DE102013200521B4 - Primary optical device for motor vehicle headlights with laser light source, layer-like photoluminescence element, light-guiding element and reflection surfaces for light from the photoluminescence element and corresponding motor vehicle headlights - Google Patents

Abstract

Primary optical device (10, 40, 50) for motor vehicle headlights with at least one laser light source, - with a photoluminescence element (26), which is designed in such a way that a mixed light distribution (28) can be emitted by incident laser radiation (L) using photoluminescence, - with an irradiation section (19; 18, 42), through which laser light (L) can be irradiated onto the photoluminescent element (26), - with a light guide body (14) having a light exit surface (16) for guiding the light of the mixed light distribution to the light exit surface (16 ), through which light can emerge to form a primary light distribution (34), the light-guiding body (14) being delimited by at least one collecting reflection surface (32) in such a way that light of the mixed light distribution (28), which runs in the light-guiding body (14), is included the light exit surface (16) is deflected, a deflection reflection surface (24, 44) being provided, which is designed and arranged in such a way that light from the mixed light distribution (28) emitted by the photoluminescent element (26) is directed to the by means of the deflection reflection surface (24, 44). Collecting reflection surface (32) can be deflected, characterized in that the photoluminescence element (26) is formed in a layer-like manner on a thermally conductive component that is separate from the light-conducting body (14), an irradiation surface (22) forming the deflection reflection surface (24) coming from the layer-like photoluminescence element (26). is covered, the irradiation surface (22) facing a central transmission opening (18) which is delimited by the light-guiding body (14).

Description

The invention relates to a primary optical device for motor vehicle headlights with a laser light source according to the preamble of claims 1 and 2, and a motor vehicle headlight with a laser light source according to the preamble of claim 11.

US 2012 / 0 230 011 A1 already discloses a primary optics device according to the respective preamble of claim 1 or 2. When producing the primary optics device, phosphor powder is dispersed in a transparent material.

Laser light sources, in particular semiconductor lasers, offer a number of potentially advantageous properties, such as a comparatively small light-emitting area, high radiation intensities, and the emission of largely collimated light bundles. Optical systems for laser light can therefore be implemented with little installation space, for example because smaller focal lengths can be selected than for optical systems for less strongly collimated light beams from, for example, incandescent lamps or conventional light-emitting diodes (LEDs). The use of laser light sources can therefore enable a compact design for vehicle headlights.

However, problems with the use of laser light sources for automotive headlights arise from the fact that lasers essentially emit coherent, monochromatic light or light in a narrow wavelength range. However, white mixed light is usually desirable or legally required for the light emitted by a vehicle headlight. In addition, the beam light distribution should usually have certain intensity curves, some of which are prescribed by law. Measures must therefore be taken to convert it into suitable light.

To convert monochromatic light into, for example, white mixed light, the use of photoluminescence converters or photoluminescence elements is known in the field of white light-emitting diodes (LEDs) or luminescence conversion LEDs. These have, for example, a photoluminescent dye in a, for example, semi-transparent substrate and are arranged directly on the light-emitting section of the LED. The light from an LED that emits colored (e.g. blue) light stimulates the photoluminescent dye to photoluminesce, whereby the photoluminescent dye itself emits light of a different wavelength (e.g. yellow). In this way, at least part of the irradiated light from one wavelength range can be converted into light from another wavelength range. As a rule, a further portion of the irradiated light is scattered by the photoluminescent element. The scattered light and the light emitted by photoluminescence can then be additively superimposed and achieve the desired, e.g. white, mixed light.

When using the principle of photoluminescence conversion for motor vehicle headlights with a laser light source, the mixed light emitted by the photoluminescence element is generally not collimated, more diffuse and homogeneous compared to the irradiated laser light bundle. The photoluminescent element therefore distributes the energy of the laser light source over a large solid angle range. There is therefore the possibility that part of the light energy of the laser light source is lost after conversion into mixed light and the advantageous properties of the laser light source cannot be fully utilized and the efficiency is reduced.

In the US 2011 / 0 148 280 A1 A car headlight is described with a plurality of laser diodes as a light source. A light-guiding element is arranged in the beam path after the laser diodes, which guides the laser beams that can be emitted by the laser diodes to a common light-emitting surface of the light-guiding element, through which a collecting light bundle of laser light can emerge. A photoluminescence converter is arranged in the further beam path in such a way that the collecting light beam hits the photoluminescence converter and stimulates it to emit a mixed light distribution. The emitted mixed light is redirected via a secondary reflector into a beam light distribution of the headlight. The headlight described does not have a primary optical element, which serves to preform the mixed light generated into a primary light distribution.

