JPH0776803B2 - How to insert an optical fiber into the fuel - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method of inserting an optical fiber into a pore of a ferrule when assembling an optical connector.

(Prior Art) Conventionally, insertion of an optical fiber into a ferrule of an optical connector is manually performed as shown in FIGS. 2 (a) to 2 (c). Specifically, the optical fiber 1 from which the coating 2 at the tip portion has been removed by a predetermined length is grasped with a finger, and the optical fiber 1 is inserted into the coating insertion portion 5 of the ferrule 3 to form a taper provided at the end of the pore 4. The optical fiber 1 is inserted into the fine hole 4 by the guide action of the guide portion 6 by once abutting its tip against the guide portion 6.

(Problems to be Solved by the Invention) In such a manual insertion operation, it was determined by the fingertip feeling that the optical fiber 1 hits the guide portion 6 or the start of insertion into the pore 4 (see FIG. 2). As shown in b), an excessive axial force is applied to the optical fiber 1 to cause it to bend extremely and break, or
Despite the fact that the tip of the optical fiber 1 is inserted into the pore 4 as shown in FIG. 7C, it is judged by the fingertip that it has not been inserted, and the optical fiber 1 is pulled out and inserted again. It is often the case that the optical fiber 1 is redone, and it takes a long time to insert the optical fiber 1 and also scratches the optical fiber 1.

Further, in the case of a single mode fiber connector having a small core diameter, the ferrule 3 is used to reduce the connection loss.
The amount of eccentricity of the optical fiber 1 in the pore 4 must be 1 μm or less, and the clearance between the outer diameter of the optical fiber 1 and the hole diameter of the pore 4 must be 1 μm or less.

In such insertion into the pores 4 having a small clearance,
It becomes more difficult to insert the guide portion 6 into the pores 4,
Even if it can be inserted into the pores 4, there is contact resistance at the inner wall of the pores 4 and at the entrance of the pores 4, so if the insertion speed is high, an excessive axial force is applied, The optical fiber 1 is buckled and deformed in the vicinity of the entrance of the hole 4, and is broken.
It is often possible to remove the residual fiber in and re-try.

As described above, in the conventional manual insertion work, the insertion time is long because the insertion into the pores 4 is determined by the feeling of the fingertip.
Delicate axial force control for the fragile optical fiber 1 becomes difficult, and there is a problem in that workability is poor due to many unnecessary scratches and breakage.

An object of the present invention is to provide a method for safely and quickly inserting an optical fiber into a pore of a ferrule when assembling an optical connector.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a light having a pore into which an optical fiber whose coating of the tip portion is removed is inserted and a guide portion which introduces the tip of the optical fiber into the pore. In the method of holding the ferrule and the optical fiber of the connector on the same straight line by the holding means respectively and moving one of the ferrule or the optical fiber to the other side by the driving means to insert the optical fiber into the ferrule, the tip of the optical fiber is guided. The drive means is controlled while detecting the axial force of the optical fiber with the axial force sensor so that it does not exceed the preset first axial force upper limit value from immediately before it hits the portion to immediately after it is inserted into the pore. , The optical fiber is set so as not to exceed the second axial force upper limit set to a value larger than the first axial force upper limit from immediately after the insertion of the pores to immediately before the coating tip hits the guide portion. The driving means is controlled while the axial force of the bar is detected by the axial force sensor.

(Operation) In the present invention, the axial force of the optical fiber is set so as not to exceed the preset first axial force upper limit value from immediately before the tip of the optical fiber hits the guide portion to immediately after it is inserted into the pore. The driving means is controlled while being detected by the axial force sensor, and is set to a value larger than the first axial force upper limit value from immediately after the insertion of the pore to immediately before the tip of the coating hits the guide portion.
The drive means is controlled while the axial force sensor detects the axial force of the optical fiber so as not to exceed the axial force upper limit value of.

(Embodiment) FIGS. 1 and 3 to 5 show an embodiment of the insertion method of the present invention. FIG. 1 is a configuration diagram of an insertion mechanism, and FIGS. 3 and 4 are ferrules. FIG. 5 is an explanatory view of an optical fiber insertion position and axial force behavior, and FIG. 5 is an explanatory view of an axial force control method.

