JP2002169059A - Ferrule for plastic optical fiber and optical connector equipped therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide such as ferrule for a plastic optical fiber that prevents generation of pistoning phenomenon and that suppresses deformation in termination, and also to provide an optical connector equipped with this ferrule. SOLUTION: The ferrule 11 is employed in which reinforcements 16,... for strengthening the wall 15 surrounding a recess 14 are formed at six places in the recess 14. The optical connector equipped with this ferrule 11 is also employed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a plastic optical fiber ferrule capable of terminating a plastic optical fiber used for optical transmission smoothly by a hot plate processing method, and a plastic optical fiber ferrule. The present invention relates to an optical connector.

[0002]

2. Description of the Related Art A plastic optical fiber (hereinafter referred to as an optical fiber) is obtained by coating a core material made of a fiber such as methacrylic resin with a fluorinated methacrylic resin. Used for optical transmission applications. When this kind of optical fiber is applied to optical communication or the like, it is required to treat the end face as smooth as possible. That is, if the end face is rough, the coupling loss with the light emitting / receiving element or the like increases. Therefore, it is necessary to smooth the end face in order to suppress this as much as possible.

[0003] The main methods of such finishing methods include, for example, a polishing treatment method for smoothing by polishing the end face, a free cutting treatment method for smoothing by cutting the end face, and a smoothing method for smoothing the end face. There is a hot plate treatment method for smoothing by pressing against a heated surface. Among them, the hot plate processing method has an excellent feature that an end face with higher accuracy than the free cut processing method can be processed in a shorter time than the polishing processing method.

FIG. 7 shows the hot plate processing method.
An example in which the process is performed using the conventional plastic optical fiber ferrule 1 (hereinafter referred to as ferrule 1) shown in FIGS. The ferrule 1 shown in the figure is a resin molded product having a substantially hollow cylindrical shape,
A concave portion 2 is formed in the distal end portion, into which the distal end portion (not shown) of the optical fiber melted when the optical fiber comes into contact with the heating surface, is formed to be recessed further than the distal end surface 3. I have. The recess 2 has an annular shape formed between an inner wall portion 5 having an inner diameter continuous with the guide hole 4 of the optical fiber and an outer wall portion 6 having an outer circumferential surface continuous with the outer circumferential surface of the ferrule 1. It is formed as a gap. The distal end surface 5a of the inner wall portion 5 is formed so as to be retracted more deeply than the distal end surface 3 of the outer wall portion 6 in order to guide the molten distal end portion of the optical fiber into the recess 2. .

According to the conventional ferrule 1, an optical fiber is inserted into the guide hole 4 so as to protrude from the distal end face 3 by a predetermined length (for example, about 0.3 mm) and fixed. As shown in FIG. 8, for example, the optical fiber F is held vertically, for example, for 5 to 10 seconds with respect to the smooth heating surface 7 of the hot plate (for example, a metal surface heated to about 160 ° C.). Press the ferrule 1 together. Then, the protruding portion is melted and deformed by the heat transfer from the heating surface 7 so as to fill the recess 2.
Since the optical fiber F at the time of the melt deformation is melted and fixed to the contact surfaces with the inner wall 5 and the recess 2 and the outer wall 6, the so-called pistoning phenomenon (the optical fiber F is completely fixed to the ferrule 1). The phenomenon that the optical fiber F protrudes outside from the front end face 3 of the ferrule 1 or retracts inside from the front end face 3 causes a problem such as a change in light quantity during light transmission or damage to the light receiving element. .) Can be prevented. The distal end face F1 of the optical fiber F thus formed is formed flat by being in close contact with the smooth heating surface 7. Thereafter, the heating of the heating surface 7 is stopped while maintaining the pressing state of FIG.
The distal end portion of the optical fiber F is cooled and solidified while maintaining the smooth distal end face F1, and the end face processing is completed.

[0006]

The conventional ferrule 1 described above has the following problems. That is, since the outer wall 6 forming the outer peripheral portion becomes thin because the concave portion 2 needs to be formed at the distal end portion, the molten portion of the plastic optical fiber F melts inside the concave portion 2. In this case, the resin-made thin outer wall portion 6 may be pressed from the inner peripheral side and plastically deformed so as to be pushed radially outward as shown in FIG. . If such plastic deformation occurs, the outer diameter of the ferrule 1 at the tip becomes an outer diameter d3 larger than the original outer diameter d1, so that the ferrule 1 after the termination is It cannot be inserted into the insertion port on the light receiving module (receptacle) side (not shown), and cannot be used.