The WO 2008/ 149 265 A1 shows a collimator by means of which the irradiable light from a substantially monochromatic light source (e.g. colored LED) can be converted into, for example, white mixed light, which has a primary light distribution that is possible for use in motor vehicle headlights. The collimator has a light guide body with a light entry window and a light exit surface and is further limited by a reflective side surface. A luminescent layer with a photoluminescent dye is arranged immediately adjacent to the light entry window. The mixed light that can be generated by the luminescent layer by irradiating monochromatic light runs in the light-guiding body, is optionally deflected on its side surface to the light exit surface and exits the collimator through this.

The invention is based on the object of an efficient conversion for a motor vehicle headlight of the light from laser light sources in mixed light and also to make the mixed light usable as efficiently as possible.

This object is achieved according to the invention by a primary optical device with the features of claim 1, and by a motor vehicle headlight with the features of claim 7.

The primary optical device according to claim 1 serves to achieve a primary light distribution from the light of at least one light source and comprises a photoluminescence element which is designed such that a mixed light distribution can be emitted using photoluminescence when the laser radiation hits it. The mixed light is emitted in particular by partially converting the irradiated laser light via photoluminescence and by partially (in particular diffuse and/or incoherent) scattering of the laser light on the photoluminescent element. Substantially uninfluenced portions of the irradiated light (or, for example, merely redirected portions or portions reflected at interfaces) can also contribute to the formation of the mixed light. The converted light has a wavelength that deviates from the wavelength of the irradiated laser light and can mix with the light scattered on the photoluminescent element to form, for example, white light. The photoluminescent element is preferably designed to generate a white mixed light distribution from the light from the laser light source.

The primary optical device further comprises an irradiation section through which laser light can be irradiated onto the photoluminescent element. In addition, a light-guiding body is provided for guiding the light of the mixed light distribution, the light-guiding body having at least one light exit surface through which light can emerge to form a primary light distribution of the primary optical device. The light-guiding body is delimited by at least one collecting reflection surface in such a way that at least portions of the light of the mixed light distribution, which runs in the light-guiding body, are deflected to the light exit surface by the collecting reflection surface.

According to the invention, the primary optical device has a deflection reflection surface, which is designed and arranged in such a way that light from the mixed light distribution that can be emitted by the photoluminescent element is deflected to the collecting reflection surface by means of the deflection reflection surface.

The deflection reflection surface is arranged in such a way that at least a portion of the mixed light distribution emitted by the photoluminescent element (through conversion and/or transmission and/or scattering of the irradiated laser beams) first hits the deflection reflection surface before hitting the collecting reflection surface. At least for this portion of the mixed light distribution, the deflection reflection surface and then the collecting reflection surface act one after the other. The collecting reflection surface can be designed in such a way, in particular shaped in such a way, that a primary light distribution with the desired properties can emerge through the light exit surface. By appropriately designing the collecting reflection surface, the primary light distribution can, for example, be given a specific intensity profile or a specific boundary shape (e.g. oval spot light distribution or light-dark boundary).

Preferably, the light guide body and/or the collecting reflection surface is designed such that the primary light distribution is collimated or converges along a radiation direction starting from the light exit surface. However, divergent properties can also be advantageous for certain applications. The primary light distribution can then be deflected or projected into the desired beam light distribution, for example in the area in front of the vehicle, in a motor vehicle headlight, for example by means of a secondary optical device following in the beam path. In this respect, the collecting reflection surface can have beam-shaping properties. The collecting reflection surface preferably essentially covers a complete half-space around the photoluminescent element in order to efficiently use the emitted radiation.

The deflection reflection surface can be designed in such a way that the mixed light distribution emitted by the photoluminescent element reaches the collecting reflection surface as completely as possible and can be redirected from it into the primary light distribution. In particular, such light beams, which propagate from the photoluminescent element in a direction away from the collecting reflection surface, can be redirected to the collecting reflection surface by means of the deflection reflection surface. This can increase the efficiency of the headlight.

The deflection reflection surface can also have additional beam-shaping properties. It is conceivable, for example, that the deflection reflection surface has a preferably straight boundary edge. This can, for example, separate a reflective region and a light-absorbing region from one another. Additionally or alternatively, the photoluminescent element can also be delimited by a boundary edge, which is preferably straight runs. The boundary edge of the deflection reflection surface and/or the photoluminescence element can be imaged as a light-dark boundary when laser light is irradiated onto the photoluminescence element via the collecting reflection surface.

