JP2001116952A - Ferrule for optical connector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ferrule for an optical connector such that the ferrule can automatically and surely reduce an output from an optical output end when the connector is removed from an optical transmitter device and that the ferrule with a mechanism capable of the reducing function can maintain the same shape and dimension as those of a conventional standard ferrule. SOLUTION: The ferrule is provided with a cylindrical body-side ferrule part 21 holding an optical fiber 25 in a through-hole in the center, a cylindrical ferrule sleeve 22 fixed on the body-side ferrule part 21, and a cylindrical tip end-side ferrule part 24 which holds the optical fiber 25 in the through-hole in the center, and which is inserted into the ferrule sleeve 22 so as to be freely slidable in the center axial direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ferrule for an optical connector having improved safety when connecting or disconnecting an optical fiber in, for example, an optical transmission device or an optical fiber transmission line.

In general, since an optical signal for communication uses light in a wavelength band that is invisible, there is a danger that an operator may be exposed to the eyes or skin when attaching or detaching or connecting an optical connector. Therefore, safety measures are needed.

Hitherto, as a safety measure, means for shutting down or reducing the optical output when an optical connector is detached from a mounted portion has been considered, and the means are roughly classified into two systems.

That is, (1) a circuit for detecting the reflection of light and cutting off the light output (if necessary, see Japanese Patent Application Laid-Open No. 3-276778, and
No. 34529). (2) An optical connector having a light blocking structure (refer to Japanese Patent Application Laid-Open No. 5-281439 if necessary). Such means are known.

The circuit (1) is a circuit for detecting the reflected light generated when the optical connector is detached and cutting off the light output from the laser light source.

FIG. 9 is a main block diagram showing an optical output cutoff circuit. In the figure, reference numeral 1 denotes an optical output circuit, and 2 denotes an optical system using a directional coupler or a coupler for forming a reflected light route. 3, a photodetector, 4 a light blocking circuit (control circuit),
5A and 5B show optical connectors, respectively.

In the optical output cutoff circuit shown in the figure, reflected light generated when the optical connector 5A comes off the opposing optical connector 5B is detected by the photodetector 3 via the optical system 2, and the light cutoff circuit is provided. The light output circuit 1 is controlled by the cutoff signal output from the light output circuit 4 to directly cut off the light output.

In such an optical output cutoff circuit, a circuit shown in the figure is required for each line of the optical transmission device. There is a drawback that the system becomes large-scale, and the light propagation is not automatically restored even if the optical connector is fitted after the light output is cut off, which is too many problems for practical use. .

In the above (2), a light blocking mechanism is attached to the optical connector so that the propagation / blocking of light can be automatically controlled when the optical connector is attached / detached.

FIG. 10 is a side view showing a main part of a conventional optical fiber connector having a light blocking structure.
1 denotes an optical connector / ferrule, 12 denotes a light shielding plate, 13 denotes a fixture, and 14 denotes a coil spring.

In order to fit the optical fiber connector to an object, a part of the light shielding plate 12 located on the opposite side of the coil spring 14 with the fixture 13 therebetween is pressed, so that the optical connector ferrule 1 is pressed. When the optical fiber connector is inserted by removing the light shielding plate 12 from the light output end, and when the optical fiber connector is removed from the object, the light shielding plate 12 is automatically operated by the action of the coil spring 14.・
The light output end of the ferrule 1 will be shielded.

An optical fiber having such a light blocking structure
To realize a connector, an optical connector ferrule 1
It is necessary to attach the light shielding mechanism to the housing in the above, so it differs greatly from the structure of the standard optical fiber connector, such as the specialty of the structure and the consistency with the mating object Therefore, it is difficult to apply the optical transmission device to an existing optical transmission device as it is.

[0013]

According to the present invention, there is provided a mechanism for automatically and reliably reducing the optical output from the optical output terminal when the optical connector is disconnected from the optical transmission device, and furthermore, providing a mechanism for enabling the reduction. The ferrule can maintain the same shape and dimensions as a conventional standard ferrule.

