EP3371509A1

EP3371509A1 - Light module

Info

Publication number: EP3371509A1
Application number: EP16790975.3A
Authority: EP
Inventors: Ernst-Olaf Rosenhahn; Christian Buchberger; Martin Licht; Joachim Knittel
Original assignee: Automotive Lighting Reutlingen GmbH
Current assignee: Marelli Automotive Lighting Reutlingen Germany GmbH
Priority date: 2015-11-02
Filing date: 2016-11-02
Publication date: 2018-09-12
Anticipated expiration: 2036-11-02
Also published as: EP3371509B1; WO2017076870A1; DE102015221399A1

Abstract

The invention relates to a light module (10) for a headlamp of a motor vehicle, comprising at least one laser light source (12) for radiating a primary beam of light (14), a wavelength converter (20) for converting the primary beam of light (4) into a secondary light pattern (24), and an optical radiation device (26) for rearranging the secondary light pattern (24) into a radiation light pattern (28) of the light module (10). The laser light source (12) is designed such that the primary beam of light (14) is radiated in a primary solid angle region around a primary radiation direction (16), and such that the wavelength converter (20) is designed in such a way that the primary beam of light (14) is incident on the wavelength converter (20) in the primary solid angle region around the primary radiation direction (16), and such that a carrier component (22) is provided to hold the wavelength converter (20) and that the carrier component (22) comprises a safety guard (32) which, viewed from the wavelength converter (20), covers the primary solid angle region around the primary radiation direction (16).

Description

light module

description

The invention relates to a light module for a motor vehicle headlamp according to the preamble of claim 1.

In the field of automotive lighting, especially for car headlamps, the use of powerful

Light sources with the highest possible luminance desired.

As a result, can be bright with a small space

Realize lighting equipment. The radiated

Light distributions must have certain, usually prescribed by law properties. For the headlights of a motor vehicle usually white light is desired.

With laser light sources, such as semiconductor laser diodes, high radiation power can be

achieve. However, laser light sources generally emit almost monochromatic, coherent and highly collimated laser light, which in this form does not emanate directly as radiated light

Lighting device can be used. Laser light sources are therefore usually used in automotive lighting with a wavelength converter. The monochromatic, coherent laser light is converted into diffused and largely incoherent white light. From DE 10 2012 220 481 AI and US 8,400,011 B2 are

For example, light modules with a laser light source and a photoluminescence converter known. Of the

Photoluminescence converter has a

Photoluminescent on which by excitation to

Photoluminescence by means of laser light emits light with different wavelengths. The thus achieved

Secondary light distribution includes the converted light and possibly also scattered portions of the incident light, and is therefore useful for the purposes of automotive lighting.

The wavelength converter has a safety-relevant significance, since unconverted laser light is potentially dangerous in the typical high radiation power of laser light sources.

If the wavelength converter is damaged, can

Circumstances a danger from the

Lighting device emerging, strongly collimated laser beams occur. In order to detect damage to the converter and, if appropriate, to switch off the laser, DE 10 2012 220 481 A1 and US Pat. No. 8,400,011 B2 have a detection device for detecting the

Radiation intensity is provided. Disadvantages of this

Safety devices are extra

optical and electronic components need to detect the radiation intensity. In addition, a controller is required to turn off the laser light source when the detected intensity

Safety limit exceeds. From DE 10 2012 220 472 AI is a

Safety device known in which a diaphragm is arranged on a radiating device or in the beam path between the photoluminescent element and the abstract optics. This bezel must be precise in terms of the

Photoluminescent element and the laser light source are adjusted. In addition, it must be ensured constructively that the aperture does not unintentionally change its position.

A lighting device with the features of the preamble of claim 1 is described in WO 2015/154983 AI. Here, a wavelength converter is provided with a hole through which a direct light component of the

Primary light beam is irradiated.

The present invention has for its object to reliably and sturdy way to avoid exposure to leaking laser light from a motor vehicle lighting device.