To shape the primary light distribution, the primary optical device can also have diaphragm means, which are arranged in the beam path, for example between the deflection reflection surface and the collecting reflection surface or the collecting reflection surface and the light exit surface. At least one filter layer (in the sense of an optical filter) can also be provided, which is arranged, for example, on the deflection reflection surface and/or on the photoluminescent element and/or on a further boundary surface of the light-guiding body.

For the portion of the mixed light distribution that can be emitted by the photoluminescence element and which hits the deflection reflection surface, the deflection reflection surface is therefore arranged in the beam path after the photoluminescence element and in front of the collecting reflection surface. The light of the mixed light distribution emitted by the photoluminescent element can again hit the photoluminescent element or radiate through it after being deflected through the deflection reflection surface. The deflection reflection surface preferably deflects light in such a way that it runs in the light guide body to the collecting reflection surface.

When the primary optical device is supplied with a laser light source, the photoluminescent element acts as the actual light source which emits the mixed light distribution and which feeds the primary light distribution. In order to achieve efficient use and to enable a precise design of the primary light distribution through the collecting reflection surface, the effective surface of the photoluminescent element can, for example, be made as small as possible compared to the surface of the collecting reflection surface.

It is conceivable that the light-guiding body, in particular in the beam path after the collecting reflection surface, comprises at least one light-guiding section, which is delimited by side surfaces in such a way that light rays running in the light-guiding section can be guided to the light exit surface under total internal reflection. Total internal reflection occurs on a side surface when a light ray striking the side surface forms an angle to the perpendicular to the side surface at the reflection point which exceeds the critical angle of total reflection, so that the law of refraction (Snellius law) does not provide a real solution for the angle of refraction results. The at least one light-guiding section can be designed in such a way that the mixed light distribution deflected by the collecting reflection surface is reshaped in accordance with the (e.g. legal) requirements. For example, the light-guiding section can be set up to collimate or narrow the mixed light distribution shining through it. For this purpose, the light-guiding section can have a cross section that widens along its course from the collecting reflection surface to the light exit surface, i.e. it can be delimited by diverging side surfaces.

According to an advantageous embodiment, the light-guiding body has a light coupling surface which forms the irradiation section of the primary optical device. The light from a laser light source coupled in through the light coupling surface runs in the light guide body after coupling in such a way that it can impinge on the photoluminescent element.

The photoluminescent element is preferably arranged on the light coupling surface. The photoluminescent element is then particularly partially transparent or semi-transparent, so that the transmitted, possibly scattered light can mix additively with the light converted via photoluminescence to form a particularly white mixed light.

However, the laser light beam does not necessarily have to run in the light-guiding body before striking the photoluminescent element. It is also conceivable that the light-guiding body has a transmission opening or transmission recess, which forms the irradiation section of the primary optical device. The photoluminescence element is then preferably arranged after the transmission opening in such a way that laser light can be irradiated onto the photoluminescence element through the transmission opening. Such configurations make it possible to cool the photoluminescent element independently of the light-guiding body and thus extend its service life. For example, a heat sink can be arranged after the radiation opening, with the photoluminescent element being arranged on the heat sink. The light guide body preferably limits the transmission opening in a torus-like manner. However, it is also conceivable that the light-guiding body has a plurality of spaced, for example sector-like, body sections which are arranged around a transmission opening.

For all embodiments of the invention, the collecting reflection surface is preferably arranged on a section of the light guide body that faces the laser light source during operation of the primary optics device, and the deflection reflection surface is arranged on a section of the light guide body during operation of the primary optics device the side of the light-guiding body facing away from the laser light source (on the light-guiding body or spaced from it). The collecting reflection surface can be arranged, for example, next to or surrounding the irradiation section, and the deflection reflection surface can be arranged, for example, opposite the irradiation section. In particular, it is conceivable that the collecting reflection surface is arranged opposite the deflection reflection surface with respect to a main irradiation direction running from the irradiation section to the photoluminescent element (if necessary offset radially outwards with respect to the main irradiation direction). As a result of the configurations mentioned, an irradiated laser light beam, optionally after conversion on the photoluminescent element, is reflected back by the deflection reflection surface in a substantially opposite direction to the main irradiation direction and then directed to the light exit surface by means of the collecting reflection surface. This beam path makes it possible to achieve a desired intensity distribution of the primary light distribution through a suitable design of the deflection reflection surface and/or the collecting reflection surface and/or the light guide body.

