JP2014134578A - Optical fiber attachment ferrule manufacturing method, optical fiber attachment ferrule and optical connector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently manufacture an optical fiber attachment ferrule having satisfactory, stable quality by preventing occurrence of damage such as crack or chip in the optical fiber when the front end of the ferrule, through which the optical fiber is passed and held, is polished.SOLUTION: A first through-hole 4 through which an optical fiber cable 20 is passed through, and a second through-hole 5 through which an optical fiber is passed through are continuously provided along the central axis of the ferrule. An adhesive reservoir 6 continuing from the front end of the second through-hole 5 and having a diameter larger than the second through-hole 5 are provided in the form of a recess at the front end of the second through-hole 5. After adhesive 11 is injected into the adhesive reservoir 6, second through-hole 5, and first through-hole 4, the optical fiber cable 20 is passed through the first through-hole, and the optical fiber 21 is passed through the second through-hole 5 and adhesive reservoir 6, and the adhesive is cured. Then, the front end face of the optical fiber 21 is exposed by polishing the front end of the ferrule 1.

Description

  The present invention relates to a manufacturing method of an optical fiber mounting ferrule, an optical fiber mounting ferrule manufactured by the method, and an optical connector including the optical fiber mounting ferrule, and more specifically, when polishing a front end of a ferrule penetrating and holding an optical fiber. The optical fiber is prevented from being damaged such as cracks and chips.

  In recent years, communication using optical fiber cables has become widespread in automobiles, and optical coupling between optical fiber cables is performed via an optical connector attached to a cable terminal. The optical connector includes a ferrule (optical fiber mounting ferrule) in which an optical fiber that is an optical fiber cable and its core wire is held through and a front end surface of the optical fiber is exposed at a front end. By fitting the optical connector provided with the optical fiber mounting ferrule to the optical connector of the connection counterpart, the front end surfaces of the optical fibers at the front ends of the ferrules can be brought into contact with each other for optical coupling.

The optical fiber mounting ferrule has a structure as shown in FIG. 6, for example.
The cylindrical ferrule 100 is provided with a through hole 101 that penetrates the optical fiber cable 110 along the central axis, and a through hole 102 that penetrates the optical fiber 111 protruding from the front end of the coating of the optical fiber cable 110. Yes. After passing the optical fiber cable 110 and the optical fiber 111 through the through holes 101 and 102 of the ferrule 100 as shown in FIG. 6A, the gaps of the through holes 101 and 102 as shown in FIGS. 6B and 6C. The resin material 103 and the adhesive 104 are injected into this. Thereafter, the front end of the ferrule 100 that penetrates and holds the optical fiber 111 is polished to obtain the optical fiber mounting ferrule 105 in which the front end surface of the optical fiber 111 is exposed at the front end of the ferrule 100 as shown in FIG. [See JP 2007-279576 A (Patent Document 1)].

  Note that the optical fiber 111 held through the through hole 102 at the time of polishing wobbles and bends to cause damage such as cracking or chipping inside the optical fiber 111, and as a result, good optical coupling cannot be performed. Since there is a case, a raised portion 106 made of an adhesive, for example, as shown in FIG. 6C is formed at the front end of the ferrule 100 from which the optical fiber 111 is projected, and the raised portion around the protruding portion of the optical fiber 111 is formed. The optical fiber 111 is prevented from being damaged by polishing while being surrounded and stably held by the portion 106.

JP 2007-279576 A

  However, in the method of forming the raised portion 106 made of the adhesive around the optical fiber 111 protruding from the front end of the ferrule 100 as described above and then polishing the portion, the number of steps for forming the raised portion 106 increases. As a result, the manufacturing efficiency is reduced, and the size and shape of the raised portion 106 cannot be accurately controlled because the diameter of the optical fiber 111 is small, so that the quality of the polished optical fiber mounting ferrule is not stable.

  The present invention has been made in view of the above problems, and prevents the occurrence of damage such as cracks and chips in the optical fiber when polishing the front end of the ferrule penetrating and holding the optical fiber. It is an object to efficiently manufacture an optical fiber mounting ferrule having quality.

