ILLUMINATION DEVICE FOR EMISSING ILLUMINATION LIGHT

Abstract

Lighting device (1) for emitting illuminating light (6), with a pump radiation source (2) for emitting a pump radiation (3), a phosphor element (4) for converting the pump radiation (3) into a conversion light, which at least partially forms the illumination light (6), and a transmissive plate (20), wherein the pump radiation source (2), the phosphor element (4), and the transmissive plate (20) are arranged relative to one another in such a way that, during operation, the pump radiation (3) falls onto an incident radiation surface (5) of the phosphor element (4), and the illuminating light (6) subsequently emitted at an emitting surface (7) of the phosphor element (4) with a radiation center of gravity direction (27) passes through the transmissive plate (20) via two passage surfaces (23, 24), namely a light entry surface (23) and an opposite light exit surface (24), wherein the passage surfaces (23, 24) of the transmissive plate (20) are tilted relative to one another in such a way that the illuminating light (6) has a propagation center of gravity direction (28) tilted relative to the radiation center of gravity direction (27) immediately downstream of the transmissive plate (20); and wherein the transmissive plate (20) is a wedge plate and the passage surfaces (21-24) of the transmissive plate (20) are each planar.

Description

Technical area

[0001] The present invention relates to a lighting device for emitting illumination light, which has a phosphor element. State of the art

[0002] In lighting devices of the type relevant here, a phosphor element is irradiated with pump radiation. The phosphor element converts the pump radiation into conversion light, which then at least partially forms the illumination light emitted by the lighting device. In the case of so-called partial conversion, the conversion light can form the illumination light together with an unconverted portion of pump radiation, in which case, for example, blue pump light may be preferred as the pump radiation. On the other hand, however, the conversion light alone can also form the illumination light (full conversion). Regardless of the specific implementation, light sources of high luminance can be realized with the combination of a pump radiation source and a phosphor element arranged at a distance from it.

[0003] For example, lighting devices for a vehicle are known from US 5 390 084 A, DE 199 08 480 A1, DE 20 2015 001 682 U1. Description of the invention

[0004] The present invention is based on the technical problem of providing a particularly advantageous lighting device.

[0005] According to the invention, this object is achieved by an illumination device for emitting illumination light, comprising a pump radiation source for emitting pump radiation, a phosphor element for converting the pump radiation into a conversion light, which at least partially forms the illumination light, and a transmissive plate, wherein the pump radiation source, the phosphor element and the transmissive plate are arranged relative to one another in such a way that, during operation, the pump radiation falls on an incident surface of the phosphor element and the illumination light then emitted at an emission surface of the phosphor element with a radiation center direction passes through the transmissive plate via two passage surfaces, namely a light entry surface and an opposite light exit surface, wherein the passage surfaces of the transmissive plate are tilted relative to one another in such a way thatthat the illuminating light of the transmissive plate has a propagation center of gravity direction immediately downstream of the beam center of gravity, and a A lighting device constructed from the same components, in which the transmissive plate, however, is penetrated by the pump radiation before it strikes the incident surface of the phosphor element, and in the process the direction of gravity of the pump radiation is tilted such that the pump radiation strikes the incident surface with an incident direction of gravity that is tilted relative to an impact direction of gravity with which the pump radiation strikes the radiation entry surface of the transmissive plate.

[0006] Preferred embodiments can be found in the dependent claims and the entire disclosure, whereby the description does not always distinguish in detail between device and method or use aspects; in any case, the disclosure is to be read implicitly with regard to all claim categories.

[0007] The inventor has determined that, for example, there may be small deviations in the relative arrangement of the pump radiation source and the phosphor element from one lighting device to another, e.g., due to mechanical tolerances of the components used (e.g., mountings, etc.) or due to assembly, i.e., due to manufacturing variations. As a result, an illuminating light spot on the radiating surface of the phosphor element, whose position depends on that of the pump radiation spot on the incident surface, can be offset from a reference point. The radiating surface is typically associated with an illumination optics system, with the relative arrangement of the phosphor element and the illumination optics being predetermined (which ultimately also determines the reference point).

