CN110609364A

CN110609364A - Optical connector with adhesive

Info

Publication number: CN110609364A
Application number: CN201910897414.1A
Authority: CN
Inventors: 张海富
Original assignee: Jiangsu Kunzai New Material Technology Co Ltd
Current assignee: Jiangsu Kunzai New Material Technology Co Ltd
Priority date: 2019-09-23
Filing date: 2019-09-23
Publication date: 2019-12-24

Abstract

An adhesive-bearing optical connector includes a body (20) having a channel with a first portion (28) extending inwardly from a first face (22) of the body, a second portion (30) extending inwardly from a second face (24) of the body, and a transition portion (32) between the first portion (28) and the second portion (30). The first portion of the channel has a first width and the second portion of the channel has a second width that is less than the first width. A meltable adhesive composition (34) is located within the transition portion of the channel and is configured to bond the optical element. After the adhesive composition melts and solidifies, the fibers (54) reach the inner surface of the second portion.

Description

Optical connector with adhesive

Technical Field

The invention relates to the technical field of connectors, in particular to an optical connector with an adhesive.

Background

The present disclosure relates generally to fiber optic connectors, and more particularly to fiber optic connectors having an adhesive for coupling to an optical fiber. Optical fibers have found increasing use in various electronic and telecommunications fields. The optical fiber may be coupled to an optical connector (e.g., a ferrule). The connector allows coupling of the optical fiber to various devices, such as various electronic devices, other optical fibers, and the like.

Disclosure of Invention

One embodiment of the present disclosure is directed to an optical fiber connector pre-loaded with an adhesive. The optical fiber connector includes: a body having a first face and a second face; and a channel defined in the body, the channel extending between a first opening formed in the first face and a second opening formed in the second face. The channel is configured to receive an optical fiber. The channel includes a first channel portion extending inwardly from the first face and having a first width. The channel also includes a second channel portion extending inwardly from the second face and having a second width. The second width is less than the first width. The channel also includes a transition portion between the first channel portion and the second channel portion. The adhesive composition is located within the transition passage portion and is a solid material. The adhesive composition is configured to adhere the optical fiber to the inner surface of the second channel portion after the adhesive composition is melted and cured.

In some embodiments, the adhesive composition is located within the transition region, which blocks the interior inlet at the inner end of the second channel portion. The transition section may have a first end and a second end, wherein the inner end of the first channel section transitions to the first end of the transition section and the second end of the transition section transitions to the inner end of the second channel section.

In further embodiments, the first channel portion is a cylindrical bore extending from the first surface to the first end of the transition portion, and the first width is a first diameter. The second channel portion is a cylindrical bore extending from the second surface to a second end of the transition portion, and the second width is a second diameter. The first diameter is at least twice the second diameter. In addition, the axial length of the first channel portion is greater than half the axial length of the body, and the axial length of the second channel portion is greater than the axial length of the transition portion and less than one third of the axial length.

The transition portion in these and other embodiments may have a variable width that decreases with decreasing distance from the second face. For example, the transition portion may include a frustoconical inner surface, which may be located between the axial midpoint of the body and the second face.

Additionally, in these and other embodiments, the adhesive composition may be a solid powdered adhesive composition that is joined to the transition portion by compressing the solid powdered adhesive within the transition portion. For example, the adhesive composition may include a crosslinkable resin and a coupling agent, and in some embodiments, the coupling agent may be present in an amount of 0.1 to 10 parts by weight per 100 parts by weight of the crosslinkable resin.

Methods of forming optical fiber connectors such as the optical connectors described above are also provided. One such method involves providing a body and a channel of an optical fiber connector, placing an adhesive composition within a transition portion of the channel, and storing the optical fiber connector for at least one day after the placing step without coupling the optical fiber connector to the optical fiber connector.

In some embodiments, the method may further comprise preparing the binder composition as a solid powder. In such embodiments, placing the adhesive composition within the transition portion includes coupling the solid powder to a body within the transition portion by compression. The method may further comprise: heating the binder composition above the melting temperature of the binder composition, thereby rendering the solid powder flowable; inserting an optical fiber through the fiber-receiving channel; the body is cooled to cure the adhesive composition, thereby securing the optical fiber within the second channel portion.

Additional features and advantages will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments as described in the written description and claims hereof, as well as the appended drawings.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and are intended to provide an overview or framework for understanding the nature and character of the claims.

The accompanying drawings are included to provide a further understanding, and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiments and, together with the description, serve to explain the principles and operations of the various embodiments.

Drawings

FIG. 1 is a perspective view of an optical connector according to an exemplary embodiment;

FIG. 2 is a cross-sectional view of an optical connector according to an exemplary embodiment;

fig. 3 is a cross-sectional view similar to fig. 2. FIG. 2 illustrates a portion of an optical connector according to an exemplary embodiment, but shows a portion of the optical connector being heated;

fig. 4 is a cross-sectional view similar to fig. 3. FIG. 2 is the view of FIG. 2 but showing the insertion of an optical fiber into an optical connector, according to an exemplary embodiment;

FIG. 5 is a detailed view of the area encircled in FIG. 4;

FIG. 6 is a cross-section of an optical connector according to an exemplary embodiment;

fig. 7 is a perspective view of a multi-fiber optical connector according to an example embodiment.

Detailed Description

Referring generally to the drawings, various embodiments of an optical connector preloaded with an adhesive composition are shown. Typically, the optical connector includes a central fiber-receiving channel or through-hole (also referred to as a "ferrule hole") extending between a first end (e.g., a first face) and a second end (e.g., a second face). The fiber-receiving passage includes a large-diameter passage portion extending inwardly from the first surface and a small-diameter passage portion (also referred to as "micro-hole portion" or simply "micro-hole") extending inwardly from the second surface of the fiber bundle. A connector is provided. The micro-hole portion is sized to receive the optical fiber with a small amount of clearance between the outer surface of the optical fiber and the inner surface of the micro-hole.

