WO2013139621A1

WO2013139621A1 - Lighting device for generating light with differing emission characteristics

Info

Publication number: WO2013139621A1
Application number: PCT/EP2013/054709
Authority: WO
Inventors: Bernd WÖLFING; Volker Hagemann
Original assignee: Schott Ag
Priority date: 2012-03-22
Filing date: 2013-03-08
Publication date: 2013-09-26
Also published as: DE102012005661A1

Abstract

The invention relates to a lighting device for generating light with differing emission characteristics, comprising an excitation light source for emitting blue excitation light, a beam shaping element and a converter for converting a part of the excitation light. The converter is arranged in the beam path of the excitation light source in order to convert one part of the excitation light into longer wavelength light and to reflect another part of the excitation light. By superimposing the converted light and the excitation light emitted by the converter, a desired, predetermined colour impression can be generated in the short range, whereas the overall emitted light appears homogeneously white in the long range.

Description

Lighting device for generating light with

different emission characteristics

description

The present invention relates to a

Lighting device for generating light with

different emission characteristics, comprising

at least one excitation light source

Beam-shaping element and a converter. It is the

Converter in the beam path of the excitation light source

arranged to convert part of the

Exciting light in long-wave light and the

Reflecting another part of the excitation light, wherein the total remitted light appears white in the far field.

White light sources can be found in numerous applications, for example in the field of medical diagnostics or non-contact measuring methods. Other applications may be in the lighting of buildings. One

Another important application is the

Automotivbereich, such

Lighting devices can be used for example in the headlight or headlights.

Current headlamps in the automotive sector often include LED light sources, as described for example in the document DE 10 2008 031 256 AI, which allow white illumination. As elaborately designed

typically the realization of a sufficient

Cooling or a good dissipation of heat

Light-emitting diode device. Another development aims to connect a light source via a light guide with a lighting device. In this way, light source and

Lighting device are spatially decoupled from each other. For the production of white light, a conversion medium is often used, which is in the field of

Lighting device is arranged. The

Conversion medium, also called a converter, allows a conversion of the incoming radiation with respect to the wavelength, so that white light can be generated in this way.

The patent US 7,356,054 B2 describes such a lighting device. Here, the conversion medium is connected directly to the end of the light guide in order to achieve a high luminance. The suggestion of the

Conversion medium is thus in transmission, that is, the radiation hits the conversion medium on one side and is discharged through another side. A disadvantage may be a relatively high power loss in the

Conversion medium prove, which can lead to heating and high thermal stress of the conversion medium. The heat removal is often difficult even with such an arrangement of radiation device and conversion medium. It's also a simple one

Replacing the conversion medium in case of

Damage just as complicated.

The inventors have set themselves the task, a

Lighting device to develop, which in the

Distant area generated in homogeneous white light, being in the Close range of a different light can be generated.

It would be desirable to continue one

To provide lighting device which generates white light with a sufficiently high efficiency and allows good heat dissipation.

In this case, the lighting device is intended in particular for reflection or projection devices as well

can be used in particular for headlights.

This task is surprisingly simple by a

Lighting device for generating light with

different emission characteristics, comprising

at least one excitation light source

Beam-shaping element and a converter, according to one of the independent claims.

Preferred embodiments and further developments of

Invention are to be taken from the respective subclaims.

The invention accordingly relates to a lighting device for generating light with different

Radiation characteristic, comprising an excitation light source for emitting blue excitation light, a

Beam shaping element and a converter for converting a portion of the excitation light.

The illumination device accordingly comprises at least one radiation source for emission of electromagnetic

Radiation. The output from the radiation source Electromagnetic radiation is in the context of the invention as excitation light and the radiation source as

Excitation light source called.

A first part of the excitation light can be converted into longer wavelength light. Therefore, converted light having a first emission characteristic can be emitted, and another part of the excitation light can be emitted with a second emission characteristic, so that light is transmitted through the illumination device

different emission characteristics can be generated.

By superimposing the converted light and the excitation light emitted by the converter, a desired, predetermined color impression can be generated in the near zone, whereas the total emitted light appears homogeneously white in the far field.

The converter can be used for transmission and / or remission of the excitation light.

