KR100326504B1 - Fiber optic package - Google Patents

Abstract

The optical fiber package of the present invention applies a friction enhancer to the smooth surface of the bobbin or mandrel on which the optical fiber is wound. The friction enhancer eliminates the need for a separate base structure to establish and maintain a winding path for the fiber by adhering the initial layer of fiber to the smooth surface of the bobbin. In addition, the friction enhancer prevents lateral movement in the initial layer of fiber relative to the bobbin. The friction enhancer according to the invention is preferably a plastic material such as room temperature (RTV) silicone and styrene butadiene rubber (SBR). In addition, the optical fiber package of the present invention can combine the use of a friction enhancer between the fiber initial layer and the bobbin, as well as an adhesive coating applied along the length of the optical fiber. Thus, a stable package of optical fiber strands is established, which can be used in situations or environments that require rapid distribution of the fiber without adversely affecting the physical or communication properties of the optical fiber.

Description

Fiber optic package

Technical field

The present invention relates to a stable package of elongated strands.

Background of the Invention

Weapon and communication systems have been developed or are under development using optical fibers for two-way communication between two or more moving objects, or between a moving object and a guidance station. Such use includes communication lines between aircraft, between aircraft and ships, or projectiles such as missiles and control systems of oscillation bases. Advantageously, the use of optical fiber for this kind of communication excludes electromagnetic interference and unnecessary interference.

However, there are some drawbacks to the use of fiber that do not appear in other forms of communication. Fiber optics are less robust than metallic conductors and prone to breakage. In addition to breakage, optical communication performance can be degraded by fine bending in the fiber caused by bending or other stress that the fiber is susceptible to. This damage to the optical fiber not only reduces the durability of the fiber, but also results in a loss in strength and capacity of the optical fiber.

Typical optical fiber applications in weapon systems include the packaging of continuous lengths of optical fibers on carrier bobbins located inside the transport mechanism. Such transport mechanisms are referred to as confined vehicles. One end of the fiber is attached to an actuating mechanism in the medium, while the other end of the fiber is connected to a control or communication station at the oscillation base. During and after the oscillation, bidirectional communication with the medium is conducted.

For the use of such a device, one must have a reliable and compact fiber optic package that can be placed in the transport mechanism and allows for reliable deployment of the fiber during the flight of the medium. The use of metallic conductors for guiding or controlling oscillated media is disclosed in US Pat. Nos. 3,114,456 and 3,319,781. As described herein, the properties of the optical fiber represent difficulties that were not included in the use of the metal conductor for communication. There is a need for specialized treatments that facilitate the separation of optical fibers from carrier bobbins at relatively high rates.

The introduction of optical fibers for use in more sudden environments, such as in underwater cables or military applications, is one problem that more stringent conditions must be applied to the physical properties of the fibers. In addition, extremely long lengths of fiber may be required and may be obtained by splicing multiple lengths obtained using conventional manufacturing techniques. For this and other purposes, splicing away the coating from the end portions of the two fibers where the ends dissolve to each other provides a suitable means for joining the ends of the two glass fibers with water solubility loss. .

Spliced end portions from which the coating layer has been removed must be recoated to maintain stringent requirements on the dimensional and strength measures associated with the coated fibers. Typically, when the original coating layer is removed from the end portions along the overlapped portion of the outer surface of the raw material adjacent the radial plane, the ash coating is adjacent to the original coated portion of the spliced fiber along the exposed radial plane. To make contact. The coating layer is then cured to produce a recoated spliced area with a larger cross section than the optical fiber with the original coating layer.

In a typical constrained conveying device, the optical fiber wound on the dispensing device and connected to the guide system is distributed by removing the conveying device. For the constrained transport mechanism, the winding of the optical fiber in the distribution device must be achieved in an accurate manner. Otherwise, distribution may be stopped. If the cross section of the recoated spliced portion crossing the longitudinal axis of the optical fiber is not the same as the cross section of the optical fiber as originally coated, it can be seen that the shape wound on the dispensing mechanism is not uniform. This causes problems in fiber distribution following the oscillation of a tethered vehicle. This has been solved. Recoated splicing with the same transverse cross section as unspliced was achieved by the use of the method and apparatus described in US Pat. No. 4,865,411.