[0008] Due to the offset of the illumination light spot on the radiating surface, the transmission through the illumination optics can be reduced, thus reducing their efficiency. However, a disadvantage can also arise, for example, if the illumination optics are preferably configured to direct the illumination light emitted at different locations on the radiating surface in different spatial directions, which can result in angular deviations in the beam guidance and thus an impairment in the far field.

[0009] According to the invention, a transmissive plate with mutually tilted passage surfaces is arranged in the beam path with the pump radiation or in the beam path with the illumination light. In the former case, a slight tilt of the pump radiation shifts the position of the pump radiation spot on the incident radiation surface such that the illumination light spot is closer to the reference point; in the latter case, the illumination light spot is not actually shifted on the emission surface, but rather a kind of virtual offset results due to the tilted beam guidance (seen from the illumination optics, the illumination light spot moves closer to the reference point). In both cases, the offset is compensated, and the illumination light can be guided essentially along the desired path through the illumination optics, for example, despite mechanical tolerances / variations during assembly.

[0010] A respective "centroid direction" is determined at the respective point under consideration as the average of all directional vectors of the beam with the respective radiation / light under consideration. During this averaging process, each directional vector is weighted by its associated radiant intensity. The illuminating light is emitted at the emitting surface essentially in a Lambertian pattern, and the centroid direction of the emission is then perpendicular to the emitting surface.

[0011] The tilt of the pump radiation / illumination light introduced by the transmissive plate is preferably rather small, i.e., for example, not greater than, in the order of naming, preferably at most 20°, 18°, 16°, 14°, 12°, or 10°; possible lower limits can be, for example, at least 1°, preferably at least 2°, and more preferably at least 3°, whereby, in general, the lower and upper limits can also be of interest independently of one another and should be disclosed.

[0012] The illumination light preferably has a predominant part of its spectral intensity distribution in the visible spectral range (380 nm to 780 nm), particularly preferably it lies entirely in the visible spectrum. The conversion is preferably a downconversion, meaning the conversion light has a longer wavelength than the pump radiation. The pump radiation can generally also be UV radiation, for example, but blue pump light is preferred; the illumination light is preferably white light, which can result, for example, from a mixture of blue pump light and yellow conversion light. Express reference is also made to the introductory remarks.

[0013] The pump radiation is preferably laser radiation; the pump radiation source is preferably a laser, which can be constructed from one or more individual laser sources, e.g., in the form of an array. A semiconductor laser is preferred as the laser source; a single laser source is therefore preferably a laser diode with, for example, an emission wavelength in the range of approximately 405 nm to approximately 470 nm. In general, in the case of multiple individual laser sources, these can differ, for example, in their dominant wavelength; preferably, they have the same dominant wavelength; particularly preferably, they are structurally identical. The pump radiation source can be configured for alternating or at least temporally not completely overlapping (simultaneous) operation of the individual laser sources, or preferably for simultaneous operation.

[0014] The "transmissive" plate is in any case transmissive for the respective radiation / light in question, for example with a transmittance averaged across the spectrum of the radiation / light of at least 85%, 90%, 95% or 98% (increasingly preferred in descending order); although complete transmission is preferred, technically determined upper limits may be, for example, 99.99%, 99.9% or 99%. Preferably, the plate material from which the transmissive plate is provided, e.g., glass or a plastic material (e.g., polycarbonate), has a constant refractive index across the transmissive plate. In general, however, a refractive index that varies at least in certain regions across the plate would also be conceivable; thus, the plate could be designed like a gradient lens, with the refractive index gradient supporting the tilting.

[0015] The transmissive plate can, for example, be "plate-shaped" in that it can have a mean thickness extension averaged over the plate in a direction perpendicular to the light entry surface / radiation entry surface, which is smaller than the mean extension (average of the smallest and largest extension) of the side surface containing the light entry surface / radiation entry surface, for example at most 1 / 3, 1 / 4 or 1 / 5 thereof, whereby possible lower limits can be, for example, 1 / 1,000 or 1 / 100 (each with increasing preference in the order of mention) and upper and lower limits are generally of interest independently of one another.

