EP2005799B1 - Colour temperature and colour location control for a light - Google Patents

Description

The present invention relates to a method for providing control signals for a variable in their color or color temperature lamp. Moreover, the invention relates to a corresponding control device and a corresponding illumination system.

A light source generally emits light that is not monochromatic, but has a more or less broad wavelength spectrum. Therefore, in general, the color of this light can not or insufficiently described by specifying only one wavelength.

One way to at least approximately comparatively simply specify the color of the light is to specify the temperature of a black body that this black body would have to shine in a color that is equal to the color of the light source to be described, or at least that color comes as close as possible. This temperature is commonly referred to as "color temperature" or "most similar color temperature".

For the quantitative description of colors, it is customary to use certain two- or three-dimensional coordinate systems. For example, the well-known "CIE Standardfarbtafel" according to CIE 1931, DIN 5033 is used (CIE: Commission International de l'Eclairage; German: International Lighting Commission). Other examples include the so-called "CIE LAB color space" or the "CIE LCH color space". In such a coordinate system can be set with the coordinates of a "color point" that indicates a particular color.

In Fig. 2 is very schematic and simplified (notably as a black-and-white representation) the mentioned standard color chart according to CIE, 1931 is shown. In this diagram, the coordinates are usually denoted by x and y . A point (x, y) in the diagram thus indicates a color location that has a specific color features. The monochromatic colors lie along an approximately horseshoe-shaped edge region, the spectral line. In some places of this border area are in the representation of Fig. 2 the corresponding values of the associated wavelengths are entered in the unit nanometer (nm). The so-called "white point" has the coordinates x = 0.33 and y = 0.33.

It should be noted in this context that a color is a sensory impression that is subject to an individual assessment. Therefore, a certain color in the mathematical sense can not be clearly defined. However, in order to be able to describe color quantitatively, the usual systems for color description are each based on an "average color perception" of a "normal observer", which has been determined with the aid of extensive experiments (see "CIE Standard Observers" of 1931 and 1964).

From the prior art lights are known to emit light of a given color temperature. There are also known such lights with gradual adjustment for the color temperature. The Versteilstufen are chosen in these lights according to the prior art so that the differences from one level to an adjacent level each correspond to a certain difference in the color temperature.

When adjusting such a lamp over several Verstellstufen away although changes the light impression, so the (at least primary) visual impression that makes the light on an observer; however, the change is not proportional to the adjustment levels. Thus, for example, it may be the case that an operator, when moving from the first stage to the second stage, perceives a marked difference in the impression that the light imparts, but in a further adjustment to the third stage, a noticeably lesser or possibly even none at all Perceives difference in the light impression. Therefore, it is not easily possible to produce with such a lamp by appropriately adjusting a light that gives a certain desired light impression. Also, such adjustment generally takes a relatively long time.

Furthermore, lamps are known from the prior art, with which - regardless of the color temperature - light can be radiated in different colors. Usually, these lights have three different light sources, with each of which light of a particular color can be generated. The brightness of the three light sources are independently adjustable, so that it is possible to produce a corresponding mixture. In this way, light can be produced in different colors with the lamp. In general, the three colors of the three light sources in the standard color chart (cf. Fig. 2 ) are given as three color loci spanning a triangle in the underlying coordinate system. By virtue of the above-mentioned mixture of the three light sources, it is known to be possible in principle to produce a light of any color whose color locus lies within this triangle.

From the WO 2006/103600 A1 For example, a control device is known for providing control signals for a color-changeable illumination device with which pre-defined, equidistant colors can be set.

From the EP 0 574 993 A1 is a luminaire with adjustable color temperature known. For this purpose, dimming data for three differently colored light sources are stored in a storage means.

The present invention has for its object to provide a control of a lamp, and a corresponding control device and a corresponding illumination system, with or with which the setting is facilitated to a certain desired light impression.

This object is achieved with the objects of the independent claims. In the dependent claims advantageous embodiments are given.

According to a first aspect of the invention, a method is provided for providing control signals for a luminaire which can emit light of different colors. The method has the following steps a1), a2) and b): a1) input of input variables into an input unit of an inventive device A control device (see below), wherein the input quantities are two mutually different color loci, and wherein the first color locus identifies a first color and the second color locus identifies a second color that differs from the first color. a2) Depending on the first color locus and the second color locus - taking into account the following two conditions i) and ii) - a color locus to be determined which identifies a further color is determined. The first condition i) is: The color locus to be determined lies in an equidistant coordinate system representing the color loci together with the first and the second color loci at least approximately on a predefined color change curve. The second condition ii) is: The color difference between the first and the second color or an integer multiple of this color difference is at least approximately equal to the color difference between the first and the further color or between the second and the further color. Furthermore, the method comprises the following step: b) On the basis of the determined color locus, a control signal is generated, which causes the luminaire to emit light in the additional color corresponding to the determined color location.

In this case, "color difference" denotes a subjectively perceived difference between two colors, in particular between a first color of a first light and a second color of a second light. Since color perception, as mentioned, is subject to an individual assessment, it is difficult or ultimately impossible to give an "exact" objective measure of the perception of a difference between two colors. In the present context, therefore, "color difference" denotes the subjectively perceived difference between two colors, which results on the basis of a "standard color vision", as can be determined, for example, with the aid of a normal observer.

With the phrase "at least approximately equal to the color distance" is to be understood against this background that based on a "norm color vision" an inaccuracy can be set, which is a measure of a permitted deviation from the exact value. For example, a corresponding specification in a so-called "equidistant" color system is suitable for this purpose. The same applies to the formulation "at least approximately on a given color change curve.