The present invention has been made in view of the above circumstances, and has as its object to prevent the occurrence of a pistoning phenomenon and to provide a ferrule for a plastic optical fiber which is less likely to be deformed at the time of termination. It is another object of the present invention to provide an optical connector having the plastic optical fiber ferrule.

[0008]

According to the present invention, there is provided a ferrule for plastic optical fiber and an optical connector having the same.
The following means are employed in order to solve the above-mentioned problems. In other words, the plastic optical fiber ferrule according to claim 1 is characterized in that when the plastic optical fiber is inserted into the ferrule and pressed against a heating surface to terminate the plastic optical fiber, the melted distal end flows into the recess. In the plastic optical fiber ferrule formed on the surface, a plurality of reinforcing portions for reinforcing the peripheral wall of the concave portion are formed in the concave portion. Claim 1
According to the described plastic optical fiber ferrule,
When the plastic optical fiber ferrule holding the tip of the plastic optical fiber is pressed against the heating surface for termination processing, the tip of the plastic optical fiber melts due to the heat received from the heating surface and the concave portion is formed. It flows into the place and presses the surrounding wall from the inside, but this pressing force is reliably supported by the reinforcement. at the same time,
The melted portion that has flowed into the recess is firmly melt-fixed to a contact surface such as the inner wall surface of the recess.

According to a second aspect of the present invention, there is provided a ferrule for a plastic optical fiber according to the first aspect, wherein the recess extends an inner wall surface of a guide hole into which the plastic optical fiber is inserted in a direction toward a tip end surface of the ferrule. And an annular structure formed outside the inner wall portion having the inner wall surface. According to the plastic optical fiber ferrule of the second aspect, the same operation as that of the first aspect can be obtained.

According to a third aspect of the present invention, there is provided the ferrule for a plastic optical fiber according to the first or second aspect, wherein the plastic optical fiber is inserted when the reinforcing portion faces the front end face. The guide holes are arranged at equal angular intervals with respect to the center axis of the guide hole. According to the ferrule for a plastic optical fiber according to the third aspect, it is possible to prevent the deformation such that the outer diameter becomes large in various directions, and to fix the plastic optical fiber more effectively. be able to.

According to a fourth aspect of the present invention, there is provided a ferrule for a plastic optical fiber according to any one of the first to third aspects, wherein the reinforcing portion is formed at three or more locations. Features.
According to the ferrule for a plastic optical fiber according to the fourth aspect, the peripheral wall can be more uniformly reinforced at each point in the circumferential direction as compared with the case where one pair (two places) is provided in the radial direction. it can.

An optical connector according to a fifth aspect is the optical connector according to the first aspect.
4. The ferrule for plastic optical fibers according to any one of 4) is provided. According to the optical connector of the fifth aspect, it is possible to obtain the same operation as that of the first aspect.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a ferrule for a plastic optical fiber and an optical connector having the same according to the present invention will be described below with reference to the drawings. However, the present invention is not limited thereto. Of course.
FIG. 1 is a diagram showing an embodiment of an optical connector provided with a plastic optical fiber ferrule of the present invention, wherein FIG. 1A is a front view, and FIG. It is the side view seen. FIG. 2 is a view showing the same plastic optical fiber ferrule, and is an enlarged view of a portion C in FIG. 1A. FIG. 3 is a diagram showing the plastic optical fiber ferrule, and is a cross-sectional view taken along the line DD of FIG.

The optical connector 10 of the present embodiment shown in FIG.
Represents a resin molded part J attached to the tip of a plastic optical fiber (not shown) (not shown).
This is an ISC 5976 F07 type connector plug, which is connected to a connection port on the light receiving module (receptacle) (not shown) to connect with other optical fibers and optical components in the light receiving module and the optical fiber on the optical connector 10 side. Can be connected to each other. As shown in FIG. 1, the optical connector 10 has a pair (two) of plastic optical fiber ferrules (hereinafter referred to as ferrules 11, 11) with their tip portions protruding outside.
) Is fixed. These ferrules 11,
Since 11 is the same part, in the following description, only one ferrule 11 will be illustrated and the description will be continued.

