JP5199946B2 - Optical connector and assembly method thereof - Google Patents

Description

  The present invention relates to an optical connector attached to an optical fiber and an assembling method thereof.

  In connecting the optical fibers, a pair of ferrules having at least one optical fiber alignment hole and fixing the optical fiber in the optical fiber alignment hole, or a pair of plugs including the ferrule are provided. A technique of an optical connector that optically connects with a connecting member having refractive index matching is known (see, for example, Patent Document 1).

JP 2005-351998 A

By the way, in order to obtain sufficient connection characteristics of the optical connector, it is necessary that the transparent refractive index matching sheet (transparent body) and the end face of the optical fiber are sufficiently adhered.
However, if the pressing force (assembly pressing load) of the end face of the optical fiber to the transparent body is low when the optical fiber is inserted during assembly of the optical connector, a gap or separation occurs between the transparent body and the end face of the optical fiber, resulting in loss. There is a possibility that the connection characteristics are deteriorated by causing reflection.
Moreover, when the strength of the transparent body is weak, if the end face of the optical fiber is pressed too strongly against the transparent body, the optical fiber may protrude from the end face of the ferrule, and the transparent body may be damaged.

  Therefore, an object of the present invention is to provide an optical connector in which an end face of an optical fiber is appropriately pressed against a transparent body and good connection characteristics can be obtained without damage to the transparent body, and an assembling method thereof.

In the optical connector according to the present invention, which can solve the above-described problem, a transparent body is attached to the distal end surface of a ferrule through which a fiber insertion hole is formed so as to cover the fiber insertion hole, and is inserted into the fiber insertion hole. An optical connector in which an end face of the optical fiber is pressed against the transparent body,
After the end face of the optical fiber is pressed against the transparent body with a first pressing force, the end face of the optical fiber is held against the transparent body with a second pressing force that is weaker than the first pressing force. It has a pressing and fixing mechanism.

  In the optical connector according to the present invention, the pressing and fixing mechanism includes a fixing member that can grip the optical fiber, a support portion that supports the fixing member movably along the fiber insertion hole, and the fixing member. It is preferable to provide an elastic body that biases the optical fiber into the fiber insertion hole toward the rear side in the insertion direction.

  In the optical connector according to the present invention, the pressing and fixing mechanism includes a bending accommodating portion that can be accommodated in a state in which the optical fiber inserted through the fiber insertion hole is bent, and blocks a part of the bending accommodating portion. It is preferable that the bending reduction member that reduces the bending of the optical fiber is detachable.

In the optical connector assembling method of the present invention, an optical fiber in which a transparent body is attached to the front end surface of a ferrule through which a fiber insertion hole is formed so as to cover the fiber insertion hole, and is inserted into the fiber insertion hole. An end face of the optical connector pressed against the transparent body,
After the end face of the optical fiber is pressed against the transparent body with a first pressing force, the end face of the optical fiber is pressed against the transparent body with a second pressing force that is weaker than the first pressing force. It is characterized by fixing.

  In the method of assembling the optical connector according to the present invention, the first pressing force is applied to the optical fiber in a state where the abutting member is applied to the surface of the transparent body opposite to the surface to which the end surface of the optical fiber is pressed. It is preferable that the abutting member is separated from the transparent body after the end face is pressed against the transparent body and the end face of the optical fiber is pressed against the transparent body with the second pressing force.

  According to the optical connector and the assembling method thereof according to the present invention, by pressing the end face of the optical fiber against the transparent body with the first pressing force, the adhesion between the end face of the optical fiber and the transparent body can be improved. In addition, it is possible to suppress the loss or reflection of light due to the gap or separation between the transparent body and the end face of the optical fiber, and to obtain good connection characteristics. After the end face of the optical fiber is pressed against the transparent body with the first pressing force, the end face of the optical fiber is in close contact with the transparent body even if it is loosened to the second pressing force with a weaker pressing force. Maintained. Therefore, it is possible to prevent damage to the transparent body due to excessive pressing of the end face of the optical fiber against the transparent body while suppressing light loss and reflection, and to improve the connection reliability.