A fusible, substantially solid adhesive composition is preloaded into the optical connector and retained primarily in the transition portion and/or the large diameter pass-through portion. When an optical connector is to be coupled to an optical fiber, heat may be focused on the optical connector at a location containing the pre-loaded adhesive composition, e.g., via one or more lasers, causing the adhesive composition to melt. As the adhesive melts, the optical fiber passes through the connector from the first side to the second side, and the optical fiber passes through the melted adhesive composition, drawing the melted adhesive into the micro-holes along with the optical fiber. The angle of the transition portion serves to guide the tip of the optical fiber into the micro-hole and also serves to leak the molten adhesive composition into the micro-hole. The large diameter of the large diameter channel portion and transition portion (as compared to the diameter of the micro-holes) provides sufficient space to store the adhesive composition within the connector's bore prior to heating.

As discussed in more detail below, the fusible adhesive composition loaded into the connector may be an adhesive that melts at a relatively high temperature (e.g., a temperature in excess of 290 degrees celsius) and quickly solidifies, hardens, or cures upon cooling. Because the adhesive compositions discussed herein cure rapidly after heating to bond the optical fibers within the connector, the optical connectors discussed herein can significantly increase the speed of coupling the optical fibers to the connector. The rapid curing of the adhesive located within the connector discussed herein may provide substantially increased yield during fiber optic connector attachment compared to typical fiber optic connector adhesives that require a relatively long time to cure to bond the optical fiber to the connector. The increased throughput also allows for a single piece to flow through the process of the fiber optic connector (rather than batch processing due to long adhesive cure times). Further, the meltable adhesive compositions discussed herein may each be a stable composition in solid, solid powder, or other stable form such that the adhesive composition may be used for extended periods of time (e.g., more than 1 day, more than one week, more than one year) before the adhesive composition is melted and coupled to the optical fiber. Thus, the optical connector and pre-loaded adhesive composition may eliminate the need to inject or otherwise place an adhesive into the optical connector immediately prior to fiber insertion. The meltable adhesive composition discussed herein may be a stable composition in solid, solid powder, or other stable form such that the adhesive composition may be used for extended periods of time (e.g., more than 1 day, one week, more than one year) before the adhesive composition is melted and coupled to the optical fiber. Thus, the optical connector and pre-loaded adhesive composition may eliminate the need to inject or otherwise place an adhesive into the optical connector immediately prior to fiber insertion. The meltable adhesive composition discussed herein may be a stable composition in solid, solid powder, or other stable form such that the adhesive composition may be used for extended periods of time (e.g., more than 1 day, one week, more than one year) before the adhesive composition is melted and coupled to the optical fiber. Thus, the optical connector and pre-loaded adhesive composition may eliminate the need to inject or otherwise place an adhesive into the optical connector immediately prior to fiber insertion. More than one year) and then the adhesive composition is melted and coupled to the optical fiber. Thus, the optical connector and pre-loaded adhesive composition may eliminate the need to inject or otherwise place an adhesive into the optical connector immediately prior to fiber insertion. More than one year) and then the adhesive composition is melted and coupled to the optical fiber. Thus, the optical connector and pre-loaded adhesive composition may eliminate the need to inject or otherwise place an adhesive into the optical connector immediately prior to fiber insertion.

Refer to fig. 2. Detailed description referring to fig. 1, a mechanical fiber optic connector assembly 10 is shown according to an exemplary embodiment. Generally, the connector assembly 10 includes a housing 12 and a crimp body 14. The fiber optic connector is located within housing 12 and is shown as ferrule 16. Generally, connector assembly 10 holds ferrule 16 during the various processing steps required to couple ferrule 16 to the ferrule.

Referring to fig. 2, a cross-sectional view of the connector assembly 10 is shown. The connector assembly 10 includes a ferrule holder 18 located within the housing 12. Ferrule holder 18 engages the outer surface of ferrule 16, thereby holding ferrule 16 in place.

As shown, ferrule 16 generally includes a body 20. In the illustrated embodiment, the body 20 is a generally cylindrical body that includes a first face 22 at a first end and a second face 24 at a second end. A fiber-receiving passage, shown as a central bore 26, extends through the body 20 and between the first face 22 and the second face 24. The central aperture 26 includes a first portion (shown as aperture portion 28), a second portion (shown as micro-apertures 30), typically, the diameter of the aperture portion 28 is greater than the diameter of the micro-apertures 30, and the diameter of the tapered portion 32 decreases as the distance from the second face 24 decreases (e.g., in a direction from left to right in the direction of fig. 2).

An adhesive composition or adhesive, shown as an adhesive plug 34, is located within central bore 26 of ferrule 16. As discussed in more detail below, the adhesive composition of the adhesive plug 34 is a meltable material configured to bond the optical fiber. The sealing plug 34 is a ferrule 16 within the micro-bore 30. In various embodiments, adhesive plug 34 is a substantially solid or solid powder that can be pre-loaded or stored within ferrule 16 for a significant period of time (e.g., one hour, one day, one year). Prior to coupling the fiber to the ferrule 16, and so on. In one such embodiment, the manufacturer of the ferrule may form the adhesive plug 34 within the ferrule 16.

As shown, adhesive plug 34 is located primarily within tapered portion 32 and the inner end of bore portion 28, and is positioned adjacent the entrance of tapered portion 32 to micro-bore 30. At normal processing or room temperatures (e.g., between about 15 ℃ and 30 ℃, less than 40 ℃, etc.), the adhesive plug 34 is substantially solid such that it extends between the opposing inner surfaces of the tapered portion 32. Substantially preventing access to the opening of micro-hole 30 from tapered portion 32.

