LIGHTING DEVICE

Abstract

Illumination device (1) for emitting illumination light, comprising a pump radiation unit (2) with a plurality of pump radiation sources (3a-d), each designed to emit pump radiation in the form of a pump radiation beam (5a-d), a phosphor arrangement (4) with a plurality of regions (4a-c), an optical system (20), and a tilting unit (7) by means of which at least one of the pump radiation beams (5a-d) can be tilted relative to the phosphor arrangement (4), wherein the phosphor arrangement (4) is a rotatably mounted phosphor wheel, and the regions (4a-c) are different, radially offset tracks on the phosphor wheel that are provided concentrically with one another, wherein a first (4a) of the regions (4a-c) of the phosphor arrangement (4) has a first phosphor for at least partial pump radiation conversion, and a second (4b) of the regions (4a-c) differs in its conversion properties from the first region (4a),wherein the at least one pump radiation beam (5a-d) is guided to the first region (4a) in a first position of the tilting unit (7) and to the second region (4b) in a second position, characterized in that the lighting device (1) is configured for operation such that pump radiation is supplied to the first (4a) and the second (4b) region simultaneously, whereupon a first light beam (6a) is emitted from the first region (4a) and a second light beam (6b) also propagates from the second region (4b), which has a different spectral composition than the first light beam (6a), and wherein furthermore, downstream of the phosphor arrangement (4), the first light beam (6a) and the second light beam (6b) are superimposed by the optics (20).

Description

Technical FieldThe present invention relates to a lighting device having a pump radiation unit which has a plurality of pump radiation sources, and having a phosphor arrangement.Prior ArtWith the combination of a pump radiation source of high power density, for example a laser, and a phosphor arranged at a distance therefrom, which emits a conversion light upon excitation with the pump radiation, light sources of high luminance can be realized. It can then either form the conversion light per se for the illumination light (so-called full conversion), or it can form the conversion light in a mixture with proportionally unconverted pump radiation (for example. Blue laser light) forms the illumination light (so-called partial conversion).In the case of light sources which are used in projection applications, it is also known to provide a phosphor arrangement having a plurality of regions which differ in their conversion properties. For this purpose, the phosphors are arranged successively in a plurality of segments on a so-called phosphor wheel; there are, for example, a red, a green and a blue segment. As the phosphor wheel rotates, this phosphor track is moved away under the pump radiation spot, i.e. is sequentially irradiated segment by segment and thus conversion light of different colors is sequentially emitted. In combination with a micromirror arrangement (digital micromirror device, DMD), image generation is then possible, i.e., individual pixels are selectively supplied (or not) with the light of the respective color, the light of different color mixing in the perception of the observer.DE 10 2014 220 101 A1 discloses an optical device comprising a light-imaging module configured to focus light supplied to the light-imaging module in at least one focusing spot, wherein the supplied light comprises at least one predeterminable wavelength; a conversion device having at least one phosphor configured to convert light with the at least one predeterminable wavelength into conversion light, wherein the conversion device is arranged such that the at least one phosphor is arranged in the focusing spot of the light-imaging module, wherein the light-imaging module is configured to generate at least two focusing spots and the conversion device is arranged such that the at least two focusing spots are positioned on the at least one phosphor.DE 10 2012 203 442 A1 discloses an illumination device having a pump laser row, wherein a pump laser beam spot row is moved over a strip-shaped phosphor pattern of a phosphor arrangement with the aid of the pump laser row and a uniaxial tilting mirror.DE 10 2016 217 323 A1 discloses a light module for providing effect light, which has a plurality of excitation beam sources, a phosphor device and a deflection device. The deflection device is designed to direct at least some of the excitation beams coming from the respective excitation radiation sources at least temporarily to different regions of the surface of the phosphor device.SUMMARY OF THE INVENTIONThe present invention is based on the technical problem of specifying a particularly advantageous lighting device.This is achieved according to the invention with a lighting device according to claim 1. This has a plurality of pump radiation sources and a phosphor arrangement having a plurality of regions which differ in their conversion properties. During operation of the lighting device, these different regions (in a specific operating mode, see below) are irradiated simultaneously with pump radiation. A first light beam subsequently emitted from the first region has, corresponding to the different conversion properties, a different spectral composition than a second light beam propagating from a second region of the phosphor arrangement.These light bundles are superimposed by an optical system, i.e. the light is spectrally mixed. In contrast to the phosphor wheel described at the beginning with the sequential sequence and light mixing over time, different color channels can therefore be combined at the same time. This makes it possible to prevent spectral decomposition of the illumination light visible to the human eye, which may result in the case of the sequential sequence (mixing over time), for example, in the case of a rapid movement of the illumination light spot, for example across a stage. When illuminating a film scene or the like, the present illumination device advantageously does not result in separation even if filming is carried out using a camera with a high sampling rate ("slow motion").A further feature of the subject matter of the invention is a tilting unit, by means of which at least one pump radiation beam can be supplied selectively to either the first or the second region. This provides or assists adjustability of the spectral composition of the illumination light. Such a system could be achieved, since a plurality of pump radiation sources are provided, even by way of the actuation thereof alone. Thus, for example, a pump radiation source assigned to the first region could be switched off and a pump radiation