Controller and method for controlling a LED lighting device

Abstract

There is provided a controller (100) and a method (500) for controlling a LED lighting device (110). The controller is configured to, for each LED light source, LEDi, select (140) a color point, CPi (xi, yi), in a color space, CS, of LED light emitted from the LEDi, obtain (150) a light intensity level, Li, of ambient light, AL, and / or emitted gradient device light, determine (160), for the CPi (xi, yi), a distance vector, D (xi, yi), from a white point, P, in the CS to the CPi (xi, yi), determine (170) a shifted distance vector, D' (x'i, y'i), as a function of the Li, and wherein D' (x'i, y'i) = a∙D (xi, yi), determine (180) a shifted color point, CPj (x'i, y'i), in the CS as a function of the D' (x'i, y'i), and control (190) the LEDi to emit LEDi light source light of the CPi (x'i, y'i).

Description

[0001] 2024PF80241

[0002] 1

[0003] CONTROLLER AND METHOD FOR CONTROLLING A LED LIGHTING DEVICE

[0004] FIELD OF THE INVENTION

[0005] The present invention generally relates to a controller and method for controlling a light emitting diode, LED, lighting device. More specifically, the present invention relates to a controller and method for gradient lighting emitted from a LED lighting device.

[0006] BACKGROUND OF THE INVENTION

[0007] The use of light emitting diodes, LEDs, for illumination purposes continues to attract attention. Compared to incandescent lamps, fluorescent lamps, neon tube lamps, etc., LEDs provide numerous advantages such as a longer operational life, a reduced power consumption, and an increased efficiency related to the ratio between light energy and heat energy.

[0008] A particularly attractive lighting effect of LED light sources is gradient lighting, comprising smooth transitions of light and color. Gradient lighting is used creatively in various contexts, for a large range purposes and in many different settings. There is currently a large demand in the market for lighting devices which are able to provide gradient lighting.

[0009] It should be noted that color gradients may be perceived differently for observers or users, e.g. due to one or more conditions in (or of) an environment of the emitted light. However, technologies in the prior art insufficiently address this issue and / or provide devices or methods which are complex and / or inconvenient. Accordingly, there is a wish to even further develop the setting and / or control of the gradient lighting in order to achieve a desired lighting for illumination purposes and / or for an aesthetically appealing lighting effect.

[0010] SUMMARY OF THE INVENTION

[0011] It is of interest to provide gradient lighting via LED light sources, wherein the gradient lighting is compensated / corrected as a function of one or more conditions. By this, a desired lighting is achievable for illumination purposes and / or for an aesthetically appealing2024PF80241

[0012] 2

[0013] lighting effect, whilst benefiting from one or more of the numerous advantages of LED technology.

[0014] This and other objects are achieved by providing a controller and a method for controlling a LED lighting device having the features in the independent claims. Preferred embodiments are defined in the dependent claims.

[0015] According to a first aspect of the present invention, there is provided a controller for controlling a LED lighting device. The LED lighting device is arranged to emit gradient device light, wherein the LED lighting device comprises a plurality of N LED light sources. The controller is configured to, for at least one LED light source, LEDi, of the plurality of N LED light sources, select a color point, CPi (xi, yi), in a color space, CS, of LED light to be emitted from the LEDi, and obtain a light intensity level, Li, of at least one of ambient light, AL, and the emitted gradient device light. The controller is further configured to determine, for the color point, CPi (xi, yi), a distance vector, D (xi, yi), from a white point, P, in the color space, CS, to the color point, CPi (xi, yi), and to determine a shifted distance vector, D’ (x’i, y’i), as a function of the light intensity level, Li. The shifted distance vector fulfils D’ (x’i, y’i) = a-D (xi, yi), with a being a scalar factor. The controller is further configured to determine a shifted color point, CPj (x’i, y’i), in the color space, CS, as a function of the shifted distance vector, D’ (x’i, y’i), and to control the LEDi to emit LEDi light source light of the shifted color point, CPi (x’i, y’i).

[0016] According to a second aspect of the present invention, there is provided a method for controlling a LED lighting device. The LED lighting device is arranged to emit gradient device light, wherein the LED lighting device comprises a plurality of N LED light sources. The method comprises, for at least one LED light source, LEDi, of the plurality of N LED light sources, selecting a color point, CPi (xi, yi), in a color space, CS, of LED light to be emitted from the LEDi, and obtaining a light intensity level, Li, of at least one of ambient light, AL, and the emitted gradient device light. The method further comprises determining, for the color point, CPi (xi, yi), a distance vector, D (xi, yi), from a white point, P, in the color space, CS, to the color point, CPi (xi, yi), and determining a shifted distance vector, D’ (x’i, y’i), as a function of the light intensity level, Li. The shifted distance vector fulfils D’ (x’i, y’i) = a-D (xi, yi), with a being a scalar factor. The method further comprises determining a shifted color point, CPj (x’i, y’i), in the color space, CS, as a function of the shifted distance vector, D’ (x’i, y’i), and controlling the LEDi to emit LEDi light source light of the shifted color point, CPi (x’i, y’i).2024PF80241

[0017] 3

[0018] Thus, the present invention is based on the idea of a controller and method which are able to achieve a shift in color point, CPi (xi, yi), dependently on a light intensity level, Li, of ambient light, AL, and / or emitted gradient device light. In other words, the present invention is based on the idea of a controller and method which propose a correction for color point(s), CPi (xi, yi), of LED light emitted from LED(s) LEDi, of a LED lighting device dependent on a light intensity level, Li, of ambient light, AL, and / or emitted gradient device light. The controller and method of the present invention may hereby conveniently and efficiently correct and / or compensate for a change of color perception of the human eye dependently on the light intensity level, Li.

