DE102015205866A1 - High beam module - Google Patents

Abstract

The invention relates to a high-beam module (12) for a headlight (10), comprising a reflector (18) and a first semiconductor light source (22) arranged in the focal region of the reflector, from which a luminous flux of primary light with wavelengths emerges from a primary wavelength range, and with a fluorescent layer (26) which generates white mixed light from the primary light and with a second semiconductor light source (28) arranged outside the focal area (20). The high-beam module is characterized in that the second semiconductor light source is a light emitting diode, from which a luminous flux containing primary light and which is directed with the aid of a light guide to the fluorescent layer, so that the light emitting diode stimulates the fluorescent layer to produce white mixed light.

Description

The present invention relates to a high beam module for a motor vehicle headlight according to the preamble of claim 1.

Such a high beam module is from the EP 2 487 407 and comprises a reflector, a first semiconductor light source, and a second semiconductor light source. The reflector has a focal area. The first semiconductor light source is arranged in the focal region of the reflector. It has a first emission surface from which, during operation of the first semiconductor light source, a first luminous flux of primary light emerges with wavelengths from a primary wavelength range. The first emission surface is covered with a fluorescent layer which generates white mixed light from the primary light.

The second semiconductor light source is a laser diode arranged outside the focal region, which emits blue light which is directed onto a central subregion of the fluorescent layer and excites this to an increased emission of white mixed light. Due to this configuration, a central area of the main beam distribution should be particularly bright. The first semiconductor light source and the second semiconductor light source are operated simultaneously to generate the high beam distribution.

In the known article, the primary light belongs to a wavelength range of blue light color. The reflector has a first region, referred to as a reflection surface, and a second region, referred to as a focusing reflection surface. The first semiconductor light source consists of two light-emitting diodes, each of which has an emission area which is one square millimeter in size. The light-emitting diodes are arranged closely adjacent to one another with mutually parallel side edges.

The fluorescent layer, which converts the blue light, covers the entirety of the individual emission surfaces in a coherent manner and projects laterally about 5/100 millimeters beyond the emission surfaces. Part of the blue light emitted by the light-emitting diodes stimulates the fluorescent layer to emit light from the yellow-red spectral range. The yellow-red light mixes with unconverted blue light of the LEDs additively to white mixed light, which propagates from the fluorescent layer and illuminates the first region of the concave mirror reflector with a wide opening angle.

A focal region of the first region lies in the center of the surface of the fluorescent layer. The first region of the reflector focuses the white mixed light emanating from the fluorescent layer into an inner light distribution which is projected by the projection lens as a second light distribution into the apron of the light module. The second semiconductor light source is a laser diode and is remote from the two light-emitting diodes on the optical axis of the first region of the reflector. The laser beam emanating from the laser diode blue light is focused by a lens and falls at an acute angle to the light exit surface of the converter layer.

There, a specular reflection takes place, through which the incident laser light is directed to the second area. The specularly reflected light is focused by the second region of the reflector into a small area on the surface of the converter layer, which is thereby increasingly excited to fluorescence and increased emission of white mixed light. The amplified emitting small area appears in the second light distribution as a central, brighter spot.

Known per se are also high beam modules for motor vehicle headlights, which in addition to the function of generating a headlight distribution in the form of a high beam distribution, also fulfill the function of generating a signal light distribution in the form of a daytime running light distribution and / or a limiting light distribution, said light distributions of a and the same reflector chamber are generated.

In these known per se high beam modules each have an incandescent lamp, a gas discharge lamp or a light emitting diode or group of LEDs for the generation of the high beam is present. This high beam light source is usually arranged in the focal region of the reflector. At least one further light source, such as an incandescent lamp or a light-emitting diode, is present for the generation of the daytime running light and / or the limiting light. This further light source is not usually arranged in the focal region of the reflector, because this space is already occupied by the light source for the high beam.

In an arrangement of the other light source (s) outside the focal range of the reflector, there is the disadvantage of uneven illumination of the reflector, resulting in an undesirable inhomogeneous appearance of the light module in the daytime running mode and / or Begrenzungslichtbetrieb.

If light-emitting diodes are used as light sources for the high beam, one might think of using the same LEDs in a dimmed operation for generating the daytime running lights and / or the limiting light. However, this fails because of the large differences in the respective required light intensities (power per solid angle unit). At least 40000 cd are required for a high beam, while a daytime running light has to deliver around 400 cd and a limiting light only about 40 cd. The dimming ratios are thus 1 to 100, or 1 to 1000. This is not feasible with conventional control electronics with reasonable effort.

