WO2018007117A1

WO2018007117A1 - Lighting device comprising a light source for emitting illumination light

Info

Publication number: WO2018007117A1
Application number: PCT/EP2017/064642
Authority: WO
Inventors: Stephan Schwaiger; Ricarda Schoemer; Oliver Hering
Original assignee: Osram Gmbh
Priority date: 2016-07-04
Filing date: 2017-06-14
Publication date: 2018-01-11
Also published as: DE102016212086A1

Abstract

The invention relates to a lighting device comprising a light source (2), a micro-mirror array that includes a plurality of micro-mirror actuators (1) arranged in the form of a matrix, and an illuminating lens system (6); during operation, illumination light (23) emitted by the light source (2) is directed onto and reflected by the micro-mirror actuators (1) of the micro-mirror array, and with the reflection in the time integral, an ON light beam (8) is reflected to an illumination application via the illuminating lens system (6) by the micro-mirror actuators (1) in a tilted ON position, and an OFF light beam (9) is reflected to a location next to the illuminating lens system (6) by the micro-mirror actuators (1) in a tilted OFF position, at least some of the illumination light contained in the OFF light beam being directed back to the light source (2).

Description

LIGHTING DEVICE WITH A LIGHTING SOURCE FOR THE LIGHTING OF LIGHTING LIGHT

DESCRIPTION Technical area

The present invention relates to a Beleuchtungsvor ^¬ direction with a light source for emission of an illumination light, a micromirror array and a Be ^¬ illumination optics.

State of the art

A micromirror array is constructed from a multiplicity of micromirrors arranged in the form of a matrix which, as actuators, can be switched independently of one another and thus tilted. In projection applications, such micromirror arrays are used as imagers. Thus, corresponding to each digital micromirror device to a pixel, wherein, depending on the tilting position of the falling thereon in respective time points of light be ^¬ certain color (eg. As red, green and blue) is forwarded to the imaging, or not.

Presentation of the invention

The present invention is based on the technical problem of specifying a particularly advantageous lighting device.

According to the invention this object solves a Beleuchtungsvor ^¬ direction with a light source for emission of an illumination light, a micromirror array with a Variety of matrix-like arranged micromirror actuators and illumination optics, wherein the light source and the micromirror array are arranged to each other, that is guided by the light source in operation, a supply beam with the illumination light on the micro ^¬ mirror actuators of the micromirror array and reflected at this wherein the reflection in time integral union ^¬

a one-beam is reflected from the micro-mirror actuators in a respective one-tilt position beyond the illumination optics to a lighting application, and

an out-beam is reflected by the micro-mirror actuators in a respective off-tilt position adjacent to the illumination optics,

characterized in that a part of the illumination light contained in the radiation beam is at least partially guided back to the light source. Preferred embodiments can be found in the dependent claims and the entire disclosure, wherein the presentation does not always differentiate in detail between device and process or use aspects; In any case, implicitly, the disclosure must be read with regard to all categories of claims.

The illumination device according to the invention thus has a light source and a micromirror array (hereinafter also referred to as "array"), with the supply beam falling with the illumination light from the light source onto the array ") the illumination light is reflected So, each micro-mirror actuator a respective sub-beam. Depending on the tilt position of the respective micromirror actuator, the respective sub-beam is reflected via the illumination optics for illumination application (on-tilt position) or next to the illumination optics (off-tilt position), so it is not supplied to the illumination application in the latter case. About the tilted position of the actuators a light distribution in the far field an oscillating back and heart valves possible, for. Example by dimming states can thus be set specifically (but a respective tilt should not there be taken permanently ^¬ way, it is also such. As to realize, see below in detail). One possible area of application is an adaptive street lighting with a motor vehicle headlight, see also below in detail.

All the sub-beams which are reflected from the Ak ^¬ motors respectively in one-tilted position, the "A bundle of rays"forms; the sum of all reflected by the actuators in respective off-tilted partial radiation beam forms the off-beam. The input beam and the out beam respectively result in the temporal integral, because typically not all the actuators are simultaneously in the same tilt position or the actuators are also operated in an oscillating manner in general / or second range and / or range of minutes and / or longer. in the projection area (video projection, etc.) are micro mirror arrays used as the imager, see above. The off-beam is thereby "destroyed" in a sublingually ^¬ BER (beam dump). In the inventive lighting device, however, at least a part of the illumination light included in the initial beam is preferably guided (nachfol ^¬ quietly only "light") back to the light source. This is advantageous in that it then from there depending ^¬ denfalls anew in proportion to but this can ultimately be used for illumination purposes (this part of the illumination light is "recycled", also referred to below as "recycle illumination light") Preferably, the recycled illumination light arrives on the same path as the original emitted illumination light the array, ie in the feeding beam. As will be explained in detail which comes to the light source returned illumination light preferably in the opposite direction back to the light source, thus requiring the recycling there ei ^¬ ne reversal of direction. This can be particularly great in the case of ei ^¬ ner below in Individual n explained light source with a stimulated with pumping radiation phosphor element be possible because in this the illumination light ge scattered ^¬ or absorbed and re-emitted and proportionally with this scattering undergoes a reversal (again to the array).