[0016] In a preferred embodiment, the illumination device has an illumination optics system, which can generally also be provided for non-imaging purposes (for example, as a so-called compound parabolic concentrator, CPC), but is preferably imaging. The illumination optics are arranged relative to the radiating surface in such a way that illumination light emitted at different points on the radiating surface is guided in different spatial directions. One embodiment can preferably be such that a respective illumination light beam emanating from a respective point on the radiating surface and passing through the illumination optics is individually collimated downstream of the latter. In principle, the illumination optics can also be constructed from a single lens; preferably, it is constructed from several individual lenses arranged one after the other with respect to the propagation of the illumination light.Alternatively or in addition to a lens, the illumination optics can also have a reflection surface or reflection surfaces for beam guidance, i.e. (also) be designed as a reflector.

[0017] In a preferred embodiment, the passage surfaces of the transmissive plate are each individually flat. Generally, "passage surface" refers to the area of ​​a generally larger side surface of the transmissive plate through which the pump radiation / illumination light passes, whereby only the pump radiation / illumination light on the respective path is taken into account, thus, for example, backscattering effects are disregarded. The pump radiation enters the transmissive plate through the radiation entrance surface and exits through its radiation exit surface; the illumination light enters the transmissive plate through the light entrance surface and exits through the light exit surface; each of these surfaces is also referred to as a "passage surface."

[0018] In a preferred embodiment, the transmissive plate is a wedge plate, i.e. its two side surfaces, each containing one of the passage surfaces, are each planar in themselves and are tilted towards each other.

[0019] In a preferred embodiment, the two passage surfaces of the transmissive plate are tilted relative to each other by a tilt angle of at most 20°, with increasing preference in the order of naming at most 18°, 16°, 14°, 12°, or 10°. Preferred lower limits can, for example, be at least 1°, 2°, or 3° (increasing preference in the order of naming) and are generally of interest regardless of an upper limit. The tilt angle corresponds to the intersection angle of two planes, each of which contains one of the passage surfaces. In the preferred case of the wedge plate, it corresponds to its wedge angle.

[0020] In a preferred embodiment, the phosphor element and the transmissive plate are arranged relative to one another such that one of the passage surfaces of the transmissive plate is parallel to the incident irradiation surface and / or the emitting surface of the phosphor element. "Incident surface" and "emitting surface" each refer to the entire respective side surface of the phosphor element; generally, the incident irradiation surface and / or the emitting surface are each preferably planar, particularly preferably both are planar and parallel.

[0021] The phosphor element can, for example, have the shape of a flat cuboid whose extension in one thickness direction is considerably smaller than in each of the perpendicular surface directions (e.g., at most 1 / 5 or 1 / 10 of that, with possible lower limits of 1 / 1000 or 1 / 100, respectively). The incident and emitting surfaces then each extend in the surface directions, thus, for example, when operated in transmission mode (see below), they are opposite each other with respect to the thickness direction. In the thickness direction, a phosphor element operated in partial conversion can, for example, have a thickness of at least 10 µm, preferably at least 30 µm, particularly preferably at least 60 µm, whereby possible upper limits can, for example, be at most 200 µm, 150 µm or 100 µm (increasingly preferred in the order of mention) and in general the upper and lower limits are also of interest independently of one another.In contrast, a phosphor element operated in full conversion can be thicker, for example have a thickness (taken in the thickness direction) of at least 0.5 mm, 0.8 mm or 1 mm, whereby possible upper limits can be, for example, at most 3 mm, 2.5 mm or 2 mm (each increasingly preferred in the order in which they are mentioned) and upper and lower limits are generally also of interest independently of each other.

[0022] In a preferred embodiment, the transmissive plate is mounted so as to be movable relative to the phosphor element, for example, displaceable in a direction parallel to its incident and / or emitting surface (a surface direction). Such displaceability can occur precisely along one axis or along two axes, which are then preferably perpendicular to each other (and each parallel to the incident and / or emitting surface).

