WO2018077577A1

WO2018077577A1 - Lighting device

Info

Publication number: WO2018077577A1
Application number: PCT/EP2017/075120
Authority: WO
Inventors: Krister Bergenek
Original assignee: Osram Gmbh
Priority date: 2016-10-28
Filing date: 2017-10-04
Publication date: 2018-05-03
Also published as: DE102016221354A1

Abstract

A lighting device (1) comprises at least one first semiconductor light source (6) for emitting a first light beam (L1) composed of light of a first wavelength (λ1), at least one second semiconductor light source (7) for emitting a second light beam (L2) composed of light of a second wavelength (λ2), and a phosphor volume (2) which can be irradiated by the first light beam (L1) and the second light beam (L2) and serves for converting at least the light of the first wavelength (λ1) into the same secondary light (S), wherein the first wavelength (λ1) and the second wavelength (λ2) differ and the phosphor volume (2) has a higher degree of conversion (K) for the conversion of the light of the first wavelength (λ1) into the secondary light (S) compared with the conversion of the light of the second wavelength (λ2) into the same secondary light (S). The invention is applicable in particular to spotlights or headlights (H), for example for vehicles, effect lighting systems, exterior lighting systems or general lighting systems.

Description

BELEUCHTU GSVORRI CHTU G

DESCRIPTION

The invention relates to a lighting device,

comprising a phosphor volume, at least one first semiconductor light source for emitting a first

Light beam of light of a first wavelength on the phosphor volume, and at least a second

Semiconductor light source for emitting a second

Light beam of light of a second wavelength on the phosphor volume. The invention is particularly applicable to headlights, for example for vehicles,

Effect lighting, exterior lighting or

General lighting.

In so-called LARP applications ("Laser Activated Remote Phosphor") applications, a blue primary light (pump light), which is generated by a laser, is usually blasted onto a volume of phosphor. The

Fluorescent volume partially converts the blue primary light into yellow secondary light. The yellow secondary light and the unconverted, scattered proportion of the blue primary light are emitted by the volume of phosphor mixed as yellow-blue or white useful light.

In LARP applications, it may be in a case of damage in which the volume of the phosphor is damaged or the

Fluorescent volume even dissolves completely, resulting in an unwanted leakage of unscattered laser light. Also, a local color distribution of the useful light at the surface of the phosphor volume is sometimes not homogeneous, but shows bluish and / or yellowish color shifted areas.

There are two ways to ensure eye safety, which can also be used in combination.

One way is to use so-called light traps. In the event that the volume of the fluorescent material is damaged and

unscattered, directed laser radiation escapes, this becomes Laser radiation caught in the light trap and does not emerge from the lighting device. One problem with this is that the light trap is also present in normal operation and collects light. This means that, depending on the optics concept, a not inconsiderable part of the useful light is already blocked by the light trap during normal operation. One

Another problem of the light trap solution is potential

Reflections on a damaged phosphor volume. It is conceivable that a damaged volume of phosphor can leak unscattered laser radiation and deflects this radiation from the optical axis. This is the function of

Light trap is no longer guaranteed.

Another way is to provide protection at the module level, e.g. on a LARP module. In this case, a composition of the light emerging from the phosphor volume is monitored. Damage to the

Fluorescent volumes should change due to a change in

Spectrum of the emitted light noticeable. However, such systems are usually difficult to control. To keep costs down, expensive sensors should not be used. Another problem is reliably measuring the light to avoid damage to the light

To recognize fluorescent volume. At the same time, the protective device should be so robust that no false alarms are emitted during normal operation.

It is the object of the present invention to at least partially overcome the disadvantages of the prior art, and in particular a semiconductor lighting device

provide that is simple and inexpensive to implement, behaves safely in the event of damage of the phosphor volume and / or a particularly homogeneous color

Generated useful light.

