JP2006053283A - Optical connector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-cost optical connector which makes a plastic clad optical fiber connectable at or below a desired connection loss. <P>SOLUTION: A plug connector 20 has a built-in ferrule 21 that holds an optical fiber 2 projectingly from the end face of the ferrule 21. A receptacle connector 10 has a built-in ferrule 11 that hold an optical fiber 1 retractively from the end face of the ferrule 11 with a distance shorter than the projecting length of the optical fiber 2. By fitting the plug connector 20 and the receptacle connector 10 to each other, the element wire 2a at the projected tip end of the optical fiber 2 is inserted into the ferrule 11 to come in press-contact with the element wire 1a of the optical fiber 1. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an inexpensive optical connector suitable for connecting plastic clad optical fibers.

In recent years, with the progress of computerization of automobiles, optical fibers capable of transmitting large volumes of information have been used as information transmission media in vehicles, and many plastic optical fibers whose cores and clads are made of plastic are used. in use. A plastic optical fiber has a larger transmission loss than a glass optical fiber, but is suitable for short-distance communication in a vehicle in that it is inexpensive and easy to handle. The optical connection of the plastic optical fiber is performed using an optical connector in which the ferrules into which the optical fibers are inserted and held are aligned, and the optical fibers are brought into contact with each other at the end face of the ferrule (for example, see Patent Document 1). .)
Optical fibers in vehicles are required to be used in a severe temperature environment such as an engine room from the conventional indoor environment. Further, when used in tying with a wire harness having a complicated routing shape, it is required that transmission loss is small with a small bending radius.
Therefore, use of a plastic clad optical fiber in a vehicle, which can be used at a higher temperature than a plastic optical fiber and has a small bending loss, has been studied. In addition, in order to use in a large amount for vehicles and the like, an optical connector for a plastic clad optical fiber is required to have a connection loss that is less than a desired value and can be manufactured at a low cost.
The plastic clad optical fiber is an optical fiber having a core made of quartz and a clad made of plastic, and is positioned between the glass optical fiber and the plastic optical fiber.
JP 2002-190344 A

However, since the plastic clad optical fiber has a strand diameter of about 0.23 mm and is smaller than the strand diameter of the plastic optical fiber (about 1 mm), the influence of the axis deviation on the connection loss is large, and the conventional plastic optical fiber When the optical connector for use is used, there is a problem that connection loss increases.
In order to reduce the connection loss of plastic clad optical fiber, it is conceivable to use an optical connector with a built-in ferrule with high dimensional accuracy, such as used for connecting a glass optical fiber for long-distance optical transmission. Such an optical connector has a problem of high cost. In addition, optical connectors that connect multiple plastic clad optical fibers at once require high dimensional accuracy for components other than ferrules, so the components used in conventional optical connectors for plastic optical fibers are applicable. The cost of parts other than the ferrule is high.

  In view of the above-described problems, an object of the present invention is to provide a low-cost optical connector that can suppress the connection of a plastic clad optical fiber to a desired connection loss or less.

  The present invention has been achieved as a result of intensive studies to achieve the above object, and the invention according to claim 1 has a receptacle connector and a plug connector fitted to the receptacle connector, and the receptacle connector. And one of the plug connectors incorporates a first ferrule that holds the optical fiber so as to protrude from the end face of the ferrule, and the other of the receptacle connector and the plug connector pulls the optical fiber from the end face of the ferrule. A second ferrule having a sleeve portion that holds and guides the first ferrule at the end is built in, and the first ferrule is attached to the second ferrule by fitting the plug connector and the receptacle connector. The end portion of the first ferrule is guided by the sleeve portion of the first ferrule and comes into contact with the second ferrule. The retained optical fiber so as to protrude Ri is inserted into a second ferrule, an optical connector, characterized in that the combined second optical fiber and the shaft which is held to pull from the end face of the ferrule.