It is a disassembled perspective view which shows schematic structure of 1st Embodiment of the optical connector which concerns on this invention. It is a schematic longitudinal cross-sectional view of the connector plug assembly shown in FIG. It is an expanded sectional view in the ferrule tip part of the optical connector shown in FIG. It is explanatory drawing of the procedure of the assembly method which assembles | attaches an optical fiber to the optical connector shown in FIG. It is a graph which shows the relationship between the pressing force of the optical fiber end surface to a refractive index matching sheet, and loss. It is a disassembled perspective view which shows schematic structure of 2nd Embodiment of the optical connector which concerns on this invention. It is a schematic longitudinal cross-sectional view of the connector plug assembly shown in FIG. It is explanatory drawing of the procedure of the assembly method which assembles | attaches an optical fiber to the optical connector shown in FIG.

Hereinafter, an example of an embodiment of an optical connector and an assembling method thereof according to the present invention will be described with reference to the drawings.
(First embodiment)
First, the optical connector and its assembly method according to the first embodiment will be described.
1 is an exploded perspective view showing a schematic configuration of a first embodiment of an optical connector according to the present invention, FIG. 2 is a schematic longitudinal sectional view of the connector plug assembly shown in FIG. 1, and FIG. FIG. 4 is an explanatory diagram of the procedure of the assembly method for assembling the optical fiber to the optical connector shown in FIG. 1, and FIG. 5 is a graph showing the relationship between the pressing force of the optical fiber end face to the refractive index matching sheet and the connection loss. is there.

  The optical connector 1 according to the first embodiment is, for example, in the form of an SC connector. As shown in FIGS. 1 to 3, a connector plug assembly that contains a ferrule 3 and a base member 5 that holds the ferrule 3 , A connector knob 9 that is mounted on the plug housing 7 from the front, and a boot 11 that is mounted on the rear end of the plug housing 7.

  The ferrule 3 has an optical fiber insertion hole 15 through which the end of the optical fiber 14 is inserted on the central axis thereof. The optical fiber insertion hole 15 has a glass fiber 14a from which the coating has been removed on the tip side. Is a glass fiber insertion hole 16 having a diameter through which can be inserted.

A refractive index matching sheet 17 for matching the refractive indexes of the optical fibers at the time of connection with the optical connector of the connection partner is attached to the tip surface 3 a of the ferrule 3 so as to cover the glass fiber insertion hole 16. Yes. This refractive index matching sheet 17 is a transparent body having a refractive index equivalent to that of the core of the glass fiber 14 a, is a sheet having a thickness of 5 to 30 μm, and is on the surface in contact with the tip surface 3 a of the ferrule 3. The adhesive for applying the adhesive material to the ferrule 3 is given. The outer surface of the refractive index matching sheet 17 is not sticky, and dust or the like is difficult to adhere.
A groove portion (not shown) communicating with the glass fiber insertion hole 16 is formed on the tip surface 3a of the ferrule 3 at a position facing each other. Further, in order to escape air trapped between the refractive index matching sheet 17 and the tip surface 3a of the ferrule 3, a minute air hole may be provided in the refractive index matching sheet 17 or the tip surface 3a.

  The base member 5 has an insertion hole 5a through which the optical fiber 14 can be inserted, and the optical fiber 14 is inserted from the rear end side of the base member 5 into the insertion hole 5a.

  A cylindrical plug holder (supporting portion) 21 is attached to the rear end of the base member 5. The plug holder 21 has an engaging portion 22 that extends toward the rear end, and a stopper that protrudes toward the inner peripheral side of the base member 5 at the rear end portion of the engaging portion 22. 23 is formed.

  A gripping member (fixing member) 25 for gripping the optical fiber 14 is provided at the rear end of the base member 5 so as to be movable along the insertion direction of the optical fiber 14. Between the rear end surface 5b of the base member 5 and the gripping member 25, a compression spring (elastic body) 26 that biases the gripping member 25 rearward is provided. The gripping member 25 urged rearward by the compression spring 26 is restricted from moving further rearward by contacting the stopper 23.