This object is achieved according to the characteristics of the independent

Claims solved. Preferred embodiments are

in particular the dependent claims. The object is achieved by an illumination device, comprising at least one first semiconductor light source for emitting a first light beam of light of a first wavelength, at least one second semiconductor light source for emitting a second light beam of light of a second wavelength and a can be irradiated by the first light beam and the second light beam phosphor volume for converting at least the light of the first wavelength into secondary light, wherein the first wavelength and the second wavelength differ and the volume of phosphor for converting the light of the first wavelength into the secondary light has a higher degree of conversion than for converting the light of the second wavelength into the second wavelength same secondary light, that is in secondary light with the same wavelength or from the same

Wavelength range.

This illumination device has the advantage that a local color inhomogeneity of the useful light emitted by the volume of phosphor can be considerably reduced or even practically completely compensated. It is exploited that the light of the second wavelength is basically independent of the light of the first wavelength on the

Fluorescent volume is radiant and thereby a

Light emission of the light of the second wavelength of the phosphor volume targeted to reduce the

Color inhomogeneity is adjustable.

Thus, the phosphor volume converts the incident light of the first wavelength to a higher degree of conversion

Secondary light around as the incident light of the second

Wavelength. If a degree of conversion of the

For the second wavelength light source, the light of the second wavelength is partially converted to the same secondary light as the second volume light

Light of the first wavelength, in particular by the same phosphor. If a degree of conversion of the

Fluorescent volume for the light of the second wavelength is zero, the light of the second wavelength by the Phosphor olumen not converted. In other words, the light of the second wavelength is detected by means of the

Fluorescent volume with a lower degree of conversion converted into the same secondary light as the light of the first wavelength, or the light of the second wavelength is not converted by the volume of phosphor.

In this lighting device, from one side of the phosphor volume (hereinafter without limitation of the

Generality referred to as "front") both the

Secondary light, the (of the phosphor volume only scattered) light of the second wavelength and optionally a (then also scattered by the phosphor volume) unconverted portion of the light of the first wavelength

mixed emitted as useful light.

It is a continuing education that the first one

Semiconductor light source and the second semiconductor light source are independently controllable. Also, in one embodiment, the first light beam and the second

Light beam independently adjustable, e.g. by a corresponding adjustment respectively associated optics. Alternatively, the semiconductor light sources may be followed by a common optical system.

The volume of phosphor comprises at least one phosphor capable of absorbing the (primary) light of the first wavelength at a higher degree of conversion

To convert secondary light as the light of the second

Wavelength. The wavelength of the secondary light is

typically longer than the wavelength of the incident light of the first and the second wavelength (so-called "down conversion"). For example, blue light can be converted by the phosphor into green, yellow, orange or red secondary light. A conversion or

The degree of conversion depends, for example, on a thickness and / or a phosphor concentration of the phosphor. It is also possible that the volume of phosphor more

has different phosphors to the light of first wavelength with a higher degree of conversion in

To convert or convert secondary light than for the second wavelength light. The volume of phosphor can be translucent

Matrix material distributed over embedded phosphor particles, e.g. Powder particles. The matrix material may be e.g. Silicone, epoxy or glass. The

Fluorescent volume can also be made from a uniform

Wavelength-converting bodies, for example of wavelength-converting ceramics such as YAG: Ce (eg doped with gallium), LuAG: Ce, Ga doped LuAG: Ce, LiEuMo ₂ 0s or Li3Ba2Eu3 (M0O4) 8 · The volume of phosphor can be

platelet-shaped phosphor volume or a

platelet-shaped phosphor body.

A wavelength may, in particular, be understood as a peak wavelength of an associated spectrum. The spectrum is especially narrowband. The spectrum is particularly spit zenförmig. The first wavelength or its spectrum can be practically disjoint from the second wavelength or its spectrum.

It is a further development that the degree of conversion for the light of the first wavelength is at least 90%, in particular at least 95%, in particular at least 98%, in particular 100% (full conversion). It is a continuing education that the degree of conversion for the light of the second

Wavelength is not more than 70%, in particular not more than 50%, in particular not more than 30%, in particular not more than 20%, in particular not more than 10%,

in particular about 0% (no conversion). The degree of conversion may also be different for a spectrum. So can for a spectral peak with a certain width the

Conversion degree within this width with increasing

Wavelength or increase with decreasing wavelength.

