JP2530816B2 - Optical connector soldering method - Google Patents

Description

The present invention relates to a soldering method for an optical connector using ultrasonic waves, in which a ferrule to be soldered and a soldered portion of an optical fiber are previously coated with solder.

[Prior Art] A conventional optical connector soldering method is disclosed in JP-A-59-12981.
As shown in Japanese Patent Publication No. 6, the tip of the optical connector (ferrule) was inserted while applying ultrasonic vibration to the melting solder in the solder pot provided on the ultrasonic pendulum, and was inserted into the ferrule. A method of fixing an optical fiber is known.

[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 the adhesion is low, and the soldering time is longer than necessary. The reliability of the optical cord must be improved by a little bit, and the end of the coating resin of the optical cord is dissolved or deformed due to the long preheating time of the ferrule and the long immersion time in the solder pot. There was a drawback.

[Means for Solving Problems] A first invention for solving the above problems is to accommodate a core chip 87 that vibrates ultrasonically in a solder pot 89 that accommodates melting solder 91, and In the method of soldering the ferrule 83 and the optical fiber 81a inserted into the optical fiber insertion hole 83f of the ferrule 83 by vibrating melting solder 91, the core chip 87 is formed from a hole of a predetermined depth at the tip. While using the one provided with the escape section 93, the melting solder 91 is present on the tip side, and the lower end of the ferrule 83 is attached to the core chip 87 so that the escape section 93 has the optical fiber insertion hole 83f facing each other. Press down,
The optical fiber 81a and the ferrule 83 are soldered in the optical fiber insertion hole 83f.

Similarly, in the second aspect of the invention, the core chip 87 that vibrates ultrasonically is housed in the solder pot 89 that houses the melting solder 91, and the ferrule 83 and the optical fiber of the ferrule 83 are inserted by the melting solder 91 to which the ultrasonic vibration is applied. In the method of soldering with the optical fiber 81a inserted in the hole 83f, in the tip side of the core chip 87, melted solder is internally formed.
A jet nozzle 97 penetrating a jet hole 97a for guiding and jetting 91 is placed in contact, and a ferrule 83 is pressed against the jet nozzle 97 so that the fiber insertion holes 83f face each other on the jet hole 97a. The optical fiber 81a and the ferrule 83 are soldered inside the insertion hole 83f.

The third invention uses a ferrule 83 having a preliminary solder coat applied by ultrasonic vibration in the optical fiber insertion hole 83f, and the sensor 100 is used to prepare a preliminary solder in the optical fiber insertion hole 83f during the preliminary solder coating. The feature is that the completion of coating is detected and the application of ultrasonic vibration is stopped.

[Operation] According to the present invention, the ultrasonic vibration applied to the core chip 87 causes the melting solder 91 in the solder pot 89 to vibrate ultrasonically, and the ferrule 83 and the optical fiber 81a are ultrasonically vibrated in the optical fiber insertion hole 83f. Soldered.

In the first invention, when the tip of the ferrule 83 is pressed against the tip of the core chip 87 in a state where the optical fiber 81a is projected, the projecting end of the optical fiber 81a remains in the projecting state in the relief portion 93 on the core chip 87 side. Melted solder 91 on the tip side of the core chip 87 is penetrated by ultrasonic vibration between the optical fiber 81a and the inner peripheral surface of the optical fiber insertion hole 83f, and the optical fiber 81a and the ferrule 83 are ultrasonically soldered. It

In the second invention, when the tip of the ferrule 83 is pressed against the tip of the jet nozzle 97, the protruding end of the optical fiber 81a is directly inserted into the jet hole 97a of the jet nozzle 97, and the jet hole is formed by ultrasonic vibration. Melting solder 91 jetted from the jet nozzle 97 to the tip of the jet nozzle 97 penetrates between the optical fiber 81a and the optical fiber insertion hole 83f, and the optical fiber 81a and the ferrule.
83 and are soldered with ultrasonic waves.

Further, in the third invention, since the inside of the optical fiber insertion hole 83f in the above invention is pre-solder-coated, it is melted by contact with the melting solder 91, so that the gap between the optical fiber insertion hole 81f and the optical fiber 81a can be rapidly increased. In addition, the melted solder is surely spread, and soldering of both is performed with high reliability.