In the optical connector 1, the optical fiber 14 is held by the holding member 25 in a state of being biased forward in the insertion direction. Thereby, the front end surface of the glass fiber 14a of the optical fiber 14 is pressed and brought into close contact with the refractive index matching sheet 17 provided with adhesiveness on the contact surface side with the front end surface 3a of the ferrule 3.
The glass fiber 14a slightly protrudes from the distal end surface 3a of the ferrule 3 and is pushed back by the ferrule of the other optical connector when connected.

  In this first embodiment, the gripping member 25, the plug holder 21, and the compression spring 26 are weaker than the first pressing force after the end surface of the optical fiber 14 is pressed against the refractive index matching sheet 17 with the first pressing force. The pressing and fixing mechanism 10 is configured to hold the end face of the optical fiber 14 in a state of being pressed against the refractive index matching sheet with a pressing force of 2.

Next, an optical connector assembling method according to the first embodiment will be described.
The optical connector 1 is assembled in the procedure shown in FIGS.
First, as shown in FIG. 4A, the coating at the end of the optical fiber 14 is removed to expose the glass fiber 14a for a predetermined length.

  Next, as shown in FIG. 4B, the optical fiber 14 is passed through the gripping member 25 and further inserted into the insertion hole 5a of the base member 5, the optical fiber insertion hole 15 of the ferrule 3, and the glass fiber insertion hole 16. The end of the glass fiber 14 a is brought into contact with the refractive index matching sheet 17.

  At this time, the air in the optical fiber insertion hole 15 and the glass fiber insertion hole 16 of the ferrule 3 is released to the outside from the groove formed in the distal end surface 3a of the ferrule 3, so that the glass fiber 14a is connected to the refractive index matching sheet 17 and The end face is in close contact with the refractive index matching sheet 17 without air remaining.

  However, although the tip of the glass fiber 14a is slightly pressed against the refractive index matching sheet 17, the pressing force is weak (state A in FIG. 5). In this state, the refractive index matching sheet 17 A good contact state with the optical connector 1 is not ensured, and light loss and reflection when the optical connectors 1 are connected to each other are increased.

  Next, the optical fiber 14 is held by the gripping member 25, and the gripping member 25 is displaced forward in the insertion direction against the urging force of the compression spring 26, as shown in FIG. Push in. At this time, if the compression spring 26 is sufficiently compressed, no further pressing is performed. If it does in this way, the pressing force of the glass fiber 14a with respect to the refractive index matching sheet 17 will rise to the force (1st pressing force) determined by the spring force of the compression spring 26 (state of the code | symbol B in FIG. 5). Thereby, the front-end | tip of the glass fiber 14a is fully pressed with respect to the refractive index matching sheet | seat 17, In this state, the favorable contact | adherence state with the refractive index matching sheet | seat 17 is ensured, and when the optical connectors 1 are connected The loss or reflection of light is suppressed.

However, this state is a state in which the tip surface of the glass fiber 14a is strongly pressed against the refractive index matching sheet 17, so that an excessive force continues to be applied to the refractive index matching sheet 17 and the refractive index matching sheet 17 is damaged. There is a possibility that.
Therefore, once the optical fiber 14 is pushed in with a strong force (first pressing force), the pushing of the optical fiber 14 is released. As a result, as shown in FIG. 4D, the optical fiber 14 is displaced rearward until the gripping member 25 biased rearward by the compression spring 26 abuts against the stopper 23 and the movement is restricted. .

As a result, the pressing force of the glass fiber 14a against the refractive index matching sheet 17 is reduced to a small pressing force (second pressing force) (state C in FIG. 5). Thereby, damage to the refractive index matching sheet 17 due to the pressing of the glass fiber 14a against the refractive index matching sheet 17 is avoided.
In addition, in this state, the glass fiber 14 a is once pressed against the refractive index matching sheet 17 with a large pressing force, so that the tip of the glass fiber 14 a is kept in a good contact state with the refractive index matching sheet 17. Thereby, the loss and reflection of light when the optical connectors 1 are connected to each other are greatly suppressed, and good connection characteristics can be obtained.