[0019] The present invention is advantageous in that the correction for color point(s), CPi (xi, yi), may be efficiently performed dependently on the light intensity level, Li, including the cases of an increase or decrease of the light intensity level, Li. It will be appreciated that the color visibility of the human eye decreases with decreasing light intensity level, Li, and accordingly, increases with increasing light intensity level, Li. The controller and method of the present invention advantageously compensates / corrects for the light intensity level, Li, such as an increase or decrease of the light intensity level, Li, in order to provide a desired color perception of a user or observer.

[0020] The present invention is further advantageous in that the controller and method are able to provide a gradient lighting (gradient device light) via the LED lighting device in order to achieve a desired lighting for illumination purposes and / or for an aesthetically appealing lighting effect.

[0021] The present invention is further advantageous in that the numerous advantages of using LED technology may be combined with the illumination and aesthetical properties provided by the LED lighting device via the controller or method.

[0022] According to first aspect of the present invention, there is provided a controller for controlling a LED lighting device. By “controller”, it is here meant any unit, element, device, arrangement, or the like, which is configured or arranged for (a) control purpose(s). The LED lighting device is arranged to emit gradient device light. By “gradient device light”, it is here meant light which comprises numerous colors, and that the light provides a smooth and gradual transition between colors. The LED lighting device comprises a plurality of N LED light sources. Hence, the LED lighting device comprises a number of N LED light sources, wherein (the number (integer)) N, preferably, is at least 3. The controller is configured to perform operations, actions or steps for at least one LED light source, LEDi, of the plurality of N LED light sources. For one or more (e.g. each) of the LED light source(s),2024PF80241

[0023] 4

[0024] LEDi, of the LED lighting device, the controller is configured to select a color point, CPi (xi, yi), in a color space, CS, of LED light to be emitted from the LEDi. The controller is further configured to obtain a light intensity level, Li, of at least one of ambient light, AL, and the emitted gradient device light. Hence, the controller is configured to obtain a light intensity level, Li, of (the) ambient (i.e. surrounding) light, AL, and / or the emitted gradient device light from the LED lighting device. The controller is further configured to determine, for the color point, CPi (xi, yi), a distance vector, D (xi, yi), from a white point, P, in the color space, CS, to the color point, CPi (xi, yi). The “white point, P” may be defined as a (white) point having a correlated color temperature, CCT, in a range of 1800 - 20000 K, preferably 2000 - 6500 K, and preferably a distance to the black body locus, BBL, of at most 12 SDCM, such as < 10 SDCM, and more preferred < 7 SDCM. Hence, for the (each) color point, CPi (xi, yi), the controller is configured to determine a distance vector, D (xi, yi), from a white point, P, in the color space, CS, to the color point, CPi (xi, yi). The controller is further configured to determine a shifted distance vector, D’ (x’i, y’i), from the white point, P, in the color space, CS, as a function of the light intensity level, Li, and wherein the shifted distance vector, D’ (x’i, y’i) = a-D (xi, yi), with a being a scalar factor, dependently on (as a function of) the light intensity level, Li. Hence, the shifted distance vector, D’ (x’i, y’i) may be interpreted as a shifting or scaling of the distance vector, D (xi, yi), by the scalar factor a. The controller is further configured to determine a shifted color point, CPj (x’i, y’i), in the color space, CS, as a function of the shifted distance vector, D’ (x’i, y’i). Hence, based on the shifted distance vector, D’ (x’i, y’i), which in turn is based on the light intensity level, Li, the controller is configured to determine the shifted color point, CPj (x’i, y’i), in the color space, CS. The controller is further configured to control the LEDi to emit LEDi light source light of the shifted color point, CPi (x’i, y’i). Hence, from the (initial) color point, CPi (xi, yi), in the color space, CS, of LED light emitted from the LEDi, the controller is configured to control the LEDi, via its compensation and / or correction scheme, to emit LEDi light source light of the shifted color point, CPi (x’i, y’i).

[0025] According to an embodiment of the present invention, the controller is configured to, for all LED light sources, LEDi, of the plurality of N LED light sources, wherein N> 3, select the color point, CPi (xi, yi), obtain the light intensity level, Li, determine the shifted distance vector, D’ (x’i, y’i), determine the shifted color point, CPj (x’i, y’i), and control the LEDi. The emitted LED light from any LED light source, LEDi, has a color point, CPi (xi, yi), being different from a color point, CPk (xk, yk), of the emitted LED light from another LED light source, LEDk (of the plurality of N LED light sources) and has a shifted2024PF80241

[0026] 5

[0027] color point, CPj (x’i, y’i), being different from a shifted color point, CPj (x’k, y’k), of the emitted LED light from the another LED light source, LEDk (of the plurality of N LED light sources). Hence, the controller is configured to perform the operations, steps or actions of the previous embodiment, albeit for all of N> 3 LED light sources, wherein the emitted LED light from all LED light sources have different color points, CPi (xj, yi), as well as different shifted color points, CPj (x’i, y’i). In other words, for the N> 3 LED light sources, the respective emitted LED light has a unique color point, CPi (xi, yi), and a unique shifted color point, CPj (x’i, y’i). Instead of N ≥ 3, N may also be > 5 or > 10 or > 20. According to an example, the emitted LED light from any LED light source, LEDi, has a color point, CPi (xi, yi), being different from a color point, CPk (xk, yk), of the emitted LED light from another adjacently arranged LED light source, LEDk, and has a shifted color point, CPj (x’i, y’i), being different from a shifted color point, CPj (x’k, y’k), of the emitted LED light from the another adjacently arranged LED light source, LEDk.