The "color change curve" is, so to say, a path in the corresponding coordinate system, which generally does not necessarily have to represent a curve in the mathematical sense. Rather, it is a given curved or rectilinear line in the coordinate system.

According to a second aspect of the invention, a method is provided for providing control signals for a luminaire which can emit light of different colors. The method comprises the following steps a1), a2) and b): a1) input of input variables into a control unit of a device according to the invention Control device (see below), wherein the input quantities are a color locus and a color space, and wherein this color locus denotes a first color, a2) Depending on the color locus and the color space

Color difference is determined - taking into account the following two conditions i) and ii) - a color locus to be determined, which identifies a further color. The first condition i) is: The color locus to be determined lies at least approximately on a predefined color change curve in an equidistant coordinate system representing the color loci together with the predefined color locus. The second condition ii) is: The color difference between the first and the further color is at least approximately equal to the predetermined color spacing or an integral multiple thereof. The method further comprises the following step b): On the basis of the determined color locus, a control signal is generated, which causes the luminaire to emit light in the further color corresponding to the determined color locus.

With a method according to the first or second aspect of the invention, it becomes possible to produce such "lights" in a plurality of distinguishable, discrete colors with the aid of a corresponding luminaire (meaning, therefore, a first light of a first color, a second light of a second color etc.) that the differences between these colors are perceived as equidistant or at least approximately equidistant. Each step between two colors, in the sense of the color change curve of adjacent colors, corresponds to a specific color difference, which is the same in each case, and thus an equal difference between the impressions which the differently colored lights produce in a viewer.

For example, the given color change curve may be the Planckian curve. In this case, the luminaire preferably comprises three luminous means, preferably LEDs or fluorescent lamps, which can shine in different colors. The three colors can be colors whose corresponding color locations in the coordinate system span a triangle, which encloses the white point, for example, in the case of the standard color chart 1931 or a corresponding coordinate system. Furthermore, it can be provided that the color change curve runs through the white point or through a "white area";"Whitearea" is intended to denote a (small) environment around the white point, in which, again based on a standard color vision, the impression of "white" outweighs the impression of color. In this case, a color change curve can be provided which - apart from a Direction change in the "white area" - straight. In this way, the effect can be achieved that a lamp can be controlled such that it emits light in a first color, this color in uniform steps more and more white and finally in a further uniform steps in a basically any other, second Color passes over.

In a further embodiment, the given color change curve may be a straight line. In this case, the lamp advantageously has at least two lamps, preferably LEDs or fluorescent lamps, which can shine in different colors. In this case, basically (only) two bulbs are required, provided that the color change curve is chosen such that these two bulbs can shine in two colors whose corresponding color loci are on the color change curve. By correspondingly differently weighted brightness control, it is then possible to produce light in any color whose color locus lies on this color change curve.

Furthermore, in the method according to the invention, in one step, a series of at least three color loci is defined for whose three corresponding colors there is at least approximately an equal color difference between every two adjacent colors according to the color change curve.

Advantageously, in this case, a temporal control of the lamp is made such that the at least approximately equal color distances are traversed in each case in at least approximately the same time intervals. As a result, the adjustability is further facilitated.

The coordinate system chosen is a coordinate system in which a geometric distance between two color loci represents at least approximately a measure of a specific color distance, for example a so-called "equidistant" color system. For example, for this purpose, the representation of the "CIE 1976 color chart" can be selected as the coordinate system.

According to a further aspect of the invention, a control device is provided for providing control signals for a luminaire which can emit light of different colors. The control device comprises a) an input unit for input of input quantities, wherein the input quantities are either two mutually different color loci or a color locus and a color separation, and b) a calculation unit for determining a series of at least three color loci identifying three different colors, depending on the input quantities, wherein the color loci are selected so that they are at least approximately on a predetermined color change curve in a latter representing the same coordinate system, and in each case at least approximately equal color distances are present between each two adjacent colors according to the color change curve, and for determining control signals for the lamp, with the aid of which the lamp can be caused to emit light in the at least three colors (ie, is meant for the emission of a first light of the first color, a second light second color and a third light of third color, these three "lights" do not overlap in time). Furthermore, the control device c) comprises a transmission unit for transmitting the control signals to the luminaire.

In this case, the calculation unit is advantageously designed to use a method according to the invention as part of the determination of the control signals.

According to a further aspect of the invention, a lighting system is provided, which has a control device according to the invention and a light which can emit light in different colors, the control device being connected to the light.

According to a further aspect of the invention, a method is provided for providing control signals for a luminaire, with which light of different color temperature can be generated. The method has the following steps: a1) Input of input variables into one Input unit of a control device according to the invention (see below), wherein the input quantities are two mutually different color temperature values and wherein the first color temperature value corresponds to a first color and the second color temperature value corresponds to a second color different from the first color; a2) determining a color temperature setpoint corresponding to a further color as a function of the two color temperature values, wherein the color temperature setpoint is selected such that the color difference between the first and the second color or an integer multiple thereof Color distance is at least approximately equal to the color difference between the first and the other or between the second and the other color. b) Furthermore, based on the determined color temperature setpoint, a control signal is generated, which causes the lamp to emit light in the color temperature setpoint corresponding color.

