EP3032918A1 - Method for operating an assembly for emitting light with adjustable intensity and/or colour location - Google Patents

Abstract

The invention relates to a method for operating an arrangement (2) which is arranged to emit light adjustable in its brightness and / or color locus and which has at least two electrically controllable LED light sources (4, 5, 6) which are in a dominant wavelength of the light generated by them, the light emitted by the device (2) being produced by additive mixing of the light produced by the individual LED light sources (4, 5, 6), the LED light sources (4, 5, 6) are individually supplied with direct current in such a way that a predetermined dominant wavelength of the light emitted by the arrangement (2) is constant irrespective of the respective brightness of this light and / or that a predetermined brightness of the light emitted by the arrangement (2) regardless of the respective predetermined dominant wavelength of this light is constant.

Description

The invention relates to a method for operating a set up for emitting in its brightness and / or its color adjustable light arrangement, which has at least two electrically controllable LED light sources, which differ from each other in a dominant wavelength of the light generated by them, wherein the light emitted from the array is produced by additive mixing of the light generated by each of the LED light sources.

Furthermore, the invention relates to a system for generating light which is adjustable in its brightness and / or color locus, comprising at least one arrangement for emitting light adjustable in its brightness and at least one electronic control unit arranged to drive the arrangement, the arrangement being at least two electrical having controllable LED light sources, which differ from one another in a dominant wavelength of the light they generate, wherein the LED light sources are controllably designed and arranged relative to one another such that the light emitted by the arrangement by additive mixing of the light emitted by the individual LED Light sources generated each light is generated.

A dominant wavelength is one way of describing a polychromatic light mixture by a monochromatic light that produces a similar color perception as the polychromatic light mixture. In the 1931 CIE standard color chart known to those skilled in the art, a line connecting the white point contained in the CIE standard color chart and a point for the color of a polychromatic light mixture generated by a light source may be extrapolated such that the line is the edge of the CIE Standard color chart cuts in two intersections. The point of intersection which is closer to the point for the color of the polychromatic light mixture represents the dominant wavelength of the color of this light mixture as the wavelength of a monochromatic light or a specific pure spectral color. The dominant wavelength is dependent on the entire course of the optical spectrum, which has the light to be characterized with regard to the color locus. Often, a spectrum is also characterized by characteristic Parameters, such as the peak wavelength and the half-width, described. However, the color locus is uniquely determined by these parameters only if further information about the spectrum is known, such as symmetry properties. If an LED has, for example, a Gaussian shape, the spectrum and thus the dominant wavelength are uniquely determined by specifying the peak wavelength and the half-width. However, this does not apply to any other, in particular asymmetrical spectra. For this reason, in the present specification, the color locus is described by the dominant wavelength and not by other spectral parameters.

Arrangements for emitting brightness adjustable light having at least two LED light sources are known. Such arrangements are usually supplied with a pulsed electrical current for controlling the brightness of the light emitted by them, the pulse width of which is modulated according to the desired brightness. It is thus continuously switched back and forth between a current zero and a constant current, the resulting average current strength determines the optical radiometric radiation power and the photometric radiation power and thus the brightness of each emitted by the assemblies light. This pulsed driving of respective devices causes the light emitted by the devices to be pulsed.

It should be noted at this point that the term adjustable can include both a control in the strict sense, ie with a closed feedback loop, and a control in the strict sense, ie without a closed feedback loop. It is both a regulation of the brightness or the color location and a controller possible.

It is known that the dominant wavelength or color locus in the CIE standard color chart of a light generated by an LED light source strongly depends on the current magnitude of the current supplied to the LED light source. Not only can the peak wavelength change, but also the shape and / or width of the spectrum. In the above-described pulsed driving of an arrangement, the current of the current supplying the LED light sources is constant during one pulse width, whereby the light generated by the LED light sources of the device or the light emitted from the device substantially during one pulse width has a constant dominant wavelength or a constant color location. A slight change in the dominant wavelength or the color locus of the light is effected in the above-described control of an arrangement, however, that at a lower average current intensity of the power supply to the LED light sources of the arrangement, ie with a reduction of the pulse width against a pulse pause electrical power dissipation is lower. This is in the operation of an arrangement with a lower heating of the arrangement or the LED light sources of the arrangement and thus with an influence on the spectral behavior of the LED light sources, in particular with a shift of the dominant wavelength and optionally with a change in the shape of a LED light source generated light spectrum, accompanied. It is known to correct this temperature effect by means of a corresponding characteristic curve or a corresponding characteristic field, which or which is used for setting the LED light source or LED light sources with pulsed current.

A disadvantage of the conventional arrangements is that the pulsed light emitted by these arrangements is unsuitable if it leads to undesirable effects when used. This is the case, in particular, when using such illumination for film recordings, since in this case the frequency of the pulsed light can lead to beats at the refresh rate. This effect could be achieved by synchronizing the pulse rate of light emitted by the array with the frame rate, i. H. the refresh rate at which the images of a movie recording are generated, are eliminated. However, this would lead to an undesirably high technical complexity. In addition, due to different pulse widths of the different LED light sources in digital image processing, disturbing false-color image segments or black stripes in the image reproduction may occur. In addition, pulsating light with frequencies <1 kHz in the case of long-term exposure is perceived as disturbing and in terms of well-being by the human eye as a concern.

The object of the invention is to enable emitting in its brightness and / or its color adjustable light with an arrangement of the type mentioned, in which the above-mentioned disadvantages do not occur.

This object is achieved by a method having the features according to claim 1 and system having the features according to claim 10. Advantageous embodiments are given in the subclaims and the description which, taken alone or in different combination with one another, can represent an aspect of the invention.