The converter relates to an assembly comprising

Conversion medium for the conversion of electromagnetic radiation, which further may have a grain structure for scattering the excitation light. In addition, a coating, preferably an AR coating, may be provided in order to reduce unwanted reflections of the excitation light and / or the converged light at the interfaces of the conversion medium. The AR coating is preferably arranged on the side of the converter facing the excitation light. Furthermore, on the side facing away from the excitation light of the converter, a mirror or a mirror coating

be provided. A rear-side mirror is particularly suitable for a remission of the excitation light.

Likewise, on the front side, ie on the side facing the excitation light, a filter, in particular a

Short-pass filter for blue light, provided which is permeable to blue excitation light, but converted, long-wave light to one

mirrored opposite exit side. Such an arrangement is particularly favorable for a transmission of the calling light.

The radiation characteristic of the radiated

Excitation light can be influenced by different sizes. In particular, the emission characteristic of the emitted excitation light can be determined by the scattering properties and / or the surface condition and / or the thickness and / or the shape and / or the geometric position of the interfaces of the converter.

Thus, the grain structure of the conversion medium can influence the nature and extent of the scattering of the excitation light.

Furthermore, the surface condition can influence the scattering of the blue excitation light on the light entry side, wherein, for example, a scattering layer can be applied to the converter or the

Exciting light facing surface of the converter is designed with a certain roughness. The thickness of the converter, thus the path length of the radiation of the excitation light in the conversion medium, can

Scattering and thus the radiation of the

Influence excitation light.

Furthermore, the geometric shape of the converter, in particular the orientation of the excitation light facing and the excitation light opposite sides of the converter to each other, influence the emission characteristic. Particularly advantageous, the converter can also be wedge-shaped, so that the

Exciting light facing and the opposite side do not lie on parallel planes.

The formation of the interface, that is, the surface of the converter, can also be beam-forming and thus the emission characteristic of the radiated

Influence excitation light. Thus, for example, the rear interface, that is, the side facing away from the excitation light source of the converter, be formed crowned.

The emission characteristic of the emitted, converted excitation light can also be determined by the variables mentioned above, in particular by the

Scattering properties and / or the surface texture and / or the thickness and / or the shape and / or the

geometric position of the interfaces of the converter. The degree of conversion can be influenced in particular by the thickness of the conversion medium, wherein the thickness can be selected in particular in relation to the absorption length of the excitation light.

The lighting device further comprises a

Beam shaping element, which is preferably provided in the beam path or the illumination direction of the converter for shaping the converted excitation light and the emitted excitation light.

The beam-shaping element can particularly advantageously comprise a plane mirror and / or a curved mirror, for example a parabolic concave mirror, and / or a lens.

In a particular embodiment, the

Lighting device further comprises an optical element, which in the illumination direction in the vicinity of the

Beam shaping element is provided.

Within the meaning of the invention, a proximity to the illumination device, in which the position of the beams from the beam-shaping element of the

Exit point depends on the beam-shaping element and spatially different for a viewer is perceptible. Typically, this area is in one

Distance from the illumination device, which is smaller than ten times the value of the expansion of the

Beam-shaping element. As an extension, for example, the diameter of the beam-shaping element can be assumed. For the purposes of the invention, a distance to the illumination device is to be understood as the distance range, in which the position of the beams essentially depends on the exit angle of the illumination device

Radiation depends on the beam-shaping element. By superimposing and mixing the converted light and the emitted excitation light, a homogeneous light can be generated.

In a particular preferred embodiment, the optical element may have scattering properties.

In this way, in the close range, an optical

Perceptible color impression are generated, which differs from the visually perceptible color impression in the far range. In particular, it is the optically perceptible

Color impression in the far range predominantly homogeneous, whereas in the near range different color impressions can be generated in relation to the color and brightness visually perceptible to a viewer.

The color impression can be generated at an interface of the optical element. But it can also be generated in the volume of the optical element, in addition, a spatial, so three-dimensional effect can be effected.

In another embodiment, the color impression in the vicinity by a corresponding formation of the

Beam shaping element generated, causing a

additional optical element can be dispensed with.

For this purpose, the beam-shaping element by a special surface structure, for example by a certain Roughness of the side of the radiation facing

Beam shaping element, be formed.

