DE8122786U1 - OPTICAL TRANSMISSION ELEMENT WITH A TWO-LAYER TUBULAR COVER - Google Patents

Description

SIEMENS AKTIENGESELLSCHAFT Our mark

Berlin and Munich

* l G 6 5 O 2 OE

Optical transmission element with a tubular casing consisting of two layers.

The innovation relates to an optical transmission element with at least one fiber-shaped optical waveguide, the inside of a tubular envelope consisting of two layers (inner layer and outer layer) is arranged.

A transmission element of this type is known from DE-AS 26 28 070. There the inner layer consists of an ethylene-chlorotrifluoroethylene copolymer, while the outer layer is made up of polyethylene terephthalate is. By adding a covering made of high-strength plastic threads and an outer sheath, it becomes from the optical transmission element a single-core optical cable, the fiber-shaped optical waveguide is loosely attached inside the tubular envelope.

In the case of such tubular casings made up of at least two layers, there is a problem in that under bending stress the two layers do not adhere to one another firmly enough and move against one another or detach from each other. This creates the risk that. it kinks at the separation point comes, which can lead to damage or impairment of the fiber-shaped optical waveguide. Farther is such an optical transmission element

Jb 1 Korn / 07/27/1981

4 k «»

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not gas-tight because the insufficient bond between the inner layer and the outer layer leads to the formation of in Allows gas channels running longitudinally.

The present innovation is based on the object of providing an optical transmission element of the type mentioned at the beginning Art to develop so that a secure and firm adhesion between the inner layer and the outer layer is guaranteed. According to the innovation, this is mentioned at the beginning in the case of an optical transmission element Kind achieved in that the inner layer is made of a high molecular weight polyester rubber and the outer layer a crystallizing polyester layer, so that there is firm adhesion between the two layers.

In this way, there is a permanent mechanical connection between the inner layer, even when it is bent and the outer layer ensured, so that delamination phenomena Od. Like. And associated undefined buckling processes can be avoided. The adhesion between the two layers is so strong that the resulting transmission element is gas-tight.

The inner layer consists in the innovation of a soft material (polyester rubber), sp that there is a relative low modulus of elasticity can be set. So that the inner layer is sufficiently strong, but still practically rubber-elastic, so that the impact resistance of the optical transmission element is positively influenced. A polyterephthalate can expediently be used as the material for the inner layer, preferably the product known under the trade name Arnitel EM 740 from AKZO can be used. This also has the advantage that it is sufficiently resistant to swelling against filling compounds which get into the interior of the

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g sheath and the optical fiber

^ Embed accordingly softly. Such a filling

fi is necessary above all when the optical

p transmission element should be made gas-tight.

I. A particular advantage is that the for I needed the two layers of materials relatively

I are inexpensive, so that in addition to an improved structure

I and more favorable properties the invention

I 10 transmission element can also be produced with less effort is.

In the drawing, there is an optical transmission element in cross section shown after the innovation. The fiber optic fiber optic cable provided with a BS coating LW is embedded in a viscous filling compound FM. The tubular casing consists of a Inner layer IS and an outer layer AS. The inner layer IS is made of a high molecular weight polyester rubber 20 produced, which must be sufficiently resistant to swelling against the substances of the filling compound I, FM. The outside I layer AS is a crystallizing polyester layer

I built so that between the inner layer IS and the

Ϊ Outer layer AS there is a firm adhesion that too

I 25 for compression processes caused by bending I is not resolved. AS is preferred as the outer layer

I polyterephthalate, especially polybutylene terephthalate

I (PBTP) is used, which has a sufficiently high elastic

Identity module and at the same time also source-resistant

I 30 dig compared to the filling compound FM, which is the relative [? soft polyester rubber penetrates the inner layer IS.

I 1 figure

$ 6 protection claims

Claims (6)

* »Re t - 4 - VPA Bt G 6 5 O 2 OE protection claims. VPA 1. Optical transmission element with at least one fiber-shaped optical waveguide, which is arranged within a tubular sheath consisting of two layers (inner layer and outer layer), characterized in that the inner layer (IS) from a high molecular weight polyester rubber and the outer layer (AS) from a crystallizing polyester layer, so that there is firm adhesion between the two layers is. 2. Optical transmission element according to claim 1, characterized in that the Inner layer (IS) has a low Ε modulus. 3. Optical transmission element according to one of the preceding claims, characterized in that that the outer layer (AS) consists of polybutylene terephthalate. 4. Optical transmission element according to one of the preceding Claims, characterized in that both layers (IS, AS) consist of stretched material. 5. Optical transmission element according to one of the preceding claims, characterized in that the adhesion between the inner layer (IS) and outer layer (AS) is so firm that the transmission element seen in the longitudinal direction is gastight. - 5 - VPA 81 G 6 5 O 2 DE 6. Optical transmission element according to one of the preceding Claims, characterized in that the fiber-shaped optical waveguide is held in a sealing manner by a filling compound (FM) applied inside the inner layer (IS).