Abstract
A lighting device for generating a white mixed light having controllable spectral characteristics is provided. The lighting device comprises a number of white light sources for each making a contribution to the white mixed light by generating a white light with a respective spectral expression in each case that can be quantitatively characterized, so that the white lights generated by the white light sources can form corner points of a target range for the resulting mixed light in a spectral light parameter space. The lighting device further comprises control electronics for controlling proportional contributions of the white light sources so that the position corresponding to the resulting mixed white light can be varied within the target area spanned on the corner points in the spectral light parameter space.
Claims
1. A lighting device for generating a mixed white light with controllable spectral characteristics, the lighting device comprising: a first light source configured to produce a first white light quantitatively characterized by a first set of spectral characteristics in which at least one of an oversaturated color spectrum and color gamut is prioritized over other characteristics; a second light source configured to produce a second white light quantitatively characterized by a second set of spectral characteristics in which at least one of color rendering and color fidelity is prioritized over other characteristics; a third light source configured to produce a third white light quantitatively characterized by a third set of spectral characteristics in which energy efficiency is prioritized over other characteristics; and control electronics configured to control proportional contributions of the first light source, the second light source, and the third light source to the mixed white light such that the resultant mixed white light is variable by a user in a spectral light parameter space.
2. The lighting device of claim 1, wherein the spectral light parameter space has color rendering (Rf), color gamut (Rg), and color temperature (CCT) as coordinates.
3. The lighting device of claim 1, wherein the first white light, the second white light, and the third white light define, correspondingly, a first point, a second point, and a third point in the spectral light parameter space as corner points of a target area in a color rendering-color gamut (Rf-Rg) plane.
4. The lighting device of claim 3, wherein a position corresponding to the resultant mixed white light is variable substantially within the target area in the spectral light parameter space.
5. The lighting device of claim 1, wherein at least one of: a color rendering (Rf1) of the first light source is greater than a color rendering (Rf3) of the third light source but less than a color rendering (Rf2) of the second light source; and a color gamut (Rg2) of the second light source is greater than a color gamut (Rg3) of the third light source but less than a color gamut (Rg1) of the first light source.
6. The lighting device of claim 5, wherein: a color rendering (Rf1) of the first light source is greater than a color rendering (Rf3) of the third light source but less than a color rendering (Rf2) of the second light source; and a color gamut (Rg2) of the second light source is greater than a color gamut (Rg3) of the third light source but less than a color gamut (Rg1) of the first light source.
7. The lighting device of claim 1, wherein at least one of: a color rendering (Rf1) of the first white light is in the range of 85-100; a color gamut (Rg1) of the first white light is in the range of 102-115; a color rendering (Rf2) of the second white light is in the range of 90-100; a color gamut (Rg2) of the second white light is in the range of 90-100; a color rendering (Rf3) of the third white light is less than 85; and a color gamut (Rg3) of the third white light is less than 100.
8. The lighting device of claim 1, wherein at least one of: with respect to the first light source, the at least one of the oversaturated color spectrum and color gamut is prioritized over other characteristics such that the first white light is characterizable as attractive to the user; and with respect to the second light source, the at least one of color rendering and color fidelity is prioritized over other characteristics such that the second white light is characterizable as natural to the user.
9. The lighting device of claim 1, wherein the control electronics are configured to control the first light source, the second light source, and the third light source in such a way that a maximum of two of those three light sources is activated simultaneously.
10. The lighting device of claim 1, wherein the first white light, the second white light, and the third white light form corner points of a target area for the resultant mixed white light in the spectral parameter space.
11. The lighting device of claim 10, wherein the control electronics are configured to control the first light source, the second light source, and the third light source in such a way that a point corresponding to the resultant mixed white light describes an adjustable or predetermined trajectory within the target area for the resultant mixed white light in the spectral parameter space.
12. The lighting device of claim 1, wherein the control electronics comprise: a processing element; and a memory unit communicatively coupled with the processing element.
13. The lighting device of claim 1, wherein the control electronics are configured to vary a spectral composition of the mixed white light at least one of: in time; and based on user input received by the lighting device.
14. The lighting device of claim 1, wherein at least one of the first light source, the second light source, and the third light source comprises a plurality of light-emitting diodes (LEDs) configured for generating the respective first white light, second white light, or third white light with a predefined color temperature.
15. The lighting device of claim 14, wherein the plurality of LEDs is further configured for generating the respective first white light, second white light, or third white light with a predefined spectral expression.