The method of the type mentioned is characterized according to claim 1, characterized in that the LED light sources are individually supplied with direct current such that a predetermined dominant wavelength of the light emitted by the arrangement is independent of the respective brightness of this light is constant and / or that the LED light sources are individually supplied with direct current such that a predetermined brightness of the light emitted from the array is constant regardless of the respective dominant wavelength of this light. The predetermined dominant wavelength can be fixed or adjustable.

According to the invention, the LED light sources of the arrangement are supplied with a direct current, that is to say with an unpulsed current, so that the light emitted by the arrangement is not pulsed, as is conventional, but continuous. This avoids the disadvantages described above with respect to the prior art. A control or regulation of the brightness and / or the color location of the light emitted by the arrangement is effected by a control or regulation of the current intensity of the individual LED light sources individually supplying direct current.

According to the invention, the LED light sources are supplied with direct current in such a way that a predetermined dominant wavelength of the light emitted by the arrangement is constant, irrespective of the respective brightness of this light or, in the entire range in which the brightness of the light, ie the photometric radiation power (ie the luminous flux measured in lumens), can only be adjusted by a predetermined maximum amount. This means that the set dominant wavelength or the color locus of the light emitted by the arrangement is always the same regardless of the respectively set brightness. This can be achieved by the individual supply of the individual LED light sources of the arrangement with direct current.

Additionally or alternatively, the LED light sources are individually supplied with direct current in such a way that a predetermined brightness of the light emitted by the arrangement is constant irrespective of the respective dominant wavelength of this light or, in the entire range in which the brightness of the light, ie the photometric Radiation power (ie measured in lumens luminous flux), can be adjusted only by a predetermined maximum amount varies. This means that the adjusted brightness of the light emitted by the arrangement is always the same regardless of the respective, in particular variable, dominant wavelength of this light. This can be achieved by the individual supply of the individual LED light sources of the arrangement with direct current.

An arrangement operated according to the method of the invention may also have three or more LED light sources. Also, a plurality of LED light sources, in particular connected in series with one another, may be present of each type of LED light source. The arrangement can be set up to emit colored, white and / or variable light in its color location.

The LED light sources of the arrangement can be supplied by means of a driver circuit with a DC current whose current is adjustable via the driver circuit, but is kept constant after the respective setting to a desired value.

According to an advantageous embodiment, at least one LED light source is supplied with direct current taking into account a predetermined dependence of the dominant wavelength of the light generated by this LED light source of a current strength of this DC light source supplying this LED light source. For this purpose, a characteristic curve can be used which reproduces the dependence of the dominant wavelength of the light generated by the LED light source on the current intensity of the direct current supplying this LED light source. Such a characteristic may additionally include a predetermined dependence of the dominant wavelength of the light generated by the LED light source on a temperature of this LED light source and / or on a temperature of the arrangement. Also, two or more or all of the LED light sources may be each taking into account a predetermined dependence of the dominant wavelength of the light generated by the respective LED light source on the current intensity of the direct current supplying the respective LED light source be supplied with direct current. The predetermined dependence may include coordinates of the CIE standard color chart with respect to the dominant wavelength and the color location of the light generated by the respective LED light source.

From the individual characteristics or characteristic curves for all individual LED light sources, the individual drive currents for the individual LED light sources, which ensure that the color location of the light emitted by the entire arrangement (within predetermined limits) is constant, can be determined in a variety of ways , For example, a multi-dimensional dependence of the brightness-defining luminous flux of the light generated by the entire arrangement on the associated individual drive currents for the individual LED light sources can be set up. Then, with a manipulated variable (for example, the resistance value of a potentiometer or a digital value of a control signal), a value set for the luminous flux can be preset. From the known dependency, the individual drive current for the individual LED light sources can then be determined immediately and selected or set accordingly. The multidimensional dependence can also include and take into account the temperature dependence of the dominant wavelengths of the individual LED light sources. The aging or degradation of the LED light sources can also be taken into account.

The brightness control may also be effected so that an LED light source, which may be referred to as a guide LED light source, is supplied with a freely selectable current. Since the dependence of the dominant wavelength of this guide LED light source is known, all other LED light sources can be driven, taking into account their dependencies of the respective dominant wavelength of the respective DC supply current with a DC current selected such that the predetermined dominant wavelength of the entire assembly emitted light remains constant or fluctuates only within a tolerated value range. So here is not the luminous flux of the light generated by the entire arrangement can be predetermined, but the current strength of the drive current for the guide LED light source. Of course, this also depends on the luminous flux of the light generated by the guide LED light source, but usually not linearly over the entire desired adjustment range for the luminous flux of the guide LED light source. As a guide LED light source you will be that LED light source which provides the largest contribution to the luminous flux of the light generated by the entire array.

According to a further advantageous embodiment, a temperature of at least one LED light source is detected, wherein this LED light source is supplied with direct current taking into account a predetermined dependence of the dominant wavelength of the light generated by this LED light source of the temperature of this LED light source. For this purpose, a characteristic curve can be used which reproduces the dependence of the dominant wavelength of the light generated by the LED light source on the temperature of the respective LED light source. Such a characteristic can be used during operation of the arrangement to compensate for a temperature-dependent change in the dominant wavelength of the light generated by the LED light source or cancel by a corresponding control or regulation of the power supply of the LED light source. Here one will often use a regulation in the strict sense to compensate for temperature fluctuations continuously (i.e., continuously or at certain time intervals, which may be so short that one can speak of a quasi-continuous control). It is also possible to supply two or more, in particular all, LED light sources in each case taking into account a predetermined dependence of the dominant wavelength of the light generated by the respective LED light source on the temperature of the respective LED light source. The temperature of an LED light source can be detected by means of a temperature sensor. The predetermined dependence may include coordinates of the DIE standard color chart with respect to the dominant wavelength and the color location of the light generated by the respective LED light source.