In a projection device can on one of

outside the device visible lens on one

Surface, in particular on the light exit side of the lens, a special surface structure, for example, by a certain roughness of the radiation

facing side in a reflector, be formed. In another embodiment, the lens may also have a scattering in its volume, for example by the inclusion of particles. The color impression can thus be effected by scattering in or on the beam-shaping element. A predefined color impression can be effected by a spatial distribution of locations of different color coordinates, brightness and / or emission characteristic in the optical element, it being possible to determine the color coordinates on the basis of the CIE standard valence system and the brightness on the basis of the luminance. In the near range, therefore, a light heterogeneous with regard to the color coordinates and / or the brightness for a viewer can be generated. The excitation light source of the illumination device may include a light source for generating monochromatic light, the light source preferably in the blue

Spectral range emitted. The light of the monochromatic light source can be generated by a laser.

The invention is therefore a

Excitation light source, in particular a monochromatic light source, wherein the monochromatic light by a Laser can be generated. The blue spectral range of the radiation emitted by the excitation light source is understood to be that wavelength range which

predominantly below 500 nm, preferably below 480 nm and more preferably below 470 nm.

In a preferred embodiment, the

Light source at least one semiconductor laser or a

Laser diode, which can achieve very high power densities.

The excitation light source may further comprise an optical waveguide having a radiation emitting end. At the opposite end of the optical waveguide excitation light of the

Excitation light source can be coupled. Particularly preferred may be in the optical waveguide

electromagnetic radiation in the blue spectral range are coupled.

In this way, the excitation light source of the

Lighting device are spatially separated. This can be advantageous if the excitation light source can not be placed in or in the direct area of the illumination device, for example because of the space available.

Furthermore, in this way the excitation light source can also be thermally decoupled from the illumination device and thus be cooled better. In addition, it is possible to supply a plurality of illumination devices according to the invention with excitation light with only one excitation light source. For this purpose, the excitation light can for example be coupled in parallel into at least two or more optical light guides. The optical

For this purpose, the light guide may also include a beam splitter having an input-side end and at least two or more output-side ends. To achieve a particularly high luminance,

In particular, to achieve a particularly high performance, it is also possible excitation light of several

To couple excitation light sources in an optical waveguide. But it is also possible excitation light from multiple excitation light sources over several optical

Light guide to the lighting device to

transport and broadcast to the converter.

The optical fiber can be used in a special

preferred embodiment comprise a fiber optic light guide. Typically, such light guides include a core and a cladding region having different refractive indices and capable of directing electromagnetic radiation, for example by reflection.

Preferably, the optical fiber is designed to conduct blue and / or ultraviolet electromagnetic radiation. Other types of fiber optic light guides may be used, including

Gradient index fiber light guides or photonic ones

Crystal fiber light guides. In the case of using a fiber bundle can by means of beam shaper or diffractive optical elements, the

Intensity distribution of the electromagnetic radiation of the excitation light source are adapted such that when coupled into a fiber optic light guide each fiber of a fiber bundle receives the same radiant energy.

The excitation light source is preferably with a

Carrier firmly and detachably connected. The

Supporting device can therefore be formed with fastening means for positioning and fixing the excitation light source, whereby a simple and secure

Replacing the excitation light source can be made possible. For this purpose, the support device, for example, with positioning aids, such as stops or pins, for

Recording the excitation light source may be formed.

For receiving one or more optical light guides, the support device may advantageously be formed with grooves or grooves, in which the optical light guide can be inserted and fixed with a hold-down. V-grooves, which are particularly suitable for high-precision positioning of optical light guides, have proven particularly suitable for this purpose. In this way, a stable guidance of mechanically unstable optical light guides can be made particularly favorable. By means of a hold-down, the optical

Fiber optics are fixed. An exact, highly accurate spatial positioning and

Orientation of the excitation light source with respect to the Conversion medium is very important to one exactly

irradiate certain area of the converter.

The positioning and orientation of the

Excitation light source is preferably such that the excitation light is emitted in the direction of the converter.

For a high luminance, it is favorable if a

the largest possible proportion of the excitation light one

irradiated as small as possible area of the converter. The area of the surface of the converter, directly in the

Beam path of the excitation light is, hereinafter also referred to as a light spot. For a highly efficient lighting device exact positioning of the light spot is necessary, therefore, the exact location of the light spot in relation to positioning of the

Lighting device or the carrier device of very high importance.

To achieve a high luminance and high efficiency, the formation of a small as possible

Luminous spots and the lowest possible shading by the light supply of great importance, with a small size of the lighting device and a smaller

mechanical effort for exact positioning of great advantage.