16. The lighting device of claim 1, further comprising a communication interface configured to provide the lighting device with one or more communication capabilities.
17. The lighting device of claim 1, further comprising a network interface configured to provide the lighting device with one or more network interfacing capabilities.
18. The lighting device of claim 1, wherein the lighting device is a lamp or a luminaire.
19. A system comprising: the lighting device of claim 1; and a display device configured to be communicatively coupled with the lighting device.
20. The system of claim 19, wherein the display device is configured for visualizing a target area for the resultant mixed white light in the spectral parameter space so that a position in the target area corresponding to the resultant mixed white light is controllable by the user via the display device.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The invention is now explained in more detail with the aid of the attached figures. The same reference signs are used in the figures for identical or similarly acting parts.
(2) FIG. 1 shows an Rf-Rg diagram for characterizing white light spectra,
(3) FIG. 2 shows a spectral distribution of a natural white light according to an embodiment example,
(4) FIG. 3 shows a spectral distribution of an attractive white light according to an embodiment example,
(5) FIG. 4 shows a spectral distribution of an efficient white light according to an embodiment example,
(6) FIG. 5 shows a target area defined by three white light sources in a light parameter space according to an embodiment example,
(7) FIG. 6 shows a light design space according to an embodiment example,
(8) FIG. 7 shows a light design space according to a further embodiment,
(9) FIG. 8 shows a light design space according to another embodiment,
(10) FIG. 9 shows a light design space according to a further embodiment,
(11) FIG. 10 shows a light design space according to another embodiment,
(12) FIG. 11 shows a light design space according to a further embodiment,
(13) FIG. 12 shows a light design space according to another embodiment,
(14) FIG. 13 shows a dynamic white light curve according to an embodiment example within the light design space according to FIG. 8,
(15) FIG. 14 shows a user interface of the lighting device according to an embodiment, and
(16) FIG. 15 schematically shows a lighting device for generating a white mixed light according to an embodiment example.
DETAILED DESCRIPTION
(17) FIG. 1 shows an Rf-Rg diagram for characterizing white light spectra according to an example. In the Rf-Rg metric shown in FIG. 1, the color rendering or color rendering index Rf and the color gamut or color gamut index Rg according to the international standard TM30 are used to characterise white light spectra. The color rendering index Rf is plotted on the x-axis in FIG. 1, and the color gamut Rg is plotted on the y-axis. Each white light with a certain color rendering and with a certain color gamut can be assigned a point in the Rf-Rg diagram shown in FIG. 1. The three points 1, 2, and 3 shown in FIG. 1 thus correspond to three different white light sources with different spectral characteristics.
(18) The Rf-Rg diagram shown in FIG. 1 is divided into several zones. The shaded triangular zones in the upper right area and in the lower right area illustrate the so-called forbidden zones, which are practically unreachable according to the definition of the TM30 metric. Furthermore, the Rf-Rg diagram shows a first zone 4 delimited by a dashed line, in which the first point 1 corresponding to a first white light source is located. The first zone 4 is characterized by relatively high values of the color rendering Rf and by high values of the color gamut Rg. In the embodiment example shown, the first zone 4 lies in the parameter range 85<Rf<100 or 102<Rg<115. The first zone 4 thus defines a parameter range for white lights with oversaturated colors or high gamut and with relatively good color rendering. Such white light is often perceived as particularly attractive. The first zone 4 thus corresponds to the parameter range of an attractive white light. White light corresponding to point 1 can thus also be described as attractive light.
(19) The Rf-Rg diagram also shows a second zone 5 delimited by a dashed line, in which the second point 2 corresponding to a second white light source is located. The second zone 5 is characterized by high values of the color rendering Rf and by relatively low values of the color gamut Rg. In the embodiment example shown, the second zone 5 lies in the parameter range 90<Rf<100 or 90<Rg<98. Due to the high color rendering or color fidelity, the white light corresponding to the second point 2 can also be referred to as natural light.
(20) The Rf-Rg diagram also shows a third zone 6 delimited by a dashed line, in which the third point 3 corresponding to a third white light source is located. The third zone 6 is characterized by low values of the color rendering Rf as well as low values of the color gamut Rg. In the embodiment example shown, the third zone 6 lies in the parameter range 80<Rf<85 or 80<Rg<98.
(21) A white light to be assigned to the third zone can, in particular, be generated by a white light source which is designed to generate white light in a particularly energy-efficient manner, in particular, by accepting a deterioration of the attractiveness or naturalness of the light. For example, the spectral characteristics of the light source can be selected in such a way that maximum energy efficiency is achieved, if necessary with minimum color rendering and minimum gamut. Such light is also referred to as efficient light in the following.