Further, in the preliminary solder coat, the completion of the preliminary solder coat is detected by the sensor 100 and the application of the ultrasonic vibration is stopped, so that the soldering defect of the preliminary solder coat is eliminated.

[First Embodiment] A first embodiment of the present invention will be described below with reference to the drawings.
FIGS. 3 to 3 are side views of the essential parts of an apparatus for carrying out the present invention.
In this example, a melting solder bath 3 and a connector holding device 5 are provided on one main body table 1 in a protruding manner.

The connector holding device 5 is provided with two parallel rods 9 (9a, 9b) for elevating guides which are vertically erected on a rotary table 7 which horizontally rotates on the table 1 by a predetermined angle. A rectangular flat box-shaped casing 13 on the outer periphery of the lifting rod 9 and a lower casing fitted with the casing 13.
16 is provided, and the lower casing 16 is fixed to the rotary table 7 by bolts 17.

A spring receiver 19 formed of a snap ring or the like is provided in a flange shape on an upper portion of the elevating load 9 between the upper and lower bearings 15, 15, and a coil spring 21 is inserted into each of the lower portions of the spring receiver 19 so as to be externally mounted on the rod 9. Both elevating rods 9 are always urged upward, and when the rods 9 are lowered, they are lifted by the pushing force of the spring.

The elevating rods 9a and 9b are always moved up and down at the same time, the upper end thereof projects above the casing 13, the lower part thereof is inserted into the casing 13, and an adjusting knob 25 integrated with an adjusting screw 23 screwed into the central portion thereof is provided. The sleeve-shaped stopper 27, which is adjusted up and down by the above, hits the bottom surface of the up-and-down block 22, and the lower limit positions of the up-and-down block 22 and the rod 9 are adjusted and regulated. Further, the upper limit position of the lifting block 22 is an O-ring 29 provided in the lower part of the bearing 15 in the upper part of the casing 13.
The spring receiver 19 is brought into contact with and is determined.

An upper base 33 is fastened and fixed on the elevating block 22 by a fixing bolt 31 which is inserted from below, and two front and rear guide rods 35 (35a, 35b) are vertically fixed in parallel on the upper base 33. A top plate 37 corresponding to the upper base 33 is fixed to the upper end of the guide rod 35.

Two clips 41, 43 are attached to a guide rod 35a in front of the guide rod 35 so as to be vertically movable via a bearing 39 such as a bearing or a bush. The clips 41, 43 have almost the same structure except for the shape of the grips 45a, 45b of the optical cord or ferrule attached to the tip, so that the same parts will be denoted by the same reference signs below,
The structure of the lower ferrule gripping clip 41 will be mainly described.

As shown in FIGS. 1 and 2, the clip 41 is vertically fitted and fixed horizontally to the bearing 39 with a certain interval, and its rear end is fitted to the rear guide rod 35b so as to be able to move up and down. Between the upper and lower plates 47, 49, a pair of clip levers 5
1, 51 are rotatably supported separately by shafts 53, 53, and gears 55, 55 meshing with each other between the plates 47, 49 are integrated with the shafts 53, 53 and levers 51, 51. It is provided by being axially supported.

As a result, the levers 51, 51 always operate symmetrically, and the grip 4
The centers of 5a and 45b are always kept constant. Further, sleeve-shaped spacers 57a and 57b are fitted to the tips of the plates 47 and 49, and the spacers 57a and 57b are the guide rods 35a and 3b.
The adjuster bolt 59, which is parallel to 5b, is vertically inserted. The upper end of the adjuster bolt 59 has a flange-shaped spring receiver 61a at the lower end and has a sleeve-shaped tension lock 61.
The tension lock 61 is screwed in and inserted, and the tension lock 61 is fitted on the tip of the top plate 37 so as to be able to move up and down.

Further, a sleeve-like tension adjuster 63 is fitted to the upper end of the tension lock 61 protruding above the top plate 37, and the tension adjuster 63 is
The lower end of the adjuster bolt 59 is in contact with the upper surface of the top plate 37, and the upper end of the adjuster bolt 59 is screwed through the upper part thereof. Then, the coil spring 65 that is mounted on the top plate 37 and the tension lock 61 is inserted, and the tension lock 61 moves up and down together with the adjuster bolt 59 by turning the tension adjuster 63, and thereby the downward pressing force of the spring 65 is adjusted. It is structured to be.

