EP3914045B1

EP3914045B1 - Lighting control system and method

Info

Publication number: EP3914045B1
Application number: EP20175254.0A
Authority: EP
Inventors: Chento Didden; Robertus Wilhelmus Paulus Didden
Original assignee: We Did It Again BV
Current assignee: Summa Ip BV
Priority date: 2020-05-18
Filing date: 2020-05-18
Publication date: 2022-05-11
Anticipated expiration: 2040-05-18
Also published as: ES2924269T3; EP3914045A1; WO2021233813A1; DK3914045T3

Description

FIELD OF THE INVENTION

The present invention relates to a lighting system comprising a lighting unit which comprises at least two light sources having different color spectrums, an optical part which is configured to mix the color spectrums of the light sources, and a drive unit which is connected to the lighting unit and which is configured to energize the light sources of the lighting unit. The invention also relates to a method for operating a lighting system as mentioned.

BACKGROUND OF THE INVENTION

In semiconductor-based lighting elements, such as LEDs, the color spectrum and the brightness (intensity) change with increasing operation pressure or force, which can be perceived as interference unless compensation is provided for this interference. In addition, LEDs are also affected by a dispersion of their technical properties with regard to brightness and color during manufacture. This is compensated for by the manufacturer using so-called "binning," in which semiconductor elements are sorted according to a predetermined dispersion.
There are several applications in which a desired light color is generated from three LED light sources with red, green and blue color spectra. The light emitted by the three LEDs can be detected by a three-section filter, and the measured RGB value can be converted to the so-called CIE XYZ color space (CIE=Commission Internationale de I'Eclairage [International Commission on Illumination]). The measured value vector is compared with an XYZ target value in a control unit which functions as a P controller and which, depending on the error, acts upon a drive unit such that the drive unit is made to supply electrical power to the light sources accordingly. By carrying out the actions as mentioned and using the control unit and other means, compensation for changes in the brightness and color of the light emitted by the LED light sources can be provided.
However, a disadvantage in this respect is that the sensor has to be adjusted to the frequency spectra of the LEDs for the control unit to function sufficiently. Furthermore, with this system, a lighting device with more than three light sources having different color spectra can no longer be controlled, because the result of an algorithm of said control unit is no longer unequivocal in view of the fact that several lumen settings of at least four light sources can generate the same color impression in the XYZ color space.
There are also different applications that focus on processes for determining the light current components of individual LEDs via a v(lambda)-adapted sensor. The operationally conditioned color and brightness changes of the individual LEDs are determined by measuring the spectral component with the aid of measuring the operating temperature of the LED (board and junction temperature). These measured values are determined individually for the particular controlled LED. This has the disadvantage that only one individual light source can always be observed by the measuring method used. Even a detection of the color shift of an individual light source can be determined only indirectly with the information of the temperature. Non-temperature-dependent color changes of the light source cannot be differentiated.
WO 2004/100611 A1 discloses an LED lighting module system for precise color output control comprising multiple LEDs having each a different visible light spectra. An optical lens system is provided to direct and transfer radiated light from the LEDs to a desired target and a color mixer is provided to mix color light output of the LEDs.

SUMMARY OF THE INVENTION

It is an objective of the present invention to provide a lighting system comprising a lighting unit, an optical part and a drive unit, and also a method for operating such a lighting system, the system and method being suitable to provide optimized control of light sources with different color spectra and to enable differentiation of temperature changes and non-temperature-dependent color changes in real time.
Aspects of the present invention are set out in the accompanying independent and dependent claims. Features from the dependent claims may be combined with features from the independent claim as appropriate and not merely as explicitly set out in the claims.
At least the abovementioned objective is achieved by a lighting system comprising:

a lighting unit which comprises at least two light sources having different color spectrums,
an optical part which is configured to mix the color spectrums of the light sources,
a drive unit which is connected to the lighting unit and which is configured to energize the light sources of the lighting unit,
at least one sensor which is configured to detect at least one of the junction temperature of the light sources at a position of a connection area between the drive unit and the lighting unit and the temperature of the optical part,
a control unit which is configured to act on the drive unit as a function of predetermined primary data relating to the light sources, the optical part and the drive unit as well as instantaneous secondary data obtained real-time from the lighting unit, the optical part and the drive unit during operation of the lighting system, wherein the control unit is configured to use an optimization algorithm which is designed to calculate control settings of the drive unit on the basis of the predetermined primary data and the instantaneous secondary data for optimizing a value of color consistency of each of the light sources and maximizing life time of each of the light sources, wherein the predetermined primary data include an average age range of a target audience associated with an area in which the lighting system is to be operated, and wherein the instantaneous secondary data include values of at least one of the junction temperature of the light sources and the temperature of the optical part detected by the at least one sensor, and of depreciation in at least one of the lighting unit and the drive unit, during operation of the lighting system.