In general, however, such a recycling with direction reversal but, for example, in the case of a halogen or gas discharge lamp as a light source may be possible; Namely, the returned illumination light, for example. Reflected on egg ^¬ nem reflector of the lamp and so brought into the feed beam and thus recycled. Furthermore, absorption is also possible here or the light does not necessarily have to be scattered only (for example in the case of a light source) Halogen lamp, the wire can be heated by reflected IR light and this power must then no longer be supplied electrically). Incidentally, the illumination light can be lead to the light source also dropped so that it is already arrive there with a directional ^¬ component, which coincides with a main emission direction of the originally taken away from the light source illuminating light.

Thus, the illumination light in general, for example, by an optical fiber, such as a glass fiber, are returned to the light source, whereby the Rich ^¬ tion component of the illumination light at the Lichtquel ^¬ le relatively freely choose (by a corresponding orientation of the optical fiber output, or also by additional optical elements, such as, for example, mirrors and / or dichroic elements and / or lenses and / or further light guides). The light guide may, for example, be associated with a wavelength-dependent mirror, which may then, for example, be transmissive and reflective for the conversion light in the case of a light source with a phosphor element, so that only the pump radiation is returned to the phosphor element.

The micro mirror array, the illumination optics is assigned such that the gelaktoren of different Mikrospie- in one tilting position passes through the illumination optics illuminating light guided in different spatial directions ^¬. The light distribution in the spatial space in the array plane is thus translated into a light distribution in the angular space of the far field. By selectively turning on / off a respective actuator can accordingly a respective spatial direction or a solid angle range are selectively supplied with illumination light, or not.

From one of the illumination optics to-reach maximum beam downstream can be varied at hinzu- solid angle ranges and disconnection, which can be used eg. To adapti ^¬ ven road illumination. One of eg. A camera system of the motor vehicle (vehicle) erfass- tes, preceding vehicle or oncoming vehicle can thus, for example. Be specifically excluded from the cone of light, so by the respectively associated micro mirror actuators turned off are ge (in a corresponding tilt position) ^¬ introduced. This is intended to illustrate an advantageous field of application which is also preferred in this respect, but does not limit the idea of invention in its generality.

The illumination optics can generally also have a reflector; preferred is an exclusively refractive illumination optics. In general, a non-imaging illumination optics is conceivable, but preferably it is imaging. The illumination optics may, for example, comprise a lens, preferably a converging lens, wherein the lens may also be constructed in the manner of a lens system from a plurality of individual lenses (arranged successively with respect to the fluoroscopy). Before ^¬ an arrangement Trains t such that the Beleuchtungsop ^¬ tics, maps the micromirror array, so the actuators into Unend ^¬ Liche.

The "micromirror array" (also Digital Micromirror Device, DMD) can, for example, at least 10, 100, 500, 1,000, 5,000, 10,000 or 30,000 micromirror actuators and (independently) z. B. no more than lxlO ⁸ _' lxlO ⁷ or lxlO have ⁶ micro-mirror actuators (each in the order of naming increasingly preferred). The micro-mirror actuators are preferably part of the same semiconductor component (chips). They are not necessarily switchable completely un ^¬ depending on each other, but can, for example, already be summarized on the chip side in groups. Thus, for example, a plurality of juxtaposed micro-mirror actuators can collectively supply a spatial angle range, or not, that is, all of them can then be switched on or off. Also with regard to certain operating modes, such. As high beam, low beam, daytime driving ^¬ light, etc., an already original group-wise summarizing is possible.

In a preferred embodiment, a recycling mirror is provided on which the illumination light guided in addition to the illumination ^{top is} reflected at least partially back to the light source. The recycling levels may also generally have a diffuse or specular-diffuse reflecting reflection surface before Trains t ^¬ it is specular reflective. A curved reflection surface may be preferred, particularly preferably a concavely curved reflection surface; it is, for example, a spherical curvature possible, it is preferably aspherical ^¬ , about ellipsoidal or freely shaped, each at least partially.

In a preferred embodiment, the illumination light reflected at the recycling mirror is guided back to the light source via the micromirror array. So far in general, therefore, a separate path conceivable If, for example, an additional mirror is adjacent to the array, the light is preferably directed back and forth along the same path (from the light source to the recycling mirror and back). This may, for example, be advantageous insofar as the same optical components are used, ie, for. B. no additional mirror next to the array is necessary, which can offer advantages in terms of cost and also can help increase the depth of integration and may also be in terms of space of interest. The inventors have found that in correspondence over the array run illuminating light may be disadvantageous in the aforementioned projection applications possibly because increased so flexen the likelihood of un ^¬ desired in the one-ray beam entered Större-. Such reflections can generally take place not only at the Ak ^¬ tors in itself, but especially at suspension bridges, the chip metallization or surface. In any case, in the present case in particular re ^¬-relevant headlamp applications, particularly in the automotive field, but said efficiency advantage outweighs a possibly somewhat reduced contrast.

