High-fidelity low-blue light system

Abstract

A lighting system for emitting emitted light includes: (a) several independently controlled channels, each channel representing a point in a color space diagram, the several channels including at least: (i) a blue channel with a blue point in the color space diagram; (ii) a cyan channel with a cyan point in the color space diagram; (iii) a red channel with a red point in the color space diagram; and (iv) a violet-pumped low-blue channel with a low-blue point in the color space diagram, the low-blue point lying within a 7-step MacAdam ellipse on the blackbody curve; and (b) a controller for independently controlling each of the multiple channels to vary the emitted light.

Description

Cross-reference to related registrations

[0001] The present patent application claims priority from US Provisional Application 63 / 434,320, filed on December 21, 2022, the entirety of which is hereby incorporated by reference. Field of invention

[0002] The present invention relates generally to high-fidelity lighting (i.e., with high fidelity reproduction), and in particular to high-fidelity lighting with a mode for minimizing circadian stimulation. State of the art

[0003] A wide variety of light-emitting devices are known in the prior art, including, for example, incandescent bulbs, fluorescent lamps, and semiconductor light-emitting devices such as light-emitting diodes (“LEDs”). LEDs with high light quality are of particular interest.

[0004] The quality of light can be described in various ways. For example, one commonly used resource is the 1931 CIE (Commission Internationale de l'Éclairage) color space diagram. The 1931 CIE color space diagram maps human color perception using two parameters, x and y. The spectral colors are distributed around the edge of the enclosed space, which includes all hues perceptible to the human eye. The boundary line represents maximum color saturation for the spectral colors, and the inner region represents less saturated colors, including white. The diagram also shows the Planck locus, also known as the blackbody locus (BBL), with correlated color temperatures, which represent the chromaticity coordinates (i.e., color points) corresponding to the radiation emitted by a blackbody at different temperatures.Lighting devices that produce light at or near the BBL (Brightness Baseline) can therefore be described by their correlated color temperature (CCT). These lighting devices produce pleasant "white light" for human viewers, with general lighting typically using CCT values ​​between 1,800 K and 10,000 K.

[0005] The color rendering index (CRI) describes the vividness of the colors of light produced by a light source. In practical terms, the CRI is a relative measure of the shift in the surface color of an object when illuminated by a particular lamp, compared to a reference light source, typically either a blackbody radiator or the daylight spectrum. The higher the CRI value for a given light source, the better that light source renders the colors of the various objects it illuminates.

[0006] Color rendering performance can be assessed using standard metrics known in the field. The fidelity index (Rf) and the gamut index (Rg) can be calculated based on the color rendering of a light source for 99 color evaluation samples (CES). The 99 CES provide uniform color gamut coverage, are intended to be neutral with respect to spectral sensitivity, and offer color samples corresponding to a wide variety of real-world objects. Rf values ​​range from 0 to 100 and indicate the (color) fidelity with which a light source renders colors compared to a reference illuminant. In practical terms, the Rf is a relative measure of the shift in the surface color of an object when illuminated by a particular lamp, compared to a reference light source, typically either a blackbody radiator or the daylight spectrum.The higher the Rf value for a particular light source, the better the light source renders the colors of the various objects it illuminates. The Gamut Index Rg assesses how well a light source saturates or desaturates the 99 CES compared to the reference source.

[0007] The applicant previously disclosed a revolutionary LED lighting system that provides white light on the blackbody curve with a very high Rf over a wide CCT range – e.g., from 1,800 K to 10,000 K. See, e.g., PCT / US2018 / 020787. In one embodiment, the system has a blue channel, a red channel, a short-wavelength blue-cyan channel (green), and a long-wavelength blue-cyan channel (cyan). Although this system provides unsurpassed light quality and tunability in an LED lighting system, the applicant acknowledges the need to reduce circadian stimulation (CS). In particular, due to the long-wavelength blue-cyan channel, the emitted light ranges from normal to high CS and can thus result in undesirable CS.