A further advantageous embodiment provides that at least one LED light source is supplied with direct current, taking into account a predetermined dependence of the dominant wavelength of the light emitted by the arrangement on a current strength of the DC power supplying the arrangement as a whole. For this purpose, a characteristic curve can be used which reproduces the dependence of the dominant wavelength of the light generated by the LED light source on the current intensity of the direct current supplying the arrangement as a whole. Such a characteristic curve may additionally have a predetermined dependence of the dominant wavelength of the light generated by the LED light source on a temperature of this LED light source and / or from a temperature of the assembly. Two or more, in particular all, LED light sources can each be supplied with direct current taking into account a predetermined dependence of the dominant wavelength of the light generated by the respective LED light source on the current intensity of the DC power supplying the arrangement as a whole. The predetermined dependence may include coordinates of the CIE standard color chart with respect to the dominant wavelength and the color location of the light generated by the respective LED light source.

It is furthermore considered advantageous if at least one LED light source is supplied with direct current taking into account a predetermined dependence of the dominant wavelength of the light emitted by the arrangement on a temperature of the arrangement. For this purpose, a characteristic curve can be used which reproduces the dependence of the dominant wavelength of the light generated by the LED light source on the temperature of the arrangement. Such a characteristic can be used during operation of the arrangement to compensate for a temperature-dependent change in the dominant wavelength of the light generated by the LED light source or cancel by a corresponding control or regulation of the power supply of the LED light source. It is also possible to supply two or more, in particular all, LED light sources each with consideration of a predetermined dependence of the dominant wavelength of the light generated by the respective LED light source on the temperature of the arrangement with direct current. The predetermined dependence may include coordinates of the CIE standard color chart with respect to the dominant wavelength and the color location of the light generated by the respective LED light source.

According to a further advantageous embodiment, at least one LED light source is supplied with direct current, taking into account the current intensity of a DC current supplying at least one further LED light source. It is also possible to supply two or more LED light sources with direct current, taking into account the current intensity of a direct current supplying at least one further LED light source. For this purpose, a characteristic curve or a characteristic field can be used which, for given dominant wavelengths or color locations of the light emitted by the arrangement, the dependence of the current intensity of the current supplying the at least one LED light source on the current strength of at least one further LED light source supplying DC power. As a result, in the case of a change in the current intensity of the current supplying the at least one further LED light source, the intensity of the current supplying the at least one LED light source can be adjusted in order to keep the dominant wavelength or color locus of the light emitted by the arrangement constant. The tracking can be continuous or discrete at intervals of about 10 ms to about 100 ms. In sufficiently close to each other arranged characteristics or characteristic curves, which differ only by small differences in the current strength of the at least one further LED light source supplying DC, the respective next characteristic curve or the respective next characteristic field for determining the current strength of the at least a LED light source supplying DC power can be selected. Instead, it is also possible to carry out a linear interpolation between values from two adjacent characteristic curves or characteristic fields or a non-linear interpolation from values for more than two adjacent characteristic curves or characteristic fields. Such a characteristic curve or such a characteristic field may additionally contain a predetermined dependence of the dominant wavelength of the light generated by the LED light source on a temperature of this LED light source and / or on a temperature of the arrangement.

According to a further advantageous embodiment, the LED light sources are supplied with direct current in such a way that the color locus of the light emitted by the arrangement lies in at least one predetermined partial region of a color temperature range from 1500 K to 10000 K on or in the vicinity of the Planckian curve. The size of the partial region is preferably at least 1000 K, preferably at least 2000 K or particularly preferably at least 3000 K. The partial region preferably extends from 3500 K to 4500 K, preferably from 3500 K to 5500 K or particularly preferably from 2700 K to 6500 K. The Planckian curve is included in the 1941 CIE standard color chart, which is known to those skilled in the art. The course of Planck's curve is defined by the colors of the radiation of a blackbody at different temperatures.

Advantageously, the LED light sources are supplied with direct current such that the color locus of the light emitted in each case by the arrangement within a MacAdam ellipse associated with a reference hue lying on the Planckian curve the preferred value is 10, 6, 4, 3 or less. These values are a measure of the size of the MacAdam ellipse. The mathematical context for the MacAdam ellipse is 12.5 * X ² + 17.5 * X * Y + 33.25 * Y ² + 6.25 - 12.5 * X - 27.5 * Y = 0 and X + Y + Z = 1, where X, Y and Z represent the tristimulus values. The color locus may thus be within a MacAdam ellipse of 10, 6, 4, 3, or smaller on or near the Planckian curve. This high accuracy with respect to the desired optimum location of the color locus of the light emitted in each case with the arrangement makes it possible to keep the color locations of the light emitted by the arrangement as close as possible or on the Planckian curve.

The system of the type mentioned is characterized according to claim 9, characterized in that the electronic control unit for implementing the method according to one of the aforementioned embodiments or any combination thereof is set up. With this system, the advantages and embodiments mentioned above with respect to the method are connected accordingly. The electronic control unit may comprise at least one microprocessor. The achievable with the electronic control unit control or regulation of the arrangement can optimally adapt the arrangement to the respective application. In particular, the LED light sources can be controlled by means of the electronic control unit with respect to the electrical power respectively the emitted optical radiometric power or the emitted photometric power respectively absorbed by them so that the desired color location results.

