JPS58182603A - Optical fiber bundle having flexibility - Google Patents

Abstract

PURPOSE:To decrease the fracture of the fibers in the boundary part and to enable the bending of the forward end part at an acute angle by filling a flexible plastic in the boundary part between the end part and flexible part of a flexible optical fiber bundle having the end parts which are stuck to one body, and winding and reinforcing the outside circumference thereof with a linear member. CONSTITUTION:An elution preventive covering 20 is applied in both end parts of a fiber bundle obtained by heating and melt sticking an optical fiber bundle with tripple optical fibers each consisting of core glass 2, convering glass 3 and acid soluble glass 4 and stretching said bundle, whereafter the bundle is dipped in eluting liquid to elute the glass 4 whereby a flexible part 28 is formed in the bundle except the covering parts 20 in the end parts. The many optical fibers 22 in the end part 24a are stuck in one body by the acid soluble glass 24. A flexible plastic filler 29 is filled in the boundary part 25a with the flexible part and a linear member 27a such as cotton or the like is wound on a part 25b of the part 25a to reinforce the same. A reinforcing pipe 26a is fitted onto the end part 24a. The fracture in the part 25a is thus decreased and the bending of the forward end part at an acute angle is made possible.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical fiber bundle in which each optical fiber is fixed at its end and is flexible at a portion other than the end.

Currently, optical fiber bundles are used for image guides, double-light guides, etc., but when used as an image guide, each fiber must be correctly arranged in one-to-one correspondence at both ends in order to obtain a clear and correct image. There is a need to.

In particular, when the optical fiber bundle for image guide is used as an endoscope, the end portion is inserted so that it can be inserted for observation at any point inside the body cavity or inside the electrified hollow body inside the device. The other parts must be flexible, and the tip must be able to bend freely and at a steep angle. By the way, various methods have been proposed for manufacturing an optical fiber bundle that is flexible except for such ends and whose leading end can be bent freely and at a steep angle. For example, in the double-heavy industry (heating the gas in an outer composting pot to a material with a relatively low refractive index,
Pulling both glasses through the bottom hole of the conduit, coating the core glass with the coating glass, winding the obtained optical fiber into a row of loops without any gaps, solidifying one part of the loop with a T-containing agent, Wrap it in a loop shape in a line in the same way as before, fix it with adhesive at the fixed part of the previously formed loop, and repeat this operation to obtain a loop-shaped optical fiber bundle with the desired thickness. When the optical fiber bundle is assembled, approximately the center of the fixed part of the loop-shaped optical fiber bundle is
A method of manufacturing a flexible optical fiber bundle for an image guide is known, which comprises cutting a bundle at right angles to the outermost direction and polishing the two cut surfaces. In this method, the desired thickness can be obtained by heating 11g1.
(for example, 20 seconds) The subsequent process of arranging the optical fibers is extremely difficult and requires great skill to handle all the thin optical fibers, and the risk of cutting them is also high. However, the image guide using this method had the disadvantage of a poor yield and even higher costs. Alternatively, in addition to optical a-core glass with a relatively high flux, a coating glass with a relatively low refraction rate and a 5k4h outer diameter θ-planting pot can be used as an alternative method.
After heating to a temperature of 100 ft, the glass filter is poured through the bottom hole of the tower.
Then, by coating the core glass with a coating glass and coating the outer periphery with acid-soluble glass, an optical score (the diameter of this optical score is about 200sii degrees) is obtained, and a prestige score is obtained. Cut it into appropriate lengths (approx.
For example, the diameter of the optical IjRI7m is 1/Is by bundling G O (1) into 1 and heating and fusing it, and then heating it to an appropriate temperature.
Both ends of the hard optical fiber bundle thus obtained are coated with a plus 7 film to prevent elution, and then brought into contact with Ikko Seki-Togane Tai T-111 (for example, nitric acid) to form an optical fiber bundle. It consists of eluting acid-soluble glass from the middle part of the fabric. Compared to the above-mentioned method, in this method, the optical fibers can be arranged with a thickness of about 200 tones, so the arrangement is easy and the risk of breakage is extremely low.

