WO2013150108A1 - Illumination device - Google Patents

Description

 description

Beichtuchtungsrichtung

Technical area

The present invention relates to a Beleuchtungsvor ^¬ direction comprising at least one first LED, the out ^¬ sets to deliver radiation in a first wavelength range, and at least one second LED, which is designed to emit radiation in a second wavelength range, wherein the second wavelength range from the first Wavelength range is different.

State of the art

In particular, the invention relates to the problem of the color mixture of radiation emitted by LEDs and located in different wavelength ranges. Such color mixing is necessary to optimize color rendering and color matching. For example, the mixture of the radiation of at least two differently colored LEDs is necessary for a very good color reproduction for sales lights or museums or for achieving a color distinction. On the one hand, the spacing of these LEDs should be about 10 mm or more to avoid thermal problems. On the other hand, the distance should be minimized in order to be able to mix ^colors more easily and to prevent color shadows and their undesired effects. Namely, if the distance of the LEDs from each other is too large, throwing an obstacle, which is between the lighting device and the area to be illuminated, color shade. The requirements for avoiding thermal problems on the one hand and Prevention of color shadows on the other hand are therefore contradictory.

This problem becomes greater, the larger the luminous flux to be achieved by means of such a lighting device should be. For lighting purposes, as envisaged by the present invention, luminous fluxes of 2000 Im, in particular even luminous fluxes of more than 3000 Im should be producible with high quality.

From the state of the art so-called color mixing lenses are known in which the radiation of several LEDs is mixed using lenses and reflectors with multiple deflection. For this purpose, for example three or four, a lens is limited to a ^¬ number of LEDs mounted. The LEDs are located at the bottom of a hemispherical reflector into which the lens is fitted. Such a device for color mixing is known for example under the name SPUTNIK-Z of the company LEDIL. Such a lighting device is a kind of collimator lens with light-mixing properties. It smoothes the radiation pattern and produces a uniform color distribution over the entire radiation angle. Due to thermal problems, the number of which can be arranged in such a lighting device LEDs per ^¬ but limited. Thus, on the one hand, the luminous flux that can be generated thereby is limited, and on the other hand, the number of colors to be mixed.

The light distribution achievable with such a device is circular (SPUTNIK-Z Smooth Spot) or oval (SPUTNIK-Z oval) and symmetrical in each case. For further prior art reference is made to US Pat. No. 7,322,731 and to AJW Whang, PC Li, Y. Y. Chen: "Guiding light from the LED array via tapered light tip for illumination systems design", Journal of Technology, 2009.

Presentation of the invention

The object of the present invention is therefore to improve a generic lighting device such that the generation of high luminous flux is made possible with the lowest possible color shade. This object is achieved by a Beleuchtungsvorrich ^¬ tion with the features of claim 1.

The present invention is based on the finding that the radiation of a plurality of LEDs can be mixed when a generic illumination device is extended by a radiation mixing chamber having a height, a width and a length, the radiation mixing chamber having a closed bottom, at least a first and a second side wall in the longitudinal Rich ^¬ tung, at least a third and a fourth side wall in the width direction and located opposite the bottom opening, said at least one first and the at least one second LED are arranged at the bottom of the radiation mixing chamber. By such a radiation ^¬ mixing chamber, it is possible to arrange an arbitrary number of LEDs on the ground, with the output of the LEDs radiation mixed by reflection at the side walls of the radiation mixing chamber before it opposite the radiation mixing chamber through the bottom Opening leaves. In this way, therefore, very high luminous fluxes can be generated without the risk of color shadows.

The cross-section of the radiation mixing chamber is particularly preferably at least sectionally rectangular, parabolic, circular-sector-shaped, triangular or elliptical in the longitudinal direction, or it comprises combinations of these forms. This allows the type of mixing of the radiation emitted by the LEDs to be influenced as desired. In this connection, the side walls in the width direction are respectively tuned to the cross section of the radiation mixing chamber in the longitudinal direction, i. choose their shape so that the result is a - except for the opening - closed radiant mixing chamber. For circular sector shaped cross section, i. the radiation mixing chamber has a substantially cylindrical shape, the bottom of the radiation mixing chamber for the purposes of the present invention is the area where the LEDs are arranged. In this respect, the LEDs are not arranged on a flat surface, but on a circular sector-shaped surface. Of course, mixed forms of the specified shapes are possible, for example, a radiation mixing chamber whose side walls are each circular sector-shaped or parabolic, but still has a flat bottom.

Preferably, the opening has a smaller area than the floor. In this way, a particularly good mixing of the radiation emitted by the LEDs is achieved. The resulting color shadows are minimal. The cross-sectional area of the radiation mixing chamber may increase at least in sections from the opening to the bottom. It can be provided that the cross-sectional area of the radiation from the mixing chamber Öff- voltage widens steadily to the ground, or widens abschnittswei ^¬ se and narrows again. In this way, the quality or the result of the mixture can be purposefully influenced.

Preferably, at least one side wall is designed to be reflective for the radiation in the first and in the second wavelength range, in particular by mirroring or by at least one metallic coating or by white coloration. By this measure, a particularly high efficiency can be achieved, whereby thermal problems are further reduced.

Preferably, at least three LEDs are provided, which are arranged in a row. However, at least four LEDs may be provided which are arranged in at least two rows. In this connection, the LEDs may be equidistant or different from each other. Depending on the arrangement of the LEDs, the radiation mixing chamber can therefore be linear or non-linear.

It has proven to be advantageous if the base and / or at least one side wall are designed as heat sinks or are coupled to a heat sink. In contrast to the prior art, a particularly good dissipation of the resulting heat can be achieved in this way. This allows the packing density increase and thus reduce the dimensions of a lighting device according to the invention.

, When the LEDs are so arranged to the sides ^¬ walls that at least a part of emanating from the LEDs radiation is reflected at least at least once on a side wall before it exits through the aperture from the radiation mixing chamber is advantageous. In this way, a particularly good mixing of the radiation emanating from the LEDs is achieved. The exiting through the opening mixed radiation is characterized by be ^¬ Sonders high homogeneity.

A further improvement in the mixing of the radiation can be achieved if at least one of the sidewalls in the longitudinal direction and / or in the width direction and / or height direction and / or in the height direction is smooth and / or corrugated and / or curved and / or with concave and / or convex lenses is occupied.

The lighting device may further include at least one lens array disposed on the opening side of the radiation mixing chamber. In this way, beam shaping can be performed. While in the known devices for light mixing only a symmetrical radiation distribution can be generated, an asymmetrical light emission can be achieved by means of a lighting device according to the invention. Only through an asymmetric Strahlungsvertei ^¬ development can be ensured a uniform irradiance on the surface to be illuminated. A circular light emission, as known from the prior art, leads to a light to be illuminated Area to a diffuse distribution, the weaker the farther one moves away from the symmetry axis and the point of symmetry. With regard to Beleuchtungszwe ^¬ bridge this is undesirable. By means of such further development of a lighting device according to the invention, this deficiency can be remedied.

In this context, it is particularly preferred if a focal point of the at least one lens arrangement is arranged in the opening of the radiation mixing chamber, in particular centrally in the width direction. The at least one Lin ^¬ senanordnung may be elliptical, hyperbolic or parabolic. In this way, any light ^¬ strength distributions can be achieved.

The at least one lens arrangement can be at least partially reflective, in particular mirrored, ^{ausgebil ¬} det. In this way, the efficiency ei ^¬ ner lighting device according to the invention can be further increased.

Particularly preferably, at least one first and one second lens arrangement are provided, which are arranged in the width direction. Thus, the radiation distributions generated by the per ^¬ weiligen lens assembly can be combined, so that the spectrum of the achievable radiation distributions is extended. In this case, the first and the second lens arrangement may be formed as a singular lens arrangement or as integrated lens arrangements.

Particularly preferably, the at least one Linsenanord ^¬ voltage is formed such that egg in the width direction ne asymmetric radiation distribution results. As already mentioned, this makes it possible to achieve radiation distributions which result in a constant irradiance on a surface to be illuminated. For this purpose, the at least one lens arrangement may be inclined in the width direction.

The illumination device may further comprise a reflector which is arranged and / or formed such that an asymmetrical radiation distribution results. For example, the reflector outside the Strah ^¬ lung mixing chamber and to the radiation passing through the opening may be arranged that the desired asym ^¬ metric radiation distribution results.

The illumination device may in particular comprise at least a first radiation mixing chamber and a second radiation mixing chamber. As a result, symmetrical radiation distributions can be achieved, which nevertheless lead to a homogeneous illumination of the surface to be illuminated. Here, the first and the second ^{Strahlungsmischkam ¬} mer be arranged parallel or perpendicular to each other. The lighting device may also include at least a first, a second and a third radiation ^¬ mixing chamber. In this context, the first, the second and the third radiation mixing chamber can be arranged parallel, rectangular or triangular to each other.

Further preferred embodiments emerge from the subclaims. Short description of the drawing (s)

Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. Show it:

1 shows a schematic representation of a first embodiment of a lighting device according to the invention;

Fig. 2 further embodiments of an inventive

 Lighting device with different contour of the side walls;

3 shows a further embodiment of a lighting device OF INVENTION ^¬ to the invention with side walls that are ground-opening side and grooved.

4 shows exemplary embodiments of a lighting device according to the invention, in which a lens arrangement is mounted on the opening side;

Fig. 5 shows an embodiment of an inventive

 Lighting device with multiple lens arrays;

FIG. 6 shows the asymmetrical radiation distribution achievable by means of a plurality of lens arrangements; FIG.

Fig. 7 shows an embodiment of an inventive

Illumination apparatus having two radiation mixing chambers, in each of which several Linsenanord ^¬ voltages are arranged on the opening side of the respective radiation mixing chamber; FIG. 8 shows the radiation distribution achievable by means of the embodiment of a lighting device according to the invention shown in FIG. 7; FIG.

Figure 9 is a schematic representation of an example of an execution ^{¬ ¬} lighting device according to the invention in which two radiation mixing chambers are arranged at right angles to each other. and

10 is a schematic representation of an embodiment ^¬ example of a lighting ^¬ device according to the invention, in which three radiation mixing chambers are arranged triangular to each other.

Preferred embodiment of the invention

In the different embodiments, the same Bezugszei ^¬ surfaces are used for the same and same-acting elements. These are introduced only once for the sake of clarity.

Fig. 1 shows a schematic representation of an embodiment of a lighting device according to the invention. This comprises a multiplicity of LEDs 12a to 12n, at least two LEDs emitting radiation in different wavelength ranges. However, it is preferred if the wavelength ranges of as many LEDs differ from one another. At least one LED which is provided in the red wavelength range, at least one LED which is emitted in the green wavelength range and at least one LED which emits radiation in the blue wavelength range can be provided. The lighting device 10 comprises a radiation ^¬ mixing chamber 14, with a bottom 16, an opening opposite the bottom 18 and four side walls 20 a to 20 d. The radiation mixing chamber 10 has a height h, a length 1 and a width b. In a preferred ^embodiment , b is 2 cm, 1 5 cm and h 1 cm. The minimum height h has been 2 mm. The maximum height is preferably ^¬ 30 mm.

In the exemplary embodiment of an illumination device 10 according to the invention shown in FIG. 1, both the bottom 16 and the opening 18 and the side walls 20a to 20d are rectangular. Before ^¬ Trains t of the floor 16 and / or the side walls 20a to 20d formed or as a heat sink coupled to a heat sink.

The side walls 20a to 20d are preferably reflective, in particular by mirroring or by a metallic coating or by whitening. In this way it is achieved that radiation incident on the side walls 20a to 20d by the LEDs is reflected before it leaves the opening 18.

The LEDs 12 may have an equidistant distance or a different distance. Even if the LEDs are arranged in a row in Fig. 1, these can be scattered also in any two rows or raised ^¬ arranged.

Fig. 2 shows different embodiments of the side walls of a lighting device according to the invention. In FIG. 2 a) the side walls form a rectangle with the bottom, in FIG. 2 b) the side walls are parabolic. in Fig. 2 c) circular and in Fig. 2 d) triangular. As can be seen from the drawn radiation curve, part of the radiation emitted by an LED 12 is reflected at at least one side wall 20 before it leaves the radiation mixing chamber 14 via the opening 18.

Fig. 3 shows a schematic representation of an embodiment of a lighting device 10 according to the invention, in which the side walls 20b, 20d are formed fluted opening and bottom side, both in the height direction and in the width direction.

4 shows two ^exemplary embodiments of a lighting device 10 according to the invention, each of which comprises a lens arrangement 22 which is arranged on the opening side of the radiation mixing chamber 14. A designated 24 focal point of the respective lens assembly 22 is positioned centrally in the width direction in the opening 18 of the radiation mixing chamber 14.

4 a) shows a parabolic lens arrangement, while FIG. 4 b) shows an elliptical lens arrangement. Other types of lens arrangements may also be provided. Preferably, the back 26 of the lens ^¬ arrangement 22 is formed mirrored, so that a reflector ^¬ gate is formed. Fig. 5 shows an embodiment of a erfindungsge ^¬ MAESSEN lighting device in which three lens arrays are provided 22a to 22c, which are arranged in the width direction. The respective lower focal point 24a, b, c of each elliptical lens arrangement 22a, 22b, 22c lies in the radiation exit surface 18 of the radiation beam. As the radiation exit surface 18 of the radiation mixing chamber 14 is narrow, the rays are directed into the upper lens foci. The resulting luminous intensity distribution, see Fig. 6, is a function of the number and shape of the elliptical lens arrays 22a, 22b, 22c. By this measure, an asymmetrical radiation distribution 28 can be achieved on a surface to be illuminated, as shown in Fig. 6. Fig. 7 shows an inventive Beleuchtungsvorrich ^¬ tung 10, the two radiation mixing chambers 14a, 14b, each with three elliptical lens assemblies 22a, 22b, 22c comprises one hand, and 22d, 22e, 22f on the other hand. The spacing of the LEDs 12a, 12b is between 3 mm and 40 mm. The radiation mixing chambers 14a, 14b are arranged parallel to each other. The radiation distributions add up in the far field and yield the radiation distribution shown in FIG. 8. As can be seen from FIG. 8, a symmetrical radiation distribution results, but the radiation distribution does not become weaker toward the outside, as in the case of a circular radiation distribution (Lambertian light emission), but becomes stronger toward the outside. As a result, a homogeneous illumination of a surface to be illuminated can be achieved. FIGS. 9 and 10 show that, due to different arrangements of lens arrangements and radiation mixing chambers, a superposition of individual luminous intensity distributions is possible in order to achieve complex luminous intensity distributions. FIGS. 9 and 10 show, by way of example, orders from above onto the respective radiation mixing chamber, with the lens arrangement being shown for the sake of clarity. were omitted. The arrows indicate the emission direction of maximum intensity. Fig. 9 shows two radiation mixing chambers 14a, 14b, which are arranged perpendicular to each other, while Fig. 10, three radiation ^¬ mixing chambers 14a, 14b, 14c is disposed triangular shape to each other. In principle, any radiation distributions are possible by the respective radiation mixing chambers - are rotated and arranged to each other - even around several axes.

By means of a lighting device according to the invention can be a uniform distribution of radiation erzie ^¬ len as boleffekt for known fluorescent lamps with parameters is the case. In connection with a lighting device according to the invention, it is also possible to use black-colored parabolic mirrors which are colored black on one half. If two radiation mixing chambers, which are provided with such parabolic mirrors, arranged parallel to each other, so no diffused light is generated, but on each side of a peak, as desired.