As shown in FIGS. 2 and 3, the ferrule 1
1 is, for example, a reinforced PBT containing 10 to 30% glass fiber.
An outer shape made of (polybutyl terephthalate) resin and having an outer diameter dimension d1 that can be inserted into the insertion hole of the connection port;
It has a substantially hollow cylindrical shape with a guide hole 12 having an inner diameter d2 into which the tip of the optical fiber can be inserted. Further, when the distal end portion of the optical fiber is pressed against a heating surface for terminating (described later) in a state where the distal end portion of the optical fiber is inserted, a molten annular distal end portion flows into the distal end surface 13 of the ferrule 11. The recess 14 is formed so as to be recessed farther than the distal end face 13. In the recess 14, six reinforcing portions 16,... For reinforcing the peripheral wall portion 15 of the recess 14 from the inside are formed, and the arrangement of these reinforcing portions 16,. When the distal end surface 13 is viewed from the opposite side (that is, when viewed from the line of sight in FIG. 2), the distal end surfaces 13 are arranged at equal angular intervals (approximately 60 degrees) with respect to the guide hole 12 into which the optical fiber is inserted. ing.

The recess 14 includes an annular inner wall portion 18 having an inner diameter d2 continuous with the guide hole 12 and an annular peripheral wall portion 15 having an outer peripheral surface continuous with the outer peripheral surface of the ferrule 11. It is formed as an annular gap formed therebetween. The tip surface 18a of the inner wall portion 18 is
In order to guide the melted tip portion of the optical fiber into the recess 14, the tip surface of the peripheral wall portion 15 (that is, the ferrule 1) is used.
0 is formed so as to be retracted farther than the front end surface 13). Therefore, the tip shape of the ferrule 11 is such that the tip surface 18 a is recessed one step further from the tip surface 13.
And the bottom surface 14a of the recess 14 which is recessed one step further from the distal end surface 18a. In addition,
Reference numeral 13a indicates a chamfer.

Each of the reinforcing portions 16,... Has a substantially right-angled triangular plate shape, and one side sandwiching the right angle is the concave portion 1.
4 and the other side is joined to the inner peripheral surface 14b of the peripheral wall 15. Therefore, as shown in FIG. 3, the ferrule 1 with respect to the inner peripheral surface 14 b of the peripheral wall portion 15.
Both the pressing force from the inside and the pressing force from the outside against the outer peripheral surface 19b can be supported by the reinforcing portions 16,. .., The inner wall portion 18, and the peripheral wall portion 15.
Is formed integrally with the tip of the ferrule 11.

The ferrule 11 having the configuration described above,
An operation method from connection of an optical fiber to the optical connector 10 having the connector 11 to termination will be described below. FIG. 4 is a perspective view for explaining a method of connecting an optical fiber to the optical connector 10 and a terminating process, and FIG.
Is the first step, (b) is the next step,
(C) shows the next step. FIG.
FIG. 4 is a perspective view showing a continuation of the working method of the termination processing.
FIG. 6 is a cross-sectional view showing a continuation of the working method of the same termination processing, and is a cross-sectional view as seen from the same line of sight as FIG. In the present embodiment, a case where an optical cable 22 having a plastic optical fiber 22b having PMMA (abbreviation of polymethyl methacrylate) as a core and having a sheath of a fluorine-containing resin and connected to the optical connector 10 is described. Shall be.

As shown in FIG. 4, first, the stripper 2
By stripping the jacket 22a of the optical cable 22 by a predetermined length (for example, about 7 mm) by using 1, the optical fiber 22b is partially exposed. Then, the ferrule 11 is inserted into the insertion hole 10a formed in the optical connector 10 by a predetermined length (for example, about 0.3 mm).
After inserting the optical fiber 22b so as to protrude from the tip of the optical connector 11, the stopper mounting portion 10 of the optical connector 10 is inserted.
Press the stopper 25 into b. By this press-fitting, the jacket 22a in the optical connector 10 is sandwiched between the optical connector 10 and the stopper 25, so that the optical cable 2
2 is fixed to the optical connector 10 so that it cannot be pulled out.

The end face of the optical fiber 22b of the optical cable 22 attached to the optical connector 10 is processed by a hot plate heater 26 shown in FIG. That is, the hot plate heater 26 is provided with a heating surface 26a, which is heated to, for example, about 160 ° C., and the optical fiber 22b is perpendicularly moved to the optical connector 10 for, for example, 5 to 10 seconds. And press it. The pressure for pressing the optical connector 10 against the heating surface 26a is not particularly limited, but is generally about 1N to 20N. FIG.
Is the optical fiber 22b being pressed, and the protruding portion is melted and deformed so as to fill the recess 14 by receiving heat from the heating surface 26a, and the surface in close contact with the heating surface 26a is formed as a smooth surface.

