JPS59181305A - Manufacture of flexible optical fiber bundle having reinforced end part - Google Patents

Abstract

PURPOSE:To bend at an acute angle in the tip part by packing an optical hardening plastic having flexibility in the vicinity of the boundary of a sticking part and a flexible part, irradiating light to a necessary part of this packed part, and hardening only the limited part. CONSTITUTION:A lot of optical fibers 32 are stuck as one body in an end part 38 by an acid-soluble glass 38a. An optical hardening plastic 33a having flexibility is filled in a boundary part of the end part 38 and a flexible part 39, and other part than the boundary part 40 of the end part and the flexible part is covered with a light shielding member 35. Subsequently, the filled plastic 33a of the boundary part 40 is hardened by irradiating an ultraviolet ray by a light source 37. In this way, the outside circumference of the boundary part to which the largest stress is applied in case of bending is reinforced, and also sufficient flexibility can be provided to the tip part.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a flexible optical fiber bundle. More specifically, each optical fiber is fixed in part,
The present invention also relates to a method for manufacturing an optical fiber bundle in which other parts have a property of being flexible.

Currently, optical fiber bundles are used for image guides, light guides, etc., but when used as an image guide, it is necessary to match each fiber one-to-one at both ends to obtain a clear and correct image. It is necessary to arrange them correctly.

Particularly when the optical fiber bundle for image guide is used as a bell, etc., it should be flexible except for the ends so that it can be inserted for observation at any point in a hollow body such as a body cavity or a device. It is necessary for the tip to be able to bend freely and at a steep angle.

By the way, various methods have been proposed for producing optical fiber bundles that are flexible except for such end portions, and whose leading portions can be bent freely and at a steep angle.

For example, a core glass with a high refractive index is placed in the inner crucible of a double crucible, and a covering glass with a low refractive index is placed in the outer crucible.
The two-hole crucible is heated to an appropriate temperature, both glasses are pulled through the bottom hole of the crucible, the core glass is covered with the covering glass, and the obtained optical fiber is wound in a row of loops without gaps. Fix it in one place with adhesive, wrap it in a loop shape in a line without any gaps as before, fix it with adhesive at the fixed part of the loop formed earlier, and repeat this operation to get the desired thickness. A loop-shaped optical fiber bundle is obtained, the flexibility is obtained by cutting approximately the center of the fixed part of the loop-shaped optical fiber bundle at right angles to the length of the optical fiber, and polishing the two cut surfaces. A method of manufacturing an optical fiber bundle for an image guide is known. At this method pressure, in order to make an optical fiber of a desired thickness (for example, 20μ) by heating i[gl]
The subsequent manufacturing process, that is, the arrangement of the optical fibers, requires great skill as the optical fibers are extremely thin, and the risk of cutting is high, so the yield rate of the image guide using this method is low. However, it also has the disadvantage of being expensive. As another method, a method for producing optical fiber bundles by acid elution is known. That is, in this method, a core glass with a high refractive index is placed in the innermost crucible of a triple crucible, a coating glass with a low refractive index is placed in the outer crucible, and an acid-soluble glass is placed in the outermost crucible. The entire crucible is heated to an appropriate temperature, and ti is poured from the bottom hole of the crucible.
A triple optical fiber (the diameter of this 3Y; Pf-fiber is about 200 fibers) is made by drawing the various glasses listed in TL, covering the core glass with a coating glass, and further covering the outer periphery with acid-soluble glass. The triple optical fiber is made into a suitable length of about 400 m.
m) and cut a large number of them (for example, 10,000 pieces)
The optical fibers are bundled, melted, heated to an appropriate temperature, and stretched until the diameter of the optical fibers becomes about 1/15. Both ends of the thus obtained hard optical fiber bundle are coated, and then the optical fibers are It consists of contacting the entire bundle with an acid (eg nitric acid) to elute the acid I-soluble glass from the intermediate portion of the optical fiber. Compared to the above method, this method requires approximately 2 times more optical fiber alignment work.
Since the work can be done with a thick piece of about 00μ, the arrangement is easy and there is very little risk of cutting. Moreover, after the arrangement, the upper Nr2 is completely eliminated because they are integrated by heat fusion. Therefore, according to this method, the production yield is higher than that of the above-mentioned method, and the cost can be significantly reduced.