The deflection reflection surface can be arranged on the light-guiding body and delimit it at least in sections, which leads to a compact overall structure. The deflection reflection surface can be designed, for example, as a mirrored boundary surface of the light-guiding body. However, it is also conceivable that the deflection reflection surface is arranged on a component that is separate from the light-guiding body, as explained below by way of example.

The photoluminescent element can be arranged directly adjacent to the deflection reflection surface, in particular without a gap. Preferably, the photoluminescent element lies flat against the deflection reflection surface. The deflection reflection surface for a transmitted portion of the laser light that can be irradiated onto the photoluminescence element is thus arranged in the beam path immediately following the photoluminescence element. For example, if the deflection reflection surface is arranged on the light-guiding body itself, the photoluminescent element can be arranged on the deflection reflection surface and integrated in the light-guiding body. For example, the photoluminescent element can then be realized by introducing a photoluminescent dye into a layer of the light-guiding body adjoining the deflection reflection surface. However, it is also conceivable that the photoluminescent element is applied to the deflection reflection surface, for example in the form of a coating. Deviating from the above, however, the deflection reflection surface can also be designed as a reflecting surface of a component that is separate from the light-guiding body, for example a heat sink.

The deflection reflection surface can be designed in such a way that it curves around the photoluminescent element, in particular in a trough shape. Preferably, the deflection reflection surface is dimensioned and arranged such that, viewed from the photoluminescent element, it essentially covers a half-space (i.e. solid angle element with a size of almost 2*Pi). As a result, a large part of the light emitted by the photoluminescent element can be redirected and the efficiency can be increased.

The photoluminescent element may have a plate-like shape. However, a compact shape is also conceivable, for example hemispherical, cone-shaped, cylindrical, truncated cone-shaped or prism-like. With such shapes, a deflection reflection surface that curves around the compact photoluminescent element can be particularly advantageous. The entire primary optical device is preferably designed in one piece as a structural unit. In particular, it is conceivable that the deflection reflection surface and the photoluminescent element are arranged on the light-guiding body, in particular integrated into it. This design as a coherent component can enable simple and cost-effective production and contribute to the construction of a compact headlight unit.

According to an advantageous embodiment, a heat sink is provided, which is arranged in thermally conductive contact with the deflection reflection surface. This is particularly advantageous if the photoluminescent element is arranged directly adjacent to the deflection reflection surface. This can prevent the photoluminescence element and/or the deflection reflection surface from becoming strongly heated by the incident laser radiation during operation of the primary optical device, which can lead to a shortening of the service life of these components. If the deflection reflection surface is arranged on the light-guiding body and delimits it, the heat sink can, for example, be connected in one piece to the light-guiding body or rest against it in a form-fitting manner.

The heat sink can have the deflection reflection surface, which is provided, for example, by a reflective boundary surface of the heat sink. The photoluminescent element can then be arranged directly on the deflection reflection surface of the heat sink. This efficiently avoids unwanted heating of the photoluminescent element due to the irradiated laser radiation and thus the Lifespan of the photoluminescent element increased.

The task set out at the beginning is also achieved by a motor vehicle headlight, which has at least one laser light source, in particular a laser diode, for emitting laser radiation. The headlight also includes at least one photoluminescence element, which is designed and arranged such that the laser radiation that can be emitted by the laser light source hits the photoluminescence element and thereby a mixed light distribution can be emitted using photoluminescence as described above. The motor vehicle headlight can also include a secondary optical device for converting a primary light distribution fed by the mixed light distribution into an emitted light distribution of the headlight. The secondary optical device can be designed, for example, as a collecting reflector and/or projection lens and/or a combination of such components. At least one photoluminescent element of the headlight is contained in a primary optical device according to the invention. During operation of the headlight, the primary light distribution emerges through the light exit surface of the primary optical device, which is optionally converted into the beam light distribution using a secondary optical device.

Depending on the area of application, the beam light distribution to be generated by the motor vehicle headlight should have certain, usually legally specified, characteristic intensity curves. For example, a dimmed light distribution (low beam, fog light) with a characteristic cut-off point or a high-beam light distribution with areas illuminated in a spot-like manner may be desired. The desired beam light distribution is achieved in the headlight according to the invention in that the primary light distribution is converted into the beam light distribution by means of the secondary optical device. The primary light distribution can already have a desired intensity profile, for example light-dark boundary, with this intensity profile being redirected into the beam light distribution via the secondary optical device.

