WO2023028161A1

WO2023028161A1 - Methods and systems for filling a fiber optic connector with epoxy

Info

Publication number: WO2023028161A1
Application number: PCT/US2022/041399
Authority: WO
Inventors: Samuel Taylor FINNEGAN
Original assignee: Commscope Technologies Llc
Priority date: 2021-08-26
Filing date: 2022-08-24
Publication date: 2023-03-02

Abstract

Methods and systems for filling a fiber optic connector with epoxy. A ferrule assembly has a ferrule and a ferrule hub with an inner passageway configured to receive epoxy. A capacitance meter is positioned relative to the ferrule assembly while epoxy is injected into the inner passageway of the ferrule assembly. Capacitance within the ferrule assembly is measured via the capacitance meter while epoxy is being injected into the inner passageway of the ferrule assembly. Based on the measured capacitance within the ferrule assembly, epoxy is stopped from being injected into the inner passageway of the ferrule assembly.

Description

METHODS AND SYSTEMS FOR FILLING A FIBER OPTIC CONNECTOR WITH EPOXY

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is being filed on August 24, 2022 as a PCT International Patent Application and claims the benefit of U.S. Patent Application Serial No. 63/260,586, filed on August 26, 2021, the disclosure of which is incorporated herein by reference.

BACKGROUND

[0002] During fiber optic connector manufacturing, epoxy is typically deposited inside a ferrule assembly before a fiber optic cable is inserted into the connector. The fiber optic connector can include a ferrule, and the fiber optic cable includes an outer coating and an inner light transmitting portion having a glass core and a glass cladding layer around the core that is secured within the ferrule.

[0003] The epoxy is often dispensed by a syringe having a needle that is inserted down into the ferrule assembly adjacent to an inner passageway through the ferrule. The syringe and needle are then retracted, and the fiber optic cable is inserted into the connector, with a portion of the outer coating being removed, exposing the glass cladding layer that is inserted down into the ferrule. The epoxy holds the glass cladding layer in position within the ferrule once the epoxy is cured, such as by using heat, ultraviolet light, etc.

[0004] During manufacture of fiber optic connectors, it is desirable that the epoxy be properly dispensed. Too much epoxy can cause problems; so can an insufficient amount of epoxy.

SUMMARY

[0005] Aspects of the present disclosure relate to methods and systems that are used in the manufacture and assembly of fiber optic connectors. In certain aspects, the methods and systems are used for dispensing epoxy within components of the fiber optic connector so as to increase assembly efficiencies during the fiber optic connector manufacturing process. [0006] In an aspect, the technology relates to a method of filling a fiber optic connector with epoxy, the method including: providing a ferrule assembly including a ferrule and a ferrule hub, the ferrule assembly having an inner passageway configured to receive epoxy; positioning a capacitance meter relative to the ferrule assembly; injecting epoxy into the inner passageway of the ferrule assembly; measuring capacitance within the ferrule assembly via the capacitance meter while epoxy is injected into the inner passageway of the ferrule assembly; and based on the measured capacitance within the ferrule assembly, stopping epoxy being injected into the inner passageway of the ferrule assembly.

[0007] In an example, positioning the capacitance meter relative to the ferrule assembly includes: positioning a first electrode relative to the ferrule; and positioning a second electrode relative to the ferrule hub. In another example, positioning the second electrode relative to the ferrule hub includes coupling the second electrode to a needle that injects epoxy into the inner passageway of the ferrule assembly. In yet another example, positioning the first electrode relative to the ferrule includes coupling the first electrode to a probe positioned relative to the ferrule. In still another example, positioning the first electrode relative to the ferrule includes inserting at least a portion of the probe into the inner passageway of the ferrule assembly. In an example, the method further includes adjusting a distance that a distal end of the probe is inserted into the inner passageway of the ferrule assembly.

[0008] In another example, the method further includes removing the probe from the inner passageway of the ferrule assembly and cleaning epoxy from the probe. In yet another example, the method further includes removing the probe from the inner passageway of the ferrule assembly and replacing the probe based at least partially on its curvature. In still another example, measuring capacitance within the ferrule assembly includes comparing a capacitance value within the inner passageway of the ferrule assembly when empty with a capacitance value within the inner passageway of the ferrule assembly when filled with epoxy. In an example, measuring capacitance of the ferrule assembly includes channeling a known current through electrodes and measuring a resulting voltage to derive capacitance.

[0009] In another aspect, the technology relates to a system for filling a fiber optic connector with epoxy, the system including: a connector support configured to hold the fiber optic connector such that opposing ends of a ferrule assembly that includes a ferrule and a ferrule hub are accessible, the ferrule assembly having an inner passageway extending therethrough; an epoxy source configured to inject epoxy into the inner passageway of the ferrule assembly; and a capacitance meter coupled to the ferrule assembly configured to measure capacitance within the ferrule assembly, and based on the measured capacitance within the ferrule assembly, the system stops injection of the epoxy into the inner passageway of the ferrule assembly via the epoxy source.