[0028] According to an embodiment of the present invention, the color space, CS, may be one of a Hunter Lab color space, a CIE 1931 color space, a CIE XYZ color space, a CIE 1976 UCS, and a CIELAB color space. Hence, the color space, CS, of the color point(s), CPi (xi, yi), may be a Hunter Lab color space, a CIE 1931 color space, a CIE XYZ color space, a CIE 1976 UCS or a CIELAB color space. It will be appreciated that although the color space, CS, used and / or referred to in this text is the CIE XYZ color space, CS, any other color space, CS, may be used.

[0029] According to an embodiment of the present invention, a first scalar factor, ai, associated with a first determined shifted distance vector, Di’ (x’n, y ’ii), as a function of a first light intensity level, Lii, and a second scalar factor, r / 2, associated with a second determined shifted distance vector, D2’ (x’i2, y ’12), as a function of a second light intensity level, Li2, may fulfill a > a (e.g. a > 1.2-6 / 2) if Lu < Li2 (e.g. Lu < 0.8-Li2) and a\ < az (e.g. a < 0.8-02) if Lu > Li2(e.g. Lu > 1.2-Li2). Hence, in case of a higher second light intensity level, Li2, compared to a lower first light intensity level, Lu, the second scalar factor, 02, is smaller than the first scalar factor, 01, leading to a shorter shifted distance vector, D2’ (x’i2, y’i2) = o2-D (xi2, yi2) < Di’ (x’n, y ’ii) = oy-D (xn, yn). Analogously, in case of a lower second light intensity level, Li2, compared to a higher first light intensity level, Ln, the second scalar factor, 02, is larger than the first scalar factor, 01, leading to a longer shifted distance vector, D2’ (x’i2, y’i2) = O2-D (xi2, yi2) > Di’ (x’n, y ’ii) = oy-D (xn, yn). In other words, a higher second light intensity level, Li2, compared to a lower first light intensity level, Ln, implying an intensity level increase, renders a relative decrease in the shifted distance vector, D2’ (x’i2,2024PF80241

[0030] 6

[0031] y’i2), and vice versa. The present embodiment is advantageous in that the controller corrects for the human eye color perception, wherein the color visibility of the human eye increases with increasing intensity (whereby a shorter shifted distance vector is provided by the controller), and decreases with decreasing intensity (whereby a longer shifted distance vector is provided).

[0032] According to an embodiment of the present invention, a first scalar factor, ai, associated with a first determined shifted distance vector, Di’ (x’n, y ’ii), as a function of which a first shifted color point, CPj (x’i, y’i), in the color space, CS, is determined, with a first wavelength, i, and a second scalar factor, ai, associated with a second determined shifted distance vector, Di’ (x’n, y ’ii), as a function of which a second shifted color point, CPj (x’i, y’i), in the color space, CS, is determined, with a second wavelength, Xz, fulfill at least one of (i) a < a (e.g. a < 0.8-6 / 2) if i > X nm and Xi < 2 (e.g. Xi < 0.8-Xz, Xi < 2 -20 nm and / or Xi < 2 -40 nm) and a\ > az (e.g. a\ > 1.2-02) if 2 > X nm and Xi > X2 (e.g. Xi > 1.2-Xz, Xi > 2 +20 nm and / or Xi > X2 +40 nm) and (ii) 01 < az (e.g. 01 < 0.8-6 / 2) if Xi < X nm and Xi > 2 (e.g. Xi > 1.2-X.2, Xi > X2 +20 nm and / or Xi > X2 +40 nm), and 01 > 02 (e.g. 01 > 1.2-02) if 2 < X nm and Xi < X2 (e.g. Xi < O.8A2, Xi < X2 -20 nm and / or Xi < X2 -40 nm), wherein X is in a range of 545 - 565 nm, preferably (about) 555 nm. Hence, the amplitude of the correction depends on the wavelength of the colored light, and the embodiment describes a relation between any (first) scalar factor, 01, and any (second) scalar factor, 02, and the respective wavelengths, Xi, X2, of the respectively associated shifted color points, CPj (x’i, y’i). The relation defines a minimum function at a wavelength of X nm, as (i) defines a second scalar factor, az, being larger than the first scalar factor, a, if X nm < Xi < X2, i.e. a longer shifted distance vector, D2’ (x’i2, y’i2) = r2-D (xi2, yi2) > Di’ (x’n, y ’ii) = 6 / / -D (xn, yn) for X nm < Xi (CPj (x’i, y’i)) < 2 (CPj (x’i, y’i)) for green(ish) / red(ish) color points as X is in a range of 545 - 565 nm, and the second scalar factor, az, being smaller than the first scalar factor, a, if X nm < 2 < Xi, i.e. a shorter shifted distance vector, D2’ (x’i2, y’i2) = <+?‘D (xi2, yi2) < Di’ (x’ii, y’ii) = 6 / / -D (xii, yii) for X nm < X2(CPj (x’i, y’i)) < Xi (CPj (x’i, y’i)) for green(ish) / red(ish) color points. Analogously, (ii) defines the second scalar factor, az, being larger than the first scalar factor, a, if X2 < Xi < X nm, i.e. a longer shifted distance vector, D2’ (x’i2, y’i2) = fl2-D (Xi2, yi2) > D1’ (x’n, y ’n) = 6 / y-D (xn, yn) for X2(CPj (x’i, y’i)) < Xi (CPj (x’i, y’i)) < X nm for blue(ish) / green(ish) color points as X is in the range of 545 - 565 nm, and the second scalar factor, az, being smaller than the first scalar factor, a, if Xi < X2 < X nm, i.e. a shorter shifted distance vector, D2’ (x’i2, y’i2) = r2-D (xi2, yi2) < Df (x’n, y ’n) = 6 / / -D (xii, yii) for Xi (CPj (x’i, y’i)) < 2 (CPj (x’i, y’i)) < X nm for blue(ish) / green(ish) color2024PF80241

[0033] 7

[0034] points. The present embodiment is advantageous in that the controller efficiently and accurately provides a correction for the human eye color perception as a function of color point wavelength.