The lighting unit may include at least four light sources, and the control unit is arranged for using an optimization algorithm which, as a main condition, optimizes a value of color consistency of each of the light sources, such as the color rendering index (CRI), which can be calculated from the predetermined primary data and the instantaneous secondary data.
The predetermined primary data may include previously measured data for each of the light sources, the optical part and the drive unit. Said measured data may be provided as a specification from the manufacturers of at least one of the light sources, the optical part and the drive unit. Said measured data for the light sources may include a predetermined color spectrum, peak wavelength, dominant wavelength, and beam angle in full width and half maximum for each one of the light sources.
The instantaneous secondary data may include any depreciation on the predetermined efficiency of the drive unit and the optical part. Said secondary data may also include a lumen depreciation which may be determined with an error in a predetermined spectral power distribution in the light source during operation of the system.
The control unit is configured to use the optimization algorithm which may result in controlling values of the individual light source. The optimization algorithm may compensate any influences on the color and brightness change, in particular since a redundancy in determination regarding the color impression is generated by using the at least two light sources as compensation source. Additionally, color adaptation can also take place under reduction of the total brightness of the light in that the optimization is carried out in an XYZ color space affected by brightness.
The control unit is configured to carry out the setting of the lighting unit, by means of the drive unit, and by using the optimization algorithm that includes two or more optimization criteria. The optimization goal is to optimize the color consistency of the light sources and to maximize the life time of each of the light sources, wherein the optimization settings are calculated from predetermined primary data that include predetermined measured values for the individual light sources, the optical part and the drive unit, and secondary data that include the junction temperature of the light sources and/or the temperature of the optical part measured by the sensor.
The sensor may be configured to detect the junction temperature of the light sources in the connection area. The sensor may be located near to each of the light sources as close as possible to the drive unit. The number of sensors can be chosen according to the number of the light sources that are used in the system. The temperature difference depends for each connection area on the thermal power to be dissipated from the respective connection area. Since brightness of each of the light sources defined with different wavelength depends on the junction temperature, the measured characteristic lines of the brightness as function of the junction temperature may show a power-dependent curve shape.
The system may be adjusted with the temperature-dependent color correction onto the drive unit in each case. The calculation may be effected in the context of the calibration and the determined results (lumen of the light sources colors depending on the temperature) can be stored as a function in the optimization algorithm.
The optimization goal of the control unit may further be optimizing the color spectrum of the light sources. From predetermined specifications in respect of each light source and the measured junction temperature and the temperature of the optical part, an associated spectrum may be calculated, which is added to the calculated spectra of the other light sources to form a jointly calculated "predetermined" total spectrum. From this calculated total spectrum, the CRI value Ra is calculated in the usual manner, as in the case of measured spectral values. It is preferred for this calculation to occur in the CIE system.
For at least two light sources, there are unlimited possibilities or possibilities only limited by the resolution of the control to adjust a desired chromaticity coordinate of color by mixing the used primary colors. Depending on the mixing ratio, it can be optimized towards different parameters like lumen efficiency or color consistency. The desired chromaticity coordinate color may also be optimized towards the color reproductions properties of the optical part. When the optimization is done, desired chromaticity coordinates x/y may be adjusted.
The control unit may define an ecosystem using an Artificial Intelligence method that gets feedback/input from the light sources, the optical part and the drive unit. Said ecosystem is configured to control the drive unit. Therefore, the system is not bound by a specific drive unit. The Artificial Intelligence method may be combined with machine learning.
Said ecosystem is configured to use a communication protocol depending on the predetermined specifications of the drive unit. Said communication protocol may be the DMX protocol. The DMX protocol may allow a setting of the drive unit current for each light source with a precision of 8 bit (that is 256 different values). Instead of the DMX protocol, other protocols may also be used, for example, protocols with higher precision. It is preferable to provide a control reserve of, for example, one additional bit, in order to appropriately take into consideration the decrease in brightness occurring as a result of aging processes.
