JP3390709B2 - Cleaning apparatus and method for cleaning optical fiber bundle - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning device and a method for cleaning an optical fiber bundle using the cleaning device, and more particularly, to an optical fiber bundle having a uniform arrangement which is fused and integrated without voids and then heated and stretched. Accordingly, the present invention relates to a cleaning device and a cleaning method for a fiber bundle, which are useful in the process of manufacturing an image transmission body.

[0002]

2. Description of the Related Art In the case of constructing an image transmission body by bundling a large number of optical fibers with the arrangement phases at both ends aligned,
The image resolution depends on the diameter of the optical fiber. In order to increase this resolution and obtain a sufficient image area, it is necessary to accurately arrange a large number of extremely thin fibers, but the diameter is 10 μm.
Fabrication is extremely difficult by a method of directly arranging fibers around m or less, and therefore, the heat drawing method is widely used.

In this heating and drawing method, first, an optical fiber element wire having a diameter (for example, about 200 to 300 μm) that is relatively easy to handle is formed, and a large number (for example, thousands to tens of thousands) of this element wire is formed into a glass tube. Close packing with the inside aligned in parallel. The inside of the glass tube is decompressed and the whole is heated and softened, and if necessary, a high pressure is applied from the outside of the glass tube to fuse the fibers by deformation due to the pressure difference between the inside and outside of the glass tube and at the same time crush the voids between the fibers. In this way, after manufacturing a large-diameter optical fiber bundle that is fused and integrated without gaps, the large-diameter optical fiber bundle is heated and drawn to obtain a small-diameter optical fiber bundle for image transmission having a desired pixel diameter. To produce.

The fiber bundle obtained by the above method is a rigid one in which the fibers forming the pixels are fused together.
By the method described below, a flexible image transmission body in which both ends are fused and integrated and individual fibers are separated in the middle part is also manufactured.

That is, as the above-mentioned optical fiber strands, a core glass having a high refractive index, a clad glass having a low refractive index surrounding the core glass, and an elution glass layer made of acid-soluble glass coating the outer periphery of the core glass. A fiber having a triple structure of is molded. After this wire is packed in a glass tube most closely, it is fused and integrated by heating and pressing as described above, and then the outer glass portion is removed by grinding or the like. Thereafter, the large diameter fused fiber bundle is heated and drawn to produce a small diameter rigid fiber bundle (conduit), and thereafter, both ends of the conduit are covered with an acid-resistant protective material to remove nitric acid. By contacting with an acid solution such as an aqueous solution, the dissolved glass fused between the fibers is dissolved and removed. As a result, a flexible image transmission body with extremely high flexibility is obtained in which the fibers are fixed at both ends in a state in which the arrangement phases are aligned and the fibers are separated from each other in the middle part.

As described above, in the method of manufacturing an optical fiber bundle including the heating and drawing step, the cleaning of the optical fiber strand has a great influence on the quality of the final product. That is, while the diameter of each fiber forming the fiber bundle is reduced by heating and stretching, when there is a foreign material having a higher softening point than glass between the fibers, it remains in the fiber bundle after being drawn with the same size. This abnormally deforms the surrounding optical fibers and blocks the light transmission, resulting in black spots or dark spots in the image and degrading the image quality.

Therefore, it is necessary to wash the strands well and to clean the outer surface as much as possible before heating and fusing the bundled strands. Conventionally, the optical fiber strands are in a separated state. Then, ultrasonic cleaning is carried out, and a predetermined tube is filled after cleaning.

[0008]

In the above-mentioned method, even if the fibers are sufficiently cleaned by ultrasonic cleaning, the foreign substances are re-adhered to the fiber surface during the long-time work of filling the tube in an array. Is likely to. Further, there is a problem that the glass powder generated from the fiber ends at the time of filling remains between the fibers as it is, which adversely affects the optical transmission characteristics of the fibers.

[0009]

A cleaning apparatus according to the present invention is provided with a cleaning liquid press-fitting pipe at one end of a cylindrical body made of a stainless steel pipe or the like, the inner diameter of which is highly uniform over the entire length and whose both ends are open. The side is provided with a cleaning unit to which discharge pipes are respectively connected via connecting tools. Further, an ultrasonic bath capable of immersing the entire cleaning unit in an ultrasonic transmission medium liquid such as water is provided, and an ultrasonic vibrator is mounted on the inner surface of the side wall thereof. In addition, a drive mechanism is provided for suspending the cleaning unit in the ultrasonic bath, lifting and lowering operations for immersion and removal, and swinging and rotating in the ultrasonic bath.