Now one could think of generating the high beam distribution only with the light emitting diode pair and to generate a daytime running light and / or a limiting light with a further light emitting diode, which at the location of the laser diode of the EP 2 487 407 A2 is arranged and generates only a sufficiently small light intensity. However, this would affect the generation of the high beam distribution, since in this case the contribution of the laser diode for generating the high beam distribution would be omitted.

In addition, the concentrated shape of the bright center of the high beam distribution generated by the laser diode would not be suitable for producing daytime running lights and / or headlights, as these signal light distributions are comparatively wider than a central high beam spot and, for example, in a horizontal angle range of 40 ° width and a vertical angle range from 20 ° width must have certain fractions of their maximum light intensity.

In addition, the spatial separation of the light sources, such as the EP 2 487 407 A2 can be removed, a very narrow beam focusing arranged outside the focal range of the reflector light source. Such narrow beam bundling can indeed be achieved with laser diodes. For market-driven realization of a marker light or daytime running lights, which is each weaker by orders of magnitude than that of the EP 2 487 407 A2 known high-beam spot, however, laser diodes are not suitable because they are too expensive and too strong.

On the other hand, the laser diode of the known object can not be easily replaced by a sufficiently weak LED, because conventional (blue) light emitting diodes radiate in comparatively wide aperture angle, so that much blue light would pass the converter layer and in the generation of the headlight or daytime running lights would disturb.

Against this background, the object of the invention in the specification of a high beam module of the type mentioned, with which also a daytime running light distribution and / or a limiting light distribution can be generated with the reflector of the high beam module, and in the daytime running mode and / or in the limiting light mode a homogeneous bright appearance has.

This object is achieved with the features of claim 1. From the above-mentioned prior art, the present invention differs in that the second semiconductor light source is a light-emitting diode having a second emission surface from which emerges in operation of the light emitting diode, a second light flux containing primary light having wavelengths from the primary wavelength range, and in that the high-beam module has an optical waveguide with a light entrance surface and a light exit surface, wherein the light entry surface is arranged directly in front of the emission surface of the light emitting diode and the light exit surface of the optical fiber laterally lies in front of the fluorescent layer such that primary light emerging from the light exit surface of the LED illuminates the fluorescent layer of white mixed light stimulates.

The fact that the second semiconductor light source is a light-emitting diode having a second emission surface from which emerges during operation of the light emitting diode, a second luminous flux of primary light having wavelengths from the primary wavelength range, is primary light for a second light function, for example for a daytime running light and / or Limiting light provided.

The fact that the provision is made by a second light source, the problems of excessive demand of a control electronics are avoided by excessive dimming.

The fact that the high beam module has a light guide with a light entrance surface and a light exit surface, the invention allows the transport of the light of the second light source without the light of the second light source must be radiated particularly bundled this. As a light source can therefore use a simple light emitting diode used. A laser diode is not required at this point.

The fact that the light entry surface is arranged directly but without contact in front of the emission surface of the light emitting diode, a very high proportion of the radiated light from the light diode is coupled into the light guide, which is favorable for the efficiency of generating a second light function and what additionally an undesirable lighting of the interior of the high beam module is minimized by the light of the second light source.

Due to the fact that the light exit surface of the light guide lies laterally in front of the fluorescent layer such that primary light of the light emitting diode exiting the light exit surface stimulates the fluorescent layer to produce white mixed light, the second light source can excite the fluorescence layer optimally arranged with respect to the reflector, see also US Pat that this ultimately emits white mixed light, which has an appropriate intensity for the second light function and which illuminates the reflector homogeneously because of the optimal arrangement of the fluorescent layer.

A preferred embodiment is characterized in that the second semiconductor light source is adapted to emit only a fraction of the luminous flux emitted by the first semiconductor light source.

It is also preferable that the primary wavelength region is a wavelength region containing wavelengths of visible light of blue color.

Further, it is preferable that the light color of the light emitted from the second semiconductor light source is the same light color as the light color of the light emitted from the first semiconductor light source.

A further preferred refinement is characterized in that the second semiconductor light source is a semiconductor light source emitting white light.

It is also preferable that the first emission surface is covered with a fluorescent layer which generates white mixed light from primary light.

Furthermore, it is preferred that the fluorescent layer has a first, central region that is illuminated by both semiconductor light sources, and that the fluorescent layer has a second, peripheral region that is illuminated only by the second semiconductor light source.

A further preferred embodiment is characterized in that both semiconductor light sources are arranged on the same board and also with thermal contact to the same heat sink.

It is also preferable that the light guide is a rigid plastic part.

Furthermore, it is preferred that the light guide has the same cross-sectional profile over its entire length.

