JP2013160792A - Ferrule - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ferrule capable of preventing an adhesive from reaching the outside of a surface to be polished.SOLUTION: A ferrule 10 has a hole portion 19 in which a terminal of an optical fiber 30 is inserted, and the terminal of the optical fiber 30 inserted in the hole 19 is fixed with an adhesive 33. On a surface 13 to be polished which is polished after the terminal of the optical fiber 30 is fixed, a wall portion 25 surrounding a periphery of an opening 19A of the hole 19 is provided. Therefore, the adhesive 33 flowing out from the opening 19A of the hole portion 19 remains inside the wall portion 25, so that the adhesive 33 can be prevented from reaching the outside of the surface 13 to be polished.

Description

  The present invention relates to a ferrule in which an end of an optical fiber is fixed by an adhesive.

  Conventionally, as a ferrule to which an optical fiber terminal is fixed, an optical fiber terminal is inserted into a hole provided in the ferrule and fixed by an adhesive. For example, in the ferrule described in Patent Document 1 below, an optical fiber end is inserted and fixed in a hole filled with an adhesive in advance. Thereafter, the tip of the ferrule is polished so that the positions of the end face of the optical fiber and the end face of the ferrule are aligned.

JP 2008-9129 A

  By the way, when fixing an optical fiber to a ferrule, there exists a possibility that an adhesive will flow outside from a hole and may adhere to the outer surface of a ferrule and harden | cure. Here, when the adhesive adheres to the surface to be polished after fixing the optical fiber, the adhesive can be scraped off when polishing the ferrule. However, when the adhesive reaches the outside of the surface to be polished (the surface that is not polished), it is difficult to remove only the adhesive without cutting the ferrule, so the adhesive cannot be removed. If the adhesive remains attached to the outer surface of the ferrule, connection of the optical fiber may cause connection loss, for example, the ferrule does not match well and the optical axis shifts between the optical fibers. Therefore, measures were desired.

  This invention is completed based on the above situations, Comprising: It aims at providing the ferrule which can prevent an adhesive agent reaching the outer side of the surface to be polished.

  The ferrule of the present invention is a ferrule having a hole portion into which an end of an optical fiber is inserted, the end of the optical fiber inserted into the hole portion being fixed by an adhesive, and the end of the optical fiber being fixed A wall that surrounds the periphery of the opening of the hole is provided on the polished surface that is then polished. According to such a configuration, since the adhesive flowing out from the opening of the hole remains inside the wall, it is possible to prevent the adhesive from reaching the outside of the polishing surface.

  Moreover, the said wall part is good also as what is provided continuously over the perimeter of opening of the said hole part. According to such a configuration, for example, it is possible to more reliably prevent the adhesive from reaching the outside of the polishing surface as compared with a case where there is a break in the wall portion.

Moreover, the said wall part is good also as what is provided along the boundary of the said grinding | polishing surface and the surface of the outer side. According to such a configuration, for example, it is possible to retain more adhesive on the inner side of the wall portion than when the wall portion is provided on the inner side of the boundary between the polishing surface and the outer surface. Therefore, it is possible to more reliably prevent the adhesive from reaching the outside of the polishing surface.
Moreover, the said wall part is good also as what is made into the shape which becomes thin toward the front end side. According to such a structure, a wall part can be shaved easily.

  According to the present invention, it is possible to provide a ferrule capable of preventing the adhesive from reaching the outside of the surface to be polished.

The side view which shows the state after it is a ferrule in this embodiment, and a grinding | polishing surface was grind | polished Cross section of the ferrule showing the state after the polished surface has been polished Partial enlarged sectional view of the ferrule showing the state before the polished surface is polished Partially enlarged front view of the ferrule showing the state before the polished surface is polished Partial enlarged sectional view of the ferrule showing the state where the adhesive is kept inside the wall Partial enlarged sectional view of the ferrule showing the state after the polished surface has been polished

Hereinafter, an embodiment embodying the present invention will be described in detail with reference to FIGS.
The ferrule 10 in this embodiment is a ferrule for an optical connector used mainly for an optical communication connector of various electrical components mounted on an automobile, and has a function of holding the end of the optical fiber 30.

  The optical fiber 30 is made of a member that propagates an optical signal, and is a known one that includes a core and a clad formed outside the core. The outer periphery of the optical fiber 30 is covered with a protective coating 31, and the optical fiber 30 with the protective coating 31 covered is referred to as an optical fiber core wire 32. The optical fiber 30 is exposed from the protective coating 31 at the tip of the optical fiber core wire 32.