source assigned to the second region could be switched on if the spectral ratio is to be shifted in favor of the second region.However, the inventors have found that this results in a relatively low degree of utilization of the individual pump radiation sources over the operation; in the example of precisely the light source assigned to the first region would then be unused. The present approach, on the other hand, allows selective irradiation of one or the other region with the same pump radiation source, which results in a higher degree of utilization. For example, fewer pump radiation sources have to be provided on the whole or they can be dimensioned smaller, which can offer advantages in terms of cost. In addition, the combined use can also result in an overall more compact construction, for example, which can be advantageous, for example, with regard to the integration of the lighting device into a luminaire or the like.The first and the second region of the phosphor arrangement are irradiated simultaneously with pump radiation during operation of the lighting device, that is to say at least in an operating mode. This does not of course exclude that there are other operating modes in which only one of the regions is irradiated in each case or switching back and forth between irradiation of the one and the other region. By simultaneously irradiating the regions, the advantages described in the preceding paragraph already apply.Preferred embodiments are found in the dependent claims and the entire disclosure, wherein the illustration does not always distinguish in detail between apparatus and method or use aspects. In any case, the disclosure is implicit with respect to all claim categories.In general, a light emitting diode (LED) can also be provided as the pump radiation source; a laser diode is preferred. The pump radiation is thus laser radiation, the pump radiation beam bundle is a laser beam bundle. Preferably, at least the pump radiation beam / beams which can be tilted by means of the tilting unit are each a laser beam beam. In general, the pump radiation unit can also have a mixture of laser diodes and LEDs, which can be sorted or fixed, for example, in spectral terms. It can be, for example, possible. Blue laser diodes may be combined with red LEDs, but blue LEDs are also possible alternatively or additionally in general.The pump radiation sources can differ spectrally; preferred wavelengths can generally lie in the UV and / or blue spectral range, wherein in the first-mentioned case a phosphor can convert the UV radiation into blue light, for example. The pump radiation sources can also emit radiation of the same wavelength; particularly preferably, pump radiation sources of identical construction can then also be provided, in particular laser diodes. A preferred wavelength in the blue spectral range can be, for example, at least 450 nm and (independently thereof) at most 480 nm. It is also possible to provide a plurality of pump radiation sources each emitting blue, which differ in their peak wavelengths (have different blue wavelengths), also depending on whether the blue light is used directly or (proportionally) converted. Regardless of their nature in detail, the pump radiation sources are arranged next to one another in the pump radiation unit, preferably in rows and columns, i.e. in the form of a matrix.With respect to the pump radiation sources, generally speaking "radiation", which relates to electromagnetic radiation in the visible spectral range (380 nm to 780 nm), but can also comprise the UV range in particular. Electromagnetic radiation is also guided in the light bundles of the phosphor arrangement, which radiation, because it is illumination, is referred to as "light". This does not of course exclude that radiation components outside the visible range (e.g. infrared components) are also guided in a light beam, but the spectral intensity distribution is preferably in each case at least for the most part in the visible range (of an intensity integrated over all wavelengths, that is to say for example at least 50%, 60%, 70% or 80%).The pump radiation conversion is generally a down conversion; higher-energy (short-wave) pump radiation is converted into, in contrast, lower-energy (longer-wave) conversion light. The phosphor per se can be provided, for example, in particle form, for example applied in the form of agglomerated particles or else embedded in matrix material. However, a phosphor single crystal is also possible, for example.By means of the optics, the light beams emitted from the different regions of the phosphor arrangement are combined or superimposed. Downstream of the optics, the light beams are preferably actually congruent within the scope of technically customary or possible accuracy. In other words, the individual light bundles then completely fill an illumination light light bundle emitted by the illumination device. The light beams thus overlap, for example, not only centrally in the illumination light light beam, but also toward its edge, and therefore also edgewise do not separate.The at least one pump radiation beam can be tilted back and forth between the regions by the tilting unit. Preferably, a plurality of pump radiation beams are tiltable, i.e. also the pump radiation beams of other pump radiation sources, particularly preferably the pump radiation beams of all sources. In general, the tilting unit can also be, for example, a tiltable mounting of the respective pump radiation source itself.In a preferred embodiment, the tilting unit has a displaceably mounted refractive optical element, preferably a lens. The pump radiation beam passing through this optical element can be tilted by displacing the element. Refraction occurs at an entry and / or exit surface of the optical element, wherein an angle that the pump radiation beam has to the irradiated region of the entry and / or exit surface changes with the displacement of the optical element, which brings about the tilting. The displacement of the optical element can be tilting and / or displacement, see below.The optical element is preferably a lens, particularly preferably a collimating lens assigned to the pump radiation source, which is displaceably mounted. Preferably, each pump radiation source is assigned its own collimating lens, wherein generally not necessarily each of them has to be displaceably mounted, in particular not necessarily independently of the other collimating lenses. On the one hand, for example, some of the collimating lenses may be movable together combined to form a group, but on the other hand, each of the collimating lenses may also be movably mounted independently of the others. It is also possible, for example, to displace only collimating