This object is achieved by a light module having the features of claim 1. In the present context, a light module is understood to mean the actually light-emitting structural unit of a motor vehicle lighting device. However, the task is also served by a motor vehicle

Lighting device solved with the features of the described light module. The light module comprises a laser light source for

Transmission of a primary light beam into a

Primary space angle range around a Primärärabstrahlrichtung starting from the laser light source. Further, a

Wavelength converter provided, which is arranged such that the ausstrahlbare with the laser light source Primary light beam impinges on the wavelength converter. The wavelength converter is designed such that by the impinging primary light beam a

Secondary light distribution with particular polychromatic or white light can be emitted by at least a portion of the primary light beam of laser light, e.g. is converted by using photoluminescence in light of different wavelength. The secondary light distribution is in particular in one

Secondary space angle range emitted. The emission of the secondary light distribution from the wavelength converter is particularly diffuse and largely undirected. As a rule, the wavelength converter, after excitation by the primary light beam, has the emission characteristic of a Lambert radiator. The secondary space angle range is far greater than that

Primary space angle range. The light module further comprises an abstraction means (e.g., projection lens, deflection reflector) for transforming the secondary light distribution into an emission light distribution of the light module. The emission light distribution is e.g. concentrated around a main emission direction, which when installed in a motor vehicle e.g. pointing in the direction of travel.

The light module also includes a support member for

Holding the wavelength converter. The support member has a safety bar, which, starting from the

Wavelength converter looks at that

The primary space angle area is covered around the primary ejection direction.

In trouble-free normal operation results in the

Light module following beam path: Starting from the as Primary light source acting laser light source extends a primary light beam (laser light) substantially in the

Primary space angle around the primary radiation direction. The emitted from the laser light source

Primary light bundle usually hits the

Wavelength converter. The wavelength converter converts the coherent primary light beam into a usable one

Secondary light distribution from diffuse largely

incoherent white light around. The light rays of the

Secondary light distribution hit the

Abstrahloptikeinrichtung and are of this in the, preferably substantially concentrated around a main emission direction of the light module, Abstrahllichtverteilung transformed (i.e., deflected and / or reflected and / or projected). For the Abstrahloptikeinrichtung therefore the wavelength converter acts as the actual light source whose secondary light distribution is no longer substantially the risk potential of laser light. in the

Normal operation, the wavelength converter thus ensures that the potentially dangerous laser light does not enter directly into the Abstrahllichtverteilung.

Is the wavelength converter, for example due to mechanical influences, an accident or

Design error not in the beam path of the

Primary light beam arranged (for example, broken), the laser light of the primary light beam through the on

Carrier component of the wavelength converter arranged

Safety bar suppressed. The safety bar is thus arranged on the support member that prevents, despite the no longer effective

Wavelength converter potentially dangerous laser light exits the light module. The safety bar

also ensures that the wavelength converter is protected against mechanical influences on the carrier component is arranged.

When using laser light sources, due to the typically highly collimated light beam with a small beam diameter, a precise alignment of the

Laser light source on the wavelength converter and a reliable and safe arrangement of the

Wavelength converters are ensured. This can be ensured with the carrier component for holding the wavelength converter and possibly its manner of attachment in the light module.

By arranging the safety bracket on the support member of the wavelength converter is the

Safety bar also in a robust, safe and precisely aligned to the laser light source position. In the embodiment according to the invention can thus each laser beam through the safety bar inside the

Light module to be stopped. In case of failure, a danger is radiated in an easy-to-implement manner

Laser beams avoided. This protective device has a high level of reliability, since in particular movable mechanical components or electronic controls are not required.

