Method for adjusting a luminous color of a lamp, system with a lighting device and motor vehicle

Abstract

Method for setting a luminous color of a lighting means (12) for a motor vehicle (1), comprising the steps of: a) specifying a set of target luminous colors (F, F1, F2, F3, F4) in the form of different color sets for different brands, model series, equipment lines, or target markets of the motor vehicle (1); b) assigning a code to each target luminous color (F, F1, F2, F3, F4) from the specified set of target luminous colors (F, F1, F2, F3, F4); c) assigning at least one control parameter to each code, such that when the code is selected via the at least one control parameter, the luminous color corresponding to the target luminous color (F, F1, F2, F3, F4) is set on the lighting means (12);d) Setting the luminous color by selecting the code, wherein- in step a) the set of target luminous colors (F, F1, F2, F3, F4) is specified in such a way that it completely covers a predefinable gamut (11),- the color difference (Δu'v') of next neighboring target luminous colors (F3, F4) in the CIE-UCS color chart (8) has a value greater than or equal to 0.005,- all target luminous colors (F, F1, F2, F3, F4) specified within the gamut (11) are stored in a table in a memory unit (4) of an RGB module (2), and- at least one control parameter is available precalibrated.;

Description

The invention relates to a method for adjusting a luminous color of a lighting means for a motor vehicle, having the steps: a) presetting a set of setpoint luminous colors; b) assigning a code to each setpoint luminous color from the preset set of setpoint luminous colors; c) assigning at least one control parameter to each code, which code, when the code is selected via the at least one control parameter, adjusts the luminous color corresponding to the setpoint luminous color at the lighting means; and d) adjusting the luminous color by selecting the code.The invention also relates to a system having a control device and a lighting device. Finally, the invention now also relates to a motor vehicle having such a system.For ambient lighting in the interior of motor vehicles, it is known to use lighting means with adjustable lighting color. The light fixture is usually a module with three differently colored light-emitting diodes, wherein the individual light-emitting diodes can be individually controlled. In a so-called RGB (Red Green Blue) LED (Light Emitting Diode) module, a desired luminous color can be individually set within wide ranges by separately setting the luminous intensity of the individual light-emitting diodes via color mixing. In this way, a very large range of colors, the so-called gamut, can be covered via light mixing.The use of RGB LED modules in ambient lighting in the vehicle interior is known, for example, from DE 10 2006 036 060 A1 and DE 10 2006 030 300 A1. DE 10 2006 036 060 A1 describes a motor vehicle with a plurality of lighting devices which are arranged distributed in the interior and by means of which different regions or objects of the vehicle interior can be illuminated. A control unit is provided which controls at least a part of the lighting devices separately with suitable control programs. The control program to be used in each case is selected as a function of one or more information signals describing the vehicle state and / or the driving mode and detected via sensors.DE 10 2006 030 300 A1 likewise describes a motor vehicle having a plurality of lighting devices which are arranged distributed in the interior and which contain at least one lighting means for illuminating the vehicle interior. At least some of the lighting means are RGB LEDs, wherein the color of the light generated thereby can be selected by a person in the motor vehicle or can be changed as a function of at least one operating mode of the motor vehicle selected by the driver or at least one operating or driving parameter of the motor vehicle.Utility model document DE 20 2005 020 801 U1 relates to a luminaire having a memory in which a data record is written which describes at least one property of the lighting means. The data record can contain a measured value of a parameter of the lighting means. The luminaire can have a plurality of colored lighting means, which can comprise a red, green and blue lighting means.European patent EP 2 030 480 B1 describes an apparatus for generating light of different colors. This device includes a lamp assembly, a controller, a user input device, and a memory. In the memory, a predetermined number of hue values, a predetermined number of saturation values, and a predetermined number of brightness values may be included. The control unit may be adapted to compare the user input data with the information in the memory to determine whether a point defined by the coordinates of the user input data is within or outside a boundary of a color space.The published patent application DE 10 2006 055 615 A1 relates to a method for providing control signals for a luminaire whose color or color temperature can be changed. In the method, a series of at least three color loci are determined which lie on a predetermined color change curve in a corresponding coordinate system. The color locations are selected in particular such that respectively correlating colors have a color separation which is subjectively perceived as respectively of the same size.In order to select a desired