Is this effect caused by optical fiber? I41+ <If it becomes #, it will become bigger. However, in this method, each fiber at the end of the optical fiber bundle is very firmly fixed by the acid-soluble glass, making it easy to break.

To address this drawback, it has been proposed to fill the vicinity of the boundary with plastic having appropriate hardness and flexibility for reinforcement. However, when filling a liquid plastic with a low viscosity, the liquid plastic permeates into the center of the boundary and at the same time flows out in the longitudinal direction, increasing the length of the boundary between the end and the bending part, and the tip of the optical fiber bundle. It becomes difficult to bend the part at a sharp angle.

To address the above drawbacks, we heated the edges, cooled the 1m part near the boundary, and infiltrated and hardened the liquid glass, which becomes harder after assimilation, at the boundary between the southern part and the 61st bending part to reduce the dimensions of the boundary as much as possible. A method for reinforcing the end of an optical fiber bundle so that it can be made shorter (Japanese Patent Publication No. 57-20603), in which a semi-dissolved part existing between a fixed part and a flexible part is filled with a polymer soluble in a organic solvent. After infiltrating and curing the molecular substance, this semi-dissolved part is firmly fixed from the outer periphery, and then the organic solvent is used to dissolve and remove the polymeric substance adhered to the area outside the semi-dissolved part μ, and the boundary part is removed. I tried to get the dimensions as short as possible) Y:
Science #AI! Method for strengthening the southern part of cord bundles
6- Publication), the fixed part is heated, the flexible part is cooled, and a thermosetting reinforcing agent is infiltrated from the outer periphery of the semi-dissolved part that exists between the fixed part and the flexible part, thereby reinforcing the semi-dissolved part. After curing the agent,
A method for reinforcing the southern part of an optical fiber bundle (Japanese Unexamined Patent Publication No. 51-68840-41) has been proposed in which the uncured reinforcing agent is removed and the dimensions of the boundary portion are made as small as possible.

However, these prior art Fi have various drawbacks as described below. It is disclosed in Japanese Patent Publication No. 57-20603 and Japanese Patent Publication No. 51-68840 the other day, in which the fixed part is heated, the 5T flexible part is cooled, and the boundary between the fixed part and the flexible part is penetrated. However, the temperature distribution at the boundary has a certain slope, and the required 11i
It is difficult to sharply limit only the 'j' area, and it is important to shorten the boundary area to a desired size or less. It also requires a relatively long time (for example, several hours) to cure. Tokuko Sho 5
6-42846 (disclosed in Japanese Patent Publication No. 6-42846), a plastic V is applied to the boundary between the fixed part and the flexible part in the academic string bundle.
After passing through and curing, it is necessary to cover the outer periphery of the boundary with a IIJ flexible tube, wrap a metal wire tightly around the outer periphery, and glue the metal wires together or weld the l'', which increases the number of parts. , the number of machining steps increases, and the diameter becomes higher.Also, the outer periphery of the boundary part of the tip is covered with a flexible tube, and the metal wire is tightly wrapped around the outer periphery, so the tip becomes longer and the diameter becomes larger. It becomes difficult to bend the tip freely and at a steep angle.

The present invention has been made in order to eliminate the above-mentioned drawbacks, and its purpose is to distinguish between the fixed part and the flexible part. By filling the area near the field with a flexible original curable plastic and irradiating the necessary parts of this filling with light to harden only the limited parts, an optical fiber bundle that can be bent at a steep angle at the optical end ri+ can be efficiently produced. It is intended to provide a method of manufacturing.

That is, the present invention provides a flexible optical fiber bundle in which each optical fiber is fixed together with a soluble glass or a filament-based adhesive in the southern part.
Flexibility characterized by filling a flexible photocurable plastic between each optical fiber near the boundary with parts j and q, and curing by irradiating light onto the necessary parts of the filled part. Elephant of optical fiber bundle! It is related to the method of sending.