(22) FIG. 2 shows a spectral distribution of a natural white light according to an embodiment example. In particular, FIG. 2 shows the spectral distribution of the natural white light in comparison to a reference light (shown in rectified form). The spectrum of the reference light corresponds essentially to the spectrum of the black body radiation. As can be seen in FIG. 2, the spectral curve of the natural light largely follows the spectral curve of the reference light. The color rendering Rf and the color gamut Rg of the natural light are approximately 100.
(23) FIG. 3 shows a spectral distribution of an attractive white light according to an embodiment example. The color spectrum shown in FIG. 3 differs from the color spectrum of FIG. 2, in particular, by a higher weighting of the spectrum in the red and in the green spectral range and by an underweighting of the spectrum in the yellow spectral range at wavelengths of about 580 nm. The spectrum shown in FIG. 3 corresponds to a gamut Rg of 105 and is perceived as particularly attractive by people due to the slight oversaturation of color.
(24) FIG. 4 shows a spectral distribution of an efficient white light according to an example. The color spectrum shown in FIG. 4 differs from the color spectrum of FIG. 2, in particular, by an overweighting of the spectrum in the yellow-orange-amber-yellow color range at wavelengths of about 580 to 615 nm and by an underweighting of the spectrum in the red spectral range at wavelengths of about 620 to 650 nm and in the green spectral range at wavelengths of 510 to 530 nm. The spectrum shown in FIG. 4 corresponds to an efficient light with color rendering Rf of 85. Such white light can be generated in a particularly energy-efficient manner, especially by means of LED light sources.
(25) FIG. 5 shows a target area defined by three white light sources in a light parameter space according to an embodiment example. In the light parameter space of FIG. 5, color rendering Rf and color gamut Rg as well as color temperature (CCT) are plotted as parameters on the coordinate axes. FIG. 5 shows three points in the Rf-Rg plane. Similar to FIG. 1, these three points correspond to an attractive light, a natural light, and an efficient light. Therefore, these three points are indicated by ATTRACTIVE, NATURAL, and EFFICIENT in FIG. 5. In this embodiment example, the three white lights have the same color temperature. When these white light sources are used in a lighting device to produce a white mixed light, the resulting white mixed light will also have the same color temperature. The point corresponding to the resulting mixed light will thus also lie in the Rf-Rg plane, within the triangle defined by the three points 1, 2, and 3. By changing the proportional contributions of the respective white light sources, for example, by the control electronics of the lighting device, the position in the light parameter space corresponding to the mixed light within the triangle can be varied. Consequently, the three white lights ATTRACTIVE, NATURAL, and EFFICIENT define a triangular target area or design space in the lighting parameter space, in which the user or lighting designer can realize different lighting recipes or spectral compositions for the white mixed light.
(26) FIG. 6 shows a light design space according to an example. The light design space shown can be realized by the three white light sources according to FIG. 5. In this case, the light design space is limited to the perimeter of the triangle of FIG. 5, which is illustrated by bold lines in FIG. 6. This design space corresponds to an operating mode of the lighting device when a maximum of two of the three white light sources are activated simultaneously, so that a maximum of two of the three white lights are represented in the white mixed light. By excluding one of the three white lights, the adjustment of the spectral characteristics of the resulting white light can be simplified for the user.
(27) FIG. 7 shows a lighting design space according to a further example. In this embodiment, the design space corresponds to the entire target area, which is defined by the triangle spanned on the three corner points. In particular, the control electronics can be configured such that the position within the triangle corresponding to the resulting mixed light can be varied as desired. In this case, the user can realize more complicated recipes or finer mixtures of the attractive, natural, and efficient lights.
(28) FIG. 8 shows a light design space according to another design example. The light design space shown in FIG. 8 is realized by six white light sources, wherein three additional white light sources with a higher color temperature have been added to the three white light sources of FIG. 5. The lights generated by the three additional white light sources are also represented as points in the light parameter space, which lie in a plane parallel to the Rf-Rg plane at a higher CCT. In terms of attractiveness, naturalness, and efficiency, the three additional white light sources correspond to the three white light sources of FIG. 5, so that the projection of the corresponding points 1, 2, and 3 on the Rf-RG planes correspond to points 1, 2, and 3. White light with a higher color temperature usually has an activating effect on the human body. This is why points 1, 2, and 3 in FIG. 8 are marked ACTIVATING. The six white light sources thus provide a three-dimensional target area in the form of a triangular prism for positioning the resulting white light point in the light parameter space. The user or lighting designer can adjust the spectral properties of the resulting light in terms of attractiveness, naturalness, efficiency, and activating effect within the triangular prism according to his preferences, if necessary depending on the situation. For example, by increasing the proportional intensity of the white light sources with the higher color temperature, the user can move the resulting white point upwards to the white points 1, 2, or 3 to increase the activating effect of the resulting white light.