The Abstrahloptikeinrichtung can be used as a reflector, for.

parabolic reflector or as reflector arrangement

be educated. It is also possible that the

Abstrahloptikeinrichtung as a projection device, e.g. comprising a projection lens is formed. The

Abstrahloptikeinrichtung can also consist of several

Optic elements exist, e.g. Primary optics and

Secondary optics. In trouble-free normal operation, the influence of the Safety bar on the emission light distribution

negligible. This is due to the fact that the safety bar is preferably dimensioned in size such that the light is blocked only in the case where it is directly (without

Wavelength converter) hits the safety bar. For typical laser light sources, the half-power angle of the laser light may be about 2 ° -8 °. The safety bar has e.g. a length of 10mm to 20mm and a

Transverse extension of 1mm to 8mm and can block in the said case, for example, 90% of the laser beam. If the wavelength converter is effective, the

Abstrahllichtverteilung essentially by the of

Wavelength converter radiated secondary light distribution fed. The largely incoherent white light of the

Secondary light distribution is less collimated and more diffuse. The power of the secondary light distribution is therefore more homogeneous in the space in the secondary space angle range

distributed. The secondary space angle range is significantly larger than the primary space angle range. A suppression of light rays through the safety bar in the

Therefore, in normal operation, a comparatively small primary space angle range about the primary radiation direction does not lead to a significant loss of power or disturbances in the emission light distribution. To power losses too

In particular, the safety bar is designed to be no larger than to block the

Primary beam required. The safety bar is particularly dimensioned such that only light is blocked, which is around the Primärärabstrahlrichtung in the

Primary space angle area running on the safety bar meets.

Preferably, the safety bar is firmly connected to the carrier component, in particular integrally connected. Thereby the safety bar is mechanically robust and strong

adjusted integrated into the carrier component. In particular, this ensures that the safety bar is aligned relative to the wavelength converter exactly.

Preferably, the safety bar in the beam path of the primary light beam between wavelength converter and

Abstrahloptikeinrichtung arranged. This will do that

Primary light bundle is suppressed by the safety bar before it hits the Abstrahloptikeinrichtung and prevents from the outset that potentially dangerous

Laser light is deflected by the Abstrahloptikeinrichtung in the direction of the Abstrahllichtverteilung. In particular, the safety bar protrudes beyond a mounting plane of the

Wavelength converter, in which the

Wavelength converter is arranged out.

In a preferred embodiment, the

Safety bracket in its further course spaced from the mounting plane and extends along the

Mounting plane, in particular substantially parallel to the mounting plane. The distance of the along the

Mounting level extending portion of the

Safety bracket from the mounting plane can be for example about 1 - 10 mm. It is conceivable that the

Safety bracket starting from the mounting plane initially has an oblique course. After the oblique course of the safety bar can pass into a section with a parallel course to the holding plane. It is also conceivable that the safety bar along its extension a

has angled course. In particular, the

Safety bar finger-like configured and extends kinked over the mounting plane. By the

Angled design impairs the

Safety bar with intact wavelength converter one the smallest possible area of the secondary light distribution.

Preferably, the safety bar comprises on the

Laser light source facing side one

Absorption region, which is designed such that incident laser light is at least partially absorbable. This can be done by the

Absorption region comprises a trained for the absorption of laser light surface.

It proves to be advantageous if the absorption region is formed on the side facing the laser light source only in the region which covers the primary space angle range.

According to one embodiment of the invention, comprises

Safety bar a scattering area with a surface of a scattering material, so that an incident light beam in particular such as to the side or diffused, that it is not of the

Abstrahloptikeinrichtung is detected. One on the

The scattering surface incident light bundle thereby does not contribute to the emission of light distribution. Also conceivable is an embodiment, according to which the

Safety bar a reflection area with a

Reflection surface comprises, which is arranged such that a incident along the primary beam direction of light beam is deflected so that it is not for

Contributes emission light distribution. One on the

Reflecting surface incident light beam is

especially distracted so that it is not from the

Abstrahloptikeinrichtung is detected. For example, the reflection surface may be oriented obliquely to the primary radiation direction. An advantageous embodiment results from the fact that the safety bar comprises a rear reflection area with a reflecting surface, so that a light bundle which strikes the reflecting surface running along the direction of the primary radiation back to the

Wavelength converter is directed. The light beam can then be scattered by the wavelength converter and thus contribute at least partially to the emission light distribution. The back reflection area can be e.g. so

be designed and oriented to reflect a reflected light compared to the original one

Beam direction remote or marginal area of the wavelength converter meets. In a partially damaged wavelength converter can thereby the

Radiation can be directed to still undamaged areas and thus the reliability can be increased.