[0008] Furthermore, blue light in particular inhibits melatonin production and can negatively affect the natural sleep cycle of the human body. As used herein, the term "circadian-stimulating energy characteristic" refers to any characteristic of a spectral power distribution that can have biological effects on an individual. Circadian-stimulating energy characteristics can be described in various ways, including, for example, circadian-stimulating energy (CSE), circadian stimulation (CS), equivalent melanopic lux (EML), and M / P ratio. Of particular interest here are EML and the M / P ratio. EML represents a measure of photoreceptive input for the circadian and neurophysiological light response in humans. The M / P ratio compares the melanopic (ipRGC) potential with the light source's ability to produce light sufficient for daylight detail perception (photopic vision).

[0009] The applicant acknowledges the need for LED lamps that provide high-quality white light over a range of CCT values ​​while simultaneously moderating CS. The present invention fulfills, among other things, these requirements. Brief description of the invention

[0010] The following is a simplified summary of the invention to provide a basic understanding of some aspects of it. This summary is not a comprehensive overview of the invention. It is not intended to identify critical / key elements of the invention or to define its scope. Its sole purpose is to present some concepts of the invention in a simplified form, as an introduction to the more detailed description presented later.

[0011] As mentioned above, the lighting system disclosed in PCT / US2018 / 020787 is a revolutionary LED lighting system that provides white light on the blackbody curve with a very high Rf over a wide CCT range – e.g., from 1,800 K to 10,000 K. In one embodiment, the system features a blue channel, a red channel, a short-wavelength blue-cyan channel (green), and a long-wavelength blue-cyan channel (cyan). Although this system provides unsurpassed light quality and tunability in an LED lighting system, the applicant acknowledges the need to reduce EML. In particular, due to the long-wavelength blue-cyan channel, the emitted light ranges from typical EML (for commercially available LEDs) to high EML, and can thus result in undesirable CS.

[0012] Accordingly, the applicant discloses herein the introduction of a low-blue channel. In particular, in one embodiment, the applicant replaces the high-EML short-wavelength blue-cyan channel with a violet-pumped low-blue channel. The combination of the long-wavelength blue-cyan channel with the low-blue channel provides an alternative to the short-wavelength blue-cyan (green) channel. Such a light system offers various modes, including a high-circadian stimulating mode (using the long-wavelength blue-cyan channel), a low-circadian stimulating mode (using the low-blue channel), and a high-fidelity channel (using both the long-wavelength blue-cyan and the low-blue channels), without sacrificing light quality.Furthermore, the applicant specifically expected a loss of Rf in high-fidelity mode because the light from the low-blue channel—which has a relatively low Rf—would be needed to fill the gap previously filled by the short-wavelength blue-cyan channel. However, this did not occur. Instead, the applicant unexpectedly found that high-fidelity mode performed almost as well with the low-blue channel as it had with the short-wavelength blue-cyan channel.

[0013] In a particular embodiment, the low-blue channel is located close to or on the blackbody curve, such that, in low-EML mode, the light emitted by the red, low-blue, and blue channels is close to the blackbody curve and requires only a minimal contribution, if any, from the cyan channel to pull the light onto or slightly above the blackbody curve. Although the applicant expected the Rf values ​​in the emitted light to decrease due to the reduction in light in the 440-490 range, the resulting Rf values ​​were very good. Therefore, the invention includes, among other things, the unexpectedly robust contribution of the low-blue channel to the high-fidelity mode, thereby minimizing the reduction in Rf.