Reference is generally made to fig. 1-4. Referring to fig. 3-5, the melting of the adhesive plug 34 and the coupling of the optical fiber to the ferrule 16 is shown according to an exemplary embodiment. Refer to the figures. Referring to fig. 3, in one embodiment, connector assembly 10 is configured for use in conjunction with a heating system that focuses heat onto ferrule 16 in the following manner: the adhesive plug 34 is melted without about one third of the first face 22 and/or the body 20. The temperature of the ferrule 16 adjacent the first face 22 reaches a temperature sufficient to damage the housing 12 and/or crimp body 14.

Refer to fig. 2. In fig. 3, ferrule 16 is shown supported by heating port 40. Heating port 40 includes an opening 42, and when supported within heating port 40, second face 24 of ferrule 16 extends through opening 42. The heating port 40 includes a reflector 44 surrounding the opening 42. The reflector 44 includes an angled reflective surface positioned relative to the ferrule 16 to focus heat onto a portion of the ferrule 16 to melt the adhesive plug 34. In one embodiment, heating may be achieved by focusing the CO2 laser beam 46 at about the front. One third of ferrule 16 (i.e., the third adjacent second face 24 of ferrule 16) passes through reflector 44.

In various embodiments, heat is focused on the portion of ferrule 16 that includes adhesive plug 34 and micro-hole 30, causing adhesive plug 34 to melt while limiting heating of other areas of ferrule 16. In one embodiment, during heating, the portion of ferrule 16 including adhesive plug 34 is heated above 290 ℃ while the temperature of first face 22 of ferrule 16 is maintained below 250 ℃. In another embodiment, during heating, the portion of ferrule 16 including adhesive plug 34 is heated above 350 ℃ while the temperature of first face 22 of ferrule 16 is maintained below 250 ℃. In another embodiment, during heating, the portion of ferrule 16 including adhesive plug 34 is heated above 400 ℃ while the temperature of first face 22 of ferrule 16 is maintained below 250 ℃. In another embodiment, the portion of ferrule 16 that includes sealing plug 34 is heated above 350 ℃ while the temperature of first face 22 of ferrule 16 remains below 200 ℃ during heating.

In one embodiment, during heating, the portion of ferrule 16 including adhesive plug 34 is heated to between 400 and 600 ℃ while the temperature of first face 22 of ferrule 16 is maintained below 250 ℃.

In one embodiment, housing 12 includes a clamping member 50, and in such an embodiment, ferrule 16 includes an interior 52 located within housing 12 inward from clamping member 50. As shown in fig. 3, inner portion 52 of ferrule 16 is the portion of ferrule 16 to the left of clamping member 50. In such embodiments, during heating and melting of adhesive 34, inner portion 52 of ferrule 16 is maintained at a temperature below that which would damage the housing. 12. In one such embodiment, the portion of ferrule 16 that includes adhesive plug 34 is heated above 290 ℃ while the temperature of interior 52 of ferrule 16 is maintained below 250 ℃. In another embodiment, the portion of ferrule 16 that includes adhesive plug 34 is heated above 290 ℃ while the temperature of interior 52 of ferrule 16 is maintained below 200 ℃. In another embodiment, the portion of ferrule 16 that includes adhesive plug 34 is heated above 350 ℃ while the temperature of interior 52 of ferrule 16 is maintained below 200 ℃. In another embodiment, the portion of ferrule 16 including adhesive plug 34 is heated to between 400 and 600 ℃ while the temperature of interior 52 of ferrule 16 is maintained below 200 ℃.

The larger diameter of bore portion 28 (as compared to the smaller diameter of micro-bores 30) results in a majority of the volume of ferrule 16 being filled with air, and the air in ferrule 16 may act as a buffer as described above, and the insulating effect of the air within bore portion 28 may help maintain interior 52 of sleeve 16 at a low temperature during heating, as described above. It should be understood that the temperature to which the portion of ferrule 16 including the adhesive composition is heated will be based on the melting temperature of the particular adhesive composition located within ferrule 16.

Refer to fig. 2. Refer to fig. 4 and 3. As shown in fig. 5, once the plug 34 is heated above its melting temperature (e.g., 290 ℃, 350 ℃, 400 ℃, etc.), the adhesive composition becomes flowable, allowing the optical fiber 54 to be inserted into the central bore 26. As shown, the optical fibers 54 are inserted into the bore 26 in a direction from the first face 22 toward the second face 24. The optical fiber 54 passes through the larger diameter bore portion 28 and then encounters the flowable adhesive material 56 (i.e., the molten material 56). The plug 34). The optical fiber 54 passes through the tapered portion 32 and into the micro-hole 30. Tapered portion 32 serves to leak or direct molten adhesive composition 56 into micro-holes 30, and the viscosity of molten adhesive composition 56 allows optical fiber 54 to pull out of adhesive 56. Into micro-holes 30. Thus, as optical fiber 54 passes through micro-hole 30, a thin layer of adhesive 58 surrounds the outer surface of optical fiber 54 and fills the space between optical fiber 54 and the inner surface of micro-hole 30. Fiber 54 is then placed in position, ferrule 16 is cooled, the molten adhesive is allowed to solidify, and fiber 54 is bonded in place within micro-hole 30. After the adhesive composition is cured, other steps to complete the connector (e.g., polishing the optical fibers 54 on the second side 24) may be performed. In some embodiments, ferrule 16 may be actively cooled, such as by blowing, to speed up the cooling and curing process. In other embodiments, ferrule 16 may be passively cooled,

refer to fig. 2. Referring to fig. 6, a detailed view of ferrule 16 including adhesive plug 34 is shown, according to an exemplary embodiment. As described above, ferrule 16 includes a central bore 26 extending from first face 22 to second face 24. In the illustrated embodiment, first face 22 and second face 24 each define a plane at respective first and second ends of ferrule 16, and the planes are substantially parallel to each other. However, in other embodiments, the first face 22 and/or the second face 24 may define planes that are positioned at an angle relative to one another (i.e., non-parallel planes). In other embodiments, first face 22 and/or second face 24 may not be planar surfaces, and may be convex or concave, for example.