Consequently, for example, for the light of the second wavelength, a degree of conversion between X% and Y% may vary, eg between 15% and 65%. It is still a development that that of the Phosphorolumen by conversion or conversion of

First wavelength light generated secondary light by conversion or conversion of the light of the second

Wavelength generated secondary light is the same, e.g. has the same wavelength.

It is an embodiment that the illumination device has a transparent to the light of the first wavelength and the light of the second wavelength carrier, at the front of a volume of phosphor present - in particular attached - and the first light beam and the second light beam through the carrier on a Rear side of the phosphor volume are radiant. This structure may also be referred to as a "transmissive" structure. The transmissive structure gives the advantage of a

particularly easy to implement and robust construction with particularly low light losses.

In the transmissive structure is thus the

Fluorescent volume at its back irradiated both by the light of the first wavelength and the light of the second wavelength. At the front of the

Fluorescent volume are emitted mixed both the secondary light, the - scattered only by the phosphor volume - light of the second wavelength and possibly - then also scattered by the phosphor volume - unconverted portion of the light of the first wavelength. This mixed light can be coupled out as useful light from the lighting device, e.g. via a coupling-out optics.

Consequently, a first focal spot can be generated at the rear side of the phosphor volume (which is opposite a front side of the carrier) by means of the first light beam and a second focal spot can be generated by means of the second light beam. As a focal spot can be understood in particular an area on a surface of the phosphor volume, the light of a light beam with a

given minimum strength, minimum intensity or similar incident. The outer edge of the focal spot corresponds to a line of this Minimum thickness. The focal spot may be contiguous or may comprise a plurality of separate subregions.

As an alternative to the transmitting structure, a

reflective structure can be used, wherein the first light beam and the second light beam on the front of the phosphor volume, of which also the useful light

is radiated, are einstrahlbar. The carrier rear-side relative to the phosphor volume can then be reflective for the light of the first wavelength and for the light of the second wavelength.

Mixed forms are also possible in which e.g. the first light beam can be irradiated onto the back side of the phosphor volume by a transparent support and the second light beam can be directed onto the front side of the fluorescent material

Fluorescent volume is einstrahlbar. In this case, the carrier for the light of the second wavelength reflective

be educated. This hybrid form may also be reversed with respect to the first and second wavelength light

be educated.

It is still an embodiment that on a rear side of the phosphor volume by means of the first light beam, a first focal spot and by means of the second light beam, a second focal spot can be generated and one of the focal spots completely surrounds the respective other focal spot. This embodiment has the advantage that color inhomogeneities of the light emitted at the front of the phosphor volume can be reduced particularly effectively. This is based on the knowledge that the front of the

Fluorescent volume emitted light often a central area with an increased proportion of light of the first

Wavelength and / or an outer annular region having an increased proportion of the light of the second wavelength. For example, at a blue first

Wavelength central increased blue ("blue cast") and yellow secondary light an outer area with an increased yellow part ("yellow cast") occur. By the additional impingement of only the second wavelength light outside of the first focal spots may do so

Color inhomogeneity be balanced. That one of the focal spots completely surrounds the respective other focal spot on the backside of the luminescent medium comprises, in particular, that the edge of one, surrounding (larger, outer) focal spot is spaced from the edge of the other, surrounded (smaller, inner) focal spot. The edges do not coincide. The surrounding

The focal spot may also include a surrounding focal spot with a plurality of separate subregions. The surrounding focal spot then surrounds in each case several subregions of the surrounding focal spot.