On the upper surface of the clip 41, a clip adjusting ring 67 that is inserted into the adjuster bolt 59 and a ring stopper 69 that is a nut screwed into the adjuster bolt 59 are provided, and also protrudes above the tip of the lower base 33. As described above, a clip stopper 71 made of a bolt is screwed in so as to be adjustable. Further, a pin-shaped spring hook 73 is projectingly provided on the tip of the upper clip 43. As shown in FIGS. 1 and 3, two hairpin-shaped pressing rods 75a, 75a and one end thereof are connected to a ring at a connecting portion. The coil portion 75b of the engaging spring 75, which has bent-shaped coil portions 75b and has bent portions 75c and 75c such that the other ends thereof intersect and face each other, is fitted to the spring hook 73. Has been done.

On the other hand, on both sides of the peripheral wall of the spacer 57b projecting above the upper plate 49 of the upper clip 43, there are provided slits 77 into which the pressing rods 75a, 75a of the engaging springs 75 are constantly inserted by the action of the inward force, The pressing rods 75a, 75a are pressed against the adjuster bolt 59 with a certain elastic force, and the clip 43 is supported by the adjuster bolt 59 by the frictional force of this pressing contact. When force is applied, the clip 43 moves up and down. Similarly, bend from both sides
When the pressing rods 75a, 75a are spread by pushing 75c, 75c and the pressing force on the adjuster bolt 59 is released, the clip 43 can move up and down freely.

On the opposing surfaces near the rear ends of the clip levers 51, 51, always spread the rear ends of the clip levers 51, 51 (that is,
A spring that urges the grips 45a or 45b to close)
79 is inserted and the clip lever is pushed against this spring 79.
51, 51 when pressed to the inside of the rear end, the grip 45a at the tip or
When 45b is opened and opened, it is closed by the bias of the spring 79.

The grips 45a or 45b of the clips 41 and 43 are always on the same axis, and the grips 45a and 45b of the clips 41 and 43 respectively grip the ferrule 83 and the optical cord 81 coaxially, and these A melting solder bath 3 is located below the shaft center.

That is, a core chip 87 connected to the tip of a horn 85 having an ultrasonic transducer (not shown) connected to the bottom thereof is accommodated upward in the solder bath 3, and a solder pot with a heating device is provided around the core chip 87. 89 is exterior and solder pot
In 89, Sn, Pb, Zn, glass obtained by adding a rare earth element thereto, or melting solder 91 having excellent adhesiveness to ceramics is accommodated. At the center of the upper end of the core chip 87, a relief portion 93 formed of a hole having a small diameter of about 1 mm is bored, and the center of the relief portion 93 is located on the downward extension of the axes of the grip portions 45a and 45b.

The ferrule 83 forms a main part to be inserted into the inside of the optical connector, and in the illustrated example, as shown in FIG. 8, a positioning flange 83b is projectingly provided on the upper outer periphery of the sleeve-shaped main body 83a. An optical code insertion hole 83c penetrates through the inner center, and a step portion 83d is formed at the lower end of the insertion hole 83c,
A sleeve-shaped capillary 83e made of ceramics or the like is fitted and fixed therein. An optical fiber insertion hole 83f of about 125 μm is formed in the center of the capillary 83e.
There is also a type in which the capillary 83e is not provided and the optical code insertion hole 83c is continuous with the fiber insertion hole 83f.

An optical fiber 81a, which fits with the fiber insertion hole 83f with a tolerance of about 1 μm, is accommodated in the inner center of the optical cord 81 with a silicone coat 81b, and the outer periphery of the optical fiber 81a is covered with a resin such as nylon 81c. Has been done. An optical fiber 81a protrudes from the tip of the optical cord 81 inserted into and fixed to the ferrule 83 by a length equal to or 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 ultrasonic waves are applied. 10 to 100 KHz depending on oscillator
Vertical vibration is inserted into the melting solder 91 in the solder pot 89 provided through the core chip 87, and solder is attached to the inner peripheral surface of the fiber insertion hole 83f and the outer periphery of the optical fiber 81a to form a preliminary solder coat. To do. These preliminary solder coats can be performed by any method, but when the ferrule 83 is dipped in the melted solder 91, the tip peripheral surface of the ferrule 83 is covered with a heat-resistant resin tube 95 (even if it is a shrinkable tube), It is desirable to protect the peripheral surface of the processed ferrule.