[0010] In an example, the capacitance meter includes a first electrode positioned proximate the ferrule and a second electrode positioned proximate the ferrule hub. In another example, the epoxy source includes a needle configured to inject epoxy into the inner passageway of the ferrule assembly, the second electrode coupled to the needle. In still another example, a probe is coupled to the first electrode and positioned relative to the ferrule. In yet another example, a distal end of the probe is configured to be inserted at least partially into the inner passageway of the ferrule assembly. In an example, a distance that the distal end of the probe is inserted into the inner passageway of the ferrule assembly is adjustable.

[0011] In another example, a cleaner is configured to physically contact the probe when removed from the inner passageway of the ferrule assembly so that epoxy is cleaned from the probe. In still another example, a probe inspector is configured to measure a straightness of the probe. In yet another example, the capacitance meter is configured to measure a capacitance value within the inner passageway of the ferrule assembly unfilled and a capacitance value within the inner passageway of the ferrule assembly filled with epoxy. In an example, the capacitance meter is configured to channel a known current through electrodes and measure a resulting voltage to derive capacitance.

[0012] A variety of additional inventive aspects will be set forth in the description that follows. The inventive aspects can relate to individual features and to combinations of features. It is to be understood that both the forgoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the broad inventive concepts upon which the examples disclosed herein are based. DESCRIPTION OF THE FIGURES

[0013] The following drawing figures, which form a part of this application, are illustrative of described technology and are not meant to limit the scope of the disclosure in any manner.

[0014] FIG. 1 is a top view of an exemplary LC style fiber optic connector.

[0015] FIG. 2 is a cross-sectional view of the fiber optic connector shown in FIG. 1 taken along line 2-2.

[0016] FIG. 3 is a partial perspective exploded view of the fiber optic connector shown in FIGS. 1 and 2.

[0017] FIG. 4 is a schematic view of a system for filling a fiber optic connector with epoxy.

[0018] FIG. 5 is a schematic view of a ferrule assembly coupled to the system shown in FIG. 4 prior to being injected with epoxy.

[0019] FIG. 6 is another schematic view of the ferrule assembly coupled to the system shown in FIG. 4 with injected epoxy therein.

[0020] FIG. 7 is a flowchart illustrating a method of filling a fiber optic connector with epoxy.

DETAILED DESCRIPTION

[0021] Various embodiments will be described in detail with reference to the drawings, wherein like reference numerals represent like parts and assemblies throughout the several views. Reference to various embodiments does not limit the scope of the claims attached hereto. Additionally, any examples set forth in this specification are not intended to be limiting and merely set forth some of the many possible embodiments for the appended claims.

[0022] During the assembly process of fiber optic connectors, epoxy is injected into a ferrule assembly prior the insertion of an optical fiber. When epoxy is overfilled relative to the ferrule, then the epoxy has to be wiped off a tip of the ferrule adding time and costs to the manufacturing and assembly process. Further, sometimes this wiping action does not completely remove the epoxy, and the remaining epoxy may interfere with operation of the connector, or reduce connector performance. When the epoxy is underfilled, there may be insufficient epoxy to hold the glass cladding layer of the optical fiber. This can result in incorrect placement or damage to the optical fiber, again affecting performance of the connector.

[0023] Furthermore, it is difficult to inject the same volume of epoxy into the ferrule assembly time after time during the manufacturing process. For proper epoxy fill, numerous variables influence the flow rate of the epoxy that is used to fill the connector. For example, the injection needle diameter can vary from syringe to syringe. The volume of the inner passageway can vary due to manufacturing tolerances. The viscosity of the epoxy over the life of the syringe can change and in some instances increase significantly. The syringe body itself can swell overtime and/or in response to the pressure that is applied. In addition, temperature and humidity in the ambient environment can affect the flow rate of the epoxy. Accordingly, using the same pressure and time to generate the charge of epoxy throughout the manufacturing process may result in overfill and/or underfill of the epoxy within the ferrule assembly and is problematic.

[0024] As described herein, the amount of epoxy that is injected into the ferrule assembly is monitored via capacitance within the ferrule assembly by a capacitance meter. Based on the capacitance properties of the epoxy, the injection of the epoxy into the ferrule assembly is stopped and the ferrule assembly being overfilled or underfilled with epoxy is reduced or eliminated. As such, the epoxy process of connector manufacturing has an increased efficiency and epoxy overflow on a face end of the connector is reduced or prevented.

[0025] In examples, the capacitance meter is utilized with one electrode being formed as a probe that is insertable into the ferrule and the other electrode being coupled to the needle that injects the epoxy into the ferrule hub. When epoxy extends between the two electrodes there is a detectable increase in capacitance within the ferrule assembly that is used to control and stop the epoxy from being injected into the ferrule assembly.