[0014]

According to the present invention, a ferrule having a standard shape and dimensions has a structure in which a tip portion is separated from a main body and is movable in a mounting / removing direction. And

From the above description, in the ferrule for an optical connector according to the present invention, (1) an optical fiber (for example, an optical fiber
5: A cylindrical body-side ferrule portion (for example, body-side ferrule portion 23) holding a body-side ferrule portion (see FIGS. 1 and 2; the same applies hereinafter), and a cylindrical ferrule sleeve fixed to the body-side ferrule portion ( For example, a ferrule sleeve 22) and a cylindrical distal ferrule portion which is formed in a cylindrical shape by holding an optical fiber in a central through-hole and which is inserted into the ferrule sleeve and is slidable in the central axis direction. (E.g., a tip side ferrule portion 24), or

(2) In the above (1), the opposite connection end faces of the main body side ferrule portion and the front end side ferrule portion are PC polished surfaces (for example, see FIG. 3 (B)).
Characterized in that, or

(3) In the above (1), the oblique PC polished surface that bends the optical path in a state where the opposing connection end surfaces of the main body side ferrule portion and the front end side ferrule portion are separated from each other (for example, FIG. C), (D)), or

(4) In the above (1), a coil spring (for example, a coil spring 28: see FIG. 4) is interposed between the tip of the ferrule sleeve and the tip side ferrule to insert the main body side ferrule. Or biasing the distal ferrule portion away from, or

(5) In the above (1), a coil spring (for example, see FIG. 5) is inserted into and separated from the main body side ferrule portion and the front end side ferrule portion in the ferrule sleeve. Characterized in that:

(6) In the above (1), a slit (for example, a slit 22B: see FIG. 8) is formed to allow the diameter of the ferrule sleeve to be increased when the ferrule portion is fitted into the distal end of the ferrule sleeve. Is characterized by being done, or

(7) In the above (1), a leaf spring (for example, leaf spring 29: see FIGS. 6 and 7) is fixed to the tip of the ferrule sleeve, and the leaf spring is attached to the tip side ferrule portion. The frusto-conical portion (for example, frusto-conical portion 24C: see FIG. 6 and FIG. 7) is biased so as to separate the distal-side ferrule portion from the main-body-side ferrule portion. Or

(8) In the above (7), a rail groove (for example, a rail groove 24L) for receiving a part of the leaf spring is formed in the frustoconical portion of the tip side ferrule portion with which the leaf spring contacts. It is characterized by becoming.

By employing the above means, when the optical connector is removed from the optical transmission device, the optical output from the tip of the optical connector is automatically reduced, and the function of preventing the danger can be sufficiently achieved. The shape and dimensions can be exactly the same as standard ferrules that have been widely used in the past. Therefore, the ferrules according to the present invention can be substituted for ferrules in conventional optical connectors and used without any change. be able to.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 and 2 are a perspective view and a cutaway side view, respectively, showing a main part of an optical connector for explaining a first embodiment of the present invention. 1B shows a state at the time of removal, FIG. 1B shows a state in which a part of FIG. 1A is seen through, and FIG. 2A shows a state in which the ferrule for an optical connector is an optical transmission device via an adapter for an optical connector. FIG. 2B shows a state in which the ferrule for optical connector is being removed from the adapter for optical connector of the ferrule for opposed optical connector, respectively.

In the drawing, 21 is a ferrule for an optical connector, 22 is a sleeve for a ferrule, 22A is an inwardly projecting edge, 23 is a ferrule part on the main body side, 24 is a ferrule part on the tip side, 24A is a large diameter part, and 24B is a ferrule part. A small diameter portion, 25 is an optical fiber, 26 is an adapter for an optical connector, and 27 is a ferrule for an opposing optical connector.

Here, the material forming the main body side ferrule portion 23 and the tip side ferrule portion 24 is preferably a material having high strength and good machinability, such as zirconia ceramic, and a ferrule sleeve. As a material for forming 22, a metal or a plastic having an elastic force is preferable.

As is clear from the drawings, the ferrule 21 for an optical connector is divided into a main body side ferrule portion 23 and a tip side ferrule portion 24, and a ferrule sleeve 22 is fitted on the main body side ferrule portion 23. ing.

A distal ferrule portion 24 is slidably inserted in the ferrule sleeve 22, and a small diameter portion 24B is provided in the middle of the distal ferrule portion 24, and a large diameter portion is provided at the most distal end. A portion 24A is formed, and the small-diameter portion 24B is formed.
The inwardly protruding edge 22A of the ferrule sleeve 22 is located at the front end to prevent the distal ferrule portion 24 from coming out of the ferrule sleeve 22.
The diameter of A is substantially equal to the outer diameter of the ferrule sleeve 22.

The optical connector adapter 26 into which the optical connector ferrule 21 is inserted is fixed to the opposing optical connector ferrule 27.

