Optical waveguides – Optical fiber bundle
Reexamination Certificate
1999-10-19
2001-08-14
Spyrou, Cassandra (Department: 2872)
Optical waveguides
Optical fiber bundle
C385S089000, C385S136000, C385S137000
Reexamination Certificate
active
06275635
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a holder for holding the ends of optical fibers constituting a bundle and for enabling them to be connected to a light-emitting device.
2. Description of Related Art
Some of the currently known holders have a body in the form of a cap, in the closed end of which an opening is formed for the introduction of the end of the fibers into its interior.
The diameter of the opening depends on the number of fibers constituting the bundle and therefore it has to be formed “in situ” by the fitter himself or at the factory.
In that type of holder, the optical fibers are held inside the cap by filling the space between the bundle formed by the optical fibers and the inner surface of the cap with an epoxy resin.
The holder is connected to the outlet of the light-emitting device by pressing, the holder being kept in the connection position owing to the friction between its outer surface and the wall of the outlet.
Those holders have a number of problems among which the following should be pointed out:
the drilling of the cap by the operator involves an increase in the time necessary for setting up the installation and therefore an increase in the cost thereof, especially if it is borne in mind that an installation may include a large number of holders;
given that the application of epoxy resin in the mentioned region does not provide for any clamping of the optical fibers forming the bundle, those optical fibers which are positioned in cavities defined by adjacent optical fibers may come free from the holder, especially when the bundle includes fibers having different diameters and different degrees of hardness;
at its rear end, the holder defines a rigid outlet and therefore, if the fibers have to change direction abruptly, some of them may be flattened or come free as mentioned above;
when the holder is connected to the outlet of the light-emitting device by pressing, the end fibers may be spaced to a greater or lesser extent from the light source in a random manner, which involves an uncontrolled variation in the efficiency of the installation.
Others of the mentioned holders are composed of a packing gland which, when tightened, brings about the deformation of a gasket having the task of exerting pressure on the optical fibers forming the bundle. Such holders have an advantage over the previous ones since they prevent the accidental release of the optical fibers; however, they have no means of solving the remainder of the problems posed above.
SUMMARY OF THE INVENTION
The holder forming the subject-matter of the present invention was devised in order to solve the problems discussed and comprises a main body having a tubular configuration, a filter-carrying ring, a sealing gasket, an element for clamping the gasket to be used, a flexible sleeve and a rear outlet mouth.
The main body has, on the inside, a frustoconical front portion for positioning the chosen gasket, a threaded intermediate portion for mounting the element for clamping the gasket and a rear member or portion for holding the front end of the sleeve once pressed into the rear portion.
The main body has, on the outside, a threaded front portion for mounting the filter-carrying ring and an intermediate portion provided with a plurality of peripheral mutually spaced and parallel channels; the purpose of the channels is to enable retractable stops provided in the outlet of the light-emitting device to be locked in any one of them; thus, the holder is prevented from being accidentally released from the light-emitting device, although it can be introduced to a greater or lesser extent into the outlet of the emitter in order to achieve adjustable control of the efficiency of the installation.
Those channels define, in the main body, a number of ribs facilitating the dissipation of heat. In order to facilitate heat dissipation, it has been provided that the main body, the clamping element, the filter-carrying ring and the split rings are produced from a material having a high thermal conductivity and sufficient strength, for example aluminium.
The filter-carrying ring, which is screwed onto the front end of the main body. defines, on the inside, a stepped configuration which enables various filters to be mounted, and, at the front, an opening for the entry of the light coming from the emitter device towards the optical fibers, passing through the mentioned filters beforehand.
In accordance with the invention, the filters to be used are preferably an infrared interference filter, or a fine-layered dichroic filter, and a filter for absorbing ultraviolet rays; optionally, a thinner, third filter of gelatin may be positioned between them in order to change the color temperature.
As mentioned above, the holder includes a sealing gasket which may comprise a set of split rings, each of which is formed by two or more portions.
All of the rings have, on the outside, a frustoconical surface having an inclination equal to that defined in the main body; however, their inside diameters are different; that feature enables the same holder to be used for bundles having a larger or smaller number of optical fibers and therefore different diameters, it merely being necessary to mount in the holder the split ring whose nominal inside diameter is the one immediately larger than that of the fiber bundle.
The element for clamping the selected ring has a tubular configuration in order to permit the passage of the bundle through its interior and is provided with a threaded portion enabling it to be mounted in the main body.
The advance of the clamping element on the main body causes the portions constituting the split ring to be displaced on the frustoconical portion of the main body, thus causing them to approach one another diametrically and causing the optical fibers forming the bundle to be trapped, thus preventing them from being released.
The gasket may also be constituted by a special form of silicone coil which can be fitted in the inner conical region of the body and on which pressure is exerted by a steel washer, preferably a nickel-plated steel washer, having a central drilled hole with a diameter suitable for the passage of the optical fiber cable.
The nickel-plated steel washers have inside diameters which are variable within a mounting set and which enable the most suitable washer to be used in each case. In a preferred example, the diameters of the washers are 15, 25 and 35 mm.
The profiled section in the form of a silicone strip constitutes a continuous tape of relatively small width, for example 15 mm, which has self-centring characteristics, and its fitting, with a variable number of turns, permits the clamping of any optical fiber cable having a diameter of from 3 to 35 mm. As a mounting unit with the holder, the silicone profiled section is given a suitable length, for example 60 cm, in order to enable it to be adapted for the purpose of obtaining the appropriate holder for the smallest size of optical fiber cable for which the holder is intended. The length of the strip or profiled section of silicone is variable in accordance with the diameter of the optical fiber cable to which the holder is fitted.
The rear region of the clamping element has diametrically opposed openings for the eventual positioning of a through-rod which facilitates its manual operation during mounting or dismounting with respect to the main body.
In accordance with the invention, the purpose of the flexible sleeve which is to be fitted to the rear region of the main body is to prevent damage to the fibers constituting the bundle if the bundle has to change direction at the outlet of the holder.
The rear mouth of the holder is composed of an annular member which has, on the inside, a toothed portion for holding the rear end of the flexible sleeve and a frustoconical surface having a diameter which increases towards its rear region in order to facilitate the introduction of the fibers of the bundle into the holder and to prevent their accelerated deterioration once secured.
RE
Advanced Fiber Optics S.L.
Cherry Euncha
Darby & Darby
Spyrou Cassandra
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