With the design according to the invention, a compact motor vehicle headlight powered by laser light sources can be realized. Due to the primary optical device, the light from the at least one laser light source can be used efficiently to generate the primary light distribution.

The motor vehicle headlight preferably comprises a plurality of laser light sources. It is conceivable that several laser light sources are arranged for irradiating laser light into a common primary optical device, i.e. H. such that they radiate into a common irradiation section of a common primary optical device.

For a further refinement, the headlight can also have a plurality of laser light sources and a plurality of primary optical devices, with one primary optical device each being assigned to at least one laser light source in such a way that its laser light can be irradiated into the irradiation section. A compact and powerful headlight can then be realized in particular by providing a common secondary optical device for the several primary optical devices. The primary light distributions of the various primary optical devices are then converted into an beam light distribution of the headlight by the common secondary optical device.

On the other hand, it is conceivable that a primary optical device of the headlight has at least two different light exit surfaces through which at least two different areas of the primary light distribution can emerge. These separate areas of the primary light distribution can then be redirected by various secondary optical devices into the beam light distribution of the headlight.

Further details and advantageous refinements of the invention can be found in the following description, on the basis of which the embodiments of the invention shown in the figures are described and explained in more detail.

• 1 eine erfindungsgemäße Primäroptikeinrichtung im Längsschnitt;
• 2 eine weitere Ausführungsform einer erfindungsgemäßen Primäroptikeinrichtung im Längsschnitt;
• 3 eine wiederum weitere Ausführungsform einer erfindungsgemäßen Primäroptikeinrichtung im Längsschnitt;
• 4 eine Ausgestaltung der erfindungsgemäßen Primäroptikeinrichtungen mit Lichtleitabschnitten;
• 5 einen erfindungsgemäßen Kfz-Scheinwerfer.

Show it:

• 1 a primary optical device according to the invention in longitudinal section;
• 2 a further embodiment of a primary optical device according to the invention in longitudinal section;
• 3 a further embodiment of a primary optical device according to the invention in a longitudinal section;
• 4 an embodiment of the primary optical devices according to the invention with light guide sections;
• 5 a motor vehicle headlight according to the invention.

In the following description and in the figures, the same reference numbers are used for identical or corresponding features.

The 1 shows a primary optical device 10, which is shown in longitudinal section parallel to a main irradiation direction 12. The primary optical device 10 comprises a light-guiding body 14, which consists of a transparent material suitable for guiding light and has a light exit surface 16. Light guided in the light-guiding body 14 can exit the light-guiding body 14 through the light exit surface 16.

The light-guiding body 14 can be designed as a torus-like rotating body around the main irradiation direction 12 ( 1 ). However, it is also conceivable that the light-guiding body 14 consists of several, non-contiguous body sections, for example in the manner of sectors of a torus-like body of revolution.

In the example shown, the light-guiding body 14 delimits a central transmission opening 18. Laser light bundles L from one or more laser light sources (not shown) can be radiated through this through the light-guiding body 14.

The primary optical device 10 comprises a thermally conductive component that is separate from the light-conducting body 14 and is designed as a heat sink 20 in the example shown. The heat sink 20 has an irradiation surface 22 facing the radiation opening 18. This irradiation surface 22 can be designed as a reflective surface, for example mirrored, and forms a deflection reflection surface 24 of the primary optical device 10.

The deflection reflection surface 24 is covered by a layer-like photoluminescence element 26, by means of which laser radiation can be converted into a mixed light distribution 28 in the manner described above (through photoluminescence and partial scattering). Laser beams can be irradiated onto the photoluminescent element 26 through the transmission opening 18. The transmission opening 18 thus forms an irradiation section 19 of the primary optical device 10.

The light guide body 14 is further delimited by a mixed light entry surface 30 and a collecting reflection surface 32. The collecting reflection surface 32 is designed in such a way that light rays running in the light guide body 14 can be deflected in the direction of the light exit surface 16 by reflection on the collecting reflection surface 32. For this purpose, the collective reflection surface 32 can be designed to be mirrored. However, the collecting reflection surface 32 can also be designed in such a way that total reflection occurs for the light rays of the mixed light distribution in the light-guiding body 14. The collecting reflection surface 32 extends, for example, essentially from the irradiation section 19 to the light exit surface 16.