lenses arranged on the edge, which can be motivated by tilting the corresponding pump radiation beams or else by improving the beam guidance (it is also possible, for example, to reduce / compensate optical aberrations, which can be of particular relevance in the case of edge-side lenses).In general, a respective collimating lens is assigned to the respective pump radiation source; it is traversed by the respective pump radiation beam and thereby reduces its aperture angle. For example, in the case of a laser diode, the opening angle on the slow and fast axis can be of different sizes (and can be up to 30°). Downstream of the collimating lens, a substantially collimated pump radiation beam may be preferred (aperture angle of 0°). Insofar as reference is generally made to a "lens" within the scope of this disclosure, this can also be a lens system with a plurality of individual lenses arranged in succession. Preferably, a respective collimating lens is actually an individual lens.In general, the respective lens itself can also be tilted in order to tilt the respective pump radiation beam, that is to say the angle between its optical axis and the incident pump radiation beam (specifically its central beam) can be changed. Preferably, the lens is offset (particularly preferably exclusively) perpendicularly to its optical axis, i.e. it is irradiated at different locations by the pump radiation beam in the different positions. A corresponding arrangement can be mechanically simpler than tilting, the lens can be arranged, for example, on or in an axial bearing, and the displacement can be effected, for example, by means of a piezoelectric actuator, a voice coil or other systems known from micro-positioning technology.In general, a tilting unit which offsets a refractive optical element (in particular a lens) can be advantageous with respect to an offset / tilting of the pump radiation source (n) itself, for example, insofar as a component having a lower weight has to be moved in this way. The pump radiation sources are usually housed and / or, because of the thermal household, also provided with or on a heat sink. In comparison thereto, for example, a collimating lens can have a significantly smaller weight, which can enable, for example, a simple mounting or else a less complicated actuator.In a preferred embodiment, not only the first region of the phosphor arrangement has a phosphor, but also the second region, namely a "second" phosphor. The first and the second phosphor differ in their conversion properties, i.e. a first conversion light emitted by the first phosphor upon the pump radiation excitation has a different spectral composition than a second conversion light emitted by the second phosphor. The spectral intensity distributions should in any case not be completely congruent, but can certainly have a certain overlap. Suitable phosphors can have, for example, oxidic or (oxy)nitridic materials, such as garnets, orthosilicates, nitrido(alumino)silicates, nitridoorthosilicates or halides or halophosphates. Specific examples may include doped yttrium aluminum garnets such as YAG:Ce, doped lutetium aluminum garnets such as LuAG:Ce, doped silicon nitride materials such as Eu-doped CaAlSiN3, or the like. Doping materials can generally be, for example, Ce, Tb, Eu, Yb, Pr, Tm and / or Sm. Furthermore, additional dopings are also possible, i.e. co-dopings.In a preferred embodiment, one of the regions of the phosphor arrangement is phosphor-free. The pump radiation beam passes through or passes through this region, i.e. without conversion, pump radiation that is not converted is thus available on this path downstream of the phosphor arrangement, i.e. blue light. For example, in conjunction with a red and a green phosphor in the other regions, an RGB space can thus be spanned. The conversion-free region of the phosphor arrangement does not comprise a phosphor; it can generally also simply be air, but preferably a translucent or transparent material through which the corresponding pump radiation beam passes.In general, it may be preferred that the different regions of the phosphor arrangement are formed integrally with one another, i.e. cannot be separated from one another in a non-destructive manner. The regions are preferably arranged on a common carrier, for example sintered on or otherwise applied, for example adhesively bonded or dispensed. "One-piece" means in this respect not separable from one another without destroying the region / s themselves or the carrier.According to the invention, the phosphor arrangement is a phosphor wheel which is mounted rotatably relative to the pump radiation unit. The regions are different tracks on the phosphor wheel that are radially offset from one another. Although a more complex arrangement is generally also conceivable, the regions are preferably provided concentrically with one another and with the axis of rotation of the phosphor wheel. During operation of the illumination device, the phosphor wheel rotates, whereby the region or regions under the spots of the individual pump radiation beams are moved through. This can be advantageous, for example, insofar as the pump radiation power is thus spread over a larger range over time, which reduces an averaged radiation intensity (i.e., is thermally advantageous).With the tilting of the at least one pump radiation beam, it is possible to switch between the tracks of the phosphor wheel. If one of the regions is provided without conversion (see above), a disk-shaped carrier of the phosphor wheel can be correspondingly slotted, for example, a corresponding segment is preferably filled with a translucent / transparent material. This can be advantageous due to the generation of noise, namely help prevent, for example, a whistle sound that can arise during a slitting operation.In general, the phosphor arrangement can be operated both in reflection and in transmission. In the latter case, the regions are preferably arranged on a common, transparent carrier, for example made of sapphire. During operation in reflection, the regions are preferably arranged on a common reflective carrier, for example made of metal, which can also be additionally mirrored, for example (e.g. with a silver film, in particular high-purity silver). Furthermore, a combination of transmission and reflection is also conceivable, i.e. for example a reflective carrier can be slotted and thus transmissive in regions, for example for the conversion-free channel.In general, a transmission geometry in which the pump radiation is radiated on one side of the phosphor arrangement and the light bundle is discharged on the opposite side can be simpler in design, for example because pump radiation and conversion light guidance are decoupled