The electronic control unit may comprise a driver circuit, which drives the LED light sources each with a predetermined electrical power to produce light with an overall spectrum having the desired color temperature and the desired color location, in particular on or in the vicinity of the Planckian curve, having. For this purpose, each individual LED light source can be connected to an associated output of the driver circuit. But it can also be provided per light source, an output of the driver circuit, wherein the individual LED light sources can be connected in series and / or connected in parallel with the output of the driver circuit.

According to an advantageous embodiment, the LED light sources comprise the arrangement at least one LED light source configured to generate blue light, in particular having a dominant wavelength between 380 nm and 480 nm, which has at least one light emitting diode, at least one LED light source configured to produce conversion light having a color lying in a conversion range, the at least one light-emitting diode configured to produce blue light and at least one conversion unit configured for photoluminescence, and / or at least one for generating red, in particular with a dominant wavelength between 600 nm and 640 nm, or green light, in particular with a dominant wavelength between 500 nm and 560 nm configured LED light source, which has at least one light emitting diode.

Depending on the intended use, the arrangement can also have two or more, for example, in series, LED light sources of each type of LED light source. Within the scope of the invention, the arrangement can also have two or more blue light-emitting diodes, conversion light sources and / or red light sources as well as different combinations of these components in order to be able to optimally adapt the arrangement to different applications, in particular with regard to the intensity of the light which can be emitted by it. The LED light sources can be controlled by the electronic control unit with respect to the respectively recorded electrical power or emitted optical radiometric power or emitted photometric power so that a desired color location, in particular on or in the vicinity of the Planckian curve results , By this controllability of the arrangement or its components, for example, a very accurate simulation of real daylight in a room, such as an office room done by the course of the color temperature of the daylight (yellowish morning and evening and bluish noon) is simulated. However, the arrangement may also be driven to produce white light with a constant color temperature.

The LED light source configured to generate conversion light may comprise one, two or more light emitting diodes configured to produce blue light, the light of which is emitted in part by the device and used in part to excite the conversion device configured for photoluminescence. The dominant wavelength of the blue light generated by a light emitting diode of the LED light source configured to generate conversion light may be smaller than the dominant wavelength of the conversion light generated by the blue light excited by the conversion unit by photoluminescence.

The LED light source configured to generate red light may also comprise at least one conversion unit and at least one light emitting diode, wherein the light emitting diode is to be arranged to the conversion unit such that at least a part of the light generated by the light emitting diode impinges on the conversion unit. After that, instead of a red light-emitting red light-emitting diode, a light-emitting diode, in particular a blue light, and a suitable conversion unit are thus used to form the LED light source configured to generate red light. Alternatively, a red LED configured to generate red light may be used to form the LED light source configured to generate red light.

According to a further advantageous embodiment, the system has at least one temperature sensor with which the temperature of at least one LED light source, in particular directly or indirectly detectable. With the temperature sensor and the temperature of two or more, in particular all, LED light sources or the entire arrangement can be detected. The temperature sensor is wireless or cabled connected to the electronic control unit. Alternatively, the temperature of at least one LED light source may also be determined indirectly from the light generated by the LED light source, for example from the peak wavelength or half width of the generated spectrum. Further, the temperature of at least one LED light source may be determined from electrical properties such as voltage drop or capacitance.

According to a further embodiment of the system according to the invention, information is stored in at least one nonvolatile electronic memory which serves to determine the current strengths of the individual supply currents for at least one of the at least two of the LED light sources.

• eine Abhängigkeit der dominanten Wellenlänge des von wenigstens einer LED-Lichtquelle erzeugten Lichts von einer Stromstärke eines diese LED-Lichtquelle versorgenden Gleichstroms oder eine andere, diese Abhängigkeit beinhaltende Information und/oder,
• eine Abhängigkeit der dominanten Wellenlänge des von der Anordnung emittierten Lichts von einer Stromstärke eines die Anordnung versorgenden Gleichstroms oder eine andere, diese Abhängigkeit beinhaltende Information, und/oder
• eine Abhängigkeit einer Stromstärke eines wenigstens eine LED-Lichtquelle versorgenden Gleichstroms von der Stromstärke eines wenigstens eine weitere LED-Lichtquelle versorgenden Gleichstroms oder eine andere, diese Abhängigkeit beinhaltende Information.

It is furthermore considered advantageous if the system has at least one non-volatile electronic memory in which at least one is stored

• a dependence of the dominant wavelength of the light generated by at least one LED light source of a current strength of this LED light source supplying Direct current or another information containing this dependence and / or
• a dependence of the dominant wavelength of the light emitted by the device on a current strength of a DC power supplying the device, or another, this dependency containing information, and / or
• a dependency of a current intensity of a DC current supplying at least one LED light source on the current strength of a direct current supplying at least one further LED light source or another information containing this dependence.

With this embodiment, the above-mentioned with reference to the method Vorbeile and embodiments are connected accordingly.

• eine Abhängigkeit der dominanten Wellenlänge des von wenigstens einer LED-Lichtquelle erzeugten Lichts von der Temperatur, insbesondere von der Temperatur einer Sperrschicht dieser LED-Lichtquelle oder eine andere, diese Abhängigkeit beinhaltende Information, und/oder
• eine Abhängigkeit der dominanten Wellenlänge des von der Anordnung emittierten Lichts von einer Temperatur der Anordnung oder eine andere, diese Abhängigkeit beinhaltende Information.

It is also proposed that is stored in the nonvolatile electronic memory

• a dependence of the dominant wavelength of the light generated by at least one LED light source on the temperature, in particular the temperature of a barrier layer of this LED light source or another, this dependency containing information, and / or
• a dependence of the dominant wavelength of the light emitted by the device on a temperature of the device or another, this dependency containing information.

