Coating processes – Optical element produced – Polarizer – windshield – optical fiber – projection screen – or...
Patent
1995-01-03
1996-04-09
Bell, Janyce
Coating processes
Optical element produced
Polarizer, windshield, optical fiber, projection screen, or...
118404, 118419, 118423, 118641, 427358, 4273855, 4274347, 427512, 427514, C03C 2502
Patent
active
055059880
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a method for colouring optical fibres, wherein each fibre is drawn through an upper nozzle in a colouring tool into a colour chamber, into which colorant is introduced, and further through a lower nozzle out of the colour chamber, and wherein the coloured fibre is passed onward through a quartz tube of a UV lamp curing the colorant. The invention also relates to an arrangement for colouring optical fibres.
Optical fibres are used more and more extensively in different technical fields, such as telecommunication technology. The small size and fragile structure of optical fibres, however, make them difficult to handle. Similarity in appearance of fibres also causes problems in practical applications as it is difficult to distinguish different fibres from each other without an identification system.
It is therefore a common practice to colour different fibres with different colours, and so individual fibres are easier to distinguish from each other.
At present, optical fibres are coloured e.g. by UV curable colorants. They are coloured one by one in a separate coloration process mainly comprising a colouring tool and UV lamps for curing the colorant. The colouring tool comprises successive nozzles and a colour chamber between the nozzles. The UV lamps comprise a quartz tube through which the fibre passes. The fibre to be coloured is drawn through the upper nozzle and the colour chamber and further through the lower nozzle. At the same time colorant is introduced into the colour chamber so that it adheres to the surface of the fibre. After the lower nozzle, the fibre is drawn into the quartz tube of the UV lamp so that the UV radiation generated by the lamp cures the colorant on the surface of the fibre. A separate apparatus of this kind is arranged for each fibre to be coloured.
The above-described prior art includes e.g. U.S. Pat. No. 4,629,285.
A drawback of the prior art technique is that it is expensive as the apparatus costs are very high. This is due to the fact that each fibre to be coloured needs its own separate colouring apparatus. For instance, each fibre to be coloured needs one or two expensive UV lamps, etc. A further problem is that the coloration process has been a separate process, which increases the number of work stages required in the cable production and further increases the costs.
The object of the invention is to provide a method and an arrangement by means of which the drawbacks of the prior art technique can be eliminated. This is achieved by means of the invention. The method according to the invention is characterized in that the colouring tools are arranged close to each other in pairs in at least two different planes; and that the fibres to be coloured are drawn simultaneously through the colouring tools and further simultaneously through the quartz tube of the UV lamp common to the fibres to be coloured. The arrangement according to the invention, in turn, is characterized in that the colouring tools are positioned close to each other in pairs in at least two different planes that the fibres to be coloured can be drawn simultaneously through the colouring tools and the quartz tube of the UV lamp common to the fibres to be coloured.
As compared with the prior art technique, one advantage of the invention is that the coloration process can be made part of e.g. the subsequent stage of the cable production process in a simple way so that the separate fibre colouring stage is eliminated. This allows considerable savings to be achieved in storage and handling costs. Another advantage is that the number of expensive UV lamps is reduced as compared with the prior art technique. The coloration of four fibres requires eight UV lamps in the prior art technique while only two UV lamps are required when applying the invention in a corresponding case, which is a major difference. Still another advantage of the invention is that the total production capacity is increased as compared with the prior art.
BRIEF DESCRIPTION OF THE DRAWINGS
In the following the inventio
REFERENCES:
patent: 5294260 (1994-03-01), Larsen-Moss
patent: 5330786 (1994-07-01), Nonaka et al.
patent: 5334421 (1994-08-01), McNutt
Peltoluhta Erkki
Tanskanen Juha
Bell Janyce
Nokia-Maillefer Oy
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