luminous color, the lighting means are to be controlled in a suitable manner. Essentially two different methods are known here. Thus, according to a first alternative, the color coordinates corresponding to the desired color can be transmitted directly to the lighting means, wherein a microcontroller with a stored calibration curve is provided in the lighting means. On the basis of the colour coordinates, respective control signals for the actuation of the lighting means and thus for the setting of the desired colour are then output. The control parameters for the lighting means are calculated in the microcontroller only after a color selection has been made by a user. In this case, a fixed set of colors need not be set in advance, but the color adjustment can be made very variably. However, this method has the disadvantage that the respective color values or color coordinates corresponding to the desired color must be transmitted to the microcontroller with high resolution (e.g. 10 bits per color value). The amount of data to be transmitted is very large, so that, for example, a bus system with a high data transmission capacity must be provided in the motor vehicle. A further disadvantage is that the respective control parameters or control values for the lighting means are only calculated in the microcontroller, so that time delays or long adjustment times can result for the color adjustment.According to a second alternative, however, it is also possible to define a limited number of colors in advance, especially for a respective application (e.g. series of the motor vehicle, equipment of the motor vehicle, etc.). For each of the selected colors, a suitable set of control parameters for the illuminant and a code value are stored in tabular form. For this purpose, a memory unit can be provided in a microcontroller of the lighting means. Only a code value corresponding to the desired color then needs to be transmitted to the microcontroller, and the associated control parameters are already ready to be precalibrated. The amount of data to be transmitted to the microcontroller is small and no longer has to be used to calculate the control parameters on the basis of a calibration curve in the microcontroller itself. However, only a limited selection of colors is available in this manner and these colors must also already be defined in advance. This substantially limits the possibilities of color selection.It is the object of the invention to provide a method, a system and a motor vehicle, with the aid of which it is possible on the one hand to set the luminous color of a lighting means in a very variable manner and on the other hand to simplify the type of setting.This object is achieved by a method having the features of claim 1, a system having the features of claim 5, and a motor vehicle having the features of claim 9.The method according to the invention serves for setting a luminous color of a lighting means for a motor vehicle and comprises the following steps: a) presetting a set of setpoint luminous colors in the form of different color sets for different marks, series, lines of equipment or target markets of the motor vehicle; b) assigning a code to each setpoint luminous color from the preset set of setpoint luminous colors; c) assigning at least one control parameter to each code, such that, when the code is selected via the at least one control parameter, the luminous color corresponding to the setpoint luminous color is set at the lighting means; d) setting the luminous color by selecting the code. According to the invention, it is provided that in step a) the set of target luminous colors is predefined in such a way that it completely covers a predefinable gamut and that the color separation of next-adjacent target luminous colors on a predefined color chart is so small that the luminous colors corresponding to these target luminous colors can just still be distinguished in color by the human eye.The color separation of next adjacent desired luminous colors in the CIE UCS color chart has a value greater than or equal to 0.005. All desired luminous colors (F, F1, F2, F3, F4) defined within the gamut are stored in a table in a memory unit of an RGB module. The at least one control parameter is ready to be precalibrated.By luminous colour is meant in particular the colour in which the light-emitting lighting means appears to a human. The desired luminous color, on the other hand, can be defined by so-called color locations or color coordinates on a color chart. The colour chart is to be understood as meaning in particular the CIE (Commission Internationale de l'Eclairage) standard colour chart or the CIE UCS (Uniform Colour Scale) colour chart. Code is to be understood in particular as a data record whose data volume is less than the data volume with direct specification of the color coordinates or control parameters. Gamut is understood to mean, in particular, any desired set of colors from a color space. With regard to the color separation, the color perception of the human eye is aimed at, wherein the individual target luminous colors in the set of target luminous colors are to be so close that the color stimuli belonging to the next adjacent target luminous colors are just still distinguishable from an average observer.Because the set of desired luminous colors completely covers the predefinable gamut, an early determination of specific colors is not necessary. The