[0023] With such a design, adjustments can be made, for example, during operation or over the lifetime of the component. This can be of interest in the case of a displacement dependent on the operating temperature (different thermal expansion coefficients) or a displacement that builds up over a long period of time due to vibrations / shocks, for example. Regarding a further area of ​​application, please refer to the following discussion on automotive headlights.

[0024] In a preferred embodiment, the phosphor element and the transmissive plate are provided in direct optical contact. "In direct optical contact" means that the pump radiation / illumination light should not penetrate any optically effective air volume between them; therefore, for example, an intermediate material with a refractive index ≥ 1.2, preferably ≥ 1.3, should be provided between the transmissive plate and the phosphor element; preferably, the two are directly adjacent to one another (in the context of this disclosure, refractive index specifications generally refer to the refractive index at λ = 589 nm). The intermediate material can, for example, form a joining layer, i.e., create an adhesive bond between the transmissive plate and the phosphor element.

[0025] In general, the transmissive plate and the phosphor element can be provided in direct optical contact with each other even if the transmissive plate is movably mounted, as described above. In this case, an immersion liquid, for example, can establish direct optical contact. However, this is preferably achieved in the case of a static arrangement, i.e., when the phosphor element and the transmissive plate are fixed in their relative position to each other, which can also be preferred in general (even regardless of direct optical contact).

[0026] In a preferred embodiment, a transmissive plate is provided which is arranged at a distance from the phosphor element via a gas volume, preferably air. In the case of the upstream arrangement, the pump radiation should therefore pass through the gas volume between the transmissive plate and the phosphor element; in the downstream arrangement, the illuminating light passes through the gas volume between the phosphor element and the transmissive plate. The distance between the phosphor element and the transmissive plate can be, for example, at least 0.5 mm, preferably at least 1 mm, particularly preferably at least 1.5 mm; possible upper limits can be, for example, at most 20 mm, 15 mm, 12 mm or 10 mm (increasingly preferred in the order mentioned), whereby the upper and lower limits can generally also be of interest independently of one another.For a definition of "distance," reference is made to the following explanations in the context of a distance between the phosphor element and the transmissive plate, which is predefined during production. For example, in the case of an arrangement in illuminating light, the transmissive plate can then also form the end window of a housing that encloses the phosphor element, thus concealing the housing, for example, together with another housing part, at least to one half of the space (not optically).

[0027] In general, operation in reflection is also possible for the phosphor element, meaning the incident and emitting surfaces can coincide. The transmissive plate could then be used to tilt both the pump radiation and the illumination light. However, operation in transmission is preferred, meaning the incident and emitting surfaces are opposite each other. Generally, two transmissive plates could be provided, one in the beam path of the pump radiation and the other in that of the illumination light; however, exactly one transmissive plate is preferred.

[0028] The invention also relates to a set comprising several illumination devices that are indistinguishable from one another except for their respective transmissive plates. However, the transmissive plates of the set each have passage surfaces tilted to different degrees relative to one another, i.e., a different tilt angle (or wedge angle in the case of the preferred wedge plates). Thus, the pump radiation / illumination light is tilted to different degrees from one illumination device to the next, thus compensating for, for example, a different offset (see also the explanations at the beginning).

[0029] The invention also relates to a method for manufacturing a lighting device disclosed herein. For this purpose, the pump radiation source and the phosphor element are, for example, brought into the relative position they will then also have in the finished product; preferably, the two are fixed in this relative arrangement, specifically with the mounting means that then also hold them in the relative position in the finished product. The pump radiation source is then activated, so that pump radiation falls onto the incident radiation surface in the form of a pump radiation spot, and illumination light is emitted from an illumination light spot at the emission surface.In the context of this disclosure, "spot" generally refers to the respective area of ​​the incident or emitting surface that is irradiated with the pump radiation or from which the illumination light is emitted; the edge of a spot is, by definition, located where the irradiance has dropped by half, thus the spot is determined by the half-width (alternatively, a reference to a drop to 1 / e could be used, for example). 2 possible).