In this method, therefore, a color temperature setpoint is established as a function of two different predetermined color temperature values, in short color temperatures. With the aid of this method, it is possible to set different types of light with one lamp, the types of light each differing in their color temperature, in such a way that the differences between the types of light are perceived as equidistant or at least approximately equidistant with respect to their color. Each step thus corresponds to a specific color difference, each of equal size, and thus an equal difference between the impressions which the two corresponding types of light produce in a viewer.

The invention according to this aspect uses the knowledge that a certain difference between two different color temperatures does not represent a measure of the associated difference in the light impression. A suitable measure of this is rather the so-called color difference of the light.

According to a further aspect of the invention, a method is provided for providing control signals for a luminaire, with which light of different color temperature can be generated. The method comprises the steps of: a1) inputting input quantities to an input unit of a control device according to the invention (see below), wherein the input quantities are a color temperature value and a color space and wherein the color temperature value corresponds to a first color; a2) Determining a color temperature setpoint as a function of the color temperature value and the color distance, wherein the color temperature setpoint is selected such that the color difference between the first color and the other

Color is at least approximately equal to the predetermined color difference or an integer multiple of the predetermined color distance. b) Furthermore, based on the determined color temperature setpoint, a control signal is generated, which causes the lamp to emit light in the color temperature setpoint corresponding color.

Advantageously, the lamp comprises three bulbs that can shine in different colors. In particular, the three colors can be three colors which result in white in a composition or mixture. For example, it can be red, green, and blue.

Advantageously, the three bulbs LEDs or fluorescent lamps.

Advantageously, in a further step, a series of at least three color temperature values is determined, for which three corresponding colors it is true that there is at least approximately an equal color difference between each two neighboring colors. By corresponding color is meant in this context that color in which a blackbody with the corresponding temperature lights. In this case, for example, a colorimetry can be used, which is based on a defined "standard color vision".

For a given interval of color temperature values, the respective color loci in the standard color chart can be calculated. Inserting these color locations in the x - y diagram of the standard color chart results in the so-called Planckian curve. This is in the representation of Fig. 2 schematically drawn. In some cases, the respective color temperature values are entered here. By "neighboring" colors is meant to be expressed that these colors are adjacent to the Planckian curve.

If the color temperature setpoint value is determined as a function of two predefined color temperature values T ₁ and T ₂ with T ₂ > T ₁ , then, for example, a series of three color temperature values can be defined, wherein the two predefined color temperature values represent the first two values of this series and determined color temperature setpoint TS the third value T _{3 of} the series. In this case, the color temperature setpoint TS can be determined either by choosing the color difference between TS and T ₂ equal to the color difference corresponding to the color difference between T ₁ and T ₂ or by the color difference between TS and T ₁ equal to twice the value of this color difference.

By suitable choice of the number of color temperature values, both the gradation accuracy as well as the total adjustable range can in principle be defined as precisely as desired.

Advantageously, to determine the relationship between two color temperature values and the color spacing, between the two colors corresponding to the two color temperature values, Planck's law of radiation and the normalized sensitivities of the human eye to red, green and blue light are used. Furthermore, a color coordinate system is used in which a geometric distance between two color loci represents at least approximately a measure of a specific color distance value or short color distance. For example, a color coordinate system based on a "standard color vision" can be selected for this purpose. Such a color system is referred to herein as "equidistant".

The diagram of the CIE 1976 color chart is advantageously used as the color coordinate system.

From the color temperature values of the defined row, control signals can then be formed in a known manner in a further step with which the luminaire can be controlled in such a way that it emits light of the respectively corresponding color temperature.

According to another aspect of the invention, there is provided a control apparatus for providing control signals to a luminaire capable of producing light of different color temperature, comprising: an input unit for input of input quantities wherein the input quantities are either two mutually different color temperature values or a color temperature value; a color difference value, a calculation unit for determining a series of at least three color temperature values as a function of the input variables, wherein the color temperature values are selected such that they correspond to three colors such that there is at least approximately equal color spacing between each two neighboring colors, and for determining control signals for the luminaire, with the aid of which the luminaire can be caused to emit light with the at least three color temperature values, as well as a transmission unit for transmitting mediation of the control signals to the light.

Advantageously, the calculation unit of the control device is designed to use a method according to the invention within the scope of determining the control signals.

According to a further aspect of the invention, there is provided a lighting system comprising: a control device according to the invention and a luminaire with which light of different color temperature can be generated, the control device being connected to the luminaire.

Fig. 1

eine schematische Darstellung eines erfindungsgemäßen Beleuchtungssystems,

Fig. 2

eine vereinfachte Darstellung der Normfarbtafel gemäß CIE, 1931,

Fig. 3

eine vereinfachte Darstellung der CIE-1976-Farbtafel,

Fig. 4

eine der Fig. 3 entsprechende Darstellung mit einer "Farbveränderungskurve", und

Fig. 5

eine der Fig. 3 entsprechende Darstellung mit einer weiteren "Farbveränderungskurve".

Further features, advantages and features will now be explained with reference to a detailed description of embodiments and with reference to the figures of the accompanying drawings. Show it:

Fig. 1

a schematic representation of a lighting system according to the invention,

Fig. 2

a simplified representation of the standard color chart according to CIE, 1931,

Fig. 3

a simplified representation of the CIE 1976 color chart,

Fig. 4

one of the Fig. 3 corresponding representation with a "color change curve", and

Fig. 5

one of the Fig. 3 corresponding representation with a further "color change curve".