In the cylinder of the cleaning unit, a large number of optical fiber element wires are densely packed in parallel with each other. Prior to filling the cylindrical body, it is desirable to pre-clean the strands in a separated state in the same manner as in the conventional case.
After the above filling, a pipe for press-fitting the cleaning liquid is connected to one end of the fiber-filled cylinder, and a pipe for discharge is connected to the other end. Next, the fiber bundle-filled cylinder to which the cleaning liquid pipe is connected is immersed in the ultrasonic transmission medium liquid.

After the above-mentioned preparation, a clean cleaning liquid is caused to flow through the pipe into the cylindrical body, and ultrasonic vibration is applied to the cylindrical body through the liquid medium. When the cylinder is immersed in the ultrasonic wave transmitting liquid, it is set in a standing posture in the present invention. That is, the cleaning unit is placed in the liquid medium so that the axis of the optical fiber filled in the cylinder is substantially vertical, and ultrasonic waves are applied from the side surface of the cylinder.

(Operation) According to the above-mentioned method, the foreign matter attached to the fiber surface is released from the fiber surface by ultrasonic vibration and is carried away by the cleaning liquid flowing in the cylinder. Therefore, even if foreign matter is newly mixed between the fibers during the array filling operation into the tubular body, it is washed away in the above process, and since the fiber bundle is already in the parallel array state,
The fiber bundle that has been kept in a parallel state due to adsorption due to wetting extracted from the tubular body is put into the glass tube as it is, and then it is only necessary to fill a small amount of fiber in the gap between the inner circumference of the glass tube and the outer circumference of the fiber bundle. Therefore, foreign substances are almost never newly mixed between the fibers constituting the fiber bundle, and a highly clean interface can be maintained until heat fusion.

Further, due to the synergistic effect of the ultrasonic vibration and the laminar flow of the cleaning liquid that is press-fitted into the cylinder, there is also an effect that even if some alignment disorder is present in the fiber, it can be corrected. Furthermore, when applying ultrasonic vibration, the fiber-filled cylinder and the cleaning liquid piping connection part that follows both ends of this can be put into the liquid, and ultrasonic vibration can be applied through this liquid, so there is no need to leave it over the entire length of the fiber. Ultrasonic vibration can be given without.

However, when the above-described cleaning liquid press-fitting and ultrasonic vibration application are carried out in a state where the fiber-filled cylinder is placed horizontally (the fiber axis is horizontal), the foreign matter sandwiched between the fibers is above it. The weight of the fibers makes it difficult for them to move due to the inward force acting between the fibers, and even if foreign matter is released from the fiber surface, the There is a high possibility that the foreign matter will sink due to its own weight and will adhere and remain on the fiber surface again, but in this point the method of the present invention is in a standing posture and ultrasonic vibration is applied from the side. Retaining and re-adhesion hardly occur, and extremely effective cleaning can be performed in a short time.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described in detail with reference to the embodiments shown in the drawings.

FIG. 1 shows a cross section of a cleaning unit immersed in an ultrasonic bath. The cleaning unit 100 includes a cylindrical body 2 in which a large number of optical fiber strands 1 are densely packed in parallel in advance.
The cleaning liquid press-in pipe 5 and the outflow pipe 6 are connected to both ends of the pair of connecting plates 30 and 40 through a pair of holding plates 8A,
8B and the bolt 9 that fastens between these two holding plates,
It is assembled by clamping it from both ends. A pair of suspension holders 7A and 7B are fixed to the holding plate 8A on the cleaning liquid press-in side, and a holding portion for transportation is provided on the holding plate 8B on the outflow side.

More specifically, the connector 3 on the cleaning liquid press-fitting side.
Reference numeral 0 denotes a cap member 31 having a hole for receiving the end portion of the tubular body 2 and a ring screw member 32 fastened to a screw provided in the cap member 31, and the tubular body 2 filled with a fiber bundle. Fit the cap member 31 on the end of
By tightening the ring screw member 32 into the cap member 31 via the rubber ring 33, the rubber ring 33
Seals the gap to prevent leakage of cleaning liquid. A cleaning liquid pipe connection hole 31A is provided at the center of the cap member 31, and the cleaning liquid pipe 5 is connected thereto.