In particular, the surrounding focal spot is within the surrounding focal spot. The volume of phosphor is therefore in the region of the surrounding focal spot both by the first light beam and by the second light beam

irradiated. In contrast, in the region between the surrounded focal spot and the surrounding focal spot, the phosphor volume can only be irradiated by the light which generates the surrounding focal spot. The surrounding focal spot may be formed by the light of the second wavelength while the one surrounding it

Focal spot is formed by the light of the first wavelength, or vice versa. It is a development that focuses the focal areas on the phosphor volume with an irradiance of at least a factor of 1 / e or 1 / e ^{2 of} a maximum

Irradiance of these focal spots correspond. Thus, areas of the phosphor volume which are less heavily irradiated than 1 / e or 1 / e ² do not belong to a focal spot and may, in this regard, due to their small size

Irradiance are neglected. It is yet another embodiment that the at least one first semiconductor light source comprises or is at least one laser diode and the at least one second

Semiconductor light source comprises or is at least one light emitting diode. By means of the at least one laser diode, the advantage is achieved that secondary light with a high

Intensity or brightness can be generated. A light-emitting diode is particularly inexpensive. In particular, a field or array of multiple laser diodes and / or a field of multiple LEDs may be used, e.g. in a matrix-like arrangement.

Another advantage arises from the fact that at a

Damage or even detachment of the luminescent medium, the at least one laser diode can be switched off and the at least one light-emitting diode can continue to be operated. This avoids potential eye damage from the coherent, high-intensity laser light of the first wavelength, but emergency lighting by the generally noticeably weaker LED light of the second wavelength

maintained.

It is also an embodiment that the first wavelength and the second wavelength are blue wavelengths. This allows for a wide variety of uses

Phosphors for producing blue-yellow or white mixed light as the useful light, if the secondary light is yellow light.

It is also an embodiment that a distance between the first wavelength and the second wavelength is not more than 30 nanometers, in particular not more than 25 nanometers, in particular not more than 20 nanometers, in particular not more than 15 nanometers. This results in a high color proximity of the first wavelength and the second

Wavelength achieved, which is a very similar color

Create an impression for the human eye. Thus, an impression of a color spatial homogeneity of the useful light is further supported. It is also an embodiment that the first wavelength is about 435 nm and the second wavelength is about 460 nm. This provides the advantage that these two wavelengths can be generated by already available laser diodes or LEDs and also noticeably by phosphors

different degrees of conversion can be provided. The second wavelength may in particular be between 460 nm and 470 nm (peak wavelength). It is also an embodiment that the second light beam can be irradiated onto the phosphor volume with a larger opening angle than the first light beam. This allows a particularly effective color balance in the

Radiation pattern of the phosphor volume in lateral

Space regions, that is, in spatial regions that have a high angle to the main emission direction of the mixed light emitted from the phosphor volume.

It is also an embodiment that at one

Front of the phosphor volume, a light filter is present, which is at least partially reflective for the light of the first wavelength and for the light of the second

Wavelength and the secondary light is permeable. This provides the advantage that a degree of conversion of the light of the first wavelength by at least partially

Back reflection in the phosphor volume can be further increased. In turn, this also allows a thickness of the

Reduce the phosphor volume. Another advantage is that now a

reliable safety function to avoid a

Eye damage is provided by the light of the first wavelength, since the light of the first wavelength is at least partially blocked by the light filter. Even if the volume of fluorescent material is damaged or even no longer present at the intended location, it is thus possible for the light of the first wavelength - in particular

coherent laser light - attenuated by the light filter or even blocked completely. This in turn allows a classification of the lighting device in a

much lower protection class than e.g. Class 4 and is therefore comparatively safe to use. It is a development that the light filter for the light of the first wavelength has a transmittance of 10% or less, in particular ΠΠ 5 "6 or less, in particular of 2% or less, in particular of 0% If the transmittance is 2% or 0%, the light filter can be described as practically fully reflective, which makes it possible to prevent leakage of high-intensity, coherent light radiation particularly reliably, and further protective measures can be dispensed with, which in turn enables a particularly inexpensive lighting device.

However, other protective measures may additionally be provided. Thus, a preferably narrow-band light sensor can be optically connected downstream of the light filter, which detects only the light of the first wavelength (and not also the secondary light or the light of the second wavelength). This light sensor can with a

Be connected security circuit, which is adapted to at least the at least one first

Semiconductor light source, the light sensor should detect a light signal (i.e., light of the first wavelength) above a predetermined threshold.