Next, typical embodiments of the present invention will be described in detail with reference to the drawings. First, in a triple crucible as shown in FIG.
and an acid-soluble borosilicate glass 7 are charged into the outermost crucible 10. Core glass #, t1 that can be used in the present invention has, for example, the following composition and properties.

Composition of core glass (air volume %); Sto: 45.
0%, K, 0: 11.0%, PbO: 24.0%
, BaO: 12.0%, ZnO: 5. OTo...
'A/103: 3-0%, Astol: 0.
7%, refractive index (Na): 1.59062, dislocation point:
528℃, softening point = 583℃, coefficient of thermal expansion: 99X
10-7~ra°C.

The coated glass that can be conveniently used in the present invention has, for example, the following composition and properties.

Composition of coated glass (heavy starvation %): SiOx: 64
．． 04% Nano: 16.0%, pbo
: 12. oc+, ZnO: 5.0%, A110
B: 3.0, Δl! tOs: 0.7%, refractive index (Nd): 1.52852, dislocation point: 486°C
, Softening point: 533℃, Thermal expansion coefficient: 98 x 1.0
-0-7r100°C.

The acid i-soluble glass that can be conveniently used in the present invention has, for example, the following composition and properties.

Composition (ff1%i:%): 5cot: 19.5
%, 8103: 36.5%, Nano: 11.0
%, BaO: 26.0%, ZnO: 7.0%, AI
, Os: , 0.3%, Refractor (Nd): 1.58090
．． Dislocation point: 540℃, softening point: 574℃, thermal expansion coefficient c1
．． : 92×1O-7crv'an°C.

Next, the triple crucible containing the core glass, coating glass, and acid-soluble glass is heated in the electric furnace 11 to form the triple optical fiber 13.
is pulled by roller 12. FIG. 1 shows a diametrical cross-sectional view of the triple optical fiber 13 obtained. 3 r<f iY:
The outer diameter of the academic fiber 1 is about 200μ, the thickness of the acid-soluble glass 4 is about 5μ, and the thickness of the coating lath 3 is about 20μ.

Next, cut this three-layer optical fiber 1 into approximately 400 lengths,
The end portions of each optical fiber were arranged in a line without any gaps so that the end portions corresponded to 1:45.1 to form 118 optical bundles (approximately 10,000 fibers), which were heated and melted.

Next, as shown in FIG. 3, the heated fiber bundle is further heated and drawn. That is, the optical fiber bundle 113 and the roller 14 that have been thermally fused are sent downward little by little, and the tip thereof is heated to about 700° C. in the electric furnace 16 to soften it, and then stretched downward by the roller 15. In this case, the diameter of the stretched optical fiber bundle 17 is 1/1 of that of the one when heated and fused.
5 degrees, or about 1.5 degrees. As a result, the diameter of each optical fiber is approximately 13μ.

Next, both southern parts of the obtained hard optical fiber bundle 17 are covered with an elution prevention coating 1k20, and the entire optical fiber bundle with both ends covered is placed in an elution treatment tank 21 as shown in FIG. and process it.

Elution treatment can be carried out, for example, by treating with IN nitric acid at about 70°C for about 2 hours and washing with water, or by washing with water after treating with nitric acid and then boiling at 0°C at about 35°C.
．． After treatment with 5N NaOH for about 1 hour, wash with water. Fifth
4 is a schematic diagram of the end portion 31 and the flexible portion 30 of the Yakusei cord bundle which has been given flexibility by the above-mentioned elution treatment. Figure 46 is a new view showing an example of the vicinity of the lower part of the bundle according to the present invention. 〃The boundary between the first part 38 and the flexible part 39 is filled with a flexible photocurable plastic 33, and the XHY; The filling plastic 33 in the boundary portion 40 is cured by irradiating ultraviolet rays (or sunlight) Y:) through the cover 37.

Furthermore, if necessary, Cemedine 156, which is a part of the epoxy resin, is added to strengthen the vicinity of the end 38 of the optical fiber bundle whose boundary part is filled with hardening plastic as described above.
5/D.