The present invention relates in accordance with a first embodiment, the control of a lamp, with the light of different color temperature can be generated. In Fig. 1 is very schematically sketched an example of a lighting system according to the invention, which is suitable for carrying out the method according to the first embodiment.

The lighting system comprises a control unit 2 with a control device, a control line 4 and at least one lamp operating device 5 with three light sources 6, 7, 8, which form part of a luminaire 9. The bulbs 6, 7, 8 are designed to generate light in conjunction with each other with a specific color temperature. For this purpose, as the light source 6, 7, 8, for example, three light emitting diodes (LEDs) can be used, each of the LEDs can emit light of a different color, so that white light of a given color temperature is produced by suitable Zusammensatzung. For example, red, blue and green can be selected as colors for this purpose.

However, it is also possible to provide another type of lighting means 6, 7, 8, for example three fluorescent lamps with which - e.g. using color filters - light can be produced in the corresponding colors.

With the help of the control unit 2 control signals can be generated, with which the lamp 9 can be controlled such that it generates light of a specific color temperature.

The control device of the control unit 2 comprises an input unit for input of input quantities 1. The input quantities 1 may in particular be color temperature values T ₁ , T ₂ and / or a color distance value or short color difference d . Furthermore, the control device comprises a calculation unit with which a series of at least three color temperature values T ₁ , T ₂ , T ₃ can be calculated. This calculation will be discussed in more detail below. Furthermore, the calculation unit is designed to determine as output variables control signals which are suitable for driving the at least one luminaire 9 in such a way that it generates light with the at least three color temperature values T ₁ , T ₂ , T ₃ . In addition, the control device comprises a transmission unit for transmitting the control signals to the luminaire 9.

For example, two or more such lights 9 may be provided for the lighting system.

The control signals are used in a conventional manner to control the at least one lamp 9. The control line 4 can be part of a bus system, for example, the DALI technology can be used (DALI: Digital Addressable Lighting Interface). In the lamp operating device 5, the corresponding setting value for the luminaire 9 or the three luminous means 6, 7, 8 is generated from the digital signal, which represents a specific color temperature value.

• Gemäß einem ersten Ausführungsbeispiel ist vorgesehen, dass als Eingabegrößen 1 zwei unterschiedliche Farbtemperaturwerte T₁ und T₂ gewählt werden. Aus T₁ und T₂ werden dann zunächst unter Zuhilfenahme des Plank'schen Strahlungsgesetzes die zwei Intensitätsverteilungen I₁ (λ) und I₂ (λ) in Abhängigkeit der Wellenlänge λ ermittelt, die den jeweils entsprechenden Schwarzkörperstrahlungen entsprechen. I₁ (λ) bezeichnet also die Intensitätsverteilung der Strahlung, die ein schwarzer Körper mit der Temperatur T₁ aussendet und I₂ (λ) diejenige eines schwarzen Körpers mit der Temperatur T₂ . Die Intensitätsverteilung I(λ) der Strahlung eines schwarzen Körpers kann dabei allgemein formuliert bekanntermaßen durch das Planck'sche Strahlungsgesetz in Abhängigkeit von der Temperatur T wie folgt angegeben werden: $$\mathit{I}\left(\mathit{\lambda }\right)0=\frac{2\hslash c^2}{{\mathrm{<figure-callout\; id="5"\; label="\lambda "\; filenames="imgf0001.png,imgf0005.png"\; state="\{\{state\}\}">\lambda </figure-callout>}}^5}\frac{1}{e^{\frac{\mathrm{\hslash c}}{\mathit{\lambda kT}}}-1}\mathrm{.}$$
  

In the following, the central element of the invention, which can be seen in the area of the calculation of the at least three color temperature values T ₁ , T ₂ , T ₃ , will be discussed in greater detail. For this purpose, two embodiments are given below:

• According to a first exemplary embodiment, it is provided that two different color temperature values T ₁ and T _{2 are} selected as input variables 1. From T ₁ and T ₂ , the two intensity distributions I ₁ (λ) and I ₂ (λ) are then determined as a function of the wavelength λ, which correspond to the respectively corresponding black body radiation, with the aid of Plank's law of radiation. I ₁ (λ) thus denotes the intensity distribution of the radiation which a black body with the temperature T ₁ emits and I ₂ (λ) that of a black body with the temperature T ₂ . The intensity distribution I (λ) of the radiation of a black body can be stated in general formulated as known by Planck's law of radiation as a function of the temperature T as follows: $$\mathit{I}\left(\mathit{\lambda }\right)0=\frac{2\hslash c^2}{{\mathrm{<figure-callout\; id="5"\; label="\lambda "\; filenames="imgf0001.png,imgf0005.png"\; state="\{\{state\}\}">\lambda </figure-callout>}}^5}\frac{1}{e^{\frac{\mathrm{\hslash c}}{\mathit{\lambda kT}}}-1}\mathrm{,}$$
  

Where ℏ is Planck's constant, c is the speed of light, and k is Boltzmann's constant.

$$Y=\int I\left(\lambda \right)\cdot \bar{y}\left(\lambda \right)\mathit{d\lambda }$$

$$Z=\int I\left(\lambda \right)\cdot \bar{z}\left(\lambda \right)\mathit{d\lambda }$$