In order to solve the above-mentioned problem, as a first invention, the center of the ferrule includes a first through-hole through which the optical fiber cable passes and a second through-hole through which the optical fiber protruded from the front end of the coating of the optical fiber cable. An adhesive reservoir that is provided continuously along the axis and continuous with the front end of the second through hole and having a diameter larger than that of the second through hole is recessed at the front end of the ferrule.
After injecting the adhesive into the adhesive reservoir, the second through hole and the first through hole of the ferrule,
An optical fiber cable is passed through the first through hole and an optical fiber protruding from the front end of the coating of the optical fiber cable is passed through the second through hole and the adhesive reservoir to cure the adhesive. ,
Next, a method for manufacturing an optical fiber mounting ferrule is provided, wherein the front end of the ferrule having an optical fiber penetrated and fixed to the adhesive reservoir is polished to expose the front end surface of the optical fiber.

  As described above, in the first invention, the adhesive reservoir having a diameter larger than that of the second through hole is recessed in the front end of the ferrule continuously from the front end of the second through hole of the ferrule that allows the optical fiber to pass therethrough. And injecting the adhesive into the adhesive reservoir, the second through hole, and the first through hole penetrating the optical fiber cable, and then inserting the optical fiber cable into the first through hole and the second optical fiber at the tip. It is set as the structure penetrated to a through-hole and an adhesive reservoir part. By injecting the adhesive into the adhesive reservoir, the second through hole, and the first through hole and then penetrating the optical fiber cable and the optical fiber, the optical fiber is inserted into the adhesive reservoir and the second through hole. The optical fiber cable can be securely fixed to the first through hole to stably hold the optical fiber. In particular, in the vicinity of the front end of the ferrule to be polished, the optical fiber is held in a more stable state by the adhesive in the adhesive reservoir portion having a diameter larger than that of the second through hole. It is possible to effectively prevent the occurrence of damage such as cracking or chipping in the optical fiber that is hardly generated. Also, since the adhesive is injected and filled in the adhesive reservoir when the adhesive is injected into the first and second through holes, the raised portion made of the adhesive is inserted into the ferrule after passing through the optical fiber as in the prior art. Since it is not necessary to form the front end, the manufacturing efficiency is improved, and the size and shape of the adhesive reservoir are predetermined, so that the quality of the optical fiber mounting ferrule after polishing can be stabilized in a good state. .

  In the adhesive injection step, a nozzle for discharging the adhesive from the tip is inserted to the vicinity of the front end of the first through hole to inject the adhesive into the second through hole and the adhesive reservoir, and then It is preferable to inject an adhesive into the first through hole while pulling the nozzle backward.

  As described above, by inserting the nozzle that discharges the adhesive to the vicinity of the front end of the first through hole, reliable injection of the adhesive into the second through hole penetrating the optical fiber and the adhesive reservoir is performed. It becomes possible. Further, by discharging the adhesive while pulling out the nozzle backward, the adhesive can be uniformly injected into the first through hole penetrating the optical fiber cable while preventing air bubbles from entering.

  As the adhesive, an adhesive having a viscosity of 3000 to 6000 cPs at 23 ° C. is preferably used.

Specifically, the viscosity is a viscosity at 23 ° C. and 50 rpm based on ASTM test method D2393, and the viscosity is more preferably 3000 to 5000 cPs.
By setting the viscosity to 3000 to 6000 cPs, it is possible to prevent the injected adhesive from leaking out from the front end of the adhesive reservoir or the rear end of the first through hole, and the adhesive that the optical fiber takes out when penetrating the optical fiber. The amount can also be limited. Further, by setting the viscosity to 3000 to 6000 cPs, the usable time (POT Life) of the adhesive can be reduced to 3 hours or less, so that the optical fiber mounting ferrule can be efficiently manufactured.
For example, an epoxy adhesive is preferably used as the adhesive.

  Moreover, it is preferable that the ferrule is formed of zirconia or liquid crystal polymer (LCP), and an adhesive having a hardness after curing smaller than the hardness of the ferrule and the optical fiber is used as the adhesive.