The mixed light entry surface 30 delimits the light-guiding body 14 on the side opposite the collecting reflection surface 32 with respect to the main irradiation direction 12. The deflection reflection surface 24 and the mixed light entry surface 30 are aligned with one another in such a way that light rays of the mixed light distribution 28 reflected on the deflection reflection surface 24 (as well as light rays which emanate from the photoluminescent element 26 arranged on the deflection reflection surface 24) enter and enter the light guide body 14 through the mixed light entry surface 30 meet the collecting reflection surface 32.

Via the collecting reflection surface 32, the mixed light distribution 28 guided in the light-guiding body 14 is then transformed into a primary light distribution 34 passing through the light exit surface 16.

When used in a motor vehicle headlight, the primary light distribution 34 can be transformed into a desired beam light distribution of the headlight, for example via a secondary optical device (not shown).

Unlike the primary optical device 10, the irradiation section 19 can also be formed by a light coupling surface of the light-guiding body 14. This is the case, for example, with the primary optical device 40 2 the case. This has a substantially disk-like light guide body 14. The light-guiding body 14 can in turn be designed as a rotating body (around the in 2 main irradiation direction 12 indicated by a dashed line), or one or more separate sections of such a rotating body.

The light-guiding body 14 is delimited by a light coupling surface 42, through which laser beams L from one or more laser light sources, not shown, can be irradiated into the light-guiding body 14.

On its side facing away from the light coupling surface 42 with respect to the main irradiation direction 12, the light guide body 14 is delimited by a deflection reflection surface 44. This converges in the direction of the light coupling surface 42 like a cone or prism. The deflection reflection surface 44 is designed to be reflective. Due to the cone-like design, light rays which are coupled into the light guide body 14 through the light coupling surface 42 and run therein to the deflection reflection surface 44 can contribute Reflection on the deflection reflection surface 44 obtains a directional component opposite to the main irradiation direction 12 and radially outward.

The light-guiding body 14 is also delimited in turn by the collective reflection surface 32 which is designed to be reflective (or totally reflective). In the example shown, the collecting reflection surface adjoins the light coupling surface 42 and extends to the light exit surface 16 of the light guide body 14. The light exit surface 16 delimits the light guide body 14 on the side opposite the light coupling surface 42 with respect to the main irradiation direction 12. In the example shown, the light exit surface 16 adjoins the deflection reflection surface 44 of the light guide body 14 and surrounds it.

The deflection reflection surface 44 is covered in the photoluminescence element 40 by a layer-like photoluminescence element 26. This is therefore integrated into the light-guiding body 14, for example by introducing pigments of a photoluminescent dye into the material of the light-guiding body 14.

Through the light coupling surface 42, laser beams L can thus be irradiated onto the photoluminescent element 26, whereby the latter is stimulated to emit a mixed light distribution 28 running in the light-guiding body 14. The light coupling surface 42 thus forms the irradiation section 19 of the primary optical device 40.

Since the photoluminescence element 26 integrated in the light guide body 14 is backed by the reflective deflection reflection surface 44, a portion of the mixed light emitted by the photoluminescence element 16 is redirected to the collecting reflection surface 32 by reflection on the deflection reflection surface 44. A further portion of the light generated by photoluminescence propagates from the photoluminescence element 26 through the light guide body 14 directly to the collecting reflection surface 32.

The mixed light distribution 28 is deflected from the collecting reflection surface 32 to the light exit surface 16 and emerges from the primary optical device 40 through this as a primary light distribution 34.

Viewed from the outside, the light guide body 14 of the primary optical device 40 has a conical or prism-shaped recess delimited by the deflection reflection surface 44. For further refinement, a heat sink 20 made of a thermally conductive material can be arranged in this conical recess, preferably in such a way that the heat sink 20 is in thermally conductive contact with the photoluminescent element 26 via the deflection reflection surface 44.

The 3 shows a further primary optical device 50. The light guide body 14 of this primary optical device 50 essentially has an outer contour corresponding to the primary optical device 40, in particular it is delimited by a light coupling surface forming the irradiation section 19, as well as by a deflection reflection surface 44 opposite the light coupling surface 42 with respect to the main irradiation direction 12. This is in turn conical or prism-shaped and converges towards the light coupling surface 42 to form a cone tip or prism edge. As a result, light rays which strike the deflection reflection surface 44 starting from the light coupling surface 42 can be deflected to the collecting reflection surface 32, which is opposite the deflection reflection surface 44 with respect to the main irradiation direction 12 and is arranged offset radially outwards. Light rays can be directed to the light exit surface 16 via the collecting reflection surface 32.