Moreover, after the arrangement, the above-mentioned fear is completely eliminated because they are integrated by heat fusion. Therefore, this method has a higher manufacturing yield than the first method and can significantly reduce costs. This effect becomes more pronounced as the optical fiber becomes thinner. However, in this method, the valley fibers at the ends of the optical fiber bundle are bonded very tightly to the acid-soluble glass, so that some of the valley fibers at the ends of the optical fiber bundle are bonded very tightly to each other, compared to when they are bonded with plastic adhesive. 1lffl near the boundary with the flexible part is prone to breakage -
It has the disadvantage of becoming Various proposals have been made to overcome the above drawbacks.

For example, the vicinity of the boundary between the end of the optical fiber bundle and the flexible portion is covered with plastic having appropriate hardness and appropriate flexibility, and each 41i! Optical fiber bundle (%
Kosho 56-47526), Optical fiber bundle O end and mat
Optical fiber bundle with bending strength (% opening FF150-98344), optical fiber bundle with bending strength covered with a reinforcing pipe whose physical properties change continuously or in steps near the boundary with the part with which it is attached. By impregnating and curing the fibers of the 10m-dissolved part (insoluble residue) between the solid part and the flexible part of the 4th part, a polymeric substance with high hardness, good adhesion, and low viscosity is applied. An optical fiber bundle (partially reinforced by impregnating and curing a low-viscosity rubber elastic material near the outflow part of molecular substances)
(Japanese Patent Publication No. 56-48844), a liquid of a polymeric organic material having an appropriate hardness and flexibility for assimilation and solidification is applied to the outer periphery near the boundary between the end of the optical fiber bundle and the flexible portion. A method of reinforcing the edges by covering the mixture with rotten wood that will strengthen the polymer material that will be used later, and penetrating it in the center and length directions (
Tokuko Sho 5@-49327), etc. have been proposed.

However, these prior art techniques have various drawbacks as described below. In other words (Special Public Interest Publication No. 56-4731
In 26), it is difficult to bend the tip of the optical fiber bundle to the t-a angle because it is integrally covered with plastic near the boundary. (Japanese Patent Publication No. 50-98344), (Special Publication No. 50-98344)
6-49327) has almost the same drawbacks as (Japanese Patent Publication No. 56-47526). (41 Duke [56-488
44) has the disadvantage that the outer periphery of the boundary where the greatest stress is applied in the case of tip St bending fC is not reinforced, so that the fibers at the outer periphery break during use.

The present invention has been made in order to eliminate the above-mentioned drawbacks, and its purpose is to fix each end of each optical fiber together with acid-soluble glass or an inorganic adhesive, and to connect the end and flexible optical fibers together. Town 45I near the border with the sexual part! A wire member is wound around the boundary of at least one end of the outer part of the filling part to provide sufficient mechanical mIIL intermittently.
The objective is to provide an optical bundle that has flexibility by increasing the shoulder bendability of the tip at the same time. That is, the present invention provides a flexible optical fiber bundle in which optical fibers #m are integrally fixed at the end with acid-soluble glass or an inorganic adhesive, in the vicinity of the boundary between the end and the flexible portion. A plastic snack tie with flexibility between each optical fiber.
, and wrap at least the vicinity of the end side boundary of the outer periphery of the filled part with a linear member to make the end mechanically strong and flexible. The present invention relates to an optical fiber bundle having properties.

Next, the present invention will be explained in detail below with reference to the drawings.

First, the three mourning stories shown in Figure 142
In the axel jar, wax is placed in the inner pot @ a glass with a relatively high refractive index, namely core glass Sk, and in the middle pot 9 is a core glass 5 with a lower refractive index. Acid-soluble borosilicate glass T is charged into the four outermost tower pots 10, respectively. The core glass that can be used in real F14 is an example.