This dependency or dependencies can be taken into account via separate characteristic curves for controlling or regulating the power supply of the LED light source. Alternatively, the dependency or the dependencies can be contained in a characteristic which reproduces at least one of the dependencies of the advantageous embodiment mentioned immediately above.

Fig. 1:

eine schematische Darstellung eines Ausführungsbeispiels für ein erfindungsgemäßes System;

Fig. 2:

ein Diagramm, das die CIE-Normfarbtafel und Farborte von LED-Lichtquellen eines Ausführungsbeispiels für ein erfindungsgemäßes System enthält;

Fig. 3:

einen Ausschnitt des in Figur 2 gezeigten Diagramms, der die Abhängigkeit eines Farbortes des von einer LED-Lichtquelle erzeugten Lichts von der Stromstärke des diese LED-Lichtquelle versorgenden Gleichstroms zeigt;

Fig. 4:

einen weiteren Ausschnitt des in Figur 2 gezeigten Diagramms, der die Abhängigkeit eines weiteren Farbortes des von einer weiteren LED-Lichtquelle erzeugten Lichts von der Stromstärke des diese LED-Lichtquelle versorgenden Gleichstroms zeigt;

Fig. 5:

ein Diagramm, das die CIE-Normfarbtafel und Farborte von LED-Lichtquellen eines Ausführungsbeispiels für ein erfindungsgemäßes System bei verschiedenen Temperaturen der LED-Lichtquellen enthält;

Fig. 6:

einen Ausschnitt des in Figur 5 gezeigten Diagramms, der die Abhängigkeit eines Farbortes des von einer LED-Lichtquelle erzeugten Lichts von der Temperatur dieser LED-Lichtquelle zeigt;

Fig. 7:

einen weiteren Ausschnitt des in Figur 5 gezeigten Diagramms, der die Abhängigkeit eines weiteren Farbortes des von einer weiteren LED-Lichtquelle erzeugten Lichts von der Temperatur dieser LED-Lichtquelle zeigt.

In the following, the invention will be explained by way of example with reference to the attached figures with reference to preferred exemplary embodiments, wherein the features illustrated below may represent an aspect of the invention both individually and in different combinations with one another.
Show it

Fig. 1:

a schematic representation of an embodiment of a system according to the invention;

Fig. 2:

a diagram containing the CIE standard color chart and color loci of LED light sources of an embodiment of a system according to the invention;

3:

a section of the in FIG. 2 a graph showing the dependence of a color locus of the light generated by an LED light source on the current intensity of the direct current supplying this LED light source;

4:

another section of the in FIG. 2 2, which shows the dependence of a further color location of the light generated by a further LED light source on the current intensity of the direct current supplying this LED light source;

Fig. 5:

a diagram containing the CIE standard color chart and color loci of LED light sources of an embodiment of a system according to the invention at different temperatures of the LED light sources;

Fig. 6:

a section of the in FIG. 5 a diagram showing the dependence of a color location of the light generated by an LED light source on the temperature of this LED light source;

Fig. 7:

another section of the in FIG. 5 shown diagram showing the dependence of another color location of the light generated by another LED light source of the temperature of this LED light source.

FIG. 1 shows a schematic representation of an embodiment of an inventive system 1 for generating in its brightness and / or its color adjustable light. The system 1 comprises an arrangement 2 for emitting light which can be adjusted in its brightness and an electronic control unit 3 set up for activating the arrangement 2.

The arrangement 2 comprises three electrically controllable LED light sources 4, 5 and 6, which are in the dominant wavelength of each light generated by them differ, wherein the LED light sources 4, 5 and 6 are so controllably formed and arranged to each other that the light emitted from the array 2 light is produced by additive mixing of each of the individual LED light sources 4, 5 and 6 generated light.

The LED light sources 4, 5 and 6 of the arrangement 2 comprise an LED light source 4 configured to generate blue light, which has at least one light-emitting diode (not shown), an LED light source 5 configured to produce conversion light with a color lying in a conversion range comprising at least one unillustrated LED configured to generate blue light and at least one conversion unit not shown for photoluminescence, and an LED light source 6 configured to generate red light having at least one light emitting diode (not shown).

The system 1 further comprises one or more temperature sensors 7, with which the temperature of the individual LED light sources 4, 5 and 6 or the arrangement 2 can be detected and outputs the temperature signals to the electronic control unit 3. If a plurality of temperature sensors 7 are provided, then in each case a temperature sensor 7 can be assigned to a specific LED light source 4, 5 or 6 or to a light-emitting diode of the relevant light source 4, 5 or 6. It is of course also possible to assign one of a plurality of temperature sensors 7 to a plurality of selected LED light sources 4, 5 and 6, respectively. The one or more temperature sensors 7 may be formed in any manner, both as independent components and as at least partially integrated with other components trained sensors. Thus, for example, the forward voltage or the specific emission behavior of the LED light sources 4, 5 and 6 or one or more of the relevant light-emitting diodes can be used to determine the temperature.

• eine Abhängigkeit der dominanten Wellenlänge des von wenigstens einer LED-Lichtquelle 4, 5 oder 6 erzeugten Lichts von einer Stromstärke eines diese LED-Lichtquelle 4, 5 bzw. 6 versorgenden Gleichstroms,
• eine Abhängigkeit der dominanten Wellenlänge des von der Anordnung 2 emittierten Lichts von einer Stromstärke eines die Anordnung 2 insgesamt versorgenden Gleichstroms, und/oder
• eine Abhängigkeit einer Stromstärke eines wenigstens eine LED-Lichtquelle 4, 5 oder 6 versorgenden Gleichstroms von der Stromstärke eines wenigstens eine weitere LED-Lichtquelle 4, 5 oder 6 versorgenden Gleichstroms.

