JPS6230206A - Soldering method for optical connector - Google Patents

Abstract

PURPOSE:To improve the adhesion reliability by soldering by applying a preliminary solder coating to a fiber communicating hole in a ferrule and/or an optical fiber end part. CONSTITUTION:The ferrule 83 or an optical cord 81 is held by a clip 45a or a clip 45b, and inserted into a molten solder 91 in a solder pot 89 vibrated vertically by a ultrasonic vibrator. Then the inner periphery of the fiber communicating hole 83f and the outer periphery of the optical fiber 81a are soldered to execute the preliminary solder coating. Due to the ultrasonic vibration and thermal conduction given through a core chip 87 in the solder pot 89, the molten solder rises through the fiber communicating hole of the ferrule, whereby the fiber communicating hole 83f or the periphery of the optical fiber 81a is sequentially melted. Then the ferrule 83 and the optical fiber 81a are securely solder- fixed in a short time by the preliminary coat soldering.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a soldering method for optical connectors using ultrasonic waves, in which a ferrule to be soldered and a soldered part of an optical fiber are coated with solder in advance. Regarding.

[Prior art] In the conventional soldering method for optical connectors, Japanese Patent Application Laid-Open No. 5L129
As shown in Japanese Patent No. 816, the tip of an optical connector (ferrule) is inserted into the melted solder in the solder pot provided on the ultrasonic vibrator while applying a sonic vibration.
Methods are known for securing optical fibers inserted within ferrules.

[Problems to be solved by the invention] In the conventional method as described above, it is not possible to confirm whether or not the solder has sufficiently penetrated into the minute gap, the reliability of adhesion is low, and the solder is not used unnecessarily. In addition to increasing the reliability even a little by taking more time to attach the ferrule, the long preheating time of the ferrule and the long immersion time in the solder pot can cause the ends of the optical cord's coating resin to melt or become deformed. There were drawbacks such as:

[Means for Solving the Problems] The present invention solves the above-mentioned problems by inserting an optical fiber inside the core chip which is subjected to ultrasonic vibration in a solder pot containing melted solder. This method is characterized in that a preliminary solder coating is applied to either or both of the peripheral surface of the optical fiber and the inside of the fiber insertion hole of the ferrule.

[Operation] Due to the ultrasonic vibration and heat conduction applied through the core chip in the solder pot, molten solder rises from the fiber insertion hole of the ferrule.

The solder pre-coated on the fiber insertion hole or the circumferential surface of the optical fiber is sequentially melted, and the ferrule and the optical fiber are reliably and quickly soldered and fixed by the pre-coated solder.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings. Figs. 1 to 3 are side views of main parts of an apparatus for carrying out the present invention, and in this example, one main body table 1 is shown. A molten solder bath 3 and a connector holding device 5 are provided protrudingly above.

The connector holding device 5 is provided with two parallel lifting guide rods 9 (9a, 9b) that stand upright on a rotary table 7 that horizontally rotates at a constant angle on the table 1 so as to be able to rise and fall freely. A rectangular flat box-shaped casing 13 and a lower casing 16 that fits into the casing 13 are provided on the outer periphery of the lifting rod 9, and the lower casing 16 is fastened and fixed on the rotary table 7 by a port 17. .

A spring receiver 19 made of a snap ring or the like is provided in the shape of a flange on the upper part of the lifting roller 9 between the upper and lower bearings 15, 15, and a coil spring 21 is inserted into the lower part of the spring receiver 19 by being sheathed on the rod 9. Both elevating rods 9 are always biased upward, and when the rods 9 are lowered, they are raised by themselves by the push-up blades of the springs.

The lifting lodges 9a and 9b are always driven up and down at the same time,
The upper end protrudes above the casing 13, and the lower end protrudes above the casing 1.
A sleeve-shaped stopper 27, which is inserted into the lifting block 22 and is adjusted up and down by the adjusting screw 23 screwed into the center thereof and is integrated with the knob 25, hits the bottom surface of the lifting block 22, and the stopper 27 is integrated with the adjustment screw 23 screwed into the center of the stopper The lower limit positions of the block 22 and the rod 9 are adjusted and regulated. In addition, the upper limit position of the lifting block 22 is the bearing 1 in the upper part of the casing 13.
The spring receiver 18 is determined by coming into contact with an O-ring 28 provided at the lower part of the spring 5.