The luminance and the efficiency can be influenced by the distance between excitation light source and converter, the size of the excitation light source and the NA of the excitation light. Due to the geometrical arrangement of the excitation light source and the conversion medium, the disadvantage may arise that the excitation light source lies in the region of the beam path, ie along the optical path, of the secondary radiation, if the emission of the converter is in remission. This can lead to unwanted shadowing effects, since the excitation light source and / or the carrier device can lie in the beam path of the secondary radiation.

To minimize these unwanted shadowing effects, the distance between excitation light source and

Conversion medium can be increased. However, an increase in the distance can lead to a significant loss

Lead luminance, since with increasing distance typically the light spot is increased and the luminance decreases accordingly.

The inventors have found that a lower

Distance and low shading can be achieved when the converter is rotated by a certain angle in relation to the optical path of the excitation light, so that the excitation light obliquely impinges on the surface of the converter and remitted light in

essentially not directed to the excitation light source and / or the carrier device.

To achieve a particularly compact and mechanically simple design for the remission of excitation light, which allows a particularly high accuracy of the position of the light spot, in a particular embodiment, the excitation light source and the converter on a be arranged common carrier device, wherein the converter can be aligned obliquely to the optical path of the excitation light. Particularly good experiences have been made at an angle between the optical path of the excitation light and a normal to the surface of the conversion medium in a range of 30 ° to 75 °.

In the context of the invention, a conversion medium of the converter is a material for optical conversion

Understood. Such materials typically contain phosphors which, as optically active media, are the

Conversion effect.

The conversion medium can convert excitation light into longer-wave light such that a portion of the

Excitation light is converted into long-wave, yellow light and a further proportion is scattered and / or reflected as blue light. A first share of the

Excitation light can therefore be in a yellow

Spectral range to be converted.

Furthermore, a fraction in the green spectral range of the converted yellow light can be filtered out so as to obtain a white color locus of the remitted light in the far field, when the color line between the color locus of the excitation light and color locus of the

converted light does not cut the desired white color location, but deviates upward in CIE-y. If the color line is below this range, ie therefore the CIE-y is too low, a red component can also be filtered out. The conversion medium can be used to generate

White light in the long range advantageously be designed so that it is particularly good for a remission

electromagnetic radiation in the blue and / or

ultraviolet spectral range is suitable.

As a suitable material for the conversion medium has an optoceramic material with embedded

Grain structure for a use of excitation light in the blue spectral region proven.

Particularly preferably, the conversion medium comprises a low-doped, in particular less than 0.2 wt .-% doped Ce: YAG phosphor material. A low doping is advantageous in terms of avoiding

Concentration quenching.

The use of a gadolinium-free optoceramic conversion medium may also be advantageous because of the comparatively high heat resistance.

Particularly preferably, an optoceramic material of Ce: YAG with a thermal conductivity of at least 5 W / (m * K) can be used to achieve particularly high luminance. Thus, such conversion media, for example, at temperatures above 200 ° C without

Impairment of the conversion properties or without damage can be used.

Further suitable materials have been found to be phosphorus materials based on Ce: AG and / or Ce: LuAG. The attachment of the excitation light source and the converter on a common carrier device can be of great advantage in terms of highly accurate positioning of the two components to each other and the realization of a very compact design.

The carrier device and / or the holder for attaching the converter may be preferred for a good

Heat dissipation be formed. For this purpose, the

Carrier device and / or the holder, for example, have cooling ribs. But they can also be thermally connected to a heat sink. In a further preferred embodiment, the

Excitation light source comprise an optical light guide with a spatially separated excitation light source. So a defective excitation light source can be easily replaced without the lighting device must be dismantled.

Due to the compact design, the

Lighting device can also be installed rotatable or movable in one or more degrees of freedom to effect a change in the direction of illumination, for example, for an adaptive light.

In one embodiment of the invention, an optical element for focusing in the beam path between the

Excitation light source and the converter can be arranged. This allows the excitation light on the converter

be focused, which makes a particularly small Light spot generated and the luminance can be improved. For optimum conversion, the focus of the excitation light can thus lie within the conversion medium. The object of the present invention further relates to a headlamp for lighting, which a

Lighting device according to the invention and a

Reflector includes. In this case, the lighting device is designed such that the light spot is arranged at the operating point of the reflector.

Likewise, the lighting device can also be used for a projector, wherein the light spot in

Operating point of a lens system of the projector can be arranged.