desired luminous colors physiologically cover practically the entire color space within the gamut, since with regard to the color separations, the color grid is selected so finely that an even finer grid would not be distinguishable at all by the human eye. Practically any desired color within the gamut can thus be displayed for human perception. Although each distinguishable color can thus also be actually displayed, it is not necessary to transmit individual control parameters or specific color coordinates to the lighting means in order to also actually set the respective lighting color on the lighting means. It is sufficient to transmit a code assigned to the respective desired luminous color, so that this desired luminous color or the set of control parameters assigned to it can be selected from the set of possible desired luminous colors. In the form of the codes, only very small amounts of data need to be transmitted to the lighting means. A calculation of control parameters to be repeatedly carried out in each case on the basis of a calibration curve, for example, can also be dispensed with. The setting of the luminous colour can thus be carried out in a very flexible manner on the one hand; on the other hand, the outlay for the transmission of data is low. The adjusting time of the luminous colour at the lighting means is also short.The color separation of next adjacent desired luminous colors in the CIE UCS color chart has a value greater than or equal to 0.005. Color differences which are less than 0.005 are generally imperceptible to the human eye. If the color separation is selected with this value, practically any desired color within the predetermined gamut can be displayed. An even finer screen would no longer be perceptible by the human eye. This achieves an optimum compromise between high color resolution on the one hand and a small amount of data on the other hand. Any desired color within the gamut can be set very variably. Nevertheless, the effort required for this is kept low.Preferably, in step a), the set of target luminous colors is predefined in such a way that all the next adjacent target luminous colors in the CIE UCS color chart have the same color separation from one another. Since the CIE UCS chromaticity diagram is optimally matched to the color perception of the human eye or the human sensation, it is also ensured by the selection of color distances of the same type that the color space to be displayed is densely, homogeneously and uniformly filled. Individual colors of light and transitions from one color of light to another can be reproduced very naturally and pleasantly for the human sensation.The gamut is preferably predefined by the maximum color space that can be represented by the luminous colors of the lighting means. The gamut is then in particular the color space which can be displayed to the maximum by internal color mixing in the lighting means. The gamut is then given in particular by the set of all possible colors which can be displayed at all by the lighting means. This embodiment makes it possible to be able to actually display any color that can be displayed technically using a lighting means. Very great possible variations with regard to the selection of colour are obtained.Preferably, in step c), the at least one control parameter is assigned to each code in the form of a table with codes and control parameters. The tabular arrangement makes it possible to assign to a code the control parameters corresponding to the desired luminous color quickly and reliably. The setting of the luminous color at the lighting means is possible quickly and without difficulty.A system according to the invention comprises at least one control device and one lighting device, wherein the lighting device comprises a lighting means and a control unit with a memory unit. The memory unit stores a set of pairs each comprising a code and at least one control parameter assigned to the code, wherein each of the pairs is assigned a desired luminous color. Furthermore, the control device is designed to transmit one of the codes to the control unit, and the control unit is designed to actuate the lighting means by means of the at least one control parameter assigned to the transmitted code, such that a corresponding lighting color is established on the lighting means, which is assigned to the code. In this case, each pair from the set of pairs is assigned a desired luminous color in the form of different color sets for different marks, series, fitting lines or target markets of the motor vehicle in such a way that the desired luminous colors completely cover a predeterminable gamut and that the color separation of the next adjacent desired luminous colors on a predetermined color chart is so small that the luminous colors corresponding to these desired luminous colors can just still be distinguished in color by the human eye.For this purpose, the color separation of next adjacent desired luminous colors in the CIE UCS color chart has a value greater than or equal to 0.005. All the desired luminous colors defined within the gamut are stored in a table in the memory unit of an RGB module. The at least one control parameter is precalibrated.The lighting means preferably comprises three light emitting diodes of different colors, wherein each of the light emitting diodes is assigned a control parameter for each of the desired light colors. Light emitting