The central bore 26 includes a larger diameter bore portion 28 extending from the first face 22 to an inner end 60. An inner end 60 of the bore portion 28 transitions to a first end 62 of the tapered portion 32. A tapered portion 32 extends from the first end. In fig. 6, bore 62 transitions to a second end 64 of tapered portion 32, second end 64 transitioning to an inner end 66 of micro-bore 30. The micro-holes 30 extend from the inner end 66 to the second face 24. Thus, in this manner, bore section 28, micro-bores 30 and tapered portion 32 define a continuous fiber-receiving channel extending from first face 22 to second face 24.

In various embodiments, the structural arrangement, positioning and relative dimensions of ferrule 16, and in particular portions of central bore 26, provide a ferrule having the various functional characteristics described herein. In the illustrated embodiment, ferrule 16 is generally cylindrical with an outer diameter of outer surface 70 shown as D1, and bore section 28 and micro bore 30 are cylindrical or generally cylindrical bores each having a constant or substantially constant diameter along its length. In fig. 6, the inner diameter of hole portion 28 is denoted as D2, and the inner diameter of micro-hole 30 is denoted as D3. It should be understood that in other embodiments, outer surface 70, bore segment 28, and micro-bore 30 may have a non-circular cross-sectional shape.

In various embodiments, the diameter D2 of the bore portion 28 may be sized to allow for easy or efficient insertion of adhesive material into the ferrule 16 to form the adhesive plug 34. In addition, as described above, the large diameter D2 relative to the outer portion, diameter D1, provides a large internal cavity that retains air during heating of the ferrule 16, which air may act as a buffer or insulator limiting heating of the interior 52 of the ferrule 16. In addition, D3 is sized to closely match the outer diameter of fibers 54, leaving sufficient space for the adhesive to bond fibers 54 within micropores 30.

In various embodiments, D2 may be between 20% and 80% of D1, or specifically between 20% and 60% of D1, or even more specifically between 30% and 50% of D1. In a specific embodiment, D2 is about 40% of D1. Additionally, in various embodiments, D2 may be greater than twice D3, or specifically greater than four times D3, and even more specifically between 7 and 9 times D3. In a particular embodiment, D3 is between 0.1255mm and 0.1260 mm. In one embodiment, D2 is between.250 mm and 1.0mm, and in another embodiment, D2 is between.500 mm and 1.0 mm. In a particular embodiment, D1 is about 2.5mm, D2 is about 1mm, and D3 is about 0.1255 mm. In another particular embodiment, D1 is about 1.25mm and D3 is about 0.1255 mm.

The diameter of the tapered portion 32 decreases from left to right in the direction of fig. 2. As shown in fig. 6 (e.g., the diameter of tapered portion 32 decreases as the distance to second face 24 decreases), and the decrease in diameter of tapered portion 32 provides a transition from D2 to D3. In the illustrated embodiment, tapered portion 32 is a generally frustoconical portion having an inner surface 72 positioned at an angle a relative to a longitudinal axis 74 of ferrule 16. In various embodiments, the angle a may be between 30 ° and 80 °, in particular between 50 ° and 70 °, even more particularly about 60 °.

Although illustrated in the figures. Fig. 6 shows the transition portion of the central bore 26 as a frustoconical tapered portion 32 having a diameter proportional (e.g., linearly related) to the distance from the second face 24. In other embodiments, the inner surface 72 may have other shapes that generally have the following shapes: the variable width/diameter decreases with decreasing distance to the second face 24. For example, the surface 72 may include a step of decreasing diameter, or may be a surface having a continuously curved but non-linear relationship with distance to the second face 24. As described above, the reduced diameter of tapered portion 32 serves to leak molten adhesive into micro-holes 30 and also serves to guide fibers 54 into micro-holes 30 for insertion during the process.

In addition, the relative lengths of ferrule 16, bore portion 28, micro-bore 30, and tapered portion 32 may further contribute to the functionality discussed herein. For example, the relative lengths are configured to allow placement of adhesive plugs 34 adjacent to micro-wells 30. As described above, this placement may allow the ferrule to be heated to melt the adhesive plug 34 while limiting heating of the interior of the ferrule head 16.

As shown, ferrule 16 has an axial length L1, bore portion 28 has an axial length L2, tapered portion 32 has an axial length L3, and micro-bore 30 has an axial length L4. In the embodiment shown, L2 is greater than L3 and L4, and L4 is greater than L3. In various embodiments, L2 may be greater than 50% of LI, greater than 55% of LI, or from about 60% of LI. L2 may be, for example, between 50% and 70% of LI. In various embodiments, L4 may be less than 40% of LI, less than one-third of LI, or even less than 30% of LI. L4 may be, for example, between 20% and 40% of LI. In various embodiments, L3 may be less than 30% of LI, less than 20% of LI, or from anywhere to less than 10% of LI. L3 may be, for example, 5% to 15% of LI.

In the illustrated embodiment, the adhesive plug 34 is located primarily within the tapered portion 32 and bore portion 28, near the inner end 60 thereof. In the illustrated embodiment, a small portion of the adhesive plug 34 may extend into the micro-hole 30 such that the material of the plug 34 substantially blocks the opening between the tapered portion 32 and the micro-hole 30 before the adhesive material melts.