Furthermore, the invention relates to a headlight for use in vehicles, which comprises a lighting device according to the invention. For this purpose, the reflector may be formed as a headlight or the headlight include a lighting device according to the invention such that the light spot of the converter in

Operating point of the headlamp reflector is located. When using the inventive

Lighting device for a headlamp, the converter according to the specifications and guidelines, white light for vehicles to select. For

Vehicle headlights, this is for example in

corresponding ECE regulations and CIE standards. In order to achieve day-like light colors, a color location in the range of 5500 K to 6500 K can be favorable. For this purpose, a conversion medium can be selected which in

Dependence of the radiation spectrum converts the excitation light into a secondary radiation having a white color location corresponding radiation characteristic.

Coherent blue light from a laser light source poses a not insignificant danger to a viewer when he looks directly into the excitation light. That is how it is

For example, this danger when the converter dissolves and excitation light is coupled out directly and enters the environment.

To avoid an uncontrolled leaking

Excitation light, the reflector can therefore with a

be formed so-called jet trap and, for example, comprise an opening through which in the case of

Impairment of the optical system, the excitation light can be discharged without entering the environment. The impairment of the efficiency of the reflector can be minimized when the excitation light source

Excitation light emitted with a small aperture and the opening in the reflector can be kept very small.

Furthermore, the converter can also be spherically polished on its rear side facing away from the excitation light and / or surrounded by a hollow-mirror-like holder so that, in the event of a defect or drop of the converter, the excitation light is reflected back onto the excitation light source. In general, the invention relates

Lighting devices in which a viewer in a close range a first color, optical

Impression, whereas in the far range a homogeneous color impression, in particular a homogeneous white light, is generated.

Further details of the invention will become apparent from the description of the illustrated embodiments and the appended claims.

The drawings show:

Figure 1 is a schematic side view of

Lighting device

Figure 2 is a schematic plan view of a

Carrier device,

Figure 3 is a view of an obliquely arranged

Conversion medium with a coating,

Figure 4 is a schematic arrangement of a

Lighting device and a reflector, Figure 5 shows a further schematic arrangement of a

Lighting device and a reflector, Figure 6 is a schematic arrangement of a

Lighting device with a beam trap, Figure 7 shows a further schematic arrangement of a

Lighting device with a beam trap and

Figure 8 shows an embodiment, the setting

a white-field near point in the color spectrum diagram allows. Detailed Description of Preferred Embodiments In the following detailed description

For the sake of clarity, preferred embodiments denote substantially identical parts in or on these embodiments. Figure 1 shows a schematic side view of a

Lighting device according to the invention in cross section. The excitation light source comprises an optical

Light guide, the fiber optic light guide 14th

is formed and coupled into the electromagnetic radiation of an excitation light source 18. Of the

Light guide 14 emits coupled electromagnetic radiation as excitation light at its one end 15 in the direction of a converter 11. The carrier device 10 is provided in the region of the attachment of the converter 11 with a mirror coating 12. This can be, for example, a coating of the corresponding contact surface 17. Furthermore, the holder can also be equipped with a mirror or a metallic mirror

be educated.

A hold-down 13 serves to fix the at least one optical waveguide 14. A strain relief (not shown) can be used to secure the fiber optic

Be provided light guide. Particularly low, the hold-down 13 is formed very flat to minimize shading. One

Downholder 13 is not mandatory;

For example, the optical waveguide 14 may also be glued in or on the carrier device.

Figure 2 shows a schematic plan view of a

Carrier device 10, comprising a converter 11.

A total of three grooves or grooves 20 are provided to fiber optic light guide (not shown) as

To record excitation light source. Particularly favorable are the grooves or grooves 20 as so-called V-grooves

trained, which is a very good reception of

fiber optic light guides without damaging them. The presence of three receiving options for optical fibers is a possible embodiment, but is not mandatory for an inventive

Lighting device. Rather, the number of optical light guides depends on the requirements of the particular use, for example, the luminance to be achieved or the temperature of the excitation light source to be tolerated.

The excitation light of the excitation light sources is particularly advantageous at a common point on the converter 11, which represents the light spot 22. To achieve high efficiency and / or high

Luminance is to keep the spot 22 as small as possible.

The support device 10 is further formed with openings and / or holes 21 for attachment with other objects such as a reflector (not shown). For a highly accurate positioning and / or orientation of the support device, this can be formed, for example, with oblong holes 25 and holes 24 for dowel pins.

FIG. 3 schematically shows a cross-sectional view of a converter, with excitation light 63 impinging obliquely on the converter.