In a preferred embodiment, a recycling optics at ^¬ is arranged between the array and the recycling mirror which, for example, to reflect a reflection surface of the mirror recycled to the array or the initial radiation beam and can focus only what possibly a smaller Recycling mirror allows. It may, for example, a recycling possible. 1: 1 may be preferred, ie a IRL illustration of the array (or a respective Mikrospie- gels) through the recycling mirror back to the Ar ^¬ ray (or the respective micro-mirrors). But it can On the other hand, it may also be preferable to focus on (a) particular area (s). Thus, for example, outside areas of the array can be rather dark from the point of view of the illumination ^application , ie the actuators are therefore switched off more often; to this light to recycle effectively, it is ideally in the center of the light source zurückreflek ^¬ out (not necessarily the center of the array).

Preferably, a converging lens as a recycling optics, which may be constructed, for example, as a lens system of a plurality of individual lenses (with respect to the fluoroscopy on ^¬ successively arranged). Preferably, the ge ^¬ entire from the array to the recycling mirror and back led illumination light passes through the recycling optics, so it passes through ^¬ se during a recycling process twice. The recycling optic is preferably antireflective. In general, however, a separate recycling optics is not compulsory and can be light-formed, for example, with a concave mirror as a recycling mirror, which may therefore be provided as an alternative to, but also in combination with a recycling optic. In particular, as far as the array can be considered as approximately punctiform, a spherical concave mirror is sufficient; but it can also be provided a free-form mirror.

A preferred embodiment relates to an adjustable in its reflection behavior recycling levels. To this extent, "adjustable" may mean, for example, that the spatial distribution of the reflection is variable and / or the spectral composition of the reflected illumination light is variable, for example via a wavelength-selectively variable reflectance. conditions of variable reflectance. Various options for implementation are discussed in detail below; In general, one approach may be to provide a level of recycling with varying reflection properties over its total reflection area. Depending on requirements, one or the other area of the total reflection surface can then be used (preferably by displacing the mirror).

With the adjustable recycling mirror can also be the properties of the then ultimately (taking into account the recycled illumination light) through the Be ^¬ lighting optics for lighting application guided illumination light, namely either change targeted or keep constant (by compensation). This may in particular relate to the spectral properties, for example the color locus. In the case of a light source with a luminescent ^element, for example, this can lead to ei ^¬ ner shift due to recycling, because recycling can change the ratio of pumping radiation to conversion light. Thus, for example, in the case of a phosphor element operated in partial conversion, white illumination light can be set by a mixture of proportionally unconverted pump radiation (blue light) and yellow conversion light, wherein the recycling can shift the ratio in favor of the latter (the pump radiation still contained in the returned illumination light is at least proportionately converted during recycling, which changes the ratio). The adjustable recycling level is thus also to be seen in particular in such a context. In a preferred embodiment, the adjustable reflection behavior is reacted with an at least partially reflective surface klappba ^¬ ren. Thus, for example, the recycling mirror may also be a micromirror array, with regard to its possible embodiment, reference is expressly made to the above disclosure. However, in principle macroscopic mirror ^elements are also conceivable (which, for example, are not part of a common chip), which each form part of the reflection surface and are switchable / foldable such that in each switching / folding state the illumination light is emitted from a respective one Mirror element is guided back to the light source and not in another switching / folding state. There are also other switching / folding states possible, which, for example, the place to which each ^{¬ is} reflected back, can be varied. The same functionality could of course also be achieved with a micromirror array as a recycling mirror, with a finer spatial resolution (an array as a recycling mirror would preferably be arranged very close to the actual array or in conjunction with a mapping of the actual array onto the array Recycling level reali ^¬ siert).

In general, the "at least partially foldable" means that a respective reflection surface area can be pivoted or tilted about at least one axis of rotation micromirror arrays. In a preferred embodiment, the recycling mirror is displaceably mounted to the off-beam and can be set by the offset the reflection behavior. In general, this could be combined with a loading rich as folding reflecting surface is preferably precisely one of the two alternatives reali ^¬ Controlling (also for reasons of complexity). In the "ver ^¬ settable" storage is not necessarily the Posi ^¬ tion of the recycling mirror also a rotatable mounting of whole needs to be changed, it is for example. Possible (a filter equivalent), it being possible to switch between the Versetzstellungen with the rotational movement. Likewise, but is also a displaceable mounting possible, preferably with a sliding direction, the obliquely sawn Sonders preferably perpendicular, is a main direction in which the illumination light strikes the recycling levels. Alternatively, a Va ^¬ riation could in general not (only ) by displacing the recycling mirror, but alternatively / additionally also by tilting and / or rotating and / or shifting a recycling optics.

In general, in the context of this disclosure, a "main direction" of a respective beam (or considered part thereof) as an average of all direction vectors along which propagate in the respective beam (or part thereof) the radiation or the light, wherein is weighted with this averaging each ^¬ the direction vector associated with the beam intensity him. preferred is a linearly displaceably mounted recycling mirror, for example via a linear motor / -aktor overall exaggerated. As an alternative to the oblique / vertical displaceability, displacement along the main direction would generally also be conceivable; in combination with convergent / divergent illuminating light striking the recycling mirror, the respective illuminated area thereof can be varied, which, combined with reflection properties differing over the reflection surface, results in a changed reflection behavior.

