KR20220029045A - Optical Cable - Google Patents

Abstract

The present invention relates to an optical cable which minimizes an overall outer diameter so that pneumatic installation in a microduct is possible, and secures sufficient tensile strength, so that traction installation is possible during an installation work. The optical cable includes: a plurality of optical fibers; a coating layer surrounding the plurality of optical fibers and made of a polymer resin material; a tensile force reinforcing layer made of a tensile fiber material surrounding the coating layer; and an outer jacket surrounding the outside of the tensile force reinforcing layer.

Description

Optical Cable {Optical Cable}

The present invention relates to an optical cable. The present invention relates to an optical cable that is capable of pneumatic installation in a microduct with a minimized overall outer diameter, while ensuring sufficient tensile strength and also capable of traction installation during installation.

The pneumatic installation method for installing optical cables is a method in which optical cables are blown pneumatically into a narrow micro-duct to be installed.

Recently, the microduct-type conduit is more saturated, and there is a great demand for a technique for narrowing the diameter of the optical cable so that an optical cable having more optical fibers is installed in a pre-installed microduct-type conduit.

However, when designing an optical cable that can be installed in a narrow microduct, only the number of optical fibers accommodated in the optical cable compared to the outer diameter can be considered.

In the pneumatic installation of optical cables, the optical cable can be installed up to several kilometers by pneumatically blowing the propellant mounted on the tip of the optical cable. However, if the protective layer that protects the optical fiber is minimized, disconnection or damage of the optical cable may occur during traction installation.

In addition, when pneumatic installation of an optical cable equipped with as many optical fibers as possible, the magnitude of friction between the outer jacket of the optical cable and the microduct-type conduit is a factor that determines the pneumatic installation distance, and the outer jacket of the optical cable also protects the internal optical fiber. It provides tensile strength and determines the flexibility of optical cables, which are important characteristics during pneumatic installation, so the thickness and material selection are important.

An object of the present invention is to provide an optical cable that is capable of pneumatic installation in a microduct with a minimized overall outer diameter, while ensuring sufficient tensile strength and also capable of traction installation during installation.

In order to solve the above problems, the present invention provides a plurality of optical fibers; a coating layer surrounding the plurality of optical fibers and made of a polymer resin material; a tensile force reinforcing layer made of a tensile fiber material surrounding the coating layer; and an outer jacket surrounding the outside of the tensile force reinforcing layer, wherein a maximum of 12 optical fibers is provided, a total outer diameter of which is 2.2 millimeters (mm) or less, and a virtual circle in which each optical fiber is inscribed from the center of the optical fibers It is possible to provide an optical cable characterized in that the ratio of the minimum radius to the maximum radius of is 0.6 or more.

In addition, at least one filler member is further provided in the coating layer together with the optical fiber, the filler member may have a diameter corresponding to the optical fiber, and the sum of the optical fiber and the filler member may be at most 12.

And, when the sum of the number of the optical fiber and the filler member is 4 or less, the total outer diameter may be 1.3 to 1.9 millimeters (mm).

Here, when the sum of the number of the optical fiber and the filler member is 5 to 8, the total outer diameter may be 1.5 to 2.1 millimeters (mm).

In this case, when the sum of the number of the optical fiber and the filler member is 9 to 12, the total outer diameter may be 1.6 to 2.2 millimeters (mm).

And, the tensile force reinforcing layer may be provided with a plurality of aramid yarn (Aramid yarn).

In addition, the tensile force reinforcing layer is composed of 500 to 1500 denier (Denier) aramid yarn 3 to 5,

Tensile strength according to the international standard IEC 60794 test standard of the optical cable may be 150 to 270N.

In addition, the polymer resin constituting the coating layer is an acrylate-based resin, and the coating layer may be configured by an Ultraviolet (UV) curing method.

And, the outer jacket may be made of a high-density polyethylene (HDPE) material.

Here, the thickness of the outer jacket may be 0.23 to 0.27 millimeters (mm).

In this case, the optical fiber may be a narrow optical fiber having a diameter of 180 to 220 micrometers (㎛) or a general optical fiber having a diameter of 230 to 270 micrometers (㎛).

The optical cable according to the present invention has a total outer diameter of 2.2 millimeters (mm) or less while accommodating up to 12 optical fibers, so that pneumatic installation is possible in a microduct with an inner diameter of about 3.5 millimeters (mm). The tensile strength of the optical cable is improved by providing a tensile force reinforcing layer composed of fibers, so that traction installation work may be possible if necessary.

