JPS6177021A - Production of image guide - Google Patents

Abstract

PURPOSE:To remove completely foreign matters or the like from the surface of strand fibers by arranging a positioning member provided with an inscribed plate which is brought closely into contact with the inside peripheral surface of a glass pipe, a small-diameter contacting plate which is supported apart from the inscribed plate, and an air hole provided in the inscribed plate in the glass pipe. CONSTITUTION:A positioning member 1 provided with an inscribed plate 2 which is brought closely into contact with the inside peripheral surface of a quartz pipe 6, a small-diameter contacting plate 4 supported apart from the inscribed plate 2, and an air hole 5 which pierces the inscribed plate 2 in the position corresponding to the contacting plate in the thickness direction is arranged in one end side of the quartz pipe 6, and end faces of plural strand fibers 7 are brought into contact with peripheral surface sides of the contacting plate 4 and the inscribed plate 2, and plural strand fibers 7 are arranged and packed in the quartz pipe 6. The quartz pipe 6 is heated by a burner 8 and is subjected to etching processing while press-feeding an etching gas from the other end into the quartz pipe 6, and the quartz pipe 6 is fused by heating to join clads of individual strand fibers 7 and the quartz pipe 6 into one body.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a method of manufacturing an image guide made of a plurality of bare fibers.

(Technical background of the invention) As a method for manufacturing an image guide, a plurality of bare fibers are arranged and filled in a glass pipe, and the glass pipe is collapsed by reducing the pressure inside the glass pipe while heating the bare fibers and the glass pipe. There are known methods in which the claddings of each elemental fiber are integrated and then further spun, or methods in which the collapse step is omitted and the claddings are integrated while directly spinning.

By the way, a bare fiber for an image guide may have foreign substances such as organic matter attached to it or may be scratched, so when manufacturing an image guide using such a bare fiber as it is, Bubbles are generated and the mechanical strength is reduced. For this reason, conventionally, after filling a glass pipe with a plurality of bare fibers, etching gas is pumped into the glass pipe to remove foreign matter adhering to the bare fibers and scratches on the surface of the fibers. However, in order to carry out the etching process, it is necessary to open both ends of the glass pipe to allow the etching gas to flow, so it is possible to line up and fill a plurality of bare fibers into the glass pipe with one end aligned. It is difficult to do so, and there is also the problem that the bare fibers may shift in the axial direction or come out when the etching gas is pumped or the pressure is reduced when the cladding of the bare fibers is integrated.

Therefore, recently, a porous partition plate made of glass is installed inside the glass pipe (see Japanese Patent Publication No. 58-31568). This allows one end of each strand fiber to be brought into contact with the partition plate and aligned, and the etching gas This is to prevent the strands of fiber from shifting or coming off during pressure feeding.

(Problems with the background art) However, when using porous partition plates like this,
Since the hole diameter is even smaller than the diameter of a small-diameter bare fiber, if the flow rate of the etching gas pumped into the glass pipe is large, the pressure inside the pipe will become extremely large, resulting in damage to the bare fiber. When etching gas is forced into the glass pipe at a large flow rate while heating the bare fiber to its softening point temperature in order to completely remove it, the glass pipe expands due to the internal pressure. When used, it is necessary to heat the bare fiber to a temperature below its softening point and to reduce the etching gas flow rate. Therefore, it is impossible to completely remove foreign objects and scratches from the bare fiber.

Additionally, when integrating the cladding of bare fibers, glass raw material gas is pumped into the glass pipe.

It is also practiced to provide a glass layer on the bare fiber bundle in advance, but in this case, fine glass powder is generated in the glass pipe, so the partition plate is easily clogged with this fine glass powder and the foreign matter. I wake up.

Furthermore, since the partition plate has a porous structure, it is very fragile, and therefore, when the partition plate is fused and fixed to a glass pipe, there is a drawback that pieces of the partition plate are scattered into the pipe.

By the way, it has also been proposed to perform etching treatment on bare fibers by making holes in the circumferential surface of a glass pipe with one end closed (see Japanese Patent Application Laid-Open No. 150930/1983). Harmful etching gas and reaction products are directly discharged outside the glass pipe, so a separate exhaust mechanism is required to cover the entire glass pipe, and it is difficult to integrate the cladding of each bare fiber. Even when the pressure is reduced, it is necessary to connect the glass pipe to an exhaust passage or the like while maintaining airtightness, which poses problems in terms of workability and economy.