(29) FIG. 9 shows a light design space according to a further example. The light design space of FIG. 9 is substantially the same as the light design space of FIG. 8, wherein the attractiveness, naturalness, and efficiency of the white light points 1, 2, and 3 do not match the attractiveness, naturalness, and efficiency of the white light points 1, 2, and 3. In particular, the projection of the triangle formed by the white points 1, 2, and 3 on the Rf-Rg plane does not coincide with the triangle formed by the white points 1, 2, and 3. This example is intended to illustrate in particular that the light design space can in principle also have a curved or twisted shape, depending on the design.
(30) FIG. 10 shows a light design space according to another embodiment. In this example, four white light sources are used, which are represented by corresponding white light points in the light parameter space. The light design space of FIG. 10 is substantially the same as the light design space of FIG. 9, wherein instead of the second group of white light sources, only a single white light source with the higher color temperature is used as the fourth white light source. The corresponding white point 10 together with the first three white points 1, 2, and 3 forms a target area or light design space in the form of a, possibly oblique, pyramid in the light parameter space, in which the user or light designer can position the white point as required. For example, by increasing the proportional intensity of the fourth light, the user can shift the resulting white point upwards or towards white point 10 to increase the activating effect of the resulting mixed light.
(31) FIG. 11 shows a light design space according to a further embodiment example. In this example, the light design space is defined by two white light sources of the first group with corresponding white points 2 and 3 at the lower color temperature and by two white light sources of the second group with corresponding white points 2 and 3 at a higher color temperature. The white points 2, 3, 2, and 3 thus define a rectangular area as the lighting design space or target area. In the embodiment shown, only attractive and efficient white light sources are used. In other embodiments, other combinations of white light sources, for example, natural and efficient or natural and attractive, are used depending on the user's preferences.
(32) FIG. 12 shows a light design space according to another embodiment. In this embodiment, the light design space is defined by two white light sources of the first group with corresponding white points 2 and 3 at the lower color temperature and by one white light source of the second group with corresponding white points 20 at the higher color temperature. The white points 2, 3, and 20 thus define a two-dimensional triangular area as the light design space or target area. The light design space according to FIG. 12 can be provided in a relatively simple manner using three white light sources. In the example shown, the main focus is on efficiency and attractiveness or activating effect of the light, but other combinations of white light sources are also possible, depending on the user's preferences.
(33) FIG. 13 shows a dynamic white light curve according to an embodiment within the light design space according to FIG. 8. The dynamic white light curve 40 is shown as a solid line extending between a first end near white point 1 at the lower color temperature and a second end near white point 2 at the higher color temperature. The dynamic white curve 40 describes the trajectory in the light parameter space through which the target point or the position of the white point corresponding to the resulting mixed light passes in the course of the day in the target area. In FIG. 13, times of day are also indicated to illustrate that the target point in the morning at 6:00 a.m. starts approximately at the white point 2, which corresponds to an attractive white light with an activating effect. Such a light can provide both rapid activation and a positive mood after waking up. During the day, especially between 11:00 and 16:00, the dynamic white light curve 40 runs mainly along the longitudinal edge of the triangular prism between the white points 3 and 3, corresponding to an efficient light with gradually decreasing color temperature. In the evening around 9:00 p.m., the curve ends near white point 1 in the Rf-Rg plane at the low color temperature, which corresponds to a cosy natural light. The dynamic white light curve 40 of FIG. 14 thus enables the user to start the day with an attractive activating light and to end the day with a natural warm light, wherein electrical energy is saved during the day.
(34) FIG. 14 shows a user interface of the lighting device according to an embodiment example. In this embodiment, the user interface 50 has a display device 60 in the form of a touchscreen. The user interface 50 can be implemented, in particular, on a smart phone, tablet PC, or the like with a corresponding application software or app. The user interface 50 is designed to display an image 80 of the target area as well as an image 90 of the target point or the white light point corresponding to the white mixed light to be generated. In FIG. 14, a triangular target area according to the embodiment of FIG. 5 is shown as an example. Target areas in the form of a triangular prism or other form can also be visualized in principle by means of the display device 60.