  The ferrule 10 is made of synthetic resin and has a shape that is long in the front-rear direction as a whole. The ferrule 10 includes a main body portion 11 that is inserted into a cylindrical portion or the like of an optical connector (not shown) and is brought into contact with the counterpart ferrule 10, and a terminal portion 12 that is disposed on the outside of the cylindrical portion or the like. These are integrally formed by injecting molten resin into the mold. When the pair of optical connectors are fitted, the main body portion 11 of one ferrule 10 and the main body portion 11 of the other ferrule 10 are abutted inside the cylindrical portion or the like, and the optical fiber 30 is optically connected. .

The main body 11 of the ferrule 10 has a substantially cylindrical shape as a whole. The main body 11 has a tapered shape only at the tip, and the diameter of the rear part of the body 11 is constant.
The front end surface of the ferrule 10 is a polishing surface 13 that is polished after the end of the optical fiber 30 is fixed (see FIG. 3). The polishing surface 13 is a flat surface that is perpendicular to the axis of the main body 11. The polishing surface 13 has a circular shape, and an opening 19 </ b> A of a hole 19 described later is formed at the center thereof. The polishing surface 13 is provided with a wall portion 25. The wall portion 25 will be described in detail later.

  By polishing the polishing surface 13, a facing surface 14 that faces the counterpart ferrule 10 is formed (see FIG. 6 and the like). Like the polishing surface 13, the facing surface 14 is a flat surface that is perpendicular to the axis of the main body 11 and has a circular shape, and a hole 19 described later is formed at the center thereof. The facing surface 14 and the end surface of the optical fiber 30 are in a state of being aligned by polishing (a state of being flush with each other).

  A portion of the front end portion of the ferrule 10 on the rear side of the polishing surface 13 is a tapered portion 15 whose diameter (width size) gradually increases from the polishing surface 13 toward the rear side. And the outer peripheral surface of the taper part 15 is made into the taper surface 16 which makes | forms the inclination which leaves | separates little by little from the axis line of the main-body part 11 toward the back side from the grinding | polishing surface 13. FIG. The tapered surface 16 is formed around (outside) the polishing surface 13 and has a constant inclination over the entire circumference.

  The end portion 12 of the ferrule 10 has a flange portion 17 having a shape protruding outward in the radial direction from the main body portion 11 (see FIG. 1). The flange portion 17 is disposed in front of a coil spring (not shown) provided in the optical connector, and the ferrule 10 is biased forward (on the other side) when the flange portion 17 receives the elastic force of the coil spring. The front end surface and the rear end surface of the flange portion 17 are both perpendicular to the axis of the ferrule 10.

  On the rear side of the flange portion 17, a shaft portion 18 on which the coil spring is fitted is erected. The shaft portion 18 has a columnar shape protruding rearward from the center of the flange portion 17. The flange portion 17 has a quadrangular cross section, the shaft portion 18 has a polygonal cross section, and the center lines of the main body portion 11 and the end portion 12 coincide.

  Inside the ferrule 10 is provided a hole 19 into which the end of the optical fiber 30 is inserted (see FIG. 2). The end of the optical fiber 30 inserted into the hole 19 is fixed by a thermosetting adhesive 33.

  The hole portion 19 has a circular cross section and is formed so as to penetrate the ferrule 10 in the front-rear direction. The hole 19 extends linearly along the axis of the ferrule 10, and one end thereof opens to the center of the polishing surface 13 of the main body 11, and the other end opens to the center of the rear end surface of the shaft 18. .

  The diameter of the hole portion 19 is different between the front end portion, the intermediate portion, and the rear end portion of the ferrule 10. Specifically, the diameter of the hole 19 is the smallest at the front end of the ferrule 10 and the largest at the rear end. The front end portion (minimum diameter portion) of the hole 19 is referred to as a fiber holding portion 21, the intermediate portion is referred to as a core wire holding portion 22, and the rear end portion (maximum diameter portion) is referred to as a large diameter portion 23. The hole diameter of the core wire holding portion 22 is set to be substantially the same as the outer diameter size of the optical fiber core wire 32.

  The optical fiber 30 is inserted into the hole 19 from the rear (from the large diameter portion 23 side). Then, the optical fiber 30 is disposed on the fiber holding portion 21, and the optical fiber core wire 32 is disposed on and fixed to the core wire holding portion 22 and the large diameter portion 23 (see FIG. 2). The end of the optical fiber 30 is fixed to the ferrule 10 by the optical fiber 30 being bonded and fixed at least at the fiber holding portion 21. In this embodiment, the optical fiber core wire 32 is also bonded and fixed at the core wire holding portion 22 and the large diameter portion 23.