In a preferred embodiment, a displaceable filter is provided and the displacement of the filter can be used to set the spectral properties of the illumination light reflected from the illumination application. This adjustability does not have not ^¬ sarily mean a change but can also be made in a constant hold, see. the above statements. The filter may, for example, between the array and the mirror or at a recycling Lö ^¬ solution, wherein the recycled light is not fed back via the Ar ^¬ ray, between the array and the light source may be arranged (ultimately depends on the Anord ^¬ voltage even after the available installation space, ideally, the power density at the position of the filter is not too high).

Preferably, the filter relative to a beam with the recirculated to the light source portion of Be ^¬ illuminating light is displaceable, such as rotatable and / or displaceable. Reference is also expressly made to the possibilities mentioned with regard to the storage of the recycling mirror, which are also possible with regard to the storage of the filter (the "main direction" of the recirculated illumination light passing through the filter being based on is lowered). The filter may generally be an interference filter or an absorption filter, for example a gray filter or a neutral density filter with a filter degree that changes over the filter; However, wavelength-selective filtering is also possible, for example with a dichroic filter. Thus, for example, it would be possible to selectively reduce the amount of yellow gel in order to compensate for the above-described mixture ratio problem. In a preferred embodiment, the light source has a pump radiation unit and a phosphor element, which is irradiated with the pump radiation during operation and then emits a conversion light. The conversion is a down-conversion preferred the con- version is light so longer wavelength than that Pumpstrah ^¬ development; the conversion light has at least one überwie ^¬ constricting portion in the visible spectral region, preferably it is a whole in the visible. The conversion light may, for example, also be red or green light, preferably yellow light.

The conversion of light capable of forming the illumination light by itself (Vollkonversi ^¬ on) is preferably a partial conversion, at which it forms the illumination light together with proportionately unconverted pump radiation. The pump radiation is preferably blue light. Ge ^¬ Nerell is the illuminating light preferably white light, ie, its chromaticity coordinates, for example, in a CIE standard color chart (1931) in the ECE-white field according to the United Nations ECE Regulation 48 (for example, current revision. ECE / 324 / Rev. 1 / Add.47 /Reg.No .48 / Rev.12, can lie. In the present case, a light source with the phosphor element may be particularly advantageous because the recirculated to the Lichtquel ^¬ le illumination light can be in or scattered in the phosphor element and thus in any case partially led again to the array. This provides the benefits in terms of efficiency.

Although in the preferred light source with Leucht ^¬ material element this is generally provided directly adjacent to an exit surface of the pump radiation unit seen (such as in the case of an LED with integrally formed phosphor element), the pump radiation unit and the phosphor element are preferably spaced from each other. The pump radiation then passes upstream of a radiation surface of the phosphor element a fluid volume, preferably a gas volume, particularly preferably air; with ei ^¬ ner such a remote phosphor arrangement (also referred to as laser ac- tivated remote phosphor LARP), for example. light sources can be realized high luminance. Laser Activated Remote Phosphor light sources can be operated in trans- missive and / or reflective mode. In general, such a construction, for example, with an LED, halogen or gas discharge lamp as a pump radiation source conceivable, preferably a laser source, which may be constructed from one or more individual laser sources; As a single laser source is a laser diode be ^¬ preferred, for example. Also due to the thus possible switching ^¬ times (see below in detail).

In a preferred embodiment, the emission surface of the phosphor element is assigned a feed optics, via which the supply beam from the phosphor element reaches the array. Preferably the Zuführoptik the emission of the Leuchtstof ^¬ felements, on which the illumination light is dissipated, on the micromirror array.

In a preferred embodiment, a mirror is provided on one of the radiating surface opposite side surface, so the back, and optionally also on one or more of the adjacent side surfaces of the phosphor element. In the present case, for example, this can offer particular advantages insofar as the returned illumination light, which then enters the emission surface of the phosphor element, can be reflected on the mirror and thus guided back to the array. For example, in comparison to an illumination light recycling system that is based solely on scattering processes (see above), the proportion of recy- cled illumination light can ideally be increased. In the case of a phosphor element operated in reflection, that is to say when the incident and emitting surfaces coincide, the mirror can be, for example, a metallic solid mirror. May also independently of a mirror coating of the radiating opposite side surface of the light-emitting Stoffele ^¬ ments or can be mirrored in general also that side surface (s) of the phosphor element, lying in relation to the loading / irradiation direction perpendicular directions outside. This can help to further improve efficiency. In a preferred embodiment, the phosphor element is operated in transmission, so are Einstrahl- and radiating surface opposite to each other, wherein the mirror is arranged on the Einstrahlfläche and wavelength-dependent transmissive formed. The wavelength-dependent mirror does not necessarily have the Cover entire side surface, he could, for example, be provided only in a Einstrahlbereich thereof, the remaining side surface could also be fully mirrored. Preferably, it covers the entire Einstrahlfläche. Irrespective of this in detail, the wavelength-dependent mirror is then transmissive to the pump radiation and reflective to the conversion light. A corresponding dichroic layer system may also be preferred ^¬ di rectly applied to the input surface, such as a coating.