Another problem with guiding the optical fiber of a constrained conveying device is the successful release of the fiber from the carrier bobbin as the bobbin is pushed together with the medium. The leading end of the optical fiber is connected to the guide system for controlling the travel path of the transport mechanism. This is important for the fiber to be dispensed from the bobbin without the occurrence of breakage, otherwise the fiber will break and the control system will not operate. The meticulously wrapped package contributes to the successful distribution of the fiber. In addition, the line must not only be wound correctly, but the wrap must remain in place during handling and when deployed. In other words, the fiber optic package should be fairly stable. On the other hand, the distribution must occur easily without the need for a large pulling force to remove from the fiber of each line from the carrier bobbin.

In an optical fiber package for use in constrained conveying devices, multiple optical fibers are wound around the wire of the base layer. The adhesive between each fiber acts to grip the packages with each other to form a stable structure that is resistant to external shock and vibration. Preferably, the adhesive used to hold the wires together should have a minimal effect on the optical performance of the wound optical fiber, with the controlled force at the point where the optical fiber is peeled off as the outermost rotation is wound at high speed. It must be distributed. Referring to US Pat. No. 4,950,049, it is shown that these requirements are somewhat contrary to the requirements for the bonding system.

What is necessary, but not adequately present in the existing art, is a reliable and inexpensive method of gripping and securing the base layer of the optical fiber located adjacent to the tub surface of the bobbin or mandrel on which the optical fiber is to be wound. Means for fixing the base layer of the fiber to the bobbin need to prevent all lateral movement of the fiber. If lateral movement of the initial layers of the fiber occurs, disturbances in the required winding configuration develop, followed by distribution failure.

Typically, existing systems use a separate base structure to establish the proper winding path of the optical fiber that follows during the winding. The most commonly used base structure is a precision stainless steel wire or other cylindrical wire that is meticulously wound onto the bobbin surface. Thereafter, the optical fiber is wound into groove portions formed by further wire winding. When this technique is used, the sheath of the cylindrical material remains around the bobbin and becomes part of the optical fiber package.

An alternative method of providing the groove includes forming the groove by covering the bobbin surface with ceramic material and then identifying the surface with a cylindrical forming mechanism such as a plastic short filament or wire. Then, by removing the cylindrical forming mechanism, the optical fiber is wound onto the bobbin by leaving a "track" in the fibrous ceramic material. Another alternative, but expensive, method is to form grooves in the bobbin surface itself by an extremely precise machining or molding process. However, in each of the alternative methods described above, the size ratio of the fibers to be wound and the groove formation in the base layer structure must be closely matched to control the required package configuration.

What is still needed is a package of longer and longer fiber strands that is more reliable and stable. In particular, in-demand methods and apparatus must provide more productive bobbins in which the optical fibers are meticulously wound, and the bobbin or mandrel and the inner layers of the fibers must be held together by friction enhancers. Friction enhancers should allow the package to stabilize dispensing at relatively high speeds. In addition, the process should be able to be easily repeated from one bobbin to another.

Summary of the Invention

The problems in the prior art can be solved by the method and apparatus of the present invention.

details

Referring to FIG. 1, a manufacturing line is schematically shown that is used to provide an elongated strand material coated with an adhesive such as, for example, an optical fiber. Adhesive coated optical fibers are used to provide a stable and accurately wound optical fiber package. The line, referred to by reference numeral 20, comprises a spool 21 of sheathed optical fiber 22 (see FIG. 2). As can be seen in the second diagram, the optical fiber 22 includes a core 24, a coating 26, and a coating layer 27. Instead of a single cladding layer 27, a double cladding layer can be used, which is well known. Typically, the outer diameter of the coated optical fiber 22 is 250 μm. The term optical fiber hereafter is used to refer to an optical fiber having a single or double protective coating layer.

Referring to FIG. 1, the optical fiber 22 is dispensed from the supply spool 21, positioned vertically in the preferred embodiment of FIG. 3, and advanced along a travel path through the diameter gauge 29. FIG. The diameter measuring gauge 29 is commercially available, such as a brand name: a laser microphone micrometer, and can be used from the Techmet company.

Thereafter, the coated optical fiber is advanced through an applicator 30. Applicator 30 acts to apply adhesive 32 to the coated optical fiber. In the final fiber optic package, the adhesive holds the wires together before the fiber is distributed.

Applicator 30 includes an application cup 34 for holding a fixer of adhesive in liquid form (see FIG. 3). After each successive increase in the length of the optical fiber is removed through the fixer, it is moved through the dimensioning die 36. Dimensioning die 36 may be a rigid die or may be a flowable tip. If the die is a flowable tip having the cladding 32 by exiting the applicator 30, the inner diameter of the tip may be a collet or rainbow (described in US Pat. No. 4,370,355 and incorporated herein by reference). iris) configuration can be changed.

