EP0129372A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Improved optical fibre cable
Assignee: Imperial Chemical Industries Ltd
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Filing: 1984-06-06
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Granted: —
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Expires: 2004-06-06
Abstract
Abstract Optical fibre cables are produced containing an extruded support member ofthermotropic liquid crystalline polymer in which the extrusion conditions are used to control the thermal expansion coefficient of the support member. The support member may be extruded on to the support member. In this case extrusion conditions may be used to induce a compressive strain on the fibre which can counteract the thermal change in length of the fibre when subject to temperature variations so that a cable having an optical path length which is less sensitive to temperature variation can be produced. Support members which provide a loose fitting sleeve over the fibre can be produced by control of extrusion conditionsto have a thermal expansion coefficient of not less than -5×10 -6 /°K.
Inventors
- 👤 Ryan Timothy George
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-26 10:06
CPC Classifications
C; C03; C03C; C03C25/00; C03C25/10; C03C25/104; C03C25/106; C09; C09K; C09K19/00; C09K19/04; C09K19/38; C09K19/3833; C09K19/3838; G; G02; G02B; G02B6/00; G02B6/44; G02B6/4401; G02B6/4402; Y; Y10; Y10S; Y10S359/00; Y10S359/90; Y10T; Y10T428/00; Y10T428/29; Y10T428/2913; Y10T428/2933; Y10T428/2964; Y10T428/2967; Y10T428/2969
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
37 words
An optical fibre cable in which a thermotropic liquid crystalline polymer is used to provide a support member in the cable characterised in that said polymer is present as a coating surrounding and contacting the optical fibre.
Claim 2
Dependent Claim
37 words
An optical fibre cable in which a thermotropic liquid crystalline polymer is used to provide a support member in the cable characterised in that said polymer is present as a coating surrounding and contacting the optical fibre.
Claim 3
Dependent Claim
29 words
An optical fibre cable according to claim 1 in which the support member has a load capacity of at least 5 kg when subject to a strain of 0.2%.
Claim 4
Dependent Claim
28 words
An optical fibre cable according to claim 1 in which the support member has a linear thermal expansion coefficient of not less than -lxlO- 5 / * K.
Claim 5
Dependent Claim
51 words
An optical fibre cable in which a thermotropic liquid crystalline polymer is used to provide a support member in the cable characterised in that the support member is in the form of a sheath having a linear thermal expansion coefficient of the strength member is not less than -5×10 -6 /°K.
Claim 6
Dependent Claim
51 words
An optical fibre cable in which a thermotropic liquid crystalline polymer is used to provide a support member in the cable characterised in that the support member is in the form of a sheath having a linear thermal expansion coefficient of the strength member is not less than -5×10 -6 /°K.
Claim 7
Dependent Claim
24 words
An optical fibre cable according to either of claims 3 or 4 in which the support member has a positive linear thermal expansion coefficient.
Claim 8
Dependent Claim
34 words
An optical fibre cable according to either of claims 3 or 4 in which the linear thermal expansion coefficient of the support member closely matches the linear thermal expansion coefficient of the optical fibre.
Claim 9
Dependent Claim
29 words
An optical fibre cable according to any one of claims 4 to 6 in which the sheath has an internal diameter greater than the diameter of the optical fibre.
Claim 10
Dependent Claim
40 words
A process of forming an optical fibre cable reinforced with a support member comprisinq melt extruding an elongated tube of thermotropic, liquid crystalline polymer around an optical fibre under conditions such that the tube surrounds and contacts the optical fibre.
Claim 11
Dependent Claim
40 words
A process of forming an optical fibre cable reinforced with a support member comprisinq melt extruding an elongated tube of thermotropic, liquid crystalline polymer around an optical fibre under conditions such that the tube surrounds and contacts the optical fibre.
Claim 12
Dependent Claim
52 words
A process of extruding a hollow support member from a melt of a thermotropic liquid crystalline polymer comprising extruding the melt through a die to form an elongated, tubular member the ratio of the cross-sectional area of the die to the cross sectional area of the tubular member being less than 4:1.
Claim 13
Dependent Claim
52 words
A process of extruding a hollow support member from a melt of a thermotropic liquid crystalline polymer comprising extruding the melt through a die to form an elongated, tubular member the ratio of the cross-sectional area of the die to the cross sectional area of the tubular member being less than 4:1.
Claim 14
Dependent Claim
43 words
A process of extruding a support member according to either of claims 8 or 9 in which the draw down is controlled so as to produce a strength member having a linear thermal expansion coefficient not less than -5xlO- 6 / o K.
Claim 15
Dependent Claim
51 words
A process of extruding a support member according to either of claims 8 or 9 in which the draw down is controlled so as to produce a strength member having a linear thermal expansion coefficient which closely matches that of the optical fibre selected for use in the optical fibre cable.
Claim 16
Dependent Claim
50 words
A process of forming an optical fibre cable according to claim 8 in which the compressive strain induced on the optical fibre from extruding the thermotropic fibre around the fibre is controlled by means of the extrusion conditions to counteract dimensional changes in the optical fibre resulting from temperature variations.
Claim 17
Dependent Claim
40 words
A process of forming an optical fibre cable according to claim 12 wherein the thermal expansion coefficient of the thermotropic coating is less than that of the optical fibre so that a compressive strain is induced on the optical fibre.
Claim 18
Dependent Claim
33 words
A process of forming a support member according to any one of claims 8 to 12 in which the member formed by extrusion is annealed below the melting point of the thermotropic polymer.
References Cited (Backward Citations)
No citation records indexed.
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