A further preferred embodiment is characterized in that the light exit surface is designed such that the light emerging from the light guide illuminates the entire surface of the fluorescent layer distributed over the surface.

Furthermore, it is preferred that the light entry surface of the light guide is at least as large as the second emission surface and arranged so that it completely covers the second emission surface.

It is also preferred that the light entry surface is larger than the second emission surface and is arranged so that it protrudes uniformly beyond the edges of the second emission surface.

A further preferred embodiment is characterized in that the second semiconductor light source is adapted to emit in addition to the primary light also light of wavelengths other than the wavelength of the primary light, which together with the primary light give white light.

Further advantages will become apparent from the following description, the drawings and the dependent claims. It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination given, but also in other combinations or in isolation, without departing from the scope of the present invention.

Embodiments of the invention are illustrated in the drawings and are explained in more detail in the following description.

Show, in schematic form:

1 a longitudinal section through an embodiment of a high-beam module according to the invention; and

2 a plan view of an array of fluorescent layers having a central and a peripheral region.

In this case, the same reference numerals in different figures denote the same or at least functionally comparable elements.

In detail, the shows 1 a longitudinal section through a motor vehicle headlight 10 with an embodiment of a high-beam module according to the invention 12 , The x-direction indicated there corresponds to a main emission direction of the high-beam module. This x-direction is at a proper use of the high beam module perpendicular to a horizontal H and a vertical V. The high beam module is in a housing 14 of the headlight arranged. A transparent cover 16 covers a light exit opening of the housing.

The high beam module has a reflector 18 on, the one focal area 20 having. The focal area is for example a small, a focal point enclosing volume with a radius of up to 5 millimeters.

In the focal region of the reflector is a first semiconductor light source 22 arranged. The first semiconductor light source has a first emission surface 24 on, from which emerges during operation of the first semiconductor light source, a first luminous flux of primary light having wavelengths from a primary wavelength range. The first semiconductor light source is preferably a laser diode or light-emitting diode or an arrangement of such diodes. The first emission area 24 is with a fluorescent layer 26 which produces primary white mixed light.

Such generation of white mixed light and suitable materials for the fluorescent layer (usually phosphorus compounds) are known. The white mixed light is emitted without any particular preferential direction approximately isotropically or at least with a very large opening angle, which also includes backward scattering with respect to the directions of the incident light. This is a known property of common fluorescent materials.

The isotropically emitted light causes the reflector 18 from his focal area 20 out homogeneously illuminated. Due to its shape, the reflector is set up to generate a rule-conforming high beam distribution from the light which is incident on it from the focal area. This is known as such and therefore needs no further explanation here.

The high beam module has a second semiconductor light source 28 on, outside the focal area 20 in the spotlight 10 , especially in the high beam module 12 is arranged. The arrangement in the high beam module is preferred because then both semiconductor light sources on the same board 27 and optionally also with thermal contact on the same heat sink 29 can be arranged. Advantageously, the second semiconductor light source is arranged outside the light beam, that of the fluorescent layer 26 goes out and the reflector 18 illuminated.

The second semiconductor light source 28 is preferably a light emitting diode, or array of light emitting diodes, having an emitting surface. This emission area will be differentiated from the first emission area below 24 belonging to the first semiconductor light source as the second emission surface 30 designated. The second semiconductor light source 30 is configured to emit a second luminous flux of primary light with wavelengths from the primary wavelength range. This is preferably the same wavelength range of blue light from which the primary light of the first semiconductor light source originates. In principle, it is sufficient if the second luminous flux has spectral components from the stated wavelength range. In addition, the second luminous flux can also have other spectral components.

The high beam module also has a light guide 32 with a light entry surface 34 and a light exit surface 36 on. The light entry surface 34 is directly but non-contact in front of the second emission surface 30 , ie in front of the emission surface of the second semiconductor light source, which is preferably realized as a light-emitting diode 28 arranged.

The light entry surface 34 is preferably at least as large as the second emission surface 30 and arranged to completely cover the second emission surface. In a preferred embodiment, the light entry surface 34 larger than the second emission surface and arranged so that it projects evenly beyond the edges of the second emission surface. In this way, a maximum of the outgoing light beam from the second emission surface in the light guide 32 coupled.

The light exit surface 34 of the light guide 32 lies laterally in front of the fluorescent layer so that exiting the light exit surface primary light of the LED excites the fluorescent layer to produce white mixed light. Again, the white mixed light from the fluorescent layer 26 essentially isotropically emitted without preferential direction. As a result, the reflector 18 is also homogeneously illuminated by the light generated by the second semiconductor light source from its focal region.