  The portion of the hole 19 where the diameter dimension changes, that is, the portion between the fiber holding portion 21 and the core wire holding portion 22 and the portion between the core wire holding portion 22 and the large diameter portion 23 are from the rear side to the front side. The guide unit 24 guides the optical fiber 30. The guide portion 24 has a shape that is inclined so that the diameter is gradually reduced from the rear side toward the front side. Due to the inclination of the guide portion 24, the optical fiber 30 inserted into the hole portion 19 is guided to the center side of the hole portion 19 and smoothly advances through the hole portion 19.

  Now, the polishing surface 13 of the ferrule 10 is provided with a wall portion 25 surrounding the periphery of the opening 19A of the hole portion 19 (see FIGS. 3 and 4). The wall portion 25 is formed in an annular shape that is continuous without interruption throughout the entire circumference of the opening 19A of the hole portion 19. The wall portion 25 is provided on the boundary between the polishing surface 13 and the tapered surface 16.

  The wall portion 25 has substantially the same cross-sectional shape continuous over the entire circumference. The wall portion 25 has a shape that becomes thinner toward the distal end side (the wall thickness dimension becomes smaller), and has the largest wall thickness dimension at the base and the smallest wall thickness dimension at the distal end. The tip of the wall 25 is sharp.

  Both the inner peripheral surface 26 and the outer peripheral surface 27 of the wall portion 25 are inclined so as to fall outside the perpendicular to the polishing surface 13. Note that the outer peripheral surface 27 of the wall portion 25 is closer to the vertical than the inner peripheral surface 26.

  A circular recess 28 is formed inside the wall 25. The hollow portion 28 has a shape in which the diameter dimension gradually increases from the bottom surface (polishing surface 13) toward the open side.

Next, an example of fixing work for fixing the terminal of the optical fiber 30 to the ferrule 10 will be described.
First, the adhesive 33 is injected into the hole 19. The ferrule 10 is fixed in such a posture that the opening 19B (large diameter portion 23) on the rear side of the hole 19 faces upward, and the adhesive 33 is injected from the opening 19B on the rear side. The adhesive 33 does not reach the fiber holding portion 21 but stops at the front guide portion 24 and is filled from the core wire holding portion 22 to the large diameter portion 23. Since the opening 19B on the rear side of the hole 19 has a larger opening size than the opening 19A on the front side, the adhesive 33 can be easily injected, and air bubbles are prevented from being generated in the adhesive 33. can do.

  Next, the optical fiber 30 is inserted into the hole 19. The optical fiber 30 is put in an adhesive 33 filled in the hole 19, and the adhesive 33 adheres to the surface thereof. Eventually, the optical fiber 30 reaches the fiber holding part 21, passes through the fiber holding part 21, and is drawn forward from the polishing surface 13. At this time, the adhesive 33 attached around the optical fiber 30 is pushed out of the hole 19 while being applied to the fiber holding portion 21. Further, the optical fiber core wire 32 is arranged from the core wire holding portion 22 to the large diameter portion 23, and is stopped at the normal insertion position by the guide portion 24.

  Next, the adhesive 33 is cured. When heated by a heater (not shown), the viscosity of the adhesive 33 decreases, flows through the hole 19 downward, and eventually flows out from the opening 19A of the hole 19 outside. The adhesive 33 that has flowed out from the hole 19 spreads along the polishing surface 13, and when this happens, the wall 25 restricts further spread and accumulates in the recess 28 to form a lump (see FIG. 5). . Further, the adhesive 33 is cured by further heating, the optical fiber 30 and the optical fiber core wire 32 are bonded to the hole 19, and the end of the optical fiber 30 is fixed to the ferrule 10.

  Thereafter, the polishing surface 13 is polished to form the facing surface 14. The optical fiber 30 drawn forward from the ferrule 10 is cut, and the wall portion 25 and the adhesive 33 solidified inside thereof are scraped off. The wall portion 25 is gradually shaved from the tip, and eventually the whole is shaved off. Further, all the adhesive 33 inside the wall portion 25 is also scraped off, and the polished surface 13 is exposed. And the edge part of the optical fiber 30 and the grinding | polishing surface 13 are grind | polished, the end surface of the optical fiber 30 and the end surface of the ferrule 10 are aligned, and the opposing surface 14 is formed (refer FIG. 6). Thus, the fixing operation of the optical fiber 30 is completed.