In a preferred embodiment of the invention, a friction enhancer is applied to the surface of the carrier bobbin to ensure that the initial layer of fiber is properly maintained in the required position relative to the carrier bobbin. The use of such friction enhancers alleviates the need for a base layer of wire. Therefore, if used in combination, the adhesive will act to maintain the necessary relationship configuration and position between adjacent optical fibers, while the friction enhancer will provide significant stability between the initial layer of fiber being wound and the surface of the carrier bobbin or spool. Will provide.

A significant number of friction enhancements and adhesives can be applied to the optical fiber to provide a stability package. For example, amorphous or translucent thermoplastics, high melt materials, thermosetting materials, or waxes or other materials capable of forming contact surfaces that bind by heat treatment or by time or solvent irradiation may be used. In a preferred embodiment, the adhesive is a polyvinyl butyl plastic material.

The important thing is that the adhesive must match the special requirements. As mentioned in US Pat. No. 4,950,049, the adhesive must be able to be applied to the optical fiber in the liquid state and not zigzag when the optical fiber is wound on the process spool. It should also be noted that the friction enhancer and / or the adhesive must be able to be processed to continuously develop the adhesive bond between adjacent lines of the optical fiber to be wound on the carrier bobbin. The coupling must not only be subsequent optical fiber packages stable, but also allow the fiber optic wires to be dispensed from the carrier spool without damaging the fiber.

In a preferred embodiment, the adhesive is polyvinyl butyl as described above. The fixer in applicator 30 includes a mixture consisting of polyvinyl butyl and a solvent. In a preferred embodiment, the solvent is methyl ethyl keron.

After the drying and the adhesive treatment in the optical fiber are finished, as described in US Pat. No. 4,950,049, the optical fiber is wound into a plurality of lines on the process spool 44. The winding on the spool 44 must be completed so that the optical fiber is somewhat loosely wound (FIG. 4). By being loosely wound on the intermediate process spool 44, the tension of the optical fiber is about 30 to 40 g.

Then, the spool 44 in which the optical fiber is loosely wound and another spool 50 representing the deployment or carrier bobbin are arranged for rewinding operation (see FIG. 5). Typically, the bobbin 50 is made of metal, plastic, or composite and has a hub that is slightly taped from the flange 51. During such operation, the optical fiber is wound back into a meticulously wrapped package 52 comprising a plurality of layers 54 consisting of a plurality of lines 56, each closely wound from a plurality of lines that are loosely wound. . Only during this rewinding, the tension in the optical fiber is about 100 g. For example, a meticulous winding operation that can be performed in a process as shown in US Pat. No. 4,746,080 is time consuming and ends at a relatively low line speed.

According to a preferred embodiment of the present invention, at least a portion of the surface of the spool or bobbin positioned adjacent the middle of the wound optical fiber initial layer is treated with a friction enhancer to prevent lateral movement of the initial fiber layer relative to the bobbin. Typically, the optical fiber is wound onto a bobbin or mandrel having a taped configuration by starting at the base or larger end of the bobbin barrel.

As mentioned earlier, the existing optical fiber winding mandrel configuration requires the enclosing of the intermediate groove base layer between the smooth barrel surface of the mandrel and the initial layer of fiber being wound. The additional base structure acts to prevent lateral movement of the fiber initial layer with respect to the bobbin. Currently, there are no alternative ways to remove cost and cumbersome groove base surfaces, except for customized bobbin surfaces. If there is no support for the initial layer when using taped bobbins, the fibers tend to slide along the smooth barrel surface towards the small end of the bobbin.

The present invention establishes any form of winding pattern for optical fibers by suitably setting the use of adhesive coated fibers described in the specification and US Pat. No. 4,950,049 in combination with a layer of suitable friction enhancer along the barrel surface of the bobbin. Provides a winding process that does not require the use of grooved base structures. In addition, the present invention entirely eliminates the need for tightly controlling the fiber turn ratio as required for binary. Moreover, the concept of the present invention improves the use of pre-applied adhesive fibers, since the creation of a tight winding allows more contact between the adhesive surfaces.

Particular friction enhancers applied on the winding surface of the bobbin according to the invention are preferably plastic materials such as room temperature vulcanized (RTV) silicon and styrene butadiene rubber (SBR). SBR is a product of Electric Products, Carson, Calif., And is currently marketed as an E-6000 adhesive. SBR shows the flexibility needed to provide a "track" for fibers (short A durometer 70-85), and a sufficiently high surface friction to prevent lateral movement of the fiber pack. In particular, the E-6000 adhesive provides a very stable bond to the surface of the bobbin, regardless of whether the bobbin is made of a metal or polymer composite. It should be noted, however, that well known friction enhancing materials which meet the required standards can be used according to the invention without changing the scope of the invention.