The material has the following composition and properties. Composition of core glass (ml t'lk); 5hot
: '45.0*, K, 0:ILO*, PbO:
24.0%, BaO2 110%, Zn
O: 5.0%, Al5o@:3, O
fk % AamOi 'α7-1 refractive index (ad): 1
．． 59062, dislocation point: 528℃, softening point: 583℃
, thermal expansion coefficient: 99X1G-' car/a++,
The C0 glass that can be used in the present invention has, for example, the following compositional properties. Composition of coated glass (n amount -); Stow: 6
4096, Na, O: 110%, Pbo: 12fO
Excellent, ho: &0% 1. utos: xo-1A
alO1: α7, refractive index (ad): 152852, dislocation point: 86°C, softening point: 533°C, coefficient of thermal expansion: 9
8 X 1 G '-' tx/cM, U.

The acid-soluble glass that can be used in the present invention has, for example, the following composition and properties. -Composition (weight -); mow: 1 & 5-15-1B
:3B5%, Nano :ILO*, BaO:
26-Ofk, Mu0: 7. Ofk % Am 10
m'0.3 excellent, refractive index (ad): L5j1090.
Dislocation point: 540℃, Softening point: s74℃, Coefficient of thermal expansion 29
2 X 10' ext/lvi, C.

Next, the triple carton t' containing core glass, coated glass, and acid-soluble glass is heated in the air furnace 11.
Heavy optical fiber 11t - Pulled with roller 12. FIG. 1 shows a diametrical cross-sectional view of the triple optical IR fiber 13 obtained. The outer diameter of the triad a#1 is about 20ζ, the thickness of the acid-soluble glass 4 is about 5, and the thickness of the covering glass 3 is about 20μ.

Next, cut this triple optical fiber 1 at approximately 300 + uK, and cut the optical fiber bundle (approximately io, ooo) so that the ends of each optical fiber correspond one-to-one. ) and heat-fuse it. Next, as shown in @31fi, the thermally fused optical fiber bundle is further heated and stretched. That is, the heat-fused and good optical fiber bundle 18 is sent downwards little by little with the roller 14, and its tip is heated in the air furnace 16 for about 70 minutes.
It is heated to 00CK to soften it and then stretched downward for 1 second. In this case, it is stretched to 1/15 gK of the stretching, that is, about 1.5 m. As a result, the diameter of each optical fiber is approximately 13μ.

Next, both ends of the obtained hard optical edge -'f-7 are entirely coated with a bath bleed-out prevention coating 20. Then, the entire optical fiber bundle coated at both ends is immersed in an elution treatment tank 21 for treatment, as shown in FIG.

The elution treatment is, for example, first treated with about 70℃ IN nitric acid for about 2 hours, then washed with water for about 10 minutes, and then treated with αS at about 35℃.
Treat for about 1 hour with NN*OHK, and then wash with water for about 1 hour again. Optical fiber bundle 1 made by the above elution process
Acid-soluble glass and insoluble residues other than the ai20 of No. 1 can be almost completely removed. Figures g & 5 are schematic diagrams of an optical fiber bundle imparted with flexibility by the above elution treatment, C21 indicates a flexible portion, and Figure $6 is a cross-sectional view showing an example of an optical fiber bundle according to the present invention; A large number of optical fibers 22 are integrally fixed to each other by soluble glass 24 at the end portion 24m. A boundary portion 25m between the end portion 24m and the flexible portion 2@ is filled with a plastic filler 29 having flexibility. Flexible plastic filler 2
For example, silicone adhesive (7 Silicone RT
V), or some of the epoxy resins such as Ciba's Akuru Daitom Y1G3 &iT! A suitable material is one containing a la agent.

Next Kq! One part 25bt of the edge sm of the outer periphery of the boundary i12 S a filled with a plastic filler 29 having It properties
Natural fibers (cotton, silk, etc.), synthetic fibers (nylon, etc.),
25g of the flexible part side of the boundary @ 2 S m is filled with a flexible plastic filler 29 and left as it is. Sequentially to the flexible part 2I #i] 'The flexibility is large,
In addition, a portion 25b near the end of the boundary II 2 S a is intermittently given sufficient mechanical strength and at the same time has high flexibility. Next, use 2s of adhesive to reinforce the end 24m.
It is fitted into the reinforcing pipe 26a through. supplementary pipe 2
For example, metal (aluminum is used as a substitute for stainless steel) is used as 6&.