For further embodiment of the light module is a trained for the detection of laser radiation

Provided detection element. The safety bar preferably comprises a deflection region with an at least partially reflecting surface, so that a plane incident along the primary radiation direction

Light beam is at least partially deflected onto the detection element. The detection element is set up in particular for detecting an increase in intensity of the detected light. If the radiation intensity exceeds a defined threshold, e.g. the laser light source are switched off by a control electronics.

It is conceivable that a detection element is arranged on the safety bar itself. This may be, for example, a temperature sensor.

In particular, the safety bar has a Absorption area with an absorbent surface on. By absorbing unconverted laser radiation, the safety bar heats up. Meets in the case of one

damaged wavelength converter more unconverted laser radiation on the safety bar on, this heats up more. By a temperature sensor is the

Temperature rise recorded. If the temperature exceeds a predetermined value, e.g. the laser light source are switched off by a control electronics. It is also conceivable to attach to the bracket an indication element, which in particular stains permanently when heated above a threshold. Based on the discoloration of the indication element may be defects or damage to the

Wavelength converters are diagnosed even when the light module is switched off.

For automotive lighting devices should the

Abstrahllichtverteilung often characteristic

Have properties that are partly regulated by law. In particular, a dimmed light distribution has a light-dark boundary, which covers a (below) illuminated area from one (overhead)

Dark area separates. According to one aspect of the invention, the safety bar can help to provide the desired

To achieve light distribution. For this purpose, the

Safety bar, for example, a bezel edge

which shades off a portion of the secondary light distribution and which thus with respect to

Abstrahloptikeinrichtung is arranged that the shadowed from the diaphragm edge secondary light distribution is converted into a Abstrahllichtverteilung with a light-dark boundary.

Further details and advantageous embodiments of the invention will become apparent from the following description, by means of which those shown in the figures

Embodiments of the invention are described and explained in detail. Show it:

Fig.l a sketch of a light module according to the invention in normal operation; Fig. 2 is a detail view of Fig. 1;

Fig. 3a is a detail view of an inventive

Light module in a further embodiment in

Normal operation;

Fig. 3b is a detail view of an inventive

Light module of Figure 3a in disturbed operation.

Fig. 4 is a detail view of an inventive

Light module in a further embodiment; and

Fig. 5 is a detail view of an inventive

Light module in another embodiment. In the figures and in the following description, identical or corresponding components and features are provided with the same reference numerals.

FIG. 1 shows a light module 10 for a motor vehicle headlamp with a laser light source 12 in FIG

Side view. This emits a primary light beam 14, which is concentrated around a Primärärabstrahlrichtung 16 in a small primary space angle range. In the normal operation shown in FIG

Primary light beam 14 on an optional intermediate optics 18, the primary light beam 14 to a

Wavelength converter 20 directs. The wavelength converter 20 is supported by a carrier component 22 in the beam path of the primary light bundle 14 of the laser light source 12

arranged. By the incident primary light beam 14 of the wavelength converter 20 is excited to emit a secondary light distribution 24, which preferably has incoherent, polychromatic or white light. Therefore, the secondary light distribution no longer has the potentially dangerous properties of laser light.

The secondary light distribution 24 fills a larger one compared to the primary space angle range

Secondary space angle range off. One in the illustrated

Example designed as a reflector 26

Abstrahloptikeinrichtung serves to convert the light beam of the secondary light distribution 24 in a Abstrahllichtverteilung 28 or deflect, which is substantially around a main emission direction 30 of the light module 10th

is concentrated.