Der nichtflüchtige elektronische Speicher 8 kann als EPROM oder EEPROM ausgebildet sein und ist kommunikationstechnisch mit der elektronischen Steuereinheit 3 verbunden.The system 1 further comprises a nonvolatile electronic memory 8, in which at least is stored

• a dependence of the dominant wavelength of the light generated by at least one LED light source 4, 5 or 6 from a current intensity of a DC current supplying this LED light source 4, 5 or 6,
• a dependence of the dominant wavelength of the light emitted by the arrangement 2 on a current intensity of the arrangement 2 as a whole supplying direct current, and / or
• a dependence of a current intensity of at least one LED light source 4, 5 or 6 supplying direct current from the current of at least one further LED light source 4, 5 or 6 supplying direct current.

The non-volatile electronic memory 8 may be formed as EPROM or EEPROM and is communicatively connected to the electronic control unit 3.

In addition, in the non-volatile electronic memory, a dependence of the dominant wavelength of the light generated by at least one LED light source 4, 5 or 6 on the temperature of this LED light source 4, 5 or 6 and / or a dependence of the dominant wavelength of the Arrangement 2 emitted light can be stored by a temperature of the arrangement 2.

The electronic control unit 3 is set up to supply the LED light sources 4, 5 and 6 individually with direct current such that a dominant wavelength of the light emitted by the arrangement 2 is constant, regardless of the respective brightness of this light. For this purpose, the arrangement 2, in particular their interconnects, so connected to the control unit 3 and the control unit 3 is formed so that each of the LED light sources 4, 5 and 6 is controlled with such electrical power or is driven, that the respective LED Light source 4, 5 or 6 emits such a spectrum that the additive mixed total spectrum represents light with the desired properties.

The electronic control unit 3 can also be set up to supply the LED light sources 4, 5 and 6 individually with direct current in such a way that a brightness of the light emitted by the arrangement 2 is constant irrespective of the variable, dominant wavelength of this light.

For this purpose, the control unit 3, an electronic controller 9 and three communication technology associated with the electronic control driver circuits 10, 11 and 12, wherein in each case a driver output to one of the LED light sources 4, 5 or 6 is connected. The driver circuits 10, 11 and 12 are controlled so that the LED light sources 4, 5 and 6 are operated individually with a predetermined constant direct current, so that the spectra generated by the LED light sources 4, 5 and 6 have the desired properties, in particular the radiometric or photometric power set by the brightness adjustment according to the invention. The electronic controller 9 may include at least one microcontroller.

The electronic control unit 9 is communicatively connected to an input interface 18, via which the default values for a desired color location or for a dominant wavelength of the light emitted by the arrangement 2 and / or a desired brightness of the light emitted by the arrangement 2 can be generated, which are wireless or wired to the electronic control can be transmitted. The input interface 18 may comprise, for example, a potentiometer, a wirelessly coupled mobile unit, for example a mobile radio terminal, in particular a smartphone, or the like. When using a potentiometer for setting the desired color locus or the brightness of the light emitted by the arrangement 2, the input interface 18 can additionally comprise a unit for generating digital values corresponding to the default values, which can be processed by the electronic controller 9 or by its microcontroller , If a smartphone is used, which generates digital values corresponding to the default values and can transmit them directly to the electronic controller 9 or its microcontroller, a receiving unit for the electronic controller 9 can be present in order to be able to receive the digital values generated by the smartphone.

FIG. 2 shows a diagram containing the designated by the reference numeral 13 CIE standard color chart 1931. Further, in the diagram, a color locus 14 of the light generated by an LED light source 4 configured to generate blue light, a color locus 15 of the light generated by a red LED light source 6, and a color locus 16 of one for generating conversion light having a color lying in a conversion range, LED light source 5 generated light, wherein the color locus 16 is in a green-yellow color range. Furthermore, in the diagram, the Planckian curve 17 is located. The color locations 14, 15 and 16 are connected to form a triangle by lines, with the triangle all with a corresponding arrangement 2 possible adjustable color locations of the emitted light from the arrangement 2 are defined.

FIG. 3 shows a section of the in FIG. 2 in the region of the color locus 14, which shows the dependence of the color locus 14 of the light generated by the created for generating blue light LED light source 4 of the current intensity of this LED light source 4 supplying direct current. A color locus 14 is plotted for each set current intensity, the color locus 14 having the largest y value being assigned a current value of 1 mA and the color locus 14 having the smallest y value being assigned a current value of 200 mA. The color loci 14 were each determined shortly after the power was turned on by the LED light source 4 to eliminate temperature effects in the operation of the LED light source 4 with DC.

FIG. 4 shows a section of the in FIG. 2 in the area of the color locus 15, which shows the dependence of the color locus 15 of the light generated by the created for generating red LED light source 6 of the current intensity of this LED light source 6 supplying direct current. A color location 15 is plotted for each set current intensity, the color location 15 having the largest y value having a current intensity of 1 mA and the color location 15 having the smallest y value being assigned a current value of 40 mA. The color loci 15 were each determined shortly after the power was turned on by the LED light source 6 to eliminate temperature effects in the operation of the LED light source 6 with DC.