In FIG. 1, 1 is an optical fiber, 2 is a coating of the optical fiber, 3 is a ferrule, and the coating 2 at the tip of the optical fiber 1 is removed by a predetermined length. Reference numeral 10 is a clamp portion for holding the optical fiber, 11 is a moving base for finely moving the optical fiber in the axial direction along the support shaft 12, 13 is a stepping motor for driving the moving base 11, and 14 is a ferrule 3. The clamp portion 15 is an axial force sensor directly connected to the ferrule clamp portion 14 and detects the fiber axial force 16 applied to the ferrule 3. Reference numeral 17 is a support base that supports the spindle 12, the stepping motor 13, and the axial force sensor 15 at predetermined positions, and 18 is a drive control unit, for example, a microcomputer, which compares the signal of the axial force sensor 15 with a set axial force to provide a stepping motor. 1 drive control is performed. In this embodiment, the movable table 11, the stepping motor 13, and the drive controller 18 are used to clamp the optical fiber clamp unit.
Ten drive control systems are configured.

In the above insertion mechanism, the optical fiber 1 is held at the predetermined position of the clamp portion 10 and the ferrule 3 is held at the predetermined position of the clamp portion 14, respectively, and the stepping motor 13 is driven to move the optical fiber 1 to the coating insertion portion 5 of the ferrule 3. As shown in FIGS. 3 and 4, the optical fiber tip 1a is inserted into the optical fiber tip 1a.
In most cases, the axial force increases by hitting the tapered guide 6 of the ferrule 3 (Fig. 3 (a)), but a certain axial force Pa
When the optical fiber tip 1a reaches the position (1), the optical fiber tip 1a slides out on the slope of the guide portion 6 and enters the pores 4, so that the axial force temporarily decreases (Fig. 3 (b), axial force Pb).

After this, when the insertion is continued, the optical fiber 1 is inserted into the pore 4, and due to the contact resistance force between the optical fiber 1 and the inner wall of the pore 4, an axial force almost proportional to the fiber insertion length is generated. Then, when the optical fiber 1 is inserted into the entire pore 4, the axial force becomes substantially constant (Fig. 3 (c), axial force Pc).

After this, when the insertion is further continued, the tip 2a of the coating 2 hits the guide portion 6 and the axial force sharply rises when the insertion is completed (δ = δ2) (Fig. 3 (d), axial force Pd). .

As described above, in the process of inserting the optical fiber 1 into the pore 4 of the ferrule 3 when assembling the optical connector, the axial force applied to the optical fiber changes corresponding to each insertion step, so that the axial force is appropriately controlled. As a result, the optical fiber 1 can be inserted safely and without wasteful operation.

The axial force control method by the drive controller 18 will be described below with reference to FIG.

First, until the optical fiber tip 1a hits the guide portion 6 of the ferrule 3, that is, until the insertion length δ becomes δ = δ0, the stepping motor 12 inserts at high speed, and the insertion length δ exceeds δ0 (δ ≧. δ0) By the way, the mode is switched to the slow speed insertion, and the axial force control loop for performing the insertion operation while monitoring the output of the axial force sensor 15 is entered.

The axial force is set in the first stage from immediately before the optical fiber tip 1a hits the guide portion 6 to immediately after being inserted into the pore 4 (δ = δ1), and from δ = δ1 to the coating tip 2a on the guide portion 6. It is divided into the second stage until it abuts (δ = δ2), and the upper limit of the axial force in each of the first and second stages is set to Pmax1 and Pm, respectively.
Ax2, and the lower limit of axial force is Pmin in both stages.

The axial force upper limit Pmax1 in the first stage is a set value for preventing breakage due to excessive bending of the optical fiber 1 when it hits the guide portion 6, and for example, the coating 2 of the optical fiber 1
The buckling load may correspond to the dimension of the removed portion, and the axial force upper limit Pmax2 in the second stage may be the axial force when the coating tip 2a completely abuts the guide portion 6. Further, the lower limit value of axial force Pmin is used for detection when the optical fiber 1 is broken at each stage of insertion, and is at least the third value.
It may be set to a value smaller than the axial force Pb in the figure.

When the insertion length δ is smaller than δ1, the above axial force upper limit value
When the insertion is performed at a constant speed in the axial force range between Pmax1 and Pmax2 and the axial force P becomes larger or smaller than Pmax1 in this range, the insertion is stopped or the optical fiber 1 is once It is retracted by a predetermined amount and reinserted (retry).
This retry is performed only when the axial force P becomes larger than Pmax1, and when the axial force P becomes smaller than Pmin, the optical fiber 1
Is not done because it is broken.