The light module 10 comprises a safety bar 32 which is attached to the carrier component 22 of the wavelength converter 20

is arranged and has a mounting plane for the

Wavelength converter 20 in which the

Wavelength converter 20 or a light-emitting

Surface of the wavelength converter 20 is disposed protrudes. FIG. 2 shows an embodiment of a light module 10 in plan view of the carrier component 22

Wavelength converter 20 and attached to the support member safety bar 32. The safety bar 32 projects beyond the mounting plane of the wavelength converter 20. In particular, the wavelength converter 20 is in a central portion of the support member 22 is positioned. The safety bar 32 sets, for example, on a

Edge portion of the support member 22 and protrudes from the edge portion over the central region of the

Carrier component 22. In this respect, the safety bar 32 covers part of the surface of the wavelength converter 20. Thus, only a small part of the meets

Wavelength converter 20 emitted

Secondary light distribution 22 on the safety bar 32. The safety bar 32 is sized and arranged so that the primary space angle range is covered, in the

Run light beam, which starting from the

Laser light source 12 extend around the Primärärabstrahlrichtung 16. Ideally, only such light beams hit the safety bar 32, which starting from the

Laser light source 12 extend in a primary space angle range around the Pimaemrabrahlrichtung 16, so that a transformation in the Abstrahllichtverteilung 28 only for such

Light beam is suppressed. The emission light distribution 28 is generated essentially by the secondary light distribution 24. A suppression of light beams in the comparatively small primary space angle range about the primary radiation direction 16 therefore does not lead to a significant loss of power during normal operation or

Disturbances of the Abstrahllichtverteilung 28.

The safety bar 32 can on the

Wavelength converter 20 side facing a

Absorbing region 34 for absorbing laser radiation include. Due to the absorption of the laser radiation, the safety bar 32 heats up. If the wavelength converter 20 is damaged, a greater proportion of laser light strikes the safety bar 32. This heats up more. For example, a temperature sensor 36 attached to the safety bar 32 can detect the heating. FIGS. 3a and 3b show a schematic representation of the safety bar 32 of a light module 10 in a further embodiment in trouble-free operation (FIG. 3a) and in the event of a fault (FIG. 3b). The safety bar 32 comprises a reflection region 38 with a reflection surface 40 oriented obliquely to the primary radiation direction 16. In normal operation (FIG. 3 a), ie with an intact wavelength converter 20, the entire primary light bundle 14 is captured in the ideal case, and the

Secondary light distribution 24 generated. The

Secondary light distribution 24 radiates into the

Secondary space angle range from and only the part of

Secondary light distribution 24, which in the

Primary Abstrahlrichtung 16 runs, is of the

Safety bar 32 deflected. The remaining light beams of the secondary light distribution 24 are of the

Safety bar 32 not reflected and meet reflector 26th

If the wavelength converter 20 is damaged (FIG. 3b), the potentially dangerous laser light beam strikes

starting from the laser light source 12 and the

Intermediate optics 18 on the safety bar 32. By the reflection surface 40 of the safety bar 32, the incident light rays in one of

Main emission direction 30 of the light module 10 and the

Reflectors 26 directed away region and thus do not contribute to the Abstrahllichtverteilung 28 of the light module 10 at.

Figures 4 and 5 show further embodiments of a light module 10, wherein each of the abstract optics is not shown. On a circuit board 42 is a

Detection element 44 for detecting and monitoring the Radiation intensity of laser light and arranged to emit a detector signal. In Figure 4, the

Safety bar 32 a scattering area 46 with a

scattering surface 48 on. At least part of the light beam impinging on the safety bar 32 is directed by the scattering surface 48 onto a light guide 50 and guided in the light guide 50 onto the detection element 44. The light guide 50 is preferably designed such that only unconverted laser beams are conducted. This can be realized in particular by a coating of the light guide 50 or by the installation of an additional optical filter. Light bundle of

Secondary light distribution 24 which strike the light guide 50 are then absorbed and / or reflected and preferably do not reach the detection element 44.