The second semiconductor light source emits only a fraction of the light emitted by the first semiconductor light source. In particular, it is preferable to use a second light source of corresponding intensity less light. Accordingly, the light intensity in the (only) light distribution resulting from the light of the second semiconductor light source is then weaker than the light intensity of the light distribution (only) produced with the light of the first semiconductor light source.

Although both light distributions are generated by spatially separated semiconductor light sources, the respective excitation results in the focal region 20 arranged fluorescent layer ultimately a homogeneous, emanating from this fluorescent layer illumination of the reflector. Since the intensity distributions (unlike the absolute intensity values) of a rule-compliant main beam distribution on the one hand and a rule-compliant daytime running light distribution or a rule compliant boundary light distribution on the other side are similar, these light distributions can be with the same reflector produce, and the reflector offers in all three cases a homogeneous bright appearance, attractive appearance.

The limiting light distribution and the daytime running light distribution are preferably generated with light of the second semiconductor light source. In the operation for generating the limit light, the second semiconductor light source is dimmed compared with the operation for generating the daytime running light.

For controlling the semiconductor light sources is a control unit 36 , which in turn signals an input device 38 with which the desired light function, be it a high beam, a daytime running light or a limiting light, is selected. The input device is a driver input device such as a light switch or a control device that controls the light functions, or an environment sensor system for controlling the light functions, for example an oncoming traffic sensor, a brightness sensor, and so on.

In a headlamp system having a separate from a high beam module light module for the daytime running lights and / or the limiting light, however, provides a preferred embodiment, that the high beam module has the features of the invention described herein and is operated so that it by illuminating to produce a Daytime running light distribution and / or limiting light distribution contributes.

As already mentioned, the second light-emitting diode is preferably a light-emitting diode which emits a primary luminous flux with wavelengths from the primary wavelength range. The primary wavelength region is preferably a wavelength region containing wavelengths of visible light of blue color. It is particularly preferred that the light color of the light emitted by the second semiconductor light source is the same light color as the light color of the light emitted by the first semiconductor light source. In a preferred embodiment, this last-mentioned light is blue light, since it is easy to produce white mixed light from blue light with the aid of known fluorescent layer materials.

In an alternative embodiment, the second semiconductor light source is a white light-emitting semiconductor light source. White light also contains blue components, which also produce white mixed light components on incidence on the fluorescent layer. However, then the intensity of the white mixed light generated is much lower than in the case of using a second semiconductor light source, which emits predominantly blue light. This is because the blue component of the white mixed light of a white light emitting semiconductor light source is much smaller than that of a semiconductor light source whose light is clearly dominated by the blue component. The first semiconductor light source is therefore preferably a blue light emitting laser diode.

The light guide is preferably a rigid plastic part. As a plastic material is for example PMMA (polymethyl methacrylate) or PC (polycarbonate) in question. The optical waveguide preferably has the same cross-sectional profile over its entire length, so that therefore the shape and size of the cross-sectional area remain constant over the length of the optical waveguide.

The light exit surface 34 is preferably designed so that the light emerging from the light guide is not focused on a point on the fluorescent layer, but that this light illuminates the entire surface of the fluorescent layer distributed over the surface. In a preferred embodiment, the light exit surface is provided with a reflection-reducing coating. The coating is preferably adapted to the narrow spectral bandwidth of the light in the light guide, which increases the efficiency of the light guide. The adaptation is understood to mean that the transmission of the coating in the spectral region of the light propagating in the optical waveguide is higher than in the spectral regions adjacent to this spectral region.

A further preferred embodiment is characterized in that the fluorescent layer has a first, central region that is illuminated by both semiconductor light sources, and that the fluorescent layer has a second, peripheral region that is illuminated only by the second semiconductor light source.

Each illuminated by one of the two semiconductor light sources range, since it emanates from the white mixed light, in turn, a light source for the white mixed light, which is also referred to below to distinguish from the two semiconductor light sources as a substitute light source. In this embodiment, therefore, the replacement light source, or their white mixed light emitting surface for the daytime running light and / or the limiting light is greater than the replacement light source, which provides the white mixed light for the high beam.

The 2 shows a plan view of a spare light source 42 comprising a two-part fluorescent layer having a central region and a peripheral region surrounding the central region 46 having. In one refinement, the central region is located on the first emission surface (that is to say on the first semiconductor light source) and then forms a component of the first semiconductor light source. The peripheral region lies in one embodiment a frame having an opening in which the central area is arranged.