Next, when the insertion length δ becomes δ1 or more, the process proceeds to the second stage, and the insertion is continued within the range where the axial force P is larger than the axial force Pmin and smaller than Pmax2. Axial force P in this range
If Pmax is less than or equal to Pmin, the optical fiber 1 is broken, and therefore the insertion is stopped. If Pmax2 is equal to the coating tip 2a, the coating tip 2a is in contact with the guide portion 6 and the insertion is terminated.

In addition, switching from the high-speed insertion described above to the slow insertion,
The setting signals for the insertion lengths δ0 and δ1 that determine the first and second stages are output from a displacement meter or limit switch (not shown) provided externally even if the number of pulses of the stepping motor 12 is counted and given. May be given.

Further, when the clearance between the pore and the optical fiber is small as in the case of inserting a single mode fiber, the axial force Pb approaches Pa and Pc increases as compared with the case where the clearance is large, so that the above-mentioned first, This can be dealt with by reducing the separation insertion length δ1 in the second stage.

Furthermore, the core diameter is large like multimode fiber,
Large clearance allowance with the ferrule pores (2μ
In the case of m), the axial force Pb when the tip of the optical fiber is inserted into the pore is close to 0, and the contact resistance between the optical fiber and the inner surface of the pore is small, so there is a risk of breakage of the optical fiber. Since the number is small, it is sufficient to control only the axial force upper limit value.

Furthermore, although the optical fiber is moved to the ferrule side in the embodiment, the ferrule may be drive-controlled together with the axial force sensor.

(Effect of the Invention) As described above, according to the insertion method of the present invention, the first axial force set in advance is set from immediately before the tip of the optical fiber hits the guide portion to immediately after it is inserted into the pore. By controlling the driving means while detecting the axial force of the optical fiber with the axial force sensor so that the upper limit is not exceeded, the optical fiber is broken due to excessive axial force when the tip of the optical fiber hits the guide section. Can be prevented, and it is possible to avoid the first gap between immediately after the insertion of the pore and immediately before the tip of the coating hits the guide portion.
The axial force sensor detects the axial force of the optical fiber so as not to exceed the second axial force upper limit value set to a value greater than the axial force upper limit value of The complete insertion of the fiber and the completion of the insertion can be surely confirmed.
Also, once the tip of the optical fiber is inserted into the pore of the ferrule, the insertion will continue.Therefore, as in the case of conventional manual insertion, the insertion / removal into / from the pore due to the ambiguity of the judgment of insertion into the pore. There is an advantage that the operation is eliminated and the insertion time is shortened.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an insertion mechanism that realizes the insertion method of the present invention, FIGS. 2A to 2C are explanatory views of a conventional manual insertion method, and FIGS. 3A to 3D. FIG. 4 is an explanatory diagram of the axial force behavior of the optical fiber in the inserting step, and FIG. 5 is a diagram showing an axial force control flow. In the figure, 1 ... Optical fiber, 1a ... Optical fiber tip, 2 ...
... coating, 2a ... coating tip, 3 ... ferrule, 4 ... pore, 5 ... coating insertion part, 6 ... guide part, 10 ... optical fiber clamp part, 11 ... moving base, 12 ... … Spindle, 13 ……
Stepping motor, 14 …… Ferrule clamp part,
15 …… Axial force sensor, 16 …… Axial force, 17 …… Support base, 18…
... Drive control unit.

Claims (1)

[Claims] 1. A ferrule and an optical fiber of an optical connector having a hole into which an optical fiber having a coating of the tip portion removed is inserted and a guide portion for introducing the tip of the optical fiber into the hole, and the optical fiber are respectively held on the same straight line. In the method of inserting the optical fiber into the ferrule by moving one of the ferrule or the optical fiber to the other side by the driving means, from immediately before the tip of the optical fiber hits the guide portion to immediately after the insertion into the pore. Controls the driving means while detecting the axial force of the optical fiber with the axial force sensor so that the preset first axial force upper limit value is not exceeded, from immediately after the insertion of the pore until immediately before the coating tip hits the guide part. During this period, the driving means is controlled while the axial force sensor detects the axial force of the optical fiber so as not to exceed the second axial force upper limit set to a value larger than the first axial force upper limit. To the optical fiber insertion method into a ferrule, characterized in that.