diodes are very long-lived and energy-efficient. On the other hand, they can be used to represent spectrally very pure colors. Preferably, the three different-colored light-emitting diodes can represent the spectral colors red, green and blue. This is then referred to in particular as an RGB light-emitting diode or an RGB light-emitting diode module. By internally mixing colors, a large amount of possible colors can be represented. The embodiment allows to represent a very large gamut and thus to cover a wide color space. With regard to ambient lighting in a motor vehicle, there are many different possibilities for selecting colors.The lighting device is preferably in the form of a module in which the lighting means, the control unit and the storage unit are structurally integrated. This module can in particular be packaged, i.e. designed such that the lighting means, the control unit and the storage unit are present in a common housing.The control device is preferably designed such that at least two different sets of the codes can be selected via a selection menu, by means of which the control unit can be controlled. From the predefined set of the desired luminous colors, it is accordingly possible to select individual defined desired luminous colors which are intended to be displayed in a targeted manner. Via the selection menu, this selection can be matched in particular to the specific requirements of the interior lighting of a very specific motor vehicle. The interior lighting can thus be matched very individually to different models or series of a motor vehicle.A motor vehicle according to the invention comprises a system according to the invention.The preferred embodiments and the advantages thereof illustrated with reference to the method according to the invention apply correspondingly to the system according to the invention and the motor vehicle according to the invention.The invention is explained in more detail below with reference to exemplary embodiments. The following are shown: FIG. 1 shows a motor vehicle with a lighting means for ambient lighting; FIG. 2A shows a CIE standard table known from the prior art; FIG. 2B shows the CIE norm table of FIG. 2 awith a plurality of selected color locations; FIG. 3A shows a UCS color chart known from the prior art; FIG. 3B illustrates the UCS color chart of FIG. 3A with selected color locations according to an embodiment of the invention; and FIG. 3C shows the region marked by a circle in FIG. 3B in an enlarged illustration with the color distance between the color locations drawn in.In the figures, identical or functionally identical elements are provided with the same reference numerals.FIG. 1 shows a motor vehicle 1 with an RGB module 2 for ambient lighting in the interior of the motor vehicle 1. the RGB module 2 comprises a lighting means 12 which is formed by a red light-emitting diode R, a green light-emitting diode G and a blue light-emitting diode B. In addition, it comprises a microcontroller 3 with a memory unit 4. the RGB module 2 is connected to a control device 5 via a data cable 6. The control device 5 is part of a control unit of the motor vehicle 1.Within the scope of multi-color ambient lighting with the RGB module 2, a very large number of different colors can be set by light mixing. The color locations of the adjustable colors can be displayed in a CIE standard chart 7. The set of possible colors is given by the range within a spectral color line 9 and a purple line 10. Within this range, the gamut 11 of the RGB module 2 is also located. all points or desired luminous colors or color locations within the gamut 11 represent those colors which can also actually be represented by the RGB module 2 by internal color mixing. They can be represented by operating the light-emitting diodes R, G and B in such a way that they have different luminous intensities. The three corners of the gamut triangle 11 are formed by the color coordinates of the individual light emitting diodes R, G and B (i.e. when only one of the light emitting diodes R, G and B is switched on).Usually, only a limited selection of colors is implemented for ambient lighting in the vehicle. The selection of colors is made by the vehicle manufacturer and may vary depending on the brand, series, equipment line, and target market. For a particular motorization or model care, respective colors may be selected. FIG. 2 bshows the CIE standard panel 7 with a possible color selection (color set), to which e.g. the luminous colors F 1 and F 2 belong. The remaining color locations within gamut 11, represented by triangles, also belong to luminous colors of this color selection. The set of these desired luminous colors does not completely cover the predetermined gamut 11, as can be seen from FIG. 2 b. In addition, the color distances vary between next adjacent desired luminous colors.The color coordinates and brightnesses of different RGB modules 2 typically scatter very strongly. Therefore, it is a known method to perform calibration measurement for each individual RGB module 2. The resulting measurement results are then used to calculate a table which, for each luminous color F from the possible color selection, receives associated control parameters for the RGB module 2. This table is stored in the memory unit 4 of the microcontroller 3, specifically separately for each RGB module 2. the desired color in the interior of the motor vehicle 1 is