An upper base 33 is fastened and fixed onto the lifting block 22 by a fixing port 31 inserted from the lower part thereof, and two guide rods 35 (front and rear) are mounted on the upper base 33.
a, 35b) are fixed upright in parallel, and a top plate 37 corresponding to the upper base 33 is fixed to the upper end of the guide rod 35.

Two clips 41 and 43 are attached to the guide rod 35a in front of the guide rod 35 via bearings 38 such as bearings or bushings so as to be movable up and down. The above-mentioned clips 41 and 43 have almost the same structure except for the shapes of the optical cord or ferrule gripping parts 45a and 45b attached to the tips, so below, the same parts in both will be denoted by the same reference numerals, mainly the lower part. The structure of the ferrule gripping clip 41 will be explained.

As shown in FIGS. 1 and 2, the clip 41 is horizontally fitted and fixed to the bearing 38 at a constant interval vertically, and its rear end is fitted to the rear guide rod 35b so as to be movable up and down. A pair of clip levers 51.51 are rotatably supported by shafts 53, 53 between the upper and lower plates 47, 49.
Gears 55.55 meshing with each other between the shafts 53.
53 and the lever 51°51.

As a result, the levers 51, 51 always operate symmetrically, and the centers of the grips 45a, 45b are always kept constant.

Further, sleeve-shaped spacers 57a and 57b are fitted to the tips of the plates 47 and 48, and the spacers 57
a and 57b are the guide rods 35a.

It is inserted through an adjuster bolt 59 parallel to 35b so as to be able to move up and down. The upper end of the adjuster bolt 59 is screwed into and inserted into a sleeve-shaped tension lock 61 having a flange-shaped spring receiver 61a at the lower end, and the tension lock 61 is fitted to the tip of the top play 1/37 so as to be able to rise and fall freely. There is.

Also, L Top Brake) 37,1. A sleeve-shaped tension adjuster 63 is fitted into the upper end of the tension lock 61 protruding from the top, and the lower end of the tension adjuster 63 comes into contact with the upper surface of the top play 1/37, and the adjuster bolt 59 is attached to the upper end of the tension adjuster 63. The top end is screwed through. A coil spring 65 is mounted on the top plate 37 and the tension lock 61.
is inserted, and the tension lock 61 is raised and lowered together with the adjuster bolt 59 by turning the tension adjuster 63, and thereby the downward pressing force of the spring 65 is adjusted.

The clip 41 is provided with a clip adjustment ring 67 inserted through the adjuster bolt 59 and a ring stopper 69 consisting of a nut screwed into the adjuster bolt 58 on the upper surface, and protrudes above the tip of the lower base 33. A clip stopper 71 made of a bolt is screwed in so as to be adjustable. Further, a bottle-shaped spring hook 73 is protruded from the tip of the upper clip 43, and as shown in FIGS. 1 and 3, two hairpin-shaped pressing rods 75a,
75a and a ring-shaped coil portion 75b as a connecting portion at one end thereof.
A coil portion 75b of the retaining spring 75 is fitted into the spring hook 73, and the coil portion 75b of the retaining spring 75 has bent portions 75c, 75c whose other ends intersect with each other and face each other.

On both sides of the peripheral wall of the spacer 57b protruding onto the upper plate 48 of the upper clip 43, the engagement springs 75 are provided.
Pressing rod 75a, ? A slit 77 is provided in which the 5a is constantly inserted by the action of an inward force, and the pressing rod 75a,
75a is pressed against the adjuster bolt 59 with a certain elasticity, and the clip 43 is supported by the adjuster bolt 59 by the frictional force of this pressing. However, if a vertical force stronger than the above-mentioned pressing frictional force is applied, The clip 43 moves up and down. Similarly, bent portions 75c, 75c are formed from both sides.
When the pressing rods 75a, 75a are pushed apart and the pressing force on the adjuster bolt 59 is released, the clip 43 can freely move up and down.

On the opposing surface near the rear end of the clip lever 51.51, there is a mark (
That is, when a spring 79 is inserted that urges the grip 45a or 45b to close, and the clip lever 51 or 510 is pressed inside the rear end against the spring 79,
The grip portion 45a or 45b at the tip opens, and when released, is closed by the bias of the spring 78.

The gripping portion 45a or 45b of the clip 41.43 is always on the same axis, and the gripping portion 45a or 45b of each clip 41.43
a and 45b are the ferrule 83 and the optical cord 81, respectively.
are held coaxially with the ground, and a molten solder tank 3 is located below these axes.