In addition, the optical cable according to the present invention reinforces the tensile strength of the optical cable when the tensile force reinforcing layer is made of aramid yarn and at the same time facilitates the peeling operation of the outer jacket, thereby improving the workability when connecting the optical cable. there is.

1 shows a cross-sectional view of an optical cable according to an embodiment in which the number of optical fibers according to the present invention is two.
2 shows a cross-sectional view of an optical cable according to an embodiment in which the number of optical fibers according to the present invention is four.
3 is a cross-sectional view of an optical cable according to an embodiment in which the number of optical fibers according to the present invention is six.
4 is a cross-sectional view of an optical cable according to an embodiment in which the number of optical fibers according to the present invention is eight.
5 is a cross-sectional view of an optical cable according to an embodiment in which the number of optical fibers according to the present invention is ten.
6 is a cross-sectional view of an optical cable according to an embodiment in which the number of optical fibers is 12 according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed subject matter may be thorough and complete, and the spirit of the invention may be sufficiently conveyed to those skilled in the art. Like reference numbers refer to like elements throughout.

In the case of a narrow optical cable, it is possible to install it inside a microduct in a pipe that is up to several kilometers long by the pneumatic installation method.

The diameter of the microduct pre-installed in the conduit may be configured to have an inner diameter according to a conventional standard, etc., and the diameter of the optical cable pneumatically installed inside the microduct may be limited according to the microduct inner diameter.

For example, in the case of pneumatic laying of an optical cable in a microduct having an inner diameter of 3.5 millimeters (mm), which is already widespread in Europe, the outer diameter should be 2.2 millimeters (mm) or less, preferably 2.0 millimeters (mm) or less. Stable work is possible.

In addition, most optical cables can be installed in a pneumatic installation method in the microduct, but depending on the installation environment, pneumatic installation and traction installation may be applied together in some sections of the microduct.

In order to accommodate as many optical fibers as possible inside an optical cable with a limited outer diameter according to the increase in optical communication demand, a method of reducing the thickness of an anticorrosive layer or cable jacket excluding optical fibers inside the cable may be considered. For example, it becomes a factor of lowering the tensile strength, etc., and the installation method such as the traction installation described above cannot be used.

Therefore, even if the optical communication capacity is increased by accommodating as many optical fibers as possible in the optical cable having a limited outer diameter, mechanical properties capable of withstanding traction installation must also be secured.

1 to 6 are cross-sectional views showing various embodiments of the optical cable 100 according to the present invention.

1 to 6, the optical cable 100 according to the present invention includes a plurality of optical fibers 10, a coating layer 20 made of a polymer resin material surrounding the optical fiber 10, and the coating layer 20 around It may be configured to include a tensile force reinforcing layer 30 made of a tensile fiber material and an outer jacket 40 surrounding the tensile force reinforcing layer 30 .

In addition, in the optical cable 100 according to the present invention, up to 12 optical fibers 10 are provided, and the total outer diameter (Dc) is at most 2.2 millimeters (mm) or less, and the inner diameter is 3.5 millimeters (mm) or less. Pneumatic installation is possible in the duct.

It is known that the outer diameter of the optical cable to be pneumatically laid into the microduct must be about 80 percent (%) or less, preferably about 70 percent (%) or less of the inner diameter of the micro duct to enable stable long-distance pneumatic installation.

1 and 2, when there are two or four optical fibers 10 constituting the optical cable 100, the total outer diameter (Dc) of the optical cable may be 1.3 to 1.9 millimeters (mm). 3 and 4, when there are 6 or 8 optical fibers 10 constituting the optical cable 100, the total outer diameter (Dc) of the optical cable may be 1.5 to 2.1 millimeters (mm). 5 and 6, when there are 10 or 12 optical fibers 10 constituting the optical cable 100, the total outer diameter (Dc) of the optical cable may be 1.6 to 2.2 millimeters (mm). there is.

As such, even if a maximum of 12 optical fibers 10 are provided inside the coating layer 20 of the optical cable 100, the total outer diameter of the optical cable is 2.2 millimeters (mm) or less, and the inner diameter of the microduct is 3.5 millimeters (mm) or less. It was confirmed that the total outer diameter (Dc) of the optical cable 100 based on the inner diameter of the optical cable 100 can be 70% or less of the microduct inner diameter, specifically, up to about 63 percent (%).

The optical fiber 10 is provided with a central core and a cladding layer surrounding the core, wherein the core uses a glass optical fiber made of silica with a high refractive index, and the cladding layer includes It is composed of glass or synthetic resin made of silica having a relatively lower refractive index than the core, and serves to transmit a signal by causing total reflection of light passing through the center.