The detection element 44 detects the radiation intensity of the incident light beam. In the case of a defect of the wavelength converter 20 hits the unconverted

Laser light beam on the safety bar 32 and thus also on the detection element 44. The detection element 44 then detects a (erratic) increase in

Radiation intensity and sends in case of a

Limit value exceeding the radiation intensity

Detection signal to an electronic control unit of

Laser light source 12. In order to avoid further damage to the light module 10, the laser light source 12 can in case of failure

be disabled due to the detection signal of. FIG. 5 shows an embodiment in which at least a part of the light beam impinging on the safety bar 32 passes through a transmission opening 52 in the

Carrier member 22 is guided on the detection element 44. Advantageously, in the transmission opening 52, an optical element 54, in particular a lens, a diffractive element, a color filter or a prism provided in order to adapt the light beam entering through the through-aperture 52 to the detection element 44.

Claims

A light module (10) for a motor vehicle headlamp, comprising: at least one laser light source (12) for emitting a primary light beam (14);

a wavelength converter (20) for converting the primary light beam (4) into a secondary light distribution (24);

a Abstrahloptikeinrichtung (26) for converting the secondary light distribution (24) in one

Emission light distribution (28) of the light module (10);

characterized in that

the laser light source (12) is designed such that the primary light bundle (14) into a

Primary space angle range is radiated around a primary radiation direction (16),

and that the wavelength converter (20) is such

is formed such that the primary light beam (14) in the primary space angle range around the

Primary Abstrahlrichtung (16) around on the

Wavelength converter (20) hits,

and that a support member (22) for supporting the

Wavelength converter (20) is provided, and that the support member (22) has a safety bar (32) which, starting from the

Wavelength converter (20) considers the

Primary space angle area to the primary radiation direction (16) covered.

Light module (10) according to claim 1, characterized

characterized in that the safety bar (32) is fixedly connected to the carrier component (22), wherein the

Safety bracket (32) projects beyond a mounting plane for the wavelength converter (20). Light module (10) according to the preceding claim, characterized in that the safety bar (32) in its further course spaced from the

Holder level and along the mounting plane extends.

Light module (10) according to one of the preceding claims, characterized in that the safety bar (32) has an absorption region (34), which is designed such that the incident laser light

is absorbed.

Light module (10) according to one of the preceding claims, characterized in that the absorption region (34) completely covers only the primary space angle range.

Light module (10) according to one of the preceding claims, characterized in that the safety bar (32) comprises a scattering area (46) with a scattering surface (48) such that an incident light beam is scattered to the side or diffused.

Light module (10) according to one of the preceding claims, characterized in that the safety bar (32) has a reflection area (38) with a

Reflection surface (40) which is arranged such that a along the

Primary Abstrahlrichtung (16) incident light beam is deflected so that it is not for

Abstrahllichtverteilung (28) contributes.

Light module (10) according to one of the preceding claims, characterized in that the safety bar (32) a back reflection area (38) having a

reflective surface (40) such that a along the primary radiation direction (16)

incident light beam back to the

Wavelength converter (20) is directed.

Light module (10) according to one of the preceding claims, characterized in that the safety bar (32) has a deflection region with a reflective

Surface such that one along the

Primary radiation direction (16) incident light beam on a trained for the detection of laser radiation detection element (44) is deflected.

Light module (10) according to one of the preceding claims, characterized in that on the safety bar (32), a detection element (36), in particular for the detection of temperature, and / or a

Indication element, in particular for the indication of temperature is arranged.

Light module (10) according to any one of the preceding claims, characterized in that the safety bar (32) has at least one diaphragm edge, which shadows a portion of the secondary light distribution and which in relation to the

Abstrahloptikeinrichtung (26) is arranged that the shaded from the diaphragm edge

Secondary light distribution (24) in one

Abstrahllichtverteilung is formed with a light-dark boundary.