[0035] According to an embodiment of the present invention, the controller may further be configured to control a light intensity, LI, of the emitted gradient device light as a function of the ambient light, AL, preferably to decrease the light intensity, LI, of the emitted gradient device light with decreasing ambient light, AL. Hence, the controller may be configured to control the light intensity, LI, of the emitted gradient device light dependently (based on) the ambient light, AL, wherein the controller preferably decreases the light intensity, LI, of the emitted gradient device light with decreasing ambient light, AL. The controller may hereby control the light intensity level, Li, as it is obtained from the ambient light, AL, and the emitted gradient device light. Consequently, the controller may conveniently control the light intensity level, Li, for a change (e.g., decrease) of the ambient light, AL.

[0036] According to an embodiment of the present invention, at least one of a minimum shifted color point Ax = |x’i-xi| > 0.05, and a minimum shifted color point Ay = |y ’i-yi| > 0.05, is fulfilled. Hence, the embodiment entails a minimum shifting in the color point for x and / or y, by the condition of Ax = |x’i-x;| > 0.05 (e.g. > 0.10) and / or Ay = |y ’ i-yi| > 0.05 (e.g. > 0.10). The present embodiment is advantageous in that the controller provides a relatively large color correction.

[0037] According to an embodiment of the present invention, a first shifted color point, CPj (x’i, y’i), in the color space, CS, dependent on a first scalar factor, ai, is determined, and a second shifted color point, CPj (x’k, y’k), in the color space, CS, dependent on a second scalar factor, a2, is determined, wherein CPj (x’i, y’i) CPj (x’k, y’k) for ai a2. Hence, the controller is configured to determine at least two different shifted color points, CPj (x’i, y’i), CPj (x’k, y’k), in the color space, CS, for respective different scalar factors, ai, a2. By “ai a2”, i.e. that the scalar factors, ai, a2, are different, it may hereby be meant that ai / a2 >1.2, or ai / a2 >1.1, or at least ai / a2 >1.05.

[0038] According to an embodiment of the present invention, the white point, P, has a correlated color temperature, CCT, in a range of 2000 - 6500 K, and preferably a distance to the black body locus, BBL, of at most 12 SDCM, such as < 10 SDCM, and more preferred < 7 SDCM.

[0039] According to an embodiment of the present invention, the shifted color point, CPj (x’i, y’i), in the color space, CS, is further determined as a function of time. Hence, the2024PF80241

[0040] 8

[0041] controller is configured to determine the shifted color point, CPj (x’i, y’i), in the color space, CS, as a function of the shifted distance vector, D’ (x’i, y’i) (which in turn is determined as a function of the light intensity level, Li) as well as being determined as a function of time. The time may, for example, be obtained by a clock module or sensor information of a sensor, e.g. a presence or distance sensor. The present embodiment is advantageous in that the controller may conveniently achieve color correction as a function of time, e.g. dependently on the time of day (morning, day, evening, night, etc.). It will be appreciated that the ambient light intensity may be dependent on the time (of day), and the controller may hereby even further improve its color correction control.

[0042] According to an embodiment of the present invention, there is provided a LED arrangement. The LED arrangement comprises a LED lighting device arranged to emit gradient device light. The LED lighting device comprises a plurality of N LED light sources, wherein each LED light source, LEDi, of the plurality of N LED light sources comprises a first LED configured to emit first LED light having a first peak emission wavelength, I, in a red wavelength range of 600 - 690 nm, preferably 610 - 660 nm, a second LED configured to emit second LED light having a second peak emission wavelength, X2, in a green wavelength range of 500 - 560 nm, preferably 510 - 540 nm, and a third LED configured to emit third LED light having a third peak emission wavelength, X3, in a blue wavelength range of 420 - 490 nm, preferably 435 - 470 nm. The LED arrangement further comprises a controller according to any one of the preceding embodiments. Hence, the controller of the LED arrangement is configured or arranged to control the one or more LEDi(s) to emit LEDi light source light of shifted color point(s), CPi (x’i, y’i), wherein each LEDi comprises, at least, a first (red) LED, a second (green) LED and a third (blue) LED. The present embodiment is advantageous in that the controller may control at least one, such as all, of the N LEDis to emit respective (RGB) LED light source light of shifted color points, CPi (x’i, y’i)- According to an example of the present invention, the LED lighting device may comprises a LED strip, a linear lighting device or a tubular lighting device. The LED lighting device may comprise one or more components configured for communication with one or more devices or units which is (are) separately arranged from the LED lighting device. For example, the LED lighting device may comprise a transmitting and / or receiving device, such as an antenna. By “LED strip”, it is here meant an elongated strip or band comprising a plurality of LEDs arranged in one or more arrays along the length of the LED strip. By “linear lighting device”, it is here meant a lighting device which has an elongated (oblong)2024PF80241

[0043] 9

[0044] form and / or comprises an elongated (oblong) housing or luminaire which comprises the components of the lighting device. By “tubular lighting device”, it is here meant a lighting device which has an elongated (oblong) tube-shaped form and / or comprises an elongated (oblong) tube-shaped housing or luminaire which comprises the components of the lighting device.