In a next step, the color impression is determined, which is caused in the case of a person of normal color vision when viewing the visible portion of the radiation with the intensity distribution I ₁ (λ). The same procedure is followed for I ₂ (λ). For this purpose, the intensity distribution I (λ) is generally formulated first. as follows with the sensitivities of the human eye for red, green and blue light x . y . z weighted: $$X=\int I\left(\lambda \right)\cdot \tilde{x}\left(\lambda \right)\mathit{d\lambda }$$

$$Y=\int I\left(\lambda \right)\cdot \tilde{y}\left(\lambda \right)\mathit{d\lambda }$$

$$Z=\int I\left(\lambda \right)\cdot \tilde{z}\left(\lambda \right)\mathit{d\lambda }$$

$$\mathit{vʹ}=\frac{6X}{X+15Y+3Z}$$

mit den Koordinaten u' und v'der "CIE-1976-Farbtafel" in Beziehung. Bei dieser Farbtafel handelt es sich um eine Farbtafel, bei der Farbabstände zumindest näherungsweise den geometrischen Abständen zwischen den entsprechenden Farborten in der Farbtafel entsprechen. Bei der CIE-1976-Farbtafel handelt es sich allgemeiner formuliert um eine "gleichabständige" Farbart-Tafel, auch als CIE-UCS-Farbtafel bezeichnet (UCS: Uniform-Chromaticity-Scale Diagram; CIE 1976).Here, X , Y , and Z denote the known standard color values according to CIE. These are about the equations $$\mathit{u\; \text{'}}=\frac{4X}{X+15Y+3Z}$$

$$\mathit{v\; \text{'}}=\frac{6X}{X+15Y+3Z}$$

with the coordinates u 'and v ' of the "CIE 1976 color chart" in relation. This color chart is a color chart in which color distances correspond at least approximately to the geometric distances between the corresponding color locations in the color chart. More generally, the CIE 1976 color chart is an "equidistant" chromaticity chart, also called the CIE UCS color chart (UCS: Uniform Chromaticity-Scale Diagram, CIE 1976).

It should be noted at this point that the CIE 1976 color chart is not the only possible equidistant color chart or colorimetric. In principle, any other equidistant color representation can be used analogously in the context of the invention. In the exemplary embodiment given here, therefore, the CIE 1976 color chart is selected purely by way of example for this purpose.

Thus, using the above equations, a first color locus (u ' ₁ , v' ₁ ) of the CIE 1976 color chart is calculated, which describes the color of the black body radiation at the temperature T ₁ and, analogously, a second color locus (u ' ₂ , v' ₂ ) for the temperature T ₂ .

In a further step, the color difference d between the first and the second color location is then calculated. Since this color distance d is at least approximately proportional to the geometric distance between these two color loci in the representation of the CIE 1976 color chart, it can be calculated as follows from u ' _1,2 and v' _1,2 : $$d=\sqrt{{\left({\mathit{u\; \text{'}}}_1-{\mathit{u\; \text{'}}}_2\right)}^2+{\left({\mathit{v\; \text{'}}}_1-{\mathit{v\; \text{'}}}_2\right)}^2}$$

The coordinates u ' and v' can be expressed as functions of the temperature T ; also the function v ' ( u' ) can be formed, which results if one specifies a set of color temperature values for T. In this way you get the Plank curve, here for the CIE 1976 color chart. For

Color temperatures T in the range between 1500 K and 10000 K are obtained in this way for v ' ( u' ): $$\mathit{v\; \text{'}}=500{\mathit{u\; \text{'}}}^5-875{\mathit{u\; \text{'}}}^4+610{\mathit{u\; \text{'}}}^3-212.5{\mathit{u\; \text{'}}}^2+37.2\mathit{u\; \text{'}}-2.27$$

In addition, one of the two color loci, ie, for example, the second color locus ( u ' ₂ , v' ₂ ) is assumed and a third color locus (u ' ₃ , v' ₃ ) is calculated, for which it is valid from the second color locus (u ' ₂ , v' ₂ ) has the color difference d and likewise lies on the Planckian curve, but differs in the corresponding color temperature value T ₃ from the color temperature value T ₁ corresponding to the first color location (u ' ₁ , v' ₁ ) corresponds. Due to the quadratic relationship, such a color locus is generally found on the Plank curve. Thus, in the u ' - v' diagram of the CIE 1976 color plate around the second color locus ( u ' ₂ , v' ₂ ), which is located on the Plank curve, a circle with the Color difference d beaten. This circle intersects the Planckian curve generally once to the right and once to the left of the center, ie the color locus (u ' ₂ , v' ₂ ), where an intersection point is given by the first color locus (u ' ₁ , v'1 ) and the second intersection represents the new, sought-after color location (u ' ₃ , v' ₃ ).

In addition, the associated color temperature, which is referred to below as T ₃ , can then be inferred from the third color locus ( u ' ₃ , v' ₃ ), again using the above-mentioned relationships.

The color temperature value T ₃ can thus be referred to as the "color temperature setpoint" TS to be determined.

In this way, therefore, a series of three color temperature values T ₁ , T ₂ , T _{3 has been} formed, for which they correspond to three colors such that between every two on the Planckian curve in the u ' - v' diagram adjacent colors each have an equal Parbabstand d exists.

From these three color temperature values T ₁ , T ₂ , T ₃ , control signals are then formed in a manner known per se which can serve to activate the luminaire 9 in such a way that it produces light with the color temperature values mentioned.

In an analogous manner, a series of four or even more color temperature values can also be calculated, so that in general any desired range or interval of color temperatures and an arbitrarily accurate graduation can be achieved. An example of such a series of seven temperatures T ₁ , T ₂ , T ₃ ... T ₇ is the color temperature series: 2500 K, 2700 K, 3000 K, 3400 K, 4000 K, 4900 K, 6500 K.