While preferred friction enhancing materials relate to the above, a second embodiment of the present invention includes applying an adhesive that can be treated to be applied to the length of the fiber, the smooth bobbin surface. Thus, referring to FIG. 8, a curve 70 is shown that represents the modular state of the thermoplastic material. At room temperature or in the temperature range below 70 ° C. where the optical fiber is used, the material is in the transparent region 72. At that time, this is not sticky. Thereafter, as the temperature increases, the module decreases and descends through the transition region 74 and continues to be elastic along the portions 76 and 78. The degree of adhesion depends on the elevated temperature and the amount of time during which the thermoplastic is exposed to this temperature value. Bonding is promoted by allowing the composite to be heated in the range shown during portions 74, 76, or 78 of the graph, which govern the amount of bonding required. For some materials, bonding in the transition region may be sufficient.

With reference to FIGS. 9-12, a series of figures is shown illustrating the formation of a modular bond across the contact surface 80 between the adhesive on the fiber initial layer and the adhesive on the surface of the bobbin. Due to the thermoplastic material, molecular bonds cause mutual penetration or movement of the chains that make up the plastic material across the contact boundaries between the contact portions of the adhesive.

The amount of bond is related to the amount of chain penetration that occurs across the contact portions of the adhesive. In addition, the amount of bond is increased to increase the exposure temperature, or the time during which the adhesive is exposed to a given temperature. 10 through 12 illustrate the temperature that is increased by passing temperature through regions 74, 76, 78. The required amount of coupling for a particular application will determine the time or temperature at which the optical fiber is exposed, or both.

Because of the bonding or molecular movement across the contact surface that can be irradiated by comparing FIGS. As can be seen in Figure 9, the portion of the adhesive 320 does not bond across the contact surface 80 prior to processing in the device 60. When treated in the device 60, the adhesive on the contact portion Begins to develop molecular bonds (see FIG. 10), after exposure to a predetermined temperature for a predetermined time, sufficient molecular bonds across contact surface 80 are established to hold the convolutions together (11 and 12 degrees). The result is a stable package of wound fibers that can be handled with confidence that the line is in place, but the bond is not so large that it interferes with the distribution of the fiber from the bobbin. At the level, each successive line is separated from the adjacent line and, when appropriate, an initial layer occurs from the bobbin surface, without any damage to the fiber. It should be recognized that the molecular bonds are at the point of contact that occurs to establish a chain of intersecting planes.

It is important that proper adhesion occurs with any bond of molecular bonds for the adhesive that may occur across the contact surface between the contact portions of adjacent lines and as a result of the proper treatment between the initial layer of fiber and the tub of the bobbin. These materials are thermosets, high melt adhesives, or thermoplastics that are amorphous or translucent. During proper handling of any of these materials, molecular movement across the contact surface between the contact portions occurs. With cooling, molecular bonds are established across the contact surface to ensure the circuit remains in place.

The treatment temperature range for polyvinyl butyl is from about 70 ° C to about 120 ° C. Treatment temperatures for other suitable materials vary, but are generally above 70 ° C. The required level of bonding temperature, or time, is based on the nature of the adhesive used.

The treatment temperature may be provided by a plurality of suitable devices. For example, the installation may include an oven or electromagnetic heating installation. Electromagnetic energy can heat this to bond the adhesive. When electromagnetic energy is used to increase the temperature of the adhesive, the bobbin 50 is made of a nonmetallic material. Moreover, using friction enhancers in accordance with the present invention allows the use of electromagnetic energy to significantly reduce the processing time involved, by eliminating the need for a stainless steel base mixture. In another technique, a vacuum can be used to withdraw air from the gaps between the lines. Vapor or liquid material is introduced to adhere the contact portions of the convolutions to each other. Then, the vacuum is applied again to remove excess material.

By controlling the conduction of the track between the lines on the bobbin 50, damage to the fiber is eliminated during high speed unwinding. Of course, the track time and temperature depend on the particular adhesive applied to the optical fiber.

For thermoplastics in the contact surface between adjacent lines, the variation of the thermoplastics shown in FIG. 8 is reversible. By cooling the adhesive, the joining area along the contact portion of the adjacent lines is fixed or frozen and stabilized with time. When the optical fiber has cooled to ambient temperature, the contact bonding remains at the level achieved during high temperature exposure. Portions of the unbonded surface return to the glassy state as shown in FIG. It facilitates a uniform coating without adhesion at room temperature. Adhesion is generated and controlled by the adhesion of the thermoplastic in the transition and / or elastic regions.