[0026] FIG. 1 is a top view of an exemplary LC style fiber optic connector 100. FIG. 2 is a cross-sectional view of the fiber optic connector 100 taken along line 2-2 in FIG. 1. FIG. 3 is a partial perspective exploded view of the fiber optic connector 100. Referring concurrently to FIGS. 1-3, the fiber optic connector 100 is generally configured to ensure fixed coupling to a matching format adapter (not shown). In the example, the fiber optic connector 100 includes a housing 102 having a front housing portion 104 and a rear housing portion 106. Additionally, the connector 100 includes a ferrule assembly 108 defined by a ferrule 110 and a hub 112 biased by a spring 114. A rear end 116 of the ferrule 110 is secured within the ferrule hub 112. When the fiber optic connector 100 is assembled, the ferrule hub 112 and the spring 114 are captured between the front housing portion 104 and the rear housing portion 106 of the connector housing 102, and a face end 118 of the ferrule 110 projects forward outwardly beyond a front end 120 of the housing 102. The spring 114 is configured to bias the ferrule 110 in a forward direction relative to the connector housing 102.

[0027] In some examples, the front housing portion 104 may be formed from a molded plastic. The front housing portion 104 defines a latch 122 extending from atop wall 124 of the front housing portion 104 towards a rear end 126. The latch 122 extends at an acute angle with respect to the top wall 124 of the front housing portion 104. The front housing portion 104 as depicted in the figures also includes a latch trigger 128 that extends from the rear end 126 of the front housing portion 104 towards the front end 120. The latch trigger 128 also extends at an acute angle with respect to the top wall 124. The latch trigger 128 is configured to come into contact with the latch 122 for flexibility moving the latch 122 downwardly. When the fiber optic connector 100 is placed in an LC format adapter (not shown) for optically coupling two optical fibers together, the latch 122 functions to lock the fiber optic connector 100 in place within the adapter. The fiber optic connector 100 may be removed from the adapter by depressing the latch trigger 128, causing the latch 122 to be pressed in a downward direction, freeing catch portions 130 of the latch 122 from the fiber optic adapter.

[0028] A strain relief boot 132 may be slid over a rear end 134 of the rear housing portion 106 and snap over a boot flange 136 to retain the boot 132 with respect to the connector housing 102. The rear end 134 of the rear housing portion 106 defines a crimp region 138 for crimping a fiber optic cable’s strength layer to the rear housing portion 106. For example, with the use of a crimp sleeve (not shown). An exterior surface 140 of the rear housing portion 106 defining the crimp region 138 can be textured (e.g., knurled, ridged, provided with small projections, etc.) to assist in in retaining the crimp on the housing 102.

[0029] In operation, the fiber optic connector 100 is configured to terminate an end of a fiber optic cable 142 and enable mechanical coupling and alignment of the end of an optical fiber 144. The optical fiber 144 generally includes a core with cladding that is surrounded by one or more strength layers 146 (e.g., a jacket). The end of the optical fiber 144 extends through the connector 100 and terminates at the face end 118 of the ferrule 110. The optical fiber 144 is secured within the ferrule 110 with cured epoxy. Movement of the ferrule 110 of the LC connector 100 in a rear direction relative to the connector housing 102 under the bias of the spring 114 causes the optical fiber 144 to be forced/displaced in a rear direction relative to the connector housing 102 and the jacket 146 of the fiber optic cable 142. The biased movement of the ferrule 110 allows for any geometry discrepancies and tolerance variations when axially mating two of the fiber optic connectors 100.

[0030] It should be appreciated that while an LC-style connector is illustrated and described above, the assembly methods and devices described herein can be used in any other connector style and/or type as required or desired. For example, SC, FC, or ST style connectors, and even multi-fiber style connectors (e.g., MPO).

[0031] FIG. 4 is a schematic view of a system 200 for filling the fiber optic connector 100 with epoxy 202. The system 200 includes a controller 204 and a capacitance meter 206 configured to measure capacitance within the ferrule assembly 108 while the epoxy 202 is dispensed from an epoxy source 208. Based on the capacitance within the ferrule assembly 108, the system 200 stops the epoxy source 208 from injecting epoxy 202 into the ferrule assembly 108. The process of injecting epoxy 202 into the ferrule assembly 108 is a blind process as the epoxy 202 is injected into an inner passageway within the ferrule assembly 108 that is at least partially within the connector housing 102. As such, instead of waiting for epoxy 202 to flow out of the ferrule assembly 108 to determine if the ferrule assembly 108 is filled with epoxy 202 and stopping the epoxy source 208, the capacitance meter 206 enables the system 200 to determine when the ferrule assembly 108 is filled with epoxy 202 to a required or desired level and stop the epoxy source 208 while reducing or preventing overfill and underfill of epoxy 202. [0032] The system 200 includes a connector support 210 configured to hold one or more connectors 100 such that opposing ends of a ferrule assembly 108 (e.g., the ferrule 110 and the ferrule hub 112 shown in FIG. 3) are accessible. In the example, the connector support 210 enables the connector housing 102 to releasably attach thereto and so that the ferrule 110 is positioned on one side of the support 210 and the rear end 126 of the housing 102 is positioned on the other side of the support 210. This configuration allows the connector 100 to be oriented so that both the face end 118 of the ferrule 110 and the ferrule hub 112 via the rear end 126 of the housing 102 are accessible within the system 200.