Alternatively, a flexible plastic such as Araldite AY103/)1Y956 may be placed in the base, and at the same time, at least a portion of the boundary portion may be covered with a flexible plastic. This makes it possible to strengthen the outer periphery of the boundary where the greatest stress is applied during bending, and at the same time to impart light flexibility to the tip.

Three cods with modified acrylic resin as original hardening plastic? The 3000 series manufactured by N.D. Co., Ltd. is preferable. When using photocurable plastics, Japanese Patent Publication No. 57-20603
As described in Japanese Patent Application Laid-Open No. 51-68840 (compared to the case where the plastic at the boundary is hardened by cooling the Hll end and heating the IN end, the positional density of the hardened part is considerably larger). It is possible to make the stiffening part very short and high, and it is possible to make a fairly steep angle M1 curve of the leading part.

Furthermore, in the case of photocurable glass, it cures in a very short time (for example, in seconds), so it has the advantage of automating the manufacturing process and making it easy to use nude materials. Figure 7 tityu part 3
8 and the flexible portion 39 have flexibility at the boundary! , ta(・Magsenryu sex to 11) Y: Light j fix the hardening furanutikku 33a, to the history ()・bow, - sex imparting type gen-classifying shira 7 tick 34 (□i;II eha The first part of the side and the boundary part are broken using Nuriebond's No. 3000 series, and the first step is to break the yfM part with #tRig3.
6 to block the air: :L This part (D harden the plastic 34. Next, as the second step, 3Lp 5
Y-, part @' 35 a and i+ +it /4 (,”
At '°36, the outside of the boundary 40 area is irradiated with ultraviolet rays (also C Mat 1-L>Light) by Marshal 37 and the boundary area 4θ
The inner coating 1, the "reglass deck 34," is cured. In this case, the outer periphery of the boundary part can be reinforced and at the same time the end of the optical fiber bundle can be reinforced and made thinner.

%ii] - 1lit' of the second step (It goes without saying that the order may be reversed.

FIG. 8 is almost the same as the embodiment shown in FIG.
It decreases continuously toward the J-retaining part, increasing the mechanical strength near the end part 38 (;A part 11111), which reduces twisting and enables sharp bending of the original part. .Ibe 38 of the optical fiber bundle having senryu properties of this embodiment as required.
Cemedine 1565/D and H to strengthen nearby areas
At the same time, at least a part of the boundary part may be made of the above-mentioned flexible plastic (p, j 4%j) while fitting into the mouth via a plastic having senryu properties such as Araldite AY103/HY956.

In this embodiment, the filled plastic is intermittently cured, but the coating plastic may be partially cured by using a photochromic plastic or an anaerobically curable plastic. Alternatively, a photocurable plastic or an anaerobic curable plastic may be used for both filling and coating, and curing may be carried out continuously.

Figure 9 shows that the boundary between the rust 11 part 38 and the flexible part 39 is filled with d [flexible anaerobic type plastic Y] curable plastic 33e, and the damaged part 38 is further covered with the above plastic. FIG. 1 is a side view showing pL Gakutoku J fiber cord bundle R'A part attaching part-1 (1) according to the present invention, in which the peak part is first reinforced and fitted into the gib 36 as a first step. to harden the plastic 34a corresponding to the VJB.Next, in the second step, the gU light member 35c and the sleeve!iUi pipe 36 are
Then cover the area other than the boundary part 40 and harden the filling plastic 33c in the boundary part 40 by irradiating ultraviolet rays (or sunlight) from the edge 37Vc! 7ru. In this case, the boundary part can be filled with plastic and hardened in a short time, and at the same time, the end of the 1tC-original string bundle can be coated with an acid layer on the reinforcing piezo. You can also reverse the IiM order of the first and second steps above:
[It goes without saying.

FIG. 10 further shows an embodiment of the mouth:;μ, in which 5% 6. IHI port 5G with a predetermined width at [14j] with a certain boundary part 40
4 is provided. By providing such a light flux limiting member 50, there is no need to attach a light shielding member 35 as shown in FIG. Furthermore, by making the opening I] 50a of the nine-bundle-limited f$ material 50 variable, it is possible to perform photo-curing work on a portion according to the purpose. In addition, instead of the limiter 50, a cylindrical lens or the like may be used to form a band-shaped light beam of a predetermined width, or the irradiation range may be limited by using a combination of mirrors, lenses, etc. It is.

