JPS5858511A - Plug for optical connector - Google Patents

Abstract

PURPOSE:To guide an optical fiber cable so that it is curved gently, by providing a continuously expanding tail part in the rear end of a plug. CONSTITUTION:A continuously expanding tail part 7 having a constant curvature radius R and a center angle THETA is provided in the rear end of a plug 1. The center angle THETA is set to 70-180 deg.. The curvature radius R is determined properly in accordance with materials and the diameter of a fiber 23. Thus, an optical fiber cable 20 is guided so that it is curved gently.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical connector plug that is attached to the end of an optical fiber used for optical communication and the like and is attached to an optical connector.

FIG. 6 shows a cross-sectional plan view of a conventional optical connector plug.

The conventional plug 31 is made of metal and has a front cylinder part 32 and a rear cylinder part 3.
3 and an intermediate flange 34, and has an elongated cylindrical shape.

The inner diameter of the plug 31 is formed with a space whose inner diameter decreases stepwise.

A stripped optical fiber cable is inserted and fixed into this space. A covered cord 20 is glued to the rear of the collar 34. Further forward, a reinforcing member 21 with the coating removed is inserted. The fiber core wire 22 is housed further forward. The fiber wire 23 obtained by removing the protective layer from the fiber core wire is stored further forward.

Such an optical connector plug 31 has the following drawbacks.

It is fine if the optical fiber cord is kept straight, but sometimes it is bent. When bent,
The plug 31 is bent by the rear end edge 35 with a small radius of curvature. Since the cord 2o is made of flexible resin, it has the effect of maintaining a large radius of curvature. However, if the tensile force applied to the cord is strong, the trailing edge 35
The cord will be bent strongly by the corner of the cord.

Optical fiber wires are made of quartz, glass, plastic, etc., and may break if repeatedly subjected to excessive bending.

In order to prevent excessive curvature 36 near the rear end edge 35 of the plug as shown in FIG.
It would also be possible to use this member to prevent the cord from bending.

Generally, after a plug is fixed to the end of an optical fiber cable, the plug is often attached to an optical connector made up of several members. Therefore, an optical connector (not shown)
It is possible to provide a member inside or outside of the optical fiber cable to prevent bending of the optical fiber cable.

However, there is also a possibility that the optical fiber cable may be used with only the plug fixed to it. Furthermore, after the plug is fixed but before it is installed in the optical connector, the optical fiber cable may be subjected to excessive tensile force and be bent strongly. The steps of fixing the plug and attaching the optical connector are not necessarily performed consecutively.

The present invention addresses these problems and provides a plug for an optical connector in which a continuous diameter-expanding tail is formed on the tail of the plug itself to guide the optical fiber cable in a gentle curve.

Hereinafter, the configuration, operation, and effects of the present invention will be explained with reference to drawings showing examples.

FIG. 1 is a plan view of an optical connector plug according to an embodiment of the present invention, and FIG. 2 is a cross-sectional plan view.

FIG. 3 is a cross-sectional plan view showing a state in which an optical fiber is fixed to the optical connector plug. Figure 4 shows a front view.

The optical connector plug 1 has a front cylinder part 2 in the first half, a rear cylinder part 3 in the second half, and a collar part 4 in the middle.

The front part of the front cylinder part 2 has a tapered surface 5. This is for inserting into a cylindrical member (not shown) housing a light emitting element such as a light emitting diode or a laser diode, or a light receiving element such as a photodiode or avalanche photodiode.

There is a circumferential notch 6 in the middle of the tapered surface 5.

A feature of the plug of the present invention is that it is provided with a diameter-expanding tail portion 7 that continuously expands in diameter at the rear end. In this example, the enlarged diameter tail portion 7 is provided with a uniform radius of curvature in the cross section.

The plug 1 is hollow, and the lower end of the optical fiber can be fixed therein.

That is, the hollow part of the rear cylinder part 3 serves as a cord chamber 8 with a wide inner diameter. A reinforcing material chamber 10 is located in front of the cord chamber 8 via a short tapered portion 9 whose diameter is reduced.

A core wire chamber 12 is provided further forward of the reinforcing material chamber 10 via a short tapered portion 11 whose diameter is reduced.

Further forward of the core wire chamber 12, there is a short tapered part 1 whose diameter is reduced.
A strand chamber 14 is provided via 3. The inner diameter of the strand chamber 14 is the narrowest and communicates with the predecessor outlet 15.

In FIG. 3, which shows a state in which an optical fiber cable is fixed to the plug 1, the coating of the optical fiber cable is peeled off sequentially from the tip.

An unpeeled cord 20 is inserted into the cord chamber 8. A reinforcing material 21 is inserted into the reinforcing material chamber 10.

The fiber core wire 22 is housed in the core wire chamber 12 .

The fiber strand 23 passes through the strand chamber 14 .

In this example, a cord chamber 8, a reinforcing material chamber 10, a core wire chamber 12,
The inner diameter of the wire chamber 14 is 2.4■, 1.1wn, O,'1m
m, 0.3 scratches.