  According to a second aspect of the present invention, in the first aspect of the invention, the second ferrule is shorter than the protruding length of the optical fiber held so as to protrude from the end face of the first ferrule. By holding the optical fiber so as to be drawn from the end face of the ferrule and fitting the plug connector and the receptacle connector, the optical fiber held by the first ferrule and the optical fiber held by the second ferrule are pressed. The optical fiber held by the second ferrule is an optical connector characterized in that it can be pressed and bent.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the second ferrule is provided with an opening that is widened at an end face, and an insertion hole that holds an optical fiber connected to the opening. The optical fiber held so as to protrude from the end face of the first ferrule by fitting the plug connector and the receptacle connector is provided in the end portion of the second ferrule. An optical connector inserted into the insertion hole from the opening and held so as to be drawn from the end face of the second ferrule is pressed and bent in the cavity.

  Furthermore, the invention according to claim 4 is the invention according to claim 1, 2 or 3, wherein the first ferrule has a length equal to or longer than the protruding length of the optical fiber at the end, A light having a cylindrical portion surrounding the protruding portion of the optical fiber, and the second ferrule has an annular groove into which the cylindrical portion of the first ferrule is inserted in an end surface of the sleeve portion. It is a connector. The annular groove provided on the end face of the second ferrule has a depth greater than or equal to the length of the cylindrical portion.

  According to the first aspect of the present invention, the first ferrule is guided by the sleeve portion of the second ferrule, contacts the second ferrule, and is held so as to protrude from the end face of the first ferrule. Is inserted into the second ferrule and aligned with the optical fiber held so as to be drawn from the end face of the second ferrule. Therefore, in the present invention, in order to realize a desired connection loss, it is not necessary to accurately align and abut the optical fibers inserted into the pair of ferrules as in the past, and the ferrule and other components The dimensional accuracy can be relaxed.

  According to the second aspect of the present invention, the optical fiber held by the first ferrule and the optical fiber held by the second ferrule are in pressure contact, and the optical fiber held by the second ferrule is pressed. Therefore, the optical fiber held by the first ferrule and the optical fiber held by the second ferrule can make a stable pressure-contact connection with elasticity.

  According to a third aspect of the present invention, since the second ferrule has an opening that is widened on the end face, the optical fiber held so as to protrude from the end face of the first ferrule is provided. The operation of inserting into the second ferrule is facilitated. In addition, since the second ferrule is provided with a hollow portion having an enlarged diameter at the end portion of the insertion hole that holds the optical fiber connected to the opening, the optical fiber held by the second ferrule is the first ferrule. When pressed against the optical fiber held by the ferrule, the cavity can be bent and elastically and stably press-connected.

  According to a fourth aspect of the present invention, the first ferrule has a cylindrical portion surrounding the optical fiber that is the same length or longer than the protruding length of the optical fiber at the end. The protruding portion of the optical fiber held by the first ferrule is protected by the cylindrical portion so that an external force or the like is not applied during handling.

According to the first aspect of the present invention, in order to connect an optical fiber having a diameter smaller than that of a plastic optical fiber with a desired connection loss, the dimensional accuracy of the ferrule and other components can be made looser than before. There is an advantage that the cost can be reduced.
Further, the invention according to claim 2 has an advantage that the optical fibers can be stably pressure-connected.
Further, the invention described in claim 3 is advantageous in that the connection work is facilitated and a stable pressure connection can be realized with elasticity.
Furthermore, the invention described in claim 4 has an advantage that the protruding portion of the optical fiber held by the first ferrule can be protected from an external force.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.
FIG. 1 is a perspective view of an embodiment of an optical connector according to the present invention. 2 (a) and 2 (b) are a cross-sectional view of the receptacle connector of the embodiment and a cross-sectional view of a plug connector fitted to the receptacle connector, respectively. 3A, 3B, and 3C are a cross-sectional view of a ferrule built into the receptacle connector, a cross-sectional view of the ferrule built into the plug connector, and AA in FIG. 3B, respectively. It is sectional drawing. Further, FIG. 4 is a cross-sectional view of a state in which the ferrule built in the receptacle connector and the ferrule built in the plug connector are fitted and connected.