[0030] During production, the offset of the illumination light spot is then determined. This offset can, for example, be taken between the centroid of the illumination light spot, which is formed purely geometrically without weighting the irradiance, and the reference point. The reference point is preferably determined as the intersection point of the radiating surface with the optical axis of an illumination optics system assigned to the radiating surface. However, at the time the offset is determined, the illumination optics do not necessarily have to be mounted; their mounting position is known, and thus also the position of the reference point.

[0031] For example, a camera can be temporarily positioned during production at the location where the illumination optics will later be mounted to capture the illumination light spot. Since the camera's position relative to the subsequently mounted illumination optics is known, the offset can be determined from the image.

[0032] Depending on the offset, a suitable transmissive plate is then selected, the tilt angle of which increases with the offset. Thus, for the respective lighting device being manufactured, a transmissive plate suitable for compensating the offset is selected from several transmissive plates with different tilt angles. The transmissive plates, which are kept in stock for possible use depending on the determined offset, can cover a tilt angle interval, for example, with equidistant support points, approximately in 1° increments.

[0033] Preferably, an offset interval is assigned to the tilt angle interval such that each available tilt angle is assigned a subinterval of the offset interval. The subintervals are disjoint to one another and together completely fill the offset interval. The determined offset is then assigned to one of the subintervals, which determines the tilt angle suitable for compensation and thus which transmissive plate to use.

[0034] Regardless of the details, depending on the type of construction, the transmissive plate is installed either assigned to the incident radiation surface in such a way that it lies in the beam path with the pump radiation, or assigned to the emitting surface in the beam path with the illumination light (these alternatives concern the preferred operation in transmission).

[0035] In a preferred embodiment, a predefined distance from the phosphor element is specified for the transmissive plate, regardless of the offset. This means that the tilt angle can vary from lighting device to lighting device, but the distance is always the same. The distance is taken as the shortest connecting line between the phosphor element and the transmissive plate. In the preferred case of the flat incident and emitting surfaces, it is taken along a straight line perpendicular thereto. When arranged in the illumination light, the preferably flat light entry surface of the transmissive plate is preferably arranged parallel to the emitting surface; when arranged in the beam path of the pump radiation, the preferably flat radiation exit surface of the transmissive plate is preferably arranged parallel to the incident surface.

[0036] Although compensation of the offset via the tilt angle is preferred and compensation via the tilt angle alone is particularly preferred, a different offset could generally also be compensated by a distance adjustment, and more generally even exclusively by a distance adjustment.

[0037] In a preferred embodiment, the transmissive plate is installed oriented such that an angle taken between the passage surfaces of the transmissive plate in a sectional plane containing a straight line connecting the reference point to the illuminating light spot is equal to the tilt angle. Said sectional plane is perpendicular to the incident and / or emitting surface; the connecting line is preferably defined by the centroid of the illuminating light spot and the reference point. Figuratively speaking, the transmissive plate is thus arranged such that a direction predetermined by the wedge shape points along the connecting line from the illuminating light spot to the reference point.

[0038] The invention also relates to the use of a presently disclosed lighting device for lighting, in particular for motor vehicle (vehicle) lighting, for example in an automobile. An advantageous field of application can be in the field of motor vehicle headlights, in which case adaptive lighting may also be possible. "Adaptive" can, for example, mean automated lighting depending on the preceding / oncoming traffic, so that, for example, certain areas are specifically excluded from a maximum accessible illumination cone. However, the "adaptive" lighting can also, for example, be implemented depending on the steering position of the vehicle itself, thus referring to adaptive (steering) cornering lights.This can be an interesting field of application, particularly in the case of the transmissive plate described above, which is mounted so as to be movable relative to the phosphor element, so that the steering, i.e. the tilting of the illumination light cone, can be realized, for example, by moving the transmissive plate. Short description of the drawings

[0039] In the following, the invention is explained in more detail using exemplary embodiments, whereby the individual features within the scope of the independent claims can also be essential to the invention in other combinations and furthermore, a distinction is not always made in detail between the different claim categories.