In a preferred embodiment, the illumination device is set up to change the output power of the pump radiation unit as a function of the portion of the illumination light that is respectively returned to the phosphor element. The greater the proportion Retired ^¬ led, the more the output power can be reduced, which helps make energy-efficient BL LEVEL ^¬ processing device. Such an adjustment of the output power can in the simplest case with a threshold or more thresholds, ie in stages, or even continuously.

The already mentioned semiconductor sources, that is to say a laser diode or an LED, can also be ^{advantageous in} that on the time scale of the micromirror movements comparatively fast changes are possible, so that also comparatively small changes (change of the tilting position of fewer actuators) follow can be. Especially at relative slow amendments ^¬ conclusions, so far as it goes, for example, fundamentally different modes of operation (such. As city driving light compared to high beam), but can for example also a halogen or gas discharge lamp as pump radiation ^¬ unit to be readjusted accordingly.

As far as a "set-up" of the lighting device is generally mentioned, this means, for example, that in operation the pump radiation / illumination ^¬ light propagates accordingly and / or the micromirror array is wired or illuminated accordingly In this case, the individual components are arranged relative to one another in such a way that pump radiation and conversion or illumination light propagate correspondingly Preferably, the illumination device has a control unit which correspondingly controls the connection of the micro-mirror actuators (switched on / off) Actuates light source accordingly.

In general, a pulsed operation may be preferred for the pump radiation unit or its individual sources (in particular laser diodes and / or LED light-emitting diodes). An adjustment of the output power can then be carried out amplitude and / or pulse width modulated, the latter is preferred.

With regard to the micromirror array, an operation may be so preferred that the actuators each time with a folding ^¬ frequency, which is many times greater than the actual switching frequency, every now and again from the one tilt position (which corresponds to the actual switching state) in the other of the two maximum possible tilt positions can be folded (in order to be folded back into the actual tilted position as a rule). Termertierender operation can offer as compared to a static circuit, for example, the life of the actuators in terms of benefits.

The actuators of the micromirror array can be operated with very high folding frequencies. Corresponding folding frequencies can be, for example, at least 100 Hz, or at least 500 or 1000 Hz; possible upper limits are, for example ^¬ at 1 MHz, 100 kHz or 10 kHz. In conjunction with an intelligent control can be set for each pixel individually any Hellig ^¬ opportunities because of the gray value or dim tion by the averaged over a period of time ratio of the time during which the actuator is in an ON state at the time the actuator is in the off state. So any gray values can be set to Lichtvertei ^¬ development to modify space and time in any location-dependent and time-dependent on the micro-mirror array. Dimming allows in particular smoother transitions when changing between different light distributions, eg. As the transition from low beam to high beam and vice versa ^¬. Furthermore, a dimming allows a smoother transition between areas of different brightness, z. B. at the cut-off line of light distribution on the street.

In a preferred embodiment, the pump radiation unit has a first and a second and optionally further pump radiation sources (preferably laser diodes and / or light emitting diodes LED), which are operated in such a way that their output powers are in a different relative relationship to each other at first times than in second times (which are different from the first). For example, the output power of one pump radiation source can be kept constant and those of the other can be reduced or increased, or a reverse change in both output powers is possible. As a result, an irradiance distribution produced with the pumping ^¬ sources of radiation on the input surface of the Leuchtstof ^¬ felements in the first points of time is in any case different from the second times. Thus, for example, a location-dependent adaptation depending on the recycled at respective times lighting light can be made.

In general, for example, with precise knowledge of the conversion and scattering properties of the fluorescent element for z. B. predefined switching pattern of the array a profile for adjusting the output power of the pumping radiation unit or for adjusting the irradiation ^¬ starch distribution on the Einstrahlfläche the Leuchtstof ^¬ felements be deposited, for example, a reduced or increased radiant power of the light source used. In the preferred case the motor vehicle headlight, there can be predefined switching paradigm ^¬, for certain operating modes (eg Abbiend-, daytime running lights, city driving lights), so the matrix-like distribution of inputs and outputs known status of the actuators. In particular, in a strongly scattering phosphor element, which thus essentially eliminates a spatial resolution of the recycled illumination light, z. As well as a correlation of the dimming only on the basis of the number of disabled actuators conceivable. In a preferred embodiment, however, a sensor unit, a radiant output and / or a Wellenlängenvertei ^¬ lung and / or a color point of a part of the illumination is however provided that is adapted to measure light. The "wavelength distribution" may, for example, relate to the measurement of an actual spectrum (transmission, absorption and / or reflection), but it is also possible to measure only the distribution or the ratio at certain wavelengths / "colors" (ie, for example Blue / yellow or RGB, etc.). Detecting a wavelength distribution or the color locus may be in particular in the case of a partial conversion of interest, if, therefore, the illumination light obtained as a mixture of convergence ^¬ sion light and the unconverted proportionately pumping radiation. The pump radiation still contained in the illumination light returned to the phosphor ^element is then at least partially converted, which shifts the ratio of unconverted pump radiation to conversion light in favor of the latter after recycling. If, for example, a light source with two pump light sources of slightly different wavelengths is used, whose respective pump radiation can convert the phosphor element to different degrees, a change in the ratio of the output powers of the light sources can offer a degree of freedom for adjustment.