In the illustrated embodiment, all of the adhesive plug 34 is located in the central bore 26 between the axial midpoint 76 and the second face 24. In various embodiments, at least 80% or at least 90% or even further, at least 95% of the adhesive plug 34 may be located between the axial midpoint 76 and the second end 64 of the tapered portion 32 prior to melting the plug 34. In various embodiments, greater than 50% of the adhesive plug 34 may be located within the tapered portion 32. In various embodiments, the mass of the adhesive plug 34 may be between 0.5mg and 5mg, or between 0.5mg and 3mg, or even more specifically between 1mg and 2 mg. In a particular embodiment, the mass of the adhesive plug 34 may be about 1.2 mg.

In some embodiments, tapered portion 32 and aperture portion 28 provide a storage area for the adhesive material prior to heating and flowing into micropores 30. In some such embodiments, the adhesive material of adhesive plug 34 may include the manufacture of adhesive material with particles or pellets having an average diameter sufficiently larger than the diameter of micro-pores 30 such that it is not practical to place the adhesive material into micro-pores 30 prior to melting. For example, in certain embodiments, the average diameter of the adhesive particulate of the adhesive plug 34 may be greater than 25% of D3, greater than 50% of D3, or greater than 75% of D3.

In general, the adhesive plug 34 may be formed from a variety of meltable adhesive compositions. In some embodiments, the adhesive plug 34 may be formed from a meltable adhesive having a relatively high melting point (e.g., in excess of 290 ℃). In such embodiments, the high melting temperature corresponds to an adhesive that cures relatively quickly (e.g., in less than 30 seconds, less than 20 seconds, less than 15 seconds) upon cessation of heating. The lower cooling/setting time enables the optical fiber to be coupled to the ferrule 16 relatively quickly compared to ferrules coupled using conventional epoxies, which may require curing times as long as 20-30 minutes. Additionally, in various embodiments, the adhesive composition of ferrule 16 may be partially cross-linkable such that the adhesive partially cross-links, melts, and solidifies upon heating. Such partially crosslinked adhesive will resist re-melting if the ferrule/fiber assembly reaches the melting temperature of the adhesive during use. Various embodiments of the adhesive compositions disclosed herein may also have other desirable properties for the process of securing the optical fiber within the ferrule, such as, but not limited to, reduced process cycle time, no need for mixing, and/or no pot life issues.

In various embodiments, the adhesive plug 34 may be loaded into the ferrule 16 at a time and/or location that is distant from the time and location of the fiber attachment. In one embodiment, the adhesive plug 34 may be loaded into the ferrule 16 at a first physical location or facility (e.g., a ferrule manufacturing facility), and the ferrule 16 loaded with adhesive may then be transported to a second physical location or facility where the ferrule is coupled. 16 to optical fiber. Thus, the plug 34 may be coupled within the tapered portion 32 in various ways such that the plug 34 remains within the collar 16 during handling, shipping, packaging, etc. of the collar 16.

In one embodiment, the adhesive plug 34 is a solid powdered adhesive composition that is coupled within the tapered portion 32 by compression of the powdered adhesive before being heated or otherwise cured. In another embodiment, the adhesive material is extruded or injection molded into the tapered portion 32 to form the adhesive plug 34, and in such an embodiment, the adhesive material may comprise a thermoplastic material. Thus, the ferrules discussed herein may contain adhesive material for extended periods of time, e.g., 8 hours, 16 hours, 1 day, 1 week, 1 month, 6 months, 1 year, before heating to bond the optical fibers within the ferrule.

As used herein, an "adhesive" (or "adhesive material" or "adhesive composition") is a substance that is capable of holding materials together by surface attachment. In an embodiment, the adhesive composition of the adhesive plug 34 may generally include a partially crosslinked resin and a coupling agent. In some embodiments, the coupling agent may be present in an amount of about 0.1 to about 10 parts by weight per 100 parts by weight of the partially crosslinked resin. In various embodiments, about 0.1, about 0.5, about 1, about 2, about 4, about 6, about 8, or about 10 parts by weight of the coupling agent may be present per 100 parts by weight of the partially crosslinked resin. Or any combination of the foregoing weight ratios.

As used herein, a "thermoplastic resin" is a material that includes a polymeric material that will repeatedly soften when heated and harden when cooled without cross-linking of the polymer chains. For example, the thermoplastic resin may be repeatedly softened and hardened by a heating and cooling cycle. As used herein, "cross-linking" or "cross-linking" refers to a chemical bond that connects a polymer chain to an adjacent polymer chain, and "cross-linkable" describes a chemical species that becomes at least partially cross-linked when: sufficient heat is applied. As used herein, "partially cross-linked" or "partially cross-linked" refers to chemical bonding that connects a polymer chain to an adjacent polymer chain, wherein not all adjacent chains are bonded, as opposed to thermoplastic and thermoset resins; "partially crosslinkable" describes a chemical species that becomes partially crosslinked upon the application of sufficient heat. It should be understood that when the terms "partially crosslinked" and "partially crosslinkable" are used to describe the polymers of the adhesive compositions described herein, the same resins are described at a particular time before or after crosslinking.

For example, the resin may be described as being partially cross-linkable when the resin is filled into the ferrule and has not been heated to be partially cross-linked. After heating, the resin may be partially crosslinked. In another embodiment, the resin may be crosslinked immediately prior to insertion of the optical fiber prior to the heating step, for example if the adhesive composition is injection molded prior to placement into the ferrule. However, since crosslinking may occur in a heating step immediately prior to the insertion of the optical fiber, the injection molding adhesive composition may still be described as being partially crosslinkable.

It should also be understood that when an adhesive composition is described herein, if it is said that the adhesive composition comprises a partially cross-linked resin, then this is equivalent to said that the adhesive composition comprises a partially cross-linkable resin prior to the cross-linking. And a linking step. While cross-linking can provide permanence to hold structures firmly together during connector assembly, and thermoplastic resins can flow materials in a controlled manner for ferrule fabrication, partially cross-linked materials can uniquely and synergistically take advantage of both materials.