In a fully reflective embodiment, the decoupled from the lighting device Nutzlicht so only by the secondary light and by the light of the second

Wavelength formed. Since the secondary light and the light of the second wavelength can be generated independently of one another, a desired (sum) color location of the useful light and a locally high color homogeneity can be precisely set, in particular by means of an individual control of the semiconductor light sources. It is still a development that the light filter only in a central area of a front side of the

Fluorescent volume radiatable mixed light is present. This central area also corresponds to an area through which the first light beam passes when the

Fluorescent volume is not present. This development makes it possible to radiate laterally or at a high angle to a main emission axis of the useful light,

To use comparatively weak light of the first wavelength as a useful light component. A central region can be understood in particular to mean a region centered around a main emission axis of the useful light.

It is also an embodiment that the light filter is a dichroic filter, in particular a

Interference filter or dielectric mirror (Bragg mirror). The dichroic filter allows a sharp separation of the light of the first and the second wavelength and a high degree of reflection with simple means. It is sufficient in one development, at an angle of not more than +/- 10% on the light filter incident light of the first wavelength effectively reflect back.

It is also an embodiment that the

Lighting device is a headlamp or part of a headlamp. The headlight can enter

Vehicle headlight, a headlight for one

Stage lighting, a spotlight for one

Effect lighting, a spotlight for one

Outdoor lighting, a spotlight for one

General lighting and so on. The vehicle having the vehicle headlight may be a motor vehicle (e.g.

A motor vehicle such as a passenger car, truck, bus, etc. or a motorcycle), a railroad, a watercraft (e.g., a boat or a ship), or an aircraft (e.g., an airplane or a helicopter).

The above-described characteristics, features and advantages of this invention and the manner in which it achieves become clearer and more clearly understandable in the

In connection with the following schematic description of an embodiment, in connection with the

Drawings are explained in more detail. It can to

Clarity identical or equivalent elements must be provided with the same reference numerals.

Fig.l shows a sectional view in side view

Components of a lighting device; and Fig. 2 shows a plot of wavelength-dependent

Properties of components shown in Fig.l.

Fig. 1 shows a lighting device 1, e.g. in the form of a headlamp H or a module for it. The

Lighting device 1 has a volume of phosphor in the form of a ceramic phosphor plate 2 with exactly one phosphor material. The phosphor plate 2 rests with its rear side 3 on a front side 4 of a translucent sapphire support 5.

The back 3 of the phosphor plate 2 is passed through the sapphire support 5 by means of a first light beam LI of light of a first wavelength λΐ and a second

Light beam L2 irradiated from light of a second wavelength X2. The first light beam LI is generated by means of a first semiconductor light source in the form of at least one laser diode 6 and has a first (peak) wavelength λΐ of e.g. about 435 nm. The second light beam L2 is generated by means of a second semiconductor light source in the form of at least one LED 7 and has a second (peak) wavelength X2 of e.g. about 460 nm.

2 shows the light spectrum of the first light beam LI and the second light beam L2 as a function of the

associated wavelength λ in nm. The first light beam LI is considerably narrowband than the second light beam L2. The two light beams LI and L2 are disjoint, so they do not overlap. Returning to FIG. 1, the at least one

Laser diode 6 and / or the at least one LED 7 a

jet-forming, e.g. focusing, optics 8 and 9 be optically downstream. By the optics 8 and 9 causes the first light beam LI and the second light beam L2 with a respective predetermined opening angle to the

Irradiate phosphor plate 2. Here is the

Opening angle of the first light beam LI smaller than the opening angle of the second light beam L2. In addition, a through the first light beam LI at the back 3 of the

Phosphor plate 2 generated first focal spot Bl smaller than one by the second light beam L2 at the

Rear side 3 of the phosphor plate 2 generated second focal spot B2. The first focal spot Bl lies within the second focal spot B2, so that the second focal spot B2 completely surrounds the first focal spot B1.