In the above-mentioned embodiments, the boundary between the end fixed with wire M glass and the iiJ bending part was described as deli.
p1! Even when the eyebrows are fixed, they can be strengthened in the same way.

As described above, the present invention is made of hardenable plastic with elasticity and anaerobic property attached near the boundary between the M part and the flexible part. Type) 't, hardening gractic, part 1; I
Use one of the L plastics to show off the outer periphery of L6 to the private on y4 with one of the L plastics. Requires feed r9[to be irradiated with light or to block the air 1; iiJ flexible optics with hardening and hardening in the southern part
〃It provides a method for efficiently manufacturing Shi Usuzuka. According to the present invention, the position of the serpentine part of the plastic can be precisely determined, and the reinforcement part near the sheath can be made sufficiently small, so that there is no need for sharp bending of the tip part. This is extremely convenient for people like Ji Wei. In addition, the curing time is very fast, for example on the order of seconds, which speeds up the process of making culms. J becomes 6 easy.

In the :;'f: /lLQ example of the present invention, Cemedine 1565, which is a family of epoxy resins, is used as a glass material having Ii characteristics. /I), Aralgate AY103/
Although 1lY956 has been described, other flexible plastics may be used. In addition, a pressure mercury lamp or the like is preferable as a source for ultraviolet rays.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the 3 i1N optical fiber. Figure 2 is a schematic diagram of the process of heating the Mikawa crucible and drawing the optical fiber. Figure 4 is a schematic diagram of the process of elution treatment of acid-soluble lath. Figure 5 is an optical gradient I-string with the inner end glued with acid-soluble glass and the middle part with an opening. A schematic diagram of a bundle. Figure 6 shows 1, 13...3 electric fibers with 114 properties to which this developed ll!J is applied 2.5... core glass 3.6... coated glass 4.7.38a... Acid-soluble glass 8.9.10... Crucible 11.16... 1 Air furnace 12
．． 14.15...Roller 17...Optical (!?) fiber string bundle 8...Heat-fused optical lρ, fiber bundle string...Treatment liquid 20...Elution prevention covering 21 ... Processing tank 30 ... Flexible former Gakunaka cord bundle town burning section 31 ...
・End part 32 of optical fiber bundle with wanderability...Double optical fiber 33.33m, 33b, 33cm filled plastic 34
．． 34a...Coated glass 35.35m, 35b = State party member 36...Reinforcement) e Eve 37...″#: Source 38・
...End part 39...Choice part 40...Boundary part between iJ ridge part and end part JC 9 Fig. 6 Fig. 1O

Claims (1)

[Claims] (11) A method for obtaining a flexible optical fiber bundle in which a plurality of optical fibers are integrally fixed at their ends, and the other parts are separated and flexible parts. Step 1 and J
: In a method for manufacturing a flexible end-strengthened string bundle comprising a second step of reinforcing the vicinity of the boundary between the fixed part and the flexible part, the second step comprises the steps of 5] Adding a flexible photocurable plastic near the boundary, and after that step L
1. A method for producing a flexible optical string bundle with reinforced ends, comprising the step of irradiating light onto a predetermined position of an applied part of a hardening plastic and curing it. (2+ The process of applying the above-mentioned ridge-forming plastic, stick, etc. is carried out in the vicinity of the above-mentioned boundary.) Also, the coating on the outer periphery of the optical fiber bundle is filled between the q+ fibers of the optical fiber bundle. 2. A method for producing a flexible optical fiber bundle with reinforced end portions as set forth in claim 1. (3) The photocurable plastic is made of anaerobically imparted Taigu and is a flexible optical fiber bundle with reinforced end portions as set forth in claim 1 or 2. manufacturing method. (4) The light irradiation step (5) is characterized in that the light irradiation step is performed through means for limiting the irradiation range to a predetermined position near the boundary (G). A method for producing a flexible optical fiber bundle with reinforced ends as described above.