In addition, a color coating layer may be provided on the outermost surface of the optical fiber 10 to provide different colors to the optical fiber 10 so that the optical fiber 10 can be easily distinguished during a disconnection operation. For example, the color coating layer may be formed by applying a liquid carrier in which colored pigment particles are dispersed on the surface of the optical fiber 10 .

A single-mode optical fiber having a core diameter of several μm is referred to as a single-mode optical fiber, and a multi-mode optical fiber having a core diameter of several tens of μm is referred to as a step-type optical fiber or a hill-type optical fiber according to the refractive index distribution of the core. The outer diameter of the optical fiber 10 may be selected from a narrow optical fiber having a diameter of 180 to 220 micrometers (㎛) or a general optical fiber having a diameter of 230 to 270 micrometers (㎛).

As the coating layer 20 surrounding the optical fiber 10 as a whole, in order to stably support and accommodate the optical fiber 10, a photo-curable polymer resin cured by ultraviolet (UV) irradiation is used, preferably acrylate. (Acrylate) may be composed of a polymer resin.

Here, 4,4-bis(dimethylamino)benzophenone (4,4′) is added to an acrylate-based polymer resin as a component of the coating layer 20 so that the coating layer 20 is cured quickly when irradiated with ultraviolet rays. A photocurable initiator such as (diethylamino)benzophenone) may be additionally added.

The coating layer may be coated to surround the entire perimeter of the plurality of optical fibers, and to be cured in a state that is permeated to the inside so that there is no empty space between the optical fibers to form a solid core or to form a core between optical fibers or between optical fibers and a filler member. It can be configured to have some space.

In addition, at least one filler member 50 may be further provided in the coating layer 20 together with the optical fiber 10 .

The embodiment shown in FIG. 1 is provided with two optical fibers and two filler members, and thus may have a cross-sectional structure similar to that of the optical cable shown in FIG. 2 in which only four optical fibers are accommodated as a whole.

If the core is configured by accommodating only two optical fibers inside the coating layer, it is not easy to configure the optical cable cross-sectional shape in a circular shape and it is difficult to secure sufficient tensile strength. An optical cable having a structure similar to that of the optical cable shown in FIG. 2 provided with four may be configured.

For the same reason, the embodiment shown in FIG. 3 is provided with six optical fibers and two filler members, and may have a cross-sectional structure similar to that of the optical cable shown in FIG. 4 in which only eight optical fibers are accommodated as a whole, and The embodiment may have a cross-sectional structure similar to that of the optical cable shown in FIG. 6 in which 10 optical fibers and two filler members are provided, and only 12 optical fibers are accommodated as a whole.

All the embodiments shown in FIGS. 1 to 6 minimize the outer diameter of the optical cable by minimizing the empty space inside the core as much as possible, and the optical fiber or the filler member is circumscribed to prevent movement of the optical fiber or the filler member during the curing process of the coating layer. can

In this case, the number and arrangement shape of the optical fiber and the filler member may be variously changed.

The filler member 50 is configured in a circular cross section to correspond to the size and shape of the optical fiber 10 to maintain the roundness of the optical cable 100, and when the optical cable 100 is pneumatically installed or the optical cable 100 It is also possible to provide a function of minimizing damage to the coating layer 20 and the optical fiber 10 by uniformly distributing the bending stress, the installation tension, or the tensile force acting on the optical fiber 10 .

In order to configure an optical cable by arranging an optical fiber in a limited space, but to minimize the diameter of the optical cable, the embodiments shown in FIGS. 1 to 6 are

While the diameter of the optical cable is minimized, the minimum thickness of the optical fiber coating layer must be secured in order to achieve the purposes of securing roundness and preventing damage to the optical fiber. It is desirable that the circumscribed circle radius variation be minimized.

That is, it is preferable that the ratio of the minimum circumscribed circle radius to the maximum circumscribed circle radius among the virtual circumscribed circle radii of each optical fiber satisfies the condition of 0.6 or more.

In the optical cable embodiment having a 2-core or 4-core optical fiber shown in FIGS. 1 and 2 , the radius of the virtual circumscribed circle is the same, so the ratio of the minimum circumscribed circle radius (r _min ) to the maximum circumscribed circle radius (r _max ) is 1, and the optical cable embodiment with 6-core or 8-core optical fiber shown in FIGS. 3 and 4 has a ratio of the minimum circumscribed circle radius (r _min ) to the maximum circumscribed circle radius (r _max ) of 0.65, and FIGS. 5 and In the optical cable embodiment having a 10-core or 12-core optical fiber shown in FIG. 6 , the ratio of the minimum circumscribed circle radius (r _min ) to the maximum circumscribed circle radius (r _max ) was measured to be about 0.82.

