DE102010062463A1 - Lighting-device i.e. vehicle headlight, has phosphor regions individually illuminatable by respective light sources, and aligned for diffuse radiation of light on downstream optical elements, which exhibit different optical properties - Google Patents

Abstract

The lighting-device (1) has two phosphor regions (3a, 3b) that are individually illuminatable by respective light sources, where the light sources are designed as narrow beam light sources i.e. blue lasers (2a, 2b). The lasers are designed as solid state lasers or laser diodes. The phosphor regions are aligned for partially converting wavelength of incident light, and for diffuse radiation of the light on downstream optical elements i.e. reflectors (5a, 5b), where the optical elements exhibit different optical properties. The phosphor regions are mounted on a cooling body (6).

Description

The invention relates to a lighting device having at least one light source and at least two phosphor regions which can be illuminated by the at least one light source, the phosphor regions being configured to at least partially wavelength-convert incident light from the at least one light source and to radiate it to a downstream optical element.

WO 2009/112961 A1 describes a laser light source having at least one laser light-emitting element, at least one light source output element (which is adapted to direct the laser light to a predetermined location) and at least one conversion element. The at least one conversion element comprises a set of wavelength conversion regions configured to convert the laser light to wavelength converted light so that a combination of the converted light and the laser light produces a desired output mixing light.

It is the object of the present invention to provide a particularly flexible fluorescent-based lighting device.

This object is achieved according to the features of the independent claims. Preferred embodiments are in particular the dependent claims.

The object is achieved by a lighting device having at least one light source and at least two illuminant regions that can be illuminated by the at least one light source, wherein the phosphor regions are configured to at least partially wavelength-convert incident light from the at least one light source and to radiate to at least one downstream optical element wherein the phosphor regions can be individually illuminated by the at least one light source.

Since the phosphor region can be shaped in many different forms and occupies only a small height, it can be used as a (flexibly) positionable (secondary) emitter region, in particular also at locations where an electrically operated (primary) light source (eg a laser or a light emitting diode) can not be positioned. For example, an improved reflector lighting can be achieved. In addition, a broad illumination of the at least one reflector can now be achieved in a simple manner, in particular without the aid of optical elements, for example for generating a comparatively brightness-homogeneous light distribution. By means of the individual applicability, an adjustability of the light emission pattern is additionally made possible by an additive and / or alternative activation of the phosphor regions.

The individual applicability may include an individual applicability of individual phosphor regions and / or an individual groupwise irradiability of a plurality of phosphor regions. As an option, all phosphor areas can be illuminated simultaneously.

The fact that the phosphor region or its phosphor is able to at least partially wavelength-convert light emitted by the light source may in particular mean that a part of the light irradiated by the light source onto the phosphor region is absorbed by at least one phosphor of the phosphor region and modified, in particular larger ("down-converting") or smaller ("up-converting") wavelength is re-emitted (eg from blue to yellow). Another portion of the light may be radiated back from the phosphor area without conversion of the wavelength. Thus, a monochromatic light irradiated from the associated light source can be radiated from the phosphor region as mixed light (as a combination of the wavelength converted portion and the non-wavelength converted portion), e.g. B. as a white (blue / yellow) mixed light. A phosphor region can be so selectively adjustable in terms of its thickness and / or a concentration of the at least one phosphor that consequently a wavelength-converted component is also selectively adjustable. In particular, due to a sufficiently high phosphor concentration and / or a sufficiently large thickness, the incident light can be converted substantially completely into wavelengths. This may in particular correspond to a degree of conversion of at least about 95%, in particular of at least about 98%, in particular of at least about 99%.

The wavelength conversion can be carried out, for example, on the basis of luminescence, in particular photo-luminescence or radio-luminescence, in particular phosphorescence and / or fluorescence.

In particular, the phosphor regions can emit light diffusely, which enables high intensity homogeneity and broad irradiation of the downstream optical element.

The phosphor regions can each be arranged on a flat or a curved surface (in particular a substrate with a cooling effect).

Also, a plurality of lasers, in particular laser diodes, illuminate the same area of the phosphor and / or a laser beam can with a primary optics, z. B. a primary lens, be expanded to illuminate the phosphor homogeneously.

It is an embodiment that the light source is a narrow beam light source. A narrow-beam light source may in particular be understood to mean a light source in which an opening angle of an emitted light beam is not greater than 5 °, in particular not greater than 2 °.

It is a development that the light source emits light with a low bandwidth, in particular monochromatic light. Thus, the light emitted by the at least one light source can be effectively tuned to the phosphor. The light source may in particular be a narrow-band light source, alternatively z. B. equipped with an optical band filter broadband light source.

It is a further embodiment that the light source is a laser light source. The laser light source has the advantages that it emits narrow-band light with a narrow beam angle ("narrow beam") and can also be compact and inexpensive. It is a development that the laser light source is a laser diode. This can be made particularly compact and robust. Also, laser diodes can be easily operated in groups together, eg. B. as a stack ("laser stack").

It is further an embodiment that the lighting device has at least two different (differently shaped and / or differently arranged with respect to at least one phosphor region) downstream optical elements, wherein the optical elements have different optical properties. Thus, the light beams generated by the individually illuminable phosphor regions can also be individually shaped or guided so that particularly versatile light patterns can be achieved. For example, in the case of a vehicle headlight by means of a phosphor region or a group of phosphor regions, a low beam may be generated that is relatively wide (horizontally) and has a sharp light / dark boundary in the light distribution while using another phosphor region or another group of phosphor areas an additional light beam is added to produce a high beam whose light distribution is horizontally and vertically limited, but has no light / dark boundary.

However, other lighting functions are possible, for. B. daytime running lights, static cornering light, fog light, signal light functions. Also, the lighting device may be used as a tail lamp, etc.

Alternatively, the lighting device can have an (in particular directly) downstream optical element, in particular a reflector, which can be irradiated by the phosphor regions at at least partially different and differently shaped regions.

The at least two different downstream optical elements can in particular be illuminable by different phosphor areas.

The downstream optical elements may in particular comprise at least one reflector.

It is still an embodiment that at least two phosphor areas are designed differently. This further increases a flexible designability of the light distribution pattern that can be generated by the lighting device and, consequently, a flexible usability of the lighting device. The different embodiment may include, for example, a surface, a degree of conversion (and thus a color of the mixed light, eg, by a different concentration and / or thickness of the phosphor regions), a type and number of phosphors, etc. of the phosphor regions.

In general, the type of the light sources may be the same or different (eg, a wavelength of a radiated light, a light output, etc.).

It is also an embodiment that through the different downstream optical elements feasible light has different lighting functions, z. Low beam and high beam in the case of a vehicle headlamp, yellow near-field illumination and white far-field illumination in lanterns or IR lighting, and visible light in the field of building or installation protection.

It is generally an embodiment that the lighting device is a vehicle lighting device, in particular headlights, or serves as such. The vehicle lighting device can then also be particularly compact and with regard to its different light distributions (eg dipped beam, high beam, etc.) design-wise flexible in terms of design. This makes it possible to meet the existing stringent requirements for precise beam guidance for vehicle lighting devices, in particular Spotlight, particularly effective to meet or even surpass.

It is still an embodiment that the lighting device has at least two sets each of a light source and a phosphor region, which are individually activated and deactivated. As a result, a particularly easily controllable and flexible and / or spatially complete illumination of the at least one downstream optical element is made possible. In addition, the brightness can be increased.

It is a development that the sentences produce a substantially uniform light distribution pattern. The uniform light distribution pattern may be angularly offset in particular about a longitudinal axis or optical axis of the lighting device, for. B. by 180 ° at two sets or by 120 ° at three sets, etc.

However, the sets can also produce a significantly different light distribution pattern relative to each other. As a result, for example by means of one or more of the sentences in an automobile headlight o. Ä. A dipped beam can be generated and, for example, by an additional activation of at least one additional set a high beam are generated.

It is also an embodiment that the at least one phosphor region can be directly irradiated by means of at least one light source. So intensity losses can be reduced.

It is also an embodiment that the at least one phosphor region can be illuminated by means of at least one light source via at least one reflector. Thereby, first, a position of the at least one light source can be decoupled from a position of the at least one phosphor region, and consequently both elements can be arranged more versatile. Secondly, a beam widening can be achieved in a simple manner, and consequently the phosphor region can be exposed over a particularly large area. For this purpose, the reflector can in particular have at least one locally limited, dedicated reflector region, which is set up and designed to direct the light emitted by the at least one light source to the phosphor region.

Generally, at least one beam-expanding optical element may be present between the light source and the associated phosphor region.

It is also an embodiment that the at least one phosphor region is arranged in or near a focal point of the at least one downstream optical element, in particular reflector.

It is yet another embodiment that the at least one phosphor region is attached to a heat sink. Thus, heating of the at least one phosphor region due to Stokes losses and a consequent life reduction and also possible wavelength shift of the re-emitted light can be substantially prevented.

It is yet an embodiment that the at least one phosphor region is arranged on a projection, wherein the projection projects into a reflector cavity formed by at least one reflector as the downstream optical element. Thus, the at least one reflector can be irradiated over a large area by means of the at least one phosphor region. Also, so the at least one phosphor region can be particularly easily positioned with respect to the reflector, z. B. at or near a focal point o. Ä.

It is also an embodiment that the projection protrudes from a rear end of the lighting device in the reflector cavity. This allows for easy installation.

It is still an embodiment that the at least one light source is arranged on the projection. Thus, the light source can be aligned in many directions, and the at least one phosphor region can be positioned accordingly diverse.

It is yet a further embodiment that the at least one light source is arranged on a base from which the projection protrudes substantially perpendicularly. Thus, the at least one light source can illuminate a arranged on the projection at least one phosphor area with a compact design directly.

In the following figures, the invention will be described schematically with reference to exemplary embodiments. In this case, the same or equivalent elements may be provided with the same reference numerals for clarity.

1 shows a section in side view of a section of a lighting device according to a first embodiment; and

2 shows a sectional view in side view of a section of a lighting device according to a second embodiment.

1 shows a sectional view in side view components of a lighting device 1 according to a first embodiment.

The lighting device 1 has around its axis of symmetry or longitudinal axis S rotationally symmetrically arranged around at least two blue laser 2a . 2 B of which two with respect to the longitudinal axis L mirror-symmetrically arranged laser 2a . 2 B are shown. The lasers 2a . 2 B are designed as solid state lasers ("solid state lasers") or laser diodes and emit blue primary light L1, z. B. in a wavelength range of 350 nm to 460 nm, in particular of about 405 nm, directly to a respective phosphor region 3a . 3b ,

Each of the phosphor areas 3a . 3b has a phosphor which is that of the laser 2 radiated blue primary light L1 with an adjustable degree of conversion U into yellow secondary light L2 converts. A portion U of the incident primary light L1 is detected by means of the phosphor region 3 thus converted into secondary light L2, and a substantially complementary portion (1-U) is not wavelength converted, so remains blue primary light L1. That of the phosphor areas 3 radiated light is thus a mixed light L1, L2 with a proportion U of the blue primary light L1 and (1-U) of the yellow secondary light L2, z. B. white light. In this case, U can basically be in a range [0, ..., 1]. The proportion U can be the same for the two phosphor areas (and the two phosphor areas thus emit a mixed color L1, L2 of the same color), or the proportions U and thus mixed colors can be different.

From the respective phosphor area 3a . 3b the light L1, L2 becomes diffuse on an inside 4a . 4b a respective downstream optical element in the form of a reflector 5a . 5b radiated. The insides 4a . 4b are here each shell-shaped, z. B. parabolic or as freeform surfaces, z. B. multiple faceted. The reflectors 5a . 5b or their insides 4a . 4b reflect that from the associated phosphor area 3a respectively. 3b incident light L1, L2 one or more times in the direction of a common light exit plane E of the reflectors 5a . 5b , The reflectors 5a . 5b are designed differently (eg with a different contour of the insides 4a respectively. 4b and / or differently oriented), so that of the respective phosphor areas 3a . 3b radiated light L1, L2 is not symmetrical to the longitudinal axis S. The phosphor areas 3a and 3b may in particular in or near a focal point of the respective associated reflector 5a respectively. 5b are located.

The light exit plane E of the reflector 5 is here by the free edge of the reflectors 4a . 4b clamped. The light exit plane E may represent an intermediate level, the image of which by means of at least one downstream optics (not shown), in particular imaging optics, z. B. lens, is shown further. That of the respective laser 2a . 2 B emitted narrow beam and intense light beam L1 falls directly on the phosphor area 3a respectively. 3b and is greatly expanded there, so that at the light exit plane E a large-scale and bright brightness homogeneous image for the respective phosphor area 3a respectively. 3b results. Alternatively, optics downstream of the light exit plane E can also be dispensed with.

The phosphor areas 3a . 3b are on a common heat sink 6 arranged to dissipate the heat generated by Stokes losses due to the wavelength conversion. The heat sink 6 is here as a metallic, about the longitudinal axis S rotationally symmetrical body formed, which has an open back of the one through the reflectors 5a . 5b formed body closes and centrally a cylindrical projection 7 having. The lead 7 extends from one the open back of the reflectors 5a . 5b occlusive base area 8th along the longitudinal axis S in one through the reflectors 5a . 5b formed reflector interior or reflector cavity 9 in the direction of the light exit level E.

The phosphor areas 3a . 3b are on a lateral surface 10 of the projection 7 arranged, at or near the free end surface 11 , The phosphor areas 3a . 3b may be separate areas or on a common, annular around the outer surface 10 be formed encircling fluorescent ring. This positioning allows the phosphor areas 3a . 3b the insides 4a . 4b of the respective reflector 5a . 5b irradiate large areas, which may favor, for example, a homogeneous distribution of brightness.

The lasers 2a . 2 B are on the other hand with the base area 8th connected or shine through it. The lasers 2a . 2 B are aligned obliquely with respect to the longitudinal axis S to a compact design of the lighting device with direct illumination of the phosphor areas 3a . 3b to enable.

To avoid light loss, the heat sink can 6 be designed reflective.

The pictures of the phosphor areas 3a respectively. 3b can z. B. differ in their position, color, shape and / or brightness. This makes it possible, by an individual activation or illumination of the phosphor areas 3a and 3b produce different light patterns, which can differ significantly. For example, the lighting device 1 at least part of one Vehicle headlights represent. By activating the phosphor area 3a can z. B. a low beam function can be activated by an additional activation of the phosphor region 3b can z. B. a high beam function can be activated.

2 shows a sectional view in side view components of a lighting device 12 according to a second embodiment. The lighting device 12 is shown here in a section of the upper half with respect to the longitudinal axis S.

In contrast to the lighting device 1 The first embodiment is the laser 2a now at the projection 7 of the heat sink 6 attached and radiates, z. B. blue, primary light L1 to a dedicated reflector area 13a on an inside 14a a reflector 15a , The dedicated reflector area 13a is specific to the reflection of the laser 2a radiated primary light L1 on the associated phosphor area 3a designed. The dedicated reflector area 13a surrounding inside 14a of the reflector 15a is not optimized for a reflection of the primary light L1. The reflector area 13a can against the surrounding inside 14a z. B. be angled or have an edge with it.

The phosphor area 3a also shines here, z. B. blue-yellow or white, mixed light L1, L2 substantially to the reflector 15a or its inside 14a , where the reflector 15a the mixed light L1, L2 further reflected in the direction of the light exit plane E. Again, the light exit plane, for example, an imaging optics (o. Fig.) To be followed.

This lighting device 12 has, among other things, the advantage that a base range 8th can be small or even it can be dispensed with. The lead 7 can z. B. be hollow, z through the inner cavity. B. lines to the laser 2a can be performed.

The mirrored on the longitudinal axis S half (in 1 provided with the suffix "b") can basically be constructed similarly, for example, z. B. analogous to 1 , Shape and position of the reflector, the dedicated reflector region, the phosphor region, etc. may be configured differently.

Of course, the present invention is not limited to the embodiments shown.

Features of the various embodiments may be used additively and / or replaced. For example, the heat sink of the second embodiment may be metallic and / or reflective on its outside for a higher light output.

Also, the phosphor regions may generally include a plurality of phosphors having different wavelength conversion characteristics, for example for converting primary light into secondary light of different wavelengths.

Furthermore, primary light having a plurality of significantly different wavelengths can be irradiated onto the phosphor regions.

In general, any wavelength conversions can be made, in particular from shorter to longer wavelengths (down-converting), z. B. of UV light in red, green and blue light. The phosphor area can then z. B. corresponding to three different phosphors, z. B. for the conversions UV in red, UV in green and UV in blue. Also, IR light can be generated.

In general, the phosphors are preferably luminescence-based phosphors.

In general, the phosphor ranges may differ in their nature (degree of conversion, concentration and / or thickness of the phosphor, irradiated area, composition of the phosphor, number of phosphors, etc.), so that differently activated phosphor regions e.g. B. also different colored and / or different bright light can emit, etc. The wavelength conversion or conversion can basically z. B. on the in WO 2009/112961 A1 described types happen.

In general, the number of differently activatable phosphor regions can also be different.

Furthermore, instead of the dedicated reflector region of the second embodiment, for example, a semitransparent mirror may also be incorporated in the reflector, by means of which primary light can be radiated onto the associated phosphor region from the outside. Thus, the light source can be placed outside the reflector, resulting in a greater variety of usable light sources.

In addition, instead of the different reflectors, it is also possible to use a single, in particular circulating, reflector, which provides or has at least partially differently shaped reflector regions for the light beams generated by the different phosphor regions.

The at least one phosphor region may generally be in a light-transmitting arrangement or in a light-reflecting arrangement.

In general, white light can be generated by the combination of laser (s) and phosphor region (s). In this case, a white light of different color temperature can also be generated by different laser (s) and phosphor area (s). Thus, in particular for applications in vehicle headlights for different lighting functions different white light can be used.

Generally, different combinations of laser (s) and phosphor region (s) can produce differently colored light or mixed light.

It may be another general design that the phosphor region converts incident light directly into white light.

The phosphor regions can generally be applied to a common or separate heat sinks.

Neither the luminous areas nor the lasers nor the reflectors need to be symmetrically arranged and / or configured and are in particular not limited to a rotationally symmetrical or mirror-symmetrical arrangement.

LIST OF REFERENCE NUMBERS

1

lighting device

2a

laser

2 B

laser

3a

Phosphor region

3b

Phosphor region

4a

Inside of the reflector

4b

Inside of the reflector

5a

reflector

5b

reflector

6

heatsink

7

head Start

8th

base region

9

Reflektorkavität

10

Lateral surface of the projection

11

End face of the projection

12

lighting device

13a

dedicated reflector area

14a

Inside of the reflector

15a

reflector

e

Light exit plane

L1

primary light

L2

secondary light

S

longitudinal axis

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2009/112961 A1 [0002, 0061]

Claims (15)

Lighting device ( 1 ; 12 ), comprising at least one light source ( 2a . 2 B ) and at least two of the at least one light source ( 2a . 2 B ) illuminable phosphor areas ( 3a . 3b ), wherein the phosphor areas ( 3a . 3b ) are adapted from the at least one light source ( 2a . 2 B ) at least partially wavelength-converting incident light and, in particular diffusely, to at least one downstream optical element, in particular a reflector ( 5a . 5b ; 15a ), and wherein the phosphor areas ( 3a . 3b ) from the at least one light source ( 2a . 2 B ) are individually illuminatable. Lighting device ( 1 ; 12 ) according to claim 1, wherein the light source is a narrow-beam light source, in particular a laser light source ( 2a . 2 B ) is. Lighting device ( 1 ; 12 ) according to one of the preceding claims, wherein the lighting device ( 1 ; 12 ) at least two different downstream optical elements ( 5a . 5b ; 15a ), wherein the optical elements ( 5a . 5b ; 15a ) have different optical properties and of different phosphor areas ( 3a . 3b ) are illuminatable. Lighting device ( 1 ; 12 ) according to any one of the preceding claims, wherein at least two phosphor areas ( 3a . 3b ) are designed differently. Lighting device ( 1 ; 12 ) according to one of claims 3 and 4, wherein the different downstream optical elements ( 5a . 5b ) light (L1, L2) has different lighting functions. Lighting device ( 1 ; 12 ) according to one of the preceding claims, wherein the lighting device ( 1 ) is a vehicle light device, in particular headlights, is. Lighting device ( 1 ; 12 ) according to one of the preceding claims, wherein the lighting device ( 1 ) at least two sets of one light source each ( 2a . 2 B ) and a phosphor region ( 3a . 3b ), which are individually activated and deactivated. Lighting device ( 1 ) according to any one of the preceding claims, wherein the at least one phosphor region ( 3a . 3b ) by means of at least one light source ( 2a . 2 B ) is directly illuminatable. Lighting device ( 12 ) according to any one of the preceding claims, wherein the at least one phosphor region ( 3a ) by means of at least one light source ( 2a ) via at least one reflector ( 15a ) is illuminable. Lighting device ( 1 ; 12 ) according to any one of the preceding claims, wherein the at least one phosphor region ( 3a . 3b ) in or near a focal point of the at least one downstream optical element ( 5a . 5b ; 15a ) is arranged. Lighting device ( 1 ; 12 ) according to any one of the preceding claims, wherein the at least one phosphor region ( 3a . 3b ) on a heat sink ( 6 ) is attached. Lighting device ( 1 ; 12 ) according to any one of the preceding claims, wherein the at least one phosphor region ( 3a . 3b ) at a projection ( 7 ), wherein the projection ( 7 ) in a through at least one reflector ( 5a . 5b ; 15a ) formed reflector cavity ( 9 protrudes. Lighting device ( 1 ; 12 ) according to claim 12, wherein the projection ( 7 ) from a rear end of the lighting device ( 1 ; 12 ) out into the reflector cavity ( 9 protrudes. Lighting device ( 1 ; 12 ) according to one of claims 12 or 13, wherein the at least one light source ( 2a . 2 B ) on the projection ( 7 ) is arranged. Lighting device ( 1 ; 12 ) according to one of claims 12 or 13, wherein the at least one light source ( 2a . 2 B ) at a base ( 8th ) is arranged, from which the projection ( 7 ) protrudes substantially perpendicularly.

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