(Objective of the Invention) The object of the present invention is to be able to completely remove foreign matter etc. from the surface of a bare fiber, to prevent problems such as clogging and scattering of fragments in the glass pipe, and to improve workability. The object of the present invention is to provide a method by which a good image guide can be manufactured.

(Summary of the Invention) The present invention provides a circumferential plate that is in close contact with the inner peripheral surface of the pipe, a small-diameter abutment plate supported at a distance from the circumferential plate, and a contact plate of the circumferential plate. A positioning member is arranged to connect the contact plate and a ventilation hole provided at a position facing the contact plate, and each end surface of the plurality of bare fibers is brought into contact with the contact plate and the circumferential surface side of the circumferential plate. By arranging and filling the pipe, the raw fibers are heated to their softening point temperature while a large amount of etching gas is pumped into the glass pipe and discharged from the vent hole. (Embodiments of the Invention) Examples of the present invention will be described in detail below with reference to the drawings.

First, the positioning member 1 shown in FIGS. 1 and 2 was prepared. That is, this positioning member 1 includes a circumferential plate 2 made of a glass disk and having a diameter of 20 mm.

This circumferential contact plate 2 has a thickness of 2+am, and a contact plate 4 made of a glass disk and having a diameter of 17 cm is attached coaxially to one side of the circumferential plate 2 through a support part 3 with an interval of 1 cm. and are supported in parallel. This contact plate 4 has a thickness of 1ffIm. A plurality of ventilation holes 5 are provided on the inner peripheral side of the one-circumference contact plate 2 facing the contact plate 4, which penetrates in the thickness direction thereof. Each vent hole 5 has a diameter of 5 mm.

Next, as shown in FIG. 3, the positioning member 1 is placed on one end of a quartz tube 6 with an inner diameter of 20 mm and a wall thickness of 2+++ m, and the contact plate 4 is protruded from the other end of the quartz tube 6. Since it does not have a porous structure, no glass fragments are generated when it is fixed to the quartz tube 6.

In this way, after fixing the positioning member 1 to the quartz tube 6, 4000 quartz-based bare fibers 7 having an outer diameter of 3008L11 were inserted into the quartz tube 6 from the other end, arranged, and filled into the 00 quartz tube. Since the positioning member 1 is fixed to one end side of the inner fiber 6, the plurality of bare fibers 7 located in the center
Each end face of the fibers 7 contacts the contact plate 4, and each end face of the plurality of bare fibers 7 located on the outer periphery of the fibers 7 contacts the circumferential surface of the circumferential contact plate 2.

Therefore, 4000 bare fibers 7 can be easily aligned and filled with one end thereof aligned in the quartz tube 6.

Next, attach the first quartz tube 6 to a glass lathe (not shown) and inject etching gas into the first quartz tube 6 from the other end.
The quartz tube 6 was heated to about 0.degree. C. by a burner 8 while pumping oxygen (oxygen) gas, and rotated by a glass lathe. This removed foreign matter such as organic matter on the circumferential surface of the bare fiber 7, but even if the 02 gas flow rate was increased, the diameter (5 mm) of the vent hole 5 in the circumferential plate 2 was large, so the quartz tube 6 would not expand. There wasn't.

Next, the quartz tube 6 was heated at about 1000° C. and rotated while CF gas was pumped as an etching gas into the quartz tube 6, thereby removing scratches on the circumferential surface of the bare fiber 7. In this case as well, although the CF and gas flow rates were increased, the quartz tube 6 did not expand.

After performing the etching process in this way, BB r3 gas, SiCM+ gas, Ar and 0
The quartz tube 6 was heated to about 1,400 DEG C. to 1,500 DEG C. by the eighth while supplying the mixed gas of □, and a glass layer made of B2O3-3tCQ was provided on the bundle of bare fibers.

In this case, since the vent hole 5 had a large diameter, it was not clogged with glass fine powder.

Then, the other end of the quartz tube 6 is closed by heating, melting, and crushing, and one end of the quartz tube 6 is connected to a vacuum pump (not shown) to reduce the pressure inside the quartz tube 6 to approximately 0°2 Torr. The quartz tube 6 was heated and melted by a burner 8 at a temperature of 1700° C. to 1900° C., and the clad of each strand fiber 7 and the quartz tube 6 were integrated to produce a guide member.

