of claim 5, The tensile strength reinforcing fiber is a Kevlar or FRP fiber structure for pneumatic laying. The method according to claim 1 or 2, The optical fiber structure for pneumatic laying, characterized in that the optical fiber is present in the form of an independent single core or ribbon (Ribbon). The method according to claim 1 or 2, The outer skin layer is a pneumatic laying optical fiber structure, characterized in that made of a thermosetting resin or photocurable resin. The method of claim 4, wherein Modulus or hardness of the shell layer is larger than that of the protective layer. The method of claim 9, Modulus or hardness of the outer layer (Modulus) or the optical fiber structure for pneumatic laying, characterized in that more than three times larger than that of the protective layer. The method of claim 4, wherein And at least one intermediate layer interposed between the protective layer and the shell layer. The method of claim 11, The intermediate layer is a pneumatic laying optical fiber structure, characterized in that made of a thermosetting resin or photocurable resin. The method of claim 11, The modulus or hardness of the intermediate layer is lower than that of the envelope layer. The method of claim 11, Modulus or hardness of the intermediate layer is lower than that of the protective layer. The method of claim 1, The shape of the polymer beads is spherical, crushed spherical, elliptical, concave or hemispherical, spread hemispherical optical fiber structure, characterized in that any one. The method of claim 1, And a further coating layer on the protrusion of the polymer bead layer. The method of claim 16, The coating layer is a pneumatic optical fiber structure, characterized in that containing glass or ceramic particles. The method according to claim 1 or 2, The polymer bead layer is a pneumatic laying optical fiber structure, characterized in that made of the same material as the shell layer. And a spraying chamber provided with at least one spray gun for spraying polymer beads in an oligomer state on a surface of an outer layer of the optical fiber. The method of claim 19, The spray gun is a pneumatic optical fiber manufacturing apparatus characterized in that it comprises a nozzle for injecting a plurality of fine spherical beads on the surface of the optical fiber. The method of claim 19, The spray gun is a pneumatic laying optical fiber manufacturing apparatus, characterized in that a plurality of arranged at a predetermined interval to uniformly supply the polymer beads to the optical fiber. The method of claim 21, The spray gun is a pneumatic laying optical fiber manufacturing apparatus, characterized in that disposed on the same plane around the supply path of the optical fiber. The method of claim 21, The spray gun is a pneumatic optical fiber manufacturing apparatus, characterized in that arranged sequentially on the supply path of the optical fiber. The method of claim 19, The oligomer has a molecular weight of at least 10g / mol and an optical fiber manufacturing apparatus for pneumatic laying, characterized in that it has an elastic modulus of 400 ~ 1000 Mpa. a) preparing an optical fiber unit or cable for pneumatic laying; b) coating an outer skin layer on the outside of the optical fiber unit or cable; c) spraying a viscous oligomer polymer on the surface of the shell layer in a concave or convex form to form a polymer bead layer; And and d) photocuring or thermosetting the polymer bead layer. The method of claim 25, And a step c) after the step b) before the shell layer is cured.