JPS5910907A - Optical fiber device - Google Patents

Abstract

PURPOSE:To improve airtightness with simple construction by impregnating a synthetic resin into a bundled optical fiber, and forming a penetration terminal board of a synthetic resin in one body with the bundled optical fiber. CONSTITUTION:A resin compsn. prepd. by compounding only the hardener with epoxy resin of low viscosity is impregnated under vacuum in the part removed of a protective covering layer 12 of a bundled optical fiber bundled with several tens to several thousand pieces of optical fiber cores 111 provided with glass type clad layers 112 at a degree of vacuum up to about 5mm.Hg, and is cured at temp. up to 100 deg.C. On the other hand, an epoxy resin compsn. compounded with a filler and a hardener is prepd. at temp. up to 100 deg.C, and is cast under vacuum and cured at <=100 deg.C under <=5mm.Hg pressure in a preheated die, and when the molding is released from the die, an optical fiber penetration type hermetic terminal board is obtd. The cast resin and the impregnated resin are thoroughly made into one body.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical fiber device comprising a nozzle-shaped optical fiber having a glass-based cladding layer such as quartz glass or multi-component glass, and in particular to airtightness of a terminal plate through which an optical fiber is passed through. Related to pressure-resistant structure.

In recent years, the range of applications for optical fibers has increased significantly, and in addition to general communications applications, they are also beginning to be applied to heavy electrical equipment. l. For high-voltage switching equipment that uses gas, electrical equipment related to transformer DC power transmission, etc., it is necessary to convert optical signals and electrical energy into light and introduce them into a tank filled with high-pressure SF6 gas. ing. In such cases, the inside of the tank is generally 6 kg/cm in order to maintain insulation properties.
Although SF6 gas or the like is sealed at a constant pressure of less than d, gas leakage is absolutely not allowed through ordinary bushings for conducting electricity or through these optical fiber penetration parts.

Conventionally, there are not many examples of such applications for optical fibers, and even if there were, inorganic materials such as copal were used in the quartz-based node layer of a single type optical fiber, and the bonding with the glass layer and the metal tank were used. The only thing that could be seen was that the parts were bonded and sealed.

This invention attempts to mold a penetrating portion of a bundle-shaped optical fiber that is excellent in airtightness and pressure resistance by using only synthetic resin such as epoxy casting material.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. That is, in FIG. 1, (1) is a bundle-shaped optical fiber consisting of a core wire 0υ and a protective coating layer (2) made of hynyl chloride or polyethylene that covers the outer layer of this core wire 01), and (2) is a bundle-shaped optical core ( This is a multi-pole through-type airtight terminal board formed integrally with l<(1) and having a mounting hole QI) and an O-line groove, molded with cast resin. Here, the core wire 0υ of the vanodle optical fiber i It is formed by bonding fiber cores (Ul) with an epoxy resin adhesive (U3). Further, if necessary, as shown in FIG. 8, a coupling agent layer (114) treated with a coupling agent such as cyano or borane is formed on the outside of the cladding layer (112).

In this bundle type optical fiber, the core diameter is generally from about 10 μm to about 0.5 μm, and the number of bundled fibers ranges from tens to thousands of fibers. An airtight structure cannot be easily achieved using conventional sealing methods. For example, welding with inorganic materials such as copal may be theoretically possible, but in practice it is possible to weld only a few welds, and it is almost impossible if we weld more than a few dozen welds.

Furthermore, normal fibers are easily damaged by external factors, so they are coated with a protective coating layer θ. Since the voids are air permeable, it is impossible to achieve airtightness by simply applying a coating layer to the outside (even if epoxy resin is cast on the outside).Furthermore, even if this protective coating layer is removed, Even when casting a single piece, there are only a few optical fiber cores.If it is 4F, the resin will enter between the fibers and it will be possible to maintain an airtight surface, but if there are tens to thousands of fibers, it will be possible to maintain an airtight surface. In some cases, it is almost impossible to completely fill the spaces between the fibers with resin due to the relationship with resin viscosity and the effect of the filler (inorganic powder at about 100 μm) present in the casting resin.