  Further, the first pressing force is applied with a contact member (such as a contact plate) applied to a surface (left end surface in FIG. 4) opposite to the surface to which the tip of the glass fiber 14a is pressed in the refractive index matching sheet 17. When the end face of the glass fiber 14a is pressed against the refractive index matching sheet 17 and the end face of the glass fiber 14a is pressed against the refractive index matching sheet 17 with the second pressing force, the pressing force of the glass fiber 14a is more reliably applied. It is easy to obtain good connection characteristics. Further, since the deformation of the refractive index matching sheet 17 can be suppressed even if a pressing force is applied, damage to the refractive index matching sheet 17 can be prevented. After the second pressing force is applied, the contact member may be separated from the refractive index matching sheet 17.

The pressing force for pressing the glass fiber 14a against the refractive index matching sheet 17 is 25,000 gf / mm ² or more and 40,000 gf / mm ² or less (250 N) as a large pressing force (first pressing force) that is temporarily pressed at the time of assembly. / Mm ² or more and 400 N / mm ² or less), and the weak pressing force (second pressing force) in the subsequent use state is 10,000 gf / mm ² or less (100 N / mm ² or less). Is preferable.

  As described above, according to the optical connector and the assembly method thereof according to the first embodiment, the end face of the glass fiber 14a of the optical fiber 14 is attached to the refractive index matching sheet 17 by the first pressing force which is a large pressing force. By pressing, the adhesion between the end face of the glass fiber 14a and the refractive index matching sheet 17 can be enhanced. Thereby, the loss and reflection of the light by the space | gap and peeling between the refractive index matching sheet 17 and the glass fiber 14a can be suppressed, and a favorable connection characteristic can be obtained.

Further, after the end face of the glass fiber 14a is pressed against the refractive index matching sheet 17 with a large pressing force, the end face of the glass fiber 14a is pressed against the refractive index matching sheet 17 because the second pressing force, which is a weak pressing force, is loosened. It is possible to prevent the refractive index matching sheet 17 from being damaged due to the excess, and to improve the connection reliability.
Further, according to the optical connector 1, by adjusting the elastic force of the compression spring 26, the pressing force of the end face of the glass fiber 14a to the refractive index matching sheet 17 can be set to an appropriate load very easily. it can.

(Second Embodiment)
Next, an optical connector and its assembly method according to the second embodiment will be described. In addition, the same structure and the same component as 1st Embodiment attach | subject the same code | symbol, and abbreviate | omit description.
6 is an exploded perspective view showing a schematic configuration of a second embodiment of the optical connector according to the present invention, FIG. 7 is a schematic longitudinal sectional view of the connector plug assembly shown in FIG. 6, and FIG. 8 is a diagram of the light shown in FIG. It is explanatory drawing of the procedure of the assembly method which attaches an optical fiber to a connector.

  As shown in FIGS. 6 and 7, in the optical connector 1 </ b> A of the second embodiment, a wedge insertion hole 31 is formed on the side of the base member 5. Further, the base member 5 is formed with a bending housing portion 32 that communicates with the wedge insertion hole 31, and a part of the insertion hole 5a is expanded laterally.

  In the wedge insertion hole 31, a plate portion (a bending reduction member) 33 of an insertion plate 34 having a pair of plate portions 33 formed at a distance from each other can be attached / detached (inserted / removed). Then, by inserting the plate portion 33 of the insertion plate 34 into the wedge insertion hole 31, each plate portion 33 is arranged in parallel to the insertion hole 5 a in the bending housing portion 32.

  In the optical connector 1 </ b> A, the optical fiber 14 passed through the insertion hole 5 a is in a state of being gently bent in the bending housing portion 32. Thereby, the front-end | tip part of the glass fiber 14a is pressed to the front-end | tip direction by the restoring force of the bent optical fiber 14, and is always pressed against the refractive index matching sheet 17. FIG.