In this way it is thus possible to provide a step-like adjustability for a corresponding luminaire, in which the impression of the light in each case changes at least approximately uniformly when adjusting between the individual steps. Overall, therefore, compared to the prior art, the adjustability can be significantly facilitated and accelerated.

It should be noted at this point that the above relationships can of course be shortened in practice. In particular, therefore, a direct relationship between the color temperature T on the one hand and the coordinates u ' and v' on the other hand can be specified. The above selected representation was chosen only to make the connections particularly clear.

In the following, the case is given as a variant in which only one color temperature value T ₁ and one color difference value d are selected as input quantities 1.

The temperature value T ₁ corresponds, according to the relationships described above, to a specific first color location ( u ' ₁ , v' ₁ ). For example, for T ₁ = 2000 K the color locus with the coordinates u ' ₁ = 0.3050 and v' ₁ = 0.3591 results. Using the fixed color distance d and with the aid of equations (7) and (8), it is now possible to calculate a second color location ( u ' ₂ , v' ₂ ) which determines the color distance d from the first color location ( u ' ₁ , v ' ₁ ). For this second color location ( u ' ₂ , v' ₂ ), the associated color temperature T ₂ can then be calculated, again in accordance with the relationships described above.

Analogously, a further color temperature value T ₃ can now be determined whose distance from T ₂ in turn corresponds to the color distance d , etc. By repeated application of these calculation steps, a sequence of n color locations (u ' ₁ , v'1) , (u' ₂ , v ' ₂ ), ... (u' _n , v ' _n ) are determined, for which applies that the perceived color difference, ie the color difference d between two successive or adjacent color locations is the same size, namely the Value d corresponds.

Since the coordinates u ' and v' are functions of the color temperature T as described, this sequence can be assigned a series of color temperature values T ₁ , T ₂ , ... T _n , for which therefore their corresponding colors each have an equal size Have color difference d

With the invention according to the above-described first embodiment is made possible for a luminaire, with which light of different color temperatures can be generated to provide a step-like adjustability, in such a way that with an adjustment between the individual stages of the impression that the light Observer conveys, each at least approximately uniform, ie proportional to the levels changed. Overall, therefore, compared to the prior art, the adjustability significantly easier and faster, so be made more comfortable.

The second embodiment of the present invention relates to the driving of a lamp 9, which can emit light in different colors. In the following, only the differences with respect to the first exemplary embodiment presented above will be discussed. The illumination system with which a method according to the second embodiment can be carried out, corresponds - unless otherwise stated below - the in Fig. 1 system shown, wherein the three bulbs 6, 7, 8 can generate light in three different colors. As already stated at the outset, light with a color can be generated in this case with the light 9, which is marked or represented within a triangle by a color locus in a corresponding coordinate system, in particular color diagram, whereby the triangle is spanned by those three color loci that correspond to the colors of the three light sources 6, 7, 8. With the help of the control unit 2 so control signals can be generated with which the lamp 9 can be controlled such that it generates light of a particular color, which can be characterized by a specific color location in a color chart.

Furthermore, in contrast to the first exemplary embodiment, the input variables 1 can now be, in particular, color loci F ₁ , F ₂ and / or a color difference d . The control device comprises a calculation unit with which a series of at least three color locations F ₁ , F ₂ , F ₃ can be calculated. Furthermore, the calculation unit is designed to determine as output variables control signals which are suitable for controlling at least one luminaire 9 such that it generates light in three different colors that correspond to the three different color loci F ₁ , F ₂ , F ₃ .

Starting point for this second embodiment is a basically freely selectable color change curve K1 between two color loci F _A and F _E. This is in Fig. 4 schematically drawn in, as well as in Fig. 3 , a simplified illustration of the CIE 1976 color chart is sketched. The two color loci F _A and F _E are located within a color triangle D , which has three color loci as corner points, which correspond to the three colors of the three luminous means 6, 7, 8. It should be noted that in the presentation of the Fig. 4 these three vertices are merely sketched in principle and do not necessarily correspond to color locations, for whose corresponding colors in each case a corresponding lighting means actually exists.

The color change curve K1 is selected as a straight line according to this embodiment. Therefore, depending on the location of the color loci F _A and F _E, the color change curve K1 can be specified in each case either as v 'as a function of u' and / or as u ' as a function of v ' in the mathematical sense. The corresponding mathematical function then allows a clear description of all color locations that lie on K1 .

It will now be chosen as a starting point two color locations F ₁ and F ₂ on the color change curve K1 , the two (sensory) different

Mark colors. For example, in this case F _A or F _{E can be selected} as F _I. Taking into account the following two conditions, a - generally formulated "further" color location F _x - is determined here as the "third" color location F ₃ . The first condition is that the third color locus F ₃ lies on the color change curve K1 . The second condition is that the color difference d between F ₁ and F _{2 is} equal to the color difference between F ₂ and F ₃ . In this way, therefore, a series of three color loci is determined, for which three corresponding colors, that between each two adjacent according to the color change curve K1 colors at least approximately equal in color distance d is present.

Purely by way of example is in Fig. 4 drawn a case in which five color locations F ₁ to F _{5 is formed} , each with the same color spacing d as a series of color locations. Generally mathematically formulated, a series (F;) of i color locations with i ∈ N can be formed.

Analogously to the second variant mentioned in the first exemplary embodiment, this series of color loci can again be determined on the basis of (only) a predefined color locus (for example F ₁ ) and a predetermined color spacing d .

