LIGHTING MODULE FOR AN AUTOMOTIVE HEADLAMP

Abstract

 The invention provides a lighting module (1) for an automotive headlamp, the lighting module comprising a low beam structure and a high beam structure, each of them comprising a housing (21, 31), a laser light source (23, 33) inside the housing, a phosphor element (24, 34) and an optical element (25, 35). These elements are adapted to provide a primary high beam and a primary low beam. The lighting module further comprises a diaphragm element (4) with a front edge (41) and an optical element (5), suitable for projecting a high beam pattern and projecting a low beam pattern.

Description

TECHNICAL FIELD

[0001] The present invention belongs to the field of lamps for automotive vehicles, and more specifically, to the lamps using laser diodes as a light source.

STATE OF THE ART

[0002] Light emitting diodes (LEDs) and laser diodes have been intended to provide lighting functions in automotive headlamps since several years ago. In fact, the former have been incorporated into road cars which are currently seen in our streets.

[0003] Regarding laser diodes, documents US 2013/058114 and US 2013/271947 describe some lighting devices with a laser diode as light source, phosphors and reflecting elements

[0004] However, the systems proposed in those documents are not capable of providing lighting functions such as high beam and low beam complying with the legal requirements.

DESCRIPTION OF THE INVENTION

[0005] The invention provides a solution for taking advantage of laser sources to provide high-beam and low-beam functions in a single light module according to claim 1. Preferred embodiments of the invention are defined in dependent claims.

[0006] In an inventive aspect, the invention provides a lighting module for an automotive headlamp, the lighting module comprising

a low beam housing comprising a low beam window opening, the low beam housing being opaque such that the low beam window opening is the only zone where light may exit from inside the low beam housing;

a low beam laser light source arranged inside the low beam housing and adapted for emitting a low laser beam, the low beam laser light source being oriented so that at least part of the low laser beam is directed to the low beam window opening;

a low beam phosphor element, arranged to receive at least part of the low laser beam, the low beam phosphor element being suitable for transforming the low laser beam into a primary low beam;

a low beam optical element arranged for receiving the primary low beam and projecting a secondary low beam;

a high beam housing comprising a high beam window opening, the high beam housing being opaque such that the high beam window opening is the only zone where light may exit from inside the high beam housing;

a high beam laser light source arranged inside the high beam housing and adapted for emitting a high laser beam, the high beam laser light source being oriented so that at least part of the high laser beam is directed to the high beam window opening;

a high beam phosphor element, arranged to receive at least part of the high laser beam, the high beam phosphor element being suitable for transforming the high laser beam into a primary high beam;

a high beam optical element arranged for receiving the primary high beam and projecting a secondary high beam;

a diaphragm element with a front edge, the diaphragm element being arranged for receiving at least part of the secondary low beam, in such a way that when the secondary low beam is projected by the low beam optical element, part of the secondary low beam is reflected by the diaphragm element;

an optical element, suitable for receiving the secondary high beam and projecting a high beam pattern and suitable for receiving a part of the secondary low beam which has not been reflected by the diaphragm element and projecting a low beam pattern, wherein secondary low beam rays corresponding to the front edge are projected as a cut-off line of the low beam pattern.

[0007] The secondary low beam rays corresponding to the front edge must be construed as the secondary low beam rays resulting from a limit angle of projection of the low beam optical element below which the secondary low beam is reflected by the diaphragm element.

[0008] The diaphragm element does not need to be an opaque element, but just adapted for reflecting at least part of the secondary low beam (such as a transparent element intended for reflecting light by total internal reflection).

[0009] This lighting module provides a way of incorporating laser light sources for performing two different functions in an automotive lighting element. These laser light sources have proved to be more efficient, provide higher luminance and lower size than any other light sources, including solid state lighting emitting devices, such as LEDs.

[0010] In some particular embodiments, the low beam phosphor element totally covers the low beam window opening and the high beam phosphor element totally covers the high beam window opening.

[0011] This arrangement of the low beam and high beam phosphor elements allows the lighting module to be more reliable regarding the conversion of the source high and low laser light beams.

[0012] In some particular embodiments, the low beam optical element is located outside the low beam housing and the high beam optical element is located outside the high beam housing.

[0013] This arrangement of the low beam and high beam optical elements allows the lighting module to be more versatile, since the optical element may be arranged in a greater number of locations thus adapting to the other components of the module.

[0014] In some particular embodiments, the lighting module a further comprises a low beam heat sink arranged in thermal contact with the low beam laser light source and a high beam heat sink arranged in thermal contact with high beam laser light source.