[0033] The epoxy source 208 is positioned proximate the rear end 126 of the housing 102 and includes a syringe 212 configured to hold the epoxy 202 and a needle 214 coaxially aligned with the ferrule assembly 108. In operation, the needle 214 is extended at least partially into the connector 100 and so that the epoxy 202 can be injected into the ferrule hub 112 from the rear. In an aspect, flow control of the epoxy 202 through the needle 214 is performed via air pressure and by communication with the controller 204.

[0034] The capacitance meter 206 is coupled to the ferrule assembly 108 and the epoxy source 208 at the needle 214. As such, the capacitance meter 206 is configured to measure the capacitance of a compound that is within the inner passageway of the ferrule assembly 108 prior to the optical fiber being secured within. The capacitance meter 206 may be any type of device that enables capacitance to be measured or determined of the material within the inner passageway of the ferrule assembly 108. For example, the capacitance meter 206 can detect and measure anything that is conductive or has a dielectric different than air. Air has less permittivity (e.g., about 1.0006a) when compared to epoxy 202 and as such epoxy 202 has more capacitance than air which is detectable by the capacitance meter 206. The capacitance meter 206 can determine capacitance by channeling a known current through electrodes and measuring a resulting voltage to derive capacitance. This is because capacitance is the ratio of the amount of electric charge stored on a conductor to a difference in electric potential. In an aspect, the capacitance meter 206 can be a multimeter, digital voltmeter, or the like and may include other metering functions other than capacitance. Capacitance may be measured in nano-farads (nF), and in some examples, an increase of about 0.04-0.05nF can indicate that epoxy 202 has filled the air void in the inner passageway between the electrodes, and thus, indicate for the system 200 that the epoxy 202 is at a required or desired level and without using a visual cue.

[0035] The capacitance meter 206 includes a first electrode 216 positioned proximate the ferrule 110 and a second electrode 218 positioned proximate the ferrule hub 112. In an aspect, the second electrode 218 is coupled to the needle 214 of the epoxy source 208. As such, the tip of the needle 214 that discharges epoxy 202 may be used as one electrode position for the capacitance meter 206. In the example, the needle 214 is formed from metal, and thus, is conductive of electrical charge. It should be appreciated that the needle 214 may be formed from other types of conductive materials that enable the capacitance meter 206 to function as described herein. The first electrode 216 is coupled to a probe 220 that is positioned at the face end 118 of the ferrule 110. In an aspect, the probe 220 is inserted at least partially into the inner passageway of the ferrule 110. As such, the tip of the probe 220 may be used as the other electrode position for the capacitance meter 206. This configuration enables the capacitance within the inner passageway of the ferrule assembly 108 to be measured by the capacitance meter 206.

[0036] The controller 204 is coupled in communication to both the capacitance meter 206 and the epoxy source 208 and is configured to control operation of the system 200 as described herein. For example, the controller is configured to monitor the capacitance within the inner passageway of the ferrule assembly 108, control operation of the epoxy source 208 and the injection of the epoxy 202 into the ferrule assembly 108, the position of the probe 220 relative to the ferrule 110, and the like. In another example, the controller 204 may use the capacitance meter 206 to compare a capacitance value within the inner passageway of the ferrule assembly 108 unfilled (e.g., with air) with a capacitance value within the inner passageway of the ferrule assembly 108 filled with epoxy 202 so as to determine when to stop the epoxy source 208 from injecting epoxy 202.

[0037] In the example, the controller 204 includes at least one central processing unit and a system memory. The system memory includes a random access memory (“RAM”) and a read-only memory (“ROM”). The controller further includes a mass storage device. The mass storage device is able to store software instruction and data.

[0038] The mass storage device is connected to a CPU. The mass storage device provides non-volatile, non-transitory storage for the controller 204. Although the description of computer-readable date storage media contained herein refers to a mass storage device, such as a hard disk or solid state disk, it should be appreciated by those skilled in the art that computer-readable data storage media can be any available non-transitory, physical device or article of manufacture from which the central display station can read data and/or instructions.

