JPH0193709A - Tape type optical fiber - Google Patents

Abstract

PURPOSE:To facilitate the operation for removing a coating layer and to reduce the cost of optical fibers by using a material having the tensile strength and elongation of about the level at which the coating layer can be broken and removed by human fingertips as the coating layer. CONSTITUTION:The tape type optical fiber 1 has the structure in which, for example, 4 pieces of fibers 2 disposed on the same plane are coated by the coating layer 3 made of a synthetic resin. Said fiber has the sectional shape which is flat as a whole. The low-strength material is used as the resin material constituting the coating layer 3 so that the coating layer 3 can be broken in the state of nearly a kind of brittle fracture only by the human finger force. The need for a special tool is, therefore, eliminated in the case of removing the coating layer 3. In addition, there is no need for previously coating a release agent between the fibers 2 and the coating layer 3 in the production stage and, therefore, the production cost is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a tape-shaped optical fiber core wire having a flat cross-sectional shape.

(Prior Art) Generally, a tape-shaped optical fiber core is composed of a plurality of strands arranged on the same plane and a resin coating layer having a flat cross-section that covers the strands. A plurality of such optical fiber cores are stacked and housed in a slot of a rod-shaped holder.

When connecting tape-shaped optical fibers, it is necessary to remove the coating layer to expose the fiber body inside the strands. Therefore, it is preferable that the coating layer has a structure that is easy to remove, and for this purpose, it has been conventionally proposed to use a mold release agent between the coating layer and the wire.

(Problems to be Solved by the Invention) However, when a mold release agent is used, there is a problem that the manufacturing process of the optical fiber core becomes complicated and the manufacturing cost increases.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a material for the coating layer of a tape-shaped optical fiber core that can be used with a force that can be directly applied to the coating layer from a human fingertip. The material is characterized in that a material having such tensile strength and elongation that the coating layer is destroyed and separated from the outer peripheral surface of the wire is selected.

(Function) According to the above configuration, the covering layer can be destroyed and removed with a human finger, so the removal work of the covering material can be easily performed.

(Example) The tape-shaped optical fiber core shown in FIG. It has a cross-sectional shape. Each strand 2 has a circular cross-sectional shape, and a fiber 5 located at the center and a fiber 5
It is provided with a covering part 6 surrounding the. The covering part 6 is made of a synthetic resin material and has a two-layer structure including an inner layer 7 and an outer layer 8.

According to the present invention, a low-strength material is used as the resin material constituting the coating layer 3, and the coating layer 3 can be broken into a kind of brittle fracture with just the force of a human finger (for example, just by "squeezing"). It is designed so that it can be destroyed (so as to destroy the coating layer 3) in a state close to .

In addition, the material of the coating layer 3 is such that the fragments generated by the destruction are
It has a property that it does not adhere (or does not adhere easily) to the surface of.

Therefore, when removing the coating layer 3, no special tool is required, and there is no need to apply a mold release agent between the strands 2 and the coating layer 3 during the manufacturing stage.

Note that during the manufacturing stage of the optical fiber core 1 or when inserting the core wire 1 into the slot of the holder, the optical fiber core 1
A force is applied to the cover layer 3, but the coating layer 3 has enough strength to not be destroyed by such force alone.

Next, the material of the coating layer 3 will be explained in more detail based on the test results conducted by the inventor of the present invention.

The mechanical properties of materials A-G used as test articles are as follows.

Further, the core wire used in the test was 4 cores, and the outer diameters of the inner layer and outer layer were 200μ and 250μ, respectively.

First, as a result of testing materials A and B, material A is capable of single core separation (destruction and removal of the coating layer), but its strength is too low, making it mechanically unstable, making it impractical. It turns out there isn't. Also, material B was tested as a material with the mechanical instability of material A removed, but its strength was too high and it was impossible to separate it by "straining" or the like.

Based on the above results, experiments were conducted on materials C, D, and H.

In conclusion, it has been found that these materials C, D, and E all satisfy the above-mentioned conditions of the present invention as a coating layer.

However, material C was easier to separate than material porcelain, and material porcelain was easier to separate than material E.

Considering the results regarding the separability (ease of separation) of materials C and D and the mechanical properties of both materials, the Young's modulus of material C is greater than that of material C, and the tensile strength of material C is greater than that of material C.
Since this is smaller than the material thickness, it can be inferred that the separability is influenced not by Young's modulus but by tensile strength or other factors.

Furthermore, in general, it is more advantageous for the coating layer to have a higher Young's modulus in terms of the optical properties of the optical fiber, so of the above three types of materials, material C is most suitable as the coating layer.

In addition to the above three types of materials, experiments were conducted on materials F and G, and as a result, material G was found to be good as a material having similar characteristics. In addition, material H had too high a Young's modulus and suffered from support during the process of making a cable.

From the above, there are still some points that are not clear, but as for material properties, Young's modulus is 0. 65kg/mm2 or more, tensile strength 1. 00 kg/m02 or less and elongation rate of 70% or less are considered preferable.

(Effects of the Invention) As described above, according to the present invention, the coating layer 3 can be easily removed without using any special tools, so that cable connection work and the like can be simplified.

Moreover, since it is not necessary to apply a mold release agent between the strands 2 and the coating layer 3, the manufacturing cost of the optical fiber core 1 can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of the embodiment. 1...Optical fiber core wire, 2...Element wire, 3...Coating layer Patent applicant Mitsubishi Cable Industries Co., Ltd. Representative Patent attorney Tadataka Omori ゛Figure 1

Claims (1)

[Claims] In a tape-shaped optical fiber core wire comprising a plurality of strands arranged on the same plane and a resin coating layer covering the plurality of strands, the material of the coating layer is a material that flows from a human fingertip to the coating layer. A tape-shaped optical fiber core wire characterized in that a material having a tensile strength and elongation rate of such a degree that the coating layer is destroyed and separated from the outer circumferential surface of the wire by a force that can be directly applied is selected.