In one embodiment, the adhesive composition may have the following properties: at least about 5 weight percent of the resin is crosslinked or crosslinkable, and at least about 5 weight percent of the resin is uncrosslinked or crosslinkable. In another embodiment, the adhesive composition may have the following properties: at least about 10 weight percent of the resin is crosslinkable or crosslinkable, and at least about 10 weight percent of the resin is non-crosslinkable or crosslinkable. . In another embodiment, the adhesive composition may have the following properties: at least about 20 weight percent of the resin is crosslinked or crosslinkable, and at least about 20 weight percent of the resin is uncrosslinked or crosslinked.

In some embodiments, the partially crosslinked resin material may have a melting point at a temperature of at least about 250 ℃, 270 ℃, or 290 ℃. In some embodiments, the partially crosslinked resinous material may be crosslinked in the presence of air at a temperature of at least about 300 ℃, 325 ℃, or 350 ℃. Additionally, the partially crosslinked resin may be capable of bonding in less than about 5 minutes, 3 minutes, 1 minute, 30 seconds, or anywhere from 15 seconds. In contemplated embodiments, the partially crosslinked resin need not be mixed, not degassed and/or not have pot life issues. In one embodiment, the adhesive composition may comprise one or more partially crosslinked resins, such as, but not limited to, partially crosslinked polyphenylene sulfide.

In other embodiments, the adhesive composition may comprise one or more partially or non-partially crosslinked resins such as, but not limited to, polyphenylene ether, polyamide-imide, liquid crystal polymers, polyetheretherketone, cyclic olefin copolymers, or combinations thereof. For example, polyphenylene sulfide may include, but is not limited to, VI available from Chevrolet Philips Chemicals LLC of Wolland, Tex, or 0205P4 or 0203P6 available from Ticona GmbH of Frankfurt. Germany. Polyphenylene ethers may include, but are not limited to, SabicSA-102, available from SABIC of saudi arabia. The liquid crystalline polymer may include a950VF300I available from Ticona of florfenisa.

The polyetheretherketone may comprise KT-85I available from Suwei of Brussel, Belgium. The cyclic olefin copolymer may comprise TOPAS5013L-10 from Topas advanced polymers.

The coupling agent may comprise a plurality of one or more suitable coupling agents. In one embodiment, the coupling agent may comprise an epoxy, amino or mercapto functional silane. The silane groups on the coupling agent may include alkoxy silanes, oxime silanes, acetoxy silanes. Alternatively, or in combination with the silane coupling agents described above, the coupling agents may comprise zirconates, titanates, or combinations thereof. In one embodiment, the coupling agent may comprise

Glycidoxypropyltrimethoxysilane, such as gamma-glycidoxypropyltrimethoxysilane. For example, coupling agents may include A-I87 available from Crompton Corp. of CT, Middlebury, AlquestAl100, or Kenrichpetrochemicals, Inc, of Bayonne, N.J.. Ken-ReactKR 55.

The combination of the coupling agent and the partially crosslinked resin may result in enhanced adhesive strength. In particular, the coupling agent may provide chemical coupling between: a) inorganic surfaces of optical fibers and/or ferrules, and b) a polymer matrix of an adhesive. After cooling, the partially crosslinked resin, which may have no functional groups that can react with the inorganic surface, may be covalently bonded to one or both of the optical fiber or the ferrule by a coupling agent. The coupling agent may comprise functional groups specifically capable of covalently bonding to the inorganic material, and groups specifically capable of reacting with organic functional groups. The organofunctional groups on the coupling agent may include epoxy, amino, mercapto, acrylate or any other organofunctional group. In one embodiment, the functional group on the coupling agent that reacts with the inorganic material may be an alkoxysilane. Other possible groups include oxime silanes or acetoxy silanes. In addition to silane coupling agents, zirconates and titanates have also been shown to have this coupling capability.

The adhesive compositions described herein may further comprise at least one thermosetting resin. A variety of thermosetting resin materials can be used as components of the adhesive composition. As used herein, a "thermosetting resin" is a material that includes at least one polymeric material that will chemically react by or through the action of heat, catalysts, ultraviolet light, and the like, resulting in a relatively insoluble state.

Examples of suitable thermosetting resins may include, but are not limited to, epoxy resins, such as bisphenol a based epoxy resins or epoxy novolacs. In one embodiment, about 1 to about 85 parts by weight of the thermosetting resin may be present per 100 parts by weight of the partially crosslinked resin. In various embodiments, about 1, about 5, about 10, about 30, about 50, about 70, about 80, or about 85 parts by weight of the thermosetting resin may be present per 100 parts by weight of the partially crosslinked resin. Or any combination of the foregoing weight ratios.

The combination of a thermosetting resin and a partially crosslinked resin may result in enhanced adhesive strength. In particular, after curing at temperatures above 300 ℃, the binder may form a homogeneous system of thermoplastic and a crosslinked network structure throughout the matrix. The crosslinked structure may be formed not only of a thermosetting material but also between a thermoplastic and a thermosetting material. For example, a partially crosslinked thermoplastic resin may react with a thermosetting resin at elevated temperatures through phenolic groups at the ends of the polymer chains. The formed network structure may improve the integrity of the adhesive and corresponding fiber optic connector to resist environmental aging and creep under shear stress and improve bond strength on the substrate.