  As shown in FIG. 1, the optical connector according to the present embodiment includes a receptacle connector 10 and a plug connector 20. The receptacle connector 10 and the plug connector 20 are fitted by inserting the plug connector housing 22 into the receptacle connector housing 13 and locking the locking claws 22a of the plug connector housing 22 into the locking holes 13a of the receptacle connector housing 13. .

As shown in FIG. 2A, the receptacle connector 10 has a built-in ferrule 11 formed by cutting brass. The ferrule 11 is fixed in the sub-housing 12 with the flange portion 11f pressed by a spring 15 interposed between the ferrule 11 and the sub-housing 12 is fixed in the receptacle connector housing 13.
Further, the plug connector 20 has a ferrule 21 formed of resin built in a plug housing 22 as shown in FIG.

As shown in FIG. 3A, the ferrule 11 has a sleeve portion 11a into which the tip of the ferrule 21 is inserted, and an end portion 11b in the sleeve portion 11a is provided with an opening 11b that expands in a tapered shape. In addition, an annular groove 11g is provided so as to surround the opening 11b. Furthermore, an insertion hole 11c for holding the optical fiber 1 is provided so as to be continuous with the opening 11b, and an enlarged cavity 11d is provided at an end of the insertion hole 11c.
The optical fiber 1 held by the ferrule 11 is inserted into the insertion hole 11c so that the end of the strand 1a from which the coating has been peeled is drawn from the end face of the ferrule 11 by a distance L2, and the fixing portion 11e of the ferrule 11 is caulked. By this, it is fixed by the covering portion 1b.

The ferrule 21 is provided with an insertion hole 21a for holding the optical fiber 2 as shown in FIG. Further, at the end of the ferrule 21, a cylindrical portion 21c longer than L1 described later is provided so as to surround the insertion hole 21a.
The optical fiber 2 held by the ferrule 21 is inserted into the insertion hole 21a and held by the clamp 23 so that the end of the strand 2a from which the coating has been peeled is projected from the end face of the ferrule 21 with a projection length L1. . The protruding length L1 is set to be longer than the distance L2 (in other words, the distance L2 is shorter than L1).
As shown in FIG. 3C, the clamp 23 is formed in a U-shape with resin, and is formed so that a plurality of grooves 23 a that form irregularities on the inner surface are orthogonal to the longitudinal direction. The covering portion 2b of the optical fiber 2 is sandwiched and fixed by being press-fitted from the opening portion 21b.

The optical fiber 1 and the optical fiber 2 are connected by fitting the plug connector housing 22 into the receptacle connector housing 13 and inserting the distal end portion of the ferrule 21 into the sleeve portion 11a of the ferrule 11 as shown in FIG. , 12 are relatively positioned, and the end surfaces of the ferrule 11 and the ferrule 21 are brought into contact with each other. At this time, the cylindrical portion 21c of the ferrule 21 is fitted into the annular groove 11g of the ferrule 11, and the ferrule 11 and the ferrule 21 are pressed by the spring 15 (see FIG. 2A). In addition, since the annular groove 11g has a depth greater than the length of the cylindrical portion 21c, the tip of the cylindrical portion 21c does not hit the bottom of the annular groove 11g.
The strand 2a of the optical fiber 2 protruding from the end face of the ferrule 21 by a length L1 is inserted into the insertion hole 11c from the opening 11b of the ferrule 11, and is drawn from the end face of the ferrule 11 by a distance L2 (<L1). The fiber 1 is pressed against the strand 1a. The element wire 1a is pressed by the element wire 2a, retreats by L1-L2 in the insertion hole 11c, and is bent in the cavity portion 11d.