After the completion of the preliminary solder coat, the upper end of the ferrule 83 and the optical cord 81 are concentrically gripped by the gripping portions 45a and 45b at the tip of the clip. At this time, the optical fiber 81a is the ferrule 83.
It is not inserted inside. Next, the elevating block 22 is lowered to insert the tip of the ferrule 83 into the solder pot 89 under the application of ultrasonic vibration and bring it into contact with the center of the core chip 87.

In this process, the preliminary solder in the fiber insertion hole 83f of the ferrule 83 has melted, so the engaging spring on the clip 43
The bent portion 75c of 75 is pressed from both sides to release the pressing rod 75a from the adjuster bolt 59, and the tip of the optical cord 81 is inserted 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 along with the insertion, and by the ultrasonic vibration applied to the ferrule 83, the optical fiber 81a is formed at the center of the entrance of the fiber insertion hole formed in a mortar shape. As a result of the tip being guided, the optical fiber 81a is smoothly inserted into the fiber insertion hole 83f,
The tip of the optical fiber 81a is housed in the escape portion 93.

When the optical fiber 81a is inserted into the fiber insertion hole 83f, the engaging spring 75 is pushed and released from the open state, and at that position, the clip 43 is gradually moved to the fixed position of the adjuster bolt 59 while the clip 43 is fixed to the fixed position of the adjuster bolt 59. Fixed to. At this time, when the ring stopper 69 is adjusted to provide a constant gap with the upper surface of the clip 41 and the minute stroke of the elevating block 22 is repeatedly performed, melting solder is generated between the optical fiber 81a and the fiber insertion hole 85f. The melted solder penetrates uniformly by ultrasonic vibration into the gap between the two.

Finally, the ferrule 83 is brought into contact with the core chip 87, and the lifting block 22 is strongly pressed downward.
Ultrasonic soldering of the ferrule 83 and the ferrule 83 is performed, but at this time, the upper clip 43b also protrudes above the spacer 57b.
At the bottom of the tension lock 61,
The optical cord 81 is abutted while being biased by the spring 65 adjusted by 63, 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 by the above, the molten solder is pushed up into the minute gap (for example, about 1 μm) between them by ultrasonic vibration and soldering is performed, and the lifting block 22 is raised. By doing so, the solder will solidify in 2-3 seconds, so after the rise, the clip
Remove the optical cord 81 and ferrule 83 by 41, 43,
The resin tube 95 is removed and sent to the next processing step.

At the time of soldering, in order to prevent melting of the resin coating portion 81c due to heat of melting solder transmitted to the ferrule 83,
It is desirable to select a material for the grip portion 45a at the tip of the clip 41 as a material having a good heat output conductivity (that is, a high heat dissipation effect).

In addition, by performing either one of the preliminary solder coat of the fiber insertion hole 83f and the optical fiber 81a, it is possible to obtain a sufficient effect of performing soldering uniformly and with high strength in a short time.

Next, the second soldering method for fixing the optical cord 81 and the ferrule 83 will be described with reference to FIG. 7. In the same figure, a jet hole 97a of about 1 mm is formed in the center of the upper end surface of the core chip 87 in the solder pot 89. The jet nozzles 97 penetrating are placed concentrically and in contact with each other such that the contact surfaces with the upper surface of the core chip 87 are fitted to each other, and the jet nozzles 97 are fitted so as to hold a fixed position on the core chip 87. A jet-type soldering device in which the nozzle guide 99 is installed on the inner peripheral wall of the solder pot is used.