In one embodiment, the adhesive composition may further comprise a curing agent. If the adhesive composition includes such a thermosetting resin, the curing agent may help to cure the thermosetting resin, such as an epoxy resin, and/or may help to cure the coupling agent. For example, the curing agent may react with the coupling agent and/or the epoxy group of the thermosetting resin. The curing agent may include one or more useful curing agents such as, but not limited to, anhydride curing agents, amide curing agents, aromatic amine curing agents, dianhydrides, monoanhydrides, guanidine compounds, amine curing agents, or combinations thereof. For example, the curing agent may include dicyandiamide, pyromellitic dianhydride, dodecylsuccinic anhydride, oolong ketone, urea, melamine, dicyandiamide, or a combination thereof. In one embodiment, the adhesive composition further comprises about 0.2 to about 50 parts by weight of a curing agent per 100 parts by weight of the coupling agent. In various embodiments, the curing agent may be present in an amount of about 0.2, about 0.5, about 1, about 5, about 10, about 20, about 30, about 40, or about 50 parts by weight per 100 parts by weight of the coupling agent. Or any combination of the foregoing weight ratios. In another embodiment, the adhesive composition further comprises about 0.2 to about 50 parts by weight of a curing agent per 100 parts by weight of the thermosetting resin. In various embodiments, the curing agent may be present in an amount of about 0.2, about 0.5, about 1, about 5, about 10, about 20, about 30, about 40, or about 50 parts by weight per 100 parts by weight of the thermosetting resin. Or ranges between any combination of the foregoing weight ratios. In yet another embodiment, the adhesive composition further comprises from about 0.2 to about 100 parts by weight of a curing agent per 100 parts by weight of the sum of the weight of the thermosetting resin and the weight of the coupling agent. In various embodiments, about 0.2, about 0.5, about 1, about 5, about 10, about 30, about 50, about 70, about 90, or about 100 parts by weight of curing agent may be present per 100 parts by weight of curing agent. The sum of the weight of the thermosetting resin and the weight of the coupling agent, or any combination of the above weight ratios. From 2 to about 100 parts by weight of a curing agent per 100 parts by weight of the thermosetting resin plus the weight of the coupling agent. In various embodiments, about 0.2, about 0.5, about 1, about 5, about 10, about 30, about 50, about 70, about 90, or about 100 parts by weight of curing agent may be present per 100 parts by weight of curing agent. The sum of the weight of the thermosetting resin and the weight of the coupling agent, or any combination of the above weight ratios. From 2 to about 100 parts by weight of a curing agent per 100 parts by weight of the thermosetting resin plus the weight of the coupling agent. In various embodiments, about 0.2, about 0.5, about 1, about 5, about 10, about 30, about 50, about 70, about 90, or about 100 parts by weight of curing agent may be present per 100 parts by weight of curing agent. The sum of the weight of the thermosetting resin and the weight of the coupling agent, or any combination of the above weight ratios.

In one embodiment, the adhesive composition may further comprise one or more filler materials. The filler material may be a mineral component, such as pyrophosphate of at least one metal. For example, the metal may comprise cobalt or magnesium, such that the filler material is magnesium pyrophosphate, cobalt pyrophosphate, or a combination thereof. In one embodiment, the adhesive composition further comprises from about 0.5 to about 85 parts by weight of a filler material per 100 parts by weight of the partially crosslinked resin. In various embodiments, about 0.5, about 1, about 5, about 10, about 30, about 50, about 70, about 80, or about 85 parts by weight of filler material may be present per 100 parts by weight of thermosetting resin.

In one embodiment, the filler material may comprise a material having a negative coefficient of thermal expansion. As used herein, a material having a negative coefficient of thermal expansion refers to a material that undergoes a phase transition and concomitant volume reduction at a temperature of, for example, about 50 ℃, about 30 ℃, about 20 ℃. The crosslinked resin has a glass transition temperature of about 0 ℃ or about 10 ℃. Materials containing negative coefficients of thermal expansion can help to maintain the density of the adhesive composition upon heating, thereby maintaining its volume so that it does not expand and apply excessive pressure to the ferrule in some cases. Resulting in cracking or breaking of the ferrule.

It should be understood that the various components of the adhesive composition embodiments disclosed herein may be combined in any combination in any ratio disclosed herein. Such various components include partially crosslinked thermoplastic resins, coupling agents, thermosetting resins, curing agents and filler materials. Further, while the desired properties of the adhesive composition may result from a combination of only two or more of the various components, any combination of components is contemplated.

It should be further understood that in some embodiments, when a component of the adhesive composition is referred to, it may be an optional component, and in all embodiments, it is not necessarily required that it be an optional component in the adhesive composition.

For example, in one embodiment, the adhesive composition may comprise a partially crosslinked resin, a coupling agent, a curing agent, and a partially crosslinked resin. The adhesive composition may comprise about 0.1 to about 10 parts by weight of the coupling agent per 100 parts by weight of the partially crosslinked resin and about 0.2 to about 5 parts by weight of the curing agent per 100 parts by weight of the acrylate composition. About 0.5 to about 85 parts by weight of a filler material per 100 parts by weight of the partially crosslinked resin.

In some embodiments, the binder composition may be prepared as a solid powder. At least some of the various components of the binder composition may be solid and may be ground into a powder, such as any or all of a partially or fully crosslinked resin, a thermosetting resin, a curing agent, and/or a filler material. . The solid powder materials should be thoroughly mixed. In one embodiment, the coupling agent may be a liquid. However, the proportion of coupling agent in the blend may be relatively small, so that the coupling agent may be combined with one of the solid components of the adhesive composition, and the resulting blend may be a free-flowing powder. For example, in one embodiment, the coupling agent may be pre-reacted with the thermoplastic powder in an organic solvent under reflux conditions. After removal of the solvent, the treated powder was still present. Under conditions of refluxing solvent, some of the coupling agent may already be permanently bonded to the polymer. Additional embodiments of adhesive compositions that can be used to form the adhesive plug 34 and/or used in conjunction with the optical connectors discussed herein are disclosed in detail in U.S. patent No.8,696,215, which is incorporated herein by reference in its entirety.