The system may be controlled on the basis of human behavior. The average age range of a target audience associated with the area in which the lighting system is to be operated and the times of the day may change the color temperature of said area. Said human behavior may be defined in the predetermined primary data, and may be provided by an end user.
Additionally, the system may be controlled according to the area where the system is used. The mood in the area where the system in use can be changed completely by defined static or dynamic lighting scenes. For example, a kitchen-cum-living room with a high lumen intensity and light with few shadows can be optimized for the needs of work in the kitchen.
The system may be adapted to control the color consistency in the area for a supportive biological effect on health. For example, dynamic light scenes may be defined to create a natural and healthy transition to relaxing sleep in the evening with a reduced, reddish light. In the morning, the special sense cells on the retina are activated to the highest intensity through a higher share of bluish light.
In an embodiment of the system according to the invention, the predetermined primary data include a preset target lumen value.
In an embodiment of the system according to the invention, the predetermined primary data include a preset target correlated color temperature.
The system may be configured to be adjustable by the choice of the light sources and may be controlled with the optimization algorithm that includes, e.g., adjusting the junction temperature to a desired color temperature, brightness and the like. Therefore, the control unit of the system may be adapted to minimize the junction temperature detected by the sensor and a predetermined (target) correlated color temperature which is defined by the end user. For achieving a solution in real time, when the said temperature is found to be above a limit value, the control unit compensates the temperature changes in that area.
The predetermined (target) correlated color temperature and the preset target lumen value of the lighting unit as well as the optical part may be compensated with the optimization algorithm of the control unit in dependency on the junction temperature of the light sources and/or the temperature of the optical part, depreciation in lumen of the light sources, color rendering index and mixed-light capability with the optical part. Accordingly, the control unit may be configured to set control values for the target parameters.
In an embodiment of the system according to the invention, the predetermined primary data include a predetermined pressure value that is allowed to be applied to the lighting unit.
In an embodiment of the system according to the invention, the depreciation in the lighting unit is detectable when a value of pressure that is applied to the lighting unit during operation of the lighting system is larger than the predetermined pressure value.
The lighting unit may be designed to receive a predetermined pressure value that depends on an electric power feed applied to the lighting unit. During operation of the system, said pressure value may increase according to increase or decrease of the electric power feed. This may result in depreciations on the lighting unit, such as efficiency drop on the drive unit and/or optical part, lumen depreciations in the light sources, etc. Therefore the control unit may adapt the lighting system to a desired color consistency from the difference between the predetermined pressure value and the set value of the pressure via a corresponding increase or decrease of the electric power feed to the variously colored light sources during operation of the system.
In an embodiment of the system according to the invention, the control unit is configured to control a lumen value of each of the light sources during operation of the lighting system.
In an embodiment of the system according to the invention, each of the light sources comprises a semiconductor-based light source.
In an embodiment of the system according to the invention, at least a portion of the semiconductor-based light source includes a light emitting diode.
The system may be implemented to any desired light source, particularly any type of light emitting diode, including organic light emitting diodes (OLED). It is also possible to use light sources of different type together, in particular LEDs and incandescent light bulbs.
In an embodiment of the system according to the invention, the optimization algorithm is implementable in a CIE standardized X, Y, Z color space.
In an embodiment of the system according to the invention, the optimization algorithm is configured to realize a value of the color consistency lower than 10 Kelvin.
In an embodiment of the system according to the invention, the control unit is configured to dim each of the light sources during operation of the lighting system.
According to another aspect of the present invention, a method for operating a lighting system with a lighting unit which comprises at least two light sources having different color spectrums, with an optical part which is configured to mix the color spectrums of the light sources, with a drive unit which is connected to the lighting unit and which is configured to energize the light sources of the lighting unit, with at least one sensor which is configured to detect at least one of the junction temperature of the light sources at a position of a connection area between the drive unit and the lighting unit and the temperature of the optical part, and with a control unit which is configured to optimize a value of color consistency of each of the light sources and to maximize life time of each of the light sources, and configured to act on the drive unit, wherein the method comprises:

collecting predetermined primary data relating to the light sources, the optical part and the drive unit,
obtaining instantaneous secondary data real-time from the lighting unit, the optical part and the drive unit during operation of the lighting system, wherein the instantaneous secondary data include values of at least one of the junction temperature of the light sources and the temperature of the optical part detected by the at least one sensor, and of the depreciation in at least one of the lighting unit and the drive unit, during operation of the lighting system,
calculating control settings of the drive unit on the basis of the predetermined primary data and the instantaneous secondary data, and
controlling the drive unit in accordance with the calculated control settings.

The method may enable the control unit to start from different approaches with different adjustment accuracies for achieving an adjustment of the color consistency of light, color temperature or the chromaticity coordinate of the lighting unit that depends on the junction temperature of the light sources.
In an embodiment of the method according to the invention, the predetermined primary data include a predetermined pressure value that is allowed to be applied to the lighting unit.
In an embodiment of the method according to the invention, the depreciation in the lighting unit is detectable when a value of pressure that is applied to the lighting unit during operation of the lighting system is larger than the predetermined pressure value.
In an embodiment of the method according to the invention, the method further comprises:

controlling a lumen value of each of the light sources during operation of the lighting system in accordance with the calculated control settings.

The control unit according to the method may be adapted to minimize the temperature measured by the sensor and a predetermined (target) correlated color temperature which is defined by the end user. For achieving a solution in real time, when the said temperature falls above a limit value, the control unit compensates the temperature changes in that area.
The predetermined (target) correlated color temperature and the preset target lumen value of the lighting unit as well as the optical part may be compensated with the optimization algorithm of the control unit in dependency on the junction temperature of the light sources, depreciation in lumen of the light sources, color rendering index and mixed-light capability with the optical part. Accordingly, the control unit may be configured to set lumen values for the target parameters.
It can be understood that the embodiments of the method according to the invention may include a lighting system having any of the features or combinations of features that are disclosed herein in connection with discussions of the lighting system according to the invention. Accordingly, the entireties of the earlier discussions of the lighting system are hereby incorporated into this discussion of the examples of the method.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the invention will become apparent from the description of the invention by way of exemplary and non-limiting embodiments of a lighting system.
The person skilled in the art will appreciate that the described embodiments of the system according to the present invention are exemplary in nature only and not to be construed as limiting the scope of protection in any way. The person skilled in the art will realize that alternatives and equivalent embodiments of the object can be conceived and reduced to practice without departing from the scope of protection of the present invention.
Reference will be made to the figures on the accompanying drawing sheets. The figures are schematic in nature and therefore not necessarily drawn to scale. Further, equal reference numerals denote equal or similar parts. On the attached drawing sheets,

figure 1 illustrates a schematic block diagram of a lighting system in accordance with an embodiment of the invention; and
figure 2 illustrates a flow chart of a method for operating a lighting system in accordance with another embodiment of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