The carrier device 16 is in the region of attachment to the conversion medium 11 with a broadband

reflecting mirror 62 is formed. This can also be a broadband reflective coating of

Carrier device 16 be. The converter 11 is on the surface facing the excitation light with a as

Bandstopfilter acting layer 61 formed having a certain proportion in the converted yellow light

reflected, so that the converted radiation can be filtered in a certain wavelength range

The reflected or backscattered blue spectral component and the converted filtered yellow spectral component produce white illumination light in their mixture. In addition, this layer 61 can also be formed with an AR coating in order to reduce a reflection of excitation light and / or converted light and in this way Improve conversion efficiency. The direction of propagation 72 of the yellow light converted by the conversion medium 11 corresponds approximately to a Lambert 'emitter, while reflected or scattered blue or ultraviolet light is emitted approximately in a certain beam direction 64.

FIG. 4 shows a schematic arrangement of a

Lighting device according to the invention within a reflector 71. The conversion medium 11 is in

Work area of the reflector 71 is arranged, wherein the reflector 71 is arranged in the illumination direction of the converter 11. The reflector 71 is formed as a parabolic half-concave mirror. The converter 11 is arranged obliquely to the excitation light 63.

The beam cone of the reflected or scattered blue light is determined by its outer boundary 81, 82. The blue light is reflected at the reflector and emerges from the reflector essentially collimated. The

Beam paths 83, 84 show the outer boundaries of the blue, collimated light of the imaged ones

Embodiment. An optical device 85 is in

Beam path of the reflector formed. The optical

Device 85 may, for example, as a cover of the

Reflector be formed.

This can be a Fresnel surface or a rough one

Have interface to allow a diffuse scattering of the light.

A view of the optical device in the direction of the reflector 71 is shown in FIG. 91. In the illustrated embodiment, an observer looking from outside onto the optical device sees in the near zone an approximately homogeneous, first surface 93, which may appear yellowish or white, as well a spatially separated second surface 92, which appears substantially blue and is circular in shape. The second area 92 acts on a viewer in the near field blue.

In this way, an optical color impression can be effected for a viewer in the near field, which can correspond to a so-called "laser pupil". In the far range, however, such a lighting device can generate a white light.

FIG. 5 shows a further preferred embodiment, in which the excitation light 63 is perpendicular to the

Surface of the conversion medium 11 impinges. The

Excitation light source is therefore in the beam path of the remitted from the conversion medium radiation, whereby a shading occurs. The reflector is designed as a parabolic concave mirror 86. An observer looking from outside onto the reflector 86 may have in the near area an approximately homogeneous, first surface 93, which may appear yellowish or white, as well as a spatially separated second surface 92, which in the

essential blue appears, recognize. The second area 92 acts on a viewer in the near field blue. Due to the vertical impingement of the excitation light 63 on the conversion medium 11, the second surface 92 is located in the center of the illuminated surface 91. Due to the shading, a central third surface 94 can be seen, which in

Near range is significantly less illuminated, so has a lower brightness. In this way, for example, a so-called

"Angel Eye" effect can be generated for a viewer in close range. In the remote area, such

Lighting device, however, generate a white light.

FIG. 6 shows a development of the invention, comprising an optical lens 101 for focusing the

Excitation light 63 is shown schematically on a surface of the conversion medium 11. Schematically depicted

Furthermore, a beam trap 102, which as a concave mirror on the side facing away from the excitation light source side of

Conversion medium is provided. In the event of a defect or decay of the conversion medium, the blue light reflected or scattered in the direction of the excitation light source, which is harmful to the environment, can thus be detected

be reflected back.

FIG. 7 shows a further development of the invention, in which a beam trap 102 is provided outside a reflector 71 at a location on which reflected or scattered blue light falls in the event of a fall of the conversion medium 11.

A further embodiment will be described with reference to FIG. 8, which shows the setting of a white field near

Point in the color spectrum diagram allows. For the

Remissionsbetrieb the converter 11 is provided with a mirror 31. In order to get close to the white field on the conversion line in the color spectrum diagram, the converter 11 is selected with regard to its scattering properties so that 20% of the blue excitation light is remitted and 80% absorbed. For the transmission mode, the converter 11 is selected so that 20% of the blue excitation light after

Penetrating the converter is emitted on a side opposite the entrance side.

The absorbed portion of the excitation light is largely converted into yellow light and emitted as a scattering lobe 51 either directly or after reflection at the mirror 31.