In the primary optical device 50, the photoluminescent element 26 is not arranged on the deflection reflection surface 44, but directly adjacent to the light coupling surface 42. It is conceivable that the photoluminescent element 26 is designed in a layer-like manner inside the light-guiding body 14 to lie against the light coupling surface 42 which delimits the light-guiding body 14 to the outside.

On the other hand, it is conceivable that the photoluminescent element 26 is designed like a disk and is arranged on the outside of the light-guiding body 14 directly adjacent to the light coupling surface 42.

In any case, in the embodiments mentioned, the photoluminescence element 26 is arranged in the irradiation section 19 in such a way that the photoluminescence element 26 can be excited to emit the mixed light distribution 28 by irradiating laser light bundles L onto the irradiation section 19.

The photoluminescent element 26 is in particular designed to be semi-transparent, so that part of the saved laser beams L is transmitted, and another part is used to emit light of a wavelength different from the laser beams by means of photoluminescence.

If the photoluminescent element 26 is arranged on the light coupling surface 42, the mixed light distribution 28 spreads to the deflection reflection surface 44, from which it becomes the collecting reflection ion surface 32 is deflected and ultimately directed through this to the light exit surface 16.

For a further refinement, the photoluminescent element 26 is arranged inside the light-guiding body 14 immediately adjacent to the light coupling surface 42. The light coupling surface 42 is preferably provided with a reflection coating that is transparent to the wavelength of the irradiated laser light, which has a reflective effect in particular for light with the wavelength that can be generated by photoluminescence. This prevents the portion of the mixed light distribution 28 that is converted by the photoluminescent element 26 into light of a wavelength that deviates from the laser light from emerging at least partially from the light guide body 14 again through the light coupling surface 42.

For a further configuration of a primary optical device according to the invention, a light guide section 62 for guiding the mixed light distribution 28 can be connected in the beam path after the collecting reflection surface 32 (cf. 4 ). The light-guiding section 62 can be connected in one piece to the light-guiding body 14, for example in such a way that in the case of one of the light-guiding bodies 14 described above, a one-piece transition to the light-guiding section 62 takes place via its light exit surface 16. The light-guiding section 62 is preferably delimited by side walls 64, which converge in the direction starting from the collecting reflection surface 32 or the light exit surface 16 (via which the connection to the light-guiding body 14 takes place) to form a light exit surface 16a of the light-guiding section 62. In this respect, in this embodiment, the cross section of the light-guiding section 62 that is effective for light guidance tapers in the direction of the beam path from the collecting reflection surface 32 to the light exit surface 16a. However, an expanding cross section can also be advantageous, with the side surfaces diverging.

However, a design similar to that for the light-guiding section 66, which has at least one further reflection surface 68, possibly in addition to side walls 64, is also conceivable. In such a configuration, the mixed light distribution 28 can be deflected at the further reflection surface 68 after deflection through the collecting reflection surface 32 and propagation into the light-guiding section 66, and exit through a light exit surface 16b of the light-guiding section 66 as a primary partial light distribution 34b. In general, the light guide section 66 adjoining the collecting reflection surface 32 in the beam path can have a further reflection surface in such a way that a desired preferred direction can be specified for the primary (partial) light distribution 34b. It is particularly conceivable that at least two different light-guiding sections 62, 66 are provided, each of which has a light exit surface 16a, 16b through which different primary light distributions 34a, 34b can emerge. Each of the primary light distributions 34a, 34b can, for example, be transformed into different areas of an emitted light distribution via different secondary optical devices (not shown).

The 5 shows a motor vehicle headlight with a plurality of laser light sources 102a to 102b. Furthermore, two primary optical devices 104, 106 are provided, which can be designed, for example, in the manner of the embodiments described above. A secondary optical device 108 is provided downstream of the primary optical devices 104, 106 in the beam path, which in the example shown is designed as a projection lens. A reflector, for example, is also conceivable. Here, an intermediate image can be defined by the primary optical devices 104, 106 in the area of a focal point of the secondary optical device 108. A diaphragm, for example a movable one, can be arranged in the area of the focal point.

In the motor vehicle headlight 100, two laser light sources are assigned to a primary optical device and feed its primary light distribution 34 or 34 '. Both primary light distributions 34, 34 'are projected via the common secondary optical device 108 into an emission light distribution 110 of the motor vehicle headlight 100, the beam light distribution 110 being concentrated around a main emission direction 112 of the motor vehicle headlight 100 in the example shown.