Figure 1 is a block diagram illustrating an exemplary lighting system 100 according to an embodiment of the present invention. In this embodiment, the lighting system 100 includes a lighting unit 110 having four light sources 111, 112, 113, 114, and further includes a drive unit 115, an optical part 116, two sensors 117, 118 and a control unit 140. As indicated in Figure 1, the control unit 140 is configured to act on the drive unit 115 as a function of predetermined primary data 120 relating to the light sources 111, 112, 113, 114, the optical part 116 and the drive unit 115 as well as instantaneous secondary data 130 obtained real-time from the lighting unit 110, the optical part 116 and the drive unit 115 during operation of the lighting system 100.
The system 100 may include any suitable light sources 111, 112, 113, 114 having different color spectrums, particularly any type of light emitting diode, including organic light emitting diodes (OLED). It is also possible to use light sources 111, 112, 113, 114 of different types together, in particular LEDs and incandescent light bulbs.
Optionally, the light unit 110 may include multiple light sources 111, 112, 113, 114 that may be monochromatic or polychromatic. In some embodiments, each of light sources 111, 112, 113, 114 may produce a monochromatic light having a single wavelength or a narrow SPD with a single peak. In other embodiments, each of light sources 111, 112, 113, 114 may produce a polychromatic light having multiple different peaks in its SPD. Furthermore, in some embodiments, each of light sources 111, 112, 113, 114 may be any type of light source capable of emitting single wavelength light or light with a narrow SPD with a single peak, such as an LED, high pressure sodium lamp (HPS), fluorescent lamp (FL), or the like, or any combination thereof. Considering different kinds of light sources, it is noted that multi-package LEDs are flexible in spectral composition, and spectrum proportions of each LED are easy to control. For example, in some embodiments, by choosing different drive units 115, a variety of LEDs with different spectra could be obtained.
In some embodiments, chromaticity of each light source 111, 112, 113, 114 may correspond to a specific chromaticity coordinate on a chromaticity diagram, which in turn may correspond to a specific color presented on the chromaticity diagram.
For example, as shown in Figure 1, the lighting unit 110 may comprise four component light sources 111, 112, 113, 114. As described above, each component light source 111, 112, 113, 114 may emit light having a specific color. For example, in some embodiments, the four colors may be red, amber, green and blue. In various embodiments, any colors presented on the chromaticity diagram may be used. A polychromatic desired light having desired optical characteristics may be produced by mixing the component lights according to certain proportions. In some embodiments, proportions of the component lights may correlate with each other. Particularly, in some embodiments, proportion of one component light may assume a linear relationship with proportion of another component light. It shall be noted that the above description of the light emitting device is provided for illustration purposes, and is not intended to limit the scope of the present disclosure. For persons of ordinary skill in the art, various variations and modifications may be conducted under the teaching of the present disclosure. For example, the lighting unit 110 may have any number of component light sources 111, 112, 113, 114, each light source 111, 112, 113, 114 may produce a component light of any color, and a component light may be a monochromatic or polychromatic light.
The drive unit 115 may drive the light sources 111, 112, 113, 114 by providing them with voltage or current at calculated levels. The drive unit 115 may receive a command from the control unit 140, and adjust driving voltage or current for individual light sources 111, 112, 113, 114 accordingly. The control unit 140 may be configured to select and determine parameters for spectrum optimization based on the predetermined primary data 120 and the secondary data 130. For example, the control unit 140 may calculate respective proportions of multiple component lights to be combined to generate a desired light having a desirable synthesized chromaticity which is defined by a desired color consistency. In some embodiments, the secondary data 130 may provide the control unit 140 information regarding a working condition of the lighting system 100. As used herein, the term "working condition" broadly relates to any condition or circumstance under which a lighting solution operates, which includes but is not limited to the purpose or goal of the lighting, the target object or environment to be illuminated, the requirement or input by a system default or a user, etc. In some embodiments, information regarding the working condition relates to conditions of an ambient environment of a target object and may be acquired by a detector, transmitted from a local storage device or a remote server, or manually input by a user, or the like, or a combination thereof.