In the case of the blue / yellow mixture, for example, the renewed conversion increases the proportion of yellow, which may necessitate ^subsequent regulation. The sensor unit is preferably coupled to a control unit which controls the game as pump radiation unit at ^¬; it is For example, a separate light source conceivable especially for a color balance.

In a preferred embodiment, the phosphor element is mounted so displaceable relative to the pump radiation unit that the conversion properties of the phosphor element in a first offset position differ from those in a second displacement position (which is different from the first). Concerning. the "displaceable" storage is referred to the above disclosure on the possibilities of storage of the recycled mirror, the same possibilities are also for the phosphor element in question (as the "main direction" is based on the incident pump radiation). It is for example a rotatable mounting possible, it being possible to change with the rotational movement between the offset positions. But it is also a displaceable La ^¬ delay possible, the displacement direction can be oblique, preferably perpendicular, to a main direction of the pump radiation on the Einstrahlfläche. Preferably, a rectilinear displacement, for example, operated by a linear motor / -Aktor. In general, in combination with non-collimated pump radiation (ie, which impinges convergent or divergent), it would also be conceivable to displace along the main direction just mentioned, whereby the irradiated area just changes (increases / decreases).

In a preferred embodiment, the supply, the input and the Aus-beam bundle fill a total angular range, which is in principle accessible with the array, together to at least 80%, more preferably at least 90% or 95%, most preferably completely on. It will thus in particular also used the transient Fiat State of Akto ^¬ ren. This is a transitional state between the two maximum tilt positions of a respective actuator, which thus occupies the undeflected actuator or which is present when the actuator is not operated. The mirror surfaces of the actuators are then ^¬ thus at least approximately parallel to the chip plane; the Transient Fiat State is therefore z. B. in the Projekti ^¬ onsanwendungen mentioned above not used, because it may give unwanted reflections from the rest of the chip surface (connecting webs, metallization, etc.) in the associated solid angle range.

Present can be explained by the use of Übergangsbe ^¬ Empire, the angular range depending ray beam increase, possibly at the cost of somewhat reduced contrast. With an enlarged angle range, for example, more light can be guided over the array or broader distributed light (a light source of lower luminance) can be used. So ^¬fern generally referred to an "angle range" per beam or in the present case to a "total angular range", this refers to a consideration in a mirror surface of a respective actuator vertical plane in which the tilt of the actuator and the Extension of the beam is maximum. In a preferred embodiment, the micromirror actuators each have a possible deflection angle of the amount of at least 10 °, preferably at least 12 °, particularly preferably at least 15 ° (possible upper limits may be, for example, at most 30 °, 25 ° or 20 ° lie) . This deflection angle is taken in each case between the 0 ° axis and a maximum tilt position, it is preferred on both sides of the 0 ° axis the same size, it is so then, for example, +/- 10 ° or +/- 12 ° or +/- 15 °.

The invention also relates to a motor vehicle headlight and / or a motor vehicle signal light, in particular a motor vehicle headlight and / or a headlight with a lighting device disclosed herein.

The invention also relates to the use of a presently disclosed lighting device or a motor vehicle headlight with such a for lighting, in particular for adaptive street lighting and / or for the projection of (additional) information on the road or vehicle environment. Reference is expressly made to the above statements, which are likewise intended to disclose a corresponding use or the motor vehicle headlamp. In general, however, the lighting device could also be used, for example, in an effect light spotlight or generally in the entertainment area or also in the area of architainment lighting. In the category of use, the vehicle lighting Subject Author ^¬ fend, a presently disclosed Beleuchtungsvorrich ^¬ tung also independent of that contained in the off-ray beam part of the illumination light is returned to the light source be of interest. Contained in the off-ray beam lighting ^¬ light can then be used proportionately otherwise, that is for another light function than that contained in the one-ray beam light at least; The latter can be used, for example, to illuminate the street (front headlamp), the former then, for example, for signal lights or in the interior. be used. This otherwise used light can be performed, for example, via a light guide to the respective light other function.

Brief description of the drawings

In the following, the invention will be explained in more detail with reference to exemplary embodiments, wherein the individual features in the context of the independent claims in another combination may be essential to the invention and also continues to not be distinguished in detail between the claim categories. In detail shows

Figure 1 using the example of a projection application a not used in the invention micromirror array in which temporarily unnecessary light is destroyed in ei ^¬ nem absorber; 2 shows a lighting device according to the invention, is recycled in the temporarily unused lighting ^¬ light.