On the other hand, the connector 40 on the cleaning liquid outflow side includes an end cap member 41, an intermediate member 42, and a ring screw member 43.
Composed of and. Further, a stopper plate 44 for preventing the fibers from coming out is arranged in the space inside the connector 40 by sandwiching and fixing the peripheral edge thereof between the cap member 41 and the intermediate member 42. As shown in the front view of FIG. 2, the stopper plate 44 is provided with notches 44A at regular intervals on its peripheral edge. The stopper plate 44 prevents the fibers from flowing out of the cylindrical body 2 due to the pressure of the cleaning liquid, and the peripheral cutout 44A allows only the cleaning liquid to pass through.

The cap member 41, the intermediate member 42 and the ring screw member 43 are screw-coupled to each other, and a rubber ring is liquid-tightly sealed between them. In addition, the cap member 41
A cleaning liquid pipe connection hole 41A is provided at the center of the cleaning liquid pipe 6, and the cleaning liquid pipe 6 is connected to this hole.

However, when the pressure of the cleaning liquid is high to some extent, the outward force exerted on the connecting members 30, 40 by the internal liquid pressure causes the connecting members 30, 40 to move outward against the frictional force of the rubber ring. May move and fall out. In order to prevent this, after the above-mentioned piping connection, the holding plate 8A,
It is sandwiched by 8B, and the pressing plates 8A and 8B are fastened with an appropriate number of bolt members 9 to give an inward tightening force.
A slit 10 having an opening at the upper end is provided at the center of each of the pressing plates 8A and 8B, and a pipe connecting portion is dropped into the slit 10 so as to be easily set.

FIG. 3 shows a sectional view of the ultrasonic device. This apparatus 200 includes an ultrasonic bath 202 on a pedestal 201, an elevating drive mechanism for moving the cleaning unit 100 into and out of the bath 202 in a vertical posture, and a rotating mechanism for swinging and rotating the cleaning unit 100. It is assembled and configured. An ultrasonic transducer 204 is provided on each of opposite side walls of the ultrasonic tank 202.
Is attached. That is, the vibrating surface of the oscillator 204 is the tank 2
It forms part of the side wall of 02. The size of the ultrasonic transducer 204 is such that it can completely cover the entire length of the cleaning unit 100. The tank 202 is filled with water 203 as an ultrasonic transmission medium liquid.

The cleaning unit 100 is vertically suspended from a hook 205 having a gate shape via suspension holders 7A and 7B. The hook 205 is attached to the lifting platform 206 and the axis 20
The motor 209 is rotatably attached around 5A and is repeatedly rocked and rotated within a certain angle range by a motor 209 provided on the same frame. Due to this swinging rotation, ultrasonic waves generated from the surface of the ultrasonic transducer 204 are generated by the cleaning unit 1.
The entire circumference of the optical fiber bundle within the cylinder No. 00 is given evenly.

Therefore, in order to prevent dead spots, it is desirable to select the swinging angle range so as to oppose the vibrating surface of the vibrator 204 at least once in all circumferential portions of the side wall of the unit cylindrical body. However, the rotation in only one direction complicates the structure due to the presence of the cleaning liquid pipe, and also causes disorder in the arrangement of the optical fibers filled in the cleaning unit 100. Therefore, the method of the present invention repeatedly rocks. It is supposed to rotate. Generally, the swing angle is preferably in the range of more than 180 degrees and less than 360 degrees, and is set to 250 degrees as an example.

Since the fiber array is disturbed when rotated at an excessively high speed, a relatively gentle speed of about one rotation per minute is desirable. Further, it is not necessary to apply the ultrasonic wave for a long time, and according to experiments, a sufficient cleaning effect was obtained in about 15 to 20 minutes. On the other hand, it has been confirmed that it takes 60 minutes or more to obtain the same cleaning effect in the horizontal system. Further, if the intensity of the ultrasonic wave is too strong, the fiber arrangement is disturbed, so that an ultrasonic wave intensity of about 100 to 200 W (watt) is suitable.