[0045] According to an embodiment of the present invention, the LED arrangement further comprises a sensor configured to determine at least one of the ambient light, AL, and the emitted gradient device light. By “sensor”, it is here meant substantially any sensor, device, unit, or the like which is configured or arranged to sense, detect, determine and / or register information and / or data, in this case light information and / or data. Hence, the (at least one) sensor of the present embodiment is configured to sense, detect, determine and / or register the ambient light, AL, and / or the emitted gradient device light. The present embodiment is advantageous in that the sensor conveniently and efficiently determines the ambient light, AL, and / or the emitted gradient device light which is (are) used by the controller of the LED arrangement to determine the light intensity level, Li. In turn, based on the light intensity level, Li, the controller is eventually configured to control the LEDi(s) of the LED arrangement to emit LED; light source light of the shifted color point(s), CPi (x’i, y’ - According to an embodiment of the present invention, the LED arrangement further comprises a user interface, UI, wherein the color points, CPi (xi, yi), are selectable by a user via the user interface, UI. By user interface, UI, it is here meant substantially any device, unit, or the like, which a user may operate for control and / or selection purposes. A user or operator may, in this embodiment, select the color point(s), CPi (xi, yi), via the UI, and the controller of the LED arrangement may accordingly use the information from the UI of the color point(s), CPi (xi, yi), in its scheme to control the LEDi(s) of the LED arrangement to emit LED; light source light of the shifted color point(s), CPi (x’i, y ’i). The present embodiment is hereby advantageous in that the UI provides a convenient color point, CPi (xi, yi), selection operation for a user / operator.

[0046] According to an embodiment of the present invention, there is provided LED luminaire. The LED luminaire comprises a LED arrangement according to any one of the preceding embodiments, and a light-transmissive envelope or cover at least partly enclosing or covering the LED arrangement.

[0047] Further objectives of, features of, and advantages with, the present invention will become apparent when studying the following detailed disclosure, the drawings and the2024PF80241

[0048] 10

[0049] appended claims. Those skilled in the art will realize that different features of the present invention can be combined to create embodiments other than those described in the following.

[0050] BRIEF DESCRIPTION OF THE DRAWINGS

[0051] This and other aspects of the present invention will now be described in more detail, with reference to the appended drawings showing embodiment(s) of the invention.

[0052] Fig. 1 schematically shows a controller for a LED lighting device according to an exemplifying embodiment of the present invention,

[0053] Fig. 2 schematically shows an operation of a controller according to an exemplifying embodiment of the present invention,

[0054] Figs. 3a and 3b schematically show color point shifting by a controller according to an exemplifying embodiment of the present invention,

[0055] Fig. 4 schematically shows a LED arrangement according to an exemplifying embodiment of the present invention,

[0056] Fig. 5 schematically shows a LED luminaire according to an exemplifying embodiment of the present invention, and

[0057] Fig. 6 schematically shows a method according to an exemplifying embodiment of the present invention.

[0058] DETAILED DESCRIPTION

[0059] Fig. 1 schematically shows a controller 100 according to an exemplifying embodiment of the present invention. The controller 100, which can have substantially any design, shape and / or configuration, and whose placement or position is substantially arbitrary, is schematically indicated in Fig. 1 as being integrated in a LED lighting device 110. The controller 100, which may constitute any unit, element, device, arrangement, or the like, is configured or arranged to control the LED lighting device 110. The LED lighting device 110 is exemplified as an elongated linear LED lighting device 110 or a tubular luminaire, but it will be appreciated that other shapes or forms of the LED lighting device 110 are feasible. The LED lighting device 110 is arranged to emit gradient device light 120. The gradient device light 120, which may comprise numerous colors, and which provides a smooth and gradual transition between colors, is exemplified as being shed onto a wall. The LED lighting device 110 comprises a plurality of LED light sources 130. The number / integer N is substantially arbitrary, but is preferably 3 or more. The controller 100 is2024PF80241

[0060] 11

[0061] configured to perform operations, actions or steps for at least one LED light source, LEDi, of the plurality of N LED light sources 130, for the control of the LED lighting device 110, as further described in Fig. 2 and the associated text.

[0062] Fig. 2 schematically shows an operation of a controller 100 according to an exemplifying embodiment of the present invention. For one or more (e.g. each) of the LED light source(s), LEDi, of the plurality of N light sources 130 (e.g. N ≥ 3) of the LED lighting device 110, the controller 100 is configured to select 140 a color point, CPi (xi, yi), in a color space, CS, of LED light emitted from the LEDi. The controller 100 is further configured to obtain 150 a light intensity level, Li, of (the) ambient (i.e. surrounding) light, AL, of the controller 100 and / or LED lighting device 110, and / or the emitted gradient device light 120 from the LED lighting device 110. The controller 100 is further configured to determine 160, for the color point, CPi (xi, yi), selected at step / operation 140, a distance vector, D (xi, yi), from a white point, P, in the color space, CS, to the color point, CPi (xi, yi). The white point, P, may be defined as a (white) point having a correlated color temperature, CCT, in a range of 1800 - 20000 K, preferably 2000 - 6500 K, and preferably a distance to the black body locus, BBL, of at most 12 SDCM, such as < 10 SDCM, and more preferred < 7 SDCM. Hence, the operations / actions 140, 150, 160 of the controller 100 describe that for the (each) color point, CPi (xi, yi), the controller 100 is configured to determine a distance vector, D (xi, yi), from a white point, P, in the color space, CS, to the color point, CPi (xi, yi). The controller 100 is further configured to determine 170 a shifted distance vector, D’ (x’i, y’i), from the white point, P, in the color space, CS, as a function of the obtained 150 light intensity level, Li. The shifted distance vector fulfills D’ (x’i, y’i) = a-D (xi, yi), with a being a scalar factor. Hence, the shifted distance vector, D’ (x’i, y’i) may be interpreted as a shifting or scaling of the distance vector, D (xi, yi), by the scalar factor a. For example, the scalar factor a may be calculated by the controller as a function of the light intensity level, or the scalar factor a may be stored in a memory (e.g. in a lookup table as a function of the light intensity level). The controller 100 is further configured to determine 180 a shifted color point, CPj (x’i, y’i), in the color space, CS, as a function of the determined 170 shifted distance vector, D’ (x’i, y’i). Hence, based on the shifted distance vector, D’ (x’i, y’i), which in turn is based on the light intensity level, Li, the controller 100 is configured to determine 180 the shifted color point, CPj (x’i, y’i), in the color space, CS. According to an example, the shifted color point, CPj (x’i, y’i), in the color space, CS, may further be determined by the controller 100 as a function of time. The controller 100 is further configured to control 190 the LEDi to emit LEDi light source light of the shifted color point, CPi (x’i, y’i). Hence, the operations / actions 140, 150,2024PF80241

