Device for optical fibers illumination

The present invention relates to improvements to devices for illuminating the optical fibers commonly referred to as "light generating" or "light sources".

A light source generally comprises an illuminating lamp and an optical device to focus the light rays onto the end of fiber optic bundle, the source also comprises a transformer if a low-voltage lamp is used. All these elements are enclosed in a closed housing.

The temperature increase inside the housing is unacceptable because the destruction of the fiber is to be feared. Therefore, it is necessary to ventilate, but the air circulating inside the vehicle housing dust that settle with all the inconvenience this may present.

The present invention which overcomes these disadvantages, is characterized in that the light rays pass through an enclosure, dustproof at least consisting of a straight prism with triangular base each of the faces of this prism having an opening closed by the respectively front face of the usual lamp, a mirror and a lens which converges the beam at the end of the fiber bundle, said end being held outside the enclosure.

The mirror used is of the kind that can be traversed by infrared radiation. In this way, part of the heat, that reflected from the projector lamp and the lamp itself is out of the enclosure, through the mirror, without reaching the beam. A device comprising a prism and a mirror as described in WO 97/10471. The other part is radiated from the outer face of the projector and the lamp cap which, according to the invention are located outside the enclosure.

The invention will be better understood by the following description with reference to the accompanying drawings by way of indication only, in which:<ul><li>Figure 1 is a perspective view showing the shape of the support housing of the optical members;</li><li>Figure 2 is a vertical sectional view of a source according to the invention.</li></ul>

According to the invention, the bodies necessary to clarify, in good conditions, the end of a bundle of optical fibers 1, are carried by a housing 2 having the shape of a triangular prism.

Each of the side faces 3, 4 and 5 of the housing has an opening respectively 6, 7 and 8. The surfaces 3 and 5 are disposed at right angles.

The opening 6 is closed by the front face of the reflector 9 in the usual lamp, said reflector and its base 10 being located outside the casing 2.

The opening 7 is closed by a mirror 11, of a known type, of the type having the property of being traversed by the infrared rays.

The opening 8 is closed by a lens 12 focusing the light rays, reflected by the mirror 11, on the end 1a of the beam 1.

Hot rays reflected by the reflector of the lamp, pass freely through the mirror 11 and can not reach the end 1a of the beam.

By the provision of the lamp relative to the housing, the part of the heat radiated by the outer surface of said lamp is dissipated to the ambient air.

The lamps used are mass produced and their characteristics are sometimes uncertain. Therefore, it is possible that some hot rays do not meet the mirror 11 and pass through the lens 12. According to the invention, they are cooled in the space 13 formed between the outer wall of the housing and the end 1a of the beam.

We also know, for the reasons mentioned above, a portion of the light energy emitted by the lamp does not meet the mirror 11 or, in the known devices, is not returned to the lens 12.

According to another characteristic of the invention, which overcomes this disadvantage, all the internal surfaces of the housing are reflective.

As is apparent from Figure 2, the housing 2 is sealed against dust at least. The sealing can be achieved using joints (not shown) maintaining the members 9 and 12 being insured by circlips 14. As regards the mirror 11, it can be maintained by bonding.

Triangular bases 15 can be molded with the faces 3 and 5 or be carried by the face 4.

For reasons of mechanical protection, the assembly which has just been written above is held in a casing (not shown) made, for example, perforated sheet. This envelope can advantageously withstand the usual power supply (when using a low voltage lamp) and, or, a color change mechanism.