then set by the control device 5 transmitting to the microcontroller 3 a number (code) for the desired setpoint luminous color F. For example, a first code is assigned to the setpoint luminous color F 1 and a second code is assigned to the setpoint luminous color F 2. Suitable control parameters for these codes or desired colors of light F1 and F2 are again stored in the table. The microcontroller 3 takes the control parameters from the table in accordance with the transmitted number and controls the lighting means 12 accordingly. In this way, colors can be adjusted precisely. However, the selection or definition of the luminous colors F must take place in good time before the production of the RGB module 2. Different color sets for different brands, series, equipment lines, target markets, etc. of the motor vehicle 1 lead to a large number of variants of the RGB module 2.These disadvantages can be avoided if only the calibration data of the light emitting diodes R, G and B are stored in the microcontroller 3 instead of a table with a color set. In this case, according to the prior art, the desired color is adjusted by transmitting the color coordinates x, y and the desired brightness from the control device 5 via the data cable 6 to the RGB module 2. The advantage is that no color set has to be determined in advance and therefore there is also only one variant of the RGB module 2. However, this method also has disadvantages. In order to be able to control the colors sufficiently accurately, the color coordinates must be transmitted to microcontroller 3 with a resolution of at least 10 bits each for the x and y values. This is associated with a significantly larger amount of data which has to be transmitted, compared to the method described above. A further disadvantage is that the control parameters for the light emitting diodes R, G and B are only calculated in the microcontroller 3. This leads to a very long setting time for the desired luminous color at the lighting means 12.In the present case, the advantages of both methods are combined. The invention is based on the recognition that the human eye is limited in its ability to distinguish colors. This means that the colour coordinates of two different colours need only have a minimum distance from each other in order to be perceived as different colours. This minimum distance is advantageously not defined via the CIE standard chart 7, but via the UCS color chart 8, which is illustrated in FIG. 3A. The UCS color chart 8 of FIG. 3A results from warping the CIE standard chart 7 of FIG. 2 a, wherein the degree of distortion is determined from the color perception of the human eye. In the CIE standard table 7, the geometric distances of two luminous colors F do not correspond to the distance according to the invention. Therefore, the CIELUV system was introduced in 1976. The UCS chromaticity diagram 8 contained therein is based on a linear transformation of the CIE chromaticity diagram 7. the coordinates or colour components u' and v' are calculated from the x and y values of the CIE chromaticity diagram 7. Thus, in the UCS color chart 8, the geometric distances correspond significantly better to the distances according to the invention than in the CIE standard chart 7, although this representation is also not yet perfect. Therefore, color separations are usually specified today as Δu'v' values. The color separation Δu'v' can then be determined as the Euclidean distance: Δu'v'= SQRT[(Δu') 2+ ( Δv') 2].According to FIG. 3B, a color set is therefore defined which completely fills the gamut 11 of the RGB module 2. This color set is schematically represented by the uniform dot grid of the luminous colors F in FIG. 3B. Here, the set of desired luminous colors F is predefined in such a way that predefined gamut 11 is completely covered and color separation Δu'v' of next adjacent desired luminous colors F on the predefined color chart (UCS color chart 8) is so small that the luminous colors corresponding to these desired luminous methods F can just still be distinguished in color by the human eye.FIG. 3 cshows this relationship in an enlarged manner again. The luminous colors F3 and F4 are next adjacent to one another in the UCS color chart 8 and have the color separation Δu'v' from one another. In the exemplary embodiment, this color separation is Δu'v'=0,005. This is because color differences of Δu'v' less than or equal to 0.005 cannot be recognized by the human eye. All "meaningful" colors that can be distinguished for the human eye can thus be displayed. All these desired luminous colors F defined within the gamut 11 are stored in a table in the memory unit 4 of the RGB module 2. Each of the light colors 11 is assigned a code and a suitable set of control parameters for the control of the light emitting diodes R, G and B.This results in considerable advantages. The color set is defined once, matching the gamut 11 of the light emitting diodes R, G and B. During the calibration of the RGB module 2, the associated control parameters are calculated and stored in a table in the memory unit 4 of the microcontroller 3. The RGB module 2 thus has the capability of being able to represent all distinguishable colors F. The selection of the color F is effected by transmitting an assigned code number to the microcontroller 3. Since no calculation of the control parameters is required in the microcontroller 3, there is also no associated