The laser diode 6 and the LED 7 can be operated individually. The laser diode 6 and the LED 7 may be e.g.

continuously (in so-called CW mode) and / or clocked, in particular pulse width modulated, operable. Clock rates for the laser diode 6 and the LED 7 can be equal or

be different. As a result, further color settings, in particular by changing a sum color location of the useful light, are possible. The optics 8 and 9 can

be individually adjustable.

The phosphor plate 2 has a higher degree of conversion K for the light of the first wavelength λΐ than for the light of the second wavelength X2. 2 shows the

Conversion degree K as a function of the wavelength λ. The degree of conversion K can e.g. be turned off to a certain thickness of the phosphor plate 2. For the first

Wavelength λΐ, a maximum degree of conversion K is achieved, e.g. of at least 90%, in particular of at least 95%, in particular of at least 98%, in particular of 100%. For the second wavelength X2, however, only one

Conversion degree K between about 15% and about 65% in relation to the maximum degree of conversion K reached, wherein at the Peak wavelength, a conversion degree K of about 40% of the maximum degree of conversion K is achieved.

Returning to Fig.l, the light becomes the first

Wavelength λΐ and the second wavelength X2 of the

Phosphor plate 2 with the respective degree of conversion K in the same yellow secondary light S converted and

predominantly emitted from its front 10. The

Luminous efficiency for the secondary light S can be increased when the sapphire support 5 for the secondary light S

is reflective, e.g. by providing a corresponding dichroic coating. Also, an unconverted portion of the light of the second wavelength X 2 scattered by the phosphor chip 2 is emitted from the front side 10. Optionally, a non-converted, but scattered by the phosphor plate 2 portion of the light of the first wavelength λΐ are emitted from the front side 10.

On the front side 10 of the phosphor plate 2 - and thus optically behind the phosphor plate 2 - is a

dichroic light filter 11 present, e.g. spaced as shown from the phosphor plate 2 or alternatively resting thereon. The light filter 11 is substantially fully reflecting (for example with a transmittance of less than 2%) for the light of the first wavelength λΐ and for the light of the second wavelength X2 and for the secondary light S

permeable, as shown in Figure 2 on the basis of a wavelength-dependent transmittance T. The light filter 11 may be e.g. a glass substrate with a dichroic coating.

Consequently, possibly still from the front 10 of the

Phosphor plate 2 radiated light of the first

Wavelength λΐ back into the phosphor plate 2

reflects where it is convertible again. The remaining behind the light filter 11 yellow-blue or white mixed light from the secondary light S and the light of the second wavelength X2 is reusable as useful light. The useful light X2, S here has a main emission direction perpendicular to the

Front 3 of the phosphor plate 2 on.

If the phosphor plate 2 is damaged or falls off the sapphire carrier 5, the first light beam LI is reflected back from the light filter 11, so that leakage of the first light beam LI from the lighting device 1 is prevented. The laser diode (s) 6 and the LED (s) 7 can on a

common substrate, e.g. a common circuit board, be arranged. In particular, if they are close together, they can use a common look instead of respective optics 8, 9. The optics can be a collimation optics.

The phosphor volume 2 can additionally convert a phosphor to the light of the first wavelength λΐ

Have conversion to red secondary light, e.g. Eu-doped or Eu-activated phosphor mixed with LuAg. Such a phosphor has a significantly higher degree of conversion at 435 nm than at 460 nm.

To further increase eye safety, the

Lighting device 1 further comprising a the

Light filter 11 optically downstream light sensor 12 which detects only the light LI of the first wavelength λΐ. The light sensor 12 is provided with a

Safety circuit 13 is connected, which is adapted to at least the laser diode (s) 6 and possibly also the LEDs 7 off or dim, if the light sensor 12, a light signal above a predetermined threshold

detected.

Although the invention in detail by the shown

Embodiment has been illustrated and described in detail, the invention is not limited thereto and others Variations may be deduced therefrom by those skilled in the art without departing from the scope of the invention.

Generally, "on", "an", etc. may be taken to mean a singular or a plurality, in particular in the sense of "at least one" or "one or more" etc., unless this is explicitly excluded, e.g. by the expression "exactly one", etc.