At this time, the melted portion M of the optical fiber 22b flowing into the recess 14 presses the peripheral wall portion 15 from the inside, and the pressing force is applied to the reinforcing portions evenly arranged in the recess 14. 16,..., The outer diameter of the peripheral wall portion 15 is maintained so as not to be large. At the same time, the molten portion M that has flowed into the recess 14 is separated from the distal end surface 18 a of the inner wall portion 18 and the outer
b (see FIG. 3), the bottom surface 14 a of the recess 14, and the inner peripheral surface 14 b of the peripheral wall portion 15, but in the present embodiment, furthermore, in the present embodiment, six reinforcing portions 16,.・
Are provided, so that the surfaces of the reinforcing portions 16,... Function as a newly increased welding surface, so that it is possible to fix and weld more securely than before.

Thereafter, the heating of the heating surface 26a is stopped while maintaining the pressed state of FIG.
The tip portion 2b is cooled and solidified while maintaining the smooth tip surface 22c, and the end face processing is completed.

In the optical connector 10 of the present embodiment, reinforcing portions 16,... For reinforcing the peripheral wall portion 15 of the concave portion 14 from the inside are provided at six locations in each concave portion 14 of the ferrules 11, 11. Are arranged at equal angular intervals around the guide hole 12 into which the optical fiber 22b is inserted when the distal end face 13 is viewed from the opposite side. did. According to this configuration, even if the molten portion M of the optical fiber 22b flows into the recess 14 and presses the peripheral wall 15 of the concave 14 from the inside, the peripheral wall 15 is .. Can be prevented from being deformed so as to increase the outer diameter.

In addition, a recess 14 is formed in each of the tip surfaces 13 of the ferrules 11 and 11 so that the molten portion M can flow into the recess 14 and a simple flat surface without the recess 14 is formed. As compared with the case where the shape is used, the joining area with the molten portion M can be increased, and the joining area can be increased by newly installing the reinforcing portions 16,. This makes it possible to securely fix the optical fiber 22b to the ferrules 11 and 11, and it is possible to effectively prevent the occurrence of the pistoning phenomenon. Further, the plastic optical fiber ferrule of the present embodiment employs a configuration in which the reinforcing portions 16,... Are formed at six locations. According to this configuration, the peripheral wall portion 15 can be more uniformly reinforced at each point in the circumferential direction as compared with the case where one pair (two locations) is provided in the radial direction, so that the deformation at the time of termination is achieved. Can be made more difficult to occur.

The ferrules 11, 11 of the present embodiment
Is a separate component from the optical connector 10, but the present invention is not limited to this, and a configuration in which the ferrules 11 and 11 are integrally formed with the optical connector 10 may be employed. Further, the reinforcing portions 16,... Are formed at six places, but the present invention is not limited to this.
It is good also as what is provided more than a place. However, it can be said that it is more effective to provide three or more places than two places. Are preferably arranged at point-symmetric positions with respect to the center of the guide hole 12 as in the present embodiment. From this point, it is preferable that the number of the reinforcing portions 16 is an even number, more preferably, an even number of 4 or more. Further, the shape of the reinforcing portions 16,... Is a triangular plate shape, but is not limited thereto, and other shapes such as a square plate shape may be adopted. Further, in the present embodiment, the inner wall portion 18 having the inner wall surface that is continuous with the inner wall surface of the guide hole 12 is arranged, but a configuration in which such an inner wall portion 18 is omitted may be adopted. To demonstrate the effect of the present invention,
Approximately 15 glass fibers as the material for the ferrules 11 and 11
% Ferrule 1
The ferrules 11, 11 shown in the above embodiment were manufactured with the outer dimension d1 of 2.47 mm being attached to the optical connector 10. The optical fiber 22b was connected to the optical connector 10, pressed against the heating surface 26a with a force of 16N to perform a termination treatment, and the outer dimensions of the ferrules 11 and 11 were measured to be 2.47 mm. On the other hand, when the same termination was performed using the same optical connector as the optical connector 10 except that the reinforcing portions 16,... Were not disposed, the outer diameter of the ferrule was 2. Plastic deformation of 53mm, JIS C 5976 F
The ferrule external dimensions of the type 07 optical connector were out of the standard value (2.42 mm to 2.5 mm).