[0040] In detail, Fig. 1 a lighting device with pump radiation source, phosphor element and lighting optics in a schematic representation to illustrate an occurring offset; Fig. 2 two inventive possibilities for compensating a Fig. 1 illustrated offset, each with a transmissive plate; Fig. 3a-c different transmissive plates for compensating an offset, which differ in their respective tilt angle; Fig. 4 as an intermediate step in the manufacture of a lighting device according to the invention, the determination of a Fig. 1 illustrated offset. Preferred embodiment of the invention

[0041] Fig. 1 shows a lighting device 1 with a pump radiation source 2, namely a laser diode that emits pump radiation 3 in the form of blue laser light. The pump radiation 3 impinges on a phosphor element 4 (in this case made of cerium-doped yttrium aluminum garnet, Ce:YAG), specifically on an incident surface 5 of the phosphor element 4. Upon excitation with the pump radiation 3, the phosphor element 4 emits a conversion light, which, together with an unconverted portion of the pump radiation 3, forms an illumination light 6.

[0042] In this setup, the illumination light 6 is emitted in transmission from a radiation surface 7 opposite the incident radiation surface 5. In reality, the emission occurs in a Lambertian pattern (although there may be certain differences in the radiation characteristics of the conversion light and the unconverted pump radiation); for simplicity, only one beam is shown, which represents the main propagation direction of the illumination light 6, composed of unconverted pump radiation and conversion light, in the output direction. The emission of the conversion light is in reality omnidirectional, meaning that conversion light would also be emitted at the incident radiation surface 5.In order to make this usable as illumination light 6, a wavelength-dependent reflective (dichroic) coating is provided there, which is not shown for the sake of clarity (the coating is transmissive for the pump radiation 3, but reflective for the yellow conversion light here).

[0043] The radiating surface 7 is assigned an illumination optic 8, with which illumination light 6 emitted at different points on the radiating surface 7 is guided in different spatial directions (not shown in detail). The illumination optic 8 has an optical axis 9, the intersection point of which with the radiating surface 7 defines a reference point 10. Although an illumination light spot (see also Fig. 4 for illustration) is not point-shaped, but has a certain extent and can exhibit a certain ellipticity, the center of gravity of the illumination light spot should lie in the reference point 10 so that the light can be guided through the illumination optics 8 with maximum efficiency.

[0044] Due to mechanical tolerances, for example, the pump radiation source 2 and the phosphor element 4 are now slightly offset from one another, whereby the relative position of the phosphor element 4 and the illumination optics 8 is predefined, i.e., the reference point 10 is fixed. Since the phosphor element 4 and the pump radiation source 2 are offset from one another, there is also an offset 11 between the illumination light spot (specifically, its centroid) and the reference point 10. The illumination optics 8 is depicted here in an extremely simplified manner; in reality, it may be a complex lens system whose efficiency is impaired by the offset 11.

[0045] Fig. Figure 2 shows the inventive compensation of the offset 11 with a transmissive plate 20, wherein two arrangements are shown combined in the figure, thus ultimately two illumination devices are combined. The transmissive plate 20 can be arranged either upstream of the incident surface 5 in the beam path of the pump radiation 3 or downstream of the emitting surface 7 in the beam path of the illuminating light 6. In the first case, the pump radiation 3 strikes a radiation entry surface 21 of the transmissive plate 20 and exits at the opposite radiation exit surface 22 towards the phosphor element 4. In the second case, the illuminating light 6 strikes a light entry surface 23 of the transmissive plate 20 and exits at the opposite light exit surface 24 to the (in Fig. 2 not shown) illumination optics 8.

[0046] In the arrangement upstream of the incident radiation surface 5 of the phosphor element 4, an impact center direction 25 and an incident radiation center direction 26, with which the pump radiation 3 then impinges on the incident radiation surface 5, are tilted relative to each other due to the mutually tilted passage surfaces 21, 22 of the transmissive plate 20. Accordingly, the pump radiation 3 impinges on the incident radiation surface 5 in an offset manner, and the offset 11 is already compensated on the incident radiation side.