[0063] 12

[0064] 160, 170, 180, 190 encompass a correction / change mechanism from the (initial) color point, CPi (xi, yi), in the color space, CS, of LED light emitted from the LEDi, whereby the controller 100 is eventually configured to control 190 the LEDi to emit LEDi light source light of the shifted color point, CPi (x’i, y’i).

[0065] It should be noted that the coordinates of the color points and distance vectors as described relate to the CIE XYZ color space. However, the x and / or y-coordinates may be translated to the other types of color space(s), CS(s), such as e.g. the Hunter Lab CS, the CIE 1931 color space, the CIELAB CS or the CIE 1976 UCS. For example, to convert from u'v' (CIE 1976 UCS) coordinates to xy chromaticity coordinates (CIE XYZ color space) in a color space, the following equations may be used: First, the value of Y (luminance) may be calculated using the equation Y = L / 100 • white_point_Y where L is the lightness value of the color, and white_point_Y is the Y value of the white point for the color space. Next, the values of X and Z using the equations u = (4 * X) / (X + 15 * Y + 3 * Z); v = (9 * Y) / (X + 15 * Y + 3 * Z); X = (9 * u * Y) / (4 * v); Z = (9 * (1 - u - v) * Y) / (4 * v); where u and v are the u'v' chromaticity coordinates of the color. Finally, the xy chromaticity coordinates may be calculated using the equation: x = X / (X + Y + Z); y = Y / (X + Y + Z), where x and y are the xy chromaticity coordinates of the color.

[0066] Figs. 3a and 3b schematically show color point shifting by a controller according to an exemplifying embodiment of the present invention. Each of Fig. 3a and 3b shows gradient device light 120 as emitted by a LED lighting device which the controller of the present invention is arranged or configured to control, in accordance with Figs. 1 and 2 and the associated texts.

[0067] Fig. 3a schematically shows three selected color points, CPi (xi, yi), namely CPi (xi, yi), CP2 (X2, y2), CP3 (X3, ys), in a color space, CS, of LED light emitted from three respective LEDs (LEDi), namely LEDi, LED2, LED3. For these three color points, CPi (xi, yi), the controller is configured to determine a (respective) distance vector, D (xi, yi), namely D (xi, yi), D (X2, y2), D (X3, ys), from a white point, P, in the color space, CS, to the respective color point, CPi (xi, yi), CP2 (X2, y2), CP3 (X3, ys). For the determination of these distance vectors, D (xi, yi), from the white point, P, in Fig. 3a, it is also referred to the operations / actions 140, 150, 160 of the controller 100 in Fig. 2.

[0068] Fig. 3b schematically shows three shifted color points, CPj (x’i, y’i), namely CPji (x’i, y’i), CPj2 (x’2, y’2), CPj3 (x’3, y’3). These (three) shifted color points, CPj (x’i, y’i), with respect to the color points, CPi (xi, yi), of Fig. 3a (and as also indicated by the circles in Fig. 3b), are determined by the controller via the respectively shifted distance vector, D’ (x’i,2024PF80241

[0069] 13

[0070] y’i), namely D’ (x’i, y’i), D’ (x’2, y’2), D’ (x’3, y’3), as a function of the obtained light intensity level, Li. For the determination of these shifted distance vectors, D’ (xi, yi) and shifted color points, CPj (x’i, y’i), it is also referred to the operation / action 170, 180 of the controller 100 in Fig. 2. The controller may, for example, be configured to achieve a minimum shifted color point Ax = |x’j-xi| > 0.05, and a minimum shifted color point Ay = |y ’j-yi| > 0.05. Furthermore, the controller is configured to control each LEDi to emit LEDi light source light of the respective shifted color point, CPi (x’i, y’i). For the control of these LEDi light source lights in Fig. 3a, it is also referred to the operation / action 190 of the controller 100 in Fig. 2.

[0071] Figs. 3a and 3b particularly exemplify cases of color point, CPi (xi, yi), correction as a function of a change of a light intensity level, Li. For example, for an increase of the light intensity level, as exemplified by the (first, relatively low) light intensity level, Lii, of Fig. 3a and (towards) the (second, relatively high) light intensity level, Li2, of Fig. 3b, the second scalar factor, 02, is smaller than the first scalar factor, ai, leading to a shorter shifted distance vector, D2’ (x’i2, y’i2) = «?’D (xi2, yi2) < Di’ (x’n, y’n) = ayD (xn, yn).

[0072] Analogously, for a decrease of the light intensity level, as exemplified by the (second, relatively high) light intensity level, Li2, of Fig. 3b and (towards) the (first, relatively low) light intensity level, Lii, of Fig. 3a, the shifted distance vector (not shown) becomes longer.