As shown in FIG. 2A, when the optical connector ferrule 21 is fitted into the optical connector adapter 26 and pushed in, the distal ferrule portion 24 comes into contact with the distal end of the opposing optical connector ferrule 27. When the pusher is further pushed in, the distal ferrule portion 24 slides relatively inside the ferrule sleeve 22 toward the main body ferrule portion 23, and the distal ferrule portion 24
And the main body side ferrule portion 23 abut against the optical fiber 2
5 is terminated.

As shown in FIG. 2B, when the optical connector ferrule 21 is removed from the optical connector adapter 26, the distal ferrule portion 24 is connected to the outer periphery of the large-diameter portion 24A and the optical connector ferrule 21. The ferrule is stopped by the contact friction with the inner surface of the adapter 26, so that the ferrule sleeve 22 is relatively slid in the ferrule sleeve 22 so as to be separated from the main body side ferrule portion 23. At the stage where the inwardly projecting edge 22 </ b> A of the sleeve 22 abuts the step of the distal ferrule portion 24, the distal ferrule portion 24 is removed in a state integrated with the ferrule sleeve 22.

As described above, the optical connector adapter 2
In the ferrule 21 for an optical connector removed from 6, the ferrule portion 23 on the main body side and the ferrule portion 24 on the distal end side are separated in the ferrule sleeve 22, that is, the connection of the optical fiber 25 is released. As a result, the optical connection loss there increases, and the light output from the distal ferrule portion 24 is significantly reduced, so that the laser light therefrom has no adverse effect.

FIG. 3 is a cutaway side view showing a main part of an optical connector ferrule for explaining various embodiments.
(A) is the first embodiment described with reference to FIGS.
(B) is Embodiment 2, (C) and (D)
Represents the third embodiment, and the same symbols as those used in FIGS. 1 and 2 represent the same parts or have the same meanings.

In the first embodiment shown in FIG. 3A, the connection abutment surface between the main body side ferrule portion 23 and the tip side ferrule portion 24 in the optical connector ferrule 21 is polished flat.

In the embodiment 2 shown in FIG. 3 (B), the contact abutment surface between the main body side ferrule portion 23 and the tip side ferrule portion 24 in the optical connector ferrule 21 is physically polished, ie, PC (physical con
tact) has been polished.

In the second embodiment, when the main body side ferrule portion 23 and the front end side ferrule portion 24 are connected and abutted, the optical fiber 25 is also connected to the PC, and stable connection with reduced light loss is possible.

In the third embodiment shown in FIGS. 3 (C) and 3 (D), the connection abutment surface between the main body side ferrule portion 23 and the front end side ferrule portion 24 in the optical connector ferrule 21 is obliquely PC-polished. I have.

In the third embodiment, as shown in FIG. 3C, when the main ferrule portion 23 and the distal ferrule portion 24 are connected to each other, the optical fiber 25 is also connected to the PC.
Although the connection enables stable connection with reduced light loss, as shown in FIG. 3D, when the connection between the main body side ferrule portion 23 and the front end side ferrule portion 24 is separated, Since the light is refracted on the polished surface of the PC and the optical path is bent in the gap created by the separation, the optical connection loss is further increased, and the tip side ferrule portion 24
The light output from the tip is greatly reduced.

FIG. 4 is a sectional side view showing a main part of an optical connector ferrule for explaining a fourth embodiment of the present invention. FIG. 4A shows a main body side ferrule portion 23 and a front end side ferrule portion 24. (B) shows a state in which the main body side ferrule portion 23 and the front end side ferrule portion 24 are connected and abutted, respectively, and the same symbols as those used in FIGS. Or have the same meaning.

In the fourth embodiment, the small-diameter portion 24B is located between the inward protruding edge 22A of the ferrule sleeve 22 and the large-diameter portion 24A of the distal ferrule portion 24. Is wound and a coil spring 28 is interposed therebetween.

Therefore, the tip side ferrule portion 24 is always urged in the direction away from the main body side ferrule portion 23, and the ferrule 21 for the optical connector is inserted into the adapter 26 for the optical connector so that the ferrule for the opposite optical connector is inserted. 27, it is necessary to insert it in a state of being compressed and contracted against the resilience of the coil spring 28, but at the time of removal, the distal ferrule portion 24 Main body side ferrule part 2 depending on action
3, the light output from the tip side ferrule portion 24 is reliably reduced, and safety is improved.