That is, a core chip 87 connected to the tip of a horn 85 connected to an ultrasonic transducer (not shown) at the bottom thereof is housed in the solder bath 3 facing upward, and a solder pot equipped with a heating device is placed around the core chip 87. Inside the solder pot 88, a molten solder 91 containing Sn, Pb, Zn, or a rare earth element added thereto and having excellent adhesion to glass or ceramics is housed. At the center of the upper end of the core chip 87, a relief portion 93 consisting of a hole with a diameter of about 1 inch is formed, and the center of the relief portion 93 is located at the grip portion 45a.

It is located on the downward extension of the axis of 45b.

The ferrule 83 constitutes the main part inserted into the interior of the optical connector, and in the illustrated example, as shown in FIG.
3b, an optical cord insertion hole 83c passes through the center of the interior thereof, and a stepped portion 8 is provided at the lower end of the insertion hole 83c.
3d is formed, and a sleeve-shaped capillary 83e made of ceramics or the like is fitted and fixed therein. An optical fiber insertion hole 83f of about 12 g tm is bored in the center of the capillary 83e. This cabilary 8
There is also a type in which the optical cord insertion hole 83c is continuous to the fiber insertion hole 83F without providing the hole 3e.

The fiber insertion hole 83f is located at the center of the optical cord 81.
An optical fiber 81a that is fitted with an accuracy of about 1 l diameter is housed with a silicone coat 81b, and its outer periphery is coated with a resin coating 81c such as nylon. At the tip of the optical cord 81 inserted and fixed into the ferrule 83, an optical fiber 81a projects for a length longer than the capillary 83e.

Next, the first method of connecting the optical cord 81 and the ferrule 83 will be explained. For example, as shown in FIGS. 4 and 5, the ferrule 83 or the optical cord 81 is held by the clip 45a or 45b, and the ultrasonic The core chip 8 generates vertical vibrations of lO~100KHz using a vibrator.
These preliminary solder coats are inserted into the melted solder 91 in the solder pot 89 provided through the solder pot 7, and are applied with solder to the inner circumferential surface of the fiber insertion hole 83f and the outer circumference of the optical fiber 81a to perform a preliminary solder coat. This can be done by any method, but when immersing the ferrule 83 in the melted solder 91, a heat-resistant resin tube 85 (
It is desirable to cover the ferrule with a shrink tube (preferably a shrink tube) to protect the precision-machined periphery of the ferrule.

After the preliminary solder coating is completed, the upper end of the ferrule 83 and the optical cord 81 are held concentrically by the gripping part 45a at the tip of the clip,
45b to grip it. At this time, the optical fiber 81a is not inserted into the ferrule 83.Then, the lifting block 22 is lowered, and the tip of the ferrule 83 is inserted into the solder pot 89 where ultrasonic vibration is being applied, and it comes into contact with the center of the core chip 87. urge

In this process, the preliminary solder in the fiber insertion hole 83f of the ferrule 83 has been melted, so the bent portion 75c of the engagement spring 75 on the clip 43 is pressed from both sides and the pressing rod 75
a from the adjuster bolt 58, and insert the tip of the optical cord 81 into the ferrule 83 while lowering the clip 43. At this time, the preliminary solder coat on the outer periphery of the optical fiber 81a is also melted as the optical fiber 81a is inserted, and the ultrasonic vibrations applied to the ferrule 83 cause the optical fiber 81a to be placed at the center of the entrance of the fiber insertion hole formed in a forest shape. As a result of the tip being guided, the optical fiber 81a is smoothly inserted into the fiber insertion hole 81F, and the tip of the optical fiber 81a is accommodated in the escape portion 93.

At the time when the optical fiber 81a is inserted into the fiber insertion hole 83f, the retaining spring 75 is released from the open state, and at this position, the clip 43 is gently moved to the regular position of the adjuster bolt 59. Fixed to. At this time, adjust the ring stopper 69 to provide a certain gap between the ring stopper 69 and the top surface of the clip 41.
When the small stroke of the lifting block 22 is repeated,
The molten solder fits between the optical fiber 81a and the fiber insertion hole 85f, and the molten solder uniformly penetrates into the gap between the two by ultrasonic vibration.

Finally, the optical cord 81 and the ferrule 83 are ultrasonically soldered while the ferrule 83 is brought into contact with the core chip 87 and the lifting block 22 is strongly suppressed downward. At this time, the upper clip 43b also protrudes from the upper part. The lower end of the tension lock 81 is connected to the spacer 57b by the spring 6 adjusted by the tension adjuster 63.
5, and the optical cord 81 is also subjected to its own downward pressing force.