In the apparatus shown in FIG. 3, the lift base 206 is vertically movable along the guide 208, and one end thereof is fixed to the cylinder rod 207A of the air cylinder 207 so that the air cylinder 207 can be expanded and contracted. To go up and down.

As for the order, first, the cleaning unit 100 is assembled outside the ultrasonic bath as described above, the cleaning liquid pipe is attached, and then the elevating stand 206 is vertically hung on the hook 205 at the elevated position, and the pipe 5, The cleaning liquid is passed through 6 to remove bubbles remaining in the unit cylinder. Then, the air cylinder 207 is operated, the pedestal 206 is lowered, the cleaning unit 100 is completely immersed in the water in the ultrasonic tank, and the hook 205 is oscillated and rotated by the drive of the motor 209, and ultrasonic waves are generated by the vibrator 204. Give vibration.

After the treatment for a certain period of time, the cylinder 20 again.
7 is operated to raise the pedestal 206, and the cleaning unit 100 is taken out of the ultrasonic bath 202. Meanwhile, the cleaning liquid continues to flow into the unit 100.

FIG. 4 shows a piping system for the cleaning liquid. Storage tank 30
1 stores a cleaning liquid 302, for example, ethyl alcohol, and the cleaning liquid 302 is pressurized by a pump 303 and sent into a pipe, and passes through a first filter 304A, a meter 305, and a pressure meter 306, and then a second filter 304A. It is filtered again by the filter 304B, flows into the cylindrical body 2 through the connection tool 30, flows between the fibers, and then enters the pipe through the connection tool 40 and is returned to the storage tank 301.

Here, the cleaning liquid filtering filter 304A,
It is desirable to use 304B that does not contain a surfactant. That is, when a filter material containing a surfactant is used, when a filter containing this surfactant is used, this surfactant dissolves into the cleaning liquid and adheres to the fiber surface, This is because the above-mentioned surfactant causes the fibers to stick to each other, which may cause the fiber to break. Examples of the filter material containing no surfactant include, for example, Millipore filter, product number WGFG-40.
H-01 is preferred.

As described above, the cleaning liquid 302 is placed in the cylindrical body 2.
The ultrasonic transducer 204 is activated while flowing the
Cavitation is generated in the medium liquid 203 inside, and thereby ultrasonic vibration is applied to the cylindrical body 2. As a result, the foreign matter adhering to the fiber surface falls off and is washed away with the cleaning liquid together with the foreign matter existing between the fibers. Further, since ultrasonic vibration is applied not only to the tubular body 2 portion but also to the pipe connecting members 30 and 40 portions on the extension thereof, a powerful cleaning action is fully provided over the entire fiber length.

In the figure, 307 is a one-touch joint, and the cleaning unit 100 is attached to and detached from the pipe at this joint 307, and the pipes 5 and 6 and the end cap members 31 and 41 described in FIG. It is used as it is while it is connected. Further, in FIG. 4, the cleaning unit 1
An example in which two 00s can be attached is shown.

The cleaning method of the present invention can be grasped from the forms shown in the following items.

3. The method for cleaning an optical fiber bundle according to claim 2, wherein ultrasonic vibration is also applied to the portion of the connector including the portion of the connector, which is immersed in the ultrasonic medium.

4. The optical fiber is composed of a high-refractive index core glass, a low-refractive index clad glass surrounding the core glass, and an elution glass made of acid-soluble glass surrounding the outer periphery of the clad glass. Item 2. The method for cleaning an optical fiber bundle according to item 2.

5. The method for cleaning an optical fiber bundle according to claim 2, wherein the cylindrical body is a stainless steel pipe having a uniform inner diameter over the entire length.

6. The method for cleaning an optical fiber bundle according to claim 2, wherein the cleaning liquid is alcohol.

7. On the cleaning liquid outflow side of the cylindrical body, in a connector for connecting the cleaning liquid pipe and the cylindrical body, facing the fiber bundle end surface, arrange a stopper plate provided with a gap to allow circulation of the cleaning liquid on the outer periphery, The method of cleaning an optical fiber bundle according to claim 2, wherein the stopper plate prevents the fibers from coming out of the cylindrical body due to the press-fitting of the cleaning liquid.

8. The method for cleaning an optical fiber bundle according to claim 2, wherein a filter containing no surfactant is used as the filtration filter for cleaning the cleaning liquid.