FIG. 5 FIG. 12 is a diagram showing the CIE standard color chart 13 and color loci 14, 15 and 16 of LED light sources 4, 5 and 6 of an embodiment of a system 1 according to the invention at different temperatures of the LED light sources 4, 5 and 6 in a range of approximately From -40 ° C to about 120 ° C. This is more accurate FIGS. 6 and 7 refer to.

FIG. 6 shows a section of the in FIG. 5 in the area of the color locus 14, which shows the dependence of the color locus 14 of the light generated by the created for generating blue light LED light source 4 of the temperature of this LED light source 4. It is a color location for different temperatures 14, wherein the color locus 14 with the largest y-value of the temperature 120 ° C and the color locus 14 with the smallest y-value of the temperature -40 ° C is assigned. In the FIG. 6 The measured values shown were recorded with current pulses with a duration of 500 ns and a repetition rate of 500 μs in order to be able to rule out any influence of the heating of the blocking layer of the LED light source 4.

FIG. 7 shows another section of the in FIG. 5 in the vicinity of the color locus 15, which shows the dependence of the color locus 15 of the light generated by the LED light source 6 on the temperature of this LED light source 6. In each case one color locus 15 is drawn for different temperatures, wherein the color locus 15 with the largest y value of the temperature -40 ° C. and the color locus 15 with the smallest y value of the temperature 120 ° C. are assigned. In the FIG. 7 The measured values shown were recorded with current pulses having a duration of 500 ns and a repetition rate of 500 μs in order to be able to rule out any possible influence of the heating of the blocking layer of the LED light source 6.

The in the FIGS. 2 to 7 shown dependencies of the LED light sources 4, 5 and 6 or of the LED light sources 4, 5 and 6 respectively generated light from the temperature of the LED light sources 4, 5 and 6 and the current intensity of each of the LED light sources 4, 5 and 6 supplying direct current is taken into account via corresponding dependencies containing characteristic curves or fields in the individual supply of the LED light sources 4, 5 and 6 with direct current in order to adjust the brightness of a light emitted by a corresponding arrangement 2 light, without the color location of this additively mixed light to change.

In the following, an exemplary embodiment of the method according to the invention is described in which a regulation of the supply of n LED light sources 1 to n with the individual direct currents I ₁ to I _n takes place in a special manner. One or more characteristics or characteristic diagrams are necessary for this regulation, in which the dependence of the color locus or the dominant wavelength λ _d of the light emitted by the arrangement 2 on the individual direct currents I ₁ to I _n through the individual LED light sources 1 to n is taken into account, without the influence of the respective temperature of the individual LED light sources 1 to n, which, as described, is determined by the DC currents I ₁ to I _n by the LED light sources 1 to n only briefly turns on and while capturing the dominant wavelength. The dependence the color location of the light emitted by the arrangement 2 light from the individual DC currents I ₁ to I _n through the individual LED light sources 1 to n is deliberately switched off in the conventional pulse width-modulated control of LED light sources. On the other hand, the at least one characteristic curve or the at least one characteristic diagram takes into account the additional dependence of the color location of the light emitted by the arrangement 2 on the temperatures T of the individual LED light sources 1 to n or the temperatures of the barrier layers of the individual LED light sources 1 to n.

It is thus possible to use a characteristic map in which, within value ranges for the individual quantities, all possible n-tuples for the quantities I ₁ to I _n , λ _d , Q (brightness of the light emitted by the arrangement 2), T are included. For the brightness Q, theoretically, the luminous flux PHI measured in lumens can also be used. However, in practice, one tends to tend to use a normalized brightness, for example between zero (or a lower limit, eg 10% of the maximum achievable brightness) and 100% of the maximum achievable brightness (this can also be dependent on the color locus). In the map only the currents I ₁ to I _{n are} true independent parameters (within given ranges of values). The parameters λ _d and Q depend on the independent parameters I ₁ to I _n and result from the independent parameters. Also, the parameter T is not completely independent of the independent parameters I ₁ to I _n . The independent parameters I ₁ to I _n influence the junction temperature of the respective LED light source 1 to n. However, the respective junction temperature additionally depends on the respective ambient temperature and the respective heat transfer resistance, which is decisive for the release of heat from the respective barrier layer to the environment is.

In a first step, starting values for currents I0 ₁ to I0n can be determined as a function of predefined values for the color locus or λ _d and the desired brightness Q (eg 80% of the maximum brightness). These starting values can be taken, for example, for a normal temperature T from the large map. Instead, a separate characteristic field can be used for this, which links the values for I0 ₁ to I0 _n , λ _d and Q for a specific temperature T (eg room temperature).

In a second step, the temperature influence can then be taken into account, where-bei a temperature sensor 7 supplies a temperature value which already deviates initially from an initial temperature. From the map, or a separate map, then new values for the DC currents I ₁ to I _{n can be taken} for the new temperature value and the LED light sources 1 to n are controlled accordingly.

The second step can also be divided into two sub-steps, wherein in a first sub-step only the temperature influence on the direct currents I ₁ to I _{n is} corrected in order to maintain λ _d . A characteristic map used for this purpose can only take into account the temperature dependence, without taking into account the influence of the changed direct currents I ₁ to I _n on the color locus of the light emitted by the arrangement 2. Such a characteristic diagram can suffice for controlling / regulating pulsed controlled LED light sources 1 to n, since there is no dependence of the color locus of the light emitted by the arrangement 2 on the direct currents I ₁ to I _n of temperature effects. In a second sub-step, the modified DC currents I ₁ to I _n can then be corrected by means of a further characteristic map in which the dependence of the color locus of the light emitted by the device 2 on the DC currents I ₁ to I _n is determined Color location of the emitted light from the arrangement 2 is achieved or maintained. The modified direct currents I ₁ to I _n will then again have an influence on the temperature T, etc. In the manner described, a desired state of equilibrium can be achieved starting from three such iterative steps. Alternatively, the regulation can also be carried out (quasi) continuously.