The feature of this embodiment that is different from the conventional example is that the ferrule 21 built in the plug connector 20 protrudes from the end face of the ferrule 21 with a protruding length L1 of the strand 2a from which the coating of the tip of the optical fiber 2 is peeled off. Further, the ferrule 11 built in the receptacle connector 10 removes the strand 1a from which the coating of the tip of the optical fiber 1 is peeled from the end face by a distance L2 shorter than the protruding length L1 of the optical fiber 1. It is holding it so that it pulls in. Then, by fitting the plug connector 20 into the receptacle connector 10, the ferrule 21 is guided in the sleeve portion 11 a of the ferrule 11, the ferrule 11 and the ferrule 21 abut, and protrudes from the end face of the ferrule 21. The strand 2a of the optical fiber 2 held so as to be inserted is inserted into the insertion hole 11c of the ferrule 11 and pressed against the strand 1a of the optical fiber 1 held so as to be drawn from the end face of the ferrule 11.
Therefore, in this embodiment, the optical fibers 1 and 2 are axially aligned in the insertion hole 11c and optically connected in a pressed state. Therefore, the conventional optical connection (the alignment of the opposing ferrules allows the ferrule In order to realize a desired connection loss as in the case of the connection in which the optical fibers are in contact with each other at the end faces, it is not necessary to accurately align and contact the optical fibers inserted into the pair of ferrules. 21 and other component parts can be relaxed.

Another feature of the present embodiment that differs from the conventional example is that the ferrule 11 has an opening 11b that is widened on the end face, and the end of the insertion hole 11c that holds the optical fiber 2 that is continuous with the opening 11b. This is that a hollow portion 11d having an enlarged diameter is provided in the portion.
Therefore, in the present embodiment, by bringing the ferrule 11 and the ferrule 21 into contact with each other, the strand 2a of the optical fiber 2 that is held protruding from the end face of the ferrule 21 is guided by the opening 11b whose tip is expanded. And is easily inserted into the insertion hole 11c. Further, a hollow portion 11d having an enlarged diameter is provided at the end of the insertion hole 11c of the ferrule 11, and the strand 1a of the optical fiber 1 held so as to be drawn from the end face of the ferrule 11 is the strand of the optical fiber 2. 2a is pushed back by the inside of the insertion hole 11c and is flexibly elastically deformed by the hollow portion 11d, so that the connection loss due to the bending of the strands 1a and 2a is prevented by the pressure contact between the strands 1a and 2a. Can do.

Still another characteristic feature of the present embodiment that differs from the conventional example is that the ferrule 21 is provided with a cylindrical portion 21c at the end that is longer than the protruding length of the optical fiber 2 and that surrounds the protruding portion of the optical fiber 2. The ferrule 11 is provided with an annular groove 11g into which the cylindrical portion 21c of the ferrule 21 is inserted on the end surface in the sleeve portion 11a.
Therefore, in this embodiment, the protrusion part of the optical fiber 2 can be protected from external force by the cylinder part 21c. When the ferrule 11 and the ferrule 21 are brought into contact with each other at the end face, the cylindrical portion 21c of the ferrule 21 is inserted into the annular groove 11g of the ferrule 11, so that the contact between the end faces of the ferrule 11 and the ferrule 21 is obstructed. There is no.

(Example)
The optical fibers 1 and 2 are plastic clad optical fibers in which the diameters A of the strands 1a and 2a are 0.23 + 0 / −0.01 mm, and the dimensions and tolerances of the ferrules 11 and 21 are set as follows (FIG. 3).
About ferrule 11,
Hole diameter B1 of the insertion hole 11c: 0.27 ± 0.03 mm
Inner diameter C1 of the sleeve portion 11a: 2.95 ± 0.03 mm
Eccentricity of inner diameter of insertion hole 11c and sleeve portion 11a: smaller than 0.05 mm About ferrule 21
Hole diameter B2 of the insertion hole 21a: 0.27 ± 0.03 mm
Outer diameter C2: 2.90 ± 0.05 mm
Insertion hole 21a and eccentricity of outer diameter: smaller than 0.05 mm Further, an opening 11b widened by a taper of 45 ° is provided on the inner end surface of the sleeve part 11a of the ferrule 11, and the insertion hole 11c connected to the opening 11b. A cavity portion 11d having a diameter increased in a tapered shape is provided between the opposite end portion and the fixed portion 11e. Further, the ferrule 21 is provided with a cylindrical portion 21c having a length of 1 mm, and the ferrule 11 is provided with an annular groove 11g having a depth of 1 mm or more.