9. The method for cleaning an optical fiber bundle according to claim 2, wherein the cylindrical body is oscillated and rotated about its axis while ultrasonic vibration is being applied.

10. 10. The method for cleaning an optical fiber bundle according to the above item 9, wherein the angular range of the oscillating rotation is set so as to face any of the ultrasonic transducers at least once for all circumferential portions of the cylindrical side surface. .

11. 11. The optical fiber bundle as set forth in the preceding paragraph 10, wherein ultrasonic transducers are provided on a pair of opposing side walls of the liquid tank, and the oscillating rotation of the cylindrical body is performed within an angle range of more than 180 degrees and less than 360 degrees. It is a cleaning method.

12. 12. The optical fiber bundle cleaning method according to the above item 11, wherein the swing angle range of the cylindrical body is 250 degrees.

13. 10. The method for cleaning an optical fiber bundle according to the above item 9, wherein the rotation speed of the cylindrical body is one rotation per minute.

14. The method for cleaning an optical fiber bundle according to claim 2, wherein a time for applying ultrasonic vibration to the cylindrical body is within a range of 3 minutes to 10 minutes.

15. The optical fiber bundle cleaning method according to claim 2, wherein a flow direction of the cleaning liquid with respect to the cylindrical body is such that the cleaning liquid flows in from above and flows out from below.

[0046]

According to the present invention, when a large number of optical fibers are bundled in parallel and fused and stretched, they are attached to the fiber surface before the fusion in molding the image transmission body. Alternatively, the foreign substances existing between the fibers can be reliably removed over the entire length of the fibers. Further, since the cleaning is performed in a state of being bundled in parallel, the possibility that foreign matter will be mixed between the fibers in the working process of filling the glass tube with the fiber bundle is greatly reduced as compared with the conventional method.

[Brief description of drawings]

FIG. 1 is a half cross-sectional side view showing a cleaning unit immersed in an ultrasonic bath.

FIG. 2 is a front view of a stopper plate for preventing fibers from coming out.

FIG. 3 is a cross-sectional view of a main part of an ultrasonic device.

FIG. 4 is a piping system diagram of a cleaning liquid.

[Explanation of symbols]

1 Optical fiber strand 2 cylinders 5 Cleaning liquid press fitting pipe 6 Cleaning liquid outflow piping 8A, 8B Presser plate 9 Holding plate fastening bolt 30,40 connection 44 Fiber slip-out prevention stopper plate 100 cleaning unit 200 ultrasonic device 202 ultrasonic bath 203 Ultrasonic wave transmission medium 204 Ultrasonic transducer 205 swinging rotation hook 206 Elevating stand 207 Air cylinder 208 Lift guide 209 Hook rotation drive motor 301 cleaning liquid storage tank 302 cleaning solution 303 pump 304A, 304B Filtration filter 305 Meter 306 pressure gauge 307 Detachable joint

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Misao Shiraiwa 500 Murai Nishi, Iidaji, Kadota Town, Aizuwakamatsu City, Fukushima Prefecture (58) Fields investigated (Int.Cl. ⁷ , DB name) B08B 3 / 12 G02B 6/00 336

Claims (2)

(57) [Claims] 1. A cleaning unit in which a pipe for pressurizing a cleaning liquid is connected to one end of a cylindrical body whose both ends are open and a pipe for discharge of the cleaning liquid is connected to the other end through a connector, and the entire cleaning unit is immersed. An ultrasonic bath provided with an ultrasonic vibration source, and a drive mechanism for suspending the cleaning unit in the ultrasonic bath, performing an ascending / descending operation, and imparting swing rotation. A cleaning device equipped. 2. A cleaning liquid is provided on one end side of a cylindrical body whose both ends are open.
Of the press-fitting pipe and the discharge pipe on the other end side through the connecting tool.
A plurality of optical fibers are densely packed in a cylindrical body of the cleaning unit connected in parallel with each other, and the fiber bundle-filled cylindrical body to which the cleaning liquid pipe is connected is arranged so that the axis line of the fibers is substantially vertical. Immerse in the ultrasonic transmission medium liquid in the standing posture,
A method for cleaning an optical fiber bundle, characterized in that ultrasonic vibration is applied to the cylindrical body through the liquid medium while flowing a clean cleaning liquid through the pipe into the cylindrical body.