WO2009081332A1

WO2009081332A1 - Lamp for feeding a light guide or guides

Info

Publication number: WO2009081332A1
Application number: PCT/IB2008/055345
Authority: WO
Inventors: Sven Schellinger; Albrecht Kraus
Original assignee: Philips Intellectual Property & Standards Gmbh; Koninlijke Philips Electronics N.V.
Priority date: 2007-12-21
Filing date: 2008-12-16
Publication date: 2009-07-02

Abstract

The invention relates to a lamp comprising a base that carries at least one envelope in which a light source is arranged, means being provided for directed coupling-in for at least one light guide (5).

Description

LAMP FOR FEEDING A LIGHT GUIDE OR GUIDES

The invention relates to a lamp, particularly for motor vehicles, comprising a base carrying an envelope in which a light source is arranged.

In the field of motor vehicle lighting, increasing use is being made of light guides, which are employed as, amongst other things, side lights or as features of the design or styling. In this way, light guides are for example arranged in a circle around headlamps to emphasize the outline shape of the latter. Another suitable application is as the light guides that are increasingly being used in various countries to perform the function of daytime running lights.

Light guides of this kind are fed by lamps that are positioned at one end of the light guide. A problem that arises in this case is that only a small proportion of the light emitted by the lamp actually enters the light guide that is being fed, for which reason high-powered lamps are required. On the one hand lamps of this kind have a high energy consumption and on the other hand their working life is very limited.

It is for these problems that the invention aims to provide a remedy. An object underlying the invention is to provide a lamp that enables a light guide to be fed in a more efficient manner. In accordance with the invention, this object is achieved by providing means for directed coupling-in for at least one light guide.

The invention provides a lamp that enables a light guide to be fed in a more efficient manner.

In a further form of the invention, the lamp is a high-intensity discharge lamp, with the light source being formed by two electrodes that project into a discharge chamber of the envelope of the lamp. High-intensity discharge lamps of this kind have a high light yield and emit a very bright light.

In a further form of the invention, the means comprise a mask that is set up in such a way that substantially all the visible light emitted by the light source is directed to the at least one light guide. This causes the light to be fed into the light guide in a targeted manner. The mask is preferably a coating that has an opening at the at least one coupling-in position for the at least one light guide.

In a further form of the invention, the coating is produced in a fully reflective form. Alternatively, the coating is produced in the form of a partly reflective coating that is preferably so formed that IR radiation is not reflected but is transmitted. What is thereby achieved is that heat is dissipated in an improved way.

Advantageously, the coating is produced in the form of a partly reflective coating that is so formed that UV radiation is not reflected but is transmitted. This prevents any intensification of the UV radiation, which intensification would have an adverse effect on components made from plastics materials.

In a further form of the invention, the lamp is a high-intensity discharge lamp and the coating is applied to the envelope of the burner. This enables the emitted light to be redirected in an efficient way. Alternatively, the lamp is a high-intensity discharge lamp that has a burner envelope and an outer envelope surrounding the latter, the coating being applied to the outer envelope.

In a further form of the invention, the outer envelope of the lamp has at least one formed excrescence that projects outwards laterally. This improves the targeted feed to the light guide that is to be connected on. The outwardly projecting end of the formed excrescence is preferably of a diameter that substantially corresponds to the diameter of the light guide that is to be coupled on.

The formed excrescence is preferably designed to be fully or partly reflective in such a way that the incident light is concentrated along the center axis of the formed excrescence. The directed feed of light into the light guide is assisted by this means.

Other forms and variants of the invention are specified in the remainder of the dependent claims. Embodiments of the invention are shown in the drawings and will be described in detail below. In the drawings: Fig. 1 is a schematic view of a lamp that is coupled into light guides. Fig. 2 is a schematic view of a further embodiment of lamp having projecting formed excrescences to which light guides are coupled. Fig. 3 is a schematic view of a further embodiment of lamp that is coupled into light guides.

The lamp selected as an embodiment is in the form of a discharge lamp and comprises an outer envelope 1, in which a burner envelope 2 is arranged and which is connected to a base 4.

The high-intensity discharge lamp is shown in an approximately horizontal installed position. The lamp has a burner envelope 2 that transmits light, that is sealed off to be vacuum-tight and that is composed of quartz glass. The burner envelope 2 encloses a discharge chamber 21. The discharge chamber is filled with an ionizing mixture of gases that comprises at least one inert gas, and in particular xenon, and a mixture of metal halides. Arranged opposite one another in the usual way in the discharge chamber 21 are two electrodes 22, 23. The free distance between the two electrodes 22, 23 forms the discharge path, in the center of which the center of the discharge chamber is also situated. The electrode 22 is connected in the usual way to an electrical conductor 221; the electrode 23 is connected to an electrical conductor 231 that is connected in turn to a return pole (not shown) that runs back to the base, outside the outer envelope 1, approximately parallel to the longitudinal axis of the lamp.