Therefore, like the one in this example, an optical fiber core (■1
) are bundled together from tens to thousands of bundles of light bulbs 82.
A resin composition prepared by blending only a curing agent with a low viscosity epoxy resin such as No. 8 was applied in advance to the area from which the protective coating layer (2) had been removed.
Vacuum impregnation at a vacuum level of shoulder + IHg, 100°C
Let it harden at a temperature of up to

In general, it has been confirmed that if the viscosity of the resin used in the vacuum impregnation treatment is 100 Cp or less, the resin can be sufficiently impregnated between the glass fibers. In this case, if a silane-based or borane-based coupling agent is applied to the glass-based cladding layer by soaking it in advance as shown in Figure 8, it is possible to bond the epoxy resin and the glass-based cladding layer. 1m, and good results can be obtained.

Such pretreatment is similar to glass fiber reinforced FIul.
) When manufacturing glass fibers, glass fibers are pretreated with polyester resin or epoxy resin.
No abnormalities such as separation, cracking, or peeling are observed between the core layer and the resin layer. That is, since the optical fiber cores are completely sealed with resin and the gaps are filled with resin, airtightness is achieved.

After incorporating and fixing one or more bundle-shaped optical fibers configured in this way into a mold of the desired shape,
Preheat to a temperature at which there is no color tube in the protective coating, ie up to 100°C. On the other hand, an epoxy resin composition containing a filler and a curing agent was adjusted at a temperature of up to 100'C and placed in a preheated mold at a pressure of less than FsytBg for 100'
After vacuum casting and curing at a temperature below c, the mold is released to obtain an optical fiber through type airtight terminal plate. In this case, the casting resin part and the impregnated resin are completely integrated.

The optical fiber penetrating type airtight terminal board obtained in this way has excellent properties such as light transmittance, airtightness, crack resistance, etc., even after various thermal stress tests such as heat cycling, high temperature heating, low temperature cooling, and pressure resistance tests. No deterioration is shown in this test.

Further, the bundle type optical fiber can be manufactured in the same manner regardless of whether it is a single-pole type or a multi-pole type optical fiber. Furthermore, once the joint mold is created, the mounting hole for the flange part and the O-ring groove can also be integrally molded at the same time, which makes it possible to simultaneously mold the mounting hole of the flange part and the O-ring groove. Compared to other products, the process is simple and much cheaper.

As described above, the optical fiber device according to the present invention includes a bundle-shaped optical fiber l having a plurality of optical fiber cores coated with a glass-based cladding layer and a synthetic resin, and
The terminal plate through which the bundled optical fibers pass is integrally formed with the bundled optical fibers (molded from synthetic resin), which not only provides a simple and inexpensive structure, but also provides good airtightness.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional front view of an embodiment of the present invention;
FIG. 2 is an enlarged cross-sectional view of the main part of the one shown in FIG. 1, and FIG. 8 is an enlarged cross-sectional view of the main part corresponding to FIG. 2 showing another embodiment of the present invention. In the figure, (1) is a bundle type optical fiber, (II) is a core s, (2) is a protective coating layer, (111) is an optical fiber core, (112) is a cladding layer, (11B) is an adhesive, (2)
) is a hermetic terminal board. Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent Shin Kuzuno −

Claims (3)

[Claims] (1) A nodle-shaped optical fiber having multiple optical fiber cores coated with a glass-based cladding layer and impregnated with a synthetic resin, and a synthetic resin integrally molded with this bundle-type optical fiber so as to pass through the fiber. Fiber optic equipment with a terminal board that is eroded. (2) The optical fiber (device) according to claim 1, wherein the resin impregnated into the bundle-shaped optical fiber and the resin constituting the terminal board are both epoxy resins. (3) Claims in which the floor protection ff layer is removed from the portion of the bundle-type optical fiber that passes through the terminal plate.