The blue remitted light is composed of a Fresnel reflex 40 and a scattering lobe 41 together. These

Litter 41 has a Lambert 'see

Radiation characteristic on.

A shift of the white field near point now takes place via the adaptation of the converter thickness. If this is so small that excitation light is reflected at the mirror 31 and exits again at the surface, this results in a

second scattering lobe 42. This second scattering lobe 42 has - depending on the converter thickness and scattering - a more or less directional radiation characteristic. The superposition of the scattering lobes 40, 41, 42 of the excitation light and the scattering lobe 51 of the converted light creates a

Angular dependence of the color impression. The

Angular dependence can be caused by roughening the

Converter surface can be reduced.

The fine adjustment for reaching the white-field-near point can alternatively take place via the application of a thin scattering layer on the excitation side of the converter 11. The scattering layer can be made, for example, from T1O ₂ or undoped, consist of optoceramic material. In both cases, the blue component is increased compared to the yellow component of the emitted light.

To get into the white field of the color spectrum diagram, one can deplete the yellow light on green fractions by filtering. This can be done for example by a

reach the dichroic mirror, which reflects the blue light, but allows the incident green light to pass, so that this is not on the useful side of the

Converter exit.

It will be apparent to those skilled in the art that the invention is not limited to the merely exemplary embodiments described above with reference to the figures, but can be varied in many ways within the scope of the subject-matter of the claims. In particular, the features of individual embodiments can be combined.

Claims

claims

1. Lighting device for generating light with different emission characteristics, comprising - an excitation light source for emitting blue

Excitation light,

a beam-shaping element,

a converter for converting part of the excitation light,

wherein the converted light with a first

Radiation characteristic is emitted and the

Exciting light with a second

Emission characteristic is emitted,

in which by superimposing the converted light and the excitation light emitted by the converter in

Close range a given color impression is generated, and

wherein the total radiated light in the far range appears homogeneous white.

2. Lighting device according to claim 1, wherein the second emission characteristic of the excitation light by the scattering properties and / or the

Surface texture and / or the thickness and / or the shape and / or geometric position of the

Interfaces of the converter is determined.

3. Lighting device according to claim 1, wherein the first emission characteristic of the converted light by the scattering properties and / or the

Surface texture and / or the thickness and / or the shape and / or geometric position of

Interfaces of the converter is determined.

Lighting device according to one of the preceding claims, wherein the beam-shaping element a

Plan mirror and / or a curved mirror and / or a lens comprises.

Lighting device according to one of the preceding claims, wherein an optical element in

Lighting direction in the vicinity of the

Beam shaping element is arranged.

Lighting device according to one of the preceding claims, wherein the optical element scattering

Features.

Lighting device according to one of the preceding claims, wherein a predetermined color impression is generated by the optical element.

Lighting device according to one of the preceding claims, wherein the color impression caused by scattering in the volume of the optical element and / or generated by scattering at an interface of the optical element.

Lighting device according to one of the preceding claims, wherein the color impression by a spatial distribution of different locations

Color coordinates, brightness and / or

Abstrahlcharakteristik is given. Lighting device according to one of the preceding claims, wherein the excitation light source a

includes monochromatic light source.

Lighting device according to one of the preceding claims, wherein the excitation light source comprises an optical light guide.

Lighting device according to one of the preceding claims, wherein the converter converts excitation light into longer-wavelength light.

Lighting device according to one of the preceding claims, characterized in that the converter is a Ce: YAG and / or a Ce: AG and / or Ce: LuAG

Includes phosphor material.

Lighting device according to one of the preceding claims, characterized in that a

Carrier device for fixing the converter and / or the excitation light source and / or the

Beam shaping element is provided.

Lighting device according to one of the preceding claims, characterized in that the

Support device at least in the field of attachment of the converter for heat dissipation and / or as

Heat sink is formed.

Lighting device according to one of the vorstehe

Claims, characterized in that a Beam trap is provided for reflecting reflected or scattered blue light in a direction that is harmless to the external environment.

17. Projection device comprising at least one

Lighting device according to one of the preceding claims, wherein the converter, in particular the

Luminous spot of the converter, at the operating point of the

Projection device is arranged.

18. Headlamp comprising at least one

Lighting device according to one of the preceding claims 1 to 16, wherein the converter, in particular the luminous spot of the converter, is arranged at the operating point of the headlamp.