[0039] Computer-readable data storge media includes volatile and non-volatile removable and non-removeable media implemented in any method or technology for storage of information such as computer-readable software instructions, data structures, program modules, or other data. Example types of computer-readable data storage media include, but are not limited to, RAM, ROM, EPROM, EEPROM, flash memory or other solid state memory technology, CD-ROMs, digital versatile discs (“DVDs”), other optical storage media, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by the testing/assessment computing device.

[0040] The mass storage device and the RAM of the controller 204 can store software instructions and data. The software instructions include an operating system suitable for controlling the controller 204. The mass storage device and/or RAM also store software instructions and software application that, when executed by the CPU, cause the control to provide the functionality of the controller 204 as described herein.

[0041] According to various embodiments, the controller 204 may operate in a networked environment using logical connections to remote network devices through a network, such as a wireless network, the Internet, or another type of network. The controller 204 also includes an input/output controller for receiving and processing input from a number of other devices, including a touch user interface display screen, or another type of input device.

[0042] Additionally or alternatively, the controller 204 may be an electro-mechanical controller 204 with a series of electrical circuits, switches, and the like so as to control the operation of the syringe 212 and the flow of epoxy 202 into the ferrule assembly 108 as described herein.

[0043] Once the ferrule assembly 108 is filled with epoxy 202, the epoxy source 208 and the probe 220 are removed from the connector 100 so that the optical fiber may be inserted therein. Once the optical fiber is inserted, the optical fiber is aligned within the ferrule 110 and the epoxy 202 cured. In an aspect, curing the epoxy 202 may include heating the epoxy. In other aspects, curing the epoxy 202 may include applying one or more reactants. After curing, the excess optical fiber extending from the ferrule 110 may be cleaved and the face end of the ferrule 110 polished.

[0044] When the probe 220 is removed from the ferrule 110, the probe 220 may have epoxy residue on the portion of the probe 220 that is inserted into the ferrule 110. However, epoxy build-up on the probe 220 may increase down time for the system 200 because of excess cleaning and maintenance, and epoxy build-up often requires a large number of replacement/spare components for operation of the system 200. As such, the system 200 also includes a cleaner 222 for the probe 220 so that the probe 220 may be cleaned and epoxy residue removed prior to subsequent use. The cleaner 222, thereby, increases manufacturing efficiencies and performance of the probe 220. In an aspect, the cleaner 222 is configured to physically contact the probe 220 when the probe 220 is removed from the inner passageway of the ferrule 110. The cleaner 222 can be a tape reel like ADE, FSC, or the like. In other aspects, the cleaner 222, may be a rubber gland, or the like. In examples, the cleaner 222 may be at a fixed location within the system 200 so that as the probe 220 is withdrawn from the ferrule 110, the probe 220 contacts the cleaner 222. In other examples, the cleaner 222 may be coupled to the controller 204 so that the position of the cleaner 222 is controllable and can be moved to contact the probe 220 as required or desired.

[0045] Additionally or alternatively, the inner passageway of the ferrule 110 is small, and for example, around 125 microns (pm). As such, the probe 220 in order to fit within the inner passageway of the ferrule 110 is required to be smaller than the inner passageway. This results in the probe 220 being smaller than 125 pm and prone to being bent during use. In an aspect, the probe may be an 8 Ip tungsten metal probe. The system 200 may also include a probe inspector 224 that is configured to monitor the straightness/curvature of the probe 220, and when the probe 220 bends too much to be operable within the inner passageway of the ferrule 110, the system 200 may be triggered to replace the probe 220. In the example, the probe inspector 224 may be any type of device that measures the straightness/curvature of the probe 220, for example, but not limited to, an optical probe and the like that is coupled to the controller 204 for control thereof. [0046] FIG. 5 is a schematic view of the ferrule assembly 108 coupled to the system 200 (fully shown in FIG. 4) prior to being injected with epoxy. The ferrule assembly 108 includes the ferrule 110 and the ferrule hub 112. An inner passageway 148 is defined within the ferrule assembly 108 and it extends along a centerline of both the ferrule 110 and the ferrule hub 112. The inner passageway 148 is also open at each end of the ferrule assembly 108, the face end 118 of the ferrule 110 and a rear end 150 of the ferrule hub 112. In the example, the inner passageway 148 has a larger diameter in the ferrule hub 112 than in the ferrule 110. The inner passageway 148 is configured to receive the optical fiber (not shown) such that it is positioned at the face end 118 of the ferrule 110. The optical fiber is secured to the ferrule 110 via epoxy as described herein.