[0047] The offset 11 is virtually compensated for by the transmissive plate 20 positioned downstream of the radiating surface 7 of the phosphor element. Compared to a radiation center direction 27, a propagation center direction 28 of the illuminating light 6 is tilted downstream of the transmissive plate 20 due to the tilted passage surfaces 23, 24. Viewed from the illumination optics (not shown), the illuminating light spot on the radiating surface 7 thus appears offset, namely shifted toward the reference point 10.

[0048] The Fig. 3a-c illustrate, using the arrangement downstream of the phosphor element 4, the influence of the tilt angle of the transmissive plate 20, which in the case of the wedge plate is equal to its wedge angle, on the compensation possible with it. Fig. 3a to Fig. 3c the wedge angle / tilt angle increases and thus an increasing offset, namely starting with a small offset 11a in Fig. 3a to a large offset 11c in Fig. 3c. The distance 30 between the radiating surface 7 and the transmissive plate 20 is kept constant, which is also preferred in actual production, so that the tilt angle / wedge angle is the only control variable. Analogous to the Fig. 3a-c, in an arrangement in front of the incident radiation surface 5, an increasingly large offset would also be compensated with increasing tilt angle / wedge angle.

[0049] Fig. Figure 4 illustrates how the offset 11 is determined for a point in time during production. The radiating surface 7 is shown viewed opposite to the direction of the radiating center of gravity. The offset 11 exists between the illuminating light spot 40, specifically a surface centroid 41 thereof, and the reference point 10. The offset 40 is recorded and assigned to one of the ring-shaped, nested offset intervals indicated by dashed lines. Each offset interval is assigned a specific tilt angle / wedge angle (see Figure 4). Fig. 3a-c for comparison), the larger the offset 11, the larger the tilt angle / wedge angle.

[0050] The reference point 10, together with the centroid 41 of the illuminating light spot 40, defines a straight line 42. The transmissive plate 20, selected depending on the offset 11, is then positioned relative to the radiating surface 7 such that, in a sectional plane containing this straight line 42 (and perpendicular to the radiating surface 7 / the plane of the drawing), the angle formed between the passage surfaces 23, 24 is equal to the wedge angle. The wedge direction thus points along the straight line 42. LIST OF REFERENCE SYMBOLS 1 lighting device 2 Pump radiation source 3 Pump radiation 4 fluorescent element 5 Irradiation area 6 Illumination light 7 Radiating surface 8 Lighting optics 9 Optical axis of the illumination optics 10 Reference point 11 Offset 20, 20a, b, c Transmissive plate 21 Radiation entry surface 22 Radiation exit surface 23 Light entry surface 24 light exit surface 21, 22, 23, 24 passage areas 25 Impact center of gravity direction 26 Single beam center of gravity direction 27 Radiation center of gravity direction 28 Propagation center of gravity 30 distance 40 lighting spot 41 Center of gravity of the illumination light spot 42 straight