With both the optical cord 81 and the ferrule 83 pressed downward as described above, ultrasonic vibration causes microscopic (
Soldering is performed by pushing up the melted solder into the gap (for example, IJLII), and the solder solidifies in 2 to 3 seconds by raising the lifting block 22. After the raising, the optical cord 81 and ferrule 8
3 is removed, the resin tube 95 is removed, and the resin tube 95 is sent to the next processing step.

During the soldering process, in order to prevent the resin coating part 81c from melting due to the heat of the melted solder transmitted to the ferrule 83, the grip part 45a at the tip of the clip 41 is made of a material with good heat dissipation conductivity (i.e., a high heat dissipation effect). It is desirable to choose the material.

Further, by applying preliminary solder coating to either the fiber insertion hole 83f or the optical fiber 81a, a sufficient effect can be obtained to perform soldering evenly, with high strength, and in a short time.

Next, the second soldering method for fixing the optical cord 81 and ferrule 83 will be explained based on FIG.
The jet nozzle 97 penetrates the jet hole 97a at position w,
The nozzle guide 99 is placed concentrically and in contact with the upper surface of the core chip 87 so that the contact surfaces thereof fit into each other, and the nozzle guide 99 is fitted so that the jet nozzle 87 maintains a fixed position on the core chip 87. A jet soldering device installed on the peripheral wall is used.

In this device, when ultrasonic vibration is applied to the core chip 87, solder enters from the contact surface between the core chip 87 and the jet nozzle 87, and as a result, the molten solder 81 is jetted onto the upper end surface of the nozzle 97 through the jet hole 97a. Soldering is performed by pressing the optical cord 81 against the ferrule 83, which has been pre-soldered on the upper surface of the jet nozzle 97 projecting above the liquid surface, in the manner described above.

That is, when the ferrule 83 and the optical cord 81 are pressed against the center of the upper end surface of the nozzle 87 where the molten solder 91 is jetted in the manner shown in FIG. The end has a jet hole 97
The jet solder enters the minute gap between the optical fiber 81a and the inner surface of the fiber insertion hole 83f from the end face of the ferrule, and soldering is performed while melting the preliminary solder coat.

According to this method, melted solder does not adhere to the circumferential surface of the ferrule 83, and there is no need to cover the ferrule tip with a resin tube as shown in FIG. 6, or to remove adhering solder from the circumferential surface. There is no heat effect from melted solder on the ferrule or optical cord.

Preliminary solder coating of the ferrule 83 and the optical cord 81 can also be performed by pressing the ferrule 83 against the end face or inserting the optical fiber 81a into the solder pot 89 or jet hole 97a.

In this second method as well, it is sufficient to apply preliminary solder coating to only one or both of the ferrule 83 and the optical fiber 81a.

In any of the above methods, it is also possible to perform the final soldering after the optical fiber 81a is inserted halfway into the ferrule 83 and temporarily fixed in the preliminary solder coating process.

A preferred embodiment of a method for pre-soldering the fiber insertion hole 83F of the ferrule will be described with reference to FIGS. 9 and 10.

A sensor 100 for detecting completion of preliminary solder coating is inserted into the optical code insertion hole 83C of the ferrule 83 from above. This sensor is provided with a stopper 101, and when the stopper comes into contact with the upper end of the ferrule, the tip of the sensor is positioned at the upper end of the optical fiber insertion hole 83f. Next, this ferrule is gripped by the gripping portion and lowered to come into contact with the upper end surface of the jet nozzle 97. Melted solder 91 is jetted from a jet hole 97a on the upper end surface of the jet nozzle due to ultrasonic vibration, and when the lower end surface of the ferrule comes into contact with the jet nozzle, this molten solder enters into the fiber insertion hole 83f of the ferrule, forming a preliminary solder. A court is held. When the melted solder reaches the upper end of the fiber insertion hole 83F, conduction between the sensor 100 and the solder pot 89 is detected, and the application of ultrasonic vibration is automatically stopped, completing the preliminary solder coating. This sensor is
A heat-resistant insulating layer 103 is provided on the outer peripheral surface of a copper wire 102, and the tip thereof is slightly exposed. This insulating layer is preferably made of polyimide resin, silicone resin, or fluororesin, which has heat resistance that does not deteriorate at working temperatures and has insulation properties at the working temperatures.

The sensor is not limited to this, for example, it may be configured to detect conduction with the molten solder in the solder pot 89, and two conductive wires that are insulated from each other are exposed at their tips, and the molten solder adheres to the exposed portion. Continuity can also be detected by this.