(35) FIG. 15 schematically shows a lighting device for generating a white mixed light according to an embodiment example. The lighting device 100 comprises a number of white light sources 150. In this embodiment example, the white light sources 150 are designed as LED light sources. The LED light sources may each have an LED combination for generating a respective white light with a respective spectral expression that can be quantitatively characterized. The LEDs of different white light sources may, in particular, be mounted on a common circuit board or separately. The lighting device 100 further comprises mixing optics 200 for mixing the lights generated by the white light sources 150 to form a resulting white mixed light 250. The resulting white mixed light is shown schematically as a broad arrow in FIG. 15.
(36) The lighting device 100 further comprises control electronics 300 for controlling the white light sources 150 so that the proportional contributions of the white lights produced by the white light sources 150 to the resulting mixed light 250 can be varied. The lighting device 100 further comprises driver electronics (not shown) for driving the white light sources 150. The driver electronics may be formed as part of the control electronics 300 or also as separate units. The control electronics 300 comprise a memory unit (not shown) and a processor (not shown). The memory unit may, in particular, contain machine-readable instructions for the processor to control the driver electronics.
(37) The illuminating device 100 further comprises a user interface 50, which is connected to the control electronics 200 of the illuminating device 100 via corresponding communication interfaces (not shown). The communication interfaces may be configured for wired and/or wireless communication between the control electronics 300 and the user interface 50. In some embodiments, the user interface 50 is similar to the user interface shown in FIG. 14.
(38) By changing the number as well as the spectral characteristics of the white light sources 150, different target areas in the light parameter space can be shaped to realise different light recipes and displayed on the display device 60 of the user interface 50.
(39) During operation of the lighting device 100, the user can position the target point of the white light to be generated in the target area in any desired way by means of the display device 60 of the user interface 50 in order to compose the desired mixed light composition or light recipe. Due to the visual representation of the target area as well as the target point in the target area on the display device, the operation of the lighting device 100 can be largely intuitive. The settings selected by the user can, then, be transmitted to the control electronics 300 via the communication interfaces, so that the proportional contributions of the white light sources 150 to create the desired mixed light can be adjusted accordingly. The user can, thus, adjust the desired spectral characteristics of the resulting light in a simple and convenient manner.
(40) The lighting device 100 may be a lamp or a luminaire. In some embodiments, the lighting device 100 comprises a network interface. The network interface may, in particular, be designed to communicate with the user interface 50 and/or with a central control unit via a standard protocol such as DALI?, Wi-Fi?, Zigbee?, Bluetooth?, or the like, either wired or wireless. In particular, the communication interface may be used to transmit instructions to the control electronics 300 for modifying the lighting recipes. The communication interface may also be adapted to communicate with other network participants to form lighting networks.
(41) By means of the lighting device described above, basically all essential requirements for lighting designers in the area of general lighting can be covered. By using the white light sources, the mixed light also becomes white, even if the proportional contributions of individual white light sources are not exactly maintained.
(42) The light recipes or the corresponding areas in the light parameter space can be pre-set for individual lighting devices as well as for entire product classes of lighting devices by configuring or programming the control electronics. Furthermore, the light recipes can be varied in time as required. In particular, the spectral composition of the mixed light produced by the lighting device can be varied according to the time of day using dynamic light recipes. In addition, the user can flexibly and conveniently vary the light recipes as required, for example, depending on the application or mood, via the user interface.
(43) Although at least one exemplary embodiment has been shown in the foregoing description, various changes and modifications may be made. The aforementioned embodiments are examples only and are not intended to limit the scope, applicability or configuration of the present disclosure in any way. Rather, the foregoing description provides the person skilled in the art with a plan for implementing at least one exemplary embodiment, wherein numerous changes in the function and arrangement of elements described in an exemplary embodiment may be made without departing from the scope of protection of the appended claims and their legal equivalents. Furthermore, according to the principles described herein, several modules or several products can also be connected with each other in order to obtain further functions.
LIST OF REFERENCE SIGNS
(44) 1, 1 white light point 2, 2 white light point 3, 3 white light point 4 first zone 5 second zone 6 third zone 10 white light point 20 white light point 40 dynamic white light curve 50 user interface 60 display device 80 display of the target area 90 display of the target point 100 lighting device 150 white light source 200 mixed optics 250 mixed light 300 control electronics CCT color temperature CCT1 first color temperature CCT2 second color temperature Rf color rendering Rg color gamut CCT color temperature