With this structure, the mechanical strength of the boundary area is increased, and at the same time, the bendability is also increased, and stress is not applied to each fiber in this area, making it extremely resistant to bending, tensile stress, etc. It is possible to efficiently produce an optical kRiIa bundle that is strong against water and has great flexibility at the tip.

FIG. 7 is a cross-sectional view of the end of another embodiment of the present invention, in which an edge-like member 27b is placed near the end 24m of the boundary 25a filled with a flexible plastic filler 29.
t3 and reduce the number of layers of the 711st winding toward the flexible part 28, increasing the mechanical strength dLt on the end side - p greater than the flexible part side, and at the same time, J7Aii! Increase your i-ness. In FIG. 8, the same effect can be obtained by using a highly elastic cord material that is knitted from the end S side to the flexible portion side instead of the number of winding layers shown in FIG. 7. The objects of the present invention can also be achieved by appropriately combining the above embodiments.

No. 6.7.8.9, linear member 27a27b in the figure,
The winding of 27・, 21-1 starts from the boundary between the solid bed end 24m and the flexible Goufstick filled fc boundary #2 S m, but f! 1l-ytx44$ 24 Even if you start from one point within a, of course there will be no barley. Although the above-mentioned embodiments described the #output treatment as a combination of acid solution treatment and alkaline solution treatment, the purpose of the present invention can also be achieved with primary acid solution treatment. In addition, in the above embodiment, the triple optical #l model is made of acid-soluble glass! As mentioned above, this method is made by fixing the ends of multiple double optical fibers with an inorganic adhesive (e.g., silica, alumina-based water-soluble paste) and filling the optical boundary with flexible plastic. By winding the outer periphery of the filling part with a T-wire member at least near the boundary on the end side, the mechanical strength on the end side is made greater than that on the flexible part side, thereby reducing folding of the fibers at the boundary. The tip S can be bent at a steeper angle than before, making it very effective when manufacturing image guides for endoscopes that use the tip -m bent at an angle of repose K. It is something.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of the triple optical fiber, Figure A-42 is a schematic diagram of the process of heating the triple table and drawing the optical score, and Figure 3 is heating the optical fiber bundle that has been fused with PA. Figure 4 is a schematic diagram of the drawing process. Figure 4 shows the process of elution treatment of acid-soluble glass. A schematic diagram, FIG. 6 is a cross-sectional view of a main part showing one embodiment of an optical fiber bundle to which the present invention is applied or has the same structure, and FIGS. 7, 48, and 9 show other embodiments.
11 is a sectional view. 1.13... Triple optical fiber, 2.5... Core 11.
16...Electric furnace, 12.14ζ15...Roller,
1T...Optical fiber bundle, 1@...Heat-fused optical fiber bundle, 1-...Treatment ffl liquid, 20...Coating, 21
...Processing tank, 22...Double optical fiber, 2s...Adhesive, 24h...Fixed end, 25a...Boundary part filled with flexible plastic, 16&, 21b,
2@1ls2 @d ・・・Supplementary “strong vibe, 27&’;
zyb. 27c, 274... Linear member, 21... Flexible part, 2
s...Plastic filler material with town JIa properties J figure ¥J 4 Figure V, 5 Figure B Figure

Claims (2)

[Claims] (1) In a flexible optical fiber bundle in which each optical fiber is integrally bonded at the end with acid-soluble glass or an inorganic adhesive, each of the optical fibers near the boundary between the end and the flexible portion A flexible plastic is filled between the optical fibers, and a linear member is wound around the outer periphery of the filled material at least a little near the edge to the boundary to reduce the mechanical strength of the end portion. An optical fiber bundle having flexibility with a characteristic of increasing t%. (2) At least one of the cross-sectional area, interval pitch, number of turns, and material of the material of the linear member described in paragraph 1 is different in the axial direction, and the mechanical strength of the end is greater than that of the flexible part. The flexible f! according to claim 1, characterized in that the flexible f! Optical fiber bundle with I.