FIG. 5 is a cutaway side view showing a main part of an optical connector ferrule for explaining Embodiment 5 of the present invention. FIG. 5A shows a main body side ferrule portion 23 and a front end side ferrule portion 24. (B) shows a state in which the main body side ferrule portion 23 and the front end side ferrule portion 24 are connected and abutted, respectively, and the same symbols as those used in FIGS. Or have the same meaning.

In the fifth embodiment, the coil spring 28 used in the fourth embodiment is replaced with the main body side ferrule portion 2.
3 and the front ferrule portion 24, the receiving steps 23S and 24S of the coil spring 28 are formed at the front end of the main body ferrule portion 23 and the rear end of the front ferrule portion 24. ing.

Ferrule 2 for Optical Connector of Embodiment 5
The operation at the time of inserting / removing 1 into / from the optical connector adapter is exactly the same as that of the fourth embodiment, and when it is inserted, as shown in FIG. Since 28 is housed in the receiving steps 23S and 24S, there is no problem in the optical connection between the main body side ferrule portion 23 and the distal side ferrule portion 24.

FIG. 6 is a cutaway view of a main part of an optical connector ferrule for explaining a sixth embodiment of the present invention. FIG. 6A shows a main body side ferrule portion 23 and a front end side ferrule portion 24. (B) shows a state where the main body side ferrule portion 23 and the front end side ferrule portion 24 are connected and abutted, respectively, and (C) and (D) show a front end of the ferrule main body for an optical connector. Is an enlarged cross-sectional view of a main part, and (E) is a front view of the main part also cut. The same symbols as those used in FIGS. 1 to 5 represent the same parts or have the same meaning.

As is apparent from the figure, in the sixth embodiment, a truncated conical portion 24C having an exponentially curved surface when viewed in a side cross section is formed in a part of the tip side ferrule portion 24. A leaf spring 29 formed at the tip of the ferrule sleeve 22 is in contact with the curved surface. still,
The side circumference of the truncated conical portion 24C need not be an exponentially curved surface, but may be a normal inclined surface.

The leaf spring 29 is provided on the ferrule sleeve 22.
In this state, the resilient force for expanding in the direction of the center axis is always applied to the curved surface of the frusto-conical portion 24C. As in the case of Embodiment 4 or Embodiment 5, it is in a state where it is constantly urged in a direction away from the main body side ferrule portion 23.

Therefore, when the ferrule 21 for an optical connector is inserted into the adapter 26 for an optical connector and is connected to the ferrule 27 for the opposing optical connector, the ferrule 21 for the optical connector is further connected at the stage when the connection is performed. The distal ferrule portion 24 slides within the ferrule sleeve 22 while applying a pressing force to the leaf spring 29 on the curved surface of the truncated conical portion 24C by being pushed in, so that the distal ferrule portion 24 engages with the main body ferrule portion 23. Is completed, and when removed, the distal ferrule portion 24 is automatically separated from the main body ferrule portion 23 by the action of the curved surface of the truncated conical portion 24C and the leaf spring 29. Needless to say.

FIG. 7 is a cutaway view of a main part of an optical connector ferrule for explaining a seventh embodiment of the present invention. FIG. 7A shows a main body side ferrule portion 23 and a front end side ferrule portion 24. (B) shows a state where the main body side ferrule portion 23 and the front end side ferrule portion 24 are connected and abutted, respectively, and (C) and (D) show a front end of the ferrule main body for an optical connector. Is an enlarged cross-sectional view of a main part, and (E) is a front view of the main part also cut. The same symbols as those used in FIGS. 1 to 6 represent the same parts or have the same meaning.

As shown in the figure, the structure of the seventh embodiment is substantially the same as that of the sixth embodiment.
Frusto-conical portion 24C in distal ferrule portion 24
A rail groove 24L is formed on an exponentially curved surface of the ferrule sleeve 22, and a leaf spring 29 provided at the tip of the ferrule sleeve 22 is inserted into the rail groove 24L.

Accordingly, the rail groove 24L plays a role of guiding the leaf spring 29 and a role of preventing the tip side ferrule portion 24 from rotating in the ferrule sleeve 22.

FIG. 8 is a perspective view of an essential part showing a ferrule for an optical connector for explaining an eighth embodiment of the present invention. The same symbols as those used in FIGS. 1 to 7 denote the same parts. Or have the same meaning.