Also, a number may include exactly the specified number as well as a usual tolerance range, as long as this is not explicitly excluded.

LIST OF REFERENCE NUMBERS

Lighting device 1

Fluorescent plate 2 Back of the phosphor plate 3

Front side of the sapphire support 4

Sapphire Carrier 5

Laser diode 6

LED 7 optics of the laser diode 8

Optic of the LED 9

Front side of the phosphor plate 10

Dichroic light filter 11

Light sensor 12 Safety circuit 13

First focal spot Bl

Second focal spot B2

Headlight H

Conversion degree K First light beam LI

Second light beam L2

Wavelength λ

First wavelength λΐ

Second wavelength X2

Claims

PATENTA'S TEST

Lighting device (1) comprising

at least one first semiconductor light source (6) for emitting a first light beam (LI) of light of a first wavelength (λΐ),

- At least one second semiconductor light source (7) for emitting a second light beam (L2) of light of a second wavelength (λΐ) and

- A by the first light beam (LI) and the second light beam (L2) irradiated phosphor olumen (2) for converting at least the light of the first

Wavelength (λΐ) in secondary light (S),

in which

- the first wavelength (λΐ) and the second

Distinguish wavelength (λ2) and

- the phosphor olumen (2) for the conversion of the

Light of the first wavelength (λΐ) in the

Secondary light (S) has a higher degree of conversion (K) than for the conversion of the light of the second wavelength (λ2) in the same secondary light (S).

Lighting device (1) according to claim 1, wherein

- The illumination device (1) for the light of the first wavelength (λΐ) and for the light of the second wavelength (λ2) transparent carrier (5), on whose front side (4) the

Fluorescent volume (2) is present, and

- The first light beam (LI) and the second light beam (L2) through the carrier (5) on a back side (3) of the phosphor volume

(2) are radiant.

Lighting device (1) according to claim 2, wherein

- on a back

(3) of the phosphor volume (2) by means of the first light beam (LI) a first

Focal spot (Bl) and by means of the second light beam (L2) a second focal spot (B2) can be generated and - One of the focal spots (Bl, B2) completely surrounds the respective other focal spot (B2, Bl).

4. lighting device (1) according to one of

preceding claims, wherein the at least one first semiconductor light source (6) at least one

Has laser diode and the at least one second

Semiconductor light source (7) has at least one light emitting diode.

5. lighting device (1) according to one of

preceding claims, wherein the first wavelength (λΐ) and the second wavelength (λ2) are blue wavelengths.

6. lighting device (1) according to one of

preceding claims, wherein a distance between the first wavelength (λΐ) and the second wavelength (λ2) is not more than 30 nanometers.

7. Lighting device (1) according to claims 5 and 6, wherein the first wavelength (λΐ) is about 435 nm and the second wavelength (λ2) is about 460 nm.

8. lighting device (1) according to one of

previous claims, wherein the second light beam with a larger opening angle on the

Fluorescent volume (2) can be irradiated as the first light beam (LI).

9. lighting device (1) according to one of

preceding claims, wherein on a front side

(10) of the phosphor volume (2) a light filter (11) is provided, which is for the light of the first wavelength

(λΐ) is at least partially reflecting and for the light of the second wavelength (λ2) and for secondary light (S) is permeable.

10. Lighting device (1) according to claim 9, wherein the light filter (11) only in a central region of a front side of the phosphor volume (2).

Abstrahlbaren Nutzlichts is present.

11. Lighting device (1) according to any one of claims 9 or 10, wherein the light filter (11) is a dichroic filter.

12. Lighting device (1) according to one of claims 9 to 11, further comprising a light filter (11) optically downstream light sensor (12), which detects only the light of the first wavelength (λΐ).

13. Lighting device (1) according to claim 12, further comprising a light sensor (12) connected to the safety circuit (13), which is adapted to at least the at least one first

Switch off semiconductor light source (6), if the light sensor (12) detects a light signal above a predetermined threshold.

14. Lighting device (1) according to one of

previous claims, wherein the

Lighting device (1) is a headlamp (H) or part of a headlamp (H).