Preferred embodiment of the invention

FIG. 1 illustrates, by way of example, a projection application, a micromirror array which is not operated according to the invention, of which a micromirror actuator 1 is shown. The micro mirror array is such zugeord net ^¬ a light source 2 that a feed beam 3 coincides with a light emitted from the light source 2 illuminating light on the Mik ^¬ rospiegel array. In the present case, only one micromirror actuator 1 of the array is shown for purposes of illustration (to which only one partial beam falls ei ^¬ nually), yet the supplied / reflected light is illustrated by the "beam", ie based on the array all in one .

The micromirror actuator 1 is shown in the undeflected state. He is between two maximum tilt positions, which are indicated by dashed lines, tilted back and forth. The undeflected state is referred to as Transient Fiat State, and in this case one maximum tilt position corresponds to the one and the other to the tilt position. In the off-tilted position of the digital micromirror device 1 reflects the fall- en to its mirror surface 4 illumination light onto an absorber 5, Ligh ting light ^¬ is therefore not used. On the other hand, in the on-tilt position, the illumination light is guided through an illumination optics 6 (a lens system), ie used for imaging in the case of the projection application. FIG. 1 further illustrates how a total angular range of 96 °, which is accessible overall by the tiltability of the micromirror actuators 1 by +/- 12 ° in the present case, can be divided. In this total angular range, the one-beam 8 (for illumination optics 6), the out-beam 9 (in the absorber 5) and the transient beam 10 are shown in addition to the feed beam 3. The one-beam 8 and the out-beam 9 are spaced apart by the transient beam 10 to keep as far as possible unintentional reflections from the on-beam 8 for good contrast. These can be Fiat State occur increasingly because the Spiegelflä ^¬ chen the actuators are parallel to the chip level and so also reflections from the rest of the chip surface (connecting webs, metallization, etc.) can be NEN registered.

FIG. 2 shows a lighting device according to the invention which initially differs from that according to FIG. 1 in that the out-beam 9 is not guided into an absorber 5. Instead, a recycling-mirror 15 is provided, at its reflection surface 16, the illumination light included in respective time points in the off-ray beam 9 is re ^¬ flexed back to the micromirror array and transfer it back to the light source. 2 Recycling between the mirror 15 and the micromirror array a recycling optical system is arranged optional 17 (here shown schematically as a single bus ^¬ lens), which maps the reflection surface 16 to the array.

The recycling mirror 15 may be planar when using a recycling optics, but also have a spherical or freeform reflection surface 16 depending on the optical design. A portion of the light returned via respective actuators in the "on state" could also impinge outside of the feed beam 3 and thus adjacent to the light source 2, which could affect the quality of the image, which could then be reduced by an optional absorber (e.g. B. Riffle sheet) at this point prevent.

Instead of destroying the respectively unneeded illumination light in an absorber, it is used in the inventive according to the lighting device at least partially led back to the light source 2. As will become clear below with reference to the description of the light source 2 in detail, it can then be guided from there at least partially again in the direction of the micromirror array and thus be used in the Er ^¬ result for lighting purposes. So it increases the efficiency, which may be of particular interest in the automotive sector. The light source 2 will now be explained in more detail in detail and then the mode of operation of the array in the field of application "motor vehicle headlights".

The light source 2 of the illumination device according to the invention has a pump radiation unit 20, vorlie ^¬ ing an array of a plurality of laser diodes (not shown in detail nen). The pump radiation 21 emitted therefrom, in the present case blue laser light, strikes a phosphor element 22, which in the present case has yttrium aluminum garnet (YAG: Ce) as the phosphor. This emits at the excitation with the pumping radiation 21 toward a onslicht Konversi- which forms together with proportionately not Conver ^¬-oriented pump radiation 21, an illumination light 23rd

The illuminating light 23 is discharged at one of the Einstrahlflä ^¬ surface 24 of the fluorescent member 22 opposite from ^¬ radiating surface 25 and passes via a Zuführop- tik 26 to the micromirror array. 15 lighting ^¬ light across the array back to the light source 2 reflectors ^¬ advantage in respective times of the recycling levels, it is true by the Zuführoptik 26 on the light ^¬ material element 22. From there, it will then proportionally already due to scattering processes and absorption -

Emission processes again in the direction of the micromirror Arrays guided (recycled). Further, a mirror 27, NaEM ^¬ Lich a dichroic coating disposed on the single beam ^¬ surface 24 of the fluorescent member 22 which is transmissive for the pump radiation 21, however, the Konversi- onslicht reflected. This will further increase the proportion of total recycled light.

The illumination optical unit 6 images the micromirror array into the infinite, that is to say that from each actuator 1, the illumination optical system 6 downstream of a respective sub-beam is guided in a collimated manner into a respective spatial direction. The illumination optics 6 converts the matrix-shaped arrangement of the actuators 1 (spatial distribution) into a solid angle distribution, ie illumination light can be selectively supplied to respective spatial directions (on-tilt position of the respective actuator 1) or not (off-tilt position of the respective actuator 1). A preferred field of application is the adaptive street lighting with a motor vehicle headlight, cf. also the description introduction in detail. Optionally, a filter 28 can be arranged in the out-beam bundle 9 between the recycling optics 17 and the recycling mirror 15, with which the spectral properties of the portion of the light source 2 fed back to the light source 2 and, ultimately, that of the illumination application Adjust the illumination light. For this purpose, the filter 28 may, for example, also have a different wavelength depending on the filter degree and / or be displaceable, cf. the introduction to the description.