Since both zirconia and liquid crystal polymer (LCP) have high hardness and high dimensional accuracy, a highly reliable ferrule capable of accurate PC connection (physical contact) between optical fibers can be obtained.
Further, by making the hardness of the adhesive after curing smaller than the hardness of a ferrule or an optical fiber, low-hardness adhesion can be achieved between the optical fiber penetrating the second through hole and the peripheral wall of the second through hole. Since the agent layer is formed, it is possible to prevent the optical fiber from being damaged such as cracking or chipping due to an impact coming into contact with the peripheral wall of the second through hole having high hardness. Moreover, by making the hardness of the adhesive smaller than that of the optical fiber, the front end face of the optical fiber can be easily exposed from the front end face of the adhesive filled in the adhesive reservoir during polishing. The hardness of the adhesive after curing is preferably about 80 to 90 in Shore D hardness, for example.

The adhesive reservoir has a substantially cylindrical shape or a substantially frustoconical shape that expands toward the front end, and passes through the optical fiber along the central axis of the adhesive reservoir, and is formed on the front end surface of the adhesive reservoir. It is preferable that the diameter is 3 times or more of the diameter of the optical fiber, and the depth of the adhesive reservoir is 3 times or more, more preferably 5 times or more of the diameter of the optical fiber.
By setting the adhesive reservoir portion to the dimensions, the front end side portion of the optical fiber can be held in a more stable state.

Moreover, in 2nd invention, the optical fiber mounting ferrule manufactured by the manufacturing method of 1st invention is provided.
In the optical fiber mounting ferrule of the second invention, since the optical fiber is not damaged such as cracking or chipping, good optical coupling is possible.

  Furthermore, the third invention also provides an optical connector in which the optical fiber mounting ferrule of the second invention is inserted and held in the connector housing.

  As described above, in the first invention, the adhesive reservoir portion having a diameter larger than that of the second through hole is recessed in the front end of the ferrule continuously from the front end of the second through hole of the ferrule that allows the optical fiber to pass therethrough. The adhesive is poured into the first through hole penetrating the adhesive reservoir, the second through hole, and the optical fiber cable, and then the optical fiber cable and the optical fiber are passed through. Therefore, the optical fiber is securely fixed to the adhesive reservoir and the second through hole, and the optical fiber cable is securely fixed to the first through hole to stably hold the optical fiber, and in the vicinity of the front end of the ferrule for polishing, Since the optical fiber is held in a more stable state with the adhesive in the adhesive reservoir having a diameter larger than that of the second through hole, it is possible to effectively prevent the optical fiber from being damaged such as cracks and chips during polishing. . In addition, when the adhesive is injected into the first and second through holes, the adhesive is also filled and filled in the adhesive reservoir, so that the manufacturing efficiency is not lowered, and the size and shape of the adhesive reservoir are also set in advance. Therefore, the quality of the optical fiber mounting ferrule after polishing can be stabilized.

  Therefore, the optical fiber mounting ferrule of the second invention and the optical connector of the third invention equipped with the optical fiber mounting ferrule are also free from damage such as cracks or chips in the optical fiber that passes through. Better optical coupling becomes possible.

The ferrule before optical fiber mounting of embodiment of this invention is shown, (A) is a perspective view, (B) is AA sectional view taken on the line. (A) is a state in which the discharge nozzle of the dispenser is inserted to the vicinity of the front end of the first through hole and the adhesive is being injected into the second through hole and the adhesive reservoir, and (B) is while pulling out the discharge nozzle to the rear. It is a partial cross section figure which shows the state which has inject | poured the adhesive agent to the 1st through-hole. (A) is a partial cross-sectional view showing a state in which an optical fiber cable is fixed to the first through hole of the ferrule and an optical fiber is fixed to the second through hole and the adhesive reservoir, and (B) is a front end of the ferrule. FIG. 5 is an enlarged cross-sectional view of a main part of an optical fiber mounting ferrule completed by polishing the fiber. It is a partial cross section figure of the optical connector provided with the optical fiber mounting ferrule. It is sectional drawing of another ferrule which changed the shape of the adhesive reservoir part. It is a figure which shows a prior art example, (A) is a partial cross section figure which shows the state which penetrated the optical fiber cable and the optical fiber in the through-hole of the ferrule, (B) is the state which filled the resin material into the space | gap of the through-hole. (C) is a partial cross-sectional view showing a state in which an adhesive is injected into the gap of the through hole. (D) is a partial cross-sectional view of an optical fiber mounting ferrule formed by polishing the front end of the ferrule. It is.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 4 show an embodiment of the present invention.
In this embodiment, first, a ferrule 1 as shown in FIG. 1 is manufactured. The ferrule 1 includes a substantially cylindrical ferrule main body 2 that penetrates the optical fiber cable 20 and the optical fiber 21 that protrudes from the front end of the coating of the optical fiber cable 20, and a radial direction from an intermediate position of the ferrule main body 2. It consists of a protruding annular flange 3. The ferrule body 2 is provided with a large-diameter first through hole 4 through which the optical fiber cable 20 penetrates and a small-diameter second through hole 5 through which the optical fiber 21 penetrates along the central axis of the ferrule 1. The first through hole 4 and the second through hole 5 are made continuous through a reduced diameter portion 5 a at the rear end of the through hole 5. In the present embodiment, the diameter of the second through hole 5 is set to be 0.8% larger than the diameter of the optical fiber 21 that passes therethrough.