LIST OF REFERENCE NUMBERS

1

system

2

arrangement

3

control unit

4

LED light source

5

LED light source

6

LED light source

7

temperature sensor

8th

non-volatile electronic memory

9

electronic control

10

driver circuit

11

driver circuit

12

driver circuit

13

CIE color chart

14

color location

15

color location

16

color location

17

Planck's curve

18

Input interface

Claims (14)

A method of operating an arrangement (2) arranged to emit light adjustable in its brightness and / or chromaticity, comprising at least two electrically controllable LED light sources (4, 5, 6), each at a dominant wavelength light generated by the arrangement (2) emitted by additive mixing of each of the individual LED light sources (4, 5, 6) generated light,
characterized,
that the LED light sources (4, 5, 6) are so individually supplied with direct current, that a predefined dominant wavelength of the assembly (2) emitted light is independent of the respective brightness of this light constant, and / or
in that the LED light sources (4, 5, 6) are individually supplied with direct current in such a way that a predetermined brightness of the light emitted by the arrangement (2) is constant irrespective of the respective dominant wavelength of this light. A method according to claim 1, characterized in that at least one LED light source (4, 5, 6) taking into account a predetermined dependence of the dominant wavelength of the light source of this LED (4, 5, 6) generated by a current strength of this LED Light source (4, 5, 6) supplying DC power is supplied. A method according to claim 1 or 2, characterized in that a temperature of at least one LED light source (4, 5, 6) is detected, said LED light source (4, 5, 6) taking into account a predetermined dependence of the dominant wavelength of supplied by this LED light source (4, 5, 6) is supplied with direct current from the temperature of this LED light source (4, 5, 6). Method according to one of claims 1 to 3, characterized in that at least one LED light source (4, 5, 6) taking into account a predetermined dependence of the dominant wavelength of the light emitted by the arrangement (2) of a current strength of the arrangement (2 ) is supplied with DC current supplying total DC power. Method according to one of claims 1 to 4, characterized in that at least one LED light source (4, 5, 6) taking into account a predetermined dependence of the dominant wavelength of the light emitted by the arrangement (2) of a temperature of the arrangement (2) is supplied with direct current. Method according to one of Claims 1 to 5, characterized in that at least one LED light source (4, 5, 6) is supplied with direct current taking into account the current intensity of a direct current supplying at least one further LED light source (4, 5, 6). Method according to one of Claims 1 to 6, characterized in that the LED light sources (4, 5, 6) are supplied with direct current such that the color locus of the light respectively emitted by the arrangement (2) is in at least one predetermined subarea of a color temperature range from 1500 K to 10000 K on or near the Planckian curve (17). Method according to one of Claims 1 to 7, characterized in that the LED light sources (4, 5, 6) are supplied with direct current in such a way that the color locus of the light respectively emitted by the arrangement (2) is located within a zone on the Planck '. lying on the curve (17) associated with MacAdam ellipse with the preferred value 10, 6, 4, 3 or smaller. System (1) for generating light adjustable in its brightness and / or color locus, comprising at least one arrangement (2) for emitting light adjustable in its brightness and at least one electronic control unit (3) arranged to drive the arrangement (2), wherein the arrangement (2) comprises at least two electrically controllable LED light sources (4, 5, 6), which are in a dominant wavelength of each of them generated Distinguish light from each other, wherein the LED light sources (4, 5, 6) are so controllably designed and arranged to each other that the light emitted from the assembly (2) by additive mixing of the individual LED light sources (4, 5, 6 ) each generated light is generated,
characterized,
in that the electronic control unit (3) is set up to carry out the method according to one of Claims 1 to 8. System (1) according to claim 9, characterized in that the LED light sources (4, 5, 6) comprise the assembly at least one LED light source (4) designed to produce blue light, which has at least one light-emitting diode, at least one LED light source (5) arranged to produce conversion light with a color lying in a conversion range, which has at least one light-emitting diode configured to produce blue light and at least one conversion unit set up for photoluminescence, and / or - At least one adapted to produce red or green light LED light source (6), which has at least one light emitting diode. System (1) according to claim 9 or 10, characterized by at least one temperature sensor (7), with which the temperature of at least one LED light source (4, 5, 6) can be detected. System (1) according to one of Claims 9 to 11, characterized by at least one nonvolatile electronic memory (8) in which information is stored which is used to determine the currents of the individual supply currents for at least one of the at least two of the LED light sources (4, 5, 6) serve. System (1) according to claim 12, characterized in that in the non-volatile electronic memory (8), at least stored: a dependence of the dominant wavelength of the light generated by at least one LED light source (4, 5, 6) on a current intensity of this LED light source (4, 5, 6) supplying direct current or another, this dependency containing information and / or a dependence of the dominant wavelength of the light emitted by the arrangement (2) on a current intensity of the arrangement supplying the arrangement (2) as a whole, or another information containing this dependence, and / or - A dependence of a current strength of at least one LED light source (4, 5, 6) supplying direct current from the current of at least one further LED light source (4, 5, 6) supplying direct current or another, this dependency containing information. System (1) according to claim 13, characterized in that it is stored in the nonvolatile electronic memory a dependence of the dominant wavelength of the light generated by at least one LED light source (4, 5, 6) on the temperature of this LED light source (4, 5, 6) or another information including this dependence, and / or a dependence of the dominant wavelength of the light emitted by the device (2) on a temperature of the device (2) or another information including this dependence.

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