from one another. A reflection geometry, in which the pump radiation supply and the conversion light discharge are on the same side of the phosphor arrangement, can be advantageous with regard to the thermal household. Since the rear side is not used for guiding radiation, a heat sink, for example, can be arranged there, for which reason reflection geometries can be preferred, in particular in the case of highly loaded phosphors.In a preferred embodiment, the phosphor arrangement has a third region which differs in its conversion properties from the first and the second region. If the first and the second region are provided with a first and a second phosphor (see above), the third region can be free of phosphor, for example. However, it can also be provided with a third phosphor whose conversion light differs in its spectral intensity distribution from the first and the second phosphor.A third light beam emitted from the third region has at least a different spectral composition than the first and the second light beam, the light beams together defining a color space. This means that a respective light bundle (the light guided therein) has a respective color location when viewed in a CIE color diagram ( 1931), and the color locations of the light bundles together span an area in the color diagram (i.e. do not lie on a straight line). A color location of the resulting illumination light, which results from the superposition of the individual light beams, can then be adjusted within the surface (by corresponding adaptation of the proportions that the individual light beams have).In general, the illumination device preferably has a control unit, for example having a logic unit and a driver unit, for example for the pump radiation sources and / or for the tilting unit. Insofar as a specific operation is generally described, this is always also to be read as a disclosure of a control unit set up for this operation. In the aforementioned example ("light beams span color space"), different color locations can be preset, for example, for the illumination light resulting from the superposition of the individual light beams, but the color location can also be freely selectable continuously, on the other hand, for example via a graphical user interface.Independently of this in detail, an adaptation of the portions that the individual light bundles have on the resulting illumination light can be effected on the one hand by means of the tilting unit. This, too, generally does not necessarily have to result in a stepped adaptation, and the tiltable pump radiation beam(s) can / can also be respectively partially irradiated simultaneously on one and the other region of the phosphor arrangement (if the regions directly adjoin one another). Additionally or partly also alternatively to the tilting unit, the output power(s) of the pump radiation source(s) can / can also be adapted. In principle, stepped or even continuous dimming is possible here, in principle from 100% of the nominal current up to 0% or virtually 0%, which is generally phase-modulated, but preferably amplitude-modulated. The dimmability can be limited to low values, for example on the basis of the lasing threshold, such that lower limits can be 5%, 3% or 1%, for example. As in the case of the tilting unit, in particular the displaceable refractive optical elements, the pump radiation sources can be controlled individually or also in groups.An external actuation of the control unit by a user has already been mentioned. Alternatively or additionally, internal operating parameters of the lighting device and / or of a luminaire in which the lighting device is integrated can also be incorporated into the control of the control unit. This can have a safety aspect, for example, so that, for example, in the case of a damaged phosphor arrangement and / or defective pump radiation sources, the emission thereof can be dimmed or completely switched off. On the other hand, however, there may also be feedback from the control unit (and thus the control of tilting and / or pump radiation unit) with downstream effect devices, which alter the illumination light of the illumination device (e.g. filter wheels, gobo wheels, dimming wheels, frosting or prism elements) and which may be integrated, for example, into a corresponding luminaire, in particular a headlight.The actuation of the pump radiation and tilting unit can also be provided separately, i.e. for example via separate components (ICs etc.). On the other hand, (partial) integration is also possible, in particular logic units can preferably be combined in the same component. The control of the pump radiation and tilting unit can then be preceded by a control unit of the luminaire which can also fulfil further functions (for example actuate the optical elements downstream of the lighting device). This control can then also be combined, for example, with an external control unit which, for example, control other lights, for example, via a digital control protocol such as DMX, so that overall a coordinated stage or scene illumination can result.In a preferred embodiment, the illumination arrangement is configured such that illumination light resulting from mixing the first, second and third light beams is white light at least temporarily. White light is therefore emitted in any case in an operating mode. Viewed in the CIE Norm colour diagram (1931), the colour location of the white light should be at a distance from the Planck curve by, for example, not more than 15 threshold value units, increasingly preferably not more than 14, 13, 12, 11 or 10 threshold value units (in each case in terms of magnitude) in the order of naming. A threshold unit (SWE) is defined as SWE = ((u' 2- u' 1)2 · (v' 2- v' 1)2)1 / 2, in the normalized u'(v') space obtained by transformation from the c x / c y- space of the norm chromaticity diagram.In a preferred embodiment, the illumination device has a light mixing means which passes through the light beams downstream of the phosphor arrangement for mixing. This relates in particular to the first and the second light bundle, but if present then also to the third and further light bundle. The light mixing means can generally also be constructed, for example, in the manner of an integrator rod, so that the light of the individual light bundles is guided therein by reflection, in particular total reflection. In the course of the multiple reflections, the light is mixed over the length of the integrator rod. Furthermore, a scattering disk can also be provided, for example, as light mixing means, which can scatter, for example, on account of embedded scattering centers, for example embedded scattering particles (for example titanium dioxide particles), and / or on