[0047] The system 200 that is used to fill the ferrule assembly 108 with epoxy is configured to removably couple to the ferrule assembly 108 so that epoxy can be injected into the inner passageway 148. Once the inner passageway 148 is filled with epoxy, the system 200 can be removed so that the optical fiber may be inserted therein and secured. The system 200 includes the capacitance meter 206 with the first electrode 216 formed by the probe 220 and the second electrode 218 formed by the needle 214 that is utilized to inject epoxy. The needle 214 is positioned at the rear end 150 of the ferrule hub 112 and aligned with the inner passageway 148. The probe 220 is inserted into the inner passageway 148 at the other end and through the face end 118 of the ferrule 110.

[0048] In the example, the distal end of the probe 220 is inserted into the ferrule 110 at a distance D from the face end 118. The distance D that the probe 220 is inserted into the ferrule 110 can be adjustable by the system 200. For example, based on the flow characteristics (e.g., flow rate) of the epoxy and/or the response time of the system 200 to measure the capacitance, determine that the flow of epoxy should be stopped, and stop the epoxy flow, the distance that the probe 220 is inserted can change so that the inner passageway 148 is not overfilled or underfilled during the manufacturing process. Additionally or alternatively, the volume of the fiber optic may be accounted for so as to reduce or prevent epoxy from overflowing at the face end 118 of the ferrule 110 when being inserted into the inner passageway 148 that is filled with epoxy.

[0049] FIG. 6 is another schematic view of the ferrule assembly 108 coupled to the system 200 (fully shown in FIG. 4) with injected epoxy 202 therein. Certain components are described above, and thus, are not necessary described further. In operation, once the system 200 is in position relative to the ferrule assembly 108, the needle 214 is used to fill the inner passageway 148 of both the ferrule hub 112 and ferrule 110 with epoxy 202. The needle 214 is positioned at the rear end 150 of the ferrule hub 112 so that the epoxy 202 is injected into the ferrule hub 112 prior to reaching the ferrule 110. As the epoxy 202 fills the inner passageway 148, the epoxy 202 axially travels within the inner passageway 148 towards the face end 118 of the ferrule 110. Because the distal end of the probe 220 is positioned within the ferrule 110, once the epoxy 202 reaches the distal end, the capacitance meter 206 is able to detect a change of capacitance within the inner passageway 148 because the capacitance of the epoxy 202 is different than air (e.g., the unfilled configuration). This detection of the epoxy 202 reaching the distal end of the probe 220 may trigger the system 200 to stop the injection of epoxy 202. In an aspect, a 3 cc syringe 212 (shown in FIG. 4) has approximately 1 gram of epoxy 202 that may be utilized to fill approximately 200 SC connectors during the manufacturing/assembly process.

[0050] In the example, the flow of epoxy 202 into the inner passageway 148 may be generated via air pressure, and as such, the system 200 can trigger a stoppage of air pressure so as to stop the injection of epoxy 202. It should be appreciated that one of ordinary skill in the art would understand that there are other methods and systems that may be used to inject and stop the injection of epoxy 202 into the ferrule assembly 108 while using the capacitance monitoring as described herein.

[0051] During the filling of the inner passageway 148 with epoxy 202, both overfilling and underfilling are undesirable. If the ferrule 110 is overfilled with epoxy 202, the epoxy 202 may be pushed out of the face end 118 and this excess epoxy 202 may frustrate subsequent assembly procedures such as alignment of the optical fiber, curing the epoxy, cleaving the excess optical fiber, and/or polishing the face end 118. If the ferrule 110 is underfilled with epoxy 202, the optical fiber may not be properly secured therein. Furthermore, and as described above, once the epoxy 202 is detected by the distal end of the probe 220, the injection shut-off of the epoxy flow may not be instantaneous. Accordingly, to account for operational lag time in the system 200, the distal end of the probe 220 is inserted the distance D from the face end 118 of the ferrule 110. This distance D may be based at least partially on the volume of epoxy 202 injected into the inner passageway 148 after the stop signal is sent within the system 200 and before the flow of epoxy 202 actually is stopped.

[0052] Additionally, the optical fiber that is inserted into the inner passageway 148 also has a volume that can be accounted for by the position of the probe 220. For example, if the epoxy 202 is positioned right at the face end 118 of the ferrule 110 prior to the optical fiber being inserted, the displacement volume of the optical fiber with respect to the epoxy 202 will push epoxy 202 out of the ferrule 110 upon insertion. Accordingly, to account for the optical fiber volume, the distance D of the probe 220 can be adjusted accordingly. As such, the position of the probe 220 within the ferrule 110 is adjustable so that the epoxy 202 is filled to the face end 118 with as little overflow as possible once the optical fiber is extended through the ferrule assembly 108.

[0053] In some aspects, the system 200 may be configured to monitor the temperature and/or humidity of the epoxy 202 within the epoxy source 208 (shown in FIG. 4) and further adjust the position of the probe 220 so as to account for the change in viscosity of the epoxy 202 as the temperature and/or humidity changes.