The color change curve can basically take any shape. In particular, it is therefore also possible to choose a line which has at least one curved or "bent" one. Section has. For the calculation, it holds true that in this case as well, depending on the location of the color loci F _A and F _E, the color change curve is given sufficient accuracy in the mathematical sense by a function v '(u') or u '(v') , or, if necessary, can be described by a function composed in sections of the last two functions.

According to another example, the color change curve comprises two respective rectilinear portions which enclose a non-zero angle and which are connected to each other at one end. The connection point lies in the white point or in the "white area" (as defined above). The respective other end points of the two sections, that is to say using the above terminology the end points F _A and F _E , lie at two color locations, each one identify specific color. Thus, it is possible to control a corresponding lamp such that - starting from light of a certain color, the color is changed in uniform steps so far that a "white" light is produced and subsequently this white light in turn evenly spaced in light of a second Color is changed.

According to a third embodiment, it is provided that a straight line is again selected as the color change curve, but that connects two color locations whose corresponding colors can be formed by light in each case of a luminous means. In the presentation of the Fig. 5 these two color loci are labeled FL ₁ and FL ₂ , and the corresponding color change curve is K2 . Furthermore, the calculation method corresponds again to the last-mentioned embodiment. It should be noted that in this case a luminaire 9 can be provided which has only two illuminants which can illuminate in colors corresponding to the color loci FL ₁ and FL ₂ . In the mentioned example of the color change curve K2 , the first illuminant may, for example, be an LED which emits light of wavelength 480 nm, and the second illuminant may be an LED which emits light of wavelength 600 nm.

For all of the embodiments given above, a preferred option with regard to the timing of the luminaire 9 is that the color loci F ₁ , F ₂ , F ₃ ... of the series < F _i > are traversed in at least approximately equal time intervals. This makes it possible to generate or pass through the corresponding light row with only one operating movement for operating the control unit. In this case, it is unnecessary to initiate each individual color step individually. This makes the control even more comfortable. It is also advantageous in this case when the control unit is designed such that also the time interval between the individual color levels can be specified.

With the invention it is possible to provide a step-like adjustability for a luminaire with which light of different colors or color temperatures can be generated, such that when an adjustment is made between the individual steps, the impression which the light conveys to an observer, respectively at least approximately uniform, that is proportional to the levels changed. Overall, therefore, compared to the prior art, the adjustability significantly easier and faster, so be made more comfortable.

Claims (21)

1. A control device to provide control signals for a luminaire (9) which can radiate light in different colours,
   comprising:

   a) an input unit for the input of input quantities (1),
   wherein the input quantities (1) are either two colour locations (F₁, F₂ ) which differ from each other or one colour location (F₁ ) and one colour distance (d),

   b) a computation unit

   - for determining a series of at least three colour locations (F₁, F₂, F₃ ), which identify three different colours, depending on the input quantities (1), the colour locations (F₁, F₂, F₃ ) being chosen so that in an equidistant co-ordinate system which represents the latter they lie at least approximately on a specified colour change curve (K1, K2), and that between any two colours which are adjacent according to the colour change curve (K1, K2), at least approximately equally great colour distances (d) are present, and

   - for determining, for the luminaire (9), control signals using which the luminaire (9) can be caused to radiate light in the at least three colours, and also

   c) a transmission unit (4, 5) for transmitting the control signals to the luminaire (9).
2. A lighting system, having

   - a control device according to claim 1, and

   - a luminaire (9) which can radiate light in different colours,
   wherein the control device is connected to the luminaire (9).
3. A method of providing control signals for a luminaire (9) which can radiate light in different colours,
   having the following steps:

   a1) input of input quantities (1) into an input unit of a control device according to claim 1, wherein the input quantities (1) are two colour locations (F₁ , F₂ ) which differ from each other, and wherein the first colour location (F₁ ) identifies a first colour, and the second colour location (F₂ ) identifies a second colour which differs from the first colour,

   a2) depending on the first colour location (F₁ ) and the second colour location (F₂ ) - subject to the two conditions i) and ii) below - a colour location (F_X ) which is to be determined and identifies a further colour is determined:

   i) the colour location (F_X ) to be determined, in an equidistant co-ordinate system which represents the colour locations (F₁ , F₂, F_X ), together with the first and the second colour location (F₁, F₂ ), lies at least approximately on a specified colour change curve (K1), and

   ii) the colour distance (d) between the first and the second colour, or an integer multiple of this colour distance (d), at least approximately equals the colour distance between the first and the further colour or between the second and the further colour, and

   b) on the basis of the determined colour location (F_X ), a control signal which causes the luminaire (9) to radiate light in the further colour corresponding to the determined colour location (F_X ) is generated.
4. A method of providing control signals for a luminaire (9) which can radiate light in different colours,
   having the following steps:

   a1) input of input quantities (1) into an input unit of a control device according to claim 1, wherein the input quantities (1) are one colour location (F₁ ) and one colour distance (d), and wherein this colour location (F₁ ) identifies a first colour,

   a2) depending on the colour location (F₁ ) and the colour distance (d) - subject to the two conditions i) and ii) below - a colour location (F_X ) which is to be determined and identifies a further colour is determined:

   i) the colour location (F_X ) to be determined, in an equidistant co-ordinate system which represents the colour locations (F₁, F_X ), together with the specified colour location (F₁ ), lies at least approximately on a specified colour change curve (K1), and