account of a surface structuring, for example on account of a roughened / etched surface.In a preferred embodiment, a microlens array is provided as light mixing means, which can have efficiency advantages (in comparison with the lens) or can be advantageous on account of its compact size (in comparison with the integrator rod). Such a microlens array can be provided, for example, as a cast part, in particular an injection-molded part, or else as a glass body. The microlens array can be provided in one piece or else in multiple pieces, in particular in two pieces, that is to say from two microlens array parts irradiated sequentially. In the case of a one-piece embodiment, the microlenses are introduced or formed into the incidence and the opposite output surface of the array; preferably, in each case one microlens in the incidence surface and one in the output surface are assigned to one another in pairs. In the case of a two-piece embodiment, the microlenses of the first microlens array part are assigned in pairs to the microlenses of the second microlens array part.In a preferred embodiment, the optics with which the light beams are superimposed comprise a wavelength-dependent mirror. At this light beam, the first light beam is reflected, but the second light beam is transmitted, with the result that the light beams are superimposed. The first and the second light beam are thus guided onto the mirror from different sides and are subsequently superimposed on the mirror on account of the wavelength-dependent reflection / transmission. Downstream of the phosphor arrangement, the light beams can propagate divergently relative to one another (which is preferably even supported with a lens, see below), and are then superimposed with the wavelength-dependent mirror. Upstream of the latter, a further mirror can be arranged in the beam path of one of the light bundles, which mirror reflects this light bundle onto the wavelength-dependent mirror, preferably the first light bundle.In general, a wavelength-dependent mirror can be constructed, for example, as an interference mirror ("dichroic mirror"), that is to say as a multilayer system. This may be provided of at least two dielectric materials differing in refractive indices and arranged alternately in succession in the multilayer system. Of course, even independently of this structure in detail, the wavelength-dependent mirror does not necessarily have to reflect the entire light of the first light bundle and / or transmit the entire light of the second light bundle, but rather can also have certain losses, etc., in this case, for example. Preferably, the larger part of the light guided in the respective light bundle is reflected or transmitted, for example at least 60%, 70% or 80% of the integrated spectral intensity distribution (for technical reasons upper limits can be, for example, at most 99.5% or 99%).In a preferred embodiment, the optical unit has a further wavelength-dependent mirror which is arranged downstream of the first wavelength-dependent mirror. The first and the second light beam are then guided from one side onto the second wavelength-dependent mirror and the third light beam is guided from the opposite side. The light beams are superimposed on the second wavelength-dependent mirror, the second wavelength-dependent mirror is preferably transmissive for the first and the second light beam, but reflective for the third. Preferably, the third light beam can be guided upstream of the second wavelength-dependent mirror via a further mirror and thus reflected towards the second wavelength-dependent mirror (comparable to the first light beam, but preferably via its own mirror).In a preferred embodiment, the optics comprise an axicon which passes through the first and the second light beam, optionally also the third and further light beam. In general words, the axicon is an optical element with which a relative tilting of the light beams can be changed, in particular cancelled out. An angle between the light beams is reduced and the light beams are aligned parallel to one another, in particular, which enables a subsequent superposition and intermixing with the aid of one or more microlens arrays. The light beams can preferably each be collimated by themselves, but in this case tilted relative to one another, fall onto the axicon, for example by arranging a lens upstream of the axicon (see below). Downstream of the axicon, they are then preferably each in each case collimated by themselves, but no longer tilted relative to one another, but rather parallel.The axicon can preferably be an alternative to beam superposition by means of the wavelength-dependent mirror(s). A further possibility for beam superposition can be, for example, a wedge prism and / or a wedge lens. In summary, a wavelength-dependent mirror or a plurality of such mirrors can be provided as a "superposition optics" for superposing the light beams, and / or an axicon and / or a wedge element, such as a wedge prism or a wedge lens.In a preferred embodiment, a lens is arranged downstream of the phosphor arrangement, through which the light beams pass. This is preferably provided between the phosphor arrangement and the superposition optics. Preferably, the lens images the phosphor arrangement at infinity, i.e. the light beams emitted from the different regions are each guided in their own spatial direction and are preferably each collimated in itself. The lens can thus initially move the light bundles further apart, and they can then preferably also strike the superposition optics without overlap (without overlap). This can be advantageous, for example, insofar as sufficient space is available for the superposition optics and thus the actual merging of the light beams.The invention also relates to a method for operating a lighting device disclosed herein, wherein, in a first operating mode, the at least one pump radiation beam is guided to the first region of the phosphor arrangement. In a second operating mode, however, it is then guided to the second region. In general, there may be a plurality of operating modes, wherein pump radiation is supplied to the first and the second region at the same time in at least one of these modes. Preferably, the illumination device emits white light in at least one of the operating modes, see above.For example, an operating mode is also possible in which all pump radiation beams of the active pump radiation sources are guided onto the same region of the phosphor arrangement, so that then, for example, exclusively red or green or blue light is emitted.Alternatively or additionally, two color channels can be controlled in another operating mode, for example. Red and green. By adapting the current supply to the pump radiation