[0014] In one embodiment, the invention relates to an illumination system for emitting emitted light, comprising: (a) several independently controlled channels, each channel representing a point in a color space diagram, the several channels comprising at least: (i) a blue channel with a blue point in the color space diagram; (ii) a cyan channel with a cyan point in the color space diagram; (iii) a red channel with a red point in the color space diagram; and (iv) a violet-pumped low-blue channel with a low-blue point in the color space diagram, the low-blue point being located within a 7-step MacAdam ellipse on the blackbody curve; and (b) a controller for independently controlling each of the several channels to vary the emitted light. Brief description of the drawings Fig. Figure 1 shows an embodiment of the lighting system of the present invention. Fig. Figure 2A shows the spectral power distribution (SPD) for each channel of an embodiment of the lighting system of the present invention. Fig. Figure 2B shows a color diagram of an embodiment of the lighting system of the present invention. Fig. Figure 3A shows the Rf values ​​over a wide CCT range for three different modes of an embodiment of the lighting system of the present invention. Fig. Figure 3B shows the M / P ratios over a wide CCT range for three different modes of an embodiment of the lighting system of the present invention. Fig. Figure 4A is a color diagram showing a region of the blue channel of an embodiment of the lighting system of the present invention. Fig. Figure 4B is a color diagram showing regions of the cyan and red channels of an embodiment of the lighting system of the present invention. Fig. Figure 5 is a color diagram showing particular regions of the cyan and red channels of an embodiment of the lighting system of the present invention. Fig. Figure 6 is a color diagram showing other regions of the cyan and red channels of an embodiment of the lighting system of the present invention. Fig. Figure 7 is a color diagram showing particular regions of the blue and red channels of an embodiment of the lighting system of the present invention. Fig. Figure 8 is a color diagram showing particular regions of the blue and red channels of an embodiment of the lighting system of the present invention. Fig. Figure 9 is a color diagram showing particular regions of the red channel of an embodiment of the lighting system of the present invention. Fig. Figure 10 is a color diagram showing particular regions of the blue channel of an embodiment of the lighting system of the present invention. Fig. Figure 11A is a color diagram showing a region of the low-blue channel of an embodiment of the lighting system of the present invention. Fig. Figure 11B is a color diagram showing a very special region of the low-blue channel of an embodiment of the lighting system of the present invention. Description of the embodiments

[0015] In this description, the preferred embodiment and the examples shown should be understood throughout as illustrative, rather than as limitations of the present invention. As used herein, the “present invention” relates to any embodiment of the invention described herein and any equivalents. Furthermore, reference to various features of the “present invention” throughout this document does not imply that all claimed embodiments or methods must necessarily possess the referenced feature.

[0016] Referring to Fig. Figure 1 shows an embodiment of the lighting system 100 of the present invention. The system comprises several independently controlled channels, each channel representing a point in a color space diagram. The several channels include at least one blue channel 101 with a blue point 201 in which the Fig. The color space diagram 200 shown in Figure 2B includes a cyan channel 102 with a cyan point 202 in the color space diagram, a red channel 103 with a red point 203 in the color space diagram, and a violet-pumped low-blue channel 104 with a low-blue point 204 in the color space diagram, the low-blue point lying within a 7-step MacAdam ellipse on the blackbody curve. The system also includes a controller 110 for independently controlling each of the multiple channels to vary the emitted light from the lighting system. Modes

[0017] The configuration of these four channels allows the lighting system of the present invention to operate in at least three modes over a wide CCT range. In particular, in one embodiment, the controller is configured to operate the lighting system to emit light in a low-EML mode, a high-EML mode, and a high-fidelity mode. In the low-EML mode, mainly the blue, red, and low-blue channels are driven, while the current to the cyan channel is reduced or eliminated entirely. In the high-EML mode, mainly the blue, red, and cyan channels are driven, while the current to the low-blue channel is reduced or eliminated entirely. In the high-fidelity mode, all four channels are driven across the CCT range to emit light with the highest RF values. In one embodiment, the controller drives different channels with varying intensities in the different modes.Referring to Table 1, the relative power of each channel for each mode across the CCT range is given. In one embodiment, the relative contribution for each channel in each mode is within ±20%, or within ±10%, or within ±5% of the values ​​given in Table 1. High-fidelity mode

[0018] As described above, the applicant unexpectedly discovered that the lighting system of the present invention is capable of emitting light that exhibits a fidelity (e.g., Rf) close to that of the high-fidelity system disclosed in PCT / US2018 / 020787. For example, with reference to Fig. 3A the fidelity of reproduction of the different modes of the system's embodiment with the in Fig. The channels described in Figure 2A are shown. In particular, the drawing shows the Rf values ​​of the low-EML mode 301, the high-EML mode 302, and the high-fidelity mode 303 as a function of the CCT. It is noteworthy that the high-fidelity mode achieves Rf values ​​greater than 90 over a wide CCT range. In one embodiment, when in high-fidelity mode, the emitted light has an Rf value of at least 90 between 2,000 K and 80,000 K or between 1,800 K and 10,000 K, or at least 95 between 2,500 K and 7,000 K, or at least 97 at 4,000 K. Even the high-EML and low-EML modes exhibit relatively high Rf values. For example, in one embodiment, the Rf value for the emitted light is at least 80 above 4,000K or between 4,000K and 10,000K, or at least 85 above 5,000K or between 5,000K and 10,000K, regardless of the mode. Low EML mode