The first primary optical device 104 is assigned to the laser light sources 102a and 102b in such a way that these laser light sources radiate laser light through the irradiation section 19 (depending on the design, transmission opening 18 or light coupling surface 42), which in the manner described by means of photoluminescence into a mixed light distribution and then into the primary light distribution 34 of the primary optical device 104 is converted. In a corresponding manner, the laser light sources 102c and 102d are assigned to the further primary optical device 106 and feed its primary light distribution 34 '.

Claims (7)

Primary optical device (10, 40, 50) for motor vehicle headlights with at least one laser light source, - with a photoluminescence element (26), which is designed in such a way that a mixed light distribution (28) can be emitted by incident laser radiation (L) using photoluminescence, - with an irradiation section (19; 18, 42). which laser light (L) can be irradiated onto the photoluminescent element (26), - with a light guide body (14) having a light exit surface (16) for guiding the light of the mixed light distribution to the light exit surface (16), through which light to form a primary light distribution (34) can exit, the light-guiding body (14) being delimited by at least one collecting reflection surface (32) in such a way that light from the mixed light distribution (28), which runs in the light-guiding body (14), is deflected to the light exit surface (16), with a deflection reflection surface ( 24, 44) is provided, which is designed and arranged in such a way that light from the mixed light distribution (28) which can be emitted by the photoluminescent element (26) can be redirected to the collecting reflection surface (32) by means of the deflection reflection surface (24, 44), characterized in that Photoluminescence element (26) is formed in a layer-like manner on a thermally conductive component that is separate from the light-conducting body (14), an irradiation surface (22) forming the deflection reflection surface (24) being covered by the layer-like photoluminescence element (26), the irradiation surface (22) having a central transmission opening (18), which is limited by the light guide body (14). Primary optical device (10, 40, 50) for motor vehicle headlights with at least one laser light source, - with a photoluminescence element (26), which is designed in such a way that a mixed light distribution (28) can be emitted by incident laser radiation (L) using photoluminescence, - with an irradiation section (19; 18, 42), through which laser light (L) can be irradiated onto the photoluminescent element (26), - with a light guide body (14) having a light exit surface (16) for guiding the light of the mixed light distribution to the light exit surface (16 ), through which light can emerge to form a primary light distribution (34), the light-guiding body (14) being delimited by at least one collecting reflection surface (32) in such a way that light of the mixed light distribution (28), which runs in the light-guiding body (14), is included the light exit surface (16) is deflected, a deflection reflection surface (24, 44) being provided, which is designed and arranged in such a way that light from the mixed light distribution (28) emitted by the photoluminescent element (26) is directed to the by means of the deflection reflection surface (24, 44). Collecting reflection surface (32) can be deflected, characterized in that the photoluminescence element (26) is designed in a layer-like manner in the interior of the light-guiding body (14) to lie against a light coupling surface (42) which delimits the light-guiding body (14) to the outside, the deflection reflection surface (44) being conical or is prism-shaped and converges in the direction of the light coupling surface (42) to form a cone tip or prism edge, the collecting reflection surface (32) being opposite the deflection reflection surface (44) with respect to a main irradiation direction (12) and being arranged offset radially outwards. Device according to one of the preceding claims, characterized in that the collecting reflection surface (32) is arranged on a section of the light guide body (14) which faces the laser light source during operation of the primary optics device, and the deflection reflection surface (44, 24) is arranged on a section of the laser light source during operation of the primary optics device facing away side is arranged. Setup after Claim 2 or 3 , characterized in that the photoluminescent element (26) is arranged on the deflection reflection surface (24, 44), in particular lying flat. Setup according to one of the previous ones Claims 2 until 4 , characterized in that a heat sink (20) is provided, which is in thermally conductive contact with the deflection reflection surface (24, 44). Setup after Claim 5 , characterized in that the heat sink (20) has the deflection reflection surface (24) and the photoluminescent element (26) is arranged on the deflection reflection surface (24). Motor vehicle headlights (100) - with at least one laser light source (102a, 102b, 102c, 102d) for emitting laser radiation; - with at least one photoluminescence element (26), which is designed and arranged in such a way that laser radiation (L) which can be emitted from the laser light source (102a, 102b, 102c, 102d) hits the photoluminescence element (26) and thereby utilizes a mixed light distribution (28). can be emitted by photoluminescence; - and with a secondary optical device (108) for converting a primary light distribution (34, 34') fed by the mixed light distribution (28) into an emission light distribution (110) of the motor vehicle headlight (100), characterized by one comprising the at least one photoluminescence element (26). Primary optical device (104) according to one of Claims 1 until 6 to achieve the primary light distribution (34, 34').

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