Finally, the guide member obtained by collapsing was placed in a carbon resistance heating furnace, heated at 1800° C. to 1900° C. to melt it, drawn by a take-up roller, and spun. This results in a 1 m outer diameter with 4000 cores.
I got an image guide for m.

When the obtained image guide was examined, it was found that there were no pixel defects such as bubbles, and the mechanical strength was excellent, with a fracture diameter of 30 mm or less. This means that by increasing the flow rate of 0□ gas or CF4 gas and heating the bare fiber 7 (quartz tube 6) to a softening point temperature of 1000°C, we were able to completely remove foreign objects and scratches. This is thought to be due to the following.

In the above embodiment, a glass layer is provided on the bundle of bare fibers 7, but it is not necessarily necessary to provide the glass layer, and the cladding of each bare fiber 7 may be directly integrated.

Further, in the above embodiment, the step of integrating the cladding of each strand fiber 7, that is, the collapse step, may be omitted and direct spinning may be performed to integrate the cladding of each strand fiber 7.

(Effects of the Invention) According to the present invention, a circumferential plate that is in close contact with the inner circumferential surface of the pipe, a small-diameter abutment plate that is supported at a distance from the circumferential plate, and a circumferential plate that is provided in a glass pipe. By disposing a positioning member having a ventilation hole provided at a position opposite to the abutting plate, etching gas is pumped into the glass pipe at a large flow rate and the bare fiber is heated to the softening point temperature. In addition to being able to perform a complete etching process, it is also possible to effectively prevent glass fine powder and the like from clogging or scattering as fragments in a glass pipe such as a porous partition plate. Furthermore, when the positioning member is disposed inside a glass pipe, an exhaust mechanism, an exhaust path, etc. for covering the glass pipe are not required. Therefore, an image guide having no pixel defects and excellent mechanical strength can be manufactured easily and economically.

[Brief explanation of the drawing]

FIG. 1 is a front view of the positioning member used in the manufacturing method of the present invention, FIG. 2 is a sectional view taken along line A-A in FIG. 1, and FIG. 3 is a sectional view showing how the positioning member shown in FIG. 1 is used. be. 1----------1 positioning member, 2---------One round contact plate, 4---1--Abutting plate, 5-1--------- Ventilation hole, 6------- Quartz tube. 7 ---------- Bare fiber. (1 other person) Fig. 1 Fig. 2 Fig. 3 Written amendment to the handbook (voluntary) June 22, 1985 Mr. Manabu Shiga, Commissioner of the Patent Office” 1. Case Indication Patent Application No. 1981-199180 2. Name of invention manufacturing method for image guide 3, relationship with the case of the person making the amendment Patent applicant Showa Electric Wire and Cable Co., Ltd. 4, agent 3-7-6-5 Mejiro, Toshima-ku, Tokyo, “ "r1000°C" in Column 6 of "Detailed Description of the Invention", page 8, line 16 of the Specification of Amendment, page 9, lines 3-4, and page 10, line 13, is corrected to "r1500°C". that's all

Claims (1)

[Claims] 1. A step of arranging and filling a plurality of bare fibers into a glass pipe, and pumping an etching gas into the glass pipe from one end thereof while heating the glass pipe at a predetermined temperature. , a step of etching the surface of the plurality of plain fibers, and a step of reducing the pressure in the glass pipe, heating the plurality of plain fibers together with the glass pipe, and integrating the cladding of each of the plain fibers. A method for manufacturing an image guide, comprising: a circumferential contact plate on the other end side of the glass pipe that is in close contact with an inner circumferential surface of the glass pipe;
a positioning member having a small-diameter abutting plate supported at a distance from the circumferential plate; and a ventilation hole extending through the circumferential plate in the thickness direction at a position facing the abutting plate; Arranged,
An image characterized in that each end surface of the plurality of strand fibers is brought into contact with the peripheral surface side of the abutment plate and the circumferential plate, and the plurality of strand fibers are arranged and filled in the glass pipe. Guide manufacturing method. 2. The step of integrating the cladding includes a pretreatment step of heating the glass pipe and pumping frit gas into the glass pipe to form a glass layer on the bundle of the plurality of strand fibers. A method for manufacturing an image guide according to claim 1, comprising: