DE102011082808A1 - Lighting device with semiconductor light source and phosphor area - Google Patents

Abstract

The lighting device (11) has at least one support surface (12) on which there is at least one semiconductor light source (18-20) and at least one phosphor region (13-15), the at least one phosphor region (13-15) being formed by at least one semiconductor light source ( 18) can be irradiated.

Description

The invention relates to a lighting device on which at least one semiconductor light source and at least one phosphor region are present, wherein the at least one phosphor region can be irradiated by the at least one semiconductor light source. The lighting device is particularly suitable for the simultaneous display of information and general lighting.

US 2008/0144333 A1 relates to a light guiding device and a manufacturing method comprising a substrate on which a number of luminous regions and a number of optical fibers are printed, wherein the optical fibers are optically coupled to the luminous regions. With this arrangement, light injected at one end of the light guide is transmitted to the light areas where it can then exit the device. Control of the light transmitted to the luminous areas can provide a light source with color changeover and switching capabilities that are both flexible and suitable for use in a variety of static and dynamic display applications.

US 5,757,348 relates to a system and method for generating spatially modulated monochrome or colored light with gray levels for a predetermined period of time, comprising a spatial light modulator having a light modulation arrangement that is switchable between different states to act differently on light. A switching arrangement switches the modulation arrangement between different states in a controlled manner during the period of time. The system also includes a lighting arrangement for selectively and alternately directing light of constant intensity and varying intensity into the modulation arrangement during predetermined part time periods of the time period. In a color version of the system, the illumination assembly directs light of different colors into the modulation array during predetermined part time periods of the time period, thereby providing a system for generating color light levels of modulated color light during a predetermined period of time. In one embodiment, the predetermined part-time spans comprise a first plurality of part-time spans of unequal length of time which, when arranged in chronological order, increase in duration by a factor of two. The predetermined part-time periods further include a second plurality of part-time periods, and the illumination arrangement directs light of different intensities into the modulator arrangement during each of the second plurality of part-time periods, which are of equal duration. Each of the different intensities of the light doubles from part-time to part-time when the part-time spans of equal length are arranged in a particular order.

US 5,748,164 relates to a system for generating spatially modulated grayscale monochrome or colored light comprising an active matrix liquid crystal spatial light modulator comprising light modulation means comprising (i) a layer of ferroelectric liquid crystal material adapted to be between AN and And (ii) an active matrix means comprising a VLSI circuit for separating the layer of liquid crystal material into an array of individual liquid crystal pixels and causing each of the pixels of liquid crystal material to individually modulate light, by switching between the ON and OFF states in a manner dependent on the data being written to the VLSI circuit. The system also includes illumination means having a light source for directing light from the source into the pixelized layer of ferroelectric liquid crystal material in a particular manner. Finally, the system includes means for writing the VLSI circuit with preselected data in accordance with a particular data ordering scheme, such that the circuit in response to the written data causes the pixels of the liquid crystal material to individually switch between their ON and OFF states, and thus light from the source in a manner which, depending on the data, produces a particular overall pattern of gray-scale light.

US 7,595,588 B2 relates to a method of producing an electroluminescent device in which a plurality of organic electroluminescent pixels are formed on a transparent substrate, an active electronic circuit is formed on a second separate substrate, and the two substrates are assembled, the active electronic circuit being in such a way on the transparent substrate shows that discrete electrical connections between the active electronic circuit and the organic light-emitting diode pixels are formed. An insulating matrix material can then be used to fill the space between the substrates.

US 7,601,942 B2 relates to an optoelectronic device comprising a substrate comprising a semiconductive material and an array of smart pixels disposed on or in the substrate, each smart pixel in contact with at least one layer of organic phosphor material and a light transmissive electrode the organic layer on one side of it remote from the substrate. The smart pixels may be capable of one or a variety of functions, including image capture, processing, communication, and display.

It is the object of the present invention to provide an improved lighting device of the type described above.

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, comprising at least one support surface, on which at least one semiconductor light source and at least one phosphor region are present, wherein the at least one phosphor region can be irradiated by at least one semiconductor light source.

The at least one semiconductor light source and the at least one phosphor region are therefore arranged or mounted in particular on the same or common support surface and, for example, not on opposite, separate bearing surfaces.

A phosphor region may, in particular, be understood as meaning a region of the support surface which is covered with one or more wavelength-converting phosphors. A phosphor is understood in particular as meaning a substance which is capable of converting at least partially light incident on it of a (first) primary wavelength into light of a (second) secondary wavelength ("wavelength conversion"). The secondary wavelength is usually greater than the primary wavelength ("down conversion"). In particular, the primary wavelength may correspond to UV or visible light (e.g., blue light). In particular, the secondary wavelength may correspond to visible light (e.g., blue, red, or green light) or infrared light.

Preferably, the at least one semiconductor light source comprises at least one light-emitting diode. If several LEDs are present, they can be lit in the same color or in different colors. A color may be monochrome (e.g., red, green, blue, etc.) or multichrome (e.g., white). The light emitted by the at least one light-emitting diode can also be an infrared light (IR LED) or an ultraviolet light (UV LED). Several light emitting diodes can produce a mixed light; e.g. a white mixed light. The at least one light-emitting diode may contain at least one wavelength-converting phosphor (conversion LED). The at least one light-emitting diode can be in the form of at least one individually housed light-emitting diode or in the form of at least one LED chip. Several LED chips can be mounted on a common substrate ("submount"). The at least one light emitting diode may be equipped with at least one own and / or common optics for beam guidance, e.g. at least one Fresnel lens, collimator, and so on. Instead of or in addition to inorganic light emitting diodes, e.g. based on InGaN or AlInGaP, organic LEDs (OLEDs, for example polymer OLEDs) can generally also be used. Alternatively, the at least one semiconductor light source may be e.g. have at least one diode laser.

This lighting device has the advantage that it allows a large area and very thin structure (low height). This in turn allows a very light emitting device, which has a low material consumption. In addition, so information can be displayed while maintaining a lighting function.

It is in principle possible, for example, to use semiconductor light sources which can be emitted upward (for example so-called top LEDs) whose main emission direction is parallel to a surface normal of the support surface and which therefore emit their light perpendicular to the support surface. In order to direct the light of these semiconductor light sources which can be emitted upward onto at least one phosphor area (which can not be directly illuminated here), a semiconductor light source which can be emitted upward can be equipped with a retroreflective optic, or the semiconductor light source can comprise at least one optical element, e.g. a reflective, in particular totally reflecting, layer, downstream, which deflects the light of the semiconductor light source at least partially on at least one phosphor region.

The lighting device may have one or more contact surfaces, which adjoin one another and / or are spaced apart from one another.

It is an embodiment that the at least one semiconductor source comprises at least one laterally emitting semiconductor light source. A laterally emitting semiconductor light source can be understood in particular to mean a semiconductor light source whose main emission direction is oblique to a surface normal of the support surface, in particular perpendicular thereto and thus parallel to the surface of the support surface (for example in the case of a so-called "side LED"). This makes it possible to direct at least a portion of the emitted light from the side emitting semiconductor light source directly to at least one phosphor region, which simplifies a structure of the lighting device and increases a light output.

It is still an embodiment that are arranged on the support surface semiconductor light sources with different Lichtabstrahlrichtungen. Thus, the lighting device can produce particularly diverse light patterns or images. For example, both laterally emitting semiconductor light sources and upwardly emitting semiconductor light sources can be arranged on the support surface.

It is a further development that light from at least one of the semiconductor light sources is emitted directly (i.e., without striking a phosphor region to any significant extent) from the light emitting device, in particular from an upwardly radiating semiconductor light source. Such a semiconductor light source is therefore not associated with a phosphor region and may in particular comprise at least one upwardly emitting and / or at least one laterally emitting semiconductor light source.

It is a further embodiment that the at least one phosphor region comprises a plurality of phosphor regions and each phosphor region is assigned a semiconductor light source. As a result, an effective illumination of the phosphor areas and thus a high-grade wavelength conversion can be ensured. In addition, an individual illumination of phosphor areas and consequently a variable light emission from the lighting device is thus made possible.

The fact that each phosphor region is assigned a semiconductor light source can mean, in particular, that at least one phosphor region is assigned to at least one phosphor region, ie at least one phosphor region can be irradiated by a plurality of semiconductor light sources, in particular by semiconductor light sources of different primary wavelengths, in particular if Phosphor region comprises a plurality of phosphors) and / or that a plurality of phosphor regions is assigned a same semiconductor light source.

It is yet another embodiment that the at least one semiconductor light source and the at least one phosphor region are covered by a transparent layer, in particular a silicone layer. Firstly, a protection of the at least one semiconductor light source and of the at least one phosphor region is provided, and secondly, a part of the light emitted by the at least one semiconductor light source may not reflect directly on a phosphor region by reflection, in particular internal total reflection (TIR), on a surface the transparent layer to be reflected on a phosphor region, which further increases a luminous efficacy. The total internal reflection can be exploited in particular by a laterally emitting semiconductor light source.

The transparent layer may in particular comprise or be a potting material, so that the at least one semiconductor light source and the at least one phosphor region are potted by the transparent layer.

The use of silicone as the material of the transparent layer has the advantage that silicone is resistant, can be used as a potting material and is also elastically deformable, so that a deformation of the support surface of the silicone thereon can be mitmachen.

It is also an embodiment that the transparent layer is covered by a transparent glass layer. The glass layer (e.g., in the form of a thin glass plate in the present case) provides a particularly high resistance to mechanical and chemical stresses. In addition, the glass layer allows a particularly effective reflection of obliquely emitted light components of the semiconductor light sources, in particular laterally emitting semiconductor light sources.

As an alternative to the glass layer, however, any other transparent layer may also be used, e.g. a plastic layer.

In particular, the transparent layer can also be used as a filter for certain spectral components of light, for example for primary light. This is particularly advantageous if only wavelength-converted secondary light is to emerge from the lighting device. For example, the at least one semiconductor light source may be a UV light source, and the phosphor regions may like the UV primary light emitted therefrom in e.g. convert red, green or blue secondary light. To prevent UV light from leaking out of the light device, the transparent layer may serve as a UV filter for the UV primary light.

It is also an embodiment that the at least one phosphor region comprises a plurality of phosphor regions, which are distributed in a regular pattern on the support surface. This makes it possible to generate a picture-like image by the lighting device. In particular, for this purpose, the phosphor regions can at least partially have different phosphors and consequently emit secondary light of different wavelengths.

However, the phosphor areas may also be irregularly distributed on the support surface.

A logical pixel of the lighting device can be formed by a local group or cluster of several phosphor areas with different phosphors, for example by closely adjacent phosphor areas which emit secondary light of the colors red, green or blue or can also emit further colors, eg amber ("amber"). ). A color or a color impression of the mixed light generated by the phosphor regions of a pixel can be varied by an individually assigned semiconductor light source, for example by means of an adjustment of the beam intensities of the semiconductor light sources in the case of individual irradiation of the phosphor regions.

In order to be able to set different proportions of the spectrum of the mixed light generated by a pixel (eg in order to achieve a proportion of about 5: 3: 1 for red, green or blue light for color mixing to white light), the number of phosphor regions, Size of the phosphor regions and / or density of the phosphor of the phosphor regions can be adjusted specifically.

Alternatively, a logical pixel may be formed by a phosphor region with a phosphor or, in particular, with a plurality of phosphors, the plurality of phosphors producing a multichromic mixed light. Such a development can be arranged particularly tight, resulting in a high image resolution.

The shape of the phosphor areas is not limited. However, a regular basic shape is preferred to allow at least approximately uniform resolution in all directions. In particular, the phosphor regions may be formed circular, square, hexagonal or octagonal. In particular, the square, hexagonal or octagonal basic shape allows a high surface coverage. However, the shape of the phosphor regions is not limited (especially not to a dot-like basic shape) and may be e.g. also has a linear or free-form basic shape.

It is also an embodiment that the support surface is a surface of a heat sink. This enables effective heat removal of the waste heat of the at least one semiconductor light source and the Stokes heat of the at least one phosphor region, even if the at least one semiconductor light source and the at least one phosphor region are covered by a layer.

It is yet another embodiment that the support surface is a surface of a plastically deformable plate. Thus, the light-emitting surface of the lighting device can be shaped manifold, even in a final assembly. Furthermore, the support surface can thus also be deformed after application of the at least one semiconductor light source and the at least one phosphor region.

The plate-shaped lighting device can be equipped on one or both sides with semiconductor light sources. Each of the sides of the plate can therefore basically serve as a support surface.

It is a development that the plate is an aluminum plate. This has the advantages that it has a very high thermal conductivity, easily deformable and is also inexpensive. However, in particular other materials with a good thermal conductivity (λ> about 15 W / (m K)) can be used, in particular metals, e.g. Copper.

In principle, any shaped support surfaces are usable, e.g. annular or annular sector shaped bearing surfaces.

The plate may in particular be formed as a sheet, in particular as a sheet with a thickness of less than 3 mm, in particular as a sheet with a thickness of 100 micrometers or less. The sheet allows a particularly simple deformability and a very low weight and a particularly low material consumption.

In particular, the plate can be fitted on one side and can be adhesively attached or otherwise fastened to a support on its other side, in particular to a support in the form of a heat sink, in particular flat, for example via a thermal interface material (TIM) such as a heat conducting foil or a thermal grease.

It is still an embodiment that all semiconductor light sources emit light of the same color. As a result, a background light of the same color is generated via the light-radiating surface of the lighting device, which supports a similar color impression over the surface.

On the support surface and electrical lines, in particular conductor tracks, to supply the semiconductor light source (s) may be present. Also, electronic components may be present on the support surface, in particular for driving the semiconductor light source (s).

It is yet another embodiment that mixes the light of the lighting device in a far field to a mixed light of substantially the same color. This allows the lighting device in the far field for general lighting means be used of the mixed light and represent information when viewed at a closer proximity. Consequently, the lighting device can be used simultaneously for general lighting and information transmission.

The setting of when the far field starts (far field boundary) may be dependent on a selected application. In particular, the far field boundary may be at least about 30 cm, in particular at least about 50 cm and in particular at least about 1 meter. The farther the far field boundary is, the coarser or sharper the resolution of an image can be selected.

It is a further development that the mixed light perceived in the far field (essentially color uniformly) has a sum color location on or near the Planck curve.

It is still a development that the light perceived in the far field is a white (e.g., warm white or cold white) light.

The above-described characteristics, features, and advantages of this invention, as well as the manner in which they will be achieved, will become clearer and more clearly understood in connection with the following schematic description of exemplary embodiments which will be described in detail in conjunction with the drawings. In this case, the same or equivalent elements may be provided with the same reference numerals for clarity.

1 shows in plan view of a support surface of a lighting device according to a first embodiment with phosphor areas mounted thereon;

2 shows the arrangement 1 with an additional electrical supply line;

3 shows the arrangement 2 additionally with the phosphor areas illuminating semiconductor light sources;

4 shows the arrangement 3 in addition to other semiconductor light sources;

5 shows a sectional view in side view of a section of the in 4 shown arrangement;

6 shows a sectional side view of the finished lighting device according to the first embodiment as an arrangement 5 with an additionally transparent potting layer;

7 shows a lighting device according to the first embodiment in operation;

8th shows a sectional side view of a lighting device according to a second embodiment; and

9 shows in plan view a lighting device according to a third embodiment.

1 shows in plan view a support surface 12 a lighting device 11 according to a first embodiment with phosphor areas attached thereto 13 . 14 . 15 , The bearing surface 12 is shown here, but can also be curved, for example.

The bearing surface 12 is by means of one side of serving as a heat sink or heat spreader aluminum plate 16 educated. The aluminum plate 16 is so thin that it can be plastically deformed manually or with only a minor use of tools. The phosphor areas 13 . 14 and 15 each have a different phosphor and each emit light of a different spectrum, in particular another secondary wavelength. The phosphor areas 13 . 14 and 15 emit here purely by way of example blue light, green light or red light.

The phosphor areas 13 to 15 can basically be placed anywhere on the support surface 12 be arranged, for example, in a first group G1 of rectilinearly arranged in series phosphor areas 13 to 15 in a second group G2 of matrix-like phosphor regions 13 to 15 and / or in a third group G3 of curved phosphor regions arranged in series 13 to 15 ,

2 shows the arrangement 13 to 16 out 1 with an additional electrical supply line 17 , The electrical supply line 17 may in particular be formed as a metallic conductor, which for electrical insulation against the aluminum plate 16 can be applied to an electrically insulating insulating layer (o.Fig.).

The supply line 17 runs near the phosphor areas 13 to 15 and is the end electrically contacted, eg by contact fields (o.Fig.).

3 shows the arrangement 13 to 17 out 2 additionally with the phosphor areas 13 to 15 illuminating semiconductor light sources in the form of laterally emitting LEDs 18 , Whose Hauptabstrahlrichtung is indicated by the arrow and to each next adjacent Phosphor region 13 to 15 is directed. As a result, each of the phosphor areas becomes 13 to 15 at least mainly by the next adjacent, associated light-emitting diode 18 irradiated.

The phosphor areas 13 to 15 A group G1, G2 or G3 can each be controlled jointly and, given sufficient spatial proximity, produce a mixed light from the wavelength-converted light. The groups G1, G2 and / or G3 can consequently also be understood as pixels, by means of which information (an image, numbers, letters, symbols, etc.) can be transmitted at least in a near field.

4 shows the arrangement 13 to 18 out 3 additionally with further semiconductor light sources in the form of laterally emitting LEDs 19 and upward (from the image plane) emitting light emitting diodes 20 , The other LEDs 19 and 20 do not directly emit their light to any significant extent on any of the phosphor areas 13 to 15 , The light-emitting diodes 19 and 20 Rather serve to provide a more uniform color and / or brightness impression over the support surface 12 , in particular in a far field of the lighting device 11 , to create.

For a uniform color impression over the support surface 12 , in particular in a far field of the lighting device 11 , it may be advantageous that the light emitting diodes 18 to 20 Emit light of the same color or the same spectrum.

5 shows a sectional view in side view of a section of the in 4 shown arrangement in the region of there drawn section A with a side emitting light emitting diode 18 and an associated phosphor region 14 , Such a lighting device can already be used, for example by applying a suitable operating voltage to the ends of the supply line 17 which the light emitting diodes 18 eg electrically connected in series can supply power.

6 shows a sectional view in side view of the finished lighting device 11 according to the first embodiment as an arrangement 5 with an additional transparent sealing layer 21 made of silicone. The casting layer 21 serves the purpose on the support surface 12 applied elements (light-emitting diodes 18 to 20 , Phosphor areas 13 to 15 etc.), in particular against mechanical and chemical stress. The casting layer 21 still allows a deformation of the lighting device 11 after their application.

7 shows a lighting device according to the first embodiment in operation. The light-emitting diode 18 its primary light P radiates laterally into the casting layer 21 which partly depends on the phosphor area 14 meets. There, the primary light P is at least partially converted into secondary light S, isotropic in the potting layer 21 emitted and from the potting layer 21 through their free surface 22 largely discharged to the outside.

The casting layer 21 also acts for that of the light emitting diode 18 radiated, not on the light area 14 falling light like a light guide with total internal reflection. At the free surface 22 Thus, the primary light P can be reflected and put into the luminous area 14 or invade another light area and converted there into secondary light S. This increases the luminous efficacy.

8th shows a sectional view in side view of a lighting device 31 according to a second embodiment.

Here, the transparent potting layer 21 additionally of a transparent glass layer 32 covered. This further increases resistance and luminous efficacy (through enhanced reflection), especially in low light incidence.

The use of the glass layer 32 has the further advantage that it can optionally be used as a filter, for example for the primary light P and / or other spectral ranges.

The above figures may also include various method steps for producing a lighting device 11 respectively. 31 represent. The sequence shown does not need to be adhered to. So likes the at least one electrical connection line 17 for example, before or after the phosphor areas 13 to 15 (eg imprinted) or before or after the light-emitting diodes 13 to 15 be applied.

9 shows in plan view a lighting device 41 according to a third embodiment.

At the lighting device 41 are phosphor areas 13 to 15 in a geometrically regular pattern (here: in a square 12 × 8 matrix pattern) on the support surface 12 distributed and form together with the associated light-emitting diodes 18 Groups or clusters serving as pixels B1, B2. The pixels B1 and B2 emit light of different color or a different spectrum in the configuration shown and can thereby, when viewed in a near field (preferably at a distance of less than 30 cm to 1 m) transport information, such as numbers, symbols, Letters, pictures etc., here: the number '110'.

With increasing distance from the lighting device 41 However, the colors mix Pixels B1 and B2 more and more, so that the light of the pixels B1 and B2 in a far field (preferably greater than about 30 cm to 1 m) mixed to a (far-field) mixed light of substantially the same color and then for general lighting without Information reproduction is available. This mixed color of the far-field mixed light is preferably white or a whitish tone, especially in the vicinity or on the Planck curve.

Although the invention has been further illustrated and described in detail by the illustrated embodiments, the invention is not so limited and other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention.

Thus, a wavelength of the wavelength-converted light is generally not limited, especially not to the colors red, green and / or blue.

Also likes on the light emitting diodes 19 and or 20 be waived.

LIST OF REFERENCE NUMBERS

11

 lighting device

12

 bearing surface

13

 Phosphor region

14

 Phosphor region

15

 Phosphor region

16

 aluminum plate

17

 supply line

18

 laterally emitting LED

19

 laterally emitting LED

20

 upward emitting LED

21

 cast layer

22

 free surface

31

 lighting device

32

 glass layer

41

 lighting device

B1

 pixel

B2

 pixel

G1

 Group of linearly arranged in series phosphor areas

G2

 Group of matrix-like arranged phosphor areas

G3

 Group of curved luminescent phosphor regions

P

primary light

S

secondary light

A

neckline

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

• US 2008/0144333 A1 [0002]
• US 5757348 [0003]
• US 5748164 [0004]
• US 7595588 B2 [0005]
• US 7601942 B2 [0006]

Claims (11)

Lighting device ( 11 ; 31 ; 41 ), comprising at least one bearing surface ( 12 ), on which at least one semiconductor light source ( 18 - 20 ) and at least one phosphor region ( 13 - 15 ), wherein the at least one phosphor region ( 13 - 15 ) by at least one semiconductor light source ( 18 ) is irradiated. Lighting device ( 11 ; 31 ; 41 ) according to claim 1, wherein the at least one semiconductor source ( 18 - 20 ) at least one laterally emitting semiconductor light source ( 18 . 19 ). Lighting device ( 11 ; 31 ; 41 ) according to one of the preceding claims, wherein on the support surface ( 12 ) Semiconductor light sources ( 18 - 20 ) are arranged with different Lichtabstrahlrichtungen. Lighting device ( 11 ; 31 ; 41 ) according to any one of the preceding claims, wherein the at least one phosphor region ( 13 - 15 ) comprises a plurality of phosphor regions and each phosphor region ( 13 - 15 ) a semiconductor light source ( 18 ) assigned. Lighting device ( 11 ; 31 ; 41 ) according to one of the preceding claims, wherein the at least one semiconductor light source ( 18 - 20 ) and the at least one phosphor region ( 13 - 15 ) of a transparent layer ( 21 ), in particular silicone layer, are covered. Lighting device ( 31 ; 41 ) according to claim 5, wherein the transparent layer ( 21 ) of a transparent glass layer ( 32 ) is covered. Lighting device ( 41 ) according to any one of the preceding claims, wherein the at least one phosphor region ( 13 - 15 ) comprises a plurality of phosphor regions, which in a regular pattern on the support surface ( 12 ) are distributed. Lighting device ( 11 ; 31 ; 41 ) according to one of the preceding claims, wherein the support surface ( 12 ) is a surface of a heat sink. Lighting device ( 11 ; 31 ; 41 ) according to one of the preceding claims, wherein the support surface ( 12 ) a surface of a plastically deformable plate ( 16 ). Lighting device ( 11 ; 31 ; 41 ) according to one of the preceding claims, wherein all semiconductor light sources ( 18 - 20 ) Emit light of the same color. Lighting device ( 11 ; 31 ; 41 ) according to one of the preceding claims, wherein the light of the lighting device ( 11 ; 31 ; 41 ) in a far field to a mixed light of substantially the same color.

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