sources, the overall resulting color location can then be shifted between red and green, for example, on a straight line. In the case of white light, which is preferably composed of at least three channels (red, green, blue), wherein additional channels are also conceivable (e.g. yellow), the white point can preferably be set via the control of the pump radiation sources and / or the tilting unit.The invention also relates to the use of a lighting device disclosed herein, in particular in a luminaire, for example a headlight. This can be used for stage or scene illumination, i.e. in the theater or also movie, television and show range. Illumination of concert platforms, etc., is also possible. An operation is preferred in such a way that the illumination light which results from the superposition of the light beams is white light at least temporarily. However, motor vehicle or automobile applications, applications in architectural lighting (architectural lighting) or applications for medical light sources are generally also possible, for example.In addition to the pump radiation sources which supply the phosphor arrangement with radiation, the pump radiation unit can also have one or further radiation sources which can assume other tasks. These radiation sources can be used, for example, for measurement or analysis purposes, for example for distance and / or speed measurements, for example according to the LIDAR principle, in particular in the case of an illumination device provided for exterior motor vehicle illumination. With a view to effect illumination, for example, UV radiation sources can also be additionally provided (not for supplying the phosphor arrangement) in order to generate further effects, such as fluorescence, phosphorescence or black light effects.Brief Description of the DrawingsThe invention is explained in more detail below on the basis of an exemplary embodiment, wherein the individual features within the scope of the subordinate claims can also be essential to the invention in a different combination and also are not differentiated in detail between the different claim categories.The detailed figure shows FIG. 1 shows a part of a lighting device according to the invention, namely a pump radiation unit and a phosphor arrangement operated in transmission; FIG. 2 shows, following the arrangement according to FIG. 1, a first possibility for superimposing the light beams emitted by the phosphor arrangement; FIG. 3 shows a second possibility for superimposing the light beams as an alternative to FIG. 2 ; FIG. 4 shows, as an alternative to the arrangement according to FIG. 1, a pump radiation unit in combination with a phosphor arrangement operated in reflection; FIG. 5 shows a phosphor arrangement designed as a phosphor wheel in a plan view.Preferred Embodiment of the InventionFIG. 1 shows a part of an illumination device 1 according to the invention in a schematic section or a sectional side view, namely a pump radiation unit 2 having a plurality of pump radiation sources 3 and a phosphor arrangement 4, specifically a phosphor wheel. The phosphor wheel is divided into a plurality of regions 4 a- c, wherein a first region 4 aand a second region 4 bare each provided with a phosphor and these phosphors differ in their conversion properties. A third region 4 cis phosphor-free, namely formed as a transmissive window.Laser diodes are provided as pump radiation sources 3 in the present case (cf. the introduction to the description with regard to alternative possibilities), which are arranged in the form of a matrix, that is to say form a 4x4 array. During operation, the pump radiation sources 3 emit pump radiations, in the present case blue light, in a respective pump radiation beam bundle 5 a- d. The pump radiation beams 5 a- dare guided to the phosphor arrangement 4, in each case to one of the regions 4 a- c. The phosphor arrangement 4 is operated in transmission in the present case, and light beams 6 a- care therefore discharged on an opposite side in response to this excitation.In the first region 4 a, the blue light is converted into red light, for example with an orthosilicate phosphor; in the second region 4 b, the incident blue light is converted into green and yellow-green light, for example with a cerium-doped yttrium aluminum garnet such as YAG:Ce as phosphor. The third region 4 ctransmits through the blue light without conversion, and three light bundles 6 a- cof the colors red, green and blue are thus present downstream of the phosphor arrangement 4. As explained in detail with reference to FIGS. 2 and 3, these light beams 6 a- care then superimposed further, so that, for example, in a mixture, they are mixed. White light can result.The illumination device 1 further comprises a tilting unit 7, namely an arrangement of a plurality of collimating lenses 8 a- d. Each of the pump radiation sources 3 a- dis assigned a respective collimating lens 8 a- d, with which the respectively slightly divergently emitted pump radiation is collimated (not shown in detail). These collimating lenses 8 a- dare displaceably mounted in the tilting unit 7, namely each displaceably perpendicular to its optical axis (i.e. in FIG. 1 each upwards and downwards, cf. also the arrows).If the first pump radiation source 3 awith the collimating lens 8 ais now considered by way of example, the first pump radiation beam bundle 5 acan be tilted by displacing this collimating lens 8 a. In the situation shown, the collimating lens 8a is offset downwards (which is indicated by the arrow). If the collimating lens 8 ais moved upwards again, the first pump radiation beam 5 amove the phosphor arrangement 4 in a less tilted manner, i.e. it no longer falls onto the third region 4 cbut onto the second region 4 b. If the collimating lens 8 ais displaced still further upwards, so that the first pump radiation beam 5 atransmits the first collimating lens 8 ain a manner offset again with respect to its optical axis, the first pump radiation beam 5 aadears finally onto the first region 4 aof the phosphor arrangement 4.The remaining pump radiation beams 5 b- dmay be tilted in an analogous manner with the remaining collimating lenses 8 b- d, so that an irradiation of the regions 4 a- cmay be selectively adjusted. Thus, for example, a color location of the resulting illumination light downstream of the illumination device 1 can be adjusted. Since the individual pump radiation sources 3 a- dare not simply connected in or disconnected here, overall a high degree of utilization of each individual pump radiation source 3 a- dis obtained (cf. also the comments in the introduction to the description in detail).There can then be in detail very different operating modes, especially since the pump radiation