  Further, an adhesive reservoir portion 6 having a diameter larger than that of the second through hole 5 is recessed in the front end of the ferrule main body portion 2 continuously from the front end of the second through hole 5. As will be described later, the adhesive 11 is injected and filled in the adhesive reservoir 6 and the front end side portion of the optical fiber 21 that has passed through the second through hole 5 penetrates the adhesive reservoir 6. Let The adhesive reservoir 6 has a frustoconical shape that expands toward the front end, and is at least three times the diameter of the optical fiber 21 that penetrates the diameter D of the front end surface of the adhesive reservoir 6 (four times in this embodiment). Further, the depth H of the adhesive reservoir 6 is also set to 3 times or more (3 times in this embodiment) of the diameter of the optical fiber 21. The central axis of the adhesive reservoir 6 is made to coincide with the central axes of the first and second through holes 4 and 5. In addition, in this embodiment, although it is set as the truncated cone shape expanded toward a front end, it is good also as a column shape as shown in FIG.

  The ferrule 1 having the above configuration is manufactured from zirconia. Specifically, a raw material in which zirconia powder and a thermoplastic resin binder are mixed is put into an injection molding machine and molded. After the obtained molded body is sintered in a high-temperature firing furnace, predetermined post-processing is performed. Thus, the ferrule 1 is manufactured. In this embodiment, the ferrule 1 is formed by injection molding, but it can also be formed by extrusion. In this embodiment, zirconia is used as a raw material for ferrule 1, but a liquid crystal polymer (LCP) may be used.

  Next, as shown in FIG. 2A, the dispenser 10 for discharging the adhesive is inserted from the rear end opening of the first through hole 4 of the manufactured ferrule 1, and the discharge nozzle 10 a at the tip of the first through hole 4 The dispenser 10 is moved forward until it reaches the vicinity of the front end. The adhesive 11 is injected into the second through hole 5 and the adhesive reservoir 6 by discharging the adhesive 11 from the discharge nozzle 10a at the position, and then the dispenser 10 is moved backward as shown in FIG. The adhesive 11 is also injected into the first through hole 4 by discharging the adhesive 11 from the discharge nozzle 10a while being pulled out.

  In the present embodiment, an epoxy adhesive (trade name: EPO-TEK 353ND, manufactured by Epoxy Technology Co., Ltd.) is used as the adhesive 11. The adhesive 11 has a viscosity of 3000 to 5000 cPs at 23 ° C. and 50 rpm based on ASTM test method D2393. The hardness after curing is smaller than the hardness of the ferrule 1 and the optical fiber 21 and is 85 in Shore D hardness.

Subsequently, as shown in FIG. 3A, the optical fiber cable 20 passes through the first through hole 4 into which the adhesive 11 has been injected, and the second through hole 5 and the adhesive reservoir portion into which the adhesive 11 has been injected. 6 through the optical fiber 21 along the central axis, and the adhesive 11 is cured.
After the adhesive is cured, as shown in FIG. 3B, the front end 21a of the optical fiber 21 is exposed and mirror-finished by polishing the front end of the ferrule 1 that penetrates and fixes the optical fiber 21 to the adhesive reservoir 6 The optical fiber mounting ferrule 30 is completed.