[0015] The thermal contact between the light source and the heat sink should be understood in the sense that such a lighting module enables heat transfer between the light source and the heat sink, either by direct contact or by means of an intermediate element. This thermal contact may be embodied in some different ways. In some embodiments, the lighting module electronic assembly would comprise a plastics substrate with a conductive track directly deposited on it and the light source being placed in direct contact with the heat sink but electrically connected to the conductive track.

[0016] In some particular embodiments, at least one of the low beam and high beam heat sinks is made of aluminium, an aluminium alloy or a thermal conductive plastic.

[0017] This material is advantageously used because of its lightness, low price, ease of manufacturing and heat dissipation properties.

[0018] In some particular embodiments, the lighting module further comprises a main heat sink, which is arranged in thermal contact with both the low beam housing and with the high beam housing.

[0019] A main heat sink helps to improve the global heat dissipation of the module, since laser light sources have severe restrictions regarding heat dissipation and operation conditions.

[0020] In some particular embodiments, at least one of the low beam optical element and high beam optical element is a collimator.

[0021] A collimator provides an optimal optical behaviour for this application. The collimator is able to transform the divergent beams of light coming from a unique light source into a parallel distribution of light beams.

[0022] In some particular embodiments, the diaphragm element is an opaque folder. Alternatively, the diaphragm element is an element having a transparent surface, such as light guide, the transparent surface playing the role of diaphragm falling back on the principle of total internal reflection.

[0023] Another inventive aspect of this invention provides an automotive headlamp comprising a lighting module according to the previous inventive aspect.

[0024] In some particular embodiments, the automotive lighting device further comprises a housing accommodating the lighting module and auxiliary systems.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] To complete the description and in order to provide for a better understanding of the invention, a set of drawings is provided. Said drawings form an integral part of the description and illustrate an embodiment of the invention, which should not be interpreted as restricting the scope of the invention, but just as an example of how the invention can be carried out. The drawings comprise the following figures:

Figure 1 shows a side cut section of a particular embodiment of an automotive lighting module according to the invention.

Figure 2 shows an automotive headlamp comprising the lighting module described in the previous figure.

DETAILED DESCRIPTION OF THE INVENTION

[0026] Figure 1 shows a side cut section of a particular embodiment of an automotive lighting module according to the invention.

[0027] In this figure, the lighting module 1 comprises the following elements

a low beam housing 21 comprising a low beam window opening 22, the low beam housing 21 being opaque such that the low beam window opening 22 is the only zone where light may exit from inside the low beam housing 21;

a low beam laser light source 23 arranged inside the low beam housing 21 and adapted for emitting a low laser beam, the low beam laser light source 23 being oriented so that the low laser beam is directed to the low beam window opening 22;

a low beam phosphor element 24, arranged to receive the low laser beam, the low beam phosphor element 24 being suitable for transforming the low laser beam into a primary low beam;

a low beam optical element 25 arranged for receiving the primary low beam and projecting a secondary low beam;

a high beam housing 31 comprising a high beam window opening 32, the high beam housing 31 being opaque such that the high beam window opening 32 is the only zone where light may exit from inside the high beam housing 31;

a high beam laser light source 33 arranged inside the high beam housing 31 and adapted for emitting a high laser beam, the high beam laser light source 33 being oriented so that the high laser beam is directed to the high beam window opening 33;

a high beam phosphor element 34, arranged to receive the high laser beam, the high beam phosphor element 34 being suitable for transforming the high laser beam into a primary high beam; and

a high beam optical element 35 arranged for receiving the primary high beam and projecting a secondary high beam.

[0028] This arrangement provides a device which is suitable for emitting a primary high beam and a primary low beam. But these primary light beams need to be modulated by further parts before becoming high and low beams complying with automotive regulations.

[0029] The lighting module further comprises a diaphragm element 4 with a front edge 41. This diaphragm element 4 is arranged for receiving at least part of the secondary low beam, in such a way that when the secondary low beam is projected by the low beam optical element 25, part of the secondary low beam is reflected by the diaphragm element 4.

[0030] Further, the lighting module also comprises an optical element 5, such as an outer lens, suitable for receiving the secondary high beam and projecting a high beam pattern and suitable for receiving the part of the secondary low beam which has not been reflected by the diaphragm element 4 and projecting a low beam pattern, wherein the part of the secondary low beam corresponding to the front edge 41 is projected as a cut-off line of the low beam pattern.

[0031] As a consequence, regulated low beam and high beam may be obtained in such a lighting module.

[0032] The low beam phosphor element 24 and the high beam phosphor element 34 totally cover the low beam window opening 22 and the high beam window opening 32 respectively, so that no laser light exits the low beam housing 21 and the high beam housing 31 which has not passed through these phosphor elements 24, 34.