The configuration of the eighth embodiment is different from the other embodiments in that a plurality of slits 22B extending in the longitudinal direction are cut at the tip of the ferrule sleeve 22 to give some elasticity. With this configuration, it is possible to increase the diameter at the tip of the ferrule sleeve 22, so that the tip side ferrule portion 2
When mounting the ferrule 4 in the ferrule sleeve 22, the ferrule 4 can be fitted from the outside, and the assembly becomes very easy.

[0054]

According to the ferrule for an optical connector according to the present invention, a cylindrical main body ferrule portion holding an optical fiber in a central through hole, and a cylindrical ferrule portion fixed to the main body side ferrule portion. The ferrule includes a sleeve and a cylindrical distal ferrule portion that is cylindrical and holds the optical fiber in the central through hole and is inserted into the ferrule sleeve and is slidable in the central axis direction.

By adopting the above configuration, when the optical connector is removed from the optical transmission device, the optical output from the tip of the optical connector is automatically reduced, and the function of preventing the danger can be sufficiently achieved. The shape and dimensions can be exactly the same as standard ferrules that have been widely used in the past. Therefore, the ferrules according to the present invention can be substituted for ferrules in conventional optical connectors and used without any change. be able to.

[Brief description of the drawings]

FIG. 1 is an essential part perspective view showing an optical connector for describing Embodiment 1 of the present invention.

FIG. 2 is a fragmentary side view showing an optical connector for explaining Embodiment 1 of the present invention;

FIG. 3 is a cutaway side view of a main part showing a ferrule for an optical connector for describing various embodiments.

FIG. 4 is a cutaway side view showing a main part of an optical connector ferrule for explaining Embodiment 4 of the present invention;

FIG. 5 is a cutaway side view showing a main part of an optical connector ferrule for explaining Embodiment 5 of the present invention;

FIG. 6 is a fragmentary explanatory view showing a ferrule for an optical connector for describing Embodiment 6 of the present invention.

FIG. 7 is a cutaway view of a main part showing a ferrule for an optical connector for explaining Embodiment 7 of the present invention.

FIG. 8 is a perspective view of an essential part showing a ferrule for an optical connector for explaining an eighth embodiment of the present invention;

FIG. 9 is a main block diagram showing an optical output cutoff circuit.

FIG. 10 is a side view showing a main part of a conventional optical fiber connector having a light blocking structure.

[Explanation of symbols]

 Reference Signs List 21 Ferrule for optical connector 22 Sleeve for ferrule 22A Inward protruding edge 23 Main ferrule part 24 Front ferrule part 24A Large diameter part 24B Small diameter part 25 Optical fiber 26 Adapter for optical connector 27 Ferrule for opposed optical connector

Claims (8)

[Claims] 1. A cylindrical ferrule portion holding an optical fiber in a central through hole, a cylindrical ferrule sleeve fixed to the main body ferrule portion, and an optical fiber held in a central through hole. A ferrule portion for an optical connector, comprising: a cylindrical ferrule portion which is formed in a cylindrical shape and is slidably inserted in the ferrule sleeve in a central axis direction. 2. The ferrule for an optical connector according to claim 1, wherein opposing connection end faces of said main body side ferrule portion and said front end side ferrule portion are PC polished surfaces. 3. The optical connector according to claim 1, wherein the main ferrule portion and the distal ferrule portion are oblique PC polished surfaces that bend in an optical path in a state where opposing connection end surfaces are separated from each other. For ferrule. 4. The ferrule according to claim 1, wherein a coil spring is interposed between the distal end of said ferrule sleeve and said distal ferrule to urge said distal ferrule from said main ferrule. Item 2. The ferrule for an optical connector according to Item 1. 5. The light according to claim 1, wherein a coil spring is interposed between the main body side ferrule portion and the distal end side ferrule portion in the ferrule sleeve so as to be separated. Ferrule for connector. 6. A ferrule for an optical connector according to claim 1, wherein a slit is formed at a distal end of said ferrule sleeve so as to increase a diameter when said distal ferrule portion is fitted. 7. A ferrule sleeve has a leaf spring fixed to a distal end thereof, and the leaf spring abuts on a frusto-conical portion formed at the distal ferrule portion to move from the main body ferrule portion to the distal ferrule. The ferrule for an optical connector according to claim 1, wherein the ferrule is urged to separate the portions. 8. The optical connector according to claim 7, wherein a frustoconical portion of said tip side ferrule portion to which said leaf spring comes into contact has a rail groove for receiving a part of said leaf spring. Ferrule.