[0026]

The ferrule for a plastic optical fiber according to the first and second aspects of the present invention employs a structure in which a plurality of reinforcing portions for reinforcing the peripheral wall of the concave portion are formed in the concave portion. . According to this configuration, even if the melted optical fiber flows into the recess and presses the peripheral wall of the concave from the inside, the peripheral wall is reinforced in advance by the reinforcing portion. It is possible to prevent deformation such as thickening. Furthermore, a recess is formed in the tip surface of the plastic optical fiber ferrule, and the melted plastic optical fiber can flow into the recess, compared to a simple flat surface shape. Since the contact area of the plastic optical fiber with the molten portion can be greatly increased, the plastic optical fiber can be securely fixed to the plastic optical fiber ferrule, and the pistoning phenomenon can be effectively prevented. Has become.

Further, the plastic optical fiber ferrule according to claim 3 employs a configuration in which the reinforcing portions are arranged at equal angular intervals around the plastic optical fiber when the distal end face is viewed from the opposite side. . According to this configuration, it is possible to prevent deformation such that the outer diameter becomes large in various directions, and it is possible to more effectively fix the plastic optical fiber.

Further, the ferrule for a plastic optical fiber according to claim 4 employs a configuration in which the reinforcing portions are formed at three or more places. According to this configuration, 1 in the radial direction
As compared with the case of providing a pair (two places), the peripheral wall portion can be more uniformly reinforced at each point in the circumferential direction, so that deformation at the time of termination can be made harder to occur.

An optical connector according to a fifth aspect of the invention employs a configuration including the plastic optical fiber ferrule according to the first or second aspect. According to this configuration, it is possible to obtain the same effect as the first aspect.

[Brief description of the drawings]

FIG. 1 is a view showing an embodiment of an optical connector provided with a plastic optical fiber ferrule of the present invention,
(A) is a front view, (b) is a side view of (a) as viewed from line BB.

FIG. 2 is a view showing the same ferrule for plastic optical fiber, and is an enlarged view of a portion C in FIG. 1 (a).

3 is a view showing the plastic optical fiber ferrule, and is a cross-sectional view taken along the line DD of FIG. 2;

FIGS. 4A and 4B are perspective views illustrating a method of connecting an optical fiber to an optical connector having a plastic optical fiber ferrule and a terminating process, wherein FIG. 4A is the first step, and FIG. Shows the next step, and (c) shows the next step.

FIG. 5 is a perspective view showing a continuation of the working method of the termination processing.

FIG. 6 is a cross-sectional view showing a continuation of the working method of the same termination processing, and is a cross-sectional view as seen from the same line of sight as FIG. 3;

7A and 7B are diagrams showing an example of a conventional plastic optical fiber ferrule, wherein FIG. 7A is a front view, and FIG. 7B is a cross-sectional view of FIG.

FIG. 8 is a view for explaining a method of terminating a plastic optical fiber using the same plastic optical fiber ferrule, and is a cross-sectional view taken along the same line of sight as FIG. 7 (b).

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Optical connector 11 ... Ferrule (ferrule for plastic optical fibers) 12 ... Guide hole 13 ... Tip surface 14 ... Concavity 15 ... Peripheral wall part 16 ... Reinforcement part 18 ... Inner wall part 22b ... Plastic optical fiber 26a ... Heating surface M ... Merged tip part

Claims (5)

[Claims] When a plastic optical fiber is inserted into a plastic optical fiber with a distal end portion pressed against a heating surface to terminate the plastic optical fiber, the plastic optical fiber has a recess formed on the distal end surface as a recess into which the molten distal end portion flows. A ferrule for a plastic optical fiber, wherein a reinforcing portion for reinforcing a peripheral wall portion of the concave portion is formed at a plurality of locations in the fiber ferrule. 2. The method according to claim 1, wherein the recess has an annular structure formed on the outside of an inner wall having an inner wall extending from the inner wall of the guide hole into which the plastic optical fiber is inserted in the direction of the ferrule tip. The ferrule for plastic optical fibers according to claim 1, wherein 3. The reinforcing member is disposed at equal angular intervals with respect to a center axis of a guide hole through which the plastic optical fiber is inserted when the distal end face is viewed from the opposite side. Item 3. The ferrule for plastic optical fibers according to item 1 or 2. 4. The ferrule for a plastic optical fiber according to claim 1, wherein the reinforcing portion is formed at three or more places. 5. An optical connector comprising the ferrule for a plastic optical fiber according to claim 1. Description: