Blue diffuser in white / white application to create a blue sky

Abstract

A luminaire comprising two light source groups, each comprising at least one light source (1, 2), and an optical element (3), wherein the at least one light source (1) of the first light source group is designed to emit light with a first intensity profile (10) for radiating a first light color, which has a first mean intensity value averaged over a wavelength interval between 500 nm and 600 nm, and wherein the at least one light source (2) of the second light source group is designed to emit light with a second intensity profile (20) for radiating a second light color, which has a second mean intensity value averaged over the wavelength interval, wherein the first and the second intensity profiles differ, wherein the light sources (1, 2) of the light source groups are arranged on a light entry side of the optical element (3) and are thus arranged relative to the optical element (3),that the light emitted by them enters the optical element (3) at the light entry side of the optical element (3) before exiting at its light exit side, characterized in that the optical element (3) has a transmittance which is less than 60%, in particular between 5% and 60%, in a first wavelength range having a width of at least 50 nm, in particular of at least 80 nm, and which is more than 70%, in particular more than 80%, in a second wavelength range having a width of at least 30 nm, in particular at least 60 nm, and does not overlap with the first wavelength range, wherein a first intensity averaged over the first wavelength range and a second intensity averaged over the second wavelength range of the first intensity profile (10) each amount to at least 10%, in particular at least 15% of the first intensity mean value,and wherein a first intensity averaged over the first wavelength range and a second intensity averaged over the second wavelength range of the second intensity profile (20) are each at least 10%, in particular at least 15% of the second intensity mean value, wherein the at least one light source (1) of the first light source group is designed to emit a warm white light color with a color temperature of less than 3,500 K, and wherein the at least one light source (2) of the second light source group is designed to emit a cold white light color with a color temperature of more than 4,000 K.,

Description

[0001] The invention relates to a luminaire comprising two light source groups, each comprising at least one light source, and an optical element according to the preamble of claim 1.

[0002] Generic luminaires are used to emit light with a specific light color that can be predetermined by the light sources of the two light source groups. The light sources of both light source groups are designed to emit visible light. The at least one light source of the first light source group is designed to emit light with a first intensity profile for emitting a first light color, which has a first average intensity value averaged over a wavelength interval between 500 nm and 600 nm. The at least one light source of the second light source group is designed to emit light with a second intensity profile for emitting a second light color, which has a second average intensity value averaged over the wavelength interval. The first and the second intensity profiles differ. Thus, the first and the second light color differ, i.e.the light colors emitted by the light sources of different light source groups. Particularly preferably, all light sources assigned to exactly one of the light source groups are designed to emit light with an identical intensity profile. By providing two different light source groups, each of whose light sources emits light with different intensity profiles, a generic luminaire can emit a mixed color resulting from a mixture of the first and second light colors. Accordingly, the mixed color emitted by the luminaire can be specifically adjusted by carefully selecting the intensity profiles of the light sources in the light source groups.Particularly preferably, luminaires of this type comprise a control unit configured to control and / or dim the light sources of the first light source group independently of the light sources of the second light source group. The luminaire is configured to emit different mixed colors depending on the dimming of the light sources of the different light source groups.

[0003] The essential basic idea on which generic luminaires are based is that a light source can always be assigned an intensity curve that characterizes the light emitted by it. This intensity curve is standardized with respect to the maximum of the intensity curve and thus does not indicate an absolute intensity but rather the distribution of the intensity emitted by the light source as a function of wavelength. The maximum is the maximum value of the intensity curve in the visible wavelength range. The absolute intensity with which a light source emits light results from the operating current supplied to the light source. The absolute value of the intensity is therefore determined by the operating current flowing through the light source, whereas the intensity curve and thus the light color is determined by the intensity curve assigned to the light source and characteristic of the light source.In general, the light color results from the intensity curve of the light emitted by a light source in the visible wavelength range, so that this intensity curve can also be specified instead of the light color to characterize a light source. By using two light sources, each emitting light with a different intensity curve, i.e. each of which is assigned a different intensity curve, the luminaire ultimately emits light with an intensity curve that results from the superposition of the different intensity curves of the different light sources. By providing two light sources with predefined properties, a mixed color can be emitted by the luminaire that is different from the light colors assigned to the two light sources.When providing independent dimming of the light sources of the two light source groups, the luminaire ultimately emits light with an intensity curve which, depending on the dimming of the various light source groups, is composed to different extents of the intensity curve of the light sources of the first light source group and the intensity curve of the light sources of the second light source group.

[0004] This basic idea underlying generic luminaires is particularly relevant when LEDs are used as light sources. The present invention therefore relates in particular to a luminaire in which the light sources are designed as LEDs. LEDs, in particular colored LEDs, usually have a narrow intensity profile, i.e. an intensity profile that only has a significant value in a wavelength range with a relatively narrow width. Therefore, for example, a generic luminaire often contains a light source group with light sources having a warm white light color and a light source group with light sources having a cool white light color, so that pleasant room lighting can be created by mixing the different light sources or the different intensity profiles of warm white and cool white light.In particular, the nuances of the white light color ultimately produced by the luminaire can be adjusted by a user by dimming the different light source groups. It is also known to provide a luminaire that emits light with a colored hue, i.e., a light color other than white, such as red, blue, or green, and also LEDs that emit light with a warm white or cool white light color. This allows for pleasant room lighting with a user-selectable background color, such as red, blue, or green.

[0005] However, it has proven problematic for generic luminaires to provide a luminaire that emits light in a color desired by a user, for example, red, blue, or green, where this color can be varied in nuances. Because colored light sources, i.e., light sources that emit colored light rather than white, such as red, blue, or green, often have a very narrow intensity gradient, i.e., a very narrow spectral width, the color emitted by the luminaire can only be varied to a very limited extent by combining this light color with a warm white or cool white light color in different intensity ratios.Furthermore, generic luminaires have the disadvantage that, due to the narrow spectral width of the light emitted by the colored light source, the color tone emitted by the luminaire is perceived by the user as inharmonious. This can only be remedied with generic luminaires by providing a large number of different light source groups in one luminaire, each of whose light sources emits light with a different light color. For example, a generic luminaire can have one light source group with a warm white light color, another light source group with a cool white light color, another light source group with a light color in a first shade of red, and another light source group with a light color in a second shade of red.Subsequently, by independently dimming the different light source groups, a variation in the red hue emitted by the luminaire can be achieved. However, the implementation of such a generic luminaire is costly and complex due to the large number of different light source groups that must be provided. Furthermore, it is known from document US 2016 / 0243379 A1 that, in order to set a desired color spectrum of the light emitted by a luminaire, a diffuser element is provided in front of a specific light source. This diffuser element is tuned to this light source and transmits only that portion of the light emitted by the light source that lies within a specific wavelength range.

[0006] The present invention is based on the object of providing a luminaire which enables the emission of light with a color tone which is pleasant for a user and which at least partially eliminates at least some of the disadvantages of generic luminaires described above.

[0007] As a solution to the technical problem underlying the invention, the invention proposes a luminaire with the features of claim 1. The luminaire according to the invention comprises two light source groups, each comprising at least one light source, and an optical element. The at least one light source of the first light source group is designed to emit light with a first intensity profile for radiating a first light color, which has a first mean intensity value averaged over a wavelength interval between 500 nm and 600 nm. The at least one light source of the second light source group is designed to emit light with a second intensity profile for radiating a second light color, which has a second mean intensity value averaged over the said wavelength interval. The first and the second intensity profiles differ from one another.Thus, the two light colors also differ from each other. The luminaire according to the invention can have further properties that were explained in connection with generic luminaires. It is essential that the intensity curve characterizes the light source, as the light color of the light emitted by the light source is derived from the intensity curve. The intensity curve indicates the radiant intensity of the light source as a function of the wavelength for a specific light source, expressed as a percentage of the maximum intensity present at a specific wavelength.Particularly preferably, the intensity curve is determined when an LED is operated at its nominal current, wherein it is assumed that the intensity curve varies only insignificantly when the operating current of the light source varies within the operating current range intended for the light source in the luminaire, so that the intensity curve measured at the nominal current is assumed to be the characteristic intensity curve of the light source. It should be noted that, of course, in a luminaire according to the invention, the operating current can only be varied within limits predetermined by the configuration of the luminaire, for example due to the operating device if only switching the luminaire on and off is possible, or due to the operating device and a control device if dimming is possible.In the luminaire according to the invention, the optical element has a transmittance that is less than 60% in a first wavelength range, which has a width of at least 50 nm, and that is more than 70% in a second wavelength range, which has a width of at least 30 nm and does not overlap with the first wavelength range. The transmittance of the optical element is wavelength-dependent and indicates which proportion of the intensity of the light radiated by the light sources of the luminaire onto a light entry side of the optical element passes through the optical element and exits from the light exit side. The values ​​specified for the transmittance for a wavelength range correspond to the transmittance value averaged over the wavelength range; more preferably, the transmittance has the stated value consistently over at least 90%, in particular over 100% of the wavelength range.The first wavelength range particularly preferably has a width of at least 80 nm, in particular at least 100 nm. The second wavelength range particularly preferably has a width of at least 50 nm, in particular at least 60 nm, in particular at least 70 nm, in particular a width between 30 nm and 100 nm. The transmittance in the first wavelength range is particularly preferably more than 5%, in particular more than 10%, in particular more than 15% and at the same time less than 60%, in particular less than 40%, in particular less than 30%. The transmittance in the second wavelength range is particularly preferably more than 80%, in particular more than 90%. The two wavelength ranges are particularly preferably spaced apart from one another by at least 30 nm, in particular at least 50 nm, in particular at least 70 nm. The two wavelength ranges together are particularly preferably in a range between 420 nm and 720 nm.Preferably, both wavelength ranges each run uninterrupted between their limiting wavelengths. In the luminaire according to the invention, a first intensity of the first intensity profile averaged over the first wavelength range and a second intensity of the first intensity profile averaged over the second wavelength range each amount to at least 10%, in particular at least 15%, of the first intensity mean value. Likewise, a first intensity of the second intensity profile averaged over the first wavelength range and a second intensity of the second intensity profile averaged over the second wavelength range each amount to at least 10%, in particular at least 15%, of the second intensity mean value. The light sources of both light source groups thus emit a substantial proportion of the light they emit in the first and second wavelength ranges.Particularly preferably, the first intensity profile has a value of at least 5%, in particular at least 10%, of the first mean intensity value in both the first and the second wavelength ranges, and moreover the second intensity profile has a value of at least 5%, in particular at least 10%, of the second mean intensity value in both the first and the second wavelength ranges. This can ensure that the light sources of both light source groups continuously emit a relevant intensity proportion of the total intensity emitted by them across both wavelength ranges. This can particularly preferably ensure that the luminaire emits light with a color tone ora light colour determined by the optical element, wherein the intensity profile of the light emitted by the luminaire runs continuously well away from zero within a large spectral range, thereby ensuring that the light emitted by the luminaire is perceived as pleasant by a user. At this point it should be noted that the light emitted by the luminaire is of course light which exits from the optical element at its light exit side, after having previously entered at the light entry side of the optical element, wherein the light sources of the light source groups are arranged at the light entry side of the optical element and are arranged relative to the optical element in such a way that light emitted by them enters the optical element at the light entry side of the optical element.

[0008] The luminaire according to the invention offers significant advantages compared to generic luminaires. By providing an optical element with a fixed transmittance, which has a relatively low value in a first wavelength range and a relatively high value in a second wavelength range, the light color emitted by the luminaire can be significantly influenced by the optical element. Since both wavelength ranges are considerably broad and, moreover, the light sources of both light source groups emit a significant proportion of their emitted light in both wavelength ranges, the light color emitted by the luminaire ultimately results from the combination of the intensity profiles of the light sources of the two light source groups and the filtering effect of the optical element.This makes it possible to emit light in a light color that is particularly pleasant for a viewer, since the color tone of the light color, e.g. blue, green or red, is not achieved by adding a white light source to a narrowband colored light source, but rather by combining any broadband light sources from the two light source groups with the properties of the optical element that filter to a color tone. It has proven particularly advantageous to provide a control unit in the luminaire according to the invention by means of which the light sources of the first light source group can be controlled and / or dimmed independently of the light sources of the second light source group. This enables a shift in the color tone emitted by the luminaire, so that different nuances of the color tone emitted by the luminaire can be set by a user.A significant contribution to this is that the intensity profiles of the light sources in the two light source groups differ from one another, that the wavelength ranges in each case have a considerable width, that the intensity profiles of the light sources in both light source groups have a value significantly different from zero in both wavelength ranges and that the filter properties of the optical element, i.e. the transmittance, are significantly different in the two wavelength ranges. Only in this way can it be ensured that a specific color tone is defined via the optical element, for example red, green or blue, and that this color tone is varied in nuances by varying the ratio of the intensity of the light emitted by the light sources in the first light source group to the intensity of the light emitted by the light sources in the second light source group.It has proven particularly advantageous to provide the intensity profiles of the light source groups so that they differ from one another in such a way that the ratio of the second average intensity of the first intensity profile to the first intensity mean value differs by at least 20%, in particular by at least 30%, in particular by at least 50% of its value from the ratio of the second average intensity of the second intensity profile to the second intensity mean value.It has proven particularly advantageous to provide the intensity profiles of the light source groups so that they differ from one another in such a way that the ratio of the first averaged intensity of the first intensity profile to the first intensity mean value differs by at least 20%, in particular by at least 30%, in particular by at least 50% of its value from the ratio of the first averaged intensity of the second intensity profile to the second intensity mean value.

[0009] According to the invention, the at least one light source of the first light source group is designed to emit a warm white light color with a color temperature of less than 3500 K, and the at least one light source of the second light source group is designed to emit a cool white light color with a color temperature of more than 4000 K, in particular more than 4500 K. By the first light source group emitting a warm white light color and the second light source group emitting a cool white light color, the combination with the optical element in the luminaire according to the invention ensures that a color tone predetermined by the wavelength-dependent transmittance of the optical element can be emitted by the luminaire in a finely nuanced manner, wherein, in particular when the two light source groups are dimmed independently of one another, a continuous change in the color tone emitted by the luminaire between two specified color tones can be ensured.Particularly preferably, the luminaire has a control unit which is designed to control and / or dim the two light source groups independently of one another.Particularly preferably, the control unit is designed to ensure that the luminaire emits light with a first defined light color by switching on the first light source group and off the second light source group, and to ensure that the luminaire emits light with a second defined light color by switching on the second light source group and off the first light source group, wherein the control unit is designed to enable, by dimming the two light source groups independently of one another, the luminaire to be suitable for emitting light with any possible light color that is defined in a color space by a color locus that lies on a line, in particular on a continuous line that connects the two color loci in the color space that are assigned to the two defined light colors. The two color loci are preferably both in the visible range of the color space.

[0010] Particularly preferably, the optical element is designed to be diffusely translucent. In this embodiment, the optical element is therefore not transparent. This has the particular advantage that light entering the optical element from light sources of different light source groups is diffusely scattered in the optical element, which can contribute to a mixture of the different light colors emitted by the light sources of the different light source groups. Furthermore, the diffusely translucent design of the optical element has the advantage that a direct view from the outside through the optical element onto the light sources of the light source groups is at least limited, if not completely prevented.Particularly preferably, the at least one light source of the first light source group and the at least one light source of the second light source group are arranged relative to the optical element such that light emitted by the various light sources exits the optical element in a homogeneously mixed state. This can provide the luminaire with emission properties that are particularly pleasant for a viewer. In some embodiments, the optical element can comprise various sub-elements. For example, the optical element can comprise a filter element that defines the transmittance of the optical element, and a lens element that is designed to direct light that enters the optical element from the light sources of the light source groups and exits at a light exit side of the optical element.

[0011] In one embodiment, the first light source group and the second light source group each comprise a plurality of light sources, wherein all light sources of one of the light source groups are designed to emit light with the same intensity profile. At this point, it should be generally noted that the two light source groups can each have a plurality of light sources assigned to them, wherein the properties of the at least one light source of a light source group explained above for various embodiments apply to all light sources of the light source group. Particularly preferably, the light sources of the first light source group are arranged next to one another along a first straight line and the light sources of the second light source group are arranged next to one another along a second straight line, wherein the two straight lines run parallel to one another and the luminaire is elongated along the straight line.In this embodiment, the optical element is also elongated and extends across all light sources of the two light source groups. The described arrangement particularly well ensures that the light sources and optical element are arranged in such a way that the optical element ensures a homogeneous mixture of the light with the different light colors emitted by the light sources of the different light source groups across the entire elongated extent of the luminaire.

[0012] In one embodiment, the first wavelength range comprises a range between 580 nm and 620 nm, in particular between 570 nm and 630 nm, wherein the second wavelength range comprises a range between 440 nm and 460 nm. This embodiment can, for example, provide a luminaire suitable for emitting light with a pleasant blue hue, wherein the provision of a control unit suitable for dimming the two light source groups independently of one another can ensure that this blue light color can be varied to different shades of blue. In one embodiment, the luminaire has a plurality of optical elements, wherein each of the optical elements is assigned a first light source group with at least one first light source and a second light source group with at least one second light source.The interaction of the optical element and associated light source groups can be provided as in the previously explained embodiments. In a particularly advantageous embodiment, different optical elements, each of which is assigned at least two light source groups as explained, each have different transmittances. For example, this can enable each arrangement consisting of an optical element and associated light source groups to emit light with a specific primary color (e.g., blue, red, or green), with different arrangements each being suitable for emitting light with a different primary color.For example, a first optical element can have a transmittance whose second wavelength range covers a range between 440 nm and 460 nm, a second optical element can have a transmittance whose second wavelength range covers a range between 650 nm and 670 nm, and a third optical element can have a transmittance whose second wavelength range covers a range between 520 nm and 540 nm. Such a luminaire particularly preferably has a control unit with which not only the various light source groups of an arrangement but also the light source groups of different arrangements can be controlled independently of one another.Depending on the number of different arrangements provided, a very wide range of the visible spectrum can be addressed almost continuously, so that the luminaire is suitable for emitting light with a light colour that is assigned to any colour location within this range.

[0013] The invention is explained in more detail below using an embodiment with reference to four figures.

[0014] They show: Fig. 1: in a schematic principle representation a cross-section through a section of a luminaire according to the invention; Fig. 2: in a first schematic explanatory representation, the effect of the optical element in a luminaire according to the invention; Fig. 3: in a second schematic explanatory representation, the effect of the optical element in a luminaire according to the invention; Fig. 4: a third schematic explanatory representation for explaining the function of the luminaire according to Fig. 1 emitted light.

[0015] In Fig. Figure 1 shows a schematic cross-section through a section of a luminaire according to the invention. This section does not show all the components included in the luminaire, but only two light sources 1, 2, the optical element 3, and a support plate 4 of the luminaire. The illustration according to Fig. 1 is purely schematic; further components of the luminaire, such as a housing, an operating device or a circuit board, are not shown. The luminaire according to the invention is elongated along a longitudinal direction, wherein Fig. 1 shows a cross-section perpendicular to the longitudinal direction. The luminaire comprises two light source groups. The first light source group has a plurality of first light sources 1 arranged next to one another along a first straight line, wherein the first straight line runs parallel to the longitudinal direction. The second light source group has a plurality of second light sources 2 arranged next to one another along a second straight line, which runs parallel to the first straight line and which, as shown in Fig. 1, is spaced perpendicular to the longitudinal direction from the first straight line. The optical element 3 is also elongated. The optical element 3 is diffusely translucent and is arranged relative to the light sources 1, 2 of the luminaire such that the light emitted by the light sources 1, 2 enters the optical element 3 at a light entry side of the optical element 3, wherein the light emitted by different light sources 1, 2 is mixed within the optical element 3 and the mixed light exits at the light exit side of the optical element 3.

[0016] In the described embodiment, all first light sources 1 have an identical first intensity curve, and all second light sources 2 have an identical second intensity curve. Of course, for light sources that have an identical intensity curve, negligible variations in the intensity curve can occur due to manufacturing technology, which only lead to a change in the light color that is practically irrelevant to an observer. Thus, even in the presence of such negligible differences, the intensity curves are referred to as identical. The fact that a light source 1, 2 "has an intensity curve" is to be understood that the light source 1, 2 is designed to emit light with an intensity curve, wherein the intensity curve is characteristic of the light source 1, 2 and indicates the light color with which the light source 1, 2 emits light.

[0017] In Fig. 2 shows a first schematic explanatory illustration of the effect of the optical element 3 in the described embodiment of the luminaire according to the invention, with reference being made here to the first intensity profile 10 of the first light sources 1 of the luminaire and the transmittance of the optical element 3. In Fig. 3 shows a second schematic explanatory diagram of the effect of the optical element 3 with reference to the second intensity profile of the second light sources 2 of the luminaire and the transmittance of the optical element 3. In Fig. 2 shows the first intensity curve 10 of the first light sources 1. As explained, the first intensity curve 10, normalized to the maximum of the first intensity curve 10, indicates the curve of the intensity emitted by the first light sources 1 as a function of the wavelength. Fig. 2 also shows the intensity curve 13 of the light emitted by the luminaire for the case where only the first light sources 1 are switched on and the second light sources 2 are switched off. Fig. 2, it can be seen that the optical element 3 causes a shift in the maximum of the intensity profile, since it has a significantly lower transmittance in a first wavelength range than in a second wavelength range. In the present case, the first wavelength range comprises a range between 570 nm and 630 nm, with the second wavelength range comprising a range between 430 nm and 470 nm. While the first intensity profile 10 corresponds to a warm white light color, the luminaire radiates in the state shown in Fig. 2, light with a subtle blue hue according to the intensity curve 13, since the maximum of the intensity curve 13 of the light emitted by the luminaire lies in the blue region of the spectrum.

[0018] In Fig. 3 shows the second intensity curve 20 of the second light sources 2. As explained, the second intensity curve 20, normalized to the maximum of the second intensity curve 20, indicates the curve of the intensity emitted by the second light sources 2 as a function of the wavelength. Fig. 3 also shows the intensity curve 23 of the light emitted by the luminaire for the case where only the second light sources 2 are switched on and the first light sources 1 are switched off. Fig. 3 it can be seen that the optical element 3 causes a deformation of the intensity profile. While the second intensity profile 20 corresponds to a cold white light color, the luminaire radiates in the state shown in Fig. 3, light with a blue hue according to the intensity curve 23, since the long-wave portion of the light emitted by the second light sources 2 has been filtered out to a considerable extent by the optical element.

[0019] In Fig.4 shows a two-dimensional image of a color space. In this color space, a first color location 100 is shown, which corresponds to a light blue to white color, and a second color location 200, which corresponds to a deep blue color. The luminaire according to the invention has a control unit designed to control the first light sources 1 independently of the second light sources 2. In an operating state in which the control unit controls the light sources 1, 2 such that only the first light sources 1 emit light, the luminaire emits light with a light color that corresponds to the first color location 100. In an operating state in which the control unit controls the light sources 1, 2 such that only the second light sources 2 emit light, the luminaire according to the invention emits light with a light color that corresponds to the second color location 200.By dimming light sources 1 and 2 of the light source groups, the ratio of the intensity emitted by the first light sources 1 to the intensity emitted by the second light sources 2 can be changed. By dimming in this way, the luminaire can be adjusted to emit any desired blue hue that lies on a line connecting the two color coordinates 100 and 200. List of reference symbols 1 first light source 2 second light source 3 optical element 4 carrier plate 10 first intensity curve 20 second intensity curve 13, 23 intensity curve emitted by the luminaire 100 first color location 200 second color location

Claims

[1] A luminaire comprising two light source groups, each comprising at least one light source (1, 2), and an optical element (3), wherein the at least one light source (1) of the first light source group is designed to emit light with a first intensity profile (10) for radiating a first light color, which has a first mean intensity value averaged over a wavelength interval between 500 nm and 600 nm, and wherein the at least one light source (2) of the second light source group is designed to emit light with a second intensity profile (20) for radiating a second light color, which has a second mean intensity value averaged over the wavelength interval, wherein the first and the second intensity profiles differ, wherein the light sources (1, 2) of the light source groups are arranged on a light entry side of the optical element (3) and are thus arranged relative to the optical element (3),that the light emitted by them enters the optical element (3) at the light entry side of the optical element (3) before exiting at its light exit side, , characterized bythat the optical element (3) has a transmittance which is less than 60%, in particular between 5% and 60%, in a first wavelength range which has a width of at least 50 nm, in particular of at least 80 nm, and which is more than 70%, in particular more than 80%, in a second wavelength range which has a width of at least 30 nm, in particular at least 60 nm, and does not overlap with the first wavelength range, wherein a first intensity averaged over the first wavelength range and a second intensity of the first intensity profile (10) averaged over the second wavelength range each amount to at least 10%, in particular at least 15% of the first intensity mean value, and wherein a first intensity averaged over the first wavelength range and a second intensity of the second intensity profile (20) averaged over the second wavelength range each amount to at least 10%,in particular at least 15% of the second mean intensity value, wherein the at least one light source (1) of the first light source group is designed to emit a warm white light color with a color temperature of less than 3,500 K, and wherein the at least one light source (2) of the second light source group is designed to emit a cold white light color with a color temperature of more than 4,000 K., [2] Luminaire according to claim 1, characterized by that the luminaire has a control unit which is designed to control and / or dim the two light source groups independently of one another. [3] Luminaire according to one of the preceding claims, characterized by that the transmittance in the first wavelength range is less than 30%, in particular between 5% and 30%, and / or that the transmittance in the second wavelength range is more than 90%. [4] Luminaire according to one of the preceding claims, characterized by that the optical element (3) is diffusely translucent. [5] Luminaire according to one of the preceding claims, characterized by that the first wavelength range has a width of at least 100 nm and that the second wavelength range has a width between 30 nm and 100 nm. [6] Luminaire according to one of the preceding claims, characterized by that the first intensity profile (10) has a value of at least 5%, in particular at least 10%, of the first intensity mean value in both the first and the second wavelength ranges, and that the second intensity profile (20) has a value of at least 5%, in particular at least 10%, of the second intensity mean value in both the first and the second wavelength ranges. [7] Luminaire according to one of the preceding claims, characterized bythat the at least one light source (1) of the first light source group and the at least one light source (2) of the second light source group are arranged relative to the optical element (3) in such a way that light emitted by the various light sources (1, 2) emerges from the optical element (3) in a homogeneously mixed state. [8] Luminaire according to one of the preceding claims, characterized by that the first wavelength range comprises a range between 580 nm and 620 nm, in particular between 570 nm and 630 nm, and that the second wavelength range comprises a range between 440 nm and 460 nm. [9] Luminaire according to one of the preceding claims, characterized byin that the first light source group and the second light source group each comprise a plurality of light sources (1, 2), wherein all light sources (1, 2) of a light source group are designed to emit light with the same intensity profile, wherein the light sources (1) of the first light source group are arranged next to one another along a first straight line and the light sources (2) of the second light source group are arranged next to one another along a second straight line, wherein the two straight lines run parallel to one another and the luminaire is designed to be elongated along the straight line.

Images