JPH0410563Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an optical fiber cord having good heat resistance, cold resistance and mechanical properties.

[Technical background of the invention and its problems] Conventionally, as an optical fiber cord, as shown in FIG. It is known that Kevlar (polyaramid fiber (trade name: EIDupont)) is provided along the outer periphery as a tension member, and a soft vinyl chloride resin layer 5 is extruded and coated on the outside as a protective coating.

However, in such conventional optical fiber cords, there is a problem that the soft vinyl chloride resin loses its elasticity at low temperatures (below -10℃), resulting in deterioration of its mechanical properties against bending and impact. There is a problem in that the transmission loss of the optical fiber 1 increases because the vinyl resin contracts at low temperatures. In addition, the soft vinyl chloride resin layer 5 is
The properties of the polyamide resin layer 3 deteriorate at temperatures above 60° C. and above 80° C., resulting in the problem that the transmission loss of the optical fiber 1 increases over time.

On the other hand, fluororesin is known as a synthetic resin with good heat resistance and cold resistance, but since fluororesin has a large coefficient of linear expansion, it causes stress to the optical fiber when there is a large change in environmental temperature. However, there was a problem in that it caused transmission loss.

[Purpose of the invention] The present invention was made to solve these conventional difficulties, and has good characteristics at high and low temperatures.
The object of the present invention is to provide an optical fiber cord whose characteristics do not change much even when the environmental temperature changes.

[Summary of the invention] In other words, the optical fiber cord of the invention has an optical fiber wire consisting of a core and a cladding.
By sequentially providing a silicone resin layer, a fluororesin layer, a silicone resin layer, a tension member layer, and a fluororesin layer, the characteristics at high and low temperatures are improved, and the characteristics are also large even when the environmental temperature changes. It is designed not to change.

[Embodiments of the invention] Hereinafter, embodiments of the invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of the present invention.

In the figure, 11 is an optical fiber made of quartz glass with a core diameter of 50 μm and a cladding diameter of 125 μm;
12 is an outer diameter of 0.4 on the outer periphery of this optical fiber wire 11.
It is a silicone resin layer coated with a thickness of mm. The outer periphery of this silicone resin layer 12 is further coated with a fluororesin layer 13 with an outer diameter of 0.7 mm and a silicone resin layer 14 with an outer diameter of 1.2 mm. , high tensile strength fibers 15 such as glass fibers, etc. are laid along the fibers 15 .

16 is a fluororesin layer of a protective sheath which is loosely extruded and coated on these outermost layers to have an outer diameter of 3.0 mm.

The above fluororesin is ETFE (ethylene-tetrafluoroethylene copolymer extrusion temperature
240-330℃), PFA (tetrafluoroethylene-
Examples include fluoroalkyl vinyl ether copolymer (extrusion temperature: 290 to 380°C), FEP (tetrafluoroethylene-hexafluoropropylene copolymer, extrusion temperature: 270 to 360°C), and the like.

Note that the above-mentioned coating thicknesses may be changed as appropriate depending on the intended use and use.

[Effects of the invention] Since the optical fiber cord configured as described above has two fluororesin layers 13 and 16, the loss of the optical fiber 11 does not increase even at high temperatures. Furthermore, although fluororesin has a large linear expansion coefficient, the inner fluororesin layer 13 has a small linear expansion coefficient than the silicone resin layers 12 and 14.
Since it is sandwiched between the two terminals and its movement is restricted, there is no increase in transmission loss. Furthermore, the silicone resin layers 12, 14 and the fluororesin layers 13, 16 used in the present invention both have excellent heat resistance and cold resistance, so they can withstand severe temperature changes and maintain good properties over a long period of time. can be maintained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of the present invention, and FIG. 2 is a sectional view of a conventional optical fiber cord. 11... Optical fiber wire, 12, 14... Silicone resin layer, 13, 16... Fluorine resin layer, 1
5...Tension member.

Claims (1)

[Scope of claims for utility model registration] (1) On the outer periphery of the optical fiber consisting of a core and a cladding, a silicone resin layer, a fluororesin layer,
An optical fiber cord characterized in that a silicone resin layer, a tension member layer, and a fluororesin layer are provided in this order. (2) The optical fiber cord according to claim 1, wherein the tension member layer is made of high tensile strength fiber. (3) Utility model registration claim 1 or 2, in which the outermost fluororesin layer is loosely covered.
Fiber optic code as described in section. (4) The optical fiber cord according to any one of claims 1 to 3, wherein each fluororesin layer is extrusion coated.