[0019] As discussed above, a key aspect of the present invention is a lighting system with a low-EML mode. In one embodiment, the low-EML mode reduces blue light in the emitted light. In one embodiment, the emitted light has a total SPD power and a blue-light SPD power between 440 nm and 490 nm, wherein the blue SPD power is not greater than 5%, 3%, 2%, or 1% of the total SPD power. Instead of blue light, in one embodiment, the present invention compensates for the blue light with violet light. In one embodiment, the emitted light has a total SPD power and a violet SPD power between 380 nm and 420 nm, wherein the violet SPD power is at least 2%, 3%, 4%, or 5% of the total SPD power.

[0020] Reducing the blue component of light has a positive effect on reduced circadian stimulation. For example, with reference to Fig. 3B, the circadian effects of the different modes of the system's embodiment with the in Fig. The channels described in section 2A are shown. In particular, the M / P ratios for the low-EML mode 311, the high-EML mode 312, and a high-fidelity mode 313 are shown. In the low-EML mode 311, the M / P ratio is not greater than 1 below 6,000 K, or not greater than 0.8 below 4,000 K, or not greater than 0.6 below 3,000 K. High EML mode

[0021] In one embodiment, the lighting system of the present disclosure also features a high-EML mode. Again, with reference to Fig. 3B, the M / P ratio in high-EML mode 311 is not less than 0.8 above 4,000K, and not less than 1 above 5,000K. Channel design forms

[0022] Referring to Fig. Figure 2A shows the SPDs of each of the four channels of an embodiment of the present invention. In particular, it shows Fig. 2A the SPD profiles for the blue channel 221, the cyan channel 222, the red channel 223 and the low-blue channel 224. In one embodiment, the SPD of each channel lies within + / -20% or within + / -10% or within + / -5% of the specified value. Fig. SPD shown in 2A.

[0023] Fig. 2B shows a color diagram 200 for the in Fig. 2A shows the four-channel version. In particular, it shows Fig. 4B defines the color gamut (gamut) 210 of the four-channel system defined by the blue point 201, the cyan point 202, the red point 203, and the low-blue point 204. It is noteworthy that essentially the entire BBL 230 lies within the color gamut 210 over a wide CCT range. The daylight spectrum 231 also lies within the color gamut 210. Low blue channel

[0024] The low-blue channel is located on or near the BBL and is pumped with a violet, ultraviolet, or near-ultraviolet LED. Replacing the low-blue channel with the short-wavelength blue-cyan channel of PCT / US2018 / 020787 represents a significant innovation that facilitates a low-EML mode while still providing high fidelity in high-fidelity mode.

[0025] In one embodiment, the low-blue point lies within region 1101 as in the 1931 CIE color chart. Fig. 11A is shown. In particular, region 1101 is bounded by the equi-CCT lines of 1,800 K and 4,500 K and the spectral locus. In a Fig. In the further special embodiment shown in Figure 11B, region 1102 is bounded by equi-CCT lines of 3220K and 2580K, and Duv = + / - 6 points between 3220 and 2580K. Alternatively, region 1102 can be defined by the area with the following ccx, ccy color coordinates: [0,4147, 0,3814]; [0,4593, 0,3944]; [0,4813, 0,4319], and [0,4299, 0,4165].

[0026] The low-blue channel has a relatively small blue component. In one embodiment, the low-blue channel emits low-blue light with a total low-blue SPD power and a blue light power between 440 nm and 490 nm, where the blue light power is less than 2% of the total low-blue SPD power. For example, in one embodiment, the blue SPD power is 1.32% of the total low-blue SPD power at 2700 K, or the blue SPD power is approximately 1.69% of the total low-blue SPD power at 3000 K.

[0027] As is known, to use LEDs to generate white light, one or more luminescent materials such as phosphors or quantum dots are used to convert some of the light emitted by one or more LEDs into light of one or more colors. Combining the light emitted by the LEDs that was not converted by the luminescent materials with light of other colors emitted by the luminescent materials can produce white or near-white light. In one embodiment, the LED is a violet pump LED. In one embodiment, the violet pump LED has a peak wavelength of 380 to 430 nm, or 390 to 420 nm, or 395 to 420 nm, or 400 to 420 nm, or 405 to 410 nm.