unit 2 has a total of 16 pump radiation sources 3, that is to say there are 16 pump radiation beams 5 (of which only four can be seen). Thus, for example, in certain operating modes in which "single-color" light is to be emitted, all 16 pump radiation beams 5 can be guided onto exactly one of the regions 4 a- c. Furthermore, one or some of the pump radiation sources 3 can also be switched off, wherein the remaining subset is then assigned exactly to one of the regions 4 a- c. In other operating modes, two of the regions 4 a- cor also all three regions 4 a- cmay be irradiated, wherein a further differentiation with respect to the number of pump radiation sources 3 assigned to each region 4 a- cis then also possible (e.g. 5- 5- 5- 6, 4- 4, 8, etc.). In addition, in this case too, once again only some of the pump radiation sources 3 can be irradiated, that is to say a subset can be divided correspondingly.Arranged downstream of the phosphor arrangement 4 is a lens 10 which images the phosphor arrangement 4 to infinity. Each of the light beams 6 a- cis collimated by itself, but the light beams 6 a- cextend in different spatial directions 11 a- c.FIG. 2 shows subsequently, i.e. as a further part of the illumination device 1, an optical unit 20 with which the light beams 6 a- care superimposed ("superimposing optical unit"). The optical unit 20 is constructed from a wavelength-dependent mirror 21 and a further wavelength-dependent mirror 22. In the present case, these are separate elements, but an integral embodiment as a so-called dichro cross or X cube would also be possible. The first light beam 6 aand the second light beam 6 bare guided from different sides onto the first wavelength-dependent mirror 21, wherein the first light beam 6 ais then reflected there and the second light beam 6 bis transmitted. The first and the second light beam 6 a, bare superimposed downstream of the wavelength-dependent mirror 21.In this form, the first and the second light beam 6 a, bappear onto the further wavelength-dependent mirror 22, onto which the third light beam 6 cis guided from the other side. The further wavelength-dependent mirror 22 is reflective for the third light beam 6 c, but transmissive for the first and second light beams 6 a, b, such that all three light beams are superimposed downstream of the further wavelength-dependent mirror 22 (for illustrative reasons, a certain offset is shown, but within the scope of technically customary accuracy the light beams 6 a- care congruent).The first light beam 6a is guided onto the first wavelength-dependent mirror 21 via a further mirror 23, which is designed as a metallic mirror. The third light beam 6 cis guided onto the second wavelength-dependent mirror 22 via a mirror 24, which is likewise embodied as a metallic reflector.Downstream of the optics 20, a light mixing means 25 is provided, namely a one-piece microlens array. This is traversed by the superimposed light beams 6a-c and creates a further mixing within the resulting beam. The present illustration is schematic, in practice the microlenses 25a,b formed on the incidence and output sides are significantly smaller in relation to the cross section of the beam.FIG. 3 shows an alternative possibility for superimposing the light beams 6 a- c, again proceeding from the situation according to FIG. 1. The light beams 6 a- care each collimated by themselves downstream of the lens 10, but tilted relative to one another (results from the imaging into infinity, see above). In the variant according to FIG. 3, the optical unit 20 has an axicon 30 for superposition, on which the light beams 6 a- cwhich are tilted with respect to one another strike. When the axicon 30 is passed through, they are then aligned parallel relative to one another, but remain collimated in each case by themselves.The light beams 6 a- care then incident in this form in a collimated manner, i.e. in each case separately and parallel relative to one another, on the downstream microlens array 25. Within a resulting overall bundle, the light of different colors originating from the individual light bundles 6 a- cmay then be intermixed such that, graphically speaking, the colors are each uniformly distributed over the cross section of the overall bundle.FIG. 4 shows an alternative possibility for the construction of a lighting device 1 according to the invention, and specifically analogously to FIG. 1 again only a part thereof. In contrast to the arrangement according to FIG. 1, the phosphor arrangement 4 is operated in reflection in this case. The regions 4 a- care thus arranged on a reflective carrier 40, whereas in the variant according to FIG. 1, a sapphire carrier, for example, can be provided. In general, parts with the same or comparable function are provided with the same reference numerals; reference is made to the description relating to FIG. 1 in particular with regard to the pump radiation unit 2 and the tilting unit 7.According to FIG. 4, the phosphor arrangement 4 is operated in reflection, the pump radiation beams 5 a- dare therefore supplied on the same side on which the light beams 6 a- care also discharged. In order to decouple the pump radiation guide from the conversion light guide, a dichroic (wavelength-dependent) mirror 41 is provided. This is transmissive for the pump radiation, but reflective for the conversion light. Consequently, the light beams 6 a- cwhich are discharged from the regions 4 a- cthereof at the phosphor arrangement are reflected from the beam path of the pump radiation (upward in FIG. 4 ).The pump radiation here is UV radiation. This is then wavelength-converted not only for the red and green channels, but a phosphor is also provided for the blue channel. Therefore, the pump radiation and the light beams 6a-c all have different wavelengths and the decoupling just described is possible.Alternatively, the pump radiation can also be blue radiation. In this case, instead of a phosphor, a phosphor-free region is provided for the blue channel, which region transmits the pump radiation. With the aid of deflection mirrors, the transmitted radiation is deflected in such a way that it again impinges on the dichroic mirror 41 from the same side as the pump radiation beam bundles 5 a- d(this concept is known in the prior art as "blue loop" and is described, for example, in DE 10 2012 220 570 A1 and DE 10 2012 223 925 A1). The dichroic mirror 41 is designed in this case such that it transmits blue radiation, but reflects the conversion radiation emitted by the phosphor regions. In this way, decoupling of the individual color channels is also possible with blue pump radiation. Furthermore, the light beams 6 a- cmay then be superimposed analogously to the above description, for example using dichroic