Also, the length of the front cylinder part 2 is 9.5m, and the length of the collar part 4 is 1a+
m, the length of the straight part of the rear cylinder part 3 is 10 m.

In the same example, the outer diameter of the cord 20 is 2.2 mm, and adhesive 16 is filled between the cord and the inner wall of the rear cylinder portion 3.

The effects of the present invention will be described.

The preg of the invention has a continuously expanding tail 7 at the rear end. Therefore, even if an optical fiber cable is subjected to a strong tensile force in the lateral direction, it will bend gently. The state of curvature is determined by the shape of the inner surface of the continuously expanding tail 7 of the plug.

In this embodiment, in the cross-sectional view of FIG. 2, the continuously enlarged diameter tail portion 7 has a constant radius of curvature and exhibits an arcuate cross section with a central angle of θ.

The product KO of the radius of curvature R and the central angle θ represents the length of the continuously expanded tail portion 7. θ is determined according to the maximum angle at which the optical fiber cable can be pulled diagonally. For example, θ is preferably 70° to 180°.

An example in which θ=180° is shown in FIG.

The radius of curvature is appropriately determined depending on the material and diameter of the fiber wire 23.

Generally, the diameter of the fiber wire is about 0.05 to 0.3 m. The thinner the material, the more it can withstand strong bending.

For example, in the case of a quartz optical fiber, when the diameter of the fiber wire is 0.15 mm, the radius of curvature may be 1.5 to 2 degrees or more.

When the diameter of the fiber wire is o, 3WrIn, it is desirable that the radius of curvature is 3 to 4 mm or more.

According to the present invention, since the optical fiber cable is bent with such a large radius of curvature, the optical fiber will not break even if it is bent repeatedly.

In the above example, the radius of curvature R of the continuously enlarged diameter portion in a plane including the center line was constant.

However, the radius of curvature k does not necessarily need to be constant.

Let the axial direction of the plug be the Z axis, the radial direction be r, and the angular direction be θ.

An arbitrary point P on the inner wall of the continuously expanding tail section is defined as (r.

θ, z).

In the above example, since the continuously expanding tail portion 7 has rotational symmetry, it can be written as r □20(1) aθ. In other words, the continuously expanding diameter tail portion 7 is r = T(Z)
It can be expressed in the form (2). θ
Does not include.

, and the curvature of one person is In the above example, it was a constant value.

However, these conditions are not necessarily required.

Due to the nature of the optical fiber cable, a minimum radius of curvature Rjth is required to prevent it from breaking.

Therefore, the continuously expanding tail portion 7 may have a shape that has no rotational symmetry and can be written as r = r (Z, θ) (4) depending on the angle θ, but for all θ and Z, the second partial differential It is sufficient if the inequality holds true.

However, equation (5) does not have to hold true in an infinitesimal area. In other words, there may be a discontinuous point with a gradient a''/al, but the area of the discontinuous point must be infinite.

Then, the inequality (5) must hold for a finite region of Z, and for one in an infinitesimal region, the inequality (5) must hold true for a finite region of Z.
) does not have to hold true. However, since the inner peripheral surface must be continuous, r must be a continuous function of Z.

Also, at the starting point I of the continuously expanding tail portion 7, An initial condition is imposed.

These three conditions, namely, inequality (5), r is a continuous function of Z, 1. What satisfies the initial condition (6) can be expressed as ``J whose diameter expands continuously in the positive direction of S''.

Here, S is the length from the starting point I to the measured point P, and is a quantity defined by s-f V(az')2+(dr)2(7).

In short, the optical connector plug of the present invention does not need to have rotational symmetry, and the radius of curvature K does not need to be constant.

It is sufficient to simply expand the diameter continuously. The degree of diameter expansion is limited by the inequality (5).

[Brief explanation of drawings]

FIG. 1 is a cross-sectional flat view of an optical connector plug according to an embodiment of the present invention. Figure 3 shows the state where the optical fiber cable is inserted and fixed into the optical connector plug.
．． . . ,. . FIG. 5 is a cross-sectional plan view of an optical connector plug showing an embodiment in which the center angle of the curved diameter-expanding tail portion is 180°. FIG. 6 is a cross-sectional plan view of a conventional optical connector-plug in which an optical fiber cable is inserted and fixed. 1... Plug 2... Front cylinder part 3... Rear cylinder part 4... Flam part 5... Taper surface 7...・・Continuous diameter expanding tail portion k・・・・Curvature radius θ of the curved portion・・・Maximum central angle 2 of the continuous diameter expanding tail portion・・・・・
・Axial coordinate (backwards) θ...Phase angle coordinate r...Radial coordinate S...Length from starting point I Inventor: Tadashi Moriyama Toshio Wasinohara Sugi 'Tetsuo Moto Patent Applicant Toyota Motor Corporation Figure 2 Figure 1 A Figure 3

Claims (1)

[Claims] An optical connector plug characterized by having a continuously expanding diameter tail section at the rear end.