  In the second embodiment, the bending housing portion 32 and the plate portion 33 press the end face of the optical fiber 14 against the refractive index matching sheet 17 with the first pressing force, and then the second pressing force is weaker than the first pressing force. The pressure fixing mechanism 10A is configured to hold the end face of the optical fiber 14 in a state of being pressed against the refractive index matching sheet by force.

Next, an optical connector assembling method according to the second embodiment will be described.
The optical connector 1A is assembled in the procedure shown in FIGS.
First, as shown in FIG. 8A, the coating on the end of the optical fiber 14 is removed to expose the glass fiber 14a for a predetermined length. Further, the plate portion 33 of the insertion plate 34 is inserted into the wedge insertion hole 31 so as to protrude into the bending housing portion 32.

  Next, as shown in FIG. 8B, the optical fiber 14 is inserted into the insertion hole 5 a of the base member 5, and the end of the glass fiber 14 a is brought into contact with the refractive index matching sheet 17.

  At this time, the air in the optical fiber insertion hole 15 and the glass fiber insertion hole 16 of the ferrule 3 is released to the outside from the groove formed in the distal end surface 3a of the ferrule 3, so that the glass fiber 14a is connected to the refractive index matching sheet 17 and The end face is in close contact with the refractive index matching sheet 17 without air remaining.

  However, the tip of the glass fiber 14a is slightly pressed against the refractive index matching sheet 17, but the pressing force is weak (state A in FIG. 5). In this state, the refractive index matching sheet 17 is not secured, and the loss and reflection of light when optical connectors are connected to each other are increased.

  Next, the optical fiber 14 is pushed in from this state, and the optical fiber 14 is fixed on the rear end side of the base member 5. If it does in this way, as shown in FIG.8 (c), a part of optical fiber 14 will enter into the bending | flexion accommodating part 32, bending | flexing from the clearance gap between the board parts 33 of the insertion board 34, and the optical fiber 14 is inserted. In addition, a buckling force is generated by bending and bending small, and the pressing force of the glass fiber 14a against the refractive index matching sheet 17 increases to a large pressing force (first pressing force) due to the buckling force (FIG. 5). (State of middle code B).

  In the state of FIG. 8C, the tip of the glass fiber 14a is sufficiently pressed against the refractive index matching sheet 17, and in this state, a good contact state with the refractive index matching sheet 17 is ensured, and the optical connector. Loss and reflection of light when connecting each other is suppressed.

After the optical fiber 14 is pushed in, the plate portion 33 of the insertion plate 34 is pulled out from the wedge insertion hole 31 of the base member 5. In this way, as shown in FIG. 8D, the plate portion 33 of the insertion plate 34 is removed from the bending housing portion 32, and one of the optical fibers 14 that has entered the gap between the plate portions 33 of the insertion plate 34. The bent state of the part is loosened.
When the bent state is loosened, the pressing force of the glass fiber 14a against the refractive index matching sheet 17 is reduced to a small pressing force (second pressing force) (state C in FIG. 5). Thereby, damage to the refractive index matching sheet 17 due to excessive pressing of the glass fiber 14a to the refractive index matching sheet 17 is prevented.

  Further, when the glass fiber 14 a is once pressed against the refractive index matching sheet 17 with a large pressing force, the tip of the glass fiber 14 a is maintained in a good contact state with the refractive index matching sheet 17. Thereby, the loss and reflection of light when optical connectors are connected to each other are greatly suppressed, and good connection characteristics can be obtained.

  Also in the second embodiment, as in the first embodiment, the contact member is applied to the refractive index matching sheet 17 when the first pressing force and the second pressing force are applied, and then the refractive index matching sheet 17 is applied. By separating from the distance, the pressing force of the glass fiber 14a can be applied to the refractive index matching sheet 17 more reliably, and good connection characteristics can be easily obtained.

  As described above, according to the optical connector and the assembling method thereof according to the second embodiment, as in the first embodiment, the glass fiber 14a of the optical fiber 14 has the first pressing force that is a large pressing force. By pressing the end face against the refractive index matching sheet 17, the adhesion between the end face of the glass fiber 14 a and the refractive index matching sheet 17 can be improved, and thereby the gap between the refractive index matching sheet 17 and the glass fiber 14 a Light loss and reflection due to peeling can be suppressed, and good connection characteristics can be obtained.