It should be understood that while fig. 1 and 2 depict adhesive-loaded ferrules configured to be coupled to a single optical fiber, the adhesive composition, the ferrule central bore configuration, and the configuration of the adhesive plug 34 may be used in a variety of fiber optic connector applications. For example, the multi-fiber connector 100 as shown in fig. 1 may include a plurality of connectors 100. According to various embodiments discussed herein, the embodiment of fig. 7 may include a plurality of central bores 26 and a plurality of viscous plugs 34. The principles discussed herein may also be used with mechanical splice fiber optic connectors. Examples of various single fiber mechanical splice connectors are provided in U.S. patent No.5,200,300. 4,755,018 No. C; 4923274, 5040867, and 5,394,496. Examples of various multi-fiber mechanical splice connectors are provided in U.S. patent No.5,200,300. 6,173,097 No. C; 6379054, 6,439, 780, and 6,816,661.

In various embodiments, a method of forming an optical connector preloaded in an adhesive composition is provided. The method includes providing an optical connector, and the optical connector includes: a body having a first face and a second face; and a fiber-receiving channel defined in the body, the fiber-receiving channel extending between a first opening formed on the first face and a second opening formed. On the second face. The fiber-receiving channel includes a first channel portion extending inwardly from the first face and having a first diameter. The fiber-receiving channel includes a second channel portion extending inwardly from the second face and having a second diameter. The second diameter is smaller than the first diameter. The fiber-receiving channel includes a tapered channel portion having a variable diameter between the first channel portion and the second channel portion, and the variable diameter of the tapered portion decreases as the distance to the second face decreases. The method includes placing an adhesive composition within the tapered channel portion and storing the optical connector for at least one day after the placing step without coupling the optical connector to the optical fiber. In various embodiments, the method may include coupling an adhesive composition to an inner surface of the body at the tapered channel portion. In various embodiments, the coupling step includes curing the adhesive composition within the tapered channel portion after the adhesive composition is placed. In various embodiments of the present invention, the,

the optical fibers discussed herein may be flexible transparent optical fibers made of glass or plastic. The fiber may be used as a waveguide to transmit light between the two ends of the optical fiber. The optical fiber may include a transparent core surrounded by a transparent cladding material having a lower refractive index. Light may remain in the core by total internal reflection. Glass fibers may comprise silica, but other materials may be used, such as fluorozirconates, fluoroaluminates, and chalcogenide glasses, as well as crystalline materials, such as sapphire. Light may be directed down the core of the fiber by an optical cladding with a lower refractive index that traps the light in the core by total internal reflection. The coating may be covered with a buffer and/or other coating that protects it from moisture and/or physical damage. These coatings may be UV cured urethane acrylate composites that are applied to the exterior of the optical fiber during the drawing process. The coating may protect the glass fiber strands. The optical fiber may include an inner primary coating and an outer primary coating. The optical fiber coating may be applied in concentric layers.

The optical connectors discussed herein may generally include ceramic materials such as, but not limited to, zirconia, alumina, titanium doped alumina, glass filled PPS, or combinations thereof. However, other materials of construction of the ferrule are contemplated herein, such as metals, ceramics, polymers, or combinations thereof.

Unless explicitly stated otherwise, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Thus, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is no way intended that any particular method be so recited. The order may be inferred.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Since modifications combinations, sub-combinations and variations of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and their equivalents.

Claims

1. An optical fiber connector comprising: a body having a first face and a second face; a channel defined in the body, the channel extending between a first opening formed on the first surface and a second opening formed on the second surface, the channel configured to receive an optical fiber, the channel comprising: a first channel portion extending inwardly from the first face and having a first width; a second channel segment extending inwardly from the second face and having a second width, wherein the second width is less than the first width, and a transition portion located between the first channel portion and the second channel portion; and an adhesive composition located within the transition portion, wherein the adhesive composition is a solid material and is configured to bond the optical fiber to the inner surface of the second channel portion after the adhesive composition melts and cures.

2. The fiber optic connector of claim 1, wherein the adhesive composition is located within the transition region, blocking an interior entrance at an inner end of the second channel portion.

3. The fiber optic connector of claim 2, wherein the transition portion has a first end and a second end, wherein the inner end of the first channel portion transitions into the first end of the transition portion and the second end of the transition portion transitions into the inner end of the second channel portion.

4. The fiber optic connector of claim 3, wherein: the first channel portion is a cylindrical bore extending from a first face of the transition portion to a first end, the first width being a first diameter, the second channel portion is a cylindrical bore extending from the second surface to a second end of the transition portion, the second width being a second diameter, the first diameter being at least twice the second diameter; the axial length of the first channel portion is greater than half the axial length of the body, and the axial length of the second channel portion is greater than the axial length of the transition portion and less than one third of the axial length of the body.

5. The fiber optic connector of claim 4, wherein the body has an outer diameter and the first diameter is greater than 30% of the outer diameter of the body.

6. The fiber optic connector of any of claims 3-5, wherein at least 95% of the adhesive composition is located between the axial midpoint of the body and the second end of the transition portion.

7. The fiber optic connector of any of claims 1-6, wherein the transition portion has a variable width that decreases with decreasing distance from the second face.

8. The fiber optic connector of claim 7, wherein the transition portion includes a frustoconical inner surface.

9. The fiber optic connector of claim 8, wherein the frustoconical inner surface is angled between 30 ° and 80 ° relative to a longitudinal axis of the body, wherein the frustoconical inner surface extends from the first end to the first end of the transition portion.

10. The fiber optic connector of claims 8 or 9, wherein the frustoconical inner surface is located between an axial midpoint of the body and the second face.