[0054] In the example, the system 200 may monitor one or more operational conditions of the epoxy fill procedure (e.g., flow rate of epoxy, needle and/or syringe shape and size, ferrule assembly shape and size, epoxy viscosity, etc.) so as to generate a feedback algorithm for real time positioning of the distal end of the probe 220 and creating a fill level volume 226 of epoxy 202 that reduces or prevents both underfilling and overfilling of the epoxy. As described herein, filling the inner passageway 148 with epoxy 202 may not include completely filling the inner passageway 148 all the way to the face end 118 of the ferrule 110. Rather, filling the inner passageway 148 with epoxy 202 includes volumes 226 of epoxy that may not reach all the way to the face end 118 of the ferrule 110 due to the above described considerations for overfill and underfill of epoxy.

[0055] FIG. 7 is a flowchart illustrating a method 300 of filling a fiber optic connector with epoxy. The example methods and operations can be implemented or performed by the systems and devices described herein (e.g., connector 100, system 200, etc.). It is appreciated that the fiber optic connector assembled via the method 300 can be any type of connector as required or desired. [0056] The method 300 begins with providing a ferrule assembly that includes a ferrule and a ferrule hub, the ferrule assembly having an inner passageway configured to receive epoxy (operation 302). This inner passageway is small and it is difficult to properly fill with epoxy because it is internal within the ferrule and epoxy can fluctuate in viscosity during the manufacturing process. As such, a capacitance meter is positioned relative to the ferrule assembly (operation 304). The capacitance meter is configured to measure capacitance within the inner passageway and detect when the inner passageway is filled with epoxy. The method 300 next includes injecting epoxy into the inner passageway of the ferrule assembly (operation 306). For example, epoxy can be injected via a needle and syringe source, but other type of injection systems are also contemplated herein. In an aspect, the time to fill the inner passageway of the ferrule assembly is between about 0.5 - 2 seconds.

[0057] While the epoxy is injected into the ferrule assembly, the capacitance within the ferrule assembly is measured via the capacitance meter (operation 308). Then based on the measured capacitance within the ferrule assembly, the epoxy being injected into the inner passageway of the ferrule assembly is stopped (operation 310). By using the capacitance meter to detect the position of the epoxy within the ferrule assembly, the epoxy can be more accurately filled to a required or desired level within the ferrule assembly without overfilling or underfilling. In an aspect, measuring capacitance of the ferrule assembly may include comparing a capacitance value within the inner passageway of the ferrule assembly when empty with a capacitance value within the inner passageway when filled with epoxy. Additionally, the capacitance meter may measure capacitance within the ferrule assembly by channeling a known current through electrodes and measuring a resulting voltage to derive capacitance. This is because it is known that capacitance is the ratio of the amount of electric change stored on a conductor to a difference in electric potential.

[0058] In some examples, positioning the capacitance meter may include positioning a first electrode relative to the ferrule (operation 312) and positioning a second electrode relative to the ferrule hub (operation 314). The first electrode may be coupled to a probe positioned at the ferrule. In an aspect, a distal end of the probe is at least partially inserted into the ferrule from the face end and into the inner passageway. The distance that the probe is inserted into the inner passageway of the ferrule is adjustable. This insertion distance can be based at least partially by the lag time of the system from when the epoxy is detected by the probe and when the flow of epoxy is actually stopped. In another aspect, the insertion distance can be based at least partially by the optical fiber volume when the optical fiber is inserted therein. In still another aspect, the insertion distance can be based at least partially by the viscosity of the epoxy. The second electrode may be coupled to a needle that is configured to inject epoxy into the inner passageway of the ferrule assembly.

[0059] The method 300 may also include cleaning epoxy from the capacitance meter after the ferrule assembly is filled (operation 316). This reduces epoxy build up on the system and increases the manufacturing efficiencies of the connector. In an aspect, the probe is removed from the inner passageway of the ferrule and epoxy is cleaned from the probe. The cleaning step may be performed by physically contacting the probe with a cleaning device so as to remove or wipe epoxy from the outer surface of the probe.

[0060] Because the inner passageway of the ferrule is small, the probe also is required to be small so that it can fit therein. As such, the probe may be vulnerable to bending and if so it will need to be replaced. Accordingly, the method 300 may include that after the probe is removed from the inner passageway of the ferrule, the probe may be examined for straightness/curvature, and if the probe is no longer straight, replace the probe based at least partially on its curvature (operation 318). For example, a probe inspector may be configured to examine the straightness/curvature of the probe and when the probe bends too much to be operable within the inner passageway of the ferrule the system can be triggered to replace the probe.