   ii) the colour distance between the first and the further colour at least approximately equals the specified colour distance (d) or an integer multiple of it, and

   b) on the basis of the determined colour location (F_X ), a control signal which causes the luminaire (9) to radiate light in the further colour corresponding to the determined colour location (F_X ) is generated.
5. A method according to claim 3 or 4,
   wherein the specified colour change curve is the Planckian locus.
6. A method according to one of claims 3 to 5,
   wherein the luminaire (9) comprises three lighting means (6, 7, 8), preferably LEDs or fluorescent lamps, which can emit light of different colours.
7. A method according to claim 3 or 4,
   wherein the specified colour change curve (K2) is a straight line.
8. A method according to claim 7,
   wherein the luminaire (9) comprises at least two lighting means, preferably LEDs or fluorescent lamps, which can emit light of different colours.
9. A method according to one of claims 3 to 8,
   wherein in a step, a series of at least three colour locations (F₁, F₂, F₃ ) is defined in such a way that, for their three corresponding colours, between any two colours which are adjacent according to the colour change curve, at least approximately an equally great colour distance (d) is present.
10. A method according to claim 9,
    wherein the luminaire (9) is controlled temporally so that the at least approximately equally great colour distances (d) are passed through at substantially equal time intervals.
11. A method according to one of claims 3 to 10, wherein, as the co-ordinate system, a co-ordinate system is chosen in which a geometrical distance between two colour locations at least approximately represents a measure of a certain colour distance (d).
12. A method according to one of claims 3 to 11,
    wherein the representation of the CIE 1976 colour table is chosen as the co-ordinate system.
13. A control device to provide control signals for a luminaire (9) with which light of different colour temperature can be generated,
    comprising:

    a) an input unit for the input of input quantities (1),
    wherein the input quantities (1) are either two colour temperature values (T₁, T₂ ) which differ from each other or one colour temperature value (T₁ ) and one colour distance value (d),

    b) a computation unit
    for determining a series of at least three colour temperature values (T₁, T₂, T₃ ), depending on the input quantities (1), the colour temperature values (T₁, T₂, T₃ ) being chosen so that they correspond to three colours in such a way that between any two adjacent colours, at least approximately equally great colour distances (d) are present, and for determining, for the luminaire (9), control signals using which the luminaire (9) can be caused to radiate light with the at least three colour temperature values, and

    c) a transmission unit (4, 5) for transmitting the control signals to the luminaire (9).
14. A lighting system, having

    - a control device according to claim 13, and

    - a luminaire (9) with which light of different colour temperature can be generated,
    wherein the control device is connected to the luminaire (9).
15. A method of providing control signals for a luminaire (9) with which light of different colour temperature can be generated,
    having the following steps:

    a1) input of input quantities (1) into an input unit of a control device according to claim 13, wherein the input quantities (1) are two colour temperature values (T₁, T₂ ) which differ from each other, and wherein the first colour temperature value (T₁ ) corresponds to a first colour, and the second colour temperature value (T₂ ) corresponds to a second colour which differs from the first colour, and

    a2) determination of a colour temperature setpoint value (TS) which corresponds to a further colour, depending on the two colour temperature values (T₁, T₂ ), wherein the colour temperature setpoint value (TS) is chosen so that the colour distance (d) between the first and the second colour, or an integer multiple of this colour distance (d) at least approximately equals the colour distance between the first and the further or between the second and the further colour, and

    b) on the basis of the determined colour temperature setpoint value (TS) a control signal which causes the luminaire (9) to radiate light in the further colour corresponding to the determined colour temperature setpoint value (TS) is generated.
16. A method of providing control signals for a luminaire (9) with which light of different colour temperature can be generated,
    having the following steps:

    a1) input of input quantities (1) into an input unit of a control device according to claim 13, wherein the input quantities (1) are one colour temperature value (T₁ ) and one colour distance (d), and wherein the colour temperature value (T₁ ) corresponds to a first colour, and

    a2) determination of a colour temperature setpoint value (TS) which corresponds to a further colour,
    depending on the colour temperature value (T₁ ) and the colour distance (d), wherein the colour temperature setpoint value (TS) is chosen so that the colour distance (d) between the first colour and the further colour at least approximately equals the specified colour distance (d) or an integer multiple of the specified colour distance (d), and

    b) on the basis of the determined colour temperature setpoint value (TS) a control signal which causes the luminaire (9) to radiate light in the further colour corresponding to the determined colour temperature setpoint value (TS) is generated.
17. A method according to claim 15 or 16,
    wherein the luminaire comprises three lighting means (6, 7, 8), which can emit light of different colours.
18. A method according to claim 17,
    wherein the three lighting means (6, 7, 8) are LEDs or fluorescent lamps.
19. A method according to one of claims 15 to 18, wherein, in a further step, a series of at least three colour temperature values (T₁, T₂, T₃ ) is defined in such a way that, for their three corresponding colours, between any two adjacent colours at least approximately an equally great colour distance (d) is present.
20. A method according to one of claims 15 to 19,
    wherein to determine the relationship between two colour temperature values (T₁, T₂ ) and the colour distance (d) between the two colours corresponding to the two colour temperature values (T₁, T₂ ), with the aid of Planck's radiation law and the sensitivities of the human eye to red, green and blue light ( x , y , z ), a co-ordinate system in which a geometrical distance between two colour locations at least approximately represents a measure of a certain colour distance (d) is used.
21. A method according to claim 20,
    wherein the representation of the CIE 1976 colour table is chosen as the co-ordinate system.

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