  The strand 2a of the optical fiber 2 is fixed so that the protruding length L1 is 0.8 mm from the end face of the ferrule 21 (a range that does not protrude from the end face of the plug connector housing 22). 1a is fixed in a state where it is drawn from the end face of the ferrule 11 by a distance L2 = 0.5 mm. Accordingly, the ferrule 21 is inserted into the sleeve portion 11a of the ferrule 11, the end surfaces of the ferrule 21 and the ferrule 11 abut, the protruding portion of the strand 2a is inserted into the insertion hole 11c, and the strand 1a and the strand 2a are In the pressed state, the strand 1a is pushed by the strand 2a, retreats by a length of 0.3 mm (= 0.8−0.5), and bends in the hollow portion 11d.

In the present embodiment, the strand 1a of the optical fiber 1 and the strand 2a of the optical fiber 2 are pressed and connected in the insertion hole 11c of the ferrule 11. The axial misalignment between the strands 1a and 2a in the insertion hole 11c is maximum when the hole diameter B1 of the insertion hole 11c is the upper limit value and the diameter A of the strands 1a and 2a is the lower limit value. Is 0.08 mm (= (0.27 + 0.03)-(0.23-0.01) / 2- (0.23-0.01)) / 2).
On the other hand, the connection loss of the optical fiber in the vehicle is usually required to be 2.5 dB or less, and for that purpose, the axis deviation of the plastic clad optical fiber to be connected should be 0.08 mm or less. Has been demonstrated. Therefore, in this embodiment, the plastic clad optical fiber can be connected with a desired connection loss or less.
The ferrules 11 and 21 have the same dimensional accuracy as that of a conventional plastic optical fiber connector, and the cost is not particularly increased. Further, parts (sub-housing 12, receptacle connector housing 13, plug connector housing 22, etc.) other than ferrules 11 and 21 constituting receptacle connector 10 and plug connector 20 should be equivalent to plastic optical fiber connectors. The cost will not increase in particular.
Further, the strand 2a of the optical fiber 2 held by the ferrule 21 is deviated from the insertion hole 11c and the inner diameter of the sleeve portion 11a with respect to the insertion hole 11c of the ferrule 11, and outside the insertion hole 21a of the ferrule 21 and the ferrule 21. There is a possibility that the axis is displaced by about 0.20 mm including the eccentricity of the diameter. However, since the ferrule 11 is provided with the opening 11b, the strand 2a is easily guided to the insertion hole 11c by the opening 11b. Inserted.
Further, since the ferrule 21 is provided with the cylindrical portion 21c having a length of 1 mm, the strand 2a protruding from the end face by the protruding length L1 = 0.8 mm can be protected.

(Conventional example)
As a conventional connection structure, in FIG. 3, the ferrule 11 is not provided with the opening 11b and the cavity 11d, the end surface of the strand 1a of the optical fiber 1 is made to coincide with the end surface of the ferrule 11, and the strand of the optical fiber 2 2a The front end surface is made to coincide with the end surface of the ferrule 21. Then, the ferrule 21 is inserted into the sleeve portion 11a of the ferrule 11, the ferrule 11 and the ferrule 21 are brought into contact with each other at the end faces, and the strand 1a and the strand 2a are brought into contact with each other to be optically connected.
In this case, in order to make the axial misalignment between the optical fiber 1 and the optical fiber 2 in which the diameters of the strands 1a and 2a are 0.23 + 0 / −0.01 mm at most 0.08 mm or less, the dimensions B1, C1, It is necessary to set the dimensional tolerances of B2 and C2 and the eccentricity to an order of magnitude smaller than the above-described conventional values.
Therefore, an optical connector for connecting an optical fiber (for example, a plastic clad optical fiber) in which the diameters of the strands 1a and 2a are about 0.23 mm with a desired connection loss with a conventional connection structure is low in productivity and cost. To rise.

  Incidentally, in the above-described conventional connection structure, in the case of a plastic fiber having a diameter larger than that of the plastic clad optical fiber in which the diameters of the strands 1a and 2a are 1.00 ± 0.04 mm, the dimensions B1, C1, By setting the dimensional tolerances of B2 and C2 and the eccentricity to the above-mentioned conventional values, the maximum value of the axis deviation (0.45 mm) for obtaining a desired connection loss of 2.5 dB can be realized.