The 2 also shows a first emission area 24 consisting of four individual emitters 24.1 to 24.4 composed, which are arranged in the directions indicated in the manner of a longitudinal spiral in the reflector. The individual emitters form a row aligned along the main emission direction x. By juxtaposing multiple emitters, the high luminous flux required for a high beam can be easily generated from inexpensive single emitters. The invention is not limited to the use of four individual emitters. Depending on the design of the reflector, the arrangement of the individual emitter can also take place in the manner of a transverse spiral, ie in a row oriented along the H direction. The individual emitters can be light-emitting diodes or laser diodes.

Instead of a concave mirror reflector, as used in the embodiment, which in the 1 is shown, a transparent solid can be used as a reflector. To imagine such a transparent solid, you can see the cavity between the 1 and heat sink with board, light sources and the light guide as a mold, which is poured with transparent plastic such as PMMA or PC.

The light guide of the 1 is then a hollow air duct. In such a realization, only the shape of the light exit surface would have to be adapted to the exchanged refractive indices (air, plastic). For example, the oblique light exit surface of the light guide would not have to run from top left to bottom right, but vice versa from bottom left to top right, so that the emerging rays are incident on the fluorescent layer as desired.

In the in the 1 illustrated embodiment, the light guide along the optical axis of the reflector, that is arranged aligned along the main emission direction. However, the light guide can also be different, in particular run transversely to the optical axis and or have a curved course.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 2487407 [0002]
• EP 2487407 A2 [0012, 0014, 0014]

Claims (14)

High beam module ( 12 ) for a motor vehicle headlight ( 10 ), with a reflector ( 18 ), which has a focal area ( 20 ), and with a arranged in the focal region of the reflector first semiconductor light source ( 22 ), which has a first emission surface ( 24 ), from which emerges during operation of the first semiconductor light source, a first luminous flux of primary light having wavelengths of a primary wavelength range and which first emitting surface with a fluorescent layer ( 26 ), which generates white mixed light from primary light, and with a second semiconductor light source ( 28 ) outside the focal area ( 20 ), characterized in that the second semiconductor light source is a light emitting diode having a second emission surface ( 30 ), from which emerges during operation of the light emitting diode, a second luminous flux containing primary light with wavelengths from the primary wavelength range, and that the high beam module, a light guide ( 32 ) with a light entry surface ( 33 ) and a light exit surface ( 34 ), wherein the light entry surface is arranged directly but without contact in front of the emission surface of the light emitting diode and the light exit surface of the light guide laterally in front of the fluorescent layer, that exiting the light exit surface primary light of the LED excites the fluorescent layer to produce white mixed light. Light module ( 12 ) according to claim 1, characterized in that the second semiconductor light source ( 28 ) is adapted to emit only a fraction of the luminous flux emitted by the first semiconductor light source ( 22 ) is delivered. Light module ( 12 ) according to one of the preceding claims, characterized in that the primary wavelength range is a wavelength range containing wavelengths of visible light of blue color. Light module ( 12 ) according to one of the preceding claims, characterized in that the light color of the light emitted by the second semiconductor light source ( 28 ) emitted light is the same light color as the light color of the first semiconductor light source ( 22 ) emitted light. Light module ( 12 ) according to one of claims 1 to 3, characterized in that the second semiconductor light source ( 28 ) is a white light emitting semiconductor light source. Light module ( 12 ) according to one of the preceding claims, characterized in that the first emission surface ( 24 ) with a fluorescent layer ( 26 ), which generates primary white mixed light. Light module ( 12 ) according to one of the preceding claims, characterized in that the fluorescent layer has a first, central region which is illuminated by both semiconductor light sources, and in that the fluorescent layer has a second, peripheral region, which is illuminated only by the second semiconductor light source. Light module ( 12 ) according to one of the preceding claims, characterized in that both semiconductor light sources on the same board 27 and optionally also with thermal contact on the same heat sink 29 are arranged. Light module ( 12 ) according to one of the preceding claims, characterized in that the light guide is a rigid plastic part. Light module ( 12 ) according to one of the preceding claims, characterized in that the light guide has the same cross-sectional profile over its entire length. Light module ( 12 ) according to one of the preceding claims, characterized in that the light exit surface 34 is designed so that the light emerging from the light guide distributed over the entire surface of the fluorescent layer illuminates. Light module ( 12 ) according to one of the preceding claims, characterized in that the light entry surface 34 of the light guide at least as large as the second emission surface 30 and is arranged to completely cover the second emission surface. Light module ( 12 ) according to one of the preceding claims, characterized in that the light entry surface 34 larger than the second emission surface and arranged to project evenly beyond the edges of the second emission surface. Light module ( 12 ) according to one of the preceding claims, characterized in that the second semiconductor light source is adapted to emit in addition to the primary light also light of wavelengths other than the wavelength of the primary light, which together with the primary light give white light.

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