[0033] In the embodiment shown in this figure, the low beam optical element 25 is located outside the low beam housing 21 and the high beam optical element 35 is located outside the high beam housing 31. Hence, the low beam housing 21 and the high beam housing 31 do not need to be very bulky, and the phosphor elements do not need to be very big either, since they may be placed closer to the laser light sources.

[0034] Heat dissipation is an important problem when dealing with laser light sources. As a consequence, the lighting module shown in this figure comprises individual heat sinks and a global heat sink.

[0035] A low beam heat sink 26 is arranged in thermal contact with the low beam laser light source 23 and a high beam heat sink 36 is arranged in thermal contact with high beam laser light source 33. These individual heat sinks directly manage the heat produced by the laser light sources and conduct it outside the low beam housing 21 and the high beam housing 31.

[0036] In different embodiments, these low beam and high beam heat sinks 26, 36 are made of aluminium, an aluminium alloy or a thermal conductive plastic.

[0037] This lighting module further comprises a main heat sink 6, which is arranged in thermal contact with both the low beam housing 21 and with the high beam housing 31.

[0038] This main heat sink helps the lighting module to dissipate all the heat produced by the laser light sources.

[0039] Figure 2 shows an automotive headlamp 10 comprising the lighting module 1 described in the previous figure.

Claims

1. A lighting module (1) for an automotive headlamp, the lighting module comprising

a low beam housing (21) comprising a low beam window opening (22), the low beam housing (21) being opaque such that the low beam window opening (22) is the only zone where light may exit from inside the low beam housing (21);

a low beam laser light source (23) arranged inside the low beam housing (21) and adapted for emitting a low laser beam, the low beam laser light source (23) being oriented so that at least part of the low laser beam is directed to the low beam window opening (22);

a low beam phosphor element (24), arranged to receive at least part of the low laser beam, the low beam phosphor element (24) being suitable for transforming the low laser beam into a primary low beam;

a low beam optical element (25) arranged for receiving the primary low beam and projecting a secondary low beam;

a high beam housing (31) comprising a high beam window opening (32), the high beam housing (31) being opaque such that the high beam window opening (32) is the only zone where light may exit from inside the high beam housing (31);

a high beam laser light source (33) arranged inside the high beam housing (31) and adapted for emitting a high laser beam, the high beam laser light source (33) being oriented so that at least part of the high laser beam is directed to the high beam window opening (33);

a high beam phosphor element (34), arranged to receive at least part of the high laser beam, the high beam phosphor element (34) being suitable for transforming the high laser beam into a primary high beam;

a high beam optical element (35) arranged for receiving the primary high beam and projecting a secondary high beam;

a diaphragm element (4) with a front edge (41), the diaphragm element (4) being arranged for receiving at least part of the secondary low beam, in such a way that when the secondary low beam is projected by the low beam optical element (35), part of the secondary low beam is reflected by the diaphragm element (4);

an optical element (5), suitable for receiving the secondary high beam and projecting a high beam pattern and suitable for receiving a part of the secondary low beam which has not been reflected by the diaphragm element (4) and projecting a low beam pattern, wherein secondary low beam rays corresponding to the front edge (41) are projected as a cut-off line of the low beam pattern.

2. A lighting module according to claim 1, wherein the low beam phosphor element (24) totally covers the low beam window opening (22) and the high beam phosphor element (34) totally covers the high beam window opening (32).

3. A lighting module according to any of claims 1 or 2, wherein the low beam optical element (25) is located outside the low beam housing (21) and the high beam optical element (35) is located outside the high beam housing (31).

4. A lighting module according to any of the preceding claims, wherein the optical element (5) is an outer lens.

5. A lighting module according to any of the preceding claims, further comprising a low beam heat sink (26) arranged in thermal contact with the low beam laser light source (23) and a high beam heat sink (36) arranged in thermal contact with high beam laser light source (33).

6. A lighting module according to claim 5, wherein at least one of the low beam and high beam heat sinks (26, 36) is made of aluminium, an aluminium alloy or a thermal conductive plastic.

7. A lighting module according to any of claims 5 or 6, further comprising a main heat sink (6), which is arranged in thermal contact with both the low beam housing (21) and with the high beam housing (31).

8. A lighting module according to any of the preceding claims, wherein at least one of the low beam optical element (25) and high beam optical element (35) is a collimator.

9. A lighting module according to any of the preceding claims, wherein the diaphragm element (4) is an opaque folder or an optical element having a transparent surface.

10. An automotive headlamp comprising a lighting module according to any of the preceding claims.

Drawing