That is, when an optical fiber having a circular cross-section is disposed in a space of a circular cross-section, the size or roundness of the empty space varies depending on the number. It can be confirmed that the ratio of the minimum circumscribed circle radius (r _min ) to the maximum circumscribed circle radius (r _max ) is preferably 0.6 or more.

A tensile force reinforcing layer 20 composed of tensile fibers around the coating layer 20 is provided to reinforce the tensile strength of the optical cable 100, and the tensile fibers are fibers having excellent tensile properties, for example, aramid yarn. (Aramid yarn) may be provided in a transverse winding or longitudinal state inside the outer jacket 40 .

In addition, the tensile fiber may be configured to be twisted in the S-Z direction around the coating layer 20 , and a pitch of various ranges may be determined according to the installation environment required for the optical cable 100 .

Here, the denier of the aramid yarn constituting the tensile force reinforcing layer 30 may be appropriately selected in the range of 500 to 1500 denier, and the tensile force reinforcing layer 30 may be composed of a plurality of aramid yarns.

When the denier of the aramid yarn is more than 1500, the total outer diameter (Dc) of the optical cable 1000 exceeds 2.2 millimeters (mm), so it is not suitable for the installation of microducts with an inner diameter of 3.5 millimeters (mm) or less, There is a problem in that the bonding force between the coating layer 20 and the outer jacket 40 is greatly reduced.

On the other hand, when the denier of the aramid yarn is less than 500, when the tensile force reinforcing layer 30 is formed with the aramid yarn, the total outer diameter (Dc) of the optical cable 100 does not exceed 2.2 millimeters (mm), so pneumatic installation is possible However, there is a problem in that a large number of aramid yarns are required during the manufacture of the optical cable 100, thereby increasing the manufacturing cost.

Therefore, the denier of the aramid yarn constituting the tensile force reinforcing layer 30 is preferably 500 to 1500, and more preferably, in the case of an optical cable having a 2-core to 12-core optical fiber, the aramid yarn is composed of 800 to 1200 denier. In this case, it can be confirmed that the optimal tensile strength and stripping characteristics of the optical cable 100 can be realized.

Here, when the tensile force reinforcing layer 30 is composed of four aramid yarns of 1000 denier are transversely wound, the tensile strength of the optical cable 100 is measured based on the test standards stipulated in IEC 60794 for optical cables, etc. It was confirmed that the tensile strength of the optical cable 100 was secured to about 150 to 270N, so that it was possible to secure a level of tensile strength capable of pneumatic installation as well as traction installation.

Conventional optical cable is not provided with the tensile force reinforcing layer 30 so that when the outer jacket 40 is pulled and held, the outer jacket 40 and the coating layer 30 attached to each other are stretched together with the outer jacket 40 Thus, there was a problem in that the outer jacket 40 and the coating layer 30 constituting the optical cable 100 are easily cut by an external force.

In general, the conventional tensile strength (N) of the optical cable was a level obtained by multiplying the weight (g) per unit length of the optical cable by the standard gravitational acceleration. For example, the tensile strength of the optical cable containing 2 to 12 optical fibers inside is 20 It was in the range of 30N to 30N, but it was experimentally confirmed that the optical cable 100 according to the present invention was improved to about 5 times or more of the tensile strength of the conventional optical cable in which the tensile force reinforcing layer was omitted by having a tensile force reinforcing layer.

In addition, the tensile force reinforcing layer 30 can obtain the effect of improving the peelability of the outer jacket 40 . That is, in the branching or connecting operation of the optical cable performed at the end of the optical cable, the peeling of the outer jacket is essentially required.

If the tensile force reinforcing layer 30 is not provided, since the interface between the coating layer 20 and the outer jacket 40 may be in close contact or adhered, a knife or the like is inserted to remove the outer jacket 40 . In the process, there is a risk of damage to the coating layer 20 and the optical fiber 10, and a problem that the peeled cross section is not smooth occurs.

The outer jacket 40 may be made of a polymer material to maintain the original shape of the optical cable 100 and to reduce friction with the inner circumferential surface of the microduct when the optical cable 100 is pneumatically installed in the microduct.