Claims

claims Including Beyuchtungs device  at least one first LED (12a) adapted to emit radiation in a first wavelength range; and  - at least one second LED (12b) adapted to emit radiation in a second wavelength range, the second wavelength range being different from the first wavelength range;  characterized,  in that the lighting device further comprises at least one radiation mixing chamber (14) having a height (h), a width (b) and a length (1), where ^¬ in the radiation ^{mixing chamber} (14) has a closed bottom (16), at least one first (20b) and a two ^¬ te side wall (20d) in the longitudinal direction, at least one third (20a) and one fourth side wall (20c) in the slab ^¬ direction and a bottom (16) opposite the opening (18), wherein the at least one first (12a) and the at least one second LED (12b) are arranged on the ^bottom (16) of the radiation ^mixing chamber (14). 2. Lighting device according to claim 1,  characterized, that the cross section of the radiation mixing chamber (14) in the longitudinal direction is at least partially rectangular, parabolic, circular sector-shaped, triangular or elliptical or combinations of these forms. Lighting device according to one of claims 1 or 2,  characterized,  that the opening (18) has a smaller area than the bottom (16). Lighting device according to one of claims 1 or 2,  characterized, that the cross-sectional area of the radiation ^¬ mixing chamber (14) from the opening (18) to the bottom (16) at least increased in sections. Lighting device according to claim 4,  characterized, that the cross-sectional area of the radiation ^¬ mixing chamber (14) from the opening (18) to the bottom (16) widens continuously or in sections widens and narrows as ^¬. Lighting device according to one of the preceding claims,  characterized, that at least one side wall (20a, 20b, 20c, 20d) is formed reflective for the radiation in the first and two ^¬ th wavelength region, in particular by mirror coating or by at least one metallic coating or white coloration. 7. Lighting device according to one of the preceding claims, characterized,  in that at least three LEDs (12a, 12b, 12c) are provided which are arranged in a row. 8. Lighting device according to one of the preceding claims,  characterized, that at least four LEDs (12a, 12b, 12c, 12d) are pre see ^¬ which are arranged in at least two rows. 9. Lighting device according to one of claims 7 or 8,  characterized, that the LEDs (12a, 12b, 12c, 12d) has a same From ^¬ stand or have a different distance to each other. 10. Lighting device according to one of the preceding claims,  characterized,  the bottom (16) and / or at least one side wall (20a, 20b, 20c, 20d) are designed as heat sinks or are coupled to a heat sink. 11. Lighting device according to one of the preceding claims,  characterized, that the LEDs (12a, 12b, 12c, 12d) in such a way to Be ^¬ tenwänden (20b, 20d) are arranged such that at least a part of the LEDs (12a, 12b, 12c, 12d) excluded at least once on at least one side wall (20a, 20b, 20c, 20d) is reflected ^¬ before he exits through the opening (18) from the radiation mixing chamber (14). 12. Lighting device according to one of the preceding claims,  characterized,  in that at least one of the side walls (20a, 20b, 20c, 20d) is smooth and / or corrugated and / or curved on the bottom side or opening side in the longitudinal direction and / or in the width direction and / or in the height direction and / or is occupied by concave and / or convex lenses , Lighting device according to one of the preceding claims,  characterized, that it further comprises at least one lens arrangement (22) which is arranged on the opening side of the radiating ^¬ mixing chamber (14). 14. Lighting device according to claim 13,  characterized, a focal point of the at least one lens arrangement (22) is arranged in the opening (18) of the radiation ^mixing chamber (14), in particular centrally in the width direction. 15. Lighting device according to one of claims 12 to 14, characterized, is the at least one lens arrangement (22) ellip ^¬ table, hyperbolic or parabolic. 16. Lighting device according to one of claims 12 to 15,  characterized, the at least one lens arrangement (22) is at least partially reflective, in particular verspie ^¬ gel formed. 17. Lighting device according to one of claims 12 to 16,  characterized, that at least a first (22a) and a second Lin ^¬ nozzle arrangement (22b) are provided which are arranged in the width direction. 18. Lighting device according to claim 17,  characterized,  the first (22a) and the second lens arrangement (22b) are formed as singular lens arrangements or as integrated lens arrangements. 19. Lighting device according to one of claims 12 to 18,  characterized, in that the at least one lens arrangement (22) is designed such that an a-symmetrical radiation distribution (28) results in the width direction. 20. Lighting device according to claim 19,  characterized, the at least one lens arrangement (22) is inclined in slurry ^¬ tenrichtung. 21. Lighting device according to one of claims 12 to 18,  characterized,  the at least one lens arrangement (22) is designed in such a way that a symmetrical radiation distribution results in the width direction. 22. Lighting device according to claim 21,  characterized,  that the lighting device further comprises a reflector which is arranged and / or formed so that an asymmetrical radiation distribution (28). 23. Lighting device according to one of the preceding claims,  characterized,  that the lighting device at least a first Radiation mixing chamber (14a) and a second radiation mixing chamber (14b). 24. Lighting device according to claim 23,  characterized, that the first (14a) and the second radiation ^¬ mixing chamber (14b) are arranged parallel or perpendicular to each other. 25. Lighting device according to one of claims 23 or 24,  characterized, that the lighting device comprises at least a first (14a), a second (14b) and a third radiation ^¬ mixing chamber (14c). 26. Lighting device according to claim 25,  characterized,  in that the first (14a), the second (14b) and the third radiation mixing chambers (14c) are arranged parallel, at right angles or triangularly to each other.