[0073] Fig. 3b further exemplifies (a) case(s) of amplitude correction depending on the wavelength of the colored light. For relatively long wavelengths, above 545 - 565 nm, such as above e.g. 555 nm, a second scalar factor, 02, is larger than a first scalar factor, ai, if 545 - 565 nm < i < 2, of the respectively associated (green(ish) / red(ish)) shifted color points, CPj (x’i, y’i), resulting in a longer shifted distance vector for a longer wavelength. Analogously, for relatively short wavelengths, below 545 - 565 nm, such as below e.g. 555 nm, a second scalar factor, 02, is larger than a first scalar factor, ai, if 2 < i < 545 - 565 nm of the respectively associated (blue(ish) / green(ish)) shifted color points, CPj (x’i, y’i), resulting in a longer shifted distance vector for a shorter wavelength.

[0074] Fig. 4 schematically shows a LED arrangement 300 according to an exemplifying embodiment of the present invention. The LED arrangement 300 comprises a controller 100 according to any previously described embodiment of the present invention, and it is hereby also referred to any one of Figs. 1, 2, 3a and / or 3b and the associated text(s) for an increased understanding of the controller 100. The LED arrangement 300 comprises a LED lighting device 110 arranged to emit gradient device light 120. The LED lighting device 110 comprises a plurality of N LED light sources 130. Each LED light source, LEDi, of the2024PF80241

[0075] 14

[0076] plurality of N LED light sources comprises three LEDs, namely a first LED 310 configured to emit first LED light having a first peak emission wavelength, λ1, in a red wavelength range of 600 - 690 nm, preferably 610 - 660 nm, a second LED 320 configured to emit second LED light having a second peak emission wavelength, λ2, in a green wavelength range of 500 - 560 nm, preferably 510 - 540 nm, and a third LED 330 configured to emit third LED light having a third peak emission wavelength, λ3, in a blue wavelength range of 420 - 490 nm, preferably 435 - 470 nm. The controller 100 may hereby perform the actions / operations according to Figs. 2, 3a and / or 3b, and the associated text(s), in order to eventually control the LEDi(s) to emit LED; light source light of the respectively shifted color points. The LED arrangement 300 may, according to an example, further comprise a sensor 350 coupled (e.g. via wire or wirelessly) to the controller 100, wherein the sensor 350 is configured to determine the ambient light, AL, and / or the emitted gradient device light. The ambient light, AL, and / or the emitted gradient device light is (are) used by the controller 100 in the action(s) / operation(s) for the determination of the shifting of the color points. The LED arrangement 300 may, according to an example, further comprise a user interface, UI 360, wherein the color points are selectable by a user 370 via the user interface, UI 360.

[0077] Fig. 5 schematically shows a LED luminaire 400 according to an exemplifying embodiment of the present invention. The LED luminaire 400 comprises a LED arrangement according to any one of preceding embodiments, and a light-transmissive envelope or cover 410 at least partly enclosing or covering the LED arrangement.

[0078] Fig. 6 schematically shows a method 500 according to an exemplifying embodiment of the present invention. The method 500 is arranged to control a LED lighting device 110 arranged to emit gradient device light, wherein the LED lighting device 110 comprises a plurality of N LED light sources 130. The method 500 comprises, for at least one LED light source, LEDi, of the plurality of N LED light sources 30 the following steps: selecting 510 a color point, CPi (xi, yi), in a color space, CS, of LED light emitted from the LEDi, obtaining 520 a light intensity level, Li, of at least one of ambient light, AL, and the emitted gradient device light, determining 530, for the color point, CPi (xi, yi), a distance vector, D (xi, yi), from a white point, P, in the color space, CS, to the color point, CPi (xi, yi), determining 540 a shifted distance vector, D’ (x’i, y’i), as a function of the light intensity level, Li, and wherein the shifted distance vector, D’ (x’i, y’i) = a-D (xi, yi), with a being a scalar factor, determining 550 a shifted color point, CPj (x’i, y’i), in the color space, CS, as a function of the shifted distance vector, D’ (x’i, y’i), and controlling 560 the LEDi to emit LEDi light source light of the shifted color point, CPi (x’i, y’i).2024PF80241

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[0080] The person skilled in the art realizes that the present invention by no means is limited to the preferred embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims. For example, one or more of the color point(s), CPi (xj, yi), distance vector(s), D (xj, yi), shifted distance vector(s), D’ (x’i, y’i), shifted color point(s), CPi (x’i, y’i), etc., may be different than those

[0081] depicted / described.

Claims

2024PF8024116CLAIMS:

1. A controller (100) for controlling a light emitting diode, LED, lighting device (110) comprising a plurality of N LED light sources (130), the plurality of N LED light sources (130) being arranged to emit gradient device light (120), and wherein the controller is configured to, for all LED light sources, LEDi, of the plurality of N LED light sources, wherein N > 3:select (140) a color point, CPi (xj, yi), in a color space, CS, of LED light to be emitted from the LEDi,obtain (150) a light intensity level, Li, of at least one ofambient light, AL, andthe emitted gradient device light,determine (160), for the color point, CPi (xi, yi), a distance vector, D (xi, yi), from a white point, P, in the color space, CS, to the color point, CPi (xi, yi),determine (170) a shifted distance vector, D’ (x’i, y’i) = a-D (xi, yi), with a being a scalar factor dependent on the light intensity level, Li,determine (180) a shifted color point, CPj (x’i, y’i), in the color space, CS, as a function of the shifted distance vector, D’ (x’i, y’i), andcontrol (190) the LEDi to emit LEDi light source light of the shifted color point, CPi (x’i, y’i),wherein the emitted LED light from any LED light source, LEDi, has a color point, CPi (xi, yi), being different from a color point, CPk (xk, yk), of the emitted LED light from another LED light source, LEDk, andhas a shifted color point, CPj (x’i, y’i), being different from a shifted color point, CPj (x’k, y’k), of the emitted LED light from the another LED light source, LEDk.