The return of these quadrants of the thick oil's adhesive that do not contact portions of the adhesive on adjacent lines in the glassy state of cooling has the advantage. These surfaces are characterized by a relatively low coefficient of friction. This low coefficient of friction, glassy surface facilitates high speed distribution of the optical fiber. If the surfaces are not so characterized, a payout that includes portions of each circuit that slides over a portion of the other circuit surface will cause some adjacent circuits to move prematurely and interfere with the package. This unnecessary occurrence becomes evident in the distribution of multiple lines followed by entanglement. Advantageously, the low coefficient of friction surface portions of the non-molecularly bonded line avoid multiple distribution to each line that is easily pulled over the surface of the other lines.

For example, a correctly wound fiber optic package 52 is used to control the missile's flight path. In this environment, the bobbin 50 wound around the optical fiber is mounted to the missile 80 (see FIG. 8). The inner end 81 of the optical fiber is connected to the device 83 in the missile, and the leading end 85 of the fiber is connected to the control station 87. Following the missile oscillation base, the flight path is controlled by the control station 87 in communication with the missile 80 via the optical fiber 22. As the missile moves from the control station 87 to the destination 90, the optical fiber is distributed from the unflanged end of the bobbin 50 to maintain communication between the control station and the missile.

1 is a schematic diagram of a manufacturing line used to apply an adhesive to an optical fiber according to the method of the present invention.

2 is a cross-sectional end view of an optical fiber having a coating material and an adhesive.

3 is a schematic representation of a portion of the line shown in FIG.

4 is an end cross-sectional view of a portion of a process spool having a plurality of loosely wound convolutions.

5 is a schematic diagram of fiber movement from a loosely wound line on a process spool to a meticulously wrapped package on a carrier bobbin.

6 is a view of a portion of an optical fiber package including a convolution of an optical fiber wound on a carrier bobbin.

7 is a schematic diagram of an apparatus used to treat adhesive on a convolution of an optical fiber after the optical fiber is wound on a carrier bobbin.

8 is a graph showing the state of a scale factor of a thermoplastic material by heat treatment.

9 through 12 illustrate a series of molecular level schematics of the contact surface between adhesives in adjacent lines of an optical fiber wound on a bobbin as the contacting steps between adhesives in a portion of adjacent lines through transitional steps. Magnified view.

13 is a schematic diagram illustrating the use of the stability package of the present invention.

Explanation of symbols on main parts of drawing

20: process line 22: optical fiber

24 core 26 coating

30: Applicator 36: Die

50: Bobbin 52: Package

Claims (9)

An optical fiber package comprising an optical fiber of a predetermined length disposed in a plurality of convolutions such that at least one portion of the innermost convolution is adjacent to at least a portion of the supporting bobbin, A layer of friction enhancing material for adhering the innermost conduit of the predetermined length of optical fiber to the support bobbin, the friction enhancer being applied directly to a portion of the support bobbin. Fiber optic package. The method of claim 1, The friction enhancer is a room temperature vulcanized (RTV) silicon optical fiber package. The method of claim 1, The friction promoting material is a styrene butadiene rubber (Styrene Butadiene Rubber; SBR) optical fiber package. The method of claim 1, And further comprising a layer of adhesive enclosing an increase in the length of the optical fiber, wherein the adhesive of the layer is, by appropriate treatment, molecularly bonded across the contact surface between the portions of the adhesive, the contact portions of the optical fiber Wherein the adhesives are bonded to each other by molecular bonding, and wherein the adhesives at other parts of the optical fiber have a relatively low coefficient of friction. The method of claim 4, wherein Wherein said adhesive is selected from the group consisting of thermoplastics, solid solution melts, thermosets, solders, and waxes. The method of claim 5, The adhesive is an optical fiber package consisting of a mixture of polyvinyl butyral plastic material and a solvent. In the method for providing an optical fiber package, Covering a portion of the support bobbin with a friction enhancer, Coupling each conduit with at least a portion of another conduit such that the fiber of the predetermined length is wound into a plurality of conduits such that the innermost layer of fiber is bonded to the portion of the support bobbin by the friction enhancing material. How to provide fiber optic package. The method of claim 7, wherein The friction enhancer is room temperature vulcanized (RTV) silicon. The method of claim 7, wherein The friction enhancer is styrene butadiene rubber (SBR).