  Further, after the end face of the glass fiber 14a is pressed against the refractive index matching sheet 17 with a large pressing force, the end face of the glass fiber 14a is pressed against the refractive index matching sheet 17 because the second pressing force, which is a weak pressing force, is loosened. It is possible to prevent the refractive index matching sheet 17 from being damaged due to the excess, and to improve the connection reliability.

  Further, according to the optical connector 1A, the end face of the glass fiber 14a is pressed against the refractive index matching sheet 17 by adjusting the distance between the plate portions 33 of the insertion plate 34 to adjust the bending amount of the optical fiber 14. The force can be set to an appropriate load.

  In the first and second embodiments, the refractive index matching sheet is used as the transparent body. However, the transparent body used in the present invention does not necessarily have the same refractive index as the core of the optical fiber. Any material may be used as long as it has transparency and refractive index that can suppress loss and reflection of light.

DESCRIPTION OF SYMBOLS 1,1A: Optical connector, 3: Ferrule, 3a: Tip surface 10, 10A: Press fixing mechanism, 14: Optical fiber, 14a: Glass fiber, 15: Optical fiber insertion hole (fiber insertion hole), 16: Glass fiber Insertion hole (fiber insertion hole), 17: Refractive index matching sheet (transparent body), 21: Plug holder (support part), 25: Holding member (fixing member), 26: Compression spring (elastic body), 32: Deflection accommodation Part, 33: plate part (deflection reduction member)

Claims (3)

An optical connector in which a transparent body is attached to the front end surface of a ferrule through which a fiber insertion hole is formed so as to cover the fiber insertion hole, and an end surface of the optical fiber inserted into the fiber insertion hole is pressed against the transparent body. Because
A pressing and holding mechanism that holds the optical fiber inserted into the fiber insertion hole in a bent state and holds the optical fiber in a state of pressing the end face of the optical fiber against the transparent body;
A bending reduction member that is detachably provided with respect to the bending housing portion, and that blocks a portion of the bending housing portion to reduce the bending of the optical fiber.
The pressing and fixing mechanism is configured such that the bending reduction member is bent from the state in which the end face of the optical fiber is pressed against the transparent body with a first pressing force in a state where the bending reduction member is attached to the bending housing portion. It is characterized in that a second pressing force that is weaker than the first pressing force can be applied to the end face of the optical fiber by changing the length in the fiber axial direction of the bending accommodating portion by being removed from the accommodating portion. Optical connector. An optical connector in which a transparent body is attached to the front end surface of a ferrule through which a fiber insertion hole is formed so as to cover the fiber insertion hole, and an end surface of the optical fiber inserted into the fiber insertion hole is pressed against the transparent body. The assembly method of
The optical connector is
A pressing and holding mechanism that holds the optical fiber inserted into the fiber insertion hole in a bent state and holds the optical fiber in a state of pressing the end face of the optical fiber against the transparent body;
A bending reduction member that is detachably provided with respect to the bending housing portion, and that blocks a portion of the bending housing portion to reduce the bending of the optical fiber.
The bending reduction member is attached to the bending accommodating portion, and the end face of the optical fiber is pressed against the transparent body with a first pressing force .
The bending reduction member is removed from the bending housing portion, the length of the bending housing portion in the fiber axial direction is changed, and the end face of the optical fiber is moved by the second pressing force that is weaker than the first pressing force. An optical connector assembling method, wherein the optical fiber is fixed by being pressed against a transparent body. An optical connector assembling method according to claim 2 ,
In a state where the abutting member is applied to the surface of the transparent body opposite to the surface to which the end face of the optical fiber is pressed, the end face of the optical fiber is pressed against the transparent body with the first pressing force. After pressing the end face of the optical fiber against the transparent body with the pressing force of
An optical connector assembling method, wherein the contact member is separated from the transparent body.

Images