According to the present embodiment configured as described above, the following effects can be obtained.
The ferrule 10 of the present embodiment is a ferrule 10 that has a hole portion 19 into which an end of an optical fiber 30 is inserted, and the end of the optical fiber 30 inserted into the hole portion 19 is fixed by an adhesive 33. A wall 25 surrounding the periphery of the opening 19A of the hole 19 is provided on the polishing surface 13 to be polished after the end of the fiber 30 is fixed. Thereby, since the adhesive 33 flowing out from the opening 19 </ b> A of the hole portion 19 stays inside the wall portion 25, it is possible to prevent the adhesive 33 from reaching the outside (tapered surface 16) of the polishing surface 13.

  Here, the amount of the adhesive flowing out from the hole increases, for example, when the fiber holding part is short or when the fiber holding part has a large diameter, so that the fiber holding part is lengthened or the diameter dimension is reduced. It is conceivable to reduce the amount of adhesive flowing out. However, doing so may make it difficult to insert the optical fiber. In addition, while conventional ferrules have mainly used zirconia ceramics as a material, synthetic resins are sometimes used to reduce costs. The ferrule made of synthetic resin is more likely to adhere to the surface than the conventional (high wettability), so the adhesive is likely to spread from the polished surface to the taper surface or the side surface behind it, In addition, since it is softer than zirconia ceramics, it is more difficult to scrape off the adhesive alone. In this regard, in the ferrule 10 of the present embodiment, the polishing surface 13 that is polished after the end of the optical fiber 30 is fixed is provided with the wall portion 25 that surrounds the opening 19A of the hole portion 19. The agent 33 can be prevented from reaching the outside of the polishing surface 13 (tapered surface 16), which is particularly advantageous.

  The wall portion 25 is provided continuously over the entire circumference of the opening 19 </ b> A of the hole portion 19. Thereby, for example, the adhesive 33 can be more reliably prevented from reaching the outside of the polishing surface 13 as compared with a case where there is a break in the wall portion.

The wall portion 25 is provided along the boundary between the polishing surface 13 and the outer tapered surface 16. Thus, for example, more adhesive 33 can be retained inside the wall portion 25 than when the wall portion is provided inside the boundary between the polished surface and the tapered surface. It is possible to more reliably prevent 33 from reaching the outside of the polishing surface 13.
Moreover, since the wall part 25 is made into the shape which becomes thin toward the front end side, the wall part 25 can be shaved easily.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
(1) In the above embodiment, an example in which the present invention is applied to an in-vehicle optical connector ferrule has been described. However, the present invention can be widely applied to ferrules used for other purposes.
(2) In the said embodiment, although the example which applied this invention to the ferrule 10 made from a synthetic resin was shown, this invention is applicable also to the ferrule made from ceramics, for example.
(3) In the above embodiment, the polishing surface 13 and the facing surface 14 are flat surfaces that are perpendicular to the axis of the main body 11, but what is the shape of the tip of the ferrule? Alternatively, the polishing surface and the facing surface may be, for example, an inclined surface that is inclined with respect to the axis of the main body or a spherical surface.

(4) In the above embodiment, the wall portion 25 is continuously provided over the entire circumference of the opening 19A of the hole portion 19; however, the wall portion is not limited thereto, and for example, the wall portion is large enough to prevent the adhesive from passing therethrough. It may have a slit.
(5) In the said embodiment, although the wall part 25 is provided on the boundary of the grinding | polishing surface 13 and the taper surface 16, it is not restricted to this, For example, a wall part is a boundary with a taper surface among grinding | polishing surfaces. And may be provided around the center between the opening of the hole portion.
(6) In the said embodiment, although the wall part 25 is made into the annular | circular shape, it is not restricted to this, For example, the wall part may be made into square frame shape.
(7) In the said embodiment, although the wall part 25 is made into the shape which becomes thin toward the front end side, it is not restricted to this, For example, a wall part has a constant wall thickness dimension from a root to a front end. Alternatively, it may be thicker from the root side toward the tip side.

10 ... Ferrule 16 ... Tapered surface (outer surface)
DESCRIPTION OF SYMBOLS 19 ... Hole 19A ... Opening of hole 25 ... Wall 30 ... Optical fiber 33 ... Adhesive

Claims (4)

A ferrule having a hole into which an end of an optical fiber is inserted, and the end of the optical fiber inserted into the hole being fixed by an adhesive;
A ferrule in which a wall portion surrounding the opening of the hole portion is provided on a polishing surface to be polished after the end of the optical fiber is fixed.   The ferrule according to claim 1, wherein the wall portion is continuously provided over the entire circumference of the opening of the hole portion.   The ferrule according to claim 1, wherein the wall portion is provided along a boundary between the polishing surface and an outer surface thereof.   The ferrule according to any one of claims 1 to 3, wherein the wall portion has a shape that becomes thinner toward a tip end side thereof.

Images