[0028] In one embodiment, the low-blue channel emits low-blue light that is no larger than a 7-step MacAdam ellipse from the BBL, or no larger than a 6-step MacAdam ellipse from the BBL, or no larger than a 5-step MacAdam ellipse from the BBL, or no larger than a 4-step MacAdam ellipse from the BBL, or no larger than a 3-step MacAdam ellipse from the BBL. Blue Channel

[0029] In some embodiments of the present disclosure, lighting systems may include blue channels that produce light with a blue color spot falling within a blue color range. In certain embodiments, suitable blue color ranges may include the blue color ranges 301A-F. Fig. 4A shows a blue color area 301A bounded by a line connecting the ccx, ccy color coordinates of the infinity point of the blackbody curve (0.242, 0.24) and (0.12, 0.068), the Planck locus of 4000K and infinity CCT, the constant CCT line of 4000K, the purple line, and the spectral locus. Fig. 4A also shows a blue color region 301D, bounded by a line connecting (0.3806, 0.3768) and (0.0445, 0.3), as well as the spectral locus between the monochromatic point of 490 nm and (0.12, 0.068), a line that defines the ccx and ccy color coordinates of the infinity point of the blackbody curve (0.242, 0.24) and (0.12, 0.068), and the Planck locus of 4000 K and infinity CCT. The blue color region could also be the combination of regions 301A and 301D. Fig. Figure 7 shows a blue color range 301B bounded by a 60-step MacAdam ellipse at a CCT of 20,000K, 40 points below the blackbody curve. Fig. Figure 8 shows a blue color area 301C bounded by a polygonal region in the 1931 CIE color diagram, which is bounded by the following ccx, ccy color coordinates: (0,22, 0,14), (0,19, 0,17), (0,26, 0,26), (0,28, 0,23). Fig. Figure 10 shows blue color ranges 301E and 301F. The blue color range 301E is bounded by lines connecting (0,231, 0,218), (0,265, 0,260), (0,2405, 0,305), and (0,207, 0,256). Cyan channel

[0030] In some embodiments of the present disclosure, lighting systems may include long-wavelength blue-pumped cyan channels that produce light with a cyan color spot falling within a cyan color range. In certain embodiments, suitable cyan color ranges may include cyan color ranges 303A-E. Fig. 4B shows a cyan color area 303A, bounded by a line connecting the ccx, ccy color coordinates (0,18, 0,55), and (0,27, 0,72), the constant CCT line of 9,000K, the Planck locus between 9,000K and 1,800K, the constant CCT line of 1,800K and the spectral locus. Fig. Figure 5 shows some suitable color ranges for some embodiments of the disclosure. A cyan color range 303B can be bounded by the region enclosed by lines connecting (0,360, 0,495), (0,371, 0,518), (0,388, 0,522) and (0,377, 0,499). Fig. Figure 6 shows some further color ranges suitable for some embodiments of the disclosure. A cyan color range 303C is bounded by the line connecting the ccx, ccy coordinates (0,18, 0,55) and (0,27, 0,72), the constant CCT line of 9000K, the Planck locus between 9000K and 4600K, the constant CCT line of 4600K, and the spectral locus. A cyan color range 303D is bounded by the constant CCT line of 4600K, the spectral locus, the constant CCT line of 1800K, and the Planck locus between 4600K and 1800K. In some embodiments, the long-wavelength blue-pumped cyan channel can provide a color point within a cyan color region 303E bounded by lines connecting (0.497, 0.469), (0.508, 0.484), (0.524, 0.472) and (0.513, 0.459). Red Channel