In this apparatus, when ultrasonic vibration is applied to the core tip 87, solder enters from the contact surface between the core tip 87 and the jet nozzle 97, and the melted solder 91 jets to the upper end surface of the nozzle 97 through the jet hole 97a. Soldering is performed by pressing the ferrule 83 with the preliminary solder coat and the optical cord 81 onto the upper surface of the jet nozzle 97 protruding 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 97 from which the melted solder 91 is jetting in the manner shown in FIG. 6, the end of the optical fiber 81a protruding from the tip of the ferrule 83 is pressed. The portion is accommodated in the jet hole 97a, and 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 is soldered while melting the preliminary solder coat.

According to this method, melted solder does not adhere to the peripheral surface of the ferrule 83, and it is not necessary to coat the resin tube on the tip of the ferrule or remove the adhered solder on the peripheral surface as in the case shown in FIG. It does not occur, and the heat from the melted solder is less likely to affect the ferrule and the optical cord. Also, the spare solder coat for the ferrule 83 and the optical cord 81 should be pressed against the end face of the ferrule 83, or
This can be performed by inserting 81a into the solder pot 89 or the jet hole 97a.

Even in the second method, the ferrule 83 and / or the optical fiber 81a are sufficient as the spare solder coat, or only one of them is sufficient.

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

A preferred mode of the method for performing the preliminary solder coating on the fiber insertion hole 83f of the ferrule will be described with reference to FIGS. 9 and 10.

The sensor 100 for detecting the completion of the preliminary solder coat is inserted into the optical code insertion hole 83c of the ferrule 83 from above.
This sensor is provided with a stopper 101, and the tip of the sensor is positioned at the upper end of the optical fiber insertion hole 83f when the stopper contacts the upper end of the ferrule. Next, this ferrule is gripped by the gripping portion, descends, and contacts the upper end surface of the jet nozzle 97. Melting solder 91 is jetted from the jet hole 97a to the upper end surface of the jet nozzle by ultrasonic vibration.By contact between the lower end surface of the ferrule and the jet nozzle, this melting solder enters the fiber insertion hole 83f of the ferrule and pre-solder. The coat is done. When the molten solder reaches the upper end of the fiber insertion hole 83f, the sensor 100
Then, the conduction of the solder pot 89 is detected, the application of ultrasonic vibration is automatically stopped, and the preliminary solder coat is completed. In this sensor, a heat-resistant absolute layer 103 is provided on the outer peripheral surface of a copper wire 102, and its tip is slightly exposed. The insulating layer is preferably made of a material such as polyimide resin, silicon resin, and fluororesin, which has heat resistance that does not deteriorate at working temperature and has insulating property at the working temperature. The sensor is not limited to this. For example, conduction with molten solder in the solder pot 89 may be detected, and two conductive wires insulated from each other are exposed at the tips, and the molten solder is attached to the exposed portion. Therefore, conduction can be detected.

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

When the completion of the preliminary solder coat in the fiber insertion hole is detected by the sensor as described above, a soldering defect due to a shortage of the preliminary solder coat is eliminated and a stable work can be performed easily, which is particularly preferable.

[Effects of the Invention] As a result of being configured as described above, the present invention has the following effects.

(1) The small diameter (12
Since an optical fiber (about 5 μm) can be passed to the required deepest part, the tip of the fiber does not come into contact with the vicinity of the fiber insertion hole inlet or the core tip or jet nozzle to prevent insertion, damage, deformation, etc. It is guided and inserted in a short time.

(2) When the ferrule tip is pressed against the core tip or jet nozzle with the optical fiber inserted and projected at the tip, the protruding end of the optical fiber is housed in the escape portion or jet hole, so The fiber insertion hole can be surely and smoothly dipped into the melting solder portion while being sufficiently inserted, the optical fiber can be reliably soldered in the fiber insertion hole, and the adverse effect of ultrasonic waves on the optical fiber can be reduced.

(3) The temperature rise of the ferrule, especially the upper end of the ferrule is small due to the shortened soldering work, and the resin coating of the optical cord is melted by heat (Note: 120 ° C to 1 ° C for nylon coating etc.
Problems such as (30 ° C. is the melting point) are reduced, and solder having a high melting point can be used.