Applied to the surface of the exterior of the burner envelope 2 is a coating 3 that covers the discharge chamber 21 and, on both sides of the discharge chamber 21, the burner envelope out as far as the pinches (not shown) holding the electrical conductors 221, 231. Arranged diametrically opposite one another in the coating 3, centrally to the discharge chamber 21, are two circular openings 31, an imaginary line through the centers of the openings 31 extending at a point central between the electrodes 22, 23. In the embodiment, the coating 3 is produced in the form of a partly reflective layer by which UV radiation and IR radiation are transmitted, which means that only visible light is reflected in the direction of the openings 31. Alternatively, the coating 3 may also take the form of a fully reflective layer.

In the embodiment shown in Fig. 1, the outer envelope 1 is of a largely cylindrical form. Two light guides 5 are arranged diametrically opposite one another laterally of the outer envelope 1 , in such a way that their axes of symmetry in rotation extend though the centers of the openings 31. The path following by the visible light emitted is indicated in the form of dashed lines.

In the embodiment shown in Fig. 2, two formed excrescences 11 are integrally formed on the sides of the outer envelope 1 diametrically opposite one another. The formed excrescences 11 are produced to be symmetrical in rotation, with their axes of symmetry in rotation extending through the centers of the openings 31 in the coating 3. The outside diameter of the formed excrescences 11 at their outwardly directed free ends substantially corresponds to the outside diameter of the light guides 5 that are to be coupled on. The outline shape of the formed excrescence 11 is so designed that light emerging from the opening 31 in the coating 3 is reflected in the direction of the outward- facing end of the formed excrescence 11. In addition or as an alternative, the formed excrescence 11 may be provided with a coating that causes the incident light to be redirected in the direction of the outwardly projecting end of the formed excrescence 11. In the embodiment shown in Fig. 3, the coating 3 is applied to the outer envelope 1. The outer envelope 1 has in this case, surrounding the discharge chamber 21 of the burner envelope 2, an ellipsoidal portion 12 whose longitudinal axis of symmetry in rotation extends through the centers of two openings 31 in the coating 3 that are arranged diametrically opposite one another. The light guides 5 are coupled on in such a way that their axes of symmetry in rotation lie on the longitudinal axis of symmetry in rotation of the ellipsoidal portion 12 of the outer envelope 1. There is also a reflector 41 integrally formed on the base 4. In addition to allowing the light guides 2 to be coupled in in a directed fashion, the design of the lamp shown in Fig. 3 also allows illumination to take place forwards in the direction pointing away from the base 4. A design of lamp of this kind is for example suitable as a light-guide feed that performs, in addition, a daytime running light function.

Claims

1. A lamp comprising a base that carries at least one envelope in which a light source is arranged, characterized in that means are provided for directed coupling- in to at least one light guide (5).

2. A lamp as claimed in claim 1, characterized in that the lamp is a high- intensity discharge lamp, the light source being formed by two electrodes (22, 23) that project into a discharge chamber (21) of the envelope (2).

3. A lamp as claimed in claim 1 or 2, characterized in that the means comprise a mask (3) that is set up in such a way that substantially all the visible light emitted by the light source is directed to the at least one light guide (5).

4. A lamp as claimed in claim 3, characterized in that the mask (3) is a coating that has an opening (31) at at least one coupling-in position for the at least one light guide (5).

5. A lamp as claimed in claim 4, characterized in that the coating (3) is produced in a fully reflective form.

6. A lamp as claimed in claim 4, characterized in the coating (3) is produced in the form of a partly reflective coating that is so formed that IR radiation is not reflected but is transmitted.

7. A lamp as claimed in claim 4 or 5, characterized in that the coating is produced in the form of a partly reflective coating that is so formed that UV radiation is not reflected but is transmitted.

8. A lamp as claimed in any of claims 4 to 7, characterized in that the lamp is a high-intensity discharge lamp and in that the coating (3) is applied to the envelope (2) of the burner of the high-intensity discharge lamp.

9. A lamp as claimed in any of claims 4 to 7, characterized in that the lamp is a high-intensity discharge lamp that has a burner envelope (2) and an outer envelope (1) surrounding the latter, the coating (3) being applied to the outer envelope (1).

10. A lamp as claimed in any of the foregoing claims, characterized in that the outer envelope (1) of the lamp has at least one formed excrescence (11) that projects outwards laterally.

11. A lamp as claimed in claim 10, characterized in that the outwardly projecting end of the formed excrescence is of a diameter that substantially corresponds to the diameter of the light guide (5) that is to be coupled on.

12. A lamp as claimed in either of claims 10 and 11, characterized in that the formed excrescence is designed to be fully or partly reflective in such a way that the incident light is concentrated along the center axis of the excrescence.

13. A lamp as claimed in claim 1 or 2, characterized in that the means comprise an envelope (2) that surrounds the light source and that is in the form of a reflector, thus causing substantially all the light that is emitted by the light source to be directed to the at least one light guide (5).