In some embodiments, the control unit 140 calculates respective proportions of component lights based on the component chromaticity and the desired chromaticity. As used herein, the term "component chromaticity" refers to the chromaticity of a component light, and the term "desired chromaticity" or "synthesized chromaticity" refers to the chromaticity of the desired light. In some embodiments, the secondary data 130 may include the component and desired chromaticity received from the end user and transmits the values to the control unit 140.
The control unit 140 may use an optimization algorithm which is designed to calculate control settings of the drive unit 115 on the basis of the predetermined primary data 120 and the instantaneous secondary data 130 for optimizing a value of color consistency of each of the light sources 111, 112, 113, 114 and maximizing life time of each of the light sources 111, 112, 113, 114. The predetermined primary data 120 include a user indication 122 that provides an average age range of a target audience associated with an area in which the lighting system is to be operated. The instantaneous secondary data 130 may include values of the junction temperature 131 of the light sources 111, 112, 113, 114 detected by the sensor 117, the temperature 133 of the optical part 116 detected by the sensor 118, and depreciation 132 in at least one of the lighting unit 110 and the drive unit 115, during operation of the lighting system.
For example, with four component light sources 111, 112, 113, 114, there might be unlimited possibilities or possibilities only limited by the resolution of the control to adjust a desired chromaticity coordinate color by mixing the used primary colors. Depending on the mixing ratio, it can be optimized towards different parameters like lumen efficiency or color consistency. The color consistency may be optimized towards the color reproductions properties of the optical part 116. When the optimization is done, desired chromaticity coordinates x/y may be adjusted.
The predetermined primary data 120 may include previously measured data 121 for each one the light sources 111, 112, 113, 114, the drive unit 115 and the optical part 116. Said measured data may be provided as a specification from the manufacturers of at least one of the drive unit 115, the light sources 111, 112, 113, 114 and the optical part 116. Said measured data for the light sources 111, 112, 113, 114 may include a predetermined color spectrum, peak wavelength, dominant wavelength, and beam angle in full width and half maximum for each one of the light sources.
The instantaneous secondary data 130 may include any depreciation 132 on the predetermined efficiency of the drive unit 115 and the optical part 116. Said secondary data 130 may also include a lumen depreciation which may be determined with an error in a predetermined spectral power distribution in the light source 111, 112, 113, 114 during operation of the system.
Figure 2 is a flow chart of a method showing an example 200 of operating the lighting system 100. The example 200 of the process starts at step 210. Step 210 of the method 200 includes collecting predetermined primary data 120 relating to the light sources 111, 112, 113, 114, the optical part 116 and the drive unit 115. Step 220 of the method 200 includes obtaining instantaneous secondary data 130 real-time from the lighting unit 110, the optical part 116 and the drive unit 115 during operation of the lighting system 100. Step 230 of the method 200 includes calculating control settings of the drive unit 116 on the basis of the predetermined primary data 120 and the instantaneous secondary data 130. Step 240 of the method includes controlling the drive unit 116 in accordance with the calculated control settings. The method 200 may then end at step 240.
In some embodiments, step 240 may include controlling a lumen value of each of the light sources 111, 112, 113, 114 during operation of the lighting system 100 in accordance with the calculated control settings.
It is understood that steps 210, 220, 230, 240 of the method 200 may include a lighting system having any of the features or combinations of features that are disclosed herein in connection with discussions of the lighting system 100. Accordingly, the disclosure of Figure 1 and all aspects of the earlier discussions of the lighting system 100 are hereby incorporated into the present discussion of the examples of the method 200.
The present invention can be summarized as relating to a lighting system 100 with a lighting unit 110 which comprises at least two light sources 111, 112, 113, 114 having different color spectrums, with an optical part 116 which is configured to mix the color spectrums of the light sources 111, 112, 113, 114, with a drive unit 116 which is connected to the lighting unit 110, with a sensor 117, 118 which is configured to detect at least one of the junction temperature 131 of the light sources 111, 112, 113, 114 at a position of a connection area between the drive unit 115 and the lighting unit 110 and the temperature 133 of the optical part 116, and with a control unit 140 which is configured to optimize a value of color consistency of each of the light sources 111, 112, 113, 114 and to maximize life time of each of the light sources 111, 112, 113, 114, and configured to act on the drive unit 116.
It will be clear to a person skilled in the art that the scope of the present invention is not limited to the examples discussed in the foregoing but that several amendments and modifications thereof are possible without deviating from the scope of the present invention as defined by the attached claims.