time delay. The adjustment of the color is effected by the microcontroller 3 merely by extracting the control parameters from the table which is stored in the memory unit 4. Thus, only one variant of the RGB module is required. An early determination of the colors F is thus not necessary. As a result, the RGB module 2 can be used across all series of the motor vehicle 1 and year of change. Any desired restriction of the number of colors or a differentiation of the adjustable colors according to marks, series of buildings, lines of equipment, target markets, etc., can be carried out in the operating and display system of the motor vehicle.List of reference characters1 Motor vehicle 2 RGB module 3 microcontroller 4 memory unit 5 control device 6 data cable 7 CIE standard panel 8 UCS color panel 9 spectral color line 10 purple line 11 gamut 12 illuminant R light emitting diode G light emitting diode B light emitting diode F, F1, F2, F3, F4 luminous color ΔE color separation x, y color component u', v' color component

Claims

Method for setting a luminous colour of a lighting means (12) for a motor vehicle (1), having the steps: a) presetting a set of setpoint luminous colours (F, F1, F2, F3, F4) in the form of different colour sets for different marks, series, equipment lines or target markets of the motor vehicle (1); b) assigning a code to each setpoint luminous colour (F, F1, F2, F3, F4) from the preset set of setpoint luminous colours (F, F1, F2, F3, F4); c) assigning at least one control parameter to each code, so that when the code is selected using the at least one control parameter, the lighting color corresponding to the setpoint lighting color (F, F1, F2, F3, F4) is set at the lighting means (12); d) setting the luminous colour by selection of the code, wherein - in step a) the set of desired luminous colours (F, F1, F2, F3, F4) is predetermined in such a way that it completely covers a predeterminable gamut (11), - the colour spacing (Δu'v') of next adjacent desired luminous colours (F3, F4) in the CIE UCS colour chart (8) has a value greater than or equal to 0.005, - all desired luminous colours (F, F1, F2, F3, F4) defined within the gamut (11) are stored in a table in a memory unit (4) of an RGB module (2), and - the at least one control parameter is ready to be precalibrated.Method according to Claim 1, characterized in that, in step a), the set of desired luminous colours (F, F1, F2, F3, F4) is predefined in such a way that all next adjacent desired luminous colours (F3, F4) in the CIE UCS colour chart (8) have the same colour spacing (Δu'v') from one another.Method according to one of the preceding claims, characterized in that the gamut (11) is predefined by the colour space (11) which can be displayed at most by the luminous colours of the lighting means (12).Method according to one of the preceding claims, characterized in that in step c) the at least one control parameter is assigned to each code in the form of a table with codes and control parameters.System having at least one control device (5) and one lighting device (2), wherein the lighting device (2) comprises a lighting means (12) and a control unit (3) having a storage unit (4), wherein a set of pairs of in each case a code and at least one control parameter assigned to the code is stored in the storage unit (4), and wherein each of the pairs is assigned a desired lighting colour (F, F1, F2, F3, F4) in the form of different colour sets for different marks, series, equipment lines or target markets of the motor vehicle (1), wherein the control device (5) is designed to transmit one of the codes to the control unit (3) and the control unit (3) is designed to actuate the lighting means (12) by means of the at least one control parameter assigned to the transmitted code, that a corresponding luminous color is established on the lighting means (12), which is assigned to the code, wherein - each pair of the set of pairs is assigned the desired luminous color (F, F1, F2, F3, F4) in such a way that the desired luminous colors (F, F1, F2, F3, F4) completely cover a predeterminable gamut (11), and - the color spacing (Δu'v') of next-adjacent desired luminous colors (F3, F4) in the CIE UCS color panel (8) has a value greater than or equal to 0.005, - all desired luminous colors (F, F1, F2, F3, which are fixed within the gamut (11), F4) can be stored in a table in the memory unit (4) of an RGB module (2), and the at least one control parameter is ready to be precalibrated.System according to Claim 5, characterized in that the lighting means (12) comprises three light-emitting diodes (R, G, B) of different colors, and a control parameter is assigned in each case to each of the light-emitting diodes (R, G, B) for each of the desired light colors (F, F1, F2, F3, F4).System according to claim 5 or 6, characterised in that the lighting device (2) is in the form of a module (2), in particular a module which is housed and in which the lighting means (12), the control unit (3) and the storage unit (4) are structurally integrated.System according to one of Claims 5 to 7, characterized in that the at least one control device (5) is designed in such a way that at least two different sets of the codes can be selected via a selection menu, by means of which the control unit (3) can be controlled.Motor vehicle (1) comprising a system according to one of Claims 5 to 8.

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