Claims

[1] Lighting device (1) for emitting illuminating light (6), with a pump radiation source (2) for emitting a pump radiation (3), a phosphor element (4) for converting the pump radiation (3) into a conversion light, which at least partially forms the illumination light (6), and a transmissive plate (20), wherein the pump radiation source (2), the phosphor element (4), and the transmissive plate (20) are arranged relative to one another such that, during operation, the pump radiation (3) falls onto an incident surface (5) of the phosphor element (4), and the illuminating light (6) subsequently emitted at an emitting surface (7) of the phosphor element (4) with a radiation center of gravity direction (27) passes through the transmissive plate (20) via two passage surfaces (23, 24), namely a light entry surface (23) and an opposite light exit surface (24), wherein the passage surfaces (23, 24) of the transmissive plate (20) are tilted relative to one another such that the illuminating light (6) of the transmissive plate (20) has a propagation center of gravity direction (28) immediately downstream of the transmissive plate (20) that is tilted relative to the radiation center of gravity direction (27); and wherein the transmissive plate (20) is a wedge plate and the passage surfaces (21-24) of the transmissive plate (20) are each planar. [2] Lighting device (1) for emitting illuminating light (6), with a pump radiation source (2) for emitting a pump radiation (3), a phosphor element (4) for converting the pump radiation (3) into a conversion light, which at least partially forms the illumination light (6), and a transmissive plate (20), wherein the pump radiation source (2), the phosphor element (4) and the transmissive plate (20) are arranged relative to one another in such a way that, during operation, the pump radiation (3) passes through the transmissive plate (20) via two passage surfaces (21, 22), namely a radiation entry surface (21) and an opposite radiation exit surface (22), and strikes an irradiation surface (5) of the phosphor element (4) downstream of the transmissive plate (20), whereupon the illuminating light (6) is emitted at an irradiation surface (7) of the phosphor element (4), wherein the pump radiation (3) strikes the radiation entry surface (21) of the transmissive plate (20) with an impact center direction (25), and wherein the passage surfaces (21, 22) of the transmissive plate (20) are tilted relative to one another such that the pump radiation (3) impinges on the irradiation surface (5) with an incident irradiation center of gravity direction (26) tilted relative to the incident irradiation center of gravity direction (25); and wherein the transmissive plate (20) is a wedge plate and the passage surfaces (21-24) of the transmissive plate (20) are each planar. [3] Lighting device (1) according to claim 1 or 2 with an illumination optics (8) which guides the illumination light (6) emitted at different points on the radiating surface (7) in different spatial directions. [4] Lighting device (1) according to one of claims 1 to 3, in which the passage surfaces (21-24) are tilted relative to one another by a tilt angle of at most 20°. [5] Lighting device (1) according to one of the preceding claims, in which one of the passage surfaces (21-24) of the transmissive plate (20) is parallel to the incident radiation surface (5) and / or the emission surface (7) of the phosphor element (4). [6] Lighting device (1) according to one of the preceding claims, in which the transmissive plate (20) is mounted so as to be movable relative to the phosphor element (4). [7] Lighting device (1) according to one of the preceding claims, wherein the phosphor element (4) and the transmissive plate (20) are provided in direct optical contact with each other. [8] Lighting device (1) according to one of claims 1 to 8, wherein the phosphor element (4) and the transmissive plate (20) are arranged spaced apart from one another via a gas volume. [9] Set comprising a plurality of lighting devices (1) according to one of the preceding claims, which are identical to one another with regard to the pump radiation sources (2), the phosphor elements (4) and their respective relative arrangement, but differ in their respective transmissive plate (20), in each case in a tilt angle of the transmissive plate (20) by which their passage surfaces (21-24) are tilted relative to one another. [10] Method for producing a lighting device (1) according to one of claims 1 to 8, comprising the following steps: - arranging the pump radiation source (2) and the phosphor element (4) relative to one another; - determining the offset (11) of an illuminating light spot (40) on the radiating surface (7), from which the illuminating light (6) is emitted, to a reference point (10) on the radiating surface (7); - providing a plurality of transmissive plates (20a, b, c) which differ in their respective tilt angle by which the passage surfaces (21-24) are tilted relative to one another; - selecting one of the transmissive plates (20a, b, c) depending on the offset such that the greater the offset (11), the greater the tilt angle of the selected transmissive plate (20); - Installation of the selected transmissive plate (20) to at least partially compensate for the offset (11). [11] Method according to claim 10, wherein for the installation of the transmissive plate (20) a predefined distance (30) between the transmissive plate (20) and the phosphor element (4) is specified independently of the offset (11). [12] Method according to claim 10 or 11, wherein the transmissive plate (20) is installed in such an oriented manner that an angle taken between the passage surfaces (21-24) in a sectional plane, which sectional plane is perpendicular to the radiating surface (7) and / or the irradiating surface (5) and includes a connecting straight line (42) from the reference point to the illuminating light spot (40), is equal to a tilt angle by which the passage surfaces (21-24) of the transmissive plate (20) are tilted relative to one another. [13] Use of a lighting device (1) according to one of claims 1 to 8 for lighting, in particular for motor vehicle lighting, in particular in a motor vehicle headlight, in particular for adaptive lighting in a motor vehicle headlight.

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