For example, the outer jacket 40 is a polyethylene (Polyethylene)-based polymer resin having a low coefficient of friction and excellent tensile strength, for example, very low density polyethylene (VLDPE), linear low density polyethylene (LLDPE), low density polyethylene (LDPE), medium Density polyethylene (MDPE), high-density polyethylene (HDPE), etc. alone or may be configured by using a mixture thereof, preferably the outer jacket 40 is a high-density polyethylene (High-density polyethylene; HDPE) resin material can be configured.

Here, the thickness (Dt) of the outer jacket 40 is preferably configured to be 10 to 20 percent (%) of the total outer diameter (Dc) of the optical cable 100, and the total outer diameter of the optical cable 100 ( When Dc) is 1.3 to 2.2 millimeters (mm), the thickness Dt of the outer jacket 40 may be 0.23 to 0.27 millimeters (mm).

When the thickness (Dt) of the outer jacket 40 is less than 10 percent of the total outer diameter (Dc) of the optical cable 100, or the thickness (Dt) of the outer jacket 40 is less than 0.23 millimeters (mm) The outer jacket 40 of the optical cable 100 is easily worn or damaged by external friction, so that the optical fiber 10 is easily damaged, and the overall tensile strength of the optical cable 100 is lowered.

On the other hand, the thickness (Dt) of the outer jacket 40 is greater than 20 percent (%) of the total outer diameter (Dc) of the optical cable 100 or the thickness (Dt) of the outer jacket 40 is 0.27 millimeters (mm), the weight of the outer jacket 40 relative to the total weight of the optical cable 100 is excessively increased, so that it is impossible to flexibly pneumatically lay the optical cable 100 in the duct, and also pneumatic Since the outer jacket 40 easily thermally expands due to the temperature rise due to external friction during installation, and the tensile strength of the optical cable 100 decreases again, the thickness of the outer jacket 40 is 0.23 to 0.27 millimeters ( mm) is preferred.

Although the present specification has been described with reference to preferred embodiments of the present invention, those skilled in the art can variously modify and change the present invention without departing from the spirit and scope of the present invention as set forth in the claims described below. will be able to carry out Therefore, if the modified implementation basically includes the elements of the claims of the present invention, all should be considered to be included in the technical scope of the present invention.

100: optical cable
10: optical fiber
20: coating layer
30: tensile strength reinforcement layer
40: outer jacket
50: filler member

Claims (11)

a plurality of optical fibers;
a coating layer surrounding the plurality of optical fibers and made of a polymer resin material;
a tensile force reinforcing layer made of a tensile fiber material surrounding the coating layer; and
and an outer jacket surrounding the outside of the tensile force reinforcing layer.
The optical fiber is provided with a maximum of 12, and the total outer diameter is composed of a maximum of 2.2 millimeters (mm) or less,
The optical cable, characterized in that the ratio of the minimum radius to the maximum radius of the virtual circle inscribed in each optical fiber from the center of the optical fibers is 0.6 or more. The method of claim 1,
An optical cable, characterized in that at least one filler member is further provided in the coating layer together with the optical fiber, the filler member has a diameter corresponding to the optical fiber, and the sum of the optical fiber and the filler member is at most 12. 3. The method of claim 2,
An optical cable, characterized in that the total outer diameter is 1.3 to 1.9 millimeters (mm) when the sum of the number of the optical fiber and the filler member is 4 or less. 3. The method of claim 2,
An optical cable, characterized in that when the sum of the number of the optical fiber and the filler member is 5 to 8, the total outer diameter is 1.5 to 2.1 millimeters (mm). 3. The method of claim 2,
An optical cable, characterized in that when the sum of the number of the optical fiber and the filler member is 9 to 12, the total outer diameter is 1.6 to 2.2 millimeters (mm). The method of claim 1,
The optical cable, characterized in that the tensile force reinforcement layer is provided with a plurality of aramid yarn (Aramid yarn). 7. The method of claim 6,
The tensile force reinforcing layer is composed of 3 to 5 aramid yarns of 500 to 1500 denier,
The optical cable, characterized in that the tensile strength according to the international standard IEC 60794 test standard of the optical cable is 150 to 270N. The method of claim 1,
The polymer resin constituting the coating layer is an acrylate-based resin, and the coating layer is formed by an Ultraviolet (UV) curing method. The method of claim 1,
The outer jacket is an optical cable, characterized in that it is made of a high-density polyethylene (HDPE) material. According to claim 1,
The optical cable, characterized in that the outer jacket thickness is 0.23 to 0.27 millimeters (mm). The method of claim 1,
The optical cable is an optical cable, characterized in that the optical fiber is a narrow optical fiber having a diameter of 180 to 220 micrometers (㎛) or a general optical fiber having a diameter of 230 to 270 micrometers (㎛).

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