mirrors 21, 22 (FIG. 2 ) or using an axicon (FIG. 3 ).Both in FIG. 1 and in FIG. 4, the phosphor arrangement 4 is in each case designed as a phosphor wheel which is mounted rotatably about an axis of rotation. The regions 4 a- care concentrically arranged phosphor tracks, which can be seen in the plan view according to FIG. 5. The axis of rotation 50 is perpendicular to the plane of the drawing; concentric rings (the phosphor tracks or the phosphor-free slot) can be seen. With the tilting unit 7, a respective pump radiation spot 51 can then be tilted back and forth between the regions 4 a- c, from top to bottom in FIG. 5.LIST OF REFERENCE CHARACTERS1 Illumination device 2 Pump radiation unit 3 a- dPump radiation sources 4 Phosphor arrangement / phosphor wheel 4 a- cto first to third regions 5 a- dPump radiation beam bundle 6 a- cLight bundle 7 Tilting unit 8 a- d Koll lenses 9 Converging lens 11 a- c Raumrichtungen directions 20 Optics (superposition optics) 21 Wavelength-dependent mirror 22 Further wavelength-dependent mirror 23 Further mirror (metallic) 24 Further mirror (metallic) 25 Light mixing means 25 a, b Mikrolinsen lenses 30 Axicon 40 Carrier 41 Mirror (wavelength-dependent) 50 Axis of rotation 51 Pump radiation spot

Claims

Illumination device (1) for emitting illumination light, having a pump radiation unit (2) having a plurality of pump radiation sources (3a-d) which are each designed to emit pump radiation in the form of a pump radiation beam (5a-d), a phosphor arrangement (4) having a plurality of regions (4a-c), an optical unit (20), and a tilting unit (7) by means of which at least one of the pump radiation beams (5a-d) can be tilted relative to the phosphor arrangement (4), wherein the phosphor arrangement (4) is a rotatably mounted phosphor wheel, and the regions (4a-c) are different tracks on the phosphor wheel which are radially offset with respect to one another and are provided concentrically with one another, wherein a first (4a) of the regions (4a-c) of the phosphor arrangement (4) has a first phosphor for at least partial pump radiation conversion and a second (4b) of the regions (4a-c) differs from the first region (4a) in its conversion properties, wherein the at least one pump radiation beam (5a-d) is guided to the first region (4a) in a first position of the tilting unit (7) and to the second region (4b) in a second position, characterized in that the lighting device (1) is configured for operation in such a way that pump radiation is simultaneously supplied to the first (4a) and the second (4b) regions, whereupon a first light beam (6a) is emitted from the first region (4a) and a second light beam (6b) which has a different spectral composition than the first light beam (6a) also propagates from the second region (4b), and wherein the first light beam (6a) and the second light beam (6b) are additionally superimposed with the optical unit (20) downstream of the phosphor arrangement (4).Illumination device (1) according to Claim 1, in which the tilting unit (7) has a displaceably mounted, refractive optical element which passes through the at least one pump radiation beam bundle (5a-d), preferably a collimating lens (8a-d), wherein the at least one pump radiation beam bundle (5a-d) can be tilted by displacing the optical element.The lighting device (1) according to claim 1 or 2, wherein the second region (4b) of the phosphor arrangement (4) comprises a second phosphor whose conversion properties differ from those of the first phosphor.Lighting device (1) according to one of the preceding claims, in which at least one (4c) of the regions (4a-c) of the phosphor arrangement (4) is free of phosphor, that is to say pump radiation is emitted from the at least one region (4c) in a conversion-free manner in a light beam (6c) which is assigned to the at least one region (4c).Lighting device (1) according to one of the preceding claims, in which the phosphor arrangement (4) has a third region (4c) which differs in its conversion properties from the first (4a) and the second region (4b) in such a way that a third light beam (6c) emitted from the third region (4c) has a different spectral composition than the first (6a) and the second light beam (6b), wherein the first (6a), the second (6b) and the third light beam (6c) span a color space with one another when viewed spectrally.The lighting device according to claim 5, which is configured such that the illumination light resulting from mixing the first (6a), second (6b) and third light beam (6c) is white light at least temporarily.Lighting device (1) according to one of the preceding claims, having a light mixing means (25) which pass through the first light beam (6a) and the second light beam (6b) downstream of the phosphor arrangement (4) for mixing.The lighting device (1) according to claim 7, wherein the light mixing means (25) is a microlens array.Illumination device (1) according to one of the preceding claims, in which the optical unit (20) has a wavelength-dependent mirror (21), on which the first light bundle (6a) is reflected and the second light bundle (6b) is transmitted and the light bundles (6a, b) are superimposed in the process.Illumination device (1) according to Claim 9 and Claim 5 or 6, in which the optical unit (20) has a further wavelength-dependent mirror (22) which is arranged downstream of the first wavelength-dependent mirror (21) and which transmits the first (6a) and the second light bundle (6b), but at which the third light bundle (6c) is reflected and the light bundles (6a, b, c) are superimposed in the process.Illumination device (1) according to one of the preceding claims, wherein the optics (20) comprise an axicon (30) which passes through the first (6a) and the second light beam (6b), wherein an angle between the light beams (6a, b) is reduced.Illumination device (1) according to one of the preceding claims, having a lens (10) which is arranged downstream of the phosphor arrangement (4) and which passes through the light bundles (6a, b), wherein the lens (10) preferably images the phosphor arrangement (4) to infinity.Method for operating a lighting device (1) according to one of the preceding claims, in which the lighting device (1) is operated in different operating modes, wherein pump radiation is supplied simultaneously to a first (4a) and a second (4b) region and the at least one pump radiation beam (5a-d) is guided to the first region (4a) in a first of the operating modes and is guided to the second region (4b) in a second of the operating modes.Use of an illumination device (1) according to one of Claims 1 to 12 for illumination, in particular in a headlight and / or for stage or scene illumination and / or for at least temporary illumination with white light.

Images