2. The controller according to claim 1, wherein the color space, CS, is one of a Hunter Lab color space,a CIE 1931 color space,a CIE XYZ color space,CIE 1976 UCS, and2024PF8024117a CIELAB color space.

3. The controller according to any one of claims 1-2, whereinfor a first obtained light intensity level, Ln, a first scalar factor, ai, associated with a first determined shifted distance vector, Df (x’n, y ’n) is determined, andfor a second obtained light intensity level, Li2, a second scalar factor, r / 2, associated with a second determined shifted distance vector, D2’ (x’i2, y’a) is determined, whereina > a if Ln < Li2, andrzi < 02 if Lii > Li2.

4. The controller according to any one of claims 1-2, whereina first scalar factor, ai, associated with a first determined shifted distance vector, Di’ (x’n, y’n), as a function of which a first shifted color point, CPj (x’i, y’i), in the color space, CS, is determined, with a first wavelength, i, anda second scalar factor, ai, associated with a second determined shifted distance vector, Di’ (x’n, y’n), as a function of which a second shifted color point, CPj (x’i, y’i), in the color space, CS, is determined, with a second wavelength, 2,fulfill at least one offli < 0 if i > X nm and Xi < X2, andfli >02 if 2 > X nm and Xi > X2,andfli < 02 if Xi < X nm and Xi > X2, andfli >02 if 2 < X nm and Xi < X2,wherein X is in a range of 545 - 565 nm.

5. The controller according to any one of claims 3-4, whereina first shifted color point, CPj (x’i, y’i), in the color space, CS, dependent on the first scalar factor, a / , is determined, anda second shifted color point, CPj (x’k, y’k), in the color space, CS, dependent on the second scalar factor, 02, is determined,wherein CPj (x’i, y’i) CPj (x’k, y’k) for ai 02.2024PF80241186. The controller according to any one of the preceding claims, further being configured to control a light intensity, LI, of the emitted gradient device light as a function of the ambient light, AL, preferably to decrease the light intensity, LI, of the emitted gradient device light with decreasing ambient light, AL.

7. The controller according to any one of the preceding claims, wherein at least one ofa minimum shifted color point Ax = |x’i-xi| > 0.05, anda minimum shifted color point Ay = |y’i-yi| > 0.05,is fulfilled.

8. The controller according to any one of the preceding claims, wherein the white point, P, has a correlated color temperature, CCT, in a range of 2000 - 6500 K, and preferably a distance to the black body locus, BBL, of at most 12 SDCM.

9. The controller according to any one of the preceding claims, wherein the shifted color point, CPj (x’i, y’i), in the color space, CS, is further determined as a function of time.

10. A light emitting diode, LED, arrangement (300), comprisinga LED lighting device (110) comprising a plurality of ALED light sources (130), the plurality of N LED light sources (130) being arranged to emit gradient device light (120), wherein each LED light source, LEDi, of the plurality of N LED light sources comprisesa first LED (310) configured to emit first LED light having a first peak emission wavelength, λ1, in a red wavelength range of 600 - 690 nm,a second LED (320) configured to emit second LED light having a second peak emission wavelength, λ2, in a green wavelength range of 500 - 560 nm, anda third LED (330) configured to emit third LED light having a third peak emission wavelength, λ3, in a blue wavelength range of 420 - 490 nm,anda controller according to any one of the preceding claims.2024PF802411911. The LED arrangement according to claim 10, further comprising asensor (350) configured to determine at least one ofthe ambient light, AL, andthe emitted gradient device light.

12. The LED arrangement according to claim 10 or 11, further comprising a user interface, UI (360), wherein the color points, CPi (xj, yi), are selectable by a user (370) via the user interface, UI.

13. A light emitting diode, LED, luminaire (400), comprisinga LED arrangement according to any one of claims 10-12, and a light-transmissive envelope or cover (410) at least partly enclosing or covering the LED arrangement.

14. The light emitting diode, LED, luminaire (400) according to claim 13, wherein the LED luminaire comprises a LED strip, a linear lighting device or a tubular lighting device.

15. A method (500) for controlling a light emitting diode, LED, lighting device (110) comprising a plurality of ALED light sources (130), the plurality of ALED light sources (130) being arranged to emit gradient device light (120), the method comprising, for all LED light sources, LEDi, of the plurality of N LED light sources, wherein A> 3:selecting (510) a color point, CPi (xi, yi), in a color space, CS, of LED light emitted from the LEDi,obtaining (520) a light intensity level, Li, of at least one ofambient light, AL, andthe emitted gradient device light,determining (530), for the color point, CPi (xi, yi), a distance vector, D (xi, yi), from a white point, P, in the color space, CS, to the color point, CPi (xi, yi),determining (540) a shifted distance vector, D’ (x’i, y’i) = a-D (xi, yi), with a being a scalar factor dependent on the light intensity level, Li,determining (550) a shifted color point, CPj (x’i, y’i), in the color space, CS, as a function of the shifted distance vector, D’ (x’i, y’i), and2024PF8024120controlling (560) the LED; to emit LED; light source light of the shifted color point, CPi (x’i, y’i),wherein the emitted LED light from any LED light source, LEDi, has a color point, CPi (xi, yi), being different from a color point, CPk (xk, yk), of the emitted LED light from another LED light source, LEDk, andhas a shifted color point, CPj (x’i, y’i), being different from a shifted color point, CPj (x’k, y’k), of the emitted LED light from the another LED light source, LEDk.

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