Further, the solder bath may be of a type in which the upper end surface of the core chip 87 is below the surface of the molten solder bath, as shown in FIG. 4, and the ferrule is immersed in the molten solder bath and comes into contact with the core chip.

It is particularly preferable to use a sensor to detect the completion of the preliminary solder coating in the fiber insertion hole, since this eliminates soldering defects due to insufficient preliminary solder coating, making it easier to perform stable work.

[Effects of the Invention] The present invention produces effects similar to those of the resultant method configured as described above.

(1) Since the fiber insertion hole in the ferrule and/or the end of the optical fiber are coated with preliminary solder, the reliability of solder bonding is high.

(2) There is a small diameter (125 mm) inside the ferrule that is vibrating ultrasonically.
Since the optical fiber is passed through the optical fiber at the position (kla), the fiber tip will not come into contact with the entrance of the fiber insertion hole and prevent insertion, breakage, deformation, etc., and it will be guided smoothly and inserted in a short time, and it will be inserted easily. Since the dissolution rate of the preliminary solder coat is faster than the rate at which new solder enters into the minute gap in the hole, the soldering rate becomes faster by that amount, which has the advantage of shortening the soldering work as a whole.

(3) Combined with the shortened soldering process, there is less temperature rise in the ferrule, especially at its upper end, and the resin coating of the optical cord melts due to heat (note: 120℃ for nylon coatings, etc.)
Solder having a melting point of ~130° C.) is reduced, and it becomes possible to use solder with a high melting point.

(4) When pre-soldering the fiber insertion hole, if the sensor detects the completion of the pre-soldering cord and stops the application of ultrasonic vibration, there will be no soldering defects and stable work can be performed easily. Particularly preferred.

[Brief explanation of drawings]

Fig. 1 is a partial cross-sectional view of the main parts showing an embodiment of the ultrasonic soldering device, Fig. 2 is a half-sectional plan view showing the clip structure, and Fig. 3 is the structure of another engagement spring on the upper part of the clip. 4 to 7 are enlarged sectional views of main parts showing the soldering method. FIG. 8 is an enlarged sectional view showing an example of the structure of an optical cord and a ferrule that are fixed to each other. FIG. 9 is an enlarged sectional view of an optical Enlarged sectional view of the device for applying preliminary solder coating to the fiber insertion hole, No. 10
The figure is an enlarged cross-sectional view of the sensor. Two main body tables 3: Melted solder bath 5: Connector holding device 7: Rotary table 9 (9a, 9b):
Lifting a +7 do 13: Casing 15: Bearing
16: Lower casing 19: Spring receiver 2
1: Coil spring 22: Lifting block 23: Lifting screw 25: Adjustment knob 27: Stopper 29: 0 ring 31: Fixed port 33: Upper base 35 (35a, 35b) Two guide rods 37 Two top plates 39: Bearings 41, 43: Clip 45a, 45b: Grip portion 47.49 Nibrate 51: Clip lever 53:
Shaft 55: Gears 57a, 57b: 7. Pacer 58: Adjuster bolt 61: Tension lock 61a: Spring receiver θ3: Tension adjuster 65 spring 67: Ring 69 Ni ringest collar 71: Clip stopper 73: Spring hook 75: Engagement spring 75a: Pressing rod 75b: Coil part
75C: Bend part 77: Slit 79 Spring 81: Optical cord 81a: Optical fiber 8
1b=Silicone coat 81c: Covering portion 83: Ferrule 83a: Main body 83b: Flange
83c: Optical cord insertion hole 83d: Stepped part
83e: Capillary 83': Fiber insertion hole 85:
Horn 87: Core chip 89: Solder pot 9
1. Melting hang 93: Relief part 95: Heat-resistant resin tube 97: Jet nozzle 97a; Jet hole 99: Nozzle guide 100: Sensor No. 2 Diagram 4 Diagram 5 Diagram 6 Diagram 9 Diagram 0

Claims (2)

[Claims] (1) In a method in which the lower end of a ferrule, into which an optical fiber is inserted, is brought into contact with a core chip that is subjected to ultrasonic vibration in a solder pot containing molten solder, the peripheral surface of the optical fiber is soldered. A method for soldering an optical connector, characterized by applying a preliminary solder coat to one or both of the fiber insertion holes of the ferrule and the fiber insertion hole of the ferrule. (2) When applying a preliminary solder coating to the fiber insertion hole of the ferrule, a sensor detects the completion of the preliminary solder coating inside the insertion hole and stops the application of ultrasonic vibration. Soldering method.