In the case of the illumination device illustrated in FIG. 2, the total angular range of the arrangement according to FIG. 1 is shown according to the four beams 3, 8-10 divided under ^¬ . Since the demands on the contrast in the mentioned automotive applications are generally not so high, however, the Transient Fiat State can also be used for the actual illumination. Thus, the input beam 8 and the out beam 9 can also be provided directly adjacent one another, ie the total angular range is then divided into only three beam bundles, each of which can have a correspondingly slightly larger aperture angle. In simple terms, therefore, more light or light collected from a larger angular range can then be passed over the array.

LIST OF REFERENCE NUMBERS

Mikrospiegelaktor 1 light source 2 supply beam 3 mirror surface 4 absorber. 5

Illumination optics 6

Beam 8

Out-beam 9 Transient beam 1 0

Recycling mirror 15

Reflection surface 1 6

Recycling optics 17

Pump radiation unit 2 0 pump radiation 2 1

Phosphor element 22

Illumination light 23

Irradiation surface 24

Radiating surface 25 Feeding optics 2 6 Mirror (dichroic) 27

Filter 28

Claims

EXPECTATIONS

Lighting device with

a light source (2) for emitting an illuminating light (23),

a micromirror array with a large number of micromirror actuators (1) arranged in a matrix and illumination optics (6),

wherein the light source (2) and the micromirror array are arranged relative to one another in such a way that, during operation, a feed beam (3) with the illuminating light (23) is directed from the light source (2) to the ^micromirror actuators (1) of the micromirror array guided and reflected on these, with the ^reflection in the time integral

- a single beam

(8) is reflected by the ^microspy actuators (1) in a respective on-tilt position via the lighting optics (6) for a lighting application and

- an off-beam beam (9) is reflected by the ^microspy actuators (1) in a respective off-tilt position next to the illumination optics (6),

characterized in that a portion of the illumination ^light contained in the off beam is at least partially guided back to the light source (2).

Lighting device according to claim 1 with a recycling mirror (15), onto which at least part of the off-beam (9) falls in such a way that the part of the illumination light contained in the off-beam (9) is at least partially ^reflected back to the light source (2) on the recycling mirror (15).

Illumination device according to claim 2, in which the micromirror array and the recycling mirror (15) are arranged relative to one another in such a way that the part of the illumination light reflected on the recycling mirror (15) back to the light source (2) is reflected by the recycling mirror (15) is reflected onto the micromirror array and from there to the light source (2).

Lighting device according to claim 3 with recycling optics (17), which is preferably arranged between the recycling mirror (15) and the micromirror array in such a way that it places a reflection surface (16) of the recycling mirror (15) on the ^microspy gel array.

Lighting device according to one of claims 2 to 4, in which a reflection behavior of the recycling mirror (15) can be adjusted.

Lighting device according to claim 5, in which a reflection surface (16) of the recycling mirror (15) can be folded at least in certain areas and the reflection behavior of the recycling mirror (15) can be adjusted by folding. Illumination device according to claim 5 or 6, in which the recycling mirror (15) is so relative to the off-beam

(9) is mounted so that the reflection behavior of the recycling mirror (15) can be adjusted by moving the recycling mirror (15).

Illumination device according to one of the preceding claims with a filter (28) which is mounted in such a ^way that it can be offset so that the spectral properties of the part of the illumination light reflected for the illumination application can be adjusted when the filter is offset.

Lighting device according to one of the preceding claims, in which the light source (2) has a pump radiation unit (20) for emitting pump ^radiation (21) and a phosphor element (22) for at least partially converting the pump radiation (21) into a conversion light, which con ^¬ version light at least partially forms the lighting ^¬ light (23).

10. Lighting device according to claim 9, which is ^designed for a change in an output power of the pump radiation unit (20) depending on a portion of the illumination light (23) returned to the light source (2) at ^certain times.

11. Lighting device according to claim 9 or 10, in which the pump radiation unit (20) has a first and has a second pump radiation source and is set up for operation of the pump radiation sources in such a way that their output powers are in a different relative relationship to one another at first times than at second times, which means that in the first times an irradiation ^intensity distribution on an irradiation surface (24) of the phosphor element ( 22) is different than in the second points in time.

Illumination device according to one of the preceding claims with a sensor unit which is ^designed to measure at least one of an optical power, a wavelength distribution and a color locus of a part of the illuminating light (23).

Lighting device according to one of the preceding claims, in which a respective tiltability of the micromirror actuators (1) between the on and off tilting positions determines a maximum accessible total angular range (30) of the micromirror array, which total angular range (30) the supply beam of rays (3), the in-beam of rays (8) and the out-beam of rays (9) together fill at ^least 80%.

Motor vehicle headlight with a lighting device according to one of the preceding claims.

Use of a lighting device according to one of claims 1 to 14 or a motor vehicle headlight for lighting, especially for adaptive street lighting.