[0031] In some embodiments of the present disclosure, lighting systems may include red channels that produce light with a red color spot falling within a red color range. In certain embodiments, suitable red color ranges may include the red color ranges 302A-D. Fig. 4B shows a red color range 302A, which is bounded by the spectral locus between the constant CCT line of 1600K and the purple line, the purple line, a line connecting the ccx, ccy color coordinates (0.61, 0.21) and (0.47, 0.28) and the constant CCT line of 1600K. Fig. Figure 5 shows some suitable color ranges for some embodiments of the disclosure. A red color range 302B can be bounded by a 20-step MacAdam ellipse at a CCT of 1200K, 20 points below the blackbody curve. Fig. Figure 6 shows some further color ranges suitable for some embodiments of the disclosure. A red color range 302C is defined by a polygonal region in the 1931 CIE color diagram bounded by the following ccx, ccy color coordinates: (0.53, 0.41), (0.59, 0.39), (0.63, 0.29), (0.58, 0.30). Fig. Figure 8 shows a red color area 302C and can be defined by a polygonal region in the 1931 CIE color diagram bounded by the following ccx, ccy color coordinates: (0.53, 0.41), (0.59, 0.39), (0.63, 0.29), (0.58, 0.30). Fig. Figure 9 shows a red color area 302D bounded by lines connecting the ccx, ccy color coordinates (0.576, 0.393), (0.583, 0.400), (0.604, 0.387), and (0.597, 0.380).

[0032] Having thus described a few particular embodiments of the invention, various deviations, modifications, and improvements will be readily apparent to those skilled in the art. Such deviations, modifications, and improvements, which become evident from this disclosure, are to be included in this description, although they are not expressly described herein, and are to be within the concept and scope of the invention. Accordingly, the foregoing description is merely exemplary and not limiting. The invention is limited only to the extent defined in the following claims and equivalents thereto. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 63 / 434,320

[0001] US 2018 / 020787 [0007, 0011, 0018, 0024]

Claims

[1] Lighting system for emitting emitted light, the system comprising: multiple independently controlled channels, each channel representing a point in a color space diagram, the multiple channels including at least: a blue channel with a blue point in the color space diagram; a cyan channel with a cyan point in the color space diagram; a red channel with a red point in the color space diagram; and a violet-pumped low-blue channel with a low-blue point in the color space diagram, the low-blue point lying within a 7-step MacAdam ellipse on the blackbody curve; and A control system for independently controlling each of the multiple channels to vary the emitted light. [2] Lighting system according to claim 1, wherein low-blue light emitted from the low-blue channel lies within a low-blue region in a 1931 CIE colour space diagram, which is bounded by equi-CCT lines at 1800K and 4500K and the spectral locus. [3] Lighting system according to claim 2, wherein the low blue region is limited by equi-CCT lines at 3220K and 2580K, and Duv is between 3220K and 2580K + / -6 points. [4] Lighting system according to claim 2, wherein the low-blue region is bounded by the area between the coordinates [0,4147, 0,3814]; [0,4593, 0,3944]; [0,4813, 0,4319], and [0,4299, 0,4165]. [5] Lighting system according to claim 1, wherein blue light emitted from the blue channel within the Fig. 4B shows regions 301A and 301D. [6] Lighting system according to claim 1, wherein cyan light emitted from the cyan channel within the Fig. Region 303A, shown in 4B, is located there. [7] Lighting system according to claim 1, wherein red light emitted from the red channel within the Fig. Region 302A, shown in 4B, is located there. [8] Lighting system according to claim 1, wherein the controller is configured to control the multiple channels in at least one of a high-fidelity mode, a low-EML mode or a high-EML mode. [9] Lighting system according to claim 1, wherein the relative contribution of each of the channels in each mode is within + / -20%, or within + / -10%, or within + / -5% of the values ​​specified in Table 1. [10] Lighting system according to claim 8, wherein the emitted light in the high-fidelity mode has an Rf of at least 85, or at least 90, or at least 895. [11] Lighting system according to claim 8, wherein the emitted light in the low-EML mode has a total SPD power and a blue light power between 440 nm and 490 nm, wherein the blue light power is not greater than 5%, or 3%, or 2%, or 1% of the total SPD power. [12] Lighting system according to claim 8, wherein the emitted light in the low-EML mode has a total SPD power and a violet light power between 380 nm and 420 nm, wherein the violet light power is at least 2%, or 3%, or 4%, or 5% of the total SPD power. [13] Lighting system according to claim 8, wherein the emitted light in the low-EML mode has an M / P ratio of not more than 1 below 6000K, or not more than 0.8 below 4000K, or not more than 0.6 below 3000K. [14] Lighting system according to claim 8, wherein the emitted light in the high-EML mode has an M / P ratio of not less than 0.8 above 4000K, and not less than 1 above 5000K. [15] Lighting system according to claim 8, wherein the emitted light in each of the modes has an Rf of at least 80.

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