[0061] As described herein, it has been found that when two electrodes are connected through epoxy used in connector assemblies, the epoxy induces a measurable increase in capacitance. For example, the capacitance is in the scale of nano-farads and which is capable of being measured by a capacitance meter. Thus, a small elongated probe can be used to connect to one of the electrodes and be inserted into the inner passageway of the ferrule. The opposite electrode may be attached to the needle that is positioned at the ferrule hub and utilized for injecting epoxy into the inner passageway. When epoxy is dispensed from the needle, there is a detectable jump in capacitance once the epoxy extends between the two electrodes. This detection of the capacitance jump identifies a filled configuration of the ferrule assembly during the manufacturing process. As such, the epoxy dispensing process may be completed more efficiently with epoxy on the face end of the ferrule reduced or prevented.

[0062] The various embodiments described above are provided by way of illustration only and should not be construed to limit the claims attached hereto. Those skilled in the art will readily recognize various modifications and changes that may be made without following the example embodiments and application illustrated and described herein, and without departing from the true spirit and scope of the following claims.

Claims

CLAIMS What is claimed is:

1. A method of fdling a fiber optic connector with epoxy, the method comprising: providing a ferrule assembly including a ferrule and a ferrule hub, the ferrule assembly having an inner passageway configured to receive epoxy; positioning a capacitance meter relative to the ferrule assembly; injecting epoxy into the inner passageway of the ferrule assembly; measuring capacitance within the ferrule assembly via the capacitance meter while epoxy is injected into the inner passageway of the ferrule assembly; and based on the measured capacitance within the ferrule assembly, stopping epoxy being injected into the inner passageway of the ferrule assembly.

2. The method of claim 1, wherein positioning the capacitance meter relative to the ferrule assembly includes: positioning a first electrode relative to the ferrule; and positioning a second electrode relative to the ferrule hub.

3. The method of claim 2, wherein positioning the second electrode relative to the ferrule hub includes coupling the second electrode to a needle that injects epoxy into the inner passageway of the ferrule assembly.

4. The method of any one of claims 2 and 3, wherein positioning the first electrode relative to the ferrule includes coupling the first electrode to a probe positioned relative to the ferrule.

5. The method of claim 4, wherein positioning the first electrode relative to the ferrule includes inserting at least a portion of the probe into the inner passageway of the ferrule assembly.

6. The method of claim 5, further comprising adjusting a distance that a distal end of the probe is inserted into the inner passageway of the ferrule assembly.

7. The method of any one of claims 5 and 6, further comprising removing the probe from the inner passageway of the ferrule assembly and cleaning epoxy from the probe.

8. The method of any one of claims 5-7, further comprising removing the probe from the inner passageway of the ferrule assembly and replacing the probe based at least partially on its curvature.

9. The method of any one of the preceding claims, wherein measuring capacitance within the ferrule assembly includes comparing a capacitance value within the inner passageway of the ferrule assembly when empty with a capacitance value within the inner passageway of the ferrule assembly when filled with epoxy.

10. The method of any one of the preceding claims, wherein measuring capacitance of the ferrule assembly includes channeling a known current through electrodes and measuring a resulting voltage to derive capacitance.

11. A system for filling a fiber optic connector with epoxy, the system comprising: a connector support configured to hold the fiber optic connector such that opposing ends of a ferrule assembly that includes a ferrule and a ferrule hub are accessible, the ferrule assembly having an inner passageway extending therethrough; an epoxy source configured to inject epoxy into the inner passageway of the ferrule assembly; and a capacitance meter coupled to the ferrule assembly configured to measure capacitance within the ferrule assembly, wherein based on the measured capacitance within the ferrule assembly, the system stops injection of the epoxy into the inner passageway of the ferrule assembly via the epoxy source.

12. The system of claim 11, wherein the capacitance meter includes a first electrode positioned proximate the ferrule and a second electrode positioned proximate the ferrule hub.

13. The system of claim 12, wherein the epoxy source includes a needle configured to inject epoxy into the inner passageway of the ferrule assembly, the second electrode coupled to the needle.

14. The system of any one of claims 12 and 13, further comprising a probe coupled to the first electrode and positioned relative to the ferrule.

15. The system of claim 14, wherein a distal end of the probe is configured to be inserted at least partially into the inner passageway of the ferrule assembly.

16. The system of claim 15, wherein a distance that the distal end of the probe is inserted into the inner passageway of the ferrule assembly is adjustable.

17. The system of any one of claims 15 and 16, further comprising a cleaner configured to physically contact the probe when removed from the inner passageway of the ferrule assembly so that epoxy is cleaned from the probe.

18. The system of any one of claims 15-17, further comprising a probe inspector configured to measure a straightness of the probe.

19. The system of any one of claims 11-18, wherein the capacitance meter is configured to measure a capacitance value within the inner passageway of the ferrule assembly unfilled and a capacitance value within the inner passageway of the ferrule assembly filled with epoxy.

20. The system of any one of claims 11-19, wherein the capacitance meter is configured to channel a known current through electrodes and measure a resulting voltage to derive capacitance.