  As described above, in the present embodiment, the adhesive reservoir 6 having a diameter larger than that of the second through hole 5 is formed continuously with the front end of the second through hole 5 of the ferrule 1 through which the optical fiber 21 passes. The optical fiber cable 20 and the optical fiber 21 are penetrated after the adhesive 11 is injected into the adhesive reservoir 6, the second through hole 5, and the first through hole 4. Therefore, the optical fiber 21 is securely fixed to the adhesive reservoir 6 and the second through-hole 5, and the optical fiber cable 20 is securely fixed to the first through-hole 4 so that the optical fiber 21 is stably held and the ferrule 1 is polished. Since the optical fiber 21 is held in a more stable state by the adhesive 11 of the adhesive reservoir 6 having a diameter larger than that of the second through-hole 5 in the vicinity of the front end of the optical fiber 21, damage such as cracking or chipping is caused in the optical fiber 21 during polishing. Can be effectively prevented. In addition, since the adhesive 11 is injected and filled in the adhesive reservoir 6 when the adhesive is injected into the first and second through holes 4 and 5, the production efficiency is not greatly reduced. Also, the adhesive reservoir 6 Since the size and shape of these are also determined in advance, the quality of the optical fiber mounting ferrule 30 after polishing can be stabilized.

  Therefore, an optical connector 32 capable of good optical coupling is obtained by inserting and fixing the optical fiber mounting ferrule 30 into a connector housing 31 as shown in FIG. 4, for example.

DESCRIPTION OF SYMBOLS 1 Ferrule 4 1st through-hole 5 2nd through-hole 6 Adhesive reservoir part 10a Discharge nozzle 11 Adhesive 20 Optical fiber cable 21 Optical fiber 30 Optical fiber installation ferrule 31 Connector housing 32 Optical connector

Claims (7)

A first through hole for penetrating the optical fiber cable and a second through hole for penetrating the optical fiber protruding from the front end of the coating of the optical fiber cable are provided continuously along the central axis of the ferrule, and the second An adhesive reservoir portion which is continuous with the front end of the through hole and has a diameter larger than that of the second through hole is recessed in the front end of the ferrule,
After injecting the adhesive into the adhesive reservoir, the second through hole and the first through hole of the ferrule,
An optical fiber cable is passed through the first through hole and an optical fiber protruding from the front end of the coating of the optical fiber cable is passed through the second through hole and the adhesive reservoir to cure the adhesive. ,
Next, a method for manufacturing an optical fiber mounting ferrule, wherein the front end of the ferrule having an optical fiber penetrated and fixed to the adhesive reservoir is polished to expose the front end surface of the optical fiber.   A nozzle that discharges the adhesive from the tip is inserted to the vicinity of the front end of the first through hole, the adhesive is injected into the second through hole and the adhesive reservoir, and then the nozzle is pulled back while pulling out the nozzle. The method for manufacturing an optical fiber mounting ferrule according to claim 1, wherein an adhesive is injected into the first through hole.   The manufacturing method of the optical fiber mounting ferrule of Claim 1 or Claim 2 which uses the adhesive agent whose viscosity in 23 degreeC is 3000-6000 cPs as said adhesive agent.   The ferrule is formed of zirconia or liquid crystal polymer (LCP), and an adhesive whose hardness after curing is smaller than the hardness of the ferrule and the optical fiber is used as the adhesive. The manufacturing method of the optical fiber mounting ferrule of any one of these.   The adhesive reservoir has a substantially cylindrical shape or a substantially frustoconical shape that expands toward the front end, and passes through the optical fiber along the central axis of the adhesive reservoir, and is formed on the front end surface of the adhesive reservoir. 5. The diameter according to claim 1, wherein the diameter is three times or more of the diameter of the optical fiber, and the depth of the adhesive reservoir is three times or more of the diameter of the optical fiber. Manufacturing method of an optical fiber mounting ferrule.   An optical fiber mounting ferrule manufactured by the manufacturing method according to any one of claims 1 to 5.   An optical connector in which the optical fiber mounting ferrule according to claim 6 is inserted and held in a connector housing.

Images