In the above embodiment, the optical fibers 1 and 2 are plastic clad optical fibers, but it goes without saying that they may be glass optical fibers.
Moreover, in the said Example, although the ferrule 11 was formed by metal cutting, you may shape | mold with resin and may fix the optical fiber 1 with a clamp or an adhesive agent. Moreover, although the ferrule 21 was shape | molded with resin and was fixed with the clamp 23, you may form by metal cutting.
Further, the cylindrical portion 21c of the ferrule 21 and the annular groove 1g of the ferrule 11 need not be provided. In this case, the protruding length L1 of the strand 2a from the end face of the ferrule 21 is such that the protruding portion of the strand 2a is accommodated in the plug connector housing 22 in a state where the ferrule 21 is fixed in the plug connector housing 22. It is preferable to set.
Further, the ferrule 11 may be built in the plug connector 20 and the ferrule 21 may be built in the receptacle connector 10.

It is a perspective view of one embodiment of an optical connector concerning the present invention. (A) And (b) is sectional drawing of the receptacle connector of the said embodiment, respectively, and sectional drawing of a plug connector. (A), (b), and (c) are the sectional view of the ferrule built in the receptacle connector of the said embodiment, the sectional view of the ferrule built in the plug connector, respectively, and AA of FIG.3 (b) It is sectional drawing. In the said embodiment, it is sectional drawing of the state which the ferrule built in the receptacle connector and the ferrule built in the plug connector fitted and contact | abutted.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2 Optical fiber 1a, 2a Wire 1b, 2b Covering part 10 Receptacle connector 11, 21 Ferrule 11a Sleeve part 11b Opening part 11c, 21a Insertion hole 11d Cavity part 11e Fixing part 11f Flange part 11g Annular groove 12 Sub housing 13 Receptacle Connector housing 13a Locking hole 14 Fixing plate 15 Spring 20 Plug connector 21b Opening 21c Tube part 22 Plug connector housing 22a Locking claw 23 Clamp 23a Groove

Claims (4)

A receptacle connector, and a plug connector that fits into the receptacle connector;
One of the receptacle connector and the plug connector incorporates a first ferrule that holds the optical fiber so as to protrude from the end face of the ferrule,
The other one of the receptacle connector and the plug connector holds the optical fiber so as to be drawn from the end face of the ferrule, and incorporates a second ferrule having a sleeve portion for guiding the first ferrule at the end,
By fitting the plug connector and the receptacle connector, the first ferrule is guided by the sleeve portion of the second ferrule, contacts the second ferrule, and is held so as to protrude from the end face of the first ferrule. An optical connector, wherein the optical fiber is inserted into a second ferrule and axially aligned with the optical fiber held so as to be drawn from the end face of the second ferrule. The second ferrule holds the optical fiber so as to be drawn from the end face of the ferrule at a distance shorter than the protruding length of the optical fiber held so as to protrude from the end face of the first ferrule,
By fitting the plug connector and the receptacle connector, the optical fiber held by the first ferrule and the optical fiber held by the second ferrule are in pressure contact, and the optical fiber held by the second ferrule is The optical connector according to claim 1, wherein the optical connector can be bent by being pressed. The second ferrule is provided with an opening that is widened at the end face, and is provided with a cavity that is enlarged in diameter at the end of the insertion hole that holds the optical fiber connected to the opening.
By fitting the plug connector and the receptacle connector, the optical fiber held so as to protrude from the end face of the first ferrule is inserted into the insertion hole from the opening of the second ferrule, and the second 3. The optical connector according to claim 1, wherein the optical fiber held so as to be drawn from the end face of the ferrule is pressed and bent in the cavity.   The first ferrule has a cylindrical portion at the end that has a length equal to or longer than the protruding length of the optical fiber, and surrounds the protruding portion of the optical fiber. 4. The optical connector according to claim 1, further comprising an annular groove into which the cylindrical portion of the first ferrule is inserted in an end surface of the sleeve portion.

Images