REFERENCE LIST

100: lighting system
110: lighting unit
111, 112, 113, 114: light sources
115: drive unit
116: optical part
117, 118: sensors
120: predetermined primary data
121: predetermined measurements
122: user indication
130: instantaneous secondary data
131: junction temperature
132: depreciation data
133: temperature of the optical part
140: control unit

Claims

A lighting system (100), comprising:
- a lighting unit (110) which comprises at least two light sources (111, 112, 113, 114) having different color spectrums,

- an optical part (116) which is configured to mix the color spectrums of the light sources (111, 112, 113, 114),

- a drive unit (115) which is connected to the lighting unit (110) and which is configured to energize the light sources (111, 112, 113, 114) of the lighting unit (110),

- at least one sensor (117, 118) which is configured to detect at least one of the junction temperature (131) of the light sources (111, 112, 113, 114) at a position of a connection area between the drive unit (115) and the lighting unit (110) and the temperature of the optical part (116),

- a control unit (140) which is configured to act on the drive unit (115) as a function of predetermined primary data (120) relating to the light sources (111, 112, 113, 114), the optical part (116) and the drive unit (115) as well as instantaneous secondary data (130) obtained real-time from the lighting unit (110), the optical part (116) and the drive unit (115) during operation of the lighting system (100),
wherein the control unit (140) is configured to use an optimization algorithm which is designed to calculate control settings of the drive unit (115) on the basis of the predetermined primary data (120) and the instantaneous secondary data (130) for optimizing a value of color consistency of each of the light sources (111, 112, 113, 114), the lighting system (100) being characterized in that
the control unit (140) is further configured to use the optimization algorithm for maximizing a life time of each of the light sources (111, 112, 1132, 114), and

wherein the predetermined primary data (120) include an average age range of a target audience associated with an area in which the lighting system (100) is to be operated, and

wherein the instantaneous secondary data (130) include values of at least one of the junction temperature (131) of the light sources (111, 112, 113, 114) and the temperature of the optical part (133) detected by the at least one sensor (117, 118), and of depreciation (132) in at least one of the lighting unit (110) and the drive unit (115), during operation of the lighting system (100).
The lighting system (100) according to claim 1, wherein the predetermined primary data (120) include a preset target lumen value.
The lighting system (100) according to claims 1 or 2, wherein the predetermined primary data (120) include a preset target correlated color temperature.
The lighting system (100) according to any of claims 1-3, wherein the predetermined primary data (120) include a predetermined pressure value that is allowed to be applied to the lighting unit (110).
The lighting system (100) according to claim 4, wherein the depreciation (132) in the lighting unit (110) is detectable when a value of pressure that is applied to the lighting unit (110) during operation of the lighting system (100) is larger than the predetermined pressure value.
The lighting system (100) according to any of claims 1-5, wherein the control unit (140) is configured to control a lumen value of each of the light sources (111, 112, 113, 114) during operation of the lighting system (100).
The lighting system (100) according to any of claims 1-6, wherein each of the light sources (111, 112, 113, 114) comprises a semiconductor-based light source.
The lighting system (100) according to claim 7, wherein at least a portion of the semiconductor-based light source includes a light emitting diode.
The lighting system (100) according to any of claims 1-8, wherein the optimization algorithm is implementable in a CIE standardized X, Y, Z color space.
The lighting system (100) according to any of claims 1-9, wherein the optimization algorithm is configured to realize a value of the color consistency lower than 10 Kelvin.
The lighting system (100) according to any of claims 1-10, wherein the control unit (140) is configured to dim each of the light sources (111, 112, 113, 114) during operation of the lighting system (100).
A method (200) for operating a lighting system (100) with a lighting unit (110) which comprises at least two light sources (111, 112, 113, 114) having different color spectrums, with an optical part (116) which is configured to mix the color spectrums of the light sources (111, 112, 113, 114), with a drive unit (116) which is connected to the lighting unit (110) and which is configured to energize the light sources (111, 112, 113, 114) of the lighting unit (110), with at least one sensor (117, 118) which is configured to detect at least one of the junction temperature (131) of the light sources (111, 112, 113, 114) at a position of a connection area between the drive unit (115) and the lighting unit (110) and the temperature of the optical part (116), and with a control unit (140) which is configured to optimize a value of color consistency of each of the light sources (111, 112, 113, 114) and to maximize life time of each of the light sources (111, 112, 113, 114), and configured to act on the drive unit (116), wherein the method comprises:
- collecting (210) predetermined primary data (120) relating to the light sources (111, 112, 113, 114), the optical part (116) and the drive unit (115),

- obtaining (220) instantaneous secondary data (130) real-time from the lighting unit (110), the optical part (116) and the drive unit (115) during operation of the lighting system (100), wherein the instantaneous secondary data (130) include values of at least one of the junction temperature (131) of the light sources (111, 112, 113, 114) and the temperature (133) of the optical part (116) detected by the at least one sensor (117, 118), and of a depreciation (132) in at least one of the lighting unit (110) and the drive unit (116), during operation of the lighting system (100),

- calculating (230) control settings of the drive unit (116) on the basis of the predetermined primary data (120) and the instantaneous secondary data (130), and

- controlling the drive unit (116) in accordance with the calculated control settings.
The method according to claim 12, wherein the predetermined primary data (120) include a predetermined pressure value that is allowed to be applied to the lighting unit (110).
The method according to claim 13, wherein the depreciation (132) in the lighting unit (110) is detectable when a value of pressure that is applied to the lighting unit (110) during operation of the lighting system (100) is larger than the predetermined pressure value.
The method according to any of claims 12-14, further comprising:
- controlling a lumen value of each of the light sources (111, 112, 113, 114) during operation of the lighting system (100) in accordance with the calculated control settings.