(4) If the optical fiber through hole is melted and soldered, the preliminary solder coat melts faster than the new solder penetrates into the minute gap inside the through hole when soldering. This has the advantage that the soldering speed is increased and the soldering work is shortened as a whole. In addition, when applying the preliminary solder coat of the fiber insertion hole, if the completion of the preliminary solder coat is detected by the sensor and the application of ultrasonic vibration is stopped, soldering defects will disappear,
This is particularly preferable because stable work can be performed easily.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of an essential part showing an embodiment of an ultrasonic soldering device, FIG. 2 is a half cross-sectional plan view showing a clip structure, and FIG. 3 is a structure of an engaging spring above another clip. 4 to 7 are enlarged cross-sectional views showing a soldering method, FIG. 8 is an enlarged cross-sectional view showing a structural example of an optical cord and a ferrule fixed to each other, and FIG. FIG. 10 is an enlarged sectional view of an apparatus for applying a preliminary solder coat to the insertion hole of the fiber, and FIG. 10 is an enlarged sectional view of the sensor. 1: Main body table, 3: Melting solder bath 5: Connector holding device, 7: Rotating table 9 (9a, 9b): Lifting rod, 13: Casing 15: Bearing, 16: Lower casing 19: Spring bearing, 21: Coil spring 22 : Lifting block, 23: Lifting screw 25: Adjusting knob, 27: Stopper 29: O-ring, 31: Fixing bolt 33: Upper base 35 (35a, 35b): Guide rod 37: Top plate, 39: Bearing 41, 43: Clip, 45a, 45b: Grip 47,49: Plate, 51: Clip lever 53: Shaft, 55: Gear 57a, 57b: Spacer 59: Adjuster bolt 61: Tension lock, 61a: Spring bearing 63: Tension adjuster 65: Spring , 67: Ring 69: Ring stopper 71: Clip stopper, 73: Spring hook 75: Engagement spring, 75a: Push rod 75b: Coil part, 75c bent part 77: Slit, 79: Spring 81: Optical code, 81a: Optical fiber 81b: Silicone coat, 81c: Cover part 83: Ferrule, 83a: Main body 83b: Fragment , 83c: Optical code insertion hole 83d: Step portion, 83e: Capillary 83f: Fiber insertion hole, 85: Horn 87: Core chip, 89: Solder pot 91: Melting solder, 93: Escape portion 95: Heat-resistant resin tube 97: Jet nozzle, 97a: Jet hole 99: Nozzle guide 100: Sensor

Claims (3)

(57) [Claims] 1. A ferrule (83) is obtained by accommodating a core chip (87) which vibrates ultrasonically in a solder pot (89) which accommodates the melting solder (91), and which is melted by the ultrasonic vibration (91). ) And the optical fiber (81a) inserted in the optical fiber insertion hole (83f) of the ferrule (83) are soldered, the core chip (87) is a relief having a hole of a predetermined depth at the tip. The part provided with the part (93) is used, and the melting solder (9
1) is present, and the lower end of the ferrule (83) is pressed against the core chip (87) so that the optical fiber insertion hole (83f) faces the relief portion (93), and the inside of the optical fiber insertion hole (83f) Optical fiber (81a) and ferrule (8
3) Soldering method of optical connector to solder. 2. A ferrule (83) is housed in a solder pot (89) containing a melting solder (91), a core chip (87) vibrating ultrasonically, and the melting solder (91) to which the ultrasonic vibration is applied. ) And the optical fiber (81a) inserted in the optical fiber insertion hole (83f) of the ferrule (83) in a soldering method, the core side of the core chip (87) has a melting solder ( A jet nozzle (97) penetrating a jet hole (97a) that guides and jets a fluid (91) is placed in contact with the fiber, and a fiber insertion hole (83) is placed on the jet hole (97a).
f) The ferrule (83) is pressed against the jet nozzle (97) so that they face each other, and the optical fiber (81a) and the ferrule (83) are soldered inside the fiber insertion hole (83f). Attaching method. 3. An optical fiber insertion hole (83f) having a preliminary solder coat applied by ultrasonic vibration is used as the ferrule (83), and the sensor (100) is used for the optical fiber insertion hole during the preliminary solder coat. The soldering method according to claim 1 or 2, wherein the completion of the preliminary solder coat in (83f) is detected and the application of ultrasonic vibration is stopped.